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Sample records for ammonia borane compound

  1. Hydrogen production using ammonia borane

    Science.gov (United States)

    Hamilton, Charles W; Baker, R. Thomas; Semelsberger, Troy A; Shrestha, Roshan P

    2013-12-24

    Hydrogen ("H.sub.2") is produced when ammonia borane reacts with a catalyst complex of the formula L.sub.nM-X wherein M is a base metal such as iron, X is an anionic nitrogen- or phosphorus-based ligand or hydride, and L is a neutral ancillary ligand that is a neutral monodentate or polydentate ligand.

  2. Regeneration of ammonia borane from polyborazylene

    Science.gov (United States)

    Sutton, Andrew; Gordon, John C; Ott, Kevin C; Burrell, Anthony K

    2013-02-05

    Method of producing ammonia borane, comprising providing a reagent comprising a dehydrogenated material in a suitable solvent; and combining the reagent with a reducing agent comprising hydrazine, a hydrazine derivative, or combinations thereof, in a reaction which produces a mixture comprising ammonia borane.

  3. Method for releasing hydrogen from ammonia borane

    Science.gov (United States)

    Varma, Arvind; Diwan, Moiz; Shafirovich, Evgeny; Hwang, Hyun-Tae; Al-Kukhun, Ahmad

    2013-02-19

    A method of releasing hydrogen from ammonia borane is disclosed. The method comprises heating an aqueous ammonia borane solution to between about 80-135.degree. C. at between about 14.7 and 200 pounds per square inch absolute (psia) to release hydrogen by hydrothermolysis.

  4. Chemical Hydrogen Storage Using Polyhedral Borane Anions and Aluminum-Ammonia-Borane Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Hawthorne, M. Frederick; Jalisatgi, Satish S.; Safronov, Alexander V.; Lee, Han Beak; Wu, Jianguo

    2010-10-01

    Phase 1. Hydrolysis of borohydride compounds offer the potential for significant hydrogen storage capacity, but most work to date has focused on one particular anion, BH4-, which requires high pH for stability. Other borohydride compounds, in particular polyhedral borane anions offer comparable hydrogen storage capacity without requiring high pH media and their long term thermal and hydrolytic stability coupled with non-toxic nature make them a very attractive alternative to NaBH4. The University of Missouri project provided the overall program focal point for the investigation of catalytic hydrolysis of polyhedral borane anions for hydrogen release. Due to their inherent stability, a transition metal catalyst was necessary for the hydrolysis of polyhedral borane anions. Transition metal ions such as cobalt, nickel, palladium and rhodium were investigated for their catalytic activity in the hydrolysis of nido-KB11H14, closo-K2B10H10, and closo-K2B12H12. The rate of hydrolysis follows first-order kinetics with respect to the concentration of the polyhedral borane anion and surface area of the rhodium catalyst. The rate of hydrolysis depends upon a) choice of polyhedral borane anion, c) concentration of polyhedral borane anion, d) surface area of the rhodium catalyst and e) temperature of the reaction. In all cases the yield of hydrogen was 100% which corresponds to ~7 wt% of hydrogen (based on material wt%). Phase 2. The phase 2 of program at the University of Missouri was focused upon developing aluminum ammonia-boranes (Al-AB) as chemical hydrogen storage materials, specifically their synthesis and studies of their dehydrogenation. The ammonia borane molecule (AB) is a demonstrated source of chemically stored hydrogen (19.6 wt%) which meets DOE performance parameters except for its regeneration from spent AB and elemental hydrogen. The presence of an aluminum center bonded to multiple AB residues might combine the efficiency of AB dehydrogenation with an aluminum

  5. Procedures for the synthesis of ethylenediamine bisborane and ammonia borane

    Energy Technology Data Exchange (ETDEWEB)

    Ramachandran, Padi Veeraraghavan; Gagare, Pravin D.; Mistry, Hitesh; Biswas, Bidyut

    2017-01-03

    A method for synthesizing ammonia borane includes (a) preparing a reaction mixture in one or more solvents, the reaction mixture containing sodium borohydride, at least one ammonium salt, and ammonia; and (b) incubating the reaction mixture at temperatures between about 0.degree. C. to about room temperature in an ambient air environment under conditions sufficient to form ammonia borane. Methods for synthesizing ethylenediamine bisborane, and methods for dehydrogenation of ethylenediamine bisborane are also described.

  6. Hydrazine borane-induced destabilization of ammonia borane, and vice versa

    Energy Technology Data Exchange (ETDEWEB)

    Petit, Jean-Fabien; Moussa, Georges [IEM (Institut Europeen des Membranes), UMR 5635 (CNRS-ENSCM-UM2), Universite Montpellier 2, Place E. Bataillon, F-34095 Montpellier (France); Demirci, Umit B., E-mail: umit.demirci@um2.fr [IEM (Institut Europeen des Membranes), UMR 5635 (CNRS-ENSCM-UM2), Universite Montpellier 2, Place E. Bataillon, F-34095 Montpellier (France); Toche, François; Chiriac, Rodica [Université Lyon 1, CNRS, UMR 5615, Laboratoire des Multimatériaux et Interfaces, 43 boulevard du 11 Novembre 1918, F-69622 Villeurbanne (France); Miele, Philippe [IEM (Institut Europeen des Membranes), UMR 5635 (CNRS-ENSCM-UM2), Universite Montpellier 2, Place E. Bataillon, F-34095 Montpellier (France)

    2014-08-15

    Graphical abstract: - Highlights: • Hydrazine borane and ammoniaborane (mole ratio 1:1) destabilize each other. • This is characterized by a melting point at ∼30 °C and decomposition into hydrazine. • Also, some hydrogen H{sub 2} is “explosively” liberated at around 90 °C. • The mixture can be however stabilized into a potential hydrogen storage material. • This hydrogen storage material dehydrogenates up to 300 °C to form boron nitride. - Abstract: In the field of solid-state chemical hydrogen storage, ammonia borane NH{sub 3}BH{sub 3} has been widely studied while hydrazine borane N{sub 2}H{sub 4}BH{sub 3} can be considered as a “novel” material. In the present work, we investigated the behaviour of these boranes when mixed together in a mole ratio of 1:1. Hydrazine borane and ammonia borane destabilize each other. Though stable at 20–25 °C, the mixture melts at ∼30 °C and then undergoes significant decomposition, with desorption of hydrogen H{sub 2} and hydrazine N{sub 2}H{sub 4} from 67 °C. This is explained by the fact that the presence of hydrazine borane disrupts the H{sup δ+}⋯H{sup δ−} network of ammonia borane, and vice versa; the mixture is then much less stable than the pristine boranes. The mixture can nevertheless be stabilized (by heat- or vacuum-treatment and thus extraction of evolving hydrogen and hydrazine), making the as-obtained solid a potential chemical hydrogen storage material. Over the range 25–300 °C, it is able to release ca. 11.4 wt% of almost pure H{sub 2}. Furthermore forms boron nitride as the solid residue, at temperatures as low as 300 °C.

  7. Hydrolysis of ammonia borane as a hydrogen source: fundamental issues and potential solutions towards implementation.

    Science.gov (United States)

    Sanyal, Udishnu; Demirci, Umit B; Jagirdar, Balaji R; Miele, Philippe

    2011-12-16

    In today's era of energy crisis and global warming, hydrogen has been projected as a sustainable alternative to depleting CO(2)-emitting fossil fuels. However, its deployment as an energy source is impeded by many issues, one of the most important being storage. Chemical hydrogen storage materials, in particular B-N compounds such as ammonia borane, with a potential storage capacity of 19.6 wt % H(2) and 0.145 kg(H2)L(-1), have been intensively studied from the standpoint of addressing the storage issues. Ammonia borane undergoes dehydrogenation through hydrolysis at room temperature in the presence of a catalyst, but its practical implementation is hindered by several problems affecting all of the chemical compounds in the reaction scheme, including ammonia borane, water, borate byproducts, and hydrogen. In this Minireview, we exhaustively survey the state of the art, discuss the fundamental problems, and, where applicable, propose solutions with the prospect of technological applications.

  8. Ammonia-Borane and Amine-Borane Dehydrogenation Mediated by Complex Metal Hydrides.

    Science.gov (United States)

    Rossin, Andrea; Peruzzini, Maurizio

    2016-08-10

    This review is a comprehensive survey of the last 10 years of research on ammonia-borane and amine-borane dehydrogenation mediated by complex metal hydrides (CMHs), within the broader context of chemical hydrogen storage. The review also collects those cases where CMHs are the catalyst spent form or its resting state. Highlights on the reaction mechanism (strictly dependent on the CMH of choice) and the catalysts efficiency (in terms of equivalents of H2 produced and relative reaction rates) are provided throughout the discussion.

  9. Transition metal catalysed ammonia-borane dehydrogenation in ionic liquids.

    Science.gov (United States)

    Wright, William R H; Berkeley, Emily R; Alden, L R; Baker, R Tom; Sneddon, Larry G

    2011-03-21

    Significant advantages result from combining the disparate hydrogen release pathways for ammonia-borane (AB) dehydrogenation using ionic liquids (ILs) and transition metal catalysts. With the RuCl(2)(PMe(3))(4) catalyst precursor, AB dehydrogenation selectivity and extent are maximized in an IL with a moderately coordinating ethylsulfate anion.

  10. Process for synthesis of ammonia borane for bulk hydrogen storage

    Science.gov (United States)

    Autrey, S Thomas [West Richland, WA; Heldebrant, David J [Richland, WA; Linehan, John C [Richland, WA; Karkamkar, Abhijeet J [Richland, WA; Zheng, Feng [Richland, WA

    2011-03-01

    The present invention discloses new methods for synthesizing ammonia borane (NH.sub.3BH.sub.3, or AB). Ammonium borohydride (NH.sub.4BH.sub.4) is formed from the reaction of borohydride salts and ammonium salts in liquid ammonia. Ammonium borohydride is decomposed in an ether-based solvent that yields AB at a near quantitative yield. The AB product shows promise as a chemical hydrogen storage material for fuel cell powered applications.

  11. Liquid composition having ammonia borane and decomposing to form hydrogen and liquid reaction product

    Science.gov (United States)

    Davis, Benjamin L; Rekken, Brian D

    2014-04-01

    Liquid compositions of ammonia borane and a suitably chosen amine borane material were prepared and subjected to conditions suitable for their thermal decomposition in a closed system that resulted in hydrogen and a liquid reaction product.

  12. Rotational dynamics in ammonia borane: Evidence of strong isotope effects

    Energy Technology Data Exchange (ETDEWEB)

    Cantelli, Rosario; Paolone, Annalisa; Palumbo, Oriele; Leardini, F.; Autrey, Thomas; Karkamkar, Abhijeet J.; Luedtke, Avery T.

    2013-12-15

    This work reports anelastic spectroscopy measurements on the partially deuterated (ND3BH3 and NH3BD3) and perdeuterated (ND3BD3) ammonia borane (NH3BH3) compounds. The relaxations previously reported in NH3BH3 are observed in all the samples, and are ascribed to the rotational and torsional dynamics of NH(D)3BH(D)3 complexes. A new thermally activated peak appears at 70 K (for a vibration frequency of 1 kHz) in the spectrum of NH3BD3 and ND3BD3. The peak is practically a single-time Debye process, indicating absence of interaction between the relaxing units, and has a strikingly high intensity. A secondary relaxation process is also detected around 55 K. The anelastic spectrum of the ND3BH3 only displays this less intense process at 55 K. The analysis of the peaks supplies information about the dynamics of the relaxing species, and the obtained results provide indications on the effect of partial and selective deuteration on the hydrogen (deuterium) dynamics.

  13. Syntheses and structural characterizations of anionic borane-capped ammonia borane oligomers: evidence for ammonia borane H2 release via a base-promoted anionic dehydropolymerization mechanism.

    Science.gov (United States)

    Ewing, William C; Marchione, Allegra; Himmelberger, Daniel W; Carroll, Patrick J; Sneddon, Larry G

    2011-10-26

    Studies of the activating effect of Verkade's base, 2,8,9-triisobutyl-2,5,8,9-tetraaza-1-phosphabicyclo[3.3.3]undecane (VB), on the rate and extent of H(2) release from ammonia borane (AB) have led to the syntheses and structural characterizations of three anionic aminoborane chain-growth products that provide direct support for anionic dehydropolymerization mechanistic steps in the initial stages of base-promoted AB H(2) release reactions. The salt VBH(+)[H(3)BNH(2)BH(2)NH(2)BH(3)](-) (1) containing a linear five-membered anionic aminoborane chain was produced in 74% yield via the room-temperature reaction of a 3:1 AB/VB mixture in fluorobenzene solvent, while the branched and linear-chain seven-membered anionic aminoborane oligomers VBH(+)[HB(NH(2)BH(3))(3)](-) (2a) and VBH(+)[H(3)BNH(2)BH(2)NH(2)BH(2)NH(2)BH(3)](-) (2b) were obtained from VB/AB reactions carried out at 50 °C for 5 days when the AB/VB ratio was increased to 4:1. X-ray crystal structure determinations confirmed that these compounds are the isoelectronic and isostructural analogues of the hydrocarbons n-pentane, 3-ethylpentane, and n-heptane, respectively. The structural determinations also revealed significant interionic B-H···H-N dihydrogen-bonding interactions in these anions that could enhance dehydrocoupling chain-growth reactions. Such mechanistic pathways for AB H(2) release, involving the initial formation of the previously known [H(3)BNH(2)BH(3)](-) anion followed by sequential dehydrocoupling of B-H and H-N groups of growing borane-capped aminoborane anions with AB, are supported by the fact that 1 was observed to react with an additional AB equivalent to form 2a and 2b.

  14. Ruthenium-Catalyzed Ammonia Borane Dehydrogenation: Mechanism and Utility.

    Science.gov (United States)

    Zhang, Xingyue; Kam, Lisa; Trerise, Ryan; Williams, Travis J

    2017-01-17

    One of the greatest challenges in using H2 as a fuel source is finding a safe, efficient, and inexpensive method for its storage. Ammonia borane (AB) is a solid hydrogen storage material that has garnered attention for its high hydrogen weight density (19.6 wt %) and ease of handling and transport. Hydrogen release from ammonia borane is mediated by either hydrolysis, thus giving borate products that are difficult to rereduce, or direct dehydrogenation. Catalytic AB dehydrogenation has thus been a popular topic in recent years, motivated both by applications in hydrogen storage and main group synthetic chemistry. This Account is a complete description of work from our laboratory in ruthenium-catalyzed ammonia borane dehydrogenation over the last 6 years, beginning with the Shvo catalyst and resulting ultimately in the development of optimized, leading catalysts for efficient hydrogen release. We have studied AB dehydrogenation with Shvo's catalyst extensively and generated a detailed understanding of the role that borazine, a dehydrogenation product, plays in the reaction: it is a poison for both Shvo's catalyst and PEM fuel cells. Through independent syntheses of Shvo derivatives, we found a protective mechanism wherein catalyst deactivation by borazine is prevented by coordination of a ligand that might otherwise be a catalytic poison. These studies showed how a bidentate N-N ligand can transform the Shvo into a more reactive species for AB dehydrogenation that minimizes accumulation of borazine. Simultaneously, we designed novel ruthenium catalysts that contain a Lewis acidic boron to replace the Shvo -OH proton, thus offering more flexibility to optimize hydrogen release and take on more general problems in hydride abstraction. Our scorpionate-ligated ruthenium species (12) is a best-of-class catalyst for homogeneous dehydrogenation of ammonia borane in terms of its extent of hydrogen release (4.6 wt %), air tolerance, and reusability. Moreover, a synthetically

  15. Efficient regeneration of partially spent ammonia borane fuel

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Benjamin Lee [Los Alamos National Laboratory; Gordon, John C [Los Alamos National Laboratory; Stephens, Frances [Los Alamos National Laboratory; Dixon, David A [UNIV OF ALABAMA; Matus, Myrna H [UNIV OF ALABAMA

    2008-01-01

    A necessary target in realizing a hydrogen (H{sub 2}) economy, especially for the transportation sector, is its storage for controlled delivery, presumably to an energy producing fuel cell. In this vein, the U.S. Department of Energy's (DOE) Centers of Excellence (CoE) in Hydrogen Storage have pursued different methodologies, including metal hydrides, chemical hydrides, and sorbents, for the expressed purpose of supplanting gasoline's current > 300 mile driving range. Chemical hydrogen storage has been dominated by one appealing material, ammonia borane (H{sub 3}B-NH{sub 3}, AB), due to its high gravimetric capacity of hydrogen (19.6 wt %) and low molecular weight (30.7 g mol{sup -1}). In addition, AB has both hydridic and protic moieties, yielding a material from which H2 can be readily released. As such, a number of publications have described H{sub 2} release from amine boranes, yielding various rates depending on the method applied. Even though the viability of any chemical hydrogen storage system is critically dependent on efficient recyclability, reports on the latter subject are sparse, invoke the use of high energy reducing agents, and suffer from low yields. For example, the DOE recently decided to no longer pursue the use of NaBH{sub 4} as a H{sub 2} storage material, in part because of inefficient regeneration. We thus endeavored to find an energy efficient regeneration process for the spent fuel from H{sub 2} depleted AB with a minimum number of steps.

  16. Hydrogen Generation from Ammonia Borane and Water Through the Combustion Reactions with Mechanically Alloyed Al/Mg Powder

    Science.gov (United States)

    2014-08-11

    synthesis of ammonia -A ‘‘never ending story? " Angewandte...34 # && , (/ -%(/ &$’$) ) ! -( ( !( &" # ( %’ !&% # ’)( (% (" %’% (" ( & *%" # ’)( *! % + 3 HYDROGEN GENERATION FROM AMMONIA BORANE AND WATER THROUGH THE...FROM AMMONIA BORANE AND WATER THROUGH THE COMBUSTION REACTIONS WITH MECHANICALLY ALLOYED AL/MG POWDER by DANIEL RODRIGUEZ THESIS Presented to

  17. Hydrogen generation from deliquescence of ammonia borane using Ni-Co/r-GO catalyst

    Science.gov (United States)

    Chou, Chang-Chen; Chen, Bing-Hung

    2015-10-01

    Hydrogen generation from the catalyzed deliquescence/hydrolysis of ammonia borane (AB) using the Ni-Co catalyst supported on the graphene oxide (Ni-Co/r-GO catalyst) under the conditions of limited water supply was studied with the molar feed ratio of water to ammonia borane (denoted as H2O/AB) at 2.02, 3.97 and 5.93, respectively. The conversion efficiency of ammonia borane to hydrogen was estimated both from the cumulative volume of the hydrogen gas generated and the conversion of boron chemistry in the hydrolysates analyzed by the solid-state 11B NMR. The conversion efficiency of ammonia borane could reach nearly 100% under excess water dosage, that is, H2O/AB = 3.97 and 5.93. Notably, the hydrogen storage capacity could reach as high as 6.5 wt.% in the case with H2O/AB = 2.02. The hydrolysates of ammonia borane in the presence of Ni-Co/r-GO catalyst were mainly the mixture of boric acid and metaborate according to XRD, FT-IR and solid-state 11B NMR analyses.

  18. Polymers containing borane or carborane cage compounds and related applications

    Science.gov (United States)

    Bowen, III, Daniel E; Eastwood, Eric A

    2013-04-23

    Polymers comprising residues of cage compound monomers having at least one polyalkoxy silyl substituent are provided. The cage compound monomers are selected from borane cage compound monomers comprising at least 7 cage atoms and/or carborane cage compound monomers comprising 7 to 11 cage compound monomers. Such polymers can further comprise one or more reactive matrices and/or co-monomers covalently bound with the cage compound monomer residues. Articles of manufacture comprising such polymers are also disclosed.

  19. Characterization of ammonia borane for chemical propulsion applications

    Science.gov (United States)

    Weismiller, Michael

    Ammonia borane (NH3BH3; AB), which has a hydrogen content of 19.6% by weight, has been studied recently as a potential means of hydrogen storage for use in fuel cell applications. Its gaseous decomposition products have a very low molecular weight, which makes AB attractive in a propulsion application, since specific impulse is inversely related to the molecular weight of the products. AB also contains boron, which is a fuel of interest for solid propellants because of its high energy density per unit volume. Although boron particles are difficult to ignite due to their passivation layer, the boron molecularly bound in AB may react more readily. The concept of fuel depots in low-earth orbit has been proposed for use in deep space exploration. These would require propellants that are easily storable for long periods of time. AB is a solid at standard temperature and pressure and would not suffer from mass loss due to boil-off like cryogenic hydrogen. The goal of this work is to evaluate AB as a viable fuel in chemical propulsion. Many studies have examined AB decomposition at slow heating rates, but in a propellant, AB will experience rapid heating. Since heating rate has been shown to affect the thermolysis pathways in energetic materials, AB thermolysis was studied at high heating rates using molecular dynamics simulations with a ReaxFF reactive force field and experimental studies with a confined rapid thermolysis set-up using time-of-flight mass spectrometry and FTIR absorption spectroscopy diagnostics. Experimental results showed the formation of NH3, H2NBH2, H2, and at later times, c-(N3B3H6) in the gas phase, while polymer formation was observed in the condensed phase. Molecular dynamics simulations provided an atomistic description of the reactions which likely form these compounds. Another subject which required investigation was the reaction of AB in oxidizing environments, as there were no previous studies in the literature. Oxygen bond descriptions were

  20. Ruthenium nanoparticles confined in SBA-15 as highly efficient catalyst for hydrolytic dehydrogenation of ammonia borane and hydrazine borane

    Science.gov (United States)

    Yao, Qilu; Lu, Zhang-Hui; Yang, Kangkang; Chen, Xiangshu; Zhu, Meihua

    2015-10-01

    Ultrafine ruthenium nanoparticles (NPs) within the mesopores of the SBA-15 have been successfully prepared by using a “double solvents” method, in which n-hexane is used as a hydrophobic solvent and RuCl3 aqueous solution is used as a hydrophilic solvent. After the impregnation and reduction processes, the samples were characterized by XRD, TEM, EDX, XPS, N2 adsorption-desorption, and ICP techniques. The TEM images show that small sized Ru NPs with an average size of 3.0 ± 0.8 nm are uniformly dispersed in the mesopores of SBA-15. The as-synthesized Ru@SBA-15 nanocomposites (NCs) display exceptional catalytic activity for hydrogen generation by the hydrolysis of ammonia borane (NH3BH3, AB) and hydrazine borane (N2H4BH3, HB) at room temperature with the turnover frequency (TOF) value of 316 and 706 mol H2 (mol Ru min)-1, respectively, relatively high values reported so far for the same reaction. The activation energies (Ea) for the hydrolysis of AB and HB catalyzed by Ru@SBA-15 NCs are measured to be 34.8 ± 2 and 41.3 ± 2 kJ mol-1, respectively. Moreover, Ru@SBA-15 NCs also show satisfied durable stability for the hydrolytic dehydrogenation of AB and HB, respectively.

  1. Dihydrogen Phosphate Stabilized Ruthenium(0 Nanoparticles: Efficient Nanocatalyst for The Hydrolysis of Ammonia-Borane at Room Temperature

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    Feyyaz Durap

    2015-07-01

    Full Text Available Intensive efforts have been devoted to the development of new materials for safe and efficient hydrogen storage. Among them, ammonia-borane appears to be a promising candidate due to its high gravimetric hydrogen storage capacity. Ammonia-borane can release hydrogen on hydrolysis in aqueous solution under mild conditions in the presence of a suitable catalyst. Herein, we report the synthesis of ruthenium(0 nanoparticles stabilized by dihydrogenphosphate anions with an average particle size of 2.9 ± 0.9 nm acting as a water-dispersible nanocatalyst in the hydrolysis of ammonia-borane. They provide an initial turnover frequency (TOF value of 80 min−1 in hydrogen generation from the hydrolysis of ammonia-borane at room temperature. Moreover, the high stability of these ruthenium(0 nanoparticles makes them long-lived and reusable nanocatalysts for the hydrolysis of ammonia-borane. They provide 56,800 total turnovers and retain ~80% of their initial activity even at the fifth catalytic run in the hydrolysis of ammonia-borane at room temperature.

  2. Polymer Film Supported Bimetallic Au-Ag Catalysts for Electrocatalytic Oxidation of Ammonia Borane in Alkaline Media

    Institute of Scientific and Technical Information of China (English)

    Şükriye Ulubay Karabiberoglu; ÇagrCeylan Koçak; Süleyman Kocak; Zekerya Dursun

    2016-01-01

    Ammonia borane is widely used in most areas including fuel cell applications. The present paper describes electrochemical behavior of ammonia borane in alkaline media on the poly(p-aminophenol) film modified with Au and Ag bimetallic nanoparticles. The glassy carbon electrode was firstly covered with polymeric film electrochemically and then, Au, Ag, and Au–Ag nanoparticles were deposited on the polymeric film, respectively. The surface morphology and chemical composition of these electrodes were examined by scanning electron microscopy, transmission electron microscopy, electrochemical impedance spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. It was found that alloyed Au–Ag bimetallic nanoparticles are formed. Electrochemical measurements indicate that the developed electrode modified by Au–Ag bimetallic nanoparticles exhibit the highest electrocatalytic activity for ammonia borane oxidation in alkaline media. The rotating disk electrode voltammetry demonstrates that the developed electrode can catalyze almost six-electron oxidation pathway of ammonia borane. Our results may be attractive for anode materials of ammonia borane fuel cells under alkaline conditions.

  3. The route to a feasible hydrogen-storage material: MOFs versus ammonia borane.

    Science.gov (United States)

    Hügle, Thomas; Hartl, Monika; Lentz, Dieter

    2011-09-05

    The replacement of fossil fuels is one of the greatest challenges that chemistry and material sciences will have to face in the near future. While hydrogen seems to be the most likely candidate for this, a material able to store the hydrogen itself is sorely needed. Intense research in the past decade has narrowed down the field of possible concepts to two materials: ammonia borane with chemically bound hydrogen atoms and metal-organic frameworks with physisorbed hydrogen molecules. Herein we want to give an overview of the strengths and weaknesses of each concept, discuss the challenges that need to be overcome, and try to compare the future capabilities of these two materials.

  4. Materials for hydrogen storage: structure and dynamics of borane ammonia complex.

    Science.gov (United States)

    Parvanov, Vencislav M; Schenter, Gregory K; Hess, Nancy J; Daemen, Luke L; Hartl, Monika; Stowe, Ashley C; Camaioni, Donald M; Autrey, Tom

    2008-09-07

    The activation energies for rotations in low-temperature orthorhombic ammonia borane were analyzed and characterized in terms of electronic structure theory. The perdeuterated (11)B-enriched ammonia borane, (11)BD(3)ND(3), sample was synthesized, and the structure was refined from neutron powder diffraction data at 175 K. This temperature has been chosen as median of the range of previously reported nuclear magnetic resonance spectroscopy measurements of these rotations. A representative molecular cluster model was assembled from the refined geometry, and the activation energies were calculated and characterized by analysis of the environmental factors that control the rotational dynamics. The barrier for independent NH(3) rotation, E(a) = 12.7 kJ mol(-1), largely depends on the molecular conformational torsion in the solid-state geometry. The barrier for independent BH(3) rotation, E(a) = 38.3 kJ mol(-1), results from the summation of the effect of molecular torsion and large repulsive intermolecular hydrogen-hydrogen interactions. However, a barrier of E(a) = 31.1 kJ mol(-1) was calculated for internally correlated rotation with preserved molecular conformation. Analysis of the barrier heights and the corresponding rotational pathways shows that rotation of the BH(3) group involves strongly correlated rotation of the NH(3) end of the molecule. This observation suggests that the barrier from previously reported measurement of BH(3) rotation corresponds to H(3)B-NH(3) correlated rotation.

  5. Influence of Pressure on Physical Property of Ammonia Borane and its Re-hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jiuhua [Florida Intl Univ., Miami, FL (United States)

    2015-08-14

    The project systematically studied the high pressure behavior of ammonia borane and its derivative lithium amidoborane. Phase transitions in these materials are investigated in the pressure range up to 20 GPa and temperature range from 80 K to 400K. A number of new phase transitions are discovered in this pressure and temperature range including a second order transformation at 5 GPa and a first order transformation at 12 GPa at room temperature, and four new transitions at high pressure and low temperatures. The Clapeyron slopes for both pressure-induce tetragonal (I4mm) phase to orthorhombic (Cmc21) phase and temperature-induce tetragonal (I4mm) phase to orthorhombic (Pmn21) phase are determined to be positive, indicating these phase transitions are exothermic. This result demonstrates that the high pressure orthorhombic phase of ammonia borane has lower enthalpy than that of tetragonal phase at ambient conditions. If we assume decomposition from the orthorhombic phase yields the same products as that from the tetragonal phase, the decomposition of the orthorhombic phase will be less exothermic. Therefore rehydrogenation from the decomposed product into the orthorhombic phase at high pressure may become easier. The project also studied the influences of nanoconfinement on the phase transitions. Comparative study using Raman spectroscopy indicates that the temperature induced I4mm to Pmn21 transition is suppressed from 217 K to 195 K when the sample is confined in SBA15 (7-9 nm pore size). When the pore size is reduced from 7-9 nm to 3-4 nm, this transition is totally suppressed in the temperature down to 80 K. A similar influence of the nanoconfiement on pressure induced phase transitions is also observed using Raman spectroscopy. The phase boundary between the I4mm phase and high pressure Cmc21 phase at ambient temperature shifts from 0.9 GPa to 0.5 GPa; and that between the Cmc21 phase and higher pressure P21 phase shifts from 10.2 GPa to 9.7 GPa.

  6. Decomposition Pathway of Ammonia Borane on the Surface of nano-BN

    Energy Technology Data Exchange (ETDEWEB)

    Neiner, Doinita; Luedtke, Avery T; Karkamkar, Abhijeet J; Shaw, Wendy J; Wang, Julia; Browning, Nigel; Autrey, Thomas; Kauzlarich, Susan M

    2010-08-19

    Ammonia borane (AB) is under significant investigation as a possible hydrogen storage material. While many chemical additives have been demonstrated to have a significant positive effect on hydrogen release from ammonia borane, many provide additional complications in the regeneration cycle. Mechanically alloyed hexagonal BN (nano-BN) has been shown to facilitate the release of hydrogen from AB at lower temperature, with minimal induction time, less exothermically, and inert nano-BN may be easily removed during any regeneration of the spent AB. The samples were prepared by mechanically alloying AB with nano-BN. Raman spectroscopy indicates that the AB:nano-BN samples are physical mixtures of AB and h-BN. The release of hydrogen from AB:nano-BN mixtures as well as the decomposition products were characterized by 11B magic angle spinning (MAS) solid state NMR, TGA/DSC/MS with 15N labeled AB, and solution 11B NMR spectroscopy. The 11B MAS solid state NMR spectrum shows that diammonate of diborane (DADB) is present in the mechanically alloyed mixture, which drastically shortens the induction period for hydrogen release from AB. Analysis of the TGA/DSC/MS spectra using 15N labeled AB shows that all the borazine (BZ) produced in the reaction comes from AB and that increasing nano-BN surface area results in increased amounts of BZ. However, under high temperature, 150°C, isothermal conditions, the amount of BZ released was the same as for neat AB. High resolution transmission electron microscopy (HRTEM), selected area diffraction (SAD), and electron energy loss spectroscopy (EELS) of the initial and final nano-BN additive provide evidence for crystallinity loss but not significant chemical changes. The higher concentration of BZ observed for low temperature dehydrogenation of AB:nano-BN mixtures versus neat AB is attributed to a surface interaction that favors the formation of precursors which ultimately result in BZ

  7. One-pot synthesis of core-shell Cu@SiO2 nanospheres and their catalysis for hydrolytic dehydrogenation of ammonia borane and hydrazine borane

    Science.gov (United States)

    Yao, Qilu; Lu, Zhang-Hui; Zhang, Zhujun; Chen, Xiangshu; Lan, Yaqian

    2014-12-01

    Ultrafine copper nanoparticles (Cu NPs) within porous silica nanospheres (Cu@SiO2) were prepared via a simple one-pot synthetic route in a reverse micelle system and characterized by SEM, TEM, EDX, XRD, N2 adsorption-desorption, CO-TPD, XPS, and ICP methods. The characterized results show that ultrafine Cu NPs with diameter of around 2 nm are effectively embedded in the center of well-proportioned spherical SiO2 NPs of about 25 nm in diameter. Compared to commercial SiO2 supported Cu NPs, SiO2 nanospheres supported Cu NPs, and free Cu NPs, the synthesized core-shell nanospheres Cu@SiO2 exhibit a superior catalytic activity for the hydrolytic dehydrogenation of ammonia borane (AB, NH3BH3) and hydrazine borane (HB, N2H4BH3) under ambient atmosphere at room temperature. The turnover frequencies (TOF) for the hydrolysis of AB and HB in the presence of Cu@SiO2 nanospheres were measured to be 3.24 and 7.58 mol H2 (mol Cu min)-1, respectively, relatively high values for Cu nanocatalysts in the same reaction. In addition, the recycle tests show that the Cu@SiO2 nanospheres are still highly active in the hydrolysis of AB and HB, preserving 90 and 85% of their initial catalytic activity even after ten recycles, respectively.

  8. Portable ammonia-borane-based H2 power-pack for unmanned aerial vehicles

    Science.gov (United States)

    Seo, Jung-Eun; Kim, Yujong; Kim, Yongmin; Kim, Kibeom; Lee, Jin Hee; Lee, Dae Hyung; Kim, Yeongcheon; Shin, Seock Jae; Kim, Dong-Min; Kim, Sung-Yug; Kim, Taegyu; Yoon, Chang Won; Nam, Suk Woo

    2014-05-01

    An advanced ammonia borane (AB)-based H2 power-pack is designed to continually drive an unmanned aerial vehicle (UAV) for 57 min using a 200-We polymer electrolyte membrane fuel cell (PEMFC). In a flight test with the UAV platform integrated with the developed power-pack, pure hydrogen with an average flow rate of 3.8 L(H2) min-1 is generated by autothermal H2-release from AB with tetraethylene glycol dimethylether (T4EGDE) as a promoter. During take-off, a hybridized power management system (PMS) consisting of the fuel cell and an auxiliary lithium-ion battery supplies 500 We at full power simultaneously, while the fuel cell alone provides 150-200 We and further recharges the auxiliary battery upon cruising. Gaseous byproducts identified by in situ Fourier transform infrared (FT-IR) spectroscopy during AB dehydrogenation are sequestrated using a mixed absorbent in an H2 purification system. In addition, a real-time monitoring system is employed to determine the remaining filter capacity of the purifier at a ground control system for rapidly responding unpredictable circumstances during flight. Separate experiments are conducted to screen potential materials and methods for enhancing filter capacity in the current H2 refining system. A prospective reactor concept for long-term fuel cell applications is proposed based on the results.

  9. Highly active metastable ruthenium nanoparticles for hydrogen production through the catalytic hydrolysis of ammonia borane.

    Science.gov (United States)

    Abo-Hamed, Enass K; Pennycook, Timothy; Vaynzof, Yana; Toprakcioglu, Chris; Koutsioubas, Alexandros; Scherman, Oren A

    2014-08-13

    Late transition metal nanoparticles (NPs) with a favorably high surface area to volume ratio have garnered much interest for catalytic applications. Yet, these NPs are prone to aggregation in solution, which has been mitigated through attachment of surface ligands, additives or supports; unfortunately, protective ligands can severely reduce the effective surface area on the NPs available for catalyzing chemical transformations. The preparation of 'metastable' NPs can readily address these challenges. We report herein the first synthesis of monodisperse metastable ruthenium nanoparticles (RuNPs), having sub 5 nm size and an fcc structure, in aqueous media at room temperature, which can be stored for a period of at least 8 months. The RuNPs can subsequently be used for the catalytic, quantitative hydrolysis of ammonia-borane (AB) yielding hydrogen gas with 21.8 turnovers per min at 25 °C. The high surface area available for hydrolysis of AB on the metastable RuNPs translated to an Ea of 27.5 kJ mol(-1) , which is notably lower than previously reported values for RuNP based catalysts.

  10. Graphene-supported Ag-based core-shell nanoparticles for hydrogen generation in hydrolysis of ammonia borane and methylamine borane.

    Science.gov (United States)

    Yang, Lan; Luo, Wei; Cheng, Gongzhen

    2013-08-28

    Well-dispersed magnetically recyclable core-shell Ag@M (M = Co, Ni, Fe) nanoparticles (NPs) supported on graphene have been synthesized via a facile in situ one-step procedure, using methylamine borane (MeAB) as a reducing agent under ambient condition. Their catalytic activity toward hydrolysis of ammonia borane (AB) were studied. Although the Ag@Fe/graphene NPs are almost inactive, the as-prepared Ag@Co/graphene NPs are the most reactive catalysts, followed by Ag@Ni/graphene NPs. Compared with AB and NaBH4, the as-synthesized Ag@Co/graphene catalysts which reduced by MeAB exert the highest catalytic activity. Additionally, the Ag@Co NPs supported on graphene exhibit higher catalytic activity than the catalysts with other conventional supports, such as the SiO2, carbon black, and γ-Al2O3. The as-synthesized Ag@Co/graphene NPs exert satisfied catalytic activity, with the turnover frequency (TOF) value of 102.4 (mol H2 min(-1) (mol Ag)(-1)), and the activation energy Ea value of 20.03 kJ/mol. Furthermore, the as-synthesized Ag@Co/graphene NPs show good recyclability and magnetically reusability for the hydrolytic dehydrogenation of AB and MeAB, which make the practical reusing application of the catalysts more convenient. Moreover, this simple synthetic method indicates that MeAB could be used as not only a potential hydrogen storage material but also an efficient reducing agent. It can be easily extended to facile preparation of other graphene supported metal NPs.

  11. PVP-stabilized Ru–Rh nanoparticles as highly efficient catalysts for hydrogen generation from hydrolysis of ammonia borane

    Energy Technology Data Exchange (ETDEWEB)

    Rakap, Murat, E-mail: mrtrakap@gmail.com

    2015-11-15

    Herein, the utilization of poly(N-vinyl-2-pyrrolidone)-protected ruthenium–rhodium nanoparticles (3.4 ± 1.4 nm) as highly efficient catalysts in the hydrolysis of ammonia borane for hydrogen generation is reported. They are prepared by co-reduction of ruthenium and rhodium metal ions in ethanol/water mixture by an alcohol reduction method and characterized by transmission electron microscopy-energy dispersive X-ray spectroscopy, ultraviolet–visible spectroscopy, and X-ray photoelectron spectroscopy. They are durable and highly efficient catalysts for hydrogen generation from the hydrolysis of ammonia borane even at very low concentrations and temperature, providing average turnover frequency of 386 mol H{sub 2} (mol cat){sup −1} min{sup −1} and maximum hydrogen generation rate of 10,680 L H{sub 2} min{sup −1} (mol cat){sup −1}. Poly(N-vinyl-2-pyrrolidone)-protected ruthenium–rhodium nanoparticles also provide activation energy of 47.4 ± 2.1 kJ/mol for the hydrolysis of ammonia borane. - Highlights: • Ru-Rh@PVP NPs provide a TOF of 386 mol H{sub 2} (mol cat){sup −1} min{sup −1} for hydrolysis of AB. • Maximum HG rate is 9680 L H{sub 2} min{sup −1} (mol cat){sup −1} for the hydrolysis of AB. • Activation energy is 47.4 ± 2.1 kJ mol{sup −1} for the hydrolysis of AB.

  12. Catalytic Hydrolysis of Ammonia Borane by Cobalt Nickel Nanoparticles Supported on Reduced Graphene Oxide for Hydrogen Generation

    Directory of Open Access Journals (Sweden)

    Yuwen Yang

    2014-01-01

    Full Text Available Well dispersed magnetically recyclable bimetallic CoNi nanoparticles (NPs supported on the reduced graphene oxide (RGO were synthesized by one-step in situ coreduction of aqueous solution of cobalt(II chloride, nickel (II chloride, and graphite oxide (GO with ammonia borane (AB as the reducing agent under ambient condition. The CoNi/RGO NPs exhibits excellent catalytic activity with a total turnover frequency (TOF value of 19.54 mol H2 mol catalyst−1 min−1 and a low activation energy value of 39.89 kJ mol−1 at room temperature. Additionally, the RGO supported CoNi NPs exhibit much higher catalytic activity than the monometallic and RGO-free CoNi counterparts. Moreover, the as-prepared catalysts exert satisfying durable stability and magnetically recyclability for the hydrolytic dehydrogenation of AB, which make the practical reusing application of the catalysts more convenient. The usage of the low-cost, easy-getting catalyst to realize the production of hydrogen under mild condition gives more confidence for the application of ammonia borane as a hydrogen storage material. Hence, this general method indicates that AB can be used as both a potential hydrogen storage material and an efficient reducing agent, and can be easily extended to facile preparation of other RGO-based metallic systems.

  13. Towards Safer Rocket Fuels: Hypergolic Imidazolylidene-Borane Compounds as Replacements for Hydrazine Derivatives.

    Science.gov (United States)

    Huang, Shi; Qi, Xiujuan; Liu, Tianlin; Wang, Kangcai; Zhang, Wenquan; Li, Jianlin; Zhang, Qinghua

    2016-07-11

    Currently, toxic and volatile hydrazine derivatives are still the main fuel choices for liquid bipropellants, especially in some traditional rocket propulsion systems. Therefore, the search for safer hypergolic fuels as replacements for hydrazine derivatives has been one of the most challenging tasks. In this study, six imidazolylidene-borane compounds with zwitterionic structure have been synthesized and characterized, and their hypergolic reactivity has been studied. As expected, these compounds exhibited fast spontaneous combustion upon contact with white fuming nitric acid (WFNA). Among them, compound 5 showed excellent integrated properties including wide liquid operating range (-70-160 °C), superior loading density (0.99 g cm(-3) ), ultrafast ignition delay times with WFNA (15 ms), and high specific impulse (303.5 s), suggesting promising application potential as safer hypergolic fuels in liquid bipropellant formulations.

  14. Use of an accelerometer and a microphone as gas detectors in the online quantitative detection of hydrogen released from ammonia borane by gas chromatography.

    Science.gov (United States)

    He, Yi-San; Chen, Kuan-Fu; Lin, Chien-Hung; Lin, Min-Tsung; Chen, Chien-Chung; Lin, Cheng-Huang

    2013-03-19

    The use of an accelerometer as a gas detector in gas chromatography (GC) is described for the first time. A milli-whistle was connected to the outlet of the GC capillary. When the eluted and GC carrier gases pass through the capillary and milli-whistle, a sound is produced. After a fast Fourier transform (FFT), the sound wave generated from the milli-whistle is picked up by a microphone and the resulting vibration of the milli-whistle body can be recorded by an accelerometer. The release of hydrogen gas, as the result of thermal energy, from ammonia borane (NH3BH3), which has been suggested as a storage medium for hydrogen, was selected as the model sample. The findings show that the frequencies generated, either by sound or by the vibration from the whistle body, were identical. The concentration levels of the released hydrogen gas can be determined online, based on the frequency changes. Ammonia borane was placed in a brass reservoir, heated continually, and the released hydrogen gas was directly injected into the GC inlet at 0.5 min intervals, using a home-built electromagnetic pulse injector. The concentration of hydrogen for each injection can be calculated immediately. When the ammonia borane was encapsulated within a polycarbonate (PC) microtube array membrane, the temperature required for the release of hydrogen can be decreased, which would make such a material more convenient for use. The findings indicate that 1.0 mg of ammonia borane can produce hydrogen in the range of 1.0-1.25 mL, in the temperature range of 85-115 °C.

  15. High and rapid hydrogen release from thermolysis of ammonia borane near PEM fuel cell operating temperature

    Energy Technology Data Exchange (ETDEWEB)

    Varma, Arvind; Hwang, Hyun Tae; Al-Kukhun, Ahmad

    2016-11-15

    A system for generating and purifying hydrogen. To generate hydrogen, the system includes inlets configured to receive a hydrogen carrier and an inert insulator, a mixing chamber configured to combine the hydrogen carrier and the inert insulator, a heat exchanger configured to apply heat to the mixture of hydrogen carrier and the inert insulator, wherein the applied heat results in the generation of hydrogen from the hydrogen carrier, and an outlet configured to release the generated hydrogen. To purify hydrogen, the system includes a primary inlet to receive a starting material and an ammonia filtration subassembly, which may include an absorption column configured to absorb the ammonia into water for providing purified hydrogen at a first purity level. The ammonia filtration subassembly may also include an adsorbent member configured to adsorb ammonia from the starting material into an adsorbent for providing purified hydrogen at a second purity level.

  16. Studies on the sythesis of c-BN layers with ECWR-PACVD and borane- ammonia as educt material

    CERN Document Server

    Schumacher, A

    2000-01-01

    Boron nitride films were deposited by controlled plasma assisted chemical vapor deposition (PACVD) on the basis of borane-ammonia (BH sub 3 NH sub 3) as B- and N- supplier. Having a high vapor pressure, this white crystalline solid of less toxicity in comparision to generally used boron precursors can easily be transferred into the gas phase by moderate heating. Together with argon as working gas the BH sub 3 NH sub 3 -vapor is led into a two-circuit plasma source utilizing the electron cyclotron wave resonance technique (ECWR) for ionization and dissoziation of the gas mixture by electron impact in the low pressure range (propor to 10 mbar). For a precise adjustment of the energy of the ionic plasma species arriving at the growing film, an r.f.-diode circuit is superimposed to the discharge. Since for a controlled film deposition by PACVD a stationary plasma composition is mandatory, the evaporation characteristics of the reactant source was determined primarily. Therefore the evolution of the plasma and the...

  17. Room temperature hydrogen generation from hydrolysis of ammonia-borane over an efficient NiAgPd/C catalyst

    KAUST Repository

    Hu, Lei

    2014-12-01

    NiAgPd nanoparticles are successfully synthesized by in-situ reduction of Ni, Ag and Pd salts on the surface of carbon. Their catalytic activity was examined in ammonia borane (NH3BH3) hydrolysis to generate hydrogen gas. This nanomaterial exhibits a higher catalytic activity than those of monometallic and bimetallic counterparts and a stoichiometric amount of hydrogen was produced at a high generation rate. Hydrogen production rates were investigated in different concentrations of NH3BH3 solutions, including in the borates saturated solution, showing little influence of the concentrations on the reaction rates. The hydrogen production rate can reach 3.6-3.8 mol H2 molcat -1 min-1 at room temperature (21 °C). The activation energy and TOF value are 38.36 kJ/mol and 93.8 mol H2 molcat -1 min-1, respectively, comparable to those of Pt based catalysts. This nanomaterial catalyst also exhibits excellent chemical stability, and no significant morphology change was observed from TEM after the reaction. Using this catalyst for continuously hydrogen generation, the hydrogen production rate can be kept after generating 6.2 L hydrogen with over 10,000 turnovers and a TOF value of 90.3 mol H2 molcat -1 min-1.

  18. Self-supported Cu(OH)2@Co2CO3(OH)2 core-shell nanowire array as a robust catalyst for ammonia-borane hydrolysis

    Science.gov (United States)

    Wang, Jianmei; Ma, Xiao; Yang, Wenrong; Sun, Xuping; Liu, Jingquan

    2017-01-01

    High hydrogen content and long-term stability in aqueous solutions make ammonia-borane (AB) a promising hydrogen-storage material. It is highly attractive but still challenging to develop efficient catalysts for real-time and controllable hydrogen release from AB solution under mild conditions. Herein, we describe the use of a three-dimensional hierarchical Cu(OH)2@Co2CO3(OH)2 core-shell nanowire array on copper foam (denoted as Cu(OH)2@Co2CO3(OH)2/CF) as a highly efficient catalyst for hydrolytic dehydrogenation of AB. The Cu(OH)2@Co2CO3(OH)2/CF works as an on/off switch for on-demand hydrogen generation with a low activation energy of 44.3 KJ mol-1 and a turnover frequency of 39.72 mol(H2)/mol(cat.)/min. It also maintains activity and integration after long-term usage.

  19. Core-shell structured nanospheres with mesoporous silica shell and Ni core as a stable catalyst for hydrolytic dehydrogenation of ammonia borane

    Institute of Scientific and Technical Information of China (English)

    Hua; Liu; Changyan; Cao; Ping; Li; Yu; Yu; Weiguo; Song

    2014-01-01

    Core-shell structured nanospheres with mesoporous silica shell and Ni core(denoted as Ni@meso-SiO2) are prepared through a three-step process. Monodispersed Ni precursors are first prepared, and then coated with mesoporous SiO2. Final Ni@meso-SiO2spheres are obtained after calcination. The products are characterized by X-ray powder diffraction, transmission electron microscopy and N2adsorption-desorption methods. These spheres have a high surface area and are well dispersed in water, showing a high catalytic activity with a TOF value of 18.5,and outstanding stability in hydrolytic dehydrogenation of ammonia borane at room temperature.

  20. Probing the electronic structure of M-graphene oxide (M = Ni, Co, NiCo) catalysts for hydrolytic dehydrogenation of ammonia borane

    Science.gov (United States)

    Zhao, Binhua; Liu, Jinyin; Zhou, Litao; Long, Dan; Feng, Kun; Sun, Xuhui; Zhong, Jun

    2016-01-01

    Various metal elements (M = Ni, Co, NiCo) were dispersed on graphene oxide (GO) to form the M-GO hybrids by a facile way. The hybrids showed good catalytic activities in the hydrolytic dehydrogenation of ammonia borane (AB, NH3BH3), which were significantly enhanced when compared to the metal nanoparticles or GO alone. The electronic structure of the hybrids has been probed by scanning transmission X-ray microscopy (STXM). The distribution of metal elements was clearly imaged with identical electronic structure. Moreover, an interfacial interaction between metal and GO was observed with the peak intensity proportional to the catalytic performance in the hydrolysis of AB. The results provide new insight into the enhanced performance of the M-GO hybrids and may help for the design of advanced catalysts.

  1. Revealing the synergetic effects in Ni nanoparticle-carbon nanotube hybrids by scanning transmission X-ray microscopy and their application in the hydrolysis of ammonia borane

    Science.gov (United States)

    Zhao, Guanqi; Zhong, Jun; Wang, Jian; Sham, Tsun-Kong; Sun, Xuhui; Lee, Shuit-Tong

    2015-05-01

    The hybrids of carbon nanotubes (CNTs) and the supported Ni nanoparticles (NPs) have been studied by scanning transmission X-ray microscopy (STXM) and tested by the hydrolysis reaction of ammonia borane (AB, NH3BH3). Data clearly showed the existence of a strong interaction between Ni NPs and thin CNTs (C-O-Ni bonds), which favored the tunable (buffer) electronic structure of Ni NPs facilitating the catalytic process. The hydrolysis process of AB confirmed the hypothesis that the hybrids with a strong interfacial interaction would show superior catalytic performance, while the hybrids with a weak interfacial interaction show poor performance. Our results provide a wealth of detailed information regarding the electronic structure of the NP-CNT hybrids and provide guidance towards the rational design of high-performance catalysts for energy applications.The hybrids of carbon nanotubes (CNTs) and the supported Ni nanoparticles (NPs) have been studied by scanning transmission X-ray microscopy (STXM) and tested by the hydrolysis reaction of ammonia borane (AB, NH3BH3). Data clearly showed the existence of a strong interaction between Ni NPs and thin CNTs (C-O-Ni bonds), which favored the tunable (buffer) electronic structure of Ni NPs facilitating the catalytic process. The hydrolysis process of AB confirmed the hypothesis that the hybrids with a strong interfacial interaction would show superior catalytic performance, while the hybrids with a weak interfacial interaction show poor performance. Our results provide a wealth of detailed information regarding the electronic structure of the NP-CNT hybrids and provide guidance towards the rational design of high-performance catalysts for energy applications. Electronic supplementary information (ESI) available: Magnified TEM images, high resolution TEM images and the particle size distributions of the samples, the STXM results of a thick tube at different positions, XPS results, stability test. See DOI: 10.1039/c5nr01168j

  2. The roles of dihydrogen bonds in amine borane chemistry.

    Science.gov (United States)

    Chen, Xuenian; Zhao, Ji-Cheng; Shore, Sheldon G

    2013-11-19

    A dihydrogen bond (DHB) is an electrostatic interaction between a protonic hydrogen and a hydridic hydrogen. Over the past two decades, researchers have made significant progress in the identification and characterization of DHBs and their properties. In comparison with conventional hydrogen bonds (HBs), which have been widely used in catalysis, molecular recognition, crystal engineering, and supramolecular synthesis, chemists have only applied DHBs in very limited ways. Considering that DHBs and conventional HBs have comparable strength, DHBs could be more widely applied in chemistry. Over the past several years, we have explored the impact of DHBs on amine borane chemistry and the syntheses and characterization of amine boranes and ammoniated metal borohydrides for hydrogen storage. Through systematic computational and experimental investigations, we found that DHBs play a dominant role in dictating the reaction pathways (and thus different products) of amine boranes where oppositely charged hydrogens coexist for DHB formation. Through careful experiments, we observed, for the first time, a long-postulated reaction intermediate, ammonia diborane (AaDB), whose behavior is essential to mechanistic understanding of the formation of the diammoniate of diborane (DADB) in the reaction of ammonia (NH3) with tetrahydrofuran borane (THF·BH3). The formation of DADB has puzzled the boron chemistry community for decades. Mechanistic insight enabled us to develop facile syntheses of aminodiborane (ADB), ammonia borane (AB), DADB, and an inorganic butane analog NH3BH2NH2BH3 (DDAB). Our examples, together with those in the literature, reinforce the fact that DHB formation and subsequent molecular hydrogen elimination are a viable approach for creating new covalent bonds and synthesizing new materials. We also review the strong effects of DHBs on the stability of conformers and the hydrogen desorption temperatures of boron-nitrogen compounds. We hope that this Account will

  3. 氨硼烷低温和室温结构的第一性原理计算%First-principles Study of Structure of Ammonia Borane

    Institute of Scientific and Technical Information of China (English)

    刘超仁; 胡青苗; 王平

    2011-01-01

    Two kinds of crystal structures (Pmn21 and P42cm) of (ammonia borane) are studied using first-principles plane wave pseudopotential method based on density functional theory in this paper. It was found that the Pmn21 structure is energetically more stable than the P42cm structure at 0 K.This agrees well with the experimental observation, that lower temperature phase is the Pmn21 structure whereas the room temperature phase is P42cm structure. The structure difference between Pmn21 and P42cm phases manifests itself mainly by the variation of intermolecular bond length whereas the intramolecular bond length remains almost unchanged. Electronic state of density was calculated to identify the bonding nature of ammonia borane. The XRD and FTIR patterns of the P42cm structure were calculated, results agree well with the experimental results of AB at room temperature.%采用第-性原理平面波赝暖势方法研究了两种氨硼烷结构(Pmn21及P42cm)的晶格参数、电子结构以及动力学性质.结果表明,Pmn21结构的能量低于P42cm结构,与实验观测结果相符,即低温相为Pmn21结构而室温相为P42cm结构.Pmn21到P42cm相变所引起的结构变化主要体现为氨硼烷分子间双氢键键长显著增加,而分子内部化学键键长变化不大.根据电子态密度分析了氨硼烷的成键状态.氨硼烷室温相的XRD图谱和FTIR图谱的理论预测结果与实验结果符合得较好.

  4. Aqueous solution synthesis of Pt-M (M = Fe, Co, Ni) bimetallic nanoparticles and their catalysis for the hydrolytic dehydrogenation of ammonia borane.

    Science.gov (United States)

    Wang, Shuai; Zhang, Duo; Ma, Yanyun; Zhang, Hui; Gao, Jing; Nie, Yuting; Sun, Xuhui

    2014-08-13

    Platinum-based bimetallic nanocatalysts have attracted much attention due to their high-efficiency catalytic performance in energy-related applications such as fuel cell and hydrogen storage, for example, the hydrolytic dehydrogenation of ammonia borane (AB). In this work, a simple and green method has been demonstrated to successfully prepare Pt-M (M = Fe, Co, Ni) NPs with tunable composition (nominal Pt/M atomic ratios of 4:1, 1:1, and 1:4) in aqueous solution under mild conditions. All Pt-M NPs with a small size of 3-5 nm show a Pt fcc structure, suggesting the bimetallic formation (alloy and/or partial core-shell), examined by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray absorption fine structure (XAFS) analysis. The catalytic activities of Pt-M NPs in the hydrolytic dehydrogenation of AB reveal that Pt-Ni NPs with a ratio of 4:1 show the best catalytic activity and even better than that of pure Pt NPs when normalized to Pt molar amount. The Ni oxidation state in Pt-Ni NPs has been suggested to be responsible for the corresponding catalytic activity for hydrolytic dehydrogenation of AB by XAFS study. This strategy for the synthesis of Pt-M NPs is simple and environmentally benign in aqueous solution with the potential for scale-up preparation and the in situ catalytic reaction.

  5. Iron complex-catalyzed ammonia-borane dehydrogenation. A potential route toward B-N-containing polymer motifs using earth-abundant metal catalysts.

    Science.gov (United States)

    Baker, R Tom; Gordon, John C; Hamilton, Charles W; Henson, Neil J; Lin, Po-Heng; Maguire, Steven; Murugesu, Muralee; Scott, Brian L; Smythe, Nathan C

    2012-03-28

    Ammonia-borane (NH(3)BH(3), AB) has garnered interest as a hydrogen storage material due to its high weight percent hydrogen content and ease of H(2) release relative to metal hydrides. As a consequence of dehydrogenation, B-N-containing oligomeric/polymeric materials are formed. The ability to control this process and dictate the identity of the generated polymer opens up the possibility of the targeted synthesis of new materials. While precious metals have been used in this regard, the ability to construct such materials using earth-abundant metals such as Fe presents a more economical approach. Four Fe complexes containing amido and phosphine supporting ligands were synthesized, and their reactivity with AB was examined. Three-coordinate Fe(PCy(3))[N(SiMe(3))(2)](2) (1) and four-coordinate Fe(DEPE)[N(SiMe(3))(2)](2) (2) yield a mixture of (NH(2)BH(2))(n) and (NHBH)(n) products with up to 1.7 equiv of H(2) released per AB but cannot be recycled (DEPE = 1,2-bis(diethylphosphino)ethane). In contrast, Fe supported by a bidentate P-N ligand (4) can be used in a second cycle to afford a similar product mixture. Intriguingly, the symmetric analogue of 4 (Fe(N-N)(P-P), 3), only generates (NH(2)BH(2))(n) and does so in minutes at room temperature. This marked difference in reactivity may be the result of the chemistry of Fe(II) vs Fe(0).

  6. Synthesis of hydrides by interaction of intermetallic compounds with ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Tarasov, Boris P., E-mail: tarasov@icp.ac.ru [Institute of Problems of Chemical Physics of the Russian Academy of Sciences, Chernogolovka 142432 (Russian Federation); Fokin, Valentin N.; Fokina, Evelina E. [Institute of Problems of Chemical Physics of the Russian Academy of Sciences, Chernogolovka 142432 (Russian Federation); Yartys, Volodymyr A., E-mail: volodymyr.yartys@ife.no [Institute for Energy Technology, Kjeller NO 2027 (Norway); Department of Materials Science and Engineering, Norwegian University of Science and Technology, Trondheim NO 7491 (Norway)

    2015-10-05

    Highlights: • Interaction of the intermetallics A{sub 2}B, AB, AB{sub 2}, AB{sub 5} and A{sub 2}B{sub 17} with NH{sub 3} was studied. • The mechanism of interaction of the alloys with ammonia is temperature-dependent. • Hydrides, hydridonitrides, disproportionation products or metal–N–H compounds are formed. • NH{sub 4}Cl was used as an activator of the reaction between ammonia and intermetallics. • Interaction with ammonia results in the synthesis of the nanopowders. - Abstract: Interaction of intermetallic compounds with ammonia was studied as a processing route to synthesize hydrides and hydridonitrides of intermetallic compounds having various stoichiometries and types of crystal structures, including A{sub 2}B, AB, AB{sub 2}, AB{sub 5} and A{sub 2}B{sub 17} (A = Mg, Ti, Zr, Sc, Nd, Sm; B = transition metals, including Fe, Co, Ni, Ti and nontransition elements, Al and B). In presence of NH{sub 4}Cl used as an activator of the reaction between ammonia and intermetallic alloys, their interaction proceeds at rather mild P–T conditions, at temperatures 100–200 °C and at pressures of 0.6–0.8 MPa. The mechanism of interaction of the alloys with ammonia appears to be temperature-dependent and, following a rise of the interaction temperature, it leads to the formation of interstitial hydrides; interstitial hydridonitrides; disproportionation products (binary hydride; new intermetallic hydrides and binary nitrides) or new metal–nitrogen–hydrogen compounds like magnesium amide Mg(NH{sub 2}){sub 2}. The interaction results in the synthesis of the nanopowders where hydrogen and nitrogen atoms become incorporated into the crystal lattices of the intermetallic alloys. The nitrogenated materials have the smallest particle size, down to 40 nm, and a specific surface area close to 20 m{sup 2}/g.

  7. 氨基络合物制备氨硼烷及放氢性能研究%Preparation of Ammonia Borane with Ammonia Complex and the Study of Hydrogen Desorption Performance

    Institute of Scientific and Technical Information of China (English)

    邹少爽; 陶占良; 陈军

    2011-01-01

    This paper reports on the synthesis of ammonia borane(NH3BH3,AB) from sodium borohydride and ammonia complex Ni(NH3)6?Cl2 and the dehydrogenation of the as-synthesized AB.The composition and purity of the products have been tested by instrumental analyses of XRD,FTIR,11B NMR and ICP.The effects of raw materials molar ratio,reaction temperature,reaction time and solvent on the synthesis of AB have been systematically investigated.At the same time,a thermal decomposition process has also been ex-plored on the as-prepared AB with different raw material ratios.The results show that a pure phase AB(pu-rity99%) can be obtained with the molar ratio of NaBH4∶Ni(NH3)6Cl2=2∶1 and the reaction time of 10 h.Thermal analysis displays that the hydrogen gas is released in the first step from AB with raw material molar ratio of NaBH4∶Ni(NH3)6Cl2=3∶1,and impurities of diborane(m/e=27),borazine(m/e=80) are effectively inhibited at the heating rate of 2 ℃/min.In addition,a certain amount of Ni nanoparticles with the size of about 10 nm exist in the products,which would be used as a catalyst for the hydrolysis of AB.%以NaBH4为硼源、氨基络合物Ni(NH3)6Cl2为氨源制备高储氢容量的氨硼烷(NH3BH3,Ammonia Borane,AB)及其放氢性能研究.通过XRD,FTIR,11B NMR,ICP等手段分析表征了所制备产物的组成和纯度,在此基础上探究了原料比例、反应温度、时间和溶剂等因素对产物的影响.同时,对不同原料比制得氨硼烷的热解放氢性能进行了研究.实验结果表明:当物质的量NaBH4∶Ni(NH3)6Cl2=2∶1经过10 h的反应,得到了纯度非常高的氨硼烷(纯度〉99%);以NaBH4∶Ni(NH3)6Cl2=3∶1得到的氨硼烷,当以2℃/min进行升温时,氢气释放主要集中在第一步,并且没有硼烷和硼嗪等杂质气体的产生.另外,在产物中得到了金属Ni纳米颗粒,经洗涤干燥后其粒径大小可控制在10 nm左右,在催化氨硼烷等

  8. Staging properties of potassium-ammonia ternary graphite intercalation compounds at high ammonia pressure

    Science.gov (United States)

    Qian, X. W.; Solin, S. A.

    1989-04-01

    The pressure dependence of the (00l) x-ray diffraction patterns of the ternary graphite intercalation compound K(NH3)xC24 has been studied in the range 0.5-11 kbar (for which x~4.5) using a diamond anvil cell. A special apparatus for loading the cell with liquid ammonia at room temperature has been constructed and is briefly described. In these experiments, the pressure-transmitting fluid was also an intercalant, namely ammonia. Therefore, the chemical potential of this species was linearly coupled to the applied pressure in contrast to the usual case where the pressure-transmitting fluid is chemically passive. The pressure dependences of the basal spacings and of the relative intensities of key reflections have been measured, as have the compressibilities of the stage-1 and stage-2 components of the two-phase system. Basal-spacing anomalies and anomalies in the relative intensities occur at pressures of ~3.5 and 8.0 kbar and are tentatively attributed to in-plane coordination changes in the potassium-ammonia ratio. Using thermodynamic arguments and Le Chatelier's principle we show quantitatively that a staging phase transition from pure stage-1 phase to an admixture of stage-1 and stage-2 is expected with increased pressure above 10 bar in agreement with experiment. The saturation ammonia compositions (x values) of the admixed stages are found to be 4.5 and 5.4 for the stage-1 and -2 components, respectively. This result is interpreted as evidence that the composition is not sterically limited but is determined by the binding energy of ammonia for potassium and by the perturbation to this energy from the guest-host interaction.

  9. Nanostructured Polypyrrole-Based Ammonia and Volatile Organic Compound Sensors

    Directory of Open Access Journals (Sweden)

    Milena Šetka

    2017-03-01

    Full Text Available The aim of this review is to summarize the recent progress in the fabrication of efficient nanostructured polymer-based sensors with special focus on polypyrrole. The correlation between physico-chemical parameters, mainly morphology of various polypyrrole nanostructures, and their sensitivity towards selected gas and volatile organic compounds (VOC is provided. The different approaches of polypyrrole modification with other functional materials are also discussed. With respect to possible sensors application in medicine, namely in the diagnosis of diseases via the detection of volatile biomarkers from human breath, the sensor interaction with humidity is described as well. The major attention is paid to analytes such as ammonia and various alcohols.

  10. Reduction of Nitroarenes into Aryl Amines and N-Aryl hydroxylamines via Activation of NaBH4 and Ammonia-Borane Complexes by Ag/TiO2 Catalyst

    Directory of Open Access Journals (Sweden)

    Dimitrios Andreou

    2016-03-01

    Full Text Available In this study, we report the fabrication of mesoporous assemblies of silver and TiO2 nanoparticles (Ag/MTA and demonstrate their catalytic efficiency for the selective reduction of nitroarenes. The Ag/TiO2 assemblies, which show large surface areas (119–128 m2·g−1 and narrow-sized mesopores (ca. 7.1–7.4 nm, perform as highly active catalysts for the reduction of nitroarenes, giving the corresponding aryl amines and N-aryl hydroxylamines with NaBH4 and ammonia-borane (NH3BH3, respectively, in moderate to high yields, even in large scale reactions (up to 5 mmol. Kinetic studies indicate that nitroarenes substituted with electron-withdrawing groups reduced faster than those with electron-donating groups. The measured positive ρ values from the formal Hammett-type kinetic analysis of X-substituted nitroarenes are consistent with the proposed mechanism that include the formation of possible [Ag]-H hybrid species, which are responsible for the reduction process. Because of the high observed chemo selectivities and the clean reaction processes, the present catalytic systems, i.e., Ag/MTA-NaBH4 and Ag/MTA-NH3BH3, show promise for the efficient synthesis of aryl amines and N-aryl hydroxylamines at industrial levels.

  11. Numerical Sequence of Borane Series

    Directory of Open Access Journals (Sweden)

    Enos Masheija Kiremire

    2014-09-01

    Full Text Available A table of hydroborane families has been created. The table links boranes of different families(homologous series and members of the same family based on k number. The table is useful deducing straight away whether a borane( molecular formula is closo, nido or arachno or something else. The table also indicates that boranes are formed according to natural periodic function (arithmetical progression. The empirical formula utilized is extremely versatile, simple and based on the principle of Nobel gas configuration. It could be used in both simple and complex boranes and carboranes. The closo members which portray characteristic shapes also have characteristic k1 numbers.

  12. [Ammonia volatilization of slow release compound fertilizer in different soils water conditions].

    Science.gov (United States)

    Hu, Xiao-feng; Wang, Zheng-yin; You, Yuan; Li, Jing-chao

    2010-08-01

    By using venting method incubation experiment, we studied the ammonia volatilization and kinetics characteristics of uncoated slowed release compound fertilizer (SRF) under different soil water conditions and the growth and nitrogen utilization efficiency of rice in pot experiment. Results indicated that the ammonia volatilization of SRF under waterflooding reached the peak ahead of 3-4 days compared to the moist treatment. The peak and accumulation of ammonia volatilization in the waterflooding treatments were higher than those under the moist condition. SRF could significantly reduce total ammonia volatilization compared to the common compound fertilizer (CCF), reduced by 50.6% and 22.8% in the moist treatment and reduced by 24.2% and 10.4% in the waterflooding treatment,but the loss of ammonia volatilization of SRF was higher significantly than that of the coated fertilizer (CRF). Ammonia volatilization increased with the increasing of fertilizer application. The dynamics of ammonia volatilization of SRF could be quantitatively described with three equations: the first order kinetics equation, Elovich equation and parabola equation. Compared to moist condition, the biomass of rice plant in SRF, CCF and SRF treatments increased by 67.86%, 78.25% and 48.75%, and nitrogen utilization efficiency increased by 57.73%, 80.70% and 12.06% under waterflooding condition, respectively. Comparing with CCF, nitrogen utilization efficiency in SRF treatment improved by 59.10% and 10.40% under two soil moisture conditions. SRF could reduce ammonia volatilization and improve biomass and nitrogen utilization efficiency.

  13. In situ Synchrotron X-ray Thermodiffraction of Boranes

    Directory of Open Access Journals (Sweden)

    Pascal G. Yot

    2016-01-01

    Full Text Available Boranes of low molecular weight are crystalline materials that have been much investigated over the past decade in the field of chemical hydrogen storage. In the present work, six of them have been selected to be studied by in situ synchrotron X-ray thermodiffraction. The selected boranes are ammonia borane NH3BH3 (AB, hydrazine borane N2H4BH3 (HB, hydrazine bisborane N2H4(BH32 (HBB, lithium LiN2H3BH3 (LiHB and sodium NaN2H3BH3 (NaHB hydrazinidoboranes, and sodium triborane NaB3H8 (STB. They are first investigated separately over a wide range of temperature (80–300 K, and subsequently compared. Differences in crystal structures, the existence of phase transition, evolutions of unit cell parameters and volumes, and variation of coefficients of thermal expansion can be observed. With respect to AB, HB and HBB, the differences are mainly explained in terms of molecule size, conformation and motion (degree of freedom of the chemical groups (NH3, N2H4, BH3. With respect to LiHB, NaHB and STB, the differences are explained by a stabilization effect favored by the alkali cations via M···H interactions with four to five borane anions. The main results are presented and discussed herein.

  14. Ammonia as a case study for the spontaneous ionization of a simple hydrogen-bonded compound.

    Science.gov (United States)

    Palasyuk, Taras; Troyan, Ivan; Eremets, Mikhail; Drozd, Vadym; Medvedev, Sergey; Zaleski-Ejgierd, Patryk; Magos-Palasyuk, Ewelina; Wang, Hongbo; Bonev, Stanimir A; Dudenko, Dmytro; Naumov, Pavel

    2014-03-24

    Modern ab initio calculations predict ionic and superionic states in highly compressed water and ammonia. The prediction apparently contradicts state-of-the-art experimentally established phase diagrams overwhelmingly dominated by molecular phases. Here we present experimental evidence that the threshold pressure of ~120 GPa induces in molecular ammonia the process of autoionization to yet experimentally unknown ionic compound--ammonium amide. Our supplementary theoretical simulations provide valuable insight into the mechanism of autoionization showing no hydrogen bond symmetrization along the transformation path, a remarkably small energy barrier between competing phases and the impact of structural rearrangement contribution on the overall conversion rate. This discovery is bridging theory and experiment thus opening new possibilities for studying molecular interactions in hydrogen-bonded systems. Experimental knowledge on this novel ionic phase of ammonia also provides strong motivation for reconsideration of the theory of molecular ice layers formation and dynamics in giant gas planets.

  15. Quantum Monte Carlo calculations of the dimerization energy of borane.

    Science.gov (United States)

    Fracchia, Francesco; Bressanini, Dario; Morosi, Gabriele

    2011-09-07

    Accurate thermodynamic data are required to improve the performance of chemical hydrides that are potential hydrogen storage materials. Boron compounds are among the most interesting candidates. However, different experimental measurements of the borane dimerization energy resulted in a rather wide range (-34.3 to -39.1) ± 2 kcal/mol. Diffusion Monte Carlo (DMC) simulations usually recover more than 95% of the correlation energy, so energy differences rely less on error cancellation than other methods. DMC energies of BH(3), B(2)H(6), BH(3)CO, CO, and BH(2)(+) allowed us to predict the borane dimerization energy, both via the direct process and indirect processes such as the dissociation of BH(3)CO. Our D(e) = -43.12(8) kcal/mol, corrected for the zero point energy evaluated by considering the anharmonic contributions, results in a borane dimerization energy of -36.59(8) kcal/mol. The process via the dissociation of BH(3)CO gives -34.5(2) kcal/mol. Overall, our values suggest a slightly less D(e) than the most recent W4 estimate D(e) = -44.47 kcal/mol [A. Karton and J. M. L. Martin, J. Phys. Chem. A 111, 5936 (2007)]. Our results show that reliable thermochemical data for boranes can be predicted by fixed node (FN)-DMC calculations.

  16. Final Report for the DOE-BES Program Mechanistic Studies of Activated Hydrogen Release from Amine-Boranes

    Energy Technology Data Exchange (ETDEWEB)

    Larry G. Sneddon; R. Thomas Baker

    2013-01-13

    Effective storage of hydrogen presents one of the most significant technical gaps to successful implementation of the hydrogen economy, particularly for transportation applications. Amine boranes, such as ammonia borane H3NBH3 and ammonia triborane H3NB3H7, have been identified as promising, high-capacity chemical hydrogen storage media containing potentially readily released protic (N-H) and hydridic (B-H) hydrogens. At the outset of our studies, dehydrogenation of ammonia borane had been studied primarily in the solid state, but our DOE sponsored work clearly demonstrated that ionic liquids, base-initiators and/or metal-catalysts can each significantly increase both the rate and extent of hydrogen release from amine boranes under moderate conditions. Our studies also showed that depending upon the activation method, hydrogen release from amine boranes can occur by very different mechanistic steps and yield different types of spent-fuel materials. The fundamental understanding that was developed during this grant of the pathways and controlling factors for each of these hydrogen-release mechanisms is now enabling continuing discovery and optimization of new chemical-hydride based hydrogen storage systems.

  17. Metal and alloy nanoparticles by amine-borane reduction of metal salts by solid-phase synthesis: atom economy and green process.

    Science.gov (United States)

    Sanyal, Udishnu; Jagirdar, Balaji R

    2012-12-03

    A new solid state synthetic route has been developed toward metal and bimetallic alloy nanoparticles from metal salts employing amine-boranes as the reducing agent. During the reduction, amine-borane plays a dual role: acts as a reducing agent and reduces the metal salts to their elemental form and simultaneously generates a stabilizing agent in situ which controls the growth of the particles and stabilizes them in the nanosize regime. Employing different amine-boranes with differing reducing ability (ammonia borane (AB), dimethylamine borane (DMAB), and triethylamine borane (TMAB)) was found to have a profound effect on the particle size and the size distribution. Usage of AB as the reducing agent provided the smallest possible size with best size distribution. Employment of TMAB also afforded similar results; however, when DMAB was used as the reducing agent it resulted in larger sized nanoparticles that are polydisperse too. In the AB mediated reduction, BNH(x) polymer generated in situ acts as a capping agent whereas, the complexing amine of the other amine-boranes (DMAB and TMAB) play the same role. Employing the solid state route described herein, monometallic Au, Ag, Cu, Pd, and Ir and bimetallic CuAg and CuAu alloy nanoparticles of <10 nm were successfully prepared. Nucleation and growth processes that control the size and the size distribution of the resulting nanoparticles have been elucidated in these systems.

  18. Effectiveness of porous covers for control of ammonia, reduced sulfur compounds, total hydrocarbons, selected volatile organic compounds, and odor from hog manure storage lagoons.

    Science.gov (United States)

    Regmi, Shekhar; Ongwandee, Maneerat; Morrison, Glenn; Fitch, Mark; Surampalli, Rao

    2007-06-01

    Anaerobic lagoons are a major source of odor at concentrated animal feeding operations. Seven different kinds of artificial (geotextile and polyethylene foam) and natural (straw and redwood) permeable lagoon covers were evaluated for their potential to reduce odorous emissions generated by anaerobic waste lagoons. A novel floating sampling raft was constructed and used to simultaneously evaluate the effectiveness of lagoon covers on an operating swine waste lagoon. The air collected from the raft was evaluated for odor, total reduced sulfur (TRS) compounds, ammonia, total hydrocarbons, dimethyldisulfide, and trimethylamine. The emission rates from the lagoon were highly variable both temporally and spatially. All of the lagoon covers substantially reduced TRS emissions and odor. Geotextile fabric and a recycled foam cover exhibited the greatest reduction in total hydrocarbon emissions; natural covers were less effective. Because of consistently low emission rates of ammonia, no statistically significant reduction of ammonia emissions were observed from any of the lagoon covers.

  19. Soluble phenolic compounds in different cultivars of red clover and alfalfa, and their implication for protection against proteolysis and ammonia production in ruminants

    Science.gov (United States)

    Red clover contains phenolic compounds with roles in inhibiting proteolysis and loss of amino acids as ammonia. Alfalfa has been found to have lower concentrations of phenolic compounds, but few alfalfa and red clover cultivars have been compared for phenolic content. Total soluble phenolic compou...

  20. Catalytic dehydrogenation of amine borane complexes

    Science.gov (United States)

    Mohajeri, Nahid (Inventor); Tabatabaie-Raissi, Ali (Inventor); Bokerman, Gary (Inventor)

    2009-01-01

    A method of generating hydrogen includes the steps of providing an amine borane (AB) complex, at least one hydrogen generation catalyst, and a solvent, and mixing these components Hydrogen is generated. The hydrogen produced is high purity hydrogen suitable for PEM fuel cells. A hydrolytic in-situ hydrogen generator includes a first compartment that contains an amine borane (AB) complex, a second container including at least one hydrogen generation catalyst, wherein the first or second compartment includes water or other hydroxyl group containing solvent. A connecting network permits mixing contents in the first compartment with contents in the second compartment, wherein high purity hydrogen is generated upon mixing. At least one flow controller is provided for controlling a flow rate of the catalyst or AB complex.

  1. Tris(pentafluorophenyl)borane-Catalyzed Acceptorless Dehydrogenation of N-Heterocycles.

    Science.gov (United States)

    Kojima, Masahiro; Kanai, Motomu

    2016-09-26

    Catalytic acceptorless dehydrogenation is an environmentally benign way to desaturate organic compounds. This process is traditionally accomplished with transition-metal-based catalysts. Herein, a borane-catalyzed, metal-free acceptorless dehydrogenation of saturated N-heterocycles is disclosed. Tris(pentafluorophenyl)borane was identified as a versatile catalyst, which afforded several synthetically important N-heteroarenes in up to quantitative yield. Specifically, the present metal-free catalytic system exhibited a uniquely high tolerance toward sulfur functionalities, and demonstrated superior reactivity in the synthesis of benzothiazoles compared to conventional metal-catalyzed systems. This protocol can thus be regarded as the first example of metal-free acceptorless dehydrogenation in synthetic organic chemistry.

  2. Standardization of flux chamber and wind tunnel flux measurements for quantifying volatile organic compound and ammonia emissions from area sources at animal feeding operations

    Science.gov (United States)

    A variety of wind tunnels and flux chambers have been used to measure fluxes of volatile organic compounds (VOC) and ammonia (NH3) at animal feeding operations (AFO). However, there has been little regard to the extreme variation and potential inaccuracies caused by inappropriate air velocity or sw...

  3. A study on multifunction heat pipe type high efficient adsorption refrigerator using compound adsorbent-ammonia

    Institute of Scientific and Technical Information of China (English)

    LU Zisheng; WANG Ruzhu; WANG Liwei; CHEN Chuanjuan

    2006-01-01

    A multifunction heat pipe adsorption refrigerator is designed, which uses solidified compound adsorbent of CaCl2 and activated carbon as adsorbent. Two work conditions, ice-maker driven by the exhaust heat from diesel engine and air-condi- tioning powered by solar energy, are studied. SCP (specific cooling power) and COP (coefficient of per- formance) for different conditions are analyzed. The optimum average SCP and COP for the refrigerator powered by waste heat of diesel engine are 770.4 W/kg and 0.39 at about -20℃ evaporating tem- perature. The optimum average SCP and COP for the refrigerator powered by solar energy are 524.2 W/kg and 0.27 at about 5.6℃ evaporating tempera- ture.

  4. The structure study of boron carbonitride films obtained by use of trimethylamine borane complex

    CERN Document Server

    Kosinova, M L; Fainer, N I; Maximovski, E A; Kuznetsov, F A

    2001-01-01

    Diffraction of synchrotron radiation (SR) was used to investigate crystalline structure and phase composition of thin films (1500-5000 A) of boron carbonitride. These films were synthesized by plasma-enhanced chemical vapor deposition using nontraditional volatile single source precursor trimethylamine borane complex (CH sub 3) sub 3 N centre dot BH sub 3 and its mixture with ammonia. The effect of the gas ratio and substrate temperature on chemical and phase composition as well as the structure of the films were investigated. The XRD peculiarities of texture films and ways of increasing sensibility of measurements were considered. A possibility of the information density rise of the thin film XRD was shown due to application of different methods for recording diffraction patterns.

  5. Hydrazine Borane and Hydrazinidoboranes as Chemical Hydrogen Storage Materials

    Directory of Open Access Journals (Sweden)

    Romain Moury

    2015-04-01

    Full Text Available Hydrazine borane N2H4BH3 and alkali derivatives (i.e., lithium, sodium and potassium hydrazinidoboranes MN2H3BH3 with M = Li, Na and K have been considered as potential chemical hydrogen storage materials. They belong to the family of boron- and nitrogen-based materials and the present article aims at providing a timely review while focusing on fundamentals so that their effective potential in the field could be appreciated. It stands out that, on the one hand, hydrazine borane, in aqueous solution, would be suitable for full dehydrogenation in hydrolytic conditions; the most attractive feature is the possibility to dehydrogenate, in addition to the BH3 group, the N2H4 moiety in the presence of an active and selective metal-based catalyst but for which further improvements are still necessary. However, the thermolytic dehydrogenation of hydrazine borane should be avoided because of the evolution of significant amounts of hydrazine and the formation of a shock-sensitive solid residue upon heating at >300 °C. On the other hand, the alkali hydrazinidoboranes, obtained by reaction of hydrazine borane with alkali hydrides, would be more suitable to thermolytic dehydrogenation, with improved properties in comparison to the parent borane. All of these aspects are surveyed herein and put into perspective.

  6. The nature of the potassium compound acting as a promoter in iron-alumina catalysts for ammonia synthesis

    NARCIS (Netherlands)

    Ommen, van J.G.; Bolink, W.J.; Prasad, J.; Mars, P.

    1975-01-01

    The chemical form of the potassium promoter on an iron-alumina catalyst during ammonia synthesis has been studied by two methods, viz, (i) the measurement of the equilibrium constant of the process KNH2 + H2 KH + NH3, and (ii) chemical analysis of the used catalyst. The equilibrium constant measurem

  7. Borane-catalyzed cracking of C-C bonds in coal; Boran-katalysierte C-C-Bindungungsspaltung in Steinkohle

    Energy Technology Data Exchange (ETDEWEB)

    Narangerel, J.; Haenel, M.W. [Max-Planck-Institut fuer Kohlenforschung, Muelheim an der Ruhr (Germany)

    1998-09-01

    Coal, especially coking coal, was reacted with hydrogen at comparatively mild reaction conditions (150-280 degrees centigrade, 20 MPa hydrogen pressure) in the presence of catalysts consisting of borange reagents and certain transition metal halides to obtaine more than 80 percent of pyridine-soluble products. The influence of the degree of coalification, catalyst and temperature on the borane-catalyzed hydrogenolysis of C-C bonds in coal was investigated. (orig.) [Deutsch] Steinkohlen, insbesondere im Inkohlungsbereich der Fettkohlen (Kokskohlen), werden in Gegenwart von Katalysatoren aus Boran-Reagentien und bestimmten Uebergangsmetallhalogeniden mit Wasserstoff bei vergleichsweise milden Reaktionsbedingungen (250-280 C, 20 MPa Wasserstoffdruck) in zu ueber 80% pyridinloesliche Produkte umgewandelt. Der Einfluss von Inkohlungsgrad, Katalysator und Temperatur auf die Boran-katalysierte C-C-Bindungshydrogenolyse in Kohle wurde untersucht. (orig.)

  8. Tris(pentafluorophenyl)borane and Beyond: Modern Advances in Borylation Chemistry.

    Science.gov (United States)

    Lawson, James R; Melen, Rebecca L

    2017-02-03

    As main-group chemistry, in particular boron chemistry, has expanded and developed over the past 20 years, one reagent has risen to prominence as well. Tris(pentafluorophenyl)borane, B(C6F5)3 (commonly known as BCF), has demonstrated extensive applications in a wide variety of reactions, including borylation, hydrogenation, hydrosilylation, frustrated Lewis pair (FLP) chemistry, Lewis acid catalysis, and more. The high Lewis acidity of B(C6F5)3 is derived from the electronic effects of its three C6F5 rings, rendering it a versatile reagent for a great number of reactions. In addition, the steric bulk of these rings also allows it to function as the Lewis acid in a FLP, granting this reagent yet another synthetically useful application. However, as main-group chemistry continues to evolve as a field, new reagents are required that go beyond BCF, increasing not only the range of reactions available but also the breadth of compounds attainable. Great strides have already been made in order to accomplish this task, and this review will highlight modern advances in boron chemistry relating to borylation reactions. Herein, we will show the recent uses of B(C6F5)3 in borylation reactions while also focusing on current advances in novel borane and borocation usage that eclipses that of the stalwart B(C6F5)3.

  9. Borane-substituted imidazol-2-ylidenes: syntheses in vacuo.

    Science.gov (United States)

    Taylor, Alasdair W; Lovelock, Kevin R J; Jones, Robert G; Licence, Peter

    2011-02-21

    The serendipitous discovery of an efficient reactive distillation is reported. Two borane-substituted imidazol-2-ylidenes have been prepared in high yield from precursor tetrafluoroborate derived room temperature ionic liquids by reactive distillation at T > 500 K and p < 1 × 10(-4) mbar.

  10. Catalytic amine-borane dehydrogenation by a PCP-pincer palladium complex: a combined experimental and DFT analysis of the reaction mechanism.

    Science.gov (United States)

    Rossin, Andrea; Bottari, Giovanni; Lozano-Vila, Ana M; Paneque, Margarita; Peruzzini, Maurizio; Rossi, Andrea; Zanobini, Fabrizio

    2013-03-14

    Catalytic dehydrogenation of ammonia-borane (NH(3)·BH(3), AB) and dimethylamine borane (NHMe(2)·BH(3), DMAB) by the Pd(II) complex [((tBu)PCP)Pd(H(2)O)]PF(6) [(tBu)PCP = 2,6-C(6)H(3)(CH(2)P(t)Bu(2))(2)] leads to oligomerization and formation of spent fuels of general formula cyclo-[BH(2)-NR(2)](n) (n = 2,3; R = H, Me) as reaction byproducts, while one equivalent of H(2) is released per amine-borane equivalent. The processes were followed through multinuclear ((31)P, (1)H, (11)B) variable temperature NMR spectroscopy; kinetic measurements on the hydrogen production rate and the relative rate constants were also carried out. One non-hydridic intermediate could be detected at low temperature, whose chemical nature was explored through a DFT modeling of the reaction mechanism, at the M06//6-31+G(d,p) computational level. The computational output was of help to propose a reliable mechanistic picture of the process.

  11. Borane catalysed ring opening and closing cascades of furans leading to silicon functionalized synthetic intermediates

    Science.gov (United States)

    Hazra, Chinmoy K.; Gandhamsetty, Narasimhulu; Park, Sehoon; Chang, Sukbok

    2016-11-01

    The conversion of renewable biomass resources to synthetically valuable chemicals is highly desirable, but remains a formidable challenge in regards to the substrate scope and reaction conditions. Here we present the development of tris(pentafluorophenyl)borane-catalysed conversion of furans via ring-opening and closing cascade processes to afford silicon-functionalized synthetic chemicals under transition metal-free conditions. The furan ring-opening with hydrosilanes is highly efficient (TON up to 2,000) and atom-economical without forming any byproduct to give rise to α-silyloxy-(Z)-alkenyl silanes. Additional equivalents of silane smoothly induce a subsequent B(C6F5)3-catalysed cyclization of initially formed olefinic silane compounds to produce anti-(2-alkyl)cyclopropyl silanes, another versatile synthon being potentially applicable in the synthesis of natural products and pharmacophores.

  12. Modulation of population density and size of silver nanoparticles embedded in bacterial cellulose via ammonia exposure: visual detection of volatile compounds in a piece of plasmonic nanopaper

    Science.gov (United States)

    Heli, B.; Morales-Narváez, E.; Golmohammadi, H.; Ajji, A.; Merkoçi, A.

    2016-04-01

    The localized surface plasmon resonance exhibited by noble metal nanoparticles can be sensitively tuned by varying their size and interparticle distances. We report that corrosive vapour (ammonia) exposure dramatically reduces the population density of silver nanoparticles (AgNPs) embedded within bacterial cellulose, leading to a larger distance between the remaining nanoparticles and a decrease in the UV-Vis absorbance associated with the AgNP plasmonic properties. We also found that the size distribution of AgNPs embedded in bacterial cellulose undergoes a reduction in the presence of volatile compounds released during food spoilage, modulating the studied nanoplasmonic properties. In fact, such a plasmonic nanopaper exhibits a change in colour from amber to light amber upon the explored corrosive vapour exposure and from amber to a grey or taupe colour upon fish or meat spoilage exposure. These phenomena are proposed as a simple visual detection of volatile compounds in a flexible, transparent, permeable and stable single-use nanoplasmonic membrane, which opens the way to innovative approaches and capabilities in gas sensing and smart packaging.The localized surface plasmon resonance exhibited by noble metal nanoparticles can be sensitively tuned by varying their size and interparticle distances. We report that corrosive vapour (ammonia) exposure dramatically reduces the population density of silver nanoparticles (AgNPs) embedded within bacterial cellulose, leading to a larger distance between the remaining nanoparticles and a decrease in the UV-Vis absorbance associated with the AgNP plasmonic properties. We also found that the size distribution of AgNPs embedded in bacterial cellulose undergoes a reduction in the presence of volatile compounds released during food spoilage, modulating the studied nanoplasmonic properties. In fact, such a plasmonic nanopaper exhibits a change in colour from amber to light amber upon the explored corrosive vapour exposure and

  13. DFT investigation on dihydrogen-bonded amine-borane complexes.

    Science.gov (United States)

    Yan, Shihai; Zou, Hongmei; Kang, Wukui; Sun, Lixiang

    2016-01-01

    The DFT method has been employed in the exploration on dihydrogen-bonded amine-borane complexes, with a special emphasis on the dimerization and substituent group effect. Stable dihydrogen bonded complexes can be generated from these amine-borane monomers with the appearance of NH(δ+)…H(δ-)B interactions. The binding energy decreases gradually with the increase of the steric effect of the substituents. The substituent group number mainly varies the C-N bond length. The dimerization generates close H…H and influences predominantly the N-B distance. The effect of dimerization on IR and vibrational circular dichroism (VCD) spectra is stronger than that of the number of substituent groups, which leads to distinct NBO charge variation on α-C. Both the substituent group number and dimerization enhance the chemical shift difference between hydrogen atoms covalently bonded to N and B, Δδ H-H, which can be hired as an index for structural determination. It is proposed that amine-borane complexes with more substituent groups in higher degree of polymerization are potentially interesting materials for hydrogen storage. Graphical Abstract Both the number of substituent group and dimerization enhance the chemical shift difference of hydrogen atoms covalently bonded on N and B, Δδ H-H, which can be employed as an index for the structural determination.

  14. Polyhedral Boranes: A Versatile Building Block for Nanoporous Materials

    Science.gov (United States)

    Clingerman, Daniel Jon

    The studies described in this dissertation examine several new concepts related to polyhedral boranes and their applications towards the synthesis of novel nanoporous materials. The unique thermal and chemical robustness, rigidity, quasi-spherical geometry, and high boron content of polyhedral boranes are explored to generate materials not possible with typical organic synthons. Aside from the fundamental synthetic work, this work was also aimed at solving larger global issues such as energy storage and new routes to therapeutics. Chapter 2 highlights the discovery of the first highly porous carborane-based metal-organic framework, where the spherical nature of the carborane increases volumetric surface area without reducing pore volume. Chapter 3 examines the first tritopic carborane-based ligand and the stabilizing effect the rigid, sterically bulky carboranyl groups have on highly porous topologies not stable with typical organic ligands. Chapters 4 and 5 describe the use of polyhedral borane-based ligands as a means to influence and generate unexpected topologies. Lastly, chapter 6 explores using a simple carborane-based ligand that harnesses the power of coordination-driven assembly to rapidly generate a high boron-containing supramolecular cuboctahedron.

  15. 无氨复合凝胶的制备及其胶凝特性%Synthesis of Ammonia-free Compound Gel and Its Gelation Characterization

    Institute of Scientific and Technical Information of China (English)

    于水军; 贾博宇; 兀帅东

    2011-01-01

    In order to improve fire extinguishing properties and thermal stability of gel, the gelation characteristics of ammonia-free compound gel were investigated by photoelectric analysis.The gelling time of ammonia-free compound gel was measured by photoelectric method and the effect of temperature on gelling time of compound gel was analyzed and the thermal stability of plain gel and compound gel were compared with each other in different environments.The results show that the gelling time of compound gel shortens rapidly with temperature increasing and the influence of environmental temperature on the gelling time has a relationship with the mass fraction of compound gel, the degree of influence is that 6% gelatinizing agent>8% gelatinizing agent>10% gelatinizing agent.Adding gelling agent composed of varied complex Lewis acid to Na2SiO3·nH2O solution could counteract the charge of the micelle silicate, damage the fusion membrane of the micelle silicate, and promote colloidal particle coagulation in order to convert into full of flexibility.Because the composite gelling agent is crushing polyhedron, the increases of specific surface area and water absorption improve the thermal stability of the gel.%为了提高凝胶的防灭火性能及热稳定性,用光电分析法研究了新型无氨复合凝胶的胶凝特性.采用光电法测出无氨复合凝胶的成胶时间,分析温度对复合凝胶成胶时间影响,并在同环境下对比了普通凝胶和复合凝胶的热稳定性.结果表明,复合凝胶的成胶时间随环境温度的升高而缩短,且环境温度对成胶时间的影响程度与复合胶凝剂的质量分数有关,影响程度为:6%的胶凝剂>8%的胶凝剂>10%的胶凝剂.NaSiO·nHO溶液中添加含有多种Lewis酸的复合胶凝剂后,中和了硅酸胶团的电荷,破坏硅酸胶团的融合膜,促使胶粒发生沉聚而转变为有弹性的凝胶,并且复合胶凝剂的粒度为破碎多面体,进而增加了比表面

  16. Simple unprecedented conversion of phosphine oxides and sulfides to phosphine boranes using sodium borohydride.

    Science.gov (United States)

    Rajendran, Kamalraj V; Gilheany, Declan G

    2012-01-21

    A variety of phosphine oxides and sulfides can be efficiently converted directly to the corresponding phosphine boranes using oxalyl chloride followed by sodium borohydride. Optically active P-stereogenic phosphine oxides can be converted stereospecifically to phosphine boranes with inversion of configuration by treatment with Meerwein's salt followed by sodium borohydride.

  17. Difluoro[2-(quinolin-2-ylphenolato]borane

    Directory of Open Access Journals (Sweden)

    Xi Yang

    2011-05-01

    Full Text Available The title compound, C15H10BF2NO, was synthesized by the reaction of 2-(quinolin-2-ylphenol and boron trifluoride etherate. The quinoline ring system and the benzene ring are twisted, making a dihedral angle of 8.3 (2°. In the crystal, π–π interactions between the aromatic rings [centroid–centroid distance = 3.638 (9 Å] link the molecules into chains propagating in [100].

  18. Determination of ammonia and primary amine compounds and Kjeldahl nitrogen in water samples with a modified Roth's fluorimetric method.

    Science.gov (United States)

    Lloret, S Meseguer; Andrés, J Verdú; Legua, C Molins; Falcó, P Campíns

    2005-02-28

    A method for the simultaneous determination of primary amino groups and ammonium ion has been proposed. The method is based in solution derivatization with o-Phthaldialdehyde/N-acetyl-cisteine (OPA/NAC) and fluorescence measurement of the formed isoindols. Analytical characteristics and description of the developed procedure have been provided. The calibration graphs for ammonium (up to 1.44mgL(-1) of N) and methylamine as primary amino model compound (up to 0.282mgL(-1) of N), were obtained. Bivariate and multivariate calibration models have been tested. The limits of detection were 0.07mgL(-1) of N and 0.004mgL(-1) of N for ammonium and amine, respectively. The procedure was first applied directly to standard solutions containing ammonium and amines and secondly to digested solutions by Kjeldahl method. The results obtained allowed to establish the best digestion conditions in order to perform the total amine conversion into ammonium. This procedure has been also applied to real samples (irrigation ditch, residual and fountain waters) and the concentrations of primary amine groups and ammonium have been evaluated. The results obtained after Kjeldahl digestion allowed to estimate the total Kjeldahl N contained in the samples. The samples were also analysed by Nessler method and similar results were obtained.

  19. Efficient synthesis of 1,3,5-oxygenated synthons from dimethyl 3-oxoglutarate: first use of borane-dimethyl sulfide complex as a regioselective reducing agent of 3-oxygenated glutarate derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Riatto, Valeria B.; Carneiro, Maria N.M.; Victor, Mauricio M., E-mail: mmvictor@ufba.b [Universidade Federal da Bahia (IQ/UFBA), Salvador, BA (Brazil). Inst. de Quimica. Dept. de Quimica Organica; Carvalho, Venilia B. [Centro Universitario FIB, Salvador, BA (Brazil). Inst. de Ciencias da Saude

    2011-07-01

    The selective reduction of dimethyl 3-oxoglutarate was accomplished in different levels. A high yielding sodium borohydride reduction of the keto group is fully described leading to dimethyl 3-hydroxyglutarate. When borane-dimethyl sulfide (BMS) complex was used, a diol or a triol compound can be obtained by selective or total reduction of 3-hydroxy- or 3-oxoglutarate, respectively, allowing an efficient and practical route to 1,3,5-oxygenated compounds. (author)

  20. Phenolics and Flavonoids Compounds, Phenylanine Ammonia Lyase and Antioxidant Activity Responses to Elevated CO2 in Labisia pumila (Myrisinaceae

    Directory of Open Access Journals (Sweden)

    Hawa Z.E. Jaafar

    2012-05-01

    Full Text Available A split plot 3 × 3 experiment was designed to examine the impact of three concentrations of CO2 (400, 800 and 1,200 µmol·mol−1 on the phenolic and flavonoid compound profiles, phenylalanine ammonia lyase (PAL and antioxidant activity in three varieties of Labisia pumila Benth. (var. alata, pumila and lanceolata after 15 weeks of exposure. HPLC analysis revealed a strong influence of increased CO2 concentration on the modification of phenolic and flavonoid profiles, whose intensity depended on the interaction between CO2 levels and L. pumila varieties. Gallic acid and quercetin were the most abundant phenolics and flavonoids commonly present in all the varieties. With elevated CO2 (1,200 µmol·mol−1 exposure, gallic acid increased tremendously, especially in var. alata and pumila (101–111%, whilst a large quercetin increase was noted in var. lanceolata (260%, followed closely by alata (201%. Kaempferol, although detected under ambient CO2 conditions, was undetected in all varieties after exposure. Instead, caffeic acid was enhanced tremendously in var. alata (338~1,100% and pumila (298~433%. Meanwhile, pyragallol and rutin were only seen in var. alata (810 µg·g−1 DW and pumila (25 µg·g−1 DW, respectively, under ambient conditions; but the former compound went undetected in all varieties while rutin continued to increase by 262% after CO2 enrichment. Interestingly, naringenin that was present in all varieties under ambient conditions went undetected under enrichment, except for var. pumila where it was enhanced by 1,100%. PAL activity, DPPH and FRAP also increased with increasing CO2 levels implying the possible improvement of health-promoting quality of Malaysian L. pumila

  1. Simple unprecedented conversion of phosphine oxides and sulfides to phosphine boranes using sodium borohydride

    OpenAIRE

    2012-01-01

    A variety of phosphine oxides and sulfides can be efficiently converted directly to the corresponding phosphine boranes using oxalyl chloride followed by sodium borohydride. Optically active P-stereogenic phosphine oxides can be converted stereospecifically to phosphine boranes with inversion of configuration by treatment with Meerwein's salt followed by sodium borohydride.

  2. Kinetics of electroless deposition: the copper-dimethylamine borane system.

    Science.gov (United States)

    Plana, Daniela; Campbell, Andrew I; Patole, Samson N; Shul, Galyna; Dryfe, Robert A W

    2010-06-15

    A kinetic study of the electroless deposition of copper on gold, using dimethylamine borane (DMAB) as a reducing agent, has been carried out. The copper deposition rate in the electroless bath was determined to be 50 nm min(-1), through electrochemical stripping of the copper deposits as well as from direct measurements of the film thickness using atomic force microscopy (AFM). Comparison with a galvanic cell setup, where the two half-reactions were physically separated, yielded a lower deposition rate of 30 nm min(-1). An important kinetic effect of the surface on the oxidation of the reducing agent, and thus on the overall process, was therefore revealed. The efficiency of the process was measured over time, revealing the contribution of side reactions in the cathodic half-cell, particularly during the initial stages of the electroless process.

  3. Tetraammineplatinum(II dichloride ammonia tetrasolvate

    Directory of Open Access Journals (Sweden)

    Tobias Grassl

    2014-07-01

    Full Text Available The title compound, [Pt(NH34]Cl2·4NH3, was crystallized in liquid ammonia from the salt PtCl2. The platinum cation is coordinated by four ammonia molecules, forming a square-planar complex. The chloride anions are surrounded by nine ammonia molecules, either bound within the platinum complex or solvent molecules. The solvent ammonia molecules are packed in such a way that an extended network of N—H...N and N—H...Cl hydrogen bonds is formed. The structure is isotypic with [Pd(NH34]Cl2·4NH3 [Grassl & Korber (2014. Acta Cryst. E70, i32].

  4. Solid amine-boranes as high performance hypergolic hybrid rocket fuels

    Science.gov (United States)

    Pfeil, Mark A.

    Hypergolic hybrid rockets have the potential of providing systems that are simple, reliable, have high performance, and allow for energy management. Such a propulsion system can be applied to fields that need a single tactical motor with flexible mission requirements of either high speed to target or extended loitering. They also provide the possibility for alternative fast response dynamic altitude control systems if ignition delays are sufficiently short. Amines are the traditional fuel of choice when selecting a hypergolic combination as these tend to react readily with both nitric acid and dinitrogen tertroxide based oxidizers. It has been found that the addition of a borane adduct to an amine fuel tends to reduce the ignition delay by up to an order of magnitude with white fuming nitric acid (WFNA). The borane addition has resulted in fuels with very short ignition delays between 2-10 ms - the fastest times for an amine based fuel reacting with nitric acid based oxidizers. The incorporation of these amine-boranes, specifically ethylenediamine bisborane (EDBB), into various fuel binders has also been found to result in ignition delays between 3-10 ms - the fastest times again for amine based fuels. It was found that the addition of a borane to an amine increased theoretical performance of the amine resulting in high performance fuels. The amine-borane/fuel binder combinations also produced higher theoretical performance values than previously used hypergolic hybrid rockets. Some of the theoretical values are on par or higher than the current toxic liquid hypergolic fuels, making amine boranes an attractive replacement. The higher performing amine-borane/fuel binder combinations also have higher performance values than the traditional rocket fuels, excluding liquid hydrogen. Thus, amine-borane based fuels have the potential to influence various area in the rocket field. An EDBB/ferrocene/epoxy fuel was tested in a hypergolic hybrid with pure nitric acid as the

  5. Intracellular disulfide reduction by phosphine-borane complexes: Mechanism of action for neuroprotection.

    Science.gov (United States)

    Niemuth, Nicholas J; Thompson, Alex F; Crowe, Megan E; Lieven, Christopher J; Levin, Leonard A

    2016-10-01

    Phosphine-borane complexes are novel cell-permeable drugs that protect neurons from axonal injury in vitro and in vivo. These drugs activate the extracellular signal-regulated kinases 1/2 (ERK1/2) cell survival pathway and are therefore neuroprotective, but do not scavenge superoxide. In order to understand the interaction between superoxide signaling of neuronal death and the action of phosphine-borane complexes, their biochemical activity in cell-free and in vitro assays was studied by electron paramagnetic resonance (EPR) spectrometry and using an intracellular dithiol reporter that becomes fluorescent when its disulfide bond is cleaved. These studies demonstrated that bis(3-propionic acid methyl ester) phenylphosphine-borane complex (PB1) and (3-propionic acid methyl ester) diphenylphosphine-borane complex (PB2) are potent intracellular disulfide reducing agents which are cell permeable. EPR and pharmacological studies demonstrated reducing activity but not scavenging of superoxide. Given that phosphine-borane complexes reduce cell injury from mitochondrial superoxide generation but do not scavenge superoxide, this implies a mechanism where an intracellular superoxide burst induces downstream formation of protein disulfides. The redox-dependent cleavage of the disulfides is therefore a novel mechanism of neuroprotection.

  6. Iridium-catalysed dehydrocoupling of aryl phosphine-borane adducts: synthesis and characterisation of high molecular weight poly(phosphinoboranes).

    Science.gov (United States)

    Paul, Ursula S D; Braunschweig, Holger; Radius, Udo

    2016-06-30

    The thermal dehydrogenative coupling of aryl phosphine-borane adducts with iridium complexes bearing a bis(phosphinite) pincer ligand is reported. This catalysis produces high molecular weight poly(phosphinoboranes) [ArPH-BH2]n (Ar = Ph, (p)Tol, Mes). Furthermore, we investigated the reactivity of these pincer complexes towards primary phosphines and their respective borane adducts on a stoichiometric scale.

  7. The lithiation and acyl transfer reactions of phosphine oxides, sulfides and boranes in the synthesis of cyclopropanes

    DEFF Research Database (Denmark)

    Clarke, Celia; Fox, David J; Pedersen, Daniel Sejer;

    2009-01-01

    Phosphine oxides are lithiated much faster than phosphine sulfides and phosphine boranes. Phosphine sulfides are in turn lithiated much more readily than phosphine boranes. It was possible to trap a phosphine sulfide THF in one case which upon treatment with t-BuOK gave cyclopropane, showing that...

  8. Syntheses and structures of dimeric sodium and potassium complexes of 2,6-diisopropyl-anilidophosphine borane ligand

    Indian Academy of Sciences (India)

    Kishor Naktode; Jayeeta Bhattacharjee; Anirban Chakrabarti; Tarun K Panda

    2015-02-01

    We report here the syntheses and structural studies of dimeric sodium and potassium complexes of composition [Na(THF)2{Ph2P(BH3)N(2,6-iPr2C6H6)}]2 (2) and [K(THF)2{Ph2P(BH3)N(2,6-iPr2C6H6)}]2(3). The sodium complex 2 was readily prepared by the reaction of sodium bis(trimethylsilyl)amide with 2,6-diisopropylanilidophosphine-borane ligand [2,6-iPr2C6H3NHP(BH3)Ph2] (1-H) at ambient temperature. The potassium complex 3 was prepared by two synthetic routes: in the first method, the ligand 1-H was made to react with potassium hydride at room temperature to afford the corresponding potassium complex. The potassium bis(trimethylsilyl)amides were made to react with protic ligand 1-H in the second method to eliminate the volatile bis(trimethyl)silyl amine. Solid-state structures of both the new complexes were established by single crystal X-ray diffraction analysis. In the molecular structures of complexes 2, the sodium metal is coordinated by the anilido nitrogen (1) and borane group (1) attached to the phosphorus atom of ligand 1. In contrast, for compound 2, ligand 1 displays 6-arene interaction from 2,6-diisopopylphenyl ring with potassium atom along with 3 interaction of BH3 group due to larger ionic radius of potassium ion.

  9. Effects of Dimethylamine Borane in Electroless Ni-B Plating.

    Science.gov (United States)

    Rha, Sa-Kyun; Baek, Seung-Deok; Lee, Youn-Seoung

    2015-10-01

    By electroless plating in a pH 7 bath at 50 °C, Ni-B alloy films with nano-crystallite size (3-6 nm) were formed on screen printed Ag paste. According to the addition of DMAB (dimethylamine borane), the boron concentration in the Ni-B alloy films increased systematically from <1 at.% to ~10 at.%, and the crystallite size of the Ni-B alloy films decreased gradually. The crystal/electronic structures of the Ni-B alloys were studied using XAS (X-ray absorption spectroscopy), XRD, etc., with changes of boron contents. In the crystalline structure, the ordering of fcc type was broken upon alloying and then the samples with additions of 0.5 M and 1 M DMAB had amorphous-like structures with decreases of crystallite size. In the electronic structure, the unoccupied d states of the Ni sites were filled as the B concentration increased upon alloying. From the electronegativity rule and the broken orderging upon alloying, we can suggest that an overall charge transfer occurs from the Ni sites toward the alloying B sites with intra-atomic charge redistribution, leading to an increased occupancy of the Ni 3d states in the alloys.

  10. Ammonia abatement by slurry acidification

    DEFF Research Database (Denmark)

    Petersen, Søren O.; Hutchings, Nicholas John; Hafner, Sasha

    2016-01-01

    Livestock production systems can be major sources of trace gases including ammonia (NH3), the greenhouse gases methane (CH4) and nitrous oxide (N2O), and odorous compounds such as hydrogen sulphide (H2S). Short-term campaigns have indicated that acidification of livestock slurry during in...... sections with 30-32 pigs with or without daily adjustment of slurry pH to below 6. Ammonia losses from reference sections with untreated slurry were between 9.5 and 12.4% of N excreted, and from sections with acidified slurry between 3.1 and 6.2%. Acidification reduced total emissions of NH3 by 66 and 71...

  11. Ni→B Interactions in Nickel Phosphino-Alkynyl-Borane Complexes

    NARCIS (Netherlands)

    Zhao, Xiaoxi; Otten, Edwin; Song, Datong; Stephan, Douglas W.

    2010-01-01

    The Ni complexes [{tBu2PC≡CB(C6F5)2}Ni(cod)] and [({tBu2PC≡CB(C6F5)2}Ni(NCMe))2] derived from the reaction between the phosphino-alkynyl-borane tBu2PC≡CB(C6F5)2 and [Ni(cod)2] exhibit an unprecedented metal–alkyne interaction in which the borane substituent bends towards the metal affording a Ni→B d

  12. A New Homogeneous Catalyst for the Dehydrogenation of Dimethylamine Borane Starting with Ruthenium(III Acetylacetonate

    Directory of Open Access Journals (Sweden)

    Ebru Ünel Barın

    2015-06-01

    Full Text Available The catalytic activity of ruthenium(III acetylacetonate was investigated for the first time in the dehydrogenation of dimethylamine borane. During catalytic reaction, a new ruthenium(II species is formed in situ from the reduction of ruthenium(III and characterized using UV-Visible, Fourier transform infrared (FTIR, 1H NMR, and mass spectroscopy. The most likely structure suggested for the ruthenium(II species is mer-[Ru(N2Me43(acacH]. Mercury poisoning experiment indicates that the catalytic dehydrogenation of dimethylamine-borane is homogeneous catalysis. The kinetics of the catalytic dehydrogenation of dimethylamine borane starting with Ru(acac3 were studied depending on the catalyst concentration, substrate concentration and temperature. The hydrogen generation was found to be first-order with respect to catalyst concentration and zero-order regarding the substrate concentration. Evaluation of the kinetic data provides the activation parameters for the dehydrogenation reaction: the activation energy Ea = 85 ± 2 kJ·mol−1, the enthalpy of activation ∆H# = 82 ± 2 kJ·mol−1 and the entropy of activation; ∆S# = −85 ± 5 J·mol−1·K−1. The ruthenium(II catalyst formed from the reduction of ruthenium(III acetylacetonate provides 1700 turnovers over 100 hours in hydrogen generation from the dehydrogenation of dimethylamine borane before deactivation at 60 °C.

  13. Intermediates in the Rh-catalysed dehydrocoupling of phosphine-borane.

    Science.gov (United States)

    Huertos, Miguel A; Weller, Andrew S

    2012-07-21

    Active species, product distributions and a suggested catalytic cycle are reported for the dehydrocoupling of the phosphine-borane H(3)B·P(t)Bu(2)H to give HP(t)Bu(2)BH(2)P(t)Bu(2)BH(3) using the [Rh(COD)(2)][BAr(F)(4)] pre-catalyst.

  14. Ammonia production, excretion, toxicity, and defense in fish: A Review

    Directory of Open Access Journals (Sweden)

    Alex Y K Ip

    2010-10-01

    Full Text Available Many fishes are ammonotelic but some species can detoxify ammonia to glutamine or urea. Certain fish species can accumulate high levels of ammonia in the brain or defense against ammonia toxicity by enhancing the effectiveness of ammonia excretion through active NH4+ transport, manipulation of ambient pH, or reduction in ammonia permeability through the branchial and cutaneous epithelia. Recent reports on ammonia toxicity in mammalian brain reveal the importance of permeation of ammonia through the blood-brain barrier and passages of ammonia and water through transporters in the plasmalemma of brain cells. Additionally, brain ammonia toxicity could be related to the passage of glutamine through the mitochondrial membranes into the mitochondrial matrix. On the other hand, recent reports on ammonia excretion in fish confirm the involvement of Rhesus glycoproteins in the branchial and cutaneous epithelia. Therefore, this review focuses on both the earlier literature and the up-to-date information on the problems and mechanisms concerning the permeation of ammonia, as NH3, NH4+ or proton-neutral nitrogenous compounds, across mitochondrial membranes, the blood-brain barrier, the plasmalemma of neurons, and the branchial and cutaneous epithelia of fish. It also addresses how certain fishes with high ammonia tolerance defend against ammonia toxicity through the regulation of the permeation of ammonia and related nitrogenous compounds through various types of membranes. It is hoped that this review would revive the interests in investigations on the passage of ammonia through the mitochondrial membranes and the blood-brain barrier of ammonotelic fishes and fishes with high brain ammonia-tolerance, respectively.

  15. 氧化铁改性石英砂的复合挂膜与氨氮去除试验研究%EXPERIMENTAL STUDY ON COMPOUND FORMATION AND REMOVAL AMMONIA NITROGEN USING IRON OXIDE COATED SANDS

    Institute of Scientific and Technical Information of China (English)

    李冬梅; 刘贝; 庞治星; 刘培涛; 刘雄威; 李绍秀

    2012-01-01

    采用自制的氧化铁改性石英砂滤料(简称“改性砂”),对生物改性砂联合处理微污染物氨氮的复合挂膜启动性能以及滤料表面形态进行了试验研究,并与生物普通砂联用效果进行对比.结果表明,生物普通砂和生物改性砂在挂膜初期的生物量分别为15.46、13.79 nmol/g(n(P)/m(滤料)),稳定运行期分别为18.75、20.09 nmol/g;挂膜初期,生物普通砂与生物改性砂对质量浓度为1~2 mg/L氨氮的去除效果分别达到92%和95%;挂膜稳定期,前者对氨氮的去除效果约60%,后者稳定在80%左右;在不同氨氮质量浓度(0.5~4 mg/L)下,生物普通砂对氨氮去除率从60%上升至80%,生物改性砂的去除率从70%增至95%;过滤前后2种滤料表面形态均发生变化,生物改性砂表面孔隙更小,结构更加复杂多孔,表面粗糙程度进一步增加,对氨氮去除率高.%A homemade iron oxide cCoated sands filters with biological was used to remove ammonia nitrogen from contaminated source water, the process of compound formation start-up and the surface morphology of the two filters was carried out, and contrasted with the effect of biological-raw sands. The results were shown as follows: The biomass of the biological- raw sand filter, and biological-iron oxide coated sand filter were 15.46 and 13.79 nmol/g in the initial of formation, 18.75 and 20.09 nmol/g in the stable of formation. Removal of ammonia nitrogen with concentration among 1.0-2.0 mg/L using biological-raw sands and biological-iron oxide coated sands were 92% to 95% in the initial of formation, In the stable of formation, removal ammonia nitrogen using biological-raw sands stable about 60%, and removal ammonia nitrogen using biological-iron oxide coated sands stable about 80%. In different concentrations of ammonia nitrogen among 0.5~4.0 mg/L, removal efficiency of biological-raw sands from 60% rose to 80%, biological- iron oxide coated sands from 70% rose to

  16. Uptake of [sup 10]B in gliosarcomas following the injection of gluthathione monoethyl ester and sulfhydryl borane

    Energy Technology Data Exchange (ETDEWEB)

    Joel, D.D.; Slatkin, D.N.; Coderre, J.A.

    1992-01-01

    The sulfhydryl borane Na[sub 2][sup 10]B[sub 12]H[sub 11]SH (BSH) was developed as a capture agent for BNCT about 20 years ago and is the compound currently used clinically in Japan for BNCT of malignant brain tumors. Tumor [sup 10]B concentrations following the infusion of the oxidized BSH, a disulfide dimer (Na[sub 4][sup 10]B[sub 24]H[sub 22]S[sub 2]), are nearly twice those obtained following administration of equal amounts of boron as BSH. Also, the rate of decrease of tumor [sup 10]B concentration is slower after dimer infusion than after BSH infusion. When BNCT was administered to rats bearing intracerebral gliosarcomas, the animals infused with dimer had a significant longer median survival time. Dimer, on the other hand, induces a moderately severe, but reversible, hepatotoxicity which may complicate its use in humans. Intracellular glutathione plays an important role in defense against radical-mediated tissue injury. Glutathione monoesters have been reported to have a protective effective on cisplatin toxicity and on radical-induced acute pancreatitis. We investigated the possibility of reducing dimer-induced hepatotoxicity by pre-administration of GSH-ME. The results indicate that not only does the pre-administration of GSH-ME markedly reduce dimer-induced hepatotoxicity, but also results in nearly a doubling of tumor boron concentration. Furthermore, GSH-ME markedly increases tumor boron uptake and retention following administration of BSH.

  17. Uptake of {sup 10}B in gliosarcomas following the injection of gluthathione monoethyl ester and sulfhydryl borane

    Energy Technology Data Exchange (ETDEWEB)

    Joel, D.D.; Slatkin, D.N.; Coderre, J.A.

    1992-12-31

    The sulfhydryl borane Na{sub 2}{sup 10}B{sub 12}H{sub 11}SH (BSH) was developed as a capture agent for BNCT about 20 years ago and is the compound currently used clinically in Japan for BNCT of malignant brain tumors. Tumor {sup 10}B concentrations following the infusion of the oxidized BSH, a disulfide dimer (Na{sub 4}{sup 10}B{sub 24}H{sub 22}S{sub 2}), are nearly twice those obtained following administration of equal amounts of boron as BSH. Also, the rate of decrease of tumor {sup 10}B concentration is slower after dimer infusion than after BSH infusion. When BNCT was administered to rats bearing intracerebral gliosarcomas, the animals infused with dimer had a significant longer median survival time. Dimer, on the other hand, induces a moderately severe, but reversible, hepatotoxicity which may complicate its use in humans. Intracellular glutathione plays an important role in defense against radical-mediated tissue injury. Glutathione monoesters have been reported to have a protective effective on cisplatin toxicity and on radical-induced acute pancreatitis. We investigated the possibility of reducing dimer-induced hepatotoxicity by pre-administration of GSH-ME. The results indicate that not only does the pre-administration of GSH-ME markedly reduce dimer-induced hepatotoxicity, but also results in nearly a doubling of tumor boron concentration. Furthermore, GSH-ME markedly increases tumor boron uptake and retention following administration of BSH.

  18. Ammonia distribution and excretion in fish.

    Science.gov (United States)

    Randall, D J; Wright, P A

    1987-05-01

    This paper reviews the literature concerning ammonia production, storage and excretion in fish. Ammonia is the end product of protein catabolism and is stored in the body of fish in high concentrations relative to basal excretion rates. Ammonia, if allowed to accumulate, is toxic and is converted to less toxic compounds or excreted. Like other weak acids and bases, ammonia is distributed between tissue compartments in relation to transmembrane pH gradients. NH3 is generally equilibrated between compartments but NH4 (+) is distributed according to pH. Ammonia is eliminated from the blood upon passage through the gills. The mechanisms of branchial ammonia excretion vary between different species of fish and different environments, and primarily involves NH3 passive diffusion and NH4 (+)/Na(+) exchange. Water chemistry near the gill surface may also be important to ammonia excretion, but a more accurate measurement of the NH3 gradient across the gill epithelium is required before a more detailed analysis of NH3 and NH4 (+) excretion can be made.

  19. WOOD COLOR CHANGES BY AMMONIA FUMING

    Directory of Open Access Journals (Sweden)

    Josip Miklečić,

    2012-06-01

    Full Text Available This paper studies the influence of ammonia gas on wood color changes in response to an increasing demand for dark colored wood specimens. The darker wood color in ammonia fuming is accomplished through chemical reactions between ammonia gas and wood compounds. We exposed oak, maple, spruce, and larch wood samples to ammonia gas for 16 days. During fuming, the color changes were studied using CIE L*a*b* parameters. After fuming, the changes in extractives content, tannin, and nitrogen content were analyzed. The chemical changes of wood and residues of wood extractives after fuming were analyzed by FTIR spectroscopy. Oak wood reacted intensively with ammonia gas in a very short time, and the darkening was prominent for all the investigated wood species. It was established that tannin had no major influence on color changes of maple and larch wood in the ammonia-fuming process. The FTIR spectra of fumed wood indicated involvement of carbonyl groups, and the FTIR spectra of wood extractives indicated involvement of carbonyl, aromatic, and alcohol groups in reaction with ammonia gas.

  20. Density functional study on enantioselective reduction of keto oxime ether with borane catalyzed by oxazaborolidine

    Institute of Scientific and Technical Information of China (English)

    LI; Ming; ZHENG; Wenxu

    2006-01-01

    The enantioselective reduction of keto oxime ether with borane catalyzed by oxazaborolidine is discussed by the density functional theory (DFT) method. The main intermediates and transition states for this reaction are optimized completely at the B3LYP/6-31g(d) level, and the transition states are verified by vibrational modes. As shown, the chirality-controlled steps for this reaction are the hydride transfer from borane to carbonyl carbon and oxime carbon of keto oxime ether, and the chirality for the reduced products is determined in these two reaction steps. In all examined reaction paths, the first hydride is transferred via a six-membered ring and the second hydride via a five-membered ring or a four-membered ring.

  1. Compound fault diagnosis of liquid ammonia tank car based on probabilistic neural network%基于概率神经网络的液氨汽车罐车复合故障诊断

    Institute of Scientific and Technical Information of China (English)

    马成正

    2011-01-01

    Fault diagnosis is important to ensure the safety of hazardous chemical tank car' transportation. From the requirements of transportation security, based on the structural features of liquid ammonia tank car and the requirements of laws in domestics, the fault signature parameters of liquid ammonia tank car were analyzed ali sidedly.The parameters were established as input nodes of probabilistic neural network. According to the fault classification in view of the facts, the fault tolerant and adaptive abilities of fault diagnosis were considered to structure the compound fault diagnosis model based on probabilistic neural network. Using index parameters as the network training samples, the unknown failure modes were diagnosed. The proposed method was applied to prove the liquid ammonia sense data which provided by pressure vessel inspection of Guangxi area. The result indicated that the model has the advantages of the clear physical concepts and high precision, so the used method is feasible and rational.The work specified in this paper can be as reference to the compound fault diagnosis of hazardous chemical tank car.%故障诊断在保证危险化学品汽车罐车运输安全方面具有重要意义.从国内交通运输安全的实际要求出发,依据液氨汽车罐车的结构特点及国家法律法规的要求,比较全面、系统地分析了液氨汽车罐车故障特征的相关参数,并将其作为概率神经网络的输入结点.根据实际可能发生的故障分类模式,考虑到故障诊断的容错能力和自适应能力,提出了基于概率神经网络的复合故障诊断模型.利用指标参数作为网络训练样本,对未知故障模式进行诊断,并以广西地区压力容器检验所液氨检测数据为例进行说明.理论分析和实例计算表明,该模型物理概念清晰,计算结果合理,精度较高,在危险化学品汽车罐车故障诊断中有很好的适用性.该项工作可为我国危险化学品汽车罐车

  2. Smallpox inoculation (variolation) in East Africa with special reference to the practice among the Boran and Gabra of Northern Kenya.

    Science.gov (United States)

    Imperato, Pascal James; Imperato, Gavin H

    2014-12-01

    Smallpox inoculation (variolation) was widely reported in sub-Sahara Africa before, during, and after the colonial era. The infective smallpox materials and techniques used, as well as the anatomical sites for inoculation, varied widely among different ethnic groups. The practice among the Boran and Gabra pastoralists of northern Kenya resembled that which was prevalent in a number of areas of Ethiopia. This is not surprising as the Boran also live in southern Ethiopia, and Gabra herdsmen frequently cross the border into this region. The Boran and Gabra technique for smallpox inoculation consisted of taking infective material from the vesicles or pustules of those with active smallpox, and scraping it into the skin on the dorsum of the lower forearm. Although the intent was to cause a local reaction and at most a mild form of smallpox, severe cases of the disease not infrequently resulted. Also, variolated individuals were capable of infecting others with smallpox, thereby augmenting outbreaks and sustaining them. The limited known reports of smallpox inoculation among the Boran and Gabra are presented in this communication. The expansion of vaccination with effective heat stable vaccines, the development of medical and public health infrastructures, and educational programs all contributed to the eventual disappearance of the practice among the Boran and Gabra.

  3. Mechanism of phosphine borane deprotection with amines: the effects of phosphine, solvent and amine on rate and efficiency.

    Science.gov (United States)

    Lloyd-Jones, Guy C; Taylor, Nicholas P

    2015-03-27

    The kinetics of borane transfer from simple tertiary phosphine borane adducts to a wide range of amines have been determined. All data obtained, including second-order kinetics, lack of cross-over, and negative entropies of activation for reaction of triphenylphosphine borane with quinuclidine and triethylamine, are consistent with a direct (SN 2-like) transfer process, rather than a dissociative (SN 1-like) process. The identities of the amine, phosphine, and solvent all impact substantially on the rate (k) and equilibrium (K) of the transfer, which in some cases vary by many orders of magnitude. P-to-N transfer is more efficient with cyclic amines in apolar solvents due to reduced entropic costs and ground-state destabilisation. Taken as a whole, the data allow informed optimisation of the deprotection step from the stand-point of rate, or synthetic convenience. In all cases, both reactants should be present at high initial concentration to gain kinetic benefit from the bimolecularity of the process. Ultimately, the choice of amine is dictated by the identity of the phosphine borane complex. Aryl-rich phosphine boranes are sufficiently reactive to allow use of diethylamine or pyrrolidine as a volatile low polarity solvent and reactant, whereas more alkyl-rich phosphines benefit from the use of more reactive amines, such as 1,4-diaza[2.2.2]bicyclooctane (DABCO), in apolar solvents at higher temperatures.

  4. An Intramolecular Silylene Borane Capable of Facile Activation of Small Molecules, Including Metal-Free Dehydrogenation of Water.

    Science.gov (United States)

    Mo, Zhenbo; Szilvási, Tibor; Zhou, Yu-Peng; Yao, Shenglai; Driess, Matthias

    2017-02-27

    The first single-component N-heterocyclic silylene borane 1 (LSi-R-BMes2 ; L=PhC(N(t) Bu)2 ; R=1,12-xanthendiyl spacer; Mes=2,4,6-Me3 C6 H2 ), acting as a frustrated Lewis pair (FLP) in small-molecule activation, can be synthesized in 65 % yields. Its HOMO is largely localized at the silicon(II) atom and the LUMO has mainly boron 2p character. In small-molecule activation 1 allows access to the intramolecular silanone-borane 3 featuring a Si=O→B interaction through reaction with O2 , N2 O, or CO2 , and formation of silanethione borane 4 from reaction with S8 . The Si(II) center in 1 undergoes immediate hydrogenation if exposed to H2 at 1 atm pressure in benzene, affording the silane borane 5-H2 , L(H2 )Si-R-BMes2 . Remarkably, no H2 activation occurs if the single silylene LSiPh and Mes3 B intermolecularly separated are exposed to dihydrogen. Unexpectedly, the pre-organized Si-B separation in 1 enables a metal-free dehydrogenation of H2 O to give the silanone-borane 3 as reactive intermediate.

  5. Assessing Ammonia Treatment Options

    Science.gov (United States)

    This is the second of three articles to help water system operators understand ammonia and how to monitor and control its effects at the plant and in the distribution system. The first article (Opflow, April 2012) provided an overview of ammonia's chemistry, origins, and water sy...

  6. Method for forming ammonia

    Science.gov (United States)

    Kong, Peter C.; Pink, Robert J.; Zuck, Larry D.

    2008-08-19

    A method for forming ammonia is disclosed and which includes the steps of forming a plasma; providing a source of metal particles, and supplying the metal particles to the plasma to form metal nitride particles; and providing a substance, and reacting the metal nitride particles with the substance to produce ammonia, and an oxide byproduct.

  7. Catalyst for Ammonia Oxidation

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a bimetallic catalyst for ammonia oxidation, a method for producing a bimetallic catalyst for ammonia oxidation and a method for tuning the catalytic activity of a transition metal. By depositing an overlayer of less catalytic active metal onto a more catalytic...

  8. Computational Search for Improved Ammonia Storage Materials

    DEFF Research Database (Denmark)

    Jensen, Peter Bjerre; Lysgaard, Steen; Vegge, Tejs

    Metal halide ammines, e.g. Mg(NH3)6Cl2 and Sr(NH3)8Cl2, can reversibly store ammonia, with high volumetric hydrogen storage capacities. The storage in the halide ammines is very safe, and the salts are therefore highly relevant as a carbon-free energy carrier in future transportation infrastructure....... In this project we are searching for improved mixed materials with optimal desorption temperatures and kinetics, optimally releasing all ammonia in one step. We apply Density Functional Theory, DFT, calculations on mixed compounds selected by a Genetic Algorithm (GA), relying on biological principles of natural...

  9. Transformation of ammonia i biological airfilters

    DEFF Research Database (Denmark)

    Nielsen, Lars Peter; Sørensen, Karen; Andersen, Mathias;

    2007-01-01

    Ammonia is a major compound in ventilation air from animal houses. In biological filters it is with varying efficiency transformed by physical, biological, and chemical processes and ends up as ammonium, nitrate, and nitrite dissolved in water and as dinitrogen, nitrous oxide and nitric oxide...... emitted to the air. To identify the key regulators of these transformations we have combined data from studies of microbiology and performance in 10 experimental and full scale filters of varying design, loading, and management. Inhibition by nitrite controlled ammonium oxidation and pH, while biological...... nitrite oxidation only appeared in locations with minimal ammonia and nitrite levels. Nitrous oxide emission depended on anoxic microsites, and nitric oxide production was associated with nitrite accumulation. Water and biomass management appear to be the important tools for optimization of ammonia...

  10. Reactor for removing ammonia

    Science.gov (United States)

    Luo, Weifang; Stewart, Kenneth D.

    2009-11-17

    Disclosed is a device for removing trace amounts of ammonia from a stream of gas, particularly hydrogen gas, prepared by a reformation apparatus. The apparatus is used to prevent PEM "poisoning" in a fuel cell receiving the incoming hydrogen stream.

  11. Electron transport and nonlinear optical properties of substituted aryldimesityl boranes: a DFT study.

    Directory of Open Access Journals (Sweden)

    Altaf Hussain Pandith

    Full Text Available A comprehensive theoretical study was carried out on a series of aryldimesityl borane (DMB derivatives using Density Functional theory. Optimized geometries and electronic parameters like electron affinity, reorganization energy, frontiers molecular contours, polarizability and hyperpolarizability have been calculated by employing B3PW91/6-311++G (d, p level of theory. Our results show that the Hammett function and geometrical parameters correlates well with the reorganization energies and hyperpolarizability for the series of DMB derivatives studied in this work. The orbital energy study reveals that the electron releasing substituents increase the LUMO energies and electron withdrawing substituents decrease the LUMO energies, reflecting the electron transport character of aryldimesityl borane derivatives. From frontier molecular orbitals diagram it is evident that mesityl rings act as the donor, while the phenylene and Boron atom appear as acceptors in these systems. The calculated hyperpolarizability of secondary amine derivative of DMB is 40 times higher than DMB (1. The electronic excitation contributions to the hyperpolarizability studied by using TDDFT calculation shows that hyperpolarizability correlates well with dipole moment in ground and excited state and excitation energy in terms of the two-level model. Thus the results of these calculations can be helpful in designing the DMB derivatives for efficient electron transport and nonlinear optical material by appropriate substitution with electron releasing or withdrawing substituents on phenyl ring of DMB system.

  12. Towards chiral diamines as chiral catalytic precursors for the borane-mediated enantioselective reduction of prochiral ketones

    Indian Academy of Sciences (India)

    Deevi Basavaiah; Utpal Das; Suparna Roy

    2009-11-01

    Two chiral diamines (3)-3-anilinomethyl-1,2,3,4-tetrahydroisoquinoline (1) and (2)-2-anilinomethylpiperidine (2) have been employed as chiral catalytic sources in the borane-mediated asymmetric reduction of prochiral ketones thus providing the resulting secondary alcohols in good enantiomeric purities (up to 81% ).

  13. Relations Between Stabilities and Structures of Closo Borane Dianions

    Institute of Scientific and Technical Information of China (English)

    LI Ping

    2006-01-01

    An effective method to investigate the stabilities of a series of new closo-BnHn2-(n = 12, 14, 16, 18, 20, 22, 24, 30) was put forward with the aid of G96PW91/SHC calculations. Stabilities are related to the relative stabilized energies (RSE) and the 2e3c bound geometries of closo-BnHn2-. The structures in which a boron atom connects to four atoms up to seven are stable and appear in many borides because of the lower relative stabilized energy. In geometries, both triangular and quadrangular faces are in favor of forming the structures of closo-BnHn2-. The energies of optimized geometries support the existence of these new compounds. By employing both RSE and ▲E per boron atom in cage, the stabilities were studied to predict the probabilities of unknown clusters in existence. The electron-deficient clusters can be understood that the positive holes should be disperse to every triangular face and lead to share the holes, wherever there are not enough electrons to occupy them. The negative charges which anions carry distribute to 2e3c bonds to increase the stabilities.

  14. Avaliação de fontes de amônia para o tratamento de fenos de gramíneas tropicais. 2. Compostos nitrogenados Evaluation of ammonia sources to tropical grasses hays treatment. 2. Nitrogen compounds

    Directory of Open Access Journals (Sweden)

    Ricardo Andrade Reis

    2001-06-01

    Full Text Available Este estudo foi desenvolvido para se avaliarem as alterações nos conteúdos de compostos nitrogenados dos fenos de braquiária decumbens (Brachiaria decumbnes Stapf e jaraguá (Hyparrhenia rufa Ness Stapf não-tratados, tratados com uréia (U - 5,4% da MS, uréia (UL - 5,4% da MS mais labe-labe (Lablab purpureus L. Sweet, cv. Highworth-3,0% da MS ou amônia anidra (NH3 -3,0% da MS. A aplicação de amônia anidra ou de uréia aumentou os teores de N total, N insolúvel em detergente neutro, N insolúvel em detergente ácido, N não-protéico e N amoniacal. A amonização diminuiu as relações N insolúvel em detergente neutro/N total e N insolúvel em detergente ácido/N total e aumentou as relações N não-protéico/N total, N amoniacal/N total e os teores de PB. O N aplicado foi retido, principalmente, nas formas de NNP e N amoniacal.The experiment was conducted to evaluate the changes on the nitrogen compounds of the Brachiaria decumbens Stapf, jaraguá (Hyparrhenia rufa Ness Stapf grasses hay, untreated, treated with urea (5.4% DM, urea plus lab-lab (UL-5.4% DM plus Lablab purpureus L. Sweet, cv. Highworth-3.0% DM and anhydrous ammonia (NH3 - 3.0% DM. The chemical treatment with urea or NH3 increased the total N, neutral detergent insoluble N 9NDIN, acid detergent insoluble N (ADIN, non nitrogen protein (NNP, and the ammonical nitrogen (AN contents. Ammoniation decreased the NDIN/TN and ADIN/TN ratios. The chemical treatment increased the NNP/TN and NA/TN ratios, and the crude protein contents. The N applied as urea or NH3 was retained as NNP and in the ammoniacal form.

  15. Synthesis, structure, and reactivity of diazene adducts: isolation of iso-diazene stabilized as a borane adduct.

    Science.gov (United States)

    Reiß, Fabian; Schulz, Axel; Villinger, Alexander

    2014-09-08

    This work describes the synthesis and full characterization of a series of GaCl3 and B(C6 F5 )3 adducts of diazenes R(1) NNR(2) (R(1) =R(2) =Me3 Si, Ph; R(1) =Me3 Si, R(2) =Ph). Trans-PhNNPh forms a stable adduct with GaCl3 , whereas no adduct, but instead a frustrated Lewis acid-base pair is formed with B(C6 F5 )3 . The cis-PhNNPh⋅B(C6 F5 )3 adduct could only be isolated when UV light was used, which triggers the isomerization from trans- to cis-PhNNPh, which provides more space for the bulky borane. Treatment of trans-PhNNSiMe3 with GaCl3 led to the expected trans-PhNNSiMe3 ⋅GaCl3 adduct but the reaction with B(C6 F5 )3 triggered a 1,2-Me3 Si shift, which resulted in the formation of a highly labile iso-diazene, Me3 Si(Ph)NN; stabilized as a B(C6 F5 )3 adduct. Trans-Me3 SiNNSiMe3 forms a labile cis-Me3 SiNNSiMe3 ⋅B(C6 F5 )3 adduct, which isomerizes to give the transient iso-diazene species (Me3 Si)2 NN⋅B(C6 F5 )3 upon heating. Both iso-diazene species insert easily into one BC bond of B(C6 F5 )3 to afford hydrazinoboranes. All new compounds were fully characterized by means of X-ray crystallography, vibrational spectroscopy, CHN analysis, and NMR spectroscopy. All compounds were further investigated by DFT and the bonding situation was assessed by natural bond orbital (NBO) analysis.

  16. Techniques for measuring ammonia in fly ash, mortar, and concrete

    Energy Technology Data Exchange (ETDEWEB)

    Rathbone, R.F. [Kentucky Univ., Lexington, KY (United States). Center for Applied Energy Reseach; Majors, R.K. [Boral Material Technologies, Inc., San Antonio, TX (United States). Engineered Materials

    2003-12-01

    The presence of ammonia in fly ash that is to be used in mortar and concrete is of increasing concern in the U.S., mainly due to the installation of selective catalytic reduction (SCR) DeNOx systems. When the SCR catalyst is new, contamination of the fly ash with ammonia is generally not a concern. However, as the catalyst in the SCR ages and becomes less efficient, the ammonia slip increases and results in a greater amount of ammonium salt being precipitated on the fly ash. The increase in ammonia concentration is compounded by variability that can occur on a day-to-day basis. When marketing ammonia-laden fly ash for use in mortar and concrete it is imperative that the concentration of ammonia is known. However, there currently is no widely accepted or ''standard'' method for ammonia measurement in fly ash. This paper describes two methods that have been developed and used by the University of Kentucky Center for Applied Energy Research and Boral Material Technologies, Inc. One of the methods uses gas detection tubes and can provide an accurate determination within five to ten minutes. Thus it is suitable as a rapid field technique. The other method employs a gas-sensing electrode and requires a longer period of time to complete the measurement. However, this second method can also be used to determine the quantity of ammonia in fresh mortar and concrete. (orig.)

  17. On the origin of reversible hydrogen activation by phosphine-boranes.

    Science.gov (United States)

    Rajeev, Ramanan; Sunoj, Raghavan B

    2009-11-23

    Mechanistic insights into the factors responsible for the reversible hydrogen-activation ability exhibited by an aryl phosphine-borane system ((CH(3))(2)P-C(6)F(4)-B(CF(3))(2)) are presented. A detailed evaluation of the energies of various intermediates, generated by the addition of molecular hydrogen, and their interconverting barriers have been carried out using ab initio and DFT methods. Several rearrangement possibilities of the H(2)-phosphino-borane adduct have been investigated so as to unravel the lower energy pathways that convert the initial adduct to a series of other intermediates. The initial adduct formed by the heterolytic addition of a molecular hydrogen across the C-B bond is identified to undergo a series of rearrangement reactions until it terminates at the C-P end of the molecule. Among the possible 1,n-migrations (for which n=1-5), 1,2-proton migrations are found to possess lower energy transition states, whereas 1,2-hydride (in a zwitterionic intermediate) and 1,4-proton-coupled electron transfers exhibited much higher energy transition states. The minimum energy pathway for the transfer of a proton and hydride from the C-B bond to the C-P bond is found to involve a cascade of 1,2-proton transfers followed by a 1,2-hydride migration and finally a 1,4-proton-coupled electron transfer. The higher energy pathways identified for the hydride transfer suggest the possibility of a cascade of reversible proton migrations from a thermodynamically stable intermediate (M(a)). Possible uptake of two hydrogen molecules by the phosphine-borane system is additionally considered in the present study, in which relatively higher barriers than those with one molecule of hydrogen are observed. The computed thermodynamic parameters are found to be in accordance with the experimental observations, in which the uptake and storage of molecular hydrogen are carried out at lower temperatures whereas the liberation demands elevated temperatures.

  18. Fast and Accurate Exhaled Breath Ammonia Measurement

    OpenAIRE

    Solga, Steven F; Mudalel, Matthew L; Spacek, Lisa A.; Risby, Terence H.

    2014-01-01

    This exhaled breath ammonia method uses a fast and highly sensitive spectroscopic method known as quartz enhanced photoacoustic spectroscopy (QEPAS) that uses a quantum cascade based laser. The monitor is coupled to a sampler that measures mouth pressure and carbon dioxide. The system is temperature controlled and specifically designed to address the reactivity of this compound. The sampler provides immediate feedback to the subject and the technician on the quality of the breath effort. Toge...

  19. Ammonia emissions in Europe

    DEFF Research Database (Denmark)

    Jacobsen, Brian H.

    2012-01-01

    The NEC (National Emission Ceiling) directive has set targets for the 2010 ammonia emissions from a number of European countries. The target will be reached by most EU-countries and the total emission for EU-27 has been reduced by 22% from 1990 to 2007. Denmark is one of the countries with the la......The NEC (National Emission Ceiling) directive has set targets for the 2010 ammonia emissions from a number of European countries. The target will be reached by most EU-countries and the total emission for EU-27 has been reduced by 22% from 1990 to 2007. Denmark is one of the countries...

  20. Respiratory ammonia output and blood ammonia concentration during incremental exercise

    NARCIS (Netherlands)

    Ament, W; Huizenga, [No Value; Kort, E; van der Mark, TW; Grevink, RG; Verkerke, GJ

    1999-01-01

    The aim of this study was to investigate whether the increase of ammonia concentration and lactate concentration in blood was accompanied by an increased expiration of ammonia during graded exercise. Eleven healthy subjects performed an incremental cycle ergometer test. Blood ammonia, blood lactate

  1. Hydroaminomethylation in supercritical ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Martin, A.; Kant, M. [Leibniz-Institute for Catalysis, Berlin (Germany); Klein, H.; Jackstell, R.; Beller, M. [Leibniz-Institute for Catalysis, Rostock (Germany)

    2006-07-01

    Thermodynamic measurements were carried in the reaction system of hydroaminomethylation of olefins. Mixtures of ammonia, olefins, co-solvents, syngas and products such as nonylamine used as model and water were studied. In dependence on the reaction conditions and the mixtures selected opalescence points in a region from 92-290 bar and 120-172 C were found. (orig.)

  2. Phylogenetic and functional marker genes to study ammonia-oxidizing microorganisms (AOM) in the environment.

    Science.gov (United States)

    Junier, Pilar; Molina, Verónica; Dorador, Cristina; Hadas, Ora; Kim, Ok-Sun; Junier, Thomas; Witzel, Jean-Paul; Imhoff, Johannes F

    2010-01-01

    The oxidation of ammonia plays a significant role in the transformation of fixed nitrogen in the global nitrogen cycle. Autotrophic ammonia oxidation is known in three groups of microorganisms. Aerobic ammonia-oxidizing bacteria and archaea convert ammonia into nitrite during nitrification. Anaerobic ammonia-oxidizing bacteria (anammox) oxidize ammonia using nitrite as electron acceptor and producing atmospheric dinitrogen. The isolation and cultivation of all three groups in the laboratory are quite problematic due to their slow growth rates, poor growth yields, unpredictable lag phases, and sensitivity to certain organic compounds. Culture-independent approaches have contributed importantly to our understanding of the diversity and distribution of these microorganisms in the environment. In this review, we present an overview of approaches that have been used for the molecular study of ammonia oxidizers and discuss their application in different environments.

  3. Evaluation of F1 calves sired by Brahman, Boran, and Tuli bulls for birth, growth, size, and carcass characteristics.

    Science.gov (United States)

    Herring, A D; Sanders, J O; Knutson, R E; Lunt, D K

    1996-05-01

    Birth (n = 308), weaning (n = 291), feedlot and carcass (n = 142), and yearling heifer traits (n = 139) were evaluated in F1 calves sired by Brahman (BR), Boran (BO), and Tuli (TU) bulls and born to multiparous Hereford and Angus cows. Calves sired by BR were heaviest (P Brahman crosses had larger (P Brahman F1 heifers had larger (P carcass quality traits, but not for carcass yield traits, among these three breeds.

  4. Combustion driven ammonia generation strategies for passive ammonia SCR system

    Energy Technology Data Exchange (ETDEWEB)

    Toner, Joel G.; Narayanaswamy, Kushal; Szekely, Jr., Gerald A.; Najt, Paul M.

    2016-12-06

    A method for controlling ammonia generation in an exhaust gas feedstream output from an internal combustion engine equipped with an exhaust aftertreatment system including a first aftertreatment device includes executing an ammonia generation cycle to generate ammonia on the first aftertreatment device. A desired air-fuel ratio output from the engine and entering the exhaust aftertreatment system conducive for generating ammonia on the first aftertreatment device is determined. Operation of a selected combination of a plurality of cylinders of the engine is selectively altered to achieve the desired air-fuel ratio entering the exhaust aftertreatment system.

  5. Ammonia emissions from seabird colonies

    Science.gov (United States)

    Blackall, Trevor D.; Wilson, Linda J.; Theobald, Mark R.; Milford, Celia; Nemitz, Eiko; Bull, Jennifer; Bacon, Philip J.; Hamer, Keith C.; Wanless, Sarah; Sutton, Mark A.

    2007-05-01

    Ammonia emissions were measured from two entire seabird colonies with contrasting species assemblages, to ascertain the ammonia volatilisation potentials among seabird species in relation to their nesting behaviour. Emissions were calculated from downwind plume measurements of ammonia concentration using both inverse dispersion and tracer ratio methods. Measured colony emissions ranged 1-90 kg NH3 hour-1, and equated to 16 and 36% volatilization of excreted nitrogen for colonies dominated by ground/burrow nesting and bare rock nesting birds, respectively. The results were applied in a bioenergetics model with a global seabird database. Seabird colonies are found to represent the largest point sources of ammonia globally (up to ~6 Gg NH3 colony-1 year-1). Moreover the largest emissions occur mainly in remote environments with otherwise low NH3 emissions. These ammonia ``hot spots'' explain significant perturbations of the nitrogen cycle in these regions and add ~20% to oceanic ammonia emissions south of latitude 45°S.

  6. Quantifying the thermodynamic interactions of polyhedral boranes in solution to guide nanocomposite fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Mutz, M. [University of Tennessee, Department of Chemistry (United States); Eastwood, Eric [Honeywell Kansas City Plant (United States); Lee, Mark E. [University of Missouri (United States); Bowen, Daniel E. [Honeywell Kansas City Plant (United States); Dadmun, M. D., E-mail: dad@utk.edu [University of Tennessee, Department of Chemistry (United States)

    2012-11-15

    The solubility of boron containing nanoparticles in a variety of solvents is quantified using static light scattering in conjunction with refractometry. Four polyhedral boranes were tested in this work, using refractometry to obtain dn/dc, while static light scattering quantifies A{sub 2}. A{sub 2} obtained from these measurements was then used to calculate {chi}, the solute-solvent interaction parameter, and the Hildebrand solubility parameter, {delta}, which provides a quantifiable method to identify good solvents. Of the nanoparticles studied, 1,3-di-o-carboranylpropane is thermodynamically stable in toluene, with a {chi} less than 0.5, a solubility limit of 2.47 mg/mL, and all solutions remaining clear with no visible particle settling. For all of the particles tested, there was good correlation between the physical observations of the solutions, {chi}, and {delta}. For instance, lower values of {chi} correspond to a smaller radius of gyration (R{sub g}). A list of suitable solvents based on {delta} is also presented.

  7. Quantifying the thermodynamic interactions of polyhedral boranes in solution to guide nanocomposite fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Mutz, M [The University of Tennessee; Eastwood, Eric Allen [ORNL; LeeJr, Mark E [University of Missouri; BowenIII, Daniel E [Honeywell, Inc.; Dadmun, Mark D [ORNL

    2012-01-01

    The solubility of boron containing nanoparticles in a variety of solvents is quantified using static light scattering in conjunction with refractometry. Four polyhedral boranes were tested in this work, using refractometry to obtain dn/dc, while static light scattering quantifies A2. A2 obtained from these measurements was then used to calculate v, the solute solvent interaction parameter, and the ildebrand solubility parameter, d, which provides a quantifiable method to identify good solvents. Of the nanoparticles studied, 1,3-di-o-carboranylpropane is thermodynamically stable in toluene, with a v less than 0.5, a solubility limit of 2.47 mg/mL, and all solutions remaining clear with no visible particle settling. For all of the particles tested, there was good correlation between the physical observations of the solutions, v, and d. For instance, lower values of v correspond to a smaller radius of gyration (Rg). A list of suitable solvents based on d is also presented.

  8. Tritylamine as an Ammonia Surrogate in the Ugi Tetrazole Synthesis

    NARCIS (Netherlands)

    Zhao, Ting; Boltjes, Andre; Herdtweck, Eberhardt; Doemling, Alexander

    2013-01-01

    The role of tritylamine is introduced as a convenient ammonia substitute in the Ugi tetrazole synthesis. Fifteen examples and their mild cleavage products are described In satisfactory to good yields. N-Unsubstituted alpha-aminotetrazoles are important compounds with annotated biological activities,

  9. Chemistry of peroxide compounds

    Science.gov (United States)

    Volnov, I. I.

    1981-01-01

    The history of Soviet research from 1866 to 1967 on peroxide compounds is reviewed. This research dealt mainly with peroxide kinetics, reactivity and characteristics, peroxide production processes, and more recently with superoxides and ozonides and emphasis on the higher oxides of group 1 and 2 elements. Solid state fluidized bed synthesis and production of high purity products based on the relative solubilities of the initial, intermediate, and final compounds and elements in liquid ammonia are discussed.

  10. A rationally designed amino-borane complex in a metal organic framework: A novel reusable hydrogen storage and size-selective reduction material

    KAUST Repository

    Wang, Xinbo

    2015-01-01

    A novel amino-borane complex inside a stable metal organic framework was synthesized for the first time. It releases hydrogen at a temperature of 78 °C with no volatile contaminants and can be well reused. Its application as a size-selective reduction material in organic synthesis was also demonstrated. © The Royal Society of Chemistry 2015.

  11. Synthesis and Reactivity of Novel Boranes Derived from Bulky Salicylaldimines: The Molecular Structure of a Maltolato Compound

    Directory of Open Access Journals (Sweden)

    Jeremy L. Bourque

    2015-02-01

    Full Text Available Reductive amination of salicylaldehyde or 3,5-di-tert-butylsalicylaldehyde and 1-adamantylamine using NaBH4 gave the corresponding aminoalcohols in high yields. Subsequent addition of one equivalent of H3B·SMe2 to the aminoalcohols, with loss of two equivalents of dihydrogen, resulted in the formation of adamantanyl oxazaborinanes (1a,b. The molecular structure of 1b was studied by a single crystal X-ray diffraction study. Crystals were obtained from a saturated Et2O solution and belong to the triclinic space group Pī with unit cell parameters a = 9.1267(4 Å; b = 11.676(2 Å; c = 12.240(3 Å; α = 66.840(3°; β = 78.529(3°; and γ = 67.354(3°. The molecular structure of the addition product (2a arising from maltol and 1a was also confirmed by single crystal X-ray diffraction. Crystals were obtained from a saturated 1:2 mixture of toluene/Et2O and belong to the orthorhombic space group Pna2(1 with unit cell parameters a = 18.519(6 Å; b = 17.315(5 Å; and c = 12.680(4 Å. The asymmetric unit contains two molecules that differ slightly in some of the dihedral angles.

  12. Eficiência microbiana, fluxo de compostos nitrogenados no abomaso, amônia e pH ruminais, em bovinos recebendo dietas contendo feno de capim-tifton 85 de diferentes idades de rebrota Microbial efficiency, abomasal nitrogen compounds flow, ruminal ammonia and ruminal pH in cattle fed diets containing tifton 85 bermudagrass hays at different regrowth ages

    Directory of Open Access Journals (Sweden)

    Karina Guimarães Ribeiro

    2001-04-01

    Full Text Available Avaliaram-se a eficiência de síntese microbiana, o fluxo de compostos nitrogenados no abomaso, o balanço de compostos nitrogenados, a taxa de passagem da digesta ruminal, a concentração de amônia e o pH ruminais, em bovinos recebendo rações contendo feno de capim-tifton 85 de diferentes idades de rebrota. Utilizaram-se quatro animais zebu, com peso médio de 340 kg, fistulados no rúmen e abomaso, distribuídos em um delineamento em quadrado latino 4 x 4. Todas as rações continham 60% de volumoso e 40% de concentrado. O volumoso foi constituído de feno de capim-tifton 85 de 28, 35, 42 e 56 dias de idade e o concentrado continha fubá de milho e mistura mineral. Os microorganismos ruminais foram quantificados utilizando-se as bases purinas como indicador. O pH e N-amoniacal foram mensurados, no fluido ruminal, antes e 2; 4 e 6 horas após o fornecimento da ração. A taxa de passagem foi determinada pelo modelo unicompartimental, utilizando-se o óxido crômico como indicador. As eficiências de síntese microbiana não foram influenciadas pela idade do feno na ração, apresentando valores médios de 31,32 g Nbact/kg MODR; 30,74 g Nbact/kg CHODR; 337,4 g MSbact/kg CHODR; e 12,5 g PBbact/100 g NDT. Estimaram-se máximos fluxos de compostos nitrogenados totais, amoniacais e não-amoniacais, de 119,0; 9,76; e 109,6 g/dia, com a inclusão de feno com 39,7; 37,6; e 39,9 dias de idade, respectivamente, e fluxo de compostos nitrogenados bacterianos de 80,54 g/dia, em média. O balanço de nitrogênio, a taxa de passagem, as concentrações de amônia e o pH ruminais também não foram influenciados pela idade do feno na ração, encontrando-se valores de 30,67 g/dia; 3,2%/h; 9,7 mg/100mL (máximo às 1,38h e 6,08 (mínimo às 6,64h, respectivamente.The microbial efficiency synthesis, the abomasum nitrogen compounds flow, the nitrogen compounds balance, the passage rate of ruminal digest, the ruminal ammonia concentration and ruminal pH in

  13. Mechanism of Solid-State Thermolysis of Ammonia Boraine: 15N NMR Study Using Fast Magic-Angle Spinning and Dynamic Nuclear Polarization

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Takeshi [Ames Laboratory; Gupta, Shalabh [Ames Laboratory; Caporini, Marc A [Bruker BioSpin Corporation; Pecharsky, Vitalij K [Ames Laboratory; Pruski, Marek [Ames Laboratory

    2014-08-28

    The solid-state thermolysis of ammonia borane (NH3BH3, AB) was explored using state-of-the-art 15N solid-state NMR spectroscopy, including 2D indirectly detected 1H{15N} heteronuclear correlation and dynamic nuclear polarization (DNP)-enhanced 15N{1H} cross-polarization experiments as well as 11B NMR. The complementary use of 15N and 11B NMR experiments, supported by density functional theory calculations of the chemical shift tensors, provided insights into the dehydrogenation mechanism of AB—insights that have not been available by 11B NMR alone. Specifically, highly branched polyaminoborane derivatives were shown to form from AB via oligomerization in the “head-to-tail” manner, which then transform directly into hexagonal boron nitride analog through the dehydrocyclization reaction, bypassing the formation of polyiminoborane.

  14. Global Seabird Ammonia Emissions

    Science.gov (United States)

    Riddick, S. N.; Blackall, T. D.; Dragosits, U.; Daunt, F. H.; Braban, C. F.; Tang, Y. S.; Trathan, P.; Wanless, S.; Sutton, M. A.

    2010-12-01

    Seabird colonies represent a major source of atmospheric ammonia (NH3) in remote coastal and marine systems in temperate, tropical and polar regions. Previous studies have shown that NH3 emissions from Scottish seabird colonies were substantial - of similar magnitude to the most intensive agricultural point source emissions. The UK data were used to model global seabird NH3 emissions and suggested that penguins are a major source of emissions on and around the Antarctic continent. The largest seabird colonies are in the order of millions of seabirds. Due to the isolation of these colonies from anthropogenic nitrogen sources, they may play a major role in the nitrogen cycle within these ecosystems. A global seabird database was constructed and used in conjunction with a species-specific seabird bioenergetics model to map the locations of NH3 emissions from seabird colonies. The accuracy of the modelled emissions was validated with field data of NH3 emissions measured at key seabird colonies in different climatic regions of the world: temperate (Isle of May, Scotland), tropical (Ascension Island) and polar (Signy Island, South Georgia). The field data indicated good agreement between modelled and measured NH3 emissions. The measured NH3 emissions also showed the variability of emission with climate. Climate dependence of seabird NH3 emissions may have further implications under a changing global climate. Seabird colonies represent NH3 emission ‘hotspots’, often far from anthropogenic sources, and are likely to be the major source of nitrogen input to these remote coastal ecosystems. The direct manuring by seabirds at colony locations may strongly influence species richness and biodiversity. The subsequent volatilisation and deposition of NH3 increases the spatial extent of seabird influence on nitrogen cycling in their local ecosystem. As many seabird populations are fluctuating due to changing food supply, climate change or anthropogenic pressures, these factors

  15. MEASUREMENT OF AMMONIA RELEASE FROM SALTSTONE

    Energy Technology Data Exchange (ETDEWEB)

    Zamecnik, J; Alex Cozzi, A

    2009-01-15

    SRNL was requested by WSRC Waste Solidification Engineering to characterize the release of ammonia from saltstone curing at 95 C by performing experimental testing. These tests were performed with an MCU-type Tank 50H salt simulant containing 0, 50, and 200 mg/L ammonia. The testing program showed that above saltstone made from the 200 mg/L ammonia simulant, the vapor space ammonia concentration was about 2.7 mg/L vapor at 95 C. An upper 95% confidence value for this concentration was found to be 3.9 mg/L. Testing also showed that ammonia was chemically generated from curing saltstone at 95 C; the amount of ammonia generated was estimated to be equivalent to 121 mg/L additional ammonia in the salt solution feed. Even with chemical generation, the ammonia release from saltstone was found to be lower than its release from salt solution only with 200 mg/L ammonia.

  16. Fast and accurate exhaled breath ammonia measurement.

    Science.gov (United States)

    Solga, Steven F; Mudalel, Matthew L; Spacek, Lisa A; Risby, Terence H

    2014-06-11

    This exhaled breath ammonia method uses a fast and highly sensitive spectroscopic method known as quartz enhanced photoacoustic spectroscopy (QEPAS) that uses a quantum cascade based laser. The monitor is coupled to a sampler that measures mouth pressure and carbon dioxide. The system is temperature controlled and specifically designed to address the reactivity of this compound. The sampler provides immediate feedback to the subject and the technician on the quality of the breath effort. Together with the quick response time of the monitor, this system is capable of accurately measuring exhaled breath ammonia representative of deep lung systemic levels. Because the system is easy to use and produces real time results, it has enabled experiments to identify factors that influence measurements. For example, mouth rinse and oral pH reproducibly and significantly affect results and therefore must be controlled. Temperature and mode of breathing are other examples. As our understanding of these factors evolves, error is reduced, and clinical studies become more meaningful. This system is very reliable and individual measurements are inexpensive. The sampler is relatively inexpensive and quite portable, but the monitor is neither. This limits options for some clinical studies and provides rational for future innovations.

  17. Birth and weaning traits in crossbred cattle from Hereford, Angus, Brahman, Boran, Tuli, and Belgian Blue sires.

    Science.gov (United States)

    Casas, E; Thallman, R M; Cundiff, L V

    2011-04-01

    The objective of this study was to characterize breeds representing diverse biological types for birth and weaning traits in crossbred cattle. Gestation length, calving difficulty, percentage of unassisted calving, percentage of perinatal survival, percentage of survival from birth to weaning, birth weight, BW at 200 d, and ADG were measured in 2,500 calves born and 2,395 calves weaned. Calves were obtained by mating Hereford, Angus, and MARC III (one-fourth Hereford, one-fourth Angus, one-fourth Pinzgauer, and one-fourth Red Poll) mature cows to Hereford or Angus (British breed), Brahman, Tuli, Boran, and Belgian Blue sires. Calves were born during the spring seasons of 1992, 1993, and 1994. Sire breed was significant for all traits (P gestation length (285 d) when compared with progeny from other sire breeds (average of 291 d). Calving difficulty was greater in offspring from Brahman sires (1.24), whereas the offspring of Tuli sires had the least amount of calving difficulty (1.00). Offspring from all sire breeds had similar perinatal survival and survival from birth to weaning (average of 97.2 and 96.2%, respectively), with the exception of offspring from Brahman sires, which had less (92.8 and 90.4%, respectively). Progeny of Brahman sires were heaviest at birth (45.7 kg), followed by offspring from British breed, Boran, and Belgian Blue sires (average of 42.4 kg). The lightest offspring at birth were from Tuli sires (38.6 kg). Progeny derived from Brahman sires were the heaviest at 200 d (246 kg), and they grew faster (1.00 kg/d) than offspring from any other group. The progeny of British breeds and the Belgian Blue breed had an intermediate BW at 200 d (238 kg) and an intermediate ADG (average of 0.98 kg/d). The progeny of Boran and Tuli sires were the lightest at 200 d (227 kg) and had the least ADG (0.93 kg/d). Male calves had a longer gestation length, had a greater incidence of calving difficulty, had greater mortality to weaning, were heavier, and grew

  18. Effect of the phosphine steric and electronic profile on the Rh-promoted dehydrocoupling of phosphine-boranes.

    Science.gov (United States)

    Hooper, Thomas N; Huertos, Miguel A; Jurca, Titel; Pike, Sebastian D; Weller, Andrew S; Manners, Ian

    2014-04-07

    The electronic and steric effects in the stoichiometric dehydrocoupling of secondary and primary phosphine-boranes H3B·PR2H [R = 3,5-(CF3)2C6H3; p-(CF3)C6H4; p-(OMe)C6H4; adamantyl, Ad] and H3B·PCyH2 to form the metal-bound linear diboraphosphines H3B·PR2BH2·PR2H and H3B·PRHBH2·PRH2, respectively, are reported. Reaction of [Rh(L)(η(6)-FC6H5)][BAr(F)4] [L = Ph2P(CH2)3PPh2, Ar(F) = 3,5-(CF3)2C6H3] with 2 equiv of H3B·PR2H affords [Rh(L)(H)(σ,η-PR2BH3)(η(1)-H3B·PR2H)][BAr(F)4]. These complexes undergo dehydrocoupling to give the diboraphosphine complexes [Rh(L)(H)(σ,η(2)-PR2·BH2PR2·BH3)][BAr(F)4]. With electron-withdrawing groups on the phosphine-borane there is the parallel formation of the products of B-P cleavage, [Rh(L)(PR2H)2][BAr(F)4], while with electron-donating groups no parallel product is formed. For the bulky, electron rich, H3B·P(Ad)2H no dehydrocoupling is observed, but an intermediate Rh(I) σ phosphine-borane complex is formed, [Rh(L){η(2)-H3B·P(Ad)2H}][BAr(F)4], that undergoes B-P bond cleavage to give [Rh(L){η(1)-H3B·P(Ad)2H}{P(Ad)2H}][BAr(F)4]. The relative rates of dehydrocoupling of H3B·PR2H (R = aryl) show that increasingly electron-withdrawing substituents result in faster dehydrocoupling, but also suffer from the formation of the parallel product resulting from P-B bond cleavage. H3B·PCyH2 undergoes a similar dehydrocoupling process, and gives a mixture of stereoisomers of the resulting metal-bound diboraphosphine that arise from activation of the prochiral P-H bonds, with one stereoisomer favored. This diastereomeric mixture may also be biased by use of a chiral phosphine ligand. The selectivity and efficiencies of resulting catalytic dehydrocoupling processes are also briefly discussed.

  19. Reducing concentrations of ammonia to nontoxic levels prior to initiating whole-sediment bioassays

    Energy Technology Data Exchange (ETDEWEB)

    Barrows, E.S.; Pinza, M.R.; Word, J.O. [Battelle/Marine Sciences Lab., Sequim, WA (United States); Greges, M.

    1994-12-31

    Determining the suitability of dredged material for ocean disposal requires whole-sediment toxicity tests with marine organisms. In addition to potential contaminants in dredged sediment, factors including grain size, salinity, hydrogen sulfide and ammonia can contribute to observed toxicity, thereby confounding test results. The presence of ammonia, a non-persistent but toxic compound, is particularly interesting because in open-water dredge and disposal situations, ammonia may not be a contaminant of concern. Sediment porewater ammonia concentrations in bioassays can be reduced to nontoxic levels before exposing organisms to permit evaluation of sediment contaminants without the additional toxicity effects of ammonia. Ten-day acute toxicity tests were conducted on sediments with Ampelisca abdita, Rhepoxynius abronius, Eohaustorius estuarius, and Mysidopsis bahia. Two procedures were followed to reduce ammonia prior to test initiation. In one, sediments in test chambers stood for 7 to 1 2 days while natural, nitrogen-reducing processes took place. In the other, sediments were tested in modified, flow-through systems. Ammonia was monitored in sediment porewater during ``purging`` periods, at test initiation and termination, and in overlying water during testing. Results were compared to the measured dose response of each species to ammonia, as determined by water-only reference toxicant tests. The question remains whether other sediment characteristics are affected by these procedures.

  20. Oxygen Distribution and Potential Ammonia Oxidation in Floating, Liquid Manure Crusts

    DEFF Research Database (Denmark)

    Nielsen, Daniel Aagren; Nielsen, Lars Peter; Schramm, Andreas;

    2010-01-01

    Floating, organic crusts on liquid manure, stored as a result of animal production, reduce emission of ammonia (NH3) and other volatile compounds during storage. The occurrence of NO2- and NO3- in the crusts indicate the presence of actively metabolizing NH3 oxidizing bacteria (AOB) which may...... microorganisms, including AOB. The microbial activity may thus contribute to a considerable reduction of ammonia emissions from slurry tanks with well-developed crusts....

  1. [Ammonia, glutamine and glutamic acid content of rat tissues during and after hyperoxia].

    Science.gov (United States)

    Gabibov, M M

    1975-01-01

    The content of ammonia, glutamine, glutamic acid was measured in the brain, liver, heart, spleen, kidneys, skeletal muscles and blood rats exposed to a 4 atm oxygen atmosphere and during aftereffects. The hyperoxic atmosphere resulted in an increase of ammonia and glutamic acid and in a decrease of glutamine in the tissues. The return to the norm of the compounds occurred slowly and nonuniformly, lasting for 40 to 60 posthyperoxic days.

  2. Degradation of spent craft brewer’s yeast by caprine rumen hyper ammonia-producing bacteria

    Science.gov (United States)

    Spent brewer’s yeast has long been included in ruminant diets as a protein supplement. However, modern craft beers often include more hops (Humulus lupulus L.) compounds than traditional recipes. These compounds include alpha and beta-acids, which are antimicrobial to the rumen hyper ammonia-produci...

  3. Ammonia synthesis at low temperatures

    DEFF Research Database (Denmark)

    Rod, Thomas Holm; Logadottir, Ashildur; Nørskov, Jens Kehlet

    2000-01-01

    Density functional theory (DFT) calculations of reaction paths and energies for the industrial and the biological catalytic ammonia synthesis processes are compared. The industrial catalyst is modeled by a ruthenium surface, while the active part of the enzyme is modeled by a MoFe6S9 complex...... have been carried out to evaluate its feasibility. The calculations suggest that it might be possible to catalytically produce ammonia from molecular nitrogen at low temperatures and pressures, in particular if energy is fed into the process electrochemically. (C) 2000 American Institute of Physics....

  4. Dihydrogen activation by frustrated carbene-borane Lewis pairs: an experimental and theoretical study of carbene variation.

    Science.gov (United States)

    Kronig, Sabrina; Theuergarten, Eileen; Holschumacher, Dirk; Bannenberg, Thomas; Daniliuc, Constantin G; Jones, Peter G; Tamm, Matthias

    2011-08-01

    A variety of Lewis acid-base pairs consisting of tris(pentafluorophenyl)borane, B(C(6)F(5))(3), in combination with sterically demanding five- and six-membered N-heterocyclic carbenes (NHCs) of the imidazolin-2-ylidene, imidazolidin-2-ylidene, and tetrahydropyrimidin-2-ylidene types were investigated with respect to their potential to act as frustrated Lewis pairs (FLP) by reaction with dihydrogen (H(2)) and tetrahydrofuran (THF). A sufficient degree of "frustration" was usually established by introduction of a 1,3-di-tert-butyl or 1,3-diadamantyl carbene substitution pattern, which allows an unquenched acid-base reactivity and thus leads to heterolytic dihydrogen activation and ring-opening of THF. In contrast, 1,3-bis(2,6-diisopropylphenyl)-substituted carbenes showed ambiguous behavior, and the corresponding five-membered imidazolin-2-ylidene formed a stable carbene-B(C(6)F(5))(3) adduct, whereas fast C-F activation and formation of a zwitterionic pyrimidinium-fluoroborate was observed for the six-membered tetrahydropyrimidin-2-ylidene. A stable adduct was also isolated for the combination of the acyclic carbene bis(diisopropylamino)methylene with B(C(6)F(5))(3), and consequently no reactivity toward H(2) and THF was observed. To rationalize the reactivity of the carbene-borane Lewis pairs, the thermodynamics of adduct formation with B(C(6)F(5))(3) were calculated for 10 different carbenes; the stability (or instability) of these adducts can be used as a good measure of the degree of "frustration".

  5. Nitrocarburizing in ammonia-hydrocarbon gas mixtures

    DEFF Research Database (Denmark)

    Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

    2011-01-01

    The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammonia-propene-hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere...

  6. Enrichment of high ammonia tolerant methanogenic culture

    DEFF Research Database (Denmark)

    Fotidis, Ioannis; Karakashev, Dimitar Borisov; Proietti, Nicolas

    Ammonia is the major toxicant in full scale anaerobic digesters of animal wastes which are rich in proteins and/or urea, such as pig or poultry wastes. Ammonia inhibition decreases methane production rates, increases volatile fatty acids concentration and leads to economic losses for the biogas...... plants. The methods used today to counteract ammonia inhibition are slow and costexpensive. A new biological approach to avoid or counteract ammonia inhibition by using ammonia tolerant methanogens, could provide a sustainable solution for cost-effective digestion of abundant ammonia-rich wastes. The aim...... of the current study was to isolate and identify methanogenic cultures tolerant to high ammonia concentrations. A mixed methanogenic population was stepwise exposed to ammonia concentrations (1 to 9.26 g NH4+-N L-1) during an enrichment process with successive batch cultivations. The methanogenic population...

  7. RESULTS OF INITIAL AMMONIA OXIDATION TESTING

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-12-30

    This memo presents an experimental survey of aqueous phase chemical processes to remove aqueous ammonia from waste process streams. Ammonia is generated in both the current Hanford waste flowsheet and in future waste processing. Much ammonia will be generated in the Low Activity Waste (LAW) melters.i Testing with simulants in glass melters at Catholic University has demonstrated the significant ammonia production.ii The primary reaction there is the reducing action of sugar on nitrate in the melter cold cap. Ammonia has been found to be a problem in secondary waste stabilization. Ammonia vapors are noxious and destruction of ammonia could reduce hazards to waste treatment process personnel. It is easily evolved especially when ammonia-bearing solutions are adjusted to high pH.

  8. Selective reversible hydrogenation of Mg(B3H8)2/MgH2 to Mg(BH4)2: pathway to reversible borane-based hydrogen storage?

    Science.gov (United States)

    Chong, Marina; Matsuo, Motoaki; Orimo, Shin-ichi; Autrey, Tom; Jensen, Craig M

    2015-04-20

    Mg(B3H8)2·2THF (THF = tetrahydrofuran) was prepared by the addition of BH3·THF to Mg/Hg amalgam. Heating a 1:2 molar mixture of Mg(B3H8)2·2THF and MgH2 to 200 °C under 5 MPa H2 for 2 h leads to nearly quantitative conversion to Mg(BH4)2. The differential scanning calorimetry profile of the reaction measured under 5 MPa H2 shows an initial endothermic feature at ∼65 °C for a phase change of the compound followed by a broad exothermic feature that reaches a maximum at 130 °C corresponding to the hydrogenation of Mg(B3H8)2 to Mg(BH4)2. Heating Mg(B3H8)2·2THF to 200 °C under 5 MPa H2 pressure in the absence of MgH2 gives predominantly MgB12H12 as well as significant amounts of MgB10H10 and Mg(BH4)2. Hydrogenation of a mixture of Mg(B3H8)2·2THF and LiH in a 1:4 molar ratio at 130 °C under 5 MPa H2 yields [B12H12](2-) in addition to [BH4](-), while a 1:4 molar ratio of Mg(B3H8)2·2THF and NaH yields [BH4](-) and a new borane, likely [B2H7](-). Hydrogenation of the NaH-containing mixture at 130 °C gives primarily the alternative borane, indicating it is an intermediate in the two-step conversion of the triborane to [BH4](-). The solvent-free triborane Mg(B3H8)2, derived from the low-temperature dehydrogenation of Mg(BH4)2, also produces Mg(BH4)2, but higher temperature and pressure is required to effect the complete transformation of the Mg(B3H8)2. These results show that the reversible transformation of the triborane depends on the stability of the metal hydride. The more stable the metal hydride, that is, LiH > NaH > MgH2, the lower is the "regeneration" efficiency.

  9. Emissions, sinks and gas to particle conversion of amines and ammonia

    Science.gov (United States)

    Lee, S.

    2015-12-01

    Nitrogen-containing base compounds, amines and ammonia, play important roles in formation of secondary aerosols in the atmosphere, but their sources, sinks and atmospheric transformation processes are not well understood. Also, there are very limited analytical methods that are capable of measuring pptv or sub-pptv level of amines and ammonia. We have developed a chemical ionization mass spectrometer (CIMS) that can detect amines and ammonia at the pptv and sub-pptv level with a 1 min of integration time. Here, we report ambient measurements of amines and ammonia made in a moderately polluted continental site (Kent, Ohio) and in a rural Southeastern U.S. forest (Centreville, Alabama). Our finding indicate that there are much more abundant gas phase amines (C1-C6) and ammonia in the polluted site than in the rural forest, highlighting the importance of constraining anthropogenic emission sources of amines. At both locations, concentrations of these base compounds show clear temperature dependence, indicating strong gas-to-particle conversion processes. Compared to ammonia, amines can partition into aerosol phases even more effectively due to lower saturation vapor pressures. Measurements in the clean rural forest show that transported biomass burning plumes are the major source of amines. These nitrogen-containing compounds effectively undergo wet deposition in the atmosphere due to high solubilities.

  10. DETERMINATION OF AMMONIA IN EAR-LOBE CAPILLARY BLOOD IS AN ALTERNATIVE TO ARTERIAL BLOOD AMMONIA

    NARCIS (Netherlands)

    HUIZENGA, [No Value; GIPS, CH; CONN, HO; JANSEN, PLM

    1995-01-01

    Blood ammonia determination is a laboratory test to diagnose hepatic encephalopathy. Arterial blood is superior to peripheral venous blood ammonia because of ammonia metabolism in muscle. We have compared capillary with arterial whole blood ammonia as capillary sampling is an attractive alternative.

  11. 46 CFR 154.1760 - Liquid ammonia.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Liquid ammonia. 154.1760 Section 154.1760 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR....1760 Liquid ammonia. The master shall ensure that no person sprays liquid ammonia into a cargo...

  12. 27 CFR 21.96 - Ammonia, aqueous.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Ammonia, aqueous. 21.96 Section 21.96 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT... Ammonia, aqueous. (a) Alkalinity. Strongly alkaline to litmus. (b) Ammonia content. 27 to 30 percent...

  13. Parameter Optimization on Experimental Study to Reduce Ammonia Escape in CO2 Absorption by Ammonia Scrubbing

    Institute of Scientific and Technical Information of China (English)

    Hao Leng; Jianmin Gao; Mingyue He; Min Xie; Qian Du; Rui Sun; Shaohua Wu

    2016-01-01

    In order to research ammonia escape in CO2 absorption by ammonia scrubbing, ammonia escape was studied in CO2 absorption process using the bubbling reactor in different conditions as gas flow rate, CO2 ratio, absorbent temperature and ammonia concentration and quantity of escaped ammonia was measured by chemical titration. The results indicated that, the amount of ammonia escape can be around 20% of original amount in 90 min and the escaped amount will increase with the rise of gas flow rate, absorbent temperature, concentration of ammonia while decrease as CO2 ratio goes up. Through the analysis of the law of ammonia escape, at the same time, combined with ammonia escape and the influence of the relationship between the CO2 absorption efficiency, reducing ammonia escape working condition parameter optimization is given.

  14. Ammonia in power plant emission

    Science.gov (United States)

    Hammerich, Mads; Henningsen, J. O.; Olafsson, Ari

    1990-08-01

    Ammonia monitoring is needed in most schemes for denitrification of power plant emission. In the PALAMON system we use a 500 MHz tunable, single mode, single line, CO2 laser as light source for a low pressure, high temperature, photoacoustic cell. With this cell we can resolve the sR(5,O) line of the ammonia spectrum, and suppress the interfering C02(9R30) absorption line down to a lppm NH3 detection limit. The validity of the measured ammonia concentrations is strongly dependent on details of the sampling system and on the reliability of the calibration routines. In particular calibration with certified mixtures of NH3:N2 has proved insufficient due to the multiple and long time constants caused by adsorption of ammonia to different materials in the system. Presence of water vapor in the gas greatly reduces these time constants. Therefore a number of methods for simple production of moist calibration gases from macroscopic amounts of NH3 are applied. The calibrations are translated to response from an easily managable absorber in order to allow automated recalibration of the photoacoustic response. Data from a field test of the system, and calibration data will be presented.

  15. Ceramic Membranes for Ammonia Recovery

    Energy Technology Data Exchange (ETDEWEB)

    Camus, O.; Perera, S.; Crittenden, B. [Department of Chemical Engineering, University of Bath, Bath, BA2 7AY (United Kingdom); Van Delft, Y.C.; Meyer, D.F.; Pex, P.P.A.C. [ECN Solar Energy, Westerduinweg 3, P.O. Box 1, 1755 ZG Petten (Netherlands); Kumakiri, I.; Miachon, S.; Dalmon, J.A. [CNRS-Institut de Recherches sur la Catalyse 2, av. A. Einstein, 69626 Villeurbanne (France); Tennison, S. [MAST Carbon, Ltd., Henley Park, Guildford, Surrey, GU3 2AF (United Kingdom); Chanaud, P. [Pall-Exekia, BP1, Usine a Bazet (France); Groensmit, E. [Kemira GrowHow SA/NV, Avenue Einstein 11, B-1300 Wavre (Belgium); Nobel, W. [Continental Engineers BV, Rustenburg 114, 1506 AZ Zaandam (Netherlands)

    2008-12-15

    An extensive screening program has been performed to find a suitable membrane configuration and operating conditions for the effective recovery of ammonia from the syngas loop. All the experiments have been performed at steady state. MFI zeolite membranes in tubular and multi-channel fiber configurations have been tested along with tubular silica membranes. At 80C, a high ammonia permeance (2.1 x 10{sup -7} mol.m{sup -2}.s{sup -1}.Pa{sup -1}), and a selectivity of about 10 were found with the tubular zeolite membrane, whereas for the silica membrane an even higher ammonia permeance was measured (7.6 x 10{sup -7} mol.m{sup -2}.s{sup -1}.Pa{sup -1}) with a selectivity of about 7. For both silica and zeolite membranes, the selectivity was found to increase with increasing temperature up to 80C. This is a combined effect of weaker adsorption of ammonia and increased diffusion at higher temperature. The results have been modeled using both the well-mixed reactor and the log mean pressure difference approaches. To overcome their limitations in addressing changes in feed concentration along the membrane surface, a segmental model has been used to obtain suitable operating conditions and membrane areas required for an industrial application.

  16. Inhibiting Wet Oxidation of Ammonia

    Science.gov (United States)

    Onisko, D. B. L.

    1985-01-01

    Simple modification of wet-oxidation process for treating organicwaste reduces loss of fixed nitrogen, potentially valuable byproduct of process. Addition of sufficient sulfuric acid to maintain reaction pH below 3 greatly reduces oxidation of ammonia to free nitrogen. No equipment modification required.

  17. Reducing ammonia emissions in Europe

    DEFF Research Database (Denmark)

    Jacobsen, Brian H.

    2011-01-01

    The NEC directive has set targets for the 2010 ammonia emissions from a number of European countries. The target will be reached by most EU-countries and the total emission for EU-27 has been reduced by 22% from 1990 to 2007. Denmark is one of the countries with the largest reductions since 1990...

  18. Forthcoming Oversupply for Synthetic Ammonia

    Institute of Scientific and Technical Information of China (English)

    Zhang Zhantong

    2007-01-01

    @@ Stable output increase The total capacity of synthetic ammonia in China is 52.0 million t/a today.There are around 540 producers mainly located in Shandong, Shanxi, Hebei,Henan, Jiangsu and Sichuan provinces.The cumulative capacity in Shandong province ranks the highest, accounting for 14.6% of the national total.

  19. Transcriptional Response of the Archaeal Ammonia Oxidizer Nitrosopumilus maritimus to Low and Environmentally Relevant Ammonia Concentrations

    OpenAIRE

    Nakagawa, Tatsunori; Stahl, David A.

    2013-01-01

    The ability of chemoautotrophic ammonia-oxidizing archaea to compete for ammonia among marine microorganisms at low ambient concentrations has been in part attributed to their extremely high affinity for ammonia, but as yet there is no mechanistic understanding of supporting metabolism. We examined transcription of selected genes for anabolic functions (CO2 fixation, ammonia transport, and cell wall synthesis) and a central catabolic function (ammonia oxidation) in the thaumarchaeon Nitrosopu...

  20. Transcriptional response of the archaeal ammonia oxidizer Nitrosopumilus maritimus to low and environmentally relevant ammonia concentrations.

    Science.gov (United States)

    Nakagawa, Tatsunori; Stahl, David A

    2013-11-01

    The ability of chemoautotrophic ammonia-oxidizing archaea to compete for ammonia among marine microorganisms at low ambient concentrations has been in part attributed to their extremely high affinity for ammonia, but as yet there is no mechanistic understanding of supporting metabolism. We examined transcription of selected genes for anabolic functions (CO2 fixation, ammonia transport, and cell wall synthesis) and a central catabolic function (ammonia oxidation) in the thaumarchaeon Nitrosopumilus maritimus SCM1 growing at two ammonia concentrations, as measured by combined ammonia and ammonium, one well above the Km for ammonia oxidation (∼500 μM) and the other well below the Km (ammonia-replete to ammonia-limiting conditions. Transcript levels for ammonia oxidation, CO2 fixation, and one of the ammonia transport genes were approximately the same at high and low ammonia availability. Transcripts for all analyzed genes decreased with time in the complete absence of ammonia, but with various rates of decay. The new steady-state mRNA levels established are presumably more reflective of the natural physiological state of ammonia-oxidizing archaea and offer a reference for interpreting message abundance patterns in the natural environment.

  1. Determination of Genetic Structure and Signatures of Selection in Three Strains of Tanzania Shorthorn Zebu, Boran and Friesian Cattle by Genome-Wide SNP Analyses

    Science.gov (United States)

    Msalya, George; Kim, Eui-Soo; Laisser, Emmanuel L. K.; Kipanyula, Maulilio J.; Karimuribo, Esron D.; Kusiluka, Lughano J. M.; Chenyambuga, Sebastian W.; Rothschild, Max F.

    2017-01-01

    Background More than 90 percent of cattle in Tanzania belong to the indigenous Tanzania Short Horn Zebu (TSZ) population which has been classified into 12 strains based on historical evidence, morphological characteristics, and geographic distribution. However, specific genetic information of each TSZ population has been lacking and has caused difficulties in designing programs such as selection, crossbreeding, breed improvement or conservation. This study was designed to evaluate the genetic structure, assess genetic relationships, and to identify signatures of selection among cattle of Tanzania with the main goal of understanding genetic relationship, variation and uniqueness among them. Methodology/Principal findings The Illumina Bos indicus SNP 80K BeadChip was used to genotype genome wide SNPs in 168 DNA samples obtained from three strains of TSZ cattle namely Maasai, Tarime and Sukuma as well as two comparative breeds; Boran and Friesian. Population structure and signatures of selection were examined using principal component analysis (PCA), admixture analysis, pairwise distances (FST), integrated haplotype score (iHS), identical by state (IBS) and runs of homozygosity (ROH). There was a low level of inbreeding (F~0.01) in the TSZ population compared to the Boran and Friesian breeds. The analyses of FST, IBS and admixture identified no considerable differentiation between TSZ trains. Importantly, common ancestry in Boran and TSZ were revealed based on admixture and IBD, implying gene flow between two populations. In addition, Friesian ancestry was found in Boran. A few common significant iHS were detected, which may reflect influence of recent selection in each breed or strain. Conclusions Population admixture and selection signatures could be applied to develop conservation plan of TSZ cattle as well as future breeding programs in East African cattle. PMID:28129396

  2. More user-friendly phosphines? Molecular structure of methylphosphine and its adduct with borane, studied by gas-phase electron diffraction and quantum chemical calculations

    OpenAIRE

    2008-01-01

    The molecular structures of methylphosphine (CH3PH2) and methylphosphine-borane (CH3PH2·BH3) have been determined from gas-phase electron diffraction data and rotational constants, employing the SARACEN method. The experimental geometric parameters generally showed a good agreement with those obtained using ab initio calculations and previous microwave spectroscopy studies. In order to assess the accuracy of the calculated structures a range of ab initio methods were used, including the CCSD(...

  3. Ammonia as efficient fuel for SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Fuerte, A.; Valenzuela, R.X.; Escudero, M.J. [CIEMAT, Departamento de Energia, Av. Complutense 22, 28040 Madrid (Spain); Daza, L. [CIEMAT, Departamento de Energia, Av. Complutense 22, 28040 Madrid (Spain); Instituto de Catalisis y Petroleoquimica (CSIC), C/Marie Curie 2, Campus Cantoblanco, 28049 Madrid (Spain)

    2009-07-01

    Ammonia is a possible candidate as the fuel for SOFCs. In this work, the influence on the performance of a tubular SOFC running on ammonia is studied. Analysis of open circuit voltages (OCVs) on the cell indicated the oxidation of ammonia within a SOFC is a two-stage process: decomposition of the inlet ammonia into nitrogen and hydrogen, followed by oxidation of hydrogen to water. For comparison, cell was also tested with hydrogen as the fuel and air as oxidant at different temperatures showing a similar behaviour. The performance of the cell tested under various conditions shows the high potential of ammonia as fuel for SOFCs. (author)

  4. Ammonia for hydrogen storage: challenges and opportunities

    DEFF Research Database (Denmark)

    Klerke, Asbjørn; Christensen, Claus H.; Nørskov, Jens Kehlet

    2008-01-01

    The possibility of using ammonia as a hydrogen carrier is discussed. Compared to other hydrogen storage materials, ammonia has the advantages of a high hydrogen density, a well-developed technology for synthesis and distribution, and easy catalytic decomposition. Compared to hydrocarbons...... and alcohols, it has the advantage that there is no CO2 emission at the end user. The drawbacks are mainly the toxicity of liquid ammonia and the problems related to trace amounts of ammonia in the hydrogen after decomposition. Storage of ammonia in metal ammine salts is discussed, and it is shown...... that this maintains the high volumetric hydrogen density while alleviating the problems of handling the ammonia. Some of the remaining challenges for research in ammonia as a hydrogen carrier are outlined....

  5. Catalytic decomposition of ammonia in a fuel gas at high temperature and pressure

    Energy Technology Data Exchange (ETDEWEB)

    Mojtahedi, W.; Abbasian, J. [Enviropower Inc., Espoo (Finland)

    1995-11-01

    In connection with the purification of fuel gas for gas turbines in the IGCC process to meet NO{sub x} standards and maintain the thermal efficiency of the process, tests were carried out with a 7.5 cm pressurized reactor to decompose ammonia at high temperature (700-900{degree}C) and pressure (2 MPa) using Ni-based catalysts. The effects of temperature, pressure, ammonia concentration and gas residence time were determined. The simulated coal gas composition was varied to allow assessment of the effect of contaminants (sulfur compounds and tars) on the ammonia decomposition efficiency of five catalysts under otherwise identical operating conditions. The results show that two of the catalysts tested are capable of efficiently reducing the concentration of ammonia in the gas. 12 refs., 13 figs.

  6. Ammonia Production, Excretion, Toxicity, and Defense in Fish: A Review

    OpenAIRE

    Yuen K Ip; Chew, Shit F.

    2010-01-01

    Many fishes are ammonotelic but some species can detoxify ammonia to glutamine or urea. Certain fish species can accumulate high levels of ammonia in the brain or defense against ammonia toxicity by enhancing the effectiveness of ammonia excretion through active NH 4 + transport, manipulation of ambient pH, or reduction in ammonia permeability through the branchial and cutaneous epithelia. Recent reports on ammonia toxicity in mammalian brain reveal the importance of permeation of ammonia thr...

  7. Ammonia Process by Pressure Swing Adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Dr Felix Jegede

    2010-12-27

    The overall objective of the project is to design, develop and demonstrate a technically feasible and commercially viable system to produce ammonia along with recovery of the products by adsorption separation methods and significantly decrease the energy requirement in ammonia production. This is achieved through a significantly more efficient ammonia psa recovery system. The new ammonia recovery system receives the reactor effluents and achieves complete ammonia recovery, (which completely eliminates the energy intensive refrigeration and condensation system currently used in ammonia production). It also recovers the unused reactants and recycles them back to the reactor, free of potential reactor contaminants, and without the need for re-compression and re-heat of recycle stream thereby further saving more energy. The result is a significantly lower energy consumption, along with capital cost savings.

  8. Ammonia emission from crop residues : quantification of ammonia volatilization based on crop residue properties

    NARCIS (Netherlands)

    Ruijter, de F.J.; Huijsmans, J.F.M.

    2012-01-01

    This paper gives an overview of available literature data on ammonia volatilization from crop residues. From these data, a relation is derived for the ammonia emission depending on the N-content of crop residue.

  9. Effect of digestion time on anaerobic digestion with high ammonia concentration

    Science.gov (United States)

    Oktavitri, Nur Indradewi; Purnobasuki, Hery; Kuncoro, Eko Prasetyo; Purnamasari, Indah; Semma Hadinnata, P.

    2016-03-01

    Anaerobic digestion was developed to treat high concentration organic compound efficiently in certain Digestion Time (DT). High ammonia concentration could influenced removal organic compound in digestion. This bench scale study investigated the effect of digestion time on anaerobic batch reactor with high ammonia concentration. Total Ammonia Nitrogen (TAN) concentration was adjusted 4000 and 5000 mg/1, Digestion time was ranged from 0-26 d, operation temperature was ranged from 28-29°C, inoculum was collected from slaughter house sludge. The degradation of Chemical Oxygen Demand (COD) correlated with digestion time. The concentration of TAN from synthetic wastewater contain 5000 mg/1 of TAN more fluctuated than those use 4000 mg/1 of TAN. However, the biogas production from wastewater contained 4000 mg/1 of TAN gradually increased until 24 d of DT. The reactor contain 5000 mg/1 of TAN only growth until 12 d and steady state at over 12 d of digestion time.

  10. Reducing ammonia emissions in Europe

    DEFF Research Database (Denmark)

    Jacobsen, Brian H.

    2011-01-01

    The NEC directive has set targets for the 2010 ammonia emissions from a number of European countries. The target will be reached by most EU-countries and the total emission for EU-27 has been reduced by 22% from 1990 to 2007. Denmark is one of the countries with the largest reductions since 1990...... to the high expectations at the outset. Despite this, the paper concludes that Denmark is likely to reduce emission by 50% from 1990 to 2020 and reach the likely 2020 NEC ceiling....

  11. Ammonia impairs glutamatergic communication in astroglial cells: protective role of resveratrol.

    Science.gov (United States)

    Bobermin, Larissa Daniele; Hansel, Gisele; Scherer, Emilene B S; Wyse, Angela T S; Souza, Diogo Onofre; Quincozes-Santos, André; Gonçalves, Carlos-Alberto

    2015-12-01

    Ammonia is a key toxin in the precipitation of hepatic encephalopathy (HE), a neuropsychiatric disorder associated with liver failure. In response to ammonia, various toxic events are triggered in astroglial cells, and alterations in brain glutamate communication are common. Resveratrol is a polyphenolic compound that has been extensively studied in pathological events because it presents several beneficial effects, including some in the central nervous system (CNS). We previously described that resveratrol is able to significantly modulate glial functioning and has a protective effect during ammonia challenge in vitro. In this study, we addressed the mechanisms by which resveratrol can protect C6 astroglial cells from glutamatergic alterations induced by ammonia. Resveratrol was able to prevent all the effects triggered by ammonia: (i) decrease in glutamate uptake activity and expression of the EAAC1 glutamate transporter, the main glutamate transporter present in C6 cells; (ii) increase of glutamate release, which was also dependent on the activation of the Na(+)-K(+)-Cl(-) co-transporter NKCC1; (iii) reduction in GS activity and intracellular GSH content; and (iv) impairment of Na(+)K(+)-ATPase activity. Interestingly, resveratrol, per se, also positively modulated the astroglial functions evaluated. Moreover, we demonstrated that heme oxygenase 1 (HO1), an enzyme that is part of the cellular defense system, mediated some of the effects of resveratrol. In conclusion, the mechanisms of the putative protective role of resveratrol against ammonia toxicity involve the modulation of pathways and molecules related to glutamate communication in astroglial cells.

  12. Study on pyrolysis characteristics of lignocellulosic biomass impregnated with ammonia source.

    Science.gov (United States)

    Li, Kai; Zhu, Changpeng; Zhang, Liqiang; Zhu, Xifeng

    2016-06-01

    The current study presents the pyrolysis characteristics of rice husk impregnated with different kinds of ammonia source (ammonium acetate, urea, ammonium sulfate and ammonium dihydrogen phosphate) in a fixed bed reactor. The introduction of ammonia source in pyrolysis process achieved the conversation from carbonyl compounds to nitrogenous heterocyclic compounds. The liquid product of urea-impregnated biomass has higher content of nitrogenous heterocyclic compounds (8.35%) and phenols (30.4%). For ammonium sulfate and ammonium dihydrogen phosphate-impregnated biomass, the quantity of compounds in liquid products reduces remarkably, and the gas products are rich in CO and H2. All the solid products of pyrolysis have great potential application in biochar-based fertilizer and activated carbon for their high N content.

  13. Ammonia Sensor Using Wavelength Modulation Spectroscopy

    KAUST Repository

    Farooq, Aamir

    2015-09-01

    An ammonia sensor can include a laser detector configured to provide stable sample readings. The sensor can implement a method including processing the recorded intensity of the laser beam to determine a first harmonic component and a second harmonic component and the amount of ammonia in the sample.

  14. Oxidative and nitrosative stress in ammonia neurotoxicity.

    Science.gov (United States)

    Skowrońska, Marta; Albrecht, Jan

    2013-04-01

    Increased ammonia accumulation in the brain due to liver dysfunction is a major contributor to the pathogenesis of hepatic encephalopathy (HE). Fatal outcome of rapidly progressing (acute) HE is mainly related to cytotoxic brain edema associated with astrocytic swelling. An increase of brain ammonia in experimental animals or treatment of cultured astrocytes with ammonia generates reactive oxygen and nitrogen species in the target tissues, leading to oxidative/nitrosative stress (ONS). In cultured astrocytes, ammonia-induced ONS is invariably associated with the increase of the astrocytic cell volume. Interrelated mechanisms underlying this response include increased nitric oxide (NO) synthesis which is partly coupled to the activation of NMDA receptors and increased generation of reactive oxygen species by NADPH oxidase. ONS and astrocytic swelling are further augmented by excessive synthesis of glutamine (Gln) which impairs mitochondrial function following its accumulation in there and degradation back to ammonia ("the Trojan horse" hypothesis). Ammonia also induces ONS in other cell types of the CNS: neurons, microglia and the brain capillary endothelial cells (BCEC). ONS in microglia contributes to the central inflammatory response, while its metabolic and pathophysiological consequences in the BCEC evolve to the vasogenic brain edema associated with HE. Ammonia-induced ONS results in the oxidation of mRNA and nitration/nitrosylation of proteins which impact intracellular metabolism and potentiate the neurotoxic effects. Simultaneously, ammonia facilitates the antioxidant response of the brain, by activating astrocytic transport and export of glutathione, in this way increasing the availability of precursors of neuronal glutathione synthesis.

  15. Ammonia sensors and their applications - a review

    NARCIS (Netherlands)

    Timmer, Björn; Olthuis, Wouter; Berg, van den Albert

    2005-01-01

    Many scientific papers have been written concerning gas sensors for different sensor applications using several sensing principles. This review focuses on sensors and sensor systems for gaseous ammonia. Apart from its natural origin, there are many sources of ammonia, like the chemical industry or i

  16. Ammonia and hydrogen sulfide removal using biochar

    Science.gov (United States)

    Reducing ammonia and hydrogen sulfide emissions from livestock facilities is an important issue for many communities and livestock producers. Ammonia has been regarded as odorous, precursor for particulate matter (PM), and contributed to livestock mortality. Hydrogen sulfide is highly toxic at elev...

  17. Chilled Ammonia Process for CO2 Capture

    DEFF Research Database (Denmark)

    Darde, Victor Camille Alfred; Thomsen, Kaj; Well, Willy J.M. van

    2010-01-01

    The chilled ammonia process absorbs the CO2 at low temperature (2–10°C). The heat of absorption of carbon dioxide by ammonia is significantly lower than for amines. In addition, degradation problems can be avoided and a high carbon dioxide capacity is achieved. Hence, this process shows good...

  18. Chilled ammonia process for CO2 capture

    DEFF Research Database (Denmark)

    Darde, Victor Camille Alfred; Thomsen, Kaj; van Well, Willy J. M

    2009-01-01

    The chilled ammonia process absorbs the CO2 at low temperature (2-10 degrees C). The heat of absorption of carbon dioxide by ammonia is significantly lower than for amines. In addition, degradation problems can be avoided and a high carbon dioxide capacity is achieved. Hence, this process shows...

  19. The kinetics of process dependent ammonia inhibition of methanogenesis from acetic acid.

    Science.gov (United States)

    Wilson, Christopher Allen; Novak, John; Takacs, Imre; Wett, Bernhard; Murthy, Sudhir

    2012-12-01

    Advanced anaerobic digestion processes aimed at improving the methanization of sewage sludge may be potentially impaired by the production of inhibitory compounds (e.g. free ammonia). The result of methanogenic inhibition is relatively high effluent concentrations of acetic acid and other soluble organics, as well as reduced methane yields. An extreme example of such an advanced process is the thermal hydrolytic pretreatment of sludge prior to high solids digestion (THD). Compared to a conventional mesophilic anaerobic digestion process (MAD), THD operates in a state of constant inhibition driven by high free ammonia concentrations, and elevated pH values. As such, previous investigations of the kinetics of methanogenesis from acetic acid under uninhibited conditions do not necessarily apply well to the modeling of extreme processes such as THD. By conducting batch ammonia toxicity assays using biomass from THD and MAD reactors, we compared the response of these communities over a broad range of ammonia inhibition. For both processes, increased inhibitor concentrations resulted in a reduction of biomass growth rate (r(max) = μ(max)∙X) and a resulting decrease in the substrate half saturation coefficient (K(S)). These two parameters exhibited a high degree of correlation, suggesting that for a constant transport limited system, the K(S) was mostly a linear function of the growth rate. After correcting for reactor pH and temperature, we found that the THD and MAD biomass were both able to perform methanogenesis from acetate at high free ammonia concentrations (equivalent to 3-5 g/L total ammonia nitrogen), albeit at less than 30% of their respective maximum rates. The reduction in methane production was slightly less pronounced for the THD biomass than for MAD, suggesting that the long term exposure to ammonia had selected for a methanogenic pathway less dependent on those organisms most sensitive to ammonia inhibition (i.e. aceticlastic methanogens).

  20. Ammonia tolerant enriched methanogenic cultures as bioaugmentation inocula to alleviate ammonia inhibition in continuous anaerobic reactors

    DEFF Research Database (Denmark)

    Fotidis, Ioannis; Wang, Han; Angelidaki, Irini

    Ammonia is the most common inhibitor of anaerobic digestion (AD) process, resulting in suboptimal exploitation of the biogas potential of the feedstocks, causing significant economic losses to the biogas plants. Ammonia is mainly inhibiting the aceticlastic methanogens, while the hydrogenotrophic...... of ammonia-rich organic waste in full-scale continuous reactors.......Ammonia is the most common inhibitor of anaerobic digestion (AD) process, resulting in suboptimal exploitation of the biogas potential of the feedstocks, causing significant economic losses to the biogas plants. Ammonia is mainly inhibiting the aceticlastic methanogens, while the hydrogenotrophic...... methanogens are more robust to ammonia toxicity effect. It has been shown that bioaugmentation of a pure strain of a hydrogenotrophic methanogen (i.e. Methanoculleus bourgensis) in an ammonia inhibited continuous anaerobic reactor can improve methane production more than 30%. Nevertheless, cultivation...

  1. From betaines to anionic N-heterocyclic carbenes. Borane, gold, rhodium, and nickel complexes starting from an imidazoliumphenolate and its carbene tautomer

    Directory of Open Access Journals (Sweden)

    Ming Liu

    2016-12-01

    Full Text Available The mesomeric betaine imidazolium-1-ylphenolate forms a borane adduct with tris(pentafluorophenylborane by coordination with the phenolate oxygen, whereas its NHC tautomer 1-(2-phenolimidazol-2-ylidene reacts with (triphenylphosphinegold(I chloride to give the cationic NHC complex [Au(NHC2][Cl] by coordination with the carbene carbon atom. The anionic N-heterocyclic carbene 1-(2-phenolateimidazol-2-ylidene gives the complexes [K][Au(NHC−2], [Rh(NHC−3] and [Ni(NHC−2], respectively. Results of four single crystal analyses are presented.

  2. Clinical utility of breath ammonia for evaluation of ammonia physiology in healthy and cirrhotic adults.

    Science.gov (United States)

    Spacek, Lisa A; Mudalel, Matthew; Tittel, Frank; Risby, Terence H; Solga, Steven F

    2015-12-01

    Blood ammonia is routinely used in clinical settings to assess systemic ammonia in hepatic encephalopathy and urea cycle disorders. Despite its drawbacks, blood measurement is often used as a comparator in breath studies because it is a standard clinical test. We sought to evaluate sources of measurement error and potential clinical utility of breath ammonia compared to blood ammonia. We measured breath ammonia in real time by quartz enhanced photoacoustic spectrometry and blood ammonia in 10 healthy and 10 cirrhotic participants. Each participant contributed 5 breath samples and blood for ammonia measurement within 1 h. We calculated the coefficient of variation (CV) for 5 breath ammonia values, reported medians of healthy and cirrhotic participants, and used scatterplots to display breath and blood ammonia. For healthy participants, mean age was 22 years (±4), 70% were men, and body mass index (BMI) was 27 (±5). For cirrhotic participants, mean age was 61 years (±8), 60% were men, and BMI was 31 (±7). Median blood ammonia for healthy participants was within normal range, 10 μmol L(-1) (interquartile range (IQR), 3-18) versus 46 μmol L(-1) (IQR, 23-66) for cirrhotic participants. Median breath ammonia was 379 pmol mL(-1) CO2 (IQR, 265-765) for healthy versus 350 pmol mL(-1) CO2 (IQR, 180-1013) for cirrhotic participants. CV was 17  ±  6%. There remains an important unmet need in the evaluation of systemic ammonia, and breath measurement continues to demonstrate promise to fulfill this need. Given the many differences between breath and blood ammonia measurement, we examined biological explanations for our findings in healthy and cirrhotic participants. We conclude that based upon these preliminary data breath may offer clinically important information this is not provided by blood ammonia.

  3. Ammonia gas permeability of meat packaging materials.

    Science.gov (United States)

    Karim, Faris; Hijaz, Faraj; Kastner, Curtis L; Smith, J Scott

    2011-03-01

    Meat products are packaged in polymer films designed to protect the product from exterior contaminants such as light, humidity, and harmful chemicals. Unfortunately, there is almost no data on ammonia permeability of packaging films. We investigated ammonia permeability of common meat packaging films: low-density polyethylene (LDPE; 2.2 mil), multilayer polyolefin (MLP; 3 mil), and vacuum (V-PA/PE; 3 mil, 0.6 mil polyamide/2.4 mil polyethylene). The films were fabricated into 10 × 5 cm pouches and filled with 50 mL deionized water. Pouches were placed in a plexiglass enclosure in a freezer and exposed to 50, 100, 250, or 500 ppm ammonia gas for 6, 12, 24, and 48 h at -17 ± 3 °C and 21 ± 3 °C. At freezing temperatures, no ammonia residues were detected and no differences in pH were found in the water. At room temperature, ammonia levels and pH of the water increased significantly (P packaging materials have low ammonia permeability and protect meat products exposed to ammonia leaks during frozen storage.

  4. Low-cost anodes for ammonia electrooxidation

    Science.gov (United States)

    Selverston, Steven M.

    This research focused on the development of low-cost electrodes for the electrochemical oxidation of ammonia to nitrogen, a reaction that has possible applications in hydrogen generation, direct ammonia fuel cells, water treatment, and sensors. Statistical design of experiments was used to help develop an efficient and scalable process for electrodeposition of platinum with a specific electrochemical surface area of over 25 m2 /g. Catalyst surface area and activity were evaluated using cyclic voltammetry, and the material microstructure and morphology were investigated using x-ray diffraction and scanning electron microscopy. The synthesized electrodes were found to be active toward the ammonia electrooxidation reaction, particularly when supporting electrolyte was added. However, supporting electrolyte was not required in order to oxidize the ammonia. As proof of concept, a homemade direct ammonia fuel cell employing a commercial anion exchange membrane was tested at room temperature with gravity-fed fuel and without supporting electrolyte. At room temperature, with passive reactant supply and using dissolved oxygen at the cathode, the cell produced about one quarter the power of a direct methanol fuel cell that used active transport of humidified oxygen and preheated (50 °C) methanol. With continued development of the membrane, cathode and membrane electrode assembly, the passive direct ammonia fuel cell using anion exchange membrane could have performance similar to the equivalent direct methanol fuel cell, and it could benefit from many advantages of ammonia over methanol such as lower cost, higher energy density, and reduced greenhouse gas emissions.

  5. Resveratrol prevents ammonia toxicity in astroglial cells.

    Directory of Open Access Journals (Sweden)

    Larissa Daniele Bobermin

    Full Text Available Ammonia is implicated as a neurotoxin in brain metabolic disorders associated with hyperammonemia. Acute ammonia toxicity can be mediated by an excitotoxic mechanism, oxidative stress and nitric oxide (NO production. Astrocytes interact with neurons, providing metabolic support and protecting against oxidative stress and excitotoxicity. Astrocytes also convert excess ammonia and glutamate into glutamine via glutamine synthetase (GS. Resveratrol, a polyphenol found in grapes and red wines, exhibits antioxidant and anti-inflammatory properties and modulates glial functions, such as glutamate metabolism. We investigated the effect of resveratrol on the production of reactive oxygen species (ROS, GS activity, S100B secretion, TNF-α, IL-1β and IL-6 levels in astroglial cells exposed to ammonia. Ammonia induced oxidative stress, decreased GS activity and increased cytokines release, probably by a mechanism dependent on protein kinase A (PKA and extracellular signal-regulated kinase (ERK pathways. Resveratrol prevented ammonia toxicity by modulating oxidative stress, glial and inflammatory responses. The ERK and nuclear factor-κB (NF-κB are involved in the protective effect of resveratrol on cytokines proinflammatory release. In contrast, other antioxidants (e.g., ascorbic acid and trolox were not effective against hyperammonemia. Thus, resveratrol could be used to protect against ammonia-induced neurotoxicity.

  6. The aerosols' fate in a putative ammonia ocean on Titan

    Science.gov (United States)

    Ramírez, S. I.; Coll, P.; Buch, A.; Brassé, C.; Poch, O.; Raulin, F.

    2010-04-01

    -methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide in dimethylformamide, the products were identified and quantified by a GC-MS system. We found derived residues related to amino acids as well as urea, as shown by their mass spectra and chromatographic patterns. There seems to be a constant presence of alanine and glycine, no matter the ammonia concentrations to which the analogues were exposed. Our results have important astrobiological implications to Titan's environment particularly if the existence of the suggested subsurface water-ammonia liquids is validated. Titan is a place where organic compounds are produced and where liquid water might be present. Therefore, this kind of studies helps to better understand the geological processes of Titan's surface and its relationship with the active organic chemistry occurring in its atmosphere.

  7. Ammonia-oxidizing archaea have more important role than ammonia-oxidizing bacteria in ammonia oxidation of strongly acidic soils.

    Science.gov (United States)

    Zhang, Li-Mei; Hu, Hang-Wei; Shen, Ju-Pei; He, Ji-Zheng

    2012-05-01

    Increasing evidence demonstrated the involvement of ammonia-oxidizing archaea (AOA) in the global nitrogen cycle, but the relative contributions of AOA and ammonia-oxidizing bacteria (AOB) to ammonia oxidation are still in debate. Previous studies suggest that AOA would be more adapted to ammonia-limited oligotrophic conditions, which seems to be favored by protonation of ammonia, turning into ammonium in low-pH environments. Here, we investigated the autotrophic nitrification activity of AOA and AOB in five strongly acidic soils (pHnitrification inhibitor dicyandiamide (DCD) completely inhibited the nitrification activity and CO(2) fixation by AOA, accompanied by decreasing thaumarchaeal amoA gene abundance. Bacterial amoA gene abundance decreased in all microcosms irrespective of DCD addition, and mostly showed no correlation with nitrate concentrations. Phylogenetic analysis of thaumarchaeal amoA gene and 16S rRNA gene revealed active (13)CO(2)-labeled AOA belonged to groups 1.1a-associated and 1.1b. Taken together, these results provided strong evidence that AOA have a more important role than AOB in autotrophic ammonia oxidation in strongly acidic soils.

  8. Colonic luminal ammonia and portal blood L-glutamine and L-arginine concentrations: a possible link between colon mucosa and liver ureagenesis.

    Science.gov (United States)

    Eklou-Lawson, Mamy; Bernard, Françoise; Neveux, Nathalie; Chaumontet, Catherine; Bos, Cécile; Davila-Gay, Anne-Marie; Tomé, Daniel; Cynober, Luc; Blachier, François

    2009-10-01

    The highest ammonia concentration in the body is found in the colon lumen and although there is evidence that this metabolite can be absorbed through the colonic epithelium, there is little information on the capacity of the colonic mucosa to transfer and metabolize this compound. In the present study, we used a model of conscious pig with a canula implanted into the proximal colon to inject endoluminally increasing amounts of ammonium chloride and to measure during 5 h the kinetics of ammonia and amino acid concentration changes in the portal and arterial blood. By injecting as a single dose from 1 to 5 g ammonia into the colonic lumen, a dose-related increase in ammonia concentration in the portal blood was recorded. Ammonia concentration remained unchanged in the arterial blood except for the highest dose tested, i.e. 5 g which thus apparently exceeds the hepatic ureagenesis capacity. By calculating the apparent net ammonia absorption, it was determined that the pig colonic epithelium has the capacity to absorb 4 g ammonia. Ammonia absorption through the colonic epithelium was concomitant with increase of L-glutamine and L-arginine concentrations in the portal blood. This coincided with the expression of both glutamate dehydrogenase and glutamine synthetase in isolated colonic epithelial cells. Since L-glutamine and L-arginine are known to represent activators for liver ureagenesis, we propose that increased portal concentrations of these amino acids following increased ammonia colonic luminal concentration represent a metabolic link between colon mucosa and liver urea biosynthesis.

  9. Ammonia as a Suitable Fuel for Fuel Cells

    OpenAIRE

    Lan, Rong; Tao, Shanwen

    2014-01-01

    Ammonia, an important basic chemical, is produced at a scale of 150 million tons per year. Half of hydrogen produced in chemical industry is used for ammonia production. Ammonia containing 17.5 wt% hydrogen is an ideal carbon-free fuel for fuel cells. Compared to hydrogen, ammonia has many advantages. In this mini-review, the suitability of ammonia as fuel for fuel cells, the development of different types of fuel cells using ammonia as the fuel and the potential applications of ammonia fuel ...

  10. INDUCCIÓN DE FENILALANINA AMONIO LIASA Y VARIACIÓN EN EL CONTENIDO DE COMPUESTOS FENÓLICOS EN FRUTOS DE LULO (Solanum quitoense Lam INFECTADOS CON Colletotrichum acutatum. Induction of phenylalanine ammonia lyase and variation in phenolic compounds content in Lulo fruits (Solanum quitoense Lam infected by Colletotrichum acutatum

    Directory of Open Access Journals (Sweden)

    MAIRA ANDREA ARRIETA-GUEVARA

    Full Text Available Se evaluó la dinámica de la actividad fenilalanina amonio liasa (PAL en corteza de frutos de lulo (Solanum quitoense Lam con el fin de determinar su participación en respuestas bioquímicas hacia Colletotrichum acutatum. Se establecieron como mejores condiciones para la extracción de la enzima, buffer ácido bórico-borato de sodio 0.1M pH 8.8, 1% SDS, 3% PVPP y para medir la actividad, sustrato L-fenilalanina 5 mM , pH 8,0, 20°C , 30 ΜL de extracto y 45 min. Se realizó un ensayo in vivo usando frutos en tres estados de madurez, los cuales fueron inoculados con el patógeno o tratados con agua estéril. A cinco tiempos (hpi = horas post-infección se determinó la actividad PAL y el contenido total de fenoles, encontrándose que hay una respuesta diferencial de la enzima por efecto del patógeno y por el estado de madurez. Para frutos en el estado pintón se obtuvo el mayor aumento de PAL, el que perduró hasta 48 hpi, al compararlo con los controles y con los otros dos estados de madurez. Este aumento mostró relación con un marcado incremento en el contenido total de fenoles y con el desarrollo más tardío de síntomas característicos de antracnosis, observado para los frutos pintones. Estos resultados permiten postular, una posible relación positiva entre inducción de PAL, aumento de fenólicos y respuesta de tolerancia a C. acutatum. Para lulos en estado verde y maduro se observó aumento de PAL a 12 y 24 hpi que coincidió también con incremento en el contenido de fenoles totales, aunque para estos dos últimos estados dicho contenido disminuyó significativamente a tiempos mayores.Phenylalanine ammonia lyase (PAL activity induction was evaluated in lulo fruits to determine the role of this enzyme in biochemical responses towards the pathogen Colletotrichum acutatum. We studied the experimental conditions to obtain the enzyme, using lulo peel, and found that the best conditions for extraction were buffer of boric acid

  11. Physiological plasticity of the thermophilic ammonia oxidizing archaeon Nitrosocaldus yellowstonii in response to a changing environment

    Science.gov (United States)

    Jewell, T.; Johnson, A.; Gelsinger, D.; de la Torre, J. R.

    2012-12-01

    Our understanding of nitrogen biogeochemical cycling in high temperature environments underwent a dramatic revision with the discovery of ammonia oxidizing archaea (AOA). The importance of AOA to the global nitrogen cycle came to light when recent studies of marine AOA demonstrated the dominance of these organisms in the ocean microbiome and their role as producers of the greenhouse gas nitrous oxide (N2O). Understanding how AOA respond to fluctuating environments is crucial to fully comprehending their contribution to global biogeochemical cycling and climate change. In this study we use the thermophilic AOA Nitrosocaldus yellowstonii strain HL72 to explore the physiological plasticity of energy metabolism in these organisms. Previous studies have shown that HL72 grows autotrophically by aerobically oxidizing ammonia (NH3) to nitrite (NO2-). Unlike studies of marine AOA, we find that HL72 can grow over a wide ammonia concentration range (0.25 - 10 mM NH4Cl) with comparable generation times when in the presence of 0.25 to 4 mM NH4Cl. However, preliminary data indicate that amoA, the alpha subunit of ammonia monooxygenase (AMO), is upregulated at low ammonia concentrations (urea transporter. Urea ((NH2)2CO) is an organic compound ubiquitous to aquatic and soil habitats that, when hydrolyzed, forms NH3 and CO2. We examined urea as an alternate source of ammonia for the ammonia oxidation pathway. HL72 grows over a wide range of urea concentrations (0.25 - 10 mM) at rates comparable to growth on ammonia. In a substrate competition experiment HL72 preferentially consumed NH3 from NH4Cl when both substrates were provided in equal molar concentrations. However, the urease alpha subunit ureC was expressed in both the presence and absence of urea. One consequence of urea hydrolysis is consumption of intracellular protons during the reaction. As ammonia oxidation produces H+, leading to a decrease in pH, the hydrolysis of urea prior to ammonia oxidation may help alleviate

  12. Ammonia measurement with a pH electrode in the ammonia/urea-SCR process

    Science.gov (United States)

    Kröcher, Oliver; Elsener, Martin

    2007-03-01

    The selective catalytic reduction of nitrogen oxides with ammonia (ammonia SCR) and urea (urea SCR), respectively, is a widespread process to clean flue and diesel exhaust gases due to its simplicity and efficiency. The main challenge of the process is to minimize the ammonia emissions downstream of the SCR catalyst. We found that ammonia emissions of >10 ppm can reliably be detected with a simple pH electrode in the presence of CO2, SOx, NOx, and moderately weak organic acids. 10-20 ppm of ammonia in the exhaust gas are sufficient to neutralize the acids and to increase the pH value from 3 to 6. On this basis a continuous measuring method for ammonia was developed, which was used to control the dosage of urea in the SCR process. While keeping the ammonia emissions after the SCR catalyst at 5-30 ppm an average NOx removal efficiency (DeNOx) of >95% were achieved at a diesel test rig. The method can also be applied for exhaust gases with higher acid contents, if a basic pre-filter is added adsorbing the acidic exhaust components. Compared to water as absorption solution, more precise ammonia measurements are possible, if a 0.1 M NH4Cl absorption solution is applied, whose pH value is changing as a Nernst function of the ammonia concentration.

  13. Ammonia transformation in a biotrickling air filter

    DEFF Research Database (Denmark)

    Nielsen, Lars Peter; Nielsen, Marie Louise; Andersen, Mathias;

    2007-01-01

    measurements and model was obtained by using conventional substrate and inhibition kinetics of ammonium and nitrite oxidizing bacteria. Highest rates of ammonia removal were observed in the central section of the filter. Near the air outlet and water inlet the process was ammonia limited, while high nitrous...... acid concentrations almost excluded any biological activity near the air inlet and water outlet. Nitrous acid inhibition also stabilized pH at 6.5-7 all through the filter. Being sensitive to both ammonia and nitrous acid the nitrite oxidation process occurred mainly in the filter sections near the air...... outlet / water inlet, and only 8% of the nitrite was turned into nitrate. Water supply only exceeded evaporation by 20% but modelling indicated that additional watering would have limited effect on filter efficiency. The filter was also robust to varying loading, as a 4-fold increase in ammonia inlet...

  14. Ammonia Affects Astroglial Proliferation in Culture.

    Directory of Open Access Journals (Sweden)

    Guillermo Bodega

    Full Text Available Primary cultures of rat astroglial cells were exposed to 1, 3 and 5 mM NH4Cl for up to 10 days. Dose- and time-dependent reductions in cell numbers were seen, plus an increase in the proportion of cells in the S phase. The DNA content was reduced in the treated cells, and BrdU incorporation diminished. However, neither ammonia nor ammonia plus glutamine had any effect on DNA polymerase activity. iTRAQ analysis showed that exposure to ammonia induced a significant reduction in histone and heterochromatin protein 1 expression. A reduction in cell viability was also noted. The ammonia-induced reduction of proliferative activity in these cultured astroglial cells seems to be due to a delay in the completion of the S phase provoked by the inhibition of chromatin protein synthesis.

  15. 21 CFR 573.180 - Anhydrous ammonia.

    Science.gov (United States)

    2010-04-01

    ... silage. (2)(i) The food additive anhydrous ammonia is applied directly to corn plant material for use in... to corn plant material containing 28 to 38 percent dry matter. (iv) The silage treated with...

  16. Nitrocarburising in ammonia-hydrocarbon gas mixtures

    DEFF Research Database (Denmark)

    Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

    2010-01-01

    The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammoniapropene- hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere...

  17. Aqueous Ammonia soaking of digested manure fibers

    DEFF Research Database (Denmark)

    Mirtsou-Xanthopoulou, Chrysoula; Jurado, Esperanza; Skiadas, Ioannis

    2012-01-01

    , their economical profitable operation relies on increasing the methane yield from manure, and especially of its solid fraction which is not so easily degradable. In the present study, Aqueous Ammonia Soaking was successfully applied on digested fibers separated from the effluent of a manure-fed, full......-scale anaerobic digester to enhance their methane productivity. Soaking in six different reagent concentrations in ammonia (5%, 10%, 15%, 20%, 25%, 32%) was applied for 3 days at 22°C. An overall methane yield increase from 85% to 110% was achieved compared to controls (digested manure fibers where AAS...... was not applied). The difference in reagent concentration at the range of 5-25% w/w in ammonia did not affect that much the overall methane yield resulting to an increase of 104-110% compared to the non AAS-treated fibers. Thus, an ammonia concentration as low as 5% is adequate for achieving the same increase...

  18. Ammonia and urea permeability of mammalian aquaporins

    DEFF Research Database (Denmark)

    Litman, Thomas; Søgaard, Rikke; Zeuthen, Thomas

    2009-01-01

    The human aquaporins,AQP3,AQP7, AQP8,AQP9, and possibly AQP10, are permeable to ammonia, and AQP7, AQP9, and possibly AQP3, are permeable to urea. In humans, these aquaporins supplement the ammonia transport of the Rhesus (Rh) proteins and the urea transporters (UTs). The mechanism by which...... ammonium is transported by aquaporins is not fully resolved. A comparison of transport equations, models, and experimental data shows that ammonia is transported in its neutral form, NH(3). In the presence of NH(3), the aquaporin stimulates H(+) transport. Consequently, this transport of H(+) is only...... significant at alkaline pH. It is debated whether the H(+) ion passes via the aquaporin or by some external route; the investigation of this problem requires the aquaporin-expressing cell to be voltage-clamped. The ammonia-permeable aquaporins differ from other aquaporins by having a less restrictive aromatic...

  19. Ammonia oxidation, denitrification and dissimilatory nitrate reduction to ammonium in two US Great Basin hot springs with abundant ammonia-oxidizing archaea.

    Science.gov (United States)

    Dodsworth, Jeremy A; Hungate, Bruce A; Hedlund, Brian P

    2011-08-01

    Many thermophiles catalyse free energy-yielding redox reactions involving nitrogenous compounds; however, little is known about these processes in natural thermal environments. Rates of ammonia oxidation, denitrification and dissimilatory nitrate reduction to ammonium (DNRA) were measured in source water and sediments of two ≈ 80°C springs in the US Great Basin. Ammonia oxidation and denitrification occurred mainly in sediments. Ammonia oxidation rates measured using (15)N-NO(3)(-) pool dilution ranged from 5.5 ± 0.8 to 8.6 ± 0.9 nmol N g(-1) h(-1) and were unaffected or only mildly stimulated by amendment with NH(4) Cl. Denitrification rates measured using acetylene block ranged from 15.8 ± 0.7 to 51 ± 12 nmol N g(-1) h(-1) and were stimulated by amendment with NO(3)(-) and complex organic compounds. The DNRA rate in one spring sediment measured using an (15)N-NO(3)(-) tracer was 315 ± 48 nmol N g(-1) h(-1). Both springs harboured distinct planktonic and sediment microbial communities. Close relatives of the autotrophic, ammonia-oxidizing archaeon 'Candidatus Nitrosocaldus yellowstonii' represented the most abundant OTU in both spring sediments by 16S rRNA gene pyrotag analysis. Quantitative PCR (qPCR) indicated that 'Ca. N. yellowstonii'amoA and 16S rRNA genes were present at 3.5-3.9 × 10(8) and 6.4-9.0 × 10(8) copies g(-1) sediment. Potential denitrifiers included members of the Aquificales and Thermales. Thermus spp. comprised springs and suggest that ammonia oxidation may be a major source of energy fuelling primary production.

  20. On-line determination of ammonia at low pptv mixing ratios in the CLOUD chamber

    CERN Document Server

    Bianchi, F; Mathot, S; Baltensperger, U

    2012-01-01

    A new instrument for the on-line determination of ammonia was developed. Since ammonia is a rather sticky compound, sampling losses were minimised with a new sam- pling device where the ammonia was transferred to the liq- uid phase only 5 mm after the inlet tip. The liquid phase was then analyzed by long pathlength absorption spectrophotom- etry using the Berthelot reaction with phenol and hypochlo- rite as reagents. The measurements were made during the CLOUD3 campaign at CERN where the influence of ammo- nia on the nucleation rate was studied. At stable conditions the detection limit reached with this instrument was 35 pptv (air flow rate of 2 l min − 1 , liquid flow rate of 0.3 ml min − 1 ), although occasionally the instrument was affected by back- ground problems. The range of mixing ratios during this campaign was varied from the background contamination ( < 35 pptv) up to around 2 ppbv. The measured ammonia concentration was correlated with the rate of ammonia in- jected into the chamber, but wi...

  1. Corrosion inhibitor for aqueous ammonia absorption system

    Science.gov (United States)

    Phillips, Benjamin A.; Whitlow, Eugene P.

    1998-09-22

    A method of inhibiting corrosion and the formation of hydrogen and thus improving absorption in an ammonia/water absorption refrigeration, air conditioning or heat pump system by maintaining the hydroxyl ion concentration of the aqueous ammonia working fluid within a selected range under anaerobic conditions at temperatures up to 425.degree. F. This hydroxyl ion concentration is maintained by introducing to the aqueous ammonia working fluid an inhibitor in an amount effective to produce a hydroxyl ion concentration corresponding to a normality of the inhibitor relative to the water content ranging from about 0.015 N to about 0.2 N at 25.degree. C. Also, working fluids for inhibiting the corrosion of carbon steel and resulting hydrogen formation and improving absorption in an ammonia/water absorption system under anaerobic conditions at up to 425.degree. F. The working fluids may be aqueous solutions of ammonia and a strong base or aqueous solutions of ammonia, a strong base, and a specified buffer.

  2. Ammonia transformations and abundance of ammonia oxidizers in a clay soil underlying a manure pond.

    Science.gov (United States)

    Sher, Yonatan; Baram, Shahar; Dahan, Ofer; Ronen, Zeev; Nejidat, Ali

    2012-07-01

    Unlined manure ponds are constructed on clay soil worldwide to manage farm waste. Seepage of ammonia-rich liquor into underlying soil layers contributes to groundwater contamination by nitrate. To identify the possible processes that lead to the production of nitrate from ammonia in this oxygen-limited environment, we studied the diversity and abundance of ammonia-transforming microorganisms under an unlined manure pond. The numbers of ammonia-oxidizing bacteria and anammox bacteria were most abundant in the top of the soil profile and decreased significantly with depth (0.5 m), correlating with soil pore-water ammonia concentrations and soil ammonia concentrations, respectively. On the other hand, the numbers of ammonia-oxidizing archaea were relatively constant throughout the soil profile (10(7) amoA copies per g(soil)). Nitrite-oxidizing bacteria were detected mainly in the top 0.2 m. The results suggest that nitrate accumulation in the vadose zone under the manure pond could be the result of complete aerobic nitrification (ammonia oxidation to nitrate) and could exist as a byproduct of anammox activity. While the majority of the nitrogen was removed within the 0.5-m soil section, possibly by combined anammox and heterotrophic denitrification, a fraction of the produced nitrate leached into the groundwater.

  3. Complex-compound low-temperature TES system

    Energy Technology Data Exchange (ETDEWEB)

    Rockenfeller, U. [Rocky Research, Boulder City, NV (United States)

    1989-03-01

    Development of a complex-compound low-temperature TES system is described herein from basic chemical principles through current bench scale system development. Important application engineering issues and an economic outlook are addressed as well. The system described uses adsorption reactions between solid metal inorganic salts and ammonia refrigerant. It is the coordinative nature of these reactions that allows for storage of ammonia refrigerant within the solid salt crystals that function as a chemical compressor during on peak periods (substituting the mechanical compressor) and release ammonia during off peak periods while a mechanical vapor compression system provides the necessary reactor pressure and heat.

  4. Governing processes for reactive nitrogen compounds in the European atmosphere

    DEFF Research Database (Denmark)

    Hertel, Ole; Skjøth, Carsten Ambelas; Reis, S.;

    2012-01-01

    Reactive nitrogen (N-r) compounds have different fates in the atmosphere due to differences in the governing processes of physical transport, deposition and chemical transformation. N-r compounds addressed here include reduced nitrogen (NHx: ammonia (NH3) and its reaction product ammonium (NH4+))...

  5. Electron-induced ammonia adsorption on iron

    CERN Document Server

    Narkiewicz, U; Trybuchowicz, A; Arabczyk, W

    2003-01-01

    The adsorption of ammonia on an iron surface at ambient temperature has been investigated using Auger electron spectroscopy (AES). The effect of the electron beam on the process of the ammonia adsorption has been studied. The polycrystalline iron samples precovered with different amounts of oxygen (0.15-1 ML) or sulphur (1 ML) were used. The initial sticking coefficient of ammonia to oxygen precovered iron surface was estimated as s sub 0 approx 5x10 sup - sup 4 (independently on the oxygen coverage) for the adsorption experiments without the effect of the electron beam. The strong inhibiting effect of sulphur precoverage on the ammonia adsorption has been found (s sub 0 approx 6.5x10 sup - sup 6). The electron beam has favourable effect on the adsorption of ammonia, and this effect increases with the oxygen coverage (one monolayer of adsorbed nitrogen atoms at the saturation state and s sub 0 approx 1 for the iron surface precovered with one monolayer of oxygen). The proposed explanation is the favourable ef...

  6. Ammonia/Hydrogen Mixtures in an SI-Engine

    DEFF Research Database (Denmark)

    Mørch, Christian Sandersen; Bjerre, Andreas; Gøttrup, Morten Piil

    2011-01-01

    In recent years there has been increasing focus on using metal ammine complexes for ammonia storage. In this paper a fuel system for ammonia fuelled internal combustion engines using metal ammine complexes as ammonia storage is analyzed. The use of ammonia/hydrogen mixtures as an SI-engine fuel...... is investigated in the same context. Ammonia and hydrogen were introduced into the intake manifold of a CFR-engine. Series of experiments with varying excess air ratio and different ammonia to hydrogen ratios was conducted. This showed that a fuel mixture with 10 vol.% hydrogen performs best with respect...

  7. The effect of outside conditions on anaerobic ammonia oxidation reaction

    Institute of Scientific and Technical Information of China (English)

    YANG Min; WANG Shu-bo

    2016-01-01

    Organic carbon, inorganic carbon, temperature, pH and ORP are all to have a certain influence on the anaerobic ammonia oxidation reaction. We can draw some conclusions on the optimum conditions of anaerobic ammonia oxidation reaction. The optimum temperature of the anaerobic ammonia oxidation reaction is 30-35℃. And the optimum pH of the anaerobic ammonia reaction is 7.5-8.3. The presence of organic matters can affect the anaerobic ammonia reaction, and different organic matters have different influence on it. The concentration of the inorganic carbon also exist great influence on the reaction. High inorganic carbon concentration also can inhibit anaerobic ammonia oxidation reaction.

  8. Gas Turbine Combustion and Ammonia Removal Technology of Gasified Fuels

    Directory of Open Access Journals (Sweden)

    Takeharu Hasegawa

    2010-03-01

    Full Text Available From the viewpoints of securing a stable supply of energy and protecting our global environment in the future, the integrated gasification combined cycle (IGCC power generation of various gasifying methods has been introduced in the world. Gasified fuels are chiefly characterized by the gasifying agents and the synthetic gas cleanup methods and can be divided into four types. The calorific value of the gasified fuel varies according to the gasifying agents and feedstocks of various resources, and ammonia originating from nitrogenous compounds in the feedstocks depends on the synthetic gas clean-up methods. In particular, air-blown gasified fuels provide low calorific fuel of 4 MJ/m3 and it is necessary to stabilize combustion. In contrast, the flame temperature of oxygen-blown gasified fuel of medium calorie between approximately 9–13 MJ/m3 is much higher, so control of thermal-NOx emissions is necessary. Moreover, to improve the thermal efficiency of IGCC, hot/dry type synthetic gas clean-up is needed. However, ammonia in the fuel is not removed and is supplied into the gas turbine where fuel-NOx is formed in the combustor. For these reasons, suitable combustion technology for each gasified fuel is important. This paper outlines combustion technologies and combustor designs of the high temperature gas turbine for various IGCCs. Additionally, this paper confirms that further decreases in fuel-NOx emissions can be achieved by removing ammonia from gasified fuels through the application of selective, non-catalytic denitration. From these basic considerations, the performance of specifically designed combustors for each IGCC proved the proposed methods to be sufficiently effective. The combustors were able to achieve strong results, decreasing thermal-NOx emissions to 10 ppm (corrected at 16% oxygen or less, and fuel-NOx emissions by 60% or more, under conditions where ammonia concentration per fuel heating value in unit volume was 2.4 × 102 ppm

  9. Emissions of sulfur-containing odorants, ammonia, and methane from pig slurry

    DEFF Research Database (Denmark)

    Eriksen, Jørgen; Adamsen, Anders Peter S.; Nørgaard, Jan Værum

    2010-01-01

    Supplementation of benzoic acid to pig diets reduces the pH of urine and may thereby affect emissions of ammonia and other gases from slurry, including sulfur-containing compounds that are expected to play a role in odor emission. Over a period of 112 d, we investigated hydrogen sulfide (H2S...... from the slurry of the control treatment, which came from pigs fed according to Danish recommendations for amino acids and minerals. The emission patterns of volatile S compounds suggested an intense cycling between pools of organic S in the slurries, with urinary sulfate as the main source. Diet...... and benzoic acid treatments, which caused a significant increase in emissions of especially MT, but also of DMDS. In conclusion, addition of 2% benzoic acid to pig diets effectively reduced ammonia volatilization, but interactions with dietary S may increase odor problems....

  10. A personal ammonia monitor utilizing permeation sampling

    Energy Technology Data Exchange (ETDEWEB)

    Benedict, A.F. (Occupational Safety and Health Administration, Baton Rouge, LA); Reiszner, K.D.; West, P.W.

    1983-01-01

    A method has been developed for the determination of the time-weighted-average personal exposure to ammonia. Sample collection was achieved by permeation through a silicone membrane into a boric acid solution. The trapped ammonia was then determined spectrophotometrically with Nessler's reagent or potentiometrically with an ion selective electrode. The device may be used for sampling periods as short as 5 minutes and was not affected by changes in the environmental parameters normally encountered at industrial locations. The detection limit is 0.4 ppm for an 8 hr sampling period and the monitor responds linearly to at least 150 ppm. The Nessler's method may be utilized in industrial environments containing monoethanol amine in conjunction with ammonia with no significant interference. Although some interference was observed from ethylenediamine with the Nessler's technique, little interference was found with the potentiometric determination.

  11. Combinatorial Supports for Ru-based Ammonia Synthesis Catalysts

    Institute of Scientific and Technical Information of China (English)

    Gui Yu HUANG; Jing Dong LIN; Zhong Xiang XU; Dai Wei LIAO

    2005-01-01

    The support materials of ruthenium-based catalysts for ammonia synthesis were prepared using mixed solutions composed of magnesium nitrate, aluminum nitrate and calcium nitrate with a certain ratio. The catalysts supported on complex oxides were more active and the optimal activity temperatures were lower than that supported on single oxide under the same conditions.The catalyst with Mg-Al complex oxide as support prepared by calcinafing hydrotalcite-like compound had significantlyhigher activity, 38.42 mL NH3·h-1·g-1 at 673 K. The BET determination showed that the Mg-Al complex oxide possessed large surface area, 140.95 m2·g-1, similar to γ-Al2O3.

  12. Ammonia emission time profiles based on manure transport data improve ammonia modelling across north western Europe

    Science.gov (United States)

    Hendriks, C.; Kranenburg, R.; Kuenen, J. J. P.; Van den Bril, B.; Verguts, V.; Schaap, M.

    2016-04-01

    Accurate modelling of mitigation measures for nitrogen deposition and secondary inorganic aerosol (SIA) episodes requires a detailed representation of emission patterns from agriculture. In this study the meteorological influence on the temporal variability of ammonia emissions from livestock housing and application of manure and fertilizer are included in the chemistry transport model LOTOS-EUROS. For manure application, manure transport data from Flanders (Belgium) were used as a proxy to derive the emission variability. Using improved ammonia emission variability strongly improves model performance for ammonia, mainly by a better representation of the spring maximum. The impact on model performance for SIA was negligible as explained by the limited, ammonia rich region in which the emission variability was updated. The contribution of Flemish agriculture to modelled annual mean ammonia and SIA concentrations in Flanders were quantified at respectively 7-8 and 1-2 μg/m3. A scenario study was performed to investigate the effects of reducing ammonia emissions from manure application during PM episodes by 75%, yielding a maximum reduction in modelled SIA levels of 1-3 μg/m3 during episodes. Year-to-year emission variability and a soil module to explicitly model the emission process from manure and fertilizer application are needed to further improve the modelling of the ammonia budget.

  13. Deammoniation and ammoniation processes with ammonia complexes

    Directory of Open Access Journals (Sweden)

    Pim Donkers

    2016-12-01

    Full Text Available For selecting the most suitable ammoniate as a heat storage material we have reviewed all the available literature since 1860. This data reveal that we can order the dissociation temperature and the enthalpy of reaction of di erent ammoniates. We show that all data can be represented by a single master curve. This curve shows that ammoniates belonging to the alkali metal periodic group have the lowest energy pro ammonia molecule, whereas transition metals (3d have the highest energy pro ammonia molecule. These trends can be used to select the most suitable ammoniates under certain working conditions.

  14. Enantioselective, iridium-catalyzed monoallylation of ammonia.

    Science.gov (United States)

    Pouy, Mark J; Stanley, Levi M; Hartwig, John F

    2009-08-19

    Highly enantioselective, iridium-catalyzed monoallylations of ammonia are reported. These reactions occur with electron-neutral, -rich, and -poor cinnamyl carbonates, alkyl and trityloxy-substituted allylic carbonates, and dienyl carbonates in moderate to good yields and excellent enantioselectivities. This process is enabled by the use of an iridium catalyst that does not require a Lewis acid for activation and that is stable toward a large excess of ammonia. This selective formation of primary allylic amines allows for one-pot syntheses of heterodiallylamines and allylic amides that are not otherwise accessible via iridium-catalyzed allylic amination without the use of blocking groups and protective group manipulations.

  15. Structure of Ramie Treated by Liquid Ammonia

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The morphology and supermolecular structures of the scoured/bleached ramie and scoured/bleached/liquid ammonia treated ramie were studied by means of scanning electron microscope, X-ray diffractometer, reverse gel permeation chromatography, etc. The results indicate that liquid ammonia treatment of the scoured/bleached ramie leads to a smoother surface, a lower crystallinity, partial crystal transformation from cellulose Ⅰ to cellulose Ⅲ, a decrease in the volume and cumulative surface area of the larger micropores and an increase in those of the smaller ones in the fiber.

  16. Electrochemical ammonia production on molybdenum nitride nanoclusters

    DEFF Research Database (Denmark)

    Howalt, Jakob Geelmuyden; Vegge, Tejs

    2013-01-01

    Theoretical investigations of electrochemical production of ammonia at ambient temperature and pressure on nitrogen covered molybdenum nanoparticles are presented. Density functional theory calculations are used in combination with the computational hydrogen electrode approach to calculate the free...... energy profile for electrochemical protonation of N2 and N adatoms on cuboctahedral Mo13 nanoparticles. Pathways for electrochemical ammonia production via direct protonation of N adatoms and N2 admolecules with an onset potential as low as -0.5 V and generally lower than -0.8 V on both a nitrogen...

  17. Phenolic compounds and related enzymes as determinants of sorghum for food use

    NARCIS (Netherlands)

    Dicko, M.H.; Gruppen, H.; Traore, A.S.; Voragen, A.G.J.; Berkel, van W.J.H.

    2006-01-01

    Phenolic compounds and related enzymes such as phenol biosynthesizing enzymes (phenylalanine ammonia lyase) and phenol catabolizing enzymes (polyphenol oxidase and peroxidase) are determinants for sorghum utilization as human food because they influence product properties during and after sorghum pr

  18. Induction of trap formation in nematode-trapping fungi by bacteria-released ammonia.

    Science.gov (United States)

    Su, H N; Xu, Y Y; Wang, X; Zhang, K Q; Li, G H

    2016-04-01

    A total of 11 bacterial strains were assayed for bacteria-induced trap formation in the nematode-trapping fungus Arthrobotrys oligospora YMF1·01883 with two-compartmented Petri dish. These strains were identified on the basis of their 16S rRNA gene sequences. Volatile organic compounds (VOCs) of eight isolates were extracted using solid-phase micro-extraction (SPME) and their structures were identified based on gas chromatography-mass spectrometry (GC-MS). At the same time, all isolates were used for quantitative measurement of ammonia by the indophenol blue method. The effects of pure commercial compounds on inducement of trap formation in A. oligospora were tested. Taken together, results demonstrated that the predominant bacterial volatile compound inducing trap formation was ammonia. Meanwhile, ammonia also played a role in other nematode-trapping fungi, including Arthrobotrys guizhouensis YMF1·00014, producing adhesive nets; Dactylellina phymatopaga YMF1·01474, producing adhesive knobs; Dactylellina cionopaga YMF1·01472, producing adhesive columns and Drechslerella brochopaga YMF1·01829, producing constricting rings.

  19. Ammonia effect on hydrogenotrophic methanogens and syntrophic acetate oxidizing bacteria

    DEFF Research Database (Denmark)

    Wang, Han; Fotidis, Ioannis; Angelidaki, Irini

    2015-01-01

    Ammonia-rich substrates can cause inhibition on anaerobic digestion process. Syntrophic acetate oxidizing bacteria (SAOB) and hydrogenotrophic methanogens are important for the ammonia inhibitory mechanism on anaerobic digestion. The roles and interactions of SAOB and hydrogenotrophic methanogens...

  20. Study of Ammonia Emissions in a Ventilated Pig Pen

    DEFF Research Database (Denmark)

    Rong, Li

    Pig productions cause a wide emission of odors, such as ammonia (NH3), hydrogen sulfide (H2S), and methane (CH4). Ammonia is one of the most important emissions for evaluating the air quality either in animal buildings or atmospheric environment. In studies of ammonia emission from animal buildings...... solution temperatures. The results show that the diffusive ceiling ventilation system can provide a relative low velocity in the pig pen and decrease ammonia emissions from the pig pen, but this ventilation system causes high ammonia concentration distribution in the animal occupied zone. Further, our...... reported in literature, little effort has been made to investigate the accuracy of current Henry’s law constant for modeling ammonia mass transfer process and study ammonia emissions in a full scale pig pen from fluid dynamics by CFD simulations. This will be the main objectives of this study. The ammonia...

  1. Modelling of ammonia emissions from dairy cow houses

    OpenAIRE

    Monteny, G.J.

    2000-01-01

    Dairy cow husbandry contributes to environmental acidification through the emission of ammonia. In-depth knowledge on the processes and variable factors that play a role in the emission of ammonia from dairy cow houses benefits the production of emission data, the development of low emission housing systems, and evaluation of emission levels in a farming system approach. A mechanistic simulation model for the ammonia emission from dairy cow houses was developed to facilitate this.An ammonia p...

  2. Detection of Ammonia in Liquids Using Millimeter Wave Spectroscopy

    Directory of Open Access Journals (Sweden)

    Hilmi Ozturk

    2012-01-01

    Full Text Available Detection of ammonia plays a vital role for counter-bioterrorism applications. Using millimeter wave absorption measurements, ammonia dissolved in water solution is analyzed and compared to water-only solution. The inversion of ammonia molecule results in split rotational spectral lines and transitions of these lines can be detected. Two-port measurements were carried out with vector network analyzer and measurements revealed that ammonia presence can be identified, especially between 30–35 GHz.

  3. Comparison of ammonia emissions determined using different sampling methods

    Science.gov (United States)

    Dynamic, flow-through flux chambers are sometimes used to estimate ammonia emissions from livestock operations; however, ammonia emissions from the surfaces are affected by many factors which can be affected by the chamber. Ammonia emissions estimated using environmental flow-through chambers may be...

  4. The Ammonia Smoke Fountain: An Interesting Thermodynamic Adventure.

    Science.gov (United States)

    Alexander, M. Dale

    1999-01-01

    Describes a new demonstration that uses an apparatus like the ammonia-fountain apparatus but with modifications designed to produce ammonium-chloride smoke. This demonstration is easy to perform, interesting to observe, and allows demonstration of the solubility of ammonia in water, the basic nature of ammonia, the acidic nature of hydrogen…

  5. Cerebral ammonia uptake and accumulation during prolonged exercise in humans

    DEFF Research Database (Denmark)

    Nybo, Lars; Dalsgaard, Mads K.; Steensberg, Adam

    2005-01-01

    We evaluated whether peripheral ammonia production during prolonged exercise enhances the uptake and subsequent accumulation of ammonia within the brain. Two studies determined the cerebral uptake of ammonia (arterial and jugular venous blood sampling combined with Kety-Schmidt-determined cerebra...

  6. Werkwijze voor het behandelen van ammonia-houdend afvalwater

    NARCIS (Netherlands)

    Loosdrecht, M.C.M.; Jetten, M.S.M.

    1998-01-01

    Treatment of ammonia-comprising waste water comprises: (a) subjecting the waste water to a nitrification treatment using a nitrifying microorganism and adding oxygen, to give a solution comprising an oxidation product of ammonia, and (b) converting the oxidation product of ammonia into nitrogen usin

  7. Treatment of nickel-ammonia complex ion-containing ammonia nitrogen wastewater

    Institute of Scientific and Technical Information of China (English)

    MIN Xiao-bo; ZHOU Min; CHAI Li-yuan; WANG Yun-yan; SHU Yu-de

    2009-01-01

    Air stripping was adopted to treat nickel ammonia complex ion-containing wastewater in order to remove nickel and ammonia simultaneously in one technological process. The relationship among pH, the concentration of nickel ammonia complex ion and total ammonia concentration was analyzed theoretically. Influence of pH value, water temperature, airflow rate and time on air stripping was studied in detail by static experiment in laboratory. The results show that at pH 11, temperature of 60 ℃ and airflow rate of 0.12 m~3/h, NH_3 and Ni~(2+) concentrations remained in wastewater are less than 2 and 0.2 mg/L, respectively, after blowing for 75 min, which reaches the standard of the state discharge. When the tail gas is absorbed by 0.5 mol/L H_2SO_4 in order to avoid the secondary pollution, the absorption rate can achieve 70%.

  8. Ammonia tolerant enriched methanogenic cultures as bioaugmentation inocula to alleviate ammonia inhibition in continuous anaerobic reactors

    DEFF Research Database (Denmark)

    Fotidis, Ioannis; Wang, Han; Angelidaki, Irini

    tolerant methanogenic culture as potential bioaugmentation inoculum in a continuous stirred tank reactor (CSTR) operating under “inhibited steady-state”, triggered by high ammonia levels (5 g NH4+-N L-1). The results of the current study established for the first time that bioaugmentation of an enriched...... ammonia tolerant methanogen in a CSTR reactor could completely alleviate the ammonia inhibitory effect. Furthermore, it was found that bioaugmentation with the enriched culture resulted in 25% higher methane production compared to when the bioaugmentation was achieved with pure methanogenic strains....... The bioaugmentation was performed without pausing the continuous operation of the CSTR reactor and without excluding the ammonia-rich substrate from the feedstock. Thus, bioaugmentation with mixed methanogenic cultures could potentially support the development of an efficient and cost-effective biomethanation process...

  9. Adsorption of Ammonia on Regenerable Carbon Sorbents

    Science.gov (United States)

    Wójtowicz, Marek A.; Cosgrove, Jesph E.; Serio, Michael A..; Wilburn, Monique

    2015-01-01

    Results are presented on the development of reversible sorbents for the combined carbon dioxide, moisture, and trace-contaminant (TC) removal for use in Extravehicular Activities (EVAs), and more specifically in the Primary Life Support System (PLSS). The currently available life support systems use separate units for carbon dioxide, trace contaminants, and moisture control, and the long-term objective is to replace the above three modules with a single one. Data on sorption and desorption of ammonia, which is a major TC of concern, are presented in this paper. The current TC-control technology involves the use of a packed bed of acid-impregnated granular charcoal, which is non-regenerable, and the carbon-based sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. In this study, several carbon sorbents were fabricated and tested for ammonia sorption. Ammonia-sorption capacity was related to carbon pore structure characteristics, and the temperature of oxidative carbon-surface treatment was optimized for enhanced ammonia-sorption performance.

  10. USDA-EPA Collaborative Ammonia Research

    Science.gov (United States)

    In 2014, a work group was formed between USDA and EPA to facilitate information exchange on ammonia emissions from agriculture, air quality impacts and emission mitigation options and to identify opportunities for collaboration. This document provides background on the work grou...

  11. Ammonia synthesis from first principles calculations

    DEFF Research Database (Denmark)

    Honkala, Johanna Karoliina; Hellman, Anders; Remediakis, Ioannis

    2005-01-01

    The rate of ammonia synthesis over a nanoparticle ruthenium catalyst can be calculated directly on the basis of a quantum chemical treatment of the problem using density functional theory. We compared the results to measured rates over a ruthenium catalyst supported on magnesium aluminum spinet...

  12. Diversity and abundance of ammonia-oxidizing

    NARCIS (Netherlands)

    Cardoso, J.F.M.F.; van Bleijswijk, J.D.L.; Witte, H.; van Duyl, F.C.

    2013-01-01

    We analysed the diversity and abundance of ammonia-oxidizing Archaea (AOA) and Bacteria (AOB) in the shallow warm-water sponge Halisarca caerulea and the deep cold-water sponges Higginsia thielei and Nodastrella nodastrella. The abundance of AOA and AOB was analysed using catalyzed reporter depositi

  13. Radiation Chemistry in Ammonia-Water Ices

    Science.gov (United States)

    Loeffler, M. J.; Raut, U.; Baragiola, R. A.

    2010-01-01

    We studied the effects of 100 keV proton irradiation on films of ammonia-water mixtures between 20 and 120 K. Irradiation destroys ammonia, leading to the formation and trapping of H2, N2 NO, and N2O, the formation of cavities containing radiolytic gases, and ejection of molecules by sputtering. Using infrared spectroscopy, we show that at all temperatures the destruction of ammonia is substantial, but at higher temperatures (120 K), it is nearly complete (approximately 97% destroyed) after a fluence of 10(exp 16) ions per square centimeter. Using mass spectroscopy and microbalance gravimetry, we measure the sputtering yield of our sample and the main components of the sputtered flux. We find that the sputtering yield depends on fluence. At low temperatures, the yield is very low initially and increases quadratically with fluence, while at 120 K the yield is constant and higher initially. The increase in the sputtering yield with fluence is explained by the formation and trapping of the ammonia decay products, N2 and H2 which are seen to be ejected from the ice at all temperatures.

  14. Footprints on Ammonia Concentrations from Environmental Regulations

    DEFF Research Database (Denmark)

    Skjøth, Carsten Ambelas; Ellermann, Thomas; Hertel, Ole

    2008-01-01

    Releases of ammonia (NH3) to the atmosphere contribute significantly to the desposition of nitrogen to both terrestrial and aquatic ecosystems. This is the background for the national NH3 emission ceilings in Europe. However, in some countries the national legislation aims not only to meet theese...

  15. Fiber Optic Detection of Ammonia Gas

    Directory of Open Access Journals (Sweden)

    L. Kalvoda

    2006-01-01

    Full Text Available Bathochromic shifts accompanying the formation of several bivalent metallic complexes containing 5-(4’-dimethylaminophenylimino quinolin-8-one (L1, and 7-chlore-5(4’-diethylamino-2-methylphenylimino quinolin-8-one (L2 ligands in ethanol solutions were evaluated by VIS-NIR spectroscopy. The [L1-Cu-L1] sulphide complex was selected as a reagent for further tests on optical fibres. Samples of multimode siloxane-clad fused-silica fibre were sensitized by diffusing an ethanol/chloroform solution of the dye into the cladding polymer, and tested by VIS-NIR optical spectroscopy (12 cm long fibre sections, and optical time domain reflectometry (OTDR; 20 ns laser pulses, wavelength 850 nm, 120 m long fibre sensitized within the interval 104–110 m. A well-resolved absorption band of the reagent could be identified in the absorption spectra of the fibres. After exposure to dry ammonia/nitrogen gas with increasing ammonia concentration (0–4000 ppm, the short fibre samples showed subsequent decay of NIR optical absorption; saturation was observed for higher ammonia levels. The concentration resolution r ? 50 ppm and forward response time t90 ? 30 sec were obtained within the interval 0–1000 ppm. The OTDR courses showed an enhancement of the back-scattered light intensity coming from the sensitized region after diffusion of the initial reagent, and decay after exposure to concentrated ammonia/nitrogen gas (10000 ppm.

  16. Selective catalytic oxidation of ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Leppaelahti, J.; Koljonen, T. [VTT Energy, Espoo (Finland)

    1996-12-31

    In the combustion of fossil fuels, the principal source of nitrogen oxides is nitrogen bound in the fuel structure. In gasification, a large part of fuel nitrogen forms NH{sub 3}, which may form nitrogen oxides during gas combustion. If NH{sub 3} and other nitrogen species could be removed from hot gas, the NO emission could be considerably reduced. However, relatively little attention has been paid to finding new means of removing nitrogen compounds from the hot gasification gas. The possibility of selectively oxidizing NH{sub 3} to N{sub 2} in the hot gasification has been studied at VTT Energy. The largest NH{sub 3} reductions have been achieved by catalytic oxidation on aluminium oxides. (author) (4 refs.)

  17. Study of an ammonia-based wet scrubbing process in a continuous flow system

    Energy Technology Data Exchange (ETDEWEB)

    Resnik, Kevin P.; Pennline, Henry W.

    2013-03-01

    A continuous gas and liquid flow, regenerative scrubbing process for CO{sub 2} capture was demonstrated at the bench-scale level. An aqueous ammonia-based solution captures CO{sub 2} from simulated flue gas in an absorber and releases a nearly pure stream of CO{sub 2} in the regenerator. After the regeneration, the solution of ammonium compounds is recycled to the absorber. The design of a continuous flow unit was based on earlier exploratory results from a semi-batch reactor, where a CO{sub 2} and N{sub 2} simulated flue gas mixture flowed through a well-mixed batch of ammonia-based solution. During the semi-batch tests, the solution was cycled between absorption and regeneration steps to measure the carrying capacity of the solution at various initial ammonia concentrations and temperatures. Consequentially, a series of tests were conducted on the continuous unit to observe the effect of various parameters on CO{sub 2} removal efficiency and regenerator effectiveness within the flow system. The parameters that were studied included absorber temperature, regenerator temperature, initial NH{sub 3} concentration, simulated flue gas flow rate, liquid solvent inventory in the flow system, and height of the packed-bed absorber. From this testing and subsequent testing, ammonia losses from both the absorption and regeneration steps were quantified, and attempts were made to maintain steady state during operations. Implications of experimental results with respect to process design are discussed.

  18. AMMONIA CONCENTRATION IN SALTSTONE HEADSPACE SUMMARY REPORT

    Energy Technology Data Exchange (ETDEWEB)

    Zamecnik, J; Alex Cozzi, A

    2008-09-26

    The Saltstone Facility Documented Safety Analysis (DSA) is under revision to accommodate changes in the Composite Lower Flammability Limit (CLFL) from the introduction of Isopar into Tank 50. Saltstone samples were prepared with an 'MCU' type salt solution spiked with ammonia. The ammonia released from the saltstone was captured and analyzed. The ammonia concentration found in the headspace of samples maintained at 95 C and 1 atm was, to 95% confidence, less than or equal to 3.9 mg/L. Tank 50 is fed by several influent streams. The salt solution from Tank 50 is pumped to the salt feed tank (SFT) in the Saltstone Production Facility (SPF). The premix materials cement, slag and fly ash are blended together prior to transfer to the grout mixer. The premix is fed to the grout mixer in the SPF and the salt solution is incorporated into the premix in the grout mixer, yielding saltstone slurry. The saltstone slurry drops into a hopper and then is pumped to the vault. The Saltstone Facility Documented Safety Analysis (DSA) is under revision to accommodate changes in the Composite Lower Flammability Limit (CLFL) from the introduction of Isopar{reg_sign} L into Tank 50. Waste Solidification-Engineering requested that the Savannah River National Laboratory (SRNL) perform testing to characterize the release of ammonia in curing saltstone at 95 C. The test temperature represents the maximum allowable temperature in the Saltstone Disposal Facility (SDF). Ammonia may be present in the salt solution and premix materials, or may be produced by chemical reactions when the premix and salt solution are combined. A final report (SRNS-STI-2008-00120, Rev. 0) will be issued that will cover in more depth the information presented in this report.

  19. Ammonia downstream from HH 80 North

    Science.gov (United States)

    Girart, Jose M.; Rodriguez, Luis F.; Anglada, Guillem; Estalella, Robert; Torrelles, Jose, M.; Marti, Josep; Pena, Miriam; Ayala, Sandra; Curiel, Salvador; Noriega-Crespo, Alberto

    1994-01-01

    HH 80-81 are two optically visible Herbig-Haro (HH) objects located about 5 minutes south of their exciting source IRAS 18162-2048. Displaced symmetrically to the north of this luminous IRAS source, a possible HH counterpart was recently detected as a radio continuum source with the very large array (VLA). This radio source, HH 80 North, has been proposed to be a member of the Herbig-Haro class since its centimeter flux density, angular size, spectral index, and morphology are all similar to those of HH 80. However, no object has been detected at optical wavelengths at the position of HH 80 North, possibly because of high extinction, and the confirmation of the radio continuum source as an HH object has not been possible. In the prototypical Herbig-Haro objects HH 1 and 2, ammonia emission has been detected downstream of the flow in both objects. This detection has been intepreted as a result of an enhancement in the ammonia emission produced by the radiation field of the shock associated with the HH object. In this Letter we report the detection of the (1,1) and (2,2) inversion transitions of ammonia downstream HH 80 North. This detection gives strong suppport to the interpretation of HH 80 North as a heavily obscured HH object. In addition, we suggest that ammonia emission may be a tracer of embedded Herbig-Haro objects in other regions of star formation. A 60 micrometer IRAS source could be associated with HH 80 North and with the ammonia condensation. A tentative explanation for the far-infrared emission as arising in dust heated by their optical and UV radiation of the HH object is presented.

  20. Ammonia and ammonium hydroxide sensors for ammonia/water absorption machines: Literature review and data compilation

    Science.gov (United States)

    Anheier, N. C., Jr.; McDonald, C. E.; Cuta, J. M.; Cuta, F. M.; Olsen, K. B.

    1995-05-01

    This report describes an evaluation of various sensing techniques for determining the ammonia concentration in the working fluid of ammonia/water absorption cycle systems. The purpose was to determine if any existing sensor technology or instrumentation could provide an accurate, reliable, and cost-effective continuous measure of ammonia concentration in water. The resulting information will be used for design optimization and cycle control in an ammonia-absorption heat pump. Pacific Northwest Laboratory (PNL) researchers evaluated each sensing technology against a set of general requirements characterizing the potential operating conditions within the absorption cycle. The criteria included the physical constraints for in situ operation, sensor characteristics, and sensor application. PNL performed an extensive literature search, which uncovered several promising sensing technologies that might be applicable to this problem. Sixty-two references were investigated, and 33 commercial vendors were identified as having ammonia sensors. The technologies for ammonia sensing are acoustic wave, refractive index, electrode, thermal, ion-selective field-effect transistor (ISFET), electrical conductivity, pH/colormetric, and optical absorption. Based on information acquired in the literature search, PNL recommends that follow-on activities focus on ISFET devices and a fiber optic evanescent sensor with a colormetric indicator. The ISFET and fiber optic evanescent sensor are inherently microminiature and capable of in situ measurements. Further, both techniques have been demonstrated selective to the ammonium ion (NH4(+)). The primary issue remaining is how to make the sensors sufficiently corrosion-resistant to be useful in practice.

  1. Ammonia and ammonium hydroxide sensors for ammonia/water absorption machines: Literature review and data compilation

    Energy Technology Data Exchange (ETDEWEB)

    Anheier, N.C. Jr.; McDonald, C.E.; Cuta, J.M.; Cuta, F.M.; Olsen, K.B.

    1995-05-01

    This report describes an evaluation of various sensing techniques for determining the ammonia concentration in the working fluid of ammonia/water absorption cycle systems. The purpose of this work was to determine if any existing sensor technology or instrumentation could provide an accurate, reliable, and cost-effective continuous measure of ammonia concentration in water. The resulting information will be used for design optimization and cycle control in an ammonia-absorption heat pump. PNL researchers evaluated each sensing technology against a set of general requirements characterizing the potential operating conditions within the absorption cycle. The criteria included the physical constraints for in situ operation, sensor characteristics, and sensor application. PNL performed an extensive literature search, which uncovered several promising sensing technologies that might be applicable to this problem. Sixty-two references were investigated, and 33 commercial vendors were identified as having ammonia sensors. The technologies for ammonia sensing are acoustic wave, refractive index, electrode, thermal, ion-selective field-effect transistor (ISFET), electrical conductivity, pH/colormetric, and optical absorption. Based on information acquired in the literature search, PNL recommends that follow-on activities focus on ISFET devices and a fiber optic evanescent sensor with a colormetric indicator. The ISFET and fiber optic evanescent sensor are inherently microminiature and capable of in situ measurements. Further, both techniques have been demonstrated selective to the ammonium ion (NH{sub 4}{sup +}). The primary issue remaining is how to make the sensors sufficiently corrosion-resistant to be useful in practice.

  2. Study of Hydrogen Supply System with Ammonia Fuel

    Science.gov (United States)

    Saika, Takashi; Nakamura, Mitsuhiro; Nohara, Tetsuo; Ishimatsu, Shinji

    Carbon-free fuel is effective in preventing global warming. Hydrogen has no carbon and can be made also from nuclear energy or reproducible energies other than fossil fuels. However, hydrogen lacks portability because of its difficulty in liquefying, but ammonia can easily be liquefied at a room temperature and dissociated into high-content hydrogen and nitrogen using a suitable catalyst. An ammonia dissociation system for fuel cells is proposed in this paper. The residual ammonia by 13ppm or more in the dissociated gas (H2+ N2) causes a decrease in the output of fuel cells. To separate residual ammonia, it should be sent to an ammonia separator and then to an ammonia distiller. In the experiment, the authors examine the concentrations of ammonia after dissociation at various temperatures, pressures and space velocities. The ammonia separator uses the fact that ammonia dissolves well in water. Then the ammonia water is distilled in the distiller. Thereby, the authors have proposed an ammonia circulation system that is a clean energy system.

  3. Establishing relative sensitivities of various toxicity testing organisms to ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Karle, L.M.; Mayhew, H.L.; Barrows, M.E.; Karls, R.K. [Battelle/Marine Sciences Lab., Sequim, WA (United States)

    1994-12-31

    The toxicity of ammonia to various organisms was examined to develop a baseline for mortality in several commonly used testing species. This baseline data will assist in choosing the proper test species and in interpreting results as they pertain to ammonia. Responses for two juvenile fish species, three marine amphipods, and two species of mysid shrimp were compared for their sensitivity to levels of ammonia. All mortality caused by ammonia in the bottom-dwelling Citharichthys stigmaeus occurred within 24 h of exposure, whereas mortality in the silverside, Menidia beryllina, occurred over the entire 96-h test duration. Responses to ammonia varied among the amphipods Rhepoxynius abronius, Ampelisca abdita, and Eohaustorius estuarius. R. abronius and A. abdita showed similar sensitivity to ammonia at lower concentrations; A. abdita appeared more sensitive than R. abronius at levels above 40 mg/L. Concentrations of ammonia required to produce significant mortality in the amphipod E. estuarius were far higher than the other species examined (> 100 mg/L NH{sub 3}). A comparison of ammonia toxicity with two commonly used invertebrates, Holmesimysis sculpts and Mysidopsis bahia, suggest that these two species of mysid have similar sensitivities to ammonia. Further studies with ammonia that examine sensitivity of different organisms should be conducted to assist regulatory and environmental agencies in determining appropriate test species and in interpreting toxicological results as they may be affected by levels of ammonia.

  4. Effects of Glycine, Water, Ammonia, and Ammonium Bicarbonate on the Oligomerization of Methionine

    Science.gov (United States)

    Huang, Rui; Furukawa, Yoshihiro; Otake, Tsubasa; Kakegawa, Takeshi

    2016-09-01

    The abiotic oligomerization of amino acids may have created primordial, protein-like biological catalysts on the early Earth. Previous studies have proposed and evaluated the potential of diagenesis for the amino acid oligomerization, simulating the formation of peptides that include glycine, alanine, and valine, separately. However, whether such conditions can promote the formation of peptides composed of multiple amino acids remains unclear. Furthermore, the chemistry of pore water in sediments should affect the oligomerization and degradation of amino acids and oligomers, but these effects have not been studied extensively. In this study, we investigated the effects of water, ammonia, ammonium bicarbonate, pH, and glycine on the oligomerization and degradation of methionine under high pressure (150 MPa) and high temperature conditions (175 °C) for 96 h. Methionine is more difficult to oligomerize than glycine and methionine dimer was formed in the incubation of dry powder of methionine. Methionine oligomers as long as trimers, as well as methionylglycine and glycylmethionine, were formed under every condition with these additional compounds. Among the compounds tested, the oligomerization reaction rate was accelerated by the presence of water and by an increase in pH. Ammonia also increased the oligomerization rate but consumed methionine by side reactions and resulted in the rapid degradation of methionine and its peptides. Similarly, glycine accelerated the oligomerization rate of methionine and the degradation of methionine, producing water, ammonia, and bicarbonate through its decomposition. With Gly, heterogeneous dimers (methionylglycine and glycylmethionine) were formed in greater amounts than with other additional compounds although smaller amount of these heterogeneous dimers were formed with other additional compounds. These results suggest that accelerated reaction rates induced by water and co-existing reactive compounds promote the oligomerization

  5. Spin-state chemistry of deuterated ammonia

    Science.gov (United States)

    Sipilä, O.; Harju, J.; Caselli, P.; Schlemmer, S.

    2015-09-01

    Aims: We aim to develop a chemical model that contains a consistent description of spin-state chemistry in reactions involving chemical species with multiple deuterons. We apply the model to the specific case of deuterated ammonia, to derive values for the various spin-state ratios. Methods: We applied symmetry rules in the context of the complete scrambling assumption to calculate branching ratio tables for reactions between chemical species that include multiple protons and/or deuterons. New reaction sets for both gas-phase and grain-surface chemistry were generated using an automated routine that forms all possible spin-state variants of any given reaction with up to six H/D atoms, using the predetermined branching ratios. Both a single-point and a modified Bonnor-Ebert model were considered to study the density and temperature dependence of ammonia and its isotopologs, and the associated spin-state ratios. Results: We find that the spin-state ratios of the ammonia isotopologs are, at late times, very different from their statistical values. The ratios are rather insensitive to variations in the density, but present strong temperature dependence. We derive high peak values (~0.1) for the deuterium fraction in ammonia, in agreement with previous (gas-phase) models. The deuterium fractionation is strongest at high density, corresponding to a high degree of depletion, and also presents temperature dependence. We find that in the temperature range 5 K to 20 K, the deuterium fractionation peaks at ~15 K, while most of the ortho/para (and meta/para for ND3) ratios present a minimum at 10 K (ortho/para NH2D has instead a maximum at this temperature). Conclusions: Owing to the density and temperature dependence found in the abundances and spin-state ratios of ammonia and its isotopologs, it is evident that observations of ammonia and its deuterated forms can provide important constraints on the physical structure of molecular clouds. Appendix A is available in

  6. EFFECTS OF AMMONIA LOADING ON PORCELLIO SCABER: GLUTAMINE AND GLUTAMATE SYNTHESIS, AMMONIA EXCRETION AND TOXICITY

    Science.gov (United States)

    Wright; Donnell; Reichert

    1994-03-01

    The effects of ammonia loading in the terrestrial isopod Porcellio scaber were studied by exposing animals to atmospheres of high PNH3. Isopods show a remarkable tolerance of elevated ambient PNH3, with an LD50 of 89 Pa for a 7-day exposure. However, haemolymph total ammonia concentrations generally remained below 5 mmol l-1 (PNH3=0.37 Pa) over the range of ambient ammonia levels used (6.6­165 Pa). Following a 7-day loading period, whole-animal glutamine (Gln) and glutamate (Glu) levels increased in direct proportion to ambient PNH3, reaching values of 35 µmol g-1 fresh mass for glutamine and 12 µmol g-1 fresh mass for glutamate in 99 Pa PNH3; these correspond to control levels of 7.5 µmol g-1 fresh mass and 5.9 µmol g-1 fresh mass, respectively. Following transfer to ammonia-free chambers, NH3 excretion rates were augmented five- to sixfold relative to non-loaded controls. Ammonia volatilization subsequently declined, approaching control levels after 8­9 days. Levels of Gln and Glu showed a concomitant decline to 13.7 µmol g-1 fresh mass and 9.2 µmol g-1 fresh mass, respectively. The results suggest that these amino acids function in ammonia sequestration and, hence, detoxification. Calculations indicate that mobilization of amino groups by deamination of accumulated Gln and Glu could explain 35 % of the increased ammonia production. Implications of NH3 volatilization for acid­base balance are discussed.

  7. Reactive uptake of ammonia to secondary organic aerosols: kinetics of organonitrogen formation

    Science.gov (United States)

    Liu, Y.; Liggio, J.; Staebler, R.; Li, S.-M.

    2015-12-01

    As a class of brown carbon, organonitrogen compounds originating from the heterogeneous uptake of NH3 by secondary organic aerosol (SOA) have received significant attention recently. In the current work, particulate organonitrogen formation during the ozonolysis of α-pinene and the OH oxidation of m-xylene in the presence of ammonia (34-125 ppb) was studied in a smog chamber equipped with a high resolution time-of-flight aerosol mass spectrometer and a quantum cascade laser instrument. A large diversity of nitrogen-containing organic (NOC) fragments was observed which were consistent with the reactions between ammonia and carbonyl-containing SOA. Ammonia uptake coefficients onto SOA which led to organonitrogen compounds were reported for the first time, and were in the range of ∼ 10-3-10-2, decreasing significantly to concentration, indicating that heterogeneous reactions were responsible for the observed NOC mass, possibly limited by liquid phase diffusion. Under these conditions, the data also indicate that the formation of NOC can compete kinetically with inorganic acid neutralization. The formation of NOC in this study suggests that a significant portion of the ambient particle associated N may be derived from NH3 heterogeneous reactions with SOA. NOC from such a mechanism may be an important and unaccounted for source of PM associated nitrogen. This mechanism may also contribute to the medium or long-range transport and wet/dry deposition of atmospheric nitrogen.

  8. Multi-component removal in flue gas by aqua ammonia

    Science.gov (United States)

    Yeh, James T.; Pennline, Henry W.

    2007-08-14

    A new method for the removal of environmental compounds from gaseous streams, in particular, flue gas streams. The new method involves first oxidizing some or all of the acid anhydrides contained in the gas stream such as sulfur dioxide (SO.sub.2) and nitric oxide (NO) and nitrous oxide (N.sub.2O) to sulfur trioxide (SO.sub.3) and nitrogen dioxide (NO.sub.2). The gas stream is subsequently treated with aqua ammonia or ammonium hydroxide which captures the compounds via chemical absorption through acid-base or neutralization reactions. The products of the reactions can be collected as slurries, dewatered, and dried for use as fertilizers, or once the slurries have been dewatered, used directly as fertilizers. The ammonium hydroxide can be regenerated and recycled for use via thermal decomposition of ammonium bicarbonate, one of the products formed. There are alternative embodiments which entail stoichiometric scrubbing of nitrogen oxides and sulfur oxides with subsequent separate scrubbing of carbon dioxide.

  9. Genomic Characterization of Phenylalanine Ammonia Lyase Gene in Buckwheat.

    Directory of Open Access Journals (Sweden)

    Karthikeyan Thiyagarajan

    Full Text Available Phenylalanine Ammonia Lyase (PAL gene which plays a key role in bio-synthesis of medicinally important compounds, Rutin/quercetin was sequence characterized for its efficient genomics application. These compounds possessing anti-diabetic and anti-cancer properties and are predominantly produced by Fagopyrum spp. In the present study, PAL gene was sequenced from three Fagopyrum spp. (F. tataricum, F. esculentum and F. dibotrys and showed the presence of three SNPs and four insertion/deletions at intra and inter specific level. Among them, the potential SNP (position 949th bp G>C with Parsimony Informative Site was selected and successfully utilised to individuate the zygosity/allelic variation of 16 F. tataricum varieties. Insertion mutations were identified in coding region, which resulted the change of a stretch of 39 amino acids on the putative protein. Our Study revealed that autogamous species (F. tataricum has lower frequency of observed SNPs as compared to allogamous species (F. dibotrys and F. esculentum. The identified SNPs in F. tataricum didn't result to amino acid change, while in other two species it caused both conservative and non-conservative variations. Consistent pattern of SNPs across the species revealed their phylogenetic importance. We found two groups of F. tataricum and one of them was closely related with F. dibotrys. Sequence characterization information of PAL gene reported in present investigation can be utilized in genetic improvement of buckwheat in reference to its medicinal value.

  10. Operation summary of ammonia synthesis ammonia storage safety%合成氨氨库安全运行总结

    Institute of Scientific and Technical Information of China (English)

    周荷珍; 张志翠

    2014-01-01

    介绍了氨对人体健康的危害及急救措施、氨罐的操作、汽车氨罐卸氨的原理及具体操作、氨吸收塔的操作,指出只有对氨库实行科学管理和精心操作,才能保证氨库的长期安全稳定运行。%The paper introduces damage from ammonia on human health and emergency measures, ammonia tank operation, the principle of car unloading ammonia ammonia tank and the specific operation, ammonia absorption tower operation, points out that only the ammonia base of scientific management and careful operation, in order to ensure the long-term safe and stable operation of ammonia storage.

  11. Modelling of Ammonia Heat Pump Desuperheaters

    DEFF Research Database (Denmark)

    Christensen, Stefan Wuust; Elmegaard, Brian; Markussen, Wiebke Brix

    2015-01-01

    This paper presents a study of modelling desuperheating in ammonia heat pumps. Focus is on the temperature profile of the superheated refrigerant. Typically, the surface area of a heat exchanger is estimated using the Log Mean Temperature Difference (LMTD) method. The assumption of this method...... is that the specific heat is constant throughout the temperature glide of the refrigerant in the heat exchanger. However, considering ammonia as refrigerant, the LMTD method does not give accurate results due to significant variations of the specific heat. By comparing the actual temperature profiles from a one....... The area of the heat exchanger can be increased or the condensation temperature can be raised to achieve the same temperature difference for the discretized model as for the LMTD. This would affect the compressor work, hence the COP of the system. Furthermore, for higher condenser pressure, and thus higher...

  12. Ammonia volatilization from sows on grassland

    Science.gov (United States)

    Sommer, S. G.; Søgaard, H. T.; Møller, H. B.; Morsing, S.

    According to regulations, sows with piglets on organic farms must graze on pastures. Volatilization of ammonia (NH 3) from urine patches may represent a significant source of nitrogen (N) loss from these farms. Inputs of N are low on organic farms and losses may reduce crop production. This study examined spatial variations in NH 3 volatilization using a movable dynamic chamber, and the pH and total ammoniacal nitrogen (TAN) content in the topsoil of pastures with grazing sows was measured during five periods between June 1998 and May 1999. Gross NH 3 volatilization from the pastures was also measured with an atmospheric mass balance technique during seven periods from September 1997 until June 1999. The dynamic chamber study showed a high variation in NH 3 volatilization because of the distribution of urine; losses were between 0 and 2.8 g NH 3-N m -2 day -1. Volatilization was highest near the feeding area and the huts, where the sows tended to urinate. Ammonia volatilization rate was linearly related to the product of NH 3 concentration in the boundary layer and wind speed. The NH 3 in the boundary layer was in equilibrium with NH 3 in soil solution. Gross NH 3 volatilization was in the range 0.07-2.1 kg NH 3-N ha -1 day -1 from a pasture with 24 sows ha -1. Ammonia volatilization was related to the amount of feed given to the sows, incident solar radiation and air temperature during measuring periods, and also to temperature, incident solar radiation and rain 1-2 days before measurements. Annual ammonia loss was 4.8 kg NH 3-N sow -1.

  13. Diverse microbial species survive high ammonia concentrations

    Science.gov (United States)

    Kelly, Laura C.; Cockell, Charles S.; Summers, Stephen

    2012-04-01

    Planetary protection regulations are in place to control the contamination of planets and moons with terrestrial micro-organisms in order to avoid jeopardizing future scientific investigations relating to the search for life. One environmental chemical factor of relevance in extraterrestrial environments, specifically in the moons of the outer solar system, is ammonia (NH3). Ammonia is known to be highly toxic to micro-organisms and may disrupt proton motive force, interfere with cellular redox reactions or cause an increase of cell pH. To test the survival potential of terrestrial micro-organisms exposed to such cold, ammonia-rich environments, and to judge whether current planetary protection regulations are sufficient, soil samples were exposed to concentrations of NH3 from 5 to 35% (v/v) at -80°C and room temperature for periods up to 11 months. Following exposure to 35% NH3, diverse spore-forming taxa survived, including representatives of the Firmicutes (Bacillus, Sporosarcina, Viridibacillus, Paenibacillus, Staphylococcus and Brevibacillus) and Actinobacteria (Streptomyces). Non-spore forming organisms also survived, including Proteobacteria (Pseudomonas) and Actinobacteria (Arthrobacter) that are known to have environmentally resistant resting states. Clostridium spp. were isolated from the exposed soil under anaerobic culture. High NH3 was shown to cause a reduction in viability of spores over time, but spore morphology was not visibly altered. In addition to its implications for planetary protection, these data show that a large number of bacteria, potentially including spore-forming pathogens, but also environmentally resistant non-spore-formers, can survive high ammonia concentrations.

  14. Manufacture of Catalyst Systems for Ammonia Conversion

    Institute of Scientific and Technical Information of China (English)

    GAKH S.V.; SAVENKOV D.A.

    2012-01-01

    Platinum catalyst gauzes have been in use since the moment of development of the process of catalyst oxidation of ammonia for production of nitric acid or hydrocyanic acid.Catalyst gauzes are usually made of platinum or its alloys with rhodium and palladium.These precious metals have remarkable properties that make them ideal catalysts for acceleration of the ammonia/oxygen reaction.In 2008,OJSC "SIC ‘Supermetal’" and Umicore AG&Co.KG launched a production line for Pt-alloy-based catalyst systems to be used for ammonia oxidation in the production of weak nitric acid.Catalyst systems consist of a pack of catalyst gauzes and a pack of catchment gauzes,which are made using flat-bed knitting machines and wire-cloth looms.Today,up-to-date catalyst systems MKSpreciseTM are being manufactured,the basic advantages of which are an individual structure of gauzes and composition of the material,which allows to define precisely the position of each gauze in the catalyst pack,a high activity of the catalyst pack,direct catching of platinum and rhodium in the catalyst system,and a reasonable combination of single- and multilayer types of gauzes.This makes it possible to vary the configuration of the catalyst and select an optimum composition of the system to ensure the maximum efficiency of the ammonia oxidation process.We also produce the catchment systems that allow to find the best decision from the economic point view for each individual case.

  15. Electroreduction of N2 to ammonia at ambient conditions on mononitrides of Zr, Nb, Cr, and V – A DFT guide for experiments

    DEFF Research Database (Denmark)

    Abghoui, Younes; Garden, Anna L.; Howalt, Jakob Geelmuyden

    2016-01-01

    with only a -0.5 V overpotential, thereby avoiding decomposition. We suggest that this is a promising step towards the development of a method for synthesizing ammonia cheaply, to prepare high-value-added nitrogenous compounds directly from air, water and electricity at ambient conditions. An additional......A rapid and facile reduction of nitrogen to achieve a sustainable and energy efficient production of ammonia is critical to its use as a hydrogen storage medium, chemical feedstock and especially for manufacturing inorganic fertilizers. For a decentralization of catalytic ammonia production, small...... of molecular nitrogen to ammonia in aqueous media at ambient conditions with only a low applied bias. The most promising catalysts are VN, ZrN, NbN and CrN, which are identified among a range of transition metal nitride surfaces through a comprehensive density functional theory based analysis. All four...

  16. Ammonia biofiltration and community analysis of ammonia-oxidizing bacteria in biofilters.

    Science.gov (United States)

    Jun, Yin; Wenfeng, Xu

    2009-09-01

    Biological removal of ammonia was investigated using compost and sludge as packing materials in laboratory-scale biofilters. The aim of this study is to characterize the composition of ammonia-oxidizing bacteria (AOB) in two biofilters designed to remove ammonia. Experimental tests and measurements included analysis of removal efficiency and metabolic products. The inlet concentration of ammonia applied was 20-100 mg m(-3). Removal efficiencies of BFC and BFS were in the range of 97-99% and 95-99%, respectively. Periodic analysis of the biofilter packing materials showed ammonia was removed from air stream by nitrification and by the improved absorption of NH(3) in the resultant acidity. Nitrate was the dominant product of NH(3) transformation. Changes in the composition of AOB were examined by using nested PCR, denaturing gradient gel electrophoresis (DGGE) and sequencing of DGGE bands. DGGE analysis of biofilter samples revealed that shifts in the community structure of AOB were observed in the experiment; however, the idle phase did not cause the structural shift of AOB. Phylogenetic analysis revealed the population of AOB showed Nitrosospira sp. remains the predominant population in BFC, while Nitrosomonas sp. is the predominant population in BFS.

  17. Determination of Ammonia Oxidizing Bacteria and Nitrate Oxidizing Bacteria in Wastewater and Bioreactors

    Science.gov (United States)

    Francis, Somilez Asya

    2014-01-01

    The process of water purification has many different physical, chemical, and biological processes. One part of the biological process is the task of ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB). Both play critical roles in the treatment of wastewater by oxidizing toxic compounds. The broad term is nitrification, a naturally occurring process that is carried out by AOB and NOB by using oxidation to convert ammonia to nitrite and nitrite to nitrate. To monitor this biological activity, bacterial staining was performed on wastewater contained in inoculum tanks and biofilm samples from bioreactors. Using microscopy and qPCR, the purpose of this experiment was to determine if the population of AOB and NOB in wastewater and membrane bioreactors changed depending on temperature and hibernation conditions to determine the optimal parameters for AOB/NOB culture to effectively clean wastewater.

  18. Spin-state chemistry of deuterated ammonia

    CERN Document Server

    Sipilä, O; Caselli, P; Schlemmer, S

    2015-01-01

    Aims. We aim to develop a chemical model that contains a consistent description of spin-state chemistry in reactions involving chemical species with multiple deuterons. We apply the model to the specific case of deuterated ammonia, to derive values for the various spin-state ratios. Methods. We apply symmetry rules in the complete scrambling assumption to calculate branching ratio tables for reactions between chemical species that include multiple protons and/or deuterons. Reaction sets for both gas-phase and grain-surface chemistry are generated using an automated routine that forms all possible spin-state variants of any given reaction with up to six H/D atoms. Single-point and modified Bonnor-Ebert models are used to study the density and temperature dependence of ammonia and its isotopologs, and the associated spin-state ratios. Results. We find that the spin-state ratios of the ammonia isotopologs are, at late times, very different from their statistical values. The ratios are rather insensitive to varia...

  19. The use of anhydrous ammonia for bioventing

    Energy Technology Data Exchange (ETDEWEB)

    Zytner, R.G.; Hallman, M.; Gimenez, B.F.; Jennings, R.; Leek, K. [Guelph Univ., ON (Canada). Faculty of Graduate Studies

    2002-07-01

    Soils contaminated with hydrocarbons can be effectively treated using bioventing remediation technology, an ideal method for removing residual contamination left by soil vapour extraction (SVE). Bioventing uses low or intermitted air flow rates to produce oxygen-rich conditions in the vadose zone, thereby promoting the formation of micro-organisms that can mineralize the hydrocarbons if enough nutrients are present. There is concern regarding the use of nutrients (the addition of nitrogen) to the subsurface because current applications methods cannot uniformly disperse nitrogen throughout the entire subsurface. Two research studies are being conducted using gasoline contaminated soil to address this concern. The first phase of the study focuses on how to best deliver nitrogen to the subsurface. Injecting anhydrous ammonia into the contaminated surface was one suggestion for stimulating the growth of hydrocarbon degraders. SVE extraction well models indicated this was an effective and safe way to disperse nitrogen. The second phase of the study involved the use of respirometers to compare total petroleum hydrocarbon (TPH) degradation with nitrogen additions in the form of NH{sub 4}Cl or anhydrous ammonia. The respirometers were run for about 1 month after which time it was determined that the use of anhydrous ammonia is an effective method to promote bioventing.

  20. Body composition and energy utilization by steers of diverse genotypes fed a high-concentrate diet during the finishing period: II. Angus, Boran, Brahman, Hereford, and Tuli sires.

    Science.gov (United States)

    Ferrell, C L; Jenkins, T G

    1998-02-01

    Objectives of the study were to determine the influence of Angus (A), Boran (BO), Brahman (BR), Hereford (H), or Tuli (T) sires on body composition, composition of gain, and energy utilization of crossbred steers during the finishing period. Beginning at 300 kg, 96 steers were adjusted to a high-corn diet and individual feeding. Steers were assigned, by sire breed, to be killed as an initial slaughter group or fed either a limited amount or ad libitum for 140 d then killed. Organ weights, carcass traits, and body composition were evaluated. The statistical model included sire breed (S), treatment (Trt), and the S x Trt interaction. Ad libitum feed intake was least for BO- and T-, intermediate for BR- and H-, and greatest for A-sired steers. Rates of weight, fat, and energy gains were similar for A-, H-, and BR-sired steers but less (P .12). Rates of water, fat, and protein gain increased linearly with increased rate of BW gain, but relationships differed (P < .05) among sire breeds. Linear regression analyses indicated energy requirements for maintenance and efficiency of energy use for energy gain differed (P < .05) among sire breeds. Evaluation by nonlinear regression indicated that heat production increased exponentially and energy gain increased asymptotically as feed intake increased above maintenance.

  1. Theoretical approach to the conformational analyses of dithiazinane, thiadiazinane and triazinane, their N-borane adducts and N-H cations

    Science.gov (United States)

    Suárez-Moreno, Galdina V.; Xotlanihua-Flores, Alfonso; Vela, Alberto; Contreras, Rosalinda; Flores-Parra, Angelina

    2016-06-01

    Computational methods were applied to the study of the different nitrogen and chair conformers of [1,3,5]-dithiazinanes, [1,3,5]-thiadiazinanes and [1,3,5]-triazinanes. Optimisation of heterocycles bearing N-H and N-Me were performed by B3LYP density functional and the 6-311++G** basis set methods, and their free energies were correlated. N-Borane adducts and the protonated cations of these heterocycles were also optimized. The relative free energy differences (ΔG) in gas phase of the chair conformers of eighteen heterocycles were calculated. Calculations agree with experimental data and allow to explain the steric and electronic factors that determine the preferred conformations. The distribution of the electronic density and the NBO atomic charges of the optimized structures support the experimental conformational analyses. The bonding and intramolecular interactions were analysed by using critical point search of the electronic density. They were also evaluated by exchange reduced density gradients associated to overlapping, using the PBE functional with the DZUP basis set. Proton-hydride, proton-proton, hydride-hydride, hydride-sulphur, proton-sulphur and hydride-nitrogen stabilising weak interactions were analysed.

  2. Optimization of biomethanation focusing on high ammonia loaded processes

    DEFF Research Database (Denmark)

    Wang, Han

    , could theoretically mitigate the ammonia inhibition problem (Angelidaki et al., 1999). Therefore, the effect of co-digestion of cattle manure with lipids (i.e. glycerol trioleate (GTO)) under high ammonia levels (5 g NH4+-N·L-1) in anaerobic continuous stirred tank (CSTR) reactors (RGTO) was assessed...... and subsequently been converted together with carbon dioxide to methane by hydrogenotrophic methanogens, could potentially be more tolerant to ammonia toxicity. Therefore, the effect of different ammonia levels on this hydrogen assisted biogas upgrading process under different hydrogen partial pressure (0, 0.25, 0.......5 and 1 atm) in anaerobic reactors at both mesophilic and thermophilic temperature was evaluated. When the initial hydrogen partial pressure was 0.5 atm, the methane yield at high ammonia load (7 g NH4+-N L-1) was 41.0% and 22.3% lower than at low ammonia load (1 g NH4+-N L-1) in mesophilic...

  3. Diversity, Physiology, and Niche Differentiation of Ammonia-Oxidizing Archaea

    OpenAIRE

    Hatzenpichler, Roland

    2012-01-01

    Nitrification, the aerobic oxidation of ammonia to nitrate via nitrite, has been suggested to have been a central part of the global biogeochemical nitrogen cycle since the oxygenation of Earth. The cultivation of several ammonia-oxidizing archaea (AOA) as well as the discovery that archaeal ammonia monooxygenase (amo)-like gene sequences are nearly ubiquitously distributed in the environment and outnumber their bacterial counterparts in many habitats fundamentally revised our understanding o...

  4. The concentration of ammonia regulates nitrogen metabolism in Saccharomyces cerevisiae.

    OpenAIRE

    ter Schure, E G; Silljé, H H; Verkleij, A J; Boonstra, J; Verrips, C T

    1995-01-01

    Saccharomyces cerevisiae was grown in a continuous culture at a single dilution rate with input ammonia concentrations whose effects ranged from nitrogen limitation to nitrogen excess and glucose limitation. The rate of ammonia assimilation (in millimoles per gram of cells per hour) was approximately constant. Increased extracellular ammonia concentrations are correlated with increased intracellular glutamate and glutamine concentrations, increases in levels of NAD-dependent glutamate dehydro...

  5. 46 CFR 98.25-5 - How anhydrous ammonia may be carried.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false How anhydrous ammonia may be carried. 98.25-5 Section 98... Anhydrous Ammonia in Bulk § 98.25-5 How anhydrous ammonia may be carried. (a) Anhydrous ammonia shall be..., except as otherwise provided in paragraph (b) of this section. (b) When anhydrous ammonia is to...

  6. Process model for ammonia volatilization from anaerobic swine lagoons incorporating varying wind speeds and biogas bubbling

    Science.gov (United States)

    Ammonia volatilization from treatment lagoons varies widely with the total ammonia concentration, pH, temperature, suspended solids, atmospheric ammonia concentration above the water surface, and wind speed. Ammonia emissions were estimated with a process-based mechanistic model integrating ammonia ...

  7. Removal of ammonia solutions used in catalytic wet oxidation processes.

    Science.gov (United States)

    Hung, Chang Mao; Lou, Jie Chung; Lin, Chia Hua

    2003-08-01

    Ammonia (NH(3)) is an important product used in the chemical industry, and is common place in industrial wastewater. Industrial wastewater containing ammonia is generally either toxic or has concentrations or temperatures such that direct biological treatment is unfeasible. This investigation used aqueous solutions containing more of ammonia for catalytic liquid-phase oxidation in a trickle-bed reactor (TBR) based on Cu/La/Ce composite catalysts, prepared by co-precipitation of Cu(NO(3))(2), La(NO(3))(2), and Ce(NO(3))(3) at 7:2:1 molar concentrations. The experimental results indicated that the ammonia conversion of the wet oxidation in the presence of the Cu/La/Ce composite catalysts was determined by the Cu/La/Ce catalyst. Minimal ammonia was removed from the solution by the wet oxidation in the absence of any catalyst, while approximately 91% ammonia removal was achieved by wet oxidation over the Cu/La/Ce catalyst at 230 degrees C with oxygen partial pressure of 2.0 MPa. Furthermore, the effluent streams were conducted at a liquid hourly space velocity of under 9 h(-1) in the wet catalytic processes, and a reaction pathway was found linking the oxidizing ammonia to nitric oxide, nitrogen and water. The solution contained by-products, including nitrates and nitrites. Nitrite selectivity was minimized and ammonia removal maximized when the feed ammonia solution had a pH of around 12.0.

  8. Ammonia pollution characteristics of centralized drinking water sources in China.

    Science.gov (United States)

    Fu, Qing; Zheng, Binghui; Zhao, Xingru; Wang, Lijing; Liu, Changming

    2012-01-01

    The characteristics of ammonia in drinking water sources in China were evaluated during 2005-2009. The spatial distribution and seasonal changes of ammonia in different types of drinking water sources of 22 provinces, 5 autonomous regions and 4 municipalities were investigated. The levels of ammonia in drinking water sources follow the order of river > lake/reservoir > groundwater. The levels of ammonia concentration in river sources gradually decreased from 2005 to 2008, while no obvious change was observed in the lakes/reservoirs and groundwater drinking water sources. The proportion of the type of drinking water sources is different in different regions. In river drinking water sources, the ammonia level was varied in different regions and changed seasonally. The highest value and wide range of annual ammonia was found in South East region, while the lowest value was found in Southwest region. In lake/reservoir drinking water sources, the ammonia levels were not varied obviously in different regions. In underground drinking water sources, the ammonia levels were varied obviously in different regions due to the geological permeability and the natural features of regions. In the drinking water sources with higher ammonia levels, there are enterprises and wastewater drainages in the protected areas of the drinking water sources.

  9. Oxydesulfurization of a Turkish hard lignite with ammonia solutions

    Energy Technology Data Exchange (ETDEWEB)

    Yaman, S.; Kuecuekbayrak, S. [Istanbul Technical Univ. (Turkey). Chemical and Metallurgical Engineering Faculty

    1996-09-01

    In this study the desulfurization of a high pyritic and high organic sulfur lignite taken from the Gediz area (western Turkey) was investigated by the oxydesulfurization method using ammonia solutions. The influence of such parameters as the concentration of ammonia solution, partial pressure of oxygen, temperature, and reaction time were studied. The ranges of these parameters were selected as 0--10 M concentration of ammonia solution, 0--1.5 MPa partial pressure of oxygen, 403--473 K temperature, and 10--60 min reaction time. It was concluded that the use of ammonia solution as an extraction solution increased the efficiency of the oxydesulfurization process.

  10. Sugar-driven prebiotic synthesis of ammonia from nitrite.

    Science.gov (United States)

    Weber, Arthur L

    2010-06-01

    Reaction of 3-5 carbon sugars, glycolaldehyde, and alpha-ketoaldehydes with nitrite under mild anaerobic aqueous conditions yielded ammonia, an essential substrate for the synthesis of nitrogen-containing molecules during abiogenesis. Under the same conditions, ammonia synthesis was not driven by formaldehyde, glyoxylate, 2-deoxyribose, and glucose, a result indicating that the reduction process requires an organic reductant containing either an accessible alpha-hydroxycarbonyl group or an alpha-dicarbonyl group. Small amounts of aqueous Fe(+3) catalyzed the sugar-driven synthesis of ammonia. The glyceraldehyde concentration dependence of ammonia synthesis, and control studies of ammonia's reaction with glyceraldehyde, indicated that ammonia formation is accompanied by incorporation of part of the synthesized ammonia into sugar-derived organic products. The ability of sugars to drive the synthesis of ammonia is considered important to abiogenesis because it provides a way to generate photochemically unstable ammonia at sites of sugar-based origin-of-life processes from nitrite, a plausible prebiotic nitrogen species.

  11. Ammonia pollution characteristics of centralized drinking water sources in China

    Institute of Scientific and Technical Information of China (English)

    Qing Fu; Binghui Zheng; Xingru Zhao; Lijing Wang; Changming Liu

    2012-01-01

    The characteristics of ammonia in drinking water sources in China were evaluated during 2005-2009.The spatial distribution and seasonal changes of ammonia in different types of drinking water sources of 22 provinces,5 autonomous regions and 4 municipalities were investigated.The levels of ammonia in drinking water sources follow the order of river > lake/reservoir > groundwater.The levels of ammonia concentration in river sources gradually decreased from 2005 t0 2008,while no obvious change was observed in the lakes/reservoirs and groundwater drinking water sources.The proportion of the type of drinking water sources is different in different regions.In river drinking water sources,the ammonia level was varied in different regions and changed seasonally.The highest value and wide range of annual ammonia was found in South East region,while the lowest value was found in Southwest region.In lake/reservoir drinking water sources,the ammonia levels were not varied obviously in different regions.In underground drinking water sources,the ammonia levels were varied obviously in different regions due to the geological permeability and the natural features of regions.In the drinking water sources with higher ammonia levels,there are enterprises and wastewater drainages in the protected areas of the drinking water sources.

  12. [Toxic effects of high concentrations of ammonia on Euglena gracilis].

    Science.gov (United States)

    Liu, Yan; Shi, Xiao-Rong; Cui, Yi-Bin; Li, Mei

    2013-11-01

    Ammonia is among the common contaminants in aquatic environments. The present study aimed at evaluation of the toxicity of ammonia at high concentration by detecting its effects on the growth, pigment contents, antioxidant enzyme activities, and DNA damage (comet assay) of a unicellular microalga, Euglena gracilis. Ammonia restrained the growth of E. gracilis, while at higher concentrations, ammonia showed notable inhibition effect, the growth at 2 000 mg x L(-1) was restrained to 55.7% compared with that of the control; The contents of photosynthetic pigments and protein went up with increasing ammonia dosage and decreased when the ammonia concentration was above 1000 mg x L(-1); In addition, there was an obvious increase in SOD and POD activities, at higher concentration (2 000 mg x L(-1)), activities of SOD and POD increased by 30.7% and 49.4% compared with those of the control, indicating that ammonia could promote activities of antioxidant enzymes in E. gracilis; The degree of DNA damage observed in the comet assay increased with increasing ammonia concentration, which suggested that high dose of ammonia may have potential mutagenicity on E. gracilis.

  13. Exposure of lambs to atmospheric ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Drummond, J.G.; Curtis, S.E.; Lewis, J.M.; Hinds, F.C.; Simon, J.

    1976-01-01

    Two trials were conducted to determine the effects of chronic exposure to atmospheric ammonia at a concentration of 75 ppm on weight gain and efficiency of feed conversion by lambs. Lambs were weighed and then randomly allotted to four dynamic air-pollutant exposure chambers. Initial weights (mean +/- SE) of lambs were 22.1 +/- .46 kg and 27.5 +/- 1.54 kg for trials 1 and 2, respectively (n=12 in both trials). Lambs in two chambers (controls) were maintained in an atmosphere of filtered room air. Lambs in the other two chambers (NH/sub 3/ -exposed) were exposed to an atmosphere of filtered air plus atmospheric ammonia at a concentration of 75 ppm. Exposure period was 28 days in both trials. Feed and water were available at all times. Lamb weight gain and feed disappearance were determined weekly. Upon termination of each trial, one lamb was randomly selected from each chamber, sacrificed, and gross and histopathologic structural changes noted. Weight gain and efficiency of feed conversion data for the two trials were combined for statistical analysis. Control lambs gained on the average .09 kg/day (.28 vs .19) more (P<.01) and consumed on the average .68 kg of feed (4.53 vs 5.21) less per kilogram of weight gain (P<.10) than did NH/sub 3/-exposed lambs. Ammonia-exposed lambs in both trials showed profuse lacrimation, severe coughing and sneezing, and profuse nasal discharge, which was bloody in some instances. Gross and histopathologic findings appeared to be qualitatively similar between treatments, but more pronounced in NH/sub 3/-exposed lambs.

  14. AMMONIA-FREE NOx CONTROL SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Song Wu; Zhen Fan; Andrew H. Seltzer; Richard G. Herman

    2006-06-01

    This report describes a novel NOx control system that has the potential to drastically reduce cost, and enhance performance, operation and safety of power plant NOx control. The new system optimizes the burner and the furnace to achieve very low NOx levels and to provide an adequate amount of CO, and uses the CO for reducing NO both in-furnace and over a downstream AFSCR (ammonia-free selective catalytic reduction) reactor. The AF-SCR combines the advantages of the highly successful SCR technology for power plants and the TWC (three-way catalytic converter) widely used on automobiles. Like the SCR, it works in oxidizing environment of combustion flue gas and uses only base metal catalysts. Like the TWC, the AF-SCR removes NO and excess CO simultaneously without using any external reagent, such as ammonia. This new process has been studied in a development program jointed funded by the US Department of Energy and Foster Wheeler. The report outlines the experimental catalyst work performed on a bench-scale reactor, including test procedure, operating conditions, and results of various catalyst formulations. Several candidate catalysts, prepared with readily available transition metal oxides and common substrate materials, have shown over 80-90% removal for both NO and CO in oxidizing gas mixtures and at elevated temperatures. A detailed combustion study of a 400 MWe coal-fired boiler, applying computational fluid dynamics techniques to model boiler and burner design, has been carried out to investigate ways to optimize the combustion process for the lowest NOx formation and optimum CO/NO ratios. Results of this boiler and burner optimization work are reported. The paper further discusses catalyst scale-up considerations and the conceptual design of a 400 MWe size AF-SCR reactor, as well as economics analysis indicating large cost savings of the ammonia-free NOx control process over the current SCR technology.

  15. Ammonia and urea excretion in the swimming crab Portunus trituberculatus exposed to elevated ambient ammonia-N.

    Science.gov (United States)

    Ren, Qin; Pan, Luqing; Zhao, Qun; Si, Lingjun

    2015-09-01

    In the present study of the swimming crab Portunus trituberculatus exposed to 0, 1, and 5 mg L(-1) NH4Cl, the effects of ammonia exposure on ammonia and urea content in hemolymph; activity of H(+)-ATPase (subunit A) and Na(+)/K(+)-ATPase (α-subunit) (NKA) in gills; mRNA expression levels of the crustacean Rh-like ammonia transporter (Rh), K(+) Channel, Na(+)/K(+)/2Cl(-) co-transporter (NKCC), Na(+)/H(+)-exchanger (NHE), urea transporter (UT) and vesicle associated membrane protein (VAMP) in gills were investigated. The ultrastructure of gills was also evaluated. All these results in this study showed a dose-dependent effect with ammonia exposure concentration. The data displayed a significant increase in hemolymph ammonia and urea concentrations under ammonia exposure. The up-regulation of Rh mRNA together with up-regulation of K(+)-channel mRNA, NKA activity, down-regulation of NKCC and NHE mRNA suggested a coordinated protective response to maintain a relatively low ammonia concentration in the body fluids during ambient ammonia exposure. The up-regulation of VAMP, H(+)-ATPase activity along with the ultrastructure of gills suggested a mechanism of exocytotic ammonia excretion that may exit in the gill of P. trituberculatus. An increased production of urea and the up-regulated expression of UT suggested that the crab can detoxify elevated ammonia levels in the body fluids into urea when pathways of ammonia excretion are decreased after long term ammonia exposure.

  16. Innovative bioelectrochemical-anaerobic-digestion integrated system for ammonia recovery and bioenergy production from ammonia-rich residues

    OpenAIRE

    Zhang, Yifeng; Angelidaki, Irini

    2015-01-01

    Ammonia (NH4+/NH3) inhibition during anaerobic digestion process is one of the most frequent problems existing in biogas plants, resulting in unstable process and reduced biogas production. In this study, we developed a novel hybrid system, consisted of a submersed microbial resource recovery cell (SMRC) and a continuous stirred tank reactor (CSTR), to prevent ammonia toxicity during anaerobic digestion by in-situ ammonia recovery and electricity production (Figure 1). In batch experiment, th...

  17. TES ammonia retrieval strategy and global observations of the spatial and seasonal variability of ammonia (journal)

    Science.gov (United States)

    Presently only limited sets of tropospheric ammonia (NH3) measurements in the Earth's atmosphere have been reported from satellite and surface station measurements, despite the well-documented negative impact of NH3 on the environment and human health. Presented here is a detaile...

  18. The importance of the ammonia purification process in ammonia-water absorption systems

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Seara, Jose [Area de Maquinas y Motores Termicos, Escuela Tecnica Superior de Ingenieros Industriales, Universidad de Vigo, Campus Lagoas-Marcosende No. 9, 36200 Vigo (Spain)]. E-mail: jseara@uvigo.es; Sieres, Jaime [Area de Maquinas y Motores Termicos, Escuela Tecnica Superior de Ingenieros Industriales, Universidad de Vigo, Campus Lagoas-Marcosende No. 9, 36200 Vigo (Spain)

    2006-08-15

    Practical experience in working with ammonia-water absorption systems shows that the ammonia purification process is a crucial issue in order to obtain an efficient and reliable system. In this paper, the detrimental effects of the residual water content in the vapour refrigerant are described and quantified based on the system design variables that determine the effectiveness of the purification process. The study has been performed considering a single stage system with a distillation column with complete condensation. The ammonia purification effectiveness of the column is analysed in terms of the efficiencies in the stripping and rectifying sections and the reflux ratio. By varying the efficiencies from 0 to 1, systems with neither the rectifying nor stripping section, with either the rectifying or stripping section, or with both sections can be considered. The impact of the ammonia purification process on the absorption system performance is studied based on the column efficiencies and reflux ratio; and its effects on refrigerant concentration, system COP, system pressures and main system mass flow rates and concentrations are analysed. When the highest efficiency rectifying sections are used a combination of generation temperature and reflux ratio which leads to optimum COP values is found. The analysis covers different operating conditions with air and water cooled systems from refrigeration to air conditioning applications by changing the evaporation temperature. The importance of rectification in each kind of application is evaluated.

  19. DIRECT AMMONIA-AIR FUEL CELL.

    Science.gov (United States)

    fuel cell was investigated. This cell is based on the use of a non-aqueous fused hydroxide electrolyte matrix, and operates in the intermediate temperature range of 180-300 C. Studies have been carried out to determine the nature of the ratecontrolling step in the kinetics of the anodic oxidation of ammonia. A new type of Ni/NiOOH reference electrode was developed for the measurement of single electrode potentials in experimental galvanic fuel cells employing this type of matrix electrolyte. In addition to various exploratory studies, two statistical analysis

  20. Ammonia-Free NOx Control System

    Energy Technology Data Exchange (ETDEWEB)

    Song Wu; Zhen Fan; Andrew H. Seltzer; Richard G. Herman

    2005-03-31

    Research is being conducted under United States Department of Energy (DOE) Contract DE-FC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia.

  1. 吡啶硼烷改性对沥青性能及组成的影响%INFLUENCE OF PYRIDINE-BORANE MODIFICATION ON THE PROPERTIES AND COMPONENT OF PITCHES

    Institute of Scientific and Technical Information of China (English)

    张丽芳; 宋进仁; 要立中; 刘朗

    2001-01-01

    以吡啶硼烷为添加剂对煤焦油沥青进行改性,考察了工艺条件(硼添加量,反应温度,反应时间)对改性沥青软化点、残炭值及其族组成的影响。发现吡啶硼烷参与并促进了沥青分子的反应,其结果是随着硼添加量的增加,改性沥青的软化点、残炭值提高,TS组份的含量降低,而PI组份的含量增加。在同一反应条件下,体系有无吡啶硼烷,所得结果有显著差别。吡啶硼烷改性系列的软化点、残炭值及PI组份的含量均明显高于纯沥青系列。%Coal tar pitch was modified by adding pyridine-borane. The effectof reaction conditions on the properties and components of modified pitches was investigated. It was found that pyridine-borane participate in and accelerated the reaction among molecules, but changed the component and structure of pitches. The softening points, carbon yields and PI fraction content increased with the increasing of boron addition and reaction temperature, while TS fraction content of pitches decreased. Compared with the pure pitches, pyridine-borane modified pitches had higher softening points, carbon yields and PI fraction content at the same reaction conditions.

  2. Development of compound layer during nitriding and nitrocarburising

    DEFF Research Database (Denmark)

    Somers, Marcel A. J.

    2010-01-01

    The development of the compound layer during gaseous nitriding and nitrocarburising of Fe-based material is described. The first nucleation of the compound layer at the surface depends on the competition between dissociation of ammonia and the removal nitrogen from the surface by solid state...... diffusion and desorption or the competition with a carburising reaction. During layer growth surface reactions as well as solid state diffusion and phase transformations determine the layer growth kinetics....

  3. Modeling and simulation of ammonia removal from purge gases of ammonia plants using a catalytic Pd-Ag membrane reactor.

    Science.gov (United States)

    Rahimpour, M R; Asgari, A

    2008-05-01

    In this work, the removal of ammonia from synthesis purge gas of an ammonia plant has been investigated. Since the ammonia decomposition is thermodynamically limited, a membrane reactor is used for complete decomposition. A double pipe catalytic membrane reactor is used to remove ammonia from purge gas. The purge gas is flowing in the reaction side and is converted to hydrogen and nitrogen over nickel-alumina catalyst. The hydrogen is transferred through the Pd-Ag membrane of tube side to the shell side. A mathematical model including conservation of mass in the tube and shell side of reactor is proposed. The proposed model was solved numerically and the effects of different parameters on the rector performance were investigated. The effects of pressure, temperature, flow rate (sweep ratio), membrane thickness and reactor diameter have been investigated in the present study. Increasing ammonia conversion was observed by raising the temperature, sweep ratio and reducing membrane thickness. When the pressure increases, the decomposition is gone toward completion but, at low pressure the ammonia conversion in the outset of reactor is higher than other pressures, but complete destruction of the ammonia cannot be achieved. The proposed model can be used for design of an industrial catalytic membrane reactor for removal of ammonia from ammonia plant and reducing NO(x) emissions.

  4. Improving The Efficiency Of Ammonia Electrolysis For Hydrogen Production

    Science.gov (United States)

    Palaniappan, Ramasamy

    Given the abundance of ammonia in domestic and industrial wastes, ammonia electrolysis is a promising technology for remediation and distributed power generation in a clean and safe manner. Efficiency has been identified as one of the key issues that require improvement in order for the technology to enter the market phase. Therefore, this research was performed with the aim of improving the efficiency of hydrogen production by finding alternative materials for the cathode and electrolyte. 1. In the presence of ammonia the activity for hydrogen evolution reaction (HER) followed the trend Rh>Pt>Ru>Ni. The addition of ammonia resulted in lower rates for HER for Pt, Ru, and Ni, which have been attributed to competition from the ammonia adsorption reaction. 2. The addition of ammonia offers insight into the role of metal-hydrogen underpotential deposition (M-Hupd) on HER kinetics. In addition to offering competition via ammonia adsorption it resulted in fewer and weaker M-Hupd bonds for all metals. This finding substantiates the theory that M-Hupd bonds favor HER on Pt electrocatalyst. However, for Rh results suggest that M-Hupd bond may hinder the HER. In addition, the presence of unpaired valence shell electrons is suggested to provide higher activity for HER in the presence of ammonia. 3. Bimetals PtxM1-x (M = Ir, Ru, Rh, and Ni) offered lower overpotentials for HER compared to the unalloyed metals in the presence of ammonia. The activity of HER in the presence of ammonia follows the trend Pt-Ir>Pt-Rh>Pt-Ru>Pt-Ni. The higher activity of HER is attributed to the synergistic effect of the alloy, where ammonia adsorbs onto the more electropositive alloying metal leaving Pt available for Hupd formation and HER to take place. Additionally, this supports the theory that the presence of a higher number of unpaired electrons favors the HER in the presence of ammonia. 4. Potassium polyacrylate (PAA-K) was successfully used as a substitute for aqueous KOH for ammonia

  5. Emergency planning and the acute toxic potency of inhaled ammonia.

    Science.gov (United States)

    Michaels, R A

    1999-08-01

    Ammonia is present in agriculture and commerce in many if not most communities. This report evaluates the toxic potency of ammonia, based on three types of data: anecdotal data, in some cases predating World War 1, reconstructions of contemporary industrial accidents, and animal bioassays. Standards and guidelines for human exposure have been driven largely by the anecdotal data, suggesting that ammonia at 5,000-10,000 parts per million, volume/volume (ppm-v), might be lethal within 5-10 min. However, contemporary accident reconstructions suggest that ammonia lethality requires higher concentrations. For example, 33,737 ppm-v was a 5-min zero-mortality value in a major ammonia release in 1973 in South Africa. Comparisons of secondary reports of ammonia lethality with original sources revealed discrepancies in contemporary sources, apparently resulting from failure to examine old documents or accurately translate foreign documents. The present investigation revealed that contemporary accident reconstructions yield ammonia lethality levels comparable to those in dozens of reports of animal bioassays, after adjustment of concentrations to human equivalent concentrations via U.S. Environmental Protection Agency (EPA) procedures. Ammonia levels potentially causing irreversible injury or impairing the ability of exposed people to escape from further exposure or from coincident perils similarly have been biased downwardly in contemporary sources. The EPA has identified ammonia as one of 366 extremely hazardous substances subject to community right-to-know provisions of the Superfund Act and emergency planning provisions of the Clean Air Act. The Clean Air Act defines emergency planning zones (EPZs) around industrial facilities exceeding a threshold quantity of ammonia on-site. This study suggests that EPZ areas around ammonia facilities can be reduced, thereby also reducing emergency planning costs, which will vary roughly with the EPZ radius squared.

  6. Biofilter Treating Ammonia Gas Using Agricultural Residues Media

    Directory of Open Access Journals (Sweden)

    Thaniya Kaosol

    2012-01-01

    Full Text Available Problem statement: Agricultural residues such as manure and sugarcane bagasse are wastes from agro-industry which has low value and requires some sustainable waste management method. In this research, a mixture of manure fertilizer and sugarcane bagasse is used as a biofilter media for an ammonia gas removal application. The aim of this research is to study the ammonia gas removal efficiency of such media. Approach: The experiments were conducted in laboratory-scale biofilters. Two inlet ammonia gas concentrations were used which are 500 and 1,000 ppm. Three ratios of manure fertilizer and sugarcane bagasse were studied including 1:3, 1:5 and 1:7 by volume. All experiments were conducted for a period of 40 days. Two Empty Bed Retention Time (EBRT of these experiments were used which is 39s and 78s. The moisture content of the biofilter media was maintained at 45-60% by adding water. Results: The maximum ammonia gas removal efficiency at 89.93% is observed from the following conditions: 500 ppm of the inlet ammonia gas concentration, the manure fertilizer and sugarcane bagasse mixture ratio of 1:5 and the EBRT of 78s. The important factors of the ammonia gas removal in biofiltration process are the inlet ammonia gas concentration and the EBRT. Conclusion: The experimental results showed that the mixture of manure fertilizer and sugarcane bagasse is an effective biofilter media for ammonia gas removal applications. However, the biofilter is more effective at low inlet ammonia gas concentration, while the ratio of manure fertilizer and sugarcane bagasse has no significant effect on the ammonia gas removal efficiency. Therefore, using both residues as biofilter media for ammonia gas removal application is an alternative sustainable way to such manage argo-industry waste.

  7. Enantiomeric excesses of chiral amines in ammonia-rich carbonaceous meteorites

    Science.gov (United States)

    Pizzarello, Sandra; Yarnes, Christopher T.

    2016-06-01

    Chiral homogeneity is essential to the structure and function of terrestrial biopolymers but the origin of this "homochirality" is poorly understood and remains one of the many unknowns surrounding the origins of life. Several amino acids extracted from Carbonaceous Chondrite meteorites display L-enantiomeric excesses (ee) and their findings have encouraged suggestions that an input of non-racemic meteoritic compounds to early Earth might have led to terrestrial homochirality. Motivated by occasional indications of possible ee in other classes of soluble meteoritic compounds, we have undertaken a systematic study of the chiral distribution of amines in Renazzo-type (CR) meteorites, where they are the second most abundant organic molecular species and ammonia is by far the most abundant single molecule. We report here the first time finding of L-ee for two chiral amines in several pristine CR meteorites from Antarctica and outline a proposal by which the compounds possibly formed from the same ketone precursors as some of the chiral amino acids. This would occur during a warm hydrous stage of the asteroidal parent body, via a reductive amination process in the presence of a large abundance of ammonia, where the precursors' adsorption upon mineral phases possessing asymmetry offered the opportunity for chiral induction. Because the precursor ketones are achiral, the proposal underscores the likelihood of diverse asymmetric influences and processes in cosmochemistry.

  8. Semi-batch absorption and regeneration studies for CO{sub 2} capture by aqueous ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, James T.; Resnik, Kevin P.; Rygle, Kathy; Pennline, Henry W. [U.S. Department of Energy, National Energy Technology Laboratory, P.O.Box 10940, Pittsburgh, PA 15236 (United States)

    2005-10-15

    Carbon dioxide transfer capacities of aqueous ammonia solution and monoethanolamine (MEA) solution were compared. The ammonia process for CO{sub 2} capture was simulated using a semibatch reactor, where the flow of gas is continuous. The CO{sub 2} carrying capacity in g CO{sub 2} per g of NH{sub 3} solution (8 wt.%) circulated is 0.07 as compared with 0.036 g CO{sub 2} per g MEA solution (20 wt.%). The energy requirement for liquid mass circulation of ammonia solution is approximately 50% of MEA solution for equal weight of CO{sub 2} carried. In another comparison, the thermal energy required to regenerate CO{sub 2} from the rich solution is substantially less as compared to the MEA process. A 3-cycle absorption-regeneration test was conducted in the semibatch reactor to simulate an approach-to-steady state in a flow system. pH values of the absorbent solution was found to oscillate between 9.6 (CO{sub 2}-lean) and 8.8 (CO{sub 2}-rich) under the test conditions. Thermodynamics study shows that ammonium bicarbonate required the least thermal energy among the ammonium compounds for CO{sub 2} regeneration. (author)

  9. Biomass production from electricity using ammonia as an electron carrier in a reverse microbial fuel cell.

    Directory of Open Access Journals (Sweden)

    Wendell O Khunjar

    Full Text Available The storage of renewable electrical energy within chemical bonds of biofuels and other chemicals is a route to decreasing petroleum usage. A critical challenge is the efficient transfer of electrons into a biological host that can covert this energy into high energy organic compounds. In this paper, we describe an approach whereby biomass is grown using energy obtained from a soluble mediator that is regenerated electrochemically. The net result is a separate-stage reverse microbial fuel cell (rMFC that fixes CO₂ into biomass using electrical energy. We selected ammonia as a low cost, abundant, safe, and soluble redox mediator that facilitated energy transfer to biomass. Nitrosomonas europaea, a chemolithoautotroph, was used as the biocatalyst due to its inherent capability to utilize ammonia as its sole energy source for growth. An electrochemical reactor was designed for the regeneration of ammonia from nitrite, and current efficiencies of 100% were achieved. Calculations indicated that overall bioproduction efficiency could approach 2.7±0.2% under optimal electrolysis conditions. The application of chemolithoautotrophy for industrial bioproduction has been largely unexplored, and results suggest that this and related rMFC platforms may enable biofuel and related biochemical production.

  10. A case of indoor air pollution of ammonia emitted from concrete in a newly built office in Beijing

    Energy Technology Data Exchange (ETDEWEB)

    Lindgren, Torsten [Department of Medical Sciences/Occupational and Environmental Medicine, Uppsala University, University Hospital, SE-751 85 Uppsala (Sweden)

    2010-03-15

    A case of suspected indoor ammonia contamination from concrete was investigated in an airline company office in Beijing. A standardized questionnaire on indoor environment perceptions, medical symptoms and psychosocial work environment was distributed to all staff, and compared with a reference group of office workers from the same company in Stockholm. Temperature, relative humidity, formaldehyde, volatile organic compounds (VOC), ammonia, and carbon dioxide were measured both in Beijing and Stockholm. In Beijing mould and bacteria were also measured. Totally 95% (N = 14) participated. The Beijing staff reported a higher rate of complaints regarding poor work satisfaction, and work stress as compared to the Stockholm reference group. In the total material (N = 203) the psychosocial environment was related to general symptoms (headache and tiredness) but not odour perception or mucous membrane symptoms. Controlling for age, smoking habits, and psychosocial work environment the Beijing staff had more complaints on unpleasant odour and mucous membrane symptoms. An increased indoor concentration of ammonia (3-6 ppm) and benzene (26.8 {mu}g/m{sup 3}) was measured in the indoor air in the Beijing office, as compared to the office in Stockholm (<0.1 ppm ammonia and 0.4 {mu}g/m{sup 3} benzene). The ammonia contamination in the Beijing office was confirmed, the probable source being additives in the concrete. The ammonia level was well below the Swedish threshold limit values (TLV) (25 ppm). In addition the exposure to benzene, an indicator of traffic exhaust pollution was high both indoors and outdoors in Beijing, possible related to increased levels of odour complaints and mucous membrane irritation. (author)

  11. PRETREATMENT AND FRACTIONATION OF CORN STOVER BY AMMONIA RECYCLE PERCOLATION PROCESS. (R831645)

    Science.gov (United States)

    Corn stover was pretreated with aqueous ammonia in a flow-through column reactor,a process termed as Ammonia Recycle Percolation (ARP). The aqueous ammonia causesswelling and efficient delignification of biomass at high temperatures. The ARPprocess solubilizes abou...

  12. Nitrogen Compounds in Radiation Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Sims, H.E. [NNL Sellafield (United Kingdom); Dey, G.R. [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Vaudey, C.E.; Peaucelle, C. [Institut de Physique Nucleaire de Lyon - IPNL, 69 - Lyon (France); Boucher, J.L. [Lab. de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601 CNRS 45 rue des Saints Peres, 75270 Paris cedex 06, Univ Paris 5, 75 (France); Toulhoat, N. [Institut de Physique Nucleaire de Lyon (France); Commissariat a l' Energie Atomique CEA/DEN, Centre de Saclay (France); Bererd, N. [Institut de Physique Nucleaire de Lyon (France); IUT Departement Chimie, Universite Claude Bernard Lyon 1 (France); Koppenol, W.H. [Department of Chemistry and Applied Biosciences, ETH Zurich (Switzerland); Janata, E. [Helmholtz-Zentrum fuer Materialien und Energie, Solar Energy Research, Berlin (Germany); Dauvois, V.; Durand, D.; Legand, S.; Roujou, J.L.; Doizi, D.; Dannoux, A.; Lamouroux, C. [Laboratoire de Speciation des Radionucleides et des Molecules, DEN/DPC/Service d' Etude du Comportement des Radionucleides, CEA Saclay, 91 - Gif sur yvette (France)

    2009-07-01

    Water radiolysis in presence of N{sub 2} is probably the topic the most controversy in the field of water radiolysis. It still exists a strong discrepancy between the different reports of ammonia formation by water radiolysis in presence of N{sub 2} and moreover in absence of oxygen there is no agreement on the formation or not of nitrogen oxide like NO{sub 2}- and NO{sub 3}-. These discrepancies come from multiple sources: - the complexity of the reaction mechanisms where nitrogen is involved - the experimental difficulties - and, the irradiation conditions. The aim of the workshop is to capitalize the knowledge needed to go further in simulations and understanding the problems caused (or not) by the presence of nitrogen / water in the environment of radioactive materials. Implications are evident in terms of corrosion, understanding of biological systems and atmospheric chemistry under radiation. Topics covered include experimental and theoretical approaches, application and fundamental researches: - Nitrate and Ammonia in radiation chemistry in nuclear cycle; - NOx in biological systems and atmospheric chemistry; - Formation of Nitrogen compounds in Nuclear installations; - Nitrogen in future power plant projects (Gen4, ITER...) and large particle accelerators. This document gathers the transparencies available for 7 of the presentations given at this workshop. These are: - H.E SIMS: 'Radiation Chemistry of Nitrogen Compounds in Nuclear Power Plant'; - G.R. DEY: 'Nitrogen Compounds Formation in the Radiolysis of Aqueous Solutions'; - C.E. VAUDEY et al.: 'Radiolytic corrosion of nuclear graphite studied with the dedicated gas irradiation cell of IPNL'; - J.L. BOUCHER: 'Roles and biosynthesis of NO in eukaryotes and prokaryotes'; - W.H. KOPPENOL: 'Chemistry of NOx'; - E. JANATA: 'Yield of OH in N{sub 2}O saturated aqueous solution'; - V. DAUVOIS: 'Analytical strategy for the study of radiolysis gases'

  13. Energy retrofit study of an ammonia plant

    Energy Technology Data Exchange (ETDEWEB)

    Lababidi, H.M.S.; Alatiqi, I.M.; Nayfeh, L.J. [Kuwait University Safat (Kuwait). Dept. of Chemical Engineering

    2000-11-01

    Detailed energy integration study of the front-end of an existing ammonia plant has been performed, using recent advances in Pinch technology. Utility loads demanded by the existing process were found to be very close to the calculated minimum targets. This indicated that the selected ammonia plant is well integrated, and not much saving is expected through process-to-process energy integration. Alternatively, the retrofit study concentrated on better placement of available utilities. Two promising options have been investigated. The first one studied the flue gas temperature in the convection section of the primary reformer, and proposed new arrangements of the heating coils. Boiler feed water heating for high-pressure steam generation has been also considered as a possible source for reduction in energy consumption. Total benefit claimed amounted to 17.6% reduction in combustion fuel consumption. The overall results of this case study are promising. However, economical evaluation of the proposed modifications is essential. Additional possible reduction in energy consumption is also possible in energy and power integration of the back-end section. (author)

  14. Energy efficient ammonia heat pump. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Madsen, Claus; Pijnenburg, B.; Schumann Grindorf, H. [Danish Technological Institute, Aarhus (Denmark); Christensen, Rolf [Alfa Laval, Lund (Sweden); Rasmussen, Bjarne D. [Grundfos, Bjerringbro (Denmark); Gram, S.; Fredborg Jakobsen, D. [Svedan Industri Koeleanlaeg, Greve (Denmark)

    2013-09-15

    The report describes the development of a highly effective ammonia heat pump. Heat pumps play an increasingly important role in the search for more effective use of energy in our society. Highly efficient heat pumps can contribute to reduced energy consumption and improved economy of the systems which they are a part of. An ammonia heat pump with high pressure reciprocating compressor and a novel split condenser was developed to prove potential for efficiency optimization. The split of the condenser in two parts can be utilized to obtain smaller temperature approaches and, thereby, improved heat pump efficiency at an equal heat exchanger area, when compared to the traditional solution with separate condenser and de-superheater. The split condenser design can also be exploited for heating a significant share of the total heating capacity to a temperature far above the condensing temperature. Furthermore, the prototype heat pump was equipped with a plate type evaporator combined with a U-turn separator with a minimum liquid height and a liquid pump with the purpose of creating optimum liquid circulation ratio for the highest possible heat transfer coefficients at the lowest possible pressure drop. The test results successfully confirmed the highest possible efficiency; a COP of 4.3 was obtained when heating water from 40 deg. C to 80 deg. C while operating with evaporating/condensing temperatures of +20 deg C/+73 deg C. (Author)

  15. Polybenzimidazole compounds

    Science.gov (United States)

    Klaehn, John R.; Peterson, Eric S.; Wertsching, Alan K.; Orme, Christopher J.; Luther, Thomas A.; Jones, Michael G.

    2010-08-10

    A PBI compound that includes imidazole nitrogens, at least a portion of which are substituted with an organic-inorganic hybrid moiety. At least 85% of the imidazole nitrogens may be substituted. The organic-inorganic hybrid moiety may be an organosilane moiety, for example, (R)Me.sub.2SiCH.sub.2--, where R is selected from among methyl, phenyl, vinyl, and allyl. The PBI compound may exhibit similar thermal properties in comparison to the unsubstituted PBI. The PBI compound may exhibit a solubility in an organic solvent greater than the solubility of the unsubstituted PBI. The PBI compound may be included in separatory media. A substituted PBI synthesis method may include providing a parent PBI in a less than 5 wt % solvent solution. Substituting may occur at about room temperature and/or at about atmospheric pressure. Substituting may use at least five equivalents in relation to the imidazole nitrogens to be substituted or, preferably, about fifteen equivalents.

  16. Effects of phenylalanine ammonia lyase (PAL) knockdown on cell wall composition, biomass digestibility, and biotic and abiotic stress responses in Brachypodium

    Science.gov (United States)

    Phenylalanine Ammonia Lyase (PAL) catalyzes the first step in the phenylpropanoid pathway in plants, controlling biosynthesis of a variety of structural and defense compounds including monolignols that polymerize into lignin. Gaps remain in our understanding of how genetic alterations to this pathwa...

  17. Determination of the In Vitro and In Vivo Activity of Compounds Tested against Punta Toro Virus

    Science.gov (United States)

    2016-02-09

    by Biological Research Faculty and Facility, Inc. (Rockville, MD). Compounds synthesized by Pharmatek, Inc. were especially prepared using...without stopping the deaminase reaction and dried at room temperature for 15 minutes. Plates were developed with 2- propanoi-aqueous ammonia (fresh...dry overnight to eliminate any traces of free ammonia . Plates were placed in a 2000 ml beaker layered with a 0.5 cm layer of CaHCI03, covered, and

  18. Lithium insertion into boron containing carbons prepared by co-pyrolysis of coal-tar pitch and borane-pyridine complex

    Energy Technology Data Exchange (ETDEWEB)

    Machnikowski, J.; Frackowiak, E.; Kierzek, K.; Waszak, D.; Benoit, R.; Beguin, F. [Wroclaw University of Technology, Wroclaw (Poland)

    2004-03-01

    Carbon materials of boron content ranging from 0.6 to 4 wt.% were synthesized by co-pyrolysis of QI-free coal-tar pitch with the borane-pyridine complex. The growing amount of boron introduced into the carbonaceous material is associated with an increase in nitrogen content and a progressive degradation of structural and textural ordering. The structural variations of the boron-doped materials on heat treatment up to 2500{sup o}C were monitored using X-ray diffraction and X-ray photoelectron spectroscopy. The intrinsic boron acts effectively as a catalyst of graphitization above 2100{sup o}C. The carbonaceous material with boron content of about 1.5 wt% shows the highest degree of structural ordering after thermal treatment. A high amount of oxygen was found in the graphitized boronated carbons, proving that the incorporated boron induces a strong chemisorption activity of the material when exposed to air. For a series of cokes calcined at 1000 {sup o}C, the most striking effect of increasing the boron content is an increase of irreversible capacity X-irr from 0.2 to 0.7. The reversible capacity (X-rev) amounts to about 1, with a slight tendency to decrease with the boron content. Upon increasing the temperature up to 2500{sup o}C, X-irr decreases to about 0.1 in the graphitic carbons, while X-rev reaches a minimum of 0.4-0.5 at 1700{sup o}C and next increases to a value close to 1 at 2500{sup o}C. In the boron doped graphite, X-irr has a slight tendency to increase with the boron content, due to the simultaneous presence of nitrogen in these materials and their strong affinity for oxygen from the atmosphere.

  19. Managing Ammonia Emissions From Screwworm Larval Rearing Media.

    Science.gov (United States)

    Sagel, Agustin; Phillips, Pamela; Chaudhury, Muhammad; Skoda, Steven

    2016-02-01

    Mass production, sterilization, and release of screwworms (Cochliomyia hominivorax (Coquerel)) that were competitive in the field significantly contributed to the successful application of the sterile insect technique for eradication of screwworms from continental North America. Metabolic byproducts resulting from protein-rich diets required for larval screwworms lead to ammonia liberation, sometimes at high levels, within the mass rearing facility. Until recently a sodium polyacrylate gel bulking agent was used for the larval media and adsorbed much of the ammonia. A need to replace the gel with an environmentally "friendly" bulking agent, while not increasing ammonia levels in the rearing facility, led to a series of experiments with the objective of developing procedures to reduce ammonia emissions from the larval media bulked with cellulose fiber. Additives of ammonia-converting bacteria, potassium permanganate, and Yucca schidigera Roezl ex Otrgies powder extract, previously reported to reduce ammonia levels in organic environments, were evaluated. Ammonia-converting bacteria did not have a positive effect. Addition of Y. schidigera powder extract (∼1% of total volume), potassium permanganate (∼250 ppm), and a combination of these two additives (at these same concentrations) kept ammonia at equivalent levels as when larval media was bulked with gel. Potassium permanganate also had sufficient antimicrobial properties that the use of formaldehyde in the diet was not necessary. Further testing is needed, at a mass rearing level, before full implementation into the screwworm eradication program.

  20. Ammonia Induces Autophagy through Dopamine Receptor D3 and MTOR.

    Science.gov (United States)

    Li, Zhiyuan; Ji, Xinmiao; Wang, Wenchao; Liu, Juanjuan; Liang, Xiaofei; Wu, Hong; Liu, Jing; Eggert, Ulrike S; Liu, Qingsong; Zhang, Xin

    2016-01-01

    Hyperammonemia is frequently seen in tumor microenvironments as well as in liver diseases where it can lead to severe brain damage or death. Ammonia induces autophagy, a mechanism that tumor cells may use to protect themselves from external stresses. However, how cells sense ammonia has been unclear. Here we show that culture medium alone containing Glutamine can generate milimolar of ammonia at 37 degrees in the absence of cells. In addition, we reveal that ammonia acts through the G protein-coupled receptor DRD3 (Dopamine receptor D3) to induce autophagy. At the same time, ammonia induces DRD3 degradation, which involves PIK3C3/VPS34-dependent pathways. Ammonia inhibits MTOR (mechanistic target of Rapamycin) activity and localization in cells, which is mediated by DRD3. Therefore, ammonia has dual roles in autophagy: one to induce autophagy through DRD3 and MTOR, the other to increase autophagosomal pH to inhibit autophagic flux. Our study not only adds a new sensing and output pathway for DRD3 that bridges ammonia sensing and autophagy induction, but also provides potential mechanisms for the clinical consequences of hyperammonemia in brain damage, neurodegenerative diseases and tumors.

  1. Dissociation and Mass Transfer Coefficients for Ammonia Volatilization Models

    Science.gov (United States)

    Process-based models are being used to predict ammonia emissions from manure sources, but their accuracy has not been fully evaluated for cattle manure. Laboratory trials were conducted to measure the dissociation and mass transfer coefficients for ammonia volatilization from media of buffered ammon...

  2. Crystal Structure of an Ammonia-Permeable Aquaporin.

    Directory of Open Access Journals (Sweden)

    Andreas Kirscht

    2016-03-01

    Full Text Available Aquaporins of the TIP subfamily (Tonoplast Intrinsic Proteins have been suggested to facilitate permeation of water and ammonia across the vacuolar membrane of plants, allowing the vacuole to efficiently sequester ammonium ions and counteract cytosolic fluctuations of ammonia. Here, we report the structure determined at 1.18 Å resolution from twinned crystals of Arabidopsis thaliana aquaporin AtTIP2;1 and confirm water and ammonia permeability of the purified protein reconstituted in proteoliposomes as further substantiated by molecular dynamics simulations. The structure of AtTIP2;1 reveals an extended selectivity filter with the conserved arginine of the filter adopting a unique unpredicted position. The relatively wide pore and the polar nature of the selectivity filter clarify the ammonia permeability. By mutational studies, we show that the identified determinants in the extended selectivity filter region are sufficient to convert a strictly water-specific human aquaporin into an AtTIP2;1-like ammonia channel. A flexible histidine and a novel water-filled side pore are speculated to deprotonate ammonium ions, thereby possibly increasing permeation of ammonia. The molecular understanding of how aquaporins facilitate ammonia flux across membranes could potentially be used to modulate ammonia losses over the plasma membrane to the atmosphere, e.g., during photorespiration, and thereby to modify the nitrogen use efficiency of plants.

  3. Bioluminescent bioreporter integrated circuit devices and methods for detecting ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, Michael L [Knoxville, TN; Paulus, Michael J [Knoxville, TN; Sayler, Gary S [Blaine, TN; Applegate, Bruce M [West Lafayette, IN; Ripp, Steven A [Knoxville, TN

    2007-04-24

    Monolithic bioelectronic devices for the detection of ammonia includes a microorganism that metabolizes ammonia and which harbors a lux gene fused with a heterologous promoter gene stably incorporated into the chromosome of the microorganism and an Optical Application Specific Integrated Circuit (OASIC). The microorganism is generally a bacterium.

  4. Crystal Structure of an Ammonia-Permeable Aquaporin.

    Science.gov (United States)

    Kirscht, Andreas; Kaptan, Shreyas S; Bienert, Gerd Patrick; Chaumont, François; Nissen, Poul; de Groot, Bert L; Kjellbom, Per; Gourdon, Pontus; Johanson, Urban

    2016-03-01

    Aquaporins of the TIP subfamily (Tonoplast Intrinsic Proteins) have been suggested to facilitate permeation of water and ammonia across the vacuolar membrane of plants, allowing the vacuole to efficiently sequester ammonium ions and counteract cytosolic fluctuations of ammonia. Here, we report the structure determined at 1.18 Å resolution from twinned crystals of Arabidopsis thaliana aquaporin AtTIP2;1 and confirm water and ammonia permeability of the purified protein reconstituted in proteoliposomes as further substantiated by molecular dynamics simulations. The structure of AtTIP2;1 reveals an extended selectivity filter with the conserved arginine of the filter adopting a unique unpredicted position. The relatively wide pore and the polar nature of the selectivity filter clarify the ammonia permeability. By mutational studies, we show that the identified determinants in the extended selectivity filter region are sufficient to convert a strictly water-specific human aquaporin into an AtTIP2;1-like ammonia channel. A flexible histidine and a novel water-filled side pore are speculated to deprotonate ammonium ions, thereby possibly increasing permeation of ammonia. The molecular understanding of how aquaporins facilitate ammonia flux across membranes could potentially be used to modulate ammonia losses over the plasma membrane to the atmosphere, e.g., during photorespiration, and thereby to modify the nitrogen use efficiency of plants.

  5. Method of treating ammonia-comprising waste water

    NARCIS (Netherlands)

    Van Loosdrecht, M.C.M.; Jetten, M.S.M.

    1998-01-01

    The invention relates to a method of treating ammonia-comprising waste water in which the bicarbonate ion is the counter ion of the ammonium ion present in the waste water. According to the invention half the ammonium is converted into nitrite, yielding an ammonia- and nitrite-containing solution, a

  6. Thermodynamic Model for the Ammonia-Water System

    DEFF Research Database (Denmark)

    Thomsen, Kaj; Rasmussen, Peter

    2000-01-01

    The ammonia-water system is described by the Extended UNIQUAC model, which is an electrolyte model, formed by combining the original UNIQUAC model, the Debye-Hückel law and the Soave-Redlich-Kwong equation of state. The model is limited to temperatures below the critical temperature of ammonia...

  7. An infrared spectroscopy method to detect ammonia in gastric juice.

    Science.gov (United States)

    Giovannozzi, Andrea M; Pennecchi, Francesca; Muller, Paul; Balma Tivola, Paolo; Roncari, Silvia; Rossi, Andrea M

    2015-11-01

    Ammonia in gastric juice is considered a potential biomarker for Helicobacter pylori infection and as a factor contributing to gastric mucosal injury. High ammonia concentrations are also found in patients with chronic renal failure, peptic ulcer disease, and chronic gastritis. Rapid and specific methods for ammonia detection are urgently required by the medical community. Here we present a method to detect ammonia directly in gastric juice based on Fourier transform infrared spectroscopy. The ammonia dissolved in biological liquid samples as ammonium ion was released in air as a gas by the shifting of the pH equilibrium of the ammonium/ammonia reaction and was detected in line by a Fourier transform infrared spectroscopy system equipped with a gas cell for the quantification. The method developed provided high sensitivity and selectivity in ammonia detection both in pure standard solutions and in a simulated gastric juice matrix over the range of diagnostic concentrations tested. Preliminary analyses were also performed on real gastric juice samples from patients with gastric mucosal injury and with symptoms of H. pylori infection, and the results were in agreement with the clinicopathology information. The whole analysis, performed in less than 10 min, can be directly applied on the sample without extraction procedures and it ensures high specificity of detection because of the ammonia fingerprint absorption bands in the infrared spectrum. This method could be easily used with endoscopy instrumentation to provide information in real time and would enable the endoscopist to improve and integrate gastroscopic examinations.

  8. Bioremediation of benzene-, MTBE- and ammonia-contaminated groundwater with pilot-scale constructed wetlands

    Energy Technology Data Exchange (ETDEWEB)

    Seeger, Eva M., E-mail: eva.seeger@ufz.de [Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig (Germany); Kuschk, Peter; Fazekas, Helga [Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig (Germany); Grathwohl, Peter [Center of Applied Geoscience, University of Tuebingen, Hoelderlinstr. 12, 72074 Tuebingen (Germany); Kaestner, Matthias [Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig (Germany)

    2011-12-15

    In this pilot-scale constructed wetland (CW) study for treating groundwater contaminated with benzene, MTBE, and ammonia-N, the performance of two types of CWs (a wetland with gravel matrix and a plant root mat) was investigated. Hypothesized stimulative effects of filter material additives (charcoal, iron(III)) on pollutant removal were also tested. Increased contaminant loss was found during summer; the best treatment performance was achieved by the plant root mat. Concentration decrease in the planted gravel filter/plant root mat, respectively, amounted to 81/99% for benzene, 17/82% for MTBE, and 54/41% for ammonia-N at calculated inflow loads of 525/603 mg/m{sup 2}/d, 97/112 mg/m{sup 2}/d, and 1167/1342 mg/m{sup 2}/d for benzene, MTBE, and ammonia-N. Filter additives did not improve contaminant depletion, although sorption processes were observed and elevated iron(II) formation indicated iron reduction. Bacterial and stable isotope analysis provided evidence for microbial benzene degradation in the CW, emphasizing the promising potential of this treatment technique. - Highlights: > BTEX compounds contaminated groundwater can be efficiently treated by CWs. > The removal efficiency depended on CW type, season and contaminant. > The plant root mat revealed better treatment results than the gravel filter CW. > Best results achieved by the plant root mat (99% benzene concentration decrease). > Stable isotope analysis and MPN indicated high benzene remediation potential. - Gravel bed constructed wetlands and a plant root mat system efficiently eliminated fuel hydrocarbons (benzene, MTBE) and ammonia-N from groundwater at a pilot-scale.

  9. Ammonia and hydrazine. Transition-metal-catalyzed hydroamination and metal-free catalyzed functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Bertrand, Guy [Univ. of California, San Diego, CA (United States)

    2012-06-29

    The efficient and selective preparation of organic molecules is critical for mankind. For the future, it is of paramount importance to find catalysts able to transform abundant and cheap feedstocks into useful compounds. Acyclic and heterocyclic nitrogen-containing derivatives are common components of naturally occurring compounds, agrochemicals, cosmetics, and pharmaceuticals; they are also useful intermediates in a number of industrial processes. One of the most widely used synthetic strategies, allowing the formation of an N-C bond, is the addition of an N-H bond across a carbon-carbon multiple bond, the so-called hydroamination reaction. This chemical transformation fulfills the principle of “green chemistry” since it ideally occurs with 100% atom economy. Various catalysts have been found to promote this reaction, although many limitations remain; one of the most prominent is the lack of methods that permit the use of NH3 and NH2NH2 as the amine partners. In fact, ammonia and hydrazine have rarely succumbed to homogeneous catalytic transformations. Considering the low cost and abundance of ammonia (136 million metric tons produced in 2011) and hydrazine, catalysts able to improve the reactivity and selectivity of the NH3- and NH2NH2-hydroamination reaction, and more broadly speaking the functionalization of these chemicals, are highly desirable. In the last funded period, we discovered the first homogeneous catalysts able to promote the hydroamination of alkynes and allenes with ammonia and the parent hydrazine. The key feature of our catalytic systems is that the formation of catalytically inactive Werner complexes is reversible, in marked contrast to most of the known ammonia and hydrazine transition metal complexes. This is due to the peculiar electronic properties of our neutral ancillary ligands, especially their strong donating capabilities. However, our catalysts currently require

  10. Scavenging of ammonia by raindrops in Saturn's great storm clouds

    Science.gov (United States)

    Delitsky, M. L.; Baines, Kevin

    2016-10-01

    Observations of the great Saturn storms of 2010-2011 by Cassini instruments showed a very large depletion in atmospheric ammonia. While dynamics will play a role, the very high solubility of ammonia in water may be another important contributor to ammonia depletion in storms. Ammonia exists in Earth's atmosphere and rainstorms dissolve ammonia to a great degree, leaving almost no NH3 in the atmosphere. Studies by Elperin et al (2011, 2013) show that scavenging of ammonia is greatest as a rainstorm starts and lessens as raindrops fall, tapering off to almost zero by the time the rain reaches the ground (Elperin et al 2009). Ammonia is reaching saturation as it dissolves in the aqueous solution. As concentration increases, NH3 is then converted to aqueous species (NH3)x.(H2O)y (Max and Chapados 2013).Ammonia has the highest solubility in water compared to all other gases in the Saturn atmosphere. The Henry's Law constant for NH3 in water is 60 M/atm at 25 C. For H2S, it is 0.001 M/atm. In Saturn storms, it is "raining UP": As water-laden storm clouds convectively rise, ammonia gas will be scavenged and go into solution to a great degree, whilst all the other gases remain mostly in the gas phase. Aqueous ammonia acts as an antifreeze: if ammonia is dissolved in water cloud droplets to the limit of its solubility, as water droplets rise, they can stay liquid (and continue to scavenge NH3) to well below their normal freezing point of 0 Celsius (273 K). The freezing point for a 30 wt % water-ammonia solution is ~189 K. The pressure level where T = 189 K is at 2.8 bars. The normal freezing point of water occurs at the 9 bar pressure level in Saturn's atmosphere. 2.8 bars occurs at the -51 km altitude (below the 1 bar level). 9 bars is at the -130 km level: a difference of 79 km. A water droplet containing 30 wt% NH3 can move upwards from 9 bars to 2.8 bars (79 km) and still remain liquid, only freezing above that altitude. Calculations by the E-AIM model show that ammonia

  11. Alkaline Ammonia Electrolysis on Electrodeposited Platinum for Controllable Hydrogen Production.

    Science.gov (United States)

    Gwak, Jieun; Choun, Myounghoon; Lee, Jaeyoung

    2016-02-19

    Ammonia is beginning to attract a great deal of attention as an alternative energy source carrier, because clean hydrogen can be produced through electrolytic processes without the emission of COx . In this study, we deposited various shapes of Pt catalysts under potentiostatic mode; the electrocatalytic oxidation behavior of ammonia using these catalysts was studied in alkaline media. The electrodeposited Pt was characterized by both qualitative and quantitative analysis. To discover the optimal structure and the effect of ammonia concentration, the bulk pH value, reaction temperature, and applied current of ammonia oxidation were investigated using potential sweep and galvanostatic methods. Finally, ammonia electrolysis was conducted using a zero-gap cell, producing highly pure hydrogen with an energy efficiency over 80 %.

  12. Hydrolyzabilities of different corn stover fractions after aqueous ammonia pretreatment.

    Science.gov (United States)

    Sun, Zongping; Ge, Xiaoyan; Xin, Donglin; Zhang, Junhua

    2014-02-01

    The effect of aqueous ammonia pretreatment on the hydrolysis of different corn stover fractions (rind, husk, leaf, and pith) by xylanase (XYL) with cellulases (CELs) was evaluated. The aqueous ammonia pretreatment had excellent delignification ability (above 66%) for different corn stover fractions. The corn rind exhibited the lowest susceptibility to aqueous ammonia pretreatment. The pretreated rind showed the lowest hydrolyzability by CEL and XYL, which was supported by a high content of crystalline cellulose in the hydrolyzed residues of rind, as confirmed by X-ray diffraction (XRD). With the addition of 1 mg XYL/g dry matter, a high glucose yield (above 90%) could be obtained from the pretreated rind by CEL. The results revealed that a high hydrolyzate yield of corn rind after aqueous ammonia pretreatment could be obtained with 1 mg xylanase/g dry matter, showing that aqueous ammonia pretreatment and xylanase addition to cellulases have great potential for the efficient hydrolysis of corn stover without previous fractionation.

  13. Moisture insensitive adsorption of ammonia on resorcinol-formaldehyde resins.

    Science.gov (United States)

    Seredych, Mykola; Ania, Conchi; Bandosz, Teresa J

    2016-03-15

    Phenolic-formaldehyde resins aged at 85, 90 and 95°C were used as ammonia adsorbents at dynamic conditions in dry and moist air. To avoid pressure drops 10% bentonite was added as a binder. The initial and hybrid materials (before and after ammonia adsorption) were extensively characterized from the point of view of their porosity and surface chemistry. The results showed that the addition of the binder had various effects on materials' properties depending on the chemistry of their surface groups. When the phenolic acidic groups were predominant, the largest increase in surface acidity upon the addition of the binder was found. It was linked to the exfoliation of bentonite by polar moieties of the resins, which made acidic groups from aluminosilicate layers available for ammonia adsorption. On this sample, a relatively high amount of ammonia was strongly adsorbed in dry conditions. Insensitivity to moisture is a significant asset of ammonia adsorbents.

  14. Safety assessment of ammonia as a transport fuel

    DEFF Research Database (Denmark)

    Duijm, N.J.; Markert, Frank; Paulsen, Jette Lundtang

    2005-01-01

    of transport of ammonia to the refuelling stations and safety of the activities at the refuelling station (unloading and refuelling). Comparisons are made between the safety of using ammonia and the safety of otherexisting or alternative fuels. The conclusion is that the hazards in relation to ammonia need......This report describes the safety study performed as part of the EU supported project “Ammonia Cracking for Clean Electric Power Technology” The study addresses the following activities: safety of operation of the ammonia-powered vehicle under normal andaccident (collision) conditions, safety...... to be controlled by a combination of technical and regulatory measures. The most important requirements are: - Advanced safety systems in the vehicle -Additional technical measures and regulations are required to avoid releases in maintenance workshops and unauthorised maintenance on the fuel system. - Road...

  15. Ammonia emissions in Europe, part I: Development of a dynamical ammonia emission inventory

    Science.gov (United States)

    Backes, Anna; Aulinger, Armin; Bieser, Johannes; Matthias, Volker; Quante, Markus

    2016-04-01

    Nitrogen input from agricultural ammonia emissions into the environment causes numerous environmental and health problems. The purpose of this study is to present and evaluate an improved ammonia emission inventory based on a dynamical temporal parameterization suitable to compare and assess ammonia abatement strategies. The setup of the dynamical time profile (DTP) consists of individual temporal profiles for ammonia emissions, calculated for each model grid cell, depending on temperature, crop type, fertilizer and manure application, as well as on local legislation. It is based on the method of Skjøth et al., 2004 and Gyldenkærne et al., 2005. The method has been modified to cover the study area and to improve the performance of the emission model. To compare the results of the dynamical approach with the results of the static time profile (STP) the ammonia emission parameterizations have been implemented in the SMOKE for Europe emission model. Furthermore, the influence on secondary aerosol formation in the North Sea region and possible changes triggered through the use of a modified temporal distribution of ammonia emissions were analysed with the CMAQ chemistry transport model. The results were evaluated with observations of the European Monitoring and Evaluation Programme (EMEP). The correlation coefficient of NH3 improved significantly for 12 out of 16 EMEP measurement stations and an improvement in predicting the Normalized Mean Error can be seen for particulate NH4+ and NO3-. The prediction of the 95th percentile of the daily average concentrations has improved for NH3, NH4+ and NO3-. The NH3 concentration modelled with the STP is 157% higher in winter, and about 22% lower in early summer than the one modelled with the new DTP. Consequently, the influence of the DTP on the formation of secondary aerosols is particularly noticeable in winter, when the PM2.5 concentration is 25% lower in comparison to the use of STP for temporal disaggregation. Besides

  16. Ammonia emissions in agriculture: Proceedings of the First international ammonia conference 19-21 March 2007, Ede, The Netherlands

    NARCIS (Netherlands)

    Monteny, G.J.; Hartung, J.

    2007-01-01

    Ammonia emissions is an important topic in many countries with animal production, since it contributes to environmental and health problems. Strategies and measures to reduce ammonia emission are getting increasing attention in national and international legislation. The focus of this publication is

  17. Ammonia synthesis. Ammonia synthesis by N₂ and steam electrolysis in molten hydroxide suspensions of nanoscale Fe₂O₃.

    Science.gov (United States)

    Licht, Stuart; Cui, Baochen; Wang, Baohui; Li, Fang-Fang; Lau, Jason; Liu, Shuzhi

    2014-08-08

    The Haber-Bosch process to produce ammonia for fertilizer currently relies on carbon-intensive steam reforming of methane as a hydrogen source. We present an electrochemical pathway in which ammonia is produced by electrolysis of air and steam in a molten hydroxide suspension of nano-Fe2O3. At 200°C in an electrolyte with a molar ratio of 0.5 NaOH/0.5 KOH, ammonia is produced at 1.2 volts (V) under 2 milliamperes per centimeter squared (mA cm(-2)) of applied current at coulombic efficiency of 35% (35% of the applied current results in the six-electron conversion of N2 and water to ammonia, and excess H2 is cogenerated with the ammonia). At 250°C and 25 bar of steam pressure, the electrolysis voltage necessary for 2 mA cm(-2) current density decreased to 1.0 V.

  18. Innovative bioelectrochemical-anaerobic-digestion integrated system for ammonia recovery and bioenergy production from ammonia-rich residues

    DEFF Research Database (Denmark)

    Zhang, Yifeng; Angelidaki, Irini

    2015-01-01

    (SMRC) and a continuous stirred tank reactor (CSTR), to prevent ammonia toxicity during anaerobic digestion by in-situ ammonia recovery and electricity production (Figure 1). In batch experiment, the ammonia concentration in the CSTR decreased from 6 to 0.7 g-N/L with an average recovery rate of 0.18 g......-N/L(CSTR)/d. Meanwhile, a maximum power density of 0.71±0.5 W/m2 was produced (10 Ω). Both current driven NH4+ migration and free NH3 diffusion were identified as the mechanisms responsible for the ammonia transportation. With an increase in initial ammonia concentration and a decrease in external resistance, the SMRC...

  19. Ammonia Thermometry of Star Forming Galaxies

    CERN Document Server

    Mangum, Jeffrey G; Henkel, Christian; Menten, Karl M; MacGregor, Meredith; Svoboda, Brian E; Schinnerer, Eva

    2013-01-01

    With a goal toward deriving the physical conditions in external galaxies, we present a study of the ammonia (NH$_3$) emission and absorption in a sample of star forming systems. Using the unique sensitivities to kinetic temperature afforded by the excitation characteristics of several inversion transitions of NH$_3$, we have continued our characterization of the dense gas in star forming galaxies by measuring the kinetic temperature in a sample of 23 galaxies and one galaxy offset position selected for their high infrared luminosity. We derive kinetic temperatures toward 13 galaxies, 9 of which possess multiple kinetic temperature and/or velocity components. Eight of these galaxies exhibit kinetic temperatures $>100$ K, which are in many cases at least a factor of two larger than kinetic temperatures derived previously. Furthermore, the derived kinetic temperatures in our galaxy sample, which are in many cases at least a factor of two larger than derived dust temperatures, point to a problem with the common a...

  20. Towards an ammonia-mediated hydrogen economy?

    DEFF Research Database (Denmark)

    Christensen, Claus H.; Johannessen, Tue; Sørensen, Rasmus Zink;

    2006-01-01

    Materialization of a hydrogen economy could provide a solution to significant global challenges, In particular. the possibility of improving the efficiency and simultaneously minimizing the environmental impact of energy conversion processes, together with the opportunity to reduce the dependency...... of fossil fuels, are main drivers for the currently increasing research and development efforts. However. significant technological breakthroughs are necessary for making a hydrogen economy feasible. In particular, it is necessary to develop appropriate hydrogen storage and transportation technologies....... Recently, metal ammine salts were proposed as safe, reversible. high-density and low-cost hydrogen carriers. Here, we discuss how this development could provide a platform for using ammonia as a fuel for the hydrogen economy, We do that by comparing various possible hydrogen carriers with respect to energy...

  1. Ammonia-Free NOx Control System

    Energy Technology Data Exchange (ETDEWEB)

    S. Wu; Z. Fan; R. Herman

    2004-03-31

    Research is being conducted under United States Department of Energy (DOE) Contract DEFC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia. This report describes the work performed during the January 1 to March 31, 2004 time period.

  2. Ammonia-Free NOx Control System

    Energy Technology Data Exchange (ETDEWEB)

    S. Wu

    2003-12-31

    Research is being conducted under United States Department of Energy (DOE) Contract DEFC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia. This report describes the work performed during the October 1 to December 31, 2003 time period.

  3. Multipurpose Compound

    Science.gov (United States)

    1983-01-01

    Specially formulated derivatives of an unusual basic compound known as Alcide may be the answer to effective treatment and prevention of the disease bovine mastitis, a bacterial inflammation of a cow's mammary gland that results in loss of milk production and in extreme cases, death. Manufactured by Alcide Corporation the Alcide compound has killed all tested bacteria, virus and fungi, shortly after contact, with minimal toxic effects on humans or animals. Alcide Corporation credits the existence of the mastitis treatment/prevention products to assistance provided the company by NERAC, Inc.

  4. Nitrogen-13-labeled ammonia for myocardial imaging

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, W.F.; Fill, H.R.; Harper, P.V.

    1977-01-01

    Cyclotron-produced nitrogen-13 (half-life 10 min), as labeled ammonia (/sup 13/NH/sub 4//sup +/), has been evaluated as a myocardial perfusion imaging agent. The regional myocardial uptake of /sup 13/NH/sub 4//sup +/ has been shown to be proportional to regional tissue perfusion in animal studies. Intravenously administered /sup 13/NH/sub 4//sup +/ is rapidly cleared from the circulation, being extracted by the liver (15 percent), lungs, myocardium (2 percent--4 percent), brain, kidney, and bladder. Myocardial ammonia is metabolized mainly to glutamine via the glutamine synthetase pathway. Pulmonary uptake is substantial, but usually transient, except in smokers where clearance may be delayed. The positron annihilation irradiation (511 keV) of /sup 13/N may be imaged with a scintillation camera, using either a specially designed tungsten collimator or a pinhole collimator. After early technical problems with collimation and the production method of /sup 13/NH/sub 4//sup +/ were overcome, reproducible high quality myocardial images were consistently obtained. The normal myocardial image was established to be of a homogeneous ''doughnut'' configuration. Imaging studies performed in patients with varying manifestations of ischemic and valvular heart disease showed a high incidence of localized perfusion defects, especially in patients with acute myocardial infarction. Sequential studies at short intervals in patients with acute infarction showed correlation between alterations in regional perfusion and the clinical course of the patient. It is concluded that myocardial imaging with /sup 13/NH/sub 4//sup +/ and a scintillation camera provides a valid and noninvasive means of assessing regional myocardial perfusion. This method is especially suitable for sequential studies of acute cardiac patients at short intervals. Coincidence imaging of the 511 keV annihilation irradiation provides a tomographic and potentially quantitative assessment of the

  5. Efficient and Safe Chemical Gas Generators with Nanocomposite Reactive Materials

    Science.gov (United States)

    2015-11-30

    ammonia borane has been developed that involves the reaction of mechanically alloyed Al·Mg powder with water as a source of heat for ammonia borane...Edward L. Dreizin, Evgeny Shafirovich. Hydrogen generation from ammonia borane and water through combustion reactions with mechanically alloyed... Synthesis , 21 - 24 October 2013, South Padre Island, TX, p. 211. Rodriguez, D., Machado, M., Shafirovich, E., and Dreizin, E.L., “Gas Generating

  6. Safety assessment of ammonia as a transport fuel

    Energy Technology Data Exchange (ETDEWEB)

    Duijm, N.J.; Markert, F.; Lundtang paulsen, Jette

    2005-02-01

    This report describes the safety study performed as part of the EU supported project 'Ammonia Cracking for Clean Electric Power Technology' The study addresses the following activities: safety of operation of the ammonia-powered vehicle under normal and accident (collision) conditions, safety of transport of ammonia to the refuelling stations and safety of the activities at the refuelling station (unloading and refuelling). Comparisons are made between the safety of using ammonia and the safety of other existing or alternative fuels. The conclusion is that the hazards in relation to ammonia need to be controlled by a combination of technical and regulatory measures. The most important requirements are: - Advanced safety systems in the vehicle - Additional technical measures and regulations are required to avoid releases in maintenance workshops and unauthorised maintenance on the fuel system - Road transport of ammonia to refuelling stations in refrigerated form - Sufficient safety zones between refuelling stations and residential or otherwise public areas. When these measures are applied, the use of ammonia as a transport fuel wouldnt cause more risks than currently used fuels (using current practice). (au)

  7. Effect of ammonia stress on nitrogen metabolism of Ceratophyllum demersum.

    Science.gov (United States)

    Gao, Jingqing; Li, Linshuai; Hu, Zhiyuan; Yue, Hui; Zhang, Ruiqin; Xiong, Zhiting

    2016-01-01

    The objective of the present study was to determine the effect of total ammonia N concentration and pH on N metabolism of Ceratophyllum demersum and to evaluate stress as a result of inorganic N enrichment in the water column on submerged macrophytes. Carefully controlled pH values distinguished between the effects of un-ionized NH3 and ionized NH4(+). The results showed that the most obvious consequence of ammonia addition was an overall increase in ammonia content and decrease in nitrate content in all tissues of fertilized plants. The activities of nitrate reductase and glutamine synthetase were inhibited by long-term ammonia addition. At the same time, ammonia addition significantly decreased soluble protein content and increased free amino acid content in all treatments. Another clear effect of ammonia addition was a decrease in carbon reserves. Therefore, the authors concluded that increased ammonia availability could affect plant survival and lead to a decline in C. demersum proliferation through a decrease in their carbon reserves. This interaction between N and C metabolism helps to explain changes in benthic vegetation as a result of steadily increasing coastal water eutrophication.

  8. Direct Measurements of the Surface-Atmosphere Exchange of Ammonia

    Science.gov (United States)

    Tevlin, A.; Murphy, J. G.; Wentworth, G.; Gregoire, P.

    2012-12-01

    As the dominant atmospheric base, ammonia plays an important role in the formation and growth of inorganic aerosols. Surface-atmosphere exchange of ammonia has been observed to occur as a bidirectional flux governed by the relative magnitudes of atmospheric gas phase concentration and a temperature-dependent surface compensation point. In order to better characterise the links between gas-particle and surface-atmosphere exchanges, more direct measurements of these exchanges are necessary. Eddy Covariance (EC) can provide the most direct surface-atmosphere flux measurements, but its requirement for high frequency data combined with the reactive nature of ammonia have limited its application for this species. In order to address this lack, an investigation into the instrumental sensitivity and time response requirements for EC ammonia flux measurements was carried out using a Quantum Cascade-Tunable Infrared Laser Differential Absorption Spectrometer (QC-TILDAS) capable of measuring ammonia concentration at 10 Hz. Time response was additionally improved through the use of a heated sample line and custom glass inlet, and the system was deployed over a short grass field in rural Ontario. The ammonia measurements were used along with three dimensional sonic anemometer wind speed data to calculate EC ammonia fluxes. When combined with simultaneous measurements of the inorganic composition of gas and particle phases made by Ambient Ion Monitor - Ion Chromatography (AIM-IC), these flux measurements can provide insight into the links between gas-particle and surface-atmosphere exchange.

  9. Arterial ammonia levels in the management of fulminant liver failure

    Directory of Open Access Journals (Sweden)

    Curry S

    2011-06-01

    Full Text Available Previous studies have suggested that an arterial ammonia level greater than 150 mmol/L is highly sensitive for predicting subsequent development of cerebral edema in patients with fulminant liver failure. We performed a prospective cohort study to confirm this relationship. We enrolled 22 consecutive patients who presented to our transplant hepatology service with grade 3-4 encephalopathy associated with fulminant liver failure. All patients underwent placement of an intraparenchymal ICP monitor, and every 12 hourly arterial ammonia levels. The prevalence of intracranial hypertension (IHTN in our population was 95% (21/22 patients, with 82 discrete episodes recorded. The sensitivity of arterial ammonia levels to predict the onset of IHTN was 62% (95% CI: 40.8 to 79.3 at a cut point of 150 mmol/L. Arterial ammonia levels preceding the first intracranial hypertension event were less than 150 mmol/L in 8 of 21 patients (39%. Fifty nine of 82 episodes of IHTN (73% occurred when arterial ammonia levels were less than 150 mmol/L. We conclude that the arterial ammonia level is not useful in making decisions regarding management related to cerebral edema in patients with fulminant liver failure. In fact, since almost all our study patients with grade III or IV encephalopathy secondary to fulminant liver failure went on to develop intracranial hypertension, our study supports the contention that all such patients might benefit from ICP monitoring regardless of arterial ammonia levels.

  10. SIRT5 regulation of ammonia-induced autophagy and mitophagy.

    Science.gov (United States)

    Polletta, Lucia; Vernucci, Enza; Carnevale, Ilaria; Arcangeli, Tania; Rotili, Dante; Palmerio, Silvia; Steegborn, Clemens; Nowak, Theresa; Schutkowski, Mike; Pellegrini, Laura; Sansone, Luigi; Villanova, Lidia; Runci, Alessandra; Pucci, Bruna; Morgante, Emanuela; Fini, Massimo; Mai, Antonello; Russo, Matteo A; Tafani, Marco

    2015-01-01

    In liver the mitochondrial sirtuin, SIRT5, controls ammonia detoxification by regulating CPS1, the first enzyme of the urea cycle. However, while SIRT5 is ubiquitously expressed, urea cycle and CPS1 are only present in the liver and, to a minor extent, in the kidney. To address the possibility that SIRT5 is involved in ammonia production also in nonliver cells, clones of human breast cancer cell lines MDA-MB-231 and mouse myoblast C2C12, overexpressing or silenced for SIRT5 were produced. Our results show that ammonia production increased in SIRT5-silenced and decreased in SIRT5-overexpressing cells. We also obtained the same ammonia increase when using a new specific inhibitor of SIRT5 called MC3482. SIRT5 regulates ammonia production by controlling glutamine metabolism. In fact, in the mitochondria, glutamine is transformed in glutamate by the enzyme glutaminase, a reaction producing ammonia. We found that SIRT5 and glutaminase coimmunoprecipitated and that SIRT5 inhibition resulted in an increased succinylation of glutaminase. We next determined that autophagy and mitophagy were increased by ammonia by measuring autophagic proteolysis of long-lived proteins, increase of autophagy markers MAP1LC3B, GABARAP, and GABARAPL2, mitophagy markers BNIP3 and the PINK1-PARK2 system as well as mitochondrial morphology and dynamics. We observed that autophagy and mitophagy increased in SIRT5-silenced cells and in WT cells treated with MC3482 and decreased in SIRT5-overexpressing cells. Moreover, glutaminase inhibition or glutamine withdrawal completely prevented autophagy. In conclusion we propose that the role of SIRT5 in nonliver cells is to regulate ammonia production and ammonia-induced autophagy by regulating glutamine metabolism.

  11. Ice nucleation of ammonia gas exposed montmorillonite mineral dust particles

    Directory of Open Access Journals (Sweden)

    A. Salam

    2007-01-01

    Full Text Available The ice nucleation characteristics of montmorillonite mineral dust aerosols with and without exposure to ammonia gas were measured at different atmospheric temperatures and relative humidities with a continuous flow diffusion chamber. The montmorillonite particles were exposed to pure (100% and diluted ammonia gas (25 ppm at room temperature in a stainless steel chamber. There was no significant change in the mineral dust particle size distribution due to the ammonia gas exposure. 100% pure ammonia gas exposure enhanced the ice nucleating fraction of montmorillonite mineral dust particles 3 to 8 times at 90% relative humidity with respect to water (RHw and 5 to 8 times at 100% RHw for 120 min exposure time within our experimental conditions. The percentages of active ice nuclei were 2 to 9 times higher at 90% RHw and 2 to 13 times higher at 100% RHw in 25 ppm ammonia exposed montmorillonite compared to unexposed montmorillonite. All montmorillonite particles are more efficient as ice nuclei with increasing relative humidities and decreasing temperatures. The activation temperature of montmorillonite exposed to 100% pure ammonia was 12°C higher than for unexposed montmorillonite particles at 90% RHw and 10°C higher at 100% RHw. In the 25 ppm ammonia exposed montmorillonite experiments, the activation temperature was 7°C warmer than unexposed montmorillonite at 100% RHw. Degassing does not reverse the ice nucleating ability of ammonia exposed montmorillonite mineral dust particles. This is the first experimental evidence that ammonia gas exposed montmorillonite mineral dust particles can enhance its activation as ice nuclei and that the activation can occur at temperatures warmer than –10°C where natural atmospheric ice nuclei are very scarce.

  12. The partial reduction of electron-deficient pyrroles: procedures describing both Birch (Li/NH3) and ammonia-free (Li/DBB) conditions.

    Science.gov (United States)

    Donohoe, Timothy J; Thomas, Rhian E

    2007-01-01

    The partial reduction of electron-deficient pyrroles using either Birch (Li/NH(3)) or ammonia-free (Li/di-tert-butyl biphenyl) conditions allows formation of pyrroline compounds in good yield and, when combined with a reductive alkylation or similar approach, leads to highly functionalized, synthetically useful compounds. This methodology has been proven in the syntheses of several complex natural products, all of which show interesting biological activity. This protocol describes in detail the following stages of the partial reduction procedure: formation of the reducing solution, partial reduction of the pyrrole compound and finally quench of the resulting anion/dianion using either protonating agents or an aldehyde. The ammonia-free conditions described herein are particularly useful for reactions requiring the use of reactive electrophiles, such as acid chlorides or enolizable aldehydes, which are incompatible with the standard Birch reduction conditions. The reaction procedure for the ammonia Birch reduction (procedure A) takes about 9.5 h to complete. Those described for the ammonia-free reductions, procedure B and procedure C, can be expected to take approximately 33 and 8 h, respectively.

  13. Detection of Widespread Hot Ammonia in the Galactic Center

    OpenAIRE

    Mills, Elisabeth A. C.; Morris, Mark R.

    2013-01-01

    We present the detection of metastable inversion lines of ammonia from energy levels high above the ground state. We detect these lines in both emission and absorption toward fifteen of seventeen positions in the central 300 parsecs of the Galaxy. In total, we observe seven metastable transitions of ammonia: (8,8), (9,9), (10,10), (11,11), (12,12), (13,13) and (15,15), with energies (in Kelvins) ranging from 680 to 2200 K. We also map emission from ammonia (8,8) and (9,9) in two clouds in the...

  14. Catalytic synthesis of ammonia using vibrationally excited nitrogen

    DEFF Research Database (Denmark)

    Henriksen, Niels Engholm; Billing, Gert D.; Hansen, Flemming Yssing

    1992-01-01

    In a previous study we have considered the catalytic synthesis of ammonia in the presence of vibrationally excited nitrogen. The distribution over vibrational states was assumed to be maintained during the reaction, and it was shown that the yield of ammonia increased considerably compared...... to that from conventional synthesis. In the present study the nitrogen molecules are only excited at the inlet of a plug flow reactor, and the importance of vibrational relaxation is investigated. We show that vibrational excitation can give an enhanced yield of ammonia also in the situation where vibrational...

  15. Protective effect of immobilized ammonia oxidizers and phenol-degrading bacteria on nitrification in ammonia- and phenol-containing wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Morita, M.; Watanabe, A. [Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), Chiba (Japan); Kudo, N.; Shinozaki, H. [Materials Science Engineering, Tokyo Denki University, Tokyo (Japan); Uemoto, H.

    2007-12-15

    Phenol present in wastewaters from various industries has an inhibitory effect on nitrification even at low concentrations. Hence, the biological treatment of wastewater containing both phenol and ammonia involves a series of treatment steps. It is difficult to achieve nitrification capability in an activated sludge system that contains phenol at concentrations above the inhibitory level. Batch treatment of wastewater containing various concentrations of phenol showed that the ammonia oxidation capability of suspended Nitrosomonas europaea cells, an ammonia oxidizer, was completely inhibited in the presence of more than 5.0 mg/L phenol. To protect the ammonia oxidizer from the inhibitory effect of phenol and to achieve ammonia oxidation capability in the wastewater containing phenol at concentrations above the inhibitory level, a simple bacterial consortium composed of an ammonia oxidizer (N. europaea) and a phenol-degrading bacterial strain (Acinetobacter sp.) was used. Ammonia oxidation did not occur in the presence of phenol at concentrations above the inhibitory level when suspended or immobilized N. europaea and Acinetobacter sp. cells were used in batch treatment. Following the acclimatization of the immobilized cells, accumulation of nitrite was observed, even when the wastewater contained phenol at concentrations above the inhibitory level. These results showed that immobilization was effective in protecting N. europaea cells from the inhibitory effect of phenol present in the wastewater. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  16. Submersible microbial desalination cell for simultaneous ammonia recovery and electricity production from anaerobic reactors containing high levels of ammonia.

    Science.gov (United States)

    Zhang, Yifeng; Angelidaki, Irini

    2015-02-01

    High ammonia concentration in anaerobic reactors can seriously inhibit the anaerobic digestion process. In this study, a submersible microbial desalination cell (SMDC) was developed as an innovative method to lower the ammonia level in a continuous stirred tank reactor (CSTR) by in situ ammonia recovery and electricity production. In batch experiment, the ammonia concentration in the CSTR decreased from 6 to 0.7 g-N/L during 30 days, resulting in an average recovery rate of 80 g-N/m(2)/d. Meanwhile, a maximum power density of 0.71±0.5 W/m(2) was generated at 2.85 A/m(2). Both current driven NH4(+) migration and free NH3 diffusion were identified as the mechanisms responsible for the ammonia transportation. With an increase in initial ammonia concentration and a decrease in external resistance, the SMDC performance was enhanced. In addition, the coexistence of other cations in CSTR or cathode had no negative effect on the ammonia transportation.

  17. 46 CFR 111.105-32 - Bulk liquefied flammable gas and ammonia carriers.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Bulk liquefied flammable gas and ammonia carriers. 111... gas and ammonia carriers. (a) Each vessel that carries bulk liquefied flammable gases or ammonia as a.... (2) The term “gas-dangerous” does not include the weather deck of an ammonia carrier. (c)...

  18. New efficient catalyst for ammonia synthesis: barium-promoted cobalt on carbon

    DEFF Research Database (Denmark)

    Hagen, Stefan; Barfod, Rasmus; Fehrmann, Rasmus

    2002-01-01

    Barium-promoted cobalt catalysts supported on carbon exhibit higher ammonia activities at synthesis temperatures than the commercial, multipromoted iron catalyst and also a lower ammonia......Barium-promoted cobalt catalysts supported on carbon exhibit higher ammonia activities at synthesis temperatures than the commercial, multipromoted iron catalyst and also a lower ammonia...

  19. Ammonia removal from an aqueous solution and method for the production of a fertilizer material

    NARCIS (Netherlands)

    Kelder, E.M.; Ursem, W.N.J.; Roos, R.A.; Marijnissen, J.C.M.

    2011-01-01

    The invention provides method for the removal of ammonia from air and converting the ammonia in a fertilizer material, comprising (a) contacting at least part of the air with an aqueous liquid, wherein the aqueous liquid is a solvent for ammonia, to provide an ammonia containing aqueous liquid,and(b

  20. Intermetallic Compounds

    Science.gov (United States)

    Takagiwa, Y.; Matsuura, Y.; Kimura, K.

    2014-06-01

    We have focused on the binary narrow-bandgap intermetallic compounds FeGa3 and RuGa3 as thermoelectric materials. Their crystal structure is FeGa3-type (tetragonal, P42/ mnm) with 16 atoms per unit cell. Despite their simple crystal structure, their room temperature thermal conductivity is in the range 4-5-W-m-1-K-1. Both compounds have narrow-bandgaps of approximately 0.3-eV near the Fermi level. Because their Seebeck coefficients are quite large negative values in the range 350-FeGa3 and RuGa3 as n and p-type materials. The dimensionless figure of merit, ZT, was significantly improved by substitution of Sn for Ga in FeGa3 (electron-doping) and by substitution of Zn for Ga in RuGa3 (hole-doping), mainly as a result of optimization of the electronic part, S 2 σ.

  1. Synthesis and Antitussive Effect of New Hydantoin Compounds

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qun-li; SONG Li-jun; WANG En-si

    2013-01-01

    A series of new hydantoin compounds was synthesized with 3-bromo phenylacetic acid and 3,4-dimethylbromobenzene as starting material,7-bromo-2-tetralone and 2-bromo-5,6,8,9-tetrahydro-7-benzocycloheptenone as intermediate and Ullmann reaction,Suzuki reaction and Bucherer-Berg's reaction as key steps.The structures of the key intermediate and target compounds were confirmed by 1H NMR,13C NMR,IR and MS.Bioactivity research showed that target compounds 6a,6c,6d,6e and 15i had significant antitussive effect on the ammonia-induced cough of mice.

  2. Compound odontoma

    Directory of Open Access Journals (Sweden)

    Monica Yadav

    2012-01-01

    Full Text Available Odontomas have been extensively reported in the dental literature, and the term refers to tumors of odontogenic origin. Though the exact etiology is still unknown, the postulated causes include: local trauma, infection, inheritance and genetic mutation. The majority of the lesions are asymptomatic; however, may be accompanied with pain and swelling as secondary complaints in some cases. Here, we report a case of a compound odontome in a 14 year old patient.

  3. Organic Compounds

    Science.gov (United States)

    Shankland, Kenneth

    For many years, powder X-ray diffraction was used primarily as a fingerprinting method for phase identification in the context of molecular organic materials. In the early 1990s, with only a few notable exceptions, structures of even moderate complexity were not solvable from PXRD data alone. Global optimisation methods and highly-modified direct methods have transformed this situation by specifically exploiting some well-known properties of molecular compounds. This chapter will consider some of these properties.

  4. Nematocyst discharge in Pelagia noctiluca (Cnidaria, Scyphozoa) oral arms can be affected by lidocaine, ethanol, ammonia and acetic acid.

    Science.gov (United States)

    Morabito, Rossana; Marino, Angela; Dossena, Silvia; La Spada, Giuseppa

    2014-06-01

    Nematocyst discharge and concomitant delivery of toxins is triggered to perform both defence and predation strategies in Cnidarians, and may lead to serious local and systemic reactions in humans. Pelagia noctiluca (Cnidaria, Scyphozoa) is a jellyfish particularly abundant in the Strait of Messina (Italy). After accidental contact with this jellyfish, not discharged nematocysts or even fragments of tentacles or oral arms may tightly adhere to the human skin and, following discharge, severely increase pain and the other adverse consequences of the sting. The aim of the present study is to verify if the local anesthetic lidocaine and other compounds, like alcohols, acetic acid and ammonia, known to provide pain relief after jellyfish stings, may also affect in situ discharge of nematocysts. Discharge was induced by a combined physico-chemical stimulation of oral arms by chemosensitizers (such as N-acetylated sugars, aminoacids, proteins and nucleotides), in the presence or absence of 1% lidocaine, 70% ethanol, 5% acetic acid or 20% ammonia, followed by mechanical stimulation by a non-vibrating test probe. The above mentioned compounds failed to induce discharge per se, and dramatically impaired the chemosensitizer-induced discharge response. We therefore suggest that prompt local treatment of the stung epidermis with lidocaine, acetic acid, ethanol and ammonia may provide substantial pain relief and help in reducing possible harmful local and systemic adverse reaction following accidental contact with P. noctiluca specimens.

  5. 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.

  6. IRIS Toxicological Review of Ammonia - Noncancer Inhalation (Final Report)

    Science.gov (United States)

    The U.S. Environmental Protection Agency's (USEPA) has finalized the Integrated Risk Information System (IRIS) Assessment of Ammonia (Noncancer Inhalation). This assessment addresses the potential noncancer human health effects from long-term inhalation exposure to ammon...

  7. Predicting catalysis: Understanding ammonia synthesis from first-principles calculations

    DEFF Research Database (Denmark)

    Hellmann, A.; Baerends, E.J.; Biczysko, M.

    2006-01-01

    . Furthermore, our studies provide new insight into several related fields, for instance, gas-phase and electrochemical ammonia synthesis. The success of predicting the outcome of a catalytic reaction from first-principles calculations supports our point of view that, in the future, theory will be a fully......Here, we give a full account of a large collaborative effort toward an atomic-scale understanding of modern industrial ammonia production over ruthenium catalysts. We show that overall rates of ammonia production can be determined by applying various levels of theory (including transition state...... for any given point along an industrial reactor, and the kinetic results can be integrated over the catalyst bed to determine the industrial reactor yield. We find that, given the present uncertainties, the rate of ammonia production is well-determined directly from our atomic-scale calculations...

  8. Electrolytes and Electrodes for Electrochemical Synthesis of Ammonia

    DEFF Research Database (Denmark)

    Lapina, Alberto

    to evaluate their applicability to electrochemical synthesis of ammonia. First a number of potential electrolytes are investigated in the temperature range 25-400°C in order to find a proton conductor with a conductivity higher than 10-4 S/cm in dry atmosphere (pH2O ... effective energy storage solutions. Production of synthetic fuels (e.g. ammonia) is a promising possibility. Ammonia (NH3) can be an interesting energy carrier, thanks to its high energy density and the existence of well developed storage and transportation technologies. However the present-day production...... technology is based on the Haber-Bosch process, which is energy intensive and requires large-scale plants. One possible way to produce ammonia from sustainable electricity, nitrogen and hydrogen/water is using an electrochemical cell. This thesis studies a number of electrolytes and electrocatalysts...

  9. Computational Design of New Materials for Ammonia Storage

    DEFF Research Database (Denmark)

    Jensen, Peter Bjerre; Quaade, Ulrich

    by using the available operators,which are based on a combination of chemical knowledge and random events.The initial experimental tests of the identified candidates showed promisingresults, but did also reveal that the materials can be challenging to synthesize,and might degrade during ammonia desorption......Many renewable energy technologies are currently being developed, but most have the major drawback, that the energy is not generated when needed, and storage of the energy is therefore essential. For transportation applications,an energy carrier offering a high energy density is needed. Ammonia...... is one possible energy carrier offering high gravimetric and volumetric capacities. A major drawback regarding ammonia is however its toxicity requiring careful handling and storage.Instead of handling the ammonia directly, it is possible to store it safely and completely reversibly in many different...

  10. Continuous ammonia monitor using a Stark microwave cavity resonator.

    Science.gov (United States)

    Uehara, H; Ijuuin, Y; Morino, Y; Kamidate, T; Nakamura, A; Imai, H

    1980-03-01

    An ammonia monitor has been made by using a rectangular Stark microwave cavity tightly coupled through an iris to a Gunn oscillator. The Stark electrode installed inside the cavity is provided with a 100 kHz sinusoidal modulation voltage and a dc sweep voltage. The oscillation of the Gunn diode is tuned with the coupled Stark cavity to a frequency near a J,K=3,3 transition (23870.1 MHz) of ammonia. By fixing the Stark dc bias to a voltage which gives a peak intensity of the derivative output of the electric-resonance signal, ammonia is continuously monitored. An extremely good long-term stability is obtained. The noise level corresponds to 0.08 ppm of ammonia.

  11. Simultaneous Graphite Exfoliation and N Doping in Supercritical Ammonia.

    Science.gov (United States)

    Sasikala, Suchithra Padmajan; Huang, Kai; Giroire, Baptiste; Prabhakaran, Prem; Henry, Lucile; Penicaud, Alain; Poulin, Philippe; Aymonier, Cyril

    2016-11-16

    We report the exfoliation of graphite and simultaneous N doping of graphene by two methods: supercritical ammonia treatment and liquid-phase exfoliation with NH4OH. While the supercritical ammonia allowed N doping at a level of 6.4 atom % in 2 h, the liquid-phase exfoliation with NH4OH allowed N doping at a level of 2.7 atom % in 6 h. The N doped graphene obtained via the supercritical ammonia route had few layers (supercritical ammonia as an exfoliation agent and N doping precursor for graphene. Notably, the N doped graphene showed electrocatalytic activity toward oxygen reduction reaction with high durability and good methanol tolerance compared to those of commercial Pt/C catalyst.

  12. The concentration of ammonia regulates nitrogen metabolism in Saccharomyces cerevisiae.

    Science.gov (United States)

    ter Schure, E G; Silljé, H H; Verkleij, A J; Boonstra, J; Verrips, C T

    1995-11-01

    Saccharomyces cerevisiae was grown in a continuous culture at a single dilution rate with input ammonia concentrations whose effects ranged from nitrogen limitation to nitrogen excess and glucose limitation. The rate of ammonia assimilation (in millimoles per gram of cells per hour) was approximately constant. Increased extracellular ammonia concentrations are correlated with increased intracellular glutamate and glutamine concentrations, increases in levels of NAD-dependent glutamate dehydrogenase activity and its mRNA (gene GDH2), and decreases in levels of NADPH-dependent glutamate dehydrogenase activity and its mRNA (gene GDH1), as well as decreases in the levels of mRNA for the amino acid permease-encoding genes GAP1 and PUT4. The governing factor of nitrogen metabolism might be the concentration of ammonia rather than its flux.

  13. [Inhibition of aromatics on ammonia-oxidizing activity of sediment].

    Science.gov (United States)

    Dong, Chun-hong; Hu, Hong-ying; Wei, Dong-bin; Huang, Xia; Qian, Yi

    2004-03-01

    The inhibition of 24 aromatics on ammonia-oxidizing activity of nitrifying bacteria in sediment was measured. The effects of the kind, number and position of substituted groups on ammonia-oxidizing activity of nitrifying bacteria were discussed. The inhibition of mono-substituted benzenes on ammonia-oxidizing activity of nitrifying bacteria were in order of -OH > -NO2 > -NH2 > -Cl > -CH3 > -H. The position of substituted groups of di-substituted benzenes also affected the inhibition, and the inhibitions of dimethylbenzenes(xylene) were in order of meta-> ortho-> para-. The increase in number of substituted group on benzene-ring enhanced the inhibition of aromatics studied in this study on nitrifying bacteria. There was a linear relationship between inhibition (IC50, mumol.L-1) of aromatics on ammonia-oxidizing activity and total electronegativity (sigma E) of aromatics: lgIC50 = 14.72 - 0.91 sigma E.

  14. Risk analysis and emergency management of ammonia installations

    NARCIS (Netherlands)

    Ham, J.M.; Gansevoort, J.

    1992-01-01

    The use of Quantitative Risk Assessment has been increasing for evaluating the risk of handling hazardous materials and land-use planning. This article reports on several studies carried out on the risk of handling, storage and transport of ammonia.

  15. Role of ammonia in the pathogenesis of brain edema.

    Directory of Open Access Journals (Sweden)

    Fujiwara,Masachika

    1986-12-01

    Full Text Available The role of hyperammonemia in the pathogenesis of cerebral edema was investigated using mongrel dogs to develop a treatment for cerebral edema in acute hepatic failure. Intravenous infusion of ammonium acetate alone into dogs did not induce brain edema, although blood ammonia reached unphysiologically high levels. However, ammonium acetate infusion during mannitol-induced reversible (osmotic opening of the blood-brain barrier (BBB effectively induced cytotoxic brain edema. Pretreatment with a branched-chain amino acid (BCAA; valine, leucine and isoleucine solution prevented an increase in intracranial pressure (ICP and brain water content, and caused a decrease in brain ammonia content and an increase in brain BCAA and glutamic acid. The results suggest that ammonia plays an important role in the pathogenesis of cerebral edema during acute hepatic failure and that BCAAs accelerate ammonia detoxification in the brain.

  16. Study on austenitic nitrocarburizing without compound layer

    Energy Technology Data Exchange (ETDEWEB)

    Yang, X. [Univ. of Petroleum, Dongying, Shandong (China); Kong, C.; Qiao, Y. [Shandong Polytechnic Univ., Jinan, Shandong (China)

    1995-12-31

    This paper presents an advanced austenitic nitrocarburizing process. Medium-carbon steel was used in austenitic nitrocarburizing with methanol/ammonia atmospheres. A particular hardened case without compound layer was obtained at 680 C processing temperature and a moderate nitrogen potential level and for steel 45 nitrocarburized, there is a fine-grain region beneath the austenite case. The forming and developing mechanism of the fine-grain region was analyzed and the microhardness profiles of the layer before and after ageing were determined. Having the advantages of shorter processing time and a superior hardened case, this treatment is expected to supersede the conventional ferritic nitrocarburizing process in many wear resistance applications.

  17. Exhaust purification with on-board ammonia production

    Science.gov (United States)

    Robel, Wade J.; Driscoll, James Joshua; Coleman, Gerald N.

    2008-05-13

    A system of ammonia production for a selective catalytic reduction system is provided. The system includes producing an exhaust gas stream within a cylinder group, wherein the first exhaust gas stream includes NOx. The exhaust gas stream may be supplied to an exhaust passage and cooled to a predetermined temperature range, and at least a portion of the NOx within the exhaust gas stream may be converted into ammonia.

  18. Ammonia corrodes solar modules; Salmiakgeist greift Module an

    Energy Technology Data Exchange (ETDEWEB)

    Petzold, Katrin

    2011-07-01

    Ammonia is an aggressive gas produced in animal shelters, which may cause corrosion of solar modules. Various institutions, e.g. DLG and TUeV Rheinland, therefore offer an ammonia test for solar modules. The TUeV Rheinland recently commissioned a walk-in test chamber and now issues an official seal of approval, while the DLG doubts the practical value of the test.

  19. Growth of organic microspherules in sugar-ammonia reactions.

    Science.gov (United States)

    Weber, Arthur L

    2005-12-01

    Reaction of small sugars of less than four carbons with ammonia in water yielded organic microspherules generally less than ten microns in size. The time course of microspherule growth was examined for the D-erythrose-ammonia reaction that yielded microspherules attached to the glass walls of containers. Measurements were made of the elemental composition and infrared spectrum of the microspherule material. These viscose semi-solid microspherules are viewed as possible containers for prebiotic catalytic processes relevant to the origin of life.

  20. Isotopic Discrimination of Some Solutes in Liquid Ammonia

    Science.gov (United States)

    Taube, H.; Viste, A.

    1966-01-01

    The nitrogen isotopic discrimination of some salts and metals, studies in liquid ammonia solution at -50�C, decreases in magnitude in the order Pb{sup ++}, Ca{sup ++}, Li{sup +}, AG{sup +}, Na{sup +}, Li, K{sup +}, Na, K. The isotopic discrimination appears to provide qualitative information about the strength of the cation-solvent interaction in liquid ammonia.

  1. Ammonia nitrogen desorption from sanitary landfill leachate in filling towers

    OpenAIRE

    Leite,Valderi D.; Barros,Aldre J. M.; Lopes,Wilton S.; Sousa,José T. de

    2014-01-01

    Sanitary landfill leachates present high concentrations of carbonaceous and nitrogenous materials. The crucial point is that carbonaceous materials are of difficult biodegradation, what compromises the performance of biological treatment processes, while nitrogenous materials, such as ammonia nitrogen, probably preclude the use of biological treatments. Therefore, the aim of this work was to study the desorption process of ammonia nitrogen from sanitary landfill leachate in filling towers. De...

  2. On the photoionization and fragmentation of ammonia clusters using TPEPICO

    Energy Technology Data Exchange (ETDEWEB)

    Kamke, W.; Herrmann, R.; Wang, Z.; Hertel, I.V.

    1988-12-01

    Measurements of the appearance potentials of ammonia cluster ions (NH/sub 3/)/sub n//sup +/ and (NH/sub 3/)/sub n-2/NH/sub 4//sup +/ using the threshold photoelectron photoion coincidence (TPEPICO) time-of-flight method are performed. The results agree well with other available data, however, solvation energies derived from these and from thermochemical data show significant discrepancies. The energetics for ammonia clusters are elucidated from various points of view.

  3. Ammonia at Blodgett Forest, Sierra Nevada, USA

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Marc L.; Littlejohn, David

    2007-11-06

    Ammonia is a reactive trace gas that is emitted in large quantities by animal agriculture and other sources in California, which subsequently forms aerosol particulate matter, potentially affecting visibility, climate, and human health. We performed initial measurements of NH{sub 3} at the Blodgett Forest Research Station (BFRS) during a two week study in June, 2006. The site is used for ongoing air quality research and is a relatively low-background site in the foothills of the Sierra Nevada. Measured NH{sub 3} mixing ratios were quite low (< 1 to {approx} 2 ppb), contrasting with typical conditions in many parts of the Central Valley. Eddy covariance measurements showed NH{sub 3} fluxes that scaled with measured NH{sub 3} mixing ratio and calculated aerodynamic deposition velocity, suggesting dry deposition is a significant loss mechanism for atmospheric NH{sub 3} at BFRS. A simple model of NH{sub 3} transport to the site supports the hypothesis that NH{sub 3} is transported from the Valley to BFRS, but deposits on vegetation during the summer. Further work is necessary to determine whether the results obtained in this study can be generalized to other seasons.

  4. Measurements of Ammonia at Blodgett Forest

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Marc L.; Littlejohn, David

    2007-04-01

    Ammonia is a reactive trace gas that is emitted in large quantities by animal agriculture and other sources in California, which subsequently forms aerosol particulate matter, potentially affecting visibility, climate, and human health. We performed initial measurements of NH{sub 3} at the Blodgett Forest Research Station (BFRS) during a 3 week study in June, 2006. The site is used for ongoing air quality research and is a relatively low-background site in the foothills of the Sierra Nevada. Measured NH{sub 3} mixing ratios were quite low (< 1 to {approx}2 ppb), contrasting with typical conditions in many parts of the Central Valley. Eddy covariance measurements showed NH{sub 3} fluxes that scaled with measured NH{sub 3} mixing ratio and calculated aerodynamic deposition velocity, suggesting dry deposition is a significant loss mechanism for atmospheric NH{sub 3} at BFRS. A simple model of NH{sub 3} transport to the site supports the hypothesis that NH{sub 3} is transported from the Valley to BFRS, but deposits on vegetation during the summer. Further work is necessary to determine whether the results obtained in this study can be generalized to other seasons.

  5. Triply deuterated ammonia in NGC 1333

    CERN Document Server

    Van der Tak, F F S; Müller, H S P; Lis, D C; Phillips, T G; Gerin, M; Roueff, E

    2002-01-01

    The Caltech Submillimeter Observatory has detected triply deuterated ammonia, ND3, through its 10a-00s transition near 310 GHz. Emission is found in the NGC 1333 region, both towards IRAS 4A and a position to the South-East where DCO+ peaks. In both cases, the hyperfine ratio indicates that the emission is optically thin. Column densities of ND3 are 3--6 x 10^11 cm^-2 for T_ex=10 K and twice as high for T_ex=5 K. Using a Monte Carlo radiative transfer code and a model of the structure of the IRAS source with temperature and density gradients, the estimated ND3 abundance is 3.2 x 10^-12 if ND3/H2 is constant throughout the envelope. In the more likely case that ND3/H2D+ is constant, ND3/H2 peaks in the cold outer parts of the source at a value of 1.0 x 10^-11. To reproduce the observed NH3/ND3 abundance ratio of ~1000, grain surface chemistry requires an atomic D/H ratio of ~0.15 in the gas phase, >10 times higher than in recent chemical models. More likely, the deuteration of NH3 occurs by ion-molecule reacti...

  6. Nitridation of chromium powder in ammonia atmosphere

    Institute of Scientific and Technical Information of China (English)

    Ling Li; Qiang Zhen; Rong Li

    2015-01-01

    CrN powder was synthesized by nitriding Cr metal in ammonia gas flow, and its chemical reaction mechanism and nitridation process were studied. Through thermodynamic calculations, the Cr−N−O predominance diagrams were constructed for different tempera-tures. Chromium nitride formed at 700−1200°C under relatively higher nitrogen and lower oxygen partial pressures. Phases in the products were then investigated using X-ray diffraction (XRD), and the Cr2N content varied with reaction temperature and holding time. The results indicate that the Cr metal powder nitridation process can be explained by a diffusion model. Further, Cr2N formed as an intermediate product because of an incomplete reaction, which was observed by high-resolution transmission electron microscopy (HRTEM). After nitriding at 1000°C for 20 h, CrN powder with an average grain size of 63 nm was obtained, and the obtained sample was analyzed by using a scanning electron microscope (SEM).

  7. The role of glutamate dehydrogenase in mammalian ammonia metabolism.

    Science.gov (United States)

    Spanaki, Cleanthe; Plaitakis, Andreas

    2012-01-01

    Glutamate dehydrogenase (GDH) catalyzes the reversible inter-conversion of glutamate to α-ketoglutarate and ammonia. High levels of GDH activity is found in mammalian liver, kidney, brain, and pancreas. In the liver, GDH reaction appears to be close-to-equilibrium, providing the appropriate ratio of ammonia and amino acids for urea synthesis in periportal hepatocytes. In addition, GDH produces glutamate for glutamine synthesis in a small rim of pericentral hepatocytes. Hence, hepatic GDH can be either a source for ammonia or an ammonia scavenger. In the kidney, GDH function produces ammonia from glutamate to control acidosis. In the human, the presence of two differentially regulated isoforms (hGDH1 and hGDH2) suggests a complex role for GDH in ammonia homeostasis. Whereas hGDH1 is sensitive to GTP inhibition, hGDH2 has dissociated its function from GTP control. Furthermore, hGDH2 shows a lower optimal pH than hGDH1. The hGDH2 enzyme is selectively expressed in human astrocytes and Sertoli cells, probably facilitating metabolic recycling processes essential for their supportive role. Here, we report that hGDH2 is also expressed in the epithelial cells lining the convoluted tubules of the renal cortex. As hGDH2 functions more efficiently under acidotic conditions without the operation of the GTP energy switch, its presence in the kidney may increase the efficacy of the organ to maintain acid base equilibrium.

  8. Optimality in the zonation of ammonia detoxification in rodent liver.

    Science.gov (United States)

    Bartl, Martin; Pfaff, Michael; Ghallab, Ahmed; Driesch, Dominik; Henkel, Sebastian G; Hengstler, Jan G; Schuster, Stefan; Kaleta, Christoph; Gebhardt, Rolf; Zellmer, Sebastian; Li, Pu

    2015-11-01

    The rodent liver eliminates toxic ammonia. In mammals, three enzymes (or enzyme systems) are involved in this process: glutaminase, glutamine synthetase and the urea cycle enzymes, represented by carbamoyl phosphate synthetase. The distribution of these enzymes for optimal ammonia detoxification was determined by numerical optimization. This in silico approach predicted that the enzymes have to be zonated in order to achieve maximal removal of toxic ammonia and minimal changes in glutamine concentration. Using 13 compartments, representing hepatocytes, the following predictions were generated: glutamine synthetase is active only within a narrow pericentral zone. Glutaminase and carbamoyl phosphate synthetase are located in the periportal zone in a non-homogeneous distribution. This correlates well with the paradoxical observation that in a first step glutamine-bound ammonia is released (by glutaminase) although one of the functions of the liver is detoxification by ammonia fixation. The in silico approach correctly predicted the in vivo enzyme distributions also for non-physiological conditions (e.g. starvation) and during regeneration after tetrachloromethane (CCl4) intoxication. Metabolite concentrations of glutamine, ammonia and urea in each compartment, representing individual hepatocytes, were predicted. Finally, a sensitivity analysis showed a striking robustness of the results. These bioinformatics predictions were validated experimentally by immunohistochemistry and are supported by the literature. In summary, optimization approaches like the one applied can provide valuable explanations and high-quality predictions for in vivo enzyme and metabolite distributions in tissues and can reveal unknown metabolic functions.

  9. Uptake of ammonia by Saccharomyces cerevisiae carrying the plasmid pCYG4 related with ammonia assimilation.

    Science.gov (United States)

    Lima Filho, J L; Ledingham, W M

    1992-08-01

    Batch culture experiments involving ammonia uptake in Saccharomyces cerevisiae BC55 pCYG4 have been carried out. This strain carries the plasmid pCYG4 that directs substantial overproduction of NADP-GDH, conferring an 11-fold increase in activity. The wild type cells had a specific growth rate greater than BC55 pCYG4. The ammonia uptake was practically the same until 15 h of growth. However, the amount of ammonia hydroxide added during growth (60 h) was two and half times greater in the BC55 pCYG4 than wild type cells. The results suggest that the presence of the plasmid pCYG4 can increase the amount of ammonia taken by the cells, but not the amount of biomass.

  10. Submersible microbial desalination cell for simultaneous ammonia recovery and electricity production from anaerobic reactors containing high levels of ammonia

    DEFF Research Database (Denmark)

    Zhang, Yifeng; Angelidaki, Irini

    2015-01-01

    High ammonia concentration in anaerobic reactors can seriously inhibit the anaerobic digestion process. In this study, a submersible microbial desalination cell (SMDC) was developed as an innovative method to lower the ammonia level in a continuous stirred tank reactor (CSTR) by in situ ammonia...... recovery and electricity production. In batch experiment, the ammonia concentration in the CSTR decreased from 6 to 0.7g-N/L during 30days, resulting in an average recovery rate of 80g-N/m2/d. Meanwhile, a maximum power density of 0.71±0.5W/m2 was generated at 2.85A/m2. Both current driven NH4+ migration...

  11. Tolerance response to in situ ammonia stress in a pilot-scale anaerobic digestion reactor for alleviating ammonia inhibition.

    Science.gov (United States)

    Gao, Shumei; Zhao, Mingxing; Chen, Yang; Yu, Meijuan; Ruan, Wenquan

    2015-12-01

    The anaerobic digestion (AD) of protein-rich substrates is generally inhibited by ammonia. In this study, ammonia-tolerant acclimation was exposed to a stepwise in situ ammonia stress during the continuous AD of solid residual kitchen waste by using a continuous stirred tank reactor with a 50 L active volume. The reactor worked well during the acclimation process, with an average daily biogas production of 58 L/d, an effluent soluble chemical oxygen demand of 7238 mg/L, a volatile fatty acid (VFA) content of 578 mg/L, and a VFA/alkalinity ratio of less than 0.4. Moreover, ammonia stress enhanced the activity of Coenzyme F420. The results of high-throughput 16S rDNA sequencing showed that ammonia stress increased the relative abundance of Firmicutes bacteria and hydrogenotrophic methanogens but decreased the abundance of acetotrophic methanogens. This microbial community shift was proposed to be an in situ response strategy for ammonia stress adaptation.

  12. UF6 and UF4 in liquid ammonia: [UF7(NH3)]3- and [UF4(NH3)4].

    Science.gov (United States)

    Kraus, Florian; Baer, Sebastian A

    2009-08-17

    From the reaction of uranium hexafluoride UF6 with dry liquid ammonia, the [UF7(NH3)]3- anion and the [UF4(NH3)4] molecule were isolated and identified for the first time. They are found in signal-green crystals of trisammonium monoammine heptafluorouranate(IV) ammonia (1:1; [NH4]3[UF7(NH3)].NH3) and emerald-green crystals of tetraammine tetrafluorouranium(IV) ammonia (1:1; [UF4(NH3)4].NH3). [NH4]3[UF7(NH3)].NH3 features discrete [UF7(NH3)]3- anions with a coordination geometry similar to a bicapped trigonal prism, hitherto unknown for U(IV) compounds. The emerald-green [UF4(NH3)4].NH3 contains discrete tetraammine tetrafluorouranium(IV) [UF4(NH3)4] molecules. [UF4(NH3)4].NH3 is not stable at room temperature and forms pastel-green [UF4(NH3)4] as a powder that is surprisingly stable up to 147 degrees C. The compounds are the first structurally characterized ammonia complexes of uranium fluorides.

  13. A longitudinal study of ammonia, acetone and propanol in the exhaled breath of 30 subjects using selected ion flow tube mass spectrometry, SIFT-MS.

    Science.gov (United States)

    Turner, Claire; Spanel, Patrik; Smith, David

    2006-04-01

    Selected ion flow tube mass spectrometry, SIFT-MS, has been used to monitor the volatile compounds in the exhaled breath of 30 volunteers (19 males, 11 females) over a 6 month period. Volunteers provided breath samples each week between 8:45 am and 1 pm (before lunch), and the concentrations of several trace compounds were obtained. In this paper the focus is on ammonia, acetone and propanol. It was found that the concentration distributions of these compounds in breath were close to log-normal. The median ammonia level estimated as a geometric mean for all samples was 833 parts per billion (ppb) with a multiplicative standard deviation of 1.62, the values ranging from 248 to 2935 ppb. Breath ammonia clearly increased with increasing age in this volunteer cohort. The geometric mean acetone level for all samples was 477 parts per billion (ppb) with a multiplicative standard deviation of 1.58, the values ranging from 148 to 2744 ppb. The median propanol level for all samples was 18 ppb, the values ranging from 0 to 135 ppb. A weak but significant correlation between breath propanol and acetone levels is apparent in the data. The findings indicate the potential value of SIFT-MS as a non-invasive breath analysis technique for investigating volatile compounds in human health and in the diseased state.

  14. Habitat-associated phylogenetic community patterns of microbial ammonia oxidizers.

    Directory of Open Access Journals (Sweden)

    Antoni Fernàndez-Guerra

    Full Text Available Microorganisms mediating ammonia oxidation play a fundamental role in the connection between biological nitrogen fixation and anaerobic nitrogen losses. Bacteria and Archaea ammonia oxidizers (AOB and AOA, respectively have colonized similar habitats worldwide. Ammonia oxidation is the rate-limiting step in nitrification, and the ammonia monooxygenase (Amo is the key enzyme involved. The molecular ecology of this process has been extensively explored by surveying the gene of the subunit A of the Amo (amoA gene. In the present study, we explored the phylogenetic community ecology of AOB and AOA, analyzing 5776 amoA gene sequences from >300 isolation sources, and clustering habitats by environmental ontologies. As a whole, phylogenetic richness was larger in AOA than in AOB, and sediments contained the highest phylogenetic richness whereas marine plankton the lowest. We also observed that freshwater ammonia oxidizers were phylogenetically richer than their marine counterparts. AOA communities were more dissimilar to each other than those of AOB, and consistent monophyletic lineages were observed for sediments, soils, and marine plankton in AOA but not in AOB. The diversification patterns showed a more constant cladogenesis through time for AOB whereas AOA apparently experienced two fast diversification events separated by a long steady-state episode. The diversification rate (γ statistic for most of the habitats indicated γ(AOA > γ(AOB. Soil and sediment experienced earlier bursts of diversification whereas habitats usually eutrophic and rich in ammonium such as wastewater and sludge showed accelerated diversification rates towards the present. Overall, this work shows for the first time a global picture of the phylogenetic community structure of both AOB and AOA assemblages following the strictest analytical standards, and provides an ecological view on the differential evolutionary paths experienced by widespread ammonia

  15. Magnesium compounds

    Science.gov (United States)

    Kramer, D.A.

    2012-01-01

    Seawater and natural brines accounted for about 57 percent of magnesium compounds produced in the United States in 2011. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties LLC from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Magnesia LLC in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Magnesia. Intrepid Potash Wendover LLC and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma Inc. in Delaware and Premier Magnesia in Florida, and by Martin Marietta from its brine operation in Michigan.

  16. 不同煤焦油沥青与吡啶硼烷反应性能的比较%STUDY OF REACTIVITY BETWEEN DIFFERENT COAL TAR PITCHES AND PYRIDINE-BORANE

    Institute of Scientific and Technical Information of China (English)

    张丽芳; 宋进仁; 要立中; 刘朗

    2001-01-01

    以三种不同的煤焦油沥青为原料,分别与吡啶硼烷反应制备了硼取代中间相沥青。比较了它们的软化点、残炭值、四氢呋喃不溶物(THFI)以及中间相的偏光显微结构。发现煤焦油沥青不同所得结果有显著差别:较高软化点的沥青与吡啶硼烷的反应活性较强,而相同软化点的净化煤焦油沥青与吡啶硼烷具有更强的反应性,所得中间相沥青的软化点、残炭值及四氢呋喃不溶物的含量较高,其偏光显微结构也证实了这一点。%Boron-substituted mesophase pitches were synthesized by co-pyrolysis of different coal tar pitches with pyridine-borane complex.The softing points, coke yields, solubility in tetrahydrofurane (THF) and polarized micrographs were compared. It is found that the results are different. The coal tar pitch with high soffening point after purification had higher reactivity with pyridine-borane, which was proved by the soffening point, coke yield solubitily in THF and polarized microstructure of obtained pitch.

  17. The Search for Ammonia in Martian Soils with Curiosity's SAM Instrument

    Science.gov (United States)

    Wray, James J.; Archer, P. D.; Brinckerhoff, W. B.; Eigenbrode, J. L.; Franz, H. B.; Freissinet, C.; Glavin, D. P.; Mahaffy, P. R.; McKay, C. P.; Navarro-Gonzalez, R.; Steele, A.; Webster, C. R.

    2013-01-01

    Nitrogen is the second or third most abundant constituent of the Martian atmosphere [1,2]. It is a bioessential element, a component of all amino acids and nucleic acids that make up proteins, DNA and RNA, so assessing its availability is a key part of Curiosity's mission to characterize Martian habitability. In oxidizing desert environments it is found in nitrate salts that co-occur with perchlorates [e.g., 3], inferred to be widespread in Mars soils [4-6]. A Mars nitrogen cycle has been proposed [7], yet prior missions have not constrained the state of surface N. Here we explore Curiosity's ability to detect N compounds using data from the rover's first solid sample. Companion abstracts describe evidence for nitrates [8] and for nitriles (C(triple bond)N) [9]; we focus here on nonnitrile, reduced-N compounds as inferred from bonded N-H. The simplest such compound is ammonia (NH3), found in many carbonaceous chondrite meteorites in NH4(+) salts and organic compounds [e.g., 10].

  18. Effect of zeolite on toxicity of ammonia in freshwater sediments: Implications for toxicity identification evaluation procedures

    Energy Technology Data Exchange (ETDEWEB)

    Besser, J.M.; Ingersoll, C.G. [Geological Survey, Columbia, MO (United States); Leonard, E.N.; Mount, D.R. [Environmental Protection Agency, Duluth, MN (United States). Mid-Continent Ecology Div.

    1998-11-01

    Techniques for reducing ammonia toxicity in freshwater sediments were investigated as part of a project to develop toxicity identification and evaluation (TIE) procedures for whole sediments. Although ammonia is a natural constituent of freshwater sediments, pollution can lead to ammonia concentrations that are toxic to benthic invertebrates, and ammonia can also contribute to the toxicity of sediments that contain more persistent contaminants. The authors investigated the use of amendments of a natural zeolite mineral, clinoptilolite, to reduce concentrations of ammonia in sediment pore water. Zeolites have been widely used for removal of ammonia in water treatment and in aqueous TIE procedures. The addition of granulated zeolite to ammonia-spiked sediments reduced pore-water ammonia concentrations and reduced ammonia toxicity to invertebrates. Amendments of 20% zeolite (v/v) reduced ammonia concentrations in pore water by {ge}70% in spiked sediments with ammonia concentrations typical of contaminated freshwater sediments. Zeolite amendments reduced toxicity of ammonia-spiked sediments to three taxa of benthic invertebrates (Hyalella azteca, Lumbriculus variegatus, and Chironomus tentans), despite their widely differing sensitivity to ammonia toxicity. In contrast, zeolite amendments did not reduce acute toxicity of sediments containing high concentrations of cadmium or copper or reduce concentrations of these metals in pore waters. These studies suggest that zeolite amendments, used in conjunction with toxicity tests with sensitive taxa such as H. azteca, may be an effective technique for selective reduction of ammonia toxicity in freshwater sediments.

  19. A Parametric Study for Regenerative Ammonia-Based Scrubbing for the Capture of CO2

    Energy Technology Data Exchange (ETDEWEB)

    Resnik, K.P.; Garber, W.; Hreda, D.C.; Yeh, J.T.; Pennline, H.W.

    2006-09-01

    A continuous gas and liquid flow, regenerative scrubbing process for CO2 capture is currently being demonstrated at the bench-scale level. An aqueous ammonia-based solution captures CO2 from simulated flue gas in an absorber and releases a nearly pure stream of CO2 in the regenerator. After the regeneration, the solution of ammonium compounds is recycled to the absorber. The design of the continuous flow unit was based on earlier exploratory results from a semi-batch reactor, where a CO2 and N2 gas mixture flowed through a well-mixed batch of ammonia-based solution. Recently, a series of tests have been conducted on the continuous unit to observe the effect of various parameters on CO2 removal efficiency and regenerator effectiveness within the flow system. The parameters that were studied include absorber temperature, regenerator temperature, initial NH3 concentration, simulated flue gas flow rate, liquid solvent inventory in the flow system, and height of the packed-bed absorber. Results from this current testing campaign conducted in the continuous scrubbing unit as well as test results from a 5-cycle semi-batch reactor will be discussed.

  20. Chromophores from photolyzed ammonia reacting with acetylene: Application to Jupiter's Great Red Spot

    Science.gov (United States)

    Carlson, R. W.; Baines, K. H.; Anderson, M. S.; Filacchione, G.; Simon, A. A.

    2016-08-01

    The high altitude of Jupiter's Great Red Spot (GRS) may enhance the upward flux of gaseous ammonia (NH3) into the high troposphere, where NH3 molecules can be photodissociated and initiate a chain of chemical reactions with downwelling acetylene molecules (C2H2). These reactions, experimentally studied earlier by (Ferris and Ishikawa [1987] Nature 326, 777-778) and (Ferris and Ishikawa [1988] J. Amer. Chem. Soc. 110, 4306-4312), produce chromophores that absorb in the visible and ultraviolet regions. In this work we photolyzed mixtures of NH3 and C2H2 using ultraviolet radiation with a wavelength of 214 nm and measured the spectral transmission of the deposited films in the visible region (400-740 nm). From these transmission data we estimated the imaginary indices of refraction. Assuming that ammonia grains at the top of the GRS clouds are coated with this material, we performed layered sphere and radiative transfer calculations to predict GRS reflection spectra. Comparison of those results with observed and previously unreported Cassini visible spectra and with true-color images of the GRS show that the unknown GRS chromophore is spectrally consistent with the coupled NH3-C2H2 photochemical products produced in our laboratory experiments. Using high-resolution mass spectrometry and infrared spectroscopy we infer that the chromophore-containing residue is composed of aliphatic azine, azo, and diazo compounds.

  1. Ammonia and ethylene biomarkers in the respiration of the people with schizophrenia using photoacoustic spectroscopy

    Science.gov (United States)

    Popa, Cristina; Petrus, Mioara; Bratu, Ana Maria

    2015-05-01

    Oxidative stress has become an exciting area of schizophrenia (SCZ) research, and provides ample opportunities and hope for a better understanding of its pathophysiology, which may lead to new treatment strategies. The first objective of the present study was to analyze the oxidative stress markers in breath samples of patients with SCZ before and after the treatment with Levomepromazine. The second objective was to analyze the deficiency of amino acids marker in breath samples of patients with SCZ before and after the treatment. Exhaled breath was collected from 15 SCZ patients and 19 healthy controls; subsequently, CO2 laser photoacoustic spectroscopy was used to assess the exhaled breath compounds of the study subjects. One of the main breath biomarkers of the oxidative stress is ethylene, while one of the main breath biomarkers of the amino acids deficiency is ammonia. The breath biomarkers in the exhalation of SCZ patients exhibited significant differences from the breath biomarkers in the exhalation of healthy controls. Analysis of breath ethylene and breath ammonia provides a related model of SCZ exhalation that could represent an effective and convenient screening method for this intellectual disability.

  2. Comparison of VOC and ammonia emissions from individual PVC materials, adhesives and from complete structures.

    Science.gov (United States)

    Järnström, H; Saarela, K; Kalliokoski, P; Pasanen, A-L

    2008-04-01

    Emission rates of volatile organic compounds (VOCs) and ammonia measured from six PVC materials and four adhesives in the laboratory were compared to the emission rates measured on site from complete structures. Significantly higher specific emission rates (SERs) were generally measured from the complete structures than from individual materials. There were large differences between different PVC materials in their permeability for VOCs originating from the underlying structure. Glycol ethers and esters from adhesives used in the installation contributed to the emissions from the PVC covered structure. Emissions of 2-ethylhexanol and TXIB (2,2,4-trimethyl-1,3-pentanediol diisobutyrate) were common. High ammonia SERs were measured from single adhesives but their contribution to the emissions from the complete structure did not appear as obvious as for VOCs. The results indicate that three factors affected the VOC emissions from the PVC flooring on a structure: 1) the permeability of the PVC product for VOCs, 2) the VOC emission from the adhesive used, and 3) the VOC emission from the backside of the PVC product.

  3. Emission, transmission, deposition and environmental effects of ammonia from agricultural sources

    Energy Technology Data Exchange (ETDEWEB)

    Erisman, J.W. [ECN Clean Fossil Fuels, Petten (Netherlands); Dammgen, U. [Federal Agricultural Research Centre, Institute of Agroecology, Braunschweig (Germany)

    2005-05-01

    Air pollution in Europe has been regarded as a severe problem for several decades, the adverse effects being: the influence on the physical properties of the atmosphere itself, in particular its energy balance (global warming), and visibility; the influence on atmospheric chemistry (formation and destruction of both ground level and stratospheric ozone); the input of chemicals into terrestrial and aquatic ecosystems causing acidification and eutrophication leading to forest decline as well as changes in ecosystem structure and function; the effects on human health and welfare (the respiratory system). Since the sulfur dioxide problem seems to have been solved to a large extent in most countries in Western Europe, atmospheric nitrogen compounds are considered a major source of acidification. As most natural and near-natural ecosystems have developed with nitrogen as a limiting factor, increased inputs of reactive atmospheric nitrogen cause changes in their structure, function and nutrient dynamics. These effects are attributed to surplus nutrition (eutrophication) of the respective systems as the result of increased nitrogen inputs. At first it seemed logical to connect them with sources similar to those for sulfur (power plants, combustion engines, domestic heating); however, it soon became clear that reduced nitrogen (ammonia and ammonium in particulates) also plays a major role. This review is to collate the present state of knowledge with regard to ammonia emissions, its atmospheric transport and chemistry as well as its deposition and the resulting effects. It restricts itself to a description of the situation in Europe.

  4. Chromophores from photolyzed ammonia reacting with acetylene: Application to Jupiters Great Red Spot

    Science.gov (United States)

    Carlson, Robert W.; Baines, Kevin H.; Anderson, M. S.; Filacchione, G.; Simon, A. A.

    2016-01-01

    The high altitude of Jupiter's Great Red Spot (GRS) may enhance the upward flux of gaseous ammonia (NH3 ) into the high troposphere, where NH3 molecules can be photodissociated and initiate a chain of chemical reactions with downwelling acetylene molecules (C2H2 ). These reactions, experimentally studied earlier by (Ferris and Ishikawa [1987] Nature 326, 777-778) and (Ferris and Ishikawa [1988] J. Amer. Chem. Soc. 110, 4306-4312), produce chromophores that absorb in the visible and ultraviolet regions. In this work we photolyzed mixtures of NH3 and C2H2 using ultraviolet radiation with a wavelength of 214 nm and measured the spectral transmission of the deposited films in the visible region (400-740 nm). From these transmission data we estimated the imaginary indices of refraction. Assuming that ammonia grains at the top of the GRS clouds are coated with this material, we performed layered sphere and radiative transfer calculations to predict GRS reflection spectra. Comparison of those results with observed and previously unreported Cassini visible spectra and with true-color images of the GRS show that the unknown GRS chromophore is spectrally consistent with the coupled NH3-C2H2 photochemical products produced in our laboratory experiments. Using high-resolution mass spectrometry and infrared spectroscopy we infer that the chromophore-containing residue is composed of aliphatic azine, azo, and diazo compounds.

  5. CHEMICAL PROCESSING OF PURE AMMONIA AND AMMONIA-WATER ICES INDUCED BY HEAVY IONS

    Energy Technology Data Exchange (ETDEWEB)

    Bordalo, V.; Da Silveira, E. F. [Departamento de Fisica/Laboratorio do Acelerador Van de Graaff, Pontificia Universidade Catolica do Rio de Janeiro, Rua Marques de S. Vicente 225, 22451-900 Rio de Janeiro, RJ (Brazil); Lv, X. Y.; Domaracka, A.; Rothard, H.; Boduch, P. [Centre de Recherche sur les Ions, les Materiaux et la Photonique (CEA/CNRS/ENSICAEN/Universite de Caen-Basse Normandie), CIMAP-CIRIL-GANIL, Boulevard Henri Becquerel, BP 5133, F-14070 Caen Cedex 05 (France); Seperuelo Duarte, E., E-mail: vbordalo@fis.puc-rio.br [Grupo de Fisica e Astronomia, Instituto Federal do Rio de Janeiro, Rua Lucio Tavares 1045, 26530-060 Nilopolis, RJ (Brazil)

    2013-09-10

    Cosmic rays are possibly the main agents to prevent the freeze-out of molecules onto grain surfaces in cold dense clouds. Ammonia (NH{sub 3}) is one of the most abundant molecules present in dust ice mantles, with a concentration of up to 15% relative to water (H{sub 2}O). FTIR spectroscopy is used to monitor pure NH{sub 3} and NH{sub 3}-H{sub 2}O ice samples as they are irradiated with Ni and Zn ion beams (500-600 MeV) at GANIL/France. New species, such as hydrazine (N{sub 2}H{sub 4}), diazene (N{sub 2}H{sub 2} isomers), molecular hydrogen (H{sub 2}), and nitrogen (N{sub 2}) were identified after irradiation of pure NH{sub 3} ices. Nitrous oxide (N{sub 2}O), nitrogen oxide (NO), nitrogen dioxide (NO{sub 2}), and hydroxylamine (NH{sub 2}OH) are some of the products of the NH{sub 3}-H{sub 2}O ice radiolysis. The spectral band at 6.85 {mu}m was observed after irradiation of both types of ice. Besides the likely contribution of ammonium (NH{sub 4}{sup +}) and amino (NH{sub 2}) radicals, data suggest a small contribution of NH{sub 2}OH to this band profile after high fluences of irradiation of NH{sub 3}-H{sub 2}O ices. The spectral shift of the NH{sub 3} ''umbrella'' mode (9.3 {mu}m) band is parameterized as a function of NH{sub 3}/H{sub 2}O ratio in amorphous ices. Ammonia and water destruction cross-sections are obtained, as well as the rate of NH{sub 3}-H{sub 2}O (1:10) ice compaction, measured by the OH dangling bond destruction cross-section. Ammonia destruction is enhanced in the presence of H{sub 2}O in the ice and a power law relationship between stopping power and NH{sub 3} destruction cross-section is verified. Such results may provide relevant information for the evolution of molecular species in dense molecular clouds.

  6. ISS Ammonia Leak Detection Through X-Ray Fluorescence

    Science.gov (United States)

    Camp, Jordan; Barthelmy, Scott; Skinner, Gerry

    2013-01-01

    Ammonia leaks are a significant concern for the International Space Station (ISS). The ISS has external transport lines that direct liquid ammonia to radiator panels where the ammonia is cooled and then brought back to thermal control units. These transport lines and radiator panels are subject to stress from micrometeorites and temperature variations, and have developed small leaks. The ISS can accommodate these leaks at their present rate, but if the rate increased by a factor of ten, it could potentially deplete the ammonia supply and impact the proper functioning of the ISS thermal control system, causing a serious safety risk. A proposed ISS astrophysics instrument, the Lobster X-Ray Monitor, can be used to detect and localize ISS ammonia leaks. Based on the optical design of the eye of its namesake crustacean, the Lobster detector gives simultaneously large field of view and good position resolution. The leak detection principle is that the nitrogen in the leaking ammonia will be ionized by X-rays from the Sun, and then emit its own characteristic Xray signal. The Lobster instrument, nominally facing zenith for its astrophysics observations, can be periodically pointed towards the ISS radiator panels and some sections of the transport lines to detect and localize the characteristic X-rays from the ammonia leaks. Another possibility is to use the ISS robot arm to grab the Lobster instrument and scan it across the transport lines and radiator panels. In this case the leak detection can be made more sensitive by including a focused 100-microampere electron beam to stimulate X-ray emission from the leaking nitrogen. Laboratory studies have shown that either approach can be used to locate ammonia leaks at the level of 0.1 kg/day, a threshold rate of concern for the ISS. The Lobster instrument uses two main components: (1) a microchannel plate optic (also known as a Lobster optic) that focuses the X-rays and directs them to the focal plane, and (2) a CCD (charge

  7. Amine substitution into sulfuric acid – ammonia clusters

    Directory of Open Access Journals (Sweden)

    O. Kupiainen

    2011-11-01

    Full Text Available The substitution of ammonia by dimethylamine in sulfuric acid – ammonia – dimethylamine clusters was studied using a collision and evaporation dynamics model. Quantum chemical formation free energies were computed using B3LYP/CBSB7 for geometries and frequencies and RI-CC2/aug-cc-pV(T+dZ for electronic energies. We first demonstrate the good performance of our method by a comparison with an experimental study investigating base substitution in positively charged clusters, and then continue by simulating base exchange in neutral clusters, which cannot be measured directly. Collisions of a dimethylamine molecule with an ammonia containing positively charged cluster result in the instantaneous evaporation of an ammonia molecule, while the dimethylamine molecule remains in the cluster. According to our simulations, a similar base exchange can take place in neutral clusters, although the overall process is more complicated. Neutral sulfuric acid – ammonia clusters are significantly less stable than their positively charged counterparts, resulting in a competition between cluster evaporation and base exchange.

  8. AMMONIA INHIBITION IN THERMOPHILIC ANAEROBIC DIGESTION OF DAIRY CATTLE MANURE

    Directory of Open Access Journals (Sweden)

    S. Sutaryo

    2015-04-01

    Full Text Available This study investigated the effect of five different concentrations of total ammonia nitrogen (TANand free ammonia (FA on the methane yield and digester performance under thermophilic conditions(50°C. Five identical continuously fed digesters were used. The experiment was run for four timeshydraulic retention time (HRT. Data were statitically analysed using the data Analysis Tool Packavailable with the Microsoft Excel program. Different ammonia levels were obtained by pulsing urea toobtain the target level of TAN and FA, and to subsequently maintaining the concentration of ammonialevels by daily urea additions. The result showed a strong negative correlation between both TAN andFA concentrations and methane yield. The methane yield was reduced by 24, 30, 52 and 66% indigesters that had TAN levels of 2.9, 3.6, 4.4 and 5.1 g/L, respectively, corresponding to 0.7, 1.1,1.5 and1.8 g/L FA. Total volatile fatty acid and especially isovaleric and isobutyric acid concentrations wereelevated during ammonia inhibition. Concentration of TAN in the biogas digester exceeding 3 g/Lindicating that very often the full biogas potential is not achieved due to ammonia inhibition and thatlonger HRT should be used to compensate or a lower process temperature should be chosen.

  9. Ammonia modification of oxide-free Si(111) surfaces

    Science.gov (United States)

    Chopra, Tatiana Peixoto; Longo, Roberto C.; Cho, Kyeongjae; Chabal, Yves J.

    2016-08-01

    Amination of surfaces is useful in a variety of fields, ranging from device manufacturing to biological applications. Previous studies of ammonia reaction on silicon surfaces have concentrated on vapor phase rather than wet chemical processes, and mostly on clean Si surfaces. In this work, the interaction of liquid and vapor-phase ammonia is examined on three types of oxide-free surfaces - passivated by hydrogen, fluorine (1/3 monolayer) or chlorine - combining infrared absorption spectroscopy, X-ray photoelectron spectroscopy, and first-principles calculations. The resulting chemical composition highly depends on the starting surface; there is a stronger reaction on both F- and Cl-terminated than on the H-terminated Si surfaces, as evidenced by the formation of Si-NH2. Side reactions can also occur, such as solvent reaction with surfaces, formation of ammonium salt by-products (in the case of 0.2 M ammonia in dioxane solution), and nitridation of silicon (in the case of neat and gas-phase ammonia reactions for instance). Unexpectedly, there is formation of Si-H bonds on hydrogen-free Cl-terminated Si(111) surfaces in all cases, whether vapor phase of neat liquid ammonia is used. The first-principles modeling of this complex system suggests that step-edge surface defects may play a key role in enabling the reaction under certain circumstances, despite the endothermic nature for Si-H bond formation.

  10. Ammonia nanotubes and their interactions with coinage metals

    Energy Technology Data Exchange (ETDEWEB)

    Mohajeri, Afshan, E-mail: amohajeri@shirazu.ac.ir; Bozorgizadeh, Tahereh

    2014-09-30

    Highlights: • The possibility of building ammonia nanotubes (ANTs) is explored. • Six ANTs formed by the stacks of 4- and 5-membered ammonia rings have been studied. • The interactions between the ANTs and coinage metals are investigated. • The nature of nitrogen–metal bonds is unveiled by quantum chemical approaches. - Abstract: The hydrogen bond networks of finite ammonia molecules are considered to explore the possibility of building ammonia nanotubes (ANTs). Six ANTs formed by the stacks of 4- and 5-membered ammonia rings have been studied. The calculated stabilization energies indicate considerable stability for ANTs. In the second part, the interactions between the constructed ANTs and coinage metals (M = Cu, Ag, and Au) are investigated with a focus on the nature of nitrogen…metal bonds. The changes in binding energies from copper to gold reveal that the three metals have almost similar tendency for the interaction with ANTs and the interaction strength is governed by the structure of ANT. Furthermore, the electronic and structural properties of the resulting complexes have been unveiled by means of the quantum chemical analyses. The N…M bonds are found to have partially covalent and partially electrostatic nature.

  11. Development of Ammonia Gas Sensor Using Optimized Organometallic Reagent

    Directory of Open Access Journals (Sweden)

    J. Aubrecht

    2016-01-01

    Full Text Available Reliable, continuous, and spatially distributed monitoring of dangerous or irritating chemical substances belongs to standard functions of contemporary industrial and public security systems. Fiber-optic-based detection provides feasible platform to fulfill such aims. This paper deals with characterization of ammonia sensing elements based on multimode polysiloxane-clad silica-core optical fibers sensitized with 5-(4′-dioctylamino phenylimino quinoline-8-1 cobalt bromide complex reagent immobilized into the cross-linked polymer matrix from a proper mixture of organic solvents and a radical scavenger contributing to the desired long-term stability of optical properties. The applied sensing mechanism combines optical detection principle with chemical reaction of the reagent and ammonia resulting in changes in the visible near-infrared optical absorption spectrum of the cladding layer, influencing via evanescent optical field interactions the spectral distribution of the guided light intensity. Reaction kinetics of short fiber sections exposed to ammonia/nitrogen mixture of various ammonia concentrations is tested and evaluated. The obtained sensitivity, limit of detection, and forward response time of the prepared sensors amount to 1.52⁎10-5 ppm−1, 31 ppm, and 25 s, respectively. The obtained results are promising for fabrication of distributed fiber-optic sensors applicable to detection and location of ammonia gas leaks in industrial as well as general public premises.

  12. Net summertime emission of ammonia from corn and triticale fields

    Science.gov (United States)

    Richter, Undine; Smith, Jeremy; Brümmer, Christian

    2016-04-01

    Recent advancements in laser spectrometry offer new opportunities to investigate ecosystem-atmosphere exchange of environmentally relevant trace gases. In this study, we used a quantum cascade laser (QCL) absorption spectrometer to continuously measure high-frequency concentrations of ammonia and the net exchange between an agricultural site and the atmosphere based on the eddy-covariance approach. The footprint was split into two main sectors, one planted with corn (Zea mays) and the other one with triticale. Ammonia concentrations were highly variable between 2 and almost 100 ppb with an average value of 8.1 ppb during the observation period from April to September 2015. While both deposition and emission of ammonia was observed, the total campaign exchange resulted in a loss of 3.3 kg NH3-N ha-1. Highest average emission fluxes of 65 ng N m-2 s-1 were recorded after fertilization at the beginning of the campaign in April and May. Afterwards the exchange of ammonia with the atmosphere decreased considerably, but the site remained on average a consistent source with sporadic lower peaks and an average flux of 13 ng N m-2 s-1. While management in the form of fertilization was the main driver for ammonia concentration and exchange at the site, biophysical controls from temperature, wind regime, and surface wetness are also presented.

  13. Ammonia disinfection of corn grains intended for ethanol fermentation

    Directory of Open Access Journals (Sweden)

    Magdalena Broda

    2009-12-01

    Full Text Available Background. Bacterial contamination is an ongoing problem for commercial bioethanol plants. It concerns factories using grain and also other raw materials for ethanol fermentation. Bacteria compete with precious yeasts for sugar substrates and micronutrients, secrete lactic and acetic acids, which are toxic for yeast and this competition leads to significant decrease of bioethanol productivity. For this study, bacterial contamination of corn grain was examined. Then the grain was treated by ammonia solution to reduce microbial pollution and after that the microbiological purity of grain was tested one more time. Disinfected and non-disinfected corn grains were ground and fermentation process was performed. Microbiological purity of this process and ethanol yield was checked out. Material and methods. The grain was disinfected by ammonia solution for two weeks. Then the grain was milled and used as a raw material for the ethanol fermentation. The fermentation process was carried out in 500-ml Erlenmeyer flasks. Samples were withdrawn for analysis at 0, 24, 48, 72 hrs. The number of total viable bacteria, lactic acid bacteria, acetic acid bacteria, anaerobic bacteria and the quantity of yeasts and moulds were signified by plate method. Results. Ammonia solution effectively reduces bacterial contamination of corn grain. Mash from grain disinfected by ammonia contains less undesirable microorganisms than mash from crude grain. Moreover, ethanol yield from disinfected grain is at the highest level. Conclusions. The ammonia solution proved to be a good disinfection agent for grain used as a raw material for bioethanol fermentation process.

  14. Mobility Spectrometer Studies on Hydrazine and Ammonia Detection

    Science.gov (United States)

    Niu, William; Eiceman, Gary; Szumlas, Andrew; Lewis, John

    2011-01-01

    An airborne vapor analyzer for detecting sub- to low- parts-per-million (ppm) hydrazine in the presence of higher concentration levels of ammonia has been under development for the Orion program. The detector is based on ambient pressure ionization and ion mobility characterization. The detector encompasses: 1) a membrane inlet to exclude particulate and aerosols from the analyzer inlet; 2) a method to separate hydrazine from ammonia which would otherwise lead to loss of calibration and quantitative accuracy for the hydrazine determination; and 3) response and quantitative determinations for both hydrazine and ammonia. Laboratory studies were made to explore some of these features including mobility measurements mindful of power, size, and weight issues. The study recommended the use of a mobility spectrometer of traditional design with a reagent gas and equipped with an inlet transfer line of bonded phase fused silica tube. The inlet transfer line provided gas phase separation of neutrals of ammonia from hydrazine at 50 C simplifying significantly the ionization chemistry that underlies response in a mobility spectrometer. Performance of the analyzer was acceptable between ranges of 30 to 80 C for both the pre-fractionation column and the drift tube. An inlet comprised of a combined membrane with valve-less injector allowed high speed quantitative determination of ammonia and hydrazine without cross reactivity from common metabolites such as alcohols, esters, and aldehydes. Preliminary test results and some of the design features are discussed.

  15. Different cultivation methods to acclimatise ammonia-tolerant methanogenic consortia.

    Science.gov (United States)

    Tian, Hailin; Fotidis, Ioannis A; Mancini, Enrico; Angelidaki, Irini

    2017-02-11

    Bioaugmentation with ammonia tolerant-methanogenic consortia was proposed as a solution to overcome ammonia inhibition during anaerobic digestion process recently. However, appropriate technology to generate ammonia tolerant methanogenic consortia is still lacking. In this study, three basic reactors (i.e. batch, fed-batch and continuous stirred-tank reactors (CSTR)) operated at mesophilic (37°C) and thermophilic (55°C) conditions were assessed, based on methane production efficiency, incubation time, TAN/FAN (total ammonium nitrogen/free ammonia nitrogen) levels and maximum methanogenic activity. Overall, fed-batch cultivation was clearly the most efficient method compared to batch and CSTR. Specifically, by saving incubation time up to 150%, fed-batch reactors were acclimatised to nearly 2-fold higher FAN levels with a 37%-153% methanogenic activity improvement, compared to batch method. Meanwhile, CSTR reactors were inhibited at lower ammonia levels. Finally, specific methanogenic activity test showed that hydrogenotrophic methanogens were more active than aceticlastic methanogens in all FAN levels above 540mgNH3-NL(-1).

  16. Effect of ammonia-generating diet on ovine serum and follicular fluid ammonia and urea levels, serum oestrogen and progesterone concentrations and granulosa cell functions.

    Science.gov (United States)

    Nandi, S; Mondal, S; Pal, D T; Gupta, P S P

    2016-04-01

    This study was undertaken to elucidate the effect of ammonia-generating diet on serum and follicular fluid ammonia and urea levels, serum oestrogen and progesterone concentrations and granulosa cell growth and secretion parameters in ewes (Ovis aries). Ewes were fed with 14% CP diet (control) or ammonia-generating diet or ammonia-generating diet plus soluble sugar. The serum and follicular fluid ammonia and urea level, serum oestrogen and progesterone levels and granulosa cell (obtained from ovaries of slaughtered ewes) growth parameters and secretory activities were estimated. Ammonia-generating diet (high-protein diet) increased the serum ammonia and urea concentration. Supplementation of soluble sugar significantly reduced the ammonia concentration in serum with comparable levels as in control group; however, the urea level in the same group was higher than that observed in control group. Supplementation of soluble sugar significantly reduced the follicular fluid ammonia concentration; however, the level was significantly higher compared to control group. Supplementation of soluble sugar brought down the follicular fluid urea level comparable to that observed in control group. Oestrogen and progesterone levels remained unchanged in ewes fed with different types of diet. Oestrogen and progesterone secretion were significantly lowered from granulosa cells recovered from ewes fed with high ammonia-generating diet. Low metabolic activity and high incidence of apoptosis were observed in granulosa cells obtained from ovaries of ewes fed with ammonia-generating diet.

  17. Branched-chain amino acids increase arterial blood ammonia in spite of enhanced intrinsic muscle ammonia metabolism in patients with cirrhosis and healthy subjects

    DEFF Research Database (Denmark)

    Dam, Gitte; Keiding, Susanne; Munk, Ole Lajord

    2011-01-01

    Branched-chain amino acids (BCAA) are used in attempts to reduce blood ammonia in patients with cirrhosis and intermittent hepatic encephalopathy based on the hypothesis that BCAA stimulate muscle ammonia detoxification. We studied the effects of an oral dose of BCAA on the skeletal muscle...... the metabolism of blood-supplied ammonia and the A-V measurements were used to measure the total ammonia metabolism across the thigh muscle. After intake of BCAA, blood ammonia increased more than 30% in both groups of subjects (both P ....05). BCAA intake led to a massive glutamine release from the muscle (cirrhotic patients, P BCAA enhanced the intrinsic muscle metabolism of ammonia but not the metabolism of blood-supplied ammonia in both the patients with cirrhosis and in the healthy...

  18. Dynamics of ammonia metabolism in man

    Energy Technology Data Exchange (ETDEWEB)

    Lockwood, J.S.; McDonald, J.M.; Reiman, R.E.; Gelbard, A.S.; Laughlin, J.S.; Duffy, T.E.; Plum, F.

    1977-01-01

    The cyclotron-produced radionuclide /sup 13/N, T/sub 1/2/ 10 min, was used to label NH/sub 3/ and study its metabolism in 5 normal subjects and 17 with liver disease, including 5 with portacaval shunts, and 11 with encephalopathy (HE). The arterial NH/sub 3/ levels were 100 +- 8 ..mu..M in the non-HE subjects and 149 +- 18 ..mu..M in those with HE, (P < 0.01). After an iv pulse of 10 mCi of carrier-free /sup 13/NH/sub 4/Cl, the rate of NH/sub 3/ clearance from the vascular compartment was a function of its arterial concentration: ..mu..mol/min = 4.71 (NH/sub 3/)/sub a/ + 3.76 (r = +0.85, P < 0.005). In all subjects, brain activity increased rapidly when the specific activity of arterial NH/sub 3/ was maximal, and plateaued at levels 5.1 times those due to an equivalent amount of blood, indicating rapid passage of NH/sub 3/ across the blood-brain barrier, followed by metabolic trapping. Quantitative body scans showed that 7.4 +- 0.3% of observed activity was trapped by the brain. The brain NH/sub 3/ utilization rate (BAUR), calculated from brain and blood activities, was a function of (NH/sub 3/)/sub a/: ..mu..mol/min = 0.32 (NH/sub 3/)/sub a/ + 1.8 (r = +0.93, P < 0.005). The BAUR was 34 +- 3 ..mu..mol/min in the non-HE subjects and 49 +- 6 in those with HE (P < 0.05). Assuming a normal cerebral blood flow and brain weight, 51 +- 4% of arterial NH/sub 3/ was extracted from the blood during a single pass through normal brains. Utilization was greatest in grey matter. Calculations show that NH/sub 3/ metabolism occurs in a compartment, perhaps in astrocytes, that contains less than 20% of all brain ammonia. Liver uptake (3 to 24%) was a function of its projected size on the scan. Skeletal muscle metabolized about 50% of the arterial NH/sub 3/ in normals, less in those with cachexia.

  19. Solvent-assistant self-assembly of an AIE+TICT fluorescent Schiff base for the improved ammonia detection.

    Science.gov (United States)

    Han, Tianyu; Wei, Wei; Yuan, Jing; Duan, Yuai; Li, Yaping; Hu, Liangyu; Dong, Yuping

    2016-04-01

    Solvent-assistant self-assembly of an AIE+TICT fluorescent Schiff base into one-dimensional nanofilaments has been developed. The orientation of the assemblies can be controlled by a simple dewetting process: the filaments are interweaved when the self-assembly process is performed on a horizontal substrate, while tilting the substrate to a tiny angle results in the formation of highly oriented ones with long-range order as verified by microscopic examination. The compound shows remarkable fluorescent response to ammonia gas based on a TICT-LE transition. The self-assembled film presents higher detection sensitivity compared with the non-assembled test paper: the former enables 4.75 times faster response time and 6.86 times lower detection limit than the latter. Furthermore, the former demonstrates better selectivity toward ammonia gas in the presence of various organic amines. The sensing devices also enjoy the advantage of cyclic utilization. The fluorescence of the fumed devices can be converted back into the original state when they are heated at 100 °C for 5 min, as thermal treatment can desorb the ammonia gas that adsorbed in the sensing devices.

  20. An anoxic-aerobic system for simultaneous biodegradation of phenol and ammonia in a sequencing batch reactor.

    Science.gov (United States)

    Liu, Qifeng; Singh, Vijay P; Fu, Zhimin; Wang, Jing; Hu, La

    2017-03-24

    A laboratory-scale sequencing batch reactor (SBR) was investigated to treat artificial pretreated coal gasification wastewater that was mainly contained of ammonia and phenol. The efficiency of SBR fed with increasing phenol concentrations (from 150 to 300 mg l(-1)) and the relationship among phenol, nitrogen removal, and the microbial community structure were evaluated. When the phenol feeding concentration was increased to about 300 mg l(-1), the removal efficiency was above 99.0%, demonstrating the robustness of phenol removal capacity. The study showed that most phenol was degraded in anoxic stage. The average removal efficiencies of ammonia and total nitrogen were 98.4 and 81.9%, respectively, with average NH4(+)-N concentration of 107.5 mg l(-1) and COD/N 7.5. Low temperature caused sludge loss that led to the decreased performance. Increasing the temperature could not recover the performance effectively. The data from bacterial analysis revealed that Delftia, Hydrogenophaga, and unclassified Xanthomonadaceae played a significant role in phenol degradation before the temperature increase, while uncultured Syntrophococcus sp. and unclassified Rhodocyclaceae were responsible for phenol degradation after the temperature increase. These results imply that the SBR holds potential for the simultaneous removal of phenolic compounds and nitrogen through aerobic ammonia oxidation and anoxic denitrification with phenol as the co-organic carbon source.

  1. Development of a general non-noble metal catalyst for the benign amination of alcohols with amines and ammonia.

    Science.gov (United States)

    Cui, Xinjiang; Dai, Xingchao; Deng, Youquan; Shi, Feng

    2013-03-11

    The N-alkylation of amines or ammonia with alcohols is a valuable route for the synthesis of N-alkyl amines. However, as a potentially clean and economic choice for N-alkyl amine synthesis, non-noble metal catalysts with high activity and good selectivity are rarely reported. Normally, they are severely limited due to low activity and poor generality. Herein, a simple NiCuFeOx catalyst was designed and prepared for the N-alkylation of ammonia or amines with alcohol or primary amines. N-alkyl amines with various structures were successfully synthesized in moderate to excellent yields in the absence of organic ligands and bases. Typically, primary amines could be efficiently transformed into secondary amines and N-heterocyclic compounds, and secondary amines could be N-alkylated to synthesize tertiary amines. Note that primary and secondary amines could be produced through a one-pot reaction of ammonia and alcohols. In addition to excellent catalytic performance, the catalyst itself possesses outstanding superiority, that is, it is air and moisture stable. Moreover, the magnetic property of this catalyst makes it easily separable from the reaction mixture and it could be recovered and reused for several runs without obvious deactivation.

  2. Determination of ammonia in ethylene using ion mobility spectrometry

    Science.gov (United States)

    Cross, J. H.; Limero, T. F.; Lane, J. L.; Wang, F.

    1997-01-01

    A simple procedure to analyze ammonia in ethylene by ion mobility spectrometry is described. The spectrometer is operated with a silane polymer membrane., 63Ni ion source, H+ (H2O)n reactant ion, and nitrogen drift and source gas. Ethylene containing parts per billion (ppb) (v/v) concentrations of ammonia is pulled across the membrane and diffuses into the spectrometer. Preconcentration or preseparation is unnecessary, because the ethylene in the spectrometer has no noticeable effect on the analytical results. Ethylene does not polymerize in the radioactive source. Ethylene's flammability is negated by the nitrogen inside the spectrometer. Response to ammonia concentrations between 200 ppb and 1.5 ppm is near linear, and a detection limit of 25 ppb is calculated.

  3. The Measuring Ammonia in Nature (MAN network in the Netherlands

    Directory of Open Access Journals (Sweden)

    D. E. Lolkema

    2015-04-01

    Full Text Available Since 2005 the Measuring Ammonia in Nature (MAN network monitors atmospheric ammonia concentrations in nature reserve areas in the Netherlands (man.rivm.nl. The main aim of the network is to monitor national trends, to assess regional deviations and to validate model calculations. Measurements are performed with commercial passive samplers, monthly calibrated against ammonia measurements of active sampling devices. The sampling is performed by an extensive group of local volunteers, which minimizes the cost and enables the use of local knowledge. We show the MAN network to be well capable of monitoring trends on national and local scale, as well as providing data for more detailed local analyses. The quality of the network is such that trends over time for individual MAN areas can be detected in the order of 3% per year for time series of six to nine years.

  4. Novel Ru - K/Carbon Nanotubes Catalyst for Ammonia Synthesis

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A novel ammonia synthesis catalyst, potassium-promoted ruthenium supported on carbon nanotubes, was developed. It was found that the Ru-K/carbon nanotubes catalyst had higher activity for ammonia synthesis ( 20.85 ml NH 3 /h/g-cat ) than the Ru-K/fullerenes ( 13.3 ml NH 3 /h/g-cat ) at atmospheric ressure and 623 K. The catalyst had activity even at 473 K, and had the highest activity ( 23.46 ml NH 3 /h/g-cat ) at 643 K. It was suggested that the multi-walled structure favored the electron transfer, the hydrogen-storage and the hydrogen-spill which were favorable to ammonia synthesis.

  5. Ammonia nanotubes and their interactions with coinage metals

    Science.gov (United States)

    Mohajeri, Afshan; Bozorgizadeh, Tahereh

    2014-09-01

    The hydrogen bond networks of finite ammonia molecules are considered to explore the possibility of building ammonia nanotubes (ANTs). Six ANTs formed by the stacks of 4- and 5-membered ammonia rings have been studied. The calculated stabilization energies indicate considerable stability for ANTs. In the second part, the interactions between the constructed ANTs and coinage metals (M = Cu, Ag, and Au) are investigated with a focus on the nature of nitrogen…metal bonds. The changes in binding energies from copper to gold reveal that the three metals have almost similar tendency for the interaction with ANTs and the interaction strength is governed by the structure of ANT. Furthermore, the electronic and structural properties of the resulting complexes have been unveiled by means of the quantum chemical analyses. The N…M bonds are found to have partially covalent and partially electrostatic nature.

  6. Design Ammonia Gas Detection System by Using Optical Fiber Sensor

    Directory of Open Access Journals (Sweden)

    Dr. Bushra. R. Mhdi

    2013-07-01

    Full Text Available Design study and construction of Ammonia gas detection using a fiber as a sensor to based on evanescent wave sensing technique was investigated. Multi-mode fiber type (PCS with core diameter (600μm and (50cm length used where plastic clad was removed by chemical etching for effective sensing area which coated with sol-gel film to enhance its absorption characteristics to evanescent wave around the optical spectrum emitted from halogen lamp measurements through different temperature rang (25-60oc with and without air using as a carrier to ammonia molecules are investigated. Finally sensing efficiency are monitored to ammonia gas it affected to different temperature and environmental condition are studied and our result are compatible to scientific publishes

  7. AMMONOX-Ammonia for enhancing biogas yield & reducing NOx

    DEFF Research Database (Denmark)

    Gavala, Hariklia N.; Kristensen, P.G.; Paamand, K.;

    2013-01-01

    , biogas plants digesting liquid manure alone are not economically viable due to the relatively low organic content of the manure, usually 3-5%.Thus, their economical profitable operation relies partly on increasing the methane yield from manure, and especially of its solid fraction, usually called...... to be emphasized that apart the increased methane yield, the ammonia used can be recovered and recycled from the liquid manure resulting in no consumption of chemicals and actually in production of excess ammonia. AMMONOX is an innovative concept focusing on an integrated approach for sustainable and cost......-efficient energy production in the form of methane from manure. The three pillars of AMMONOX are a) the optimisation and application of Aqueous Ammonia Soaking (AAS) as a moderate and sustainable chemical treatment for enhanced methane production from manure fibers and lignocellulosic biomasses, b) the application...

  8. Ammonia-oxidizing archaea have better adaptability in oxygenated/hypoxic alternant conditions compared to ammonia-oxidizing bacteria.

    Science.gov (United States)

    Liu, Shuai; Hu, Baolan; He, Zhanfei; Zhang, Bin; Tian, Guangming; Zheng, Ping; Fang, Fang

    2015-10-01

    Ammonia oxidation is performed by both ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB). Few studies compared the adaptability of AOA and AOB for oxygenated/hypoxic alternant conditions in water-level-fluctuating zones. Here, using qPCR and 454 high-throughput sequencing of functional amoA genes of AOA and AOB, we examined the changes of abundances, diversities, and community structures of AOA and AOB in periodically flooded soils compared to the non-flooded soils in Three Gorges Reservoir. The increased AOA operational taxonomic unit (OTU) numbers and the higher ratios of abundance (AOA:AOB) in the periodically flooded soils suggested AOA have better adaptability for oxygenated/hypoxic alternant conditions in the water-level-fluctuating zones in the Three Gorges Reservoir and probably responsible for the ammonia oxidation there. Canonical correspondence analysis (CCA) showed that oxidation-reduction potential (ORP) had the most significant effect on the community distribution of AOA (p ammonia-oxidizing microbes. ORP was significantly negatively correlated with AOA OTU numbers (p < 0.05), ratio of OTU numbers (AOA:AOB) (p < 0.01), and ratio of amoA gene abundances (AOA:AOB) (p < 0.05). ORP was also significantly positively correlated with AOB abundance (p < 0.05).

  9. Growth of ammonia-oxidizing archaea and bacteria in cattle manure compost under various temperatures and ammonia concentrations.

    Science.gov (United States)

    Oishi, Ryu; Tada, Chika; Asano, Ryoki; Yamamoto, Nozomi; Suyama, Yoshihisa; Nakai, Yutaka

    2012-05-01

    A recent study showed that ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) coexist in the process of cattle manure composting. To investigate their physiological characteristics, liquid cultures seeded with fermenting cattle manure compost were incubated at various temperatures (37°C, 46°C, or 60°C) and ammonium concentrations (0.5, 1, 4, or 10 mM NH (4) (+) -N). The growth rates of the AOB and AOA were monitored using real-time polymerase chain reaction analysis targeting the bacterial and archaeal ammonia monooxygenase subunit A genes. AOB grew at 37°C and 4 or 10 mM NH (4) (+) -N, whereas AOA grew at 46°C and 10 mM NH (4) (+) -N. Incubation with allylthiourea indicated that the AOB and AOA grew by oxidizing ammonia. Denaturing gradient gel electrophoresis and subsequent sequencing analyses revealed that a bacterium related to Nitrosomonas halophila and an archaeon related to Candidatus Nitrososphaera gargensis were the predominant AOB and AOA, respectively, in the seed compost and in cultures after incubation. This is the first report to demonstrate that the predominant AOA in cattle manure compost can grow and can probably oxidize ammonia under moderately thermophilic conditions.

  10. Acidification Enhances Hybrid N2O Production Associated with Aquatic Ammonia-Oxidizing Microorganisms

    Science.gov (United States)

    Frame, Caitlin H.; Lau, Evan; Nolan, E. Joseph; Goepfert, Tyler J.; Lehmann, Moritz F.

    2017-01-01

    Ammonia-oxidizing microorganisms are an important source of the greenhouse gas nitrous oxide (N2O) in aquatic environments. Identifying the impact of pH on N2O production by ammonia oxidizers is key to understanding how aquatic greenhouse gas fluxes will respond to naturally occurring pH changes, as well as acidification driven by anthropogenic CO2. We assessed N2O production rates and formation mechanisms by communities of ammonia-oxidizing bacteria (AOB) and archaea (AOA) in a lake and a marine environment, using incubation-based nitrogen (N) stable isotope tracer methods with 15N-labeled ammonium (15NH4+) and nitrite (15NO2−), and also measurements of the natural abundance N and O isotopic composition of dissolved N2O. N2O production during incubations of water from the shallow hypolimnion of Lake Lugano (Switzerland) was significantly higher when the pH was reduced from 7.54 (untreated pH) to 7.20 (reduced pH), while ammonia oxidation rates were similar between treatments. In all incubations, added NH4+ was the source of most of the N incorporated into N2O, suggesting that the main N2O production pathway involved hydroxylamine (NH2OH) and/or NO2− produced by ammonia oxidation during the incubation period. A small but significant amount of N derived from exogenous/added 15NO2− was also incorporated into N2O, but only during the reduced-pH incubations. Mass spectra of this N2O revealed that NH4+ and 15NO2− each contributed N equally to N2O by a “hybrid-N2O” mechanism consistent with a reaction between NH2OH and NO2−, or compounds derived from these two molecules. Nitrifier denitrification was not an important source of N2O. Isotopomeric N2O analyses in Lake Lugano were consistent with incubation results, as 15N enrichment of the internal N vs. external N atoms produced site preferences (25.0–34.4‰) consistent with NH2OH-dependent hybrid-N2O production. Hybrid-N2O formation was also observed during incubations of seawater from coastal Namibia

  11. Excretory nitrogen metabolism and defence against ammonia toxicity in air-breathing fishes.

    Science.gov (United States)

    Chew, S F; Ip, Y K

    2014-03-01

    With the development of air-breathing capabilities, some fishes can emerge from water, make excursions onto land or even burrow into mud during droughts. Air-breathing fishes have modified gill morphology and morphometry and accessory breathing organs, which would tend to reduce branchial ammonia excretion. As ammonia is toxic, air-breathing fishes, especially amphibious ones, are equipped with various strategies to ameliorate ammonia toxicity during emersion or ammonia exposure. These strategies can be categorized into (1) enhancement of ammonia excretion and reduction of ammonia entry, (2) conversion of ammonia to a less toxic product for accumulation and subsequent excretion, (3) reduction of ammonia production and avoidance of ammonia accumulation and (4) tolerance of ammonia at cellular and tissue levels. Active ammonia excretion, operating in conjunction with lowering of ambient pH and reduction in branchial and cutaneous NH₃ permeability, is theoretically the most effective strategy to maintain low internal ammonia concentrations. NH₃ volatilization involves the alkalization of certain epithelial surfaces and requires mechanisms to prevent NH₃ back flux. Urea synthesis is an energy-intensive process and hence uncommon among air-breathing teleosts. Aestivating African lungfishes detoxify ammonia to urea and the accumulated urea is excreted following arousal. Reduction in ammonia production is achieved in some air-breathing fishes through suppression of amino acid catabolism and proteolysis, or through partial amino acid catabolism leading to alanine formation. Others can slow down ammonia accumulation through increased glutamine synthesis in the liver and muscle. Yet, some others develop high tolerance of ammonia at cellular and tissue levels, including tissues in the brain. In summary, the responses of air-breathing fishes to ameliorate ammonia toxicity are many and varied, determined by the behaviour of the species and the nature of the environment in

  12. Diffusion equilibrium for ammonia in the kidney of the acidotic dog.

    Science.gov (United States)

    Stone, W J; Balagura, S; Pitts, R F

    1967-10-01

    Inflow of preformed ammonia in arterial blood, renal production of ammonia, outflow of ammonia in renal venous blood, and urinary excretion of ammonia were measured during the infusion of (15)NH(4)Cl into one renal artery of dogs with chronic metabolic acidosis. Our results show that the specific activity of ammonia measured in the urine and that calculated in the renal pool agree within 95%. Pool specific activity is obtained by dividing the rate of infusion of isotope by the pool turnover rate, i.e., the sum of the rate of ammonia output in the urine and that in renal venous blood. An average of 35% of urinary ammonia is derived from arterial ammonia in these experiments. We conclude that ammonia is distributed evenly throughout all phases of the kidney within a period less than the transit time of blood through the kidney. Furthermore, from the proportion of urinary ammonia we found to be derived from preformed arterial ammonia (35%), and from our previous demonstration that 73% of urinary ammonia derives from deamidation and/or deamination of plasma glutamine, alanine, glycine, and glutamate, we can account for all of the ammonia that leaves the kidney in renal venous blood and in urine.

  13. Ammonia adsorption and its effects on framework stability of MOF-5 and MOF-177.

    Science.gov (United States)

    Saha, Dipendu; Deng, Shuguang

    2010-08-15

    Ammonia adsorption equilibrium and kinetics on MOF-5 and MOF-177 were measured volumetrically at 298 K and ammonia pressures up to 800 torr. This study allowed us to determine the ammonia adsorption properties and stability of both MOFs after exposure to ammonia. MOF-177 adsorbed more ammonia than MOF-5 at ammonia pressures below 150 torr and the ammonia adsorption capacity on both MOFs at 800 torr was about the same (12.2 mmol/g). It can be inferred from the adsorption results that physical adsorption of ammonia on both MOFs dominated at ammonia pressures below 150 torr after which chemical reactions between ammonia and MOF frameworks take place. After exposure to ammonia both MOFs lost majority of their pore textures as evidenced by a drastic decrease of specific surface area and pore volume. The X-ray diffraction study suggested a complete loss of crystallinity of both MOFs, and the FT-IR and Raman spectral analyses showed the generation of free organic ligands within both MOF-5 and MOF-177 after they were exposed to ammonia. Ammonia molecules are proposed to destroy the MOF frameworks by forming hydrogen bonds with Zn(4)O clusters of MOFs.

  14. Mitigating ammonia and volatile organic compounds (VOCs) emissions from poultry houses using vegetative environmental buffers

    Science.gov (United States)

    The expansion of the poultry industry due to the growing demand of livestock products is putting considerable stress on the atmospheric environment and is also a public health concern. While many regulators and researchers identify land-applied poultry manure as a source of air pollutants, less is k...

  15. Investigating the Efficiency of Biological Filters for Ammonia Removal

    Directory of Open Access Journals (Sweden)

    S Motesaddi Zarandi, MR Massoudinejad, A Mazaheri Tehrani, H Pouri

    2013-09-01

    Full Text Available Backgrounds and Aims: Ammonia removal from air to prevent severe damage to the environment and living organisms is very important. Biofiltration is an efficient, easy, cost-effective, and environmentally friendly process for degradation of ammonia from waste air. The aim of this study is to investigate the efficiency of biological filtration using a compost and scallop bed for ammonia removal. Materials and Methods: According to the ammonia removal method a column with 14cm inner diameter and 45cm height made from transparent Plexiglas was used. The column was filled up to 25 cm with compost and scallop (with a scallop: compost ratio of 1:4. In this study, performance of the biofilter was studied under 10 different flow rates (1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 lit/min and 5 different concentrations (0-20, 20-40, 40-60, 60-80 and 80-100 ppm at a temperature of 25 degrees Celsius. Results: The results of this study showed that efficiency is decreased when the flow rate or concentration is increased because the microbial population is reduced. The efficiency was reduced by 84.6-98.2 percent. Maximum efficiency occurred at a 0.19g/(m3.h loading rate. Efficiency was in 0-20 concentration intervals at a flow rate of 1 lit/min and at an Empty Bed Residence Time (EBRT of 240 seconds. Conclusion: The results show that a biofilter with a compost and scallop bed is efficient for ammonia removal from air. Results can be optimized in the design and operation of biological systems to be used in the industrial control of ammonia gas.

  16. Electrochemically driven extraction and recovery of ammonia from human urine.

    Science.gov (United States)

    Luther, Amanda K; Desloover, Joachim; Fennell, Donna E; Rabaey, Korneel

    2015-12-15

    Human urine contains high concentrations of nitrogen, contributing about 75% of the nitrogen in municipal wastewaters yet only 1% of the volume. Source separation of urine produces an ideal waste stream for nitrogen and phosphorus recovery, reducing downstream costs of nutrient treatment at wastewater treatment facilities. We examined the efficiency and feasibility of ammonia extraction and recovery from synthetic and undiluted human urine using an electrochemical cell (EC). EC processing of synthetic urine produced an ammonium flux of 384 ± 8 g N m(-2) d(-1) with a 61 ± 1% current efficiency at an energy input of 12 kWh kg(-1) N removed. EC processing of real urine displayed similar performance, with an average ammonium flux of 275 ± 5 g N m(-2) d(-1) sustained over 10 days with 55 ± 1% current efficiency for ammonia and at an energy input of 13 kWh kg(-1) N removed. With the incorporation of an ammonia stripping and absorption unit into the real urine system, 57 ± 0.5% of the total nitrogen was recovered as ammonium sulfate. A system configuration additionally incorporating stripping of the influent headspace increased total nitrogen recovery to 79% but led to reduced performance of the EC as the urine ammonium concentration decrease. Direct stripping of ammonia (NH3) from urine with no chemical addition achieved only 12% total nitrogen recovery at hydraulic retention times comparable with the EC systems. Our results demonstrate that ammonia can be extracted via electrochemical means at reasonable energy inputs of approximately 12 kWh kg(-1) N. Considering also that the hydrogen generated is worth 4.3 kWh kg(-1) N, the net electrical input for extraction becomes approximately 8 kWh kg(-1) N if the hydrogen can be used. Critical for further development will be the inclusion of a passive means for ammonia stripping to reduce additional energy inputs.

  17. First detection of ammonia (NH3) in the upper troposphere

    Science.gov (United States)

    Höpfner, Michael; Volkamer, Rainer; Grabowski, Udo; Grutter de la Mora, Michel; Orphal, Johannes; Stiller, Gabriele; von Clarmann, Thomas

    2016-04-01

    Ammonia (NH3) is the major alkaline trace gas in the troposphere. Neutralization of atmospheric acids, like HNO3 and H2SO4, leads to formation of ammonium nitrate and ammonium sulfate aerosols. Further, there are indications that NH3 may enhance nucleation of sulfuric acid aerosols by stabilization of sulfuric acid clusters. By far the largest source of ammonia is agricultural food production. Major global emissions are located in S-E Asia as e.g. shown by satellite nadir observations. Besides its importance with respect to air quality issues, an increase of ammonia emissions in the 21st century might lead to a significant climate radiative impact through aerosol formation. In spite of its significance, there is a lack of observational information on the global distribution of NH3 in the mid- and upper troposphere. Observational evidence, however, would be important for testing e.g. model results on the fate of ammonia from its source regions on ground to altitudes up to the tropopause. In this contribution we will show, to our knowledge, the first unequivocal detection of ammonia in the upper troposphere. This result has been achieved through analysis of infrared limb-emission observations performed with the MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) instrument on board the Envisat satellite from 2002-2012. On a global scale, enhanced values of ammonia have been measured in the upper tropospheric region influenced by the Asian monsoon. We will present a quantitative analysis of the retrieved concentrations of NH3 including an error assessment and further retrieval diagnostics. The results will be discussed with respect to the variability of NH3 locally within the Asian monsoon region's upper troposphere and at different years. Further, we will show comparisons between global distributions of NH3 from published model simulations and our observational dataset from MIPAS.

  18. Test and Analysis for Spraying Ammonia in Diesel Engine

    Institute of Scientific and Technical Information of China (English)

    周华祥; 刘敬平; 贺力克; 陈方; 申奇志; 骆锐; 周正

    2011-01-01

    A certain amount of ammonia reducer were directly injected into the 4102BZLQ Diesel engine' s combustion chamber when the combustion temperature decreases to 1 573 - 1 073 K, NOx generated could be reduced to 1.11 g/( kW· h). Based on PRF combustion mechanism, NO was tested by using the heavy-duty diesel engine test cycle of ESC thirteen conditions , the ammonia spray angle and amount were tested and optimized in different conditions. The test results show that the thermal efficiency of Diesel engine does not decrease while NO exhaust decreases.

  19. Lanthanum-Promoted Ru/Sepiolite in Ammonia Synthesis

    Institute of Scientific and Technical Information of China (English)

    Le Zhiping; Lin Jianxin; Yu Xiujin; Huang Yueyu; Wei Kemei

    2005-01-01

    A new kind of Ru supported on sepiolite catalyst with La as promoter for ammonia synthesis was prepared. The effects of reaction conditions on catalytic activity were discussed. The result shows that La is an effective promoter for sepiolite-supported Ru based catalyst. When the load of Ru is 5% (mass fraction), and the molar ratio of La/Ru is 1.5, under the condition of 10 MPa 450 ℃ 20000 h-1, the ammonia synthesis rate is 38.5 mmol NH3·g-1·h-1.

  20. Photoacoustic spectroscopy for fast and sensitive ammonia detection

    Institute of Scientific and Technical Information of China (English)

    Wang Zhang; Zhiying Wu; Qingxu Yu

    2007-01-01

    A photoacoustic (PA) spectrometer with H-type first longitudinal resonant cells for ammonia detection is developed. A new PA cell structure is designed to accelerate the drift velocity of the sample gas near the cell surface, so that the short response time at the flow rate of 100 sccm (standard cubic centimeter per minute) is achieved. The response time of 5 min and detection limit of 0.86 ppbv is reached for ammonia concentration measurement with a Teflon polytetrafluoroethylene (PTFE) cell. Further improvement could be expected when using a brass cell with a high quality Teflon fluorinated ethylene propylene (FEP) coating.

  1. Power cycles with ammonia-water mixtures as working fluid

    Energy Technology Data Exchange (ETDEWEB)

    Thorin, Eva

    2000-05-01

    It is of great interest to improve the efficiency of power generating processes, i.e. to convert more of the energy in the heat source to power. This is favorable from an environmental point of view and can also be an economic advantage. To use an ammonia-water mixture instead of water as working fluid is a possible way to improve the efficiency of steam turbine processes. This thesis includes studies of power cycles with ammonia-water mixtures as working fluid utilizing different kinds of heat sources for power and heat generation. The thermophysical properties of the mixture are also studied. They play an important role in the calculations of the process performance and for the design of its components, such as heat exchangers. The studies concern thermodynamic simulations of processes in applications suitable for Swedish conditions. Available correlations for the thermophysical properties are compared and their influence on simulations and heat exchanger area predictions is investigated. Measurements of ammonia-water mixture viscosities using a vibrating wire viscometer are also described. The studies performed show that power cycles with ammonia-water mixtures as the working fluid are well suited for utilization of waste heat from industry and from gas engines. The ammonia-water power cycles can give up to 32 % more power in the industrial waste heat application and up to 54 % more power in the gas engine bottoming cycle application compared to a conventional Rankine steam cycle. However, ammonia-water power cycles in small direct-fired biomass-fueled cogeneration plants do not show better performance than a conventional Rankine steam cycle. When different correlations for the thermodynamic properties are used in simulations of a simple ammonia-water power cycle the difference in efficiency is not larger than 4 %, corresponding to about 1.3 percentage points. The differences in saturation properties between the correlations are, however, considerable at high

  2. Crystal Structure of an Ammonia-Permeable Aquaporin

    DEFF Research Database (Denmark)

    Kirscht, Andreas; Kaptan, Shreyas S; Bienert, Gerd Patrick;

    2016-01-01

    the structure determined at 1.18 Å resolution from twinned crystals of Arabidopsis thaliana aquaporin AtTIP2;1 and confirm water and ammonia permeability of the purified protein reconstituted in proteoliposomes as further substantiated by molecular dynamics simulations. The structure of AtTIP2;1 reveals...... an extended selectivity filter with the conserved arginine of the filter adopting a unique unpredicted position. The relatively wide pore and the polar nature of the selectivity filter clarify the ammonia permeability. By mutational studies, we show that the identified determinants in the extended selectivity...

  3. Efficiency of deodorant materials for ammonia reduction in indoor air

    DEFF Research Database (Denmark)

    Bivolarova, Mariya Petrova; Mizutani, Chiyomi; Melikov, Arsen Krikor;

    2014-01-01

    A comparative study about the removability of ammonia gas in the air by activated carbon fiber (ACF) felt chemically treated with acid and a cotton fabric processed with iron phthalocyanine with copper (Cu) was performed in small-scale experiments. The test rig consisted of a heated plate and its...... proved activated carbon fiber felt with acid to be highly efficient in removing ammonia gas. Air temperature did not have profound effect on ACF performance. However, efficiency of the carbon fiber felt decreased when relative humidity was raised from 20 to 80%....

  4. Reactive uptake of ammonia to secondary organic aerosols: kinetics of organonitrogen formation

    Directory of Open Access Journals (Sweden)

    Y. Liu

    2015-06-01

    Full Text Available As a class of brown carbon, organonitrogen compounds originating from the heterogeneous uptake of NH3 by secondary organic aerosol (SOA have received significant attention recently. In the current work, particulate organonitrogen formation during the ozonolysis of α-pinene and the OH oxidation of m-xylene in the presence of ammonia (34–125 ppb is studied in a smog chamber equipped with a High Resolution Time-of-Flight Aerosol Mass Spectrometer and a Quantum Cascade Laser instrument. A large diversity of nitrogen containing organic (NOC fragments was observed which were consistent with the reaction of ammonia with carbonyl containing SOA. The uptake coefficients of NH3 to SOA leading to organonitrogen compounds are reported for the first time and were in the range of ∼ 10-3–10-2, decreasing significantly to -5 after 6 h of reaction. At the end of experiments (∼ 6 h the NOC mass contributed 8.9 ± 1.7 and 31.5 ± 4.4 wt% to the total α–pinene and m-xylene derived SOA, and 4–15 wt% of the total nitrogen in the system. Uptake coefficients were also found to be positively correlated with particle acidity and negatively correlated with NH3 concentration, indicating that heterogeneous reactions were responsible for the observed NOC mass, possibly limited by liquid phase diffusion. Under these conditions, the data also indicate that the formation of NOC can compete kinetically with inorganic acid neutralization. The formation of NOC in this study suggests that a significant portion of the ambient particle associated N may be derived from NH3 heterogeneous reactions with SOA. NOC from such a mechanism may be an important and unaccounted for source of PM associated nitrogen, and a mechanism for medium or long-range transport and dry/wet deposition of atmospheric nitrogen.

  5. MEASUREMENT OF AMMONIA EMISSIONS FROM MECHANICALLY VENTILATED POULTRY HOUSES USING MULTIPATH TUNABLE DIODE LASER SPECTROSCOPY

    Science.gov (United States)

    Ammonia emissions from mechanically ventilated poultry operations are an important environmental concern. Open Path Tunable Diode Laser Absorption Spectroscopy has emerged as a robust real-time method for gas phase measurement of ammonia concentrations in agricultural settings. ...

  6. Dynamic Model of an Ammonia Synthesis Reactor Based on Open Information

    OpenAIRE

    Jinasena, Asanthi; Lie, Bernt; Glemmestad, Bjørn

    2016-01-01

    Ammonia is a widely used chemical, hence the ammonia manufacturing process has become a standard case study in the scientific community. In the field of mathematical modeling of the dynamics of ammonia synthesis reactors, there is a lack of complete and well documented models. Therefore, the main aim of this work is to develop a complete and well documented mathematical model for observing the dynamic behavior of an industrial ammonia synthesis reactor system. The mode...

  7. Mechanisms of the Effects of Acidosis and Hypokalemia on Renal Ammonia Metabolism

    OpenAIRE

    Han, Ki-Hwan

    2011-01-01

    Renal ammonia metabolism is the predominant component of net acid excretion and new bicarbonate generation. Renal ammonia metabolism is regulated by acid-base balance. Both acute and chronic acid loads enhance ammonia production in the proximal tubule and secretion into the urine. In contrast, alkalosis reduces ammoniagenesis. Hypokalemia is a common electrolyte disorder that significantly increases renal ammonia production and excretion, despite causing metabolic alkalosis. Although the net ...

  8. A review of ammonia-oxidizing bacteria and archaea in Chinese soils

    OpenAIRE

    Ji-Zheng eHe; Ju-Pei eShen; Li-Mei eZhang; Hong J eDi

    2012-01-01

    Ammonia (NH3) oxidation, the first and rate-limiting step of nitrification, is a key step in the global Nitrogen (N) cycle. Major advances have been made in recent years in our knowledge and understanding of the microbial communities involved in ammonia oxidation in a wide range of habitats, including Chinese agricultural soils. In this mini-review, we focus our attention on the distribution and community diversity of ammonia-oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA) in Chi...

  9. Proximal tubule-specific glutamine synthetase deletion alters basal and acidosis-stimulated ammonia metabolism.

    Science.gov (United States)

    Lee, Hyun-Wook; Osis, Gunars; Handlogten, Mary E; Lamers, Wouter H; Chaudhry, Farrukh A; Verlander, Jill W; Weiner, I David

    2016-06-01

    Glutamine synthetase (GS) catalyzes the recycling of NH4 (+) with glutamate to form glutamine. GS is highly expressed in the renal proximal tubule (PT), suggesting ammonia recycling via GS could decrease net ammoniagenesis and thereby limit ammonia available for net acid excretion. The purpose of the present study was to determine the role of PT GS in ammonia metabolism under basal conditions and during metabolic acidosis. We generated mice with PT-specific GS deletion (PT-GS-KO) using Cre-loxP techniques. Under basal conditions, PT-GS-KO increased urinary ammonia excretion significantly. Increased ammonia excretion occurred despite decreased expression of key proteins involved in renal ammonia generation. After the induction of metabolic acidosis, the ability to increase ammonia excretion was impaired significantly by PT-GS-KO. The blunted increase in ammonia excretion occurred despite greater expression of multiple components of ammonia generation, including SN1 (Slc38a3), phosphate-dependent glutaminase, phosphoenolpyruvate carboxykinase, and Na(+)-coupled electrogenic bicarbonate cotransporter. We conclude that 1) GS-mediated ammonia recycling in the PT contributes to both basal and acidosis-stimulated ammonia metabolism and 2) adaptive changes in other proteins involved in ammonia metabolism occur in response to PT-GS-KO and cause an underestimation of the role of PT GS expression.

  10. 40 CFR 418.20 - Applicability; description of the ammonia subcategory.

    Science.gov (United States)

    2010-07-01

    ... ammonia subcategory. 418.20 Section 418.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Ammonia Subcategory § 418.20 Applicability; description of the ammonia subcategory. The provisions of this subpart...

  11. The Full-Scale Implementation of an Innovative Biological Ammonia Treatment Process

    Science.gov (United States)

    Across the United States, high levels of ammonia in drinking water sources can be found, including small communities like Palo, Iowa (approximate population of 1,026). Although ammonia in water does not pose a direct health concern, ammonia nitrification can cause a number of iss...

  12. Investigation into ammonia stress on Cyperus alternifolius and its impact on nutrient removal in microcosm experiments.

    Science.gov (United States)

    Tao, Wendong; Han, Jianqiu; Li, Hanyan

    2015-11-01

    Ammonia stress on plants has been investigated at discrete ammonia concentrations in constructed wetlands. This study introduced a Gaussian model to simulate the kinetics of ammonia stress and investigated reversible and irreversible ammonia stress on Cyperus alternifolius in wetland-like microcosms. Ammonia stress on plant weight increase and oxygen release potential started at weekly ammonia concentrations of 27 and 28 mg N/L, reached 50% inhibition at 178 and 158 mg N/L, and resulted in lethal effects at 311 and 303 mg N/L, respectively. The stress of one-time ammonia concentrations up to 400 mg N/L could be reversible. Ammonia concentrations constantly above 219 mg N/L exerted irreversible stress. In the microcosms with ammonia concentrations above the 50% inhibition levels, plants played a minor role in nitrogen removal. Nitrogen removal performance was not affected considerably by ammonia stress. Orthophosphate removal was suppressed by ammonia stress due to less plant uptake. Design and operation of constructed wetlands should consider wastewater ammonia concentration so that the integrity of constructed wetland ecosystems can be maintained.

  13. Effect of ammonia on the anaerobic hydrolysis of cellulose and tributyrin

    NARCIS (Netherlands)

    Vasconcelos Fernandes, T.; Keesman, K.J.; Zeeman, G.; Lier, van J.B.

    2012-01-01

    Ammonia nitrogen is one of the most common inhibitors in the anaerobic digestion of complex wastes containing high concentrations of ammonia like animal manures, blackwater and waste oil from gastronomy. The inhibiting effect of ammonia on methanogenesis has been well established. In contrast, the k

  14. Interorgan ammonia and amino acid metabolism in metabolically stable patients with cirrhosis and a TIPSS.

    Science.gov (United States)

    Olde Damink, Steven W M; Jalan, Rajiv; Redhead, Doris N; Hayes, Peter C; Deutz, Nicolaas E P; Soeters, Peter B

    2002-11-01

    Ammonia is central to the pathogenesis of hepatic encephalopathy. This study was designed to determine the quantitative dynamics of ammonia metabolism in patients with cirrhosis and previous treatment with a transjugular intrahepatic portosystemic stent shunt (TIPSS). We studied 24 patients with cirrhosis who underwent TIPSS portography. Blood was sampled and blood flows were measured across portal drained viscera, leg, kidney, and liver, and arteriovenous differences across the spleen and the inferior and superior mesenteric veins. The highest amount of ammonia was produced by the portal drained viscera. The kidneys also produced ammonia in amounts that equaled total hepatosplanchnic area production. Skeletal muscle removed more ammonia than the cirrhotic liver. The amount of nitrogen that was taken up by muscle in the form of ammonia was less than the glutamine that was released. The portal drained viscera consumed glutamine and produced ammonia, alanine, and citrulline. Urea was released in the splenic and superior mesenteric vein, contributing to whole-body ureagenesis in these cirrhotic patients. In conclusion, hyperammonemia in metabolically stable, overnight-fasted patients with cirrhosis of the liver and a TIPSS results from portosystemic shunting and renal ammonia production. Skeletal muscle removes more ammonia from the circulation than the cirrhotic liver. Muscle releases excessive amounts of the nontoxic nitrogen carrier glutamine, which can lead to ammonia production in the portal drained viscera (PDV) and kidneys. Urinary ammonia excretion and urea synthesis appear to be the only way to remove ammonia from the body.

  15. Identifying Potential Mechanisms Enabling Acidophily in the Ammonia-Oxidizing Archaeon “

    NARCIS (Netherlands)

    Lehtovirta-Morley, L.E.; Sayavedra-Soto, L.A.; Gallois, N.; Schouten, S.; Stein, L.Y.; Prosser, J.I.; Nicol, G.W.

    2016-01-01

    Ammonia oxidation is the first and rate-limiting step in nitrification and is dominated by two distinct groups of microorganismsin soil: ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB). AOA are often more abundant than AOBand dominate activity in acid soils. The mechanism of amm

  16. Gut does not contribute to systemic ammonia release in humans without portosystemic shunting

    NARCIS (Netherlands)

    van de Poll, Marcel C. G.; Ligthart-Melis, Gerdien C.; Damink, Steven W. M. Olde; van Leeuwen, Paul A. M.; Beets-Tan, Regina G. H.; Deutz, Nicolaas E. P.; Wigmore, Stephen J.; Soeters, Peter B.; Dejong, Cornelis H. C.

    2008-01-01

    The gut is classically seen as the main source of circulating ammonia. However, the contribution of the intestines to systemic ammonia production may be limited by hepatic extraction of portal-derived ammonia. Recent data suggest that the kidney may be more important than the gut for systemic ammoni

  17. 78 FR 52192 - Final Aquatic Life Ambient Water Quality Criteria For Ammonia-Freshwater 2013

    Science.gov (United States)

    2013-08-22

    ... AGENCY Final Aquatic Life Ambient Water Quality Criteria For Ammonia-- Freshwater 2013 AGENCY... from effects of ammonia in freshwater (EPA 822-R-13-001). The final criteria incorporate the latest scientific knowledge on the toxicity of ammonia to freshwater aquatic life. On December 30, 2009,...

  18. Formaldoxime hydrogen bonded complexes with ammonia and hydrogen chloride

    Science.gov (United States)

    Golec, Barbara; Mucha, Małgorzata; Sałdyka, Magdalena; Barnes, Austin; Mielke, Zofia

    2015-02-01

    An infrared spectroscopic and MP2/6-311++G(2d,2p) study of hydrogen bonded complexes of formaldoxime with ammonia and hydrogen chloride trapped in solid argon matrices is reported. Both 1:1 and 1:2 complexes between formaldoxime and ammonia, hydrogen chloride have been identified in the CH2NOH/NH3/Ar, CH2NOH/HCl/Ar matrices, respectively, their structures were determined by comparison of the spectra with the results of calculations. In the 1:1 complexes present in the argon matrices the OH group of formaldoxime acts as a proton donor for ammonia and the nitrogen atom acts as a proton acceptor for hydrogen chloride. In the 1:2 complexes ammonia or hydrogen chloride dimers interact both with the OH group and the nitrogen atom of CH2NOH to form seven membered cyclic structures stabilized by three hydrogen bonds. The theoretical spectra generally agree well with the experimental ones, but they seriously underestimate the shift of the OH stretch for the 1:1 CH2NOH⋯NH3 complex.

  19. Nitrate to ammonia ceramic (NAC) bench scale stabilization study

    Energy Technology Data Exchange (ETDEWEB)

    Caime, W.J.; Hoeffner, S.L. [RUST - Clemson Technical Center, Anderson, SC (United States)

    1995-10-01

    Department of Energy (DOE) sites such as the Hanford site, Idaho National Engineering Laboratory (INEL), Savannah River site, Oak Ridge National Laboratory (ORNL) have large quantities of sodium-nitrate based liquid wastes. A process to reduce the nitrates to ammonia has been developed at ORNL. This technology creates a sludge lower in nitrates. This report describes stabilization possibilities of the sludge.

  20. Ammonia removal from leachate solution using natural Chinese clinoptilolite.

    Science.gov (United States)

    Wang, Yuqiu; Liu, Shijun; Xu, Ze; Han, Tianwei; Chuan, Sun; Zhu, Tan

    2006-08-25

    This paper assesses the potential of natural Chinese clinoptilolite for ammonia removal from the leachate solution of sewage sludge. In batch study the effects of relevant parameters, such as contact time, initial ammonia concentration and particle size of clinoptilolite, were examined respectively. The results show that the data obtained from batch studies were fit to Langmuir and Freundlich isotherms and the Langmuir isotherms reflect more reasonable for ammonium ion uptake onto clinoptilolite; the clinoptilolite adsorption process has been proved effective, at laboratory scale, the maximum adsorption capacity of the clinoptilolite, for ammonium concentration ranging from 11.12 to 115.16 mg NH(4)-N L(-1) in leachate solution, was about 1.74 mg NH(4)-Ng(-1); the time to adsorption equilibrium was 2.5 h in leachate solution and 1.5 h more than for in NH(4)Cl synthetic solution; ammonium adsorption increased with decreasing clinoptilolite particle size; the ammonia removal capacity of clinoptilolite increased with increasing initial ammonia concentration. It is believed that as adsorption agent for NH(4)-N removal from sludge leachate, natural Chinese clinoptilolite can be feasible.

  1. REGENERATION OF AMMONIA SOLUTION FOR CO2 CAPTURE IN POSTCOMBUSTION

    Directory of Open Access Journals (Sweden)

    CAROL TORO

    2014-01-01

    Full Text Available This study investigated enthalpy of solutions and solubility for a NH3/CO2 system. Measurements were performed in a thermoregulated Lewis-type cell reactor, temperatures ranging from 278 to 303 K and mass concentrations from 2 wt% to 5 wt%. Enthalpies of solution of CO2 and solubility have been obtained as function of loading, α (moles CO2/mol NH3. Results show that ammonia solutions concentrations of 3 and 5 wt% promote the formation of ammonium bicarbonate. Beside, ammonia concentration of 2 wt% promotes the formation of ammonium carbonate. Therefore, to use ammonia concentrations of 3 and 5 wt% need less energy that a concentration of 2 wt% to reverse the reaction. Regeneration system was simulated using Aspen plus™ software for a pulverised coal fired power plant (CF in a post-combustion process. Model analysis established that NH3 heat duty is lower than MEA and MDEA ones. The energy consumption reaches 2.83 GJ•t-1 CO2. Regarding heat duty and ammonia losses, 3 wt% NH3 is the suitable concentration to capture CO2.

  2. Predicting catalysis: understanding ammonia synthesis from first-principles calculations.

    Science.gov (United States)

    Hellman, A; Baerends, E J; Biczysko, M; Bligaard, T; Christensen, C H; Clary, D C; Dahl, S; van Harrevelt, R; Honkala, K; Jonsson, H; Kroes, G J; Luppi, M; Manthe, U; Nørskov, J K; Olsen, R A; Rossmeisl, J; Skúlason, E; Tautermann, C S; Varandas, A J C; Vincent, J K

    2006-09-14

    Here, we give a full account of a large collaborative effort toward an atomic-scale understanding of modern industrial ammonia production over ruthenium catalysts. We show that overall rates of ammonia production can be determined by applying various levels of theory (including transition state theory with or without tunneling corrections, and quantum dynamics) to a range of relevant elementary reaction steps, such as N(2) dissociation, H(2) dissociation, and hydrogenation of the intermediate reactants. A complete kinetic model based on the most relevant elementary steps can be established for any given point along an industrial reactor, and the kinetic results can be integrated over the catalyst bed to determine the industrial reactor yield. We find that, given the present uncertainties, the rate of ammonia production is well-determined directly from our atomic-scale calculations. Furthermore, our studies provide new insight into several related fields, for instance, gas-phase and electrochemical ammonia synthesis. The success of predicting the outcome of a catalytic reaction from first-principles calculations supports our point of view that, in the future, theory will be a fully integrated tool in the search for the next generation of catalysts.

  3. Ammonia as a component of fruit fly attractants.

    Science.gov (United States)

    Abstract Fruit flies in the genus Anastrepha, especially the reproductive age females, are attracted to protein baits. Synthetic lures based on the principal components of protein degradation, especially ammonia along with acetic acid, were tested against three of the most economically important Ana...

  4. Ammonia Formulations and Capture of Anastrepha Fruit Flies (Diptera: Tephritidae)

    Science.gov (United States)

    Fruit flies in the genus Anastrepha, especially the reproductive age females, are attracted in numbers to protein baits. Synthetic lures based on the principle components of protein degradation, especially ammonia along with acetic acid, were tested against three of the most economically important ...

  5. IRIS Toxicological Review of Ammonia (Interagency Science Consultation Draft)

    Science.gov (United States)

    On June 1, 2012, the draft Toxicological Review of Ammonia and the draft charge to external peer reviewers were released for external peer review and public comment. The Toxicological Review and charge were reviewed internally by EPA and by other federal agencies and White House ...

  6. IRIS Toxicological Review of Ammonia (Revised External Review Draft)

    Science.gov (United States)

    In August 2013, EPA submitted a revised draft IRIS assessment of ammonia to the agency's Science Advisory Board (SAB) and posted this draft on the IRIS website. EPA had previously released a draft of the assessment for public comment, held a public meeting about the draft, and ...

  7. RAMPS: The Radio Ammonia Mid-Plane Survey

    Science.gov (United States)

    Jackson, James M.; Hogge, Taylor; Stephens, Ian; Whitaker, John Scott

    2016-01-01

    The Radio Ammonia Mid-Plane Survey (RAMPS) is a new 1.3 cm survey of the Galactic plane that will simultaneously image several 23 GHz ammonia lines [NH3 (1,1), (2,2), (3,3), (4,4), and (5,5)] and the 22.2 GHz water maser line from l = 10o to 40o and b = -0.5o to 0.5o. RAMPS employs the K-band Focal Plane Array receiver on the NRAO Green Bank Telescope. The main goal of RAMPS is to characterize the Galactic population of dense star-forming molecular clumps by measuring the gas temperatures, column densities, radial velocities, and kinematic distances using the ammonia line ratios. I report results from the survey's first 6.4 square degrees and present large-scale NH3 (1,1), (2,2), and (3,3) integrated intensity maps, gas temperature maps, and column density maps. To date over 500 clumps have been identified and characterized. In addition, RAMPS has now detected 619 water maser sites, most of which are detected for the first time. Only 60% of the water masers are associated with detected ammonia emission. We have also discovered a remarkable star forming region with unusually broad NH3 lines (ΔV ~ 25 km/s) and a very rare NH3 (3,3) shock-excited maser. Altough located in the Galactic disk, this clump has characteristics usually found in Galactic Center clouds.

  8. Detection of Widespread Hot Ammonia in the Galactic Center

    CERN Document Server

    Mills, Elisabeth A C

    2013-01-01

    We present the detection of metastable inversion lines of ammonia from energy levels high above the ground state. We detect these lines in both emission and absorption toward fifteen of seventeen positions in the central 300 parsecs of the Galaxy. In total, we observe seven metastable transitions of ammonia: (8,8), (9,9), (10,10), (11,11), (12,12), (13,13) and (15,15), with energies (in Kelvins) ranging from 680 to 2200 K. We also map emission from ammonia (8,8) and (9,9) in two clouds in the Sgr A complex (M-0.02-0.07 and M-0.13-0.08), and we find that the line emission is concentrated toward the the dense centers of these molecular clouds. The rotational temperatures derived from the metastable lines toward M-0.02-0.07 and M-0.13-0.08 and an additional cloud (M0.25+0.01) range from 350 to 450 K. Similarly highly-excited lines of ammonia have previously been observed toward Sgr B2, where gas with kinetic temperatures of ~600 K has been inferred. Our observations show that the existence of a hot molecular gas...

  9. Measurement of ambient ammonia with diffusion tube samplers

    NARCIS (Netherlands)

    Thijsse, T.R.; Duyzer, J.H.; Verhagen, H.L.M.; Wyers, G.P.; Wayers, A.; Möls, J.J.

    1998-01-01

    Results of a study to evaluate the suitability of passive samplers for the measurement of monthly averaged ammonia concentrations are presented. Five different samplers were tested. Four were diffusion tube samplers which differed in length and in the way they were modified to minimize disturbing ef

  10. Litter ammonia losses amplified by higher air flow rates

    Science.gov (United States)

    ABSTRACT Broiler litter utilization has largely been associated with land application as fertilizer. Reducing ammonia (NH3) released from litter enhances its fertilizer value and negates detrimental impacts to the environment. A laboratory study was conducted to quantify the effect of air flow var...

  11. 46 CFR 151.50-32 - Ammonia, anhydrous.

    Science.gov (United States)

    2010-10-01

    ... copper bearing alloys shall not be used as materials of construction for tanks, pipelines, valves... have close at hand at all times a canister mask approved for ammonia or each person shall carry on his... provide respiratory protection for emergency escape from a contaminated area resulting from cargo...

  12. Assessing the reliability of calculated catalytic ammonia synthesis rates

    DEFF Research Database (Denmark)

    Medford, Andrew James; Wellendorff, Jess; Vojvodic, Aleksandra

    2014-01-01

    We introduce a general method for estimating the uncertainty in calculated materials properties based on density functional theory calculations. We illustrate the approach for a calculation of the catalytic rate of ammonia synthesis over a range of transition-metal catalysts. The correlation...

  13. Catalytic synthesis of ammonia using vibrationally excited nitrogen molecules

    DEFF Research Database (Denmark)

    Hansen, Flemming Yssing; Henriksen, Niels Engholm; Billing, Gert D.

    1992-01-01

    The dissociation of nitrogen is the rate-limiting step in the catalytic synthesis of ammonia. Theoretical calculations have shown that the dissociative sticking probability of molecular nitrogen on catalytic active metal surfaces is enhanced by orders of magnitude when the molecules...

  14. Insights into the ammonia synthesis from first-principles

    DEFF Research Database (Denmark)

    Hellmann, A.; Honkala, Johanna Karoliina; Remediakis, Ioannis

    2006-01-01

    A new set of measurements is used to further test a recently published first-principles model for the ammonia (NH3) synthesis on an unpromoted Ru-based catalyst. A direct comparison shows an overall good agreement in NH3 productivity between the model and the experiment. In addition, macro...

  15. Priming ammonia lyases and aminomutases for industrial and therapeutic applications

    NARCIS (Netherlands)

    Heberling, Matthew M.; Wu, Bian; Bartsch, Sebastian; Janssen, Dick B.

    2013-01-01

    Ammonia lyases (AL) and aminomutases (AM) are emerging in green synthetic routes to chiral amines and an AL is being explored as an enzyme therapeutic for treating phenylketonuria and cancer. Although the restricted substrate range of the wild-type enzymes limits their widespread application, the no

  16. Accelerated DFT-Based Design of Materials for Ammonia Storage

    DEFF Research Database (Denmark)

    Jensen, Peter Bjerre; Bialy, Agata; Blanchard, Didier

    2015-01-01

    Future energy carriers are needed in order to lower the CO2 emissions resulting from the burning of fossil fuels. One possible energy carrier is ammonia, which can be stored safely and reversibly in metal halide ammines; however, the release often occurs in multiple steps at too high temperatures...... materials is the first known high-capacity ternary metal halide ammine, which we have subsequently synthesized and confirmed the ammonia storage properties using temperature-programmed desorption (TPD).......Future energy carriers are needed in order to lower the CO2 emissions resulting from the burning of fossil fuels. One possible energy carrier is ammonia, which can be stored safely and reversibly in metal halide ammines; however, the release often occurs in multiple steps at too high temperatures....... Therefore, there is a need for new materials, releasing the ammonia in a narrow temperature interval. To search for new mixed metal halide chlorides, we use DFT calculations guided by a genetic algorithm (GA) to expedite the search, as the defined search space allowing up to three different metals contains...

  17. Shannon Entropy of Ammonia Volatilization from Fertilized Agricultural Soils

    Science.gov (United States)

    The economic loss of ammonia (NH3) volatilization from chemical N fertilizers applied to farmlands worldwide is 11.6 billion US dollars per year. The economic impact of negative environmental effects resulted from NH3 volatilization, i.e., formation of potent greenhouse gas (N2O) and PM2.5, is diffi...

  18. Equations of State and Phase Diagrams of Ammonia

    Science.gov (United States)

    Glasser, Leslie

    2009-01-01

    We present equations of state relating the phases and a three-dimensional phase diagram for ammonia with its solid, liquid, and vapor phases, based on fitted authentic experimental data and including recent information on the high-pressure solid phases. This presentation follows similar articles on carbon dioxide and water published in this…

  19. Redesign of a Phenylalanine Aminomutase into a Phenylalanine Ammonia Lyase

    NARCIS (Netherlands)

    Bartsch, S.; Wybenga, G.G.; Jansen, M.; Heberling, M.M.; Wu, B.; Dijkstra, B.W.; Janssen, D.B.

    2013-01-01

    An aminomutase, naturally catalyzing the interconversion of (S)--phenylalanine and (R)--phenylalanine, was converted into an ammonia lyase catalyzing the nonoxidative deamination of phenylalanine to cinnamic acid by a rational single-point mutation. It could be shown by crystal structures and kineti

  20. Macroecological patterns of archaeal ammonia oxidizers in the Atlantic Ocean

    NARCIS (Netherlands)

    Sintes, E.; Ouillon, N.; Herndl, G.J.

    2015-01-01

    Macroecological patterns are found in animals and plants, but also in micro-organisms.Macroecological and biogeographic distribution patterns in marine Archaea, however,have not been studied yet. Ammonia-oxidizing Archaea (AOA) show a bipolar distribution(i.e. similar communities in the northernmost

  1. Inhibition of bacterial ammonia oxidation by organohydrazines in soil microcosms

    Directory of Open Access Journals (Sweden)

    Yucheng eWu

    2012-01-01

    Full Text Available Hydroxylamine oxidation by hydroxylamine oxidoreductase (HAO is a key step for energy-yielding in support of the growth of ammonia-oxidizing bacteria (AOB. Organohydrazines have been shown to inactivate HAO from Nitrosomonas europaea, and may serve as selective inhibitors to differentiate bacterial from archaeal ammonia oxidation due to the absence of bacterial HAO gene homologue in known ammonia-oxidizing archaea (AOA. In this study, the effects of three organohydrazines on activity, abundance and composition of AOB and AOA were evaluated in soil microcosms. The results indicate that phenylhydrazine and methylhydrazine at the concentration of 100 mol per gram dry weight soil completely suppressed the activity of soil nitrification. DGGE fingerprinting and sequencing analysis of bacterial ammonia monooxygenase subunit A gene (amoA clearly demonstrated that nitrification activity change is well paralleled with the growth of Nitrosomonas europaea-like AOB in soil microcosms. No significant correlation between AOA community structure and nitrification activity was observed among all treatments during the incubation period, although incomplete inhibition of nitrification activity occurred in 2-hydroxyethylhydrazine-amended soil microcosms. These findings show that the HAO-targeted organohydrazines can effectively inhibit bacterial nitrification in soil, and the mechanism of organohydrazine affecting AOA remains unclear.

  2. Diversity, physiology, and niche differentiation of ammonia-oxidizing archaea.

    Science.gov (United States)

    Hatzenpichler, Roland

    2012-11-01

    Nitrification, the aerobic oxidation of ammonia to nitrate via nitrite, has been suggested to have been a central part of the global biogeochemical nitrogen cycle since the oxygenation of Earth. The cultivation of several ammonia-oxidizing archaea (AOA) as well as the discovery that archaeal ammonia monooxygenase (amo)-like gene sequences are nearly ubiquitously distributed in the environment and outnumber their bacterial counterparts in many habitats fundamentally revised our understanding of nitrification. Surprising insights into the physiological distinctiveness of AOA are mirrored by the recognition of the phylogenetic uniqueness of these microbes, which fall within a novel archaeal phylum now known as Thaumarchaeota. The relative importance of AOA in nitrification, compared to ammonia-oxidizing bacteria (AOB), is still under debate. This minireview provides a synopsis of our current knowledge of the diversity and physiology of AOA, the factors controlling their ecology, and their role in carbon cycling as well as their potential involvement in the production of the greenhouse gas nitrous oxide. It emphasizes the importance of activity-based analyses in AOA studies and formulates priorities for future research.

  3. Engineering Tests of Experimental Ammonia Process Printer-Developer

    Science.gov (United States)

    1950-07-06

    up for an experimental am:tmoa process printer- developer to meet the military characteristics. Thlis machine was Krocurod under development contract ...over the top of the can. A small light on the front panel of the mucl -ine indicates when the level of the ammonia in the storage tank is such that

  4. Low-liquid pretreatment of corn stover with aqueous ammonia.

    Science.gov (United States)

    Li, Xuan; Kim, Tae Hyun

    2011-04-01

    A low-liquid pretreatment method of corn stover using aqueous ammonia was studied to reduce the severity and liquid throughput associated with the pretreatment step for ethanol production. Corn stover was treated at 0.5-50.0 wt.% of ammonia loading, 1:0.2-5.0 (w/w) of solid-to-liquid ratio, 30 °C for 4-12 weeks. The effects of these conditions on the composition and enzyme digestibility of pretreated corn stover were investigated. Pretreatment of corn stover at 30°C for four weeks using 50 wt.% of ammonia loading and 1:5 solid-to-liquid ratio resulted in 55% delignification and 86.5% glucan digestibility with 15 FPU cellulase+30 CBU β-glucosidase/g-glucan. Simultaneous saccharification and fermentation of corn stover treated at 30 °C for four weeks using 50 wt.% ammonia loading and 1:2 solid-to-liquid ratio gave an ethanol yield of 73% of the theoretical maximum based on total carbohydrates (glucan+xylan) present in the untreated material.

  5. Ammonia emissions from cattle urine and dung excreted on pasture

    DEFF Research Database (Denmark)

    Laubach, J; Taghizadeh-Toosi, Arezoo; Gibbs, S J;

    2013-01-01

    Twelve cattle were kept for three days in a circular area of 16 m radius on short pasture and fed with freshly-cut pasture. Ammonia (NH3) emissions from the urine and dung excreted by the cattle were measured with a micrometeorological mass-balance method, during the cattle presence and for 10 su...

  6. A comparative kinetic study of SNCR process using ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Javed, M. Tayyeb; Ahmed, Z.; Ibrahim, M. Asim; Irfan, N.

    2008-07-01

    The paper presents comparative kinetic modelling of nitrogen oxides (NOx) removal from flue gases by selective non-catalytic reduction process using ammonia as reducing agent. The computer code SENKIN is used in this study with the three published chemical kinetic mechanisms; Zanoelo, Kilpinen and Skreiberg. Kinetic modeling was performed for an isothermal plug flow reactor at atmospheric pressure so as to compare it with the experimental results. A 500 ppm NOx background in the flue gas is considered and kept constant throughout the investigation. The ammonia performance was modeled in the range of 750 to 1250{sup o}C using the molar ratios NH{sub 3}/NOx from 0.25 to 3.0 and residence times up to 1.5 seconds. The modeling using all the mechanisms exhibits and confirms a temperature window of NOx reduction with ammonia. It was observed that 80% of NOx reduction efficiency could be achieved if the flue gas is given 300 msec to react with ammonia, while it is passing through a section within a temperature range of 910 to 1060{sup o}C (Kilpinen mechanism) or within a temperature range of 925 to 1030{sup o}C (Zanoelo mechanism) or within a temperature range of 890 to 1090{sup o}C (Skreiberg mechanism). 20 refs., 6 figs.

  7. Ammonia chemistry in oxy-fuel combustion of methane

    DEFF Research Database (Denmark)

    Mendiara, Teresa; Glarborg, Peter

    2009-01-01

    concentrations and alteration in the amount and partitioning of O/H radicals, rather than direct reactions between N-radicals and CO2, are responsible for the effect of a high CO2 concentration on ammonia conversion. When CO2 is present as a bulk gas, formation of NO is facilitated by the increased OH/H ratio...

  8. System Modeling for Ammonia Synthesis Energy Recovery System

    Science.gov (United States)

    Bran Anleu, Gabriela; Kavehpour, Pirouz; Lavine, Adrienne; Ammonia thermochemical Energy Storage Team

    2015-11-01

    An ammonia thermochemical energy storage system is an alternative solution to the state-of-the-art molten salt TES system for concentrating solar power. Some of the advantages of this emerging technology include its high energy density, no heat losses during the storage duration, and the possibility of long storage periods. Solar energy powers an endothermic reaction to disassociate ammonia into hydrogen and nitrogen, which can be stored for future use. The reverse reaction is carried out in the energy recovery process; a hydrogen-nitrogen mixture flowing through a catalyst bed undergoes the exothermic ammonia synthesis reaction. The goal is to use the ammonia synthesis reaction to heat supercritical steam to temperatures on the order of 650°C as required for a supercritical steam Rankine cycle. The steam will flow through channels in a combined reactor-heat exchanger. A numerical model has been developed to determine the optimal design to heat supercritical steam while maintaining a stable exothermic reaction. The model consists of a transient one dimensional concentric tube counter-flow reactor-heat exchanger. The numerical model determines the inlet mixture conditions needed to achieve various steam outlet conditions.

  9. Assimilating Remote Ammonia Observations with a Refined Aerosol Thermodynamics Adjoint"

    Science.gov (United States)

    Ammonia emissions parameters in North America can be refined in order to improve the evaluation of modeled concentrations against observations. Here, we seek to do so by developing and applying the GEOS-Chem adjoint nested over North America to conductassimilation of observations...

  10. Quantum simulations of the hydrogen molecule on ammonia clusters

    Science.gov (United States)

    Mella, Massimo; Curotto, E.

    2013-09-01

    Mixed ammonia-hydrogen molecule clusters [H2-(NH3)n] have been studied with the aim of exploring the quantitative importance of the H2 quantum motion in defining their structure and energetics. Minimum energy structures have been obtained employing genetic algorithm-based optimization methods in conjunction with accurate pair potentials for NH3-NH3 and H2-NH3. These include both a full 5D potential and a spherically averaged reduced surface mimicking the presence of a para-H2. All the putative global minima for n ⩾ 7 are characterized by H2 being adsorbed onto a rhomboidal ammonia tetramer motif formed by two double donor and two double acceptor ammonia molecules. In a few cases, the choice of specific rhombus seems to be directed by the vicinity of an ammonia ad-molecule. Diffusion Monte Carlo simulations on a subset of the species obtained highlighted important quantum effects in defining the H2 surface distribution, often resulting in populating rhomboidal sites different from the global minimum one, and showing a compelling correlation between local geometrical features and the relative stability of surface H2. Clathrate-like species have also been studied and suggested to be metastable over a broad range of conditions if formed.

  11. Ammonia sensor for closed-loop SCR control

    NARCIS (Netherlands)

    Wang, D.Y.; Yao, S.; Shost, M.; Yoo, J.H.; Cabush, D.; Racine, D.; Cloudt, R.P.M.; Willems, F.P.T.

    2009-01-01

    Selective Catalytic Reduction (SCR) is the dominant solution for meeting future NOx reduction regulations for heavy-duty diesel powertrains. SCR systems benefit from closed-loop control if an appropriate exhaust gas sensor were available. An ammonia sensor has recently been developed for use as a fe

  12. 21 CFR 862.1065 - Ammonia test system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ammonia test system. 862.1065 Section 862.1065 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems §...

  13. Does formate reduce alpha-ketoglutarate and ammonia to glutamate?

    Science.gov (United States)

    Maughan, Q.; Miller, S. L.; Bada, J. L. (Principal Investigator)

    1999-01-01

    The reported reduction of alpha-ketoglutarate and ammonia by formate is much slower than described (Morowitz et al., 1995). The formate reduction if any is small under these conditions. Glutamate is produced from a reduction by a second molecule of alpha-ketoglutarate involving an oxidative decarboxylation.

  14. Corrosion protection of steel in ammonia/water heat pumps

    Science.gov (United States)

    Mansfeld, Florian B.; Sun, Zhaoli

    2003-10-14

    Corrosion of steel surfaces in a heat pump is inhibited by adding a rare earth metal salt to the heat pump's ammonia/water working fluid. In preferred embodiments, the rare earth metal salt includes cerium, and the steel surfaces are cerated to enhance the corrosion-inhibiting effects.

  15. Anaerobic digestion of swine manure: Inhibition by ammonia

    DEFF Research Database (Denmark)

    Hansen, Kaare Hvid; Angelidaki, Irini; Ahring, Birgitte Kiær

    1998-01-01

    A stable anaerobic degradation of swine manure with ammonia concentration of 6 g-N/litre was obtained in continuously stirred tank reactors with a hydraulic retention time of 15 days, at Four different temperatures. Methane yields of 188, 141, 67 and 22 ml-CH4/g-VS were obtained at 37, 45, 55...

  16. A high-sensitivity chemical sensor based on titania coated optical-fiber long period grating for ammonia sensing in water

    Science.gov (United States)

    Tiwari, D.; James, S. W.; Tatam, R. P.; Korposh, S.; Lee, S. W.

    2015-07-01

    Two highly sensitive ammonia sensors, formed by depositing coatings composed of titanium dioxide (TiO2) onto the cladding of an optical fibre sensing platform, are evaluated. A long period grating (LPG) of period 111 μm was fabricated in the core of an optical fibre so that the LPG operates at or near the phase matching turning point (PMTP). The first coating that was investigated was composed of TiO2 nanoparticles deposited by liquid phase deposition. The sensor showed high sensitivity and allowed low concentrations of ammonia in water (0.01 ppm) to be detected with a response time of less than 60 sec. The second coating was composed of TiO2 with subsequent layers of poly (allyamine hydrochloride) (PAH), and SiO2 nanospheres infused with a sensitive element composed of porphine. The ammonia adsorption to the porphine compound led to the changes in the LPG's transmission spectrum and allowed 0.1 ppm of ammonia in water to be detected with a response time of less than 60 sec.

  17. Study on adsorption and desorption of ammonia on graphene

    Science.gov (United States)

    Zhang, Zhengwei; Zhang, Xinfang; Luo, Wei; Yang, Hang; He, Yanlan; Liu, Yixing; Zhang, Xueao; Peng, Gang

    2015-09-01

    The gas sensor based on pristine graphene with conductance type was studied theoretically and experimentally. The time response of conductance measurements showed a quickly and largely increased conductivity when the sensor was exposed to ammonia gas produced by a bubble system of ammonia water. However, the desorption process in vacuum took more than 1 h which indicated that there was a larger number of transferred carriers and a strong adsorption force between ammonia and graphene. The desorption time could be greatly shortened down to about 2 min by adding the flow of water-vapor-enriched air at the beginning of the recovery stage which had been confirmed as a rapid and high-efficiency desorption process. Moreover, the optimum geometries, adsorption energies, and the charge transfer number of the composite systems were studied with first-principle calculations. However, the theoretical results showed that the adsorption energy between NH3 and graphene was too small to fit for the experimental phenomenon, and there were few charges transferred between graphene and NH3 molecules, which was completely different from the experiment measurement. The adsorption energy between NH4 and graphene increased stage by stage which showed NH4 was a strong donor. The calculation suggested that H2O molecule could help a quick desorption of NH4 from graphene by converting NH4 to NH3 or (NH3)n(H2O)m groups, which was consistent with the experimental results. This study demonstrates that the ammonia gas produced by a bubble system of ammonia water is mainly ammonium groups of NH3 and NH4, and the NH4 moleculars are ideal candidates for the molecular doping of graphene while the interaction between graphene and the NH3 moleculars is weak.

  18. Glutamine versus ammonia utilization in the NAD synthetase family.

    Directory of Open Access Journals (Sweden)

    Jessica De Ingeniis

    Full Text Available NAD is a ubiquitous and essential metabolic redox cofactor which also functions as a substrate in certain regulatory pathways. The last step of NAD synthesis is the ATP-dependent amidation of deamido-NAD by NAD synthetase (NADS. Members of the NADS family are present in nearly all species across the three kingdoms of Life. In eukaryotic NADS, the core synthetase domain is fused with a nitrilase-like glutaminase domain supplying ammonia for the reaction. This two-domain NADS arrangement enabling the utilization of glutamine as nitrogen donor is also present in various bacterial lineages. However, many other bacterial members of NADS family do not contain a glutaminase domain, and they can utilize only ammonia (but not glutamine in vitro. A single-domain NADS is also characteristic for nearly all Archaea, and its dependence on ammonia was demonstrated here for the representative enzyme from Methanocaldococcus jannaschi. However, a question about the actual in vivo nitrogen donor for single-domain members of the NADS family remained open: Is it glutamine hydrolyzed by a committed (but yet unknown glutaminase subunit, as in most ATP-dependent amidotransferases, or free ammonia as in glutamine synthetase? Here we addressed this dilemma by combining evolutionary analysis of the NADS family with experimental characterization of two representative bacterial systems: a two-subunit NADS from Thermus thermophilus and a single-domain NADS from Salmonella typhimurium providing evidence that ammonia (and not glutamine is the physiological substrate of a typical single-domain NADS. The latter represents the most likely ancestral form of NADS. The ability to utilize glutamine appears to have evolved via recruitment of a glutaminase subunit followed by domain fusion in an early branch of Bacteria. Further evolution of the NADS family included lineage-specific loss of one of the two alternative forms and horizontal gene transfer events. Lastly, we identified NADS

  19. Studies on Ammonia Spectral Signatures Relevant to Jupiter's Clouds

    Science.gov (United States)

    Oza, A. U.; Marschall, J.; Wong, M. H.; Kalogerakis, K. S.

    2006-12-01

    Observational evidence and thermochemical models indicate an abundance of ammonia ice clouds in Jupiter's atmosphere. However, spectrally identifiable ammonia ice clouds are found covering less than 1% of Jupiter's atmosphere, notably in turbulent areas [1,2]. Current literature suggests two possible explanations: coating by a hydrocarbon haze and/or photochemical processing ("tanning")[2,3]. We are pursuing a research program investigating the above hypotheses. In the experiments, thin films of ammonia ices are deposited in a cryogenic apparatus, coated with hydrocarbons, and characterized by infrared spectroscopy. The ice films can be irradiated by ultraviolet light to study their photochemistry. The spectroscopic measurements aim to identify the processes that control the optical properties of the ice mixtures and quantify their dependence on the identity of the coating, the temperature, and the ice composition. We have observed a consistent suppression of the ammonia absorption feature at 3 μm with coverage by thin layers of hydrocarbons. Modeling calculations of the multi-layer thin films assist in the interpretation of the experimental results and reveal the role of optical interference in masking the aforementioned ammonia spectral feature. The implications of these results for Jupiter's atmosphere will be discussed. Funding from the NSF Planetary Astronomy Program under grant AST-0206270 and from the NASA Outer Planets Research Program under grant NNG06GF37G is gratefully acknowledged. The participation of Anand Oza (Princeton University) was made possible by the NSF Research Experiences for Undergraduates Program under grant PHY-0353745. 1. S. K. Atreya, A.-S. Wong, K. H. Baines, M. H. Wong, T. C. Owen, Planet. Space Science 53, 498 (2005). 2. K. H. Baines, R. W. Carlson, and L. W. Kamp, Icarus 159, 74 (2002). 3. A.-S. Wong, Y. L. Yung, and A. J. Friedson, Geophys. Res. Lett. 30, 1447 (2003).

  20. Study on adsorption and desorption of ammonia on graphene.

    Science.gov (United States)

    Zhang, Zhengwei; Zhang, Xinfang; Luo, Wei; Yang, Hang; He, Yanlan; Liu, Yixing; Zhang, Xueao; Peng, Gang

    2015-12-01

    The gas sensor based on pristine graphene with conductance type was studied theoretically and experimentally. The time response of conductance measurements showed a quickly and largely increased conductivity when the sensor was exposed to ammonia gas produced by a bubble system of ammonia water. However, the desorption process in vacuum took more than 1 h which indicated that there was a larger number of transferred carriers and a strong adsorption force between ammonia and graphene. The desorption time could be greatly shortened down to about 2 min by adding the flow of water-vapor-enriched air at the beginning of the recovery stage which had been confirmed as a rapid and high-efficiency desorption process. Moreover, the optimum geometries, adsorption energies, and the charge transfer number of the composite systems were studied with first-principle calculations. However, the theoretical results showed that the adsorption energy between NH3 and graphene was too small to fit for the experimental phenomenon, and there were few charges transferred between graphene and NH3 molecules, which was completely different from the experiment measurement. The adsorption energy between NH4 and graphene increased stage by stage which showed NH4 was a strong donor. The calculation suggested that H2O molecule could help a quick desorption of NH4 from graphene by converting NH4 to NH3 or (NH3)n(H2O)m groups, which was consistent with the experimental results. This study demonstrates that the ammonia gas produced by a bubble system of ammonia water is mainly ammonium groups of NH3 and NH4, and the NH4 moleculars are ideal candidates for the molecular doping of graphene while the interaction between graphene and the NH3 moleculars is weak.

  1. Sustainable Ammonia Synthesis – Exploring the scientific challenges associated with discovering alternative, sustainable processes for ammonia production

    Energy Technology Data Exchange (ETDEWEB)

    Nørskov, Jens [Stanford Univ., CA (United States); ; SLAC National Accelerator Lab., Menlo Park, CA (United States); Chen, Jingguang [Columbia Univ., New York, NY (United States); Brookhaven National Lab. (BNL), Upton, NY (United States); Miranda, Raul [Dept. of Energy (DOE), Washington DC (United States). Office of Science; Fitzsimmons, Tim [Dept. of Energy (DOE), Washington DC (United States). Office of Science; Stack, Robert [Dept. of Energy (DOE), Washington DC (United States). Office of Science

    2016-02-18

    Ammonia (NH3) is essential to all life on our planet. Until about 100 years ago, NH3 produced by reduction of dinitrogen (N2) in air came almost exclusively from bacteria containing the enzyme nitrogenase.. DOE convened a roundtable of experts on February 18, 2016. Participants in the Roundtable discussions concluded that the scientific basis for sustainable processes for ammonia synthesis is currently lacking, and it needs to be enhanced substantially before it can form the foundation for alternative processes. The Roundtable Panel identified an overarching grand challenge and several additional scientific grand challenges and research opportunities: -Discovery of active, selective, scalable, long-lived catalysts for sustainable ammonia synthesis. -Development of relatively low pressure (<10 atm) and relatively low temperature (<200 C) thermal processes. -Integration of knowledge from nature (enzyme catalysis), molecular/homogeneous and heterogeneous catalysis. -Development of electrochemical and photochemical routes for N2 reduction based on proton and electron transfer -Development of biochemical routes to N2 reduction -Development of chemical looping (solar thermochemical) approaches -Identification of descriptors of catalytic activity using a combination of theory and experiments -Characterization of surface adsorbates and catalyst structures (chemical, physical and electronic) under conditions relevant to ammonia synthesis.

  2. A study on ammonia removal properties using clinoptilolite Part 1 : characterization of clinoptilolite and ammonia removal properties in batch reactor

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Jeong Min; Chung, Jong Shik [Dept. of Chemical Engineering/School of Environment Engineering, Pohang University of Science and Technology, Pohang (Korea); Sun, De Shi [Dept. of Applied Chemistry, Harbin Institute of Techonology (China)

    2000-04-01

    A natural zeolite, deposit located at Guryongpo, Young-il bay, was found to be clinoptilolite containing impurities of heulandite and mordenite. Cation exchange capacity(CEC) for ammonia was about 1.41 meq/g from Na{sup +}-form of the zeolite. In batch experiment, removal efficiency of ammonia was increased as particle size of zeolite and initial concentration of Na{sup +} were decreased and SR(Stoichiometric Ratio), time, and initial concentration of ammonia increased. More than 70% aluminum ion could be removed from water having 3 ppm ammonia and 0.7 ppm Al{sup 3+} by the batch adsorption(ion exchange) experiment. Regeneration of used zeolite with NaCl solution of pH=12 has shown more than 95% of regeneration efficiency when SR'(ratio of the amount of NaCl solution employed actually to the amount in a stoichiometric quantity) was equal to 2.0. 19 refs., 10 figs., 1 tab.

  3. Ammonium recruitment and ammonia transport by E. coli ammonia channel AmtB

    DEFF Research Database (Denmark)

    Nygaard, Thomas Pedersen; Rovira, C.; Peters, Günther H.j.

    2006-01-01

    To investigate substrate recruitment and transport across the Escherichia coli Ammonia transporter B (AmtB) protein, we performed molecular dynamics simulations of the AmtB trimer. We have identified residues important in recruitment of ammonium and intraluminal binding sites selective of ammoniu...

  4. Mass transfer characteristics of a structured packing for ammonia rectification in ammonia-water absorption refrigeration systems

    Energy Technology Data Exchange (ETDEWEB)

    Sieres, Jaime; Fernandez-Seara, Jose [Area de Maquinas y Motores Termicos, E.T.S. de Ingenieros Industriales, University of Vigo, Campus Lagoas-Marcosende N9, 36310 Vigo (Spain)

    2007-01-15

    In ammonia-water absorption refrigeration systems a purification process of the vapours produced in the generator is required. One type of equipment to carry out the purification process is a packed column. However, detailed experimental studies at the normal operating conditions found in ammonia-water absorption refrigeration systems have not been found. An experimental facility has been designed and built to study the ammonia-water rectification in packed columns. Experimental tests have been performed at the normal operating conditions found in the high-pressure stage of a small power ammonia-water absorption refrigeration system. In this paper, the experimental set-up is described and experimental results of the height equivalent to a theoretical plate (HETP) and the volumetric mass transfer coefficient of a rectifying section with the Sulzer BX packing are presented. The HETP values and the experimental mass transfer coefficients are compared with different data and correlations proposed in the literature; it has been found that the differences are appreciable. (author)

  5. Counteracting ammonia inhibition during anaerobic digestion by recovery using submersible microbial desalination cell

    DEFF Research Database (Denmark)

    Zhang, Yifeng; Angelidaki, Irini

    2015-01-01

    Ammonia inhibition is one of the most frequent and serious problems in biogas plants. In this study, a novel hybrid system consisting of a submersible microbial desalination cell (SMDC) and a continuous stirred tank reactor (CSTR) was developed for counteracting ammonia inhibition during anaerobic...... digestion (AD) with simultaneous in situ ammonia recovery and electricity production. The SMDC was powered by acetate in a buffer solution, while synthetic ammonia-rich wastewater was used as the feeding of the CSTR. Under continuous operation, ammonia recovery rate of 86 g-N/m2 /day and current density...

  6. Ammonia Station Ammonia Spill Contingency Plan Analysis%氨站氨泄漏事故应急方案分析

    Institute of Scientific and Technical Information of China (English)

    胥永

    2015-01-01

    Ammonia as an important chemical raw materials in modern chemical production plays an increasingly important role, but also more and more ammonia spill. By analyzing the ammonia leak hazards emergency plan proposed ammonia spill.%液氨作为一种重要的化工原料,在现代化工生产中扮演着越来越重要的角色,但液氨泄漏事故也越来越多。通过分析液氨泄漏的危害,提出了液氨泄漏事故的应急处置方案。

  7. Single-catalyst high-weight% hydrogen storage in an N-heterocycle synthesized from lignin hydrogenolysis products and ammonia

    Science.gov (United States)

    Forberg, Daniel; Schwob, Tobias; Zaheer, Muhammad; Friedrich, Martin; Miyajima, Nobuyoshi; Kempe, Rhett

    2016-10-01

    Large-scale energy storage and the utilization of biomass as a sustainable carbon source are global challenges of this century. The reversible storage of hydrogen covalently bound in chemical compounds is a particularly promising energy storage technology. For this, compounds that can be sustainably synthesized and that permit high-weight% hydrogen storage would be highly desirable. Herein, we report that catalytically modified lignin, an indigestible, abundantly available and hitherto barely used biomass, can be harnessed to reversibly store hydrogen. A novel reusable bimetallic catalyst has been developed, which is able to hydrogenate and dehydrogenate N-heterocycles most efficiently. Furthermore, a particular N-heterocycle has been identified that can be synthesized catalytically in one step from the main lignin hydrogenolysis product and ammonia, and in which the new bimetallic catalyst allows multiple cycles of high-weight% hydrogen storage.

  8. Single-catalyst high-weight% hydrogen storage in an N-heterocycle synthesized from lignin hydrogenolysis products and ammonia.

    Science.gov (United States)

    Forberg, Daniel; Schwob, Tobias; Zaheer, Muhammad; Friedrich, Martin; Miyajima, Nobuyoshi; Kempe, Rhett

    2016-10-20

    Large-scale energy storage and the utilization of biomass as a sustainable carbon source are global challenges of this century. The reversible storage of hydrogen covalently bound in chemical compounds is a particularly promising energy storage technology. For this, compounds that can be sustainably synthesized and that permit high-weight% hydrogen storage would be highly desirable. Herein, we report that catalytically modified lignin, an indigestible, abundantly available and hitherto barely used biomass, can be harnessed to reversibly store hydrogen. A novel reusable bimetallic catalyst has been developed, which is able to hydrogenate and dehydrogenate N-heterocycles most efficiently. Furthermore, a particular N-heterocycle has been identified that can be synthesized catalytically in one step from the main lignin hydrogenolysis product and ammonia, and in which the new bimetallic catalyst allows multiple cycles of high-weight% hydrogen storage.

  9. Autotrophic ammonia oxidation at low pH through urea hydrolysis.

    Science.gov (United States)

    Burton, S A; Prosser, J I

    2001-07-01

    Ammonia oxidation in laboratory liquid batch cultures of autotrophic ammonia oxidizers rarely occurs at pH values less than 7, due to ionization of ammonia and the requirement for ammonium transport rather than diffusion of ammonia. Nevertheless, there is strong evidence for autotrophic nitrification in acid soils, which may be carried out by ammonia oxidizers capable of using urea as a source of ammonia. To determine the mechanism of urea-linked ammonia oxidation, a ureolytic autotrophic ammonia oxidizer, Nitrosospira sp. strain NPAV, was grown in liquid batch culture at a range of pH values with either ammonium or urea as the sole nitrogen source. Growth and nitrite production from ammonium did not occur at pH values below 7. Growth on urea occurred at pH values in the range 4 to 7.5 but ceased when urea hydrolysis was complete, even though ammonia, released during urea hydrolysis, remained in the medium. The results support a mechanism whereby urea enters the cells by diffusion and intracellular urea hydrolysis and ammonia oxidation occur independently of extracellular pH in the range 4 to 7.5. A proportion of the ammonia produced during this process diffuses from the cell and is not subsequently available for growth if the extracellular pH is less than 7. Ureolysis therefore provides a mechanism for nitrification in acid soils, but a proportion of the ammonium produced is likely to be released from the cell and may be used by other soil organisms.

  10. Decreases in ammonia volatilization in response to greater plant diversity in microcosms of constructed wetlands

    Science.gov (United States)

    Luo, Bin; Ge, Ying; Han, Wenjuan; Fan, Xing; Ren, Yuan; Du, Yuanyuan; Shi, Mengmeng; Chang, Jie

    2016-10-01

    Ammonia volatilization from wastewaters with a high concentration of ammonium is a serious environmental and health problem. Constructed wetlands (CWs) are widely used for treating wastewater, and plant diversity clearly improves some functions of ecosystem such as nitrogen removal. However, whether plant diversity can affect ammonia volatilization from wastewater is still unknown. In this study, we conducted a microcosm experiment with different plant diversity treatments using four plant species. Results showed that, (1) ammonia volatilization decreased with increasing plant species richness; (2) ammonia volatilization from systems containing Rumex japonicus was lower than other systems; and (3) ammonia volatilization was affected more by species composition than species richness. This paper is the first to report that ammonia volatilization is reduced by plant diversity, and that some plant species combinations are important to reduce ammonia volatilization from CWs when treating wastewater.

  11. Promoted Ru on high-surface area graphite for efficient miniaturized production of hydrogen from ammonia

    DEFF Research Database (Denmark)

    Sørensen, Rasmus Zink; Klerke, Asbjørn; Quaade, Ulrich

    2006-01-01

    Promoted Ru/C catalysts for decomposition of ammonia are incorporated into micro-fabricated reactors for the first time. With the reported preparation technique, the performance is increased more than two orders of magnitude compared to previously known micro-fabricated reactors for ammonia decom...... studies of both ammonia synthesis and decomposition, and it is shown how proper promotion can facilitate ammonia decomposition at temperatures below 500 K.......Promoted Ru/C catalysts for decomposition of ammonia are incorporated into micro-fabricated reactors for the first time. With the reported preparation technique, the performance is increased more than two orders of magnitude compared to previously known micro-fabricated reactors for ammonia...... decomposition. The catalytic activities for production of hydrogen from ammonia are determined for different promoters and promoter levels on graphite supported ruthenium catalysts. The reactivity trends of the Ru/C catalysts promoted with Cs and Ba are in excellent agreement with those known from earlier...

  12. Nitrogen removal and microbial characteristics in CANON biofilters fed with different ammonia levels.

    Science.gov (United States)

    Liang, Yuhai; Li, Dong; Zhang, Xiaojing; Zeng, Huiping; Yang, Zhuo; Cui, Shaoming; Zhang, Jie

    2014-11-01

    The nitrogen removal performance and microbial characteristics of four completely autotrophic nitrogen removal over nitrite (CANON) biofilters were investigated. These four reactors were simultaneously seeded from a stable CANON biofilter with a seeding ratio of 1:1, which were fed with different ammonia levels. Results suggested that with the ammonia of 200-400 mg L(-1), aerobic ammonia-oxidizing bacteria (AerAOB) and anaerobic ammonia-oxidizing bacteria (AnAOB) could perform harmonious work. The bioactivity and population of the two groups of bacteria were both high, which then resulted in excellent nitrogen removal, while too low or too high ammonia would both lead to worse performance. When ammonia was too high, the bioactivity, biodiversity and population of AerAOB all decreased and then resulted in the lowest nitrogen removal. Nitrosomonas and Candidatus Brocadia were detected as predominant functional microbes in all the four reactors. Finally, strategies for treating sewage with different ammonia levels were proposed.

  13. Effect of ammonia on ozone-initiated formation of indoor secondary products with emissions from cleaning products

    Science.gov (United States)

    Huang, Yu; Lee, Shun Cheng; Ho, Kin Fai; Ho, Steven Sai Hang; Cao, Nanying; Cheng, Yan; Gao, Yuan

    2012-11-01

    Biogenic volatile organic compounds (BVOCs) emitted from cleaning products and air fresheners indoors are prone to oxidation resulting in the formation of secondary pollutants that can pose health risks on residents. Ammonia (NH3) is ubiquitous in ambient and indoor environments. In this study, we investigated the effect of ammonia (NH3) on secondary pollutants formation from the ozonolysis of BVOCs emitted from cleaning products including floor cleaner (FC), kitchen cleaner (KC) and dishwashing detergent (DD) in a large environmental chamber. Our results demonstrated that the presence of NH3 (maximum concentration is 240 ppb) could significantly enhance secondary organic aerosols (SOAs) formation from the ozonolysis of all the three categories of cleaning products. For example, for the FC sample, the maximum total particle concentration was up to 2.0 × 104 # cm-3 in the presence of NH3, while it was 1.3 × 104 # cm-3 which was 35% lower without NH3. However, it was found that the extent of NH3 effect on SOAs formation from the ozonolysis of BVOCs emissions was component-dependent. The presence of NH3 in the reaction systems could increase the consumptions of d-limonene that is the dominant BVOC species as identified in cleaning products. The percent yields (%) of secondary carbonyl compounds generated from the ozonolysis of BVOCs emitted from three categories of cleaning products were identified in the presence and absence of NH3, respectively. The increase in SOAs particle number concentration can be attributed to the formation of condensable salts from reactions between NH3 and organic compounds generated from the BVOCs ozonolysis processes. By investigating the NH3 effect on the ozonolysis of BVOCs mixtures in contrast to the chemistry of individual compounds, a better assessment can be made of the overall impact cleaning products have on real indoor environments.

  14. Improved process model for ammonia volatilization from anaerobic swine lagoons under varying wind speeds and gas bubbling

    Science.gov (United States)

    Ammonia volatilization from treatment lagoons varies widely with the lagoon water total ammonia concentration, pH, temperature, suspended solids, atmospheric ammonia concentration above the water surface, and wind speed. Ammonia emissions were estimated with a process-based mechanistic model using a...

  15. [Study on Ammonia Emission Rules in a Dairy Feedlot Based on Laser Spectroscopy Detection Method].

    Science.gov (United States)

    He, Ying; Zhang, Yu-jun; You, Kun; Wang, Li-ming; Gao, Yan-wei; Xu, Jin-feng; Gao, Zhi-ling; Ma, Wen-qi

    2016-03-01

    It needs on-line monitoring of ammonia concentration on dairy feedlot to disclose ammonia emissions characteristics accurately for reducing ammonia emissions and improving the ecological environment. The on-line monitoring system for ammonia concentration has been designed based on Tunable Diode Laser Absorption Spectroscopy (TDLAS) technology combining with long open-path technology, then the study has been carried out with inverse dispersion technique and the system. The ammonia concentration in-situ has been detected and ammonia emission rules have been analyzed on a dairy feedlot in Baoding in autumn and winter of 2013. The monitoring indicated that the peak of ammonia concentration was 6.11 x 10(-6) in autumn, and that was 6.56 x 10(-6) in winter. The concentration results show that the variation of ammonia concentration had an obvious diurnal periodicity, and the general characteristic of diurnal variation was that the concentration was low in the daytime and was high at night. The ammonia emissions characteristic was obtained with inverse dispersion model that the peak of ammonia emissions velocity appeared at noon. The emission velocity was from 1.48 kg/head/hr to 130.6 kg/head/hr in autumn, and it was from 0.004 5 kg/head/hr to 43.32 kg/head/hr in winter which was lower than that in autumn. The results demonstrated ammonia emissions had certain seasonal differences in dairy feedlot scale. In conclusion, the ammonia concentration was detected with optical technology, and the ammonia emissions results were acquired by inverse dispersion model analysis with large range, high sensitivity, quick response without gas sampling. Thus, it's an effective method for ammonia emissions monitoring in dairy feedlot that provides technical support for scientific breeding.

  16. Chicken barn climate and hazardous volatile compounds control using simple linear regression and PID

    Science.gov (United States)

    Abdullah, A. H.; Bakar, M. A. A.; Shukor, S. A. A.; Saad, F. S. A.; Kamis, M. S.; Mustafa, M. H.; Khalid, N. S.

    2016-07-01

    The hazardous volatile compounds from chicken manure in chicken barn are potentially to be a health threat to the farm animals and workers. Ammonia (NH3) and hydrogen sulphide (H2S) produced in chicken barn are influenced by climate changes. The Electronic Nose (e-nose) is used for the barn's air, temperature and humidity data sampling. Simple Linear Regression is used to identify the correlation between temperature-humidity, humidity-ammonia and ammonia-hydrogen sulphide. MATLAB Simulink software was used for the sample data analysis using PID controller. Results shows that the performance of PID controller using the Ziegler-Nichols technique can improve the system controller to control climate in chicken barn.

  17. Manufacture of a Polyaniline Nanofiber Ammonia Sensor Integrated with a Readout Circuit Using the CMOS-MEMS Technique

    Science.gov (United States)

    Liu, Mao-Chen; Dai, Ching-Liang; Chan, Chih-Hua; Wu, Chyan-Chyi

    2009-01-01

    This study presents the fabrication of a polyaniline nanofiber ammonia sensor integrated with a readout circuit on a chip using the commercial 0.35 μm complementary metal oxide semiconductor (CMOS) process and a post-process. The micro ammonia sensor consists of a sensing resistor and an ammonia sensing film. Polyaniline prepared by a chemical polymerization method was adopted as the ammonia sensing film. The fabrication of the ammonia sensor needs a post-process to etch the sacrificial layers and to expose the sensing resistor, and then the ammonia sensing film is coated on the sensing resistor. The ammonia sensor, which is of resistive type, changes its resistance when the sensing film adsorbs or desorbs ammonia gas. A readout circuit is employed to convert the resistance of the ammonia sensor into the voltage output. Experimental results show that the sensitivity of the ammonia sensor is about 0.88 mV/ppm at room temperature. PMID:22399944

  18. Manufacture of a Polyaniline Nanofiber Ammonia Sensor Integrated with a Readout Circuit Using the CMOS-MEMS Technique

    Directory of Open Access Journals (Sweden)

    Chyan-Chyi Wu

    2009-02-01

    Full Text Available This study presents the fabrication of a polyaniline nanofiber ammonia sensor integrated with a readout circuit on a chip using the commercial 0.35 mm complementary metal oxide semiconductor (CMOS process and a post-process. The micro ammonia sensor consists of a sensing resistor and an ammonia sensing film. Polyaniline prepared by a chemical polymerization method was adopted as the ammonia sensing film. The fabrication of the ammonia sensor needs a post-process to etch the sacrificial layers and to expose the sensing resistor, and then the ammonia sensing film is coated on the sensing resistor. The ammonia sensor, which is of resistive type, changes its resistance when the sensing film adsorbs or desorbs ammonia gas. A readout circuit is employed to convert the resistance of the ammonia sensor into the voltage output. Experimental results show that the sensitivity of the ammonia sensor is about 0.88 mV/ppm at room temperature

  19. Chemical ionization mass spectrometer (CIMS for ambient measurements of ammonia

    Directory of Open Access Journals (Sweden)

    D. R. Benson

    2010-03-01

    Full Text Available This study describes a chemical ionization mass spectrometer (CIMS for fast response, in-situ measurements for gas phase ammonia. Protonated ethanol ions were used as the ion-molecule reaction reagent. The CIMS sensitivity was estimated to be between 4–25 Hz/pptv with 30% uncertainty. The instrument background was below 1 ppbv and at lowest was 300 pptv. The uncertainty associated with the instrumental background was less than 30 pptv under the optimized experimental conditions. The time response was less than 30 s, and the detection limit was approximately 60 pptv. This CIMS was used to measure the ambient NH3 in Kent, Ohio, for several weeks throughout three seasons. The measured ammonia mixing ratios were usually at the sub-ppbv level, and higher during the spring (200±120 pptv than in the winter (60±75 pptv and fall (150±80 pptv.

  20. Ammonia dynamics in magnesium ammine from DFT and neutron scattering

    DEFF Research Database (Denmark)

    Tekin, Adem; Hummelshøj, Jens Strabo; Jacobsen, Hjalte Sylvest;

    2010-01-01

    Energy storage in the form of ammonia bound in metal salts, so-called metal ammines, combines high energy density with the possibility of fast and reversible NH3 ab- and desorption kinetics. The mechanisms and processes involved in the NH3 kinetics are investigated by density functional theory (DFT...... structure for the uncharacterized low temperature phase of Mg(NH3)(6)Cl-2. It is found from DFT that the rotation of ammonia in the hexammine complex (n = 6) requires an activation energy of 0.09 eV in the low temperature phase of Mg(NH3)(6)Cl-2 and 0.002-0.12 eV in the high temperature phases; effectively......, 1 systems. DFT calculations involving bulk diffusion of NH3 correctly reproduces the trends observed in the experimental desorption enthalpies. In particular, for n = 6, 2, 1, there is a good agreement between activation barriers and experimental enthalpies. These results indicate...