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1

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

SciTech Connect

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.

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

1993-04-01

2

Nitrates  

MedlinePLUS

... prescription instructions. Why do I need to take nitrates? Nitrates are used to treat the chest pain associated ... symptoms of congestive heart failure (CHF) . How do nitrates work? Nitrates are a vasodilator . Vasodilators widen (dilate) ...

3

Nitrate Protocol  

NSDL National Science Digital Library

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.

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

2003-08-01

4

Nitrate reduction  

DOEpatents

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

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

2000-01-01

5

Electroless deposition process for zirconium and zirconium alloys  

DOEpatents

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.

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

1981-01-01

6

Electroless deposition process for zirconium and zirconium alloys  

DOEpatents

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.

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

1981-08-18

7

Organic derivatives of zirconium phosphate  

E-print Network

zirconium phosphate as for n zirconium phosphate, The unit cell dimensions were determined by electron diffraction to be a = 5. 376 + 0. 002 A, b 6 . 636 + 0 . 004 A, c = 24 . 56 + 0 . 01 X, and 0 8 = 93. 94 + 0. 05' [9] . The interlayer spacing is 12. 3... of ethylene oxide on the fact that it esterifies phosphoric acid. He placed 0. 3 g samples of Y-zirconium phosphate into glass tubes with 40 ml of ethylene oxide solutions ranging in concentration from 0. 5 M to 5 M. These mixtures were shaken for varying...

Fine, Steven Beryl

2012-06-07

8

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

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

9

21 CFR 181.33 - Sodium nitrate and potassium nitrate.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Sodium nitrate and potassium nitrate. 181.33 Section 181.33 Food and Drugs...Prior-Sanctioned Food Ingredients § 181.33 Sodium nitrate and potassium nitrate. Sodium nitrate and...

2013-04-01

10

21 CFR 181.33 - Sodium nitrate and potassium nitrate.  

...2014-04-01 2014-04-01 false Sodium nitrate and potassium nitrate. 181.33 Section 181.33 Food and Drugs...Prior-Sanctioned Food Ingredients § 181.33 Sodium nitrate and potassium nitrate. Sodium nitrate and...

2014-04-01

11

21 CFR 181.33 - Sodium nitrate and potassium nitrate.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Sodium nitrate and potassium nitrate. 181.33 Section 181.33 Food and Drugs...Prior-Sanctioned Food Ingredients § 181.33 Sodium nitrate and potassium nitrate. Sodium nitrate and...

2012-04-01

12

Complexometric determination of aluminium, zirconium, and hafnium  

Microsoft Academic Search

Methods for the complexometric titration of aluminium, zirconium and hafnium are described using pyrocatechol violet as indicator. The EDTA titration of zirconium and hafnium is performed in acid medium and that of aluminium in a solution buffered with acetate.

I. Hazan; F. Feik; J. Korkisch

1965-01-01

13

Transformation superplasticity of zirconium  

SciTech Connect

A tensile strain of 270% was achieved for coarse-grained zirconium subjected to transformation superplasticity condition, where strain increments are accumulated upon repeated thermal cycling around the allotropic transformation temperature under the biasing effect of a uniaxial tensile stress. The strain increment per cycle was found to consist of two equal contributions from transformations on heating and cooling and to increase linearly with the applied stress. The measured strain increments are in good quantitative agreement with predictions based on the average internal stress during the transformation, which was determined independently from experimental transformation times. As the cycling frequency is raised, the average strain rate increases (a maximum value of 1.3 {times} 10{sup {minus}4} s{sup {minus}1} was measured), but the strain increment per cycle decreases above a critical cycling frequency, for which the sample gage section undergoes only a partial phase transformation. The resulting reduction in internal mismatch and increase in internal stress are modeled using the experimental observation that {beta}-Zr deforms by a mixture of diffusional and dislocation creep in the stress range of interest.

Zwigl, P. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Materials Science and Engineering; Dunand, D.C. [Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering

1998-10-01

14

Ablation Resistant Zirconium and Hafnium Ceramics  

NASA Technical Reports Server (NTRS)

High temperature ablation resistant ceramic composites have been made. These ceramics are composites of zirconium diboride and zirconium carbide with silicon carbide, hafnium diboride and hafnium carbide with silicon carbide and ceramic composites which contain mixed diborides and/or carbides of zirconium and hafnium. along with silicon carbide.

Bull, Jeffrey (Inventor); White, Michael J. (Inventor); Kaufman, Larry (Inventor)

1998-01-01

15

ZIRCONIUM AND HAFNIUM--1999 86.1 ZIRCONIUM AND HAFNIUM  

E-print Network

of the mining and processing of heavy-mineral sands for the titanium minerals, ilmenite and rutile, or tin to produce cubic zirconia, a diamond and colored gemstone simulant. Zirconium is used in nuclear fuel as a recently opened mining operation in Virginia continued to scale-up production. In 1999, production

16

ZIRCONIUM AND HAFNIUM--2001 86.1 ZIRCONIUM AND HAFNIUM  

E-print Network

are contained in zircon at a ratio of about 50:1. Zircon is a coproduct or byproduct of the mining is processed to produce cubic zirconia, a diamond and colored gemstone simulant. Zirconium metal is used of domestic operations. In 2001, the two domestic zircon producers, which have three mining and processing

17

ZIRCONIUM AND HAFNIUM--1998 86.1 ZIRCONIUM AND HAFNIUM  

E-print Network

of the mining and processing of heavy-mineral sands for the titanium minerals, ilmenite and rutile, or tin the diamond simulant, cubic zirconia. Zirconium is used in nuclear fuel cladding, chemical piping in corrosive. Domestic production of zircon increased as a new mine in Virginia came online. Production of milled zircon

18

Morphologies of uranium and uranium zirconium electrodeposits  

NASA Astrophysics Data System (ADS)

Uranium and uranium-zirconium electrodeposits produced in the Fuel Cycle Facility at Argonne National Laboratory-West were examined using standard metallurgical techniques. Substantial differences in the morphologies of the two types of deposits were observed. Samples from pure uranium deposits were comprised of chains of uranium crystals with a characteristic rhomboidal shape, while the morphologies of samples from deposits containing zirconium in excess of approximately 0.5 wt% 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.

Totemeier, Terry C.; Mariani, Robert D.

1997-12-01

19

Electrochemical process for zirconium alloy recycling  

SciTech Connect

This patent describes a method of separating nickel from zirconium for recycling nickel-containing zirconium alloy. It comprises: placing the nickel-containing zirconium in a molten alt bath at 500{degrees} to about 722{degrees} C. with the molten salt in the molten salt bath consisting essentially of a mixture of 0 to about 46.5 mole % lithium fluoride, about 11.5 to about 40 mole % sodium fluoride and potassium fluoride to produce a molten salt bath containing dissolved zirconium and dissolved nickel; electrochemically plating the nickel from the molten salt bath at a voltage sufficient to plate nickel but less than the voltage to plate zirconium to provide an essentially nickel-free molten salt bath; and electrochemically plating the zirconium from the essentially nickel-free molten salt bath to provide an essentially nickel-free zirconium.

Snyder, T.S.; Stoltz, R.A.; Zuckerbrod, D.

1990-05-08

20

Alkali metal nitrate purification  

DOEpatents

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.

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

1986-02-04

21

Spectrophotometric titration of zirconium in siliceous materials.  

PubMed

An accurate and selective complexometric titration procedure based upon a spectrophotometrically detected end-point has been developed for the determination of zirconium in glasses, glass-ceramics and refractories. A p-bromomandelic acid separation step for zirconium imparts excellent selectivity to the procedure. The method is particularly important for the 1-5% concentration range where a simple, accurate and selective method for the determination of zirconium has been lacking. PMID:18962344

Sugawara, K F; Su, Y S; Strzegowski, W R

22

Synthesis and formation process of zirconium dioxide nanorods  

NASA Astrophysics Data System (ADS)

Crystalline zirconium dioxide nanorods have been prepared by a simple hydrothermal process using zirconium hydroxide as the zirconium raw material. Zirconium dioxide nanorods are composed of monoclinic zirconium dioxide phase, which has been confirmed by the X-ray diffraction analysis. Electron microscopy observations show that the zirconium dioxide nanorods have a single crystal structure, with the rod diameter of less than 100 nm and length of 1-2 ?m. Hydrothermal temperature and reaction time play essential roles in the formation and growth of the zirconium dioxide nanorods. Nucleation and crystal growth process are proposed to explain the formation and growth of the zirconium dioxide nanorods.

Pei, L. Z.; Xie, Y. K.; Pei, Y. Q.; Yuan, C. Z.

2013-04-01

23

Comparison of sodium zirconium phosphate and Synroc matrices for immobilization of high-level waste  

SciTech Connect

The aims of the present work were to investigate possible compatibility between sodium zirconium phosphate (NZP) and Synroc titanate phases, to prepare NZP-based waste forms by hot-pressing rather than sintering, and to investigate the incorporation in NZP of (a) Cs/Sr as simulated heat-generating nuclides; (b) simulated actinides; and (c) simulated Purex waste. The NZP samples were prepared by methods similar to those used for Synroc. The precursor NZP phase was formed from tetrabutyl zirconate Zr(OC{sub 4}H{sub 9}){sub 4}, sodium nitrate, and 85% orthophosphoric acid. Simulated waste nitrate solutions were then mixed with the liquid precursor. After stir drying of the precursor, calcination was carried out at 700{degree}C to remove nitrates and organics.

Zyryanov, V.N. [Inst. of Experimental Mineralogy, Chernogolovka (Russian Federation); Vance, E.R. [Australian Nuclear Science and Technology Organization (ANSTO), Menai (Australia). Materials Division

1996-12-31

24

Cylodextrin Polymer Nitrate  

NASA Technical Reports Server (NTRS)

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

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

2000-01-01

25

Thermochemical nitrate destruction  

DOEpatents

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.

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

1992-01-01

26

Nitrate content and nitrate reductase activity in Rumex obtusifolius L  

Microsoft Academic Search

The aim of this work was to investigate the effect of nitrogen starvation and subsequent fentilization with nitrate or ammonium on nitrate content and nitrate reductase activity of Rumex obtusifolius L. under natural conditions.

A. Melzer; G. Gebauer; H. Rehder

1984-01-01

27

Method of making crack-free zirconium hydride  

DOEpatents

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.

Sullivan, Richard W. (Denver, CO)

1980-01-01

28

Drinking Water Problems: Nitrates  

E-print Network

High levels of nitrates in drinking water can be harmful for very young infants and susceptible adults. This publication explains how people are exposed to nitrates, what health effects are caused by them in drinking water and how to remove them....

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

2008-03-28

29

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

...Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126.28 Navigation and...

2014-07-01

30

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

Code of Federal Regulations, 2013 CFR

...Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126.28 Navigation and...

2013-07-01

31

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

Code of Federal Regulations, 2011 CFR

...Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126.28 Navigation and...

2011-07-01

32

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

Code of Federal Regulations, 2012 CFR

...Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126.28 Navigation and...

2012-07-01

33

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

Code of Federal Regulations, 2010 CFR

...Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126.28 Navigation and...

2010-07-01

34

Thermodynamics of the uranium-zirconium system  

NASA Astrophysics Data System (ADS)

Renewed interest in metallic fuel for nuclear reactors has prompted new studies of the thermodynamics and phase equilibria in binary alloys containing uranium, plutonium, and zirconium so that the ternary phase diagram might be calculated. An analysis of the uranium-zirconium alloy system has been performed. Thermodynamic functions for all existing uranium-zirconium phases have been derived and a phase diagram was calculated. These results are compared with the available thermodynamic data and accepted phase diagrams and general agreement was found. Disagreements generally occurred where experimental data were sparse and when previously drawn phase boundaries were found to be inconsistent with theory.

Leibowitz, L.; Blomquist, R. A.; Pelton, A. D.

1989-09-01

35

SOIL NITRATE TESTS FOR WISCONSIN  

E-print Network

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

Balser, Teri C.

36

Thermochemical nitrate reduction  

SciTech Connect

A series of preliminary experiments was conducted directed at thermochemically converting nitrate to nitrogen and water. Nitrates are a major constituent of the waste stored in the underground tanks on the Hanford Site, and the characteristics and effects of nitrate compounds on stabilization techniques must be considered before permanent disposal operations begin. For the thermochemical reduction experiments, six reducing agents (ammonia, formate, urea, glucose, methane, and hydrogen) were mixed separately with {approximately}3 wt% NO{sub 3}{sup {minus}} solutions in a buffered aqueous solution at high pH (13); ammonia and formate were also mixed at low pH (4). Reactions were conducted in an aqueous solution in a batch reactor at temperatures of 200{degrees}C to 350{degrees}C and pressures of 600 to 2800 psig. Both gas and liquid samples were analyzed. The specific components analyzed were nitrate, nitrite, nitrous oxide, nitrogen, and ammonia. Results of experimental runs showed the following order of nitrate reduction of the six reducing agents in basic solution: formate > glucose > urea > hydrogen > ammonia {approx} methane. Airnmonia was more effective under acidic conditions than basic conditions. Formate was also effective under acidic conditions. A more thorough, fundamental study appears warranted to provide additional data on the mechanism of nitrate reduction. Furthermore, an expanded data base and engineering feasibility study could be used to evaluate conversion conditions for promising reducing agents in more detail and identify new reducing agents with improved performance characteristics.

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

1992-09-01

37

ZIRCONIUM OXIDE NANOSTRUCTURES PREPARED BY ANODIC OXIDATION  

SciTech Connect

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.

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

2008-01-01

38

Synthesis of zirconium oxide nanoparticle by sol-gel technique  

SciTech Connect

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

Lim, H. S.; Ahmad, A.; Hamzah, H. [School of Chemical Science and Food Technology, Faculty of Science and Technology, National University of Malaysia, 43600 Bangi (Malaysia)

2013-11-27

39

Low-cycle fatigue of cold-press-welded zirconium  

Microsoft Academic Search

The behavior of cold-press welding as regards low-cycle fatigue on ; zirconium- zirconium joints was examined. Alternating torsion tests were carried ; out with constant strain amplitudes at room temperature on butt-welded and ; nonwelded zirconium samples (reactor-grade, annealed). During the tests, the ; torsional moment and the change in sample length were continually recorded. The ; lifetime until rupture

K. T. Rie; J. Ruge

1973-01-01

40

Processing fissile material mixtures containing zirconium and/or carbon  

DOEpatents

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.

Johnson, Michael Ernest; Maloney, Martin David

2013-07-02

41

Nitrate uptake and nitrate reduction in synchronous Chlorella  

Microsoft Academic Search

Nitrate uptake was followed continuously in cultures of Chlorella sorokiniana using ionsensitive electrodes. During the lifecycle of the synchronous cell cultures, a drastic increase occurred in the first hour after the onset of the light. Nitrate uptake rate was shown to be dependent on illumination intensity, nitrate concentration, and temperature. These results point to an energy-linked uptake process. From the

Rudolf Tischner; Harald Lorenzen

1979-01-01

42

Review of zirconium-zircaloy pyrophoricity  

SciTech Connect

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.

Cooper, T.D.

1984-11-01

43

ZIRCONIUM AND HAFNIUM (Data in metric tons of zirconium oxide (ZrO ) equivalent, unless otherwise noted)2  

E-print Network

194 ZIRCONIUM AND HAFNIUM (Data in metric tons of zirconium oxide (ZrO ) equivalent, unless, and sandblasting. The largest market for hafnium metal is an addition in superalloys. Salient Statistics) 837 884 836 929 1,4002 Zirconium oxide (ZrO content) 2,400 4,370 5,240 4,220 4,0002 2 Hafnium

44

Structural and electrical properties of zirconium doped yttrium oxide nanostructures  

NASA Astrophysics Data System (ADS)

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.

Bahari, Ali; Ebrahimzadeh, Masoud; Gholipur, Reza

2014-04-01

45

7, 55535593, 2007 Nitrate aerosols  

E-print Network

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

Paris-Sud XI, Université de

46

Influence of zirconium doping on the activities of zirconium and iodine co-doped titanium dioxide in the decolorization of methyl orange under visible light irradiation  

NASA Astrophysics Data System (ADS)

Zirconium and iodine co-doped titanium dioxide (Zr-I-TiO 2) was prepared by the hydrolysis of tetrabutyl titanate, premixed with zirconium nitrate in an iodic acid aqueous solution, followed by calcination in air. The structure and properties of the resultant catalyst powders were characterized by X-ray diffraction, the Brunauer-Emmett-Teller method, X-ray photoelectron spectroscopy, transmission electron microscopy, and UV-vis absorption spectroscopy. The catalytic activity of the catalyst was evaluated by monitoring the photocatalytic decolorization of methyl orange under visible light irradiation. The results showed that the activities of Zr-I-TiO 2 catalysts were higher than that of TiO 2 doped with iodine alone (I-TiO 2), and the optimal doping concentration in the Zr-I-TiO 2 calcined at 400 °C was determined to be about 0.05 (molar ratio of Zr:Ti). In addition, the photocatalytic activity of Zr-I-TiO 2 calcined at 400 °C was found to be significantly higher than that calcined at 500 or 600 °C. Based on the physico-chemical characterization, we concluded that the role of zirconium on the I-TiO 2 surface is to increase the number of reactive sites by generating a small crystal size and large surface area. The inhibition of electron-hole pair recombination, by trapping photo-generated electrons with Zr 4+, did not contribute markedly to the improved photocatalytic activity of Zr-I-TiO 2.

Song, Shuang; Hong, Fangyue; He, Zhiqiao; Wang, Hongyu; Xu, Xianghong; Chen, Jianmeng

2011-09-01

47

Zirconium Alloys in Nuclear Power Plants  

Microsoft Academic Search

The use of zirconium alloys for nuclear fuel and reactor internals in nuclear reactors is reviewed, with special attention to the mechanisms that can limit fuel burnup extensions in light water reactors, such as corrosion and hydriding and irradiation growth and creep. Recent techniques for studying these processes open the possibility that they can be understood mechanistically such that alloys

A. T. Motta

48

Purification of alkali metal nitrates  

DOEpatents

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.

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

1985-05-14

49

Zirconium and hafnium in meteorites  

NASA Astrophysics Data System (ADS)

The ratio of the two refractory trace elements zirconium (Zr) and hafnium (Hf) in meteorites has been proposed to be uniform. The most precise value available is 34.3+/-0.2 (1?). It was obtained by isotope dilution ICP-MS applied to 15 chondrites, most of which were carbonaceous chondrites, and six achondrites. We reinvestigated the case and determined Zr/Hf ratios of a broad spectrum of meteoritic samples via laser ablation ICP-MS. Our sample suite comprised 29 chondrites and five achondrites. The main objective of the study was two-fold: we intended to verify the accuracy and precision of a relatively fast and inexpensive sample preparation method combined with expeditious laser ablation ICP-MS techniques. Furthermore, we were looking into the possibility of systematic fine-scale Zr/Hf variations among bulk meteoritic matter of different classes. The applied fusion technique together with laser ablation ICP-MS turned out to be well suited to determine relative refractory trace element abundances. Absolute Zr/Hf ratios yield uncertainties of approximately 4% (1?). As opposed to the most recent findings, we observed variable Zr/Hf ratios in different meteorites ranging from approximately 28 to approximately 38. Our value for Orgueil (CI1) is 34.0+/-0.3 (1?). Including literature data, we propose a solar system value of 34.1+/-0.3. Our data also suggest that H chondrites tend to exhibit higher Zr/Hf ratios (average of 35.6+/-0.5 [1?]) while EL6 chondrites rather show low values (average of 30.8+/-0.6 [1?]). In addition to examining Zr/Hf ratios, we also explored the content of refractory major elements in different meteorite groups. Here, we found that EL6 chondrites often show very low Ca/Al ratios. The CI1 value for CaO/Al2O3 is 0.804. EL6 chondrites, however, display ratios as low as approximately 0.3. While the variation in Zr/Hf can be explained by fractional condensation processes in the early solar nebula, the observed low Ca/Al ratios in EL6 chondrites are probably attributable to deficits in oldhamite (CaS).

Patzer, Andrea; Pack, Andreas; Gerdes, Axel

2010-07-01

50

Ammonium nitrate explosive systems  

DOEpatents

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.

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

1981-01-01

51

Ammonium nitrate explosive systems  

SciTech Connect

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.

Coburn, M.D.; Stinecipher, M.M.

1981-11-17

52

Nitrate content and nitrate reductase activity in Rumex obtusifolius L  

Microsoft Academic Search

With Rumex obtusifolius L., the influence of some environmental conditions on nitrate uptake and reduction were investigated. Nitrate concentrations of plant material were determined by HPLC, the activity of nitrate reductase by an “in vivo” test. As optimal incubation medium, a buffer containing 0.04 M KNO3; 0.25 M KH2PO4; 1.5% propanol (v\\/v); pH 8.0 was found. Vacuum infiltration caused an

G. Gebauer; A. Melzer; H. Rehder

1984-01-01

53

Bismuth nitrate pentahydrate-induced novel nitration of eugenol  

PubMed Central

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

2011-01-01

54

40 CFR 421.330 - Applicability: Description of the primary zirconium and hafnium subcategory.  

Code of Federal Regulations, 2012 CFR

...Applicability: Description of the primary zirconium and hafnium subcategory...NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Primary Zirconium and Hafnium Subcategory...Applicability: Description of the primary zirconium and hafnium...

2012-07-01

55

40 CFR 421.330 - Applicability: Description of the primary zirconium and hafnium subcategory.  

Code of Federal Regulations, 2011 CFR

...Applicability: Description of the primary zirconium and hafnium subcategory...NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Primary Zirconium and Hafnium Subcategory...Applicability: Description of the primary zirconium and hafnium...

2011-07-01

56

40 CFR 421.330 - Applicability: Description of the primary zirconium and hafnium subcategory.  

Code of Federal Regulations, 2010 CFR

...Applicability: Description of the primary zirconium and hafnium subcategory...NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Primary Zirconium and Hafnium Subcategory...Applicability: Description of the primary zirconium and hafnium...

2010-07-01

57

40 CFR 421.330 - Applicability: Description of the primary zirconium and hafnium subcategory.  

Code of Federal Regulations, 2013 CFR

...Applicability: Description of the primary zirconium and hafnium subcategory...NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Primary Zirconium and Hafnium Subcategory...Applicability: Description of the primary zirconium and hafnium...

2013-07-01

58

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

59

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

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

2014-07-01

60

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

Code of Federal Regulations, 2012 CFR

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

2012-07-01

61

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

62

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

Code of Federal Regulations, 2011 CFR

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

2011-07-01

63

Manufacturing process to reduce large grain growth in zirconium alloys  

DOEpatents

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.

Rosecrans, P.M.

1984-08-01

64

Effects of titanium and zirconium on iron aluminide weldments  

SciTech Connect

When gas-tungsten arc welded, iron aluminides form a coarse fusion zone microstructure which is susceptible to hydrogen embrittlement. Titanium inoculation effectively refined the fusion zone microstructure in iron aluminide weldments, but the inoculated weldments had a reduced fracture strength despite the presence of a finer microstructure. The weldments fractured by transgranular cleavage which nucleated at cracked second phase particles. With titanium inoculation, second phase particles in the fusion zone changed shape and also became more concentrated at the grain boundaries, which increased the particle spacing in the fusion zone. The observed decrease in fracture strength with titanium inoculation was attributed to increased spacing of second phase particles in the fusion zone. Current research has focused on the weldability of zirconium- and carbon-alloyed iron aluminides. Preliminary work performed at Oak Ridge National Laboratory has shown that zirconium and carbon additions affect the weldability of the alloy as well as the mechanical properties and fracture behavior of the weldments. A sigmajig hot cracking test apparatus has been constructed and tested at Colorado School of Mines. Preliminary characterization of hot cracking of three zirconium- and carbon-alloyed iron aluminides, each containing a different total concentration of zirconium at a constant zirconium/carbon ratio of ten, is in progress. Future testing will include low zirconium alloys at zirconium/carbon ratios of five and one, as well as high zirconium alloys (1.5 to 2.0 atomic percent) at zirconium/carbon ratios of ten to forty.

Mulac, B.L.; Edwards, G.R. [Colorado School of Mines, Golden, CO (United States). Center for Welding, Joining, and Coatings Research; Burt, R.P. [Alumax Technical Center, Golden, CO (United States); David, S.A. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

1997-12-01

65

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

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. 176.410 Section 176.410 Transportation...176.410 Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. (a) This...

2012-10-01

66

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

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. 176.410 Section 176.410 Transportation...176.410 Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. (a) This...

2010-10-01

67

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

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. 176.410 Section 176.410 Transportation...176.410 Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. (a) This...

2013-10-01

68

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

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. 176.410 Section 176.410 Transportation...176.410 Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. (a) This...

2011-10-01

69

Zirconium induced physiological alterations in wheat seedlings  

Microsoft Academic Search

The effects of zirconium ascorbate (Zr-ASC), a water-soluble complex of Zr, were examined on wheat seedlings (Triticum aestivum L. cv. MV. 20). Hydroponically grown plants were exposed to 10, 33, 55, 100 and 550 ”M Zr-ASC (Zr10, Zr33etc.). After 9 d of treatment inhibition of germination, retarded root and shoot growth, and increased activities of antioxidant enzymes (guaiacol peroxidase, ascorbate

M. Fodor; A. Hegedus; E. Stefanovits-Banyai

2005-01-01

70

Fluorometric determination of zirconium in minerals  

USGS Publications Warehouse

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.

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

1951-01-01

71

Nitrate formation in atmospheric aerosols  

Microsoft Academic Search

Equilibrium nitrate levels in aqueous solution in the presence of sodium chloride, nitric oxide, nitrogen dioxide, sulfur dioxide, carbon dioxide, ammonia, and sulfuric acid are calculated. Nitrate levels in solution are of the order of those observed in the atmosphere when the gaseous concentrations are at typical urban levels. Sulfate levels in such solutions are predicted to be relatively low

Ann E. Orel; John H. Seinfeld

1977-01-01

72

Nitrate assimilation in Lotus japonicus  

Microsoft Academic Search

This paper summarizes some recent advances in the understanding of nitrate assimilation in the model legume Lotus japonicus. First, different types of experimental evidence are presented that emphasize the importance of the root in the nitrate-reducing assimilatory processes in this plant. Secondly, the main results from an ethyl methanesulphonate muta- genesis programme are presented. In this programme, chlorate-resistant and photorespiratory

Antonio J. Marquez; Marco Betti; Margarita Garcia-Calderon; Peter Pal' ove-Balang; Pedro Diaz; Jorge Monza

2005-01-01

73

Evaluation of nitrate destruction methods  

SciTech Connect

A wide variety of high nitrate-concentration aqueous mixed [radioactive and Resource Conservation and Recovery Act (RCRA) hazardous] wastes are stored at various US Department of Energy (DOE) facilities. These wastes will ultimately be solidified for final disposal, although the waste acceptance criteria for the final waste form is still being determined. Because the nitrates in the wastes will normally increase the volume or reduce the integrity of all of the waste forms under consideration for final disposal, nitrate destruction before solidification of the waste will generally be beneficial. This report describes and evaluates various technologies that could be used to destroy the nitrates in the stored wastes. This work was funded by the Department of Energy`s Office of Technology Development, through the Chemical/Physical Technology Support Group of the Mixed Waste Integrated Program. All the nitrate destruction technologies will require further development work before a facility could be designed and built to treat the majority of the stored wastes. Several of the technologies have particularly attractive features: the nitrate to ammonia and ceramic (NAC) process produces an insoluble waste form with a significant volume reduction, electrochemical reduction destroys nitrates without any chemical addition, and the hydrothermal process can simultaneously treat nitrates and organics in both acidic and alkaline wastes. These three technologies have been tested using lab-scale equipment and surrogate solutions. At their current state of development, it is not possible to predict which process will be the most beneficial for a particular waste stream.

Taylor, P.A. [Oak Ridge National Lab., TN (United States); Kurath, D.E.; Guenther, R. [Pacific Northwest Lab., Richland, WA (United States)

1993-03-30

74

Nitrate losses from disturbed ecosystems  

Microsoft Academic Search

A systematic examination of nitrogen cycling in disturbed forest ecosystems demonstrates that eight processes, operating at three stages in the nitrogen cycle, could delay or prevent solution losses of nitrate from disturbed forests. An experimental and comparative study of nitrate losses from trenched plots in 19 forest sites throughout the United States suggests that four of these processes (nitrogen uptake

P. M. Vitousek; J. R. Gosz; C. C. Grier; J. M. Melillo; W. A. Reiners; R. L. Todd

1979-01-01

75

Catalyzed reduction of nitrate in aqueous solutions.  

National Technical Information Service (NTIS)

Sodium nitrate and other nitrate salts in wastes is a major source of difficulty for permanent disposal. Reduction of nitrate using aluminum metal has been demonstrated, but NH(sub 3), hydrazine, or organic compounds containing oxygen would be advantageou...

P. A. Haas

1994-01-01

76

NITRATE LEACHING IN FLORIDA URBAN ENVIRONMENTS  

E-print Network

NITRATE LEACHING IN FLORIDA URBAN ENVIRONMENTS Michael Atkin Non-Thesis Research Paper Advisor: Dr....................................................................................3 Background- Nitrate Behavior in Soil and Florida Groundwater Vulnerability.......4 Urban Ecology in Urban Areas and Nitrate Reduction Strategies.......13 Conclusion

Ma, Lena

77

76 FR 70366 - Ammonium Nitrate Security Program  

Federal Register 2010, 2011, 2012, 2013

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

2011-11-14

78

76 FR 47238 - Ammonium Nitrate From Russia  

Federal Register 2010, 2011, 2012, 2013

...731-TA-856; Second Review] Ammonium Nitrate From Russia Determination On the basis...the antidumping duty order on ammonium nitrate from Russia would be likely to lead to...4249 (August 2011), entitled Ammonium Nitrate from Russia: Investigation No....

2011-08-04

79

76 FR 11273 - Ammonium Nitrate From Russia  

Federal Register 2010, 2011, 2012, 2013

...731-TA-856 (Second Review)] Ammonium Nitrate From Russia AGENCY: United States International...the suspended investigation on ammonium nitrate from Russia...the suspended investigation on ammonium nitrate from Russia would be likely to lead...

2011-03-01

80

PHYSICAL METALLURGY AND PROPERTIES OF ZIRCONIUM-URANIUM ALLOYS  

Microsoft Academic Search

The constitution and transformation kinetic behavior of uranium-; zirconium alloys are presented. The system is characterized by complete solid ; solution between gamma uranium and beta zirconium at elevated temperatures and by ; the intermediate hexagonal epsilon phase which forms from this solution at about ; 600 deg C and contains approximately 50 wt.% uranium. Oxygen and nitrogen have a

A. A. Bauer; S. Kass; K. M. Goldman

1958-01-01

81

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

E-print Network

Zirconium oxide ZrO2 is a promising high-dielectric constant replacement for SiO2 in future microelectronic. 6 and produce high quality dielectric films.7 Using H2O as oxygen source, the expected ALD reaction- tons and desorb as HL. The kinetics of this elimination reac- tion will be determined by the relative

82

The role of subsurface oxygen in the local oxidation of zirconium and zirconium nitride thin films  

Microsoft Academic Search

This paper discusses the growth kinetics of nanometer scale oxide structures grown by atomic force microscope (AFM) assisted lithography. The addition of nitrogen into the sputtering gas during zirconium deposition results in a crystalline ZrN material with oxygen held in solid solution. The diffusion rate of oxygen is high through the crystalline material, allowing it to participate in local anodization

N. Farkas; G. Zhang; K. M. Donnelly; E. A. Evans; R. D. Ramsier; J. A. Dagata

2004-01-01

83

Anodic Electrodeposition of Highly Oriented Zirconium Phosphate and Polyaniline-Intercalated Zirconium Phosphate  

E-print Network

be inter- calated after deposition to give inorganic-organic composites, the method does not offer much-zirconium phosphate with a conducting polymer. Introduction Polymer-inorganic hybrids with lamellar structures can be synthesized by intercalation, ion-exchange, and exfoliation. For bulk-phase materials, intercalation and ion

84

Corrosion resistance of zirconium and zirconium-titanium alloy in hot nitric acid  

Microsoft Academic Search

Since zirconium (Zr) has superior corrosion resistance to concentrated nitric acid (HNO3) at elevated temperature, it has been successfully used as a material for chemical plants to produce HNO3 or spent nuclear fuel reprocessing plants. However, the occurrence of stress corrosion cracking (SCC) has recently been reported in hot nitric acid conditions. The necessary conditions for SCC in Zr, and

Hiroo Nagano; Haruhiko Kajimura; Kazuo Yamanaka

1995-01-01

85

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

NASA Astrophysics Data System (ADS)

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.

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

2013-04-01

86

Diffusion of hydrogen in zirconium foil  

SciTech Connect

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

Schur, D.V.; Pishuk, V.K.; Adejev, V.M. [Inst. of Hydrogen and Solar Energy, Kiev (Ukraine); Zaginaichenko, S.Y. [UAS, Kiev (Ukraine). Inst. for Problems of Materials Science

1998-12-31

87

Creep Behavior of Hydrogenated Zirconium Alloys  

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

88

Nitrate and Prussic Acid Poisoning  

E-print Network

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....

Stichler, Charles; Reagor, John C.

2001-09-05

89

Nitrate Removal in NITREXTM Permeable Reactive Barriers  

E-print Network

Nitrate Removal in NITREXTM Permeable Reactive Barriers: Investigating Denitrification Using a 15 (particularly of nitrate) to aquatic systems is a growing problem. The NITREXTM Permeable Reactive Barrier (PRB) is a system for removing nitrate in groundwater. We investigated the nitrate removal processes and hydrology

Vallino, Joseph J.

90

What Limits Nitrate Reduction in Leaves?  

Microsoft Academic Search

The observation that even drastic over- or underexpression of nitrate reductase (NR) has little effect on biomass production suggests that nitrate reduction in situ and extractable NR activity are not strictly coupled. Rates of nitrate reduction in detached spinach leaves are often, but not always, much lower than NR activity measured in leaf extracts under substrate (nitrate and NADH) saturation.

Werner M. Kaiser; Maria Stoimenova; Hui-Min Man

91

Studies of nitrate reductase in marine phytoplankton  

Microsoft Academic Search

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

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

1969-01-01

92

Viscosity of Molten Sodium Nitrate  

NASA Astrophysics Data System (ADS)

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

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

2006-11-01

93

Deliquescence, Efflorescence, and Water Activity in Ammonium Nitrate and Mixed Ammonium Nitrate/Succinic Acid Microparticles  

E-print Network

Deliquescence, Efflorescence, and Water Activity in Ammonium Nitrate and Mixed Ammonium Nitrate of ammonium nitrate/water and mixed ammonium nitrate/succinic acid/water microparticles. The water activity of ammonium nitrate microparticles is determined as a function of composition down to 12% relative humidity

94

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

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

95

Imbalance between vertical nitrate flux and nitrate assimilation on a continental shelf: Implications of nitrification  

Microsoft Academic Search

Nitrate assimilation and diapycnal nitrate flux were simultaneously determinedPresence of amoA indicated nitrification within the euphotic zoneNitrate-based new production can be overestimated by the nitrification

Takuhei Shiozaki; Ken Furuya; Hiroyuki Kurotori; Taketoshi Kodama; Shigenobu Takeda; Takahiro Endoh; Yutaka Yoshikawa; Joji Ishizaka; Takeshi Matsuno

2011-01-01

96

Electrochemical study of corrosion phenomena in zirconium alloys  

E-print Network

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

Treeman, Nicole M

2005-01-01

97

Separation of zirconium from hafnium by solvent extraction  

SciTech Connect

Separation of zirconium and hafnium by solvent extraction with a tertiary amine from sulfuric acid solution is improved by addition of water-soluble alpha -hydroxycarboxylic acid to the aqueous phase.

Macdonald, D.J.

1980-11-04

98

Extractive separation of uranium and zirconium sulfates by amines  

SciTech Connect

This paper describes an amine extraction process for zirconium and uranium separation. The behaviour of an extraction system containing uranium (VI) sulfate, zirconium (IV) sulfate, 0.2 and 0.5 M sulfuric acid (as the original aqueous phase), tertiary amine tri-n-lauryl- amine or primary amine Primene JMT in benzene (as the original organic phase) is discussed on the basis of equilibrium data. The measured dependences show that the degree of extraction of zirconium at the sulfuric acid concentration of 0.5 M and above is only slightly affected by a presence of uranium in solution. From this surprising behaviour it follows that zirconium may be employed for the displacement of uranium from the organic phase. This effect is more pronounced with the primary amine Primene JMT than with TLA. 29 refs., 4 figs., 1 tab.

Schroetterova, D.; Nekovar, P.; Mrnka, M. [Prague Inst. of Chemical Technology (Czechoslovakia)

1992-04-01

99

Modelling precipitation in zirconium niobium alloys  

NASA Astrophysics Data System (ADS)

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.

Robson, J. D.

2008-07-01

100

On the dynamic tensile strength of Zirconium  

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

101

Electrical conductivity of transition metal containing crystalline zirconium phosphate materials  

Microsoft Academic Search

?-Zirconium phosphate (?-ZrP) has been prepared in various transition metal containing forms, and their structure (identified by XRD), thermal behaviour and specific surface area were determined and their electrical resistivity was measured. On the basis of experimental data, the monoclinic cell parameters for Co(II), Ni(II), Cu(II), and Zn(II) containing crystalline zirconium phosphates were calculated. They showed characteristic thermal decomposition and

L Szirtes; J Megyeri; E Kuzmann; Z Klencsár

2001-01-01

102

[Glyceryl nitrates may cause hypertension].  

PubMed

The patient was an 82-year-old woman with orthostatism, who was administrated one normal dose of glyceryl nitrate as a part of a tilt table test. The following ten minutes after administration, a paradoxical and significant blood pressure response was registered in the form of a rise to 205/111 mmHg. The conclusion was that her response was a paradoxical response to glyceryl nitrate, orthostatism and a pathological response to massage of the carotid artery. This is the third reported case on paradoxical hypertension induced by glyceryl nitrates. It is speculated that dysfunction of the cerebral bloodflow autoregulation may be one of the causes of this phenomenon. PMID:21586249

Műrup, Peter; Levinsen, Tine Holbæk; Hovind, Peter

2011-05-16

103

Quercetin as colorimetric reagent for determination of zirconium  

USGS Publications Warehouse

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.

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

1953-01-01

104

Acetonyltriphenyl-phospho-nium nitrate  

PubMed Central

Crystals of the title salt, C21H20OP+·NO3 ?, are composed of acetonyltriphenyl­phospho­nium cations and nitrate anions that mainly inter­act through electrostatic forces. The P atom in the cation has a slightly distorted tetra­hedral environment, with C—P—C angles ranging from 104.79?(7) to 112.59?(6)°. The sum of O—N—O angles of the nitrate anion is 359.99°, reflecting its trigonal–planar character. C—H?O hydrogen bonds help to consolidate the crystal packing. PMID:23424568

Diop, Tidiane; Diop, Libasse; Kucerakova, Monika; Dusek, Michal

2013-01-01

105

Acetonyltriphenyl-phospho-nium nitrate.  

PubMed

Crystals of the title salt, C(21)H(20)OP(+)·NO(3) (-), are composed of acetonyltriphenyl-phospho-nium cations and nitrate anions that mainly inter-act through electrostatic forces. The P atom in the cation has a slightly distorted tetra-hedral environment, with C-P-C angles ranging from 104.79?(7) to 112.59?(6)°. The sum of O-N-O angles of the nitrate anion is 359.99°, reflecting its trigonal-planar character. C-H?O hydrogen bonds help to consolidate the crystal packing. PMID:23424568

Diop, Tidiane; Diop, Libasse; Ku?eráková, Monika; Dušek, Michal

2013-02-01

106

Nitrate Trends in Minnesota Rivers  

USGS Publications Warehouse

The objective of this study was to assess long-term trends (30 to 35 years) of flow-adjusted concentrations of nitrite+nitrate-N (hereinafter referred to as nitrate) in a way that would allow us to discern changing trends. Recognizing that these trends are commonly different from one river to another river and from one part of the state to another, our objective was to examine as many river monitoring sites across the state as possible for which sufficient long term streamflow and concentration data were available.

Wall, Dave; Christopherson, Dave; Lorenz, Dave; Martin, Gary

2013-01-01

107

Protection against oral and gastrointestinal diseases: Importance of dietary nitrate intake, oral nitrate reduction and enterosalivary nitrate circulation  

Microsoft Academic Search

Over the last 20 years, dietary nitrate has been implicated in the formation of methemoglobin and carcinogenic nitrosamines in humans. This has led to restrictions of nitrate and nitrite levels in food and drinking water. However, there is no epidemiological evidence for an increased risk of gastric and intestinal cancer in population groups with high dietary vegetable or nitrate intake.

Callum Duncan; Hong Li; Roelf Dykhuizen; Rennie Frazer; Peter Johnston; Gillian MacKnight; Lorna Smith; Kathryn Lamza; Hamish McKenzie; Les Batt; Denise Kelly; Michael Golden; Nigel Benjamin; Carlo Leifert

1997-01-01

108

Constructed Marshes for Nitrate Removal  

Microsoft Academic Search

Large numbers of free water surface treatment wetlands are in use for nitrate reduction. Target applications are field runoff, river and stream improvement, and enhancement of wastewater treatment plants. In total, an extensive database now exists, in many publications and operating reports. Microcosms and mesocosms are not included here because of the lack of transferability to design. A first-order areal

Robert H. Kadlec

2012-01-01

109

Constructed Marshes for Nitrate Removal  

Microsoft Academic Search

Large numbers of free water surface treatment wetlands are in use for nitrate reduction. Target applications are field runoff, river and stream improvement, and enhancement of wastewater treatment plants. In total, an extensive database now exists, in many publications and operating reports. Microcosms and mesocosms are not included here, because of lack of transferability to design. A first-order areal model

Robert H. Kadlec

2011-01-01

110

A Novel Chemical Nitrate Destruction Process  

SciTech Connect

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.

Dziewinski, J.; Marczak, S.

1999-03-01

111

Comparative Studies on Nitrate Reductase in Agrostemma githago Induced by Nitrate and Benzyladenine 12  

PubMed Central

NADH-nitrate reductase activity in excised embryos of Agrostemma githago develops in response to nitrate as well as benzyladenine. Induction of nitrate reductase by benzyladenine was much more susceptible to inhibition by a mixture of amino acid analogues and by cordycepin than induction by nitrate. In contrast, only induction of nitrate-nitrate reductase was decreased by chloramphenicol. NADH-cytochrome c reductase and reduced flavin mono-nucleotide-nitrate reductase activities were found to be associated with NADH-nitrate reductase and were induced by both nitrate and benzyladenine. When a partially purified enzyme sample was centrifuged in a linear 5 to 20% sucrose density gradient, a minor and a major band of NADH-cytochrome c reductase activity were observed. NADH-nitrate reductase cosedimented with the major band. The characteristics of nitrate-nitrate reductase and benzyl-adenine-nitrate reductase were compared by four methods but no differences could be detected: (a) Both enzymes sedimented with the same velocity during sucrose density gradient centrifugation. (b) Their distribution among fractions obtained by differential precipitation with (NH4)2SO4 was identical. (c) The elution profile of nitrate-nitrate reductase and benzyl-adenine-nitrate reductase after chromatography on diethyl-aminoethyl Sephadex A-25 columns showed no significant difference. (d) On polyacrylamide gel, the electrophoretic migration of the two enzymes was also identical. PMID:16658982

Dilworth, Machi Fukuyama; Kende, Hans

1974-01-01

112

Comparative Studies on Nitrate Reductase in Agrostemma githago Induced by Nitrate and Benzyladenine.  

PubMed

NADH-nitrate reductase activity in excised embryos of Agrostemma githago develops in response to nitrate as well as benzyladenine. Induction of nitrate reductase by benzyladenine was much more susceptible to inhibition by a mixture of amino acid analogues and by cordycepin than induction by nitrate. In contrast, only induction of nitrate-nitrate reductase was decreased by chloramphenicol.NADH-cytochrome c reductase and reduced flavin mono-nucleotide-nitrate reductase activities were found to be associated with NADH-nitrate reductase and were induced by both nitrate and benzyladenine. When a partially purified enzyme sample was centrifuged in a linear 5 to 20% sucrose density gradient, a minor and a major band of NADH-cytochrome c reductase activity were observed. NADH-nitrate reductase cosedimented with the major band.The characteristics of nitrate-nitrate reductase and benzyl-adenine-nitrate reductase were compared by four methods but no differences could be detected: (a) Both enzymes sedimented with the same velocity during sucrose density gradient centrifugation. (b) Their distribution among fractions obtained by differential precipitation with (NH(4))(2)SO(4) was identical. (c) The elution profile of nitrate-nitrate reductase and benzyl-adenine-nitrate reductase after chromatography on diethyl-aminoethyl Sephadex A-25 columns showed no significant difference. (d) On polyacrylamide gel, the electrophoretic migration of the two enzymes was also identical. PMID:16658982

Dilworth, M F; Kende, H

1974-12-01

113

High-speed deformation and fracture of the dioxide-zirconium ceramics and zirconium alumina concrete  

NASA Astrophysics Data System (ADS)

The results of dynamic tests of two refractory materials based on zirconium dioxide: three types of ceramics and barium-aluminate concrete. The ceramic specimens had various initial density and porosity and also differed by technology of manufacturing. Compression tests were carried out using the Kolsky technique and its updating - specimen in a rigid jacket. The dynamic stress-strain curves were obtained. The strong influence of sample's initial grain composition, mode of stressed-strained state and technologies of manufacturing of specimens onto ceramics mechanical properties is marked.

Bragov, A.; Kruszka, L.; Lomunov, A.; Konstantinov, A.; Lamzin, D.; Filippov, A.

2012-08-01

114

Nitrate toxicity in Siberian sturgeon ( Acipenser baeri)  

Microsoft Academic Search

Excess nitrate in aquaculture has traditionally been reduced by water exchange. Current trends in environmental regulation, however, are limiting the amount of water which may be consumed or discharged, reducing the ability to use large influxes of water to remediate excess nitrate. This will create significant challenges for the aquaculture community, as the etiology, effects and tolerable thresholds of nitrate

H. J. Hamlin

2006-01-01

115

3, 59195976, 2003 The nitrate aerosol  

E-print Network

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

Paris-Sud XI, Université de

116

8, 48114829, 2008 SOA and nitrate  

E-print Network

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

Paris-Sud XI, Université de

117

6, 14551480, 2006 Modelling of nitrate  

E-print Network

ACPD 6, 1455­1480, 2006 Modelling of nitrate particles G. Myhre and A. Grini Title Page Abstract Discussions Modelling of nitrate particles: importance of sea salt G. Myhre1,2 and A. Grini1 1 Department Correspondence to: G. Myhre (gunnar.myhre@geo.uio.no) 1455 #12;ACPD 6, 1455­1480, 2006 Modelling of nitrate

Boyer, Edmond

118

Spatial Inference of Nitrate Concentrations in Groundwater  

E-print Network

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

West, Mike

119

8, 1103911062, 2008 Nitrate in polar ice  

E-print Network

ACPD 8, 11039­11062, 2008 Nitrate in polar ice E. W. Wolff et al. Title Page Abstract Introduction Chemistry and Physics Discussions Reassessment of the factors controlling temporal profiles of nitrate Geosciences Union. 11039 #12;ACPD 8, 11039­11062, 2008 Nitrate in polar ice E. W. Wolff et al. Title Page

Paris-Sud XI, Université de

120

6, 1071310731, 2006 Nitrate photolysis on  

E-print Network

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

Paris-Sud XI, Université de

121

21 CFR 172.170 - Sodium nitrate.  

Code of Federal Regulations, 2012 CFR

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

2012-04-01

122

21 CFR 172.160 - Potassium nitrate.  

Code of Federal Regulations, 2013 CFR

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

2013-04-01

123

76 FR 62311 - Ammonium Nitrate Security Program  

Federal Register 2010, 2011, 2012, 2013

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

2011-10-07

124

Nitrate removal from drinking water -- Review  

Microsoft Academic Search

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,

Anoop Kapoor; T. Viraraghavan

1997-01-01

125

Efflux Of Nitrate From Hydroponically Grown Wheat  

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

126

21 CFR 172.160 - Potassium nitrate.  

Code of Federal Regulations, 2012 CFR

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

2012-04-01

127

21 CFR 172.160 - Potassium nitrate.  

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

2014-04-01

128

21 CFR 172.170 - Sodium nitrate.  

Code of Federal Regulations, 2013 CFR

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

2013-04-01

129

21 CFR 172.170 - Sodium nitrate.  

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

2014-04-01

130

DO ORGANIC FARMING PRACTICES REDUCE NITRATE LEACHING?  

Microsoft Academic Search

Agriculture is a contributor of nitrate to natural waters and there is concern about the excess nitrogen burden loadings from agriculture on natural waters. Agricultural practices that reduce nitrate leaching from arable land are needed. It is postulated by certain groups that organic farming practices reduce nitrate leaching among other environmental benefits. The objectives of this paper are: (1) to

Holger Kirchmann; Lars Bergström

2001-01-01

131

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

E-print Network

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

Mews, Paul Aaron

2009-05-15

132

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

Code of Federal Regulations, 2013 CFR

...Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415...Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate...

2013-10-01

133

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

Code of Federal Regulations, 2012 CFR

...Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415...Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate...

2012-10-01

134

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

Code of Federal Regulations, 2011 CFR

...Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415...Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate...

2011-10-01

135

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

Code of Federal Regulations, 2010 CFR

...Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415...Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate...

2010-10-01

136

Dissolved zirconium in the north Pacific Ocean  

SciTech Connect

Picomolar levels of dissolved Zr in seawater were measured using an analytical technique developed with a Chelex-100 extraction/concentration step and subsequent detection by isotope-dilution inductively-coupled-plasma mass spectrometry (ID-ICP-MS). Here the authors present the first vertical profile of Zr in the oceans, from the central-North Pacific, and a horizontal surface transect across the western Pacific. Dissolved Zr ranges from 12--95 pmol/kg in the surface waters then increases linearly with depth to a maximum of 300 pmol/kg in the deep water. The vertical profile shows a strong correlation with Si in the mid-waters, with higher Zr/Si ratios in the surface and bottom waters. There is evidence of both a bottom source and a coastal source of dissolved Zr to the oceans. A comparison with dissolved Ti and Be shows similar depth dependence, but an enrichment in Zr/Ti and a depletion in Zr/Be ratios in seawater relative to average crustal materials. Zirconium appears to have a reactivity intermediate between these two elements. 24 refs., 4 figs., 1 tab.

McKelvey, B.A.; Orians, K.J. (Univ. of British Columbia, Vancouver (Canada))

1993-08-01

137

Nitrated fatty acids: Synthesis and measurement  

PubMed Central

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

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

2012-01-01

138

Continuous flow nitration in miniaturized devices  

PubMed Central

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

2014-01-01

139

Apatite formation on bioactive zirconium metal prepared by chemical treatment.  

PubMed

Bioactive metallic materials, which can directly bond to living bone, are badly needed in dental and orthopedic implants for better long-term results. Forming a layer of bone-like apatite on the surface of the metal is one of the most promising methods to increase its bioactivity. This study creates a new chemical treatment for zirconium metal to induce apatite formation in a simulated body fluid (SBF), and analyzes the apatite layer by using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR). Zirconium samples were soaked in 10% CuCl2 aqueous solution at 80 degrees C for 72 hours, heat-treated at 500 degrees C for one hour and soaked in SBF for various periods. An apatite-like layer appeared on the zirconium surface as early as three days in SBF, and increased with immersion time. EDS and FTIR confirmed that the deposited layer was apatite. This implies that bioinert zirconium metal can become bioactive by forming an apatite layer in a simulated body fluid after a suitable chemical treatment. The ZrOOH+ hydrogel layer produced on the zirconium surface by CuCl2 and heat-treatments is thought to induce the apatite formation. PMID:12085656

Shi, Xinfeng; Hulbert, Samuel

2002-01-01

140

Experimental Study of Zirconium(IV) Extraction from Fluoride-Containing Acid Solutions  

Microsoft Academic Search

Zirconium(IV) extraction from acid solutions was studied, and the optimal parameters of the process were found. Extractants for zirconium(IV) recovery from nitric and sulfuric acid solutions in the presence of fluoride ions were selected. The distribution coefficients of zirconium(IV) and fluoride ion were determined.

I. A. Dibrov; D. E. Chirkst; T. E. Litvinova

2002-01-01

141

LIQUID-LIQUID EXTRACTION OF HAFNIUM FROM ZIRCONIUM BY TRIBUTYL PHOSPHATE  

Microsoft Academic Search

ABS>The removal of hafnium from zirconium is one of a number of ; operations required to produce high purity zirconium metal for use in nuclear ; reactors. Since the metallurgical operations involved in the production of ; zirconium must use the products of hafnium-removal processes, the choice of a ; process for hafnium removal must be integrated with subsequent metallurgical

G. H. Beyer; H. C. Peterson

1951-01-01

142

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

SciTech Connect

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.

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

143

Phase diagram of ammonium nitrate  

NASA Astrophysics Data System (ADS)

Ammonium Nitrate (AN) has often subjected to uses in improvised explosive devices, due to its wide availability as a fertilizer and its capability of becoming explosive with slight additions of organic and inorganic compounds. Yet, the origin of enhanced energetic properties of impure AN (or AN mixtures) is neither chemically unique nor well understood -resulting in rather catastrophic disasters in the past1 and thereby a significant burden on safety in using ammonium nitrates even today. To remedy this situation, we have carried out an extensive study to investigate the phase stability of AN at high pressure and temperature, using diamond anvil cells and micro-Raman spectroscopy. The present results confirm the recently proposed phase IV-to-IV' transition above 17 GPa2 and provide new constraints for the melting and phase diagram of AN to 40 GPa and 400 °C.

Dunuwille, M.; Yoo, C. S.

2014-05-01

144

Catalyzed reduction of nitrate in aqueous solutions  

SciTech Connect

Sodium nitrate and other nitrate salts in wastes is a major source of difficulty for permanent disposal. Reduction of nitrate using aluminum metal has been demonstrated, but NH{sub 3}, hydrazine, or organic compounds containing oxygen would be advantageous for reduction of nitrate in sodium nitrate solutions. Objective of this seed money study was to determine minimum conditions for reduction. Proposed procedure was batchwise heating of aqueous solutions in closed vessels with monitoring of temperatures and pressures. A simple, convenient apparatus and procedure were demonstrated for observing formation of gaseous products and collecting samples for analyses. The test conditions were 250{degree}C and 1000 psi max. Any useful reduction of sodium nitrate to sodium hydroxide as the primary product was not found. The nitrate present at pHs < 4 as HNO{sub 3} or NH{sub 4}NO{sub 3} is easily decomposed, and the effect of nitromethane at these low pHs was confirmed. When acetic acid or formic acid was added, 21 to 56% of the nitrate in sodium nitrate solutions was reduced by methanol or formaldehyde. With hydrazine and acetic acid, 73 % of the nitrate was decomposed to convert NaNO{sub 3} to sodium acetate. With hydrazine and formic acid, 36% of the nitrate was decomposed. If these products are more acceptable for final disposal than sodium nitrate, the reagents are cheap and the conversion conditions would be practical for easy use. Ammonium acetate or formate salts did not significantly reduce nitrate in sodium nitrate solutions.

Haas, P.A.

1994-08-01

145

Electrolytic production of uranous nitrate  

SciTech Connect

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.

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

1980-04-01

146

Material property correlations for the niobium-1% zirconium alloy  

E-print Network

(Member) John . Poston (Head of Department) K. Ted Harwig (Member) August 1989 Material Property Correlations for the Niobium-1% Zirconium Alloy. (August 1989) David James Senor, B, S. , Texas A8cM University Chair of Advisory Committee: Dr. K. L... (Member) John . Poston (Head of Department) K. Ted Harwig (Member) August 1989 Material Property Correlations for the Niobium-1% Zirconium Alloy. (August 1989) David James Senor, B, S. , Texas A8cM University Chair of Advisory Committee: Dr. K. L...

Senor, David James

2012-06-07

147

In-situ stabilization of radioactive zirconium swarf  

SciTech Connect

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

Hess, Clay C.

1997-12-01

148

Variant selection and transformation texture in zirconium alloy Excel  

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

149

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

SciTech Connect

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.

Cho, D. H.

1998-04-10

150

Fast photolysis of carbonyl nitrates from isoprene  

NASA Astrophysics Data System (ADS)

We show that photolysis is, by far, the major atmospheric sink of isoprene-derived carbonyl nitrates. Empirical evidence from published laboratory studies on the absorption cross sections and photolysis rates of ?-nitrooxy ketones suggests that the presence of the nitrate group (i) greatly enhances the absorption cross sections, and (ii) facilitates dissociation to a point that the photolysis quantum yield is close to unity, with O-NO2 dissociation as the likely major channel. On this basis, we provide new recommendations for estimating the cross sections and photolysis rates of carbonyl nitrates. The newly estimated photorates are validated using a chemical box model against measured temporal profiles of carbonyl nitrates in an isoprene oxidation experiment by Paulot et al. (2009). The comparisons for ethanal nitrate and for the sum of methacrolein- and methylvinylketone nitrates strongly supports our assumptions of large cross section enhancements and a near-unit quantum yield for these compounds. These findings have significant atmospheric implications, as carbonyl nitrates constitute an important component of the total organic nitrate pool over vegetated areas: the photorates of key carbonyl nitrates from isoprene are estimated to be typically between ~3 and 20 times higher than their sink due to reaction with OH in relevant atmospheric conditions. Moreover, since the reaction is expected to release NO2, photolysis is especially effective in depleting the total organic nitrate pool.

Müller, Jean-Francois; Peeters, Jozef; Stavrakou, Trisevgeni

2014-05-01

151

Nitrate deposition and impact of Adirondack streams  

SciTech Connect

Acidic deposition has a great impact on water chemistry and fish populations in the Adirondack region. Although the Clean Air Act Amendments of 1990 have resulted in some reductions of sulfur deposition, nitrate deposition has not yet been well controlled, and continues to impact aquatic resources. As part of the USEPA funded Episodic Response Project, four Adirondack headwater streams were intensively monitored over an 18 month period. Atmospheric deposition was also monitored at a centrally located station. The quantity of nitrate being deposited on the study watersheds was calculated based on monthly net deposition data, which ranged from 0.6 kg/ha/month to 3.6 kg/ha/month. These data were then compared to the monthly export of nitrate from the watershed in these streams. Nitrate concentrations were highest in the stream water during the spring snowmelt period prior to the time when forest vegetation actively utilizes nitrate. On an annual basis, the amount of nitrate that left the watershed via stream water was approximately equal to the amount that fell as nitrate deposition. These data are important in documenting the impact that nitrate has in acidifying Adirondack streams during the spring, which coincides with brook trout hatching. Control programs for nitrous oxide emissions are presently aimed at reducing ozone levels during the May--September period. These emissions control programs need to be expanded to also reduce nitrate deposition in the sensitive Adirondack region during the water and spring periods when nitrate deposition has its greatest impact on aquatic resources.

Simonin, H.A. [New York State Dept. of Environmental Conservation, Rome, NY (United States). Rome Field Station; Kretser, W. [New York State Dept. of Environmental Conservation, Ray Brook, NY (United States). Adirondack Lakes Survey Corp.

1995-12-31

152

An Electrolytic Method to Form Zirconium Hydride Phases in Zirconium Alloys with Morphologies Similar to Hydrides Formed in Used Nuclear Fuel  

E-print Network

AN ELECTROLYTIC METHOD TO FORM ZIRCONIUM HYDRIDE PHASES IN ZIRCONIUM ALLOYS WITH MORPHOLOGIES SIMILAR TO HYDRIDES FORMED IN USED NUCLEAR FUEL A Thesis by SAMUEL HOUSTON KUHR Submitted to the Office of Graduate Studies of Texas A...&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 2012 Major Subject: Nuclear Engineering ii An Electrolytic Method to Form Zirconium Hydride Phases...

Kuhr, Samuel Houston

2012-10-19

153

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

SciTech Connect

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.

Totemeier, T.C.

1997-09-01

154

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

PubMed Central

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

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

2013-01-01

155

Pollution of drinking water with nitrate  

Microsoft Academic Search

The main sources of nitrate in man are food and drinking water. The legislature in West Germany intends to lower the permitted level of nitrate in drinking water from the present 90 mg\\/l to 50 mg\\/l in 1982. The European Community has issued a directive that recommends a level of only 25 mg\\/l, and for babies 10 mg\\/l nitrate should

B. Cabel; R. Kozicki; U. Lahl; A. Podbielshi; B. Stachel; S. Struss

1982-01-01

156

Mammalian Nitrate Biosynthesis: Incorporation of 15NH3 into Nitrate is Enhanced by Endotoxin Treatment  

NASA Astrophysics Data System (ADS)

Incorporation of an oral dose of [15N]ammonium acetate into urinary [15N]nitrate has been demonstrated in the rat. Investigation of the regulation of nitrate synthesis has shown that Escherichia coli lipopolysaccharide potently stimulates urinary nitrate excretion (9-fold increase). It was further shown that the enhanced rate of nitrate excretion by lipopolysaccharide was due not to a reduction in nitrate metabolic loss but rather to an increased rate of synthesis. This conclusion was based on finding a proportionally increased incorporation of [15N]ammonium into nitrate nitrogen with lipopolysaccharide treatment. Nitrate biosynthesis was also increased by intraperitoneal injection of carrageenan and subcutaneous injection of turpentine. It is proposed that the pathway of nitrate biosynthesis may be the result of oxidation of reduced nitrogen compounds by oxygen radicals generated by an activated reticuloendothelial system.

Wagner, David A.; Young, Vernon R.; Tannenbaum, Steven R.

1983-07-01

157

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

E-print Network

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

A. Nystrom; M. Thoennessen

2011-02-11

158

Hydrogen pickup measurements in zirconium alloys: Relation to oxidation kinetics  

E-print Network

Hydrogen pickup measurements in zirconium alloys: Relation to oxidation kinetics Adrien Couet a 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

Motta, Arthur T.

159

Stress Corrosion Cracking of Zirconium in Hot Nitric Acid  

Microsoft Academic Search

Zirconium (Zr) has excellent general corrosion resistance in nitric acid. However, stress corrosion cracking (SCC) has been reported in concentrated nitric acid. The purpose of this paper is to evaluate the SCC susceptibility of Zr as a function of HNO[sub 3] concentration, from 6 to 94%, and temperature. The SCC mechanism was also investigated in relation to the electrochemical behavior.

H. Kajimura; H. Nagano

1992-01-01

160

Mn-Ti-Zr (Manganese-Titanium-Zirconium)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume C3 'Non-Ferrous Metal Systems. Part 3: Selected Soldering and Brazing Systems' of Volume 11 'Ternary Alloy Systems - Phase Diagrams, Crystallographic and Thermodynamic Data critically evaluated by MSITź' of Landolt-Börnstein - Group IV 'Physical Chemistry'. It provides data of the ternary system Manganese-Titanium-Zirconium.

Materials Science International Team MSIT

161

Cu-Ti-Zr (Copper-Titanium-Zirconium)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume C3 'Non-Ferrous Metal Systems. Part 3: Selected Soldering and Brazing Systems' of Volume 11 'Ternary Alloy Systems - Phase Diagrams, Crystallographic and Thermodynamic Data critically evaluated by MSITź' of Landolt-Börnstein - Group IV 'Physical Chemistry'. It provides data of the ternary system Copper-Titanium-Zirconium.

Materials Science International Team MSIT

162

Uniform and “Nodule” Corrosion of Zirconium Alloys under Service Conditions  

Microsoft Academic Search

Results concerning uniform and nodule (local) corrosion obtained in SF NIKIÉT are reviewed. The applicability of the electrotechnical theory of high-temperature oxidation of metals to zirconium alloys is analyzed. The conditions of occurrence of nodule corrosion are determined, and the results of a study of process channels and fuel assemblies of RBMK reactors after service at nuclear power plants (NPP)

V. I. Perekhozhev; L. P. Sinel'nikov; A. N. Timokhin; S. A. Averin; M. V. Chernetsov; V. P. Kuznetsov

2003-01-01

163

Preparation and characterization of nanosized zirconium (hydrous) oxide particles  

E-print Network

zirconium salts. Crystal structure, particle size distribution, electrokinetic properties, stability with ultrasound to study their effect on the crystal structure of the calcined samples. I. INTRODUCTION Colloidal vertically into the system placed in a cylindrical cooled container. During the sonication cycle ultrasound

Gleixner, Stacy

164

The corrosion of zirconium under deep geologic repository conditions  

NASA Astrophysics Data System (ADS)

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.

Shoesmith, David W.; Zagidulin, Dmitrij

2011-11-01

165

Polymerization of vinyl aromatic monomers using cyclopentadienyl zirconium catalysts  

SciTech Connect

A process is described for the preparation of polymers of vinyl aromatic monomers having a high degree of syndiotacticity comprising contacting one or more vinyl aromatic monomers under polymerization conditions with a catalyst comprising the reaction product of polymethylaluminoxane and a cyclopentadienyl zirconium (IV) complex.

Schmidt, G.F.; Cambell, R.E. Jr.

1989-02-28

166

Solid State Phase Transformations in Uranium-Zirconium Alloys  

E-print Network

, a basic study on the U-Zr metallurgy was completed using EPMA, DSC, XRD, Optical microscopy, and TEM with a focus on solid state phase transformations in alloys containing 2, 5, 10, 20, 30, and 50wt% zirconium. Alloys were cast by crucible melting...

Irukuvarghula, Sandeep

2013-08-06

167

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

E-print Network

include abrasives, chemicals, metal alloys, sandblasting media, and welding rod coatings. The leading,520 1,600 2,260 3,460 Consumption, zirconium ores and concentrates, apparent (ZrO2 content) W W W W W, dollars per kilogram4 137 195 223 235 187 Net import reliance5 as a percentage of apparent consumption

168

CORROSION OF ZIRCONIUM IN CUPRIC AND FERRIC CHLORIDES  

Microsoft Academic Search

The effect of metallurgical and surface treatments on the corrosion ; behavior of arc-melted reactor-grade zirconium in cupric or ferric chloride ; solutions was investigated. An apparatus was constructed and specimens of ; various metallurgical conditions and surface treatments were tested for 6 days at ; 35 deg C, with aeration. Some correlations were observed between corrosion rate ; and

D. J. Stoops; M. D. Carver; H. Kato

1961-01-01

169

N-U-Zr (Nitrogen-Uranium-Zirconium)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume C4 'Non-Ferrous Metal Systems. Part 4: Selected Nuclear Materials and Engineering Systems' of Volume 11 'Ternary Alloy Systems - Phase Diagrams, Crystallographic and Thermodynamic Data critically evaluated by MSITź' of Landolt-Börnstein - Group IV 'Physical Chemistry'. It provides data of the ternary system Nitrogen-Uranium-Zirconium.

Materials Science International Team MSIT

170

O-U-Zr (Oxygen-Uranium-Zirconium)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume C4 'Non-Ferrous Metal Systems. Part 4: Selected Nuclear Materials and Engineering Systems' of Volume 11 'Ternary Alloy Systems - Phase Diagrams, Crystallographic and Thermodynamic Data critically evaluated by MSITź' of Landolt-Börnstein - Group IV 'Physical Chemistry'. It provides data of the ternary system Oxygen-Uranium-Zirconium.

Materials Science International Team MSIT

171

Synthesis and characterization of mesoporous zirconium oxide thin films  

NASA Astrophysics Data System (ADS)

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.

Mikó, A.; Demirel, A. L.; Somer, M.

2010-06-01

172

Trend Analyses of Nitrate in Danish Groundwater  

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

173

Free amino acids, nitrate, and nitrate reductase in nitrogen fixation by soybean nodules  

E-print Network

FREE AMINO ACIDS, NITRATE, AND NITRATE REDUCTASE IN NITROGEN FIXATION BY SOYBEAN NODULES A Thesis by PAUL CLAYTON MADTES, JR. Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE December 1978 Major Subject: Biophysics FREE AMINO ACIDS, NITRATE, AND NITRATE REDUCTASE IN NITROGEN FIXATION BY SOYBEAN NPDULES A Thesis by PAUL CLAYTON MADTES, JR. Approved as to style and content by: g jap (Chairman...

Madtes, Paul Clayton

2012-06-07

174

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

ERIC Educational Resources Information Center

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)

Bretherick, Leslie

1989-01-01

175

Nitrate, nitrite, and volatile nitrosamines in pickled fish prepared with addition of nitrate  

Microsoft Academic Search

Zusammenfassung Marinierter Hering, hergestellt mit Nitrat als Zusatzstoff, wurde auf Gehalt von Nitrat, Nitrit und flüchtige Nitrosamine untersucht. Der Gehalt von Nitrat war entweder ungefähr 10 mg\\/kg oder variierte von 35 bis 565 mg\\/kg. Der Gehalt von Nitrit war nicht meßbar oder niedrig (2 mg\\/kg). Mehrere Proben enthielten N-Nitrosodimethylamin bis 2.2 ”g\\/ kg.

Erling Pedersen; Inge Meyland

1981-01-01

176

46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.  

Code of Federal Regulations, 2012 CFR

...70 percent of ammonium nitrate and a maximum of 0.4 percent combustible material; (2) Ammonium nitrate with calcium carbonate and/or dolomite, containing more than 80 percent but less than 90 percent of ammonium nitrate and a maximum...

2012-10-01

177

46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.  

Code of Federal Regulations, 2013 CFR

...70 percent of ammonium nitrate and a maximum of 0.4 percent combustible material; (2) Ammonium nitrate with calcium carbonate and/or dolomite, containing more than 80 percent but less than 90 percent of ammonium nitrate and a maximum...

2013-10-01

178

46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.  

Code of Federal Regulations, 2011 CFR

...70 percent of ammonium nitrate and a maximum of 0.4 percent combustible material; (2) Ammonium nitrate with calcium carbonate and/or dolomite, containing more than 80 percent but less than 90 percent of ammonium nitrate and a maximum...

2011-10-01

179

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

PubMed

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 2.35Ć 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

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

2014-04-01

180

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

PubMed

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

Thadani, Udho

2014-08-01

181

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 żDetermination of Nitrate-Nitrite by Automated Colorimetry,ż employs cadmium as the reductant for the conversion of nitrate to nitrite. The nitrite is then analyzed colorimetrically by way ...

182

Nitrite and Nitrate in Cancer  

Microsoft Academic Search

\\u000a \\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a Studies in animal models established the feasibility of sodium nitrite contributing to gastric carcinogenesis primarily via\\u000a conversion to nitrosamines.\\u000a \\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a Most animal studies did not corroborate this assumption.\\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a Exposure of humans to nitrates is primarily from vegetables.\\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a Since a fraction of nitrate is reduced to nitrite by oral bacteria, the largest source of nitrite exposure is also

David M. Klurfeld

183

Removal of Zirconium in Electrometallurgical Treatment of Experimental Breeder Reactor II Spent Fuel  

SciTech Connect

During electrorefining of irradiated, binary U-Zr Experimental Breeder Reactor II fuel, a portion of zirconium is found to dissolve along with uranium. It accumulates in the cadmium pool both as dissolved zirconium and as a zirconium-cadmium intermetallic precipitate. Two electrochemical methods of removing zirconium from the electrorefiner have been evaluated. The first is a three-step method consisting of chemical oxidation of zirconium by CdCl{sub 2} addition, depletion of zirconium from the cadmium pool by electrotransport, and drawdown of zirconium from the LiCl-KCl eutectic salt by using a different electrorefiner configuration. A transport model is employed to determine the cell operating conditions for growing pure zirconium deposits and the throughput rate. The second method eliminates the chemical oxidation step and permits codeposition of uranium and zirconium onto the solid cathode. The transport model is used to assess the level of uranium impurity in the cathode product; an additional step is proposed to reoxidize uranium in the deposit. The two methods are compared from the standpoints of throughput, deposit composition, deposit adherence to a solid cathode mandrel, and the underlying uncertainties. A brief review is given of the related past laboratory work on removal of zirconium from the electrorefiner.

Ahluwalia, Rajesh K.; Hua, Thanh Q.; Geyer, Howard K. [Argonne National Laboratory (United States)

2001-01-15

184

Occurrence of foliar nitrate reductase activity not induced by nitrate in symbiotic nitrogen-fed black alder (Alnus glutinosa)  

E-print Network

Occurrence of foliar nitrate reductase activity not induced by nitrate in symbiotic nitrogen-axenic conditions and supplied with nitrate or nitrate-free nutrient solution. The objectives were to: 1) evaluate the effect of nitrogen source and plant age on leaf nitrate reductase (NR) activity measured in vivo; 2

Paris-Sud XI, Université de

185

Nitrate reduction functional genes and nitrate reduction potentials persist in deeper estuarine sediments. Why?  

PubMed

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

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

2014-01-01

186

Nitrate Uptake, Nitrate Reductase Distribution and their Relation to Proton Release in Five Nodulated Grain Legumes  

PubMed Central

Nitrate uptake, nitrate reductase activity (NRA) and net proton release were compared in five grain legumes grown at 0·2 and 2 mm nitrate in nutrient solution. Nitrate treatments, imposed on 22?d?old, fully nodulated plants, lasted for 21 d. Increasing nitrate supply did not significantly influence the growth of any of the species during the treatment, but yellow lupin (Lupinus luteus) had a higher growth rate than the other species examined. At 0·2 mm nitrate supply, nitrate uptake rates ranged from 0·6 to 1·5 mg N g–1 d–1 in the order: yellow lupin > field pea (Pisum sativum) > chickpea (Cicer arietinum) > narrow?leafed lupin (L. angustifolius) > white lupin (L. albus). At 2 mm nitrate supply, nitrate uptake ranged from 1·7 to 8·2 mg N g–1 d–1 in the order: field pea > chickpea > white lupin > yellow lupin > narrow?leafed lupin. Nitrate reductase activity increased with increased nitrate supply, with the majority of NRA being present in shoots. Field pea and chickpea had much higher shoot NRA than the three lupin species. When 0·2 mm nitrate was supplied, narrow?leafed lupin released the most H+ per unit root biomass per day, followed by yellow lupin, white lupin, field pea and chickpea. At 2 mm nitrate, narrow?leafed lupin and yellow lupin showed net proton release, whereas the other species, especially field pea, showed net OH– release. Irrespective of legume species and nitrate supply, proton release was negatively correlated with nitrate uptake and NRA in shoots, but not with NRA in roots. PMID:12234143

FAN, X. H.; TANG, C.; RENGEL, Z.

2002-01-01

187

Nitrate Monitoring Biosensor System for Aquatic Environment  

Microsoft Academic Search

A microbial biosensor system was developed for nitrate monitoring. The system was constructed with an immobilized microorganism (Paracoccus dinitrificans IAM 12479), a Clark-type oxygen electrode, a micro-tube pump, and a recorder. The method was based on the determination of the oxygen consumption by the microorganism with the electrode in presence of nitrate. Optimum conditions for the sensor system was established

Hideaki Endo; Yasushi Nakazawa; Yoshiyuki Nagano; Huifeng Ren; Tetsuhito Hayashi

188

PARAMAGNETIC RESONANCE OF TERBIUM IN NITRATE  

Microsoft Academic Search

The paramagnetic resonance spectrum of Tb\\/sup 3+\\/ ion was observed in ; lanthanum nitrate monocrystal containing 0.1% terbium nitrate. The spectrum ; consisted of a single electron transition spallated into four lines corresponding ; to TbÂč⁔âč nuclear spin 3\\/4. Measurements were made at 13 K and 8970 and ; 9870 mc. (R.V.J.);

T. I. Sanadze; M. Kolach; G. A. Tsintsadze

1957-01-01

189

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...

190

Nitric oxide, oxidants, and protein tyrosine nitration  

Microsoft Academic Search

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

Rafael Radi

2004-01-01

191

Nitrates and Prussic Acid in Forages  

E-print Network

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...

Provin, Tony; Pitt, John L.

2003-01-06

192

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

SciTech Connect

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.

Kwon, Y.U.

1991-01-28

193

SAMPLING AND ANALYTICAL METHODOLOGY FOR ATMOSPHERIC PARTICULATE NITRATES  

EPA Science Inventory

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

194

Transactions of the ASABE UNCERTAINTIES IN ASSESSING ANNUAL NITRATE  

E-print Network

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

Paris-Sud XI, Université de

195

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

Code of Federal Regulations, 2012 CFR

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

2012-07-01

196

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

197

78 FR 32690 - Certain Ammonium Nitrate From Ukraine  

Federal Register 2010, 2011, 2012, 2013

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

2013-05-31

198

46 CFR 148.227 - Calcium nitrate fertilizers.  

Code of Federal Regulations, 2011 CFR

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

2011-10-01

199

46 CFR 148.227 - Calcium nitrate fertilizers.  

Code of Federal Regulations, 2012 CFR

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

2012-10-01

200

46 CFR 148.227 - Calcium nitrate fertilizers.  

Code of Federal Regulations, 2013 CFR

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

2013-10-01

201

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

202

Dissimilatory nitrate reduction in Clostridium tertium.  

PubMed

Fermentation balance studies were carried out on Clostridium tertium grown with and without nitrate in the medium. Nitrate reduction increased the efficiency of energy produced from glucose by permitting the utilization of additional sites of substrate level phosphorylation. The effect was even more dramatic in C. tertium than in C. perfringens, with increased cell yields of about 30% being observed in the former compared with 20% in the latter. Unlike C. perfringens, C. tertium responded to the presence of nitrate in the medium with an increased growth rate. A slight increase in the Y ATP of these cultures was also observed, and quantitatively, this appeared to be consistent with the prediction of Stouthammer and Bettenhaussen that Y ATP will vary with the growth rate. Thus, C. tertium, like C. perfringens, was able to use nitrate as an electron acceptor in conjunction with its energy metabolism, suggesting that this may be widespread among the nitrate-reducing anaerobes. PMID:203129

Hasan, M; Hall, J B

1977-01-01

203

Nitrate removal from drinking water -- Review  

SciTech Connect

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

Kapoor, A.; Viraraghavan, T. [Univ. of Regina, Saskatchewan (Canada)

1997-04-01

204

Investigation of methods for producing reactor-grade zirconium oxide from a zirconium-bearing chloride-sulfate strip liquor solution. Report of investigations/1984  

SciTech Connect

The Bureau of Mines investigated two alternative methods for treating a zirconium-bearing chloride-sulfate strip liquor to obtain reactor-grade ZrO2. One method involves neutralization with NH3 and the other hydrothermal precipitation. The strip liquor was derived from zircon sand by a Bureau of Mines method for separating zirconium and hafnium via solvent extraction with a tertiary amine. Neutralization with NH3 to precipitate hydrous zirconium oxide required 0.9 to 1.1 g NH3 per gram of zirconium. The NH3 can be recovered for recycle. ZrO2 that met reactor-grade specifications was produced by precipitation with NH3. Hydrothermal precipitation of ZrO2 from strip liquor required that the solution be maintained at 260C and 680 psi for 10 min and in a noncorrodible pressure vessel. In bench-scale experiments both methods gave zirconium recoveries greater than 99 pct.

MacDonald, D.J.; Defilippi, C.E.; Henry, H.G.

1984-02-01

205

Pseudo-constitutivity of nitrate-responsive genes in nitrate reductase mutants  

PubMed Central

In fungi, transcriptional activation of genes involved in NO3- assimilation requires the presence of an inducer (nitrate or nitrite) and low intracellular concentrations of the pathway products ammonium or glutamine. In Aspergillus nidulans, the two transcription factors NirA and AreA act synergistically to mediate nitrate/nitrite induction and nitrogen metabolite derepression, respectively. In all studied fungi and in plants, mutants lacking nitrate reductase (NR) activity express nitrate-metabolizing enzymes constitutively without the addition of inducer molecules. Based on their work in A. nidulans, Cove and Pateman proposed an “autoregulation control” model for the synthesis of nitrate metabolizing enzymes in which the functional nitrate reductase molecule would act as co-repressor in the absence and as co-inducer in the presence of nitrate. However, NR mutants could simply show “pseudo-constitutivity” due to induction by nitrate which accumulates over time in NR-deficient strains. Here we examined this possibility using strains which lack flavohemoglobins (fhbs), and are thus unable to generate nitrate internally, in combination with nitrate transporter mutations (nrtA, nrtB) and a GFP-labeled NirA protein. Using different combinations of genotypes we demonstrate that nitrate transporters are functional also in NR null mutants and show that the constitutive phenotype of NR mutants is not due to nitrate accumulation from intracellular sources but depends on the activity of nitrate transporters. However, these transporters are not required for nitrate signaling because addition of external nitrate (10 mM) leads to standard induction of nitrate assimilatory genes in the nitrate transporter double mutants. We finally show that NR does not regulate NirA localization and activity, and thus the autoregulation model, in which NR would act as a co-repressor of NirA in the absence of nitrate, is unlikely to be correct. Results from this study instead suggest that transporter-mediated NO3- accumulation in NR deficient mutants, originating from traces of nitrate in the media, is responsible for the constitutive expression of NirA-regulated genes, and the associated phenotype is thus termed “pseudo-constitutive”. PMID:23454548

Schinko, Thorsten; Gallmetzer, Andreas; Amillis, Sotiris; Strauss, Joseph

2013-01-01

206

Nuclear-grade zirconium prepared by combining combustion synthesis with molten-salt electrorefining technique  

NASA Astrophysics Data System (ADS)

Zirconium has a low absorption cross-section for neutrons, which makes it an ideal material for use in nuclear reactor applications. However, hafnium typically contained in zirconium causes it to be far less useful for nuclear reactor materials because of its high neutron-absorbing properties. In the present study, a novel effective method has been developed for the production of hafnium-free zirconium. The process includes two main stages: magnesio-thermic reduction of ZrSiO 4 under a combustion mode, to produce zirconium silicide (ZrSi), and recovery of hafnium-free zirconium by molten-salt electrorefining. It was found that, depending on the electrorefining procedure, it is possible to produce zirconium powder with a low hafnium content: 70 ppm, determined by ICP-AES analysis.

Li, Hui; Nersisyan, Hayk H.; Park, Kyung-Tae; Park, Sung-Bin; Kim, Jeong-Guk; Lee, Jeong-Min; Lee, Jong-Hyeon

2011-06-01

207

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

SciTech Connect

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

Cho, D.H.; Armstrong, D.R.; Gunther, W.H. [Argonne National Lab., IL (United States); Basu, S. [Nuclear Regulatory Commission, Washington, DC (United States)

1997-08-01

208

Solubility of zirconium in liquid magnesium and the ML5 alloy  

Microsoft Academic Search

1.It was found that zinc, copper, misch metal, and calcium do not affect the solubility of zirconium in magnesium but promote refining of the structure of the Mg-Zr alloy, while nickel, manganese, silicon, tin, aluminum, beryllium, and iron lower the solubility of zirconium and promote coarsening of the structure.A lower solubility of zirconium in magnesium is promoted by elements which

V. M. Babkin

1968-01-01

209

Complexation Chemistry of Zirconium(IV), Uranium(VI), and Iron(III) with Acetohydroxamic Acid  

Microsoft Academic Search

The complexation of zirconium(IV), uranium(VI), and iron(III) with acetohydroxamic acid (AHA) has been analyzed spectrophotometrically in various ionic strengths at 25°C. Arsenazo III (AAIII) was used as an indicator for unbound zirconium. The SQUAD computational program was employed to evaluate the stability constants. Conditional stability constants of four zirconium complexes Zr(AAIII), , Zr(AHA), and were determined in 1 mol · L HClO4 as

Brent S. Matteson; Peter Tkac; Alena Paulenova

2010-01-01

210

Alternative Processing of High Temperature Hafnium and Zirconium Based Materials  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

211

Effects of solutes on damage production and recovery in zirconium  

SciTech Connect

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.

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

1986-04-01

212

NITRATE REDUCTION AND ASSIMILATION IN CHLORELLA  

PubMed Central

1. Nitrate reduction and assimilation have been studied in Chlorella pyrenoidosa under growth conditions by observing effects on the CO2/O2 gas exchange quotient. 2. During assimilation of glucose in the dark, nitrate reduction is noted as an increase in the R.Q. to about 1.6 caused by an increased rate of carbon dioxide production. 3. During photosynthesis at low light intensity nitrate reduction is evidenced by a reduction in the CO2O2 quotient to about 0.7 caused by a decreased rate of carbon dioxide uptake. 4. Chlorella will assimilate nitrogen from either nitrate or ammonia. When both sources are supplied, only ammonia is utilized and no nitrate reduction occurs. It is inferred that under the usual conditions of growth nitrate is reduced only at a rate required for subsequent cellular syntheses. The effect of nitrate reduction on the CO2O2 quotient therefore provides a measure of the relative rate of nitrogen assimilation. 5. Over-all photosynthetic metabolism may be described from elementary analysis of the cells since excretory products are negligible. The gas exchange predicted in this way is in good agreement with the observed CO2/O2 quotients. PMID:18885680

Cramer, Marian; Myers, Jack

1948-01-01

213

Solvent extraction separation of zirconium (IV) with amberlite LA-1 from citrate solutions  

SciTech Connect

Zirconium was extracted as its anionic complex with various mineral acids by liquid anion exchanger. The chlorocomplex of zirconium was extracted from 6-10 M hydrochloric acid with trioctylamine, triisooctylamine or Aliquat 3365. The sulphotocomplex of zirconium was extracted with Aliquat 3365, Primine JMT, Alamine 336. The nitratocomplex was less extensively utilised for the extractive separation of zirconium. Zirconium was extracted quantitatively from oxalate and malonate media. These extractions were carried out at low pH and separated zirconium from large number of associated elements. The ion exchange chromatographic behaviour of zirconium on column with cation exchange or with anion exchange resin with citric acid as eluent were utilised but extraction studies from citrate solutions were never attempted. From the critical study of existing methods it was observed that zirconium was extracted at narrow pH range; with high concentration of complexing ligand for extraction with liquid anion exchangers and long period of equilibration for extraction as well as stripping. So also such extractions were possible mostly at milligram concentrations involving use of hazardous diluents like benzene. Therefore this paper presented systematic investigations on the solvent extraction separation of zirconium from citrate media with liquid anion exchangers.

Vibhute, C.P.; Khopkar, S.M.

1983-09-01

214

Oxidation characteristics of molybdenum-zirconium oxide cermets  

NASA Technical Reports Server (NTRS)

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

Heitzinger, B.

1984-01-01

215

Microbial Uranium Immobilization Independent of Nitrate Reduction  

SciTech Connect

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.

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

216

Polyimide nanocomposites based on cubic zirconium tungstate  

NASA Astrophysics Data System (ADS)

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

Ramasubramanian Sharma, Gayathri

217

Quantitative EELS analysis of zirconium alloy metal/oxide interfaces.  

PubMed

Zirconium alloys have been long used for fuel cladding and other structural components in water-cooled nuclear reactors, but waterside corrosion is a primary limitation on both high fuel burn-up and extended fuel cycle operation. Understanding the processes that occur at the metal/oxide interface is crucial for a full mechanistic description of the oxidation process. In this paper we show that reliable quantification of the oxygen content at the metal/oxide interface can be obtained by Electron Energy Loss Spectrometry (EELS) if enough care is taken over both the preparation of Transmission Electron Microscopy (TEM) samples and the methodology for quantification of the EELS data. We have reviewed the accuracy of theoretically calculated inelastic partial scattering cross-sections and effective inelastic mean-free-paths for oxygen and zirconium in oxidized Zr-alloy samples. After careful recalibration against a ZrO? powder standard, systematic differences in the local oxygen profile across the interface in different zirconium alloys were found. The presence of a sub-stoichiometric oxide layer (a suboxide) was detected under conditions of slow oxide growth but not where growth was more rapid. This difference could arise from the different corrosion resistances of the alloys or, more likely, as a result of the transition in oxidation behaviour, which refers to a sharp increase in the oxidation rate when the oxide is a few microns thick. PMID:21185456

Ni, Na; Lozano-Perez, Sergio; Sykes, John; Grovenor, Chris

2011-01-01

218

Photodegradation of Paracetamol in Nitrate Solution  

NASA Astrophysics Data System (ADS)

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

Meng, Cui; Qu, Ruijuan; Liang, Jinyan; Yang, Xi

2010-11-01

219

Photodegradation of Paracetamol in Nitrate Solution  

SciTech Connect

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

Meng Cui; Qu Ruijuan; Liang Jinyan; Yang Xi [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China)

2010-11-24

220

Nitrate(mg/L) Celldensity(10  

E-print Network

0 5 10 15 20 25 30 35 40 45 50 0 5 10 23 29 34 47 53 58 71 77 82 95 101 104 Time (h) Nitrate(mg/L) 0 5 10 15 20 25 30 35 40 45 Celldensity(10 5 cells/ml -1 ) 0 10 20 30 40 0 10 20 30 40 50 Nitrate 50 60 0 10 20 30 40 50 Nitrate(mg/L -1 ) 0 5 10 15 20 25 0 10 20 30 40 50 CellDensity(x105 cells/ml-1

Hall, Sharon J.

221

Nitrates and detinning in canned carrots  

E-print Network

in nitrate content was reported not only for dif- ferent vegetables, but between samples of the same vege- table. The maximum nitrate content reported in 1967 was 2, 957 ppm in a celery sample. The minimum was 11 ppm in a sample of canned tomatoes with a... carrot sample next with 18 ppm on a fresh weight basis. The range of nitrate levels was highest for carrots at 18 to 194 ppm for a ten fold difference. The minimum range for a vegetable was in celery with 2, 614 to 2, 957 ppm for only a 0. 1 fold dif...

Florine, Thomas Edward

2012-06-07

222

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

PubMed Central

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

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

1978-01-01

223

Phase diagram of ammonium nitrate  

SciTech Connect

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

Dunuwille, Mihindra; Yoo, Choong-Shik, E-mail: csyoo@wsu.edu [Department of Chemistry and Institute for Shock Physics, Washington State University, Pullman, Washington 99164 (United States)] [Department of Chemistry and Institute for Shock Physics, Washington State University, Pullman, Washington 99164 (United States)

2013-12-07

224

The capacity for nitrate regulation of root hydraulic properties correlates with species’ nitrate uptake rates  

Microsoft Academic Search

A mechanism whereby water flow towards root surfaces is stimulated when exposed to nutrient patches may be evolutionarily\\u000a desirable in environments with heterogeneous soils. Indeed, the presence of nitrate has been shown to increase root hydraulic\\u000a conductance in a few agricultural species characterized by high nitrate demand. Does a similar stimulation of root conductivity\\u000a in response to external nitrate addition

Anna Górska; Jillian W. Lazor; Anna K. Zwieniecka; Christopher Benway; Maciej A. Zwieniecki

2010-01-01

225

Qualitative Determination of Nitrate with Triphenylbenzylphosphonium Chloride.  

ERIC Educational Resources Information Center

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

Berry, Donna A.; Cole, Jerry J.

1984-01-01

226

THE NITRATION OF POWDERED URANIUM BY NITROGEN  

Microsoft Academic Search

The nitration of powdered uranium by nitrogen was studied by- ; thermograviimetry- between 300 and 700 deg C. The results obtained show the ; complexity of a powdered soidgas reaction and chiefly the effect of granulometry. ; (trauth);

C. Moreau; J. Philippot

1961-01-01

227

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

228

Nitrate assimilation in the forage legume Lotus japonicus L  

Microsoft Academic Search

Nitrate assimilation in the model legume, Lotus japonicus, has been investigated using a variety of approaches. A gene encoding a nitrate-inducible nitrate reductase (NR) has been cloned and appears to be the only NR gene present in the genome. Most of the nitrate reductase activity (NRA) is found in the roots and the plant assimilates the bulk of its nitrogen

Ian M. Prosser; Agnes Massonneau; Audra J. Smyth; Rosi N. Waterhouse; Brian G. Forde; David T. Clarkson

2006-01-01

229

Original Articles Cytometric Quantification of Nitrate Reductase by  

E-print Network

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

Jochem, Frank J.

230

The distribution of nitrate 15 N in marine sediments  

E-print Network

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

Sigman, Daniel M.

231

CHL1 Functions as a Nitrate Sensor in Plants  

E-print Network

CHL1 Functions as a Nitrate Sensor in Plants Cheng-Hsun HO,',2 Shan-Hua Lin,2Heng-Cheng HU,2 and Yi concentrations. Previous studies showed that T1 01-phosphorylated CHL1 is a high-affinity nitrate transporter- and sensing-decoupled mutant showed that the nitrate transporter CHL1 functions as a nitrate sensor. Primary

232

Supported bimetallic palladium catalysts for water-phase nitrate reduction  

Microsoft Academic Search

Technologies for the removal of nitrate from drinking water and waste water will be required in the near future, and the catalytic nitrate reduction is one of the most promising methods. So far, the understanding of nitrate reducing catalysts has been very poor. Experimental trends in nitrate removal activity and selectivity for various pH values, and for different bimetallic catalysts,

Ulf Prüsse; Klaus-Dieter Vorlop

2001-01-01

233

Tyrosine nitration in prostaglandin H(2) synthase  

Microsoft Academic Search

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

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

2002-01-01

234

Protein Nitration in Placenta - Functional Significance  

PubMed Central

Crucial roles of the placenta are disrupted in early and mid-trimester pregnancy loss, preeclampsia, eclampsia and intrauterine growth restriction. The pathophysiology of these disorders includes a relative hypoxia of the placenta, ischemia/reperfusion injury, an inflammatory response and oxidative stress. Reactive oxygen species including nitric oxide (NO), carbon monoxide and superoxide have been shown to participate in trophoblast invasion, regulation of placental vascular reactivity and other events. Superoxide, which regulates expression of redox sensitive genes, has been implicated in up-regulation of transcription factors, antioxidant production, angiogenesis, proliferation and matrix remodeling. When superoxide and nitric oxide are present in abundance, their interaction yields peroxynitrite a potent pro-oxidant, but also alters levels of nitric oxide, which in turn affect physiological functions. The peroxynitrite anion is extremely unstable thus evidence of its formation in vivo has been indirect via the occurrence of nitrated moieties including nitrated lipids and nitrotyrosine residues in proteins. Formation of 3-nitrotyrosine (protein nitration) is a “molecular fingerprint” of peroxynitrite formation. Protein nitration has been widely reported in a number of pathological states associated with inflammation but is reported to occur in normal physiology and is thought of as a prevalent, functionally relevant post-translational modification of proteins. Nitration of proteins can give either no effect, a gain or a loss of function. Nitration of a range of placental proteins is found in normal pregnancy but increased in pathologic pregnancies. Evidence is presented for nitration of placental signal transduction enzymes and transporters. The targets and extent of nitration of enzymes, receptors, transporters and structural proteins may markedly influence placental cellular function in both physiologic and pathologic settings. PMID:18851882

Webster, RP; Roberts, VHJ; Myatt, L

2009-01-01

235

Low-level nitrate waste process development  

SciTech Connect

Chemical methods of denitrification of simulated low-level nitrate wastes were investigated on a laboratory scale. Various reducing agents and catalysts were tested in evaporation and drying experiments to determine denitrification efficiency, NO/sub x/ off-gas generation, and future process applicability. A peer review was conducted to gain input on processing needs and preferences from actual nitrate waste generators. Experimental results are discussed and conclusions presented. 10 tables.

Meile, L.J.; Johnson, A.J.

1984-01-01

236

Nitrate pollution of groundwater in northern China  

Microsoft Academic Search

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

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

1996-01-01

237

Nitrate in aquifers beneath agricultural systems  

Microsoft Academic Search

Abstract Research from several regions of the world provides spatially anecdotal evidence to hypothesize which hydrologic and agricultural factors contribute to groundwater,vulnerability to nitrate contamination. Analysis of nationally consistent measurements,from the U.S. Geological Survey’s NAWQA program confirms these hypotheses for a substantial range of agricultural systems. Shallow unconfined aquifers are most susceptible to nitrate contamination associated with agricultural systems. Alluvial

M. R. Burkart; J. D. Stoner

2007-01-01

238

Stimulating nitrate removal processes of restored wetlands.  

PubMed

The environmental and health effects caused by nitrate contamination of aquatic systems are a serious problem throughout the world. A strategy proposed to address nitrate pollution is the restoration of wetlands. However, although natural wetlands often remove nitrate via high rates of denitrification, wetlands restored for water quality functions often fall below expectations. This may be in part because key drivers for denitrification, in particular soil carbon, are slow to develop in restored wetlands. We added organic soil amendments that range along a gradient of carbon lability to four newly restored wetlands in western New York to investigate the effect of carbon additions on denitrification and other processes of the nitrogen cycle. Soil carbon increased by 12.67-63.30% with the use of soil amendments (p ? 0.0001). Soil nitrate, the carbon to nitrogen ratio, and microbial biomass nitrogen were the most significant predictors of denitrification potential. Denitrification potential, potential net nitrogen nitrification and mineralization, and soil nitrate and ammonium, were highest in topsoil-amended plots, with increases in denitrification potential of 161.27% over control plots. While amendment with topsoil more than doubled several key nitrogen cycling processes, more research is required to determine what type and level of amendment application are most effective for stimulating removal of exogenous nitrate and meeting functional goals within an acceptable time frame. PMID:24915604

Ballantine, Kate A; Groffman, Peter M; Lehmann, Johannes; Schneider, Rebecca L

2014-07-01

239

Process for decomposing nitrates in aqueous solution  

DOEpatents

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

Haas, Paul A. (Knoxville, TN)

1980-01-01

240

Protein tyrosine nitration in the cell cycle  

SciTech Connect

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.

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

241

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

E-print Network

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

Sigman, Daniel M.

242

Differential Effect of Tungsten on the Development of Endogenous and Nitrate-Induced Nitrate Reductase Activities in Soybean Leaves 1  

PubMed Central

The effect of tungsten on the development of endogenous and nitrate-induced NADH- and FMNH2-linked nitrate reductase activities in primary leaves of 10-day-old soybean (Glycine max [L.] Merr.) seedlings was studied. The seedlings were grown with or without exogenous nitrate. High levels of endogenous nitrate reductase activities developed in leaves of seedlings grown without nitrate. However, no endogenous nitrite reductase activity was detected in such seedlings. The FMNH2-linked nitrate reductase activity was about 40% of NADH-linked activity. Tungsten had little or no effect on the development of endogenous NADH- and FMNH2-linked nitrate reductase activities, respectively. By contrast, in nitrate-grown seedlings, tungsten only inhibited the nitrate-induced portion of NADH-linked nitrate reductase activity, whereas the FMNH2-linked activity was inhibited completely. Tungsten had no effect on the development of nitrate-induced nitrite reductase activity. The complete inhibition of FMNH2-linked nitrate reductase activity by tungsten in nitrate-grown plants was apparently an artifact caused by the reduction of nitrite by nitrite reductase in the assay system. The results suggest that in soybean leaves either the endogenous nitrate reductase does not require molybdenum or the molybdenum present in the seed is preferentially utilized by the enzyme complex as compared to nitrate-induced nitrate reductase. PMID:16662475

Aslam, Muhammad

1982-01-01

243

Thermal expansion of nitrates of lead, barium and strontium  

Microsoft Academic Search

The expansion coefficients of barium, strontium and lead nitrates have been studied above room temperatures. Lead nitrate\\u000a decomposes rapidly beyond 200° C. while crystals of barium nitrate crack above 270° C. Strontium nitrate exhibited no such\\u000a phenomena till 550° C.\\u000a \\u000a These crystals are isomorphous. The expansion coefficients of lead and strontium nitrates are nearly equal; they also possess\\u000a the same

R. Srinivasan

1955-01-01

244

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

E-print Network

Zirconium oxidation under high energy heavy ion irradiation N. BĂ©rerd, A. Chevarier, N. Moncoffre This paper concerns the study of zirconium oxidation under irradiation with high energetic Xe ions oxidation data. 1 #12;I. INTRODUCTION This paper deals with the influence of heavy ion irradiation

Paris-Sud XI, Université de

245

Phase-field simulation of hydride precipitation in bi-crystalline zirconium  

E-print Network

the precipitation process, different variants are arranged in such a way that the free energy is minimized. The aPhase-field simulation of hydride precipitation in bi-crystalline zirconium X.Q. Ma a , S.Q. Shi a Abstract The morphological evolution of c-hydride precipitation and growth in a zirconium bi

Chen, Long-Qing

246

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

SciTech Connect

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.

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

247

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

SciTech Connect

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.

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

248

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

NASA Technical Reports Server (NTRS)

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

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

1981-01-01

249

A STUDY OF METAL IGNITIONS. II. THE SPONTANEOUS IGNITION OF ZIRCONIUM  

Microsoft Academic Search

Spontaneous ignition of zirconium sheets, varying in thickness from ; 0.0l0 to 0.250 in., can occur by exposing it rapidly to oxygen under pressure. ; The ignition limits, in terms of oxygen pressure and concentration, necessary to ; produce spontaneous ignition, were determined for zirconium and Zircaloy. ; lgnition resulting from the breaking of 1\\/4 in. bars (in tension) was

F. E. Littman; F. M. Church; E. M. Kinderman

1961-01-01

250

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

E-print Network

, and Latonya Kilpatrick Colgate-PalmoliVe Company, 909 RiVer Road Piscataway, New Jersey 08854, Department no skeleton electrons. The zirconium-aluminum-glycine (ZAG) complex is an efficacious antiperspirant salt of the ZAG salt. Furthermore, knowing the structure of zirconium-amino acid complexes should help chemists

Li, Jing

251

Lithium aluminate/zirconium material useful in the production of tritium  

DOEpatents

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.

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

1984-10-09

252

Preparation of lead-zirconium-titanium film and powder by electrodeposition  

Microsoft Academic Search

A process is disclosed for the preparation of lead-zirconium-titanium (PZT) film and powder compositions. The process comprises the steps of providing an electrodeposition bath, providing soluble salts of lead, zirconium and titanium metals to this bath, electrically energizing the bath to thereby direct ions of each respective metal to a substrate electrode and cause formation of metallic particles as a

R. N. Bhattacharya; D. S. Ginley

1995-01-01

253

Preparation of lead-zirconium-titanium film and powder by electrodeposition  

Microsoft Academic Search

A process for the preparation of lead-zirconium-titanium (PZT) film and powder compositions. The process comprises the steps of providing an electrodeposition bath, providing soluble salts of lead, zirconium and titanium metals to this bath, electrically energizing the bath to thereby direct ions of each respective metal to a substrate electrode and cause formation of metallic particles as a recoverable film

Raghu N. Bhattacharya; David S. Ginley

1995-01-01

254

Manganese porphyrin multilayer films assembled on ITO electrodes via zirconium phosphonate chemistry: chemical and electrochemical  

E-print Network

Manganese porphyrin multilayer films assembled on ITO electrodes via zirconium phosphonate University, 2145 Sheridan Road, Evanston, IL 60208-3113 A supported manganese porphyrin-based oxidation)porphyrinato] manganese(III) chloride (2) and zirconium(IV) ions on indiumïżœtin oxide electrodes. This assembly technique

255

Lithium aluminate/zirconium material useful in the production of tritium  

DOEpatents

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.

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

1984-10-09

256

Nitrate in groundwater in the United States  

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

257

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

E-print Network

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

Youssef, Mostafa Youssef Mahmoud

2014-01-01

258

Fused salt process for purifying zirconium and/or hafnium tetrachlorides  

SciTech Connect

This patent describes a fused salt process for continuously purifying zirconium and/or hafnium tetrachloride dissolved in a molten bath in a vessel. It comprises: maintaining a mass of a suitable mixture of salts, including zirconium and/or hafnium tetrachloride; heating the mixture of salts to a temperature at or immediately below the vaporization temperature of the zirconium and/or hafnium tetrachloride at which temperature the mixture of salts is fused to form a molten, tetrachloride-dissolving bath; continuously introducing into the dissolving bath a zirconium and/or hafnium tetrachloride powder; heating a portion of the dissolving bath in situ to a temperature higher than the vaporization temperature of the zirconium and/or hafnium tetrachloride so as to vaporize the tetrachloride; internally circulating the dissolving bath whereby the portion of the dissolving bath at the high temperature circulate with the bath at the lower temperature.

Lee, E.D.

1991-04-23

259

Potential problems with intermittent nitrate therapy.  

PubMed

The organic nitrates continue to be widely used in clinical practice. The development of tolerance to these agents is now a well-recognized problem, although the use of a nitrate-free interval or compounds with specialized pharmacokinetic profiles can overcome this difficulty. Despite this success, prospective studies of intermittent transdermal nitroglycerin have suggested that the nitrate-free interval may be associated with two potential problems. The first is the development of crescendo angina during the nitrate-free interval. Such unstable clinical events occurring during the nitrate-free interval have been termed 'rebound angina' and are reminiscent of ischemic events reported in the munitions industry, where workers are exposed to high nitroglycerin concentrations. Intermittent nitroglycerin therapy has also been reported to cause a decrease in treadmill walking time to the onset of angina. This has been suggested from observations made in clinical trials of intermittent transdermal nitroglycerin therapy and was recently confirmed in a study from our laboratory, where the withdrawal of transdermal nitroglycerin was associated with a reduction in tread-mill exercise performance for a period of at least 6 h. Although rebound ischemia has been reported, this has not been a consistent observation in all clinical trials of intermittent nitrate therapy. Furthermore, it is not at all clear that a decrease in exercise tolerance, which would usually be occurring in the evening hours, is of any clinical importance. Nevertheless, these are potentially important observations that warrant further study and may provide further insight into the pathophysiology of nitrate tolerance. PMID:8634920

Parker, J D

1996-05-01

260

Nitrate in aquifers beneath agricultural systems.  

PubMed

Research from several regions of the world provides spatially anecdotal evidence to hypothesize which hydrologic and agricultural factors contribute to groundwater vulnerability to nitrate contamination. Analysis of nationally consistent measurements from the U.S. Geological Survey's NAWQA program confirms these hypotheses for a substantial range of agricultural systems. Shallow unconfined aquifers are most susceptible to nitrate contamination associated with agricultural systems. Alluvial and other unconsolidated aquifers are the most vulnerable and also shallow carbonate aquifers that provide a substantial but smaller contamination risk. Where any of these aquifers are overlain by permeable soils the risk of contamination is larger. Irrigated systems can compound this vulnerability by increasing leaching facilitated by additional recharge and additional nutrient applications. The system of corn, soybean, and hogs produced significantly larger concentrations of groundwater nitrate than all other agricultural systems because this system imports the largest amount of N-fertilizer per unit production area. Mean nitrate under dairy, poultry, horticulture, and cattle and grains systems were similar. If trends in the relation between increased fertilizer use and groundwater nitrate in the United States are repeated in other regions of the world, Asia may experience increasing problems because of recent increases in fertilizer use. Groundwater monitoring in Western and Eastern Europe as well as Russia over the next decade may provide data to determine if the trend in increased nitrate contamination can be reversed. If the concentrated livestock trend in the United States is global, it may be accompanied by increasing nitrogen contamination in groundwater. Concentrated livestock provide both point sources in the confinement area and intense non-point sources as fields close to facilities are used for manure disposal. Regions where irrigated cropland is expanding, such as in Asia, may experience the greatest impact of this practice on groundwater nitrate. PMID:17711000

Burkart, M R; Stoner, J D

2007-01-01

261

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

PubMed Central

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

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

1993-01-01

262

Nitrate reductase activity in corn seedlings as affected by light and nitrate content of nutrient media  

Microsoft Academic Search

Young corn plants placed in complete darkness for 48 hours lost 90% of their nitrate reductase activity. The activity was quickly restored when the plants were returned to the light. In other experiments, corn plants were grown under artificial shade in the greenhouse. The nitrate reductase activity in these plants decreased roughly in proportion to the amount of shading. It

R. H. Hageman; D. Flesher

1960-01-01

263

COMPARATIVE KINETIC STUDIES OF NITRATE-LIMITED GROWTH AND NITRATE UPTAKE IN PHYTOPLANKTON IN CONTINUOUS CULTURE  

EPA Science Inventory

A comparative kinetic study of nitrate-limited growth and nitrate uptake was carried out in chemostat cultures of Ankistrodesmus falcatus, Asterionella formosa, Fragilaria crotonensis. In each species growth rate (microgram) was related to total cell nitrogen or cell quota (q) by...

264

Fundamental studies into zirconium modified phosphonic acid based ionic membranes  

NASA Astrophysics Data System (ADS)

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.

Schlichting, Gregory Joseph

265

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

Microsoft Academic Search

On the basis of the normalization to phosphate, a significant amount of nitrate is missing from the deep Bering Sea (BS). Benthic denitrification has been suggested previously to be the dominant cause for the BS nitrate deficit. We measured water column nitrate 15N\\/14N and 18O\\/16O as integrative tracers of microbial denitrification, together with pore water-derived benthic nitrate fluxes in the

Moritz F. Lehmann; Daniel M. Sigman; Daniel C. McCorkle; Brigitte G. Brunelle; Sharon Hoffmann; Markus Kienast; Greg Cane; Jaclyn Clement

2005-01-01

266

Contribution of atmospheric nitrate deposition to nitrate loading in the Chesapeake Bay. Final report  

SciTech Connect

Recent studies have suggested that nitrate introduced into the Chesapeake Bay via atmospheric deposition may be a significant source of excess nutrients. In order to determine if concerns about atmospheric deposition are justified, modeled estimates of wetfall nitrate deposition over the Chesapeake Bay basin, based on monitoring data collected in 1984, were used to estimate basin-wide nitrate loading (1.38 x 10/sup 8/ kg) over the land area of the basin. Estimates of transfer coefficients and nitrate loadings to the Bay for various land-use categories were also calculated, using figures developed by the EPA Chesapeake Bay Program. The conservative nature of assumptions made in developing these figures suggests that the actual percentage contribution of atmospheric nitrate deposition may be lower than the estimated value.

Tyler, M.

1988-12-01

267

Fast-neutron scattering cross sections of elemental zirconium  

SciTech Connect

Differential neturon-elastic-scattering cross sections of elemental zirconium are measured from 1.5 to 4.0 MeV at intervals of less than or equal to 200 keV. Inelastic-neutron-scattering cross sections corresponding to the excitation of levels at observed energies of: 914 +- 25, 1476 +- 37, 1787 +- 23, 2101 +- 26, 2221 +- 17, 2363 +- 14, 2791 +- 15 and 3101 +- 25 keV are determined. The experimental results are interpreted in terms of the optical-statistical model and are compared with corresponding quantities given in ENDF/B-V.

Smith, A.B.; Guenther, P.T.

1982-12-01

268

Bulk Hydrides and Delayed Hydride Cracking in Zirconium Alloys  

NASA Astrophysics Data System (ADS)

Zirconium alloys are susceptible to engineering problems associated with the uptake of hydrogen throughout their design lifetime in nuclear reactors. Understanding of hydrogen embrittlement associated with the precipitation of brittle hydride phases and a sub-critical crack growth mechanism known as Delayed Hydride Cracking (DHC) is required to provide the engineering justifications for safe reactor operation. The nature of bulk zirconium hydrides at low concentrations (< 100 wt. ppm) is subject to several contradictory descriptions in the literature associated with the stability and metastability of gamma-phase zirconium hydride. Due to the differing volume expansions (12-17%) and crystallography between gamma and delta hydride phases, it is suggested that the matrix yield strength may have an effect on the phase stability. The present work indicated that although yield strength can shift the phase stability, other factors such as microstructure and phase distribution can be as or more important. This suggests that small material differences are the reason for the literature discrepancies. DHC is characterised by the repeated precipitation, growth, fracture of brittle hydride phases and subsequent crack arrest in the ductile metal. DHC growth is associated primarily the ability of hydrogen to diffuse under a stress induced chemical potential towards a stress raiser. Knowledge of the factors controlling DHC are paramount in being able to appropriately describe DHC for engineering purposes. Most studies characterise DHC upon cooling to the test temperature. DHC upon heating has not been extensively studied and the mechanism by which it occurs is somewhat controversial in the literature. This work shows that previous thermo-mechanical processing of hydrided zirconium can have a significant effect on the dissolution behaviour of the bulk hydride upon heating. DHC tests with gamma-quenched, furnace cooled-delta and reoriented bulk hydrides upon heating and DHC upon cooling suggest that the amount of hydrogen in solution is the primary factor controlling the occurrence of DHC and consistent with the postulation that the stress induced chemical potential is the driving force for DHC.

Tulk, Eric F.

269

Tracing Nitrate Deposition Using ? 17O  

NASA Astrophysics Data System (ADS)

Assessing the impact of atmospheric deposition of fixed nitrogen on local, regional, and global biogeochemical cycles has received much attention in recent years. Local and regional ecosystems can suffer from eutrophication and shrinking biodiversity from the increased nitrogen flux, in addition to degradation associated with acid rain ( an increasing proportion of which is as HNO3 ). On a global scale, the effect of nitrogen fertilization on CO2 uptake rates is one of the biggest unknowns in global warming research. This renewed interest has led to new attempts to utilize current, and in the development of new, analytical techniques in order to better understand the source, sink and transport mechanisms of atmospheric nitrogen deposition. Its role as the primary sink of the NOx cycle makes atmospheric nitrate (as particulate nitrate or nitric acid ) the primary source of nitrogen deposition. Stable isotopes of nitrogen and oxygen have been used by several researchers to trace atmospheric nitrate through the biogeochemical system. 15N ratios have been problematic due to the lack of large fractionations and an overlap of 15N ratios between sources. Initial studies of 18O ratios showed promise due to the large enrichment (60 ‰ ) in atmospheric nitrate. However, subsequent studies showed an ? 18O spread of 25 - 80 ‰ and have made quantitative analysis of mixing reservoirs difficult. No studies of ? 17O nitrates have been published. For ? 17O, thermodynamic, kinetic, and equilibrium isotope effects dictate that ? 17O = .52 x ? 18O . Certain photochemical processes violate this rule due to quantum effects and are quantified by ? 17O = ? 17O -.52 x ? 18O which are called mass independent fractionations (MIF). Atmospheric nitrates have now been measured and have been found to have a large MIF; ? 17O ~ 25 ‰ and a small range +/- 4‰ . The large variations in ? 18O of atmospheric nitrate are due to mass dependent fractions from transport and source ratios, and do not effect the ? 17O. In addition, post depositional fractionations associated with soil migration and microbial utilization are mass dependent processes. The ? 17O can then be used as a conservative trace of atmospheric nitrate deposition. A variety of soil measurements demonstrate the practicality of using MIF of atmospheric nitrate as a conservative tracer. Antarctic soils have a ? 17O ~ 30 ‰ acknowledging they are purely atmospheric in origin. Chilean desert soils with ? 17O ~ 20 ‰ be 2/3 atmospheric and 1/3 biologically derived. Mojave desert soils ? 17O range from ~ 0 -16 ‰ indicating that some soils are dominated by biologic nitrification and others have in excess of 50 % atmospheric contribution. Stream waters collected in southern California show a ? 17O of 0-5 ‰ indicating atmospheric contributions of 0 to 20 %.

Michalski, G m; Hernandez, L.; Meixner, T.; Fenn, M.; Thiemens, M.

2001-12-01

270

Effect of Ammonium and Nitrate on Ferric Chelate Reductase and Nitrate Reductase in Vaccinium Species  

PubMed Central

• Background and Aims Most Vaccinium species have strict soil requirements for optimal growth, requiring low pH, high iron availability and nitrogen primarily in the ammonium form. These soils are limited and are often located near wetlands. Vaccinium arboreum is a wild species adapted to a wide range of soils, including high pH, low iron, and nitrate?containing soils. This broader soil adaptation in V. arboreum may be related to increased efficiency of iron or nitrate uptake compared with the cultivated Vaccinium species. • Methods Nitrate, ammonium and iron uptake, and nitrate reductase (NR) and ferric chelate reductase (FCR) activities were compared in two Vaccinium species grown hydroponically in either nitrate or ammonia, with or without iron. The species studied were the wild V. arboreum and the cultivated V. corymbosum interspecific hybrid, which exhibits the strict soil requirements of most Vaccinium species. • Key Results Ammonium uptake was significantly greater than nitrate uptake in both species, while nitrate uptake was greater in the wild species, V. arboreum, compared with the cultivated species, V. corymbosum. The increased nitrate uptake in V. arboreum was correlated with increased root NR activity compared with V. corymbosum. The lower nitrate uptake in V. corymbosum was reflected in decreased plant dry weight in this species compared with V. arboreum. Root FCR activity increased significantly in V. corymbosum grown under iron?deficient conditions, compared with the same species grown under iron?sufficient conditions or with V. arboreum grown under either iron condition. • Conclusions. V. arboreum appears to be more efficient in acquiring nitrate compared with V. corymbosum, possibly due to increased NR activity and this may partially explain the wider soil adaptation of V. arboreum. PMID:14980973

POONNACHIT, U.; DARNELL, R.

2004-01-01

271

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

PubMed Central

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

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

2012-01-01

272

Vulnerability of streams to legacy nitrate sources.  

PubMed

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

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

2013-04-16

273

Exclusion of Nitrate from Frozen Aqueous Solutions  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

274

Proteomic Approaches to Analyze Protein Tyrosine Nitration  

PubMed Central

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

Feeney, Maria B.

2013-01-01

275

In Vivo Assay of Nitrate Reductase in Cotton Leaf Discs  

PubMed Central

Factors affecting nitrate reduction by leaf discs of cotton (Gossypium hirsutum L.) were investigated. When incubated in 30 mm nitrate, discs reduced nitrate much more slowly under air or O2 than under N2. Inhibition by O2 did not occur at nitrate levels of 100 mm or greater. Treatment with arsenate had little effect under N2 but stimulated nitrate reduction under air. Similarly, ammonium inhibited nitrate reduction, with the inhibition being partially relieved by arsenate. Uptake of nitrate was unaffected by ammonium. The NAD/NADH ratio increased in response to both oxygen and ammonium. The effects of these treatments on nitrate reduction can be explained by competition with nitrate for NADH generated by glycolysis. PMID:16658325

Radin, J. W.

1973-01-01

276

Analysis of uranium-zirconium-carbon-oxygen quaternary system for applications in advanced zirconium carbide coated TRISO particles  

NASA Astrophysics Data System (ADS)

The implementation of ZrC for use in oxide TRISO particles for Very High Temperature Reactor (VHTR) conditions to prevent kernel overpressurization and kernel migration has been proposed by several researchers. Analysis is performed incorporating first-principles thermodynamics along with out-of-pile experimental work. UO2+x-U4O9 powders are created and used for in-vacuo thermogravimetric testing with both carbon and zirconium carbide powders to evaluate the efficiency of ZrC for usage as an oxygen getter in oxide TRISO fuels.

Degange, Jonathan Lee

277

Ammonium and nitrate tolerance in lichens.  

PubMed

Since lichens lack roots and take up water, solutes and gases over the entire thallus surface, these organisms respond more sensitively to changes in atmospheric purity than vascular plants. After centuries where effects of sulphur dioxide and acidity were in the focus of research on atmospheric chemistry and lichens, recently the globally increased levels of ammonia and nitrate increasingly affect lichen vegetation and gave rise to intense research on the tolerance of lichens to nitrogen pollution. The present paper discusses the main findings on the uptake of ammonia and nitrate in the lichen symbiosis and to the tolerance of lichens to eutrophication. Ammonia and nitrate are both efficiently taken up under ambient conditions. The tolerance to high nitrogen levels depends, among others, on the capability of the photobiont to provide sufficient amounts of carbon skeletons for ammonia assimilation. Lowly productive lichens are apparently predisposed to be sensitive to excess nitrogen. PMID:20096494

Hauck, Markus

2010-05-01

278

Nitrate salt immobilization process development and implementation  

SciTech Connect

The waste nitrate salts generated at the Rocky Flats Plant (RFP) were determined to be unacceptable in their present form for shipment to and storage at the Nevada Test Site, according to the recently implemented Waste Acceptance Criteria. A reduction in the dispersibility and oxidizing potential of the salt was necessary. Various methods of immobilization were investigated to determine the waste form with the highest possible waste loading and the most cost effective processing. Portland cement was selected as the most effective binder (in terms of cost and performance), with a 55 wt % waste loading and a 1.5 water-to-cement ratio. A nitrate salt immobilization process has been installed in the liquid waste processing building. The process uses dry nitrate salts from the existing spray dryer, spray dryer feed solution, and Portland cement. The resulting waste grout is packaged in a plastic lined, corrugated fiberboard tri-wall box, and shipped to the Nevada Test Site for burial.

Petersen, R.D.; Johnson, A.J.; Peter, K.G.

1986-11-20

279

Techniques for Measurement of Nitrate Movement in Soils  

NASA Technical Reports Server (NTRS)

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.

Broadbent, F. E.

1971-01-01

280

Measuring Nitrates and Their Effect on Water Quality  

NSDL National Science Digital Library

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.

Johnson, Larry

281

Radiation induced creep and growth of zirconium alloys  

NASA Astrophysics Data System (ADS)

The strain under irradiation of zirconium and its alloys is calculated within a simple rate theory approach. Network dislocations and interstitial dislocation loops with their Burgers vector oriented parallel to the crystal basal plane are assumed to climb by preferentially attracting interstitials with respect to vacancies, while the grain boundaries act as neutral sinks and absorb therefore more vacancies than interstitials. This same theory has been applied by Fainstein-Pedraza, Savino and Pedraza for modelling the irradiation growth of cold worked zirconium alloys. It is now extended by including the effect of vacancy traps and the stress induced preferential bias for interstitials of those dislocations favourably oriented with respect to an external or internal stress field. In addition, a model which allows to correlate the deformation of the individual grains with the strain of the polycrystalline specimen where they pertain is developed. The stresses induced within the same grain while it deforms inside the textured crystal are also numerically calculated. Those stresses modify the grain strain via the SIPA mechanism and the stresses-strains are then coupled. The calculated crystal deformation is strongly dependent on texture. For tubes with the c axis oriented preferentially on an axial plane, a rapid increase of the longitudinal strain rate is predicted at high doses.

Savino, E. J.; Laciana, C. E.

1980-05-01

282

Retrospective Reactor Dosimetry with Zirconium Alloy Samples in a Pwr  

NASA Astrophysics Data System (ADS)

Retrospective measurements are routinely performed with stainless steel samples. Recent experiments have been successfully conducted using zirconium alloy samples, involving somewhat different neutron activation reactions than are normally encountered with stainless steel samples. The sample alloy compositions consisted of ZIRLO which nominally contains about 1.0% (by weight) niobium, 0.65-1.0% tin, and 0.1% iron, with the balance zirconium. The activation products observed in the samples by gamma spectroscopy included Zr-95, Nb-93m, Nb-95, Sn-113, Sb-125, Mn-54, Co-60, Nb-94, and Ta-182. The niobium was then chemically separated following ASTM procedure El297 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. The results were used to experimentally determine the fast and thermal fluxes in the Vogtle unit 2 PWR.

Greenwood, L. R.; Foster, J. P.

2009-08-01

283

Green strength of zirconium sponge and uranium dioxide powder compacts  

SciTech Connect

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

Balakrishna, Palanki [Nuclear Fuel Complex, Hyderabad 500 062 (India)], E-mail: bpalanki@rediffmail.com; Murty, B. Narasimha; Sahoo, P.K.; Gopalakrishna, T. [Nuclear Fuel Complex, Hyderabad 500 062 (India)

2008-07-15

284

Hydrogen pickup measurements in zirconium alloys: Relation to oxidation kinetics  

NASA Astrophysics Data System (ADS)

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.

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

2014-08-01

285

9-Amino­acridinium nitrate monohydrate  

PubMed Central

The pyridine N atom of the cation in the title hydrated salt, C13H11N2 +·NO3 ?·H2O, is protonated; the N atom of the NH2 group shows a planar conformation. The former N atom is hydrogen bonded to a water mol­ecule. The amino group is involved in three N—H?O hydrogen bonds with two neighboring nitrate anions. The water mol­ecule is hydrogen bonded to two adjacent nitrate anions. In the crystal, this results in a layered network. PMID:21522328

Pourayoubi, Mehrdad; Eshtiagh-Hosseini, Hossein; Sanaei Ataabadi, Somayyeh; Mancilla Percino, Teresa; A. Leyva Ramírez, Marco

2011-01-01

286

Nitrate and Nitrite Reduction by Wolffia arrhiza.  

PubMed

Nitrate reductase was not found to be present in or associated with partially purified, intact chloroplasts aqueously isolated from Wolffia arrhiza. Such chloroplasts are capable of using nitrite but not nitrate as an electron acceptor during light-stimulated electron transport in the absence of additional cytoplasmic components. When nitrite acts as an electron acceptor under these conditions, on the average 1.5 moles of oxygen are evolved per mole of nitrite reduced by the chloroplasts, indicating a probable reduction of nitrite to ammonia. Chloroplasts ruptured by osmotic shock fail to reduce nitrite in the absence of additional components. PMID:16657592

Swader, J A; Stocking, C R

1971-02-01

287

Methylhydrazinium nitrate. [rocket plume deposit chemistry  

NASA Technical Reports Server (NTRS)

Methylhydrazinium nitrate was synthesized by the reaction of dilute nitric acid with methylhydrazine in water and in methanol. The white needles formed are extremely hygroscopic and melt at 37.5-40.5 C. The IR spectrum differs from that reported elsewhere. The mass spectrum exhibited no parent peak at 109 m/z, and thermogravimetric analysis indicated that the compound decomposed slowly at 63-103 C to give ammonium and methylammonium nitrate. The density is near 1.55 g/cu cm.

Lawton, E. A.; Moran, C. M.

1983-01-01

288

A Reservoir of Nitrate Beneath Desert Soils  

USGS Publications Warehouse

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.

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

2003-01-01

289

Interaction of uranium with nitrate melts  

SciTech Connect

Interaction of metallic uranium with a eutectic mixture of KNO/sub 3/-NaNO/sub 3/ melt at 234-510/sup 0/C in an inert atmosphere is studied. It is shown that the degree of uranium oxidation depends on the melt temperature. At 236-367/sup 0/C uranium dioxide is formed; the latter undergoes oxidation to diuranate at a higher temperature. The interaction is accompanied by accumulation of alkali metal nitrates in a nitrate melt and by NO/sub 2/ evolution.

Denisov, V.P.; Korobeinikov, I.V.; Kutyrev, K.N.; Pyatkov, V.I.; Raspopin, S.P.

1987-07-01

290

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

Microsoft Academic Search

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

D. J. Stuehr; M. A. Marletta

1985-01-01

291

Physicomechanical properties of the surface of a zirconium alloy modified by a pulsed ion beam  

NASA Astrophysics Data System (ADS)

The physicomechanical properties of the surface of the Zr-1% Nb zirconium alloy modified by a pulsed carbon ion beam with a pulse duration of 80 ns, an energy of 200 keV, and a current density of 120 A/cm2 are studied at four regimes having different numbers of pulses. Irradiation by a carbon ion beam results in hardening of the surface layer to a depth of 2 ?m, grain refinement to 0.15-0.8 ?m, zirconium carbide formation, and a decrease in the hydrogen permeability of the zirconium alloy.

Chernov, I. P.; Berezneeva, E. V.; Beloglazova, P. A.; Ivanova, S. V.; Kireeva, I. V.; Lider, A. M.; Remnev, G. E.; Pushilina, N. S.; Cherdantsev, Yu. P.

2014-04-01

292

CURRENT METHODS TO MEASURE ATMOSPHERIC NITRIC ACID AND NITRATE ARTIFACTS  

EPA Science Inventory

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

293

Perchlorate and nitrate in situ bioremediation of ground water  

SciTech Connect

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

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

2002-01-01

294

ORNL/TM-2008/048 Uranyl Nitrate Flow Loop  

E-print Network

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

Pennycook, Steve

295

Investigation of desert subsoil nitrate in Northeastern Badia of Jordan.  

PubMed

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

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

2013-01-01

296

Light-dark changes in cytosolic nitrate pools depend on nitrate reductase activity in Arabidopsis leaf cells.  

PubMed

Several different cellular processes determine the size of the metabolically available nitrate pool in the cytoplasm. These processes include not only ion fluxes across the plasma membrane and tonoplast but also assimilation by the activity of nitrate reductase (NR). In roots, the maintenance of cytosolic nitrate activity during periods of nitrate starvation and resupply (M. van der Leij, S.J. Smith, A.J. Miller [1998] Planta 205: 64-72; R.-G. Zhen, H.-W. Koyro, R.A. Leigh, A.D. Tomos, A.J. Miller [1991] Planta 185: 356-361) suggests that this pool is regulated. Under nitrate-replete conditions vacuolar nitrate is a membrane-bound store that can release nitrate to the cytoplasm; after depletion of cytosolic nitrate, tonoplast transporters would serve to restore this pool. To study the role of assimilation, specifically the activity of NR in regulating the size of the cytosolic nitrate pool, we have compared wild-type and mutant plants. In leaf mesophyll cells, light-to-dark transitions increase cytosolic nitrate activity (1.5-2.8 mm), and these changes were reversed by dark-to-light transitions. Such changes were not observed in nia1nia2 NR-deficient plants indicating that this change in cytosolic nitrate activity was dependent on the presence of functional NR. Furthermore, in the dark, the steady-state cytosolic nitrate activities were not statistically different between the two types of plant, indicating that NR has little role in determining resting levels of nitrate. Epidermal cells of both wild type and NR mutants had cytosolic nitrate activities that were not significantly different from mesophyll cells in the dark and were unaltered by dark-to-light transitions. We propose that the NR-dependent changes in cytosolic nitrate provide a cellular mechanism for the diurnal changes in vacuolar nitrate storage, and the results are discussed in terms of the possible signaling role of cytosolic nitrate. PMID:15908593

Cookson, Sarah J; Williams, Lorraine E; Miller, Anthony J

2005-06-01

297

Light-Dark Changes in Cytosolic Nitrate Pools Depend on Nitrate Reductase Activity in Arabidopsis Leaf Cells1[w  

PubMed Central

Several different cellular processes determine the size of the metabolically available nitrate pool in the cytoplasm. These processes include not only ion fluxes across the plasma membrane and tonoplast but also assimilation by the activity of nitrate reductase (NR). In roots, the maintenance of cytosolic nitrate activity during periods of nitrate starvation and resupply (M. van der Leij, S.J. Smith, A.J. Miller [1998] Planta 205: 64–72; R.-G. Zhen, H.-W. Koyro, R.A. Leigh, A.D. Tomos, A.J. Miller [1991] Planta 185: 356–361) suggests that this pool is regulated. Under nitrate-replete conditions vacuolar nitrate is a membrane-bound store that can release nitrate to the cytoplasm; after depletion of cytosolic nitrate, tonoplast transporters would serve to restore this pool. To study the role of assimilation, specifically the activity of NR in regulating the size of the cytosolic nitrate pool, we have compared wild-type and mutant plants. In leaf mesophyll cells, light-to-dark transitions increase cytosolic nitrate activity (1.5–2.8 mm), and these changes were reversed by dark-to-light transitions. Such changes were not observed in nia1nia2 NR-deficient plants indicating that this change in cytosolic nitrate activity was dependent on the presence of functional NR. Furthermore, in the dark, the steady-state cytosolic nitrate activities were not statistically different between the two types of plant, indicating that NR has little role in determining resting levels of nitrate. Epidermal cells of both wild type and NR mutants had cytosolic nitrate activities that were not significantly different from mesophyll cells in the dark and were unaltered by dark-to-light transitions. We propose that the NR-dependent changes in cytosolic nitrate provide a cellular mechanism for the diurnal changes in vacuolar nitrate storage, and the results are discussed in terms of the possible signaling role of cytosolic nitrate. PMID:15908593

Cookson, Sarah J.; Williams, Lorraine E.; Miller, Anthony J.

2005-01-01

298

Background-like nitrate in desert air  

NASA Astrophysics Data System (ADS)

The atmospheric nitrogen cycle is a key process driving the earth's environmental evolution. Current model studies require knowledge of NOx soil emissions from various land types, but desert emissions remain unquantified or are not addressed with high confidence. Our measurements at two observatories in Taklimakan desert during a dust episode showed an approximately stable and dust-independent nitrate in the air. Its concentration estimated from PM2.5, PM10 and TSP samples under non-dust, floating dust and dust storm conditions was 3.81 ± 1.24 ?g m-3, 2.95 ± 0.69 ?g m-3, 4.99 ± 1.71 ?g m-3, respectively, despite the more-than-one-order difference of dust loading. This concentration was much larger than that in remote marine and tropical forest air. Comprehensive investigation revealed a similar presence of nitrate in other desert air. The nitrate was hypothesized to be the consequence of the conversion of NOx released from desert soils. These results indicate a background-like nitrate and active reactions of nitrogen compounds in desert air.

Wu, Feng; Zhang, Daizhou; Cao, Junji; Zhang, Ting; An, Zhisheng

2014-02-01

299

A toxicological study of gadolinium nitrate  

SciTech Connect

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.

London, J.E.

1988-05-01

300

Iron, nitrate uptake by phytoplankton, and mermaids  

NASA Astrophysics Data System (ADS)

The critique 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.

Banse, Karl

1991-11-01

301

Iron, nitrate uptake by phytoplankton, and mermaids  

Microsoft Academic Search

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.

Karl Banse

1991-01-01

302

Denitration of High Nitrate Salts Using Reductants  

SciTech Connect

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

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

1999-05-03

303

Negative ion spectrometry for detecting nitrated explosives  

NASA Technical Reports Server (NTRS)

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

Boettger, H. G.; Yinon, J.

1975-01-01

304

Nitrate salt immobilization process development and implementation  

Microsoft Academic Search

The waste nitrate salts generated at the Rocky Flats Plant (RFP) were determined to be unacceptable in their present form for shipment to and storage at the Nevada Test Site, according to the recently implemented Waste Acceptance Criteria. A reduction in the dispersibility and oxidizing potential of the salt was necessary. Various methods of immobilization were investigated to determine the

R. D. Petersen; A. J. Johnson; K. G. Peter

1986-01-01

305

Some characteristics of nitrate reductase induction in Lemna minor L  

Microsoft Academic Search

Low levels of nitrate reductase can be detected in plants of Lemna minor grown on some organic nitrogen sources. Nitrogen-starvation does not lead to a derepression of nitrate reductase activity. Nitrate ions are necessary for the development of maximum enzyme activity and the maintenance of high enzyme levels. Nitrogen-starvation of ammonia-grown plants increases the subsequent rate of nitrate-mediated induction. It

T. O. Orebamjo; G. R. Stewart

1974-01-01

306

Ceric Ammonium Nitrate in Organic Synthesis III. A Facile Synthesis of Methoxylated 3, 4 Dihydroisoquinolinium Nitrates  

Microsoft Academic Search

A mild and efficient method for the synthesis of 3, 4-dihydroisoquinolinium salts, key intermediates for the preparation of isoquinoline alkaloïds, by an oxidation of N-methyl-1, 2, 3, 4-tetrahydroisoquinolines using ceric ammonium nitrate (CAN) is described.

Irinel Badea; Philippe Cotelle; Jean-Pierre Catteau

1995-01-01

307

Nitration of Electron-Rich Aromatic Compounds by Cerium Ammonium Nitrate Coated on Silica  

Microsoft Academic Search

Treatment of electron-rich aromatic derivatives with cerium (IV) ammonium nitrate coated on silica (CAN\\/Si02) affords nitro aromatic compounds. The scope and the limitation of this reaction are discussed.

Jean-Luc Grenier; Jean-Pierre Catteau; Philippe Cotelle

1999-01-01

308

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

NASA Technical Reports Server (NTRS)

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

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

1989-01-01

309

The nitrate\\/proton antiporter AtCLCa mediates nitrate accumulation in plant vacuoles  

Microsoft Academic Search

Nitrate, the major nitrogen source for most plants, is widely used as a fertilizer and as a result has become a predominant freshwater pollutant. Plants need nitrate for growth and store most of it in the central vacuole. Some members of the chloride channel (CLC) protein family, such as the torpedo-fish ClC-0 and mammalian ClC-1, are anion channels, whereas the

A. de Angeli; D. Monachello; G. Ephritikhine; J. M. Frachisse; S. Thomine; F. Gambale; H. Barbier-Brygoo

2006-01-01

310

Selective Nitrate Binding in Competitive Hydrogen Bonding Solvents: Do Anion-? Interactions Facilitate Nitrate Selectivity?**  

PubMed Central

New tripodal urea receptors demonstrate preferential binding of anions over competitive hydrogen bonding solvents. 1H NMR titrations in 10% DMSO-d6/CDCl3 show a higher affinity for nitrate over the halides for the fluorinated receptor, which is lost when the fluorines are removed. An “anion–?” interaction between the nitrate and the ?-system of the ethynyl-substituted arene is proposed as the source of this selectivity. PMID:23939999

Watt, Michelle M.; Zakharov, Lev N.

2013-01-01

311

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

Microsoft Academic Search

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

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

2004-01-01

312

Studies on Water Treatment for Removal of Nitrate  

Microsoft Academic Search

Groundwater studies in arid zones of Churu block and adjacent villages exhibit high nitrate concentrations which make the groundwater unsuitable for drinking. Though there are many nitrate remediation methods\\/products in market, these may not be feasible for use at rural level. This paper describes a preliminary investigation on nitrate remediation abilities of active neutral alumina, activated charcoal, agar, yellow mustard

Kavita Batheja; A. K. Sinha; Gita Seth

2009-01-01

313

Investigation of molten nitrate salt chemistry for solar receiver applications  

Microsoft Academic Search

Molten 60% sodium, 40% potassium nitrate salt mixtures were investigated for chemical and physical properties important to the design of a commercial solar receiver system. These properties are: nitrate-nitrite equilibrium with air, reactions with carbon dioxide and water vapor in air, in-situ regeneration of nitrates from decomposition products, and dynamic effects of a flowing, thermally cycled environment on salt properties.

D. W. Nelswander; T. J. Giordano; S. P. Prine

1981-01-01

314

NITRATE POLLUTION RISK ASSESSMENT: FROM THE MODEL TO THE INDICATOR  

E-print Network

study. INTRODUCTION Nitrate pollution is a threat to many of Europe's water resources, particularlyNITRATE POLLUTION RISK ASSESSMENT: FROM THE MODEL TO THE INDICATOR A. LACROIX 1 , F. LAURENT 2 , D. RUELLAND 3 , E. SAUBOUA 4 ABSTRACT The diffuse nature of nitrate pollution makes it difficult to evaluate

Paris-Sud XI, Université de

315

Ammonium inactivation of nitrate reductase in Lemna minor L  

Microsoft Academic Search

The addition of ammonium to nitrate induced plants of Lemna minor L. brings about a rapid loss in extractable nitrate reductase activity. This inactivation is reversible both in vivo and in vitro. Inhibitors of RNA and protein synthesis do not protect nitrate reductase against ammonium inactivation. It is suggested that factors, in addition to ammonium ions, are components of the

T. O. Orebamjo; G. R. Stewart

1975-01-01

316

Ammonium repression of nitrate reductase formation in Lemna minor L  

Microsoft Academic Search

The presence of ammonium is shown to inhibit the nitrate-promoted formation of nitrate reductase in Lemna minor L. The ammonium inhibition does not result from an inhibition of nitrate accumulation. The kinetics of the ammonium inhibition suggest it is not a direct effect of ammonium. The inhibition could result from the build up of a product of ammonium assimilation or

T. O. Orebamjo; G. R. Stewart

1975-01-01

317

Quantifying Nitrate Flux during Storm Events J. S. Herman1  

E-print Network

Quantifying Nitrate Flux during Storm Events J. S. Herman1 , A. L. Mills1 , G. M. Hornberger1 , A St, Philadelphia, PA 19104; e-mail: mira.s.olson@drexel.edu. Abstract Excess nitrate, mainly due to coastal waters, but there are many unanswered questions pertaining to nitrate flux during storm events

Virginia, University of

318

Evaporation of Ammonium Nitrate Aerosol in a Heated Nephelometer  

E-print Network

Evaporation of Ammonium Nitrate Aerosol in a Heated Nephelometer: Implications for Field National Laboratory, Upon, New York, 11973-5000 Ammonium nitrate is a semivolatile aerosol component under scattering coefficient of ammonium nitrate aerosol due to evaporation in a heated nephelometer. Changes

319

Turbulent nitrate fluxes in the Amundsen Gulf during icecovered conditions  

E-print Network

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

320

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

E-print Network

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

321

Fluorescence dynamics in supercooled (acetamide + calcium nitrate) molten mixtures  

E-print Network

Fluorescence dynamics in supercooled (acetamide + calcium nitrate) molten mixtures Harun Al Rasid­10]. Binary mixtures of acetamide and calcium nitrate tetrahydrate (m.p. $316 K) form a liquid near room.24 mol fraction of calcium nitrate indicates aggrega- tion of amide molecules in presence

Biswas, Ranjit

322

Factors controlling nitrate fluxes in groundwater in agricultural areas  

E-print Network

Factors controlling nitrate fluxes in groundwater in agricultural areas Lixia Liao,1 Christopher T affecting distribution of agricultural nitrate in groundwater, a parsimonious transport model was applied, L., C. T. Green, B. A. Bekins, and J. K. Bošhlke (2012), Factors controlling nitrate fluxes

323

Nitrate utilization and nitrogen status in English woodland communities  

E-print Network

Nitrate utilization and nitrogen status in English woodland communities E.C.M. Clough J. Pearson G- cies. The present study shows that leaf nitrate reduction is of common occurrence in woody plants of English woodland com- munities. Pioneer species tend to exhibit a greater capacity for leaf nitrate

Paris-Sud XI, Université de

324

LABORATORY EXPERIMENT 6 PRECIPITATION TITRATION WITH SILVER NITRATE.  

E-print Network

LABORATORY EXPERIMENT 6 PRECIPITATION TITRATION WITH SILVER NITRATE. The AgNO3 solution (~0.02 M in the titration of chloride ion with silver nitrate. The first excess of titrant results in the formation of a red Ag2CrO4. Calculations: From the volume of silver nitrate solution used fopr titration, calculate

Nazarenko, Alexander

325

LABORATORY EXPERIMENT 5 PRECIPITATION TITRATION WITH SILVER NITRATE.  

E-print Network

LABORATORY EXPERIMENT 5 PRECIPITATION TITRATION WITH SILVER NITRATE. The AgNO3 solution (~0.02 M in the titration of chloride ion with silver nitrate. The first excess of titrant results in the formation of a red Ag2CrO4. Calculations: From the volume of silver nitrate solution used fopr titration, calculate

Nazarenko, Alexander

326

Introduction Current methods to determine nitrate (NO3  

E-print Network

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

Sigman, Daniel M.

327

VOCs, Pesticides, Nitrate, and Their Mixtures in Groundwater Used for  

E-print Network

VOCs, Pesticides, Nitrate, and Their Mixtures in Groundwater Used for Drinking Water in the United areas. For each sample, as many as 60 volatile organic compounds (VOCs), 83 pesticides, and nitrate were analyzed. On the basis of previous studies, nitrate concentrations as nitrogen g3 mg/L were considered

328

Research Indicates Sprinkler Irrigation Use Could Reduce Groundwater Nitrate Levels  

E-print Network

Research Indicates Sprinkler Irrigation Use Could Reduce Groundwater Nitrate Levels by Steve Ress groundwater nitrate contamination, University of Nebraska research shows. Results from a six-year study sprinklers were used to irrigate crops, groundwater nitrate contamination could be significantly reduced

Nebraska-Lincoln, University of

329

Original article Ionic adsorption of ammonium and nitrate on some  

E-print Network

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

Paris-Sud XI, Université de

330

Original article A simple indicator for diagnosing nitrate leaching risk  

E-print Network

Original article A simple indicator for diagnosing nitrate leaching risk below the root zone using, France (Received 6 February 1998; accepted 8 September 1998) Abstract - Soil water potential and nitrate at three different sites for assessing nitrate leaching. The above measurements were made every 10 days

Paris-Sud XI, Université de

331

EUROPEAN LARGE LAKES III Identification of factors constraining nitrate assimilation  

E-print Network

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

Berges, John A.

332

Enhancement of nitrate reductase activity by benzyladenine in Agrostemma githago  

Microsoft Academic Search

Nitrate reductase activity in excised embryos of Agrostemma githago increases in response to both NOâ⁻ and cytokinins. Discussed was whether cytokinins affected nitrate reductase activity directly or through NOâ⁻, either by amplifying the effect of low endogenous NOâ⁻ levels, or by making NOâ⁻ available for induction from a metabolically inactive compartment. Nitrate reductase activity was enhanced on the average by

H. Kende; H. Hahn; S. E. Kays

1971-01-01

333

ORIGINAL ARTICLE Impact of elevated nitrate on sulfate-reducing  

E-print Network

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

Hazen, Terry

334

Waste Isolation Pilot Plant Nitrate Salt Bearing Waste Container  

E-print Network

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

Napp, Nils

335

The STICS model to predict nitrate leaching following agricultural practices  

E-print Network

The STICS model to predict nitrate leaching following agricultural practices Nathalie SCHNEBELENa-crop model STICS in order to predict the impact of agricultural practices on nitrate leaching on both plot and regional scales. A case study was carried out on a `Nitrate Vulnerable Zone' located in central France

Paris-Sud XI, Université de

336

Coupling the 15 O of nitrate as a constraint on  

E-print Network

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 incubationsĂ? 2 dĂ? 1 . Between 46% and 100% of the total denitrification can be explained by nitrate or nitrite

Sigman, Daniel M.

337

Article original Teneur en nitrate du lait. Relation  

E-print Network

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 phrĂ©atiques, conduit Ă  une augmentation sensible de la teneur en nitrate de l'eau d'abreuvement des vaches laitiĂšres et il faut donc

Paris-Sud XI, Université de

338

46 CFR 148.220 - Ammonium nitrate-phosphate fertilizers.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Ammonium nitrate-phosphate fertilizers. 148.220...Certain Materials § 148.220 Ammonium nitrate-phosphate fertilizers. (a...containing a maximum of 70 percent of ammonium nitrate and containing a maximum of 0.4...

2011-10-01

339

9 CFR 319.2 - Products and nitrates and nitrites.  

...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...

2014-01-01

340

46 CFR 148.220 - Ammonium nitrate-phosphate fertilizers.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Ammonium nitrate-phosphate fertilizers. 148.220...Certain Materials § 148.220 Ammonium nitrate-phosphate fertilizers. (a...containing a maximum of 70 percent of ammonium nitrate and containing a maximum of 0.4...

2013-10-01

341

9 CFR 319.2 - Products and nitrates and nitrites.  

Code of Federal Regulations, 2013 CFR

...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...

2013-01-01

342

9 CFR 319.2 - Products and nitrates and nitrites.  

Code of Federal Regulations, 2010 CFR

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

2010-01-01

343

9 CFR 319.2 - Products and nitrates and nitrites.  

Code of Federal Regulations, 2012 CFR

...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...

2012-01-01

344

46 CFR 148.220 - Ammonium nitrate-phosphate fertilizers.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Ammonium nitrate-phosphate fertilizers. 148.220...Certain Materials § 148.220 Ammonium nitrate-phosphate fertilizers. (a...containing a maximum of 70 percent of ammonium nitrate and containing a maximum of 0.4...

2012-10-01

345

9 CFR 319.2 - Products and nitrates and nitrites.  

Code of Federal Regulations, 2011 CFR

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

2011-01-01

346

Highly double selective nitration of nitrostilbenes over zeolite.  

PubMed

A feasible zeolite-assisted ortho C-H nitration of nitrostilbenes has been developed for the first time, which can be used in situ. It uses acetyl nitrate as a mild, easily handled and commercially available nitrating reagent, leading to the synthesis of polynitrostilbenes with double selectivities and in good yields. PMID:25083515

Xu, Jun-Hui; Wei, Jian-Ping; Hao, Zheng; Ma, Qing-Guo; Peng, Xin-Hua

2014-09-21

347

Anisole Nitration During Gamma-Irradiation of Aqueous Nitrite and Nitrate Solutions: Free Radical Versus Ionic Mechanisms  

SciTech Connect

The nitration of aromatic compounds in the condensed phase is of interest to nuclear waste treatment applications. This chapter discusses our investigation of radiolytic aromatic nitration mechanisms in the condensed phase toward understanding the nitration products created during nuclear fuel reprocessing. The nitration reactions of anisole, a model aromatic compound, were studied in ?-irradiated acidic nitrate, neutral nitrate, and neutral nitrite solutions. The nitrated anisole product distributions were the same with and without radiation in acidic solution, although more products were formed with radiation. In the irradiated acidic condensed phase, radiation-enhanced nitrous acid-catalyzed nitrosonium ion electrophilic aromatic substitution followed by oxidation reactions dominated over radical addition reactions. Neutral nitrate anisole solutions were dominated by mixed nitrosonium/nitronium ion electrophilic aromatic substitution reactions, but with lower product yields. Irradiation of neutral nitrite anisole solution resulted in a statistical substitution pattern for nitroanisole products, suggesting non-electrophilic free radical reactions involving the •NO2 radical.

Gracy Elias; Bruce J. Mincher; Leigh R. Martin; Stephen P. Mezyk; Thomas D. Cullen

2010-04-01

348

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

PubMed

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

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

2013-10-01

349

Electrochemical formation of uranium-zirconium alloy in LiCl-KCl melts  

NASA Astrophysics Data System (ADS)

Since zirconium is considered an electrochemically active species under practical conditions of the electrorefining process, it is crucial to understand the electrochemical behavior of zirconium in LiCl-KCl melts containing actinide ions. In this study, the electrochemical codeposition of uranium and zirconium on a solid cathode was performed. It was found that the ?-(U, Zr) phase, which is the only intermediate phase of the uranium-zirconium binary alloy system, was deposited on a tantalum substrate by potentiostatic electrolysis at -1.60 V (vs. Ag +/Ag) in LiCl-KCl melts containing 0.13 in mol% UCl 3 and 0.23 in mol% ZrCl 4 at 773 K. To our knowledge, this is the first report on the electrochemical formation of the ?-(U, Zr) phase. The relative partial molar properties of uranium in the ?-(U, Zr) phase were evaluated by measuring the open-circuit-potentials of the electrochemically prepared ?-phase electrode.

Murakami, Tsuyoshi; Kato, Tetsuya; Kurata, Masaki; Yamana, Hajimu

2009-11-01

350

Development of a plasma coating system for induction melting zirconium in a graphite crucible  

SciTech Connect

A plasma coating system has been developed for induction melting zirconium at 1900 C using a graphite crucible. This laminated coating system consists of plasma spraying the following materials onto the graphite: (1) molybdenum or tungsten, (2) a 50% blend by weight of the metal powder and calcia-stabilized zirconium oxide, and (3) calcia-stabilized zirconia followed by painting a final coating of nonstabilized zirconia on top of the plasma-sprayed coating system. Zirconium was melted in argon using both laminating systems without any degradation of the graphite crucible and with only a minimal amount of carbon absorption. This novel approach that is being proposed as an alternative method of melting zirconium alloys offers substantial cost savings over the standard practice of electric arc melting using a consumable electrode.

Bird, E.L.; Holcombe, C.E. Jr.

1993-05-26

351

Effects of carbon and nitrate additions to soil upon leaching of nitrate, microbial predators and nitrogen uptake by plants  

Microsoft Academic Search

Amendments with glucose significantly reduced the amount of nitrate leached from a sandy soil amended with nitrate. The decrease\\u000a was most likely caused by immobilisation of the nitrate into microbial cells. Populations of ciliates and flagellates and\\u000a amoebae, but not nematodes, increased 7–14 days following glucose amendments. Mineralisation of the immobilised nitrate occurred\\u000a during this period. Some of the mineralised

Karl Ritz; Bryan S. Griffiths

1987-01-01

352

Quantum molecular dynamics simulation of hydrogen diffusion in zirconium hydride  

NASA Astrophysics Data System (ADS)

The behavior of hydrogen in zirconium hydride in the high-temperature range has been investigated using the quantum molecular dynamics method. The ? phases of compositions ZrH1.75 and ZrH2 and the liquid phase are considered. The self-diffusion coefficients of hydrogen are calculated as a function of the temperature in the range from 1000 to 6000 K. For the ZrH1.75 and ZrH2 hydrides, the obtained values are close to each other. At temperatures of 1000-2000 K, the hydrogen diffusion is determined not only by the mobility of hydrogen atoms but also by the transition from the energetically favorable tetrahedral positions into the excited state. The obtained values of the diffusion coefficients in the temperature range of 1000-1200 K are in good agreement with the experimental data.

Yanilkin, A. V.

2014-09-01

353

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

NASA Technical Reports Server (NTRS)

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.

2003-01-01

354

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

NASA Technical Reports Server (NTRS)

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.

2003-01-01

355

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

E-print Network

EVALUATION OF ZIRCONIUM-IRON-RHENIUM ALLOYS AS SURROGATES FOR A TECHNETIUM ALLOY WASTE FORM A Thesis by PAUL AARON MEWS Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE December 2007 Major Subject: Nuclear Engineering EVALUATION OF ZIRCONIUM-IRON-RHENIUM ALLOYS AS SURROGATES FOR A TECHNETIUM ALLOY WASTE FORM A Thesis by PAUL AARON MEWS Submitted...

Mews, Paul Aaron

2008-10-10

356

A simple route for organic covalent grafting onto zirconium carbide particles  

NASA Astrophysics Data System (ADS)

Starting from core-shell zirconium carbide powders, a covalent grafting was described, using a direct nucleophilic substitution in diethyl ether. Thus, two different organic molecules were attached onto the surface of the ceramic, through Sisbnd Osbnd Zr and Csbnd Osbnd Zr bonds. The materials were characterized by means of TEM and XPS characterizations. These new systems could represent an original route to elaborate zirconium carbide-based hybrid materials.

Lucas, Romain; Pizon, David; Laborde, Etienne; Trolliard, Gilles; Foucaud, Sylvie; Maître, Alexandre

2013-12-01

357

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

SciTech Connect

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.

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

1996-01-01

358

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

SciTech Connect

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

G. A. Moore; M. C. Marshall

2010-01-01

359

Esterification of Stearic Acid with Triethanolamine over Zirconium Sulfate Supported on SBA15 Mesoporous Molecular Sieve  

Microsoft Academic Search

Zirconium sulfate supported on SBA-15 (pore diameter about 6 nm) mesoporous molecular sieve was synthesized. Various techniques,\\u000a such as nitrogen adsorption–desorption isotherms, X-ray diffraction, transmission electron microscopy, and temperature-programmed\\u000a desorption, were used to characterize the prepared catalysts. It was shown that the catalyst exhibited straight, parallel,\\u000a and uniform channels, zirconium sulfate had been finely dispersed on the surface of SBA-15, and

Tao Geng; Qiuxiao Li; Yajie Jiang; Wei Wang

2011-01-01

360

Activated carbons modified with aluminium–zirconium polycations as adsorbents for ammonia  

Microsoft Academic Search

Microporous\\/mesoporous wood-based activated carbon was modified by impregnation with aluminium–zirconium oxycations and calcined at 300°C, and then used as an adsorbent of ammonia. Water was present either on the carbon or in the gas phase. The initial (before ammonia adsorption) and exhausted materials were characterized using adsorption of nitrogen, potentiometric titration, XRD, FTIR and thermal analysis. Aluminium–zirconium polycations improve ammonia

Camille Petit; Teresa J. Bandosz

2008-01-01

361

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

Microsoft Academic Search

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

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

2006-01-01

362

Nitrate leaching in an Atlantic Coastal Plain soil amended with poultry manure or urea-ammonium nitrate: Influence of thiosulfate  

Microsoft Academic Search

Nitrate leaching, which can lead to groundwater contamination, is a common occurrence, especially in sandy, well drained soils. Nitrogen from poultry manure (PM) and ammonium fertilizers has been shown to undergo rapid nitrification upon addition to soils, making it highly susceptible to nitrate leaching. Any management technique that could delay nitrification and thereby reduce nitrate leaching would be desirable. Ammonium

Y. E. Sallade; J. T. Sims

1994-01-01

363

Nitrate, nitrate reduction and organic nitrogen in plants from different ecological and taxonomic groups of Central Europe  

Microsoft Academic Search

48 plant species of the families Asteraceae, Chenopodiaceae, Ericaceae, Fabaceae, Lamiaceae, Polygonaceae and Urticaceae were investigated in 14 natural habitats of Central Europe having different nitrate supplies, with respect to their nitrate content, nitrate reductase activity (NRA) and organic nitrogen content. Plants that were flowering were selected where possible for analysis. The plants were subdivided into flowers, laminae, petioles+shoot axes

G. Gebauer; H. Rehder; B. Wollenweber

1988-01-01

364

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

E-print Network

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

Li, Zhanqing

365

Mechanical resistance of zirconium implant abutments: A review of the literature  

PubMed Central

The increase of aesthetic demands, together with the successful outcome of current implants, has renewed interest in the search for new materials with enough mechanical properties and better aesthetic qualities than the materials customarily used in implanto-prosthetic rehabilitation. Among these materials, zirconium has been used in different types of implants, including prosthetic abutments. The aim of the present review is to analyse current scientific evidence supporting the use of this material for the above mentioned purposes. We carried out the review of the literature published in the last ten years (2000 through 2010) of in vitro trials of dynamic and static loading of zirconium abutments found in the databases of Medline and Cochrane using the key words zirconium abutment, fracture resistance, fracture strength, cyclic loading. Although we have found a wide variability of values among the different studies, abutments show favourable clinical behaviour for the rehabilitation of single implants in the anterior area. Such variability may be explained by the difficulty to simulate daily mastication under in vitro conditions. The clinical evidence, as found in our study, does not recommend the use of implanto-prosthetic zirconium abutments in the molar area. Key words: Zirconium abutment, zirconium implant abutment, zirconia abutment, fracture resistance, fracture strength, cyclic loading. PMID:22143702

Vaquero-Aguilar, Cristina; Torres-Lagares, Daniel; Jimenez-Melendo, Manuel; Gutierrez-Perez, Jose L.

2012-01-01

366

Nucleophilic attack on eta/sup 2/-acyls of zirconium. The synthesis and reactivity of zirconium ketone complexes  

SciTech Connect

The reaction of Cp/sub 2/ZrMe/sub 2/ with the eta/sup 2/-acyl complex, Cp/sub 2/Zr(C(O)Me)(/sup +/-OC)Mo(CO)/sub 2/Cp, produced the bridging ketone complex 4. The nucleophilic Ar-CH/sub 3/ added 1,2 across the C-O bond of the acyl group to generate an acetone ligand which was coordinated through the ketone oxygen to one Zr center and through both the ketone carbon and oxygen to the other Zr center. The crystal structure of 4 was reported. Ancillary ligand effects were investigated on the susceptibility of zirconocene eta/sup 2/-acyls to attack by Cp/sub 2/ZrMe/sub 2/, and on the ability of zirconocene methyl complexes to act as nucleophiles. Nucleophilic attack by Cp/sub 2/ZrMe/sub 2/ at the carbon of a eta/sup 2/-acyl was favored by the presence of a strong sigma-donor with limited ..pi..-donor ability. Methyl transfer from a zirconocene methyl complex was favored by the presence of similar ancillary substitution. Reactions of standard organometallic nucleophiles with zirconium eta/sup 2/-acyls was investigated as a route to new ketone complexes. The presence of ..cap alpha..-protons on the acyl group resulted in its deprotonation to known ketene complexes. The absence of ..cap alpha..-protons on the acyl group permitted the use of RLi reagents to synthesize new zirconium ketone complexes. The reactivity of complex 4 towards insertion, radical addition and attack by nucleophilic and electrophilic reagents was investigated. The crystal structure of the product of CO insertion into the ketone ligand was reported.

Matchett, S.A.

1986-01-01

367

Thermal decomposition hazard evaluation of hydroxylamine nitrate.  

PubMed

Hydroxylamine nitrate (HAN) is an important member of the hydroxylamine family and it is a liquid propellant when combined with alkylammonium nitrate fuel in an aqueous solution. Low concentrations of HAN are used primarily in the nuclear industry as a reductant in nuclear material processing and for decontamination of equipment. Also, HAN has been involved in several incidents because of its instability and autocatalytic decomposition behavior. This paper presents calorimetric measurement for the thermal decomposition of 24 mass% HAN/water. Gas phase enthalpy of formation of HAN is calculated using both semi-empirical methods with MOPAC and high-level quantum chemical methods of Gaussian 03. CHETAH is used to estimate the energy release potential of HAN. A Reactive System Screening Tool (RSST) and an Automatic Pressure Tracking Adiabatic Calorimeter (APTAC) are used to characterize thermal decomposition of HAN and to provide guidance about safe conditions for handling and storing of HAN. PMID:16154263

Wei, Chunyang; Rogers, William J; Mannan, M Sam

2006-03-17

368

Groundwater pollution by nitrates from livestock wastes  

SciTech Connect

Utilization of wastes from livestock complexes for irrigation involves the danger of groundwater pollution by nitrates. In order to prevent and minimize pollution, it is necessary to apply geological-hydrogeological evidence and concepts to the situation of wastewater irrigation for the purposes of studying natural groundwater protectiveness and predicting changes in groundwater quality as a result of infiltrating wastes. The procedure of protectiveness evaluation and quality prediction is described. With groundwater pollution by nitrate nitrogen, the concentration of ammonium nitrogen noticeably increases. One of the reasons for this change is the process of denitrification due to changes in the hydrogeochemical conditions in a layer. At representative field sites, it is necessary to collect systematic stationary observations of the concentrations of nitrogenous compounds in groundwater and changes in redox conditions and temperature.

Goldberg, V.M. (All-Union Research Institute of Hydrogeology and Engineering Geology, Moscow (USSR))

1989-11-01

369

Groundwater pollution by nitrates from livestock wastes.  

PubMed Central

Utilization of wastes from livestock complexes for irrigation involves the danger of groundwater pollution by nitrates. In order to prevent and minimize pollution, it is necessary to apply geological-hydrogeological evidence and concepts to the situation of wastewater irrigation for the purposes of studying natural groundwater protectiveness and predicting changes in groundwater quality as a result of infiltrating wastes. The procedure of protectiveness evaluation and quality prediction is described. With groundwater pollution by nitrate nitrogen, the concentration of ammonium nitrogen noticeably increases. One of the reasons for this change is the process of denitrification due to changes in the hydrogeochemical conditions in a layer. At representative field sites, it is necessary to collect systematic stationary observations of the concentrations of nitrogenous compounds in groundwater and changes in redox conditions and temperature. PMID:2620669

Goldberg, V M

1989-01-01

370

A Proteomic Study of Protein Tyrosine Nitration  

E-print Network

amino acid sequence.......................................... 26 3. In-vivo proteomic study of nitrated proteins in cardiac tissue as a function of aging Figure 3.1 SDS-PAGE and Western blot analysis of whole heart homogenates from 4 different...-peroxide-conjugated antibody was purchased from Pierce Biotechnology (Rockford, IL). ECL-Plus reagents were purchased from GE Healthcare (Piscataway, NJ). Powdered milk was purchased from Nestl?-Carnation (Glendale, CA). Polyvinylidine fluoride (PVDF) membranes were...

Hong, Sung Jung

2008-08-28

371

Pyrolysis of Waste Tires with Copper Nitrate  

Microsoft Academic Search

Influence of copper(?)nitrate(CN) on the pyrolysis of waste tires in 50 cm static batch reactor in a nitrogen atmosphere are studied. The products of pyrolysis was investigated with in situ Fourier transform infrared (FT-IR) spectroscopy as well as off-line gas chromatography\\/Mass spectrometry (GC-MS). The combination of FT-IR and GC\\/MS analysis was able to elucidate the effects of CN. Comparing with

QING-CAO KE-CHANG XIE; WEI-REN BAO; WEI-HUANG; JIAN-BING ZHAO

2004-01-01

372

Antiinflammatory activity of topically applied sertaconazole nitrate.  

PubMed

The antiinflammatory activity of topically applied sertaconazole nitrate was investigated. The dermal administration of 2% sertaconazole to rats, in which edema was induced by application of croton oil in the external ear, induced a 39.8% reduction of edema. The results show that sertaconazole applied by topical route at the concentration at which it is used in clinic, has antiinflammatory action in this experimental model. PMID:8803954

Agut, J; Tarrida, N; Sacristán, A; Ortiz, J A

1996-05-01

373

Equation of State of Ammonium Nitrate  

NASA Astrophysics Data System (ADS)

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.

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

2009-12-01

374

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

PubMed

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

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

375

Cold-surface photochemistry of selected organic nitrates.  

PubMed

Reflection-absorption infrared (RAIR) spectroscopy has been used to explore the low temperature condensed-phase photochemistry of atmospherically relevant organic nitrates for the first time. Three alkyl nitrates, methyl, isopropyl, and isobutyl nitrate together with a peroxyacyl nitrate, peroxyacetyl nitrate (PAN), were examined. For the alkyl nitrates, similar photolysis products were observed whether they were deposited neat to the gold substrate or codeposited with water. In addition to peaks associated with the formation of an aldehyde/ketone and NO, a peak near 2230 cm(-1) was found to emerge in the RAIR spectra upon UV photolysis of the thin films. Together with evidence obtained by thermal programmed desorption (TPD), the peak is attributed to the formation of nitrous oxide, N2O, generated as a product during the photolysis. On the basis of the known gas-phase photochemistry for the alkyl nitrates, an intermediate pathway involving the formation of nitroxyl (HNO) is proposed to lead to the observed N2O photoproduct. For peroxyacetyl nitrate, CO2 was observed as a predominant product upon photolytic decomposition. In addition, RAIR absorptions attributable to the formation of methyl nitrate were also found to appear upon photolysis. By analogy to the known gas-phase and matrix-isolated-phase photochemistry of PAN, the formation of methyl nitrate is shown to likely result from the combination of alkoxy radicals and nitrogen dioxide generated inside the thin films during photolysis. PMID:25232898

O'Sullivan, Daniel; McLaughlin, Ryan P; Clemitshaw, Kevin C; Sodeau, John R

2014-10-23

376

Actinide partitioning from actual ICPP dissolved zirconium calcine using the TRUEX solvent  

SciTech Connect

The TRansUranic EXtraction process (TRUEX), as developed by E.P. Horwitz and coworkers at Argonne National Laboratory (ANL), is being evaluated as a TRU extraction process for Idaho Chemical Processing Plant (ICPP) wastes. A criteria that must be met during this evaluation, is that the aqueous raffinate must be below the 10 nCi/g limit specified in 10 CFR 61.55. A test was performed where the TRUEX solvent (0.2 M octyl(phenyl)-N-N-diisobutyl-carbamoylmethyl-phosphine oxide (CMPO), and 1.4 M tributylphosphate (TBP) in an Isopar-L diluent) was contacted with actual ICPP dissolved zirconium calcine. Two experimental flowsheets were used to determine TRU decontamination factors, and TRU, Zr, Fe, Cr, and Tc extraction, scrub, and strip distribution coefficients. Results from these two flowsheets show that >99.99% of the TRU alpha activity was removed from the acidic feed after three contacts with the TRUEX solvent (fresh solvent being used for each contact). The resulting aqueous raffinate solution contained an approximate TRU alpha activity of 0.02 nCi/g, which is well below the non-TRU waste limit of 10 nCi/g specified in 10 CFR 61.55. Favorable scrub and strip distribution coefficients were also observed for Am-241, Pu-238, and Pu-239, indicating the feasibility of recovering these isotopes from the TRUTEX solvent. A solution of 0.04 M 1-hydroxyethane-1,1-diphosphonic acid (HEDPA) in 0.04 M HNO{sub 3} was used to successfully strip the TRUs from the TRUEX solvent. The results of the test using actual ICPP dissolved zirconium calcine, and subsequent GTM evaluation, show the feasibility of removing TRUs from the dissolved zirconium calcine with the TRUEX solvent and the deleterious effects zirconium poses with the ICPP zirconium calcine waste. Test results using actual ICPP zirconium calcine reveal the necessity of preventing zirconium from following the TRUs.

Brewer, K.N.; Herbst, R.S.; Tranter, T.J. [and others

1995-05-01

377

Evaluating nitrate sources in nested agricultural sub-basins using nitrate stable isotopes  

NASA Astrophysics Data System (ADS)

Nutrient enrichment is the second leading cause of drinking water contamination in the United States. To provide environmental managers with nutrient source and transport information, the U.S. Geological Survey' s National Water-Quality Assessment (NAWQA) Program conducted a multi-component study in Sugar Creek Basin, Indiana, in which major nutrients, cations, anions, and pesticides were analyzed. Land use at Sugar Creek (246 square km basin) is dominated by row crop agriculture, primarily corn and soybeans. The soils are largely heavy clay, glacial till in origin, and require tile drains to move excess water and make the land farmable. As one component of the study, stable isotopes of nitrate (N-15 and O-18) were used to examine nitrate sources and transport, and possible transformations of nitrate. Water samples were collected in 2003 and 2004 from major environmental compartments involved with the movement of nutrients into the creek, (precipitation, tile drain, and overland flow). Samples were also collected from Leary-Weber Ditch, a 6.2 square km basin is nested within Sugar Creek. Collection times bracketing four distinct periods of the agricultural cycle: pre-application of fertilizer, post-application of fertilizer, growing season, and post-harvest periods. Nutrient samples (nitrate, phosphate, ammonia) were also collected several times between storm events during baseflow conditions. Preliminary nutrient and pesticide data indicate that tile drains are the primary pathway into streams. Little interaction occurs between the ground water and surface water interface. Nitrate stable isotopes will enable us to determine the relative contribution of nitrate sources feeding in from the tile drains, into Leary-Weber Ditch and Sugar Creek.

Chang, C. C.; Frey, J. W.; Kim, M.; Kendall, C.

2005-05-01

378

Synthesis and liquid crystal phase transitions of zirconium phosphate disks  

NASA Astrophysics Data System (ADS)

Solvent-mediated self-assembly of nanoparticles is an effective and efficient way for the bottom-up organization of functional structures. The primary object of this work is to build up a model system for the study of suspensions of disk-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. Systematic experiments revealed that regular-shaped alpha-zirconium phosphate crystalline disks with a size-to-thickness ratio from 1 to 50 and size polydispersity as low as 0.2 can be obtained through hydrothermal treatment in 3 M to 15 M phosphoric acid solutions. Transmission and scanning electron micrographs revealed that the growth of the disks is mediated by oriented attachment, which happened continuously throughout the hydrothermal treatment between various sized disks. Ostwald ripening is effective in improving the regularity of the shape of the disks, especially under prolonged hydrothermal treatment. Under the microwave assisted hydrothermal conditions, the rate of attachment on the flat surfaces of the disks is accelerated, which leads to the formation of the column-shaped crystals. With the ability to adjust the size, aspect ratio, and polydispersity of ZrP disks, the study on self-assembly behavior and the discotic liquid crystal phases was enabled. Firstly, liquid crystal phases of aqueous suspensions of ZrP disks were investigated. Iridescent smectic phase and the critical points of phase transitions were found. Moreover, monolayer ZrP nanosheets with extremely high aspect ratio, which were achieved by exfoliating the ZrP crystals, were also used in this study. The high aspect ratio of nanosheets produces a laminar phase at low nanosheet concentration. Chiral liquid crystal phases were demonstrated when increased the concentration of the nanosheets. The competition between the chirality and layering leads to twisted and layered structures. For the final part, solvent-mediated self-assembly of disks and nanosheets via undulation of liquid crystal phases showed an interesting approach for bottom-up design of functional nano-structures.

Shuai, Min

379

Anisole nitration during gamma-irradiation of aqueous nitrite and nitrate solutions: Free radical versus ionic mechanisms  

SciTech Connect

Radiolytic aromatic nitration mechanisms in the condensed phase are ubiquitous, and especially of interest in atmospheric aerosol chemistry, water treatment by advanced oxidation technologies, and nuclear fuel reprocessing. Here, the radiolytically-induced nitration reactions of anisole, the simplest aryl alkyl ether, were investigated in ?-irradiated acidic nitrate solution, and in neutral nitrate and nitrite solutions. The nitrated anisole product distribution was the same with and without radiation in acidic solution, although more products were formed as a result of irradiation. This suggests that the mechanism of nitration in acidic solution is nitronium ion- induced electrophilic aromatic substitution. The rate of production of nitrated products in neutral nitrate solution was much lower, although the distribution of isomers was similar to that expected for nitronium ion electrophilic nitration. In contrast, the product distribution in neutral nitrite solution approached a statistically random substitution pattern, suggesting a non-electrophilic free radical reaction involving •NO2 radical. When hydroxyl radical (•OH) was scavenged by varying the initial nitrite concentration, the concentration of nitrated products increased with increasing nitrite, indicating that the reaction was probably one of direct •NO2 radical addition. However, this latter mechanism will not be important in acidic solutions, such as those often encountered in atmospheric aerosols or ?-irradiated nuclear fuel reprocessing solutions, due to low amounts of produced •NO2 radical and the low reaction rate constants for the •NO2 radical with aromatic compounds.

Gracy Elias; Bruce J. Mincher; Leigh R. Martin; Stephen P. Mezyk; Thomas Cullen

2010-04-01

380

Nitrate sources and sinks in Elkhorn Slough, California: Results from long-term continuous in situ nitrate analyzers  

USGS Publications Warehouse

Nitrate and water quality parameters (temperature, salinity, dissolved oxygen, turbidity, and depth) were measured continuously with in situ NO 3 analyzers and water quality sondes at two sites in Elkhorn Slough in Central California. The Main Channel site near the mouth of Elkhorn Slough was sampled from February to September 2001. Azevedo Pond, a shallow tidal pond bordering agricultural fields further inland, was sampled from December 1999 to July 2001. Nitrate concentrations were recorded hourly while salinity, temperature, depth, oxygen, and turbidity were recorded every 30 min. Nitrate concentrations at the Main Channel site ranged from 5 to 65 ??M. The propagation of an internal wave carrying water from ???100 m depth up the Monterey Submarine Canyon and into the lower section of Elkhorn Slough on every rising tide was a major source of nitrate, accounting for 80-90% of the nitrogen load during the dry summer period. Nitrate concentrations in Azevedo Pond ranged from 0-20 ??M during the dry summer months. Nitrate in Azevedo Pond increased to over 450 ??M during a heavy winter precipitation event, and interannual variability driven by differences in precipitation was observed. At both sites, tidal cycling was the dominant forcing, often changing nitrate concentrations by 5-fold or more within a few hours. Water volume flux estimates were combined with observed nitrate concentrations to obtain nitrate fluxes. Nitrate flux calculations indicated a loss of 4 mmol NO3 m -2 d-1 for the entire Elkhorn Slough and 1 mmol NO 3 m-2 d-1 at Azevedo Pond. These results suggested that the waters of Elkhorn Slough were not a major source of nitrate to Monterey Bay but actually a nitrate sink during the dry season. The limited winter data at the Main Channel site suggest that nitrate was exported from Elkhorn Slough during the wet season. Export of ammonium or dissolved organic nitrogen, which we did not monitor, may balance some or all of the NO 3 flux.

Chapin, T. P.; Caffrey, J. M.; Jannasch, H. W.; Coletti, L. J.; Haskins, J. C.; Johnson, K. S.

2004-01-01

381

Compartmental nitrate concentrations in barley root cells measured with nitrate-selective microelectrodes and by single-cell sap sampling.  

PubMed

Nitrate-selective microelectrodes were used to measure intracellular nitrate concentrations (as activities) in epidermal and cortical cells of roots of 5-d-old barley (Hordeum vulgare L.) seedlings grown in nutrient solution containing 10 mol · m(-3) nitrate. Measurements in each cell type grouped into two populations with mean (±SE) values of 5.4 ± 0.5 mol · m(-3) (n=19) and 41.8 ± 2.6 mol · m(-3) (n = 35) in epidermal cells, and 3.2 ± 1.2 mol · m(-3) (n = 4) and 72.8 ± 8.4 mol · m(-3) (n = 13) in cortical cells. These could represent the cytoplasmic and vacuolar nitrate concentrations, respectively, in each cell type. To test this hypothesis, a single-cell sampling procedure was used to withdraw a vacuolar sap sample from individual epidermal and cortical cells. Measurement of the nitrate concentration in these samples by a fluorometric nitrate-reductase assay confirmed a mean vacuolar nitrate concentration of 52.6 ± 5.3 mol · m(-3) (n = 10) in epidermal cells and 101.2 ± 4.8 mol · m(-3) (n = 44) in cortical cells. The nitrate-reductase assay gave only a single population of measurements in each cell type, supporting the hypothesis that the higher of the two populations of electrode measurements in each cell type are vacuolar in origin. Differences in the absolute values obtained by these methods are probably related to the fact that the nitrate electrodes were calibrated against nitrate activity but the enzymic assay against concentration. Furthermore, a 28-h time course for the accumulation of nitrate measured with electrodes in epidermal cells showed the apparent cytoplasmic measurements remained constant at 5.0 ± 0.7 mol · m(-3), while the vacuole accumulated nitrate to 30-50 mol · m(-3). The implications of the data for mechanisms of nitrate transport at the plasma membrane and tonoplast are discussed. PMID:24186418

Zhen, R G; Koyro, H W; Leigh, R A; Tomos, A D; Miller, A J

1991-10-01

382

Glucose elevates NITRATE TRANSPORTER2.1 protein levels and nitrate transport activity independently of its HEXOKINASE1-mediated stimulation of NITRATE TRANSPORTER2.1 expression.  

PubMed

Mineral nutrient uptake and assimilation is closely coordinated with the production of photosynthate to supply nutrients for growth. In Arabidopsis (Arabidopsis thaliana), nitrate uptake from the soil is mediated by genes encoding high- and low-affinity transporters that are transcriptionally regulated by both nitrate and photosynthate availability. In this study, we have studied the interactions of nitrate and glucose (Glc) on gene expression, nitrate transport, and growth using glucose-insensitive2-1 (gin2-1), which is defective in sugar responses. We confirm and extend previous work by showing that HEXOKINASE1-mediated oxidative pentose phosphate pathway (OPPP) metabolism is required for Glc-mediated NITRATE TRANSPORTER2.1 (NRT2.1) expression. Treatment with pyruvate and shikimate, two products derived from intermediates of the OPPP that are destined for amino acid production, restores wild-type levels of NRT2.1 expression, suggesting that metabolites derived from OPPP metabolism can, together with Glc, directly stimulate high levels of NRT2.1 expression. Nitrate-mediated NRT2.1 expression is not influenced by gin2-1, showing that Glc does not influence NRT2.1 expression through nitrate-mediated mechanisms. We also show that Glc stimulates NRT2.1 protein levels and transport activity independently of its HEXOKINASE1-mediated stimulation of NRT2.1 expression, demonstrating another possible posttranscriptional mechanism influencing nitrate uptake. In gin2-1 plants, nitrate-responsive biomass growth was strongly reduced, showing that the supply of OPPP metabolites is essential for assimilating nitrate for growth. PMID:24272701

de Jong, Femke; Thodey, Kate; Lejay, Laurence V; Bevan, Michael W

2014-01-01

383

Sulfate and nitrate collected by filter sampling near the tropopause  

NASA Technical Reports Server (NTRS)

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

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

1980-01-01

384

Strain effects on oxygen transport in tetragonal zirconium dioxide.  

PubMed

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. PMID:24127018

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

2013-11-28

385

Zirconium umbelliferonephosphate - A luminescent organic-inorganic hybrid nanomaterial  

NASA Astrophysics Data System (ADS)

Zirconium umbelliferonephosphate (ZrO(UFP)) is prepared by nucleation in the ionic liquid [MeBu 3N][NTf 2]. According to electron microscopy the resulting nanoparticles exhibit mean particle diameters of about 50 nm. The organic-inorganic hybrid material ZrO(UFP) shows blue emission upon UV-excitation. Luminescence originates from the organic dye and is highly intense due to the molar amount of luminescent centers per nanoparticle. The as-prepared material turns out to be non-crystalline. Therefore, its chemical composition is validated by infrared spectroscopy, thermogravimetry, energy-dispersive X-ray analysis and elemental analysis. The results (i.e., thermal decomposition, Zr:P ratio, C-/H-concentration) are in accordance to the composition of ZrO(UFP). Upon addition of acid phosphatase the luminescence intensity of ZrO(UFP) is significantly increased due to enzymatic hydrolysis accompanied by a release of non-bound umbelliferone. Both aspects - the increase in luminescence intensity as well as the release of umbelliferone - might be of future interest regarding biomedical application of ZrO(UFP) nanoparticles.

Roming, Marcus; Feldmann, Claus

2011-03-01

386

Microstructure and mechanical properties of proton irradiated zirconium carbide  

NASA Astrophysics Data System (ADS)

Zirconium carbide is a candidate ceramic being considered for metal-carbide-base composite-type fuels, as well as for an alternative coating material for TRISO particle fuels. Ensuring adequate mechanical properties and dimensional stability in response to radiation is a key part in developing a practical ZrC-base fuel. The existing available radiation response data for ZrC is limited and insufficient. In the present study, ZrC was irradiated with a 2.6 MeV proton beam at 800 °C to doses of 0.7 and 1.5 dpa. Following radiation, the radiation induced damage microstructure is comprised of a high density of nanometer-sized Frank loops, but no irradiation induced amorphization, voids, or precipitates were observed. A slight lattice expansion was found in the irradiated ZrC, in good agreement with the reported results from neutron irradiation. The changes in microhardness and fracture toughness properties induced in the irradiated samples were measured using indentation techniques. The hardness and the fracture toughness both increase with increasing radiation dose.

Yang, Yong; Dickerson, Clayton A.; Swoboda, Hannah; Miller, Brandon; Allen, Todd R.

2008-09-01

387

Biologically functionalized nanochannels on ferroelectric lead zirconium titanate surfaces.  

SciTech Connect

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

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

2005-01-01

388

The thermophysical properties of calcium and barium zirconium phosphate  

NASA Astrophysics Data System (ADS)

The thermophysical and structural properties of calcium and barium zirconium phosphate ceramics (CZP and BZP) have been investigated for their potential candidacy as actinide hosts for inert matrix fuels (IMF) in nuclear reactors. These phosphate ceramics, which can accommodate minor actinides as well as the resulting fission products, are found to be thermally stable to 1600 °C in air, however they begin to decompose in an inert atmosphere above approximately 1400 °C. The heat capacity, thermal conductivity and bulk thermal-expansion were measured from room temperature up to 1200 °C. Structural changes in this temperature region as well as the anisotropic thermal-expansion behaviour were studied using high-temperature X-ray diffraction. A phase change from R-3 to R-3c was identified for Ba0.5Zr2(PO4)3 near 880 °C. The thermal conductivity for these ceramics at 1000 °C was found to be 1.0 W m-1 K-1, a relatively low thermal conductivity that was increased to 5.0 W m-1 K-1 at 1000 °C for BZP:Ni (25:75 mass ratio) cermet composites.

Gregg, Daniel J.; Karatchevtseva, Inna; Triani, Gerry; Lumpkin, Gregory R.; Vance, Eric R.

2013-10-01

389

Synthesis and Characterization of Zirconium Tungstate Ultra-Thin Fibers  

SciTech Connect

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

Zhang, Lifeng [South Dakota School of Mines and Technology; Howe, Jane Y [ORNL; Fong, Hao [South Dakota School of Mines and Technology; Zhang, Yan [Anhui Normal University, People's Republic of China

2009-01-01

390

Characterization of zirconium thin films deposited by pulsed laser deposition  

NASA Astrophysics Data System (ADS)

Zirconium (Zr) thin films deposited on Si (100) by pulsed laser deposition (PLD) at different pulse repetition rates are investigated. The deposited Zr films exhibit a polycrystalline structure, and the X-ray diffraction (XRD) patterns of the films show the ? Zr phase. Due to the morphology variation of the target and the laser—plasma interaction, the deposition rate significantly decreases from 0.0431 Ć/pulse at 2 Hz to 0.0189 Ć/pulse at 20 Hz. The presence of droplets on the surface of the deposited film, which is one of the main disadvantages of the PLD, is observed at various pulse repetition rates. Statistical results show that the dimension and the density of the droplets increase with an increasing pulse repetition rate. We find that the source of droplets is the liquid layer formed under the target surface. The dense nanoparticles covered on the film surface are observed through atomic force microscopy (AFM). The root mean square (RMS) roughness caused by valleys and islands on the film surface initially increases and then decreases with the increasing pulse repetition rate. The results of our investigation will be useful to optimize the synthesis conditions of the Zr films.

Liu, Wei; Wan, Jing-Ping; Cai, Wu-Peng; Liang, Jian-Hua; Zhou, Xiao-Song; Long, Xing-Gui

2014-09-01

391

Electrospun poly (vinyl alcohol)/ alpha-zirconium phosphate nanocomposite fibers  

NASA Astrophysics Data System (ADS)

Poly (vinyl alcohol) (PVA)/alpha-zirconium phosphate (ZrP) polymer nanocomposite (PNC) fibers were successfully prepared via the simple and low-cost electrospinning process. ZrP nanoparticles with two different dimensions, i.e., ZrP-500 with a lateral dimension of ca. 320 nm and an aspect ratio of ca. 500, and ZrP-1500 with a lateral dimension of ca. 950 nm and an aspect ratio of ca. 1500, were utilized to illustrate the size effect on the electrospun nanofibers. In order to obtain defect-free, uniform polymer nanocomposite fibers, a number of parameters including polymer concentration, feed rate, applied voltage and working distance between the needle tip and the fiber collecting substrate were investigated. Scanning electron microscopy (SEM) morphological analysis showed smooth and nonwoven electrospun nanofiber mat. Strong intermolecular interactions between the PVA matrix and the included ZrP nanofillers were revealed by the attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The incorporation of ZrP nanofillers drastically improved the thermal stability of the PNC fibers. TGA results demonstrated a clear thermal stability dependence on the aspect ratio of the crystalline ZrP nanofillers. The degradation temperature was increased by 90 °C for the ZrP-1500 and 60 °C for ZrP-500 when the loading level was increased from 1% to 5%. Furthermore, the viscoelastic properties of the PNC solutions were studied by rheometer.

Lizu, Monira

392

Properties of zirconium carbide for nuclear fuel applications  

NASA Astrophysics Data System (ADS)

Zirconium carbide (ZrC) is a potential coating, oxygen-gettering, or inert matrix material for advanced high temperature reactor fuels. ZrC has demonstrated attractive properties for these fuel applications including excellent resistance against fission product corrosion and fission product retention capabilities. However, fabrication of ZrC results in a range of stable sub-stoichiometric and carbon-rich compositions with or without substantial microstructural inhomogeneity, textural anisotropy, and a phase separation, leading to variations in physical, chemical, thermal, and mechanical properties. The effects of neutron irradiation at elevated temperatures, currently only poorly understood, are believed to be substantially influenced by those compositional and microstructural features further adding complexity to understanding the key ZrC properties. This article provides a survey of properties data for ZrC, as required by the United States Department of Energy's advanced fuel programs in support of the current efforts toward fuel performance modeling and providing guidance for future research on ZrC for fuel applications.

Katoh, Yutai; Vasudevamurthy, Gokul; Nozawa, Takashi; Snead, Lance L.

2013-10-01

393

SURFACE MODIFICATION OF ZIRCALOY-4 SUBSTRATES WITH NICKEL ZIRCONIUM INTERMETALLICS  

SciTech Connect

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.

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

2013-02-01

394

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

SciTech Connect

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.

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

1996-04-01

395

Soil and Sediment Bacteria Capable of Aerobic Nitrate Respiration  

Microsoft Academic Search

Several laboratory strains of gram-negative bacteria are known to be able to respire nitrate in the presence ofoxygen,althoughthephysiologicaladvantagegainedfromthisprocessisnotentirelyclear.Thecontribution that aerobic nitrate respiration makes to the environmental nitrogen cycle has not been studied. As afirst step in addressing this question, a strategy which allows for the isolation of organisms capable of reducing nitrate to nitrite following aerobic growth has been developed.

JON P. CARTER; YA HSIN HSIAO; STEPHEN SPIRO; ANDDAVID J. RICHARDSON

1995-01-01

396

Aerobic nitrate respiration in a nitrite-oxidising bioreactor  

Microsoft Academic Search

The ability of heterotrophic bacteria in a nitrite-oxidising bioreactor to respire with nitrate as an electron acceptor was examined. Approximately 70% of 1000 heterotrophic isolates were able to express a nitrate reductase. A detailed survey of 15 isolates showed that five expressed the azide-insensitive nitrate reductase encoded by the napA gene. A two-round PCR amplification of the napA gene using

Christopher McDevitt; Paul Burrell; Linda L. Blackall; Alastair G. McEwan

2000-01-01

397

Electrochemical cell having an alkali-metal-nitrate electrode  

DOEpatents

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.

Roche, M.F.; Preto, S.K.

1982-06-04

398

Evaluation of nitrate reductase activity in Rhizobium japonicum  

SciTech Connect

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

Streeter, J.G.; DeVine, P.J.

1983-08-01

399

Physiologie vgtale Mesure de l'activit nitrate rductase  

E-print Network

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

Paris-Sud XI, Université de

400

Physiologie vgtale Activit nitrate rductase in vitro de jeunes plantules  

E-print Network

Physiologie végétale Activité nitrate réductase in vitro de jeunes plantules de blé (Triticum faible : 55 ?mol photon.m-2.s-1, «milieu clos», leur activité nitrate réductase est trÚs faible. En absence de ni- trate, il peut s'agir d'une nitrate réductase constitutive, qui varie peu entre 3 et 12 j

Boyer, Edmond

401

Nitrate accelerated corrosion of lead solder in potable water systems  

Microsoft Academic Search

Although nitrate is generally believed to have little effect on lead corrosion, bench-scale tests in this work revealed that increasing nitrate in the range of occurrence in potable water (0–10mg\\/L N) can dramatically increase lead leaching from simulated soldered pipe joints. Lead in water created slightly increased galvanic currents between solder and copper pipe, but nitrate also altered the nature

Caroline K. Nguyen; Kendall R. Stone; Marc A. Edwards

2011-01-01

402

Eutectic composite explosives containing ammonium nitrate  

SciTech Connect

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.

Stinecipher, M.M.

1981-01-01

403

2-Cyano-quinolin-1-ium nitrate.  

PubMed

A proton is transferred from the nitric acid to the N atom of 2-cyano-quinoline during crystallization, resulting in the formation of the title salt, C(10)H(7)N(2) (+)·NO(3) (-). The quinolinium ring system is approximately planar, with a maximum deviation of 0.013?(3)?Ć. In the crystal, a very asymmetric bifurcated N-H?(O,O) hydrogen bond to two O atoms of an adjacent nitrate anion occurs, generating an R(2) (1)(4) ring motif. C-H?O hydrogen bonds link the ions into sheets stacking along the a axis. PMID:21588937

Loh, Wan-Sin; Hemamalini, Madhukar; Fun, Hoong-Kun

2010-01-01

404

Nitration in neurodegeneration: deciphering the "Hows" "nYs".  

PubMed

Recent literature has ushered in a new awareness of the diverse post-translational events that can influence protein folding and function. Among these modifications, protein nitration is thought to play a critical role in the onset and progression of several neurodegenerative diseases. While previously considered a late-stage epiphenomenon, nitration of protein tyrosine residues appears to be an early event in the lesions of amyotrophic lateral sclerosis, Parkinson's disease, and Alzheimer's disease. The advent of highly specific biochemical and immunological detection methods reveals that nitration occurs in vivo with biological selectively and site specificity. In fact, nitration of only a single Tyr residue is often sufficient to induce profound changes in the activity of catalytic proteins and the three-dimensional conformation of structural proteins. Presumably, nitration modifies protein function by altering the hydrophobicity, hydrogen bonding, and electrostatic properties within the targeted protein. Most importantly, however, nitrative injury may represent a unifying mechanism that explains how genetic and environmental causes of neurological disease manifest a singular phenotype. In this review and synthesis, we first examine the pathways of protein nitration in biological systems and the factors that influence site-directed nitration. Subsequently, we turn our attention to the structural implications of site-specific nitration and how it affects the function of several neurodegeneration-related proteins. These proteins include Mn superoxide dismutase and neurofilament light subunit in amyotrophic lateral sclerosis, alpha-synuclein and tyrosine hydroxylase in Parkinson's disease, and tau in Alzheimer's disease. PMID:17542619

Reynolds, Matthew R; Berry, Robert W; Binder, Lester I

2007-06-26

405

Who is drinking nitrate in their well water?  

SciTech Connect

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.

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

1996-10-01

406

Nitrate Leaching from Intensive Fiber Production on Abandoned Agricultural Land  

SciTech Connect

Paper outlines nitrate leaching results of loblolly pine and sweet gum that were grown with irrigation, continuous fertilization and insect pest control on a year old abandoned peanut field. Wells and tension lysimeters were used to measure nitrate in soil moisture and groundwater on three replicate transects for two years. Groundwater nitrate concentration beneath the minimum treatment was much higher than the maximum treatment and old field. All three treatments often exceeded the drinking water standard. Forest and lake edge had low levels while the soil moisture nitrate concentrations in the two plantation treatments were much higher than the old field.

Williams, T.M.

1999-01-01

407

Synthesis of Aliphatic Nitrate Esters by Reaction of Metal Nitrates with Phosphate Esters.  

National Technical Information Service (NTIS)

A safe and simple method of synthesizing short-chain alkyl nitrates is described. This method, which should be of general utility, was found to be useful in preparing compounds for studies to determine the fate of organic materials in nuclear fuel reproce...

W. B. Howerton, W. E. Clark, W. H. Baldwin

1979-01-01

408

Utility of anhydrous neodymium nitrate as a precursor to extended organoneodymium nitrate networks.  

PubMed

Hydrated neodymium nitrates can be readily transformed to anhydrous ether solvates which react with cyclopentadienyl reagents to make organometallic nitrate complexes with variable degrees of oligomerization. Heating Nd(NO(3))(3)(H(2)O)(6) in tetrahydrofuran at reflux, removal of solvent, drying at 100 degrees C under high vacuum, and addition of hot THF generates Nd(NO(3))(3)(THF)(3), 1. Using dimethoxyethane, Nd(NO(3))(3)(DME)(2), 2, can be obtained similarly. Addition of NaC(5)Me(5) to 1 generates (C(5)Me(5))Nd(NO(3))(3)(THF)Na(THF)(x)complexes which crystallize as ([(C(5)Me(5))(NO(3))(2)Nd(THF)(micro-NO(3))](2)Na(THF)(4))[Na(THF)(6)], 3, or [(C(5)Me(5))Nd(THF)(mu-NO(3))(3)Na(THF)(2)](n), 4, depending on the conditions. The trimetallic Nd(2)Na unit in 3 forms an extended system in 4 via bridging nitrates. Addition of KC(5)Me(5) and 18-crown-6 to 1 generates another extended complex [(C(5)Me(5))Nd(THF)(NO(3))(mu-NO(3))(2)K(18-crown-6)](n), 5, in which an 18-crown-6 ligated potassium links neodymium centers via two bridging nitrates and an agostic interaction between a C(5)Me(5) methyl group and potassium. PMID:15332828

Evans, William J; Giarikos, Dimitrios G; Workman, Penny S; Ziller, Joseph W

2004-09-01

409

EXAFS studies of structural changes in fragile glasses of zinc nitrate and nickel nitrate hydrates.  

PubMed

The ionic structures of aqueous solutions of two sets of transition metal nitrates have been studied in the liquid and glass states by EXAFS spectroscopy. Experiments were carried out on Zn(NO3)2.xH2O, with x=2, 6, 12 and NiNO.9HO over the temperature range 30nitrate hydrates show complex behaviour depending on the concentration. This behaviour is explained in terms of first hydration shell stability and NO3- penetration. This result contrasts with that for the equivalent correlation in nickel nitrate, and is taken as evidence for a more extensive free energy landscape of zinc nitrate hydrates. The results are also consistent with the known hydration properties of Zn2+ and Ni2+, and help explain why Zn2+ is biologically active in solution. PMID:14967238

Ansell, S; Neilson, G W

2004-02-15

410

Nitrate rich and nitrate poor water masses in the equatorial Pacific  

E-print Network

circulation model (Maes et al., 1997; Vialard et al.,2001) tropical Pacific 30°S-30°N x = 1° y = from 03 poor waters from the warm pool and the north-west tropical Pacific spread eastward · nitrate

411

Developmental stage-specific and nitrate-independent regulation of nitrate reductase gene expression in rapeseed.  

PubMed Central

cDNA clones for two isogenes of nitrate reductase (NR) have been isolated from rapeseed (Brassica napus L.) androgenetic haploid embryos induced by microspore culture. NR mRNA accumulation can be detected by northern hybridization at 14 d after culture initiation when embryos develop to the heart/torpedo-shaped stage. Whole-mount in situ hybridization experiments demonstrate that the mRNA accumulation is developmental stage specific. In addition, even when cultured in media containing no nitrate, embryos accumulated NR mRNA to almost the same level as the control. This indicates the unique regulation of NR in embryogenesis in which NR mRNA transcription is activated in a developmental stage-specific manner that is independent of nitrate induction. In zygotic embryogenesis, a stage-specific accumulation of NR mRNA was also observed. By contrast, the obvious effect of nitrate on NR expression that has been reported in many plant species was also confirmed in rapeseed leaf. Quantitative combined reverse transcription-polymerase chain reaction analysis suggests that the flexible and variable regulation of NR expression, which is organ specific, nitrogen metabolite specific, and developmental stage specific, is caused principally by regulation of one major structural gene. PMID:8685274

Fukuoka, H; Ogawa, T; Minami, H; Yano, H; Ohkawa, Y

1996-01-01

412

[Effect of nitrate and cytokinin on nitrate reductase activity in isolated corncockle embryos].  

PubMed

The effects of cytokinin and nitrate on the activity of nitrate reductase (NR) in isolated embryos of Agrostemma githago L. were studied. It was shown that the effects of cytokinin and NO-3 on the induction of NR is additive during 8, 12 and 18 hrs of embryos incubation in the solutions of the two inducers. Anticytokinin decreased the cytokinin induced NR by 35--39% and had no effect on the NR induction by nitrate. The substrate and hormonal induction of NR differed in the duration of the lag period. This difference dependent on the physiological state of the embryos at the beginning of incubation. The data obtained are indicative of the independence of cytokinin and NO-3 effects on the NR synthesis in isolated embryos of Agrostemma githago L. Abscisic acid supressed cytokinin- and nitrate-induced NR and had practically no effect on total incorporation of the label into the protein. It is assumed that the induced synthesis of the protein is more sensitive to the action of abscisic acid that the total protein synthesis. PMID:155476

Kuznetsov, V V; Kuznetsov, V V; Kulaeva, O N

1979-04-01

413

High temperature oxidation of zirconium and zircaloy-4 under applied load: Nuclear microprobe study of the growth of the oxide  

Microsoft Academic Search

The understanding of the mechanisms of high temperature growth of zirconium oxide on zircaloy alloys is of considerable importance owing to the world-wide use of zirconium in nuclear plants. Spallations and growth recovery are known to originate in structural changes of the oxide, but the induced modifications in the oxygen transport have still to be investigated. The zirconia is known

P. Berger; R. El Tahhann; G. Moulin; M. Viennot

2003-01-01

414

Wycheproofite: A New Hydrated Sodium Aluminium Zirconium Phosphate from Wycheproof, Victoria, Australia, and a New Occurrence Of Kosnarite  

Microsoft Academic Search

Wycheproofite is a new hydrated sodium aluminium zirconium phosphate from a pegmatite vein in granite at Wycheproof, in northwestern Victoria, Australia. The mineral occurs as compact, finely fibrous masses in small cavities in the quartzjfeldsparjmuscovitejschorl-bearing pegmatite. The fibrous crystals are between 5 and 10 11mwide and up to several rom long. Accompanying minerals include two other zirconium phosphates - kosnarite

William D. Birch; ALLAN PRING; D. J. M. BEVAN

1994-01-01

415

Chemical Behaviour of Zirconium Oxychloride Octahydrate and Acetic Acid in Precursor Solution for Zirconia Film Formation on Glass  

Microsoft Academic Search

Precursor solutions for zirconia films on soda lime silica glass substrate were prepared from zirconium oxychloride octahydrate (ZOO) and acetic acid (HOAC) maintaining the mol ratios, [HOAC]\\/[ZOO] = 2, 4, 6, 8 and 10. A characteristic UV absorption band at ~280 nm in the ~120 h aged precursor solutions was identified for acetate group of the zirconium acetato complexed species.

Sunirmal Jana; K. Biswas

1997-01-01

416

THE JOURNAL OF CHEMICAL PHYSICS 135, 104303 (2011) The visible spectrum of zirconium dioxide, ZrO2  

E-print Network

THE JOURNAL OF CHEMICAL PHYSICS 135, 104303 (2011) The visible spectrum of zirconium dioxide, ZrO2; published online 8 September 2011) The electronic spectrum of a cold molecular beam of zirconium dioxide, Zr to difficulties of generation and detection of these ephemeral molecules. The dioxides can have one of three

Maier, John Paul

417

Preparation of nitramine-nitrates by ring-opening nitration of azetidines by dinitrogen pentoxide (N 2O 5)  

Microsoft Academic Search

Eleven azetidines, bearing various types of substituents on the ring nitrogen, were treated with N2O5 in chlorinated solvents at sub-ambient temperature and in certain cases formed 1,3-nitramine-nitrate products by a novel ring-opening nitration reaction analogous to that established for aziridines. Yields of the nitramine-nitrates, where ring-opening took place, were generally moderate to high (41–88%), but azetidines bearing N-acyl substituents (acetyl,

Peter Golding; Ross W. Millar; Norman C. Paul; David H. Richards

1995-01-01

418

The development of nitrate reductase in Chlorella and its repression by ammonium  

Microsoft Academic Search

Chlorella vulgaris, grown with ammonium sulphate as nitrogen source, contains very little nitrate reductase activity in contrast to cells grown with potassium nitrate. When ammonium-grown cells are transferred to a nitrate medium, nitrate reductase activity increases rapidly and the increase is partially prevented by chloramphenicol and by p-fluorophenylalanine, suggesting that protein synthesis is involved. The increase in nitrate reductase activity

I. Morris; P. J. Syrett

1963-01-01

419

Isotopes for improved management of nitrate pollution in aqueous resources: review of surface water field studies  

Microsoft Academic Search

For water bodies where the nitrate concentrations exceed threshold values environmental agencies can propose measures to either reduce discharges and emissions of nitrate or to remediate nitrate polluted water bodies. Isotope data can support the identification of nitrate pollution sources and natural attenuation processes of nitrate. A review of surface water field studies evaluated the use of isotope data (e.g.

A. Nestler; M. Berglund; F. Accoe; S. Duta; D. Xue; P. F. Boeckx; P. Taylor

2010-01-01

420

Electrochemical processing of nitrate waste solutions  

SciTech Connect

Nitrate and nitrite have been almost completely removed from the synthetic effluent steam with good efficiency by affecting a separation across a pair of ion exchange membranes. In addition to recovering acid and base in this process, the volume of the remaining effluent is reduced considerably by transport of water across the membrane. One of the problems that remains with this process, however, is the stability of the membranes and particularly the stability of the anion exchange membrane. This membrane is exposed to both nitric acid and strongly alkaline solutions in the cell and to date long term stability has been a problem with the membranes tested. It is recommended that further work should evaluate other newly available membranes as well as study the effects of radiation on the performance of the membranes. The direct reduction of nitrate and nitrite has been studied at several different electrode materials and it has been demonstrated that cathode material has a large effect on both the efficiency and the gas product distribution. Highest current efficiencies for the reduction process are seen at those electrode materials that are known to show high hydrogen overpotentials. Flow cell studies have demonstrated that temperature and current density are also important parameters in the system. The reduction process has been run efficiently at high current densities (600 mAcm{sup {minus}2}) at 80{degrees}C at a lead cathode.

Not Available

1990-10-12

421

Hydrogen Embrittlement in Zirconium: a Quasi-Continuum Density Functional Theory Study  

NASA Astrophysics Data System (ADS)

The hydrogen embrittlement in Zirconium becomes a very important and emergent issue for academia, industry and policy makers as a result of the Japan nuclear accident. The hydride formation, diffusion and embrittlement in zircolay will impact dramatically on the development of advanced nuclear energy systems, the life time extension of the current nuclear fleet and dry storage of spent nuclear fuel. Quasi-Continuum Density Functional Theory (QCDFT) is a powerful concurrent multiscale method based entirely on density functional theory (DFT) and allows quantum simulations of materials properties of a large system with billions of atoms. Using QCDFT modeling, we found that the presents of hydrogen at the cracktip of zirconium, both on crack surface and in-bulk, will form zirconium hydrides and embrittle the system. The concentration of hydrogen and orientation of crack plays important roles in such embrittlement. The mechanism of hydrogen embrittlement under various loading conditions will be discussed.

Peng, Q.

2012-02-01

422

Theoretical study of the reaction between 2,2???,4???-trihydroxyazobenzene-5-sulfonic acid and zirconium  

USGS Publications Warehouse

Zirconium reacts with 2,2???,4???-trihydroxyazobenzene-5-sulfonic acid in acid solutions to Form two complexes in which the ratios of dye to zirconium are 1 to 1 and 2 to 1. Both complexes are true chelates, with zirconium acting as a bridge between the two orthohydroxy dye groups. Apparent equilibrium constants for the reactions to form each of the complexes are determined. The reactions are used as a basis for the determination of the active component in the dye and a graphical method for the determination of reagent purity is described. Four absorption spectra covering the wave length region from 350 to 750 m?? are given, which completely define the color system associated with the reactions in solutions where the hydrochloric acid concentration ranges from 0.0064N to about 7N.

Fletcher, M.H.

1960-01-01

423

Porous desulfurization sorbent pellets containing a reactive metal oxide and an inert zirconium compound  

SciTech Connect

Sorbent pellets for removing hydrogen sulfide from coal gas are prepared by combining a reactive oxide, in particular zinc oxide, with a zirconium compound such as an oxide, silicate, or aluminate of zirconium, and an inorganic binder and pelletizing and calcining the mixture. Alternately, the zinc oxide may be replaced by copper oxide or a combination of copper, molybdenum, and manganese oxides. The pellet components may be mixed in dry form, moistened to produce a paste, and converted to pellets by forming an aqueous slurry of the components and spray drying the slurry, or the reactive oxide may be formed on existing zirconium-containing catalyst-carrier pellets by infusing a solution of a salt of the active metal onto the existing pellets and firing at a high temperature to produce the oxide. Pellets made according to this invention show a high reactivity with hydrogen sulfide and durability such as to be useful over repeated cycles of sorption and regeneration.

Gardner, Todd H.; Gasper-Galvin, Lee D.

1996-12-01

424

A novel zirconium K{alpha} imager for high energy density physics research  

SciTech Connect

We report on the development and characterization of a zirconium K{alpha} imager for high energy density physics research. The imager consists of a spherically bent quartz crystal operating at 15.7 keV photon energy. We compare the performance of the imager in terms of integrated reflectivity (R{sub int}) and temperature dependent collection efficiency ({eta}{sub Te}) to that of the widely used Cu K{alpha} imager. Our collisional-radiative simulations show that the new imager can be reliably used up to 250 eV plasma temperature. Monte Carlo simulations show that for a 25 {mu}m thick tracer layer of zirconium, the contribution to K{alpha} production from photo-pumping is only 2%. We present, for the first time, 2D spatially resolved images of zirconium plasmas generated by a high intensity short pulse laser interacting with Zr solid targets.

Akli, K. U.; Jiang, S.; Storm, M. S.; Krygier, A.; Freeman, R. R. [The Ohio State University, Columbus, Ohio 43210 (United States); Sanchez del Rio, M. [European Synchrotron Radiation Facility (France); Stephens, R. B. [General Atomics, San Diego, California 92121 (United States); Pereira, N. R. [Ecopulse Inc., Springfield, Virginia 22152 (United States); Baronova, E. O. [RRC Kurchatov Institute, Moscow (Russian Federation); Theobald, W. [Laboratory for Laser Energetics, Rochester, New York 14623 (United States); Ping, Y.; McLean, H. S.; Patel, P. K.; Key, M. H. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2011-12-15

425

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

USGS Publications Warehouse

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

Lamar, W.L.

1945-01-01

426

Influence de la teneur en nitrate sur l'volution des activits nitrate rductase et nitrognase du  

E-print Network

Influence de la teneur en nitrate sur l'évolution des activités nitrate réductase et nitrogénase du'évolution des activités nitrate réductase et nitrogénase (réduction de l'acétylÚne) a été suivie au cours du cycle du fenugrec (Trigonella foenum-graecum L.) cultivé en plein champ avec et sans apport de nitrate

Paris-Sud XI, Université de

427

Bayesian model selection validates a biokinetic model for zirconium processing in humans  

PubMed Central

Background In radiation protection, biokinetic models for zirconium processing are of crucial importance in dose estimation and further risk analysis for humans exposed to this radioactive substance. They provide limiting values of detrimental effects and build the basis for applications in internal dosimetry, the prediction for radioactive zirconium retention in various organs as well as retrospective dosimetry. Multi-compartmental models are the tool of choice for simulating the processing of zirconium. Although easily interpretable, determining the exact compartment structure and interaction mechanisms is generally daunting. In the context of observing the dynamics of multiple compartments, Bayesian methods provide efficient tools for model inference and selection. Results We are the first to apply a Markov chain Monte Carlo approach to compute Bayes factors for the evaluation of two competing models for zirconium processing in the human body after ingestion. Based on in vivo measurements of human plasma and urine levels we were able to show that a recently published model is superior to the standard model of the International Commission on Radiological Protection. The Bayes factors were estimated by means of the numerically stable thermodynamic integration in combination with a recently developed copula-based Metropolis-Hastings sampler. Conclusions In contrast to the standard model the novel model predicts lower accretion of zirconium in bones. This results in lower levels of noxious doses for exposed individuals. Moreover, the Bayesian approach allows for retrospective dose assessment, including credible intervals for the initially ingested zirconium, in a significantly more reliable fashion than previously possible. All methods presented here are readily applicable to many modeling tasks in systems biology. PMID:22863152

2012-01-01

428

Laboratory and Clinical Performance of Oxidized Zirconium Alloy  

PubMed Central

Introduction: More demanding performance expectations in total joint arthroplasty are driving the development of alternative bearing materials. The original and still most popular choice for an articulating couple is a metal cobalt-chromium alloy (CoCr) articulating against ultra-high molecular weight polyethylene (UHMWPE). Attempts have been made to harden the CoCr surface to resist roughening and reduce friction in order to reduce the wear of the UHMWPE counterface. Unfortunately, the durability of the hardened CoCr surfaces has been less than desired. By the early 1990s, the use of alumina and zirconia ceramics as a replacement for the metal counterface in hip arthroplasty was shown to reduce polyethylene wear. However, the usage of ceramic components remains limited by the lower toughness of the material, particularly in the complex geometries typical of knee arthroplasty components. In 1997, a metallic zirconium alloy (Zr-2.5Nb) with a ceramic surface was introduced as an alternative to CoCr for the knee femoral component. Through a thermally-driven oxidation process, oxygen diffuses into the surface of the metal and transforms it to monoclinic zirconia to a depth of approximately 5 microns. This oxidized zirconium (OxZr) product offers the benefit of an articulating ceramic surface with the toughness of metal. The goal of this abstract is to compare the mechanical performance of OxZr to conventional orthopaedic materials with respect to mechanical and clinical performances. Mechanical performance: The surface hardness of OxZr and CoCr was measured with a nano-indentation method, indicating that the OxZr surface is over two times harder than that of the CoCr. The harder surface resists roughening and also is very durable. These characteristics were demonstrated in abrasion testing against bone cement pins where OxZr produced 4900 times less volumetric wear and 160 times less roughness after 10 million cycles of articulation. The coefficient of friction against UHMWPE for OxZr is nearly half that of CoCr. Contributing to this behavior is the improved wetting behavior of fluids on OxZr surfaces compared to CoCr surfaces. These positive attributes of OxZr are shown in the Figure 1. Because of OxZr’s improved resistance to abrasion, low friction and high wettability, the wear of UHMWPE was demonstrated to be 40 to 90% less in numerous hip and knee wear simulator tests. In addition, mechanical testing demonstrates that OxZr components do not exhibit brittle fracture and knee femoral components have equivalent device fatigue strength to CoCr components of the same size and design. The alloy contains two of the most biocompatable elements (Zr and Nb) – OxZr components have undetactable amount of nickel – and therefore offers an attractive option for metal sensitive patients. Clinical performance: Since the first OxZr total knee arthroplasty surgery in late 1997, over 225,000 femoral components have been implanted. This is in addition to over 110,000 OxZr hip replacements. Several clinical studies have shown that the patient performance is at least equivalent to that of CoCr patients at short and medium-term follow up. A much longer time period will be required to measure differences in UHMWPE wear and implant survivorship. Conclusions: The advantage of the OxZr material over conventional orthopaedic materials was highlighted in these laboratory studies. In clinical usage, OxZr is expected to provide the wear benefits of a monolithic ceramic without the associated mechanical limitations.

Salehi, A.; Hunter, G.

2010-01-01

429

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

SciTech Connect

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

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

2004-03-01

430

Growth of Zirconium Silicate Thin Film by Pulsed-Mocvd Using Ztb and Tdeas  

NASA Astrophysics Data System (ADS)

Zirconium silicate (ZrxSi1-xO2) thin films were deposited by pulsed metal-organic chemical vapor deposition (MOCVD) using zirconium tert-butoxide (ZTB) and tetrakis-diethylamido silane (TDEAS). The growth temperature of 200-300°C was used to deposit films with uniform thickness. The grown films showed the Zr-rich composition, which is thought to induce the Zr-silicide formation at the interface of the silicate and Si substrate. The film composition and chemical binding states were investigated by XPS depth profiling measurements.

Kim, Jaehyun; Yong, Kijung

431

Stainless steel-zirconium waste forms from electrometallurgical treatment of spent nuclear fuel.  

SciTech Connect

Stainless steel-zirconium waste-form alloys have been developed for the disposal of metallic wastes recovered from spent nuclear fuel using the electrometallurgical process developed by Argonne National Laboratory. The metal waste comprises the spent-fuel cladding, noble-metal fission products, and other metallic constituents remaining after electrorefining. Two nominal waste-form compositions have been selected: stainless steel-clad fuels and zirconium-8 wt.% stainless steel for Zircaloy-clad fuels. These alloys are very corrosion resistant. Tests performed with these alloys indicate favorable behavior for use high-level nuclear waste forms.

McDeavitt, S. M.; Abraham, D. P.; Park, J. Y.; Keiser, D. D., Jr.; Chemical Engineering

1997-01-01

432

Rubidium and Zirconium Production in Massive AGB Stars  

SciTech Connect

A recent survey of a large sample of massive Galactic asymptotic giant branch (AGB) stars shows that significant overabundances of rubidium (up to 100 times solar), but merely solar zirconium, are present in these stars. These observations can set constraints on our theoretical notion of the slow neutron capture process (the s process) in AGB stars, as well as on the rates of the neutron capture reactions involved in the production of Rb and Zr. We use the Monash nucleosynthesis code with a recently extended network to try to reproduce these observations. We present results for AGB stars of masses 5, 6, and 6.5 M{center_dot} and solar metallicity. We also show results for different available choices of the neutron capture rates, as well as for the possible inclusion of a partial mixing zone (PMZ), leading to the activation of the {sup 13}C neutron source. We find increasing Rb overabundances with increasing stellar mass, as observed, but we are far from matching the highest observed Rb enhancements. Inclusion of a PMZ increases the Rb abundance, but also produces an overabundance of Zr, contrary to what is observed. Only if the third dredge up efficiency remains as high as before the onset of the superwind phase during the final few pulses of a massive AGB star, can we match the highest [Rb/Fe] ratios observed by Garcia-Hernandez et al. [l]. A better understanding of the third dredge up efficiency with decreasing envelope mass for massive AGB stars is essential for further investigation of this issue.

Raai, M. A. van; Lugaro, M. [Sterrekundig Instituut, University of Utrecht, Postbus 80000, 3508 TA Utrecht (Netherlands); Karakas, A. I. [Research School of Astronomy and Astrophysics, Mt. Stromlo Observatory, Cotter Rd., Weston, ACT (Australia); Garcia-Hernandez, D. A. [lnstituto de Astrofisica de Canarias, La Laguna (Tenerife) (Spain)

2008-04-06

433

ISO-OSMOTIC REGULATION OF NITRATE ACCUMULATION IN LETTUCE  

Microsoft Academic Search

Concerns about possible health hazards arising from human consumption of lettuce and other edible vegetable crops with high concentrations of nitrate have generated demands for a greater understanding of processes involved in its uptake and accumulation in order to devise more sustainable strategies for its control. This paper evaluates a proposed iso-osmotic mechanism for the regulation of nitrate accumulation in

Ian G. Burns; Kefeng Zhang; Mary K. Turner; Rodney Edmondson

2010-01-01

434

Removal of nitrate and fluoride by nanofiltration – a comparative study  

Microsoft Academic Search

High levels of nitrate and fluoride are causing a major threat to drinking water production in many countries worldwide. Besides reverse osmosis, recent publications indicate that nanofiltration (NF) is a promising technology to remove nitrate and fluoride from surface and groundwater. However, the tightness of the NF membranes plays a major role in the removal efficiency. Within this work, therefore,

Jan Hoinkis; Sara Valero-Freitag; Martin P. Caporgno; Christian Pätzold

2011-01-01

435

Geospatial approach to Nitrate-leaching index for Virginia  

Microsoft Academic Search

Excess nitrate-N leaching into ground and surface waters from agricultural regions has been an increasing concern throughout the U.S. Currently, the nitrate-leaching index (LI) in Virginia is assigned by county based on tables that were \\

Patricia Donovan; W. L. Daniels

436

Nitrate Behavior in Ground Waters of the Southeastern United States  

Microsoft Academic Search

Principal components analysis (PCA) was performed with water-quality data from studies conducted during 1993-1995 to explore potential nitrate-attenuation processes in ground waters of the southeastern United States. Nitrate reduction is an important attenuation process in selected areas of the Southeast. A \\

Bernard T. Nolan

437

Cu(II) - Catalyzed Hydrazine Reduction of Ferrous Nitrate  

SciTech Connect

This report discusses the results of a study of catalyzed hydrazine reduction of ferrous nitrate. It is apparent that there is a substantial reaction between hydrazine and nitrate ion (or nitric acid) to produce HN3 during both the reduction of Fe(III) and during storage at room temperature.

Karraker, D.G.

2001-10-15

438

Effect of Gallium Nitrate on Experimental Autoimmune Uveitis  

Microsoft Academic Search

Gallium nitrate (GN) has been shown to inhibit T cell-mediated inflammatory disease. The purpose of our study was to test the effect of gallium nitrate (GN) on experimental autoimmune uveitis (EAU). Experimental autoimmune uveitis was induced in male Lewis rats immunized with retinal S-antigen. Rats received subcutaneous injections of GN or saline one day prior to immunization and 1, 4,

MARK C. LOBANOFF; ALEXANDER T. KOZHICH; DANIEL I. MULLET; NICHOLAS GERBER; IGAL GERY; CHI-CHAO CHAN; SCOTT M. WHITCUP

1997-01-01

439

ISUS\\/SUNA nitrate measurements in networked ocean observing systems  

Microsoft Academic Search

Sustaining measurements of water quality parameters in sensitive watershed habitats is challenging, particularly during critical periods such as spring blooms, and major run off events. Direct, in situ measurements of nitrate have been difficult to obtain until the development of the ISUS (In Situ Ultraviolet Spectrometer, Johnson & Coletti 2002) and more recently the next generation SUNA (Submersible Ultraviolet Nitrate

G. MacIntyre; B. Plache; M. R. Lewis; J. Andrea; S. Feener; S. D. McLean; K. S. Johnson; L. J. Coletti; H. W. Jannasch

2009-01-01

440

NITRATE REMOVAL FROM WATER SUPPLIES BY ION EXCHANGE - EXECUTIVE SUMMARY  

EPA Science Inventory

Anion exchange using synthetic organic resins is a proven and practical technology for the removal of nitrate from water supplies. However, disposal of the spent regenerant brime solution containing nitrate is a potential problem. Two processes were examined in detail in this rep...

441

NITRATE REMOVAL FROM WATER SUPPLIES BY ION EXCHANGE  

EPA Science Inventory

Anion exchange using synthetic organic resins is a proven and practical technology for the removal of nitrate from water supplies. However, disposal of the spent regenerant brine solution containing nitrate is a potential problem. Two processes were examined in detail in this rep...

442

Potential Radon222 Emissions from the Thorium Nitrate Stockpile  

Microsoft Academic Search

The Defense National Stockpile Center (DNSC), a field level activity of the Defense Logistics Agency, has stewardship of a stockpile of thorium nitrate that has been in storage for decades. The thorium nitrate stockpile was produced from 1959 to 1964 for the Atomic Energy Commission and previously has been under the control of several federal agencies. The stockpile consists of

2003-01-01

443

REMEDIATION OF NITRATE-CONTAMINATED GROUNDWATER USING A BIOBARRIER  

Microsoft Academic Search

A biobarrier system has been developed for use in remediating shallow alluvial groundwater. This barrier is made from highly porous materials that are relatively long-lasting, carbon-based (to supply a limiting nutrient in nitrate destruction, in most cases), extremely inexpensive, and easy to replace. In a series of laboratory studies, we have determined the effectiveness of this barrier at destroying nitrate

B. A. Strietelmeier; M. L. Espinosa

2001-01-01

444

Copper-catalyzed mild nitration of protected anilines.  

PubMed

A practical copper-catalyzed direct nitration of protected anilines, by using one equivalent of nitric acid as the nitrating agent, has been developed. This procedure features mild reaction conditions, wide structural scope (with regard to both N-protecting group and arene substitution), and high functional-group tolerance. Dinitration with two equivalents of nitric acid is also feasible. PMID:25213167

Hernando, Elier; Castillo, Rafael R; Rodríguez, Nuria; Gómez Arrayás, Ramón; Carretero, Juan C

2014-10-20

445

Predicting ground water nitrate concentration from land use  

Microsoft Academic Search

Ground water nitrate concentrations on Nantucket Island, Massachusetts, were analyzed to assess the effects of land use on ground water quality. Exploratory data analysis was applied to historic ground water nitrate con- centrations to determine spatial and temporal trends. Maximum likelihood Tobit and logistic regression analyses of explanatory variables that characterize land use within a 1000-foot radius of each well

Kristin K. Gardner; Richard M. Vogel

2005-01-01

446

Evaluation of nitrate and nitrite destruction/separation technologies  

SciTech Connect

This report describes and evaluates four types of nitrate and nitrite destruction and separation technologies that could be used to treat the aqueous, alkaline, nitrate-bearing mixed waste that is generated by the In-Tank Precipitation (ITP) process at the Savannah River Site (SRS). The technologies considered in this report include thermal, hydrothermal, chemical, and electrochemical technologies.

Hobbs, D.T.

1997-08-29

447

Hydrodynamic characteristics and nitrate propagation in Sparta aquifer  

Microsoft Academic Search

During the 1994–1997 water years, a hydrogeological study was carried out on the alluvial aquifer of Sparta in the Peloponnese, where the concentration of nitrate ions in groundwater, as NO?3, is well over the highest recommended WHO limits of 50 mg l?. Under specific hydrological and chemical conditions with high amounts of dissolved oxygen, the migration of nitrate ions in the

Andreas Antonakos; Nicolaos Lambrakis

2000-01-01

448

Nitrate formation in acid forest soils from the Adirondacks  

SciTech Connect

Nitrate formation in three forest soils from the Adirondacks region of New York was studied in the laboratory. The organic and surface mineral layers of the soils has pH values ranging from 3.6 to 4.1. Nitrate was formed when the soils were treated with artificial rain at pH 3.5, 4.1, or 5.6. Compared to simulated rain at pH 5.6, simulated rain at pH 3.5 enhanced nitrate formation in one soil and inhibited it in two other soils. The rate of nitrate accumulation was about 10 times higher in the organic horizon than in the mineral horizon, and nitrate formation was not enhanced by ammonium additions. Nitrate formation in soil suspensions was dependent on the amount of soil in the suspension, and none was formed if little soil was present. Ammonium did not enhance nitrate production in the suspensions. It is suggested that nitrate formation in these acid soils is not limited by the ammonium supply. 19 references, 2 figures, 2 tables.

Klein, T.M.; Kreitinger, J.P.; Alexander, M.

1983-01-01

449

Method for improved decomposition of metal nitrate solutions  

DOEpatents

A method for co-conversion of aqueous solutions of one or more heavy metal nitrates wherein thermal decomposition within a temperature range of about 300.degree. to 800.degree. C. is carried out in the presence of about 50 to 500% molar concentration of ammonium nitrate to total metal.

Haas, Paul A. (Knoxville, TN); Stines, William B. (Knoxville, TN)

1983-10-11

450

Method for improved decomposition of metal nitrate solutions  

DOEpatents

A method for co-conversion of aqueous solutions of one or more heavy metal nitrates is described, wherein thermal decomposition within a temperature range of about 300 to 800/sup 0/C is carried out in the presence of about 50 to 500% molar concentration of ammonium nitrate to total metal.

Haas, P.A.; Stines, W.B.

1981-01-21

451

Nitrate Water Activities, Science Study Aid No. 4.  

ERIC Educational Resources Information Center

Intended to supplement a regular program, this pamphlet provides background information, related activities, and suggestions for other activities on the subject of nitrate as a water pollutant. Two activities related to plant nutrient pollution, nitrate filtration and measuring mitrate used by plants, are explained in detail, outlining objectives,…

Agricultural Research Service (USDA), Washington, DC.

452

Glucose-mediated tyrosine nitration in adipocytes: Targets and consequences  

Microsoft Academic Search

Hyperglycemia, a key factor in insulin resistance and diabetic pathology, is associated with cellular oxidative stress that promotes oxidative protein modifications. We report that protein nitration is responsive to changes in glucose concentrations in 3T3-L1 adipocytes. Alterations in the extent of tyrosine nitration as well as the cellular nitroproteome profile correlated tightly with changing glucose concentrations. The target proteins we

Thomas Koeck; Belinda Willard; John W. Crabb; Mike Kinter; Dennis J. Stuehr; Kulwant S. Aulak

2009-01-01

453

Phytoremediation of Nitrate-Contaminated Groundwater by Desert Phreatophytes  

Microsoft Academic Search

Two native halophytic shrubs were evaluated for phytoremediation of a nitrate- contaminated aquifer at a former uranium mill site. The shrubs, Sarcobatus vermiculatus and Atriplex canescens, obligate and facultative phreatophytes, respectively, dominate the desert plant community. Stable isotope signatures suggested that both species are rooted into the nitrate plume, a depth averaging more than 10 meters. Aerial photography and ground

Casey McKeon; Edward P. Glenn; David Moore; W. Jody Waugh

454

FORMATION AND FATE OF ATMOSPHERIC NITRATES: WORKSHOP PROCEEDINGS  

EPA Science Inventory

Articles based on formal presentations given October 22-23, 1979, at the 'Workshop on the Formation and Fate of Atmospheric Nitrates' are documented in the report. The authors discuss nitrate formation from both theoretical (gas and aerosol formation models) and applied (smog cha...

455

Removal of nitrate from JUST wastewater effluent: a case study  

Microsoft Academic Search

Eutrophication phenomena occurred at JUST constructed pond. The main reason of this eutrophication process is the wastewater effluent of the campus wastewater treatment plant. This is due high nitrate content of the water effluent. The objective of this project is to decrease the concentration of nitrate in the wastewater effluent of the campus wastewater treatment plant in an attempt to

S. Al-Asheh; A. Al-Zoubi; H. Malas

2012-01-01

456

Nitrate-Cancrinite Precipitation on Quartz Sand in Simulated Hanford  

E-print Network

Nitrate-Cancrinite Precipitation on Quartz Sand in Simulated Hanford Tank Solutions B A R R Y R . B minerals at the U.S. Department of Energy's Hanford site in Washington. Nitrate-cancrinite began's (DOE) Hanford Site in southeast Washington since the late 1950s (1). To predict the fate

Illinois at Chicago, University of

457

Is the measurement of the isotopic composition of nitrate a good tool for tracing sources of nitrate in groundwater?  

NASA Astrophysics Data System (ADS)

Isotopic biogeochemistry allows tracing of nitrogen sources in the environment. The dual approach i.e 15N and 18O approach has been used for decades to determine the origin of nitrate in surface and groundwater. The isotopic composition of fertilizers differs for example significantly from that of nitrate in atmospheric deposition and nitrate produced by nitrification. A long term study (30 years) based on the use of lysimeters and 15N labelled nitrate showed that nitrate which is not immediately taken up by plants is assimilated into the organic matter pool. This pool produces nitrate, with an isotopic signature of 'newly produced nitrate' and different from its origin (1). Based on this study, the natural stable isotopic composition of nitrate (?18O-NO3-and?15N-NO3-)was measured in water samples collected below the root zone or in aquifers from the Seine River basin. We compared these with the isotopic composition of nitrate from synthetic fertilizers and atmospheric deposition which represent the most significant sources of nitrogen in these systems. In addition, the ?15N of the organic matter pool in cultivated soils from this area was analyzed. The ?18O-NO3-results show clearly that nitrate issued from highly fertilized agricultural soils are freshly produced through nitrification of reduced nitrogen in the soil, instead of being directly transferred through the soil profile from applied fertilizers, indicating the major role of the soil organic matter pool. Our results thus bring new insights in the understanding of nitrogen contamination of surface and groundwater from agricultural watersheds, emphasizing the role of soil organic matter as a buffer. (1). Sebilo M., Nicolardot B., Mayer B., Pinay G. & Mariotti A. (2013). Long-term fate of nitrate fertilizer in agricultural soils. PNAS. 110 (45) : 18185-18189. doi/10.1073/pnas.1305372110.

Sebilo, Mathieu

2014-05-01

458

Effects of arsenic on nitrate metabolism in arsenic hyperaccumulating and non-hyperaccumulating ferns  

E-print Network

Effects of arsenic on nitrate metabolism in arsenic hyperaccumulating and non Arsenic reduced the activity of nitrate and nitrite reductase more in Pteris ensiformis than Pteris March 2009 Accepted 26 March 2009 Keywords: Arsenic Nitrate metabolism Pteris vittata Arsenic

Ma, Lena

459

Atmospheric Environment 36 (2002) 41594171 Simulations of monthly mean nitrate concentrations in  

E-print Network

Atmospheric Environment 36 (2002) 4159­4171 Simulations of monthly mean nitrate concentrations November 2001; accepted 12 June 2002 Abstract Monthly mean nitrate concentrations in precipitation over National Centers for Environmental Prediction. The distribution of the nitrate concentration

460

MOLECULAR CLONING AND CHARACTERIZATION OF HIGH-AFFINITY NITRATE TRANSPORTERS IN MARINE PHYTOPLANKTON1  

E-print Network

MOLECULAR CLONING AND CHARACTERIZATION OF HIGH-AFFINITY NITRATE TRANSPORTERS IN MARINE including marine phytoplankton. The functional genes encoding high- affinity nitrate transporters (Nrt2 of external N. Key index words: diatom; Dunaliella tertiolecta; Emiliania huxleyi; high-affinity nitrate

Ward, Bess

461

21 CFR 170.60 - Nitrites and/or nitrates in curing premixes.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Nitrites and/or nitrates in curing premixes. 170.60 Section...Decisions § 170.60 Nitrites and/or nitrates in curing premixes. (a) Nitrites and/or nitrates are food additives when...

2013-04-01

462

46 CFR 153.560 - Special requirements for Alkyl (C7-C9) nitrates.  

Code of Federal Regulations, 2011 CFR

...Special requirements for Alkyl (C7-C9) nitrates. 153.560 Section 153.560 Shipping...Special requirements for Alkyl (C7-C9) nitrates. (a) The carriage temperature of octyl nitrates must be maintained below 100 °C...

2011-10-01

463

40 CFR 418.40 - Applicability; description of the ammonium nitrate subcategory.  

Code of Federal Regulations, 2011 CFR

...Applicability; description of the ammonium nitrate subcategory. 418.40 Section...MANUFACTURING POINT SOURCE CATEGORY Ammonium Nitrate Subcategory § 418.40 Applicability; description of the ammonium nitrate subcategory. The provisions...

2011-07-01

464

46 CFR 153.560 - Special requirements for Alkyl (C7-C9) nitrates.  

Code of Federal Regulations, 2010 CFR

...Special requirements for Alkyl (C7-C9) nitrates. 153.560 Section 153.560 Shipping...Special requirements for Alkyl (C7-C9) nitrates. (a) The carriage temperature of octyl nitrates must be maintained below 100 °C...

2010-10-01

465

46 CFR 153.560 - Special requirements for Alkyl (C7-C9) nitrates.  

Code of Federal Regulations, 2012 CFR

...Special requirements for Alkyl (C7-C9) nitrates. 153.560 Section 153.560 Shipping...Special requirements for Alkyl (C7-C9) nitrates. (a) The carriage temperature of octyl nitrates must be maintained below 100 °C...

2012-10-01

466

40 CFR 415.530 - Applicability; description of the silver nitrate production subcategory.  

Code of Federal Regulations, 2012 CFR

...Applicability; description of the silver nitrate production subcategory. 415.530...MANUFACTURING POINT SOURCE CATEGORY Silver Nitrate Production Subcategory § 415.530 Applicability; description of the silver nitrate production subcategory. The...

2012-07-01

467

40 CFR 415.530 - Applicability; description of the silver nitrate production subcategory.  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the silver nitrate production subcategory. 415.530...MANUFACTURING POINT SOURCE CATEGORY Silver Nitrate Production Subcategory § 415.530 Applicability; description of the silver nitrate production subcategory. The...

2010-07-01

468

46 CFR 153.560 - Special requirements for Alkyl (C7-C9) nitrates.  

Code of Federal Regulations, 2013 CFR

...Special requirements for Alkyl (C7-C9) nitrates. 153.560 Section 153.560 Shipping...Special requirements for Alkyl (C7-C9) nitrates. (a) The carriage temperature of octyl nitrates must be maintained below 100 °C...

2013-10-01

469

40 CFR 415.530 - Applicability; description of the silver nitrate production subcategory.  

Code of Federal Regulations, 2013 CFR

...Applicability; description of the silver nitrate production subcategory. 415.530...MANUFACTURING POINT SOURCE CATEGORY Silver Nitrate Production Subcategory § 415.530 Applicability; description of the silver nitrate production subcategory. The...

2013-07-01

470

21 CFR 170.60 - Nitrites and/or nitrates in curing premixes.  

...2014-04-01 false Nitrites and/or nitrates in curing premixes. 170.60 Section...Decisions § 170.60 Nitrites and/or nitrates in curing premixes. (a) Nitrites and/or nitrates are food additives when...

2014-04-01

471

21 CFR 524.1132 - Hydrocortisone aceponate, miconazole nitrate, gentamicin sulfate otic suspension.  

Code of Federal Regulations, 2013 CFR

... Hydrocortisone aceponate, miconazole nitrate, gentamicin sulfate otic suspension... Hydrocortisone aceponate, miconazole nitrate, gentamicin sulfate otic suspension...hydrocortisone aceponate, 15.1 mg of miconazole nitrate, and 1,505 micrograms of...

2013-04-01

472

48. U.S. NITRATE PLANT UNDER CONSTRUCTION, VIEW LOOKING N.E. AT ...  

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

48. U.S. NITRATE PLANT UNDER CONSTRUCTION, VIEW LOOKING N.E. AT THE AMMONIUM NITRATE BUILDING UNDER CONSTRUCTION, AUGUST 24, 1918. - United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Muscle Shoals, Colbert County, AL

473

21 CFR 170.60 - Nitrites and/or nitrates in curing premixes.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Nitrites and/or nitrates in curing premixes. 170.60 Section...Decisions § 170.60 Nitrites and/or nitrates in curing premixes. (a) Nitrites and/or nitrates are food additives when...

2012-04-01

474

40 CFR 418.40 - Applicability; description of the ammonium nitrate subcategory.  

Code of Federal Regulations, 2013 CFR

...Applicability; description of the ammonium nitrate subcategory. 418.40 Section...MANUFACTURING POINT SOURCE CATEGORY Ammonium Nitrate Subcategory § 418.40 Applicability; description of the ammonium nitrate subcategory. The provisions...

2013-07-01

475

21 CFR 524.1132 - Hydrocortisone aceponate, miconazole nitrate, gentamicin sulfate otic suspension.  

Code of Federal Regulations, 2012 CFR

... Hydrocortisone aceponate, miconazole nitrate, gentamicin sulfate otic suspension... Hydrocortisone aceponate, miconazole nitrate, gentamicin sulfate otic suspension...hydrocortisone aceponate, 15.1 mg of miconazole nitrate, and 1,505 micrograms of...

2012-04-01

476

40 CFR 418.40 - Applicability; description of the ammonium nitrate subcategory.  

Code of Federal Regulations, 2012 CFR

...Applicability; description of the ammonium nitrate subcategory. 418.40 Section...MANUFACTURING POINT SOURCE CATEGORY Ammonium Nitrate Subcategory § 418.40 Applicability; description of the ammonium nitrate subcategory. The provisions...

2012-07-01

477

40 CFR 418.40 - Applicability; description of the ammonium nitrate subcategory.  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the ammonium nitrate subcategory. 418.40 Section...MANUFACTURING POINT SOURCE CATEGORY Ammonium Nitrate Subcategory § 418.40 Applicability; description of the ammonium nitrate subcategory. The provisions...

2010-07-01

478

40 CFR 415.530 - Applicability; description of the silver nitrate production subcategory.  

Code of Federal Regulations, 2011 CFR

...Applicability; description of the silver nitrate production subcategory. 415.530...MANUFACTURING POINT SOURCE CATEGORY Silver Nitrate Production Subcategory § 415.530 Applicability; description of the silver nitrate production subcategory. The...

2011-07-01

479

78 FR 35258 - Solid Agricultural Grade Ammonium Nitrate from Ukraine: Continuation of Antidumping Duty Order  

Federal Register 2010, 2011, 2012, 2013

...A-823-810] Solid Agricultural Grade Ammonium Nitrate from Ukraine: Continuation of Antidumping...on solid agricultural grade ammonium nitrate from Ukraine would likely lead to continuation...Order: Solid Agricultural Grade Ammonium Nitrate from Ukraine, 66 FR 47451...

2013-06-12

480

Photooxidation of cellulose nitrate: new insights into degradation mechanisms.  

PubMed

Cellulose nitrate (or nitrocellulose) has received considerable interest due to its uses in various applications, such as paints, photographic films and propellants. However, it is considered as one of the primary pollutants in the energetic material industries because it can be degraded to form polluting chemical species. In this work, the UV light degradation of cellulose nitrate films was studied under conditions of artificially accelerated photooxidation. To eliminate the reactivity of nitro groups, the degradation of ethylcellulose was also investigated. Infrared spectroscopy analyses of the chemical modifications caused by the photooxidation of cellulose nitrate films and the resulting formation of volatile products revealed the occurrence of de-nitration and the formation of oxidation photoproducts exhibiting lactone and anhydride functions. The impact of these chemical modifications on the mechanical and thermal properties of cellulose nitrate films includes embrittlement and lower temperatures of ignition when used as a propellant. PMID:24685530

Berthumeyrie, Sebastien; Collin, Steeve; Bussiere, Pierre-Olivier; Therias, Sandrine

2014-05-15

481

Acute barium nitrate intoxication treated by hemodialysis.  

PubMed

A 22-year-old male was admitted to hospital with diarrhea and vomiting, cardiac arrhythmias, severe hypokalemia and gradual onset of muscular weakness. A potassium infusion was started, but for several hours serum potassium remained low. Evidence of toxic ingestion was initially lacking. When it became clear -- after a considerable delay -- that the patient had ingested barium nitrate, hemodialysis was started. This resulted in rapid clinical improvement with correction of hypokalemia and restored muscular function. Intoxication with barium causes hypokalemia, arrhythmias, muscular weakness and paralysis, often requiring respiratory support. This patient presented with symptoms typical of severe barium intoxication, non-responsive to potassium supplementation. There are few published reports on the use of hemodialysis in barium poisoning. This case confirms the possible benefit of hemodialysis in severe cases, where potassium supplementation alone is insufficient. PMID:15675995

Bahlmann, H; Lindwall, R; Persson, H

2005-01-01

482

Removal of gadolinium nitrate from heavy water  

SciTech Connect

Work was conducted to develop a cost-effective process to purify 181 55-gallon drums containing spent heavy water moderator (D2O) contaminated with high concentrations of gadolinium nitrate, a chemical used as a neutron poison during former nuclear reactor operations at the Savannah River Site (SRS). These drums also contain low level radioactive contamination, including tritium, which complicates treatment options. Presently, the drums of degraded moderator are being stored on site. It was suggested that a process utilizing biological mechanisms could potentially lower the total cost of heavy water purification by allowing the use of smaller equipment with less product loss and a reduction in the quantity of secondary waste materials produced by the current baseline process (ion exchange).

Wilde, E.W.

2000-03-22

483

Synthetic protocols for the nitration of corroles  

PubMed Central

The modification of peripheral positions of corroles by introduction of nitro groups is an important functionalization of this macrocycle. The nitro substituent strongly influences the corrole behavior leading to the preparation of macrocycles with different properties, which can be of interest for their exploitation as catalysts, sensing layers in chemical sensors or in the field of supramolecular chemistry. In the last few years we have developed different routes for the ?-nitration of the corrole ring, and we report here novel synthetic protocols which can allow the formation of tri- and tetranitro derivatives, as demonstrated by X-ray analysis. In all of the methodologies used, the presence of isocorrole species as reaction intermediates was established, which regenerated the corresponding corrole by metal insertion. PMID:22287833

Pomarico, Giuseppe; Fronczek, Frank R.; Nardis, Sara; Smith, Kevin M.; Paolesse, Roberto

2012-01-01

484

Dissimilatory nitrate reduction by a strain of Clostridium butyricum isolated from estuarine sediments  

Microsoft Academic Search

Nitrate dissimilation in chemostat grown cultures ofClostridium butyricum SS6 has been investigated. Sucrose limited cultures grown on nitrate produced nitrite as the principal end-product of nitrate reduction whilst under nitrate-limiting conditions ammonia accumulated in the spent media. Nitrate reduction was accompanied by the synthesis of a soluble nitrate reductase (123 nmol·NADH oxidised · min-1 · mg protein-1) and in addition,

S. M. Keith; G. T. MacFarlane; R. A. Herbert

1982-01-01

485

Thermal decomposition of nitrated tributyl phosphate  

SciTech Connect

Extended contact between heated mixtures of tri-n-butyl phosphate (TBP) and aqueous solutions of nitric acid and/or heavy metal nitrate salts at elevated temperatures can lead to exothermic reactions of explosive violence. Most solvent extraction operations are conducted at ambient conditions without heating TBP and have been performed safely for decades, but several explosions involving TBP have occurred in the US, Canada, and the former Soviet Union. This investigation was undertaken to characterize the products of thermal decomposition of both single- and two-phase mixtures of TBP, nitric acid, and water under a variety of conditions. The data indicate that the extent of reaction and the rate of gaseous product formation are affected by the presence of Zr{sup 4+}, distillation compared with reflux conditions, temperature, water/HNO{sub 3} and HNO{sub 3}/TBP ratios, and whether the decomposition occurs under constant pressure or constant volume conditions. Higher reaction temperatures accelerate the rate of decomposition, but the extent of decomposition, as measured by the quantity of gaseous products, was greater at lower temperatures when the decomposition was performed under distillation conditions. Higher gas production occurs under reflux conditions, lower H{sub 2}O/HNO{sub 3} ratios, and when a separate water-HNO{sub 3} phase is initially present. The major gaseous products include N{sub 2}, CO, CO{sub 2}, NO, and N{sub 2}O. Measurable amounts of NO{sub 2} were not present in the final product mixture, although an orange color suggesting the presence of NO{sub 2} was observed in the early stages of decomposition. The major liquid products were dibutyl phosphoric acid, butyl nitrate, and water. Small amounts of C{sub 1}-C{sub 4} carboxylic acids were also present. Because of the small sample sizes that were employed and the isothermal conditions of the decomposition, runaway reactions were not observed. Some possible reaction pathways are considered.

Hou, Y.; Barefield, E.K.; Tedder, D.W.; Abdel-Khalik, S.I. [Georgia Inst. of Technology, Atlanta, GA (United States)

1996-03-01

486

Electrocatalytic reduction of nitrate in water.  

PubMed

Nitrate (NO(3)(-)) contamination of groundwater is a common problem throughout intensive agricultural areas (nonpoint source pollution). Current processes (e.g., ion exchange, membrane separation) for NO(3)(-) removal have various disadvantages. The objective of this study was to evaluate an electrocatalytic reduction process to selectively remove NO(3)(-) from groundwater associated with small agricultural communities. A commercially available ELAT (E-Tek Inc., Natick, MA) carbon cloth with a 30% surface coated Rh (rhodium) (1microg x cm(-1)) was tested at an applied potential of -1.5 V versus standard calomel electrode (SCE) with a Pt auxiliary electrode. Electrocatalytic reduction process (electrolysis) of NO(3)(-) was tested with cyclic voltammetry (CV) in samples containing NO(3)(-) and 0.1M NaClO(4)(-). Nitrate and NO(2)(-) concentrations in test solutions and groundwater samples were analyzed by ion chromatography (IC). The presence of Rh on the carbon cloth surface resulted in current increase of 36% over uncoated carbon cloths. The electrocatalysis experiments using Rh coated carbon cloth resulted in reduction of NO(3)(-) and NO(2)(-) on a timescale of minutes. Nitrite is produced as a product, but is rapidly consumed upon further electrolysis. Field groundwater samples subjected to electrocatalysis experiments, without the addition of NaClO(4)(-) electrolyte, also exhibited removal of NO(3)(-) on a timescale of minutes. Overall, results suggest that at an applied potential of -1.5 V with respect to SCE, Rh coated carbon cloth can reduce NO(3)(-) concentrations in field groundwater samples from 73 to 39 mg/L (16.58 to 8.82 mg/L as N) on a timescale range of 40-60 min. The electrocatalytic reduction process described in this study may prove useful for removing NO(3)(-) and NO(2)(-) from groundwater associated with nonpoint source pollution. PMID:12727264

Peel, J W; Reddy, K J; Sullivan, B P; Bowen, J M

2003-05-01

487

REMOVAL OF ADDED NITRATE IN COTTON BURR COMPOST, MULCH COMPOST, AND PEAT: MECHANISMS AND POTENTIAL USE FOR GROUNDWATER NITRATE REMEDIATION  

EPA Science Inventory

We conducted batch tests on the nature and kinetics of removal of added nitrate in cotton burr compost, mulch compost, and sphagnum peat that may be potentially used in a permeable reactive barrier (PRB) for groundwater nitrate remediation. A rigorous steam autoclaving protocol (...

488

Numerical Analysis of the Transport and Fate of Nitrate in the Soil and Nitrate Leaching to Drains  

Microsoft Academic Search

In this study, the transport and fate of nitrate within the soil profile and nitrate leaching to drains were analyzed by comparing historic field data with the simulation results of the DRAINMOD model. The model was used to simulate the performance of the nitrogen transport and transformation of the Hooibeekhoeve experiment, situated in the sandy region of the Kempen (Belgium),

Alaa El-Sadek; Mona Radwan; Jan Feyen

2001-01-01

489

NITRATE REMOVAL FROM CONTAMINATED WATER SUPPLIES. VOLUME 1. DESIGN AND INITIAL PERFORMANCE OF A NITRATE REMOVAL PLANT  

EPA Science Inventory

The report reviews the design, construction, and operation of a 1-mgd nitrate removal plant in McFarland, CA. The plant treats well water for domestic use. Nitrates are reduced from approximately 15.8 mg NO3-N/L to well below the maximum contaminant level of 10 mg NO3-N/L. Contin...

490

Water and waste water analysis for nitrate via nitration of salicylic acid  

Microsoft Academic Search

A method is presented which allows rapid nitrate analyses of water and waste water samples and soil extracts. The linear working range is typically 0.5–30 mg NO 3?N\\/liter and duplicate analysis of samples and standards routinely produces confidence limits for the regression estimate of ? ±0.1 mg NO 3?N\\/liter at the 95% confidence level. Nitrite, formaldehyde and soluble Iron, as

W. P. Robarge; A. Edwards; B. Johnson

1983-01-01

491

Size distributions of ammonium nitrate and sodium nitrate in atmospheric aerosols  

SciTech Connect

An analytical method was developed to determine separately NH/sub 4/NO/sub 3/ and NaNO/sub 3/ in atmospheric aerosols by the difference of their thermal stability. Volatile NH/sub 4/NO/sub 3/ was recovered in a cold trap by heating a filter sample on which ambient aerosols were collected in an electric furnace under a gas flow system. The heating condition of 160 /sup 0/C for 1 h under 1 L/min N/sub 2/ was concluded to be optimum. On the other hand, nonvolatile NaNO/sub 3/ was evaluated as the difference between the total nitrate measured without the heating treatment and volatile nitrate. It was directly observed by using an Andersen sampler that the bimodal total nitrate size distribution consisted of NH/sub 4/NO/sub 3/ size distribution with a peak in the fine particle size range and NaNO/sub 3/ size distribution with a peak in the coarse particle size range. In addition, their distributions showed the very distinguishable variation by season which can be explained by the temperature dependence of the NH/sub 4/NO/sub 3/ vapor pressure.

Yoshizumi, K.; Hoshi, A.

1985-01-01

492

Quantification of nitrate-? interactions and selective transport of nitrate using calix[4]pyrroles with two aromatic walls.  

PubMed

Herein we disclose the results of our investigations regarding the interactions between the biologically relevant nitrate oxoanion and several "two-wall" aryl-extended calix[4]pyrroles. There exists a clear relationship between the electronic nature of the aromatic walls of the calix[4]pyrroles and the stability of the nitrate?calix[4]pyrrole complex. This suggests that NO3(-)-? interactions have an important electrostatic component. We provide energetic estimates for the interaction of nitrate with several phenyl derivatives. Additionally, we report solid-state evidence for a preferred binding geometry of the nitrate anion included in the calix[4]pyrroles. Finally, the "two-wall" aryl-extended calix[4]pyrroles show excellent activity in ion transport through lipid-based lamellar membranes. Notably the best anion transporters are highly selective for transport of nitrate over other anions. PMID:23672588

Adriaenssens, Louis; Estarellas, Carolina; Vargas Jentzsch, Andreas; Martinez Belmonte, Marta; Matile, Stefan; Ballester, Pablo

2013-06-01

493

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

E-print Network

(dimethylamino)zirconium (TDMAZ) and ammonia gas as precursors at atmospheric pressure. Tungsten wires and zirconia-silica (ZrO2-SiO2) microspheres were used as the substrates for the coating experiments. The substrate temperature and precursor gas flow were manipulated...

Arrieta, Marie

2012-10-19

494

Bonding Interactions Generated by Halogen Oxidation of Zirconium(IV) Redox-Active Ligand Complexes  

E-print Network

-based redox activity.1 Three basic oxidation states domi- nate the coordination chemistry of catecholate· -· Bonding Interactions Generated by Halogen Oxidation of Zirconium(IV) Redox-Active Ligand of pdaLi2 with ZrCl4, reacts rapidly with halogen oxidants to afford the new product ZrX2(disq)2 (3, X

Baik, Mu-Hyun

495

The 5-year Results of an Oxidized Zirconium Femoral Component for TKA  

PubMed Central

Osteolysis secondary to polyethylene wear is one of the major factors limiting long-term performance of TKA. Oxidized zirconium is a new material that combines the strength of a metal with the wear properties of a ceramic. It remains unknown whether implants with a zirconium femoral component can be used safely in TKA. To answer that question, we reviewed, at a minimum of 5 years, the clinical outcome and survivorship of a ceramic-surfaced oxidized zirconium femoral component implanted during 98 primary TKAs between April 2001 and December 2003. Survivorship was 98.7% at 7 years postoperatively. No revision was necessary and only one component failed because of aseptic loosening. Mean Knee Society score improved from 36 to 89. No adverse events were observed clinically or radiologically. These results justify pursuing the use of oxidized zirconium as an alternative bearing surface for a femoral component in TKA. Level of Evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence. PMID:19798541

Innocenti, Massimo; Carulli, Christian; Matassi, Fabrizio; Villano, Marco

2009-01-01

496

Equilibrium isotherms for harmful ions sorption using nano zirconium vanadate ion exchanger  

Microsoft Academic Search

Harmful ions such as cesium, cobalt and nickel were removed from aqueous solutions using nano zirconium vanadate ion exchangers that prepared using three different techniques and their organic hybrids. Different processing parameters that affect on sorption efficiency were studied. All prepared ion exchangers and their composites have high uptake affinity for cesium removal. The removal capacities of the ion exchangers

M. M. Abd El-Latif; M. F. Elkady

2010-01-01

497

Recycle of Zirconium from Used Nuclear Fuel Cladding: A Major Element of Waste Reduction  

SciTech Connect

Feasibility tests were initiated to determine if the zirconium in commercial used nuclear fuel (UNF) cladding can be recovered in sufficient purity to permit re-use, and if the recovery process can be operated economically. Initial tests are being performed with unirradiated, non-radioactive samples of various types of Zircaloy materials that are used in UNF cladding to develop the recovery process and determine the degree of purification that can be obtained. Early results indicate that quantitative recovery can be accomplished and product contamination with alloy constituents can be controlled sufficiently to meet purification requirements. Future tests with actual radioactive UNF cladding are planned. The objective of current research is to determine the feasibility of recovery and recycle of zirconium from used fuel cladding wastes. Zircaloy cladding, which contains 98+% of hafnium-free zirconium, is the second largest mass, on average {approx}25 wt %, of the components in used U.S. light-water-reactor fuel assemblies. Therefore, recovery and recycle of the zirconium would enable a large reduction in geologic waste disposal for advanced fuel cycles. Current practice is to compact or grout the cladding waste a