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. Zirconium and zirconium alloy ingots for nuclear application

    SciTech Connect

    Not Available

    1980-01-01

    This specification covers vacuum arc-melted zirconium and zirconium alloy ingots for nuclear application. Four grades, designated as reactor grade zirconium R60001, zirconium-tin alloys R60802 and R60804, and zirconium-niobium alloy R60901, suitable for nuclear application are described.

  3. Manage corrosion with zirconium

    SciTech Connect

    Yau, T.L.; Bird, K.W.

    1995-01-01

    Zirconium has been used to construct process equipment for over three decades. Zirconium offers low maintenance costs, high reliability, and strong environmental protection with several other advantages: (1) it resists attack by strong acids and caustics, as well as by many salt solutions and molten salts; (2) zirconium has adequate strength for process equipment operating at elevated temperatures; (3) it is relatively low in density, high in thermal conductivity, and low in the coefficient of thermal expansion; (4) zirconium can be fabricated into almost any shape by conventional methods; (5) it is nontoxic and biocompatible; and (6) zirconium does not produce colored ions. The paper looks at some of the major applications of zirconium to better understand its use. The corrosives cited include acetic, formic, nitric, sulfuric, and lactic acids, and phenolic resins.

  4. Nitrate Protocol

    NSDL National Science Digital Library

    The GLOBE Program, UCAR (University Corporation for Atmospheric Research)

    2003-08-01

    The purpose of this resource is to measure the nitrate-nitrogen of water. Students will use a nitrate kit to measure the nitrate-nitrogen in the water at their hydrology site. The exact procedure depends on the instructions in the nitrate kit used.

  5. ZIRCONIUM AND HAFNIUM--2000 87.1 ZIRCONIUM AND HAFNIUM

    E-print Network

    with mantles of zirconium, lanthanum and yttrium oxides. By 1900, the zirconium oxide mantle mixture had been came into use which used rods or "glowers" made of 25 percent yttrium oxide and 75 percent zirconium baddeleyite, a natural form of zirconium oxide or zirconia (ZrO2), is a distant second to zircon in its

  6. Zirconium and zirconium alloy ingots for nuclear application

    SciTech Connect

    Not Available

    1981-01-01

    The specification covers vacuum arc-melted zirconium and zirconium alloy ingots for nuclear application. Four grades, designated as reactor grade zirconium R60001, zirconium-tin alloys R60802 and R60804, and zirconium-niobium alloy R60901, suitable for nuclear application are described. The specification includes ordering information, manufacture, conditioning, chemical requirements, hardness, ultrasonic test, numerical limits, inspection, certification, packaging, and marking. (JMT)

  7. Organic derivatives of zirconium phosphate 

    E-print Network

    Fine, Steven Beryl

    1980-01-01

    of y and u- zirconium phosphate 4 A plot of the interlayer spacing versus the number of moles of propylene oxide reactive in y-zirconium 2-hydroxyl-1-propyl phosphate. 5 The proposed interlayer structure of y-zirconium 1-phenyl phosphate, . 6 A... of hydration. Amines can be inter- calated into zirconium phosphate, spreading the layers apart. The success of amine intercalation lead researchers to believe that zirconium phosphate might react with other organic compounds. Because ethylene oxide, 1, 2...

  8. Laser ablated zirconium plasma: A source of neutral zirconium

    SciTech Connect

    Yadav, Dheerendra; Thareja, Raj K. [Department of Physics, Indian Institute of Technology Kanpur, Kanpur-208016, Uttar Pradesh (India)

    2010-10-15

    The authors report spectroscopic investigations of laser produced zirconium (Zr) plasma at moderate laser fluence. At low laser fluence the neutral zirconium species are observed to dominate over the higher species of zirconium. Laser induced fluorescence technique is used to study the velocity distribution of ground state neutral zirconium species. Two-dimensional time-resolved density distributions of ground state zirconium is mapped using planner laser induced fluorescence imaging and total ablated mass of neutral zirconium atoms is estimated. Temporal and spatial evolutions of electron density and temperature are discussed by measuring Stark broadened profile and ratio of intensity of emission lines, respectively.

  9. Colorimetric determination of zirconium with 1-(2-pyridylazo)-2-naphthol.

    PubMed

    Ross, L E; Drabek, V M; Larsen, R P

    1969-06-01

    A method is described for the determination of as little as 50 ppm of zirconium in uranium-fission element alloys and zinc magnesium-uranium-fission element alloys. Zirconium is extracted from a nitric acid-aluminium nitrate medium with dibutyl phosphate in toluene. The uranium co-extracted with the zirconium is removed by scrubbing with hydrochloric acid-ammonium thiocyanate solution. A portion of the organic phase is mixed with pyridine-toluene solution of 1-(2-pyridylazo)-2-naphthol to develop the colour. PMID:18960573

  10. ZIRCONIUM AND HAFNIUM--2001 86.1 ZIRCONIUM AND HAFNIUM

    E-print Network

    minerals. The principal economic source of zirconium is the zirconium silicate mineral zircon (ZrSiO4 to zircon in its economic significance. Zircon is the primary source of all hafnium. Zirconium and hafnium are contained in zircon at a ratio of about 50:1. Zircon is a coproduct or byproduct of the mining

  11. Zirconium in sulfuric acid applications

    SciTech Connect

    Webster, R.T.; Yau, T.L.

    1986-02-01

    Zirconium is one of the few metals that resists attack by sulfuric acid at concentrations up to 75% and temperatures to boiling and above. This capability makes zirconium a good structural metal for use in 40 to 65% H/sub 2/SO/sub 4/ up to boiling temperatures and for weak acid concentrations at elevated temperatures. Zirconium's corrosion properties in sulfuric acid solutions are compared with nickel base alloys. Examples of applications and limitations in the use of zirconium are presented.

  12. 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.

  13. Superstoichiometric hydride of zirconium

    SciTech Connect

    Kupryazhkin, A.Ya.; Shchepetkin, A.A.; Zabolotskaya, E.V.; Pletnev, R.N.; Alyamovskii, S.I.; Kitaev, G.A.

    1987-12-01

    Superstoichiometric hydrides of zirconium have been obtained all the way up to the composition ZrH/sub 2.4/ by additional hydrogenation of ZrH/sub 2/ as a result of redistribution of hydrogen atoms between t- and o-positions. In the preparation of the hydrides the authors used zirconium iodide with an impurity content no greater than 10/sup -2/ to 10/sup -2/ mole %; the hydrogen and helium used in this work had a minimum purity of 99.95%. The content of hydrogen in the specimens was determined by a volumetric method. The x-ray diffraction analysis was performed in a DRON-2.0 unit (CuK/sub ..cap alpha../ radiation). PMR spectra were recorded in a broad-line spectrometer in the temperature interval 150-450 K.

  14. Polarization behavior of growing zirconia films in a fused salt medium and its relation to the oxidation of zirconium and its alloys

    Microsoft Academic Search

    Ramasubramanian

    1975-01-01

    Platinum is a reliable reference electrode for potential measurements during the corrosion and electrochemical polarization studies on zirconium alloys in a fused nitrate and nitrite or nitrate medium; these potentials correspond closely to the potential drops across the oxide layer. The oxidation rates calculated from the oxidation currents derived from the analysis of the polarization curves are in good agreement

  15. ZIRCONIUM AND HAFNIUM--1998 86.1 ZIRCONIUM AND HAFNIUM

    E-print Network

    is the zirconium silicate mineral, zircon (ZrSiO4). The mineral baddeleyite, a natural form of zirconia (ZrO2), is secondary to zircon in its economic significance. Zircon is the primary source of all hafnium. Zirconium and hafnium are contained in zircon at a ratio of about 50 to 1. Zircon is a coproduct or byproduct

  16. ZIRCONIUM AND HAFNIUM--1999 86.1 ZIRCONIUM AND HAFNIUM

    E-print Network

    is the zirconium silicate mineral, zircon (ZrSiO4). The mineral baddeleyite, a natural form of zirconia (ZrO2), is secondary to zircon in its economic significance. Zircon is the primary source of all hafnium. Zirconium and hafnium are contained in zircon at a ratio of about 50 to 1. Zircon is a coproduct or byproduct

  17. ZIRCONIUM AND HAFNIUM By Joseph Gambogi

    E-print Network

    in the Earth's ofzircon, zirconium oxide, or other zirconium chemicals. The crust; however zircon (zirconium of commercial significance. Zirconium and containing alloys. hafnium are both contained in zircon at a ratio of about 50:1. The mineral zircon is used for facings on foundry molds. Zircon is a byproduct of the mining

  18. The alloy system uranium-titanium-zirconium

    Microsoft Academic Search

    B. Howlett

    1959-01-01

    The uranium-titanium-zirconium system in the composition range to 40 ; at.% titanium, 70 at.% zirconium is reported in nine isothermal sections between ; 575 deg and 1000 deg C. The principal features of the alloys are discussed. ; (auth);

  19. Hafnium Nitrate Precursor Synthesis and HfO 2 Thin Film Deposition

    Microsoft Academic Search

    Weiwei Zhuang; John F. Conley; Yoshi Ono; David R. Evans; R. Solanki

    2002-01-01

    The paper will introduce a simple new method for the synthesis of both hafnium and zirconium nitrate precursors. The intermediate product, dinitrogen pentoxide produced from the extraction of water from fuming nitric acid via phosphorus pentoxide, was condensed with a liquid nitrogen trap into a flask containing either hafnium or zironium tetrachloride. To achieve a high yield, the mixture of

  20. Zirconium and hafnium in meteorites

    NASA Technical Reports Server (NTRS)

    Ehmann, W. D.; Chyi, L. L.

    1974-01-01

    The abundances of zirconium and hafnium have been determined in nine stony meteorites by a new, precise neutron-activation technique. The Zr/Hf abundance ratios for the chondrites vary in a rather narrow range, consistent with previously published observations from our group. Replicate analyses of new, carefully selected clean interior samples of the Cl chondrite Orgueil yield mean zirconium and hafnium abundances of 5.2 and 0.10 ppm, respectively. These abundances are lower than we reported earlier for two Cl chondrite samples which we now suspect may have suffered contamination. The new Cl zirconium and hafnium abundances are in closer agreement with predictions based on theories of nucleosynthesis than the earlier data.

  1. 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.

  2. Zirconium alloy heat treatment process

    Microsoft Academic Search

    Urquhart

    1982-01-01

    Zirconium-base alloy channels, fuel cladding tubes, and other nuclear reactor structural components having unique resistance to accelerated pustular corrosion in a boiling water reactor environment are produced by a sequence of heat treatments causing segregation of intermetallic particulate precipitate phase in two dimensional arrays of particles of diameter from 100 to 400 angstroms located along grain boundaries and sub-grain boundaries

  3. 40 CFR 721.10250 - Zirconium lysine complex (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Zirconium lysine complex (generic). 721...Chemical Substances § 721.10250 Zirconium lysine complex (generic). (a...chemical substance identified generically as zirconium lysine complex (PMN...

  4. 40 CFR 721.9973 - Zirconium dichlorides (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Zirconium dichlorides (generic). 721.9973...Chemical Substances § 721.9973 Zirconium dichlorides (generic). (a) Chemical...chemical substances identified generically as zirconium dichlorides (PMNs...

  5. 40 CFR 721.9973 - Zirconium dichlorides (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Zirconium dichlorides (generic). 721.9973...Chemical Substances § 721.9973 Zirconium dichlorides (generic). (a) Chemical...chemical substances identified generically as zirconium dichlorides (PMNs...

  6. 40 CFR 721.10250 - Zirconium lysine complex (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Zirconium lysine complex (generic). 721...Chemical Substances § 721.10250 Zirconium lysine complex (generic). (a...chemical substance identified generically as zirconium lysine complex (PMN...

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

    E-print Network

    Walljet Electrochemistry: Quantifying Molecular Transport through Metallopolymeric and Zirconium precision for the two methods. We apply this technique to a system consisting of zirconium phosphonate supramolecular square building blocks (Keefe; et al. Adv. Mater. 2003, 15, 1936). The zirconium phosphate

  8. 40 CFR 721.9973 - Zirconium dichlorides (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Zirconium dichlorides (generic). 721.9973...Chemical Substances § 721.9973 Zirconium dichlorides (generic). (a) Chemical...chemical substances identified generically as zirconium dichlorides (PMNs...

  9. 40 CFR 721.10708 - Zirconium substituted heteropolycyclic (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Zirconium substituted heteropolycyclic (generic...Chemical Substances § 721.10708 Zirconium substituted heteropolycyclic (generic...chemical substance identified generically as zirconium substituted heteropolycyclic...

  10. 40 CFR 721.10250 - Zirconium lysine complex (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Zirconium lysine complex (generic). 721...Chemical Substances § 721.10250 Zirconium lysine complex (generic). (a...chemical substance identified generically as zirconium lysine complex (PMN...

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

    E-print Network

    Mechanism for zirconium oxide atomic layer deposition using bis,,methylcyclopentadienyl...methoxymethyl zirconium J. W. Elama and M. J. Pellin Argonne National Laboratory, Argonne, Illinois 60439, USA S. D; accepted 22 November 2007; published online 20 December 2007 The mechanism for zirconium oxide atomic layer

  12. Applications for Zirconium and Columbium Alloys

    NASA Astrophysics Data System (ADS)

    Condliff, Alex F.

    1986-09-01

    Currently, zirconium and columbium are used in a wide range of applications, overlapping only in the field of corrosion control. As a construction material, zirconium is primarily used by the nuclear power industry. The use of zirconium in the chemical processing industry (CPI) is, however, increasing steadily. Columbium alloys are primarily applied as superconducting alloys for research particle accelerators and fusion generators as well as in magnetic resonance imaging for medical diagnosis.

  13. 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.

  14. Process for producing zirconium based granules

    SciTech Connect

    Jade, S.S.

    1990-05-22

    This patent describes a process for the production f amorphous zirconium based granules. It comprises: adding about 2--15 wt % of a suitable phase stabilizer to an aqueous solutio, based upon the total weight of ZrO{sub 2} in solution, to produce an aqueous solution having a pH in the range of about 4 to 7 comprising a zirconium based complex and phase stabilizer and thereafter; drying the aqueous solution comprising the zirconium based complex and the phase stabilizer at a temperature below about 180{degrees} C. for a time sufficient to evaporate the aqueous solution thereby forming amorphous zirconium based granules containing the phase stabilizer.

  15. Zirconium in the nuclear industry

    SciTech Connect

    Franklin, D.G.; Adamson, R.B.

    1984-01-01

    This book examines the properties of Zircaloy-2, Zircaloy-4, and Zr-2.5Nb with regard to their use as structural materials in nuclear reactors. Topics considered include refinement and fabrication (extractive metallurgy, zirconium and hafnium separation, electron-beam remelting, pressure tube development, cold working and heat treatments), basic metallurgical studies (etching, strain anisotropy, fuel cladding, anneal hardening, recrystallization, hydrides in zirconium alloy tubes), texture and irradiation creep (microstructure, ultrasonic velocity, in-reactor creep, fuel rods, deformation), irradiation growth (proton and neutron bombardment, high-fluence irradiation growth), corrosion (ZrO/sub 2/ films, aqueous corrosion kinetics, corrosive effects of lithium hydroxide, oxidation films, hydridation), fracture studies (stress-corrosion cracking, hydrogen cracking), and high-temperature and transient effects (cladding deformation in LOCA, high-temperature behavior of fuel rods, steam oxidation kinetics, dissolution of solid UO/sub 2/ by molten Zircaloy-4).

  16. 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.

  17. Development of zirconium alloys. Part II

    Microsoft Academic Search

    A. D. Schwope; W. Chubb

    1952-01-01

    A number of alloys of zirconium have been investigated as part of a program aimed at improving the high-temperature tensile and creep strength of zirconium. These alloys include aluminum, beryllium, lead, magnesium, molybdenum, niobium, tantalum, tin, titanium, tungsten, vanadium, and zinc, binary and ternary alloys. The data indicate that aluminum, lead, molybdenum niobium, tin, titanium, tungsten, and vanadium can be

  18. DISSOLUTION OF ZIRCONIUM IN HCl-METHANOL

    Microsoft Academic Search

    J. R. Aylward; E. M. Whitener

    1962-01-01

    The dissolution of zirconium in HCl-methanol was studied ; potentiostatically as a function of HCl concentration and temperature. At low ; overvoltages the reaction is activation controlled and the rate independent of ; HCl concentration. In this region preferential grain boundary attack results in ; etching and separation from the electrode of flnely divided panticles of alpha -; zirconium. At

  19. 2006 Minerals Yearbook ZIRCONIUM AND HAFNIUM

    E-print Network

    .09 Mt in 2005. Because of the closure of mines in Florida and Georgia, domestic production of zircon decreased in 2006 compared with production in 2005. Production of milled zircon and zirconium oxide mineral zircon (ZrSiO4 ). A relatively small quantity of zirconium is derived from the mineral baddeleyite

  20. 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.

  1. ZIRCONIUM AND HAFNIUM (Data in metric tons, unless otherwise noted)

    E-print Network

    192 ZIRCONIUM AND HAFNIUM (Data in metric tons, unless otherwise noted) Domestic Production and Use: Zircon sand was produced at two mines in Florida and at one mine in Virginia. Zirconium and hafnium metal. Typically, both metals are in the ore in a zirconium to hafnium ratio of about 50:1. Primary zirconium

  2. ZIRCONIUM AND HAFNIUM (Data in metric tons, unless otherwise noted)

    E-print Network

    190 ZIRCONIUM AND HAFNIUM (Data in metric tons, unless otherwise noted) Domestic Production and Use to begin operating in Georgia in 2004. Zirconium and hafnium metal were produced from zircon sand by two in a zirconium to hafnium ratio of about 50:1. Primary zirconium chemicals were produced by the Oregon metal

  3. 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.

  4. Organic derivatives of zirconium phosphate

    E-print Network

    Fine, Steven Beryl

    1980-01-01

    solution of 1 N C H OPO H solution in equal volumes of acetone and water. This was heated under reflux for ten hours. Then it was filtered, washed, and air dried. The interlayer spacing for the phenyl ester was 16. 4 A. Thermogravimetric analysis..., where one method is essentially an improvement on the other. The first synthesis is much like the method which is used to crystallize n-zirconium phos- phate [ 15]. Zirconyl chloride, hydrofluoric acid, and a phosphoric acid ester are refluxed...

  5. Nitrate and glasshouse vegetables

    Microsoft Academic Search

    JPNL Roorda Van Eysinga

    1984-01-01

    Leafy vegetables grown under glass in winter have a rather high nitrate content. Three possibilities of reducing this content are discussed: the use of nitrification inhibitors, growing on NFT and omission of nitrogen during a certain period before harvest, and the breeding of varieties with a low nitrate content.

  6. MODELED WET NITRATE DEPOSITION

    EPA Science Inventory

    Modeled data on nitrate wet deposition was obtained from Dr. Jeff Grimm at Penn State Univ. Nitrate wet depostion causes acidification and eutrophication of surface water bodies. See below regarding decriptions on how original data was produced. These data will be part of futur...

  7. The solar photospheric abundance of zirconium

    E-print Network

    Caffau, Elisabetta; Ludwig, Hans-Günter; Bonifacio, Piercarlo; Steffen, Matthias

    2010-01-01

    Zirconium (Zr), together with strontium and yttrium, is an important element in the understanding of the Galactic nucleosynthesis. In fact, the triad Sr-Y-Zr constitutes the first peak of s-process elements. Despite its general relevance not many studies of the solar abundance of Zr were conducted. We derive the zirconium abundance in the solar photosphere with the same CO5BOLD hydrodynamical model of the solar atmosphere that we previously used to investigate the abundances of C-N-O. We review the zirconium lines available in the observed solar spectra and select a sample of lines to determine the zirconium abundance, considering lines of neutral and singly ionised zirconium. We apply different line profile fitting strategies for a reliable analysis of Zr lines that are blended by lines of other elements. The abundance obtained from lines of neutral zirconium is very uncertain because these lines are commonly blended and weak in the solar spectrum. However, we believe that some lines of ionised zirconium are...

  8. Resistance Butt Welding of Zirconium Alloy Material

    Microsoft Academic Search

    D. S. Setty; Reddy P. Ravinder; A. L. N. Murthy

    2008-01-01

    Zirconium alloy is the main structural material used in the nuclear fuel production. This material has distinct advantages like less thermal neutron absorption cross-section and better chemical and mechanical properties for the reactor-working conditions. This material is widely used in boiling water and heavy water type reactors. Natural Uranium Dioxide (UO2) pellets are loaded into thin wall zirconium alloy tubes

  9. Ageing of zirconium alloy components

    NASA Astrophysics Data System (ADS)

    Chatterjee, S.; Shah, Priti Kotak; Dubey, J. S.

    2008-12-01

    India has two types (pressurized heavy water reactors (PHWRs) and boiling water reactors (BWRs)) of commercial nuclear reactors in operation, in addition to research reactors. Many of the life limiting critical components in these reactors are fabricated from zirconium alloys. The progressive degradation of these components caused by the cumulative exposure of high energy neutron irradiation with increasing period of reactor operation was monitored to assess the degree of ageing. The components/specimens examined included fuel element claddings removed from BWRs, pressure tubes and garter springs removed from PHWRs and calandria tube specimens used in PHWRs. The tests included tension test (for cladding, garter spring), fracture toughness test (for pressure tube), crush test (for garter spring), and measurement of irradiation induced growth (for calandria tube). Results of various tests conducted are presented and applications of the test results are elaborated for residual life estimation/life extension of the components.

  10. SOIL NITRATE TESTS FOR WISCONSIN

    E-print Network

    Balser, Teri C.

    SOIL NITRATE TESTS FOR WISCONSIN CROPPING SYSTEMS L.G. Bundy Dept. of Soil Science University of Wisconsin #12;Why Use Soil Nitrate Tests? · Agronomic and environmental benefits · Predict corn N needs ­ Improved accuracy ­ Site-and year-specific · Minimize nitrate loss #12;#12;Preplant Soil Nitrate Test (PPNT

  11. 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

  12. THE ALLOY SYSTEMS URANIUM-TITANIUM, URANIUM-ZIRCONIUM AND URANIUM-TITANIUM- ZIRCONIUM

    Microsoft Academic Search

    B. W. Howlett; A. G. Knapton

    1959-01-01

    Dilatometric, metallographic, x-ray, and hightemperature x-ray methods ; were employed in a study of the uranium --titanium, uranium --zirconium and ; uranium --titanium --zirconium alloy systems. The three metals are mutually ; soluble in one another in their high-temperature body-centered cubic forms, and ; about 900 deg C complete solid solubility exists. There is general agreement ; between published versions

  13. Irradiation effects on the mechanical properties of zirconium and dilute zirconium alloys: a review

    Microsoft Academic Search

    Pankaskie

    1976-01-01

    The effects of fast flux (E greater than or equal to 1 MeV) neutrons on zirconium and dilute zirconium alloys are discussed. The effects on the elastic constants, strength and ductility, creep, fatigue and fracture, and irradiation growth are reviewed. (FS)

  14. 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.

  15. 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.

  16. Screw dislocation in zirconium: an ab initio study Emmanuel Clouet

    E-print Network

    Paris-Sud XI, Université de

    Screw dislocation in zirconium: an ab initio study Emmanuel Clouet CEA, DEN, Service de Recherches in zirconium is controlled by 1/3 1¯210 screw dislocations gliding in the prism planes of the hexagonal close zirconium and is known to be related to the number of valence electrons in the d band. We use ab initio

  17. 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

  18. VACUUM PUMPING STUDY OF TITANIUM-ZIRCONIUM-VANADIUM THIN FILMS*

    E-print Network

    ERL 03-8 VACUUM PUMPING STUDY OF TITANIUM-ZIRCONIUM-VANADIUM THIN FILMS* Yulin Li# and Simon Ho performance of Titanium- Zirconium-Vanadium (TiZrV) NEG thin films was investigated to provide `engineering- Zirconium-Vanadium (TiZrV) NEG thin films, deposited on the interior of stainless steel (SST) pipes. The Ti

  19. ZIRCONIUM AND HAFNIUM (Data in metric tons unless otherwise noted)

    E-print Network

    190 ZIRCONIUM AND HAFNIUM (Data in metric tons unless otherwise noted) Domestic Production and Use minerals. Typically, zirconium and hafnium are contained in zircon at a ratio of about 50 to 1. Two firms produced zircon from surface-mining operations in Florida and Virginia. Zirconium metal and hafnium metal

  20. ZIRCONIUM AND HAFNIUM (Data in metric tons unless otherwise noted)

    E-print Network

    192 ZIRCONIUM AND HAFNIUM (Data in metric tons unless otherwise noted) Domestic Production and Use and hafnium metal were produced from zircon by two domestic producers, one in Oregon and the other in Utah. Typically, both elements are in the ore in a zirconium-to-hafnium ratio of about 50:1. Zirconium chemicals

  1. ZIRCONIUM AND HAFNIUM (Data in metric tons unless otherwise noted)

    E-print Network

    192 ZIRCONIUM AND HAFNIUM (Data in metric tons unless otherwise noted) Domestic Production and Use. Zirconium and hafnium elements were produced from zircon by two domestic producers, one in Oregon and the other in Utah. Typically, both elements are in the ore in a zirconium to hafnium ratio of about 50

  2. ZIRCONIUM AND HAFNIUM (Data in metric tons unless otherwise noted)

    E-print Network

    188 ZIRCONIUM AND HAFNIUM (Data in metric tons unless otherwise noted) Domestic Production and Use. Zirconium and hafnium metal were produced from zircon by two domestic producers, one in Oregon and the other in Utah. Typically, both elements occur in the ore in a zirconium-to-hafnium ratio of about 50:1. Primary

  3. ZIRCONIUM AND HAFNIUM (Data in metric tons unless otherwise noted)

    E-print Network

    186 ZIRCONIUM AND HAFNIUM (Data in metric tons unless otherwise noted) Domestic Production and Use and hafnium metal were produced from zircon by two domestic producers, one in Oregon and the other in Utah. Typically, both elements are in the ore in a zirconium-to-hafnium ratio of about 50:1. Zirconium chemicals

  4. ZIRCONIUM AND HAFNIUM (Data in metric tons unless otherwise noted)

    E-print Network

    188 ZIRCONIUM AND HAFNIUM (Data in metric tons unless otherwise noted) Domestic Production and Use and hafnium metal were produced from zircon by two domestic producers, one in Oregon and the other in Utah. Typically, both elements are in the ore in a zirconium-to-hafnium ratio of about 50:1. Zirconium chemicals

  5. The corrosion of zirconium under deep geologic repository conditions

    Microsoft Academic Search

    David W. Shoesmith; Dmitrij Zagidulin

    2011-01-01

    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

  6. 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.

  7. Drinking Water Problems: Nitrates 

    E-print Network

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

    2008-03-28

    three treatment methods for remov- ing nitrates/nitrites: ion exchange, reverse osmosis and electrodialysis. Reverse osmosis The most common treatment method for nitrate in a water supply is reverse osmosis (RO). This method is cost effective for a home... by passing the distilled water through a post filter. Most units will treat 5 to 11 gal- lons of water a day. Figure 4. Reverse osmosis treatment unit (Adapted from Kneen et al., 1995 and USEPA, 2003). The disadvantage of an RO unit is the small amount...

  8. 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.

  9. Structural and electrical properties of zirconium doped yttrium oxide nanostructures

    NASA Astrophysics Data System (ADS)

    Bahari, Ali; Ebrahimzadeh, Masoud; Gholipur, Reza

    2014-04-01

    A synthetic process for the formation of ZrxY1-xOy nanostructures is demonstrated by the reaction of yttrium nitrate hexahydrate with zirconium propoxide. The reactions are carried out at temperature 60°C and pressure 0.1 MPa. The energy dispersive X-ray (EDX) spectroscopy measurements confirm formation of ZrxY1-xOy nanostructures and the presence of carbonate and hydroxide species which are removed after high temperature anneals. It was found that the oxygen pressure during synthesis plays a determinant role on the structural properties of the nanostructure. This effect is further studied by atomic force microscopy (AFM) measurements and scanning electron microscope (SEM), which showed the formation of an isotopically organized structure. X-ray diffraction (XRD) measurement reveals that these changes in the nanostructural efficiency are associated with structural and compositional changes among the substrate. The dielectric constant as measured by the capacitance-voltage (C-V) technique is estimated to be around 39.05. C-V measurements taken at 1 MHz show the maximum capacitance for the Zr0.05Y0.95Oy film. The leakage current densities were below 10-5 A/cm2 for the Zr0.05Y0.95Oy film.

  10. Radiation effects on corrosion of zirconium alloys

    SciTech Connect

    Johnson, A.B. Jr.

    1989-06-01

    From the wide use of zirconium alloys as components in nuclear reactors, has come clear evidence that reactor radiation is a major corrosion parameter. The evidence emerges from comparisons of zirconium alloy corrosion behavior in different reactor types, for example, BWRs versus PWRs and in corresponding reactor loop chemistries; also, oxidation rates differ with location along components such as fuel rods and reactor pressure tubes. In most respects, oxidation effects on power reactor components are paralleled by oxidation behavior on specimens exposed to radiation in reactor loops.

  11. 7, 55535593, 2007 Nitrate aerosols

    E-print Network

    Paris-Sud XI, Université de

    ACPD 7, 5553­5593, 2007 Nitrate aerosols today and in 2030 S. E. Bauer et al. Title Page Abstract Discussions Nitrate aerosols today and in 2030: importance relative to other aerosol species and tropospheric, 5553­5593, 2007 Nitrate aerosols today and in 2030 S. E. Bauer et al. Title Page Abstract Introduction

  12. Neutronographic Texture Analysis of Zirconium Based Alloys

    Microsoft Academic Search

    M Kruželová; S Vratislav; L Kalvoda; M Dlouhá

    2012-01-01

    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

  13. Zirconium alloy heat treatment process and product

    Microsoft Academic Search

    T. J. Black; R. A. Proebstle; A. W. Urquhart; J. L. Walker; C. D. Williams

    1980-01-01

    Zirconium-base alloy channels and fuel cladding tubes having unique resistance to accelerated pustular corrosion in the boiling water reactor environment are produced by a heat treatment causing segregation of intermetallic particulate precipitate phase in two dimensional arrays preferably located along grain boundaries and subgrain boundaries throughout the alloy body.

  14. Intercalation chemistry of zirconium 4-sulfophenylphosphonate

    SciTech Connect

    Svoboda, Jan [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovský Sq. 2, 162 06 Prague 6 (Czech Republic); Zima, Vít?zslav, E-mail: vitezslav.zima@upce.cz [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovský Sq. 2, 162 06 Prague 6 (Czech Republic); Melánová, Klára [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovský Sq. 2, 162 06 Prague 6 (Czech Republic); Beneš, Ludvík [Faculty of Chemical Technology, University of Pardubice, 532 10 Pardubice (Czech Republic); Trchová, Miroslava [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovský Sq. 2, 162 06 Prague 6 (Czech Republic)

    2013-12-15

    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. - Graphical abstract: Nitrogen-containing organic compounds can be intercalated into the interlayer space of zirconium 4-sulfophenylphosphonate. - Highlights: • Zirconium 4-sulfophenylphosphonate was examined as a host material in intercalation chemistry. • A wide range of nitrogen-containing organic compounds were intercalated. • Possible arrangement of the intercalated species is described.

  15. Zirconium modified nickel-copper alloy

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. D. (inventor)

    1977-01-01

    An improved material for use in a catalytic reactor which reduces nitrogen oxide from internal combustion engines is in the form of a zirconium-modified, precipitation-strengthened nickel-copper alloy. This material has a nominal composition of Ni-30 Cu-0.2 Zr and is characterized by improved high temperature mechanical properties.

  16. Electrochemical impedance spectroscopic study of passive zirconium

    Microsoft Academic Search

    Jiahe Ai; Yingzi Chen; Mirna Urquidi-Macdonald; Digby D. Macdonald

    2008-01-01

    Spent, unreproccessed nuclear fuel is generally contained within the operational fuel sheathing fabricated from a zirconium alloy (Zircaloy 2, Zircaloy 4, or Zirlo) and is then stored in a swimming pool and\\/or dry storage facilities until permanent disposal in a licensed repository. During this period, which begins with irradiation of the fuel in the reactor during operation, the fuel sheathing

  17. 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.

  18. International strategic minerals inventory summary report; zirconium

    USGS Publications Warehouse

    Towner, R.R.

    1992-01-01

    Zircon, a zirconium silicate, is currently the most important commercial zirconium-bearing mineral. Baddeleyite, a natural form of zirconia, is less important but has some specific end uses. Both zircon and baddeleyite occur in hard-rock and placer deposits, but at present all zircon production is from placer deposits. Most baddeleyite production is from hard-rock deposits, principally as a byproduct of copper and phosphate-rock mining. World zirconium resources in identified, economically exploitable deposits are about 46 times current production rates. Of these resources, some 71 percent are in South Africa, Australia, and the United States. The principal end uses of zirconium minerals are in ceramic applications and as refractories, abrasives, and mold linings in foundries. A minor amount, mainly of zircon, is used for the production of hafnium-free zirconium metal, which is used principally for sheathing fuel elements in nuclear reactors and in the chemical-processing industry, aerospace engineering, and electronics. Australia and South Africa are the largest zircon producers and account for more than 70 percent of world output; the United States and the Soviet Union account for another 20 percent. South Africa accounts for almost all the world's production of baddeleyite, which is about 2 percent of world production of contained zirconia. Australia and South Africa are the largest exporters of zircon. Unless major new deposits are developed in countries that have not traditionally produced zircon, the pattern of world production is unlikely to change by 2020. The proportions, however, of production that come from existing producing countries may change somewhat.

  19. 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.

  20. 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.

  1. 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). 721.10089...721.10089 Modified salicylic acid, zirconium complex (generic). (a) Chemical...generically as modified salicylic acid, zirconium complex (PMN P-00-552) is...

  2. 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). 721.10089...721.10089 Modified salicylic acid, zirconium complex (generic). (a) Chemical...generically as modified salicylic acid, zirconium complex (PMN P-00-552) is...

  3. 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). 721.10089...721.10089 Modified salicylic acid, zirconium complex (generic). (a) Chemical...generically as modified salicylic acid, zirconium complex (PMN P-00-552) is...

  4. 40 CFR 471.90 - Applicability; description of the zirconium-hafnium forming subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Applicability; description of the zirconium-hafnium forming subcategory. 471.90 Section...POWDERS POINT SOURCE CATEGORY Zirconium-Hafnium Forming Subcategory § 471.90 Applicability; description of the zirconium-hafnium forming subcategory. This...

  5. 40 CFR 471.90 - Applicability; description of the zirconium-hafnium forming subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Applicability; description of the zirconium-hafnium forming subcategory. 471.90 Section...POWDERS POINT SOURCE CATEGORY Zirconium-Hafnium Forming Subcategory § 471.90 Applicability; description of the zirconium-hafnium forming subcategory. This...

  6. 40 CFR 471.90 - Applicability; description of the zirconium-hafnium forming subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Applicability; description of the zirconium-hafnium forming subcategory. 471.90 Section...POWDERS POINT SOURCE CATEGORY Zirconium-Hafnium Forming Subcategory § 471.90 Applicability; description of the zirconium-hafnium forming subcategory. This...

  7. 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...

  8. 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...

  9. Bismuth nitrate pentahydrate-induced novel nitration of eugenol

    PubMed Central

    2011-01-01

    Background Eugenol, the main constituent of clove oil possesses a number of medicinal activities. To enhance the medicinal property, structural modification is required. On the other hand, bismuth nitrate pentahydrate has been established as an excellent eco-friendly nitrating agent for several classes of organic compounds. Results Bismuth nitrate pentahydrate-induced nitration of eugenol has been investigated very thoroughly. Twenty five different conditions have been studied. The microwave-induced solvent-free reaction has been identified as the best condition. Conclusions Spectral analyses confirm that 5-nitroeugenol is the sole product in all the cases. No oxidized or isomerized product could be detected. PMID:22373430

  10. Development of Accelerated Net Nitrate Uptake 1

    PubMed Central

    MacKown, Charles T.; McClure, Peter R.

    1988-01-01

    Upon initial nitrate exposure, net nitrate uptake rates in roots of a wide variety of plants accelerate within 6 to 8 hours to substantially greater rates. Effects of solution nitrate concentrations and short pulses of nitrate (?1 hour) upon `nitrate-induced' acceleration of nitrate uptake in maize (Zea mays L.) were determined. Root cultures of dark-grown seedlings, grown without nitrate, were exposed to 250 micromolar nitrate for 0.25 to 1 hour or to various solution nitrate concentrations (10-250 micromolar) for 1 hour before returning them to a nitrate-free solution. Net nitrate uptake rates were assayed at various periods following nitrate exposure and compared to rates of roots grown either in the absence of nitrate (CaSO4-grown) or with continuous nitrate for at least 20 hours. Three hours after initial nitrate exposure, nitrate pulse treatments increased nitrate uptake rates three- to four-fold compared to the rates of CaSO4-grown roots. When cycloheximide (5 micrograms per milliliter) was included during a 1-hour pulse with 250 micromolar nitrate, development of the accelerated nitrate uptake state was delayed. Otherwise, nitrate uptake rates reached maximum values within 6 hours before declining. Maximum rates, however, were significantly less than those of roots exposed continuously for 20, 32, or 44 hours. Pulsing for only 0.25 hour with 250 micromolar nitrate and for 1 hour with 10 micromolar caused acceleration of nitrate uptake, but the rates attained were either less than or not sustained for a duration comparable to those of roots pulsed for 1 hour with 250 micromolar nitrate. These results indicate that substantial development of the nitrate-induced accelerated nitrate uptake state can be achieved by small endogenous accumulations of nitrate, which appear to moderate the activity or level of root nitrate uptake. PMID:16666094

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

    Microsoft Academic Search

    Rosecrans

    1987-01-01

    A method is described of treating cold worked zirconium alloys to reduce large grain growth during thermal treatment above its recrystallization temperature. The method comprises heating the zirconium alloy at a temperature of about 1300°F. to 1350°F. for about 1 to 3 hours subsequent to cold working the zirconium alloy and prior to the thermal treatment at a temperature of

  12. Removal of iron contaminant from zirconium chloride solution

    SciTech Connect

    Voit, D.O.

    1992-01-07

    This patent describes a process for eliminating iron contaminant from an aqueous zirconium chloride solution that has been contaminated with FeCl{sub 3} in a plant in which zirconium and hafnium chloride solutions are separated by a main MINK solvent extraction system and the FeCl{sub 3} is normally removed from the zirconium chloride solution by a secondary MINK solvent extraction system.

  13. Some strength properties of graphite-zirconium carbide composite materials

    Microsoft Academic Search

    V. S. Dergunova; A. N. Shurshakov; G. D. Posos'eva; L. N. Lutsenko

    1972-01-01

    1.Some factors influencing the strength of composite materials were examined.2.A study was made of the strength properties of graphite-zirconium carbide and graphite-zirconium carbide-zirconium composite materials having varying structures and compositions. It was found that, at 2500‡C, the tensile strength of TsG-25 type composite material is 30% higher than that of dense VPP constructional graphite.3.It was established that, by varying the

  14. Effects of nitrate supply on plant growth, nitrate accumulation, metabolic nitrate concentration and nitrate reductase activity in three leafy vegetables

    Microsoft Academic Search

    Bao-Ming Chen; Zhao-Hui Wang; Sheng-Xiu Li; Gen-Xuan Wang; Hai-Xing Song; Xi-Na Wang

    2004-01-01

    Three leafy vegetables, rape (Brassica campestris L.), Chinese cabbage (Brassica chinensis var. Oleifera Makino et Nenoto) and spinach (Spinacia oleracea L.), were grown in plastic pots with 5kg soil per pot at five nitrate supply rates, 0.00 (N1), 0.15 (N2), 0.30 (N3), 0.45 (N4), and 0.60 (N5)gNkg?1 soil to investigate the effects of nitrate supply on plant growth, nitrate accumulation

  15. Investigation of anodic oxide coatings on zirconium after heat treatment

    NASA Astrophysics Data System (ADS)

    Sowa, Maciej; Dercz, Grzegorz; Suchanek, Katarzyna; Simka, Wojciech

    2015-08-01

    Herein, results of heat treatment of zirconium anodised under plasma electrolytic oxidation (PEO) conditions at 500-800 °C are presented. The obtained oxide films were investigated by means of SEM, XRD and Raman spectroscopy. The corrosion resistance of the zirconium specimens was evaluated in Ringer's solution. A bilayer oxide coatings generated in the course of PEO of zirconium were not observed after the heat treatment. The resulting oxide layers contained a new sublayer located at the metal/oxide interface is suggested to originate from the thermal oxidation of zirconium. The corrosion resistance of the anodised metal was improved after the heat treatment.

  16. 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.

  17. Fretting-wear of zirconium alloys

    Microsoft Academic Search

    Nigel J Fisher; Murray K Weckwerth; Dwight A. E Grandison; Brian M Cotnam

    2002-01-01

    Fretting tests of Zircaloy fuel sheath bearing pads in contact with zirconium alloy (Zr–2.5Nb) pressure tube specimens were conducted at temperatures varying from 25 to 315°C. The effects of motion type and amplitude, water chemistry, fuel sheath manufacturer and pressure tube surface finish were also investigated. The effect of temperature is the most significant. The pressure tube wear coefficient in

  18. Transport properties of zirconium alloy oxide films

    Microsoft Academic Search

    H. Frank

    2002-01-01

    The conductivity mechanism of oxide films on tubes of various zirconium alloys grown in water and steam was investigated by I–V measurements. Electrodes of Ga, Ag, graphite and Au gave different results. The current decrease at voltage application was due to formation of space charge, which could be extracted again as short-circuit current. The positive branch of the I–V characteristics

  19. Fused zirconium-containing refractories of eudialyte

    Microsoft Academic Search

    M. E. Kononov; V. A. Masloboev

    1993-01-01

    Eudialyte concentrate produced in the experimental production area of the Mining Institute of the Kola Scientific Center of the Russian Academy of Sciences was used to produce fused zirconium-containing refractories. Kyanite, baddeleyite, and magnetite concentrates and also commercial alumina to TU 6-09-3428-73 were used as the production and modifying additions. The chemical analyses of the original raw materials are shown

  20. FISSION FRAGMENT RECOIL EFFECTS ON ZIRCONIUM OXIDATION

    Microsoft Academic Search

    W. C. Yee; G. H. Jenks; E. E. Stansbury

    1962-01-01

    Fission fragment recoil effects on zirconium oxidation in pure oxygen ; were studied at 1 atm pressure and 250 deg C. Specimens were oxidized under the ; following conditions: reactor radiations including recoils, reactor radiations in ; the absence of recoils, and no radiation. Irradiation experiments were conducted ; in a maximum thermal neutron flux of 8.5 x 10¹¹ neutrons\\/cm²-sec.

  1. Thermal sprayed zirconium coatings for corrosion resistance

    SciTech Connect

    Bamola, R.K.

    1992-01-01

    Vacuum Plasma Spraying (VPS) is conducted in inert reduced pressures. This results in higher particle velocities than in atmospheric plasma spraying. Reverse arc sputter cleaning and pre-heating of the workpiece lead to elevated substrate temperatures during deposition, allowing sintering of the coating and, thus, enhanced densities and bond strengths. Inert Environment Electric Arc Spraying (IEAS) is performed in inert gas chambers, utilizing wire as the feedstock. This leads to lower gas content in the coating, since the initial gas content in wire is lower than that of the powder feedstock used in VPS. Controlled atmosphere sprayed zirconium coatings had inferior mechanical and corrosion properties when compared with bulk zirconium. The VPS coatings displayed higher bond strengths and better cavitation erosion resistance than did the IEAS coatings. The IEAS coatings had lower gas content and showed better electrochemical and corrosion behavior. The lower gas content for IEAS was due to a lower initial gas level in the wire feedstock used in this process. Also, scanning electron microscopy revealed that larger particles result in the IEAS process. Thus, a smaller surface-area-to-volume ratio is available for gas-metal reactions to occur. Improvements in mechanical and corrosion properties for the IEAS coatings were due to elevated substrate temperatures during deposition. Compressive surface stresses induced by post-spray shot-peening enhanced corrosion and cavitation resistance of IEAS coatings. Coating porosity caused failure during immersion testing. Therefore, it was concluded that controlled environment thermal spraying of zirconium is not suitable for forming corrosion resistant coatings on steel. ZrN coatings were formed by electric arc spraying using a nitrogen shroud and post-spray nitriding. Two phases; ZrN and zirconium solid solution, exist in the as-sprayed coating. Nitriding increases the proportion of ZrN.

  2. Ion Exchange Reversibility of Some Radionuclides on Zirconium Tungstosuccinate and Zirconium Tungstosalicylate at their Solid-Liquid Interfaces

    Microsoft Academic Search

    B. El-Gammal; K. F. Allan

    2012-01-01

    Zirconium tungstosuccinate (ZWSu) and zirconium tungstosalicylate (ZWSa) composites were synthesized by anchoring moieties of succinic acid (SuA) and salicylic acid (SaA) onto zirconium tungstate (ZW), respectively. The produced exchange composites were unambiguously characterized by TGA, DTA, XRD, and FTIR spectroscopy. Thermally stable, amorphous, highly active, and multifunctional inorganic-organic exchangers were produced. The sorption behavior of the hybrid materials for removal

  3. Fluorometric determination of zirconium in minerals

    USGS Publications Warehouse

    Alford, W.C.; Shapiro, L.; White, C.E.

    1951-01-01

    The increasing use of zirconium in alloys and in the ceramics industry has created renewed interest in methods for its determination. It is a common constituent of many minerals, but is usually present in very small amounts. Published methods tend to be tedious, time-consuming, and uncertain as to accuracy. A new fluorometric procedure, which overcomes these objections to a large extent, is based on the blue fluorescence given by zirconium and flavonol in sulfuric acid solution. Hafnium is the only element that interferes. The sample is fused with borax glass and sodium carbonate and extracted with water. The residue is dissolved in sulfuric acid, made alkaline with sodium hydroxide to separate aluminum, and filtered. The precipitate is dissolved in sulfuric acid and electrolysed in a Melaven cell to remove iron. Flavonol is then added and the fluorescence intensity is measured with a photo-fluorometer. Analysis of seven standard mineral samples shows excellent results. The method is especially useful for minerals containing less than 0.25% zirconium oxide.

  4. Wrought zirconium and zirconium alloy seamless and welded tubes for nuclear service

    SciTech Connect

    Not Available

    1981-01-01

    The specification includes ordering information, manufacture, chemical requirements, chemical analysis, mechanical properties, permissible variations in dimensions, grain size, corrosion properties, ultrasonic inspection, hydride orientation, workmanship, inspection, certification, packaging, and marking. The specification applies to four grades of reactor grade zirconium and zirconium alloys suitable for nuclear application: R60001, R60802, R60804, and R60901. Three annexes to the specification discuss closed-end burst testing procedure, determination of hydride orientation, and ultrasonic testing. Appendixes offer an advisory guide to transducer selection and positioning. (JMT)

  5. Nitrate And Bicarbonate Selective Chemfets

    Microsoft Academic Search

    Martijn M. G. Antonisse; Johan F. J. Engbersen; David N. Reinhoudt

    1995-01-01

    The development of durable anion selective CHEMFET micro sensors is described. Selectivity in these sensors is either obtained from differences in hydration energy of the anions (the Hlofmeister series, giving nitrate selectivity) or by introduction of a new class of uranyl salophene ionophores (bicarbonate selectivity). The durability of the nitrate sensor was enhanced by using polysiloxane membranes in which 1

  6. Photoelastic Effect in Lead Nitrate

    Microsoft Academic Search

    S. Bhagavantam; K. V. Krishna Rao

    1953-01-01

    IN an earlier communication1, it was reported that barium nitrate behaves in an exceptional manner in respect of its photo-elasticity. Since then, crystals of lead nitrate have also been studied, and differences between the stress-optical constants, as determined by a Babinet compensator for the sodium D lines, are found to be: .

  7. 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.

  8. Nitrate reductase from Rhodopseudomonas sphaeroides.

    PubMed

    Kerber, N L; Cardenas, J

    1982-06-01

    The facultative phototroph Rhodopseudomonas sphaeroides DSM158 was incapable of either assimilating or dissimilating nitrate, although the organism could reduce it enzymatically to nitrite either anaerobically in the light or aerobically in the dark. Reduction of nitrate was mediated by a nitrate reductase bound to chromatophores that could be easily solubilized and functioned with chemically reduced viologens or photochemically reduced flavins as electron donors. The enzyme was solubilized, and some of its kinetic and molecular parameters were determined. It seemed to be nonadaptive, ammonia did not repress its synthesis, and its activity underwent a rapid decline when the cells entered the stationary growth phase. Studies with inhibitors and with metal antagonists indicated that molybdenum and possibly iron participate in the enzymatic reduction of nitrate. The conjectural significance of this nitrate reductase in phototrophic bacteria is discussed. PMID:6978883

  9. Nitrate reductase from Rhodopseudomonas sphaeroides.

    PubMed Central

    Kerber, N L; Cardenas, J

    1982-01-01

    The facultative phototroph Rhodopseudomonas sphaeroides DSM158 was incapable of either assimilating or dissimilating nitrate, although the organism could reduce it enzymatically to nitrite either anaerobically in the light or aerobically in the dark. Reduction of nitrate was mediated by a nitrate reductase bound to chromatophores that could be easily solubilized and functioned with chemically reduced viologens or photochemically reduced flavins as electron donors. The enzyme was solubilized, and some of its kinetic and molecular parameters were determined. It seemed to be nonadaptive, ammonia did not repress its synthesis, and its activity underwent a rapid decline when the cells entered the stationary growth phase. Studies with inhibitors and with metal antagonists indicated that molybdenum and possibly iron participate in the enzymatic reduction of nitrate. The conjectural significance of this nitrate reductase in phototrophic bacteria is discussed. PMID:6978883

  10. Fabrication of zirconium alloys into components for nuclear reactors

    Microsoft Academic Search

    Cheadle

    1977-01-01

    Over 80% of the world's annual output of zirconium is fabricated into components for nuclear reactors. In 1976 the CANadian Deuterium Uranium (CANDU) power reactor program will require nearly 500 Mg of zirconium and by 1986 the requirement will have risen to nearly 800 Mg. Most of this is fabricated into tubes which can cost as much as $80\\/kg. Small

  11. Study of the zirconium oxidation under heavy ion irradiation

    Microsoft Academic Search

    N. Bérerd; N. Moncoffre; A. Chevarier; H. Jaffrézic; H. Faust; E. Balanzat

    2006-01-01

    The objective of the present paper is to put in evidence the influence of damages due to the collision cascades which take place at the end of the heavy ion micrometer range, on the zirconium surface oxidation.A comparison between two zirconium oxidation experiments under heavy ion irradiation performed in the same temperature and pressure conditions is presented. In the first

  12. ZIRCONIUM AND HAFNIUM (Data in metric tons unless otherwise noted)

    E-print Network

    : The zirconium-silicate mineral zircon is produced as a coproduct from the mining and processing of heavy produced zircon from surface-mining operations in Florida and Virginia. Zirconium metal and hafnium metal for zircon. Other end uses of zircon include abrasives, chemicals, metal alloys, and welding rod coatings

  13. ZIRCONIUM AND HAFNIUM (Data in metric tons, unless noted)

    E-print Network

    190 ZIRCONIUM AND HAFNIUM (Data in metric tons, unless noted) Domestic Production and Use: Zircon sand was produced at two mines in Florida. Zirconium and hafnium metal were produced from zircon sand companies as well. Zirconia (ZrO2) was produced from zircon sand at plants in Alabama, New Hampshire, New

  14. 21 CFR 172.160 - Potassium nitrate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.160 Potassium nitrate. The food additive potassium nitrate may be safely...

  15. Determination of fracture strength of ?-zirconium hydrides embedded in zirconium matrix at high temperatures

    NASA Astrophysics Data System (ADS)

    Kubo, T.; Kobayashi, Y.; Uchikoshi, H.

    2013-04-01

    The fracture strength of ?-zirconium hydrides embedded in a zirconium matrix was determined at temperatures between 25 °C and 250 °C by ring tensile tests using Zircaloy-2 tubes. Essentially all of the present hydrides in the tubes were re-oriented in the radial direction by a temperature cycling treatment and then tensile stress was applied perpendicular to the hydrides to ensure that brittle fracture would occur at the hydrides. The hydrides failed in a brittle manner below 100 °C where-as the zirconium matrix itself underwent ductile fracture without hydride cracking at temperatures above 200 °C under plane stress condition. Brittle fracture of the hydrides continued to occur at temperatures up to 250 °C under plane strain condition, suggesting that the upper limit temperature for hydride fracture, Tupper, was raised by the triaxial stress state under the plane strain condition. The apparent fracture strength of the hydrides, ?hydridef, was determined at temperatures below Tupper from the measured fracture strength of the tubes, making a correction for the compressive transformation stress in the hydrides. ?hydridef was about 710 MPa at temperatures between 25 °C and 250 °C at both plane stress and plane strain conditions. The temperature dependency was very small in this temperature range. Tupper was almost equivalent to the cross-over temperature between ?hydridef and the ultimate tensile strength (UTS), which suggests that, at temperatures above Tupper, the zirconium matrix would undergo ductile fracture before the stress in the hydride is raised above ?hydridef, since UTS is smaller than ?hydridef.

  16. Ab initio study on plane defects in zirconium–hydrogen solid solution and zirconium hydride

    Microsoft Academic Search

    Yutaka Udagawa; Masatake Yamaguchi; Hiroaki Abe; Naoto Sekimura; Toyoshi Fuketa

    2010-01-01

    Hydrogen embrittlement of zirconium alloys is one of the main causes of the mechanical degradation of the fuel cladding in light water reactors, and has therefore been extensively studied. Although various conjectures have been proposed as the origin of such embrittlement, it is not known which one plays the most important role: the brittle nature of the hydride, micro-crack nucleation

  17. Evaluation of localized corrosion of zirconium in acidic chloride solutions

    SciTech Connect

    Fahey, J.; Holmes, D.; Yau, T.L. [Wah Chang, Albany, OR (United States)

    1997-01-01

    Zirconium is prone to localized corrosion in acidic chloride (Cl{sup {minus}}) solutions contaminated by oxidizing ions, such as ferric or cupric ions. This tendency can be reduced by ensuring that the zirconium surface is clean and smooth. The effect of surface condition on localized corrosion of zirconium in acidic chloride solutions was predicted using potentiodynamic polarization scans. Predictions were confirmed by mass-loss tests on various combinations of surface finish and acid concentrations. A real-time indication of localized corrosion was derived by monitoring electrochemical noise produced between two similar electrodes immersed in an acidic chloride solution. Electrochemical noise monitoring correlated well with predictions from the potentiodynamic polarization and mass-loss experiments. Electrochemical noise results showed a more anodic potential caused by ferric ion (Fe{sup 3+}) contamination might be necessary for localized corrosion but that it was not a sufficient condition. A clean zirconium surface reduced localized corrosion of zirconium.

  18. Zirconium alloy fuel cladding resistant to PCI crack propagation

    SciTech Connect

    Boyle, R.F.; Foster, J.P.

    1987-06-23

    A nuclear fuel element is described cladding tube comprising: concentric tubular layers of zirconium base alloys; the concentric tubular layers including an inner layer and outer layer; the outer layer metallurgically bonded to the inner layer; the outer layer composed of a first zirconium base alloy characterized by excellent resistance to corrosion caused by exposure to high temperature and pressure aqueous environments; the inner layer composed of a second zirconium base alloy consisting of: about 0.2 to 0.6 wt.% tin, about 0.03 to 0.11 wt.% iron, less than about 0.02 wt.% chromium, up to about 350 ppm oxygen and the remainder being zirconium and incidental impurities, and the inner layer characterized by improved resistance to crack propagation under reactor operating conditions compared to the first zirconium alloy.

  19. 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.

  20. Vacancy clustering in zirconium: an atomic scale study$ Celine Varvenne1

    E-print Network

    Paris-Sud XI, Université de

    Vacancy clustering in zirconium: an atomic scale study$ C´eline Varvenne1 , Olivier Mackain faults, Dislocation loops, Zirconium 1. Introduction Zirconium alloys are widely used in the nuclear]. These vacancy and interstitial clusters have im- portant consequences on the macroscopic behavior of zirconium

  1. Journal of Crystal Growth 307 (2007) 302308 Equilibrium analysis of zirconium carbide CVD growth

    E-print Network

    Anderson, Timothy J.

    2007-01-01

    Journal of Crystal Growth 307 (2007) 302­308 Equilibrium analysis of zirconium carbide CVD growth analysis; A3. Metalorganic chemical vapor deposition; A3. Zirconium carbide 1. Introduction Zirconium, is not straightforward particularly by chemical vapor deposition (CVD). Although atmospheric halide CVD using zirconium

  2. Diffusion thermique de l'uranium dans le zirconium. Application au stockage des gaines de combustible

    E-print Network

    Paris-Sud XI, Université de

    Diffusion thermique de l'uranium dans le zirconium. Application au stockage des gaines de centaines de µm de Zircaloy 4, un alliage dont le principal constituant est le zirconium. Durant le avons entrepris des mesures de diffusion de l'uranium dans le zirconium et l'oxyde de zirconium. Dans

  3. Irradiation growth in zirconium and its alloys

    NASA Astrophysics Data System (ADS)

    Rogerson, A.

    1988-10-01

    The UKAEA Northern Research Laboratories (Risley) have recently completed an underlying research study on irradiation growth in zirconium and its alloys. During this study, irradiation growth measurements have been made on a range of well-characterized single-crystal and polycrystalline iodide zirconium, commercial alloys Zircaloy-2 and Zr-2.5 wt% Nb, and high-purity zirconium-tin alloys in different metallurgical conditions following irradiation in the DIDO reactor at AERE Harwell. Irradiations were performed in three rigs operating at irradiation temperatures between 353 and 673 K. An important feature of the experimental programme was the capability to perform repeat length measurements on individual growth specimens at intervals during their irradiation programme. This facility has allowed accurate monitoring of the growth phenomenon and changes in growth behaviour induced by the combined effects of irradiation temperature and accumulated fast neutron dose over large dose ranges. This paper reviews the main experimental results from this programme and discusses them in terms of current understanding of the growth process. Thus, it has been observed that, in annealed Zircaloy-2 at temperatures between 553 and 673 K, a transition from saturating growth to accelerating growth rates occurs with increasing dose. The dose above which this "growth breakaway" takes place is seen to be inversely dependent on irradiation temperature in mis temperature range. The well-documented difference in growth behaviour between annealed and cold-worked Zircaloy-2 observed at relatively low irradiation temperatures, in which cold-worked material grows at a high linear rate over large dose ranges, is not observed at 673 K. Comparison is made with reported results on similar material irradiated in other irradiation facilities. The growth data are interpreted in terms of recent theories regarding the development during fast neutron irradiation of a cold-worked microstructure consisting of < a>- and < c>-type dislocations. Irradiation growth behaviour of annealed polycrystalline iodide zirconium between 353 and 673 K contrasts strongly with that in annealed Zircaloy-2 with low irradiation growth rates being observed over a large dose and temperature range. The influence of key irradiation parameters on the growth process have been examined in a series of studies initiated as part of a collaborative programme with AECL Chalk River Nuclear Labs. Final results from the studies on annealed and deformed single-crystal zirconium are reported here. They show that growth saturates rapidly at low dose in annealed single-crystal material irradiated at 353 and 553 K but that a gradual increase in growth strain is observed on irradiation to high dose at 553 K. Single-crystal specimens heavily swaged prior to irradiation at 353 K and given different pre-irradiation heat-treatments exhibit high near-linear or accelerating growth rates. These growth data are interpreted in terms of the importance of grain boundaries and twin boundaries as sinks for point defects which allow point defect separation and hence growth to continue to high dose. Finally, the results of growth experiments performed on Zr-0.1% Sn and Zr-1.5% Sn alloys at 353 and 553 K are reviewed. These experiments confirm the important role played by alloying additions and impurities on the growth process in zirconium and Zircaloy-2.

  4. EQUILIBRIUM OF THE SYSTEM LANTHANUM NITRATE-PRASEODYMIUM NITRATE-NITRIC ACID-WATER-TRIBUTYL PHOSPHATE

    Microsoft Academic Search

    B. M. Sharp; M. Smutz

    1960-01-01

    A study of the extraction characteristics of the three systems lanthanum nitrate--nitric acid--water--tributyl phosphate, praseodymium nitrate--nitric acid--water--tributyl phosphate, and lanthanum nitrate--praseodymium nitrate nitric acid -water--tributyl phosphate was conducted. The separation factors between praseodymium and lanthanum for the system lanthanum nitrate--praseodymium nitrate-nitric acid--water--tributyl phosphate were shown to be a function of the total nitrate concentration of an equilibrium phase and ;

  5. Unique photochemistry of surface nitrate

    SciTech Connect

    Vogt, R.; Finlayson-Pitts, B.J. [Univ. of California, Irvine, CA (United States)

    1995-11-23

    Unique inorganic surface nitrate species are known to be formed by the reactions of alkali halides such as solid NaCl with gaseous NO{sub 2}, HNO{sub 3}, and N{sub 2}O{sub 5}. We report here that these surface nitrate species do not give nitrite ions upon UV photolysis, unlike stable crystalline inorganic nitrates such as NaNO{sub 3}. No infrared active products are detected in the salt while the surface nitrate photodecomposes, demonstrating that the surface nitrate species has a unique photochemistry that is distinct from that of crystalline NaNO{sub 3}. On the other hand, if the surface nitrate is transformed into microcrystallites of NaNO{sub 3} through a water-induced surface reorganization, the formation of nitrite is observed upon photolysis, as expected for the stable crystalline salt. A possible mechanism for the decomposition of the surface nitrate involves production of NO{sub 2}: NO{sub 3}{sup -}{sub surf} + hv {yields} NO{sub 2} + O{sup -}{sub surf} (8) rather than NO{sub 2}{sup -} + O or ONOO{sup -} as observed in earlier studies. The atmospheric implications of these observations are discussed. 29 refs., 4 figs.

  6. 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.

  7. Electron-momentum distribution in zirconium

    SciTech Connect

    Sharma, B.K.; Ahuja, B.L.

    1988-08-15

    The electron-momentum distribution in hexagonal-close-packed zirconium has been studied for the first time with use of a Compton-scattering technique. Measurements have been made by scattering 59.54-keV ..gamma.. rays. Theoretical computations have been carried out with use of the renormalized-free-atom model for various 4d-5s configurations. Best agreement between theory and experiment is found if the electron configuration is chosen as 4d/sup 3/5s/sup 1/.

  8. Creep Behavior of Hydrogenated Zirconium Alloys

    NASA Astrophysics Data System (ADS)

    Sarkar, A.; Boopathy, K.; Eapen, J.; Murty, K. L.

    2014-10-01

    Zirconium (Zr) alloys are the primary structural materials of most water reactors. Creep is considered to be one of the important degradation mechanisms of Zr alloys during reactor operating and repository conditions. Zr alloys pick up hydrogen (H2) during their service from the coolant water. Hydrogen can be present in solid solution or precipitated hydride form in Zr alloys depending upon the temperature and concentration. This study reviews the effect of hydrogen on creep behavior of Zr alloys used in the water reactors.

  9. 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.

  10. Shell model description of zirconium isotopes

    SciTech Connect

    Sieja, K. [GSI-Helmholtzzentrum fuer Schwerionenforschung mbH., Planckstrasse 1, D-64-220 Darmstadt (Germany); Institut fuer Kernphysik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany); Nowacki, F. [Institute Pluridisciplinaire Hubert Curien, 23 rue du Loess, Strasbourg (France); Langanke, K. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany); Frankfurt Institute for Advanced Studies, D-60438 Frankfurt am Main (Germany); Martinez-Pinedo, G. [GSI-Helmholtzzentrum fuer Schwerionenforschung mbH., Planckstrasse 1, D-64-220 Darmstadt (Germany)

    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.

  11. Nitrate removal from contaminated groundwater

    SciTech Connect

    Liang, S.; Mann, M.A. [Metropolitan Water District of Southern California, La Verne, CA (United States); Guter, G.A. [Guter Consulting--Advanced Water Technology, Bakersfield, CA (United States); Kim, P.H.S.; Hardan, D.L. [Boyle Engineering Corp., Bakersfield, CA (United States)

    1999-02-01

    Data from bench-scale tests were used in conjunction with computer model simulations to develop design criteria for an ion exchange treatment process for removing nitrate. This approach is a potentially economical means of predicting nitrate breakthrough profiles, which can be used to make preliminary assessments of nitrate operating capacity, as well as the effects of changing process parameters, on the operational efficiency of various ion exchange processes. In addition, the effects of volatile various ion exchange processes. In addition, the effects of volatile organic chemicals, strong oxidants such as chlorine, and arsenic adsorption on ion exchange resin degradation were assessed.

  12. Studies of nitrate reductase in marine phytoplankton

    Microsoft Academic Search

    R. W. EPPLEY; J. L. COATSWORTH; LUCIA SOLÓRZANO

    1969-01-01

    Certain marine phytoplankton contain the enzyme nitrate rcductase when growing on nitrate, but only low levels of enzyme were found during growth with ammonium or when the nitrogen source was depleted. Netted samples of oceanic phytoplankton contained the enzyme when taken from waters with nitrate concentrations 2-10 PM. Ammonium was assimilated in preference to nitrate in phytoplankton cultures supplied with

  13. 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....

  14. 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.

  15. 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.

  16. The synthesis and characterization of Zirconium p-Phenylbis(phosphonate) Phosphate and other Zirconium Arylbis(phosphonates) for the application of ion exchange

    E-print Network

    Bellinghausen, Paul Christian

    1995-01-01

    acid group to enhance the ion exchange capacity for several cations. The synthetic routes were further adapted to synthesize Zirconium p,p'-Biphenylbis(phosphonate) Phosphate and Zirconium p,p"-Terphenylbis (phosphonate) Phosphate, in which compounds...

  17. Diphanoxy Bis(dithiocarbamato) titanium (IV)\\/zirconium (IV) Complexes

    Microsoft Academic Search

    H. P. Sangari; G. S. Sodhi; N. K. Kaushik; R. P. Singh

    1981-01-01

    Diphenoxy bis (dithiocarbamato) titanium(IV)\\/zirconium(IV) complexes of the type (C6H5O)2M(S2CNR2)2 and (C6H5O)2M(S2CNRR?)2 (where M = Ti(IV), Zr(IV), R = Me, Et, i-Pr and R? = cyclohexyl) have been prepared by the reaction of stoichiometric amounts of diphenoxy titanium (IV) dichloride and sodium salts of dithiocarbamic acid in refluxing tetrahydrofuran. The corresponding zirconium complexes have been synthesised starting from diphenoxy zirconium (IV)

  18. Factors to consider for using zirconium in sulfuric acid services

    SciTech Connect

    Fitzgerald, B.J. [Exxon Chemical Co., Baytown, TX (United States); Webber, R.G. [Exxon Chemical Co., Baton Rouge, LA (United States); Frechem, B.S. [Rohm and Haas Co., Spring House, PA (United States); Briegel, K.F. [Rohm and Haas Texas Co., Deer Park, TX (United States); Yau, T.L. [Teledyne Wah Chang, Albany, OR (United States)

    1995-10-01

    Zirconium is a pivotal material often specified for process equipment that handles highly corrosive sulfuric acid solutions. Because of the complicated nature of sulfuric acid, several factors should be addressed to ensure the durability of zirconium equipment. These factors include acid concentration, temperature, pressure, impurity, stress, crevices, welding, and surfaces condition. Depending on the situation, certain potential hazards to zirconium equipment can be prevented by applying control measures such as heat treatment, proper design and operating, inhibitor, surface conditioning and/or shot peening.

  19. Carbon-Fluorine Bond Cleavage by Zirconium Metal Hydride Complexes

    E-print Network

    Jones, William D.

    Carbon-Fluorine Bond Cleavage by Zirconium Metal Hydride Complexes Brian L. Edelbach, A. K. Fazlur, Rochester, New York 14627 Received April 8, 1999 The zirconium hydride dimer [Cp2ZrH2]2 reacts with C6F6. [Cp2ZrH2]2 reacts with C6F5H to give Cp2Zr(p-C6F4H)F, Cp2ZrF2, C6F4H2, and H2. The zirconium hydride

  20. 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.

  1. 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

  2. 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.

  3. Corrosion resistant zirconium alloy structural components and process

    Microsoft Academic Search

    R. E. Hanneman; A. W. Urquhart; D. A. Vermilyea

    1981-01-01

    Zirconium-base alloy channels, fuel cladding tubes and other components are made resistant to accelerated pustular corrosion in a boiling water reactor environment by coating them with a small amount of a suitable electronically conducting material.

  4. Fatigue behavior of alpha-zirconium phosphate/epoxy nanocomposites 

    E-print Network

    Varadharajan, Balaji R.

    2006-04-12

    Fatigue crack growth in ±-Zirconium phosphate/epoxy nanocomposites was investigated. A new fatigue testing technique was implemented for miniature samples. Two different methods ?strength of materials and Rayleigh-Ritz - were used in determining...

  5. 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

    ...products with alkanol zirconium(4+) salt and silica, acetates (generic). 721...products with alkanol zirconium(4+) salt and silica, acetates (generic). ...products with alkanol zirconium(4+) salt and silica, acetates (PMN...

  6. 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

    ...products with alkanol zirconium(4+) salt and silica, acetates (generic). 721...products with alkanol zirconium(4+) salt and silica, acetates (generic). ...products with alkanol zirconium(4+) salt and silica, acetates (PMN...

  7. 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

    ...silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica, acetates...silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica, acetates...hydrolysis products with alkanol zirconium(4+) salt and silica,...

  8. 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

    ...silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica, acetates...silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica, acetates...hydrolysis products with alkanol zirconium(4+) salt and silica,...

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

    Microsoft Academic Search

    Rosecrans

    1984-01-01

    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

  10. 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.

  11. Zirconium and hafnium with low oxygen and iron

    Microsoft Academic Search

    1988-01-01

    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

  12. Corrosion testing of stainless steel-zirconium metal waste form

    Microsoft Academic Search

    1998-01-01

    Stainless steel-zirconium (SS-Zr) alloys are being considered as waste forms for the disposition of metallic waste generated during the electrometallurgical treatment of spent nuclear fuel. The waste forms contain irradiated cladding hulls, components of the alloy fuel, noble metal fission products, and actinide elements. The baseline waste form is a stainless steel-15 wt% zirconium (SS-15Zr) alloy. This article presents microstructure

  13. Material property correlations for the niobium-1% zirconium alloy 

    E-print Network

    Senor, David James

    1989-01-01

    relationships between niobium, zirconium, and the important impurity elements (oxygen, carbon, and nittogen). Several binary and ternary diagrams of interest were studiecL Using experimental aging data, a model of the Nb-Zr-0 ternary system was developed... by Fedorov et al. (1981), shown in Figure 9. Niobium-nitrogen phase relationships were studied by Savage and Altstetter (1970), and a zirconium-nitmgen phase diagram was developed by Levinskii (1974), shown in Figure 10, Several ternary systems involving...

  14. Delayed hydride cracking of zirconium alloys

    SciTech Connect

    Yau, T.L. [Teledyne Wah Chang, Albany, OR (United States); Webster, R.T. [Webster (R.T.), Scio, OR (United States)

    1995-10-01

    High-strength zirconium alloys are susceptible to a mechanism for crack initiation and propagation termed delayed hydride cracking (DHC). In these alloys, it is possible to generate a large enough stress gradient so that hydrogen moves to the highly stressed areas. Therefore, hydrides precipitate and grow in these areas. When the tensile stress is sufficiently great, crack initiation starts at some of these hydrides. Crack propagation occurs by repeating the same process at the crack tip. Of concern for the chemical process industries is the DHC of Zr-2.5Nb welds. Results of long-term tests and case histories indicate that stress relieving is one of the major measures for preventing DHC, provided that ASME mechanical requirements are met.

  15. Resonance ionization spectroscopy of zirconium atoms

    SciTech Connect

    Page, R.H.; Dropinski, S.C.; Worden, E.F. Jr.; Stockdale, J.A.D.

    1992-05-01

    We have examined the stepwise-resonant three-photon-ionization spectrum of neutral zirconium atoms using three separately-tunable pulsed visible dye lasers. Lifetimes of even-parity levels (measured with delayed-photoionization technique) range from 10 to 100 nsec. Direct ionization cross sections appear to be less than 10{sup {minus}17} cm{sup 2}; newly-detected autoionizing levels give peak ionization cross sections (inferred from saturation fluences) up to 10{sup {minus}15} cm{sup 2}. Members of Rydberg series converging to the 315 and 1323 cm{sup {minus}1} levels of Zr{sup +} were identified. ``Clumps`` of autoionizing levels are thought to be due to Rydberg-valence mixing.

  16. Zirconium deformation behavior: insights from EBSD measurements.

    SciTech Connect

    Bingert, J. F. (John F.); Mason, T. A. (Thomas A.); Kaschner, G. C. (George C.); Maudlin, P. J. (Paul J.); Gray, G. T. (George T.), III

    2001-01-01

    The deformation of crystal-bar zirconium was investigated as a function of strain and strain rate through electron back-scattered diffraction (EBSD) characterization. The resultant data provided spatially resolved information on microstructure and texture evolution, individual twin system activity, and subsequent strain partitioning between twinned volume and parent grains. A range of deformation conditions was represented through quasi-static compression, 4-point beam bend tests at room and cryogenic temperature, and Taylor cylinder impact experiments. Effects from the interplay between slip and twinning deformation modes on anisotropic plasticity are considered in order to address the apparent trend toward isotropy at high rates. The role of various length scales on deformation behavior will be considered, along with the implications of these length scales on the assumptions typically invoked for plasticity modeling.

  17. Modelling precipitation in zirconium niobium alloys

    NASA Astrophysics Data System (ADS)

    Robson, J. D.

    2008-07-01

    A model has been developed to predict precipitation of ?-Nb in zirconium-niobium alloys. The model considers two transformation mechanisms; in situ transformation of any retained ?-Zr and homogeneous nucleation of ?-Nb. The two mechanisms are allowed to operate concurrently and compete for the available solute. The model has been calibrated and tested using data in the literature and is able to reasonably reproduce these results without introducing non-physical fitting parameters. It has then been applied to predict the effects of prior ?-Zr fraction, oxygen content, and temperature on the precipitation kinetics of ?-Nb. These calculations predict that prior ?-Zr fraction has a strong effect on the kinetics of subsequent ?-Nb evolution and that oxygen content is also critical, with higher oxygen levels predicted to result in faster kinetics and shift in the peak transformation rate to higher temperatures.

  18. On the dynamic tensile strength of Zirconium

    NASA Astrophysics Data System (ADS)

    Appleby-Thomas, G. J.; Hameed, A.; Vignjevic, R.; Hazell, P. J.; Painter, J.; Cademartori, S.

    2014-05-01

    Despite its fundamental nature, the process of dynamic tensile failure (spall) is poorly understood. Spall initiation via cracks, voids, etc, before subsequent coalesce, is known to be highly microstructure-dependant. In particular, the availability of slip planes and other methods of plastic deformation controls the onset (or lack thereof) of spall. While studies have been undertaken into the spall response of BCC and FCC materials, less attention has paid to the spall response of highly anisotropic HCP materials. Here the dynamic behaviour of zirconium is investigated via plate-impact experiments, with the aim of building on an ongoing in-house body of work investigating these highly complex materials. In particular, in this paper the effect of impact stress on spall in a commercially sourced Zr rod is considered, with apparent strain-rate softening highlighted.

  19. On the dynamic tensile strength of zirconium

    NASA Astrophysics Data System (ADS)

    Appleby-Thomas, Gareth; Hameed, Amer; Vignjevic, Rade; Siviour, Clive; Hazell, Paul; Painter, Jonathan

    2013-06-01

    Dynamic tensile failure (spall) initiation via cracks, voids, etc, before subsequent coalesce, is known to be highly microstructure-dependant. In particular, the availability of slip planes and other methods of plastic deformation controls the onset (or lack thereof) of spall. While studies have been undertaken into the spall response of BCC and FCC materials, less attention has paid to spall of highly anisotropic HCP materials. Here the dynamic behaviour of zirconium is investigated via plate-impact experiments, with the aim of building on an on-going in-house body of work investigating this complex class of materials. In particular, in this paper the effects of impact stress, pulse duration and texture on spall have been interrogated using velocimetry techniques.

  20. 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.

  1. Short-term effects of a high nitrate diet on nitrate metabolism in healthy individuals.

    PubMed

    Bondonno, Catherine P; Liu, Alex H; Croft, Kevin D; Ward, Natalie C; Puddey, Ian B; Woodman, Richard J; Hodgson, Jonathan M

    2015-03-01

    Dietary nitrate, through the enterosalivary nitrate-nitrite-NO pathway, can improve blood pressure and arterial stiffness. How long systemic nitrate and nitrite remain elevated following cessation of high nitrate intake is unknown. In 19 healthy men and women, the time for salivary and plasma nitrate and nitrite to return to baseline after 7 days increased nitrate intake from green leafy vegetables was determined. Salivary and plasma nitrate and nitrite was measured at baseline [D0], end of high nitrate diet [D7], day 9 [+2D], day 14 [+7D] and day 21 [+14D]. Urinary nitrite and nitrate was assessed at D7 and +14D. Increased dietary nitrate for 7 days resulted in a more than fourfold increase in saliva and plasma nitrate and nitrite (p < 0.001) measured at [D7]. At [+2D] plasma nitrite and nitrate had returned to baseline while saliva nitrate and nitrite were more than 1.5 times higher than at baseline levels. By [+7D] all metabolites had returned to baseline levels. The pattern of response was similar between men and women. Urinary nitrate and nitrate was sevenfold higher at D7 compared to +14D. These results suggest that daily ingestion of nitrate may be required to maintain the physiological changes associated with high nitrate intake. PMID:25774606

  2. A biological source of oceanic alkyl nitrates

    NASA Astrophysics Data System (ADS)

    Dahl, E. E.; Lewis, C. B.; Velasco, F. L.; Escobar, C.; Kellogg, D.; Velcamp, M.

    2013-12-01

    Alkyl nitrates are an important component of reactive nitrogen in the troposphere. The oceans are a source of alkyl nitrates to the atmosphere, however the source of alkyl nitrates in the oceans is unknown. It has been demonstrated that the reaction of alkyl peroxy radicals (ROO) with nitric oxide (NO) produces alkyl nitrates in the aqueous phase. We hypothesize that alkyl nitrates may be formed by organisms through the same reaction and therefore biological production could be a source of alkyl nitrates to the troposphere. This work focuses on the production of alkyl nitrates by the diatoms Chaetoceros muelleri and Thalassiosira weisfloggi. Using chemostats, we measure alkyl nitrates formed under nitrate limited conditions. We also use triggers and inhibitors of nitric oxide formation to determine if alkyl nitrate formation is affected by changes in NO production. To date, the rates of production of alkyl nitrates in our cultures, lead us to estimate a production rate on the order of femtomolar/day for C1-C3 alkyl nitrates by diatom species in the equatorial Pacific Ocean. This suggests that diatoms may contribute to the overall ocean source of alkyl nitrates; however, it is possible that other types of phytoplankton, such as cyanobacteria, that are more abundant in the open ocean, may contribute to a greater extent.

  3. 21 CFR 172.160 - Potassium nitrate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.160 Potassium nitrate. The food additive potassium nitrate may be safely used as a curing agent in the...

  4. 21 CFR 172.160 - Potassium nitrate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...HEALTH AND HUMAN SERVICES (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.160 Potassium nitrate. The food additive potassium nitrate may be safely used as a curing agent in the...

  5. 21 CFR 172.160 - Potassium nitrate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.160 Potassium nitrate. The food additive potassium nitrate may be safely used as a curing agent in the...

  6. 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.

  7. 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.

  8. Wettability of Ammonium Nitrate Prills

    Microsoft Academic Search

    QUEENIE S. M. KWOK; PEETER KRUUS; DAVID E. G. JONES

    2004-01-01

    The wettability of ammonium nitrate (AN) prills is one of the primary factors determining the physical stability and detonation behavior of ANFO. The wettabilities of various types of AN prills were compared using capillary penetration measurements. Complementary characterization studies using scanning electron microscopy (SEM) and thermogravimetry (TG) were performed to rationalize the observed differences in wettability. The wettability of AN

  9. Phosphate, Nitrate, and Sulfate Biosensors

    Microsoft Academic Search

    Aziz Amine; Giuseppe Palleschi

    2004-01-01

    Construction and assembly of phosphate, nitrate, and sulfate biosensors has been reviewed to give readers up?to?date information on the state of the art in this area which is becoming more and more important for the solution of practical problems faced in the monitoring of food safety and the environment. Special attention was paid concerning the papers published during the last

  10. 3, 59195976, 2003 The nitrate aerosol

    E-print Network

    Paris-Sud XI, Université de

    ACPD 3, 5919­5976, 2003 The nitrate aerosol field over Europe M. Schaap et al. Title Page Abstract/5919/ © European Geosciences Union 2003 Atmospheric Chemistry and Physics Discussions The nitrate aerosol field.schaap@phys.uu.nl) 5919 #12;ACPD 3, 5919­5976, 2003 The nitrate aerosol field over Europe M. Schaap et al. Title Page

  11. 8, 48114829, 2008 SOA and nitrate

    E-print Network

    Paris-Sud XI, Université de

    ACPD 8, 4811­4829, 2008 SOA and nitrate volatility in Mexico City C. J. Hennigan et al. Title Page of newly formed nitrate and water soluble organic aerosol in Mexico City C. J. Hennigan1 , A. P. Sullivan2 Geosciences Union. 4811 #12;ACPD 8, 4811­4829, 2008 SOA and nitrate volatility in Mexico City C. J. Hennigan

  12. 6, 1071310731, 2006 Nitrate photolysis on

    E-print Network

    Paris-Sud XI, Université de

    ACPD 6, 10713­10731, 2006 Nitrate photolysis on ice surfaces T. Bartels-Rausch and D. J. Donaldson Chemistry and Physics Discussions HONO and NO2 evolution from irradiated nitrate-doped ice and frozen nitrate solutions T. Bartels-Rausch1,* and D. J. Donaldson1 1 University of Toronto, Ontario M5S 3H6

  13. Spatial Inference of Nitrate Concentrations in Groundwater

    E-print Network

    West, Mike

    Spatial Inference of Nitrate Concentrations in Groundwater DAWN B. WOODARD, ROBERT L. WOLPERT on a nonparametric spatial statistical model. We apply this method to estimate nitrate concentra- tions of the fine-scale estimated nitrate concentration is obtained, as well as maps of the estimated county

  14. Measuring nitrate fluxes to assess estuarine eutrophication

    Microsoft Academic Search

    J. Newton; A. Devol; W. Ruef

    2009-01-01

    Summary form only given.The availability of nitrate sensors has enabled integration of these instruments into real-time profiling buoys and, when coupled with current meters, allows for calculation of nitrate fluxes into and out of estuaries. As the United States' estuaries are increasingly experiencing eutrophication this technological development is timely. We report on the use of nitrate sensors on our profiling

  15. 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.

  16. Nitrate removal from drinking water -- Review

    Microsoft Academic Search

    Anoop Kapoor; T. Viraraghavan

    1997-01-01

    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,

  17. Post-translational Regulation of Nitrate Reductase

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrate reductase (NR) catalyzes the reduction of nitrate to nitrite, which is the first step in the nitrate assimilation pathway, but can also reduce nitrite to nitric oxide (NO), an important signaling molecule that is thought to mediate a wide array of of developmental and physiological processes...

  18. The effect of dietary nitrate on salivary, plasma, and urinary nitrate metabolism in humans.

    PubMed

    Pannala, Ananth S; Mani, Ali R; Spencer, Jeremy P E; Skinner, Vernon; Bruckdorfer, K Richard; Moore, Kevin P; Rice-Evans, Catherine A

    2003-03-01

    Dietary nitrate is metabolized to nitrite by bacterial flora on the posterior surface of the tongue leading to increased salivary nitrite concentrations. In the acidic environment of the stomach, nitrite forms nitrous acid, a potent nitrating/nitrosating agent. The aim of this study was to examine the pharmacokinetics of dietary nitrate in relation to the formation of salivary, plasma, and urinary nitrite and nitrate in healthy subjects. A secondary aim was to determine whether dietary nitrate increases the formation of protein-bound 3-nitrotyrosine in plasma, and if dietary nitrate improves platelet function. The pharmacokinetic profile of urinary nitrate excretion indicates total clearance of consumed nitrate in a 24 h period. While urinary, salivary, and plasma nitrate concentrations increased between 4- and 7-fold, a significant increase in nitrite was only detected in saliva (7-fold). High dietary nitrate consumption does not cause a significant acute change in plasma concentrations of 3-nitrotyrosine or in platelet function. PMID:12614846

  19. Extraction of rare earth metal(III) nitrates with trialkylmethylammonium nitrate from multicomponent solutions containing ammonium nitrate

    SciTech Connect

    Pyartman, A.K.; Puzikov, E.A.; Bogatov, K.B. [St. Petersburg Technological Institute (Russian Federation)

    1994-10-20

    A study has been made of the extraction of rare earth elements (III) (praseodymium-lutetium, yttrium) by trialkylmethylammonium nitrate in kerosine (1.10 M) from binary and multicomponent solutions containing 1.0-3.0 M of ammonium nitrate. Physicochemical and mathematical models have been proposed for the distribution of individual lanthanides (III) depending on the composition of the initial raw material and on the total REE(III) and ammonium nitrate concentrations in the aqueous phase. The optimal concentration ranges for total REE and ammonium nitrate in the aqueous phase have been found for separating complex REE concentrates by using trialkylmethylammonium nitrate in the diluent.

  20. Measurement of intracellular nitrate concentrations in Chara using nitrate-selective microelectrodes

    Microsoft Academic Search

    Anthony J. Miller; Rui-Guang Zhen

    1991-01-01

    Nitrate-selective microelectrodes have been made using a quaternary ammonium sensor, methyl-tridodecylammonium nitrate, in a Polyvinylchloride matrix. These electrodes showed a log-linear response from 0.1 to 100 mol · m-3 nitrate with a typical slope of 55.6 mV per decade change in nitrate concentration. The only physiologically significant interfering anion was chloride but the lower limit of nitrate detection was 0.5

  1. Ultrafine-grain-sized zirconium by dynamic deformation , J.-M. Gebert b

    E-print Network

    Meyers, Marc A.

    Ultrafine-grain-sized zirconium by dynamic deformation B.K. Kad a , J.-M. Gebert b , M.T. Perez A polycrystalline zirconium alloy (Zircadine 702, containing 0.7% Hf) was subjected to high plastic strains (shear deformation; Zirconium; Dynamic deformation 1. Introduction Polycrystalline metals with grain sizes

  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 [MELChemicals Inc, 500 Barbertown Point Breeze Road, Flemington, NJ 08822 (United States)] [MELChemicals Inc, 500 Barbertown Point Breeze Road, Flemington, NJ 08822 (United States); Khainakov, Sergei A. [Departamento de Quimica Organica e Inorganica, Universidad de Oviedo, 33006 Oviedo (Spain)] [Departamento de Quimica Organica e Inorganica, Universidad de Oviedo, 33006 Oviedo (Spain); Garcia, Jose R., E-mail: jrgm@uniovi.es [Departamento de Quimica Organica e Inorganica, Universidad de Oviedo, 33006 Oviedo (Spain)

    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. Epitaxial growth of lead zirconium titanate thin films on Ag buffered Si substrates using rf sputtering

    E-print Network

    Laughlin, David E.

    Epitaxial growth of lead zirconium titanate thin films on Ag buffered Si substrates using rf 7 February 2007; accepted 25 March 2007; published online 23 April 2007 Epitaxial lead zirconium American Institute of Physics. DOI: 10.1063/1.2731515 The ferroelectric material lead zirconium titanate Pb

  4. Synthesis and Thermal Decomposition of a novel Zirconium Acetato-Propionate cluster: [Zr12

    E-print Network

    Paris-Sud XI, Université de

    1 Synthesis and Thermal Decomposition of a novel Zirconium Acetato-Propionate cluster: [Zr12] Sarah: +33 4 76 88 90 35 Abstract This work reports a novel Zirconium acetato-propionate complex herein called [Zr12] obtained by reaction of zirconium acetylacetonate Zr(acac)4 with propionic acid

  5. Synthesis and Structural Determination of a Hexanuclear Zirconium Glycine Compound Formed in Aqueous Solution

    E-print Network

    Li, Jing

    Synthesis and Structural Determination of a Hexanuclear Zirconium Glycine Compound Formed, Fujian 350002, P. R. China Received February 14, 2008 Single crystals of a zirconium-glycine compound-crystal X-ray diffraction. The structure revealed that it is composed of hexa-zirconium octahedral clusters

  6. Synthesis, Structure, and Metalation of Two New Highly Porous Zirconium Metal-Organic Frameworks

    E-print Network

    Yaghi, Omar M.

    Synthesis, Structure, and Metalation of Two New Highly Porous Zirconium Metal-Organic Frameworks cuboctahedral units linked by either porphyrin (MOF-525) or cruciform (MOF-535). Another zirconium) based on the zirconium(IV) cuboctahedral secondary building unit (SBU), Zr6O4(OH)4(CO2)12 (Figure 1A

  7. Zirconium oxidation under high energy heavy ion irradiation N. Brerd, A. Chevarier, N. Moncoffre, H. Jaffrezic,

    E-print Network

    Paris-Sud XI, Université de

    Zirconium oxidation under high energy heavy ion irradiation N. Bérerd, A. Chevarier, N. Moncoffre This paper concerns the study of zirconium oxidation under irradiation with high energetic Xe ions on the oxidation kinetics of zirconium. This study is performed in the framework of long-term storage of nuclear

  8. First-Principles Study of Secondary Slip in Zirconium Nermine Chaari and Emmanuel Clouet

    E-print Network

    Paris-Sud XI, Université de

    First-Principles Study of Secondary Slip in Zirconium Nermine Chaari and Emmanuel Clouet CEA, DEN, as found in iridium [8]. Cross slip is also observed in hexagonal close-packed (hcp) metals. In zirconium secondary slip in hcp metals. We fo- cus mainly on zirconium, although we checked that the FIG. 1. Hexagonal

  9. Magnetically affected texture and microstructure evolution during grain growth in Zirconium

    E-print Network

    Boyer, Edmond

    Magnetically affected texture and microstructure evolution during grain growth in Zirconium Dmitri.bozzolo@mines-paristech.fr Keywords: Grain growth, Magnetic annealing, Zirconium, Magnetic anisotropy. Abstract. The effect of a magnetic field on texture and microstructure development in cold rolled (80%) commercially pure zirconium

  10. Actinide diffusion in zirconium and the role of oxidation , H. Catalette2

    E-print Network

    Paris-Sud XI, Université de

    Actinide diffusion in zirconium and the role of oxidation N. Bérerd1 , H. Catalette2 , A. Chevarier in the cladding. Consequently, this work will be presented into two parts. The first part is devoted to zirconium presents the study of uranium diffusion in the oxidised zirconium. 2. Experimental set up 2.1 The ILL

  11. Atomic Layer Deposition of Hafnium and Zirconium Oxides Using Metal Amide Precursors

    E-print Network

    Atomic Layer Deposition of Hafnium and Zirconium Oxides Using Metal Amide Precursors Dennis M (ALD) of smooth and highly conformal films of hafnium and zirconium oxides was studied using six metal alkylamide precursors for hafnium and zirconium. Water was used as an oxygen source during these experiments

  12. J. Am. Chem. SOC.1991, 113, 3829-3837 3829 Zirconium and Hafnium Polyhydrides. Preparation and

    E-print Network

    Girolami, Gregory S.

    J. Am. Chem. SOC.1991, 113, 3829-3837 3829 Zirconium and Hafnium Polyhydrides. Preparation Abstract: Treatment of the zirconium and hafnium tetrahydroborate complexes M(BH4)4with trimethylphosphine-ligand distances in the zirconium complex are slightly longer than those in the hafnium complex, as expected from

  13. CORROSIVE WEAR BEHAVIOR OF ZIRCONIUM IN HOT SULFIDE CONTAINING ELECTROLYTES (1)

    Microsoft Academic Search

    Derrill Holmes

    The synergistic effect between corrosion and wear was determined for zirconium 702 in an aqueous medium. Zirconium 702 with a pickled surface treatment and zirconium 702 with an air oxidized surface treatment were studied. Stainless Steel 304L was used as a reference. The electrolyte used was actual Production Raw Green Liquor from the Pulp and Paper Industry. The testing conditions

  14. Dissolution of passive zirconium in electrolyte solutions: The influence of the environment

    Microsoft Academic Search

    G. M. Florianovich; E. A. Larchenko

    1995-01-01

    The anodic behavior of passive zirconium in aqueous electrolyte solutions is studied by the radiometry technique in conjunction with a variety of electrochemical methods and Auger spectroscopy. The conclusion is made that, generally, there is no direct correlation between the composition of the passivating film on zirconium and the dissolution rate of passive zirconium. Water molecules act as a passivating

  15. A case study of the development of a military specification - zirconium powder for thermal batteries

    Microsoft Academic Search

    Mary T. Burgess

    1987-01-01

    Thermal batteries are used as the critical power source in nuclear fuses, missiles, and aircraft. Heat sources in thermal batteries use a fine zirconium powder. This report focuses on the zirconium problem and the development of a military specification for zirconium powder as produced by the magnesium reduction method.

  16. Case study of the development of a military specification - zirconium powder for thermal batteries. Final report

    SciTech Connect

    Burgess, M.T.

    1987-10-01

    Thermal batteries are used as the critical power source in nuclear fuses, missiles, and aircraft. Heat sources in thermal batteries use a fine zirconium powder. This report focuses on the zirconium problem and the development of a military specification for zirconium powder as produced by the magnesium reduction method.

  17. A case study of the development of a military specification - zirconium powder for thermal batteries

    NASA Astrophysics Data System (ADS)

    Burgess, Mary T.

    1987-10-01

    Thermal batteries are used as the critical power source in nuclear fuses, missiles, and aircraft. Heat sources in thermal batteries use a fine zirconium powder. This report focuses on the zirconium problem and the development of a military specification for zirconium powder as produced by the magnesium reduction method.

  18. Nitrated fatty acids: Synthesis and measurement

    PubMed Central

    Woodcock, Steven R.; Bonacci, Gustavo; Gelhaus, Stacy L.; Schopfer, Francisco J.

    2012-01-01

    Nitrated fatty acids are the product of nitrogen dioxide reaction with unsaturated fatty acids. The discovery of peroxynitrite and peroxidase-induced nitration of biomolecules led to the initial reports of endogenous nitrated fatty acids. These species increase during ischemia reperfusion, but concentrations are often at or near the limits of detection. Here, we describe multiple methods for nitrated fatty acid synthesis, sample extraction from complex biological matrices, and a rigorous method of qualitative and quantitative detection of nitrated fatty acids by LC-MS. In addition, optimized instrument conditions and caveats regarding data interpretation are discussed. PMID:23200809

  19. Inhibition of Ice Growth and Recrystallization by Zirconium Acetate and Zirconium Acetate Hydroxide

    PubMed Central

    Mizrahy, Ortal; Bar-Dolev, Maya; Guy, Shlomit; Braslavsky, Ido

    2013-01-01

    The control over ice crystal growth, melting, and shaping is important in a variety of fields, including cell and food preservation and ice templating for the production of composite materials. Control over ice growth remains a challenge in industry, and the demand for new cryoprotectants is high. Naturally occurring cryoprotectants, such as antifreeze proteins (AFPs), present one solution for modulating ice crystal growth; however, the production of AFPs is expensive and inefficient. These obstacles can be overcome by identifying synthetic substitutes with similar AFP properties. Zirconium acetate (ZRA) was recently found to induce the formation of hexagonal cavities in materials prepared by ice templating. Here, we continue this line of study and examine the effects of ZRA and a related compound, zirconium acetate hydroxide (ZRAH), on ice growth, shaping, and recrystallization. We found that the growth rate of ice crystals was significantly reduced in the presence of ZRA and ZRAH, and that solutions containing these compounds display a small degree of thermal hysteresis, depending on the solution pH. The compounds were found to inhibit recrystallization in a manner similar to that observed in the presence of AFPs. The favorable properties of ZRA and ZRAH suggest tremendous potential utility in industrial applications. PMID:23555701

  20. Inhibition of ice growth and recrystallization by zirconium acetate and zirconium acetate hydroxide.

    PubMed

    Mizrahy, Ortal; Bar-Dolev, Maya; Guy, Shlomit; Braslavsky, Ido

    2013-01-01

    The control over ice crystal growth, melting, and shaping is important in a variety of fields, including cell and food preservation and ice templating for the production of composite materials. Control over ice growth remains a challenge in industry, and the demand for new cryoprotectants is high. Naturally occurring cryoprotectants, such as antifreeze proteins (AFPs), present one solution for modulating ice crystal growth; however, the production of AFPs is expensive and inefficient. These obstacles can be overcome by identifying synthetic substitutes with similar AFP properties. Zirconium acetate (ZRA) was recently found to induce the formation of hexagonal cavities in materials prepared by ice templating. Here, we continue this line of study and examine the effects of ZRA and a related compound, zirconium acetate hydroxide (ZRAH), on ice growth, shaping, and recrystallization. We found that the growth rate of ice crystals was significantly reduced in the presence of ZRA and ZRAH, and that solutions containing these compounds display a small degree of thermal hysteresis, depending on the solution pH. The compounds were found to inhibit recrystallization in a manner similar to that observed in the presence of AFPs. The favorable properties of ZRA and ZRAH suggest tremendous potential utility in industrial applications. PMID:23555701

  1. Deconstructing nitrate isotope dynamics in aquifers

    NASA Astrophysics Data System (ADS)

    Granger, J.

    2012-12-01

    The natural abundance N and O stable isotope ratios of nitrate provide an invaluable tool to differentiate N sources to the environment, track their dispersal, and monitor their attenuation by biological transformations. The interpretation of patterns in isotope abundances relies on knowledge of the isotope ratios of the source end-members, as well as on constraints on the isotope discrimination imposed on nitrate by respective biological processes. Emergent observations from mono-culture experiments of denitrifying bacteria reveal nitrate fractionation trends that appear at odds with trends ascribed to denitrification in soils and aquifers. This discrepancy raises the possibility that additional biological N transformations may be acting in tandem with denitrification. Here, the N and O isotope enrichments associated with nitrate removal by denitrification in aquifers are posited to bear evidence of coincident biological nitrate production - from nitrification and/or from anammox. Simulations are presented from a simple time-dependent one-box model of a groundwater mass ageing that is subject to net nitrate loss by denitrification with coincident nitrate production by nitrification or anammox. Within boundary conditions characteristic of freshwater aquifers, the apparent slope of the parallel enrichments in nitrate N and O isotopes associated with net N loss to denitrification can vary in proportion to the nitrate added simultaneous by oxidative processes. Pertinent observations from nitrate plumes in suboxic to anoxic aquifers are examined to validate this premise. In this perspective, nitrate isotope distributions suggest that we may be missing important N fluxes inherent to most aquifers.

  2. Dietary nitrate supplementation and exercise performance.

    PubMed

    Jones, Andrew M

    2014-05-01

    Dietary nitrate is growing in popularity as a sports nutrition supplement. This article reviews the evidence base for the potential of inorganic nitrate to enhance sports and exercise performance. Inorganic nitrate is present in numerous foodstuffs and is abundant in green leafy vegetables and beetroot. Following ingestion, nitrate is converted in the body to nitrite and stored and circulated in the blood. In conditions of low oxygen availability, nitrite can be converted into nitric oxide, which is known to play a number of important roles in vascular and metabolic control. Dietary nitrate supplementation increases plasma nitrite concentration and reduces resting blood pressure. Intriguingly, nitrate supplementation also reduces the oxygen cost of submaximal exercise and can, in some circumstances, enhance exercise tolerance and performance. The mechanisms that may be responsible for these effects are reviewed and practical guidelines for safe and efficacious dietary nitrate supplementation are provided. PMID:24791915

  3. Corrosion kinetics under high pressure of steam of pure zirconium and zirconium alloys followed by in situ thermogravimetry

    NASA Astrophysics Data System (ADS)

    Dali, Yacoub; Tupin, Marc; Bossis, Philippe; Pijolat, Michèle; Wouters, Yves; Jomard, François

    2012-07-01

    A new experimental thermogravimetric device has been installed to study in situ the corrosion behaviour of zirconium alloys under high pressure of steam. Corrosion tests up to 5 MPa of steam pressure have been performed on two materials, pure zirconium and Zircaloy-4 (Zy4), at around 415 °C. The rate-limiting step assumption was experimentally verified on Zy4. Unlike pure zirconium, its oxidation rate is not dependent on steam pressure. The experimental result obtained on this material is consistent with an oxygen vacancy diffusion rate-limiting step. For pure zirconium, the kinetic law is nearly linear during the corrosion process, which leads to propose an interface reaction rate-limiting step. Moreover, according to the isotope exchange experiments, the oxygen diffusion in the oxide formed on pure zirconium under high pressure of steam is very fast compared to that in the oxide of Zy4, which supports the thermogravimetric results. Finally, the impact of the SPPs on the corrosion resistance is briefly discussed in the last part of this paper from photoelectrochemical results.

  4. 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.

  5. Chemistry of zirconium related to the behavior of nuclear fuel cladding. Final report

    SciTech Connect

    Cubicciotti, D.

    1980-03-26

    Studies of the chemistry of the zirconium-iodine and zirconium-oxygen systems were undertaken to elucidate their thermodynamics and kinetics. It is anticipated that the results obtained will lead to an improved understanding of the chemical processes involved in chemically assisted fuel rod failures. This project not only has classified the thermodynamics of both the gas phase and the solids in the zirconium-iodine system, it has also provided valuable information on the chemisorption of iodine and of oxygen on zirconium surfaces at high temperatures. In addition, the kinetics of reactions on zirconium surfaces were studied. These results have already been helpful in understanding the stress corrosion cracking of Zircaloy.

  6. 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.

  7. Hot spots in ammonium nitrate

    E-print Network

    Taylor, Nicholas

    2011-07-12

    possible without the assistance of others. Corporately, Orica Mining Services and the Atomic Weapons Establishment envisioned and funded the project. From Orica, Ian Kirby, Jim Chan, John Cooper and Richard Goodridge all provided useful support, insight... sample of Nitram prills; high-purity am- monium nitrate fertilizer prills are understandably difficult to obtain from garden centres. Without Ray Flaxman and Bob Marrah of the Cavendish workshops, and Saevar Sigurdsson of the electronics workshop, it...

  8. Material property correlations for the niobium-1% zirconium alloy

    E-print Network

    Senor, David James

    1989-01-01

    in This Work. Page 2 Melting Point Data. 3 Summary of Experimental Creep Data, 4 Summary of Experimental Tensile Property Data . . 41 CHAPTER I INTRODUCTION The niobium-1% zirconium (Nb-1Zr) alloy is currently under consideration for application as a...'? Liquid o 862 C p(Z ) utah) + PRO 0. 6 )tish)+ tttNb) 6 85 utxO+ ) 0 10 20 30 40 50 60 70 80 90 100 Weiglu Petoeet Niobwm ligure 3 Niobium-Zirconium Phase Diagram (after Lundin and Cox 1960). 1050 P Sso ~)+I@) 0 1 2 3 4 5 6 7 8 9 10 11 12 13...

  9. Stress measurements during thin film zirconium oxide growth

    NASA Astrophysics Data System (ADS)

    Kim, Yong-Soo; Jeong, Yong-Hwan; Jang, Jeong-Nam

    2011-05-01

    Stress accumulation during thin film zirconium oxide growth was successfully measured using new curvature measurement technique and stress of up to 5.1 GPa was observed in an approximately 50 nm thick oxide film. Experimental results also show that steam and air oxidation make little difference in the stress profile on the oxide film thickness, especially during the early stage of oxidation. This result possibly supports the theory that zirconium corrosion kinetics crucially depends on the oxide phase transformation at the metal-oxide interface. Apparent discrepancies between previous studies were interpreted in terms of stress relaxation effects on the measurements.

  10. 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.

  11. Electrolytic production of uranous nitrate

    SciTech Connect

    Orebaugh, E.G.; Propst, R.C.

    1980-04-01

    Efficient production of uranous nitrate is important in nuclear fuel reprocessing because U(IV) acts as a plutonium reductant in solvent extraction and can be coprecipitated with plutonium and/or throium as oxalates during fuel reprocessing. Experimental conditions are described for the efficient electrolytic production of uranous nitrate for use as a reductant in the SRP Purex process. The bench-scale, continuous-flow, electrolysis cell exhibits a current efficiency approaching 100% in combination with high conversion rates of U(VI) to U(IV) in simulated and actual SRP Purex solutions. High current efficiency is achieved with a voltage-controlled mercury-plated platinum electrode and the use of hydrazine as a nitrite scavenger. Conversion of U(VI) to U(IV) proceeds at 100% efficiency. Cathodic gas generation is minimal. The low rate of gas generation permits a long residence time within the cathode, a necessary condition for high conversions on a continuous basis. Design proposals are given for a plant-scale, continuous-flow unit to meet SRP production requirements. Results from the bench-scale tests indicate that an 8-kW unit can supply sufficient uranous nitrate reductant to meet the needs of the Purex process at SRP.

  12. 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

  13. 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.

  14. 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

  15. 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)

  16. Standard Specification for Nuclear Grade Zirconium Oxide Pellets

    E-print Network

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This specification applies to pellets of stabilized zirconium oxide used in nuclear reactors. 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

  17. 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 and clad in aluminum...

  18. 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 alloys using ion implantation...

  19. 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.

  20. Phosphorus Recovery Using Zirconium-Loaded Saponified Orange Juice Residue

    NASA Astrophysics Data System (ADS)

    Harada, Hiroyuki; Kondo, Mitsunori; Biswas, Biplob K.; Ohura, Seichirou; Inoue, Katsutoshi; Ishikawa, Susumu; Kawakita, Hidetaka; Ohto, Keisuke

    Zirconium was immobilized to orange juice residue, to investigate the feasibility of using zirconium-loaded saponified orange juice residue (Zr-SOJR) for phosphorus recovery from secondary effluent and the extraction solution from incinerated sewage sludge ash by using H2SO4 and HCl. These had phosphorus concentrations of 68.2 mg/dm3 and 5.9 mg/dm3, respectively. The phosphorus removal rate secondary effluent increased with an increasing solid/liquid ratio in batch experiments. The adsorption capacity of Zr-SOJR was also compared with those obtained using a synthetic phosphorus solution and using zirconium-loaded ferrite. The prepared absorbent was effective for phosphorus removal and exhibited a reasonably high sorption capacity, twice that of zirconium ferrite. Secondary effluent was treated by packed column, and this reached break-through after 300 bed volumes. The results from phosphorous extraction from the ash indicate that can be treated with acid to efficiently recover phosphorous and thus can be absorbed by Zr-SOJR.

  1. Femtosecond laser ablation molecular isotopic spectrometry for zirconium isotope analysis.

    PubMed

    Hou, Huaming; Chan, George C-Y; Mao, Xianglei; Zorba, Vassilia; Zheng, Ronger; Russo, Richard E

    2015-05-01

    Laser ablation molecular isotopic spectrometry (LAMIS) for rapid isotopic analysis of zirconium at atmospheric pressure was studied with a femtosecond-laser system operated under high repetition rate (1 kHz) and low pulse energy (160 ?J). The temporal evolution of zirconium neutral-atomic and ionic lines, as well as zirconium oxide molecular bands, were studied. Six molecular bands, belonging to the d(3)?-a(3)? (i.e., the ? system) and E(1)?(+)-X(1)?(+) transitions, were observed with appreciable isotopic shifts. The assignments of the isotopic bandheads were first based on theoretical predictions of the band origins and the associated isotopic shifts of various dipole-allowed ZrO electronic transitions, followed by an experimental confirmation with a (94)Zr-enriched ZrO2 sample. In this work, the ?(0,1) band from the d(3)?3-a(3)?3 subsystem was utilized for Zr isotope analysis based on a compromise between the magnitude of isotopic shifts in emission wavelengths, emission strengths, signal-to-background ratios, and spectral interferences. The analysis was performed in a standardless calibration approach; the isotopic information was extracted from the experimentally measured molecular spectra through theoretical spectral fitting. The results demonstrate the feasibility to obtain isotopic information for a spectrally complicated element like zirconium, without the need to use isotopically labeled calibration standards. The availability of comprehensive molecular constants will further improve the analytical accuracy of this standardless calibration approach. PMID:25821993

  2. Ultrathin micropatterned porphyrin films assembled via zirconium phosphonate chemistry

    E-print Network

    Ultrathin micropatterned porphyrin films assembled via zirconium phosphonate chemistry Aaron M of a phosphonic-acid-functionalized porphyrin is presented and a procedure for the reproducible assembly of the porphyrins into thin films on glass or conductive glass surfaces is described. The assembly scheme, which

  3. Synthesis and characterization of mesoporous zirconium oxide thin films

    NASA Astrophysics Data System (ADS)

    Mikó, A.; Demirel, A. L.; Somer, M.

    2010-06-01

    Zirconium oxide (ZrO2) has generated wide interest because of its potential in applications such as solid oxide fuel cells, catalysts and optical devices. In these applications, it is important to control the grain size of the material and increase the surface area by introducing porosity with tailored pore size. This paper presents a synthesis route for the preparation of mesoporous zirconia using spin-coating method combined with block copolymer templating evaporation induced self assembly (EISA). The hybrid mesophase was formed by zirconium oxychloride precursor ZrOCl2·8H2O and Brij 700 poly-ethylene oxide based block copolymer template C18H37(OCH2CH2). FT-IR and Raman measurements of the hybrid mesophase provided information on the possible intermolecular interactions between the precursor and the copolymer template. The results indicate a weak ion-dipole interaction between the inorganic precursor and the organic template after the solvent evaporation, possibly directly between the zirconium and the oxygen of the poly-ethylene oxide chain. The removal of the organic block copolymer by heat treatment resulted in mesoporous zirconia with pore size of ~4-8 nm and crystalline grain size of ~10-17 nm. The morphology in thin films depended significantly on the solvent quality and the block copolymer concentration. Tailoring the surface morphology and the grain size resulted in super-hydrophilic mesoporous zirconia thin films in contrast to water contact angle of 50° on conventional tetragonal zirconium oxide.

  4. CRYSTAL STRUCTURES OF TITANIUM, ZIRCONIUM, AND HAFNIUM AT HIGH PRESSURES

    Microsoft Academic Search

    J. C. Jamieson

    1963-01-01

    At high pressures, as determined by x-ray analysis, titanium and ; zirconium metal have a distorted, bodycentered-cubic structure. This phase ; persists on pressure release. The normal hexagonal close-packed structures are ; recovered when the metals are heated. An electronic shift must occur in the ; transition. Hafnium metal showed no such transition. (auth);

  5. 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.

  6. 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...

  7. ZIRCONIUM AND HAFNIUM (Data in metric tons, unless otherwise noted)

    E-print Network

    : Zircon sand was produced at two mines in Florida. Zirconium and hafnium metal were produced from zircon companies as well. Zirconia (ZrO ) was produced from zircon sand at plants in Alabama, New Hampshire, New York, and Ohio, and the2 metal producer in Oregon. Zircon ceramics opacifiers, refractories

  8. ZIRCONIUM AND HAFNIUM (Data in metric tons, unless otherwise noted)

    E-print Network

    : Zircon sand was produced at two mines in Florida and one mine in Virginia. Zirconium and hafnium metal were produced from zircon sand by two domestic producers, one each in Oregon and Utah. Both metals other companies as well. Zirconia (ZrO2) was produced from zircon sand at plants in Alabama, New

  9. Mineral resource of the month: zirconium and hafnium

    USGS Publications Warehouse

    Gambogi, Joseph

    2007-01-01

    Zirconium and hafnium are corrosion-resistant metals that are grouped in the same family as titanium on the periodic table. The two elements commonly occur in oxide and silicate minerals and have significant economic importance in everything from ink, ceramics and golf shoes to nuclear fuel rods.

  10. ZIRCONIUM AND HAFNIUM (Data in metric tons, unless otherwise noted)

    E-print Network

    : Zircon sand was produced at two mines in Florida and one mine in Virginia. Zirconium and hafnium metal were produced from zircon sand by two domestic producers, one each in Oregon and Utah. Both metals other companies as well. Zirconia (ZrO ) was produced from zircon sand at plants in Alabama, New2

  11. Nitrate reductase activity in Zostera marina

    Microsoft Academic Search

    N. C. Roth; A. M. Pregnall

    1988-01-01

    Eelgrass (Zostera marina L.) has access to nutrient pools in both the water column and sediments. We investigated the potential for eelgrass to utilize nitrate nitrogen by measuring nitrate reductase (NR) activity with an in vivo tissue assay. Optimal incubation media contained 60 mM nitrate, 100 mM phosphate, and 0.5% 1-propanol at pH 7.0. Leaves had significantly higher NR activity

  12. Root branching responses to phosphate and nitrate.

    PubMed

    Desnos, Thierry

    2008-02-01

    Plant roots favour colonization of nutrient-rich zones in soil. Molecular genetic evidences demonstrate that roots sense and respond to local and global concentrations of inorganic phosphate and nitrate, in a fashion that depends on the shoot nutrient status. Recent investigations in Arabidopsis highlighted the role of the root tip in phosphate sensing and attributed to already known proteins (multicopper oxidases and nitrate transporters) new and unexpected functions in the root growth response to phosphate or nitrate. PMID:18024148

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

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate...Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS CARRIAGE BY...

  14. 49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate...Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS CARRIAGE BY...

  15. 49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate...Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS CARRIAGE BY...

  16. 49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...REGULATIONS CARRIAGE BY VESSEL Detailed Requirements for Class 4 (Flammable Solids), Class 5 (Oxidizers and Organic Peroxides), and Division 1.5 Materials § 176.410 Division 1.5 materials, ammonium nitrate and ammonium nitrate...

  17. Groundwater nitrate contamination: Factors and indicators

    PubMed Central

    Wick, Katharina; Heumesser, Christine; Schmid, Erwin

    2012-01-01

    Identifying significant determinants of groundwater nitrate contamination is critical in order to define sensible agri-environmental indicators that support the design, enforcement, and monitoring of regulatory policies. We use data from approximately 1200 Austrian municipalities to provide a detailed statistical analysis of (1) the factors influencing groundwater nitrate contamination and (2) the predictive capacity of the Gross Nitrogen Balance, one of the most commonly used agri-environmental indicators. We find that the percentage of cropland in a given region correlates positively with nitrate concentration in groundwater. Additionally, environmental characteristics such as temperature and precipitation are important co-factors. Higher average temperatures result in lower nitrate contamination of groundwater, possibly due to increased evapotranspiration. Higher average precipitation dilutes nitrates in the soil, further reducing groundwater nitrate concentration. Finally, we assess whether the Gross Nitrogen Balance is a valid predictor of groundwater nitrate contamination. Our regression analysis reveals that the Gross Nitrogen Balance is a statistically significant predictor for nitrate contamination. We also show that its predictive power can be improved if we account for average regional precipitation. The Gross Nitrogen Balance predicts nitrate contamination in groundwater more precisely in regions with higher average precipitation. PMID:22906701

  18. 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.

  19. Extraction of rare-earth(III) nitrates by trialkylmethylammonium nitrate from multicomponent solutions

    Microsoft Academic Search

    A. K. Pyartman; A. A. Kopyrin; E. A. Puzikov

    1994-01-01

    Extraction of rare-earth metal(III) (REM) [praseodymium-lutetium, yttrium(III)] nitrates by solutions of trialkylmethylammonium nitrate in kerosene (0.4-1.0 M) was studied. It was established that di- and trisolvates are formed in the organic phase. Extraction constants were determined. Physicochemical and mathematical models were developed to describe the extraction of REM(III) nitrates from binary and multicomponent aqueous solutions. The range of REM nitrate

  20. The effect of endogenous and externally supplied nitrate on nitrate uptake and reduction in sugarbeet seedlings

    Microsoft Academic Search

    Gisela Mäck; Rudolf Tischner

    1990-01-01

    The pericarp of the dormant sugarbeet fruit acts as a storage reservoir for nitrate, ammonium and a-amino-N. These N-reserves enable an autonomous development of the seedling for 8–10 d after imbibition. The nitrate content of the seed (1% of the whole fruit) probably induces nitrate-reductase activity in the embryo enclosed in the pericarp. Nitrate that leaks out of the pericarp

  1. The oral bioavailability of nitrate from nitrate-rich vegetables in humans

    Microsoft Academic Search

    Agnes G. van Velzen; Adrienne J. A. M. Sips; Ronald C. Schothorst; Annette C. Lambers; Jan Meulenbelt

    2008-01-01

    High dietary nitrate intake may pose a risk to human health. Since up to 80–85% of dietary nitrate intake comes from vegetables, the aim of this study was to determine the absolute bioavailability of nitrate from three nitrate-rich vegetables. In an open, four-way cross-over, single dose study, 12 human subjects underwent the following treatments: (1) intravenous infusion of 500mg sodium

  2. The NreA protein functions as a nitrate receptor in the staphylococcal nitrate regulation system.

    PubMed

    Niemann, Volker; Koch-Singenstreu, Mareike; Neu, Ancilla; Nilkens, Stephanie; Götz, Friedrich; Unden, Gottfried; Stehle, Thilo

    2014-04-01

    Staphylococci are able to use nitrate as an alternative electron acceptor during anaerobic respiration. The regulation of energy metabolism is dependent on the presence of oxygen and nitrate. Under anaerobic conditions, staphylococci employ the nitrate regulatory element (Nre) for transcriptional activation of genes involved in reduction and transport of nitrate and nitrite. Of the three proteins that constitute the Nre system, NreB has been characterized as an oxygen sensor kinase and NreC has been characterized as its cognate response regulator. Here, we present structural and functional data that establish NreA as a new type of nitrate receptor. The structure of NreA with bound nitrate was solved at 2.35Å resolution, revealing a GAF domain fold. Isothermal titration calorimetry experiments showed that NreA binds nitrate with low micromolar affinity (KD=22?M). Two crystal forms for NreA were obtained, with either bound nitrate or iodide. While the binding site is hydrophobic, two helix dipoles and polar interactions contribute to specific binding of the ions. The expression of nitrate reductase (NarGHI) was examined using a narG-lip (lipase) reporter gene assay in vivo. Expression was regulated by the presence of NreA and nitrate. Structure-guided mutations of NreA reduced its nitrate binding affinity and also affected the gene expression, thus providing support for the function of NreA as a nitrate receptor. PMID:24389349

  3. 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 ...

  4. Arabidopsis Nitrate Transporter NRT1.9 Is Important in Phloem Nitrate Transport[W][OA

    PubMed Central

    Wang, Ya-Yun; Tsay, Yi-Fang

    2011-01-01

    This study of the Arabidopsis thaliana nitrate transporter NRT1.9 reveals an important function for a NRT1 family member in phloem nitrate transport. Functional analysis in Xenopus laevis oocytes showed that NRT1.9 is a low-affinity nitrate transporter. Green fluorescent protein and ?-glucuronidase reporter analyses indicated that NRT1.9 is a plasma membrane transporter expressed in the companion cells of root phloem. In nrt1.9 mutants, nitrate content in root phloem exudates was decreased, and downward nitrate transport was reduced, suggesting that NRT1.9 may facilitate loading of nitrate into the root phloem and enhance downward nitrate transport in roots. Under high nitrate conditions, the nrt1.9 mutant showed enhanced root-to-shoot nitrate transport and plant growth. We conclude that phloem nitrate transport is facilitated by expression of NRT1.9 in root companion cells. In addition, enhanced root-to-shoot xylem transport of nitrate in nrt1.9 mutants points to a negative correlation between xylem and phloem nitrate transport. PMID:21571952

  5. THE OXIDATION AND CORROSION OF ZIRCONIUM AND ITS ALLOYS. XV. FURTHER STUDIES OF ZIRCONIUM-NIOBIUM ALLOYS

    Microsoft Academic Search

    B. Cox; P. G. Chadd; J. F. Short

    1962-01-01

    The oxidation resistance of binary and ternary zirconium alloys containing 0.5 to 5 wt% niobium and ternary additions of Sn, Cu, W, Mo, Sb, V, Ge, Pd, Pt, Fe, and Mn was studied in steam and air. The lowest oxidation rate was achieved with a Zr--1% Nb--1% Cu alloy. A study of the effect of heat treatment on the alloys

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

    SciTech Connect

    Liu, Li-Min [School of Chemistry and Chemical Engineering, The Key Laboratory of Coordination Chemistry of Jiangxi Province, Jinggangshan University, Ji’an 343009 (China); State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Lu, Guo-Yuan [State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Jiang, Li-Ping, E-mail: jianglp@nju.edu.cn [State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Zhu, Jun-Jie [State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China)

    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.

  7. Transactions of the ASABE UNCERTAINTIES IN ASSESSING ANNUAL NITRATE

    E-print Network

    Paris-Sud XI, Université de

    Transactions of the ASABE UNCERTAINTIES IN ASSESSING ANNUAL NITRATE LOADS AND CONCENTRATION the uncertainty in annual nitrate loads and concentrations (such as annual average and median concentrations, France, were analyzed. Original (high frequency) nitrate concentration and flow data were numerically

  8. 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

  9. 78 FR 32690 - Certain Ammonium Nitrate From Ukraine

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-31

    ...Review)] Certain Ammonium Nitrate From Ukraine Determination On the basis of the record...order on certain ammonium nitrate from Ukraine would be likely to lead to continuation...entitled Certain Ammonium Nitrate from Ukraine: Investigation No....

  10. NITRATE AND NITRITE CONTAMINATION IN VEGETABLES IN CHINA

    Microsoft Academic Search

    ZE-YI ZHOU; MING-JIAN WANG; JU-SI WANG

    2000-01-01

    This paper reviews recent studies of nitrate and nitrite contamination in Chinese vegetables. Nitrate and nitrite contamination is very serious and increases the amount of nitrogenous fertilizer applications. Factors influencing nitrate and nitrite contamination in vegetables are analyzed and discussed.

  11. 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.

  12. Syntheses and structural characterization of zirconium-tin and zirconium-lead binary and ternary systems

    SciTech Connect

    Kwon, Y.U.

    1991-01-28

    The binary zirconium-tin system was reinvestigated. The A15 phase appears to be a line phase with a Zr{sub 4}Sn composition. The Zr{sub 5}Sn{sub 3} (Mn{sub 5}Si{sub 3}-type) and Zr{sub 5}Sn{sub 4} (Ti{sub 5}Ga{sub 4}-type) compounds are line phases below 1000{degree}C, the latter being a self-interstitial phase of the former. ZrSn{sub 2} is the tin-richest phase. There is an one-phase region between these phases with partial self-interstitials at high temperatures. The zirconium-lead system behaves similarly: there are an A15 phase with a Zr{sub {approximately}5.8}Pb composition, Zr{sub 5}Pb{sub 3} (Mn{sub 5}Si{sub 3}-type) and Zr{sub 5}Pb{sub 4} (Ti{sub 5}Ga{sub 4-type}) compounds, and a high temperature solid solution between Zr{sub 5}Pb{sub >3.5} and Zr{sub 5}Pb{sub 4} from below 1000{degree}C; however, the ZrSn{sub 2} analogue is not formed. The Mn{sub 5}Si{sub 3}-type phases in these systems can accommodate third elements interstitially to form stoichiometric compounds Zr{sub 5}Sn{sub 3}Z (Z = B, C, N, O, Al, Si, P, S, Cu, Zn, Ga, Ge, and As and Se) and Zr{sub 5}Pb{sub 3}Z (Z = Al, Si, P, S, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Ag, Cd, In, Sn, Sb and Te) as well as their self-interstitial derivatives. The systems Zr-Sn-T, T = Fe, Co and Ni, did not produce stoichiometric interstitial phases Zr{sub 5}Sn{sub 3}T. Instead, the interstitial phases for these elements are formed only with excess tin that partially occupies the interstitial site together with a T element. Reducing the amount of tin in these systems yields two new phases; Zr{sub 5}Sn{sub 2+x}Fe{sub 1-x} (0 {le} {times} {le} 0.28) (W{sub 5}Si{sub 3}-type) and Zr{sub 6}Sn{sub 2}Fe (Zr{sub 6}Al{sub 2}Co-type) as characterized by X-ray single crystal analyses. A cobalt analogue for the latter was also synthesized.

  13. Nitric oxide, oxidants, and protein tyrosine nitration

    Microsoft Academic Search

    Rafael Radi

    2004-01-01

    The occurrence of protein tyrosine nitration under disease conditions is now firmly established and represents a shift from the signal transducing physiological actions of NO to oxidative and potentially pathogenic pathways. Tyrosine nitration is mediated by reactive nitrogen species such as peroxynitrite anion (ONOO-) and nitrogen dioxide (NO2), formed as secondary products of NO metabolism in the presence of oxidants

  14. 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...

  15. 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...

  16. Nitrate reductase in Peru current phytoplankton

    Microsoft Academic Search

    R. W. Eppley; T. T. Packard; J. J. MacIsaac

    1970-01-01

    Nitrate reductase (NR) activity was assayed by measuring the NADH-dependent formation of nitrite in phytoplankton extracts. NR specific activity increased with the nitrate concentration of the water in upwelling areas of the Peru Current. The temperature optimum for NR for natural phytoplankton was 15° to 20°C. NR activity showed diel periodicity, with maximum activity about noon and minimum activity near

  17. Winter Wheat Fertilization: Post Ammonium Nitrate

    Microsoft Academic Search

    R. Byron Irvine; Guy Lafond; Randy Kutcher

    Summary The potential for overwinter losses of nitrogen by denitrification and leaching have led to the recommendation that nitrogen fertilization of winter wheat be done using ammonium nitrate broadcast in the spring. However, spring broadcast application of urea can result in significant loss of nitrogen by volatilization and immobilization by surface residues. Since prilled ammonium nitrate is not available for

  18. 8, 1103911062, 2008 Nitrate in polar ice

    E-print Network

    Paris-Sud XI, Université de

    ACPD 8, 11039­11062, 2008 Nitrate in polar ice E. W. Wolff et al. Title Page Abstract Introduction in polar ice cores using evidence from snow and atmospheric measurements E. W. Wolff, A. E. Jones, S. J Geosciences Union. 11039 #12;ACPD 8, 11039­11062, 2008 Nitrate in polar ice E. W. Wolff et al. Title Page

  19. 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...

  20. Bacterial nitrate assimilation: gene distribution and regulation.

    PubMed

    Luque-Almagro, Víctor M; Gates, Andrew J; Moreno-Vivián, Conrado; Ferguson, Stuart J; Richardson, David J; Roldán, M Dolores

    2011-12-01

    In the context of the global nitrogen cycle, the importance of inorganic nitrate for the nutrition and growth of marine and freshwater autotrophic phytoplankton has long been recognized. In contrast, the utilization of nitrate by heterotrophic bacteria has historically received less attention because the primary role of these organisms has classically been considered to be the decomposition and mineralization of dissolved and particulate organic nitrogen. In the pre-genome sequence era, it was known that some, but not all, heterotrophic bacteria were capable of growth on nitrate as a sole nitrogen source. However, examination of currently available prokaryotic genome sequences suggests that assimilatory nitrate reductase (Nas) systems are widespread phylogenetically in bacterial and archaeal heterotrophs. Until now, regulation of nitrate assimilation has been mainly studied in cyanobacteria. In contrast, in heterotrophic bacterial strains, the study of nitrate assimilation regulation has been limited to Rhodobacter capsulatus, Klebsiella oxytoca, Azotobacter vinelandii and Bacillus subtilis. In Gram-negative bacteria, the nas genes are subjected to dual control: ammonia repression by the general nitrogen regulatory (Ntr) system and specific nitrate or nitrite induction. The Ntr system is widely distributed in bacteria, whereas the nitrate/nitrite-specific control is variable depending on the organism. PMID:22103536

  1. Polarographic determination of nitrate in vegetables

    Microsoft Academic Search

    M. I. N Ximenes; S Rath; F. G. R Reyes

    2000-01-01

    A polarographic method for the determination of nitrate in vegetables is presented. The method is based on the reduction of nitrate to nitric oxide which reacts in solution with colbalt (II) and thiocyanate ions forming an electroactive complex that is reduced at the dropping mercury electrode at ?0.5 V (vs. SCE). The nitric oxide is generated outside the polarographic cell

  2. 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...

  3. Nitrate contra auxin: nutrient sensing by roots.

    PubMed

    Beeckman, Tom; Friml, Jirí

    2010-06-15

    In a new study published in this issue of Developmental Cell, Krouk et al. reveal a surprising mechanism by which plant root systems adapt their architecture for soil exploitation. The dual transporter NRT1.1 uses both nitrate and the plant hormone auxin as substrates, enabling soil nitrate availability to regulate auxin-driven lateral root development. PMID:20627068

  4. NITRATE LEACHING IN FLORIDA URBAN ENVIRONMENTS

    E-print Network

    Ma, Lena

    ....................................................................................3 Background- Nitrate Behavior in Soil and Florida Groundwater Vulnerability.......4 Urban Ecology and application of fertilizer. Fertilizer nitrogen is a pollutant in Florida's shallow groundwater. Excessive abortions, and non-Hodgkin's lymphoma. Average groundwater background nitrate concentrations are less than 2

  5. Relationships between external nitrate availability, nitrate uptake and expression of nitrate reductase in roots of barley grown in N-limited split-root cultures

    Microsoft Academic Search

    Elisabeth Öhlén; Björn Ingemarsson; Wilbur H. Campbell; Carl-Magnus Larsson

    1995-01-01

    Despite the large number of studies of nitrate metabolism in plants, it remains undetermined to what extent this key plant system is controlled by overall plant N nutrition on the one hand, and by the nitrate ion itself on the other hand. To investigate these questions, Vmax for nitrate uptake (high-affinity range), and nitrate reductase (NR) mRNA and activity, were

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

    PubMed

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

    2013-04-01

    Dental implant alloys made from titanium and zirconium are known for their high mechanical strength, fracture toughness and corrosion resistance in comparison with commercially pure titanium. The aim of the study was to investigate possible differences in the surface chemistry and/or surface topography of titanium and titanium-zirconium surfaces after sand blasting and acid etching. The two surfaces were compared by X-ray photoelectron spectroscopy, secondary ion mass spectroscopy, scanning electron microscopy and profilometry. The 1.9 times greater surface hydrogen concentration of titanium zirconium compared to titanium was found to be the major difference between the two materials. Zirconium appeared to enhance hydride formation on titanium alloys when etched in acid. Surface topography revealed significant differences on the micro and nanoscale. Surface roughness was increased significantly (p<0.01) on the titanium-zirconium alloy. High-resolution images showed nanostructures only present on titanium zirconium. PMID:23827573

  7. Use of nitrates in ischemic heart disease.

    PubMed

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

    2015-08-01

    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

  8. Methemoglobinemia: nitrate toxicity in rural America

    SciTech Connect

    Kross, B.C.; Ayebo, A.D.; Fuortes, L.J. (University of Iowa College of Medicine, Iowa City (United States))

    1992-07-01

    Nitrates are frequently found in vegetables and ground water. Nitrate levels in ground water have increased over the past two decades because of the heightened use of nitrogenous fertilizers. Following ingestion, nitrates are converted to nitrites by fecal organisms. Nitrites are absorbed and form methemoglobin, which interferes with the oxygen-carrying capacity of hemoglobin. Infants are particularly susceptible to nitrate poisoning because fetal hemoglobin is more readily oxidized to methemoglobin. In infants, the most common source of nitrate exposure is well water, which is mixed with infant formula. Affected infants may present with asymptomatic cyanosis, which can progress to dyspnea and lethargy or coma. Blood methemoglobin concentrations are elevated. Treatment consists of the administration of oxygen and intravenous and oral methylene blue.24 references.

  9. Penetrate-leach dissolution of zirconium-clad uranium and uranium dioxide fuels

    Microsoft Academic Search

    1975-01-01

    A new decladding-dissolution process was developed for zirconium-clad uranium metal and UO fuels. The proposed penetrate-leach process consists of penetrating the zirconium cladding with Alniflex solution (2M HF--1M HNO--1M Al(NO)--0.1M KCrO) and of leaching the exposed core with 10M HNO. Undissolved cladding pieces are discarded as solid waste. Periodic HF and HNO additions, efficient agitation, and in-line zirconium analyses are

  10. Corrosion properties of amorphous iron-zirconium films in 1N sulfuric acid

    Microsoft Academic Search

    L. D. McCormick; C. L. Chien; C. R. Molock; N. S. Wheeler

    1984-01-01

    Amorphous iron-zirconium alloys, ranging in composition from FeââZrââ to FeââZrââ, hav been studied by anodic polarization and passivation decay in 1N sulfuric acid. The results showed a compositional enhancement o corrosion resistance with increasing zirconium concentration. Auger electron spectroscopy indicated that exposure to th sulfuric acid solution enhances the surface zirconium concentration with respect to the bulk of the exposed

  11. Charge-optimized many-body (COMB) potential for zirconium

    NASA Astrophysics Data System (ADS)

    Noordhoek, Mark J.; Liang, Tao; Lu, Zizhe; Shan, Tzu-Ray; Sinnott, Susan B.; Phillpot, Simon R.

    2013-10-01

    An interatomic potential for zirconium is developed within the charge-optimized many-body (COMB) formalism. The potential correctly predicts the hexagonal close-packed (HCP) structure as the ground state with cohesive energy, lattice parameters, and elastic constants matching experiment well. The most stable interstitial position is the basal octahedral followed by basal split, in agreement with recent first principles calculations. Stacking fault energies within the prism and basal planes satisfactorily match first principles calculations. A tensile test using nanocrystalline zirconium exhibits both prismatic {1 0 1bar 0}<1 1 2bar 0> slip and pyramidal {1 1 2bar 2}<1 1 2bar 3bar> slip, showing the model is capable of reproducing the mechanical deformation modes observed in experiments.

  12. New Zirconium Phosphate Fluorides: Hydrothermal Synthesis and Crystal Structures

    Microsoft Academic Search

    M. Wloka; S. I. Troyanov; E. Kemnitz

    1998-01-01

    A series of zirconium phosphate fluorides were synthesized and structurally characterized using different amines as templates. The compounds have the general formulas [amHn]1\\/n[Zr2(HPO4)(PO4)2F]·H2O (1,am=ethylenediamine,n=2; 2.am=N-methylethylenediamine,n=2; 3,am=1,3-diaminopropane,n=2; 4,am=diethylenetriamine,n=3) and [amH2]0.5[Zr2(HPO4)2(PO4)F2]·0.5H2O (5,am=N,N,N?,N?-tetramethylethylenediamine). In the structures of 2–4 with a Zr:F ratio of 2:1, there exists a three-dimensional arrangement of zirconium octahedra (one ZrO6and one ZrO5F) and phosphate tetrahedra (two PO4and one HPO4)

  13. 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.

  14. 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

  15. 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.

  16. A theoretical and experimental study of hydrides in zirconium alloys

    Microsoft Academic Search

    A. A. Shmakov; D. Yan; R. L. Eadie

    2006-01-01

    A method developed for computing the critical length and thickness of hydride plates formed in delayed hydride cracking (DHC)\\u000a in zirconium alloys is considered. The model is based on analyzing the distribution of tensile stresses in the plane of a\\u000a sharp normal tensile crack. The characteristics of hydrides formed due to DHC in reactor tubes produced from alloy Zr-2.5%\\u000a Nb

  17. Niobium-Zirconium Chronometry and Early Solar System Development

    Microsoft Academic Search

    Maria Schönbächler; Mark Rehkämper; Alex N. Halliday; Der-Chuen Lee; Michèle Bourot-Denise; Brigitte Zanda; Bodo Hattendorf; Detlef Günther

    2002-01-01

    Niobium-92 (92Nb) decays to zirconium-92 (92Zr) with a half-life of 36 million years and can be used to place constraints on the site of p-process nucleosynthesis and the timing of early solar system processes. Recent results have suggested that the initial 92Nb\\/93Nb of the solar system was high (>10-3). We report Nb-Zr internal isochrons for the ordinary chondrite Estacado (H6)

  18. Standard specification for nuclear-grade zirconium oxide powder

    E-print Network

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This specification defines the physical and chemical requirements for zirconium oxide powder intended for fabrication into shapes, either entirely or partially of zirconia, for use in a nuclear reactor core. 1.2 The material described herein shall be particulate in nature. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

  19. Trivalent zirconium and hafnium ions in yttrium oxide ceramics

    NASA Astrophysics Data System (ADS)

    Solomonov, V. I.; Spirina, A. V.; Konev, S. F.; Cholakh, S. O.

    2014-05-01

    An analysis of the electron spin resonance (ESR) spectrum of transparent ceramics composed of yttrium oxide with zirconium and hafnium additives has revealed the presence of signals (with similar parameters) from Zr3+ and Hf3+ ions, which have a similar electron configurations of the ground states: [Kr]4 d 1 and [Xe]5 d 1, respectively. It is shown that the pulsed cathodoluminescence spectra of these ions consist of two bands peaking at ? ? 818 and 900 nm.

  20. Defluoridation of Water Using Zirconium Impregnated Coconut Fiber Carbon

    Microsoft Academic Search

    R. Sai Sathish; S. Sairam; V. Guru Raja; G. Nageswara Rao; C. Janardhana

    2008-01-01

    In this study the applicability of Zirconium ion impregnated coconut fiber carbon (ZICFC) as an adsorbent for fluoride removal from water was investigated. The dependence of fluoride adsorption on the physicochemical properties includes pH, agitation time, adsorbent dosage, temperature, and the initial concentration of the adsorbate. Maximum defluoridation was obtained at an original pH value of 4.0 with a rapid

  1. Stress corrosion cracking of zirconium in nitric acid

    Microsoft Academic Search

    J. A. Beavers; J. C. Griess; W. K. Boyd

    1980-01-01

    The susceptibility of zirconium and its common alloys to stress corrosion cracking (SCC) in nitric acid was investigated by slow strain-rate and constant deflection techniques. Cracking occurred at 25°C over a wide range of acid concentrations and electrochemical potentials. The crack velocity increased slightly with increasing temperature. The failure mode was transgranular and the morphology was similar to SCC failures

  2. 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.

  3. Isothermal diffusion in uranium-plutonium-zirconium alloys

    Microsoft Academic Search

    M. C. Petri; M. A. Dayananda

    1997-01-01

    Isothermal diffusion couple experiments were performed at 1023 K to investigate diffusion phenomena in body-centered cubic U?Pu?Zr alloys. The U?Pu?Zr alloys covered the uranium-rich corner of the ternary phase diagram with plutonium concentrations up to 27 at.% and zirconium concentrations up to 20 at.%. Ternary interdiffusion coefficients were calculated at the common composition between two couples with intersecting diffusion paths.

  4. 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

  5. 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.

  6. Microbial Uranium Immobilization Independent of Nitrate Reduction

    SciTech Connect

    Madden, Andrew [ORNL; Smith, April [Florida State University; Balkwill, Dr. David [Florida State University; Fagan, Lisa Anne [ORNL; Phelps, Tommy Joe [ORNL

    2007-01-01

    At many uranium processing and handling facilities, including sites in the U.S. Department of Energy (DOE) complex, high levels of nitrate are present as co-contamination with uranium in groundwater. The daunting prospect of complete nitrate removal prior to the reduction of uranium provides a strong incentive to explore bioremediation strategies that allow for uranium bioreduction and stabilization in the presence of nitrate. Typical in-situ strategies involving the stimulation of metal-reducing bacteria are hindered by low pH environments at this study site and require that the persistent nitrate must first and continuously be removed or transformed prior to uranium being a preferred electron acceptor. This project investigates the possibility of stimulating nitrate-indifferent, pH-tolerant microorganisms to achieve bioreduction of U(VI) despite nitrate persistence. Successful enrichments from U-contaminated sediments demonstrated nearly complete reduction of uranium with very little loss of nitrate from pH 4.9-5.6 using methanol or glycerol as a carbon source. Higher pH enrichments also demonstrated similar U reduction capacity with 5-30% nitrate loss within one week. Bacterial 16S rRNA genes were amplified from uranium-reducing enrichments (pH 5.7-6.7) and sequenced. Phylogenetic analyses classified the clone sequences into four distinct clusters. Data from sequencing and T-RFLP profiles indicated that the majority of the microorganisms stimulated by these enrichment conditions consisted of low G+C Gram-positive bacteria most closely related to Clostridium and Clostridium-like organisms. This research demonstrates that the stimulation of a natural microbial community to immobilize U through bioreduction is possible without the removal of nitrate.

  7. Nitrate dry deposition measurements with surrogate surfaces

    NASA Astrophysics Data System (ADS)

    Zhu, Xiang

    Nitrate dry deposition is one of the most important topics in the study of the dry deposition of acidic and acidifying substances. This study measured nitrate dry deposition to (1) a water surface sampler (WSS) which was recently developed in the Department of Chemical and Environmental Engineering at Illinois Institute of Technology, (2) a Nylasorb filter on a knife-edge surrogate surface and (3) a greased strip on a knife-edge surrogate surface. Airborne nitric acid (HNO3), nitrous acid (HNO2), and nitrogen dioxide (NO2) concentrations were also measured concurrently with the flux measurements. These measurements were then used to evaluate the utility of using surrogate surfaces, and in particular the WSS, to measure nitrate dry deposition. The nitrogen containing species that may be responsible for nitrate dry deposition to the WSS include nitrogen monoxide (NO), NO2, peroxyacetyl nitrate (PAN), ammonia (NH3) and ammonium (NH4+), HNO2,/ HNO3, and particulate nitrate. Theoretical calculations and experiments showed that HNO3 and particulate nitrate appear to be the major nitrate contributors to the water surface sampler. Nitrate dry deposition to the water surface, Nylasorb filter and the greased strip were measured during the daytime in June and July 1995 and during both the day and night time in September and October 1995. The results showed that during the daytime in June and July the average nitrate dry deposition to the WSS (36.28 mg/m2-day) was much higher than that to the Nylasorb filter (14.04 mg/m2-day). However, during September and October there is no statistically significant difference in nitrate deposition flux between the WSS (average 4.59 mg/m2-day for the nighttime and 10.58 mg/m2-day for the daytime) and the Nylasorb filter (average 4.53 mg/m2-day for the nighttime and 8.87 mg/m2-day). A set of three experiments showed that particulate nitrate fluxes measured with the greased strip were underestimated due to the loss of volatile particulate nitrate. These experiments included a comparison of nitrate fluxes from greased strip samples extracted immediately after sampling and extracted later, a heating experiment with the greased strip samples, and a comparison between short-term and long-term greased strip samples. After precautions were taken to prevent particulate nitrate loss during sampling, a new set of samples was taken in November of 1996. The results showed that there is no statistically significant difference between the mass transfer coefficient of HNO3 (average 1.68 cm/sec) and that of sulfur dioxide (SO2) (average 1.41 cm/sec) as expected from theory. The mass transfer coefficient of HNO3 was obtained by dividing HNO3 flux (obtained by subtracting the particulate nitrate flux measured with greased strip from total nitrate flux measured with the WSS) by HNO3 concentration.

  8. 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

  9. 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

  10. 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

  11. Hydrothermal oxidation of organic wastes using reclaimed ammonium nitrate

    Microsoft Academic Search

    P. I. Proesmans; L. Luan; S. J. Buelow

    1996-01-01

    Ammonium nitrate is being studied as an alternative for ammonium perchlorate as an oxidizing agent in Department of Defense 1.1 and 1.3 rocket propellants. Use of ammonium nitrate would eliminate the HCl produced by ammonium perchlorate upon thermal decomposition. To stabilize the ammonium nitrate, which suffers from phase instability, potassium dinitramide (KDN) is added. This increased use of ammonium nitrate

  12. Review Nitrate in vegetables: toxicity, content, intake and EC regulation

    Microsoft Academic Search

    Pietro Santamaria

    Nitrate content is an important quality characteristic of vegetables. Vegetable nitrate content is of interest to governments and regulators owing to the possible implications for health and to check that controls on the content are effective. Nitrate itself is relatively non-toxic but its metabolites may produce a number of health effects. Until recently nitrate was perceived as a purely harmful

  13. Nitrate stimulation of indigenous nitrate-reducing, sulfide-oxidising bacterial community in wastewater anaerobic biofilms

    Microsoft Academic Search

    Juan Garcia-de-Lomas; Alfonso Corzo; M. Carmen Portillo; Juan M. Gonzalez; Jose A. Andrades; Cesáreo Saiz-Jimenez; Emilio Garcia-Robledo

    2007-01-01

    The role of the nitrate-reducing, sulfide-oxidising bacteria (NR-SOB) in the nitrate-mediated inhibition of sulfide net production by anaerobic wastewater biofilms was analyzed in two experimental bioreactors, continuously fed with the primary effluent of a wastewater treatment plant, one used as control (BRC) and the other one supplemented with nitrate (BRN). This study integrated information from H2S and pH microelectrodes, RNA-based

  14. STUDIES OF JOINT SOLUBILITY OF URANYL NITRATE AND NITRATES OF ALKALI EARTH METALS IN WATER

    Microsoft Academic Search

    M. A. Yakimov; N. F. Nosova; V. A. Grishin

    1958-01-01

    Isothermic solubility was studied in ternary systems Hâ O, 25, and ; 50 d . The eutectoid point for this system was not found. Three ; solubiliiy curves corresponding to the solubility of tetrahydrate of strontium ; nitrate, anhydrous strontium nitrate, and hexahydrate of uranyl nitrate ; (transition points at 37.33% UOâ(NOâ)â, 13.18% Sr(NOâ)\\/; sub 2\\/, and 5 UOâ(NOâ)â, 4.78%

  15. Phase stabilization of ammonium nitrate with binary additives consisting of potassium nitrate and complexone salts

    Microsoft Academic Search

    G. F. Klyakin; V. A. Taranushich

    2008-01-01

    The paper deals with the search for and optimization of a method for preparing phase-stabilized ammonium nitrate as oxidant\\u000a for solid propellants with environmentally friendly combustion products. The effect exerted on the energy of the V ? IV and\\u000a IV ? III polymorphous transitions of ammonium nitrate by the total content of the binary additive potassium nitrate-disodium\\u000a tetrahydrogen nitrilotris-(methylenephosphonate), component

  16. Nitrate isotope fractionations during biological nitrate reduction: Insights from first principles theoretical modeling

    Microsoft Academic Search

    W. Guo; J. Granger; D. M. Sigman

    2010-01-01

    Coupled fractionations of N and O isotopes during biological nitrate reduction provide important constraints on the marine nitrogen cycle at present and in the geologic past. Recent laboratory experiments with mono-cultures of nitrate-assimilative algae and plankton, and denitrifying bacteria demonstrate that N and O isotopic compositions of the residual nitrate co-vary linearly with a constant ratio (i.e., Deltadelta18O: Deltadelta15N) of

  17. Tetra(trihaptoallyl)zirconium(IV) Inorganic Chemistry, Vol. 12,No. 7, 1973 1535 Contribution from the Department of Chemistry, Massachusetts

    E-print Network

    Deutch, John

    Tetra(trihaptoallyl)zirconium(IV) Inorganic Chemistry, Vol. 12,No. 7, 1973 1535 Contribution from of Interchange of the Syn and Anti Protons of Tetra(trihaptuallyl)zirconium(IV)l JEANNE K. KRIEGER,* J. M. DEUTCH, and GEORGE M. WHITESIDES* Received November 6, 1972 The temperature dependence of the H nmr spectrum of tetra(trihuptoallyl)zirconium

  18. Journal of Physics and Chemistry of Solids 69 (2008) 128132 Selective MOCVD of titanium oxide and zirconium oxide thin films

    E-print Network

    Boo, Jin-Hyo

    2008-01-01

    and zirconium oxide thin films using single molecular precursors on Si(1 0 0) substrates B.-C. Kanga,Ã, D 23 June 2007; accepted 10 August 2007 Abstract Titanium oxide (TiO2) and zirconium oxide (ZrO2) thin thin film are possible. Also, zirconium oxide (ZrO2) has been extensively studied for use as a silicon

  19. Dislocation study of prismatic slip systems and their interactions in hexagonal close packed metals: application to zirconium

    E-print Network

    Devincre, Benoit

    : application to zirconium G. Monnet *, B. Devincre, L.P. Kubin Laboratoire d'Etude des Microstructures, CNRS of dislocation dynamics in single crystals of hcp zirconium are presented with emphasis on the hardening deformation stage with a low strain hardening coefficient in zirconium or titanium crystals at low temperature

  20. Astron. Nachr. / AN 999, No. 88, 789 800 (2010) / DOI please set DOI! The solar photospheric abundance of zirconium

    E-print Network

    Paris-Sud XI, Université de

    2010-01-01

    abundance of zirconium E. Caffau1,2, , R. Faraggiana3 , H.-G. Ludwig1,2 , P. Bonifacio2,4 , and M. Steffen5 ­ Hydrodynamics ­ Line: formation Zirconium (Zr), together with strontium and yttrium, is an important element derive the zirconium abundance in the solar photosphere with the same CO5BOLD hydrodynamical model

  1. SPECTRES D'ABSORPTION K DU ZIRCONIUM, DE SON OXYDE ET DE SON OXYCHLORURE (*) Par ALEXIS GANSON,

    E-print Network

    Paris-Sud XI, Université de

    298. SPECTRES D'ABSORPTION K DU ZIRCONIUM, DE SON OXYDE ET DE SON OXYCHLORURE (*) Par ALEXIS GANSON'étude par spectroscopie X des spectres d'absorption K du zirconium, de ZrO2 et ZrOCl2 anhydres et hydratés mica courbé, par transmission. On montre que la discontinuité d'absorption K du zirconium métallique

  2. Fine PMN powders prepared from nitrate solutions

    Microsoft Academic Search

    Y. Yoshikawa

    1994-01-01

    A partial coprecipitation method was developed in order to synthesize lead magnesium niobate Pb(Mg1\\/3Nb(2\\/3))O3 (PMN) powders from nitrate solutions. To obtain a niobium precursor compatible with the chemical routes, peroxo-niobium complex solutions were prepared by dissolving hydrated niobia precipitates in a dilute nitric acid solution with hydrogen peroxide. Fine PMN powders were prepared from these nitrate solutions by two-stage hydrolysis.

  3. Ammonium nitrate induced cracking of a dryer

    Microsoft Academic Search

    R. E. Clegg; R. Tomlins; M. J. Mackay

    2011-01-01

    After less than 1year of service, extensive cracking of two ammonium nitrate prill dryers was found. The cracking was found to be ammonium nitrate-induced stress corrosion cracking and the failure was attributed to a lack of post-weld stress relieving of the fabricated structures. It was considered likely that the SCC would occur more slowly once the cracks had progressed beyond

  4. Nitrate pollution of groundwater in northern China

    Microsoft Academic Search

    W. L. Zhang; Z. X. Tian; N. Zhang; X. Q. Li

    1996-01-01

    Since the 1980s, nitrogen fertiliser consumption in China has increased substantially. High nitrogen application rates may increase the potential groundwater N-pollution. These effects were investigated in 14 cities and counties in northern China. The Merckoquant-nitrate-test strip was used to measure the nitrate concentration in water. Information on well depth, groundwater level, crop rotation, yield and fertiliser application was obtained.The results

  5. Tyrosine nitration in prostaglandin H(2) synthase

    Microsoft Academic Search

    Ruba S. Deeb; Matthew J. Resnick; Dev Mittar; Timothy McCaffrey; David P. Hajjar; Rita K. Upmacis

    2002-01-01

    In this study, we investigated the effects of various nitrogen oxide (NO(x)) species on the extent of prostaglandin H(2) synthase-1 (PGHS-1) nitration in purified protein and in vascular smooth muscle cells. We also examined PGHS-1 activity under these conditions and found the degree of nitration to correlate inversely with enzyme activity. In addition, since NO(x) species are thought to invoke

  6. Electrophilic nitration of alkanes with nitronium hexafluorophosphate

    PubMed Central

    Olah, George A.; Ramaiah, Pichika; Prakash, G. K. Surya

    1997-01-01

    Nitration of alkanes such as methane, ethane, propane, n-butane, isobutane, neopentane, and cyclohexane was carried out with nitronium hexafluorophosphate in methylene chloride or nitroethane solution. Nitration of methane, albeit in poor yield, required protolytic activation of the nitronium ion. The results indicate direct electrophilic insertion of NO2+ into C 000000000000 000000000000 000000000000 000000000000 111111111111 000000000000 000000000000 000000000000 000000000000 H and CC ?-bonds. PMID:11038587

  7. Oxidation of pearlitic steels in nitrate solutions

    SciTech Connect

    Prozorov, V.V.

    1987-11-01

    The authors investigated the effect of the temperature, the time of treatment, the concentration, and the pH. They evaluated the protective properties of the oxide films obtained in the treatment of pearlitic steels in nitrate solutions according to the minimal concentration of sodium nitrate necessary for the practically complete suppression of corrosion of the investigated specimens in desalinated water at 20/sup 0/C.

  8. Synthesis of a new energetic nitrate ester

    SciTech Connect

    Chavez, David E [Los Alamos National Laboratory

    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.

  9. 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

  10. Expanded Heat Treatment to Form Residual Compressive Hoop Stress on Inner Surface of Zirconium Alloy Tubing

    Microsoft Academic Search

    Masao MEGATA

    1997-01-01

    A specific heat treatment process that introduces hoop stress has been developed. This technique can produce zirconium alloy tubing with a residual compressive hoop stress near the inner surface by taking advantage of the mechanical anisotropy in hexagonal close-packed zirconium crystal.Since a crystal having its basal pole parallel to the tangential direction of the tubing is easier to exhibit plastic

  11. Process for forming seamless tubing of zirconium or titanium alloys from welded precursors

    Microsoft Academic Search

    G. P. Sabol; R. F. Barry

    1987-01-01

    A process is described for forming seamless tubing of a material selected from zirconium, zirconium alloys, titanium, and titanium alloys, from welded precursor tubing of the material, having a heterogeneous structure resulting from the welding thereof. The process consists of: heating successive axial segments of the welded tubing, completely through the wall thereof, including the weld, to uniformly transform the

  12. Ultrasonic Estimation of Hydride Degradation of Zirconium Pressure Tubes of RBMK Fuel Channel

    Microsoft Academic Search

    Rymantas KAZYS; Reimondas SLITERIS; Liudas MAZEIKA; Algirdas VOLEISIS

    Fuel channels of nuclear reactors, which are major structural elements of a reactor core, have to meet strict requirements in terms of operational reliability. The middle part of the fuel channel, located in a graphite stack, is a tube made of a zirconium-2.5% niobium alloy. However, zirconium alloys can pick up hydrogen during operation as a consequence of corrosion reaction

  13. Inhibition by boric acid of the oxidation of zirconium in high pressure steam

    Microsoft Academic Search

    C. F. Britton; J. N. Wanklyn

    1962-01-01

    A substantial reduction in the corrosion of iodide zirconium expused to ; high pressure steam has been obtained by adding boric acid to the steam. In ; steam only at 500 deg C and l000 psi (68 at.), iodide zirconium is almost ; completely oxidised in 24 hours, weight gains of about 5400 mg\\/dm² being ; obtained. Inhibition by boric

  14. 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.

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

    SciTech Connect

    Malaestean, Iurie L. [RWTH Aachen University; Alici, Meliha Kutluca [RWTH Aachen University; Besson, Claire [RWTH Aachen University; Ellern, Arkady [Ames Laboratory; Kogerler, Paul [RWTH Aachen University

    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.

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

    SciTech Connect

    Malaestean, Lurie [RWTH Aachen University; Alici, Meliha Kutluca [RWTH Aachen University; Besson, Claire [RWTH Aachen University; Ellern, Arkady [Ames Laboratory; Kogerler, Paul [RWTH Aachen University

    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.

  17. Zirconium, Niobium, Antimony and Fluorine in Mice : Effects on growth, survival and tissue levels

    Microsoft Academic Search

    HENRY A. SCHROEDER; MARIAN MITCHENER; JOSEPH J. BALASSA

    To evaluate innate effects of certain trace elements, 540 mice were fed a diet of rye, corn oil and dried skim milk containing moderate amounts of zirconium and niobium and no detectable antimony or fluorine, in an environment relatively free of trace contaminants. Groups of 108, divided as to sex, were given 5 ppm zirconium, niobate or antimony or 10

  18. Inorganic ion-exchangers for the removal of zirconium, hafnium and niobium radioisotopes from aqueous solutions

    Microsoft Academic Search

    A. Dyer; F. H. Kadhim

    1989-01-01

    Studies were made on the uptake of zirconium, hafnium and niobium isotopes onto zeolites and amorphous zirconium phosphate. Ion exchange capacities and distribution coefficients were determined and the influence of pH examined. Kinetic experiments were made to determine the rates of uptake of the radioisotopes on the exchangers and to measure the leaching of isotopes from preloaded exchangers by synthetic

  19. Synthesis, Characterization, and Activation of Zirconium and Hafnium Dialkyl Complexes that Contain a

    E-print Network

    Müller, Peter

    Synthesis, Characterization, and Activation of Zirconium and Hafnium Dialkyl Complexes that Contain of zirconium and hafnium complexes, [MepyN]MX2 (M ) Zr, X ) NMe2, Cl, OSO2CF3, CH2CHMe2, CH2Ph; M ) Hf, X ) NMe

  20. DIFFUSION OF OXYGEN IN ZIRCONIUM AND ITS RELATION TO OXIDATION AND CORROSION

    Microsoft Academic Search

    J. Paul Pemsler

    1958-01-01

    The diffusion of oxygen in zinonium and dilute zirconium alloys has been ; studied in the temperature rsmge of 400 deg to 585 deg C by observing the rates ; of dissolution of anodically deposited interference oxide films. The diffusion ; coefficient of oxygen in zirconium depends on the grain orientation and varies by ; a factor of two among

  1. Anodic behaviour of zirconium and its alloys in fluorinated nitric media dissolution-passivation model

    Microsoft Academic Search

    J. Prong; T. Jaszay; A. Caprani; J. P. Frayret

    1995-01-01

    Current-potential curves for zirconium in fluorinated nitric medium were obtained using a rotating disc electrode. The curves exhibited four different domains according to the potential, and suggested a seven-step reaction model composed of three competing paths. Quantitatively verified by comparing computed and experimental curves, this model accounts for the behaviour of either zirconium or its main industrial alloy, Zircaloy 4,

  2. THE KINETICS OF THE CORROSION OF LOW-HAFNIUM ZIRCONIUM IN AQUEOUS SULFURIC ACID SOLUTIONS

    Microsoft Academic Search

    Tennyson Smith

    1960-01-01

    The rates of corrosion of low-hafnium zirconium in aqueous sulfuric acid ; solutions over the concentration range 9 to 97% by weight, were studied. ; Corrosion was detected by measuring the concentration of zirconium in solution ; with a radioactive tracer, Zr⁹⁵. The samples first were etched in an ; aqueous hydrofluoric-nitric acid solution then placed directly into the sulfuric

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

    DOEpatents

    Cawley, William E. (Richland, WA); Trapp, Turner J. (Richland, WA)

    1984-10-09

    A composition is described useful in the production of tritium in a nuclear eactor. 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.

  4. Diffusion in uranium alloys with zirconium. Analysis of the concentration behavior of the activation energy

    Microsoft Academic Search

    Yu. A. Shevchuk

    1997-01-01

    Uranium metal and alloys based on it are of interest as materials for fast-reactor fuel. A comprehensive investigation of the thermodynamic and diffusion properties of uranium alloys with zirconium permits drawing several fundamental conclusions that could be valid not only for this system but for other alloys as well. Thermodynamic data on the -),-phase alloys of the uranium-zirconium system are

  5. The initiation of delayed hydride cracking in zirconium-2.5 niobium

    Microsoft Academic Search

    Derong Yan

    1999-01-01

    This thesis contains two parts of work that study the initiation of the delayed hydride cracking (DHC) in zirconium alloys in different aspects. The first part is a theoretical work in which the effect of stress on the hydride precipitation solvus in zirconium, is studied from the view point of thermodynamics. The material equilibrium of a closed thermodynamic system which

  6. 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

  7. Protein tyrosine nitration in the cell cycle

    SciTech Connect

    Jia, Min, E-mail: min.jia@ki.se [Department of Oncology-Pathology, Karolinska Institutet, Stockholm (Sweden)] [Department of Oncology-Pathology, Karolinska Institutet, Stockholm (Sweden); Mateoiu, Claudia; Souchelnytskyi, Serhiy [Department of Oncology-Pathology, Karolinska Institutet, Stockholm (Sweden)] [Department of Oncology-Pathology, Karolinska Institutet, Stockholm (Sweden)

    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.

  8. 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

  9. Control and monitoring of the localized corrosion of zirconium in acidic chloride solutions

    SciTech Connect

    Fahey, J.; Holmes, D.; Yau, T.L. [Teledyne Wah Chang, Albany, OR (United States)

    1995-09-01

    Zirconium in acidic chloride solutions which are contaminated with ferric or cupric cations is prone to localized corrosion. This tendency can be reduced by ensuring that the zirconium surface is clean and smooth. In this paper, the effect of surface condition on the localized corrosion of zirconium in acidic chloride solutions is predicted with potentiodynamic scans. These predictions are confirmed by weight loss tests on various combinations of surface finish and acid concentrations. A real time indication of localized corrosion is seen by monitoring the electrochemical noise produced between two similar electrodes immersed in an acidic chloride solutions. Electrochemical noise monitoring correlates well with the predictions from potentiodynamic and weight loss experiments. The electrochemical noise results show that while an elevated (more anodic) potential caused by ferric ion contamination may be a necessary condition for localized corrosion, it is not a sufficient condition: A smooth, clean zirconium surface reduces the localized corrosion of zirconium.

  10. Factors affecting the stress corrosion cracking susceptibility of zirconium in 90% nitric acid

    SciTech Connect

    Yau, T.L.

    1988-10-01

    U-band, C-ring, and slow strain rate tests were performed to evaluate the effects of texture, stress, surface condition, heat treatments electrochemical potential, and strain rate on stress corrosion cracking (SCC) of zirconium in 90% nitric acid at room temperature. Careful control of texture, surface condition (scratching, cleaning, and oxide coating), and/or applied stress was shown to effectively lead to the prevention of SCC of zirconium in 90% HNO/sub 3/. Heat treating at 760, 880, or 1000 C does not seem to improve the SCC resistance. However, if the potential of zirconium is maintained at 500 mV/sub SCE/ or lower, or 200 ppm of HF is added, zirconium's SCC susceptibility in 90% HNO/sub 3/ is eliminated. When adding HF, zirconium sponge must also be added to avoid corrosion rates.

  11. 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.

  12. Fundamental studies into zirconium modified phosphonic acid based ionic membranes

    NASA Astrophysics Data System (ADS)

    Schlichting, Gregory Joseph

    The demand for a sustainable energy economy requires the development of new solid stare electrochemical energy conversion devices. Ionic membranes are the bases for most of these devices. Solid super acids based on zirconium phosphonates show great promise for development into these membranes. Copolymers of vinyl phosphonic acid with zirconium vinyl phosphonate have been synthesized via UV free radical polymerization from immiscible mixtures into amorphous, transparent, water stable, flexible membranes. Ion exchange capacities range from 6 to 10 meq/g corresponding to equivalent weights well below 200 g/mol. A 20wt% loading of the VZP co-monomer is XRD amorphous. It is shown that 1.5 of the 2 protons in the beginning acidic groups are dissociated in the 20wt% VZP loaded ionomer allowing these materials to have high proton conductivities, up to and exceeding 0.1 S cm^-1 at 80°C and 80%RH. Water uptake measurementsshow very little swelling of the material below 70%RH and ca. 1 water per proton at low RH. Proton conductivity under dry conditions, roughly 0.05 S cm-1 with a lambda < 1, indicates that the material conducts protons under limiting hydration conditions and strongly implicates transport by a pure Grotthuss mechanism. Through this work, it has been demonstrated that zirconium vinyl phosphonate can, in fact, be dispersed and incorporated into a polymer to create new, hybrid organic-inorganic ionomers. High conductivities over 0.15 S/cm have been shown for multiple formulations of these ionomers, which is approaching conductivities that are comparable to liquid and molten phosphoric and phosphonic acids. Phosphonic acid functionalization yielded high proton conductivities, however the increased ionic character rendered the ionomer vulnerable to attack from water. Annealing provides a rise in conductivity at 150 degrees Celsius, but shows decreases after heating to 175 degrees Celsius, where the ionomer is obviously starting to degrade.

  13. Solubility of uranyl nitrate in nitric acid solutions of aluminum nitrate

    Microsoft Academic Search

    B. K. Medkov; M. R. Petrov; O. N. Roslyakova

    1988-01-01

    The solubility of uranyl nitrate in nitric acid solutions of aluminum nitrate at 25°C containing 10, 20 and 30 mass % of nitric acid has been studied by the isothermal method. The Schreinemakers method has been used to establish the composition of the solid phases, which has been confirmed by crystallographic and thermographic studies. Data are presented on the viscosity

  14. Extraction of nitric acid, uranyl nitrate, and bismuth nitrate from aqueous nitric acid solutions with CMPO

    Microsoft Academic Search

    1995-01-01

    DOE sponsored development of the transuranium extraction (TRUEX) process for removing actinides from radioactive wastes. The solvent is a mixture of CMPO and TBP. Since the extraction characteristics of CMPO are not as well understood as those of TBP, the extraction of nitric acid, uranyl nitrate, and bismuth nitrate with CMPO (dissolved in n-dodecane) were studied. Results indicate that CMPO

  15. Feedback Regulation of Nitrate Influx in Barley Roots by Nitrate, Nitrite, and Ammonium.

    PubMed Central

    King, B. J.; Siddiqi, M. Y.; Ruth, T. J.; Warner, R. L.; Glass, ADM.

    1993-01-01

    The short-lived radiotracer 13N was used to study feedback regulation of nitrate influx through the inducible high-affinity transport system of barley (Hordeum vulgare L. cv Steptoe) roots. Both wild-type plants and the mutant line Az12:Az70 (genotype nar1a;nar7w), which is deficient in the NADH-specific and NAD(P)H-bispecific nitrate reductases (R.L. Warner, R.C. Huffaker [1989] Plant Physiol 91: 947-953) showed strong feedback inhibition of nitrate influx within approximately 5 d of exposure to 100 fmu]M nitrate. The result with the mutant, in which the flux of nitrogen into reduced products is greatly reduced, indicated that nitrate itself was capable of exercising feedback regulation upon its own influx. This conclusion was supported by the observation that feedback in wild-type plants occurred in both the presence and absence of L-methionine sulfoximine, an inhibitor of ammonium assimilation. Nitrite and ammonium were also found to be capable of exerting feedback inhibition upon nitrate influx, although it was not determined whether these ions themselves or subsequent metabolites were responsible for the effect. It is suggested that feed-back regulation of nitrate influx is potentially mediated through several nitrogen pools, including that of nitrate itself. PMID:12231904

  16. 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

  17. 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

  18. Selective nitrations. Volume 2: The laser-induced nitration of three cycloalkanes

    Microsoft Academic Search

    Ann E. Stanley; Judith M. Bonicamp; Susan E. Godbey; Larry M. Ludwick

    1993-01-01

    The army uses nitrated compounds as explosives and propellants. There is a special need for propellants with the chemical composition necessary to burn exactly with high energy production, but with a minimum of side products which create smoke. Laser-induced chemistry possesses the potential to drive some reactions in an efficient and selective manner, and may be useful in driving nitration

  19. Discrepancy between nitrate reduction rates in intact leaves and nitrate reductase activity in leaf extracts: What limits nitrate reduction in situ?

    Microsoft Academic Search

    Werner M. Kaiser; Andrea Kandlbinder; Maria Stoimenova; Johanna Glaab

    2000-01-01

    .   Nitrate reductase (NR) activity in spinach leaf extracts prepared in the presence of a protein phosphatase inhibitor (50??M\\u000a cantharidine) was measured in the presence of Mg2+ (NRact) or EDTA (NRmax), under substrate saturation. These in-vitro activities were compared with nitrate reduction rates\\u000a in leaves from nitrate-sufficient plants. Spinach leaves containing up to 60??mol nitrate per g fresh weight were

  20. Processing and properties of zirconium diboride-based composites

    Microsoft Academic Search

    F Monteverde; A Bellosi; S Guicciardi

    2002-01-01

    Two zirconium diboride-base composites were produced and characterised. The chosen starting compositions were: 55 wt.% ZrB2+41 wt.%TiB2+4 wt.% Ni and 83 wt.% ZrB2+13 wt.% B4C+4 wt.% Ni. The microstructure and properties of these composites were compared to those of a monolithic ZrB2+4 wt.% Ni material. In all cases, metallic Ni as the sintering aid promoted the formation of the liquid

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

    SciTech Connect

    Hollis, Kendall J [Los Alamos National Laboratory; Pena, Maria I [Los Alamos National Laboratory

    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.

  2. Regulation of Nitrate Reductase in Excised Barley Roots 1

    PubMed Central

    Smith, F. W.; Thompson, John F.

    1971-01-01

    When excised barley roots (Hordeum distichum L.) are appropriately pretreated, the level of nitrate reductase in the roots increases upon exposure to nitrate. Relatively low levels of nitrate (10 ?m) gave maximum induction of nitrate reductase. This increase was inhibited by inhibitors of protein and RNA synthesis, indicating that de novo protein synthesis is probably involved. Induction of nitrate reductase by nitrate is partially prevented by the inclusion of ammonium, an eventual product of nitrate reduction, in the incubation medium. Under the experimental conditions used, ammonium did not inhibit the uptake of nitrate by excised barley roots. It is concluded, therefore, that ammonium, or a product of ammonium metabolism, has a direct effect on the synthesis of nitrate reductase in this tissue. PMID:16657766

  3. Establishing a Multi-Spatial Wireless Sensor Network to Monitor Nitrate Concentrations in Soil Moisture

    E-print Network

    2004-01-01

    Wireless Sensor Network to Monitor Nitrate Concentrations inSensors for measuring temperature, precipitation, moisture, nitrate.sensors to measure temperature, precipitation, and soil moisture and nitrates.

  4. Proteomic Approaches to Analyze Protein Tyrosine Nitration

    PubMed Central

    Feeney, Maria B.

    2013-01-01

    Abstract Significance: The conversion of protein-bound Tyr residues to 3-nitrotyrosine (3NY) can occur during nitrative stress and has been correlated to aging and many disease states. Proteomic analysis of this post-translational modification, using mass spectrometry-based techniques, is crucial for understanding its potential role in pathological and physiological processes. Recent Advances: To overcome some of the disadvantages inherent to well-established nitroproteomic methods using anti-3NY antibodies and gel-based separations, methods involving multidimensional chromatography, precursor ion scanning, and/or chemical derivatization have emerged for both identification and quantitation of protein nitration sites. A few of these methods have successfully detected endogenous 3NY modifications from biological samples. Critical Issues: While model systems often show promising results, identification of endogenous 3NY modifications remains largely elusive. The frequently low abundance of nitrated proteins in vivo, even under inflammatory conditions, is especially challenging, and sample loss due to derivatization and cleaning may become significant. Future Directions: Continued efforts to avoid interference from non-nitrated peptides without sacrificing recovery of nitrated peptides are needed. Quantitative methods are emerging and are crucial for identifying endogenous modifications that may have significant biological impacts. Antioxid. Redox Signal. 19, 1247–1256. PMID:23157221

  5. Vulnerability of streams to legacy nitrate sources

    USGS Publications Warehouse

    Tesoriero, Anthony J.; Du?, John H.; Saad, David A.; Spahr, Norman E.; Wolock, David M.

    2013-01-01

    The influence of hydrogeologic setting on the susceptibility of streams to legacy nitrate was examined at seven study sites having a wide range of base flow index (BFI) values. BFI is the ratio of base flow to total streamflow volume. The portion of annual stream nitrate loads from base flow was strongly correlated with BFI. Furthermore, dissolved oxygen concentrations in streambed pore water were significantly higher in high BFI watersheds than in low BFI watersheds suggesting that geochemical conditions favor nitrate transport through the bed when BFI is high. Results from a groundwater-surface water interaction study at a high BFI watershed indicate that decades old nitrate-laden water is discharging to this stream. These findings indicate that high nitrate levels in this stream may be sustained for decades to come regardless of current practices. It is hypothesized that a first approximation of stream vulnerability to legacy nutrients may be made by geospatial analysis of watersheds with high nitrogen inputs and a strong connection to groundwater (e.g., high BFI).

  6. Nitrate transceptor(s) in plants.

    PubMed

    Gojon, Alain; Krouk, Gabriel; Perrine-Walker, Francine; Laugier, Edith

    2011-04-01

    The availability of mineral nutrients in the soil dramatically fluctuates in both time and space. In order to optimize their nutrition, plants need efficient sensing systems that rapidly signal the local external concentrations of the individual nutrients. Until recently, the most upstream actors of the nutrient signalling pathways, i.e. the sensors/receptors that perceive the extracellular nutrients, were unknown. In Arabidopsis, increasing evidence suggests that, for nitrate, the main nitrogen source for most plant species, a major sensor is the NRT1.1 nitrate transporter, also contributing to nitrate uptake by the roots. Membrane proteins that fulfil a dual nutrient transport/signalling function have been described in yeast and animals, and are called 'transceptors'. This review aims to illustrate the nutrient transceptor concept in plants by presenting the current evidence indicating that NRT1.1 is a representative of this class of protein. The various facets, as well as the mechanisms of nitrate sensing by NRT1.1 are considered, and the possible occurrence of other nitrate transceptors is discussed. PMID:21239382

  7. Vulnerability of streams to legacy nitrate sources.

    PubMed

    Tesoriero, Anthony J; Duff, John H; Saad, David A; Spahr, Norman E; Wolock, David M

    2013-04-16

    The influence of hydrogeologic setting on the susceptibility of streams to legacy nitrate was examined at seven study sites having a wide range of base flow index (BFI) values. BFI is the ratio of base flow to total streamflow volume. The portion of annual stream nitrate loads from base flow was strongly correlated with BFI. Furthermore, dissolved oxygen concentrations in streambed pore water were significantly higher in high BFI watersheds than in low BFI watersheds suggesting that geochemical conditions favor nitrate transport through the bed when BFI is high. Results from a groundwater-surface water interaction study at a high BFI watershed indicate that decades old nitrate-laden water is discharging to this stream. These findings indicate that high nitrate levels in this stream may be sustained for decades to come regardless of current practices. It is hypothesized that a first approximation of stream vulnerability to legacy nutrients may be made by geospatial analysis of watersheds with high nitrogen inputs and a strong connection to groundwater (e.g., high BFI). PMID:23530900

  8. Measuring Nitrates and Their Effect on Water Quality

    NSDL National Science Digital Library

    Larry Johnson

    This module on measuring nitrates and their effects on water quality is from a larger series on water quality investigations. It provides background information on nitrates and how it affects water quality. It also contains both a pre-test and post-test, a laboratory investigation, and a self-study game. The purpose of the site is to help students understand the sources of nitrates and the role that nitrates play in an ecosystem, describe the effects of excess nitrates on water quality and human health, and teach students how to measure, graph, and interpret the direct and indirect effects of nitrates on fish.

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

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

    The optimization of zirconium-based alloys used for nuclear fuel cladding aims 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 investigate the effects of alloying elements, microstructure and corrosion kinetics on hydrogen uptake. To measure hydrogen concentrations in zirconium alloys two techniques have been used: a destructive technique, Vacuum Hot Extraction, and a non-destructive one, Cold Neutron Prompt Gamma Activation Analysis. The results of both techniques show that hydrogen pickup fraction varies significantly with exposure time and between alloys. A possible interpretation of the results is that hydrogen pickup results from the need to balance charge. That is, the pickup of hydrogen shows an inverse relationship to oxidation kinetics, indicating that, if transport of charged species is rate limiting, oxide transport properties such as oxide electronic conductivity play a key role in the hydrogen pickup mechanism. Alloying elements (either in solid solution or in precipitates) would therefore impact the hydrogen pickup fraction by affecting charge transport.

  11. Dispersion type zirconium matrix fuels fabricated by capillary impregnation method

    NASA Astrophysics Data System (ADS)

    Savchenko, A.; Konovalov, I.; Vatulin, A.; Morozov, A.; Orlov, V.; Uferov, O.; Ershov, S.; Laushkin, A.; Kulakov, G.; Maranchak, S.; Petrova, Z.

    2007-05-01

    Several novel dispersion fuel compositions with a high uranium content fuel (U9Mo, U5Zr5Nb, U 3Si) and a zirconium alloy matrix with low melting point (1063-1133 K) have been developed at A.A. Bochvar Institute using a capillary impregnation fabrication method. The capillary impregnation method introduces fuel granules and granules of a zirconium alloy into a fuel element followed by a short-term anneal at a temperature above the melting temperature of alloy. The alloy melts down and under capillary forces moves into the joints between the fuel element components to form metallurgical bonds. The volume ratios between the components are: 55-65% fuel, 10-20% matrix, and 15-30% pores. Fuel elements produced by capillary impregnation method have a high uranium content (9-10 g cm -3) and a high thermal conductivity (18-22 W m -1 K -1), which, when used as PWR or BWR fuels allow the fuel temperature to be lowered to 723-773 K. They also feature porosity to accommodate swelling. The metallurgical fuel-cladding bond makes the fuel elements serviceable in power transients. The primary advantages for PWR, BWR and CANDU use of these fuels elements, would be the high uranium content, low fuel temperature and serviceability under transient conditions. Consideration is given to their applicability in Floating Nuclear Power Plants (FNPP) as well as for the feasibility of burning civil and weapon grade plutonium.

  12. Wear Analysis in THA Utilizing Oxidized Zirconium and Crosslinked Polyethylene

    PubMed Central

    Garvin, Kevin L.; Mangla, Jimmi; Murdoch, Nathan; Martell, John M.

    2008-01-01

    Oxidized zirconium, a material with a ceramic surface on a metal substrate, and highly cross-linked polyethylene are two materials developed to reduce wear. We measured in vivo femoral head penetration in patients with these advanced bearings. We hypothesized the linear wear rates would be lower than those published for cobalt-chrome and standard polyethylene. We retrospectively reviewed a select series of 56 THAs in a relatively young, active patient population utilizing oxidized zirconium femoral heads and highly cross-linked polyethylene acetabular liners. Femoral head penetration was determined using the Martell computerized edge-detection method. All patients were available for 2-year clinical and radiographic followup. True linear wear was 4 ?m/year (95% confidence intervals, ± 59 ?m/year). The early wear rates in this cohort of relatively young, active patients were low and we believe justify the continued study of these alternative bearing surfaces. Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18946711

  13. Solidification of a Vacuum Arc-Remelted Zirconium Ingot

    NASA Astrophysics Data System (ADS)

    Revil-Baudard, Matthieu; Jardy, Alain; Combeau, Hervé; Leclerc, Faustine; Rebeyrolle, Véronique

    2013-10-01

    As the quality of vacuum arc-remelted (VAR) zirconium ingots is directly linked to their chemical homogeneity and their metallurgical structure after solidification, it is important to predictively relate these factors to the operating conditions. Therefore, a detailed modeling study of the solidification process during VAR has been undertaken. To this purpose, the numerical macromodel SOLAR has been used. Assuming axisymmetrical geometry, this model is based on the solution of the coupled transient heat, momentum, and solute transport equations, under turbulent flow conditions during the remelting, hot-topping, and cooling of a cylindrical ingot. The actual operating parameters are defined as inputs for the model. Each of them, mainly the melting current sequence, melting rate sequence, and stirring parameters (current and period), is allowed to vary with time. Solidification mechanisms recently implemented in the model include a full coupling between energy and solute transport in the mushy zone. This modeling can be applied to actual multicomponent alloys. In this article, the macrosegregation induced by solidification in a zirconium alloy ingot is investigated. In order to validate the model results, a full-scale homogeneous Zy4 electrode has been remelted, and the resulted ingot has been analyzed. The model results show a general good agreement with the chemistry analyses, as soon as thermosolutal convection is accounted for to simulate accurately the interdendritic fluid flow in the central part of the ingot.

  14. Nitrate isotope fractionations during biological nitrate reduction: Insights from first principles theoretical modeling

    NASA Astrophysics Data System (ADS)

    Guo, W.; Granger, J.; Sigman, D. M.

    2010-12-01

    Coupled fractionations of N and O isotopes during biological nitrate reduction provide important constraints on the marine nitrogen cycle at present and in the geologic past. Recent laboratory experiments with mono-cultures of nitrate-assimilative algae and plankton, and denitrifying bacteria demonstrate that N and O isotopic compositions of the residual nitrate co-vary linearly with a constant ratio (i.e., ??18O: ??15N) of ~1 or ~0.6 [1]. These systematic variations have been inferred to derive from the kinetic isotope fractionations associated with nitrate reductases. The isotope fractionation mechanisms at the enzymatic level, however, remain elusive. Here we present models of isotope fractionations accompanying the nitrate reduction (NO3-?NO2-) by three functional types of nitrate reductases, using techniques from ab initio, transition state and statistical thermodynamic theory. We consider three types of nitrate reductases: eukNR (eukaryotic assimilatory nitrate reductase), NAR (prokaryotic respiratory nitrate reductase) and Nap (prokaryotic periplasmic nitrate reductase). All are penta- or hexa-coordinated molybdo-enzymes, but bear considerable differences in protein geometry among functional types. Our models, based on the simplified structures of their active sites, predict N and O isotope effects (15? and 18?) ranging from 32.7 to 36.6‰ and from 33.5 to 34.8‰, respectively, at 300K with 18?:15? ratios of 0.9-1.1. The predicted amplitudes of N and O isotope fractionations are in the range measured for eukNR in vitro (~27‰, Karsh et al. in prep), and also correspond to the upper amplitudes observed for denitrifiers in vivo (~25‰, [1]). Moreover, the computed 18?:15? ratios corroborate the consistent relationships of ~1 observed experimentally for eukNR and the respiratory NAR. These findings indicate the enzymatic reduction is likely the rate-limiting step in most biological nitrate reductions. In addition, the predicted similarity of 18?:15? ratios among different nitrate reductases suggests that the nitrate isotope fractionations by nitrate reductases are governed by the kinetics of the O-N bond cleavage, which incurs negligible differences from variations in surrounding moieties at the active sites. However, our model similarly predicts a 15? of 36.6‰ and 18?:15? of 0.9 for the auxiliary Nap, although it exhibits a 15? of ~15‰ and 18?:15? of ~0.6 in vivo [1]. This discrepancy is suspected to arise from slower binding and release of NO3- from Nap, which could be partially rate-determining in this enzymatic catalysis, or from the assumptions of our modeled enzyme structures. By extending our above models to include the multiply-substituted (clumped) isotopologues, we predict that isotope fractionations during biological nitrate reduction decrease the proportion of 15N-18O bonds in the residual nitrate relative to their expected equilibrium abundances (~0.02‰ decrease for every 1‰ kinetic enrichment in nitrate ?15N). Future quantification of 15N-18O clumped isotope anomalies in natural nitrate may provide additional constraints on the nitrogen cycle in the ocean. Reference: [1] Granger et al. (2010) GCA, 74: 1030-1040.

  15. [Nitrate contents in autumn vegetables and assessment of nitrate intake in Shanghai].

    PubMed

    Guo, Kai-Xiu; Yao, Chun-Xia; Chen, Yi; Yang, Ye-Feng; Lu, Li-Min

    2011-04-01

    To analyze and assess the nitrate contents in Autumn vegetables and nitrate intake in Shanghai resident 25 groups and 439 various vegetables were collected and analyzed from the green houses and outdoors in Songjiang, Fengxian, Jinshan and Pudong of Shanghai during Sep.-Nov., 2009. Nitrate contents were analyzed by UV-spectrophotometer. The results showed that the prevalence of severe contamination was 41.46%, the prevalence of heavy and medium contamination was 30.53%, the prevalence of mild contamination was 28.02%; the content of nitrate in vegetables was in the following descent order: leafy vegetables, root and stem vegetables, melons, egg plants, beans, the nitrate contents in different species differed greatly; the nitrate contents in leafy, root and stem vegetables with green-house planting were less than that of outdoor planting in Fengxian and Songjiang except Pudong and Jinshan. According to the assessment of nitrate intake, the average daily intake of local resident is 445.22 mg which exceeds ADI 38.42%, so limited standard and control are urgently needed. PMID:21717766

  16. Biodegradation of Glycidol and Glycidyl Nitrate †

    PubMed Central

    Kaplan, David L.; Cornell, John H.; Kaplan, Arthur M.

    1982-01-01

    When calcium hydroxide is used to desensitize glycerol trinitrate (nitroglycerine)-containing waste streams, the epoxides glycidol and glycidyl nitrate are formed. The epoxide rings of both compounds are unstable to heat in aqueous solutions, and they open to form glycerol 1-mononitrate and presumably glycerol. These transformations were accelerated by microbial activity. Glycerol 1-mononitrate was slowly denitrated to form glycerol. Glycidol and glycidyl nitrate caused base-pair substitutions in the Ames test for mutagenicity, whereas glycerol 1-mononitrate tests were negative. PMID:16345917

  17. Nitrates and detinning in canned carrots 

    E-print Network

    Florine, Thomas Edward

    1968-01-01

    , green beans, sweet potatoes, and potatoes. A few other products have also exhibited the rapid detin- ning which occurs at a rate of five to ten times normal (8). With the rate of detinning at five to ten times normal, the product will not store for a... at a rapid rate, were traced back to farms which had applied high levels of nitrate nitrogen fertilizer to the crops during the growing season (8). Above normal levels of nitrates in the product at time of canning were suspected of being the agent...

  18. 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.

  19. Histopathological and microanalytical study of zirconium dioxide and barium sulphate in bone cement.

    PubMed Central

    Keen, C. E.; Philip, G.; Brady, K.; Spencer, J. D.; Levison, D. A.

    1992-01-01

    AIMS: To report the appearances of zirconium dioxide and barium sulphate in interface membranes, synovium, and other tissues around joint prostheses. METHODS: Histological sections from 23 specimens were reviewed by light microscopy and polarisation. Scanning electron microscopy and x ray microanalysis were performed on routinely processed paraffin wax sections. RESULTS: Polyethylene, metals, and polymethylmethacrylate cement debris were easily recognisable. Almost all the cement remnants contained either zirconium dioxide or barium sulphate, confirmed by microanalysis. The contrast media had characteristic light microscopic appearances. Zirconium was identified in macrophages away from cement remnants. CONCLUSION: The presence of radiographic contrast media in tissues around prosthetic joints is common but not widely recognised. Images PMID:1452794

  20. Mammalian nitrate biosynthesis: mouse macrophages produce nitrite and nitrate in response to Escherichia coli lipopolysaccharide

    Microsoft Academic Search

    D. J. Stuehr; M. A. Marletta

    1985-01-01

    Escherichia coli lipopolysaccharide (LPS)-induced nitrate biosynthesis was studied in LPS-sensitive C3H\\/He and LPS-resistant C3H\\/HeJ mice. Intraperitoneal injection of 15 ..mu..g of LPS led to a temporary 5- to 6-fold increase in blood nitrate concentration in the C3H\\/He strain. Levels of nitrate excreted in the urine were also increased. In contrast, no increase was observed in the C3H\\/HeJ strain with LPS

  1. Poly(methyl methacrylate)-cellulose nitrate copolymers. I. Preparation

    SciTech Connect

    Badran, B.M.; Sherif, S.; Abu-Sedira, A.A.

    1981-03-01

    Poly(methyl methacrylate)-cellulose nitrate copolymers were prepared in the form of rods and sheets by bulk polymerization using benzoyl peroxide as initiator. Suspension polymerization did not succeed in preparing poly(methyl methacrylate)-cellulose nitrate copolymers, especially when cellulose nitrate of 11.4% nitrogen content was used. The parameters such as cellulose nitrate concentration, nitrogen content of cellulose nitrate, the amount of initiator and the reaction time, and the temperature are discussed. The prepared copolymers were irradiated for specified periods of up to 11.83 Mrad. It was found that poly(methyl methacrylate)-cellulose nitrate copolymers did not dissolve in any conventional solvent, but they swelled. Swelling decreases with increasing cellulose nitrate concentrations, nitrogen content of cellulose nitrate, and irradiation dose, indicating the crosslinked structure of the prepared copolymers.

  2. Investigation of desert subsoil nitrate in Northeastern Badia of Jordan.

    PubMed

    Al-Taani, Ahmed A; Al-Qudah, Khaldoun A

    2013-01-01

    High levels of naturally occurring nitrate were observed under desert pavement surfaces in NE Badia of Jordan. The subsoil nitrate inventory varies from about 24,351 to 28,853 kg NO(3)(-)/ha to a depth of 60 cm which is more than two times greater than nitrate in nonpavement soils, although both soils occurred within similar landscape and microclimate conditions. The results indicated that pavement particle size and cover percent are the primary factors contributing to the observed variations in nitrate accumulation. Desert pavement soils fully covered with fine clasts showed higher nitrate concentrations compared to soils moderately covered with coarse-grained pavements. The results also showed that high levels of nitrate were generally reached between 20 and 30 cm depth before the concentrations decreased. Chloride showed distribution profiles similar to those of nitrate. No observable difference was observed in nitrate level under desert pavement with abundant lichens compared to non-lichen pavement surface. PMID:23178770

  3. Reduction of nitrate by bimetallic Fe\\/Ni nanoparticles

    Microsoft Academic Search

    Haiyan Kang; Zongming Xiu; Jiawei Chen; Wenping Cao; Yifei Guo; Tielong Li; Zhaohui Jin

    2012-01-01

    Bimetallic Fe\\/Ni nanoparticles were synthesized and their nitrate reduction capacity was studied. Nitrate (354 mg L, equal to 5.71 mmol L) reduction was performed using Fe\\/Ni nanoparticles with various Ni contents (1.0, 5.0, 10 and 20%) in an unbuffered condition. Optimum nitrate reduction rate () was obtained with 5.0% nano-scale Fe\\/Ni, while only 25% nitrate () was transformed by nano-scale Fe within the same

  4. Inorganic nitrate and the cardiovascular system

    Microsoft Academic Search

    V. Kapil; A. J. Webb; A. Ahluwalia

    2010-01-01

    Fruit and vegetable-rich diets reduce blood pressure and risk of ischaemic stroke and ischaemic heart disease. While the cardioprotective effects of a fruit and vegetable-rich diet are unequivocal, the exact mechanisms of this effect remain uncertain. Recent evidence has highlighted the possibility that dietary nitrate, an inorganic anion found in large quantities in vegetables (particularly green leafy vegetables), may have

  5. Nitrates in Vegetables Produced in Greece

    Microsoft Academic Search

    Anastasios S. Siomos; Constantinos C. Dogras

    2000-01-01

    The nitrate content of spinach, leaf and romaine lettuce, endive, parsley, dill, celery, beet leaves and roots, turnip, radish, carrot, white and red cabbage, broccoli, cauliflower, Brussels sprouts, leek, green and dry onion, cucumber, tomato, eggplant, summer squash, snap bean, potato, and bell pepper obtained regularly from the Wholesale Vegetable Market of Thessaloniki, Central Macedonia, Greece was determined during the

  6. A Proteomic Study of Protein Tyrosine Nitration

    E-print Network

    Hong, Sung Jung

    2008-08-28

    from Sigma-Aldrich Chemical Company (St.Louis, MO), and was nitrated with peroxynitrite (ONOO-) synthesized in the laboratory according to Beckman et. al. (12). Tris/HCl, MgCl2 sodium phosphate diabasic (Na2HPO4), guanidine-HCl and sequencing grade...

  7. Iron, nitrate uptake by phytoplankton, and mermaids

    Microsoft Academic Search

    Karl Banse

    1991-01-01

    The critque by Martin et al. (this issue) of my recalculation of rates of nitrate uptake, and hence of algal division, from the Gulf of Alaska is shown to be incorrect. Neither can iron deficiency, if any, be shown to be connected with the demise of mermen and mermaids, although for different reasons.

  8. Evaluation of ferrocyanide\\/nitrate explosive hazard

    Microsoft Academic Search

    Cady

    1992-01-01

    Los Alamos National Laboratory agreed to assist Pacific Northwest Laboratory in the Ferrocyanide Safety Evaluation Program by helping to evaluate the explosive hazard of several mixtures of simulated ferrocyanide waste-tank sludge containing sodium nitrite and sodium nitrate. This report is an evaluation of the small-scale safety tests used to assess the safety of these materials from an explosive point of

  9. Assimilatory Nitrate Reduction in Hansenula polymorpha

    NASA Astrophysics Data System (ADS)

    Rossi, Beatrice; Berardi, Enrico

    In the last decade, the yeast Hansenula polymorpha (syn.: Pichia angusta) has become an excellent experimental model for genetic and molecular investigations of nitrate assimilation, a subject traditionally investigated in plants, filamentous fungi and bacteria. Among other advantages, H. polymorpha offers classical and molecular genetic tools, as well as the availability of genomic sequence data.

  10. 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.

  11. 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…

  12. 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

  13. 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...

  14. Physiologie vgtale Mesure de l'activit nitrate rductase

    E-print Network

    Paris-Sud XI, Université de

    Physiologie végétale Mesure de l'activité nitrate réductase durant le cycle cultural du soja, assimilation du nitrate et fixation de l'azote de l'air, ont été étudiées chez le soja (cv Hodgson), inoculé avec Bradyrhizobium japonicum USDA 138. L'évolution des 2 activités enzymatiques, nitrate réductase et

  15. 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...

  16. 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...

  17. 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

  18. Original article Ionic adsorption of ammonium and nitrate on some

    E-print Network

    Paris-Sud XI, Université de

    Original article Ionic adsorption of ammonium and nitrate on some animal litters and their role -- Two experiments were carried out to determine the adsorption of ammonium and nitrate on litters (Exp added to the tubes which were incubated for 24 h. Ammonium and nitrate concentrations, and pH, were

  19. 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

  20. Article original Teneur en nitrate du lait. Relation

    E-print Network

    Paris-Sud XI, Université de

    Article original Teneur en nitrate du lait. Relation avec sa concentration dans l'eau d ― La pollution par les nitrates des eaux superficielles et nappes phréatiques, conduit à une augmentation sensible de la teneur en nitrate de l'eau d'abreuvement des vaches laitières et il faut donc

  1. Waste Isolation Pilot Plant Nitrate Salt Bearing Waste Container

    E-print Network

    Napp, Nils

    Waste Isolation Pilot Plant Nitrate Salt Bearing Waste Container Isolation Plan Prepared. The Order, at paragraph 22, requires the Permittees to submit a WIPP Nitrate Salt Bearing Waste Container Isolation Plan (Plan) for identified nitrate salt bearing waste disposed in the Waste Isolation Pilot Plant

  2. Maximum rates of nitrate removal in a denitrification wall.

    PubMed

    Schipper, Louis A; Barkle, Gregory F; Vojvodic-Vukovic, Maja

    2005-01-01

    Denitrification walls are constructed by mixing a carbon source such as sawdust into soils through which ground water passes. These systems can reduce nitrate inputs to receiving waters by enhancing denitrification. Maximum rates of nitrate removal by denitrification need to be determined for design purposes. To determine maximum rates of nitrate removal we added excess nitrate (50 mg N L(-1)) to a trench up-gradient of a denitrification wall during a 9-d trial. Bromide (100 g L(-1)) was also added as a conservative tracer. Movement of nitrate and bromide was measured from shallow wells and soil samples were removed for measurements of denitrification, carbon availability, nitrate, and other microbial parameters. Rates of nitrate removal, determined from the ratio of NO3-N to Br and ground water flow, averaged 1.4 g N m(-3) of wall d(-1) and were markedly greater than denitrification rates determined using the acetylene block technique (average: 0.11 g N m(-3) of wall d(-1)). These nitrate removal rates were generally lower than reported in other denitrification walls. Denitrification rates increased when nitrate was added to the laboratory incubations, indicating that despite large nitrate inputs in the field, denitrification remained limited by nitrate. This limitation was partially attributed to nitrate predominantly moving through zones of greater hydraulic conductivity or in the mobile fraction of the ground water and slow diffusion to the immobile fraction where denitrifiers were active. PMID:15998848

  3. Carbonyl Alkyl Nitrates as Trace Constituents in Urban Air

    Microsoft Academic Search

    S. Woidich; A. Gruenert; K. Ballschmiter

    2003-01-01

    Organic nitrates, esters of nitric acid, significantly contribute to the entire pool of odd nitrogen (NOY) in the atmosphere. Organic nitrates are formed in NO rich air by degradation of alkanes and alkenes initiated by OH and NO3 radicals during daytime and nighttime, respectively. Bifunctional organonitrates like the alkyl dinitrates and hydroxy alkyl nitrates are formed primarily from alkenes. The

  4. ORIGINAL PAPER Nitrate reductase activity and nitrogen compounds in xylem

    E-print Network

    ORIGINAL PAPER Nitrate reductase activity and nitrogen compounds in xylem exudate of Juglans nigra is limited. We fertilized 1-year-old, half-sib black walnut (Juglans nigra L.) seedlings with ammonium (NH4 Nitrate Á Nitrate reductase Á Ammonium Á Xylem exudate Introduction Black walnut (Juglans nigra L.) is one

  5. Mechanism study of nitrate reduction by nano zero valent iron

    Microsoft Academic Search

    Yu-Hoon Hwang; Do-Gun Kim; Hang-Sik Shin

    2011-01-01

    This study investigates the fate of nitrogen species during nitrate reduction by nano-scale zero valent iron (NZVI) and related reaction mechanisms. The NZVI used for the experiments was prepared by chemical reduction without a stabilizing agent. NZVI has great ability to reduce nitrate. However, the question of what end-product results from nitrate reduction by NZVI has sparked controversy. Establishing nitrogen

  6. Thermal Dissociation Kinetics of Solid and Liquid Ammonium Nitrate

    E-print Network

    Utah, University of

    Thermal Dissociation Kinetics of Solid and Liquid Ammonium Nitrate Sergey Vyazovkin,* Jacalyn S and liquid ammonium nitrate. Model-fitting and model-free kinetic methods have been applied to the sets/vaporization. Introduction Ammonium nitrate (AN) finds a widespread applica- tion as both fertilizer and energetic material

  7. Maximum Rates of Nitrate Removal in a Denitrification Wall

    Microsoft Academic Search

    Louis A. Schipper; Gregory F. Barkle; Maja Vojvodic-Vukovic

    2005-01-01

    coarse sands with thin layers of silt and clay. We showed that mixing of aquifer material and sawdust under satu- 1 ). These nitrate removal rates the designers of such systems require information on were generally lower than reported in other denitrification walls. upperratesofnitrateremovalforawiderangeofground Denitrification rates increased when nitrate was added to the labora- water flow rates and nitrate loads.

  8. Nitrate loss and transformation in 2 vegetated headwater streams

    Microsoft Academic Search

    A. Bryce Cooper; James G. Cooke

    1984-01-01

    The processes of nitrate removal from the stream waters of 2 headwater catchments were studied. In study stretches where the stream channels were vegetated with thick mats of grass (Gly?ceria fluitans), nitrate removal processes were particularly active. In such grassed stream channels, c. 75% of the nitrate removal was attributable to plant uptake and the remainder to denitrifica?tion. Both of

  9. Gas pressure in sealed sample cans concentrated plutonium nitrate

    Microsoft Academic Search

    1953-01-01

    The objective of this work was to establish as fact that the predominant gas evolved from concentrated plutonium nitrate solutions is oxygen. Four sample cans containing plutonium nitrate at various concentrations were sealed using plug valves equipped with pressure gages. The results obtained showed that the gas evolved from concentrated plutonium nitrate solutions is predominately oxygen. It is believed that

  10. Selection of corrosion-resistant materials for use in molten nitrate salts

    SciTech Connect

    Tortorelli, P.F.; Bishop, P.S.; DiStefano, J.R.

    1989-10-01

    Investigations of the corrosion of various metals, alloys, and ceramics in high-temperature nitrate salt melts revealed that relatively few materials have acceptable compatibility in a 650{degrees}C, NaNO{sub 3}(-KNO{sub 3})-Na{sub 2}O{sub 2} environment that was chemically characteristic of the MOLTOX{trademark} chemical air separation process. Corrosion in these systems was controlled by the stabilities of the salt and solid-state surface oxides (whether they were ore-existing or formed upon exposure), the salt's oxide ion activity (strongly influenced by Na{sub 2}O{sub 2} additions), and the physical condition of the solid surfaces. In general, refractory/reactive metals and alloys (with the exception of zirconium and hafnium), cobalt, nickel, NiMo, TiAl, austenitic steel, and Ni-Cr-Fe alloys were found to corrode quite readily because of rapid oxidation and/or dissolution in the salt. 22 refs., 29 figs., 5 tabs.

  11. 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

  12. 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...

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

    E-print Network

    Parkison, Adam J

    2013-06-04

    The fundamental behavior underpinning a new processing concept was demonstrated which is capable of separating uranium from zirconium in U-Zr alloys through the formation and selective volatilization of their respective chlorides. Bench...

  14. 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...

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

    E-print Network

    Parkison, Adam J

    2013-06-04

    The fundamental behavior underpinning a new processing concept was demonstrated which is capable of separating uranium from zirconium in U-Zr alloys through the formation and selective volatilization of their respective chlorides. Bench...

  16. Methods for Investigating Gas Bubble Formation in Uranium-Zirconium Alloys 

    E-print Network

    Mews, Kathryn Ann Wright

    2013-05-06

    Uranium-zirconium alloy nuclear fuels have many advantages as compared with ceramic fuels, especially for fast reactor systems. However, metallic fuels aren’t currently used in commercial power production due in part to issues with fuel swelling...

  17. Hot Extrusion of Alpha Phase Uranium-Zirconium Alloys for TRU Burning Fast Reactors 

    E-print Network

    Hausaman, Jeffrey Stephen

    2012-02-14

    ; initial trials demonstrated significant losses during the casting process. A low temperature hot extrusion process was explored as a potential method to fabricate uranium-zirconium fuel alloys containing the TRU isotopes. The advantage of extrusion...

  18. 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...

  19. Effects of cold work and niobium on the blistering of zirconium by helium atoms

    NASA Astrophysics Data System (ADS)

    Zee, R. H.; Watters, J. F.

    1984-05-01

    Zr-2.5 wt% Nb and high purity zirconium, in either the fully annealed or 40% cold-worked conditions, were irradiated with 50 keV helium ions at temperatures between 100 K and 773 K to doses up to 2 × 10 22 ions/m 2. Above 300 K, blisters were not observed in annealed zirconium whereas at lower temperatures, extensive surface damage was produced. In Zr-2.5 wt% Nb, blisters were found in both the annealed and cold-worked alloys at all temperatures. The blistering behaviour in zirconium is related to the trapping of the implanted helium ions and the mechanical properties of these materials. Two zirconium single crystals were irradiated at 573 K and 773 K for comparison. Extensive blistering was observed in both single crystals even though no surface damage was found in the polycrystalline material irradiated under the same conditions.

  20. Formation of Tetrafluorobenzyne by -Fluoride Elimination in Zirconium-Perfluorophenyl Complexes

    E-print Network

    Jones, William D.

    5)F.4,5 In the zirconium system, some of the tetrafluorobenzyne was trapped using durene to give a Diels-Alder adduct. In the absence of durene, tetrafluorobenzyne formed adducts with the THF solvent.5

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

    E-print Network

    Mews, Paul Aaron

    2009-05-15

    wt% Re, 3) a rhenium-zirconium intermetallic, 4) another Fe-Zr intermetallic with very little Re, and 5) a Fe-Re intermetallic. Potentiostatic and potentiodynamic electrochemical tests were performed using sulfuric acid to evaluate the corrosion...

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

    SciTech Connect

    Vidal, E.E.; Taylor, P.R.; Manrique, M. [Univ. of Idaho, Moscow, ID (United States)

    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.

  3. The nitrate time bomb: a numerical way to investigate nitrate storage and lag time in the unsaturated zone.

    PubMed

    Wang, L; Butcher, A S; Stuart, M E; Gooddy, D C; Bloomfield, J P

    2013-10-01

    Nitrate pollution in groundwater, which is mainly from agricultural activities, remains an international problem. It threatens the environment, economics and human health. There is a rising trend in nitrate concentrations in many UK groundwater bodies. Research has shown it can take decades for leached nitrate from the soil to discharge into groundwater and surface water due to the 'store' of nitrate and its potentially long travel time in the unsaturated and saturated zones. However, this time lag is rarely considered in current water nitrate management and policy development. The aim of this study was to develop a catchment-scale integrated numerical method to investigate the nitrate lag time in the groundwater system, and the Eden Valley, UK, was selected as a case study area. The method involves three models, namely the nitrate time bomb-a process-based model to simulate the nitrate transport in the unsaturated zone (USZ), GISGroundwater--a GISGroundwater flow model, and N-FM--a model to simulate the nitrate transport in the saturated zone. This study answers the scientific questions of when the nitrate currently in the groundwater was loaded into the unsaturated zones and eventually reached the water table; is the rising groundwater nitrate concentration in the study area caused by historic nitrate load; what caused the uneven distribution of groundwater nitrate concentration in the study area; and whether the historic peak nitrate loading has reached the water table in the area. The groundwater nitrate in the area was mainly from the 1980s to 2000s, whilst the groundwater nitrate in most of the source protection zones leached into the system during 1940s-1970s; the large and spatially variable thickness of the USZ is one of the major reasons for unevenly distributed groundwater nitrate concentrations in the study area; the peak nitrate loading around 1983 has affected most of the study area. For areas around the Bowscar, Beacon Edge, Low Plains, Nord Vue, Dale Springs, Gamblesby, Bankwood Springs, and Cliburn, the peak nitrate loading will arrive at the water table in the next 34 years; statistical analysis shows that 8.7 % of the Penrith Sandstone and 7.3 % of the St Bees Sandstone have not been affected by peak nitrate. This research can improve the scientific understanding of nitrate processes in the groundwater system and support the effective management of groundwater nitrate pollution for the study area. With a limited number of parameters, the method and models developed in this study are readily transferable to other areas. PMID:23801341

  4. Extraction of REE(III) Nitrates with Polymer-Supported Trialkylmethylammonium Nitrate

    Microsoft Academic Search

    A. K. Pyartman; V. A. Keskinov; M. A. Mikhailenko; N. V. Nikitin; V. V. Lishchuk

    2004-01-01

    Extraction of La, Ce, Pr, Nd, Sm, and Y(III) nitrates with polymer-supported trialkylmethylammonium nitrate (Aliquat-336) in the presence 1-5 M NaNO3 in the aqueous phase is studied. The extraction isotherms are described taking into account formation of (R4N)2[Ln(NO3)5] in the extractant phase. The extraction constants decrease from La to Sm. The extraction constant of Y(III) is considerably lower than those

  5. Solid state phase transition and vapor pressure studies in ammonium nitrate-potassium nitrate binary system

    Microsoft Academic Search

    Wen-Ming Chien

    2003-01-01

    The solid-state phase transitions in ammonium nitrate (NH4NO 3) and potassium nitrate (KNO3) solid solutions and the equilibrium NH4NO3-KNO3 (AN-KN) phase diagram have been determined. The phase transitions and phase diagram were determined by using the differential scanning calorimetry (DSC) and high temperature X-ray diffractometry. Samples of several different compositions were made for these analyses in a special \\

  6. Mammalian nitrate biosynthesis: mouse macrophages produce nitrite and nitrate in response to Escherichia coli lipopolysaccharide

    SciTech Connect

    Stuehr, D.J.; Marletta, M.A.

    1985-11-01

    Escherichia coli lipopolysaccharide (LPS)-induced nitrate biosynthesis was studied in LPS-sensitive C3H/He and LPS-resistant C3H/HeJ mice. Intraperitoneal injection of 15 ..mu..g of LPS led to a temporary 5- to 6-fold increase in blood nitrate concentration in the C3H/He strain. Levels of nitrate excreted in the urine were also increased. In contrast, no increase was observed in the C3H/HeJ strain with LPS injections up to 175 ..mu..g. Furthermore, thioglycolate-elicited peritoneal macrophages from C3H/He, but not from C3H/HeJ mice, produced nitrite (60%) and nitrate (40%) when cultured with LPS (10 ..mu..g/ml). T-lymphocyte addition/depletion experiments showed the presence of T cells enhanced this response. However, LPS did not cause nitrite or nitrate production in cultures of spleen lymphocytes from either strain. LPS-induced nitrate synthesis was also observed with nude mice and CBA/N mice, indicating that neither functional T lymphocytes nor LPS-responsive B lymphocytes were required for the response in vivo. This was consistent with the in vitro results showing macrophages alone were competent. Mycobacterium bovis infection of C3H/He and C3H/HeJ mice resulted in a large increase in nitrate production over the course of the infection for both strains, suggesting T-lymphocyte-mediated activation of macrophages as a potent stimulus for nitrate biosynthesis. The synthesis of nitrite is significant in that it can directly participate in the endogenous formation of nitrosamines and may also be involved in some aspect of the chemistry of cytotoxicity.

  7. MICHIGAN'S SOIL NITRATE TEST FOR CORN MSU SOIL AND PLANT NUTRIENT LAB

    E-print Network

    Isaacs, Rufus

    nitrate contamination of groundwater. WHAT DOES THE TEST MEASURE A soil nitrate test measures the nitrateMICHIGAN'S SOIL NITRATE TEST FOR CORN MSU SOIL AND PLANT NUTRIENT LAB Michigan State University Extension Crop and Soil Sciences Department Michigan State University WHY TEST SOIL FOR NITRATES Nitrate

  8. Extraction of nitric acid, uranyl nitrate, and bismuth nitrate from aqueous nitric acid solutions with CMPO

    SciTech Connect

    Spencer, B.B.

    1995-08-01

    DOE sponsored development of the transuranium extraction (TRUEX) process for removing actinides from radioactive wastes. The solvent is a mixture of CMPO and TBP. Since the extraction characteristics of CMPO are not as well understood as those of TBP, the extraction of nitric acid, uranyl nitrate, and bismuth nitrate with CMPO (dissolved in n-dodecane) were studied. Results indicate that CMPO extracts nitric acid with a 1:1 stoichiometry; equilibrium constant is 2. 660{plus_minus}0.092 at 25 C, and extraction enthalpy is -5. 46{plus_minus}0.46 kcal/mol. Slope analysis indicates that uranyl nitrate extracts with a mixed equilibria of 1:1 and 2:1 stoichiometries in nearly equal proportion. Equil. constant of the 2: 1 extraction was 1.213 {times} 10{sup 6}{plus_minus}3.56 {times} 10{sup 4} at 25 C; reaction enthalpy was -9.610{plus_minus}0.594 kcal/mol. Nitration complexation constant is 8.412{plus_minus}0.579, with an enthalpy of -10.72{plus_minus}1.87 kcal/mol. Bismuth nitrate also extracts with a mixed equilibria of (perhaps) 1:1 and 2:1 stoichiometries. A 2:1 extraction equilibrium and a nitrate complexation adequately model the data. Kinetics and enthalpies were also measured.

  9. The manufacturing of zirconium metal powder by means of a high temperature plasma process

    Microsoft Academic Search

    J. L. Havenga; J. T. Nel

    2010-01-01

    Summary form only given. The most general application for high purity zirconium metal alloys is for cladding material for nuclear fuel assemblies in nuclear power plants. A process was developed to manufacture zirconium metal powder from ZrCl4 or ZrF4 with a high temperature DC non - transfer arc plasma. Mg or Ca metal was used as reductant. The reactants were

  10. AN EVALUATION OF THE PROPERTIES AND BEHAVIOR OF ZIRCONIUM-URANIUM ALLOYS

    Microsoft Academic Search

    A. A. ed

    1959-01-01

    Data from a survey of the literature and other available information on ;\\u000a zirconium--uranium alloys have been reviewed for the purpose of obtaining a ;\\u000a coherent picture of current knowledge about the properties and behavior of ;\\u000a zirconium--uranium alloys. The results of the survey were used to revise and ;\\u000a extend the presentation of material gathered earlier in a similar

  11. Actinide partitioning studies using dihexyl-N,N-diethycarbamolymehtyl phosphonate and dissolved zirconium calcine

    SciTech Connect

    Brewer, K.N.; Herbst, R.S.; Law, J.D.; Garn, T.G.; Tillotson, R.D.; Todd, T.A.

    1996-01-01

    A baseline flowsheet capable of partitioning the transuranic (TRU) elements from dissolved zirconium calcines has been developed. The goal of the TRU partitioning process is to remove the TRUs from solutions of dissolved zirconium calcines to below the 10 CFR 61.55 Class A waste limit of 10 nCi/g. Extraction, scrub, strip, and wash distribution coefficients for several elements, including the actinides, were measured in the laboratory by performing equal volume batch contacts. A solvent containing diheyl-N, N- diethylcarbamoylmethyl phosphonate (CMP), tributylphosphate (TBP), and a branched chain hydrocarbon as the diluent were used to develop this process. A non-radioactive zirconium pilot-plant calcine was spiked with the TRUs, U, Tc, or a radioactive isotope of zirconium to simulate the behavior of these elements in actual dissolved zirconium calcine feed. Distribution coefficient data obtained from laboratory testing were used to recommend: (1) solvent composition, (2) scrub solutions capable of selectively removing extracted zirconium while minimizing actinide recycle, (3) optimized strip solutions which quantitatively recover extracted actinides, and (4) feed adjustments necessary for flowsheet efficiency. Laboratory distribution coefficients were used in conjunction with the Generic TRUEX Model (GTM) to develop and recommend a flowsheet for testing in the 5.5-cm Centrifugal Contractor Mockup. GTM results indicate that the recommended flowsheet should remove the actinides from dissolved zirconium calcine feed to below the Class A waste limit of 10 nCi/g. Less than 0.01 wt% of the extracted zirconium will report to the high- activity waste (HAW) fraction using the 0.05 M H{sub 2}C{sub 2}O{sub 4} in 3.0 M HNO{sub 3} scrub, and greater than 99% of the extracted actinides are recovered with 0.001 M HEDPA.

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

    E-print Network

    Eichel, Daniel

    2013-06-17

    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... 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...

  13. Synthesis and characterization of novel aramid-zirconium oxide micro-composites

    Microsoft Academic Search

    H. U. Rehman; M. I. Sarwar; Z. Ahmad; H. Krug; H. Schmidt

    1997-01-01

    New micro-composites containing different proportions of zirconium oxide in aromatic polyamide have been prepared via a sol-gel process. Poly(phenyleneterephthalamide) chains with carbonyl chloride end groups were synthesized by reacting a mixture of p- and m-phenylene diamines with terephthaloyl chloride. The chain ends were endcapped with aminophenyltrimethoxysilane. Appropriate amount of zirconium propoxide solution (82.3 wt.%) in propanol was mixed in the

  14. Separation of Zirconium by Extraction Chromatography with Amberlite LA1 from Malonic Acid

    Microsoft Academic Search

    Prakash Narayanan; S. M. Khopkar

    1985-01-01

    Zirconium was separated by extraction chromatography with Amberlite LA-l as an extractant from 1 × 10 M to 2.5 to 10 M of malonic acid at pH 2.0 to 6.0. It was stripped with various mineral acids and determined spectro-photometrically with arsenazo-III at 665 nm. Zirconium was separated from alkali, alkaline earths, yttrium, lanthanum, chromium(III), manganese, cobalt, nickel, copper, zinc,

  15. Efficient UV-Emitting X-Ray Phosphors: Potassium Hafnium-Zirconium Phosphates

    E-print Network

    Li, Jing

    Efficient UV-Emitting X-Ray Phosphors: Potassium Hafnium-Zirconium Phosphates K2Hf1-xZrx(PO4 Abstract Potassium hafnium-zirconium phosphates, K2Hf1-xZrx(PO4)2 and KHf2(1-x)Zr2x(PO4)3 are broad-band UV.e., those with emission less than 400 nm). Attention was given to hafnium-oxide based phosphors because HfO2

  16. 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.

  17. Improved tribology of tool steel by zirconium ion implantation

    SciTech Connect

    Akbas, N.; Oztarhan, A.; Monteiro, O.R.; Brown, I.G.

    2001-02-01

    AISI D3 tool steel was ion implanted with zirconium and the improvement in surface tribological properties investigated. The Zr ion implantation was done using a metal vapor vacuum arc broad-beam ion source, with a mean ion energy of 130 keV and at doses of 3.6 x 10(sup 16), 5 x 10(sup 16) and 1 x 10(sup 17) ions/cm2. Wear, friction and hardness of the implanted samples were measured and compared to the performance of unimplanted steel. The wear resistance was increased by about a factor of two, the friction remained about the same or was possibly increased by a small amount, and the hardness was improved by a factor of five or more by the ion implantation. We also investigated the effect on the Zr implantation profile of the multi-component energy distribution of the ion beam used here.

  18. 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.

  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. Wear resistant zirconium base alloy article for water reactors

    SciTech Connect

    Gillett, J.E.; Shockling, L.A.; Sherwood, D.G.

    1988-03-01

    In a water reactor operating environment, the combination having improved fretting wear resistance is described comprising: an elongated tubular water displacer rod; having a low neutron absorption cross section guide support plates distributed along the length of the water displacer rod; the water displacer rod intersecting the guide support plates through apertures in the guide support plates; the water displacer rod having a plurality of spaced apart annular electrospark deposited coatings, each coating facing the wall of a respective aperture, the electrospark deposited coatings comprising Cr/sub 2/C/sub 3/; wherein the water displacer rod has a tube wall composed of a zirconium base alloy; and wherein the guide support plates are composed of a stainless steel alloy.

  1. Zirconium Copper - a New Material for Use at Low Temperatures?

    SciTech Connect

    Woodcraft, Adam L. [School of Physics and Astronomy, Cardiff University, Cardiff, 5 The Parade, Cardiff, CF24 3YB (United Kingdom)

    2006-09-07

    Cryogenic instruments usually require components with high thermal conductivity. Pure (non alloyed) copper offers very high conductivity, but is soft and not thus always suitable structurally. High conductivity beryllium copper (BeCu) alloys are a common choice when copper is unsuitable since they offer a good compromise between hardness and thermal conductivity. These alloys contain a small (<1%) amount of beryllium (along with a few percent of nickel or cobalt), with strength being obtained by precipitation hardening. An alternative precipitation hardened copper alloy is C15000 zirconium copper (ZrCu), which contains < 0.2% zirconium with the remainder being copper. This material does not seem to be generally used in cryogenic systems, though hardness and strength are comparable to BeCu. Moreover, the lower impurity content suggests that the thermal conductivity should be higher than for BeCu. I present residual resistivity measurements suggesting that ZrCu does indeed possess considerably higher conductivity than BeCu (19 Wm-1K-1 at 1 K compared to approximately 2 Wm-1K-1), and should therefore be a very useful material. A method is given for extrapolating the low temperature thermal conductivity values to temperatures up to 300 K; good agreement is seen with room temperature data-sheet values. This extrapolation method is shown to also be applicable to BeCu and thus presumably other dilute copper alloys, and is used to give recommended values for coin silver and various BeCu alloy types, including C17510 and C17200.

  2. Comparison of optical properties of nitrate and sulfate aerosol and the direct radiative forcing due to nitrate in China

    E-print Network

    Li, Zhanqing

    Comparison of optical properties of nitrate and sulfate aerosol and the direct radiative forcing due to nitrate in China H. Zhang a, , Z. Shen a,b , X. Wei a,c , M. Zhang d , Z. Li e,f a Laboratory the direct radiative forcing (DRF) due to nitrate aerosols. Ensuing errors have not been rigorously evaluated

  3. SOME ASPECTS OF THE ANION EXCHANGE BEHAVIOR OF URANYL NITRATE IN THE PRESENCE OF OTHER INORGANIC NITRATES

    Microsoft Academic Search

    J. K. Foreman; I. R. McGowan; T. D. Smith

    1959-01-01

    The addition of inorganic nitrates to aqueous solutions of uranyl ; nitrate enhances the uptake of uranium on the anion-exchange resin Deacidite FF ; in the onder anuninum> calcium> lithium> ammonium. The predominating cause is ; considered to be the facilitation of formation of nitrate complexes by the uranyl ; ion, and of the subsequent ion-exchange, due to the decrease

  4. Does the evidence about health risks associated with nitrate ingestion warrant an increase of the nitrate standard for drinking water?

    Microsoft Academic Search

    Hans JM van Grinsven; Mary H Ward; Nigel Benjamin; Theo M de Kok

    2006-01-01

    Several authors have suggested that it is safe to raise the health standard for nitrate in drinking water, and save money on measures associated with nitrate pollution of drinking water resources. The major argument has been that the epidemiologic evidence for acute and chronic health effects related to drinking water nitrate at concentrations near the health standard is inconclusive. With

  5. Genetic basis for nitrate resistance in Desulfovibrio strains.

    PubMed

    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

  6. Factors affecting the stress corrosion cracking susceptibility of zirconium in 90% nitric acid

    SciTech Connect

    Yau, T.L.

    1987-01-01

    U-bend, C-ring, and slow strain-rate tests have been performed to evaluate the effects of texture, stress, surface conditions, heat treatment, electrochemical potential, and strain rate on stress corrosion cracking (SCC) of zirconium in 90% nitric acid at room temperatures. It has been shown that careful control of texture, surface condition (scratching, cleaning and oxide coating), and/or applied stress can effectively lead to the prevention of SCC of zirconium in 90% HNO/sub 3/. Heat treating at 760/sup 0/C, 880/sup 0/C, or 1000/sup 0/C does not seem to improve the SCC resistance. However, if the potential of zirconium is maintained at 500 mV/sub SCE/ or lower, or 200 ppm of HF is added, zirconium's SCC susceptibility in 90% HNO/sub 3/ is eliminated. In the case of adding HF, zirconium sponge must also be added in order to avoid high corrosion rates. The mechanism for SCC of zirconium in 90% HNO/sub 3/ appears to be stress assisted local anodic dissolution, since the highest susceptibility is observed at strain rate = 7.5 x 10/sup -7//sec, and, at a higher or lower strain rate the susceptibility decreases. There is additional evidence to support this mechanism.

  7. Preparation of porous resin loaded with crystalline hydrous zirconium oxide and its application to the removal of arsenic

    Microsoft Academic Search

    Toshishige M. Suzuki; John O. Bomani; Hideyuki Matsunaga; Toshiro Yokoyama

    2000-01-01

    A porous resin loaded with monoclinic or cubic hydrous zirconium oxide was prepared by incorporation of ZrOCl2·8H2O into porous spherical polymer beads followed by hydrolysis and hydrothermal treatment of the zirconium salt. Hydrous zirconium oxide appeared to deposit inside the pores with relatively large diameter. The adsorption capacity and distribution coefficients for As(III) and As(V) were determined by batch procedures.

  8. Preparation of zirconium oxy ion-imprinted particle for the selective separation of trace zirconium ion from water.

    PubMed

    Ren, Yueming; Liu, Pingxin; Liu, Xiaoli; Feng, Jing; Fan, Zhuangjun; Luan, Tianzhu

    2014-10-01

    Zr(IV) oxy ion-imprinted particle (Zr-IIP) was prepared using the metal ion imprinting technique in a sol-gel process on the surface of amino-silica. The dosages of zirconium ions as imprinted target, (3-aminopropyl) triethoxysilane (APTES) as a functional monomer and teraethyl orthosilicate (TEOS) as a cross-linker were optimized. The prepared Zr-IIP and Zr(IV) oxy ion non-imprinted particle (Zr-NIP) were characterized. pH effect, binding ability and the selectivity were investigated in detail. The results showed that the Zr-IIP had an excellent binding capacity and selectivity in the water. The equilibrium data fitted well to the pseudo-second-order kinetic and the Langmuir model for Zr(IV) binding onto Zr-IIP, respectively. The saturate binding capacity of Zr-IIP was found to be 196.08 ?mol g(-1), which was 18 times higher than that of Zr-NIP. The sequence of binding efficiency of Zr-IIP for various ions was Zr(IV)>Cu(II)>Sb(III)>Eu(III). The coordination number has an important effect on the dimensional binding capacity. The equilibrium binding capacity of Zr-IIP for Zr(IV) decreased little under various concentrations of Pb(II) ions. The analysis of relative selectivity coefficient (Kr) indicated that the Zr-IIP had an appreciable binding specificity towards Zr(IV) although the competitive ions coexisted in the water. The Zr-IIP could serve as an efficient selective material for recovering or removing zirconium from the water environment. PMID:25004058

  9. Zirconium(IV) chloride catalyzed one-pot synthesis of 3,4-dihydropyrimidin-2(1 H)-ones

    Microsoft Academic Search

    Ch. Venkateshwar Reddy; M Mahesh; P. V. K Raju; T. Ramesh Babu; V. V. Narayana Reddy

    2002-01-01

    Zirconium tetrachloride catalyzes efficiently the three component condensation reaction of an aromatic aldehyde, a ?-ketoester and urea in refluxing ethanol to afford the corresponding dihydropyrimidinone in high yield.

  10. 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

  11. Electrophilic nitration of aromatics in ionic liquid solvents.

    PubMed

    Laali, K K; Gettwert, V J

    2001-01-12

    Potential utility of a series of 1-ethyl-3-methylimidazolium salts [emim][X] with X = OTf-, CF3COO-, and NO3- as well as [HNEtPri2][CF3COO] (protonated Hünig's base) ionic liquids were explored as solvent for electrophilic nitration of aromatics using a variety of nitrating systems, namely NH4NO3/TFAA, isoamyl nitrate/BF3.Et2O, isoamyl nitrate/TfOH, Cu(NO3)/TFAA, and AgNO3/Tf2O. Among these, NH4NO3/TFAA (with [emim][CF3COO], [emim][NO3]) and isoamyl nitrate/BF3.Et2O, isoamyl nitrate/TfOH (with [emim][OTf]) provided the best overall systems both in terms of nitration efficiency and recycling/reuse of the ionic liquids. For [NO2][BF4] nitration, the commonly used ionic liquids [emim][AlCl4] and [emim][Al2Cl7] are unsuitable, as counterion exchange and arene nitration compete. [Emim][BF4] is ring nitrated with [NO2][BF4] producing [NO2-emim][BF4] salt, which is of limited utility due to its increased viscosity. Nitration in ionic liquids is surveyed using a host of aromatic substrates with varied reactivities. The preparative scope of the ionic liquids was also extended. Counterion dependency of the NMR spectra of the [emim][X] liquids can be used to gauge counterion exchange (metathesis) during nitration. Ionic liquid nitration is a useful alternative to classical nitration routes due to easier product isolation and recovery of the ionic liquid solvent, and because it avoids problems associated with neutralization of large quantities of strong acid. PMID:11429927

  12. 4-Meth­oxy­benzamidinium nitrate

    PubMed Central

    Irrera, Simona; Portalone, Gustavo

    2012-01-01

    The title salt, C8H11N2O+·NO3 ?, was synthesized by a reaction between 4-meth­oxy­benzamidine (4-amidino­anisole) and nitric acid. The asymmetric unit comprises a non-planar 4-meth­oxy­benzamidinium cation and a nitrate anion. In the cation, the amidinium group has two similar C—N bond lengths [1.302?(3) and 1.313?(3)?Å] and its plane forms a dihedral angle of 32.66?(5)° with the mean plane of the benzene ring. The nitrate–amidinium ion pair is not planar, as the dihedral angle between the planes defined by the CN2 + and NO3 ? units is 19.28?(6)°. The ionic components are associated in the crystal via N—H?O hydrogen bonds, resulting in a three-dimensional network. PMID:23476172

  13. Detonation characteristics of prilled ammonium nitrate

    Microsoft Academic Search

    C. H. Winning

    1965-01-01

    Detonation characteristics of prilled ammonium nitrate vary greatly with physical factors. Minimum primer requirements and\\u000a minimum propagating diameters of industrial and fertilizer grade prills are compared as well as the detonation velocities\\u000a and blast effects of prill “shots” of various sizes and degrees of confinement. The sensitizing effect of elevated temperature\\u000a on AN detonations also is demonstrated.

  14. PhotoElastic Effect in Barium Nitrate

    Microsoft Academic Search

    S. Bhagavantam; D. Suryanarayana

    1948-01-01

    DURING the course of our investigations on photo-elasticity, we have found that single crystals of barium nitrate behave in many respects in an exceptional manner. Differences between the stress-optical constants as determined by a Babinet compensator are (q11 - q12) = - 23.81 × 10-13, (q11 - q13) = - 18.06 × 10-13 and q44 = - 1.62 × 10-13

  15. Ammonium nitrate: thermal stability and explosivity modifiers

    Microsoft Academic Search

    Jimmie C Oxley; James L Smith; Evan Rogers; Ming Yu

    2002-01-01

    Two basic approaches to diminish the explosivity of AN have been suggested: dilution of ammonium nitrate (AN) with a chemically inert material or incorporation of small amounts of material which increases the chemical reaction zone [Method of Desensitizing AN and the Product Obtained, United States Patent Office, No. 3,366,468 (1968); Fertilizer additives: can AN be defanged? C&E News (1995) 6].

  16. Peculiarities of the nitration of secondary polynitroalkanes

    SciTech Connect

    Eremenko, L.T.; Oreshko, G.V.; Fadeev, M.A.

    1986-12-20

    In the interaction of salts of 1,1,1,3,5,5,5-heptanitro- or 1,5-difluoro-1,1,3,5,5-pentanitropentanes with nitrating systems based no HNO/sub 3/, 1,1,1,3,3,5,5,5-octanitro- or 1,5-difluoro-1,1,3,3,5,5-hexanitropentanes, 1,1,1,5,5,5-hexanitro- or 1,5-difluoro-1,1,5,5-tetranitropentan-3-ones, the O-bis(2,2,2-trinitroethyl)nitromethyl ether of bis(2',2',2'-trinitroethyl)carboxime or the O-bis(2-fluoro-2,2-dinitroethyl)nitromethyl ether of bis(2'-fluoro-2',2'-dinitroethyl)carboxime are formed. The ratio of the reaction products depends on the composition of the nitrating system. The data obtained permit them to consider that the nitrating reagent is a nonionized form of HONO/sub 2/ or AcONO/sub 2/.

  17. Equation of State of Ammonium Nitrate

    NASA Astrophysics Data System (ADS)

    Robbins, David L.; Sheffield, Stephen A.; Dattelbaum, Dana M.; Velisavljevic, Nenad; Stahl, David B.

    2009-12-01

    Ammonium nitrate (AN) is a widely used fertilizer and mining explosive. AN is commonly used in ammonium nitrate-fuel oil (ANFO), which is a mixture of explosive-grade AN prills and fuel oil in a 94:6 ratio by weight. ANFO is a non-ideal explosive with measured detonation velocities around 4 km/s. The equation of state properties and known initiation behavior of neat AN are limited. We present the results of a series of gas gun-driven plate impact experiments on pressed neat ammonium nitrate at 1.72 g/cm3. No evidence of initiation was observed under shock loading to 22 GPa. High pressure x-ray diffraction experiments in diamond anvil cells provided insight into the high pressure phase behavior over the same pressure range (to 25 GPa), as well as a static isotherm at ambient temperature. From the isotherm and thermodynamic properties at ambient conditions, a preliminary unreacted equation of state (EOS) has been developed based on the Murnaghan isotherm and Helmholtz formalism [1], which compares favorably with the available experimental Hugoniot data on several densities of AN.

  18. Carbonyl Alkyl Nitrates as Trace Constituents in Urban Air

    NASA Astrophysics Data System (ADS)

    Woidich, S.; Gruenert, A.; Ballschmiter, K.

    2003-04-01

    Organic nitrates, esters of nitric acid, significantly contribute to the entire pool of odd nitrogen (NOY) in the atmosphere. Organic nitrates are formed in NO rich air by degradation of alkanes and alkenes initiated by OH and NO3 radicals during daytime and nighttime, respectively. Bifunctional organonitrates like the alkyl dinitrates and hydroxy alkyl nitrates are formed primarily from alkenes. The two main sources for Alkenes are traffic emissions and naturally occurring terpenes. So far a broad spectrum of alkyl dinitrates and hydroxy alkyl nitrates including six different isoprene nitrates has been identified in urban and marine air (1-3). We report here for the first time about the group of C4 C7 carbonyl alkyl nitrates as trace constituents in urban air collected on the campus of the University of Ulm Germany, and in the downtown area of Salt Lake City, Utah. Air sampling was done by high volume sampling (flow rate 25 m3/h) using a layer of 100 g silica gel (particle diameter 0.2 - 0.5 mm) as adsorbent. The organic nitrates were eluted from the silica gel by pentane/acetone (4:1, w/w) and the extract was concentrated to a volume of 500 µL for a group separation using normal phase HPLC. Final analysis was performed by high resolution capillary gas chromatography with electron capture detection as well as by mass selective detection in the (CH4)NCI mode using NO2- = m/e 46 as the indicator mass. The carbonyl alkyl nitrates were identified by self synthesized reference standards . So far we have identified eight non-branched a-carbonyl alkyl nitrates (vicinal carbonyl alkyl nitrates), two b-carbonyl alkyl nitrates and one g-carbonyl alkyl nitrate with carbon chains ranging from C4 to C7. The mixing ratios are between 0.05 and 0.30 ppt(v) for daytime samples and are two to three times higher for samples taken at night. (1) M. Schneider, O. Luxenhofer, Angela Deißler, K. Ballschmiter: 2C1-C15 Alkyl Nitrates, Benzyl Nitrate, and Bifunctional Nitrates: Measurements in Californian and South Atlantic Air and Global Comparison Using C2Cl4 and CHBr3 as Marker Molecules2 Environ. Sci. Technol. (1998) 32: 3055-3062. (2) G. Werner, J. Kastler, R. Looser, K. Ballschmiter: 2Organic nitrates of isoprene as atmospheric trace compounds2 Angewandte Chemie International Edition (1999) 38: 1634- 1637. (3) RG Fischer; J. Kastler, K. Ballschmiter, "Levels and pattern of alkyl nitrates, multifunctional alkyl nitrates, and halocarbons in the air over the Atlantic Ocean" J. Geophys. Res. - Atmosphere (2000) 105: 14 473-14 494.

  19. Induction of a high-capacity nitrate-uptake mechanism in barley roots prompted by nitrate uptake through a constitutive low-capacity mechanism

    Microsoft Academic Search

    Rudolf Behl; Rudolf Tischner; Klaus Raschke

    1988-01-01

    Roots of nitrate-starved and nitrate-pretreated seedlings of Hordeum vulgare were used to investigate the induction of a high-capacity uptake mechanism for nitrate. When exposed to 0.2 mmol·l-1KNO3, nitrate-starved roots took up nitrate at a rate of approx. 1 µmol·(g FW)-1·h-1; K+ was absorbed at a rate ten-times higher. Nitrate uptake accelerated after a lag of about 1 h, until it

  20. A Mechanism for the Aqueous Phase Production of Alkyl Nitrates

    NASA Astrophysics Data System (ADS)

    Dahl, E. E.; Saltzman, E. S.; DeBruyn, W. J.

    2002-05-01

    Measurements of alkyl nitrates in the surface ocean and marine boundary layer indicate that there is an oceanic source of alkyl nitrates to the marine troposphere. Alkyl nitrates make up a portion of the total reactive nitrogen in the troposphere. They can contribute significantly to the NOx budget in the remote marine atmosphere, affecting regional ozone formation. The origin of the alkyl nitrate in the surface ocean is unknown. One possible mechanism for aqueous alkyl nitrate formation is the reaction of alkyl peroxy radicals with NO (ROO + NO -> RONO2). Peroxy radicals and NO have been observed in seawater at levels that make this a viable reaction (Blough 1997) (Zafiriou and McFarland 1981). In this project, steady state irradiations of nitrite and alkane solutions were used to determine the yield of alkyl nitrates from this reaction. The yield for ethyl nitrate has been determined to be 101+/-12% and 102+/-8% total yield for propyl nitrates (n-propyl and iso-propyl) with no evident temperature dependence between 5 and 30° C. Alkyl nitrates were also generated by the irradiation of natural seawater and nitrite-spiked seawater. These results indicate that the proposed mechanism may be a viable source of alkyl nitrates in surface waters.

  1. 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

  2. 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.

  3. Cesium Adsorption on the ZIRCONIUM/OXYGEN/TUNGSTEN(100) Surface.

    NASA Astrophysics Data System (ADS)

    Chen, Hsiung-Ku.

    Interest in zirconium covered tungsten as an electrode material has been stimulated by recent work on the model surface Zr/O/W(100). This surface has been shown to have an effective thermionic work function of (TURN) 2.6 eV, when properly prepared, with very low volatility and excellent thermal stability. For advanced thermionic converter applications and for proposed future nuclear electric propulsion systems, the emitter requirement is (phi)(,eff) (LESSTHEQ) 2.4 eV at 1600 K. The corresponding collector must have a work function <(, )1.4 eV at (TURN) 600 K. For any electrode materials yet studied, these requirements dictate the presence of an equilibrium pressure of cesium vapor. The adsorption/desorption characteristics of cesium in the Zr/O/W(100) surface and the effect of cesium coverage on the surface work function have been studied, using Auger electron spectrometry (AES), field emission retarding potential work function measurements (FERP) and thermal desorption mass spectrometry (TDS). The minimum work function attained for cesium adsorption on the Zr/O/W(100) surface was 2.12 eV. The desorption spectrum of cesium from this surface shows major binding states at 1.1 and 1.3 eV, with desorption complete at T (LESSTHEQ) 900 K. Adsorption of excess oxygen on the low work function Zr/O/W(100) surface increases the affinity of the surface toward cesium and lowers the minimum work function. Cesium adsorbed on a saturated layer of excess oxygen shows a terminal desorption temperature of 1300 K and minimum work function of 1.37 eV. Thermal equilibrium of the excess oxygen removes some oxygen and zirconium from the surface, changing the cesium adsorption characteristics. Measurement of low energy electron reflection from the Zr/O/W(100) surface with and without adsorbed cesium indicates that the presence of cesium reduces the reflection coefficient of Zr/O/W(100) near the threshold beam potential for current collection. Two adsorption sites for Cs adsorption on clear W(100) were found in the thermal desorption spectra. The Cs/W(100) bonding is stronger than the bonding of Cs on Zr/O/W(100) surface.

  4. Inhibition of peroxynitrite dependent tyrosine nitration by hydroxycinnamates: nitration or electron donation?

    PubMed

    Pannala, A S; Razaq, R; Halliwell, B; Singh, S; Rice-Evans, C A

    1998-03-01

    Peroxynitrite is a cytotoxic species generated by the reaction between superoxide and nitric oxide. In this study the ability of hydroxycinnamate antioxidants to decrease peroxynitrite-mediated nitration of tyrosine was investigated. The results obtained show that all compounds were able to inhibit nitration of tyrosine. The potency of inhibitory activity was in the order; caffeic acid > or = chlorogenic acid > or = ferulic acid > p-coumaric acid > ocoumaric acid > m-coumaric acid. Trolox, which was included in the study for comparative purposes, had an activity between that of ferulic acid and p-coumaric acid. The data obtained suggest that hydroxycinnamates can act by one of two possible mechanisms: preferential nitration for monophenolates and electron donation by catecholates. PMID:9559872

  5. Bismuth nitrate-induced novel nitration of estradiol: an entry to new anticancer agents.

    PubMed

    Bandyopadhyay, Debasish; Rivera, Gildardo; Sanchez, Jorge L; Rivera, Jesse; Granados, Jose C; Guerrero, Adrian M; Chang, Fang-Mei; Dearth, Robert K; Short, John D; Banik, Bimal K

    2014-07-23

    Direct nitration of estradiol was carried out using metal nitrates on solid surfaces under mild condition, and a combination of bismuth nitrate pentahydrate impregnated KSF clay was found to be the best reagent to synthesize 2- and 4-nitroestradiol effectively. Furthermore, various basic side chains were introduced, through O-linker at C-3, to these nitroestradiols. The ability of these derivatives to cause cytotoxicity in Estrogen Receptor (ER)-positive and ER-negative breast cancer cell lines, as well as cancer cell lines of other origins, was examined. Qualitative structure activity relationship (SAR) has also been studied. We found that a basic side chain containing either a piperidine or morpholine ring, when conjugated to 2-nitroestradiol, was particularly effective at causing cytotoxicity in each of the cancer cell lines examined. Surprisingly, this effective cytotoxicity was even seen in ER-negative breast cancer cells. PMID:24946145

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

    PubMed

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

    2012-06-01

    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 2.3×10(6) 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

  7. A Lotus japonicus mutant defective in nitrate uptake is also affected in the nitrate response to nodulation.

    PubMed

    Pal'ove-Balang, P; García-Calderón, M; Pérez-Delgado, C M; Pavlovkin, J; Betti, M; Márquez, A J

    2015-01-01

    A chlorate-resistant mutant (Ljclo1) of the model legume Lotus japonicus was identified that showed normal levels of nitrate reductase enzyme activity but had decreased uptake of nitrate, as determined from nitrate depletion and electrophysiological measurements. The data suggest that the mutant could be affected specifically in the low-affinity but not in the high-affinity nitrate transport system, and also showed decreased uptake of chlorate. Back-crosses of the mutant plant to the wild type indicated that it is affected in a single Mendelian recessive trait. Thus, the mutation produced in Ljclo1 may be related to some of the low-affinity nitrate transporters or to a regulatory mechanism associated with nitrate/chlorate uptake. Both size and chlorophyll content in young leaves of the mutant plants were significantly reduced compared to the wild type. In addition, nodulation performance of the mutant plants was similar to the wild type in the absence of any exogenous nitrate. However, the nodule:root biomass ratio in mutant plants was considerably reduced in the presence of 1-2 mm nitrate. The levels of several transcripts for nitrate transport and assimilation genes were determined for the wild type and mutant plants and were slightly different. The results suggest interdependence between nitrate uptake, plant growth and nodulation in Ljclo1 mutant plants. PMID:24673996

  8. MOSSBAUER STUDIES OF DILUTE ERBIUM IMPURITIES IN ZIRCONIUM HYDRIDES* G.K. Shenoy, B.D. Dunlap, D.G. Westlake and A.E. Dwight*

    E-print Network

    Boyer, Edmond

    MOSSBAUER STUDIES OF DILUTE ERBIUM IMPURITIES IN ZIRCONIUM HYDRIDES* G.K. Shenoy, B.D. Dunlap, D. Introduction.- Zirconium metal forms two stable hydrides, 6 and e (Fig. 1), which have vastly diffe- rent such a study of Er3+ impurities in &- and e- phase zirconium hydrides. 2. Experimental methods and results

  9. DIFFUSION ELASTIQUE D'ELECTRONS SUR LE ZIRCONIUM-90 ET LE MOLYBDENE-92 Phan Xuan Ho, J.B. Bellicard, A. Bussire, Ph. Leconte et M. Priou

    E-print Network

    Paris-Sud XI, Université de

    DIFFUSION ELASTIQUE D'ELECTRONS SUR LE ZIRCONIUM-90 ET LE MOLYBDENE-92 Phan Xuan Ho, J.B. Bellicard-sur-Yvette, France. Rés&.- La diffusion élastique d'électrons sur le zirconium-90 et le molybdène-92 a été mesurée gaussien parabolique comme distribution de charge. Pour le zirconium- 90, nous comparons ce modèle aux

  10. Emulsions stabilized by precipitates of zirconium and tributyl phosphate degradation products

    SciTech Connect

    Sugai, H.; Munakata, K. (Sumitomo Metal Mining Co., Ltd., Tokai Research Center 2600, Ishigamitojuku, Tokai-mura, Ibaraki-ken 319-11 (JP)); Miyachi, S.; Yasu, S. (Power Reactor and Nuclear Fuel Development Corp., Tokai Works Reprocessing Plant, Analysis Section, Tokai-mura, Ibaraki-ken 319-11 (JP))

    1992-05-01

    In the Purex process, a solvent extraction method of nuclear fuel reprocessing, a stable emulsion called crud forms at the interface between the oil and water phases. This paper reports that crud is an emulsion stabilized by finely dispersed solids. Insoluble residues and precipitates of zirconium and radiation-degraded products of tributyl phosphate (TBP) are key materials in crud formation. Cruds formed by precipitates of zirconium and TBP degradation products, such as di-n-butyl phosphate (HDBP), mono-n-butyl phosphate (H{sub 2}MBP), and phosphoric acid (H{sub 3}PO{sub 4}) are studied. Experimental results show that the precipitate of zirconium and HDBP is not effective in stabilizing emulsions. However, the refractory complex of zirconium and H{sub 3}PO{sub 4} is an important material for stabilizing an oil-in-water emulsion in a solution with or without uranium. Moreover, it is shown that the complex of zirconium and H{sub 2}MBP has a significant role in stabilizing a water-in-oil emulsion, especially when uranium is also present.

  11. Investigation of zirconium oxynitride thin films deposited by reactive pulsed magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Mohamed, S. H.; Abd El-Rahman, A. M.; Ahmed, Mahrous R.

    2007-11-01

    Zirconium oxynitride films were deposited onto glass and Si (1 0 0) substrates at room temperature by pulsed reactive dc magnetron sputtering of a metallic Zr target in an Ar/O2/N2 atmosphere. The structural, compositional and optical properties of the deposited films were found to depend on the ratio of nitrogen partial pressure to the total reactive gas partial pressure. Morphology investigation by atomic force microscopy showed that most of the zirconium oxynitride coatings have smooth surfaces (average roughness 2.5 nm). X-ray diffraction measurements revealed a change from the monoclinic zirconium oxide phase to the orthorhombic, and then a change to the cubic zirconium nitride phase upon changing the nitrogen content in the films. Optical properties of zirconium oxynitride films were analysed by a spectrophotometer and computer simulations. The calculated refractive index of transparent and semi-transparent films was found to be in the range 2.05-4.73 (at 650 nm). The optical band gap changed from 3.67 to 1.59 eV with changing nitrogen content. This study allows the elaboration process optimization and then the control of the film composition and properties, which is very interesting for a technological transfer.

  12. Surface modification of biomedical AISI 316L stainless steel with zirconium carbonitride coatings

    NASA Astrophysics Data System (ADS)

    Wang, L.; Zhao, X.; Ding, M. H.; Zheng, H.; Zhang, H. S.; Zhang, B.; Li, X. Q.; Wu, G. Y.

    2015-06-01

    In the paper, by using radio frequency (rf) magnetron sputtering method, a zirconium carbonitride coating was produced on AISI 316L austenitic stainless steel. The influence of substrate temperature (Ts) on microstructure, mechanical properties, corrosion resistance and hemocompatibility were then investigated. XRD and TEM results revealed that the zirconium carbonitride coatings were almost amorphous when Ts was below 400°C, while nanostructured Zr2CN was formed at Ts of 400 °C. The nanocrystalline formation resulted in a significant increase in the nanohardness of zirconium carbonitride coatings from 17 GPa to over 32 GPa. Electrochemical testing showed that the stable zirconium carbonitride coating had improved the corrosion resistance of AISI 316L stainless steel substrate material. The characterization of platelet adhesion indicated that the zirconium carbonitride coatings presented better hemocompatibility when Ts varied from 25 °C to more than 200 °C, which may be due to the lower surface roughness, interfacial tension and the rate ?sd /?sp , where ?sd and ?sp are the disperse component and polar component of the surface, respectively.

  13. Pulsed single-mode laser ionization of hyperfine levels of zirconium-91

    SciTech Connect

    Hackett, P.A.; Morrison, H.D.; Bourne, O.L.; Simard, B.; Rayner, D.M.

    1988-12-01

    We identify a considerable improvement in proposed schemes for isotopic depletion of zirconium-91 on the basis of the atomic vapor laser isotope separation (AVLIS) method. The improvement lies in applying a single-longitudinal-mode dye laser for selective excitation of all hyperfine split levels of the ground state of zirconium-91. High-resolution laser-induced fluorescence spectroscopy of atomic beams of zirconium produced through laser vaporization--supersonic expansion has been used to identify transitions of zirconium with suitable hyperfine structure. Casimir magnetic-dipole and electric-quadrupole coupling constants and isotope shifts have been derived and are reported for five excited configurations. Suitable intermediate levels in a multistep resonance ionization pathway have been identified by two-color resonance ionization spectroscopy. Isotope depletion has been demonstrated on one ground state transition (z /sup 3/F/sup circle-open//sub 3/ left-arrowa /sup 3/F/sub 2/ at 593.7 nm) by using a specially constructed pulsed, single-longitudinal-mode dye-laser oscillator. Prospects and future directions in zirconium AVLIS are discussed.

  14. 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.

  15. A comparative study of zirconium and titanium implants in rat: osseointegration and bone material quality.

    PubMed

    Hoerth, Rebecca M; Katunar, María R; Gomez Sanchez, Andrea; Orellano, Juan C; Ceré, Silvia M; Wagermaier, Wolfgang; Ballarre, Josefina

    2014-02-01

    Permanent metal implants are widely used in human medical treatments and orthopedics, for example as hip joint replacements. They are commonly made of titanium alloys and beyond the optimization of this established material, it is also essential to explore alternative implant materials in view of improved osseointegration. The aim of our study was to characterize the implant performance of zirconium in comparison to titanium implants. Zirconium implants have been characterized in a previous study concerning material properties and surface characteristics in vitro, such as oxide layer thickness and surface roughness. In the present study, we compare bone material quality around zirconium and titanium implants in terms of osseointegration and therefore characterized bone material properties in a rat model using a multi-method approach. We used light and electron microscopy, micro Raman spectroscopy, micro X-ray fluorescence and X-ray scattering techniques to investigate the osseointegration in terms of compositional and structural properties of the newly formed bone. Regarding the mineralization level, the mineral composition, and the alignment and order of the mineral particles, our results show that the maturity of the newly formed bone after 8 weeks of implantation is already very high. In conclusion, the bone material quality obtained for zirconium implants is at least as good as for titanium. It seems that the zirconium implants can be a good candidate for using as permanent metal prosthesis for orthopedic treatments. PMID:24170339

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

    SciTech Connect

    Khazeni, Nasser, E-mail: khazeni.n@gmail.com [Chemical Engineering Department, Middle East Technical University, Ankara 06531 (Turkey)] [Chemical Engineering Department, Middle East Technical University, Ankara 06531 (Turkey); Mavis, Bora, E-mail: bmavis@hacettepe.edu.tr [Mechanical Engineering Department, Hacettepe University, Beytepe Ankara 06800 (Turkey)] [Mechanical Engineering Department, Hacettepe University, Beytepe Ankara 06800 (Turkey); Guenduez, Guengoer, E-mail: ggunduz@metu.edu.tr [Chemical Engineering Department, Middle East Technical University, Ankara 06531 (Turkey)] [Chemical Engineering Department, Middle East Technical University, Ankara 06531 (Turkey); Colak, Uner, E-mail: ucolak@hacettepe.edu.tr [Nuclear Engineering Department, Hacettepe University, Beytepe Ankara 06800 (Turkey)] [Nuclear Engineering Department, Hacettepe University, Beytepe Ankara 06800 (Turkey)

    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.

  17. Simulated knee wear with cobalt chromium and oxidized zirconium knee femoral components.

    PubMed

    White, S E; Whiteside, L A; McCarthy, D S; Anthony, M; Poggie, R A

    1994-12-01

    A knee simulator that mimics the plowing/rolling wear mechanisms of the knee was used to compare wear properties of cobalt chromium and oxidized zirconium femoral components. The simulator flexes and extends the knee so that the femoral components travels from 0 degrees to 30 degrees while applying axial loads from 130 to 1300 lb. Three oxidized zirconium and 3 cobalt chromium femoral components were tested with 10-mm tibial polyethylene components. The oxidized zirconium femoral components caused significantly less ultra high molecular weight polyethylene wear than cobalt chromium femoral components. Tibial inserts that were articulated against the cobalt chromium components had evidence of scratching, burnishing, and delamination, but none of the surfaces that were articulated against oxidized zirconium components had evidence of delamination. Cobalt chromium surface roughness significantly increased during the 2,000,000 cycle test, but oxidized zirconium surface roughness was not affected. Polyethylene wear was correlated to a significant degree with the surface roughness of the femoral components. The improved wear characteristics of the ceramic articular surfaces can be explained by the wettability of the ceramic surface, which minimized adhesive wear, and the resistance of the hard, ceramic surface to roughening. PMID:7994957

  18. Zirconium phosphate waste forms for low-temperature stabilization of cesium-137-containing waste streams

    SciTech Connect

    Singh, D.; Wagh, A.S.; Tlustochowicz

    1996-04-01

    Novel chemically bonded phosphate ceramics are being developed and fabricated for low-temperature stabilization and solidification of waste streams that are not amenable to conventional high-temperature stabilization processes because volatiles are present in the wastes. A composite of zirconium-magnesium phosphate has been developed and shown to stabilize ash waste contaminated with a radioactive surrogate of {sup 137}Cs. Excellent retainment of cesium in the phosphate matrix system was observed in Toxicity Characteristic Leaching Procedure tests. This was attributed to the capture of cesium in the layered zirconium phosphate structure by intercalation ion-exchange reaction. But because zirconium phosphate has low strength, a novel zirconium/magnesium phosphate composite waste form system was developed. The performance of these final waste forms, as indicated by compression strength and durability in aqueous environments, satisfy the regulatory criteria. Test results indicate that zirconium-magnesium-phosphate-based final waste forms present a viable technology for treatment and solidification of cesium-contaminated wastes.

  19. Distribution of nitrate in ground water, Redlands, California

    USGS Publications Warehouse

    Eccles, Lawrence A.; Bradford, Wesley L.

    1977-01-01

    Wells producing water with nitrate as nitrogen concentrations in excess of 10 milligrams per liter are common throughout the Redlands, Calif., area. Nitrite as nitrogen concentrations in water from the saturated part of the aquifer ranged from much greater than 20 milligrams per liter at the water table to less than 5 milligrams per liter at depths of 300 feet below the water table. This depth dependence suggests that the major source of nitrate is a generalized area-wide infiltration of high-nitrate water downward from the surface through the unsaturated zone. The nitrate concentration in water from individual wells is dependent primarily upon depth and well construction--particularly aquifer seal and aquifer penetration--and secondarily upon well location. Nitrate concentrations of water in wells are increased by heavy pumping which causes high-nitrate water near the water table to be pulled deeper. (Woodard-USGS)

  20. 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.

  1. Study of a zirconium getter for purification of xenon gas

    E-print Network

    Dobi, A; Hall, C; Kaufman, L; Langford, T; Slutsky, S; Yen, Y R

    2010-01-01

    Oxygen, nitrogen and methane purification efficiencies for a common zirconium getter are measured in 1050 Torr of xenon gas. Starting with impurity concentrations near 10^{-6} g/g, the outlet impurity level is found to be less than 120*10^{-12} g/g for O2 and less than 950*10^{-12} g/g for N2. For methane we find residual contamination of the purified gas at concentrations varying over three orders of magnitude, depending on the purifier temperature and the gas flow rate. A slight reduction in the purifier's methane efficiency is observed after 13 mg of this impurity has been absorbed, which we attribute to partial exhaustion of the purifier's capacity for this species. We also find that the purifier's ability to absorb N2 and methane can be extinguished long before any decrease in O2 performance is observed, and slower flow rates should be employed for xenon purification due to the cooling effect that the heavy gas has on the getter.

  2. Effects of fast neutron irradiation on zirconium carbide

    NASA Astrophysics Data System (ADS)

    Snead, Lance L.; Katoh, Yutai; Kondo, Sosuke

    2010-04-01

    High-purity zone refined zirconium carbide has been fast neutron irradiated in the dose and temperature range of 1-10 × 10 25 N/m 2 ( E > 0.1 MeV) and 635-1480 °C, respectively. Non-irradiated and as-irradiated properties were measured including the lattice parameter, hardness and elastic modulus as determined through nano-indentation, thermal conductivity, and indentation fracture toughness. The effects of neutron irradiation on the microstructure were also determined though using transmission electron microscopy. The general finding of this paper, limited to this particular zone refined ZrC of nominal C/Zr ratio of 0.93, is that this ceramic is quite stable under neutron irradiation in the temperature and dose range studied. Measurement of lattice parameter before and after irradiation indicated a lack of significant crystalline strain due to irradiation. Only modest changes were observed in the mechanical properties of hardness, elastic modulus, and indentation fracture toughness. The thermal conductivity underwent a slight reduction near 1000 °C irradiation, though was essentially unchanged for 1300-1480 °C irradiation. Transmission electron microscopy revealed black-spot-type defects (likely Frank or other small loops) for irradiation at 670 °C, maturing to faulted Frank loops at 1280 °C. As the irradiation temperature increased from 1280 °C to the highest irradiation temperature, of 1496 °C, a transition to prismatic loops occurs.

  3. 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.

  4. Zirconium and hafnium Salalen complexes in isospecific polymerisation of propylene.

    PubMed

    Press, Konstantin; Venditto, Vincenzo; Goldberg, Israel; Kol, Moshe

    2013-07-01

    The activity of dibenzylzirconium and dibenzylhafnium Salalen complexes in polymerisation of propylene with MAO as a cocatalyst is described. Three Salalen ligand precursors combining a bulky alkyl group (1-adamantyl) on the imine-side phenol and electron withdrawing halo groups of different sizes on the amine-side phenol were explored. All metal complexes were obtained as single diastereomers. An X-ray crystallographic structure of a hafnium complex of an additional ligand carrying the combination of tert-butyl and chloro substituted phenolates, 4-Hf, revealed a fac-mer wrapping of the Salalen ligand around the metal centre. All complexes led to active catalysts in propylene polymerisation and to isotactic polypropylene of high regioregularity. The zirconium complexes led to polypropylene having molecular weights of Mw = 132,000-200,000 and isotacticities of [mmmm] = 65.7-75.0%. The hafnium complexes led to polypropylene of higher molecular weights of Mw = 375,000-520,000 and higher stereoregularities of [mmmm] = 80.6-89.3%, the highest isotacticity obtained with 3-Hf. PMID:23471354

  5. 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.

  6. 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.

  7. 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

  8. Nanocrystallization of zirconium subjected to surface mechanical attrition treatment

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Han, Y.; Lu, J.

    2008-04-01

    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.

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

    SciTech Connect

    Sina, Younes [University of Tennessee, Knoxville (UTK); McHargue, Carl J [University of Tennessee, Knoxville (UTK); Duscher, Gerd [University of Tennessee, Knoxville (UTK); Zhang, Yanwen [ORNL

    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.

  10. 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.

  11. Corrosion Cracking of Zirconium Cladding Tubes. A Review. 2. Effect of External Factors, Structure, and Properties of the Alloys

    Microsoft Academic Search

    S. A. Nikulin; A. B. Rozhnov

    2005-01-01

    Data on the effect of various external factors (applied loads, iodine concentration, temperature, irradiation), structure,\\u000a and properties (strength, state of the surface, residual stresses, and hydrogen charging) of zirconium alloys on the mechanisms\\u000a of and resistance to stress corrosion cracking (SCC) of zirconium cladding tubes primarily in iodine-bearing media are presented.

  12. The effect of zirconium oxide and quartz pigments on the heat and corrosion resistance properties of the silicone based coatings

    Microsoft Academic Search

    L. Mathivanan; A. K. Arof

    2000-01-01

    Silicone resin based protective coatings are generally used for high temperature applications. In this work, anti-corrosive and heat resistant properties of titanium dioxide, mica, zirconium oxide and quartz combination pigments with silicone resin as carrier vehicle in primer and top coat for mild steel surface have been evaluated. Promising results were obtained, showing that the ceramic pigments (zirconium oxide and

  13. Phase equilibria in uranium-rich binary alloys containing molybdenum and zirconium and the effect of ternary additions of carbon

    Microsoft Academic Search

    R. L. Craik; D. Birch; C. Fizzotti; F. Saraceno

    1962-01-01

    The metallographic characteristics of the microstructures obtained when ; uranium rich alloys are slowly cooled to room temperature, with intervening step-; annealing treatments at and below 950 deg C, are described. These alloys contain ; binary additions of molybdenum and zirconium and ternary additions of carbon with ; molybdenum or zirconium. The optical and particularly the replica electron ; microscope

  14. The nitrate-selective sensor with crystalline membrane

    Microsoft Academic Search

    Yu. E. Ermolenko; V. V. Kolodnikov; S. Al-Marok; Yu. G. Vlasov

    1995-01-01

    The nitrate-selective sensor developed in the Laboratory of Chemical Sensors of St. Petersburg University has been applied for the potentiometric determination of the nitrate ion in solution. It was found that the linear Nernstian response is from 1 to 6 pNO3 for these sensors. A simple analytical procedure for the nitrate-ion determination with crystalline membrane sensors can be used for

  15. MICROMACHINED AMPEROMETRIC NITRATE SENSOR WITH AN ANION PERMEABLE MEMBRANE

    Microsoft Academic Search

    Dohyun Kim; Ira B. Goldberg; Jack W. Judy

    A nitrate-sensing system that consists of a micromachined sensor substrate, anion-permeable membrane, integrated microfluidic channels, and standard fluidic connectors has been designed, fabricated, assembled, and tested. Our microsensor was designed for in-situ monitoring of nitrate concentrations in ground water. A silver electrode was patterned for amperometric nitrate detection. An electrochemically oxidized silver electrode was used as a reference electrode. Microfluidic

  16. Cryo-vacuum BRDF measurements of MMH-nitrate

    NASA Astrophysics Data System (ADS)

    Krone-Schmidt, Wilfried; Loveridge, Ronald C.

    1992-12-01

    Exhaust from bipropellant rocket boosters is a potential source of contamination for cooled sensor optics. The effect of monomethyl hydrazine nitrate (MMH-nitrate) on scatter at 3.39 microns is investigated as a function of temperature in the range of 200-350 Kelvin and as a function of thickness. The space-simulated deposition of MMH-nitrate took place under high vacuum onto a bare beryllium mirror.

  17. Quantitative Collection Of Total Inorganic Atmospheric Nitrate On Nylon Filters

    Microsoft Academic Search

    Daniel Grosjean

    1982-01-01

    Quantitative collection of total inorganic atmospheric nitrate, i.e., gaseous nitric acid (HONO2) and particulate nitrate (NO 3) on nylon filters is demonstrated on the basis of field studies conducted during Los Angeles smog episodes (NO3 = 1–44 pg m, HONO2=1–36 ?g m, total nitrate = 5–47 ?g m, T = 10–33°C, RH = 16–99%, ozone up to 460 ppb) and

  18. Dynamic microbial response of sulfidogenic wastewater biofilm to nitrate

    Microsoft Academic Search

    Janani Mohanakrishnan; Michael Vedel Wegener Kofoed; Jeremy Barr; Zhiguo Yuan; Andreas Schramm; Rikke Louise Meyer

    Nitrate is one of the chemicals often added to wastewater to control hydrogen sulfide production by sulfate-reducing bacteria\\u000a (SRB). While the effect of nitrate in various SRB pure cultures is well documented, the effect observed in mixed microbial\\u000a communities is not consistent. This study investigates the response of mixed SRB communities to nitrate, by examining the\\u000a changes in activity and

  19. Photochemical Production of Alkyl Nitrates in the Tropical Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Dahl, E. E.; Yvon-Lewis, S. A.; Saltzman, E. S.

    2005-12-01

    Alkyl nitrates are important to the tropospheric NOx/ozone cycle because they represent a significant fraction of the reactive nitrogen (NOy). Previous work has shown that there is an oceanic source of alkyl nitrates. A photochemical mechanism for the formation of alkyl nitrates in seawater has been proposed. This mechanism involves the reaction of ROO and NO, where ROO is an alkyl peroxy radical. ROO and NO radicals in seawater are derived from the photolysis of DOM and nitrite, respectively. In this study, the photochemical production of low molecular weight alkyl nitrates (C1-C3) was observed in shipboard incubation experiments in the tropical Pacific during the PHASE 1 cruise. Seawater samples from several regions, including high and low-chlorophyll areas, were collected and incubated. Alkyl nitrate production rates as high as 2 nM/hour were observed. The production rate of alkyl nitrates was clearly dependent upon the initial concentration of nitrite, most likely as the source for NO radicals. While the magnitude of production varied between sample locations, the ratios of the production rates of the various alkyl nitrates remained relatively constant. The observed production ratios of methyl, ethyl, isopropyl, and n-propyl nitrate were 5.9:1.0:0.1:0.2. These ratios presumably reflect the speciation of peroxy radicals formed in seawater, and the yield of alkyl nitrates from the ROO+NO reaction. The observed production rate ratios are similar to the concentration ratios of alkyl nitrates observed in ambient seawater and the overlying atmosphere during the study. A comparison of the measured production rates and the observed concentrations, suggests that photochemically produced alkyl nitrates are a major source of atmospheric alkyl nitrates in the surface ocean and marine atmosphere.

  20. Electrochemical cell having an alkali-metal-nitrate electrode

    DOEpatents

    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.

  1. ENGINEERED BIORETENTION FOR REMOVAL OF NITRATE FROM STORMWATER RUNOFF

    Microsoft Academic Search

    Hunho Kim; Eric A. Seagren; Allen P. Davis

    ABSTRACT Control of nitrate from urban stormwater runoff can have a significant impact on nitrate levels in local waters. One option for providing treatment to urban stormwater runoff is bioretention,a simple plant- and soil-based low impact treatment\\/infiltration facility. The goal of this study is to re-engineer the concept of bioretention to remove nitrate from urban runoff. Specifically, a modification to

  2. 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

  3. 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

  4. Nitrate impacts on the Florida apple snail, Pomacea paludosa

    Microsoft Academic Search

    Norah Myers Corrao; Philip C. Darby; Christopher M. Pomory

    2006-01-01

    Nitrate pollution in springs in Florida has been suggested as a possible reason for declining populations of the Florida apple\\u000a snail, Pomacea paludosa (Say). No correlation was found between snail density and nitrate concentration measured in six Florida springs. In laboratory\\u000a studies examining short-term acute impacts of nitrate, adult and juvenile snail 96 h LC50 values could not be determined due

  5. Removal of nitrate from water by electroreduction and electrocoagulation

    Microsoft Academic Search

    A. Sava Koparal; Ülker Bakir Ö?ütveren

    2002-01-01

    The aim of this work was to investigate the feasibility of the removal of nitrate from water by applying electrochemical methods such as electroreduction and electrocoagulation. In electroreduction, removal of nitrate to an allowable concentration has been accomplished at the pH range of 5–7 with energy consumption value of 1×10?3kWhg?1. In electrocoagulation, an allowable concentration of nitrate has been achieved

  6. Nitration of N-substituted N?-trimethylsilylcarbodiimides

    Microsoft Academic Search

    A. M. Churakov; B. N. Khasapov; S. L. Ioffe; V. A. Tartakovskii

    1982-01-01

    1.Two new N-trimethylsilylated carbodiimides with functional substitution, N-carbomethoxy-N'-trimethylsilylcarbodiimide and N-methanesulfonyl-N'-trimethylsilylcarbodiimide were synthesized.2.The nitration of these carbodiimides using nonacidic nitrating agents proceeds with transfer of the reaction site and leads to N-nitro-N-carbomethoxycyanamide and N-nitro-N-methanesulfonylcyanamide, respectively.3.The nitration of N-methanesulfonyl-N'-trimethylsilylcarbodiimide using nitrogen pentoxide, similar to the reaction of N-nitro-N-methanesulfonylcyanamide with trimethylsilyl nitrate, leads to the trimethylsilyl ester of methanesulfonic acid.4.N-Nitro-N-methanesulfonyl cyanamide and N-nitro-N-carbomethoxycyanamide

  7. 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.

  8. Who is drinking nitrate in their well water?

    SciTech Connect

    Mitchell, T.J.; Harding, A.K. [Oregon State Univ., Corvallis, OR (United States). Dept. of Public Health

    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.

  9. Accumulation of Nitrate in Vegetables and Its Possible Implications to Human Health

    Microsoft Academic Search

    Shao-ting DU; Yong-song ZHANG; Xian-yong LIN

    2007-01-01

    In recent times, there are two kinds of completely opposite viewpoints about the impacts of nitrate on human health. To further objectively understand the effects of nitrate on human health, both of harmfulness and possible benefits of nitrate to human body, it is discussed in this review from the aspects of nitrate accumulation in vegetables, the source of nitrate ingested

  10. Evaluating factors influencing groundwater vulnerability to nitrate pollution: developing the potential of GIS

    Microsoft Academic Search

    Iain R Lake; Andrew A Lovett; Kevin M Hiscock; Mark Betson; Aidan Foley; Gisela Sünnenberg; Sarah Evers; Steve Fletcher

    2003-01-01

    The 1991 EU Nitrate Directive was designed to reduce water pollution from agriculturally derived nitrates. England and Wales implemented this Directive by controlling agricultural activities within their most vulnerable areas termed Nitrate Vulnerable Zones. These were designated by identifying drinking water catchments (surface and groundwater), at risk from nitrate pollution. However, this method contravened the Nitrate Directive because it only

  11. Simple approximation of nitrate diffusion from saltstone

    SciTech Connect

    Wallace, R.M.; Yau, W.W.F.; Grant, M.W.

    1985-12-04

    This report describes: (1) The justification for using one dimensional semi-infinite solid, with zero surface concentration, as an adequate model for saltstone leaching. (2) A simplified model involving leaching from a monolith into a well stirred tank to describe the transient salt concentration in the soil as the water in it migrates toward the saturated zone. (3) The effect, on the flux of sodium nitrate into the soil, of a slab of material such as clay or cement, placed between the saltstone and soil. It is assumed that the material in intermediate between that of the saltstone and soil.

  12. Nitration of ?-tocopherol in plant tissues

    Microsoft Academic Search

    Christine Desel; Eva Maria Hubbermann; Karin Schwarz; Karin Krupinska

    2007-01-01

    Nitration of ?-tocopherol has been suggested to be an important mechanism for the regulation and detoxification of reactive\\u000a nitrogen oxide species in animal tissues. To investigate whether this reaction does also occur in plants, reversed phase high-performance\\u000a liquid chromatography (HPLC) and mass spectrometry (LC-MS) were used for analysis of 5-nitro-?-tocopherol (5-N?T) in leaves\\u000a and seeds. 5-nitro-?-tocopherol (5-N?T) could be detected

  13. Evaluation of ferrocyanide/nitrate explosive hazard

    SciTech Connect

    Cady, H.H.

    1992-06-01

    Los Alamos National Laboratory agreed to assist Pacific Northwest Laboratory in the Ferrocyanide Safety Evaluation Program by helping to evaluate the explosive hazard of several mixtures of simulated ferrocyanide waste-tank sludge containing sodium nitrite and sodium nitrate. This report is an evaluation of the small-scale safety tests used to assess the safety of these materials from an explosive point of view. These tests show that these materials are not initiated by mechanical insult, and they require an external heat source before any exothermic chemical reaction can be observed.

  14. 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.

  15. o-Phenyl­enediaminium chloride nitrate

    PubMed Central

    Soudani, Sarra; Kefi, Riadh; Jelsch, Christian; Wenger, Emmanuel; Ben Nasr, Cherif

    2013-01-01

    In the title mol­ecular salt, C6H10N2 2+·NO3 ?·Cl?, the complete cation is generated by a crystallographic mirror plane. The complete nitrate ion is also generated by reflection, with the N atom and one O atom lying on the mirror plane; the chloride ion also lies on the reflection plane. In the crystal, the components are linked by N—H?Cl and N—H?(N,O) hydrogen bonds, forming (001) layers with the benzene rings projecting into the inter­layer regions. The layers are linked by weak C—H?O hydrogen bonds, generating a three-dimensional network. PMID:23634127

  16. Eutectic composite explosives containing ammonium nitrate

    SciTech Connect

    Stinecipher, M.M.

    1981-01-01

    The eutectic of ammonium nitrate (AN), the ammonium salt of 3,5-dinitro-1,2,4-triazole was prepared and its sensitivity and performance were studied. It was found that this AN formulation was unusual in that it performed ideally at small diameter, which indicated that it was a monomolecular explosive. Sensitivity tests included type 12 impact, Henkin thermal and wedge tests, and performance tests included rate stick/plate dent, cylinder, and aquarium tests. Results were compared with calculations, standard explosives, and another eutectic, ethylendiamine dinitrate (EDD)/AN.

  17. Nitrates and detinning in canned carrots

    E-print Network

    Florine, Thomas Edward

    1968-01-01

    . Information is needed regarding variables related to nitrates such as variety, maturity, storage and handling procedures, and the possible use of chelating agents in the canned product. CHAPTER II REVIEW OF LITERATURE Carrots have held a prominent... or depolarizers, and when present in suf- ficient quantities can remove nearly all of the tin from the internal surface of the can in a very short time. No gas is produced in this type of corrosion until most of the iron of the container is exposed...

  18. 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...

  19. Molecular basis of nitrate uptake by the plant nitrate transporter NRT1.1

    PubMed Central

    Parker, Joanne L.; Newstead, Simon

    2014-01-01

    Summary The NRT1/PTR family of proton-coupled transporters are responsible for nitrogen assimilation in eukaryotes and bacteria through the uptake of peptides. However, in the majority of plant species members of this family have evolved to transport nitrate as well as additional secondary metabolites and hormones. In response to falling nitrate levels, NRT1.1 is phosphorylated on an intracellular threonine that switches the transporter from a low to high affinity state. Here we present both the apo and nitrate bound crystal structures of Arabidopsis thaliana NRT1.1, which together with in vitro binding and transport data identify a key role for His356 in nitrate binding. Our data support a model whereby phosphorylation increases structural flexibility and in turn the rate of transport. Comparison with peptide transporters further reveals how the NRT1/PTR family has evolved to recognize diverse nitrogenous ligands, whilst maintaining elements of a conserved coupling mechanism within this superfamily of nutrient transporters. PMID:24572366

  20. Sources of aerosol nitrate to the Gulf of Aqaba: Evidence from 15 O of nitrate

    E-print Network

    Paytan, Adina

    a Department of Organismic and Evolutionary Biology, 16 Divinity Avenue, Room 3092, Harvard University with bulk chemical composition and extractable ion and trace metals on co-collected samples linking nitrate - came from air masses originating over the Mediterranean Sea (34%), Western Europe (20%) and the local