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Sample records for ammonium polyuranate precipitation

  1. Influence of carbamide content in nitric acid solutions of uranium on ammoniac precipitation of ammonium polyuranates

    International Nuclear Information System (INIS)

    Balakhonov, V.G.; Dorda, F.A.; Zagumennov, V.S.; Lazarchuk, V.V.; Ledovskikh, A.K.; Matyukha, V.A.; Portnyagina, Eh.O.; Tinin, V.V.

    2004-01-01

    Regularities of ammoniac precipitation of ammonium polyuranates from nitric acid solutions of uranium in the presence of carbamide are investigated. Influence of temperature, carbamide and uranium concentration in initial solution on sedimentation and filtration properties of precipitates is determined. Optimal regimes of operations of ammoniac precipitation of ammonium polyuranates containing carbamide providing preparation of crystalline, effectively filtered precipitates are selected [ru

  2. Precipitation kinetics of a continuous precipitator, with application to the precipitation of ammonium polyuranate

    International Nuclear Information System (INIS)

    Hoyt, R.C.

    1978-04-01

    A mathematical model describing the kinetics of continuous precipitation was developed which accounts for crystal nucleation, crystal growth, primary coagulation, and secondary coagulation. Population density distributions, average particle sizes, dominant particle sizes, and suspension density fractions of the crystallites, primary agglomerates, and secondary agglomerates leaving the continuous precipitator can be determined. This kinetic model was applied to the continuous precipitation of ammonium polyuranate, which consists of: (1) elementary crystals, (2) clusters or primary coagulated particles, and (3) agglomerates or secondary coagulated particles. The crystallites are thin, submicron, hexagonal platelets. The clusters had an upper size limit of about 7 μ in diameter and contained numerous small voids (less than 0.3 μm) due to the packing of the crystallites. The agglomerates had an upper size limit of about 40 μm in diameter and contained large voids (approximately 1 μm). The particle size distribution and particle structure of the ammonium polyuranate precipitate can be controlled through proper regulation of the precipitation conditions. The ratio of clusters to agglomerates can be best controlled through the uranium concentration, and the cohesiveness or internal bonding strength of the particles can be controlled with the ammonium to uranium reacting feed mole ratio. These two conditions, in conjunction with the residence time, will determine the nucleation rates, growth rates, and size distributions of the particles leaving the continuous precipitator. With proper control of these physical particle characteristics, the use of pore formers, ball-milling, and powder blending can probably be eliminated from the nuclear fuel fabrication process, substantially reducing the cost

  3. Precipitation kinetics of a continuous precipitator, with application to the precipitation of ammonium polyuranate

    Energy Technology Data Exchange (ETDEWEB)

    Hoyt, R.C.

    1978-04-01

    A mathematical model describing the kinetics of continuous precipitation was developed which accounts for crystal nucleation, crystal growth, primary coagulation, and secondary coagulation. Population density distributions, average particle sizes, dominant particle sizes, and suspension density fractions of the crystallites, primary agglomerates, and secondary agglomerates leaving the continuous precipitator can be determined. This kinetic model was applied to the continuous precipitation of ammonium polyuranate, which consists of: (1) elementary crystals, (2) clusters or primary coagulated particles, and (3) agglomerates or secondary coagulated particles. The crystallites are thin, submicron, hexagonal platelets. The clusters had an upper size limit of about 7 ..mu.. in diameter and contained numerous small voids (less than 0.3 ..mu..m) due to the packing of the crystallites. The agglomerates had an upper size limit of about 40 ..mu..m in diameter and contained large voids (approximately 1 ..mu..m). The particle size distribution and particle structure of the ammonium polyuranate precipitate can be controlled through proper regulation of the precipitation conditions. The ratio of clusters to agglomerates can be best controlled through the uranium concentration, and the cohesiveness or internal bonding strength of the particles can be controlled with the ammonium to uranium reacting feed mole ratio. These two conditions, in conjunction with the residence time, will determine the nucleation rates, growth rates, and size distributions of the particles leaving the continuous precipitator. With proper control of these physical particle characteristics, the use of pore formers, ball-milling, and powder blending can probably be eliminated from the nuclear fuel fabrication process, substantially reducing the cost.

  4. Protein Precipitation Using Ammonium Sulfate

    OpenAIRE

    Wingfield, Paul T.

    2001-01-01

    The basic theory of protein precipitation by addition of ammonium sulfate is presented and the most common applications are listed, Tables are provided for calculating the appropriate amount of ammonium sulfate to add to a particular protein solution.

  5. Protein Precipitation Using Ammonium Sulfate.

    Science.gov (United States)

    2016-04-01

    The basic theory of protein precipitation by addition of ammonium sulfate is presented, and the most common applications are listed. Tables are provided for calculating the appropriate amount of ammonium sulfate to add to a particular protein solution. Copyright © 2016 John Wiley & Sons, Inc.

  6. Control of particle size distribution and agglomeration in continuous ammonium polyuranate precipitation

    International Nuclear Information System (INIS)

    Hoyt, R.C.; Burkhart, L.

    1978-01-01

    The results are summarized of the first step in a program to develop a scientific basis for preparing powders with reproducible properties which can be predicted from process operating conditions and can be varied in a systematic fashion to facilitate research in sintering operations and to provide a reliable means of large-scale production with a minimum amount of pellets rejected

  7. Study on effect of precipitation conditions on the properties of ammonium diuranate

    International Nuclear Information System (INIS)

    Kraikaew, J.; Yacumpai, O.; Pruantonsai, P.

    1994-01-01

    This study was carried out in order to select the optimum conditions for ammonium diuranate (ADU) precipitation to obtain high density uranium dioxide. The data were collected for ADU precipitation reactor design. The precipitation temperature was controlled at 50 0 C. The stirrer speeds are 5.9 and 7.1 Hz. The properties namely : specific filtration resistance, initial settling rate and agglomerate size of ADU precipitates obtained at various pH were investigated. The results indicated that when the pH of precipitation increases, specific filtration resistance increases but ADU agglomerate size decreases and causing difficulty in filtration

  8. Improved daily precipitation nitrate and ammonium concentration models for the Chesapeake Bay Watershed

    Energy Technology Data Exchange (ETDEWEB)

    Grimm, J.W. [Institutes of the Environment, Pennsylvania State University, University Park, PA 16802 (United States); Lynch, J.A. [School of Forest Resources, Pennsylvania State University, 311 Forest Resources Lab, University Park, PA 16802 (United States)]. E-mail: jal@psu.edu

    2005-06-15

    Daily precipitation nitrate and ammonium concentration models were developed for the Chesapeake Bay Watershed (USA) using a linear least-squares regression approach and precipitation chemistry data from 29 National Atmospheric Deposition Program/National Trends Network (NADP/NTN) sites. Only weekly samples that comprised a single precipitation event were used in model development. The most significant variables in both ammonium and nitrate models included: precipitation volume, the number of days since the last event, a measure of seasonality, latitude, and the proportion of land within 8 km covered by forest or devoted to industry and transportation. Additional variables included in the nitrate model were the proportion of land within 0.8 km covered by water and/or forest. Local and regional ammonia and nitrogen oxide emissions were not as well correlated as land cover. Modeled concentrations compared very well with event chemistry data collected at six NADP/AirMoN sites within the Chesapeake Bay Watershed. Wet deposition estimates were also consistent with observed deposition at selected sites. Accurately describing the spatial distribution of precipitation volume throughout the watershed is important in providing critical estimates of wet-fall deposition of ammonium and nitrate. - A linear least-squares regression approach was used to develop daily precipitation nitrate and ammonium concentration models for the Chesapeake Bay Watershed.

  9. Improved daily precipitation nitrate and ammonium concentration models for the Chesapeake Bay Watershed.

    Science.gov (United States)

    Grimm, J W; Lynch, J A

    2005-06-01

    Daily precipitation nitrate and ammonium concentration models were developed for the Chesapeake Bay Watershed (USA) using a linear least-squares regression approach and precipitation chemistry data from 29 National Atmospheric Deposition Program/National Trends Network (NADP/NTN) sites. Only weekly samples that comprised a single precipitation event were used in model development. The most significant variables in both ammonium and nitrate models included: precipitation volume, the number of days since the last event, a measure of seasonality, latitude, and the proportion of land within 8km covered by forest or devoted to industry and transportation. Additional variables included in the nitrate model were the proportion of land within 0.8km covered by water and/or forest. Local and regional ammonia and nitrogen oxide emissions were not as well correlated as land cover. Modeled concentrations compared very well with event chemistry data collected at six NADP/AirMoN sites within the Chesapeake Bay Watershed. Wet deposition estimates were also consistent with observed deposition at selected sites. Accurately describing the spatial distribution of precipitation volume throughout the watershed is important in providing critical estimates of wet-fall deposition of ammonium and nitrate.

  10. Optimization of tetanus toxoid ammonium sulfate precipitation process using response surface methodology.

    Science.gov (United States)

    Brgles, Marija; Prebeg, Pero; Kurtović, Tihana; Ranić, Jelena; Marchetti-Deschmann, Martina; Allmaier, Günter; Halassy, Beata

    2016-10-02

    Tetanus toxoid (TTd) is a highly immunogenic, detoxified form of tetanus toxin, a causative agent of tetanus disease, produced by Clostridium tetani. Since tetanus disease cannot be eradicated but is easily prevented by vaccination, the need for the tetanus vaccine is permanent. The aim of this work was to investigate the possibility of optimizing TTd purification, i.e., ammonium sulfate precipitation process. The influence of the percentage of ammonium sulfate, starting amount of TTd, buffer type, pH, temperature, and starting purity of TTd on the purification process were investigated using optimal design for response surface models. Responses measured for evaluation of the ammonium sulfate precipitation process were TTd amount (Lf/mL) and total protein content. These two parameters were used to calculate purity (Lf/mgPN) and the yield of the process. Results indicate that citrate buffer, lower temperature, and lower starting amount of TTd result in higher purities of precipitates. Gel electrophoresis combined with matrix-assisted laser desorption ionization-mass spectrometric analysis of precipitates revealed that there are no inter-protein cross-links and that all contaminating proteins have pIs similar to TTd, so this is most probably the reason for the limited success of purification by precipitation.

  11. A new technique for the synthesis of ammonium phosphomolybdate: precipitation in resin support

    International Nuclear Information System (INIS)

    Matsuda, H.T.

    1977-01-01

    A technique for synthesizing ammonium molybdophosphate, an inorganic ion exchanger which retains selectively cesium-137 from a mixture of fission products, employing a strong anionic resin, saturated with molybdate anions, is presented. This method enables the precipitation of ammonium molybdophosphate directly into the resinous structure by adding dihydrogen ammonium phosphate in 7,5M HNO 3 . The reactants maintened at 60 0 C for a period of four hours has been found to be the optimum condition for a maximum yield of this compound (anionic resin-ammonium molybdophosphate = R-AMP). The tests performed for characterizing this compound are: molybdenum-phosphorus ratio determination, electronic absorption spectra, infra-red absorption spectra, reflection microscopy observations, electron probe micro-analysis and X-ray powder patterns. The analysis confirmed the presence of the ammonium molybdophosphate in the resinous structure, permitting, thereby, its use as a cation exchanger. R-AMP showed a capacity of 0,48mE/g of dry material. The cesium retention studies were made using columns charged with R-AMP compound. The behavior of polivalent fission products was studied. The R-AMP column was applied to separate cesium from irradiated uranium solutions [pt

  12. Tetanus toxoid purification: chromatographic procedures as an alternative to ammonium-sulphate precipitation.

    Science.gov (United States)

    Stojićević, Ivana; Dimitrijević, Ljiljana; Dovezenski, Nebojša; Živković, Irena; Petrušić, Vladimir; Marinković, Emilija; Inić-Kanada, Aleksandra; Stojanović, Marijana

    2011-08-01

    Given an existing demand to establish a process of tetanus vaccine production in a way that allows its complete validation and standardization, this paper focuses on tetanus toxoid purification step. More precisely, we were looking at a possibility to replace the widely used ammonium-sulphate precipitation by a chromatographic method. Based on the tetanus toxin's biochemical characteristics, we have decided to examine the possibility of tetanus toxoid purification by hydrophobic chromatography, and by chromatographic techniques based on interaction with immobilized metal ions, i.e. chelating chromatography and immobilized metal affinity chromatography. We used samples obtained from differently fragmented crude tetanus toxins by formaldehyde treatment (assigned as TTd-A and TTd-B) as starting material for tetanus toxoid purification. Obtained results imply that purification of tetanus toxoid by hydrophobic chromatography represents a good alternative to ammonium-sulphate precipitation. Tetanus toxoid preparations obtained by hydrophobic chromatography were similar to those obtained by ammonium-sulphate precipitation in respect to yield, purity and immunogenicity. In addition, their immunogenicity was similar to standard tetanus toxoid preparation (NIBSC, Potters Bar, UK). Furthermore, the characteristics of crude tetanus toxin preparations had the lowest impact on the final purification product when hydrophobic chromatography was the applied method of tetanus toxoid purification. On the other hand, purifications of tetanus toxoid by chelating chromatography or immobilized metal affinity chromatography generally resulted in a very low yield due to not satisfactory tetanus toxoid binding to the column, and immunogenicity of the obtained tetanus toxoid-containing preparations was poor. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Nucleation and growth kinetics of zirconium hydroxide by precipitation with ammonium hydroxide

    International Nuclear Information System (INIS)

    Carleson, T.E.; Chipman, N.A.

    1987-01-01

    The results of a study of the nucleation and growth kinetics of the precipitation of zirconium hydroxide from the reaction of hexafluorozirconate solution with ammonium hydroxide are reported. The McCabe linear growth rate model was used to correlate the results. The growth rate decreased with residence time and supersaturation for studies with 7 residence times (3.5 - 90 minutes and two supersaturation ratios (0.03 - 0.04, and 0.4). The nucleation rate increased with residence time and supersaturation. A negative kinetic order of nucleation was observed that may be due to the inhibition of particle growth by adsorption of reacting species on the crystal surfaces

  14. Changes of pH during biomacromolecule crystallization by vapor diffusion using ammonium sulfate as the precipitant

    International Nuclear Information System (INIS)

    Mikol, V.; Giege, R.; Rodeau, J.L.

    1989-01-01

    Possible pH variations during crystallization of biological macromolecules by the vapor diffusion method have not been taken into account in most experiments so far reported. The present study demonstrates that when ammonium sulfate is used as the precipitant, pH changes occur due to ammonia transfer following ammonium/ammonia equilibrium. The pH in a crystallization droplet is shown to be controlled by that of the reservoir. The theory of the effect is given and the consequences of pH variations during crystallization are discussed in terms of reproducibility of experiments. An application, the crystallization of concanavalin A induced by pH variation, is presented. (orig.)

  15. Combination of the method of basic precipitation of lanthanons with the ion exchange distribution method by means of ammonium acetate

    International Nuclear Information System (INIS)

    Hubicki, W.; Hubicka, H.

    1980-01-01

    The method of basic precipitation of lanthanons was combined with the ion exchange distribution method using ammonium acetate. As a result of chromatogram development 1:2 the good results of distribution of Sm -Nd, the fractions 99,9% Nd 2 O 3 and Pr 6 O 11 and 99,5% La 2 O 3 were obtained. It was found that the way of packing the column influenced greatly the efficiency of ion distribution. (author)

  16. U3O8 and UO2 obtained from ADU (ammonium diuranate) ultrasonically treated

    International Nuclear Information System (INIS)

    Boero, N.; Sassone, A.; Mendez de Leo, L.; Novara, O.; Ramella, J.

    1996-01-01

    At present, obtention of U 3 O 8 used in the manufacturing of MTR plates nuclear fuels, is performed by hydrolysis of UF6 to obtain uranyl fluoride. Uranyl fluoride is precipitated with ammonium hydroxide to get ammonium polyuranate (ADU). Afterwards ADU is calcinated to U 3 O 8 and mechanical and thermally treated in order to obtain a powder in a determined specification. In the present work, ultrasound has been applied in the stage of precipitation of ADU and for different times in the stage of digestion in order to fasten the stages of ADU filtering and eliminate the U 3 O 8 milling and sieving. Experiences on UO 2 have also been performed. The aspect of ADU changes considerably when they have been ultrasonically treated, its filtering rate is faster and it is easier to dry as it contains less humidity. U 3 O 8 obtained after 800degreeC calcination of treated ADU results in an easy to desagregate powder. Only a soft mechanical treatment is needed to be performed on it before starting thermal treatment at 1400degreeC. After thermal treatment at 1400degreeC treated U 3 O 8 has shown adequate characteristics of size, shape and density (8.2 g/cm 3 ). Regarding UO 2 , the shape of the agglomerates is almost spherical, leading to a free-flowing powder, whose apparent and TAP density showed to be adequate. The characteristics of the different compounds were followed by electron scanning micrographies, X-Rays, specific area measurements and differential thermal analysis. The great advantage of ultrasound appliance is that hard mechanical treatment is avoided in the obtention of U 3 O 8 , saving time and effort. Furthermore, UO 2 proves to be adequate to make pellets, the same precursor could be used in the obtention of both uranium oxides. (author). 5 refs., 6 figs

  17. Recovery and purification of limonin from pummelo [Citrus grandis] peel using water extraction, ammonium sulfate precipitation and resin adsorption.

    Science.gov (United States)

    Yang, Yuan Fan; Zhang, Liang Zheng; Du, Xi Ping; Zhang, Su Fang; Li, Li Jun; Jiang, Ze Dong; Wu, Li Ming; Ni, Hui; Chen, Feng

    2017-08-15

    Limonin is a bioactive compound that is traditionally extracted from citrus seeds using organic solvents or alkaline/metal ion solutions. In the present study, pummelo [Citrus grandis] peel was investigated for limonin preparation using a novel process consisting of water extraction, ammonium sulfate precipitation and resin adsorption. The pummelo peel was determined to have 4.7mg/g limonin, which could be extracted by water and further recovered by ammonium sulfate precipitation with a yield of 2.4mg/g, which was similar to that of traditional process using ethanol extraction and vacuumed evaporation. The precipitated limonin was purified by resin adsorption and crystallization with a purity of 96.4%. In addition, the limonin was identified via the analyses of retention time, infrared spectrum and nuclear magnetic resonance. This study indicates a novel and eco-friendly process for recovering limonin, providing a new candidate for limonin preparation. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Study of precipitation kinetics of vanadium compounds from the solutions of ammonium sulfate

    International Nuclear Information System (INIS)

    Fofarov, A.A.; Sukhov, A.A.; Batrakova, L.Kh.; Ostashko, T.I.

    1988-01-01

    To select the regime of vanadium deposition from ammonium sulfate solutions the dependence of deposition rate on the concentration of reacting components and conditions of the process course. The maximum deposition rate of vanadium compounds proved to be at pH 2.0-2.2. With an increase in ammonium sulfate content from 0 to 80-100 g/dm 3 the deposition rate decreases by a factor of 2. With an increase in the temperature by each 10 deg C in the temperature range of 70-90 deg C vanadium deposition rate at the same supersaturation increases by a factor of 1.72. Kinetic equation of vanadium deposition in the presence of 80 g/dm 3 ammonium sulfate is obtained

  19. Growth kinetics for the precipitation of zirconium hydroxide from aqueous zirconium and tin bearing solutions by the addition of ammonium hydroxide

    Energy Technology Data Exchange (ETDEWEB)

    Carleson, T.E. [Idaho Univ., Moscow, ID (United States). Dept. of Chemical Engineering; Chipman, N.A. [Westinghouse Idaho Nuclear Co., Inc., Idaho Falls, ID (United States)

    1989-09-11

    The precipitation of zirconium hydroxide from an aqueous solution of ammonium hexafluorozirconate occurs rapidly upon addition of ammonium hydroxide. Experimental data indicate growth and nucleation rates between 0.06 and 0.28 microns/minute and around 10 {times} 107 number/L-min, respectively. Experiments with a mixed suspension mixed product removal crystallizer for concentrations of reactants of about 0.05 M ammonium hexafluorozirconate precipitating with 0.002 M ammonium hydroxide showed apparent nonlinear growth rates in some cases but not others. Batch studies indicated that growth rate dispersion is probably not present. When the AFL nonlinear model was used to fit the data, the power coefficient obtained was greater than 1, in disagreement with theory. In addition, for some of the data ``S`` shaped curves of the logarithm of the cumulative number greater than versus size were obtained. These curves can not be fit by the AFL model. A program developed at the University of Arizona was used to simulate the crystallization runs. The program results indicated that some of the nonlinear behavior may be attributed to transient conditions. Experimental data also illustrated this behavior. The effect of trace amounts of tin fluoride (0.008 M) on the nucleation and growth kinetics was also evaluated. For some residence times, the presence of tin resulted in reduced median particle diameters, higher growth rates, and lower number counts.

  20. Study of the changes in composition of ammonium diuranate with progress of precipitation, and study of the properties of ammonium diuranate and its subsequent products produced from both uranyl nitrate and uranyl fluoride solutions

    Energy Technology Data Exchange (ETDEWEB)

    Manna, Subhankar; Kumar, Raj; Satpati, Santosh K.; Roy, Saswati B. [Bhabha Atomic Research Centre, Trombay, Mumbai (India); Joshi, Jyeshtharaj B. [Dept. of Chemical Engineering, Institute of Chemical Technology, Mumbai (India)

    2017-04-15

    Uranium metal used for fabrication of fuel for research reactors in India is generally produced by magnesio-thermic reduction of UF{sub 4}. Performance of magnesio-thermic reaction and recovery and quality of uranium largely depends on properties of UF{sub 4}. As ammonium diuranate (ADU) is first product in powder form in the process flow-sheet, properties of UF{sub 4} depend on properties of ADU. ADU is generally produced from uranyl nitrate solution (UNS) for natural uranium metal production and from uranyl fluoride solution (UFS) for low enriched uranium metal production. In present paper, ADU has been produced via both the routes. Variation of uranium recovery and crystal structure and composition of ADU with progress in precipitation reaction has been studied with special attention on first appearance of the precipitate Further, ADU produced by two routes have been calcined to UO{sub 3}, then reduced to UO{sub 2} and hydroflorinated to UF{sub 4}. Effect of two different process routes of ADU precipitation on the characteristics of ADU, UO{sub 3}, UO{sub 2} and UF{sub 4} were studied here.

  1. Study of the changes in composition of ammonium diuranate with progress of precipitation, and study of the properties of ammonium diuranate and its subsequent products produced from both uranyl nitrate and uranyl fluoride solutions

    International Nuclear Information System (INIS)

    Manna, Subhankar; Kumar, Raj; Satpati, Santosh K.; Roy, Saswati B.; Joshi, Jyeshtharaj B.

    2017-01-01

    Uranium metal used for fabrication of fuel for research reactors in India is generally produced by magnesio-thermic reduction of UF 4 . Performance of magnesio-thermic reaction and recovery and quality of uranium largely depends on properties of UF 4 . As ammonium diuranate (ADU) is first product in powder form in the process flow-sheet, properties of UF 4 depend on properties of ADU. ADU is generally produced from uranyl nitrate solution (UNS) for natural uranium metal production and from uranyl fluoride solution (UFS) for low enriched uranium metal production. In present paper, ADU has been produced via both the routes. Variation of uranium recovery and crystal structure and composition of ADU with progress in precipitation reaction has been studied with special attention on first appearance of the precipitate Further, ADU produced by two routes have been calcined to UO 3 , then reduced to UO 2 and hydroflorinated to UF 4 . Effect of two different process routes of ADU precipitation on the characteristics of ADU, UO 3 , UO 2 and UF 4 were studied here

  2. Study of the Changes in Composition of Ammonium Diuranate with Progress of Precipitation, and Study of the Properties of Ammonium Diuranate and its Subsequent Products Produced from both Uranyl Nitrate and Uranyl Fluoride Solutions

    Directory of Open Access Journals (Sweden)

    Subhankar Manna

    2017-04-01

    Full Text Available Uranium metal used for fabrication of fuel for research reactors in India is generally produced by magnesio-thermic reduction of UF4. Performance of magnesio-thermic reaction and recovery and quality of uranium largely depends on properties of UF4. As ammonium diuranate (ADU is first product in powder form in the process flow-sheet, properties of UF4 depend on properties of ADU. ADU is generally produced from uranyl nitrate solution (UNS for natural uranium metal production and from uranyl fluoride solution (UFS for low enriched uranium metal production. In present paper, ADU has been produced via both the routes. Variation of uranium recovery and crystal structure and composition of ADU with progress in precipitation reaction has been studied with special attention on first appearance of the precipitate Further, ADU produced by two routes have been calcined to UO3, then reduced to UO2 and hydroflorinated to UF4. Effect of two different process routes of ADU precipitation on the characteristics of ADU, UO3, UO2 and UF4 were studied here.

  3. Superconducting and mechanical properties of the bulk Bi(pb)SCCO system prepared via solid state and ammonium nitrate precipitation methods

    Energy Technology Data Exchange (ETDEWEB)

    Safran, S., E-mail: safran@science.ankara.edu.tr [Ankara University, Faculty of Science, Department of Physics, Tandoğan, Ankara 06100 (Turkey); Center of Excellence for Superconductivity Research, 50 Year Campus, Golbaşı, Ankara (Turkey); Kılıçarslan, E.; Ozturk, H. [Ankara University, Faculty of Science, Department of Physics, Tandoğan, Ankara 06100 (Turkey); Center of Excellence for Superconductivity Research, 50 Year Campus, Golbaşı, Ankara (Turkey); Alp, M. [Center of Excellence for Superconductivity Research, 50 Year Campus, Golbaşı, Ankara (Turkey); Akdogan, M. [Center of Excellence for Superconductivity Research, 50 Year Campus, Golbaşı, Ankara (Turkey); Abant İzzet Baysal University, Department of Physics, Bolu (Turkey); Asikuzun, E.; Ozturk, O. [Kastamonu University, Department of Physics, Kastamonu (Turkey); Kastamonu University, Research and Application Center, Kastamonu (Turkey); Kılıç, A. [Ankara University, Faculty of Science, Department of Physics, Tandoğan, Ankara 06100 (Turkey); Center of Excellence for Superconductivity Research, 50 Year Campus, Golbaşı, Ankara (Turkey)

    2015-09-01

    We have investigated the effect of preparation method on superconducting and mechanical properties of Bi(Pb)-2223 bulk samples using Bi{sub 1.85}Pb{sub 0.35}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10±y} stoichiometry. Solid-state reaction and ammonium nitrate precipitation methods have been used for fabrication of the bulk samples. In addition, the effect of annealing time on BSCCO samples have been studied. Structural, electrical, magnetic and microhardness analyses of samples are performed by the X-ray powder diffraction (XRD), the Scanning Electron Microscopy (SEM), DC resistivity, AC susceptibility and Vickers microhardness test. The critical transition temperature, phase purity, surface morphology and crystallinity of the prepared bulk samples are compared with each other. Elasticity (E), brittleness (B{sub i}), fracture toughness (K{sub IC}) and yield strength (Y) values are also determined according to annealing time, applied load and production parameters of materials.

  4. Characterization of alumina obtained from the synthesis of gelatinous precipitates of aluminum hydroxide obtained from the reaction of aluminum sulfate and ammonium hydroxide in different temperatures

    International Nuclear Information System (INIS)

    Mercury, Jose Manuel Rivas; Freitas Neves, R. de

    1996-01-01

    Aluminum hydroxide was obtained by synthesis through neutralization of solutions aluminum sulphate solutions with ammonium hydroxide at different level of temperatures of synthesis (30, 60, 90 deg C) on the molar [OH]/[Al +3 ] of 6,5. All products was burned at 950 deg C during two hours of dried aluminum hydroxide powder. Alumina obtained and A-16SG, APC-2011, produced by Alcoa Co. was characterized by Bulk Density, Tap density, Real Density, Particle Size Distribution, X-Ray Diffractions and Chemical Analysis and both compared. (author)

  5. Isolation and stable nitrogen isotope analysis of ammonium ions in ammonium nitrate prills using sodium tetraphenylborate.

    Science.gov (United States)

    Howa, John D; Lott, Michael J; Ehleringer, James R

    2014-07-15

    Because of the threat of bombings using improvised explosives containing ammonium nitrate (AN), law enforcement and intelligence communities have been interested in stable isotope techniques for tracking and discriminating AN sources. Separate analysis of the AN component ions ammonium and nitrate would add discriminatory power to these techniques. Ammonium ions in dissolved AN solution were isolated from samples by precipitation using sodium tetraphenylborate solution. We tested the isolation of ammonium from nitrates using solutions of ammonium and nitrate salts with different (15)N/(14)N isotope ratios. Ammonium tetraphenylborate and AN were separately analyzed for their (15)N/(14)N isotope ratios using EA-ConFlo-IRMS, and the (15)N/(14)N isotope ratios of the nitrate ions were calculated using mass balance. Ammonium and nitrate nitrogen isotope ratios were plotted as two separate variables. Isolation of ammonium precipitate from solutions containing dissolved nitrates did not influence the nitrogen isotope ratios of test ammonium salts. A survey set of 42 AN samples showed that the ammonium and nitrate (15)N/(14)N isotope ratios were not significantly correlated, and the paired mean differences were not statistically significant. Both ammonium and nitrate were depleted in (15)N relative to their theoretical atmospheric sources. Isolation of the ammonium ion from AN adds another dimension for the discrimination of forensic AN samples. This technique using sodium tetraphenylborate is robust and does not require specialized equipment. Our observations indicated that ammonium nitrogen and nitrate nitrogen have independent sources of isotopic variation. Copyright © 2014 John Wiley & Sons, Ltd.

  6. Producing ammonium uranate in spherical particulate form

    International Nuclear Information System (INIS)

    Dugua, J.

    1984-01-01

    A novel easily handled substantially particulate ammonium uranate with a mean diameter between 30 and 150 micrometers, an apparent untamped bulk density of 2 to 2.8 g/cm 3 , and a flowability measured on the Carr scale equal to or greater than 95, with a low sulfate ion content between 0.5 and 1%, is calimed together with a fluidized bed process for preparing such ammonium uranate by precipitation of a super-saturated solution of ammonium uranate. The ammonium uranate is obtained by reacting a uranium sulfate solution and an ammoniacal solution, operating at a pH of about 6.6 to 7.2

  7. Validation of a Rapid and Sensitive UPLC-MS-MS Method Coupled with Protein Precipitation for the Simultaneous Determination of Seven Pyrethroids in 100 µL of Rat Plasma by Using Ammonium Adduct as Precursor Ion.

    Science.gov (United States)

    Singh, Sheelendra Pratap; Dwivedi, Nistha; Raju, Kanumuri Siva Rama; Taneja, Isha; Wahajuddin, Mohammad

    2016-04-01

    United States Environmental Protection Agency has recommended estimating pyrethroids' risk using cumulative exposure. For cumulative risk assessment, it would be useful to have a bioanalytical method for quantification of one or several pyrethroids simultaneously in a small sample volume to support toxicokinetic studies. Therefore, in the present study, a simple, sensitive and high-throughput ultraperformance liquid chromatography-tandem mass spectrometry method was developed and validated for simultaneous analysis of seven pyrethroids (fenvalerate, fenpropathrin, bifenthrin, lambda-cyhalothrin, cyfluthrin, cypermethrin and deltamethrin) in 100 µL of rat plasma. A simple single-step protein precipitation method was used for the extraction of target compounds. The total chromatographic run time of the method was 5 min. The chromatographic system used a Supelco C18 column and isocratic elution with a mobile phase consisting of methanol and 5 mM ammonium formate in the ratio of 90 : 10 (v/v). Mass spectrometer (API 4000) was operated in multiple reaction monitoring positive-ion mode using the electrospray ionization technique. The calibration curves were linear in the range of 7.8-2,000 ng/mL with correlation coefficients of ≥ 0.99. All validation parameters such as precision, accuracy, recovery, matrix effect and stability met the acceptance criteria according to the regulatory guidelines. The method was successfully applied to the toxicokinetic study of cypermethrin in rats. To the best of our knowledge, this is the first LC-MS-MS method for the simultaneous analysis of pyrethroids in rat plasma. This validated method with minimal modification can also be utilized for forensic and clinical toxicological applications due to its simplicity, sensitivity and rapidity. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Validation of a Rapid and Sensitive UPLC–MS-MS Method Coupled with Protein Precipitation for the Simultaneous Determination of Seven Pyrethroids in 100 µL of Rat Plasma by Using Ammonium Adduct as Precursor Ion

    Science.gov (United States)

    Singh, Sheelendra Pratap; Dwivedi, Nistha; Raju, Kanumuri Siva Rama; Taneja, Isha; Wahajuddin, Mohammad

    2016-01-01

    United States Environmental Protection Agency has recommended estimating pyrethroids’ risk using cumulative exposure. For cumulative risk assessment, it would be useful to have a bioanalytical method for quantification of one or several pyrethroids simultaneously in a small sample volume to support toxicokinetic studies. Therefore, in the present study, a simple, sensitive and high-throughput ultraperformance liquid chromatography–tandem mass spectrometry method was developed and validated for simultaneous analysis of seven pyrethroids (fenvalerate, fenpropathrin, bifenthrin, lambda-cyhalothrin, cyfluthrin, cypermethrin and deltamethrin) in 100 µL of rat plasma. A simple single-step protein precipitation method was used for the extraction of target compounds. The total chromatographic run time of the method was 5 min. The chromatographic system used a Supelco C18 column and isocratic elution with a mobile phase consisting of methanol and 5 mM ammonium formate in the ratio of 90 : 10 (v/v). Mass spectrometer (API 4000) was operated in multiple reaction monitoring positive-ion mode using the electrospray ionization technique. The calibration curves were linear in the range of 7.8–2,000 ng/mL with correlation coefficients of ≥0.99. All validation parameters such as precision, accuracy, recovery, matrix effect and stability met the acceptance criteria according to the regulatory guidelines. The method was successfully applied to the toxicokinetic study of cypermethrin in rats. To the best of our knowledge, this is the first LC–MS-MS method for the simultaneous analysis of pyrethroids in rat plasma. This validated method with minimal modification can also be utilized for forensic and clinical toxicological applications due to its simplicity, sensitivity and rapidity. PMID:26801239

  9. Novel Ammonium Metal Borohydrides

    DEFF Research Database (Denmark)

    Grinderslev, Jakob; Jepsen, Lars Haahr; Cerny, Radovan

    halide-free ammonium metal borohydrides is presented, which have the chemical compositions (NH4)xM(BH4)n+x. The ammonium metal borohydrides are synthesized by cryomilling of NH4BH4 – M(BH4)n (M = Li, Na, K, Mg, Sr, Y, Mn, La, Gd) in different ratios. A new range of ammonium metal borohydrides is formed...

  10. An immunoglobulin E assay using radiolabelled Fab' and ammonium sulfate

    International Nuclear Information System (INIS)

    Wilcsek, R.J.; Hamburger, R.N.

    1978-01-01

    An immunochemical assay is described in which a radiolabelled antibody fragment, Fab', is bound specifically to immunoglobulin E (IgE), and precipitated with ammonium sulfate. The radioactivity in the precipitate is a measure of the amount of IgE in the sample. Results for six serum samples are compared using the double antibody and ammonium sulfate methods as well as the papωr radioimmunosorbent test (PRIST)

  11. Ammonium nitrate explosion hazards

    Directory of Open Access Journals (Sweden)

    Negovanović Milanka

    2015-01-01

    Full Text Available Ammonium nitrate (AN primarily is used as a fertilizer but it is also very important compound in the production of industrial explosives. The application of ammonium nitrate in the production of industrial explosives was related with the early era of Nobel dynamite and widely increased with the appearance of blasting agents such as ANFO and Slurry, in the middle of the last Century. Throughout the world millions of tons of ammonium nitrate are produced annually and handled without incident. Although ammonium nitrate generally is used safely, accidental explosions involving AN have high impact resulting in loss of lives and destruction of property. The paper presents the basic properties of ammonium nitrate as well as hazards in handling of ammonium nitrate in order to prevent accidents. Several accidents with explosions of ammonium nitrate resulted in catastrophic consequences are listed in the paper as examples of non-compliance with prescribed procedures.

  12. Elevated ammonium levels

    DEFF Research Database (Denmark)

    Søgaard, Rikke; Novak, Ivana; MacAulay, Nanna

    2012-01-01

    Increased ammonium (NH(4)(+)/NH(3)) in the brain is a significant factor in the pathophysiology of hepatic encephalopathy, which involves altered glutamatergic neurotransmission. In glial cell cultures and brain slices, glutamate uptake either decreases or increases following acute ammonium expos...

  13. Investigation into kinetics of obtaining sodium and ammonium sulfate zirconates

    International Nuclear Information System (INIS)

    Gavrilova, R.V.; Kolenkova, M.A.; Sazhina, V.A.

    1981-01-01

    The kinetics of the process of sodium and ammonium sulfate zirconates precipitation is studied. The following optimum conditions of their separation are determined: ZrO 2 concentration in sulfate solution (with αsub(s)=2.0) is 200 g/dm 3 , the quantity of precipitator-sodium (ammonium) chloride-is 3.5 mole per 1 mole ZrO 2 , the temperature is 90 deg C, the duration of mixing is 1 hr. It is established that the process of precipitation of sulfatozirconates is within the kinetic region. The average values of activation energy constitute 40 and 50 kJ/mol for sodium and ammonium sulfate zirconates respectively [ru

  14. Gas-Liquid Precipitation of water dissolved heavy metal ions using hydrogen sulfide gas

    NARCIS (Netherlands)

    Al Tarazi, M.Y.M.

    2004-01-01

    Precipitation of solids promoted by gas-liquid reactions is applied in many industrial processes such as the production of ammonium phosphate, ammonium sulphate, barium carbonate, calcium carbonate, calcium fluoride, ypsum (calcium sulphate), goethite, sodium bicarbonate, strontium carbonate and

  15. Novel Ammonium Metal Borohydrides

    DEFF Research Database (Denmark)

    Grinderslev, Jakob; Jepsen, Lars Haahr; Cerny, Radovan

    , it cannot store hydrogen reversibly. Recently, the first ammonium metal borohydride, NH4Ca(BH4)3 was published, which may be considered as substitution of K+ by NH4+ in KCa(BH4)3, due to the similar sizes of NH4+ and K+[1]. This compound successfully stabilizes NH4BH4. In the present work, a series of novel...... halide-free ammonium metal borohydrides is presented, which have the chemical compositions (NH4)xM(BH4)n+x. The ammonium metal borohydrides are synthesized by cryomilling of NH4BH4 – M(BH4)n (M = Li, Na, K, Mg, Sr, Y, Mn, La, Gd) in different ratios. A new range of ammonium metal borohydrides is formed......, and the crystal structures and thermal decompositions are investigated. Mixtures of NH4BH4 - NaBH4 do not react, while solid solutions, K1-x(NH4)xBH4, are formed for NH4BH4 - KBH4. For the other composites, novel ammonium metal borohydrides are formed. Several of these structures have been solved from high...

  16. Chemical treatment of ammonium fluoride solution in uranium reconversion plant

    International Nuclear Information System (INIS)

    Carvalho Frajndlich, E.U. de.

    1992-01-01

    A chemical procedure is described for the treatment of the filtrate, produced from the transformation of uranium hexafluoride (U F 6 ) into ammonium uranyl carbonate (AUC). This filtrate is an intermediate product in the U F 6 to uranium dioxide (U O 2 ) reconversion process. The described procedure recovers uranium as ammonium peroxide fluoro uranate (APOFU) by precipitation with hydrogen peroxide (H 2 O 2 ), and as later step, its calcium fluoride (CaF 2 ) co-precipitation. The recovered uranium is recycled to the AUC production plant. (author)

  17. Uranium concentrate obtained from sulfuric liquor by solvent extraction using ammonium sulfate as extractant agent

    International Nuclear Information System (INIS)

    Morais, Carlos Antonio de; Gomiero, Luiz Alberto

    2005-01-01

    Results of uranium concentrate obtainment from sulfuric liquor by solvent extraction followed by chemical precipitation techniques are presented. In the extraction process a tertiary amine as extractant agent and ammonium sulfate solution as stripping agent were used. Uranium was precipitated from the pregnant strip solution as ammonium diuranate by addition of ammonium hydroxide solution. Equilibrium pH and chloride content in the loaded solvent were the main interference on the uranium stripping stage. From a chloride-free uranium loaded organic phase a pregnant strip solution containing 33.2 g/L U 3 O 8 and a stripped solvent with 0.006 g/L U 3 O 8 using 5 stages of mixer-settlers were obtained. The chemical precipitation stage yielded a high purity ammonium diuranate precipitate with a recovery of 99.98%. After calcination, the product presented 99.7 % U 3 O 8 content. (author)

  18. Precipitation of uranium concentrates by hydrogen peroxide

    International Nuclear Information System (INIS)

    Barbosa Filho, O.; Teixeira, L.A.C.

    1987-01-01

    An experimental study on the precipitation of uranyl peroxide (UO 4 x H 2 O) has been carried out in a laboratory scale. The objective was to assess the possibility of the peroxide route as an alternative to a conventional ammonium diuranate process. A factorial design was used to evaluate the effects of the initial pH, precipitation pH and H 2 O 2 /UO 2 2+ ratio upon the process. The responses were measured in terms of: efficiency of U precipitation, content of U in the precipitates, and distribution of impurities in the precipitates. (Author) [pt

  19. Heterogeneous reactions of alkylamines with ammonium sulfate and ammonium bisulfate.

    Science.gov (United States)

    Qiu, Chong; Wang, Lin; Lal, Vinita; Khalizov, Alexei F; Zhang, Renyi

    2011-06-01

    The heterogeneous reactions between alkylamines and ammonium salts (ammonium sulfate and ammonium bisulfate) have been studied using a low-pressure fast flow reactor coupled to an ion drift-chemical ionization mass spectrometer (ID-CIMS) at 293 ± 2 K. The uptake of three alkylamines, i.e., monomethylamine, dimethylamine, and trimethylamine, on ammonium sulfate shows a displacement reaction of ammonium by aminium, evidenced by the release of ammonia monitored using protonated acetone dimer as the reagent ion. For the three alkylamines, the initial uptake coefficients (γ(0)) range from 2.6 × 10(-2) to 3.4 × 10(-2) and the steady-state uptake coefficients (γ(ss)) range from 6.0 × 10(-3) to 2.3 × 10(-4) and decrease as the number of methyl groups on the alkylamine increases. A different reaction mechanism is observed for the uptake of the three alkylamines on ammonium bisulfate, which is featured by an acid-base reaction (neutralization) with irreversible alkylamine loss and no ammonia generation and occurs at a rate limited by diffusion of gaseous alkylamines to the ammonium bisulfate surface. Our results reveal that the reactions between alkylamines and ammonium salts contribute to particle growth and alter the composition of ammonium sulfate and bisulfate aerosols in the atmosphere.

  20. Ammonium on Ceres

    Science.gov (United States)

    Ammannito, E.; De Sanctis, M. C.; Carrorro, F. G.; Ciarniello, M.; Combe, J. P.; De Angelis, S.; Ehlmann, B. L.; Frigeri, A.; Longobardo, A.; Mugnuolo, R.; Marchi, S.; Palomba, E.; Raymond, C. A.; Salatti, M.; Tosi, F.; Zambon, F.; Russell, C. T.

    2017-12-01

    Since January 2015, the surface of Ceres has been studied by the Dawn spacecraft through the measurements from the three instruments on board (1). The VIR imaging spectrometer, sensitive to the spectral range 0.25 -5.0 μm, provided information on the surficial composition of Ceres at resolutions ranging from few kilometers to about one hundred meters (2). Analysis of VIR reflectance data revealed that the average spectrum of Ceres is compatible with a mixture of low-albedo minerals, Mg- phyllosilicates, ammoniated clays, and Mg- carbonates, (3) confirming previous studies based on ground based spectra (4, 5). Mineralogical maps of the surface at about 1 km/px show that the components identified in the average spectrum are present all across the surface with variations in their relative abundance and chemical composition (6, 7). While the ammoniated clays have been already studied (6), the presence nature and distribution of additional ammoniated species has never been investigated in detail, although the spectral analysis of the bright faculae within Occator crater already revealed the potential presence of ammonium salts (8). Since the position and shape of the ammonium absorption in the VIS-NIR region are function of the hosting mineral specie (8), we did an inventory and characterization of the ammonium-rich regions, in order to analyze their spectral properties. In addition to the presence of ammonium, also the identification of the hosting species has implication for the evolution of Ceres. Our study, therefore, is a step forward in understanding of evolutionary pathway of Ceres. References: (1) Russell, C. T. et al., Science, 2016. (2) De Sanctis M.C. et al., Space Science Reviews, 2011. (3) De Sanctis M.C. et al., Nature, 2015. (4) King T. et al. Science, 1992. (5) Rivkin A.S. et al. Icarus, 2006. (6) Ammannito E. et al., Science, 2016. (7) Carrozzo F.G. et al., Science Advances, in revision. (8) De Sanctis et al., Nature, 2016. (9) Berg et al., Icarus

  1. Crystallisation of mixtures of ammonium nitrate, ammonium sulphate and soot

    NARCIS (Netherlands)

    Dougle, P.G.; Veefkind, J.P.; Brink, H.M. ten

    1998-01-01

    Crystallisation of laboratory aerosols of ammonium nitrate and of internal mixtures of this salt with ammonium sulphate were investigated using humidity controlled nephelometry. The aerosol was produced via nebulizing of solutions and then dried to 25% RH, which is a realistic minimum value for

  2. Phase characterization of precipitated zirconia

    International Nuclear Information System (INIS)

    Gutzov, S.; Ponahlo, J.; Lengauer, C.L.; Beran, A.

    1994-01-01

    The phase compositions of undoped and europium-doped zirconia samples, obtained by precipitation and thermal treatment from 350 to 1,000 C, have been investigated by powder X-ray diffractometry, infrared spectroscopy, and cathodoluminescence spectroscopy. The low-temperature stabilization of tetragonal zirconia is mainly controlled by the presence of anion additives, such as ammonium chloride. The influences of the crystallite size is less important. Cathodoluminescence spectra show a structural similarity between tetragonal and amorphous zirconia

  3. Ammonium diphosphitoindate(III

    Directory of Open Access Journals (Sweden)

    Farida Hamchaoui

    2013-04-01

    Full Text Available The crystal structure of the title compound, NH4[In(HPO32], is built up from InIII cations (site symmetry 3m. adopting an octahedral environment and two different phosphite anions (each with site symmetry 3m. exhibiting a triangular–pyramidal geometry. Each InO6 octahedron shares its six apices with hydrogen phosphite groups. Reciprocally, each HPO3 group shares all its O atoms with three different metal cations, leading to [In(HPO32]− layers which propagate in the ab plane. The ammonium cation likewise has site symmetry 3m.. In the structure, the cations are located between the [In(HPO32]− layers of the host framework. The sheets are held together by hydrogen bonds formed between the NH4+ cations and the O atoms of the framework.

  4. Ammonium Perchlorate and Ammonium Perchlorate- Hydroxyl Terminated Polybutadiene Simulated Combustion

    Directory of Open Access Journals (Sweden)

    Rene Francisco Boschi Gonçalves

    2012-03-01

    Full Text Available The combustion simulation of ammonium perchlorate was carried out with the software Chemkin, in two steps: the burning behavior of pure ammonium perchlorate and the one of formulated ammonium perchlorate with hydroxyl terminated polybutadiene binder. In both cases, the room pressure varied in order to verify its influence in the system. The burning environment conditions were diverse. During the combustion process, the data obtained from the kinetic chemistry simulation software were compiled. The flame structure can be described by the molar fraction of the burning products and the temperature evolution from the surface of the material.

  5. Pilot scale for preparation of ammonium uranyl carbonate

    International Nuclear Information System (INIS)

    Santos, L.R. dos.

    1989-01-01

    The procedure adopted for obtaining Ammonium Uranyl Carbonate (AUC) from uranium hexafluoride (UF sub(6)) or aqueous solutions of uranylnitrate (UO sub(2)(NO sub(3)) sub(2)) is described in the present work. This procedure involves the precipitation of AUC in a chemical reactor by the addition of gaseous UF sub(6) or solutions of uranylnitrate to NH sub(3) and CO sub(2) gases in a solution containing ammonium bicarbonate, where pH and temperature are controlled. Details regarding the characterization and quality control methods in the preparation of AUC are presented along with their physical and chemical properties. Some informations about effluents generated during the process are presented too. An attempt is made to correlate the parameters involved in the precipitation process of AUC and their characteristics. (author)

  6. 21 CFR 184.1143 - Ammonium sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium sulfate. 184.1143 Section 184.1143 Food... Specific Substances Affirmed as GRAS § 184.1143 Ammonium sulfate. (a) Ammonium sulfate ((NH4)2SO4, CAS Reg... is prepared by the neutralization of sulfuric acid with ammonium hydroxide. (b) The ingredient meets...

  7. Relations of ammonium minerals at several hydrothermal systems in the western U.S.

    Science.gov (United States)

    Krohn, M.D.; Kendall, C.; Evans, J.R.; Fries, T.L.

    1993-01-01

    Ammonium bound to silicate and sulfate minerals has recently been located at several major hydrothermal systems in the western U.S. utilizing newly-discovered near-infrared spectral properties. Knowledge of the origin and mineralogic relations of ammonium minerals at known hydrothermal systems is critical for the proper interpretation of remote sensing data and for testing of possible links to mineralization. Submicroscopic analysis of ammonium minerals from two mercury- and gold-bearing hot-springs deposits at Ivanhoe, Nevada and McLaughlin, California shows that the ammonium feldspar, buddingtonite, occurs as fine-grained euhedral crystals coating larger sulfide and quartz crystals. Ammonium feldspar seems to precipitate relatively late in the crystallization sequence and shows evidence for replacement of NH4+ by K+ or other monovalent cations. Some buddingtonite is observed in close association with mercury, but not with gold. Ammonioalunite is found in a variety of isolated crystal forms at both deposits. Nitrogen isotopic values for ammonium-bearing minerals show a 14??? range in composition, precluding assignment of a specific provenance to the nitrogen. The correlations of nitrogen isotopic values with depth and ammonium content suggest some loss of nitrogen in the oxidizing supergene environment, possibly as a metastable mineral. The high ammonium content in these hydrothermal systems, the close association to mercury, and the small crystal size of the ammonium-bearing minerals all suggest that ammonium may be transported in a late-stage vapor phase or as an organic volatile. Such a process could lead to the formation of a non-carbonaceous organic aureole above a buried geothermal source. The discovery of a 10-km outcrop of ammonium minerals confirms that significant substitution of ammonium in minerals is possible over an extensive area and that remote sensing is a feasible means to detect such aureoles. ?? 1993.

  8. TCA precipitation.

    Science.gov (United States)

    Koontz, Laura

    2014-01-01

    Trichloroacetic acid (TCA) precipitation of proteins is commonly used to concentrate protein samples or remove contaminants, including salts and detergents, prior to downstream applications such as SDS-PAGE or 2D-gels. TCA precipitation denatures the protein, so it should not be used if the protein must remain in its folded state (e.g., if you want to measure a biochemical activity of the protein). © 2014 Elsevier Inc. All rights reserved.

  9. Influence of ammonium salts on the lipase/esterase activity assay using p-nitrophenyl esters as substrates.

    Science.gov (United States)

    De Yan, Hong; Zhang, Yin Jun; Liu, Hong Cai; Zheng, Jian Yong; Wang, Zhao

    2013-01-01

    p-Nitrophenyl esters with a short-chain carboxylic group, such as p-nitrophenyl acetate (p-NPA) and p-nitrophenyl butyrate (p-NPB), could be effectively hydrolyzed by ammonium salts. p-Nitrophenyl esters were usually used as substrates to assay the lipase/esterase activity. Ammonium sulfate precipitation was often used to purify proteins, and some ammonium salts were usually used as nitrogen sources or inorganic salts for the lipase/esterase production. To study the effect of ammonium salts on the assay of the lipase/esterase activity, the contributing factors of hydrolysis of p-NPA/p-NPB catalyzed by ammonium salts were investigated. The lipase activities were compared in the presence and absence of ammonium sulfate. The hydrolysis reaction could be catalyzed under neutral and alkaline circumstances. The hydrolysis rate increased with the increase in the reaction temperature or the concentration of ammonium ion. When p-NPA was employed as the substrate for the analysis of the lipase/esterase activity, the effect of ammonium sulfate on the analysis could be neutralized by setting a control when the concentration of ammonium sulfate was less than 40% saturation. However, when the concentration of ammonium sulfate increased from 40% to 100% saturation, the enzyme activities decreased about 13-40%, which could not be ignored for accurate analysis of the enzyme activity. © 2013 International Union of Biochemistry and Molecular Biology, Inc.

  10. Solubility of ammonium metavanadate in ammonium carbonate and sodium bicarbonate solutions at 25 deg C

    International Nuclear Information System (INIS)

    Fedorov, P.I.; Andreev, V.K.; Slotvinskij-Sidak, N.P.

    1978-01-01

    Solubility at 25 deg C has been studied in the system ammonium metavanadate - sodium bicarbonate - water which is a stable section of the corresponding quaternary mutual system. In the eutonic point the content of ammonium metavanadate is 4.95% and of sodium bicarbonate 12.1%. The crystallization branch of ammonium metavanadate has been studied in the system ammonium metavanadate - ammonium carbonate - water at 25 deg C. Metavanadate solubility attains minimum (0.14%) at ammonium carbonate concentration 2.6%. Three sections have been studied of the quaternary system ammonium - metavanadate - ammonium carbonate - sodium bicarbonate-water at 25 deg C in the crystallization region of ammonium metavanadate at a ratio of sodium bicarbonate to ammonium carbonate 3:1, 1:1, and 1:3. A region of minimum solubility of ammonium metavanadate has been detected (0.1%)

  11. Study of ammonium sulfates electric conductivity

    International Nuclear Information System (INIS)

    Dobrynin, D.V.; Tulegulov, A.D.

    2006-01-01

    In the work results of research of ammonium sulfate electroconductivity are given. The influence effecting on ammonium sulfate conductivity is investigated. The various circuits of inclusion tetra ohmmeter are given. (author)

  12. 21 CFR 184.1133 - Ammonium alginate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium alginate. 184.1133 Section 184.1133 Food... Specific Substances Affirmed as GRAS § 184.1133 Ammonium alginate. (a) Ammonium alginate (CAS Reg. No. 9005... accordance with § 184.1(b)(2), the ingredient is used in food only within the following specific limitations...

  13. 21 CFR 582.1141 - Ammonium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ammonium phosphate. 582.1141 Section 582.1141 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1141 Ammonium phosphate. (a) Product. Ammonium phosphate (mono- and dibasic). (b) Conditions...

  14. 76 FR 47238 - Ammonium Nitrate From Russia

    Science.gov (United States)

    2011-08-04

    ... COMMISSION Ammonium Nitrate From Russia Determination On the basis of the record \\1\\ developed in the subject... order on ammonium nitrate from Russia would be likely to lead to continuation or recurrence of material... Commission are contained in USITC Publication 4249 (August 2011), entitled Ammonium Nitrate from Russia...

  15. 21 CFR 582.1143 - Ammonium sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ammonium sulfate. 582.1143 Section 582.1143 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1143 Ammonium sulfate. (a) Product. Ammonium sulfate. (b) Conditions of use. This substance...

  16. Pilot plant development of processes for the production of ammonium diuranate

    International Nuclear Information System (INIS)

    Janov, J.; Alfredson, P.G.; Vilkaitis, V.K.

    1975-01-01

    Nuclear grade ammonium diuranate (ADU) and UO 2 powders were produced on a pilot plant scale by the continuous single-stage precipitation of ADU with ammonium hydroxide, dewatering with a rotary drum vacuum filter or a solid bowl centrifuge, and batch-tray drying and calcination-reduction to UO 2 powder. Precipitation at 50 0 C and pH values in the range 7.2 to 8.0 produced ADU materials which could be converted to UO 2 powder by calcination and reduction at temperatures of 600 to 730 0 C, and fabricated into sintered pellets with densities of 10.37 to 10.77 g cm -3 . The lower the pH of precipitation the lower was the reduction temperature required to achieve a specified pellet density. Precipitation with ammonium hydroxide at 80 0 C and with ammonia gas at 50 0 C offered no advantages over precipitation with ammonium hydroxide at 50 0 C. The UO 2 powders and sintered pellets produced from ADU powders precipitated by the three methods were similar. Precipitation at pH 7.5 and 50 0 C is recommended since a reasonably filterable precipitate can be produced reproducibly without a need for stringent control, and considerable flexibility is available in the subsequent production of a sinterable UO 2 powder. Dewatering of ADU slurries was carried out more efficiently using a solid bowl centrifuge rather than a rotary drum vacuum filter. Clearer discharge liquids were produced at a higher rate of throughput in the solid bowl centrifuge. (author)

  17. Precipitation of yellowcake from pregnant regenerate by various reagents

    International Nuclear Information System (INIS)

    Rychkov, V.N.; Smirnov, A.L.; Skripchenko, S.Yu.; Pastukhov, A.M.

    2017-01-01

    The application of an ammonia solution, sodium hydroxide solution and ammonium carbonate/bicarbonate solution as agents for the uranium precipitation from industrial pregnant regenerate was investigated. The effect various process parameters on the composition and properties of obtained uranium compounds was studied. According to the results, only the yellowcake obtained by precipitation using ammonium carbonate/bicarbonate solution is a high-purity product and meets the specification requirements. The uranium content in this concentrate is 69-72%. The particle mean diameter is 12-16 µm. The use of other neutralizing agents leads to decrease purity of the final product. (author)

  18. Co-precipitation synthesis and luminescence behavior of Ce-doped yttrium aluminum garnet (YAG:Ce) phosphor: The effect of precipitant

    International Nuclear Information System (INIS)

    Zhang Kai; Liu Hezhou; Wu Yating; Hu Wenbin

    2008-01-01

    YAG:Ce precursors were co-precipitated using ammonia water and ammonium hydrogen carbonate as precipitants, respectively. Phase transition of the precursors during sintering was compared between the two precipitants. The precursors synthesized with ammonia water transformed to YAG at about 1000 deg. C via YAlO 3 phase. The precursors synthesized with ammonium hydrogen carbonate directly converted to pure YAG at about 900 deg. C. Comparing the powders produced with the two precipitants, the powders produced with ammonia hydrogen carbonate showed good dispersity. When sintered at 1600 deg. C, aggregation of the powders synthesized with the two precipitants both became severe. With increase the sintering temperature, the maximum wavelength of excitation and emission spectra of the phosphors synthesized with ammonium water hardly varied. While the maximum wavelength of excitation spectra of the phosphors synthesized with ammonium hydrogen carbonate unchanged, and the emission spectra showed red shift. Because of size effect and higher loss of cerium content, the emission intensity of phosphors prepared with ammonium hydrogen carbonate was lower than the phosphors prepared with ammonium water, when sintered at the same temperature

  19. Treating ammonium-rich wastewater with sludge from water treatment plant to produce ammonium alum

    Directory of Open Access Journals (Sweden)

    Wen-Po Cheng

    2016-03-01

    Full Text Available This study applies a process to treat ammonium-rich wastewater using alum-generated sludge form water purification plant, and gain economic benefit by producing ammonium alum (Al(NH4(SO42·12H2O. The factors affecting production of ammonium alum include molar ratio of ammonium to aluminum concentration, sulfuric acid concentration, mixing speed, mixing time, standing time, and temperature. According to the equation for the ammonium removal reaction, the theoretical quantity of ammonium alum was calculated based on initial and final concentrations of ammonium. Then, the weight of ammonium alum crystal was divided by the theoretical weight to derive the recovery ratio. The optimum sludge and sulfuric acid dosage to treat about 17 g L−1 ammonium wastewater are 300 g L−1 and 100 mL L−1, respectively. The optimal dosage for wastewater is molar ratio of ammonium to aluminum of about 1 due to the aluminum dissolving in acidified wastewater. The ammonium removal efficiency is roughly 70% and the maximum recovery ratio for ammonium alum is 93% when the wastewater is mixed for 10 min at the mixing velocity gradient of 100 s−1. Ammonium alum production or ammonium removal can be enhanced by controlling the reaction at low temperatures.

  20. Precipitation of uranium concentrates by hydrogen peroxide

    International Nuclear Information System (INIS)

    Barbosa Filho, O.

    1986-12-01

    An experimental study on the (UO 4 .xH 2 ) uranyl peroxide precipitation from a uranium process strip solution is presented. The runs were performed in a batch reactor, in laboratory scale. The main objective was to assess the possibility of the peroxide route as an alternative to a conventional ammonium diuranate process. The chemical composition of process solution was obtained. The experiments were conducted according to a factorial design, aiming to evaluate the effects of initial pH, precipitation pH and H 2 O 2 /UO 2 2+ ratio upon the process. The responses were measured in terms of the efficiency of U precipitation, the content of U in the precipitates and the distribution of impurities in the precipitates. The results indicated that the process works is satisfactory on the studied conditions and depending on conditions, it is possible to achieve levels of U precipitation efficiency greater than 99.9% in reaction times of 2 hours. The precipitates reach grades around 99% U 3 O 8 after calcination (900 0 C) and impurities fall below the limit for penalties established by the ASTM and the Allied Chemical Standards. The precipitates are composed of large aggregates of crystals of 1-4 μm, are fast settling and filtering, and are free-flowing when dry. (Author) [pt

  1. Ammonium azide under hydrostatic compression

    Science.gov (United States)

    Landerville, A. C.; Steele, B. A.; Oleynik, I. I.

    2014-05-01

    The properties of ammonium azide NH4N3 upon compression were investigated using first-principles density functional theory. The equation of state was calculated and the mechanism of a phase transition experimentally observed at 3.3 GPa is elucidated. Novel polymorphs of NH4N3 were found using a simple structure search algorithm employing random atomic displacements upon static compression. The structures of three new polymorphs, labelled as B, C, and D, are similar to those of other metal azides.

  2. Characterization of alumina obtained from the synthesis of gelatinous precipitates of aluminum hydroxide obtained from the reaction of aluminum sulfate and ammonium hydroxide in different temperatures; Caracterizacao de aluminas obtidas a partir da sintese de precipitados gelatinosos de hidroxido de aluminio obtidos pela reacao de sulfato de aluminio e hidroxido de amonio em diferentes temperaturas

    Energy Technology Data Exchange (ETDEWEB)

    Mercury, Jose Manuel Rivas [Centro Federal de Educacao Tecnologica do Maranhao (CEFET), Sao Luiz, MA (Brazil); Freitas Neves, R. de [Para Univ., Belem, Pa (Brazil). Dept. de Engenharia Quimica

    1996-07-01

    Aluminum hydroxide was obtained by synthesis through neutralization of solutions aluminum sulphate solutions with ammonium hydroxide at different level of temperatures of synthesis (30, 60, 90 deg C) on the molar [OH]/[Al{sup +3}] of 6,5. All products was burned at 950 deg C during two hours of dried aluminum hydroxide powder. Alumina obtained and A-16SG, APC-2011, produced by Alcoa Co. was characterized by Bulk Density, Tap density, Real Density, Particle Size Distribution, X-Ray Diffractions and Chemical Analysis and both compared. (author) 11 refs., 3 figs., 3 tabs.

  3. 21 CFR 184.1138 - Ammonium chloride.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium chloride. 184.1138 Section 184.1138 Food... Specific Substances Affirmed as GRAS § 184.1138 Ammonium chloride. (a) Ammonium chloride (NH4Cl, CAS Reg..._locations.html. (c) In accordance with § 184.1(b)(1), the ingredient is used in food with no limitation...

  4. 21 CFR 184.1137 - Ammonium carbonate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium carbonate. 184.1137 Section 184.1137 Food... Specific Substances Affirmed as GRAS § 184.1137 Ammonium carbonate. (a) Ammonium carbonate ((NH4)2CO3, CAS.../code_of_federal_regulations/ibr_locations.html. (c) In accordance with § 184.1(b)(1), the ingredient is...

  5. Glufosinate ammonium selection of transformed Arabidopsis.

    Science.gov (United States)

    Weigel, Detlef; Glazebrook, Jane

    2006-12-01

    INTRODUCTIONOne of the most commonly used markers for the selection of transgenic Arabidopsis is resistance to glufosinate ammonium, an herbicide that is sold under a variety of trade names including Basta and Finale. Resistance to glufosinate ammonium is conferred by the bacterial bialophos resistance gene (BAR) encoding the enzyme phosphinotricin acetyl transferase (PAT). This protocol describes the use of glufosinate ammonium to select transformed Arabidopsis plants. The major advantage of glufosinate ammonium selection is that it can be performed on plants growing in soil and does not require the use of sterile techniques.

  6. Synthesis of cerous ammonium nitrate using ceric ammonium nitrate and anhydrous ammonia as a reducing agent

    International Nuclear Information System (INIS)

    Bourleaux, G.; Colombet, P.; Rouxel, J.; Gradeff, P.S.; Mauermann, H.

    1988-01-01

    The reduction of ceric ammonium nitrate by anhydrous ammonia has been studied. The reaction yields cerous ammonium nitrate complex. This is an easy method to prepare an anhydrous Ce (III) salt, suitable for synthesis of organo cerium (III) derivatives [fr

  7. A mathematical relationship for hydromorphone loading into liposomes with trans-membrane ammonium sulfate gradients.

    Science.gov (United States)

    Tu, Sheng; McGinnis, Tamara; Krugner-Higby, Lisa; Heath, Timothy D

    2010-06-01

    We have studied the loading of the opioid hydromorphone into liposomes using ammonium sulfate gradients. Unlike other drugs loaded with this technique, hydromorphone is freely soluble as the sulfate salt, and, consequently, does not precipitate in the liposomes after loading. We have derived a mathematical relationship that can predict the extent of loading based on the ammonium ion content of the liposomes and the amount of drug added for loading. We have adapted and used the Berthelot indophenol assay to measure the amount of ammonium ions in the liposomes. Plots of the inverse of the fraction of hydromorphone loaded versus the amount of hydromorphone added are linear, and the slope should be the inverse of the amount of ammonium ions present in the liposomes. The inverse of the slopes obtained closely correspond to the amount of ammonium ions in the liposomes measured with the Berthelot indophenol assay. We also show that loading can be less than optimal under conditions where osmotically driven loss of ammonium ions or leakage of drug after loading may occur. (c) 2009 Wiley-Liss, Inc. and the American Pharmacists Association

  8. Atmospheric behaviour of ammonia and ammonium

    NARCIS (Netherlands)

    Asman, W.A.H.

    1987-01-01

    1.4.1 Scope of this thesis

    A few models for ammonia and ammonium exist. Russell et al. (1983) made a multi-layer Lagrangian transport model describing the transport and formation of ammonium nitrate aerosol for California. They did not take reactions of ammonia and sulphuric acid

  9. 21 CFR 582.1135 - Ammonium bicarbonate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ammonium bicarbonate. 582.1135 Section 582.1135 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE General Purpose Food Additives § 582.1135 Ammonium bicarbonate. (a)...

  10. Optimization of nutritional requirements and ammonium feeding ...

    African Journals Online (AJOL)

    tounukarin

    2011-09-07

    Sep 7, 2011 ... defined medium and to develop an ammonium control strategy to optimize the specific vitamin B12 production rate (Yp) ... Key words: Statistical designs, Pseudomonas denitrificans, chemically defined medium, ammonium controlling strategy ... analysis provides a powerful tool for effective quanti- fication of ...

  11. 76 FR 46907 - Ammonium Nitrate Security Program

    Science.gov (United States)

    2011-08-03

    ... located in, under, or adjacent to any waters subject to the jurisdiction of the United States. Through its..., marking, labeling, placarding, security plans, emergency response information, training, etc.). f... ``solid ammonium nitrate that is chiefly the ammonium salt of nitric acid and contains not less than 33...

  12. Effects of ammonium concentration and charge exchange on ammonium recovery from high strength wastewater using a microbial fuel cell

    NARCIS (Netherlands)

    Kuntke, P.; Geleij, M.; Bruning, H.; Zeeman, G.; Hamelers, H.V.M.; Buisman, C.J.N.

    2011-01-01

    Ammonium recovery using a 2 chamber microbial fuel cell (MFC) was investigated at high ammonium concentration. Increasing the ammonium concentration (from 0.07 g to 4 g ammonium-nitrogen/L) by addition of ammonium chloride did not affect the performance of the MFC. The obtained current densities by

  13. Lichens as biomonitors of atmospheric ammonium/ammonia deposition in Portugal

    International Nuclear Information System (INIS)

    Capelao, A.L.; Maguas, C.; Branquinho, C.; Cruz, C.; Martins-Loucao, M.A.

    2000-01-01

    The aim of the present work was to evaluate the potentiality of lichens as biomonitors of NH 4 + /NH 3 (ammonium/ammonia) and NO 3 - (nitrate) atmospheric deposition. For that, we used as a field station a rice plantation which is submitted, once a year, to air spraying fertilization with a mixture of nitrogen sources. Samples of an epiphytic lichen, Ramalina fastigiata, were collected from an ash-tree bordering the rice-plantation by the Sorraia River Valley (Central Portugal). The study started one month before fertilization and sampling was carried out for five months. The concentration of ammonium in the lichen was highly and significantly correlated with the number of days without precipitation before sampling, and had an inverse correlation with fluorescence values. Under these conditions, the amount of NH 4 + found in the lichen appears to reflect ammonium/ammonia dry deposition. (author)

  14. Metal-free catalytic oxidation of sulfides to sulfoxides with ammonium nitrate, ammonium hydrogen sulfate and ammonium bromide as catalyst

    OpenAIRE

    Ghorbani-Choghamarani, Arash; Zolfigol, Mohammad Ali; Ayazi-Nasrabadi, Roia

    2010-01-01

    A general and metal-free catalytic oxidation of aliphatic and aromatic sulfides to their corresponding sulfoxides via combination of ammonium nitrate (NH4NO3), supported ammonium hydrogen sulfate on silica gel (NH4HSO4-SiO2) and a catalytic amount of ammonium bromide (NH4Br) in the presence of wet SiO2 (50%, w/w) has been investigated. The reactions were carried out heterogeneously and selectively in short reaction times in CH2Cl2 at room temperature. This protocol is mild and efficient compa...

  15. Ammonium sulfate preparation from phosphogypsum waste

    Directory of Open Access Journals (Sweden)

    Abdel-Hakim T. Kandil

    2017-01-01

    Full Text Available The Egyptian phosphogypsum waste is treated using sulfuric acid prior the ammonium sulfate production. The relevant factors that would affect the removal efficiencies of some impurities are studied. The optimum conditions of the treatment are 8 M sulfuric acid solution and 1/4 solid/liquid ratio for 30 min contact time at 80 °C. Moreover, the optimum conditions of the ammonium sulfate preparation are 10 g of the suspended impure or purified phosphogypsum in 40 ml of 3% ammonium sulfate solution (as initiator, 1/4 solid/liquid ratio at pH7 at an addition of an excess ammonium carbonate, and 150 rpm stirring speed for 4.0 h contact time at 55 °C as well as the 5 mg of barium chloride is added to remove the radium in the ammonium sulfate product. Finally, the ammonium sulfate is crystallized and the chemical analysis of the product shows 20% nitrogen and 23.6% sulfur. Therefore, the purity of the obtained ammonium sulfate is 95% from the purified phosphogypsum.

  16. Flotation separation of strontium via phosphate precipitation.

    Science.gov (United States)

    Thanh, Luong H V; Liu, J C

    2017-06-01

    Flotation separation of strontium (Sr) from wastewater via phosphate precipitation was investigated. While 37.33% of Sr precipitated at highly alkaline pH in the absence of PO 4 3- , it completely precipitated as Sr 3 (PO 4 ) 2 at a molar ratio ([PO 4 3- ]:[Sr 2+ ]) of 0.62 at a lower pH value. The presence of Ca 2+ hindered Sr precipitation, yet it could be overcome by increasing the PO 4 3- dose. Sodium dodecyl sulfate (SDS) was a better collector for dispersed air flotation of Sr 3 (PO 4 ) 2 than cetyl trimethyl ammonium bromide, or mixed collector systems of SDS and saponin. The highest separation efficiency of 97.5% was achieved at an SDS dose of 40 mg/L. The main mechanism in the precipitate flotation is adsorption of anionic SDS on the positively charged surface of colloidal Sr 3 (PO 4 ) 2 via electrostatic interaction. SDS enhanced the aggregation of Sr 3 (PO 4 ) 2 precipitates as the size increased from 1.65 to 28.0 μm, which was beneficial to separation as well.

  17. A NEW PROCESS DEVELOPED FOR SEPARATION OF LIGNIN FROM AMMONIUM HYDROXIDE PRETREATMENT SOLUTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Sherman, S.; Gorensek, M.; Milliken, C.

    2010-12-14

    A method is described for separating lignin from liquid solutions resulting from the pretreatment of lignocellulosic materials such as switchgrass with ammonium hydroxide. The method involves a sequence of steps including acidification, evaporation, and precipitation or centrifugation that are performed under defined conditions, and results in a relatively pure, solid lignin product. The method is tested on ammonium hydroxide solutions containing lignin extracted from switchgrass. Experimental results show that the method is capable of recovering between 66-95% of dissolved lignin as a precipitated solid. Cost estimates of pilot-scale and industrial-scale expressions of the process indicate that breakeven lignin prices of $2.36/kg and $0.78/kg, respectively, may be obtainable with this recovery method.

  18. Ammonium sulfate preparation from phosphogypsum waste

    OpenAIRE

    Kandil, Abdel-Hakim T.; Cheira, Mohamed F.; Gado, Hady S.; Soliman, Madiha H.; Akl, Hesham M.

    2017-01-01

    The Egyptian phosphogypsum waste is treated using sulfuric acid prior the ammonium sulfate production. The relevant factors that would affect the removal efficiencies of some impurities are studied. The optimum conditions of the treatment are 8 M sulfuric acid solution and 1/4 solid/liquid ratio for 30 min contact time at 80 °C. Moreover, the optimum conditions of the ammonium sulfate preparation are 10 g of the suspended impure or purified phosphogypsum in 40 ml of 3% ammonium sulfate soluti...

  19. Stripping study of U(VI) from loaded TBP/n-paraffin using ammonium nitrate bearing waste as strippant

    International Nuclear Information System (INIS)

    Shrishma Paik; Biswas, S.; Bhattacharya, S.; Roy, S.B.

    2013-01-01

    Stripping studies of U(VI) from loaded solvent TBP/n-paraffin was carried out using ammonium nitrate solution as strippant. Effects of various stripping parameters such as concentration of ammonium nitrate solution, U(VI) concentration in organic phase, initial pH of strippant, temperature etc. have been investigated in detail. Kinetics of the stripping process by ammonium nitrate was found to be slower than that of stripping with water. It was observed that with the increase in ammonium nitrate concentration in aqueous solution, stripping of U(VI) decreased. With the increase in U(VI) loading in the organic phase, there was an increase in uranium stripping for ammonium nitrate whereas for distilled water it becomes reverse. With the increase in pH of the aqueous ammonium nitrate solution, stripping increased up to a certain pH of 8.5 and after that precipitation of uranium started. Increase in temperature of the biphasic system shows an enhancing effect of U(VI) stripping. Evaluation of thermodynamic data such as ΔH indicated that the process is endothermic. Based on the optimized conditions, McCabe-Thiele diagram was constructed for U(VI) stripping using ammonium nitrate solution at room temperature. (author)

  20. Ammonium uranate in spherical particles running easily and its fabrication process

    International Nuclear Information System (INIS)

    Dugua, Jacques.

    1980-01-01

    Preparation of ammonium diuranate easy to handle with spherical grains of mean diameter between 40 to 100 microns, of unpressed apparent specific weight between 2 to 2.8 g/cm 3 and with a SO 4 ion content between 0.5 to 1 %. It is obtained by reaction of uranyl sulfate on ammonia and precipitation at a pH value between 6.6 to 7.2 [fr

  1. Arctic water tracks retain phosphorus and transport ammonium

    Science.gov (United States)

    Harms, T.; Cook, C. L.; Wlostowski, A. N.; Godsey, S.; Gooseff, M. N.

    2017-12-01

    Hydrologic flowpaths propagate biogeochemical signals among adjacent ecosystems, but reactions may attenuate signals by retaining, removing, or transforming dissolved and suspended materials. The theory of nutrient spiraling describes these simultaneous reaction and transport processes, but its application has been limited to stream channels. We applied nutrient spiraling theory to water tracks, zero-order channels draining Arctic hillslopes that contain perennially saturated soils and flow at the surface either perennially or in response to precipitation. In the Arctic, experimental warming results in increased availability of nitrogen, the limiting nutrient for hillslope vegetation at the study site, which may be delivered to aquatic ecosystems by water tracks. Increased intensity of rain events, deeper snowpack, earlier snowmelt, and increasing thaw depth resulting from climate change might support increased transport of nutrients, but the reactive capacity of hillslope flowpaths, including sorption and uptake by plants and microbes, could counter transport to regulate solute flux. Characteristics of flowpaths might influence the opportunity for reaction, where slower flowpaths increase the contact time between solutes and soils or roots. We measured nitrogen and phosphorus uptake and transient storage of water tracks through the growing season and found that water tracks retain inorganic phosphorus, but transport ammonium. Nutrient uptake was unrelated to transient storage, suggesting high capacity for nutrient retention by shallow organic soils and vegetation. These observations indicate that increased availability of ammonium, the biogeochemical signal of warming tundra, is propagated by hillslope flowpaths, whereas water tracks attenuate delivery of phosphorus to aquatic ecosystems, where its availability typically limits production.

  2. Effects of ammonium on uranium partitioning and kaolinite mineral dissolution.

    Science.gov (United States)

    Emerson, Hilary P; Di Pietro, Silvina; Katsenovich, Yelena; Szecsody, Jim

    2017-02-01

    Ammonia gas injection is a promising technique for the remediation of uranium within the vadose zone. It can be used to manipulate the pH of a system and cause co-precipitation processes that are expected to remove uranium from the aqueous phase and decrease leaching from the solid phase. The work presented in this paper explores the effects of ammonium and sodium hydroxide on the partitioning of uranium and dissolution of the kaolinite mineral in simplified synthetic groundwaters using equilibrium batch sorption and sequential extraction experiments. It shows that there is a significant increase in uranium removal in systems with divalent cations present in the aqueous phase but not in sodium chloride synthetic groundwaters. Further, the initial conditions of the aqueous phase do not affect the dissolution of kaolinite. However, the type of base treatment does have an effect on mineral dissolution. Published by Elsevier Ltd.

  3. Electrochemically and Bioelectrochemically Induced Ammonium Recovery

    Science.gov (United States)

    Gildemyn, Sylvia; Luther, Amanda K.; Andersen, Stephen J.; Desloover, Joachim; Rabaey, Korneel

    2015-01-01

    Streams such as urine and manure can contain high levels of ammonium, which could be recovered for reuse in agriculture or chemistry. The extraction of ammonium from an ammonium-rich stream is demonstrated using an electrochemical and a bioelectrochemical system. Both systems are controlled by a potentiostat to either fix the current (for the electrochemical cell) or fix the potential of the working electrode (for the bioelectrochemical cell). In the bioelectrochemical cell, electroactive bacteria catalyze the anodic reaction, whereas in the electrochemical cell the potentiostat applies a higher voltage to produce a current. The current and consequent restoration of the charge balance across the cell allow the transport of cations, such as ammonium, across a cation exchange membrane from the anolyte to the catholyte. The high pH of the catholyte leads to formation of ammonia, which can be stripped from the medium and captured in an acid solution, thus enabling the recovery of a valuable nutrient. The flux of ammonium across the membrane is characterized at different anolyte ammonium concentrations and currents for both the abiotic and biotic reactor systems. Both systems are compared based on current and removal efficiencies for ammonium, as well as the energy input required to drive ammonium transfer across the cation exchange membrane. Finally, a comparative analysis considering key aspects such as reliability, electrode cost, and rate is made. This video article and protocol provide the necessary information to conduct electrochemical and bioelectrochemical ammonia recovery experiments. The reactor setup for the two cases is explained, as well as the reactor operation. We elaborate on data analysis for both reactor types and on the advantages and disadvantages of bioelectrochemical and electrochemical systems. PMID:25651406

  4. 33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

    Science.gov (United States)

    2010-07-01

    ..., combustible liquids, corrosive liquids, chlorates, permanganates, finely divided metals, caustic soda... molten ammonium nitrate if a fire occurred (and thus become potential detonators for the storage piles...

  5. Capacity and mechanisms of ammonium and cadmium sorption on different wetland-plant derived biochars

    International Nuclear Information System (INIS)

    Cui, Xiaoqiang; Hao, Hulin; Zhang, Changkuan; He, Zhenli; Yang, Xiaoe

    2016-01-01

    The objective of this study was to investigate the relationship between Cd 2+ /NH 4 + sorption and physicochemical properties of biochars produced from different wetland plants. Biochars from six species of wetland plants (i.e., Canna indica, Pennisetum purpureum Schum, Thalia dealbata, Zizania caduciflora, Phragmites australis and Vetiveria zizanioides) were obtained at 500 °C and characterized, and their sorption for ammonium and cadmium was determined. There were significant differences in elemental composition, functional groups and specific surface area among the biochars derived from different wetland plant species. Sorption of ammonium and cadmium on the biochars could be described by a pseudo second order kinetic model, and the simple Langmuir model fits the isotherm data better than the Freundlich or Temkin model. The C. indica derived biochar had the largest sorption capacity for NH 4 + and Cd 2+ , with a maximum sorption of 13.35 and 125.8 mg g −1 , respectively. P. purpureum Schum derived biochar had a similar maximum sorption (119.3 mg g −1 ) for Cd 2+ . Ammonium sorption was mainly controlled by cation exchange, surface complexation with oxygen-containing functional groups and the formation of magnesium ammonium phosphate compounds, whereas for Cd 2+ sorption, the formation of cadmium phosphate precipitates, cation exchange and binding to oxygen-containing groups were the major possible mechanisms. In addition, the sorption of ammonium and cadmium was not affected by surface area and microporosity of the biochars. - Highlights: • Biochars varied in physicochemical properties and adsorption capacity. • Canna indica derived biochar has a high sorption capacity for Cd 2+ . • NH 4 + and Cd 2+ sorption on biochars fits a pseudo second order and Langmuir model. • Sorption mechanism is related to complexation, cation exchange and precipitation.

  6. Capacity and mechanisms of ammonium and cadmium sorption on different wetland-plant derived biochars

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Xiaoqiang [Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Hao, Hulin [Ningbo Raw Water Resource Research Academy, Ningbo (China); Zhang, Changkuan [Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); He, Zhenli [Indian River Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, Fort Pierce, FL 34945 (United States); Yang, Xiaoe, E-mail: xyang571@yahoo.com [Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China)

    2016-01-01

    The objective of this study was to investigate the relationship between Cd{sup 2+}/NH{sub 4}{sup +} sorption and physicochemical properties of biochars produced from different wetland plants. Biochars from six species of wetland plants (i.e., Canna indica, Pennisetum purpureum Schum, Thalia dealbata, Zizania caduciflora, Phragmites australis and Vetiveria zizanioides) were obtained at 500 °C and characterized, and their sorption for ammonium and cadmium was determined. There were significant differences in elemental composition, functional groups and specific surface area among the biochars derived from different wetland plant species. Sorption of ammonium and cadmium on the biochars could be described by a pseudo second order kinetic model, and the simple Langmuir model fits the isotherm data better than the Freundlich or Temkin model. The C. indica derived biochar had the largest sorption capacity for NH{sub 4}{sup +} and Cd{sup 2+}, with a maximum sorption of 13.35 and 125.8 mg g{sup −1}, respectively. P. purpureum Schum derived biochar had a similar maximum sorption (119.3 mg g{sup −1}) for Cd{sup 2+}. Ammonium sorption was mainly controlled by cation exchange, surface complexation with oxygen-containing functional groups and the formation of magnesium ammonium phosphate compounds, whereas for Cd{sup 2+} sorption, the formation of cadmium phosphate precipitates, cation exchange and binding to oxygen-containing groups were the major possible mechanisms. In addition, the sorption of ammonium and cadmium was not affected by surface area and microporosity of the biochars. - Highlights: • Biochars varied in physicochemical properties and adsorption capacity. • Canna indica derived biochar has a high sorption capacity for Cd{sup 2+}. • NH{sub 4}{sup +} and Cd{sup 2+} sorption on biochars fits a pseudo second order and Langmuir model. • Sorption mechanism is related to complexation, cation exchange and precipitation.

  7. 49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

    Science.gov (United States)

    2010-10-01

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

  8. Application of anaerobic ammonium-oxidizing consortium to achieve completely autotrophic ammonium and sulfate removal.

    Science.gov (United States)

    Liu, Sitong; Yang, Fenglin; Gong, Zheng; Meng, Fangang; Chen, Huihui; Xue, Yuan; Furukawa, Kenji

    2008-10-01

    The simultaneous ammonium and sulfate removal was detected in an anammox reactor, consisted of ammonium oxidization with sulfate deoxidization, and subsequently traditional anammox process, in via of middle medium nitrite with solid sulfur and N2 as the terminal products. The pure anammox bacteria offered a great biotechnological potential for the completely autotrophic reaction indicated by batch tests. Denaturing gradient gel electrophoresis (DGGE) analysis further revealed that a new organism belonging to Planctomycetales was strongly enriched in the defined niche: the redox of ammonium and sulfate. The new species "Anammoxoglobussulfate" was so considered as holding a critical role in the ammonium oxidization with sulfate deoxidization to nitrite. Afterwards, the Planctomyces existing in the bacteria community performed the anammox process together to achieve the complete nitrogen and sulfate removal. The potential use of sulfate as electron acceptor for ammonium oxidizing widens the usage of anammox bacteria.

  9. Reduction in Ammonium Ions in Sludge Liquor

    Directory of Open Access Journals (Sweden)

    Eglė Šlajūtė

    2013-12-01

    Full Text Available Liquor rejected from the centrifugation of the digested sludge can contain the concentrations of ammonium ions up to 1750 mg/L. These loads are usually returned to the intake of wastewater treatment plants (WWTP without additional treatment and can have a negative impact on biological wastewater and/or sludge treatment processes, e.g. phosphorus and nitrogen removal. This article deals with the use of naturally obtained sorbent, zeolite, in batch and column test procedure for removing ammonium from the rejected liquor. This research study was carried out using different sizes of zeolite particles: 0.8–1.6 mm and 1.6–2.5 mm. The highest efficiency of ammonium removal (up to 98 % was achieved by applying the zeolite particles of 0.8–1.6 mm.Article in Lithuanian

  10. The ammonium sulfate inhibition of human angiogenin.

    Science.gov (United States)

    Chatzileontiadou, Demetra S M; Tsirkone, Vicky G; Dossi, Kyriaki; Kassouni, Aikaterini G; Liggri, Panagiota G V; Kantsadi, Anastassia L; Stravodimos, George A; Balatsos, Nikolaos A A; Skamnaki, Vassiliki T; Leonidas, Demetres D

    2016-09-01

    In this study, we investigate the inhibition of human angiogenin by ammonium sulfate. The inhibitory potency of ammonium sulfate for human angiogenin (IC50 = 123.5 ± 14.9 mm) is comparable to that previously reported for RNase A (119.0 ± 6.5 mm) and RNase 2 (95.7 ± 9.3 mm). However, analysis of two X-ray crystal structures of human angiogenin in complex with sulfate anions (in acidic and basic pH environments, respectively) indicates an entirely distinct mechanism of inhibition. While ammonium sulfate inhibits the ribonucleolytic activity of RNase A and RNase 2 by binding to the active site of these enzymes, sulfate anions bind only to peripheral substrate anion-binding subsites of human angiogenin, and not to the active site. © 2016 Federation of European Biochemical Societies.

  11. Modelled Precipitation Over Greenland

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes the annual total precipitation from 1985 to 1999 and monthly total precipitation from January 1985 to December 1999. The data is derived from...

  12. On the evaporation of ammonium sulfate solution

    Energy Technology Data Exchange (ETDEWEB)

    Drisdell, Walter S.; Saykally, Richard J.; Cohen, Ronald C.

    2009-07-16

    Aqueous evaporation and condensation kinetics are poorly understood, and uncertainties in their rates affect predictions of cloud behavior and therefore climate. We measured the cooling rate of 3 M ammonium sulfate droplets undergoing free evaporation via Raman thermometry. Analysis of the measurements yields a value of 0.58 {+-} 0.05 for the evaporation coefficient, identical to that previously determined for pure water. These results imply that subsaturated aqueous ammonium sulfate, which is the most abundant inorganic component of atmospheric aerosol, does not affect the vapor-liquid exchange mechanism for cloud droplets, despite reducing the saturation vapor pressure of water significantly.

  13. On the evaporation of ammonium sulfate solution

    International Nuclear Information System (INIS)

    Drisdell, Walter S.; Saykally, Richard J.; Cohen, Ronald C.

    2009-01-01

    Aqueous evaporation and condensation kinetics are poorly understood, and uncertainties in their rates affect predictions of cloud behavior and therefore climate. We measured the cooling rate of 3 M ammonium sulfate droplets undergoing free evaporation via Raman thermometry. Analysis of the measurements yields a value of 0.58 ± 0.05 for the evaporation coefficient, identical to that previously determined for pure water. These results imply that subsaturated aqueous ammonium sulfate, which is the most abundant inorganic component of atmospheric aerosol, does not affect the vapor-liquid exchange mechanism for cloud droplets, despite reducing the saturation vapor pressure of water significantly.

  14. Global Distribution of Solid Ammonium Sulfate Aerosols and their Climate Impact Acting as Ice Nuclei

    Science.gov (United States)

    Zhou, C.; Penner, J.

    2017-12-01

    Laboratory experiments show that liquid ammonium sulfate particles effloresce when RHw is below 34% to become solid and dissolve when RHw is above 79%. Solid ammonium sulfate aerosols can act as heterogeneous ice nuclei particles (INPs) to form ice particles in deposition mode when the relative humidity over ice is above 120%. In this study we used the coupled IMPACT/CAM5 model to track the efflorescence and deliquescence processes of ammonium sulfate. Results show that about 20% of the total simulated pure sulfate aerosol mass is in the solid state and is mainly distributed in the northern hemisphere (NH) from 50 hPa to 200 hPa. When these solid ammonium sulfate aerosols are allowed to act as ice nuclei particles, they act to increase the ice water path in the NH and reduce ice water path in the tropics. The addition of these particles leads to a positive net radiative effect at the TOA ranging from 0.5-0.9 W/m2 depending on the amounts of other ice nuclei particles (e.g., dust, soot) used in the ice nucleation process. The short-term climate feedback shows that the ITCZ shifts northwards and precipitation increases in the NH. There is also an average warming of 0.05-0.1 K near the surface (at 2 meter) in the NH which is most obvious in the Arctic region.

  15. Leaching of lead by ammonium salts and EDTA from Salvinia minima biomass produced during aquatic phytoremediation

    Energy Technology Data Exchange (ETDEWEB)

    Nunez-Lopez, Roberto Aurelio [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica (CIDETEQ), Parque Tecnologico Queretaro, Sanfandila, Pedro Escobedo Qro., 76700 Mexico (Mexico)], E-mail: ndahi2000@yahoo.com; Meas, Yunny [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica (CIDETEQ), Parque Tecnologico Queretaro, Sanfandila, Pedro Escobedo Qro., 76700 Mexico (Mexico)], E-mail: yunnymeas@cideteq.mx; Citlalli Gama, Silvia; Ortega Borges, Raul [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica (CIDETEQ), Parque Tecnologico Queretaro, Sanfandila, Pedro Escobedo Qro., 76700 Mexico (Mexico); Olguin, Eugenia J. [Instituto de Ecologia (INECOL), Apdo. Postal 63, Xalapa, Veracruz 91000 (Mexico)

    2008-06-15

    Plant biomass harvested after heavy-metal phytoremediation must be considered as a hazardous waste that should be contained or treated appropriately before disposal or reuse. As a potential method to detoxify the biomass and to convert this material to a suitable fertilizer or mulch, leaching of lead (Pb) from Salvinia minima biomass was studied by testing water, several aqueous ammonium salts, and EDTA solution as lead extractants. The research was carried out in two phases: (i) a leaching study to determine the lead-extraction efficiency of the different leachants, and (ii) a thermodynamic analysis to identify the likely reactions and stable Pb(II) species formed in the leaching systems of the most efficient leachants. Experimentally, lead concentrations measured in leached biomass and in leachates were significantly different among the various leachants. It was determined that the extraction strength of the leachants followed the order: EDTA > ammonium oxalate > water {approx} ammonium nitrate > ammonium acetate, achieving Pb extraction efficiencies of 99%, 70%, 7.2%, 6.9% and 1.3%, respectively, in single-stage extractions. The thermodynamic study indicated that the dominant species produced by the leaching process should be the soluble species PbEDTA{sup 2-} for EDTA system, and the insoluble Pb(COO){sub 2S} precipitate for the oxalate system.

  16. Effects of Aromatic Ammoniums on Methyl Ammonium Lead Iodide Hybrid Perovskite Materials

    Directory of Open Access Journals (Sweden)

    Jianli Yang

    2017-01-01

    Full Text Available The introduction of bulky ammoniums into methyl ammonium lead iodide hybrid perovskites (MAPbI3 has emerged as a promising strategy to improve the properties of these materials. In the present work, we studied the effects of several aromatic ammoniums onto the structural, electronic, and optical properties of MAPbI3. Although powder XRD data suggest that the bulky cations are not involved in the bulk phase of the MAPbI3, a surprisingly large effect of the bulky cations onto the photoluminescence properties was observed.

  17. Tracing of salicylic acid additive during precipitation of zirconium

    International Nuclear Information System (INIS)

    Bharati Misra, U.; Gopala Krishna, K.; Narasimha Murty, B.; Yadav, R.B.

    2011-01-01

    This paper presents the results of experimental study carried out to know whether the salicylic acid used as an additive during the precipitation of zirconium using ammonium hydroxide solution goes into the filtrate, remains in the hydrated zirconia or gets distributed between the both under the ambient conditions of precipitation. Keeping its simplicity and amenability to adopt on a routine basis, spectrophotometric method has been chosen for the purpose among the many methods available and the problems associated in determining salicylic acid in the presence of zirconium and the medial measures to circumvent the same have been brought out in detail. (author)

  18. Spatial and temporal trends of precipitation chemistry in the United States, 1985-2002

    International Nuclear Information System (INIS)

    Lehmann, Christopher M.B.; Bowersox, Van C.; Larson, Susan M.

    2005-01-01

    A Seasonal Kendall Trend (SKT) test was applied to precipitation-weighted concentration data from 164 National Atmospheric Deposition Program National Trends Network (NADP/NTN) sites operational from 1985 to 2002. Analyses were performed on concentrations of ammonium, sulfate, nitrate, dissolved inorganic nitrogen (DIN, sum of nitrogen from nitrate and ammonium), and earth crustal cations (ECC, sum of calcium, magnesium, and potassium). Over the 18-year period, statistically significant (p ≤ 0.10) increases in ammonium concentrations occurred at 93 sites (58%), while just three sites had statistically significant ammonium decreases. Central and northern Midwestern states had the largest ammonium increases. The generally higher ammonium concentrations were accompanied by significant sulfate decreases (139 sites, 85%), and only one significant increase which occurred in Texas. In the west central United States there were significant nitrate increases (45 sites, 27%), while in the northeastern United States there were significant decreases (25 sites, 15%). Significant DIN decreases were observed in the northeastern United States (11 sites, 7%); elsewhere there were significant increases at 75 sites (46%). ECC decreased significantly at 65 sites (40%), predominately in the central and southern United States, and increased at 11 sites (7%). The concentrations of sulfate, nitrate, and ammonium in precipitation have changed markedly over the time period studied. Such trends indicate changes in the mix of gases and particles scavenged by precipitation, possibly reflecting changes in emissions, atmospheric chemical transformations, and weather patterns. - Data from the National Atmospheric Deposition Program National Trends Network indicate that significant changes in precipitation chemistry have occurred from 1985 to 2002

  19. Composition, Structural Evolution and the Related Property Variations in Preparation of Mixed Cesium/Ammonium Acidic Salts of Heteropolyacids

    Directory of Open Access Journals (Sweden)

    Heng Zhang

    2016-11-01

    Full Text Available The composition, structural evolution and the related property variations of mixed cesium/ammonium acidic salts of heteropolyacids were investigated in detail by tracking and analyzing the initial precipitates, evaporation residues and the calcined products in their preparation process. Results show that V cannot completely enter the heteropolyanions in the initial precipitates when the Cs+ added amount is low, and the increase in Cs+ adding amount improves the substitution of V for Mo in the heteropolyanions. Both the initial precipitates and the evaporation residues are mixtures of cesium and ammonium salts of heteropolyacids before calcination. Thermal treatment causes the decomposition of the ammonium salts and the formation of single-phase solid solutions from mechanical mixtures. The calcined products of the initial precipitates and the evaporation residues vary greatly in textural properties. The determinants of the catalytic performance for the oxidation of methacrolein to methacrylic acid are acidity and specific surface area of the compounds. The increase in specific surface area mainly improves the conversion of methacrolein, but not the selectivity of methacrylic acid. Insufficient acidity caused by high Cs+ content in the compounds is responsible for the low selectivity.

  20. Trends in atmospheric ammonium concentrations in relation to atmospheric sulfate and local agriculture.

    Science.gov (United States)

    Kelly, Victoria R; Lovett, Gary M; Weathers, Kathleen C; Likens, Gene E

    2005-06-01

    Ammonium (NH(4)(+)) concentrations in air and precipitation at the Institute of Ecosystem Studies (IES) in southeastern New York, USA declined over an 11-year period from 1988 to 1999, but increased from 1999 to 2001. These trends in particulate NH(4)(+) correlated well with trends in particulate SO(4)(2-) over the 1988-2001 period. The NH(4)(+) trends were not as well correlated with local cattle and milk production, which declined continuously throughout the period. This suggests that regional transport of SO(4)(2-) may have a greater impact on concentrations of NH(4)(+) and subsequent deposition than local agricultural emissions of NH(3). Ammonium concentrations in precipitation correlated significantly with precipitation SO(4)(2-) concentrations for the 1984-2001 period although NH(4)(+) in precipitation increased after 1999 and SO(4)(2-) in precipitation continued to decline after 1999. The correlation between NH(4)(+) and SO(4)(2-) was stronger for particulates than for precipitation. Particulate NH(4)(+) concentrations were also correlated with particulate SO(4)(2-) concentrations at 31 of 35 eastern U.S. CASTNet sites that had at least 10 years of data. Air concentrations of NH(4)(+) and SO(4)(2-) were more strongly correlated at the sites that were located within an agricultural landscape than in forested sites. At most of the sites there was either no trend or a decrease in NH(4)(+) dry deposition during the 1988-2001 period. The sites that showed an increasing trend in NH(4)(+) dry deposition were generally located in the southeastern U.S. The results of this study suggest that, in the northeastern U.S., air concentrations of NH(4)(+) and subsequent deposition may be more closely linked to SO(4)(2-) and thus SO(2) emissions than with NH(3) emissions. These results also suggest that reductions in S emissions have reduced NH(4)(+) transport to and NH(4)(+)-N deposition in the Northeast.

  1. Anaerobic ammonium oxidation in an estuarine sediment

    NARCIS (Netherlands)

    Risgaard-Petersen, N.; Meyer, R.L.; Schmid, M.C.; Jetten, M.S.M.; Enrich-Prast, A.; Rysgaard, S.; Revsbech, N.P.

    2004-01-01

    The occurrence and significance of the anammox (anaerobic ammonium oxidation) process relative to denitrification was studied in photosynthetically active sediment from 2 shallow-water estuaries: Randers Fjord and Norsminde Fjord, Denmark. Anammox accounted for 5 to 24 % of N-2 production in Randers

  2. Anaerobic ammonium oxidation in an estuarine sediment

    NARCIS (Netherlands)

    Risgaard-Petersen, N.; Meyer, R.L.; Schmid, M.; Jetten, M.S.M.; Enrich-Prast, A.; Rysgaard, S.; Revsbech, N.P.

    2004-01-01

    The occurrence and significance of the anammox (anaerobic ammonium oxidation) process relative to denitrification was studied in photosynthetically active sediment from 2 shallow-water estuaries: Randers Fjord and Norsminde Fjord, Denmark. Anammox accounted for 5 to 24% of N2 production in Randers

  3. 21 CFR 558.340 - Maduramicin ammonium.

    Science.gov (United States)

    2010-04-01

    .... Feed continuously as sole ration. Do not feed to laying hens. Withdraw 5 days before slaughter. (2... DRUGS, FEEDS, AND RELATED PRODUCTS NEW ANIMAL DRUGS FOR USE IN ANIMAL FEEDS Specific New Animal Drugs for Use in Animal Feeds § 558.340 Maduramicin ammonium. (a) Approvals. Type A medicated articles: 4.54...

  4. Lectin status, protein contents and ammonium assimilating ...

    African Journals Online (AJOL)

    activity of the ammonium assimilatory enzyme glutamine synthetase. M. nigra and M. alba extracts contained potent phytoagglutinins in various tissues with highest contents in M. nigra. The leaves and roots of both species of mulberry were used to determine the glutamine synthetase activity and high level of activity was ...

  5. Ammonium ions determination with polypyrrole modified electrode

    Directory of Open Access Journals (Sweden)

    Luiz Henrique Dall´Antonia

    2007-03-01

    Full Text Available The present work relates the preparation of polypyrrole films (PPy deposited on surfaces of glass carbon, nickel and ITO (tin oxide doped with indium on PET plastic, in order to study the ammonium detection. The popypyrrole films were polymerized with dodecylbenzenesulfonate (DBSA on the electrodes, at + 0,70 V vs. Ag/AgCl, based on a solution containing the pyrrole monomer and the amphiphilic salt. Films deposited on glass carbon presented better performance. Cyclic voltammetries, between – 1,50 to + 0,5 V vs. Ag/AgCl, were repeated adding different concentrations of NH4Cl, in order to observe the behavior of the film as a possible detector of ions NH4+. The peak current for oxidation varies with the concentration of ammonium. A linear region can be observed in the band of 0 to 80 mM, with a sensibility (Sppy approximately similar to 4,2 mA mM-1 cm-2, showing the efficacy of the electrodes as sensors of ammonium ions. The amount of deposited polymer, controlled by the time of growth, does not influence on the sensor sensibility. The modified electrode was used to determine ammonium in grounded waters.

  6. Ammonium conversion in liquid organic fertilisers

    NARCIS (Netherlands)

    Blok, C.; Streminska, M.; Vermeulen, T.

    2017-01-01

    Liquid organic fertilisers allow growers to abandon the use of conventional de novo (mined or synthesised) fertilisers without major technological adaptions to the cultivation system. In prior experiments the conversion by aerobic substrate born bacteria of ammonium into nitrate was plant growth

  7. Effects of ammonium nitrate, cesium chloride and ...

    African Journals Online (AJOL)

    Jane

    2011-10-12

    Oct 12, 2011 ... Key words: Potassium, high affinity transporters, channel blockers, ammonium. .... channel AtAKT1, indicating that channels may be involved in high-affinity. K+ uptake in a range of K+ concentrations (Hirsch et al.,. 1998; Spalding et al., ...... and tissue potassium concentrations by negative feedback effects.

  8. 21 CFR 184.1135 - Ammonium bicarbonate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium bicarbonate. 184.1135 Section 184.1135 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS § 18...

  9. Optimization of nutritional requirements and ammonium feeding ...

    African Journals Online (AJOL)

    Through Plackett-Burman design, the major factors of glucose, ammonium sulfate and KCl were selected as the significant factors affecting vitamin B12 biosynthesis and these were further optimized by central composite design with response surface methodology. The maximum Yp of 34.2 μg/gDCW/h was obtained in batch ...

  10. Effect of Ethylenediaminetetraacetic Acid and Ammonium Oxalate ...

    African Journals Online (AJOL)

    This research was carried out to investigate effect of ethylenediaminetetraacetic acid and ammonium oxalate on the prevalence of microorganisms and removal of aluminum in soil by bitter leaf plant (Vernonia amygdalina). The test plant was sown in aluminium-polluted soil (conc. = 150mg Al kg-1 soil). One gram of each ...

  11. PRN 88-2: Clustering of Quaternary Ammonium Compounds

    Science.gov (United States)

    This Notice announces that EPA has clustered the Quaternary Ammonium Compounds into four groups for the purpose of testing chemicals to build a database that will support continued registration of the entire family of quaternary ammonium compounds

  12. A differential protein solubility approach for the depletion of highly abundant proteins in plasma using ammonium sulfate.

    Science.gov (United States)

    Bollineni, Ravi Chand; Guldvik, Ingrid J; Grönberg, Henrik; Wiklund, Fredrik; Mills, Ian G; Thiede, Bernd

    2015-12-21

    Depletion of highly abundant proteins is an approved step in blood plasma analysis by mass spectrometry (MS). In this study, we explored a precipitation and differential protein solubility approach as a fractionation strategy for abundant protein removal from plasma. Total proteins from plasma were precipitated with 90% saturated ammonium sulfate, followed by differential solubilization in 55% and 35% saturated ammonium sulfate solutions. Using a four hour liquid chromatography (LC) gradient and an LTQ-Orbitrap XL mass spectrometer, a total of 167 and 224 proteins were identified from the 55% and 35% ammonium sulfate fractions, whereas 235 proteins were found in the remaining protein fractions with at least two unique peptides. SDS-PAGE and exclusive total spectrum counts from LC-MS/MS analyses clearly showed that majority of the abundant plasma proteins were solubilized in 55% and 35% ammonium sulfate solutions, indicating that the remaining protein fraction is of potential interest for identification of less abundant plasma proteins. Serum albumin, serotransferrin, alpha-1-antitrypsin and transthyretin were the abundant proteins that were highly enriched in 55% ammonium sulfate fractions. Immunoglobulins, complement system proteins, and apolipoproteins were among other abundant plasma proteins that were enriched in 35% ammonium sulfate fractions. In the remaining protein fractions a total of 40 unique proteins were identified of which, 32 proteins were identified with at least 10 exclusive spectrum counts. According to PeptideAtlas, 9 of these 32 proteins were estimated to be present at low μg ml(-1) (0.12-1.9 μg ml(-1)) concentrations in the plasma, and 17 at low ng ml(-1) (0.1-55 ng ml(-1)) range.

  13. Uptake and accumulation of ammonium by Alexandrium catenella ...

    African Journals Online (AJOL)

    Following nitrogen exhaustion from the medium, ammonium pulses of varying magnitudes were induced, and measurements of extra- and intra-cellular ammonium were carried out for 24–72h along with measurements of ammonium incorporation (15N tracer) and inorganic carbon fixation (13C tracer). During vegetative ...

  14. Spectrometric determination of ammonium-nitrogen with quinol in ...

    African Journals Online (AJOL)

    Quinol is proposed as a reagent for the spectrometric determination of ammonium-nitrogen (NH4+-N) in aqueous medium. Quinol forms a pink complex with ammonium salt in aqueous medium. Hydrogen peroxide is needed for colour accentuation. The quinol/ammonium charge transfer complex has absorption maximum ...

  15. 21 CFR 582.1127 - Aluminum ammonium sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Aluminum ammonium sulfate. 582.1127 Section 582.1127 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions of...

  16. 21 CFR 182.1127 - Aluminum ammonium sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Aluminum ammonium sulfate. 182.1127 Section 182.1127 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b...

  17. Modeling the Performance of Biological Rapid Sand Filters Used to Remove Ammonium, Iron, and Manganese From Drinking Water

    DEFF Research Database (Denmark)

    Lee, Carson; Albrechtsen, Hans-Jørgen; Smets, Barth F.

    activated carbon and are often used following ozonation to remove additional biodegradable organics created during ozonation. In Europe, biological filters are also used to remove ammonium and reduced forms of iron and manganese. These compounds can cause biological instability in the distribution system...... for chlorine addition following treatment. Under the normal conditions found in many water treatment plants, reduced iron can be oxidized through aeration and the precipitates can be captured by the filter media. Ammonium and manganese can be removed biologically. This research uses both pilot and full scale...... studies to determine how operating conditions affect the performance of the filters. Substrate concentrations, particle/precipitate accumulation, and biomass kinetics are monitored throughout the depth of the filter and over the operational cycle of the filter. Tracer tests, using a conservative salt...

  18. Detonation Properties of Ammonium Dinitramide (ADN)

    Science.gov (United States)

    Wätterstam, A.; Östmark, H.; Helte, A.; Karlsson, S.

    1999-06-01

    Ammonium Dinitramide, ADN, has a potential as an oxidizer for underwater high explosives. Pure ADN has a large reaction-zone length and shows a strong non-ideal behaviour. The work presented here is an extension of previous work.(Sensitivity and Performance Characterization of Ammonium Dinitramide (ADN). Presented at 11th International Detonation Symposium, Snowmass, CO, 1998.) Experiments for determining the detonation velocity as a function of inverse charge radius and density, reaction-zone length and curvature, and the detonation pressure are presented. Measurements of pressure indicates that no, or weak von-Neumann spike exists, suggesting an immediate chemical decomposition. Experimental data are compared with predicted using thermochemical codes and ZND-theory.

  19. Anaerobic ammonium oxidation in an estuarine sediment

    OpenAIRE

    Risgaard-Petersen, N.; Meyer, R.L.; Schmid, M.C.; Jetten, M.S.M.; Enrich-Prast, A.; Rysgaard, S.; Revsbech, N.P.

    2004-01-01

    The occurrence and significance of the anammox (anaerobic ammonium oxidation) process relative to denitrification was studied in photosynthetically active sediment from 2 shallow-water estuaries: Randers Fjord and Norsminde Fjord, Denmark. Anammox accounted for 5 to 24 % of N-2 production in Randers Fjord sediment, whereas no indication was seen of the process in sediment from Norsminde Fjord, It is suggested that the presence of anammox in Randers Fjord and its absence from Norsminde Fjord i...

  20. Optical constants of concentrated aqueous ammonium sulfate.

    Science.gov (United States)

    Remsberg, E. E.

    1973-01-01

    Using experimental data obtained from applying spectroscopy to a 39-wt-% aqueous ammonium sulfate solution, it is shown that, even though specific aerosol optical constants appear quite accurate, spectral variations may exist as functions of material composition or concentration or both. Prudent users of optical constant data must then include liberal data error estimates when performing calculations or in interpreting spectroscopic surveys of collected aerosol material.

  1. Proton dynamics investigation for dimethyl ammonium cation

    International Nuclear Information System (INIS)

    Pislewski, N.; Tritt-Goc, J.; Jakubas, R.

    1995-01-01

    Proton dynamics in dimethyl ammonium cation has been investigated by means of NMR and spin echo methods in polycrystalline salts [NH 2 (CH 3 ) 2 ] + Bi 2 J 9 - and [NH 2 (CH 3 ) 2 ] + SbJ 9 - . Spin-lattice relaxation time as well as second moment of NMR line have been measured for influence study of crystal structure changes on proton dynamics

  2. Equation of State of Ammonium Nitrate

    Science.gov (United States)

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

    2009-12-01

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

  3. Microbial electricity driven anoxic ammonium removal.

    Science.gov (United States)

    Vilajeliu-Pons, Anna; Koch, Christin; Balaguer, Maria D; Colprim, Jesús; Harnisch, Falk; Puig, Sebastià

    2018-03-01

    Removal of nitrogen, mainly in form of ammonium (NH 4 + ), in wastewater treatment plants (WWTPs) is a highly energy demanding process, mainly due to aeration. It causes costs of about half a million Euros per year in an average European WWTP. Alternative, more economical technologies for the removal of nitrogen compounds from wastewater are required. This study proves the complete anoxic conversion of ammonium (NH 4 + ) to dinitrogen gas (N 2 ) in continuously operated bioelectrochemical systems at the litre-scale. The removal rate is comparable to conventional WWTPs with 35 ± 10 g N m -3 d -1 with low accumulation of NO 2 - , NO 3 - , N 2 O. In contrast to classical aerobic nitrification, the energy consumption is considerable lower (1.16 ± 0.21 kWh kg -1 N, being more than 35 times less than for the conventional wastewater treatment). Biotic and abiotic control experiments confirmed that the anoxic nitrification was an electrochemical biological process mainly performed by Nitrosomonas with hydroxylamine as the main substrate (mid-point potential, E ox  = +0.67 ± 0.08 V vs. SHE). This article proves the technical feasibility and reduction of costs for ammonium removal from wastewater, investigates the underlying mechanisms and discusses future engineering needs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Study on effect of process parameters and mixing on morphology of ammonium diuranate

    International Nuclear Information System (INIS)

    Subhankar Manna; Chandrabhanu Basak; Thakkar, U.R.; Shital Thakur; Roy, S.B.; Joshi, J.B.; Institute of Chemical Technology, Matunga, Mumbai

    2016-01-01

    Ammonium diuranate (ADU) is an important intermediate for the production of uranium base fuel. Controlling morphology of crystalline ADU powders is very important as it is retained by its subsequent products. Because of the high level of supersaturation, the involved mechanisms of precipitation like primary nucleation, crystal growth, aggregation and breakage occur simultaneously and they control the morphology. Effects of concentration of uranyl nitrate solution, temperature and the mixing intensity have been investigated on the morphology, crystal structure and the other physical properties of ADU. Effect of temperature is found to be more dominant for controlling morphology. (author)

  5. Evaluation of operational parameters on the precipitation of endoglucanase and xylanase produced by solid state fermentation of Aspergillus niger

    Directory of Open Access Journals (Sweden)

    C. S. Farinas

    2011-03-01

    Full Text Available In order to develop cost effective processes for converting biomass into biofuels, it is essential to improve enzyme production yields, stability and specific activity. In this context, the aim of this work was to evaluate the concentration of two enzymes involved in the hydrolysis of biomass, endoglucanase and xylanase, through precipitation. Statistical experimental design was used to evaluate the influence of precipitant agent concentration (ammonium sulfate and ethanol, aging time, and temperature on enzyme activity recovery. Precipitant agent concentration and aging time showed a statistically significant effect at the 95% confidence level, on both enzyme activity recoveries. The recovery of endoglucanase with ammonium sulfate and ethanol reached values up to 65 and 61%, respectively. For xylanase, the recovery rates were lower, 27 and 25% with ammonium sulfate and ethanol, respectively. The results obtained allowed the selection of the variables relevant to improving enzyme activity recovery within operational conditions suitable for industrial applications.

  6. Decomposition of aluminum oxide, titanium(IV) oxide and niobium(V) oxide by fusion with ammonium sulfate

    International Nuclear Information System (INIS)

    Hashiba, Minoru; Miura, Eiji; Nurishi, Yukio; Hibino, Taizo

    1980-01-01

    A decomposition method with ammonium sulfate for Al 2 O 3 , TiO 2 and Nb 2 O 5 is presented. Al 2 O 3 and TiO 2 were fused at 400 and 450 0 C, for 2 h and 1 h, respectively, in the presence of ammonium sulfate (oxide/ammonium sulfate = 1/20 in weight). The fused products were dissolved and extracted into 4N H 2 SO 4 aqueous solution by warming on the water bath or gently boiling on asbestos. The degree of decomposition by fusion was confirmed from the amount of the oxides recovered in the following manner; with the aid of filter pulp, the residue was completely separated by filtration and washed thoroughly by hot water. To the filtrate was added ammonia water in order to precipitate aluminum and titanium hydroxide. The precipitates were ignited in platinum crucible at 1000 0 C and weighed in oxide form. Nb 2 O 5 was fused at 400 0 C for 1 h in the presence of ammonium sulfate (niobium pentoxide/ammonium sulfate = 1/10 in weight). The fused product was extracted with 20% tartaric acid aqueous solution. The degree of decomposition by fusion was confirmed from the amount of the oxide recovered as follows; after separation of the residue by a filter paper with the aid of filter pulp and washed thoroughly by 2% tartaric acid aqueous solution, freshly prepared 6% aqueous solution of cupferron was added to the filtrate and the precipitate formed was filtered immediately. The precipitate was ignited in platinum crucible at 1000 0 C and weighed as Nb 2 O 5 . The recovery of Al 2 O 3 , TiO 2 and Nb 2 O 5 by the present method was (99.2 +- 0.4), (100.1 +- 0.2) and (100.1 +- 0.2)%, respectively. It is concluded that Al 2 O 3 , TiO 2 and Nb 2 O 5 could be completely decomposed with ammonium sulfate. (author)

  7. Levels of ammonium, sulfate, chloride, calcium, and sodium in snow and ice from southern Greenland

    International Nuclear Information System (INIS)

    Busenberg, E.; Langway, C.C. Jr.

    1979-01-01

    Chemical analysis of surface snows and dated ice core samples from Dye 3, Greenland, suggests that the ammonium cation is a major constituent in all samples and that the annual ammonium levels present in the south Greenland samples have varied from 3.3 to 26.3 μg/kg between the seventeenth century and the present time. The annual range of 1974--1975 surface samples was between 3.8 and 8.8 μg/kg, while the mean was 5.7 +- 1.8 μ/kg. The recent large-scale uses of fixed nitrogen fertilizers and industrial pollution have apparently not affected the levels of ammonia reaching southern Greenland. The sodium and chloride present are predominantly derived from ocean spray, while more than 90% of the calcium is of continental origin. The levels of these three elements have not apparently been affected by human activity since the industrial revolution. Sulfate levels have increased dramatically since the industrial revolution, suggesting that sulfate of anthropogenic origin is the most important source of sulfate in modern snows from southern Greenland. The amount of the sulfuric acid neutralized by the ammonium cations was approximately 100% in the seventeenth and eighteenth centuries, dropping to approximately 20% in the 1974--1975 samples. These figures imply that there has been in increase in the acidity of precipitation in southern Greenland since the end of the eighteenth ce

  8. ISLSCP II Global Precipitation Climatology Project Version 1, Pentad Precipitation

    Data.gov (United States)

    National Aeronautics and Space Administration — The Global Precipitation Climatology Project (GPCP) pentad version 1 precipitation data set includes global precipitation rates for 5-day, or pentad, periods. The...

  9. [Achievement of Sulfate-Reducing Anaerobic Ammonium Oxidation Reactor Started with Nitrate-Reducting Anaerobic Ammonium Oxidation].

    Science.gov (United States)

    Liu, Zheng-chuan; Yuan, Lin-jiang; Zhou, Guo-biao; Li, Jing

    2015-09-01

    The transformation of nitrite-reducing anaerobic ammonium oxidation to sulfate-reducing anaerobic ammonium oxidation in an UASB was performed and the changes in microbial community were studied. The result showed that the sulfate reducing anaerobic ammonium oxidation process was successfully accomplished after 177 days' operation. The removal rate of ammonium nitrogen and sulfate were up to 58. 9% and 15. 7%, the removing load of ammonium nitrogen and sulfate were 74. 3 mg.(L.d)-1 and 77. 5 mg.(L.d)-1 while concentration of ammonium nitrogen and sulfate of influent were 130 mg.(L.d)-1 and 500 mg.(L.d)-1, respectively. The lost nitrogen and sulphur was around 2 in molar ratio. The pH value of the effluent was lower than that of the influent. Instead of Candidatus brocadia in nitrite reducing anaerobic ammonium oxidation granular sludge, Bacillus benzoevorans became the dominant species in sulfate reducing anaerobic ammonium oxidation sludge. The dominant bacterium in the two kinds of anaerobic ammonium oxidation process is different. Our results imply that the two anaerobic ammonium oxidation processes are carried out by different kind of bacterium.

  10. ISLSCP II Global Precipitation Climatology Project Version 2, Monthly Precipitation

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: The Global Precipitation Climatology Project (GPCP) Version 2 data set includes global, monthly precipitation rates and associated random errors (RMSE),...

  11. WPA Precipitation Tabulations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hourly precipitation data tabulated under the Work Projects Administration (WPA), a New Deal program created to reduce unemployment during the Great Depression....

  12. Ammonium dichromate poisoning: A rare cause of acute kidney injury

    Directory of Open Access Journals (Sweden)

    H Radhakrishnan

    2014-01-01

    Full Text Available Ammonium dichromate is an inorganic compound frequently used in screen and color printing. Being a strong oxidizing agent, it causes oxygen free radical injury resulting in organ failure. We report a 25-year-old female who presented with acute kidney injury after consumption of ammonium dichromate. She was managed successfully with hemodialysis and supportive measures. This case is reported to highlight the toxicity of ammonium dichromate.

  13. Quaternary Ammonium Polyethyleneimine: Antibacterial Activity Ira

    International Nuclear Information System (INIS)

    Farber, Y.; Domb, A.G.; Golenser, J.; Beyth, N.; Weiss, E.I.

    2010-01-01

    Quaternary ammonium polyethyleneimine- (QA-PEI-) based nanoparticles were synthesized using two synthetic methods, reductive amination and N-alkylation. According to the first method, QA-PEI nanoparticles were synthesized by cross-linking with glutaraldehyde followed by reductive amination with octanal and further N-methylation with methyl iodide. The second method is based on crosslinking with dialkyl halide followed by N-alkylation with octyl halide and further N-methylation with methyl iodide. QA-PEI nanoparticles completely inhibited bacterial growth (>106 bacteria), including both Gram-positive, that is, Staphylococcus aureus at 80 μ/mL, and Gram-negative, that is, Escherichia coli at 320 μ/mL. Activity analysis revealed that the degree of alkylation and N-methylation of the QA-PEI nanoparticles plays a significant role in antibacterial activity of the reagent. The most potent compound was octyl alkylated QA-PEI alkylated at 1 : 1 mole ratio (primary amine of PEI monomer units/alkylating agent). Also, cytotoxicity studies on MAT-LyLu and MBT cell lines were performed with QA-PEI nanoparticles. These findings confirm previous reports that poly cations bearing quaternary ammonium moieties inhibit bacterial growth in vitro and have a potential use as additives in medical devices which need antibacterial properties.

  14. Effects of environmental factors on microbial induced calcium carbonate precipitation.

    Science.gov (United States)

    Mortensen, B M; Haber, M J; DeJong, J T; Caslake, L F; Nelson, D C

    2011-08-01

    To gain an understanding of the environmental factors that affect the growth of the bacterium Sporosarcina pasteurii, the metabolism of the bacterium and the calcium carbonate precipitation induced by this bacterium to optimally implement the biological treatment process, microbial induced calcium carbonate precipitation (MICP), in situ. Soil column and batch tests were used to assess the effect of likely subsurface environmental factors on the MICP treatment process. Microbial growth and mineral precipitation were evaluated in freshwater and seawater. Environmental conditions that may influence the ureolytic activity of the bacteria, such as ammonium concentration and oxygen availability, as well as the ureolytic activities of viable and lysed cells were assessed. Treatment formulation and injection rate, as well as soil particle characteristics are other factors that were evaluated for impact on uniform induction of cementation within the soils. The results of the study presented herein indicate that the biological treatment process is equally robust over a wide range of soil types, concentrations of ammonium chloride and salinities ranging from distilled water to full seawater; on the time scale of an hour, it is not diminished by the absence of oxygen or lysis of cells containing the urease enzyme. This study advances the biological treatment process MICP towards field implementation by addressing key environmental hurdles faced with during the upscaling process. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.

  15. Ammonium Production in Sediments Inhibited with Molybdate: Implications for the Sources of Ammonium in Anoxic Marine Sediments †

    OpenAIRE

    Jacobson, Myrna E.; Mackin, James E.; Capone, Douglas G.

    1987-01-01

    Ammonium production in the presence of specific inhibitors of sulfate reduction and methanogenesis was investigated in six marine sediments which differed in bulk properties and organic matter input. In all cases, little effect of the inhibitors on ammonium production was observed, although sulfate reduction was suppressed by molybdate. This gives evidence that the processes of fermentation and hydrolysis are of primary importance in ammonium generation at the sites studied. Although sulfate ...

  16. Tracking lysozyme unfolding during salt-induced precipitation with hydrogen exchange and mass spectrometry.

    Science.gov (United States)

    Tobler, S A; Sherman, N E; Fernandez, E J

    We utilized electrospray ionization mass spectrometry (ESI-MS) and hydrogen-deuterium exchange (HX) to detect unfolding of hen egg white lysozyme during salt-induced precipitation. Deuterated lysozyme was dissolved in protonated buffer at pH 2.16 and precipitated with ammonium sulfate, sodium chloride, and potassium thiocyanate. ESI-MS was used to detect mass differences in lysozyme due to the loss of deuterons for solvent protons, providing insight on the conformational history of the protein during the labeling experiment. Precipitation with ammonium sulfate and sodium chloride did not unfold lysozyme, consistent with the known stabilizing effects of kosmotropic salts. Potassium thiocyanate, an aggressive chaotrope, was an effective precipitant at 0.2 M, but also disrupted lysozyme structure and caused the formation of precipitate fractions that did not readily redissolve into aqueous solution without the use of a chemical denaturant. Precipitation with 1.0 M thiocyanate resulted in faster rates of unfolding and larger amounts of the insoluble precipitate. The unfolding kinetics were biphasic, exhibiting a slow phase after a few hours that presumably reflected a smaller propensity for lysozyme to unfold in the precipitated state. Bimodal mass distributions in the ESI-MS spectra for the thiocyanate precipitates indicate two states for lysozyme in this system, a native and a molten globule-like partially unfolded state. ESI-MS analysis of the insoluble precipitates indicated that they consisted primarily of protein molecules that had unfolded. Investigation of the HX behavior of lysozyme in a KSCN solution at low protein concentrations confirmed the destabilizing effect of the salt on the protein structure, even when there was almost no solid phase present. The HX/ESI-MS results provide insight into the mechanism combining precipitation and denaturation for such a system, both in terms of obtaining quantitative kinetic and stability information and the

  17. Lectin status, protein contents and ammonium assimilating ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-11-16

    Nov 16, 2009 ... certain types of tumor cells and precipitation of certain polysaccharides and glycoproteins (Lis and Sharon,. 1986; Goldstein and Hayes, 1978). .... min by the addition of 1 ml of 3-3% (w/v) FeCl, 8% (w/v) TCA in 2 N. HCl and the glutamine synthetase activity is measured spectropho- tometrically at 540 nm by ...

  18. Efficient cellulose solvent: quaternary ammonium chlorides.

    Science.gov (United States)

    Kostag, Marc; Liebert, Tim; El Seoud, Omar A; Heinze, Thomas

    2013-10-01

    Pure quaternary tetraalkylammonium chlorides with one long alkyl chain dissolved in various organic solvents constitute a new class of cellulose solvents. The electrolytes are prepared in high yields and purity by Menshutkin quaternization, an inexpensive and easy synthesis route. The pure molten tetraalkylammonium chlorides dissolve up to 15 wt% of cellulose. Cosolvents, including N,N-dimethylacetamide (DMA), may be added in large excess, leading to a system of decreased viscosity. Contrary to the well-established solvent DMA/LiCl, cellulose dissolves in DMA/quaternary ammonium chlorides without any pretreatment. Thus, the use of the new solvent avoids some disadvantages of DMA/LiCl and ionic liquids, the most extensively employed solvents for homogeneous cellulose chemistry. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Hydration Structure of the Quaternary Ammonium Cations

    KAUST Repository

    Babiaczyk, Wojtek Iwo

    2010-11-25

    Two indicators of the hydropathicity of small solutes are introduced and tested by molecular dynamics simulations. These indicators are defined as probabilities of the orientation of water molecules\\' dipoles and hydrogen bond vectors, conditional on a generalized distance from the solute suitable for arbitrarily shaped molecules. Using conditional probabilities, it is possible to distinguish features of the distributions in close proximity of the solute. These regions contain the most significant information on the hydration structure but cannot be adequately represented by using, as is usually done, joint distance-angle probability densities. Our calculations show that using our indicators a relative hydropathicity scale for the interesting test set of the quaternary ammonium cations can be roughly determined. © 2010 American Chemical Society.

  20. Double selenates of rare earths and ammonium

    International Nuclear Information System (INIS)

    Iskhakova, L.D.; Kozlova, N.P.; Makarevich, L.G.

    1991-01-01

    Double selenates of rare earths with ammonium were prepared in result of crystallization. It is shown that NH 4 Ln(SeO 4 ) · nH 2 O crystalline hydrates are presented by penta-and trihydrates. Existance of two modifications was revealed for NH 4 Ln(SeO 4 ) · 5H 2 O: monoclinic form of NH 4 La(SeO 4 ) 2 · 5H 2 O, isostructural RbCe(SeO 4 ) 2 · 5H 2 O, and earlier unknown rhombic form of salts with Ln = Pr, Nd. Trihydrates with Ln = Sm-Yb belong to structural type of RbNd(SeO 4 ) 2 · 3H 2 O. Anhydrous salts NH 4 Ln(SeO 4 ) 2 are isostructural with monoclinic KNd(SO 4 ) 2 modification. Lattice parameters of binary selenates are presented

  1. 21 CFR 184.1296 - Ferric ammonium citrate.

    Science.gov (United States)

    2010-04-01

    ... occurs as thin transparent green scales, as granules, as a powder, or as transparent green crystals. (b) The ingredients meet the specifications of the Food Chemicals Codex, 3d Ed. (1981), pp. 116-117 (Ferric ammonium citrate, brown) and p. 117 (Ferric ammonium citrate, green), which is incorporated by...

  2. Ammonium removal from aqueous solution by ion-exchange using ...

    African Journals Online (AJOL)

    Ammonium removal from aqueous solution by a natural ion-exchange resin was investigated by considering the factors affecting the ammonium-exchange capacity including the zeolites' particle size, the loading flow rates and the impact of a number of regenerations upon the ion-exchange capacity. The resin column was ...

  3. 21 CFR 172.165 - Quaternary ammonium chloride combination.

    Science.gov (United States)

    2010-04-01

    ... HUMAN CONSUMPTION Food Preservatives § 172.165 Quaternary ammonium chloride combination. The food... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Quaternary ammonium chloride combination. 172.165 Section 172.165 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES...

  4. Modelling nitrogen assimilation of Escherichia coli at low ammonium concentration.

    NARCIS (Netherlands)

    Ma, H.; Boogerd, F.C.; Goryanin, I.

    2009-01-01

    Modelling is an important methodology in systems biology research. In this paper, we presented a kinetic model for the complex ammonium assimilation regulation system of Escherichia coli. Based on a previously published model, the new model included AmtB mediated ammonium transport and AmtB

  5. Ginger-supplemented diet ameliorates ammonium nitrate-induced ...

    African Journals Online (AJOL)

    The present study was designed to evaluate the capacity of ginger to repair the oxidative stress induced by ammonium nitrate. 50 male rats were divided into 5 groups; they underwent an oral treatment of ammonium nitrate and/or ginger (N mg/kg body weight + G% in diet) during 30 days. Group I served as control (C); ...

  6. Studies on the Effects of Ammonium Phosphates on the ...

    African Journals Online (AJOL)

    ……..(2). Ammonium dihydrogen tetraoxophosphate (V): (NH4)2HPO4 → NH4H2PO4 + NH3 ……(3a). NH4H2PO4 → H3PO4 + NH3 …...........(3b). Scheme 1: Equations for the combustion of the three ammonium phosphates used in filling the ...

  7. Thiourea-doped ammonium dihydrogen phosphate: A single crystal ...

    Indian Academy of Sciences (India)

    Thiourea-doped ammonium dihydrogen phosphate (TADP) exhibits nonlinear optical property and the second harmonic generation efficiency of these crystals is three times that of pure ammonium dihydrogen phosphate (ADP) crystal. In this context, the study of structural distortion in the thiourea-doped ADP crystal is ...

  8. 78 FR 32690 - Certain Ammonium Nitrate From Ukraine

    Science.gov (United States)

    2013-05-31

    ... From Ukraine Determination On the basis of the record \\1\\ developed in the subject five-year review... certain ammonium nitrate from Ukraine would be likely to lead to continuation or recurrence of material... Ammonium Nitrate from Ukraine: Investigation No. 731-TA-894 (Second Review). By order of the Commission...

  9. The Rh complex exports ammonium from human red blood cells

    NARCIS (Netherlands)

    Hemker, Mirte B.; Cheroutre, Goedele; van Zwieten, Rob; Maaskant-van Wijk, Petra A.; Roos, Dirk; Loos, Johannes A.; van der Schoot, C. Ellen; von dem Borne, Albert E. G. Kr

    2003-01-01

    The Rh blood group system represents a major immunodominant protein complex on red blood cells (RBC). Recently, the Rh homologues RhAG and RhCG were shown to promote ammonium ion transport in yeast. In this study, we showed that also in RBC the human Rh complex functions as an exporter of ammonium

  10. Synthesis, antimicrobial activity of lamotrigine and its ammonium ...

    Indian Academy of Sciences (India)

    Antiepileptic drug lamotrigine and its thirteen ammonium salt complexes (4a-4m) were synthesized and characterized by IR, elemental analysis, 1H-NMR, and MS spectral methods. Many of the ammonium salts (4a-4m) were first reported. Furthermore, the crystal structure of compound 3 was determined by single crystal ...

  11. Ceric ammonium nitrate catalysed three component one-pot efficient ...

    Indian Academy of Sciences (India)

    Wintec

    Abstract. Ceric ammonium nitrate (CAN) is used as an efficient catalyst for the synthesis of 2,4,5- triaryl-1H-imidazoles via condensation of benzoin/benzil, ammonium acetate, and aromatic aldehydes. The easy work-up, higher yields and shorter reaction time are the advantages of the method presented here. Keywords.

  12. Effects of dietary ammonium sulphate (AS) on the performance and ...

    African Journals Online (AJOL)

    Two experiments were designed to investigate the response of broilers to dietary inclusion of ammonium sulphate. In experiment 1, day old chicks were fed diets with 0,1,2 or 3 % ammonium sulphate (AS) during the starter phase (0 –4 weeks). In experiment 2, broilers chicks were raised on a standard diet from 0 – 4 weeks ...

  13. Ceric ammonium nitrate catalysed three component one-pot efficient ...

    Indian Academy of Sciences (India)

    Ceric ammonium nitrate (CAN) is used as an efficient catalyst for the synthesis of 2,4,5-triaryl-1H-imidazoles via condensation of benzoin/benzil, ammonium acetate, and aromatic aldehydes. The easy work-up, higher yields and shorter reaction time are the advantages of the method presented here.

  14. Extraction of uranium from seawater with magnesium hydroxide precipitate depositing from seawater

    International Nuclear Information System (INIS)

    Fujinaga, Taitiro; Kuwamoto, Tooru; Nakayama, Eiichiro; Isshiki, Kenji

    1984-01-01

    Magnesium hydroxide precipitate depositing from alkalized seawater was used as an adsorbent for the extraction of uranium from seawater. Calcium hydroxide was a suitable alkali because the adsorption of uranium was enhanced in the presence of calcium ion. Uranium was adsorbed quantitatively with magnesium hydroxide precipitate when an adequate amount of calcium hydroxide was added to precipitate 80 to 90 % of magnesium ion in seawater. More than 80 % of adsorbed uranium was eluted from the precipitate with 1 to 3 M ammonium carbonate solution, in which the precipitate was hardly dissolved at all. With this method about 11 mg of uranium was collected as uranyl salt from 6,000 l of natural seawater. The recovery throughout all processes was about 70 % (author)

  15. Shock wave synthesis of amino acids from solutions of ammonium formate and ammonium bicarbonate

    Science.gov (United States)

    Suzuki, Chizuka; Furukawa, Yoshihiro; Kobayashi, Takamichi; Sekine, Toshimori; Nakazawa, Hiromoto; Kakegawa, Takeshi

    2015-07-01

    The emergence of life's building blocks, such as amino acids and nucleobases, on the prebiotic Earth was a critical step for the beginning of life. Reduced species with low mass, such as ammonia, amines, or carboxylic acids, are potential precursors for these building blocks of life. These precursors may have been provided to the prebiotic ocean by carbonaceous chondrites and chemical reactions related to meteorite impacts on the early Earth. The impact of extraterrestrial objects on Earth occurred more frequently during this period than at present. Such impacts generated shock waves in the ocean, which have the potential to progress chemical reactions to form the building blocks of life from reduced species. To simulate shock-induced reactions in the prebiotic ocean, we conducted shock-recovery experiments on ammonium bicarbonate solution and ammonium formate solution at impact velocities ranging from 0.51 to 0.92 km/s. In the products from the ammonium formate solution, several amino acids (glycine, alanine, ß-alanine, and sarcosine) and aliphatic amines (methylamine, ethylamine, propylamine, and butylamine) were detected, although yields were less than 0.1 mol % of the formic acid reactant. From the ammonium bicarbonate solution, smaller amounts of glycine, methylamine, ethylamine, and propylamine were formed. The impact velocities used in this study represent minimum cases because natural meteorite impacts typically have higher velocities and longer durations. Our results therefore suggest that shock waves could have been involved in forming life's building blocks in the ocean of prebiotic Earth, and potentially in aquifers of other planets, satellites, and asteroids.

  16. Hybrid organic-inorganic crystals based on ammonium dihydrogen phosphate and ammonium salicylate

    Science.gov (United States)

    Voronov, A. P.; Salo, V. I.; Puzikov, V. M.; Babenko, G. N.; Roshal, A. D.; Tkachenko, V. F.

    2011-11-01

    ADP-NH 4Sal hybrid crystals are grown from aqueous solutions. The influence of the acidity of the mixed solution on the conditions of co-crystallization of the components is studied. The spectral and scintillation characteristics are determined. Co-crystallization of ammonium salicylate (NH 4Sal) and ammonium dihydrogen phosphate (ADP, NH 4H 2PO 4) is shown to be feasible, the structure of the doping addition being defined by the solution рН. In basic and weak acidic media the hybrid crystals ADP:NH 4Sal are formed in which salicylate anions are located in the interplanar space between the {110}-type planes in the lattice of ADP. The luminescence spectra contain an emission band maximum with λ max=360 nm. In acidic solutions there are ADP:HSal crystals in which salicylic acid molecules captured by the growth macrosteps are located in the interplanar space of the prismatic {100} and pyramidal {101} growth sectors. The luminescence band undergoes bathochromic shift to λmax=400 nm. The sensitivity of ADP:NH 4Sal scintillation crystals to fast neutrons depends on the concentration of ammonium salicylate in ADP matrix. The highest neutron sensitivity is characteristic of the co-doped ADP:NH 4Sal/Tl scintillation crystals.

  17. Ammonium removal using algae-bacteria consortia: the effect of ammonium concentration, algae biomass, and light.

    Science.gov (United States)

    Jia, Huijun; Yuan, Qiuyan

    2018-04-01

    In this study, the effects of ammonium nitrogen concentration, algae biomass concentration, and light conditions (wavelength and intensity) on the ammonium removal efficiency of algae-bacteria consortia from wastewater were investigated. The results indicated that ammonium concentration and light intensity had a significant impact on nitrification. It was found that the highest ammonia concentration (430 mg N/L) in the influent resulted in the highest ammonia removal rate of 108 ± 3.6 mg N/L/days, which was two times higher than the influent with low ammonia concentration (40 mg N/L). At the lowest light intensity of 1000 Lux, algae biomass concentration, light wavelength, and light cycle did not show a significant effect on the performance of algal-bacterial consortium. Furthermore, the ammonia removal rate was approximately 83 ± 1.0 mg N/L/days, which was up to 40% faster than at the light intensity of 2500 Lux. It was concluded that the algae-bacteria consortia can effectively remove nitrogen from wastewater and the removal performance can be stabilized and enhanced using the low light intensity of 1000 Lux that is also a cost-effective strategy.

  18. Reactive Uptake of Dimethylamine by Ammonium Sulfate and Ammonium Sulfate-Sucrose Mixed Particles.

    Science.gov (United States)

    Chu, Yangxi; Chan, Chak K

    2017-01-12

    Short-chain alkyl amines can undergo gas-to-particle partitioning via reactive uptake by ammonium salts, whose phases have been thought to largely influence the extent of amine uptake. Previous studies mainly focused on particles of single ammonium salt at either dry or wet conditions without any addition of organic compounds. Here we report the uptake of dimethylamine (DMA) by ammonium sulfate (AS) and AS-sucrose mixed particles at different relative humidities (RHs) using an electrodynamic balance coupled with in situ Raman spectroscopy. DMA is selected as a representative of short-chain alkyl amines, and sucrose is used as a surrogate of viscous and hydrophilic organics. Effective DMA uptake was observed for most cases, except for the water-limiting scenario at <5% RH and the formation of an ultraviscous sucrose coating at 10% RH and below. DMA uptake coefficients (γ) were estimated using the particle mass measurements during DMA uptake. Addition of sucrose can increase γ by absorbing water or inhibiting AS crystallization and decrease γ by elevating the particle viscosity and forming a coating layer. DMA uptake can be facilitated for crystalline AS or retarded for aqueous AS with hydrophilic viscous organics (e.g., secondary organic material formed via the oxidation of biogenic volatile organic compounds) present in aerosol particles.

  19. Precipitation Reconstruction (PREC)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The PREC data set is an analysis of monthly precipitation constructed on a 2.5(o)lat/lon grid over the global for the period from 1948 to the present. The land...

  20. Ion-selective solid-phase electrode sensitive to ammonium ions

    International Nuclear Information System (INIS)

    Vlasov, Yu.G.; Milonova, M.S.; Antonov, P.P.; Bychkov, E.A.; Ehfa, A.Ya.

    1983-01-01

    Ammonium phosphomolybdate is investigated for the purpose of using it as membrane material of ammonium-selective solid-phase electrodes. Estimation of proton mobility and ion conductivity of ammonium phosphomolybdate is performed

  1. Heavy metal immobilization via microbially induced carbonate precipitation and co-precipitation

    Science.gov (United States)

    Lauchnor, E. G.; Stoick, E.

    2017-12-01

    Microbially induced CaCO3 precipitation (MICP) has been successfully used in applications such as porous media consolidation and sealing of leakage pathways in the subsurface, and it has the potential to be used for remediation of metal and radionuclide contaminants in surface and groundwater. In this work, MICP is investigated for removal of dissolved heavy metals from contaminated mine discharge water via co-precipitation in CaCO3 or formation of other metal carbonates. The bacterially catalyzed hydrolysis of urea produces inorganic carbon and ammonium and increases pH and the saturation index of carbonate minerals to promote precipitation of CaCO3. Other heavy metal cations can be co-precipitated in CaCO3 as impurities or by replacing Ca2+ in the crystal lattice. We performed laboratory batch experiments of MICP in alkaline mine drainage sampled from an abandoned mine site in Montana and containing a mixture of heavy metals at near neutral pH. Both a model bacterium, Sporosarcina pasteurii, and a ureolytic bacterium isolated from sediments on the mine site were used to promote MICP. Removal of dissolved metals from the aqueous phase was determined via inductively coupled plasma mass spectrometry and resulting precipitates were analyzed via electron microscopy and energy dispersive x-ray spectroscopy (EDX). Both S. pasteurii and the native ureolytic isolate demonstrated ureolysis, increased the pH and promoted precipitation of CaCO3 in batch tests. MICP by the native bacterium reduced concentrations of the heavy metals zinc, copper, cadmium, nickel and manganese in the water. S. pasteurii was also able to promote MICP, but with less removal of dissolved metals. Analysis of precipitates revealed calcium carbonate and phosphate minerals were likely present. The native isolate is undergoing identification via 16S DNA sequencing. Ongoing work will evaluate biofilm formation and MICP by the isolate in continuous flow, gravel-filled laboratory columns. This research

  2. Analysis of ADU structure obtained under different precipitation conditions

    International Nuclear Information System (INIS)

    Ramella, Jose L.; Esteban, Adolfo; Mendez De Leo, Lucia P.; Sassone, Ariel; Novara, Oscar E.; Boero, Norma L.; Leyva, Ana G.

    1999-01-01

    ADU is the nominal name for ammonium poly uranate. It is a very complex compound of polymeric structure, which may have, according to precipitation conditions, different chemical composition and crystallographic structure. ADU is used as uranium oxide precursor in the manufacture of fuel elements. In former papers it was proved that if ultrasound is applied during precipitation and digestion the characteristics of the final product (U 3 O 8 UO 2 ) improve. By studying ADU thermal decomposition obtained by ultrasonic application, it was intended to obtain its composition. Therefore, differential thermal gravimetric and differential thermal analyses were performed. Samples were taken from special points and analyzed by X-ray diffraction, infra-red spectroscopy and scanning. An experiment was also designed to identify the products released during heating. Results and conclusions obtained are presented in this work. (author)

  3. Size-dependent reactions of ammonium bisulfate clusters with dimethylamine.

    Science.gov (United States)

    Bzdek, Bryan R; Ridge, Douglas P; Johnston, Murray V

    2010-11-04

    The reaction kinetics of ammonium bisulfate clusters with dimethylamine (DMA) gas were investigated using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). Clusters ranged in size from 1 to 10 bisulfate ions. Although displacement of the first several ammonium ions by DMA occurred with near unit efficiency, displacement of the final ammonium ion was cluster size dependent. For small clusters, all ammonium ions are exposed to incoming DMA molecules, allowing for facile exchange ("surface" exchange). However, with increasing cluster size, an ammonium ion can be trapped in an inaccessible region of the cluster ("core" exchange), thereby rendering exchange difficult. DMA was also observed to add onto existing dimethylaminium bisulfate clusters above a critical size, whereas ammonia did not add onto ammonium bisulfate clusters. The results suggest that as the cluster size increases, di-dimethylaminium sulfate formation becomes more favorable. The results of this study give further evidence to suggest that ambient sub-3 nm diameter particles are likely to contain aminium salts rather than ammonium salts.

  4. C18-COOH Silica: Preparation, Characterisation and Its Application in Purification of Quaternary Ammonium Alkaloids from Coptis chinensis.

    Science.gov (United States)

    Wang, Qing; Long, Yao; Yao, Lin; Ye, Mao; Xu, Li

    2017-07-01

    Traditional methods for isolating and purifying quaternary ammonium alkaloids from Coptis chinensis do not discriminate the target alkaloids from co-extractives. Mixed-mode analytical chromatography has the potential to improve the separation of analytes in more complex extracts and, when used in a solid-phase extraction mode, improve the purity of isolated compounds. To examine the high-performance liquid chromatographic separation capabilities of a mixed-mode, silica-based adsorbent and its application to the purification of quaternary ammonium alkaloids from Coptis chinensis based on solid-phase extraction. The C18-COOH silica was prepared via "thiol-ene" click chemistry. Its chromatographic performance was firstly investigated. It was employed as the solid-phase extraction sorbent to purify quaternary ammonium alkaloids. Hydrophobic, attractive/repulsive electrostatic and ion-exchange interactions were demonstrated to be the possible retention mechanisms of a C18-COOH silica stationary phase, which could separate analytes of various properties. In addition, to purify quaternary ammonium alkaloids from Coptis chinensis, the solid-phase extraction approach based on the C18-COOH silica provided a slightly higher purification efficiency (6.7%) than an alkaloid-salt precipitation protocol (5.3%). The method had satisfactory reproducibility, re-using the same solid-phase extraction column three times, with relative standard deviations ranging from 1.99% to 8.02% for the six target alkaloids. A multi-functionalised silica was synthesised via "click chemistry". As the high-performance liquid chromatographic stationary phase, the C18-COOH silica could be operated in trimodal reversed-phase/weak cation exchange/hydrophilic interaction mode. The C18-COOH silica also exhibited potential as solid-phase extraction sorbent in the purification of quaternary ammonium alkaloids from complex matrices. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons

  5. The creation of defects in ammonium halides by excitons

    International Nuclear Information System (INIS)

    Kim, L.M.

    2002-01-01

    The ammonium halides crystals and alkali halides crystals are analogous by kind chemical bonds and crystalline lattices. The anionic sublattice is identical in this crystals. It is known the main mechanism of defect creation by irradiation is radiationless decay of excitons in alkali halides crystals. The F-, H-centers are formation in this processes. However, F, H-centres are not detected in ammonium halides. The goal of this work is investigation the creation of defects in ammonium halides by excitons. We established that excitons in ammonium chlorides and bromides are similar to excitons in alkali halides. It is known excitons are self-trapped and have identical parameters of the exciton-phonon interaction in both kind crystals. It is supposed, that processes of radiationless disintegration of excitons are identical in ammonium and alkali halides. It is necessary to understand why F-, H-centers are absent in ammonium halides. V k -centres are created by the excitation of the ammonium halides crystals in the absorption band of excitons. It was established by thermoluminescence and spectrums of absorption. The V k -centers begin to migrate at 110-120 K in ammonium chlorides and bromides. The curve of thermoluminescence have peak with maximum at this temperatures. It is known V k -centers in ammonium chlorides have the absorption band at 380 nm. We discovered this absorption band after irradiation of crystals by ultra-violet. In alkali halides F-center is anionic vacancy with electron. The wave function of electron are spread ed at the cations around anionic vacancy. We established the cation NH 4 + in ammonium halides can to capture electron. The ion NH 4 2+ is unsteady. It is disintegrated to NH 3 + and H + . We suppose that excitons in ammonium and alkali halides are disintegrated identically. When cation NH 4 + capture electron, in the anionic sublattice the configuration are created in a direction (100) The indicated configuration is unsteady in relation to a

  6. Modelling an Ammonium Transporter with SCLS

    Directory of Open Access Journals (Sweden)

    Angelo Troina

    2009-10-01

    Full Text Available The Stochastic Calculus of Looping Sequences (SCLS is a recently proposed modelling language for the representation and simulation of biological systems behaviour. It has been designed with the aim of combining the simplicity of notation of rewrite systems with the advantage of compositionality. It also allows a rather simple and accurate description of biological membranes and their interactions with the environment.In this work we apply SCLS to model a newly discovered ammonium transporter. This transporter is believed to play a fundamental role for plant mineral acquisition, which takes place in the arbuscular mycorrhiza, the most wide-spread plant-fungus symbiosis on earth. Due to its potential application in agriculture this kind of symbiosis is one of the main focuses of the BioBITs project. In our experiments the passage of NH3 / NH4+ from the fungus to the plant has been dissected in known and hypothetical mechanisms; with the model so far we have been able to simulate the behaviour of the system under different conditions. Our simulations confirmed some of the latest experimental results about the LjAMT2;2 transporter. The initial simulation results of the modelling of the symbiosis process are promising and indicate new directions for biological investigations.

  7. Uranium concentrate obtained from sulfuric liquor by solvent extraction using ammonium sulfate as extractant agent; Obtencao de concentrado de uranio a partir de licor sulfurico por extracao por solventes utilizando sulfato de amonio como agente reextratante

    Energy Technology Data Exchange (ETDEWEB)

    Morais, Carlos Antonio de [Centro de Desenvolvimento de Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil)]. E-mail: cmorais@cdtn.br; Gomiero, Luiz Alberto [Industrias Nucleares do Brasil S.A. (INB), Caetite, BA (Brazil)]. E-mail: gomiero@inb.gov.br

    2005-07-01

    Results of uranium concentrate obtainment from sulfuric liquor by solvent extraction followed by chemical precipitation techniques are presented. In the extraction process a tertiary amine as extractant agent and ammonium sulfate solution as stripping agent were used. Uranium was precipitated from the pregnant strip solution as ammonium diuranate by addition of ammonium hydroxide solution. Equilibrium pH and chloride content in the loaded solvent were the main interference on the uranium stripping stage. From a chloride-free uranium loaded organic phase a pregnant strip solution containing 33.2 g/L U{sub 3}O{sub 8} and a stripped solvent with 0.006 g/L U{sub 3}O{sub 8} using 5 stages of mixer-settlers were obtained. The chemical precipitation stage yielded a high purity ammonium diuranate precipitate with a recovery of 99.98%. After calcination, the product presented 99.7 % U{sub 3}O{sub 8} content. (author)

  8. Hourly Precipitation Data (HPD) Publication

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hourly Precipitation Data (HPD) Publication is archived and available from the National Climatic Data Center (NCDC). This publication contains hourly precipitation...

  9. The precipitation of magnesium potassium phosphate hexahydrate for P and K recovery from synthetic urine.

    Science.gov (United States)

    Xu, Kangning; Li, Jiyun; Zheng, Min; Zhang, Chi; Xie, Tao; Wang, Chengwen

    2015-09-01

    Nutrients recovery from urine to close the nutrient loop is one of the most attractive benefits of source separation in wastewater management. The current study presents an investigation of the thermodynamic modeling of the recovery of P and K from synthetic urine via the precipitation of magnesium potassium phosphate hexahydrate (MPP). Experimental results show that maximum recovery efficiencies of P and K reached 99% and 33%, respectively, when the precipitation process was initiated only through adding dissolvable Mg compound source. pH level and molar ratio of Mg:P were key factors determining the nutrient recovery efficiencies. Precipitation equilibrium of MPP and magnesium sodium phosphate heptahydrate (MSP) was confirmed via precipitates analysis using a Scanning Electron Microscope/Energy Dispersive Spectrometer and an X-ray Diffractometer. Then, the standard solubility products of MPP and MSP in the synthetic urine were estimated to be 10(-12.2 ± 0.0.253) and 10(-11.6 ± 0.253), respectively. The thermodynamic model formulated on chemical software PHREEQC could well fit the experimental results via comparing the simulated and measured concentrations of K and P in equilibrium. Precipitation potentials of three struvite-type compounds were calculated through thermodynamic modeling. Magnesium ammonium phosphate hexahydrate (MAP) has a much higher tendency to precipitate than MPP and MSP in normal urine while MSP was the main inhibitor of MPP in ammonium-removed urine. To optimize the K recovery, ammonium should be removed prior as much as possible and an alternative alkaline compound should be explored for pH adjustment rather than NaOH. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Nitrogen concentrations in a small Mediterranean stream: 1. Nitrate 2. Ammonium

    Directory of Open Access Journals (Sweden)

    A. Butturini

    2002-01-01

    similar suggesting that stream ammonium concentrations are sustained mainly by input from groundwater. The present study provides evidence that storm flow magnitude is an important source of variability of nitrate concentration and fluxes in Mediterranean streams subjected to an irregular precipitation regime with prolonged dry periods.

  11. The effect of farmyard manure and calcium ammonium nitrate ...

    African Journals Online (AJOL)

    The effect of farmyard manure and calcium ammonium nitrate fertilisers on micronutrient density (iron, zinc, manganese, calcium and potassium) and seed yields of solanium villosum (black nightshade) and cleome gynandra (cat whiskers) on uetric nitisol.

  12. Stability and Concentration Verification of Ammonium Perchlorate Dosing Solutions

    National Research Council Canada - National Science Library

    Tsui, David

    1998-01-01

    Stability and concentration verification was performed for the ammonium perchlorate dosing solutions used in the on-going 90-Day Oral Toxicity Study conducted by Springborn Laboratories, Inc. (SLI Study No. 3433.1...

  13. Direct esterification of ammonium salts of carboxylic acids

    Science.gov (United States)

    Halpern, Yuval [Skokie, IL

    2003-06-24

    A non-catalytic process for producing esters, the process comprising reacting an ammonium salt of a carboxylic acid with an alcohol and removing ammonia from the reaction mixture. Selectivities for the desired ester product can exceed 95 percent.

  14. The effect of farmyard manure and calcium ammonium nitrate on ...

    African Journals Online (AJOL)

    The effect of farmyard manure and calcium ammonium nitrate on vegetative growth, leaf yield and nutritive quality of Cleome gynadra (Cat Whiskers) in Keiyo District, Rift Valley Province. MJ Hutchinson, LK Kipkosgei, E Obudho, LSM Akundabweni ...

  15. Quaternary ammonium salt N-(dodecyloxycarboxymethyl)- N,N,N ...

    Indian Academy of Sciences (India)

    2016-10-22

    N-(dodecyloxycarboxymethyl)-. N,N,N-trimethyl ammonium chloride) on yeast cells of the parental strain and the IM-resistant mutant (EO25 IMR) growth. The phenotype of this mutant was pleiotropic. The IMR mutant exhibited ...

  16. The thermal decomposition behavior of ammonium perchlorate and of an ammonium-perchlorate-based composite propellant

    Energy Technology Data Exchange (ETDEWEB)

    Behrens, R.; Minier, L.

    1998-03-24

    The thermal decomposition of ammonium perchlorate (AP) and ammonium-perchlorate-based composite propellants is studied using the simultaneous thermogravimetric modulated beam mass spectrometry (STMBMS) technique. The main objective of the present work is to evaluate whether the STMBMS can provide new data on these materials that will have sufficient detail on the reaction mechanisms and associated reaction kinetics to permit creation of a detailed model of the thermal decomposition process. Such a model is a necessary ingredient to engineering models of ignition and slow-cookoff for these AP-based composite propellants. Results show that the decomposition of pure AP is controlled by two processes. One occurs at lower temperatures (240 to 270 C), produces mainly H{sub 2}O, O{sub 2}, Cl{sub 2}, N{sub 2}O and HCl, and is shown to occur in the solid phase within the AP particles. 200{micro} diameter AP particles undergo 25% decomposition in the solid phase, whereas 20{micro} diameter AP particles undergo only 13% decomposition. The second process is dissociative sublimation of AP to NH{sub 3} + HClO{sub 4} followed by the decomposition of, and reaction between, these two products in the gas phase. The dissociative sublimation process occurs over the entire temperature range of AP decomposition, but only becomes dominant at temperatures above those for the solid-phase decomposition. AP-based composite propellants are used extensively in both small tactical rocket motors and large strategic rocket systems.

  17. Anaerobic ammonium oxidation by anammox bacteria in the Black Sea

    Science.gov (United States)

    Kuypers, Marcel M. M.; Sliekers, A. Olav; Lavik, Gaute; Schmid, Markus; Jørgensen, Bo Barker; Kuenen, J. Gijs; Sinninghe Damsté, Jaap S.; Strous, Marc; Jetten, Mike S. M.

    2003-04-01

    The availability of fixed inorganic nitrogen (nitrate, nitrite and ammonium) limits primary productivity in many oceanic regions. The conversion of nitrate to N2 by heterotrophic bacteria (denitrification) is believed to be the only important sink for fixed inorganic nitrogen in the ocean. Here we provide evidence for bacteria that anaerobically oxidize ammonium with nitrite to N2 in the world's largest anoxic basin, the Black Sea. Phylogenetic analysis of 16S ribosomal RNA gene sequences shows that these bacteria are related to members of the order Planctomycetales performing the anammox (anaerobic ammonium oxidation) process in ammonium-removing bioreactors. Nutrient profiles, fluorescently labelled RNA probes, 15N tracer experiments and the distribution of specific `ladderane' membrane lipids indicate that ammonium diffusing upwards from the anoxic deep water is consumed by anammox bacteria below the oxic zone. This is the first time that anammox bacteria have been identified and directly linked to the removal of fixed inorganic nitrogen in the environment. The widespread occurrence of ammonium consumption in suboxic marine settings indicates that anammox might be important in the oceanic nitrogen cycle.

  18. Mutagenicity of quaternary ammonium salts containing carbohydrate moieties

    Energy Technology Data Exchange (ETDEWEB)

    Dmochowska, Barbara [Department of Carbohydrate Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Piosik, Jacek; Woziwodzka, Anna [Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk (Poland); Sikora, Karol; Wisniewski, Andrzej [Department of Carbohydrate Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Wegrzyn, Grzegorz, E-mail: wegrzyn@biotech.univ.gda.pl [Department of Molecular Biology, University of Gdansk, Kladki 24, 80-822 Gdansk (Poland)

    2011-10-15

    Highlights: {yields} A series of quaternary ammonium salts containing carbohydrate moieties, with configuration D-galacto, D-gluco and D-manno, was synthesized and characterized. {yields} The quaternary ammonium salts containing carbohydrate moieties revealed potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. {yields} The N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. {yields} We suggest that quaternary ammonium salts may be more hazardous than previously supposed. - Abstract: Quaternary ammonium salts are widely used in industrial, agricultural, healthcare and domestic applications. They are believed to be safe compounds, with little or no health hazard to humans. However, in this report, we demonstrate that a series of newly synthesized quaternary ammonium salts containing carbohydrate moieties reveal potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. D-Gluco- and D-galacto-derivatives were found to have a higher mutagenic potential than D-manno-derivatives. Among the former groups of compounds, the N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. These results suggest that the safety of quaternary ammonium salts may be lower than previously supposed, indicating a need for testing such compounds for their mutagenicity.

  19. Synthesis and anticoagulant activity of the quaternary ammonium chitosan sulfates.

    Science.gov (United States)

    Fan, Lihong; Wu, Penghui; Zhang, Jinrong; Gao, Song; Wang, Libo; Li, Mingjia; Sha, Mingming; Xie, Weiguo; Nie, Min

    2012-01-01

    Quaternary ammonium chitosan sulfates with diverse degrees of substitution (DS) ascribed to sulfate groups between 0.52 and 1.55 were synthesized by reacting quaternary ammonium chitosan with an uncommon sulfating agent (N(SO(3)Na)(3)) that was prepared from sodium bisulfite (NaHSO(3)) through reaction with sodium nitrite (NaNO(2)) in the aqueous system homogeneous. The structures of the derivatives were characterized by FTIR, (1)H NMR and (13)C NMR. The factors affecting DS of quaternary ammonium chitosan sulfates which included the molar ratio of NaNO(2) to quaternary ammonium chitosan, sulfated temperature, sulfated time and pH of sulfated reaction solution were investigated in detail. Its anticoagulation activity in vitro was determined by an activated partial thromboplastin time (APTT) assay, a thrombin time (TT) assay and a prothrombin time (PT) assay. Results of anticoagulation assays showed quaternary ammonium chitosan sulfates significantly prolonged APTT and TT, but not PT, and demonstrated that the introduction of sulfate groups into the quaternary ammonium chitosan structure improved its anticoagulant activity obviously. The study showed its anticoagulant properties strongly depended on its DS, concentration and molecular weight. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

  20. Mutagenicity of quaternary ammonium salts containing carbohydrate moieties

    International Nuclear Information System (INIS)

    Dmochowska, Barbara; Piosik, Jacek; Woziwodzka, Anna; Sikora, Karol; Wisniewski, Andrzej; Wegrzyn, Grzegorz

    2011-01-01

    Highlights: → A series of quaternary ammonium salts containing carbohydrate moieties, with configuration D-galacto, D-gluco and D-manno, was synthesized and characterized. → The quaternary ammonium salts containing carbohydrate moieties revealed potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. → The N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. → We suggest that quaternary ammonium salts may be more hazardous than previously supposed. - Abstract: Quaternary ammonium salts are widely used in industrial, agricultural, healthcare and domestic applications. They are believed to be safe compounds, with little or no health hazard to humans. However, in this report, we demonstrate that a series of newly synthesized quaternary ammonium salts containing carbohydrate moieties reveal potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. D-Gluco- and D-galacto-derivatives were found to have a higher mutagenic potential than D-manno-derivatives. Among the former groups of compounds, the N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. These results suggest that the safety of quaternary ammonium salts may be lower than previously supposed, indicating a need for testing such compounds for their mutagenicity.

  1. Ammonium as sole N source improves grain quality in wheat.

    Science.gov (United States)

    Fuertes-Mendizábal, Teresa; González-Torralba, Jon; Arregui, Luis M; González-Murua, Carmen; González-Moro, M Begoña; Estavillo, José M

    2013-07-01

    The skilful handling of N fertilizer, including N source type and its timing, is necessary to obtain maximum profitability in wheat crops in terms of production and quality. Studies on grain yield and quality with ammonium as sole N source have not yet been conducted. The aim of this study was to evaluate the effect of N source management (nitrate vs. ammonium), and splitting it into two or three amendments during the wheat life cycle, on grain yield and quality under irrigated conditions. This experiment demonstrates that Cezanne wheat plants growing with ammonium as exclusive N source are able to achieve the same yield as plants growing with nitrate and that individual wheat plants grown in irrigated pots can efficiently use late N applied in GS37. Ammonium nutrition increased both types of grain reserve proteins (gliadins and glutenins) and also increased the ratio gli/glu with respect to nitrate nutrition. The splitting of the N rate enhanced the ammonium effect on grain protein composition. The application of ammonium N source, especially when split into three amendments, has an analogous effect on grain protein content and composition to applications at a higher N rate, leading to higher N use efficiency. © 2012 Society of Chemical Industry.

  2. 40 CFR 418.60 - Applicability; description of the ammonium sulfate production subcategory.

    Science.gov (United States)

    2010-07-01

    ... ammonium sulfate production subcategory. 418.60 Section 418.60 Protection of Environment ENVIRONMENTAL... CATEGORY Ammonium Sulfate Production Subcategory § 418.60 Applicability; description of the ammonium... production of ammonium sulfate by the synthetic process and by coke oven by-product recovery. The provisions...

  3. DISSOLUTION OF LANTHANUM FLUORIDE PRECIPITATES

    Science.gov (United States)

    Fries, B.A.

    1959-11-10

    A plutonium separatory ore concentration procedure involving the use of a fluoride type of carrier is presented. An improvement is given in the derivation step in the process for plutonium recovery by carrier precipitation of plutonium values from solution with a lanthanum fluoride carrier precipitate and subsequent derivation from the resulting plutonium bearing carrier precipitate of an aqueous acidic plutonium-containing solution. The carrier precipitate is contacted with a concentrated aqueous solution of potassium carbonate to effect dissolution therein of at least a part of the precipitate, including the plutonium values. Any remaining precipitate is separated from the resulting solution and dissolves in an aqueous solution containing at least 20% by weight of potassium carbonate. The reacting solutions are combined, and an alkali metal hydroxide added to a concentration of at least 2N to precipitate lanthanum hydroxide concomitantly carrying plutonium values.

  4. The Influence of Aerosol Hygroscopicity on Precipitation Intensity During a Mesoscale Convective Event

    Science.gov (United States)

    Kawecki, Stacey; Steiner, Allison L.

    2018-01-01

    We examine how aerosol composition affects precipitation intensity using the Weather and Research Forecasting Model with Chemistry (version 3.6). By changing the prescribed default hygroscopicity values to updated values from laboratory studies, we test model assumptions about individual component hygroscopicity values of ammonium, sulfate, nitrate, and organic species. We compare a baseline simulation (BASE, using default hygroscopicity values) with four sensitivity simulations (SULF, increasing the sulfate hygroscopicity; ORG, decreasing organic hygroscopicity; SWITCH, using a concentration-dependent hygroscopicity value for ammonium; and ALL, including all three changes) to understand the role of aerosol composition on precipitation during a mesoscale convective system (MCS). Overall, the hygroscopicity changes influence the spatial patterns of precipitation and the intensity. Focusing on the maximum precipitation in the model domain downwind of an urban area, we find that changing the individual component hygroscopicities leads to bulk hygroscopicity changes, especially in the ORG simulation. Reducing bulk hygroscopicity (e.g., ORG simulation) initially causes fewer activated drops, weakened updrafts in the midtroposphere, and increased precipitation from larger hydrometeors. Increasing bulk hygroscopicity (e.g., SULF simulation) simulates more numerous and smaller cloud drops and increases precipitation. In the ALL simulation, a stronger cold pool and downdrafts lead to precipitation suppression later in the MCS evolution. In this downwind region, the combined changes in hygroscopicity (ALL) reduces the overprediction of intense events (>70 mm d-1) and better captures the range of moderate intensity (30-60 mm d-1) events. The results of this single MCS analysis suggest that aerosol composition can play an important role in simulating high-intensity precipitation events.

  5. Effects of sodium ascorbate, sodium saccharin and ammonium chloride on the male rat urinary bladder.

    Science.gov (United States)

    Cohen, S M; Garland, E M; Cano, M; St John, M K; Khachab, M; Wehner, J M; Arnold, L L

    1995-11-01

    Sodium saccharin administered at high doses to male rats beginning after 5 weeks of age produces mild urothelial hyperplasia but does not result in a significant increase in incidence of bladder cancer unless it is administered after an initiating agent. However, if it is administered in a two-generation bioassay, a significant incidence of bladder tumors is produced. The hyperplastic and tumorigenic effects are inhibited by co-administration with high doses of NH4Cl. The present experiment was designed to evaluate the effects of another sodium salt, sodium ascorbate, administered through the neonatal time period. Sodium saccharin administered as 5% of the diet produced urothelial hyperplasia and increased labeling index, and this was inhibited by co-administration with 1.23% NH4Cl. Four doses of sodium ascorbate was evaluated. The lowest dose, 0.91%, was without effect on the urinary tract. A slight effect (not statistically significant) was observed at a dose of 2.73%, and a significant proliferative response was detected at 4.56 and 6.84%. Recent studies suggest that a calcium phosphate-containing amorphous precipitate forms in the urine of rats fed high doses of sodium saccharin, producing cytotoxicity of the urothelium and consequent regenerative hyperplasia. This precipitate was observed in the present experiment in the rats administered the high dose of sodium saccharin or the higher doses of sodium ascorbate. Formation of this precipitate and induction of urothelial proliferation were inhibited by co-administration of NH4Cl, but somewhat higher doses of ammonium chloride were required for doses of sodium ascorbate compared to sodium saccharin. These results demonstrate that sodium ascorbate administered through the neonatal time period of the male rat produces urothelial hyperplasia in the dose responsive manner, with a no-effect level of 0.91% of the diet. The formation of the calcium phosphate-containing amorphous precipitate and urothelial proliferation

  6. The Global Precipitation Climatology Project (GPCP) Combined Precipitation Dataset

    Science.gov (United States)

    Huffman, George J.; Adler, Robert F.; Arkin, Philip; Chang, Alfred; Ferraro, Ralph; Gruber, Arnold; Janowiak, John; McNab, Alan; Rudolf, Bruno; Schneider, Udo

    1997-01-01

    The Global Precipitation Climatology Project (GPCP) has released the GPCP Version 1 Combined Precipitation Data Set, a global, monthly precipitation dataset covering the period July 1987 through December 1995. The primary product in the dataset is a merged analysis incorporating precipitation estimates from low-orbit-satellite microwave data, geosynchronous-orbit -satellite infrared data, and rain gauge observations. The dataset also contains the individual input fields, a combination of the microwave and infrared satellite estimates, and error estimates for each field. The data are provided on 2.5 deg x 2.5 deg latitude-longitude global grids. Preliminary analyses show general agreement with prior studies of global precipitation and extends prior studies of El Nino-Southern Oscillation precipitation patterns. At the regional scale there are systematic differences with standard climatologies.

  7. Ammonium inhibition of nitrogenase activity in Herbaspirillum seropedicae

    Energy Technology Data Exchange (ETDEWEB)

    Fu, H.; Burris, R.H. (Univ. of Wisconsin, Madison (USA))

    1989-06-01

    The effect of oxygen, ammonium ion, and amino acids on nitrogenase activity in the root-associated N{sub 2}-fixing bacterium Herbaspirillum seropedicae was investigated in comparison with Azospirillum spp. and Rhodospirillum rubrum. H. seropedicae is microaerophilic, and its optimal dissolved oxygen level is from 0.04 to 0.2 kPa for dinitrogen fixation but higher when it is supplied with fixed nitrogen. No nitrogenase activity was detected when the dissolved O{sub 2} level corresponded to 4.0 kPa. Ammonium, a product of the nitrogenase reaction, reversible inhibited nitrogenase activity when added to derepressed cell cultures. However, the inhibition of nitrogenase activity was only partial even with concentrations of ammonium chloride as high as 20 mM. Amides such as glutamine and asparagine partially inhibited nitrogenase activity, but glutamate did not. Nitrogenase in crude extracts prepared from ammonium-inhibited cells showed activity as high as in extracts from N{sub 2}-fixing cells. The pattern of the dinitrogenase and the dinitrogenase reductase revealed by the immunoblotting technique did not change upon ammonium chloride treatment of cells in vivo. No homologous sequences were detected with the draT-draG probe from Azospirillum lipoferum. There is no clear evidence that ADP-ribosylation of the dinitrogenase reductase is involved in the ammonium inhibition of H. seropedicae. The uncoupler carbonyl cyanide m-chlorophenylhydrazone decreased the intracellular ATP concentration and inhibited the nitrogenase activity of whole cells. The ATP pool was significantly disturbed when cultures were treated with ammonium in vivo.

  8. Early metabolic effects and mechanism of ammonium transport in yeast

    International Nuclear Information System (INIS)

    Pena, A.; Pardo, J.P.; Ramirez, J.

    1987-01-01

    Studies were performed to define the effects and mechanism of NH+4 transport in yeast. The following results were obtained. Glucose was a better facilitator than ethanol-H 2 O 2 for ammonium transport; low concentrations of uncouplers or respiratory inhibitors could inhibit the transport with ethanol as the substrate. With glucose, respiratory inhibitors showed only small inhibitory effects, and only high concentrations of azide or trifluoromethoxy carbonylcyanide phenylhydrazone could inhibit ammonium transport. Ammonium in the free state could be concentrated approximately 200-fold by the cells. Also, the addition of ammonium produced stimulation of both respiration and fermentation; an increased rate of H+ extrusion and an alkalinization of the interior of the cell; a decrease of the membrane potential, as monitored by fluorescent cyanine; an immediate decrease of the levels of ATP and an increase of ADP, which may account for the stimulation of both fermentation and respiration; and an increase of the levels of inorganic phosphate. Ammonium was found to inhibit 86Rb+ transport much less than K+. Also, while K+ produced a competitive type of inhibition, that produced by NH4+ was of the noncompetitive type. From the distribution ratio of ammonium and the pH gradient, an electrochemical potential gradient of around -180 mV was calculated. The results indicate that ammonium is transported in yeast by a mechanism similar to that of monovalent alkaline cations, driven by a membrane potential. The immediate metabolic effects of this cation seem to be due to an increased [H+]ATPase, to which its transport is coupled. However, the carriers seem to be different. The transport system studied in this work was that of low affinity

  9. Ammonium Transformation in 14 Lakes along a Trophic Gradient

    Directory of Open Access Journals (Sweden)

    Barbara Leoni

    2018-03-01

    Full Text Available Ammonia is a widespread pollutant in aquatic ecosystems originating directly and indirectly from human activities, which can strongly affect the structure and functioning of the aquatic foodweb. The biological oxidation of NH4+ to nitrite, and then nitrate is a key part of the complex nitrogen cycle and a fundamental process in aquatic environments, having a profound influence on ecosystem stability and functionality. Environmental studies have shown that our current knowledge of physical and chemical factors that control this process and the abundance and function of involved microorganisms are not entirely understood. In this paper, the efficiency and the transformation velocity of ammonium into oxidised compounds in 14 south-alpine lakes in northern Italy, with a similar origin, but different trophic levels, are compared with lab-scale experimentations (20 °C, dark, oxygen saturation that are performed in artificial microcosms (4 L. The water samples were collected in different months to highlight the possible effect of seasonality on the development of the ammonium oxidation process. In four-liter microcosms, concentrations were increased by 1 mg/L NH4+ and the process of ammonium oxidation was constantly monitored. The time elapsed for the decrease of 25% and 95% of the initial ion ammonium concentration and the rate for that ammonium oxidation were evaluated. Principal Component Analysis and General Linear Model, performed on 56 observations and several chemical and physical parameters, highlighted the important roles of total phosphorus and nitrogen concentrations on the commencement of the oxidation process. Meanwhile, the natural concentration of ammonium influenced the rate of nitrification (µg NH4+/L day. Seasonality did not seem to significantly affect the ammonium transformation. The results highlight the different vulnerabilities of lakes with different trophic statuses.

  10. ISLSCP II Global Precipitation Climatology Centre (GPCC) Monthly Precipitation

    Data.gov (United States)

    National Aeronautics and Space Administration — The Global Precipitation Climatology Centre (GPCC), which is operated by the Deutscher Wetterdienst (National Meteorological Service of Germany), is a component of...

  11. Isotopes in Greenland Precipitation

    DEFF Research Database (Denmark)

    Faber, Anne-Katrine

    the Arctic Ocean. A comprehensive database is created based on ice core and weather station data from Greenland within the period 1890-2014. Present day annual and seasonal mean values are computed for 326 locations in Greenland. Parameterization of the spatial distribution of temperature and δ18O are used...... to create the first observational-based gridded map of δ18O of precipitation for Greenland and the first gridded map of Greenland temperature, where ice core borehole temperatures are included. The database and gridded maps create a framework for conducting model-data comparison of isotope-enabled GCMs......) Constructing a new Greenland database of observations and present-day ice core measurements, and (3) Performance test of isotope-enabled CAM5 for Greenland. The recent decades of rapid Arctic sea ice decline are used as a basis for an observational-based model experiment using the isotope-enabled CAM model 3...

  12. Progress in modeling asphaltene precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Yarranton, H.W.; Satyro, M.A. [Department of Chemical and Petroleum Engineering, University of Calgary (Canada); Taylor, S.D. [DBR Technology Center, Schlumberger (Canada)

    2011-07-01

    In the oil industry, asphaltene precipitation may happen when heavy oils are in contact with a solvent, crude oils are blended or when light oils containing asphaltenes are depressurized. Asphaltene precipitation has proven challenging to predict and the aim of this paper is to evaluate 2 different approaches for asphaltene precipitation modeling: regular solution and equation of state. Two case were studied: an Athabasca bitumen diluted with n-alkane and a depressurized Gulf of Mexico crude oil and both models were applied to each case. Results showed that both thermodynamic models are, to a limited extend, suitable for asphaltene precipitation prediction but they do not offer a correct prediction at low asphaltene concentrations and the equation of state cannot predict asphaltene precipitation from depressurized crude oils. This study showed the limits of current models in predicting precipitation of asphaltene and provided a trick to overcome these deficiencies; further work should be undertaken to develop a consistent approach.

  13. Origin of high ammonium, arsenic and boron concentrations in the proximity of a mine: Natural vs. anthropogenic processes

    Energy Technology Data Exchange (ETDEWEB)

    Scheiber, Laura, E-mail: scheiber.ls@gmail.com [Institute of Environmental Assessment and Water Research, CSIC, Jordi Girona 18. E-08034 Barcelona (Spain); Ayora, Carlos; Vázquez-Suñé, Enric [Institute of Environmental Assessment and Water Research, CSIC, Jordi Girona 18. E-08034 Barcelona (Spain); Cendón, Dioni I. [Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); School of Biological, Earth and Environmental Sciences (BEES), University of New South Wales (UNSW), NSW 2052 (Australia); Soler, Albert [Departament de Cristallografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona, C/Martí Franquès, sn., Barcelona (Spain); Baquero, Juan Carlos [Cobre Las Cruces S.A., Carretera SE-3410 km 4, 41860 Gerena, Sevilla (Spain)

    2016-01-15

    High ammonium (NH{sub 4}), arsenic (As) and boron (B) concentrations are found in aquifers worldwide and are often related to human activities. However, natural processes can also lead to groundwater quality problems. High NH{sub 4}, As and B concentrations have been identified in the confined, deep portion of the Niebla-Posadas aquifer, which is near the Cobre Las Cruces (CLC) mining complex. The mine has implemented a Drainage and Reinjection System comprising two rings of wells around the open pit mine, were the internal ring drains and the external ring is used for water reinjection into the aquifer. Differentiating geogenic and anthropogenic sources and processes is therefore crucial to ensuring good management of groundwater in this sensitive area where groundwater is extensively used for agriculture, industry, mining and human supply. No NH{sub 4}, As and B are found in the recharge area, but their concentrations increase with depth, salinity and residence time of water in the aquifer. The increased salinity down-flow is interpreted as the result of natural mixing between infiltrated meteoric water and the remains of connate waters (up to 8%) trapped within the pores. Ammonium and boron are interpreted as the result of marine solid organic matter degradation by the sulfate dissolved in the recharge water. The light δ{sup 15}N{sub NH4} values confirm that its origin is linked to marine organic matter. High arsenic concentrations in groundwater are interpreted as being derived from reductive dissolution of As-bearing goethite by dissolved organic matter. The lack of correlation between dissolved Fe and As is explained by the massive precipitation of siderite, which is abundantly found in the mineralization. Therefore, the presence of high arsenic, ammonium and boron concentrations is attributed to natural processes. Ammonium, arsenic, boron and salinity define three zones of groundwater quality: the first zone is close to the recharge area and contains water

  14. Reuse of ammonium fluoride generated in the uranium hexafluoride conversion

    International Nuclear Information System (INIS)

    Silva Neto, J.B.; Carvalho, E.F. Urano de; Durazzo, M.; Riella, H.G

    2010-01-01

    The Nuclear Fuel Centre of IPEN / CNEN - SP develops and manufactures dispersion fuel with high uranium concentration to meet the demand of the IEA-R1 reactor and future research reactors planned to be constructed in Brazil. The fuel uses uranium silicide (U 3 Si 2 ) dispersed in aluminum. For producing the fuel, the processes for uranium hexafluoride (UF 6 ) conversion consist in obtaining U 3 Si 2 and / or U 3 O 8 through the preparation of intermediate compounds, among them ammonium uranyl carbonate - AUC, ammonium diuranate - DUA and uranium tetrafluoride - UF 4 . This work describes a procedure for preparing uranium tetrafluoride by a dry route using as raw material the filtrate generated when producing routinely ammonium uranyl carbonate. The filtrate consists primarily of a solution containing high concentrations of ammonium (NH 4 + ), fluoride (F - ), carbonate (CO 3 -- ) and low concentrations of uranium. The procedure is basically the recovery of NH 4 F and uranium, as UF 4 , through the crystallization of ammonium bifluoride (NH 4 HF 2 ) and, in a later step, the addition of UO 2 , occurring fluoridation and decomposition. The UF 4 obtained is further diluted in the UF 4 produced routinely at IPEN / CNEN-SP by a wet route process. (author)

  15. Radionuclide flow during the conversion of phosphogypsum to ammonium sulfate

    International Nuclear Information System (INIS)

    Burnett, W.C.; Schultz, M.K.; Hull, C.D.

    1996-01-01

    Approximately 30 million tons of the by-product phosphogypsum are currently produced annually by the phosphate fertilizer industry in Florida. Nearly all of this material is stockpiled because radioactive impurities prevent utilization of what could otherwise be a useful agricultural amendment or construction material. Long-term storage and maintenance of this material presents economic as well as potential environmental concerns. One partial solution to this problem may be conversion of phosphogypsum to ammonium sulfate by the so-called Merseberg ammonocarbonation process. Ammonium sulfate is an excellent fertilizer which supplies sulfur as well as nitrogen to soils. We have assessed the flow of the natural decay-series radionuclides 238 U, 226 Ra, 210 Pb and 210 Po through the Merseberg process by the analysis of starting materials and products from overseas industrial-scale plants. Results indicate that the radionuclides associated with phosphogypsum do not report to the ammonium sulfate product but are found instead almost exclusively in the by-product calcium carbonate. Thus, the radiochemical results are encouraging in terms of using this process as an option for partial removal of waste phosphogypsum. Although there is a clear and recognized need for increased sulfur addition to many crops, the price of sulfur has been so low and alternative supplies of ammonium so common that investment in this process has been discouraged. Recent price increases and demand for ammonium sulfate may make the Merseberg process more attractive. (author)

  16. Electrical operation of electrostatic precipitators

    CERN Document Server

    Parker, Ken

    2003-01-01

    The electrostatic precipitator remains on of the most cost effective means of controlling the emission of particulates from most industrial processes. This book will be of interest to both users and suppliers of electrostatic precipitators as well as advanced students on environmental based courses. The author identifies the physical and engineering basis for the development of electrical equipment for electrostatic precipitators and thoroughly explores the technological factors which optimize the efficiency of the precipitator and hence minimize emissions, as well as future developments in th

  17. Measuring precipitation with a geolysimeter

    Science.gov (United States)

    Smith, Craig D.; van der Kamp, Garth; Arnold, Lauren; Schmidt, Randy

    2017-10-01

    Using the relationship between measured groundwater pressures in deep observation wells and total surface loading, a geological weighing lysimeter (geolysimeter) has the capability of measuring precipitation event totals independently of conventional precipitation gauge observations. Correlations between groundwater pressure change and event precipitation were observed at a co-located site near Duck Lake, SK, over a multi-year and multi-season period. Correlation coefficients (r2) varied from 0.99 for rainfall to 0.94 for snowfall. The geolysimeter was shown to underestimate rainfall by 7 % while overestimating snowfall by 9 % as compared to the unadjusted gauge precipitation. It is speculated that the underestimation of rainfall is due to unmeasured run-off and evapotranspiration within the response area of the geolysimeter during larger rainfall events, while the overestimation of snow is at least partially due to the systematic undercatch common to most precipitation gauges due to wind. Using recently developed transfer functions from the World Meteorological Organization's (WMO) Solid Precipitation Intercomparison Experiment (SPICE), bias adjustments were applied to the Alter-shielded, Geonor T-200B precipitation gauge measurements of snowfall to mitigate wind-induced errors. The bias between the gauge and geolysimeter measurements was reduced to 3 %. This suggests that the geolysimeter is capable of accurately measuring solid precipitation and can be used as an independent and representative reference of true precipitation.

  18. Precipitation Measurement Missions Data Access

    Data.gov (United States)

    National Aeronautics and Space Administration — Tropical Rainfall Measuring Mission (TRMM) data products are currently available from 1998 to the present. Global Precipitation Measurement (GPM) mission data...

  19. Study on mechanism of isomerization between ammonium thiocyanate and thiourea

    Science.gov (United States)

    Zhang, Chao-Zhi; Niu, Meng-Xiao

    2016-12-01

    Application of ammonium thiocyanate that can be separated from wastewater in coking plant is limited. It may isomerize to thiourea which has widely applied in industry. However, the isomerization yield is low. Moreover, the isomerization temperature is more than 145 °C. In this paper, the isomerization was investigated. The mechanism of the isomerization was supposed based on quantum chemistry calculations. Ammonia was employed as a catalyst to lower isomerization temperature and improved the yield of thiourea in the isomerization reaction. Results of quantum chemical calculation and experiments support the supposed mechanism. The mechanism can be applied in production of thiourea from isomerization of ammonium thiocyanate. The paper suggests a useful way of resourcizing ammonium thiocyanate in wastewater.

  20. Temperature rising characteristics of ammonium diurante in microwave fields

    International Nuclear Information System (INIS)

    Liu Bingguo; Peng JinHui; Huang Daifu; Zhang Libo; Hu Jinming; Zhuang Zebiao; Kong Dongcheng; Guo Shenghui; Li Chunxiang

    2010-01-01

    The temperature rising characteristics of ammonium diurante, triuranium octaoxide (U 3 O 8 ), and their mixture were investigated under microwave irradiation, aiming at exploring newly theoretical foundation for advanced metallurgical methods. The temperature rising curves showed that ammonium diurante had weak capability to absorb microwave energy, while triuranium octaoxide had the very strong absorption capability. The temperature of mixture containing 20% of U 3 O 8 could rise from room temperature to 1171 K within 280 s. The ability to absorb microwave energy for the mixture with different ratios increased with the increase in the amount of U 3 O 8 . These are in good agreement with the results of Maxwell-Garnett effective medium theory. It is feasible to calcine ammonium diurante by adding of small amounts of U 3 O 8 in microwave fields.

  1. Rocket Solid Propellant Alternative Based on Ammonium Dinitramide

    Directory of Open Access Journals (Sweden)

    Grigore CICAN

    2017-03-01

    Full Text Available Due to the continuous run for a green environment the current article proposes a new type of solid propellant based on the fairly new synthesized oxidizer, ammonium dinitramide (ADN. Apart of having a higher specific impulse than the worldwide renowned oxidizer, ammonium perchlorate, ADN has the advantage, of leaving behind only nitrogen, oxygen and water after decomposing at high temperatures and therefore totally avoiding the formation of hydrogen chloride fumes. Based on the oxidizer to fuel ratios of the current formulations of the major rocket solid booster (e.g. Space Shuttle’s SRB, Ariane 5’s SRB which comprises mass variations of ammonium perchlorate oxidizer (70-75%, atomized aluminum powder (10-18% and polybutadiene binder (12-20% a new solid propellant was formulated. As previously stated, the new propellant formula and its variations use ADN as oxidizer and erythritol tetranitrate as fuel, keeping the same polybutadiene as binder.

  2. CEOS precipitation constellation

    Science.gov (United States)

    Neeck, Steven P.; Oki, Riko

    2007-10-01

    The outcomes of the 19th Committee on Earth Observing Satellites (CEOS) Plenary held in London in November 2005, recognized that the CEOS Implementation Plan for Space-Based Observations for Global Earth Observation System of Systems (GEOSS) should: - identify the supply of space-based observations required to satisfy the requirements expressed by the 10-year implementation plan for GEOSS; and - propose an innovative process whereby the many disparate types of Earth observing programs funded by CEOS Member agencies might contribute to the supply of the required observations. The CEOS Task Force charged with drafting the CEOS Implementation Plan for Space-Based Observations for GEOSS focused its early efforts on the creation of a 'new planning process' which would satisfy the various criteria demanded by member space agencies, and which would hopefully encourage a new phase of specificity and focus in the multi-lateral co-operation efforts undertaken by space agencies under the CEOS umbrella - resulting in improved engagement of all CEOS Members and real implementation results. The CEOS Constellations is the title given to this new process, and four pilot studies have been initiated in order to pioneer and test the concept. The Japan Aerospace Exploration Agency (JAXA) and the National Aeronautics and Space Administration (NASA) were selected as the lead agencies for the study of the development of a CEOS Precipitation Constellation with the support of other CEOS space agency and user community participants. The goals, approach, and anticipated outcomes for the study will be discussed.

  3. Precipitation in the Solar System

    Science.gov (United States)

    McIntosh, Gordon

    2007-01-01

    As an astronomy instructor, I am always looking for commonly observed Earthly experiences to help my students and me understand and appreciate similar occurrences elsewhere in the solar system. Recently I wrote a short TPT article on frost. This paper is on the related phenomena of precipitation. Precipitation, so common on most of the Earth's…

  4. Method of precipitating uranium peroxide

    International Nuclear Information System (INIS)

    Hardwick, T.J.

    1986-01-01

    The uranium dissolved as uranyl tricarbonate ion in an aqueous alkaline solution is precipitated out as uranium peroxide. The precipitation is carried out by acidifying a portion of the aqueous alkaline solution with excess sulfuric acid to convert the uranyl tricarbonate ion to the uranyl ion and carbon dioxide. This is followed by the addition of hydrogen peroxide to the acidified solution to convert the uranyl ion to uranium peroxide precipitate, producing additional acid. Concurrently, a different portion of the aqueous alkaline uranyl tricarbonate solution is added to the precipitating solution to elevate the pH to an acidic range which is optimum for effective reaction to uranium peroxide and for its precipitation

  5. Encoding information into precipitation structures

    International Nuclear Information System (INIS)

    Martens, Kirsten; Bena, Ioana; Droz, Michel; Rácz, Zoltan

    2008-01-01

    Material design at submicron scales would be profoundly affected if the formation of precipitation patterns could be easily controlled. It would allow the direct building of bulk structures, in contrast to traditional techniques which consist of removing material in order to create patterns. Here, we discuss an extension of our recent proposal of using electrical currents to control precipitation bands which emerge in the wake of reaction fronts in A + + B – → C reaction–diffusion processes. Our main result, based on simulating the reaction–diffusion–precipitation equations, is that the dynamics of the charged agents can be guided by an appropriately designed time-dependent electric current so that, in addition to the control of the band spacing, the width of the precipitation bands can also be tuned. This makes straightforward the encoding of information into precipitation patterns and, as an amusing example, we demonstrate the feasibility by showing how to encode a musical rhythm

  6. Ammonium transformation in a nitrogen-rich tidal freshwater marsh

    DEFF Research Database (Denmark)

    Gribsholt, B.; Andersson, M.; Boschker, H.T.S.

    2006-01-01

    The fate and transport of watershed-derived ammonium in a tidal freshwater marsh fringing the nutrient rich Scheldt River, Belgium, was quantified in a whole ecosystem 15N labeling experiment. In late summer (September) we added 15N-NH4+ to the flood water entering a 3477 m2 tidal freshwater marsh...

  7. Anaerobic ammonium oxidation by Anammox bacteria in the Black Sea

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Kuypers, M.M.M.; Sliekers, O.; Lavik, G.; Schmid, M.; Jørgensen, B.B.; Kuenen, J.G.; Strous, M.; Jetten, M.S.M.

    2003-01-01

    The availability of fixed inorganic nitrogen (nitrate, nitrite and ammonium) limits primary productivity in many oceanic regions1. The conversion of nitrate to N2 by heterotrophic bacteria (denitrification) is believed to be the only important sink for fixed inorganic nitrogen in the ocean2. Here we

  8. Inorganic–Organic Hybrids Incorporating a Chiral Cyclic Ammonium ...

    African Journals Online (AJOL)

    organic hybrids containing various lead halides as the inorganic motif and a chiral, primary ammonium cation as the organic constituent. The organic cation investigated is (C6H11C*H(CH3)NH3)+ and both the (R) and (S) as well as the racemic ...

  9. Structural characterization of ammonium uranate by infrared spectroscopy

    International Nuclear Information System (INIS)

    Rodriguez S, A.

    1994-01-01

    Infrared spectroscopy have been used to investigate the chemical composition of some ammonium uranates. In this study, I have attempted to establish the interrelationship between the structure of the products, the character of their infrared spectra and x-ray diffraction data capable of consistent interpretation in terms of defining the compounds. (Author)

  10. Increase of water resistance of ammonium nitrate explosives

    Directory of Open Access Journals (Sweden)

    Zulkhair Mansurov

    2012-03-01

    Full Text Available Developed a method of kapsulating of ammonium nitrate with liquid paraffin increase finding explosives in water for 60 minutes. Placing explosives in the plastic shell, the explosive was, as in standing or running water during the day. When conducting field tests failures were absent.

  11. Cell biology of anaerobic ammonium-oxidizing bacteria

    NARCIS (Netherlands)

    Niftrik, L.A.M.P. van

    2008-01-01

    Anammox bacteria perform anaerobic ammonium oxidation to dinitrogen gas and belong to the phylum Planctomycetes. Whereas most Prokaryotes consist of one compartment, the cytoplasm bounded by the cytoplasmic membrane and cell wall, the species within this phylum are compartmentalized by intracellular

  12. Ammonia loss, ammonium and nitrate accumulation from mixing ...

    African Journals Online (AJOL)

    user

    2011-04-25

    Apr 25, 2011 ... Ammonia loss from urea significantly hinders efficient use of urea in agriculture. In order to reduce ammonia loss and, at the same time, improve beneficial accumulation of soil exchangeable ammonium and nitrate for efficient utilization by plants, this laboratory study was conducted to determine the effect.

  13. Ammonia loss, ammonium and nitrate accumulation from mixing ...

    African Journals Online (AJOL)

    Ammonia loss from urea significantly hinders efficient use of urea in agriculture. In order to reduce ammonia loss and, at the same time, improve beneficial accumulation of soil exchangeable ammonium and nitrate for efficient utilization by plants, this laboratory study was conducted to determine the effect of mixing urea with ...

  14. 21 CFR 172.430 - Iron ammonium citrate.

    Science.gov (United States)

    2010-04-01

    ... HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION... citrate. (b) The additive is used, or intended for use as an anticaking agent in salt for human consumption so that the level of iron ammonium citrate does not exceed 25 parts per million (0.0025 percent...

  15. Producing ammonium sulfate from flue gas desulfurization by-products

    Science.gov (United States)

    Chou, I.-Ming; Bruinius, J.A.; Benig, V.; Chou, S.-F.J.; Carty, R.H.

    2005-01-01

    Emission control technologies using flue gas desulfurization (FGD) have been widely adopted by utilities burning high-sulfur fuels. However, these technologies require additional equipment, greater operating expenses, and increased costs for landfill disposal of the solid by-products produced. The financial burdens would be reduced if successful high-volume commercial applications of the FGD solid by-products were developed. In this study, the technical feasibility of producing ammonium sulfate from FGD residues by allowing it to react with ammonium carbonate in an aqueous solution was preliminarily assessed. Reaction temperatures of 60, 70, and 80??C and residence times of 4 and 6 hours were tested to determine the optimal conversion condition and final product evaluations. High yields (up to 83%) of ammonium sulfate with up to 99% purity were achieved under relatively mild conditions. The optimal conversion condition was observed at 60??C and a 4-hour residence time. The results of this study indicate the technical feasibility of producing ammonium sulfate fertilizer from an FGD by-product. Copyright ?? Taylor & Francis Inc.

  16. Nitrate, Nitrite, and Ammonium Variability in Drinking Water Distribution Systems.

    Science.gov (United States)

    Schullehner, Jörg; Stayner, Leslie; Hansen, Birgitte

    2017-03-09

    Accurate assessments of exposure to nitrate in drinking water is a crucial part of epidemiological studies investigating long-term adverse human health effects. However, since drinking water nitrate measurements are usually collected for regulatory purposes, assumptions on (1) the intra-distribution system variability and (2) short-term (seasonal) concentration variability have to be made. We assess concentration variability in the distribution system of nitrate, nitrite, and ammonium, and seasonal variability in all Danish public waterworks from 2007 to 2016. Nitrate concentrations at the exit of the waterworks are highly correlated with nitrate concentrations within the distribution net or at the consumers' taps, while nitrite and ammonium concentrations are generally lower within the net compared with the exit of the waterworks due to nitrification. However, nitrification of nitrite and ammonium in the distribution systems only results in a relatively small increase in nitrate concentrations. No seasonal variation for nitrate, nitrite, or ammonium was observed. We conclude that nitrate measurements taken at the exit of the waterworks are suitable to calculate exposures for all consumers connected to that waterworks and that sampling frequencies in the national monitoring programme are sufficient to describe temporal variations in longitudinal studies.

  17. Growth features of ammonium hydrogen d-tartrate single crystals

    Indian Academy of Sciences (India)

    Unknown

    Ammonium hydrogen d-tartrate (d-AHT) single crystals were grown in silica gel. The growth fea- tures of these crystals with variation of parameters like specific gravity of the gel, gel pH, acid concentrations, concentration of the feed solution and gel age were studied in detail. Keywords. d-AHT single crystals; growth features ...

  18. Response of higveld grass species to ammonium and nitrate nitrogen

    African Journals Online (AJOL)

    Forty-one populations in twenty-two species of highveld grasses were grown in pots of soil fertilized with solutions for comparing ammonium and nitrate nutrition. Cotton, tomato, cereal crops and pasture grasses were included for comparison. Roots and shoots were harvested separately, weighed and analysed for major ...

  19. Nitrate and ammonium levels of some water bodies and their ...

    African Journals Online (AJOL)

    The present study examined the nitrate (NO3-) and ammonium (NH4+) levels of Rivers Wouri and Dibamba and some streams that feed them. The interaction of NO3- and NH4+ with some soil properties was also investigated. It was necessitated by the usage of these rivers for livelihood, despite the deposition of discharges ...

  20. Quaternary ammonium salt N-(dodecyloxycarboxymethyl)- N,N,N ...

    Indian Academy of Sciences (India)

    2016-10-22

    Oct 22, 2016 ... viruses like HIV (human immunodeficiency virus) and HBV. (hepatitis B virus), but not nonenveloped viruses ( ..... To investigate whether quaternary ammonium salt IM impacts yeast growth in the presence of ... To investigate the influence of IM on plasma membrane lipid composition, the ergosterol and fatty ...

  1. Acid mine water neutralisation with ammonium hydroxide and ...

    African Journals Online (AJOL)

    This study showed that NH4OH can be used for treatment of acid mine drainage rich in sulphates and NH4OH can be recycled in the process. Hydrated lime treatment resulted in removal of the remaining ammonia using a rotary evaporator. Keywords: acid mine water, ammonium hydroxide, barium hydroxide, sulphate ...

  2. Ceric ammonium nitrate catalysed three component one-pot efficient ...

    Indian Academy of Sciences (India)

    Wintec

    For this reason, the development of mild, efficient and versatile method is still important. Ceric (IV) ammonium nitrate (CAN) is a conven- ient and widely used reagent for affecting a wide ar- ray of synthetic transformations due to its many advantages such as solubility in organic solvents, low toxicity, high reactivity, and ease ...

  3. Ammonium derivatives of chromenones and quinolinones as lead ...

    Indian Academy of Sciences (India)

    A series of novel ammonium derivatives were synthesized and examined for their antimicrobial efficacy. Comparison of antimicrobial spectrum revealed that compounds 9, 11, 16 and 23 had strong potential against pathogens in vitro. Cytotoxicity results showed compound 9 to be least toxic, it is non-toxic to A549 and U87 ...

  4. Effect of Ammonium Nitrate Solutions on Fertilization and ...

    African Journals Online (AJOL)

    ... 10 and 100 p.p.m. ammonium nitrate and the percentage fertilization as weD as the subsequent development of the embryos compared with controls. At 10 and 100 p.p.m. there is a marked reduction in fertilization. Abnormal forms are common at 100 p.p.m. and some 95 % of the population fail to reach the gastrula stage.

  5. Electrochemical oxidation of quaternary ammonium electrolytes : Unexpected side reactions in organic electrochemistry

    NARCIS (Netherlands)

    Nouri Nigjeh, Eslam; de Vries, Marcel; Bruins, Andries P.; Bischoff, Rainer; Permentier, Hjalmar P.

    Quaternary ammonium salts are among the most widely used electrolytes in organic electrochemistry, but there is little known about their unwanted side oxidation reactions. We have, therefore, studied the constant potential oxidation products of quaternary ammonium electrolytes using mass

  6. Precipitation Measurements from Space: The Global Precipitation Measurement Mission

    Science.gov (United States)

    Hou, Arthur Y.

    2007-01-01

    Water is fundamental to the life on Earth and its phase transition between the gaseous, liquid, and solid states dominates the behavior of the weather/climate/ecological system. Precipitation, which converts atmospheric water vapor into rain and snow, is central to the global water cycle. It regulates the global energy balance through interactions with clouds and water vapor (the primary greenhouse gas), and also shapes global winds and dynamic transport through latent heat release. Surface precipitation affects soil moisture, ocean salinity, and land hydrology, thus linking fast atmospheric processes to the slower components of the climate system. Precipitation is also the primary source of freshwater in the world, which is facing an emerging freshwater crisis in many regions. Accurate and timely knowledge of global precipitation is essential for understanding the behavior of the global water cycle, improving freshwater management, and advancing predictive capabilities of high-impact weather events such as hurricanes, floods, droughts, and landslides. With limited rainfall networks on land and the impracticality of making extensive rainfall measurements over oceans, a comprehensive description of the space and time variability of global precipitation can only be achieved from the vantage point of space. This presentation will examine current capabilities in space-borne rainfall measurements, highlight scientific and practical benefits derived from these observations to date, and provide an overview of the multi-national Global Precipitation Measurement (GPM) Mission scheduled to bc launched in the early next decade.

  7. On the Precipitation and Precipitation Change in Alaska

    Directory of Open Access Journals (Sweden)

    Gerd Wendler

    2017-12-01

    Full Text Available Alaska observes very large differences in precipitation throughout the state; southeast Alaska experiences consistently wet conditions, while northern Arctic Alaska observes very dry conditions. The maximum mean annual precipitation of 5727 mm is observed in the southeastern panhandle at Little Port Arthur, while the minimum of 92 mm occurs on the North Slope at Kuparuk. Besides explaining these large differences due to geographic and orographic location, we discuss the changes in precipitation with time. Analyzing the 18 first-order National Weather Service stations, we found that the total average precipitation in the state increased by 17% over the last 67 years. The observed changes in precipitation are furthermore discussed as a function of the observed temperature increase of 2.1 °C, the mean temperature change of the 18 stations over the same period. This observed warming of Alaska is about three times the magnitude of the mean global warming and allows the air to hold more water vapor. Furthermore, we discuss the effect of the Pacific Decadal Oscillation (PDO, which has a strong influence on both the temperature and precipitation in Alaska.

  8. Investigation of electric discharge treatment of water for ammonium nitrogen removal

    International Nuclear Information System (INIS)

    Nazarenko, O.B.; Shubin, B.G.

    2007-01-01

    The possibility of water purification from ammonium nitrogen using pulsed electric discharge in water-air mixtures was investigated. The model solution of chlorous ammonium was used in experiments. The concentration of ions ammonium was about 300 mg/l. Achieved reduction of ammonium concentration was about 35%. In this paper the mechanism of this process is discussed. The ways to increasing efficiency of this method are proposed

  9. Optimization of ammonium sulfate concentration for purification of colorectal cancer vaccine candidate recombinant protein GA733-FcK isolated from plants

    Directory of Open Access Journals (Sweden)

    Se-Ra ePark

    2015-11-01

    Full Text Available A protein purification procedure is required to obtain high-value recombinant injectable vaccine proteins produced in plants as a bioreactor. However, existing purification procedures for plant-derived recombinant proteins are often not optimized and are inefficient, with low recovery rates. In our previous study, we used 25-30% ammonium sulfate to precipitate total soluble proteins (TSPs in purification process for recombinant proteins from plant leaf biomass which has not been optimized. Thus, the objective in this study is to optimize the conditions for plant-derived protein purification procedures. Various ammonium sulfate concentrations (15-80% were compared to determine their effects on TSPs yield. With 50% ammonium sulfate, the yield of precipitated TSP was the highest, and that of the plant-derived colorectal cancer-specific surface glycoprotein GA733 fused to the Fc fragment of human IgG tagged with endoplasmic reticulum (ER retention signal KDEL (GA733P-FcK protein significantly increased 1.8-fold. SDS-PAGE analysis showed that the purity of GA733P-FcK protein band appeared to be similar to that of an equal dose of mammalian-derived GA733-Fc (GA733M-Fc. The binding activity of purified GA733P-FcK to anti-GA733 mAb was as efficient as the native GA733M-Fc. Thus, the purification process was effectively optimized for obtaining a high yield of plant-derived antigenic protein with good quality. In conclusion, the purification recovery rate of large quantities of recombinant protein from plant expression systems can be enhanced via optimization of ammonium sulfate concentration during downstream processes, thereby offering a promising solution for production of recombinant GA733-Fc protein in plants.

  10. Optimization of Ammonium Sulfate Concentration for Purification of Colorectal Cancer Vaccine Candidate Recombinant Protein GA733-FcK Isolated from Plants.

    Science.gov (United States)

    Park, Se-Ra; Lim, Chae-Yeon; Kim, Deuk-Su; Ko, Kisung

    2015-01-01

    A protein purification procedure is required to obtain high-value recombinant injectable vaccine proteins produced in plants as a bioreactor. However, existing purification procedures for plant-derived recombinant proteins are often not optimized and are inefficient, with low recovery rates. In our previous study, we used 25-30% ammonium sulfate to precipitate total soluble proteins (TSPs) in purification process for recombinant proteins from plant leaf biomass which has not been optimized. Thus, the objective in this study is to optimize the conditions for plant-derived protein purification procedures. Various ammonium sulfate concentrations (15-80%) were compared to determine their effects on TSPs yield. With 50% ammonium sulfate, the yield of precipitated TSP was the highest, and that of the plant-derived colorectal cancer-specific surface glycoprotein GA733 fused to the Fc fragment of human IgG tagged with endoplasmic reticulum retention signal KDEL (GA733(P)-FcK) protein significantly increased 1.8-fold. SDS-PAGE analysis showed that the purity of GA733(P)-FcK protein band appeared to be similar to that of an equal dose of mammalian-derived GA733-Fc (GA733(M)-Fc). The binding activity of purified GA733(P)-FcK to anti-GA733 mAb was as efficient as the native GA733(M)-Fc. Thus, the purification process was effectively optimized for obtaining a high yield of plant-derived antigenic protein with good quality. In conclusion, the purification recovery rate of large quantities of recombinant protein from plant expression systems can be enhanced via optimization of ammonium sulfate concentration during downstream processes, thereby offering a promising solution for production of recombinant GA733-Fc protein in plants.

  11. The precipitation of vanadium compounds

    International Nuclear Information System (INIS)

    Martins, A.H.; Cassa, J.C.S.

    1987-01-01

    The results of a study on the chemistry of the precipitation process of vanadium compounds in sulfuric media are presented, in order to recover the vanadium contained in the ore from Campo Alegre de Lourdes (Bahia-Brazil). (Author) [pt

  12. Identifying Anomality in Precipitation Processes

    Science.gov (United States)

    Jiang, P.; Zhang, Y.

    2014-12-01

    Safety, risk and economic analyses of engineering constructions such as storm sewer, street and urban drainage, and channel design are sensitive to precipitation storm properties. Whether the precipitation storm properties exhibit normal or anomalous characteristics remains obscure. In this study, we will decompose a precipitation time series as sequences of average storm intensity, storm duration and interstorm period to examine whether these sequences could be treated as a realization of a continuous time random walk with both "waiting times" (interstorm period) and "jump sizes" (average storm intensity and storm duration). Starting from this viewpoint, we will analyze the statistics of storm duration, interstorm period, and average storm intensity in four regions in southwestern United States. We will examine whether the probability distribution is temporal and spatial dependent. Finally, we will use fractional engine to capture the randomness in precipitation storms.

  13. Environmental Radioactivity, Temperature, and Precipitation.

    Science.gov (United States)

    Riland, Carson A.

    1996-01-01

    Reports that environmental radioactivity levels vary with temperature and precipitation and these effects are due to radon. Discusses the measurement of this environmental radioactivity and the theory behind it. (JRH)

  14. Hourly and Daily Precipitation Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Precipitation reports submitted on many form types, including tabular and autographic charts. Reports are almost exclusively from the US Cooperative Observer Network.

  15. 40 CFR 418.40 - Applicability; description of the ammonium nitrate subcategory.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true Applicability; description of the ammonium nitrate subcategory. 418.40 Section 418.40 Protection of Environment ENVIRONMENTAL PROTECTION... Ammonium Nitrate Subcategory § 418.40 Applicability; description of the ammonium nitrate subcategory. The...

  16. 40 CFR 721.10170 - Polyoxyethylene polyalkylarylphenylether sulfate ammonium salt (generic).

    Science.gov (United States)

    2010-07-01

    ... polyalkylarylphenylether sulfate ammonium salt (generic). 721.10170 Section 721.10170 Protection of Environment... polyalkylarylphenylether sulfate ammonium salt (generic). (a) Chemical substance and significant new uses subject to... sulfate ammonium salt (PMN P-03-197) is subject to reporting under this section for the significant new...

  17. Influence of Ammonium Salt and Fermentation pH on Acarbose ...

    African Journals Online (AJOL)

    Purpose: To investigate the effect of ammonium salts and fermentation pH on the biosynthesis of acarbose by Streptomyces M37. Methods: Different ammonium salts were added to the fermentation broth of Streptomyces M37 to explore their effects on acarbose production. The concentration and addition time of ammonium ...

  18. Statistical analysis of precipitation chemistry measurements over the eastern United States. IV - The influences of meteorological factors

    Science.gov (United States)

    Maxwell, C.; Eynon, Barrett P.; Endlich, Roy M.

    1988-12-01

    The effects of several meteorological factors on the acidity and the concentration of the principal chemical ions in precipitation were investigated statistically using data from six sites selected from a new archive of daily precipitation chemistry measurements over the eastern United States between 1979 and 1983. At all sites, the highest concentrations of acidity, sulfate, and ammonium were found in rain, as compared with snow/ice or rain-snow/ice mixtures. In snow and ice, the concentrations of nitrate were found to be relatively high, while sulfate concentrations were very low. The presence or absence of thunder associated with precipitation had no detectable effect. Concentrations of all ions were found to decrease slightly as a function of precipitation amount per day.

  19. Sources et marché du sulfate d'ammonium Sources of and Market for Ammonium Sulfate

    Directory of Open Access Journals (Sweden)

    Loussouarn C.

    2006-11-01

    Full Text Available Engrais azoté le plus utilisé dans le monde jusqu'en 1970, le sulfate d'ammonium ne représente plus aujourd'hui que 4 % de la fertilisation azotée. Avec une teneur en azote de 21 % seulement, il a été peu à peu remplacé comme engrais universel par des produits plus concentrés, notamment l'urée et le nitrate d'ammonium. Obtenu pour plus de 40 % comme sous-produit dans la synthèse de monomères comme le caprolactame, l'acrylonitrile ou le méthacrylate de méthyle, et pour près de 10 % dans le traitement des gaz de cokerie, sa production dépend largement des développements du marché des fibres synthétiques, et, dans une moindre mesure, de la sidérurgie et de la métallurgie. Dans les pays développés, où la production est essentiellement fatale, le volume du marché est et sera plus fonction de la disponibilité du sulfate d'ammonium que de la demande ou de facteurs de marché; sa consommation ne résidera plus que dans des applications spécifiques pour lesquelles il sera bien adapté. Par contre, l'intérêt croissant pour compenser le déficit en soufre de certains sols, et les qualités agronomiques propres du sulfate d'ammonium laissent entrevoir la possibilité d'un essor de son utilisation dans certaines régions en voie de développernent. Ammonium sulfate was the most worldwide nitrogenous fertilizer used up to 1970. Today, it makes up only 4% of nitrogenous fertilization. With a nitrogen content of only 21%, it has gradually been replaced as a universal fertilizer by more concentrated products, particularly urea and ammonium nitrate. More than 40% of the ammonium sulfate is obtained as a by-product from the synthesis of monomers such as caprolactam, acrylonitrile or methyl methacrylate, and nearly 10% from coking gas processing. Its production depends extensively on the development of the market for synthetic fibers and, to a lesser extent, on the steel and metallurgical industries. In the industrialized countries

  20. Chemical Data for Precipitate Samples

    Science.gov (United States)

    Foster, Andrea L.; Koski, Randolph A.

    2008-01-01

    During studies of sulfide oxidation in coastal areas of Prince William Sound in 2005, precipitate samples were collected from onshore and intertidal locations near the Ellamar, Threeman, and Beatson mine sites (chapter A, fig. 1; table 7). The precipitates include jarosite and amorphous Fe oxyhydroxide from Ellamar, amorphous Fe oxyhydroxide from Threeman, and amorphous Fe oxyhydroxide, ferrihydrite, and schwertmannite from Beatson. Precipitates occurring in the form of loose, flocculant coatings were harvested using a syringe and concentrated in the field by repetitive decanting. Thicker accumulations were either scraped gently from rocks using a stainless steel spatula or were scooped directly into receptacles (polyethylene jars or plastic heavy-duty zippered bags). Most precipitate samples contain small amounts of sedimentary detritus. With three jarosite-bearing samples from Ellamar, an attempt was made to separate the precipitate from the heavy-mineral fraction of the sediment. In this procedure, the sample was stirred in a graduated cylinder containing deionized water. The jarosite-rich suspension was decanted onto analytical filter paper and air dried before analysis. Eleven precipitate samples from the three mine sites were analyzed in laboratories of the U.S. Geological Survey (USGS) in Denver, Colorado (table 8). Major and trace elements were determined by inductively coupled plasma-mass spectrometry following multiacid (HCl-HNO3-HClO4-HF) digestion (Briggs and Meier, 2002), except for mercury, which was analyzed by cold-vapor atomic absorption spectroscopy (Brown and others, 2002a). X-ray diffraction (XRD) analyses were performed on powdered samples (<200 mesh) by S. Sutley of the USGS. Additional details regarding sample preparation and detection limits are found in Taggert (2002). Discussions of the precipitate chemistry and associated microbial communities are presented in Koski and others (2008) and Foster and others (2008), respectively.

  1. Deuterium distribution regularities in precipitation

    International Nuclear Information System (INIS)

    Feurdean, V.; Feurdean, Lucia

    1999-01-01

    Deuterium measurements from precipitations were initiated by dr. L. Blaga in Natural Isotopic Abundances Department of ITIM since 1971. Systematic measurements of deuterium content and quantities of precipitations were carried on after 1975. Deuterium measurements from precipitations evidenced the succession of minimum values corresponding to cold seasons and maximum values corresponding to warm seasons. Other minimum and maximum values having lower amplitude than those corresponding to seasons are recorded for each season, too. As a rule, minimum values recorded during the summer months are the consequence of the penetration of cold air masses and maximum values recorded during the winter months are the consequence of penetration of the warm air masses. For the northwestern part of Romania including the Cluj-Napoca area, the winter precipitations come prevalently from the northwestern direction (from Greenland and North of Atlantic Ocean). The maximum values of deuterium content recorded during winter months are due to the displacements of warm and humid air masses from southwestern Europe (Mediterranean Sea). During long-time, (over 22 years) the monthly mean values of deuterium concentrations from precipitations for each year show amplitude variation of the minimum and maximum values. These maximum and minimum values, respectively, are oscillatory with a variable period of a few years (from 2 to 6 years). The variation of the oscillation period suggests at least two causes having different and fixed periodicity. The determinations of deuterium concentration from precipitations reveal the existence of natural isotopic label process for all waters natural. This phenomenon is adequate for the use of deuterium as a natural tracer in hydrologic studies. The isotopic hydrology adds new information to the hydrologic data base. The correlation between isotopic data base for precipitations and meteorological information will provide a new method for long term weather

  2. Recent Advances in the Synthesis of Ammonium-Based Rotaxanes

    Directory of Open Access Journals (Sweden)

    Dominic Thibeault

    2010-05-01

    Full Text Available The number of synthetic methods enabling the preparation of ammonium-based rotaxanes has increased very rapidly in the past ten years. The challenge in the synthesis of rotaxanes results from the rather weak interactions between the ammonium-containing rod and the crown ether macrocycle in the pseudorotaxane structure that rely mostly on O•H hydrogen bonds. Indeed, no strong base or polar solvent that could break up H-bonding can be used during the formation of rotaxanes because the two components will separate as two distinct entities. Moreover, most of the reactions have to be performed at room temperature to favor the formation of pseudorotaxane in solution. These non-trivial prerequisites have been taken into account to develop efficient reaction conditions for the preparation of rotaxanes and those are described in detail along this review.

  3. Influence quaternary ammonium salt in the organophilization of an bentonite

    International Nuclear Information System (INIS)

    Oliveira, S.V.; Alves, G.P.; Wanderley, A.S.D.; Araujo, E.M.

    2011-01-01

    Clays are natural materials, earthy, fine-grained particles with diameters generally less than 2μm, and formed by chemically hydrated silicates of aluminum, iron and magnesium. The clays have a range of applications, both in pottery and in other technology areas. This work aimed to study the influence of a quaternary ammonium salt to increase the basal distance of a bentonite clay powder obtained thereby promoting to a new structural profile characteristic with organoclay. The bentonite clay was treated with salt Praepragem WB. The following methods were used: X-ray diffraction (XRD) and X-ray fluorescence (XRF). The results indicated the intercalation of ammonium ions of the salt studied within the layers of silicate and expansion of basal spacing d 001 , ie the clay in the study showed 2θ angle shifts to smaller angles, indicating that the clay was organophilization. (author)

  4. A software nitrate sensor based on ammonium and redox signals.

    Science.gov (United States)

    Cecil, D

    2003-01-01

    We have computed the nitrate concentration in the activated sludge in real-time using a model, which is a subset of ASM1. The model is in operation at two WWTPs where oxygen, ammonium and redox are measured online in the aeration tanks. The model uses these measurements to continuously adjust its values for the influent ammonium concentration, the nitrification rate, the denitrification rate and the net hydrolysis. Then it computes the nitrate concentration. This value is updated every 10 s. The model results have been compared with the output from a Dr Lange in-situ nitrate sensor at one of these WWTPs. The systematic difference between these two measurements is less than 0.2 mgN L(-1) and 90% of the differences are between -1.1 and 1.1 mgN L(-1).

  5. Preparation of nanodispersed titania using stabilized ammonium nitrate melts

    KAUST Repository

    Raciulete, Monica

    2010-10-01

    An expedite one-step approach using simple precursors has been proposed to obtain metallic oxide compounds and exemplified by preparation of highly dispersed TiO2. The technique consists in heating to 400500 °C of molten ammonium nitrate stabilized with an organic nitrogen-containing compound (urea, melamine, ammonium oxalate) and containing dissolved metal salt precursor (TiOCl2). The crystallites of the resulting TiO2 demonstrated variable size and shape as a function of stabilizer used. Their activity in photocatalytic oxidation of formic acid also depends on the nature of the stabilizer. The catalysts as-prepared showed high photocatalytic performance, superior to that of the Degussa P25 reference. Nitrogen containing stabilizers play a double role of increasing the process safety and modifying the properties of the solid products. © 2010 Elsevier Inc. All rights reserved.

  6. Mammalian phospholipase D: activation by ammonium sulfate and nucleotides.

    OpenAIRE

    Nakamura, S; Shimooku, K; Akisue, T; Jinnai, H; Hitomi, T; Kiyohara, Y; Ogino, C; Yoshida, K; Nishizuka, Y

    1995-01-01

    Phospholipase D (PLD) associated with the rat kidney membrane was activated by guanine 5'-[gamma-thio]triphosphate and a cytosol fraction that contained ADP-ribosylation factor. When assayed by measuring the phosphatidyl transfer reaction to ethanol with exogenously added radioactive phosphatidylcholine as substrate, the PLD required a high concentration (1.6 M) of ammonium sulfate to exhibit high enzymatic activity. Other salts examined were far less effective or practically inactive, and th...

  7. Pseudoideal detonation of mechanoactivated mixtures of ammonium perchlorate with nanoaluminum

    Science.gov (United States)

    Shevchenko, A. A.; Dolgoborodov, A. Yu; Brazhnikov, M. A.; Kirilenko, V. G.

    2018-01-01

    Detonation properties of mechanochemical activated ammonium perchlorate with aluminum (AP–Al) mixtures with increased detonation velocity was studied. For compositions with nanoscale aluminum was obtained nonmonotonic dependence of the detonation velocity vs reciprocal diameter. The results generally showed that the combined usage of mechanical activation and nanoscale components of explosive mixtures can significantly increase the detonation ability and reduce the critical diameter to d cr = 7 mm.

  8. Nanomodified vermiculite NMV - a new material for recycling ammonium nitrogen

    Science.gov (United States)

    Rama, Miradije; Laiho, Taina; Eklund, Olav; Lehto, Kirsi; Shebanov, Alex; Smått, Jan-Henrik

    2016-04-01

    Vermiculites ((Mg,Fe,Al)3(Al,Si)4O10(OH)24H2O) are naturally occurring minerals from hydromica group with a high cation exchange capacity and large surface area. Since vermiculite is a hydrated mineral, its structure can be changed with heat. In this study vermiculite samples were heated in an oven until the interlayer distance of them diminished from 14 Å to 11.7 Å. This method for improving vermiculites intake of ammonium ions by heating, is an invention made at the University of Turku. Nanomodified vermiculite (NMV) is able to absorb up to 4.7 wt% of ammonium. NMV can be used as an efficient filter and immobilizer of ammonium in different environments. NMV has been efficiently tested on waste water from a biogas plant, human urine, combustion experiments, industrial chimneys, excrements from farms etc. Ammonium doped vermiculite (ADV) is further developed for fertilizer use. Performed experiments have testified the usability of ADV as a fertilizer. At first step the NMV was processed with the reject water from a biogas plant, were it absorbed NH4+ into the lattice. At second, the ADV was used as nutrient source for garden plants. Geraniums and begonias were used as test plants of the work. Plant growth rate was evaluated based on plant weight. Results showed that significant increase of the growth of geraniums and of begonias were observed when comparing to those cultivations where plants have got normal fertilization. Moreover, ADV has been tested as a fertilizer in greenhouse experiments with spruces and pines. After five months, the weight of the plants that had grown in a substrate containing ADV was 10 times the weight of plants growing in the reference substrate.

  9. Development of antibacterial quaternary ammonium silane coatings on polyurethane catheters

    Czech Academy of Sciences Publication Activity Database

    Zanini, S.; Polissi, A.; Maccagni, E.A.; Dell'Orto, E.C.; Liberatore, Chiara; Riccardi, C.

    2015-01-01

    Roč. 451, Aug (2015), 78-84 ISSN 0021-9797 R&D Projects: GA MŠk EE2.3.20.0143 Grant - others:OP VK 6(XE) CZ.1.07/2.3.00/20.0143 Institutional support: RVO:68378271 Keywords : plasma-induced graft-polymerization * acrylic acid * ATR/FTIR * AFM * quaternary ammonium silane * Escherichia coli Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.782, year: 2015

  10. Ammonium photo-production by heterocytous cyanobacteria: potentials and constraints.

    Science.gov (United States)

    Grizeau, Dominique; Bui, Lan Anh; Dupré, Catherine; Legrand, Jack

    2016-08-01

    Over the last decades, production of microalgae and cyanobacteria has been developed for several applications, including novel foods, cosmetic ingredients and more recently biofuel. The sustainability of these promising developments can be hindered by some constraints, such as water and nutrient footprints. This review surveys data on N2-fixing cyanobacteria for biomass production and ways to induce and improve the excretion of ammonium within cultures under aerobic conditions. The nitrogenase complex is oxygen sensitive. Nevertheless, nitrogen fixation occurs under oxic conditions due to cyanobacteria-specific characteristics. For instance, in some cyanobacteria, the vegetative cell differentiation in heterocyts provides a well-adapted anaerobic microenvironment for nitrogenase protection. Therefore, cell cultures of oxygenic cyanobacteria have been grown in laboratory and pilot photobioreactors (Dasgupta et al., 2010; Fontes et al., 1987; Moreno et al., 2003; Nayak & Das, 2013). Biomass production under diazotrophic conditions has been shown to be controlled by environmental factors such as light intensity, temperature, aeration rate, and inorganic carbon concentration, also, more specifically, by the concentration of dissolved oxygen in the culture medium. Currently, there is little information regarding the production of extracellular ammonium by heterocytous cyanobacteria. This review compares the available data on maximum ammonium concentrations and analyses the specific rate production in cultures grown as free or immobilized filamentous cyanobacteria. Extracellular production of ammonium could be coupled, as suggested by recent research on non-diazotrophic cyanobacteria, to that of other high value metabolites. There is little information available regarding the possibility for using diazotrophic cyanobacteria as cellular factories may be in regard of the constraints due to nitrogen fixation.

  11. Proton- and ammonium- sensing by histaminergic neurons controlling wakefulness.

    Directory of Open Access Journals (Sweden)

    Yvgenij eYanovsky

    2012-04-01

    Full Text Available Orexinergic and histaminergic neurons in the posterior hypothalamus are involved in the control of arousal. Extracellular levels of acid /CO2 are fundamental physicochemical signals controlling wakefulness and breathing. Acidification excites orexinergic neurons like the chemosensory neurons in the brain stem. Hypercapnia induces c-Fos expression, a marker for increased neuronal activity, in the rat histaminergic tuberomamillary nucleus (TMN, but the mechanisms of this excitation are unknown. Acid-sensing ion channels (ASICs are gated by protons and also by ammonium. Recordings in rat brain slices revealed now that acidification within the physiological range (pH from 7.3 to 7.0 as well as ammonium chloride (5mM excite histaminergic neurons. We detected variable combinations of 4 known types of ASICs in single TMN neurons, along with the pharmacological properties of pH-induced current. At pH 7.0 however, activation of ASICs in TMN neurons was negligible. Block of type I metabotropic glutamate receptors abolished proton- but not ammonium- induced excitation. Mouse TMN neurons were identified within a novel HDC-Cre transgenic reporter mouse line. In contrast to the rat these lacked pH 7.0-induced excitation and showed only a minimal response to the mGluR I agonist DHPG (0.5µM. Ammonium-induced excitation was similar in mouse and rat. Thus glutamate, which is released by glial cells and orexinergic axons amplifies CO2/acid-induced arousal through the recruitment of the histaminergic system in rat but not in mouse. These results are relevant for the understanding of neuronal mechanisms controlling H+/CO2-induced arousal in hepatic encephalopathy and obstructive sleep apnoea. The new HDC-Cre mouse model will be a useful tool for studying the physiological and pathophysiological roles of the histaminergic system.

  12. nitrate-nitrogen and ammonium- nitrogen levels of some water ...

    African Journals Online (AJOL)

    NaREM

    Key words: Nitrate, ammonium, water bodies/quality, soils, Douala metropolis. ... This has initiated progressive degradation of land and other vital resources .... 2.74 35.0 30.8. Downstream. Wouri Bridge. WOU6. 04 03 59.9N. 009 41 36.3E. 7.3. 6960. 0.11 39.2 22.4. Wouri Wharf. WOU7. 04 02 27.8N. 009 40 23.9E. 7.4. 9600.

  13. Ammonium ionic liquids as green solvents for drugs 

    OpenAIRE

    Melo, Catarina I.; Bogel-Lukasik, R.; Ponte, Manuel Nunes; Bogel-Lukasik, Ewa

    2013-01-01

    A high solubility of antituberculosis antibiotic drugs: isoniazid and pyrazinecarboxamide in ammonium ionic liquids shown in this work, demonstrates the promising perspectives in the drug processing. Solid–liquid equilibrium (SLE) measurements have been made using a dynamic (synthetic) method. Thermophyscial properties such as melting point, enthalpy of fusion, temperatures of phase transitions and corresponding enthalpies for both isoniazid and pyrazinecarboxamide as well as for thre...

  14. Extraction Factor Of Pure Ammonium Paratungstate From Tungsten Scraps

    Directory of Open Access Journals (Sweden)

    Pee J.-H.

    2015-06-01

    Full Text Available Typical oxidation process of tungsten scraps was modified by the rotary kiln with oxygen burner to increase the oxidation rate of tungsten scraps. Also to accelerate the solubility of solid oxidized products, the hydrothermal reflux method was adapted. By heating tungsten scraps in rotary kiln with oxygen burner at around 900° for 2hrs, the scraps was oxidized completely. Then oxidized products (WO3 and CoWO4 was fully dissolved in the solution of NaOH by hydrothermal reflux method at 150° for 2hrs. The dissolution rate of oxidized products was increased with increasing the reaction temperature and concentration of NaOH. And then CaWO4 and H2WO4 could be generated from the aqueous sodium tungstate solution. Ammonium paratungstate (APT also could be produced from tungstic acid using by aqueous ammonium solution. The morphologies (cubic and plate types of APT was controlled by the stirring process of purified solution of ammonium paratungstate.

  15. Airborne ammonia and ammonium within the Northern Adriatic area, Croatia.

    Science.gov (United States)

    Alebic-Juretic, Ana

    2008-08-01

    Determination of airborne ammonia started in the early 1980s, as a part of air pollution monitoring of industrial plants. Due to high emissions, the city of Rijeka was one of the most polluted in Croatia in the mid-1980s. Considerable reductions in SO2 and NO(x) emissions led to lower airborne levels of these pollutants in the mid 1990s. In spite of the coke plant closure in 1994, there was only a weak decline in airborne ammonia over the period 1980--2005, with annual means in the range of 12-20 microg m(-3) at urban Site 1 and 6-28 microg m(-3) at suburban Site 2. Similar behaviour has been observed with ammonium in bulk rainwater samples since 1996. Higher and approximately equal deposition of nitrogen as ammonium (N-NH4+) were obtained for the urban Site 1 and the mountainous Site 4, but with different causative facts. Ammonium's contribution to total nitrogen (NO3(-)+NH4+) deposition is approximately two thirds, even for a remote Site 3.

  16. Removing ammonium from water and wastewater using cost-effective adsorbents: A review.

    Science.gov (United States)

    Huang, Jianyin; Kankanamge, Nadeeka Rathnayake; Chow, Christopher; Welsh, David T; Li, Tianling; Teasdale, Peter R

    2018-01-01

    Ammonium is an important nutrient in primary production; however, high ammonium loads can cause eutrophication of natural waterways, contributing to undesirable changes in water quality and ecosystem structure. While ammonium pollution comes from diffuse agricultural sources, making control difficult, industrial or municipal point sources such as wastewater treatment plants also contribute significantly to overall ammonium pollution. These latter sources can be targeted more readily to control ammonium release into water systems. To assist policy makers and researchers in understanding the diversity of treatment options and the best option for their circumstance, this paper produces a comprehensive review of existing treatment options for ammonium removal with a particular focus on those technologies which offer the highest rates of removal and cost-effectiveness. Ion exchange and adsorption material methods are simple to apply, cost-effective, environmentally friendly technologies which are quite efficient at removing ammonium from treated water. The review presents a list of adsorbents from the literature, their adsorption capacities and other parameters needed for ammonium removal. Further, the preparation of adsorbents with high ammonium removal capacities and new adsorbents is discussed in the context of their relative cost, removal efficiencies, and limitations. Efficient, cost-effective, and environmental friendly adsorbents for the removal of ammonium on a large scale for commercial or water treatment plants are provided. In addition, future perspectives on removing ammonium using adsorbents are presented. Copyright © 2017. Published by Elsevier B.V.

  17. Cesium removal from liquid acidic wastes with the primary focus on ammonium molybdophosphate as an ion exchanger: A literature review

    International Nuclear Information System (INIS)

    Miller, C.J.

    1995-03-01

    Many articles have been written concerning the selective removal of cesium from both acidic and alkaline defense wastes. The majority of the work performed for cesium removal from defense wastes involves alkaline feed solutions. Several different techniques for cesium removal from acidic solutions have been evaluated such as precipitation, solvent extraction, and ion exchange. The purpose of this paper is to briefly review various techniques for cesium removal from acidic solutions. The main focus of the review will be on ion exchange techniques, particularly those involving ammonium molybdophosphate as the exchanger. The pertinent literature sources are condensed into a single document for quick reference. The information contained in this document was used as an aid in determining techniques to evaluate cesium removal from the acidic Idaho Chemical Processing Plant waste matrices. 47 refs., 2 tabs

  18. Synthesis of CNTs/CuO and its catalytic performance on the thermal decomposition of ammonium perchlorate

    Directory of Open Access Journals (Sweden)

    Ping Cui

    2016-05-01

    Full Text Available Copper oxide (CuO nanoparticles were successfully deposited on carbon nanotubes’ (CNTs surface via complex-precipitation method, the nanocomposite was characterized by transmission electron microscopy (TEM, scanning electron microscopy (SEM, X-ray photoelectron spectroscopy (XPS, X-ray powder diffraction (XRD, Raman spectroscopy, Fourier transform infrared (FT-IR and Brunauer–Emmett–Teller (BET. The catalytic performance of CNTs/CuO on ammonium perchlorate (AP decomposition was analyzed by differential thermal analyzer (DTA, the DTA results showed its excellent catalytic effect on AP decomposition, as 8 wt.% CNTs/CuO was added in AP, the second exothermic peak temperature decreased by 158 °C. Such composite may be a promising candidate for catalyzing the AP thermal decomposition.

  19. Cesium removal from liquid acidic wastes with the primary focus on ammonium molybdophosphate as an ion exchanger: A literature review

    Energy Technology Data Exchange (ETDEWEB)

    Miller, C.J.

    1995-03-01

    Many articles have been written concerning the selective removal of cesium from both acidic and alkaline defense wastes. The majority of the work performed for cesium removal from defense wastes involves alkaline feed solutions. Several different techniques for cesium removal from acidic solutions have been evaluated such as precipitation, solvent extraction, and ion exchange. The purpose of this paper is to briefly review various techniques for cesium removal from acidic solutions. The main focus of the review will be on ion exchange techniques, particularly those involving ammonium molybdophosphate as the exchanger. The pertinent literature sources are condensed into a single document for quick reference. The information contained in this document was used as an aid in determining techniques to evaluate cesium removal from the acidic Idaho Chemical Processing Plant waste matrices. 47 refs., 2 tabs.

  20. Extraction of Vanadium from Vanadium Slag Via Non-salt Roasting and Ammonium Oxalate Leaching

    Science.gov (United States)

    Li, Meng; Du, Hao; Zheng, Shili; Wang, Shaona; Zhang, Yang; Liu, Biao; Dreisinger, David Bruce; Zhang, Yi

    2017-10-01

    A clean method featuring non-salt roasting followed by (NH4)2C2O4 leaching to recover vanadium from vanadium slag was proposed. The carcinogenic Cr6+ compounds and exhaust gases were avoided, and the water generated from vanadate precipitation may be recycled and reused in this new leaching process. The leaching residues may be easily used by a blast furnace. Moreover, (NH4)2C2O4 solution was used as a leaching medium to avoid expensive and complicated ammonium controlling operations as a result of the stability of (NH4)2C2O4 at a high temperature. The transformation mechanisms of vanadium- and chromium-bearing phases were systematically investigated by x-ray diffraction analysis and scanning electron microscopy with energy-disperse x-ray spectrometry, respectively. In addition, the effects of oxygen concentration, roasting temperature, and holding time on vanadium recovery were investigated. Finally, the effects of leaching variables on the vanadium leaching rate were also examined.

  1. Atomic absorption spectroscopic, conductometric and colorimetric methods for determination of some fluoroquinolone antibacterials using ammonium reineckate

    Science.gov (United States)

    Al-Ghannam, Sheikha M.

    2008-04-01

    Three accurate, rapid and simple atomic absorption spectrometric (AAS), conductometric and colorimetric methods were developed for the determination of gatifloxacin (GTF), moxifloxacin (MXF) and sparfloxacin (SPF). The proposed methods depend upon the reaction of ammonium reineckate with the studied drugs to form stable precipitate of ion-pair complexes, which was dissolved in acetone. The pink coloured complexes were determined either by AAS or colorimetrically at λmax 525 nm directly using the dissolved complex. Using conductometric titration, the studied drugs could be evaluated in 50% (v/v) acetone. The optimizations of various experimental conditions were described. Optimum concentration ranges for the determination of GTF, MXF and SPF were 5.0-150, 40-440 μg mL -1 and 0.10-1.5 mg mL -1 using atomic absorption (AAS), conductometric and colorimetric methods, respectively. Detection and quantification limits are ranges from 1.5 to 2.3 μg mL -1 using AAS method or 30-45 μg mL -1 using colorimetric method. The proposed procedures have been applied successfully to the analysis of these drugs in pharmaceutical formulations and the results are favourably comparable to the reference methods.

  2. Precipitation process for supernate decontamination

    International Nuclear Information System (INIS)

    Lee, L.M.; Kilpatrick, L.L.

    1982-11-01

    A precipitation and adsorption process has been developed to remove cesium, strontium, and plutonium from water-soluble, high-level radioactive waste. An existing waste tank serves as the reaction vessel and the process begins with the addition of a solution of sodium tetraphenylborate and a slurry of sodium titanate to the contained waste salt solution. Sodium tetraphenylborate precipitates the cesium and sodium titanate adsorbs the strontium and plutonium. The precipitate/adsorbate is then separated from the decontaminated salt solution by crossflow filtration. This new process offers significant capital savings over an earlier ion exchange process for salt decontamination. Chemical and small-scale engineering studies with actual waste are reported. The effect of many variables on the decontamination factors and filter performance are defined

  3. Treatment of the effluent generated in conversion process of auc by precipitation

    International Nuclear Information System (INIS)

    Carvalho, E.F.U. de; Santos, L.R. dos; Riella, H.G.

    1988-01-01

    The purpose of this study is to provide a description for the treatment of generating effluent from Ammonium Uranyl Carbonate-AUC IPEN/CNEN-SP. This procedure describes the uranium recovery (200 mlU/1) by means of its precipitation with hidrogen peroxide at 50 0 C, pH 8,5 where results a yellow powder thought to be UO 4 2NH 3 2HF and a NH 4 F solution with an uranium concentration of 6-7mgU/1. The powder resulted was characterized by chemical analysis and X- Ray difraction techniques. (author) [pt

  4. γ-Aminobutyric acid addition alleviates ammonium toxicity by limiting ammonium accumulation in rice (Oryza sativa) seedlings.

    Science.gov (United States)

    Ma, Xiaoling; Zhu, Changhua; Yang, Na; Gan, Lijun; Xia, Kai

    2016-12-01

    Excessive use of nitrogen (N) fertilizer has increased ammonium (NH 4 + ) accumulation in many paddy soils to levels that reduce rice vegetative biomass and yield. Based on studies of NH 4 + toxicity in rice (Oryza sativa, Nanjing 44) seedlings cultured in agar medium, we found that NH 4 + concentrations above 0.75 mM inhibited the growth of rice and caused NH 4 + accumulation in both shoots and roots. Use of excessive NH 4 + also induced rhizosphere acidification and inhibited the absorption of K, Ca, Mg, Fe and Zn in rice seedlings. Under excessive NH 4 + conditions, exogenous γ-aminobutyric acid (GABA) treatment limited NH 4 + accumulation in rice seedlings, reduced NH 4 + toxicity symptoms and promoted plant growth. GABA addition also reduced rhizosphere acidification and alleviated the inhibition of Ca, Mg, Fe and Zn absorption caused by excessive NH 4 + . Furthermore, we found that the activity of glutamine synthetase/NADH-glutamate synthase (GS; EC 6.3.1.2/NADH-GOGAT; EC1.4.1.14) in root increased gradually as the NH 4 + concentration increased. However, when the concentration of NH 4 + is more than 3 mM, GABA treatment inhibited NH 4 + -induced increases in GS/NADH-GOGAT activity. The inhibition of ammonium assimilation may restore the elongation of seminal rice roots repressed by high NH 4 + . These results suggest that mitigation of ammonium accumulation and assimilation is essential for GABA-dependent alleviation of ammonium toxicity in rice seedlings. © 2016 Scandinavian Plant Physiology Society.

  5. On the Mass Balance of Asphaltene Precipitation

    DEFF Research Database (Denmark)

    Andersen, Simon Ivar; Lira-Galeana, C.; Stenby, Erling Halfdan

    2001-01-01

    are performed in order to check the consistency of mass balances within asphaltene precipitation. Asphaltenes are precipitated in two step processes either by changing temperature or by changes in precipitant with increasing precipitation power. This has been performed for three different oils. The data...

  6. Kinetics of asphaltene precipitation from crude oils

    Energy Technology Data Exchange (ETDEWEB)

    Maqbool, T.; Hussein, I.A.; Fogler, H.S. [Michigan Univ., Ann Arbor (United States). Dept. of Chemical Engineering

    2008-07-01

    The kinetics of asphaltene precipitation from crude oils was investigated using n-alkane precipitants. Recent studies have shown that there is a kinetic phenomenon associated with asphaltene precipitation. This study showed that the time needed to precipitate the asphaltenes can vary from a few minutes to several months, depending on the amount of n-alkane precipitant added. As such, the onset of asphaltene precipitation is a function of the concentration of precipitant and time. A technique to quantify the amount of asphaltenes precipitated as a function of time and precipitant concentration was presented. This study also investigated the kinetic effects caused by various precipitants. Optical microscopy was used to monitor the growth of asphaltene aggregates with time. Refractive index measurements provided further insight into the kinetics of asphaltene precipitation. Polarity based fractionation and dielectric constant measurements were used to compare the nature of asphaltenes precipitated early in the precipitation process with the asphaltenes precipitated at later times. It was concluded that asphaltenes precipitating at different times from the same crude oil-precipitant mixture are different from one another. 3 refs.

  7. Radar-Derived Quantitative Precipitation Estimation Based on Precipitation Classification

    Directory of Open Access Journals (Sweden)

    Lili Yang

    2016-01-01

    Full Text Available A method for improving radar-derived quantitative precipitation estimation is proposed. Tropical vertical profiles of reflectivity (VPRs are first determined from multiple VPRs. Upon identifying a tropical VPR, the event can be further classified as either tropical-stratiform or tropical-convective rainfall by a fuzzy logic (FL algorithm. Based on the precipitation-type fields, the reflectivity values are converted into rainfall rate using a Z-R relationship. In order to evaluate the performance of this rainfall classification scheme, three experiments were conducted using three months of data and two study cases. In Experiment I, the Weather Surveillance Radar-1988 Doppler (WSR-88D default Z-R relationship was applied. In Experiment II, the precipitation regime was separated into convective and stratiform rainfall using the FL algorithm, and corresponding Z-R relationships were used. In Experiment III, the precipitation regime was separated into convective, stratiform, and tropical rainfall, and the corresponding Z-R relationships were applied. The results show that the rainfall rates obtained from all three experiments match closely with the gauge observations, although Experiment II could solve the underestimation, when compared to Experiment I. Experiment III significantly reduced this underestimation and generated the most accurate radar estimates of rain rate among the three experiments.

  8. The characterisation of precipitated magnetites

    International Nuclear Information System (INIS)

    Rush, D.F.; Segal, D.L.

    1982-06-01

    Methods are described for the preparation of magnetite by precipitation from aqueous solutions of iron(II) and iron(III) salts. The magnetites have been characterised by transmission electron microscopy, chemical analysis and X-ray diffraction. Transmission Moessbauer spectroscopy has also been used to characterise precipitated magnetites and a comparison of the spectra has been made with those obtained from nickel ferrite and hydrated ferric oxides. The hydrothermal stability of magnetite at 573 K has also been investigated. This work is relevant to corrosion processes that can occur in the water coolant circuits of nuclear reactors. (author)

  9. An Improved Plutonium Trifluoride Precipitation Flowsheet

    Energy Technology Data Exchange (ETDEWEB)

    Harmon, H.D.

    2001-06-26

    This report discusses results of the plutonium trifluoride two-stage precipitation study. A series of precipitation experiments was used to identify the significant process variables affecting precipitation performance. A mathematical model of the precipitation process was developed which is based on the formation of plutonium fluoride complexes. The precipitation model relates all process variables, in a single equation, to a single parameter which can be used to control the performance of the plutonium trifluoride precipitation process. Recommendations have been made which will optimize the FB-Line plutonium trifluoride precipitation process.

  10. Two-stage precipitation of cerium trifluoride

    International Nuclear Information System (INIS)

    Luerkens, D.W.

    1984-04-01

    Cerium was used as a surrogate for plutonium in studies of the solubility and precipitation of the trifluoride salt. Cerium trifluoride was precipitated using a two-stage precipitation system. A series of precipitation experiments were used to identify the significant process variables affecting precipitate characteristics. A mathematical precipitation model was developed which is based on the formation of cerium fluoride complexes. The precipitation model relates all process variables, in a single equation, to a single parameter which can be used to control particle characteristics. 11 references, 9 figures, 8 tables

  11. Utilization of microbial induced calcite precipitation for sand consolidation and mortar crack remediation

    Directory of Open Access Journals (Sweden)

    S.A. Abo-El-Enein

    2012-12-01

    Full Text Available The microbes can hydrolyze urea by urease enzyme to produce ammonium as well as carbonate ions and in the presence of calcium ions which can precipitate calcium carbonate; this process is called “biocalcification” or microbial induced calcite precipitation (MICP.This technology is environmentally friendly not only because it gives strength to sand body, but also it allows water to penetrate to sand body, which is unlike silicate cement that will destroy the ecosystem of the earth. Calcium carbonate precipitated by bacteria acts as a binding material to sand particles, so incompact sand will be consolidated. Calcium chloride, calcium acetate and calcium nitrate (1 M as calcium sources were tested for their ability to consolidate sand by mixing with urea (1 M and bacteria cells (one optical density, 1 OD. The key point of this study aimed to choose the suitable calcium source which produces higher compressive strength and lower water absorption. The results showed that the degree of crystallinity and amount of precipitated calcium carbonate, as well as the consequent increase in strength of consolidated sand, in case of calcium chloride medium are higher than those precipitated in case of calcium acetate as well as calcium nitrate media. In addition, consolidated sand by calcium chloride was also used for cement mortar crack remediation.

  12. Comparison of characteristics of hydroxyapatite powders synthesized from cuttlefish bone via precipitation and ball milling techniques

    Science.gov (United States)

    Faksawat, K.; Kaewwiset, W.; Limsuwan, P.; Naemchanthara, K.

    2017-09-01

    The aim of this work was to compare characteristics of hydroxyapatite synthesized by precipitation and ball milling techniques. The cuttlefish bone powder was a precursor in calcium source and the di ammonium hydrogen orthophosphate powders was a precursor in phosphate source. The hydroxyapatite was synthesized by the both techniques such as precipitation and ball milling techniques. The phase formation, chemical structure and morphology of the both hydroxyapatite powders have been examined by X-ray diffractometer (XRD), Fourier transform infrared spectroscope (FTIR) and field emission scanning electron microscope (FESEM), respectively. The results show that the hydroxyapatite synthesized by precipitation technique formed hydroxyapatite phase slower than the hydroxyapatite synthesized by ball milling technique. The FTIR results show the chemical structures of sample in both techniques are similar. The morphology of the hydroxyapatite from the both techniques were sphere like shapes and particle size was about in nano scale. The average particle size of the hydroxyapatite by ball milling technique was less than those synthesized by precipitation technique. This experiment indicated that the ball milling technique take time less than the precipitation technique in hydroxyapatite synthesis.

  13. Start-up of simultaneous removal of ammonium and sulfate from an anaerobic ammonium oxidation (anammox) process in an anaerobic up-flow bioreactor

    International Nuclear Information System (INIS)

    Yang Zhiquan; Zhou Shaoqi; Sun Yanbo

    2009-01-01

    A laboratory testing of simultaneous removal of ammonium and sulfate (SRAS) was studied from an anammox process in an anaerobic bioreactor filled with granular activated carbon. Two different phases of experiment were investigated to start up the SRAS process, and final batch tests were performed to analyze the SRAS process. The experiment included an anammox process and an SRAS process. During the anammox process, the highest removal efficiency of ammonium and nitrite was up to 97 and 98%, respectively. After 160 days in the stationary phase of anammox process, the ratio of ammonium to nitrite consumption was approximately 1:1.15, which is much higher than 1:1.32 in the traditional anammox process. The extra electron acceptor, such as sulfate, was thought to react with ammonium by bacteria. Synthetic wastewater containing ammonium chlorine and sodium sulfate was used as the feed for the bioreactor in the second phase of experiment. During the SRAS process, the influent concentrations of ammonium and sulfate were controlled to be 50-60 and 210-240 mg L -1 respectively. After start-up and acclimatization of this process for 60 days, the average effluent concentrations of ammonium and sulfate were 30 and 160 mg L -1 , respectively. The simultaneous ammonium and sulfate removal was detected in the reactor. In order to further validate the biochemical interaction between ammonium and sulfate, batch tests was carried out. Abiotic tests were carried out to demonstrate that the pure chemical action between ammonium and sulfate without microorganism was not possible. Biotic assays with different ammonium and sulfate concentrations were further investigated that high concentrations of ammonium and sulfate could promote simultaneous removal of ammonium and sulfate. And elemental sulfur and nitrogen gas as the products measured in the SRAS process helped to demonstrate the occurrence of new interaction between nitrogen and sulfur. The new process of SRAS in the inorganic

  14. Start-up of simultaneous removal of ammonium and sulfate from an anaerobic ammonium oxidation (anammox) process in an anaerobic up-flow bioreactor.

    Science.gov (United States)

    Yang, Zhiquan; Zhou, Shaoqi; Sun, Yanbo

    2009-09-30

    A laboratory testing of simultaneous removal of ammonium and sulfate (SRAS) was studied from an anammox process in an anaerobic bioreactor filled with granular activated carbon. Two different phases of experiment were investigated to start up the SRAS process, and final batch tests were performed to analyze the SRAS process. The experiment included an anammox process and an SRAS process. During the anammox process, the highest removal efficiency of ammonium and nitrite was up to 97 and 98%, respectively. After 160 days in the stationary phase of anammox process, the ratio of ammonium to nitrite consumption was approximately 1:1.15, which is much higher than 1:1.32 in the traditional anammox process. The extra electron acceptor, such as sulfate, was thought to react with ammonium by bacteria. Synthetic wastewater containing ammonium chlorine and sodium sulfate was used as the feed for the bioreactor in the second phase of experiment. During the SRAS process, the influent concentrations of ammonium and sulfate were controlled to be 50-60 and 210-240 mg L(-1) respectively. After start-up and acclimatization of this process for 60 days, the average effluent concentrations of ammonium and sulfate were 30 and 160 mg L(-1), respectively. The simultaneous ammonium and sulfate removal was detected in the reactor. In order to further validate the biochemical interaction between ammonium and sulfate, batch tests was carried out. Abiotic tests were carried out to demonstrate that the pure chemical action between ammonium and sulfate without microorganism was not possible. Biotic assays with different ammonium and sulfate concentrations were further investigated that high concentrations of ammonium and sulfate could promote simultaneous removal of ammonium and sulfate. And elemental sulfur and nitrogen gas as the products measured in the SRAS process helped to demonstrate the occurrence of new interaction between nitrogen and sulfur. The new process of SRAS in the inorganic

  15. Silica precipitation by synthetic minicollagens.

    Science.gov (United States)

    Weiher, Felix; Schatz, Michaela; Steinem, Claudia; Geyer, Armin

    2013-03-11

    Oligomeric Pro-Hyp-Gly- (POG-) peptides, wherein the collagenous triple helix is supported by C-terminal capping, exhibit silica precipitation properties (O, Hyp = (2S,4R)hydroxyproline). As quantified by a molybdate assay, the length of the covalently tethered triple helix (number of POG units) determines the amount of amorphous silica obtained from silicic acid solution. Although lacking charged side chains, the synthetic collagens precipitate large quantities of silicic acid resulting in micrometer-sized spheres of varying surface morphologies as analyzed by scanning electron microscopy. Similar precipitation efficiencies on a fast time scale of less than 10 min were previously described only for biogenic diatom proteins and sponge collagen, respectively, which have a considerably higher structural complexity and limited accessibility. The minicollagens described here provide an unexpected alternative to the widely used precipitation conditions, which generally depend on (poly-)amines in phosphate buffer. Collagen can form intimate connections with inorganic matter. Hence, silica-enclosed collagens have promising perspectives as composite materials.

  16. Rheology of tetraphenylborate precipitate slurry

    International Nuclear Information System (INIS)

    Goren, I.D.; Martin, H.D.; McLain, M.A.

    1985-01-01

    The rheological properties of tetraphenylborate precipitate slurry were determined. This nonradioactive slurry simulates the radioactive tetraphenylborate precipitate generated at the Savannah River Plant by the In-Tank Precipitation Process. The data obtained in this study was applied in the design of slurry pumps, transfer pumps, transfer lines, and vessel agitation for the Defense Waste Processing Facility and other High Level Waste treatment projects. The precipitate slurry behaves as a Bingham plastic. The yield stress is directly proportional to the concentration of insoluble solids over the range of concentrations studied. The consistency is also a linear function of insoluble solids over the same concentration range. Neither the yield stress nor the consistency was observed to be affected by the presence of the soluble solids. Temperature effects on flow properties of the slurry were also examined: the yield stress is inversely proportional to temperature, but the consistency of the slurry is independent of temperature. No significant time-dependent effects were found. 4 refs., 4 figs., 3 tabs

  17. Influence of heterogeneous ammonium availability on bacterial community structure and the expression of nitrogen fixation and ammonium transporter genes during in situ bioremediation of uranium-contaminated groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Mouser, P.J.; N' Guessan, A.L.; Elifantz, H.; Holmes, D.E.; Williams, K.H.; Wilkins, M.J.; Long, P.E.; Lovley, D.R.

    2009-04-01

    The impact of ammonium availability on microbial community structure and the physiological status and activity of Geobacter species during in situ bioremediation of uranium-contaminated groundwater was evaluated. Ammonium concentrations varied by as much as two orders of magnitude (<4 to 400 {micro}M) across the study site. Analysis of 16S rRNA gene sequences suggested that ammonium influenced the composition of the microbial community prior to acetate addition with Rhodoferax species predominating over Geobacter species at the site with the highest ammonium, and Dechloromonas species dominating at sites with lowest ammonium. However, once acetate was added, and dissimilatory metal reduction was stimulated, Geobacter species became the predominant organisms at all locations. Rates of U(VI) reduction appeared to be more related to the concentration of acetate that was delivered to each location rather than the amount of ammonium available in the groundwater. In situ mRNA transcript abundance of the nitrogen fixation gene, nifD, and the ammonium importer gene, amtB, in Geobacter species indicated that ammonium was the primary source of nitrogen during in situ uranium reduction, and that the abundance of amtB transcripts was inversely correlated to ammonium levels across all sites examined. These results suggest that nifD and amtB expression by subsurface Geobacter species are closely regulated in response to ammonium availability to ensure an adequate supply of nitrogen while conserving cell resources. Thus, quantifying nifD and amtB expression appears to be a useful approach for monitoring the nitrogen-related physiological status of Geobacter species in subsurface environments during bioremediation. This study also emphasizes the need for more detailed analysis of geochemical/physiological interactions at the field scale, in order to adequately model subsurface microbial processes.

  18. The influence of mountain meteorology on precipitation chemistry at low and high elevations of the Colorado Front Range, USA

    Science.gov (United States)

    Denning, A. Scott

    1993-01-01

    We explored the seasonal characteristics in wet deposition chemistry for two sites located at different elevations along the east slope of the Colorado Front Range in Rocky Mountain National Park. Seasonally separated precipitation was stratified into highly concentrated (high salt), dilute (low salt), or acid-dominated precipitation groups. These groups and unstratified precipitation data were related to mean easterly or westerly zonal winds to determine direction of local transport. Strong acid anion associations were also determined for the stratified and unstratified precipitation data sets. We found that strong acid anions, acidity, ammonium, and high salt concentrations originate to the east of Rocky Mountain National Park, and are transported via up-valley funneling winds or convective instability from differential heating of the mountains and the plains to the east. These influence the composition of precipitation at Beaver Meadows, the low elevation site, throughout the year, while their effect on precipitation at Loch Vale, the high elevation site, is felt most strongly during the summer. During the winter, Loch Vale precipitation is very dilute, and occurs in conjunction with westerly winds resulting from the southerly location of the jet stream.

  19. CRYSTALLIZATION KINETICS OF AMMONIUM PERCHLORATE IN AN AGITATED VESSEL

    Directory of Open Access Journals (Sweden)

    Nahidh Kaseer

    2013-05-01

    Full Text Available 31Overall crystal growth kinetics for ammonium perchlorate in laboratory scale batch  agitated vessel crystallizer have been determined from batch experiments performed in an integral mode. The effects of temperature between 30-60ºC, seed size 0.07, 0.120 and 0.275 mm and stirrer speed 160, 340, and 480 rpm, on the kinetics of crystal growth were investigated. Two different methods, viz. polynomial fitting and initial derivative were used to predict the kinetics expression. In general both methods gave comparable results for growth kinetics estimation. The order of growth process is not more than two. The activation energy for crystal growth of ammonium perchlorate was determined and found  to be equal to 5.8 kJ/ mole.            Finally, the influence of the affecting parameters on the crystal growth rate gives general expression that had an obvious dependence of the growth rate on each variables of concern (temperature, seed size, and stirrer speed .The general overall growth rate expression had shown that super saturation is the most significant variable. While the positive dependence of the stirrer speed demonstrates the importance of the diffusional step in the growth rate model. Moreover, the positive dependence of the seed size demonstrate the importance of the surface integration  step in the growth rate model. All the studied variables tend to suggest that the growth rate characteristics  of ammonium perchlorate from aqueous solution commenced in a batch crystallizer are diffusion kinetic controlled process.

  20. Regeneration of clinoptilolite zeolite used for the ammonium removal

    International Nuclear Information System (INIS)

    Garcia G, M.C.

    2002-01-01

    The use of zeolites has been increased in the last years with different applications and with a great boom in the environmental area, but a little had been make about the regeneration of such zeolites. The presence of nitrogen-ammonia in water may cause serious pollution problems since it results to be toxic for fishes and other aquatic life forms, also it provokes the algae growing. The natural clinoptilolite contains interchangeable ions such as the sodium (Na + ), potassium (K + ), magnesium (Mg 2+ ) and calcium (Ca 2+ ) in different proportions depending on the mineral origin When the zeolite is upgraded to its sodium form, the cation exchange capacity and the preference by the nitrogen-ammonia are increased, allowing the reversible process of sorption. In this work it was proposed the regeneration to its sodium form about the ammonia clinoptilolite zeolite. The natural mineral was characterized using the methods such as: X-ray diffraction, Infrared spectroscopy, Thermal gravimetric analysis and surface area. The results show that the ammonium sorption was between 95% and 98.7% such an ambient temperature as a flow back. the zeolite was regenerated approximately from 60% in the first cycle up to 97% in the last cycle at flow back temperature and of 59.2% up to 96.9% at ambient temperature, it was not presented any significant effect which could be attributed to the temperature. During the exchange process, the cations present in the natural zeolite were exchanged with the ammonium ions, this process was not completed due to that retained ammonium quantity was major that of the desorpted ions, what shows that in addition of ion exchange, another type of sorption process exists. (Author)

  1. Fabrication of Yttria Nanopowder by Precipitation Method Using Micro Meter Powder

    Directory of Open Access Journals (Sweden)

    M. Khajelakzay

    2015-12-01

    Full Text Available Precipitation has always been one of the important methods in the preparation of ceramic nanopowders. In this study, the most important parameters, ageing time and concentration parameters, have been studied. Yttrium oxide (Yttria nanopowder was synthesized by precipitation method. Yttria micropowder and ammonium hydrogen carbonate were used as precursor materials. The study involved aging time and concentration in four and three levels, repectively (3, 6, 12 and 24h for ageing time and 0.25, 0.5 and 0.75 mol/L for concentration. Synthesized phases, thermal behavior and particle size were studied by X-ray diffraction pattern (XRD, thermogravimetry (TG, differential thermal analysis (DTA and field emission scanning electron microscopy (FE-SEM. Fourier transform infrared spectroscopy analysis (FTIR was used for studying bonding before and after the heat treatment at 900, 1000 and 1100 °C.

  2. Optimization of the conditions for producing zirconia by the precipitation of basic zirconium sulfate

    International Nuclear Information System (INIS)

    Ricci, D.R.; Paschoal, J.O.A.

    1988-01-01

    The process of precipitation of the basic sulfate from zirconium oxychlorides solutions has been optimized in order to obtain zirconia of high purity as well as suitable for ceramic processing. The main parameters of this study were obtained from the determination of the pH and of the concentration of the initial oxychloride solution, of the sulfate/zirconium molar ratio and of the reaction temperature. The following experimental procedure has been carried out: a) reaction of each precipitate with ammonium hydroxide followed by drying at 150 0 -C / 5 h and calcination at 1000 0 C / 1 h, yielding the final product (zirconia) b) product characterization by means of spectrographic, X - ray fluorescence and diffractometry analyses, determination of grain size distribution and of apparent density, and morphology study by scanning electron microscopy. The yielding of the overall reaction has been determined by chemical analysis and the composition of the basic zirconium sulfate by thermogravimetric analyses. (author) [pt

  3. Synthesis of alumina/YAG 20 vol% composite by co-precipitation

    Directory of Open Access Journals (Sweden)

    Radosław Lach

    2011-12-01

    Full Text Available Co-precipitation of alumina/YAG precursor from aluminum and yttrium nitrate solution with ammonium carbonate results in dawsonite. Its crystallographic parameters differ from the compound precipitated with no yttrium additive. It suggests that yttrium ions become incorporated into the dawsonite structure. The DSC/TG and X-ray diffraction measurements show decomposition of dawsonite at elevated temperatures resulting in γ-Al2O3 and then δ- and θ-alumina modifications. Full transformation to α-Al2O3 and YAG occurs at temperatures higher than 1230°C. Starting powder for the sintering experiments was prepared using the coprecipitated precursor calcined at 600°C. Seeding of such powder with 5 wt.% α-Al2O3 results in material of 98% density at 1500°C. Much lower densification show compacts of unseeded powder.

  4. Synthesis control and characterization of hydroxyapatite prepared by wet precipitation process

    Directory of Open Access Journals (Sweden)

    Maria Helena Santos

    2004-12-01

    Full Text Available Several techniques have been utilized for the preparation of hydroxyapatite (HA and other calcium phosphates for the development of biomaterials. It is vital to know the reaction kinetics to be able to control the material obtained by the aqueous solution route. In the present work, HA has been produced by different wet precipitation processes and different experimental conditions. Calcium hydroxide, calcium phosphate, ammonium phosphate and phosphoric acid were used as reagents. The precipitate was dried at 100 °C overnight and then some samples were treated at 900 °C for 2 h. The powder samples were characterized by scanning electron microscopy (SEM, X-ray fluorescence (XRF and X-ray diffraction (XRD analyses. SEM photomicrographs showed an aggregate powder, granular to dense and suggested typical columnar particles. Qualitative XRF showed that the main components of HA powders were calcium and phosphorus. Pure HA and other phases according to processing parameters were observed by XRD analysis.

  5. Antimicrobial Polyethylene through Melt Compounding with Quaternary Ammonium Salts

    Directory of Open Access Journals (Sweden)

    Fernanda F. Rossetti

    2017-01-01

    Full Text Available Selected mono- and bicationic quats were compounded with polyethylene. The physicochemical surface properties, leaching behavior, and antibacterial activity of such modified samples were investigated. Contact angle measurements and fluorescein binding assays showed the presence of quaternary ammonium groups at the surface. After storing the samples in 50°C warm water for 30 days, several were still antimicrobially active. No correlation between the number of exposed N+ head groups after leaching and the antibacterial activity was observed. There is however a qualitative correlation of the antibacterial activity with the contact angles and surface concentrations of N+ before leaching/storing in warm water.

  6. Chemistry of rare earth solvent extraction by methyltrialkyl ammonium nitrate

    International Nuclear Information System (INIS)

    Stepanov, S.I.; Tulina, L.V.; Stratonov, A.V.

    1989-01-01

    Solvent extaction of nitrates of lanthanum, gadolinium, dysprosium and erbium by methyltrialkyl ammonium nitrate is studied. Usng the methods of saturation and physicochemical analysis of extraction systems it is shown that along with di-and trisolvates, solvates containing 6,4,21/2 and 11/2 molecules of extractant per a molecule of lanthanide nitrate, are formed, depending on the lanthanide atomic number. The thermodynamic constants of extraction for every determined solvate are calculated and tabulated. 10 refs.; 2 figs.; 1 tab

  7. Ammonium Bifluoride Poisoning: Our Eight-year Experiences

    OpenAIRE

    Serkan Özsoylu; Başak Akyıldız; Adem Dursun

    2018-01-01

    Introduction: The aim of the study was to discuss clinical effects, treatment options and outcomes of pediatric ammonium bifluoride (ABF) poisoning. Methods: This study was designed as retrospective case series. We analyzed the medical records of children who were hospitalized for ABF poisoning between January 2009 and October 2017. Results: The median calcium level on arrival to the hospital was 9.26 mg/dL (minimum-maximum: 4.6-10.9). The median calcium level 2 hours after arrival was ...

  8. Bifunctional ammonium compounds as promising extragents of metals

    International Nuclear Information System (INIS)

    Rakhman'ko, E.M.; Polishchuk, S.V.; Tsvirko, G.A.; Starobinets, G.L.; Leshchev, S.M.

    1988-01-01

    Salts of dinonyl-aminoethyl-β-trinonylammonium (DNAE-β-TNA) and methylpentadecylethylenediammonium (MPDEDA) have been synthesized and studied as extractions. Extraction of CdBr 2 and CdI 2 by MPDEDA picrate in toluene and their binary mixture with chloroform, amyl-acetate and octane is investigated. It is shown that Cd is extracted by quaternary ammonium salt in the form of complex anion CdX 4 2- , where X-Br, I. The mechanism and extraction process kinetics are described. Molecular structure of the complexes formed is presented. 2 refs.; 2 figs.; 2 tabs

  9. Subsurface ammonium maxima in northern Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Satyanarayana, D.; Sahu, S.D.; Panigrahy, P.K.; Sarma, V.V.; Suguna, C.

    in the Arabian sea. Deep-sea Res., 29A, 459-69. Okuda, T., Ruiz, J. B. & Garcia, A. J. (1974). Algunas characteristics bioquimicas en el agua de la Fosa de Cariaco. Boletin del Institute Oceanografico de la Universidad de oriente, 13, 163-74. Olson, R. J... in the euphotic zone may be due to the combined effects of particle sinking, uptake by phytoplankton and regeneration by zooplankton. Even though ammonium is the preferred nitrogen source for uptake by phytoplankton (McCarthy et aL, 1977; Eppley el al., 1979...

  10. The Properties of Ammonium Dinitramine (ADN): Part 2: Melt Casting

    Science.gov (United States)

    Hahma, A.; Edvinsson, H.; Östmark, H.

    2010-04-01

    A melt casting technique for ammonium dinitramine (ADN) and ADN/aluminum was developed. ADN proved relatively easy to cast, when 1% of magnesium oxide was used as a stabilizer and crystallization kernels. Densities of ADN/MgO 99/1 were 92 to 97% of theoretical mean density (TMD) and those of ADN/Al/MgO 64/35/1 were between 95 and 99% of TMD. Sedimentation of Al in the melt was prevented and the particle wetting was ensured by selecting a suitable particle size for Al. No gelling agents or other additives were used. The casting process and factors influencing it are discussed.

  11. A study on chlorination of uranium metal using ammonium chloride

    International Nuclear Information System (INIS)

    Eun, H.C.; Kim, T.J.; Jang, J.H.; Kim, G.Y.; Lee, S.J.; Hur, J.M.

    2017-01-01

    In this study, the chlorination of uranium metal using ammonium chloride (NH 4 Cl) was conducted to derive an easy and simple uranium chloride production method without impurities. In thermodynamic equilibrium calculations, it was predicted that only uranium chlorides can be produced by the reactions between uranium metal and NH 4 Cl. Experimental conditions for the chlorination of uranium metal were determined using a chlorination test of cerium metal using NH 4 Cl. It was confirmed that UCl 3 and UCl 4 in the form of particles as uranium chlorination products can be obtained from the chlorination method using NH 4 Cl. (author)

  12. Rosin (colophony) holograms sensitized with ammonium dichromate ®

    Science.gov (United States)

    Olivares-Pérez, A.; Ibarra-Torres, J. C.; Ortiz-Gutiérrez, M.; Pérez-Cortés, M.; Fuentes-Tapia, I.

    2005-12-01

    We report a photosensitive emulsion by mixing ammonium dichromate with rosin resin diluted in isopropyl alcohol. This material can be easily elaborated. A phase grating in this material was recorded using an argon-ion laser at λ = 457 nm, shows a moderate diffraction efficiency. This material is capable of a high resolution when we record some diffraction gratings, observing the order of 2000 l/mm (grooves). A characteristic of the developed process is its simplicity that it takes approximately 25 s. It describes a hypothesis with respect to some mechanisms of photosensitivity in emulsions.

  13. Characteristic features of winter precipitation and its variability over ...

    Indian Academy of Sciences (India)

    Keywords. Northwest India; winter precipitation; western disturbances; rabi crops; precipitation variability; precipitation epochs. ... The precipitation is mainly associated with the sequence of synoptic systems known as 'western disturbances'. The precipitation has ... National Atmospheric Research Laboratory, Tirupati, India.

  14. Molecular recognition of organic ammonium ions in solution using synthetic receptors

    Directory of Open Access Journals (Sweden)

    Andreas Späth

    2010-04-01

    Full Text Available Ammonium ions are ubiquitous in chemistry and molecular biology. Considerable efforts have been undertaken to develop synthetic receptors for their selective molecular recognition. The type of host compounds for organic ammonium ion binding span a wide range from crown ethers to calixarenes to metal complexes. Typical intermolecular interactions are hydrogen bonds, electrostatic and cation–π interactions, hydrophobic interactions or reversible covalent bond formation. In this review we discuss the different classes of synthetic receptors for organic ammonium ion recognition and illustrate the scope and limitations of each class with selected examples from the recent literature. The molecular recognition of ammonium ions in amino acids is included and the enantioselective binding of chiral ammonium ions by synthetic receptors is also covered. In our conclusion we compare the strengths and weaknesses of the different types of ammonium ion receptors which may help to select the best approach for specific applications.

  15. CONCENTRATION OF Pu USING AN IODATE PRECIPITATE

    Science.gov (United States)

    Fries, B.A.

    1960-02-23

    A method is given for separating plutonium from lanthanum in a lanthanum fluoride carrier precipitation process for the recovery of plutonium values from an aqueous solution. The carrier precipitation process includes the steps of forming a lanthanum fluoride precipi- . tate, thereby carrying plutonium out of solution, metathesizing the fluoride precipitate to a hydroxide precipitate, and then dissolving the hydroxide precipitate in nitric acid. In accordance with the invention, the nitric acid solution, which contains plutonium and lanthanum, is made 0.05 to 0.15 molar in potassium iodate. thereby precipitating plutonium as plutonous iodate and the plutonous iodate is separated from the lanthanum- containing supernatant solution.

  16. A Novel Eco-Friendly Vanadium Precipitation Method by Hydrothermal Hydrogen Reduction Technology

    Directory of Open Access Journals (Sweden)

    Guobin Zhang

    2017-09-01

    Full Text Available In view of the serious pollution problems caused by the traditional vanadium precipitation process, the eco-friendly technology of hydrothermal hydrogen reduction was first applied to precipitate phase pure vanadium sesquioxide (V2O3 products from stripped pentavalent vanadium (V (V solution extracted from vanadium-bearing shale. Thermodynamic analysis demonstrate the method of hydrothermal hydrogen reduction is feasible for precipitating V2O3 from V (V solution at a suitable pH range, and the reduction should better be carried out at a lower pH under the pH range in which V2O3 can exist stably. The V2O3 products of 99.92% in purity and a high vanadium precipitation percentage of 99.25% were achieved under a facile reaction condition of initial solution pH of 6, reaction temperature of 523 K, H2 partial pressure of 4 MPa and reaction time of 2 h. Based on the analysis of XRD and FE-SEM with EDS for the precipitation products obtained at serial reaction times, the phase transformation mechanism was summarized to serial reductions with the phase transformation of HxVyOz(2z−x−5y− → NaV2O5 → VO2(H2O0.5 → VOOH → V2O3. Compared with the two-step traditional method of precipitating vanadium with ammonium salt and roast-reduction (react at above 773 K for more than 3 h for preparing V2O3, this method only experiences one-step reduction under a green atmosphere of H2 gas with a lower reaction temperature of 523 K and a shorter reaction time of 2h. Therefore, this method for vanadium precipitation is characterized by being eco-friendly, having a short process and being low-energy consumption, which has great significance for the sustainable development of vanadium industry.

  17. An Integrated Chemical Reactor-Heat Exchanger Based on Ammonium Carbamate (POSTPRINT)

    Science.gov (United States)

    2012-10-01

    AFRL-RQ-WP-TP-2013-0237 AN INTEGRATED CHEMICAL REACTOR-HEAT EXCHANGER BASED ON AMMONIUM CARBAMATE (POSTPRINT) Douglas Johnson and Jamie...4. TITLE AND SUBTITLE AN INTEGRATED CHEMICAL REACTOR-HEAT EXCHANGER BASED ON AMMONIUM CARBAMATE (POSTPRINT) 5a. CONTRACT NUMBER In-house 5b...Ammonium carbamate (AC) which has a decomposition enthalpy of 1.8 MJ/kg is suspended in propylene glycol and used as the heat exchanger working fluid

  18. Ammonium removal from municipal wastewater with application of ion exchange and partial nitritation/Anammox process

    OpenAIRE

    Malovanyy, Andriy

    2014-01-01

    Nitrogen removal from municipal wastewater with application of Anammox process offers cost reduction, especially if it is combined with maximal use of organic content of wastewater for biogas production. In this study a new technology is proposed, which is based on ammonium concentration from municipal wastewater by ion exchange followed by biological removal of ammonium from the concentrated stream by partial nitritation/Anammox process. In experiments on ammonium concentration four the most...

  19. Ammonium sulfate and MALDI in-source decay: a winning combination for sequencing peptides

    OpenAIRE

    Delvolve, Alice; Woods, Amina S.

    2009-01-01

    In previous papers we highlighted the role of ammonium sulfate in increasing peptide fragmentation by in source decay (ISD). The current work systematically investigated effects of MALDI extraction delay, peptide amino acid composition, matrix and ammonium sulfate concentration on peptides ISD fragmentation. The data confirmed that ammonium sulfate increased peptides signal to noise ratio as well as their in source fragmentation resulting in complete sequence coverage regardless of the amino ...

  20. Copolymerization of poly (ethylene oxide) and poly (methyl methacrylate) initiated by ceric ammonium nitrate

    International Nuclear Information System (INIS)

    Gomes, A.S.; Ferreira, A.A.; Coutinho, F.M.B.; Marinho, J.R.D.

    1984-01-01

    Cerium (IV) salts such as the ceric ammonium nitrate and ceric ammonium sulfate in aqueous acid solution with reducing agents such as alcohols, thiols, glycols, aldehydes and amines are well known initiators of vinyl polymerization. In this work, the polymerization of methyl methacrylate initiated by ceric ammonium nitrate/HNO 3 -poly(ethylene oxide) with hydroxyl end group system was studied in aqueous solution at 25 0 C to obtain block copolymers. (Author) [pt

  1. Lanthanum aluminate synthesis by reverse precipitation starting from pseudoboehmite; Sintesis de aluminato de lantano mediante precipitacion inversa partiendo de pseudoboehmita

    Energy Technology Data Exchange (ETDEWEB)

    Portilla Z, K. G.; Zarate M, J.; Tapia O, J. P.; Hernandez M, W., E-mail: whernandezmu@gmail.com [Universidad Michoacana de San Nicolas de Hidalgo, Instituto de Investigacion en Metalurgia y Materiales, Ciudad Universitaria, Edif. U, 58060 Morelia (Mexico)

    2015-10-15

    Full text: The lanthanum aluminate (Lao) shows a thermoluminescence response thus has been proposed as a material for dosimetry; this has made have been proposed various methods for their synthesis (hydrothermal, sol-gel, combustion, precipitation, etc.) These methods are complex or expensive if part of reagent grade materials which limits its application to larger scales. Therefore is proposed to use the pseudoboehmite as a precursor of alumina for the Lao phase. Pseudoboehmite was synthesized by reverse precipitation starting from aluminum sulfate and as precipitating agent the ammonium hydroxide. Lao perovskite phase was obtained at 1500 degrees C and 10 h of calcination s, at lower temperatures the presence of other phases as lanthanum oxide was detected. Also the morphology of the powders were characterized by scanning electron microscopy, finding clusters whose sizes are in the range of ∼0.25 and 1 μm. The measurement of the density by the Archimedes method reached 94% of the theoretical. (Author)

  2. Precipitation patterns during channel flow

    Science.gov (United States)

    Jamtveit, B.; Hawkins, C.; Benning, L. G.; Meier, D.; Hammer, O.; Angheluta, L.

    2013-12-01

    Mineral precipitation during channelized fluid flow is widespread in a wide variety of geological systems. It is also a common and costly phenomenon in many industrial processes that involve fluid flow in pipelines. It is often referred to as scale formation and encountered in a large number of industries, including paper production, chemical manufacturing, cement operations, food processing, as well as non-renewable (i.e. oil and gas) and renewable (i.e. geothermal) energy production. We have studied the incipient stages of growth of amorphous silica on steel plates emplaced into the central areas of the ca. 1 meter in diameter sized pipelines used at the hydrothermal power plant at Hellisheidi, Iceland (with a capacity of ca 300 MW electricity and 100 MW hot water). Silica precipitation takes place over a period of ca. 2 months at approximately 120°C and a flow rate around 1 m/s. The growth produces asymmetric ca. 1mm high dendritic structures ';leaning' towards the incoming fluid flow. A novel phase-field model combined with the lattice Boltzmann method is introduced to study how the growth morphologies vary under different hydrodynamic conditions, including non-laminar systems with turbulent mixing. The model accurately predicts the observed morphologies and is directly relevant for understanding the more general problem of precipitation influenced by turbulent mixing during flow in channels with rough walls and even for porous flow. Reference: Hawkins, C., Angheluta, L., Hammer, Ø., and Jamtveit, B., Precipitation dendrites in channel flow. Europhysics Letters, 102, 54001

  3. Precipitation processes in implanted materials

    International Nuclear Information System (INIS)

    Borders, J.A.

    1978-01-01

    Ion implantation is a nonequilibrium process. It is possible to implant materials with impurities to concentration levels which exceed the solid solubilities. The return of the system to thermodynamic equilibrium is often accomplished by precipitation of the implanted species or a compound involving atoms of both the host and the implanted species. This may involve long time scales when taking place at room temperature or it may take place during the implantation

  4. Antibiotics with anaerobic ammonium oxidation in urban wastewater treatment

    Science.gov (United States)

    Zhou, Ruipeng; Yang, Yuanming

    2017-05-01

    Biofilter process is based on biological oxidation process on the introduction of fast water filter design ideas generated by an integrated filtration, adsorption and biological role of aerobic wastewater treatment process various purification processes. By engineering example, we show that the process is an ideal sewage and industrial wastewater treatment process of low concentration. Anaerobic ammonia oxidation process because of its advantage of the high efficiency and low consumption, wastewater biological denitrification field has broad application prospects. The process in practical wastewater treatment at home and abroad has become a hot spot. In this paper, anammox bacteria habitats and species diversity, and anaerobic ammonium oxidation process in the form of diversity, and one and split the process operating conditions are compared, focusing on a review of the anammox process technology various types of wastewater laboratory research and engineering applications, including general water quality and pressure filtrate sludge digestion, landfill leachate, aquaculture wastewater, monosodium glutamate wastewater, wastewater, sewage, fecal sewage, waste water salinity wastewater characteristics, research progress and application of the obstacles. Finally, we summarize the anaerobic ammonium oxidation process potential problems during the processing of the actual waste water, and proposed future research focus on in-depth study of water quality anammox obstacle factor and its regulatory policy, and vigorously develop on this basis, and combined process optimization.

  5. High-pressure structural study of Ammonium Perchlorate

    Science.gov (United States)

    Stavrou, Elissaios; Zaug, Joseph; Bastea, Sorin; Grivickas, Paulius; Greenberg, Eran; Kunz, Martin

    Ammonium perchlorate (AP) with the chemical formula NH4ClO4 is a powerful energetic oxidizer used as an ingredient in rocket propellants and explosive formulations. For this reason, its structural properties under extreme conditions have attracted considerable attention (M. Dunuwille et al., S. Hunter et al.). However, its structural properties under pressure are not completely understood. In addition to its importance as an energetic oxidizer, AP is one of the simplest supramolecular systems. Thus, a structural study of AP under pressure can provide crucial information in the context of the emerging field of high pressure supramolecular chemistry. Ammonium perchlorate has been studied using x-ray diffraction and Raman spectroscopy up to the record pressure of 40 GPa. The results reveal a pressure-induced first order phase transition at 4 GPa, in agreement with previous studies. However, preliminary analysis of our results contradicts with the previously proposed high-pressure phase, as determined by neutron diffraction. No further structural phase transitions have been observed up to the highest pressure of this study. Intermolecular bonding between NH4 and ClO4 ions will be discussed based on Raman spectroscopy measurements. This work was performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Security, LLC under Contract DE-AC52-07NA27344.

  6. Shock Initiation and Equation of State of Ammonium Nitrate

    Science.gov (United States)

    Robbins, David; Sheffield, Steve; Dattelbaum, Dana; Chellappa, Raja; Velisavljevic, Nenad

    2013-06-01

    Ammonium nitrate (AN) is a widely used fertilizer and mining explosive commonly found in ammonium nitrate-fuel oil. Neat AN is a non-ideal explosive with measured detonation velocities approaching 4 km/s. Previously, we reported a thermodynamically-complete equation of state for AN based on its maximum density, and showed that near-full density AN did not initiate when subjected to shock input conditions up to 22 GPa. In this work, we extend these initial results, by presenting new Hugoniot data for intermediate density neat AN obtained from gas gun-driven plate impact experiments. AN at densities from 1.8 to 1.5 g/cm3 were impacted into LiF windows using a two-stage light gas gun. Dual VISARs were used to measure the interfacial particle velocity wave profile as a function of time following impact. The new Hugoniot data, in addition to updates to thermodynamic parameters derived from structural analysis and vibrational spectroscopy measurements in high pressure diamond anvil cell experiments, are used to refine the unreacted EOS for AN. Furthermore, shock initiation of neat AN was observed as the initial porosity increased (density decreased). Insights into the relationship(s) between initial density and shock initiation sensitivity are also presented, from evidence of shock initiation in the particle velocity profiles obtained for the lower density AN samples.

  7. High performance spiro ammonium electrolyte for Electric Double Layer Capacitors

    Science.gov (United States)

    DeRosa, Donald; Higashiya, Seiichiro; Schulz, Adam; Rane-Fondacaro, Manisha; Haldar, Pradeep

    2017-08-01

    The smallest spiro ammonium salt reported to date, 1 M 4-Axoniaspiro[3,4]octane tetrafluoroborate (APBF4), was successfully synthesized and investigated as the electrolyte with acetonitrile (AN) in an Electric Double Layer Capacitor (EDLC) for the first time. The electrochemical characteristics of EDLC devices containing 1 M APBF4/AN paired with commercial activated carbon electrodes were compared to devices containing popular EDLC electrolytes, 1 M 5-Azoniaspiro[4.4]nonane tetrafluoroborate (SBPBF4/AN) and 1 M tetraethyl ammonium tetrafluoroborate (TEABF4/AN), using cyclic voltammetry (CV), galvanostatic charge discharge (GCD), and electrochemical impedance spectroscopy (EIS). The average gravimetric capacitance of the 1 M APBF4 device (124.7 F g-1) was found to be greater than the values measured for both the 1 M SBPBF4 device (108.6 F g-1) and the 1 M TEABF4 device (99.2 F g-1). The direct current equivalent series resistance (ESR) of the 1 M APBF4 device (383.4 mΩ cm-2) was found to be substantially lower than the values measured for both the 1 M SBPBF4 device (501.0 mΩ cm-2) and the 1 M TEABF4 device (710.8 mΩ cm-2). These results demonstrate that APBF4, when compared to current commercial electrolytes, significantly enhances the energy storage properties of EDLC devices.

  8. Ammonium-tungstate-promoted growth of boron nitride nanotubes

    Science.gov (United States)

    E, Songfeng; Li, Chaowei; Li, Taotao; Geng, Renjie; Li, Qiulong; Lu, Weibang; Yao, Yagang

    2018-05-01

    Ammonium tungstate ((NH4)10W12O41 · xH2O) is a kind of oxygen-containing ammonium salt. The following study proves that it can be successfully used as a metal oxide alternative to produce boron oxide (B2O2) by oxidizing boron (B) in a traditional boron oxide chemical vapor deposition (BOCVD) process. This special oxidant promotes the simplistic fabrication of boron nitride nanotubes (BNNTs) in a conventional horizontal tube furnace, an outcome which may have resulted from its strong oxidizability. The experimental results demonstrate that the mole ratio of B and (NH4)10W12O41 · xH2O is a key parameter in determining the formation, quality and quantity of BNNTs when stainless steel is employed as a catalyst. We also found that Mg(NO3)2 and MgO nanoparticles (NPs) can be used as catalysts to grow BNNTs with the same precursor. The BNNTs obtained from the Mg(NO3)2 catalyst were straighter than those obtained from the MgO NP catalyst. This could have been due to the different physical forms of the catalysts that were used.

  9. Efficient ozone, sulfate, and ammonium free resist stripping process

    Science.gov (United States)

    Dattilo, Davide; Dietze, Uwe

    2014-07-01

    In recent years, photomask resist strip and cleaning technology development was substantially driven by the industry's need to prevent surface haze formation through the elimination of sulfuric acid and ammonium hydroxide from these processes. As a result, conventional SPM (H2SO4 + H2O2) was replaced with Ozone water (DIO3) for resist stripping and organic removal to eliminate chemical haze formation [1, 2]. However, it has been shown that DIO3 basted strip and clean process causes oxidative degradation of photomask materials [3, 4]. Such material damage can affect optical properties of funcitional mask layers, causeing CD line-width, phase, transmission and reflection changes, adversely affecting image transfer during the Lithography process. To overcome Ozone induced surface damage, SUSS MicroTec successfully developed a highly efficient strip process, where photolysis of DIO3 is leading to highly reactive hydroxyl radical formation, as the main contribution to hydrocarbon removal without surface damage [5]. This technology has been further extended to a final clean process, which is utilizing pure DI water for residual organic material removal during final clean [6]. Recently, SUS MicroTec did also successfully release strip and clean processes which completely remove NH4OH, eliminating any chemicals known today to induce haze [7]. In this paper we show the benefits of these new technologies for highly efficient sulfate and ammonium free stripping and cleaning processes.

  10. Ambient and laboratory observations of organic ammonium salts in PM1.

    Science.gov (United States)

    Schlag, P; Rubach, F; Mentel, T F; Reimer, D; Canonaco, F; Henzing, J S; Moerman, M; Otjes, R; Prévôt, A S H; Rohrer, F; Rosati, B; Tillmann, R; Weingartner, E; Kiendler-Scharr, A

    2017-08-24

    Ambient measurements of PM 1 aerosol chemical composition at Cabauw, the Netherlands, implicate higher ammonium concentrations than explained by the formation of inorganic ammonium salts. This additional particulate ammonium is called excess ammonium (e NH 4 ). Height profiles over the Cabauw Experimental Site for Atmospheric Research (CESAR) tower, of combined ground based and airborne aerosol mass spectrometric (AMS) measurements on a Zeppelin airship show higher concentrations of e NH 4 at higher altitudes compared to the ground. Through flights across the Netherlands, the Zeppelin based measurements furthermore substantiate e NH 4 as a regional phenomenon in the planetary boundary layer. The excess ammonium correlates with mass spectral signatures of (di-)carboxylic acids, making a heterogeneous acid-base reaction the likely process of NH 3 uptake. We show that this excess ammonium was neutralized by the organic fraction forming particulate organic ammonium salts. We discuss the significance of such organic ammonium salts for atmospheric aerosols and suggest that NH 3 emission control will have benefits for particulate matter control beyond the reduction of inorganic ammonium salts.

  11. The importance of ammonium mobility in nitrogen-impacted unfertilized grasslands: A critical reassessment

    International Nuclear Information System (INIS)

    Mian, Ishaq Ahmad; Riaz, Muhammad; Cresser, Malcolm S.

    2009-01-01

    The physico-chemical absorption characteristics of ammonium-N for 10 soils from 5 profiles in York, UK, show its high potential mobility in N deposition-impacted, unfertilized, permanent grassland soils. Substantial proportions of ammonium-N inputs were retained in the solution phase, indicating that ammonium translocation plays an important role in the N cycling in, and losses from, such soils. This conclusion was further supported by measuring the ammonium-N leaching from intact plant/soil microcosms. The ammonium-N absorption characteristics apparently varied with soil pH, depth and soil texture. It was concluded for the most acid soils especially that ammonium-N leached from litter horizons could be seriously limiting the capacity of underlying soils to retain ammonium. Contrary to common opinion, more attention therefore needs to be paid to ammonium leaching and its potential role in biogeochemical N cycling in semi-natural soil systems subject to atmospheric pollution. - Ammonium mobility is more important than previously thought in N-impacted, unfertilized grasslands

  12. Phosphate limitation in biological rapid sand filters used to remove ammonium from drinking water

    DEFF Research Database (Denmark)

    Lee, Carson Odell; Albrechtsen, Hans-Jørgen; Smets, Barth F.

    2013-01-01

    Removing ammonium from drinking water is important for maintaining biological stability in distribution systems. This is especially important in regions that do not use disinfectants in the treatment process or keep a disinfectant residual in the distribution system. Problems with nitrification can...... occur with increased ammonium loads caused by seasonal or operational changes and can lead to extensive periods of elevated ammonium and nitrite concentrations in the effluent. One possible cause of nitrification problems in these filters maybe due to phosphate limitation. This was investigated using...... the total number of ammonium oxidizing bacteria in the column. © 2013 American Water Works Association AWWA WQTC Conference Proceedings All Rights Reserved....

  13. Characterization of tomato growth and fruit quality under foliar ammonium sprays

    OpenAIRE

    Souri Mohammad Kazem; Dehnavard Sara

    2017-01-01

    This study was done to evaluate the effects of foliar application of ammonium sulfate on growth and fruit quality of tomato plants under hydroponic culture system. Over four months of tomato plant growth, plants were sprayed once per week with different concentrations of ammonium sulfate (0, 50, 100 and 200 mM), as well as with 50 mM every second day. Foliar application of ammonium sulfate led to reductions in many growth and quality parameters, and higher ammonium concentrations exerted grea...

  14. Urine Anion Gap to Predict Urine Ammonium and Related Outcomes in Kidney Disease.

    Science.gov (United States)

    Raphael, Kalani L; Gilligan, Sarah; Ix, Joachim H

    2018-02-07

    Low urine ammonium excretion is associated with ESRD in CKD. Few laboratories measure urine ammonium, limiting clinical application. We determined correlations between urine ammonium, the standard urine anion gap, and a modified urine anion gap that includes sulfate and phosphate and compared risks of ESRD or death between these ammonium estimates and directly measured ammonium. We measured ammonium, sodium, potassium, chloride, phosphate, and sulfate from baseline 24-hour urine collections in 1044 African-American Study of Kidney Disease and Hypertension participants. We evaluated the cross-sectional correlations between urine ammonium, the standard urine anion gap (sodium + potassium - chloride), and a modified urine anion gap that includes urine phosphate and sulfate in the calculation. Multivariable-adjusted Cox models determined the associations of the standard urine anion gap and the modified urine anion gap with the composite end point of death or ESRD; these results were compared with results using urine ammonium as the predictor of interest. The standard urine anion gap had a weak and direct correlation with urine ammonium ( r =0.18), whereas the modified urine anion gap had a modest inverse relationship with urine ammonium ( r =-0.58). Compared with the highest tertile of urine ammonium, those in the lowest urine ammonium tertile had higher risk of ESRD or death (hazard ratio, 1.46; 95% confidence interval, 1.13 to 1.87) after adjusting for demographics, GFR, proteinuria, and other confounders. In comparison, participants in the corresponding standard urine anion gap tertile did not have higher risk of ESRD or death (hazard ratio, 0.82; 95% confidence interval, 0.64 to 1.07), whereas the risk for those in the corresponding modified urine anion gap tertile (hazard ratio, 1.32; 95% confidence interval, 1.03 to 1.68) approximated that of directly measured urine ammonium. Urine anion gap is a poor surrogate of urine ammonium in CKD unless phosphate and

  15. A co-precipitation technique for the preparation of ferroelectric BaBi{sub 2}Ta{sub 2}O{sub 9}

    Energy Technology Data Exchange (ETDEWEB)

    Dhage, S.R. [Physical and Materials Chemistry Division, National Chemical Laboratory, Pune 411008 (India); Pasricha, R. [Center for Materials Characterization, National Chemical Laboratory, Pune 411008 (India); Vadivel Murugan, A. [Centre for Materials for Electronics Technology (C-MET), Department of Information Technology, Government of India, Dr. Homibhabha Road, Panchawati, Pune 411008 (India); Ravi, V. [Physical and Materials Chemistry Division, National Chemical Laboratory, Pune 411008 (India)]. E-mail: ravi@ems.ncl.res.in

    2006-08-01

    A simple co-precipitation technique had been successfully applied for the preparation of pure ultrafine single phase BaBi{sub 2}Ta{sub 2}O{sub 9} (BBT). Ammonium hydroxide and ammonium oxalate were used to precipitate Ba{sup 2+}, Bi{sup 3+} and Ta{sup 5+} cations simultaneously. No pyrochlore phase was found while heating powder at 800 deg. C and pure BaBi{sub 2}Ta{sub 2}O{sub 9} phase was found to be formed by X-ray diffraction. Particle size and morphology was studied by transmission electron spectroscopy (TEM). The room temperature dielectric constant at 1 kHz is 350. The ferroelectric hysteresis loop parameters of these samples were also studied.

  16. U.S. 15 Minute Precipitation Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — U.S. 15 Minute Precipitation Data is digital data set DSI-3260, archived at the National Climatic Data Center (NCDC). This is precipitation data. The primary source...

  17. European climate change experiments on precipitation change

    DEFF Research Database (Denmark)

    Beier, Claus

    Presentation of European activities and networks related to experiments and databases within precipitation change......Presentation of European activities and networks related to experiments and databases within precipitation change...

  18. Amazon River Basin Precipitation, 1972-1992

    Data.gov (United States)

    National Aeronautics and Space Administration — The precipitation data is 0.2 degree gridded monthly precipitation data based upon monthly rain data from Peru and Bolivia and daily rain data from Brazil. The...

  19. Amazon River Basin Precipitation, 1972-1992

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: The precipitation data is 0.2 degree gridded monthly precipitation data based upon monthly rain data from Peru and Bolivia and daily rain data from Brazil....

  20. Global Precipitation Measurement (GPM) Mission: NASA Precipitation Processing System (PPS)

    Science.gov (United States)

    Stocker, Erich Franz

    2008-01-01

    NASA is contributing the precipitation measurement data system PPS to support the GPM mission. PPS will distribute all GPM data products including NASA s GMI data products freely and quickly. PPS is implementing no system mechanisms for restricting access to GPM data. PPS is implementing no system mechanisms for charging for GPM data products. PPS will provide a number of geographical and parameter subsetting features available to its users. The first implementation of PPS (called PPS--) will assume processing of TRMM data effective 1 June 2008. TRMM realtime data will be available via PPS- to all users requesting access

  1. Composition and hygroscopicity of aerosol particles at Mt. Lu in South China: Implications for acid precipitation

    Science.gov (United States)

    Li, Weijun; Chi, Jianwei; Shi, Zongbo; Wang, Xinfeng; Chen, Bin; Wang, Yan; Li, Tao; Chen, Jianmin; Zhang, Daizhou; Wang, Zifa; Shi, Chune; Liu, Liangke; Wang, Wenxing

    2014-09-01

    Physicochemical properties of aerosol particles were studied at Mt. Lu, an elevated site (115°59‧E, 29°35‧N, 1165 m) within the acid precipitation area. Northeast winds transport copious amounts of air pollutants and water vapor from the Yangtze River Delta into this acid precipitation area. NH4+ and SO42- are the dominant ions in PM2.5 and determine aerosol acidity. Individual particle analysis shows abundant S-rich and metals (i.e. Fe-, Zn-, Mn-, and Pb-rich) particles. Unlike aerosol particles in North China and urban areas, there are little soot and mineral particles at Mt. Lu. Lack of mineral particles contributed to the higher acidity in precipitation in the research area. Nano-sized spherical metal particles were observed to be embedded in 37% of S-rich particles. These metal particles were likely originated from heavy industries and fired-power plants. Hygroscopic experiments show that most particles start to deliquesce at 73-76% but organic coating lowers the particle deliquescence relative humidity (DRH) to 63-73%. The DRHs of these aerosol particles are clearly smaller than that of pure ammonium sulfate particles which is 80%. Since RH in ambient air was relatively high, ranging from 65% to 85% during our study period, most particles at our sampling site were in liquid phase. Our results suggest that liquid phase reactions in aerosol particles may contribute to SO2 to sulfuric acid conversion in the acid precipitation area.

  2. Ammonium sulphate on maize crops under no tillage

    Directory of Open Access Journals (Sweden)

    Maria Anita Gonçalves da Silva

    2012-01-01

    Full Text Available The objectives of this work were to evaluate the management of N and S (as ammonium sulphate fertilization under no-tillage system on the components of maize productivity and on N and S accumulation in the crop, as well as to evaluate the minimum value of the Nitrogen Sufficiency Index (NSI 0.95 as an indicator for side dressing requirements. The experiment had a completely randomized block design with six treatments and four replications carried out in Red Latosol dystrophic soil (Hapludox, in Campo Mourão, Paraná State, where the following treatments in summer growth maize were applied: T1- 120 kg ha-1 N in seeding; T2- 120 kg ha-1 N in side dressing; T3- 40 kg ha-1 N in seeding and 80 kg ha-1 N in side dressing; T4- 30 kg ha-1 N in seeding and 90 kg ha-1 N in side dressing, monitored by a chlorophyll meter using the Nitrogen Sufficiency Index (NSI; T5- 120 kg ha-1 N anticipated in wheat seeding; T6- without nitrogen fertilization. NSI was determined by the relationship between the leaf chlorophyll index (ICF average of T4 plants and that one in the plot fertilized with 120 kg ha-1 N at the maize seed sowing (T1. During two years, ammonium sulphate was applied to the maize crop after wheat under no tillage system. In the first year, with adequate rainfall, the maize yield was similar to the one in which the complete ammonium sulphate dose application was done in maize seeding and side dressing. The anticipated fertilization to wheat seed sowing resulted in maize yield without difference from the parceled form. In the second year, with irregular rainfall, all treatments with N were similar and they increased maize yield compared to that without N fertilization. NSI of 0.95 was not efficient to evaluate maize N requirements in side dressing, and resulted in lower maize yield. N was accumulated mainly in the grains unlike S that accumulated in the plant shoots; both were highly correlated to maize productivity.

  3. Differential Expression of Aspergillus nidulans Ammonium Permease Genes Is Regulated by GATA Transcription Factor AreA

    OpenAIRE

    Monahan, Brendon J.; Askin, Marion C.; Hynes, Michael J.; Davis, Meryl A.

    2006-01-01

    The movement of ammonium across biological membranes is mediated in both prokaryotes and eukaryotes by ammonium transport proteins (AMT/MEP) that constitute a family of related sequences. We have previously identified two ammonium permeases in Aspergillus nidulans, encoded by the meaA and mepA genes. Here we show that meaA is expressed in the presence of ammonium, consistent with the function of MeaA as the main ammonium transporter required for optimal growth on ammonium as a nitrogen source...

  4. Effective assimilation of global precipitation: simulation experiments

    Directory of Open Access Journals (Sweden)

    Guo-Yuan Lien

    2013-07-01

    Full Text Available Past attempts to assimilate precipitation by nudging or variational methods have succeeded in forcing the model precipitation to be close to the observed values. However, the model forecasts tend to lose their additional skill after a few forecast hours. In this study, a local ensemble transform Kalman filter (LETKF is used to effectively assimilate precipitation by allowing ensemble members with better precipitation to receive higher weights in the analysis. In addition, two other changes in the precipitation assimilation process are found to alleviate the problems related to the non-Gaussianity of the precipitation variable: (a transform the precipitation variable into a Gaussian distribution based on its climatological distribution (an approach that could also be used in the assimilation of other non-Gaussian observations and (b only assimilate precipitation at the location where at least some ensemble members have precipitation. Unlike many current approaches, both positive and zero rain observations are assimilated effectively. Observing system simulation experiments (OSSEs are conducted using the Simplified Parametrisations, primitivE-Equation DYnamics (SPEEDY model, a simplified but realistic general circulation model. When uniformly and globally distributed observations of precipitation are assimilated in addition to rawinsonde observations, both the analyses and the medium-range forecasts of all model variables, including precipitation, are significantly improved as compared to only assimilating rawinsonde observations. The effect of precipitation assimilation on the analyses is retained on the medium-range forecasts and is larger in the Southern Hemisphere (SH than that in the Northern Hemisphere (NH because the NH analyses are already made more accurate by the denser rawinsonde stations. These improvements are much reduced when only the moisture field is modified by the precipitation observations. Both the Gaussian transformation and

  5. Skill assessment of precipitation nowcasting in Mediterranean Heavy Precipitation Events

    Science.gov (United States)

    Bech, Joan; Berenguer, Marc

    2013-04-01

    Very short-term precipitation forecasting (i.e nowcasting) systems may provide valuable support in the weather surveillance process as they allow to issue automated early warnings for heavy precipitation events (HPE) as reviewed recently by Pierce et al. (2012). The need for warnings is essential in densely populated regions of small catchments, such as those typically found in Mediterranean coastal areas, prone to flash-floods. Several HPEs that occurred in NE Spain are analyzed using a nowcasting system based on the extrapolation of rainfall fields observed with weather radar following a Lagrangian approach developed and tested successfully in previous studies (Berenguer et al. 2005, 2011). Radar-based nowcasts, with lead times up to 3 h, are verified here against quality-controlled weather radar quantitative precipitation estimates and also against a dense network of raingauges. The basic questions studied are the dependence of forecast quality with lead time and rainfall amounts in several high-impact HPEs such as the 7 September 2005 Llobregat Delta river tornado outbreak (Bech et al. 2007) or the 2 November 2008 supercell tornadic thunderstorms (Bech et al. 2011) - both cases had intense rainfall rates (30' amounts exceeding 38.2 and 12.3 mm respectively) and daily values above 100 mm. Verification scores indicated that forecasts of 30' precipitation amounts provided useful guidance for lead times up to 60' for moderate intensities (up to 1 mm in 30') and up to 2.5h for lower rates (above 0.1 mm). On the other hand correlations of radar estimates and forecasts exceeded Eulerian persistence of precipitation estimates for lead times of 1.5 h for moderate intensities (up to 0.8 mm/h). We complete the analysis with a discussion on the reliability of threshold to lead time dependence based on the event-to-event variability found. This work has been done in the framework of the ProFEWS project (CGL2010-15892). References Bech J, N Pineda, T Rigo, M Aran, J Amaro, M

  6. Importance of including ammonium sulfate ((NH42SO4 aerosols for ice cloud parameterization in GCMs

    Directory of Open Access Journals (Sweden)

    R. Yang

    2010-02-01

    Full Text Available A common deficiency of many cloud-physics parameterizations including the NASA's microphysics of clouds with aerosol-cloud interactions (hereafter called McRAS-AC is that they simulate lesser (larger than the observed ice cloud particle number (size. A single column model (SCM of McRAS-AC physics of the GEOS4 Global Circulation Model (GCM together with an adiabatic parcel model (APM for ice-cloud nucleation (IN of aerosols were used to systematically examine the influence of introducing ammonium sulfate (NH42SO4 aerosols in McRAS-AC and its influence on the optical properties of both liquid and ice clouds. First an (NH42SO4 parameterization was included in the APM to assess its effect on clouds vis-à-vis that of the other aerosols. Subsequently, several evaluation tests were conducted over the ARM Southern Great Plain (SGP and thirteen other locations (sorted into pristine and polluted conditions distributed over marine and continental sites with the SCM. The statistics of the simulated cloud climatology were evaluated against the available ground and satellite data. The results showed that inclusion of (NH42SO4 into McRAS-AC of the SCM made a remarkable improvement in the simulated effective radius of ice cloud particulates. However, the corresponding ice-cloud optical thickness increased even more than the observed. This can be caused by lack of horizontal cloud advection not performed in the SCM. Adjusting the other tunable parameters such as precipitation efficiency can mitigate this deficiency. Inclusion of ice cloud particle splintering invoked empirically further reduced simulation biases. Overall, these changes make a substantial improvement in simulated cloud optical properties and cloud distribution particularly over the Intertropical Convergence Zone (ITCZ in the GCM.

  7. Fate of arsenic, phosphate and ammonium plumes in a coastal aquifer affected by saltwater intrusion.

    Science.gov (United States)

    Colombani, N; Mastrocicco, M; Prommer, H; Sbarbati, C; Petitta, M

    2015-08-01

    A severe groundwater contamination with extensive plumes of arsenic, phosphate and ammonium was found in a coastal aquifer beneath a former fertilizer production plant. The implementation of an active groundwater remediation strategy, based on a comprehensive pump and treat scheme, now prevents the migration of the dissolved contaminants into the marine environment. However, due to the site's proximity to the coastline, a seawater wedge was induced by the pumping scheme. Additionally the groundwater flow and salinity patterns were also strongly affected by leakage from the site's sewer system and from a seawater-fed cooling canal. The objective of this study was to elucidate the fate of arsenic and its co-contaminants over the site's history under the complex, coupled hydrodynamic and geochemical conditions that prevail at the site. A detailed geochemical characterisation of samples from sediment cores and hydrochemical data provided valuable high-resolution information. The obtained data were used to develop various conceptual models and to constrain the development and calibration of a reactive transport model. The reactive transport simulations were performed for a sub-domain (two-dimensional transect) of an earlier developed three-dimensional flow and variable density solute transport model. The results suggest that in the upper sub-oxic zone the influx of oxygenated water promoted As attenuation via co-precipitation with Al and Fe oxides and copper hydroxides. In contrast, in the deeper aquifer zone, iron reduction, associated with the release of adsorbed As and the dissolution of As bearing phases, provided and still provides to date a persistent source for groundwater pollution. The presented monitoring and modelling approach could be broadly applied to coastal polluted sites by complex contaminant mixture containing As. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Thermophysical properties of two ammonium-based protic ionic liquids

    Science.gov (United States)

    Bhattacharjee, Arijit; Coutinho, João A. P.; Freire, Mara G.; Carvalho, Pedro J.

    2015-01-01

    Experimental data for density, viscosity, refractive index and surface tension are reported, for the first time, in the temperature range between 288.15 K and 353.15 K and at atmospheric pressure for two protic ionic liquids, namely 2-(dimethylamino)-N,N-dimethylethan-1-ammonium acetate, [N11{2(N11)}H][CH3CO2], and N-ethyl-N,N-dimethylammonium phenylacetate, [N112H][C7H7CO2]. The effect of the anion aromaticity and the cation’s aliphatic tails on the studied properties is discussed. From the measured properties temperature dependency the derived properties, such as the isobaric thermal expansion coefficient, the surface entropy and enthalpy, and the critical temperature, were estimated. PMID:26435554

  9. Antibacterial effect of composite resins containing quaternary ammonium polyethyleneimine nanoparticles

    International Nuclear Information System (INIS)

    Yudovin-Farber, Ira; Beyth, Nurit; Weiss, Ervin I.; Domb, Abraham J.

    2010-01-01

    Quaternary ammonium polyethyleneimine (QA-PEI)-based nanoparticles were synthesized by crosslinking with dibromopentane followed by N-alkylation with various alkyl halides and further N-methylation with methyl iodide. Insoluble pyridinium-type particles were prepared by suspension polymerization of 4-vinyl pyridine followed by N-alkylation with alkyl halides. Polyamine-based nanoparticles embedded in restorative composite resin at 1% w/w were tested for antibacterial activity against Streptococcus mutans using direct contact test. Activity analysis revealed that the alkyl chain length of the QA-PEI nanoparticles plays a significant role in antibacterial activity of the reagent. The most potent compound was octyl-alkylated QA-PEI embedded in restorative composite resin at 1% w/w that totally inhibited S. mutans growth in 3-month-aged samples. This data indicates that restorative composite resin with antibacterial properties can be produced by the incorporation of QA-PEI nanoparticles.

  10. Antibacterial effect of composite resins containing quaternary ammonium polyethyleneimine nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Yudovin-Farber, Ira [Hebrew University of Jerusalem, Department of Medicinal Chemistry and Natural Products, School of Pharmacy, Faculty of Medicine (Israel); Beyth, Nurit; Weiss, Ervin I. [Hebrew University of Jerusalem, Department of Prosthodontics, Faculty of Dentistry (Israel); Domb, Abraham J., E-mail: avid@ekmd.huji.ac.i [Hebrew University of Jerusalem, Department of Medicinal Chemistry and Natural Products, School of Pharmacy, Faculty of Medicine (Israel)

    2010-02-15

    Quaternary ammonium polyethyleneimine (QA-PEI)-based nanoparticles were synthesized by crosslinking with dibromopentane followed by N-alkylation with various alkyl halides and further N-methylation with methyl iodide. Insoluble pyridinium-type particles were prepared by suspension polymerization of 4-vinyl pyridine followed by N-alkylation with alkyl halides. Polyamine-based nanoparticles embedded in restorative composite resin at 1% w/w were tested for antibacterial activity against Streptococcus mutans using direct contact test. Activity analysis revealed that the alkyl chain length of the QA-PEI nanoparticles plays a significant role in antibacterial activity of the reagent. The most potent compound was octyl-alkylated QA-PEI embedded in restorative composite resin at 1% w/w that totally inhibited S. mutans growth in 3-month-aged samples. This data indicates that restorative composite resin with antibacterial properties can be produced by the incorporation of QA-PEI nanoparticles.

  11. Integrated Data Collection Analysis (IDCA) Program — Ammonium Nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Sandstrom, Mary M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Brown, Geoffrey W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Preston, Daniel N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pollard, Colin J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Warner, Kirstin F. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States). Indian Head Division; Sorensen, Daniel N. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States). Indian Head Division; Remmers, Daniel L. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States). Indian Head Division; Phillips, Jason J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Shelley, Timothy J. [Bureau of Alcohol, Tobacco and Firearms, Redstone Arsenal, AL (United States); Reyes, Jose A. [Applied Research Associates, Tyndall AFB, FL (United States); Hsu, Peter C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Reynolds, John G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2013-05-17

    The Integrated Data Collection Analysis (IDCA) program is conducting a proficiency study for Small- Scale Safety and Thermal (SSST) testing of homemade explosives (HMEs). Described here are the results for impact, friction, electrostatic discharge, and differential scanning calorimetry analysis of ammonium nitrate (AN). AN was tested, in most cases, as both received from manufacturer and dried/sieved. The participants found the AN to be: 1) insensitive in Type 12A impact testing (although with a wide range of values), 2) completely insensitive in BAM friction testing, 3) less sensitive than the RDX standard in ABL friction testing, 4) less sensitive than RDX in ABL ESD testing, and 5) less sensitive than RDX and PETN in DSC thermal analyses.

  12. Engineering application of anaerobic ammonium oxidation process in wastewater treatment.

    Science.gov (United States)

    Mao, Nianjia; Ren, Hongqiang; Geng, Jinju; Ding, Lili; Xu, Ke

    2017-08-01

    Anaerobic ammonium oxidation (Anammox), a promising biological nitrogen removal process, has been verified as an efficient, sustainable and cost-effective alternative to conventional nitrification and denitrification processes. To date, more than 110 full-scale anammox plants have been installed and are in operation, treating industrial NH 4 + -rich wastewater worldwide, and anammox-based technologies are flourishing. This review the current state of the art for engineering applications of the anammox process, including various anammox-based technologies, reactor selection and attempts to apply it at different wastewater plants. Process control and implementation for stable performance are discussed as well as some remaining issues concerning engineering application are exposed, including the start-up period, process disturbances, greenhouse gas emissions and especially mainstream anammox applications. Finally, further development of the anammox engineering application is proposed in this review.

  13. Non-ammonium reduced nitrogen species in atmospheric aerosol particles

    Energy Technology Data Exchange (ETDEWEB)

    Dod, R.L.; Gundel, L.A.; Benner, W.H.; Novakov, T.

    1983-08-01

    The traditional belief that ambient aerosol particles contain nitrogen predominantly in the form of inorganic ionic species such as NH/sub 4//sup +/ and NO/sub 3//sup -/ was challenged about 10 years ago by results from x-ray photoelectron spectroscopic analysis (ESCA) of California aerosol particles. A significant fraction (approx. 50%) of the reduced nitrogen was observed to have an oxidation state more reduced than ammonium, characteristic of organic nitrogen species. We have used a recently developed thermal evolved gas analysis method (NO/sub x/) in conjunction with ESCA to confirm the existence of these species in aerosol particles collected in both the United States and Europe. The agreement of EGA and ESCA analyses indicates that these species are found not only on the surface but also throughout the particles. 9 references, 6 figures.

  14. Computational Modeling of Degradation of Substituted Benzyltrimethyl Ammonium: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Long, H.; Pivovar, B. S.

    2014-09-01

    The degradation of cations on the alkaline exchange membranes is the major challenge for alkaline membrane fuel cells. In this paper, we investigated the degradation barriers by density functional theory for substituted benzyltrimethyl ammonium (BTMA+) cations, which is one of the most commonly used cations for alkaline exchange membranes. We found that substituted cations with electron-releasing substituent groups at meta-position of the benzyl ring could result in improved degradation barriers. However, after investigating more than thirty substituted BTMA+ cations with ten different substituent groups, the largest improvement of degradation barriers is only 1.6 kcal/mol. This implies that the lifetime of alkaline membrane fuel cells could increase from a few months to a few years by using substituted BTMA+ cations, an encouraging but still limited improvement for real-world applications.

  15. Effects of ammonium salts on oleaster (Elaeagnus angustifolia

    Directory of Open Access Journals (Sweden)

    Katalin Pilinszky

    2015-08-01

    Full Text Available Oleaster (Russian olive, Elaeagnus angustifolia trees are highly tolerant against a variety of abiotic stresses (water, temperature, salt, and other chemicals. Therefore, they can be used for rehabilitation of contaminated and/or low quality soils (brownfields, dump sites, wastelands, etc.. In order to study responses of oleaster to environmental stress in vivo and in vitro, we successfully sterilized and initiated its callus cultures, regenerated shoots and roots and finally whole plants from the callus. Application of ammonium (in the form of sulfate salt to the regenerated plantlets at concentrations higher than 10 mg L-1 inhibited root growth, reduced the leaf chlorophyll content and the activity of the enzyme glutamate dehydrogenase. At the same time, it induced activities of the stress marker enzyme glutathione S-transferase in the root and shoot tissues of the plant.

  16. Rotavirus gastroenteritis-associated urinary ammonium acid urate crystals.

    Science.gov (United States)

    Yokoyama, Tadafumi; Sugimoto, Naotoshi; Kato, Eiji; Ohta, Kazuhide; Ishikawa, Sayaka; Ueno, Kazuyuki; Shimizu, Masaki; Yachie, Akihiro

    2015-01-01

    Although ammonium acid urate (AAU) calculi are extremely rare renal stone components, it was recently found that many urinary tract calculi that cause post-renal renal failure in rotavirus (RV) gastroenteritis are AAU calculi. The mechanism of AAU calculi development in RV gastroenteritis has not been fully elucidated. We analyzed data from eight RV gastroenteritis patients who transiently had AAU crystals in their urinary sediment. In these patients, formation of AAU crystals occurred earlier than the formation of AAU calculi. No difference was observed in serum and urine uric acid levels between RV gastroenteritis patients with or without AAU crystals. Interestingly, fractional excretion of sodium was extremely low among patients with AAU crystals. These results suggest that the formation of AAU crystals might not be due to excretion of uric acid, but excretion of sodium. © 2015 Japan Pediatric Society.

  17. Review of Options for Ammonia/Ammonium Management

    Energy Technology Data Exchange (ETDEWEB)

    Nash, C. A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-05-06

    This report is a review of literature supporting practical ammonia/ammonium destruction processes. Melter research supporting Hanford Low Activity Waste (LAW) glass production has shown that significant amounts of ammonia will be in the melter offgas condensate. Further work with secondary waste forms indicates the potential need to remove the ammonia, perhaps by an oxidative process. This review finds likely practical chemical methods to oxidize ammonia in aqueous solution at moderate temperatures and atmospheric pressure, using easily obtained reagents. Leading candidates include nitrite oxidation to produce nitrogen gas, various peroxide oxidative processes, and air stripping. This work reviews many other processes and provides reasoning to not consider those processes further for this application.

  18. Facile synthesis of ammonium vanadate nanofibers by using reflux in aqueous V{sub 2}O{sub 5} solution with ammonium persulfate

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Se Hun [Department of Convergence Nanoscience, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Koo, Jun Mo [Department of Organic and Nano Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Oh, Seong Geun, E-mail: seongoh@hanyang.ac.kr [Department of Chemical Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Im, Seung Soon, E-mail: imss007@hanyang.ac.kr [Department of Convergence Nanoscience, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Department of Organic and Nano Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791 (Korea, Republic of)

    2017-06-15

    Ammonium vanadate nanofibers were synthesized by simple reflux method in aqueous V{sub 2}O{sub 5} solution with ammonium persulfate without relying on surfactants, catalysts, harmful solvents and autoclave. The degree of intercalation by cationic ammonium ions into the crystal structure of vanadium oxide along with its change in chemical composition were analyzed by thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IR). The morphological changes toward nanofiber structure, having diameter of 20–30 nm and a few μm length, were investigated using transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The influences of synthetic conditions, such as reaction time and concentration of sulfate (SO{sub 4}{sup 2-}), on the crystal structures and morphologies of the resulting products have investigated. As a result, the ammonium vanadate nanofiber was formed in a short reaction time through a simple reflux method and yielded comparable electrical conductivity 1.47 × 10{sup -2} S/cm. - Highlights: • Ammonium vanadate nanofiber (AVFr) was prepared by simple reflux method. • AVFr yielded comparable electrical conductivity 1.47 × 10{sup -2} S/cm. • The electrical conductivity was improved by the increased amount of ammonium ion. • Sulfate ions (SO{sub 4}{sup 2-}) play a crucial role in controlling the morphology of nanofiber.

  19. Novel carbohydrate-based chiral ammonium ionic liquids derived from isomannide

    DEFF Research Database (Denmark)

    Kumar, Vineet; Pei, Cao; Olsen, Carl E.

    2008-01-01

    This report describes the synthesis and characterization of novel carbohydrate-based chiral ammonium ionic liquids using isomannide as a biorenewable substrate. The diastereomeric interactions of these chiral ammonium ionic liquids with racemic Mosher's acid salt have been studied using NMR, which...

  20. Alkali metal and ammonium chlorides in water and heavy water (binary systems)

    CERN Document Server

    Cohen-Adad, R

    1991-01-01

    This volume surveys the data available in the literature for solid-fluid solubility equilibria plus selected solid-liquid-vapour equilibria, for binary systems containing alkali and ammonium chlorides in water or heavy water. Solubilities covered are lithium chloride, sodium chloride, potassium chloride, rubidium chloride, caesium chloride and ammonium chloride in water and heavy water.

  1. Wat is het geheim van ammonium? (interview met Bram van der Maas)

    NARCIS (Netherlands)

    Maas, van der A.A.

    2013-01-01

    Beter meten is meer weten. Dat is het uitgangspunt van de 'ion selectieve meter' die Horticoop en CleanGrow bezig zijn te ontwikkelen. Daarmee zijn zes elementen te controleren. Maar wat zegt bijvoorbeeld het gehalte ammonium over een gewas? Onderzoeker Bram van der Maas: 'Met ammonium is misschien

  2. Ammonium recovery and energy production from urine by a microbial fuel cell

    NARCIS (Netherlands)

    Kuntke, P.; Smiech, K.M.; Bruning, H.; Zeeman, G.; Saakes, M.; Sleutels, T.H.J.A.; Hamelers, H.V.M.; Buisman, C.J.N.

    2012-01-01

    Nitrogen recovery through NH3 stripping is energy intensive and requires large amounts of chemicals. Therefore, a microbial fuel cell was developed to simultaneously produce energy and recover ammonium. The applied microbial fuel cell used a gas diffusion cathode. The ammonium transport to the

  3. Global simulations of nitrate and ammonium aerosols and their radiative effects

    Directory of Open Access Journals (Sweden)

    L. Xu

    2012-10-01

    Full Text Available We examine the formation of nitrate and ammonium on five types of externally mixed pre-existing aerosols using the hybrid dynamic method in a global chemistry transport model. The model developed here predicts a similar spatial pattern of total aerosol nitrate and ammonium to that of several pioneering studies, but separates the effects of nitrate and ammonium on pure sulfate, biomass burning, fossil fuel, dust and sea salt aerosols. Nitrate and ammonium boost the scattering efficiency of sulfate and organic matter but lower the extinction of sea salt particles since the hygroscopicity of a mixed nitrate-ammonium-sea salt particle is less than that of pure sea salt. The direct anthropogenic forcing of particulate nitrate and ammonium at the top of the atmosphere (TOA is estimated to be −0.12 W m−2. Nitrate, ammonium and nitric acid gas also affect aerosol activation and the reflectivity of clouds. The first aerosol indirect forcing by anthropogenic nitrate (gas plus aerosol and ammonium is estimated to be −0.09 W m−2 at the TOA, almost all of which is due to condensation of nitric acid gas onto growing droplets (−0.08 W m−2.

  4. Ammonium Inhibits Chromomethylase 3-Mediated Methylation of the Arabidopsis Nitrate Reductase Gene NIA2

    Science.gov (United States)

    Kim, Joo Yong; Kwon, Ye Jin; Kim, Sung-Il; Kim, Do Youn; Song, Jong Tae; Seo, Hak Soo

    2016-01-01

    Gene methylation is an important mechanism regulating gene expression and genome stability. Our previous work showed that methylation of the nitrate reductase (NR) gene NIA2 was dependent on chromomethylase 3 (CMT3). Here, we show that CMT3-mediated NIA2 methylation is regulated by ammonium in Arabidopsis thaliana. CHG sequences (where H can be A, T, or C) were methylated in NIA2 but not in NIA1, and ammonium [(NH4)2SO4] treatment completely blocked CHG methylation in NIA2. By contrast, ammonium had no effect on CMT3 methylation, indicating that ammonium negatively regulates CMT3-mediated NIA2 methylation without affecting CMT3 methylation. Ammonium upregulated NIA2 mRNA expression, which was consistent with the repression of NIA2 methylation by ammonium. Ammonium treatment also reduced the overall genome methylation level of wild-type Arabidopsis. Moreover, CMT3 bound to specific promoter and intragenic regions of NIA2. These combined results indicate that ammonium inhibits CMT3-mediated methylation of NIA2 and that of other target genes, and CMT3 selectively binds to target DNA sequences for methylation. PMID:26834755

  5. Effects of salinity induced by ammonium sulfate fertilizer on root and shoot growth of highbush blueberry

    Science.gov (United States)

    Ammonium sulfate fertilizer is commonly used in highbush blueberry, but due to a high relative salinity, it often causes salt damage, particularly in young plants, when too much of the fertilizer is applied. Three experiments were done to determine the sensitivity of ‘Bluecrop’ blueberry to ammonium...

  6. On the influence of thiamine and ammonium ions on alcoholic fermentation

    NARCIS (Netherlands)

    Maesen, Th.J.M.

    1953-01-01

    1. 1. In a glucose-sodium acetate medium of pH 5.6 the fermentation rate of bakers' yeast remains constant at a low level during several hours, while in the presence of ammonium sulphate it gradually increases. The rise is steeper in the presence of thiamine. 2. 2. After the ammonium ions have

  7. Field dissipation and storage stability of glufosinate ammonium and its metabolites in soil.

    Science.gov (United States)

    Zhang, Yun; Wang, Kai; Wu, Junxue; Zhang, Hongyan

    2014-01-01

    A simple analytical method was developed to measure concentrations of glufosinate ammonium and its metabolites, 3-methylphosphinico-propionic acid (MPP) and 2-methylphosphinico-acetic acid (MPA), in field soil samples. To determine the minimum quantification limit, samples were spiked at different levels (0.1, 0.5, and 1.0 mg/kg). Soil samples were extracted with ammonium hydroxide solution 5% (v/v), concentrated, and reacted with trimethyl orthoacetate (TMOA) in the presence of acetic acid for derivatization. The derivatives were quantified by gas chromatography (GC) using a flame photometric detector (FPD). The linear correlation coefficients of glufosinate ammonium, MPP, and MPA in soil were 0.991, 0.999, and 0.999, respectively. The recoveries of this method for glufosinate ammonium, MPP, and MPA in soil were 77.2-95.5%, 98.3-100.3%, and 99.3-99.6% with relative standard deviations (RSD) of 1.8-4.1%, 0.4-1.4%, and 1.3-2.0%, respectively. Glufosinate ammonium dissipated rapidly in soil to MPA in hours and gradually degraded to MPP. The half-life of glufosinate ammonium degradation in soil was 2.30-2.93 days in an open field. In soil samples stored at -20°C glufosinate ammonium was stable for two months. The results of this study should provide guidance for the safe application of the herbicide glufosinate ammonium to agricultural products and the environment.

  8. Precipitation of organic arsenic compounds and their degradation products during struvite formation

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jin-Biao; Yuan, Shoujun [School of Civil Engineering, Hefei University of Technology, Hefei 230009 (China); Institute of Water Treatment and Wastes Reutilization, Hefei University of Technology, Hefei 230009 (China); Wang, Wei, E-mail: dwhit@126.com [School of Civil Engineering, Hefei University of Technology, Hefei 230009 (China); Institute of Water Treatment and Wastes Reutilization, Hefei University of Technology, Hefei 230009 (China); Hu, Zhen-Hu, E-mail: zhhu@hfut.edu.cn [School of Civil Engineering, Hefei University of Technology, Hefei 230009 (China); Institute of Water Treatment and Wastes Reutilization, Hefei University of Technology, Hefei 230009 (China); Yu, Han-Qing [Department of Chemistry, University of Science & Technology of China, Hefei 230026 (China)

    2016-11-05

    Highlights: • Organic and inorganic arsenic compounds precipitated during struvite formation. • Precipitation of organic arsenic compounds in struvite decreased with increasing pH. • Arsenate easily precipitate in struvite as compared to organic arsenic compounds. • Arsenic compounds in solution affected the shape of struvite crystallization products. - Abstract: Roxarsone (ROX) and arsanilic acid (ASA) have been extensively used as organoarsenic animal feed additives. Organic arsenic compounds and their degradation products, arsenate (As(V)) and arsenite (As(III)), exist in the effluent from anaerobic reactors treating animal manure contaminated by ROX or ASA with ammonium (NH{sub 4}{sup +}-N) and phosphate (PO{sub 4}{sup 3−}-P) together. Therefore, arsenic species in the effluent might be involved in the struvite formation process. In this study, the involvement of organic arsenic compounds and their degradation products As(V) and As(III) in the struvite crystallization was investigated. The results demonstrated that arsenic compounds did not substantially affect the PO{sub 4}{sup 3−}-P recovery, but confirmed the precipitation of arsenic during struvite formation. The precipitation of arsenic compounds in struvite was considerably affected by a solution pH from 9.0 to 11.0. With an increase in pH, the content of ASA and ROX in the precipitation decreased, but the contents of As(III) and As(V) increased. In addition, the arsenic content of As(V) in the struvite was higher than that of As(III), ASA and ROX. The results indicated that the struvite could be contaminated when the solution contains arsenic species, but that could be minimized by controlling the solution pH and maintaining anaerobic conditions during struvite formation.

  9. Antimicrobial Nanocomposites Prepared from Montmorillonite/Ag+/Quaternary Ammonium Nitrate

    Directory of Open Access Journals (Sweden)

    Lin Zhang

    2018-01-01

    Full Text Available Nanocomposites of Ag with organic montmorillonite (Ag-OMMT, Ag with montmorillonite (Ag-MMT, and organic montmorillonite (OMMT were successfully prepared via a one-step solution-intercalated method. Sodium MMT, silver nitrate, and dimethyl octadecyl hydroxy ethyl ammonium nitrate were used as precursors. X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and energy dispersive spectroscopy analyses confirmed that the MMT layers were intercalated, and Ag+ was partly reduced to silver nanoparticles with diameters within 10–20 nm in Ag-OMMT. The decomposition temperature of the organic cations in OMMT and Ag-OMMT increased to 220°C, as revealed by differential scanning calorimetry-thermogravimetric analysis. The antimicrobial activity of the nanocomposites was tested by measuring the minimum inhibitory concentration (MIC and killing rate. The MICs of Ag-OMMT against Staphylococcus aureus, Escherichia coli, and Candida albicans were 0.313, 2.5, and 0.625 mg/mL, respectively. Because of the presence of quaternary ammonium nitrate, Ag-OMMT has a better MIC against Gram-positive bacteria compared to Gram-negative bacteria and fungi. OMMT did not show antimicrobial activity against Escherichia coli and Candida albicans. In 2 h, 0.0125 mg/mL Ag-OMMT could kill 100% of S. aureus, E. coli, and C. albicans in solution, and Ag-MMT could kill 99.995% of S. aureus, 90.15% of E. coli, and 93.68% of C. albicans. These antimicrobial functional nanocomposites have the potential for application in the area of surface decoration films.

  10. The production of sinterable uranium dioxide from ammonium diuranate

    International Nuclear Information System (INIS)

    Fane, A.G.; Le Page, A.H.

    1975-02-01

    The development of a 0.13 m diameter pulsed fluidised bed reactor for the continuous production of sinterable uranium dioxide from ammonium diuranate is described. Calcination-reduction at 670 to 680 0 C produced powders with surface areas of 4 to 6 m 2 g -1 giving pellet densities in excess of 10.6 g cm -3 . Sinterability was relatively insensitive to changes in operating conditions, provided the availability of hydrogen was adequate, for gas flow rates in the range 0.95 to 1.4 l S -1 , pulse frequencies of 0.5 and 0.75 Hz and mean residence times of the solids from 0.6 to 1.4 hours. Sinterability was shown to be improved either by use of higher input concentrations, or by use of a secondary flow of hydrogen (about 5 per cent of input) fed into the powder collection system and flowing countercurrent to the UO 2 product. The maximum throughput of 17 kg UO 2 h -1 (0.6 hours mean residence time) required only 120 per cent of the stoichiometric requirement at an input concentration of 50 vol.per cent with secondary hydrogen flow. Results are given for studies of the kinetics of reduction of calcined ammonia diuranate in hydrogen and the residence time distribution of solids in a pulsed fluidised bed. Estimates based on these data suggested that the overall conversion of ammonium diuranate to uranium dioxide in the continuously operated pulsed fluidised bed reactor was in excess of 99 per cent. Continuous stabilisation of the UO 2 product was demonstrated at 12 kg h -1 or UO 2 , in a 0.15 m diameter glass stabiliser, using 10 vol.per cent air in nitrogen and a temperature of about 50 0 C. (author)

  11. Cold Case: Radar investigation of ammonium sulfate cryovolcanism on Titan

    Science.gov (United States)

    Thomann, C.; Hayes, A. G.; Hofgartner, J.; Lunine, J. I.; Le Gall, A.

    2012-12-01

    The detection of a large tidal k2 value from Cassini [1] constitutes very strong evi-dence for a subcrustal ocean, most plausibly dominated by water. However, the secondary constituents are not known. One interesting possibility that has received scant attention in analysis of surface data sets is that the ocean contain aqueous ammonium sulfates, which erupted on the surface in the past to create vast, smooth plains [2]. We adopt the hypothesis that the undifferentiated plains—the "bland-lands" in the mid-latitudes of Titan—are these deposits, and test it using radiometry with SAR data. Lopez et al (this conference) investigate the global distribution and possible origin of this type of unit. We extracted SAR and radiometry-during-SAR data sets from the PDS, and pro-duced maps of brightness temperatures. The SAR imagery was used to identify locations where crossovers exist -some of which are in the undifferentiated plains--and hence where brightness temperatures at different incidence angles are available. We derived emissivities from the data using a simple radiometric model [3] to ac-count for the brightness temperature differences as a function of surface roughness, volume scattering and emissivity. We test the hypothesis by assessing whether the derived emissivities and volume scattering in the bland-lands are consistent with the model cryoclastic ash of ice and ammonium sulfate proposed in [2], distinct from that in other terrains. [1] L. Iess, R.A. Jacobson, M. Ducci, D.J. Stevenson, J.I. Lunine, J.W. Armstrong, S.W. Asmar, P. Racioppa, N.J. Rappaport, P. Tortora, Science, 337, 457 (2012). [2] A.D. Fortes, P.M. Grinrod, S.K. Trickett, L. Vocadlo. Icarus, 188, 139 (2007). [3] T.L. White and J.R. Cogdell. The Moon, 6, 235 (1973).

  12. Anaerobic ammonium oxidation by anammox bacteria in the Black Sea RID B-8834-2011

    DEFF Research Database (Denmark)

    Kuypers, MMM; Sliekers, AO; Lavik, G.

    2003-01-01

    ). Here we provide evidence for bacteria that anaerobically oxidize ammonium with nitrite to N(2) in the world's largest anoxic basin, the Black Sea. Phylogenetic analysis of 16S ribosomal RNA gene sequences shows that these bacteria are related to members of the order Planctomycetales performing...... the anammox (anaerobic ammonium oxidation) process in ammonium-removing bioreactors(3). Nutrient profiles, fluorescently labelled RNA probes, (15)N tracer experiments and the distribution of specific 'ladderane' membrane lipids(4) indicate that ammonium diffusing upwards from the anoxic deep water is consumed...... by anammox bacteria below the oxic zone. This is the first time that anammox bacteria have been identified and directly linked to the removal of fixed inorganic nitrogen in the environment. The widespread occurrence of ammonium consumption in suboxic marine settings(5-7) indicates that anammox might...

  13. Removal of ammonium ions from wastewater: A short review in development of efficient methods

    Directory of Open Access Journals (Sweden)

    V.K. Gupta

    2015-04-01

    Full Text Available Ammonium ions wastewater pollution has become one of the most serious environmental problems today. The treatment of ammonium ions is a special concern due to their recalcitrance and persistence in the environment. In recent years, various methods for ammonium ion removal from wastewater have been extensively studied. This paper reviews the current methods that have been used to treat ammonium ion wastewater and evaluates these techniques. These technologies include ion exchange, adsorption, biosorption, wet air oxidation, biofiltration, diffused aeration, nitrification and denitrification methods. About 75 published studies (1979-2015 are reviewed in this paper. It is evident from the literature survey articles that ion exchange, adsorption and biological technology are the most frequently studied for the treatment of ammonium ion wastewater.

  14. Precipitation chemistry in central Amazonia

    Science.gov (United States)

    Andreae, M. O.; Talbot, R. W.; Berresheim, H.; Beecher, K. M.

    1990-01-01

    Rain samples from three sites in central Amazonia were collected over a period of 6 weeks during the 1987 wet season and analyzed for ionic species and dissolved organic carbon. A continuous record of precipitation chemistry and amount was obtained at two of these sites, which were free from local or regional pollution, for a time period of over 1 month. The volume-weighted mean concentrations of most species were found to be about a factor of 5 lower during the wet season compared with previous results from the dry season. Only sodium, potassium, and chloride showed similar concentrations in both seasons. When the seasonal difference in rainfall amount is taken into consideration, the deposition fluxes are only slightly lower for most species during the wet season than during the dry season, again with the exception of chloride, potassium, and sodium. Sodium and chloride are present in the same ratio as in sea salt; rapid advection of air masses of marine origin to the central Amazon Basin during the wet season may be responsible for the observed higher deposition flux of these species. Statistical analysis suggests that sulfate is, to a large extent, of marine (sea salt and biogenic) origin, but that long-range transport of combustion-derived aerosols also makes a significant contribution to sulfate and nitrate levels in Amazonian rain. Organic acid concentrations in rain were responsible for a large fraction of the observed precipitation acidity; their concentration was strongly influenced by gas/liquid interactions.

  15. Role of ambient ammonia in particulate ammonium formation at a rural site in the North China Plain

    Science.gov (United States)

    Meng, Zhaoyang; Xu, Xiaobin; Lin, Weili; Ge, Baozhu; Xie, Yulin; Song, Bo; Jia, Shihui; Zhang, Rui; Peng, Wei; Wang, Ying; Cheng, Hongbing; Yang, Wen; Zhao, Huarong

    2018-01-01

    The real-time measurements of NH3 and trace gases were conducted, in conjunction with semi-continuous measurements of water-soluble ions in PM2.5 at a rural site in the North China Plain (NCP) from May to September 2013 in order to better understand chemical characteristics of ammonia and the impact of secondary ammonium aerosols on formation in the NCP. Extremely high NH3 and NH4+ concentrations were observed after a precipitation event within 7-10 days following urea application. Elevated NH3 levels coincided with elevated NH4+, indicating that NH3 likely influenced particulate ammonium mass. For the sampling period, the average conversion / oxidation ratios for NH4+ (NHR), SO42- (SOR), and NO3- (NOR) were estimated to be 0.30, 0.64, and 0.24, respectively. The increased NH3 concentrations, mainly from agricultural activities and regional transport, coincided with the prevailing meteorological conditions. The high NH3 level with NHR of about 0.30 indicates that the emission of NH3 in the NCP is much higher than needed for aerosol acid neutralisation, and NH3 plays an important role in the formation of secondary aerosols as a key neutraliser. The hourly data obtained were used to investigate gas-aerosol partitioning characteristics using the thermodynamic equilibrium model ISORROPIA-II. Modelled SO42-, NO3-, and NH3 values agree well with the measurements, while the modelled NH4+ values largely underestimate the measurements. Our observation and modelling results indicate that strong acids in aerosol are completely neutralised. Additional NH4+ exists in aerosol, probably a result of the presence of a substantial amount of oxalic and other diacids.

  16. Interaction between Ammonium Toxicity and Green Tide Development Over Seagrass Meadows: A Laboratory Study.

    Directory of Open Access Journals (Sweden)

    Francisco Moreno-Marín

    Full Text Available Eutrophication affects seagrasses negatively by increasing light attenuation through stimulation of biomass of fast-growing, bloom-forming algae and because high concentrations of ammonium in the water can be toxic to higher plants. We hypothesized nevertheless, that moderate amounts of nitrophilic macroalgae that coexists with seagrasses under eutrophic conditions, can alleviate the harmful effects of eutrophication on seagrasses by reducing ammonium concentrations in the seawater to non-toxic levels because such algae have a very large capacity to take up inorganic nutrients. We studied therefore how combinations of different ammonium concentrations (0, 25 and 50 μM and different standing stocks of macroalgae (i.e. 0, 1 and 6 layers of Ulva sp. affected survival, growth and net production of the seagrass Zostera noltei. In the absence of Ulva sp., increasing ammonium concentrations had a negative influence on the performance of Z. noltei. The presence of Ulva sp. without ammonium supply had a similar, but slightly smaller, negative effect on seagrass fitness due to light attenuation. When ammonium enrichment was combined with presence of Ulva sp., Ulva sp. ameliorated some of negative effects caused by high ammonium availability although Ulva sp. lowered the availability of light. Benthic microalgae, which increased in biomass during the experiment, seemed to play a similar role as Ulva sp.--they contributed to remove ammonium from the water, and thus, aided to keep the ammonium concentrations experienced by Z. noltei at relatively non-toxic levels. Our findings show that moderate amounts of drift macroalgae, eventually combined with increasing stocks of benthic microalgae, may aid seagrasses to alleviate toxic effects of ammonium under eutrophic conditions, which highlights the importance of high functional diversity for ecosystem resistance to anthropogenic disturbance.

  17. Fabrication of ammonium perchlorate/copper-chromium oxides core-shell nanocomposites for catalytic thermal decomposition of ammonium perchlorate

    Energy Technology Data Exchange (ETDEWEB)

    Eslami, Abbas, E-mail: eslami@umz.ac.ir [Department of Inorganic Chemistry, Faculty of Chemistry, University of Mazandaran, P.O.Box 47416-95447, Babolsar (Iran, Islamic Republic of); Juibari, Nafise Modanlou [Department of Inorganic Chemistry, Faculty of Chemistry, University of Mazandaran, P.O.Box 47416-95447, Babolsar (Iran, Islamic Republic of); Hosseini, Seyed Ghorban [Department of Chemistry, Malek Ashtar University of Technology, P.O. Box 16765-3454, Tehran (Iran, Islamic Republic of)

    2016-09-15

    The ammonium perchlorate/Cu(II)-Cr(III)-oxides(AP/Cu-Cr-O) core-shell nanocomposites were in-situ prepared by deposition of copper and chromium oxides on suspended ammonium perchlorate particles in ethyl acetate as solvent. The results of differential scanning calorimetery (DSC) and thermal gravimetric analysis (TGA) experiments showed that the nanocomposites have excellent catalytic effect on the thermal decomposition of AP, so that the released heat increases up to about 3-fold over initial values, changing from 450 J/g for pure AP to 1510 J/g for most appropriate mixture. For better comparison, single metal oxide/AP core-shell nanocomposite have also been prepared and the results showed that they have less catalytic effect respect to mixed metal oxides system. Scanning electron microscopy (SEM) results revealed homogenous deposition of nanoparticles on the surface of AP and fabrication of core-shell structures. The kinetic parameters of thermal decomposition of both pure AP and AP/Cu-Cr-O samples have been calculated by Kissinger method and the results showed that the values of pre-exponential factor and activation energy are higher for AP/Cu-Cr-O nanocomposite. The better catalytic effect of Cu-Cr-O nanocomposites is probably attributed to the synergistic effect between Cu{sup 2+} and Cr{sup 3+} in the nanocomposites, smaller particle size and more crystal defect. - Highlights: • The Cu-Cr-O nanoparticles were synthesized by chemical liquid deposition method. • Then, the AP/Cu-Cr-O core-shell nanocomposites were prepared. • The core-shell samples showed high catalytic activity for AP decomposition. • Thermal decomposition of samples occurs at lower temperature range.

  18. Anaerobic ammonium oxidation in traditional municipal wastewater treatment plants with low-strength ammonium loading: Widespread but overlooked.

    Science.gov (United States)

    Wang, Shanyun; Peng, Yongzhen; Ma, Bin; Wang, Shuying; Zhu, Guibing

    2015-11-01

    Occurrence of anaerobic ammonium oxidation (anammox) in marine and freshwater systems has greatly changed our understanding of global nitrogen (N) cycle and promoted the investigation of the role and ecological features of anammox in anthropogenic ecosystems. This study focused on the spatio-temporal abundance, activity, and biodiversity of anammox bacteria in full-scale municipal wastewater treatment plants (WWTPs) via traditional nitrification/denitrification route with low-strength ammonium loading. The anammox bacteria were detected in all the treatment units at the five WWTPs tested, even in aerobic zones (dissolved oxygen >2 mg L(-1)) with abundance of 10(5)-10(7) hydrazine synthase (hzs) gene copies g(-1). The (15)N-isotope tracing technology revealed that the anammox rates in WWTPs ranged from 0.08 to 0.36 μmol N g(-1) h(-1) in winter and 0.12-1.20 μmol N g(-1) h(-1) in summer with contributions of 2.05-6.86% and 1.71-7.26% to N2 production, respectively. The diversity of anammox bacteria in WWTPs was distributed over only two genera, Brocadia and Kuenenia. Additionally, the exploration of potential interspecies relationships indicated that ammonia oxidation bacteria (AOB) was the major nitrite-substrate producer for anammox during nitrification, while Nitrospira, a nitrite oxidation bacteria (NOB), was the potential major competitor for nitrite. These results suggested the contribution of N-removal by the widespread of anammox has been overlooked in traditional municipal WWTPs, and the ecological habitats of anammox bacteria in anthropogenic ecosystems are much more abundant than previously assumed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Fabrication of ammonium perchlorate/copper-chromium oxides core-shell nanocomposites for catalytic thermal decomposition of ammonium perchlorate

    International Nuclear Information System (INIS)

    Eslami, Abbas; Juibari, Nafise Modanlou; Hosseini, Seyed Ghorban

    2016-01-01

    The ammonium perchlorate/Cu(II)-Cr(III)-oxides(AP/Cu-Cr-O) core-shell nanocomposites were in-situ prepared by deposition of copper and chromium oxides on suspended ammonium perchlorate particles in ethyl acetate as solvent. The results of differential scanning calorimetery (DSC) and thermal gravimetric analysis (TGA) experiments showed that the nanocomposites have excellent catalytic effect on the thermal decomposition of AP, so that the released heat increases up to about 3-fold over initial values, changing from 450 J/g for pure AP to 1510 J/g for most appropriate mixture. For better comparison, single metal oxide/AP core-shell nanocomposite have also been prepared and the results showed that they have less catalytic effect respect to mixed metal oxides system. Scanning electron microscopy (SEM) results revealed homogenous deposition of nanoparticles on the surface of AP and fabrication of core-shell structures. The kinetic parameters of thermal decomposition of both pure AP and AP/Cu-Cr-O samples have been calculated by Kissinger method and the results showed that the values of pre-exponential factor and activation energy are higher for AP/Cu-Cr-O nanocomposite. The better catalytic effect of Cu-Cr-O nanocomposites is probably attributed to the synergistic effect between Cu 2+ and Cr 3+ in the nanocomposites, smaller particle size and more crystal defect. - Highlights: • The Cu-Cr-O nanoparticles were synthesized by chemical liquid deposition method. • Then, the AP/Cu-Cr-O core-shell nanocomposites were prepared. • The core-shell samples showed high catalytic activity for AP decomposition. • Thermal decomposition of samples occurs at lower temperature range.

  20. Competition for Ammonium between Plant-Roots and Nitrifying and Heterotrophic Bacteria and the Effects of Protozoan Grazing

    NARCIS (Netherlands)

    Verhagen, F.J.M.; Laanbroek, H.J.; Woldendorp, J.W.

    1995-01-01

    The competition for limiting amounts of ammonium between the chemolithotrophic ammonium-oxidizing species Nitrosomonas europaea, the heterotrophic species Arthrobacter globiformis and roots of Plantago lanceolata (Ribwort plantain) was studied in a series of model systems of increasing complexity,

  1. Forced normalisation precipitated by lamotrigine.

    Science.gov (United States)

    Clemens, Béla

    2005-10-01

    To report two patients with lamotrigine-induced forced normalization (FN). Evaluation of the patient files, EEG, and video-EEG records, with special reference to the parallel clinical and EEG changes before, during, and after FN. This is the first documented report of lamotrigine-induced FN. The two epileptic patients (one of them was a 10-year-old girl) were successfully treated with lamotrigine. Their seizures ceased and interictal epileptiform events disappeared from the EEG record. Simultaneously, the patients displayed de novo occurrence of psychopathologic manifestations and disturbed behaviour. Reduction of the daily dose of LTG led to disappearance of the psychopathological symptoms and reappearance of the spikes but not the seizures. Lamotrigine may precipitate FN in adults and children. Analysis of the cases showed that lamotrigine-induced FN is a dose-dependent phenomenon and can be treated by reduction of the daily dose of the drug.

  2. Electrostatic precipitator for air cleaning

    Energy Technology Data Exchange (ETDEWEB)

    Albertsson, P.; Eriksson, R.; Vlastos, A.

    1981-03-31

    An electrostatic precipitator is disclosed for air cleaning wherein the air passes through in two steps: first passing through a charging portion and next through a separation portion. The charging portion includes wires positioned parallel to and between parallel metal sheets, the wires having an electric potential other than that of the metal sheets. The separation portion includes plural parallel metal sheets, each of which has an electric potential other than that of adjacent metal sheets. The charging portion includes two or more wires between each pair of metal sheets, and the metal sheets of the charging portion extend through and constitute some of the metal sheets of the separation portion, between which are disposed addition metal sheets of an odd number.

  3. Complexation of uranyl ion. I. IR spectroscopic study of the composition of precipitates in sulfate and carbonate media

    International Nuclear Information System (INIS)

    Buskina, I.A.; Stupin, N.P.; Kakhaeva, T.V.; Rodionov, V.V.; Zhukova, N.G.; Vodolazov, L.I.

    1987-01-01

    The composition of uranium(VI) complexes separated from uranyl sulfate solutions at various pH values was studied by IR spectroscopy. A difference was found in the composition of sulfate complexes separated by precipitation at pH 1.5-4.0 and 4-6. At pH above 4 desulfatization occurs, with formation of polymeric ions. At pH 7 in the presence of ammonium bicarbonate, uranyl complexes form with bidentate coordination of the CO 3 2- group

  4. Experimental study of diffuse auroral precipitations

    International Nuclear Information System (INIS)

    Mouaia, K.

    1983-01-01

    First chapter is devoted to low energy electron precipitation in the evening sector of the auroral magnetosphere, during quiet and disturbed magnetic periods. Four subjects are studied in detail: the latitude distribution of the varied auroral forms and their relations to external magnetosphere; the time coefficients related to precipitations, the form and the dynamic of the diffuse precipitation equatorial frontier; the precipitation effect on the ionosphere concentration. The last part of the chapter shows that the plasma convection in the magnetosphere, associated to wave-particle interactions near the equatorial accounts for the principal characteristics of the evening sector diffuse electronic precipitations. The second chapter deals with subauroral precipitations of low energy ions, after the magnetospheric substorms, in the high latitude regions of the morning sector [fr

  5. Proton- and ammonium-sensing by histaminergic neurons controlling wakefulness.

    Science.gov (United States)

    Yanovsky, Yevgenij; Zigman, Jeffrey M; Kernder, Anna; Bein, Alisa; Sakata, Ichiro; Osborne-Lawrence, Sherri; Haas, Helmut L; Sergeeva, Olga A

    2012-01-01

    The histaminergic neurons in the tuberomamillary nucleus (TMN) of the posterior hypothalamus are involved in the control of arousal. These neurons are sensitive to hypercapnia as has been shown in experiments examining c-Fos expression, a marker for increased neuronal activity. We investigated the mechanisms through which TMN neurons respond to changes in extracellular levels of acid/CO(2). Recordings in rat brain slices revealed that acidification within the physiological range (pH from 7.4 to 7.0), as well as ammonium chloride (5 mM), excite histaminergic neurons. This excitation is significantly reduced by antagonists of type I metabotropic glutamate receptors and abolished by benzamil, an antagonist of acid-sensing ion channels (ASICs) and Na(+)/Ca(2+) exchanger, or by ouabain which blocks Na(+)/K(+) ATPase. We detected variable combinations of 4 known types of ASICs in single TMN neurons, and observed activation of ASICs in single dissociated TMN neurons only at pH lower than 7.0. Thus, glutamate, which is known to be released by glial cells and orexinergic neurons, amplifies the acid/CO(2)-induced activation of TMN neurons. This amplification demands the coordinated function of metabotropic glutamate receptors, Na(+)/Ca(2+) exchanger and Na(+)/K(+) ATPase. We also developed a novel HDC-Cre transgenic reporter mouse line in which histaminergic TMN neurons can be visualized. In contrast to the rat, the mouse histaminergic neurons lacked the pH 7.0-induced excitation and displayed only a minimal response to the mGluR I agonist DHPG (0.5 μM). On the other hand, ammonium-induced excitation was similar in mouse and rat. These results are relevant for the understanding of the neuronal mechanisms controlling acid/CO(2)-induced arousal in hepatic encephalopathy and obstructive sleep apnoea. Moreover, the new HDC-Cre mouse model will be a useful tool for studying the physiological and pathophysiological roles of the histaminergic system.

  6. Upgrading fertilizer production wastewater effluent quality for ammonium discharges through ion exchange with clinoptilolite.

    Science.gov (United States)

    Beler-Baykal, B; Allar, A D

    2008-06-01

    It had previously been shown that ammonium selective natural zeolite clinoptilolite may be used successfully as an ion exchanger for ammonium removal and nitrogen control from domestic wastewater. The process had been reported to be acceptable either by itself alone or as an upgrade. In this work, the possibility of using clinoptilolite for ammonium removal from fertilizer production wastewater was investigated. The fertilizer plant under consideration was rather a non-typical one with a lower ammonium strength than what is normally expected, and a variable effluent concentration. Batch experiments were performed to assess the capacity of clinoptilolite towards ammonium removal from an industrial wastewater at two different pHs. Flow experiments for the characterization of system behavior under continuous feeding conditions at different contact times were conducted for breakthrough analysis. Both real and simulated fertilizer wastewater samples were investigated and the results have shown that the real one may successfully be represented by the simulated one. Experimental results have shown that surface capacities exceeding 14 mg ammonium g(-1) clinoptilolite could be attained, complete removal of ammonium may be achieved with empty bed contact times of 10 min or higher and ion exchange with clinoptilolite could be used successfully to comply with the effluent standards given for the fertilizer plant.

  7. [Effects of exogenous silicon on physiological characteristics of cucumber seedlings under ammonium stress].

    Science.gov (United States)

    Gao, Qing-Hai; Wang, Ya-Kun; Lu, Xiao-Min; Jia, Shuang-Shuang

    2014-05-01

    The present study evaluated the effects of exogenous silicon on growth and physiological characteristics of hydroponically cultured cucumber seedlings under ammonium stress. The results showed that the growth, especially the aerial part growth of cucumber seedlings cultured with ammonium were significantly inhibited than those with nitrate, especially after treatment for 10 d, the aerial part fresh mass of cucumber seedlings were reduced 6.17 g per plant. The accumulation of reactive oxygen species (ROS) was also promoted in cucumber seedlings under ammonium, and the contents of O2*- and H2O2 were significantly increased in cucumber leaves. With the exogenous silicon treatment, the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX) were significantly improved, the ability to remove reactive oxygen species was enhanced, the contents of O2*- and H2O2 were significantly reduced in cucumber leaves, decreasing the reactive oxygen damage to the cell membrane, and the ratio of electrolyte leakage and the content of MDA in cucumber leaves. Also, with exogenous silicon treatment, the plasma membrane and activity of vacuolar membrane H(+)-ATP was significantly increased, transport capacity of intracellular proton was improved, and the level of ammonium in cucumber body was significantly reduced, thereby reducing the toxicity of ammonium. In conclusion, exogenous silicon could relieve ammonium stress, by increasing the antioxidant enzyme activity, H(+)-ATP activity, and decreasing the ammonium content in cucumber seedlings.

  8. Ammonium recovery and energy production from urine by a microbial fuel cell.

    Science.gov (United States)

    Kuntke, P; Smiech, K M; Bruning, H; Zeeman, G; Saakes, M; Sleutels, T H J A; Hamelers, H V M; Buisman, C J N

    2012-05-15

    Nitrogen recovery through NH(3) stripping is energy intensive and requires large amounts of chemicals. Therefore, a microbial fuel cell was developed to simultaneously produce energy and recover ammonium. The applied microbial fuel cell used a gas diffusion cathode. The ammonium transport to the cathode occurred due to migration of ammonium and diffusion of ammonia. In the cathode chamber ionic ammonium was converted to volatile ammonia due to the high pH. Ammonia was recovered from the liquid-gas boundary via volatilization and subsequent absorption into an acid solution. An ammonium recovery rate of 3.29 g(N) d(-1) m(-2) (vs. membrane surface area) was achieved at a current density of 0.50 A m(-2) (vs. membrane surface area). The energy balance showed a surplus of energy 3.46 kJ g(N)(-1), which means more energy was produced than needed for the ammonium recovery. Hence, ammonium recovery and simultaneous energy production from urine was proven possible by this novel approach. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. An optical-density-based feedback feeding method for ammonium concentration control in Spirulina platensis cultivation.

    Science.gov (United States)

    Bao, Yilu; Wen, Shumei; Cong, Wei; Wu, Xia; Ning, Zhengxiang

    2012-07-01

    Cultivation of Spirulina platensis using ammonium salts or wastewater containing ammonium as alternative nitrogen sources is considered as a commercial way to reduce the production cost. In this research, by analyzing the relationship between biomass production and ammonium- N consumption in the fed-batch culture of Spirulina platensis using ammonium bicarbonate as a nitrogen nutrient source, an online adaptive control strategy based on optical density (OD) measurements for controlling ammonium feeding was presented. The ammonium concentration was successfully controlled between the cell growth inhibitory and limiting concentrations using this OD-based feedback feeding method. As a result, the maximum biomass concentration (2.98 g/l), productivity (0.237 g/l·d), nitrogen-to-cell conversion factor (7.32 gX/gN), and contents of protein (64.1%) and chlorophyll (13.4 mg/g) obtained by using the OD-based feedback feeding method were higher than those using the constant and variable feeding methods. The OD-based feedback feeding method could be recognized as an applicable way to control ammonium feeding and a benefit for Spirulina platensis cultivations.

  10. To measure ammonia and the ammonium-ion in high concentrations with sensitrodes; Messreihen mit Ammoniak- und Ammonium-Sensitroden in ungewoehnlich hohen Konzentrationsbereichen

    Energy Technology Data Exchange (ETDEWEB)

    Brosche, P. [DBI-EWI GmbH, Freiberg (Germany)

    1996-08-01

    Ammonia up to 8 Mol/kg and the ammonium-ion up to 5 Mol/kg were investigated by sensitrodes. Sensitrodes of different manufacturers, the influence of different salts, the temperature (25 and 50 C) and ammonia in mixture with the ammonium-ion were assessed in respect of the result for measuring. The functional correlation between the pH-value and the logarithmus for the ratio of ammonium-ion to ammonia in respect of the equation from Henderson and Hasselbalch was examined. The given concentration for ammonia respectively the ammonium-ion was compared with the calculated concentration of the calibration curve. The investigated sensitrodes may be installed in the manufacturing of ammonium salts in mixture with ammonia as measuring and controlling unit. (orig.) [Deutsch] Ammoniak bis 8 mol/kg und das Ammoniumion bis 5 mol/kg wurden mittels Sensitroden untersucht. Bewertet wurden Sensitroden verschiedener Hersteller, der Einfluss von Salzen, der Temperatur (25 und 50 C) und Ammoniak im Gemisch mit dem Ammoniumion auf das Messergebnis. Der funktionale Zusammenhang zwischen dem pH-Wert und dem Logarithmus des Verhaeltnisses von Ammoniumion und Ammoniak entsprechend der Gleichung von Henderson und Hasselbalch wurde untersucht. Die eingegebenen Konzentrationen an Ammoniak bzw. des Ammoniumions wurden mit den aus den Kalibrierungskurven errechneten Konzentrationen verglichen. Die untersuchten Sensitroden koennen in der Produktion von Ammoniumsalzen im Gemisch mit Ammoniak als Mess- und Steuergeraet eingesetzt werden. (orig.)

  11. Global Precipitation Measurement (GPM) Mission Development Status

    Science.gov (United States)

    Azarbarzin, Ardeshir Art

    2011-01-01

    Mission Objective: (1) Improve scientific understanding of the global water cycle and fresh water availability (2) Improve the accuracy of precipitation forecasts (3) Provide frequent and complete sampling of the Earth s precipitation Mission Description (Class B, Category I): (1) Constellation of spacecraft provide global precipitation measurement coverage (2) NASA/JAXA Core spacecraft: Provides a microwave radiometer (GMI) and dual-frequency precipitation radar (DPR) to cross-calibrate entire constellation (3) 65 deg inclination, 400 km altitude (4) Launch July 2013 on HII-A (5) 3 year mission (5 year propellant) (6) Partner constellation spacecraft.

  12. Preparation of LuAG Powders with Single Phase and Good Dispersion for Transparent Ceramics Using Co-Precipitation Method

    Directory of Open Access Journals (Sweden)

    Liangjie Pan

    2015-08-01

    Full Text Available The synthesis of pure and well dispersed lutetium aluminum garnet (LuAG powder is crucial and important for the preparation of LuAG transparent ceramics. In this paper, high purity and well dispersed LuAG powders have been synthesized via co-precipitation method with lutetium nitrate and aluminum nitrate as raw materials. Ammonium hydrogen carbonate (AHC was used as the precipitant. The influence of aging time, pH value, and dripping speed on the prepared LuAG powders were investigated. It showed that long aging duration (>15 h with high terminal pH value (>7.80 resulted in segregation of rhombus Lu precipitate and Al precipitate. By decreasing the initial pH value or accelerating the dripping speed, rhombus Lu precipitate was eliminated and pure LuAG nano powders were synthesized. High quality LuAG transparent ceramics with transmission >75% at 1064 nm were fabricated using these well dispersed nano LuAG powders.

  13. Recovery of Vanadium from H2SO4-HF Acidic Leaching Solution of Black Shale by Solvent Extraction and Precipitation

    Directory of Open Access Journals (Sweden)

    Xingbin Li

    2016-03-01

    Full Text Available The recovery of vanadium from sulfuric and hydrofluoric mixed acid solutions generated by the direct leaching of black shale was investigated using solvent extraction and precipitation methods. The process consisted of reduction, solvent extraction, and stripping, followed by precipitation and calcination to yield vanadium pentoxide. The influence of various operating parameters on the extraction and recovery of vanadium was studied. Vanadium (IV was selectively extracted using a mixture of 10% (v/v di(2-ethylhexylphosphoric acid and 5% (v/v tri-n-butylphosphate in sulfonated kerosene. Using six extraction and five stripping stages, the extraction efficiency for vanadium was 96.7% and the stripping efficiency was 99.7%. V2O5 with a purity of 99.52% was obtained by oxidation of the loaded strip solution and precipitation of ammonium polyvanadate at pH 1.8 to 2.2, followed by calcination of the dried precipitate at 550 °C for 2 h. It was concluded that the combination of solvent extraction and precipitation is an efficient method for the recovery of vanadium from a multi-element leach solution generated from black shale.

  14. Asymmetric responses of primary productivity to precipitation extremes: A synthesis of grassland precipitation manipulation experiments.

    Science.gov (United States)

    Wilcox, Kevin R; Shi, Zheng; Gherardi, Laureano A; Lemoine, Nathan P; Koerner, Sally E; Hoover, David L; Bork, Edward; Byrne, Kerry M; Cahill, James; Collins, Scott L; Evans, Sarah; Gilgen, Anna K; Holub, Petr; Jiang, Lifen; Knapp, Alan K; LeCain, Daniel; Liang, Junyi; Garcia-Palacios, Pablo; Peñuelas, Josep; Pockman, William T; Smith, Melinda D; Sun, Shanghua; White, Shannon R; Yahdjian, Laura; Zhu, Kai; Luo, Yiqi

    2017-10-01

    Climatic changes are altering Earth's hydrological cycle, resulting in altered precipitation amounts, increased interannual variability of precipitation, and more frequent extreme precipitation events. These trends will likely continue into the future, having substantial impacts on net primary productivity (NPP) and associated ecosystem services such as food production and carbon sequestration. Frequently, experimental manipulations of precipitation have linked altered precipitation regimes to changes in NPP. Yet, findings have been diverse and substantial uncertainty still surrounds generalities describing patterns of ecosystem sensitivity to altered precipitation. Additionally, we do not know whether previously observed correlations between NPP and precipitation remain accurate when precipitation changes become extreme. We synthesized results from 83 case studies of experimental precipitation manipulations in grasslands worldwide. We used meta-analytical techniques to search for generalities and asymmetries of aboveground NPP (ANPP) and belowground NPP (BNPP) responses to both the direction and magnitude of precipitation change. Sensitivity (i.e., productivity response standardized by the amount of precipitation change) of BNPP was similar under precipitation additions and reductions, but ANPP was more sensitive to precipitation additions than reductions; this was especially evident in drier ecosystems. Additionally, overall relationships between the magnitude of productivity responses and the magnitude of precipitation change were saturating in form. The saturating form of this relationship was likely driven by ANPP responses to very extreme precipitation increases, although there were limited studies imposing extreme precipitation change, and there was considerable variation among experiments. This highlights the importance of incorporating gradients of manipulations, ranging from extreme drought to extreme precipitation increases into future climate change

  15. Noncovalent Complexation of Monoamine Neurotransmitters and Related Ammonium Ions by Tetramethoxy Tetraglucosylcalix[4]arene

    Science.gov (United States)

    Torvinen, Mika; Kalenius, Elina; Sansone, Francesco; Casnati, Alessandro; Jänis, Janne

    2012-02-01

    The noncovalent complexation of monoamine neurotransmitters and related ammonium and quaternary ammonium ions by a conformationally flexible tetramethoxy glucosylcalix[4]arene was studied by electrospray ionization Fourier transform ion cyclotron resonance (ESI-FTICR) mass spectrometry. The glucosylcalixarene exhibited highest binding affinity towards serotonin, norepinephrine, epinephrine, and dopamine. Structural properties of the guests, such as the number, location, and type of hydrogen bonding groups, length of the alkyl spacer between the ammonium head-group and the aromatic ring structure, and the degree of nitrogen substitution affected the complexation. Competition experiments and guest-exchange reactions indicated that the hydroxyl groups of guests participate in intermolecular hydrogen bonding with the glucocalixarene.

  16. Ammonium assimilation and regeneration by size-fractionated plankton in permanently well-mixed temperate waters

    Digital Repository Service at National Institute of Oceanography (India)

    LeCorre, P.; Wafar, M.V.M.; Helguen, S.L.; Maguer, J.F.

    -at N I"1 Ir1) (Figure 2b) and correlated well with assimilation (A) (r = 0.97; P < 0.01; A/R ratio 1.65) and ambient ammonium con- centrations (r = 0.73; P < 0.01). As with assimilation, the relationship between regeneration and ambient ammonium... view (Malone, 1980) that nanoplankton are twice as photosynthetically active as netplankton. As ammonium assimilation was not substrate limited even at maximum assimilation (L'Helguen et al., 1996) and other environmental con- ditions (light...

  17. Vapour pressure of ammonium chloride aerosol: Effect of temperature and humidity

    Science.gov (United States)

    Pio, Casimiro A.; Harrison, Roy M.

    The effect of relative humidity (RH) on the constant for dissociation of ammonium chloride into gaseous HCl and NH 3 has been estimated for different temperatures, using thermodynamic data. At RH over 75-85% the ammonium chloride aerosol exists in the liquid phase, with the dissociation constant two orders of magnitude lower at 98% RH than for solid aerosol at the same temperature. It is predicted that ammonium chloride aqueous aerosol forms predominantly in fogwater and cloud droplets, and in regions where local emissions of NH 3 are important.

  18. Properties of Extreme Precipitation and Their Uncertainties in 3-year GPM Precipitation Radar Data

    Science.gov (United States)

    Liu, N.; Liu, C.

    2017-12-01

    Extreme high precipitation rates are often related to flash floods and have devastating impacts on human society and the environments. To better understand these rare events, 3-year Precipitation Features (PFs) are defined by grouping the contiguous areas with nonzero near-surface precipitation derived using Global Precipitation Measurement (GPM) Ku band Precipitation Radar (KuPR). The properties of PFs with extreme precipitation rates greater than 20, 50, 100 mm/hr, such as the geographical distribution, volumetric precipitation contribution, seasonal and diurnal variations, are examined. In addition to the large seasonal and regional variations, the rare extreme precipitation rates often have a larger contribution to the local total precipitation. Extreme precipitation rates occur more often over land than over ocean. The challenges in the retrieval of extreme precipitation might be from the attenuation correction and large uncertainties in the Z-R relationships from near-surface radar reflectivity to precipitation rates. These potential uncertainties are examined by using collocated ground based radar reflectivity and precipitation retrievals.

  19. Acid deposition modelling and the interpretation of the United Kingdom secondary precipitation network data

    Science.gov (United States)

    Metcalfe, S. E.; Atkins, D. H. F.; Derwent, R. G.

    Acid deposition modelling calculations have been compared against the data obtained during the first year's operation of the United Kingdom Secondary Precipitation Network. The model adopted employed a single level trajectory approach to describe the coupled atmospheric chemistry and deposition of SO x NO y and NH x species. For the precipitation sulphate concentrations, the model results over the 47 network sites correlated well with the observations. When corrections were applied within the model calculations for background deposition and for dry deposition into the bulk collector, then the model results overestimated the precipitation sulphate observations by about 27%. For the precipitation nitrate concentrations, again the model results correlated well with the observations. Over the whole network, the model underestimated the observations by about 6% and no significant background correction was required for background sources. For the precipitation ammonium concentrations, good agreement with the observations could only be obtained if an additional ammonia source over and above that from animal manure was included in the model. One possibility investigated was exhalation from agricultural soils with an emission rate of 50-100 kg NH x ha -1 a -1. The model was able to reproduce the main features of the distributions of NO 2 and NH 3 in terms of gradients across the U.K. and in the location of the respective maxima. However, in both cases, severe underestimation by the model was apparent. The source of this underestimation was found to involve the assumption of complete vertical mixing in the model and the neglect of nocturnal stable layers.

  20. Toxic fumes from explosives: ammonium nitrate-fuel oil mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Chaiken, R.F.; Cook, E.B.; Ruhe, T.C.

    1974-01-01

    The Bureau of Mines has carried out experimental and theoretical studies with prilled and pulverized ammonium nitrate-fuel oil (AN-FO) mixtures containing varying amounts of fuel oil in an attempt to quantify the effects of stoichiometric composition, nonideal detonation behavior, and expansion volume on the production of CO, NO, and NO/sub 2/ fumes. Experimental fume measurements were obtained in the Bureau's large closed gallery facility (7.2 x 10/sup 4/ liter expansion chamber) and in the standard Crawshaw-Jones apparatus (90-liter expansion chamber) using a prepackaged charge configuration containing about 450 g of explosives. The theoretical calculation of toxic fumes was achieved with an equilibrium detonation code called TIGER. Contrary to initial expectations, the NO/sub x/ (= NO + NO/sub 2/) fumes from the large gallery test were found to be in essential agreement with the Crawshaw-Jones results. It was also concluded that TIGER calculations offer a good approach to the prediction of toxic fumes; there is a basic problem in extrapolating laboratory measurements of CO fumes to mine conditions, this being due to postdetonation oxidation of CO to CO/sub 2/; and the detonation velocity decay rate of an explosive is a useful experimental parameter for correlating toxic fumes production with nonideal detonation behavior.

  1. Equation of state, initiation, and detonation of pure ammonium nitrate

    Science.gov (United States)

    Robbins, D. L.; Sheffield, S. A.; Dattelbaum, D. M.; Velisavljevic, N.; Stahl, D. B.

    2009-06-01

    Ammonium nitrate (AN) is a widely used fertilizer and mining explosive throughout the world. One of the more common explosives using AN is called ANFO, a mixture of AN prills and fuel oil in a 94:6 ratio by weight. The AN prills are specially made to absorb the fuel oil, forming a mixture that reacts under shock loading through a diffusion-controlled process, resulting in a non-ideal explosive with detonation velocities around 4 km/s. While there are a number of studies on ANFO, there are only a few studies relating to the equation of state (EOS) and detonation properties of pure AN - resulting mainly from studies of accidents that have occurred during transportation of large quantities of AN. We present the results of a series of gas gun-driven plate impact experiments on pressed AN ranging in density from 1.72 to 0.9 g/cm^3. Several of the high density experiments were performed in front surface impact geometry, in which pressed AN disks were built into the projectile front and impacted onto LiF windows. Additional experiments at low density have been done in ``half cell'' multiple magnetic gauge gun experiments. From this work a complete unreacted EOS has been developed, as well as some initiation and detonation information. Additional high pressure x-ray diffraction experiments in diamond anvil cells have provided a static isotherm for AN.

  2. Modelling of biofilters for ammonium reduction in combined sewer overflow.

    Science.gov (United States)

    Henrichs, M; Welker, A; Uhl, M

    2009-01-01

    Biofiltration has proved to be a useful system to treat combined sewer overflow (CSO). The study presented uses numerical simulation to detect the critical operating conditions of the filter. The multi-component reactive transport module CW2D was used for the simulation study. Single-event simulations of lab-scale-column experiments with varying boundary conditions regarding the throttle outflow rate were carried out. For the calibration of the CW2D model measurement results of four experiments in two lab-scale columns were used. The model was validated by simulating four events of two further columns filled with the same filter material. These columns were operating with higher throttle outflow rates than the columns used for calibration. For ammonium (NH(4)-N) a good fit between measured and simulated data could be achieved. However, the comparison of simulated and measured effluent concentrations of nitrate (NO(3)-N) showed that there is a need for further investigations mainly due to the uncertainties in the degradation process during dry periods between the loadings.

  3. Mode of action of new organic ammonium salts

    International Nuclear Information System (INIS)

    Miko, M.; Gulasova, A.; Devinsky, F.

    1998-01-01

    The aim of this paper was primary biochemical screening of cytotoxic activity. The measure of the cytotoxic effect was the degree of inhibition of 14 C-adenine and 14 C-valine incorporation into TCA-insoluble fraction of Ehrlich ascites carcinoma (EAC) cells. The primary biochemical screening was carried out with the 12 new organic ammonium salts (OAS), from a homologous series of N-alkyl-(N 2 -dodekanoylethyl)-dimethylammonium bromide. In a first approach to determine the model of action of the cytotoxic active compounds, the kinetics of DNA, RNA and protein synthesis inhibition were examined using isotope incorporation. On the basis of primary screening, one of the most active compounds, namely N-octyl-N 2 -dodekanoylethyl)-dimethylammonium bromide was chosen for further biochemical studies. Selected OAS inhibited biosynthesis of nucleic acids indicated by incorporation of 14 C-adenine and biosynthesis of protein indicated by incorporation of 14 C-valine. From the results, it is obvious, that the biosynthesis of DNA, indicated by the incorporation of 14 -thymidine, was more sensitive than biosynthesis of RNA indicated by the incorporation of 14 C-uridine. OAS at the lower concentrations stimulated aerobic glycolysis of tumor cells. Such a stimulation of glycolysis at lower concentrations of OAS indicated a potential interference with respiratory processes in tumor cells, or in isolated mitochondria. We assumed that the cytotoxic effect of OAS could be consequence of cytolytic activity of OAS. (authors)

  4. Electrodes as Terminal Electron Acceptors in Anaerobic Ammonium Oxidation

    Science.gov (United States)

    Ruiz-Urigüen, M.; Jaffe, P. R.

    2017-12-01

    Anaerobic ammonium (NH4+) oxidation under iron (Fe) reducing conditions is a microbial- mediated process known as Feammox. This is a novel pathway in the nitrogen cycle, and a key process for alleviating NH4+ accumulation in anoxic soils, wetlands, and wastewater. Acidimicrobiaceae-bacterium A6, phylum Actinobacteria, are one type of autotrophic bacteria linked to this process. The Feammox-bacteria obtain their energy by oxidizing NH4+ and transferring the electrons to a terminal electron acceptor (TEA). Under environmental conditions, iron oxides are the TEAs. However, in this study we show that electrodes in Microbial Electrolysis Cells (MECs) or electrodes set in the field can be used as TEAs by Feammox-bacteria. The potential difference between electrodes is the driving force for electron transfer, making the reaction energetically feasible. Our results show that MECs containing Feammox cultures can remove NH4+ up to 3.5 mg/L in less than 4 hours, compared to an average of 9 mg/L in 2 weeks when cultured under traditional conditions. Concomitantly, MECs produce an average current of 30.5 A/m3 whilst dead bacteria produced low (application of Feammox-bacteria.

  5. Dissolution kinetics of calcined ulexite in ammonium sulfate solutions

    Directory of Open Access Journals (Sweden)

    Nizamettin Demirkıran

    2018-03-01

    Full Text Available Ulexite is one of the boron minerals, which include a respectable amount of hydration water. It can be used as a raw material in the production of boron compounds. Some part of water in the composition of ulexite can be removed from the solid matrix applying dehydration treatment, and a porous structure can be obtained to increase the reaction rate. In the present study, the effect of dehydration temperature on dissolution kinetics of ulexite in ammonium sulfate solutions was researched in a batch reactor utilizing the parameters of solution concentration, solid-to-liquid ratio, stirring speed and reaction temperature. It was determined that the dissolution rate of calcined material increased with increasing solution concentration and reaction temperature and with decreasing solid-to-liquid ratio. The highest dissolution rate was attained with the sample calcined at 150 °C. It was found that the dissolution rate fit to the first order pseudo-homogeneous model. The activation energy of the dissolution process was estimated to be 42 kJ·mol-1.

  6. Intensification of sonochemical degradation of ammonium perfluorooctanoate by persulfate oxidant.

    Science.gov (United States)

    Hao, Feifei; Guo, Weilin; Wang, Anqi; Leng, Yanqiu; Li, Helian

    2014-03-01

    Ammonium perfluorooctanoate (APFO) is an emerging environmental pollutant attracting significant attention due to its global distribution, high persistence, and bioaccumulation properties. The decomposition of APFO in aqueous solution with a combination of persulfate oxidant and ultrasonic irradiation was investigated. The effects of operating parameters, such as ultrasonic power, persulfate concentration, APFO concentration, and initial media pH on APFO degradation were discussed. In the absence of persulfate, 35.5% of initial APFO in 46.4 μmol/L solution under ultrasound irradiation, was decomposed rapidly after 120 min with the defluorination ratio reaching 6.73%. In contrast, when 10 mmol/L persulfate was used, 51.2% of initial APFO (46.4 μmol/L) was decomposed and the defluorination ratio reached 11.15% within 120 min reaction time. Enhancement of the decomposition of APFO can be explained by acceleration of substrate decarboxylation, induced by sulfate radical anions formed from the persulfate during ultrasonic irradiation. The SO4(-•)/APFO reactions at the bubble-water interface appear to be the primary pathway for the sonochemical degradation of the perfluorinated surfactants. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Alanine synthesis from glyceraldehyde and ammonium ion in aqueous solution

    Science.gov (United States)

    Weber, A. L.

    1985-01-01

    The formation of alanine (ala) form C(14)-glyceraldehyde and ammonium phosphate in the presence or absence of a thiol is reported. At ambient temperature, ala synthesis was six times more rapid in the presence of 3-mercaptopropionic acid than in its absence (0.6 and 0.1 percent, respectively, after 60 days). Similarly, the presence of another thiol, N-acetylcysteinate, increased the production of ala, as well as of lactate. The reaction pathway of thiol-catalyzed synthesis of ala, with the lactic acid formed in a bypath, is suggested. In this, dehydration of glyceraldehyde is followed by the formation of hemithioacetal. In the presence of ammonia, an imine is formed, which eventually yields ala. This pathway is consistent with the observation that the rate ratio of ala/lactate remains constant throughout the process. The fact that the reaction takes place under anaerobic conditions in the presence of H2O and with the low concentrations of simple substrates and catalysts makes it an attractive model prebiotic reaction in the process of molecular evolution.

  8. Antibacterial Activity of Dental Cements Containing Quaternary Ammonium Polyethylenimine Nanoparticles

    International Nuclear Information System (INIS)

    Beyth, N.; Weiss, E.I.; Pilo, R.

    2012-01-01

    Glass ionomer cements (GICs) are commonly used for cementing full cast crown restorations. Regrettably, although the dental cements fill the gap between the tooth and the crown, bacterial micro leakage may occur, resulting in secondary caries. As micro leakage cannot be completely prevented, GCS possessing antibacterial properties are in demand. In the present study the antibacterial activity of insoluble, cross-linked quaternary ammonium polyethylenimine (Qp) nanoparticles incorporated at 1% w/w in two clinically available GCS were studied. The antibacterial activity was tested against Streptococcus mutans and Lactobacillus casei using the direct contact test (Dct) and the agar diffusion test (Ad). Using the direct contact test, antibacterial activity (P<0.05) was found in both tested GICs with incorporated QPEI nanoparticles, the effect lasting for at least one month. However, the ADT showed no inhibition halo in the test bacteria, indicating that the antimicrobial nanoparticles do not diffuse into the agar. The results show that the incorporation of QPEI nanoparticles in glass ionomer cements has a long-lasting antibacterial effect against Streptococcus mutans and Lactobacillus casei. Changing the antibacterial properties of glass ionomer cements by incorporating QPEI antibacterial nanoparticles may prolong the clinical performance of dental crowns.

  9. Coloring Jupiter's clouds: Radiolysis of ammonium hydrosulfide (NH4SH)

    Science.gov (United States)

    Loeffler, Mark J.; Hudson, Reggie L.

    2018-03-01

    Here we present our recent studies on the color and spectral reflectance changes induced by ∼0.9 MeV proton irradiation of ammonium hydrosulfide, NH4SH, a compound predicted to be an important tropospheric cloud component of Jupiter and other giant planets. Ultraviolet-visible spectroscopy was used to observe and identify reaction products in the ice sample and digital photography was used to document the corresponding color changes at 10-160 K. Our experiments clearly show that the resulting color of the sample depends not only on the irradiation dose but also the irradiation temperature. Furthermore, unlike in our most recent studies of irradiation of NH4SH at 120 K, which showed that higher irradiation doses caused the sample to appear green, the lower temperature studies now show that the sample becomes red after irradiation. However, comparison of these lower temperature spectra over the entire spectral range observed by HST shows that even though the color and spectrum resemble the color and spectrum of the GRS, there is still enough difference to suggest that another component may be needed to adequately fit spectra of the GRS and other red regions of Jupiter's clouds. Regardless, the presence of NH4SH in the atmosphere of Jupiter and other gas giants, combined with this compound's clear alteration via radiolysis, suggests that its contribution to the ultraviolet-visible spectra of any of these object's clouds is significant.

  10. Anaerobic Ammonium-Oxidizing Bacteria in Cow Manure Composting.

    Science.gov (United States)

    Wang, Tingting; Cheng, Lijun; Zhang, Wenhao; Xu, Xiuhong; Meng, Qingxin; Sun, Xuewei; Liu, Huajing; Li, Hongtao; Sun, Yu

    2017-07-28

    Composting is widely used to transform waste into valuable agricultural organic fertilizer. Anaerobic ammonium-oxidizing (anammox) bacteria play an important role in the global nitrogen cycle, but their role in composting remains poorly understood. In the present study, the community structure, diversity, and abundance of anammox bacteria were analyzed using cloning and sequencing methods by targeting the 16S rRNA gene and the hydrazine oxidase gene ( hzo ) in samples isolated from compost produced from cow manure and rice straw. A total of 25 operational taxonomic units were classified based on 16S rRNA gene clone libraries, and 14 operational taxonomic units were classified based on hzo gene clone libraries. The phylogenetic tree analysis of the 16S rRNA gene and deduced HZO protein sequences from the corresponding encoding genes indicated that the majority of the obtained clones were related to the known anammox bacteria Candidatus "Brocadia," Candidatus "Kuenenia," and Candidatus "Scalindua." The abundances of anammox bacteria were determined by quantitative PCR, and between 2.13 × 10 5 and 1.15 × 10 6 16S rRNA gene copies per gram of compost were found. This study provides the first demonstration of the existence of anammox bacteria with limited diversity in cow manure composting.

  11. Absorption of ammonium sulphate 15N by coffee plants

    International Nuclear Information System (INIS)

    Fenilli, Tatiele Anete Bergamo; Reichardt, Klaus; Bacchi, Osny Oliveira Santos; Trivelin, Paulo Cesar Ocheuze; Dourado Neto, Durval

    2005-01-01

    The objective of this study was to quantify the absorption of ammonium sulphate 15 N by coffee plants. Treatments consisted of five sub-plots of 9 plants, of which the three central ones received 280 kg ha -1 of 15 N, applied at four times: 1/4 on 01 Set 03; 1/4 on 03 Nov 03; 1/4 on 15 Dec 03 and 1/4 on 30 Jan 04. The isotopic enrichment was 2,072 ± 0,001 atom % 15 N. The dry matter of the shoot was evaluated every 60 days, using one plant per replicate, collected outside the sub-plot. They were as similar as possible to the labeled plants, which were used only for isotopic and Total N analysis, after being dried at 65 deg C until constant weight. At harvest, plants had absorbed 42,88% of the fertilizer N. Leaves accumulated the largest amount of fertilizer N, and were also the compartments that received most N from other parts of the plant. The following partition of the fertilizer N was found at harvest: 23.01% in young leaves, 6.23% in old leaves, 4,46% in stem, 3.46% in fruits, 3.10% in young branches and 2.63% in old branches. (author)

  12. Ammonium nickel sulfate hexahydrate crystal: a new ultraviolet light filter

    International Nuclear Information System (INIS)

    Su Genbo; Zhuang Xinxin; He Youping; Li Zhengdong; Wang Guofu

    2002-01-01

    We propounded and grew a new crystal material of ammonium nickel sulfate hexahydrate (ANSH) for an ultraviolet light filter. The crystal structure of ANSH was solved by x-ray diffraction method and the empirical formula of the title compound is (NH 4 ) 2 Ni(SO 4 ) 2 c6H 2 O. The ANSH crystal belongs to the monoclinic space group P2 1 /C, a = 6.2351 A, b = 12.451(3) A, c = 9.1798(18) A, β = 106.88(3)deg , v = 681.9(2) A 3 , z = 2 and D c = 1.924 g cm -3 . The deep-green ANSH single crystal with a dimension of 20.5x28x15 mm 3 has been grown by the cooling solution method. Thermo-gravimetry analysis showed that the dehydration temperature of the ANSH crystal is above 96.06 deg. C, which is much higher than that of commercially available nickel sulfate hexahydrate (NSH) crystals. The optical transmission character of the ANSH crystal is discontinuous in the range from ultraviolet (UV) to near IR wavelengths, and has several transmission peaks at 250 nm, 500 nm, 875 nm and 1425 nm, respectively. The UV transmission peak (250 nm) especially has high transmission efficiency and a narrow spectrum band-width. The relationship between the structure and the optical transmission property is further discussed

  13. Crystallization of Chicken Egg-White Lysozyme from Ammonium Sulfate

    Science.gov (United States)

    Forsythe, Elizabeth L.; Snell, Edward H.; Pusey, Marc L.

    1997-01-01

    Chicken egg-white lysozyme was crystallized from ammonium sulfate over the pH range 4.0-7.8, with protein concentrations from 100 to 150 mg/ml. Crystals were obtained by vapor-diffusion or batch-crystallization methods. The protein crystallized in two morphologies with an apparent morphology dependence on temperature and protein concentration. In general, tetragonal crystals could be grown by lowering the protein concentration or temperature. Increasing the temperature or protein concentration resulted in the growth of orthorhombic crystals. Representative crystals of each morphology were selected for X-ray analysis. The tetragonal crystals belonged to the P4(sub 3)2(sub 1)2 space group with crystals grown at ph 4.4 having unit-cell dimensions of a = b = 78.7 1, c=38.6 A and diffracting to beyond 2.0 A. The orthorhombic crystals, grown at pH 4.8, were of space group P2(sub 1)2(sub 1)2 and had unit-cell dimensions of a = 30.51, b = 56.51 and c = 73.62 A.

  14. Electrochemical properties of quaternary ammonium salts for electrochemical capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Ue, Makoto; Takeda, Masayuki; Takehara, Masahiro; Mori, Shoichiro [Mitsubishi Chemical Corp., Inashiki, Ibaraki (Japan). Tsukuba Research Center

    1997-08-01

    The limiting reduction and oxidation potentials and electrolytic conductivities of new quaternary ammonium salts were examined for electrochemical capacitor applications, whose anions have already been tested as lithium salts for lithium battery applications. The anodic stability was in the following order BR{sub 4}{sup {minus}} < ClO{sub 4}{sup {minus}} {le} CF{sub 3}SO{sub 3}{sup {minus}} < (CF{sub 3}SO{sub 2}){sub 2}N{sup {minus}} {le} C{sub 4}F{sub 9}SO{sub 3}{sup {minus}} < BF{sub 4}{sup {minus}} < PF{sub 6}{sup {minus}} {le} AsF{sub 6}{sup {minus}} < SbF{sub 6}{sup {minus}}. The electrolytic conductivities of Me{sub 4{minus}n}Et{sub n}N(CF{sub 3}SO{sub 2}){sub 2}N (n = 0--4) were examined in comparison with Me{sub 4{minus}n}Et{sub n}NBF{sub 4} counterparts. These imide salts showed good solubility, relatively high conductivity, and anodic stability in propylene carbonate. Et{sub 4}N(CF{sub 3}SO{sub 2}){sub 2}N was found to be a good supporting salt for low permittivity organic solvents, and it afforded a highly conductive electrolyte system based on the ethylene carbonate-dimethyl carbonate mixed solvent, which is useful for electrochemical capacitor applications.

  15. Antibacterial Activity of Dental Cements Containing Quaternary Ammonium Polyethylenimine Nanoparticles

    Directory of Open Access Journals (Sweden)

    Nurit Beyth

    2012-01-01

    Full Text Available Glass ionomer cements (GICs are commonly used for cementing full cast crown restorations. Regrettably, although the dental cements fill the gap between the tooth and the crown, bacterial microleakage may occur, resulting in secondary caries. As microleakage cannot be completely prevented, GICs possessing antibacterial properties are in demand. In the present study the antibacterial activity of insoluble, cross-linked quaternary ammonium polyethylenimine (QPEI nanoparticles incorporated at 1% w/w in two clinically available GICs were studied. The antibacterial activity was tested against Streptococcus mutans and Lactobacillus casei using the direct contact test (DCT and the agar diffusion test (ADT. Using the direct contact test, antibacterial activity (<0.05 was found in both tested GICs with incorporated QPEI nanoparticles, the effect lasting for at least one month. However, the ADT showed no inhibition halo in the test bacteria, indicating that the antimicrobial nanoparticles do not diffuse into the agar. The results show that the incorporation of QPEI nanoparticles in glass ionomer cements has a long-lasting antibacterial effect against Streptococcus mutans and Lactobacillus casei. Changing the antibacterial properties of glass ionomer cements by incorporating QPEI antibacterial nanoparticles may prolong the clinical performance of dental crowns.

  16. Formation rate of ammonium nitrate in the off-gas line of SRAT and SME in DWPF

    International Nuclear Information System (INIS)

    Lee, L.

    1992-01-01

    A mathematical model for the formation rate of ammonium nitrate in the off-gas line of the Sludge Receipt and Adjustment Tank (SRAT) and the Slurry Mixed Evaporator (SME) in DWPF has been developed. The formation rate of ammonium nitrate in the off-gas line depends on pH, temperature, volume and total concentration of ammonia and ammonium ion. Based on a typical SRAT and SME cycle in DWPF, this model predicts the SRAT contributes about 50 lbs of ammonium nitrate while SME contributes about 60 lbs of ammonium nitrate to the off-gas line

  17. Precipitation reactions in austenitic stainless steels

    International Nuclear Information System (INIS)

    Hoch, M.; Yung-Shih Chen

    1979-01-01

    The precipitation reactions for commercial austenitic stainless steels (AISI type 347, 321, 316, 316L, 304 and 304L) and Ti-modified AISI type 316 SS were studied in the temperature range of 750 0 C-1350 0 C. Specimens were held at the temperature for 15 to 25 hours to ensure that equilibrium conditions were reached and followed by a water quench to prevent further precipitation reactions during cooling process. The precipitates were extracted from bulk specimens by anodic dissolution and identified by x-ray diffraction analysis. In Ti-stabilized 321 SS, large TiN and Ti 2 S (Ti 4 C 2 S2) precipitates were present in solution treated and subsequent annealed specimens. Small TiC precipitates were present in specimens annealed below 1150 0 C. The M 23 C 6 precipitates were found to be present after annealing at 850 0 C for 25 hours. The amount of M 23 C 6 was found to increase with decreased Ti content as shown in the Ti-motified 316 SS. In Nb-stabilized 347 SS, Nb(CN) precipitates were present in solution treated as well as annealed specimens. The M 23 C 6 precipitates were detected at an annealing temperature of 1050 0 C, which is higher than the precipitation temperature detected in 321 SS. Thermodynamic calculations were carried out to obtain the temperature where precipitation starts, and the temperatures where 50, 90 and 99% of the precipitates should be formed. The experimental results are in very good agreement with the calculations. (orig.) [de

  18. Selective extraction of vanadium from the APV-precipitated waste water

    Science.gov (United States)

    Li, Cui; Li, Hong-Yi; Tu, Chun-Bin; Zhang, Tao; Fang, Hai-Xing; Xie, Bing

    In the process of precipitating ammonium polyvanadate (APV) to produce vanadium pentoxide in Pan-steel in China, rest waste water usually contains about 24 333mg/L V(V), 2 100g/L Cr(VI),20 500mg/L Si(IV) and 20 100g/L Na2SO4. In order to recover valuable and also toxic metal ions contained in the waste water, effective extraction method of using anion exchange resin was realized to extract Vanadium selectively, leading to effective separation between vanadium and chromium. To ensure vanadium was absorbed by the resin, V(V) and Cr(VI) were reduced to V(IV) and Cr(III) by NaHSO3, respectively, and then V(IV) was oxidized by H2O2 to V(V) anions. Effects of temperature, solution pH, concentration of ions and absorbing time on vanadium absorption rate were investigated. Chromium was precipitated from rest solution while vanadium was eluted from resin by NaOH solution and then precipitated. Results showed that vanadium recovery of 73% could be obtained in optimized condition. The resin could be regenerated by 3% hydrochloric acid, which indicated the recyclability of the resin and thus low cost of this established method.

  19. Discontinuous precipitation in copper base alloys

    Indian Academy of Sciences (India)

    Discontinuous precipitation (DP) is associated with grain boundary migration in the wake of which alternate plates of the precipitate and the depleted matrix form. Some copper base alloys show ... 100 > ± 0.1, DP is observed. This criterion points to diffusional coherency strain theory to be the operative mechanism for DP.

  20. Meteorological features associated with unprecedented precipitation ...

    Indian Academy of Sciences (India)

    Unprecedented precipitation along with heavy falls occurred over many parts of India from 28th February to 2nd March 2015. Many of the stations of northwest and central India received an all time high 24 hr cumulative precipitation of March during this period. Even the national capital, New Delhi, broke all the previous ...

  1. Calcium carbonate precipitation by different bacterial strains ...

    African Journals Online (AJOL)

    Bacteria are capable of performing metabolic activities which thereby promote precipitation of calcium carbonate in the form of calcite. In this study, it is shown that microbial mineral precipitation was a result of metabolic activities of some specific microorganisms. Concrete microorganisms were used to improve the overall ...

  2. Discontinuous precipitation in copper base alloys

    Indian Academy of Sciences (India)

    Administrator

    Discontinuous precipitation (DP) is associated with grain boundary migration in the wake of which alternate plates of the precipitate and the ... force, the fundamental problem for the driving force for grain boundary (GB) migration, exists. .... systems (Germany: Springer Verlag). Kashyap K T, Ramachandra C, Sujatha M and ...

  3. Study of asphaltene precipitation by Calorimetry

    DEFF Research Database (Denmark)

    Verdier, Sylvain Charles Roland; Plantier, Frédéric; Bessières, David

    2007-01-01

    Can calorimetry bring new input to the Current understanding of asphaltene precipitation? In this work, two types of precipitation were studied by means of calorimetry: addition of n-heptane into asphaltene solutions and temperature/pressure variations on a recombined live oil. The first series...

  4. Isotope fingerprinting of precipitation associated with western ...

    Indian Academy of Sciences (India)

    Ghulam Jeelani

    2017-11-22

    Nov 22, 2017 ... The isotopic signa- ture of precipitation provides valuable information about vapour source and atmospheric circulation pattern. In the modern environment, the isotopic composition of precipitation provides a conser- vative tracer for the origin, phase transitions, and transport paths of water (Dansgaard 1964 ...

  5. Investigation of Asphaltene Precipitation at Elevated Temperature

    DEFF Research Database (Denmark)

    Andersen, Simon Ivar; Lindeloff, Niels; Stenby, Erling Halfdan

    1998-01-01

    In order to obtain quantitative data on the asphaltene precipitation induced by the addition of n-alkane (heptane) at temperatures above the normal boiling point of the precipitant, a high temperature/high pressure filtration apparatus has been constructed. Oil and alkane are mixed at the appropr...

  6. Projections of precipitation, air temperature and potential ...

    African Journals Online (AJOL)

    mabouelhaggag

    Precipitation and air temperature records from 6 sites in Rwanda in the period from 1964 to 2010 are used for past/present climate assessment. Future climate projections (2010-2099) based on 3 general circulation models and 2 emission scenarios (A2 and B1) are used for climate projections. Precipitation, air temperature ...

  7. Application of probabilistic precipitation forecasts from a ...

    African Journals Online (AJOL)

    2014-02-14

    Feb 14, 2014 ... Application of probabilistic precipitation forecasts from a deterministic model ... aim of this paper is to investigate the increase in the lead-time of flash flood warnings of the SAFFG using probabilistic precipitation forecasts ... The procedure is applied to a real flash flood event and the ensemble-based.

  8. Discontinuous precipitation in copper base alloys

    Indian Academy of Sciences (India)

    Discontinuous precipitation (DP) is associated with grain boundary migration in the wake of which alternate plates of the precipitate and the depleted matrix form. Some copper base alloys show DP while others do not. In this paper the misfit strain parameter, , has been calculated and predicted that if 100 > ± 0.1, DP is ...

  9. Effect of Sodium Sulfate, Ammonium Chloride, Ammonium Nitrate, and Salt Mixtures on Aqueous Phase Partitioning of Organic Compounds.

    Science.gov (United States)

    Wang, Chen; Lei, Ying Duan; Wania, Frank

    2016-12-06

    Dissolved inorganic salts influence the partitioning of organic compounds into the aqueous phase. This influence is especially significant in atmospheric aerosol, which usually contains large amounts of ions, including sodium, ammonium, chloride, sulfate, and nitrate. However, empirical data on this salt effect are very sparse. Here, the partitioning of numerous organic compounds into solutions of Na 2 SO 4 , NH 4 Cl, and NH 4 NO 3 was measured and compared with existing data for NaCl and (NH 4 ) 2 SO 4 . Salt mixtures were also tested to establish whether the salt effect is additive. In general, the salt effect showed a decreasing trend of Na 2 SO 4 > (NH) 2 SO 4 > NaCl > NH 4 Cl > NH 4 NO 3 for the studied organic compounds, implying the following relative strength of the salt effect of individual anions: SO 4 2- > Cl - > NO 3 - and of cations: Na + > NH 4 + . The salt effect of different salts is moderately correlated. Predictive models for the salt effect were developed based on the experimental data. The experimental data indicate that the salt effect of mixtures may not be entirely additive. However, the deviation from additivity, if it exists, is small. Data of very high quality are required to establish whether the effect of constituent ions or salts is additive or not.

  10. Physicochemical study of the alteration surface of concrete exposed to ammonium salts

    International Nuclear Information System (INIS)

    Jauberthie, Raoul; Rendell, Frank

    2003-01-01

    The storage of chemicals in concrete silos often presents durability problems due to chemical attack, the high concentration encountered inevitably causes severe conditions. The aim of this paper is to examine the physicochemical changes that occur in concrete exposed to ammonium salts, notably ammonium sulphate and nitrate, which are noted for their aggressivity. The modification to mortar surfaces is examined with X-ray diffraction (XRD) and with SEM. Mortar immersed in ammonium sulphate is covered with gypsum needle-like crystals and undergoes rapid cracking when removed from the solution and washed. In the case of mortars immersed in ammonium nitrate solutions, there is rapid decalcification, accompanied by strength loss, due to the solubilization of calcium. It is also observed that the mortar surface is covered with rhombic calcite, which is attributed to the reaction between liberated calcium and CO 2 in the water

  11. [Effect of ammonium sulfate aerosol on the photochemical reaction of toluene/ NO(x)/air mixture].

    Science.gov (United States)

    Wu, Shan; Hao, Ji-Ming; Lü, Zi-Feng; Zhao, Zhe; Li, Jun-Hua

    2007-06-01

    The effect of ammonium sulfate aerosol on the photochemical reaction of toluene/NO(x)/air mixture was evaluated with Tsinghua Smog Chamber facility. The results indicate that the presence of concentrated preexisting ammonium sulfate aerosol shortens the time to reach maximum PM (particle matter) concentration and increases the aerosol yield of toluene. And under the presence of high concentrated ammonium sulfate aerosol seed, the concentration of aerosol does not have significant effects on NO(x), NO and O3 variation, but affects the formation of secondary organic aerosol (SOA). The SOA yield increases with the increasing initial ammonium sulfate seed concentration (< 160 microg x m(-3)). From the minimum 7.2% to the maximum 11.7%, the percentage increase of SOA yield is more than 60%.

  12. Contribution to the use in analysis of ammonium phosphomolybdate- separation of radio-caesium in solution

    International Nuclear Information System (INIS)

    Scheidhauer, J.; Chabidon, M.; Ordinaire, L.

    1964-01-01

    The use in analysis of ammonium phosphomolybdate has been studied for the separation of barium from caesium 137. The cases have been studied of small and medium-sized volumes, and of large volumes of about 100 litres. (authors) [fr

  13. Effects of ammonium and nitrate on mycorrhizal seedlings of Pinus sylvestris.

    NARCIS (Netherlands)

    Termorshuizen, A.J.; Ket, P.C.

    1991-01-01

    The effects of ammonium sulphate and sodium nitrate on Pinus sylvestris seedlings inoculated with Paxillus involutus and Suillus bovinus were investigated. Weekly fertilization (26 weeks) positively affected the plant dry weight, but inhibited the mycorrhizal formation and decreased the root

  14. Microbially Induced Calcite Precipitation Employing Environmental Isolates

    Directory of Open Access Journals (Sweden)

    Gunjo Kim

    2016-06-01

    Full Text Available In this study, five microbes were employed to precipitate calcite in cohesionless soils. Four microbes were selected from calcite-precipitating microbes isolated from calcareous sand and limestone cave soils, with Sporosarcina pasteurii ATCC 11859 (standard strain used as a control. Urease activities of the four microbes were higher than that of S. pasteurii. The microbes and urea–CaCl2 medium were injected at least four times into cohesionless soils of two different relative densities (60% and 80%, and the amount of calcite precipitation was measured. It was found that the relative density of cohesionless soils significantly affects the amount of calcite precipitation and that there is a weak correlation between urease activity and calcite precipitation.

  15. Global precipitations and climate change. Proceedings

    International Nuclear Information System (INIS)

    Desbois, M.; Desalmand, F.

    1994-01-01

    The workshop reviewed the present status of knowledge concerning the past and present evolution of the distribution of precipitations at global scale, related to climate evolution at different time scales. This review was intended to assess the availability and quality of data which could help, through validation and initialization of model studies, to improve our understanding of the processes determining these precipitation changes. On another hand, the modelling specialists presented their actual use of precipitation data. Exchanges of views between the modelling and observing communities were thus made possible, leading to a set of recommendations for future studies. Sessions were then devoted to specific themes: 1) Paleoclimatology, 2) data collection, history and statistics, programmes, 3) methodologies and accuracy of large scale estimation of precipitation from conventional data, 4) estimation of precipitation from satellite data, 5) modelling studies. (orig.)

  16. Research of chemical structure of atmospheric precipitation

    International Nuclear Information System (INIS)

    Korenyak, D.

    2001-01-01

    The structure of atmospheric precipitation changes in its passing through the air medium. Thus, the atmospheric precipitation is one of the ecological factors, acting regularly. The research of chemical structure of atmospheric precipitation is closely connected with the problems of turnover of elements, with sanitary - ecological conditions of regions, with the matters of agricultural equipment and of salt balance of the soils. In paper the author for the first time represents the data on chemical structure of precipitation in the town. The data of chemical analysis of 18 samples are given. Obtained results permitted, to a certain extent, to determine the mechanisms of formation of atmospheric precipitation in the region investigated and its genesis. (authors)

  17. Interactions of Iron and Ammonium on N-Uptake in the Southern Ocean South of Australia

    Science.gov (United States)

    Savoye, N.; Dehairs, F.; Elskens, M.; Sedwick, P.; Hutchins, D.

    2002-12-01

    The ability to model new production is important for prognostic studies of the global carbon cycle, as new production represents the "exportable" fraction of carbon from the photic zone. Here we consider the effects of ammonium and iron availability on algal nitrogen uptake and the f-ratio (the relative fraction of new vs. regenerated production) in the Southern Ocean. To investigate the individual and combined effects of ammonium and iron availability on nitrogen uptake in natural plankton assemblages, we conducted shipboard experiments at three locations between Australia and Antarctica during austral spring (CLIVAR SR3 transect, November 2001): the Subantarctic Zone (SAZ), the Polar Front Zone (PFZ) and the Antarctic Zone-South (AZ-S). Here ambient surface-water dissolved iron levels were 0.26, 0.14 and 0.11 nM, respectively. Cleanly-collected seawater was divided into two incubation treatments: one with added iron (+1.8 nM) and one without (control). After incubation for ca. one week, we measured the uptake of nitrate, ammonium and urea, in both the control and iron-enriched treatments, both with and without added ammonium (0.2 to 0.9 æM). Iron enrichment enhanced nitrate (4-7x), ammonium (2x) and urea (2-3x) uptake rates, with a concomitant increase in the f-ratio of about 1.4x. Overall, ammonium additions resulted in enhanced ammonium uptake rates and lowered nitrate uptake rates, while there was no clear effect on the uptake of urea. Consequently, ammonium addition decreased the f-ratio in both Fe-enriched and non-Fe-enriched experiments. These results are in agreement with previous field observations from the SAZ, and suggest that there is a synergistic interaction between iron and ammonium in regulating community nitrogen uptake and the f-ratio. Iron availability increases the f-ratio and hence new production, implying enhanced particle flux from the surface ocean to the mesopelagic zone. In contrast, ammonium addition leads to decreases in nitrate use

  18. Phosphate limitation in biological rapid sand filters used to remove ammonium from drinking water

    DEFF Research Database (Denmark)

    Lee, Carson Odell; Albrechtsen, Hans-Jørgen; Smets, Barth F.

    2013-01-01

    Removing ammonium from drinking water is important for maintaining biological stability in distribution systems. This is especially important in regions that do not use disinfectants in the treatment process or keep a disinfectant residual in the distribution system. Problems with nitrification can...... the total number of ammonium oxidizing bacteria in the column. © 2013 American Water Works Association AWWA WQTC Conference Proceedings All Rights Reserved....

  19. Ammonium nitrate and iron nutrition effects on some nitrogen assimilation enzymes and metabolites in Spirulina platensis.

    Science.gov (United States)

    Esen, Merve; Ozturk Urek, Raziye

    2015-01-01

    The effect of various concentrations of ammonium nitrate (5-60 mM), an economical nitrogen source, on the growth, nitrate-ammonium uptake rates, production of some pigments and metabolites, and some nitrogen assimilation enzymes such as nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), and glutamate synthase (GOGAT) in Spirulina platensis (Gamont) Geitler was investigated. Ten millimolars of ammonium nitrate stimulated the growth, production of pigments and the other metabolites, and enzyme activities, whereas 30 and 60 mM ammonium nitrate caused inhibition. In the presence of 10 mM ammonium nitrate, different concentrations of iron were tried in the growth media of S. platensis. After achieving the best growth, levels of metabolite and pigment production, and enzyme activities in the presence of 10 mM ammonium nitrate as a nitrogen source, different iron concentrations (10-100 µM) were tried in the growth medium of S. platensis. The highest growth, pigment and metabolite levels, and enzyme activities were determined in the medium containing 50 µM iron and 10 mM ammonium nitrate. In this optimum condition, the highest dry biomass level, chlorophyll a, and pyruvate contents were obtained as 55.42 ± 3.8 mg mL(-1) , 93.114 ± 7.9 µg g(-1) , and 212.5 ± 18.7 µg g(-1) , respectively. The highest NR, NiR, GS, and GOGAT activities were 67.16 ± 5.1, 777.92 ± 52, 0.141 ± 0.01, and 44.45 ± 3.6, respectively. Additionally, 10 mM ammonium nitrate is an economical and efficient nitrogen source for nitrogen assimilation of S. platensis, and 50 µM iron is optimum for the growth of S. platensis. © 2014 International Union of Biochemistry and Molecular Biology, Inc.

  20. Advances in methods for detection of anaerobic ammonium oxidizing (anammox) bacteria

    OpenAIRE

    Li, Meng; Gu, Ji-Dong

    2011-01-01

    Anaerobic ammonium oxidation (anammox), the biochemical process oxidizing ammonium into dinitrogen gas using nitrite as an electron acceptor, has only been recognized for its significant role in the global nitrogen cycle not long ago, and its ubiquitous distribution in a wide range of environments has changed our knowledge about the contributors to the global nitrogen cycle. Currently, several groups of methods are used in detection of anammox bacteria based on their physiological and biochem...

  1. Glyphosate and glufosinate-ammonium runoff from a corn-growing area in Italy

    OpenAIRE

    Screpanti , Claudio; Accinelli , Cesare; Vicari , Alberto; Catizone , Pietro

    2005-01-01

    International audience; The main objective of this experiment was to estimate field-scale runoff losses of glyphosate and glufosinate-ammonium under natural rainfall conditions. Investigations were carried out at the Runoff Monitoring Station of the University of Bologna (Italy). Glyphosate and glufosinate-ammonium were applied as pre-emergence herbicides on 350-m2 field plots characterized by a uniform slope of 15%. Field plots were cultivated with corn. The persistence and sorption isotherm...

  2. Field Dissipation and Storage Stability of Glufosinate Ammonium and Its Metabolites in Soil

    Directory of Open Access Journals (Sweden)

    Yun Zhang

    2014-01-01

    Full Text Available A simple analytical method was developed to measure concentrations of glufosinate ammonium and its metabolites, 3-methylphosphinico-propionic acid (MPP and 2-methylphosphinico-acetic acid (MPA, in field soil samples. To determine the minimum quantification limit, samples were spiked at different levels (0.1, 0.5, and 1.0 mg/kg. Soil samples were extracted with ammonium hydroxide solution 5% (v/v, concentrated, and reacted with trimethyl orthoacetate (TMOA in the presence of acetic acid for derivatization. The derivatives were quantified by gas chromatography (GC using a flame photometric detector (FPD. The linear correlation coefficients of glufosinate ammonium, MPP, and MPA in soil were 0.991, 0.999, and 0.999, respectively. The recoveries of this method for glufosinate ammonium, MPP, and MPA in soil were 77.2–95.5%, 98.3–100.3%, and 99.3–99.6% with relative standard deviations (RSD of 1.8–4.1%, 0.4–1.4%, and 1.3–2.0%, respectively. Glufosinate ammonium dissipated rapidly in soil to MPA in hours and gradually degraded to MPP. The half-life of glufosinate ammonium degradation in soil was 2.30–2.93 days in an open field. In soil samples stored at −20°C glufosinate ammonium was stable for two months. The results of this study should provide guidance for the safe application of the herbicide glufosinate ammonium to agricultural products and the environment.

  3. Nitrogen loss in Brachiaria decumbens after application of glyphosate or glufosinate-ammonium

    OpenAIRE

    Damin,Virginia; Franco,Henrique Coutinho Junqueira; Moraes,Milton Ferreira; Franco,Ademir; Trivelin,Paulo Cesar Ocheuze

    2008-01-01

    Nitrogen losses from the soil-plant system may be influenced by herbicide applications. In order to evaluate N loss in brachiaria (Brachiaria decumbens) after application of the herbicides glyphosate and glufosinate-ammonium, an experiment was carried out in a greenhouse as a completely randomized design, with three treatments and six replicates. Treatments were as follows: i) desiccation of brachiaria-plants with glyphosate; ii) desiccation of brachiaria-plants with glufosinate-ammonium; and...

  4. Field Dissipation and Storage Stability of Glufosinate Ammonium and Its Metabolites in Soil

    Science.gov (United States)

    Zhang, Yun; Wang, Kai; Wu, Junxue; Zhang, Hongyan

    2014-01-01

    A simple analytical method was developed to measure concentrations of glufosinate ammonium and its metabolites, 3-methylphosphinico-propionic acid (MPP) and 2-methylphosphinico-acetic acid (MPA), in field soil samples. To determine the minimum quantification limit, samples were spiked at different levels (0.1, 0.5, and 1.0 mg/kg). Soil samples were extracted with ammonium hydroxide solution 5% (v/v), concentrated, and reacted with trimethyl orthoacetate (TMOA) in the presence of acetic acid for derivatization. The derivatives were quantified by gas chromatography (GC) using a flame photometric detector (FPD). The linear correlation coefficients of glufosinate ammonium, MPP, and MPA in soil were 0.991, 0.999, and 0.999, respectively. The recoveries of this method for glufosinate ammonium, MPP, and MPA in soil were 77.2–95.5%, 98.3–100.3%, and 99.3–99.6% with relative standard deviations (RSD) of 1.8–4.1%, 0.4–1.4%, and 1.3–2.0%, respectively. Glufosinate ammonium dissipated rapidly in soil to MPA in hours and gradually degraded to MPP. The half-life of glufosinate ammonium degradation in soil was 2.30–2.93 days in an open field. In soil samples stored at −20°C glufosinate ammonium was stable for two months. The results of this study should provide guidance for the safe application of the herbicide glufosinate ammonium to agricultural products and the environment. PMID:25374604

  5. Giant-Planet Chemistry: Ammonium Hydrosulfide (NH4SH), Its IR Spectra and Thermal and Radiolytic Stabilities

    Science.gov (United States)

    Loeffler, Mark J.; Hudson, Reggie L.; Chanover, Nancy J.; Simon, Amy A.

    2015-01-01

    Here we present our recent studies of proton-irradiated and unirradiated ammonium hydrosulfide, NH4SH, a compound predicted to be an important tropospheric cloud component of Jupiter and other giant planets. We irradiated both crystalline and amorphous NH4SH at 10-160 K and used IR spectroscopy to observe and identify reaction products in the ice, specifically NH3 and long-chained sulfur-containing ions. Crystalline NH4SH was amorphized during irradiation at all temperatures studied with the rate being the fastest at the lowest temperatures. Irradiation of amorphous NH4SH at approximately 10-75 K showed that 60-80% of the NH4 + remained when equilibrium was reached, and that NH4SH destruction rates were relatively constant within this temperature range. Irradiations at higher temperatures produced different dose dependence and were accompanied by pressure outbursts that, in some cases, fractured the ice. The thermal stability of irradiated NH4SH was found to be greater than that of unirradiated NH4SH, suggesting that an irradiated giant-planet cloud precipitate can exist at temperatures and altitudes not previously considered.

  6. Precipitation of Continental Origin over South America

    Science.gov (United States)

    Martinez-Agudelo, J. A.; Dominguez, F.

    2012-12-01

    The Amazon forest receives high amounts of moisture from the tropical Atlantic. A significant part of this moisture is returned back to the atmosphere by the forest, and further redistributed to the rest of the continent by the meridional flow imposed by the Andes. Thus, the land-atmosphere interaction between the Amazon forest and the large-scale flow affects not only the forest itself but also the downstream regions. We develop a method to quantify the precipitation of continental origin over South America, and identify the contribution that selected source regions make to continental precipitation. The average annual cycle of precipitation of continental origin for the five-year period 2000-2004 shows a band of high values aligned along the northwest-southeast direction, from southern Peru to northeastern Argentina. The lowest values of precipitation of continental origin occur upstream, over the northeastern coast of South America. Precipitation that originates as moisture from the Amazon forest shows maximum values over the western side of the Amazon, east of the Andes, especially over southern Peru. The Amazon forest also contributes to precipitation over La Plata River Basin (LPRB) and the Pacific coast of Colombia. During its dry season, up to 29.3% of the precipitation over LPRB originates as moisture from the Amazon forest. Throughout the year, the contributions to precipitation over LPRB by the Amazon forest and LPRB (recycled precipitation) are in the same range, but out of phase. The average contribution of the rest of the continent to precipitation over LPRB is smaller but of the same order as that of the Amazon and LPRB.

  7. Probabilistic Precipitation Estimation with a Satellite Product

    Directory of Open Access Journals (Sweden)

    Nir Y. Krakauer

    2015-04-01

    Full Text Available Satellite-based precipitation products have been shown to represent precipitation well over Nepal at monthly resolution, compared to ground-based stations. Here, we extend our analysis to the daily and subdaily timescales, which are relevant for mapping the hazards caused by storms as well as drought. We compared the Tropical Rainfall Measuring Mission (TRMM Multi-satellite Precipitation Analysis (TMPA 3B42RT product with individual stations and with the gridded APHRODITE product to evaluate its ability to retrieve different precipitation intensities. We find that 3B42RT, which is freely available in near real time, has reasonable correspondence with ground-based precipitation products on a daily timescale; rank correlation coefficients approach 0.6, almost as high as the retrospectively calibrated TMPA 3B42 product. We also find that higher-quality ground and satellite precipitation observations improve the correspondence between the two on the daily timescale, suggesting opportunities for improvement in satellite-based monitoring technology. Correlation of 3B42RT and 3B42 with station observations is lower on subdaily timescales, although the mean diurnal cycle of precipitation is roughly correct. We develop a probabilistic precipitation monitoring methodology that uses previous observations (climatology as well as 3B42RT as input to generate daily precipitation accumulation probability distributions at each 0.25° x 0.25° grid cell in Nepal and surrounding areas. We quantify the information gain associated with using 3B42RT in the probabilistic model instead of relying only on climatology and show that the quantitative precipitation estimates produced by this model are well calibrated compared to APHRODITE.

  8. Thermophysical properties of ammonium and hydroxylammonium protic ionic liquids

    International Nuclear Information System (INIS)

    Chhotaray, Pratap K.; Gardas, Ramesh L.

    2014-01-01

    Highlights: • Density, viscosity and sound velocity measured for five ammonium and hydroxylammonium based protic ionic liquids. • Experimental density and viscosity data estimated using Gardas and Coutinho model and Vogel–Tamman–Fulcher equation. • Effects of cation, anion and alkyl chain length on studied properties have been discussed. • The intermolecular interactions were analyzed on the basis of derived properties. - Abstract: In this work, five protic ionic liquids having propylammonium, 3-hydroxy propylammonium as cations and formate, acetate, trifluoroacetate as anions have been synthesized. Thermophysical properties such as density (ρ), viscosity (η) and sound velocity (u) have been measured at various temperatures ranging from (293.15 to 343.15) K at atmospheric pressure. The experimental density and viscosity were fitted with second order polynomial and Vogel–Tamman–Fulcher (VTF) equations, respectively. Also experimental densities were correlated with the estimated density proposed by Gardas and Coutinho model. The coefficient of thermal expansion (α) and isentropic compressibility (β s ) values have been calculated from the experimental density and sound velocity data using empirical correlations. Lattice potential energy (U POT ) has been calculated to understand the strength of ionic interaction between the ions. Thermal decomposition temperature (T d ) and glass transition temperature (T g ) along with crystallization and melting point were investigated using TGA and DSC analysis, respectively. The effect of alkyl chain length and electronegative fluorine atoms on anionic fragment as well as hydroxyl substituent on cationic side chain in the protic ionic liquids has been discussed for studied properties. The effect of ΔpK a over the studied properties has also been analyzed

  9. Crystallization pathways of sulfate-nitrate-ammonium aerosol particles.

    Science.gov (United States)

    Schlenker, Julie C; Martin, Scot T

    2005-11-10

    Crystallization experiments are conducted for aerosol particles composed of aqueous mixtures of (NH(4))(2)SO(4)(aq) and NH(4)NO(3)(aq), (NH(4))(2)SO(4)(aq) and NH(4)HSO(4)(aq), and NH(4)NO(3)(aq) and NH(4)HSO(4)(aq). Depending on the aqueous composition, crystals of (NH(4))(2)SO(4)(s), (NH(4))(3)H(SO(4))(2)(s), NH(4)HSO(4)(s), NH(4)NO(3)(s), 2NH(4)NO(3) x (NH(4))(2)SO(4)(s), and 3NH(4)NO(3) x (NH(4))(2)SO(4)(s) are formed. Although particles of NH(4)NO(3)(aq) and NH(4)HSO(4)(aq) do not crystallize even at 1% relative humidity, additions of 0.05 mol fraction SO(4)(2-)(aq) or NO(3)(-)(aq) ions promote crystallization, respectively. 2NH(4)NO(3) x (NH(4))(2)SO(4)(s) and (NH(4))(3)H(SO(4))(2)(s) appear to serve as good heterogeneous nuclei for NH(4)NO(3)(s) and NH(4)HSO(4)(s), respectively. 2NH(4)NO(3) x (NH(4))(2)SO(4)(s) crystallizes over a greater range of aqueous compositions than 3NH(4)NO(3) x (NH(4))(2)SO(4)(s). An infrared aerosol spectrum is provided for each solid based upon a linear decomposition analysis of the recorded spectra. Small nonzero residuals occur in the analysis because aerosol spectra depend on particle morphology, which changes slightly across the range of compositions studied. In addition, several of the mixed compositions crystallize with residual aqueous water of up to 5% particle mass. We attribute this water content to enclosed water pockets. The results provide further insights into the nonlinear crystallization pathways of sulfate-nitrate-ammonium aerosol particles.

  10. Nitrogen loss from soil through anaerobic ammonium oxidation coupled to iron reduction

    Science.gov (United States)

    Yang, Wendy H.; Weber, Karrie A.; Silver, Whendee L.

    2012-08-01

    The oxidation of ammonium is a key step in the nitrogen cycle, regulating the production of nitrate, nitrous oxide and dinitrogen. In marine and freshwater ecosystems, anaerobic ammonium oxidation coupled to nitrite reduction, termed anammox, accounts for up to 67% of dinitrogen production. Dinitrogen production through anaerobic ammonium oxidation has not been observed in terrestrial ecosystems, but the anaerobic oxidation of ammonium to nitrite has been observed in wetland soils under iron-reducing conditions. Here, we incubate tropical upland soil slurries with isotopically labelled ammonium and iron(III) to assess the potential for anaerobic ammonium oxidation coupled to iron(III) reduction, otherwise known as Feammox, in these soils. We show that Feammox can produce dinitrogen, nitrite or nitrate in tropical upland soils. Direct dinitrogen production was the dominant Feammox pathway, short-circuiting the nitrogen cycle and resulting in ecosystem nitrogen losses. Rates were comparable to aerobic nitrification and to denitrification, the latter being the only other process known to produce dinitrogen in terrestrial ecosystems. We suggest that Feammox could fuel nitrogen losses in ecosystems rich in poorly crystalline iron minerals, with low or fluctuating redox conditions.

  11. Removal of ammonium from aqueous solutions using alkali-modified biochars

    Directory of Open Access Journals (Sweden)

    Zhigang Liu

    2016-10-01

    Full Text Available Biochars converted from agricultural residuals can effectively remove ammonium from water. This work further improved the sorption ability of biochars to aqueous ammonium through alkali modification. Three modified biochars were prepared from agricultural residuals pre-treated with NaOH solution through low-temperature (300 °C slow pyrolysis. The modified biochars effectively removed ammonium ions from water under various conditions with relatively fast adsorption kinetics (reached equilibrium within 10 h and extremely high adsorption capacity (>200 mg/g. The Langmuir maximum capacity of the three modified biochars were between 313.9 and 518.9 mg/g, higher than many other ammonium adsorbents. Although the sorption of ammonium onto the modified biochar was affected by pH and temperature, it was high under all of the tested conditions. Findings from this work indicated that alkali-modified biochars can be used as an alternative adsorbent for the removal of ammonium from wastewater.

  12. Erratum to ;Coastal water column ammonium and nitrite oxidation are decoupled in summer;

    Science.gov (United States)

    Heiss, Elise M.; Fulweiler, Robinson W.

    2017-07-01

    Water column nitrification is a key process in the nitrogen cycle as it links reduced and oxidized forms of nitrogen and also provides the substrate (nitrate) needed for reactive nitrogen removal by denitrification. We measured potential water column ammonium and nitrite oxidation rates at four sites along an estuary to continental shelf gradient over two summers. In most cases, nitrite oxidation rates outpaced ammonium oxidation rates. Overall, ammonium and nitrite oxidation rates were higher outside of the estuary, and this trend was primarily driven by higher oxidation rates in deeper waters. Additionally, both ammonium and nitrite oxidation rates were impacted by different in situ variables. Ammonium oxidation rates throughout the water column as a whole were most positively correlated to depth and salinity and negatively correlated to dissolved oxygen, light, and temperature. In contrast, nitrite oxidation rates throughout the water column were negatively correlated with temperature, light and pH. Multivariate regression analysis revealed that surface (20 m) rates were regulated by temperature, light, and [H+] (i.e. pH). In addition, surface (20 m) nitrite oxidation rates. These results support the growing body of evidence that ammonium oxidation and nitrite oxidation are not always coupled, should be measured separately, and are influenced by different environmental conditions.

  13. stripping of uranium from DEHPA/TOPO solvent by ammonium carbonate solutions

    International Nuclear Information System (INIS)

    Khorfan, S.; Shino, O.; Wahood, A.; Dahdouh, A.

    2002-01-01

    Uranium is recovered from phosphoric acid by the DEHPA/TOPO process. In this process uranium is stripped from the loaded DEHPA/TOPO solvent in the second cycle by an ammonium carbonate solution. This paper studied stripping of uranium from 0.3 Mol DEHPA/0.075 Mol TOPO in kerosene by different ammonium carbonate solutions. The ammonium carbonate solutions tested were either made locally from ammonia and carbon dioxide gases or commercial and laboratory grades available on the market. A comparison was made between these carbonate solutions in terms of purity, stripping efficiency and phase separation. Both stripping and phase separation were carried out under different conditions of phase ratio and concentrations. The results obtained showed that ammonium carbonate prepared from direct synthesis of ammonia and carbon dioxide gases had a high purity and gave the same stripping yield as the laboratory grade. The phase separation was also slightly improved using a pure synthesized ammonium carbonate solution. the phase separation was found to be best at concentration of 0.5 Mol/L ammonium carbonate solution and at a phase A/O of 1/1 and a temperature of 50 degree centigrade. It was possible to obtain >99% yield by operating 2 stripping stages counter currently under these conditions. (authors)

  14. Depositional ice nucleation on solid ammonium sulfate and glutaric acid particles

    Directory of Open Access Journals (Sweden)

    K. J. Baustian

    2010-03-01

    Full Text Available Heterogeneous ice nucleation on solid ammonium sulfate and glutaric acid particles was studied using optical microscopy and Raman spectroscopy. Optical microscopy was used to detect selective nucleation events as water vapor was slowly introduced into an environmental sample cell. Particles that nucleated ice were dried via sublimation and examined in detail using Raman spectroscopy. Depositional ice nucleation is highly selective and occurred preferentially on just a few ammonium sulfate and glutaric acid particles in each sample. For freezing temperatures between 214 K and 235 K an average ice saturation ratio of S = 1.10±0.07 for solid ammonium sulfate was observed. Over the same temperature range, S values observed for ice nucleation on glutaric acid particles increased from 1.2 at 235 K to 1.6 at 218 K. Experiments with externally mixed particles further show that ammonium sulfate is a more potent ice nucleus than glutaric acid. Our results suggest that heterogeneous nucleation on ammonium sulfate may be an important pathway for atmospheric ice nucleation and cirrus cloud formation when solid ammonium sulfate aerosol particles are available for ice formation. This pathway for ice formation may be particularly significant near the tropical tropopause region where sulfates are abundant and other species known to be good ice nuclei are depleted.

  15. Application of Neesler reagent in the ammonium quantification used in the fermentations of biotechnology products

    Directory of Open Access Journals (Sweden)

    Dinorah Torres-Idavoy

    2015-08-01

    Full Text Available The ammonium salts are used in fermentations to supplement the deficient amounts of nitrogen and stabilize the pH of the culture medium. The excess ammonium ion exerts a detrimental effect on the fermentation process inhibiting microbial growth. An analytical method based on Neesler reagent was developed for monitoring and controlling the concentration of ammonium during the fermentation process. The test was standardized, by means of the selection of measuring equipment, and the reaction time as well as comparing standards of ammonium salts. The method was characterized with the evaluation of the next parameters: Specificity, Linearity and Range, Quantification Limit, Accuracy and Precision. The method proved to be specific. Two linear curves were defined in the ranges of concentrations of ammonium chloride salt (2-20 μg/ml and ammonium sulfate salt (5-30 μg/ml. The limits of quantification were the lowest points of each one. The method proved to be accurate and precise. This assay was applied to samples of the yeast culture and bacteria of the genus Saccharomyces and E. coli respectively. A novel method in micro plate for quantification and analytical control of ammonia was developed. This method is used to control this fundamental chemical component in the fermentations, to optimize the culture medium. Thus, an appropriate expression of recombinant proteins and proper vaccine candidates for clinical use are achieved

  16. Global zones of particle precipitation

    International Nuclear Information System (INIS)

    Miah, M.A.

    1988-01-01

    Magnetospheric particles are precipitated at low altitude all over the globe. The study of the physics of the equatorial global zone is important for geospace environment modeling, for knowing the loss processes of radiation belt particles and for the Space Station Project. The equatorial global zone was investigated by the Phoenix-1 experiment on board the S81-1 mission in May through November, 1982. The global profile of the peak flux of quasi-trapped protons follows the line of minimum magnetic field strength, with a FWHM of ∼13 degree in latitude. The pitch angle distribution anisotropy index is found to be 19± 2, and the protons show no statistically significant longitude dependence. Contrary to an earlier observation the author finds a strong altitude dependence. Within the altitude range of observation (∼160-285 km) the proton flux varies as the fifth power of altitude. This altitude gradient indicates a strong depletion of source neutrals, coupled with charge exchange loss and ionization loss of protons. A power law fit to the flux values of the previous observations, yields an energy spectral index of -2.55 ± 0.11, implying that the mean energy of the protons observed by Phoenix-1 is 1.3 MeV. For comparison of the observed proton population with the earlier observation, the response functions of both instruments - the monitor telescope on the S81-1 mission, and the EI-92 telescope on the Azur mission-have been calculated as a function of the satellite orbital parameters and instrument geometry, both in the dipole and real magnetic field models

  17. Droplet nuclei in non-precipitating clouds: composition and size matter

    International Nuclear Information System (INIS)

    Twohy, Cynthia H; Anderson, James R

    2008-01-01

    The composition of cloud droplet nuclei was compared to the composition of ambient aerosol particles in non-precipitating clouds in different regions. Single-particle electron microscope techniques were used to identify particle types. The smallest particles (<0.2 μm diameter) exhibited a dependence of composition on nucleating ability, with salts (chlorides and sulfates of Na, K, Ca and Mg) being preferred nuclei types, followed by ammonium sulfates and organics. Crustal and industrial metals were less likely to be incorporated into cloud droplets. However, for experiments where only larger particles were sampled, a weaker dependence on composition was found. This suggests that larger particles have sufficient soluble material to nucleate despite their primary type. Both size and composition seem to be important, with composition becoming increasingly important as smaller particles activate at higher supersaturations in the cloudy environment.

  18. A comparative approach to synthesis and sintering of alumina/yttria nanocomposite powders using different precipitants

    Energy Technology Data Exchange (ETDEWEB)

    Kafili, G. [Department of Nanotechnology Engineering, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan, 81746-73441 (Iran, Islamic Republic of); Movahedi, B., E-mail: b.movahedi@ast.ui.ac.ir [Department of Nanotechnology Engineering, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan, 81746-73441 (Iran, Islamic Republic of); Milani, M. [Faculty of Advanced Materials and Renewable Energy Research Center, Tehran (Iran, Islamic Republic of)

    2016-11-01

    Alumina/yttria nanocomposite powder as an yttrium aluminum garnet (YAG) precursor was synthesized via partial wet route using urea and ammonium hydrogen carbonate (AHC) as precipitants, respectively. The products were characterized using X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and energy dispersive spectroscopy. The use of urea produced very tiny spherical Y-compounds with chemical composition of Y{sub 2}(CO{sub 3}){sub 3}·nH{sub 2}O, which were attracted to the surface of alumina nanoparticles and consequently, a core-shell structure was obtained. The use of ammonium hydrogen carbonate produced sheets of Y-compounds with chemical composition of Y(OH)CO{sub 3} covering the alumina nanoparticles. A fine-grained YAG ceramic (about 500 nm), presenting a non-negligible transparency (45% RIT at IR range) was obtained by the spark plasma sintering (SPS) of alumina-yttria nanocomposite synthesized in the urea system. This amount of transmission was obtained by only the sintering of the powder specimen without any colloidal forming process before sintering or adding any sintering aids or dopant elements. However, by spark plasma sintering of alumina-yttria nanocomposite powder synthesized in AHC system, an opaque YAG ceramic with an average grain size of 1.2 μm was obtained. - Highlights: • Urea proved to be an appropriate precipitant for obtaining a core-shell alumina/yttria nanocomposite. • Alumina/yttria nanocomposite powders with more appropriate morphology and highly sinterability. • A fine-grained YAG ceramic was obtained by SPS of alumina-yttria nanocomposite.

  19. The Global Precipitation Measurement (GPM) Project

    Science.gov (United States)

    Azarbarzin, Ardeshir; Carlisle, Candace

    2010-01-01

    The Global Precipitation Measurement (GP!v1) mission is an international cooperative effort to advance the understanding of the physics of the Earth's water and energy cycle. Accurate and timely knowledge of global precipitation is essential for understanding the weather/climate/ecological system, for improving our ability to manage freshwater resources, and for predicting high-impact natural hazard events including floods, droughts, extreme weather events, and landslides. The GPM Core Observatory will be a reference standard to uniformly calibrate data from a constellation of spacecraft with passive microwave sensors. GPM is being developed under a partnership between the United States (US) National Aeronautics and Space Administration (NASA) and the Japanese Aerospace and Exploration Agency (JAXA). NASA's Goddard Space Flight Center (GSFC), in Greenbelt, MD is developing the Core Observatory, two GPM Microwave Imager (GMI) instruments, Ground Validation System and Precipitation Processing System for the GPM mission. JAXA will provide a Dual-frequency Precipitation Radar (DPR) for installation on the Core satellite and launch services for the Core Observatory. The second GMI instrument will be flown on a partner-provided spacecraft. Other US agencies and international partners contribute to the GPM mission by providing precipitation measurements obtained from their own spacecraft and/or providing ground-based precipitation measurements to support ground validation activities. The Precipitation Processing System will provide standard data products for the mission.

  20. Nitrogen Cycling in Seagrass Beds Dominated by Thalassia testudinum and Halodule wrightii: the Role of Nitrogen Fixation and Ammonium Oxidation in Regulating Ammonium Availability

    Science.gov (United States)

    Capps, R.; Caffrey, J. M.; Hester, C.

    2016-02-01

    Seagrass meadows provide key ecosystem services including nursery and foraging grounds, storm and erosion buffers, biodiversity enhancers and global carbon and nutrient cycling. Nitrogen concentrations are often very low in coastal waters and sediments, which may limit primary productivity. Biological nitrogen fixation is a microbial process that converts dinitrogen to ammonium, which is readily taken up by seagrasses. In the oxygenated rhizospheres, diazotrophs provide the plant with ammonium and use root exudates as an energy source. Nitrogen fixation rates and nutrient concentrations differ between seagrass species and substrate types. Thalassia testudinum has a higher biomass and is a climax species than Halodule wrightii, which is a pioneer species. Nitrogen fixation rates are relatively consistent in Thalassia testudinum dominated sediments. However, it is relatively variable in sediments occupied by Halodule wrightii. Nitrogen fixation rates are higher in bare substrate compared to areas with Thalassia testudinum, which may be due to T. testudinum's greater efficiency in nutrient retention because it is a climax species. We hypothesize that seasonal shifts in nitrogen fixation will coincide with seasonal shifts in seagrass biomass due to higher nutrient requirements during peak growth and lower requirements during senescence and dormancy. The ratio of porewater ammonium to phosphate suggests that seagrass growth may be nitrogen limited as does nitrogen demand, estimated from gross primary productivity. Significant rates of ammonium oxidation in both surface and rhizosphere sediments contribute to this imbalance. Thus, nitrogen fixation may be critical in supporting plant growth.

  1. Studies on the behavior of ammonia and ammonium salts in the atmosphere (1) - Fractional collection of ammonia gas and particulate ammonium

    Science.gov (United States)

    Kiin, K.; Fujimura, M.; Hashimoto, Y.

    1981-01-01

    Methods for the fractional collection of trace amounts of atmospheric ammonia gas and ammonium particles on a two staged glass fiber filter are summarized. A standard glass fiber filter washed with distilled water and dried at 120 to 130 C was used. A second filter was impregnated with a mixture of 3% boric acid and 25% glycerin solution. The blank of glass fiber filters impregnated with a mixture of the above solution was very low for ammonia, i.e. 0.06 micrograms in a filter of 47 mm in diameter. The mean concentrations of ammonia and ammonium in air at Kawasaki, a polluted area, were 7.6 and 2.3 micrograms cu m, and those at Sanriku, an unpolluted area 0.9 and 0.2 micrograms cu m, respectively. Ratios of concentration levels of ammonium to total ammonia in the atmosphere were 0.3 and 0.2 for the polluted and unpolluted areas, respectively. Ammonium salts in air at both areas were not correlated with relative humidity. Variations in time of ammonia concentrations and sources in surrounding areas are also considered.

  2. Higher Ammonium Transamination Capacity Can Alleviate Glutamate Inhibition on Winter Wheat (Triticum aestivum L.) Root Growth under High Ammonium Stress.

    Science.gov (United States)

    Wang, Feng; Gao, Jingwen; Liu, Yang; Tian, Zhongwei; Muhammad, Abid; Zhang, Yixuan; Jiang, Dong; Cao, Weixing; Dai, Tingbo

    2016-01-01

    Most of the studies about NH4+ stress mechanism simply address the effects of free NH4+, failing to recognize the changed nitrogen assimilation products. The objective of this study was to elucidate the effects of glutamate on root growth under high ammonium (NH4+) conditions in winter wheat (Triticum aestivum L.). Hydroponic experiments were conducted using two wheat cultivars, AK58 (NH4+-sensitive) and Xumai25 (NH4+-tolerant) with either 5 mM NH4+ nitrogen (AN) as stress treatment or 5 mM nitrate (NO3-) nitrogen as control. To evaluate the effects of NH4+-assimilation products on plant growth, 1 μM L-methionine sulfoximine (MSO) (an inhibitor of glutamine synthetase (GS)) and 1 mM glutamates (a primary N assimilation product) were added to the solutions, respectively. The AN significantly reduced plant biomass, total root length, surface area and root volume in both cultivars, but less effect was observed in Xumai25. The inhibition effects were alleviated by the application of MSO but strengthened by the application of glutamate. The AN increased the activities of GS, glutamate dehydrogenase (GDH) in both cultivars, resulting in higher glutamate contents. However, its contents were decreased by the application of MSO. Compared to AK58, Xumai25 showed lower glutamate contents due to its higher activities of glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT). With the indole-3-acetic acid (IAA) contents decreasing in roots, the ratio of shoot to root in IAA was increased, and further increased by the application of glutamate, and reduced by the application of MSO, but the ratio was lower in Xumai25. Meanwhile, the total soluble sugar contents and its root to shoot ratio also showed similar trends. These results indicate that the NH4+-tolerant cultivar has a greater transamination ability to prevent glutamate over-accumulation to maintain higher IAA transport ability, and consequently promoted soluble sugar transport to roots, further

  3. A substorm in midnight auroral precipitation

    Directory of Open Access Journals (Sweden)

    V. G. Vorobjev

    2003-12-01

    Full Text Available DMSP F7 spacecraft observations for the whole of 1986 were used to construct the empirical model of the midnight auroral precipitation during a substorm. The model includes the dynamics of different auroral precipitation boundaries and simultaneous changes in average electron precipitation energy and energy flux in different precipitation regions during all substorm phases, as well as the IMF and solar wind plasma signatures during a substorm. The analysis of the model shows a few important features of precipitation. (1 During the magnetic quietness and just before the beginning of the substorm expansive phase the latitudinal width of the auroral precipitation in the nightside sector is about 5 – 6° CGL, while that of the auroral oval is about 2 – 3° CGL during such periods. (2 For about 5 min before the substorm onset a decrease in the average precipitating electron energy in the equatorward part of auroral zone was observed simultaneously, with an increase in both the average electron energy and energy flux of electron precipitation in the poleward part of the auroral zone. (3 The isotropy boundary position in the beginning of the substorm expansive phase coincides well with the inner edge of the central plasma sheet. The analysis of interplanetary medium parameters shows that, on average, during the substorm development, the solar wind dynamic pressure was about 1.5 times that of the magnetic quietness period. Substorms occurred predominantly during the southward IMF orientation, suggesting that substorm onset often was not associated with the northern turn or decrease in the southward interplanetary Bz . The Northern Hemisphere’s substorms occurred generally during the positive interplanetary By in winter, and they were observed when the interplanetary By was negative in summer.Key words. Ionosphere (auroral ionosphere; particle precipitation – Magnetospheric physics (storm and substorm; magnetosphere-ionosphere interaction

  4. Fate of nitrate and origin of ammonium during infiltration of treated wastewater investigated through stable isotopes

    Science.gov (United States)

    Silver, Matthew; Schlögl, Johanna; Knöller, Kay; Schüth, Christoph

    2017-04-01

    The EU FP7 project MARSOL addresses water scarcity challenges in arid regions, where managed aquifer recharge (MAR) is an upcoming technology to recharge depleted aquifers using alternative water sources. However, a potential impact to water quality is increasing ammonium concentrations, which are known to be a problem resulting from bank filtration. In the context of MAR, increasing ammonium concentrations have received little attention so far. A soil column experiment was conducted to investigate transformations of nitrogen species when secondary treated wastewater (TWW) is infiltrated through a natural soil (organic matter content 5.6%) being considered for MAR. The TWW contains nitrate and dissolved organic nitrogen (DON), but typically very low (samples were collected from six depths. Results show that the largest decreases in nitrate concentration occur in the upper part of the soil, with on average 77% attenuated by 15 cm depth and 94% by 30 cm depth. Starting at 30 cm and continuing downward, ammonium concentrations increased, with concentrations reaching as high as 4 mg-N/L (the EU drinking water limit is 0.41 mg-N/L). Selected samples were also measured for stable nitrogen and oxygen isotopes. Nitrate became isotopically heavier (both N and O) with increasing depth (samples collected at 5 and 15 cm below the soil surface), with most results forming a linear trend for δ18O vs. δ15N. This pattern is consistent with denitrification, which is also supported by the fact that the ammonium concentration first increases at a depth below where most of the nitrate is consumed. However, the relationship between δ15N-NO3- and nitrate concentration is not clearly logarithmic, so processes other than denitrification are not ruled out for explaining the fate of nitrate. The δ15N of ammonium in the water samples and of nitrogen in the soil were also measured. With increasing depth and time, the δ15N-NH4+ (mean 4.3‰) decreases and approaches the δ15N of the pre

  5. Inorganic chemical precipitate formation payload design

    Science.gov (United States)

    Friedrich, Craig

    1988-01-01

    The Get Away Special payload to investigate the formation of inorganic precipitates (G-405) utilizes six transparent chemical reaction chambers to actively mix a dry powder with a liquid solution. At predetermined intervals the progress of the precipitate formation is photographed and stored as data. The precipitate particles will also be subject to post-flight analysis. The various tasks performed during the 14 hour duration of the experiment are initiated and monitored by a custom-built digital controller. The payload is currently scheduled as a backup payload for STS-29 with a possible launch date of January, 1989.

  6. Uranium peroxide precipitate drying temperature relationships

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, C.; Dyck, B., E-mail: chick_rodgers@cameco.com [Cameco Corp., Saskatoon, SK (Canada)

    2010-07-01

    Cameco Corporation is in the process of revitalizing the mill at its Key Lake operation in northern Saskatchewan. The current Key Lake process employs ammonia stripping and ammonia precipitation. As part of the revitalization, the company is considering installing strong acid stripping in solvent extraction as used at its Rabbit Lake operation. This change would lead to using hydrogen peroxide for uranium precipitation. As part of the process evaluation, tests were carried out to study how changes in the temperature of an indirect fired dryer affected the properties of uranium peroxide [yellowcake] precipitate. This paper discusses the results of the test work, including the relationships between drying temperature and the following: (author)

  7. Growth at low ammonium concentrations and starvation response as potential factors involved in niche differentiation among ammonia-oxidizing bacteria.

    Science.gov (United States)

    Bollmann, Annette; Bär-Gilissen, Marie-José; Laanbroek, Hendrikus J

    2002-10-01

    In nature, ammonia-oxidizing bacteria have to compete with heterotrophic bacteria and plants for limiting amounts of ammonium. Previous laboratory experiments conducted with Nitrosomonas europaea suggested that ammonia-oxidizing bacteria are weak competitors for ammonium. To obtain a better insight into possible methods of niche differentiation among ammonia-oxidizing bacteria, we carried out a growth experiment at low ammonium concentrations with N. europaea and the ammonia oxidizer G5-7, a close relative of Nitrosomonas oligotropha belonging to Nitrosomonas cluster 6a, enriched from a freshwater sediment. Additionally, we compared the starvation behavior of the newly enriched ammonia oxidizer G5-7 to that of N. europaea. The growth experiment at low ammonium concentrations showed that strain G5-7 was able to outcompete N. europaea at growth-limiting substrate concentrations of about 10 micro M ammonium, suggesting better growth abilities of the ammonia oxidizer G5-7 at low ammonium concentrations. However, N. europaea displayed a more favorable starvation response. After 1 to 10 weeks of ammonium deprivation, N. europaea became almost immediately active after the addition of fresh ammonium and converted the added ammonium within 48 to 96 h. In contrast, the regeneration time of the ammonia oxidizer G5-7 increased with increasing starvation time. Taken together, these results provide insight into possible mechanisms of niche differentiation for the ammonia-oxidizing bacteria studied. The Nitrosomonas cluster 6a member, G5-7, is able to grow at ammonium concentrations at which the growth of N. europaea, belonging to Nitrosomonas cluster 7, has already ceased, providing an advantage in habitats with continuously low ammonium concentrations. On the other hand, the ability of N. europaea to become active again after longer periods of starvation for ammonium may allow better exploitation of irregular pulses of ammonium in the environment.

  8. Differences in the reactivity of ammonium salts with methylamine

    Directory of Open Access Journals (Sweden)

    Y. Liu

    2012-06-01

    Full Text Available The heterogeneous uptake of methylamine (MA onto (NH42SO4, NH4HSO4, NH4NO3 and NH4Cl was investigated using a Knudsen cell reactor coupled to a quadrupole mass spectrometer, in situ Raman spectrometer and theoretical calculations. Exchange reactions were observed between MA and NH4NO3, (NH42SO4, and NH4Cl were observed at 298 K. Simple acid-base reaction for MA was found taking place on NH4HSO4. CH3NH3NO3 and CH3NH3Cl are not stable at low pressure and have higher dissociation vapor pressure than methylammonium sulfate. The observed uptake coefficients of MA on (NH42SO4, NH4HSO4, NH4NO3 and NH4Cl at 298 K were measured to be 6.30±1.03×10−3, 1.78±0.36×10−2, 8.79±1.99×10−3 and 2.29±0.28×10−3, respectively. A linear free energy relationship was found for the heterogeneous reactions between MA and NH4Cl, (NH42SO4 and NH4NO3. Namely, the natural logarithm of uptake coefficients of MA on these ammonium salts is linearly related to the electrostatic potential of the H atom in the NH4+ group.

  9. Stable isotope analyses of precipitation nitrogen sources in Guiyang, southwestern China.

    Science.gov (United States)

    Liu, Xue-Yan; Xiao, Hong-Wei; Xiao, Hua-Yun; Song, Wei; Sun, Xin-Chao; Zheng, Xu-Dong; Liu, Cong-Qiang; Koba, Keisuke

    2017-11-01

    To constrain sources of anthropogenic nitrogen (N) deposition is critical for effective reduction of reactive N emissions and better evaluation of N deposition effects. This study measured δ 15 N signatures of nitrate (NO 3 - ), ammonium (NH 4 + ) and total dissolved N (TDN) in precipitation at Guiyang, southwestern China and estimated contributions of dominant N sources using a Bayesian isotope mixing model. For NO 3 - , the contribution of non-fossil N oxides (NO x , mainly from biomass burning (24 ± 12%) and microbial N cycle (26 ± 5%)) equals that of fossil NO x , to which vehicle exhausts (31 ± 19%) contributed more than coal combustion (19 ± 9%). For NH 4 + , ammonia (NH 3 ) from volatilization sources (mainly animal wastes (22 ± 12%) and fertilizers (22 ± 10%)) contributed less than NH 3 from combustion sources (mainly biomass burning (17 ± 8%), vehicle exhausts (19 ± 11%) and coal combustions (19 ± 12%)). Dissolved organic N (DON) accounted for 41% in precipitation TDN deposition during the study period. Precipitation DON had higher δ 15 N values in cooler months (13.1‰) than in warmer months (-7.0‰), indicating the dominance of primary and secondary ON sources, respectively. These results newly underscored the importance of non-fossil NO x , fossil NH 3 and organic N in precipitation N inputs of urban environments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Urea Hydrolysis and Calcium Carbonate Precipitation in Gypsum-Amended Broiler Litter.

    Science.gov (United States)

    Burt, Christopher D; Cabrera, Miguel L; Rothrock, Michael J; Kissel, D E

    2018-01-01

    Broiler () litter is subject to ammonia (NH) volatilization losses. Previous work has shown that the addition of gypsum to broiler litter can increase nitrogen mineralization and decrease NH losses due to a decrease in pH, but the mechanisms responsible for these effects are not well understood. Therefore, three laboratory studies were conducted to evaluate the effect of gypsum addition to broiler litter on (i) urease activity at three water contents, (ii) calcium carbonate precipitation, and (iii) pH. The addition of gypsum to broiler litter increased ammonium concentrations ( litter pH by 0.43 to 0.49 pH units after 5 d ( litter only increased on Day 0 for broiler litter with low (0.29 g HO g) and high (0.69 g HO g) water contents, and on Day 3 for litter with medium (0.40 g HO g) water content ( litter with gypsum also caused an immediate decrease in litter pH (0.22 pH units) due to the precipitation of calcium carbonate (CaCO) from gypsum-derived calcium and litter bicarbonate. Furthermore, as urea was hydrolyzed, more urea-derived carbon precipitated as CaCO in gypsum-treated litter than in untreated litter ( litter with gypsum favors the precipitation of CaCO, which buffers against increases in litter pH that are known to facilitate NH volatilization. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  11. The evolution of hydrogen and iodine by the decomposition of ammonium iodide and hydrogen iodide

    International Nuclear Information System (INIS)

    Ishikawa, Hiroshi; Nakane, Masanori; Ishii, Eiichi; Uehara, Itsuki; Miyake, Yoshizo

    1977-01-01

    As a fundamental study on thermochemical production of hydrogen from water, the evolution of hydrogen and iodine from ammonium iodide and hydrogen iodide was investigated. Hydrogen was evolved by the reaction of nickel with ammonium iodide or with hydrogen iodide, and the resulting nickel(II) iodide was decomposed thermally at 600 -- 700 0 C to form nickel. First, the iodination of powdered nickel with ammonium iodide was studied by heating their powder mixture. The maximum yield of hydrogen was obtained at a temperature near 430 0 C. The iodination of powdered nickel with gaseous ammonium iodide or with dry hydrogen iodide gas was also investigated. In this case, coating of nickel particles with a layer of resulting nickel(II) iodide prevented further conversion of nickel and lowered the reaction rate. Such a retardation effect was appreciably lessened by use of carrier. When nickel was supported on such a carrier as ''isolite'', the nickel was converted into nickel(II) iodide easily. In a reaction temperature from 400 to 500 0 C, the rate of reaction between nickel and hydrogen iodide increased slightly with the elevation of the reaction temperature. In the case of ammonium iodide, the reaction rate was higher than that for hydrogen iodide and decreased apparently with the elevation of the reaction temperature, because ammonium iodide decomposed to ammonia and hydrogen iodide. Tests using a fixed bed reactor charged with 8 -- 10 mesh ''isolite''-nickel (30 wt%) were also carried out. The maximum yield of hydrogen was about 80% for ammonium iodide at 430 0 C of reaction temperature and 60% for hydrogen iodide at 500 0 C. (auth.)

  12. Replacement of ammonium chloride when processing Scholven coals. (Tests conducted in rotating autoclave at 350 atmosheres. )

    Energy Technology Data Exchange (ETDEWEB)

    Grassl, G.; Schiffmann, F.

    1944-01-03

    Hydrogenation tests were conducted on coal from Scholven in view of difficulties in delivery of ammonium chloride to the Scholven works. The results were, that of the materials containing chlorine, ferrous chloride and water-soluble chlorine-bearing alumina appeared to be first and second choices as replacements for ammonium chloride. Ferrous chloride, used for an equivalent amount of chlorine, gave, other than a bit higher volatilization, the same results as ammonium chloride. Water-soluble chlorine-bearing alumina was found to be just as favorable as the ammonium chloride. But, there was a disadvantage. Since the alumina carried a lesser amount of chloride, a relatively larger amount (5.9%) of the material had to be used. This caused another problem. The increased residual material caused an overload on the reprocessing system. Water-soluble alumina at 1.9% was found to be unsuitable, because volatilization rose considerably with higher temperatures. Hydrated aluminum chloride (AlCl/sub 3/ . 6H/sub 2/O) was significantly more unsuitable than ammonium chloride. It was found that at .3 mV higher temperature, significant improvement could be noted, but certainly at the cost of volatilization, which rose sharply. Two tests of aluminum oxychloride, which contained more chlorine than the water-soluble alumina, showed suitable cracking properties, but figures as good as those obtained with ammonium chloride were not reached in treating asphalt and volatilization. Attempts to activate the chlorine in sodium chloride through ion exchange with ammonium sulfate did not succeed. The resulting substance gave worse results than did aluminum chlorohydrate. 1 table

  13. Thermal stability and kinetics of decomposition of ammonium nitrate in the presence of pyrite

    International Nuclear Information System (INIS)

    Gunawan, Richard; Zhang Dongke

    2009-01-01

    The interaction between ammonium nitrate based industrial explosives and pyrite-rich minerals in mining operations can lead to the occurrence of spontaneous explosion of the explosives. In an effort to provide a scientific basis for safe applications of industrial explosives in reactive mining grounds containing pyrite, ammonium nitrate decomposition, with and without the presence of pyrite, was studied using a simultaneous Differential Scanning Calorimetry and Thermogravimetric Analyser (DSC-TGA) and a gas-sealed isothermal reactor, respectively. The activation energy and the pre-exponential factor of ammonium nitrate decomposition were determined to be 102.6 kJ mol -1 and 4.55 x 10 7 s -1 without the presence of pyrite and 101.8 kJ mol -1 and 2.57 x 10 9 s -1 with the presence of pyrite. The kinetics of ammonium nitrate decomposition was then used to calculate the critical temperatures for ammonium nitrate decomposition with and without the presence of pyrite, based on the Frank-Kamenetskii model of thermal explosion. It was shown that the presence of pyrite reduces the temperature for, and accelerates the rate of, decomposition of ammonium nitrate. It was further shown that pyrite can significantly reduce the critical temperature of ammonium nitrate decomposition, causing undesired premature detonation of the explosives. The critical temperature also decreases with increasing diameter of the blast holes charged with the explosive. The concept of using the critical temperature as indication of the thermal stability of the explosives to evaluate the risk of spontaneous explosion was verified in the gas-sealed isothermal reactor experiments.

  14. U.S. Hourly Precipitation Data Publication

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This publication contains hourly precipitation amounts obtained from recording rain gages located at National Weather Service, Federal Aviation Administration, and...

  15. Identifying external influences on global precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Marvel, K.; Bonfils, C.

    2013-11-11

    Changes in global (ocean and land) precipitation are among the most important and least well-understood consequences of climate change. Increasing greenhouse gas concentrations are thought to affect the zonal-mean distribution of precipitation through two basic mechanisms. First, increasing temperatures will lead to an intensification of the hydrological cycle (“thermodynamic” changes). Second, changes in atmospheric circulation patterns will lead to poleward displacement of the storm tracks and subtropical dry zones and to a widening of the tropical belt (“dynamic” changes). We demonstrate that both these changes are occurring simultaneously in global precipitation, that this behavior cannot be explained by internal variability alone, and that external influences are responsible for the observed precipitation changes. Whereas existing model experiments are not of sufficient length to differentiate between natural and anthropogenic forcing terms at the 95% confidence level, we present evidence that the observed trends result from human activities.

  16. VT Mean Winter Precipitation - 1971-2000

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) ClimatePrecip_PRECIPW7100 includes mean winter precipitation data (October through March) for Vermont (1971-2000). It's a raster dataset derived...

  17. NESDIS Blended Total Precipitable Water (TPW) Products

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The blended Total Precipitable Water (TPW) product is derived from multiple sensors/satellites. The Percentage of TPW normal (PCT), or TPW anomaly, shows the...

  18. Precipitation Reconstruction over Land (PREC/L)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The monthly data set consists files of 3 resolutions of monthly averaged precipitation totals. The global analyses are defined by interpolation of gauge observations...

  19. Three Band Cloud and Precipitation Radar

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to design and demonstrate key enabling technologies for Cloud and Precipitation radars capable of closing the observational gaps left by current and...

  20. U.S. Hourly Precipitation Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hourly Precipitation Data (HPD) is digital data set DSI-3240, archived at the National Climatic Data Center (NCDC). The primary source of data for this file is...

  1. Scaling behaviors of precipitation over China

    Science.gov (United States)

    Jiang, Lei; Li, Nana; Zhao, Xia

    2017-04-01

    Scaling behaviors in the precipitation time series derived from 1951 to 2009 over China are investigated by detrended fluctuation analysis (DFA) method. The results show that there exists long-term memory for the precipitation time series in some stations, where the values of the scaling exponent α are less than 0.62, implying weak persistence characteristics. The values of scaling exponent in other stations indicate random behaviors. In addition, the scaling exponent α in precipitation records varies from station to station over China. A numerical test is made to verify the significance in DFA exponents by shuffling the data records many times. We think it is significant when the values of scaling exponent before shuffled precipitation records are larger than the interval threshold for 95 % confidence level after shuffling precipitation records many times. By comparison, the daily precipitation records exhibit weak positively long-range correlation in a power law fashion mainly at the stations taking on zonal distributions in south China, upper and middle reaches of the Yellow River, northern part of northeast China. This may be related to the subtropical high. Furthermore, the values of scaling exponent which cannot pass the significance test do not show a clear distribution pattern. It seems that the stations are mainly distributed in coastal areas, southwest China, and southern part of north China. In fact, many complicated factors may affect the scaling behaviors of precipitation such as the system of the east and south Asian monsoon, the interaction between sea and land, and the big landform of the Tibetan Plateau. These results may provide a better prerequisite to long-term predictor of precipitation time series for different regions over China.

  2. Global Precipitation Measurement (GPM) L-6

    Science.gov (United States)

    Neeck, Steven P.; Kakar, Ramesh K.; Azarbarzin, Ardeshir A.; Hou, Arthur Y.

    2013-10-01

    The Global Precipitation Measurement (GPM) mission will advance the measurement of global precipitation, making possible high spatial resolution precipitation measurements. GPM will provide the first opportunity to calibrate measurements of global precipitation across tropical, mid-latitude, and polar regions. The GPM mission has the following scientific objectives: (1) Advance precipitation measurement capability from space through combined use of active and passive remote-sensing techniques; (2) Advance understanding of global water/energy cycle variability and fresh water availability; (3) Improve climate prediction by providing the foundation for better understanding of surface water fluxes, soil moisture storage, cloud/precipitation microphysics and latent heat release in the Earth's atmosphere; (4) Advance Numerical Weather Prediction (NWP) skills through more accurate and frequent measurements of instantaneous rain rates; and (5) Improve high impact natural hazard (flood/drought, landslide, and hurricane hazard) prediction capabilities. The GPM mission centers on the deployment of a Core Observatory carrying an advanced radar / radiometer system to measure precipitation from space and serve as a reference standard to unify precipitation measurements from a constellation of research and operational satellites. GPM, jointly led with the Japan Aerospace Exploration Agency (JAXA), involves a partnership with other international space agencies including the French Centre National d'Études Spatiales (CNES), the Indian Space Research Organisation (ISRO), the U.S. National Oceanic and Atmospheric Administration (NOAA), the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), and others. The GPM Core Observatory is currently being prepared for shipment to Japan for launch. Launch is scheduled for February 2014 from JAXA's Tanegashima Space Center on an H-IIA 202 launch vehicle.

  3. Precipitation Nowcast using Deep Recurrent Neural Network

    Science.gov (United States)

    Akbari Asanjan, A.; Yang, T.; Gao, X.; Hsu, K. L.; Sorooshian, S.

    2016-12-01

    An accurate precipitation nowcast (0-6 hours) with a fine temporal and spatial resolution has always been an important prerequisite for flood warning, streamflow prediction and risk management. Most of the popular approaches used for forecasting precipitation can be categorized into two groups. One type of precipitation forecast relies on numerical modeling of the physical dynamics of atmosphere and another is based on empirical and statistical regression models derived by local hydrologists or meteorologists. Given the recent advances in artificial intelligence, in this study a powerful Deep Recurrent Neural Network, termed as Long Short-Term Memory (LSTM) model, is creatively used to extract the patterns and forecast the spatial and temporal variability of Cloud Top Brightness Temperature (CTBT) observed from GOES satellite. Then, a 0-6 hours precipitation nowcast is produced using a Precipitation Estimation from Remote Sensing Information using Artificial Neural Network (PERSIANN) algorithm, in which the CTBT nowcast is used as the PERSIANN algorithm's raw inputs. Two case studies over the continental U.S. have been conducted that demonstrate the improvement of proposed approach as compared to a classical Feed Forward Neural Network and a couple simple regression models. The advantages and disadvantages of the proposed method are summarized with regard to its capability of pattern recognition through time, handling of vanishing gradient during model learning, and working with sparse data. The studies show that the LSTM model performs better than other methods, and it is able to learn the temporal evolution of the precipitation events through over 1000 time lags. The uniqueness of PERSIANN's algorithm enables an alternative precipitation nowcast approach as demonstrated in this study, in which the CTBT prediction is produced and used as the inputs for generating precipitation nowcast.

  4. Harmonic analysis of the precipitation in Greece

    Science.gov (United States)

    Nastos, P. T.; Zerefos, C. S.

    2009-04-01

    Greece is a country with a big variety of climates due to its geographical position, to the many mountain ranges and also to the multifarious and long coastline. The mountainous volumes are of such orientation that influences the distribution of the precipitation, having as a result, Western Greece to present great differentiations from Central and Eastern Greece. The application of harmonic analysis to the annual variability of precipitation is the goal of this study, so that the components, which compose the annual variability, be elicited. For this purpose, the mean monthly precipitation data from 30 meteorological stations of National Meteorological Service were used for the time period 1950-2000. The initial target is to reduce the number of variables and to detect structure in the relationships between variables. The most commonly used technique for this purpose is the application of Factor Analysis to a table having as columns the meteorological stations-variables and rows the monthly mean precipitation, so that 2 main factors were calculated, which explain the 98% of total variability of precipitation in Greece. Factor 1, representing the so-called uniform field and interpreting the most of the total variance, refers in fact to the Mediterranean depressions, affecting mainly the West of Greece and also the East Aegean and the Asia Minor coasts. In the process, the Fourier Analysis was applied to the factor scores extracted from the Factor Analysis, so that 2 harmonic components are resulted, which explain above the 98% of the total variability of each main factor, and are due to different synoptic and thermodynamic processes associated with Greece's precipitation construction. Finally, the calculation of the time of occurrence of the maximum precipitation, for each harmonic component of each one of the two main factors, gives the spatial distribution of appearance of the maximum precipitation in the Hellenic region.

  5. Kinetics of niobium carbide precipitation in ferrite

    International Nuclear Information System (INIS)

    Gendt, D.

    2001-01-01

    The aim of this study is to develop a NbC precipitation modelling in ferrite. This theoretical study is motivated by the fact it considers a ternary system and focus on the concurrence of two different diffusion mechanisms. An experimental study with TEP, SANS and Vickers micro-hardening measurements allows a description of the NbC precipitation kinetics. The mean radius of the precipitates is characterized by TEM observations. To focus on the nucleation stage, we use the Tomographic Atom Probe that analyses, at an atomistic scale, the position of the solute atoms in the matrix. A first model based on the classical nucleation theory and the diffusion-limited growth describes the precipitation of spherical precipitates. To solve the set of equations, we use a numerical algorithm that furnishes an evaluation of the precipitated fraction, the mean radius and the whole size distribution of the particles. The parameters that are the interface energy, the solubility product and the diffusion coefficients are fitted with the data available in the literature and our experimental results. It allows a satisfactory agreement as regards to the simplicity of the model. Monte Carlo simulations are used to describe the evolution of a ternary alloy Fe-Nb-C on a cubic centred rigid lattice with vacancy and interstitial mechanisms. This is realized with an atomistic description of the atoms jumps and their related frequencies. The model parameters are fitted with phase diagrams and diffusion coefficients. For the sake of simplicity, we consider that the precipitation of NbC is totally coherent and we neglect any elastic strain effect. We can observe different kinetic paths: for low supersaturations, we find an expected precipitation of NbC but for higher supersaturations, the very fast diffusivity of carbon atoms conducts to the nucleation of iron carbide particles. We establish that the occurrence of this second phenomenon depends on the vacancy arrival kinetics and can be related

  6. Climate Prediction Center (CPC) Global Precipitation Time Series

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The global precipitation time series provides time series charts showing observations of daily precipitation as well as accumulated precipitation compared to normal...

  7. Strong increase in convective precipitation in response to higher temperatures

    DEFF Research Database (Denmark)

    Berg, P.; Moseley, C.; Härter, Jan Olaf Mirko

    2013-01-01

    Precipitation changes can affect society more directly than variations in most other meteorological observables, but precipitation is difficult to characterize because of fluctuations on nearly all temporal and spatial scales. In addition, the intensity of extreme precipitation rises markedly at ...

  8. Comparison of different ecological remediation methods for removing nitrate and ammonium in Qinshui River, Gonghu Bay, Taihu Lake.

    Science.gov (United States)

    Wang, Hao; Li, Zhengkui; Han, Huayang

    2017-01-01

    Ecological remediation is one of the most practical methods for removing nutrients from river ecosystems. In this study, transformation and fate of nitrate and ammonium among four different ecological restoration treatments were investigated by stable 15 N isotope pairing technique combined with quantitative polymerase chain reaction and high-throughput sequencing technology. The results of 15 N mass-balance model showed that there were three ways to the fate of nitrogen: precipitated in the sediment, absorbed by Elodea nuttallii (E. nuttallii), and consumed by microbial processes (denitrification and anaerobic ammonium oxidation (anammox)). The results shown that the storage of 15 NH 4 + in sediments was about 1.5 times as much as that of 15 NO 3 - . And much more 15 NH 4 + was assimilated by E. nuttallii, about 2 times as much as 15 NO 3 - . Contrarily, the rate of microbial consuming 15 NO 3 - was higher than converting 15 NH 4 + . As for the group with 15 NO 3 - added, 29.61, 45.26, 30.66, and 51.95 % were accounted for 15 N-labeled gas emission. The proportions of 15 NH 4 + loss as 15 N-labeled gas were 16.06, 28.86, 16.93, and 33.09 % in four different treatments, respectively. Denitrification and anammox were the bacterial primary processes in N 2 and N 2 O production. The abundances of denitrifying and anammox functional genes were relatively higher in the treatment with E. nuttallii-immobilized nitrogen cycling bacteria (E-INCB) assemblage technology applied. Besides, microbial diversity increased in the treatment with E. nuttallii and INCB added. The 15 NO 3 - removal rates were 35.27, 49.42, 50.02, and 65.46 % in four different treatments. And the removal rates of 15 NH 4 + were 24, 34.38, 48.84, and 57.74 % in treatments A, B, C, and D, respectively. The results indicated that E-INCB assemblage technology could significantly promote the nitrogen cycling and improve nitrogen removal efficiency.

  9. How is climate change impacting precipitation?

    Science.gov (United States)

    Heidari, A.; Houser, P. R.

    2015-12-01

    Water is an integrating component of the climate, energy and geochemical cycles, regulating biological and ecological activities at all spatial and temporal scales. The most significant climate warming manifestation would be a change in the distribution of precipitation and evaporation, and the exacerbation of extreme hydrologic events. Due to this phenomenon and the fact that precipitation is the most important component of the water cycle, the assumption of its stationarity for water management and engineering design should be examined closely. The precipitation Annual Maximum Series (AMS) over some stations in Virginia based on in situ data were been used as a starting point to examine this important issue. We analyzed the AMS precipitation on NOAA data for the stations close to Fairfax VA, looked for trends in extreme values, and applied our new method of Generalized Extreme Value (GEV) theory based on quadratic forms to address changes in those extreme values and to quantify non-stationarities. It is very important to address the extreme values of precipitation based on several statistical tests to have better understanding of climate change impact on the extreme water cycle events. In our study we compared our results with the conclusion on NOAA atlas 14 Ap.3 which found no sign of precipitation non-stationarity. We then assessed the impact of this uncertainty in IDF curves on the flood map of Fairfax and compared the results with the classic IDF curves.

  10. Precipitation response to regional radiative forcing

    Directory of Open Access Journals (Sweden)

    D. T. Shindell

    2012-08-01

    Full Text Available Precipitation shifts can have large impacts on human society and ecosystems. Many aspects of how inhomogeneous radiative forcings influence precipitation remain unclear, however. Here we investigate regional precipitation responses to various forcings imposed in different latitude bands in a climate model. We find that several regions show strong, significant responses to most forcings, but that the magnitude and even the sign depends upon the forcing location and type. Aerosol and ozone forcings typically induce larger responses than equivalent carbon dioxide (CO2 forcing, and the influence of remote forcings often outweighs that of local forcings. Consistent with this, ozone and especially aerosols contribute greatly to precipitation changes over the Sahel and South and East Asia in historical simulations, and inclusion of aerosols greatly increases the agreement with observed trends in these areas, which cannot be attributed to either greenhouse gases or natural forcings. Estimates of precipitation responses derived from multiplying our Regional Precipitation Potentials (RPP; the response per unit forcing relationships by historical forcings typically capture the actual response in full transient climate simulations fairly well, suggesting that these relationships may provide useful metrics. The strong sensitivity to aerosol and ozone forcing suggests that although some air quality improvements may unmask greenhouse gas-induced warming, they have large benefits for reducing regional disruption of the hydrologic cycle.

  11. Precipitation in a lead calcium tin anode

    International Nuclear Information System (INIS)

    Pérez-González, Francisco A.; Camurri, Carlos G.; Carrasco, Claudia A.; Colás, Rafael

    2012-01-01

    Samples from a hot rolled sheet of a tin and calcium bearing lead alloy were solution heat treated at 300 °C and cooled down to room temperature at different rates; these samples were left at room temperature to study natural precipitation of CaSn 3 particles. The samples were aged for 45 days before analysing their microstructure, which was carried out in a scanning electron microscope using secondary and backscattered electron detectors. Selected X-ray spectra analyses were conducted to verify the nature of the precipitates. Images were taken at different magnifications in both modes of observation to locate the precipitates and record their position within the images and calculate the distance between them. Differential scanning calorimeter analyses were conducted on selected samples. It was found that the mechanical properties of the material correlate with the minimum average distance between precipitates, which is related to the average cooling rate from solution heat treatment. - Highlights: ► The distance between precipitates in a lead alloy is recorded. ► The relationship between the distance and the cooling rate is established. ► It is found that the strengthening of the alloy depends on the distance between precipitates.

  12. Mechanisms affecting swelling in alloys with precipitates

    International Nuclear Information System (INIS)

    Mansur, L.K.; Haynes, M.R.; Lee, E.H.

    1980-01-01

    In alloys under irradiation many mechanisms exist that couple phase instability to cavity swelling. These are compounded with the more familiar mechanisms associated with point defect behavior and the evolution of microstructure. The mechanisms may be classified according to three modes of operation. Some affect cavity swelling directly by cavity-precipitate particle association, others operate indirectly by precipitate-induced changes in sinks other than cavities and finally there are mechanisms that are mediated by precipitate-induced changes in the host matrix. The physics of one mechanism of each type is developed in detail and the results compared where possible to experimental measurements. In particular, we develop the theory necessary to treat the effects on swelling of precipitation-induced changes in overall sink density; precipitation-induced changes in point defect trapping by solute depletion and creation of precipitate particle-matrix interfacial trap sites; and preciwill come from waste wood available locally requiring minimal energy for recovery and transportation to the site. The applicant is strongly considering the use of a solar preheating unit anium southward as well as to deeper dened al half-lives with experimental ones, over a range of 24 orders of magnitude was obtained. This is a strong argument that the alpha decay could be considered a fission process with very high mass asymmetry and charge density asymmetry

  13. Multi-scale Quantitative Precipitation Forecasting Using ...

    Science.gov (United States)

    Global sea surface temperature (SST) anomalies can affect terrestrial precipitation via ocean-atmosphere interaction known as climate teleconnection. Non-stationary and non-linear characteristics of the ocean-atmosphere system make the identification of the teleconnection signals difficult to be detected at a local scale as it could cause large uncertainties when using linear correlation analysis only. This paper explores the relationship between global SST and terrestrial precipitation with respect to long-term non-stationary teleconnection signals during 1981-2010 over three regions in North America and one in Central America. Empirical mode decomposition as well as wavelet analysis is utilized to extract the intrinsic trend and the dominant oscillation of the SST and precipitation time series in sequence. After finding possible associations between the dominant oscillation of seasonal precipitation and global SST through lagged correlation analysis, the statistically significant SST regions are extracted based on the correlation coefficient. With these characterized associations, individual contribution of these SST forcing regions linked to the related precipitation responses are further quantified through nonlinear modeling with the aid of extreme learning machine. Results indicate that the non-leading SST regions also contribute a salient portion to the terrestrial precipitation variability compared to some known leading SST regions. In some cases, these

  14. Absence of the glutamine-synthetase-linked methylammonium (ammonium)-transport system in the cyanobiont of Cycas-cyanobacterial symbiosis.

    Science.gov (United States)

    Rai, A N; Lindblad, P; Bergman, B

    1986-11-01

    Using the ammonium analogue (14)CH3NH 3 (+) , ammonium transport was studied in the cyanobiont cells freshly isolated from the root nodules of Cycas revoluta. An L-methionine-DL-sulphoximine (MSX)-insensitive ammonium-transport system, which was dependent on membrane potential (ΔΨ), was found in the cyanobiont. However, the cyanobiont was incapable of metabolizing exogenous (14)CH3NH 3 (+) or NH 4 (+) because of the absence of another ammonium-transport system responsible for the uptake of ammonium for assimilation via glutamine synthetase (EC 6.3.1.2). Such a modification seems to be the result of symbiosis because the free-living cultured isolate, Anabaena cycadeae, has been shown to possess both the ammonium-transport systems.

  15. Higher Ammonium Transamination Capacity Can Alleviate Glutamate Inhibition on Winter Wheat (Triticum aestivum L.) Root Growth under High Ammonium Stress

    Science.gov (United States)

    Liu, Yang; Tian, Zhongwei; Muhammad, Abid; Zhang, Yixuan; Jiang, Dong; Cao, Weixing; Dai, Tingbo

    2016-01-01

    Most of the studies about NH4+ stress mechanism simply address the effects of free NH4+, failing to recognize the changed nitrogen assimilation products. The objective of this study was to elucidate the effects of glutamate on root growth under high ammonium (NH4+) conditions in winter wheat (Triticum aestivum L.). Hydroponic experiments were conducted using two wheat cultivars, AK58 (NH4+-sensitive) and Xumai25 (NH4+-tolerant) with either 5 mM NH4+ nitrogen (AN) as stress treatment or 5 mM nitrate (NO3-) nitrogen as control. To evaluate the effects of NH4+-assimilation products on plant growth, 1 μM L-methionine sulfoximine (MSO) (an inhibitor of glutamine synthetase (GS)) and 1 mM glutamates (a primary N assimilation product) were added to the solutions, respectively. The AN significantly reduced plant biomass, total root length, surface area and root volume in both cultivars, but less effect was observed in Xumai25. The inhibition effects were alleviated by the application of MSO but strengthened by the application of glutamate. The AN increased the activities of GS, glutamate dehydrogenase (GDH) in both cultivars, resulting in higher glutamate contents. However, its contents were decreased by the application of MSO. Compared to AK58, Xumai25 showed lower glutamate contents due to its higher activities of glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT). With the indole-3-acetic acid (IAA) contents decreasing in roots, the ratio of shoot to root in IAA was increased, and further increased by the application of glutamate, and reduced by the application of MSO, but the ratio was lower in Xumai25. Meanwhile, the total soluble sugar contents and its root to shoot ratio also showed similar trends. These results indicate that the NH4+-tolerant cultivar has a greater transamination ability to prevent glutamate over-accumulation to maintain higher IAA transport ability, and consequently promoted soluble sugar transport to roots, further

  16. Higher Ammonium Transamination Capacity Can Alleviate Glutamate Inhibition on Winter Wheat (Triticum aestivum L. Root Growth under High Ammonium Stress.

    Directory of Open Access Journals (Sweden)

    Feng Wang

    Full Text Available Most of the studies about NH4+ stress mechanism simply address the effects of free NH4+, failing to recognize the changed nitrogen assimilation products. The objective of this study was to elucidate the effects of glutamate on root growth under high ammonium (NH4+ conditions in winter wheat (Triticum aestivum L.. Hydroponic experiments were conducted using two wheat cultivars, AK58 (NH4+-sensitive and Xumai25 (NH4+-tolerant with either 5 mM NH4+ nitrogen (AN as stress treatment or 5 mM nitrate (NO3- nitrogen as control. To evaluate the effects of NH4+-assimilation products on plant growth, 1 μM L-methionine sulfoximine (MSO (an inhibitor of glutamine synthetase (GS and 1 mM glutamates (a primary N assimilation product were added to the solutions, respectively. The AN significantly reduced plant biomass, total root length, surface area and root volume in both cultivars, but less effect was observed in Xumai25. The inhibition effects were alleviated by the application of MSO but strengthened by the application of glutamate. The AN increased the activities of GS, glutamate dehydrogenase (GDH in both cultivars, resulting in higher glutamate contents. However, its contents were decreased by the application of MSO. Compared to AK58, Xumai25 showed lower glutamate contents due to its higher activities of glutamic-oxaloacetic transaminase (GOT and glutamic-pyruvic transaminase (GPT. With the indole-3-acetic acid (IAA contents decreasing in roots, the ratio of shoot to root in IAA was increased, and further increased by the application of glutamate, and reduced by the application of MSO, but the ratio was lower in Xumai25. Meanwhile, the total soluble sugar contents and its root to shoot ratio also showed similar trends. These results indicate that the NH4+-tolerant cultivar has a greater transamination ability to prevent glutamate over-accumulation to maintain higher IAA transport ability, and consequently promoted soluble sugar transport to roots

  17. Precipitation from Space: Advancing Earth System Science

    Science.gov (United States)

    Kucera, Paul A.; Ebert, Elizabeth E.; Turk, F. Joseph; Levizzani, Vicenzo; Kirschbaum, Dalia; Tapiador, Francisco J.; Loew, Alexander; Borsche, M.

    2012-01-01

    Of the three primary sources of spatially contiguous precipitation observations (surface networks, ground-based radar, and satellite-based radar/radiometers), only the last is a viable source over ocean and much of the Earth's land. As recently as 15 years ago, users needing quantitative detail of precipitation on anything under a monthly time scale relied upon products derived from geostationary satellite thermal infrared (IR) indices. The Special Sensor Microwave Imager (SSMI) passive microwave (PMW) imagers originated in 1987 and continue today with the SSMI sounder (SSMIS) sensor. The fortunate longevity of the joint National Aeronautics and Space Administration (NASA) and Japan Aerospace Exploration Agency (JAXA) Tropical Rainfall Measuring Mission (TRMM) is providing the environmental science community a nearly unbroken data record (as of April 2012, over 14 years) of tropical and sub-tropical precipitation processes. TRMM was originally conceived in the mid-1980s as a climate mission with relatively modest goals, including monthly averaged precipitation. TRMM data were quickly exploited for model data assimilation and, beginning in 1999 with the availability of near real time data, for tropical cyclone warnings. To overcome the intermittently spaced revisit from these and other low Earth-orbiting satellites, many methods to merge PMW-based precipitation data and geostationary satellite observations have been developed, such as the TRMM Multisatellite Precipitation Product and the Climate Prediction Center (CPC) morphing method (CMORPH. The purpose of this article is not to provide a survey or assessment of these and other satellite-based precipitation datasets, which are well summarized in several recent articles. Rather, the intent is to demonstrate how the availability and continuity of satellite-based precipitation data records is transforming the ways that scientific and societal issues related to precipitation are addressed, in ways that would not be

  18. Ammonia-Oxidizing Archaea Are More Resistant Than Denitrifiers to Seasonal Precipitation Changes in an Acidic Subtropical Forest Soil

    Directory of Open Access Journals (Sweden)

    Jie Chen

    2017-07-01

    Full Text Available Seasonal precipitation changes are increasingly severe in subtropical areas. However, the responses of soil nitrogen (N cycle and its associated functional microorganisms to such precipitation changes remain unclear. In this study, two projected precipitation patterns were manipulated: intensifying the dry-season drought (DD and extending the dry-season duration (ED but increasing the wet-season storms following the DD and ED treatment period. The effects of these two contrasting precipitation patterns on soil net N transformation rates and functional gene abundances were quantitatively assessed through a resistance index. Results showed that the resistance index of functional microbial abundance (-0.03 ± 0.08 was much lower than that of the net N transformation rate (0.55 ± 0.02 throughout the experiment, indicating that microbial abundance was more responsive to precipitation changes compared with the N transformation rate. Spring drought under the ED treatment significantly increased the abundances of both nitrifying (amoA and denitrifying genes (nirK, nirS, and nosZ, while changes in these gene abundances overlapped largely with control treatment during droughts in the dry season. Interestingly, the resistance index of the ammonia-oxidizing archaea (AOA amoA abundance was significantly higher than that of the denitrifying gene abundances, suggesting that AOA were more resistant to the precipitation changes. This was attributed to the stronger environmental adaptability and higher resource utilization efficiency of the AOA community, as indicated by the lack of correlations between AOA gene abundance and environmental factors [i.e., soil water content, ammonium (NH4+ and dissolved organic carbon concentrations] during the experiment.

  19. A Novel Analytical Method for Trace Ammonium in Freshwater and Seawater Using 4-Methoxyphthalaldehyde as Fluorescent Reagent

    OpenAIRE

    Liang, Ying; Pan, Yingming; Guo, Qing; Hu, Hongzhi; Wu, Chancui; Zhang, Qian

    2015-01-01

    A novel fluorescent reagent for determination of ammonium, 4-methoxyphthalaldehyde (MOPA), was successfully synthesized in this study. Under alkaline conditions, MOPA could reacted with ammonium rapidly at room temperature, producing fluorescent substance which had maximum excitation at 370 nm and emission wavelength at 454 nm. Based on this, a novel fluorescence analysis method was established for the determination of trace ammonium in natural water. Experimental parameters including reagent...

  20. Using Iron-Manganese Co-Oxide Filter Film to Remove Ammonium from Surface Water

    Directory of Open Access Journals (Sweden)

    Ruifeng Zhang

    2017-07-01

    Full Text Available An iron-manganese co-oxide filter film (MeOx has been proven to be a good catalyst for the chemical catalytic oxidation of ammonium in groundwater. Compared with groundwater, surface water is generally used more widely and has characteristics that make ammonium removal more difficult. In this study, MeOx was used to remove ammonium from surface water. It indicated that the average ammonium removal efficiency of MeOx was greater than 90%, even though the water quality changed dramatically and the water temperature was reduced to about 6–8 °C. Then, through inactivating microorganisms, it showed that the removal capability of MeOx included both biological (accounted for about 41.05% and chemical catalytic oxidation and chemical catalytic oxidation (accounted for about 58.95%. The investigation of the characterizations suggested that MeOx was formed by abiotic ways and the main elements on the surface of MeOx were distributed homogenously. The analysis of the catalytic oxidation process indicated that ammonia nitrogen may interact with MeOx as both ammonia molecules and ammonium ions and the active species of O2 were possibly •O and O2−.

  1. Injectable ammonium chloride used enterally for the treatment of persistent metabolic alkalosis in three pediatric patients.

    Science.gov (United States)

    Mathew, Jennie T; Bio, Laura L

    2012-01-01

    Enteral administration of injectable ammonium chloride may offer an effective method for the treatment of persistent metabolic alkalosis, without the adverse effects associated with the intravenous route. This case series describes 3 pediatric patients who received ammonium chloride enterally for the treatment of persistent metabolic alkalosis. The patients were a 2-month-old female infant, a 6-week-old male infant, and a 3-year-old male toddler. Four to 18 doses of ammonium chloride were administered enterally (range, 3-144 mEq/dose). Two of the 3 patients achieved resolution of metabolic alkalosis with ammonium chloride, while 1 patient's condition was refractory to treatment. Resolution of metabolic alkalosis occurred at 4 and 8 days, which required a total weight-based dose of 10.7 mEq/kg and 18 mEq/kg, respectively. No adverse effects were recorded. The use of ammonium chloride injection administered enterally was a safe and effective option in 2 of the 3 pediatric patients with persistent metabolic alkalosis.

  2. Influence on ammonium-sulphate fertilizer on P-uptake by upland rice

    International Nuclear Information System (INIS)

    Abdullah, N; Mitrosuhardjo, M.M.

    1988-01-01

    A greenhouse experiment to study the influence of ammonium -sulphate fertilizer on P-uptake by Atomita I/1 rice variety on latosol soil of Pasar Jumat has been conducted. Factorial experiment consisting of eight treatments was arrange in a fully randomized design. Each treatment was replicated three times. The rate of ammonium sulphate fertilizer was equivalent to 0, 30, 60, and 90 kg N/ha, and TSP at the rate of 90 and 180 kg P/ha. Ammonium sulphate fertilizer with 2% atom 15-N and TSP with specific activity of 0.2 mCi/g P2O5 were used in the experiment. The plant was harvested 70 days after planting, It was turned out that ammonium sulphate fertilizer gave a highly significant difference (p=<0.01) of dry weight of plant. The rate of TSP did not effect significantly on plant dry weight. Ammonium sulphate fertilizer gave highly significant difference on P-uptake. Fertilizer use efficiency was in the range of 3.88 - 6.60% for 90 kg P and 2.51 - 4.46% for 180 kg P. Fertilizer-N uptake was significantly increased (p=<0.05) with the increase of N rate. Rate of fertilizer-N use efficiency was in the range of 47-60% of the applied fertilizer. (authors). 4 refs, 9 tabs

  3. Metal extraction from alum shale ashes under the effect of ammonium sulphate

    International Nuclear Information System (INIS)

    Maremaee, E.; Taal, H.

    1991-01-01

    The present study is a part of complex research about alum shale ashes carried out in the Institute of Chemistry of the Estonian Academy of Sciences during the period 1960-1975. In this paper the results of a research into decomposition of alum shale ashes under the effect of ammonium sulphate are presented. The following parameters of decomposition process were studied: temperature, time, quantity of ammonium sulphate needed for decomposition of ashes, In addition the effect of ammonium sulphate on the process of alum shale ashes thermal decomposition was studied using thermal methods. The optimum conditions determined for decomposition of ashes with ammonium sulphate were the following: temperature - 440 degrees by Celsius, duration -30 min., weight ratio of ammonium sulphate and ashes in reaction mixture -1.75 : 1. These data are confirmed by the results of thermal analysis. The above-mentioned process conditions guarantee the extraction of Ti, Mo, V, U and Fe about 70-85%, Al - up to 50%. 7 refs., 2 figs

  4. DNA amplification fingerprinting using 10 x polymerase chain reaction buffer with ammonium sulfate for human identification.

    Science.gov (United States)

    Baransel, Aysun; Dulger, Hikmet E; Tokdemir, Mehmet

    2004-06-01

    The polymerase chain reaction (PCR) - based DNA amplification fingerprinting (DAF) or randomly amplified polymorphic DNA (RAPD) is based on a strategy using a single arbitrary oligonucleotide primer to generate anonymous amplification of genomic DNA. On this basic strategy, in this study, we aimed to test individual differences and usefulness of 2 basic primers (5'-CGCGCCGG-3' and 5'-TGCCGAGCTG-3') and examined whether there is a positive effect on results of 10 x PCR buffer with ammonium sulfate. A new approach in DNA fingerprinting, 10 x PCR buffer with ammonium sulfate, is presented in the study. Primers with single 8 and 10 nucleotides in length and 2 different PCR buffers with or without ammonium sulfate were used to identify 135 volunteers with no blood relationship. This study was carried out at the Pharmacology Laboratory, University of Gaziantep, School of Medicine, Turkey between 1999 and 2000. An average of 10 major bands representing 500-1500 base pair (bp) in length was determined as amplified DNA products on standard agarose gels for these volunteers. The use of ammonium sulfate in 10 x PCR buffers has increased to 92% success ratio of individual difference obtained from the 8 nucleotides primer. With this study, more reliable results can be obtained by using ammonium sulfate in 10 x PCR buffers.

  5. Understanding the impact of the central atom on the ionic liquid behavior: Phosphonium vs ammonium cations

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Pedro J.; Ventura, Sónia P. M.; Batista, Marta L. S.; Schröder, Bernd; Coutinho, João A. P., E-mail: jcoutinho@ua.pt [CICECO, Departamento de Química, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Gonçalves, Fernando [Departamento de Biologia e CESAM (Centro de Estudos do Ambiente e do Mar), Universidade de Aveiro, 3810-193 Aveiro (Portugal); Esperança, José [Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, 2780-901 Oeiras (Portugal); Mutelet, Fabrice [Laboratoire Réactions et Génie des Procédés, CNRS (UPR3349), Nancy-Université, 1 rue Grandville, BP 20451 54001 Nancy (France)

    2014-02-14

    The influence of the cation's central atom in the behavior of pairs of ammonium- and phosphonium-based ionic liquids was investigated through the measurement of densities, viscosities, melting temperatures, activity coefficients at infinite dilution, refractive indices, and toxicity against Vibrio fischeri. All the properties investigated are affected by the cation's central atom nature, with ammonium-based ionic liquids presenting higher densities, viscosities, melting temperatures, and enthalpies. Activity coefficients at infinite dilution show the ammonium-based ionic liquids to present slightly higher infinite dilution activity coefficients for non-polar solvents, becoming slightly lower for polar solvents, suggesting that the ammonium-based ionic liquids present somewhat higher polarities. In good agreement these compounds present lower toxicities than the phosphonium congeners. To explain this behavior quantum chemical gas phase DFT calculations were performed on isolated ion pairs at the BP-TZVP level of theory. Electronic density results were used to derive electrostatic potentials of the identified minimum conformers. Electrostatic potential-derived CHelpG and Natural Population Analysis charges show the P atom of the tetraalkylphosphonium-based ionic liquids cation to be more positively charged than the N atom in the tetraalkylammonium-based analogous IL cation, and a noticeable charge delocalization occurring in the tetraalkylammonium cation, when compared with the respective phosphonium congener. It is argued that this charge delocalization is responsible for the enhanced polarity observed on the ammonium based ionic liquids explaining the changes in the thermophysical properties observed.

  6. An Electronic Tongue Designed to Detect Ammonium Nitrate in Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Inmaculada Campos

    2013-10-01

    Full Text Available An electronic tongue has been developed to monitor the presence of ammonium nitrate in water. It is based on pulse voltammetry and consists of an array of eight working electrodes (Au; Pt; Rh; Ir; Cu; Co; Ag and Ni encapsulated in a stainless steel cylinder. In a first step the electrochemical response of the different electrodes was studied in the presence of ammonium nitrate in water in order to further design the wave form used in the voltammetric tongue. The response of the electronic tongue was then tested in the presence of a set of 15 common inorganic salts; i.e.; NH4NO3; MgSO4; NH4Cl; NaCl; Na2CO3; (NH42SO4; MgCl2; Na3PO4; K2SO4; K2CO3; CaCl2; NaH2PO4; KCl; NaNO3; K2HPO4. A PCA plot showed a fairly good discrimination between ammonium nitrate and the remaining salts studied. In addition Fuzzy Art map analyses determined that the best classification was obtained using the Pt; Co; Cu and Ni electrodes. Moreover; PLS regression allowed the creation of a model to correlate the voltammetric response of the electrodes with concentrations of ammonium nitrate in the presence of potential interferents such as ammonium chloride and sodium nitrate.

  7. DNA amplification fingerprinting using 10 x polymerase chain reaction buffer with ammonium sulfate for human identification

    International Nuclear Information System (INIS)

    Baransel, Asyun; Dugler, Hikmat E.; Tokdemir, Mehmet

    2004-01-01

    The polymerase chain reaction (PCR) - based DNA amplification fingerprinting (DAF) or randomly amplified polymorphic DNA (RAPD) is based on a strategy using a single arbitrary oligonucleotide primer to generate anonymous amplification of genomic DNA. On this basic strategy, in this study, we aimed to test individual differences and usefulness of 2 basic primers (5-CGCGCCGG-3 and 5-TGCCGAGCTG-3) and examined whether there is a positive effect on results of 10 x PCR buffer with ammonium sulfate. A new approach in DNA fingerprinting, 10 x PCR buffer with ammonium sulfate, is presented in the study. Primers with single 8 and 10 nucleotides in length and 2 different PCR buffers with or without ammonium sulfate were used to identify 135 volunteers with no blood relationship. This study was carried out at the Pharmacology Laboratory, University of Gaziantep, School of Medicine, Turkey between 1999 and 2000. An average of 10 major bands representing 500-1500 base pair (bp) in length was determined as amplified DNA products on standard agarose gels for these volunteers. The use of ammonium sulfate in 10 x PCR buffers has increased to 92% success ratio of individual difference obtained from the 8 nucleotides primer. With this study, more reliable results can be obtained by using ammonium sulfate in 10 x PCR buffers. (author)

  8. Effect of application approaches of ammonium bicarbonate on yield of spring wheat and nitrogen balance

    International Nuclear Information System (INIS)

    Wen Xianfang; Pan Jiarong; Zheng Xingyun

    1995-01-01

    The results from 15 N-tracing experiment showed that at the same rate of nitrogen application, the nitrogen utilization ammonium bicarbonate was 33.50%, 32.30% and 23.19% respectively and the nitrogen loss rate of ammonium bicarbonate was 22.12%, 26.93% and 45.32% respectively for fertilizer mixed thoroughly with soil before sowing, buried into soil and spread on the surface of soil at both joining stage (1/2N) and booting stage (1/2N) of spring wheat. The nitrogen utilization of ammonium bicarbonate for top-application at both joining (1/2N) and booting stage (1/2N) was significantly lower but nitrogen loss rate was significantly higher than that of either thorough incorporation with soil or deep application at joining and booting stages. Between the latter treatments there was no significantly difference observed. There was no significant difference in biomass and grain yield of spring wheat between the former treatment and either of the latter treatments, indicating that buried into soil or mixed with soil thoroughly as a basal fertilizer was an available approach to increase the nitrogen availability of ammonium bicarbonate and crop yield. It was also shown that no significant difference in biomass and grain yield of spring wheat between deep application of ammonium bicarbonate and top-application of urea at the same rate of N application

  9. Evaluation of natural zeolite clinoptilolite efficiency for the removal of ammonium and nitrate from aquatic solutions

    Directory of Open Access Journals (Sweden)

    Mozhdeh Murkani

    2015-01-01

    Full Text Available Background: Surface water and groundwater pollution with various forms of nitrogen such as ammonium and nitrate ions is one of the main environmental risks. The major objectives of this study were to evaluate the capacity of natural zeolite (clinoptilolite to remove NO3– and NH4+ from polluted water under both batch and column conditions. Methods: The laboratory batch and column experiments were conducted to investigate the feasibility of clinoptilolite as the adsorbent for removal of nitrate (NO3– and ammonium (NH4+ ions from aqueous solution. The effects of pH, clinoptilolite dosage, contact time, and initial metal ion concentration on NO3– and NH4+ removal were investigated in a batch system. Results: Equilibrium time for NO3– and NH4+ ions exchange was 60 minutes and the optimum adsorbent dosage for their removal was 1 and 2.5 g/L, respectively. The adsorption isotherm of reaction (r> 0.9 and optimum entered concentration of ammonium and nitrate (30 and 6.5 mg/L, respectively were in accordance with Freundlich isotherm model. The ammonium removal rate increased by 98% after increasing the contact time. Conclusion: Our findings confirmed that natural Clinoptilolite can be used as one of effective, suitable, and low-costing adsorbent for removing ammonium from polluted waters.

  10. Volatility of organic aerosol: evaporation of ammonium sulfate/succinic acid aqueous solution droplets.

    Science.gov (United States)

    Yli-Juuti, Taina; Zardini, Alessandro A; Eriksson, Axel C; Hansen, Anne Maria K; Pagels, Joakim H; Swietlicki, Erik; Svenningsson, Birgitta; Glasius, Marianne; Worsnop, Douglas R; Riipinen, Ilona; Bilde, Merete

    2013-01-01

    Condensation and evaporation modify the properties and effects of atmospheric aerosol particles. We studied the evaporation of aqueous succinic acid and succinic acid/ammonium sulfate droplets to obtain insights on the effect of ammonium sulfate on the gas/particle partitioning of atmospheric organic acids. Droplet evaporation in a laminar flow tube was measured in a Tandem Differential Mobility Analyzer setup. A wide range of droplet compositions was investigated, and for some of the experiments the composition was tracked using an Aerosol Mass Spectrometer. The measured evaporation was compared to model predictions where the ammonium sulfate was assumed not to directly affect succinic acid evaporation. The model captured the evaporation rates for droplets with large organic content but overestimated the droplet size change when the molar concentration of succinic acid was similar to or lower than that of ammonium sulfate, suggesting that ammonium sulfate enhances the partitioning of dicarboxylic acids to aqueous particles more than currently expected from simple mixture thermodynamics. If extrapolated to the real atmosphere, these results imply enhanced partitioning of secondary organic compounds to particulate phase in environments dominated by inorganic aerosol.

  11. Evaluation of quaternary ammonium halides for removal of methyl iodide from flowing air streams

    International Nuclear Information System (INIS)

    Freeman, W.P.; Mohacsi, T.G.; Kovach, J.L.

    1985-01-01

    The quaternary ammonium halides of several tertiary amines were used as impregnants on activated carbon and were tested for methyl iodide penetration in accordance with test Method A, ASTM D3803, 1979, ''Standard Test Methods for Radio-iodine Testing of Nuclear Grade Gas Phase Adsorbents''. The results suggest that the primary removal mechanism for methyl iodide-131 is isotopic exchange with the quaternary ammonium halide. For example, a 5 wt% impregnation of each of the tetramethyl, tetraethyl, tetrapropyl and tetrabutyl ammonium iodides on activated carbon yielded percent penetrations of 0.47, 0.53, 0.78, and 0.08 respectively when tested according to Method A of ASTM D3803. A sample impregnated with 5% tetramethyl ammonium hydroxide gave a methyl iodide penetration of 64.87%, thus supporting the isotopic exchange mechanism for removal. It has been a generally held belief that the success of tertiary amines as impregnants for radioiodine removal is a result of their ability to complex with the methyl iodide. The results of the work indicates that the superiority of the tertiary amines similar to triethylene diamine and quinuclidine, when compared to their straight chain analogs, is a result of their ease in reacting with methyl iodide-127 to form the quaternary ammonium iodide followed by isotopic exchange

  12. Aluminium tolerance in rice is antagonistic with nitrate preference and synergistic with ammonium preference.

    Science.gov (United States)

    Zhao, Xue Qiang; Guo, Shi Wei; Shinmachi, Fumie; Sunairi, Michio; Noguchi, Akira; Hasegawa, Isao; Shen, Ren Fang

    2013-01-01

    Acidic soils are dominated chemically by more ammonium and more available, so more potentially toxic, aluminium compared with neutral to calcareous soils, which are characterized by more nitrate and less available, so less toxic, aluminium. However, it is not known whether aluminium tolerance and nitrogen source preference are linked in plants. This question was investigated by comparing the responses of 30 rice (Oryza sativa) varieties (15 subsp. japonica cultivars and 15 subsp. indica cultivars) to aluminium, various ammonium/nitrate ratios and their combinations under acidic solution conditions. indica rice plants were generally found to be aluminium-sensitive and nitrate-preferring, while japonica cultivars were aluminium-tolerant and relatively ammonium-preferring. Aluminium tolerance of different rice varieties was significantly negatively correlated with their nitrate preference. Furthermore, aluminium enhanced ammonium-fed rice growth but inhibited nitrate-fed rice growth. The results suggest that aluminium tolerance in rice is antagonistic with nitrate preference and synergistic with ammonium preference under acidic solution conditions. A schematic diagram summarizing the interactions of aluminium and nitrogen in soil-plant ecosystems is presented and provides a new basis for the integrated management of acidic soils.

  13. Volatility of Organic Aerosol: Evaporation of Ammonium Sulfate/Succinic Acid Aqueous Solution Droplets

    Science.gov (United States)

    2013-01-01

    Condensation and evaporation modify the properties and effects of atmospheric aerosol particles. We studied the evaporation of aqueous succinic acid and succinic acid/ammonium sulfate droplets to obtain insights on the effect of ammonium sulfate on the gas/particle partitioning of atmospheric organic acids. Droplet evaporation in a laminar flow tube was measured in a Tandem Differential Mobility Analyzer setup. A wide range of droplet compositions was investigated, and for some of the experiments the composition was tracked using an Aerosol Mass Spectrometer. The measured evaporation was compared to model predictions where the ammonium sulfate was assumed not to directly affect succinic acid evaporation. The model captured the evaporation rates for droplets with large organic content but overestimated the droplet size change when the molar concentration of succinic acid was similar to or lower than that of ammonium sulfate, suggesting that ammonium sulfate enhances the partitioning of dicarboxylic acids to aqueous particles more than currently expected from simple mixture thermodynamics. If extrapolated to the real atmosphere, these results imply enhanced partitioning of secondary organic compounds to particulate phase in environments dominated by inorganic aerosol. PMID:24107221

  14. SAFARI 2000 GPCP Daily Precipitation, 1-Deg, 1999-2001

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: The Global Precipitation Climatology Project (GPCP) is an international project designed to provide improved long-record estimates of precipitation over...

  15. GPM GROUND VALIDATION PRECIPITATION VIDEO IMAGER (PVI) GCPEX V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GPM Ground Validation Precipitation Video Imager (PVI) GCPEx dataset collected precipitation particle images and drop size distribution data from November 2011...

  16. Global Precipitation Measurement (GPM) Mission: Precipitation Processing System (PPS) GPM Mission Gridded Text Products Provide Surface Precipitation Retrievals

    Science.gov (United States)

    Stocker, Erich Franz; Kelley, O.; Kummerow, C.; Huffman, G.; Olson, W.; Kwiatkowski, J.

    2015-01-01

    In February 2015, the Global Precipitation Measurement (GPM) mission core satellite will complete its first year in space. The core satellite carries a conically scanning microwave imager called the GPM Microwave Imager (GMI), which also has 166 GHz and 183 GHz frequency channels. The GPM core satellite also carries a dual frequency radar (DPR) which operates at Ku frequency, similar to the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar, and a new Ka frequency. The precipitation processing system (PPS) is producing swath-based instantaneous precipitation retrievals from GMI, both radars including a dual-frequency product, and a combined GMIDPR precipitation retrieval. These level 2 products are written in the HDF5 format and have many additional parameters beyond surface precipitation that are organized into appropriate groups. While these retrieval algorithms were developed prior to launch and are not optimal, these algorithms are producing very creditable retrievals. It is appropriate for a wide group of users to have access to the GPM retrievals. However, for researchers requiring only surface precipitation, these L2 swath products can appear to be very intimidating and they certainly do contain many more variables than the average researcher needs. Some researchers desire only surface retrievals stored in a simple easily accessible format. In response, PPS has begun to produce gridded text based products that contain just the most widely used variables for each instrument (surface rainfall rate, fraction liquid, fraction convective) in a single line for each grid box that contains one or more observations.This paper will describe the gridded data products that are being produced and provide an overview of their content. Currently two types of gridded products are being produced: (1) surface precipitation retrievals from the core satellite instruments GMI, DPR, and combined GMIDPR (2) surface precipitation retrievals for the partner constellation

  17. Differential expression of Aspergillus nidulans ammonium permease genes is regulated by GATA transcription factor AreA.

    Science.gov (United States)

    Monahan, Brendon J; Askin, Marion C; Hynes, Michael J; Davis, Meryl A

    2006-02-01

    The movement of ammonium across biological membranes is mediated in both prokaryotes and eukaryotes by ammonium transport proteins (AMT/MEP) that constitute a family of related sequences. We have previously identified two ammonium permeases in Aspergillus nidulans, encoded by the meaA and mepA genes. Here we show that meaA is expressed in the presence of ammonium, consistent with the function of MeaA as the main ammonium transporter required for optimal growth on ammonium as a nitrogen source. In contrast, mepA, which encodes a high-affinity ammonium permease, is expressed only under nitrogen-limiting or starvation conditions. We have identified two additional AMT/MEP-like genes in A. nidulans, namely, mepB, which encodes a second high-affinity ammonium transporter expressed only in response to complete nitrogen starvation, and mepC, which is expressed at low levels under all nitrogen conditions. The MepC gene product is more divergent than the other A. nidulans AMT/MEP proteins and is not thought to significantly contribute to ammonium uptake under normal conditions. Remarkably, the expression of each AMT/MEP gene under all nitrogen conditions is regulated by the global nitrogen regulatory GATA factor AreA. Therefore, AreA is also active under nitrogen-sufficient conditions, along with its established role as a transcriptional activator in response to nitrogen limitation.

  18. Struvite Precipitation and Phosphorous Removal from Urine Synthetic Solution: Reaction Kinetic Study

    Directory of Open Access Journals (Sweden)

    Marwa Saied Shalaby

    2015-03-01

    Full Text Available Phosphorus, like oil, is a non-renewable resource that must be harvested from finite resources in the earth’s crust. An essential element for life, phosphorus is becoming increasingly scarce, contaminated, and difficult to extract. Struvite or magnesium ammonium phosphate (MgNH4PO4.6H2O is a white, crystalline phosphate mineral that can be used as a bio-available fertilizer. The main objective of this research is to indicate the most important operating parameters affecting struvite precipitation by means of chemical reaction kinetics. The present study explores struvite precipitation by chemical method under different starting molar ratios, pH and SSR. It is shown that an increase of starting Mg: PO4: NH4 with respect to magnesium (1.6:1:1 strongly influences the growth rate of struvite and so the efficiency of the phosphate removal. This was attributed to the effect of magnesium on the struvite solubility product and on the reached supersaturation Super Saturation Ratio at optimum starting molar ratio and pH. It was also shown, by using chemical precipitation method that the determined Super Saturation Ratio (SSR values of struvite, at 8, 8.5, 9, 9.5 and 10 are 1.314, 4.29, 8.89, 9.87 and 14.89 respectively are close to those presented in the literature for different origins of wastewater streams. The results show that SSR , pH, and starting molar ratio strongly influences the kinetics of precipitation and so phosphorous removal to reach 93% removal percent , 5.95 mg/lit as a minimum PO4 remained in solution, and 7.9 gm precipitated struvite from feed synthetic solution of 750 ml . The product was subjected to chemical analysis by means of EDIX-FTIR, SEM and XRD showing conformity with published literature. First-order kinetics was found to be sufficient to describe the rate data. The rates increased with increasing pH and so SSR and the apparent rate constants for the reaction were determined. © 2015 BCREC UNDIP. All rights reserved

  19. Structures of Tris(2-hydroxyethyl)ammonium Salts of Succinic Acid

    Science.gov (United States)

    Loginov, S. V.; Dain, I. A.; Rybakov, V. B.; Ofitserov, E. N.; Gordeev, D. A.; Storozhenko, P. A.

    2018-01-01

    Succinic acid salts-tris(2-hydroxyethyl)ammonium succinate (C6H16NO3) 2 + C4H4O 4 2- (monoclinic crystals, sp. gr. P21/ c, Z = 4) and tris(2-hydroxyethyl)ammonium hydrogen succinate (C6H16NO3)+C4H5O 4 - (monoclinic crystals, sp. gr. P21/ c, Z = 4)—were synthesized and structurally characterized. The specific features of the three-dimensional structures of tris(2-hydroxyethyl)ammonium salts of succinic acid are considered. The role of interionic electrostatic interactions in the structure stabilization and the formation of products of composition 1: 1 and 1: 2 derived from succinic acid is discussed.

  20. Detoxification of ammonium to Nannochloropsis oculata and enhancement of lipid production by mixotrophic growth with acetate.

    Science.gov (United States)

    Lin, Weitie; Li, Pengfei; Liao, Zipeng; Luo, Jianfei

    2017-03-01

    In this study, the toxicity of ammonium was removed in the microalga Nannochloropsis oculata by using acetate as a carbon source. Algal biomass and lipid production were significantly enhanced when N. oculata was grew on 0.5-50mM of ammonium and 16-64mM of acetate in mixotrophic conditions. When grown mixotrophically on 1mM of ammonium and 32mM of acetate, the biomass and lipid production reached 543mg/L and 279mg/L respectively, which were 1.5 and 9.4times higher than the levels generated when grown autotrophically on nitrate. This suggests that mixotrophic growth with acetate can be a useful method to enhance microalgal lipid production. Copyright © 2016 Elsevier Ltd. All rights reserved.