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Sample records for zirconium nitrates

  1. Development of a continuous process for adjusting nitrate, zirconium, and free hydrofluoric acid concentrations in zirconium fuel dissolver product

    SciTech Connect

    Cresap, D.A.; Halverson, D.S.

    1993-04-01

    In the Fluorinel Dissolution Process (FDP) upgrade, excess hydrofluoric acid in the dissolver product must be complexed with aluminum nitrate (ANN) to eliminate corrosion concerns, adjusted with nitrate to facilitate extraction, and diluted with water to ensure solution stability. This is currently accomplished via batch processing in large vessels. However, to accommodate increases in projected throughput and reduce water production in a cost-effective manner, a semi-continuous system (In-line Complexing (ILC)) has been developed. The major conclusions drawn from tests demonstrating the feasibility of this concept are given in this report.

  2. Nitrate

    Integrated Risk Information System (IRIS)

    Nitrate ; CASRN 14797 - 55 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effects

  3. Radiochemical separation of zirconium and hafnium from other radionuclides.

    PubMed

    Hahn, R B

    1972-11-01

    Radiozirconium and radiohafnium may be separated from all other radionuclides except scandium and protactinium by precipitation with mandelic acid from 5-10 M hydrochloric acid, using commercial zirconyl chloride as carrier. Scandium and protactinium are removed by dissolving the precipitate in sodium carbonate, then adding barium nitrate to precipitate barium carbonate which acts as a scavenger. Zirconium mandelate is finally reprecipitated and the sample weighed and counted in this form. The method was checked by analysing commercial zirconyl chloride and standard rock samples for zirconium and hafnium by neutron-activation analysis. PMID:18961201

  4. Nitrate reduction

    DOEpatents

    Dziewinski, Jacek J. (Los Alamos, NM); Marczak, Stanislaw (Los Alamos, NM)

    2000-01-01

    Nitrates are reduced to nitrogen gas by contacting the nitrates with a metal to reduce the nitrates to nitrites which are then contacted with an amide to produce nitrogen and carbon dioxide or acid anions which can be released to the atmosphere. Minor amounts of metal catalysts can be useful in the reduction of the nitrates to nitrites. Metal salts which are formed can be treated electrochemically to recover the metals.

  5. Nitrate and periplasmic nitrate reductases

    PubMed Central

    Sparacino-Watkins, Courtney; Stolz, John F.; Basu, Partha

    2014-01-01

    The nitrate anion is a simple, abundant and relatively stable species, yet plays a significant role in global cycling of nitrogen, global climate change, and human health. Although it has been known for quite some time that nitrate is an important species environmentally, recent studies have identified potential medical applications. In this respect the nitrate anion remains an enigmatic species that promises to offer exciting science in years to come. Many bacteria readily reduce nitrate to nitrite via nitrate reductases. Classified into three distinct types – periplasmic nitrate reductase (Nap), respiratory nitrate reductase (Nar) and assimilatory nitrate reductase (Nas), they are defined by their cellular location, operon organization and active site structure. Of these, Nap proteins are the focus of this review. Despite similarities in the catalytic and spectroscopic properties Nap from different Proteobacteria are phylogenetically distinct. This review has two major sections: in the first section, nitrate in the nitrogen cycle and human health, taxonomy of nitrate reductases, assimilatory and dissimilatory nitrate reduction, cellular locations of nitrate reductases, structural and redox chemistry are discussed. The second section focuses on the features of periplasmic nitrate reductase where the catalytic subunit of the Nap and its kinetic properties, auxiliary Nap proteins, operon structure and phylogenetic relationships are discussed. PMID:24141308

  6. Electroless deposition process for zirconium and zirconium alloys

    DOEpatents

    Donaghy, R. E.; Sherman, A. H.

    1981-08-18

    A method is disclosed for preventing stress corrosion cracking or metal embrittlement of a zirconium or zirconium alloy container that is to be coated on the inside surface with a layer of a metal such as copper, a copper alloy, nickel, or iron and used for holding nuclear fuel material as a nuclear fuel element. The zirconium material is etched in an etchant solution, desmutted mechanically or ultrasonically, oxidized to form an oxide coating on the zirconium, cleaned in an aqueous alkaline cleaning solution, activated for electroless deposition of a metal layer and contacted with an electroless metal plating solution. This method provides a boundary layer of zirconium oxide between the zirconium container and the metal layer. 1 fig.

  7. Electroless deposition process for zirconium and zirconium alloys

    DOEpatents

    Donaghy, Robert E. (Wilmington, NC); Sherman, Anna H. (Wilmington, NC)

    1981-01-01

    A method is disclosed for preventing stress corrosion cracking or metal embrittlement of a zirconium or zirconium alloy container that is to be coated on the inside surface with a layer of a metal such as copper, a copper alloy, nickel, or iron and used for holding nuclear fuel material as a nuclear fuel element. The zirconium material is etched in an etchant solution, desmutted mechanically or ultrasonically, oxidized to form an oxide coating on the zirconium, cleaned in an aqueous alkaline cleaning solution, activated for electroless deposition of a metal layer and contacted with an electroless metal plating solution. This method provides a boundary layer of zirconium oxide between the zirconium container and the metal layer.

  8. Process for purifying zirconium sponge

    SciTech Connect

    Abodishish, H.A.M.; Kimball, L.S.

    1992-03-31

    This patent describes a Kroll reduction process wherein a zirconium sponge contaminated with unreacted magnesium and by-product magnesium chloride is produced as a regulus, a process for purifying the zirconium sponge. It comprises: distilling magnesium and magnesium chloride from: a regulus containing a zirconium sponge and magnesium and magnesium chloride at a temperature above about 800{degrees} C and at an absolute pressure less than about 10 mmHg in a distillation vessel to purify the zirconium sponge; condensing the magnesium and the magnesium chloride distilled from the zirconium sponge in a condenser; and then backfilling the vessel containing the zirconium sponge and the condenser containing the magnesium and the magnesium chloride with a gas; recirculating the gas between the vessel and the condenser to cool the zirconium sponge from above about 800{degrees} C to below about 300{degrees} C; and cooling the recirculating gas in the condenser containing the condensed magnesium and the condensed magnesium chloride as the gas cools the zirconium sponge to below about 300{degrees} C.

  9. Synthesis, characterization and optical properties of novel N donor ligands-chelated zirconium(IV) complexes

    NASA Astrophysics Data System (ADS)

    Shahroosvand, Hashem; Nasouti, Fahimeh; Mohajerani, Ezeddin; Khabbazi, Amir

    2012-11-01

    Novel zirconium complexes have been synthesized by using a mixture of zirconium nitrate, 1,2,4,5-benzen tetracarboxylic acid (H4btec), 1,10-phenanthroline(phen) and potassium thiocyanate. Monodentate coordination mode of btec acid for all complexes was investigated by FT-IR spectroscopy. The complexes were also characterized by UV-Vis, 1H NMR, CHN, ICP-AES. The reaction details and features were described and discussed. The photoluminescence emission of seven zirconium complexes was shown two series peaks: first, sharp and intense bands from 300 to 500 nm and broadened with less intensity from 650 to 750 nm for the second bands. Each of the zirconium compounds were doped in PVK:PBD blend as host. The ratio of zirconium complexes for each type were modified 8 wt.% in PVK:PBD(100:40). The electroluminescence spectra of zirconium complexes were indicated a red shift rather than PVK:PBD blend. We suggest that the electroplex occurring at PVK-Zr complex interface.

  10. 21 CFR 181.33 - Sodium nitrate and potassium nitrate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 false Sodium nitrate and potassium nitrate. 181.33 Section 181.33 ...Ingredients § 181.33 Sodium nitrate and potassium nitrate. Sodium nitrate and potassium nitrate are subject to prior sanctions...

  11. 21 CFR 181.33 - Sodium nitrate and potassium nitrate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2009-04-01 true Sodium nitrate and potassium nitrate. 181.33 Section 181.33 ...Ingredients § 181.33 Sodium nitrate and potassium nitrate. Sodium nitrate and potassium nitrate are subject to prior sanctions...

  12. 21 CFR 181.33 - Sodium nitrate and potassium nitrate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Sodium nitrate and potassium nitrate. 181.33 Section 181.33 ...Ingredients § 181.33 Sodium nitrate and potassium nitrate. Sodium nitrate and potassium nitrate are subject to prior sanctions...

  13. 21 CFR 181.33 - Sodium nitrate and potassium nitrate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 false Sodium nitrate and potassium nitrate. 181.33 Section 181.33 ...Ingredients § 181.33 Sodium nitrate and potassium nitrate. Sodium nitrate and potassium nitrate are subject to prior sanctions...

  14. 21 CFR 181.33 - Sodium nitrate and potassium nitrate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 false Sodium nitrate and potassium nitrate. 181.33 Section 181.33 ...Ingredients § 181.33 Sodium nitrate and potassium nitrate. Sodium nitrate and potassium nitrate are subject to prior sanctions...

  15. 33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions...126.28 Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo...

  16. 33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions...126.28 Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo...

  17. 33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions...126.28 Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo...

  18. 33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions...126.28 Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo...

  19. 33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions...126.28 Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo...

  20. 40 CFR 721.10598 - Lead strontium titanium zirconium oxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Lead strontium titanium zirconium oxide. 721.10598...Chemical Substances § 721.10598 Lead strontium titanium zirconium oxide. (a...chemical substance identified as lead strontium titanium zirconium oxide (PMN...

  1. 40 CFR 721.10598 - Lead strontium titanium zirconium oxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Lead strontium titanium zirconium oxide. 721.10598...Chemical Substances § 721.10598 Lead strontium titanium zirconium oxide. (a...chemical substance identified as lead strontium titanium zirconium oxide (PMN...

  2. Zirconium in a sulfuric acid pickling application

    SciTech Connect

    Yau, T.L.

    1988-01-01

    In 1972, Goodyear discovered that zirconium was an ideal material to construct heating coils for sulfuric acid picking tanks. Recently, localized corrosion and high uniform corrosion were reported with certain zirconium coils. The problems could be attributed to the contamination of chloride and/or fluoride ions. Results of electrochemical and immersion tests are used to discuss the effects of acid concentration and acid impurities, such as iron, chloride and fluoride ions, on zirconium's corrosion properties in H/sub 2/SO/sub 4/. Possible sources for acid impurities are identified. Recommendations are made for steel picking when zirconium equipment is used.

  3. Spectrophotometric determination of zirconium with xylenol orange

    SciTech Connect

    Antepenko, R J

    1982-05-14

    High purity hydride forming metal films are used as hydrogen isotope occluders and function as electrodes in neutron generator tubes. This use of zirconium occluder films requires reliable analytical methods for routine determination of the zirconium film weight in a production environment. In this study, a spectrophotometric method was evaluated for the determination of zirconium films. The method is based upon the formation of a highly colored zirconium complex with xylenol orange in a dilute perchloric acid medium. Dilute hydrofluoric acid is used in this procedure to selectively dissolve the zirconium film off the substrate. A perchloric acid fuming step is used to remove hydrofluoric acid from the solution. The zirconium solutions are depolymerized before complex formation by heating in 2 N perchloric acid. The zirconium complex exhibits a maximum absorbance in 0.2 to 0.3 M perchloric acid at a wavelength of 531 nanometers. Beer's law is obeyed for zirconium concentrations through 2.1 parts per million. Molybdenum, at concentrations equal to zirconium, does not interfere with the xylenol orange method.

  4. Zirconium mobility in bauxites of Southern Brazil

    NASA Astrophysics Data System (ADS)

    Melfi, A. J.; Subies, F.; Nahon, D.; Formoso, M. L. L.

    1996-07-01

    A geochemical study of the behaviour of zirconium in bauxites developed on alkaline rocks in southern Brazil is presented. Zirconium, generally considered as an immobile element during weathering, shows an important mobility conditioned to the original Zr bearing parent mineral. In the two areas (Poços de Caldas and Lages) zircon is rare and the zirconium bearing parent minerals are complex weathered silicates as "giannettite", eudyalite, astrophyllite, etc. Since the first stages of weathering, zirconium is partially leached of from the bauxite profile and the remaining Zr is incorporated in secondary phases of the bauxite (amorphous ferric oxydes and aluminous goethite).

  5. Alkali metal nitrate purification

    DOEpatents

    Fiorucci, Louis C. (Hamden, CT); Morgan, Michael J. (Guilford, CT)

    1986-02-04

    A process is disclosed for removing contaminants from impure alkali metal nitrates containing them. The process comprises heating the impure alkali metal nitrates in solution form or molten form at a temperature and for a time sufficient to effect precipitation of solid impurities and separating the solid impurities from the resulting purified alkali metal nitrates. The resulting purified alkali metal nitrates in solution form may be heated to evaporate water therefrom to produce purified molten alkali metal nitrates suitable for use as a heat transfer medium. If desired, the purified molten form may be granulated and cooled to form discrete solid particles of purified alkali metal nitrates.

  6. Method for preparing hydrous zirconium oxide gels and spherules

    DOEpatents

    Collins, Jack L.

    2003-08-05

    Methods for preparing hydrous zirconium oxide spherules, hydrous zirconium oxide gels such as gel slabs, films, capillary and electrophoresis gels, zirconium monohydrogen phosphate spherules, hydrous zirconium oxide spherules having suspendable particles homogeneously embedded within to form a composite sorbent, zirconium monohydrogen phosphate spherules having suspendable particles of at least one different sorbent homogeneously embedded within to form a composite sorbent having a desired crystallinity, zirconium oxide spherules having suspendable particles homogeneously embedded within to form a composite, hydrous zirconium oxide fiber materials, zirconium oxide fiber materials, hydrous zirconium oxide fiber materials having suspendable particles homogeneously embedded within to form a composite, zirconium oxide fiber materials having suspendable particles homogeneously embedded within to form a composite and spherules of barium zirconate. The hydrous zirconium oxide spherules and gel forms prepared by the gel-sphere, internal gelation process are useful as inorganic ion exchangers, catalysts, getters and ceramics.

  7. Method of making crack-free zirconium hydride

    DOEpatents

    Sullivan, Richard W. (Denver, CO)

    1980-01-01

    Crack-free hydrides of zirconium and zirconium-uranium alloys are produced by alloying the zirconium or zirconium-uranium alloy with beryllium, or nickel, or beryllium and scandium, or nickel and scandium, or beryllium and nickel, or beryllium, nickel and scandium and thereafter hydriding.

  8. Drinking Water Problems: Nitrates 

    E-print Network

    Dozier, Monty; Melton, Rebecca; Hare, Michael; Hopkins, Janie; Lesikar, Bruce J.

    2008-03-28

    is contaminated by fertilizers, it may also contain other agricultural chemicals besides nitrates, such as pesti- cides. What happens to nitrates/nitrites in the environment? In natural waters, most nitrogenous materials tend to be converted to nitrate. So you... for discharging the waste- water produced by the treatment process The RO unit operates by passing water under pres- sure though a semi-permeable membrane (Fig. 4). The membrane allows water to pass through but blocks the nitrate. You can improve the nitrate...

  9. Mesoporous zirconium phosphate from yeast biotemplate.

    PubMed

    Tian, Xiuying; He, Wen; Cui, Jingjie; Zhang, Xudong; Zhou, Weijia; Yan, Shunpu; Sun, Xianan; Han, Xiuxiu; Han, Shanshan; Yue, Yuanzheng

    2010-03-01

    Mesoporous zirconium phosphate has attracted increasing interest due to its extraordinary functionalities. In particular, great progress has been made in the synthesis of mesoporous zirconium phosphate using traditional approaches. However, synthesis of mesoporous zirconium phosphate using yeast as biotemplate has not been well studied so far. Here, we show that zirconium phosphate with a mesoporous structure has been synthesized under ambient conditions using yeast as biotemplate. The derived samples were examined by X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), thermogravimetry/differential thermal analysis (TG/DTA), fourier transform infrared spectroscopy (FTIR), and N(2) adsorption-desorption isotherms. A biotemplated mesoporous zirconium phosphate, possessing a specific surface area (Brunauer-Emmett-Teller, BET) of 217.64 m(2) g(-1), a narrow pore distribution centered at 2.7 nm, and pore volume of 0.24 cm(3) g(-1), was obtained. We discover that amide carboxyl groups of yeast play an important role in the chemical interaction between protein molecules and zirconium phosphate nanoparticles. Interestingly, an air electrode fabricated using mesoporous zirconium phosphate exhibits remarkable electrocatalytic activity for oxygen reduction reaction (ORR), compared to that of the electrolytic manganese dioxide (EMD) air electrode employed commercially, which has important applications in fuel cell technologies. PMID:20031146

  10. Cylodextrin Polymer Nitrate

    NASA Technical Reports Server (NTRS)

    Kosowski, Bernard; Ruebner, Anja; Statton, Gary; Robitelle, Danielle; Meyers, Curtis

    2000-01-01

    The development of the use of cyclodextrin nitrates as possible components of insensitive, high-energy energetics is outlined over a time period of 12 years. Four different types of cyclodextrin polymers were synthesized, nitrated, and evaluated regarding their potential use for the military and aerospace community. The synthesis of these novel cyclodextrin polymers and different nitration techniques are shown and the potential of these new materials is discussed.

  11. Thermochemical nitrate destruction

    DOEpatents

    Cox, John L. (Richland, WA); Hallen, Richard T. (Richland, WA); Lilga, Michael A. (Richland, WA)

    1992-01-01

    A method is disclosed for denitrification of nitrates and nitrates present in aqueous waste streams. The method comprises the steps of (1) identifying the concentration nitrates and nitrites present in a waste stream, (2) causing formate to be present in the waste stream, (3) heating the mixture to a predetermined reaction temperature from about 200.degree. C. to about 600.degree. C., and (4) holding the mixture and accumulating products at heated and pressurized conditions for a residence time, thereby resulting in nitrogen and carbon dioxide gas, and hydroxides, and reducing the level of nitrates and nitrites to below drinking water standards.

  12. Production of nuclear grade zirconium: A review

    NASA Astrophysics Data System (ADS)

    Xu, L.; Xiao, Y.; van Sandwijk, A.; Xu, Q.; Yang, Y.

    2015-11-01

    Zirconium is an ideal material for nuclear reactors due to its low absorption cross-section for thermal neutrons, whereas the typically contained hafnium with strong neutron-absorption is very harmful for zirconium as a fuel cladding material. This paper provides an overview of the processes for nuclear grade zirconium production with emphasis on the methods of Zr-Hf separation. The separation processes are roughly classified into hydro- and pyrometallurgical routes. The known pyrometallurgical Zr-Hf separation methods are discussed based on the following reaction features: redox characteristics, volatility, electrochemical properties and molten salt-metal equilibrium. In the present paper, the available Zr-Hf separation technologies are compared. The advantages and disadvantages as well as future directions of research and development for nuclear grade zirconium production are discussed.

  13. Methods to treat pyrophoric film on zirconium

    SciTech Connect

    Yau, T.L.

    1982-09-01

    Zirconium is a reactive but corrosion resistant metal. However, in a highly oxidizing or an oxygen deficient solution, corrosion of zirconium can be rapid and a pyrophoric film, which ignites easily, may be formed on the surface of zirconium. Although high corrosion rates only infrequently lead to the formation of pyrophoric films, great care should be exercised with testing coupons or equipment where rapid attack is suspected. Laboratory tests were conducted to find methods to treat pyrophoric films on zirconium. Burnable specimens were prepared by placing zirconium coupons in 77.5% sulfuric acid (H/sub 2/SO/sub 4/) with 200-ppm Fe/sup +3/ (as ferric sulfate) at 80/sup 0/C for 10 days withou stirring or agitation. Chemical, X-ray diffraction, and metallographic analyses indicate that the pyrophoric film is composed of ..gamma..-hydride, zirconium oxide, zirconium sulfate, and metallic particles. This pyrophoric film could not be removed easily using common pickling solutions, that is, nitric acid-hydrofluoric acid (HNO/sub 3/-HF) mixtures, or other aggressive media, for example, 80% H/sub 2/SO/sub 4/. It has been found that the pyrophoric film can be rendered nonpyrophoric by treating with hot air or steam. A 20 to 30 min treatment with 250/sup 0/C air or steam is sufficient to completely eliminate the pyrophoric tendency. Lower temperature air or steam can be used but require longer time: a few hours if the temperature is 200/sup 0/C, and a few days if the temperature is 100/sup 0/C. Use of this treatment in the field has proven effective.

  14. ZIRCONIUM OXIDE NANOSTRUCTURES PREPARED BY ANODIC OXIDATION

    SciTech Connect

    Dang, Y. Y.; Bhuiyan, M.S.; Paranthaman, M. P.

    2008-01-01

    Zirconium oxide is an advanced ceramic material highly useful for structural and electrical applications because of its high strength, fracture toughness, chemical and thermal stability, and biocompatibility. If highly-ordered porous zirconium oxide membranes can be successfully formed, this will expand its real-world applications, such as further enhancing solid-oxide fuel cell technology. Recent studies have achieved various morphologies of porous zirconium oxide via anodization, but they have yet to create a porous layer where nanoholes are formed in a highly ordered array. In this study, electrochemical methods were used for zirconium oxide synthesis due to its advantages over other coating techniques, and because the thickness and morphology of the ceramic fi lms can be easily tuned by the electrochemical parameters, such as electrolyte solutions and processing conditions, such as pH, voltage, and duration. The effects of additional steps such as pre-annealing and post-annealing were also examined. Results demonstrate the formation of anodic porous zirconium oxide with diverse morphologies, such as sponge-like layers, porous arrays with nanoholes ranging from 40 to 75 nm, and nanotube layers. X-ray powder diffraction analysis indicates a cubic crystallographic structure in the zirconium oxide. It was noted that increased voltage improved the ability of the membrane to stay adhered to the zirconium substrate, whereas lower voltages caused a propensity for the oxide fi lm to fl ake off. Further studies are needed to defi ne the parameters windows that create these morphologies and to investigate other important characteristics such as ionic conductivity.

  15. Zirconium Oxide Nanostructures Prepared by Anodic Oxidation

    SciTech Connect

    Dang, Ying Yi; Bhuiyan, Md S; Paranthaman, Mariappan Parans

    2008-01-01

    Zirconium oxide is an advanced ceramic material highly useful for structural and electrical applications because of its high strength, fracture toughness, chemical and thermal stability, and biocompatibility. If highly-ordered porous zirconium oxide membranes can be successfully formed, this will expand its real-world applications, such as further enhancing solid-oxide fuel cell technology. Recent studies have achieved various morphologies of porous zirconium oxide via anodization, but they have yet to create a porous layer where nanoholes are formed in a highly ordered array. In this study, electrochemical methods were used for zirconium oxide synthesis due to its advantages over other coating techniques, and because the thickness and morphology of the ceramic films can be easily tuned by the electrochemical parameters, such as electrolyte solutions and processing conditions, such as pH, voltage, and duration. The effects of additional steps such as pre-annealing and post-annealing were also examined. Results demonstrate the formation of anodic porous zirconium oxide with diverse morphologies, such as sponge-like layers, porous arrays with nanoholes ranging from 40 to 75 nm, and nanotube layers. X-ray powder diffraction analysis indicates a cubic crystallographic structure in the zirconium oxide. It was noted that increased voltage improved the ability of the membrane to stay adhered to the zirconium substrate, whereas lower voltages caused a propensity for the oxide film to flake off. Further studies are needed to define the parameters windows that create these morphologies and to investigate other important characteristics such as ionic conductivity.

  16. Synthesis of zirconium oxide nanoparticle by sol-gel technique

    SciTech Connect

    Lim, H. S.; Ahmad, A.; Hamzah, H.

    2013-11-27

    Zirconium oxide nanoparticle is synthesized using sol-gel technique. Various mole ratio of ammonia solution and nitric acid relative to zirconium propoxide is added in the reaction to study the effect on the crystallinity and particle size on zirconium oxide particle. Zirconium oxide synthesized with nitric acid have the smallest particle size under FESEM image and show the increasing formation of crystalline tetragonal phase under XRD diffractogram.

  17. Thermochemical nitrate destruction

    DOEpatents

    Cox, J.L.; Hallen, R.T.; Lilga, M.A.

    1992-06-02

    A method is disclosed for denitrification of nitrates and nitrites present in aqueous waste streams. The method comprises the steps of (1) identifying the concentration nitrates and nitrites present in a waste stream, (2) causing formate to be present in the waste stream, (3) heating the mixture to a predetermined reaction temperature from about 200 C to about 600 C, and (4) holding the mixture and accumulating products at heated and pressurized conditions for a residence time, thereby resulting in nitrogen and carbon dioxide gas, and hydroxides, and reducing the level of nitrates and nitrites to below drinking water standards.

  18. The Chilean nitrate deposits.

    USGS Publications Warehouse

    Ericksen, G.E.

    1983-01-01

    The nitrate deposits in the arid Atacama desert of northern Chile consist of saline-cemented surficial material, apparently formed in and near a playa lake that formerly covered the area. Many features of their distribution and chemical composition are unique. The author believes the principal sources of the saline constituents were the volcanic rocks of late Tertiary and Quaternary age in the Andes and that the nitrate is of organic origin. Possible sources of the nitrate, iodate, perchlorate and chromate are discussed. -J.J.Robertson

  19. Capture of Phosphopeptides Using r-Zirconium Phosphate Nanoplatelets

    E-print Network

    Zare, Richard N.

    Capture of Phosphopeptides Using r-Zirconium Phosphate Nanoplatelets Songyun Xu,, John C. Whitin, College Station, Texas 77843-3123 r-Zirconium phosphate nanoplatelets (r-ZrPN) were stud- ied as a binding agent for phosphopeptides. Nanoplatelets of r-zirconium phosphate were incubated overnight

  20. Processing fissile material mixtures containing zirconium and/or carbon

    DOEpatents

    Johnson, Michael Ernest; Maloney, Martin David

    2013-07-02

    A method of processing spent TRIZO-coated nuclear fuel may include adding fluoride to complex zirconium present in a dissolved TRIZO-coated fuel. Complexing the zirconium with fluoride may reduce or eliminate the potential for zirconium to interfere with the extraction of uranium and/or transuranics from fission materials in the spent nuclear fuel.

  1. The chemical vapor deposition of zirconium carbide onto ceramic substrates

    SciTech Connect

    Glass, John A, Jr.; Palmisiano, Nick, Jr.; Welsh, R. Edward

    1999-07-01

    Zirconium carbide is an attractive ceramic material due to its unique properties such as high melting point, good thermal conductivity, and chemical resistance. The controlled preparation of zirconium carbide films of superstoichiometric, stoichiometric, and substoichiometric compositions has been achieved utilizing zirconium tetrachloride and methane precursor gases in an atmospheric pressure high temperature chemical vapor deposition system.

  2. Review of zirconium-zircaloy pyrophoricity

    SciTech Connect

    Cooper, T.D.

    1984-11-01

    Massive zirconium metal scrap can be handled, shipped, and stored with no evidence of combustion or pyrophoricity hazards. Mechanically produced fine scrap such as shavings, turnings, or powders can burn but are not pyrophoric unless the particle diameter is less than 54 ..mu..m. Powders with particle diameters less than 54 ..mu..m can be both pyrophoric and explosive. Pyrophoric powders should be collected and stored underwater or under inert gas cover to reduce the flammability hazard. Opening sealed containers of zirconium stored underwater should be attempted with caution since hydrogen may be present. The factors that influence the ignition temperature have been explored in depth and recommendations are included for the safe handling, shipping, and storage of pyrophoric or flammable zirconium. 29 refs., 5 figs., 6 tabs.

  3. Protein tyrosine nitration

    PubMed Central

    Chaki, Mounira; Leterrier, Marina; Barroso, Juan B

    2009-01-01

    Nitric oxide metabolism in plant cells has a relative short history. Nitration is a chemical process which consists of introducing a nitro group (-NO2) into a chemical compound. in biological systems, this process has been found in different molecules such as proteins, lipids and nucleic acids that can affect its function. This mini-review offers an overview of this process with special emphasis on protein tyrosine nitration in plants and its involvement in the process of nitrosative stress. PMID:19826215

  4. Nonlinear neck formation in zirconium alloys

    NASA Astrophysics Data System (ADS)

    Poletika, T. M.; Pshenichnikov, A. P.

    2009-05-01

    The macrolocalization of plastic strain in samples of zirconium alloys with hexagonal close-packed structure under uniaxial tension was studied by laser speckle interferometry and surface profiling. The occurrence of oscillatory instability in the parabolic stage of plastic flow of zirconium alloys was found to be due to a local nonuniform change of the sample shape. The kinetics of process was shown to be determined by oscillatory changes in the contraction and elongation strains at the macrolocalization site in the hardening-softening regime.

  5. Cloning and nitrate induction of nitrate reductase mRNA

    PubMed Central

    Cheng, Chi-Lien; Dewdney, Julia; Kleinhofs, Andris; Goodman, Howard M.

    1986-01-01

    Nitrate is the major source of nitrogen taken from the soil by higher plants but requires reduction to ammonia prior to incorporation into amino acids. The first enzyme in the reducing pathway is a nitrate-inducible enzyme, nitrate reductase (EC 1.6.6.1). A specific polyclonal antiserum raised against purified barley nitrate reductase has been used to immunoprecipitate in vivo labeled protein and in vitro translation products, demonstrating that nitrate induction increases nitrate reductase protein and translatable mRNA. A partial cDNA clone for barley nitrate reductase has been isolated and identified by hybrid-selected translation. RNA blot-hybridization analysis shows that nitrate induction also causes a marked increase in the steady-state level of nitrate reductase mRNA. Images PMID:16593758

  6. Superconductivity in zirconium-rhodium alloys

    NASA Technical Reports Server (NTRS)

    Zegler, S. T.

    1969-01-01

    Metallographic studies and transition temperature measurements were made with isothermally annealed and water-quenched zirconium-rhodium alloys. The results clarify both the solid-state phase relations at the Zr-rich end of the Zr-Rh alloy system and the influence upon the superconducting transition temperature of structure and composition.

  7. 21 CFR 181.33 - Sodium nitrate and potassium nitrate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrate and potassium nitrate. 181.33 Section 181.33 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) PRIOR-SANCTIONED FOOD INGREDIENTS Specific Prior-Sanctioned Food Ingredients § 181.33 Sodium nitrate...

  8. 40 CFR 721.10089 - Modified salicylic acid, zirconium complex (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Modified salicylic acid, zirconium complex (generic...Substances § 721.10089 Modified salicylic acid, zirconium complex (generic...identified generically as modified salicylic acid, zirconium complex (PMN...

  9. 40 CFR 721.10089 - Modified salicylic acid, zirconium complex (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Modified salicylic acid, zirconium complex (generic...Substances § 721.10089 Modified salicylic acid, zirconium complex (generic...identified generically as modified salicylic acid, zirconium complex (PMN...

  10. 40 CFR 721.10089 - Modified salicylic acid, zirconium complex (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Modified salicylic acid, zirconium complex (generic...Substances § 721.10089 Modified salicylic acid, zirconium complex (generic...identified generically as modified salicylic acid, zirconium complex (PMN...

  11. 40 CFR 721.10089 - Modified salicylic acid, zirconium complex (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Modified salicylic acid, zirconium complex (generic...Substances § 721.10089 Modified salicylic acid, zirconium complex (generic...identified generically as modified salicylic acid, zirconium complex (PMN...

  12. 40 CFR 721.10089 - Modified salicylic acid, zirconium complex (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Modified salicylic acid, zirconium complex (generic...Substances § 721.10089 Modified salicylic acid, zirconium complex (generic...identified generically as modified salicylic acid, zirconium complex (PMN...

  13. CHARACTERISTICS Nitrated compounds constitute a

    E-print Network

    Sniadecki, Nathan J.

    CHARACTERISTICS Nitrated compounds constitute a class of chemical substances that can be explosive. The appearance of nitrated compounds may vary from a fine moist crystalline solid to clear viscous liquids. A few nitrated compounds can become shock sensitive or can react with certain metals to form extremely unstable

  14. Intercalation chemistry of zirconium 4-sulfophenylphosphonate

    NASA Astrophysics Data System (ADS)

    Svoboda, Jan; Zima, Vít?zslav; Melánová, Klára; Beneš, Ludvík; Trchová, Miroslava

    2013-12-01

    Zirconium 4-sulfophenylphosphonate is a layered material which can be employed as a host for the intercalation reactions with basic molecules. A wide range of organic compounds were chosen to represent intercalation ability of zirconium 4-sulfophenylphosphonate. These were a series of alkylamines from methylamine to dodecylamine, 1,4-phenylenediamine, p-toluidine, 1,8-diaminonaphthalene, 1-aminopyrene, imidazole, pyridine, 4,4?-bipyridine, poly(ethylene imine), and a series of amino acids from glycine to 6-aminocaproic acid. The prepared compounds were characterized by powder X-ray diffraction, thermogravimetry analysis and IR spectroscopy and probable arrangement of the guest molecules in the interlayer space of the host is proposed based on the interlayer distance of the prepared intercalates and amount of the intercalated guest molecules.

  15. Manufacturing process to reduce large grain growth in zirconium alloys

    DOEpatents

    Rosecrans, P.M.

    1984-08-01

    It is an object of the present invention to provide a procedure for desensitizing zirconium-based alloys to large grain growth (LGG) during thermal treatment above the recrystallization temperature of the alloy. It is a further object of the present invention to provide a method for treating zirconium-based alloys which have been cold-worked in the range of 2 to 8% strain to reduce large grain growth. It is another object of the present invention to provide a method for fabricating a zirconium alloy clad nuclear fuel element wherein the zirconium clad is resistant to large grain growth.

  16. Walljet Electrochemistry: Quantifying Molecular Transport through Metallopolymeric and Zirconium

    E-print Network

    Walljet Electrochemistry: Quantifying Molecular Transport through Metallopolymeric and Zirconium electrochemistry to the study of molecular transport through model metallopolymeric films on indium tin oxide

  17. 33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126.28 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) WATERFRONT FACILITIES HANDLING OF DANGEROUS CARGO...

  18. High temperature behavior of zirconium germanates

    SciTech Connect

    Utkin, A.V.; Baklanova, N.I.; Vasilyeva, I.G.

    2013-05-01

    The high temperature behavior of zirconium germanates ZrGeO? and Zr?GeO? up to 2300 °C has been studied using the original photoemission thermal analysis technique with the comprehensive physicochemical study of solid and gaseous intermediate and final products. The two-stage process of incongruent sublimation of GeO? was established and the phase boundary of the homogeneity range for ZrGeO? and Zr?GeO? were deduced from the thermal analysis, X-ray diffraction and Raman spectroscopy studies. A high tendency to sintering of the final ZrO? product is discussed. - Graphical abstract: The decomposition of zirconium germanates leads to the formation of gaseous GeO? and solid sintered ZrO? and occurs via two stages with the formation of intermediate ZrO?-rich solid solution. Highlights: •Thermal behavior of ZrGeO? and Zr?GeO? was studied using the original thermal analysis technique in wide temperature range. •The decomposition occurs via two stages with the formation of intermediate ZrO?-rich solid solution. •The decomposition of zirconium germanates leads to the formation of gaseous GeO? and solid sintered ZrO?. •The temperature of decomposition is strongly depended on the total gas pressure.

  19. Neutronographic Texture Analysis of Zirconium Based Alloys

    NASA Astrophysics Data System (ADS)

    Kruželová, M.; Vratislav, S.; Kalvoda, L.; Dlouhá, M.

    2012-02-01

    Neutron diffraction is a very powerful tool in texture analysis of zirconium based alloys used in nuclear technique. Textures of five samples (two rolled sheets and three tubes) were investigated by using basal pole figures, inversion pole figures, and ODF distribution function. The texture measurement was performed at diffractometer KSN2 on the Laboratory of Neutron Diffraction, Department of Solid State Engineering, Faculty of Nuclear Sciences and Physical Engineering, CTU in Prague. Procedures for studying textures with thermal neutrons and procedures for obtaining texture parameters (direct and inverse pole figures, three dimensional orientation distribution function) are also described. Observed data were processed by software packages HEXAL and GSAS. Our results can be summarized as follows: i) All samples of zirconium alloys show the distribution of middle area into two maxima in basal pole figures. This is caused by alloying elements. A characteristic split of the basal pole maxima tilted from the normal direction toward the transverse direction can be observed for all samples, ii) Sheet samples prefer orientation of planes (100) and (110) perpendicular to rolling direction and orientation of planes (002) perpendicular to normal direction, iii) Basal planes of tubes are oriented parallel to tube axis, meanwhile (100) planes are oriented perpendicular to tube axis. Level of resulting texture and maxima position is different for tubes and for sheets. The obtained results are characteristic for zirconium based alloys.

  20. Purification of alkali metal nitrates

    DOEpatents

    Fiorucci, Louis C. (Hamden, CT); Gregory, Kevin M. (Woodridge, IL)

    1985-05-14

    A process is disclosed for removing heavy metal contaminants from impure alkali metal nitrates containing them. The process comprises mixing the impure nitrates with sufficient water to form a concentrated aqueous solution of the impure nitrates, adjusting the pH of the resulting solution to within the range of between about 2 and about 7, adding sufficient reducing agent to react with heavy metal contaminants within said solution, adjusting the pH of the solution containing reducing agent to effect precipitation of heavy metal impurities and separating the solid impurities from the resulting purified aqueous solution of alkali metal nitrates. The resulting purified solution of alkali metal nitrates may be heated to evaporate water therefrom to produce purified molten alkali metal nitrate suitable for use as a heat transfer medium. If desired, the purified molten form may be granulated and cooled to form discrete solid particles of alkali metal nitrates.

  1. Nitrate Storage and Dissimilatory Nitrate Reduction by Eukaryotic Microbes

    PubMed Central

    Kamp, Anja; Høgslund, Signe; Risgaard-Petersen, Nils; Stief, Peter

    2015-01-01

    The microbial nitrogen cycle is one of the most complex and environmentally important element cycles on Earth and has long been thought to be mediated exclusively by prokaryotic microbes. Rather recently, it was discovered that certain eukaryotic microbes are able to store nitrate intracellularly and use it for dissimilatory nitrate reduction in the absence of oxygen. The paradigm shift that this entailed is ecologically significant because the eukaryotes in question comprise global players like diatoms, foraminifers, and fungi. This review article provides an unprecedented overview of nitrate storage and dissimilatory nitrate reduction by diverse marine eukaryotes placed into an eco-physiological context. The advantage of intracellular nitrate storage for anaerobic energy conservation in oxygen-depleted habitats is explained and the life style enabled by this metabolic trait is described. A first compilation of intracellular nitrate inventories in various marine sediments is presented, indicating that intracellular nitrate pools vastly exceed porewater nitrate pools. The relative contribution by foraminifers to total sedimentary denitrification is estimated for different marine settings, suggesting that eukaryotes may rival prokaryotes in terms of dissimilatory nitrate reduction. Finally, this review article sketches some evolutionary perspectives of eukaryotic nitrate metabolism and identifies open questions that need to be addressed in future investigations.

  2. Some History of Nitrates

    NASA Astrophysics Data System (ADS)

    Barnum, Dennis W.

    2003-12-01

    The history of saltpeter is an interesting combination of chemistry, world trade, technology, politics, and warfare. Originally it was obtained from the dirt floors of stables, sheep pens, pigeon houses, caverns, and even peasants' cottages; any place manure and refuse accumulated in soil under dry conditions. When these sources became inadequate to meet demand it was manufactured on saltpeter plantations, located in dry climates, where piles of dirt, limestone, and manure were allowed to stand for three to five years while soil microbes oxidized the nitrogen to nitrate—an example of early bioengineering. Extensive deposits of sodium nitrate were mined in the Atacama Desert in northern Chile from 1830 until the mid 1920s when the mines were displaced by the Haber Ostwald process.

  3. Ammonium nitrate explosive systems

    DOEpatents

    Stinecipher, Mary M. (Los Alamos, NM); Coburn, Michael D. (Los Alamos, NM)

    1981-01-01

    Novel explosives which comprise mixtures of ammonium nitrate and an ammonium salt of a nitroazole in desired ratios are disclosed. A preferred nitroazole is 3,5-dinitro-1,2,4-triazole. The explosive and physical properties of these explosives may readily be varied by the addition of other explosives and oxidizers. Certain of these mixtures have been found to act as ideal explosives.

  4. COMPARISON OF MUTAGENIC ACTIVITIES OF SEVERAL PEROXYACL NITRATES

    EPA Science Inventory

    Salmonella typhimurium, strain TA100 was exposed to a series of peroxyacyl nitrates including peroxyacetyl nitrate (PAN), peroxypropionyl nitrate (PPN), peroxybutyryl nitrate (PBN), peroxybenzoyl nitrate (PBzN), and chloroperoxyacetyl nitrate (CPAN). as-phase concentrations for t...

  5. COMPARISON OF MUTAGENIC ACTIVITIES OF SEVERAL PEROXYACYL NITRATES

    EPA Science Inventory

    Salmonella typhimurium strain TA100 was exposed to a series of peroxyacyl nitrates including peroxyacetyl nitrate (PAN), peroxypropionyl nitrate peroxybutyryl nitrate (PBN), peroxybenzoyl nitrate (PBzN), and chlororoxyacetyl nitrate (CPAN). as phase concentrations for the individ...

  6. Process of precipitating zirconium or hafnium from spent pickling solutions

    SciTech Connect

    Aguilar, C.L.; Walker, R.G.

    1991-12-31

    This patent describes a process for regenerating a spent, fluoride-containing pickle solution used in the pickling of zirconium or hafnium metal or their alloys. It comprises adding to the spent pickle solution a sufficient amount of sodium sulfate to precipitate sodium zirconium or hafnium fluoride.

  7. 40 CFR 721.10601 - Lanthanum lead titanium zirconium oxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Lanthanum lead titanium zirconium... Specific Chemical Substances § 721.10601 Lanthanum lead titanium zirconium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as lanthanum...

  8. 40 CFR 721.10602 - Lead niobium titanium zirconium oxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Lead niobium titanium zirconium oxide... Specific Chemical Substances § 721.10602 Lead niobium titanium zirconium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as lead niobium...

  9. 40 CFR 721.10601 - Lanthanum lead titanium zirconium oxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Lanthanum lead titanium zirconium... Specific Chemical Substances § 721.10601 Lanthanum lead titanium zirconium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as lanthanum...

  10. 40 CFR 721.10602 - Lead niobium titanium zirconium oxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Lead niobium titanium zirconium oxide... Specific Chemical Substances § 721.10602 Lead niobium titanium zirconium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as lead niobium...

  11. 40 CFR 721.10598 - Lead strontium titanium zirconium oxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Lead strontium titanium zirconium... Specific Chemical Substances § 721.10598 Lead strontium titanium zirconium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as lead...

  12. 40 CFR 721.10598 - Lead strontium titanium zirconium oxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Lead strontium titanium zirconium... Specific Chemical Substances § 721.10598 Lead strontium titanium zirconium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as lead...

  13. Mechanism for zirconium oxide atomic layer deposition using bis,,methylcyclopentadienyl...methoxymethyl zirconium

    E-print Network

    Mechanism for zirconium oxide atomic layer deposition using bis.1063/1.2824814 Atomic layer deposition ALD is a thin film growth method using alternating, self-limiting reactions between gaseous precursors and a solid surface to deposit materials in an atomic layer-by-layer fashion.1

  14. Assimilation of nitrate by yeasts.

    PubMed

    Siverio, José M

    2002-08-01

    Nitrate assimilation has received much attention in filamentous fungi and plants but not so much in yeasts. Recently the availability of classical genetic and molecular biology tools for the yeast Hansenula polymorpha has allowed the advance of the study of this metabolic pathway in yeasts. The genes YNT1, YNR1 and YNI1, encoding respectively nitrate transport, nitrate reductase and nitrite reductase, have been cloned, as well as two other genes encoding transcriptional regulatory factors. All these genes lie closely together in a cluster. Transcriptional regulation is the main regulatory mechanism that controls the levels of the enzymes involved in nitrate metabolism although other mechanisms may also be operative. The process involved in the sensing and signalling of the presence of nitrate in the medium is not well understood. In this article the current state of the studies of nitrate assimilation in yeasts as well as possible venues for future research are reviewed. PMID:12165428

  15. Swift heavy ion irradiation of zirconium phosphate of various forms

    NASA Astrophysics Data System (ADS)

    Szirtes, L.; Megyeri, J.; Kuzmann, E.; Havancsák, K.

    2003-06-01

    The zirconium phosphate and its various derivatives have good resistance against ionization radiation, as it was found earlier during the irradiation of them with ?-rays of high energy. Continuing these experiments amorphous and crystalline (both ?- and ?-forms) zirconium phosphate, its monosodium, and propylamine intercalated forms were irradiated with a fluence of 10 11-10 14 ion cm -2 with swift heavy ions of 203Bi and 84Kr. The irradiation was also performed with Si containing zirconium phosphate. The structure of the materials was characterized by XRD method. The comparison of the powder diffraction patterns reveals that the irradiation has practically no effect on the ?-zirconium phosphate, while the other materials more or less destroyed and some of them became amorphous. The propylamine intercalate form of zirconium phosphate is decomposed on ?-ZrP and organic radical.

  16. Zirconium fluoride glass - Surface crystals formed by reaction with water

    NASA Technical Reports Server (NTRS)

    Doremus, R. H.; Bansal, N. P.; Bradner, T.; Murphy, D.

    1984-01-01

    The hydrated surfaces of a zirconium barium fluoride glass, which has potential for application in optical fibers and other optical elements, were observed by scanning electron microscopy. Crystalline zirconium fluoride was identified by analysis of X-ray diffraction patterns of the surface crystals and found to be the main constituent of the surface material. It was also found that hydrated zirconium fluorides form only in highly acidic fluoride solutions. It is possible that the zirconium fluoride crystals form directly on the glass surface as a result of its depletion of other ions. The solubility of zirconium fluoride is suggested to be probably much lower than that of barium fluoride (0.16 g/100 cu cm at 18 C). Dissolution was determined to be the predominant process in the initial stages of the reaction of the glass with water. Penetration of water into the glass has little effect.

  17. Shell model description of zirconium isotopes

    SciTech Connect

    Sieja, K.; Nowacki, F.; Langanke, K.; Martinez-Pinedo, G.

    2009-06-15

    We calculate the low-lying spectra and several high-spin states of zirconium isotopes (Z=40) with neutron numbers from N=50 to N=58 using a large valence space with the {sup 78}Ni inert core, which a priori allows one to study the interplay between spherical and deformed configurations, necessary for the description of nuclides in this part of the nuclear chart. The effective interaction is derived by monopole corrections of the realistic G matrix. We reproduce essential nuclear properties, such as subshell closures in {sup 96}Zr and {sup 98}Zr. The spherical-to-deformed shape transition in {sup 100}Zr is addressed as well.

  18. Diffusion of hydrogen in zirconium foil

    SciTech Connect

    Schur, D.V.; Pishuk, V.K.; Adejev, V.M.; Zaginaichenko, S.Y.

    1998-12-31

    The authors of present research have used in experiments the atomic hydrogen and metallic foil 25--30 {micro}m thick. It has been supposed that these technical operations will permit excluding the influence of surface and diffusional processes on the rate of Me-H interaction. The series of experiments have been carried out and they confirm this assumption. It has been shown that hydrogenation reaction of zirconium foil in atomic hydrogen conforms to the topochemical model of volume segregation of interaction product, and the rate of its flow is independent of the surface processes and hydrogen diffusion in volume.

  19. The irradiation effects on zirconium alloys

    NASA Astrophysics Data System (ADS)

    Negut, Gh.; Ancuta, M.; Radu, V.; Ionescu, S.; Stefan, V.; Uta, O.; Prisecaru, I.; Danila, N.

    2007-05-01

    Pressure tube samples were irradiated under helium atmosphere in the TRIGA Steady State Research and Material Test Reactor of the Romanian Institute for Nuclear Research (INR). These samples are made of the Zr-2.5%Nb alloy used as structural material for the CANDU Romanian power reactors. After irradiation, mechanical tests were performed in the Post Irradiation Examination Laboratory (PIEL) to study the influence of irradiation on zirconium alloys mechanical behaviour. The tensile test results were used for structural integrity assessment. Results of the tests are presented. The paper presents, also, pressure tube structural integrity assessment.

  20. Cherenkov and Scintillation Properties of Cubic Zirconium

    NASA Technical Reports Server (NTRS)

    Christl, M.J.; Adams, J.H.; Parnell, T.A.; Kuznetsov, E.N.

    2008-01-01

    Cubic zirconium (CZ) is a high index of refraction (n =2.17) material that we have investigated for Cherenkov counter applications. Laboratory and proton accelerator tests of an 18cc sample of CZ show that the expected fast Cherenkov response is accompanied by a longer scintillation component that can be separated by pulse shaping. This presents the possibility of novel particle spectrometers which exploits both properties of CZ. Other high index materials being examined for Cherenkov applications will be discussed. Results from laboratory tests and an accelerator exposure will be presented and a potential application in solar energetic particle instruments will be discussed

  1. dl-Asparaginium nitrate

    PubMed Central

    Moussa Slimane, Nabila; Cherouana, Aouatef; Bendjeddou, Lamia; Dahaoui, Slimane; Lecomte, Claude

    2009-01-01

    In the title compound, C4H9N2O3 +·NO3 ?, alternatively called (1RS)-2-carbamoyl-1-carboxy­ethanaminium nitrate, the asymmetric unit comprises one asparaginium cation and one nitrate anion. The strongest cation–cation O—H?O hydrogen bond in the structure, together with other strong cation–cation N—H?O hydrogen bonds, generates a succession of infinite chains of R 2 2(8) rings along the b axis. Additional cation–cation C—H?O hydrogen bonds link these chains into two-dimensional layers formed by alternating R 4 4(24) and R 4 2(12) rings. Connections between these layers are provided by the strong cation–anion N—H?O hydrogen bonds, as well as by one weak C—H?O inter­action, thus forming a three-dimensional network. Some of the cation–anion N—H?O hydrogen bonds are bifurcated of the type D—H?(A 1,A 2). PMID:21577586

  2. 21 CFR 172.160 - Potassium nitrate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 2011-04-01 2011-04-01 false Potassium nitrate. 172.160 Section 172.160...CONSUMPTION Food Preservatives § 172.160 Potassium nitrate. The food additive potassium nitrate may be safely used as a curing...

  3. 21 CFR 172.160 - Potassium nitrate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 2012-04-01 2012-04-01 false Potassium nitrate. 172.160 Section 172.160...CONSUMPTION Food Preservatives § 172.160 Potassium nitrate. The food additive potassium nitrate may be safely used as a curing...

  4. 21 CFR 172.160 - Potassium nitrate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 2014-04-01 2014-04-01 false Potassium nitrate. 172.160 Section 172.160...CONSUMPTION Food Preservatives § 172.160 Potassium nitrate. The food additive potassium nitrate may be safely used as a curing...

  5. 21 CFR 172.160 - Potassium nitrate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 2010-04-01 2009-04-01 true Potassium nitrate. 172.160 Section 172.160...CONSUMPTION Food Preservatives § 172.160 Potassium nitrate. The food additive potassium nitrate may be safely used as a curing...

  6. 21 CFR 172.160 - Potassium nitrate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 2013-04-01 2013-04-01 false Potassium nitrate. 172.160 Section 172.160...CONSUMPTION Food Preservatives § 172.160 Potassium nitrate. The food additive potassium nitrate may be safely used as a curing...

  7. 76 FR 11273 - Ammonium Nitrate From Russia

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-01

    ...Second Review)] Ammonium Nitrate From Russia AGENCY: United States International Trade...investigation on ammonium nitrate from Russia...investigation on ammonium nitrate from Russia would be likely to lead to...

  8. 76 FR 47238 - Ammonium Nitrate From Russia

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-04

    ...Second Review] Ammonium Nitrate From Russia Determination On the basis of the record...antidumping duty order on ammonium nitrate from Russia would be likely to lead to continuation...2011), entitled Ammonium Nitrate from Russia: Investigation No....

  9. 76 FR 70366 - Ammonium Nitrate Security Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-14

    ...DHS-2008-0076] RIN 1601-AA52 Ammonium Nitrate Security Program AGENCY: National Protection...rulemaking (NPRM), entitled ``Ammonium Nitrate Security Program,'' which was published...62311). Under the proposed Ammonium Nitrate Security Program, the DHS will...

  10. Retrospective Reactor Dosimetry with Zirconium Alloy Samples

    SciTech Connect

    Greenwood, Lawrence R.; Foster, John P.

    2009-11-01

    Retrospective measurements are routinely performed with stainless steel samples. Recent experiments have been successfully conducted using zirconium alloy samples, involving somewhat different neuron activation reactions than are normally encountered with stainless steel samples. The alloy composition consisted of nominally 1% (by weight) niobium, 1% tin, and 0.1% iron, with the balance zirconium. The activation products observed in the samples by gamma spectroscopy included Zr-95, Nb-95, Sn-113, Sb-125, Mn-54, Co-60, Nb-94, and Ta-182. The niobium was then chemically separated following ASTM procedure E1297 and the Nb-93m activities were measured by x-ray spectroscopy. The thermal neutron fluences, as determined independently by the neutron capture gamma reactions to Zr-95, Sn-113, Nb-94, and Sn/Sb-125, were in excellent agreement. The fast neutron fluences, as determined separately by the Fe-54(n,p)Mn-54 and Nb-93(n,n’)Nb-93m reactions, were also in good agreement, thus demonstrating the versatility of the retrospective dosimetry technique.

  11. Diffusion of insoluble carbon in zirconium oxides

    NASA Astrophysics Data System (ADS)

    Vykhodets, V. B.; Kurennykh, T. E.; Kesarev, A. G.; Kuznetsov, M. V.; Kondrat'ev, V. V.; Hülsen, C.; Koester, U.

    2011-03-01

    The diffusion coefficient of insoluble carbon in zirconium oxides has been obtained for the temperature range of 900-1000°C. There are no published data on the diffusion of insoluble impurities; these data are of current interest for the diffusion theory and nuclear technologies. Tracer atoms 13C have been introduced into oxides by means of ion implantation and the kinetics of their emission from the samples in the process of annealing in air has been analyzed. The measurements have been performed using the methods of nuclear microanalysis and X-ray photoelectron spectroscopy. The diffusion activation energy is 2.7 eV and the carbon diffusion coefficient is about six orders of magnitude smaller than that for oxygen self-diffusion in the same systems. This result indicates the strong anomaly of the diffusion properties of carbon in oxides. As a result, zirconium oxides cannot be used in some nuclear technologies, in particular, as a material of sources for accelerators of short-lived carbon isotopes.

  12. Nitrate | Cancer Trends Progress Report

    Cancer.gov

    Nitrates and nitrites are nitrogen-oxygen chemical units that naturally occur in soil, water, and some foods. When taken into the body by drinking water and through other dietary sources, nitrate and nitrite can react with amines and amides to form N-nitroso compounds (NOC), which are known to cause cancer in animals and may cause cancer in humans.

  13. Protein nitration by polluted air.

    PubMed

    Franze, Thomas; Weller, Michael G; Niessner, Reinhard; Pöschl, Ulrich

    2005-03-15

    The effects of air pollution on allergic diseases are not yetwell-understood. Here, we show that proteins, in particular birch pollen proteins including the allergen Bet v 1, are efficiently nitrated by polluted air. This posttranslational modification of proteins is likely to trigger immune reactions and provides a molecular rationale for the promotion of allergies bytraffic-related air pollution. Enzyme immunoassays have been used to determine equivalent degrees of nitration (EDN) for protein samples exposed to urban outdoor air and synthetic gas mixtures. The observed rates of nitration were governed by the abundance of nitrogen oxides and ozone, and concentration levels typical for summer smog conditions led to substantial nitration within a few hours to days (EDN up to 20%). Moreover, nitrated proteins were detected in urban road dust, window dust, and fine air particulate matter (EDN up to 0.1%). PMID:15819224

  14. Amine-intercalated ?-zirconium phosphates as lubricant additives

    NASA Astrophysics Data System (ADS)

    Xiao, Huaping; Dai, Wei; Kan, Yuwei; Clearfield, Abraham; Liang, Hong

    2015-02-01

    In this study, three types of amines intercalated ?-zirconium phosphate nanosheets with different interspaces were synthesized and examined as lubricant additives to a mineral oil. Results from tribological experiments illustrated that these additives improved lubricating performance. Results of rheological experiments showed that the viscosity of the mineral oil was effectively reduced with the addition of ?-zirconium phosphate nanosheets. The two-dimensional structure, with larger interspaces, resulting from amine intercalation, exhibited improved effectiveness in reducing viscosity. This study demonstrates that the nanosheet structure of ?-zirconium phosphates is effective in friction reduction. The manufacture of lubricants with tailored viscosity is possible by using different intercalators.

  15. Ballistic effectiveness of superdense solid composite propellants with zirconium or zirconium hydride

    NASA Astrophysics Data System (ADS)

    Lempert, D.; Manelis, G.; Nechiporenko, G.

    2011-10-01

    The ballistic effectiveness of propellants depends not only on the value of specific impulse but also on many other performances, primarily on the density. Despite the density itself does not enter the expression of the rocket velocity (W = Isp ln(Mlaunch/Mfinish) where Mlaunch and Mfinish are the rocket launch mass and its mass after the propellant is burnt, respectively), it in§uences the value Mlaunch/Mfinish of the specific rocket. If one charges the construction of fixed volume with a more dense propellant, the ratio Mlaunch/Mfinish increases and, consequently, W increases as well. In this paper, the possibility of creating solid composite propellants (SCP) with zirconium (density 6.49 g/cm3) and zirconium hydride (density 5.61 g/cm3 ) as energetic compounds instead of aluminum is considered. It was found for what kinds of engines these propellants have to be more effective than propellants based on aluminum.

  16. Crystal Structure of the ZrO Phase at Zirconium/Zirconium Oxide Interfaces**

    PubMed Central

    Nicholls, Rebecca J; Ni, Na; Lozano-Perez, Sergio; London, Andrew; McComb, David W; Nellist, Peter D; Grovenor, Chris RM; Pickard, Chris J; Yates, Jonathan R

    2015-01-01

    Zirconium-based alloys are used in water-cooled nuclear reactors for both nuclear fuel cladding and structural components. Under this harsh environment, the main factor limiting the service life of zirconium cladding, and hence fuel burn-up efficiency, is water corrosion. This oxidation process has recently been linked to the presence of a sub-oxide phase with well-defined composition but unknown structure at the metal–oxide interface. In this paper, the combination of first-principles materials modeling and high-resolution electron microscopy is used to identify the structure of this sub-oxide phase, bringing us a step closer to developing strategies to mitigate aqueous oxidation in Zr alloys and prolong the operational lifetime of commercial fuel cladding alloys. PMID:25892957

  17. Nitrate concentrations under irrigated agriculture

    USGS Publications Warehouse

    Zaporozec, A.

    1983-01-01

    In recent years, considerable interest has been expressed in the nitrate content of water supplies. The most notable toxic effect of nitrate is infant methemoglobinemia. The risk of this disease increases significantly at nitrate-nitrogen levels exceeding 10 mg/l. For this reason, this concentration has been established as a limit for drinking water in many countries. In natural waters, nitrate is a minor ionic constituent and seldom accounts for more than a few percent of the total anions. However, nitrate in a significant concentration may occur in the vicinity of some point sources such as septic tanks, manure pits, and waste-disposal sites. Non-point sources contributing to groundwater pollution are numerous and a majority of them are related to agricultural activities. The largest single anthropogenic input of nitrate into the groundwater is fertilizer. Even though it has not been proven that nitrogen fertilizers are responsible for much of nitrate pollution, they are generally recognized as the main threat to groundwater quality, especially when inefficiently applied to irrigated fields on sandy soils. The biggest challenge facing today's agriculture is to maintain the balance between the enhancement of crop productivity and the risk of groundwater pollution. ?? 1982 Springer-Verlag New York Inc.

  18. Electrochemical study of corrosion phenomena in zirconium alloys

    E-print Network

    Treeman, Nicole M

    2005-01-01

    Shadow corrosion of zirconium alloy fuel cladding in BWR environments, the phenomenon in which accelerated corrosion is experienced when the cladding surface is in close proximity to other metals, has become a potentially ...

  19. Investigation of Electrochemical Recovery of Zirconium from Spent Nuclear Fuels

    SciTech Connect

    Michael Simpson; II-Soon Hwang

    2014-06-01

    This project uses both modeling and experimental studies to design optimal electrochemical technology methods for recovery of zirconium from used nuclear fuel rods for more effective waste management. The objectives are to provide a means of efficiently separating zirconium into metallic high-level waste forms and to support development of a process for decontamination of zircaloy hulls to enable their disposal as low- and intermediate-level waste. Modeling work includes extension of a 3D model previously developed by Seoul National University for uranium electrorefining by adding the ability to predict zirconium behavior. Experimental validation activities include tests for recovery of zirconium from molten salt solutions and aqueous tests using surrogate materials. *This is a summary of the FY 2013 progress for I-NERI project # 2010-001-K provided to the I-NERI office.

  20. Nucleation Pathways For Freezing Of Two Grades Of Zirconium

    NASA Technical Reports Server (NTRS)

    Rhim, Won-Kyu; Rulison, Aaron; Bayuzick, Robert; Hofmeister, William; Morton, Craig

    1996-01-01

    Report discusses classical nucleation theory of freezing and describes experimental study of nucleation mechanisms that predominate during freezing of spherical specimens of initially molten zirconium levitated electrostatically in vacuum.

  1. Fabrication and Characterization of Uranium-Molybdenum-Zirconium Alloys 

    E-print Network

    Woolum, Connor

    2014-12-12

    As part of a global effort to convert reactors that require highly enriched uranium to instead operate with low enriched uranium, monolithic fuel plates consisting of a U-Mo fuel meat with a zirconium foil barrier layer ...

  2. Zirconium and hafnium with low oxygen and iron

    SciTech Connect

    Kwon, Y.J.

    1988-02-02

    A high purity zirconium sponge or hafnium sponge is described consisting of 250-about 350 ppm of oxygen impurity, 50-350 ppm of iron impurity, total impurities of 500-1,000 ppm, with the remainder being zirconium or hafnium, whereby an inexpensive intermediate product is provided which can be processed for use in applications requiring high purity material, without resorting to expensive crystal bar processing.

  3. Quercetin as colorimetric reagent for determination of zirconium

    USGS Publications Warehouse

    Grimaldi, F.S.; White, C.E.

    1953-01-01

    Methods described in the literature for the determination of zirconium are generally designed for relatively large amounts of this element. A good procedure using colorimetric reagent for the determination of trace amounts is desirable. Quercetin has been found to yield a sensitive color reaction with zirconium suitable for the determination of from 0.1 to 50?? of zirconium dioxide. The procedure developed involves the separation of zirconium from interfering elements by precipitation with p-dimethylaminoazophenylarsonic acid prior to its estimation with quercetin. The quercetin reaction is carried out in 0.5N hydrochloric acid solution. Under the operating conditions it is indicated that quercetin forms a 2 to 1 complex with zirconium; however, a 2 to 1 and a 1 to 1 complex can coexist under special conditions. Approximate values for the equilibrium constants of the complexes are K1 = 0.33 ?? 10-5 and K2 = 1.3 ?? 10-9. Seven Bureau of Standards samples of glass sands and refractories were analyzed with excellent results. The method described should find considerable application in the analysis of minerals and other materials for macro as well as micro amounts of zirconium.

  4. Nitrate and Prussic Acid Poisoning 

    E-print Network

    Stichler, Charles; Reagor, John C.

    2001-09-05

    Nitrate and prussic acid poisoning in cattle are noninfectious conditions that can kill livestock. This publication explains the causes and symptoms of these conditions as well as preventive measures and sampling and testing steps....

  5. 46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Ammonium nitrate and ammonium nitrate fertilizers. 148... Materials § 148.205 Ammonium nitrate and ammonium nitrate fertilizers. (a) This section applies to the stowage and transportation in bulk of ammonium nitrate and the following fertilizers composed of...

  6. 46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Ammonium nitrate and ammonium nitrate fertilizers. 148... Materials § 148.205 Ammonium nitrate and ammonium nitrate fertilizers. (a) This section applies to the stowage and transportation in bulk of ammonium nitrate and the following fertilizers composed of...

  7. 46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Ammonium nitrate and ammonium nitrate fertilizers. 148... Materials § 148.205 Ammonium nitrate and ammonium nitrate fertilizers. (a) This section applies to the stowage and transportation in bulk of ammonium nitrate and the following fertilizers composed of...

  8. 46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Ammonium nitrate and ammonium nitrate fertilizers. 148... Materials § 148.205 Ammonium nitrate and ammonium nitrate fertilizers. (a) This section applies to the stowage and transportation in bulk of ammonium nitrate and the following fertilizers composed of...

  9. Quantification of Nitrate Sources to an Urban Stream Using Dual Nitrate Isotopes

    E-print Network

    Elliott, Emily M.

    Quantification of Nitrate Sources to an Urban Stream Using Dual Nitrate Isotopes Marion T. Divers nitrogen, particularly in urban watersheds. In this study, we used dual-nitrate isotopes and mixing model composition of potential nitrate sources and resolved the relative proportions of nitrate inputs from each

  10. Viscosity of Molten Sodium Nitrate

    NASA Astrophysics Data System (ADS)

    Nunes, V. M. B.; Lourenço, M. J. V.; Santos, F. J. V.; de Castro, C. A. Nieto

    2006-11-01

    New experimental data for the viscosity of molten sodium nitrate from its melting point up to 752 K, at atmospheric pressure, with an estimated uncertainty of 2.1%, were measured with an oscillating cup viscometer. A preliminary reference correlation and reference data are proposed, based on the best available data for the viscosity of molten sodium nitrate, for temperatures between 590 and 750 K, with an estimated absolute uncertainty of 0.066 mPa · s ( k = 2).

  11. 40 CFR 721.10152 - Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4...Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4...oxirane, substituted silylmethyl-, hydrolysis products with alkanol...

  12. 40 CFR 721.10152 - Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4...Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4...oxirane, substituted silylmethyl-, hydrolysis products with alkanol...

  13. 40 CFR 721.10152 - Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4...Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4...oxirane, substituted silylmethyl-, hydrolysis products with alkanol...

  14. 40 CFR 721.10152 - Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4...Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4...oxirane, substituted silylmethyl-, hydrolysis products with alkanol...

  15. 40 CFR 721.10152 - Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4...Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4...oxirane, substituted silylmethyl-, hydrolysis products with alkanol...

  16. Nitrate transport is independent of NADH and NAD(P)H nitrate reductases in barley seedlings

    NASA Technical Reports Server (NTRS)

    Warner, R. L.; Huffaker, R. C.

    1989-01-01

    Barley (Hordeum vulgare L.) has NADH-specific and NAD(P)H-bispecific nitrate reductase isozymes. Four isogenic lines with different nitrate reductase isozyme combinations were used to determine the role of NADH and NAD(P)H nitrate reductases on nitrate transport and assimilation in barley seedlings. Both nitrate reductase isozymes were induced by nitrate and were required for maximum nitrate assimilation in barley seedlings. Genotypes lacking the NADH isozyme (Az12) or the NAD(P)H isozyme (Az70) assimilated 65 or 85%, respectively, as much nitrate as the wild type. Nitrate assimilation by genotype (Az12;Az70) which is deficient in both nitrate reductases, was only 13% of the wild type indicating that the NADH and NAD(P)H nitrate reductase isozymes are responsible for most of the nitrate reduction in barley seedlings. For all genotypes, nitrate assimilation rates in the dark were about 55% of the rates in light. Hypotheses that nitrate reductase has direct or indirect roles in nitrate uptake were not supported by this study. Induction of nitrate transporters and the kinetics of net nitrate uptake were the same for all four genotypes indicating that neither nitrate reductase isozyme has a direct role in nitrate uptake in barley seedlings.

  17. Understanding the Irradiation Behavior of Zirconium Carbide

    SciTech Connect

    Motta, Arthur; Sridharan, Kumar; Morgan, Dane; Szlufarska, Izabela

    2013-10-11

    Zirconium carbide (ZrC) is being considered for utilization in high-temperature gas-cooled reactor fuels in deep-burn TRISO fuel. Zirconium carbide possesses a cubic B1-type crystal structure with a high melting point, exceptional hardness, and good thermal and electrical conductivities. The use of ZrC as part of the TRISO fuel requires a thorough understanding of its irradiation response. However, the radiation effects on ZrC are still poorly understood. The majority of the existing research is focused on the radiation damage phenomena at higher temperatures (>450{degree}C) where many fundamental aspects of defect production and kinetics cannot be easily distinguished. Little is known about basic defect formation, clustering, and evolution of ZrC under irradiation, although some atomistic simulation and phenomenological studies have been performed. Such detailed information is needed to construct a model describing the microstructural evolution in fast-neutron irradiated materials that will be of great technological importance for the development of ZrC- based fuel. The goal of the proposed project is to gain fundamental understanding of the radiation-induced defect formation in zirconium carbide and irradiation response (ZrC) by using a combination of state-of-the-art experimental methods and atomistic modeling. This project will combine (1) in situ ion irradiation at a specialized facility at a national laboratory, (2) controlled temperature proton irradiation on bulk samples, and (3) atomistic modeling to gain a fundamental understanding of defect formation in ZrC. The proposed project will cover the irradiation temperatures from cryogenic temperature to as high as 800{degree}C, and dose ranges from 0.1 to 100 dpa. The examination of this wide range of temperatures and doses allows us to obtain an experimental data set that can be effectively used to exercise and benchmark the computer calculations of defect properties. Combining the examination of radiation-induced microstructures mapped spatially and temporally, microstructural evolution during post-irradiation annealing, and atomistic modeling of defect formation and transport energetics will provide new, critical understanding about property changes in ZrC. The behavior of materials under irradiation is determined by the balance between damage production, defect clustering, and lattice response. In order to predict those effects at high temperatures so targeted testing can be expanded and extrapolated beyond the known database, it is necessary to determine the defect energetics and mobilities as these control damage accumulation and annealing. In particular, low-temperature irradiations are invaluable for determining the regions of defect mobility. Computer simulation techniques are particularly useful for identifying basic defect properties, especially if closely coupled with a well-constructed and complete experimental database. The close coupling of calculation and experiment in this project will provide mutual benchmarking and allow us to glean a deeper understanding of the irradiation response of ZrC, which can then be applied to the prediction of its behavior in reactor conditions.

  18. Evaluation of zirconium-iron-rhenium alloys as surrogates for a technetium alloy waste form 

    E-print Network

    Mews, Paul Aaron

    2009-05-15

    Stainless steel – zirconium alloys were developed by the US Department of Energy Laboratories as metallic waste forms for noble metal fission products. This thesis evaluates iron–zirconium–rhenium alloys to establish a technical basis for using...

  19. Reduction of nitrate in Shewanella

    SciTech Connect

    Gao, Haichun; Yang, Zamin Koo; Barua, Sumitra; Reed, SB; Nealson, Kenneth H.; Fredrikson, JK; Tiedje, James; Zhou, Jizhong

    2009-01-01

    In the genome of Shewanella oneidensis, a napDAGHB gene cluster encoding periplasmic nitrate reductase (NapA) and accessory proteins and an nrfA gene encoding periplasmic nitrite reductase (NrfA) have been identified. These two systems seem to be atypical because the genome lacks genes encoding cytoplasmic membrane electron transport proteins, NapC for NAP and NrfBCD/NrfH for NRF, respectively. Here, we present evidence that reduction of nitrate to ammonium in S. oneidensis is carried out by these atypical systems in a two-step manner. Transcriptional and mutational analyses suggest that CymA, a cytoplasmic membrane electron transport protein, is likely to be the functional replacement of both NapC and NrfH in S. oneidensis. Surprisingly, a strain devoid of napB encoding the small subunit of nitrate reductase exhibited the maximum cell density sooner than the wild type. Further characterization of this strain showed that nitrite was not detected as a free intermediate in its culture and NapB provides a fitness gain for S. oneidensis to compete for nitrate in the environments. On the basis results from mutational analyses of napA, napB, nrfA and napBnrfA in-frame deletion mutants, we propose that NapB is able to favor nitrate reduction by routing electrons to NapA exclusively.

  20. In situ ion irradiation of zirconium carbide

    NASA Astrophysics Data System (ADS)

    Ulmer, Christopher J.; Motta, Arthur T.; Kirk, Mark A.

    2015-11-01

    Zirconium carbide (ZrC) is a candidate material for use in one of the layers of TRISO coated fuel particles to be used in the Generation IV high-temperature, gas-cooled reactor, and thus it is necessary to study the effects of radiation damage on its structure. The microstructural evolution of ZrCx under irradiation was studied in situ using the Intermediate Voltage Electron Microscope (IVEM) at Argonne National Laboratory. Samples of nominal stoichiometries ZrC0.8 and ZrC0.9 were irradiated in situ using 1 MeV Kr2+ ions at various irradiation temperatures (T = 20 K-1073 K). In situ experiments made it possible to continuously follow the evolution of the microstructure during irradiation using diffraction contrast imaging. Images and diffraction patterns were systematically recorded at selected dose points. After a threshold dose during irradiations conducted at room temperature and below, black-dot defects were observed which accumulated until saturation. Once created, the defect clusters did not move or get destroyed during irradiation so that at the final dose the low temperature microstructure consisted only of a saturation density of small defect clusters. No long-range migration of the visible defects or dynamic defect creation and elimination were observed during irradiation, but some coarsening of the microstructure with the formation of dislocation loops was observed at higher temperatures. The irradiated microstructure was found to be only weakly dependent on the stoichiometry.

  1. Experimental study on flames propagating through zirconium particle clouds.

    PubMed

    Yin, Yi; Sun, Jinhua; Ding, Yibin; Guo, Song; He, Xuechao

    2009-10-15

    To reveal the mechanisms of flame propagation through the hardly volatile metal dust clouds clearly, the flame propagating through zirconium particle clouds has been examined experimentally. A high-speed video camera was used to record the propagation process of the flame. Combustion zone temperature was detected by a fine thermocouple. Based on the experimental results, structure of flame and combustion courses of zirconium particles were analyzed, the combustion propagation in zirconium dust was investigated, and the velocity and temperature characteristics of the combustion zone were also elucidated. The combustion zone propagating through zirconium particle clouds consists of luminous particles. Particle concentration plays an important role in the combustion zone propagation process. With the increase of zirconium particle concentration, the maximum temperature of the combustion zone increases at the lower concentration, takes a maximum value, and then decreases at the higher concentration. It is also found that the propagation velocity of the combustion zone has a linear relationship with its maximum temperature. PMID:19477589

  2. Synthesis and characterization of a mesoporous hydrous zirconium oxide used for arsenic removal from drinking water

    SciTech Connect

    Bortun, Anatoly; Bortun, Mila; Pardini, James; Khainakov, Sergei A.; Garcia, Jose R.

    2010-02-15

    Powder (20-50 {mu}m) mesoporous hydrous zirconium oxide was prepared from a zirconium salt granular precursor. The effect of some process parameters on product morphology, porous structure and adsorption performance has been studied. The use of hydrous zirconium oxide for selective arsenic removal from drinking water is discussed.

  3. 40 CFR 721.10089 - Modified salicylic acid, zirconium complex (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Modified salicylic acid, zirconium... Specific Chemical Substances § 721.10089 Modified salicylic acid, zirconium complex (generic). (a) Chemical... as modified salicylic acid, zirconium complex (PMN P-00-552) is subject to reporting under...

  4. 40 CFR 721.10089 - Modified salicylic acid, zirconium complex (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Modified salicylic acid, zirconium... Specific Chemical Substances § 721.10089 Modified salicylic acid, zirconium complex (generic). (a) Chemical... as modified salicylic acid, zirconium complex (PMN P-00-552) is subject to reporting under...

  5. 40 CFR 721.10089 - Modified salicylic acid, zirconium complex (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Modified salicylic acid, zirconium... Specific Chemical Substances § 721.10089 Modified salicylic acid, zirconium complex (generic). (a) Chemical... as modified salicylic acid, zirconium complex (PMN P-00-552) is subject to reporting under...

  6. 40 CFR 721.10089 - Modified salicylic acid, zirconium complex (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Modified salicylic acid, zirconium... Specific Chemical Substances § 721.10089 Modified salicylic acid, zirconium complex (generic). (a) Chemical... as modified salicylic acid, zirconium complex (PMN P-00-552) is subject to reporting under...

  7. 40 CFR 721.10089 - Modified salicylic acid, zirconium complex (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Modified salicylic acid, zirconium... Specific Chemical Substances § 721.10089 Modified salicylic acid, zirconium complex (generic). (a) Chemical... as modified salicylic acid, zirconium complex (PMN P-00-552) is subject to reporting under...

  8. Studies on synthesis esterified zirconium glyphosates and their hydrophobic properties

    NASA Astrophysics Data System (ADS)

    Zhang, Yaqing; Li, Minglei; Ji, Xuemei; Xu, Qinghong

    2010-03-01

    A series of new organic-modified zirconium glyphosate compounds were synthesized based on the reactions between esterified glyphosates and ZrOCl 2. FT-IR spectra, solid-state 31P MAS NMR and elementary analysis proved the formation of these new compounds. Powder X-ray diffraction (PXRD) patterns and transmission electron microscope (TEM) images proved these compounds had lamellar structures. Scanning electronic microscope (SEM) images showed that solvents used in synthesis had great influence on the morphologies of products. Water contact angle measurements showed that the hydrophobic property of the products was a function of the number of carbon in esterified glyphosates, increased from 0° of zirconium glyphosate to 133° of dodecyl zirconium glyphosate. The present study offered a new route to synthesize organic-modified ?-Zr(HPO 4) 2·H 2O (?-ZrP) materials with various morphology and controllable hydrophobic property.

  9. Hydrogen pickup mechanism of zirconium alloys

    NASA Astrophysics Data System (ADS)

    Couet, Adrien

    Although the optimization of zirconium based alloys has led to significant improvements in hydrogen pickup and corrosion resistance, the mechanisms by which such alloy improvements occur are still not well understood. In an effort to understand such mechanisms, a systematic study of the alloy effect on hydrogen pickup is conducted, using advanced characterization techniques to rationalize precise measurements of hydrogen pickup. The hydrogen pick-up fraction is accurately measured for a specially designed set of commercial and model alloys to investigate the effects of alloying elements, microstructure and corrosion kinetics on hydrogen uptake. Two different techniques to measure hydrogen concentrations were used: a destructive technique, Vacuum Hot Extraction, and a non-destructive one, Cold Neutron Prompt Gamma Activation Analysis. The results indicate that hydrogen pickup varies not only from alloy to alloy but also during the corrosion process for a given alloy. For instance Zircaloy type alloys show high hydrogen pickup fraction and sub-parabolic oxidation kinetics whereas ZrNb alloys show lower hydrogen pickup fraction and close to parabolic oxidation kinetics. Hypothesis is made that hydrogen pickup result from the need to balance charge during the corrosion reaction, such that the pickup of hydrogen is directly related to (and indivisible of) the corrosion mechanism and decreases when the rate of electron transport or oxide electronic conductivity sigmao xe through the protective oxide increases. According to this hypothesis, alloying elements (either in solid solution or in precipitates) embedded in the oxide as well as space charge variations in the oxide would impact the hydrogen pick-up fraction by modifying sigmaox e, which drives oxidation and hydriding kinetics. Dedicated experiments and modelling were performed to assess and validate these hypotheses. In-situ electrochemical impedance spectroscopy (EIS) experiments were performed on Zircaloy-4 tubes to directly measure the evolution of sigma oxe as function of exposure time. The results show that sigmao xe decreases as function of exposure time and that its variations are directly correlated to the instantaneous hydrogen pickup fraction variations. The electron transport through the oxide layer is thus altered as the oxide grows, reasons for which are yet to be exactly determined. Preliminary results also show that sigma oxe of ZrNb alloys would be much higher compared with Zircaloy-4. Thus, it is confirmed that sigmaox e is a key parameter in the hydrogen and oxidation mechanism. Because the mechanism whereby alloying elements are incorporated into the oxide layer is critical to changing sigmao xe, the evolution of the oxidation state of two common alloying elements, Fe and Nb, when incorporated into the growing oxide layers is investigated using X-Ray Absorption Near-Edge Spectroscopy (XANES) using micro-beam synchrotron radiation on cross sectional oxide samples. The results show that the oxidation of both Fe and Nb is delayed in the oxide layer compared to that of Zr, and that this oxidation delay is related to the variations of the instantaneous hydrogen pick-up fraction with exposure time. The evolution of Nb oxidation as function of oxide depth is also compatible with space charge compensation in the oxide and with an increase in sigmaox e of ZrNb alloys compared to Zircaloys. Finally, various successively complex models from the well-known Wagner oxidation theory to the more complex effect of space charge on oxidation kinetics have been developed. The general purpose of the modeling effort is to provide a rationale for the sub-parabolic oxidation kinetics and demonstrate the correlation with hydrogen pickup fraction. It is directly demonstrated that parabolic oxidation kinetics is associated with high sigmao xe and low space charges in the oxide whereas sub-parabolic oxidation kinetics is associated with lower sigmaox e and higher space charge in the oxide. All these observations helped us to propose a general corrosion mechanism of zirconium allo

  10. In-situ stabilization of radioactive zirconium swarf

    SciTech Connect

    Hess, Clay C.

    1997-12-01

    The method for treating ignitable cutting swarf in accordance with the present invention involves collecting cutting swarf in a casting mold underwater and injecting a binder mixture comprising vinyl ester styrene into the vessel to fill void volume; and form a mixture comprising swarf and vinyl ester styrene; and curing the mixture. The method is especially useful for stabilizing the ignitable characteristics of radioactive zirconium cutting swarf, and can be used to solidify zirconium swarf, or other ignitable finely divided material, underwater. The process could also be performed out of water with other particulate wastes.

  11. Variant selection and transformation texture in zirconium alloy Excel

    NASA Astrophysics Data System (ADS)

    Sattari, M.; Holt, R. A.; Daymond, M. R.

    2014-10-01

    The crystallographic texture and variant selection during phase transformations in zirconium alloy Excel (Zr-3.5% Sn-0.8% Mo-0.8% Nb) was investigated. It was shown that upon water-quenching from ?Zr + ?Zr or fully ?Zr regions, variant selection occurs during ?Zr ? ??Zr martensitic transformation. Also during air-cooling from the ?Zr + ?Zr region, only a partial memory effect and some transformation texture with variant selection was observed which is contrary to previous reports on zirconium alloys heat treated in the ?Zr + ?Zr region.

  12. In-situ stabilization of radioactive zirconium swarf

    DOEpatents

    Hess, C.C.

    1999-08-31

    The method for treating ignitable cutting swarf in accordance with the present invention involves collecting cutting swarf in a casting mold underwater and injecting a binder mixture comprising vinyl ester styrene into the vessel to fill void volume; and form a mixture comprising swarf and vinyl ester styrene; and curing the mixture. The method is especially useful for stabilizing the ignitable characteristics of radioactive zirconium cutting swarf, and can be used to solidify zirconium swarf, or other ignitable finely divided material, underwater. The process could also be performed out of water with other particulate wastes. 6 figs.

  13. In-situ stabilization of radioactive zirconium swarf

    DOEpatents

    Hess, Clay C. (Idaho Falls, ID)

    1999-01-01

    The method for treating ignitable cutting swarf in accordance with the present invention involves collecting cutting swarf in a casting mold underwater and injecting a binder mixture comprising vinyl ester styrene into the vessel to fill void volume; and form a mixture comprising swarf and vinyl ester styrene; and curing the mixture. The method is especially useful for stabilizing the ignitable characteristics of radioactive zirconium cutting swarf, and can be used to solidify zirconium swarf, or other ignitable finely divided material, underwater. The process could also be performed out of water with other particulate wastes.

  14. Experiments on explosive interactions between zirconium-containing melt and water (ZREX).

    SciTech Connect

    Cho, D. H.

    1998-04-10

    The results of two series of experiments on explosive interactions between zirconium-containing melt and water are described. The first series of experiments involved dropping 1-kg batches of zirconium-zirconium dioxide mixture melt into a column of water while the second series employed 1.2-kg batches of zirconium-stainless steel mixture melt. Explosions took place only in those tests which were externally triggered. While the extent of zirconium oxidation in the triggered experiments was quite large, the explosion energies estimated from the experimental measurements were found to be small compared to the combined thermal and chemical energy available.

  15. A Novel Chemical Nitrate Destruction Process

    SciTech Connect

    Dziewinski, J.; Marczak, S.

    1999-03-01

    Nitrates represent one of the most significant pollutant discharged to the Baltic Sea by the Sliiamae hydrometallurgical plant. This article contains a brief overview of the existing nitrate destruction technologies followed by the description of a new process developed by the authors. The new chemical process for nitrate destruction is cost effective and simple to operate. It converts the nitrate to nitrogen gas which goes to the atmosphere.

  16. Nitrate reductase assay using sodium nitrate for rapid detection of multidrug resistant tuberculosis

    PubMed Central

    Macedo, Maíra Bidart; Groll, Andrea Von; Fissette, Krista; Palomino, Juan Carlos; da Silva, Pedro Eduardo Almeida; Martin, Anandi

    2012-01-01

    We validated the nitrate reductase assay (NRA) for the detection of multidrug-resistant Mycobacterium tuberculosis (MDR-TB) using sodium nitrate (NaNO3) in replacement of potassium nitrate (KNO3) as nitrate source. NaNO3 is cheaper than KNO3 and has no restriction on use which facilitates the implementation of NRA to detect MDR-TB. PMID:24031916

  17. Nitrate reductase assay using sodium nitrate for rapid detection of multidrug resistant tuberculosis.

    PubMed

    Macedo, Maíra Bidart; Groll, Andrea Von; Fissette, Krista; Palomino, Juan Carlos; da Silva, Pedro Eduardo Almeida; Martin, Anandi

    2012-07-01

    We validated the nitrate reductase assay (NRA) for the detection of multidrug-resistant Mycobacterium tuberculosis (MDR-TB) using sodium nitrate (NaNO3) in replacement of potassium nitrate (KNO3) as nitrate source. NaNO3 is cheaper than KNO3 and has no restriction on use which facilitates the implementation of NRA to detect MDR-TB. PMID:24031916

  18. Inhibition of the Soluble Epoxide Hydrolase by Tyrosine Nitration*S

    E-print Network

    Hammock, Bruce D.

    Inhibition of the Soluble Epoxide Hydrolase by Tyrosine Nitration*S Received for publication-cyclohexylurea in vitro decreased sensitivity to SIN-1. Both ONOO and SIN-1 elicited the tyrosine nitration of the sEH protein and mass spectrometry analysis of tryptic frag- ments revealed nitration on several

  19. 21 CFR 172.170 - Sodium nitrate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium nitrate. 172.170 Section 172.170 Food and... PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.170 Sodium nitrate. The food additive sodium nitrate may be safely used in or on specified foods in accordance with...

  20. 21 CFR 172.170 - Sodium nitrate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium nitrate. 172.170 Section 172.170 Food and... Preservatives § 172.170 Sodium nitrate. The food additive sodium nitrate may be safely used in or on specified... follows: (1) As a preservative and color fixative, with or without sodium nitrite, in smoked,...

  1. 21 CFR 172.170 - Sodium nitrate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium nitrate. 172.170 Section 172.170 Food and... Preservatives § 172.170 Sodium nitrate. The food additive sodium nitrate may be safely used in or on specified... follows: (1) As a preservative and color fixative, with or without sodium nitrite, in smoked,...

  2. 21 CFR 172.170 - Sodium nitrate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrate. 172.170 Section 172.170 Food and... Preservatives § 172.170 Sodium nitrate. The food additive sodium nitrate may be safely used in or on specified... follows: (1) As a preservative and color fixative, with or without sodium nitrite, in smoked,...

  3. 21 CFR 172.170 - Sodium nitrate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium nitrate. 172.170 Section 172.170 Food and... Preservatives § 172.170 Sodium nitrate. The food additive sodium nitrate may be safely used in or on specified... follows: (1) As a preservative and color fixative, with or without sodium nitrite, in smoked,...

  4. Drought increases forage nitrate and cyanide.

    PubMed

    Pickrell, J A; Oehme, F W; Hickman, S R

    1991-06-01

    To investigate drought-associated increases in concentrations of nitrate and cyanide in animal forage, we compared forage nitrate and cyanide in 1986-87 (annual rainfall 33 in) to nitrate and cyanide in a drought (1988 and 1989; annual rainfall 20 and 27 in, respectively). Fifteen to 20% of the nitrate and cyanide samples from 1986-1987 had sufficiently high concentrations to be of concern (3000 ppm nitrate, 20 ppm cyanide as submitted). Only 4-6% of the 1986-1987 samples had concentrations sufficiently high to produce acute respiratory distress (13,000 ppm nitrate, 50 ppm cyanide as submitted). During 1988 sample numbers had more than doubled, suggesting increased concern for the possibility of nitrate or cyanide intoxication and yielding parallel increases in the number of samples with elevated nitrates or cyanides. By 1989, 25-33% of the samples had concentrations of health concern with respect to either nitrate or cyanide, while 14-19% had concentrations sufficiently high to produce acute respiratory signs. Shortages of forage caused by a 2-y drought were further exacerbated by nitrate and cyanide increases in that feed. Future efforts should concentrate on controlling groundwater nitrate and delivery of nitrate to the plant root-systems. PMID:1858304

  5. Efflux Of Nitrate From Hydroponically Grown Wheat

    NASA Technical Reports Server (NTRS)

    Huffaker, R. C.; Aslam, M.; Ward, M. R.

    1992-01-01

    Report describes experiments to measure influx, and efflux of nitrate from hydroponically grown wheat seedlings. Ratio between efflux and influx greater in darkness than in light; increased with concentration of nitrate in nutrient solution. On basis of experiments, authors suggest nutrient solution optimized at lowest possible concentration of nitrate.

  6. High concentrations of phosphate and nitrate in

    E-print Network

    Langendoen, Koen

    High concentrations of phosphate and nitrate in surface water can lead to an excessive growth phosphate and nitrate from wastewater, resulting in cost savings and more stable process conditions. By purifying phosphate and nitrate from wastewater simultaneously, treatment plants need less filter systems

  7. 21 CFR 172.170 - Sodium nitrate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...3 2013-04-01 2013-04-01 false Sodium nitrate. 172.170 Section 172.170 Food...CONSUMPTION Food Preservatives § 172.170 Sodium nitrate. The food additive sodium nitrate may be safely used in or on...

  8. 21 CFR 172.170 - Sodium nitrate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...3 2014-04-01 2014-04-01 false Sodium nitrate. 172.170 Section 172.170 Food...CONSUMPTION Food Preservatives § 172.170 Sodium nitrate. The food additive sodium nitrate may be safely used in or on...

  9. 21 CFR 172.170 - Sodium nitrate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 3 2010-04-01 2009-04-01 true Sodium nitrate. 172.170 Section 172.170 Food...CONSUMPTION Food Preservatives § 172.170 Sodium nitrate. The food additive sodium nitrate may be safely used in or on...

  10. 21 CFR 172.170 - Sodium nitrate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...3 2011-04-01 2011-04-01 false Sodium nitrate. 172.170 Section 172.170 Food...CONSUMPTION Food Preservatives § 172.170 Sodium nitrate. The food additive sodium nitrate may be safely used in or on...

  11. 21 CFR 172.170 - Sodium nitrate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...3 2012-04-01 2012-04-01 false Sodium nitrate. 172.170 Section 172.170 Food...CONSUMPTION Food Preservatives § 172.170 Sodium nitrate. The food additive sodium nitrate may be safely used in or on...

  12. Modeling nitrate removal in a denitrification bed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Denitrification beds are being promoted to reduce nitrate concentrations in agricultural drainage water to alleviate the adverse environmental effects associated with nitrate pollution in surface water. In this system, water flows through a trench filled with a carbon media where nitrate is transfor...

  13. 76 FR 62311 - Ammonium Nitrate Security Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-07

    ...DHS-2008-0076] RIN 1601-AA52 Ammonium Nitrate Security Program AGENCY: National Protection...rulemaking (NPRM), entitled ``Ammonium Nitrate Security Program,'' which was published...regulate the sale and transfer of ammonium nitrate pursuant to section 563 of the...

  14. Nitration of Naphthol: A Laboratory Experiment.

    ERIC Educational Resources Information Center

    Mowery, Dwight F.

    1982-01-01

    Products of nitrations, upon distillation or steam distillation, may produce dermatitis in some students. A procedure for nitration of beta-naphthol producing a relatively non-volatile product not purified by steam distillation is described. Nitration of alpha-naphthol by the same procedure yields Martius Yellow dye which dyes wool yellow or…

  15. Characterization of uranium and uranium-zirconium deposits produced in electrorefining of spent nuclear fuel

    SciTech Connect

    Totemeier, T.C.

    1997-09-01

    This paper describes the metallurgical characterization of deposits produced in molten salt electrorefining of uranium and uranium - 10.% zirconium alloy. The techniques of characterization are described with emphasis on considerations given to the radioactive and pyrophoric nature of the samples. The morphologies observed and their implications for deposit performance are also presented - samples from pure uranium deposits were comprised of chains of uranium crystals with a characteristic rhomboidal shape, while morphologies of samples from deposits containing zirconium showed more polycrystalline features. Zirconium was found to be present as a second, zirconium metal phase at or very near the uranium-zirconium dendrite surfaces. Higher collection efficiencies and total deposit weights were observed for the uranium-zirconium deposits; this performance increase is likely a result of better mechanical properties exhibited by the uranium-zirconium dendrite morphology. 18 refs., 10 figs., 1 tab.

  16. 49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...nitrate or ammonium nitrate fertilizer not listed in § 176.410... (2) Ammonium nitrate fertilizer, Division 5.1 (oxidizer... (4) Ammonium nitrate fertilizer, Class 9, UN 2071. ...is Explosives, blasting, type E, Division 1.5...

  17. 49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...nitrate or ammonium nitrate fertilizer not listed in § 176.410... (2) Ammonium nitrate fertilizer, Division 5.1 (oxidizer... (4) Ammonium nitrate fertilizer, Class 9, UN 2071. ...is Explosives, blasting, type E, Division 1.5...

  18. 49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...nitrate or ammonium nitrate fertilizer not listed in § 176.410... (2) Ammonium nitrate fertilizer, Division 5.1 (oxidizer... (4) Ammonium nitrate fertilizer, Class 9, UN 2071. ...is Explosives, blasting, type E, Division 1.5...

  19. 49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...nitrate or ammonium nitrate fertilizer not listed in § 176.410... (2) Ammonium nitrate fertilizer, Division 5.1 (oxidizer... (4) Ammonium nitrate fertilizer, Class 9, UN 2071. ...is Explosives, blasting, type E, Division 1.5...

  20. 49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...nitrate or ammonium nitrate fertilizer not listed in § 176.410... (2) Ammonium nitrate fertilizer, Division 5.1 (oxidizer... (4) Ammonium nitrate fertilizer, Class 9, UN 2071. ...is Explosives, blasting, type E, Division 1.5...

  1. Zirconium nanoparticles prepared by the reduction of zirconium oxide using the RAPET method

    PubMed Central

    Eshed, Michal; Pol, Swati; Balasubramanian, Mahalingam

    2011-01-01

    Summary The aim of the current work is the synthesis and characterization of metallic Zr nanoparticles. The preparation is carried out by using the RAPET method (Reaction under Autogenic Pressure at Elevated Temperatures) developed in our lab. The RAPET reaction of commercial ZrO2 with Mg powder was carried out in a closed stainless steel cell, at 750 °C. On completion of the reaction, the additionally formed MgO is removed by treatment with acid. The characterization of the product was performed by XRD, X-ray absorption spectroscopy, SEM, TEM and elemental analysis. The XRD pattern reveals that the product is composed of pure metallic zirconium, without any traces of the MgO by-product. PMID:21977431

  2. Antimicrobial effects of silver zeolite, silver zirconium phosphate silicate and silver zirconium phosphate against oral microorganisms

    PubMed Central

    Saengmee-anupharb, Sirikamon; Srikhirin, Toemsak; Thaweboon, Boonyanit; Thaweboon, Sroisiri; Amornsakchai, Taweechai; Dechkunakorn, Surachai; Suddhasthira, Theeralaksna; Kamaguchi, Arihide

    2013-01-01

    Objective To evaluate the antimicrobial activities of silver inorganic materials, including silver zeolite (AgZ), silver zirconium phosphate silicate (AgZrPSi) and silver zirconium phosphate (AgZrP), against oral microorganisms. In line with this objective, the morphology and structure of each type of silver based powders were also investigated. Methods The antimicrobial activities of AgZ, AgZrPSi and AgZrP were tested against Streptococcus mutans, Lactobacillus casei, Candida albicans and Staphylococcus aureus using disk diffusion assay as a screening test. The minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC) were determined using the modified membrane method. Scanning electron microscope and X-ray diffraction were used to investigate the morphology and structure of these silver materials. Results All forms of silver inorganic materials could inhibit the growth of all test microorganisms. The MIC of AgZ, AgZrPSi and AgZrP was 10.0 g/L whereas MLC ranged between 10.0–60.0 g/L. In terms of morphology and structure, AgZrPSi and AgZrP had smaller sized particles (1.5–3.0 µm) and more uniformly shaped than AgZ. Conclusions Silver inorganic materials in the form of AgZ, AgZrPSi and AgZrP had antimicrobial effects against all test oral microorganisms and those activities may be influenced by the crystal structure of carriers. These results suggest that these silver materials may be useful metals applied to oral hygiene products to provide antimicrobial activity against oral infection. PMID:23570016

  3. Continuous flow nitration in miniaturized devices

    PubMed Central

    2014-01-01

    Summary This review highlights the state of the art in the field of continuous flow nitration with miniaturized devices. Although nitration has been one of the oldest and most important unit reactions, the advent of miniaturized devices has paved the way for new opportunities to reconsider the conventional approach for exothermic and selectivity sensitive nitration reactions. Four different approaches to flow nitration with microreactors are presented herein and discussed in view of their advantages, limitations and applicability of the information towards scale-up. Selected recent patents that disclose scale-up methodologies for continuous flow nitration are also briefly reviewed. PMID:24605161

  4. Surface characterization of anodized zirconium for biomedical applications

    NASA Astrophysics Data System (ADS)

    Sanchez, A. Gomez; Schreiner, W.; Duffó, G.; Ceré, S.

    2011-05-01

    Mechanical properties and corrosion resistance of zirconium make this material suitable for biomedical implants. Its good in vivo performance is mainly due to the presence of a protective oxide layer that minimizes corrosion rate, diminishes the amount of metallic ions released to the biological media and facilitates the osseointegration process. Since the implant surface is the region in contact with living tissues, the characteristics of the surface film are of great interest. Surface modification is a route to enhance both biocompatibility and corrosion resistance of permanent implant materials. Anodizing is presented as an interesting process to modify metal surfaces with good reproducibility and independence of the geometry. In this work the surface of zirconium before and after anodizing in 1 mol/L phosphoric acid solution at a fixed potential between 3 and 30 V, was characterized by means of several surface techniques. It was found that during anodization the surface oxide grows with an inhomogeneous coverage on zirconium surface, modifying the topography. The incorporation of P from the electrolyte to the surface oxide during the anodizing process changes the surface chemistry. After 30 days of immersion in Simulated Body Fluid (SBF) solution, Ca-P rich compounds were present on anodized zirconium.

  5. Solid State Phase Transformations in Uranium-Zirconium Alloys 

    E-print Network

    Irukuvarghula, Sandeep

    2013-08-06

    Uranium-10wt% zirconium (U-10Zr) alloy nuclear fuels have been used for decades and new variations are under consideration ranging from U-5Zr to U-50Zr. As a precursor to understanding the fission gas behavior in U-Zr ...

  6. Hydrogen pickup measurements in zirconium alloys: Relation to oxidation kinetics

    E-print Network

    Motta, Arthur T.

    Hydrogen pickup measurements in zirconium alloys: Relation to oxidation kinetics Adrien Couet a to reduce hydrogen pickup during operation, and the associated cladding degradation. The present study focuses on precisely and accurately measuring hydrogen pickup fraction for a set of alloys to specifically

  7. Discovery of Yttrium, Zirconium, Niobium, Technetium, and Ruthenium Isotopes

    E-print Network

    Nystrom, A

    2011-01-01

    Currently, thirty-four yttrium, thirty-five zirconium, thirty-four niobium, thirty-five technetium, and thirty-eight ruthenium isotopes have been observed and the discovery of these isotopes is discussed here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.

  8. Discovery of Yttrium, Zirconium, Niobium, Technetium, and Ruthenium Isotopes

    E-print Network

    A. Nystrom; M. Thoennessen

    2011-02-11

    Currently, thirty-four yttrium, thirty-five zirconium, thirty-four niobium, thirty-five technetium, and thirty-eight ruthenium isotopes have been observed and the discovery of these isotopes is discussed here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.

  9. Nanophase Nickel-Zirconium Alloys for Fuel Cells

    NASA Technical Reports Server (NTRS)

    Narayanan, Sekharipuram; Whitacre, jay; Valdez, Thomas

    2008-01-01

    Nanophase nickel-zirconium alloys have been investigated for use as electrically conductive coatings and catalyst supports in fuel cells. Heretofore, noble metals have been used because they resist corrosion in the harsh, acidic fuel cell interior environments. However, the high cost of noble metals has prompted a search for less-costly substitutes. Nickel-zirconium alloys belong to a class of base metal alloys formed from transition elements of widely different d-electron configurations. These alloys generally exhibit unique physical, chemical, and metallurgical properties that can include corrosion resistance. Inasmuch as corrosion is accelerated by free-energy differences between bulk material and grain boundaries, it was conjectured that amorphous (glassy) and nanophase forms of these alloys could offer the desired corrosion resistance. For experiments to test the conjecture, thin alloy films containing various proportions of nickel and zirconium were deposited by magnetron and radiofrequency co-sputtering of nickel and zirconium. The results of x-ray diffraction studies of the deposited films suggested that the films had a nanophase and nearly amorphous character.

  10. 40 CFR 721.10601 - Lanthanum lead titanium zirconium oxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...aggregate of releases for the following substances: Lead strontium titanium zirconium oxide (PMN P-11-270; CAS No. 61461-40-3...P-11-271; CAS No. 1262279-31-1); Calcium cobalt lead strontium titanium tungsten oxide (PMN P-11-272; CAS No....

  11. 40 CFR 721.10602 - Lead niobium titanium zirconium oxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...aggregate of releases for the following substances: Lead strontium titanium zirconium oxide (PMN P-11-270; CAS No. 61461-40-3...P-11-271; CAS No. 1262279-31-1); Calcium cobalt lead strontium titanium tungsten oxide (PMN P-11-272; CAS No....

  12. 40 CFR 721.10601 - Lanthanum lead titanium zirconium oxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...aggregate of releases for the following substances: Lead strontium titanium zirconium oxide (PMN P-11-270; CAS No. 61461-40-3...P-11-271; CAS No. 1262279-31-1); Calcium cobalt lead strontium titanium tungsten oxide (PMN P-11-272; CAS No....

  13. 40 CFR 721.10602 - Lead niobium titanium zirconium oxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...aggregate of releases for the following substances: Lead strontium titanium zirconium oxide (PMN P-11-270; CAS No. 61461-40-3...P-11-271; CAS No. 1262279-31-1); Calcium cobalt lead strontium titanium tungsten oxide (PMN P-11-272; CAS No....

  14. The corrosion of zirconium under deep geologic repository conditions

    NASA Astrophysics Data System (ADS)

    Shoesmith, David W.; Zagidulin, Dmitrij

    2011-11-01

    Zirconium alloys are widely used in nuclear reactors as fuel cladding and as reactor structural elements (i.e., CANDU reactor pressure tubes), and are therefore a component of the waste materials that could be emplaced in a deep geologic repository. Therefore, the corrosion mechanisms and rates for relevant zirconium alloys under repository conditions have been reviewed. Since titanium and zirconium alloys have many similarities, and because the data base for the corrosion of titanium alloys under repository conditions is considerably more extensive than that for zirconium alloys, the electrochemical and corrosion behavior of both materials have been compared and evaluated. Although electrochemical studies suggest Zircaloy cladding could be susceptible to pitting, redox conditions within a failed waste container will remain reducing and unable to support pitting. This leaves passive corrosion as the only long-term corrosion mechanism. The available data indicates that the rate of passive corrosion will be very low. A rate of 20 nm/year would be a reasonable upper limit but it is likely the rate will be less than 1 nm/year.

  15. Screw dislocation in zirconium: An ab initio study

    NASA Astrophysics Data System (ADS)

    Clouet, Emmanuel

    2012-10-01

    Plasticity in zirconium is controlled by 1/3<12¯10> screw dislocations gliding in the prism planes of the hexagonal close-packed structure. This prismatic and not basal glide is observed for a given set of transition metals like zirconium and is known to be related to the number of valence electrons in the d band. We use ab initio calculations based on the density functional theory to study the core structure of screw dislocations in zirconium. Dislocations are found to dissociate in the prism plane in two partial dislocations, each with a pure screw character. Ab initio calculations also show that the dissociation in the basal plane is unstable. We calculate then the Peierls barrier for a screw dislocation gliding in the prism plane and obtain a small barrier. The Peierls stress deduced from this barrier is lower than 21 MPa, which is in agreement with experimental data. The ability of an empirical potential relying on the embedded atom method (EAM) to model dislocations in zirconium is also tested against these ab initio calculations.

  16. Synthesis and Liquid Crystal Phase Transitions of Zirconium Phosphate Disks 

    E-print Network

    Shuai, Min

    2013-05-07

    -shaped nanoparticles, and use it for the study of self-assembly and discotic liquid crystal phase transitions of discotic particles. The work was introduced by the control over the size and polydispersity of zirconium phosphate (ZrP) disks through synthesis...

  17. 49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as... Captain of the Port (COTP). (1) Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more...

  18. 49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as... Captain of the Port (COTP). (1) Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more...

  19. 49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as... Captain of the Port (COTP). (1) Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more...

  20. 49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as... Captain of the Port (COTP). (1) Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more...

  1. 49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as... Captain of the Port (COTP). (1) Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more...

  2. High performance ammonium nitrate propellant

    NASA Technical Reports Server (NTRS)

    Anderson, F. A. (inventor)

    1979-01-01

    A high performance propellant having greatly reduced hydrogen chloride emission is presented. It is comprised of: (1) a minor amount of hydrocarbon binder (10-15%), (2) at least 85% solids including ammonium nitrate as the primary oxidizer (about 40% to 70%), (3) a significant amount (5-25%) powdered metal fuel, such as aluminum, (4) a small amount (5-25%) of ammonium perchlorate as a supplementary oxidizer, and (5) optionally a small amount (0-20%) of a nitramine.

  3. Layered zirconium phosphonate with inorganic–organic hybrid structure: Preparation and its assembly with DNA

    SciTech Connect

    Liu, Li-Min; Lu, Guo-Yuan; Jiang, Li-Ping; Zhu, Jun-Jie

    2014-07-01

    An aminoethoxy-functionalized zirconium phosphonate (Zr(O{sub 3}POCH{sub 2}CH{sub 2}NH{sub 2}){sub 2}·3H{sub 2}O), abbreviated as ZrRP (R=OCH{sub 2}CH{sub 2}NH{sub 2}), with layered structure has been synthesized. This layered compound possesses the characteristic of inorganic–organic hybrid, due to the covalently linked aminoethoxy in the host layer. The anion exchanged property of this zirconium phosphonate is suitable for the direct intercalation of negatively charged DNA, which is different from these reported zirconium phosphates or zirconium phosphonates. As a precursor, this prepared zirconium phosphonate was utilized to fabricate a novel DNA/ZrRP binary hybrid via a delamination-reassembly procedure. The release behavior of DNA from the DNA/ZrRP composite was investigated at different medium pH, because the combination between zirconium phosphonate sheets and DNA was pH-dependent sensitively. Moreover, the helical conformation of DNA was almost retained after the intercalation and release process. These properties of the DNA/ZrRP composite suggested the potential application of layered zirconium phosphonate as a non-viral vector in gene delivery. - Graphical abstract: The intercalation of DNA into zirconium phosphonate and the release of DNA from the interlayer of zirconium phosphonate. - Highlights: ?A layered aminoethoxy-functionalized zirconium phosphonate has been synthesized. ?DNA was intercalated directly into the prepared zirconium phosphonate. ?A novel zirconium phosphonate/DNA binary hybrid was fabricated. ?DNA can be reversibly released from the interlayer of zirconium phosphonate. ?The intercalation/release processes do not induce the denaturalization of DNA.

  4. Photochemical reduction of uranyl nitrate

    SciTech Connect

    Duerksen, W.K.

    1993-10-20

    The photochemical reduction of uranyl nitrate solutions to tetravalent uranium was investigated as a means of producing uranium dioxide feed for the saltless direct oxide reduction (SDOR) process. At high uranium concentrations, reoxidation of U{sup +4} occurs rapidly. The kinetics of the nitric oxidation of tetravalent uranium depend on the concentrations of hydrogen ion, nitrate ion, nitrous acid, and tetravalent uranium in the same manner as was reported elsewhere for the nitrate oxidation of PU{sup +3}. Reaction rate data were successfully correlated with a mechanism in which nitrogen dioxide is the reactive intermediate. Addition of a nitrous acid scavenger suppresses the reoxidation reaction. An immersion reactor employing a mercury vapor lamp gave reduction times fast enough for routine production usage. Precipitation techniques for conversion of aqueous U(NO{sub 3}){sub 4} to hydrous UO{sub 2} were evaluated. Prolonged dewatering times tended to make the process time consuming. Use of 3- to 4-M aqueous NaOH gave the best dewatering times observed. Reoxidation of the UO{sub 2} by water of hydration was encountered, which required the drying process to be carried out under a reducing atmosphere.

  5. Aripiprazole salts. I. Aripiprazole nitrate.

    PubMed

    Freire, Eleonora; Polla, Griselda; Baggio, Ricardo

    2012-04-01

    The crystal structure of aripiprazole nitrate (systematic name: 4-(2,3-dichlorophenyl)-1-{4-[(2-oxo-1,2,3,4-tetrahydroquinolin-7-yl)oxy]butyl}piperazin-1-ium nitrate), C(23)H(28)Cl(2)N(3)O(2)(+)·NO(3)(-) or AripH(+)·NO(3)(-), is presented and the molecule compared with the aripiprazole molecules reported so far in the literature. Bond distances and angles appear very similar, except for a slight lengthening of the C-NH distances involving the protonated N atom, and the main differences are to be found in the molecular spatial arrangement (revealed by the sequence of torsion angles) and the intermolecular interactions (resulting from structural elements specific to this structure, viz. the nitrate counter-ions on one hand and the extra protons on the other hand as hydrogen-bond acceptors and donors, respectively). The result is the formation of [100] strips, laterally linked by weak ?-? and C-Cl...? interactions, leading to a family of undulating sheets parallel to (010). PMID:22476150

  6. Experiments on interactions between zirconium-containing melt and water (ZREX): Hydrogen generation and chemical augmentation of energetics

    SciTech Connect

    Cho, D.H.; Armstrong, D.R.; Gunther, W.H.; Basu, S.

    1997-08-01

    The results of the first data series of experiments on interactions between zirconium-containing melt and water are described. These experiments involved dropping 1-kg batches of pure zirconium or zirconium-zirconium dioxide mixture melt into a column of water. A total of nine tests were conducted, including four with pure zirconium melt and five with Zr-ZrO{sub 2} mixture melt. Explosions took place only in those tests which were externally triggered. While the extent of zirconium oxidation in the triggered experiments was quite extensive, the estimated explosion energetics were found to be very small compared to the combined thermal and chemical energy available.

  7. Phylogenomics of Mycobacterium Nitrate Reductase Operon.

    PubMed

    Huang, Qinqin; Abdalla, Abualgasim Elgaili; Xie, Jianping

    2015-07-01

    NarGHJI operon encodes a nitrate reductase that can reduce nitrate to nitrite. This process enhances bacterial survival by nitrate respiration under anaerobic conditions. NarGHJI operon exists in many bacteria, especially saprophytic bacteria living in soil which play a key role in the nitrogen cycle. Most actinomycetes, including Mycobacterium tuberculosis, possess NarGHJI operons. M. tuberculosis is a facultative intracellular pathogen that expands in macrophages and has the ability to persist in a non-replicative form in granuloma lifelong. Nitrogen and nitrogen compounds play crucial roles in the struggle between M. tuberculosis and host. M. tuberculosis can use nitrate as a final electron acceptor under anaerobic conditions to enhance its survival. In this article, we reviewed the mechanisms regulating nitrate reductase expression and affecting its activity. Potential genes involved in regulating the nitrate reductase expression in M. tuberculosis were identified. The conserved NarG might be an alternative mycobacterium taxonomic marker. PMID:25980349

  8. Safety in the Chemical Laboratory: Nitric Acid, Nitrates, and Nitro Compounds.

    ERIC Educational Resources Information Center

    Bretherick, Leslie

    1989-01-01

    Discussed are the potential hazards associated with nitric acid, inorganic and organic nitrate salts, alkyl nitrates, acyl nitrates, aliphatic nitro compounds, aromatic nitro compounds, and nitration reactions. (CW)

  9. 49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Explosives, blasting, type E, and Explosives, blasting, type B, Division 1.5...Ammonium nitrate fertilizer, Division 5.1...and ammonium nitrate fertilizers classed as Division...Explosives, blasting, type B, and...

  10. 49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Explosives, blasting, type E, and Explosives, blasting, type B, Division 1.5...Ammonium nitrate fertilizer, Division 5.1...and ammonium nitrate fertilizers classed as Division...Explosives, blasting, type B, and...

  11. 49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Explosives, blasting, type E, and Explosives, blasting, type B, Division 1.5...Ammonium nitrate fertilizer, Division 5.1...and ammonium nitrate fertilizers classed as Division...Explosives, blasting, type B, and...

  12. 49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Explosives, blasting, type E, and Explosives, blasting, type B, Division 1.5...Ammonium nitrate fertilizer, Division 5.1...and ammonium nitrate fertilizers classed as Division...Explosives, blasting, type B, and...

  13. 49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Explosives, blasting, type E, and Explosives, blasting, type B, Division 1.5...Ammonium nitrate fertilizer, Division 5.1...and ammonium nitrate fertilizers classed as Division...Explosives, blasting, type B, and...

  14. Trend Analyses of Nitrate in Danish Groundwater

    NASA Astrophysics Data System (ADS)

    Hansen, B.; Thorling, L.; Dalgaard, T.; Erlandsen, M.

    2012-04-01

    This presentation assesses the long-term development in the oxic groundwater nitrate concentration and nitrogen (N) loss due to intensive farming in Denmark. Firstly, up to 20-year time-series from the national groundwater monitoring network enable a statistically systematic analysis of distribution, trends and trend reversals in the groundwater nitrate concentration. Secondly, knowledge about the N surplus in Danish agriculture since 1950 is used as an indicator of the potential loss of N. Thirdly, groundwater recharge CFC (Chlorofluorocarbon) age determination allows linking of the first two dataset. The development in the nitrate concentration of oxic groundwater clearly mirrors the development in the national agricultural N surplus, and a corresponding trend reversal is found in groundwater. Regulation and technical improvements in the intensive farming in Denmark have succeeded in decreasing the N surplus by 40% since the mid 1980s while at the same time maintaining crop yields and increasing the animal production of especially pigs. Trend analyses prove that the youngest (0-15 years old) oxic groundwater shows more pronounced significant downward nitrate trends (44%) than the oldest (25-50 years old) oxic groundwater (9%). This amounts to clear evidence of the effect of reduced nitrate leaching on groundwater nitrate concentrations in Denmark. Are the Danish groundwater monitoring strategy obtimal for detection of nitrate trends? Will the nitrate concentrations in Danish groundwater continue to decrease or are the Danish nitrate concentration levels now appropriate according to the Water Framework Directive?

  15. Photochemistry of Nitrate Adsorbed on Mineral Dust

    NASA Astrophysics Data System (ADS)

    Gankanda, A.; Grassian, V. H.

    2013-12-01

    Mineral dust particles in the atmosphere are often associated with adsorbed nitrate from heterogeneous reactions with nitrogen oxides including HNO3 and NO2. Although nitrate ion is a well-studied chromophore in natural waters, the photochemistry of adsorbed nitrate on mineral dust particles is yet to be fully explored. In this study, wavelength dependence of the photochemistry of adsorbed nitrate on different model components of mineral dust aerosol has been investigated using transmission FTIR spectroscopy. Al2O3, TiO2 and NaY zeolite were used as model systems to represent non-photoactive oxides, photoactive semiconductor oxides and porous materials respectively, present in mineral dust aerosol. In this study, adsorbed nitrate is irradiated with 254 nm, 310 nm and 350 nm narrow band light. In the irradiation with narrow band light, NO2 is the only detectable gas-phase product formed from nitrate adsorbed on Al2O3 and TiO2. The NO2 yield is highest at 310 nm for both Al2O3 and TiO2. Unlike Al2O3 and TiO2, in zeolite, adsorbed nitrate photolysis to nitrite is observed only at 310 nm during narrow band irradiation. Moreover gas phase products were not detected during nitrate photolysis in zeolite at all three wavelengths. The significance of these differences as related to nitrate photochemistry on different mineral dust components will be highlighted.

  16. A review on hydride precipitation in zirconium alloys

    NASA Astrophysics Data System (ADS)

    Bair, Jacob; Asle Zaeem, Mohsen; Tonks, Michael

    2015-11-01

    Nucleation and formation of hydride precipitates in zirconium alloys have been an important factor in limiting the lifetime of nuclear fuel cladding for over 50 years. This review provides a concise summary of experimental and computational studies performed on hydride precipitation in zirconium alloys since the 1960's. Different computational models, including density functional theory, molecular dynamics, phase field, and finite element models applied to study hydride precipitation are reviewed, with specific consideration given to the phase field model, which has become a popular and powerful computational tool for modeling microstructure evolution. The strengths and weaknesses of these models are discussed in detail. An outline of potential future work in this area is discussed as well.

  17. Corrosion behavior of stainless steel-zirconium alloy waste forms.

    SciTech Connect

    Abraham, D. P.

    1999-01-13

    Stainless steel-zirconium (SS-Zr) alloys are being considered as waste forms for the disposal of metallic waste generated during the electrometallurgical treatment of spent nuclear fuel. The baseline waste form for spent fuels from the EBR-II reactor is a stainless steel-15 wt.% zirconium (SS-15Zr) alloy. This article briefly reviews the microstructure of various SS-Zr waste form alloys and presents results of immersion corrosion and electrochemical corrosion tests performed on these alloys. The electrochemical tests show that the corrosion behavior of SS-Zr alloys is comparable to those of other alloys being considered for the Yucca Mountain geologic repository. The immersion tests demonstrate that the SS-Zr alloys are resistant to selective leaching of fission product elements and, hence, suitable as candidates for high-level nuclear waste forms.

  18. Effects of solutes on damage production and recovery in zirconium

    SciTech Connect

    Zee, R.H.; Birtcher, R.C.; MacEwen, S.R.; Abromeit, C.

    1986-04-01

    Dilute zirconium-based alloys and pure zirconium were irradiated at 10 K with spallation neutrons at IPNS. Four types of alloys - Zr-Ti, Zr-Sn, Zr-Dy and Zr-Au - each with three concentration levels, were used. Low-temperature resistivity damage rates are enhanced by the presence of any of the four solutes. The greatest enhancement was produced by Au while the least by Dy. Within each alloy group, damage production also increased but at a decreasing rate, with increasing concentration. Post-irradiation annealing experiments, up to 400 K, showed that all four solutes suppress recovery due to interstitial migration, indicative of interstitial trapping by the solutes. Vacancy recovery is also suppressed by the presence of Sn, Dy or Au. The effect of Ti is to shift this stage to lower temperature. No clear correlation between the results with solute size was detected.

  19. Alternative Processing of High Temperature Hafnium and Zirconium Based Materials

    NASA Technical Reports Server (NTRS)

    Gasch, Matthew; Gusman, Michael; Ellerby, Don; Irby, Edward; Johnson, Sylvia M.

    2003-01-01

    The behavior of refractory hafnium and zirconium based materials are being investigated at NASA Ames as part of ongoing research aimed at developing superior heat resistant materials for aerospace applications. Hafnium and zirconium diboride based materials have shown high temperature capabilities in simulated reentry environments indicating that these materials may successfully operate as reusable oxidation resistant components for leading edge applications. Due to the refractory nature of these materials, processing of fine-grained uniform microstructures poses a number of challenges. To better understand the process-property-microstructure relationship, processing of these materials has been carried out with conventional hot pressing in addition to the novel approach of Spark Plasma Sintering (SPS). The two processing methods are compared and contrasted in an evaluation of the sintering behavior of high temperature diboride based materials and preliminary physical and mechanical properties are presented.

  20. Modelling zirconium hydrides using the special quasirandom structure approach.

    PubMed

    Wang, H; Chroneos, A; Jiang, C; Schwingenschlögl, U

    2013-05-28

    The study of the structure and properties of zirconium hydrides is important for understanding the embrittlement of zirconium alloys used as cladding in light water nuclear reactors. Simulation of the defect processes is complicated due to the random distribution of the hydrogen atoms. We propose the use of the special quasirandom structure approach as a computationally efficient way to describe this random distribution. We have generated six special quasirandom structure cells based on face centered cubic and face centered tetragonal unit cells to describe ZrH(2-x) (x = 0.25-0.5). Using density functional theory calculations we investigate the mechanical properties, stability, and electronic structure of the alloys. PMID:23588997

  1. Effect of Carbon Dioxide on Nitrate Accumulation and Nitrate Reductase Induction in Corn Seedlings 1

    PubMed Central

    Purvis, A. C.; Peters, D. B.; Hageman, R. H.

    1974-01-01

    Exposure of the leaf canopy of corn seedlings (Zea mays L.) to atmospheric CO2 levels ranging from 100 to 800 ?l/l decreased nitrate accumulation and nitrate reductase activity. Plants pretreated with CO2 in the dark and maintained in an atmosphere containing 100 ?l/l CO2 accumulated 7-fold more nitrate and had 2-fold more nitrate reductase activity than plants exposed to 600 ?l/l CO2, after 5 hours of illumination. Induction of nitrate reductase activity in leaves of intact corn seedlings was related to nitrate content. Changes in soluble protein were related to in vitro nitrate reductase activity suggesting that in vitro nitrate reductase activity was a measure of in situ nitrate reduction. In longer experiments, levels of nitrate reductase and accumulation of reduced N supported the concept that less nitrate was being absorbed, translocated, and assimilated when CO2 was high. Plants exposed to increasing CO2 levels for 3 to 4 hours in the light had increased concentrations of malate and decreased concentrations of nitrate in the leaf tissue. Malate and nitrate concentrations in the leaf tissue of seven of eight corn genotypes grown under comparable and normal (300 ?l/l CO2) environments, were negatively correlated. Exposure of roots to increasing concentrations of potassium carbonate with or without potassium sulfate caused a progressive increase in malate concentrations in the roots. When these roots were subsequently transferred to a nitrate medium, the accumulation of nitrate was inversely related to the initial malate concentrations. These data suggest that the concentration of malate in the tissue seem to be related to the accumulation of nitrate. PMID:16658819

  2. Dissolution-passivation model for zirconium alloys in fluorinated media

    SciTech Connect

    Prono, J.; Caprani, A.; Jaszay, T.; Frayret, J.P.

    1992-12-31

    Considering the shape of the steady state current-potential curve, we proposed a dissolution-passivation model composed of five determining steps and we calculated the associated elementary rates. Two different compounds of tetravalent zirconium are involved in the formation of the surface film. The influence of temperature on the elementary rates allows us to consider the chemical dissolution as the slowest steps and to involve fluoride in the formation of the film in the vicinity of the corrosion potential.

  3. Distribution coefficients of rare earth ions in cubic zirconium dioxide

    NASA Astrophysics Data System (ADS)

    Romer, H.; Luther, K.-D.; Assmus, W.

    1994-08-01

    Cubic zirconium dioxide crystals are grown with the skull melting technique. The effective distribution coefficients for Nd(exp 3+), Sm(exp 3+) and Er(sup 3+) as dopants are determined experimentally as a function of the crystal growth velocity. With the Burton-Prim-Slichter theory, the equilibrium distribution coefficients can be calculated. The distribution coefficients of all other trivalent rare earth ions can be estimated by applying the correlation towards the ionic radii.

  4. Studies of microstructural imperfections of powdered Zirconium-based alloys

    SciTech Connect

    Chowdhury, P.S.; Mukherjee, P.

    2010-11-15

    Different model based approaches of X-ray diffraction line profile analysis have been applied on the heavily deformed zirconium-based alloys in the powdered form to characterize the microstructural parameters like domain size, microstrain and dislocation density. In characterizing the microstructure of the material, these methods are complimentary to each other. Though the parameters obtained by different techniques are differently defined and thus not necessarily comparable, the values of domain size and microstrain obtained from the different techniques show similar trends.

  5. Oxidation characteristics of molybdenum-zirconium oxide cermets

    NASA Technical Reports Server (NTRS)

    Heitzinger, B.

    1984-01-01

    The oxidation of molybdenum is affected by the factors of temperature, the oxygen pressure in the oxidizing atmosphere, and the time of exposure. Studies of the oxidation characteristics of Mo show that the oxidation rate increases strongly when the temperature exceeds 600 C. Investigations of the behavior of cermets with various percentages of zirconium oxide are discussed, taking into account oxidation conditions at temperatures under and above the melting point of molybdenum trioxide.

  6. Nitrates

    MedlinePLUS

    ... or interactions with other medicines and vitamin or herbal supplements. This information should not be used as medical ... your doctor about every medicine and vitamin or herbal supplement that you are taking, so he or she ...

  7. Polyimide nanocomposites based on cubic zirconium tungstate

    NASA Astrophysics Data System (ADS)

    Ramasubramanian Sharma, Gayathri

    2009-12-01

    In this research, cubic zirconium tungstate (ZrW2O8) was used as a filler to reduce the CTE of polyimides (PI), and the effect of ZrW2O8 nanoparticles on the bulk polymer properties was studied. Polyimides are high performance polymers with exceptional thermal stability, and there is a need for PIs with low CTEs for high temperature applications. The nanofiller, cubic ZrW2O8, is well known for its isotropic negative thermal expansion (NTE) over a wide temperature range from -272.7 to 777°C. The preparation of nanocomposites involved the synthesis of ZrW 2O8 nanofiller, engineering the polymer-filler interface using linker groups and optimization of processing strategies to prepare free-standing PI nanocomposite films. A hydrothermal method was used to synthesize ZrW 2O8 nanoparticles. Polyimide-ZrW2O8 interface interaction was enhanced by covalently bonding linker moieties to the surface of ZrW2O8 nanoparticles. Specifically, ZrW 2O8 nanoparticles were functionalized with two different linker groups: (1) a short aliphatic silane, and (2) low molecular weight PI. The surface functionalization was confirmed using X-ray photoelectron spectroscopy and thermal gravimetric analysis (TGA). Reprecipitation blending was used to prepare the freestanding PI-ZrW2O8 nanocomposite films with up to 15 volume% filler loading. SEM images showed the improvements in polymer-filler wetting behavior achieved using interface engineering. SEM images indicated that there was better filler dispersion in the PI matrix using reprecipitation blending, compared to the filler dispersion achieved in the nanocomposites prepared using conventional blending technique. The structure-property relationships in PI-ZrW2O8 nanocomposites were investigated by studying the thermal degradation, glass transition, tensile and thermal expansion properties of the nanocomposites. The properties were studied as a function of filler loading and interface linker groups. Addition of ZrW2O8 nanoparticles did not alter the thermal degradation and glass transition temperatures of the base PI. The addition of ZrW2O8 nanoparticles increased the Young's modulus of the polymer, indicating the stiffening of polyimide matrix. The modulus showed a steady increase with increase in filler loading. The increase was higher for nanocomposites with engineered interface due to the efficient load transfer achieved through the presence of linker groups. The strain at yield and the tensile strength decreased with the addition of ZrW2O8. The experimental results for the moduli of nanocomposites were compared with moduli predicted using theoretical models. The results for the nanocomposites with unmodified ZrW2O8 followed Hashin-Shtrikman (H-S) lower bound, which showed the presence of mechanical interactions between the polymer and filler. The moduli for nanocomposites with engineered interface fell between the H-S bounds, demonstrating the stiffening of PI matrix through efficient load transfer. The addition of ZrW2O8 reduced the in-plane CTE of the base PI at all loadings. The CTE of the nanocomposites decreased steadily with an increase in the filler loading. With the addition of 15 volume% APT-ZrW 2O8, the CTE of the base PI reduced from 64.3 +/- 1.3 ppm/°C to 51.9 +/- 0.9 ppm/°C. In other words, the CTE of the base PI was reduced by around 22% with the addition of ZrW2O 8 at 15 volume% loading. The CTE values were comparable for all samples at similar loadings irrespective of the interface groups. The experimental results for the CTEs of nanocomposites were compared with CTEs predicted using theoretical models. The data followed the Schapery upper bound, which was consistent with the results observed for the moduli data. The effect of ZrW2O8 particle size on the bulk properties of the polyimide was also investigated. The CTE of composites with micron particles at 5 volume% was comparable to that obtained for nanocomposites at the same filler loading. But, there were significant differences in the mechanical strength of composites. PI composites with ZrW2O 8 micron particles were extre

  8. Removal of nitrate from groundwater by cyanobacteria: Quantitative assessment of factors influencing nitrate uptake

    SciTech Connect

    Hu, Q.; Westerhoff, P.; Vermaas, W.

    2000-01-01

    The feasibility of biologically removing nitrate from groundwater was tested by using cyanobacterial cultures in batch mode under laboratory conditions. Results demonstrated that nitrate-contaminated groundwater, when supplemented with phosphate and some trace elements, can be used as growth medium supporting vigorous growth of several strains of cyanobacteria. As cyanobacteria grew, nitrate was removed from the water. Of three species tested, Synechococcus sp. strain PCC 7942 displayed the highest nitrate uptake rate, but all species showed rapid removal of nitrate from groundwater. The nitrate uptake rate increased proportionally with increasing light intensity up to 100 {micro}mol of photons m{sup {minus}2} s{sup {minus}1}, which parallels photosynthetic activity. The nitrate uptake rate was affected by inoculum size (i.e., cell density), fixed-nitrogen level in the cells in the inoculum, and aeration rate, with vigorously aerated, nitrate-sufficient cells in mid-logarithmic phase having the highest long-term nitrate uptake rate. Average nitrate uptake rates up to 0.05 mM NO{sub 3}{sup {minus}} h{sup {minus}1} could be achieved at a culture optical density at 730 nm of 0.5 to 1.0 over a 2-day culture period. This result compares favorably with those reported for nitrate removal by other cyanobacteria and algae, and therefore effective nitrate removal from groundwater using this organism could be anticipated on large-scale operations.

  9. 49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ammonium nitrate mixtures. 176.410 Section 176.410 Transportation Other Regulations Relating to... nitrate and ammonium nitrate mixtures. (a) This section prescribes requirements to be observed with..., blasting, type B, and Explosives, blasting, type E, Division 1.5 compatibility group D. (f) No...

  10. 49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... ammonium nitrate mixtures. 176.410 Section 176.410 Transportation Other Regulations Relating to... nitrate and ammonium nitrate mixtures. (a) This section prescribes requirements to be observed with..., blasting, type B, and Explosives, blasting, type E, Division 1.5 compatibility group D. (f) No...

  11. 49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... ammonium nitrate mixtures. 176.410 Section 176.410 Transportation Other Regulations Relating to... nitrate and ammonium nitrate mixtures. (a) This section prescribes requirements to be observed with..., blasting, type B, and Explosives, blasting, type E, Division 1.5 compatibility group D. (f) No...

  12. 49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... ammonium nitrate mixtures. 176.410 Section 176.410 Transportation Other Regulations Relating to... nitrate and ammonium nitrate mixtures. (a) This section prescribes requirements to be observed with..., blasting, type B, and Explosives, blasting, type E, Division 1.5 compatibility group D. (f) No...

  13. 49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... ammonium nitrate mixtures. 176.410 Section 176.410 Transportation Other Regulations Relating to... nitrate and ammonium nitrate mixtures. (a) This section prescribes requirements to be observed with..., blasting, type B, and Explosives, blasting, type E, Division 1.5 compatibility group D. (f) No...

  14. Challenges with nitrate therapy and nitrate tolerance: prevalence, prevention, and clinical relevance.

    PubMed

    Thadani, Udho

    2014-08-01

    Nitrate therapy has been an effective treatment for ischemic heart disease for over 100 years. The anti-ischemic and exercise-promoting benefits of sublingually administered nitrates are well established. Nitroglycerin is indicated for the relief of an established attack of angina and for prophylactic use, but its effects are short lived. In an effort to increase the duration of beneficial effects, long-acting orally administered and topical applications of nitrates have been developed; however, following their continued or frequent daily use, patients soon develop tolerance to these long-acting nitrate preparations. Once tolerance develops, patients begin losing the protective effects of the long-acting nitrate therapy. By providing a nitrate-free interval, or declining nitrate levels at night, one can overcome or reduce the development of tolerance, but cannot provide 24-h anti-anginal and anti-ischemic protection. In addition, patients may be vulnerable to occurrence of rebound angina and myocardial ischemia during periods of absent nitrate levels at night and early hours of the morning, and worsening of exercise capacity prior to the morning dose of the medication. This has been a concern with nitroglycerin patches but not with oral formulations of isosorbide-5 mononitrates, and has not been adequately studied with isosorbide dinitrate. This paper describes problems associated with nitrate tolerance, reviews mechanisms by which nitrate tolerance and loss of efficacy develop, and presents strategies to avoid nitrate tolerance and maintain efficacy when using long-acting nitrate formulations. PMID:24664980

  15. REDUCTION OF NITRATE THROUGH THE USE OF NITRATE REDUCTASE FOR THE SMARTCHEM AUTOANALYZER

    EPA Science Inventory

    The standard method for the determination of nitrate in drinking water, USEPA Method 353.2 ?Determination of Nitrate-Nitrite by Automated Colorimetry,? employs cadmium as the reductant for the conversion of nitrate to nitrite. The nitrite is then analyzed colorimetrically by way ...

  16. Ferrier rearrangement promoted by an electrochemically generated zirconium catalyst.

    PubMed

    Stevanovi?, Dragana; Pejovi?, Anka; Damljanovi?, Ivan; Mini?, Aleksandra; Bogdanovi?, Goran A; Vuki?evi?, Mirjana; Radulovi?, Niko S; Vuki?evi?, Rastko D

    2015-04-30

    In situ generated zirconium catalyst from a sacrificial zirconium anode was successfully applied to promote Ferrier rearrangement of 3,4,5-tri-O-acetyl-D-glucal and 6-deoxy-3,4-di-O-acetyl-L-glucal (3,4-di-O-acetyl-L-rhamnal) in the presence of three thiols and eleven thiophenols as nucleophiles. A simple constant current electrolysis (20 mA, 0.4 F mol(-1)) of an acetonitrile solution of lithium perchlorate (0.1 M) containing the corresponding glycal and S-nucleophiles, using a zirconium anode and a platinum cathode resulted in the successful synthesis of the corresponding 2,3-unsaturated peracetylated thioglycosides (with an average anomer ratio ?/?=4.129 in the case of peracetylated D-glucal and 8.740 in the case of L-rhamnal). The same procedure proved to be appropriate in synthesizing dihydropyran derivatives ('C-glycosides') using allyltrimethylsilane as the nucleophile (only '?-anomers' were obtained). All new compounds were fully characterized by spectral data, whereas single-crystal X-ray analysis was performed for two thioglycosides. PMID:25746956

  17. Continuous ion exchange separation of zirconium and hafnium

    SciTech Connect

    Begovich, J.M.; Sisson, W.G.

    1981-01-01

    A pressurized continuous annular chromatograph (CAC) has been developed for truly continuous ion exchange preparative separations. This device utilizes a slowly rotating annular bed of sorbent material, fixed multiple feed points, and fixed withdrawal locations. Most of our investigations have been performed with a 28-cm-diam by 60-cm-long CAC, but a larger model has recently been designed and constructed. A detailed study has been made of the separation of copper, nickel, and cobalt components from a simulated carbonate leach liquor of the Caron process for recovering nickel and cobalt from laterite ores. Recent studies have investigated the ion exchange separation of zirconium and hafnium from a sulfate feed solution. Nuclear reactor-grade zirconium, containing < 0.01 wt % hafnium, and hafnium, containing < 1% zirconium, have been continuously prepared using cation exchange resin in the pressurized CAC. This device, because of its continuous feed and product withdrawal, its adaptability to largescale operations, and its ability to separate many components, is expected to make chromatography a more competitive process in the industrial sector.

  18. Laves intermetallics in stainless steel-zirconium alloys

    SciTech Connect

    Abraham, D.P.; McDeavitt, S.M.; Richardson, J.W. Jr.

    1997-05-01

    Laves intermetallics have a significant effect on properties of metal waste forms being developed at Argonne National Laboratory. These waste forms are stainless steel-zirconium alloys that will contain radioactive metal isotopes isolated from spent nuclear fuel by electrometallurgical treatment. The baseline waste form composition for stainless steel-clad fuels is stainless steel-15 wt.% zirconium (SS-15Zr). This article presents results of neutron diffraction measurements, heat-treatment studies and mechanical testing on SS-15Zr alloys. The Laves intermetallics in these alloys, labeled Zr(Fe,Cr,Ni){sub 2+x}, have both C36 and C15 crystal structures. A fraction of these intermetallics transform into (Fe,Cr,Ni){sub 23}Zr{sub 6} during high-temperature annealing; the authors have proposed a mechanism for this transformation. The SS-15Zr alloys show virtually no elongation in uniaxial tension, but exhibit good strength and ductility in compression tests. This article also presents neutron diffraction and microstructural data for a stainless steel-42 wt.% zirconium (SS-42Zr) alloy.

  19. Nitrate Reduction Functional Genes and Nitrate Reduction Potentials Persist in Deeper Estuarine Sediments. Why?

    PubMed Central

    Papaspyrou, Sokratis; Smith, Cindy J.; Dong, Liang F.; Whitby, Corinne; Dumbrell, Alex J.; Nedwell, David B.

    2014-01-01

    Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are processes occurring simultaneously under oxygen-limited or anaerobic conditions, where both compete for nitrate and organic carbon. Despite their ecological importance, there has been little investigation of how denitrification and DNRA potentials and related functional genes vary vertically with sediment depth. Nitrate reduction potentials measured in sediment depth profiles along the Colne estuary were in the upper range of nitrate reduction rates reported from other sediments and showed the existence of strong decreasing trends both with increasing depth and along the estuary. Denitrification potential decreased along the estuary, decreasing more rapidly with depth towards the estuary mouth. In contrast, DNRA potential increased along the estuary. Significant decreases in copy numbers of 16S rRNA and nitrate reducing genes were observed along the estuary and from surface to deeper sediments. Both metabolic potentials and functional genes persisted at sediment depths where porewater nitrate was absent. Transport of nitrate by bioturbation, based on macrofauna distributions, could only account for the upper 10 cm depth of sediment. A several fold higher combined freeze-lysable KCl-extractable nitrate pool compared to porewater nitrate was detected. We hypothesised that his could be attributed to intracellular nitrate pools from nitrate accumulating microorganisms like Thioploca or Beggiatoa. However, pyrosequencing analysis did not detect any such organisms, leaving other bacteria, microbenthic algae, or foraminiferans which have also been shown to accumulate nitrate, as possible candidates. The importance and bioavailability of a KCl-extractable nitrate sediment pool remains to be tested. The significant variation in the vertical pattern and abundance of the various nitrate reducing genes phylotypes reasonably suggests differences in their activity throughout the sediment column. This raises interesting questions as to what the alternative metabolic roles for the various nitrate reductases could be, analogous to the alternative metabolic roles found for nitrite reductases. PMID:24728381

  20. 40 CFR 721.10152 - Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-, hydrolysis products with alkanol zirconium(4+) salt and silica, acetates (generic). 721.10152 Section 721... Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica... substance identified generically as oxirane, substituted silylmethyl-, hydrolysis products with...

  1. 40 CFR 721.10152 - Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-, hydrolysis products with alkanol zirconium(4+) salt and silica, acetates (generic). 721.10152 Section 721... Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica... substance identified generically as oxirane, substituted silylmethyl-, hydrolysis products with...

  2. 40 CFR 721.10152 - Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-, hydrolysis products with alkanol zirconium(4+) salt and silica, acetates (generic). 721.10152 Section 721... Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica... substance identified generically as oxirane, substituted silylmethyl-, hydrolysis products with...

  3. 40 CFR 721.10152 - Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-, hydrolysis products with alkanol zirconium(4+) salt and silica, acetates (generic). 721.10152 Section 721... Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica... substance identified generically as oxirane, substituted silylmethyl-, hydrolysis products with...

  4. 40 CFR 721.10152 - Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-, hydrolysis products with alkanol zirconium(4+) salt and silica, acetates (generic). 721.10152 Section 721... Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica... substance identified generically as oxirane, substituted silylmethyl-, hydrolysis products with...

  5. 46 CFR 148.227 - Calcium nitrate fertilizers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 false Calcium nitrate fertilizers. 148.227 Section 148.227... § 148.227 Calcium nitrate fertilizers. This part does not apply to commercial grades of calcium nitrate fertilizers consisting mainly of a double...

  6. 46 CFR 148.227 - Calcium nitrate fertilizers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Calcium nitrate fertilizers. 148.227 Section 148.227... § 148.227 Calcium nitrate fertilizers. This part does not apply to commercial grades of calcium nitrate fertilizers consisting mainly of a double...

  7. 46 CFR 148.227 - Calcium nitrate fertilizers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Calcium nitrate fertilizers. 148.227 Section 148.227... § 148.227 Calcium nitrate fertilizers. This part does not apply to commercial grades of calcium nitrate fertilizers consisting mainly of a double...

  8. 46 CFR 148.227 - Calcium nitrate fertilizers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 false Calcium nitrate fertilizers. 148.227 Section 148.227... § 148.227 Calcium nitrate fertilizers. This part does not apply to commercial grades of calcium nitrate fertilizers consisting mainly of a double...

  9. 78 FR 32690 - Certain Ammonium Nitrate From Ukraine

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-31

    ...731-TA-894 (Review)] Certain Ammonium Nitrate From Ukraine Determination On the basis...antidumping duty order on certain ammonium nitrate from Ukraine would be likely to lead to...May 2013), entitled Certain Ammonium Nitrate from Ukraine: Investigation No....

  10. 40 CFR 721.7500 - Nitrate polyether polyol (generic name).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Nitrate polyether polyol (generic name). ...Specific Chemical Substances § 721.7500 Nitrate polyether polyol (generic name). ...reporting. (1) The chemical substance nitrate polyether polyol (PMN...

  11. 40 CFR 721.7500 - Nitrate polyether polyol (generic name).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Nitrate polyether polyol (generic name). ...Specific Chemical Substances § 721.7500 Nitrate polyether polyol (generic name). ...reporting. (1) The chemical substance nitrate polyether polyol (PMN...

  12. 40 CFR 721.7500 - Nitrate polyether polyol (generic name).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Nitrate polyether polyol (generic name). ...Specific Chemical Substances § 721.7500 Nitrate polyether polyol (generic name). ...reporting. (1) The chemical substance nitrate polyether polyol (PMN...

  13. 70. INTERIOR VIEW OF AMMONIUM NITRATE HOUSE, LOOKING AT AMMONIUM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    70. INTERIOR VIEW OF AMMONIUM NITRATE HOUSE, LOOKING AT AMMONIUM NITRATE IN STORAGE. APRIL 18, 1919. - United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Muscle Shoals, Colbert County, AL

  14. SAMPLING AND ANALYTICAL METHODOLOGY FOR ATMOSPHERIC PARTICULATE NITRATES

    EPA Science Inventory

    Environmental conditions that affect atmospheric particulate nitrate sampling were identified, and improved sampling and analytical procedures were developed. Evaluation of potential sources of error in high volume nitrate sampling showed that artifact nitrate formation on common...

  15. The contributions of nitrate uptake and efflux to isotope fractionation during algal nitrate assimilation

    NASA Astrophysics Data System (ADS)

    Karsh, K. L.; Trull, T. W.; Sigman, D. M.; Thompson, P. A.; Granger, J.

    2014-05-01

    In order to strengthen environmental application of nitrate N and O isotopes, we measured the N and O isotopic fractionation associated with cellular nitrate uptake and efflux in the nitrate-assimilating marine diatom Thalassiosira weissflogii. We isolated nitrate uptake and efflux from nitrate reduction by growing the cells in the presence of tungsten, which substitutes for molybdenum in assimilatory nitrate reductase, yielding an inactive enzyme. After growth on ammonium and then N starvation, cells were exposed to nitrate. Numerical models fit to the evolution of intracellular nitrate concentration and N and O isotopic composition yielded distinct N isotope effects (15?) for nitrate uptake and nitrate efflux (2.0 ± 0.3‰ and 1.2 ± 0.4‰, respectively). The O isotope effects (18?) for nitrate uptake and nitrate efflux were indistinguishable (2.8 ± 0.6‰), yielding a ratio of O to N isotopic fractionation for uptake of 1.4 ± 0.4 and for efflux of 2.3 ± 0.9. The 15? for nitrate uptake can account for at most 40% of the organism-level N isotope effect (15?org) measured in laboratory studies of T. weissflogii and in the open ocean (typically 5‰ or greater). This observation supports previous evidence that most isotope fractionation during nitrate assimilation is due to intracellular nitrate reduction, with nitrate efflux allowing the signal to be communicated to the environment. An O to N fractionation ratio (18?org:15?org) of ˜1 has been measured for nitrate assimilation in algal cultures and linked to the N and O isotope effects of nitrate reductase. Our results suggest that the ratios of O to N fractionation for both nitrate uptake and efflux may be distinct from a ratio of 1, to a degree that could cause the net 18?org:15?org to rise appreciably above 1 when 15?org is low (e.g., yielding a ratio of 1.1 when 15?org is 5‰). However, field and culture studies have consistently measured nearly equivalent fractionation of N and O isotopes in association with low isotope effects, calling for isotopic studies of nitrate transport by other phytoplankton strains.

  16. Growth of thin zirconium and zirconium oxides films on the n-GaN(0 0 0 1) surface studied by XPS and LEED

    NASA Astrophysics Data System (ADS)

    Idczak, K.; Mazur, P.; Zuber, S.; Markowski, L.; Ski?cim, M.; Bili?ska, S.

    2014-06-01

    This work presents the result of the growth of thin zirconium films on the GaN(0 0 0 1) surface under various conditions. In experiment were used the X-ray photoelectron spectroscopy (XPS) and low-energy electron diffraction (LEED) techniques, which allowed to investigate the chemical composition, bonding environment and surface reconstruction. It is shown that zirconium forms ZrN, ZrNxOy, ZrOx and ZrO2 compounds, depending on the selected experimental conditions: the pressure and annealing temperature. Such a varied zirconium growth behaviour is explained by the diffusion of oxygen and nitrogen in the created interface region.

  17. NITRATE CONTAMINATION OF GROUND WATER (GW-761)

    EPA Science Inventory

    The occurrence of nitrate and related compounds in ground water is discussed from the perspectives of its natural as well as anthropogenic origins. A brief explanation of the nitrogen cycle touches on the production as well as utilization of ammonia, nitrite, nitrate, and nitrog...

  18. 76 FR 46907 - Ammonium Nitrate Security Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-03

    ...This proposed rule would implement anti-terrorism measures to better secure the homeland. The Department of Homeland Security would regulate the sale and transfer of ammonium nitrate pursuant to section 563 of the Fiscal Year 2008 Department of Homeland Security Appropriations Act with the purpose of preventing the use of ammonium nitrate in an act of terrorism. This proposed rule seeks......

  19. 76 FR 62311 - Ammonium Nitrate Security Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-07

    ... FR 64280 (advance notice of proposed rulemaking); 76 FR 46908 (notice of proposed rulemaking... Program Web site in mid-October at http://www.dhs.gov/ files/ ] programs/ammonium-nitrate-security-program...; ] DEPARTMENT OF HOMELAND SECURITY Office of the Secretary 6 CFR Part 31 RIN 1601-AA52 Ammonium Nitrate...

  20. COMPARTMENTAL MODEL OF NITRATE RETENTION IN STREAMS

    EPA Science Inventory

    A compartmental modeling approach is presented to route nitrate retention along a cascade of stream reach sections. A process transfer function is used for transient storage equations with first order reaction terms to represent nitrate uptake in the free stream, and denitrifica...

  1. Nitrates and Prussic Acid in Forages 

    E-print Network

    Provin, Tony; Pitt, John L.

    2003-01-06

    When nitrates and prussic acid accumulate in forage, the feed may not be safe for livestock consumption. Learn the symptoms of nitrate and prussic acid poisoning and which plants are most likely to pose a risk to livestock. Also learn sampling...

  2. HEALTH EFFECTS OF NITRATES IN WATER

    EPA Science Inventory

    A multi faceted study of the health effects of nitrate in drinking water using epidemiological and toxicological techniques is reported. The results of the epidemiological studies indicate that infants consuming appreciable amounts of water high in nitrates in the form of powdere...

  3. Spatial Inference of Nitrate Concentrations in Groundwater

    E-print Network

    Woodard, Dawn B.

    measurements at a set of locations. We apply this method to obtain inferences for nitrates in groundwater overSpatial Inference of Nitrate Concentrations in Groundwater DAWN B. WOODARD, ROBERT L. WOLPERT in groundwater over the mid-Atlantic states, using measurements gathered during a pe- riod of ten years. A map

  4. Nitrate removal from drinking water -- Review

    SciTech Connect

    Kapoor, A.; Viraraghavan, T.

    1997-04-01

    Nitrate concentrations in surface water and especially in ground water have increased in Canada, the US, Europe, and other areas of the world. This trend has raised concern because nitrates cause methemoglobiinemia in infants. Several treatment processes including ion exchange, biological denitrification, chemical denitrification, reverse osmosis, electrodialysis, and catalytic denitrification can remove nitrates from water with varying degrees of efficiency, cost, and ease of operation. Available technical data, experience, and economics indicate that ion exchange and biological denitrification are more acceptable for nitrate removal than reverse osmosis. Ion exchange is more viable for ground water while biological denitrification is the preferred alternative for surface water. This paper reviews the developments in the field of nitrate removal processes.

  5. Use of nitrates in ischemic heart disease.

    PubMed

    Giuseppe, Cocco; Paul, Jerie; Hans-Ulrich, Iselin

    2015-01-01

    Short-acting nitrates are beneficial in acute myocardial ischemia. However, many unresolved questions remain about the use of long-acting nitrates in stable ischemic heart disease. The use of long-acting nitrates is weakened by the development of endothelial dysfunction and tolerance. Also, we currently ignore whether lower doses of transdermal nitroglycerin would be better than those presently used. Multivariate analysis data from large nonrandomized studies suggested that long-acting nitrates increase the incidence of acute coronary syndromes, while data from another multivariate study indicate that they have positive effects. Because of methodological differences and open questions, the two studies cannot be compared. A study in Japanese patients with vasospastic angina has shown that, when compared with calcium antagonists, long-acting nitrates do not improve long-term prognosis and that the risk for cardiac adverse events increases with the combined therapy. We have many unanswered questions. PMID:26027641

  6. Solid-state coexistence of {Zr12} and {Zr6} zirconium oxocarboxylate clusters

    SciTech Connect

    Malaestean, Iurie L.; Alici, Meliha Kutluca; Besson, Claire; Ellern, Arkady; Kogerler, Paul

    2013-10-30

    Ligand metathesis, Co(II) coordination, and partial condensation reactions of an archetypal {Zr6} zirconium oxocarboxylate cluster result in the first example of the coexistence of the distinct zirconium oxide frameworks {Zr6O8} and {Zr12O22}. Even minor modifications to the reaction conditions push this apparent equilibrium towards the {Zr6O8}-based product.

  7. Solid-State Coexistance of (Zr12) and (Zr6) Zirconium Oxocarboxylate Clusters

    SciTech Connect

    Malaestean, Lurie; Alici, Meliha Kutluca; Besson, Claire; Ellern, Arkady; Kogerler, Paul

    2013-10-30

    Ligand metathesis, Co(II) coordination, and partial condensation reactions of an archetypal {Zr6} zirconium oxocarboxylate cluster result in the first example of the coexistence of the distinct zirconium oxide frameworks {Zr6O8} and {Zr12O22}. Even minor modifications to the reaction conditions push this apparent equilibrium towards the {Zr6O8}-based product.

  8. Lithium aluminate/zirconium material useful in the production of tritium

    DOEpatents

    Cawley, W.E.; Trapp, T.J.

    1984-10-09

    A composition is described useful in the production of tritium in a nuclear reactor. Lithium aluminate particles are dispersed in a matrix of zirconium. Tritium produced by the reactor of neutrons with the lithium are absorbed by the zirconium, thereby decreasing gas pressure within capsules carrying the material.

  9. Zirconium carbide as an electrocatalyst for the chromous-chromic redox couple

    NASA Technical Reports Server (NTRS)

    Gahn, R. F.; Reid, M. A.; Yang, C. Y. (inventors)

    1981-01-01

    Zirconium carbide is used as a catalyst in a REDOX cell for the oxidation of chromous ions to chromic ions and for the reduction of chromic ions to chromous ions. The zirconium carbide is coated on an inert electronically conductive electrode which is present in the anode fluid of the cell.

  10. 21 CFR 700.16 - Use of aerosol cosmetic products containing zirconium.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 7 2011-04-01 2010-04-01 true Use of aerosol cosmetic products containing... SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.16 Use of aerosol cosmetic products containing zirconium. (a) Zirconium-containing complexes have been used as an...

  11. 21 CFR 700.16 - Use of aerosol cosmetic products containing zirconium.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 7 2014-04-01 2014-04-01 false Use of aerosol cosmetic products containing... SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.16 Use of aerosol cosmetic products containing zirconium. (a) Zirconium-containing complexes have been used as an...

  12. 21 CFR 700.16 - Use of aerosol cosmetic products containing zirconium.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Use of aerosol cosmetic products containing... SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.16 Use of aerosol cosmetic products containing zirconium. (a) Zirconium-containing complexes have been used as an...

  13. 21 CFR 700.16 - Use of aerosol cosmetic products containing zirconium.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 7 2012-04-01 2012-04-01 false Use of aerosol cosmetic products containing... SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.16 Use of aerosol cosmetic products containing zirconium. (a) Zirconium-containing complexes have been used as an...

  14. 21 CFR 700.16 - Use of aerosol cosmetic products containing zirconium.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 7 2013-04-01 2013-04-01 false Use of aerosol cosmetic products containing... SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.16 Use of aerosol cosmetic products containing zirconium. (a) Zirconium-containing complexes have been used as an...

  15. In situ ion irradiation of zirconium carbide Christopher J. Ulmer a, *

    E-print Network

    Motta, Arthur T.

    as the load-bearing layer in TRISO fuel for a VHTR, the response of ZrC to radiation damage must be understood Accepted 5 August 2015 Available online 10 August 2015 Keywords: Nuclear materials Zirconium carbide Ion irradiation Defects a b s t r a c t Zirconium carbide (ZrC) is a candidate material for use in one

  16. Global distribution of peroxyacetyl nitrate

    NASA Technical Reports Server (NTRS)

    Singh, H. B.; Salas, L. J.; Viezee, W.

    1986-01-01

    Peroxyacetyl nitrate (PAN) atmospheric concentration samples were collected hourly from an ocean vessel 50 mi off the continental coast traveling from Seattle to Chile in 1984. Air concentration data for PAN and light hydrocarbons (LHC) were also taken by aircraft in the same period over Wyoming and Colorado and over the eastern Pacific. The PAN concentrations were higher and more variable in the Northern Hemisphere than in the Southern Hemisphere, increased with altitude, and were higher in the winter than in summer. The summer PAN concentrations were higher in the continental troposphere than in the marine troposphere. The results show that photochemical models of the atmosphere which do not account for the reaction between nonmethane hydrocarbons and PAN will probably overestimate the abundances of NO(x) and HNO3. The collection of further PAN concentration data is recommended as a means to characterizing the moderating role of PAN in the photochemistry of the troposphere.

  17. Predicting the equilibria of point defects in zirconium oxide : a route to understand the corrosion and hydrogen pickup of zirconium alloys

    E-print Network

    Youssef, Mostafa Youssef Mahmoud

    2014-01-01

    The performance of zirconium alloys in nuclear reactors is compromised by corrosion and hydrogen pickup. The thermodynamics and kinetics of these two processes are governed by the behavior of point defects in the ZrO? layer ...

  18. A simple spectrophotometric method for determination of zirconium or hafnium in selected molybdenum-base alloys

    NASA Technical Reports Server (NTRS)

    Dupraw, W. A.

    1972-01-01

    A simple analytical procedure is described for accurately and precisely determining the zirconium or hafnium content of molybdenum-base alloys. The procedure is based on the reaction of the reagent Arsenazo III with zirconium or hafnium in strong hydrochloric acid solution. The colored complexes of zirconium or hafnium are formed in the presence of molybdenum. Titanium or rhenium in the alloy have no adverse effect on the zirconium or hafnium complex at the following levels in the selected aliquot: Mo, 10 mg; Re, 10 mg; Ti, 1 mg. The spectrophotometric measurement of the zirconium or hafnium complex is accomplished without prior separation with a relative standard deviation of 1.3 to 2.7 percent.

  19. Modeling nitrate removal in a denitrification bed.

    PubMed

    Ghane, Ehsan; Fausey, Norman R; Brown, Larry C

    2015-03-15

    Denitrification beds are promoted to reduce nitrate load in agricultural subsurface drainage water to alleviate the adverse environmental effects associated with nitrate pollution of surface water. In this system, drainage water flows through a trench filled with a carbon media where nitrate is transformed into nitrogen gas under anaerobic conditions. The main objectives of this study were to model a denitrification bed treating drainage water and evaluate its adverse greenhouse gas emissions. Field experiments were conducted at an existing denitrification bed. Evaluations showed very low greenhouse gas emissions (mean N2O emission of 0.12 ?g N m(-2) min(-1)) from the denitrification bed surface. Field experiments indicated that nitrate removal rate was described by Michaelis-Menten kinetics with the Michaelis-Menten constant of 7.2 mg N L(-1). We developed a novel denitrification bed model based on the governing equations for water flow and nitrate removal kinetics. The model evaluation statistics showed satisfactory prediction of bed outflow nitrate concentration during subsurface drainage flow. The model can be used to design denitrification beds with efficient nitrate removal which in turn leads to enhanced drainage water quality. PMID:25638338

  20. Plasma sprayed and electrospark deposited zirconium metal diffusion barrier coatings

    SciTech Connect

    Hollis, Kendall J; Pena, Maria I

    2010-01-01

    Zirconium metal coatings applied by plasma spraying and electrospark deposition (ESD) have been investigated for use as diffusion barrier coatings on low enrichment uranium fuel for research nuclear reactors. The coatings have been applied to both stainless steel as a surrogate and to simulated nuclear fuel uranium-molybdenum alloy substrates. Deposition parameter development accompanied by coating characterization has been performed. The structure of the plasma sprayed coating was shown to vary with transferred arc current during deposition. The structure of ESD coatings was shown to vary with the capacitance of the deposition equipment.

  1. Polymerization of norbornene using chiral bis(phenolate) zirconium catalysts.

    PubMed

    Tschage, Marie; Jung, Seungwhan; Spaniol, Thomas P; Okuda, Jun

    2015-01-01

    Norbornene is polymerized by employing zirconium catalysts with (OSSO)-type bis(phenolate) ligands. The racemic precatalyst rac-1 produces high molecular weight poly(norbornene) with slight optical activity. Enantiopure precatalysts (S,S)-1 and (R,R)-1 are used to study the optical induction in the poly(norbornene)s formed. To overcome the insolubility of poly(norbornene)s in common solvents, their microstructure is studied using copolymers with ethylene as well as hydrooligomers. The crystal structure of a norbornene tetramer is reported. PMID:25271141

  2. Minerals yearbook, 1991: Zirconium and hafnium. Annual report

    SciTech Connect

    Templeton, D.A.

    1993-03-01

    Mr. Templeton is a physical scientist with the Branch of Industrial Minerals. He has covered zirconium and hafnium for about 4 years. Domestic survey data were prepared by the Section of Metals Data. World production data are provided by country specialists in the Division of International Minerals, and the data were compiled by Mr. Harold D. Willis. Data in the report are collected from an assortment of sources. U.S. mine production of zircon sand is obtained by directly surveying the three producing mines, all of which responded.

  3. Zirconium(IV) dilanthanum(III) penta­sulfide

    PubMed Central

    Raw, Adam D.; Ibers, James A.

    2011-01-01

    Zirconium(IV) dilanthanum(III) penta­sulfide, ZrLa2S5, crystallizes with four formula units in the space group Pnma in the U3S5 structure type. The asymmetric unit comprises one Zr, one La and four S atoms. The Zr and three S atoms are situated on mirror planes. The structure consists of LaS8 face-sharing bicapped distorted trigonal prisms and ZrS7 edge-sharing monocapped octa­hedra. PMID:22199468

  4. Photodegradation of Paracetamol in Nitrate Solution

    SciTech Connect

    Meng Cui; Qu Ruijuan; Liang Jinyan; Yang Xi

    2010-11-24

    The photodegradation of paracetamol in nitrate solution under simulated solar irradiation has been investigated. The degradation rates were compared by varying environmental parameters including concentrations of nitrate ion, humic substance and pH values. The quantifications of paracetamol were conducted by HPLC method. The results demonstrate that the photodegradation of paracetamol followed first-order kinetics. The photoproducts and intermediates of paracetamol in the presence of nitrate ions were identified by extensive GC-MS method. The photodegradation pathways involving. OH radicals as reactive species were proposed.

  5. Electrophilic and free radical nitration of benzene and toluene with various nitrating agents*

    PubMed Central

    Olah, George A.; Lin, Henry C.; Olah, Judith A.; Narang, Subhash C.

    1978-01-01

    Electrophilic nitration of toluene and benzene was studied under various conditions with several nitrating systems. It was found that high orthopara regioselectivity is prevalent in all reactions and is independent of the reactivity of the nitrating agent. The methyl group of toluene is predominantly ortho-para directing under all reaction conditions. Steric factors are considered to be important but not the sole reason for the variation in the ortho/para ratio. The results reinforce our earlier views that, in electrophilic aromatic nitrations with reactive nitrating agents, substrate and positional selectivities are determined in two separate steps. The first step involves a ?-aromatic-NO2+ ion complex or encounter pair, whereas the subsequent step is of arenium ion nature (separate for the ortho, meta, and para positions). The former determines substrate selectivity, whereas the latter determines regioselectivity. Thermal free radical nitration of benzene and toluene with tetranitromethane in sharp contrast gave nearly statistical product distributions. PMID:16592503

  6. Grafco Silver Nitrate Applicators Page 1 of 5

    E-print Network

    Wikswo, John

    Grafco® Silver Nitrate Applicators Rev. D Page 1 of 5 MATERIAL SAFETY DATA SHEET 1.0 IDENTIFICATION Product: Grafco® SILVER NITRATE General Use: Cauterization of wounds and APPLICATORS ulcers Manufacturers.0 Hazard(s) Identification EMERGENCY OVERVIEW: Silver nitrate/potassium nitrate solid impregnated on tip

  7. The distribution of nitrate 15 N in marine sediments

    E-print Network

    Sigman, Daniel M.

    The distribution of nitrate 15 N/14 N in marine sediments and the impact of benthic nitrogen loss on the isotopic composition of oceanic nitrate Moritz F. Lehmann a,*, Daniel M. Sigman b , Daniel C. McCorkle c 15 N/14 N ratios of porewater nitrate in sediments from the Bering Sea basin, where microbial nitrate

  8. Original Articles Cytometric Quantification of Nitrate Reductase by

    E-print Network

    Jochem, Frank J.

    Original Articles Cytometric Quantification of Nitrate Reductase by Immunolabeling in the Marine November 1999; Accepted 24 November 1999 Background: The uptake of nitrate by phytoplankton is a central of biogenic carbon. Nitrate reductase catalyzes the first step of nitrate assimilation, the reduction of NO3

  9. Qualitative Determination of Nitrate with Triphenylbenzylphosphonium Chloride.

    ERIC Educational Resources Information Center

    Berry, Donna A.; Cole, Jerry J.

    1984-01-01

    Discusses two procedures for the identification of nitrate, the standard test ("Brown Ring" test) and a new procedure using triphenylbenzylphosphonium chloride (TPBPC). Effectiveness of both procedures is compared, with the TPBPC test proving to be more sensitive and accurate. (JM)

  10. Phase diagram of ammonium nitrate

    SciTech Connect

    Dunuwille, Mihindra; Yoo, Choong-Shik

    2013-12-07

    Ammonium Nitrate (AN) is a fertilizer, yet becomes an explosive upon a small addition of chemical impurities. The origin of enhanced chemical sensitivity in impure AN (or AN mixtures) is not well understood, posing significant safety issues in using AN even today. To remedy the situation, we have carried out an extensive study to investigate the phase stability of AN and its mixtures with hexane (ANFO–AN mixed with fuel oil) and Aluminum (Ammonal) at high pressures and temperatures, using diamond anvil cells (DAC) and micro-Raman spectroscopy. The results indicate that pure AN decomposes to N{sub 2}, N{sub 2}O, and H{sub 2}O at the onset of the melt, whereas the mixtures, ANFO and Ammonal, decompose at substantially lower temperatures. The present results also confirm the recently proposed phase IV-IV{sup ?} transition above 17 GPa and provide new constraints for the melting and phase diagram of AN to 40 GPa and 400°C.

  11. Peroxyacetyl nitrate in eastern Scotland.

    PubMed

    McFadyen, G G; Cape, J N

    2005-01-20

    Peroxyacetyl nitrate (PAN) concentrations in air were sampled hourly from 1994 to 1998 at a rural site 15 km south-west of Edinburgh, in eastern Scotland. Annual average concentrations were between 0.1 and 0.15 nl l(-1), with episodes up to 3 nl l(-1) in long-range transported polluted air. PAN concentrations were approximately log-normally distributed. The concentrations measured are the result of a balance between photochemical production rates and removal by thermal decomposition and dry deposition. In general, there was a poor correlation between PAN and ozone concentrations at this rural site except during episodes of photochemical pollution, when the PAN/O(3) volume ratio exceeded 0.01. The PAN/NO(x) volume ratio had a median value of 0.015 but ranged up to 0.25. There was a pronounced seasonal maximum in PAN concentrations in late spring, and a strong diurnal cycle only in April-June, with a maximum at 1700 h. Individual episodes, with concentrations up to 3 nl l(-1), could be traced over distances of ca. 1000 km, with rapid changes in concentration as the prevailing winds advected polluted air masses across the site. PMID:15626392

  12. Synthesis of a new energetic nitrate ester

    SciTech Connect

    Chavez, David E

    2008-01-01

    Nitrate esters have been known as useful energetic materials since the discovery of nitroglycerin by Ascanio Sobrero in 1846. The development of methods to increase the safety and utility of nitroglycerin by Alfred Nobel led to the revolutionary improvement in the utility of nitroglycerin in explosive applications in the form of dynamite. Since then, many nitrate esters have been prepared and incorporated into military applications such as double-based propellants, detonators and as energetic plasticizers. Nitrate esters have also been shown to have vasodilatory effects in humans and thus have been studied and used for treatments of ailments such as angina. The mechanism of the biological response towards nitrate esters has been elucidated recently. Interestingly, many of the nitrate esters used for military purposes are liquids (ethylene glycol dinitrate, propylene glycol dinitrate, etc). Pentaerythritol tetranitrate (PETN) is one of the only solid nitrate esters, besides nitrocellulose, that is used in any application. Unfortunately, PETN melting point is above 100 {sup o}C, and thus must be pressed as a solid for detonator applications. A more practical material would be a melt-castable explosive, for potential simplification of manufacturing processes. Herein we describe the synthesis of a new energetic nitrate ester (1) that is a solid at ambient temperatures, has a melting point of 85-86 {sup o}C and has the highest density of any known nitrate ester composed only of carbon, hydrogen, nitrogen and oxygen. We also describe the chemical, thermal and sensitivity properties of 1 as well as some preliminary explosive performance data.

  13. The UK Nitrate Time Bomb (Invited)

    NASA Astrophysics Data System (ADS)

    Ward, R.; Wang, L.; Stuart, M.; Bloomfield, J.; Gooddy, D.; Lewis, M.; McKenzie, A.

    2013-12-01

    The developed world has benefitted enormously from the intensification of agriculture and the increased availability and use of synthetic fertilizers during the last century. However there has also been unintended adverse impact on the natural environment (water and ecosystems) with nitrate the most significant cause of water pollution and ecosystem damage . Many countries have introduced controls on nitrate, e.g. the European Union's Water Framework and Nitrate Directives, but despite this are continuing to see a serious decline in water quality. The purpose of our research is to investigate and quantify the importance of the unsaturated (vadose) zone pathway and groundwater in contributing to the decline. Understanding nutrient behaviour in the sub-surface environment and, in particular, the time lag between action and improvement is critical to effective management and remediation of nutrient pollution. A readily-transferable process-based model has been used to predict temporal loading of nitrate at the water table across the UK. A time-varying nitrate input function has been developed based on nitrate usage since 1925. Depth to the water table has been calculated from groundwater levels based on regional-scale observations in-filled by interpolated river base levels and vertical unsaturated zone velocities estimated from hydrogeological properties and mapping. The model has been validated using the results of more than 300 unsaturated zone nitrate profiles. Results show that for about 60% of the Chalk - the principal aquifer in the UK - peak nitrate input has yet to reach the water table and concentrations will continue to rise over the next 60 years. The implications are hugely significant especially where environmental objectives must be achieved in much shorter timescales. Current environmental and regulatory management strategies rarely take lag times into account and as a result will be poorly informed, leading to inappropriate controls and conflicts between policy makers, environmentalists and industry.

  14. Zirconium speciation in lactate solutions and polyacrylate gels.

    PubMed

    Rose, J; Chauveteau, G; Tabary, R; Renard, M; Omari, A; Toulhoat, H

    2001-03-01

    Controlling gelation kinetics is an important objective for several applications (ceramic and thin film syntheses, reduction in permeability of porous rock, etc). There is a growing interest in studying the gelation of polymers by zirconium, a crosslinker of lower toxicity than the chromium which is still commonly used. XAS at the Zr K-edge was performed at the European Synchrotron Radiation Facility (ESRF) on the BM32 beamline. The fluorescence detection was used to carry out successful in situ speciation at concentrations as low as 36 ppm. The Zr speciation was determined both in ZrLa (where La stands for lactate) aqueous solutions and in gels of a terpolymer of acrylamide having 2% of zirconium reactive acrylate side groups and 2% of sulfonate groups introduced to prevent syneresis. XANES results show that Zr is always in a dodecahedral geometry. In ZrLa solutions. EXAFS results indicate that Zr species grow from a dimer Zr2(La)6 to a tetramer (Zr4(La)x) and then to larger polymers resulting from tetramer associations, as the Zr concentration decreases from 51840 ppm to 36ppm. In polymer gels, Zr species appear to be dimers at pH 6 while tetramers are found when gelation occurred at pH 7. Calculations taking into account multiple scattering effects as well as dynamic molecular calculation confirmed conclusions derived from conventional EXAFS analysis. PMID:11512896

  15. Green strength of zirconium sponge and uranium dioxide powder compacts

    SciTech Connect

    Balakrishna, Palanki Murty, B. Narasimha; Sahoo, P.K.; Gopalakrishna, T.

    2008-07-15

    Zirconium metal sponge is compacted into rectangular or cylindrical shapes using hydraulic presses. These shapes are stacked and electron beam welded to form a long electrode suitable for vacuum arc melting and casting into solid ingots. The compact electrodes should be sufficiently strong to prevent breakage in handling as well as during vacuum arc melting. Usually, the welds are strong and the electrode strength is limited by the green strength of the compacts, which constitute the electrode. Green strength is also required in uranium dioxide (UO{sub 2}) powder compacts, to withstand stresses during de-tensioning after compaction as well as during ejection from the die and for subsequent handling by man and machine. The strengths of zirconium sponge and UO{sub 2} powder compacts have been determined by bending and crushing respectively, and Weibul moduli evaluated. The green density of coarse sponge compact was found to be larger than that from finer sponge. The green density of compacts from lightly attrited UO{sub 2} powder was higher than that from unattrited category, accompanied by an improvement in UO{sub 2} green crushing strength. The factors governing green strength have been examined in the light of published literature and experimental evidence. The methodology and results provide a basis for quality control in metal sponge and ceramic powder compaction in the manufacture of nuclear fuel.

  16. Layered zirconium phosphonate with inorganic-organic hybrid structure: Preparation and its assembly with DNA

    NASA Astrophysics Data System (ADS)

    Liu, Li-Min; Lu, Guo-Yuan; Jiang, Li-Ping; Zhu, Jun-Jie

    2014-07-01

    An aminoethoxy-functionalized zirconium phosphonate (Zr(O3POCH2CH2NH2)2·3H2O), abbreviated as ZrRP (R=OCH2CH2NH2), with layered structure has been synthesized. This layered compound possesses the characteristic of inorganic-organic hybrid, due to the covalently linked aminoethoxy in the host layer. The anion exchanged property of this zirconium phosphonate is suitable for the direct intercalation of negatively charged DNA, which is different from these reported zirconium phosphates or zirconium phosphonates. As a precursor, this prepared zirconium phosphonate was utilized to fabricate a novel DNA/ZrRP binary hybrid via a delamination-reassembly procedure. The release behavior of DNA from the DNA/ZrRP composite was investigated at different medium pH, because the combination between zirconium phosphonate sheets and DNA was pH-dependent sensitively. Moreover, the helical conformation of DNA was almost retained after the intercalation and release process. These properties of the DNA/ZrRP composite suggested the potential application of layered zirconium phosphonate as a non-viral vector in gene delivery.

  17. Protein tyrosine nitration in the cell cycle

    SciTech Connect

    Jia, Min; Mateoiu, Claudia; Souchelnytskyi, Serhiy

    2011-09-23

    Highlights: {yields} Enrichment of 3-nitrotyrosine containing proteins from cells synchronized in different phases of the cell cycle. {yields} Identification of 76 tyrosine nitrated proteins that change expression during the cell cycle. {yields} Nineteen identified proteins were previously described as regulators of cell proliferation. -- Abstract: Nitration of tyrosine residues in proteins is associated with cell response to oxidative/nitrosative stress. Tyrosine nitration is relatively low abundant post-translational modification that may affect protein functions. Little is known about the extent of protein tyrosine nitration in cells during progression through the cell cycle. Here we report identification of proteins enriched for tyrosine nitration in cells synchronized in G0/G1, S or G2/M phases of the cell cycle. We identified 27 proteins in cells synchronized in G0/G1 phase, 37 proteins in S phase synchronized cells, and 12 proteins related to G2/M phase. Nineteen of the identified proteins were previously described as regulators of cell proliferation. Thus, our data indicate which tyrosine nitrated proteins may affect regulation of the cell cycle.

  18. Process for decomposing nitrates in aqueous solution

    DOEpatents

    Haas, Paul A. (Knoxville, TN)

    1980-01-01

    This invention is a process for decomposing ammonium nitrate and/or selected metal nitrates in an aqueous solution at an elevated temperature and pressure. Where the compound to be decomposed is a metal nitrate (e.g., a nuclear-fuel metal nitrate), a hydroxylated organic reducing agent therefor is provided in the solution. In accordance with the invention, an effective proportion of both nitromethane and nitric acid is incorporated in the solution to accelerate decomposition of the ammonium nitrate and/or selected metal nitrate. As a result, decomposition can be effected at significantly lower temperatures and pressures, permitting the use of system components composed of off-the-shelf materials, such as stainless steel, rather than more costly materials of construction. Preferably, the process is conducted on a continuous basis. Fluid can be automatically vented from the reaction zone as required to maintain the operating temperature at a moderate value--e.g., at a value in the range of from about 130.degree.-200.degree. C.

  19. Suppression of erythropoiesis by dietary nitrate.

    PubMed

    Ashmore, Tom; Fernandez, Bernadette O; Evans, Colin E; Huang, Yun; Branco-Price, Cristina; Griffin, Julian L; Johnson, Randall S; Feelisch, Martin; Murray, Andrew J

    2015-03-01

    In mammals, hypoxia-triggered erythropoietin release increases red blood cell mass to meet tissue oxygen demands. Using male Wistar rats, we unmask a previously unrecognized regulatory pathway of erythropoiesis involving suppressor control by the NO metabolite and ubiquitous dietary component nitrate. We find that circulating hemoglobin levels are modulated by nitrate at concentrations achievable by dietary intervention under normoxic and hypoxic conditions; a moderate dose of nitrate administered via the drinking water (7 mg NaNO3/kg body weight/d) lowered hemoglobin concentration and hematocrit after 6 d compared with nonsupplemented/NaCl-supplemented controls. The underlying mechanism is suppression of hepatic erythropoietin expression associated with the downregulation of tissue hypoxia markers, suggesting increased pO2. At higher nitrate doses, however, a partial reversal of this effect occurred; this was accompanied by increased renal erythropoietin expression and stabilization of hypoxia-inducible factors, likely brought about by the relative anemia. Thus, hepatic and renal hypoxia-sensing pathways act in concert to modulate hemoglobin in response to nitrate, converging at an optimal minimal hemoglobin concentration appropriate to the environmental/physiologic situation. Suppression of hepatic erythropoietin expression by nitrate may thus act to decrease blood viscosity while matching oxygen supply to demand, whereas renal oxygen sensing could act as a brake, averting a potentially detrimental fall in hematocrit. PMID:25422368

  20. Origin of the deep Bering Sea nitrate deficit: Constraints from the nitrogen and oxygen isotopic composition of water column nitrate

    E-print Network

    Sigman, Daniel M.

    Origin of the deep Bering Sea nitrate deficit: Constraints from the nitrogen and oxygen isotopic composition of water column nitrate and benthic nitrate fluxes Moritz F. Lehmann,1,2 Daniel M. Sigman,1 Daniel. [1] On the basis of the normalization to phosphate, a significant amount of nitrate is missing from

  1. Effect of nano-sized cerium-zirconium oxide solid solution on far-infrared emission properties of tourmaline powders

    NASA Astrophysics Data System (ADS)

    Guo, Bin; Yang, Liqing; Hu, Weijie; Li, Wenlong; Wang, Haojing

    2015-10-01

    Far-infrared functional nanocomposites were prepared by the co-precipitation method using natural tourmaline (XY3Z6Si6O18(BO3)3V3W, where X is Na+, Ca2+, K+, or vacancy; Y is Mg2+, Fe2+, Mn2+, Al3+, Fe3+, Mn3+, Cr3+, Li+, or Ti4+; Z is Al3+, Mg2+, Cr3+, or V3+; V is O2?, OH?; and W is O2?, OH?, or F?) powders, ammonium cerium(IV) nitrate and zirconium(IV) nitrate pentahydrate as raw materials. The reference sample, tourmaline modified with ammonium cerium(IV) nitrate alone was also prepared by a similar precipitation route. The results of Fourier transform infrared spectroscopy show that tourmaline modified with Ce and Zr has a better far-infrared emission property than tourmaline modified with Ce alone. Through characterization by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), the mechanism for oxygen evolution during the heat process in the two composite materials was systematically studied. The XPS spectra show that Fe3+ ratio inside tourmaline modified with Ce alone can be raised by doping Zr. Moreover, it is showed that there is a higher Ce3+ ratio inside the tourmaline modified with Ce and Zr than tourmaline modified with Ce alone. In addition, XRD results indicate the formation of CeO2 and Ce1?xZrxO2 crystallites during the heat treatment and further TEM observations show they exist as nanoparticles on the surface of tourmaline powders. Based on these results, we attribute the improved far-infrared emission properties of Ce-Zr doped tourmaline to the enhanced unit cell shrinkage of the tourmaline arisen from much more oxidation of Fe2+ to Fe3+ inside the tourmaline caused by the change in the catalyst redox properties of CeO2 brought about by doping with Zr4+. In all samples, tourmaline modified with 7.14 wt.% Ce and 1.86 wt.% Zr calcined at 800?C for 5 h has the best far-infrared emission property with the maximum emissivity value of 98%.

  2. Organic Nitrate Therapy, Nitrate Tolerance, and Nitrate-Induced Endothelial Dysfunction: Emphasis on Redox Biology and Oxidative Stress.

    PubMed

    Daiber, Andreas; Münzel, Thomas

    2015-10-10

    Organic nitrates, such as nitroglycerin (GTN), isosorbide-5-mononitrate and isosorbide dinitrate, and pentaerithrityl tetranitrate (PETN), when given acutely, have potent vasodilator effects improving symptoms in patients with acute and chronic congestive heart failure, stable coronary artery disease, acute coronary syndromes, or arterial hypertension. The mechanisms underlying vasodilation include the release of (•)NO or a related compound in response to intracellular bioactivation (for GTN, the mitochondrial aldehyde dehydrogenase [ALDH-2]) and activation of the enzyme, soluble guanylyl cyclase. Increasing cyclic guanosine-3',-5'-monophosphate (cGMP) levels lead to an activation of the cGMP-dependent kinase I, thereby causing the relaxation of the vascular smooth muscle by decreasing intracellular calcium concentrations. The hemodynamic and anti-ischemic effects of organic nitrates are rapidly lost upon long-term (low-dose) administration due to the rapid development of tolerance and endothelial dysfunction, which is in most cases linked to increased intracellular oxidative stress. Enzymatic sources of reactive oxygen species under nitrate therapy include mitochondria, NADPH oxidases, and an uncoupled (•)NO synthase. Acute high-dose challenges with organic nitrates cause a similar loss of potency (tachyphylaxis), but with distinct pathomechanism. The differences among organic nitrates are highlighted regarding their potency to induce oxidative stress and subsequent tolerance and endothelial dysfunction. We also address pleiotropic effects of organic nitrates, for example, their capacity to stimulate antioxidant pathways like those demonstrated for PETN, all of which may prevent adverse effects in response to long-term therapy. Based on these considerations, we will discuss and present some preclinical data on how the nitrate of the future should be designed. Antioxid. Redox Signal. 23, 899-942. PMID:26261901

  3. Nitrate in groundwater in the United States

    NASA Astrophysics Data System (ADS)

    Burow, K. R.; Nolan, B. T.; Rupert, M. G.; Dubrovsky, N. M.

    2009-12-01

    An assessment of nitrate concentrations in groundwater in the United States (US) indicates that concentrations are highest in shallow, oxic groundwater beneath areas with high nitrogen inputs. During 1991-2003, 5,101 wells were sampled in 51 study areas throughout the US as part of the USGS National Water-Quality Assessment program. Well locations for individual 30-well networks were selected for sampling using a computerized, stratified, random site-selection procedure to minimize spatial bias. These well networks reflect the existing used resource in major aquifers represented by domestic wells (major aquifer studies), and recently recharged groundwater beneath dominant land-surface activities (land-use studies). Nitrate concentrations in groundwater were compared with nationally-available variables such as nonpoint-source nitrogen inputs, soils, water chemistry, and other aquifer and well construction characteristics to predict the conditions most vulnerable to high nitrate concentrations. Nitrate was detected at concentrations above background of 1.0 mg/L (as N) in 50% of the wells sampled. Shallow groundwater beneath agricultural land had the highest median concentration of nitrate (3.1 mg/L). Median nitrate in shallow groundwater beneath urban land (1.4 mg/L) was lower than beneath agricultural land, but was higher than the median in major aquifers (0.56 mg/L). Although most wells sampled in the shallow land-use studies were not used for drinking water, concentrations exceeded the US EPA drinking-water standard (MCL) of 10 mg/L in 20% of wells in the agricultural land-use setting. Concentrations exceeded the MCL in only 3% of wells in the urban land-use setting, and 4% of wells in major aquifers. Classification and regression tree analysis was used to identify the relative importance of nitrogen inputs, water chemistry, and physical aquifer properties on nitrate concentrations in groundwater. Factors ranked by reduction in sum of squares indicate that dissolved iron concentrations explained most of the variation in groundwater nitrate concentration, followed by manganese, calcium, farm fertilizer, percent well-drained soils, dissolved oxygen, and other chemical and physical factors. The high rankings of iron, manganese, and farm fertilizer indicate that nitrate concentrations in groundwater are most significantly affected by redox conditions and nonpoint-source nitrogen inputs. The other water-quality indicators and physical variables have a secondary influence on nitrate concentrations.

  4. Nitration of naphthalene and remarks on the mechanism of electrophilic aromatic nitration*

    PubMed Central

    Olah, George A.; Narang, Subhash C.; Olah, Judith A.

    1981-01-01

    Naphthalene was nitrated with a variety of nitrating agents. Comparison of data with Perrin's electrochemical nitration [Perrin, C. L. (1977) J. Am. Chem. Soc. 99, 5516-5518] shows that nitration of naphthalene gives an ?-nitronaphthalene to ?-nitronaphthalene ratio that varies between 9 and 29 and is thus not constant. Perrin's data, therefore, are considered to be inconclusive evidence for the proposed one-electron transfer mechanism for the nitration of naphthalene and other reactive aromatics. Moodie and Schoefield [Hoggett, J. G., Moodie, R. B., Penton, J. R. & Schoefield, K. (1971) Nitration and Aromatic Reactivity (Cambridge Univ. Press, London)], as well as Perrin, independently concluded that, in the general scheme of nitration of reactive aromatics, there is the necessity to introduce into the classical Ingold mechanism an additional step involving a distinct intermediate preceding the formation of the Wheland intermediate (? complexes). This view coincides with our two-step mechanistic picture [Kuhn, S. J. & Olah, G. A. (1961) J. Am. Chem. Soc. 83, 4564-4571] of the nitronium salt nitration of aromatic hydrocarbons (including benzene and toluene), in which low substrate selectivity but high positional selectivity was found, indicating the independence of substrate from positional selectivity. PMID:16593026

  5. Nitration of naphthalene and remarks on the mechanism of electrophilic aromatic nitration.

    PubMed

    Olah, G A; Narang, S C; Olah, J A

    1981-06-01

    Naphthalene was nitrated with a variety of nitrating agents. Comparison of data with Perrin's electrochemical nitration [Perrin, C. L. (1977) J. Am. Chem. Soc. 99, 5516-5518] shows that nitration of naphthalene gives an alpha-nitronaphthalene to beta-nitronaphthalene ratio that varies between 9 and 29 and is thus not constant. Perrin's data, therefore, are considered to be inconclusive evidence for the proposed one-electron transfer mechanism for the nitration of naphthalene and other reactive aromatics. Moodie and Schoefield [Hoggett, J. G., Moodie, R. B., Penton, J. R. & Schoefield, K. (1971) Nitration and Aromatic Reactivity (Cambridge Univ. Press, London)], as well as Perrin, independently concluded that, in the general scheme of nitration of reactive aromatics, there is the necessity to introduce into the classical Ingold mechanism an additional step involving a distinct intermediate preceding the formation of the Wheland intermediate (sigma complexes). This view coincides with our two-step mechanistic picture [Kuhn, S. J. & Olah, G. A. (1961) J. Am. Chem. Soc. 83, 4564-4571] of the nitronium salt nitration of aromatic hydrocarbons (including benzene and toluene), in which low substrate selectivity but high positional selectivity was found, indicating the independence of substrate from positional selectivity. PMID:16593026

  6. Quantification of nitrotyrosine in nitrated proteins

    PubMed Central

    Zhang, Yingyi; Pöschl, Ulrich

    2010-01-01

    For kinetic studies of protein nitration reactions, we have developed a method for the quantification of nitrotyrosine residues in protein molecules by liquid chromatography coupled to a diode array detector of ultraviolet-visible absorption. Nitrated bovine serum albumin (BSA) and nitrated ovalbumin (OVA) were synthesized and used as standards for the determination of the protein nitration degree (ND), which is defined as the average number of nitrotyrosine residues divided by the total number of tyrosine residues in a protein molecule. The obtained calibration curves of the ratio of chromatographic peak areas of absorbance at 357 and at 280 nm vs. nitration degree are nearly the same for BSA and OVA (relative deviations <5%). They are near-linear at low ND (< 0.1) and can be described by a second-order polynomial fit up to \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {\\hbox{ND}} = 0.5\\left( {{R^2} > 0.99} \\right) $$\\end{document}. A change of chromatographic column led to changes in absolute peak areas but not in the peak area ratios and related calibration functions, which confirms the robustness of the analytical method. First results of laboratory experiments confirm that the method is applicable for the investigation of the reaction kinetics of protein nitration. The main advantage over alternative methods is that nitration degrees can be efficiently determined without hydrolysis or digestion of the investigated protein molecules. PMID:20300739

  7. Microbial Reduction of Chromate in the Presence of Nitrate by Three Nitrate Respiring Organisms

    PubMed Central

    Chovanec, Peter; Sparacino-Watkins, Courtney; Zhang, Ning; Basu, Partha; Stolz, John F.

    2012-01-01

    A major challenge for the bioremediation of toxic metals is the co-occurrence of nitrate, as it can inhibit metal transformation. Geobacter metallireducens, Desulfovibrio desulfuricans, and Sulfurospirillum barnesii are three soil bacteria that can reduce chromate [Cr(VI)] and nitrate, and may be beneficial for developing bioremediation strategies. All three organisms respire through dissimilatory nitrate reduction to ammonia (DNRA), employing different nitrate reductases but similar nitrite reductase (Nrf). G. metallireducens reduces nitrate to nitrite via the membrane bound nitrate reductase (Nar), while S. barnesii and D. desulfuricans strain 27774 have slightly different forms of periplasmic nitrate reductase (Nap). We investigated the effect of DNRA growth in the presence of Cr(VI) in these three organisms and the ability of each to reduce Cr(VI) to Cr(III), and found that each organisms responded differently. Growth of G. metallireducens on nitrate was completely inhibited by Cr(VI). Cultures of D. desulfuricans on nitrate media was initially delayed (48?h) in the presence of Cr(VI), but ultimately reached comparable cell yields to the non-treated control. This prolonged lag phase accompanied the transformation of Cr(VI) to Cr(III). Viable G. metallireducens cells could reduce Cr(VI), whereas Cr(VI) reduction by D. desulfuricans during growth, was mediated by a filterable and heat stable extracellular metabolite. S. barnesii growth on nitrate was not affected by Cr(VI), and Cr(VI) was reduced to Cr(III). However, Cr(VI) reduction activity in S. barnesii, was detected in both the cell free spent medium and cells, indicating both extracellular and cell associated mechanisms. Taken together, these results have demonstrated that Cr(VI) affects DNRA in the three organisms differently, and that each have a unique mechanism for Cr(VI) reduction. PMID:23251135

  8. Synthesis of zirconium carbide from zircon concentrates in a thermal plasma reactor

    SciTech Connect

    Vidal, E.E.; Taylor, P.R.; Manrique, M.

    1996-10-01

    Ultrafine zirconium carbide powder has been synthesized using zircon concentrate and methane in a thermal plasma reactor. The effect of several experimental variables, such as power used and zircon particle size, on the conversion has been studied. A thermodynamic analysis of the possible reactions and stable compounds was performed. A mathematical model that describes the in-flight decomposition of zircon particles was developed based on a description of the temperature and velocity profiles calculated in the reactor. It was shown that the formation of zirconium carbide from zircon and methane is thermodynamically possible. Complete vaporization of zircon in the reactor is predicted when the particle size is below 45 {micro}m and the effective power entering the reactor is 15 kW. The powders were collected and characterized by XRD, SEM, TEM and chemical analysis using ICP. Results of the product analysis indicated the presence of zirconium carbide, zirconium oxide, silicon carbide and silicon oxide.

  9. Separation of Zirconium from Uranium in U-Zr Alloys Using a Chlorination Process 

    E-print Network

    Parkison, Adam J

    2013-06-04

    -scale chlorination and volatilization experiments were conducted on uranium, zirconium, and a U-50 wt% Zr alloy in order to gather the data needed to develop processing methods and equipment. It is also proposed that the demonstrated chlorination process may...

  10. JOURNAL OF MATERIALS SCIENCE 36 (2001) 77 86 Synthesis of yttria-doped strontium-zirconium

    E-print Network

    Iglesia, Enrique

    2001-01-01

    JOURNAL OF MATERIALS SCIENCE 36 (2001) 77­ 86 Synthesis of yttria-doped strontium-zirconium oxide densification, than co-precipitated powders. C 2001 Kluwer Academic Publishers 1. Introduction Strontium

  11. Low Temperature Chemical Vapor Deposition of Zirconium Nitride in a Fluidized Bed 

    E-print Network

    Arrieta, Marie

    2012-10-19

    The objective of this research was to design, assemble, and demonstrate the initial performance of a fluidized bed chemical vapor deposition (FB-CVD) system capable of producing thin, uniform zirconium nitride (ZrN) coatings (1 to 10 micrometers...

  12. 21 CFR 700.16 - Use of aerosol cosmetic products containing zirconium.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 2012-04-01 false Use of aerosol cosmetic products containing zirconium. 700.16...HEALTH AND HUMAN SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.16 Use of aerosol...

  13. 21 CFR 700.16 - Use of aerosol cosmetic products containing zirconium.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 2014-04-01 false Use of aerosol cosmetic products containing zirconium. 700.16...HEALTH AND HUMAN SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.16 Use of aerosol...

  14. 21 CFR 700.16 - Use of aerosol cosmetic products containing zirconium.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 2010-04-01 false Use of aerosol cosmetic products containing zirconium. 700.16...HEALTH AND HUMAN SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.16 Use of aerosol...

  15. 21 CFR 700.16 - Use of aerosol cosmetic products containing zirconium.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 2010-04-01 true Use of aerosol cosmetic products containing zirconium. 700.16...HEALTH AND HUMAN SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.16 Use of aerosol...

  16. 21 CFR 700.16 - Use of aerosol cosmetic products containing zirconium.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 2013-04-01 false Use of aerosol cosmetic products containing zirconium. 700.16...HEALTH AND HUMAN SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.16 Use of aerosol...

  17. Exclusion of Nitrate from Frozen Aqueous Solutions

    NASA Astrophysics Data System (ADS)

    Marrocco, H. A.; Michelsen, R. R.

    2013-12-01

    Reactions occurring at the surface of ice, sea ice, and snow in Earth's cryosphere have an impact on the composition of the overlying atmosphere. In order to elucidate reaction mechanisms and model their contributions to atmospheric processes, the morphology of frozen aqueous surfaces and amounts of reactants contained therein must be determined. To this end, the exclusion of nitrate ions to the surface of frozen aqueous solutions has been studied by attenuated total reflection infrared spectroscopy (ATR-IR). In this technique the near-surface region of the frozen films are interrogated to a depth of a few hundred nanometers from the film-crystal interface. Aqueous solutions (0.001 to 0.01 M) of sodium nitrate (NaNO3), magnesium nitrate (Mg(NO3)2), and nitric acid (HNO3) were quickly frozen on the germanium ATR crystal and observed at a constant temperature of about -18°C. In addition to ice and the solutes, liquid water in varying amounts was observed in the spectra. The amount of nitrate in the surface liquid is three to four orders of magnitude higher than in the unfrozen solution. While all the nitrate salts exhibit exclusion to the unfrozen surface, the dynamics are different for different counter-ions. Results are compared to freezing point depression data and the predictions of equilibrium thermodynamics.

  18. Measurement of plasma parameters in zirconium plasma using langmuir probe

    NASA Astrophysics Data System (ADS)

    Jana, B.; Majumder, A.; Baruah, S.; Sahu, G. K.; Thakur, K. B.; Mago, V. K.; Das, A. K.

    2012-06-01

    Zirconium (Zr) plasma is produced by electron-impact ionization during Zr vapor evaporation in an electron beam evaporator. The plasma is embedded in the vapor. It expands along with the vapor in a transverse magnetic field. Parameters like ion density, electron temperature, space potential, floating potential of the plasma were measured by a disc type Langmuir probe. Since Zr metal has high melting point (˜ 2128 K), the evaporator is filled with condensable vapor and remains at high temperature (˜ 700 K). The probe was designed and fabricated in a manner that the insulator was protected from the direct deposition of Zr vapor. The measurement shows that the e-beam generated plasma is weakly ionized (degree of ionization ˜ 0.1 %) and it has low electron temperature (˜ 0.1 eV). It is also observed that the plasma ions have a flow velocity in vertical direction similar to the neutral atoms.

  19. Titanium-Zirconium-Nickel Alloy Inside Marshall's Electrostatic Levitator (ESL)

    NASA Technical Reports Server (NTRS)

    2003-01-01

    This Photo, which appeared on the July cover of `Physics Today', is of the Electrostatic Levitator (ESL) at NASA's Marshall Space Flight Center (MSFC). The ESL uses static electricity to suspend an object (about 3-4 mm in diameter) inside a vacuum chamber allowing scientists to record a wide range of physical properties without the sample contracting the container or any instruments, conditions that would alter the readings. Once inside the chamber, a laser heats the sample until it melts. The laser is then turned off and the sample cools, changing from a liquid drop to a solid sphere. In this particular shot, the ESL contains a solid metal sample of titanium-zirconium-nickel alloy. Since 1977, the ESL has been used at MSFC to study the characteristics of new metals, ceramics, and glass compounds. Materials created as a result of these tests include new optical materials, special metallic glasses, and spacecraft components.

  20. Titanium-Zirconium-Nickel Alloy Inside Marshall's Electrostatic Levitator (ESL)

    NASA Technical Reports Server (NTRS)

    2003-01-01

    This is a close-up of a sample of titanium-zirconium-nickel alloy inside the Electrostatic Levitator (ESL) vacuum chamber at NASA's Marshall Space Flight Center (MSFC). The ESL uses static electricity to suspend an object (about 3-4 mm in diameter) inside a vacuum chamber allowing scientists to record a wide range of physical properties without the sample contracting the container or any instruments, conditions that would alter the readings. Once inside the chamber, a laser heats the sample until it melts. The laser is then turned off and the sample cools, changing from a liquid drop to a solid sphere. Since 1977, the ESL has been used at MSFC to study the characteristics of new metals, ceramics, and glass compounds. Materials created as a result of these tests include new optical materials, special metallic glasses, and spacecraft components.

  1. Studies on adsorption of formaldehyde in zirconium phosphate-glyphosates

    NASA Astrophysics Data System (ADS)

    Zhang, Yuejuan; Yi, Jianjun; Xu, Qinghong

    2011-01-01

    In our previous work [22], a kind of layered compound of zirconium phosphate-glyphosate (ZrGP) was synthesized. Its large surface area (445 m 2/g) indicates this compound has possible application in adsorptions. In this paper, adsorption to formaldehyde in ZrGP and mechanisms of the adsorption were studied carefully. Balance time of adsorption (about 6 h) and largest adsorbed amount (7.8%) were found when adsorption temperature was at 40 °C and pH value of adsorption environment was about 3.0. H-bonds were found existing between molecules of formaldehyde and ZrGP, and formaldehyde molecules could exist in ZrGP stably.

  2. Corrosion of Zirconium Alloys Used for Nuclear Fuel Cladding

    NASA Astrophysics Data System (ADS)

    Motta, Arthur T.; Couet, Adrien; Comstock, Robert J.

    2015-07-01

    During operation, nuclear fuel rods are immersed in the primary water, causing waterside corrosion and consequent hydrogen ingress. In this review, the mechanisms of corrosion and hydrogen pickup and the role of alloy selection in minimizing both phenomena are considered on the basis of two principal characteristics: the pretransition kinetics and the loss of oxide protectiveness at transition. In zirconium alloys, very small changes in composition or microstructure can cause significant corrosion differences so that corrosion performance is strongly alloy dependent. The alloys show different, but reproducible, subparabolic pretransition kinetics and transition thicknesses. A mechanism for oxide growth and breakup based on a detailed study of the oxide structure can explain these results. Through the use of the recently developed coupled current charge compensation model of corrosion kinetics and hydrogen pickup, the subparabolic kinetics and the hydrogen fraction can be rationalized: Hydrogen pickup increases when electron transport decreases, requiring hydrogen ingress to close the reaction.

  3. Dislocation locking versus easy glide in titanium and zirconium.

    PubMed

    Clouet, Emmanuel; Caillard, Daniel; Chaari, Nermine; Onimus, Fabien; Rodney, David

    2015-09-01

    The ease of a metal to deform plastically in selected crystallographic planes depends on the core structure of its dislocations. As the latter is controlled by electronic interactions, metals with the same valence electron configuration usually exhibit a similar plastic behaviour. For this reason, titanium and zirconium, two transition metals of technological importance from the same column of the periodic table, have so far been assumed to deform in a similar fashion. However, we show here, using in situ transmission electron microscopy straining experiments, that plasticity proceeds very differently in these two metals, being intermittent in Ti and continuous in Zr. This observation is rationalized using first-principles calculations, which reveal that, in both metals, dislocations may adopt the same set of different cores that are either glissile or sessile. An inversion of stability of these cores between Zr and Ti is shown to be at the origin of the profoundly different plastic behaviours. PMID:26147845

  4. Dislocation locking versus easy glide in titanium and zirconium

    NASA Astrophysics Data System (ADS)

    Clouet, Emmanuel; Caillard, Daniel; Chaari, Nermine; Onimus, Fabien; Rodney, David

    2015-09-01

    The ease of a metal to deform plastically in selected crystallographic planes depends on the core structure of its dislocations. As the latter is controlled by electronic interactions, metals with the same valence electron configuration usually exhibit a similar plastic behaviour. For this reason, titanium and zirconium, two transition metals of technological importance from the same column of the periodic table, have so far been assumed to deform in a similar fashion. However, we show here, using in situ transmission electron microscopy straining experiments, that plasticity proceeds very differently in these two metals, being intermittent in Ti and continuous in Zr. This observation is rationalized using first-principles calculations, which reveal that, in both metals, dislocations may adopt the same set of different cores that are either glissile or sessile. An inversion of stability of these cores between Zr and Ti is shown to be at the origin of the profoundly different plastic behaviours.

  5. Effect of yttrium on nucleation and growth of zirconium hydrides

    NASA Astrophysics Data System (ADS)

    Li, Changji; Xiong, Liangyin; Wu, Erdong; Liu, Shi

    2015-02-01

    Addition of yttrium in zirconium causes precipitates of yttrium, which form two types of particles and are oxidized upon heat treatment. One type of particles with sub-micrometer scale sizes has a low population, whereas the other with nano scale sizes has a high population and cluster distribution. Owing to strong affinity of yttrium to hydrogen, the nanoparticles, mostly within the grains of the Zr-Y alloy, attract nucleation of hydrides at the clusters of the nanoparticles and cause preferential distribution of intragranular hydrides. In comparison with that of Zr, additional nanoparticles in the Zr-Y alloy impede further growth of hydride precipitates during hydriding. It is deduced that the impediment of growing hydride precipitates by the nanoparticles is developed during an auto-catalytic nucleation process, which leads to formation of thin and intragranular hydrides, favorable to mitigation of hydride embrittlement.

  6. Co-Rolled U10Mo/Zirconium-Barrier-Layer Monolithic Fuel Foil Fabrication Process

    SciTech Connect

    G. A. Moore; M. C. Marshall

    2010-01-01

    Integral to the current UMo fuel foil processing scheme being developed at Idaho National Laboratory (INL) is the incorporation of a zirconium barrier layer for the purpose of controlling UMo-Al interdiffusion at the fuel-meat/cladding interface. A hot “co-rolling” process is employed to establish a ~25-µm-thick zirconium barrier layer on each face of the ~0.3-mm-thick U10Mo fuel foil.

  7. Generalized Gruneisen parameters and low temperature limit of lattice thermal expansion of cadmium and zirconium

    NASA Astrophysics Data System (ADS)

    Sindhu, S.; Menon, C. S.

    2006-09-01

    The generalized Grüneisen parameters (?_j) and (?_j) for cadmium and zirconium were calculated from the second- and third-order elastic constants to determine the low temperature limit of the volume thermal expansion of these metals of hexagonal symmetry. The low temperature limit of cadmium and zirconium was calculated to be positive values indicating a positive volume expansion down to 0 K even though many Grüneisen gammas were found to be negative.

  8. Atomic Diffusion in the Uranium-50wt% Zirconium Nuclear Fuel System 

    E-print Network

    Eichel, Daniel

    2013-06-17

    -1 ATOMIC DIFFUSION IN THE URANIUM-50WT% ZIRCONIUM NUCLEAR FUEL SYSTEM A Thesis by DANIEL R. EICHEL Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER... design concept. Image courtesy Lightbridge Corporation. ............................................... 2 Figure 2: Phase diagram for the binary zirconium-uranium system, showing the existence of the ? phase below 600?C for alloy compositions...

  9. Techniques for Measurement of Nitrate Movement in Soils

    NASA Technical Reports Server (NTRS)

    Broadbent, F. E.

    1971-01-01

    Contamination of surface and ground waters with nitrate usually involves leaching through soil of nitrate produced by mineralization of soil organic matter, decomposition of animal wastes or plant residues, or derived from fertilizers. Nitrate concentrations in the soil solution may be measured by several chemical procedures or by the nitrate electrode. since nitrate is produced throughout the soil mass it is difficult to identify a source of nitrate contamination by conventional means. This problem can be solved by use of N-15-enriched or N-15-depleted materials as tracers. The latter is particularly attractive because of the negligible possibility of the tracer hazardous to health.

  10. The role of nitrate reductase in the regulation of the nitrate assimilation pathway in the yeast Hansenula polymorpha.

    PubMed

    Navarro, Francisco J; Perdomo, Germán; Tejera, Paula; Medina, Braulio; Machín, Félix; Guillén, Rosa Maria; Lancha, Ana; Siverio, José M

    2003-11-01

    The role of nitrate reductase (NR) in the regulation of the nitrate assimilation pathway was evaluated in the yeast Hansenula polymorpha. Posttranscriptional regulation of NR in response to reduced nitrogen sources and the effect of a heterologous NR on the transcriptional regulation of nitrate-assimilatory gene expression was examined. The strain bearing YNR1 (nitrate reductase gene) under the control of the methanol-induced MOX (methanol oxidase) promoter showed that NR is active in the presence of reduced nitrogen sources. In cells incubated with glutamine plus nitrate, rapamycin abolished nitrogen catabolite repression, NR activity being very similar to that in cells induced by nitrate alone. This reveals the involvement of the Tor-signalling pathway in the transcriptional regulation of H. polymorpha nitrate assimilation genes. To assess the role of NR in nitrate-assimilatory gene expression, different strains lacking YNR1, or both YNR1 and YNT1 (high-affinity nitrate transporter) genes, or expressing the tobacco NR under the YNR1 promoter, were used. Tobacco NR abolished the constitutive nitrate-assimilatory gene induction shown by an NR gene disruptant strain. Moreover, in strains lacking the high-affinity nitrate transporter and NR this deregulation disappeared. These facts discard the role of NR protein in the transcriptional induction of the nitrate-assimilatory genes and point out the involvement of the high-affinity nitrate transporter as a part of the nitrate-signalling pathway. PMID:14613879

  11. Nitrate postdeposition processes in Svalbard surface snow

    NASA Astrophysics Data System (ADS)

    Björkman, Mats P.; Vega, Carmen P.; Kühnel, Rafael; Spataro, Francesca; Ianniello, Antonietta; Esposito, Giulio; Kaiser, Jan; Marca, Alina; Hodson, Andy; Isaksson, Elisabeth; Roberts, Tjarda J.

    2014-11-01

    The snowpack acts as a sink for atmospheric reactive nitrogen, but several postdeposition pathways have been reported to alter the concentration and isotopic composition of snow nitrate with implications for atmospheric boundary layer chemistry, ice core records, and terrestrial ecology following snow melt. Careful daily sampling of surface snow during winter (11-15 February 2010) and springtime (9 April to 5 May 2010) near Ny-Ålesund, Svalbard reveals a complex pattern of processes within the snowpack. Dry deposition was found to dominate over postdeposition losses, with a net nitrate deposition rate of (0.6 ± 0.2) µmol m-2 d-1 to homogeneous surface snow. At Ny-Ålesund, such surface dry deposition can either solely result from long-range atmospheric transport of oxidized nitrogen or include the redeposition of photolytic/bacterial emission originating from deeper snow layers. Our data further confirm that polar basin air masses bring 15N-depleted nitrate to Svalbard, while high nitrate ?(18O) values only occur in connection with ozone-depleted air, and show that these signatures are reflected in the deposited nitrate. Such ozone-depleted air is attributed to active halogen chemistry in the air masses advected to the site. However, here the Ny-Ålesund surface snow was shown to have an active role in the halogen dynamics for this region, as indicated by declining bromide concentrations and increasing nitrate ?(18O), during high BrO (low-ozone) events. The data also indicate that the snowpack BrO-NOx cycling continued in postevent periods, when ambient ozone and BrO levels recovered.

  12. A Reservoir of Nitrate Beneath Desert Soils

    USGS Publications Warehouse

    Walvoord, M.A.; Phillips, F.M.; Stonestrom, D.A.; Evans, R.D.; Hartsough, P.C.; Newman, B.D.; Striegl, R.G.

    2003-01-01

    A large reservoir of bioavailable nitrogen (upto ???104 kilograms of nitrogen per hectare, as nitrate) has been previously overlooked in studies of global nitrogen distribution. The reservoir has been accumulating in subsoil zones of and regions throughout the Holocene. Consideration of the subsoil reservoir raises estimates of vadose-zone nitrogen inventories by 14 to 71% for warm deserts and arid shrublands worldwide and by 3 to 16% globally. Subsoil nitrate accumulation indicates long-term leaching from desert soils, impelling further evaluation of nutrient dynamics in xeric ecosystems. Evidence that subsoil accumulations are readily mobilized raises concern about groundwater contamination after land-use or climate change.

  13. The Acid Catalyzed Nitration of Methanol: Formation of Methyl Nitrate via Aerosol Chemistry

    NASA Technical Reports Server (NTRS)

    Riffel, Brent G.; Michelsen, Rebecca R.; Iraci, Laura T.

    2004-01-01

    The liquid phase acid catalyzed reaction of methanol with nitric acid to yield methyl nitrate under atmospheric conditions has been investigated using gas phase infrared spectroscopy. This nitration reaction is expected to occur in acidic aerosol particles found in the upper troposphere/lower stratosphere as highly soluble methanol and nitric acid diffuse into these aerosols. Gaseous methyl nitrate is released upon formation, suggesting that some fraction of NO(x) may he liberated from nitric acid (methyl nitrate is later photolyzed to NO(x)) before it is removed from the atmosphere by wet deposition. Thus, this reaction may have important implications for the NO(x) budget. Reactions have been initiated in 45-62 wt% H2SO4 solutions at 10.0 C. Methyl nitrate production rates increased exponentially with acidity within the acidity regime studied. Preliminary calculations suggest that the nitronium ion (NO2(+) is the active nitrating agent under these conditions. The reaction order in methanol appears to depend on the water/methanol ratio and varies from first to zeroth order under conditions investigated. The nitration is first order in nitronium at all acidities investigated. A second order rate constant, kappa(sub 2), has been calculated to be 1 x 10(exp 8)/ M s when the reaction is first order in methanol. Calculations suggest the nitration is first order in methanol under tropospheric conditions. The infinitesimal percentage of nitric acid in the nitronium ion form in this acidity regime probably makes this reaction insignificant for the upper troposphere; however, this nitration may become significant in the mid stratosphere where colder temperatures increase nitric acid solubility and higher sulfuric acid content shifts nitric acid speciation toward the nitronium ion.

  14. Modeling of sink-induced irradiation growth of single-crystal and polycrystal zirconiums in nuclear reactors

    NASA Astrophysics Data System (ADS)

    Choi, Sang Il; Lee, Gyeong-Geun; Kwon, Junhyun; Kim, Ji Hyun

    2016-01-01

    The objective of this study is irradiation growth modeling of polycrystal zirconium using the advanced mean-field rate theory (MFRT) and growth equation. Since the 1960s, irradiation growth of zirconium has been among the most important phenomena in nuclear reactors. However, there is no general irradiation growth model that can explain changes in both the microstructure morphology and growth strain in polycrystal zirconium owing to lack of knowledge of the relevant atomistic information and MFRT. Although two groups have developed a single-crystal zirconium irradiation growth model, a general polycrystal zirconium model has not been developed. In this study, therefore, the defect flux was calculated using the MFRT, and the dislocation loop density was calculated from the defect flux. Moreover, the bias factor for each sink (dislocation lines, loops, and grain boundaries) was adopted in the MFRT. In addition, dislocation line and grain boundary effects were examined in polycrystal zirconiums. Finally, irradiation growth equation was established and growth strain was calculated using the average strain factor and anisotropy factor considering grain-interaction. For single-crystal zirconium and cold-worked polycrystal zirconium, irradiation growth strain results show good agreement with the experimental results. For annealed polycrystal zirconium, the results deviate from the experimental results.

  15. CURRENT METHODS TO MEASURE ATMOSPHERIC NITRIC ACID AND NITRATE ARTIFACTS

    EPA Science Inventory

    Presentations given at a workshop on 'Measurement of Atmospheric Nitrates' (Southern Pines, N.C. October 3-4, 1978) are documented. The authors consider various analytical methods to measure ambient concentrations of nitric acid and artifact nitrate formation.

  16. 46 CFR 148.220 - Ammonium nitrate-phosphate fertilizers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...false Ammonium nitrate-phosphate fertilizers. 148.220 Section 148.220 ...220 Ammonium nitrate-phosphate fertilizers. (a) This section applies to...phosphate or nitrogen/potash type fertilizers, or complete fertilizers of...

  17. 46 CFR 148.220 - Ammonium nitrate-phosphate fertilizers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...false Ammonium nitrate-phosphate fertilizers. 148.220 Section 148.220 ...220 Ammonium nitrate-phosphate fertilizers. (a) This section applies to...phosphate or nitrogen/potash type fertilizers, or complete fertilizers of...

  18. 46 CFR 148.220 - Ammonium nitrate-phosphate fertilizers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...false Ammonium nitrate-phosphate fertilizers. 148.220 Section 148.220 ...220 Ammonium nitrate-phosphate fertilizers. (a) This section applies to...phosphate or nitrogen/potash type fertilizers, or complete fertilizers of...

  19. 46 CFR 148.220 - Ammonium nitrate-phosphate fertilizers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...false Ammonium nitrate-phosphate fertilizers. 148.220 Section 148.220 ...220 Ammonium nitrate-phosphate fertilizers. (a) This section applies to...phosphate or nitrogen/potash type fertilizers, or complete fertilizers of...

  20. ORNL/TM-2008/048 Uranyl Nitrate Flow Loop

    E-print Network

    Pennycook, Steve

    ORNL/TM-2008/048 Uranyl Nitrate Flow Loop October 2008 Jennifer L. Ladd-Lively #12;DOCUMENT Government or any agency thereof. #12;ORNL/TM-2008/048 Nuclear Science and Technology Division URANYL NITRATE

  1. Perchlorate and nitrate in situ bioremediation of ground water

    SciTech Connect

    Strietelmeier, E. A.; Nuttall, H. Eric; Hatzinger, Paul; Goltz, Mark

    2002-01-01

    Nitrate and perchlorate are growing worldwide problems as mobile anionic groundwater contaminants. Biological rduction of nitrate and perchlorate in groundwater is under development as a technology to address these problems.

  2. Concept Feasibility Report for Electroplating Zirconium onto Uranium Foil - Year 2

    SciTech Connect

    Coffey, Greg W.; Meinhardt, Kerry D.; Joshi, Vineet V.; Pederson, Larry R.; Lavender, Curt A.; Burkes, Douglas

    2015-03-01

    The Fuel Fabrication Capability within the U.S. High Performance Research Reactor Conversion Program is funded through the National Nuclear Security Administration (NNSA) NA-26 (Office of Material Management and Minimization). An investigation was commissioned to determine the feasibility of using electroplating techniques to apply a coating of zirconium onto depleted uranium/molybdenum alloy (U-10Mo). Electroplating would provide an alternative method to the existing process of hot roll-bonding zirconium foil onto the U-10Mo fuel foil during the fabrication of fuel elements for high-performance research reactors. The objective of this research was to develop a reproducible and scalable plating process that will produce a uniform, 25 ?m thick zirconium metal coating on U-10Mo foil. In previous work, Pacific Northwest National Laboratory (PNNL) established a molten salt electroplating apparatus and protocol to plate zirconium metal onto molybdenum foil (Coffey 2015). During this second year of the research, PNNL furthered this work by moving to the U-10Mo alloy system (90 percent uranium:10 percent molybdenum). The original plating apparatus was disassembled and re-assembled in a laboratory capable of handling low-level radioactive materials. Initially, the work followed the previous year’s approach, and the salt bath composition was targeted at the eutectic composition (LiF:NaF:ZrF4 = 26:37:37 mol%). Early results indicated that the formation of uranium fluoride compounds would be problematic. Other salt bath compositions were investigated in order to eliminate the uranium fluoride production (LiF:NaF = 61:39 mol% and LiF:NaF:KF = 46.5:11.5:42 mol% ). Zirconium metal was used as the crucible for the molten salt. Three plating methods were used—isopotential, galvano static, and pulsed plating. The molten salt method for zirconium metal application provided high-quality plating on molybdenum in PNNL’s previous work. A key advantage of this approach is that plating can be performed under conditions that would greatly reduce the quantity of intermetallics that form at the interface between the zirconium and U-10Mo; unlike roll bonding, the molten salt plating approach would allow for complete coverage of the U-10Mo foil with zirconium. When utilizing the experimental parameters developed for zirconium plating onto molybdenum, a uranium fluoride reaction product was formed at the Zr/U-10Mo interface. By controlling the initial plating potential, the uranium fluoride could be prevented; however, the targeted zirconium thickness (25 ±12.5 ?m) could not be achieved while maintaining 100% coverage.

  3. 77 FR 65532 - Solid Fertilizer Grade Ammonium Nitrate From the Russian Federation: Notice of Rescission of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-29

    ...Administration [A-821-811] Solid Fertilizer Grade Ammonium Nitrate From the Russian...the antidumping duty order on solid fertilizer grade ammonium nitrate (ammonium nitrate...Antidumping Duty Administrative Review: Solid Fertilizer Grade Ammonium Nitrate (Ammonium...

  4. A toxicological study of gadolinium nitrate

    SciTech Connect

    London, J.E.

    1988-05-01

    The sensitization study in the guinea pig did not show gadolinium nitrate to have potential sensitizing properties. Skin application studies in the rabbit demonstrated that it was cutaneously a severe irritant. This material was considered an irritant in the rabbit eye application studies. 3 refs., 1 tab.

  5. Nitrates, Nitrites, and Health. Bulletin 750.

    ERIC Educational Resources Information Center

    Deeb, Barbara S.; Sloan, Kenneth W.

    This review is intended to assess available literature in order to define the range of nitrate/nitrite effects on animals. Though the literature deals primarily with livestock and experimental animals, much of the contemporary research is concerned with human nitrite intoxication. Thus, the effects on man are discussed where appropriate. Some of…

  6. 76 FR 70366 - Ammonium Nitrate Security Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-14

    ... Department previously announced a series of public meetings on the same topic on October 2, 2011 (see 76 FR... public comment on August 3, 2011. See 73 FR 64280 (advance notice of proposed rulemaking); 76 FR 46908... the Department's Ammonium Nitrate Security Program Web site, at...

  7. Nitrate Salt Surrogate Blending Scoping Test Plan

    SciTech Connect

    Anast, Kurt Roy

    2015-11-13

    Test blending equipment identified in the “Engineering Options Assessment Report: Nitrate Salt Waste Stream Processing”. Determine if the equipment will provide adequate mixing of zeolite and surrogate salt/Swheat stream; optimize equipment type and operational sequencing; impact of baffles and inserts on mixing performance; and means of validating mixing performance

  8. 76 FR 47238 - Ammonium Nitrate From Russia

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-04

    ...)). Background The Commission instituted this review on March 1, 2011 (76 FR 11273) and determined on June 6, 2011 that it would conduct an expedited review (76 FR 34749, June 14, 2011). The Commission transmitted... Ammonium Nitrate From Russia Determination On the basis of the record \\1\\ developed in the subject...

  9. 76 FR 11273 - Ammonium Nitrate From Russia

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-01

    ... nitrate from Russia (71 FR 17080). The Commission is now conducting a second review to determine whether... recently amended at 74 FR 2847 (January 16, 2009). \\1\\ No response to this request for information is... (65 FR 37759, June 16, 2000). Following five-year reviews by Commerce and the Commission,...

  10. 4-Meth­oxy­anilinium nitrate

    PubMed Central

    Rahmouni, Hajer; Smirani Sta, Wajda; Al-Deyab, S. Salem; Rzaigui, Mohamed

    2011-01-01

    The title compound, C7H10NO+·NO3 ?, crystallized with two p-ansidinium cations and two nitrate anions in the asymmetric unit. As well as Columbic and van der Waals forces, moleucles inter­act via multiple bifurcated N—H?O hydrogen bonds that help consolidate the crystal packing, resulting in a three-dimensional network. PMID:22065633

  11. PEROXYCHLOROFORMYL NITRATE: SYNTHESIS AND THERMAL STABILITY

    EPA Science Inventory

    Peroxychloroformyl nitrate, ClC(O)OONO2, has been identified as the principal product of the ultraviolet irradiation of Cl2, NO2, and CO mixtures in air. Fourier Transform IR spectroscopic detection methods have been used to identify the newly detected compound and to establish i...

  12. Negative ion spectrometry for detecting nitrated explosives

    NASA Technical Reports Server (NTRS)

    Boettger, H. G.; Yinon, J.

    1975-01-01

    Ionization procedure is modified to produce mainly negative ions by electron capture. Peaks of negative ions are monitored conventionally. Nitrated organic materials could be identified directly from sample sniff inlet stream by suitably modified mass spectrometer because of unique electronegativity which nitro group imparts to organic material.

  13. 21 CFR 172.160 - Potassium nitrate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium nitrate. 172.160 Section 172.160 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.160 Potassium...

  14. Denitration of High Nitrate Salts Using Reductants

    SciTech Connect

    HD Smith; EO Jones; AJ Schmidt; AH Zacher; MD Brown; MR Elmore; SR Gano

    1999-05-03

    This report describes work conducted by Pacific Northwest National Laboratory (PNNL), in conjunction with Idaho National Engineering and Environmental Laboratory (INEEL), to remove nitrates in simulated low-activity waste (LAW). The major objective of this work was to provide data for identifying and demonstrating a technically viable and cost-effective approach to condition LAW for immobilization (grout).

  15. 76 FR 46907 - Ammonium Nitrate Security Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-03

    ...section 31.235 of the proposed rule to make each AN Registered User Number...Ammonium Nitrate Security Program, and to make the records available for inspection by...proposes that each AN Facility be required to make records available within the...

  16. SOIL DEVELOPMENT AND NITRATES IN MINESOIL

    EPA Science Inventory

    Samples of minesoils from 16- and 40-year-old mine spoil piles were analyzed in the laboratory for various chemical and physical properties to ascertain to what extent the material have been influenced by pedogenic processes during their relatively brief time of exposure. Nitrate...

  17. Enzyme catalytic nitration of aromatic compounds.

    PubMed

    Kong, Mingming; Wang, Kun; Dong, Runan; Gao, Haijun

    2015-06-01

    Nitroaromatic compounds are important intermediates in organic synthesis. The classic method used to synthesize them is chemical nitration, which involves the use of nitric acid diluted in water or acetic acid, both harmful to the environment. With the development of green chemistry, environmental friendly enzyme catalysis is increasingly employed in chemical processes. In this work, we adopted a non-aqueous horseradish peroxidase (HRP)/NaNO2/H2O2 reaction system to study the structural characteristics of aromatic compounds potentially nitrated by enzyme catalysis, as well as the relationship between the charges on carbon atoms in benzene ring and the nitro product distribution. Investigation of various reaction parameters showed that mild reaction conditions (ambient temperature and neutral pH), plus appropriate use of H2O2 and NaNO2 could prevent inactivation of HRP and polymerization of the substrates. Compared to aqueous-organic co-solvent reaction media, the aqueous-organic two-liquid phase system had great advantages in increasing the dissolved concentration of substrate and alleviating substrate inhibition. Analysis of the aromatic compounds' structural characteristics indicated that substrates containing substituents of NH2 or OH were readily catalyzed. Furthermore, analysis of the relationship between natural bond orbital (NBO) charges on carbon atoms in benzene ring, as calculated by the density functional method, and the nitro product distribution characteristics, demonstrated that the favored nitration sites were the ortho and para positions of substituents in benzene ring, similar to the selectivity of chemical nitration. PMID:26002502

  18. 46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...percent of combustible material; and (4) Nitrogen phosphate or nitrogen/potash type fertilizers or complete nitrogen/phosphate/potash type fertilizers containing more than 70 percent but less than 90 percent of ammonium nitrate and a...

  19. 46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...percent of combustible material; and (4) Nitrogen phosphate or nitrogen/potash type fertilizers or complete nitrogen/phosphate/potash type fertilizers containing more than 70 percent but less than 90 percent of ammonium nitrate and a...

  20. 46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...percent of combustible material; and (4) Nitrogen phosphate or nitrogen/potash type fertilizers or complete nitrogen/phosphate/potash type fertilizers containing more than 70 percent but less than 90 percent of ammonium nitrate and a...

  1. 46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...percent of combustible material; and (4) Nitrogen phosphate or nitrogen/potash type fertilizers or complete nitrogen/phosphate/potash type fertilizers containing more than 70 percent but less than 90 percent of ammonium nitrate and a...

  2. Evidence for a plasma-membrane-bound nitrate reductase involved in nitrate uptake of Chlorella sorokiniana

    NASA Technical Reports Server (NTRS)

    Tischner, R.; Ward, M. R.; Huffaker, R. C.

    1989-01-01

    Anti-nitrate-reductase (NR) immunoglobulin-G (IgG) fragments inhibited nitrate uptake into Chlorella cells but had no affect on nitrate uptake. Intact anti-NR serum and preimmune IgG fragments had no affect on nitrate uptake. Membrane-associated NR was detected in plasma-membrane (PM) fractions isolated by aqueous two-phase partitioning. The PM-associated NR was not removed by sonicating PM vesicles in 500 mM NaCl and 1 mM ethylenediaminetetraacetic acid and represented up to 0.8% of the total Chlorella NR activity. The PM NR was solubilized by Triton X-100 and inactivated by Chlorella NR antiserum. Plasma-membrane NR was present in ammonium-grown Chlorella cells that completely lacked soluble NR activity. The subunit sizes of the PM and soluble NRs were 60 and 95 kDa, respectively, as determined by sodium-dodecyl-sulfate electrophoresis and western blotting.

  3. 21 CFR 176.320 - Sodium nitrate-urea complex.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium nitrate-urea complex. 176.320 Section 176... Paperboard § 176.320 Sodium nitrate-urea complex. Sodium nitrate-urea complex may be safely used as a..., packaging, transporting, or holding food, subject to the provisions of this section. (a) Sodium...

  4. 21 CFR 176.320 - Sodium nitrate-urea complex.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium nitrate-urea complex. 176.320 Section 176... Substances for Use Only as Components of Paper and Paperboard § 176.320 Sodium nitrate-urea complex. Sodium... the provisions of this section. (a) Sodium nitrate-urea complex is a clathrate of approximately...

  5. 21 CFR 176.320 - Sodium nitrate-urea complex.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrate-urea complex. 176.320 Section 176... Substances for Use Only as Components of Paper and Paperboard § 176.320 Sodium nitrate-urea complex. Sodium... the provisions of this section. (a) Sodium nitrate-urea complex is a clathrate of approximately...

  6. THE CONTROL OF NITRATE AS A WATER POLLUTANT

    EPA Science Inventory

    This study was based on the premise that the most logical approach to reducing nitrate leaching in soils was to limit the amount of nitrate in the soil solution at any one time. Methods of limiting the concentration of nitrate in the soil solution while maintaining an adequate su...

  7. 40 CFR 721.5769 - Mixture of nitrated alkylated phenols.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Mixture of nitrated alkylated phenols... Substances § 721.5769 Mixture of nitrated alkylated phenols. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as a mixture of nitrated alkylated...

  8. 40 CFR 721.5769 - Mixture of nitrated alkylated phenols.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Mixture of nitrated alkylated phenols... Substances § 721.5769 Mixture of nitrated alkylated phenols. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as a mixture of nitrated alkylated...

  9. 40 CFR 721.5769 - Mixture of nitrated alkylated phenols.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Mixture of nitrated alkylated phenols... Substances § 721.5769 Mixture of nitrated alkylated phenols. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as a mixture of nitrated alkylated...

  10. 40 CFR 721.5769 - Mixture of nitrated alkylated phenols.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Mixture of nitrated alkylated phenols... Substances § 721.5769 Mixture of nitrated alkylated phenols. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as a mixture of nitrated alkylated...

  11. 40 CFR 721.5769 - Mixture of nitrated alkylated phenols.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Mixture of nitrated alkylated phenols... Substances § 721.5769 Mixture of nitrated alkylated phenols. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as a mixture of nitrated alkylated...

  12. Sap Analysis for Diagnosis of Nitrate Accumulation in Cereal Forages

    E-print Network

    Lawrence, Rick L.

    Sap Analysis for Diagnosis of Nitrate Accumulation in Cereal Forages Mal Westcott1 , Dennis Cash2 be expected after harvest. Our objective was to determine if nitrate concentrations in sap expressed from in the dry hay. We also sought to determine if this sap nitrate analysis could be reliably performed

  13. SULFATE AND NITRATE COATINGS ON MINERAL DUSTS: CRYSTALLINE OR AQUEOUS?

    E-print Network

    SULFATE AND NITRATE COATINGS ON MINERAL DUSTS: CRYSTALLINE OR AQUEOUS? Scot T. Martin, Hui 02138, USA Keywords: Phase transition; Atmospheric Aerosols; Ammonium sulfate; Ammonium nitrate Observational evidence shows that mineral dusts in Asian outflows become coated by sulfates and nitrates. Layer

  14. EUROPEAN LARGE LAKES III Identification of factors constraining nitrate assimilation

    E-print Network

    Berges, John A.

    EUROPEAN LARGE LAKES III Identification of factors constraining nitrate assimilation in Lake Science+Business Media Dordrecht 2013 Abstract Despite a well-documented rise in nitrate concentration to assess the influence of light and nutrients (P, Fe) on nitrate assimilation by a Lake Superior

  15. 9 CFR 319.2 - Products and nitrates and nitrites.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 false Products and nitrates and nitrites. 319.2 Section 319... General § 319.2 Products and nitrates and nitrites. Any product, such...is a standard in this part and to which nitrate or nitrite is permitted or required...

  16. Turbulent nitrate fluxes in the Amundsen Gulf during icecovered conditions

    E-print Network

    Turbulent nitrate fluxes in the Amundsen Gulf during icecovered conditions D. Bourgault,1 C. Hamel; revised 21 June 2011; accepted 23 June 2011; published 2 August 2011. [1] Turbulence and nitrate mean vertical profiles of eddy diffusivity K and diffusive nitrate fluxes F. The mean diffusivity (with

  17. Introduction Current methods to determine nitrate (NO3

    E-print Network

    Sigman, Daniel M.

    205 Introduction Current methods to determine nitrate (NO3 ­ ) nitrogen (N) and oxygen (O) isotope of nitrate versus that of nitrite in a given sample. In the case of the ammonia distillation (Cline and Kaplan 1975) and ammonia diffusion (Sigman et al. 1997) methods for nitrate N isotope analysis, both

  18. 9 CFR 319.2 - Products and nitrates and nitrites.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 false Products and nitrates and nitrites. 319.2 Section 319... General § 319.2 Products and nitrates and nitrites. Any product, such...is a standard in this part and to which nitrate or nitrite is permitted or required...

  19. 9 CFR 319.2 - Products and nitrates and nitrites.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 false Products and nitrates and nitrites. 319.2 Section 319... General § 319.2 Products and nitrates and nitrites. Any product, such...is a standard in this part and to which nitrate or nitrite is permitted or required...

  20. 9 CFR 319.2 - Products and nitrates and nitrites.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 false Products and nitrates and nitrites. 319.2 Section 319... General § 319.2 Products and nitrates and nitrites. Any product, such...is a standard in this part and to which nitrate or nitrite is permitted or required...

  1. ORIGINAL ARTICLE Impact of elevated nitrate on sulfate-reducing

    E-print Network

    Hazen, Terry

    ORIGINAL ARTICLE Impact of elevated nitrate on sulfate-reducing bacteria: a comparative Study, the occurrence of elevated nitrate in contaminated environments has been shown to inhibit sulfate reduction activity. Although the inhibition has been suggested to result from the competition with nitrate

  2. Nitrate variability along the Oregon coast: Estuarineecoastal exchange

    E-print Network

    Nitrate variability along the Oregon coast: Estuarineecoastal exchange A.C. Sigleo a,*, C.W. Mordy. To quantify the coastal ocean nitrogen input to Yaquina Bay, Oregon, nitrate concentrations were measured. Nitrate concentrations associated with coastal upwelling were generally high (up to 34 mmol lÿ1

  3. Coupling the 15 O of nitrate as a constraint on

    E-print Network

    Sigman, Daniel M.

    Coupling the 15 N/14 N and 18 O/16 O of nitrate as a constraint on benthic nitrogen cycling Moritz February 2004 Abstract We report 15 N/14 N and 18 O/16 O ratios of nitrate in benthic chamber incubationsÀ 2 dÀ 1 . Between 46% and 100% of the total denitrification can be explained by nitrate or nitrite

  4. 9 CFR 319.2 - Products and nitrates and nitrites.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 false Products and nitrates and nitrites. 319.2 Section 319... General § 319.2 Products and nitrates and nitrites. Any product, such...is a standard in this part and to which nitrate or nitrite is permitted or required...

  5. Estimating the range of impacts arising from nitrate leaching reduction

    E-print Network

    Bateman, Ian J.

    Estimating the range of impacts arising from nitrate leaching reduction policies using farm ECM 07-02 #12;Estimating the range of impacts arising from nitrate leaching reduction policies using of the Water Framework Directive (European Commission, 2000). Like the Nitrates Directive (European Commission

  6. NITRATE DESTRUCTION LITERATURE SURVEY AND EVALUATION CRITERIA

    SciTech Connect

    Steimke, J.

    2011-02-01

    This report satisfies the initial phase of Task WP-2.3.4 Alternative Sodium Recovery Technology, Subtask 1; Develop Near-Tank Nitrate/Nitrite Destruction Technology. Some of the more common anions in carbon steel waste tanks at SRS and Hanford Site are nitrate which is corrosive, and nitrite and hydroxide which are corrosion inhibitors. At present it is necessary to periodically add large quantities of 50 wt% caustic to waste tanks. There are three primary reasons for this addition. First, when the contents of salt tanks are dissolved, sodium hydroxide preferentially dissolves and is removed. During the dissolution process the concentration of free hydroxide in the tank liquid can decrease from 9 M to less than 0.2 M. As a result, roughly half way through the dissolution process large quantities of sodium hydroxide must be added to the tank to comply with requirements for corrosion control. Second, hydroxide is continuously consumed by reaction with carbon dioxide which occurs naturally in purge air used to prevent buildup of hydrogen gas inside the tanks. The hydrogen is generated by radiolysis of water. Third, increasing the concentration of hydroxide increases solubility of some aluminum compounds, which is desirable in processing waste. A process that converts nitrate and nitrite to hydroxide would reduce certain costs. (1) Less caustic would be purchased. (2) Some of the aluminum solid compounds in the waste tanks would become more soluble so less mass of solids would be sent to High Level Vitrification and therefore it would be not be necessary to make as much expensive high level vitrified product. (3) Less mass of sodium would be fed to Saltstone at SRS or Low Level Vitrification at Hanford Site so it would not be necessary to make as much low level product. (4) At SRS less nitrite and nitrate would be sent to Defense Waste Processing Facility (DWPF) so less formic acid would be consumed there and less hydrogen gas would be generated. This task involves literature survey of technologies to perform the nitrate to hydroxide conversion, selection of the most promising technologies, preparation of a flowsheet and design of a system. The most promising technologies are electrochemical reduction of nitrates and chemical reduction with hydrogen or ammonia. The primary reviewed technologies are listed and they aredescribed in more detail later in the report: (1) Electrochemical destruction; (2) Chemical reduction with agents such as ammonia, hydrazine or hydrogen; (3) Hydrothermal reduction process; and (4) Calcination. Only three of the technologies on the list have been demonstrated to generate usable amounts of caustic; electrochemical reduction and chemical reduction with ammonia, hydrazine or hydrogen and hydrothermal reduction. Chemical reduction with an organic reactant such as formic acid generates carbon dioxide which reacts with caustic and is thus counterproductive. Treatment of nitrate with aluminum or other active metals generates a solid product. High temperature calcination has the potential to generate sodium oxide which may be hydrated to sodium hydroxide, but this is unproven. The following criteria were developed to evaluate the most suitable option. The numbers in brackets after the criteria are relative weighting factors to account for importance: (1) Personnel exposure to radiation for installation, routine operation and maintenance; (2) Non-radioactive safety issues; (3) Whether the technology generates caustic and how many moles of caustic are generated per mole of nitrate plus nitrite decomposed; (4) Whether the technology can handle nitrate and nitrite at the concentrations encountered in waste; (5) Maturity of technology; (6) Estimated annual cost of operation (labor, depreciation, materials, utilities); (7) Capital cost; (8) Selectivity to nitrogen as decomposition product (other products are flammable and/or toxic); (9) Impact of introduced species; (10) Selectivity for destruction of nitrate vs. nitrite; and (11) Cost of deactivation and demolition. Each technology was given a score from one

  7. Molten nitrate salt technology development status report

    SciTech Connect

    Carling, R.W.; Kramer, C.M.; Bradshaw, R.W.; Nissen, D.A.; Goods, S.H.; Mar, R.W.; Munford, J.W.; Karnowsky, M.M.; Biefeld, R.N.; Norem, N.J.

    1981-03-01

    Recognizing thermal energy storage as potentially critical to the successful commercialization of solar thermal power systems, the Department of Energy (DOE) has established a comprehensive and aggressive thermal energy storage technology development program. Of the fluids proposed for heat transfer and energy storage molten nitrate salts offer significant economic advantages. The nitrate salt of most interest is a binary mixture of NaNO/sub 3/ and KNO/sub 3/. Although nitrate/nitrite mixtures have been used for decades as heat transfer and heat treatment fluids the use has been at temperatures of about 450/sup 0/C and lower. In solar thermal power systems the salts will experience a temperature range of 350 to 600/sup 0/C. Because central receiver applications place more rigorous demands and higher temperatures on nitrate salts a comprehensive experimental program has been developed to examine what effects, if any, the new demands and temperatures have on the salts. The experiments include corrosion testing, environmental cracking of containment materials, and determinations of physical properties and decomposition mechanisms. This report details the work done at Sandia National Laboratories in each area listed. In addition, summaries of the experimental programs at Oak Ridge National Laboratory, the University of New York, EIC Laboratories, Inc., and the Norwegian Institute of Technology on molten nitrate salts are given. Also discussed is how the experimental programs will influence the near-term central receiver programs such as utility repowering/industrial retrofit and cogeneration. The report is designed to provide easy access to the latest information and data on molten NaNO/sub 3//KNO/sub 3/ for the designers and engineers of future central receiver projects.

  8. Genetic basis for nitrate resistance in Desulfovibrio strains

    PubMed Central

    Korte, Hannah L.; Fels, Samuel R.; Christensen, Geoff A.; Price, Morgan N.; Kuehl, Jennifer V.; Zane, Grant M.; Deutschbauer, Adam M.; Arkin, Adam P.; Wall, Judy D.

    2014-01-01

    Nitrate is an inhibitor of sulfate-reducing bacteria (SRB). In petroleum production sites, amendments of nitrate and nitrite are used to prevent SRB production of sulfide that causes souring of oil wells. A better understanding of nitrate stress responses in the model SRB, Desulfovibrio vulgaris Hildenborough and Desulfovibrio alaskensis G20, will strengthen predictions of environmental outcomes of nitrate application. Nitrate inhibition of SRB has historically been considered to result from the generation of small amounts of nitrite, to which SRB are quite sensitive. Here we explored the possibility that nitrate might inhibit SRB by a mechanism other than through nitrite inhibition. We found that nitrate-stressed D. vulgaris cultures grown in lactate-sulfate conditions eventually grew in the presence of high concentrations of nitrate, and their resistance continued through several subcultures. Nitrate consumption was not detected over the course of the experiment, suggesting adaptation to nitrate. With high-throughput genetic approaches employing TnLE-seq for D. vulgaris and a pooled mutant library of D. alaskensis, we determined the fitness of many transposon mutants of both organisms in nitrate stress conditions. We found that several mutants, including homologs present in both strains, had a greatly increased ability to grow in the presence of nitrate but not nitrite. The mutated genes conferring nitrate resistance included the gene encoding the putative Rex transcriptional regulator (DVU0916/Dde_2702), as well as a cluster of genes (DVU0251-DVU0245/Dde_0597-Dde_0605) that is poorly annotated. Follow-up studies with individual D. vulgaris transposon and deletion mutants confirmed high-throughput results. We conclude that, in D. vulgaris and D. alaskensis, nitrate resistance in wild-type cultures is likely conferred by spontaneous mutations. Furthermore, the mechanisms that confer nitrate resistance may be different from those that confer nitrite resistance. PMID:24795702

  9. The effect of zirconium implantation on the structure of sapphire

    NASA Astrophysics Data System (ADS)

    Sina, Y.; McHargue, C. J.; Duscher, G.; Zhang, Y.

    2012-09-01

    The effect of zirconium implantation on the structure of sapphire was investigated by 175 keV Zr implantation at room temperature to a fluence of 4 × 1016 ions/cm2 into sapphire single crystals. Samples were examined by several experimental techniques: Rutherford backscattering spectroscopy along a channeling direction (RBS-C), electron-energy loss spectroscopy (EELS), and Z-contrast images obtained in an aberration-corrected scanning transmission electron microscope. Range and deposited energy were simulated with SRIM-2008.04. The Z-contrast images from transmission electron microscope indicated: a near surface damaged layer ˜30 nm thick, a subsurface region exhibiting "random" de-channeling ˜52 nm thick, and a deeper damaged, crystalline zone ˜64 nm thick. The RBS-C spectra confirmed the presence of these three regions. The two damaged regions contained high concentrations of as yet unresolved defect clusters. The intermediate region contained Zr-clusters embedded in an "amorphous" matrix that exhibited short-range order corresponding to ?-Al2O3, i.e., a defective spinel structure. The EELS measurements show that the amorphous region is deficient in oxygen.

  10. Strain effects on oxygen transport in tetragonal zirconium dioxide

    SciTech Connect

    Xian-Ming Bai; Yongfeng Zhang; Michael R. Tonks

    2013-11-01

    Temperature accelerated dynamics and molecular dynamics simulations are used to investigate the strain effects on oxygen interstitial and vacancy migration in tetragonal zirconium dioxide. At zero external strain, the anisotropic migration mechanisms of oxygen defects are characterized. At non-zero strains, both the crystal structure and defect migration barriers are modified by strain. Under compressive strains, the defect migration barrier increases with the increasing strain for both interstitials and vacancies. The crystal structure transforms from a tetragonal to a nearly cubic fluorite structure. Accordingly, the defect migration becomes nearly isotropic. Under dilative strains, the migration barrier first decreases then increases with increasing strain for both types of defects. The tetragonal phase transforms to a lower symmetry structure that is close to the orthorhombic phase. In turn, the defect migration becomes highly anisotropic. Under both compressive and dilative strains, interstitials respond to strain more strongly than vacancies. At small dilative strains, an oxygen interstitial has comparable diffusivity to a vacancy, suggesting that both types of defects can contribute to oxygen transport, if they are present. Although currently no previous result is available to validate oxygen interstitial diffusion behavior, the trend of strain effects on oxygen vacancy diffusion is in good agreement with available experimental and theoretical studies in the literature.

  11. Gadolinium-hydrogen ion exchange of zirconium phosphate

    NASA Technical Reports Server (NTRS)

    Liu, D. C.; Power, J. L.

    1972-01-01

    The Gd(+3)/H(+) ion exchange on a commercial zirconium phosphate ion exchanger was investigated in chloride, sulfate, and phosphate solutions of Gd(+3) at gadolinium concentrations of 0.001 to 1 millimole per cc and in the pH range of 0 to 3.5. Relatively low Gd(+3) capacities, in the range of 0.01 to 0.1 millimole per g of ion exchanger were found at room temperature. A significant difference in Gd(+3) sorption was observed, depending on whether the ion exchanger was converted from initial conditions of greater or lesser Gd(+3) sorption than the specific final conditions. Correlations were found between decrease in Gd(+3) capacity and loss of exchanger phosphate groups due to hydrolysis during washing and between increase in capacity and treatment with H3PO4. Fitting of the experimental data to ideal ion exchange equilibrium expressions indicated that each Gd(+3) ion is sorbed on only one site of the ion exchanger. The selectivity quotient was determined to be 2.5 + or - 0.4 at room temperature on gadolinium desorption in chloride solutions.

  12. Biologically functionalized nanochannels on ferroelectric lead zirconium titanate surfaces.

    SciTech Connect

    Ocola, L. E.; Pan, W. C.; Kuo, M.; Tirumala, V. R.; Reiss, B. D.; Firestone, M. A.; Illinois Mathematics and Science Academy

    2005-01-01

    We recently started a program at Argonne to exploit patterned, polarizable ferroelectric surfaces, such as lead zirconium titanate (PZT), as a means to create field-responsive inorganic-biomolecule interfaces to study and manipulate biomatter on surfaces. In this paper we will discuss the integration of nanochannels on the surface of PZT films and their selective functionalization to create nanovalves to control nanofluidic flow. Microfluidic devices have been fabricated using a variety of methods, ranging from thermal decomposition of buried patterned channels, to fabricating trenches via plasma etch or hot embossing followed by trench capping. Our work focuses on an alternative method by using a bilayer resist in an inverted configuration normally used for T- and Gamma- gate fabrication. This method is capable of yielding sub-100 nm nanochannels with high aspect ratios and sub-500nm alignment. We have recently demonstrated that the polarization hysteresis loop of PZT is the same before and after exposure to an aqueous environment. This opens the possibility of selective surface modification of PZT via coupling of a wide range of biomolecules (e.g., peptides, proteins) and the use of the electric-field-responsive properties of PZT to manipulate the function (e.g., orientation) of the tethered biomolecules. We have used phage display techniques to evolve specific peptide motifs that selectively bind to PZT. The optimum heptapeptide that facilitates both the attachment of functional biological molecules to the surface of PZT has been identified.

  13. SURFACE MODIFICATION OF ZIRCALOY-4 SUBSTRATES WITH NICKEL ZIRCONIUM INTERMETALLICS

    SciTech Connect

    Luscher, Walter G.; Gilbert, Edgar R.; Pitman, Stan G.; Love, Edward F.

    2013-02-01

    Surfaces of Zircaloy-4 (Zr-4) substrates were modified with nickel-zirconium (NiZr) intermetallics to tailor oxidation performance for specialized applications. Surface modification was achieved by electroplating Zr-4 substrates with nickel (Ni) and then performing thermal treatments to fully react the Ni plating with the substrates, which resulted in a coating of NiZr intermetallics on the substrate surfaces. Both plating thickness and thermal treatment were evaluated to determine the effects of these fabrication parameters on oxidation performance and to identify an optimal surface modification process. Isothermal oxidation tests were performed on surface-modified materials at 290°, 330°, and 370°C under a constant partial pressure of oxidant (i.e., 1 kPa D2O in dry Ar at 101 kPa) for 64 days. Test results revealed an enhanced, transient oxidation rate that decreased asymptotically toward the rate of the Zr-4 substrate. Oxidation kinetics were analyzed from isothermal weight gain data, which were correlated with microstructure, hydrogen pickup, strength, and hardness.

  14. The effect of zirconium implantation on the structure of sapphire

    SciTech Connect

    Sina, Younes; McHargue, Carl J; Duscher, Gerd; Zhang, Yanwen

    2012-01-01

    The effect of zirconium implantation on the structure of sapphire was investigated by 175 keV Zr implantation at room temperature to a fluence of 4 1016 ions/cm2 into sapphire single crystals. Samples were examined by several experimental techniques: Rutherford backscattering spectroscopy along a channeling direction (RBS-C), electron-energy loss spectroscopy (EELS), and Z-contrast images obtained in an aberration-corrected scanning transmission electron microscope. Range and deposited energy were simulated with SRIM-2008.04. The Z-contrast images from transmission electron microscope indicated: a near surface damaged layer ~30 nm thick, a subsurface region exhibiting "random" de-channeling ~52 nm thick, and a deeper damaged, crystalline zone ~64 nm thick. The RBS-C spectra confirmed the presence of these three regions. The two damaged regions contained high concentrations of as yet unresolved defect clusters. The intermediate region contained Zr-clusters embedded in an "amorphous" matrix that exhibited short-range order corresponding to -Al2O3, i.e., a defective spinel structure. The EELS measurements show that the amorphous region is deficient in oxygen.

  15. NMR study of hydrogen diffusion in zirconium hydride

    SciTech Connect

    Korn, C.; Goren, S.D.

    1986-01-01

    The nuclear-magnetic-resonance method was used to study the diffusion of hydrogen in zirconium hydride by measuring the temperature dependence of T/sub 1/ in a temperature range where the major relaxation mechanism was due to hydrogen diffusion. The samples investigated were ZrH/sub 1.588/, ZrH/sub 1.629/, ZrH/sub 1.684/, ZrH/sub 1.736/, ZrH/sub 1.815/, ZrH/sub 1.910/, and ZrH/sub 1.960/. These spanned both the cubic and tetragonal phases. The activation energy was found to be independent of hydrogen concentration in the cubic phase with E/sub a/ = 13.4 +- 0.4 kcal/mol and a preexponential factor given by A = (1/2)(2-x)(45 +- 10) x 10/sup 12/ Hz. In the tetragonal phase the activation energy of the bulk of the hydrogen increased modestly with concentration. In addition, it was discovered that a new very fast hydrogen channel was created by the tetragonality for approx.3% of the hydrogen. They jump with a preexponential factor that is about 2 orders of magnitude larger than that of the rest of the hydrogen. A comparison was also made between the Bloembergen-Purcell-Pound, the Barton-Sholl, and the Bustard theories for nuclear magnetic relaxation due to diffusion.

  16. NMR study of hydrogen diffusion in zirconium hydride

    NASA Astrophysics Data System (ADS)

    Korn, C.; Goren, S. D.

    1986-01-01

    The nuclear-magnetic-resonance method was used to study the diffusion of hydrogen in zirconium hydride by measuring the temperature dependence of T1 in a temperature range where the major relaxation mechanism was due to hydrogen diffusion. The samples investigated were ZrH1.588, ZrH1.629, ZrH1.684, ZrH1.736, ZrH1.815, ZrH1.910, and ZrH1.960. These spanned both the cubic and tetragonal phases. The activation energy was found to be independent of hydrogen concentration in the cubic phase with Ea=13.4+/-0.4 kcal/mol and a preexponential factor given by A=(1/2)(2-x)(45+/-10)×1012 Hz. In the tetragonal phase the activation energy of the bulk of the hydrogen increased modestly with concentration. In addition, it was discovered that a new very fast hydrogen channel was created by the tetragonality for ~3% of the hydrogen. They jump with a preexponential factor that is about 2 orders of magnitude larger than that of the rest of the hydrogen. A comparison was also made between the Bloembergen-Purcell-Pound, the Barton-Sholl, and the Bustard theories for nuclear magnetic relaxation due to diffusion.

  17. Mesoporous Zirconium Phenylenesiliconate-phosphonate Hybrids with Ordered Lamellar Nanostructures.

    PubMed

    Maeda, Kazuyuki; Kobayashi, Hiroki; Oguro, Kaku; Otsu, Masato; Kondo, Atsushi; Maki, Tei

    2015-11-16

    Novel ordered lamellar mesostructure pZrPS-2 was hydrothermally prepared by using zirconium propoxide and 4-(EtO)2 OPC6 H4 Si(OEt)3 (pPPS-E), which was hydrolyzed to organic building units substituted with both siliconate and phosphonate groups, in the presence of Cn TAB and TMAOH. The pZrPS-2 materials were obtained at a Zr/PPS ratio of 2 or higher and the basal spacing was increased by using a longer-chain surfactant (n=12-18). Removal of the occluded surfactants at 300?°C resulted in retention of the lamellar structure with negligible shrinkage of the interlayer distance. Nitrogen adsorption studies revealed the ordered mesoporous nature of pZrPS-2 with a pore diameter of approximately 2 to 3?nm. The lamellar structure is assumed to be composed of layers that include zirconia-based crystalline nanodomains and interlayer pillars mainly based on PPS units. Although lamellar structures with the same crystalline phase also formed when no surfactant was added or when the meta isomer of PPS was used, no mesoporous materials were obtained except pZrPS-2. A possible schematic model to elucidate these results is also proposed. PMID:26427615

  18. Synthesis and Characterization of Zirconium Tungstate Ultra-Thin Fibers

    SciTech Connect

    Zhang, Lifeng; Howe, Jane Y; Fong, Hao; Zhang, Yan

    2009-01-01

    This study reports an innovative method of electrospinning followed by pyrolysis to synthesize zirconium tungstate (ZrW2O8), a material with negative coefficient of thermal expansion (CTE), in ultra-thin fiber form. Morphologies and microstructures of the as-electrospun precursor fibers, the heat-treated intermediate fibers, and the final ZrW2O8 ultra-thin fibers were characterized by SEM, XRD, and TEM. The ZrW2O8 ultra-thin fibers had diameters in the sub-micrometer range with aspect ratios larger than 100; these fibers were polycrystalline, and consisted of single crystalline ZrW2O8 crystallites with sizes of 30-50 nm and surface roughness of several nanometers. The ZrW2O8 ultra-thin fibers are expected to outperform spherically, cylindrically, and/or irregularly shaped polycrystalline ZrW2O8 particles for the development of composites with precisely controlled CTEs. Additionally, this reported method could be utilized as a general approach to convert nano-scaled inorganic particles into fibers.

  19. Fracture Resistance of a Zirconium Alloy with Reoriented Hydrides

    NASA Astrophysics Data System (ADS)

    Chan, Kwai S.; He, Xihua; Pan, Yi-Ming

    2015-01-01

    Zirconium alloy cladding materials typically contain circumferential hydrides that may be reoriented to align along the radial direction when the cladding tubes are heated above and then cooled below the solvus temperature. The objectives of this study were to investigate the critical stress levels required to cause hydride reorientation (HRT) and to characterize the fracture resistance of Zircaloy-2 after hydride reorientation. HRT heat-treatment was performed on hydrogen-charged Zircaloy-2 specimens at 593 K (320 °C) or 623 K (350 °C) for 1 to 2 hours, followed by cooling to 473 K (200 °C). Fracture testing was conducted on hydride-reoriented three-point bend specimens at 473 K (200 °C) using an in situ loading stage inside a scanning electron microscope. Direct observations indicated that the reoriented hydrides, which ranged from ?1 to 22 ?m in lengths, were more prone to fracture at larger sizes (>10 ?m) compared to smaller sizes (<0.5 ?m). The reoriented hydrides reduced fracture resistance through a void nucleation, growth, and coalescence process at the crack tip. The resulting crack-resistance curves for Zircaloy-2 with reoriented hydrides decrease from 38 to 21 MPa(m)1/2 with increasing hydrogen contents from 51 to 1265 wt ppm hydrogen.

  20. Nanocrystallization of zirconium subjected to surface mechanical attrition treatment.

    PubMed

    Zhang, L; Han, Y; Lu, J

    2008-04-23

    A nanostructured surface layer with thickness of about 20 µm was formed on commercially pure zirconium using surface mechanical attrition treatment (SMAT). The microstructural features of the surface layer were systematically investigated using optical microscopy (OM), x-ray diffraction (XRD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM), respectively. Based on the results obtained, a grain refinement mechanism induced by plastic deformation during SMAT of Zr is proposed. At the initial stage of SMAT, twinning dominates the plastic deformation of Zr and divides the coarse grains of Zr into finer twin plates. With increasing strain, intersection of twins occurs, and dislocation slips are activated, becoming the predominant deformation mode instead of twinning. As a result of the dislocation slips, high-density dislocation arrays are formed, which further subdivide the twin plates into subgrains of size about 200-400 nm. With a further increase of strain, the dislocations accumulate and rearrange to minimize the energy state of the high-strain-energy subgrains, the dense dislocation walls convert to grain boundaries, and the submicronic grains are subdivided, leading to the formation of nanosized grains at the top of the treated surface. PMID:21825658

  1. Hopping conduction in zirconium oxynitrides thin film deposited by reactive magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Guo, Jie; Zhan, Guanghui; Liu, Jingquan; Yang, Bin; Xu, Bin; Feng, Jie; Chen, Xiang; Yang, Chunsheng

    2015-10-01

    Zirconium oxynitrides thin film thermometers were demonstrated to be useful temperature sensors. However, the basic conduction mechanism of zirconium oxynitrides films has been a long-standing issue, which hinders the prediction and optimization of their ultimate performance. In this letter, zirconium oxynitrides films were grown on sapphire substrates by magnetron sputtering and their electric transport mechanism has been systemically investigated. It was found that in high temperatures region (>150 K) the electrical conductivity was dominated by thermal activation for all samples. In the low temperatures range, while Mott variable hopping conduction (VRH) was dominated the transport for films with relatively low resistance, a crossover from Mott VRH conduction to Efros-Shklovskii (ES) VRH was observed for films with relatively high resistance. This low temperature crossover from Mott to ES VRH indicates the presence of a Coulomb gap (~7 meV). These results demonstrate the competing and tunable conduction mechanism in zirconium oxynitrides thin films, which would be helpful for optimizing the performance of zirconium oxynitrides thermometer.

  2. Synthesis of zirconium tungstate-zirconia core-shell composite particles

    SciTech Connect

    Khazeni, Nasser; Mavis, Bora; Guenduez, Guengoer; Colak, Uner

    2011-11-15

    Highlights: {yields} ZrW{sub 2}O{sub 8}-ZrO{sub 2} core-shell particles to offer solutions for sintering problems. {yields} Core synthesis by a precursor based on tungstic acid and zirconium acetate. {yields} Shell phase by urea hydrolysis in the presence of zirconium ions. {yields} [Urea]/[ZrOCl{sub 2}] ratio controls the rate of shell precursor precipitation. -- Abstract: In this work, ZrW{sub 2}O{sub 8}-ZrO{sub 2} core-shell composite particles were synthesized. ZrW{sub 2}O{sub 8} that was used in the core is a material with negative coefficient of thermal expansion, and it was synthesized from a high-pH precursor based on use of tungstic acid and zirconium acetate. Shell layer was composed of ZrO{sub 2} nanocrystallites and precipitated from an aqueous solution by urea hydrolysis. While volume of the shell was effectively controlled by the initial zirconium ion concentration in the solutions, the rate of precipitation was a function of the ratio of initial concentrations of urea to zirconium ions. It is hypothesized that isolation of the ZrW{sub 2}O{sub 8} within a layer of ZrO{sub 2}, will be a key element in solving problems associated with reactivity of ZrW{sub 2}O{sub 8} towards other components in sintering of ceramic-ceramic composites with tuned or zero thermal expansion coefficient.

  3. Zirconium-based alloys, nuclear fuel rods and nuclear reactors including such alloys, and related methods

    DOEpatents

    Mariani, Robert Dominick

    2014-09-09

    Zirconium-based metal alloy compositions comprise zirconium, a first additive in which the permeability of hydrogen decreases with increasing temperatures at least over a temperature range extending from 350.degree. C. to 750.degree. C., and a second additive having a solubility in zirconium over the temperature range extending from 350.degree. C. to 750.degree. C. At least one of a solubility of the first additive in the second additive over the temperature range extending from 350.degree. C. to 750.degree. C. and a solubility of the second additive in the first additive over the temperature range extending from 350.degree. C. to 750.degree. C. is higher than the solubility of the second additive in zirconium over the temperature range extending from 350.degree. C. to 750.degree. C. Nuclear fuel rods include a cladding material comprising such metal alloy compositions, and nuclear reactors include such fuel rods. Methods are used to fabricate such zirconium-based metal alloy compositions.

  4. Separation of hafnium from zirconium in sulfuric acid solutions using pressurized ion exchange

    SciTech Connect

    Hurst, F.J.

    1981-01-01

    High-resolution pressurized ion exchange has been used successfully to study and separate hafnium and zirconium sulfate complexes by chromatographic elution from Dowex 50W-X8 (15 to 25 ..mu..m) resin with sulfuric acid solutions. Techniques were developed to continuously monitor the column effluents for zirconium and hafnium by reaction with fluorometric and colorimetric reagents. Since neither reagent was specific for either metal ion, peak patterns were initially identified by using the stable isotopes /sup 90/Zr and /sup 180/Hf as fingerprints of their elution position. Distribution ratios for both zirconium and hafnium decrease as the inverse fourth power of the sulfuric acid concentration below 2N and as the inverse second power at higher acid concentration. The hafnium-to-zirconium separation factor is approximately constant (approx. 8) over the 0.5 to 3N range. Under certain conditions, an unseparated fraction was observed that was not retained by the resin. The amount of this fraction which is thought to be a polymeric hydrolysis product appears to be a function of metal and sulfuric acid concentrations. Conditions are being sought to give the highest zirconium concentration and the lowest acid concentration that can be used as a feed material for commercial scale-up in the continuous annular chromatographic (CAC) unit without formation of the polymer.

  5. Open-Source Photometric System for Enzymatic Nitrate Quantification

    PubMed Central

    Wittbrodt, B. T.; Squires, D. A.; Walbeck, J.; Campbell, E.; Campbell, W. H.; Pearce, J. M.

    2015-01-01

    Nitrate, the most oxidized form of nitrogen, is regulated to protect people and animals from harmful levels as there is a large over abundance due to anthropogenic factors. Widespread field testing for nitrate could begin to address the nitrate pollution problem, however, the Cadmium Reduction Method, the leading certified method to detect and quantify nitrate, demands the use of a toxic heavy metal. An alternative, the recently proposed Environmental Protection Agency Nitrate Reductase Nitrate-Nitrogen Analysis Method, eliminates this problem but requires an expensive proprietary spectrophotometer. The development of an inexpensive portable, handheld photometer will greatly expedite field nitrate analysis to combat pollution. To accomplish this goal, a methodology for the design, development, and technical validation of an improved open-source water testing platform capable of performing Nitrate Reductase Nitrate-Nitrogen Analysis Method. This approach is evaluated for its potential to i) eliminate the need for toxic chemicals in water testing for nitrate and nitrite, ii) reduce the cost of equipment to perform this method for measurement for water quality, and iii) make the method easier to carryout in the field. The device is able to perform as well as commercial proprietary systems for less than 15% of the cost for materials. This allows for greater access to the technology and the new, safer nitrate testing technique. PMID:26244342

  6. Open-Source Photometric System for Enzymatic Nitrate Quantification.

    PubMed

    Wittbrodt, B T; Squires, D A; Walbeck, J; Campbell, E; Campbell, W H; Pearce, J M

    2015-01-01

    Nitrate, the most oxidized form of nitrogen, is regulated to protect people and animals from harmful levels as there is a large over abundance due to anthropogenic factors. Widespread field testing for nitrate could begin to address the nitrate pollution problem, however, the Cadmium Reduction Method, the leading certified method to detect and quantify nitrate, demands the use of a toxic heavy metal. An alternative, the recently proposed Environmental Protection Agency Nitrate Reductase Nitrate-Nitrogen Analysis Method, eliminates this problem but requires an expensive proprietary spectrophotometer. The development of an inexpensive portable, handheld photometer will greatly expedite field nitrate analysis to combat pollution. To accomplish this goal, a methodology for the design, development, and technical validation of an improved open-source water testing platform capable of performing Nitrate Reductase Nitrate-Nitrogen Analysis Method. This approach is evaluated for its potential to i) eliminate the need for toxic chemicals in water testing for nitrate and nitrite, ii) reduce the cost of equipment to perform this method for measurement for water quality, and iii) make the method easier to carryout in the field. The device is able to perform as well as commercial proprietary systems for less than 15% of the cost for materials. This allows for greater access to the technology and the new, safer nitrate testing technique. PMID:26244342

  7. Understanding nitrate assimilation and its regulation in microalgae

    PubMed Central

    Sanz-Luque, Emanuel; Chamizo-Ampudia, Alejandro; Llamas, Angel; Galvan, Aurora; Fernandez, Emilio

    2015-01-01

    Nitrate assimilation is a key process for nitrogen (N) acquisition in green microalgae. Among Chlorophyte algae, Chlamydomonas reinhardtii has resulted to be a good model system to unravel important facts of this process, and has provided important insights for agriculturally relevant plants. In this work, the recent findings on nitrate transport, nitrate reduction and the regulation of nitrate assimilation are presented in this and several other algae. Latest data have shown nitric oxide (NO) as an important signal molecule in the transcriptional and posttranslational regulation of nitrate reductase and inorganic N transport. Participation of regulatory genes and proteins in positive and negative signaling of the pathway and the mechanisms involved in the regulation of nitrate assimilation, as well as those involved in Molybdenum cofactor synthesis required to nitrate assimilation, are critically reviewed. PMID:26579149

  8. Cold neutron prompt gamma activation analysis, a non-destructive technique for hydrogen level assessment in zirconium alloys

    E-print Network

    Motta, Arthur T.

    assessment in zirconium alloys Adrien Couet a, , Arthur T. Motta a , Robert J. Comstock b , Rick L. Paul c to quantitatively assess hydrogen concentration in zirconium alloys. The technique, called Cold Neutron Prompt Gamma alloy nuclear fuel cladding and the associated hydrogen pick-up can become a life-limiting degradation

  9. Seasonal nitrate algorithms for nitrate retrieval using OCEANSAT-2 and MODIS-AQUA satellite data.

    PubMed

    Durairaj, Poornima; Sarangi, Ranjit Kumar; Ramalingam, Shanthi; Thirunavukarassu, Thangaradjou; Chauhan, Prakash

    2015-04-01

    In situ datasets of nitrate, sea surface temperature (SST), and chlorophyll a (chl a) collected during the monthly coastal samplings and organized cruises along the Tamilnadu and Andhra Pradesh coast between 2009 and 2013 were used to develop seasonal nitrate algorithms. The nitrate algorithms have been built up based on the three-dimensional regressions between SST, chl a, and nitrate in situ data using linear, Gaussian, Lorentzian, and paraboloid function fittings. Among these four functions, paraboloid was found to be better with the highest co-efficient of determination (postmonsoon: R2=0.711, n=357; summer: R2=0.635, n=302; premonsoon: R2=0.829, n=249; and monsoon: R2=0.692, n=272) for all seasons. Based on these fittings, seasonal nitrate images were generated using the concurrent satellite data of SST from Moderate Resolution Imaging Spectroradiometer (MODIS) and chlorophyll (chl) from Ocean Color Monitor (OCM-2) and MODIS. The best retrieval of modeled nitrate (R2=0.527, root mean square error (RMSE)=3.72, and mean normalized bias (MNB)=0.821) was observed for the postmonsoon season due to the better retrieval of both SST MODIS (28 February 2012, R2=0.651, RMSE=2.037, and MNB=0.068) and chl OCM-2 (R2=0.534, RMSE=0.317, and MNB=0.27). Present results confirm that the chl OCM-2 and SST MODIS retrieve nitrate well than the MODIS-derived chl and SST largely due to the better retrieval of chl by OCM-2 than MODIS. PMID:25762424

  10. Gas phase chemistry of chlorine nitrate

    SciTech Connect

    Okumura, M.; Moore, T.A.; Crellin, K.C.

    1995-12-31

    Chlorine nitrate (ClONO{sub 2}) is a reservoir of both ClO{sub x} and NO{sub x} radicals in Earth`s stratosphere, and its decomposition is important in determining the abundance of stratospheric ozone. We present experimental and theoretical studies that explore the mechanisms and dynamics of processes leading to ClONO{sub 2} destruction in the stratosphere. Molecular beam photodissociation experiments have been performed to determine the decomposition pathways of ClONO{sub 2} upon excitation at 308 nm and to explore the possibility of a long-lived excited state. We have also investigated the reaction of chlorine nitrate with chloride ions Cl{sup -} in the gas phase. The gas phase ionic reaction may elucidate ionic mechanisms of heterogeneous reactions occurring on the surfaces of Polar Stratospheric Cloud particles and also raise doubts about proposed schemes to mitigate ozone depletion by electrifying the stratosphere.

  11. Photolysis of alkaline-earth nitrates

    NASA Astrophysics Data System (ADS)

    Kriger, L. D.; Miklin, M. B.; Dyagileva, E. P.; Anan'ev, V. A.

    2013-02-01

    Peroxynitrite and nitrite ions are the diamagnetic products of photolysis (with light at a wavelength of 253.7 nm) of alkaline-earth nitrates; the paramagnetic products and hydrogen peroxide were not found. The structural water in alkaline-earth nitrate crystals did not affect the qualitative composition of the photodecomposition products. The quantum yield of nitrite ions was 0.0012, 0.0038, 0.0078, and 0.0091 quanta-1 and that of peroxynitrite ions was 0.0070, 0.0107, 0.0286, and 0.0407 quanta-1 for Sr(NO3)2, Ba(NO3)2, Ca(NO3)2 · 4H2O, and Mg(NO3)2 · 6H2O, respectively.

  12. Supplemental Cooling for Nitrate Salt Waste

    SciTech Connect

    Goldberg, Mitchell S.

    2015-08-19

    In July 2015, Los Alamos National Laboratory completed installation of a supplemental cooling system in the structure where remediated nitrate salt waste drums are stored. Although the waste currently is in a safe configuration and is monitored daily,controlling the temperature inside the structure adds another layer of protection for workers, the public,and the environment.This effort is among several layers of precautions designed to secure the waste.

  13. Phase transitions in calcium nitrate thin films.

    PubMed

    Al-Abadleh, Hind A; Krueger, B J; Ross, J L; Grassian, V H

    2003-11-21

    Calcium carbonate is a ubiquitous mineral and its reactivity with indoor and outdoor air pollutants will contribute to the deterioration of these materials through the formation of salts that deliquesce at low relative humidity (RH). As shown here for calcium nitrate thin films, deliquescence occurs at even lower relative humidity than expected from bulk thermodynamics and lower than the recommended humidity for the preservation of artifacts and antiques. PMID:14651109

  14. Potential of dietary nitrate in angiogenesis.

    PubMed

    Rammos, Christos; Luedike, Peter; Hendgen-Cotta, Ulrike; Rassaf, Tienush

    2015-10-26

    Endothelial dysfunction with impaired bioavailability of nitric oxide (NO) is the hallmark in the development of cardiovascular disease. Endothelial dysfunction leads to atherosclerosis, characterized by chronic inflammation of the arterial wall and stepwise narrowing of the vessel lumen. Atherosclerosis causes deprivation of adequate tissue blood flow with compromised oxygen supply. To overcome this undersupply, remodeling of the vascular network is necessary to reconstitute and sustain tissue viability. This physiological response is often not sufficient and therapeutic angiogenesis remains an unmet medical need in critical limb ischemia or coronary artery disease. Feasible approaches to promote blood vessel formation are sparse. Administration of pro-angiogenic factors, gene therapy, or targeting of microRNAs has not yet entered the daily practice. Nitric oxide is an important mediator of angiogenesis that becomes limited under ischemic conditions and the maintenance of NO availability might constitute an attractive therapeutic target. Until recently it was unknown how the organism provides NO under ischemia. In recent years it could be demonstrated that NO can be formed independently of its enzymatic synthesis in the endothelium by reduction of inorganic nitrite under hypoxic conditions. Circulating nitrite derives from oxidation of NO or reduction of inorganic nitrate by commensal bacteria in the oral cavity. Intriguingly, nitrate is a common constituent of our everyday diet and particularly high concentrations are found in leafy green vegetables such as spinach, lettuce, or beetroot. Evidence suggests that dietary nitrate supplementation increases the regenerative capacity of ischemic tissue and that this effect may offer an attractive nutrition-based strategy to improve ischemia-induced revascularization. We here summarize and discuss the regenerative capacity of dietary nitrate on the vascular system. PMID:26516419

  15. Potential of dietary nitrate in angiogenesis

    PubMed Central

    Rammos, Christos; Luedike, Peter; Hendgen-Cotta, Ulrike; Rassaf, Tienush

    2015-01-01

    Endothelial dysfunction with impaired bioavailability of nitric oxide (NO) is the hallmark in the development of cardiovascular disease. Endothelial dysfunction leads to atherosclerosis, characterized by chronic inflammation of the arterial wall and stepwise narrowing of the vessel lumen. Atherosclerosis causes deprivation of adequate tissue blood flow with compromised oxygen supply. To overcome this undersupply, remodeling of the vascular network is necessary to reconstitute and sustain tissue viability. This physiological response is often not sufficient and therapeutic angiogenesis remains an unmet medical need in critical limb ischemia or coronary artery disease. Feasible approaches to promote blood vessel formation are sparse. Administration of pro-angiogenic factors, gene therapy, or targeting of microRNAs has not yet entered the daily practice. Nitric oxide is an important mediator of angiogenesis that becomes limited under ischemic conditions and the maintenance of NO availability might constitute an attractive therapeutic target. Until recently it was unknown how the organism provides NO under ischemia. In recent years it could be demonstrated that NO can be formed independently of its enzymatic synthesis in the endothelium by reduction of inorganic nitrite under hypoxic conditions. Circulating nitrite derives from oxidation of NO or reduction of inorganic nitrate by commensal bacteria in the oral cavity. Intriguingly, nitrate is a common constituent of our everyday diet and particularly high concentrations are found in leafy green vegetables such as spinach, lettuce, or beetroot. Evidence suggests that dietary nitrate supplementation increases the regenerative capacity of ischemic tissue and that this effect may offer an attractive nutrition-based strategy to improve ischemia-induced revascularization. We here summarize and discuss the regenerative capacity of dietary nitrate on the vascular system. PMID:26516419

  16. Vapor transport of zirconium and silicon during heat-treatment of Zircaloy in silica

    SciTech Connect

    Knittel, D.R.; Cubicciotti, D.

    1980-01-01

    When pieces of Zircaloy are heated above 600/sup 0/C in sealed silica capsules, silicon is deposited on the Zircaloy surface as zirconium silicides and zirconium is deposited on the silica in two forms: as an oxide layer in the high temperature region and as a metallic mirror on lower temperature surfaces. Samples of Zircaloy were heated in silica capsules under various conditions and analyzed by scanning electron microscopy. The results indicate that the deposits resulted from vapor transport processes involving volatile zirconium and silicon fluorides. Residual fluoride on Zircaloy surfaces, remaining from acid pickling treatments, was observed by Auger electron spectroscopy and mass spectroscopy in amounts sufficient to cause the transport. The thermodynamics of the vapor transport reactions are in accord with the fluoride mechanism. 4 figures.

  17. Comparative behavior of titanium and zirconium in hydrofluoric-nitric acid pickling solutions

    SciTech Connect

    Sutter, E.M.M.; Hlawka, F.; Cornet, A. )

    1990-07-01

    The different behavior of titanium and zirconium in HF-HNO{sub 3} pickling solutions has been studied using electrochemical methods and Raman spectrometry. In each case, the depleting of the solutions during a pickling experiment could be correlated with the consumption of HF to form metal oxo or oxofluoro complexes. However, the mechanism of metal dissolution is quite different for the two metals. The titanium dissolution process in such solutions can be interpreted using a passivation model in which dissolution and passivation are two competing reactions at the surface of the bare metal. On the other hand, zirconium dissolution occurs through formation of an oxide film with ionic diffusion through the film being a rate-determining step. The particular role of strong acid added to the HF solution for pickling of titanium and zirconium is also discussed.

  18. Determination of fluoride in water - A modified zirconium-alizarin method

    USGS Publications Warehouse

    Lamar, W.L.

    1945-01-01

    A convenient, rapid colorimetric procedure using the zirconium-alizarin indicator acidified with sulfuric acid for the determination of fluoride in water is described. Since this acid indicator is stable indefinitely, it is more useful than other zirconium-alizarin reagents previously reported. The use of sulfuric acid alone in acidifying the zirconium-alizarin reagent makes possible the maximum suppression of the interference of sulfate. Control of the pH of the samples eliminates errors due to the alkalinity of the samples. The fluoride content of waters containing less than 500 parts per million of sulfate and less than 1000 p.p.m. of chloride may be determined within a limit of 0.1 p.p.m. when a 100-ml. sample is used.

  19. Ion processing of zirconium ceramics by high-power pulsed beams

    NASA Astrophysics Data System (ADS)

    Ghyngazov, S. A.; Vasil'ev, I. P.; Surzhikov, A. P.; Frangulyan, T. S.; Chernyavskii, A. V.

    2015-01-01

    Modification of the structural phase state of the surface layer of zirconium ceramics irradiated by high-power pulsed beams of carbon ions at a pulse energy density of 3 J/cm2 is revealed using X-ray phase analysis and scanning electron microscopy. The analysis of roentgenograms indicates efficient formation of the high-temperature cubic modification of zirconium dioxide. The study of the depth distribution of oxygen ions using the secondary ion mass spectroscopy yields deficit of oxygen in the surface layer of the irradiated ceramics. A violation of the oxygen stoichiometry leads to a significant (by several orders of magnitude) increase in the conductivity of the samples under study. Mechanical characteristics (microhardness, nanohardness, and Young modulus) of the zirconium ceramics are determined after processing with high-power pulsed beams.

  20. Nitrate destruction by a plasma torch

    SciTech Connect

    Falk, D.E.; Lahoda, E.J.; Mitchell, J.L.

    1988-09-01

    This report presents the results of a test program which investigated the feasibility of a plasma-based system to process metal nitrate wastes by transforming them into the corresponding metal oxides and separating these oxides from the gas stream. The test program included performing a thermodynamic study of the proposed process, design and preparation of the actual test program, performance of that test, analyzing the results of the test, and documenting the results of the program in this report. The test was performed for the Westinghouse Materials Company of Ohio (WMCO) by the Westinghouse Environmental Technology Division (now the Environmental Services Division). All testing was completed at the Plasma Center located at the Westinghouse Waltz Mill Site, Madison, Pennsylvania. The primary objective of this proof-of-principle experiment was to demonstrate that raffinate solutions containing nitric acid and various metal nitrates, when treated in a plasma torch reactor, would decompose the nitrates to oxides and that the product solid metal oxides could be separated from the gaseous product nitrogen oxides. 15 figs., 10 tabs.

  1. Solid-phase zirconium and fluoride species in alkaline zircaloy cladding waste at Hanford.

    PubMed

    Reynolds, Jacob G; Huber, Heinz J; Cooke, Gary A; Pestovich, John A

    2014-08-15

    The United States Department of Energy Hanford Site, near Richland, Washington, USA, processed plutonium between 1944 and 1987. Fifty-six million gallons of waste of various origins remain, including waste from removing zircaloy fuel cladding using the so-called Zirflex process. The speciation of zirconium and fluoride in this waste is important because of the corrosivity and reactivity of fluoride as well as the (potentially) high density of Zr-phases. This study evaluates the solid-phase speciation of zirconium and fluoride using X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). Two waste samples were analyzed: one waste sample that is relatively pure zirconium cladding waste from tank 241-AW-105 and another that is a blend of zirconium cladding wastes and other high-level wastes from tank 241-C-104. Villiaumite (NaF) was found to be the dominant fluoride species in the cladding waste and natrophosphate (Na7F[PO4]2 · 19H2O) was the dominant species in the blended waste. Most zirconium was present as a sub-micron amorphous Na-Zr-O phase in the cladding waste and a Na-Al-Zr-O phase in the blended waste. Some zirconium was present in both tanks as either rounded or elongated crystalline needles of Na-bearing ZrO2 that are up to 200 ?m in length. These results provide waste process planners the speciation data needed to develop disposal processes for this waste. PMID:24976128

  2. Nitrate removal using different carbon substrates in a laboratory model.

    PubMed

    Hashemi, Seyyed Ebrahim; Heidarpour, Manouchehr; Mostafazadeh-Fard, Behrouz

    2011-01-01

    Agricultural fields have been frequently identified as major contributors of nitrate leaching into surface and ground waters. Tile drains can act as direct pathways, transferring leached nitrate to surface water. Bioreactor filters are useful for the removal of nitrate from drainage waters; however, these filters require an external carbon supply to sustain denitrification. In this study, four organic carbon sources including wood, barley straw, rice husks, and date palm leaf, were used to enhance denitrification and the effects of water velocity and influent nitrate concentration on the nitrate removal were evaluated. Cumulative nitrate removal was highest for the date palm leaf treatments and was lowest for the wood treatments. The effects were in decreasing order for date palm leaf, barley straw, rice husks, and wood, respectively. The performance of the biofilters improved with increasing influent nitrate concentration and decreasing water velocity, allowing for high nitrate removal rates to be achieved. The results showed that all of the treatments had reduced the effluent nitrate concentrations below the USEPA maximum contaminant level for drinking water of 45 mg L(-1) nitrate at the end of the study. PMID:22049767

  3. Growing patterns to produce 'nitrate-free' lettuce (Lactuca sativa).

    PubMed

    Croitoru, Mircea Dumitru; Muntean, Daniela-Lucia; Fülöp, Ibolya; Modroiu, Adriana

    2015-01-01

    Vegetables can contain significant amounts of nitrate and, therefore, may pose health hazards to consumers by exceeding the accepted daily intake for nitrate. Different hydroponic growing patterns were examined in this work in order to obtain 'nitrate-free lettuces'. Growing lettuces on low nitrate content nutrient solution resulted in a significant decrease in lettuces' nitrate concentrations (1741 versus 39 mg kg(-1)), however the beneficial effect was cancelled out by an increase in the ambient temperature. Nitrate replacement with ammonium was associated with an important decrease of the lettuces' nitrate concentration (from 1896 to 14 mg kg(-1)) and survival rate. An economically feasible method to reduce nitrate concentrations was the removal of all inorganic nitrogen from the nutrient solution before the exponential growth phase. This method led to lettuces almost devoid of nitrate (10 mg kg(-1)). The dried mass and calcinated mass of lettuces, used as markers of lettuces' quality, were not influenced by this treatment, but a small reduction (18%, p < 0.05) in the fresh mass was recorded. The concentrations of nitrite in the lettuces and their modifications are also discussed in the paper. It is possible to obtain 'nitrate-free' lettuces in an economically feasible way. PMID:25345876

  4. New phosphanyl-substituted titanium and zirconium alkoxide precursors for sol-gel processing

    SciTech Connect

    Lorenz, A.; Schubert, U.

    1996-12-31

    Zirconium and titanium alkoxide derivatives with phosphanyl substituents were synthesized by reaction of the alkoxides with 2-acrylamido-2-methyl-propane sulfonic acid followed by addition of HPPh{sub 2} to the acrylic double bond. Alternatively, the phosphinated sulfonic acid was prepared first and then reacted with the alkoxides. The second route is preferred because of the milder reaction conditions, shorter reaction times and avoidance of byproducts. The bifunctional organic ligand is bonded to the titanium or zirconium atom via the sulfonate group, while the PR{sub 2} group is available for further reactions such as the coordination of metal compounds.

  5. Thermal expansion behaviour of sodium zirconium phosphate structure type phosphates containing tin

    SciTech Connect

    Buvaneswari, G.; Govindan Kutty, K.V.; Varadaraju, U.V

    2004-03-01

    Thermal expansion behaviour of sodium zirconium phosphate structure type phosphates of the formula AM{sup 3+}SnP{sub 3}O{sub 12} (A=Ca, Sr and Ba; M{sup 3+}=Cr and Fe) was studied by high temperature X-ray diffraction and dilatometry in the temperature range 298-1073 K. The variation in the hexagonal lattice parameters of the Ca-containing compounds is in line with the 'sodium zirconium phosphate behaviour'. However, the strontium- and barium-containing compounds display an altogether different behaviour of axial expansion. The results are explained based on the crystal chemistry of these compounds.

  6. Bonding of sapphire to sapphire by eutectic mixture of aluminum oxide and zirconium oxide

    NASA Technical Reports Server (NTRS)

    Deluca, J. J. (inventor)

    1979-01-01

    An element comprising sapphire, ruby or blue sapphire can be bonded to another element of such material with a eutectic mixture of aluminum oxide and zirconium oxide. The bonding mixture may be applied in the form of a distilled water slurry or by electron beam vapor deposition. In one embodiment the eutectic is formed in situ by applying a layer of zirconium oxide and then heating the assembly to a temperature above the eutectic temperature and below the melting point of the material from which the elements are formed. The formation of a sapphire rubidium maser cell utilizing eutectic bonding is shown.

  7. Zirconium-modified materials for selective adsorption and removal of aqueous arsenic

    DOEpatents

    Zhao, Hongting; Moore, Robert C.

    2004-11-30

    A method, composition, and apparatus for removing contaminant species from an aqueous medium comprising: providing a material to which zirconium has been added, the material selected from one or more of zeolites, cation-exchangeable clay minerals, fly ash, mesostructured materials, activated carbons, cellulose acetate, and like porous and/or fibrous materials; and contacting the aqueous medium with the material to which zirconium has been added. The invention operates on all arsenic species in the form of arsenate, arsenite and organometallic arsenic, with no pretreatment necessary (e.g., oxidative conversion of arsenite to arsenate).

  8. The fate of nitrate in intertidal permeable sediments.

    PubMed

    Marchant, Hannah K; Lavik, Gaute; Holtappels, Moritz; Kuypers, Marcel M M

    2014-01-01

    Coastal zones act as a sink for riverine and atmospheric nitrogen inputs and thereby buffer the open ocean from the effects of anthropogenic activity. Recently, microbial activity in sandy permeable sediments has been identified as a dominant source of N-loss in coastal zones, namely through denitrification. Some of the highest coastal denitrification rates measured so far occur within the intertidal permeable sediments of the eutrophied Wadden Sea. Still, denitrification alone can often account for only half of the substantial nitrate (NO3-) consumption. Therefore, to investigate alternative NO3- sinks such as dissimilatory nitrate reduction to ammonium (DNRA), intracellular nitrate storage by eukaryotes and isotope equilibration effects we carried out 15NO3- amendment experiments. By considering all of these sinks in combination, we could quantify the fate of the 15NO3- added to the sediment. Denitrification was the dominant nitrate sink (50-75%), while DNRA, which recycles N to the environment accounted for 10-20% of NO3- consumption. Intriguingly, we also observed that between 20 and 40% of 15NO3- added to the incubations entered an intracellular pool of NO3- and was subsequently respired when nitrate became limiting. Eukaryotes were responsible for a large proportion of intracellular nitrate storage, and it could be shown through inhibition experiments that at least a third of the stored nitrate was subsequently also respired by eukaryotes. The environmental significance of the intracellular nitrate pool was confirmed by in situ measurements which revealed that intracellular storage can accumulate nitrate at concentrations six fold higher than the surrounding porewater. This intracellular pool is so far not considered when modeling N-loss from intertidal permeable sediments; however it can act as a reservoir for nitrate during low tide. Consequently, nitrate respiration supported by intracellular nitrate storage can add an additional 20% to previous nitrate reduction estimates in intertidal sediments, further increasing their contribution to N-loss. PMID:25127459

  9. Nitrate ammonification in mangrove soils: a hidden source of nitrite?

    PubMed Central

    Balk, Melike; Laverman, Anniet M.; Keuskamp, Joost A.; Laanbroek, Hendrikus J.

    2015-01-01

    Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought to be the preferential pathway of nitrate reduction. Mangrove forest mutually differ in their productivity, which may lead to different available carbon to nitrate ratios in their soil. Hence, nitrate ammonification is expected to be of more importance in high- compared to low-productive forests. The hypothesis was tested in flow-through reactors that contain undisturbed mangrove soils from high-productive Avicennia germinans and Rhizophora mangle forests in Florida and low-productive Avicennia marina forests in Saudi Arabia. Nitrate was undetectable in the soils from both regions. It was assumed that a legacy of nitrate ammonification would be reflected by a higher ammonium production from these soils upon the addition of nitrate. Unexpectedly, the soils from the low-productive forests in Saudi Arabia produced considerably more ammonium than the soils from the high-productive forests in Florida. Hence, other environmental factors than productivity must govern the selection of nitrate ammonification or denitrification. A rather intriguing observation was the 1:1 production of nitrite and ammonium during the consumption of nitrate, more or less independent from sampling region, location, sampling depth, mangrove species and from the absence or presence of additional degradable carbon. This 1:1 ratio points to a coupled production of ammonium and nitrite by one group of nitrate-reducing microorganisms. Such a production of nitrite will be hidden by the presence of active nitrite-reducing microorganisms under the nitrate-limited conditions of most mangrove forest soils. PMID:25784903

  10. The Fate of Nitrate in Intertidal Permeable Sediments

    PubMed Central

    Marchant, Hannah K.; Lavik, Gaute; Holtappels, Moritz; Kuypers, Marcel M. M.

    2014-01-01

    Coastal zones act as a sink for riverine and atmospheric nitrogen inputs and thereby buffer the open ocean from the effects of anthropogenic activity. Recently, microbial activity in sandy permeable sediments has been identified as a dominant source of N-loss in coastal zones, namely through denitrification. Some of the highest coastal denitrification rates measured so far occur within the intertidal permeable sediments of the eutrophied Wadden Sea. Still, denitrification alone can often account for only half of the substantial nitrate (NO3?) consumption. Therefore, to investigate alternative NO3? sinks such as dissimilatory nitrate reduction to ammonium (DNRA), intracellular nitrate storage by eukaryotes and isotope equilibration effects we carried out 15NO3? amendment experiments. By considering all of these sinks in combination, we could quantify the fate of the 15NO3? added to the sediment. Denitrification was the dominant nitrate sink (50–75%), while DNRA, which recycles N to the environment accounted for 10–20% of NO3? consumption. Intriguingly, we also observed that between 20 and 40% of 15NO3? added to the incubations entered an intracellular pool of NO3? and was subsequently respired when nitrate became limiting. Eukaryotes were responsible for a large proportion of intracellular nitrate storage, and it could be shown through inhibition experiments that at least a third of the stored nitrate was subsequently also respired by eukaryotes. The environmental significance of the intracellular nitrate pool was confirmed by in situ measurements which revealed that intracellular storage can accumulate nitrate at concentrations six fold higher than the surrounding porewater. This intracellular pool is so far not considered when modeling N-loss from intertidal permeable sediments; however it can act as a reservoir for nitrate during low tide. Consequently, nitrate respiration supported by intracellular nitrate storage can add an additional 20% to previous nitrate reduction estimates in intertidal sediments, further increasing their contribution to N-loss. PMID:25127459

  11. Nitrate induced regulation of nodule formation in soybean. [Bradyrhizobium japonicum

    SciTech Connect

    Malik, N.S.A.; Calvert, H.E.; Bauer, W.D.

    1987-06-01

    Nodule formation was inhibited by exposing soybean plants to nitrate in plastic growth pouches. Exposure to 15 millimolar nitrate results in a 2.5-fold decrease in the number of nodules formed in the region of the primary root above the mark made at the time of inoculation to indicate the position of the root tip. Serial section analysis of Bradyrhizobium infections in this region revealed that infection initiation was inhibited approximately 3-fold by exposure to nitrate. Both initial cortical cell divisions and infection thread formation were inhibited. If exposure to nitrate was delayed for 18 hours after the time of inoculation, inhibition was much reduced. This indicates that most of the nitrate-sensitive events of infection were functionally complete within less than 18 hours. Exposure to nitrate for periods of 4 to 24 hours after inoculation, followed by transfer to no-nitrate conditions for the remainder of the time, did not result in substantial inhibition of nodule number. This indicates that the effects of nitrate on infection initiation can be almost entirely reversible. Split towel pouches were used to physically separate portions of the primary root exposed to nitrate and portions of the root exposed to rhizobia. In experiments where nitrate was applied either below or above the inoculated region of the primary root, the degree of inhibition of nodulation was not correlated with either the external concentration of nitrate in contact with root cells undergoing infection or with the internal concentration of nitrate in the infectible region of the root. These results indicate that nitrate itself may not directly inhibit the infection initiation or induce host regulatory responses.

  12. The initial, thermal oxidation of zirconium at room temperature

    NASA Astrophysics Data System (ADS)

    Lyapin, A.; Jeurgens, L. P. H.; Graat, P. C. J.; Mittemeijer, E. J.

    2004-12-01

    Angle-resolved x-ray photoelectron spectroscopy (ARXPS) and in situ spectroscopic ellipsometry have been used to investigate the initial oxidation of polycrystalline zirconium at room temperature in the partial oxygen pressure range of 1.3×10-7-1.3×10-4Pa. Detailed quantitative analysis of the measured Zr3d ARXPS spectra of the oxidized metal allowed separation of the intrinsic and extrinsic metallic and oxidic contributions to the spectra. It was shown that, in addition to the metallic contribution from the substrate and the oxidic contribution from stoichiometric ZrO2, two additional suboxidic components are contained in the measured Zr3d spectra of the oxidized Zr metal. As evidenced by angle-resolved XPS and in situ ellipsometry, both of these components can be attributed to a gradient of Zr enrichment in the region of the oxide film adjacent to the metal/oxide interface (with the highest Zr enrichment at the metal/oxide interface). Investigation of the oxide-film growth kinetics at various pO2, as determined independently using both techniques, showed the occurrence of an initial regime of very fast, electric-field-controlled growth, followed by a much slower oxidation stage. As a result, an, on average, nonstoichiometric oxide film develops. The observed effect of the pO2 on the low-temperature oxidation of Zr has been discussed in terms of the relationship between the fraction of coverage of the surface with physi- and chemisorbed oxygen and the applied pO2.

  13. Effect of Sodium Nitrate and Nitrate Reducing Bacteria on In vitro Methane Production and Fermentation with Buffalo Rumen Liquor

    PubMed Central

    Sakthivel, Pillanatham Civalingam; Kamra, Devki Nandan; Agarwal, Neeta; Chaudhary, Lal Chandra

    2012-01-01

    Nitrate can serve as a terminal electron acceptor in place of carbon dioxide and inhibit methane emission in the rumen and nitrate reducing bacteria might help enhance the reduction of nitrate/nitrite, which depends on the type of feed offered to animals. In this study the effects of three levels of sodium nitrate (0, 5, 10 mM) on fermentation of three diets varying in their wheat straw to concentrate ratio (700:300, low concentrate, LC; 500:500, medium concentrate, MC and 300:700, high concentrate, HC diet) were investigated in vitro using buffalo rumen liquor as inoculum. Nitrate reducing bacteria, isolated from the rumen of buffalo were tested as a probiotic to study if it could help in enhancing methane inhibition in vitro. Inclusion of sodium nitrate at 5 or 10 mM reduced (p<0.01) methane production (9.56, 7.93 vs. 21.76 ml/g DM; 12.20, 10.42 vs. 25.76 ml/g DM; 15.49, 12.33 vs. 26.86 ml/g DM) in LC, MC and HC diets, respectively. Inclusion of nitrate at both 5 and 10 mM also reduced (p<0.01) gas production in all the diets, but in vitro true digestibility (IVTD) of feed reduced (p<0.05) only in LC and MC diets. In the medium at 10 mM sodium nitrate level, there was 0.76 to 1.18 mM of residual nitrate and nitrite (p<0.01) also accumulated. In an attempt to eliminate residual nitrate and nitrite in the medium, the nitrate reducing bacteria were isolated from buffalo adapted to nitrate feeding and introduced individually (3 ml containing 1.2 to 2.3×106 cfu/ml) into in vitro incubations containing the MC diet with 10 mM sodium nitrate. Addition of live culture of NRBB 57 resulted in complete removal of nitrate and nitrite from the medium with a further reduction in methane and no effect on IVTD compared to the control treatments containing nitrate with autoclaved cultures or nitrate without any culture. The data revealed that nitrate reducing bacteria can be used as probiotic to prevent the accumulation of nitrite when sodium nitrate is used to reduce in vitro methane emissions. PMID:25049631

  14. Sulfate and nitrate collected by filter sampling near the tropopause

    NASA Technical Reports Server (NTRS)

    Humenik, F. M.; Lezberg, E. A.; Otterson, D. A.

    1980-01-01

    Filter samples collected near the tropopause with an F-106 aircraft and two Boeing 747 aircraft were analyzed for sulfate and nitrate ion content. Within the range of routine commercial flight altitudes (at or below 12.5 km), stratospheric mass mixing ratios for the winter-spring group averaged 0.26 ppbm for sulfate and 0.35 ppbm for nitrate. For the summer-fall group, stratosphere mixing ratios averaged 0.13 ppbm and 0.25 ppbm for sulfate and nitrate, respectively. Winter-spring group tropospheric mass mixing ratios averaged 0.08 ppbm for sulfate and 0.10 ppbm for nitrate, while summer-fall group tropospheric mixing ratios averaged 0.05 ppbm for sulfate and 0.08 ppbm for nitrate. Correlations of the filter data with available ozone data suggest that the sulfate and nitrate are transported from the stratosphere to the troposphere.

  15. Sustainability of natural attenuation of nitrate in agricultural aquifers

    USGS Publications Warehouse

    Green, Christopher T.; Bekins, Barbara A.

    2010-01-01

    Increased concentrations of nitrate in groundwater in agricultural areas, coinciding with increased use of chemical and organic fertilizers, have raised concern because of risks to environmental and human health. At some sites, these problems are mitigated by natural attenuation of nitrate as a result of microbially mediated reactions. Results from U.S. Geological Survey (USGS) research under the National Water-Quality Assessment (NAWQA) program show that reactions of dissolved nitrate with solid aquifer minerals and organic carbon help lower nitrate concentrations in groundwater beneath agricultural fields. However, increased fluxes of nitrate cause ongoing depletion of the finite pool of solid reactants. Consumption of the solid reactants diminishes the capacity of the aquifer to remove nitrate, calling into question the long-term sustainability of these natural attenuation processes.

  16. Evaluating Ecosystem Services for Reducing Groundwater Nitrate Contamination: Nitrate Attenuation in the Unsaturated and Saturated Zones

    NASA Astrophysics Data System (ADS)

    Wang, J.

    2013-12-01

    Nitrates are the most common type of groundwater contamination in agricultural regions. Environmental policies targeting nitrates have focused on input control (e.g., restricted fertilizer application), intermediate loads control (e.g., reduce nitrate leached from crop fields), and final loads control (e.g., reduce catchment nitrate loads). Nitrate loads can be affected by hydrological processes in both unsaturated and saturated zones. Although many of these processes have been extensively investigated in literature, they are commonly modeled as exogenous to farm management. A couple of recent studies by scientists from the Lawrence Livermore National Laboratory show that in some situations nitrate attenuation processes in the unsaturated/saturated zone, particularly denitrification, can be intensified by certain management practices to mitigate nitrate loads. Therefore, these nitrate attenuation processes can be regarded as a set of ecosystem services that farmers can take advantage of to reduce their cost of complying with environmental policies. In this paper, a representative California dairy farm is used as a case study to show how such ecosystem attenuation services can be framed within the farm owner's decision-making framework as an option for reducing groundwater nitrate contamination. I develop an integrated dynamic model, where the farmer maximizes discounted net farm profit over multiple periods subject to environmental regulations. The model consists of three submodels: animal-waste-crop, hydrologic, and economic model. In addition to common choice variables such as irrigation, fertilization, and waste disposal options, the farmer can also endogenously choose from three water sources: surface water, deep groundwater (old groundwater in the deep aquifer that is not affected by farm effluent in the short term), and shallow groundwater (drainage water that can be recycled via capture wells at the downstream end of the farm). The capture wells not only recycle wastewater, but can also increase the likelihood of denitrification. Thus the farmer essentially can choose whether, and to which extent, to install capture wells and take advantage of the ecosystem attenuation services. Decision rules from the dynamic optimization model demonstrate best management practices for the farm to improve its economic and environmental performance. I further use an economic valuation technique to value these services. Under the Millennium Ecosystem Assessment framework, nitrate attenuation in the unsaturated and saturated zone provides regulatory ecosystem services to humans, mainly nutrient regulation and waste treatment. With the integrated farm model, the production function approach is adopted to get the economic value of these regulatory services. The results highlight the significant role the environment can play in nitrate pollution control and potential benefits from designing policies that acknowledge this role. The most desirable policies are those that create incentive for farmers to use potential ecosystem services, which significantly reduce environmental compliance costs and increase social welfare.

  17. Electrochemical cell having an alkali-metal-nitrate electrode

    SciTech Connect

    Roche, M.F.; Preto, S.K.

    1982-06-04

    A power-producing secondary electrochemical cell includes a molten alkali metal as the negative-electrode material and a molten-nitrate salt as the positive-electrode material. The molten material in the respective electrodes are separated by a solid barrier of alkali-metal-ion conducting material. A typical cell includes active materials of molten sodium separated from molten sodium nitrate and other nitrates in mixture by a layer of sodium ..beta..'' alumina.

  18. Evaluation of nitrate reductase activity in Rhizobium japonicum

    SciTech Connect

    Streeter, J.G.; DeVine, P.J.

    1983-08-01

    Nitrate reductase activity was evaluated by four approaches, using four strains of Rhizobium japonicum and 11 chlorate-resistant mutants of the four strains. It was concluded that in vitro assays with bacteria or bacteroids provide the most simple and reliable assessment of the presence or absence of nitrate reductase. Nitrite reductase activity with methyl viologen and dithionite was found, but the enzyme activity does not confound the assay of nitrate reductase. 18 references

  19. Nitrate Paradigm Does Not Hold Up for Sugarcane

    PubMed Central

    Robinson, Nicole; Brackin, Richard; Vinall, Kerry; Soper, Fiona; Holst, Jirko; Gamage, Harshi; Paungfoo-Lonhienne, Chanyarat; Rennenberg, Heinz; Lakshmanan, Prakash; Schmidt, Susanne

    2011-01-01

    Modern agriculture is based on the notion that nitrate is the main source of nitrogen (N) for crops, but nitrate is also the most mobile form of N and easily lost from soil. Efficient acquisition of nitrate by crops is therefore a prerequisite for avoiding off-site N pollution. Sugarcane is considered the most suitable tropical crop for biofuel production, but surprisingly high N fertilizer applications in main producer countries raise doubt about the sustainability of production and are at odds with a carbon-based crop. Examining reasons for the inefficient use of N fertilizer, we hypothesized that sugarcane resembles other giant tropical grasses which inhibit the production of nitrate in soil and differ from related grain crops with a confirmed ability to use nitrate. The results of our study support the hypothesis that N-replete sugarcane and ancestral species in the Andropogoneae supertribe strongly prefer ammonium over nitrate. Sugarcane differs from grain crops, sorghum and maize, which acquired both N sources equally well, while giant grass, Erianthus, displayed an intermediate ability to use nitrate. We conclude that discrimination against nitrate and a low capacity to store nitrate in shoots prevents commercial sugarcane varieties from taking advantage of the high nitrate concentrations in fertilized soils in the first three months of the growing season, leaving nitrate vulnerable to loss. Our study addresses a major caveat of sugarcane production and affords a strong basis for improvement through breeding cultivars with enhanced capacity to use nitrate as well as through agronomic measures that reduce nitrification in soil. PMID:21552564

  20. Method for making fine and ultrafine spherical particles of zirconium titanate and other mixed metal oxide systems

    DOEpatents

    Hu, Michael Z.

    2006-05-23

    Disclosed is a method for making amorphous spherical particles of zirconium titanate and crystalline spherical particles of zirconium titanate comprising the steps of mixing an aqueous solution of zirconium salt and an aqueous solution of titanium salt into a mixed solution having equal moles of zirconium and titanium and having a total salt concentration in the range from 0.01 M to about 0.5 M. A stearic dispersant and an organic solvent is added to the mixed salt solution, subjecting the zirconium salt and the titanium salt in the mixed solution to a coprecipitation reaction forming a solution containing amorphous spherical particles of zirconium titanate wherein the volume ratio of the organic solvent to aqueous part is in the range from 1 to 5. The solution of amorphous spherical particles is incubated in an oven at a temperature .ltoreq.100.degree. C. for a period of time .ltoreq.24 hours converting the amorphous particles to fine or ultrafine crystalline spherical particles of zirconium titanate.

  1. Nitrate Leaching from Intensive Fiber Production on Abandoned Agricultural Land

    SciTech Connect

    Williams, T.M.

    1999-01-01

    Paper outlines nitrate leaching results of loblolly pine and sweet gum that were grown with irrigation, continuous fertilization and insect pest control on a year old abandoned peanut field. Wells and tension lysimeters were used to measure nitrate in soil moisture and groundwater on three replicate transects for two years. Groundwater nitrate concentration beneath the minimum treatment was much higher than the maximum treatment and old field. All three treatments often exceeded the drinking water standard. Forest and lake edge had low levels while the soil moisture nitrate concentrations in the two plantation treatments were much higher than the old field.

  2. Who is drinking nitrate in their well water?

    SciTech Connect

    Mitchell, T.J.; Harding, A.K.

    1996-10-01

    This study evaluated the health risks for a rural northeastern Oregon population which is exposed to high nitrate levels in well water. The study also identified possible sources of nitrate contamination, and investigated measures the resident had taken to reduce their nitrate exposure from well water. Three data sets were used in the study, including a telephone survey of the residents, existing information collected by the Oregon Department of Environmental Quality about well water nitrate concentrations, and demographic information from census records. Results revealed that 23% of the surveyed population was drinking well water that contained nitrate in excess of the 10 ppm nitrate-nitrogen maximum contaminant level adopted by the US Environmental Protection Agency for drinking water. Seventy-two percent of the households with nitrate levels exceeding the 10 ppm level did not use devices that effectively remove nitrates. The population included few women of childbearing age, and was generally older than other nearby urban or rural populations. Resident infants were not exposed to well water nitrate in excess of the 10 ppm level, and were therefore not at apparent risk for methemoglobinemia (blue-baby syndrome). Although the risk of infant methemoglobinemia was low in this area, it is recommended that alternative water sources be explored, and that follow-up monitoring be performed by state and/or local agencies.

  3. Endogenously Nitrated Proteins in Mouse Brain: Links To Neurodegenerative Disease

    SciTech Connect

    Sacksteder, Colette A.; Qian, Weijun; Knyushko, Tanya V.; Wang, Haixing H.; Chin, Mark H.; Lacan, Goran; Melega, William P.; Camp, David G.; Smith, Richard D.; Smith, Desmond J.; Squier, Thomas C.; Bigelow, Diana J.

    2006-07-04

    Increased nitrotyrosine modification of proteins has been documented in multiple pathologies in a variety of tissue types; emerging evidence suggests its additional role in redox regulation of normal metabolism. In order to identify proteins sensitive to nitrating conditions in vivo, a comprehensive proteomic dataset identifying 7,792 proteins from whole mouse brain, generated by LC/LC-MS/MS analyses, was used to identify nitrated proteins. This analysis resulted in identification of 31 unique nitrotyrosine sites within 29 different proteins. Over half of the nitrated proteins identified have been reported to be involved in Parkinson's disease, Alzheimer's disease, or other neurodegenerative disorders. Similarly, nitrotyrosine immunoblots of whole brain homogenates show that treatment of mice with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), an experimental model of Parkinson's disease, induces increased nitration of the same protein bands observed to be nitrated in brains of untreated animals. Comparing sequences and available high resolution structures around nitrated tyrosines with those of unmodified sites indicates a preference of nitration in vivo for surface accessible tyrosines in loops, characteristics consistent with peroxynitrite-induced tyrosine modification. More striking is the five-fold greater nitration of tyrosines having nearby basic sidechains, suggesting electrostatic attraction of basic groups with the negative charge of peroxynitrite. Together, these results suggest that elevated peroxynitrite generation plays a role in neurodegenerative changes in the brain and provides a predictive tool of functionally important sites of nitration.

  4. Aluminum nitrate recrystallization and recovery from liquid extraction raffinates

    SciTech Connect

    Griffith, W.L.; Compere, A.L.; Googin, J.M.; Huxtable, W.P.

    1991-09-01

    The solid sludges resulting form biodenitrification of discarded aluminum nitrate are the largest Y-12 Plant process solid waste. Aluminum nitrate feedstocks also represent a major plant materials cost. The chemical constraints on aluminum nitrate recycle were investigated to determine the feasibility of increasing recycle while maintaining acceptable aluminum nitrate purity. Reported phase behavior of analogous systems, together with bench research, indicated that it would be possible to raise the recycle rate from 35% to between 70 and 90% by successive concentration and recrystallization of the mother liquor. A full scale pilot test successfully confirmed the ability to obtain 70% recycle in existing process equipment.

  5. Electrospun cellulose nitrate and polycaprolactone blended nanofibers

    NASA Astrophysics Data System (ADS)

    Nartker, Steven; Hassan, Mohamed; Stogsdill, Michael

    2015-03-01

    Pure cellulose nitrate (CN) and blends of CN and polycaprolactone were electrospun to form nonwoven mats. Polymers were dissolved in a mixed solvent system of tetrahydrofuran and N,N-dimethylformamide. The concentrations were varied to obtain sub-micron and nanoscale fiber mats. Fiber mats were analyzed using scanning electron microscopy, contact angle analysis, Fourier transform infrared spectroscopy and thermal gravimetric analysis. The fiber morphology, surface chemistry and contact angle data show that these electrospun materials are suitable for applications including biosensing, biomedical and tissue engineering.

  6. Possibilities of surface coating for thermal insulation. [zirconium dioxide, titanium dioxide, and zircon coatings

    NASA Technical Reports Server (NTRS)

    Poeschel, E.; Weisser, G.

    1979-01-01

    Calculations performed for pulsating heat sources indicate a relatively thin (200-1000 micron) coating can lower temperature both inside and on the surface of a construction material. Various coating materials (including zirconium dioxide) are discussed, together with possible thermic stresses and ways to deal with the latter.

  7. Nanocrystals Embedded Zirconium-doped Hafnium Oxide High-k Gate Dielectric Films 

    E-print Network

    Lin, Chen-Han

    2012-10-19

    Nanocrystals embedded zirconium-doped hafnium oxide (ZrHfO) high-k gate dielectric films have been studied for the applications of the future metal oxide semiconductor field effect transistor (MOSFET) and nonvolatile memory. ZrHfO has excellent gate...

  8. Zirconium-doped tantalum oxide high-k gate dielectric films 

    E-print Network

    Tewg, Jun-Yen

    2005-02-17

    A new high-k dielectric material, i.e., zirconium-doped tantalum oxide (Zr-doped TaOx), in the form of a sputter-deposited thin film with a thickness range of 5-100 nm, has been studied. Important applications of this new ...

  9. Extraction of zirconium(IV) from aqueous acid solutions by trioctylphosphine oxide

    SciTech Connect

    Sato, T.

    1983-01-01

    The extraction of zirconium(IV) from aqueous solutions of hydrochloric, nitric and sulphuric acids by trioctylphosphine oxide (TOPO) in kerosene has been investigated under different conditions. The organic phases have been studied by infrared and nuclear magnetic resonance spectroscopies. The extraction equilibria are discussed in light of the results obtained. 7 figures, 2 tables.

  10. Journal of Crystal Growth 307 (2007) 302308 Equilibrium analysis of zirconium carbide CVD growth

    E-print Network

    Anderson, Timothy J.

    2007-01-01

    -like electrical conduc- tivity (2 Â 104 /O cm), high hardness (25,000 N/mm2 ), high melting temperature (3400 1CJournal of Crystal Growth 307 (2007) 302­308 Equilibrium analysis of zirconium carbide CVD growth equilibrium study was performed to investigate the effect of growth parameters on the constitution in Zr

  11. Analysis of titanium and zirconium in red mud with energy dispersive x-ray spectrometry

    SciTech Connect

    Kobya, M.; Ertugrul, M.; Dogan, O.; Simsek, O.

    1996-11-01

    An energy dispersive x-ray fluorescence technique was used for the determination of Titanium (Ti) and Zirconium (Zr) in red mud by using a standard addition method. An annular {sup 241}Am source is employed for excitation of K shells of elements. 13 refs., 2 figs., 1 tab.

  12. 40 CFR 471.90 - Applicability; description of the zirconium-hafnium forming subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Applicability; description of the zirconium-hafnium forming subcategory. 471.90 Section 471.90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS NONFERROUS METALS FORMING AND METAL...

  13. 40 CFR 471.90 - Applicability; description of the zirconium-hafnium forming subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Applicability; description of the zirconium-hafnium forming subcategory. 471.90 Section 471.90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS NONFERROUS METALS FORMING AND METAL...

  14. 40 CFR 471.90 - Applicability; description of the zirconium-hafnium forming subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 31 2012-07-01 2012-07-01 false Applicability; description of the zirconium-hafnium forming subcategory. 471.90 Section 471.90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) NONFERROUS METALS FORMING AND METAL POWDERS POINT SOURCE...

  15. Structure of zirconium alloy oxides formed in pure water studied with synchrotron radiation and

    E-print Network

    Motta, Arthur T.

    Structure of zirconium alloy oxides formed in pure water studied with synchrotron radiation schemes for achieving optimum corrosion response. It is now well established that corrosion resistance.elsevier.com/locate/jnucmat Journal of Nuclear Materials 324 (2004) 6­22 #12;contrast, small SPP size (less than one-tenth micron

  16. Impacts of drainage water management on subsurface drain flow, nitrate concentration, and nitrate loads in Indiana

    EPA Science Inventory

    Drainage water management is a conservation practice that has the potential to reduce drainage outflow and nitrate (NO3) loss from agricultural fields while maintaining or improving crop yields. The goal of this study was to quantify the impact of drainage water management on dra...

  17. Immobilization of nitrate reductase onto epoxy affixed silver nanoparticles for determination of soil nitrates.

    PubMed

    Sachdeva, Veena; Hooda, Vinita

    2015-08-01

    Epoxy glued silver nanoparticles were used as immobilization support for nitrate reductase (NR). The resulting epoxy/AgNPs/NR conjugates were characterized at successive stages of fabrication by scanning electron microscopy and fourier transform infrared spectroscopy. The immobilized enzyme system exhibited reasonably high conjugation yield (37.6±0.01 ?g/cm(2)), with 93.54±0.88% retention of specific activity. Most favorable working conditions of pH, temperature and substrate concentration were ascertained to optimize the performance of epoxy/AgNPs/NR conjugates for soil nitrate quantification. The analytical results for soil nitrate determination were consistent, reliable and reproducible. Minimum detection limit of the method was 0.05 mM with linearity from 0.1 to 11.0 mM. The % recoveries of added nitrates (0.1 and 0.2 mM) were<95.0% and within-day and between-day coefficients of variations were 0.556% and 1.63% respectively. The method showed good correlation (R(2)=0.998) with the popular Griess reaction method. Epoxy/AgNPs bound NR had a half-life of 18 days at 4 °C and retained 50% activity after 15 reuses. PMID:25957718

  18. Sources of aerosol nitrate to the Gulf of Aqaba: Evidence from 15 O of nitrate

    E-print Network

    Paytan, Adina

    N and 18 O) of water soluble aerosol nitrate was measured in aerosol samples collected in Eilat isotopes Oxygen isotopes Atmospheric particulates The nitrogen (N) and oxygen (O) isotopic composition (15 a substantial contributor of low 15 N nitrogen to the oligotrophic waters of the Gulf of Aqaba. Thus, while

  19. Developmental stage-specific and nitrate-independent regulation of nitrate reductase gene expression in rapeseed.

    PubMed Central

    Fukuoka, H; Ogawa, T; Minami, H; Yano, H; Ohkawa, Y

    1996-01-01

    cDNA clones for two isogenes of nitrate reductase (NR) have been isolated from rapeseed (Brassica napus L.) androgenetic haploid embryos induced by microspore culture. NR mRNA accumulation can be detected by northern hybridization at 14 d after culture initiation when embryos develop to the heart/torpedo-shaped stage. Whole-mount in situ hybridization experiments demonstrate that the mRNA accumulation is developmental stage specific. In addition, even when cultured in media containing no nitrate, embryos accumulated NR mRNA to almost the same level as the control. This indicates the unique regulation of NR in embryogenesis in which NR mRNA transcription is activated in a developmental stage-specific manner that is independent of nitrate induction. In zygotic embryogenesis, a stage-specific accumulation of NR mRNA was also observed. By contrast, the obvious effect of nitrate on NR expression that has been reported in many plant species was also confirmed in rapeseed leaf. Quantitative combined reverse transcription-polymerase chain reaction analysis suggests that the flexible and variable regulation of NR expression, which is organ specific, nitrogen metabolite specific, and developmental stage specific, is caused principally by regulation of one major structural gene. PMID:8685274

  20. PRODUCTION OF ORGANIC NITRATES FROM HYDROXYL AND NITRATE RADICAL REACTION WITH PROPYLENE

    EPA Science Inventory

    Measurements of the gas-phase production rates of alpha-nitratoacetone, propylene glycol dinitrate, 2-hydroxy propyl nitrate, and 2-nitrato propyl alcohol (2-NPA) in a C3H6/N2O5/air dark reaction and a C3H6/NOX/air irradiation are reported. The probable operative reaction mechani...

  1. The effect of zirconium-based surface treatment on the cathodic disbonding resistance of epoxy coated mild steel

    NASA Astrophysics Data System (ADS)

    Ghanbari, A.; Attar, M. M.

    2014-10-01

    The effect of zirconium-based surface treatment on the cathodic disbonding resistance and adhesion performance of an epoxy coated mild steel substrate was investigated. The obtained data from pull-off, cathodic disbonding test and electrochemical impedance spectroscopy (EIS) indicated that the zirconium conversion layer significantly improved the adhesion strength and cathodic disbonding resistance of the epoxy coating. This may be attributed to formation of some polar zirconium compounds on the surface and increment of surface roughness, that were evident in the results of field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM), respectively.

  2. Construction and characterization of nitrate reductase-based amperometric electrode and nitrate assay of fertilizers and drinking water.

    PubMed

    Glazier, S A; Campbell, E R; Campbell, W H

    1998-04-15

    The construction and characterization of a nitrate reductase-based amperometric electrode for determination of nitrate ion is described. The electrode consisted of nitrate reductase held by dialysis membrane onto a Nafion-coated glassy carbon electrode. Methyl viologen was allowed to absorb into the Nafion layer, which acted as a reservoir for the electron mediator. The utility of the electrode to assay fertilizer and water sample for nitrate was demonstrated. The assays conducted with this electrode compared well with colorimetric and potentiometric assays of the same samples. PMID:9569760

  3. Effect of Four Methods of Surface Treatment on Shear Bond Strength of Orthodontic Brackets to Zirconium

    PubMed Central

    Yassaei, Soghra; Aghili, Hossein Agha; Davari, Abdolrahim

    2015-01-01

    Objectives: Providing reliable attachment between bracket base and zirconia surface is a prerequisite for exertion of orthodontic force. The purpose of the present study was to evaluate the effect of four zirconium surface treatment methods on shear bond strength (SBS) of orthodontic brackets. Materials and Methods: One block of zirconium was trimmed into four zirconium surfaces, which served as our four study groups and each had 18 metal brackets bonded to them. Once the glazed layer was removed, the first group was etched with 9.6% hydrofluoric acid (HF), and the remaining three groups were prepared by means of sandblasting and 1W, and 2W Er: YAG laser, respectively. After application of silane, central incisor brackets were bonded to the zirconium surfaces. The SBS values were measured by a Dartec testing machine with a crosshead speed of 1 mm/min. Data were analyzed using one-way ANOVA and Tukey’s HSD for multiple comparisons. Results: The highest SBS was achieved in the sandblasted group (7.81±1.02 MPa) followed in a descending order by 2W laser group (6.95±0.87 MPa), 1W laser group (6.87±0.92 MPa) and HF acid etched group (5.84±0.78 MPa). The differences between the study groups were statistically significant except between the laser groups (P<0.05). Conclusion: In terms of higher bond strength and safety, sandblasting and Er: YAG laser irradiation with power output of 1W and 2W can be considered more appropriate alternatives to HF acid etching for zirconium surface treatment prior to bracket bonding. PMID:26622283

  4. Composition and microstructure of zirconium and hafnium germanates obtained by different chemical routes

    SciTech Connect

    Utkin, A.V. Prokip, V.E.; Baklanova, N.I.

    2014-01-15

    The phase composition and morphology of zirconium and hafnium germanates synthesized by ceramic and co-precipitation routes were studied. The products were characterized using high-temperature X-ray diffraction analysis (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and thermal (TG/DTA) analysis. To investigate the phase composition and stoichiometry of compounds the unit cell parameters were refined by full-profile Rietveld XRD analysis. The morphology of products and its evolution during high-temperature treatment was examined by SEM analysis. It was stated that there is the strong dependence of the phase composition and morphology of products on the preparation route. The ceramic route requires a multi-stage high-temperature treatment to obtain zirconium and hafnium germanates of 95% purity or more. Also, there are strong diffusion limitations to obtain hafnium germanate Hf{sub 3}GeO{sub 8} by ceramic route. On the contrary, the co-precipitation route leads to the formation of nanocrystalline single phase germanates of stoichiometric composition at a relatively low temperatures (less than 1000 °C). The results of quantitative XRD analysis showed the hafnium germanates are stoichiometric compounds in contrast to zirconium germanates that form a set of solid solutions. This distinction may be related to the difference in the ion radii of Zr and Hf. - Graphical abstract: The phase composition and morphology of zirconium and hafnium germanates synthesized by ceramic and co-precipitation routes were studied. It was stated that there is the strong dependence of the phase composition and morphology of products on the preparation route. Display Omitted - Highlights: • Zr and Hf germanates were synthesized by ceramic and co-precipitation routes. • The morphology of products depends on the synthesis parameters. • Zirconium germanates forms a set of solid solutions. • Hafnium germanates are stoichiometric compounds.

  5. Preparation of zirconia coatings by hydrolysis of zirconium alkoxide with hydrogen peroxide

    SciTech Connect

    Sakurai, Chihiro; Fukui, Toshimi; Okuyama, Masahiko )

    1993-04-01

    Zirconia has gained a great deal of attention because of its superior properties of mechanical strength, chemical resistance, and ionic conductivity. Zirconia coatings and thin films are receiving attention as tribological and thermal barrier coatings for engines, high-reflective coatings, solid electrolytes for fuel cells, oxygen sensors, etc. The sol-gel coating method has several advantages, such as low processing temperatures, homogeneity, control of micro-structure, and good productivity compared to chemical vapor deposition and physical vapor deposition. However, there are few reports concerning the preparation of zirconia coatings and thin films by the sol-gel method. Up to the present, zirconia coatings have been prepared from zirconium propoxide (not heated), zirconium tetrabutoxide modified by acetylacetone and ethyl acetoacetate, zirconium diethoxydichloride (ZrCl[sub 2](OC[sub 2]H[sub 5])[sub 2]), and a hydrosol prepared from a zirconium oxychloride solution. Coatings of 8.8-mol%-yttria-doped zirconia were fabricated using a transparent and spinnable sol prepared by hydrolysis of zirconium alkoxide with hydrogen peroxide and nitric acid. The sol gave a crack-free coating film consisting of fine grains. The crystalline phase was cubic after heating of 1,000 and 1,200 C and cubic and tetragonal at 1,350 C, with the coating being highly oriented in the (111) plane, especially at 1,000 C. Activation energy of the coating films was higher than that of the bulk. Transmittance through a film thickness of about 0.3 [mu]m on each side was 75%.

  6. Further in vitro studies with oxiconazole nitrate.

    PubMed

    Shadomy, S; Wang, H; Shadomy, H J

    1988-04-01

    Oxiconazole nitrate was compared in vitro with ketoconazole and econazole nitrate in tests with 96 dermatophytes, 18 isolates of Malassezia furfur, and seven isolates of Exophiala werneckii. An agar dilution procedure was used employing either Kimmig's agar or Sabouraud's dextrose agar supplemented with Olive oil and Tween 80. Econazole was the more active compound in tests with Microsporum species (41 isolates) and most isolates of Trichophyton species (45 isolates). Oxiconazole was the more active compound in tests with T. tonsurans and T. rubrum. However, differences between results for oxiconazole and econazole and the dermatophytes were only marginal. Ketoconazole was the most active compound in tests with M. furfur; some cross resistance on the part of several isolates of M. furfur between oxiconazole and econazole was noted. All three compounds were active against E. werneckii with MIC90 values of either 0.25 or 0.5 microgram/ml. Epidermophyton floccosum was the most susceptible of all organisms tested with all MIC values for all three drugs being less than or equal to 0.063 microgram/ml, the lowest concentration tested. PMID:3180708

  7. Electrochemical processing of nitrate waste solutions

    SciTech Connect

    Not Available

    1990-10-12

    Nitrate and nitrite have been almost completely removed from the synthetic effluent steam with good efficiency by affecting a separation across a pair of ion exchange membranes. In addition to recovering acid and base in this process, the volume of the remaining effluent is reduced considerably by transport of water across the membrane. One of the problems that remains with this process, however, is the stability of the membranes and particularly the stability of the anion exchange membrane. This membrane is exposed to both nitric acid and strongly alkaline solutions in the cell and to date long term stability has been a problem with the membranes tested. It is recommended that further work should evaluate other newly available membranes as well as study the effects of radiation on the performance of the membranes. The direct reduction of nitrate and nitrite has been studied at several different electrode materials and it has been demonstrated that cathode material has a large effect on both the efficiency and the gas product distribution. Highest current efficiencies for the reduction process are seen at those electrode materials that are known to show high hydrogen overpotentials. Flow cell studies have demonstrated that temperature and current density are also important parameters in the system. The reduction process has been run efficiently at high current densities (600 mAcm{sup {minus}2}) at 80{degrees}C at a lead cathode.

  8. Electrochemical processing of nitrate waste solutions

    SciTech Connect

    Genders, D.; Weinberg, N.; Hartsough, D. )

    1992-10-07

    The second phase of research performed at The Electrosynthesis Co., Inc. has demonstrated the successful removal of nitrite and nitrate from a synthetic effluent stream via a direct electrochemical reduction at a cathode. It was shown that direct reduction occurs at good current efficiencies in 1,000 hour studies. The membrane separation process is not readily achievable for the removal of nitrites and nitrates due to poor current efficiencies and membrane stability problems. A direct reduction process was studied at various cathode materials in a flow cell using the complete synthetic mix. Lead was found to be the cathode material of choice, displaying good current efficiencies and stability in short and long term tests under conditions of high temperature and high current density. Several anode materials were studied in both undivided and divided cell configurations. A divided cell configuration was preferable because it would prevent re-oxidation of nitrite by the anode. The technical objective of eliminating electrode fouling and solids formation was achieved although anode materials which had demonstrated good stability in short term divided cell tests corroded in 1,000 hour experiments. The cause for corrosion is thought to be F[sup [minus

  9. Crystallization of sodium nitrate from radioactive waste

    SciTech Connect

    Krapukhin, V.B.; Krasavina, E.P. Pikaev, A.K.

    1997-07-01

    From the 1940s to the 1980s, the Institute of Physical Chemistry of the Russian Academy of Sciences (IPC/RAS) conducted research and development on processes to separate acetate and nitrate salts and acetic acid from radioactive wastes by crystallization. The research objective was to decrease waste volumes and produce the separated decontaminated materials for recycle. This report presents an account of the IPC/RAS experience in this field. Details on operating conditions, waste and product compositions, decontamination factors, and process equipment are described. The research and development was generally related to the management of intermediate-level radioactive wastes. The waste solutions resulted from recovery and processing of uranium, plutonium, and other products from irradiated nuclear fuel, neutralization of nuclear process solutions after extractant recovery, regeneration of process nitric acid, equipment decontamination, and other radiochemical processes. Waste components include nitric acid, metal nitrate and acetate salts, organic impurities, and surfactants. Waste management operations generally consist of two stages: volume reduction and processing of the concentrates for storage, solidification, and disposal. Filtration, coprecipitation, coagulation, evaporation, and sorption were used to reduce waste volume. 28 figs., 40 tabs.

  10. Safety Testing of Ammonium Nitrate Based Mixtures

    NASA Astrophysics Data System (ADS)

    Phillips, Jason; Lappo, Karmen; Phelan, James; Peterson, Nathan; Gilbert, Don

    2013-06-01

    Ammonium nitrate (AN)/ammonium nitrate based explosives have a lengthy documented history of use by adversaries in acts of terror. While historical research has been conducted on AN-based explosive mixtures, it has primarily focused on detonation performance while varying the oxygen balance between the oxidizer and fuel components. Similarly, historical safety data on these materials is often lacking in pertinent details such as specific fuel type, particle size parameters, oxidizer form, etc. A variety of AN-based fuel-oxidizer mixtures were tested for small-scale sensitivity in preparation for large-scale testing. Current efforts focus on maintaining a zero oxygen-balance (a stoichiometric ratio for active chemical participants) while varying factors such as charge geometry, oxidizer form, particle size, and inert diluent ratios. Small-scale safety testing was conducted on various mixtures and fuels. It was found that ESD sensitivity is significantly affected by particle size, while this is less so for impact and friction. Thermal testing is in progress to evaluate hazards that may be experienced during large-scale testing.

  11. 76 FR 23569 - Termination of the Suspension Agreement on Solid Fertilizer Grade Ammonium Nitrate From the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-27

    ...of the Russian Federation (``Russia'') dated February 22, 2011, that...nitrate (``ammonium nitrate'') from Russia were being, or were likely to be, sold...See Certain Ammonium Nitrate from Russia, Investigation No....

  12. 40 CFR 415.530 - Applicability; description of the silver nitrate production subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...true Applicability; description of the silver nitrate production subcategory. 415...CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Silver Nitrate Production Subcategory § 415.530 Applicability; description of the silver nitrate production subcategory....

  13. 40 CFR 415.530 - Applicability; description of the silver nitrate production subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...false Applicability; description of the silver nitrate production subcategory. 415...CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Silver Nitrate Production Subcategory § 415.530 Applicability; description of the silver nitrate production subcategory....

  14. 40 CFR 415.530 - Applicability; description of the silver nitrate production subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...true Applicability; description of the silver nitrate production subcategory. 415...CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Silver Nitrate Production Subcategory § 415.530 Applicability; description of the silver nitrate production subcategory....

  15. 40 CFR 415.530 - Applicability; description of the silver nitrate production subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...true Applicability; description of the silver nitrate production subcategory. 415...CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Silver Nitrate Production Subcategory § 415.530 Applicability; description of the silver nitrate production subcategory....

  16. 40 CFR 415.530 - Applicability; description of the silver nitrate production subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...true Applicability; description of the silver nitrate production subcategory. 415...CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Silver Nitrate Production Subcategory § 415.530 Applicability; description of the silver nitrate production subcategory....

  17. Effects of arsenic on nitrate metabolism in arsenic hyperaccumulating and non-hyperaccumulating ferns

    E-print Network

    Ma, Lena

    Effects of arsenic on nitrate metabolism in arsenic hyperaccumulating and non Arsenic reduced the activity of nitrate and nitrite reductase more in Pteris ensiformis than Pteris March 2009 Accepted 26 March 2009 Keywords: Arsenic Nitrate metabolism Pteris vittata Arsenic

  18. Diversity of Assimilatory Nitrate Reductase Genes From Plankton and Epiphytes Associated with a Seagrass Bed

    E-print Network

    Ward, Bess

    Microbial Ecology Diversity of Assimilatory Nitrate Reductase Genes From Plankton and Epiphytes 2006 / Online publication: 13 September 2007 Abstract Assimilatory nitrate reductase gene fragments, Florida, USA. Nitrate reductase genes from diatoms (NR) and heterotrophic bacteria (nasA) were amplified

  19. 46 CFR 153.560 - Special requirements for Alkyl (C7-C9) nitrates.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Special requirements for Alkyl (C7-C9) nitrates. 153.560 Section 153.560 Shipping...Special requirements for Alkyl (C7-C9) nitrates. (a) The carriage temperature of octyl nitrates must be maintained below 100 °C...

  20. 46 CFR 153.560 - Special requirements for Alkyl (C7-C9) nitrates.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Special requirements for Alkyl (C7-C9) nitrates. 153.560 Section 153.560 Shipping...Special requirements for Alkyl (C7-C9) nitrates. (a) The carriage temperature of octyl nitrates must be maintained below 100 °C...

  1. 46 CFR 153.560 - Special requirements for Alkyl (C7-C9) nitrates.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Special requirements for Alkyl (C7-C9) nitrates. 153.560 Section 153.560 Shipping...Special requirements for Alkyl (C7-C9) nitrates. (a) The carriage temperature of octyl nitrates must be maintained below 100 °C...

  2. 46 CFR 153.560 - Special requirements for Alkyl (C7-C9) nitrates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Special requirements for Alkyl (C7-C9) nitrates. 153.560 Section 153.560 Shipping...Special requirements for Alkyl (C7-C9) nitrates. (a) The carriage temperature of octyl nitrates must be maintained below 100 °C...

  3. 40 CFR 418.40 - Applicability; description of the ammonium nitrate subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Applicability; description of the ammonium nitrate subcategory. 418.40 Section...MANUFACTURING POINT SOURCE CATEGORY Ammonium Nitrate Subcategory § 418.40 Applicability; description of the ammonium nitrate subcategory. The provisions...

  4. Relationships between DOC bioavailability and nitrate removal in an upland stream: An experimental

    E-print Network

    Relationships between DOC bioavailability and nitrate removal in an upland stream: An experimental, Denitrification, Dissolved organic carbon, Nitrate, Stream sediments Abstract. The Catskill Mountains States. Some streams draining Catskill catchments have shown dramatic increases in nitrate concentrations

  5. 46 CFR 153.560 - Special requirements for Alkyl (C7-C9) nitrates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Special requirements for Alkyl (C7-C9) nitrates. 153.560 Section 153.560 Shipping...Special requirements for Alkyl (C7-C9) nitrates. (a) The carriage temperature of octyl nitrates must be maintained below 100 °C...

  6. 40 CFR 418.40 - Applicability; description of the ammonium nitrate subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Applicability; description of the ammonium nitrate subcategory. 418.40 Section...MANUFACTURING POINT SOURCE CATEGORY Ammonium Nitrate Subcategory § 418.40 Applicability; description of the ammonium nitrate subcategory. The provisions...

  7. Strontium sorption and precipitation behaviour during bioreduction in nitrate impacted sediments

    E-print Network

    Burke, Ian

    Strontium sorption and precipitation behaviour during bioreduction in nitrate impacted sediments Available online 9 March 2012 Editor: J. Fein Keywords: Strontium Bioreduction Incorporation Sorption Nitrate Nuclear The behaviour of strontium (Sr2+ ) during microbial reduction in nitrate impacted

  8. 48. U.S. NITRATE PLANT UNDER CONSTRUCTION, VIEW LOOKING N.E. AT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    48. U.S. NITRATE PLANT UNDER CONSTRUCTION, VIEW LOOKING N.E. AT THE AMMONIUM NITRATE BUILDING UNDER CONSTRUCTION, AUGUST 24, 1918. - United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Muscle Shoals, Colbert County, AL

  9. Method for improved decomposition of metal nitrate solutions

    DOEpatents

    Haas, P.A.; Stines, W.B.

    1981-01-21

    A method for co-conversion of aqueous solutions of one or more heavy metal nitrates is described, wherein thermal decomposition within a temperature range of about 300 to 800/sup 0/C is carried out in the presence of about 50 to 500% molar concentration of ammonium nitrate to total metal.

  10. Distribution and sources of nitrate-nitrogen in Kansas groundwater.

    PubMed

    Townsend, M A; Macko, S A; Young, D P

    2001-11-01

    Kansas is primarily an agricultural state. Irrigation water and fertilizer use data show long- term increasing trends. Similarly, nitrate-N concentrations in groundwater show long-term increases and exceed the drinking-water standard of 10 mg/l in many areas. A statistical analysis of nitrate-N data collected for local and regional studies in Kansas from 1990 to 1998 (747 samples) found significant relationships between nitrate-N concentration with depth, age, and geographic location of wells. Sources of nitrate-N have been identified for 297 water samples by using nitrogen stable isotopes. Of these samples, 48% showed fertilizer sources (+2 to +8) and 34% showed either animal waste sources (+10 to +15 with nitrate-N greater than 10 mg/l) or indication that enrichment processes had occurred (+10 or above with variable nitrate-N) or both. Ultimate sources for nitrate include nonpoint sources associated with past farming and fertilization practices, and point sources such as animal feed lots, septic systems, and commercial fertilizer storage units. Detection of nitrate from various sources in aquifers of different depths in geographically varied areas of the state indicates that nonpoint and point sources currently impact and will continue to impact groundwater under current land uses. PMID:12805791

  11. 46 CFR 148.227 - Calcium nitrate fertilizers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Calcium nitrate fertilizers. 148.227 Section 148.227 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES CARRIAGE OF BULK SOLID... fertilizers. This part does not apply to commercial grades of calcium nitrate fertilizers consisting mainly...

  12. 46 CFR 148.227 - Calcium nitrate fertilizers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Calcium nitrate fertilizers. 148.227 Section 148.227 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES CARRIAGE OF BULK SOLID... fertilizers. This part does not apply to commercial grades of calcium nitrate fertilizers consisting mainly...

  13. 46 CFR 148.227 - Calcium nitrate fertilizers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Calcium nitrate fertilizers. 148.227 Section 148.227 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES CARRIAGE OF BULK SOLID... fertilizers. This part does not apply to commercial grades of calcium nitrate fertilizers consisting mainly...

  14. 46 CFR 148.227 - Calcium nitrate fertilizers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Calcium nitrate fertilizers. 148.227 Section 148.227 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES CARRIAGE OF BULK SOLID... fertilizers. This part does not apply to commercial grades of calcium nitrate fertilizers consisting mainly...

  15. Comment on "A Reservoir of Nitrate Beneath Desert Soils"

    E-print Network

    Jackson, Robert B.

    Comment on "A Reservoir of Nitrate Beneath Desert Soils" Walvoord et al. (1) reported a large nitrate pool located deep ( 1 m) beneath desert soils. Two aspects of this work were particularly vary greatly over short temporal and spatial scales. We re- cently investigated 16 desert soil profiles

  16. DENITRIFICATION-BASED REMOVAL OF NITRATE FROM SUBSURFACE DRAINAGE WATER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrate in subsurface (tile) drainage from corn and soybean fields is an important source of contributing to excessive stream nitrate concentrations. Field and laboratory studies assessed the performance of wood chips as a carbon source for a denitrification wall. Drainage lines in the center of t...

  17. Biological Remediation of Groundwater Containing both Nitrate and Atrazine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to its high usage, mobility and recalcitrant nature, atrazine is a common groundwater contaminant. Moreover, groundwaters that are contaminated with atrazine often contain nitrate as well. Nitrate interferes with the biological degradation of atrazine and makes it more difficult to use in-sit...

  18. GROUNDWATER NITRATE REMOVAL CAPACITY OF RIPARIAN ZONES IN

    E-print Network

    Gold, Art

    GROUNDWATER NITRATE REMOVAL CAPACITY OF RIPARIAN ZONES IN URBANIZING WATERSHEDS BY TARA KIMBERLY the watershed, however, is not well understood. Nitrate in groundwater moving through the "biologically active and geomorphology of riparian zones, potentially changing riparian groundwater denitrification capacity. Little work

  19. Cu(II) - Catalyzed Hydrazine Reduction of Ferrous Nitrate

    SciTech Connect

    Karraker, D.G.

    2001-10-15

    This report discusses the results of a study of catalyzed hydrazine reduction of ferrous nitrate. It is apparent that there is a substantial reaction between hydrazine and nitrate ion (or nitric acid) to produce HN3 during both the reduction of Fe(III) and during storage at room temperature.

  20. THE MASS ACCOMMODATION COEFFICIENT OF AMMONIUM NITRATE AEROSOL. (R823514)

    EPA Science Inventory

    The mass transfer rate of pure ammonium nitrate between the aerosol and gas phases was
    quantified experimentally by the use of the tandem differential mobility analyzer/scanning mobility
    particle sizer (TDMA/SMPS) technique. Ammonium nitrate particles 80-220 nm in diameter<...

  1. Crystal Structure of a Nitrate/Nitrite Exchanger

    PubMed Central

    Zheng, Hongjin; Wisedchaisri, Goragot; Gonen, Tamir

    2013-01-01

    Summary Mineral nitrogen in nature is often found in the form of nitrate (NO3-). Numerous microorganisms evolved to assimilate nitrate and use it as a major source of mineral nitrogen uptake1. Nitrate, which is central in nitrogen metabolism, is first reduced to nitrite (NO2-) through a two-electron reduction reaction2,3. The accumulation of cellular nitrite can be harmful because nitrite can be reduced to the cytotoxic nitric oxide. Instead, nitrite is rapidly removed from the cell by channels and transporters, or reduced to ammonium or dinitrogen through the action of assimilatory enzymes3. Despite decades of effort no structure is currently available for any nitrate transport protein and the mechanism by which nitrate is transported remains largely obscure. Here we report the structure of a bacterial nitrate/nitrite transport protein, NarK, from Escherichia coli, with and without substrate. The structures reveal a positively charged substrate-translocation pathway lacking protonatable residues, suggesting that NarK functions as a nitrate/nitrite exchanger and that H+s are unlikely to be co-transported. Conserved arginine residues form the substrate-binding pocket, which is formed by association of helices from the two halves of NarK. Key residues that are important for substrate recognition and transport are identified and related to extensive mutagenesis and functional studies. We propose that NarK exchanges nitrate for nitrite by a rocker-switch mechanism facilitated by inter-domain H-bond networks. PMID:23665960

  2. Role of Nitrate in Conditioning Aquifer Sediments for Technetium

    E-print Network

    Burke, Ian

    Role of Nitrate in Conditioning Aquifer Sediments for Technetium Bioreduction G A R E T H T . W . L of technetium-99 in sediment microcosm experiments with varying nitrate and carbonate concentrations addedH "conditioning" step. Introduction Technetium-99 is a radioactive fission product formed in nuclear reactors

  3. Nitrate Water Activities, Science Study Aid No. 4.

    ERIC Educational Resources Information Center

    Agricultural Research Service (USDA), Washington, DC.

    Intended to supplement a regular program, this pamphlet provides background information, related activities, and suggestions for other activities on the subject of nitrate as a water pollutant. Two activities related to plant nutrient pollution, nitrate filtration and measuring mitrate used by plants, are explained in detail, outlining objectives,…

  4. New graphite nitrate derived intercalation compounds of higher thermal stability

    NASA Astrophysics Data System (ADS)

    Savoskin, M. V.; Yaroshenko, A. P.; Whyman, G. E.; Mysyk, R. D.

    2006-05-01

    The instability of graphite nitrate is a main issue as to its extensive industrial use. Novel graphite nitrate compounds of higher stability were produced via cointercalation of carboxylic acids, ethers, esters and nitriles. Structural transformations on cointercalation and effect of hydrogen bonding on stabilization are discussed.

  5. 40 CFR 721.7500 - Nitrate polyether polyol (generic name).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Nitrate polyether polyol (generic name). 721.7500 Section 721.7500 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC... Substances § 721.7500 Nitrate polyether polyol (generic name). (a) Chemical substance and significant...

  6. Method for improved decomposition of metal nitrate solutions

    DOEpatents

    Haas, Paul A. (Knoxville, TN); Stines, William B. (Knoxville, TN)

    1983-10-11

    A method for co-conversion of aqueous solutions of one or more heavy metal nitrates wherein thermal decomposition within a temperature range of about 300.degree. to 800.degree. C. is carried out in the presence of about 50 to 500% molar concentration of ammonium nitrate to total metal.

  7. Evaporation of Ammonium Nitrate Aerosol in a Heated Nephelometer

    E-print Network

    Evaporation of Ammonium Nitrate Aerosol in a Heated Nephelometer: Implications for Field scattering coefficient of ammonium nitrate aerosol due to evaporation in a heated nephelometer. Changes in the aerosol scattering coefficient due to evaporation agree with measurements to within 10%. Application

  8. The effect of sulfur and zirconium Co-doping on the oxidation of NiCrAl

    NASA Technical Reports Server (NTRS)

    Smialek, James L.

    1987-01-01

    The adhesion behavior of Al2O3 scales formed on NiCrAl+Zr alloys was examined as a function of both sulfur and zirconium doping levels. In general, very high levels of zirconium were required to counteract the detrimental effects of sulfur. A sulfur-zirconium adherence map was constructed, as determined from the oxidation and spalling behavior in 1100 C cyclic tests. For low sulfur alloys, the amount of zirconium required for adherence at any given sulfur level can be described by Zr greater than 600 S sup 0.2 (in ppma). These results underscore the importance of sulfur to adhesion mechanisms and suggests that sulfur gettering is a first order effect of reactive element additions to MCrAl alloys.

  9. Characterization of Alpha-Phase Sintering of Uranium and Uranium-Zirconium Alloys for Advanced Nuclear Fuel Applications 

    E-print Network

    Helmreich, Grant

    2012-02-14

    /dehydriding process. The size distribution and morphology of the uranium powder produced by this method were determined by digital optical microscopy. Once the characteristics of the source uranium powder were known, uranium and uranium-zirconium pellets were pressed...

  10. Thermal analysis of uranium zirconium hydride fuel using a lead-bismuth gap at LWR operating temperatures

    E-print Network

    Ensor, Brendan M. (Brendan Melvin)

    2012-01-01

    Next generation nuclear technology calls for more advanced fuels to maximize the effectiveness of new designs. A fuel currently being studied for use in advanced light water reactors (LWRs) is uranium zirconium hydride ...

  11. Synthesis and structural characterisation using Rietveld and pair distribution function analysis of layered mixed titanium-zirconium phosphates

    NASA Astrophysics Data System (ADS)

    Burnell, Victoria A.; Readman, Jennifer E.; Tang, Chiu C.; Parker, Julia E.; Thompson, Stephen P.; Hriljac, Joseph A.

    2010-09-01

    Crystalline metal (IV) phosphates with variable zirconium-to-titanium molar ratios of general formula (Ti 1- xZr x)(HPO 4) 2·H 2O have been prepared by precipitation of soluble salts of the metals with phosphoric acid and heating the amorphous solids in 12 M H 3PO 4 in an autoclave. The new materials are structurally characterised by Rietveld analysis of synchrotron X-ray powder diffraction data and pair distribution function (PDF) analysis of high energy synchrotron X-ray total scattering data. A broad range of zirconium-titanium phosphate solid solutions were formed showing isomorphous substitution of titanium by zirconium in the ?-titanium phosphate lattice and vice versa for titanium substitution into the ?-zirconium phosphate lattice. In both cases the solubility is partial with the coexistence of two substituted phases observed in samples with nominal compositions between the solubility limits.

  12. Transcriptional networks in the nitrate response of Arabidopsis thaliana.

    PubMed

    Vidal, Elena A; Álvarez, José M; Moyano, Tomás C; Gutiérrez, Rodrigo A

    2015-10-01

    Nitrogen is an essential macronutrient for plants and its availability is a key determinant of plant growth and development and crop yield. Besides their nutritional role, N nutrients and metabolites are signals that activate signaling pathways that modulate many plant processes. Because the most abundant inorganic N source for plants in agronomic soils is nitrate, much of the work to understand plant N-signaling has focused on this nutrient. Over the last years, several studies defined a comprehensive catalog of nitrate-responsive genes, involved in nitrate transport, metabolism and a variety of other processes. Despite significant progress in recent years, primarily using Arabidopsis thaliana as a model system, the molecular mechanisms by which nitrate elicits changes in transcript abundance are still not fully understood. Here we highlight recent advancements in identifying key transcription factors and transcriptional mechanisms that orchestrate the gene expression response to changes in nitrate availability in A. thaliana. PMID:26247122

  13. Is Nitrate Anion Photodissociation Mediated by Singlet-Triplet Absorption?

    PubMed

    Svoboda, Ond?ej; Slaví?ek, Petr

    2014-06-01

    Photolysis of the nitrate anion is involved in the oxidation processes in the hydrosphere, cryosphere, and stratosphere. While it is known that the nitrate photolysis in the long-wavelength region proceeds with a very low quantum yield, the mechanism of the photodissociation remains elusive. Here, we present the quantitative modeling of singlet-singlet and singlet-triplet absorption spectra in the atmospherically relevant region around 300 nm, and we argue that a spin-forbidden transition between the singlet ground state and the first triplet state contributes non-negligibly to the nitrate anion photolysis. We further propose that the nitrate anion excited into the first singlet excited state relaxes nonradiatively into its ground state. The full understanding of the nitrate anion photolysis can improve modeling of the asymmetric solvation in the atmospheric processes, e.g., photolysis on the surfaces of ice or snow. PMID:26273880

  14. Electrochemical processing of alkaline nitrate and nitrite wastes

    SciTech Connect

    Hobbs, D T; Ebra, M A

    1986-01-01

    Processing of high-level waste at the Savannah River Plant (SRP) will produce, as a by-product, a low-level, alkaline salt solution containing approximately 17% sodium nitrate and sodium nitrite. This solution will be incorporated into a cement formulation, saltstone, and placed in an engineered landfill. Electrochemical methods have been investigated to decrease the nitrate and nitrite in this solution in order to lower the leaching of nitrate and nitrite from saltstone and to reduce the volume of saltstone. Laboratory experiments have demonstrated the technical feasibility of electrolytically reducing the nitrate and nitrite in a synthetic salt solution similar in composition to that expected to be produced at SRP. Greater than 99% of the sodium nitrate and sodium nitrite can be reduced, producing ammonia, nitrogen, oxygen, and sodium hydroxide. In addition, significant reductions in the volume of saltstone may be realized if the sodium hydroxide produced by electrolysis can be recycled.

  15. Nitrate behavior in ground waters of the southeastern USA

    USGS Publications Warehouse

    Nolan, B.T.

    1999-01-01

    Principal components analysis (PCA) was performed with water-quality data from studies conducted during 1993 to 1995 to explore potential nitrate- attenuation processes in ground waters of the southeastern USA. Nitrate reduction is an important attenuation process in selected areas of the Southeast. A nitrate-reduction component explains 23% of the total variance in the data and indicates that nitrate and dissolved oxygen (DO) are inversely related to ammonium, iron, manganese, and dissolved organic carbon (DOC). Additional components extracted by PCA include calcite dissolution (18% of variance explained) and phosphate dissolution (9% of variance explained). Reducing conditions in ground waters of the region influence nitrate behavior through bacterially mediated reduction in the presence of organic matter, and by inhibition of nitrate formation in anoxic ground water beneath forested areas. Component scores are consistent with observed water- quality conditions in the region. For example, median nitrate concentration in ground-water samples from the Albemarle-Pamlico Drainage Basin (ALBE) Coastal Plain is <0.05 mg L-1, median DOC concentration is 4.2 mg L-1, and median DO concentration is 2.1 mg L-1, consistent with denitrification. Nitrate reduction does not occur uniformly throughout the Southeast. Median DO concentrations in ground-water samples from the Apalachicola- Chattahoochee-Flint River Basin (ACFB) are 6.2 to 7.1 mg L-1, and median nitrate concentrations are 0.61 to 2.2 mg L-1, inconsistent with denitrification. Similarly, median DO concentration in samples from the Georgia-Florida Coastal Plain (GAFL) is 6.0 mg L-1 and median nitrate concentration is 5.8 mg L-1.

  16. Removal of p-aminophenol and p-nitrophenol from aqueous solution through adsorption on antimony, cadmium, and zirconium ferrocyanides.

    PubMed

    Tewari, Brij Bhushan; Boodhoo, Marc

    2005-09-15

    Adsorptive interaction of p-aminophenol and p-nitrophenol in the concentration range 10(-4)-10(-5) M and at room temperature (30+/-1 degrees C) was studied with antimony, cadmium, and zirconium ferrocyanides. The interaction followed the Langmuir type of adsorption in general. The p-nitrophenol was found to have greater affinity for the antimony, cadmium, and zirconium ferrocyanides then the p-aminophenol. PMID:15935363

  17. REMOVAL OF ADDED NITRATE IN COTTON BURR COMPOST, MULCH COMPOST, AND PEAT: MECHANISMS AND POTENTIAL USE FOR GROUNDWATER NITRATE REMEDIATION

    EPA Science Inventory

    We conducted batch tests on the nature and kinetics of removal of added nitrate in cotton burr compost, mulch compost, and sphagnum peat that may be potentially used in a permeable reactive barrier (PRB) for groundwater nitrate remediation. A rigorous steam autoclaving protocol (...

  18. NITRATE REMOVAL FROM CONTAMINATED WATER SUPPLIES. VOLUME 1. DESIGN AND INITIAL PERFORMANCE OF A NITRATE REMOVAL PLANT

    EPA Science Inventory

    The report reviews the design, construction, and operation of a 1-mgd nitrate removal plant in McFarland, CA. The plant treats well water for domestic use. Nitrates are reduced from approximately 15.8 mg NO3-N/L to well below the maximum contaminant level of 10 mg NO3-N/L. Contin...

  19. Indirect determination of nitric oxide production by reduction of nitrate with a freeze-thawing-resistant nitrate reductase from Escherichia coli MC1061.

    PubMed

    Arias-Negrete, Sergio; Jiménez-Romero, Luis A; Solís-Martínez, Martha O; Ramírez-Emiliano, Joel; Avila, Eva E; Cuéllar-Mata, Patricia

    2004-05-01

    Preparation of a nitrate reductase lysate of Escherichia coli MC1061 to measure nitrate and nitrite in biologic fluids is described. To obtain the crude bacterial lysate containing nitrate reductase activity, E. coli MC1061 was subjected to 16-20 freeze-thawing cycles, from -70 to 60 degrees C, until nitrite reductase activity was < or = 25%. Nitrate reductase activity was detected mainly in the crude preparation. To validate the nitrate reduction procedure, standard nitrate solutions (1.6-100 microM) were incubated with the nitrate reductase preparation for 3 h at 37 degrees C, and nitrite was estimated by the Griess reaction in a microassay. Nitrate solutions were reduced to nitrite in a range of 60-70%. Importantly, no cofactors were necessary to perform nitrate reduction. The biological samples were first reduced with the nitrate reductase preparation. After centrifugation, samples were deproteinized with either methanol/ether or zinc sulfate and nitrite was quantified. The utility of the nitrate reductase preparation was assessed by nitrate+nitrite determination in serum of animals infected with the protozoan Entamoeba histolytica or the bacteria E. coli and in the supernatant of cultured lipopolysaccharide-stimulated RAW 264.7 mouse macrophages. Our results indicate that the nitrate reductase-containing lysate provides a convenient tool for the reduction of nitrate to determine nitrate+nitrite in biological fluids by spectrophotometric methods. PMID:15081902

  20. Rovibronic Variational Calculations of the Nitrate Radical

    NASA Astrophysics Data System (ADS)

    Changala, Bryan; Baraban, Joshua H.; Stanton, John F.

    2015-06-01

    In recent years, sophisticated diabatic Hamiltonians have been developed in order to understand the low-energy vibronic level structure of the nitrate radical (NO_3), which exhibits strong coupling between the ~X and doubly degenerate ~B states. Previous studies have reproduced the observed vibronic level positions up to 2000 wn~above the zero-point level, yet the rotational structure has remained uninvestigated with ab initio methods. In this talk, we present calculations of the N?0 rovibronic structure of low-lying vibronic states of NO_3, in which complicated rovibrational and Coriolis interactions have been observed. Our results include calculations using both adiabatic and diabatic Hamiltonians, enabling a direct comparison between the two. We discuss extensions of our treatment to include spin-orbit and spin-rotation effects.