Physical properties of the stratospheric aerosols

NASA Technical Reports Server (NTRS)

Toon, O. B.; Pollack, J. B.

1973-01-01

A comparison of the equilibrium vapor pressure over nitric acid solutions with observed water and nitric acid partial pressures in the stratosphere implies that nitric acid cannot be present as an aerosol particle in the lower stratosphere. A similar comparison for sulfuric acid solutions indicates that sulfuric acid aerosol particles are 75% H2SO4 by weight in water, in good agreement with direct observations. The freezing curve of H2SO4 solutions requires that the H2SO4 aerosol particles be solid or supercooled. The equilibrium vapor pressure of H2SO4 in the stratosphere is of the order of 20 picotorr. At stratospheric temperatures, ammonium sulfate is in a ferroelectric phase. As a result, polar molecules may form a surface coating on these aerosols, which may be a fertile ground for further chemical reaction.

Ignition Delays of Alkyl Thiophosphites with White and Red Fuming Nitric Acids Within Temperature Range 80 to -105 F

NASA Technical Reports Server (NTRS)

Miller, Riley O; Ladanyi, Dezso J

1953-01-01

Ignition delays of alkyl thiophosphites were obtained in a modified open-cup apparatus and a small-scale rocket engine apparatus. At -40 F, mixed alkyl thiophosphites gave short delays with white fuming nitric acid containing 2 percent water and red fuming nitric acids of widely varying compositions. At -40 F and higher, triethyl trithiophosphite blended with as much as 40 percent n-heptane gave satisfactory self-igniting properties at temperatures as low as -76 F.

Nucleation of nitric acid hydrates in polar stratospheric clouds by meteoric material

NASA Astrophysics Data System (ADS)

James, Alexander D.; Brooke, James S. A.; Mangan, Thomas P.; Whale, Thomas F.; Plane, John M. C.; Murray, Benjamin J.

2018-04-01

Heterogeneous nucleation of crystalline nitric acid hydrates in polar stratospheric clouds (PSCs) enhances ozone depletion. However, the identity and mode of action of the particles responsible for nucleation remains unknown. It has been suggested that meteoric material may trigger nucleation of nitric acid trihydrate (NAT, or other nitric acid phases), but this has never been quantitatively demonstrated in the laboratory. Meteoric material is present in two forms in the stratosphere: smoke that results from the ablation and re-condensation of vapours, and fragments that result from the break-up of meteoroids entering the atmosphere. Here we show that analogues of both materials have a capacity to nucleate nitric acid hydrates. In combination with estimates from a global model of the amount of meteoric smoke and fragments in the polar stratosphere we show that meteoric material probably accounts for NAT observations in early season polar stratospheric clouds in the absence of water ice.

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; comparison of a nitric acid in-bottle digestion procedure to other whole-water digestion procedures

USGS Publications Warehouse

Garbarino, John R.; Hoffman, Gerald L.

1999-01-01

A hydrochloric acid in-bottle digestion procedure is used to partially digest wholewater samples prior to determining recoverable elements by various analytical methods. The use of hydrochloric acid is problematic for some methods of analysis because of spectral interference. The inbottle digestion procedure has been modified to eliminate such interference by using nitric acid instead of hydrochloric acid in the digestion. Implications of this modification are evaluated by comparing results for a series of synthetic whole-water samples. Results are also compared with those obtained by using U.S. Environmental Protection Agency (1994) (USEPA) Method 200.2 total-recoverable digestion procedure. Percentage yields that use the nitric acid inbottle digestion procedure are within 10 percent of the hydrochloric acid in-bottle yields for 25 of the 26 elements determined in two of the three synthetic whole-water samples tested. Differences in percentage yields for the third synthetic whole-water sample were greater than 10 percent for 16 of the 26 elements determined. The USEPA method was the most rigorous for solubilizing elements from particulate matter in all three synthetic whole-water samples. Nevertheless, the variability in the percentage yield by using the USEPA digestion procedure was generally greater than the in-bottle digestion procedure, presumably because of the difficulty in controlling the digestion conditions accurately.

Real refractive indices of infrared-characterized nitric-acid/ice films: Implications for optical measurements of polar stratospheric clouds

NASA Technical Reports Server (NTRS)

Middlebrook, Ann M.; Berland, Brian S.; George, Steven M.; Tolbert, Margaret A.; Toon, Owen B.

1994-01-01

The infrared spectra of nitric-acid/ice films representative of polar stratospheric clouds (PSCs) were collected with simultaneous optical interference measurements to determine the real refractive indices at lambda = 632 nm. Ice and amphorous nitric-acid/ice films were prepared by condensation of water and nitric acid vapors onto a wedged Al2O3 substrate. The real refractive indices of these films were determined from the optical interference of a reflected helium-neon laser during film growth. The indices of the amphorous films varied smoothly from n = 1.30 for ice to n = 1.49 for nitric acid, similar to observations in previous work. We were unable to obtain the refractive index of crystlline films during adsorption because of optical scattering caused by surface roughness. Therefore crystlline nitric acid hydrate films were prepared by annealing amphorous nitric-acid/ice films. Further heating caused desorption of the crystalline hydrate films. During desorption, the refractive indices for ice, NAM (nitric acid monohydrate), alpha- and beta-NAT (nitric acid trihydrate) films were measured using the optical interference technique. In agreement with earlier data, the real refractive indices for ice and NAM determined in desorption were n = 1.30 +/- 0.01 and n = 1.53 +/- 0.03, respectively. The real refractive indices for alpha- and beta-NAT were found to be n = 1.51 +/- 0.01 and n greater than or equal to 1.46, respectively. Our measurements also suggest that the shape of crystalline nitric acid particles may depend on whether they nucleate from the liquid or by vapor deposition. If confirmed by future studies, this observation may provide a means of distinguishing the nucleation mechanism of crystalline PSCs.

Burial of gas-phase HNO(3) by growing ice surfaces under tropospheric conditions.

PubMed

Ullerstam, Maria; Abbatt, Jonathan P D

2005-10-21

The uptake of gas-phase nitric acid by ice surfaces undergoing growth by vapor deposition has been performed for the first time under conditions of the free troposphere. The investigation was performed using a coated-wall flow tube coupled to a chemical ionization mass spectrometer, at nitric acid partial pressures between 10(-7) and 10(-6) hPa, at 214, 229 and 239 K. Ice surfaces were prepared as smooth ice films from ultra-pure water. During the experiments an excess flow of water vapor was added to the carrier gas flow and the existing ice surfaces grew by depositing water vapor. The average growth rates ranged from 0.7-5 microm min(-1), values similar to those which prevail in some portions of the atmosphere. With growing ice the long term uptake of nitric acid is significantly enhanced compared to an experiment performed at equilibrium, i.e. at 100% relative humidity (RH) with respect to ice. The fraction of HNO(3) that is deposited onto the growing ice surface is independent of the growth rate and may be driven by the solubility of the nitric acid in the growing ice film rather than by condensation kinetics alone.

49 CFR 173.158 - Nitric acid.

Code of Federal Regulations, 2012 CFR

2012-10-01

...” following the steel designation on containers subject to stress relieving or heat treatment during... nitric acid, the following are permissible: (A) Type 304 heat-treated (quenched in water at 1040 °C (1900 °F)), (B) Stabilized Type 347 in the as-welded condition, (C) Stabilized Type 347 stress-relieved...

49 CFR 173.158 - Nitric acid.

Code of Federal Regulations, 2014 CFR

2014-10-01

...” following the steel designation on containers subject to stress relieving or heat treatment during... nitric acid, the following are permissible: (A) Type 304 heat-treated (quenched in water at 1040 °C (1900 °F)), (B) Stabilized Type 347 in the as-welded condition, (C) Stabilized Type 347 stress-relieved...

49 CFR 173.158 - Nitric acid.

Code of Federal Regulations, 2013 CFR

2013-10-01

...” following the steel designation on containers subject to stress relieving or heat treatment during... nitric acid, the following are permissible: (A) Type 304 heat-treated (quenched in water at 1040 °C (1900 °F)), (B) Stabilized Type 347 in the as-welded condition, (C) Stabilized Type 347 stress-relieved...

Determination of Ultramicro Quantities of Elemental Phosphorus in Water by Neutron Activation Analysis.

DTIC Science & Technology

1977-06-10

HYPOPHOSPHITE :80x I0O4 PHOSPHITE I1.8 x 10- PHOSPHATE 8.0 x 1- SODIUM SALTS: 10 mg/I 16 mad NSWC/WOL TR 77-49 TABLE 3 RECOVERY OF PHOSPHORUS IN NITRIC ACID...of the benzene extract by shaking with aqueous nitric acid resulted in nitric acid oxidation of P4 to phosphate ion. which then nassed into the...aqueous phase. The treatment was carrie out in a mechanical shaker or magnetic stirrer. The aqueous layer, containing phosphate , was isolated in a

Ferulic acid and its water-soluble derivatives inhibit nitric oxide production and inducible nitric oxide synthase expression in rat primary astrocytes.

PubMed

Kikugawa, Masaki; Ida, Tomoaki; Ihara, Hideshi; Sakamoto, Tatsuji

2017-08-01

We recently reported that two water-soluble derivatives of ferulic acid (1-feruloyl glycerol, 1-feruloyl diglycerol) previously developed by our group exhibited protective effects against amyloid-β-induced neurodegeneration in vitro and in vivo. In the current study, we aimed to further understand this process by examining the derivatives' ability to suppress abnormal activation of astrocytes, the key event of neurodegeneration. We investigated the effects of ferulic acid (FA) derivatives on nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression in rat primary astrocytes. The results showed that these compounds inhibited NO production and iNOS expression in a concentration-dependent manner and that the mechanism underlying these effects was the suppression of the nuclear factor-κB pathway. This evidence suggests that FA and its derivatives may be effective neuroprotective agents and could be useful in the treatment of neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease.

Growth of nitric acid hydrates on thin sulfuric acid films

NASA Technical Reports Server (NTRS)

Iraci, Laura T.; Middlebrook, Ann M.; Wilson, Margaret A.; Tolbert, Margaret A.

1994-01-01

Type I polar stratospheric clouds (PSCs) are thought to nucleate and grow on stratospheric sulfate aerosols (SSAs). To model this system, thin sulfuric acid films were exposed to water and nitric acid vapors (1-3 x 10(exp -4) Torr H2O and 1-2.5 x 10(exp -6) Torr HNO3) and subjected to cooling and heating cycles. Fourier Transform Infrared (FTIR) spectroscopy was used to probe the phase of the sulfuric acid and to identify the HNO3/H2O films that condensed. Nitric acid trihydrate (NAT) was observed to grow on crystalline sulfuric acid tetrahydrate (SAT) films. NAT also condensed in/on supercooled H2SO4 films without causing crystallization of the sulfuric acid. This growth is consistent with NAT nucleation from ternary solutions as the first step in PSC formation.

Nitric Acid and Water Extraction by T2EHDGA in n -Dodecane

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, Emily L.; Holfeltz, Vanessa E.; Hall, Gabriel B.

Liquid-liquid distribution behavior of nitric acid (HNO3) and water by a diglycolamide ligand, N,N,N',N'-tetra-2-ethylhexyldiglycolamide (T2EHDGA) into n-dodecane diluent was investigated. Spectroscopic FTIR and NMR characterization of the organic extraction solutions indicate T2EHDGA carbonyl coordinates HNO3 and progressively aggregates at high acid conditions. Water extraction increases in the presence of HNO3. The experimentally observed distribution of HNO3 was modeled using the computer program, SXLSQI. The results indicated that the formation of two organic phase species—HNO3·T2EHDGA and (HNO3)2·T2EHDGA—satisfactory describes the acid transport behavior. Temperature dependent solvent extraction studies allowed for determination of thermodynamic extraction constants and ΔH and ΔS parameters for themore » corresponding extractive processes.« less

Process for making a noble metal on tin oxide catalyst

NASA Technical Reports Server (NTRS)

Upchurch, Billy T. (Inventor); Davis, Patricia (Inventor); Miller, Irvin M. (Inventor)

1989-01-01

A quantity of reagent grade tin metal or compound, chloride-free, and high-surface-area silica spheres are placed in deionized water, followed by deaerating the mixture by boiling and adding an oxidizing agent, such as nitric acid. The nitric acid oxidizes the tin to metastannic acid which coats the spheres because the acid is absorbed on the substrate. The metastannic acid becomes tin oxide upon drying and calcining. The tin-oxide coated silica spheres are then placed in water and boiled. A chloride-free precious metal compound in aqueous solution is then added to the mixture containing the spheres, and the precious metal compound is reduced to a precious metal by use of a suitable reducing agent such as formic acid. Very beneficial results were obtained using the precious metal compound tetraammine platinum(II) hydroxide.

The Effect of Acid Pre-Treatment using Acetic Acid and Nitric Acid in The Production of Biogas from Rice Husk during Solid State Anaerobic Digestion (SS-AD)

NASA Astrophysics Data System (ADS)

Nugraha, Winardi Dwi; Syafrudin; Keumala, Cut Fadhila; Matin, Hasfi Hawali Abdul; Budiyono

2018-02-01

Pretreatment during biogas production aims to assist in degradation of lignin contained in the rice husk. In this study, pretreatment which is used are acid and biological pretreatment. Acid pretreatment was performed using acetic acid and nitric acid with a variety levels of 3% and 5%. While biological pretreatment as a control variable. Acid pretreatment was conducted by soaking the rice straw for 24 hours with acid variation. The study was conducted using Solid State Anaerobic Digestion (SS-AD) with 21% TS. Biogas production was measured using water displacement method every two days for 60 days at room temperature conditions. The results showed that acid pretreatment gave an effect on the production of biogas yield. The yield of the biogas produced by pretreatment of acetic acid of 5% and 3% was 43.28 and 45.86 ml/gr.TS. While the results without pretreatment biogas yield was 29.51 ml/gr.TS. The results yield biogas produced by pretreatment using nitric acid of 5% and 3% was 12.14 ml/gr.TS and 21.85 ml/gr.TS. Results biogas yield with acetic acid pretreatment was better than the biogas yield results with nitric acid pretreatment.

Ignition Delay Experiments with Small-scale Rocket Engine at Simulated Altitude Conditions Using Various Fuels with Nitric Acid Oxidants / Dezso J. Ladanyi

NASA Technical Reports Server (NTRS)

Ladanyi, Dezso J

1952-01-01

Ignition delay determinations of several fuels with nitric oxidants were made at simulated altitude conditions utilizing a small-scale rocket engine of approximately 50 pounds thrust. Included in the fuels were aniline, hydrazine hydrate, furfuryl alcohol, furfuryl mercaptan, turpentine, and mixtures of triethylamine with mixed xylidines and diallyaniline. Red fuming, white fuming, and anhydrous nitric acids were used with and without additives. A diallylaniline - triethylamine mixture and a red fuming nitric acid analyzing 3.5 percent water and 16 percent NO2 by weight was found to have a wide temperature-pressure ignition range, yielding average delays from 13 milliseconds at 110 degrees F to 55 milliseconds at -95 degrees F regardless of the initial ambient pressure that ranged from sea-level pressure altitude of 94,000 feet.

Chem I Supplement: Emphasis on Acids and Bases

ERIC Educational Resources Information Center

Journal of Chemical Education Staff

1977-01-01

Provides supplementary notes on acids and bases suitable for secondary school chemistry instruction, including acidity in solid and natural waters, acidity balance in body chemistry, acid and basic foods, pH values of common fluids, examples of drugs, and commercial preparation of nitric acid. (SL)

Study of Pulsed Columns with the System. Uranyl Nitrate-Nitric Acid-Water- Tributylphosphate; ETUDE DES COLONNES A PULSATIONS A L'AIDE DU SYSTEME NITRATE D'URANYLE-ACIDE NITRIQUEEAU-TRIBUTYLPHOSPHATE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Durandet, J.; Defives, D.; Choffe, B.

1959-10-31

The performsnce of a pulsed column with perforated plates was studied with the aid of a uranyl nitrate-nitric acid --water --tributyl phosphate system. The extraction of uranium from an aqueous acidic solution by an organic solvent and the extraction of uranium from organic solutions by water were the two cases investigated. The variation of the efficiency and the capacity of the pulsed column was determined as a function of the pulse amplitude and frequency, of the total flow rate, of the diameter of the holes, and of the choice of dispersed phase. The results showed that for a given amplitudemore » and total flow rate the efficiency has a maximum with an increase in frequency. (J.S.R.)« less

PROCESSING OF NEUTRON-IRRADIATED URANIUM

DOEpatents

Hopkins, H.H. Jr.

1960-09-01

An improved "Purex" process for separating uranium, plutonium, and fission products from nitric acid solutions of neutron-irradiated uranium is offered. Uranium is first extracted into tributyl phosphate (TBP) away from plutonium and fission products after adjustment of the acidity from 0.3 to 0.5 M and heating from 60 to 70 deg C. Coextracted plutonium, ruthenium, and fission products are fractionally removed from the TBP by three scrubbing steps with a 0.5 M nitric acid solution of ferrous sulfamate (FSA), from 3.5 to 5 M nitric acid, and water, respectively, and the purified uranium is finally recovered from the TBP by precipitation with an aqueous solution of oxalic acid. The plutonium in the 0.3 to 0.5 M acid solution is oxidized to the tetravalent state with sodium nitrite and extracted into TBP containing a small amount of dibutyl phosphate (DBP). Plutonium is then back-extracted from the TBP-DBP mixture with a nitric acid solution of FSA, reoxidized with sodium nitrite in the aqueous strip solution obtained, and once more extracted with TBP alone. Finally the plutonium is stripped from the TBP with dilute acid, and a portion of the strip solution thus obtained is recycled into the TBPDBP for further purification.

Hydrolytic Unzipping of Boron Nitride Nanotubes in Nitric Acid.

PubMed

Kim, Dukeun; Muramatsu, Hiroyuki; Kim, Yoong Ahm

2017-12-01

Boron nitride nanoribbons (BNNRs) have very attractive electrical and optical properties due to their unique edge states and width-related properties. Herein, for the first time, BNNRs were produced by a simple reflux of boron nitride nanotubes (BNNTs) in nitric acid containing water, which had led to unzipped sidewalls through hydrolysis. Their high reactivity that originated from edges was verified via a strong interaction with methylene blue.

Acid Rain: A Selective Bibliography. Second Edition. Bibliography Series Twenty-One.

ERIC Educational Resources Information Center

O'Neill, Gertrudis, Comp.

Acid rain is a term for rain, snow, or other precipitation produced from water vapor in the air reacting with emissions from automobiles, factories, power plants, and other oil and coal burning sources. When these chemical compounds, composed of sulfur oxide and nitrogen oxide, react with water vapor, the result is sulfuric acid and nitric acid.…

Ignition-delay Characteristics in Modified Open-cup Apparatus of Several Fuels with Nitric Acid Oxidants Within Temperature Range 70 to 105 Degrees F

NASA Technical Reports Server (NTRS)

Miller, Riley O

1951-01-01

Fluid properties and low-temperature ignition delays were obtained for approximately 90 fuel-oxidant combinations. A red fuming nitric acid containing approximately 3 percent water and 19 percent nitrogen tetroxide froze at approximately -87 degrees F and ignited several low-viscosity fuel blends of aromatic amines in triethylamine at -76 degrees F and lower. With this acid, the following average ignition delays were obtained with a blend of 30 percent o-toluidine in triethylamine: ...

49 CFR 172.330 - Tank cars and multi-unit tank car tanks.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Hydrogen peroxide and peroxyacetic acid mixtures Nitric acid (other than red fuming) Phosphorus, amorphous Phosphorus, white dry or Phosphorus, white, under water or Phosphorus white, in solution, or Phosphorus, yellow dry or Phosphorus, yellow, under water or Phosphorus, yellow, in solution Phosphorus white, molten...

49 CFR 172.330 - Tank cars and multi-unit tank car tanks.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Hydrogen peroxide and peroxyacetic acid mixtures Nitric acid (other than red fuming) Phosphorus, amorphous Phosphorus, white dry or Phosphorus, white, under water or Phosphorus white, in solution, or Phosphorus, yellow dry or Phosphorus, yellow, under water or Phosphorus, yellow, in solution Phosphorus white, molten...

Evaluation of Military Field-Water Quality. Volume 3. Opportunity Poisons

DTIC Science & Technology

1987-12-01

Acidic chemical cleaners fluoric acid, nitric acid, perchloric Spent acid acid, sulfuric acid Alkalies Miscellaneous caustic products Ammonia, lime...calcium oxide), potassium Alkaline battery fluid hydroxide, sodium hydroxide, sodium Caustic wastewater silicate Cleaning solutions Lye Nonhalogenated...Laboratory chemicals chloride, polychlorinated biphenyls, zinc Paint and varnish removers naphthenate , copper naphthenate , dichloro- Capacitors and

METHOD OF DISSOLVING MASSIVE PLUTONIUM

DOEpatents

Facer, J.F.; Lyon, W.L.

1960-06-28

Massive plutonium can be dissolved in a hot mixture of concentrated nitric acid and a small quantity of hydrofluoric acid. A preliminary oxidation with water under superatmospheric pressure at 140 to 150 deg C is advantageous

Changes in oxidative potential of soil and fly ash after reaction with gaseous nitric acid

NASA Astrophysics Data System (ADS)

Zhan, Ying; Ginder-Vogel, Matthew; Shafer, Martin M.; Rudich, Yinon; Pardo, Michal; Katra, Itzhak; Katoshevski, David; Schauer, James J.

2018-01-01

The goal of this study was to examine the impact of simulated atmospheric aging on the oxidative potential of inorganic aerosols comprised primarily of crustal materials. Four soil samples and one coal fly ash sample were artificially aged in the laboratory through exposure to the vapor from 15.8 M nitric acid solution for 24 h at room temperature. Native and acid-aged samples were analyzed with a cellular macrophage and acellular dithionthreitol assays to determine oxidative potential. Additionally, the samples were analyzed to determine the concentration of 50 elements, both total and the water-soluble fraction of these elements by Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICMS) and crystalline mineral composition using X-ray Diffraction (XRD). The results show that reactions with gaseous nitric acid increase the water-soluble fraction of many elements, including calcium, iron, magnesium, zinc, and lead. The mineral composition analysis documented that calcium-rich minerals present in the soils (e.g., calcite) are converted into different chemical forms, such as calcium nitrate (Ca(NO3)2). The nitric acid aging process, which can occur in the atmosphere, leads to a 200-600% increase in oxidative potential, as measured by cellular and acellular assays. This laboratory study demonstrates that the toxic effects of aged versus freshly emitted atmospheric dust may be quite different. In addition, the results suggest that mineralogical analysis of atmospheric dust may be useful in understanding its degree of aging.

Fabrication of silica ceramic membrane via sol-gel dip-coating method at different nitric acid amount

NASA Astrophysics Data System (ADS)

Kahlib, N. A. Z.; Daud, F. D. M.; Mel, M.; Hairin, A. L. N.; Azhar, A. Z. A.; Hassan, N. A.

2018-01-01

Fabrication of silica ceramics via the sol-gel method has offered more advantages over other methods in the fabrication of ceramic membrane, such as simple operation, high purity homogeneous, well defined-structure and complex shapes of end products. This work presents the fabrication of silica ceramic membrane via sol-gel dip-coating methods by varying nitric acid amount. The nitric acid plays an important role as catalyst in fabrication reaction which involved hydrolysis and condensation process. The tubular ceramic support, used as the substrate, was dipped into the sol of Tetrethylorthosilicate (TEOS), distilled water and ethanol with the addition of nitric acid. The fabricated silica membrane was then characterized by (Field Emission Scanning Electron Microscope) FESEM and (Fourier transform infrared spectroscopy) FTIR to determine structural and chemical properties at different amount of acids. From the XRD analysis, the fabricated silica ceramic membrane showed the existence of silicate hydrate in the final product. FESEM images indicated that the silica ceramic membrane has been deposited on the tubular ceramic support as a substrate and penetrate into the pore walls. The intensity peak of FTIR decreased with increasing of amount of acids. Hence, the 8 ml of acid has demonstrated the appropriate amount of catalyst in fabricating good physical and chemical characteristic of silica ceramic membrane.

77 FR 48433 - New Source Performance Standards Review for Nitric Acid Plants

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-14

...) for nitric acid plants. Nitric acid plants include one or more nitric acid production units (NAPUs... requirements for new nitric acid production units? IV. Summary of Significant Changes Since Proposal A. How is..., Energy, and Economic Impacts of These Standards A. What are the impacts for Nitric Acid Production Units...

Recycling of CdTe photovoltaic waste

DOEpatents

Goozner, Robert E.; Long, Mark O.; Drinkard, Jr., William F.

1999-04-27

A method for extracting and reclaiming metals from scrap CdTe photovoltaic cells and manufacturing waste by leaching the metals in dilute nitric acid, leaching the waste with a leaching solution comprising nitric acid and water, skimming any plastic material from the top of the leaching solution, separating the glass substrate from the liquid leachate, adding a calcium containing base to the leachate to precipitate Cd and Te, separating the precipitated Cd and Te from the leachate, and recovering the calcium-containing base.

Recycling of CdTe photovoltaic waste

DOEpatents

Goozner, R.E.; Long, M.O.; Drinkard, W.F. Jr.

1999-04-27

A method for extracting and reclaiming metals from scrap CdTe photovoltaic cells and manufacturing waste by leaching the metals in dilute nitric acid, leaching the waste with a leaching solution comprising nitric acid and water, skimming any plastic material from the top of the leaching solution, separating the glass substrate from the liquid leachate, adding a calcium containing base to the leachate to precipitate Cd and Te, separating the precipitated Cd and Te from the leachate, and recovering the calcium-containing base. 3 figs.

Methods of decontaminating surfaces and related compositions

DOEpatents

Demmer, Ricky L.; Crosby, Daniel; Norton, Christopher J.

2016-11-22

A composition of matter includes water, at least one acid, at least one surfactant, at least one fluoride salt, and ammonium nitrate. A method of decontaminating a surface includes exposing a surface to such a composition and removing the composition from the surface. Other compositions of matter include water, a fatty alcohol ether sulfate, nitrilotriacetic acid, at least one of hydrochloric acid and nitric acid, sodium fluoride, potassium fluoride, ammonium nitrate, and gelatin.

SEPARATION OF URANIUM FROM ZIRCONIUM AND NIOBIUM BY SOLVENT EXTRACTION

DOEpatents

Voiland, E.E.

1958-05-01

A process for separation of the uranium from zirconium and/or niobium values contained in 3 to 7M aqueous nitric acid solutions is described. This is accomplished by adding phosphoric acid anions to the nitric acid solution containing the uranium, zirconium, and/or niobium in an amount sufficient to make the solution 0.05 to 0.2M in phosphate ion and contacting the solution with an organic water-immiscible solvent such as MEK, whereby the uranyl values are taken up by the extract phase while the zirconium and niobium preferentially remain in the aqueous raffinate.

Metastable Nitric Acid Trihydrate in Ice Clouds.

PubMed

Weiss, Fabian; Kubel, Frank; Gálvez, Óscar; Hoelzel, Markus; Parker, Stewart F; Baloh, Philipp; Iannarelli, Riccardo; Rossi, Michel J; Grothe, Hinrich

2016-03-01

The composition of high-altitude ice clouds is still a matter of intense discussion. The constituents in question are ice and nitric acid hydrates, but the exact phase composition of clouds and its formation mechanisms are still unknown. In this work, conclusive evidence for a long-predicted phase, alpha-nitric acid trihydrate (alpha-NAT), is presented. This phase was characterized by a combination of X-ray and neutron diffraction experiments, allowing a convincing structure solution. Furthermore, vibrational spectra (infrared and inelastic neutron scattering) were recorded and compared with theoretical calculations. A strong interaction between water ice and alpha-NAT was found, which explains the experimental spectra and the phase-transition kinetics. On the basis of these results, we propose a new three-step mechanism for NAT formation in high-altitude ice clouds. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Acid rain and sugar maple decline

Treesearch

Paul G. Schaberg

2017-01-01

Through the increased combustion of fossil fuels, humans have dramatically increased pollutant additions of sulfur and nitrogen into the atmosphere where it conbines with water to form sulfuric and nitric acids, creating acid rain (Driscoll et al. 2001). Incoming acid rain has various impacts on human and natural systems, including the accelerated degradation of built...

Copper ions removal from water using functionalized carbon nanotubes–mullite composite as adsorbent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tofighy, Maryam Ahmadzadeh; Mohammadi, Toraj, E-mail: torajmohammadi@iust.ac.ir

Highlights: • CNTs–mullite composite was prepared via chemical vapor deposition (CVD) method. • The prepared composite was modified with concentrated nitric acid and chitosan. • The modified CNTs–mullite composites were used as novel adsorbents. • Copper ion removal from water by the prepared adsorbents was performed. • Langmuir and Freundlich isotherms and two kinetic models were applied to fit the experimental data. - Abstract: Carbon nanotubes–mullite composite was synthesized by direct growth of carbon nanotubes on mullite particles via chemical vapor deposition method using cyclohexanol and ferrocene as carbon precursor and catalyst, respectively. The carbon nanotubes–mullite composite was oxidized withmore » concentrated nitric acid and functionalized with chitosan and then used as a novel adsorbent for copper ions removal from water. The results demonstrated that modification with concentrated nitric acid and chitosan improves copper ions adsorption capacity of the prepared composite, significantly. Langmuir and Freundlich isotherms and two kinetic models were applied to fit the experimental data. The carbon nanotubes growth on mullite particles to form the carbon nanotubes–mullite composite with further modification is an inherently safe approach for many promising environmental applications to avoid some concerns regarding environment, health and safety. It was found that the modified carbon nanotubes–mullite composite can be considered as an excellent adsorbent for copper ions removal from water.« less

Chemical treatment of commercial reverse osmosis membranes for use in FO

EPA Science Inventory

Commercially available reverse osmosis (RO) membranes – SW30HR, BW30, and AG – were chemically treated for use in forward osmosis (FO). Nitric acid, phosphoric acid, sulfuric acid, ethanol, and ethanol–acid–water ternary solutions were employed for the treatment. All three membra...

High frequency and large deposition of acid fog on high elevation forest.

PubMed

Igawa, Manabu; Matsumura, Ko; Okochi, Hiroshi

2002-01-01

We have collected and analyzed fogwater on the mountainside of Mt. Oyama (1252 m) in the Tanzawa Mountains of Japan and observed the fog event frequency from the base of the mountain with a video camera. The fog event frequency increased with elevation and was observed to be present 46% of the year at the summit. The water deposition via throughfall increased with elevation because of the increase in fogwater interception and was about twice that via rain at the summit, where the air pollutant deposition via throughfall was several times that via rainwater. The dry deposition and the deposition via fogwater were dominant factors in the total ion deposition at high elevation sites. In a fog event, nitric acid, the major acid component on the mountain, is formed during the transport of the air mass from the base of the mountain along the mountainside, where gases including nitric acid deposit and are scavenged by fogwater. Therefore, high acidity caused by nitric acid and relatively low ion strength are observed in the fogwater at high elevation sites.

URANIUM DECONTAMINATION WITH RESPECT TO ZIRCONIUM

DOEpatents

Vogler, S.; Beederman, M.

1961-05-01

A process is given for separating uranium values from a nitric acid aqueous solution containing uranyl values, zirconium values and tetravalent plutonium values. The process comprises contacting said solution with a substantially water-immiscible liquid organic solvent containing alkyl phosphate, separating an organic extract phase containing the uranium, zirconium, and tetravalent plutonium values from an aqueous raffinate, contacting said organic extract phase with an aqueous solution 2M to 7M in nitric acid and also containing an oxalate ion-containing substance, and separating a uranium- containing organic raffinate from aqueous zirconium- and plutonium-containing extract phase.

What Is Acid Rain?

ERIC Educational Resources Information Center

Likens, Gene E.

2004-01-01

Acid rain is the collective term for any type of acidified precipitation: rain, snow, sleet, and hail, as well as the presence of acidifying gases, particles, cloud water, and fog in the atmosphere. The increased acidity, primarily from sulfuric and nitric acids, is generated as a by-product of the combustion of fossil fuels such as coal and oil.…

Comparison of parameterized nitric acid rainout rates using a coupled stochastic-photochemical tropospheric model

NASA Technical Reports Server (NTRS)

Stewart, Richard W.; Thompson, Anne M.; Owens, Melody A.; Herwehe, Jerold A.

1989-01-01

A major tropospheric loss of soluble species such as nitric acid results from scavenging by water droplets. Several theoretical formulations have been advanced which relate an effective time-independent loss rate for soluble species to statistical properties of precipitation such as the wet fraction and length of a precipitation cycle. In this paper, various 'effective' loss rates that have been proposed are compared with the results of detailed time-dependent model calculations carried out over a seasonal time scale. The model is a stochastic precipitation model coupled to a tropospheric photochemical model. The results of numerous time-dependent seasonal model runs are used to derive numerical values for the nitric acid residence time for several assumed sets of preciptation statistics. These values are then compared with the results obtained by utilizing theoretical 'effective' loss rates in time-independent models.

Recovery of fission product palladium from acidic high level waste solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rizvi, G.H.; Mathur, J.N.; Murali, M.S.

1996-07-01

The recovery of palladium from a synthetic pressurized heavy water reactor high level waste (PHWR-HLW) solution has been carried out, and the best reagents to use for the actual HLW solutions are discussed. The extraction of palladium from nitric acid solutions has been carried out using Cyanex-471X (triisobutylphosphine sulfide, TIPS) as the extractant. The metal ion could be quantitatively extracted from solutions with nitric acid concentrations between 2.0 and 6.0 M. The species extracted into the organic phase was found to be Pd(NO{sub 3}){sub 2}{center_dot}TIPS. Nitric acid in the range of 2.0 to 5.0 M had no effect on TIPSmore » for at least 71 hours. A systematic study of gamma irradiation on loading and stripping of palladium from loaded organic phases using several potential extractants, TIPS, alpha benzoin oxime, dioctylsulfide, and dioctylsulfoxide has been made. A flow sheet for the recovery of palladium from actual HLW solutions using TIPS is proposed.« less

Recovery of gold from computer circuit board scrap using aqua regia.

PubMed

Sheng, Peter P; Etsell, Thomas H

2007-08-01

Computer circuit board scrap was first treated with one part concentrated nitric acid and two parts water at 70 degrees C for 1 h. This step dissolved the base metals, thereby liberating the chips from the boards. After solid-liquid separation, the chips, intermixed with some metallic flakes and tin oxide precipitate, were mechanically crushed to liberate the base and precious metals contained within the protective plastic or ceramic chip cases. The base metals in this crushed product were dissolved by leaching again with the same type of nitric acid-water solution. The remaining solid constituents, crushed chips and resin, plus solid particles of gold, were leached with aqua regia at various times and temperatures. Gold was precipitated from the leachate with ferrous sulphate.

Hydrogen-bonding interactions and protic equilibria in room-temperature ionic liquids containing crown ethers.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marin, T.; Shkrob, I.; Dietz, M.

2011-04-14

Nuclear magnetic resonance (NMR) spectroscopy has been used to study hydrogen-bonding interactions between water, associated and dissociated acids (i.e., nitric and methanesulfonic acids), and the constituent ions of several water-immiscible room-temperature ionic liquids (ILs). In chloroform solutions also containing a crown ether (CE), water molecules strongly associate with the IL ions, and there is rapid proton exchange between these bound water molecules and hydronium associated with the CE. In neat ILs, the acids form clusters differing in their degree of association and ionization, and their interactions with the CEs are weak. The CE can either promote proton exchange between differentmore » clusters in IL solution when their association is weak or inhibit such exchange when the association is strong. Even strongly hydrophobic ILs are shown to readily extract nitric acid from aqueous solution, typically via the formation of a 1:1:1 {l_brace}H{sub 3}O{sup +} {center_dot} CE{r_brace}NO{sub 3}{sup -} complex. In contrast, the extraction of methanesulfonic acid is less extensive and proceeds mainly by IL cation-hydronium ion exchange. The relationship of these protic equilibria to the practical application of hydrophobic ILs (e.g., in spent nuclear fuel reprocessing) is discussed.« less

Electrochemical Measurement of Atmospheric Corrosion

NASA Technical Reports Server (NTRS)

DeArmond, Anna H.; Davis, Dennis D.; Beeson, Harold D.

1999-01-01

Corrosion of Shuttle thruster components in atmospheres containing high concentrations of nitrogen tetroxide (NTO) and water is an important issue in ground operations of bipropellant systems in humid locations. Measurements of the corrosivities of NTO-containing atmospheres and the responses of different materials to these atmospheres have been accomplished using an electrochemical sensor. The sensor is composed of alternating aluminum/titanium strips separated by thin insulating layers. Under high humidity conditions a thin film of water covers the surface of the sensor. Added NTO vapor reacts with the water film to form a conductive medium and establishes a galvanic cell. The current from this cell can be integrated with respect to time and related to the corrosion activity. The surface layer formed from humid air/NTO reacts in the same way as an aqueous solution of nitric acid. Nitric acid is generally considered an important agent in NTO corrosion situations. The aluminum/titanium sensor is unresponsive to dry air, responds slightly to humid air (> 75% RH), and responds strongly to the combination of humid air and NTO. The sensor response is a power function (n = 2) of the NTO concentration. The sensor does not respond to NTO in dry air. The response of other materials in this type of sensor is related to position of the material in a galvanic series in aqueous nitric acid. The concept and operation of this electrochemical corrosion measurement is being applied to other corrosive atmospheric contaminants such as hydrogen chloride, hydrogen fluoride, sulfur dioxide, and acidic aerosols.

SOURCE ASSESSMENT: NITROGEN FERTILIZER INDUSTRY WATER EFFLUENTS

EPA Science Inventory

The report describes a study of waterborne pollutants from the manufacture of nitrogen fertilizers. It includes an evaluation of the ammonia, ammonium nitrate, urea, and nitric acid manufacturing processes. Water effluents in a nitrogen fertilizer plant originate from a variety o...

STIMULATION OF FUNDULUS BY HYDROCHLORIC AND FATTY ACIDS IN FRESH WATER, AND BY FATTY ACIDS, MINERAL ACIDS, AND THE SODIUM SALTS OF MINERAL ACIDS IN SEA WATER

PubMed Central

Allison, J. B.; Cole, William H.

1934-01-01

1. Fundulus heteroclitus was found to be a reliable experimental animal for studies on chemical stimulation in either fresh or sea water. 2. The response of Fundulus to hydrochloric, acetic, propionic, butyric, valeric, and caproic acids was determined in fresh water, while the same acids plus sulfuric and nitric, as well as the sodium salts of the mineral acids, were tested in sea water. 3. Stimulation of Fundulus by hydrochloric acid in fresh water is correlated with the effective hydrogen ion concentration. Stimulation by the n-aliphatic acids in the same environment is correlated with two factors, the effective hydrogen ion concentration and the potential of the non-polar group in the molecule. However, as the number of CH2 groups increases the stimulating effect increases by smaller and smaller amounts, approaching a maximum value. 4. Stimulation of Fundulus by hydrochloric, sulfuric, and nitric acids in sea water is correlated with the forces of primary valence which in turn are correlated with the change in hydrogen ion concentration of the sea water. The n-aliphatic acids increase in stimulating efficiency in sea water as the length of the carbon chain increases, but a limiting value is not reached as soon as in fresh water. 5. Only a slight difference in stimulation by hydrochloric acid is found in sea water and in fresh water. However, there is a significant difference in stimulation by the fatty acids in fresh and in sea water, which is partly explained by the different buffering capacities of the two media. It is to be noted that in the same environment two different fish, Fundulus and Eupomotis, give different results, while the same fish (Fundulus) in two different environments responds similarly to mineral acids but differently to fatty acids. These results illustrate that stimulation is a function of the interaction between environment and receptors, and that each is important in determining the response. 6. Stimulation by sodium chloride, nitrate, and sulfate is correlated with equivalent concentrations of the salts added to sea water, or with the forces of primary valence. Although the threshold for stimulation by the salts is considerably higher than for the acids, the efficiency of stimulation by the salts is greater. PMID:19872815

Attrition resistant gamma-alumina catalyst support

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singleton, Alan H.; Oukaci, Rachid; Goodwin, James G.

2006-03-14

A .gamma.-alumina catalyst support having improved attrition resistance produced by a method comprising the steps of treating a particulate .gamma.-alumina material with an acidic aqueous solution comprising water and nitric acid and then, prior to adding any catalytic material thereto, calcining the treated .gamma.-alumina.

Pretreatment Solution for Water Recovery Systems

NASA Technical Reports Server (NTRS)

Muirhead, Dean (Inventor)

2018-01-01

Chemical pretreatments are used to produce usable water by treating a water source with a chemical pretreatment that contains a hexavalent chromium and an acid to generate a treated water source, wherein the concentration of sulfate compounds in the acid is negligible, and wherein the treated water source remains substantially free of precipitates after the addition of the chemical pretreatment. Other methods include reducing the pH in urine to be distilled for potable water extraction by pretreating the urine before distillation with a pretreatment solution comprising one or more acid sources selected from a group consisting of phosphoric acid, hydrochloric acid, and nitric acid, wherein the urine remains substantially precipitate free after the addition of the pretreatment solution. Another method described comprises a process for reducing precipitation in urine to be processed for water extraction by mixing the urine with a pretreatment solution comprising hexavalent chromium compound and phosphoric acid.

Removal of Pb(II) from water by the activated carbon modified by nitric acid under microwave heating.

PubMed

Yao, Shuheng; Zhang, Jiajun; Shen, Dekui; Xiao, Rui; Gu, Sai; Zhao, Ming; Liang, Junyu

2016-02-01

The rice husk based activated carbon (RH-AC) was treated by nitric acid under microwave heating, in order to improve its capability for the removal of heavy metal ions from water. The optimal conditions for the modification of RH-AC (M-RH-AC) were determined by means of orthogonal array experimental design, giving those as the concentration of nitric acid of 8mol/L, modification time of 15min, modification temperature of 130°C and microwave power of 800W. The characteristics of the M-RH-AC and RH-AC were examined by BET, XRD, Raman spectrum, pH titration, zeta potential, Boehm titration and FTIR analysis. The M-RH-AC has lower pore surface area, smaller crystallite, lower pHIEP and more oxygen-containing functional groups than the RH-AC. Removal capacity of Pb(II) ions by the M-RH-AC and RH-AC from water solution was estimated concerning the influence of contact time, pH value, and initial concentration. The equilibrium time of Pb(II) removal was found to be around 90min after modification process. Two kinetic models are adopted to describe the possible Pb(II) adsorption mechanism, finding that the adsorption rate of Pb(II) ions by the M-RH-AC is larger than that of RH-AC. Copyright © 2015 Elsevier Inc. All rights reserved.

SEPARATION OF URANIUM, PLUTONIUM, AND FISSION PRODUCTS

DOEpatents

Spence, R.; Lister, M.W.

1958-12-16

Uranium and plutonium can be separated from neutron-lrradiated uranium by a process consisting of dissolvlng the lrradiated material in nitric acid, saturating the solution with a nitrate salt such as ammonium nitrate, rendering the solution substantially neutral with a base such as ammonia, adding a reducing agent such as hydroxylamine to change plutonium to the trivalent state, treating the solution with a substantially water immiscible organic solvent such as dibutoxy diethylether to selectively extract the uranium, maklng the residual aqueous solutlon acid with nitric acid, adding an oxidizing agent such as ammonlum bromate to oxidize the plutonium to the hexavalent state, and selectlvely extracting the plutonium by means of an immlscible solvent, such as dibutoxy dlethyletber.

METHOD OF ELECTROPLATING ON URANIUM

DOEpatents

Rebol, E.W.; Wehrmann, R.F.

1959-04-28

This patent relates to a preparation of metallic uranium surfaces for receiving coatings, particularly in order to secure adherent electroplated coatings upon uranium metal. In accordance with the invention the uranium surface is pretreated by degreasing in trichloroethylene, followed by immersion in 25 to 50% nitric acid for several minutes, and then rinsed with running water, prior to pickling in trichloroacetic acid. The last treatment is best accomplished by making the uranium the anode in an aqueous solution of 50 per cent by weight trichloroacetic acid until work-distorted crystals or oxide present on the metal surface have been removed and the basic crystalline structure of the base metal has been exposed. Following these initial steps the metallic uranium is rinsed in dilute nitric acid and then electroplated with nickel. Adnerent firmly-bonded coatings of nickel are obtained.

21 CFR 184.1095 - Sulfuric acid.

Code of Federal Regulations, 2011 CFR

2011-04-01

... CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific... (SO2) with oxygen and mixing the resultant sulfur trioxide (SO3) with water, or by reacting nitric...

21 CFR 184.1095 - Sulfuric acid.

Code of Federal Regulations, 2013 CFR

2013-04-01

... CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific... (SO2) with oxygen and mixing the resultant sulfur trioxide (SO3) with water, or by reacting nitric...

Nitric acid uptake by sulfuric acid solutions under stratospheric conditions - Determination of Henry's Law solubility

NASA Technical Reports Server (NTRS)

Reihs, Christa M.; Golden, David M.; Tolbert, Margaret A.

1990-01-01

The uptake of nitric acid by sulfuric acid solutions representative of stratospheric particulate at low temperatures was measured to determine the solubility of nitric acid in sulfuric acid solutions as a function of H2SO4 concentration and solution temperature. Solubilities are reported for sulfuric acid solutions ranging from 58 to 87 wt pct H2SO4 over a temperature range from 188 to 240 K, showing that, in general, the solubility of nitric acid increases with decreasing sulfuric acid concentration and with decreasing temperature. The measured solubilities indicate that nitric acid in the global stratosphere will be found predominantly in the gas phase.

Comparison of Four Strong Acids on the Precipitation Potential of Gypsum in Brines During Distillation of Pretreated, Augmented Urine

NASA Technical Reports Server (NTRS)

Muirhead, Dean

2011-01-01

Two batches of nominally pretreated and augmented urine were prepared with the baseline pretreatment formulation of sulfuric acid and chromium trioxide. The urine was augmented with inorganic salts and organic compounds in order to simulate a urinary ionic concentrations representing the upper 95 percentile on orbit. Three strong mineral acids: phosphoric, hydrochloric, and nitric acid, were substituted for the sulfuric acid for comparison to the baseline sulfuric acid pretreatment formulation. Three concentrations of oxidizer in the pretreatment formulation were also tested. Pretreated urine was distilled to 85% water recovery to determine the effect of each acid and its conjugate base on the precipitation of minerals during distillation. The brines were analyzed for calcium and sulfate ion, total, volatile, and fixed suspended solids. Test results verified that substitution of phosphoric, hydrochloric, or nitric acids for sulfuric acid would prevent the precipitation of gypsum up to 85% recovery from pretreated urine representing the upper 95 percentile calcium concentration on orbit.

Fine particle pH and gas-particle phase partitioning of inorganic species in Pasadena, California, during the 2010 CalNex campaign

NASA Astrophysics Data System (ADS)

Guo, Hongyu; Liu, Jiumeng; Froyd, Karl D.; Roberts, James M.; Veres, Patrick R.; Hayes, Patrick L.; Jimenez, Jose L.; Nenes, Athanasios; Weber, Rodney J.

2017-05-01

pH is a fundamental aerosol property that affects ambient particle concentration and composition, linking pH to all aerosol environmental impacts. Here, PM1 and PM2. 5 pH are calculated based on data from measurements during the California Research at the Nexus of Air Quality and Climate Change (CalNex) study from 15 May to 15 June 2010 in Pasadena, CA. Particle pH and water were predicted with the ISORROPIA-II thermodynamic model and validated by comparing predicted to measured gas-particle partitioning of inorganic nitrate, ammonium, and chloride. The study mean ± standard deviation PM1 pH was 1.9 ± 0.5 for the SO42--NO3--NH4+-HNO3-NH3 system. For PM2. 5, internal mixing of sea salt components (SO42--NO3--NH4+-Na+-Cl--K+-HNO3-NH3-HCl system) raised the bulk pH to 2.7 ± 0.3 and improved predicted nitric acid partitioning with PM2. 5 components. The results show little effect of sea salt on PM1 pH, but significant effects on PM2. 5 pH. A mean PM1 pH of 1.9 at Pasadena was approximately one unit higher than what we have reported in the southeastern US, despite similar temperature, relative humidity, and sulfate ranges, and is due to higher total nitrate concentrations (nitric acid plus nitrate) relative to sulfate, a situation where particle water is affected by semi-volatile nitrate concentrations. Under these conditions nitric acid partitioning can further promote nitrate formation by increasing aerosol water, which raises pH by dilution, further increasing nitric acid partitioning and resulting in a significant increase in fine particle nitrate and pH. This study provides insights into the complex interactions between particle pH and nitrate in a summertime coastal environment and a contrast to recently reported pH in the eastern US in summer and winter and the eastern Mediterranean. All studies have consistently found highly acidic PM1 with pH generally below 3.

Fourier spectroscopy of the stratospheric emission

NASA Technical Reports Server (NTRS)

Carli, B.; Mencaraglia, F.; Bonetti, A.

1980-01-01

Stratospheric emission spectra in the submillimeter range have been recorded with a resolution of 0.0033/cm with a balloon-borne interferometer. Several minor atmospheric constituents have been identified in a preliminary analysis of the spectra; these are water vapor, oxygen, ozone isotopes, nitric acid, nitrous oxide, hydrofluoric and hydrochloric acids, and carbon monoxide.

Citric Acid Passivation of Stainless Steel

NASA Technical Reports Server (NTRS)

Yasensky, David; Reali, John; Larson, Chris; Carl, Chad

2009-01-01

Passivation is a process for cleaning and providing corrosion protection for stainless steel. Currently, on Kennedy Space Center (KSC), only parts passivated with nitric acid are acceptable for use. KSC disposes of approximately 125gal of concentrated nitric acid per year, and receives many parts from vendors who must also dispose of used nitric acid. Unfortunately, nitric acid presents health and environmental hazards. As a result, several recent industry studies have examined citric acid as an alternative. Implementing a citric acid-based passivation procedure would improve the health and environmental safety aspects of passivation process. However although there is a lack of published studies that conclusively prove citric acid is a technically sound passivation agent. In 2007, NASA's KSC Materials Advisory Working Group requested the evaluation of citric acid in place of nitric acid for passivation of parts at KSC. United Space Alliance Materials & Processes engineers have developed a three-phase test plan to evaluate citric acid as an alternative to nitric acid on three stainless steels commonly used at KSC: UNS S30400, S41000, and S17400. Phases 1 and 2 will produce an optimized citric acid treatment based on results from atmospheric exposure at NASA's Beach Corrosion Facility. Phase 3 will compare the optimized solution(s) with nitric acid treatments. If the results indicate that citric acid passivates as well or better than nitric acid, NASA intends to approve this method for parts used at the Kennedy Space Center.

Hydroxycarboxylic acids and salts

DOEpatents

Kiely, Donald E; Hash, Kirk R; Kramer-Presta, Kylie; Smith, Tyler N

2015-02-24

Compositions which inhibit corrosion and alter the physical properties of concrete (admixtures) are prepared from salt mixtures of hydroxycarboxylic acids, carboxylic acids, and nitric acid. The salt mixtures are prepared by neutralizing acid product mixtures from the oxidation of polyols using nitric acid and oxygen as the oxidizing agents. Nitric acid is removed from the hydroxycarboxylic acids by evaporation and diffusion dialysis.

Structural and technological characterisation of pectin extracted with sodium citrate and nitric acid from sunflower heads.

PubMed

Muñoz-Almagro, Nerea; Rico-Rodriguez, Fabián; Wilde, Peter J; Montilla, Antonia; Villamiel, Mar

2018-05-18

An optimisation of temperature, time and extracting agent concentration of pectin extraction from sunflower heads using sodium citrate and nitric acid (SP-SC and SP-NA) was carried out. At optimal conditions, the yield of extraction with nitric acid (SPO-NA) was 2-fold greater than the corresponding with sodium citrate (SPO-SC) (14.3 vs 7.7%, respectively). Regarding pectin structure, the galacturonic acid (GalA) content in both, SPO-SC and SPO-NA, was similar (∼85%). However, SPO-NA showed lower molecular weight (Mw) (88.9 kDa) and neutral sugar content (4%) than SPO-SC (464 kDa, 9%), indicating that nitric acid deeply degraded pectin structure. These differences derived into dissimilar behaviour in their technological functionality. SPO-SC showed higher viscosity and better emulsifying capacity than SPO-NA, although any of them were able to stabilise the oil/water emulsion. Both sunflower pectins formed gels with Ca 2+ (75 mg/g of pectin) at pH 3.0. However, when sucrose was added, the gels formed by SP-SC and 20% sucrose presented the same hardness as those of SP-NA with 40% sucrose. These results suggest that the pectin extracted with sodium citrate, an eco-friendly agent, could be a promising ingredient, with good thickening and gelling properties. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

40 CFR 141.86 - Monitoring requirements for lead and copper in tap water.

Code of Federal Regulations, 2011 CFR

2011-07-01

... procedures specified in this paragraph. To avoid problems of residents handling nitric acid, acidification of... no plastic pipes which contain lead plasticizers, or plastic service lines which contain lead...

40 CFR 141.86 - Monitoring requirements for lead and copper in tap water.

Code of Federal Regulations, 2010 CFR

2010-07-01

... procedures specified in this paragraph. To avoid problems of residents handling nitric acid, acidification of... no plastic pipes which contain lead plasticizers, or plastic service lines which contain lead...

REDUCTION OF ACIDITY OF NITRIC ACID SOLUTIONS BY USE OF FORMALDEHYDE

DOEpatents

Healy, T.V.

1958-05-20

A continuous method is described of concentrating by evaporation and reducing the nitrate ion content of an aqueous solution of metallic salts containing nitric acid not in excess of 8N. It consists of heating the solution and then passing formaldehyde into the heated solution to bring about decomposition of the nitric acid. The evolved gases containing NO are contacted countercurrently with an aqueous metal salt solution containing nitric acid in excess of 8N so as to bring about decomposition of the nitric acid and lower the normality to at least 8N, whereupon it is passed into the body of heated solution.

Determining gold in water by anion-exchange batch extraction

USGS Publications Warehouse

McHugh, J.B.

1986-01-01

This paper describes a batch procedure for determining gold in natural waters. It is completely adaptable to field operations. The water samples are filtered and acidified before they are equilibrated with an anion-exchange resin by shaking. The gold is then eluted with acetone-nitric acid solution, and the eluate evaporated to dryness. The residue is taken up in hydrobromic acid-bromine solution and the gold is extracted with methyl isobutyl ketone. The extract is electrothermally atomized in an atomic-absorption spectrophotometer. The limit of determination is 1 ng 1. ?? 1986.

Experimental and Quantum Mechanics Investigations of Early Reactions of Monomethylhydrazine with Mixtures of NO2 and N2O4

DTIC Science & Technology

2013-02-15

red fuming nitric acid (RFNA), which is composed of nitric acid (HNO3, 85 wt%) and NO2 (8–15 wt%). Recently the impinging stream vortex engine (ISVE... nitric acid [51]. As a result, growth of the particles is favored over H-abstraction reactions at the low temperatures of our experiments. As the...followed by the proton transfer from NAH bond to NO3 to form nitric acid , as shown in Scheme 3. Although it is very easy to form nitric acid (enthalpic

Image analysis of epicuticular damage to foliage caused by dry deposition of the air pollutant nitric acid

Treesearch

Pamela E. Padgett; Sally D. Parry; Andrzej Bytnerowicz; Robert L. Heath

2009-01-01

Nitric acid vapor is produced by the same photochemical processes that produce ozone. In the laboratory, concentrated nitric acid is a strong acid and a powerful oxidant. In the environment, where the concentrations are much lower, it is an innocuous source of plant nitrogen. As an air pollutant, which mode of action does dry deposition of nitric...

METHOD OF RECOVERING THORIUM

DOEpatents

Fisher, R.W.

1957-12-10

A method is described for recovering thorium from impurities found in a slag containing thorium and said impurities, comprising leaching a composition containing thorium with water, removing the water solution, treating the residue with hydrochloric acid, separating the solution from the insoluble residue, adjusting its acidity to 1 to 3 normal, adding oxalic acid, and thereafter separating the precipitated thorium oxalate digesting the residue from the hydrochloric acid treatment with a strong solution of sodium hydroxide at an elevated temperature, removing said solution and treating the insoluble residue with hydrochloric acid, separating the solution from the insoluble residue, adjusting the acidity of this solution to 1 to 3 normal, adding nitric acid to oxidize the iron present, adding oxalic acid and thereafter separating the thorium oxalate thus precipitated.

NITRIC ACID RECPVERY FROM WASTE COLUTIONS

DOEpatents

Wilson, A.S.

1959-04-14

The recovery of nitric acid from aqueous nitrate solutions containing fission products as impurities is described. It is desirable to subject such solutions to concentration by evaporation since nitric acid is regenerated thereby. A difficulty, however, is that the highly radioactive fission product ruthenium is volatilized together with the nitric acid. It has been found that by adding nitrous acids ruthenium volatilization is suppressed and reduced to a negligible degree so that the distillate obtained is practically free of rutheniuim.

Nitric acid recovery from waste solutions

DOEpatents

Wilson, A. S.

1959-04-14

The recovery of nitric acid from aqueous nitrate solutions containing fission products as impurities is described. It is desirable to subject such solutions to concentration by evaporation since nitric acid is regenerated thereby. A difficulty, however, is that the highly radioactive fission product ruthenium is volatilized together with the nitric acid. It has been found that by adding nitrous acid, ruthenium volatilization is suppressed and reduced to a negligible degree so that the distillate obtained is practically free of ruthenium.

PROCESS OF RECOVERING ZIRCONIUM VALUES FROM HAFNIUM VALUES BY SOLVENT EXTRACTION WITH AN ALKYL PHOSPHATE

DOEpatents

Peppard, D.F.

1960-02-01

A process of separating hafnium nitrate from zirconium nitrate contained in a nitric acid solution by selectively. extracting the zirconium nitrate with a water-immiscible alkyl phosphate is reported.

Mercury-free dissolution of aluminum-clad fuel in nitric acid

DOEpatents

Christian, Jerry D.; Anderson, Philip A.

1994-01-01

A mercury-free dissolution process for aluminum involves placing the aluminum in a dissolver vessel in contact with nitric acid-fluoboric acid mixture at an elevated temperature. By maintaining a continuous flow of the acid mixture through the dissolver vessel, an effluent containing aluminum nitrate, nitric acid, fluoboric acid and other dissolved components are removed.

Mercury-free dissolution of aluminum-clad fuel in nitric acid

DOEpatents

Christian, J.D.; Anderson, P.A.

1994-11-15

A mercury-free dissolution process for aluminum involves placing the aluminum in a dissolver vessel in contact with nitric acid-fluoboric acid mixture at an elevated temperature. By maintaining a continuous flow of the acid mixture through the dissolver vessel, an effluent containing aluminum nitrate, nitric acid, fluoboric acid and other dissolved components are removed. 5 figs.

Development of Reactive Topical Skin Protectants against Sulfur Mustard and Nerve Agents

DTIC Science & Technology

1997-06-01

Inorganic pollutants such as hydrogen cyanide, cyanogen chloride, and acid gases are not adsorbed well by activated carbon, and (3) Clean-up and...with Fe203 caused an increase in destructive adsorbent capacity of chlorocarbons, acid gases, and organophosphorus compounds. We attribute this...solution of distilled water, concentrated nitric acid , and methanol were added to methanol and neat titanium (IV) butoxide. The formed gel was aged

Wintertime water-soluble aerosol composition and particle water content in Fresno, California

NASA Astrophysics Data System (ADS)

Parworth, Caroline L.; Young, Dominique E.; Kim, Hwajin; Zhang, Xiaolu; Cappa, Christopher D.; Collier, Sonya; Zhang, Qi

2017-03-01

The composition and concentrations of water-soluble gases and ionic aerosol components were measured from January to February 2013 in Fresno, CA, with a particle-into-liquid sampler with ion chromatography and annular denuders. The average (±1σ) ionic aerosol mass concentration was 15.0 (±9.4) µg m-3, and dominated by nitrate (61%), followed by ammonium, sulfate, chloride, potassium, nitrite, and sodium. Aerosol-phase organic acids, including formate and glycolate, and amines including methylaminium, triethanolaminium, ethanolaminium, dimethylaminium, and ethylaminium were also detected. Although the dominant species all came from secondary aerosol formation, there were primary sources of ionic aerosols as well, including biomass burning for potassium and glycolate, sea spray for sodium, chloride, and dimethylamine, and vehicles for formate. Particulate methanesulfonic acid was also detected and mainly associated with terrestrial sources. On average, the molar concentration of ammonia was 49 times greater than nitric acid, indicating that ammonium nitrate formation was limited by nitric acid availability. Particle water was calculated based on the Extended Aerosol Inorganics Model (E-AIM) thermodynamic prediction of inorganic particle water and κ-Köhler theory approximation of organic particle water. The average (±1σ) particle water concentration was 19.2 (±18.6) µg m-3, of which 90% was attributed to inorganic species. The fractional contribution of particle water to total fine particle mass averaged at 36% during this study and was greatest during early morning and night and least during the day. Based on aqueous-phase concentrations of ions calculated by using E-AIM, the average (±1σ) pH of particles in Fresno during the winter was estimated to be 4.2 (±0.2).

Infrared optical constants of H2O ice, amorphous nitric acid solutions, and nitric acid hydrates

NASA Technical Reports Server (NTRS)

Toon, Owen B.; Koehler, Birgit G.; Middlebrook, Ann M.; Tolbert, Margaret A.; Jordon, Joseph

1994-01-01

We determined the infrared optical constants of nitric acid trihydrate, nitric acid dihydrate, nitric acid monohydrate, and solid amorphous nitric acid solutions which crystallize to form these hydrates. We have also found the infrared optical constants of H2O ice. We measured the transmission of infrared light throught thin films of varying thickness over the frequency range from about 7000 to 500/cm at temperatures below 200 K. We developed a theory for the transmission of light through a substrate that has thin films on both sides. We used an iterative Kramers-Kronig technique to determine the optical constants which gave the best match between measured transmission spectra and those calculated for a variety of films of different thickness. These optical constants should be useful for calculations of the infrared spectrum of polar stratospheric clouds.

Reactions Between Water Soluble Organic Acids and Nitrates in Atmospheric Aerosols: Recycling of Nitric Acid and Formation of Organic Salts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Bingbing; Laskin, Alexander

Atmospheric particles often include a complex mixture of nitrate and secondary organic materials accumulated within the same individual particles. Nitrate as an important inorganic component can be chemically formed in the atmosphere. For instance, formation of sodium nitrate (NaNO3) and calcium nitrate Ca(NO3)2 when nitrogen oxide and nitric acid (HNO3) species react with sea salt and calcite, respectively. Organic acids contribute a significant fraction of photochemically formed secondary organics that can condense on the preexisting nitrate-containing particles. Here, we present a systematic microanalysis study on chemical composition of laboratory generated particles composed of water soluble organic acids and nitrates (i.e.more » NaNO3 and Ca(NO3)2) investigated using computer controlled scanning electron microscopy with energy dispersive analysis of X-rays (CCSEM/EDX) and Fourier transform infrared micro-spectroscopy (micro-FTIR). The results show that water-soluble organic acids can react with nitrates releasing gaseous HNO3 during dehydration process. These reactions are attributed to acid displacement of nitrate with weak organic acids driven by the evaporation of HNO3 into gas phase due to its relatively high volatility. The reactions result in significant nitrate depletion and formation of organic salts in mixed organic acids/nitrate particles that in turn may affect their physical and chemical properties relevant to atmospheric environment and climate. Airborne nitrate concentrations are estimated by thermodynamic calculations corresponding to various nitrate depletions in selected organic acids of atmospheric relevance. The results indicate a potential mechanism of HNO3 recycling, which may further affect concentrations of gas- and aerosol-phase species in the atmosphere and the heterogeneous reaction chemistry between them.« less

A FURTHER EVALUATION OF MICROCOULOMETRY FOR ATMOSPHERIC NITRIC ACID MONITORING

EPA Science Inventory

A coulometric instrument for measuring gaseous nitric acid is modified to improve response time characteristics and simplify operation. Possible interferences were investigated and found minimal. Comparison measurements of nitric acid by long path Fourier Transform infrared analy...

Alternative Chemical Cleaning Methods for High Level Waste Tanks: Actual Waste Testing with SRS Tank 5F Sludge

DOE Office of Scientific and Technical Information (OSTI.GOV)

King, William D.; Hay, Michael S.

Solubility testing with actual High Level Waste tank sludge has been conducted in order to evaluate several alternative chemical cleaning technologies for the dissolution of sludge residuals remaining in the tanks after the exhaustion of mechanical cleaning and sludge sluicing efforts. Tests were conducted with archived Savannah River Site (SRS) radioactive sludge solids that had been retrieved from Tank 5F in order to determine the effectiveness of an optimized, dilute oxalic/nitric acid cleaning reagent toward dissolving the bulk non-radioactive waste components. Solubility tests were performed by direct sludge contact with the oxalic/nitric acid reagent and with sludge that had beenmore » pretreated and acidified with dilute nitric acid. For comparison purposes, separate samples were also contacted with pure, concentrated oxalic acid following current baseline tank chemical cleaning methods. One goal of testing with the optimized reagent was to compare the total amounts of oxalic acid and water required for sludge dissolution using the baseline and optimized cleaning methods. A second objective was to compare the two methods with regard to the dissolution of actinide species known to be drivers for SRS tank closure Performance Assessments (PA). Additionally, solubility tests were conducted with Tank 5 sludge using acidic and caustic permanganate-based methods focused on the “targeted” dissolution of actinide species.« less

Reference Book for the Nitrogen Industry Worker. Volume II,

DTIC Science & Technology

1982-03-19

of concentrated nitric acid , oxygen is one of the main reagents. Oxygen is generally used which was obtained by the ... nitric acid . The power used for compres- sion of the gases is recuperatred by 30-40% in the turbine that sits on the common shaft with the air... of nitric oxides from nitrous gases by concntatd nitric acid . This method

Separation of thorium and uranium in nitric acid solution using silica based anion exchange resin.

PubMed

Chen, Yanliang; Wei, Yuezhou; He, Linfeng; Tang, Fangdong

2016-09-30

To separate thorium and uranium in nitric acid solution using anion exchange process, a strong base silica-based anion exchange resin (SiPyR-N4) was synthesized. Batch experiments were conducted and the separation factor of thorium and uranium in 9M nitric acid was about 10. Ion exchange chromatography was applied to separate thorium and uranium in different ratios. Uranium could be eluted by 9M nitric acid and thorium was eluted by 0.1M nitric acid. It was proved that thorium and uranium can be separated and recovered successfully by this method. Copyright © 2016 Elsevier B.V. All rights reserved.

METHOD 200.5 - DETERMINATION OF TRACE ELEMENTS IN DRINKING WATER BY AXIALLY VIEWED INDUCTIVELY COUPLED PLASMA-ATOMIC EMISSION SPECTROMETRY

EPA Science Inventory

2.0 SUMMARY OF METHOD
2.1. A 50 mL aliquot of a well-mixed, non-filtered, acid preserved aqueous sample is accurately transferred to clean 50-mL plastic disposable digestion tube containing a mixture of nitric and hydrochloric acids. The aliquot is heated to 95 degrees C (+ o...

The Oxidative Stability of Deuterated Lubricants

DTIC Science & Technology

1982-01-01

through the fluid at some elevated temperature Iand following the increase of viscosity, acidity , or peroxide concentration with time, or monitoring the...1to use, the cells were cleaned in a hot nitric/sulfuric acid bath, rinsed repeatedly with distilled water, and baked overnight in an oven. All sample J...detection), and acidity (by base titration). The gas evolution rate of the lubricant was measured continuously with the gas sensor and displayed on a

Development of Electrically Conductive Transparent Coatings for Acrylic Plastic

DTIC Science & Technology

1952-12-01

after drying, but increased to 4,000 megoihms/square after 16 hours. 4. Polyacrylic-polyamine Cop-lyrrvrs Aqueous solutions of polymethacrylic acid ...methacrylic acid -methyl methaerylate copolymer re•I. The composite material, i. e., the acrylic and applied coating, retains essentially all the original...ation in 5%, NaOH solution for 5 minutes, rinsed in distilled water, immersed with agitation in 1516 nitric acid for 3 minutes and finally rinsed well

SOLVENT EXTRACTION OF THORIUM VALUES FROM AQUEOUS SOLUTIONS

DOEpatents

Warf, J.C.

1959-04-21

The separation of thorium values from rare earth metals contained ln aqueous solutions by means of extraction with a water immiscible alkyl phosphate diluted with a hydrocarbon such as hexane is described. While the extraction according to this invention may be carried out from any aqueous salt solution, it is preferred to use solutions containing free mineral acid. Hydrochloric acid and in particular nitric acid are sultable in a concentration ranging from 0.1 to 7 normal. The higher acid concentration results in higher extraction values.

Preservation of samples for dissolved mercury

USGS Publications Warehouse

Hamlin, S.N.

1989-01-01

Water samples for dissolved mercury requires special treatment because of the high chemical mobility and volatility of this element. Widespread use of mercury and its compounds has provided many avenues for contamination of water. Two laboratory tests were done to determine the relative permeabilities of glass and plastic sample bottles to mercury vapor. Plastic containers were confirmed to be quite permeable to airborne mercury, glass containers were virtually impermeable. Methods of preservation include the use of various combinations of acids, oxidants, and complexing agents. The combination of nitric acid and potassium dichromate successfully preserved mercury in a large variety of concentrations and dissolved forms. Because this acid-oxidant preservative acts as a sink for airborne mercury and plastic containers are permeable to mercury vapor, glass bottles are preferred for sample collection. To maintain a healthy work environment and minimize the potential for contamination of water samples, mercury and its compounds are isolated from the atmosphere while in storage. Concurrently, a program to monitor environmental levels of mercury vapor in areas of potential contamination is needed to define the extent of mercury contamination and to assess the effectiveness of mercury clean-up procedures.Water samples for dissolved mercury require special treatment because of the high chemical mobility and volatility of this element. Widespread use of mercury and its compounds has provided many avenues for contamination of water. Two laboratory tests were done to determine the relative permeabilities of glass and plastic sample bottles to mercury vapor. Plastic containers were confirmed to be quite permeable to airborne mercury, glass containers were virtually impermeable. Methods of preservation include the use of various combinations of acids, oxidants, and complexing agents. The combination of nitric acid and potassium dichromate successfully preserved mercury in a large variety of concentrations and dissolved forms.

Thermophysical Properties of Energetic Ionic Liquids/Nitric Acid Mixtures: Insights from Molecular Dynamics Simulations

DTIC Science & Technology

2013-01-01

W L. Physical properties of concentrated nitric acid . UNT Digital Library. http://digital.library.unt.edu/ark:/67531/metadc56640/.) 23 M. Engelmann... Nitric Acid Mixtures: Insights from Molecular Dynamics Simulations 5a. CONTRACT NUMBER FA9300-11-C-3012 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER...Rev. 8-98) Prescribed by ANSI Std. 239.18 1     Thermophysical  Properties  of  Energetic  Ionic  Liquids/ Nitric   Acid

40 CFR 418.50 - Applicability; description of the nitric acid subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 30 2012-07-01 2012-07-01 false Applicability; description of the nitric acid subcategory. 418.50 Section 418.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Nitric Acid...

40 CFR 418.50 - Applicability; description of the nitric acid subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 29 2014-07-01 2012-07-01 true Applicability; description of the nitric acid subcategory. 418.50 Section 418.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Nitric Acid...

40 CFR 418.50 - Applicability; description of the nitric acid subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 30 2013-07-01 2012-07-01 true Applicability; description of the nitric acid subcategory. 418.50 Section 418.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Nitric Acid...

40 CFR 418.50 - Applicability; description of the nitric acid subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 28 2010-07-01 2010-07-01 true Applicability; description of the nitric acid subcategory. 418.50 Section 418.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Nitric Acid...

40 CFR 418.50 - Applicability; description of the nitric acid subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 29 2011-07-01 2009-07-01 true Applicability; description of the nitric acid subcategory. 418.50 Section 418.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Nitric Acid...

Nitric acid in polar stratospheric clouds - Similar temperature of nitric acid condensation and cloud formation

NASA Technical Reports Server (NTRS)

Pueschel, Rudolf F.; Snetsinger, Kenneth G.; Hamill, Patrick; Goodman, Jindra K.; Mccormick, M. Patrick

1990-01-01

As shown independently by two different techniques, nitric acid aerosols and polar stratospheric clouds (PSCs) both form below similar threshold temperatures. This supports the idea that the PSC particles involved in chlorine activation and ozone depletion in the winter polar stratosphere are composed of nitric acid. One technique used to show this is the inertial impaction of nitric acid aerosols using an Er-2 aircraft; the other method is remote sensing of PSCs by the Stratospheric Aerosol Measurement (SAM II) satellite borne optical sensor. Both procedures were in operation during the Arctic Airborne Stratospheric Expedition in 1989, and the Airborne Antarctic Ozone Experiment in 1987. Analysis of Arctic particles gathered in situ indicates the presence of nitric acid below a 'first appearance' temperature Tfa = 202 K. This is the same highest temperature at which PSCs are seen by the SAM II satellite. In comparison, a 'first appearance' temperature Tfa = 198 K as found for the Antarctic samples.

Formation of model polar stratospheric cloud films

NASA Technical Reports Server (NTRS)

Middlebrook, Ann M.; Koehler, Birgit G.; Mcneill, Laurie S.; Tolbert, Margaret A.

1992-01-01

Fourier transform infrared spectroscopy was used to examine the competitive growth of films representative of polar stratospheric clouds. These experiments show that either crystalline nitric acid trihydrate (beta-NAT) or amorphous films with H2O:HNO3 ratios close to 3:1 formed at temperatures 3-7 K warmer than the ice frost point under stratospheric pressure conditions. In addition, with higher HNO3 pressure, we observed nitric acid dihydrate (NAD) formation at temperatures warmer than ice formation. However, our experiments also show that NAD surfaces converted to beta-NAT upon exposure to stratospheric water pressures. Finally, we determined that the net uptake coefficient for HNO3 on beta-NAT is close to unity, whereas the net uptake coefficient for H2O is much less.

Simultaneous generation of acidic and alkaline water using atmospheric air plasma formed in water

NASA Astrophysics Data System (ADS)

Imai, Shin-ichi; Sakaguchi, Yoshihiro; Shirafuji, Tatsuru

2018-01-01

Plasmas on water surfaces and in water can be generated at atmosphere pressure using several kinds of gases, including helium, argon, oxygen, and air. Nitrates are generated in water through the interaction between water and atmospheric plasma that uses ambient air. Water that has been made acidic by the generation of nitric acid and the acidic water can be used for the sterilization of medical instruments, toilet bowls, and washing machines. Dishwashers are another potential application, as alkaline water is needed to remove grease from tableware. To investigate the production of alkaline water and its mechanism, gas component analysis was performed using an atmospheric quadrupole mass spectrometer. It was found that hydrogen gas evolves from the water surrounding both the positive and negative electrodes. The gas and water analyses carried out in this study revealed that acidic water of pH 2.5 and alkaline water of pH 10 can be simultaneously generated by our ambient air plasma device, which has been altered from our original model. The alterative plasma device has a partition wall, which is made of conductive resin, between the positive and negative electrodes.

Laboratory scale Clean-In-Place (CIP) studies on the effectiveness of different caustic and acid wash steps on the removal of dairy biofilms.

PubMed

Bremer, Philip J; Fillery, Suzanne; McQuillan, A James

2006-02-15

A laboratory scale, bench top flow system was used to partially reproduce dairy plant conditions under which biofilms form and to quantify the effectiveness of caustic and acid wash steps in reducing the number of viable bacteria attached to stainless steel (SS) surfaces. Once bacteria attached to surfaces, a standard clean-in-place (CIP) regime (water rinse, 1% sodium hydroxide at 65 degrees C for 10 min, water rinse, 1.0% nitric acid at 65 degrees C for 10 min, water rinse) did not reproducibly ensure their removal. Standard CIP effectiveness was compared to alternative cleaning chemicals such as: caustic blends (Alkazolv 48, Ultrazolv 700, Concept C20, and Reflex B165); a caustic additive (Eliminator); acid blends (Nitroplus and Nitrobrite); and sanitizer (Perform). The addition of a caustic additive, Eliminator, enhanced biofilm removal compared to the standard CIP regime and further increases in cleaning efficiency occurred when nitric acid was substituted with Nitroplus. The combination of NaOH plus Eliminator and Nitroplus achieved a 3.8 log reduction in the number of cells recovered from the stainless steel surface. The incorporation of a sanitizer step into the CIP did not appear to enhance biofilm removal. This study has shown that the effectiveness of a "standard" CIP can possibly be enhanced through the testing and use of caustic and acid blends. There are many implications of these findings, including: the development of improved cleaning regimes and improved product quality, plant performance, and economic returns.

Inhibitory effects of indole α-lipoic acid derivatives on nitric oxide production in LPS/IFNγ activated RAW 264.7 macrophages.

PubMed

Karabay, Arzu Zeynep; Koc, Aslı; Gurkan-Alp, A Selen; Buyukbingol, Zeliha; Buyukbingol, Erdem

2015-04-01

Alpha-lipoic acid (α-lipoic acid) is a potent antioxidant compound that has been shown to possess anti-inflammatory effects. RAW 264.7 macrophages produce various inflammatory mediators such as nitric oxide, IL-1β, IL-6 and TNF-alpha upon activation with LPS (Lipopolysaccharide) and IFNγ (interferon gamma). In this study, the effect of 12 synthetic indole α-lipoic acid derivatives on nitric oxide production and iNOS (inducible nitric oxide synthase) protein expression in LPS/IFNγ activated RAW 264.7 macrophages was determined. Cell proliferation, nitric oxide levels and iNOS protein expression were examined with thiazolyl blue tetrazolium blue test, griess assay and western blot, respectively. Our results showed that all of the indole α-lipoic acid derivatives showed significant inhibitory effects on nitric oxide production and iNOS protein levels (p < 0.05). The most active compounds were identified as compound I-4b, I-4e and II-3b. In conclusion, these indole α-lipoic acid derivatives may have the potential for treatment of inflammatory conditions related with high nitric oxide production. Copyright © 2015 John Wiley & Sons, Ltd.

40 CFR 98.223 - Calculating GHG emissions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Nitric Acid Production § 98.223 Calculating GHG emissions. (a) You must determine annual N2O process emissions from each nitric acid train according to paragraphs (a...) You must conduct an annual performance test for each nitric acid train according to paragraphs (b)(1...

40 CFR 98.223 - Calculating GHG emissions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Nitric Acid Production § 98.223 Calculating GHG emissions. (a) You must determine annual N2O process emissions from each nitric acid train according to paragraphs (a...) You must conduct an annual performance test for each nitric acid train according to paragraphs (b)(1...

40 CFR 98.223 - Calculating GHG emissions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Nitric Acid Production § 98.223 Calculating GHG emissions. (a) You must determine annual N2O process emissions from each nitric acid train according to paragraphs (a...) You must conduct an annual performance test for each nitric acid train according to paragraphs (b)(1...

40 CFR 98.223 - Calculating GHG emissions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Nitric Acid Production § 98.223 Calculating GHG emissions. (a) You must determine annual N2O process emissions from each nitric acid train according to paragraphs (a...) You must conduct an annual performance test for each nitric acid train according to paragraphs (b)(1...

Process for the extraction of strontium from acidic solutions

DOEpatents

Horwitz, E.P.; Dietz, M.L.

1994-09-06

The invention is a process for selectively extracting strontium values from aqueous nitric acid waste solutions containing these and other fission product values. The extractant solution is a macrocyclic polyether in an aliphatic hydrocarbon diluent containing a phase modifier. The process will selectively extract strontium values from nitric acid solutions which are up to 6 molar in nitric acid. 4 figs.

Process for the extraction of strontium from acidic solutions

DOEpatents

Horwitz, E. Philip; Dietz, Mark L.

1994-01-01

The invention is a process for selectively extracting strontium values from aqueous nitric acid waste solutions containing these and other fission product values. The extractant solution is a macrocyclic polyether in an aliphatic hydrocarbon diluent containing a phase modifier. The process will selectively extract strontium values from nitric acid solutions which are up to 6 molar in nitric acid.

Process for the extraction of strontium from acidic solutions

DOEpatents

Horwitz, E.P.; Dietz, M.L.

1993-01-01

The invention is a process for selectively extracting strontium values from aqueous nitric acid waste solutions containing these and other fission product values. The extractant solution is a macrocyclic polyether in an aliphatic hydrocarbon diluent containing a phase modifier. The process will selectively extract strontium values from nitric acid solutions which are up to 6 molar in nitric acid.

The structure and vibrational frequencies of nitric acid hydrates crystals

NASA Astrophysics Data System (ADS)

Escribano, R.; Fernández, D.; Herrero, V. J.; Maté, B.; Medialdea, A.; Moreno, M. A.; Ortega, I. K.

The relevance of nitric acid hydrates in stratospheric processes has prompted a large number of investigations on the structure and physicochemical properties of these species. We are carrying out in our lab a study on the spectroscopy of crystals of nitric acid and the mono-, di- and trihydrates, NAM, NAD and NAT, respectively, as a first step to addressing more elaborate systems, like binary or ternary mixtures of nitric acid with water, sulphuric acid or halogen compounds of atmospheric interest. Our work consists of a theoretical part, which deals with the determination of the crystalline structure of the species and the prediction of their infrared spectra, and of an experimental part, in which we record Reflection-Absorption infrared spectra of samples prepared under controlled conditions of low pressure and temperature. The theoretical calculations are carried out with the recently developed program SIESTA (acronym for Spanish Initiative for Electronic Simulation of Thousands of Atoms), which allows the ab initio study of periodic systems of large size, by a method that scales linearly in time and computer memory requirements with the number of atoms in a simulation cell. The experimental work is performed on a cryostat cell built in our laboratory. The cell has a number of inlet devices to allow gases to be expanded within, and infrared radiation from a FTIR spectrometer to enter and exit. Films of the species under study are formed by condensing the appropriate gases or mixtures of them on a polished surface of gold or aluminium, whose temperature is controlled externally and can be varied between 80 and 325 K. Examples of experimental and predicted spectra will be presented at the meeting, with a discussion on the proposed assignments.

Image analysis of epicuticular damage to foliage caused by dry deposition of the air pollutant nitric acid.

PubMed

Padgett, Pamela E; Parry, Sally D; Bytnerowicz, Andrzej; Heath, Robert L

2009-01-01

Nitric acid vapor is produced by the same photochemical processes that produce ozone. In the laboratory, concentrated nitric acid is a strong acid and a powerful oxidant. In the environment, where the concentrations are much lower, it is an innocuous source of plant nitrogen. As an air pollutant, which mode of action does dry deposition of nitric acid follow? We investigated the effects of dry deposition of nitric acid on the foliage of four tree species native to the western United States. A novel controlled environment, fumigation system enabled a four-week exposure at concentrations consistent with ambient diurnal patterns. Scanning electron microscopy and automated image analysis revealed changes in the epicuticular wax layer during fumigation. Exposure to nitric acid resulted in a reproducible suite of damage symptoms that increased with increasing dose. Each tree species tested exhibited a unique set of damage features, including cracks, lesions, and conformation changes to epicuticular crystallite structures. Dry deposition of atmospheric nitric acid caused substantial perturbation to the epicuticular surface of all four tree species investigated, consistent with the chemical oxidation of epicuticular waxes. Automated image analysis eliminated many biases that can trouble microscopy studies. Trade names and commercial enterprises or products are mentioned solely for information. No endorsements by the U.S. Department of Agriculture are implied.

The Limb Infrared Monitor of the Stratosphere (LIMS) experiment

NASA Technical Reports Server (NTRS)

Russell, J. M.; Gille, J. C.

1978-01-01

The Limb Infrared Monitor of the Stratosphere is used to obtain vertical profiles and maps of temperature and the concentration of ozone, water vapor, nitrogen dioxide, and nitric acid for the region of the stratosphere bounded by the upper troposphere and the lower mesosphere.

PRESERVATION OF SULFIDIC WATERS CONTAINING DISSOLVED AS (III)

EPA Science Inventory

Field samples for arsenic analyses are commonly preserved by acidification with hydrochloric or nitric acid. In some suboxic samples, appreciable concentrations of H2S and HS- are observed due to the microbial respiration of sulfate-reducing bacteria. If both As(III) and sulfid...

A Simple Approach to Prepare Carboxycellulose Nanofibers from Untreated Biomass.

PubMed

Sharma, Priyanka R; Joshi, Ritika; Sharma, Sunil K; Hsiao, Benjamin S

2017-08-14

A simple approach was developed to prepare carboxycellulose nanofibers directly from untreated biomass using nitric acid or nitric acid-sodium nitrite mixtures. Experiments indicated that this approach greatly reduced the need for multichemicals, and offered significant benefits in lowering the consumption of water and electric energy, when compared with conventional multiple-step processes at bench scale (e.g., TEMPO oxidation). Additionally, the effluent produced by this approach could be efficaciously neutralized using base to produce nitrogen-rich salts as fertilizers. TEM measurements of resulting nanofibers from different biomasses, possessed dimensions in the range of 190-370 and 4-5 nm, having PDI = 0.29-0.38. These nanofibers exhibited lower crystallinity than untreated jute fibers as determined by TEM diffraction, WAXD and 13 C CPMAS NMR (e.g., WAXD crystallinity index was ∼35% for nanofibers vs 62% for jute). Nanofibers with low crystallinity were found to be effective for removal of heavy metal ions for drinking water purification.

METHOD FOR SEPARATION OF PLUTONIUM FROM URANIUM AND FISSION PRODUCTS BY SOLVENT EXTRACTION

DOEpatents

Seaborg, G.T.; Blaedel, W.J.; Walling, M.T. Jr.

1960-08-23

A process is given for separating from each other uranium, plutonium, and fission products in an aqueous nitric acid solution by the so-called Redox process. The plutonium is first oxidized to the hexavalent state, e.g., with a water-soluble dichromate or sodium bismuthate, preferably together with a holding oxidant such as potassium bromate. potassium permanganate, or an excess of the oxidizing agent. The solution is then contacted with a water-immiscible organic solvent, preferably hexone. whereby uranium and plutonium are extracted while the fission products remain in the aqueous solution. The separated organic phase is then contacted with an aqueous solution of a reducing agent, with or without a holding reductant (e.g., with a ferrous salt plus hydrazine or with ferrous sulfamate), whereby plutonium is reduced to the trivalent state and back- extracted into the aqueous solution. The uranium may finally be back-extracted from the organic solvent (e.g., with a 0.1 N nitric acid).

Nitric acid measurements in connection with corrosion studies

NASA Astrophysics Data System (ADS)

Ferm, Martin; De Santis, Franco; Varotsos, Costas

Atmospheric nitric acid does not only contribute to acidification and eutrophication but causes also deterioration of many materials. Material belonging to our cultural heritage is irreplaceable and its lifetime can depend on the corrosion rate. Nowadays, only very few long-term measurements of nitric acid concentration in Europe and elsewhere have been published so far. Due to the fact that atmospheric corrosion is a long-term effect, the relevant research does not necessarily require monitoring of nitric acid on a daily basis. Moreover, power supply is often not available at sites where it is of interest to study the corrosion rate of objects belonging to our cultural heritage. Besides, such measurements must not disturb the impression of the objects. In this context, the diffusive sampling technique provides average concentrations over long-term periods at a low cost. In addition, the samplers used are noiseless, comparatively small in size, and thus, their ambient exposure can be made inconspicuously and with discretion. The present paper is focussed on an intensive corrosion study, which was performed at 11 rural and 23 urban sites in Europe and one rural site in Canada during 2002/2003. For the above-mentioned reasons, the diffusive sampler's technique was employed for the nitric acid monitoring, where the diffusive samplers were first tested against the denuder technique and bi-monthly measurements of nitric acid were thus obtained. The bi-monthly concentrations varied from 0.05 to 4.3 μg m -3 and the annual averages from 0.16 to 2.0 μg m -3. The observations collected, depicted a summertime maximum and a wintertime minimum in the nitric acid concentrations, except at the northern rural sites, where a maximum in the winter was observed. Furthermore, the observed nitric acid concentrations in Southern Europe were higher than in Northern Europe. In a few places, close to the sites of urban measurements, rural measurements of nitric acid were also performed. The obtained nitric acid concentrations were higher in the cities, especially during the period of maximum concentrations.

Gas phase reaction of nitric acid with hydroxyl radical without and with water. A theoretical investigation.

PubMed

Gonzalez, Javier; Anglada, Josep M

2010-09-02

The gas phase reaction between nitric acid and hydroxyl radical, without and with a single water molecule, has been investigated theoretically using the DFT-B3LYP, MP2, QCISD, and CCSD(T) theoretical approaches with the 6-311+G(2df,2p) and aug-cc-pVTZ basis sets. The reaction without water begins with the formation of a prereactive hydrogen-bonded complex and has several elementary reactions processes. They include proton coupled electron transfer, hydrogen atom transfer, and proton transfer mechanisms, and our kinetic study shows a quite good agreement of the behavior of the rate constant with respect to the temperature and to the pressure with the experimental results from the literature. The addition of a single water molecule results in a much more complex potential energy surface although the different elementary reactions found have the same electronic features that the naked reaction. Two transition states are stabilized by the effect of a hydrogen bond interaction originated by the water molecule, and in the prereactive hydrogen bond region there is a geometrical rearrangement necessary to prepare the HO and HNO(3) moieties to react to each other. This step contributes the reaction to be slower than the reaction without water and explains the experimental finding, pointing out that there is no dependence for the HNO(3) + HO reaction on water vapor.

Titanium Dioxide Nanoparticle Integrated Concrete: An Assessment of Nanoparticle Release When Exposed to UV Radiation and Wet Weather Conditions

DTIC Science & Technology

2016-03-23

polystyrene tubes . This procedure was repeated 30 times to simulate an annual exposure to acidic precipitation weathering. The average annual number...with diluted nitric acid in a 10 mL test tube . This sample was used for the ICP-AES analysis. The remainder of the sample solution was acid...Water at a Semiconducter Electrode. Nature 238 9. Gamer AO, Leibold E, van Ravenzwaay B. 2006. The in vitro absorption of microfine zinc oxide and

NASA and ESA Collaboration on Alternative to Nitric Acid Passivation: Parameter Optimization of Citric Acid Passivation for Stainless Steel Alloys

NASA Technical Reports Server (NTRS)

Kessel, Kurt R.

2016-01-01

National Aeronautics and Space Administration (NASA) Headquarters chartered the Technology Evaluation for Environmental Risk Mitigation Principal Center (TEERM) to coordinate agency activities affecting pollution prevention issues identified during system and component acquisition and sustainment processes. The primary objectives of NASA TEERM are to: Reduce or eliminate the use of hazardous materials or hazardous processes at manufacturing, remanufacturing, and sustainment locations. Avoid duplication of effort in actions required to reduce or eliminate hazardous materials through joint center cooperation and technology sharing. Corrosion is an extensive problem that affects the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA). The damaging effects of corrosion result in steep costs, asset downtime affecting mission readiness, and safety risks to personnel. Consequently, it is vital to reduce corrosion costs and risks in a sustainable manner. NASA and ESA have numerous structures and equipment that are fabricated from stainless steel. The standard practice for protection of stainless steel is a process called passivation. Passivation is defined by The American Heritage Dictionary of the English Language as to treat or coat (a metal) in order to reduce the chemical reactivity of its surface. Passivation works by forming a shielding outer (metal oxide) layer that reduces the impact of destructive environmental factors such as air or water. Consequently, this process necessitates a final product that is very clean and free of iron and other contaminants. Typical passivation procedures call for the use of nitric acid; however, there are a number of environmental, worker safety, and operational issues associated with its use. Citric acid is an alternative to nitric acid for the passivation of stainless steels. Citric acid offers a variety of benefits including increased safety for personnel, reduced environmental impact, and reduced operational cost. The primary objective of this effort is to qualify citric acid as an environmentally-preferable alternative to nitric acid for the passivation of stainless steel alloys. While citric acid use has become more prominent in industry, there is little evidence that citric acid is a technically sound passivation agent, especially for the unique and critical applications encountered by NASA and ESA.

Mediated electrochemical oxidation of organic wastes using a Co (III) mediator in a nitric acid based system

DOEpatents

Balazs, G. Bryan; Chiba, Zoher; Lewis, Patricia R.; Nelson, Norvell; Steward, G. Anthony

1999-01-01

An electrochemical cell with a Co(III) mediator and nitric acid electrolyte provides efficient destruction of organic and mixed wastes. The organic waste is concentrated in the anolyte reservoir, where the mediator oxidizes the organics and insoluble transuranic compounds and is regenerated at the anode until the organics are converted to CO.sub.2. The nitric acid is an excellent oxidant that facilitates the destruction of the organic components. The anode is not readily attacked by the nitric acid solution, thus the cell can be used for extended continual operation without electrode replacement.

Nitric Acid Particles in Cold Thick Ice Clouds Observed at Global Scale: Link with Lightning, Temperature, and Upper Tropospheric Water Vapor

NASA Technical Reports Server (NTRS)

Chepfer, H.; Minnis, P.; Dubuisson, P.; Chiriaco, M.; Sun-Mack, S.; Riviere, E. D.

2007-01-01

Signatures of nitric acid particles (NAP) in cold thick ice clouds have been derived from satellite observations. Most NAP are detected in the Tropics (9 to 20% of clouds with T less than 202.5 K). Higher occurrences were found in the rare mid-latitudes very cold clouds. NAP occurrence increases as cloud temperature decreases and NAP are more numerous in January than July. Comparisons of NAP and lightning distributions show that lightning is the main source of the NOx, which forms NAP in cold clouds. Qualitative comparisons of NAP with upper tropospheric humidity distributions suggest that NAP play a role in the dehydration of the upper troposphere when the tropopause is colder than 195K.

Nitric acid particles in cold thick ice clouds observed at global scale: Link with lightning, temperature, and upper tropospheric water vapor

NASA Astrophysics Data System (ADS)

Chepfer, H.; Minnis, P.; Dubuisson, P.; Chiriaco, M.; Sun-Mack, S.; RivièRe, E. D.

2007-03-01

Signatures of nitric acid particles (NAP) in cold thick ice clouds have been derived from satellite observations. Most NAP are detected in the tropics (9 to 20% of clouds with T < 202.5 K). Higher occurrences were found in the rare midlatitudes very cold clouds. NAP occurrence increases as cloud temperature decreases, and NAP are more numerous in January than July. Comparisons of NAP and lightning distributions show that lightning seems to be the main source of the NOx, which forms NAP in cold clouds over continents. Qualitative comparisons of NAP with upper tropospheric humidity distributions suggest that NAP may play a role in the dehydration of the upper troposphere when the tropopause is colder than 195 K.

DISTRIBUTION OF URANIUM, ZIRCONIUM, NIOBIUM, RUTHENIUM AND CERIUM BETWEEN NITRIC ACID SOLUTIONS AND 10% TLA-5% OCTYL ALCOHOL/SHELL SOL-T

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lopez-Menchero, E.; Centeno, J.; Magni, G.

1962-03-01

The extraction of traces of Ru, Zr, Nb, Ce, and U at low concentrations (5 mg/l in aqueous solution) from nitric acid solutions using trilauryl amine (TLA) has been experimentally studied. TLA will eventually be used for final purification of plutonium. Room-temperature data on plutonium contaminant distribution between aqueous solutions of varying nitric acid concentrations and a Shellsol-T solution containing l0% TlA and 5% octyl alcohol are presented. Within the temperature and nitric acid concentration ranges tested, the extractability of uranium increased with increased acid concentrations, although acid concentration in the aqueous phase had no effect on the decontamination factorsmore » for the main fission products. (H.G.G.)« less

Mediated electrochemical oxidation of organic wastes using a Co (III) mediator in a nitric acid based system

DOEpatents

Balazs, G.B.; Chiba, Z.; Lewis, P.R.; Nelson, N.; Steward, G.A.

1999-06-15

An electrochemical cell with a Co(III) mediator and nitric acid electrolyte provides efficient destruction of organic and mixed wastes. The organic waste is concentrated in the anolyte reservoir, where the mediator oxidizes the organics and insoluble transuranic compounds and is regenerated at the anode until the organics are converted to CO[sub 2]. The nitric acid is an excellent oxidant that facilitates the destruction of the organic components. The anode is not readily attacked by the nitric acid solution, thus the cell can be used for extended continual operation without electrode replacement. 2 figs.

SEPARATION OF PLUTONIUM FROM URANIUM AND FISSION PRODUCTS

DOEpatents

Boyd, G.E.; Adamson, A.W.; Schubert, J.; Russell, E.R.

1958-10-01

A chromatographic adsorption process is presented for the separation of plutonium from other fission products formed by the irradiation of uranium. The plutonium and the lighter element fission products are adsorbed on a sulfonated phenol-formaldehyde resin bed from a nitric acid solution containing the dissolved uranium. Successive washes of sulfuric, phosphoric, and nitric acids remove the bulk of the fission products, then an eluate of dilute phosphoric and nitric acids removes the remaining plutonium and fission products. The plutonium is selectively removed by passing this solution through zirconium phosphate, from which the plutonium is dissolved with nitric acid. This process provides a convenient and efficient means for isolating plutonium.

Contribution to the Chemistry of Plasma-Activated Water

NASA Astrophysics Data System (ADS)

Julák, J.; Hujacová, A.; Scholtz, V.; Khun, J.; Holada, K.

2018-01-01

Plasma-activated water (PAW) was prepared by exposure to nonthermal plasma produced by a positive dc corona discharge in a transient spark regime. The activation of water was performed in atmosphere of various surrounding gases (air, nitrogen, carbon dioxide, and argon). This PAW retains its biological activity, measured on the mouse neuroblastoma cells culture, even after storage for more than one year. The highest hydrogen peroxide content was found for PAWs prepared in the atmospheres of argon or carbon dioxide, whereas the PAWs prepared in air and nitrogen exhibited lower hydrogen peroxide content. The acidity of PAWs mediated by nitric and nitrous acid formation displayed an opposite trend. It is concluded that the long-lasting biological effect of PAW is mediated by hydrogen peroxide in acid milieu only, whereas other possible active components decompose rapidly.

Mesoporous Carbons With Self-Assembled High-Activity Surfaces (PREPRINT)

DTIC Science & Technology

2006-07-07

temperature-programmed desorption, and potentiometric titrations . Journal of Colloid and Interface Science 2001; 240: 252–258. [40] Rotkin SV, Gogotsi Y...selected carbon samples were treated with nitric acid and the total acid site density determined by base titration [32-34 Boehm 1994; Boehm 2002; 32...washed thoroughly using distilled/deionized water, and dried in the oven. For the titration , 50 mg of HNO3-treated carbon powder was added to 20 ml

Synthesis and characterization of titanium dioxide (TiO2) nanopowder

NASA Astrophysics Data System (ADS)

Munirah, S.; Nadzirah, Sh.; Khusaimi, Z.; Fazlena, H.; Rusop, M.

2018-05-01

Titanium dioxide (TiO2) powder was synthesized via sol-gel technique using Titanium tetraisopropoxide (TTIP) and ethanol as precursors. Acetylacetone, distilled water, polyethylene glycol (PEG) and stabilizers (glacial acetic acid and nitric acid) were then added to the solution. The solution was left for ageing for 24 hours and then dried into powder. The synthesized powders were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TGA).

Laboratory studies of 2H evaporator scale dissolution in dilute nitric acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oji, L.

The rate of 2H evaporator scale solids dissolution in dilute nitric acid has been experimentally evaluated under laboratory conditions in the SRNL shielded cells. The 2H scale sample used for the dissolution study came from the bottom of the evaporator cone section and the wall section of the evaporator cone. The accumulation rate of aluminum and silicon, assumed to be the two principal elemental constituents of the 2H evaporator scale aluminosilicate mineral, were monitored in solution. Aluminum and silicon concentration changes, with heating time at a constant oven temperature of 90 deg C, were used to ascertain the extent ofmore » dissolution of the 2H evaporator scale mineral. The 2H evaporator scale solids, assumed to be composed of mostly aluminosilicate mineral, readily dissolves in 1.5 and 1.25 M dilute nitric acid solutions yielding principal elemental components of aluminum and silicon in solution. The 2H scale dissolution rate constant, based on aluminum accumulation in 1.5 and 1.25 M dilute nitric acid solution are, respectively, 9.21E-04 ± 6.39E-04 min{sup -1} and 1.07E-03 ± 7.51E-05 min{sup -1}. Silicon accumulation rate in solution does track the aluminum accumulation profile during the first few minutes of scale dissolution. It however diverges towards the end of the scale dissolution. This divergence therefore means the aluminum-to-silicon ratio in the first phase of the scale dissolution (non-steady state conditions) is different from the ratio towards the end of the scale dissolution. Possible causes of this change in silicon accumulation in solution as the scale dissolution progresses may include silicon precipitation from solution or the 2H evaporator scale is a heterogeneous mixture of aluminosilicate minerals with several impurities. The average half-life for the decomposition of the 2H evaporator scale mineral in 1.5 M nitric acid is 12.5 hours, while the half-life for the decomposition of the 2H evaporator scale in 1.25 M nitric acid is 10.8 hours. Based on averaging the two half-lives from the 2H scale acid dissolution in 1.25 and 1.5 M nitric acid solutions, a reasonable half-live for the dissolution of 2H scales in dilute nitric acid is 11.7 ± 1.3 hours. The plant operational time for chemically cleaning (soaking) the 2H evaporator with dilute nitric acid is 32 hours. It therefore may require about 3 half-lives or less to completely dissolve most of the scales in the Evaporator pot which come into contact with the dilute nitric acid solution. On a mass basis, the Al-to-Si ratio for the scale dissolution in 1.5 M nitric acid averaged 1.30 ± 0.20 and averaged 1.18 ± 0.10 for the 2H scale dissolution in 1.25 M nitric acid. These aluminum-to-silicon ratios are in fairly good agreement with ratios from previous studies. Therefore, there is still more aluminum in the 2H evaporator scales than silicon which implies that there are no significant changes in scale properties which will exclude nitric acid as a viable protic solvent for aluminosilicate scale buildup dissolution from the 2H evaporator. Overall, the monitoring of the scale decomposition reaction in 1.25 and 1.5 M nitric acid may be better ascertained through the determination of aluminum concentration in solution than monitoring silicon in solution. Silicon solution chemistry may lead to partial precipitating of silicon with time as the scale and acid solution is heated.« less

Extraction equilibrium of indium(III) from nitric acid solutions by di(2-ethylhexyl)phosphoric acid dissolved in kerosene.

PubMed

Tsai, Hung-Sheng; Tsai, Teh-Hua

2012-01-04

The extraction equilibrium of indium(III) from a nitric acid solution using di(2-ethylhexyl) phosphoric acid (D2EHPA) as an acidic extractant of organophosphorus compounds dissolved in kerosene was studied. By graphical and numerical analysis, the compositions of indium-D2EHPA complexes in organic phase and stoichiometry of the extraction reaction were examined. Nitric acid solutions with various indium concentrations at 25 °C were used to obtain the equilibrium constant of InR₃ in the organic phase. The experimental results showed that the extraction distribution ratios of indium(III) between the organic phase and the aqueous solution increased when either the pH value of the aqueous solution and/or the concentration of the organic phase extractant increased. Finally, the recovery efficiency of indium(III) in nitric acid was measured.

The ν_3 and ν_4 Bands of Nitric Acid (HNO_3) at 7.6 μm for Atmospheric Studies

NASA Astrophysics Data System (ADS)

Perrin, A.; Flaud, J. M.; Ridolfi, M.; Carlotti, M.

2012-06-01

Nitric acid (HNO_3) plays an important role as a reservoir molecule of the NO_x (nitrogen oxides) species in the stratosphere. The three strongest infrared bands of nitric acid are located at 11 μm (ν_5 and 2ν_9 bands), 7.6 μm (the ν_3 and ν_4 bands at 1326 and 1303 cm-1) and 5.8 μm (ν_2 band). Although two times weaker than those located at 7.6 and 5.8 μm, the 11 μm region is the only one which is used for nitric acid retrievals in the atmosphere by several satellite instruments like MIPAS (Michelson Interferometer for Passive Atmospheric Sounding on ENVISAT) or ACE-FTS (ACE Fourier transform spectrometer on SCISAT). This is because the available spectroscopic parameters for HNO_3 in the HITRAN and GEISA databases are of very good quality in this spectral region. Of the two remaining bands, the 7.6 μm one is only partly masked by water, and therefore can be used also for nitric acid retrievals in the upper stratosphere. Moreover, because of their large difference in band intensity, combining measurements at 11 μm and 7.6 μm could maximize informations on the vertical distribution of HNO_3 in the atmosphere. However at 7.6 μm the spectroscopic parameters available in the HITRAN and GEISA databases are are not so good. Indeed, these parameters originate from a list generated more than 20 years ago. The low quality of the list at 7.6 μm prevents HNO_3 retrievals and severely affects the retrievals of several species absorbing in the 7.5-7.7 μm region, like SO_2. This work is a new and more accurate investigation of the line positions and intensities for the ν_3 and ν_4 bands of nitric acid located at 1326.187 and 1303.074 cm-1). For this task, we used new infrared laboratory data combined with a new theoretical model. Examples showing substantial improvements will be given. [1] Rothman et al. J. Quant. Spectrosc. Radiat. Transf., 110, 533-572, 2009 [2] Jacquinet et al. J. Quant. Spectrosc. Radiat. Transf., 112, 2395-2445, 2011 [3] A. Perrin, O. Lado-Bordowski, and A.Valentin, Mol. Physics. 67, 249 (1989) [4] Financial support from the GDRI HiResMIR is gratefully acknowledged

SEPARATION OF PLUTONIUM FROM URANIUM AND FISSION PRODUCTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boyd, G.E.; Adamson, A.W.; Schubert, J.

A chromatographic adsorption process is presented for the separation of plutonium from other fission products formed by the irradiation of uranium. The plutonium and the lighter element fission products are adsorbed on a sulfonated phenol-formaldehyde resin bed from a nitric acid solution containing the dissolved uranium. Successive washes of sulfuric, phosphoric, and nitric acids remove the bulk of the fission products, then an eluate of dilute phosphoric and nitric acids removes the remaining plutonium and fission products. The plutonium is selectively removed by passing this solution through zirconium phosphate, from which the plutonium is dissolved with nitric acid. This processmore » provides a convenient and efficient means for isolating plutonium.« less

Recovery of mercury from acid waste residues

DOEpatents

Greenhalgh, Wilbur O.

1989-01-01

Mercury can be recovered from nitric acid-containing fluids by reacting the fluid with aluminum metal to produce mercury metal, and then quenching the reactivity of the nitric acid prior to nitration of the mercury metal.

Recovery of mercury from acid waste residues

DOEpatents

Greenhalgh, Wilbur O.

1989-12-05

Mercury can be recovered from nitric acid-containing fluids by reacting the fluid with aluminum metal to produce mercury metal, and then quenching the reactivity of the nitric acid prior to nitration of the mercury metal.

Nitrosation and nitration of fulvic acid, peat and coal with nitric acid

USGS Publications Warehouse

Thorn, Kevin A.; Cox, Larry G.

2016-01-01

Nitrohumic acids, produced from base extraction of coals and peats oxidized with nitric acid, have received considerable attention as soil ammendments in agriculture. The nitration chemistry however is incompletely understood. Moreover, there is a need to understand the reaction of nitric acid with natural organic matter (NOM) in general, in the context of a variety of environmental and biogeochemical processes. Suwannee River NOM, Suwannee River fulvic acid, and Pahokee Peat fulvic acid were treated with 15N-labeled nitric acid at concentrations ranging from 15% to 22% and analyzed by liquid and solid state 15N NMR spectroscopy. Bulk Pahokee peat and Illinois #6 coal were also treated with nitric acid, at 29% and 40% respectively, and analyzed by solid state 15N NMR spectroscopy. In addition to nitro groups from nitration of aromatic carbon, the 15N NMR spectra of all five samples exhibited peaks attributable to nitrosation reactions. These include nitrosophenol peaks in the peat fulvic acid and Suwannee River samples, from nitrosation of phenolic rings, and N-nitroso groups in the peat samples, from nitrosation of secondary amides or amines, the latter consistent with the peat samples having the highest naturally abundant nitrogen contents. Peaks attributable to Beckmann and secondary reactions of the initially formed oximes were present in all spectra, including primary amide, secondary amide, lactam, and nitrile nitrogens. The degree of secondary reaction product formation resulting from nitrosation reactions appeared to correlate inversely with the 13C aromaticities of the samples. The nitrosation reactions are most plausibly effected by nitrous acid formed from the reduction of nitric acid by oxidizable substrates in the NOM and coal samples.

Nitrosation and Nitration of Fulvic Acid, Peat and Coal with Nitric Acid

PubMed Central

Thorn, Kevin A.; Cox, Larry G.

2016-01-01

Nitrohumic acids, produced from base extraction of coals and peats oxidized with nitric acid, have received considerable attention as soil ammendments in agriculture. The nitration chemistry however is incompletely understood. Moreover, there is a need to understand the reaction of nitric acid with natural organic matter (NOM) in general, in the context of a variety of environmental and biogeochemical processes. Suwannee River NOM, Suwannee River fulvic acid, and Pahokee Peat fulvic acid were treated with 15N-labeled nitric acid at concentrations ranging from 15% to 22% and analyzed by liquid and solid state 15N NMR spectroscopy. Bulk Pahokee peat and Illinois #6 coal were also treated with nitric acid, at 29% and 40% respectively, and analyzed by solid state 15N NMR spectroscopy. In addition to nitro groups from nitration of aromatic carbon, the 15N NMR spectra of all five samples exhibited peaks attributable to nitrosation reactions. These include nitrosophenol peaks in the peat fulvic acid and Suwannee River samples, from nitrosation of phenolic rings, and N-nitroso groups in the peat samples, from nitrosation of secondary amides or amines, the latter consistent with the peat samples having the highest naturally abundant nitrogen contents. Peaks attributable to Beckmann and secondary reactions of the initially formed oximes were present in all spectra, including primary amide, secondary amide, lactam, and nitrile nitrogens. The degree of secondary reaction product formation resulting from nitrosation reactions appeared to correlate inversely with the 13C aromaticities of the samples. The nitrosation reactions are most plausibly effected by nitrous acid formed from the reduction of nitric acid by oxidizable substrates in the NOM and coal samples. PMID:27175784

Formation of nitric acid hydrates - A chemical equilibrium approach

NASA Technical Reports Server (NTRS)

Smith, Roland H.

1990-01-01

Published data are used to calculate equilibrium constants for reactions of the formation of nitric acid hydrates over the temperature range 190 to 205 K. Standard enthalpies of formation and standard entropies are calculated for the tri- and mono-hydrates. These are shown to be in reasonable agreement with earlier calorimetric measurements. The formation of nitric acid trihydrate in the polar stratosphere is discussed in terms of these equilibrium constants.

10. VIEW OF CALCINER IN ROOM 146148. THE CALCINER HEATED ...

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

10. VIEW OF CALCINER IN ROOM 146-148. THE CALCINER HEATED PLUTONIUM PEROXIDE TO CONVERT IT TO PLUTONIUM OXIDE. THE PROCESS REMOVED RESIDUAL WATER AND NITRIC ACID LEAVING A DRY, POWDERED PRODUCT. (4/29/65) - Rocky Flats Plant, Plutonium Recovery & Fabrication Facility, North-central section of plant, Golden, Jefferson County, CO

Extraction of rare earth oxides using supercritical carbon dioxide modified with Tri- n-butyl phosphate–nitric acid adducts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baek, Donna L.; Fox, Robert V.; Case, Mary E.

A new tri- n-butylphosphate–nitric acid (TBP–HNO 3) adduct was prepared by combining TBP and fuming (90%) HNO 3. The adduct was characterized, and its phase-equilibrium behavior in supercritical carbon dioxide is reported. Supercritical carbon dioxide (sc-CO 2) was modified with this new adduct [TBP(HNO 3) 5.2(H 2O) 1.7], and the extraction efficacies of selected rare earth oxides (Y, Ce, Eu, Tb, and Dy) at 338 K and 34.5 MPa were compared with those obtained using an adduct formed from concentrated (70%) HNO 3 and TBP [TBP(HNO 3) 1.7(H 2O) 0.6]. All rare earth oxides tested with both adduct species couldmore » be extracted with the exception of cerium oxide. Furthermore, the water and acid concentrations in the different adducts were found to play a significant role in rare earth oxide extraction efficiency.« less

Extraction of rare earth oxides using supercritical carbon dioxide modified with Tri- n-butyl phosphate–nitric acid adducts

DOE PAGES

Baek, Donna L.; Fox, Robert V.; Case, Mary E.; ...

2016-06-14

A new tri- n-butylphosphate–nitric acid (TBP–HNO 3) adduct was prepared by combining TBP and fuming (90%) HNO 3. The adduct was characterized, and its phase-equilibrium behavior in supercritical carbon dioxide is reported. Supercritical carbon dioxide (sc-CO 2) was modified with this new adduct [TBP(HNO 3) 5.2(H 2O) 1.7], and the extraction efficacies of selected rare earth oxides (Y, Ce, Eu, Tb, and Dy) at 338 K and 34.5 MPa were compared with those obtained using an adduct formed from concentrated (70%) HNO 3 and TBP [TBP(HNO 3) 1.7(H 2O) 0.6]. All rare earth oxides tested with both adduct species couldmore » be extracted with the exception of cerium oxide. Furthermore, the water and acid concentrations in the different adducts were found to play a significant role in rare earth oxide extraction efficiency.« less

Day-night variability of water-soluble ions in PM10 samples collected at a traffic site in southeastern Spain.

PubMed

Galindo, Nuria; Yubero, Eduardo

2017-01-01

The present work reports diurnal and nocturnal concentrations of water-soluble ions associated to PM 10 samples collected during the warm and cold seasons in the urban center of Elche (Southeastern Spain). Statistical differences between daytime and nighttime levels of PM 10 were only observed during winter. The lower concentrations during the night were most likely the result of a reduction in traffic-induced road dust resuspension, since nocturnal concentrations of calcium also exhibited a significant decrease compared to daytime levels. During the warm season, nitrate was the only component that showed a statistically significant increase from day to night. The lower nocturnal temperatures that prevent the thermal decomposition of ammonium nitrate and the formation of nitric acid favored by the higher relative humidity at night are the most probable reasons for this variation. The close relationship between nitrate formation and relative humidity during nighttime was supported by the results of the correlation analysis. The reaction of sulfuric and nitric acids with CaCO 3 occurred to a greater extent during daytime in summer.

One-Electron Standard Reduction Potentials of Nitroaromatic and Cyclic Nitramine Explosives

DTIC Science & Technology

2010-01-01

the preparation of solutions. Glassware and plasticware was rinsed with acetone and distilled water prior to soaking overnight in a 5.0 M nitric acid ...prior contact with metal ions was soaked in a 5.0 mM oxalic acid bath overnight before following the above procedure. 40-Nitroacetophenone, 1,3...observable (Colon et al., 2006b) nitrosobenzene and N-hydroxylaniline intermediates to form the final stable product aniline (Fig. 1a). However, NACs

Recovery of mercury from acid waste residues

DOEpatents

Greenhalgh, W.O.

1987-02-27

Mercury can be recovered from nitric acid-containing fluids by reacting the fluid with aluminum metal to produce mercury metal, and thence quenching the reactivity of the nitric acid prior to nitration of the mercury metal. 1 fig.

Water Accommodation on Bare and Coated Ice

NASA Astrophysics Data System (ADS)

Kong, Xiangrui

2015-04-01

A good understanding of water accommodation on ice surfaces is essential for quantitatively predicting the evolution of clouds, and therefore influences the effectiveness of climate models. However, the accommodation coefficient is poorly constrained within the literature where reported values vary by up to three orders of magnitude. In addition, the complexity of the chemical composition of the atmosphere plays an important role in ice phase behavior and dynamics. We employ an environmental molecular beam (EMB) technique to investigate molecular water interactions with bare and impurity coated ice at temperatures from 170 K to 200 K. In this work, we summarize results of water accommodation experiments on bare ice (Kong et al., 2014) and on ice coated by methanol (Thomson et al., 2013), butanol (Thomson et al., 2013) and acetic acid (Papagiannakopoulos et al., 2014), and compare those results with analogous experiments using hexanol and nitric acid coatings. Hexanol is chosen as a complementary chain alcohol to methanol and butanol, while nitric acid is a common inorganic compound in the atmosphere. The results show a strong negative temperature dependence of water accommodation on bare ice, which can be quantitatively described by a precursor model. Acidic adlayers tend to enhance water uptake indicating that the system kinetics are thoroughly changed compared to bare ice. Adsorbed alcohols influence the temperature dependence of the accommodation coefficient and water molecules generally spend less time on the surfaces before desorbing, although the measured accommodation coefficients remain high and comparable to bare ice for the investigated systems. We conclude that impurities can either enhance or restrict water uptake in ways that are influenced by several factors including temperature and type of adsorbant, with potential implications for the description of ice particle growth in the atmosphere. This work was supported by the Swedish Research Council and The Nordic Centre of Excellence CRAICC. Reference: X.R. Kong, P. Papagiannakopoulos, E.S. Thomson, J.B.C. Pettersson, Water Accommodation and Desorption Kinetics on Ice, J. Phys. Chem. A, 118 (2014) 3973-3979. E.S. Thomson, X. Kong, N. Markovic, P. Papagiannakopoulos, J.B.C. Pettersson, Collision dynamics and uptake of water on alcohol-covered ice, Atmos. Chem. Phys. 13 (2013) 2223-2233. P. Papagiannakopoulos, X.R. Kong, E.S. Thomson, J.B.C. Pettersson, Water Interactions with Acetic Acid Layers on Ice and Graphite, J. Phys. Chem. B, (2014) doi: 10.1021/jp503552w.

Upper-atmosphere Aerosols: Properties and Natural Cycles

NASA Technical Reports Server (NTRS)

Turco, Richard P.

1992-01-01

The middle atmosphere is rich in its variety of particulate matter, which ranges from meteorite debris, to sulfate aerosols, to polar stratospheric ice clouds. Volcanic eruptions strongly perturb the stratospheric sulfate (Junge) layer. High-altitude 'noctilucent' ice clouds condense at the summer mesopause. The properties of these particles, including their composition, sizes, and geographical distribution, are discussed, and their global effects, including chemical, radiative, and climatic roles, are reviewed. Polar stratospheric clouds (PSCs) are composed of water and nitric acid in the form of micron-sized ice crystals. These particles catalyze reactions of chlorine compounds that 'activate' otherwise inert chlorine reservoirs, leading to severe ozone depletions in the southern polar stratosphere during austral spring. PSCs also modify the composition of the polar stratosphere through complex physiocochemical processes, including dehydration and denitrification, and the conversion of reactive nitrogen oxides into nitric acid. If water vapor and nitric acid concentrations are enhanced by high-altitude aircraft activity, the frequency, geographical range, and duration of PSCs might increase accordingly, thus enhancing the destruction of the ozone layer (which would be naturally limited in geographical extent by the same factors that confine the ozone hole to high latitudes in winter). The stratospheric sulfate aerosol layer reflects solar radiation and increases the planetary albedo, thereby cooling the surface and possibly altering the climate. Major volcanic eruptions, which increase the sulfate aerosol burden by a factor of 100 or more, may cause significant global climate anomalies. Sulfate aerosols might also be capable of activating stratospheric chlorine reservoirs on a global scale (unlike PCSs, which represent a localized polar winter phenomenon), although existing evidence suggests relatively minor perturbations in chlorine chemistry. Nevertheless, if atmospheric concentrations of chlorine (associated with anthropogenic use of chlorofluorocarbons) continue to increase by a factor of two or more in future decades, aircraft emissions of sulfur dioxide and water vapor may take on greater significance.

Flower-like Rh/Cu superhydrophobic coating via electrodeposition and its self-cleaning property

NASA Astrophysics Data System (ADS)

Zhao, N.; Lu, S. X.; Xu, W. G.; Cheng, X. L.

2017-01-01

Rh/Cu superhydrophobic coatings with textured flower-like dual micro-nano structures were fabricated on copper substrates via electrodesposition of Rh followed by annealing treatment. The scanning electron microscopy and X-ray diffraction pattern were conducted to analyse the morphology and chemical composition of the coating surfaces, respectively. The water drops exhibited a water contact angle of 168±1° and a sliding angle of 0±1° on the coating surfaces which were obtained by etching in concentrated hydrochloric acid and nitric acid, electrodeposited at -1.0 V for 30 min and annealing in an oven at 180°C for 60 min. The prepared superhydrophobic coatings showed excellent water repellence and self-cleaning property due to its extremely high water contact angle.

Uranium carbide dissolution in nitric solution: Sonication vs. silent conditions

NASA Astrophysics Data System (ADS)

Virot, Matthieu; Szenknect, Stéphanie; Chave, Tony; Dacheux, Nicolas; Moisy, Philippe; Nikitenko, Sergey I.

2013-10-01

The dissolution of uranium carbide (UC) in nitric acid media is considered by means of power ultrasound (sonication) or magnetic stirring. The induction period required to initiate UC dissolution was found to be dramatically shortened when sonicating a 3 M nitric solution (Ar, 20 kHz, 18 W cm-2, 20 °C). At higher acidity, magnetic stirring offers faster dissolution kinetics compared to sonication. Ultrasound-assisted UC dissolution is found to be passivated after ∼60% dissolution and remains incomplete whatever the acidity which is confirmed by ICP-AES, LECO and SEM-EDX analyses. In general, the kinetics of UC dissolution is linked to the in situ generation of nitrous acid in agreement with the general mechanism of UC dissolution; the nitrous acid formation is reported to be faster under ultrasound at low acidity due to the nitric acid sonolysis. The carbon balance shared between the gaseous, liquid, and solid phases is strongly influenced by the applied dissolution procedure and HNO3 concentration.

The Importance of Ammonia for Winter Haze Formation in Two Oil and Gas Production Regions

NASA Astrophysics Data System (ADS)

Collett, J. L., Jr.; Li, Y.; Evanoski-Cole, A. R.; Sullivan, A.; Day, D.; Archuleta, C.; Tigges, M.; Sewell, H. J.; Prenni, A. J.; Schichtel, B. A.

2014-12-01

Fine particle ammonium nitrate formation results from the atmospheric reaction of gaseous ammonia and nitric acid. This reaction is most important in winter when low temperatures thermodynamically enhance particle formation. Nitrogen oxides emissions from oil and gas operations partially react in the atmosphere to form nitric acid. The availability of atmospheric ammonia plays an important role in determining whether the nitric acid formed results in wintertime ammonium nitrate formation. Here we contrast situations in two important U.S. oil and gas production regions. Measurements of ammonia, nitric acid, ammonium nitrate and other species were made from 2007 to present near Boulder, Wyoming and in winters 2013 and 2014 in western North Dakota. The Boulder, Wyoming site is close to the large Jonah and Pinedale Anticline gas fields. Field sites at the north unit of Theodore Roosevelt National Park and Fort Union are situated in the large Bakken Formation oil and gas production region. Wintertime formation of nitric acid and ammonium nitrate, together comprising nitrogen in the +5 oxidation state (N(V)), was observed in both locations. Concentrations of N(V), however, are generally much lower at Boulder, WY than in the Bakken. An even bigger difference is seen in fine particle ammonium nitrate concentrations; limited regional ammonia is available in western Wyoming to react with nitric acid, leaving a portion of the nitric acid trapped in the gas phase. Higher concentrations of ammonia are observed in the Bakken where they support formation of much higher concentrations of ammonium nitrate. Comparison of these two regions clearly indicates the importance of understanding both local NOx emissions and regional concentrations of ammonia in predicting source impacts on formation of fine particles and haze.

Studies on the oxidation of hexamethylbenzene 1: Oxidation of hexamethylbenzene with nitric acid

NASA Technical Reports Server (NTRS)

Chiba, K.; Tomura, S.; Mizuno, T.

1986-01-01

The oxidative reaction of hexamethylbenzene (HMB) with nitric acid was studied, and the hitherto unknown polymethylbenzenepolycarboxylic acids were isolated: tetramethylphthalic anhydride, tetramethylisophthalic acid, 1,3,5-, 1,2,4- and 1,2,3-trimethylbenzenetricarboxylic acids. When HMB was warmed with 50% nitric acid at about 80 C, tetramethylphthalic anhydride and tetramethylisophthalic acid were initially produced. The continued reaction led to the production of trimethylbenzenetricarboxylic acids, but only slight amounts of dimethylbenzenetetracarboxylic acids were detected in the reaction mixture. Whereas tetramethylphthalic anydride and tetramethylisophthalic acid were obtained, pentamethylbenzoic acid, a possible precursor of them, was scarcely produced. On the other hand, a yellow material extracted with ether from the initial reaction mixture contained bis-(nitromethyl)prehnitene (CH3)4C6(CH2NO2)2, which was easily converted into the phthalic anhydride.

The Role of Stress in the Corrosion Cracking of Aluminum Alloys

DTIC Science & Technology

2013-03-01

Corrosion IGSCC Intergranular Stress Corrosion Cracking NAMLT Nitric Acid Mass Loss Test SCC Stress Corrosion Cracking TGSCC Transgranular Stress...solution at a nitric acid mass loss test (NAMLT) value of 49 mg/cm 2 with an applied voltage of 0.73 VSCE. They also showed that the amount of corrosion ...for determining the susceptibility to intergranualr corrosion of 5XXX series aluminum alloys by mass loss after exposure to nitric acid ," vol.

Copper Complex in Poly(vinyl chloride) as a Nitric Oxide-Generating Catalyst for the Control of Nitrifying Bacterial Biofilms.

PubMed

Wonoputri, Vita; Gunawan, Cindy; Liu, Sanly; Barraud, Nicolas; Yee, Lachlan H; Lim, May; Amal, Rose

2015-10-14

In this study, catalytic generation of nitric oxide by a copper(II) complex embedded within a poly(vinyl chloride) matrix in the presence of nitrite (source of nitric oxide) and ascorbic acid (reducing agent) was shown to effectively control the formation and dispersion of nitrifying bacteria biofilms. Amperometric measurements indicated increased and prolonged generation of nitric oxide with the addition of the copper complex when compared to that with nitrite and ascorbic acid alone. The effectiveness of the copper complex-nitrite-ascorbic acid system for biofilm control was quantified using protein analysis, which showed enhanced biofilm suppression when the copper complex was used in comparison to that with nitrite and ascorbic acid treatment alone. Confocal laser scanning microscopy (CLSM) and LIVE/DEAD staining revealed a reduction in cell surface coverage without a loss of viability with the copper complex and up to 5 mM of nitrite and ascorbic acid, suggesting that the nitric oxide generated from the system inhibits proliferation of the cells on surfaces. Induction of nitric oxide production by the copper complex system also triggered the dispersal of pre-established biofilms. However, the addition of a high concentration of nitrite and ascorbic acid to a pre-established biofilm induced bacterial membrane damage and strongly decreased the metabolic activity of planktonic and biofilm cells, as revealed by CLSM with LIVE/DEAD staining and intracellular adenosine triphosphate measurements, respectively. This study highlights the utility of the catalytic generation of nitric oxide for the long-term suppression and removal of nitrifying bacterial biofilms.

Electronic Transport Properties of Carbon-Nanotube Networks: The Effect of Nitrate Doping on Intratube and Intertube Conductances

NASA Astrophysics Data System (ADS)

Ketolainen, T.; Havu, V.; Jónsson, E. Ö.; Puska, M. J.

2018-03-01

The conductivity of carbon-nanotube (CNT) networks can be improved markedly by doping with nitric acid. In the present work, CNTs and junctions of CNTs functionalized with NO3 molecules are investigated to understand the microscopic mechanism of nitric acid doping. According to our density-functional-theory band-structure calculations, there is charge transfer from the CNT to adsorbed molecules indicating p -type doping. The average doping efficiency of the NO3 molecules is higher if the NO3 molecules form complexes with water molecules. In addition to electron transport along individual CNTs, we also study electron transport between different types (metallic, semiconducting) of CNTs. Reflecting the differences in the electronic structures of semiconducting and metallic CNTs, we find that in addition to turning semiconducting CNTs metallic, doping further increases electron transport most efficiently along semiconducting CNTs as well as through the junctions between them.

Inhibition of Titanium In Fuming Nitric Acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

RITTENHOUSE, J. B.; PAPP, C. A.

1958-06-01

Storage tests were conducted to determine the effectiveness of oxygen in inhibiting the corrosion reaction of titanium in fuming nitric acid (FNA). In these tests, which were of 28 days duration at a temperature of 30 C, the samples investigated were ½-inch squares (0.020 inch thick) of commercially pure titanium (75A) and a binary 8 percent-manganese alloy (C110M). The specimens were stored in Teflon-lined aluminum pressure vessels at 50 percent ullage. The pressure vessels were of the following types: vented to the atmosphere, sealed with air in the vapor space, sealed with oxygen atmosphere in the vapor space, and equippedmore » for a 1-ml/minute oxygen flow through the vapor space. Finally, results of the investigation indicated no inhibition of titanium corrosion by oxygen, but confirmed the inhibiting effect of a water content of 1 to 2 percent by weight in the FNA.« less

Evidence That Nitric Acid Increases Relative Humidity in Low-Temperature Cirrus Clouds

NASA Technical Reports Server (NTRS)

Gao, R. S.; Popp, P. J.; Fahey, D. W.; Marcy, T. P.; Herman, R. L.; Weinstock, E. M.; Baumgardner, D. G.; Garrett, T. J.; Rosenlof, K. H.; Thompson, T. L.

2004-01-01

In situ measurements of the relative humidity with respect to ice (RH(sub(i)) and of nitric acid (HNO3) were made in both natural and contrail cirrus clouds in the upper troposphere. At temperatures lower than 202 kelvin, RH(sub i) values show a sharp increase to average values of over 130% in both cloud types. These enhanced RH(sub i) values are attributed to the presence of a new class of NHO3- containing ice particles (Delta-ice). We propose that surface HNO3 molecules prevent the ice/vapor system from reaching equilibrium by a mechanism similar to that of freezing point depression by antifreeze proteins. Delta-ice represents a new link between global climate and natural and anthropogenic nitrogen oxide emissions. Including Delta-ice in climate models will alter simulated cirrus properties and the distribution of upper tropospheric water vapor.

Preparation of ethylenediamine dinitrate

DOEpatents

Lee, Kien-yin

1985-01-01

Method for the preparation of ethylenediamine dinitrate. Ethylenediamine dinitrate, a useful explosive, may readily be prepared by solvent extraction of nitrate ion from an acidic aqueous solution thereof using a high-molecular-weight, water-insoluble amine dissolved in an organic solvent, and reacting the resulting organic solution with ethylenediamine. The process of the instant invention avoids the use of concentrated nitric acid, as is currently practiced, resulting in a synthesis which is far less hazardous especially for large quantities of the explosive, and more efficient.

Dissolution process for ZrO.sub.2 -UO.sub.2 -CaO fuels

DOEpatents

Paige, Bernice E.

1976-06-22

The present invention provides an improved dissolution process for ZrO.sub.2 -UO.sub.2 -CaO-type pressurized water reactor fuels. The zirconium cladding is dissolved with hydrofluoric acid, immersing the ZrO.sub.2 -UO.sub.2 -CaO fuel wafers in the resulting zirconium-dissolver-product in the dissolver vessel, and nitric acid is added to the dissolver vessel to facilitate dissolution of the uranium from the ZrO.sub.2 -UO.sub.2 -CaO fuel wafers.

Preparation of ethylenediamine dinitrate

DOEpatents

Lee, K.

1984-05-17

Method for the preparation of ethylenediamine dinitrate. Ethylenediamine dinitrate, a useful explosive, may readily be prepared by solvent extraction of nitrate ion from an acidic aqueous solution thereof using a high-molecular-weight, water-insoluble amine dissolved in an organic solvent, and reacting the resulting oraganic solution with ethylenediamine. The process of the instant invention avoids the use of concentrated nitric acid, as is currently practiced, resulting in a synthesis which is far less hazardous, especially for large quantities of the explosive, and more efficient.

SOLVENT EXTRACTION PROCESS FOR PLUTONIUM

DOEpatents

Seaborg, G.T.

1959-04-14

The separation of plutonium from aqueous inorganic acid solutions by the use of a water immiscible organic extractant liquid is described. The plutonium must be in the oxidized state, and the solvents covered by the patent include nitromethane, nitroethane, nitropropane, and nitrobenzene. The use of a salting out agents such as ammonium nitrate in the case of an aqueous nitric acid solution is advantageous. After contacting the aqueous solution with the organic extractant, the resulting extract and raffinate phases are separated. The plutonium may be recovered by any suitable method.

Corrosion behavior of ODS steels with several chromium contents in hot nitric acid solutions

NASA Astrophysics Data System (ADS)

Tanno, Takashi; Takeuchi, Masayuki; Ohtsuka, Satoshi; Kaito, Takeji

2017-10-01

Oxide dispersion strengthened (ODS) steel cladding tubes have been developed for fast reactors. Tempered martensitic ODS steels with 9 and 11 wt% of chromium (9Cr-, 11Cr-ODS steel) are the candidate material in research being carried out at JAEA. In this work, fundamental immersion tests and electrochemical tests of 9 to 12Cr-ODS steels were systematically conducted in various nitric acid solutions at 95 °C. The corrosion rate decreased exponentially with effective solute chromium concentration (Creff) and nitric acid concentration. Addition of vanadium (V) and ruthenium (Ru) also decreased the corrosion rate. The combination of low Creff and dilute nitric acid could not avoid the active mass dissolution during active domain at the beginning of immersion, and the corrosion rate was high. Higher Creff decreased the partial anodic current during the active domain and assisted the passivation of the surface of the steel. Concentrated nitric acid and addition of Ru and V increased partial cathodic current and shifted the corrosion potential to noble side. These effects should have prevented the active mass dissolution and decreased the corrosion rate.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abraham, W.M.; Kim, C.S.; King, M.M.

The airway effects of a 4-hr exposure (via a Plexiglas hood) to 1.6 ppm nitric acid vapor were evaluated in seven normal and seven allergic sheep, i.e., animals that have a history of reacting with bronchospasm to inhalation challenge with Ascaris suum antigen. The nitric acid vapor was generated by ultrasonic nebulization of a 2% nitric acid solution. Airway effects were assessed by measuring the change in specific pulmonary flow resistance before and after a standard inhalation challenge with 2.5% carbachol aerosol. Nitric acid exposure did not produce bronchoconstriction in either group. Pre-exposure increases in specific pulmonary flow resistance aftermore » carbachol inhalation were 68% (SD+/- 13%) and 82% (SD+/- 35%) for the normal and allergic sheep, respectively. Within 24 hr, the largest post-exposure increases in specific pulmonary flow resistance for the normal and allergic sheep were 108% (SD+/- 51%(P<.06)) and 175% (SD+/- 87% (p<.02)), respectively. We conclude that a short-term exposure to nitric acid vapor at levels below the industrial threshold limit (2 ppm), produces airway hyperreactivity to aerosolized carbachol in allergic sheep.« less

What does nitric acid really do to carbon nanofibers? [What nitric acid really does to carbon nanofibers

DOE PAGES

Sainio, S.; Nordlund, D.; Gandhiraman, R.; ...

2016-09-15

Understanding the chemical nature of the surface of carbon nanofibers (CNF) is critical in assessing their fundamental properties and tailoring them for the right application. To gain such knowledge, we present here a detailed X-ray adsorption spectroscopy (XAS) study accompanied by high resolution transmission electron microscopy (TEM) micrographs of two morphologically different CNF pairs (tetrahedral amorphous carbon (ta-C) grown “open structured” fibers and traditional bamboo-like “closed structured” fibers), where the surface chemical properties and structural features of the fibers are investigated in depth and the effects of nitric acid treatment on the fibers are revealed. The morphology of the fibermore » and/or the original seed- and adhesion layers markedly affect the response of the fibers to the acid treatment. Results also show that the nitric acid treatment increases the observed sp 2 intensity and modifies the two types of fibers to become more-alike both structurally and with respect to their oxygen functionalities. Furthermore, the XAS and HRTEM results confirm that a short nitric acid treatment does not remove the Ni catalyst particle but, instead, oxidizes their surfaces, especially in the case of ta-C grown fibers.« less

What does nitric acid really do to carbon nanofibers? [What nitric acid really does to carbon nanofibers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sainio, S.; Nordlund, D.; Gandhiraman, R.

Understanding the chemical nature of the surface of carbon nanofibers (CNF) is critical in assessing their fundamental properties and tailoring them for the right application. To gain such knowledge, we present here a detailed X-ray adsorption spectroscopy (XAS) study accompanied by high resolution transmission electron microscopy (TEM) micrographs of two morphologically different CNF pairs (tetrahedral amorphous carbon (ta-C) grown “open structured” fibers and traditional bamboo-like “closed structured” fibers), where the surface chemical properties and structural features of the fibers are investigated in depth and the effects of nitric acid treatment on the fibers are revealed. The morphology of the fibermore » and/or the original seed- and adhesion layers markedly affect the response of the fibers to the acid treatment. Results also show that the nitric acid treatment increases the observed sp 2 intensity and modifies the two types of fibers to become more-alike both structurally and with respect to their oxygen functionalities. Furthermore, the XAS and HRTEM results confirm that a short nitric acid treatment does not remove the Ni catalyst particle but, instead, oxidizes their surfaces, especially in the case of ta-C grown fibers.« less

THE SOLVENT EXTRACTION OF NITROSYLRUTHENIUM BY TRILAURYLAMINE IN NITRATE SYSTEM. Summary Report for the Period, July 1, 1960 to March 31, 1962

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skavdahl, R.E.; Mason, E.A.

1962-06-01

An investigation of the solvent extraction characteristics of the nitro and nitrato complexes of nitrosylruthenium in nitric acid- sodium nitrate aqueous media was conducted. As the organic extractant phase, a solution of trilaurylamine (TLA) in toluene was utilized. In addition to the usual process parameter variation tyne of experiment, a rapid dilution type of experiment was used extensively to determine qualitative and semiquantitative results regarding the degree of extractability and concentration of the more extractable species of the nitrato complexes of nitrosylruthenium. It was found that the acids of the tetra-nitrato and pentanitrato complexes were the more extractable species formore » that set of complexes and that the acid of the penta-nitrato complex was the more extractable of the two. It was observed that for freshly prepared solutions, the dinitro complex of nitrosylruthenium was much more extractable than the gross nitrato complexes solutions. Nitro complexes in general, and the dinitro complex in particular, may be the controlling agent in ruthenium decontamination of spent nuclear fuel processed by solvent extraction methods. The experimental results from both sets of complexes could be more meaningfully correlated on the basis of unbound nitric acid concentration in the organic phase than on the basis of nitric acid concentration in the aqueous phase. The extraction of nitric acid by TLA from nitric acid-sodium nitrate aqueous solutions was investigated and the results correlated on the basis of activity of the undissociated nitric acid in the aqueous phase. (auth)« less

Salt and nitric oxide synthase inhibition-induced hypertension: kidney dysfunction and brain anti-oxidant capacity.

PubMed

Oktar, Süleyman; Ilhan, Selçuk; Meydan, Sedat; Aydin, Mehmet; Yönden, Zafer; Gökçe, Ahmet

2010-01-01

The specific aim of this study was to examine the effects of salt-loading on kidney function and brain antioxidant capacity. Wistar rats were divided into four groups: Control rats were given normal drinking water and no drug treatment for 2 weeks. LNNA group: rats were given normal drinking water and the nitric oxide (NO) inhibitor NG-nitro-L-arginine (L-NNA), 3 mg/kg/day. LNNA + Salt group: rats were given drinking water containing salt 2% and 3 mg/kg L-NNA. Salt group: rats were given drinking water containing salt 2% and no drug treatment. Basal blood pressure and the levels of serum BUN, creatinine, uric acid, cortisol, electrolyte, serum antioxidant capacity, and oxidative stress were measured. NO, superoxide dismutase (SOD), and catalase (CAT) levels were measured in the hypothalamus, brainstem, and cerebellum. Salt overload increased the blood pressure of the LNNA + Salt group. Salt-loading enhanced BUN, creatinine, sodium retention. High salt produced an increase in uric acid levels and a decrease in cortisol levels in serum. Additionally, the oxidative stress index in serum increased in the LNNA + Salt group. Salt-loading enhanced brain NO levels, but not SOD and CAT activity. L-NNA increased brain SOD activity, but not CAT and NO levels. In conclusion, salt-loading causes hypertension, kidney dysfunction, and enhances oxidative stress in salt-sensitive rats.

Chemical of the Month: Nitric Acid.

ERIC Educational Resources Information Center

Pannu, Sardul S.

1984-01-01

Presents background information on nitric acid including old names, history, occurrence, methods of preparation, uses, production, and price. Includes such chemical properties as decomposition; acidity, oxidation of metals and nonmetals; reactions with organic and inorganic compounds; gaseous fluorine; and nitrating properties. Also discusses bond…

IDAHO CHEMICAL PROCESSING PLANT TECHNICAL PROGRESS REPORT FOR APRIL THROUGH JUNE 1958

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stevenson, C.E.

1958-11-01

Processing of uranium -aluminum alloy was continued with slight process modifications. Means for recovering rare gases from dissolver off-gas are described. Results of extensive decontamination procedures required to enable entrance to the continuous dissolver cell are also indicated. Pilot plant studies of dissolving aluminum continuously showed that rates of dissolution were decreased by factors of 2 to 4 as the concentration of nitric acid fed was increased from 5.4 to 11N. The rate of aluminum dissolution was found to be proportional to initial area exposed for pieces of different shape. It was found possible to produce a highly basic aluminummore » nitrate solution at a reasonable rate by dissolving to low concentration in dilute acid, followed by evaporation to the desired level. Uranium exchange rate measurements for the TBP extraction process are described. A canned rotor pump under test with graphite bearings operated 6000 hours with nominal wear. Difficulties were experienced in testing a nutating disc pump. Measurements of the potential of zirconium in hydrofluoric acid as a function of pH confirmed the predicted equation. In teflon vessels, zirconium dissolves a little more rapidly in nitric-hydrofluoric acid mixtures than in glass vessels, presumably due to reaction of fluoride with silica. Titunium alloy Types 55A and 75A were found to resist corrosion by certain boiling nitric-hydrochloric acid mixtures. Initial tests have commenced with a NaK-heated 100 liter/hour pilot plant aluminum nitrate calciner to continue process demonstration. In tests in the smaller pilot plant unit, increasing feed spray air ratio was found to increase particle loading in the cyclone effluent. Laboratory studies indicated that a venturi scrubber using dilute nitric acid at 80 C should remove ruthenium effectively from calciner off-gas. In a pilot plant test in which a significant fraction of ruthenium feed was retained by the alumina, substantial absorption of volatilized ruthenium was obtained. Thermal conductivity of alumina near 3000 F was about 0.26 Btu/hr)(ft)( F). In leaching studies, very little strontium or plutonium was removed by water from alumina calcined at 550 C. Dilute nitric acid, however, extracted strontium from this material to the same degree (~ 50 percent) as from material calcined at 400 C. Concentrated basic aluminum nitrate was produced from simulated aluminum nitrate waste by slow hydrolysis with urea followed by evaporation. Aluminum was efficiently extracted from buffered aluminum nitrate solution by acetylacetone and was stripped back into nitric acid. A filterable aluminum phosphate was precipituted from aluminum nitrate solution by urea hydrolysis; the phosphate effectively carried fission products, however. Spectrophotometric methods were developed for macro and micro quantities of uranium, in the presence of high concentrations of other ions, based on tetrapropylammonium nitrate extraction. (For preceding period see ID0-14443.) (auth)« less

Nitric acid poisoning

MedlinePlus

... Board on Environmental Studies and Toxicology; Division on Earth and Life Studies; National Research Council. Nitric acid: ... Board on Environmental Studies and Toxicology; Division on Earth and Life Studies; National Research Council. Acute Exposure ...

Photochemical organonitrate formation in wet aerosols

NASA Astrophysics Data System (ADS)

Lim, Yong Bin; Kim, Hwajin; Kim, Jin Young; Turpin, Barbara J.

2016-10-01

Water is the most abundant component of atmospheric fine aerosol. However, despite rapid progress, multiphase chemistry involving wet aerosols is still poorly understood. In this work, we report results from smog chamber photooxidation of glyoxal- and OH-containing ammonium sulfate or sulfuric acid particles in the presence of NOx and O3 at high and low relative humidity. Particles were analyzed using ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). During the 3 h irradiation, OH oxidation products of glyoxal that are also produced in dilute aqueous solutions (e.g., oxalic acids and tartaric acids) were formed in both ammonium sulfate (AS) aerosols and sulfuric acid (SA) aerosols. However, the major products were organonitrogens (CHNO), organosulfates (CHOS), and organonitrogen sulfates (CHNOS). These were also the dominant products formed in the dark chamber, indicating non-radical formation. In the humid chamber (> 70 % relative humidity, RH), two main products for both AS and SA aerosols were organonitrates, which appeared at m / z- 147 and 226. They were formed in the aqueous phase via non-radical reactions of glyoxal and nitric acid, and their formation was enhanced by photochemistry because of the photochemical formation of nitric acid via reactions of peroxy radicals, NOx and OH during the irradiation.

Sensitization of Naturally Aged Aluminum 5083 Armor Plate

DTIC Science & Technology

2015-07-29

susceptibility to intergranular corrosion of 5XXX series aluminum alloys by mass loss after exposure to nitric acid (NAMLT Test)”, ASTM G-67-04. [6...67 nitric acid mass-loss values were 19 to 25 mg/cm2. The transmission electron microscopy microstructure of the sample was found to be consistent...5XXX Series Aluminum Alloys by Mass Loss after Exposure to Nitric Acid “ was used as an assessment of the degree of sensitization (DOS) of the alloy.[5

TREATMENT OF URANIUM SURFACES

DOEpatents

Slunder, C.J.

1959-02-01

An improved process is presented for prcparation of uranium surfaces prior to electroplating. The surfacc of the uranium to be electroplated is anodized in a bath comprising a solution of approximately 20 to 602 by weight of phosphoric acid which contains about 20 cc per liter of concentrated hydrochloric acid. Anodization is carried out for approximately 20 minutes at a current density of about 0.5 amperes per square inch at a temperature of about 35 to 45 C. The oxidic film produced by anodization is removed by dipping in strong nitric acid, followed by rinsing with water just prior to electroplating.

Supercritical fluid extraction and separation of uranium from other actinides.

PubMed

Quach, Donna L; Mincher, Bruce J; Wai, Chien M

2014-06-15

The feasibility of separating U from nitric acid solutions of mixed actinides using tri-n-butylphosphate (TBP)-modified supercritical fluid carbon dioxide (sc-CO2) was investigated. The actinides U, Np, Pu, and Am were extracted into sc-CO2 modified with TBP from a range of nitric acid concentrations, in the absence of, or in the presence of, a number of traditional reducing and/or complexing agents to demonstrate the separation of these metals from U under sc-CO2 conditions. The separation of U from Pu using sc-CO2 was successful at nitric acid concentrations of less than 3M in the presence of acetohydroxamic acid (AHA) or oxalic acid (OA) to mitigate Pu extraction, and the separation of U from Np was successful at nitric acid concentrations of less than 1M in the presence of AHA, OA, or sodium nitrite to mitigate Np extraction. Americium was not well extracted under any condition studied. Copyright © 2014 Elsevier B.V. All rights reserved.

Oleic acid-dependent modulation of Nitric oxide associated 1 protein levels regulates nitric oxide-mediated defense signaling in Arabidopsis

USDA-ARS?s Scientific Manuscript database

The conserved cellular metabolites nitric oxide (NO) and oleic acid (18:1) are well-known regulators of disease physiologies in diverse organism. We show that NO production in plants is regulated via 18:1. Reduction in 18:1 levels, via a genetic mutation in the 18:1-synthesizing gene SUPPRESSOR OF S...

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

ERIC Educational Resources Information Center

Bretherick, Leslie

1989-01-01

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

NONLINEARITIES IN THE SULFATE SECONDARY FINE PARTICULATE RESPONSE TO NOX EMISSIONS REDUCTIONS AS MODELED BY THE REGIONAL ACID DEPOSITION MODEL

EPA Science Inventory

Attention is increasingly being devoted to the health effects of fine particulates. In regions that have a large production of sulfate, sulfuric acid and nitric acid compete for the available ammonia to form aerosols. In addition, the available nitric acid is the result of ur...

Effect of Surface Preparation and Gas Flow on Nitrogen Atom Surface Recombination

NASA Technical Reports Server (NTRS)

Prok, George M.

1961-01-01

The effects of surface preparation and gas flow on the recombination of nitrogen atoms at copper and platinum surfaces were determined. Atoms were generated by an electrodeless 2450-megacycle-per-second discharge, and their concentration was measured by gas-phase titration with nitric oxide. Test surfaces were either vacuum-evaporated films or spheres machined from bulk metal and cemented around small glass-bead thermistors. Heat released by recombination was measured as the difference in electrical energy required to maintain a given thermistor temperature with and without a catalytic surface exposed. Recombination coefficients measured at flow velocities of 1120, 1790, 2250, and 3460 centimeters per second and at pressures of 0.42 and 0.59 millimeter of mercury showed that flow conditions had no effect. The results were also independent of atom concentration. A rough indication of the temperature dependence was obtained; it was greater for copper than for platinum. Platinum films deposited on platinum or on glass had the same activity - about 3 percent of the atoms impinging recombined. With copper, however, the glass substrate greatly reduced the percent of atoms recombining over that of a bulk copper substrate where 4 percent of the impinging atoms recombined. This effect could be overcome by depositing a second film on top of the first. Bulk metal samples were subjected to various surface treatments including polishing, degreasing with a chlorinated hydrocarbon, washing with nitric acid, and rinsing with water. Polished, degreased platinum had low activity compared to an evaporated film, but nitric acid treatment made it equivalent. Polished, degreased copper was only slightly less active than a copper film; nitric acid etching decreased the activity still further, probably by preferentially exposing facets of low catalytic efficiency.

Proton affinity of methyl nitrate - Less than proton affinity of nitric acid

NASA Technical Reports Server (NTRS)

Lee, Timothy J.; Rice, Julia E.

1992-01-01

Several state-of-the-art ab initio quantum mechanical methods were used to investigate the equilibrium structure, dipole moments, harmonic vibrational frequencies, and IR intensities of methyl nitrate, methanol, and several structures of protonated methyl nitrate, using the same theoretical methods as in an earlier study (Lee and Rice, 1992) of nitric acid. The ab initio results for methyl nitrate and methanol were found to be in good agreement with available experimental data. The proton affinity (PA) of methyl nitrate was calculated to be 176.9 +/-5 kcal/mol, in excellent agreement with the experimental value 176 kcal/mol obtained by Attina et al. (1987) and less than the PA value of nitric acid. An explanation of the discrepancy of the present results with those of an earlier study on protonated nitric acid is proposed.

Energetic particle-induced enhancements of stratospheric nitric acid

NASA Technical Reports Server (NTRS)

Aikin, Arthur C.

1994-01-01

Inclusion of complete ion chemistry in the calculation of minor species production during energetic particle deposition events leads to significant enhancement in the calculated nitric acid concentration during precipitation. An ionization rate of 1.2 x 10(exp 3)/cu cm/s imposed for 1 day increases HNO3 from 3 x 10(exp 5) to 6 x 10(exp 7)/cu cm at 50 km. With an ionization rate of 600 cu cm/s, the maximum HNO3 is 3 x 10(exp 7)/cu cm. Calculations which neglect negative ions predict the nitric acid will fall during precipitation events. The decay time for converting HNO3 into odd nitrogen and hydrogen is more than 1 day for equinoctial periods at 70 deg latitude. Examination of nitric acid data should yield important information on the magnitude and frequency of charged particle events.

Method for dissolving delta-phase plutonium

DOEpatents

Karraker, David G.

1992-01-01

A process for dissolving plutonium, and in particular, delta-phase plutonium. The process includes heating a mixture of nitric acid, hydroxylammonium nitrate (HAN) and potassium fluoride to a temperature between 40.degree. and 70.degree. C., then immersing the metal in the mixture. Preferably, the nitric acid has a concentration of not more than 2M, the HAN approximately 0.66M, and the potassium fluoride 0.1M. Additionally, a small amount of sulfamic acid, such as 0.1M can be added to assure stability of the HAN in the presence of nitric acid. The oxide layer that forms on plutonium metal may be removed with a non-oxidizing acid as a pre-treatment step.

[Studies on the oxidation reaction of octanol-2 with nitric acid by infrared spectroscopy].

PubMed

Zhang, G; Zhao, G; Wang, Y; Zhang, Q; Zhang, S; Lu, F

1998-04-01

In this paper, the reaction process of oxidation of octanol-2 with nitric acid has been studied by IR spectroscopy. It is found that the main components of non-sapoifiable matter are different in different oxidation degrees. The relation between oxidation products and the amount of nitric acid are investigated,the reaction mechanism has also been studied. Experimental results show that the oxidation process of octanol-2 is as follows: first, octanol-2 is oxidated to octanone-2, or to nitrate, nitrite and nitrile copmpounds, then these compounds are reoxidated to caproic acid in the meantime some by-products, such as valeric, enanthic acids are also found in oxidated products.

Determination of Chromium(III), Chromium(VI), and Chromium(III) acetylacetonate in water by ion-exchange disk extraction/metal furnace atomic absorption spectrometry

NASA Astrophysics Data System (ADS)

Kamakura, Nao; Inui, Tetsuo; Kitano, Masaru; Nakamura, Toshihiro

A new method for the separate determination of Chromium(III) (Cr(III)), Chromium(VI) (Cr(VI)), and Cr(III) acetylacetonate (Cr(acac)3) in water was developed using a cation-exchange extraction disk (CED) and an anion-exchange extraction disk (AED) combined with metal furnace atomic absorption spectrometry (MFAAS). A 100-mL water sample was adjusted to pH 5.6 and passed through the CED placed on the AED. Cr(acac)3 and Cr(III) were adsorbed on the CED, and Cr(VI) was adsorbed on the AED. The adsorbed Cr(acac)3 was eluted with 50 mL of carbon tetrachloride, followed by the elution of Cr(III) with 50 mL of 3 mol L- 1 nitric acid. Cr(VI) was eluted with 50 mL of 3 mol L- 1 nitric acid. The chemical species of Cr eluted from the CED with carbon tetrachloride was identified as Cr(acac)3 using infrared spectroscopy. The eluate of Cr(acac)3 was diluted to 100 mL with carbon tetrachloride, and those of Cr(III) and Cr(VI) were diluted to 100 mL with deionized water. All of the solutions were subsequently analyzed by MFAAS. The calibration curve for the Cr(acac)3 aqueous solutions exhibited good linearity in the range of 0.1 to 1 ng. The detection limit of Cr, which corresponded to three times the standard deviation (n = 10) of the blank values, was 20 pg. The recovery test for Cr(III), Cr(VI), and Cr(acac)3 exhibited desirable results (96.0%-107%) when 5 μg of each species (50 μg L- 1) was added to 100 mL water samples (i.e., tap water, rainwater, and bottled drinking water). In a humic acid solution, Cr(acac)3 was quantitatively recovered (103%), but Cr(III) and Cr(VI) exhibited poor recoveries (i.e., 84.8% and 78.4%, respectively).

Pharmacognostic Specification, Chlorogenic Acid Content, and In vitro Antioxidant Activities of Lonicera japonica Flowering Bud.

PubMed

Chaowuttikul, Chayanon; Palanuvej, Chanida; Ruangrungsi, Nijsiri

2017-01-01

Lonicera japonica Thunb. or Japanese Honeysuckle has been widely used in traditional medicine for antipyretic. To establish the pharmacognostic specification of L. japonica flowering bud in Thailand and to determine its chlorogenic acid content and in vitro antioxidant activities. Dried L. japonica flowering bud from 15 various herbal drugstores throughout Thailand were investigated for pharmacognostic specification. Their chlorogenic acid contents were quantitatively analyzed by thin layer chromatography (TLC) densitometry with winCATS software. The mobile phase for TLC development consisted of ethyl acetate: formic acid: acetic acid: water (10:1.1:1.1:2.6). Antioxidant activities were investigated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ferric ion reducing antioxidant power assay, nitric oxide scavenging assay, and β-carotene bleaching assays. Qualified L. japonica flowering bud in Thailand was presented that the contents of loss on drying, total ash, acid-insoluble ash, and water should not be >10.11%, 6.59%, 1.14%, and 10.82% by weight, respectively. The ethanol and water soluble extractive values should not be < 16.46% and 28.88% by weight, respectively. Chlorogenic acid content in L. japonica flowering bud was found to be 2.24 ± 0.50 g/100 g of crude drug. L. japonica flowering bud showed DPPH and nitric oxide scavenging activities as well as reducing power property. This pharmacognostic specification with special reference to the chlorogenic acid content can be used for quality control of L. japonica flowering bud in Thailand. The potential antioxidant of this crude drug was demonstrated in vitro . Pharmacognostic specification of Lonicera japonica flowering bud in Thailand has been establishedThe chlorogenic acid content has been quantified by thin layer chromatography-densitometryThe ethanolic extract of L. japonica flowering bud showed antioxidation potential, especially on reducing power property. Abbreviations Used: TLC: Thin layer chromatography, DPPH: 2,2-diphenyl-1-picrylhydrazyl, FRAP: Ferric ion Reducing Antioxidant Power, WHO: World Health Organization, ICH: International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use; LOD: Limit of detection; LOQ: Limit of quantitation; BHT: Butylated hydroxytoluene; FeSO 4 : Iron(II) sulfate; DMSO: Dimethyl sulfoxide; TPTZ: 2,4,6-tripyridyl-s-triazine.

A CHEMICAL METHOD OF TREATING FISSIONABLE MATERIAL

DOEpatents

Olson, C.M.

1959-09-01

One step of a process for separating plutonium from uranium and fission products is presented. A nitric acid solution containing these constituents is treated with formic acid to reduce simultaneously the plutonium to a valence state of not greater than +4 and destroy and eliminate the excess nitric acid.

75 FR 18830 - Agency Information Collection Activities; Submission to OMB for Review and Approval; Comment...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-13

... Approval; Comment Request; NSPS for Nitric Acid Plants AGENCY: Environmental Protection Agency (EPA... electronic docket, go to http://www.regulations.gov . Title: NSPS for Nitric Acid Plants (Renewal). ICR... acid plants which commenced construction, modification or reconstruction after August 17, 1971. Owners...

Stratospheric aircraft exhaust plume and wake chemistry studies

NASA Technical Reports Server (NTRS)

Miake-Lye, R. C.; Martinez-Sanchez, M.; Brown, R. C.; Kolb, C. E.; Worsnop, D. R.; Zahniser, M. S.; Robinson, G. N.; Rodriguez, J. M.; Ko, M. K. W.; Shia, R-L.

1992-01-01

This report documents progress to date in an ongoing study to analyze and model emissions leaving a proposed High Speed Civil Transport (HSCT) from when the exhaust gases leave the engine until they are deposited at atmospheric scales in the stratosphere. Estimates are given for the emissions, summarizing relevant earlier work (CIAP) and reviewing current propulsion research efforts. The chemical evolution and the mixing and vortical motion of the exhaust are analyzed to track the exhaust and its speciation as the emissions are mixed to atmospheric scales. The species tracked include those that could be heterogeneously reactive on the surfaces of the condensed solid water (ice) particles and on exhaust soot particle surfaces. Dispersion and reaction of chemical constituents in the far wake are studied with a Lagrangian air parcel model, in conjunction with a radiation code to calculate the net heating/cooling. Laboratory measurements of heterogeneous chemistry of aqueous sulfuric acid and nitric acid hydrates are also described. Results include the solubility of HCl in sulfuric acid which is a key parameter for modeling stratospheric processing. We also report initial results for condensation of nitric acid trihydrate from gas phase H2O and HNO3.

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; preparation procedure for aquatic biological material determined for trace metals

USGS Publications Warehouse

Hoffman, Gerald L.

1996-01-01

A method for the chemical preparation of tissue samples that are subsequently analyzed for 22 trace metals is described. The tissue-preparation procedure was tested with three National Institute of Standards and Technology biological standard reference materials and two National Water Quality Laboratory homogenized biological materials. A low-temperature (85 degrees Celsius) nitric acid digestion followed by the careful addition of hydrogen peroxide (30-percent solution) is used to decompose the biological material. The solutions are evaporated to incipient dryness, reconstituted with 5 percent nitric acid, and filtered. After filtration the solutions were diluted to a known volume and analyzed by inductively coupled plasma-mass spectrometry (ICP-MS), inductively coupled plasma-atomic emission spectrometry (ICP-AES), and cold vapor-atomic absorption spectrophotometry (CV-AAS). Many of the metals were determined by both ICP-MS and ICP-AES. This report does not provide a detailed description of the instrumental procedures and conditions used with the three types of instrumentation for the quantitation of trace metals determined in this study. Statistical data regarding recovery, accuracy, and precision for individual trace metals determined in the biological material tested are summarized.

Volatilization of iodine from nitric acid using peroxide

DOEpatents

Cathers, G.I.; Shipman, C.J.

1975-10-21

A method for removing radioactive iodine from nitric acid solution by adding hydrogen peroxide to the solution while concurrently holding the solution at the boiling point and distilling hydrogen iodide from the solution is reported.

Effects of nitric oxide and nitrogen dioxide on bacterial growth

NASA Technical Reports Server (NTRS)

Mancinelli, R. L.; Mckay, C. P.

1983-01-01

While it is generally thought that the bactericidal effects of NO and NO2 derive from their reaction with water to form nitrous and nitric acids (Shank et al., 1962), this appears to be true only at high concentrations. The data presented here suggest that at low NO and NO2 concentrations, acids are not present in high enough concentrations to act as toxic agents. Reference is made to a study by Grant et al. (1979), which found that exposing acid forest soil to 1 ppm of NO2 did not cause the soil pH to drop. The results presented here show that at low concentrations of NO and NO2, the NO is bacteriostatic for some organisms and not for others, whereas NO2 may protect some bacteria from the inhibitory effects of NO. Since it has been shown that bacteria can divide while airborne (Dimmick et al., 1979), the present results suggest that NO at the low concentrations found in the atmosphere can select for resistant bacteria in the air and affect the viable airborne bacterial population.

PROCESS OF SECURING PLUTONIUM IN NITRIC ACID SOLUTIONS IN ITS TRIVALENT OXIDATION STATE

DOEpatents

Thomas, J.R.

1958-08-26

>Various processes for the recovery of plutonium require that the plutonium be obtalned and maintained in the reduced or trivalent state in solution. Ferrous ions are commonly used as the reducing agent for this purpose, but it is difficult to maintain the plutonium in a reduced state in nitric acid solutions due to the oxidizing effects of the acid. It has been found that the addition of a stabilizing or holding reductant to such solution prevents reoxidation of the plutonium. Sulfamate ions have been found to be ideally suitable as such a stabilizer even in the presence of nitric acid.

The effects of liquid-phase oxidation of multiwall carbon nanotubes on their surface characteristics

NASA Astrophysics Data System (ADS)

Burmistrov, I. N.; Muratov, D. S.; Ilinykh, I. A.; Kolesnikov, E. A.; Godymchuk, A. Yu; Kuznetsov, D. V.

2016-01-01

The development of new sorbents based on nanostructured carbon materials recently became a perspective field of research. Main topic of current study is to investigate the effect of different regimes of multiwall carbon nanotubes (MWCNT) surface modification process on their structural characteristics. MWCNT samples were treated with nitric acid at high temperature. Structural properties were studied using low temperature nitrogen adsorption and acid-base back titration methods. The study showed that diluted nitric acid does not affect MWCNT structure. Concentrated nitric acid treatment leads to formation of 2.8 carboxylic groups per 1 nm2 of the sample surface.

Stabilization and Solidification of Nitric Acid Effluent Waste at Y-12

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Dileep; Lorenzo-Martin, Cinta

Consolidated Nuclear Security, LLC (CNS) at the Y-12 plant is investigating approaches for the treatment (stabilization and solidification) of a nitric acid waste effluent that contains uranium. Because the pH of the waste stream is 1-2, it is a difficult waste stream to treat and stabilize by a standard cement-based process. Alternative waste forms are being considered. In this regard, Ceramicrete technology, developed at Argonne National Laboratory, is being explored as an option to solidify and stabilize the nitric acid effluent wastes.

SEPARATION OF URANIUM, PLUTONIUM AND FISSION PRODUCTS

DOEpatents

Nicholls, C.M.; Wells, I.; Spence, R.

1959-10-13

The separation of uranium and plutonium from neutronirradiated uranium is described. The neutron-irradiated uranium is dissolved in nitric acid to provide an aqueous solution 3N in nitric acid. The fission products of the solution are extruded by treating the solution with dibutyl carbitol substantially 1.8N in nitric acid. The organic solvent phase is separated and neutralized with ammonium hydroxide and the plutonium reduced with hydroxylamine base to the trivalent state. Treatment of the mixture with saturated ammonium nitrate extracts the reduced plutonium and leaves the uranium in the organic solvent.

Separation and preconcentration of actinides from concentrated nitric acid by extraction chromatography in microsystems.

PubMed

Losno, Marion; Pellé, Julien; Marie, Mylène; Ferrante, Ivan; Brennetot, René; Descroix, Stéphanie; Mariet, Clarisse

2018-08-01

An original method of monolith impregnation in microsystem for the analysis of radionuclides in nitric acid is reported. Three microcolumns made of monolith poly(AMA-co-EDMA) were impregnated in COC microsystems. The robustness of the microsystems in nitric acid media until 8 M was demonstrated. High exchange capacity and affinity for tetravalent and hexavalent actinides in concentrated nitric media were obtained. The retention characteristics of the microcolumns impregnated by TBP, TBP-CMPO and DAAP were compared with those of the equivalent commercial particulate resins TBP™, TRU™ and UTEVA™ respectively. The separation of U, Th and Eu was validated in a classical microsystem and a procedure is proposed in a centrifugal microsystem. Copyright © 2018. Published by Elsevier B.V.

Effect of Extraction Conditions on the Saccharide (Neutral and Acidic) Composition of the Crude Pectic Extract from Various Agro-Industrial Residues.

PubMed

Babbar, Neha; Roy, Sandra Van; Wijnants, Marc; Dejonghe, Winnie; Caligiani, Augusta; Sforza, Stefano; Elst, Kathy

2016-01-13

The influence of different extraction methodologies was assessed on the composition of both neutral (arabinose, rhamnose, galactose) and acidic (galacturonic acid) pectic polysaccharides obtained from four agro-industrial residues, namely, berry pomace (BP), onion hulls (OH), pressed pumpkin (PP), and sugar beet pulp (SBP). For acidic pectic polysaccharides, the extraction efficiency was obtained as BP (nitric acid-assisted extraction, 2 h, 62.9%), PP (enzymatic-assisted extraction, 12 h, 75.0%), SBP (enzymatic-assisted extraction, 48 h, 89.8%; and nitric acid-assisted extraction, 4 h, 76.5%), and OH (sodium hexametaphosphate-assisted extraction, 0.5 h, 100%; and ammonium oxalate-assisted extraction, 0.5 h, 100%). For neutral pectic polysaccharides, the following results were achieved: BP (enzymatic-assisted extraction, 24 h, 85.9%), PP (nitric acid-assisted extraction, 6 h, 82.2%), and SBP (enzymatic assisted extraction, 48 h, 97.5%; and nitric acid-assisted extraction, 4 h, 83.2%). On the basis of the high recovery of pectic sugars, SBP and OH are interesting candidates for the further purification of pectin and production of pectin-derived products.

Free energy of formation of a crystal nucleus in incongruent solidification: Implication for modeling the crystallization of aqueous nitric acid droplets in polar stratospheric clouds

NASA Astrophysics Data System (ADS)

Djikaev, Yuri S.; Ruckenstein, Eli

2017-04-01

Using the formalism of classical thermodynamics in the framework of the classical nucleation theory, we derive an expression for the reversible work W* of formation of a binary crystal nucleus in a liquid binary solution of non-stoichiometric composition (incongruent crystallization). Applied to the crystallization of aqueous nitric acid droplets, the new expression more adequately takes account of the effects of nitric acid vapor compared to the conventional expression of MacKenzie, Kulmala, Laaksonen, and Vesala (MKLV) [J. Geophys. Res.: Atmos. 102, 19729 (1997)]. The predictions of both MKLV and modified expressions for the average liquid-solid interfacial tension σls of nitric acid dihydrate (NAD) crystals are compared by using existing experimental data on the incongruent crystallization of aqueous nitric acid droplets of composition relevant to polar stratospheric clouds (PSCs). The predictions for σls based on the MKLV expression are higher by about 5% compared to predictions based on our modified expression. This results in similar differences between the predictions of both expressions for the solid-vapor interfacial tension σsv of NAD crystal nuclei. The latter can be obtained by using the method based on the analysis of experimental data on crystal nucleation rates in aqueous nitric acid droplets; it exploits the dominance of the surface-stimulated mode of crystal nucleation in small droplets and its negligibility in large ones. Applying that method to existing experimental data, our expression for the free energy of formation provides an estimate for σsv of NAD in the range ≈92 dyn/cm to ≈100 dyn/cm, while the MKLV expression predicts it in the range ≈95 dyn/cm to ≈105 dyn/cm. The predictions of both expressions for W* become identical for the case of congruent crystallization; this was also demonstrated by applying our method for determining σsv to the nucleation of nitric acid trihydrate crystals in PSC droplets of stoichiometric composition.

Fact Sheet: Revisions to New Source Performance Standards (NSPS) for Nitric Acid Plants

EPA Pesticide Factsheets

This page contains a May 2012 fact sheet with information regarding the New Source Performance Standards (NSPS) for Nitric Acid Plants. This document provides a summary of the information for this NSPS.

Effect of nitric acid treatment on activated carbon derived from oil palm shell

NASA Astrophysics Data System (ADS)

Allwar, Allwar; Hartati, Retno; Fatimah, Is

2017-03-01

The primary object of this work is to study the effect of nitric acid on the porous and morphology structure of activated carbon. Production of activated carbon from oil palm shell was prepared with pyrolysis process at temperature 900°C and by introduction of 10 M nitric acid. Determination of surface area, pore volume and pore size distribution of activated carbon was conducted by the N2 adsorption-desorption isotherm at 77 K. Morphology structure and elemental micro-analysis of activated carbon were estimated by Scanning Electron Microscopy (SEM) and energy dispersive X-ray (EDX), respectively. The result shows that activated carbon after treating with nitric acid proved an increasing porous characteristics involving surface area, pore volume and pore size distribution. It also could remove the contaminants including metals and exhibit an increasing of pores and crevices all over the surface.

Statistical Modeling of Zr/Hf Extraction using TBP-D2EHPA Mixtures

NASA Astrophysics Data System (ADS)

Rezaeinejhad Jirandehi, Vahid; Haghshenas Fatmehsari, Davoud; Firoozi, Sadegh; Taghizadeh, Mohammad; Keshavarz Alamdari, Eskandar

2012-12-01

In the present work, response surface methodology was employed for the study and prediction of Zr/Hf extraction curves in a solvent extraction system using D2EHPA-TBP mixtures. The effect of change in the levels of temperature, nitric acid concentration, and TBP/D2EHPA ratio (T/D) on the Zr/Hf extraction/separation was studied by the use of central composite design. The results showed a statistically significant effect of T/D, nitric acid concentration, and temperature on the extraction percentage of Zr and Hf. In the case of Zr, a statistically significant interaction was found between T/D and nitric acid, whereas for Hf, both interactive terms between temperature and T/D and nitric acid were significant. Additionally, the extraction curves were profitably predicted applying the developed statistical regression equations; this approach is faster and more economical compared with experimentally obtained curves.

Acidic Peptizing Agent Effect on Anatase-Rutile Ratio and Photocatalytic Performance of TiO2 Nanoparticles

NASA Astrophysics Data System (ADS)

Mahmoud, Hatem A.; Narasimharao, Katabathini; Ali, Tarek T.; Khalil, Kamal M. S.

2018-02-01

TiO2 nanoparticles were synthesized from titanium isopropoxide by a simple peptization method using sulfuric, nitric, and acetic acids. The effect of peptizing acid on physicochemical and photocatalytic properties of TiO2 powders was studied. The structural properties of synthesized TiO2 powders were analyzed by using XRD, TEM, N2-physisorption, Raman, DR UV- vis, FTIR, and X-ray photoelectron spectroscopy techniques. The characterization results showed that acetic acid peptization facilitated the formation of pure anatase phase after thermal treatment at 500 °C; in contrast, nitric acid peptization led to a major rutile phase formation (67%). Interestingly, the sample peptized using sulfuric acid yielded 95% anatase and 5% rutile phases. The photocatalytic activity of synthesized TiO2 nanoparticles was evaluated for degradation of selected organic dyes (crystal violet, methylene blue, and p-nitrophenol) in aqueous solution. The results confirmed that the TiO2 sample peptized using nitric acid (with rutile and anatase phases in 3:1 ratio) offered the highest activity for degradation of organic dyes, although, TiO2 samples peptized using sulfuric acid and acetic acid possessed smaller particle size, higher band gap energy, and high surface area. Interestingly, TiO2 sample peptized with nitric acid possessed relatively high theoretical photocurrent density (0.545 mAcm-2) and pore diameter (150 Å), which are responsible for high electron-hole separation efficiency and diffusion and mass transportation of organic reactants during the photochemical degradation process. The superior activity of TiO2 sample peptized with nitric acid is due to the effective transfer of photogenerated electrons between rutile and anatase phases.

Electrochemistry and Spectroelectrochemistry of the Pu (III/IV) and (IV/VI) Couples in Nitric Acid Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lines, Amanda M.; Adami, Susan R.; Casella, Amanda J.

The solution chemistry of Pu in nitric acid is explored via electrochemistry and spectroelectrochemistry. By utilizing and comparing these techniques, an improved understanding of Pu behavior and its dependence on nitric acid concentration can be achieved. Here the Pu (III/IV) couple is characterized using cyclic voltammetry, square wave voltammetry, and a spectroelectrochemical Nernst step. Results indicate the formal reduction potential of the couple shifts negative with increasing acid concentration and reversible electrochemistry is no longer attainable above 6 M HNO3. Spectroelectrochemistry is also used to explore the irreversible oxidation of Pu(IV) to Pu(VI) and shine light on the mechanism andmore » acid dependence of the redox reaction.« less

[Ultrasound induced the formation of nitric oxide and nitrosonium ions in water and aqueous solutions].

PubMed

Stepuro, I I; Adamchuk, R I; Stepuro, V I

2004-01-01

Nitric oxide, nitrosonium ions, nitrites, and nitrates are formed in water saturated with air under the action of ultrasound. Nitrosonium ions react with water and hydrogen peroxide to form nitrites and nitrates in sonicated solution, correspondingly. Nitric oxide is practically completely released from sonicated water into the atmosphere and reacts with air oxygen, forming NOx compounds. The oxidation of nitric oxide in aqueous medium by hydroxyl radicals and dissolved oxygen is a minor route of the formation of nitrites and nitrates in ultrasonic field.

Enhanced solar evaporation of water from porous media, through capillary mediated forces and surface treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Canbazoglu, F. M.; Fan, B.; Kargar, A.

2016-08-15

The relative influence of the capillary, Marangoni, and hydrophobic forces in mediating the evaporation of water from carbon foam based porous media, in response to incident solar radiation, are investigated. It is indicated that inducing hydrophilic interactions on the surface, through nitric acid treatment of the foams, has a similar effect to reduced pore diameter and the ensuing capillary forces. The efficiency of water evaporation may be parameterized through the Capillary number (Ca), with a lower Ca being preferred. The proposed study is of much relevance to efficient solar energy utilization.

Acid rain and its ecological consequences.

PubMed

Singh, Anita; Agrawal, Madhoolika

2008-01-01

Acidification of rain-water is identified as one of the most serious environmental problems of transboundary nature. Acid rain is mainly a mixture of sulphuric and nitric acids depending upon the relative quantities of oxides of sulphur and nitrogen emissions. Due to the interaction of these acids with other constituents of the atmosphere, protons are released causing increase in the soil acidity Lowering of soil pH mobilizes and leaches away nutrient cations and increases availability of toxic heavy metals. Such changes in the soil chemical characteristics reduce the soil fertility which ultimately causes the negative impact on growth and productivity of forest trees and crop plants. Acidification of water bodies causes large scale negative impact on aquatic organisms including fishes. Acidification has some indirect effects on human health also. Acid rain affects each and every components of ecosystem. Acid rain also damages man-made materials and structures. By reducing the emission of the precursors of acid rain and to some extent by liming, the problem of acidification of terrestrial and aquatic ecosystem has been reduced during last two decades.

Perchlorate and Halogen-Free High Energy Dense Oxidizers (HEDO)

DTIC Science & Technology

2011-06-01

nitric acid indicate that the covalent oxalic acid dinitrate ester should be more stable than the ionic dinitronium oxalate . The following three...synthetic strategies were developed to generate compound 11 (Scheme 17). Strategy I is the nitration of anhydrous oxalic acid with nitric acid (100...temperatures (25 to –30 °C) and in all dry solvents used. Scheme 17: Synthetic strategies for the production of oxalic acid dinitrate ester (11

Improvement of Tissue Survival of Skin Flaps by 5α-Reductase Inhibitors: Possible Involvement of Nitric Oxide and Inducible Nitric Oxide Synthase

PubMed Central

Karimi, Ali Asghar; Ajami, Marjan; Asadi, Yasin; Aboutaleb, Nahid; Gorjipour, Fazel; Malekloo, Roya; Pazoki-Toroudi, Hamidreza

2015-01-01

Background: Skin flap grafting is a popular approach for reconstruction of critical skin and underlying soft tissue injuries. In a previous study, we demonstrated the beneficial effects of two 5α-reductase inhibitors, azelaic acid and finasteride, on tissue survival in a rat model of skin flap grafting. In the current study, we investigated the involvement of nitric oxide and inducible nitric oxide synthase (iNOS) in graft survival mediated by these agents. Methods: A number of 42 male rats were randomly allocated into six groups: 1, normal saline topical application; 2, azelaic acid (100 mg/flap); 3, finasteride (1 mg/flap); 4, injection of L-NG-nitroarginine methyl ester (L-NAME) (i.p., 20 mg/kg); 5, L-NAME (20 mg/kg, i.p.) + azelaic acid (100 mg/flap, topical); 6, L-NAME (20 mg/kg, i.p.) + finasteride (1 mg/flap, topical). Tissue survival, level of nitric oxide, and iNOS expression in groups were measured. Results: Our data revealed that azelaic acid and finasteride significantly increased the expression of iNOS protein and nitric oxide (NO) levels in graft tissue (P < 0.05). These increases in iNOS expression and NO level were associated with higher survival of the graft tissue. Conclusion: It appears that alterations of the NO metabolism are implicated in the azelaic acid- and finasteride-mediated survival of the skin flaps. PMID:25864816

Evaporation of iodine-containing off-gas scrubber solution

DOEpatents

Partridge, J.A.; Bosuego, G.P.

1980-07-14

Mercuric nitrate-nitric acid scrub solutions containing radioiodine may be reduced in volume without excessive loss of volatile iodine. The use of concentrated nitric acid during an evaporation process oxidizes the mercury-iodide complex to a less volatile mercuric iodate precipitate.

Trajectory Studies of Large HNO3-Containing PSC Particles in the Arctic: Evidence for the Role of NAT

NASA Technical Reports Server (NTRS)

McKinney, K. A.; Wennberg, P. O.; Dhaniyala, S.; Fahey, D. W.; Northway, M. J.; Kuenzi, K. F.; Kleinboehl, A.; Sinnhuber, M.; Kuellmann, H.; Bremer, H.;

Method for making an energetic material

DOEpatents

Fox, Robert V [Idaho Falls, ID

2008-03-18

A method for making trinitrotoluene is described, and which includes the steps of providing a source of aqueous nitric acid having a concentration of less than about 95% by weight; mixing a surfactant with the source of aqueous nitric acid so as to dehydrate the aqueous nitric acid to produce a source of nitronium ions; providing a supercritical carbon dioxide environment; providing a source of an organic material to be nitrated to the supercritical carbon dioxide environment; and controllably mixing the source or nitronium ions with the supercritical carbon dioxide environment to nitrate the organic material and produce trinitrotoluene.

Microstructure and Corrosion Behavior of Laser Melted 304L SS Weldment in Nitric Acid Medium

NASA Astrophysics Data System (ADS)

Suresh, Girija; Kishor, P. S. V. R. A.; Dasgupta, Arup; Upadhyay, B. N.; Mallika, C.; Kamachi Mudali, U.

2017-02-01

The manuscript presents the effect of laser surface melting on the corrosion property of 304L SS weldment in nitric acid medium. 304L SS weldment was prepared by gas tungsten arc welding process and subsequently laser surface melted using Nd:YAG laser. The microstructure and corrosion resistance of laser surface melted 304L SS weldment was evaluated and compared with that of 304L SS as-weldment and 304L SS base. Microstructural evaluation was carried out using optical and scanning electron microscopes attached with energy-dispersive x-ray spectroscopy. Corrosion investigations were carried out in 4 and 8 M nitric acid by potentiodynamic polarization technique. From the results, it was found that laser surface melting of the weldment led to chemical and microstructural homogeneities, accompanied by a substantial decrease in delta ferrite content, that enhanced the corrosion resistance of the weldment in 4 and 8 M nitric acid. However, the enhancement in the corrosion resistance was not substantial. The presence of small amount of delta ferrite (2-4 wt.%) in the laser surface melted specimens was found to be detrimental in nitric acid. X-ray photoelectron spectroscopy studies were carried out to investigate the composition of the passive film.

N-N bond formation in Ugi processes: from nitric acid to libraries of nitramines.

PubMed

Mercalli, Valentina; Nyadanu, Aude; Cordier, Marie; Tron, Gian Cesare; Grimaud, Laurence; El Kaim, Laurent

2017-02-09

The Ugi reaction has drawn considerable attention over the years leading to numerous libraries of heterocycles and various extensions changing the nature of the components of the coupling. We report here the use of nitric acid as carboxylic acids surrogates, displaying the first aminative Ugi-type reaction leading to nitramines.

Rapid cycling of reactive nitrogen in the marine boundary layer.

PubMed

Ye, Chunxiang; Zhou, Xianliang; Pu, Dennis; Stutz, Jochen; Festa, James; Spolaor, Max; Tsai, Catalina; Cantrell, Christopher; Mauldin, Roy L; Campos, Teresa; Weinheimer, Andrew; Hornbrook, Rebecca S; Apel, Eric C; Guenther, Alex; Kaser, Lisa; Yuan, Bin; Karl, Thomas; Haggerty, Julie; Hall, Samuel; Ullmann, Kirk; Smith, James N; Ortega, John; Knote, Christoph

2016-04-28

Nitrogen oxides are essential for the formation of secondary atmospheric aerosols and of atmospheric oxidants such as ozone and the hydroxyl radical, which controls the self-cleansing capacity of the atmosphere. Nitric acid, a major oxidation product of nitrogen oxides, has traditionally been considered to be a permanent sink of nitrogen oxides. However, model studies predict higher ratios of nitric acid to nitrogen oxides in the troposphere than are observed. A 'renoxification' process that recycles nitric acid into nitrogen oxides has been proposed to reconcile observations with model studies, but the mechanisms responsible for this process remain uncertain. Here we present data from an aircraft measurement campaign over the North Atlantic Ocean and find evidence for rapid recycling of nitric acid to nitrous acid and nitrogen oxides in the clean marine boundary layer via particulate nitrate photolysis. Laboratory experiments further demonstrate the photolysis of particulate nitrate collected on filters at a rate more than two orders of magnitude greater than that of gaseous nitric acid, with nitrous acid as the main product. Box model calculations based on the Master Chemical Mechanism suggest that particulate nitrate photolysis mainly sustains the observed levels of nitrous acid and nitrogen oxides at midday under typical marine boundary layer conditions. Given that oceans account for more than 70 per cent of Earth's surface, we propose that particulate nitrate photolysis could be a substantial tropospheric nitrogen oxide source. Recycling of nitrogen oxides in remote oceanic regions with minimal direct nitrogen oxide emissions could increase the formation of tropospheric oxidants and secondary atmospheric aerosols on a global scale.

Reductions in DNAPL Longevity through Biological Flux Enhancement

DTIC Science & Technology

2009-01-01

3 Phosphorus 2 Calcium 111 Magnesium 11 Sulfur 47 Bioavailable iron 31 Total iron 198 Porosity 0.32 Conductivity 0.97 mmohs cm-1 Organic...acetate, propionate, and lactate were analyzed by filtering aqueous samples (2.7 mL) through a syringe filter (0.22 μm) containing 0.3 M oxalic acid...acid Nitric acid, glycol, peroxides, permanganates Acetone Conc. nitric and sulfuric acids Ammonia, anhydrous Halogens, calcium hypochlorite (bleach

Investigation of effect of fluoride on corrosion of 2S-0 aluminum and 347 stainless steel in fuming nitric acid at 170 F

NASA Technical Reports Server (NTRS)

Feiler, Charles E; Morrell, Gerald

1954-01-01

The effect of small additions of fluoride on the corrosion of 2S-0 aluminum and 347 stainless steel by fuming nitric acid at 170 degrees F has been evaluated quantitatively by the determination of the weight loss of metal specimens immersed in the acid. The ratio of metal surface area to volume of acid was approximately 7.5 inch (superscript)-1 in all cases. It was found that for acids containing no fluorides the weight loss of aluminum was approximately 1/5 that of stainless steel. Addition of 1 percent fluoride ion to the acid reduced the weight loss of both metals to practically zero even after 26 days of exposure to the acid at 170 degrees F. The minimum quantity of fluoride ion required to inhibit corrosion was found to be approximately 0.25 and 0.5 percent for aluminum and stainless steel, respectively, in white fuming nitric acid and 0.5 and 1 percent in red fuming nitric acid (18 percent nitrogen dioxide). These fluoride percentages were based on the total weight of acid. Provided the concentration of fluoride ion was sufficient to inhibit corrosion, the source of these ions was immaterial. Additional information concerning the effect of fluorides on corrosion was obtained by measuring the electrode potentials of the metals against a platinum reference electrode.

Mercuric iodate precipitation from radioiodine-containing off-gas scrubber solution

DOEpatents

Partridge, Jerry A.; Bosuego, Gail P.

1982-01-01

Mercuric nitrate-nitric acid scrub solutions containing radioiodine may be reduced in volume without excessive loss of volatile iodine. The use of concentrated nitric acid during an evaporation process oxidizes the mercury-iodide complex to a less volatile mercuric iodate precipitate.

Evaluation of chemical constituents and antioxidant activity of coconut water (Cocus nucifera L.) and caffeic acid in cell culture.

PubMed

Santos, João L A; Bispo, Vanderson S; Filho, Adriano B C; Pinto, Isabella F D; Dantas, Lucas S; Vasconcelos, Daiane F; Abreu, Fabíula F; Melo, Danilo A; Matos, Isaac A; Freitas, Florêncio P; Gomes, Osmar F; Medeiros, Marisa H G; Matos, Humberto R

2013-01-01

Coconut water contains several uncharacterized substances and is widely used in the human consumption. In this paper we detected and quantified ascorbic acid and caffeic acid and total phenolics in several varieties of coconut using HPLS/MS/MS (25.8 ± 0.6 µg/mL and 1.078 ± 0.013 µg/mL and 99.7 µg/mL, respectively, in the green dwarf coconut water, or 10 mg and 539 µg and 39.8 mg for units of coconut consumed, 500 ± 50 mL). The antioxidant potential of four coconut varieties (green dwarf, yellow dwarf, red dwarf and yellow Malaysian) was compared with two industrialized coconut waters and the lyophilized water of the green dwarf variety. All varieties were effective in scavenging the DPPH radical (IC₅₀=73 µL) and oxide nitric (0.1 mL with an IP of 29.9%) as well as in inhibiting the in vitro production of thiobarbituric acid reactive substances (1 mL with an IP of 34.4%), highlighting the antioxidant properties of the green dwarf which it is the most common used. In cell culture, the green dwarf water was efficient in protecting against oxidative damages induced by hydrogen peroxide.

Laboratory and field studies of stratospheric aerosols: Phase changes under high supersaturation

NASA Technical Reports Server (NTRS)

Hallet, John

1991-01-01

It is well known that water in the form of isolated small droplets supercool as much as 40 C below their equilibrium melting point. Solutions similarly supercool (with respect to water) and supersaturate (with respect of the solute). Experiments are described in which bulk solutions typical of atmospheric aerosols (nitric acid, sulfuric acid, and hydrates; ammonium sulfate; ammonium bisulfate; sodium chloride) are supercooled and/or supersaturated and nucleated to initiate crystal growth. Supersaturation of 300 percent is readily attainable, with linear growth of crystals increasing roughly as (supercooling/supersaturation)sup 2. The implication of the experiments is that the situation of metastability in polar stratosphere clouds is very likely, with nucleation only occuring under a high degree of supercooling or supersaturation.

The 1977 intertropical convergence zone experiment

NASA Technical Reports Server (NTRS)

Poppoff, I. G. (Editor); Page, W. A. (Editor); Margozzi, A. P. (Editor)

1979-01-01

Data are presented from the 1977 Intertropical Convergence Zone (ITCZ) Experiment conducted in the Panama Canal Zone in July 1977. Measurements were made daily over a 16-day period when the ITCZ moved across the Canal Zone. Two aircraft (Learjet and U-2) flew daily and provided data from horizontal traverses at several altitudes to 21.3 km of ozone, temperature, pressure, water vapor, aerosols, fluorocarbons, methane, nitrous oxide, nitric oxide, and nitric acid. Balloonsondes flown four times per day provided data on ozone, wind fields, pressure, temperature, and humidities to altitudes near 30 km. Rocketsondes provided daily data to altitudes near 69 km. Satellite photography provided detailed cloud information. Descriptions of individual experiments and detailed compilations of all results are provided.

Accumulation of several heavy metals and lanthanides in mushrooms (Agaricales) from the Chicago region.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aruguete, D. M.; Aldstadt, J. H., III; Mueller, G. M.

1998-01-01

This study explored the differences in metal uptake in sporocarps of ectomycorrhizae-forming fungi relative to (1) fungal species; (2) collection location; (3) differential metal uptake and variation within single-species, single-area populations; and (4) mobile metal content of soil substrate for the fungi. In addition, this study examined levels of some of the lanthanides in these mushrooms, as lanthanide uptake in higher fungi has not been quantified to date. In 1995 and 1996, sporocarps from three species of ectomycorrhizal fungi (Amanita flavorubescens, Amanita rubescens, and Russula pectinatoides) were collected from Cowles Bog, Indiana Dunes National Lakeshore (near an industrial area) andmore » the Palos forest preserves (near a residential area). Soil was also collected from the Cowles Bog plots; metals were extracted from the soil, either with local Lake Michigan water or with nitric acid. These two extractions were meant to simulate the natural soil equilibrium concentrations of soluble metals and the maximum possible effects of any fungal chelating chemicals, respectively. An inductively coupled plasma mass spectrometer was used to analyze soil extracts and nitric acid digests of whole sporocarps for the target analytes. The metals found at elevated levels in the mushrooms included four of environmental interest (Ag, Cd, Ba, and Pb) and three lanthanides (La, Ce, and Nd). Significant differences in uptake of metals were observed between A. rubescens and R. pectinatoides, while A. rubescens and A. flavorubescens were not significantly different. With regard to location, more cadmium was found in Cowles Bog collections of A. rubescens, while Palos forest A. rubescens had more of the lanthanides and barium. Significant specimen-to-specimen variation occurred in all populations examined. Correlation analysis between pairs of trace elements within each sporocarp population revealed strong positive correlations between the lanthanides. Sporocarps concentrated more metal than was made available by the lake water extraction of soil and less metal than was made available by the nitric acid extraction of soil.« less

Multivariate Analysis for Quantification of Plutonium(IV) in Nitric Acid Based on Absorption Spectra

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lines, Amanda M.; Adami, Susan R.; Sinkov, Sergey I.

Development of more effective, reliable, and fast methods for monitoring process streams is a growing opportunity for analytical applications. Many fields can benefit from on-line monitoring, including the nuclear fuel cycle where improved methods for monitoring radioactive materials will facilitate maintenance of proper safeguards and ensure safe and efficient processing of materials. On-line process monitoring with a focus on optical spectroscopy can provide a fast, non-destructive method for monitoring chemical species. However, identification and quantification of species can be hindered by the complexity of the solutions if bands overlap or show condition-dependent spectral features. Plutonium (IV) is one example ofmore » a species which displays significant spectral variation with changing nitric acid concentration. Single variate analysis (i.e. Beer’s Law) is difficult to apply to the quantification of Pu(IV) unless the nitric acid concentration is known and separate calibration curves have been made for all possible acid strengths. Multivariate, or chemometric, analysis is an approach that allows for the accurate quantification of Pu(IV) without a priori knowledge of nitric acid concentration.« less

Antimicrobial and Physicochemical Characterization of Biodegradable, Nitric Oxide-Releasing Nanocellulose-Chitosan Packaging Membranes.

PubMed

Sundaram, Jaya; Pant, Jitendra; Goudie, Marcus J; Mani, Sudhagar; Handa, Hitesh

2016-06-29

Biodegradable composite membranes with antimicrobial properties consisting of nanocellulose fibrils (CNFs), chitosan, and S-nitroso-N-acetyl-d-penicillamine (SNAP) were developed and tested for food packaging applications. As a nitric oxide donor, SNAP was encapsulated into completely dispersed chitosan in 100 mL of 0.1 N acetic acid and was thoroughly mixed with CNFs to produce a composite membrane. The fabricated membranes had a uniform dispersion of chitosan and SNAP within the CNFs, which was confirmed through scanning electron microscopy (SEM) micrographs and a chemiluminescence nitric oxide analyzer. The membranes prepared without SNAP showed lower water vapor permeability than that of the membranes with SNAP. The addition of SNAP resulted in a decrease in Young's modulus for both two- and three-layer membrane configurations. Antimicrobial property evaluation of SNAP-incorporated membranes showed an effective zone of inhibition against bacterial strains of Enterococcus faecalis, Staphylococcus aureus, and Listeria monocytogenes and demonstrated its potential applications for food packaging.

Interference of oxygen, carbon dioxide, and water vapor on the analysis for oxides of nitrogen by chemiluminescence

NASA Technical Reports Server (NTRS)

Maahs, H. G.

1975-01-01

The interference of small concentrations (less than 4 percent by volume) of oxygen, carbon dioxide, and water vapor on the analysis for oxides of nitrogen by chemiluminescence was measured. The sample gas consisted primarily of nitrogen, with less than 100 parts per million concentration of nitric oxide, and with small concentrations of oxygen, carbon dioxide, and water vapor added. Results obtained under these conditions indicate that although oxygen does not measurably affect the analysis for nitric oxide, the presence of carbon dioxide and water vapor causes the indicated nitric oxide concentration to be too low. An interference factor - defined as the percentage change in indicated nitric oxide concentration (relative to the true nitric oxide concentration) divided by the percent interfering gas present - was determined for carbon dioxide to be -0.60 + or - 0.04 and for water vapor to be -2.1 + or - 0.3.

Study on reduction and back extraction of Pu(IV) by urea derivatives in nitric acid conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ye, G.A.; Xiao, S.T.; Yan, T.H.

2013-07-01

The reduction kinetics of Pu(IV) by hydroxyl-semicarbazide (HSC), hydroxyurea (HU) and di-hydroxyurea (DHU) in nitric acid solutions were investigated separately with adequate kinetic equations. In addition, counter-current cascade experiments were conducted for Pu split from U in nitric acid media using three kinds of reductant, respectively. The results show that urea derivatives as a kind of novel salt-free reductant can reduce Pu(IV) to Pu(III) rapidly in the nitric acid solutions. The stripping experimental results showed that Pu(IV) in the organic phase can be stripped rapidly to the aqueous phase by the urea derivatives, and the separation factors of plutonium /uraniummore » can reach more than 10{sup 4}. This indicates that urea derivatives is a kind of promising salt-free agent for uranium/plutonium separation. In addition, the complexing effect of HSC with Np(IV) was revealed, and Np(IV) can be back-extracted by HSC with a separation factor of about 20.« less

Solubility limits of dibutyl phosphoric acid in uranium-nitric acid solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pierce, R.A.

2000-01-04

The Savannah River Site has enriched uranium (EU) solution that has been stored since being purified in its solvent extraction processes. The concentrations in solution are approximately 6 g/L U and 0.1 M nitric acid. Residual tributylphosphate in solution has slowly hydrolyzed to form dibutyl phosphoric acid (HDBP) at concentrations averaging 30--50 mg/L. Dibutyl phosphoric acid, in turn, is in equilibrium with (HDBP){sub 2} and DBP{sup {minus}}. Uranium can form compounds with the dibutylphosphate ion (DBP{sup {minus}}) which have limited solubility, thereby creating a nuclear criticality safety issue. Literature reports and earlier SRTC tests have shown that it is feasiblemore » to precipitate U-DBP solid during the storage and processing of EU solutions. As a result, a series of solubility experiments were run at nitric acid concentrations from 0--4.0 M HNO{sub 3}, uranium at 0--90 g/L, and temperatures from 0--30 C. The data shows temperature and nitric acid concentration dependence consistent with what would be expected. With respect to uranium concentration, U-DBP solubility passes through a minimum between 6 and 12 g/L U at the acid concentrations and temperatures studied. However, the minimum shows a slight shift toward lower uranium concentrations at lower nitric acid concentrations. The shifts in solubility are strongly dependent upon the overall ionic strength of the solution. The data also reveal a shift to higher DBP solubility above 0.5 M HNO{sub 3} for both 6 g/L and 12 g/L uranium solutions. Analysis of U-DBP solids from the tests identified distinct differences between precipitates from less than 0.5 M solutions and those from greater than 4 M acid. Analyses identified UO{sub 2}(DBP){sub 2} as the dominant compound present at low acid concentrations in accordance with literature reports. As the acid concentration increases, the crystalline UO{sub 2}(DBP){sub 2} shows molecular substitutions and an increase in amorphous content.« less

Ursolic acid isolated from guava leaves inhibits inflammatory mediators and reactive oxygen species in LPS-stimulated macrophages.

PubMed

Kim, Min-Hye; Kim, Jin Nam; Han, Sung Nim; Kim, Hye-Kyeong

2015-06-01

Psidium guajava (guava) leaves have been frequently used for the treatment of rheumatism, fever, arthritis and other inflammatory conditions. The purpose of this study was to identify major anti-inflammatory compounds from guava leaf extract. The methanol extract and its hexane-, dichloromethane-, ethylacetate-, n-butanol- and water-soluble phases derived from guava leaves were evaluated to determine their inhibitory activity on nitric oxide (NO) production by RAW 264.7 cells stimulated with lipopolysaccharide (LPS). The methanol extract decreased NO production in a dose-dependent manner without cytotoxicity at a concentration range of 0-100 μg/mL. The n-butanol soluble phase was the most potent among the five soluble phases. Four compounds were isolated by reversed-phase HPLC from the n-butanol soluble phase and identified to be avicularin, guaijaverin, leucocyanidin and ursolic acid by their NMR spectra. Among these compounds, ursolic acid inhibited LPS-induced NO production in a dose-dependent manner without cytotoxity at a concentration range of 1-10 µM, but the other three compounds had no effect. Ursolic acid also inhibited LPS-induced prostaglandin E2 production. A western blot analysis showed that ursolic acid decreased the LPS-stimulated inducible nitric oxide synthase and cyclooxygenase protein levels. In addition, ursolic acid suppressed the production of intracellular reactive oxygen species in LPS-stimulated RAW 264.7 cells, as measured by flow cytometry. Taken together, these results identified ursolic acid as a major anti-inflammatory compound in guava leaves.

The redox chemistry of neptunium in γ-irradiated aqueous nitric acid in the presence of an organic phase

DOE PAGES

Mincher, Bruce J.; Precek, Martin; Paulenova, Alena

2015-10-17

The radiolytic changes in oxidation state for solutions of initially Np(V) and/or Np(VI) were investigated by gamma-irradiation in conjunction with UV/Vis spectroscopy of the aqueous phase. Samples were irradiated in varying concentrations of nitric acid, and with or without the presence of 30% TBP in dodecane. At short irradiation times Np(V) was oxidized to Np(VI), even in the presence of the organic phase. Upon the radiolytic production of sufficient amounts of nitrous acid, reduction of Np(VI) to Np(V) occurred in both phases. This was accompanied by stripping of the previously extracted Np(VI). Nitric acid concentrations of 6 M mitigated thismore » reduction.« less

The redox chemistry of neptunium in γ-irradiated aqueous nitric acid in the presence of an organic phase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mincher, Bruce J.; Precek, Martin; Paulenova, Alena

The radiolytic changes in oxidation state for solutions of initially Np(V) and/or Np(VI) were investigated by gamma-irradiation in conjunction with UV/Vis spectroscopy of the aqueous phase. Samples were irradiated in varying concentrations of nitric acid, and with or without the presence of 30% TBP in dodecane. At short irradiation times Np(V) was oxidized to Np(VI), even in the presence of the organic phase. Upon the radiolytic production of sufficient amounts of nitrous acid, reduction of Np(VI) to Np(V) occurred in both phases. This was accompanied by stripping of the previously extracted Np(VI). Nitric acid concentrations of 6 M mitigated thismore » reduction.« less

Chemical and spectral behavior of nitric acid in aqueous sulfuric acid solutions: Absorption spectrum and molar absorption coefficient of nitronium ion

NASA Astrophysics Data System (ADS)

Ershov, Boris G.; Panich, Nadezhda M.

2018-01-01

The chemical species formed from nitric acid in aqueous solutions of sulfuric acid (up to 18.0 mol L- 1) were studied by optical spectroscopy method. The concentration region of nitronium ion formation was identified and NO2+ ion absorption spectrum was measured (λmax ≤ 190 nm and ε190 = 1040 ± 50 mol- 1 L cm- 1).

Alternative to Nitric Acid Passivation Project Overview

NASA Technical Reports Server (NTRS)

Lewis, Pattie L.

2013-01-01

The standard practice for protection of stainless steel is a process called passivation. This procedure results in the formation of a metal oxide layer to prevent corrosion. Typical passivation procedures call for the use of nitric acid which exhibits excellent corrosion performance; however, there are a number of environmental, worker safety, and operational issues associated with its use. The longtime military specification for the passivation of stainless steel was cancelled in favor of newer specifications which allow for the use of citric acid in place of nitric acid. Citric acid offers a variety of benefits that include increased safety for personnel, reduced environmental impact, and reduced operational costs. There have been few studies, however, to determine whether citric acid is an acceptable alternative for NASA and DoD. This paper details activities to date including development of the joint test plan, on-going and planned testing, and preliminary results.

Differentiation among Multiple Sources of Anthropogenic Nitrate in a Complex Groundwater System using Dual Isotope Systematics: A case study from Mortandad Canyon, New Mexico

NASA Astrophysics Data System (ADS)

Larson, T. E.; Perkins, G.; Longmire, P.; Heikoop, J. M.; Fessenden, J. E.; Rearick, M.; Fabyrka-Martin, J.; Chrystal, A. E.; Dale, M.; Simmons, A. M.

2009-12-01

The groundwater system beneath Los Alamos National Laboratory has been affected by multiple sources of anthropogenic nitrate contamination. Average NO3-N concentrations of up to 18.2±1.7 mg/L have been found in wells in the perched intermediate aquifer beneath one of the more affected sites within Mortandad Canyon. Sources of nitrate potentially reaching the alluvial and intermediate aquifers include: (1) sewage effluent, (2) neutralized nitric acid, (3) neutralized 15N-depleted nitric acid (treated waste from an experiment enriching nitric acid in 15N), and (4) natural background nitrate. Each of these sources is unique in δ18O and δ15N space. Using nitrate stable isotope ratios, a mixing model for the three anthropogenic sources of nitrate was established, after applying a linear subtraction of the background component. The spatial and temporal variability in nitrate contaminant sources through Mortandad Canyon is clearly shown in ternary plots. While microbial denitrification has been shown to change groundwater nitrate stable isotope ratios in other settings, the redox potential, relatively high dissolved oxygen content, increasing nitrate concentrations over time, and lack of observed NO2 in these wells suggest minimal changes to the stable isotope ratios have occurred. Temporal trends indicate that the earliest form of anthropogenic nitrate in this watershed was neutralized nitric acid. Alluvial wells preserve a trend of decreasing nitrate concentrations and mixing models show decreasing contributions of 15N-depleted nitric acid. Nearby intermediate wells show increasing nitrate concentrations and mixing models indicate a larger component derived from 15N-depleted nitric acid. These data indicate that the pulse of neutralized 15N-depleted nitric acid that was released into Mortandad Canyon between 1986 and 1989 has infiltrated through the alluvial aquifer and is currently affecting two intermediate wells. This hypothesis is consistent with previous research suggesting that the perched intermediate aquifers in the Mortandad Canyon watershed are recharged locally from the overlying alluvial aquifers.

LITERATURE REVIEW OF BORIC ACID SOLUBILITY DATA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crapse, K.; Kyser, E.

2011-09-22

A new solvent system is being evaluated for use in the Modular Caustic-Side Solvent Extraction Unit (MCU) and in the Salt Waste Processing Facility (SWPF). The new system replaces the current dilute nitric acid strip solution with 0.01 M boric acid. This literature study is performed to determine if there is a potential for boric acid to crystallize in the lines with emphasis on the transfer lines to the Defense Waste Processing Facility. This report focuses on the aqueous phase chemistry of boric acid under conditions relevant to MCU and SWPF. Operating and transfer conditions examined for the purpose ofmore » this review include temperatures between 13 C (McLeskey, 2008) and 45 C (Fondeur, 2007) and concentrations from 0 to 3M in nitric acid as well as exposure of small amounts of entrained boric acid in the organic phase to the sodium hydroxide caustic wash stream. Experiments were also conducted to observe any chemical reactions and off-gas generation that could occur when 0.01 M boric acid solution mixes with 3 M nitric acid solution and vice versa. Based on the low concentration (0.01M) of boric acid in the MCU/SWPF strip acid and the moderate operating temperatures (13 C to 45 C), it is unlikely that crystallization of boric acid will occur in the acid strip solution under process or transfer conditions. Mixing experiments of boric and nitric acid show no measurable gas generation (< 1 cc of gas per liter of solution) under similar process conditions.« less

Rapid, quantitative determination of bacteria in water. [adenosine triphosphate

NASA Technical Reports Server (NTRS)

Chappelle, E. W.; Picciolo, G. L.; Thomas, R. R.; Jeffers, E. L.; Deming, J. W. (Inventor)

1978-01-01

A bioluminescent assay for ATP in water borne bacteria is made by adding nitric acid to a water sample with concentrated bacteria to rupture the bacterial cells. The sample is diluted with sterile, deionized water, then mixed with a luciferase-luciferin mixture and the resulting light output of the bioluminescent reaction is measured and correlated with bacteria present. A standard and a blank also are presented so that the light output can be correlated to bacteria in the sample and system noise can be substracted from the readings. A chemiluminescent assay for iron porphyrins in water borne bacteria is made by adding luminol reagent to a water sample with concentrated bacteria and measuring the resulting light output of the chemiluminescent reaction.

40 CFR 98.226 - Data reporting requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... reporting year that missing data procedures were followed to measure nitric acid production (months). (m) If... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Data reporting requirements. 98.226... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Nitric Acid Production § 98.226 Data reporting requirements...

The Consistency of Isotopologues of Ambient Atmospheric Nitric Acid in Passively Collected Samples

NASA Astrophysics Data System (ADS)

Bell, M. D.; Sickman, J. O.; Bytnerowicz, A.; Padgett, P.; Allen, E. B.

2012-12-01

Anthropogenic sources of nitrogen oxides have previously been shown to have distinctive isotopic signatures of oxygen and nitrogen. Nylon filters are currently used in passive sampling arrays to measure ambient atmospheric nitric acid concentrations and estimate deposition rates. This experiment measured the ability of nylon filters to consistently collect isotopologues of atmospheric nitric acid in the same ratios as they are present in the atmosphere. Samplers were deployed in continuous stirred tank reactors (CSTR) and at field sites across a nitrogen deposition gradient in Southern California. Filters were exposed over a four week period with individual filters being subjected to 1-4 week exposure times. Extracted nitric acid were measured for δ18O and δ15N ratios and compared for consistency based on length of exposure and amount of HNO3 collected. Filters within the CSTRs collected HNO3 at a consistent rate in both high and low concentration chambers. After two weeks of exposure, the mean δ18O values were within 0.5‰ of the δ18O of the source HNO3 solution. The mean of all weekly exposures were within 0.5‰ of the δ15N of the source solution, but after three weeks, the mean δ15N of adsorbed HNO3 was within 0.2‰. As the length of the exposure increased, the variability of measured delta values decreased for both elements. The field samplers collected HNO3 consistent with previously measured values along a deposition gradient. The mean δ18O at high deposition sites was 52.2‰ compared to 35.7‰ at the low deposition sites. Mean δ15N values were similar at all sites across the deposition gradient. Due to precipitation events occurring during the exposure period, the δ15N and δ18O of nitric acid were highly variable at all field sites. At single sites, changes in δ15N and δ18O were negatively correlated, consistent with two-sourcing mixing dynamics, but the slope of the regressions differed between high and low deposition sites. Anthropogenic sources of atmospheric nitric acid accounted for 58% of the atmospheric nitric acid at the high deposition sites and 36.5% of the atmospheric nitric acid at the low deposition sites. The nylon filters proved to be an effective means of collecting isotopologues of HNO3 consistent with atmospheric concentrations. A length of the exposure of two weeks stabilizes isotopologue composition and minimizes the chance of variable weather events altering atmospheric values.

NEPTUNIUM SOLVENT EXTRACTION PROCESS

DOEpatents

Dawson, L.R.; Fields, P.R.

1959-10-01

The separation of neptunium from an aqueous solution by solvent extraction and the extraction of neptunium from the solvent solution are described. Neptunium is separated from an aqueous solution containing tetravalent or hexavalent neptunium nitrate, nitric acid, and a nitrate salting out agent, such as sodium nitrate, by contacting the solution with an organic solvent such as diethyl ether. Subsequently, the neptunium nitrate is extracted from the organic solvent extract phase with water.

SEPARATION OF SCANDIUM VALUES FORM IRON VALUES BY SOLVENT EXTRACTION

DOEpatents

Kuhlman, C.W. Jr.; Lang, G.P.

1961-12-19

A process is given for separating scandium from trivalent iron values. In this process, an aqueous nitric acid solution is contacted with a water- immiscible alkyl phosphate solution, the aqueous solution containing the values to be separated, whereby the scandium is taken up by the alkyl phosphate. The aqueous so1ution is preferably saturated with magnesium nitrate to retain the iron in the aqueous solution. (AEC)

Recycling of CdTe photovoltaic waste

DOEpatents

Goozner, Robert E.; Long, Mark O.; Drinkard, Jr., William F.

1999-01-01

A method for extracting and reclaiming metals from scrap CdTe photovoltaic cells and manufacturing waste by leaching the waste with a leaching solution comprising nitric acid and water, skimming any plastic material from the top of the leaching solution, separating the glass substrate from the liquid leachate and electrolyzing the leachate to separate Cd from Te, wherein the Te is deposits onto a cathode while the Cd remains in solution.

Lidar Temperature Measurements During the SOLVE Campaign and the Absence of PSCs from Regions of Very Cold Air

NASA Technical Reports Server (NTRS)

Burris, John; McGee, Thomas; Hoegy, Walt; Newman, Paul; Lait, Leslie; Twigg, Laurence; Sumnicht, Grant; Heaps, William; Hostetler, Chris; Neuber, Roland;

Spectroscopic and first-principles calculation studies of the chemical forms of palladium ion in nitric acid solution for development of disposal of high-level radioactive nuclear wastes

NASA Astrophysics Data System (ADS)

Watanabe, Shinta; Sato, Toshikazu; Yoshida, Tomoko; Nakaya, Masato; Yoshino, Masahito; Nagasaki, Takanori; Inaba, Yusuke; Takeshita, Kenji; Onoe, Jun

2018-04-01

We have investigated the chemical forms of palladium (Pd) ion in nitric acid solution, using XAFS/UV-vis spectroscopic and first-principles methods in order to develop the disposal of high-level radioactive nuclear liquid wastes (HLLW: radioactive metal ions in 2 M nitric acid solution). The results of theoretical calculations and XAFS/UV-vis spectroscopy indicate that Pd is a divalent ion and forms a square-planar complex structure coordinated with four nitrate ions, [Pd(NO3)4]2-, in nitric acid solution. This complex structure is also thermodynamically predicted to be most stable among complexes [Pd(H2O)x(NO3)4-x]x-2 (x = 0-4). Since the overall feature of UV-vis spectra of the Pd complex was independent of nitric acid concentration in the range 1-6 M, the structure of the Pd complex remains unchanged in this range. Furthermore, we examined the influence of γ-ray radiation on the [Pd(NO3)4]2- complex, using UV-vis spectroscopy, and found that UV-vis spectra seemed not to be changed even after 1.0 MGy irradiation. This implies that the Pd complex structure will be still stable in actual HLLW. These findings obtained above are useful information to develop the vitrification processes for disposal of HLLW.

Antidepressant-like effect of folic acid: Involvement of NMDA receptors and L-arginine-nitric oxide-cyclic guanosine monophosphate pathway.

PubMed

Brocardo, Patrícia de Souza; Budni, Josiane; Lobato, Kelly Ribas; Kaster, Manuella Pinto; Rodrigues, Ana Lúcia S

2008-11-19

Antidepressant-like activity of folic acid in forced swimming test and in the tail suspension test was demonstrated previously by our group. In this study we investigated the involvement of N-methyl-d-aspartate (NMDA) receptors and l-arginine-nitric oxide (NO)-cyclic guanosine monophosphate pathway in its antidepressant-like effect in the forced swimming test in mice. The antidepressant-like effect of folic acid (10 nmol/site, i.c.v.) was prevented by the pretreatment of mice with NMDA (0.1 pmol/site, i.c.v.), l-arginine (750 mg/kg, i.p., substrate for nitric oxide synthase), S-nitroso-N-acetyl-penicillamine (SNAP, 25 microg/site, i.c.v, a NO donor) or sildenafil (5 mg/kg, i.p., phosphodiesterase 5 inhibitor). The administration of 7-nitroindazole (25 and 50 mg/kg, i.p., a specific neuronal nitric oxide synthase (nNOS) inhibitor) or methylene blue (20 mg/kg, i.p., direct inhibitor of both nitric oxide synthase and soluble guanylate cyclase) in combination with a sub-effective dose of folic acid (1 nmol/site, i.c.v.) reduced the immobility time in the FST as compared with either drug alone. Together the results suggest that the antidepressant-like effect of folic acid in the forced swimming test is dependent on an inhibition of either NMDA receptors or NO and cGMP synthesis.

White Paper on Potential Hazards Associated with Contaminated Cheesecloth Exposed to Nitric Acid Solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hypes, Philip A.

This white paper addresses the potential hazards associated with waste cheesecloth that has been exposed to nitric acid solutions. This issue was highlighted by the cleanup of a 100 ml leak of aqueous nitric acid solution containing Heat Source (HS) plutonium on 21 June 2016. Nitration of cellulosic material is a well-understood process due to industrial/military applications of the resulting material. Within the Department of Energy complex, nitric acids have been used extensively, as have cellulosic wipes. If cellulosic materials are nitrated, the cellulosic material can become ignitable and in extreme cases, reactive. We have chemistry knowledge and operating experiencemore » to support the conclusion that all current wastes are safe and compliant. There are technical questions worthy of further experimental evaluation. An extent of condition evaluation has been conducted back to 2004. During this time period there have been interruptions in the authorization to use cellulosic wipes in PF-4. Limited use has been authorized since 2007 (for purposes other than spill cleanup), so our extent of condition includes the entire current span of use. Our evaluation shows that there is no indication that process spills involving high molarity nitric acid were cleaned up with cheesecloth since 2007. The materials generated in the 21 June leak will be managed in a safe manner compliant with all applicable requirements.« less

Corrosion property of 9Cr-ODS steel in nitric acid solution for spent nuclear fuel reprocessing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takeuchi, M.; Koizumi, T.; Inoue, M.

2013-07-01

Corrosion tests of oxide dispersion strengthened with 9% Cr (9Cr-ODS) steel, which is one of the desirable materials for cladding tube of sodium-cooled fast reactors, in pure nitric acid solution, spent FBR fuel solution, and its simulated solution were performed to understand the corrosion behavior in a spent nuclear fuel reprocessing. In this study, the 9Cr-ODS steel with lower effective chromium content was evaluated to understand the corrosion behavior conservatively. As results, the tube-type specimens of the 9Cr-ODS steels suffered severe weight loss owing to active dissolution at the beginning of the immersion test in pure nitric acid solution inmore » the range from 1 to 3.5 M. In contrast, the weight loss was decreased and they showed a stable corrosion in the higher nitric acid concentration, the dissolved FBR fuel solution, and its simulated solution by passivation. The corrosion rates of the 9Cr-ODS steel in the dissolved FBR fuel solution and its simulated solution were 1-2 mm/y and showed good agreement with each other. The passivation was caused by the shift of corrosion potential to noble side owing to increase in nitric acid concentration or oxidative ions in the dissolved FBR fuel solution and the simulated spent fuel solution. (authors)« less

Reduction of pertechnetate by acetohydroxamic acid: Formation of [TcNO(AHA)2(H2O)]+ and implications for the UREX process.

DOE Office of Scientific and Technical Information (OSTI.GOV)

1Harry Reid Center for Environmental Studies, Nuclear Science and Technology Division, University of Nevada, Las Vegas, Las Vegas, NV, 89154-4006; Gong, Cynthia-May S; Poineau, Frederic

2008-02-26

Reductive nitrosylation and complexation of ammonium pertechnetate by acetohydroxamic acid has been achieved in aqueous nitric and perchloric acid solutions. The kinetics of the reaction depend on the relative concentrations of the reaction components and are accelerated at higher temperatures. The reaction does not occur unless conditions are acidic. Analysis of the x-ray absorption fine structure spectroscopic data is consistent with a pseudo-octahedral geometry with the linear Tc-N-O bond typical of technetium nitrosyl compounds, and electron spin resonance spectroscopy is consistent with a the d{sup 5} Tc(II) nitrosyl complex. The nitrosyl source is generally AHA, but may be augmented bymore » products of reaction with nitric acid. The resulting low-valency trans-aquonitrosyl(diacetohydroxamic)-technetium(II) complex (1) is highly soluble in water, extremely hydrophilic, and is not extracted by tri-n-butylphosphate in a dodecane diluent. Its extraction properties are not pH-dependent; titration studies indicate a single species from pH 4.5 down to -0.6 (calculated). This molecule is resistant to oxidation by H{sub 2}O{sub 2}, even at high pH, and can undergo substitution to form other technetium nitrosyl complexes. The formation of 1 may strongly impact the fate of technetium in the nuclear fuel cycle.« less

PROCESS FOR EXTRACTING NEPTUNIUM AND PLUTONIUM FROM NITRIC ACID SOLUTIONS OF SAME CONTAINING URANYL NITRATE WITH A TERTIARY AMINE

DOEpatents

Sheppard, J.C.

1962-07-31

A process of selectively extracting plutonium nitrate and neptunium nitrate with an organic solution of a tertiary amine, away from uranyl nitrate present in an aqueous solution in a maximum concentration of 1M is described. The nitric acid concentration is adjusted to about 4M and nitrous acid is added prior to extraction. (AEC)

Integrated Computational and Experimental Protocol for Understanding Rh(III) Speciation in Hydrochloric and Nitric Acid Solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samuels, Alex C.; Boele, Cherilynn A.; Bennett, Kevin T.

2014-12-01

A combined experimental and theoretical approach has investigated the complex speciation of Rh(III) in hydrochloric and nitric acid media, as a function of acid concentration. This has relevance to the separation and isolation of Rh(III) from dissolved spent nuclear fuel, which is an emergent and attractive alternative source of platinum group metals, relative to traditional mining efforts.

Chemical Kinetics Interpretation of Hypergolicity of Ionic Liquid-Based Systems

DTIC Science & Technology

2009-04-01

acid (WFNA) mixtures 6 4. Thermochemistry of imidazoles, triazoles and tetrazoles 8 5. Thermochemistry of compounds formed...reactivity of gaseous mixtures formed above ionic liquids (ILs) when mixed with white fuming nitric acid (WFNA). After a general introduction on the...replacement for NTO is also of interest but probably less crucial. For instance, NTO could be replaced by nitric acid (or by any other suitable

Material compatibility evaluation for DWPF nitric-glycolic acid-literature review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mickalonis, J.; Skidmore, E.

2013-06-01

Glycolic acid is being evaluated as an alternative for formic and nitric acid in the DWPF flowsheet. Demonstration testing and modeling for this new flowsheet has shown that glycolic acid and glycolate has a potential to remain in certain streams generated during the production of the nuclear waste glass. A literature review was conducted to assess the impact of glycolic acid on the corrosion of the materials of construction for the DWPF facility as well as facilities downstream which may have residual glycolic acid and glycolates present. The literature data was limited to solutions containing principally glycolic acid.

Pharmacognostic Specification, Chlorogenic Acid Content, and In vitro Antioxidant Activities of Lonicera japonica Flowering Bud

PubMed Central

Chaowuttikul, Chayanon; Palanuvej, Chanida; Ruangrungsi, Nijsiri

2017-01-01

Background: Lonicera japonica Thunb. or Japanese Honeysuckle has been widely used in traditional medicine for antipyretic. Objective: To establish the pharmacognostic specification of L. japonica flowering bud in Thailand and to determine its chlorogenic acid content and in vitro antioxidant activities. Materials and Methods: Dried L. japonica flowering bud from 15 various herbal drugstores throughout Thailand were investigated for pharmacognostic specification. Their chlorogenic acid contents were quantitatively analyzed by thin layer chromatography (TLC) densitometry with winCATS software. The mobile phase for TLC development consisted of ethyl acetate: formic acid: acetic acid: water (10:1.1:1.1:2.6). Antioxidant activities were investigated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ferric ion reducing antioxidant power assay, nitric oxide scavenging assay, and β-carotene bleaching assays. Results: Qualified L. japonica flowering bud in Thailand was presented that the contents of loss on drying, total ash, acid-insoluble ash, and water should not be >10.11%, 6.59%, 1.14%, and 10.82% by weight, respectively. The ethanol and water soluble extractive values should not be < 16.46% and 28.88% by weight, respectively. Chlorogenic acid content in L. japonica flowering bud was found to be 2.24 ± 0.50 g/100 g of crude drug. L. japonica flowering bud showed DPPH and nitric oxide scavenging activities as well as reducing power property. Conclusion: This pharmacognostic specification with special reference to the chlorogenic acid content can be used for quality control of L. japonica flowering bud in Thailand. The potential antioxidant of this crude drug was demonstrated in vitro. SUMMARY Pharmacognostic specification of Lonicera japonica flowering bud in Thailand has been establishedThe chlorogenic acid content has been quantified by thin layer chromatography-densitometryThe ethanolic extract of L. japonica flowering bud showed antioxidation potential, especially on reducing power property. Abbreviations Used: TLC: Thin layer chromatography, DPPH: 2,2-diphenyl-1-picrylhydrazyl, FRAP: Ferric ion Reducing Antioxidant Power, WHO: World Health Organization, ICH: International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use; LOD: Limit of detection; LOQ: Limit of quantitation; BHT: Butylated hydroxytoluene; FeSO4: Iron(II) sulfate; DMSO: Dimethyl sulfoxide; TPTZ: 2,4,6-tripyridyl-s-triazine. PMID:28539735

METHOD OF DISSOLVING URANIUM METAL

DOEpatents

Slotin, L.A.

1958-02-18

This patent relates to an economicai means of dissolving metallic uranium. It has been found that the addition of a small amount of perchloric acid to the concentrated nitric acid in which the uranium is being dissolved greatly shortens the time necessary for dissolution of the metal. Thus the use of about 1 or 2 percent of perchioric acid based on the weight of the nitric acid used, reduces the time of dissolution of uranium by a factor of about 100.

Nitric Oxide Mediates the Hormonal Control of Crassulacean Acid Metabolism Expression in Young Pineapple Plants1[W][OA

PubMed Central

Freschi, Luciano; Rodrigues, Maria Aurineide; Domingues, Douglas Silva; Purgatto, Eduardo; Van Sluys, Marie-Anne; Magalhaes, Jose Ronaldo; Kaiser, Werner M.; Mercier, Helenice

2010-01-01

Genotypic, developmental, and environmental factors converge to determine the degree of Crassulacean acid metabolism (CAM) expression. To characterize the signaling events controlling CAM expression in young pineapple (Ananas comosus) plants, this photosynthetic pathway was modulated through manipulations in water availability. Rapid, intense, and completely reversible up-regulation in CAM expression was triggered by water deficit, as indicated by the rise in nocturnal malate accumulation and in the expression and activity of important CAM enzymes. During both up- and down-regulation of CAM, the degree of CAM expression was positively and negatively correlated with the endogenous levels of abscisic acid (ABA) and cytokinins, respectively. When exogenously applied, ABA stimulated and cytokinins repressed the expression of CAM. However, inhibition of water deficit-induced ABA accumulation did not block the up-regulation of CAM, suggesting that a parallel, non-ABA-dependent signaling route was also operating. Moreover, strong evidence revealed that nitric oxide (NO) may fulfill an important role during CAM signaling. Up-regulation of CAM was clearly observed in NO-treated plants, and a conspicuous temporal and spatial correlation was also evident between NO production and CAM expression. Removal of NO from the tissues either by adding NO scavenger or by inhibiting NO production significantly impaired ABA-induced up-regulation of CAM, indicating that NO likely acts as a key downstream component in the ABA-dependent signaling pathway. Finally, tungstate or glutamine inhibition of the NO-generating enzyme nitrate reductase completely blocked NO production during ABA-induced up-regulation of CAM, characterizing this enzyme as responsible for NO synthesis during CAM signaling in pineapple plants. PMID:20147491

Houttuynia cordata Extract Improves Physical Endurance Performance by Regulating Endothelial Production of Nitric Oxide.

PubMed

Yang, Ui-Jeong; Maeng, Hyojin; Park, Tae-Sik; Shim, Soon-Mi

2015-09-01

Vascular function is mediated by various regulatory molecules, including endothelial nitric oxide (NO), which regulates the vasodilation of smooth muscle cells. We investigated whether standardized Houttuynia cordata extract (SHCE) could improve physical endurance performance by regulating the endothelial production of NO. For the standardization of Houttuynia cordata (HC) extract, its bioactive components were identified and quantified using ultraperformance liquid chromatography-mass spectrometry. Bioaccessibility and biological activity were measured by the in vitro digestion model system and free radical scavenging capacity, respectively. The vascular function in the endothelium was assessed by the phosphorylation of endothelial nitric oxide synthase (eNOS). A preliminary clinical trial was carried out to assess the physical endurance performance. HC extract was standardized to bioactive components, including chlorogenic acid, rutin, and quercitrin, with the concentration of 5.53, 6.09, and 16.15 mg from 1 g of dry weight, respectively. Bioaccessibility was 33.17%, 31.67%, and 11.18% for chlorogenic acid, rutin, and quercitrin, respectively. Antioxidant activities of SHCE were expressed as vitamin C equivalent antioxidant capacity in 55.81 and 17.23 mg/g of HC extract using ABTS and DPPH scavenging assay, respectively. In human aortic endothelial cells, insulin-mediated phosphorylation of eNOS was increased by SHCE in the presence of palmitate. However, the expression of blood pressure-regulating genes was not altered. The level of blood lactate concentration and the heart rate of subjects who drank SHCE were lower than those of subjects who drank plain water. Oxygen uptake from subjects drinking SHCE was slightly higher than that from those who drank plain water. This study demonstrated that SHCE decreased heart rate and blood lactate, increased oxygen uptake, and improved physical performance, presumably due to the increased NO production.

Treatment of White Phosphorus and Other Chemical Burn Injuries at One Burn Center Over a 51-year Period

DTIC Science & Technology

2004-01-01

cellulose or lauryl sulfate , avoidance of copper- sulfate soaked pads, and use of prompt water or saline rinse following application [19–22,24]. These...0 1 1 Diesel 0 0 1 1 Oven cleaner 0 0 5 5 JP4 fuel 0 0 1 1 Phenol 0 2 2 4 Fluorocarbon 0 2 1 3 Paint thinner 0 1 0 1 Triethylene gycol 0 1 0 1 Sodium ...ammonia 6.8 3.7 Hydrochloric acid 5.6 3.1 Sulfuric acid 4.7 6.5 Polychlorinated biphenyls 2.8 23 Toluene 2.4 1.4 Sodium hydroxide 1.9 2.6 Nitric acid 1.5

Protective effect of Momordica charantia water extract against liver injury in restraint-stressed mice and the underlying mechanism

PubMed Central

Deng, Yuanyuan; Tang, Qin; Zhang, Yan; Zhang, Ruifen; Wei, Zhencheng; Tang, Xiaojun; Zhang, Mingwei

2017-01-01

ABSTRACT Background: Momordica charantia is used in China for its jianghuo (heat-clearing and detoxifying) effects. The concept of shanghuo (the antonym of jianghuo, excessive internal heat) in traditional Chinese medicine is considered a type of stress response of the body. The stress process involves internal organs, especially the liver. Objective: We hypothesized that Momordica charantia water extract (MWE) has a hepatoprotective effect and can protect the body from stress. The aim of this study was to investigate the possible effects of MWE against liver injury in restraint-stressed mice. Design: The mice were intragastrically administered with MWE (250, 500 and 750 mg/kg bw) daily for 7 days. The Normal Control (NC) and Model groups were administered distilled water. A positive control group was intragastrically administered vitamin C 250 mg/kg bw. After the last administration, mice were restrained for 20 h. Results: MWE reduced the serum AST and ALT, reduced the NO content and the protein expression level of iNOSin the liver; significantly reduced the mitochondrial ROS content, increased the mitochondrial membrane potential and the activities of mitochondrial respiratory chain complexes I and II in restraint-stressed mice. Conclusions: The results indicate that MWE has a protective effect against liver injury in restraint-stressed mice. Abbreviations: MWE: Momordica charantia water extract; M. charantia: Momordica charantia L.; ROS: reactive oxygen species; NO: nitric oxide; iNOS: inducible nitric oxide synthase; IL-1β: interleukin-1 beta; TNF-α: tumor necrosis factor alpha; IL-6: interleukin 6; IFN-γ: interferon gamma; VC: vitamin C; ALT: alanine transaminase; AST: aspartate aminotransferase; GSH: glutathione; GSH-PX: glutathione peroxidase; MDA: malondialdehyde; BCA: bicinchoninic acid; TBARS: thiobarbituric acid reactive substances; Trolox: 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid; JC-B: Janus Green B; DW: dry weight; FC: Folin–Ciocalteu; GAE: gallic acid equivalents; bw: body weight; NC: normal control group; Model: restraint stress model group; VC: positive control vitamin C group, 250 mg/kg bw; MWEL: Momordica charantia water extract low-dose group, 250 mg/kg bw; MWEM: Momordica charantia water extract middle-dose group, 500 mg/kg bw; MWEH: Momordica charantia water extract high-dose group, 750 mg/kg bw; HE: hematoxylin and eosin; ORAC: total oxygen radical absorbance capacity; ABAP: dihydrochloride; ATP: adenosine triphosphate PMID:28747868

Protective effect of Momordica charantia water extract against liver injury in restraint-stressed mice and the underlying mechanism.

PubMed

Deng, Yuanyuan; Tang, Qin; Zhang, Yan; Zhang, Ruifen; Wei, Zhencheng; Tang, Xiaojun; Zhang, Mingwei

2017-01-01

Background : Momordica charantia is used in China for its jianghuo (heat-clearing and detoxifying) effects. The concept of shanghuo (the antonym of jianghuo , excessive internal heat) in traditional Chinese medicine is considered a type of stress response of the body. The stress process involves internal organs, especially the liver. Objective : We hypothesized that Momordica charantia water extract (MWE) has a hepatoprotective effect and can protect the body from stress. The aim of this study was to investigate the possible effects of MWE against liver injury in restraint-stressed mice. Design : The mice were intragastrically administered with MWE (250, 500 and 750 mg/kg bw) daily for 7 days. The Normal Control (NC) and Model groups were administered distilled water. A positive control group was intragastrically administered vitamin C 250 mg/kg bw. After the last administration, mice were restrained for 20 h. Results : MWE reduced the serum AST and ALT, reduced the NO content and the protein expression level of iNOSin the liver; significantly reduced the mitochondrial ROS content, increased the mitochondrial membrane potential and the activities of mitochondrial respiratory chain complexes I and II in restraint-stressed mice. Conclusions : The results indicate that MWE has a protective effect against liver injury in restraint-stressed mice. Abbreviations : MWE: Momordica charantia water extract; M. charantia: Momordica charantia L.; ROS: reactive oxygen species; NO: nitric oxide; iNOS: inducible nitric oxide synthase; IL-1β: interleukin-1 beta; TNF-α: tumor necrosis factor alpha; IL-6: interleukin 6; IFN-γ: interferon gamma; VC: vitamin C; ALT: alanine transaminase; AST: aspartate aminotransferase; GSH: glutathione; GSH-PX: glutathione peroxidase; MDA: malondialdehyde; BCA: bicinchoninic acid; TBARS: thiobarbituric acid reactive substances; Trolox: 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid; JC-B: Janus Green B; DW: dry weight; FC: Folin-Ciocalteu; GAE: gallic acid equivalents; bw: body weight; NC: normal control group; Model: restraint stress model group; VC: positive control vitamin C group, 250 mg/kg bw; MWEL: Momordica charantia water extract low-dose group, 250 mg/kg bw; MWEM: Momordica charantia water extract middle-dose group, 500 mg/kg bw; MWEH: Momordica charantia water extract high-dose group, 750 mg/kg bw; HE: hematoxylin and eosin; ORAC: total oxygen radical absorbance capacity; ABAP: dihydrochloride; ATP: adenosine triphosphate.

The Nitric Acid Oxidation of Selected Alcohols and Ketones.

ERIC Educational Resources Information Center

Field, Kurt W.; And Others

1985-01-01

Shows that nitric acid can be used as a rapid, versatile, and economical oxidant for selected organic substances. The experiments (with background information, procedures, and results provided) require one three-hour laboratory period but could serve as open-ended projects since substrates not described could be oxidized. (JN)

Supercritical Fluid Extraction and Separation of Uranium from Other Actinides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donna L. Quach; Bruce J. Mincher; Chien M. Wai

2014-06-01

This paper investigates the feasibility of separating uranium from other actinides by using supercritical fluid carbon dioxide (sc-CO2) as a solvent modified with tri-n-butylphosphate (TBP) for the development of an extraction and counter current stripping technique, which would be a more efficient and environmentally benign technology for used nuclear fuel reprocessing compared to traditional solvent extraction. Several actinides (U(VI), Np(VI), Pu(IV), and Am(III)) were extracted in sc-CO2 modified with TBP over a range of nitric acid concentrations and then the actinides were exposed to reducing and complexing agents to suppress their extractability. According to this study, the separation of uraniummore » from plutonium in sc-CO2 modified with TBP was successful at nitric acid concentrations of less than 3 M in the presence of acetohydroxamic acid or oxalic acid, and the separation of uranium from neptunium was successful at nitric acid concentrations of less than 1 M in the presence of acetohydroxamic acid, oxalic acid, or sodium nitrite.« less

The Reduction of HNO3 to HONO by Volatile Organic Compounds Associated with Rush Hour Traffic

NASA Astrophysics Data System (ADS)

Rutter, A. P.; Malloy, Q.; Scheuer, E.; Gutierrez, C.; Calzada, M.; Dibb, J. E.; Griffin, R. J.

2012-12-01

Nitrous acid (HONO) is an important source of OH radicals in urban environments. However, the sources of HONO are not completely understood, which makes modeling urban atmospheric chemistry difficult. During a previous field study in Houston, TX a correlation was observed between increases in HONO and organic aerosol freshly emitted by motor vehicle traffic during morning rush hours (Ziemba et al., 2010). This source of HONO could not be explained by primary HONO emissions, and the hypothesis was drawn that the HONO was being formed from the reduction of HNO3 by the organic aerosols emitted by motor vehicles. To test this hypothesis, nitric acid (HNO3) was combined in a flow tube with aerosols made from automobile engine oil, which were used as a model for the organic aerosols emitted by rush hour traffic. Reduction of the HNO3 to HONO was observed, although the reaction was found to occur with the volatile organic carbon compounds (VOCs) found in the aerosol vapor, and not the particle surfaces. To explore this further Teflon raschig rings were added to the flow tube to increase surface area but the reaction was not enhanced, confirming the reaction to be homogeneous. The HONO formation observed ranged between 0.1 and 0.5 ppb hr-1 with a mean of 0.3±0.1 ppb hr-1, for typical nitric acid concentrations of 4-5 ppb and estimated concentrations of the reactive components in the engine oil vapor of between 200 and 300 ppt. The observations in this study compared well to the cited field study which observed formation rates between 0.05 and 0.5 ppb hr-1 with an average of 0.3±0.15 ppb hr-1. Water vapor was found to decrease the HONO formation rate by 0.1 ppb hr-1 for every1% of increase in the water mixing ratio. Reference Ziemba L.D., Dibb J.E., Griffin R.J., Anderson C.H., Whitlow S.I., Lefer B.L., Rappenglueck B., and Flynn J. (2010) Heterogeneous conversion of nitric acid to nitrous acid on the surface of primary organic aerosol in an urban atmosphere. Atmospheric Environment, 44, 4081-4089 (33). doi: 10.1016/j.atmosenv.2008.12.024. Available on the Internet at ://WOS:000282866300009.

Argon Shrouded Plasma Spraying of Tantalum over Titanium for Corrosion Protection in Fluorinated Nitric Acid Media

NASA Astrophysics Data System (ADS)

Vetrivendan, E.; Jayaraj, J.; Ningshen, S.; Mallika, C.; Kamachi Mudali, U.

2018-02-01

Argon shrouded plasma spraying (ASPS) was used to deposit a Ta coating on commercially pure Ti (CP-Ti) under inert argon, for dissolver vessel application in the aqueous spent fuels reprocessing plant with high plutonium content. Oxidation during plasma spraying was minimized by shrouding argon system. Porosity and oxide content were controlled by optimizing the spraying parameters, to obtain a uniform and dense Ta coating. The Ta particle temperature and velocity were optimized by judiciously controlling the spray parameters, using a spray diagnostic charge-coupled device camera. The corrosion resistance of the Ta coatings developed by ASPS was investigated by electrochemical studies in 11.5 M HNO3 and 11.5 M HNO3 + 0.05 M NaF. Similarly, the durability of the ASPS Ta coating/substrate was evaluated as per ASTM A262 Practice-C test in boiling nitric acid and fluorinated nitric acid for 240 h. The ASPS Ta coating exhibited higher corrosion resistance than the CP-Ti substrate, as evident from electrochemical studies, and low corrosion rate with excellent coating stability in boiling nitric, and fluorinated nitric acid. The results of the present study revealed that tantalum coating by ASPS is a promising strategy for improving the corrosion resistance in the highly corrosive reprocessing environment.

Asiatic acid alleviates hemodynamic and metabolic alterations via restoring eNOS/iNOS expression, oxidative stress, and inflammation in diet-induced metabolic syndrome rats.

PubMed

Pakdeechote, Poungrat; Bunbupha, Sarawoot; Kukongviriyapan, Upa; Prachaney, Parichat; Khrisanapant, Wilaiwan; Kukongviriyapan, Veerapol

2014-01-16

Asiatic acid is a triterpenoid isolated from Centella asiatica. The present study aimed to investigate whether asiatic acid could lessen the metabolic, cardiovascular complications in rats with metabolic syndrome (MS) induced by a high-carbohydrate, high-fat (HCHF) diet. Male Sprague-Dawley rats were fed with HCHF diet with 15% fructose in drinking water for 12 weeks to induce MS. MS rats were treated with asiatic acid (10 or 20 mg/kg/day) or vehicle for a further three weeks. MS rats had an impairment of oral glucose tolerance, increases in fasting blood glucose, serum insulin, total cholesterol, triglycerides, mean arterial blood pressure, heart rate, and hindlimb vascular resistance; these were related to the augmentation of vascular superoxide anion production, plasma malondialdehyde and tumor necrosis factor-alpha (TNF-α) levels (p<0.05). Plasma nitrate and nitrite (NOx) were markedly high with upregulation of inducible nitric oxide synthase (iNOS) expression, but dowregulation of endothelial nitric oxide synthase (eNOS) expression (p<0.05). Asiatic acid significantly improved insulin sensitivity, lipid profiles, hemodynamic parameters, oxidative stress markers, plasma TNF-α, NOx, and recovered abnormality of eNOS/iNOS expressions in MS rats (p<0.05). In conclusion, asiatic acid improved metabolic, hemodynamic abnormalities in MS rats that could be associated with its antioxidant, anti-inflammatory effects and recovering regulation of eNOS/iNOS expression.

Relation of Mercury to Other Chemical Constituents in Ground Water in the Kirkwood-Cohansey Aquifer System, New Jersey Coastal Plain, and Mechanisms for Mobilization of Mercury from Sediments to Ground Water

USGS Publications Warehouse

Barringer, Julia L.; MacLeod, Cecilia L.

2001-01-01

Water from 265 domestic wells that tap the unconfined Kirkwood-Cohansey aquifer system in the Coastal Plain of New Jersey contained concentrations of mercury that are equal to or exceed the U.S. Environmental Protection Agency maximum contaminant level (MCL) of 2 ug/L (micrograms per liter). The wells range in depth from 50 to 200 feet, and are located in 32 discrete, mostly residential, areas that were developed primarily on former agricultural land during the 1950?s through the 1970?s. Concentrations in two other areas exceeded 1 ug/L. Naturally occurring mercury concentrations in ground water from the Kirkwood-Cohansey aquifer system typically are less than 0.01 ug/L, but concentrations in water from some wells were as much as 42 ug/L. No evidence currently exists that conclusively links known point sources such as landfills, industrial operations, or commercial enterprises to most of the elevated concentrations of mercury in ground water in the residential areas. Possible sources of the mercury include pesticides and atmospheric deposition. Analysis of water from wells in 6 of the 34 areas for other constituents indicates that nitrate concentrations also commonly are elevated above background levels (which typically are undetectable at 0.01 milligrams per liter), and exceed the MCL of 10 milligrams per liter in some samples. Several volatile organic compounds (VOCs), including chloroform, also have been measured in water from wells at many of the 34 sites. Analytical results for water samples collected at several depths from boreholes at 2 of the 34 sites indicate elevated concentrations of calcium, magnesium, barium, strontium, nitrate, and chloride, which may be related to both agricultural chemical applications and septic-system effluent. Determinations of tritium and helium concentrations indicate that water containing elevated concentrations of mercury recharged the aquifer between 9.4 and 79 years ago, which includes the period during which many of the 34 sites were undergoing a change from agricultural or undeveloped to residential land use. Batch equilibrium experiments were used to measure adsorption of dissolved mercury, mercuric chloride, and phenylmercuric acetate by aquifer sediments at pH 3.5-4.0, 4.5-5.0, and 5.5-6.0. In nearly all cases, 55 to 95 percent of the mercury added to the sediments was adsorbed. Mercury mobilization from aquifer sediments inoculated with mercury was investigated by leaching the sediments with two concentrations of nitric acid (a component of acid rain), a sodium chloride solution (simulating road salt), and three fertilizer solutions. A solution of 20-20-20 (nitrogenphosphorous-potassium) fertilizer removed virtually all of the mercury with which the sediments had been inoculated. The sodium chloride solution was moderately effective in removing applied mercury from the sediments, as was a solution of nitric acid. A more dilute nitric acid solution and two sodium nitrate fertilizer solutions were less effective. Results of these experiments indicate that mercury adsorbs to aquifer sediments, but that varying amounts can be removed by infiltrating solutions, some of which can be related to specific land uses. Land-use history at the 34 sites generally indicates a change from agricultural or undeveloped settings to residential settings. Whatever the source of mercury to these sites, a change in the geochemical environment of the soil and aquifer brought about by land-use change probably provides mechanisms for mobilizing the mercury from soils and sediments to ground water.

Nitric acid treated multi-walled carbon nanotubes optimized by Taguchi method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shamsuddin, Shahidah Arina; Hashim, Uda; Halim, Nur Hamidah Abdul

Electron transfer rate (ETR) of CNTs can be enhanced by increasing the amounts of COOH groups to their wall and opened tips. With the aim to achieve the highest production amount of COOH, Taguchi robust design has been used for the first time to optimize the surface modification of MWCNTs by nitric acid oxidation. Three main oxidation parameters which are concentration of acid, treatment temperature and treatment time have been selected as the control factors that will be optimized. The amounts of COOH produced are measured by using FTIR spectroscopy through the absorbance intensity. From the analysis, we found thatmore » acid concentration and treatment time had the most important influence on the production of COOH. Meanwhile, the treatment temperature will only give intermediate effect. The optimum amount of COOH can be achieved with the treatment by 8.0 M concentration of nitric acid at 120 °C for 2 hour.« less

Assessing the Parameterization of Nitric Oxide Emissions By Lightning in a Chemical Transport Model with Nitric Acid Columns from the IASI Satellite Instrument

NASA Astrophysics Data System (ADS)

Cooper, M.; Martin, R.; Wespes, C.; Coheur, P. F.; Clerbaux, C.; Murray, L. T.

2014-12-01

Nitrogen oxides (NOx ≡ NO + NO2) in the free troposphere largely control the production of ozone (O3), an important greenhouse gas and atmospheric oxidant. As HNO3 is the dominant sink of tropospheric NOx, improved understanding of its production and loss mechanisms can help to better constrain NOx emissions, and in turn improve understanding of ozone production and its effect on climate. However, this understanding is inhibited by the scarcity of direct measurements of free tropospheric HNO3, particularly in the tropics. We interpret tropical tropospheric nitric acid columns from the IASI satellite instrument with a global chemical transport model (GEOS-Chem). Overall GEOS-Chem generally agrees with IASI, however we find that the simulation underestimates IASI nitric acid over Southeast Asia by a factor of two. The bias is confirmed by comparing the GEOS-Chem simulation with additional satellite (HIRDLS, ACE-FTS) and aircraft (PEM-Tropics A and PEM-West B) observations of the middle and upper troposphere. We show that this bias can be explained by the parameterization of lightning NOx emissions, primarily from the misrepresentation of concentrated subgrid lightning NOx plumes. We tested a subgrid lightning plume parameterization and found that an additional 0.5 Tg N with an ozone production efficiency of 15 mol/mol would reduce the regional nitric acid bias from 92% to 6% without perturbing the rest of the tropics. Other sensitivity studies such as modified NOx yield per flash, increased altitude of lightning NOx emissions, or changes to convective mass flux or wet deposition of nitric acid required unrealistic changes to reduce the bias. This work demonstrates the importance of a comprehensive lightning parameterization to constraining NOx emissions.

ADSORPTION PROCEDURE IN PREPARING U$sup 23$$sup 3$

DOEpatents

Stoughton, R.W.

1958-10-14

A process is presented for the separation of protoactinium and thorium from an aqueous nitric acid solution containing these metals. It comprises contacting the solution with a cation exchange phenol-formaldehyde resin containing sulfonic acid groups, and eluting the adsorbed thorium from the resin by means of aqueous nitric acid. Thereafter the adsorbed protoactinium is eluted from the resin by means of an aqueous solution of ammonium fluoride.

Ab Initio Calculations of Singlet and Triplet Excited States of Chlorine Nitrate and Nitric Acid

NASA Technical Reports Server (NTRS)

Grana, Ana M.; Lee, Timothy J.; Head-Gordon, Martin; Langhoff, Stephen R. (Technical Monitor)

1994-01-01

Ab initio calculations of vertical excitations to singlet and triplet excited states of chlorine nitrate and nitric acid are reported. The nature of the electronic transitions are examined by decomposing the difference density into the sum of detachment and attachment densities. Counterparts for the three lowest singlet excited states of nitric acid survive relatively unperturbed in chlorine nitrate, while other low-lying singlet states of chlorine nitrate appear to be directly dissociative in the ClO chromophore. These results suggest an assignment of the two main peaks in the experimental chlorine nitrate absorption spectrum. In addition, triplet vertical excitations and the lowest optimized triplet geometries of both molecules are studied.

Liquid-Phase Heat-Release Rates of the Systems Hydrazine-Nitric Acid and Unsymmetrical Dimethylhydrazine-Nitric Acid

NASA Technical Reports Server (NTRS)

Somogyi, Dezso; Feiler, Charles E.

1960-01-01

The initial rates of heat release produced by the reactions of hydrazine and unsymmetrical dimethylhydrazine with nitric acid were determined in a bomb calorimeter under conditions of forced mixing. Fuel-oxidant weight ratio and injection velocity were varied. The rate of heat release apparently depended on the interfacial area between the propellants. Above a narrow range of injection velocities representing a critical amount of interfacial area, the rates reached a maximum and were almost constant with injection velocity. The maximum rate for hydrazine was about 70 percent greater than that for unsymmetrical dimethylhydrazine. The total heat released did not vary with mixture ratio over the range studied.

A comparison of techniques for preparing fish fillet for ICP-AES multielemental analysis and the microwave digestion of whole fish.

PubMed

Moeller, A; Ambrose, R F; Que Hee, S S

2001-01-01

Four catfish fillet homogenate treatments before multielemental metal analysis by simultaneous inductively coupled plasma/atomic emission spectroscopy were compared in triplicate. These treatments were: nitric acid wet-ashing by Parr bomb digestion; nitric acid wet-ashing by microwave digestion; tetramethylammonium hydroxide/nitric acid wet digestion; and dry-ashing. The tetramethylammonium hydroxide/nitric acid method was imprecise (coefficients of variation > 20%). The dry-ashing method was fast and sensitive but had low recoveries of 50% for spiked Pb and Al and was not as precise as the Parr bomb or microwave treatments. The Parr bomb method was the most precise method but was less sensitive than the microwave method which had nearly the same precision. The microwave method was then adapted to homogenates of small whole fish < or = 3 cm in length. The whole fish homogenate required more vigorous digestion conditions, and addition of more acid after the evaporative step because of the presence of less oxidizable and acid-soluble components than fillet. The whole fish homogenate was also more heterogeneous than catfish fillet. A quality assurance protocol to demonstrate homogenate uniformity is essential. The use of a non-specialized microwave oven system allowed precise results for fillet and whole fish homogenates.

REMOVAL OF CHLORIDE FROM AQUEOUS SOLUTIONS

DOEpatents

Hyman, M.L.; Savolainen, J.E.

1960-01-01

A method is given for dissolving reactor fuel elements in which the uranium is associated with a relatively inert chromium-containing alloy such as stainless steel. An aqueous mixture of acids comprising 2 to 2.5 molar hydrochloric acid and 4 to 8 molar nitric acid is employed in dissolving the fuel element. In order io reduce corrosion in subsequent processing of the resulting solution, chloride values are removed from the solution by contacting it with concentrated nitric acid at an elevated temperature.

Physiological responses of lichens to factorial fumigations with nitric acid and ozone

Treesearch

J. Riddell; P.E. Padgett; T. Nash

2012-01-01

This paper addresses the effects of gaseous nitric acid (HNO3) and ozone (O3), two important air pollutants, on six lichen species with different morphological, ecological, and biological characteristics. The treatment chambers were set up in a factorial design consisting of control chambers, chambers fumigated with HNO

77 FR 53144 - Nitric Acid; Exemption From the Requirement of a Tolerance

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-31

... Cosmetic Act (FFDCA), requesting establishment of an exemption from the requirement of a tolerance. This... ingredients. IV. Aggregate Risk Assessment and Determination of Safety Section 408(c)(2)(A)(i) of FFDCA allows... to assess the hazards of and to make a determination on aggregate exposure for nitric acid including...

Method of separation of yttrium-90 from strontium-90

DOEpatents

Bray, Lane A.; Wester, Dennis W.

1996-01-01

A method for purifying Y-90 from a Sr-90/Y-90 "cow" wherein raw Sr-90/Y-90 source containing impurities is obtained from nuclear material reprocessing. Raw Sr-90/Y-90 source is purified to a fresh Sr-90/Y-90 source "cow" by removing impurities by addition of sodium hydroxide and by removing Cs-137 by further addition of sodium carbonate. The "cow" is set aside to allow ingrowth. An HDEHP organic extractant is obtained from a commercial supplier and further purified by saturation with Cu(II), precipitation with acetone, and washing with nitric acid. The "cow" is then dissolved in nitric acid and the purified HDEHP is washed with nitric acid and scrubbed with either nitric or hydrochloric acid. The dissolved "cow" and scrubbed HDEHP are combined in an organic extraction, separating Y-90 from Sr-90, resulting in a Sr-90/Y-90 concentration ratio of not more than 10(E-7), and a metal impurity concentration of not more than 10 ppm per curie of Y-90. The separated Y-90 may then be prepared for delivery.

Method of separation of yttrium-90 from strontium-90

DOEpatents

Bray, L.A.; Wester, D.W.

1996-04-30

A method is described for purifying Y-90 from a Sr-90/Y-90 ``cow`` wherein raw Sr-90/Y-90 source containing impurities is obtained from nuclear material reprocessing. Raw Sr-90/Y-90 source is purified to a fresh Sr-90/Y-90 source ``cow`` by removing impurities by addition of sodium hydroxide and by removing Cs-137 by further addition of sodium carbonate. The ``cow`` is set aside to allow ingrowth. An HDEHP organic extractant is obtained from a commercial supplier and further purified by saturation with Cu(II), precipitation with acetone, and washing with nitric acid. The ``cow`` is then dissolved in nitric acid and the purified HDEHP is washed with nitric acid and scrubbed with either nitric or hydrochloric acid. The dissolved ``cow`` and scrubbed HDEHP are combined in an organic extraction, separating Y-90 from Sr-90, resulting in a Sr-90/Y-90 concentration ratio of not more than 10(E-7), and a metal impurity concentration of not more than 10 ppm per curie of Y-90. The separated Y-90 may then be prepared for delivery. 1 fig.

Influence of Nucleation Mechanisms on the Radiative Properties of Deep Convective Clouds and Subvisible Cirrus in CRYSTAL/FACE

NASA Technical Reports Server (NTRS)

Toon, Owen B.

2005-01-01

During the past few years we have conducted work on several different topics, as reflected by our publications. As one of the Co-Project scientists for The Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment (CRYSTAL FACE) we worked to help design the mission and then conduct it in the field. Another major activity during the past two years has been to pull together various groups to formulate plans for follow on missions to CRYSTAL FACE. We organized a workshop at the University of Colorado during the summer of 2003 to assess the best locations for future missions. Working with a group of about 10 scientists from around the country we prepared a science-planning document (Tropical Composition, Cloud and Climate Coupling Experiment (TC(sup 4)) that outlined the rationale, locations, strategy to accomplish the goals, and possible payloads for a set of three tropical missions. We also prepared background materials for various NRAs being prepared at NASA Headquarters for missions in Costa Rica, Darwin and Guam. In conjunction with the group at NASA Ames we have helped build a new numerical model for deep convection and have applied that model to simulate the CRYSTAL data. Our goal in particular has been to better understand how convection distributes water vapor isotopes. CRYSTAL observations of water isotopes are very different from those suggested by previous workers who assumed the isotopes would obey Rayleigh fractionation. The water isotope study has several implications. First it is a check on the realism of the deep convection model. Second, the isotopes are a measure of the precipitation removal in the atmosphere. Hence they provide a constraint on a parameter that is difficult to otherwise measure. Finally it has been suggested that isotopes may be the key to unraveling the water transport into the stratosphere and upper troposphere. Such transport is critical both for the radiation balance and for stratospheric chemistry. Ours is the first model that is able to treat this transport. Our initial results have just been submitted to Geophys. Res. Lett (Smith et al., 2005). Essentially we are able to explain the vertical profiles of isotopes in the tropical tropopause transition layer. We are also able to account for stratospheric humidity and isotope abundances with this model. We have also been heavily involved in trying to improve our understanding of nitric acid condensation on ice. Gao et al (2004) have shown that water supersaturations above ice occur when the atmosphere is supersaturated with respect to nitric acid trihydrate. As one of the co-authors of that work, we suggested the mechanism that may explain why this is occurring. Essentially, ice does not like to grow near unit supersaturation, but does so because the water molecules can find sites on the ice surface to attach themselves to before they fly off the ice surface. This phenomena was well known in the 1960s when it was a source of debate about whether condensation and evaporation coefficients for ice would be the same. Evaporation does not require any molecular orientation, while condensation does, so it was possible that the coefficients would differ. They don't differ because the water molecules rapidly move across the surface and find places to attach. Nitric acid may be occupying these preferred sites and therefore the water molecules can't find a desirable place to attach. We anticipate that this research will be the subject of laboratory work during the coming few years. Another possibility that has been suggested is that cubic ice is forming in clouds. We have measured the vapor pressure of cubic ice, and plan to publish that result in the next few months. We have also been working on additional aspects of the condensation of nitric acid on ice. With Y. Kondo we studied the condensation of NOy on ice using the SOLVE data. Gamblin et al. have continued this work. The CRYSTAL NOy and HNO, groups have shown th their data can be fit using standard Langmuir isotherms as suggested in some, but not all, laboratory studies. We have found in the SOLVE data set that this is not the case. Moreover some laboratory studies show there are important kinetic effects that may be occurring in the atmosphere limiting the transfer of nitric acid to the ice. The SOLVE data seem consistent with these studies. We are currently re-analyzing the CRYSTAL data to look for these kinetic effects. There are a number of implications of these studies. One of the more interesting is that the nitric acid coating on ice can be used as a cloud clock to determine how long the cloud parcel has been in existence. We have also been involved with several laboratory studies. We have worked to improve the database on ice optical constants, which are critical for remote sensing. We have also studied the ways in which ice nucleates on clays. We suspect now that the standard theories used for depositional ice nucleation are completely incorrect. Further work will be needed to develop a new theory.

Enhancement of p-nitrophenol adsorption capacity through N2-thermal-based treatment of activated carbons

NASA Astrophysics Data System (ADS)

Álvarez-Torrellas, S.; Martin-Martinez, M.; Gomes, H. T.; Ovejero, G.; García, J.

2017-08-01

In this work several activated carbons showing different textural and chemical properties were obtained by chemical and physical activation methods, using a lignocellulosic material (peach stones) as precursor. The activated carbon resulting from the chemical activation, namely as CAC, revealed the best textural properties (SBET = 1521 m2 g-1, pore volume = 0.90 cm3 g-1) and an acidic character. It was found that the activated carbon obtained at 300 °C (under air atmosphere, PAC_air), and those synthesized at 750 °C in presence of N2 flow with bubbling of water/12 M H3PO4 solution (PAC_N2(H2O)/PAC_N2(H3PO4)), respectively, revealed worse textural properties, compared to CAC. Two functionalization treatments, by using sulphuric acid at boiling temperature (PACS) and nitric acid-urea-N2 heating at 800 °C (PAC-NUT), were applied to PAC_air, in order to enhance the adsorption ability of the carbon material. Several techniques were carried out to characterize the physical and chemical properties of the obtained carbon materials. The modification treatments had influence on the carbon surface properties, since the nitric acid-urea-N2 heating treatment led to a carbon material with highly-improved properties (SBET = 679 m2 g-1, pHIEP = 5.3). Accordingly, the original and modified-carbon materials were tested as adsorbents to remove 4-nitrophenol (4-NP), assessing batch and fixed-bed column adsorption tests. PAC-NUT carbon offered the best adsorption behavior (qe = 234 mg g-1), showing a high ability for the removal of 4-NP from water.

Determination of total mercury in biological and geological samples

USGS Publications Warehouse

Crock, James G.

2005-01-01

The analytical chemist is faced with several challenges when determining mercury in biological and geological materials. These challenges include widespread mercury contamination, both in the laboratory and the environment, possible losses of mercury during sample preparation and digestion, the wide range of mercury values commonly observed, ranging from the low nanogram per gram or per liter for background areas to hundreds of milligrams per kilogram in contaminated or ore-bearing areas, great matrix diversity, and sample heterogeneity1. These factors can be naturally occurring or anthropogenic, but must be addressed to provide a precise and accurate analysis. Although there are many instrumental methods available for the successful determination of mercury, no one technique will address all problems or all samples all of the time. The approach for the determination of mercury used at the U.S. Geological Survey, Crustal Imaging and Characterization Team, Denver Laboratories, utilizes a suite of complementary instrumental methods when approaching a study requiring mercury analyses. Typically, a study could require the analysis of waters, leachates or selective digestions of solids, vegetation, and biological materials such as tissue, bone, or shell, soils, rocks, sediments, coals, sludges, and(or) ashes. No one digestion or sample preparation method will be suitable for all of these matrices. The digestions typically employed at our laboratories include: (i) a closed-vessel microwave method using nitric acid and hydrogen peroxide, followed by digestion/dilution with a nitric acid/sodium dichromate solution, (ii) a robotic open test-tube digestion with nitric acid and sodium dichromate, (iii) a sealed Teflon? vessel with nitric acid and sodium dichromate, (iv) a sealed glass bottle with nitric acid and sodium dichromate, or (v) open test tube digestion with nitric and sulfuric acids and vanadium pentoxide. The common factor in all these digestions is that they are very oxidative to ensure the conversion of all mercury forms into Hg (II). Each method of digestion has its advantages and limitations. The method of detection used in our laboratories involves a combination of an in-house, custom, classic continuous-flow cold-vapor atomic absorption spectrometry (CVAAS), a commercially available, automated, flow-injection and a continuous flow cold-vapor atomic fluorescence spectrometry (CV-AFS) systems, and a relatively new, automated and integrated approach where solid or liquid samples are thermally decomposed under an oxygen atmosphere (a nitrogen atmosphere is used for coals) and the released mercury vapor trapped onto a gold gauze and then thermally released into an AAS system. Other less frequently used instrumental methods available for the determination of mercury include inductively coupled plasma ? optical emission spectrometry (ICP-OES), inductively couple plasma ? mass spectrometry (ICP-MS) (both solution nebulization and laser ablation), and instrumental neutron activation analysis (INAA). Results from two case studies involving the determination of mercury in the challenging matrices of biological materials will be presented. These will include fillet, liver and stomach-content samples from grayling for a baseline/background study in Alaska, and samples of meat tissue and shell material from Tanner crabs from Glacier Bay, Alaska. These studies show that the method of digestion is more important than a very sensitive detection limit for mercury.

Investigation of Pu(IV)-acetohydroxamic acid complex by solvent extraction with di(2-ethylhexyl) phosphoric acid

NASA Astrophysics Data System (ADS)

Brown, M. Alex; Paulenova, Alena; Tkac, Peter

2010-03-01

The stability constant of the Pu(IV)-acetohydroxamic acid complex Pu(AHA)3+ at 1 M ionic strength (pH = 0) has been investigated by method of solvent extraction. Di(2-ethylhexyl) phosphoric acid (HDEHP) was used to extract Pu(IV) from perchloric and nitric acid media at various AHA concentrations. Distribution ratios over a range of ligand concentrations were used in conjunction with graphical methods to obtain logβ1 = 14.3 ± 0.03 in perchloric acid. The stability constant determined from solutions in nitric acid was excluded because of the uncertainty in plutonium speciation.

Method for cleaning bomb-reduced uranium derbies

DOEpatents

Banker, John G.; Wigginton, Hubert L.; Beck, David E.; Holcombe, Cressie E.

1981-01-01

The concentration of carbon in uranium metal ingots induction cast from derbies prepared by the bomb-reduction of uranium tetrafluoride in the presence of magnesium is effectively reduced to less than 100 ppm by removing residual magnesium fluoride from the surface of the derbies prior to casting. This magnesium fluoride is removed from the derbies by immersing them in an alkali metal salt bath which reacts with and decomposes the magnesium fluoride. A water quenching operation followed by a warm nitric acid bath and a water rinse removes the residual salt and reaction products from the derbies.

Method for cleaning bomb-reduced uranium derbies

DOEpatents

Banker, J.G.; Wigginton, H.L.; Beck, D.E.; Holcombe, C.E.

The concentration of carbon in uranium metal ingots induction cast from derbies prepared by the bomb-reduction of uranium tetrafluoride in the presence of magnesium is effectively reduced to less than 100 ppM by removing residual magnesium fluoride from the surface of the derbies prior to casting. This magnesium fluoride is removed from the derbies by immersing them in an alkali metal salt bath which reacts with and decomposes the magnesium fluoride. A water quenching operation followed by a warm nitric acid bath and a water rinse removes the residual salt and reaction products from the derbies.

Forensic Discrimination of Concrete Pieces by Elemental Analysis of Acid-soluble Component with Inductively Coupled Plasma-Mass Spectrometry.

PubMed

Kasamatsu, Masaaki; Igawa, Takao; Suzuki, Shinichi; Suzuki, Yasuhiro

2018-01-01

Since fragments of concrete can be evidence of crime, a determination of whether or not they come from the same origin is required. The authors focused on nitric acid-soluble components in the fragments of concrete. As a result of qualitative analysis with ICP-MS, it was confirmed that elements such as Cu, Zn, Rb, Sr, Zr, Ba, La, Ce, Nd, and Pb were contained in the fragments. After the nitric acid-soluble components in the fragments of concrete were separated by dissolving them in nitric acid, the concentrations of these elements in the dissolved solution were quantitatively determined by ICP-MS. The concentration ratios of nine elements compared to La were used as indicators. By comparing these indicators, it was possible to discriminate between the fragments of concrete.

Alternative to Nitric Acid Passivation

NASA Technical Reports Server (NTRS)

Kessel, Kurt R.

2016-01-01

Corrosion is an extensive problem that affects the National Aeronautics and Space Administration (NASA) and European Space Agency (ESA). The deleterious effects of corrosion result in steep costs, asset downtime affecting mission readiness, and safety risks to personnel. It is vital to reduce corrosion costs and risks in a sustainable manner. The primary objective of this effort is to qualify citric acid as an environmentally-preferable alternative to nitric acid for passivation of stainless steel alloys.

Enhanced Performance of Thin Film Composite Forward Osmosis Membrane by Chemical Post-Treatment

NASA Astrophysics Data System (ADS)

Liu, Zheng; Chen, Jiangrong; Cao, Zhen; Wang, Jian; Guo, Chungang

2018-01-01

Forward osmosis is an attractive technique in water purification and desalination fields. Enhancement of the forward osmosis membrane performance is essential to the application of this technique. In this study, an optimized chemical post-treatment approach which was used to improve RO membrane performance was employed for enhancing water flux of thin film composite forward osmosis membrane. Home-made polysulfide-based forward osmosis membrane was prepared and nitric acid, sulfuric acid, ethanol, 2-propanol were employed as post-treatment solutions. After a short-term treatment, all the membrane samples manifested water flux enhancement compared with their untreated counterparts. Over 50% increase of water flux had been obtained by ethanol solution treatment. The swelling, changes of hydrophobicity and solvency in both active layer and substrate were verified as the major causes for the enhancement of the water flux. It is noted that the treatment time and solution concentration should be controlled to get both appropriate water flux and reverse salt flux. The results obtained in this study will be useful for further FO membrane development and application.

Acid Rain

USGS Publications Warehouse

Bricker, Owen P.; Rice, Karen C.

1995-01-01

Although acid rain is fading as a political issue in the United States and funds for research in this area have largely disappeared, the acidity of rain in the Eastern United States has not changed significantly over the last decade, and it continues to be a serious environmental problem. Acid deposition (commonly called acid rain) is a term applied to all forms of atmospheric deposition of acidic substances - rain, snow, fog, acidic dry particulates, aerosols, and acid-forming gases. Water in the atmosphere reacts with certain atmospheric gases to become acidic. For example, water reacts with carbon dioxide in the atmosphere to produce a solution with a pH of about 5.6. Gases that produce acids in the presence of water in the atmosphere include carbon dioxide (which converts to carbonic acid), oxides of sulfur and nitrogen (which convert to sulfuric and nitric acids}, and hydrogen chloride (which converts to hydrochloric acid). These acid-producing gases are released to the atmosphere through natural processes, such as volcanic emissions, lightning, forest fires, and decay of organic matter. Accordingly, precipitation is slightly acidic, with a pH of 5.0 to 5.7 even in undeveloped areas. In industrialized areas, most of the acid-producing gases are released to the atmosphere from burning fossil fuels. Major emitters of acid-producing gases include power plants, industrial operations, and motor vehicles. Acid-producing gases can be transported through the atmosphere for hundreds of miles before being converted to acids and deposited as acid rain. Because acids tend to build up in the atmosphere between storms, the most acidic rain falls at the beginning of a storm, and as the rain continues, the acids "wash out" of the atmosphere.

The influence of activated carbon surface properties on the adsorption of the herbicide molinate and the bio-regeneration of the adsorbent.

PubMed

Coelho, Cláudia; Oliveira, Ana Sofia; Pereira, Manuel Fernando R; Nunes, Olga C

2006-11-16

In the present study, the effect of the textural and surface chemistry properties of the activated carbon were evaluated in a combined treatment system to remove the herbicide molinate from waters. The process consists of an initial adsorption step followed by the bio-regeneration of the activated carbon through the utilization of a defined bacterial mixed culture (DC), previously described as able to mineralize molinate. Molinate adsorption and partial bio-regeneration was favoured with activated carbons with larger pores, consisting mainly of meso and macropores. In order to study the effect of different surface chemical characteristics while maintaining the original textural properties, a commercial activated carbon was submitted to thermal and nitric acid treatments. The thermal treatment improved the molinate adsorption capacity of activated carbon. However, the bio-regeneration of the nitric acid oxidised activated carbon was slightly higher. With all the activated carbon materials used it was observed that the biological consumption of molinate present in the liquid phase displaced the equilibrium towards the activated carbon partial regeneration.

Microbial removal of no.sub.x from gases

DOEpatents

Sublette, Kerry L.

1991-01-01

Disclosed is a process by which a gas containing nitric oxide is contacted with an anaerobic microbial culture of denitrifying bacteria to effect the chemical reduction of the nitric oxide to elemental nitrogen. The process is particularly suited to the removal of nitric oxide from flue gas streams and gas streams from nitric acid plants. Thiobacillus dentrificians as well as other bacteria are disclosed for use in the process.

Ozone, nitric acid, and ammonia air pollution is unhealthy for people and ecosystems in southern Sierra Nevada, California

Treesearch

R. Cisneros; A. Bytnerowicz; D. Schweizer; S. Zhong; S. Traina; D.H. Bennett

2010-01-01

Two-week average concentrations of ozone (O3), nitric acid vapor (HNO3) and ammonia (NH3) were measured with passive samplers during the 2002 summer season across the central Sierra Nevada Mountains, California, along the San Joaquin River drainage. Elevated concentrations of the pollutants were...

40 CFR 98.222 - GHGs to report.

Code of Federal Regulations, 2010 CFR

2010-07-01

... GREENHOUSE GAS REPORTING Nitric Acid Production § 98.222 GHGs to report. (a) You must report N2O process emissions from each nitric acid production train as required by this subpart. (b) You must report under subpart C of this part (General Stationary Fuel Combustion Sources) the emissions of CO2, CH4, and N2O...

40 CFR 98.222 - GHGs to report.

Code of Federal Regulations, 2012 CFR

2012-07-01

... GREENHOUSE GAS REPORTING Nitric Acid Production § 98.222 GHGs to report. (a) You must report N2O process emissions from each nitric acid production train as required by this subpart. (b) You must report under subpart C of this part (General Stationary Fuel Combustion Sources) the emissions of CO2, CH4, and N2O...

40 CFR 98.222 - GHGs to report.

Code of Federal Regulations, 2013 CFR

2013-07-01

... GREENHOUSE GAS REPORTING Nitric Acid Production § 98.222 GHGs to report. (a) You must report N2O process emissions from each nitric acid production train as required by this subpart. (b) You must report under subpart C of this part (General Stationary Fuel Combustion Sources) the emissions of CO2, CH4, and N2O...

40 CFR 98.222 - GHGs to report.

Code of Federal Regulations, 2011 CFR

2011-07-01

... GREENHOUSE GAS REPORTING Nitric Acid Production § 98.222 GHGs to report. (a) You must report N2O process emissions from each nitric acid production train as required by this subpart. (b) You must report under subpart C of this part (General Stationary Fuel Combustion Sources) the emissions of CO2, CH4, and N2O...

Variation in isotopologues of atmospheric nitric acid in passively collected samples along an air pollution gradient in southern California

Treesearch

Michael D. Bell; James O. Sickman; Andrzej Bytnerowicz; Pamela E. Padgett; Edith B. Allen

2014-01-01

The sources and oxidation pathways of atmospheric nitric acid (HNO3) can be evaluated using the isotopic signatures of oxygen (O) and nitrogen (N). This study evaluated the ability of Nylasorb nylon filters to passively collect unbiased isotopologues of atmospheric HNO3 under controlled and field conditions. Filters...

Contrasting physiological responses of ozone-tolerant Phaseolus vulgaris and Nicotiana tobaccum varieties to ozone and nitric acid

Treesearch

Cara M. Stripe; Louis S. Santiago; Pamela E. Padgett

2014-01-01

Ozone (O3) and nitric acid (HNO3) are synthesized by the same atmospheric photochemical processes and are almost always co-pollutants. Effects of O3 on plants have been well-elucidated, yet less is known about the effects of HNO3 on plants. We investigated the physiological...

Spatial and temporal distribution of ambient nitric acid and ammonia in the Athabasca Oil Sands Region, Alberta

Treesearch

A. Bytnerowicz; W. Fraczek; S. Schilling; D. Alexander

2010-01-01

Monthly average ambient concentrations of gaseous nitric acid (HNO3) and ammonia (NH3) were monitored at the Athabasca Oils Sands Region (AOSR), Alberta, Canada, between May 2005 and September 2008. Generally, concentrations of both pollutants were elevated and highly variable in space and time. The highest atmospheric...

URANIUM EXTRACTION

DOEpatents

Harrington, C.D.; Opie, J.V.

1958-07-01

The recovery of uranium values from uranium ore such as pitchblende is described. The ore is first dissolved in nitric acid, and a water soluble nitrate is added as a salting out agent. The resulting feed solution is then contacted with diethyl ether, whereby the bulk of the uranyl nitrate and a portion of the impurities are taken up by the ether. This acid ether extract is then separated from the aqueous raffinate, and contacted with water causing back extractioa of the uranyl nitrate and impurities into the water to form a crude liquor. After separation from the ether extract, this crude liquor is heated to about 118 deg C to obtain molten uranyl nitrate hexahydratc. After being slightly cooled the uranyl nitrate hexahydrate is contacted with acid free diethyl ether whereby the bulk of the uranyl nitrate is dissolved into the ethcr to form a neutral ether solution while most of the impurities remain in the aqueous waste. After separation from the aqueous waste, the resultant ether solution is washed with about l0% of its volume of water to free it of any dissolved impurities and is then contacted with at least one half its volume of water whereby the uranyl nitrate is extracted into the water to form an aqueous product solution.

A facile method to prepare dual-functional membrane for efficient oil removal and in situ reversible mercury ions adsorption from wastewater

NASA Astrophysics Data System (ADS)

Zhang, Qingdong; Liu, Na; Cao, Yingze; Zhang, Weifeng; Wei, Yen; Feng, Lin; Jiang, Lei

2018-03-01

In this work, a novel thiol covered polyamide (nylon 66) microfiltration membrane was fabricated by combining mussel-inspired chemistry and coupling reaction, which owns excellent dual-function that can simultaneously remove oil from water efficiently and adsorb the mercury ions contained in the wastewater reversibly. Such membrane exhibited high oil/water separation efficiency, outstanding mercury adsorption ability, and good stability. Moreover, it can be regenerated in nitric acid solution, and maintain its good adsorption performance. The as-prepared membrane showed great potentials for water purification to reduce the heavy metal ion pollution and complicated industrial oily wastewater and living wastewater.

A laboratory study of the nucleation kinetics of nitric acid hydrates under stratospheric conditions

NASA Astrophysics Data System (ADS)

James, Alexander D.; Murray, Benjamin J.; Plane, John M. C.

2016-04-01

Measurements of the kinetics of crystallisation of ternary H2O-H2SO4-HNO3 mixtures to produce nitric acid hydrate phases, as occurs in the lower stratosphere, have been a long-standing challenge for investigators in the laboratory. Understanding polar stratospheric chlorine chemistry and thereby ozone depletion is increasingly limited by descriptions of nucleation processes. Meteoric smoke particles have been considered in the past as heterogeneous nuclei, however recent studies suggest that these particles will largely dissolve, leaving mainly silica and alumina as solid inclusions. In this study the nucleation kinetics of nitric acid hydrate phases have been measured in microliter droplets at polar stratospheric cloud (PSC) temperatures, using a droplet freezing assay. A clear heterogeneous effect was observed when silica particles were added. A parameterisation based on the number of droplets activated per nuclei surface area (ns) has been developed and compared to global model data. Nucleation experiments on identical droplets have been performed in an X-Ray Diffractometer (XRD) to determine the nature of the phase which formed. β-Nitric Acid Trihydrate (NAT) was observed alongside a mixture of Nitric Acid Dihydrate (NAD) phases. It is not possible to determine whether NAT nucleates directly or is formed by a phase transition from NAD (likely requiring the presence of a mediating liquid phase). Regardless, these results demonstrate the possibility of forming NAT on laboratory timescales. In the polar stratosphere, sulfuric acid (present at several weight percent of the liquid under equilibrium conditions) could provide such a liquid phase. This study therefor provides insight into previous discrepancies between phases formed in the laboratory and those observed in the atmosphere. It also provides a basis for future studies into atmospheric nucleation of solid PSCs.

Reduction of Pertechnetate By Acetohydroxamic Acid: Formation of [tc**II(NO)(AHA)(2)(H(2)O)]**+ And Implications for the UREX Process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gong, C.-M.S.; Lukens, W.W.; Poineau, F.

2009-05-18

Reductive nitrosylation and complexation of ammonium pertechnetate by acetohydroxamic acid has been achieved in aqueous nitric and perchloric acid solutions. The kinetics of the reaction depend on the relative concentrations of the reaction components and are accelerated at higher temperatures. The reaction does not occur unless conditions are acidic. Analysis of the X-ray absorption fine structure spectroscopic data is consistent with a pseudo-octahedral geometry and the linear Tc-N-O bond typical of technetium nitrosyl compounds, and electron spin resonance spectroscopy is consistent with a d{sup 5} Tc(II) nitrosyl complex. The nitrosyl source is generally AHA, but it may be augmented bymore » some products of the reaction with nitric acid. The resulting low-valency trans-aquonitrosyl(diacetohydroxamic)-technetium(II) complex ([Tc{sup II}(NO)(AHA){sub 2}H{sub 2}O]{sup +}, 1) is highly soluble in water, extremely hydrophilic, and is not extracted by tri-n-butylphosphate in a dodecane diluent. Its extraction properties are not pH-dependent: potentiometric-spectrophotometric titration studies indicate a single species from pH 4 down to -0.6 (calculated). This molecule is resistant to oxidation by H{sub 2}O{sub 2}, even at high pH, and can undergo substitution to form other technetium nitrosyl complexes. The potential formation of 1 during reprocessing may strongly impact the fate of technetium in the nuclear fuel cycle.« less

Biofuel cell anode: NAD +/glucose dehydrogenase-coimmobilized ketjenblack electrode

NASA Astrophysics Data System (ADS)

Miyake, T.; Oike, M.; Yoshino, S.; Yatagawa, Y.; Haneda, K.; Kaji, H.; Nishizawa, M.

2009-09-01

We have studied the coimmobilization of glucose dehydrogenase (GDH) and its cofactor, oxidized nicotinamide adenine dinucleotide (NAD +), on a ketjenblack (KB) electrode as a step toward a biofuel cell anode that works without mediators. A KB electrode was first treated with a sulfuric acid/nitric acid/water mixture to lower the overvoltage for NADH oxidation, and was next chemically modified with NAD + and GDH. The improved GDH/NAD +/KB electrode is found to oxidize glucose around 0 V vs. Ag/AgCl. A biofuel cell constructed with a bilirubin oxidase-immobilized KB cathode showed a maximum power density of 52 μW/cm 2 at 0.3 V.

Release of volatile mercury from vascular plants

NASA Technical Reports Server (NTRS)

Siegel, S. M.; Puerner, N. J.; Speitel, T. W.

1974-01-01

Volatile, organic solvent soluble mercury has been found in leaves and seeds of several angiosperms. Leaves of garlic vine, avocado, and haole-koa release mercury in volatile form rapidly at room temperature. In garlic vine, the most active release is temperature dependent, but does not parallel the vapor-pressure temperature relationship for mercury. Mercury can be trapped in nitric-perchloric acid digestion fluid, or n-hexane, but is lost from the hexane unless the acid mixture is present. Seeds of haole-koa also contain extractable mercury but volatility declines in the series n-hexane (90%), methanol (50%), water (10%). This suggests that reduced volatility may accompany solvolysis in the more polar media.

URANIUM DECONTAMINATION

DOEpatents

Buckingham, J.S.; Carroll, J.L.

1959-12-22

A process is described for reducing the extractability of ruthenium, zirconium, and niobium values into hexone contained in an aqueous nitric acid uranium-containing solution. The solution is made acid-deficient, heated to between 55 and 70 deg C, and at that temperature a water-soluble inorganic thiosulfate is added. By this, a precipitate is formed which carries the bulk of the ruthenium, and the remainder of the ruthenium as well as the zirconium and niobium are converted to a hexone-nonextractable form. The rutheniumcontaining precipitate can either be removed from the solu tion or it can be dissolved as a hexone-non-extractable compound by the addition of sodium dichromate prior to hexone extraction.

IMPROVED PROCESS OF PLUTONIUM CARRIER PRECIPITATION

DOEpatents

Faris, B.F.

1959-06-30

This patent relates to an improvement in the bismuth phosphate process for separating and recovering plutonium from neutron irradiated uranium, resulting in improved decontamination even without the use of scavenging precipitates in the by-product precipitation step and subsequently more complete recovery of the plutonium in the product precipitation step. This improvement is achieved by addition of fluomolybdic acid, or a water soluble fluomolybdate, such as the ammonium, sodium, or potassium salt thereof, to the aqueous nitric acid solution containing tetravalent plutonium ions and contaminating fission products, so as to establish a fluomolybdate ion concentration of about 0.05 M. The solution is then treated to form the bismuth phosphate plutonium carrying precipitate.

Final Report of Tank 241-C-105 Dissolution, the Phase 2 Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meznarich, Huei K.; bolling, Stacey D.; Cooke, Gary A.

2016-10-01

Three clamshell grab samples were taken from Tank 241-C-105 in October 2015 in accordance with RPP-PLAN-60011. Analytical results of those samples were issued in the report RPP-RPT-59115 by Wastren Advantage, Inc., Hanford Laboratory. Solid phase characterization results were reported separately in LAB-RPT-15-00011 and in RPP-RPT-59147. The major solid phases reported to be present were dawsonite [NaAlCO 3(OH) 2], trona [Na 3(HCO 3)(CO 3)·2H 2O], cejkaite [Na 4(UO 2)(CO 3) 3], and an unidentified organic solid, with minor amounts of gibbsite [Al(OH) 3], natrophosphate [Na 7F(PO 4) 2·19H 2O], and traces of unidentified iron-rich and manganese-rich phases. Note that the presencemore » of dawsonite, trona, and cejkaite requires a relatively low pH, likely around pH 9 to 10. One aliquot of each grab sample was provided to 222-S Laboratory Process Chemistry for dissolution studies. Phase 1 of the dissolution testing followed the approved test plan, WRPS-1404813, Rev. 3, and examined the behavior of the Tank 241-C-105 solids treated with water, 19M sodium hydroxide, 2M nitric acid, and 0.5M oxalic acid/2M nitric acid. Phase 2 of the testing was conducted in accordance with instructions from the client and emphasized treatment with 19M sodium hydroxide followed by water washing. This is the report of the Phase 2 testing.« less

Overview of reductants utilized in nuclear fuel reprocessing/recycling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patricia Paviet-Hartmann; Catherine Riddle; Keri Campbell

2013-10-01

Most of the aqueous processes developed, or under consideration worldwide for the recycling of used nuclear fuel (UNF) utilize the oxido-reduction properties of actinides to separate them from other radionuclides. Generally, after acid dissolution of the UNF, (essentially in nitric acid solution), actinides are separated from the raffinate by liquid-liquid extraction using specific solvents, associated along the process, with a particular reductant that will allow the separation to occur. For example, the industrial PUREX process utilizes hydroxylamine as a plutonium reductant. Hydroxylamine has numerous advantages: not only does it have the proper attributes to reduce Pu(IV) to Pu(III), but itmore » is also a non-metallic chemical that is readily decomposed to innocuous products by heating. However, it has been observed that the presence of high nitric acid concentrations or impurities (such as metal ions) in hydroxylamine solutions increase the likelihood of the initiation of an autocatalytic reaction. Recently there has been some interest in the application of simple hydrophilic hydroxamic ligands such as acetohydroxamic acid (AHA) for the stripping of tetravalent actinides in the UREX process flowsheet. This approach is based on the high coordinating ability of hydroxamic acids with tetravalent actinides (Np and Pu) compared with hexavalent uranium. Thus, the use of AHA offers a route for controlling neptunium and plutonium in the UREX process by complexant based stripping of Np(IV) and Pu(IV) from the TBP solvent phase, while U(VI) ions are not affected by AHA and remain solvated in the TBP phase. In the European GANEX process, AHA is also used to form hydrophilic complexes with actinides and strip them from the organic phase into nitric acid. However, AHA does not decompose completely when treated with nitric acid and hampers nitric acid recycling. In lieu of using AHA in the UREX + process, formohydroxamic acid (FHA), although not commercially available, hold promises as a replacement for AHA. FHA undergoes hydrolysis to formic acid which is volatile, thus allowing the recycling of nitric acid. Unfortunately, FHA powder was not stable in the experiments we ran in our laboratory. In addition, AHA and FHA also decompose to hydroxylamine which may undergo an autocatalytic reaction. Other reductants are available and could be extremely useful for actinides separation. The review presents the current plutonium reductants used in used nuclear fuel reprocessing and will introduce innovative and novel reductants that could become reducers for future research on UNF separation.« less

Methylhydrazinium nitrate. [rocket plume deposit chemistry

NASA Technical Reports Server (NTRS)

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

1983-01-01

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.

Cost-Effective Red Water Disposal by Electron Beam Radiolysis.

DTIC Science & Technology

1994-06-28

mixed with amonium nitrate to form Amatols, or with aluminum powder to form Tritonal, or with RDX to form Cyclonite, or with Composition B. It is also...Department of’ the Army position, policy, or decision, unless so designated by other documentation. ILPM~ fi 4 vbm. d ) MASTER COPY KEEP THIS COPY FOR...by nitration of toluene, meta-nitrotoluene or ortho-nitrotoluene U with mixed nitric and sulfuric acid in several steps. Insoluble and unwanted

A new sol-gel synthesis of 45S5 bioactive glass using an organic acid as catalyst.

PubMed

Faure, J; Drevet, R; Lemelle, A; Ben Jaber, N; Tara, A; El Btaouri, H; Benhayoune, H

2015-02-01

In this paper a new sol-gel approach was explored for the synthesis of the 45S5 bioactive glass. We demonstrate that citric acid can be used instead of the usual nitric acid to catalyze the sol-gel reactions. The substitution of nitric acid by citric acid allows to reduce strongly the concentration of the acid solution necessary to catalyze the hydrolysis of silicon and phosphorus alkoxides. Two sol-gel powders with chemical compositions very close to that of the 45S5 were obtained by using either a 2M nitric acid solution or either a 5mM citric acid solution. These powders were characterized and compared to the commercial Bioglass®. The surface properties of the two bioglass powders were assessed by scanning electron microscopy (SEM) and by Brunauer-Emmett-Teller method (BET). The Fourier transformed infrared spectroscopy (FTIR) and the X-ray diffraction (XRD) revealed a partial crystallization associated to the formation of crystalline phases on the two sol-gel powders. The in vitro bioactivity was then studied at the key times during the first hours of immersion into acellular Simulated Body Fluid (SBF). After 4h immersion into SBF we clearly demonstrate that the bioactivity level of the two sol-gel powders is similar and much higher than that of the commercial Bioglass®. This bioactivity improvement is associated to the increase of the porosity and the specific surface area of the powders synthesized by the sol-gel process. Moreover, the nitric acid is efficiently substituted by the citric acid to catalyze the sol-gel reactions without alteration of the bioactivity of the 45S5 bioactive glass. Copyright © 2014 Elsevier B.V. All rights reserved.

Chemical kinetic studies of atmospheric reactions using tunable diode laser spectroscopy

NASA Technical Reports Server (NTRS)

Worsnop, Douglas R.; Nelson, David D.; Zahniser, Mark S.

1993-01-01

IR absorption using tunable diode laser spectroscopy provides a sensitive and quantitative detection method for laboratory kinetic studies of atmospheric trace gases. Improvements in multipass cell design, real time signal processing, and computer controlled data acquisition and analysis have extended the applicability of the technique. We have developed several optical systems using off-axis resonator mirror designs which maximize path length while minimizing both the sample volume and the interference fringes inherent in conventional 'White' cells. Computerized signal processing using rapid scan (300 kHz), sweep integration with 100 percent duty cycle allows substantial noise reduction while retaining the advantages of using direct absorption for absolute absorbance measurements and simultaneous detection of multiple species. Peak heights and areas are determined by curve fitting using nonlinear least square methods. We have applied these techniques to measurements of: (1) heterogeneous uptake chemistry of atmospheric trace gases (HCl, H2O2, and N2O5) on aqueous and sulfuric acid droplets; (2) vapor pressure measurements of nitric acid and water over prototypical stratospheric aerosol (nitric acid trihydrate) surfaces; and (3) discharge flow tube kinetic studies of the HO2 radical using isotopic labeling for product channel and mechanistic analysis. Results from each of these areas demonstrate the versatility of TDL absorption spectroscopy for atmospheric chemistry applications.

Ionic Liquid Fuels for Chemical Propulsion

DTIC Science & Technology

2014-11-20

researchers seeking hypergolic fuels have limited themselves to the extremely toxic and corrosive nitric acid solutions. While important questions remain...storable oxidizer (N204 , nitric acid ) have been synthesized and demonstrated. The bipropellant fuels are based upon salts containing dicyanamide or...20-30% nanoparticle loading but decreases between 10-20%, perhaps indicating an optimal loading concentration for these nanoparticles between 10-20

RECOVERY OF ACTINIDES FROM AQUEOUS NITRIC ACID SOLUTIONS

DOEpatents

Ader, M.

1963-11-19

A process of recovering actinides is presented. Tetravalent actinides are extracted from rare earths in an aqueous nitric acid solution with a ketone and back-extracted from the ketone into an aqueous medium. The aqueous actinide solution thus obtained, prior to concentration by boiling, is sparged with steam to reduce its ketone to a maximum content of 3 grams per liter. (AEC)

40 CFR 60.74 - Test methods and procedures.

Code of Federal Regulations, 2014 CFR

2014-07-01

... production rate, metric ton/hr (ton/hr) or 100 percent nitric acid. K=conversion factor, 1000 g/kg (1.0 lb/lb...=emission rate of NOX as NO2, kg/metric ton (lb/ton) of 100 percent nitric acid. Cs = concentration of NOX... over the production system shall be used to confirm the production rate. (c) The owner or operator may...

40 CFR 60.74 - Test methods and procedures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... rate, metric ton/hr (ton/hr) or 100 percent nitric acid. K=conversion factor, 1000 g/kg (1.0 lb/lb). (2...=emission rate of NOX as NO2, kg/metric ton (lb/ton) of 100 percent nitric acid. Cs=concentration of NOX as... system shall be used to confirm the production rate. (c) The owner or operator may use the following as...

40 CFR 60.74 - Test methods and procedures.

Code of Federal Regulations, 2013 CFR

2013-07-01

... rate, metric ton/hr (ton/hr) or 100 percent nitric acid. K=conversion factor, 1000 g/kg (1.0 lb/lb). (2...=emission rate of NOX as NO2, kg/metric ton (lb/ton) of 100 percent nitric acid. Cs=concentration of NOX as... system shall be used to confirm the production rate. (c) The owner or operator may use the following as...

40 CFR 60.74 - Test methods and procedures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... rate, metric ton/hr (ton/hr) or 100 percent nitric acid. K=conversion factor, 1000 g/kg (1.0 lb/lb). (2...=emission rate of NOX as NO2, kg/metric ton (lb/ton) of 100 percent nitric acid. Cs=concentration of NOX as... system shall be used to confirm the production rate. (c) The owner or operator may use the following as...

Foliar loading and metabolic assimilation of dry deposited nitric acid air pollutants by trees

Treesearch

Pamela E. Padgett; Hillary Cook; Andrzej Bytnerowicz; Robert L. Heath

2009-01-01

Dry deposition of nitric acid vapor (HNO(3)) is a major contributor to eutrophication of natural ecosystems. Although soil fertilization by nitrogen deposition is considered to be the primary pathway for changes in plant nutrient status and shifts in ecological structure, the aerial portion of plants offer many times the surface area in which to...

Spectroscopic studies of model polar stratospheric cloud films

NASA Technical Reports Server (NTRS)

Tolbert, Margaret A.; Koehler, Birgit G.; Middlebrook, Ann M.

1993-01-01

Fourier transform infrared (FTIR) spectroscopy has been used to study nitric-acid/ice films representative of type I polar stratospheric clouds (PSCs). These studies reveal that in addition to amorphous nitric acid/ice mixtures, there are three stable stoichiometric hydrates of nitric acid: nitric-acid monohydrate (NAM), dihydrate (NAD), and trihydrate (NAT). We also observe two distinct crystalline forms of the trihydrate, which we denote alpha- and beta-NAT. These two forms appear to differ in their concentration of crystalline defects, but not in their chemical composition. In addition to probing the composition of type I PSCs, we have also used FTIR spectroscopy to study the interaction of HCl with model PSC films. In this work we find that for HCl pressures in the range 10 exp -5 to 10 exp -7 Torr, HCl is taken up by ice at 155 K to form a thin layer of HCl.6H2O. At 193 K, the uptake of HCl by ice was consistent with less than or equal to monolayer coverage. Uptake of HCl by alpha and beta-NAT at 175 K was also consistent with less than or equal to monolayer coverage.

VOLTAGE CLAMP BEHAVIOR OF IRON-NITRIC ACID SYSTEM AS COMPARED WITH THAT OF NERVE MEMBRANE

PubMed Central

Tasaki, I.; Bak, A. F.

1959-01-01

The current-voltage relation for the surface layer of an iron wire immersed in nitric acid was investigated by the voltage clamp technique. Comparing the phase of nitric acid to the axoplasm and the metallic phase to the external fluid medium for the nerve fiber, a striking analogy was found between the voltage clamp behavior of the iron-nitric acid system and that of the nerve membrane. The current voltage curve was found to consist of three parts: (a) a straight line representing the behavior of the resting (passive) membrane, (b) a straight line representing the fully excited (active) state, and (c) an intermediate zone connecting (a) and (b). It was shown that in the intermediate zone, the surface of iron consisted of a fully active patch (or patches) surrounded by a remaining resting area. The phenomenon corresponding to "repetitive firing of responses under voltage clamp" in the nerve membrane was demonstrated in the intermediate zone. The behavior of the cobalt electrode system was also investigated by the same technique. An attempt was made to interpret the phenomenon of initiation and abolition of an active potential on the basis of the thermodynamics of irreversible processes. PMID:13654740

Preparation of polyethylene sacks for collection of precipitation samples for chemical analysis

USGS Publications Warehouse

Schroder, L.J.; Bricker, A.W.

1985-01-01

Polyethylene sacks are used to collect precipitation samples. Washing polyethylene with acetone, hexane, methanol, or nitric acid can change the adsorptive characteristics of the polyethylene. In this study, simulated precipitation at pH 4.5 was in contact with the polyethylene sacks for 21 days; subsamples were removed for chemical analysis at 7, 14, and 21 days after intitial contact. Sacks washed with acetone adsorbed iron and lithium; sacks washed with hexane adsorbed barium, iron , and lithium; sacks washed with methanol adsorbed calcium and iron; and sacks washed with 0.30 N nitric acid adsorbed iron. Leaching the plastic sacks with 0.15 N nitric acid did not result in 100-percent recovery of any of the adsorbed metals. Washing polyethylene sacks with dilute nitric acid caused the pH of the simulated precipitation to be decreased by 0.2 pH unit after 1 week of contact with the polyethylene. The specific conductance increased by 10 microsiemens per centimeter. Contamination of precipitation samples by lead was determined to be about 0.1 microgram per liter from contact with precleaned polyethylene sacks. No measurable contamination of precipitation samples by zinc occurred. (USGS)

Nitrous-acid-mediated synthesis of iron-nitrosyl-porphyrin: pH-dependent release of nitric oxide.

PubMed

Bhuyan, Jagannath; Sarkar, Sabyasachi

2012-11-01

Two iron-nitrosyl-porphyrins, nitrosyl[meso-tetrakis(3,4,5-trimethoxyphenylporphyrin]iron(II) acetic acid solvate (3) and nitrosyl[meso-tetrakis(4-methoxyphenylporphyrin]iron(II) CH(2)Cl(2) solvate (4), were synthesized in quantitative yield by using a modified procedure with nitrous acid, followed by oxygen-atom abstraction by triphenylphosphine under an argon atmosphere. These nitrosyl porphyrins are in the {FeNO}(7) class. Under an argon atmosphere, these compounds are relatively stable over a broad range of pH values (4-8) but, under aerobic conditions, they release nitric oxide faster at high pH values than that at low pH values. The generated nitric-oxide-free iron(III)-porphyrin can be re-nitrosylated by using nitrous acid and triphenylphosphine. The rapid release of NO from these Fe(II) complexes at high pH values seems to be similar to that in nitrophorin, a nitric-oxide-transport protein, which formally possesses Fe(III). However, because the release of NO occurs from ferrous-nitrosyl-porphyrin under aerobic conditions, these compounds are more closely related to nitrobindin, a recently discovered heme protein. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Laser Window Materials and Optical Coating Science

DTIC Science & Technology

1977-08-01

nitric, sulphuric, and acetic acids , but attack was too slow or insufficient. Finally, a mixture of nitric and hydrochloric acids was found to...trace of acetic acid . The As2S3 was subsequently mmm ’■ ’■ I .’■ " "■’ ’ reacted with CS-, tor two hours to remove the impurities and...immersing the deforming boule under Cereclor 42P, a chlorinated paraffin. This viscous, honey-colored liquid is 41%, chlorine by weight, and loses

Large-scale production of anhydrous nitric acid and nitric acid solutions of dinitrogen pentoxide

DOEpatents

Harrar, Jackson E.; Quong, Roland; Rigdon, Lester P.; McGuire, Raymond R.

2001-01-01

A method and apparatus are disclosed for a large scale, electrochemical production of anhydrous nitric acid and N.sub.2 O.sub.5. The method includes oxidizing a solution of N.sub.2 O.sub.4 /aqueous-HNO.sub.3 at the anode, while reducing aqueous HNO.sub.3 at the cathode, in a flow electrolyzer constructed of special materials. N.sub.2 O.sub.4 is produced at the cathode and may be separated and recycled as a feedstock for use in the anolyte. The process is controlled by regulating the electrolysis current until the desired products are obtained. The chemical compositions of the anolyte and catholyte are monitored by measurement of the solution density and the concentrations of N.sub.2 O.sub.4.

Synthesis and thermal characterization of xylan-graft-polyacrylonitrile.

PubMed

Ünlü, Cüneyt H; Öztekin, N Simge; Atıcı, Oya Galioğlu

2012-10-01

In this study emulsion polymerization of acrylonitrile using xylan from agricultural waste material (corn cob) and cerium ammonium nitrate was investigated in terms of catalyst acid. Stock ceric solutions were prepared using either nitric or perchloric acid as catalyst. Optimum conditions were determined using different parameters such as reaction time, temperature, and component concentrations. Nitric acid catalyzed reactions resulted in maximum conversion ratio (96%) at 50°C, 1 h where ceric ion, acrylonitrile, xylan, and catalyst concentrations were 21.7 mmol l(-1), 0.5 mol l(-1), 0.2% (w/v), and 0.1 mol l(-1), respectively. However, 83% conversion was obtained with perchloric acid catalysis at 27 °C, 1 h where concentrations were 5.4 mmol l(-1), 0.8 mol l(-1), 0.5% (w/v), and 0.2 mol l(-1), respectively. Copolymer synthesis using perchloric acid was realized at milder conditions than using nitric acid. Thermal analyses of obtained polymers were conducted to characterize copolymers. Results showed that calculated activation energy, maximum degradation temperature, and heat of thermal decomposition changed relying mainly on molecular weight. Copyright © 2012 Elsevier Ltd. All rights reserved.

Process for treating alkaline wastes for vitrification

DOEpatents

Hsu, Chia-lin W.

1995-01-01

A process for treating alkaline wastes for vitrification. The process involves acidifying the wastes with an oxidizing agent such as nitric acid, then adding formic acid as a reducing agent, and then mixing with glass formers to produce a melter feed. The nitric acid contributes nitrates that act as an oxidant to balance the redox of the melter feed, prevent reduction of certain species to produce conducting metals, and lower the pH of the wastes to a suitable level for melter operation. The formic acid reduces mercury compounds to elemental mercury for removal by steam stripping, and MnO.sub.2 to the Mn(II) ion to prevent foaming of the glass melt. The optimum amounts of nitric acid and formic acid are determined in relation to the composition of the wastes, including the concentrations of mercury (II) and MnO.sub.2, noble metal compounds, nitrates, formates and so forth. The process minimizes the amount of hydrogen generated during treatment, while producing a redox-balanced feed for effective melter operation and a quality glass product.

Process for treating alkaline wastes for vitrification

DOEpatents

Hsu, C.L.W.

1995-07-25

A process is described for treating alkaline wastes for vitrification. The process involves acidifying the wastes with an oxidizing agent such as nitric acid, then adding formic acid as a reducing agent, and then mixing with glass formers to produce a melter feed. The nitric acid contributes nitrates that act as an oxidant to balance the redox of the melter feed, prevent reduction of certain species to produce conducting metals, and lower the pH of the wastes to a suitable level for melter operation. The formic acid reduces mercury compounds to elemental mercury for removal by steam stripping, and MnO{sub 2} to the Mn(II) ion to prevent foaming of the glass melt. The optimum amounts of nitric acid and formic acid are determined in relation to the composition of the wastes, including the concentrations of mercury (II) and MnO{sub 2}, noble metal compounds, nitrates, formates and so forth. The process minimizes the amount of hydrogen generated during treatment, while producing a redox-balanced feed for effective melter operation and a quality glass product. 4 figs.

[Participation of nitric oxide and arachidonic acid metabolites via cytochrome - P450 in the regulation of arterial blood pressure].

PubMed

Sánchez-Mendoza, M Alicia; Martínez-Ayala, Sonia O; Hernández-Hernández, José A; Zúñiga-Sosa, Leonor; Pastelín-Hernández, Gustavo; Escalante-Acosta, Bruno A

2003-01-01

Nitric oxide and cytochrome P450 arachidonic acid metabolites participate in blood pressure regulation. The synthesis of these autacoids leads to arterial hypertension. However, it is not known whether there is an interaction between them. Therefore, we studied the modulatory effect of nitric oxide and cytochrome P450-arachidonic acid metabolites, their interaction on blood pressure, and the renal content of cytochrome P450. Male Wistar rats were divided: 1) control, 2) L-NAME (100 mg/kg/d p.o.), 3) L-NAME + SnCl2 (10 mg/kg/d i.p.), and 4) L-NAME + dexamethasone (1 mg/kg/d s.c.). We measured blood pressure and collected urine and blood for nitric oxide measurement. NO2 was quantified by HPLC. Blood pressure was: control, 97 +/- 7 mmHg; L-NAME, 151 +/- 4.6 mmHg; L-NAME + SnCl2, 133 +/- 3 mmHg, and L-NAME + dexamethasone 152 +/- 4.5 mmHg. Urine nitrite concentration was: 1) 1.832 +/- 0.32, 2) 1.031 +/- 0.23, 3) 1.616 +/- 0.33, and 4) 1.244 +/- 0.33 mumol/mL, while the concentration in blood was: 1) 0.293 +/- 0.06, 2) 0.150 +/- 0.05, 3) 0.373 +/- 0.13, and 4) 0.373 +/- 0.07 mumol/mL. L-NAME + SnCl2 decreased cytochrome P450 renal content, and L-NAME + dexamethasone showed a similar response. In conclusion, both, nitric oxide and CYP-arachidonic acid metabolites play a role in the regulation of blood pressure. Nitric oxide also partially regulates renal cytochrome P450 content.

An improved method for emergent decontamination of ocular and dermal hydrofluoric acid splashes.

PubMed

Soderberg, Kjell; Kuusinen, Petri; Mathieu, Laurence; Hall, Alan H

2004-08-01

Accidental hydrofluoric acid (HF) splashes often occur in industrial settings. HF easily penetrates into tissues by initial acid action allowing fluoride ions to penetrate deeply, chelating calcium and magnesium. Resultant hypocalcemia and hypomagnesemia can be fatal. This report describes the utilization of Hexafluorine--a hypertonic, amphoteric, chelating decontamination solution--in workplaces where water decontamination followed by calcium gluconate inunction failed to prevent HF burns and systemic toxicity. Between 1998 and 1999, 16 cases of ocular and dermal HF splashes with either 70% HF or 6% HF/15% nitric acid (HNO3) were decontaminated with Hexafluorine at the worksite. HF burns did not develop and medical treatment other than initial decontamination was not reQuired in 12/16 (75%). In 7/16 (44%) cases, lost work time corresponded to duration of hospital observation (mean < 1 d).

The allelopathic effects of invasive plant Solidago canadensis on seed germination and growth of Lactuca sativa enhanced by different types of acid deposition.

PubMed

Wang, Congyan; Xiao, Hongguang; Zhao, Lulu; Liu, Jun; Wang, Lei; Zhang, Fei; Shi, Yanchun; Du, Daolin

2016-04-01

Invasive species can exhibit allelopathic effects on native species. Meanwhile, the types of acid deposition are gradually changing. Thus, the allelopathic effects of invasive species on seed germination and growth of native species may be altered or even enhanced under conditions with diversified acid deposition. This study aims to assess the allelopathic effects (using leaves extracts) of invasive plant Solidago canadensis on seed germination and growth of native species Lactuca sativa treated with five types of acid deposition with different SO4(2-) to NO3(-) ratios (1:0, sulfuric acid; 5:1, sulfuric-rich acid; 1:1, mixed acid; 1:5, nitric-rich acid; 0:1, nitric acid). Solidago canadensis leaf extracts exhibited significantly allelopathic effects on germination index, vigor index, and germination rate index of L. sativa. High concentration of S. canadensis leaf extracts also similarly exhibited significantly allelopathic effects on root length of L. sativa. This may be due to that S. canadensis could release allelochemicals and then trigger allelopathic effects on seed germination and growth of L. sativa. Acid deposition exhibited significantly negative effects on seedling biomass, root length, seedling height, germination index, vigor index, and germination rate index of L. sativa. This may be ascribed to the decreased soil pH values mediated by acid deposition which could produce toxic effects on seedling growth. Sulfuric acid deposition triggered more toxic effects on seedling biomass and vigor index of L. sativa than nitric acid deposition. This may be attributing to the difference in exchange capacity with hydroxyl groups (OH(-)) between SO4(2-) and NO3(-) as well as the fertilizing effects mediated by nitric deposition. All types of acid deposition significantly enhanced the allelopathic effects of S. canadensis on root length, germination index, vigor index, and germination rate index of L. sativa. This may be due to the negatively synergistic effects of acid deposition and S. canadensis on seed germination and growth of L. sativa. The ratio of SO4(2-) to NO3(-) in acid deposition was an important factor that profoundly affected the allelopathic effects of S. canadensis on the seed germination and growth of L. sativa possibly because the difference in exchange capacity with hydroxyl groups (OH(-)) between SO4(2-) and NO3(-) as well as the fertilizing effects triggered by nitric deposition. Thus, the allelopathic effects of invasive species on seed germination and growth of native plants might be enhanced under increased and diversified acid deposition.

Anti-inflammatory effects of phenolic crude extracts from five fractions of Corchorus Olitorius L.

PubMed

Yan, Yeong-Yu; Wang, Yue-Wen; Chen, Su-Lin; Zhuang, Shu-Ru; Wang, Chin-Kun

2013-06-01

Corchorus olitorius L. is grown in Taiwan during summer. Tender leaves are crushed and washed by running water before eating. Five fractions including crude phenolic extracts (using 80 per cent aqueous acetone) of whole plant, leaf, stem, washed leaf (WL) and dried water washing material (WW) were used in this study. Linoleic acid autoxidation inhibitions on all fractions were higher than that on α-tocopherol. Except for WL and WW, other fractions also showed DPPH radical scavenging efficiency. The effect of all fractions on the regulation of inflammatory responses in lipopolysaccharide (LPS)-stimulated J774A.1 macrophage cells was investigated. All fractions diminished LPS-induced protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2). Nitric oxide (NO) and prostaglandin E2 (PGE(2)), downstream products, were also suppressed in dose-dependent manners, except for WL and WW. Oxidative modification and loss of leaf phenolics after kneading and washing greatly affected DPPH radical scavenging and inflammatory responses. Copyright © 2012 Elsevier Ltd. All rights reserved.

A screening method for cardiovascular active compounds in marine algae.

PubMed

Agatonovic-Kustrin, S; Kustrin, E; Angove, M J; Morton, D W

2018-05-18

The interaction of bioactive compounds from ethanolic extracts of selected marine algae samples, separated on chromatographic plates, with nitric/nitrous acid was investigated. The nature of bioactive compounds in the marine algae extracts was characterised using UV absorption spectra before and after reaction with diluted nitric acid, and from the characteristic colour reaction after derivatization with anisaldehyde. It was found that diterpenes from Dictyota dichotoma, an edible brown algae, and sterols from green algae Caulerpa brachypus, bind nitric oxide and may act as a nitric oxide carrier. Although the carotenoid fucoxanthin, found in all brown marine algae also binds nitric oxide, the bonds between nitrogen and the fucoxanthin molecule are much stronger. Further studies are required to evaluate the effects of diterpenes from Dictyota dichotoma and sterols from green algae Caulerpa brachypus to see if they have beneficial cardiovascular effects. The method reported here should prove useful in screening large numbers of algae species for compounds with cardiovascular activity. Copyright © 2018 Elsevier B.V. All rights reserved.

Spectrofluorimetric determination of thallium in silicate rocks with rhodamine b in the presence of aluminum chloride

USGS Publications Warehouse

Shnepfe, M.M.

1975-01-01

A sensitive spectrofluorimetric procedure with rhodamine B in the presence of aluminum chloride is given for determining submicrogram and microgram quantities of thallium in silicate rocks. Samples are decomposed with a mixture of hydrofluoric and nitric acids and then treated with hydrochloric acid. Thallium is extracted as its dithizonate with chloroform from an alkaline medium containing ascorbate, citrate, and cyanide and then back-extracted with dilute nitric acid. After destruction of the organic matter and treatment with bromine, hydrochloric acid, aluminum chloride, and rhodamine B, the {A table is presented}. ?? 1975.

Impact of sulfuric and nitric acids on carbonate dissolution, and the associated deficit of CO2 uptake in the upper-middle reaches of the Wujiang River, China

NASA Astrophysics Data System (ADS)

Huang, Qi-bo; Qin, Xiao-qun; Liu, Peng-yu; Zhang, Lian-kai; Su, Chun-tian

2017-08-01

Carbonate weathering and the CO2 consumption in karstic area are extensive affected by anthropogenic activities, especially sulfuric and nitric acids usage in the upper-middle reaches of Wujiang River, China. The carbonic acid would be substituted by protons from sulfuric and nitric acids which can be reduce CO2 absorption. Therefore, The goal of this study was to highlight the impacts of sulfuric and nitric acids on carbonate dissolution and the associated deficit of CO2 uptaking during carbonate weathering. The hydrochemistries and carbon isotopic signatures of dissolved inorganic carbon from groundwater were measured during the rainy season (July; 41 samples) and post-rainy season (October; 26 samples). Our results show that Ca2 + and Mg2 + were the dominant cations (55.87-98.52%), and HCO3- was the dominant anion (63.63-92.87%). The combined concentrations of Ca2 + and Mg2 + commonly exceeded the equivalent concentration of HCO3-, with calculated [Ca2 + + Mg2 +]/[HCO3-] equivalent ratios of 1.09-2.12. The mean measured groundwater δ13CDIC value (- 11.38‰) was higher than that expected for carbonate dissolution mediated solely by carbonic acid (- 11.5‰), and the strong positive correlation of these values with [SO42 - + NO3-]/HCO3- showed that additional SO42 - and NO3- were required to compensate for this cation excess. Nitric and sulfuric acids are, therefore, suggested to have acted as the additional proton-promoted weathering agents of carbonate in the region, alongside carbonic acid. The mean contribution of atmospheric/pedospheric CO2 to the total aquatic HCO3- decreased by 15.67% (rainy season) and 14.17% (post-rainy season) due to the contributions made by these acids. The annual mean deficit of soil CO2 uptake by carbonate weathering across the study area was 14.92%, which suggests that previous workers may have overestimated the absorption of CO2 by carbonate weathering in other karstic areas worldwide.

Impact of sulfuric and nitric acids on carbonate dissolution, and the associated deficit of CO2 uptake in the upper-middle reaches of the Wujiang River, China.

PubMed

Huang, Qi-Bo; Qin, Xiao-Qun; Liu, Peng-Yu; Zhang, Lian-Kai; Su, Chun-Tian

2017-08-01

Carbonate weathering and the CO 2 consumption in karstic area are extensive affected by anthropogenic activities, especially sulfuric and nitric acids usage in the upper-middle reaches of Wujiang River, China. The carbonic acid would be substituted by protons from sulfuric and nitric acids which can be reduce CO 2 absorption. Therefore, The goal of this study was to highlight the impacts of sulfuric and nitric acids on carbonate dissolution and the associated deficit of CO 2 uptaking during carbonate weathering. The hydrochemistries and carbon isotopic signatures of dissolved inorganic carbon from groundwater were measured during the rainy season (July; 41 samples) and post-rainy season (October; 26 samples). Our results show that Ca 2+ and Mg 2+ were the dominant cations (55.87-98.52%), and HCO 3 - was the dominant anion (63.63-92.87%). The combined concentrations of Ca 2+ and Mg 2+ commonly exceeded the equivalent concentration of HCO 3 - , with calculated [Ca 2+ +Mg 2+ ]/[HCO 3 - ] equivalent ratios of 1.09-2.12. The mean measured groundwater δ 13 C DIC value (-11.38‰) was higher than that expected for carbonate dissolution mediated solely by carbonic acid (-11.5‰), and the strong positive correlation of these values with [SO 4 2- +NO 3 - ]/HCO 3 - showed that additional SO 4 2- and NO 3 - were required to compensate for this cation excess. Nitric and sulfuric acids are, therefore, suggested to have acted as the additional proton-promoted weathering agents of carbonate in the region, alongside carbonic acid. The mean contribution of atmospheric/pedospheric CO 2 to the total aquatic HCO 3 - decreased by 15.67% (rainy season) and 14.17% (post-rainy season) due to the contributions made by these acids. The annual mean deficit of soil CO 2 uptake by carbonate weathering across the study area was 14.92%, which suggests that previous workers may have overestimated the absorption of CO 2 by carbonate weathering in other karstic areas worldwide. Copyright © 2017 Elsevier B.V. All rights reserved.

Material Compatibility Evaluation for DWPF Nitric-Glycolic Acid - Literature Review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mickalonis, J. I.; Skidmore, T. E.

Glycolic acid is being evaluated as an alternative for formic and nitric acid in the DWPF flowsheet. Demonstration testing and modeling for this new flowsheet has shown that glycolic acid and glycolate has a potential to remain in certain streams generated during the production of the nuclear waste glass. A literature review was conducted to assess the impact of glycolic acid on the corrosion of the materials of construction for the DWPF facility as well as facilities downstream which may have residual glycolic acid and glycolates present. The literature data was limited to solutions containing principally glycolic acid. The reportedmore » corrosion rates and degradation characteristics have shown the following for the materials of construction.« less

The 1980 stratospheric-tropospheric exchange experiment

NASA Technical Reports Server (NTRS)

Margozzi, A. P. (Editor)

1983-01-01

Data are presented from the Stratospheric-Tropospheric Water Vapor Exchange Experiment. Measurements were made during 11 flights of the NASA U-2 aircraft which provided data from horizontal traverser and samplings in and about the tops of extensive cirrus-anvil clouds produced by overshooting cumulus turrets. Aircraft measurements were made of water vapor, ozone, ambient and cloud top temperature, fluorocarbons, nitrous oxide, nitric acid, aerosols, and ice crystal populations. Balloonsondes were flown about twice daily providing data on ozone, wind fields, pressure and temperature to altitudes near 30 km. Satellite photography provided detailed cloud and cloud top temperature information. Descriptions of individual experiments and detailed compilations of all results are provided.

Ammonium Nitrate Formation near the Colorado Front Range

NASA Astrophysics Data System (ADS)

Middlebrook, A. M.; Bahreini, R.; Brock, C. A.; Brown, S. S.; Cozic, J.; Frost, G. J.; Langford, A. O.; Lerner, B. M.; Matthew, B.; McKeen, S. A.; Neuman, J.; Nowak, J. B.; Peischl, J. W.; Quinn, P.; Ryerson, T. B.; Schultz, K.; Stark, H.; Trainer, M.; Wagner, N.; Williams, E. J.; Wollny, A. G.

2009-12-01

A significant air quality issue during wintertime temperature inversions along the Colorado Front Range urban corridor is the infamous “Brown Cloud” which is dominated by ammonium nitrate particles. Aerosol composition, size distribution, and gas phase measurements were obtained along with meteorology in Boulder-based ground studies during the winters of 2005 and 2009 and in an airborne survey over the Colorado Front Range urban corridor and northeastern Colorado on April 1, 2008. New in these campaigns was the fast time response data which showed that nitric acid was partitioned mainly into the aerosol phase as ammonium nitrate. During the survey flight, ammonium nitrate mass concentrations were highest on the west side of the urban corridor whereas nitrogen oxide concentrations were highest directly west and south of Denver. Nitric acid concentrations were highest south of the city. The calculated equilibrium gas phase ammonia was highest close to the ground directly around large feed lots near Brush and west of Greeley. These differences are consistent with what is known about the locations of emission sources, the predominant flow during the experiments, and the chemistry. Indeed, the ammonia emissions in the northern part of the region are sufficiently high to cause ammonium nitrate formation to be limited by nitric acid whereas in the southern part of the region ammonium nitrate formation was limited by low ammonia emissions. Although NOx (NO + NO2) emissions in the region are much larger than those for ammonia, NOx must be converted into nitric acid in order for ammonium nitrate to form. In the survey data, aerosol nitrate was correlated with the daytime nitric acid production rate but with higher slopes in the northern parts of the region. In the longer Boulder datasets, the calculated daytime production rate was slow and comparable to nighttime heterogeneous production via N2O5 hydrolysis. During periods of low aerosol surface area, daytime and nighttime production of nitric acid resulted in freshly formed ammonium nitrate particles. These results suggest that reductions in NOx emissions along the northern part of the region are likely to decrease the prevalence of the Brown Cloud.

Soil acidification from atmospheric ammonium sulphate in forest canopy throughfall

NASA Astrophysics Data System (ADS)

van Breemen, N.; Burrough, P. A.; Velthorst, E. J.; van Dobben, H. F.; de Wit, Toke; Ridder, T. B.; Reijnders, H. F. R.

1982-10-01

Acid rain commonly has high concentrations of dissolved SO2-4, NH+4 and NO-3. Sulphuric and nitric acids are usually considered to be the acidic components, whereas ammonium has a tendency to increase the pH of rainwater1. Ammonium can be transformed to nitric acid in soil but this source of acidity is generally less important than wet and dry deposition of free acids2,3. Here we describe the occurrence of high concentrations of ammonium in canopy throughfall (rainwater falling through the tree canopy) and stemflow in woodland areas in the Netherlands, resulting in acid inputs to soils two to five times higher than those previously described for acid atmospheric deposition2-5. The ammonium is present as ammonium sulphate, which probably forms by interaction of ammonia (volatilized from manure) with sulphur dioxide (from fossil fuels), on the surfaces of vegetation. After leaching by rainwater the ammonium sulphate reaching the soil oxidizes rapidly to nitric and sulphuric acid, producing extremely low pH values (2.8-3.5) and high concentrations of dissolved aluminium in the non-calcareous soils studied. Deposition of ammonium sulphate on the surfaces of vegetation and its environmental consequences are probably most important in areas with intensive animal husbandry.

Methods of producing cesium-131

DOEpatents

Meikrantz, David H; Snyder, John R

2012-09-18

Methods of producing cesium-131. The method comprises dissolving at least one non-irradiated barium source in water or a nitric acid solution to produce a barium target solution. The barium target solution is irradiated with neutron radiation to produce cesium-131, which is removed from the barium target solution. The cesium-131 is complexed with a calixarene compound to separate the cesium-131 from the barium target solution. A liquid:liquid extraction device or extraction column is used to separate the cesium-131 from the barium target solution.

Minutes of the Explosives Safety Seminar (25th) Held in Anaheim, California on 18-20 August 1992. Volume 1

DTIC Science & Technology

1992-08-20

project. There is no doubt that we would have otherwise spent many years in proving project feasibility and trialing the specific demilitarisation...SUCH ROCKET MOTORS AS THE ONE USED IN THE BULLPUP SYSTEM WERE CONSIDERED. A. DRAINING AND NEUTRALIZING THE OXIDIZER BY CAUSTIC SODA AND THEN SIMPLE...INHIBITED RED FUMING NITRIC ACID WAS DETECTED IN SMALL AMOUNTS. 482 CONSEQUENTLY. THE "EMPTY" CASES WERE PLACED INTO A TANK CONTAINING WATER AND CAUSTIC

The Removal of NOx Using a Pulsed Streamer Corona Discharge in the Presence of Ethylene

DTIC Science & Technology

1996-07-25

be a stratospheric ozone destructor and a greenhouse gas (U.S EPA, 1993). Nitric oxide (NO) is an odorless gas and is only slightly soluble in water...gas can be bubbled for humidification , 5) flow meters, valves, and mass flow controllers, and 6) a stainless steel mixing chamber upstream from the...Reduction of Acid and Greenhouse Gases in Combustion of Flue Gases", Non-Thermal Plasma Techniques for Pollution Control, Part A, Eds: Penetrante

Uranyl nitrate hexahydrate solubility in nitric acid and its crystallization selectivity in the presence of nitrate salts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burns, Jonathan D.; Moyer, Bruce A.

The solubility of uranyl nitrate hexahydrate was determined as a function of nitric acid concentration and temperature, and the crystallization yield was calculated. Results showed an increase in crystal formation at lower initial nitric acid concentrations upon cooling a saturated solution of U(VI) from 50 °C to 2 °C, with over 70% recovery of U(VI) mass at all nitric acid concentrations and nearly quantitative recovery starting at 4 M HNO 3. A direct correlation between the change in mother liquor volume percent and U mass removal percent was observed. By reducing the cooling rate from roughly 4.0 °C/min to 0.22more » °C/min, the separation factor was increased from 3.88 to 15.7 to greater than 81 for the separation of U(VI) from Sr, Cs, and Nd. At the slower cooling rate, the separation factors were measured as a function of acidity for 2.0–4.3 M HNO 3, showing a decrease in selectivity with a decrease in the acidity. There was also no indication that tetravalent metal double-salt precipitation occurred with either Zr 4+ or Ce 4+. Here, these results indicate that a high-yield, high purity hexavalent actinide crystallization scheme may offer attractive benefits for nuclear-fuel recycle in that only a single very simple and well-understood technology is employed, and the use of organic compounds and solvents is avoided.« less

Uranyl nitrate hexahydrate solubility in nitric acid and its crystallization selectivity in the presence of nitrate salts

DOE PAGES

Burns, Jonathan D.; Moyer, Bruce A.

2017-10-23

The solubility of uranyl nitrate hexahydrate was determined as a function of nitric acid concentration and temperature, and the crystallization yield was calculated. Results showed an increase in crystal formation at lower initial nitric acid concentrations upon cooling a saturated solution of U(VI) from 50 °C to 2 °C, with over 70% recovery of U(VI) mass at all nitric acid concentrations and nearly quantitative recovery starting at 4 M HNO 3. A direct correlation between the change in mother liquor volume percent and U mass removal percent was observed. By reducing the cooling rate from roughly 4.0 °C/min to 0.22more » °C/min, the separation factor was increased from 3.88 to 15.7 to greater than 81 for the separation of U(VI) from Sr, Cs, and Nd. At the slower cooling rate, the separation factors were measured as a function of acidity for 2.0–4.3 M HNO 3, showing a decrease in selectivity with a decrease in the acidity. There was also no indication that tetravalent metal double-salt precipitation occurred with either Zr 4+ or Ce 4+. Here, these results indicate that a high-yield, high purity hexavalent actinide crystallization scheme may offer attractive benefits for nuclear-fuel recycle in that only a single very simple and well-understood technology is employed, and the use of organic compounds and solvents is avoided.« less

Analysis of Antarctic Denitrification in 2003 Winter Observed by ILAS-II Onboard the ADEOS-II Satellite

NASA Astrophysics Data System (ADS)

Nakajima, H.; Saeki, K.; Sugita, T.

2005-12-01

Polar Stratospheric Clouds (PSC) play an important role in ozone destruction in both Arctic and Antarctic stratosphere in winter. They take up gas-phase nitric acid (HNO3) and grow up when temperature is below nitric acid saturation temperature (TNAT). When PSC becomes large, it starts to descend and nitric acid is removed from the air mass, resulting in denitrification. The Improved Limb Atmospheric Spectrometer-II (ILAS-II) onboard the Advanced Earth Observing Satellite-II (ADEOS-II) successfully made measurements for the whole Antarctic winter in 2003. ILAS-II measured vertical profiles of O3, HNO3, NO2, H2O, N2O, CH4, ClONO2, N2O5, etc. in addition to the aerosol extinction coefficients at 780 nm. In this study, we analyzed denitrification from ILAS-II HNO3 and N2O data in regard to temperature history on the trajectory. The quantity of denitrification was estimated from the difference between measured HNO3 and HNO3* assumed from HNO3-- N2O correlation. In this analysis, it was found that denitrification was observed only for those airmass that experienced temperature below TICE (ice saturation temperature) in late June, 2003. In late July, it was found that most airmass inside the polar vortex was denitrified regardless of temperature history. This suggests that permanent denitrification has occurred in June-July period. The transition of relationship between denitrification and airmass temperature history was discovered from the ILAS-II data. Also, major types of PSC have found to be changed from nitric acid trihydrate (NAT) in June to ice in July, from the ILAS-II data. This is considered to be due to the lack of nitric acid in the airmass due to the denitrification in July.

Turbulent acidic jets and plumes injected into an alkaline environment

NASA Astrophysics Data System (ADS)

Ulpre, Hendrik

2012-11-01

The characteristics of a strong acidic turbulent jet or plume injected into an alkaline environment comprising of a weak/strong base are examined theoretically and experimentally. A chemistry model is developed to understand how the pH of a fluid parcel of monoprotic acid changes as it is diluted and reacts with the ambient fluid. A standard fluid model, based on a top-hat model for acid concentration and velocity is used to express how the dilution of acid varies with distance from the point of discharge. These models are applied to estimate the point of neutralisation and the travel time with distance within the jet/plume. An experimental study was undertaken to test the theoretical results. These experiments involved injecting jets or vertical plumes of dilute nitric acid into a large tank containing a variety of base salts dissolved in water. The injected fluid contained litmus indicator dye which showed a change in colour from red to blue close to the point of neutralisation. In order to obtain a range of neutralisation distances, additional basic salts were added to the water to increase its pH buffering capacity. The results are applied to discuss the environmental implications of an acidic jet/plume injected into the sea off the South East coast of Great Britain.

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of whole-water recoverable arsenic, boron, and vanadium using inductively coupled plasma-mass spectrometry

USGS Publications Warehouse

Garbarino, John R.

2000-01-01

Analysis of in-bottle digestate by using the inductively coupled plasma?mass spectrometric (ICP?MS) method has been expanded to include arsenic, boron, and vanadium. Whole-water samples are digested by using either the hydrochloric acid in-bottle digestion procedure or the nitric acid in-bottle digestion procedure. When the hydrochloric acid in-bottle digestion procedure is used, chloride must be removed from the digestate by subboiling evaporation before arsenic and vanadium can be accurately determined. Method detection limits for these elements are now 10 to 100 times lower than U.S. Geological Survey (USGS) methods using hydride generation? atomic absorption spectrophotometry (HG? AAS) and inductively coupled plasma? atomic emission spectrometry (ICP?AES), thus providing lower variability at ambient concentrations. The bias and variability of the methods were determined by using results from spike recoveries, standard reference materials, and validation samples. Spike recoveries in reagent-water, surface-water, ground-water, and whole-water recoverable matrices averaged 90 percent for seven replicates; spike recoveries were biased from 25 to 35 percent low for the ground-water matrix because of the abnormally high iron concentration. Results for reference material were within one standard deviation of the most probable value. There was no significant difference between the results from ICP?MS and HG?AAS or ICP?AES methods for the natural whole-water samples that were analyzed.

[Effects of soy bean isoflavone on inhibition of benign prostatic hyperplasia and the expressions of NO and NOS of rats].

PubMed

Yang, Aiqing; Ren, Guofeng; Tang, Ling; Jiang, Weiwei

2009-03-01

To explore the inhibitive effect of soybean isoflavone on the prostatic hyperplasia on the expressions of nitric oxid and nitric oxide synthase in the prostatic hyperplasia rats. Subcutaneously injected testosterone propionate were to induce prostate hyperplasia in rats. The changes of prostate wet weight, prostatic index, liver index, the changes of some biochemical indexes in rat prostate tissue in the control and the treatment, the low, moderate, high dose groups of soybean isoflavone groups were observed. The prostate wet weight and prostatic index in all dose groups were merely lower than those in the treatment and the moderate groups were lowest in all dose group. There were no significant differences in liver index, urea nitrogen, glutamic-pyruvic transaminase of each group. Acid phosphatase, prostatic acid phosphatase and lactate dehydrogenase in all dose groups were merely lower than those in the treatment group. Nitric oxide and nitric oxide synthase in all dose groups were merely higher than those in the treatment group. Soybean isoflavone could inhibit prostate hyperplasia and increase the expressions of nitric oxide and nitric oxide synthase in rats.

Evaluation of the Magnesium Hydroxide Treatment Process for Stabilizing PFP Plutonium/Nitric Acid Solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gerber, Mark A.; Schmidt, Andrew J.; Delegard, Calvin H.

2000-09-28

This document summarizes an evaluation of the magnesium hydroxide [Mg(OH)2] process to be used at the Hanford Plutonium Finishing Plant (PFP) for stabilizing plutonium/nitric acid solutions to meet the goal of stabilizing the plutonium in an oxide form suitable for storage under DOE-STD-3013-99. During the treatment process, nitric acid solutions bearing plutonium nitrate are neutralized with Mg(OH)2 in an air sparge reactor. The resulting slurry, containing plutonium hydroxide, is filtered and calcined. The process evaluation included a literature review and extensive laboratory- and bench-scale testing. The testing was conducted using cerium as a surrogate for plutonium to identify and quantifymore » the effects of key processing variables on processing time (primarily neutralization and filtration time) and calcined product properties.« less

Purification of Carbon Nanotubes: Alternative Methods

NASA Technical Reports Server (NTRS)

Files, Bradley; Scott, Carl; Gorelik, Olga; Nikolaev, Pasha; Hulse, Lou; Arepalli, Sivaram

2000-01-01

Traditional carbon nanotube purification process involves nitric acid refluxing and cross flow filtration using surfactant TritonX. This is believed to result in damage to nanotubes and surfactant residue on nanotube surface. Alternative purification procedures involving solvent extraction, thermal zone refining and nitric acid refiuxing are used in the current study. The effect of duration and type of solvent to dissolve impurities including fullerenes and P ACs (polyaromatic compounds) are monitored by nuclear magnetic reasonance, high performance liquid chromatography, and thermogravimetric analysis. Thermal zone refining yielded sample areas rich in nanotubes as seen by scanning electric microscopy. Refluxing in boiling nitric acid seem to improve the nanotube content. Different procedural steps are needed to purify samples produced by laser process compared to arc process. These alternative methods of nanotube purification will be presented along with results from supporting analytical techniques.

Nitric-glycolic flowsheet testing for maximum hydrogen generation rate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martino, C. J.; Newell, J. D.; Williams, M. S.

The Defense Waste Processing Facility (DWPF) at the Savannah River Site is developing for implementation a flowsheet with a new reductant to replace formic acid. Glycolic acid has been tested over the past several years and found to effectively replace the function of formic acid in the DWPF chemical process. The nitric-glycolic flowsheet reduces mercury, significantly lowers the chemical generation of hydrogen and ammonia, allows purge reduction in the Sludge Receipt and Adjustment Tank (SRAT), stabilizes the pH and chemistry in the SRAT and the Slurry Mix Evaporator (SME), allows for effective adjustment of the SRAT/SME rheology, and is favorablemore » with respect to melter flammability. The objective of this work was to perform DWPF Chemical Process Cell (CPC) testing at conditions that would bound the catalytic hydrogen production for the nitric-glycolic flowsheet.« less

Nitric acid and ammonia emissions from a mid-latitude prescribed wetlands fire

NASA Technical Reports Server (NTRS)

Lebel, P. J.; Cofer, W. R., III; Levine, J. S.; Vay, S. A.; Roberts, P. D.

1988-01-01

The first simultaneous measurements of gaseous nitric acid and ammonia in the smoke plume of a wetlands biomass burn were obtained. The measurements were made using tungsten oxide-coated diffusion denuder tubes from a helicopter during a prescribed burn on November 9, 1987, at the Merritt Island National Wildlife Refuge, located at the NASA John F. Kennedy Space Center, Florida. The mean NH3 and HNO3 mixing ratios measured in the smoke plume were 19 ppbv and 14 ppbv, respectively, both significantly higher than background mixing ratios. Nitric acid correlated well with carbon dioxide produced by the combustion. The mean CO2-normalized emission ratio for HNO3 was found to be 0.00012. Ammonia, however, dit not correlate well with CO2, suggesting a more complex relationship between combustion and production/release of NH3.

Effect of fatty acids on endothelium-dependent relaxation in the rabbit aorta.

PubMed

Edirisinghe, Indika; McCormick Hallam, Kellie; Kappagoda, C Tissa

2006-08-01

The metabolic syndrome, Type II (non-insulin-dependent) diabetes and obesity are associated with endothelial dysfunction and increased plasma concentrations of NEFAs (non-esterified fatty acids; free fatty acids). The present study was undertaken to define the inhibitory effects of saturated NEFAs on EDR (endothelium-dependent relaxation). Experiments were performed in rings of rabbit aorta to establish (i) dose-response relationships, (ii) the effect of chain length, (iii) the effect of the presence of double bonds, (iv) reversibility and time course of inhibition, and (v) the effect on nitric oxide production. Aortic rings were incubated (1 h) with NEFA-albumin complexes derived from lauric (C(12:0)), myristic (C(14:0)), palmitic (C(16:0)), stearic (C(18:0)) and linolenic (C(18:3)) acids. EDR induced by acetylcholine (0.1-10 mumol/l) was measured after pre-contraction with noradrenaline. Inhibition of EDR was dose-dependent (0.5-2 mmol/l NEFA), and the greatest inhibition (51%) was observed with stearic acid (2 mmol/l). Lauric acid had the smallest inhibitory effect. The inhibitory effects were always reversible and were evident after 15 min of incubation. Linolenic acid caused a significantly lower inhibition of EDR than stearic acid. SOD (superoxide dismutase) restored the inhibitory effect caused by NEFAs, suggesting the involvement of ROS (reactive oxygen species) in removing nitric oxide. The nitric oxide concentration measured after exposure of the rings to acetylcholine was lower after incubation with NEFAs than with Krebs buffer alone. This finding is consistent with removal of nitric oxide by ROS. This claim was supported by the demonstration of increased concentrations of nitrated tyrosine in the rings incubated with NEFAs.

Multi-elemental analysis of aqueous geological samples by inductively coupled plasma-optical emission spectrometry

USGS Publications Warehouse

Todorov, Todor I.; Wolf, Ruth E.; Adams, Monique

2014-01-01

Typically, 27 major, minor, and trace elements are determined in natural waters, acid mine drainage, extraction fluids, and leachates of geological and environmental samples by inductively coupled plasma-optical emission spectrometry (ICP-OES). At the discretion of the analyst, additional elements may be determined after suitable method modifications and performance data are established. Samples are preserved in 1–2 percent nitric acid (HNO3) at sample collection or as soon as possible after collection. The aqueous samples are aspirated into the ICP-OES discharge, where the elemental emission signals are measured simultaneously for 27 elements. Calibration is performed with a series of matrix-matched, multi-element solution standards.

Leaching of uranium from glass and ceramic foodware and decorative items

USGS Publications Warehouse

Landa, Edward R.; Councell, Terry B.

1992-01-01

Beginning as early as the first century A. D. and continuing until at least the 1970s, uranium was used as a coloring agent in glass and in ceramic glazes. The leaching of uranium from such items is of interest as some were designed for food storage or serving. Thirty-three glass items and two ceramic items were leached sequentially with deionized water, dilute acetic acid, and 1 M nitric acid to assess realistic and worst-case scenario leaching by foods and beverages. The maximum quantity of uranium leached from the uranium-bearing glasses was about 30 µg L-1, while that from the ceramic-glazed items was about 300,000 µg L-1.

Laboratory studies of stratospheric aerosol chemistry

NASA Technical Reports Server (NTRS)

Molina, Mario J.

1996-01-01

In this report we summarize the results of the two sets of projects funded by the NASA grant NAG2-632, namely investigations of various thermodynamic and nucleation properties of the aqueous acid system which makes up stratospheric aerosols, and measurements of reaction probabilities directly on ice aerosols with sizes corresponding to those of polar stratospheric cloud particles. The results of these investigations are of importance for the assessment of the potential stratospheric effects of future fleets of supersonic aircraft. In particular, the results permit to better estimate the effects of increased amounts of water vapor and nitric acid (which forms from nitrogen oxides) on polar stratospheric clouds and on the chemistry induced by these clouds.

Ameliorative Effect of Chronic Supplementation of Protocatechuic Acid Alone and in Combination with Ascorbic Acid in Aniline Hydrochloride Induced Spleen Toxicity in Rats.

PubMed

Khairnar, Upasana; Upaganlawar, Aman; Upasani, Chandrashekhar

2016-01-01

Background. Present study was designed to evaluate the protective effects of protocatechuic acid alone and in combination with ascorbic acid in aniline hydrochloride induced spleen toxicity in rats. Materials and Methods. Male Wistar rats of either sex (200-250 g) were used and divided into different groups. Spleen toxicity was induced by aniline hydrochloride (100 ppm) in drinking water for a period of 28 days. Treatment group received protocatechuic acid (40 mg/kg/day, p.o.), ascorbic acid (40 mg/kg/day, p.o.), and combination of protocatechuic acid (20 mg/kg/day, p.o.) and ascorbic acid (20 mg/kg/day, p.o.) followed by aniline hydrochloride. At the end of treatment period serum and tissue parameters were evaluated. Result. Rats supplemented with aniline hydrochloride showed a significant alteration in body weight, spleen weight, feed consumption, water intake, hematological parameters (haemoglobin content, red blood cells, white blood cells, and total iron content), tissue parameters (lipid peroxidation, reduced glutathione, and nitric oxide content), and membrane bound phosphatase (ATPase) compared to control group. Histopathology of aniline hydrochloride induced spleen showed significant damage compared to control rats. Treatment with protocatechuic acid along with ascorbic acid showed better protection as compared to protocatechuic acid or ascorbic acid alone in aniline hydrochloride induced spleen toxicity. Conclusion. Treatment with protocatechuic acid and ascorbic acid in combination showed significant protection in aniline hydrochloride induced splenic toxicity in rats.

Both sides now: the chemistry of clouds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwartz, S.E.

1984-01-01

Two complementary approaches to the study of the oxidation of SO/sub 2/ and NO/sub x/ to sulfuric and nitric acids as it occurs in liquid-water clouds are presented. The first approach relies upon laboratory determination of fundamental physical and chemical properties and evaluation of rates of dissolution and reaction for representative reagent concentrations and physical situations. The second approach consists of measuring concentrations of relevant reagent and product species and other pertinent quantities in and about clouds and of drawing inferences from these measurements about the rate and extent of processes responsible for establishing cloudwater composition. Based on laboratory studiesmore » the following inferences may be drawn: aqueous-phase oxidation of SO/sub 2/ by H/sub 2/O/sub 2/ or O/sub 3/ is sufficiently rapid to contribute to cloudwater acidity for representative concentrations of these oxidants; however, the rate of the O/sub 3/ reaction decreases strongly with decreasing pH and is of relatively little importance below about pH 4.5. Despite strong thermochemical driving force for oxidation of NO/sub 2/ to nitric acid in cloudwater, this reaction appears to be negligibly slow for representative concentrations of NO/sub 2/, largely because of the low Henry's law solubility of this species in water. These inferences gain support from field measurements of the composition of liquid water stratiform clouds at various locations in the eastern United States, which indicate that the fractional uptake of SO/sub 2/ (as SO/sub 4//sup =/) by cloudwater is frequently high, whereas a corresponding high fractional uptake of NO/sub x/ as NO/sub 3//sup -/ is never observed. A mutual exclusivity of gaseous SO/sub 2/ and dissolved H/sub 2/O/sub 2/ in clouds supports the inference that reaction of these species in clouds is rapid and represents a major process for cloudwater acidification. 143 references, 35 figures, 2 tables.« less

SELECTIVE SEPARATION OF URANIUM FROM THORIUM, PROTACTINIUM AND FISSION PRODUCTS BY PEROXIDE DISSOLUTION METHOD

DOEpatents

Seaborg, G.T.; Gofman, J.W.; Stoughton, R.W.

1959-08-18

A method is described for separating U/sup 233/ from thorium and fission products. The separation is effected by forming a thorium-nitric acid solution of about 3 pH, adding hydrogen peroxide to precipitate uranium and thorium peroxide, treating the peroxides with sodium hydroxide to selectively precipitate the uranium peroxide, and reacting the separated solution with nitric acid to re- precipitate the uranium peroxide.

Ruthenium oxide ion selective thin-film electrodes for engine oil acidity monitoring

NASA Astrophysics Data System (ADS)

Maurya, D. K.; Sardarinejad, A.; Alameh, K.

2015-06-01

We demonstrate the concept of a low-cost, rugged, miniaturized ion selective electrode (ISE) comprising a thin film RuO2 on platinum sensing electrode deposited using RF magnetron sputtered in conjunction with an integrated Ag/AgCl and Ag reference electrodes for engine oil acidity monitoring. Model oil samples are produced by adding nitric acid into fresh fully synthetic engine oil and used for sensor evaluation. Experimental results show a linear potential-versus-acid-concentration response for nitric acid concentration between 0 (fresh oil) to 400 ppm, which demonstrate the accuracy of the RuO2 sensor in real-time operation, making it attractive for use in cars and industrial engines.

METHOD OF SEPARATION

DOEpatents

Boyd, G.E.

1958-08-26

A process is presented fer separating uranium, plutonium, and fission products ions from uranyl nitrate solutions having a pH value between 1 and 3 obtained by dissolving neutron irradiated uranium. The method consists in passing such solutions through a bed of cation exchange resin, which may be a sulfonated phenol formaidehyde type. Following the adsorption step the resin is first treated with a solution of 0.2M to 0.3M sulfuric acid to desorb the uranium. Fission product ions are then desorbed by treating the resin in phosphoric acid and 1M in nitric acid. Lastly, the plutonium may be desorbed by treating the resin with a solution approximately 0.8M in phosphoric acid and 1M in nitric acid.

Measurements of tropospheric nitric acid over the Western United States and Northeastern Pacific Ocean

NASA Technical Reports Server (NTRS)

Lebel, P. J.; Huebert, B. J.; Schiff, H. I.; Vay, S. A.; Vanbramer, S. E.; Hastie, D. R.

1990-01-01

Over 240 measurements of nitric acid (HNO3) were made in the free troposphere as well as in the boundary layer. Marine HNO3 measurement results were strikingly similar to results from GAMETAG and other past atmospheric field experiments. The marine boundary layer HNO3 average, 62 parts-per-trillion by volume (pptv), was 1/3 lower than the marine free tropospheric average, 108 pptv, suggesting that the boundary layer is a sink for tropospheric nitric acid, probably by dry deposition. Nitric acid measurements on a nighttime continental flight gave a free tropospheric average of 218 pptv, substantially greater than the daytime continental free tropospheric 5-flight average of 61 pptv. However, the nighttime results may be influenced by highly convective conditions that existed from thunderstorms in the vicinity during that night flight. The continental boundary layer HNO3 average of 767 pptv is an order of magnitude greater than the free tropospheric average, indicating that the boundary layer is a source of free tropospheric HNO3. The distribution of continental boundary layer HNO3 data, from averages of 123 over rural Nevada and Utah to 1057 pptv in the polluted San Joaquin Valley of California suggest a close tie between boundary layer HNO3 and anthropogenic activity.

Application of physical adsorption thermodynamics to heterogeneous chemistry on polar stratospheric clouds

NASA Technical Reports Server (NTRS)

Elliott, Scott; Turco, Richard P.; Toon, Owen B.; Hamill, Patrick

1991-01-01

Laboratory isotherms for the binding of several nonheterogeneously active atmospheric gases and for HCl to water ice are translated into adsorptive equilibrium constants and surface enthalpies. Extrapolation to polar conditions through the Clausius Clapeyron relation yields coverage estimates below the percent level for N2, Ar, CO2, and CO, suggesting that the crystal faces of type II stratospheric cloud particles may be regarded as clean with respect to these species. For HCl, and perhaps HF and HNO3, estimates rise to several percent, and the adsorbed layer may offer acid or proton sources alternate to the bulk solid for heterogeneous reactions with stratospheric nitrates. Measurements are lacking for many key atmospheric molecules on water ice, and almost entirely for nitric acid trihydrate as substrate. Adsorptive equilibria enter into gas to particle mass flux descriptions, and the binding energy determines rates for desorption of, and encounter between, potential surface reactants.

WET FLUORIDE SEPARATION METHOD

DOEpatents

Seaborg, G.T.; Gofman, J.W.; Stoughton, R.W.

1958-11-25

The separation of U/sup 233/ from thorium, protactinium, and fission products present in neutron-irradiated thorium is accomplished by dissolving the irradiated materials in aqueous nitric acid, adding either a soluble fluoride, iodate, phosphate, or oxalate to precipltate the thorium, separating the precipltate from the solution, and then precipitating uranlum and protactinium by alkalizing the solution. The uranium and protactinium precipitate is removcd from the solution and dissolved in nitric acid. The uranyl nitrate may then be extracted from the acid solution by means of ether, and the protactinium recovered from the aqueous phase.

NITRIC ACID PICKLING PROCESS

DOEpatents

Boller, E.R.; Eubank, L.D.

1958-08-19

An improved process is described for the treatment of metallic uranium surfaces preparatory to being given hot dip coatings. The process consists in first pickling the uraniunn surInce with aqueous 50% to 70% nitric acid, at 60 to 70 deg C, for about 5 minutes, rinsing the acid solution from the uranium article, promptly drying and then passing it through a molten alkali-metal halide flux consisting of 42% LiCl, 53% KCla and 5% NaCl into a molten metal bath consisting of 85 parts by weight of zinc and 15 parts by weight of aluminum

Nitric oxide coupling to generate N2O promoted by a single-heme system as examined by density functional theory.

PubMed

Yi, Jun; Campbell, Adam L O; Richter-Addo, George B

2016-11-30

Bacteria utilize a heme/non-heme enzyme system to detoxify nitric oxide (NO) to N 2 O. In order to probe the capacity of a single-heme system to mediate this NO-to-N 2 O transformation, various scenarios for addition of electrons, protons, and a second NO molecule to a heme nitrosyl to generate N 2 O were explored by density functional theory calculations. We describe, utilizing this single-heme system, several stepwise intermediates along pathways that enable the critical N-N bond formation step yielding the desired Fe-N 2 O product. We also report a hitherto unreported directional second protonation that results in either productive N 2 O formation with loss of water, or formation of a non-productive hyponitrous acid adduct Fe{HONNOH}. Copyright © 2016 Elsevier Inc. All rights reserved.

Synthesis of SnO2 and Ag Nanoparticles from Electronic Wastes with the Assistance of Ultrasound and Microwaves

NASA Astrophysics Data System (ADS)

Cerchier, Pietrogiovanni; Dabalà, Manuele; Brunelli, Katya

2017-09-01

In this work, SnO2 and Ag nanoparticles were produced with a raw material nitric acid solution, which came from the leaching of printed circuit boards. First, a precursor of tin oxide was precipitated from the nitric acid solution by three different techniques: (I) conventional heating, (II) microwave irradiation, and (III) ultrasound treatment. Second, this precursor was transformed into tin oxide nanoparticles by heat treatment in a furnace. Third, hydrochloric acid was added to the nitric acid solution to induce the precipitation of silver chloride. Fourth, silver chloride was reduced to metallic silver nanoparticles in an ammonia solution using glucose syrup as both the reducing agent and the capping agent. The reduction reaction was carried out through (I) conventional heating, (II) microwave irradiation, and (III) ultrasound treatment. The nanoparticles were characterized by scanning electron microscope (SEM), x-ray diffractometer (XRD), infrared (IR)-spectroscopy, transmission electron microscope (TEM), ultraviolet (UV)-spectroscopy, and laser diffraction particle size analyzer.

The functionalization and characterization of multi-walled carbon nanotubes (MWCNTs)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdullah, Mohd Pauzi; Center of Water Analysis and Research; Zulkepli, Siti Aminah

2015-09-25

Functionalization is the process of introducing chemical functional groups on the surface of the material. In this study, a multi-walled carbon nanotube (MWCNTs) was functionalized by oxidation treatment using concentrated nitric acid. The functionalized and pristine MWCNTs were analyzed by using Fourier Transform Infrared Spectroscopy (FT-IR) and X-Ray Diffraction (XRD). The XRD patterns exhibit the graphitic properties for all samples. Besides, the XRD results also demonstrate that the percent of crystallinity of MWCNTs increases as the duration of acid treatment increases. The percent of crystallinity increases from 66% to 80% when the pristine MWCNT treated for 12 hours with additionalmore » 12 hours reflux process with nitric acid. The IR spectrum for the 12 hours-treated MWCNTs shows the formation of carboxyl functional group. Additional 12 hours reflux process with nitric acid on the 12 hours-treated MWCNTs have shown the loss of existing carboxyl group and only hydroxyl group formed.« less

METHOD OF RECOVERING PLUTONIUM VALUES FROM AQUEOUS SOLUTIONS BY CARRIER PRECIPITATION

DOEpatents

James, R.A.; Thompson, S.G.

1959-11-01

A process is presented for pretreating aqueous nitric acid- plutonium solutions containing a small quantity of hydrazine that has formed as a decomposition product during the dissolution of neutron-bombarded uranium in nitric acid and that impairs the precipitation of plutonium on bismuth phosphate. The solution is digested with alkali metal dichromate or potassium permanganate at between 75 and 100 deg C; sulfuric acid at approximately 75 deg C and sodium nitrate, oxaiic acid plus manganous nitrate, or hydroxylamine are added to the solution to secure the plutonium in the tetravalent state and make it suitable for precipitation on BiPO/sub 4/.

Alternative to Nitric Acid for Passivation of Stainless Steel Alloys

NASA Technical Reports Server (NTRS)

Lewis, Pattie L.; Kolody, Mark; Curran, Jerry

2013-01-01

Corrosion is an extensive problem that affects the Department of Defense (DoD) and National Aeronautics and Space Administration (NASA). The deleterious effects of corrosion result in steep costs, asset downtime affecting mission readiness, and safety risks to personnel. Consequently, it is vital to reduce corrosion costs and risks in a sustainable manner. The DoD and NASA have numerous structures and equipment that are fabricated from stainless steel. The standard practice for protection of stainless steel is a process called passivation. Typical passivation procedures call for the use of nitric acid; however, there are a number of environmental, worker safety, and operational issues associated with its use. Citric acid offers a variety of benefits including increased safety for personnel, reduced environmental impact, and reduced operational cost. DoD and NASA agreed to collaborate to validate citric acid as an acceptable passivating agent for stainless steel. This paper details our investigation of prior work developing the citric acid passivation process, development of the test plan, optimization of the process for specific stainless steel alloys, ongoing and planned testing to elucidate the process' resistance to corrosion in comparison to nitric acid, and preliminary results.

Balloon-borne measurements of aerosol, condensation nuclei, and cloud particles in the stratosphere at McMurdo Station, Antarctica, during the spring of 1987

NASA Technical Reports Server (NTRS)

Hofmann, D. J.; Rosen, J. M.; Harder, J. W.; Hereford, J. V.

1989-01-01

Measurements of the vertical profile of particles with condensation nuclei counters and eight channel aerosol detectors at McMurdo Station, Antarctica, in 1987 verified observations made in 1986 concerning the absence of upwelling in the polar vortex and the presence of a condensation nuclei layer in conjunction with the ozone hole region. New observations of a bimodal aerosol size distribution, consisting of a large-particle mode mixed in with the small-particle sulfate mode, at temperatures below -79 C are consistent with the presence of nitric acid-water particles at low concentrations. Higher concentrations of large particles were observed in association with nacreous clouds. An unusual particle layer which contained enhanced concentrations of both the small-particle (sulfate) mode and the large-particle (nitric acid) mode was detected at temperatures below -85 C, suggesting simultaneous nucleation and growth phenomena. The vortex condensation nuclei layer was observed to form at the same time as the ozone hole, indicating that formation of the layer is triggered by photochemical processes and may be important in controlling ozone depletion above 22 km.

Chemistry of chlorinated species in the Antarctic stratosphere

NASA Technical Reports Server (NTRS)

Molina, Mario J.; Tso, Tai-Ly; Wang, Frank C.-Y.

1988-01-01

The chemistry of Cl sub 2 O sub 2, the chlorine monoxide dimer, has been further investigated in order to better asses its potential role in catalytic ozone destruction cycles. The dimer has been generated in a flow system, in the 200 to 250 K temperature range, by using ozone and chlorine atoms as ClO precursors. The Cl-atoms are produced by a microwave discharge of either Cl sub 2, or of F sub 2 with subsequent addition of HCl. With this later scheme the dimer can be generated in the absence of Cl sub 2. The Fourier transform infrared spectra of the products clearly indicates the presence of two isomers, in agreement with earlier results (J. Phys. Shen., 91, 433, 1987). None of the observed IR bands can be attributed to a ClO-OClO adduct, since they all appear in the absence of any detectable amount of OCl. It is likely that the particles in the polar stratospheric clouds will have a relatively dilute nitric acid outer layer, even if the core is the nitric acid monohydrate, since the particles are in equilibrium with the ambient water vapor, which is present at levels of a few parts per million.

Re-construction layer effect of LiNi0.8Co0.15Mn0.05O2 with solvent evaporation process

NASA Astrophysics Data System (ADS)

Park, Kwangjin; Park, Jun-Ho; Hong, Suk-Gi; Choi, Byungjin; Heo, Sung; Seo, Seung-Woo; Min, Kyoungmin; Park, Jin-Hwan

2017-03-01

The solvent evaporation method on the structural changes and surface chemistry of the cathode and the effect of electrochemical performance of Li1.0Ni0.8Co0.15Mn0.05O2 (NCM) has been investigated. After dissolving of Li residuals using minimum content of solvent in order to minimize the damage of pristine material and the evaporation time, the solvent was evaporated without filtering and remaining powder was re-heated at 700 °C in oxygen environment. Two kinds of solvent, de-ionized water and diluted nitric acid, were used as a solvent. The almost 40% of Li residuals were removed using solvent evaporation method. The NCM sample after solvent evaporation process exhibited an increase in the initial capacity (214.3 mAh/g) compared to the pristine sample (207.4 mAh/g) at 0.1C because of enhancement of electric conductivity caused by decline of Li residuals. The capacity retention of NCM sample after solvent evaporation process (96.0% at the 50th cycle) was also improved compared to that of the pristine NCM sample (90.6% at the 50th cycle). The uniform Li residual layer after solvent treated and heat treatment acted like a coating layer, leading to enhance the cycle performance. The NCM sample using diluted nitric acid showed better performance than that using de-ionized water.

Ferulic Acid Alleviates Changes in a Rat Model of Metabolic Syndrome Induced by High-Carbohydrate, High-Fat Diet.

PubMed

Senaphan, Ketmanee; Kukongviriyapan, Upa; Sangartit, Weerapon; Pakdeechote, Poungrat; Pannangpetch, Patchareewan; Prachaney, Parichat; Greenwald, Stephen E; Kukongviriyapan, Veerapol

2015-08-04

Metabolic syndrome is a cluster of metabolic abnormalities characterized by obesity, insulin resistance, hypertension and dyslipidemia. Ferulic acid (FA) is the major phenolic compound found in rice oil and various fruits and vegetables. In this study, we examined the beneficial effects of FA in minimizing insulin resistance, vascular dysfunction and remodeling in a rat model of high-carbohydrate, high-fat diet-induced metabolic changes, which is regarded as an analogue of metabolic syndrome (MS) in man. Male Sprague-Dawley rats were fed a high carbohydrate, high fat (HCHF) diet and 15% fructose in drinking water for 16 weeks, where control rats were fed with standard chow diet and tap water. FA (30 or 60 mg/kg) was orally administered to the HCHF and control rats during the last six weeks of the study. We observed that FA significantly improved insulin sensitivity and lipid profiles, and reduced elevated blood pressure, compared to untreated controls (p < 0.05). Moreover, FA also improved vascular function and prevented vascular remodeling of mesenteric arteries. The effects of FA in HCHF-induced MS may be realized through suppression of oxidative stress by down-regulation of p47phox, increased nitric oxide (NO) bioavailability with up-regulation of endothelial nitric oxide synthase (eNOS) and suppression of tumor necrosis factor-α (TNF-α). Our results suggest that supplementation of FA may have health benefits by minimizing the cardiovascular complications of MS and alleviating its symptoms.

An iso-α-acid-rich extract from hops (Humulus lupulus) attenuates acute alcohol-induced liver steatosis in mice.

PubMed

Hege, Marianne; Jung, Finn; Sellmann, Cathrin; Jin, Chengjun; Ziegenhardt, Doreen; Hellerbrand, Claus; Bergheim, Ina

2018-01-01

Results of in vitro and in vivo studies suggest that consumption of beer is less harmful for the liver than consumption of spirits. It also has been suggested that secondary plant compounds derived from hops such as xanthohumol or iso-α-acids may have beneficial effects on the development of liver diseases of various etiologies. The aim of this study was to determine whether iso-α-acids consumed in doses achieved by "normal" beer consumption have beneficial effects on health. Female C57 Bl/6 J mice, pretreated for 4 d with an iso-α-acid-rich extract (∼30% iso-α-acids from hops, 0.75 mg/kg body weight), were fed one bolus of ethanol (6 g/kg body weight intragastric) or an iso-caloric maltodextrin solution. Markers of liver damage, toll-like receptor-4 signaling, and lipid peroxidation were determined. Furthermore, the effect of isohumulone on the lipopolysaccharide-dependent activation of J774 A.1 macrophages, used as a model of Kupffer cells, was determined. In the liver, acute ethanol administration led to a significant accumulation of fat (∼10-fold), which was accompanied by significantly higher inducible nitric oxide synthase protein level, elevated nitric oxide production, and increased plasminogen activator inhibitor 1 protein concentration when compared to controls. In mice pretreated with iso-α-acids, these effects of alcohol were markedly attenuated. Pretreatment of J774 A.1 macrophages with isohumulone significantly attenuated lipopolysaccharide-induced mRNA expression of inducible nitric oxide synthase and interleukin-6 as well as the release of nitric oxide. Taken together, iso-α-acids markedly attenuated the development of acute alcohol-induced damage in mice. Copyright © 2017 Elsevier Inc. All rights reserved.

Behavior of S.A.P. in the Mercury Catalyzed Nitric Acid Dissolution; COMPORTAMENTO DEL S.A.P. ALL'ATTACCO DI SOLUZIONI DI ACIDO NITRICO E NITRATO MERCURICO

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beone, G.

1963-10-01

Plates of S.A.P. (sintered Aluminum Powder) were dissolved under different conditions in a nitric acid solution containing mercuric nitrate as a catalyst. These experiments nim at establishing a head-end dissolution process for S.A.P. cladded uranium oxide fuels. The results of preliminary dissolution experiments on simulated fuel rods are also described. The behavior of S.A.P. in the mercury catalyzed nitric acid dissolutions differs strongly from the behavior of aluminum: reaction rates are very low for S.A.P. and the dissolution time borders on being unacceptable in an industrial process. Settling rates of suspended alumina are however favorable. A tentative head end flowsheetmore » lay out for PRO second core fuel elements is included. (auth)« less

How do Polar Stratospheric Clouds Form?

NASA Technical Reports Server (NTRS)

Drdla, Katja; Gandrud, Bruce; Baumgardner, Darrel; Herman, Robert; Gore, Warren J. (Technical Monitor)

2000-01-01

SOLVE measurements have been compared with results from a microphysical model to understand the composition and formation of the polar stratospheric clouds (PSCs) observed during SOLVE. Evidence that the majority of the particles remain liquid throughout the winter will be presented. However, a small fraction of the particles do freeze, and the presence of these frozen particles can not be explained by current theories, in which the only freezing mechanism is homogeneous freezing to ice below the ice frost point. Alternative formation mechanisms, in particular homogeneous freezing above the ice frost point and heterogeneous freezing, have been explored using the microphysical model. Both nitric acid trihydrate (NAT) and nitric acid dihydrate (NAD) have been considered as possible compositions for the solid-phase nitric acid aerosols. Comparisons between the model results and the SOLVE measurements will be used to constrain the possible formation mechanisms. Other effects of these frozen particles will also be discussed, in particular denitrification.

Ammonia Oxidation Plant at Plum Brook Ordnance Works

NASA Image and Video Library

1943-06-21

An ammonia oxidation plant at the Plum Brook Ordnance Works near Sandusky, Ohio, which later became the National Aeronautics and Space Administration’s (NASA) Plum Brook Station. During World War II the ordnance works produced trinitroluene (TNT), dinitrotoluene (DNT), and pentolite which were crated and shipped to an arsenal in Ravenna, Ohio. There, the explosives were packed into shells and sent to Allied forces overseas. Plum Brook was the third largest producer of TNT during World War II. Toluene, sulfuric acid, and nitric acid were used to manufacture the TNT. Nitric Acid is made by oxidizing ammonia, adding water, and concentrating it. The facility in this photograph was used for this oxidation. The structure included air compressors, filters, aftercoolers, power recovery systems, air receivers, heaters, ammonia gasifiers, gas mixers, cooler condensers, absorption columns, and bleaching columns. The Plum Brook Ordnance Works was shut down immediately after the war and remained vacant for the next ten years. NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA), acquired the 500 acres of the site in 1955 to build a nuclear test reactor. By 1963, the agency had acquired the entire 9000 acres from the Army. Almost all of the military facilities were removed in the early 1960s. Plum Brook Station contained over 30 test facilities at its peak in the late 1960s. Today there are four major facilities in operation.

Development of Acetic Acid Removal Technology for the UREX+Process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robert M. Counce; Jack S. Watson

2009-06-30

It is imperative that acetic acid is removed from a waste stream in the UREX+process so that nitric acid can be recycled and possible interference with downstreatm steps can be avoidec. Acetic acid arises from acetohydrozamic acid (AHA), and is used to suppress plutonium in the first step of the UREX+process. Later, it is hydrolyzed into hydroxyl amine nitrate and acetic acid. Many common separation technologies were examined, and solvent extraction was determined to be the best choice under process conditions. Solvents already used in the UREX+ process were then tested to determine if they would be sufficient for themore » removal of acetic acid. The tributyl phosphage (TBP)-dodecane diluent, used in both UREX and NPEX, was determined to be a solvent system that gave sufficient distribution coefficients for acetic acid in addition to a high separation factor from nitric acid.« less

Recovery of Water from Boiler Flue Gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edward Levy; Harun Bilirgen; Kwangkook Jeong

2008-09-30

This project dealt with use of condensing heat exchangers to recover water vapor from flue gas at coal-fired power plants. Pilot-scale heat transfer tests were performed to determine the relationship between flue gas moisture concentration, heat exchanger design and operating conditions, and water vapor condensation rate. The tests also determined the extent to which the condensation processes for water and acid vapors in flue gas can be made to occur separately in different heat transfer sections. The results showed flue gas water vapor condensed in the low temperature region of the heat exchanger system, with water capture efficiencies depending stronglymore » on flue gas moisture content, cooling water inlet temperature, heat exchanger design and flue gas and cooling water flow rates. Sulfuric acid vapor condensed in both the high temperature and low temperature regions of the heat transfer apparatus, while hydrochloric and nitric acid vapors condensed with the water vapor in the low temperature region. Measurements made of flue gas mercury concentrations upstream and downstream of the heat exchangers showed a significant reduction in flue gas mercury concentration within the heat exchangers. A theoretical heat and mass transfer model was developed for predicting rates of heat transfer and water vapor condensation and comparisons were made with pilot scale measurements. Analyses were also carried out to estimate how much flue gas moisture it would be practical to recover from boiler flue gas and the magnitude of the heat rate improvements which could be made by recovering sensible and latent heat from flue gas.« less

Thermal Stability of Acetohydroxamic Acid/Nitric Acid Solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rudisill, T.S.

2002-03-13

The transmutation of transuranic actinides and long-lived fission products in spent commercial nuclear reactor fuel has been proposed as one element of the Advanced Accelerator Applications Program. Preparation of targets for irradiation in an accelerator-driven subcritical reactor would involve dissolution of the fuel and separation of uranium, technetium, and iodine from the transuranic actinides and other fission products. The UREX solvent extraction process is being developed to reject and isolate the transuranic actinides in the acid waste stream by scrubbing with acetohydroxamic acid (AHA). To ensure that a runaway reaction will not occur between nitric acid and AHA, an analoguemore » of hydroxyl amine, thermal stability tests were performed to identify if any processing conditions could lead to a runaway reaction.« less

Two-step extraction method for lead isotope fractionation to reveal anthropogenic lead pollution.

PubMed

Katahira, Kenshi; Moriwaki, Hiroshi; Kamura, Kazuo; Yamazaki, Hideo

2018-05-28

This study developed the 2-step extraction method which eluted the Pb adsorbing on the surface of sediments in the first solution by aqua regia and extracted the Pb absorbed inside particles into the second solution by mixed acid of nitric acid, hydrofluoric acid and hydrogen peroxide solution. We applied the method to sediments in the enclosed water area and found out that the isotope ratios of Pb in the second solution represented those of natural origin. This advantage of the method makes it possible to distinguish the Pb between natural origin and anthropogenic source on the basis of the isotope ratios. The results showed that the method was useful to discuss the Pb sources and that anthropogenic Pb in the sediment samples analysed was mainly derived from China because of transboundary air pollution.

Extraction of diatoms from (cotton) clothing for forensic comparisons.

PubMed

Uitdehaag, Stefan; Dragutinovic, Aleksandar; Kuiper, Irene

2010-07-15

Diatoms in clothing can be used to determine contact with surface water and contact with a specific water source, which can help link suspects to crime scenes. However, for the study of diatoms it is imperative that they are first extracted from the clothing under investigation. In this study we tested three methods for extracting diatoms from cotton clothing: rinsing with water (RW), rinsing with ethanol (RE) and the dissolution of cotton with nitric and sulphuric acid (DI). The DI method produced the highest average yield and can be used to determine contact with water. The RE method extracted reproducible numbers of diatoms from two different T-shirts and the resulting species compositions were similar to their relevant reference water samples. Therefore, we present rinsing with ethanol as an effective extraction method for the qualitative and quantitative analysis of diatoms in (cotton) clothing. (c) 2010 Elsevier Ireland Ltd. All rights reserved.

Antarctic ozone - Meteoric control of HNO3

NASA Technical Reports Server (NTRS)

Prather, Michael J.; Rodriguez, Jose M.

1988-01-01

Atmospheric circulation leads to an accumulation of debris from meteors in the Antarctic stratosphere at the beginning of austral spring. The major component of meteoric material is alkaline, comprised predominantly of the oxides of magnesium and iron. These metals may neutralize the natural acidity of stratospheric aerosols, remove nitric acid from the gas phase, and bond it as metal nitrates in the aerosol phase. Removal of nitric acid vapor has been previously shown to be a critical link in the photochemical depletion of ozone in the Antarctic spring, by allowing for increased catalytic loss from chlorine and bromine.

Pre Conference Hazardous Materials Workshop, West/East Coast Safety Conference, held 3-4 October/31 October - 1 November 1981,

DTIC Science & Technology

1981-01-01

itation and ulceration of skin Blacher,. picklers (nicals). refiners (metals). tinners. c,".:mical manufactur- ing Hydrofluoric X Severe burning of skin...strong solutions are used) DNc,.g, felt hat industry Nitric X Severe skin burns and ulcers Nitric acid worker%, electroplaters. met- al refincr, acid...Fertilije, makers, gr:cultural workers. Calcium cyanamide alkali salt makers Calcium oxide, carbon- X Dermatitis,. burns , or ulcers Lime %orkers

New Polymer Coatings for Chemically Selective Mass Sensors

NASA Technical Reports Server (NTRS)

Sims, S. C.; Wright, Cassandra; Cobb, J.; McCalla, T.; Revelle, R.; Morris, V. R.; Pollack, S. K.

1997-01-01

There is a current need to develop sensitive and chemically specific sensors for the detection of nitric acid for in-situ measurements in the atmosphere. Polymer coatings have been synthesized and tested for their sensitivity and selectivity to nitric acid. A primary requirement for these polymers is detectability down to the parts per trillion range. The results of studies using these polymers as coatings for quartz crystal microbalances (QCM) and surface acoustic wave (SAW) devices will be presented.

Corrosion-Resistant Ti- xNb- xZr Alloys for Nitric Acid Applications in Spent Nuclear Fuel Reprocessing Plants

NASA Astrophysics Data System (ADS)

Manivasagam, Geetha; Anbarasan, V.; Kamachi Mudali, U.; Raj, Baldev

2011-09-01

This article reports the development, microstructure, and corrosion behavior of two new alloys such as Ti-4Nb-4Zr and Ti-2Nb-2Zr in boiling nitric acid environment. The corrosion test was carried out in the liquid, vapor, and condensate phases of 11.5 M nitric acid, and the potentiodynamic anodic polarization studies were performed at room temperature for both alloys. The samples subjected to three-phase corrosion testing were characterized using scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDAX). As Ti-2Nb-2Zr alloy exhibited inferior corrosion behavior in comparison to Ti-4Nb-4Zr in all three phases, weldability and heat treatment studies were carried out only on Ti-4Nb-4Zr alloy. The weldability of the new alloy was evaluated using tungsten inert gas (TIG) welding processes, and the welded specimen was thereafter tested for its corrosion behavior in all three phases. The results of the present investigation revealed that the newly developed near alpha Ti-4Nb-4Zr alloy possessed superior corrosion resistance in all three phases and excellent weldability compared to conventional alloys used for nitric acid application in spent nuclear reprocessing plants. Further, the corrosion resistance of the beta heat-treated Ti-4Nb-4Zr alloy was superior when compared to the sample heat treated in the alpha + beta phase.

A novel recovery method of copper from waste printed circuit boards by supercritical methanol process: Preparation of ultrafine copper materials.

PubMed

Xiu, Fu-Rong; Weng, Huiwei; Qi, Yingying; Yu, Gending; Zhang, Zhigang; Zhang, Fu-Shen; Chen, Mengjun

2017-02-01

In this study, supercritical methanol (SCM) process was successfully used for the preparation of ultrafine copper materials from waste printed circuit boards (PCBs) after nitric acid pretreatment. Waste PCBs were pretreated twice in nitric acid. Sn and Pb were recovered by the first nitric acid pretreatment. The leach liquor with a high concentration of copper ions after the second nitric acid leaching was subjected to SCM process. The mixture of Cu and Cu 2 O with poor uniformity of particle size was formed due to the effect of ferric iron contained in the leach liquor of waste PCBs, while more uniform and spherical Cu particles with high monodispersity and smaller size could be prepared after the removal of Fe. The size of Cu particles increased obviously with the decline of SCM temperature, and particles became highly aggregated when the reaction temperature decreased to 300°C. The size of Cu particles decreased markedly with the decrease of initial concentration of copper ion in the leach liquor of waste PCBs. It is believed that the process developed in this study is simple and practical for the preparation of ultrafine copper materials from waste PCBs with the aim of recycling these waste resources as a high value-added product. Copyright © 2016 Elsevier Ltd. All rights reserved.

Candida albicans Chitin Increases Arginase-1 Activity in Human Macrophages, with an Impact on Macrophage Antimicrobial Functions.

PubMed

Wagener, Jeanette; MacCallum, Donna M; Brown, Gordon D; Gow, Neil A R

2017-01-24

The opportunistic human fungal pathogen Candida albicans can cause a variety of diseases, ranging from superficial mucosal infections to life-threatening systemic infections. Phagocytic cells of the innate immune response, such as neutrophils and macrophages, are important first-line responders to an infection and generate reactive oxygen and nitrogen species as part of their protective antimicrobial response. During an infection, host cells generate nitric oxide through the enzyme inducible nitric oxide synthase (iNOS) to kill the invading pathogen. Inside the phagocyte, iNOS competes with the enzyme arginase-1 for a common substrate, the amino acid l-arginine. Several pathogenic species, including bacteria and parasitic protozoans, actively modulate the production of nitric oxide by inducing their own arginases or the host's arginase activity to prevent the conversion of l-arginine to nitric oxide. We report here that C. albicans blocks nitric oxide production in human-monocyte-derived macrophages by induction of host arginase activity. We further determined that purified chitin (a fungal cell wall polysaccharide) and increased chitin exposure at the fungal cell wall surface induces this host arginase activity. Blocking the C. albicans-induced arginase activity with the arginase-specific substrate inhibitor Nω-hydroxy-nor-arginine (nor-NOHA) or the chitinase inhibitor bisdionin F restored nitric oxide production and increased the efficiency of fungal killing. Moreover, we determined that C. albicans influences macrophage polarization from a classically activated phenotype toward an alternatively activated phenotype, thereby reducing antimicrobial functions and mediating fungal survival. Therefore, C. albicans modulates l-arginine metabolism in macrophages during an infection, potentiating its own survival. The availability and metabolism of amino acids are increasingly recognized as crucial regulators of immune functions. In acute infections, the conversion of the "conditionally essential" amino acid l-arginine by the inducible nitric oxide synthase to nitric oxide is a resistance factor that is produced by the host to fight pathogens. Manipulation of these host defense mechanisms by the pathogen can be key to successful host invasion. We show here that the human opportunistic fungal pathogen Candida albicans influences l-arginine availability for nitric oxide production by induction of the substrate-competing host enzyme arginase-1. This led to a reduced production of nitric oxide and, moreover, reduced eradication of the fungus by human macrophages. We demonstrate that blocking of host arginase-1 activity restored nitric oxide production and increased the killing potential of macrophages. These results highlight the therapeutic potential of l-arginine metabolism in fungal diseases. Copyright © 2017 Wagener et al.

Acid rain at Kennedy Space Center, Florida - Recent observations

NASA Technical Reports Server (NTRS)

Madsen, B. C.

1981-01-01

During the period July, 1977 to September, 1979, rainfall was collected in the vicinity of the Kennedy Space Center and subjected to appropriate chemical analysis for purposes of characterization of general composition and acidity. Results obtained form the basis for future comparisons, should significant alteration of the chemical composition of rain occur during the space shuttle era. Acidity extremes calculated on a monthly basis from event samples collected from five sites within a 200 sq km area varied from pH 5.1 in November, 1977, and April, 1978 to pH 4.3 in July, 1978 and July, 1979. Weighted average pH for the entire period was 4.55. Acidity was due to the presence of sulfuric and nitric acids. The mole ratio of excess SO4(-2):NO3(-) was typically greater than one. Monthly weighted average Cl(-) concentrations ranged from 20-240 micromoles/liter. The Cl(-):Na(+) ratio was slightly lower than that present in sea water.

Neutron activation analysis for antimetabolites. [in food samples

NASA Technical Reports Server (NTRS)

1973-01-01

Determination of metal ion contaminants in food samples is studied. A weighed quantity of each sample was digested in a concentrated mixture of nitric, hydrochloric and perchloric acids to affect complete solution of the food products. The samples were diluted with water and the pH adjusted according to the specific analysis performed. The samples were analyzed by neutron activation analysis, polarography, and atomic absorption spectrophotometry. The solid food samples were also analyzed by neutron activation analysis for increased sensitivity and lower levels of detectability. The results are presented in tabular form.

Nutritional Composition and Antioxidant Properties of Cucumis dipsaceus Ehrenb. ex Spach Leaf

PubMed Central

Chandran, Rahul; Nivedhini, V.; Parimelazhagan, Thangaraj

2013-01-01

The leaf of C. dipsaceus was evaluated for its nutritional and antioxidant properties. From the present investigation, significant amount of almost all essential amino acids and important minerals were quantified. Low levels of trypsin inhibitory units, phenolics, and tannins content were found as antinutritional content. Further, hot water extract of C. dipsaceus showed good activity especially in ABTS+, metal chelating, nitric oxide, and DPPH assays. Hence, the results conclude that C. dipsaceus could be a valuable nutraceutical supplement to the human diet. PMID:24288509

Adsorption of air pollutants on the grain surface of Japanese cedar pollen

NASA Astrophysics Data System (ADS)

Okuyama, Yuji; Matsumoto, Kiyoshi; Okochi, Hiroshi; Igawa, Manabu

The contaminants adsorbed on the surface of pollen may affect the development of hay fever, because the patients of the fever are larger in areas with much air pollution than in nonpolluted areas and the fine particles and gases are susceptible to deposit on the nasal cavities and eyes by their transfer on the pollen. Since Japanese cedar pollinosis is the most common hay fever in Japan, we analyzed the air pollutants adsorbed on the surface of dispersed Japanese cedar pollen in the urban and mountainous districts. Fine anthropogenic particles were significantly adsorbed and many elements were concentrated on the surface of the pollen in the urban site of Yokohama, while they were not concentrated on the surface of the pollen collected at a mountainous site. The acid gases are also adsorbed and acidify the surface, and their amounts increase with their concentrations in the ambient air. The high adsorption of nitric acid on the pollen determined by an exposure experiment of nitric acid gas suggests that nitric acid is dissolved in the inner part of the pollen. The adsorption amounts of the gases on the pollen were especially greater than those on other natural particles, humic acid and yellow sand.

Electrothermal vaporization of mineral acid solutions in inductively coupled plasma mass spectrometry: comparison with sample nebulization

NASA Astrophysics Data System (ADS)

Mora, Juan; Gras, Luis; van Veen, Eric H.; de Loos-Vollebregt, Margaretha T. C.

1999-06-01

The analytical behaviour of an electrothermal vaporization (ETV) device for the introduction of mineral acid solutions in inductively coupled plasma mass spectrometry (ICP-MS) was evaluated. Water, nitric acid, hydrochloric acid, perchloric acid and sulphuric acid in concentrations within the 0.05-1.0 mol l-1 range were studied. For all the acids tested, increasing the acid concentration increases the ion signal and deteriorates the precision. The magnitude of the signal enhancement depends on the analyte and on the acid considered. Acid solutions give rise to ion signals that are between 2 and 10 times higher than those with water. Among the acids tested, sulphuric acid provides the highest signals. The addition of palladium reduces matrix effects due to the acids and increases the signal in ETV ICP-MS. In comparison with conventional sample nebulization (CS), the ETV sample introduction system provides higher sensitivities (between 2 and 20 times higher) at the same acid concentration. The magnitude of this improvement is similar to that obtained with a microwave desolvation system (MWDS). The ETV sample introduction system gives rise to the lowest background signals from matrix-induced species. Due to this fact, the limits of detection (LODs) obtained for the isotopes affected by any interference are lower for ETV sample introduction than those obtained with the CS and the MWDS. For the isotopes that do not suffer from matrix-induced spectral interferences, the ETV gives rise to LODs higher than those obtained with the CS. For these isotopes the lowest LODs are obtained with MWDS.

SEPARATION OF RUTHENIUM FROM AQUEOUS SOLUTIONS

DOEpatents

Callis, C.F.; Moore, R.L.

1959-09-01

>The separation of ruthenium from aqueous solutions containing uranium plutonium, ruthenium, and fission products is described. The separation is accomplished by providing a nitric acid solution of plutonium, uranium, ruthenium, and fission products, oxidizing plutonium to the hexavalent state with sodium dichromate, contacting the solution with a water-immiscible organic solvent, such as hexone, to extract plutonyl, uranyl, ruthenium, and fission products, reducing with sodium ferrite the plutonyl in the solvent phase to trivalent plutonium, reextracting from the solvent phase the trivalent plutonium, ruthenium, and some fission products with an aqueous solution containing a salting out agent, introducing ozone into the aqueous acid solution to oxidize plutonium to the hexavalent state and ruthenium to ruthenium tetraoxide, and volatizing off the ruthenium tetraoxide.

A Smart Molecule for Selective Sensing of Nitric Oxide: Conversion of NO to HSNO; Relevance of Biological HSNO Formation.

PubMed

Islam, Abu Saleh Musha; Bhowmick, Rahul; Pal, Kaberi; Katarkar, Atul; Chaudhuri, Keya; Ali, Mahammad

2017-04-17

A smart molecule, QT 490 , containing thiosemicarbazide moiety acts as a highly selective turn-on in vitro NO sensor through the unprecedented NO-induced transformation of thiosemicarbazide moiety to 1,3,4-oxadiazole heterocycle with the concomitant release of HSNO, thereby eliminating any interference from various endogenous biomolecules including dehydroascorbic acid, ascorbic acid, etc. The kinetic studies of the reactions between QT 490 and NO provide a mechanistic insight into formation of HSNO/RSNO from the reaction between H 2 S/RSH and NO in the biological system. This novel probe is non-cytotoxic, cell permeable, water-soluble, and appropriate for intracellular cytoplasmic NO sensing with the possibilities of in vivo applications.

Use of extractive distillation to produce concentrated nitric acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, P.C.; Griffin, T.P.; Irwin, C.F.

1981-04-01

Concentrated nitric acid (> 95 wt %) is needed for the treatment of off-gases from a fuels-reprocessing plant. The production of concentrated nitric acid by means of extractive distillation in the two-pot apparatus was studied to determine the steady-state behavior of the system. Four parameters, EDP volume (V/sub EDP/) and temperature (T/sub EDP/), acid feed rate, and solvent recycle, were independently varied. The major response factors were percent recovery (CPRR) and product purity (CCP). Stage efficiencies also provided information about the system response. Correlations developed for the response parameters are: CPRR = 0.02(V/sub EDP/ - 800 cc) + 53.5; CCPmore » = -0.87 (T/sub EDP/ - 140/sup 0/C) + 81; eta/sub V,EDP/ = 9.1(F/sub feed/ - 11.5 cc/min) - 0.047(V/sub EDP/ - 800 cc) - 2.8(F/sub Mg(NO/sub 3/)/sub 2// - 50 cc/min) + 390; and eta/sub L,EDP/ = 1.9(T/sub EDP/ - 140/sup 0/C) + 79. A computer simulation of the process capable of predicting steady-state conditions was developed, but it requires further work.« less

Alpha radiolysis of nitric acid and sodium nitrate with 4He2+ beam of 13.5 MeV energy

NASA Astrophysics Data System (ADS)

Garaix, G.; Venault, L.; Costagliola, A.; Maurin, J.; Guigue, Mireille; Omnee, R.; Blain, G.; Vandenborre, J.; Fattahi, M.; Vigier, N.; Moisy, P.

2015-01-01

A study of aqueous nitric acid solution alpha radiolysis was performed through experiments carried out at a cyclotron facility, where a helion beam with an energy of 13.5 MeV could be delivered into the solution. The effects of nitrate and hydronium ions on the formation yields of hydrogen peroxide and nitrous acid, G(H2O2) and G(HNO2), were studied. The results showed that G(H2O2) decreases linearly with increasing nitrate ion concentration. On the other hand, G(HNO2) increases with the nitrate ion concentration until it reaches a plateau for nitric acid concentrations higher than 2 mol L-1. It was also found that an increase of hydronium ion concentration has a favorable effect on G(H2O2) and G(HNO2). Furthermore, it appears that these effects are additive and that the variations of G(H2O2) and G(HNO2) can be described by two parametric expressions, as a function of the nitrate and hydronium ion concentrations.

Modulation of parathion toxicity by glucose feeding: Is nitric oxide involved?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu Jing; Gupta, Ramesh C.; Goad, John T.

2007-03-15

Glucose feeding can markedly exacerbate the toxicity of the anticholinesterase insecticide, parathion. We determined the effects of parathion on brain nitric oxide and its possible role in potentiation of toxicity by glucose feeding. Adult rats were given water or 15% glucose in water for 3 days and challenged with vehicle or parathion (18 mg/kg, s.c.) on day 4. Functional signs, plasma glucose and brain cholinesterase, citrulline (an indicator of nitric oxide production) and high-energy phosphates (HEPs) were measured 1-3 days after parathion. Glucose feeding exacerbated cholinergic toxicity. Parathion increased plasma glucose (15-33%) and decreased cortical cholinesterase activity (81-90%), with nomore » significant differences between water and glucose treatment groups. In contrast, parathion increased brain regional citrulline (40-47%) and decreased HEPs (18-40%) in rats drinking water, with significantly greater changes in glucose-fed rats (248-363% increase and 31-61% decrease, respectively). We then studied the effects of inhibiting neuronal nitric oxide synthase (nNOS) by 7-nitroindazole (7NI, 30 mg/kg, i.p. x4) on parathion toxicity and its modulation by glucose feeding. Co-exposure to parathion and 7NI led to a marked increase in cholinergic signs of toxicity and lethality, regardless of glucose intake. Thus, glucose feeding enhanced the accumulation of brain nitric oxide following parathion exposure, but inhibition of nitric oxide synthesis was ineffective at counteracting increased parathion toxicity associated with glucose feeding. Evidence is therefore presented to suggest that nitric oxide may play both toxic and protective roles in cholinergic toxicity, and its precise contribution to modulation by glucose feeding requires further investigation.« less

Interim glycol flowsheet reduction/oxidation (redox) model for the Defense Waste Processing Facility (DWPF)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C. M.; Williams, M. S.; Zamecnik, J. R.

Control of the REDuction/OXidation (REDOX) state of glasses containing high concentrations of transition metals, such as High Level Waste (HLW) glasses, is critical in order to eliminate processing difficulties caused by overly reduced or overly oxidized melts. Operation of a HLW melter at Fe +2/ΣFe ratios of between 0.09 and 0.33, a range which is not overly oxidizing or overly reducing, helps retain radionuclides in the melt, i.e. long-lived radioactive 99Tc species in the less volatile reduced Tc 4+ state, 104Ru in the melt as reduced Ru +4 state as insoluble RuO 2, and hazardous volatile Cr 6+ in themore » less soluble and less volatile Cr +3 state in the glass. The melter REDOX control balances the oxidants and reductants from the feed and from processing additives such as antifoam. Currently, the Defense Waste Processing Facility (DWPF) is running a formic acid-nitric acid (FN) flowsheet where formic acid is the main reductant and nitric acid is the main oxidant. During decomposition formate and formic acid releases H 2 gas which requires close control of the melter vapor space flammability. A switch to a nitric acid-glycolic acid (GN) flowsheet is desired as the glycolic acid flowsheet releases considerably less H 2 gas upon decomposition. This would greatly simplify DWPF processing. Development of an EE term for glycolic acid in the GN flowsheet is documented in this study.« less

Simple quantification of surface carboxylic acids on chemically oxidized multi-walled carbon nanotubes

NASA Astrophysics Data System (ADS)

Gong, Hyejin; Kim, Seong-Taek; Lee, Jong Doo; Yim, Sanggyu

2013-02-01

The surface of multi-walled carbon nanotube (MWCNT) was chemically oxidized using nitric acid and sulfuric-nitric acid mixtures. Thermogravimetric analysis, transmission electron microscopy and infrared spectroscopy revealed that the use of acid mixtures led to higher degree of oxidation. More quantitative identification of surface carboxylic acids was carried out using X-ray photoelectron spectroscopy (XPS) and acid-base titration. However, these techniques are costly and require very long analysis times to promptly respond to the extent of the reaction. We propose a much simpler method using pH measurements and pre-determined pKa value in order to estimate the concentration of carboxylic acids on the oxidized MWCNT surfaces. The results from this technique were consistent with those obtained from XPS and titration, and it is expected that this simple quantification method can provide a cheap and fast way to monitor and control the oxidation reaction of MWCNT.

Synthesis and biological evaluation of amino acid methyl ester conjugates of 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oic acid against the production of nitric oxide (NO).

PubMed

Onyango, Evans O; Fu, Liangfeng; Cao, Martine; Liby, Karen T; Sporn, Michael B; Gribble, Gordon W

2014-01-15

2-Cyano-3,12-dioxooleana-1,9(11)-dien-28-oic acid (CDDO, 2) was condensed with various amino acid methyl esters at the C-28 carboxylic acid. The new amide conjugates were evaluated for their inhibition of nitric oxide (NO) production in RAW264.7 cells stimulated with interferon-γ (IFNγ). Of these new compounds, CDDO conjugates with alanine, valine, and serine are nearly equipotent to CDDO-ethyl amide (4), a triterpenoid with promising biological activity in numerous disease models. Some of these conjugates also induce the in vitro expression of heme oxygenase-1, and inhibit the proliferation of Panc-1343 pancreatic cells. Copyright © 2013 Elsevier Ltd. All rights reserved.

Studies on the oxidation of hexamethylbenzene 2: Preparation of dimethylpyromellitic acid

NASA Technical Reports Server (NTRS)

Chiba, K.; Tomura, S.

1986-01-01

Hexamethylbenzene (HMB) was difficult to be oxidized with an alkaline potassium permanganate solution, since HMB was insoluble in an aqueous alkaline solution. But, when HMB was warmed with 50% nitric acid for a short time, and then treated with aqueous potassium permanganate, the reaction occurred readily and dimethylpyromellitic acid was obtained. When HMB was warmed with 50% nitric acid for 1 to 2 minutes, a yellow material was produced, which was soluble in hot aqueous potassium hydroxide, though free from carboxylic acids. It contained a little amount of bis-(nitromethyl)prehnitene and several unknown compounds. Further, the heat stability of polyimide prepared by the reaction of tetramethyldimethylpyromellitate with 4,4 prime-diaminodiphenylmethane turned out to be nearly equal to that of polyimide prepared from tetramethylpyromellitate.

Purification of uranium alloys by differential solubility of oxides and production of purified fuel precursors

DOEpatents

McLean, II, William; Miller, Philip E.

1997-01-01

A method for purifying metallic alloys of uranium for use as nuclear reactor fuels in which the metal alloy is first converted to an oxide and then dissolved in nitric acid. Initial removal of metal oxide impurities not soluble in nitric acid is accomplished by filtration or other physical means. Further purification can be accomplished by carbonate leaching of uranyl ions from the partially purified solution or using traditional methods such as solvent extraction.

Purification of uranium alloys by differential solubility of oxides and production of purified fuel precursors

DOEpatents

McLean, W. II; Miller, P.E.

1997-12-16

A method is described for purifying metallic alloys of uranium for use as nuclear reactor fuels in which the metal alloy is first converted to an oxide and then dissolved in nitric acid. Initial removal of metal oxide impurities not soluble in nitric acid is accomplished by filtration or other physical means. Further purification can be accomplished by carbonate leaching of uranyl ions from the partially purified solution or using traditional methods such as solvent extraction. 3 figs.

METHOD OF CLEANING METAL SURFACES

DOEpatents

Winkler, H.W.; Morfitt, J.W.; Little, T.H.

1959-05-19

Cleaning fluids for removing deposits from metal surfaces are described. The cleaning agents of the invention consist of aqueous nitric acid and an amhydrous nitrate salt of a metal which is lower in the electromotive series than the element of the deposit to be removed. In general, the salt content of thc cleaning agents ranged from 10 to 90%, preferably from 10 to 40% by weight; and the balance of the composition comprises nitric acid of any strength from extremely dilute up to concentrated strength.

Nitric Oxide Generating Polymeric Coatings for Subcutaneous Glucose Sensors

DTIC Science & Technology

2007-10-01

primary polymer which was then aminated (2) for attachment of (Boc)3-cyclen-N-acetic acid (1). After the conjugation via EDC coupling chemistry, the Boc...dipping procedure is repeated 5 times. This is the needle-type NO sensor currently used (e.g., Figure 4 device but w/o the SePEI and alginic acid ...Cha, M. E. Meyerhoff, " Polymethacrylates with Covalently Linked Cu(II)-Cyclen Complex for the In-Situ Generation of Nitric Oxide from Nitrosothiols in

Hazards Analysis of Holston Ammonium Nitrate/Nitric Acid Storage and Transfer System

DTIC Science & Technology

1974-07-01

amonium nitrate re- sulting from an abnormally hbigh heat input which goes uncorrected. A 111-4 failure in either type of heating line has the potential...34 WC P.O. 080-0265, ABL FinM~l Report, November 1971. 14. C. Feick and R. Iiraies, *On the Thermal Decomposition of Amonium Nitrate Steady-State...AD-AO22 868 HAZARDS ANALYSIS OF HOLSTON AMMONIUM NITRATE /NITRIC ACID STORAGE AND TRANSFER SYSTEM W. L. Walker Hercules, Incorporated Prepared for

RECOVERY OF URANIUM FROM ZIRCONIUM-URANIUM NUCLEAR FUELS

DOEpatents

Gens, T.A.

1962-07-10

An improvement was made in a process of recovering uranium from a uranium-zirconium composition which was hydrochlorinated with gsseous hydrogen chloride at a temperature of from 350 to 800 deg C resulting in volatilization of the zirconium, as zirconium tetrachloride, and the formation of a uranium containing nitric acid insoluble residue. The improvement consists of reacting the nitric acid insoluble hydrochlorination residue with gaseous carbon tetrachloride at a temperature in the range 550 to 600 deg C, and thereafter recovering the resulting uranium chloride vapors. (AEC)

Differential effects of ABT-510 and a CD36-binding peptide derived from the type 1 repeats of thrombospondin-1 on fatty acid uptake, nitric oxide signaling, and caspase activation in vascular cells.

PubMed

Isenberg, Jeff S; Yu, Christine; Roberts, David D

2008-02-15

ABT-510 is a potent mimetic of an anti-angiogenic sequence from the second type 1 repeat of thrombospondin-1. ABT-510 and the original d-Ile mimetic from which it was derived, GDGV(dI)TRIR, are similarly active for inhibiting vascular outgrowth in a B16 melanoma explant assay. Because GDGV(dI)TRIR and thrombospondin-1 modulate nitric oxide signaling by inhibiting the fatty translocase activity of CD36, we examined the ability ABT-510 to modulate fatty acid uptake into vascular cells and downstream nitric oxide/cGMP signaling. Remarkably, ABT-510 is less active than GDGV(dI)TRIR for inhibiting myristic acid uptake into both endothelial and vascular smooth muscle cells. Correspondingly, ABT-510 is less potent than GDGV(dI)TRIR for blocking a myristate-stimulated increase in cell adhesion to collagen and nitric oxide-driven accumulation of cGMP. ABT-510 at concentrations sufficient to inhibit CD36 fatty acid translocase activity synergizes with thrombin in aggregating platelets and blunts the activity of NO to delay aggregation, but again less than GDGV(dI)TRIR. In contrast, ABT-510 is more potent than GDGV(dI)TRIR for inducing caspase activation in vascular cells. Thus, we propose that ABT-510 is a drug with at least two mechanisms of action, and its potent anti-tumor activity may be in part independent of CD36 fatty acid translocase inhibition.

Differential Effects of ABT-510 and a CD36-binding Peptide Derived from the Type 1 Repeats of Thrombospondin-1 on Fatty Acid Uptake, Nitric Oxide Signaling, and Caspase Activation in Vascular Cells

PubMed Central

Isenberg, Jeff S.; Yu, Christine; Roberts, David D.

2008-01-01

ABT-510 is a potent mimetic of an anti-angiogenic sequence from the second type 1 repeat of thrombospondin-1. ABT-510 and the original d-Ile mimetic from which it was derived, GDGV(dI)TRIR, are similarly active for inhibiting vascular outgrowth in a B16 melanoma explant assay. Because GDGV(dI)TRIR and thrombospondin-1 modulate nitric oxide signaling by inhibiting the fatty translocase activity of CD36, we examined the ability ABT-510 to modulate fatty acid uptake into vascular cells and downstream nitric oxide/cGMP signaling. Remarkably, ABT-510 is less active than GDGV(dI)TRIR for inhibiting myristic acid uptake into both endothelial and vascular smooth muscle cells. Correspondingly, ABT-510 is less potent than GDGV(dI)TRIR for blocking a myristate-stimulated increase in cell adhesion to collagen and nitric oxide-driven accumulation of cGMP. ABT-510 at concentrations sufficient to inhibit CD36 fatty acid translocase activity synergizes with thrombin in aggregating platelets and blunts the activity of NO to delay aggregation, but again less than GDGV(dI)TRIR. In contrast, ABT-510 is more potent than GDGV(dI)TRIR for inducing caspase activation in vascular cells. Thus, we propose that ABT-510 is a drug with at least two mechanisms of action, and its potent anti-tumor activity may be in part independent of CD36 fatty acid translocase inhibition. PMID:18068687

Mechanisms of neptunium redox reactions in nitric acid solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chatterjee, Sayandev; Bryan, Samuel A.; Casella, Amanda J.

First transuranium element neptunium (Np) exhibits complicated behavior in acidic solutions because it can adopt wide range of oxidation states typically from +3 to +6 and coordinate large variety of ligands. In particular, accurate determination of Np redox potentials in nitric acid solutions is challenging due to overlapping chemical and electrochemical reactions leading to significant experimental uncertainties. Furthermore, over past decades spectrophotometry has been extensively applied to identify and characterize Np solution species in different oxidation states. However, relevant spectral database of Np in nitric acid solutions that can serve for the reference purposes has yet to be established duemore » to the experimental difficulty to isolate and stabilize Np species in pure oxidation states without compromising solution optical properties. This work demonstrates that combination of voltammetry and controlled-potential in situ thin-layer spectropotentiometry overcomes these challenges so that Np species in pure +3, +4, +5, or +6 oxidation states were electrochemically generated in the systematically varied 0.1 – 5 M nitric acid solutions, and corresponding vis-NIR spectral signatures were obtained. In situ optical monitoring of the interconversion between adjacent Np oxidation states resulted in elucidation of the mechanisms of the involved redox reactions, in-depth understanding of the relative stability of the Np oxidation states, and allowed benchmarking of the redox potentials of the NpO22+/NpO2+, NpO2+/Np4+ and Np4+/Np3+ couples. Notably, the NpO2+/Np4+ couple was distinguished from the proximal Np4+/Np3+ process overcoming previous concerns and challenges encountered in accurate determination of the respective potentials.« less

Corrosion Testing of Monofrax K-3 Refractory in Defense Waste Processing Facility (DWPF) Alternate Reductant Feeds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, M.; Jantzen, C.; Burket, P.

The Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS) uses a combination of reductants and oxidants while converting high level waste (HLW) to a borosilicate waste form. A reducing flowsheet is maintained to retain radionuclides in their reduced oxidation states which promotes their incorporation into borosilicate glass. For the last 20 years of processing, the DWPF has used formic acid as the main reductant and nitric acid as the main oxidant. During reaction in the Chemical Process Cell (CPC), formate and formic acid release measurably significant H 2 gas which requires monitoring of certain vessel’s vapor spaces.more » A switch to a nitric acid-glycolic acid (NG) flowsheet from the nitric-formic (NF) flowsheet is desired as the NG flowsheet releases considerably less H 2 gas upon decomposition. This would greatly simplify DWPF processing from a safety standpoint as close monitoring of the H 2 gas concentration could become less critical. In terms of the waste glass melter vapor space flammability, the switch from the NF flowsheet to the NG flowsheet showed a reduction of H 2 gas production from the vitrification process as well. Due to the positive impact of the switch to glycolic acid determined on the flammability issues, evaluation of the other impacts of glycolic acid on the facility must be examined.« less

Determination of diphenylarsinic acid, phenylarsonic acid and inorganic arsenic in drinking water by graphite-furnace atomic-absorption spectrometry after simultaneous separation and preconcentration with solid-phase extraction disks.

PubMed

Hagiwara, Kenta; Inui, Tetsuo; Koike, Yuya; Nakamura, Toshihiro

2013-01-01

A simple method of graphite-furnace atomic-absorption spectrometry (GFAAS) after solid-phase extraction (SPE) was developed for the determination of diphenylarsinic acid (DPAA), phenylarsonic acid (PAA), and inorganic arsenic (iAs) in drinking water. This method involves the simultaneous collection of DPAA, PAA, and iAs using three stacked SPE disks, i.e., an Empore SDB-XD disk (the upper layer), an activated carbon disk (the middle layer), and a Cation-SR disk loaded with Zr and Ca (ZrCa-CED; the lower layer). A 200-mL aqueous sample was adjusted to pH 3 with nitric acid and passed through the SPE disks at a flow rate of 15 mL min(-1), to concentrate DPAA on the SDB-XD disk, PAA on the activated carbon disk, and iAs on the ZrCa-CED. The As compounds were eluted from the disks with 10 mL of ethanol containing 0.5 mol L(-1) ammonia solution for DPAA, 20 mL of 1 mol L(-1) ammonia solution for PAA, and 20 mL of 6 mol L(-1) hydrochloric acid for iAs. The eluates of DPAA, PAA, and iAs were diluted to 20, 25, and 25 mL, respectively, with deionized water, and then analyzed by GFAAS. The detection limits of As (three-times the standard deviation (n = 3) of the blank values) were 0.13 and 0.16 μg L(-1) at enrichment factors of 10 and 8, respectively, using a 200-mL water sample. Spike tests with 2 μg (10 μg L(-1)) of DPAA, PAA, and iAs in 200 mL of tap water and bottled drinking water showed good recoveries (96.1-103.8%).

Effects of polymorphisms in endothelial nitric oxide synthase and folate metabolizing genes on the concentration of serum nitrate, folate, and plasma total homocysteine after folic acid supplementation: a double-blind crossover study.

PubMed

Cabo, Rona; Hernes, Sigrunn; Slettan, Audun; Haugen, Margaretha; Ye, Shu; Blomhoff, Rune; Mansoor, M Azam

2015-02-01

A number of studies have explored the effects of dietary nitrate on human health. Nitrate in the blood can be recycled to nitric oxide, which is an essential mediator involved in many important biochemical mechanisms. Nitric oxide is also formed in the body from l-arginine by nitric oxide synthase. The aim of this study was to investigate whether genetic polymorphisms in endothelial nitric oxide synthase (eNOS) and genes involved in folate metabolism affect the concentration of serum nitrate, serum folate, and plasma total homocysteine in healthy individuals after folic acid supplementation. In a randomized double-blind, crossover study, participants were given either folic acid 800 μg/d (n = 52) or placebo (n = 51) for 2 wk. Wash-out period was 2 wk. Fasting blood samples were collected, DNA was extracted by salting-out method and the polymorphisms in eNOS synthase and folate genes were genotyped by polymerase chain reaction methods. Measurement of serum nitrate and plasma total homocysteine (p-tHcy) concentration was done by high-performance liquid chromatography. The concentration of serum nitrate did not change in individuals after folic acid supplements (trial 1); however, the concentration of serum nitrate increased in the same individuals after placebo (P = 0.01) (trial 2). The individuals with three polymorphisms in eNOS gene had increased concentration of serum folate and decreased concentration of p-tHcy after folic acid supplementation. Among the seven polymorphisms tested in folate metabolizing genes, serum nitrate concentration was significantly decreased only in DHFR del 19 gene variant. A significant difference in the concentration of serum nitrate was detected among individuals with MTHFR C > T677 polymorphisms. Polymorphisms in eNOS and folate genes affect the concentration of serum folate and p-tHcy but do not have any effect on the concentration of NO3 in healthy individuals after folic acid supplementation. Copyright © 2015 Elsevier Inc. All rights reserved.

Reference electrode for strong oxidizing acid solutions

DOEpatents

Rigdon, Lester P.; Harrar, Jackson E.; Bullock, Sr., Jack C.; McGuire, Raymond R.

1990-01-01

A reference electrode for the measurement of the oxidation-reduction potentials of solutions is especially suitable for oxidizing solutions such as highly concentrated and fuming nitric acids, the solutions of nitrogen oxides, N.sub.2 O.sub.4 and N.sub.2 O.sub.5, in nitric acids. The reference electrode is fabricated of entirely inert materials, has a half cell of Pt/Ce(IV)/Ce(III)/70 wt. % HNO.sub.3, and includes a double-junction design with an intermediate solution of 70 wt. % HNO.sub.3. The liquid junctions are made from Corning No. 7930 glass for low resistance and negligible solution leakage.

Determination of Natural and Depleted Uranium in Urine at the ppt Level: An Interlaboratory Analytical Exercise

DTIC Science & Technology

2002-10-01

but de cet exercice analytique 6tait d𔄀valuer toutes les techniques analytiques disponibles ayant la capacit6 de mesurer les rapports isotopiques...B Formulation. Step Component Amount added 1 2% v/v nitric acid 500 mL 2 Calcium chloride (CaCl2.2H 20) 12.6 g 3 2% v/v nitric acid Dilute to 1000 mL...chloride (KCI) 3.43 Sodium chloride (NaCl) 2.32 Creatinine (C4H7N30) 1.10 Ammonium chloride (NH 4Cl) 1.06 Hippuric acid (C9H9N03) 0.63 Calcium chloride

Analysis of trace metals in water by inductively coupled plasma emission spectrometry using sodium dibenzyldithiocarbamate for preconcentration

USGS Publications Warehouse

Smith, C.L.; Motooka, J.M.; Willson, W.R.

1984-01-01

Since concentrations of trace elements in most natural waters seldom exceed the ??g/L level, analysis of trace elements in natural waters by inductively coupled plasma emission spectrometry (ICP) requires a preconcentration procedure. The elements Ag, Bi, Cd, Co, Cu, Fe, Mo, Ni, Pb, Sn, V, W, and Zn were separated and concentrated from 500 mL of water by coprecipitating them with sodium dibenzyldithiocarbamate (NaDBDTC) using nickel or silver as a carrier. The precipitated trace elements were collected on a membrane filter, redissolved from the filter with hot nitric and hydrochloric acids, and analyzed using ICP. Recoveries for all the trace elements except tungsten exceeded 80%. Coprecipitation of trace elements with NaDBDTC eliminated the use of difficult-to-inject organic solvents, and NaDBDTC coprecipitated a wider array of trace elements than ammoniumpyrrolidinedithiocarbamate (APDC), another commonly used coprecipitate.

Optimisation of the storage of natural freshwaters before organotin speciation.

PubMed

Bancon-Montigny, C; Lespes, G; Potin-Gautier, M

2001-01-01

The speciation of organotin compounds is essential due to the species-dependent toxicity, especially in natural waters. Precautions have to be taken during sampling and storage of waters in order to prevent degradations and losses. Experimental design methodology has been used to study the conditions of stability of organotins after water sampling in rivers. The modelling of results allows the determination of optimal conditions of preservation. After acidification at pH = 4 with nitric acid, the storage in polyethylene containers at 4 degrees C in the dark is suitable to preserve the most degradable trisubstituted (butyl- and phenyl-) species over 1 month. These conditions of sampling and storage are applied to two different freshwaters. The rate of species decomposition appears to be only dependent on the water nature, whatever the organotin concentrations in the sample. Speciation could be so preserved between 1 and 3 months.

Optimization of HNO3 leaching of copper from old AMD Athlon processors using response surface methodology.

PubMed

Javed, Umair; Farooq, Robina; Shehzad, Farrukh; Khan, Zakir

2018-04-01

The present study investigates the optimization of HNO 3 leaching of Cu from old AMD Athlon processors under the effect of nitric acid concentration (%), temperature (°C) and ultrasonic power (W). The optimization study is carried out using response surface methodology with central composite rotatable design (CCRD). The ANOVA study concludes that the second degree polynomial model is fitted well to the fifteen experimental runs based on p-value (0.003), R 2 (0.97) and Adj-R 2 (0.914). The study shows that the temperature is the most significant process variable to the leaching concentration of Cu followed by nitric acid concentration. However, ultrasound power shows no significant impact on the leaching concentration. The optimum conditions were found to be 20% nitric acid concentration, 48.89 °C temperature and 5.52 W ultrasound power for attaining maximum concentration of 97.916 mg/l for Cu leaching in solution. Copyright © 2018 Elsevier Ltd. All rights reserved.

Condensed-Phase Nitric Acid in a Tropical Subvisible Cirrus Cloud

NASA Technical Reports Server (NTRS)

Popp, P. J.; Marcy, T. P.; Watts, O. A.; Gao, R. S.; Fahey, D. W.; Weinstock, E. M.; Smith, J. B.; Herman, R. L.; Tropy, R. F.; Webster, C. r.;

System for recovery of daughter isotopes from a source material

DOEpatents

Tranter, Troy J [Idaho Falls, ID; Todd, Terry A [Aberdeen, ID; Lewis, Leroy C [Idaho Falls, ID; Henscheid, Joseph P [Idaho Falls, ID

2009-08-04

A method of separating isotopes from a mixture containing at least two isotopes in a solution is disclosed. A first isotope is precipitated and is collected from the solution. A daughter isotope is generated and collected from the first isotope. The invention includes a method of producing an actinium-225/bismuth-213 product from a material containing thorium-229 and thorium-232. A solution is formed containing nitric acid and the material containing thorium-229 and thorium-232, and iodate is added to form a thorium iodate precipitate. A supernatant is separated from the thorium iodate precipitate and a second volume of nitric acid is added to the thorium iodate precipitate. The thorium iodate precipitate is stored and a decay product comprising actinium-225 and bismuth-213 is generated in the second volume of nitric acid, which is then separated from the thorium iodate precipitate, filtered, and treated using at least one chromatographic procedure. A system for producing an actinium-225/bismuth-213 product is also disclosed.

Effect of Three-spot Seahorse Petroleum Ether Extract on Lipopolysaccharide Induced Macrophage RAW264.7 Inflammatory Cytokine Nitric Oxide and Composition Analysis.

PubMed

Chen, LiPing; Shen, XuanRi; Chen, GuoHua; Cao, XianYing; Yang, Jian

2015-01-01

Three-Spot seahorse is a traditional medicine in Asian countries. However, the alcohol extract is largely unknown for its anti-inflammatory activity. This study aimed at elucidating fraction of potent anti-inflammatory activity of seahorse. A systematic solvent extraction method of liquid-liquid fractionation of ethanol crude extract gave four fractions petroleum ether (PE), and ethyl acetate (EtOAc), water saturated butanol (n-BuOH), water (H2O). In this study, PE extract was selected for further study after preliminary screening test, and was connected to silica column chromatography and eluted with different polarity of mobile phases, and obtained four active fractions (Fr I, Fr II, Fr III, Fr IV). Effect of separated fractions on inflammation was investigated in lipopolysaccharide (LPS) stimulated murine RAW264.7 cells in vitro. The result shows that seahorse extract was capable of inhibiting the production of nitric oxide (NO) significantly in a dose dependent manner and exhibited no notable cytotoxicity on cell viability. IC50 of fraction IV was 36.31 μg/mL, indicating that separated fraction possessed potent NO inhibitory activity against LPS-induced inflammatory response, thus, demonstrated its in vitro anti-inflammatory potentiality, it may be at least partially explained by the presence of anti-inflammation active substances, phenolic compounds, phospholipids and polyunsaturated fatty acids, especially phospholipids and polyunsaturated fatty acids. It could be suggested that seahorse lipid-soluble components could be used in functional food and anti-inflammatory drug preparations.

Evaluation of Antioxidant Activity of Tetracarpidium conophorum (Müll. Arg) Hutch & Dalziel Leaves

PubMed Central

Amaeze, O. U.; Ayoola, G. A.; Sofidiya, M. O.; Adepoju-Bello, A. A.; Adegoke, A. O.; Coker, H. A. B.

2011-01-01

This study evaluated the antioxidant activity as well as bioflavonoid content of the methanol and ethanol-water extracts of the fresh and dried leaves of Tetracarpidium conophorum. Antioxidant activity was determined by spectrophotometric methods using DPPH free radical, nitric oxide radical inhibition and ferric reducing antioxidant power assays. In addition, total phenolics, flavonoids and proanthocyanidin content were also determined. The ethanol: water extract of the dried leaves had the highest antioxidant activity with a 50% inhibition of DPPH at a concentration of 0.017 mg/mL compared to the standards, Vitamin C and Vitamin E with inhibition of 0.019 and 0.011 mg/mL, respectively. This extract also showed nitric oxide radical inhibition activity comparable to that of rutin, 54.45% and 55.03% for extract and rutin, respectively, at 0.1 mg/mL. Ferric reducing power was also comparable to that of ascorbic acid (281 and 287 μM Fe (11)/g, resp.) at a concentration of 1 mg/mL. The methanol extract of both the dried and the fresh leaves had higher phenolic, flavonoids and proanthocyanidin content than the ethanol : water extract. The study reveals that T. conophorum can be an interesting source of antioxidants with their potential use in different fields namely food, cosmetics and pharmaceuticals. PMID:21912723

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adib, F.; Bagreev, A.; Bandosz, T.J.

The H{sub 2}S breakthrough capacity was measured on two series of activated carbons of a coconut shell and a bituminous coal origins. To broaden the spectrum of surface features the samples were oxidized using nitric acid or ammonium persulfate under conditions chosen to preserve their pore structures. Then the carbons were characterized using Boehm titration, potentiometric titration, thermal analysis, temperature programmed desorption, sorption of nitrogen, and sorption of water. It was found that the choice of unimpregnated carbon for application as H{sub 2}S adsorbent should be made based on parameters of its acidity such as number of acidic groups, pHmore » of surface, amount of surface groups oxygen, or weight loss associated to decomposition of surface oxygen species. The results obtained from the analyses of six unimpregnated carbon samples suggest that there are certain threshold values of these quantities which, when exceeded, have a dramatic effect on the H{sub 2}S breakthrough capacity.« less

Determination of Silicon in Hydrazine

NASA Technical Reports Server (NTRS)

McClure, Mark B.; Mast, Dion; Greene, Ben; Maes, Miguel J.

2006-01-01

Inductively coupled plasma-mass spectrometry (ICP-MS) is a highly sensitive technique sometimes used for the trace determination of silicon at a mass-to-charge (m/z) ratio of 28, the most abundant natural isotope of silicon. Unfortunately, ICP-MS is unable to differentiate between other sources of m/z 28 and false positive results for silicon will result when other sources of m/z 28 are present. Nitrogen was a major source of m/z 28 and contributes to the m/z 28 signal when hydrazine sample or nitric acid preservative is introduced into the plasma. Accordingly, this work was performed to develop a sample preparation step coupled with an ICP-MS analysis that minimized non-silicon sources of m/z 28. In the preparatory step of this method, the hydrazine sample was first decomposed predominately to nitrogen gas and water with copper-catalyzed hydrogen peroxide. In the analysis step, ICP-MS was used without nitric acid preservative in samples or standards. Glass, a potential source of silicon contamination, was also avoided where possible. The method was sensitive, accurate, and reliable for the determination of silicon in monopropellant grade hydrazine (MPH) in AF-E-332 elastomer leaching tests. Results for silicon in MPH were comparable to those reported in the literature for other studies.

Partial microwave-assisted wet digestion of animal tissue using a baby-bottle sterilizer for analyte determination by inductively coupled plasma optical emission spectrometry

NASA Astrophysics Data System (ADS)

Matos, Wladiana O.; Menezes, Eveline A.; Gonzalez, Mário H.; Costa, Letícia M.; Trevizan, Lilian C.; Nogueira, Ana Rita A.

2009-06-01

A procedure for partial digestion of bovine tissue is proposed using polytetrafluoroethylene (PTFE) micro-vessels inside a baby-bottle sterilizer under microwave radiation for multi-element determination by inductively coupled plasma optical emission spectrometry (ICP OES). Samples were directly weighed in laboratory-made polytetrafluoroethylene vessels. Nitric acid and hydrogen peroxide were added to the uncovered vessels, which were positioned inside the baby-bottle sterilizer, containing 500 mL of water. The hydrogen peroxide volume was fixed at 100 µL. The system was placed in a domestic microwave oven and partial digestion was carried out for the determination of Ca, Cu, Fe, Mg, Mn and Zn by inductively coupled plasma optical emission spectrometry. The single-vessel approach was used in the entire procedure, to minimize contamination in trace analysis. Better recoveries and lower residual carbon content (RCC) levels were obtained under the conditions established through a 2 4-1 fractional factorial design: 650 W microwave power, 7 min digestion time, 50 µL nitric acid and 50 mg sample mass. The digestion efficiency was ascertained according to the residual carbon content determined by inductively coupled plasma optical emission spectrometry. The accuracy of the proposed procedure was checked against two certified reference materials.

Neutral endopeptidase knockout induces hyperalgesia in a model of visceral pain, an effect related to bradykinin and nitric oxide.

PubMed

Fischer, Hanspeter S; Zernig, Gerald; Hauser, Kurt F; Gerard, Craig; Hersh, Louis B; Saria, Alois

2002-01-01

Neutral endopeptidase (EC3.4.24.11, NEP, enkephalinase) is a zinc-metalloendopeptidase, cleaving a variety of substrates like enkephalins, substance P, and bradykinin. In the brain, NEP is a key enzyme in the degradation of enkephalins. Pharmacological inhibition of NEP-activity causes analgesia resulting from enhanced extracellular enkephalin concentrations. Recently, transgenic mice lacking the enzyme NEP have been developed (Lu, 1995). The present study was designed to investigate the nociceptive behavior of these NEP-knockout mice. Interestingly, NEP-deficient mice did not respond with decreased pain perception, but exhibited hyperalgesia in the hot-plate jump, warm-water tail-withdrawal, and mostnotablyin theacetic-acid writhing test. Inhibition of aminopeptidase N by bestatin reduced writhing in both strains, whereas NEP-inhibition by thiorphan reduced writhing selectively in wild-type mice. Naloxone increased writhing in wild-type but not in knockouts, whereas the bradykinin B2-receptor antagonist HOE140 reduced writhing selectively in NEP-knockouts. Similarly, the nitric oxide synthase inhibitor L-NAME reduced writhing in NEP-knockouts. These results indicate that genetic elimination of NEP, in contrast to pharmacological inhibition, leads to bradykinin-induced hyperalgesia instead of enkephalin-mediated analgesia. Nitric oxide (NO) is suggested to be involved in this process.

Etchant for incoloy-903 welds

NASA Technical Reports Server (NTRS)

Gerstmeyer, J. A.

1980-01-01

Special reagent consists of 1 part 90% lactic acid, 1 part 70% nitric acid, and 4 part, 37% hydrochloric acid. Solution etches parent and weld metals at same rate, without overetching. Underlying grain structure of both metals is revealed.

SOLVENT EXTRACTION PROCESS

DOEpatents

Jonke, A.A.

1957-10-01

In improved solvent extraction process is described for the extraction of metal values from highly dilute aqueous solutions. The process comprises contacting an aqueous solution with an organic substantially water-immiscible solvent, whereby metal values are taken up by a solvent extract phase; scrubbing the solvent extract phase with an aqueous scrubbing solution; separating an aqueous solution from the scrubbed solvent extract phase; and contacting the scrubbed solvent phase with an aqueous medium whereby the extracted metal values are removed from the solvent phase and taken up by said medium to form a strip solution containing said metal values, the aqueous scrubbing solution being a mixture of strip solution and an aqueous solution which contains mineral acids anions and is free of the metal values. The process is particularly effective for purifying uranium, where one starts with impure aqueous uranyl nitrate, extracts with tributyl phosphate dissolved in carbon tetrachloride, scrubs with aqueous nitric acid and employs water to strip the uranium from the scrubbed organic phase.

Study of the Tributyl Phosphate--30 Percent Dodecane Solvent; ETUDE DU SOLVANT PHOSPHATE TRIBUTYLIQUE 30 PERCENT--DODECANE (in French)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leroy, P.

1967-07-01

This study, originating mainly from a literature survey, gives the principal chemical and physical features of the tributyl-phosphate (TBP) agent diluted at 30 volumes per cent in dodecane. The mixture is a very commonly used extractant in nuclear fuel processing. In this paper, the main following points are reported: -) the components (TBP and diluents) -) the TBP-diluents systems (non-loaded), -) the TBP-diluents-water systems, -) TBP-diluents-water-nitric acid systems, and -) industrial solvents. (author) [French] Cette etude, d'origine bibliographique, regroupe les caracteristiques physico-chimiques essentielles du phosphate tributylique (TBP) dilue a 30% en volume dans du dodecane. Ce melange constitue un agentmore » d'extraction tres utilise dans le traitement des combustibles nucleaires. Les principaux points traites sont les suivants: -) les constituants (TBP et diluants), -) les systemes TBP-diluants non charges, -) les systemes TBP-diluants-eau, -) les systemes TBP-diluants-eau-acide nitrique, et -) les solvants industriels. (auteur)« less

Study to find the best extraction solvent for use with guava leaves (Psidium guajava L.) for high antioxidant efficacy.

PubMed

Seo, Jongkwon; Lee, Soojung; Elam, Marcus L; Johnson, Sarah A; Kang, Jonghoon; Arjmandi, Bahram H

2014-03-01

The effects of guava leaves extracted using solvents of water, ethanol, methanol, and different concentrations of hydroethanolic solvents on phenolic compounds and flavonoids, and antioxidant properties have been investigated. The antioxidant capability was assessed based on 2,2-diphenyl-1-picrylhydrazyl radical and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical-scavenging abilities, reducing power, and nitric oxide-and nitrate-scavenging activities. The results demonstrated that the antioxidant ability of guava leaf extracts has a strong relationship with phenolic compound content rather than flavonoid content. Phenolic compound content of water extracted guava leaves was higher compared to pure ethanol and methanol extracts. However, phenolic compound content extracted using hydroethanolic solvent was higher than water, whereas 50% hydroethanolic was observed to be the most effective solvent showing high antioxidant ability.

Effect of caffeine coadministration and of nitric oxide synthesis inhibition on the antinociceptive action of ketorolac.

PubMed

López-Muñoz, F J; Castañeda-Hernández, G; Flores-Murrieta, F J; Granados-Soto, V

1996-07-25

The effects of caffeine and nitric oxide synthesis inhibition on the antinociceptive action of ketorolac were assessed using the pain-induced functional impairment model in the rat. Nociception was induced by the intra-articular injection of uric acid. Ketorolac, but not caffeine, produced an antinociceptive effect which was reduced by NG nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthesis. Caffeine coadministration potentiated the ketorolac effect. L-NAME induced a dose-dependent reduction of this potentiation. The results suggest the participation of the L-arginine-nitric oxide-cyclic GMP pathway in the caffeine potentiation of ketorolac-induced antinociception.

Citric Acid Alternative to Nitric Acid Passivation

NASA Technical Reports Server (NTRS)

Lewis, Pattie L. (Compiler)

2013-01-01

The Ground Systems Development and Operations GSDO) Program at NASA John F. Kennedy Space Center (KSC) has the primary objective of modernizing and transforming the launch and range complex at KSC to benefit current and future NASA programs along with other emerging users. Described as the launch support and infrastructure modernization program in the NASA Authorization Act of 2010, the GSDO Program will develop and implement shared infrastructure and process improvements to provide more flexible, affordable, and responsive capabilities to a multi-user community. In support of the GSDO Program, the purpose of this project is to demonstratevalidate citric acid as a passivation agent for stainless steel. Successful completion of this project will result in citric acid being qualified for use as an environmentally preferable alternative to nitric acid for passivation of stainless steel alloys in NASA and DoD applications.

Anti-Inflammatory Activity of Tanzawaic Acid Derivatives from a Marine-Derived Fungus Penicillium steckii 108YD142

PubMed Central

Shin, Hee Jae; Pil, Gam Bang; Heo, Soo-Jin; Lee, Hyi-Seung; Lee, Jong Seok; Lee, Yeon-Ju; Lee, Jihoon; Won, Ho Shik

2016-01-01

Chemical investigation of a marine-derived fungus, Penicillium steckii 108YD142, resulted in the discovery of a new tanzawaic acid derivative, tanzawaic acid Q (1), together with four known analogues, tanzawaic acids A (2), C (3), D (4), and K (5). The structures of tanzawaic acid derivatives 1–5 were determined by the detailed analysis of 1D, 2D NMR and LC-MS data, along with chemical methods and literature data analysis. These compounds significantly inhibited nitric oxide (NO) production and the new tanzawaic acid Q (1) inhibited the lipopolysaccharide (LPS)-induced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins and mRNA expressions in RAW 264.7 macrophages. Additionally, compound 1 reduced the mRNA levels of inflammatory cytokines. Taken together, the results of this study demonstrated that the new tanzawaic acid derivative inhibits LPS-induced inflammation. This is the first report on the anti-inflammatory activity of tanzawaic acid Q (1). PMID:26761016

Adsorption mechanism of 2,4-dichlorophenoxyacetic acid onto nitric-acid-modified activated carbon fiber.

PubMed

Li, Qun; Sun, Jie; Ren, Tianhao; Guo, Lin; Yang, Zhilin; Yang, Qi; Chen, Hai

2018-04-01

Adsorption by carbon materials is one of the relatively fast methods in present research, which is widely used in emergency events. Activated carbon fiber (ACF) modified by nitric acid (N-ACF) was studied in this research to determine the adsorption performance for 2,4-dichlorophenoxyacetic acid (2,4-D). Subsequently, influence factors, adsorption isotherm models, kinetics and thermodynamic were investigated in a batch system to realize this adsorption. Experimental results showed that ACF modified by 0.1M nitric acid had a better removal ability than 2,4-D. Removal rate of 2,4-D by N-ACF was greatly influenced by pH with the optimum pH at 2. The superiority of the Langmuir isotherm model in describing the adsorption equilibrium was revealed by correlation coefficients R2 (R 2  ≥ 0.997). Furthermore, adsorption kinetics was well described by pseudo-second-order model. The results of thermodynamic showed that adsorption was a spontaneous, endothermic process with randomness increasing. Additionally, surface structure properties of adsorbent were characterized by Scanning electron microscopy, Fourier transform infrared spectroscopy, Specific surface area analysis of Brunauer, Emmett and Teller and Boehm's titration. It turned out that the micropore structure and functional groups on N-ACF all can contribute to the removal of 2,4-D.

Beneficial effects of coconut water feeding on lipid metabolism in cholesterol-fed rats.

PubMed

Sandhya, V G; Rajamohan, T

2006-01-01

The purpose of this study was to determine the effect of coconut water feeding in cholesterol-fed rats. Male albino rats were fed tender coconut water and mature coconut water at a dose level of 4 mL/100 g of body weight. Cholesterol feeding caused a marked increase in total cholesterol, very low-density lipoprotein (VLDL) + low-density lipoprotein (LDL) cholesterol, and triglycerides in serum. Administration of coconut water counteracts the increase in total cholesterol, VLDL + LDL cholesterol, and triglycerides, while high-density lipoprotein cholesterol was higher. Lipid levels in the tissues viz. liver, heart, kidney, and aorta were markedly decreased in cholesterol-fed rats supplemented with coconut water. Feeding coconut water resulted in increased activities of 3-hydroxy-3-methylglutaryl-CoA reductase in liver, lipoprotein lipase in heart and adipose tissue, and plasma lecithin:cholesterol acyl transferase, while lipogenic enzymes showed decreased activities. An increased rate of cholesterol conversion to bile acid and an increased excretion of bile acids and neutral sterols were observed in rats fed coconut water. Histopathological studies of liver and aorta revealed much less fatty accumulation in these tissues in cholesterol-fed rats supplemented with coconut water. Feeding coconut water resulted in increased plasma L-arginine content, urinary nitrite level, and nitric oxide synthase activity. These results indicate that both tender and mature coconut water has beneficial effects on serum and tissue lipid parameters in rats fed cholesterol-containing diet.

Reduction Rates for Higher Americium Oxidation States in Nitric Acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grimes, Travis Shane; Mincher, Bruce Jay; Schmitt, Nicholas C

The stability of hexavalent americium was measured using multiple americium concentrations and nitric acid concentrations after contact with the strong oxidant sodium bismuthate. Contrary to our hypotheses Am(VI) was not reduced faster at higher americium concentrations, and the reduction was only zero-order at short time scales. Attempts to model the reduction kinetics using zero order kinetic models showed Am(VI) reduction in nitric acid is more complex than the autoreduction processes reported by others in perchloric acid. The classical zero-order reduction of Am(VI) was found here only for short times on the order of a few hours. We did show thatmore » the rate of Am(V) production was less than the rate of Am(VI) reduction, indicating that some Am(VI) undergoes two electron-reduction to Am(IV). We also monitored the Am(VI) reduction in contact with the organic diluent dodecane. A direct comparison of these results with those in the absence of the organic diluent showed the reduction rates for Am(VI) were not statistically different for both systems. Additional americium oxidations conducted in the presence of Ce(IV)/Ce(III) ions showed that Am(VI) is reduced without the typical growth of Am(V) observed in the systems sans Ce ion. This was an interesting result which suggests a potential new reduction/oxidation pathway for Am in the presence of Ce; however, these results were very preliminary, and will require additional experiments to understand the mechanism by which this occurs. Overall, these studies have shown that hexavalent americium is fundamentally stable enough in nitric acid to run a separations process. However, the complicated nature of the reduction pathways based on the system components is far from being rigorously understood.« less

Improvement of oxygen-containing functional groups on olive stones activated carbon by ozone and nitric acid for heavy metals removal from aqueous phase.

PubMed

Bohli, Thouraya; Ouederni, Abdelmottaleb

2016-08-01

Recently, modification of surface structure of activated carbons in order to improve their adsorption performance toward especial pollutants has gained great interest. Oxygen-containing functional groups have been devoted as the main responsible for heavy metal binding on the activated carbon surface; their introduction or enhancement needs specific modification and impregnation methods. In the present work, olive stones activated carbon (COSAC) undergoes surface modifications in gaseous phase using ozone (O3) and in liquid phase using nitric acid (HNO3). The activated carbon samples were characterized using N2 adsorption-desorption isotherm, SEM, pHpzc, FTIR, and Boehm titration. The activated carbon parent (COSAC) has a high surface area of 1194 m(2)/g and shows a predominantly microporous structure. Oxidation treatments with nitric acid and ozone show a decrease in both specific surface area and micropore volumes, whereas these acidic treatments have led to a fixation of high amount of surface oxygen functional groups, thus making the carbon surface more hydrophilic. Activated carbon samples were used as an adsorbent matrix for the removal of Co(II), Ni(II), and Cu(II) heavy metal ions from aqueous solutions. Adsorption isotherms were obtained at 30 °C, and the data are well fitted to the Redlich-Peterson and Langmuir equation. Results show that oxidized COSACs, especially COSAC(HNO3), are capable to remove more Co(II), Cu(II), and Ni(II) from aqueous solution. Nitric acid-oxidized olive stones activated carbon was tested in its ability to remove metal ions from binary systems and results show an important maximum adsorbed amount as compared to single systems.

Application of an optimized total N-nitrosamine (TONO) assay to pools: placing N-nitrosodimethylamine (NDMA) determinations into perspective.

PubMed

Kulshrestha, Pankaj; McKinstry, Katherine C; Fernandez, Bernadette O; Feelisch, Martin; Mitch, William A

2010-05-01

Although N-nitrosodimethylamine (NDMA) has been the most prevalent N-nitrosamine detected in disinfected waters, it remains unclear whether NDMA is indeed the most significant N-nitrosamine or just one representative of a larger pool of N-nitrosamines. A widely used assay applied to quantify nitrite, S-nitrosothiols, and N-nitrosamines in biological samples involves their reduction to nitric oxide by acidic tri-iodide, followed by chemiluminescent detection of the evolved nitric oxide in the gas phase. We here describe an adaptation of this method for analyzing total N-nitrosamine (TONO) concentrations in disinfected pools. Optimal sensitivity for N-nitrosamines was obtained using a reduction solution containing 13.5 mL glacial acetic acid and 1 mL of an aqueous 540 g/L iodide and 114 g/L iodine solution held at 80 degrees C. The method detection limit for N-nitrosamines was 110 nM using 100 microL sample injections and NDMA as a standard. N-nitrosamines featuring a range of polarities were converted to nitric oxide with 75-103% efficiency compared to NDMA. Evaluation of potential interfering species indicated that only nitrite and S-nitrosothiols were a concern, but both interferences were effectively eliminated using group-specific sample pretreatments previously employed for biological samples. To evaluate the low TONO concentrations anticipated for pools, 1 L samples were extracted by continuous liquid-liquid extraction with ethyl acetate for 24 h, and concentrated to 1 mL. N-nitrosamine recovery during extraction ranged from 37-75%, and there was a potential for artifactual nitrosation of amines during solvent reflux in the presence of significant nitrite concentrations, but not at the low nitrite concentrations prevalent in most pools. Using the 1000-fold concentration factor and 56% average extraction efficiency, the method detection limit would be 62 pM (5 ng/L as NDMA). The TONO assay was applied to six pools and their common tap water source in conjunction with analysis for specific nitrosamines. Even accounting for the range of N-nitrosamine extraction recoveries, NDMA accounted for an average of only 13% (range 3-46%) of the total nitrosamine pool.

Corrosion Mechanisms in Brazed Al-Base Alloy Sandwich Structures as a Function of Braze Alloy and Process Variables

DTIC Science & Technology

2013-02-01

aeration solution for 8 hours. A concentrated Nitric acid (HNO3) dip for 15 seconds removed corrosion products prior to post-exposure SEM imaging [25...32 to -37°C under a liquid nitrogen chill at 11.2 V for one minute [10]. The electropolishing solution was a mixture of 1/3 concentrated Nitric acid ...DATES COVERED (From - To) 03/27/06-12/31/12 4. TITLE AND SUBTITLE Corrosion Mechanisms in Brazed Al-Base Alloy Sandwich Structures as a Function

Electrolytic Removal of Nitrate From CELSS Crop Residues

NASA Technical Reports Server (NTRS)

Colon, Guillermo; Sager, John

1996-01-01

The controlled ecological life support system (CELSS) resource recovery system is a waste processing system using aerobic and anaerobic bioreactors to recover plant nutrients and secondary foods from inedible biomass. Crop residues contain significant amounts of nitrate which presents two problems: (1) both CELSS biomass production and resource recovery consume large quantities of nitric acid, (2) nitrate causes a variety of problems in both aerobic and anaerobic bioreactors. A technique was proposed to remove the nitrate from potato inedible biomass leachate and to satisfy the nitric acid demand using a four compartment electrolytic cell.

Comment on “Observations of ammonia, nitric acid, and fine particles in a rural gas production region” by Yi Li, Florian M. Schwandnera, H. James Sewell, Angela Zivkovich, Mark Tigges, Suresh Raja, Stephen Holcomb, John V. Molenar, Lincoln Sherman, Cassie Archuleta, Taehyoung Lee and Jeffrey L. Collett Jr. Atmospheric Environment (in press)

NASA Astrophysics Data System (ADS)

Phillips, Gavin J.

2014-05-01

An artefact of the detection of nitric acid (HNO3) by denuder methods is discussed. This artefact arises from the likely reaction of dinitrogen pentoxide (N2O5) on the denuder train resulting in the report of some fraction of N2O5 as HNO3.

Artifacts resembling budding bacteria produced in placer-gold amalgams by nitric acid leaching

USGS Publications Warehouse

Watterson, J.R.

1994-01-01

Microscopic filiform morphologies in gold which are indistinguishable from forms originally interpreted as bacterial in origin were produced in the laboratory by treating amalgams made from natural and artificial gold with hot nitric acid. Textures ranging from cobblestone to deeply crenulated to nodular filiform were produced in the laboratory from all tested natural and artificial gold amalgams; analogous textures widespread in Alaskan placer gold may have a similar inorganic origin. These results indicate that morphology alone cannot be considered adequate evidence of microbial involvement in gold formation.

Artifacts resembling budding bacteria produced in placer-gold amalgams by nitric acid leaching

USGS Publications Warehouse

Watterson, J.R.

1994-01-01

Microscopic filiform morphologies in gold which are indistinguishable from forms originally interpreted as bacterial in origin were produced in the laboratory by treating amalgams made from natural and artificial gold with hot nitric acid. Textures ranging from cobblestone to deeply crenulated to nodular filiform were produced in the laboratory from all tested natural and artificial gold amalgams; analogous textures widespread in Alaskan placer gold may have a similar inorganic origin. These results indicate that morphology alone cannot be considered adequate evidence of microbial involvement in gold formation. -Author

The temperature dependence of the rate constant for the reaction of hydroxyl radicals with nitric acid

NASA Technical Reports Server (NTRS)

Kurylo, M. J.; Cornett, K. D.; Murphy, J. L.

1982-01-01

The rate constant for the reaction of hydroxyl radicals with nitric acid in the 225-443 K temperature range has been measured by means of the flash photolysis resonance fluorescence technique. Above 300 K, the rate constant levels off in a way that can only be explained by the occurrence of two reaction channels, of which one, operative at low temperatures, proceeds through the formation of an adduct intermediate. The implications of these rate constant values for stratospheric reaction constants is discussed.

An Umbrella for Acid Rain.

ERIC Educational Resources Information Center

Randal, Judith

1979-01-01

The Environmental Protection Agency has awarded several grants to study effects of and possible solutions to the problem of "acid rain"; pollution from atmospheric nitric and sulfuric acids. The research program is administered through North Carolina State University at Raleigh and will focus on biological effects of acid rain. (JMF)

Determination of silver in soils, sediments, and rocks by organic-chelate extraction and atomic absorption spectrophotometry

USGS Publications Warehouse

Chao, T.T.; Ball, J.W.; Nakagawa, H.M.

1971-01-01

A useful method for the determination of silver in soil, sediment, and rock samples in geochemical exploration has been developed. The sample is digested with concentrated nitric acid, and the silver extracted with triisooctyl thiophosphate (TOTP) in methyl isobutyl ketone (MIBK) after dilution of the acid digest to approximately 6 M. The extraction of silver into the organic extractant is quantitative and not affected by the nitric acid concentration from 4 M to 8 M, or by different volumes of TOTP-MIBK. The extracted silver is stable and remains in the organic phase up to several days. The silver concentration is determined by atomic absorption spectrophotometry. ?? 1971.

New uses for calcium chloride solution as a mounting medium.

PubMed

Herr, J M

1992-01-01

Fresh cross sections of stems (Psilotum nudum, Coleus blumei, and Pelargonium peltatum) and roots (Setcreasea purpurea) 120 microns thick were fixed in FPA50 (formalin: propionic acid: 50% ethanol, 5:5:90, v/v) for 24 hr and stored in 70% ethanol. The sections were transferred to water and then to 1% phloroglucin in 20% calcium chloride solution plus either hydrochloric, nitric, or lactic acid in the following ratios of phloroglucin-CaCl2 solution:acid: 25:4, 20:2, or 15:5. The sections were mounted on slides either in one of the three mixtures or in fresh 20% calcium chloride solution. A rapid reaction of the acid-phloroglucin with lignin produced a deep red color in tracheary elements and an orange-red color in sclerenchyma. Fixed and stored leaf pieces from Nymphaea odorata were autoclaved in lactic acid, washed in two changes of 95% ethanol, transferred to water, and treated with the three acid-phloroglucin-calcium chloride mixtures. The abundant astrosclereids stained an orange-red color similar to that of sclerenchyma in the sections. In addition, a new method is reported for specifically staining lignified tissues. When sections or leaf pieces are stained in aqueous 0.05% toluidine blue O, then placed in 20% calcium chloride solution, all tissues destain except those with lignified or partially lignified cell walls. Thus, toluidine blue O applied as described becomes a reliable specific test for lignin comparable to the acid-phloroglucin test.

Jellyfish-like few-layer graphene nanoflakes: Synthesis, oxidation, and hydrothermal N-doping

NASA Astrophysics Data System (ADS)

Chernyak, Sergei A.; Podgornova, Angelina M.; Arkhipova, Ekaterina A.; Novotortsev, Roman O.; Egorova, Tolganay B.; Ivanov, Anton S.; Maslakov, Konstantin I.; Savilov, Serguei V.; Lunin, Valery V.

2018-05-01

Few-layer graphene nanoflakes with the bent edges, diameter of 15-40 nm and thickness of 6-7 graphene layers have been synthesized using MgO-templated CVD growth. Their oxidation by nitric acid led to the high oxygen content of 18 at.%, a third of which was attributed to carboxylic groups. Oxidized nanoflakes were post-doped by nitrogen groups using hydrothermal treatment at 220 °C with ammonia and urea water solutions resulting in corresponding nitrogen content of 7 and 5 at.%. Synthesized and treated materials were characterized by XPS, Raman spectroscopy and electron microscopy.

Interhemispheric survey of minor upper atmospheric constituents during October - November 1976

NASA Technical Reports Server (NTRS)

Gauntner, D. J. (Compiler); Haughney, L. C. (Compiler)

1977-01-01

The CV-990 aircraft coordinated several flights with a NASA U-2 aircraft, NOAA ground station measurements in Alaska, Hawaii, and American Samoa, and with Australian and New Zealand ground stations, aircraft, and a balloon experiment in the Southern hemisphere. Data were obtained for species including ozone, total ozone, the oxides of nitrogen, the chlorofluoromethanes, water vapor, nitric acid, carbon monoxide, carbon dioxide, hydrogen chloride, Aitken nuclei, ammonia, aerosols, temperatures, and winds. Individual experiment results and selected analyses are presented. The experimental data include total column densities, latitude variations, interhemisphere differences, and vertical profiles.

URANIUM SEPARATION PROCESS

DOEpatents

Hyde, E.K.; Katzin, L.I.; Wolf, M.J.

1959-07-14

The separation of uranium from a mixture of uranium and thorium by organic solvent extraction from an aqueous solution is described. The uranium is separrted from an aqueous mixture of uranium and thorium nitrates 3 N in nitric acid and containing salting out agents such as ammonium nitrate, so as to bring ihe total nitrate ion concentration to a maximum of about 8 N by contacting the mixture with an immiscible aliphatic oxygen containing organic solvent such as diethyl carbinol, hexone, n-amyl acetate and the like. The uranium values may be recovered from the organic phase by back extraction with water.

Hydrogen ion speciation in the acid precipitation of the northeastern United States

Treesearch

James N. Galloway; Gene E. Likens; Eric S. Edgerton

1976-01-01

The acidity of precipitation in rural, forested areas of the northeastern United States is dominated by the strong mineral acids, sulfuric and nitric. Weak acids have a negligible effect on the measured acidity (pH) of precipitation. These conclusions are based on total acidity titrations and detailed analysis of organic and inorganic components in precipitation.

The contribution of human activities to dissolved inorganic carbon fluxes in a karst underground river system: evidence from major elements and δ¹³C(DIC) in Nandong, Southwest China.

PubMed

Jiang, Yongjun

2013-09-01

Generally, the DIC in karst groundwater is dominantly derived from carbonate dissolution by carbonic acid. However, recently increases in the inorganic carbon flux have been linked to human activities, which nitric and sulfuric acids may contribute to carbonate dissolution. In order to quantify the sources and fluxes of DIC, and evaluate the carbon isotopic evolution of groundwater in Southwest China, the carbonate dissolution by carbonic, sulfuric and nitric acids was evaluated by hydrochemistry and δ¹³C(DIC)of groundwater. The results show that: (1) groundwater collected from residential and agricultural areas, showed higher DIC concentrations and δ¹³C(DIC) than those in groundwater collected from forested and grass land areas; (2) the contributions of carbonate dissolution by carbonic acid to total DIC concentrations in groundwater collected from forested and grass land areas averaged 99%; (3) the contributions of carbonate dissolution by carbonic acid to total DIC concentrations in groundwater, collected from residential and agricultural areas, varied from 40% to 77% with a mean percentage of 62%; (4) while the contributions of carbonate dissolution by sulfuric and nitric acids to total DIC concentrations in groundwater, collected from residential and agricultural areas, varied from 23% to 60% with a mean percentage of 38%; and (5) the δ¹³C(DIC) approaching a value of around -14‰, with a molar ratio between (Ca²⁺+Mg²⁺) and HCO₃⁻ of around 0.5 in groundwater, indicated that the carbonate was dissolved by soil CO₂ from C₃ vegetation under open system conditions. While the δ¹³C(DIC) varying from -5‰ to -11‰, with a variational molar ratio between (Ca²⁺+Mg²⁺) and HCO₃⁻ of 0.5 to 0.8 in groundwater, indicated that carbonate dissolution was controlled by soil CO₂ (from C₃ vegetation), HNO₃ and H₂SO₄. Also, this study indicated that the amount of soil or atmospheric CO₂ consumed during carbonate weathering should be critically evaluated when sulfuric or nitric acids are involved. Thus, not only the exports of inorganic carbon have been enhanced, but also the concentrations of nitrate and sulfate in karst groundwater have been elevated due to carbonate dissolution by sulfuric or nitric acid. Copyright © 2013 Elsevier B.V. All rights reserved.

Cacao pod husks as a source of low-methoxyl, highly acetylated pectins able to gel in acidic media.

PubMed

Vriesmann, Lúcia Cristina; de Oliveira Petkowicz, Carmen Lúcia

2017-08-01

Cacao pod husks, the main by-product from cocoa production, have been investigated for pectin isolation. In the present study, the rheological properties of two low-methoxyl (LM) pectins isolated from cacao pod husks using different extraction conditions were evaluated. One pectin was obtained from optimized conditions employing aqueous nitric acid as an extractant, and the other one was extracted with boiling water. Pectin gels (0.99% galacturonic acid equivalent, w/w) were prepared at pH 2.5-3.0 in the presence of 60% sucrose (w/w) and subjected to rheological analysis. Dynamic oscillatory experiments at 25°C indicated that better gels were obtained at the lowest pH (2.5). Steady shear measurements revealed a shear-thinning behavior. The apparent viscosities of the samples increased as pH decreased. Gelation with calcium ions was not observed for either of the highly acetylated LM pectins analyzed. The rheological analysis results showed that despite their high acetyl content, LM pectins extracted by different methods from cacao pod husks were able to form gels at low pH under reduced water activity, suggesting a possible application in acidic products. Copyright © 2017 Elsevier B.V. All rights reserved.

Bolide impacts, acid rain, and biospheric traumas at the Cretaceous-Tertiary boundary

NASA Technical Reports Server (NTRS)

Prinn, Ronald G.; Fegley, Bruce, Jr.

1987-01-01

Two plausible projectiles are considered: an ice-rich long-period comet and a much smaller rock-metal asteroid. In the framework of a proposal addressed by Lewis et al. (1982), it is shown that, while the impact projectiles themselves do not shock-heat the atmosphere very extensively, the supersonic plume of water vapor and rock produced on impact does shock the atmosphere up to global scales and the shock is of sufficient intensity to produce abundant nitric oxide. For example, an ice-rich long-period comet with a mass of 1.25 x 10 to the 16th kg and a velocity of 65 km/s striking the earth would produce about 7 x 10 to the 40th molecules NO through shock-heating of the atmosphere by the high-velocity ejecta plume fragments. Specific attention is given to the fraction of the atmosphere shock-heated, the global circulation of the nitrogen oxides, the effects of the ejecta plume water on acid rain (AR) predictions, the effects of AR on continental soils, the relationship between AR production rates and the total amount of acid needed to acidify the surface oceans, and the longevity of the oceanic acidity event and the exhaled CO2 event and their implications for the environment in the first millenia or so after the impact.

Extraction of rare earth elements from a contaminated cropland soil using nitric acid, citric acid, and EDTA.

PubMed

Tang, Hailong; Shuai, Weitao; Wang, Xiaojing; Liu, Yangsheng

2017-08-01

Rare earth elements (REEs) contamination to the surrounding soil has increased the concerns of health risk to the local residents. Soil washing was first attempted in our study to remediate REEs-contaminated cropland soil using nitric acid, citric acid, and ethylene diamine tetraacetic acid (EDTA) for soil decontamination and possible recovery of REEs. The extraction time, washing agent concentration, and pH value of the washing solution were optimized. The sequential extraction analysis proposed by Tessier was adopted to study the speciation changes of the REEs before and after soil washing. The extract containing citric acid was dried to obtain solid for the X-ray fluorescence (XRF) analysis. The results revealed that the optimal extraction time was 72 h, and the REEs extraction efficiency increased as the agent concentration increased from 0.01 to 0.1 mol/L. EDTA was efficient to extract REEs over a wide range of pH values, while citric acid was around pH 6.0. Under optimized conditions, the average extraction efficiencies of the major REEs in the contaminated soil were 70.96%, 64.38%, and 62.12% by EDTA, nitric acid, and citric acid, respectively. The sequential extraction analyses revealed that most soil-bounded REEs were mobilized or extracted except for those in the residual fraction. Under a comprehensive consideration of the extraction efficiency and the environmental impact, citric acid was recommended as the most suitable agent for extraction of the REEs from the contaminated cropland soils. The XRF analysis revealed that Mn, Al, Si, Pb, Fe, and REEs were the major elements in the extract indicating a possibile recovery of the REEs.

Nitric oxide scavengers differentially inhibit ammonia oxidation in ammonia-oxidizing archaea and bacteria.

PubMed

Sauder, Laura A; Ross, Ashley A; Neufeld, Josh D

2016-04-01

Differential inhibitors are important for measuring the relative contributions of microbial groups, such as ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA), to biogeochemical processes in environmental samples. In particular, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO) represents a nitric oxide scavenger used for the specific inhibition of AOA, implicating nitric oxide as an intermediate of thaumarchaeotal ammonia oxidation. This study investigated four alternative nitric oxide scavengers for their ability to differentially inhibit AOA and AOB in comparison to PTIO. Caffeic acid, curcumin, methylene blue hydrate and trolox were tested onNitrosopumilus maritimus, two unpublished AOA representatives (AOA-6f and AOA-G6) as well as the AOB representative Nitrosomonas europaea All four scavengers inhibited ammonia oxidation by AOA at lower concentrations than for AOB. In particular, differential inhibition of AOA and AOB by caffeic acid (100 μM) and methylene blue hydrate (3 μM) was comparable to carboxy-PTIO (100 μM) in pure and enrichment culture incubations. However, when added to aquarium sponge biofilm microcosms, both scavengers were unable to inhibit ammonia oxidation consistently, likely due to degradation of the inhibitors themselves. This study provides evidence that a variety of nitric oxide scavengers result in differential inhibition of ammonia oxidation in AOA and AOB, and provides support to the proposed role of nitric oxide as a key intermediate in the thaumarchaeotal ammonia oxidation pathway. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Recovery of Vanadium from Magnetite Ore Using Direct Acid Leaching: Optimization of Parameters by Plackett-Burman and Response Surface Methodologies

NASA Astrophysics Data System (ADS)

Nejad, Davood Ghoddocy; Khanchi, Ali Reza; Taghizadeh, Majid

2018-06-01

Recovery of vanadium from magnetite ore by direct acid leaching is discussed. The proposed process, which employs a mixture of nitric and sulfuric acids, avoids pyrometallurgical treatments since such treatment consumes a high amount of energy. To determine the optimum conditions of vanadium recovery, the leaching process is optimized through Plackett-Burman (P-B) design and response surface methodology (RSM). In this respect, temperature (80-95°C), liquid to solid ratio (L/S) (3-10 mL g-1), sulfuric acid concentration (3-6 M), nitric acid concentration (5-10 vol.%) and time (4-8 h) are considered as the independent variables. According to the P-B approach, temperature and acid concentrations are, respectively, the most effective parameters in the leaching process. These parameters are optimized using RSM to maximize recovery of vanadium by direct acid leaching. In this way, 86.7% of vanadium can be extracted from magnetic ore.

Recovery of Vanadium from Magnetite Ore Using Direct Acid Leaching: Optimization of Parameters by Plackett-Burman and Response Surface Methodologies

NASA Astrophysics Data System (ADS)

Nejad, Davood Ghoddocy; Khanchi, Ali Reza; Taghizadeh, Majid

2018-03-01

Recovery of vanadium from magnetite ore by direct acid leaching is discussed. The proposed process, which employs a mixture of nitric and sulfuric acids, avoids pyrometallurgical treatments since such treatment consumes a high amount of energy. To determine the optimum conditions of vanadium recovery, the leaching process is optimized through Plackett-Burman (P-B) design and response surface methodology (RSM). In this respect, temperature (80-95°C), liquid to solid ratio (L/S) (3-10 mL g-1), sulfuric acid concentration (3-6 M), nitric acid concentration (5-10 vol.%) and time (4-8 h) are considered as the independent variables. According to the P-B approach, temperature and acid concentrations are, respectively, the most effective parameters in the leaching process. These parameters are optimized using RSM to maximize recovery of vanadium by direct acid leaching. In this way, 86.7% of vanadium can be extracted from magnetic ore.

Development of Novel Method for Rapid Extract of Radionuclides from Solution Using Polymer Ligand Film

NASA Astrophysics Data System (ADS)

Rim, Jung H.

Accurate and fast determination of the activity of radionuclides in a sample is critical for nuclear forensics and emergency response. Radioanalytical techniques are well established for radionuclides measurement, however, they are slow and labor intensive, requiring extensive radiochemical separations and purification prior to analysis. With these limitations of current methods, there is great interest for a new technique to rapidly process samples. This dissertation describes a new analyte extraction medium called Polymer Ligand Film (PLF) developed to rapidly extract radionuclides. Polymer Ligand Film is a polymer medium with ligands incorporated in its matrix that selectively and rapidly extract analytes from a solution. The main focus of the new technique is to shorten and simplify the procedure necessary to chemically isolate radionuclides for determination by alpha spectrometry or beta counting. Five different ligands were tested for plutonium extraction: bis(2-ethylhexyl) methanediphosphonic acid (H2DEH[MDP]), di(2-ethyl hexyl) phosphoric acid (HDEHP), trialkyl methylammonium chloride (Aliquat-336), 4,4'(5')-di-t-butylcyclohexano 18-crown-6 (DtBuCH18C6), and 2-ethylhexyl 2-ethylhexylphosphonic acid (HEH[EHP]). The ligands that were effective for plutonium extraction further studied for uranium extraction. The plutonium recovery by PLFs has shown dependency on nitric acid concentration and ligand to total mass ratio. H2DEH[MDP] PLFs performed best with 1:10 and 1:20 ratio PLFs. 50.44% and 47.61% of plutonium were extracted on the surface of PLFs with 1M nitric acid for 1:10 and 1:20 PLF, respectively. HDEHP PLF provided the best combination of alpha spectroscopy resolution and plutonium recovery with 1:5 PLF when used with 0.1M nitric acid. The overall analyte recovery was lower than electrodeposited samples, which typically has recovery above 80%. However, PLF is designed to be a rapid field deployable screening technique and consistency is more important than recovery. PLFs were also tested using blind quality control samples and the activities were accurately measured. It is important to point out that PLFs were consistently susceptible to analytes penetrating and depositing below the surface. The internal radiation within the body of PLF is mostly contained and did not cause excessive self-attenuation and peak broadening in alpha spectroscopy. The analyte penetration issue was beneficial in the destructive analysis. H2DEH[MDP] PLF was tested with environmental samples to fully understand the capabilities and limitations of the PLF in relevant environments. The extraction system was very effective in extracting plutonium from environmental water collected from Mortandad Canyon at Los Alamos National Laboratory with minimal sample processing. Soil samples were tougher to process than the water samples. Analytes were first leached from the soil matrixes using nitric acid before processing with PLF. This approach had a limitation in extracting plutonium using PLF. The soil samples from Mortandad Canyon, which are about 1% iron by weight, were effectively processed with the PLF system. Even with certain limitations of the PLF extraction system, this technique was able to considerably decrease the sample analysis time. The entire environmental sample was analyzed within one to two days. The decrease in time can be attributed to the fact that PLF is replacing column chromatography and electrodeposition with a single step for preparing alpha spectrometry samples. The two-step process of column chromatography and electrodeposition takes a couple days to a week to complete depending on the sample. The decrease in time and the simplified procedure make this technique a unique solution for application to nuclear forensics and emergency response. A large number of samples can be quickly analyzed and selective samples can be further analyzed with more sensitive techniques based on the initial data. The deployment of a PLF system as a screening method will greatly reduce a total analysis time required to gain meaningful isotopic data for the nuclear forensics application. (Abstract shortened by UMI.)

Low to middle tropospheric profiles and biosphere/troposphere fluxes of acidic gases in the summertime Canadian taiga

NASA Technical Reports Server (NTRS)

Klemm, O.; Talbot, R. W.; Fitzgerald, D. R.; Klemm, K. I.; Lefer, B. L.

1994-01-01

We report features of acidic gases in the troposphere from 9 to 5000 m altitude above ground over the Canadian taiga in the summer of 1990. The measurements were conducted at a 30-m meteorological tower and from the NASA Wallops Electra aircraft as part of the joint U.S.-Canadian Arctic Boundary Layer Expedition (ABLE) 3B Northern Wetland Studies (NOWES). We sampled air for acidic gases using the mist chamber collector coupled with subsequent analysis using ion chromatography. At the tower we collected samples at two heights during a 13-day period, including diurnal studies. Using eddy flux and profile data, we estimated the biosphere/troposphere fluxes of nitric, formic, and acetic acids and sulfur dioxide. For the organic acids, emissions from the taiga in the afternoon hours and deposition during the predawn morning hours were observed. The flux intensities alone were however not high enough to explain the observed changes in mixing ratios. The measured deposition fluxes of nitric acid were high enough to have a significant influence on its mixing ratio in the boundary layer. On three days we measured vertical profiles of nitric, formic, and acetic acids through the lower to midtroposphere. We found that the chemical composition of the troposphere was extremely heterogenous. Pronounced layers of polluted air were readily apparent from our measurements. Local photochemical production and episodic long-range transport of trace components, originating from biomass burning and possibly industrial emissions, appear to have a strong influence on the composition of the troposphere and biosphere/troposphere fluxes of acidic gases at this site.

Heterogeneous Reactions of Limonene on Mineral Dust: Impacts of Adsorbed Water and Nitric Acid.

PubMed

Lederer, Madeline R; Staniec, Allison R; Coates Fuentes, Zoe L; Van Ry, Daryl A; Hinrichs, Ryan Z

2016-12-08

Biogenic volatile organic compounds (BVOCs), including the monoterpene limonene, are a major source of secondary organic aerosol (SOA). While gas-phase oxidation initiates the dominant pathway for BVOC conversion to SOA, recent studies have demonstrated that biogenic hydrocarbons can also directly react with acidic droplets. To investigate whether mineral dust may facilitate similar reactive uptake of biogenic hydrocarbons, we studied the heterogeneous reaction of limonene with mineral substrates using condensed-phase infrared spectroscopy and identified the formation of irreversibly adsorbed organic products. For kaolinite, Arizona Test Dust, and silica at 30% relative humidity, GC-MS identified limonene-1,2-diol as the dominant product with total organic surface concentrations on the order of (3-5) × 10 18 molecules m -2 . Experiments with 18 O-labeled water support a mechanism initiated by oxidation of limonene by surface redox sites forming limonene oxide followed by water addition to the epoxide to form limonenediol. Limonene uptake on α-alumina, γ-alumina, and montmorillonite formed additional products in high yield, including carveol, carvone, limonene oxide, and α-terpineol. To model tropospheric processing of mineral aerosol, we also exposed each mineral substrate to gaseous nitric acid prior to limonene uptake and identified similar surface adsorbed products that were formed at rates 2 to 5 times faster than without nitrate coatings. The initial rate of reaction was linearly dependent on gaseous limonene concentration between 5 × 10 12 and 5 × 10 14 molecules cm -3 (0.22-20.5 ppm) consistent with an Eley-Rideal-type mechanism in which gaseous limonene reacts directly with reactive surface sites. Increasing relative humidity decreased the amount of surface adsorbed products indicating competitive adsorption of surface adsorbed water. Using a laminar flow tube reactor we measured the uptake coefficient for limonene on kaolinite at 25% RH to range from γ = 5.1 × 10 -6 to 9.7 × 10 -7 . After adjusting for reactive surface areas, we estimate uptake coefficients for limonene on HNO 3 -processed mineral aerosol on the order of (1-6) × 10 -6 . Although this heterogeneous reaction will not impact the atmospheric lifetime of gaseous limonene, it does provide a new pathway for mineral aerosol to acquire secondary organic matter from biogenic hydrocarbons, which in turn will alter the physical properties of mineral dust.

Indoor organic and inorganic pollutants: In-situ formation and dry deposition in Southeastern Brazil

NASA Astrophysics Data System (ADS)

Allen, Andrew G.; Miguel, Antonio H.

We have measured indoor and outdoor levels of particle- and gas-phase pollutants, collected in offices, restaurants and a hotel at six different sites in and around the cities of São Paulo and Campinas, Brazil, during summer 1993. Gas-phase species included acetic acid, formic acid, nitrous acid, hydrochloric acid, sulfur dioxide, nitric acid, oxalic acid, and pyruvic acid. Fine mode (< 3 μm dp) and coarse mode (> 3 μm dp) species measured included chloride, potassium, acetate, nitrate, magnesium, formate, sodium, pyruvate, nitrite, calcium, sulfate, oxalate, and ammonium. One sample (˜ 6 h) was simultaneously collected indoors and outdoors at each site during regular working hours. Indoor samplers were located ca. 1.5 m from the floor, and the outdoors immediately outside the window. Indoor/outdoor concentration ratios suggest that fine potassium chloride was produced indoors in appreciable amounts at both restaurants studied and, to a lesser extent, in the three offices as well. Indoor fine nitrate particles found in restaurants appear to have been produced by fuel combustion; a small fraction may have resulted from dry deposition of nitric acid onto existing fine particles. Indoor and outdoor concentrations of fine- and coarse-mode acetate suggest their production at all sites. The average concentration of gas-phase acetic acid was 42 μg m -3 indoors compared to 9.0 μg m -3 outdoors. In-situ formation of nitrous acid and acetic acid appears to have occurred at all indoor sites. High levels of formic and acetic acids were produced indoors at a pizzeria that used wood for cooking. Nitrous acid average concentrations for all sites were 8.4 μm m -3 indoors and 3.2 μm m -3 outdoors. Indoor/outdoor ratios at all sites suggest that dry deposition indoors may have occurred for hydrochloric acid, nitric acid and sulfur dioxide and that fine-mode sulfate infiltrate buildings from outside at most sites.

Anthropogenically enhanced chemical weathering and carbon evasion in the Yangtze Basin

PubMed Central

Guo, Jingheng; Wang, Fushun; Vogt, Rolf David; Zhang, Yuhang; Liu, Cong-Qiang

2015-01-01

Chemical weathering is a fundamental geochemical process regulating the atmosphere-land-ocean fluxes and earth’s climate. It is under natural conditions driven primarily by weak carbonic acid that originates from atmosphere CO2 or soil respiration. Chemical weathering is therefore assumed as positively coupled with its CO2 consumption in contemporary geochemistry. Strong acids (i.e. sulfuric- and nitric acid) from anthropogenic sources have been found to influence the weathering rate and CO2 consumption, but their integrated effects remain absent in the world largest river basins. By interpreting the water chemistry and overall proton budget in the Yangtze Basin, we found that anthropogenic acidification had enhanced the chemical weathering by 40% during the past three decades, leading to an increase of 30% in solute discharged to the ocean. Moreover, substitution of carbonic acid by strong acids increased inorganic carbon evasion, offsetting 30% of the CO2 consumption by carbonic weathering. Our assessments show that anthropogenic loadings of sulfuric and nitrogen compounds accelerate chemical weathering but lower its CO2 sequestration. These findings have significant relevance to improving our contemporary global biogeochemical budgets. PMID:26150000

Batch leaching tests of motherboards to assess environmental contamination by bromine, platinum group elements and other selected heavy metals.

PubMed

Almeida, César; Grosselli, Melina; González, Patricia; Martínez, Dante; Gil, Raúl

2016-02-01

In this study, a batch leaching test was executed to evaluate the toxicity associated with chemicals contained in motherboards. The leaching solutions used were distilled water, nitric acid, acetic acid and synthetic acid rain solution. A total of 21 elements including Ag, As, Au, Br, Cd, Co, Cr, Cu, Hf, Ir, Mn, Ni, Os, Pb, Pd, Pt, Rd, Rh, Se, U and Zn were analyzed. In this study, the pH values of all the leachates fell within the range of 2.33-4.88. The highest concentrations of metals were obtained from the acid rain solution, whilst the maximum value of bromine was achieved with solution of acetic acid. Appreciable concentrations of platinum group elements were detected with concentrations around 3.45, 1.43, 1.21 and 22.19 µg L(-1) for Ir, Pd, Pt and Rh, respectively. The different leaching of the motherboards revealed the predominant presence of the toxic substances in the leached from the e-waste. Copyright © 2015 Elsevier Ltd. All rights reserved.

Participation of HNO3 CIMS Instrument in the Sage III Ozone Loss and Validation Experiment (SOLVE)

NASA Technical Reports Server (NTRS)

Eisele, F. L.

2001-01-01

This project was part of a larger SOLVE project led by Paul Wennberg at California Institute of Technology. The work completed on this project included participating in the installation and preflight testing of a new chemical ionization mass spectrometer for measuring gas and particle phase nitric acid on the ER-2. The investigators subsequently participated in SOLVE where additional instrument improvements were made and a substantial data set was generated. The two Georgia Tech investigators that participated in this work (Fred Eisele and Dave Tanner) had previously been responsible for much of the design and construction of the ion source and mass spectrometer which would be used to measure HNO3 in SOLVE, with Caltech focusing on inlets, calibration, gas supplies/pumping computer control, and overall integration. Thus, a similar focus remained during the SOLVE measurements though all investigators worked on most if not all aspects of the instrument at some point in the mission. Some of the more interesting results from the study included measurements of nitric acid on what are thought to be 5-20 microns diameter individual particles which could supply a local mechanism for HNO3 removal, Nitric acid measurements on SOLVE were completed as a collaborative effort with a great deal of overlap between this project and the larger parent project led by Paul Wennberg. As such, the instrumentation used, its operation, and the resulting measurements are far more fully discussed in the attached report (appendix A) which describes the joint SOLVE nitric acid measurement effort.

L-arginine: a new opportunity in the management of clinical derangements in dialysis patients.

PubMed

Bellinghieri, Guido; Santoro, Domenico; Mallamace, Agostino; Di Giorgio, Rosa Maria; De Luca, Grazia; Savica, Vincenzo

2006-07-01

L-Arginine is an essential amino acid for infants and growing children, as well as for pregnant women. This amino acid is a substrate for at least 5 enzymes identified in mammals, including arginase, arginine-glycine transaminase, kyotorphine synthase, nitric oxide synthase, and arginine decarboxylase. L-arginine is essential for the synthesis of creatine, urea, polyamines, nitric oxide, and agmatine. Arginine may be considered an essential amino acid in sepsis, and its supplementation could be beneficial in this clinical setting by improving microcirculation and protein anabolism. Rats receiving arginine-supplemented parenteral nutrition showed an increased ability to synthesize acute phase proteins when challenged with sepsis. Finally, L-arginine exerts antihypertensive and antiproliferative effects on vascular smooth muscles. It has been shown to reduce systemic blood pressure in some forms of experimental hypertension. Endothelial dysfunction and reduced nitric oxide bioactivity are associated with increased incidence of cardiovascular diseases. A beneficial effect of acute and chronic L-arginine supplementation on endothelial derived nitric oxide production and endothelial function has been shown. In end-stage renal disease patients, the rate of de novo arginine synthesis seemed to be preserved. Our preliminary data on a group of dialysis patients showed that predialysis arginine levels were stable in a normal range during the dialysis session and that hypertensive patients had lower arginine-citrulline ratio than normotensive patients.

The application of N,N-dimethyl-3-oxa-glutaramic acid (DOGA) in the PUREX process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jianchen, Wang; Jing, Chen

2007-07-01

The new salt-free complexant, DOGA for separating trace Pu(IV) and Np(IV) from U(VI) nitric acid solution was studied. DOGA has stronger complexing abilities to Pu(IV) and Np(IV), but complexing ability of DOGA to U(VI) was weaker. The DOGA can be used in the PUREX process to separate Pu(IV) and Np(IV) from U(VI) nitric solution. On one hand, U(IV) in the nitric acid solution containing trace Pu(IV) and Np(IV) was extracted by 30%TBP - kerosene(v/v) in the presence of DOGA, but Pu(IV) and Np(IV) were kept in the aqueous phase. On the other hand, Pu(IV) and Np(IV) loading in 30% TBPmore » - kerosene were effectively stripped by DOGA into the aqueous phase, but U(VI) loading in 30% TBP - kerosene was remained in 30% TBP - kerosene. DOGA is a promising complexant to separate Pu(IV) and Np(IV) from U(VI) solution in the U-cycle of the PUREX process. (authors)« less

An investigation into the surface heterogeneity of nitric acid oxidized carbon fiber

NASA Astrophysics Data System (ADS)

Woodhead, Andrea L.; de Souza, Mandy L.; Church, Jeffrey S.

2017-04-01

The carbon fiber surface plays a critical role in the performance of carbon fiber composite materials and, thus it is important to have a thorough understanding of the fiber surface. A series of nitric acid treated intermediate modulus carbon fibers with increasing treatment level was prepared and characterized using a range of surface sensitive techniques including Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), X-ray Photoelectron Spectroscopy (XPS) and Raman spectroscopy. The results, which were found to be consistent with increasing treatment levels, were compared to the literature. Raman spectral mapping has been used to investigate the heterogeneity of the carbon fiber surface after nitric acid oxidation. The mapping enabled the effects of surface treatment on carbon fiber to be investigated at a spatial resolution unattainable by XPS and provided chemical structure information not provided by SEM or AFM. The highest level of treatment resulted in the most heterogeneous surface. Raman mapping, while time consuming, can provide valuable information which can lead to an enhanced understanding of the heterogeneity of the carbon fiber surface.

Decontamination of uranium-contaminated waste oil using supercritical fluid and nitric acid.

PubMed

Sung, Jinhyun; Kim, Jungsoo; Lee, Youngbae; Seol, Jeunggun; Ryu, Jaebong; Park, Kwangheon

2011-07-01

The waste oil used in nuclear fuel processing is contaminated with uranium because of its contact with materials or environments containing uranium. Under current law, waste oil that has been contaminated with uranium is very difficult to dispose of at a radioactive waste disposal site. To dispose of the uranium-contaminated waste oil, the uranium was separated from the contaminated waste oil. Supercritical R-22 is an excellent solvent for extracting clean oil from uranium-contaminated waste oil. The critical temperature of R-22 is 96.15 °C and the critical pressure is 49.9 bar. In this study, a process to remove uranium from the uranium-contaminated waste oil using supercritical R-22 was developed. The waste oil has a small amount of additives containing N, S or P, such as amines, dithiocarbamates and dialkyldithiophosphates. It seems that these organic additives form uranium-combined compounds. For this reason, dissolution of uranium from the uranium-combined compounds using nitric acid was needed. The efficiency of the removal of uranium from the uranium-contaminated waste oil using supercritical R-22 extraction and nitric acid treatment was determined.

Nitric Oxide Mediates Glutamate-Linked Enhancement of cGMP Levels in the Cerebellum

NASA Astrophysics Data System (ADS)

Bredt, David S.; Snyder, Solomon H.

1989-11-01

Nitric oxide, which mediates influences of numerous neurotransmitters and modulators on vascular smooth muscle and leukocytes, can be formed in the brain from arginine by an enzymatic activity that stoichiometrically generates citrulline. We show that glutamate and related amino acids, such as N-methyl-D-aspartate, markedly stimulate arginine-citrulline transformation in cerebellar slices stoichiometrically with enhancement of cGMP levels. Nω-monomethyl-L-arginine blocks the augmentation both of citrulline and cGMP with identical potencies. Arginine competitively reverses both effects of Nω-monomethyl-L-arginine with the same potencies. Hemoglobin, which complexes nitric oxide, prevents the stimulation by N-methyl-D-aspartate of cGMP levels, and superoxide dismutase, which elevates nitric oxide levels, increases cGMP formation. These data establish that nitric oxide mediates the stimulation by glutamate of cGMP formation.

Characterization of citrus pectin samples extracted under different conditions: influence of acid type and pH of extraction

PubMed Central

Kaya, Merve; Sousa, António G.; Crépeau, Marie-Jeanne; Sørensen, Susanne O.; Ralet, Marie-Christine

2014-01-01

Background and Aims Pectin is a complex macromolecule, the fine structure of which is influenced by many factors. It is used as a gelling, thickening and emulsifying agent in a wide range of applications, from food to pharmaceutical products. Current industrial pectin extraction processes are based on fruit peel, a waste product from the juicing industry, in which thousands of tons of citrus are processed worldwide every year. This study examines how pectin components vary in relation to the plant source (orange, lemon, lime, grapefruit) and considers the influence of extraction conditions on the chemical and macromolecular characteristics of pectin samples. Methods Citrus peel (orange, lemon, lime and grapefruit) from a commercial supplier was used as raw material. Pectin samples were obtained on a bulk plant scale (kilograms; harsh nitric acid, mild nitric acid and harsh oxalic acid extraction) and on a laboratory scale (grams; mild oxalic acid extraction). Pectin composition (acidic and neutral sugars) and physicochemical properties (molar mass and intrinsic viscosity) were determined. Key Results Oxalic acid extraction allowed the recovery of pectin samples of high molecular weight. Mild oxalic acid-extracted pectins were rich in long homogalacturonan stretches and contained rhamnogalacturonan I stretches with conserved side chains. Nitric acid-extracted pectins exhibited lower molecular weights and contained rhamnogalacturonan I stretches encompassing few and/or short side chains. Grapefruit pectin was found to have short side chains compared with orange, lime and lemon. Orange and grapefruit pectin samples were both particularly rich in rhamnogalacturonan I backbones. Conclusions Structural, and hence macromolecular, variations within the different citrus pectin samples were mainly related to their rhamnogalacturonan I contents and integrity, and, to a lesser extent, to the length of their homogalacturonan domains. PMID:25081519

FY13 GLYCOLIC-NITRIC ACID FLOWSHEET DEMONSTRATIONS OF THE DWPF CHEMICAL PROCESS CELL WITH SIMULANTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, D.; Zamecnik, J.; Best, D.

Savannah River Remediation is evaluating changes to its current Defense Waste Processing Facility flowsheet to replace formic acid with glycolic acid in order to improve processing cycle times and decrease by approximately 100x the production of hydrogen, a potentially flammable gas. Higher throughput is needed in the Chemical Processing Cell since the installation of the bubblers into the melter has increased melt rate. Due to the significant maintenance required for the safety significant gas chromatographs and the potential for production of flammable quantities of hydrogen, eliminating the use of formic acid is highly desirable. Previous testing at the Savannah Rivermore » National Laboratory has shown that replacing formic acid with glycolic acid allows the reduction and removal of mercury without significant catalytic hydrogen generation. Five back-to-back Sludge Receipt and Adjustment Tank (SRAT) cycles and four back-to-back Slurry Mix Evaporator (SME) cycles were successful in demonstrating the viability of the nitric/glycolic acid flowsheet. The testing was completed in FY13 to determine the impact of process heels (approximately 25% of the material is left behind after transfers). In addition, back-to-back experiments might identify longer-term processing problems. The testing was designed to be prototypic by including sludge simulant, Actinide Removal Product simulant, nitric acid, glycolic acid, and Strip Effluent simulant containing Next Generation Solvent in the SRAT processing and SRAT product simulant, decontamination frit slurry, and process frit slurry in the SME processing. A heel was produced in the first cycle and each subsequent cycle utilized the remaining heel from the previous cycle. Lower SRAT purges were utilized due to the low hydrogen generation. Design basis addition rates and boilup rates were used so the processing time was shorter than current processing rates.« less

46 CFR 153.1011 - Changing containment systems and hoses to and from alkylene oxide service.

Code of Federal Regulations, 2012 CFR

2012-10-01

... reactive with alkylene oxides: (1) Non-oxidizing mineral acids (e.g. hydrochloric, phosphoric); (2) Sulfuric acid; (3) Nitric acid; (4) Organic acids (e.g. acetic, formic); (5) Halogenated organic acids (e.g... condition with no heavy rust accumulations or traces of previous cargoes; (2) No alkylene oxide is loaded...

46 CFR 153.1011 - Changing containment systems and hoses to and from alkylene oxide service.

Code of Federal Regulations, 2011 CFR

2011-10-01

... reactive with alkylene oxides: (1) Non-oxidizing mineral acids (e.g. hydrochloric, phosphoric); (2) Sulfuric acid; (3) Nitric acid; (4) Organic acids (e.g. acetic, formic); (5) Halogenated organic acids (e.g... condition with no heavy rust accumulations or traces of previous cargoes; (2) No alkylene oxide is loaded...

46 CFR 153.1011 - Changing containment systems and hoses to and from alkylene oxide service.

Code of Federal Regulations, 2014 CFR

2014-10-01

... reactive with alkylene oxides: (1) Non-oxidizing mineral acids (e.g. hydrochloric, phosphoric); (2) Sulfuric acid; (3) Nitric acid; (4) Organic acids (e.g. acetic, formic); (5) Halogenated organic acids (e.g... condition with no heavy rust accumulations or traces of previous cargoes; (2) No alkylene oxide is loaded...

46 CFR 153.1011 - Changing containment systems and hoses to and from alkylene oxide service.

Code of Federal Regulations, 2010 CFR

2010-10-01

... reactive with alkylene oxides: (1) Non-oxidizing mineral acids (e.g. hydrochloric, phosphoric); (2) Sulfuric acid; (3) Nitric acid; (4) Organic acids (e.g. acetic, formic); (5) Halogenated organic acids (e.g... condition with no heavy rust accumulations or traces of previous cargoes; (2) No alkylene oxide is loaded...

46 CFR 153.1011 - Changing containment systems and hoses to and from alkylene oxide service.

Code of Federal Regulations, 2013 CFR

2013-10-01

... reactive with alkylene oxides: (1) Non-oxidizing mineral acids (e.g. hydrochloric, phosphoric); (2) Sulfuric acid; (3) Nitric acid; (4) Organic acids (e.g. acetic, formic); (5) Halogenated organic acids (e.g... condition with no heavy rust accumulations or traces of previous cargoes; (2) No alkylene oxide is loaded...

Study to find the best extraction solvent for use with guava leaves (Psidium guajava L.) for high antioxidant efficacy

PubMed Central

Seo, Jongkwon; Lee, Soojung; Elam, Marcus L; Johnson, Sarah A; Kang, Jonghoon; Arjmandi, Bahram H

2014-01-01

The effects of guava leaves extracted using solvents of water, ethanol, methanol, and different concentrations of hydroethanolic solvents on phenolic compounds and flavonoids, and antioxidant properties have been investigated. The antioxidant capability was assessed based on 2,2-diphenyl-1-picrylhydrazyl radical and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical-scavenging abilities, reducing power, and nitric oxide-and nitrate-scavenging activities. The results demonstrated that the antioxidant ability of guava leaf extracts has a strong relationship with phenolic compound content rather than flavonoid content. Phenolic compound content of water extracted guava leaves was higher compared to pure ethanol and methanol extracts. However, phenolic compound content extracted using hydroethanolic solvent was higher than water, whereas 50% hydroethanolic was observed to be the most effective solvent showing high antioxidant ability. PMID:24804076

Optimized polymeric film-based nitric oxide delivery inhibits bacterial growth in a mouse burn wound model.

PubMed

Brisbois, Elizabeth J; Bayliss, Jill; Wu, Jianfeng; Major, Terry C; Xi, Chuanwu; Wang, Stewart C; Bartlett, Robert H; Handa, Hitesh; Meyerhoff, Mark E

2014-10-01

Nitric oxide (NO) has many biological roles (e.g. antimicrobial agent, promoter of angiogenesis, prevention of platelet activation) that make NO releasing materials desirable for a variety of biomedical applications. Localized NO release can be achieved from biomedical grade polymers doped with diazeniumdiolated dibutylhexanediamine (DBHD/N2O2) and poly(lactic-co-glycolic acid) (PLGA). In this study, the optimization of this chemistry to create film/patches that can be used to decrease microbial infection at wound sites is examined. Two polyurethanes with different water uptakes (Tecoflex SG-80A (6.2±0.7wt.%) and Tecophilic SP-60D-20 (22.5±1.1wt.%)) were doped with 25wt.% DBHD/N2O2 and 10wt.% of PLGA with various hydrolysis rates. Films prepared with the polymer that has the higher water uptake (SP-60D-20) were found to have higher NO release and for a longer duration than the polyurethane with the lower water uptake (SG-80A). The more hydrophilic polymer enhances the hydrolysis rate of the PLGA additive, thereby providing a more acidic environment that increases the rate of NO release from the NO donor. The optimal NO releasing and control SG-80A patches were then applied to scald burn wounds that were infected with Acinetobacter baumannii. The NO released from these patches applied to the wounds is shown to significantly reduce the A. baumannii infection after 24h (∼4 log reduction). The NO release patches are also able to reduce the level of transforming growth factor-β in comparison to controls, which can enhance re-epithelialization, decrease scarring and reduce migration of bacteria. The combined DBHD/N2O2 and PLGA-doped polymer patches, which could be replaced periodically throughout the wound healing process, demonstrate the potential to reduce risk of bacterial infection and promote the overall wound healing process. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Effects of exogenous glutathione on arsenic burden and NO metabolism in brain of mice exposed to arsenite through drinking water.

PubMed

Wang, Yan; Zhao, Fenghong; Jin, Yaping; Zhong, Yuan; Yu, Xiaoyun; Li, Gexin; Lv, Xiuqiang; Sun, Guifan

2011-03-01

Chronic exposure to inorganic arsenic (iAs) is associated with neurotoxicity. Studies to date have disclosed that methylation of ingested iAs is the main metabolic pathway, and it is a process relying on reduced glutathione (GSH). The aim of this study was to explore the effects of exogenous GSH on arsenic burden and metabolism of nitric oxide (NO) in the brain of mice exposed to arsenite via drinking water. Mice were exposed to sodium arsenite through drinking water contaminated with 50 mg/L arsenic for 4 weeks and treated intraperitoneally with saline solution, 200 mg/kg body weight (b.w), 400 mg/kg b.w, or 800 mg/kg b.w GSH, respectively, at the 4th week. Levels of iAs, monomethylarsenic acid, and dimethylarsenic acid (DMAs) in the liver, blood, and brain were determined by method of hydride generation coupled with atomic absorption spectrophotometry. Activities of nitric oxide synthase (NOS) and contents of NO in the brain were determined by colorimetric method. Compared with mice exposed to arsenite alone, administration of GSH increased dose-dependently the primary and secondary methylation ratio in the liver, which caused the decrease in percent iAs and increase in percent DMAs in the liver, as a consequence, resulted in significant decrease in iAs levels in the blood and total arsenic levels in both blood and brain. NOS activities and NO levels in the brain of mice in iAs group were significantly lower than those in control; however, administration of GSH could increase significantly activities of NOS and contents of NO. Findings from this study suggested that exogenous GSH could promote both primary and secondary arsenic methylation capacity in the liver, which might facilitate excretion of arsenicals, and consequently reduce arsenic burden in both blood and brain and furthermore ameliorate the effects of arsenicals on NO metabolism in the brain.

Optimized polymeric film-based nitric oxide delivery inhibits bacterial growth in a mouse burn wound model

PubMed Central

Brisbois, Elizabeth J.; Bayliss, Jill; Wu, Jianfeng; Major, Terry C.; Xi, Chuanwu; Wang, Stewart C.; Bartlett, Robert H.; Handa, Hitesh; Meyerhoff, Mark E.

2014-01-01

Nitric oxide (NO) has many biological roles (e.g., antimicrobial agent, promoter of angiogenesis, prevention of platelet activation, etc.) that make NO releasing materials desirable for a variety of biomedical applications. Localized NO release can be achieved from biomedical grade polymers doped with diazeniumdiolated dibutylhexanediamine (DBHD/N2O2) and poly(lactic-co-glycolic acid) (PLGA). In this study, the optimization of this chemistry to create film/patches that can be used to decrease microbial infection at wound sites is examined. Two polyurethanes with different water uptakes (Tecoflex SG-80A (6.2 ± 0.7 wt %) and Tecophillic SP-60D-20 (22.5 ± 1.1 wt%)) were doped with 25 wt% DBHD/N2O2 and 10 wt% of PLGA with various hydrolysis rates. Films prepared with the polymer that has the higher water uptake (SP-60D-20) were found to have higher NO release and for a longer duration than the polyurethane with lower water uptake (SG-80A). The more hydrophilic polymer enhances the hydrolysis rate of the PLGA additive, thereby providing a more acidic environment that increases the rate of NO release from the NO donor. The optimal NO releasing and control SG-80A patches were then applied to scald burn wounds that were infected with Acinetobacter baumannii. The NO released from these patches applied to the wounds is shown to significantly reduce the A. baumannii infection after 24 h (~4 log reduction). The NO release patches are also able to reduce the TGF-β levels, in comparison to controls, which can enhance reepithelialization, decrease scarring, and reduce migration of bacteria. The combined DBHD/N2O2 and PLGA-doped polymer patches, which could be replaced periodically throughout the wound healing process, demonstrate the potential to reduce risk of bacterial infection and promote the overall wound healing process. PMID:24980058

Anti-inflammatory activity of hydroxycinnamic acid derivtives isolated from corn bran in lipopolysaccharide-stimulated raw 264.7 macrophages

USDA-ARS?s Scientific Manuscript database

In this study, the effect of the 80 percent ethanolic extract of corn bran (EECB) on inhibition of nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression in lipopolysaccharide (LPS)-stimulated Raw 264.7 cells was investigated. The EECB inhibited LPS induced NO production...

Isolation and purification of a polysaccharide from the caterpillar medicinal mushroom Cordyceps militaris (Ascomycetes) fruit bodies and its immunomodulation of RAW 264.7 macrophages.

PubMed

Zhu, Lina; Tang, Qingjiu; Zhou, Shuai; Liu, Yanfang; Zhang, Zhong; Gao, Xinhua; Wang, Shiping; Wang, Zhaolong

2014-01-01

A novel polysaccharide (CP2-S) was purified from Cordyceps militaris fruit bodies by hot water extraction, ethanol precipitation, DEAE-Sepharose Fast Flow and Sephacryl S-400 high-resolution chromatography. The polysaccharide had a molecular weight of 5.938 × 10(6) g/mol and was mainly composed of glucose. CP2-S had carbohydrate content estimated to be 100% using the phenol-sulfuric acid method. Immunostimulating experiments in vitro indicated that CP2-S could stimulate nitric oxide production, phagocytosis, respiratory burst activity, and secretion of interleukin-1β and interleukin-2 of macrophages, suggesting that this water-soluble polysaccharide from the fruit body of C. militaris is a natural immunostimulating polysaccharide with potential for further application.

Role of nitric oxide in long-term potentiation of the rat medial vestibular nuclei.

PubMed

Grassi, S; Pettorossi, V E

2000-01-01

In rat brainstem slices, we investigated the role of nitric oxide in long-term potentiation induced in the ventral portion of the medial vestibular nuclei by high-frequency stimulation of the primary vestibular afferents. The nitric oxide scavenger [2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide ] and the nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester were administered before and after induction of potentiation. Both drugs completely prevented long-term potentiation, whereas they did not impede the potentiation build-up, or affect the already established potentiation. These results demonstrate that the induction, but not the maintenance of vestibular long-term potentiation, depends on the synthesis and release into the extracellular medium of nitric oxide. In addition, we analysed the effect of the nitric oxide donor sodium nitroprusside on vestibular responses. Sodium nitroprusside induced long-term potentiation, as evidenced through the field potential enhancement and unit peak latency decrease. This potentiation was impeded by D, L-2-amino-5-phosphonopentanoic acid, and was reduced under blockade of synaptosomal platelet-activating factor receptors by ginkgolide B and group I metabotropic glutamate receptors by (R,S)-1-aminoindan-1, 5-dicarboxylic acid. When reduced, potentiation fully developed following the washout of antagonist, demonstrating an involvement of platelet-activating factor and group I metabotropic glutamate receptors in its full development. Potentiation induced by sodium nitroprusside was also associated with a decrease in the paired-pulse facilitation ratio, which persisted under ginkgolide B, indicating that nitric oxide increases glutamate release independently of platelet-activating factor-mediated presynaptic events. We suggest that nitric oxide, released after the activation of N-methyl-D-aspartate receptors, acts as a retrograde messenger leading to an enhancement of glutamate release to a sufficient level for triggering potentiation. Once the synaptic efficacy has changed, it becomes a long-lasting phenomenon only through a subsequent action of platelet-activating factor.

Quantitative RT-PCR Comparison of the Urea and Nitric Oxide Cycle Gene Transcripts in Adult Human Tissues

PubMed Central

Neill, Meaghan Anne; Aschner, Judy; Barr, Frederick; Summar, Marshall L.

2009-01-01

The urea cycle and nitric oxide cycle play significant roles in complex biochemical and physiologic reactions. These cycles have distinct biochemical goals including the clearance of waste nitrogen; the production of the intermediates ornithine, citrulline, and arginine for the urea cycle; and the production of nitric oxide for the nitric oxide pathway. Despite their disparate functions, the two pathways share two enzymes, argininosuccinic acid synthase and argininosuccinic acid lyase, and a transporter, citrin. Studying the gene expression of these enzymes is paramount in understanding these complex biochemical pathways. Here, we examine the expression of genes involved in the urea cycle and the nitric oxide cycle in a panel of eleven different tissue samples obtained from individual adults without known inborn errors of metabolism. In this study, the pattern of co-expressed enzymes provides a global view of the metabolic activity of the urea and nitric oxide cycles in human tissues. Our results show that these transcripts are differentially expressed in different tissues. The pattern of co-expressed enzymes provides a global view of the metabolic activity of the urea and nitric oxide cycles in human tissues. Using the co-expression profiles, we discovered that the combination of expression of enzyme transcripts as detected in our study, might serve to fulfill specific physiologic function(s) in tissue including urea production/nitrogen removal, arginine/citrulline production, nitric oxide production, and ornithine production. Our study reveals the importance of studying not only the expression profile of an enzyme of interest, but also studying the expression profiles of the other enzymes involved in a particular pathway so as to better understand the context of expression. The tissue patterns we observed highlight the variety of important functions they conduct and provide insight into many of the clinical observations from their disruption. PMID:19345634

Information entropy-based fitting of the disease trajectory of brain ischemia-induced vascular cognitive impairment.

PubMed

Liu, Lin; Huo, Ju; Zhao, Ying; Tian, Yu

2012-03-25

The present study investigated the disease trajectory of vascular cognitive impairment using the entropy of information in a neural network mathematical simulation based on the free radical and excitatory amino acids theories. Glutamate, malondialdehyde, and inducible nitric oxide synthase content was significantly elevated, but acetylcholine, catalase, superoxide dismutase, glutathione peroxidase and constitutive nitric oxide synthase content was significantly decreased in our vascular cognitive impairment model. The fitting curves for each factor were obtained using Matlab software. Nineteen, 30 and 49 days post ischemia were the main output time frames of the influence of these seven factors. Our results demonstrated that vascular cognitive impairment involves multiple factors. These factors include excitatory amino acid toxicity and nitric oxide toxicity. These toxicities disrupt the dynamic equilibrium of the production and removal of oxygen free radicals after cerebral ischemia, reducing the ability to clear oxygen free radicals and worsening brain injury.

A Sequential Leach Method and Pb Isotope Approach to Studying Apatite Weathering in Granitoid Soils at Hubbard Brook Experimental Forest, NH, USA

NASA Astrophysics Data System (ADS)

Nezat, C. A.; Blum, J. D.

2005-12-01

Easily dissolved minerals such as calcite and apatite can be important in controlling stream and ground water chemistry even though these minerals are only present in trace amounts in granitoid rocks. Because of its solubility, apatite, a calcium phosphate mineral, may be a significant source of essential nutrients (especially phosphorous) for vegetation, and has been shown to strongly influence stream and soil water composition (e.g, calcium, strontium and rare earth elements). There are additional sources of Ca (e.g., feldspars, hornblende) and P (e.g., organic matter or bound to Fe and Al oxides) in granitoid soils. In order to distinguish the chemical constituents of apatite from other pools in the bulk soil, we selectively dissolved apatite with a dilute acid leach, and measured Pb isotopic ratios of apatite, feldspar, and leachates. We tested the leaching procedure on mineral separates and verified that a dilute nitric solution primarily dissolves apatite. Silicates were dissolved in subsequent steps by successively stronger acids. We then applied this method to bulk soils collected from several soil pits across a small watershed at the Hubbard Brook Experimental Forest (HBEF), New Hampshire, USA, to determine the spatial distribution of Ca and P pools, and determine the depth of apatite depletion in the soil. We also measured Pb isotope ratios in the soil leachates to distinguish among the various sources of Pb (e.g., apatite, feldspars and anthropogenic sources). We found that Pb in the dilute nitric leach of the HBEF organic soils is dominated by anthropogenic sources and that Pb from apatite becomes increasingly important with depth.

Synthesis of cross-linked chitosan modified with the glycine moiety for the collection/concentration of bismuth in aquatic samples for ICP-MS determination.

PubMed

Oshita, Koji; Noguchi, Osamu; Oshima, Mitsuko; Motomizu, Shoji

2007-10-01

A chelating resin, cross-linked chitosan modified with the glycine moiety (glycine-type chitosan resin), was developed for the collection and concentration of bismuth in aquatic samples for ICP-MS measurements. The adsorption behavior of bismuth and 55 elements on glycine-type chitosan resin was systematically examined by passing a sample solution containing 56 elements through a mini-column packed with the resin (wet volume; 1 ml). After eluting the elements adsorbed on the resin with nitric acid, the eluates were measured by ICP-MS. The glycine-type chitosan resin could adsorb several cations by a chelating mechanism and several oxoanions by an anion-exchange mechanism. Especially, the resin could adsorb almost 100% Bi(III) over a wide pH region from pH 2 to 6. Bismuth could be strongly adsorbed at pH 3, and eluted quantitatively with 10 ml of 3 M nitric acid. A column pretreatment method with the glycine-type chitosan resin was used prior to removal of high concentrations of matrices in a seawater sample and the preconcentration of trace bismuth in river water samples for ICP-MS measurements. The column pretreatment method was also applied to the determination of bismuth in real samples by ICP-MS. The LOD of bismuth was 0.1 pg ml(-1) by 10-fold column preconcentration for ICP-MS measurements. The analytical results for bismuth in sea and river water samples by ICP-MS were 22.9 +/- 0.5 pg ml(-1) (RSD, 2.2%) and 2.08 +/- 0.05 pg ml(-1) (RSD, 2.4%), respectively.

Evidence for a link between atmospheric thermonuclear detonations and nitric acid.

PubMed

Holdsworth, G

1986-12-11

Suitably located glacier cores, obtained from high-altitude, low-temperature sites, can reveal detailed information about atmospheric air chemistry at sub-annual resolution 1 . Such data may provide input to climate-change models, the study of acid precipitation patterns and many other phenomena. Here I present data from an ice core which show that during the era of intense atmospheric thermonuclear weapons testing (ATWT) a significant part of the nitrate content in the snow was modulated by the intensity of the nuclear detonations. The fixation of nitrogen by nuclear fireballs leads to NO x gases in the atmosphere 2 and ultimately to nitric acid in precipitation. At certain concentrations, these gases and the associated aerosols may perturb the climate 3,4 .

Inhibition of the gap junctional component of endothelium-dependent relaxations in rabbit iliac artery by 18-α glycyrrhetinic acid

PubMed Central

Taylor, Hannah J; Chaytor, Andrew T; Evans, W Howard; Griffith, Tudor M

1998-01-01

The gap junction inhibitor 18-α-glycyrrhetinic acid (α-GA, 100 μM) attenuated endothelium-dependent relaxations to acetylcholine and cyclopiazonic acid by ∼20% in rings of pre-constricted rabbit iliac artery. The nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME, 300 μM) inhibited relaxations to both agents by ∼65% and these were further attenuated by α-GA to <10% of control. In endothelium-denuded preparations, relaxations to sodium nitroprusside were not affected by α-GA. Heterocellular gap junctional communication may therefore account for nitric oxide-independent relaxations evoked both by receptor-dependent and -independent mechanisms in rabbit iliac artery. PMID:9776336

Electrochemical oxidation of 243Am(III) in nitric acid by a terpyridyl-derivatized electrode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dares, C. J.; Lapides, A. M.; Mincher, B. J.

A high surface area, tin-doped indium oxide electrode surface-derivatized with a terpyridine ligand has been applied to the oxidation of trivalent americium to Am(V) and Am(VI) in nitric acid. Potentials as low as 1.8 V vs. the saturated calomel electrode are used, 0.7 V lower than the 2.6 V potential for one-electron oxidation of Am(III) to Am(IV) in 1 M acid. This simple electrochemical procedure provides, for the first time, a method for accessing the higher oxidation states of Am in non-complexing media for developing the coordination chemistries of Am(V) and Am(VI) and, more importantly, for separation of americium frommore » nuclear waste streams.« less