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Sample records for ammonium compounds

  1. Betaines and related ammonium compounds in chestnut (Castanea sativa Mill.).

    Science.gov (United States)

    Servillo, Luigi; Giovane, Alfonso; Casale, Rosario; Balestrieri, Maria Luisa; Cautela, Domenico; Paolucci, Marina; Siano, Francesco; Volpe, Maria Grazia; Castaldo, Domenico

    2016-04-01

    Chestnut fruits, being poor of simple sugars and consisting mainly of fibers and starch, are among the constituents of Mediterranean diet. While numerous studies report on content of proteins and amino acids in chestnut, no one has appeared so far on betaines, an important class of nitrogen compounds ubiquitous in plants for their protective action in response to abiotic stress. In this study, we analyzed by HPLC-ESI-tandem mass spectrometry, in fruits and flours of varieties of chestnut cultivated in Italy, the composition of betaines and ammonium compounds intermediates of their biosynthesis. Besides the parent amino acids, the compounds quantified were choline, glycerophosphocholine, phosphocholine, glycine betaine, N-methylproline, proline betaine (stachydrine), β-alanine betaine, 4-guanidinobutyric acid, trigonelline, N,N,N-trimethyllysine. Interestingly, some uncommon derivatives of pipecolic acid, such as N-methylpipecolic acid, 4-hydroxypipecolic acid and 4-hydroxy-N-methylpipecolic acid were identified for the first time in chestnut samples and characterized by MS(n) tandem mass spectrometry.

  2. EVALUATION OF THE ANTIMICROBIAL EFFECTS OF NEW HETEROCYCLIC BIS-QUATERNARY AMMONIUM COMPOUNDS ON BIOFILMS

    Directory of Open Access Journals (Sweden)

    OANA E. CONSTANTIN

    2016-07-01

    Full Text Available Considering the well-known mechanism of adaptable resistance of microorganisms to chemical compounds through biofilms formation and the widespread use of N-heterocyclic quaternary ammonium salts (QAC as disinfectants, in this study we have evaluate the effect of 8 newly synthesized symmetrical and unsymmetrical diquaternary ammonium salts of 1,2-bis-(4-pyridil-ethane on bacterial biofilms produced by three different bacterial strains. The effect of the exposure to quaternary ammonium salts on biofilm communities was investigated within biofilms obtained in a conventional testing system, on stainless steel and glass surfaces. Differential plate counts were used to characterize the developed communities and the effects of QAC exposure and the results were correlated with epifluorescence microphotographs. The data obtained revealed a significant reduction of bacterial cells in the biofilms tested with 4-7 log CFU for all the QAC.

  3. Critical Coalescence Concetration (CCC as a parameter for evaluation of selected quaternary ammonium compounds

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    Danuta Szyszka

    2013-10-01

    Full Text Available The objective of this paper was to determine the Critical Coalescence Concentration (CCC of surfactants such as N(dodecyloxycarboxymethyl N,N,N-(trimethylammonium bromide (DMGM- 12, N-[2-(dodecyoxycarboxyethyl] N,N,N-(trimethylammonium bromide (DMALM-12 and N-[3- (dodecanoyloxycarboxyprophyl] N,N,N-(trimethylammonium bromide (DMPM-11. The surfactants used represent quaternary ammonium compounds containing a hydrophobic moiety with an ester group (commonly known as “esterquats”. The CCC value was determined by analysis of the relationship between concentration of surfactant and average air bubble diameter. The values of the critical coalescence concentration (CCC were estimated using a graphical method.

  4. Structure and luminescent properties of complex compounds of tellurium(IV) with ammonium bases

    Science.gov (United States)

    Sedakova, T. V.; Mirochnik, A. G.

    2015-07-01

    Using tellurium(IV) complex compounds with outer-sphere ammonium cations as an example, we have studied the interrelation between their geometric structure and spectral-luminescent properties. In the series of compounds of tellurium(IV), which are characterized by the island octahedral coordination of Te(IV) ions, the luminescence intensity has been found to depend on the degree of distortion of the coordination polyhedron of the Te(IV) ion, the position of the A band in diffuse reflection spectra, and the energy of the luminescence transition 3 P 1 → 1 S 0 of the tellurium(IV) ion. We have revealed that the considered Te(IV) complexes possess reversible thermochromic properties.

  5. Identification of quaternary ammonium compounds as potent inhibitors of hERG potassium channels

    International Nuclear Information System (INIS)

    The human ether-a-go-go-related gene (hERG) channel, a member of a family of voltage-gated potassium (K+) channels, plays a critical role in the repolarization of the cardiac action potential. The reduction of hERG channel activity as a result of adverse drug effects or genetic mutations may cause QT interval prolongation and potentially leads to acquired long QT syndrome. Thus, screening for hERG channel activity is important in drug development. Cardiotoxicity associated with the inhibition of hERG channels by environmental chemicals is also a public health concern. To assess the inhibitory effects of environmental chemicals on hERG channel function, we screened the National Toxicology Program (NTP) collection of 1408 compounds by measuring thallium influx into cells through hERG channels. Seventeen compounds with hERG channel inhibition were identified with IC50 potencies ranging from 0.26 to 22 μM. Twelve of these compounds were confirmed as hERG channel blockers in an automated whole cell patch clamp experiment. In addition, we investigated the structure-activity relationship of seven compounds belonging to the quaternary ammonium compound (QAC) series on hERG channel inhibition. Among four active QAC compounds, tetra-n-octylammonium bromide was the most potent with an IC50 value of 260 nM in the thallium influx assay and 80 nM in the patch clamp assay. The potency of this class of hERG channel inhibitors appears to depend on the number and length of their aliphatic side-chains surrounding the charged nitrogen. Profiling environmental compound libraries for hERG channel inhibition provides information useful in prioritizing these compounds for cardiotoxicity assessment in vivo.

  6. Formation of nitrate and ammonium ions in titanium dioxide mediated photocatalytic degradation of organic compounds containing nitrogen atoms

    Energy Technology Data Exchange (ETDEWEB)

    Low, G.K.-C.; McEvoy, S.R.; Matthews, R.W. (CSIRO Division of Coal and Energy Technology, Menai (Australia))

    1991-03-01

    The photocatalytic oxidation of a related series of primary, secondary, and tertiary amines and other nitrogen- and sulfur-containing organic compounds over a UV-illuminated film of TiO{sub 2} has been studied. The compounds were as follows: n-pentylamine, piperidine, pyridine, phenylalanine, desipramine, thioridazine, penicillamine, isosorbide dinitrate, 4-nitrocatechol, 2,4-dinitrophenol, cyclophosphamide, 5-fluorouracil, atrazine, ethylenediaminetetracetic acid, and tetrabutylammonium phosphate. Both ammonium and nitrate ions were formed. The relative concentration of the two ions depended on the nature of the nitrogen in a compound, but was also influenced by the illumination time and concentration of the solute. It was found that for n-pentylamine, piperidine and pyridine, the rate of formation of ammonium ions was n-pentylamine {much gt} pyridine > piperidine. The order of rates of nitrate formation was pyridine = piperidine {much gt} pentylamine. For n-pentylamine the rate of formation of ammonium ions was {approximately}100 times that of nitrate.

  7. Amines and ammonium compounds. CXCVIII. Reaction of ammonium salts containing a 2-alkynyl group with bromine and iodine

    Energy Technology Data Exchange (ETDEWEB)

    Gyul' nazaryan, A.K.; Khachatryan, N.G.; Saakyan, T.A.; Kinoyan, F.S.; Panosyan, G.A.; Babayan, A.T.

    1988-08-10

    The reactions of monoammonium, 1,4-and 1,5-bistertiaryammonium, and bisquaternary ammonium salts containing a 2-alkynyl group with bromine and iodine were studied. It was shown that these salts form molecular complexes with iodine and that addition of iodine at the triple bond does not occur. In reaction with bromine in all cases except 1,4-bistrimethylammonio-2-butyne dihalides one molecule of the halogen adds at the triple bond with the formation of salts containing the 2,3-dibromo-2-alkenyl group, which then form a 1:1 complex with bromine.

  8. Preparation and Characterization of Montmorillonite Intercalation Compounds with Quaternary Ammonium Surfactant: Adsorption Effect of Zearalenone

    Directory of Open Access Journals (Sweden)

    Yujin Li

    2014-01-01

    Full Text Available Montmorillonite (Mt was used as the original material to prepare intercalation compounds with quaternary ammonium surfactant (QAS. The adsorption of zearalenone (ZEA onto Mt and organomodified Mt was investigated in vitro. Effects of QAS in binding ZEA were studied. By the method of intercalation with dioctadecylmethylbenzylammonium chloride (DOMBAC, the sample exhibited the highest adsorption rate of ZEA (93.2% which was much higher than that of Mt (10.5%. Several methods were adopted to characterize samples, including XRD, TG/DSC, N2 adsorption/desorption, and FTIR. Adsorption isotherm parameters were obtained from Langmuir and Freundlich and the adsorption data fitted better to Langmuir. All results indicate that organomodified Mt has great potential to be a high-performance material to control ZEA contamination.

  9. Antibacterial activity of reactive quaternary ammonium compounds in solution and in nonleachable coatings

    NARCIS (Netherlands)

    Gozzelino, G.; Romero Tobar, D.E.; Chaitiemwong, N.; Hazeleger, W.C.; Beumer, R.R.

    2011-01-01

    Antibacterial polymers suitable for coating applications without leaching of the biocidal component have been obtained by UV copolymerization of acrylic resins with acrylic monomers containing quaternary ammonium moieties. Suitable reactive biocides, based on quaternary ammonium monomers (QAMs), end

  10. Synthesis and characterization of a new class of energetic compounds - ammonium nitriminotetrazolates

    Energy Technology Data Exchange (ETDEWEB)

    Klapoetke, Thomas M.; Laub, Hans A.; Stierstorfer, Joerg [Chair of Inorganic Chemistry, Energetic Materials Research, Ludwig-Maximilian University of Munich, Department Chemistry and Biochemistry, Munich (Germany)

    2008-12-15

    1-Methyl-5-nitriminotetrazole (1) and 2-methyl-5-nitraminotetrazole (2) obtained by nitration of 1-methyl-5-aminotetrazole (3) and 2-methyl-5-aminotetrazole (4) were deprotonated using aqueous ammonia solution yielding the energetic compounds, ammonium 1-methyl-5-nitriminotetrazolate (5) and ammonium 2-methyl-5-nitriminotetrazolate (6). The nitrogen-rich salts were tested and characterized comprehensively using vibrational spectroscopy (Infrared (IR) and Raman), multinuclear ({sup 1}H, {sup 13}C, {sup 14}N, and {sup 15}N) NMR spectroscopy, and elemental analysis. The molecular structures in the crystalline state were determined using low temperature single crystal X-ray diffraction. The thermal behavior and the decompositions were investigated using differential scanning calorimetry (DSC) and gas IR spectroscopy. The heats of formation were calculated using bomb calorimetric measurements. In addition, the relevant detonation parameters, like the detonation pressure and velocity of detonation were calculated using the software EXPLO5 outperforming the values of TNT. Last but not least the sensitivities were determined using BAM methods showing moderate values against impact and friction (drophammer and friction tester) and the long-term stabilities were tested using Flexy Thermal safety calorimetry (TSC). X-ray crystallography: 5: monoclinic, P2{sub 1}/c, a=370.06(2) pm, b=2079.06(9) pm, c=859.69(5) pm, {beta}=99.120(5) , V=65306(6) pm{sup 3}, Z=4, {rho}{sub calc}=1.639 g cm{sup -3}; 6: monoclinic, P2{sub 1}, a=365.39(2) pm, b= 788.82(5) pm, c=1124.95(7) pm, {beta}=91.818(6), V=32408(3) pm{sup 3}, Z=2, {rho}{sub calc}=1.651 g cm{sup -3}. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  11. Survival of adhering staphylococci during exposure to a quaternary ammonium compound evaluated by using atomic force microscopy imaging

    NARCIS (Netherlands)

    Crismaru, Mihaela; Asri, Lia ATW; Loontjens, Jacobus; Krom, Bastiaan P; de Vries, Jacob; van der Mei, Henderina; Busscher, Hendrik

    2011-01-01

    Effects of a quaternary ammonium compound (QAC) on the survival of adhering staphylococci on a surface were investigated using atomic force microscopy (AFM). Four strains with different minimal inhibitory concentrations (MIC) and minimal bactericidal concentrations (MBC) for the QAC were exposed to

  12. Quaternary ammonium compounds as water channel blockers. Specificity, potency, and site of action.

    Science.gov (United States)

    Detmers, Frank J M; de Groot, Bert L; Müller, E Matthias; Hinton, Andrew; Konings, Irene B M; Sze, Mozes; Flitsch, Sabine L; Grubmüller, Helmut; Deen, Peter M T

    2006-05-19

    Excessive water uptake through Aquaporins (AQP) can be life-threatening and reversible AQP inhibitors are needed. Here, we determined the specificity, potency, and binding site of tetraethylammonium (TEA) to block Aquaporin water permeability. Using oocytes, externally applied TEA blocked AQP1/AQP2/AQP4 with IC50 values of 1.4, 6.2, and 9.8 microM, respectively. Related tetraammonium compounds yielded some (propyl) or no (methyl, butyl, or pentyl) inhibition. TEA inhibition was lost upon a Tyr to Phe amino acid switch in the external water pore of AQP1/AQP2/AQP4, whereas the water permeability of AQP3 and AQP5, which lack a corresponding Tyr, was not blocked by TEA. Consistent with experimental data, multi-nanosecond molecular dynamics simulations showed one stable binding site for TEA, but not tetramethyl (TMA), in AQP1, resulting in a nearly 50% water permeability inhibition, which was reduced in AQP1-Y186F due to effects on the TEA inhibitory binding region. Moreover, in the simulation TEA interacted with charged residues in the C (Asp128) and E (Asp185) loop, and the A(Tyr37-Asn42-Thr44) loop of the neighboring monomer, but not directly with Tyr186. The loss of TEA inhibition in oocytes expressing properly folded AQP1-N42A or -T44A is in line with the computationally predicted binding mode. Our data reveal that the molecular interaction of TEA with AQP1 differs and is about 1000-fold more effective on AQPs than on potassium channels. Moreover, the observed experimental and simulated similarities open the way for rational design and virtual screening for AQP-specific inhibitors, with quaternary ammonium compounds in general, and TEA in particular as a lead compound. PMID:16551622

  13. Interaction of pinaverium (a quaternary ammonium compound) with 1,4-dihydropyridine binding sites in rat ileum smooth muscle.

    OpenAIRE

    Feron, Olivier; Wibo, Maurice; Christen, M O; Godfraind, Theophile

    1992-01-01

    1. The interaction of pinaverium bromide, a quaternary ammonium compound, with binding sites for (L-type) calcium channel blockers was investigated in rat ileum smooth muscle. 2. Pinaverium inhibited [3H]-(+)-PN200-110 ([3H]-(+)-isradipine) specific binding to tissue homogenates incompletely (Ki 0.38 microM; maximal inhibition 80%). In contrast, binding to single cell preparations (obtained by collagenase treatment) and to saponin-treated homogenates was completely inhibited. These data are c...

  14. Catalyst used in 1,2-epoxyalkane preparation is obtained by heating tetraalkyl ammonium salts, tetraalkyl siloxanes and amines, calcining and treating with a tetraalkoxy compound

    DEFF Research Database (Denmark)

    2001-01-01

    NOVELTY - The catalyst, used in 1,2-epoxyalkane preparation, is obtained by heat treating an aqueous composition comprising tetraalkyl ammonium salts, tetraalkyl siloxanes and amines, removing the template by calcining and treating with a tetraalkoxy compound......NOVELTY - The catalyst, used in 1,2-epoxyalkane preparation, is obtained by heat treating an aqueous composition comprising tetraalkyl ammonium salts, tetraalkyl siloxanes and amines, removing the template by calcining and treating with a tetraalkoxy compound...

  15. Exchange of reactive nitrogen compounds: concentrations and fluxes of total ammonium and total nitrate above a spruce forest canopy

    Directory of Open Access Journals (Sweden)

    V. Wolff

    2009-11-01

    Full Text Available Total ammonium (tot-NH4+ and total nitrate (tot-NO3 provide a chemically conservative quantity in the measurement of exchange processes of reactive nitrogen compounds ammonia (NH3, particulate ammonium (NH4+, nitric acid (HNO3, and particulate nitrate (NO3, using the aerodynamic gradient method. Total fluxes were derived from concentration differences of total ammonium (NH3 and NH4+ and total nitrate (HNO3 and NO3 measured at two levels. Gaseous species and related particulate compounds were measured selectively, simultaneously and continuously above a spruce forest canopy in south-eastern Germany in summer 2007. Measurements were performed using a wet-chemical two-point gradient instrument, the GRAEGOR. Median concentrations of NH3, HNO3, NH4, and NO3 were 0.57, 0.12, 0.76, and 0.48 μg m−3, respectively. Total ammonium and total nitrate fluxes showed large variations depending on meteorological conditions, with concentrations close to zero under humid and cool conditions and higher concentrations under dry conditions. Mean fluxes of total ammonium and total nitrate in September 2007 were directed towards the forest canopy and were −65.77 ng m−2 s−1 and −41.02 ng m−2 s−1 (in terms of nitrogen, respectively. Their deposition was controlled by aerodynamic resistances only, with very little influence of surface resistances. Including measurements of wet deposition and findings of former studies at the study site on occult deposition (fog water interception, the total N deposition in September 2007 was estimated to 5.86 kg ha−1.

  16. Exchange of reactive nitrogen compounds: concentrations and fluxes of total ammonium and total nitrate above a spruce canopy

    Directory of Open Access Journals (Sweden)

    V. Wolff

    2010-05-01

    Full Text Available Total ammonium (tot-NH4+ and total nitrate (tot-NO3 provide chemically conservative quantities in the measurement of surface exchange of reactive nitrogen compounds ammonia (NH3, particulate ammonium (NH4+, nitric acid (HNO3, and particulate nitrate (NO3, using the aerodynamic gradient method. Total fluxes were derived from concentration differences of total ammonium (NH3 and NH4+ and total nitrate (HNO3 and NO3 measured at two levels. Gaseous species and related particulate compounds were measured selectively, simultaneously and continuously above a spruce forest canopy in south-eastern Germany in summer 2007. Measurements were performed using a wet-chemical two-point gradient instrument, the GRAEGOR. Median concentrations of NH3, HNO3, NH4+, and NO3 were 0.57, 0.12, 0.76, and 0.48 μg m−3, respectively. Total ammonium and total nitrate fluxes showed large variations depending on meteorological conditions, with concentrations close to zero under humid and cool conditions and higher concentrations under dry conditions. Mean fluxes of total ammonium and total nitrate in September 2007 were directed towards the forest canopy and were −65.77 ng m−2 s−1 and −41.02 ng m−2 s−1 (in terms of nitrogen, respectively. Their deposition was controlled by aerodynamic resistances only, with very little influence of surface resistances. Including measurements of wet deposition and findings of former studies on occult deposition (fog water interception at the study site, the total N deposition in September 2007 was estimated to 5.86 kg ha−1.

  17. Review and phylogenetic analysis of qac genes that reduce susceptibility to quaternary ammonium compounds in Staphylococcus species

    DEFF Research Database (Denmark)

    Wassenaar, Trudy M; Ussery, David; Nielsen, Lene Nørby;

    2015-01-01

    The qac genes of Staphylococcus species encode multidrug efflux pumps: membrane proteins that export toxic molecules and thus increase tolerance to a variety of compounds such as disinfecting agents, including quaternary ammonium compounds (for which they are named), intercalating dyes and some...... described in the literature for qac detection may miss particular qac genes due to lack of DNA conservation. Despite their resemblance in substrate specificity, the Qac proteins belonging to the two protein families have little in common. QacA and QacB are highly conserved in Staphylococcus species, while...... variation, despite their short length, even within the Staphylococcus genus. Phylogenetic analysis of these genes identified similarity to a large number of other SMR members, found in staphylococci as well as in other genera. A number of phylogenetic trees of SMR Qac proteins are presented here, starting...

  18. Toxicity of Ambient Particulate Matter IV: Acute toxicity study in pulmonary hypertensive rats after exposure to model compounds for the secondary aerosol fraction of PM10 - ammonium bisulfate, ferrosulfate and nitrate

    NARCIS (Netherlands)

    Cassee FR; Boere AJF; Fokkens PHB; Dormans JAMA; Bree L van; Rombout PJA; LEO; LPI

    1999-01-01

    This (4th) report on the toxicity of ambient particulate matter (PM) presents effects of the model compounds for PM in ambient air - ammonium bisulfate, ammonium ferrosulfate and ammonium nitrate - on healthy rats and rats with monocrotaline-induced pulmonary hypertension (PH). The objective was bas

  19. Selective removal and inactivation of bacteria by nanoparticle composites prepared by surface modification of montmorillonite with quaternary ammonium compounds.

    Science.gov (United States)

    Khalil, Rowaida K S

    2013-10-01

    The purpose of the present study was to prepare new nanocomposites with antibacterial activities by surface modification of montmorillonite using quaternary ammonium compounds that are widely applied as disinfectants and antiseptics in food-processing environments. The intercalation of four quaternary ammonium compounds namely benzalkonium chloride, cetylpyridinium chloride monohydrate, hexadecyltrimethylammonium bromide, tetraethylammonium chloride hydrate into montmorillonite layers was confirmed by X-ray diffraction. The antibacterial influences of the modified clay variants against important foodborne pathogens differed based on modifiers quantities, microbial cell densities, and length of contact. Elution experiments through 0.1 g of the studied montmorillonite variants indicated that Staphylococcus aureus, Pseudomonas aeroginosa, and Listeria monocytogenes were the most sensitive strains. 1 g of hexadecyltrimethylammonium bromide intercalated montmorillonites demonstrated maximum inactivation of L. monocytogenes populations, with 4.5 log c.f.u./ml units of reduction. In adsorption experiments, 0.1 g of tetraethylammonium chloride hydrate montmorillonite variants significantly reduced the growth of Escherichia coli O157:H7, L. monocytogenes, and S. aureus populations by 5.77, 6.33, and 7.38 log units respectively. Growth of wide variety of microorganisms was strongly inhibited to undetectable levels (food processing plant environments where selectivity in removal and/or inactivation of species in fluid flow streams is desirable. Nevertheless, extensive in vitro and in vivo studies of these new nanocomposites is essential to outpace the understanding of their potential impacts and consequences on human health and the environment if they will make an appearance in commercialized food packaging and containment food materials in the future. PMID:23709187

  20. The Influence of Interfering Substances on the Antimicrobial Activity of Selected Quaternary Ammonium Compounds

    Directory of Open Access Journals (Sweden)

    Paula A. Araújo

    2013-01-01

    Full Text Available Standard cleaning processes may not remove all the soiling typically found in food industry, such as carbohydrates, fats, or proteins. Contaminants have a high impact in disinfection as their presence may reduce the activity of disinfectants. The influence of alginic acid, bovine serum albumin, yeast extract, and humic acids was assessed on the antimicrobial activities of benzalkonium chloride and cetyltrimethyl ammonium bromide against Bacillus cereus vegetative cells and Pseudomonas fluorescens. The bacteria (single and consortium were exposed to surfactants (single and combined in the absence and presence of potential disinfection interfering substances. The antimicrobial effects of the surfactants were assessed based on the bacterial respiratory activity measured by oxygen uptake rate due to glucose oxidation. The tested surfactants were efficient against both bacteria (single and consortium with minimum bactericidal concentrations ranging from 3 to 35 mg·L−1. The strongest effect was caused by humic acids that severely quenched antimicrobial action, increasing the minimum bactericidal concentration of the surfactants on P. fluorescens and the consortium. The inclusion of the other interfering substances resulted in mild interferences in the antibacterial activity. This study clearly demonstrates that humic acids should be considered as an antimicrobial interfering substance in the development of disinfection strategies.

  1. Synthesis of Some New Quaternary Ammonium Compounds Evaluation of their Surface properties and Solubilization Activity

    International Nuclear Information System (INIS)

    Four cationic surfactants were prepared by condensing fatty acid methyl diethanolamine derivatives (C6, CI0, CI2, CI8) with stoichiometric amounts of trimethyl chlorosilane. The surface properties and parameters were investigated to find the relationship between the structure of the hydrophobic portion of such compounds and their efficiency toward solubilization. The properties studied included surface excess concentration (Γmax), critical micelle concentration (cmc). free energy of micellization (ΔGοmic) and adsorption (ΔGοads) in addition to the surface tension (γcmc) at cmc and effectiveness (Πcmc). The values of Γmax, ΔGο mic and ΔGοads were found to increase with increasing number of chain length. while cmc and minimum surface area occupied by one molecule (Amin) were decreased. Solubilization effect of these surfactants on paraffin oil as a non polar solubilizate and biodegradability were studied

  2. Effects of chromium and cobalt compounds on burning rate of ammonium nitrate/hydroxyl-terminated polybutadiene composite propellants. Shosan ammonium/HTPB kei composite suishin'yaku no nensho sokudo ni oyobosu chromium to cobalt kagobutsu no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Hagihara, Y.; Ichikawa, T.; Shinpo, H.; Suzuki, M. (The National Defense Academy, Yokosuka (Japan))

    1991-12-31

    Study was made on the effects of chromium and cobalt compounds on burning rate of AN/HTPB composite propellants by using 14 types of chromium and cobalt compounds as catalysts and it was clear that burning rate of composite propellants increases with all catalysts and increase in burning rate by ammonium dichromate and chromium (III) acetylacetone is significantly large. Pressure exponent for cobalt(II) oxide and cobalt(II) benzoate has decreased but it has increased with other catalysts. Pressure exponent has significantly increased in the case of cobalt 2-ethylhexanoate and cobalt(II) acetylacetone. Effect of compounds on slurry viscosity also has shown the decrease in the viscosity except chromium(III) oxide and cobalt(II,III) oxide, and in the case of cobalt 2-ethylhexanoate the viscosity is significantly low. Drophammer sensitivity of AN is not affected with the added compounds. 4 refs., 3 figs., 4 tabs.

  3. Determination of quaternary ammonium compounds by potentiometric titration with an ionic surfactant electrode: single-laboratory validation.

    Science.gov (United States)

    Price, Randi; Wan, Ping

    2010-01-01

    A potentiometric titration for determining the quaternary ammonium compounds (QAC) commonly found in antimicrobial products was validated by a single laboratory. Traditionally, QACs were determined by using a biphasic (chloroform and water) manual titration procedure. Because of safety considerations regarding chloroform, as well as the subjectivity of color indicator-based manual titration determinations, an automatic potentiometric titration procedure was tested with quaternary nitrogen product formulations. By using the Metrohm Titrando system coupled with an ionic surfactant electrode and an Ag/AgCl reference electrode, titrations were performed with various QAC-containing formulation products/matrixes; a standard sodium lauryl sulfate solution was used as the titrant. Results for the products tested are sufficiently reproducible and accurate for the purpose of regulatory product enforcement. The robustness of the method was measured by varying pH levels, as well as by comparing buffered versus unbuffered titration systems. A quantitation range of 1-1000 ppm quaternary nitrogen was established. Eight commercially available antimicrobial products covering a variety of matrixes were assayed; the results obtained were comparable to those obtained by the manual titration method. Recoveries of 94 to 104% were obtained for spiked samples. PMID:21140668

  4. Interaction of pinaverium (a quaternary ammonium compound) with 1,4-dihydropyridine binding sites in rat ileum smooth muscle.

    Science.gov (United States)

    Feron, O; Wibo, M; Christen, M O; Godfraind, T

    1992-02-01

    1. The interaction of pinaverium bromide, a quaternary ammonium compound, with binding sites for (L-type) calcium channel blockers was investigated in rat ileum smooth muscle. 2. Pinaverium inhibited [3H]-(+)-PN200-110 ([3H]-(+)-isradipine) specific binding to tissue homogenates incompletely (Ki 0.38 microM; maximal inhibition 80%). In contrast, binding to single cell preparations (obtained by collagenase treatment) and to saponin-treated homogenates was completely inhibited. These data are compatible with the view that, in untreated homogenates, 20% of [3H]-(+)-isradipine binding sites are not accessible to pinaverium because it is associated with sealed inside-out vesicles. 3. Pinaverium bromide increased the apparent KD of [3H]-(+)-isradipine binding to saponin-treated homogenates but did not significantly affect the Bmax value. Moreover, the dissociation rate constant of [3H]-(+)-isradipine binding was not changed by pinaverium. These data suggest that pinaverium interacts with the dihydropyridine binding site in a competitive manner. However, in contrast to uncharged dihydropyridine calcium antagonists, pinaverium inhibited, rather than stimulated, [3H]-diltiazem binding to rat brain membranes (at 30-37 degrees C). 4. Although Bmax values of [3H]-(+)-isradipine were similar in homogenates prepared from tissue and cells (collagenase-treated), the KD value was significantly higher in cell homogenates (166 vs 95 pM). Similarly, the Ki value of pinaverium was higher in cell preparations than in tissue homogenates (0.77 vs 0.38 microM). Thus, collagenase can significantly modify the dihydropyridine recognition site.5. The competitive interaction of pinaverium, a permanently charged drug, with [3H]-(+)-isradipine bound to intact cells and its absence of interaction with [3H]-(+)-isradipine bound to sealed inside-out vesicles imply that the dihydropyridine receptor lies near the external surface of the plasma membrane. PMID:1313732

  5. Synthesis and characterization of an energetic compound Cu(Mtta)2(NO3)2 and effect on thermal decomposition of ammonium perchlorate.

    Science.gov (United States)

    Yang, Qi; Chen, Sanping; Xie, Gang; Gao, Shengli

    2011-12-15

    An energetic coordination compound Cu(Mtta)(2)(NO(3))(2) has been synthesized by using 1-methyltetrazole (Mtta) as ligand and its structure has been characterized by X-ray single crystal diffraction. The central copper (II) cation was coordinated by four O atoms from two Mtta ligands and two N atoms from two NO(3)(-) anions to form a six-coordinated and distorted octahedral structure. 2D superamolecular layer structure was formed by the extensive intermolecular hydrogen bonds between Mtta ligands and NO(3)(-) anions. Thermal decomposition process of the compound was predicted based on DSC and TG-DTG analyses results. The kinetic parameters of the first exothermic process of the compound were studied by the Kissinger's and Ozawa-Doyle's methods. Sensitivity tests revealed that the compound was insensitive to mechanical stimuli. In addition, compound was explored as additive to promote the thermal decomposition of ammonium perchlorate (AP) by differential scanning calorimetry.

  6. Study on Compound Sweeteners of Ammonium Glycyrrhetate%甘草酸铵复合甜味剂的复配研究

    Institute of Scientific and Technical Information of China (English)

    豆康宁; 王飞; 罗海澜; 孙发根; 毛爱华

    2014-01-01

    The recipe of ammonium glycyrrhetate,sucralose,erythritol and glycine is optimized by single factor and orthogonal experiments.The research results show that the proportion of compound sweeteners is ammonium glycyrrhetate of 100%,glycine of 12%,erythritol of 10%,sucralose of 2.5%,the taste of ammonium glycyrrhetate compound sweeteners is pure, and the sweetness intensity is about 690 times that of sucrose.%通过单因素和正交试验优化了复合甜味剂甘草酸铵、三氯蔗糖、赤藓糖醇和甘氨酸的配方比例。实验结果表明:甘草酸铵复合甜味剂的配方比例为甘草酸铵100%、甘氨酸12%、赤藓糖醇10%、三氯蔗糖2.5%。该甘草酸铵复合甜味剂甜味比较纯正,甜味强度约为蔗糖的690倍。

  7. Process optimization of rare earth and aluminum leaching from weathered crust elution-deposited rare earth ore with compound ammonium salts

    Institute of Scientific and Technical Information of China (English)

    何正艳; 张臻悦; 余军霞; 徐志高; 池汝安

    2016-01-01

    In order to intensify the leaching process of rare earth (RE) and reduce the impurities in the leachate, ammonium chloride (NH4Cl) and ammonium nitrate (NH4NO3) were mixed as a compound leaching agent to treat the weathered crust elution-deposited RE ore. Effects of molar ratio of NH4Cl and NH4NO3, ammonium (NH4+) concentration, leaching agent pH and flow rate on the leaching process of RE were studied and evaluated by the chromatographic plate theory. Leaching process of the main impurity alu-minium (Al) was also discussed in detail. Results showed that a higher initial ammonium concentration in a certain range could en-hance the mass transfer process of RE and Al by providing a driving force to overcome the resistance of diffusion. pH almost had no effects on the mass transfer efficiency of RE and Al in the range of 4 to 8. The relationship between the flow rate and height equiva-lent to a theoretical plate (HETP) could fit well with the Van Deemter equation, and the flow rate at the lowest HETP was determined. The optimum conditions of column leaching for RE and Al were 1:1 (molar ratio) of NH4Cl and NH4NO3, 0.2 mol/L of ammonium concentration, pH 4–8 of leaching agent and 0.5 mL/min of flow rate. Under this condition, the mass transfer efficiency of RE was improved, but no change was observed for Al compared with the most widely used ammonium sulfate. Moreover, the significant dif-ference value (around 20 mL) of retention volume at the peak concentration between RE and Al provided a possibility for their sepa-ration. It suggested the potential application of the novel compound leaching agent (NH4Cl/NH4NO3). It was found that the relative concentration of RE in the leachate could be easily obtained by monitoring the pH of leachate.

  8. Preparatory of X zeolite (faujasite) with surfactant hexa decyl trimethyl ammonium bromide (HMDTA) for adsorption of organic compounds

    International Nuclear Information System (INIS)

    The water represents one of the most valuable natural resources for the alive beings, since it is the essential component of the alive matter. Also, it is fundamental part of our planet, since is an indispensable element for the integral development of the same one. The demographic growth, the human being's activities and the industrial growth, he/she brings as consequence an increase in the use of the water and the generation of residual waters that successively contaminate the hydrological basins, becoming an environmental problem urgent. The contamination of the water with compound such as phenol and benzene, it is a problem that it requires the search of solutions, since it is of compound not very biodegradable, able to accumulate through the food chains and very toxic to the alive beings that they enter in contact with them (Tolgyessy, 1993). In the human beings it can take place damages in liver and kidney, the Agency of Protection to the Atmosphere of the United States (EPA) it considers that the exhibition for benzene is related with the leukemia, it is also considered as a carcinogen substance. Of the methods that are used for the treatment of polluted waters, it highlights the use of adsorber and one of them is the zeolites, since they are broadly used in those separation processes. The zeolites is crystalline aluminosilicates, they are characterized for to have a big superficial area and for their great capacity of exchange cationic, due to it the process of adsorption depends on these two characteristics, since to the modified being superficially for surfactants cationic it originates an enriched layer of carbon organic, which has the capacity to remove pollutants of the water. The present work outlines as objective to carry out the superficial modification of zeolite X using hexa decyl trimethyl ammonium bromide (HMDTA-Br) to different concentrations, with the purpose of making it useful in the removal of pollutants organic, present in watery solution

  9. Influence of surfactants on the properties of precipitates of difficulty soluble actinide and lanthanide compounds. 1. Ammonium diuranate

    International Nuclear Information System (INIS)

    The main characteristics have been ascertained of the influence of various kinds of surfactants on the properties of a precipitate of ammonium diuranate thrown down by a concentrated ammonia solution from a nitric acid solution of uranyl nitrate. It has been shown that monomolecular cationogenic surfactants have no effect on the properties of the precipitate. Nonionogenic and anionogenic monomolecular surfactants promote an increase of the rate of sedimentation of ammonium diuranate. High-molecular-weight cationogenic surfactants have a negative effect on the rates of sedimentation and filtration of a suspension, and increase the moisture content of a precipitate. The action of high-molecular-weight nonionogenic surfactants is analogous to that of monomolecular surfactants of the same type. It has been shown that the most effective flocculants of ammonium diuranate are anionogenic polyelectrolytes. Low concentrations of these substances in a suspension enable the rates of sedimentation and filtration to be increased and the moisture content of an ammonium diuranate precipitate to be reduced owing to formation of stable flakes possessing elasticity

  10. Research Progress on Analytical Methods of Quaternary Ammonium Compounds%季铵盐类消毒剂及其检测方法的研究进展

    Institute of Scientific and Technical Information of China (English)

    杨艳伟; 朱英

    2011-01-01

    季铵盐类消毒剂是一类重要的化学消毒剂,广泛应用于各个领域,其有关研究和进展一直受到广泛关注.该研究介绍了季铵盐类消毒剂的结构特点、杀菌机制及其影响因素,重点介绍并分析了其主要分析方法(包括滴定法、紫外-可见分光光度法、离子色谱法、液相色谱法和气相色谱质谱法)的测定原理、应用范围及优缺点.%Quaternary ammonium disinfectant is one of important chemical disinfectants and widely used in various fields. Its reaserch as well as development had attracted wide acttentions. In this article the structural features, sterilizing mechanism and influencing factors of quaternary ammonium disinfectant were presented. Several analytical methods of quaternary ammonium compounds including diphasic titration, ultra violet -visible spectrophotometry, ion chromatography,liquid chromatography and gas chromatography-mass spectrometry were introduced in detail. Moreover, the principle, application range, advantage and disadvantage of different methods were discussed.

  11. Adamantane-1-ammonium acetate

    Directory of Open Access Journals (Sweden)

    Elise J. C. de Vries

    2011-06-01

    Full Text Available In the title compound, C10H18N+·C2H3O2−, the ammonium H atoms of the cation are linked to three acetate anions via N—H...O hydrogen bonds, forming a chain structure extending along the b axis.

  12. Toxicity of Ambient Particulate Matter (PM10) I. Acute toxicity study in asthmatic mice following 3-day exposure to ultrafine and fine ammonium bisulfate, a model compound for secondary aerosol fraction of PM10

    NARCIS (Netherlands)

    Cassee FR; Dormans JAMA; Loveren H van; Bree L van; Rombout PJA; LEO; LPI

    1998-01-01

    Presented here is the first in a series of 3-day inhalation studies aimed to generate data on the health effects of inhaled ultrafine and fine ammonium bisulfate aerosols as model compound for the secondary fraction of particulate matter (PM10). Epidemiologic studies identified asthmatics as a risk

  13. Toxicity of Ambient Particulate Matter II. Acute toxicity study in asthmatic mice following 3-day exposure to fine ammonium ferrosulfate, a model compound for secondary aerosol of PM10

    NARCIS (Netherlands)

    Cassee FR; Dormans JAMA; Loveren H van; Bree L van; Rombout PJA; LEO; LPI

    1998-01-01

    In this second report on acute inhalation studies with model compounds for secondary particulate matter, results are presented of a study with fine ammonium ferrosulfate aerosol in asthmatic animals. We hypothesised that an aerosol with a transitional metal could produce enhanced symptoms of asthma.

  14. Bifunctional quaternary ammonium compounds to inhibit biofilm growth and enhance performance for activated carbon air-cathode in microbial fuel cells

    Science.gov (United States)

    Li, Nan; Liu, Yinan; An, Jingkun; Feng, Cuijuan; Wang, Xin

    2014-12-01

    The slow diffusion of hydroxyl out of the catalyst layer as well as the biofouling on the surface of cathode are two problems affecting power for membrane-less air-cathode microbial fuel cells (MFCs). In order to solve both of them simultaneously, here we simply modify activated carbon air-cathode using a bifunctional quaternary ammonium compound (QAC) by forced evaporation. The maximum power density reaches 1041 ± 12 mW m-2 in an unbuffered medium (0.5 g L-1 NaCl), which is 17% higher than the control, probably due to the accelerated anion transport in the catalyst layer. After 2 months, the protein content reduced by a factor of 26 and the power density increases by 33%, indicating that the QAC modification can effectively inhibit the growth of cathodic biofilm and improve the stability of performance. The addition of NaOH and QAC epoxy have a negative effect on power production due to the clogging of pores in catalyst layer.

  15. Determination of quaternary ammonium compounds in oranges and cucumbers using QuEChERS extraction and ultra-performance liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Arrebola-Liébanas, Francisco Javier; Abdo, María Angeles Herrera; Moreno, José Luis Fernandez; Martínez-Vidal, José L; Frenich, Antonia Garrido

    2014-01-01

    A simple and fast method has been developed for determining relevant quaternary ammonium compounds in cucumber and orange samples. The target compounds were benzoalkonium chloride (BAC-10, BAC-12, BAC-14, and BAC-16), didecyldimethylammonium chloride, and benzethonium chloride, all frequently used biocides in the agrifood industry. An extraction based on the buffered Quick, Easy, Cheap, Effective, Rugged, and Safe method and determination by ultra-performance LC/MS/MS that eluted the biocides in less than 5 min were used. The method was fully validated and implemented in a UNE-EN-ISO/IEC 17025 accredited laboratory for its application to the analysis of real samples. Performance characteristics of the method are reported, including an estimation of measurement uncertainty. Calibration curves were set between 0.01 and 0.150 mg/kg, LOD values were always between 0.4 and 1.0 microg/kg, LOQ values were in the range 1-4 microg/kg, recovery was between 81 and 115%, intraday and interday precision were always lower than 17% (expressed as RSD), and expanded uncertainty was always lower than 40%. The validation was accomplished for the two studied matrixes at spiking concentrations of 0.011 and 0.050 mg/kg. The method has been applied to the analysis of 30 cucumber and orange samples that were found to contain concentrations of BAC-12 that ranged between 0.015 and 0.210 mg/kg and of BAC-14 between 0.018 and 0.081 mg/kg. PMID:25145132

  16. 硫磷酸铵复合肥生产技术及配方计算%Production technology of ammonium sulfate phosphate compound fertilizer and its formula calculation

    Institute of Scientific and Technical Information of China (English)

    曾志伟

    2012-01-01

    以洗涤液中的硫酸、磷酸,以及氨、硫酸铵、过磷酸钙生产硫磷酸铵复合肥,对硫磷酸铵物相组成、生产控制的关键因素进行探讨。通过实例定量测算得出:硫酸铵、过磷酸钙用量一定时,控制造粒机出口物料中和度n(N)/n(P)在1.70~1.85、硫酸消耗在220kg/t左右时,生产状况良好,设备运行良好。%Ammonium sulfate phosphate compound fertilizer is produced with sulfuric acid and phosphoric acid from cleaning mixture, ammonia, ammonium sulfate, SSP. The phase composition of ammonium sulfate phosphate and the key factors of production control are discussed. Based on the quantitatively calculation, it is concluded that: when the dosage of ammonium sulfate and single superphosphate is fixed, the material neutralization degree n(N) /n(P) in granulator export is 1.70- 1.85, sulfuric acid consumption is about 220 kg/t, the production condition and equipment operation are good.

  17. Synthesis of enamine-type tetrahydro isoquinoline quaternary ammonium base compounds%烯胺型四氢异喹啉季铵碱化合物的合成

    Institute of Scientific and Technical Information of China (English)

    孙默然; 张秋荣; 杨华

    2011-01-01

    When 1-carboxyl ester substituted and N-alkyl substituted tetrahydroisoquinoline compounds reacted with methyl iodide, the usual stevens rearrangements didn' t occurred due to the a-enolization of carboxylate and the subsequent O-allcylation. So the stable enamine-type tetrahydroisoquinoline quaternary ammonium base compounds were formed with yields of 90% or more, which were reported for the first time.%1位酯基取代、氮上烷基取代的四氢异喹啉在与碘甲烷成盐后不发生通常的Stevens重排反应,而是酯基α位烯醇化后发生氧烷基化反应,生成了稳定的烯胺型四氢异喹啉季铵碱化合物,收率在90%以上,该类化合物为首次报道.

  18. Ammonium diphosphitoindate(III

    Directory of Open Access Journals (Sweden)

    Farida Hamchaoui

    2013-04-01

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

  19. 季铵盐-高岭石系列插层复合物的制备及结构表征%Preparation and Structural Characterization of Kaolinite Intercalation Compounds with Series of Quaternary Ammonium Salt

    Institute of Scientific and Technical Information of China (English)

    刘钦甫; 王定; 郭鹏; 张帅; 程宏飞; 李晓光; 张士龙

    2015-01-01

    通过多次置换插层反应,以高岭石/甲醇插层复合物为中间体,将不同链长季铵盐分子插入高岭石层间,对其结构、形貌和插层机理进行了探讨。结果表明:季铵盐分子在高岭石层间主要以全反转式构形存在,季铵盐碳链长度对其插层复合体的结构和形貌具有明显控制作用。碳原子数小于8的季铵盐在高岭石层间以单层平卧形式存在,其形成的高岭石插层复合体晶形仍为片状;碳原子数大于等于8的季铵盐在高岭石层间呈石蜡型倾斜双层形式排列,且碳链与高岭石(001)晶面的夹角随碳原子数增大而减小。碳原子数大于等于8的季铵盐进入高岭石层间,将导致高岭石晶层的卷曲,形成纳米卷或管,且随季铵盐碳链长度增加,高岭石片层卷曲程度加深,纳米卷的数量增多。%Kaolinite intercalation compounds with series quaternary ammonium salt prepared through displacement intercalation were characterized.The intercalation mechanism, the arrangement of quaternary ammonium salts between kaolinite layers and the thermal stability and morphology of intercalation complexes were investigated. The results show that the quaternary ammonium salts between kaolinite layers mainly arrange as all-trans configuration, and their carbon chain length has a significant effect on the structure and morphology of intercalation complexes. The quaternary ammonium slats with short carbon chains (i.e., the carbon number was<8) mainly form a monolayer structure in kaolinite interlayer, and the morphology of intercalation complexes remains flat. When the quaternary ammonium salts with relative longer carbon chains (i.e., the carbon number was ³8) mainly arrange in a paraffin-type bilayer structure, the angle between the carbon chain and (001) plane of kaolinite gradually decreases with the increase of the carbon number. In addition, kaolinite platelet beginsto crimp and even develops to

  20. Phase diagram of ammonium nitrate

    Science.gov (United States)

    Dunuwille, M.; Yoo, C. S.

    2014-05-01

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

  1. Phase diagram of ammonium nitrate

    International Nuclear Information System (INIS)

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

  2. Elevated ammonium levels

    DEFF Research Database (Denmark)

    Søgaard, Rikke; Novak, Ivana; MacAulay, Nanna

    2012-01-01

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

  3. QuEChERS-based purification method coupled to ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to determine six quaternary ammonium compounds (QACs) in dairy products.

    Science.gov (United States)

    Xian, Yanping; Dong, Hao; Wu, Yuluan; Guo, Xindong; Hou, Xiangchang; Wang, Bin

    2016-12-01

    QuEChERS-based purification coupled with UPLC-MS/MS method, was developed for six quaternary ammonium compounds (QACs) determination in dairy products. Powder samples were firstly dispersed by water. Protein in liquid milk was precipitated and sample solution was extracted by acetonitrile. QuEChERS-based purification was used to purify the solution. QACs were finally separated by HILIC column and detected in MRM mode of MS/MS under ESI(+). The stable isotope benzyl-2,3,4,5,6-d5-dimethyltetradecylammonium bromide (C14-BAC-d5) was used as an internal standard. This method was validated in terms of linearity, sensitivity, precision, accuracy. Linear relations were favorable for QACs over the selected concentration ranges of 0.2-50μg/L, with correlation coefficients greater than 0.999. The limits of detection (LODs) were in the range of 0.4-14.5μg/kg. Recoveries were between 91.2% and 115% with RSDs of 2.8-7.5% for intra-day precision and 3.7-6.7% for inter-day precision. This validated method was successfully applied to determine the QACs concentrations in dairy products. PMID:27374511

  4. Compostos nitrogenados e carboidratos em sorgo submetido à salinidade e combinações de nitrato e amônio Nitrogenous compounds and carbohydrates in sorghum subjected to salinity and combinations of nitrate and ammonium

    Directory of Open Access Journals (Sweden)

    Ana Karla Moreira Lobo

    2011-06-01

    Full Text Available O objetivo do trabalho foi avaliar os efeitos de combinações de nitrato e amônio no meio, na acumulação de compostos nitrogenados e carboidratos, na presença e ausência de salinidade em plantas de sorgo. Sementes do genótipo CSF 20 foram cultivadas em casa de vegetação, em solução nutritiva com três concentrações de nitrato e amônio (100% NO3-: 0% NH4+, 75% NO3-: 25% NH4+ e 0% NO3-: 100% NH4+, na presença e ausência de salinidade. A salinidade reduziu a concentração de nitrato nas folhas e colmo, nos tratamentos 100:0 e 75:25. O amônio acumulou-se mais nas plantas com NaCl, nas folhas e colmo. Os teores de aminoácidos livres totais nas folhas não se alteraram, mas, no colmo, aumentaram na presença de sal e aumento do amônio. A concentração de prolina livre nas folhas e colmo elevou-se nas plantas sob salinidade. O conteúdo de nitrogênio total foi maior nas folhas, entretanto não houve grandes alterações com a presença do sal. A concentração de carboidratos solúveis totais foi maior nas plantas tratadas com sal, exceto no colmo 0:100. Nas folhas, o teor de sacarose foi reduzido na presença do NaCl e aumento de amônio, enquanto, no colmo, foi maior no tratamento 75:25 com NaCl. O teor de amido não sofreu alterações com as diferentes combinações nas formas de N e salinidade. Conclui-se que combinações de NO-3 e NH4+ no meio afetam a acumulação de compostos nitrogenados e carboidratos em folhas e colmo, com presença ou ausência de salinidade, em plantas de sorgo forrageiro.The objective of this study was to evaluate the effects of combinations of nitrate and ammonium in the medium, on the accumulation of nitrogen compounds and carbohydrates, in the presence and absence of salinity in sorghum plants. CSF 20 genotype sorghum seeds, were grown in the greenhouse and supplied with a nutritive solution at three different concentrations of nitrate and ammonium (100% NO3-: 0% NH4+, 75% NO3-: 25% NH4+ e 0% NO3

  5. Toxicity of Ambient Particulate Matter. III. Acute toxicity study in asthmatic mice following 3-day exposure to ultrafine and fine ammonium nitrate, a model compound for secondary aerosol fraction of PM10

    NARCIS (Netherlands)

    Cassee FR; Dormans JAMA; Loveren H van; Bree L van; Rombout PJA; LEO; LPI

    1998-01-01

    Ammonium nitrate is the most prominent component of secondary PM10 in the Netherlands. In our study, healthy and asthmatic mice were exposed to fine (CMD = 0.3 mum; 4 x 10 exp. 3 particles per cm3) and ultrafine (CMD = 0.03 mum; 2 x 10. exp. 5 particles per cm3) ammonium nitrate. The mean mass conc

  6. Quaternary Ammonium Polyethyleneimine: Antibacterial Activity

    Directory of Open Access Journals (Sweden)

    Ira Yudovin-Farber

    2010-01-01

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

  7. Preparatory of X zeolite (faujasite) with surfactant hexa decyl trimethyl ammonium bromide (HMDTA) for adsorption of organic compounds; Acondicionamiento de zeolita X (faujasita) con surfactante bromuro de hexa decil trimetil amonio (HDTMA) para adsorcion de compuestos organicos

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez R, V

    2003-07-01

    The water represents one of the most valuable natural resources for the alive beings, since it is the essential component of the alive matter. Also, it is fundamental part of our planet, since is an indispensable element for the integral development of the same one. The demographic growth, the human being's activities and the industrial growth, he/she brings as consequence an increase in the use of the water and the generation of residual waters that successively contaminate the hydrological basins, becoming an environmental problem urgent. The contamination of the water with compound such as phenol and benzene, it is a problem that it requires the search of solutions, since it is of compound not very biodegradable, able to accumulate through the food chains and very toxic to the alive beings that they enter in contact with them (Tolgyessy, 1993). In the human beings it can take place damages in liver and kidney, the Agency of Protection to the Atmosphere of the United States (EPA) it considers that the exhibition for benzene is related with the leukemia, it is also considered as a carcinogen substance. Of the methods that are used for the treatment of polluted waters, it highlights the use of adsorber and one of them is the zeolites, since they are broadly used in those separation processes. The zeolites is crystalline aluminosilicates, they are characterized for to have a big superficial area and for their great capacity of exchange cationic, due to it the process of adsorption depends on these two characteristics, since to the modified being superficially for surfactants cationic it originates an enriched layer of carbon organic, which has the capacity to remove pollutants of the water. The present work outlines as objective to carry out the superficial modification of zeolite X using hexa decyl trimethyl ammonium bromide (HMDTA-Br) to different concentrations, with the purpose of making it useful in the removal of pollutants organic, present in watery

  8. Concurrence of Anaerobic Ammonium Oxidation and Organotrophic Denitrification in Presence of p-Cresol.

    Science.gov (United States)

    González-Blanco, G; Cervantes, F J; Beristain-Cardoso, R; Gómez, J

    2015-08-01

    This study was carried out to evaluate the capacity of anaerobic granular sludge for oxidizing ammonium and p-cresol with nitrate as terminal electron acceptor. Kinetics for the anaerobic oxidation of ammonium and p-cresol is described in this paper. The phenolic compound was very efficiently consumed, achieving 65 % of mineralization. Ammonium and nitrate were also consumed at 83 and 92 %, respectively, being the main product N2. Anaerobic ammonium oxidation was promoted owing to accumulation of nitrite, and it allowed the synergy of anaerobic ammonium oxidation and organotrophic denitrification for the simultaneous removal of ammonium, nitrate, and p-cresol. A carbonaceous intermediate partially identified was transiently accumulated, and it transitorily truncated the respiratory process of denitrification. These experimental results might be considered for defining strategies in order to remove nitrate, ammonium, and phenolic compounds from wastewaters. PMID:26062920

  9. X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry characterization of aging effects on the mineral fibers treated with aminopropylsilane and quaternary ammonium compounds

    DEFF Research Database (Denmark)

    Zafar, Ashar; Schjødt-Thomsen, Jan; Sodhi, R.;

    2012-01-01

    X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry were used to investigate the aging effects on the aminopropylsilane (APS) and quaternary ammonium surfactant-treated mineral fibers. APS-coated mineral fiber samples were treated with cationic surfactant and...

  10. Mutagenicity of quaternary ammonium salts containing carbohydrate moieties

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-10-15

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

  11. Simultaneous Determination of Residual Quaternary Ammonium Compounds in Milk by Solid Phase Extraction-High Performance Liquid Chromatography-Tandem Mass Spectrometry%固相萃取-高效液相色谱-串联质谱法同时测定牛奶中多种季铵类化合物残留

    Institute of Scientific and Technical Information of China (English)

    魏瑞成; 李国锋; 高蓉; 孙婷; 龚兰; 陈明; 王冉

    2014-01-01

    A method was proposed for the determination of the residues of the quaternary ammonium compounds ( QACs) in milk by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry ( HPLC-MS/MS ) . The sample was extracted with acetonitrile, cleaned-up by weak cationic exchange solid phase extraction cartridge and concentrated in a gentle nitrogen stream. The separation of 5 QACs was performed on a Thermo C18 column (150 mmí2. 1 mm, 3 μm) using gradient elution of 0. 1%acetic acid and 20 mmol/L ammonium acetate methanol as the mobile phase within 7 min. The QACs were analyzed under the multiple reaction monitoring ( MRM ) mode with positive electrospray ionization. The calibration curves were linear well with correlation coefficient over 0 . 99 . The limit of quantification of the method was 1 . 0 μg/kg for hexadecyltrimethyl ammonium bromide and 0 . 2 μg/kg for benzyldodecyldimethyl ammonium bromide, tetradecyl trimethyl ammonium bromide, benzyldimethyltetradecyl ammonium chloride and didecyldimethyl ammonium bromide. The average recoveries for 5 QACs were between 70. 5% and 96. 6% in pure milk, between 69. 1% and 87. 9% in fresh milk and between 67. 1% and 93. 3% in low fat milk at the spiked levels of 2, 10 and 20 μg/kg, with relative standard derivation ( RSD) from 1. 4% to 11. 6%. The developed method is simple and sensitive, and suitable for rapid analysis of quaternary ammonium compounds in the milk.%建立了快速测定牛奶中季铵类化合物多残留的固相萃取-高效液相色谱-串联质谱法。以乙腈提取目标化合物,弱阳离子固相萃取柱萃取净化,氮吹浓缩处理,C18色谱柱分离,0.1%乙酸-20 mmol/L乙酸铵甲醇溶液梯度洗脱,多反应监测正离子模式扫描。目标化合物在7 min内实现良好分离,并在各自相应浓度范围内线性良好,相关系数>0.99,方法的定量限:十二烷基二甲基苄基溴化铵、十四烷基三甲基溴化铵、十四烷基二甲基苄

  12. The biological activity of quaternary ammonium salts (QASs

    Directory of Open Access Journals (Sweden)

    Ewa Obłąk

    2010-04-01

    Full Text Available Quaternary ammonium salts (QASs, especially those of cationic surfactant character, are applied as antibacterial and antifungal disinfectants. QASs affect lipid-enveloped viruses, including human immunodeficiency virus (HIV and hepatitis B virus (HBV, but not non-enveloped viruses. These compounds are extensively used in domestic (as ingredients of shampoos, hair conditioners, agricultural (as fungicides, pesticides, insecticides, healthcare (as medications, and industrial applications (as biocides, fabric softeners, corrosion inhibitors. The extensive use of quaternary ammonium disinfectants in recent years has led to the development of resistance in microorganisms to these drugs. Thus [i]Staphylococcus[/i] [i]aureus[/i] strains contain the plasmid-carrying genes [i]qacA[/i] and [i]qacB [/i]encoding resistance to quaternary ammonium compounds and acriflavine. The membrane proteins QacA and QacB confer multidrug resistance by exporting the compound by the proton motive force which is generated by the transmembrane electrochemical proton gradient.

  13. The flocculation processing of chitosan quaternary ammonium salt compound flocculant to kaolin suspending liquid%壳聚糖季铵盐复合絮凝剂对高岭土悬浮液的絮凝处理

    Institute of Scientific and Technical Information of China (English)

    王香爱

    2011-01-01

    The chitosan(CTS) was modified using 3- chloro - 2- hydroxypropyl-3-methyl-ammonium chloride (CTA) and the 2-hydroxypropyl-3-methyl-chitosan quaternary ammonium salt (CTA-CTS)was prepared. The chitosan quaternary ammonium salt was combined with the poly aluminum trichloride(PAC) to flocculate the kaolin-containing suspension. The effect of mass ratio of the PAC to CTACTS, the setting time and the pH on the flocculation was studied. The optimum conditions are that the content of CTA-CTS is 2 mg/L, The mass ratio of the PAC to CTA-CTS is 13, the setting time is 22 min,pH is 6. Under these conditions,the turbidity value of the kaolin-containing may drop to 1.0.%以3-氯-2-羟丙基三甲基氯化铵(CTA)对壳聚糖(CTS)进行季铵化改性,制备了壳聚糖季铵盐(CTA-CTS),用其和聚合氯化铝(PAC)复配对高岭土悬浮液进行絮凝处理.考察了复合絮凝剂的质量配比、沉降时间、pH值对絮凝性能的影响.最佳絮凝条件为:壳聚糖季铵盐用量为2 mg/L、m(PAC):m(CTA-CTS)=13、沉降时间为22 min、pH=6,高岭生悬浮液的浊度可降至1.0.

  14. Rotational barriers in ammonium hexachlorometallates as studied by NMR, tunneling spectroscopy and ab initio calculations

    DEFF Research Database (Denmark)

    Birczynski, A.; Lalowicz, Z.T.; Lodziana, Zbigniew

    2004-01-01

    Ammonium hexachlorometallates, (NH4)(2)MCl6 With M = Pd, Pt, Ir, Os, Re, Se, Sn, Te and Pb, comprise a set of compounds with systematically changing properties. The compounds may be ordered according to decreasing tunnelling frequency (TF) of ammonium ions, which is related to the increasing...... structure explain observed variation of the tunnelling frequencies for NH4+. The theory provides also M-Cl distances and barriers for C-2 and C-3 rotations of ammonium ions in respective compounds, which show good agreement with experimental values. (C) 2004 Elsevier B.V. All rights reserved....

  15. Synthesis, characterization, and bioactivity of rosin quaternary ammonium salt derivatives

    Directory of Open Access Journals (Sweden)

    Tao Liang

    2013-02-01

    Full Text Available Two series of rosin quaternary ammonium salts (QAS were synthesized using the same path. The structure of the target products was characterized by HPLC, MS, IR, and 1HNMR, and the bioactivity was determined by filter paper method using Trametes versicolor (white-rot fungus and Gloeophyllum trabeum (brown-rot fungus, which are two kinds of general wood decay fungi in nature. The results showed that all compounds tested had a satisfactory anti-fungal effect at the molarity of 0.025 mmol/mL. Hereinto, acrylpimaric Gemini QAS had better bioactivity than dehydrogenated or tetrahydrogenated rosin QAS against Trametes versicolor. To this fungus, quaternary ammonium groups, which wraps up the membrane of microorganism and disrupts the balance in cell membrane, plays the leading role for its bioactivity. To Gloeophyllum trabeum, the inhibition activity of acrylpimaric QAS and dehydrogenated rosin QAS are almost at the same level and larger than tetrahydrogenated rosin QAS, so we conclude that both quaternary ammonium group and aromatic group play important roles. Compared with dodecyl dimethyl benzyl ammonium chloride (1227, which is a commercially available quaternary ammonium salt type fungicide, acrylpimaric acid quaternary ammonium salts have approximate bioactivity against Gloeophyllum trabeum. In conclusion, rosin derivatives with functional groups would do well in wood preservative applications.

  16. Aqueous Media Oxidation of Alcohols with Ammonium Persulfate

    Institute of Scientific and Technical Information of China (English)

    IMANZADEH, Gholam Hassan; ZAMANLOO, Mohammad R.; MANSOORI, Yaghoob; KHODAYARI, Ali

    2007-01-01

    Oxidation of series of various primary and secondary alcohols to corresponding carbonyl compounds with ammonium persulfate in aqueous media was described. No over oxidation of primary alcohols to carboxylic acids and secondary alcohols to esters was observed. Under such conditions benzoin was converted to benzoic acid.

  17. New synthetic method and properties of ammonium dinitramide (ADN)

    Energy Technology Data Exchange (ETDEWEB)

    Hatano, H.; Onda, T.; Shi Ino, K.; Kiname, S.I. [Technical Center, Hosoya Kako, Osawa (Japan); Miyazaki, S.; Suzuki, S. [Research et Development Center, Nissan Motor Co, Saitama (Japan)

    1996-12-31

    Ammonium dinitramide (ADN) is one of the energetic materials, its hazard, however, has never been presented yet. In this paper, new synthetic method of ADN and its properties are contained. It has been found out that ADN has little hazard and is a safe energetic compound. (authors) 4 refs.

  18. Synthesis, micellisation and interaction of novel quaternary ammonium compounds derived from l-Phenylalanine with 1,2-dipalmitoyl-sn-glycero-3-phosphocholine as model membrane in relation to their antibacterial activity, and their selectivity over human red blood cells.

    Science.gov (United States)

    Joondan, Nausheen; Caumul, Prakashanand; Akerman, Matthew; Jhaumeer-Laulloo, Sabina

    2015-02-01

    A series of quaternary ammonium compounds (QUATS) derived from l-Phenylalanine have been synthesized and their antibacterial efficiencies were determined against various strains of Gram-positive and Gram-negative bacteria. The antibacterial activity increased with increasing chain length, exhibiting a cut-off effect at C14 for Gram-positive and C12 for Gram-negative bacteria. The l-Phenylalanine QUATS displayed enhanced antibacterial properties with a higher cut-off point compared to their corresponding l-Phenylalanine ester hydrochlorides. The CMC was correlated with the MIC, inferring that micellar activity contributes to the cut-off effect in antibacterial activity. The hemolytic activities (HC50) of the QUATS against human red blood cells were also determined to illustrate the selectivity of these QUATS for bacterial over mammalian cells. In general, the MIC was lower than the HC50, and assessment of the micellar contribution to the antibacterial and hemolytic evaluation in TBS as a common medium confirmed that these QUATS can act as antibacterial, yet non-toxic molecules at their monomer concentrations. The interaction of the QUATS with the phospholipid vesicles (1,2-dipalmitoyl-sn-glycero-3-phosphocholine, DPPC) in the presence of 1-anilino-8-naphthalene sulfonate (ANS) and 1,6-diphenyl-1,3,5-hexatriene (DPH) as fluorescence probes showed that the presence of the quaternary ammonium moiety causes an increase in hydrophobic interactions, thus causing an increase in antibacterial activity.

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

    Directory of Open Access Journals (Sweden)

    Andreas Späth

    2010-04-01

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

  20. Tripropyl­ammonium trithio­cyanurate

    OpenAIRE

    Yang, Yunxia

    2010-01-01

    In the title compound (systematic name: tripropyl­azanium 2,4,6-tris­ulfanyl­idene­cyclo­hexan-1-ide), (C3H7)3HN+·C3H2N3S3 −, one H atom of trithio­cyanuric acid is accepted by tripropyl­amine to form the ammonium ion. Coplanar trithio­cyanurate and tripropyl­ammonium ions [dihedral angle = 82.33 (8)°] form the salt, which is stabilised by various N—H⋯S and N—H⋯N contacts.

  1. Tripropyl­ammonium trithio­cyanurate

    Science.gov (United States)

    Yang, Yunxia

    2010-01-01

    In the title compound (systematic name: tripropyl­azanium 2,4,6-tris­ulfanyl­idene­cyclo­hexan-1-ide), (C3H7)3HN+·C3H2N3S3 −, one H atom of trithio­cyanuric acid is accepted by tripropyl­amine to form the ammonium ion. Coplanar trithio­cyanurate and tripropyl­ammonium ions [dihedral angle = 82.33 (8)°] form the salt, which is stabilised by various N—H⋯S and N—H⋯N contacts. PMID:21588990

  2. Solubility of the Sodium and Ammonium Salts of Oxalic Acid in Water with Ammonium Sulfate.

    Science.gov (United States)

    Buttke, Lukas G; Schueller, Justin R; Pearson, Christian S; Beyer, Keith D

    2016-08-18

    The solubility of the sodium and ammonium salts of oxalic acid in water with ammonium sulfate present has been studied using differential scanning calorimetry, X-ray crystallography, and infrared spectroscopy. The crystals that form from aqueous mixtures of ammonium sulfate/sodium hydrogen oxalate were determined to be sodium hydrogen oxalate monohydrate under low ammonium sulfate conditions and ammonium hydrogen oxalate hemihydrate under high ammonium sulfate conditions. Crystals from aqueous mixtures of ammonium sulfate/sodium oxalate were determined to be ammonium oxalate monohydrate under moderate to high ammonium sulfate concentrations and sodium oxalate under low ammonium sulfate concentrations. It was also found that ammonium sulfate enhances the solubility of the sodium oxalate salts (salting in effect) and decreases the solubility of the ammonium oxalate salts (salting out effect). In addition, a partial phase diagram for the ammonium hydrogen oxalate/water system was determined. PMID:27482644

  3. Comparative DFT study of crystalline ammonium perchlorate and ammonium dinitramide.

    Science.gov (United States)

    Zhu, Weihua; Wei, Tao; Zhu, Wei; Xiao, Heming

    2008-05-22

    The electronic structure, vibrational properties, absorption spectra, and thermodynamic properties of crystalline ammonium perchlorate (AP) and ammonium dinitramide (ADN) have been comparatively studied using density functional theory in the local density approximation. The results shows that the p states for the two solids play a very important role in their chemical reaction. From the low frequency to high frequency region, ADN has more motion modes for the vibrational frequencies than AP. The absorption spectra of AP and ADN display a few, strong bands in the fundamental absorption region. The thermodynamic properties show that ADN is easier to decompose than AP as the temperature increases. PMID:18396853

  4. Synthesis and Characterization of Two Novel Organic-Inorganic Compounds Based on Tetrahexyl and Tetraheptyl Ammonium Ions and the Preyssler Anion and Their Catalytic Activities in the Synthesis of 4-Aminopyrazolo[3,4-d]- Pyrimidines

    Directory of Open Access Journals (Sweden)

    Fatemeh Farrash Bamoharram

    2010-04-01

    Full Text Available Two novel organic–inorganic compounds based on tetrahexylammonium (THA and tetraheptylammonium (THPA ions and the Preyssler anion, [NaP5W30O110]14-, were synthesized and formulated as (THA7.7H6.3 [NaP5W30O110] (A and (THPA7.5 H6.5[N aP5W30O110] (B. The synthesized compounds were characterized by IR, UV, and TGA and used for the catalytic synthesis of 4-aminopyrazolo[3,4,-d]pyrimidine derivatives 2a-2d. Our findings showed efficient catalytic activities for A and B.

  5. Volatile Corrosion Inhibitors Part III- Ammonium stearate and M-Dinitrobenezene

    Directory of Open Access Journals (Sweden)

    K. S. Rajagopalan

    1962-07-01

    Full Text Available In earlier studies while screening various chemical compound for their vapour phase inhibiting properties. Some ammonium salts and nitro-compounds had shown promising results. Of these, ammonium stearate and m-dinitrobenzene gave the best results in accelerated short term tests. In the present paper a more detailed investigation on the corrosion protection given by them has been made.Ammonium stearate and m-dinitrobenzene, both, have been found to perform satisfactorily under all test conditions except SOsub2 test where m-dinitrobenzene failed. Their indigenous availability, low cost and good corrosion inhibiting properties demands favorable consideration for their adoption as VCIs for general use.

  6. Quaternary Ammonium Polyethyleneimine: Antibacterial Activity Ira

    International Nuclear Information System (INIS)

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

  7. Ammonium nitrate: a promising rocket propellant oxidizer

    Science.gov (United States)

    Oommen; Jain

    1999-06-30

    Ammonium nitrate (AN) is extensively used in the area of fertilizers and explosives. It is present as the major component in most industrial explosives. Its use as an oxidizer in the area of propellants, however, is not as extensive as in explosive compositions or gas generators. With the growing demand for environmental friendly chlorine free propellants, many attempts have been made of late to investigate oxidizers producing innocuous combustion products. AN, unlike the widely used ammonium perchlorate, produces completely ecofriendly smokeless products. Besides, it is one of the cheapest and easily available compounds. However, its use in large rocket motors is restricted due to some of its adverse characteristics like hygroscopicity, near room temperature phase transformation involving a volume change, and low burning rate (BR) and energetics. The review is an attempt to consolidate the information available on the various issues pertaining to its use as a solid propellant oxidizer. Detailed discussions on the aspects relating to phase modifications, decomposition chemistry, and BR and energetics of AN-based propellants, are presented. To make the review more comprehensive brief descriptions of the history, manufacture, safety, physical and chemical properties and various other applications of the salt are also included. Copyright 1999 Elsevier Science B.V.

  8. Ammonium 4-methoxybenzenesulfonate

    Directory of Open Access Journals (Sweden)

    Sebastián Suarez

    2012-07-01

    Full Text Available The molecular structure of the title compound, NH4+·C7H7O4S−, is featureless [the methoxy C atom deviating 0.173 (6 Å from the phenyl mean plane] with interatomic distances and angles in the expected ranges. The main feature of interest is the packing mode. Hydrophilic (SO3 and NH4 and hydrophobic (PhOCH3 parts in the structure segregate, the former interacting through a dense hydrogen-bonding scheme, leading to a well connected two-dimensional structure parallel to (100 and the latter hydrophobic groups acting as spacers for an interplanar separation of c/2 = 10.205 (2 Å. In spite of being aligned along [110], the benzene rings stack in a far from parallel fashion [viz. consecutive ring centers determine a broken line with a 164.72 (12° zigzag angle], thus preventing any possible π–π interaction.

  9. Preparation of nanodispersed titania using stabilized ammonium nitrate melts

    KAUST Repository

    Raciulete, Monica

    2010-10-01

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

  10. 21 CFR 582.1141 - Ammonium phosphate.

    Science.gov (United States)

    2010-04-01

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

  11. 高效液相色谱-串联质谱法测定樱桃番茄中四种季铵类农药%Simultaneous determination of quaternary ammonium compounds in tomato by liquid chromatography-tandem mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    张曦; 金芬; 钱永忠; 于志勇; 王静

    2011-01-01

    A method for the simultaneously determination of four representative quaternary ammonium compounds [ chlormequat (CQ) chloride, mepiquat(MQ) chloride, deiquat (DQ) dibromide hydrate and difenzoquat (DF) methyl sulfate] ,using liquid chromatography-tandem mass spectrometry(LC-MS/MS) system was developed. The chromatographic separation was performed using a hydrophilic interaction liquid chromatography(HILIC) column to avoid LC-MS system contamination with the use of ion-pair reagents. Aqueous solution containing 0.1 % formic acid (A) and acetonitrile(B) ( 75:25, V/V) were used as the mobile phasegavegood chromatographic retention and sensitivity for these four quaternary ammonium compounds(QACs).The recovery was 91.4%~106.3% for the four QACs at three concentration levels. The limit of quantitation (LOQ)for the four QACs in tomato samples were 0.005mg/kg based on the lowest spiked concentration with suitable precision and accuracy. Finally, the method was successfully used to detect residual QACs in cherry-tomatoes.%建立了4种季铵类农药(矮壮素、燕麦枯、敌草快和缩节胺)的高效液相色谱-串联质谱(LC-MS/MS)检测方法.样品用75%乙腈-水溶液提取,高速离心后取上清液过尼龙滤膜,用亲水柱分离,以含0.1%甲酸的水:乙腈=25:75(V:V)作为流动相,在正离子多反应监测(MRM)模式下进行测定.4种季铵类农药的线性范围为0.5~100ng/mL,线性相关系数在0.9982~0.9996范围内,方法检出限为0.005mg/kg,可以满足国际限量的要求.在0.04、0.08、0.16mg/kg添加浓度下,4种季铵类农药的回收率为91.4%~106.3%,相对标准偏差(RSD)小于15%.本方法可用于樱桃番茄样品中4种季铵类农药的测定.

  12. 77 FR 50613 - Didecyl Dimethyl Ammonium Carbonate and Didecyl Dimethyl Ammonium Bicarbonate; Exemption From the...

    Science.gov (United States)

    2012-08-22

    ... AGENCY 40 CFR Part 180 Didecyl Dimethyl Ammonium Carbonate and Didecyl Dimethyl Ammonium Bicarbonate... Didecyl Dimethyl Ammonium Carbonate and Didecyl Dimethyl Ammonium Bicarbonate, jointly referred to as.... Background and Statutory Findings In the Federal Register of December 8, 2011 (76 FR 76674) (FRL-...

  13. Synthesis and characterization of ammonium phosphate fertilizers with boron

    OpenAIRE

    ANGELA MAGDA; RODICA PODE; CORNELIA MUNTEAN; MIHAI MEDELEANU; ALEXANDRU POPA

    2010-01-01

    The concentration of boron, an essential micronutrient for plants, presents a narrow range between deficiency and toxicity. In order to provide the boron requirement for plants, and to avoid toxicity problems, boron compounds are mixed with basic fertilizers. Sodium borate pentahydrate was used as a boron source. Ammonium orthophosphates fertilizers with boron were prepared by neutralizing phosphoric acid with ammonia and addition of variable amounts of sodium tetraborate pentahydrate to the ...

  14. Time-resolved X-ray absorption spectroscopy for the study of solid state reactions: synthesis of nanocrystalline barium titanate and thermal decomposition of ammonium hexachlorometallate compounds; Zeitaufgeloeste Roentgenabsorptionspektroskopie zur Untersuchung von Festkoerperreaktionen: Synthese von nanokristallinem Bariumtitanat und thermische Zersetzung von Ammoniumhexachlorometallat-Verbindungen

    Energy Technology Data Exchange (ETDEWEB)

    Rumpf, H.

    2001-07-01

    This report presents investigations on the mechanism of two different types of solid-state reactions: At first, barium titanate nanopowders were prepared through a combined polymerization and pyrolysis of a metallo-organic precursor. The mean particle size d{sub m} could be adjusted by choosing appropriate reaction temperatures and tempering atmospheres. In the present in situ study of this particular solid-phase reaction, X-ray absorption near edge structure (XANES) spectroscopy at the Ti K and Ba L{sub 3}-edges was applied in the preparation route of BaTiO{sub 3} nanopowders. A pronounced distortion of the lattice symmetry was found to occur in very fine BaTiO{sub 3} nanopowders (d{sub m} < 20 nm). Secondly, in situ XANES investigations were carried out at the Cl K, Pd L{sub 3}, Rh L{sub 3}, and Pt L{sub 3}-edges to study the mechanism of the thermal decomposition of ammonium hexachlorometallates. The results exceed structural information obtained by in situ X-ray diffraction methods and thermal analysis. Feff8 multiple scattering simulations have been carried out to disclose new intermediate phases of unknown reference compounds. (orig.)

  15. Synthesis of quarternary ammonium salts with dithiocarbamate moiety and their antifungal activities against Helminthosporium oryzae

    Indian Academy of Sciences (India)

    Mandeep Singh; Anita Garg; Anjali Sidhu; Vineet Kumar

    2013-05-01

    Quaternary ammonium salts containing dithiocarbamate moiety were synthesized and evaluated for their antifungal activities against Helminthosporium oryzae. All the synthesized compounds showed moderate to promising fungitoxicity against the test. Some of the synthesized compounds inflicted antifungal activity greater than the standard fungicide.

  16. Synthesis of Chitosan Quaternary Ammonium Salts

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A series of N-alkyl or N-aryl chitosan quaternary ammonium salts were prepared via Schiffs base intermediates. Quaternization of N-substituted chitosan derivatives was carried out using methyl iodide to produce water-soluble cationic chitosan quaternary ammonium salt. The products were characterized by IR, 1HNMR and elemental analysis. The degree of substitution of chitosan quaternary ammonium salt was calculated by elemental analysis.

  17. Synthesis, antimicrobial activity of lamotrigine and its ammonium derivatives

    Indian Academy of Sciences (India)

    Yong Qian; Peng-Cheng Lv; Lei Shi; Rui-Qin Fang; Zhong-Cheng Song; Hai-Liang Zhu

    2009-07-01

    Antiepileptic drug lamotrigine and its thirteen ammonium salt complexes (4a-4m) were synthesized and characterized by IR, elemental analysis, 1H-NMR, and MS spectral methods. Many of the ammonium salts (4a-4m) were first reported. Furthermore, the crystal structure of compound 3 was determined by single crystal X-ray diffraction analysis. All these complexes were tested in vitro for their antibacterial activity (Bacillus subtilis, Staphylococcus aureus, Enterococus faecalis, Escherichia coli, Pseudomonas aeruginosa and Enterobacter cloacae). The results indicated that most of the complexes showed good antibacterial activity against Gram-positive (B. subtilis, S. aureus and S. faecalis), but showed mild, even inactive against Gram-negative bacterial strains.

  18. 33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

    Science.gov (United States)

    2010-07-01

    ... nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126..., ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. (a) When any item of ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo...

  19. Ammonium-induced inhibition of ammonium-starved Nitrosomonas europaea cells in soil and sand slurries

    NARCIS (Netherlands)

    Gerards, S.; Duyts, H.; Laanbroek, H.J.

    1998-01-01

    Ammonia-oxidising bacteria are poor competitors for limiting amounts of ammonium. Hence, starvation for ammonium seems to be the regular condition for these bacteria in natural environments. Long-term survival in the absence of ammonium will be dependent on the ability to maintain large population s

  20. The Effect of the Ammonium Group on the Different Annealing Processes

    International Nuclear Information System (INIS)

    The ammonium group can play an essential role in the different annealing processes of neutron-irradiated ammonium compounds. Some details of this effect were investigated. To give a more complete picture of this subject first some typical results, already published, are briefly discussed, concerning the thermal, radiation, photochemical and ultra-sonic annealing of ammonium and potassium sulphate as well as of ammonium and potassium dichromate. Afterwards new experimental data are reported showing the influence of the ammonium group on the thermal, radiation and ultra-sonic annealing of mono-, di- and triammonium phosphates. It was established that under the conditions of neutron irradiation in the pile the ammonium group in a compound can be transformed into certain metastabile recoil fragments, which can lead to the formation of reducing substances, e. g. hydrazine. The yield of hydrazine increases by the subsequent treatment of the neutron-irradiated solid samples with gamma-rays, ultra sound etc. Simultaneously with the increase in the hydrazine yield a strong change of the retention occurs. (author)

  1. Atmospheric behaviour of ammonia and ammonium.

    NARCIS (Netherlands)

    Asman, W.A.J.

    1987-01-01

    1.4.1 Scope of this thesisA few models for ammonia and ammonium exist. Russell et al. (1983) made a multi-layer Lagrangian transport model describing the transport and formation of ammonium nitrate aerosol for California. They did not take reactions of ammonia and sulphuric acid into account, nor we

  2. Ammonium derivatives of chromenones and quinolinones as lead antimicrobial agents

    Indian Academy of Sciences (India)

    Shilpi Gupta; Seema Singh; Abha Kathuria; Manish Kumar; Sweta Sharma; Ram Kumar; Virinder S Parmar; Bharat Singh; Anjali Gupta; Erik Van Der Eycken; Gainda L Sharma; Sunil K Sharma

    2012-03-01

    A series of novel ammonium derivatives were synthesized and examined for their antimicrobial efficacy. Comparison of antimicrobial spectrum revealed that compounds 9, 11, 16 and 23 had strong potential against pathogens in vitro. Cytotoxicity results showed compound 9 to be least toxic, it is non-toxic to A549 and U87 cells in MTT assay and exhibits marginal toxicity (15-20%) to human erythrocytes at a concentration of 1000 g/ml as compared to 100% lysis of cells by 31.25 g/ml of the standard drug amphotericin B. This compound has MIC values in the range of 1.95-31.25 g/disc in DDA against different pathogens and may considered to be an important lead antimicrobial molecule for further exploration.

  3. 49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

    Science.gov (United States)

    2010-10-01

    ... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as... Captain of the Port (COTP). (1) Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more...

  4. Ammonium and attachment of Rhodopirellula baltica.

    Science.gov (United States)

    Frank, Carsten S; Langhammer, Philipp; Fuchs, Bernhard Maximilian; Harder, Jens

    2011-05-01

    A dimorphic life cycle has been described for the planctomycete Rhodopirellula baltica SH1(T), with juvenile motile, free-swimming cells and adult sessile, attached-living cells. However, attachment as a response to environmental factors was not investigated. We studied the response of R. baltica to nitrogen limitation. In batch cultures, ammonium limitation coincided with a dominance of free-swimming cells and a low number of aggregates. Flow cytometry revealed a quantitative shift with increasing ammonium availability, from single cells towards attached cells in large aggregates. During growth of R. baltica on glucose and ammonium in chemostats, an ammonium addition caused a macroscopic change of the growth behaviour, from homogeneous growth in the liquid phase to a biofilm on the borosilicate glass wall of the chemostat vessel. Thus, an ammonium limitation-a carbon to nitrogen supply ratio of 30:1-sustained free-living growth without aggregate formation. A sudden increase in ammonium supply induced sessile growth of R. baltica. These observations reveal a response of Rhodopirellula baltica cells to ammonium: they abandon the free-swimming life, attach to particles and form biofilms. PMID:21340506

  5. THE SURFACE PHOTOCHEMISTRY OF PROCYMIDONE IN PRESENCE OF AMMONIUM FERRIC CITRATE

    Directory of Open Access Journals (Sweden)

    Ivan Osipov

    2015-12-01

    Full Text Available Procymidone was chosen as the model compound and its phototransformation was followed under sunlight irradiation. The main photodegradation products on silica is 3,5-dichloroaniline and 3,5-diclorphenilisocyanate. The use of ammonium ferric citrate enhances the degradation of the procymidone.

  6. Different virucidal activities of hyperbranched quaternary ammonium coatings on poliovirus and influenza virus

    NARCIS (Netherlands)

    Tuladhar, E.; Koning, de M.C.; Fundeanu, I.; Beumer, R.R.; Duizer, E.

    2012-01-01

    Virucidal activity of immobilized quaternary ammonium compounds (IQACs) coated onto glass and plastic surfaces was tested against enveloped influenza A (H1N1) virus and nonenveloped poliovirus Sabin1. The IQACs tested were virucidal against the influenza virus within 2 min, but no virucidal effect a

  7. Superoxide Anion Radical Scavenging Ability of Quaternary Ammonium Salt of Chitosan

    Institute of Scientific and Technical Information of China (English)

    Xiao Yan ZHU; Jian Min WU; Zhi Shen JIA

    2004-01-01

    A series of N-alkyl or N-aryl chitosan quaternary ammonium salt were prepared using 96% deacetylated chitosan. Their scavenging activities against superoxide anion radical were investigated by chemiluminescence. The IC50 values of these compounds range from 280 to 880 μg/mL, which should be attributed to their different substitutes.

  8. Natural Nitrogen—15 Abundance of Ammonium Nitrogen and Fixed Ammonium in Soils

    Institute of Scientific and Technical Information of China (English)

    SHISHU-LIAN; XINGGUANG-XI; 等

    1992-01-01

    The present article deals with the natural nitrogen-15 abundance of ammonium nitrogen and fixed ammonium in different soils.Variations in the natural 15N abundance of ammonium nitrogen mineralized in soils under anaerobic incubation condition were related to soil pH.The δ 15N of mineralizable N in acid soils was lower but that in neutral and calcareous soils was higher compared with the δ 15N of total N in the soils.A variation tendence was also found in the δ 15N of amino-acid N in the hydrolysates of soils.The natural 15N abundance of fixed ammonium was higher than that of total N in most surface soils and other soil horizons,indicating that the increase of δ 15N in the soil borizons beneath subsurface horizon of some forest soils and acid paddy soils was related to the higher δ 15N value of fixed ammonium in the soil.

  9. Benchmark binding energies of ammonium and alkyl-ammonium ions interacting with water. Are ammonium-water hydrogen bonds strong?

    Science.gov (United States)

    Vallet, Valérie; Masella, Michel

    2015-01-01

    Alkyl-ammonium ion/water interactions are investigated using high level quantum computations, yielding thermodynamics data in good agreement with gas-phase experiments. Alkylation and hydration lead to weaken the NHsbnd O hydrogen bonds. Upon complete hydration by four water molecules, their main features are close to those of the OHsbnd O bond in the isolated water dimer. Energy decomposition analyses indicate that hydration of alkyl-ammonium ions are mainly due to electrostatic/polarization effects, as for hard monoatomic cations, but with a larger effect of dispersion.

  10. Preparation of uranium dioxide by thermal decomposition and direct reduction of ammonium uranate

    International Nuclear Information System (INIS)

    The thermal decomposition of ammonium uranate has been studied by infrared spectroscopy, and X-ray diffraction. It has been show that ammonia remains in the solid until substantially 350 Centigrade degrees, when gaseous nitrogen is released. It is concluded that compounds derived from the calcination of ammonium uranate at atmospheric pressure, produced amorphous U O3 at about 350-400 Centigrade degrees and transform to U3 O8 via α - U O3 and/or α - U O3. The object of this study was to obtain reliable fundamental information regarding the character of the pure carbon monoxide-ammonium uranate-uranium trioxide-uranium octaoxide reaction, in the range of temperatures that has been used in commercial reduction processes. Through the use of high-purity samples and by the proper control of incidental variable, this object was realized. (Author)

  11. Reduction in Ammonium Ions in Sludge Liquor

    Directory of Open Access Journals (Sweden)

    Eglė Šlajūtė

    2013-12-01

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

  12. N-Chlorotaurine and ammonium chloride: an antiseptic preparation with strong bactericidal activity.

    Science.gov (United States)

    Gottardi, Waldemar; Arnitz, Roland; Nagl, Markus

    2007-04-20

    The bactericidal activity of the endogenous antiseptic N-chlorotaurine (NCT) is significantly enhanced in the presence of ammonium chloride which induces the formation of monochloramine (NH(2)Cl) whose strong bactericidal activity is well known. In this study the properties of NCT plus ammonium chloride have been investigated. The reaction of active chlorine compounds like chloramine-T (N-chlorotoluene-sulfonamide sodium), chloroisocyanuric acid derivatives, hypochlorites (NaOCl, CaOCl(2)) with ammonium chloride did not stop at the stage of monochloramine, and the pungent smelling by-products di- and trichloramine, NHCl(2) and NCl(3), were also formed. This was not the case with NCT where only monochloramine was generated. The equilibrium constant of the reaction of NCT with ammonium was found to be [Formula: see text] , which allows to estimate the equilibrium concentration of monochloramine in aqueous solutions of NCT and ammonium chloride. At concentrations each ranging between 0.01% and 1.0% it comes to [NH(2)Cl]=3.5-254 ppm. As an unexpected result the monochloramine containing formulation turned out to be most stable in plain water without buffer additives. Quantitative killing assays revealed complete inactivation of 10(6) to 10(7)CFU/mL of seven bacterial strains by 0.1% NCT plus 0.1% ammonium chloride within 5 min, while with plain 0.1% NCT an incubation time of 2-4h was needed to achieve the same effect. The highly significant increase of bactericidal activity (200-300-fold) could be assigned to the presence of monochloramine which could be isolated by vacuum distillation. Aqueous solutions of NCT and ammonium chloride provide a highly effective and well tolerable antiseptic preparation appropriate to a treatment cycle of at least 1 month if stored in the refrigerator.

  13. An 15N study of the effects of nitrate, ammonium, and nitrate + ammonium nutrition on nitrogen assimilation in Zea mays L

    International Nuclear Information System (INIS)

    A brief review of the literature on the effects of nitrate and ammonium nitrogen sources on plant growth, and the assimilation of those nitrogen sources, has been presented. It was concluded that ammonium nutrition produces optimum growth, with nitrate + ammonium being a better nitrogen source than only nitrate. Leaf blade nitrate reductase activity exceeded that of the root in nitrate-fed plants, suggesting that the shoot is the major region of nitrate assimilation. This is further supported by the results of xylem exudate analysis, where 93% of the newly-absorbed nitrogen exported by the roots was detected as nitrate. Evidence in support of this hypothesis was also obtained by studying the distribution of 15N in the various nitrogenous compounds. The effects of nitrogen source on plant growth, organic nitrogen and inorganic nitrogen contents, and the rates of incorporation into nitrogenous compounds were studied. The observed differences were explained with reference to the effects of the various nitrogen sources on the physiology of the plants. The experimental techniques included assays of the enzymes nitrate reductase and glutamine synthetase, whole plant growth studies, and the analysis of nitrogenous compounds of xylem exudate and those extracted from the leaf blade, leaf base, and root regions of maize plants after feeding with a nutrient solution containing nitrogen as 15N

  14. Occupational Exposure in Ammonium Phosphate Fertilizer Plants

    International Nuclear Information System (INIS)

    Occupational exposures and activity concentrations have been assessed in two industrial plants producing mono-ammonium phosphate and di-ammonium phosphate fertilizers, located in south-western Spain. The annual effective doses received by the workers are below 1 mSv/a, with the contribution from external exposure being similar to that from internal exposure. The dose contribution from inhalation of dust has been estimated to be about 0.12 mSv/a, while the 222Rn concentrations inside the plants are of no concern. Consequently, no additional radiation protection measures need to be taken to protect the workers in these facilities. (author)

  15. Main Factors Effecting Anaerobic Ammonium Oxidation

    Institute of Scientific and Technical Information of China (English)

    YANG Xiao-fei

    2014-01-01

    Anaerobic Ammonium Oxidation (ANAMMOX) drew more attentions because of its denitrification in wastewater with low carbon resource. The external conditions of ANAMMOX are relatively harsh,however this reaction does not require the participation of oxygen and organics. So the research and technology development of ANAMMOX has the significance of sustainable development.In this paper, the main influencing factors of ANAMMOX were summarized,Combined with recent research status of ANAMMOX technology, the development trend of the anaerobic ammonium oxidation technology was prospected.

  16. On the evaporation of ammonium sulfate solution

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-07-16

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

  17. On the evaporation of ammonium sulfate solution.

    Science.gov (United States)

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

    2009-11-10

    Aqueous evaporation and condensation kinetics are poorly understood, and uncertainties in their rates affect predictions of cloud behavior and therefore climate. We measured the cooling rate of 3 M ammonium sulfate droplets undergoing free evaporation via Raman thermometry. Analysis of the measurements yields a value of 0.58 +/- 0.05 for the evaporation coefficient, identical to that previously determined for pure water. These results imply that subsaturated aqueous ammonium sulfate, which is the most abundant inorganic component of atmospheric aerosol, does not affect the vapor-liquid exchange mechanism for cloud droplets, despite reducing the saturation vapor pressure of water significantly. PMID:19861551

  18. Alternative process to produce UF{sub 4} using the effluent from ammonium uranyl carbonate route

    Energy Technology Data Exchange (ETDEWEB)

    Silva Neto, Joao B.; Garcia, Rafael Henrique Lazzari; Dal Vechio, Edvaldo, E-mail: jbsneto@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), SP (Brazil); Riella, Humberto G., E-mail: riella@enq.ufsc.br [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil); Instituto Nacional de Ciencias e Tecnologia de Reatores Nucleares Inovadores (INCT/CNPq) (Brazil); Carvalho, Elita F. Urano de; Durazzo, Michelangelo [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), SP (Brazil); Instituto Nacional de Ciencias e Tecnologia de Reatores Nucleares Inovadores (INCT/CNPq) (Brazil)

    2011-07-01

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

  19. Understanding the impact of the central atom on the ionic liquid behavior: phosphonium vs ammonium cations.

    Science.gov (United States)

    Carvalho, Pedro J; Ventura, Sónia P M; Batista, Marta L S; Schröder, Bernd; Gonçalves, Fernando; Esperança, José; Mutelet, Fabrice; Coutinho, João A P

    2014-02-14

    The influence of the cation's central atom in the behavior of pairs of ammonium- and phosphonium-based ionic liquids was investigated through the measurement of densities, viscosities, melting temperatures, activity coefficients at infinite dilution, refractive indices, and toxicity against Vibrio fischeri. All the properties investigated are affected by the cation's central atom nature, with ammonium-based ionic liquids presenting higher densities, viscosities, melting temperatures, and enthalpies. Activity coefficients at infinite dilution show the ammonium-based ionic liquids to present slightly higher infinite dilution activity coefficients for non-polar solvents, becoming slightly lower for polar solvents, suggesting that the ammonium-based ionic liquids present somewhat higher polarities. In good agreement these compounds present lower toxicities than the phosphonium congeners. To explain this behavior quantum chemical gas phase DFT calculations were performed on isolated ion pairs at the BP-TZVP level of theory. Electronic density results were used to derive electrostatic potentials of the identified minimum conformers. Electrostatic potential-derived CHelpG and Natural Population Analysis charges show the P atom of the tetraalkylphosphonium-based ionic liquids cation to be more positively charged than the N atom in the tetraalkylammonium-based analogous IL cation, and a noticeable charge delocalization occurring in the tetraalkylammonium cation, when compared with the respective phosphonium congener. It is argued that this charge delocalization is responsible for the enhanced polarity observed on the ammonium based ionic liquids explaining the changes in the thermophysical properties observed. PMID:24527930

  20. Understanding the impact of the central atom on the ionic liquid behavior: Phosphonium vs ammonium cations

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Pedro J.; Ventura, Sónia P. M.; Batista, Marta L. S.; Schröder, Bernd; Coutinho, João A. P., E-mail: jcoutinho@ua.pt [CICECO, Departamento de Química, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Gonçalves, Fernando [Departamento de Biologia e CESAM (Centro de Estudos do Ambiente e do Mar), Universidade de Aveiro, 3810-193 Aveiro (Portugal); Esperança, José [Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, 2780-901 Oeiras (Portugal); Mutelet, Fabrice [Laboratoire Réactions et Génie des Procédés, CNRS (UPR3349), Nancy-Université, 1 rue Grandville, BP 20451 54001 Nancy (France)

    2014-02-14

    The influence of the cation's central atom in the behavior of pairs of ammonium- and phosphonium-based ionic liquids was investigated through the measurement of densities, viscosities, melting temperatures, activity coefficients at infinite dilution, refractive indices, and toxicity against Vibrio fischeri. All the properties investigated are affected by the cation's central atom nature, with ammonium-based ionic liquids presenting higher densities, viscosities, melting temperatures, and enthalpies. Activity coefficients at infinite dilution show the ammonium-based ionic liquids to present slightly higher infinite dilution activity coefficients for non-polar solvents, becoming slightly lower for polar solvents, suggesting that the ammonium-based ionic liquids present somewhat higher polarities. In good agreement these compounds present lower toxicities than the phosphonium congeners. To explain this behavior quantum chemical gas phase DFT calculations were performed on isolated ion pairs at the BP-TZVP level of theory. Electronic density results were used to derive electrostatic potentials of the identified minimum conformers. Electrostatic potential-derived CHelpG and Natural Population Analysis charges show the P atom of the tetraalkylphosphonium-based ionic liquids cation to be more positively charged than the N atom in the tetraalkylammonium-based analogous IL cation, and a noticeable charge delocalization occurring in the tetraalkylammonium cation, when compared with the respective phosphonium congener. It is argued that this charge delocalization is responsible for the enhanced polarity observed on the ammonium based ionic liquids explaining the changes in the thermophysical properties observed.

  1. Characteristics of simultaneous ammonium and phosphate adsorption from hydrolysis urine onto natural loess.

    Science.gov (United States)

    Jiang, Shanqing; Wang, Xiaochang; Yang, Shengjiong; Shi, Honglei

    2016-02-01

    Nutrient recovery from human urine is a promising pretreatment of domestic wastewater and provides a sustainable recyclability of N and P. In this study, batch experiments were conducted to identify the characteristics of natural loess (NL) for the adsorption and recovery of ammonium and phosphate from hydrolysis urine (HU). The adsorption mechanisms, the adsorption kinetics and isotherms, as well as the major influencing factors, such as pH and temperature, were investigated. Results revealed that adsorption of ammonium occurred by means of ion exchange and molecule adsorption with the ≡ Si-OH groups, while phosphate adsorption was based on the calcium phosphate precipitation reaction and formation of inner-sphere complexes with ≡ M-OH groups. The adsorption processes of ammonium and phosphate were well described by the pseudo-second-order kinetic model and the Freundlich isotherm model. Adsorption of phosphate was endothermic, while ammonium adsorption was exothermic. Furthermore, the maximum ammonium and phosphate adsorption capacities of NL was 23.24 mg N g(-1) and 4.01 mg P g(-1) at an initial pH of 9 and 10, respectively. Results demonstrated that nutrient-adsorbed NL used as compound fertilizer or conventional fertilizer superaddition was feasible for its high contents of N and P as well as its environmental friendliness.

  2. 76 FR 47238 - Ammonium Nitrate From Russia

    Science.gov (United States)

    2011-08-04

    ...)). Background The Commission instituted this review on March 1, 2011 (76 FR 11273) and determined on June 6, 2011 that it would conduct an expedited review (76 FR 34749, June 14, 2011). The Commission transmitted... COMMISSION Ammonium Nitrate From Russia Determination On the basis of the record \\1\\ developed in the...

  3. 21 CFR 184.1133 - Ammonium alginate.

    Science.gov (United States)

    2010-04-01

    ...: Category of food Maximum level of use in food (as served) (percent) Functional use Confections, frostings... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium alginate. 184.1133 Section 184.1133 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...

  4. Topaz concentrate desiliconization with ammonium bifluoride

    OpenAIRE

    Andreev, V. A.; Buynovskiy, A. S.; Andreev, Artyom Andreevich; Dyachenko, Alexander Nikolaevich

    2007-01-01

    Fluoridizing agent for the process of topaz concentrate desiliconization has been selected, topaz thermodynamic potentials have been appraised, thermodynamic probabilities of fluorination reaction of topaz concentrate main constituents have been calculated. The results of studying the concentrate desiliconization process with ammonium bifluoride by the methods of thermogravimetry, RFA, microphotography are presented

  5. Detonation characteristics of ammonium nitrate products

    NARCIS (Netherlands)

    Kersten, R.J.A.; Hengel, E.I.V. van den; Steen, A.C. van der

    2006-01-01

    The detonation properties of ammonium nitrate (AN) products depend on many factors and are therefore, despite the large amount of information on this topic, difficult to assess. In order to further improve the understanding of the safety properties of AN, the European Fertilizer Manufacturers Associ

  6. Ammonium ions determination with polypyrrole modified electrode

    Directory of Open Access Journals (Sweden)

    Luiz Henrique Dall´Antonia

    2007-03-01

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

  7. 76 FR 46907 - Ammonium Nitrate Security Program

    Science.gov (United States)

    2011-08-03

    ... comments. SUMMARY: This proposed rule would implement anti-terrorism measures to better secure the homeland... purpose of preventing the use of ammonium nitrate in an act of terrorism. This proposed rule seeks comment... Administration POC Point of Contact QATT Qualified Anti-Terrorism Technology RFA Regulatory Flexibility...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-02-15

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

  9. Thermogravimetric control of intermediate compounds in uranium metallurgy

    International Nuclear Information System (INIS)

    The thermal decomposition of some intermediate compounds in the metallurgy of the uranium as uranium peroxide, ammonium uranate, uranium and ammonium penta-fluoride, uranium tetrafluoride and uranous oxide has been study by means of the Chevenard's thermo balance. Some data on pyrolysis of synthetic mixtures of intermediate compounds which may occasionally appear during the industrial process, are given. Thermogravimetric methods of control are suggested, usable in interesting products in the uranium metallurgy. (Author) 20 refs

  10. Impact of Ammonium on Syntrophic Organohalide-Respiring and Fermenting Microbial Communities.

    Science.gov (United States)

    Delgado, Anca G; Fajardo-Williams, Devyn; Kegerreis, Kylie L; Parameswaran, Prathap; Krajmalnik-Brown, Rosa

    2016-01-01

    Syntrophic interactions between organohalide-respiring and fermentative microorganisms are critical for effective bioremediation of halogenated compounds. This work investigated the effect of ammonium concentration (up to 4 g liter(-1) NH4 (+)-N) on trichloroethene-reducing Dehalococcoides mccartyi and Geobacteraceae in microbial communities fed lactate and methanol. We found that production of ethene by D. mccartyi occurred in mineral medium containing ≤2 g liter(-1) NH4 (+)-N and in landfill leachate. For the partial reduction of trichloroethene (TCE) to cis-dichloroethene (cis-DCE) at ≥1 g liter(-1) NH4 (+)-N, organohalide-respiring dynamics shifted from D. mccartyi and Geobacteraceae to mainly D. mccartyi. An increasing concentration of ammonium was coupled to lower metabolic rates, longer lag times, and lower gene abundances for all microbial processes studied. The methanol fermentation pathway to acetate and H2 was conserved, regardless of the ammonium concentration provided. However, lactate fermentation shifted from propionic to acetogenic at concentrations of ≥2 g liter(-1) NH4 (+)-N. Our study findings strongly support a tolerance of D. mccartyi to high ammonium concentrations, highlighting the feasibility of organohalide respiration in ammonium-contaminated subsurface environments. IMPORTANCE Contamination with ammonium and chlorinated solvents has been reported in numerous subsurface environments, and these chemicals bring significant challenges for in situ bioremediation. Dehalococcoides mccartyi is able to reduce the chlorinated solvent trichloroethene to the nontoxic end product ethene. Fermentative bacteria are of central importance for organohalide respiration and bioremediation to provide D. mccartyi with H2, their electron donor, acetate, their carbon source, and other micronutrients. In this study, we found that high concentrations of ammonium negatively correlated with rates of trichloroethene reductive dehalogenation and

  11. 40 CFR 721.4095 - Quaternary ammonium alkyltherpropyl trialkylamine halides.

    Science.gov (United States)

    2010-07-01

    ... trialkylamine halides. 721.4095 Section 721.4095 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.4095 Quaternary ammonium alkyltherpropyl trialkylamine halides. (a... generically as quaternary ammonium alkyltherpropyl trialkylamine halides (PMNs...

  12. 21 CFR 184.1296 - Ferric ammonium citrate.

    Science.gov (United States)

    2010-04-01

    ... citrate (iron (III) ammonium citrate) is prepared by the reaction of ferric hydroxide with citric acid, followed by treatment with ammonium hydroxide, evaporating, and drying. The resulting product occurs in two forms depending on the stoichiometry of the initial reactants. (1) Ferric ammonium citrate (iron...

  13. 40 CFR 721.10099 - Dialkyl dimethyl ammonium carbonate (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Dialkyl dimethyl ammonium carbonate... Specific Chemical Substances § 721.10099 Dialkyl dimethyl ammonium carbonate (generic). (a) Chemical... as dialkyl dimethyl ammonium carbonate (1:1) (PMN P-03-715) is subject to reporting under...

  14. Anti-herpesviral effects of a novel broad range anti-microbial quaternary ammonium silane, K21.

    Science.gov (United States)

    Gulve, Nitish; Kimmerling, Kirk; Johnston, Allen D; Krueger, Gerhard R; Ablashi, Dharam V; Prusty, Bhupesh K

    2016-07-01

    We have created a novel quaternary ammonium silane, K21 through sol-gel chemistry, using an ethoxylated version of an organosilane quaternary ammonium compound and TetraEthyl Ortho Silicate (TEOS) as precursors. Previous studies using the precursor molecule quaternary ammonium compounds (QACs) and a methacryloxy version of K21, primarily designed for use in dental healthcare, have shown inhibited growth properties against several types of gram-positive and gram-negative bacteria including Escherichia coli, Streptococcus mutans, Actinomyces naeslundii and Candida albicans etc. Here we tested the effect of K21 on HSV-1, HHV-6A and HHV-7 in in vitro cell culture infection models. Our results show growth inhibitory effect of K21 on HSV-1, HHV-6A and HHV-7 infection. PMID:27181377

  15. Oxidation behavior of ammonium in a 3-dimensional biofilm-electrode reactor.

    Science.gov (United States)

    Tang, Jinjing; Guo, Jinsong; Fang, Fang; Chen, Youpeng; Lei, Lijing; Yang, Lin

    2013-12-01

    Excess nitrogenous compounds are detrimental to natural water systems and to human health. To completely realize autohydrogenotrophic nitrogen removal, a novel 3-dimensional biofilm-electrode reactor was designed. Titanium was electroplated with ruthenium and used as the anode. Activated carbon fiber felt was used as the cathode. The reactor was separated into two chambers by a permeable membrane. The cathode chamber was filled with granular graphite and glass beads. The cathode and cathode chamber were inhabited with domesticated biofilm. In the absence of organic substances, a nitrogen removal efficiency of up to 91% was achieved at DO levels of 3.42 +/- 0.37 mg/L when the applied current density was only 0.02 mA/cm2. The oxidation of ammonium in biofilm-electrode reactors was also investigated. It was found that ammonium could be oxidized not only on the anode but also on particle electrodes in the cathode chamber of the biofilm-electrode reactor. Oxidation rates of ammonium and nitrogen removal efficiency were found to be affected by the electric current loading on the biofilm-electrode reactor. The kinetic model of ammonium at different electric currents was analyzed by a first-order reaction kinetics equation. The regression analysis implied that when the current density was less than 0.02 mA/cm2, ammonium removal was positively correlated to the current density. However, when the current density was more than 0.02 mA/cm2, the electric current became a limiting factor for the oxidation rate of ammonium and nitrogen removal efficiency. PMID:24649670

  16. Unique Inner Pore Properties of BK Channels Revealed by Quaternary Ammonium Block

    OpenAIRE

    Li, Weiyan; Aldrich, Richard W.

    2004-01-01

    Potassium channels have a very wide distribution of single-channel conductance, with BK type Ca2+-activated K+ channels having by far the largest. Even though crystallographic views of K+ channel pores have become available, the structural basis underlying BK channels' large conductance has not been completely understood. In this study we use intracellularly applied quaternary ammonium compounds to probe the pore of BK channels. We show that molecules as large as decyltriethylammonium (C10) a...

  17. Impact of Ammonium on Syntrophic Organohalide-Respiring and Fermenting Microbial Communities

    OpenAIRE

    Anca G Delgado; Fajardo-Williams, Devyn; Kegerreis, Kylie L.; Parameswaran, Prathap; Krajmalnik-Brown, Rosa

    2016-01-01

    ABSTRACT Syntrophic interactions between organohalide-respiring and fermentative microorganisms are critical for effective bioremediation of halogenated compounds. This work investigated the effect of ammonium concentration (up to 4 g liter−1 NH4 +-N) on trichloroethene-reducing Dehalococcoides mccartyi and Geobacteraceae in microbial communities fed lactate and methanol. We found that production of ethene by D. mccartyi occurred in mineral medium containing ≤2 g liter−1 NH4 +-N and in landfi...

  18. Oxidation of ferrocene by thiocyanic acid in the presence of ammonium oxalate

    Energy Technology Data Exchange (ETDEWEB)

    Ruslin, Farah bt; Yamin, Bohari M. [School of Chemical Science and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (Malaysia)

    2014-09-03

    A flake-like crystalline salt was obtained from the reaction of ferrocene, oxalic acid and ammonium thiocyanate in ethanol The elemental analysis and spectroscopic data were in agreement with the preliminary X-ray molecular structure. The compound consists of four ferrocenium moieties and a counter anion consisting of two (tetraisothiocyanato)iron(III) linked by an oxalato bridging group in such a way that both iron central atoms adopt octahedral geometries.

  19. Detonation Properties of Ammonium Dinitramide (ADN)

    Science.gov (United States)

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

    1999-06-01

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

  20. Ammonium-acetate is sensed by gustatory and olfactory neurons in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Christian Frøkjaer-Jensen

    Full Text Available BACKGROUND: Caenorhabditis elegans chemosensation has been successfully studied using behavioral assays that treat detection of volatile and water soluble chemicals as separate senses, analogous to smell and taste. However, considerable ambiguity has been associated with the attractive properties of the compound ammonium-acetate (NH(4Ac. NH(4Ac has been used in behavioral assays both as a chemosensory neutral compound and as an attractant. METHODOLOGY/MAIN FINDINGS: Here we show that over a range of concentrations NH(4Ac can be detected both as a water soluble attractant and as an odorant, and that ammonia and acetic acid individually act as olfactory attractants. We use genetic analysis to show that NaCl and NH(4Ac sensation are mediated by separate pathways and that ammonium sensation depends on the cyclic nucleotide gated ion channel TAX-2/TAX-4, but acetate sensation does not. Furthermore we show that sodium-acetate (NaAc and ammonium-chloride (NH(4Cl are not detected as Na(+ and Cl(- specific stimuli, respectively. CONCLUSIONS/SIGNIFICANCE: These findings clarify the behavioral response of C. elegans to NH(4Ac. The results should have an impact on the design and interpretation of chemosensory experiments studying detection and adaptation to soluble compounds in the nematode Caenorhabditis elegans.

  1. Development of technology for ammonium nitrate dissociation process

    International Nuclear Information System (INIS)

    Ammonia and ammonium carbonate are frequently used as reagents in fuel production and processing of liquid radioactive wastes. In particular, liquid radioactive wastes that contain ammonium nitrate are generated during operations of metal precipitation. In closed vessels at elevated temperature, for example in evaporators or deposits in tubing, ammonium nitrate may explode due to generation of gaseous nitrogen oxides [2]. In this connection, steps have to be taken to rule out conditions that result in explosion. To do that, ammonium nitrate should be removed even prior to the initial stage of its formation. This report gives results of development of a method of dissociating ammonium nitrate

  2. Review:Anaerobic ammonium oxidation for treatment of ammonium-rich wastewaters

    Institute of Scientific and Technical Information of China (English)

    Lei ZHANG; Ping ZHENG; Chongojian TANG; Ren-cun JIN

    2008-01-01

    The concept of anaerobic ammonium oxidation (ANAMMOX) is presently of great interest.The functional bacteria belonging to the Planctomycete phylum and their metabolism are investigated by microbiologists.Meanwhile,the ANAMMOX is equally valuable in treatment of ammonium-rich wastewaters.Related processes including partial nitritation-ANAMMOX and completely autotrophic nitrogen removal over nitrite (CANON) have been developed,and lab-scale experiments proved that both processes were quite feasible in engineering with appropriate control.Successful full-scale practice in the Netherlands will ac-celerate application of the process in future.This review introduces the microbiology and more focuses on application of the ANAMMOX process.

  3. Review: Mechanisms of ammonium toxicity and the quest for tolerance.

    Science.gov (United States)

    Esteban, Raquel; Ariz, Idoia; Cruz, Cristina; Moran, Jose Fernando

    2016-07-01

    Ammonium sensitivity of plants is a worldwide problem, constraining crop production. Prolonged application of ammonium as the sole nitrogen source may result in physiological and morphological disorders that lead to decreased plant growth and toxicity. The main causes of ammonium toxicity/tolerance described until now include high ammonium assimilation by plants and/or low sensitivity to external pH acidification. The various ammonium transport-related components, especially the non-electrogenic influx of NH3 (related to the depletion of (15)N) and the electrogenic influx of NH4(+), may contribute to ammonium accumulation, and therefore to NH3 toxicity. However, this accumulation may be influenced by increasing K(+) concentration in the root medium. Recently, new insights have been provided by "omics" studies, leading to a suggested involvement of GDP mannose-pyrophosphorylase in the response pathways of NH4(+) stress. In this review, we highlight the cross-talk signaling between nitrate, auxins and NO, and the importance of the connection of the plants' urea cycle to metabolism of polyamines. Overall, the tolerance and amelioration of ammonium toxicity are outlined to improve the yield of ammonium-grown plants. This review identifies future directions of research, focusing on the putative importance of aquaporins in ammonium influx, and on genes involved in ammonium sensitivity and tolerance. PMID:27181951

  4. The analysis of 15N/14N ratios in natural samples, with emphasis on nitrate and ammonium in precipitation

    International Nuclear Information System (INIS)

    The nitrogen cycle is one of the most important of the earth's elemental cycles. The report describes the procedures used for the analysis of 15N/14N ratios in ammonium and nitrate (and organic nitrogen), and summaries without discussion the data obtained for precipitation (by rain and dust) collected at the Council for Scientific and Industrial Research site. The 15N/14N ratios of nitrogen compounds were determined on N2 gas. This was measured by means of a mass spectrometer. The isotopic analysis of organic nitrogen were conducted in two ways: Kjeldahl digestion to form ammonium, and Dumas combustion directly to N2

  5. Effects of uranium compounds on skin

    International Nuclear Information System (INIS)

    The following uranium compounds were topically applied to the dorsal skin of 35 day-old Wistar rats (60 g, male): uranium dioxide, uranyl nitrate, uranyl acetate, ammonium uranyl tricarbonate and ammonium diuranate. Percutaneous absorption was mediated with the aid of a vehicle and known quantities of various particle-sized batches of uranium compounds were directly implanted in the subcutaneous tissue. Animals were sacrificed 3, 6, 24 and 48 hours after implantation. Subcutaneous tissue and muscle underneath the implantation site were anlaysed by light and electron microscopy. A Cameca 322 X-ray microanalyzer was used to analyze uranium traces in calcified tissue (bones and teeth) and kidneys. A steady loss in body weight was observed in animals given high concentration of uranyl nitrate and ammonium uranyl tricarbonate. All animals died five days after the onset of the experiment due to renal failure. Slightly soluble compounds, ammonium diuranate and uranyl acetate, caused only a slight decrease in body weight. Uranium dioxide, the most insoluble compound used, induced only a transitory slight body weight decrease. Histopathological study revealed damages to the tissues of topicated skin, hair follicles and adnexal glands. High concentration of uranium was indicated in bone, teeth and kidneys by X-ray scanning

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

    Science.gov (United States)

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

    2015-09-01

    The transformation of nitrite-reducing anaerobic ammonium oxidation to sulfate-reducing anaerobic ammonium oxidation in an UASB was performed and the changes in microbial community were studied. The result showed that the sulfate reducing anaerobic ammonium oxidation process was successfully accomplished after 177 days' operation. The removal rate of ammonium nitrogen and sulfate were up to 58. 9% and 15. 7%, the removing load of ammonium nitrogen and sulfate were 74. 3 mg.(L.d)-1 and 77. 5 mg.(L.d)-1 while concentration of ammonium nitrogen and sulfate of influent were 130 mg.(L.d)-1 and 500 mg.(L.d)-1, respectively. The lost nitrogen and sulphur was around 2 in molar ratio. The pH value of the effluent was lower than that of the influent. Instead of Candidatus brocadia in nitrite reducing anaerobic ammonium oxidation granular sludge, Bacillus benzoevorans became the dominant species in sulfate reducing anaerobic ammonium oxidation sludge. The dominant bacterium in the two kinds of anaerobic ammonium oxidation process is different. Our results imply that the two anaerobic ammonium oxidation processes are carried out by different kind of bacterium. PMID:26717697

  7. Quaternary ammonium derivatives as spasmolytics for irritable bowel syndrome.

    Science.gov (United States)

    Evangelista, S

    2004-01-01

    Quaternary ammonium derivatives such as cimetropium, n-butyl scopolammonium, otilonium and pinaverium bromide have been discovered and developed as potent spasmolytics of the gastrointestinal tract. Their pharmacological activity has been proven in both "in vivo" and "in vitro" studies of hypermotility. "In vitro" experiments showed that they possess antimuscarinic activity at nM level but only pinaverium and otilonium are endowed with calcium channel blocker properties. These latter compounds relaxed the gastrointestinal smooth muscle mainly through a specific inhibition of calcium ion influx through L-type voltage operated calcium channels. Molecular pharmacology trials have indicated that pinaverium and otilonium can bind specific subunits of the calcium channel in the external surface of the plasma membrane and in this way they block the machinery of the contraction. Recent evidence showed that otilonium is able to bind tachykinin NK(2) receptors and not only inhibits one of the major contractile agents but can reduce the activation of afferent nerves devoted to the passage of sensory signals from the periphery to the central nervous system. Thanks to their typical physico-chemical characteristics, they are poorly absorbed by the systemic circulation and generally remain in the gastrointestinal tract where they exert the muscle relaxant activity by a local activity. Some differences exists in the absorption among these compounds: both n-butyl scopolammonium and cimetropium are partially taken up in the bloodstream, pinaverium has a low absorption (8-10 %) but is endowed with an excellent hepato-biliary excretion and otilonium, which has the lowest absorption (3 %), is almost totally excreted by faeces. Quaternary ammonium derivatives are widely used for the treatment of irritable bowel syndrome and recent meta-analyses have supported their efficacy in this disease. Due to its therapeutic index, the use of n-butyl scopolammonium is more indicated to treat acute

  8. Ammonium iron(III phosphate(V fluoride, (NH40.5[(NH40.375K0.125]FePO4F, with ammonium partially substituted by potassium

    Directory of Open Access Journals (Sweden)

    Lei Wang

    2009-01-01

    Full Text Available The title compound, ammonium potassium iron(III phosphate fluoride, (NH40.875K0.125FePO4F, is built from zigzag chains ∞1{[FeO4F2]7−}, with Fe3+ in a distorted octahedral coordination, extending along both the [011] and [0overline{1}1] directions. These chains are made up of alternating trans-[FeO4F2] and cis-[FeO4F2] octahedra via shared F-atom corners, and are linked by PO4 tetrahedra, resulting in an open-framework structure with channels along the [010] and [100] directions. There are two crystallographically independent ammonium sites: one in the [010] channels and the other, partially substituted by K+ ions, in the [100] channels. The ammonium in the [010] channels is fixed to the framework via eight hydrogen bonds (six N—H...O and two N—H...F.

  9. Reassimilation of ammonium in Lotus japonicus.

    Science.gov (United States)

    Betti, Marco; García-Calderón, Margarita; Pérez-Delgado, Carmen M; Credali, Alfredo; Pal'ove-Balang, Peter; Estivill, Guillermo; Repčák, Miroslav; Vega, José M; Galván, Francisco; Márquez, Antonio J

    2014-10-01

    This review summarizes the most recent results obtained in the analysis of two important metabolic pathways involved in the release of internal sources of ammonium in the model legume Lotus japonicus: photorespiratory metabolism and asparagine breakdown mediated by aparaginase (NSE). The use of photorespiratory mutants deficient in plastidic glutamine synthetase (GS2) enabled us to investigate the transcriptomics and metabolomic changes associated with photorespiratory ammonium accumulation in this plant. The results obtained indicate the existence of a coordinate regulation of genes involved in photorespiratory metabolism. Other types of evidence illustrate the multiple interconnections existing among the photorespiratory pathway and other processes such as intermediate metabolism, nodule function, and secondary metabolism in this plant, all of which are substantially affected in GS2-deficient mutants because of the impairment of the photorespiratory cycle. Finally, the importance of asparagine metabolism in L. japonicus is highlighted because of the fact that asparagine constitutes the vast majority of the reduced nitrogen translocated between different organs of this plant. The different types of NSE enzymes and genes which are present in L. japonicus are described. There is a particular focus on the most abundant K(+)-dependent LjNSE1 isoform and how TILLING mutants were used to demonstrate by reverse genetics the importance of this particular isoform in plant growth and seed production.

  10. Response of anaerobic ammonium oxidation to inorganic nitrogen fluctuations in temperate estuarine sediments

    Science.gov (United States)

    Teixeira, Catarina; Magalhães, Catarina; Joye, Samantha B.; Bordalo, Adriano A.

    2016-07-01

    The discovery of anaerobic ammonium oxidation (anammox) highlighted the importance of alternative metabolic pathways to inorganic nitrogen removal in natural environments, particularly in those subjected to increased nitrate inputs, such as estuaries. Laboratory enrichment experiments were used to test the effect of increasing loads of nitrate (NO3-), nitrite (NO2-), and ammonium (NH4+) on the anammox process. Three Atlantic temperate estuaries (NW Portugal) were investigated along a salinity gradient, and anammox activity was measured under different NO3-, NO2-, and NH4+ treatments, using the isotope pairing technique. Obtained results showed that NO3- stimulated denitrification but not anammox, whereas NO2- additions had a positive effect on anammox activity, confirming its role as a key environmental control. On the other hand, increasing NH4+ concentrations seemed to inhibit anammox for low salinity sites. Our findings suggested an important role of the natural availability of nitrogen compounds in regulating anammox and the magnitude of anammox versus denitrification in estuarine environments.

  11. Kinetic and Equilibrium Studies of Sorption of Ammonium in the Soil-Water Environment in Agricultural Areas of Central Poland

    Directory of Open Access Journals (Sweden)

    Anna Sieczka

    2016-09-01

    Full Text Available Sorption characteristics of nitrogen compounds is necessary in ascertaining their fate in the soil-water environment. This paper presents a laboratory “batch” experiment for determining the sorption parameters of ammonium in the soil-water environment. Three agricultural soils (silt loam, loam, and sand with different contents of the clay fraction, significantly affecting the range of the adsorption of contaminants on the surface of solid particles, were chosen as research material. Considering the composition of ammonium nitrate (a commonly used fertilizer in Poland, ammonium solutions with a concentration of 0–52 mg NH4+/L were used as markers. Pseudo-first order, pseudo-second order, and intra-particle diffusion kinetic models were used to describe the mechanisms of ammonium adsorption. Experimental data obtained from the equilibrium tests have been analysed using two-parameter (Freundlich, Langmuir, Temkin and three-parameter (Redlich-Peterson, Hill, Sips models. In order to adjust the parameters of the considered isotherms to the experimental data, the method of minimization of the sum of squared errors was used. Additionally, the maximum sorption capacities and reduction ratios of ammonium versus time were assessed. It was observed that the presence of silt loam and loam in the soil profile can increase the possibility of ammonium adsorption up to almost 20%. Taking into consideration the results of the batch tests, it was concluded that ammonium adsorption attains equilibrium within 48 h. Experimental data was best followed by the pseudo-second order equation and the adsorption isotherm conformed to the Redlich-Peterson model for loam and sand.

  12. Relating dynamic conditions to the performance of biological rapid sand filters used to remove ammonium, iron, and manganese from drinking water

    OpenAIRE

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

    2012-01-01

    Biological rapid sand filters are used throughout the world to remove both particulates and dissolved compounds from drinking water and is a proven and effective treatment technique for providing safe and secure drinking water. However, experience has shown that some filters have problems consistently meetingregulatory guidelines for compounds like ammonium and reduced forms of iron and manganese. These compounds can cause biological instability in the distribution system and can lead to many...

  13. Synthesis and characterization of ammonium phosphate fertilizers with boron

    Directory of Open Access Journals (Sweden)

    ANGELA MAGDA

    2010-07-01

    Full Text Available The concentration of boron, an essential micronutrient for plants, presents a narrow range between deficiency and toxicity. In order to provide the boron requirement for plants, and to avoid toxicity problems, boron compounds are mixed with basic fertilizers. Sodium borate pentahydrate was used as a boron source. Ammonium orthophosphates fertilizers with boron were prepared by neutralizing phosphoric acid with ammonia and addition of variable amounts of sodium tetraborate pentahydrate to the reaction mixture at a NH3:H3PO4 molar ratio of 1.5. The fertilizers obtained with boron contents ranging from 0.05 to 1 % (w/w were fully characterized by chemical analysis, thermal analysis, X-ray diffraction and infrared spectrophotometry. The studies showed that up to 500 °C, regardless of the boron content, no significant changes concerning thermal stability and nutritional properties occurred. Above 500 °C, an increase of thermal stability with an increase of the boron content was observed. X-Ray diffraction of a heat-treated sample containing 5 % (w/w boron indicated the appearance of boron orthophosphate, BPO4, as a new crystalline phase, and the disappearance of the previous structures above 500 °C, which explains the increase in thermal stability.

  14. The Structure of Ammonium D,L-Tartrate

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The single crystals of the title compound NH4+C4H5O6- (C4H9NO6, Mr = 167.1) were obtained from a hot aqueous solution containing L-glutamine and D,L-tartaric acid in mole ratio1:1.5. The crystal belongs to monoclinic space group P21/c with a = 7.646(2), b = 7.804(2), c = 11.502(3)?, β = 102.26(2)o, V = 670.7(3)?3, Z = 4, F(000) = 352, Dc = 1.655 g.cm-3, ((MoK() = 0.16 mm-1, R = 0.035, wR = 0.094 for 1028 observed reflections (I>2((I)). The enatiomeric anions of the tartrate with both (2S,3S)- and (2R,3R)-configuration co-exist in the unit cell. The carbon skeleton assumes a coplanar arrangement with a torsion angle of 181.5o. The three- dimensional H-bonding network exists in the crystal. While tartrate groups link each other by H-bonds between carboxyl and hydroxyl groups, the ammonium cations insert between the tartrate groups to form a sandwich-like crystal structure.

  15. Hydration Structure of the Quaternary Ammonium Cations

    KAUST Repository

    Babiaczyk, Wojtek Iwo

    2010-11-25

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

  16. Racer (Ammonium Nonanoate) weed control evaluation for onions

    Science.gov (United States)

    Racer has been labeled as a herbicide for food use and is currently under consideration as an organic herbicide for organically grown food crops. The main component (40%) of Racer is ammonium nonanoate (ammonium pelargonate), which occurs in nature and primarily formed from biodegradation of higher...

  17. Ammonium and hydroxylamine uptake and accumulation in Nitrosomonas

    NARCIS (Netherlands)

    Schmidt, I.; Look, C.; Bock, E.; Jetten, M.S.M.

    2004-01-01

    Starved cells of Nitrosomonas europaea and further ammonia oxidizers were able to rapidly accumulate ammonium and hydroxylamine to an internal concentration of about 1 and 0.8 M, respectively. In kinetic studies, the uptake/accumulation rates for ammonium [3.1 mmol (g protein)(-1) min(-1)] and hydro

  18. How to make a living from anaerobic ammonium oxidation

    NARCIS (Netherlands)

    Kartal, B.; De Almeida, N.M.; Maalcke, W.J.; Op den Camp, H.J.M.; Jetten, M.S.M.; Keltjens, J.T.

    2013-01-01

    Anaerobic ammonium-oxidizing (anammox) bacteria primarily grow by the oxidation of ammonium coupled to nitrite reduction, using CO2 as the sole carbon source. Although they were neglected for a long time, anammox bacteria are encountered in an enormous species (micro)diversity in virtually any anoxi

  19. Hydrothermal oxidation of organic wastes using reclaimed ammonium nitrate

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-04-01

    Ammonium nitrate is being studied as an alternative for ammonium perchlorate as an oxidizing agent in Department of Defense 1.1 and 1.3 rocket propellants. Use of ammonium nitrate would eliminate the HCl produced by ammonium perchlorate upon thermal decomposition. To stabilize the ammonium nitrate, which suffers from phase instability, potassium dinitramide (KDN) is added. This increased use of ammonium nitrate will ultimately create a need for environmentally responsible processes to reuse ammonium nitrate extracted from demilitarized rocket motors. Ammonium Nitrate was investigated as an oxidizing agent for methanol, acetic acid and phenol. High removal of organic, ammonia and nitrate was achieved at stoichiometric concentrations. The oxidation of ammonia by nitrate was much faster than the oxidation of either methanol or acetic acid. Phenol, however, was in strong competition with ammonia for the oxidizer (nitrate). Nitrogen products included N{sub 2}, N{sub 2}O, NO{sub 2{sup {minus}}} as well as toxic NO and trace amounts of NO{sub 2}. Carbon products were CO{sub 2}, HCO{sub 3{sup {minus}}}, CO{sub 3}{sup 2{minus}}, and CO.

  20. 21 CFR 172.165 - Quaternary ammonium chloride combination.

    Science.gov (United States)

    2010-04-01

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

  1. Density functional theory calculations of the molecular structure and the vibrational spectra of bis-tetrapropyl-ammonium hexachloro-dizincate

    Science.gov (United States)

    Ben Gzaiel, M.; Oueslati, A.; Chaabane, I.; Gargouri, M.

    2016-10-01

    The molecular structure and vibrational spectra of bis-tetrapropyl-ammonium hexachloro-dizincate in the ground state have been investigated by density functional method (DFT) using the B3LYP method with the LanL2DZ and LanL2MB basis set. Infrared and Raman spectroscopes of the [N(C3H7)4]2Zn2Cl6 compound have been measured at room temperature in the frequencies range (3500-400 cm-1) and (3500-100 cm-1), respectively. The optimized geometric shows that the calculated values obtained by B3LYP/LanL2DZ basis are in much better agreement with the experimental data than those obtained by B3LYP/LanL2MB. Actually the theoretical vibrational spectra (B3LYP/LanL2DZ) of the title compound have been interpreted by means of potential energy distribution (PED) which is in good agreement with the experimental data. The comparison of the infrared spectrum of the tetrapropyl-ammonium chloride ligand with those of the bis-tetrapropyl-ammonium hexachloro-dizincate compound confirms an increase of the wavenumber in the [N(C3H7)4]2Zn2Cl6 compound. This can be explained by an increase of the electrostatic interactions of the [N(C3H7)4]Cl ligand.

  2. Glyoxal uptake on ammonium sulphate seed aerosol: reaction products and reversibility of uptake under dark and irradiated conditions

    Directory of Open Access Journals (Sweden)

    M. M. Galloway

    2008-12-01

    Full Text Available Chamber studies of glyoxal uptake onto neutral ammonium sulphate aerosol were performed under dark and irradiated conditions to gain further insight into processes controlling glyoxal uptake onto ambient aerosol. Organic fragments from glyoxal dimers and trimers were observed within the aerosol under dark and irradiated conditions; glyoxal oligomer formation and overall organic growth were found to be reversible under dark conditions. Analysis of high-resolution time-of-flight aerosol mass spectra provides evidence for irreversible formation of carbon-nitrogen (C-N compounds in the aerosol. These compounds are likely to be imidazoles formed by reaction of glyoxal with the ammonium sulphate seed. To the authors' knowledge, this is the first time C-N compounds resulting from condensed phase reactions with ammonium sulphate seed have been detected in aerosol. Organosulphates were not detected under dark conditions. However, active oxidative photochemistry, similar to that found in cloud processing, was found to occur within aerosol during irradiated experiments. Organosulphates, carboxylic acids, and organic esters were identified within the aerosol. Our study suggests that both C-N compound formation and photochemical processes should be considered in models of secondary organic aerosol formation via glyoxal.

  3. Seasonal patterns of ammonium regeneration from size-fractionated microheterotrophs

    Science.gov (United States)

    Maguer, Jean-François; L'Helguen, Stéphane; Madec, Christian; Le Corre, Pierre

    1999-11-01

    Ammonium regeneration by size-fractionated plankton was measured for 1 year at a coastal station in the shallow well-mixed waters of the western English Channel. Rates of ammonium regeneration in the Journal of Plankton Research, 18, 355-370). Total ammonium regenerated in a year by the microheterotrophs was 15 g N m -2, equivalent to about 60% of the total nitrogen uptake. Microplankton (200-15 μm) accounted for about 50% of the regeneration measured between early spring and late summer. Percent contribution of nanoplankton to total ammonium regeneration varied considerably between the seasons, from very high (83-88%) levels in winter to very low (2-13%) levels in summer. Contribution by picoplankton (nano- and picoplankton fractions, appears to be different from that in deep well-mixed waters. Here, the relative contribution of ciliates and bacteria to ammonium regeneration shows little variation with an increase in macrozooplankton biomass.

  4. In Vitro Activity of Quaternary Ammonium Surfactants against Streptococcal, Chlamydial, and Gonococcal Infective Agents.

    Science.gov (United States)

    Inácio, Ângela S; Nunes, Alexandra; Milho, Catarina; Mota, Luís Jaime; Borrego, Maria J; Gomes, João P; Vaz, Winchil L C; Vieira, Otília V

    2016-06-01

    Quaternary ammonium compounds (QAC) are widely used, cheap, and chemically stable disinfectants and topical antiseptics with wide-spectrum antimicrobial activities. Within this group of compounds, we recently showed that there are significant differences between the pharmacodynamics of n-alkyl quaternary ammonium surfactants (QAS) with a short (C12) alkyl chain when in vitro toxicities toward bacterial and mammalian epithelial cells are compared. These differences result in an attractive therapeutic window that justifies studying short-chain QAS as prophylactics for sexually transmitted infections (STI) and perinatal vertically transmitted urogenital infections (UGI). We have evaluated the antimicrobial activities of short-chain (C12) n-alkyl QAS against several STI and UGI pathogens as well as against commensal Lactobacillus species. Inhibition of infection of HeLa cells by Neisseria gonorrhoeae and Chlamydia trachomatis was studied at concentrations that were not toxic to the HeLa cells. We show that the pathogenic bacteria are much more susceptible to QAS toxic effects than the commensal vaginal flora and that QAS significantly attenuate the infectivity of N. gonorrhoeae and C. trachomatis without affecting the viability of epithelial cells of the vaginal mucosa. N-Dodecylpyridinium bromide (C12PB) was found to be the most effective QAS. Our results strongly suggest that short-chain (C12) n-alkyl pyridinium bromides and structurally similar compounds are promising microbicide candidates for topical application in the prophylaxis of STI and perinatal vertical transmission of UGI. PMID:26976875

  5. Adsorption of gaseous formaldehyde and carboxylic acids by ammonium-ion-exchanged alpha-zirconium phosphate.

    Science.gov (United States)

    Hayashi, A; Fujimoto, Y; Ogawa, Y; Nakayama, H; Tsuhako, M

    2005-03-01

    Ammonium-ion-exchanged alpha-Zr(HPO(4))(2)H(2)O (alpha-ZrP) was obtained as a single phase with the interlayer distance of 9.4 A by the ion-exchange of proton with ammonium ion. The ammonium ion-exchanged alpha-ZrP could adsorb ill-smelling gases, such as formaldehyde and carboxylic acids (formic acid, acetic acid, propionic acid, and butyric acid). The adsorption amounts of carboxylic acids increased in the order, butyric acidadsorption amount of formaldehyde was the same as that of butyric acid. It was cleared that the adsorbed formaldehyde was partially decomposed to formic acid and methanol by self oxidation-reduction reaction in the interlayer region as evidenced by solid-state NMR. Thereby the interlayer distance after the adsorption of formaldehyde expanded to 14.4 A. In the case of formic acid, it was cointercalated into the interlayer region, and the interlayer distance expanded to 11.1 A. On the other hand, the interlayer distance of the other carboxylic acid-adsorbed compounds decreased to 7.6 A due to release by the evacuation.

  6. Effect of zinc borate on the thermal degradation of ammonium polyphosphate

    International Nuclear Information System (INIS)

    The thermal behaviour of a mixture containing an ammonium polyphosphate based compound (AP760) and zinc borate (ZB) is investigated. After an investigation of the degradation of the pure components, the interactions between them are examined by thermogravimetry. Then, X-ray diffraction (XRD) and 11B and 31P solid-state nuclear magnetic resonance (NMR) measurements have been carried out on residues of mixtures of AP760 and FBZB heat treated at different characteristic temperatures. It reveals the nature of the interactions taking place between the two components. It is demonstrated that reactions lead to the formation of zinc phosphate and of borophosphates. Mechanisms of thermal degradation are proposed

  7. Synthesis, characterization and thermal properties of new aromatic quaternary ammonium bromides: precursors for ionic liquids and complexation studies

    Science.gov (United States)

    Busi, Sara; Lahtinen, Manu; Ropponen, Jarmo; Valkonen, Jussi; Rissanen, Kari

    2004-10-01

    Series of new aromatic R2R‧2N+Br- (R=benzyl, 4-methylbenzyl, 2-phenylethyl, 3-phenylpropyl; R‧=ethyl, methyl, isopropyl) or RR‧2NH+Br--type (R=benzyl, R‧=isopropyl) quaternary ammonium bromides were prepared by using novel synthetic route in which a formamide (N,N-diethylformamide, N,N-dimethylformamide, N,N-diisopropylformamide) is treated with aralkyl halide in presence of a weak base. The compounds were characterized by 1H-NMR and 13C-NMR spectroscopy and mass spectrometry. Structures of the crystalline compounds were determined by X-ray single crystal diffraction, and in addition the powder diffraction method was used to study the structural similarities between the single crystal and microcrystalline bulk material. Three of the compounds crystallized in monoclinic, two in orthorhombic and one in triclinic crystal system, showing ion pairs, which are interconnected by weak hydrogen bonds and weak π - π interactions between the phenyl rings. Three of the compounds appeared as viscous oil or waxes. Finally, TG/DTA and DSC methods were used to analyze thermal properties of the prepared compounds. The lowest melting points were obtained for diethyldi-(2-phenylethyl)ammonium bromide (122.2 °C) and for diethyldi-(3-phenylpropyl)-ammonium bromide (109.1 °C). In general, decomposition of the compounds started at 170-190 °C without identifiable cleavages, thus liquid ranges of 30-70 °C were observed for some of the compounds.

  8. Population of Nitrifying Bacteria and Nitrification in Ammonium Saturated Clinoptilolite

    Science.gov (United States)

    McGilloway, R. L.; Weaver, R. W.; Ming, Douglas W.; Gruener, J.

    1999-01-01

    As humans begin to spend longer periods of time in space, plants will be incorporated into life support systems. Ammonium saturated clinoptilolite is one plant growth substrate but a balance between ammonium and nitrate is needed. A laboratory study was conducted to determine effects of nitrifying bacteria on ammonium concentrations and kinetics of nitrification. Columns containing clinoptilolite substrate amended with nitrifying bacteria obtained from soil enrichment were analyzed weekly for a 90 day period. The enrichment culture initially contained 1 x 10(exp 5) ammonium oxidizing bacteria and 1 x 10(exp 2) nitrite oxidizing bacteria per gram of substrate. Populations of ammonium oxidizing bacteria increased to 1 x 10(exp 6) and nitrite oxidizing bacteria increased to 1 x 10(exp 3) per gram of substrate. The nitrification rate was approximately 0.25mg NO3(-)-N/kg.hr. Experiments were also conducted to enumerate nitrifying bacteria in a clinoptilolite substrate used to grow wheat (Triticum aestivum L.). Seventy days following the initial inoculation with an unknown number of commercial nitrifying bacteria, 1 x 10(exp 5) ammonium oxidizing bacteria per gram of substrate were present. The number of nitrite oxidizing bacteria was between 1 x 10(exp 3) to 10(exp 4) per gram of substrate as measured by the most probable number method. Nitrification rates were approximately 0.20mg NO3(-)-N/kg.hr. Clinoptilolite readily exchanged sufficient concentrations of ammonium to support nitrifying bacteria and they survived well in this medium.

  9. Modelling an Ammonium Transporter with SCLS

    Directory of Open Access Journals (Sweden)

    Angelo Troina

    2009-10-01

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

  10. New quaternary ammonium salts based decontaminants

    Directory of Open Access Journals (Sweden)

    Diana M. Popescu

    2014-06-01

    Full Text Available Decontamination after terrorist attacks or industrial accidents with biological and/or chemical agents („bio-chem“ must be fast and efficient, in order to reduce the number of victims and to eliminate the consequent damages. The decontamination of living biological agents (bacteria, viruses or nonliving ones (toxins, regulators and toxic chemicals could be accomplished by reactions of hydrolysis in various experimental conditions, in particular in alkaline medium, reactions with amines or ammonia, alcohols, phenols etc. and by their transformation into less toxic degradation products. “Bio-chem” intentional or unintentional contamination is a real risk, towards which an effective management must be available to prevent and control it. Decontamination is an essential measure to protect the personnel and the environment. Synthesis and testing of new „bio-chem“ decontaminants, based on quaternary ammonium salts, complete the arsenal of protection against chemical and biological agents. The most effective selected substances could be produced and used for decontamination in accordance with legal procedures

  11. Correlation of anaerobic ammonium oxidation and denitrification

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The feasibility of the nitrous organic wastewater treated was studied in seven anaerobic sequencing batch reactors(ASBRs)(0 #-6 #) which had been run under stable anaerobic ammonium oxidation (Anammox). By means of monitoring and data analysis of COD, NH4+-N, NO2--N, NO3--N and pH, and of microbial test, the results revealed that the optimal Anammox performance was achieved from 2# reactor in which COD/NH4+-N was 1.65, Anammox bacteria and denitrification bacteria could coexist, and Anammox reaction and denitrification reaction could occur simultaneously in the reactors. The ratio of NH4+-N consumed: NO2--N consumed: NO3--N produced was 1:1.38:0.19 in 0# reactor which was not added glucose in the wastewater. When different ratio of COD and NH4+-N was fed for the reactors, the ratio of NO2--N consumed: NH4+-N consumed was in the range of 1.51-2.29 and the ratio of NO3-N produced: NH4+-N consumed in the range of 0-0.05.

  12. Influence of the Different Level Ammonium on NRA and GSA in Sugar Beet(Vulgaris L.)

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Ammonium nitrogen inhibited NR activity in sugar beet,NR activity was lower in endogenous substrate after ammonium nitrogen was used,and the correlation between NR activity and ammonium nitrogen levels was negative.But NR activity raised with the ammonium nitrogen levels raising in exogenous.Ammonium nitrogen prompted GS activity:the correlation between GS activity and ammonium nitrogen was positive,GS activity raised with ammonium nitrogen levels raising,GS activity of roots and leaves had same change trend in sugar beet in the whole growth duration after ammonium nitrogen was used,but GS activity in roots was higher than that in leaves.

  13. Effect of Ammonium Nitrate on Nanoparticle Size Reduction

    Directory of Open Access Journals (Sweden)

    Kalyana C. Pingali

    2008-01-01

    Full Text Available Ammonium nitrate was added to the spraying solution as a foaming agent to reduce the particle size of nanoparticles synthesized in the spray-pyrolysis process. Ammonium nitrate was effective in breaking the aerosol droplet size and generating nanoparticles that were of approximately one order-of-magnitude (from 200 to 20 nm smaller diameter than those created in the absence of ammonium nitrate in the feed solution. This technique makes it possible to control the particle diameter of metallic nanoparticles below 20 nm.

  14. Ammonium salts of carbamodithioic acid as potent vaginal trichomonacides and fungicides.

    Science.gov (United States)

    Kushwaha, Bhavana; Mandalapu, Dhanaraju; Bala, Veenu; Kumar, Lokesh; Pandey, Aastha; Pandey, Deepti; Yadav, Santosh Kumar; Singh, Pratiksha; Shukla, P K; Maikhuri, Jagdamba P; Sankhwar, Satya N; Sharma, Vishnu L; Gupta, Gopal

    2016-01-01

    Chemical attenuation of the reactive oxygen species (ROS)-sensitive anaerobes Trichomonas vaginalis, which is the most prevalent non-viral sexually transmitted infection, and two often coexisting vaginal infections, namely Candida albicans and Staphylococcus aureus, which are opportunistic reproductive tract infections, was attempted with novel ammonium salts of carbamodithioic acid through inhibition of free thiols. In vitro and in vivo efficacies of the designed compounds were evaluated as topical vaginal microbicides. Five compounds showed exceptional activity against drug-resistant and -susceptible strains with negligible toxicity to host (HeLa) cells in vitro in comparison with the standard vaginal microbicide nonoxynol-9 (N-9), without disturbing the normal vaginal flora (i.e. Lactobacillus). The compounds significantly inhibited the cytopathic effects of Trichomonas on HeLa cells in vitro with efficacies comparable with metronidazole (MTZ); however, their efficacy to rescue host cells from co-infection (protozoal and fungal) was greater than that of MTZ. The compounds inhibited β-haemolysis of red blood cells caused by Trichomonas and were found to be active in vivo in the mouse subcutaneous abscess assay. Some compounds rapidly immobilized human sperm. A mechanism involving inhibition of free thiols and consequently the cysteine proteases of T. vaginalis by the new compounds has been proposed. Thus, a unique scaffold of antimicrobial agents has been discovered that warrants further investigation for development as contraceptive vaginal microbicides. PMID:26706422

  15. The adsorption of alkyl-dimethyl-benzyl-ammonium chloride onto cotton nonwoven hydroentangled substrates at the solid-liquid interface is minimized by additive chemistries

    Science.gov (United States)

    Quaternary ammonium compounds, commonly referred to as quats, are cationic surfactants widely used as the active biocide ingredient for disposable disinfecting wipes. The cationic nature of quats results in a strong ionic interaction and adsorption onto wipes materials that have an anionic surface ...

  16. {sup 14}N NQR and relaxation in ammonium nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Stephenson, David, E-mail: david.stephenson@sta.uwi.edu [University of the West Indies, Chemistry Department (Trinidad and Tobago)

    2015-04-15

    The complete {sup 14}N nuclear quadrupole resonance (NQR) spectrum of ammonium nitrate is presented recorded using two double resonance techniques – double contact cross relaxation and zero field NQR. The spectra gave the quadrupole coupling constant (Qcc) and asymmetry parameter (η) values for the nitro of 611 kHz, 0.229 and that for the ammonium nitrogen of 242 kHz, 0.835. The three relaxation transition probabilities have been determined for both the nitro and ammonium nitrogen atoms. The bi-exponential relaxation times (T {sub 1}) were measured at 295 K. The values for nitro are 16.9 s and 10.5 s and that of the ammonium are 23.0 s and 16.4 s.

  17. Ammonium removal by modified zeolite from municipal wastewater

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ya-ping; GAO Ting-yao; JIANG Shang-ying; CAO Da-wen

    2004-01-01

    Ammonium removal by modified zeolite, H-form and Na-form zeolite, were examined by batch-type methods. The adsorption of ammonium on modified zeolite was exothermic process. The saturation adsorption capacity of ammonium on H-form and Na-form zeolite were 21.23 and 41.15 mg/g, respectively. After ten times adsorption- desorption-readsorption cycles the standard deviations of H-form and Na-form zeolite were 6.34% and 6.59%. The zeolite adsorption process has proved cost effective and practical in reducing ammonium by H-form and Na-form zeolite in municipal wastewater from concentration 27.68 mg/L to 2.80 mg/L and 5.91 mg/L.

  18. Fixed Ammonium Content and Maximum Capacity of Ammonium Fixation in Major Types of Tillage Soils in Hunan Province, China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yang-zhu; HUANG Shun-hong; WAN Da-juan; HUANG Yun-xiang; ZHOU Wei-jun; ZOU Ying-bin

    2007-01-01

    In order to understand the status of fixed ammonium, fixed ammonium content, maximum capacity of ammonium fixation, and their influencing factors in major types of tillage soils of Hunan Province, China, were studied with sampling on fields, and laboratory incubation and determination. The main results are summarized as follows: (1) Content of fixed ammonium in the tested soils varies greatly with soil use pattern and the nature of parent material. For the paddy soils, it ranges from 135.4 ± 57.4 to 412.8±32.4 mg kg-1, with 304.7±96.7 mg kg-1 in average; while it ranges from 59.4 to 435.7 mg kg-1, with 230.1 ± 89.2 mg kg1 in average for the upland soils. The soils developed from limnic material and slate had higher fixed ammonium content than the soils developed from granite. The percentage of fixed ammonium to total N in the upland soils is always higher than that in the paddy soils. It ranges from 6.1 ± 3.6% to 16.6 ±4.6%, with 14.0% ± 5.1% in average for the paddy soils and it amounted to 5.8 ±2.0% to 40.1 ± 17.8%, with 23.5 ± 14.2% in average for upland soils. (2) The maximum capacity of ammonium fixation has the same trend with the fixed ammonium content in the tested soils. For all the tested soils, the percentage of recently fixed ammonium to maximum capacity of ammonium fixation is always bellow 20% and it may be due to the fact that the soils have high fertility and high saturation of ammonium-fixing site. (3) The clay content and clay composition in the tested soils are the two important factors influe ncing their fixed ammonium content and maximum capacity of ammonium fixation. The results showed that hydrous mica is the main 2:1 type clay mineral in <0.02 mm clay of the paddy soils, and its content in 0.02-0.002 mm clay is much higher than that in < 0.002 mm clay of the soils. The statistical analysis showed that both the fixed ammonium content and the maximum capacity of ammonium fixation of the paddy soils were positively correlated with

  19. BER OPTIC SENSOR MODIFIED BY GRAFTING OF THE MOLECULARLY IMPRINTED POLYMER FOR THE DETECTION OF AMMONIUM IN AQUEOUS MEDIA

    Directory of Open Access Journals (Sweden)

    N. Lopes,

    2015-07-01

    response to ammonium in the aqueous solutions was obtained using the following experimental conditions: methacrylic acid – 2.1 mmolL-1, ethylene glycol dimethacylate – 7.7 mmolL-1 and NH4Cl – 0.3 mmolL-1 and polymerization time equal to15 minutes. Practical Relevance. Results obtained in this work are applicable in the ecological monitoring of ammonium in the surface waters, in particular, as a part of remote in situ sensing systems. Furthermore, developed optimized method of the grafting of molecularly imprinted polymer on the surface of the polymeric optical fiber is usable for the development of fiber optic sensors for detection of other compounds.

  20. Removal of ammonium from municipal landfill leachate using natural zeolites.

    Science.gov (United States)

    Ye, Zhihong; Wang, Jiawen; Sun, Lingyu; Zhang, Daobin; Zhang, Hui

    2015-01-01

    Ammonium ion-exchange performance of the natural zeolite was investigated in both batch and column studies. The effects of zeolite dosage, contact time, stirring speed and pH on ammonium removal were investigated in batch experiments. The result showed that ammonium removal efficiency increased with an increase in zeolite dosage from 25 to 150 g/L, and an increase in stirring speed from 200 to 250 r/min. But further increase in zeolite dosage and stirring speed would result in an unpronounced increase of ammonium removal. The optimal pH for the removal of ammonium was found as 7.1. In the column studies, the effect of flow rate was investigated, and the total ammonium removal percentage during 180 min operation time decreased with the flow rate though the ion-exchange capacity varied to a very small extent with the flow rate ranging from 4 to 9 mL/min. The spent zeolite was regenerated by sodium chloride solution and the ammonia removal capacity of zeolite changed little or even increased after three regeneration cycles. PMID:26510611

  1. Bioaccumulation and tissue distribution of a quaternary ammonium surfactant in three aquatic species

    Energy Technology Data Exchange (ETDEWEB)

    Knezovich, J.P.; Lawton, M.P.; Inouye, L.S.

    1989-01-01

    Quaternary ammonium compounds (QACs) are commonly used as surfactants in drilling muds and fabric softeners and as biocides in antiseptics and disinfectants. QACs and cationic polyelectrolytes elicit acute toxic effects in aquatic organisms by disrupting the structure and function of gill tissues, which may result in the suffocation of the organism. Little information is available, however, on the relative availability and distribution of QACs in the tissues of aquatic organisms. Information of this nature is required to understand the potential consequences of releases of sublethal concentrations of QACs into the aquatic environment. In this study, hexadecylpyridinium bromide (HPB; CAS 140-72-7) was selected as a compound for initial study because it belongs to a chemical class (alkylpyridinium QACs) that includes the most toxic and environmentally persistent QACs. Clams, minnows, and tadpoles were chosen as test organisms to define the relative availability of HPB to organisms that occupy distinctly different ecological niches.

  2. New synthetic method and properties of ammonium dinitramide; Ammonium dinitramide no shingoseiho to sono butsuri kagakuteki tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Hatano, H.; Onda, T.; Shiino, K. [Hosoya Kako Co. Ltd., Tokyo (Japan). Technology and Development Center; Miyazaki, S.; Matsuura, S. [Nissan Motor Co. Ltd., Saitama (Japan). Research and Development center

    1996-08-31

    Though, ammonium nitrate (AN) has been thought as solid propellant oxidizer, at present, ammonium perchlorate (AP) is mainly used because of the existence of crystal transition point, the improvement of propellant performance on AN and so forth. Ammonium dinitramide (ADN) can be used as an excellent oxidizer for high performance solid propellants, because it has much available oxygen. Furthermore, this propellant is smokeless, since ADN has no halogen resulting in generation of smoke on burning. ADN can be obtained by a new synthetic method which uses urea as starting substance and acquires nitrourea as intermediate product. According to this method, the yield is about 15% based on the amount of nitrourea. The hygroscopicity of this ADN is slightly higher than that of ammonium nitrate. Therefore, it is recommended to handle this substance at 50% of relative humidity or below. 13 refs., 7 figs., 4 tabs.

  3. Methods to Stabilize and Destabilize Ammonium Borohydride

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Thomas K.; Karkamkar, Abhijeet J.; Bowden, Mark E.; Besenbacher, Fleming; Jensen, Torben R.; Autrey, Thomas

    2013-01-21

    Ammonium borohydride, NH4BH4, has a high hydrogen content of ρm = 24.5 wt% H2 and releases 18 wt% H2 below T = 160 °C. However, the half-life of bulk NH4BH4 at ambient temperatures, ~6 h, is insufficient for practical applications. The decomposition of NH4BH4 (ABH2) was studied at variable hydrogen and argon back pressures to investigate possible pressure mediated stabilization effects. The hydrogen release rate from solid ABH2 at ambient temperatures is reduced by ~16 % upon increasing the hydrogen back pressure from 5 to 54 bar. Similar results were obtained using argon pressure and the observed stabilization may be explained by a positive volume of activation in the transition state leading to hydrogen release. Nanoconfinement in mesoporous silica, MCM-41, was investigated as alternative means to stabilize NH4BH4. However, other factors appear to significantly destabilize NH4BH4 and it rapidly decomposes at ambient temperatures into [(NH3)2BH2][BH4] (DADB) in accordance with the bulk reaction scheme. The hydrogen desorption kinetics from nanoconfined [(NH3)2BH2][BH4] is moderately enhanced as evidenced by a reduction in the DSC decomposition peak temperature of ΔT = -13 °C as compared to the bulk material. Finally, we note a surprising result, storage of DADB at temperature < -30 °C transformed, reversibly, the [(NH3)2BH2][BH4] into a new low temperature polymorph as revealed by both XRD and solid state MAS 11B MAS NMR. TA & AK are thankful for support from the US Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. A portion of the research was performed using EMSL, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is operated by Battelle.

  4. 76 FR 49449 - Continuation of Antidumping Duty Order on Solid Fertilizer Grade Ammonium Nitrate From the...

    Science.gov (United States)

    2011-08-10

    ... International Trade Administration Continuation of Antidumping Duty Order on Solid Fertilizer Grade Ammonium... duty investigation on solid fertilizer grade ammonium nitrate (``ammonium nitrate'') from the Russian... Initiation of Five-Year (``Sunset'') Review, 76 FR 11202 (March 1, 2011) and Ammonium Nitrate from...

  5. Effects of Temperature and Drying and Wetting Alternation on Ammonium Fixation in Manured Loessial Soil

    Institute of Scientific and Technical Information of China (English)

    FANXIAOLIN; LILING; 等

    1996-01-01

    Effects of temperature and drying and wetting alternation (DWA) on ammonium fixation in manured loessial soil were studied by means of Batch Equilibrium with varying concentration solutions of ammonium chloride.ammonium fixation time,and soil clay contents.The purpose of the research was to find out the pattern of ammonium fixation affected by the varying factors.The results showed a remarkable variation in ammonium fixation.Fixed ammonium increased with temperature and treatments of DWA.The ammonium fixation in manured loessial soil was characterized by the effect of temperature and DWA.

  6. Quaternary ammonium salt derivatives of allylphenols with peripheral analgesic effect

    Directory of Open Access Journals (Sweden)

    A. B de Oliveira

    1991-01-01

    Full Text Available Ammonium salt derivatives of natural allylphenols were synthesized with the purpose of obtaining potential peripheral analgesics. These drugs, by virtue of their physicochemical properties, would not be able to cross the blood brain barrier. Their inability to enter into the central nervous system (CNS should prevent several adverse effects observed with classical opiate analgesics (Ferreira et al., 1984. Eugenol (1 O-methyleugenol (5 and safrole (9 were submitted to nitration, reduction and permethylation, leading to the ammonium salts 4, 8 and 12. Another strategy applied to eugenol (1, consisting in its conversion to a glycidic ether (13, opening the epoxide ring with secondary amines and methylation, led to the ammonium salts 16 and 17. All these ammonium salts showed significant peripheral analgesic action, in modified version of the Randall-Sellito test (Ferreira et al. 1978, at non-lethal doses. The ammonium salt 8 showed an activity comparable to that of methylnalorphinium, the prototype of an ideal peripheral analgesic (Ferreira et al., 1984.

  7. Difficultly Extractable Fixed Ammonium in Some Soils of China

    Institute of Scientific and Technical Information of China (English)

    CHENBIYUN; CHENGLILI; 等

    1999-01-01

    Ninety-three soil samples and 19 sedimentary rock samples collected from 21 provinces of China were analyzed for their contents of fixed ammonium and total N by Kjeldahl-HF method.Results showed that amount of difficultly extractable fixed ammonium(the fixed ammonium that is not determinable by Kjeldahl procedures commonly used for soils) in soils ranged from 0 to 202 mg kg-1,It was generally more than 50 mg kg-1 in soils in Changji and Turpan districts,Xinjiang,accounting for 3.2%-36.8% with an average of 13.9% of the total N.For some Orthents derived from purple shale and purple sandstone in Sichuan and Hunan provinces and Chao soils derived from secondary loess in Henan Province and Ningxia Autonomous Region it was generally around 30 mg kg-1,accounting for 4%-7% of the total soil N,and for most of the rest of soils studied,with the exception of some subsoils,no or trace difficultly extractable fixed ammonium could be detected.It was sugested that the difficultly extractable fixed ammonium was originated from parent rock,and for slightly weathered soils derived from parent materials rich in this form of N the Kjeldahl method might give underestimation of total soil N.

  8. Photosynthesis mediated decrease in cadmium translocation protect shoot growth of Oryza sativa seedlings up on ammonium phosphate-sulfur fertilization.

    Science.gov (United States)

    Sebastian, Abin; Prasad, M N V

    2014-01-01

    Cadmium (Cd) stress responses in seedlings of two Indian rice cultivars, MTU 7029 and MO 16 were investigated under ammonium-based fertilizer amendment. Cd translocation was reduced by fertilizer treatment. An increase in the production of organic acids as well as nitrogenous compounds and maintenance of nutrient status were implicated for decrease in Cd translocation which in turn promoted shoot growth. Fertilizer treatment increased photosynthetic pigments and activity of antioxidant enzymes that ensured steady photosynthetic rate during Cd stress. MO 16 showed Cd exclusion characteristics when compared with MTU 7029. Photosynthesis performance of MO 16 was not affected by Cd treatments. These findings suggest that photosynthesis influenced decrease in Cd translocation enhanced shoot growth of seedlings during ammonium phosphate-sulfur fertilizer supplementation.

  9. Thermogravimetric control of intermediate compounds in uranium metallurgy; Control termogravimetrico de productos intermedios de la metalurgia del uranio

    Energy Technology Data Exchange (ETDEWEB)

    Gasco Sanchez, L.; Fernandez Cellini, R.

    1959-07-01

    The thermal decomposition of some intermediate compounds in the metallurgy of the uranium as uranium peroxide, ammonium uranate, uranium and ammonium penta-fluoride, uranium tetrafluoride and uranous oxide has been study by means of the Chevenard's thermo balance. Some data on pyrolysis of synthetic mixtures of intermediate compounds which may occasionally appear during the industrial process, are given. Thermogravimetric methods of control are suggested, usable in interesting products in the uranium metallurgy. (Author) 20 refs.

  10. Performance of sulfate-dependent anaerobic ammonium oxidation

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The performance of sulfate-dependent anaerobic ammonium oxidation was studied.The results showed that both SO42-and NH4+ were chemically stable under anaerobic conditions.They did not react with each other in the absence of biological catalyst(sludge).The anaerobic digested sludge cultivated in an anaerobic reactor for three years took on the ability of oxidizing ammonium with sulfate anaero-bically.The average reduction of sulfate and ammonium was 71.67 mg.L-1 and 56.82 mg.L-1 at high concentrations.The reaction between SO42-and NH4+ was difficult,though feasible,due to its low standard Gibbs free energy change.The experiment demonstrated that high substrate concentrations and low oxidation-reduction potential(ORP) may be favourable for the biological reaction.

  11. Performance of sulfate-dependent anaerobic ammo-nium oxidation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lei; ZHENG Ping; HE YuHui; JIN RenCun

    2009-01-01

    The performance of sulfate-dependent anaerobic ammonium oxidation was studied. The results showed that both SO42- and NH4+ were chemically stable under anaerobic conditions. They did not react with each other in the absence of biological catalyst (sludge). The anaerobic digested sludge cultivated in an anaerobic reactor for three years took on the ability of oxidizing ammonium with sulfate anaero-bically. The average reduction of sulfate and ammonium was 71.67 mg.L-1 and 56.82 mg.L-1 at high concentrations.The reaction between SO42- and NH4+ was difficult, though feasible, due to its low standard Gibbs free energy change. The experiment demonstrated that high substrate concentrations and low oxidation-reduction potential (ORP) may be favourable for the biological reaction.

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

    DEFF Research Database (Denmark)

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

    2006-01-01

    The fate and transport of watershed-derived ammonium in a tidal freshwater marsh fringing the nutrient rich Scheldt River, Belgium, was quantified in a whole ecosystem 15N labeling experiment. In late summer (September) we added 15N-NH4+ to the flood water entering a 3477 m2 tidal freshwater marsh...... area, and traced the ammonium processing and retention in four subsequent tide cycles. In this paper we present the results for the water-phase components of the marsh system and compare them to a similar experiment conducted in spring/early summer (May). Changes in concentration and isotopic......, but the absolute ammonium transformation rate was 3 times higher in May. While the marsh surface area was crucial for nitrification in May this was less pronounced in September. Denitrification, on the other hand, appeared more important in September compared to May....

  13. Handling of Ammonium Nitrate Mother-Liquid Radiochemical Production - 13089

    International Nuclear Information System (INIS)

    The aim of the work is to develop a basic technology of decomposition of ammonium nitrate stock solutions produced in radiochemical enterprises engaged in the reprocessing of irradiated nuclear fuel and fabrication of fresh fuel. It was necessary to work out how to conduct a one-step thermal decomposition of ammonium nitrate, select and test the catalysts for this process and to prepare proposals for recycling condensation. Necessary accessories were added to a laboratory equipment installation decomposition of ammonium nitrate. It is tested several types of reducing agents and two types of catalyst to neutralize the nitrogen oxides. It is conducted testing of modes of the process to produce condensation, suitable for use in the conversion of a new technological scheme of production. It is studied the structure of the catalysts before and after their use in a laboratory setting. It is tested the selected catalyst in the optimal range for 48 hours of continuous operation. (authors)

  14. Enrichment culture of marine anaerobic ammonium oxidation (anammox) bacteria

    Institute of Scientific and Technical Information of China (English)

    GUAN Yong-jie

    2016-01-01

    The present study investigates the enrichment of anaerobic ammonium oxidation (anammox) bacteria in the marine environment using sediment samples obtained from the East China Sea and discusses the nitrogen removal efficiency of marine anammox bioreactor. Enrichment of anammox bacteria with simultaneous removal of nitrite and ammonium ions was observed in the Anaerobic Sequencing Batch Reactor under a total nitrogen loading rate of 0.37kg-N m-3day-1. In this study, The nitrogen removal efficiency was up to 80% and the molar-reaction ratio of ammonium, nitrite and nitrate was 1.0:1.22:0.22 which was a little different from a previously reported ratio of 1.0:1.32:0.26 in a freshwater system.

  15. Steady state growth of E. Coli in low ammonium environment

    Science.gov (United States)

    Kim, Minsu; Deris, Barret; Zhang, Zhongge; Hwa, Terry

    2011-03-01

    Ammonium is the preferred nitrogen source for many microorganisms. In medium with low ammonium concentrations, enteric bacteria turn on the nitrogen responsive (ntr) genes to assimilate ammonium. Two proteins in E. coli, Glutamine synthetase (GS) and the Ammonium/methylammonium transporter AmtB play crucial roles in this regard. GS is the major ammonium assimilation enzyme below 1mM of NH4 + . AmtB is an inner membrane protein that transports NH4 + across the cell membrane against a concentration gradient. In order to study ammonium uptake at low NH4 + concentration at neutral pH, we developed a microfluidic flow chamber that maintains a homogenous nutrient environment during the course of exponential cell growth, even at very low concentration of nutrients. Cell growth can be accurately monitored using time-lapse microscopy. We followed steady state growth down to micro-molar range of NH4 + for the wild type and Δ amtB strains. The wild type strain is able to maintain the growth rate from 10mM down to a few uM of NH4 + , while the mutant exhibited reduced growth below ~ 20 ~uM of NH4 + . Simultaneous characterization of the expression levels of GS and AmtB using fluorescence reporters reveals that AmtB is turned on already at 1mM, but contributes to function only below ~ 30 ~uM in the wild-type. Down to ~ 20 ~uM of NH4 + , E.~coli can compensate the loss of AmtB by GS alone.

  16. Laboratory studies of ice formation pathways from ammonium sulfate particles

    Directory of Open Access Journals (Sweden)

    M. E. Wise

    2008-08-01

    Full Text Available Cirrus clouds are composed of ice particles and their formation pathways have been studied extensively in the laboratory. The ability of ammonium sulfate particles to act as nuclei for cirrus clouds has been of particular importance because of their ubiquitous presence in the upper troposphere. The results of past laboratory experiments of homogeneous ice nucleation from ammonium sulfate particles show a wide range of freezing conditions. In the present study, a flow tube apparatus equipped with Fourier transform infrared spectroscopy was used to resolve these discrepancies. It was found that when ammonium sulfate particles were preconditioned at 100% relative humidity (RH prior to experimentation, the particles froze at conditions predicted by the homogeneous ice nucleation model developed by Koop et al. (2000. If the particles were not preconditioned at 100% RH, they froze at warmer temperatures and lower ice saturation ratios than predicted by Koop et al. (2000. In order to determine if a population of effloresced particles affected freezing conditions for particles that were not preconditioned at 100% RH, a series of depositional ice nucleation experiments were carried out on dry ammonium sulfate particles. For freezing temperatures between 215 and 231 K, ice nucleated on the particles at ice saturation ratios (Sice between 1 and 1.05. These conditions are much lower than predicted by Koop et al. (2000 and explain the differences in freezing conditions among preconditioning methods. In similar experiments, Abbatt et al. (2006 hypothesized that a small fraction of effloresced ammonium sulfate particles induced ice nucleation at Sice values lower than expected. The current study confirms the Abbatt et al. (2006 hypothesis and, to our knowledge, is the first study to directly observe ice nucleating onto freely flowing dry ammonium sulfate particles at Sice values approaching unity.

  17. Mutagenic activity of quaternary ammonium salt derivatives of carbohydrates

    Science.gov (United States)

    Sikora, Karol; Woziwodzka, Anna; Piosik, Jacek; Podgórska, Beata

    2016-01-01

    Summary This paper presents a study on a series of quaternary ammonium salt (QAS) derivatives of glucopyranosides with an elongated hydrophobic hydrocarbon chain. The new N-[6-(β-D-glucopyranosyloxy)hexyl]ammonium bromides and their O-acetyl derivatives were analyzed via 1H and 13C NMR spectroscopy. The mutagenic activity of the newly synthesized QAS was investigated using two different techniques: The Vibrio harveyi luminescence assay and the Ames test. The obtained results support previous findings contesting QAS safety and indicate that QAS, specifically pyridinium derivatives, might be mutagenic. PMID:27559394

  18. Effect of peroxodisulfate on uranium leaching with ammonium bicarbonate

    Directory of Open Access Journals (Sweden)

    Nurbek Nurpeisov

    2013-05-01

    Full Text Available In this study, uranium leaching from ore material using acid solution and bicarbonate in a presence peroxodisulfate ion was examined. For experiments two different tips of leaching methods were used: leaching in static and dynamic conditions. The determination of uranium concentrations in product solutions were analyzed by titrimetric (by ammonia vanadate solution method. The maximum yield of uranium leached with ammonium bicarbonate in a presence of ammonium peroxodisulfate (5 g/L was only 33%, which is half the corresponding value obtained by sulfuric acid (65%.

  19. Aerosol isotopic ammonium signatures over the remote Atlantic Ocean

    Science.gov (United States)

    Lin, C. T.; Jickells, T. D.; Baker, A. R.; Marca, A.; Johnson, M. T.

    2016-05-01

    We report aerosol ammonium 15N signatures for samples collected from research cruises on the South Atlantic and Caribbean using a new high sensitivity method. We confirm a pattern of isotopic signals from generally light (δ15N -5 to -10‰), for aerosols with very low (ocean, to generally heavier values (δ15N +5 to +10‰), for aerosols collected in temperate and tropical latitudes and with higher ammonium concentrations (>2  nmol m-3). We discuss whether this reflects a mixing of aerosols from two end-members (polluted continental and remote marine emissions), or isotopic fractionation during aerosol transport.

  20. Determination of Ammonium Ion in Lake Water by Voltammetry

    Institute of Scientific and Technical Information of China (English)

    Wu Yun-hua; Fei Jun-jie; Dang Xue-ping; Hu Sheng-shui

    2004-01-01

    An electroanalytical method for the determination of armonium ion using a platinized platinum electrode is described. Under optimized analytical conditions, the linear range of the calibration graphs for ammonium ion is 3. 0×10(-5)-5.0×10-3 mol·L-1.The Method has been applide to the determination of ammonium ion in lake water samples and recoveries of 100%-103%0 are obtained. The results obtained are found to be in good agreement with spectrophotometric results.

  1. Reuse of ammonium fluoride generated in the uranium hexafluoride conversion; Reutilizacao do fluoreto de amonio gerado na reconversao do hexafluoreto de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Silva Neto, J.B.; Carvalho, E.F. Urano de; Durazzo, M., E-mail: jbsneto@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Riella, H.G [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil)

    2010-07-01

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

  2. 聚硅氧烷季铵盐的合成及应用研究进展%Progress on Preparation and Application of Polysiloxane Quaternary Ammonium Salts

    Institute of Scientific and Technical Information of China (English)

    黄良仙; 肖波; 杨军胜; 安秋凤

    2013-01-01

    Four synthetic methods for preparations of polysiloxane quaternary ammonium salts were summarized , i. e. quaternization reaction of amino silane (amino silicone) with quaternary ammonium reagent, substituted reaction of halogen allcyl silane with tertiary amine, hydrosilylation and quaternization reaction of the hydrogen silicone oil with unsaturated compounds containing active group, and the equilibrium polymerization or condensation reaction of methyl silicone oil and quaternary ammonium salt. The application of the polysiloxane quaternary ammonium salts were introduced in the fabric finishing, daily chemical products, pesticides , sewage treatment and other applications. In the end, the development trends of polysiloxane quaternary ammonium salt were proposed.%阐述了聚硅氧烷季铵盐的4种合成方法:氨基硅烷(油)与季铵化试剂的季铵化反应法、卤烃基硅烷与叔胺的取代反应法、含氢硅油(烷)与含活性基团的不饱和化合物的硅氢加成及季铵化反应法、甲基硅油与氨基硅烷、季铵盐的平衡反应法,介绍了其在织物整理、日化产品、农药、污水处理等方面的应用,并对其发展前景进行了展望.

  3. Bis(tetra-ethyl-ammonium) bis-(hydrogen l-tartrate) l-tartaric acid monohydrate.

    Science.gov (United States)

    Rajalakshmi, M; Indirajith, R; Gopalakrishnan, R; Ramamurthi, K; Stoeckli-Evans, Helen

    2011-06-01

    In the title compound, 2C(8)H(20)N(+)·2C(4)H(5)O(6) (-)·C(4)H(6)O(6)·H(2)O, the presence of the two tetra-ethyl-ammonium cations is balanced by two hydrogen l-tartrate anions. Also present in the asymmetric unit are a mol-ecule of l-tartaric acid and a water mol-ecule. The various components are linked by O-H⋯O hydrogen bonds. In the crystal, two-dimensional networks are formed via O-H⋯O hydrogen bonds and C-H⋯O inter-actions involving the water mol-ecule, the hydrogen l-tartrate anions and the l-tartaric acid mol-ecules. These layers, which stack along [001], are separated by tetra-ethyl-ammonium cations. The latter are also involved in C-H⋯O inter-actions with the anions and the l-tartaric acid and water mol-ecules participating in the two-dimensional network.

  4. 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.

  5. Contact-killing of adhering streptococci by a quaternary ammonium compound incorporated in an acrylic resin

    NARCIS (Netherlands)

    Mei, Li; Ren, Yijin; Loontjens, Ton J. A.; van der Mei, Henny C.; Busscher, Henk J.

    2012-01-01

    Purpose: Acrylates for bonding of joint prostheses and stainless-steel brackets in orthopedics and orthodontics are prone to bacterial adhesion and biofilm formation, respectively, leading to serious infectious complications. Here we describe the preparation of a contact-killing acrylic resin by inc

  6. Lattice variation and thermal parameters of gel grown KDP crystals added with some ammonium compounds

    Indian Academy of Sciences (India)

    T H Freeda; C Mahadevan

    2001-10-01

    Pure and impurity added (with NH4Cl, NH4NO3, NH4H2PO4, and (NH4)2SO4) KDP single crystals were grown by the gel method using silica gels. X-ray diffraction data were collected for powder samples and used for the estimation of lattice variation and thermal parameters like Debye–Waller factor, mean-square amplitude of vibration, Debye temperature and Debye frequency. The thermal parameters do not vary in a particular order with respect to impurity concentration. The results obtained are reported and discussed.

  7. Quaternary ammonium compounds as water channel blockers. Specificity, potency, and site of action.

    NARCIS (Netherlands)

    Detmers, F.J.M.; Groot, B.L. de; Muller, E.M.; Hinton, A.; Konings, I.B.M.; Sze, M.; Flitsch, S.L.; Grubmuller, H.; Deen, P.M.T.

    2006-01-01

    Excessive water uptake through Aquaporins (AQP) can be life-threatening and reversible AQP inhibitors are needed. Here, we determined the specificity, potency, and binding site of tetraethylammonium (TEA) to block Aquaporin water permeability. Using oocytes, externally applied TEA blocked AQP1/AQP2/

  8. Electrical conductivity measurements on gel grown KDP crystals added with some ammonium compounds

    Indian Academy of Sciences (India)

    T H Freeda; C Mahadevan

    2000-08-01

    Pure and impurity added [with NH4Cl, NH4NO3, NH4H2PO4, (NH4)2CO3 and (NH4)2SO4] KDP single crystals were grown by the gel method using silica gels. Electrical conductivity measurements were carried out along both the unique axis and perpendicular directions at various temperatures ranging from 28 to 140°C by the conventional two-probe method. The present study shows that the conductivity in KDP crystals, for all the five dopants considered, increases with the increase in impurity concentration and temperature. Activation energies were also determined and reported.

  9. 75 FR 40729 - Residues of Quaternary Ammonium Compounds, N-Alkyl (C12-14

    Science.gov (United States)

    2010-07-14

    ...) 305-5805. II. Summary of Petitioned-For Exemption In the Federal Register of November 28, 2007 (72 FR... represents the different number of hydrocarbon carbon moieties delineated by different percentages (e.g... chemicals together because variance in the length and conformation of alkyl carbon chains between 12 and...

  10. Determination of ammonium sulphate in ammonia alum by formaldehyde reaction

    Directory of Open Access Journals (Sweden)

    Amir Chand

    1962-01-01

    Full Text Available Existing methods for the estimation of ammonium salts in presence of hydrolysable salts have been reviewed. A new titrimetric method utilizing formaldehyde and potassium fluoride is described for its estimation in presence of aluminium sulphate. The method is accurate and rapid for routine analysis.

  11. Treating leachate mixture with anaerobic ammonium oxidation technology

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong-guo; ZHOU Shao-qi

    2006-01-01

    Large amounts of ammonium and a low content of biodegradable chemical oxygen demand(COD) are contained in leachate from aged landfills, together with the effluent containing high concentration of nitric nitrogen after biochemical treatment.Treatment effect of anaerobic ammonium oxidation (anammox) process on the mixture of the leachate and its biochemical effluent was investigated. The results show that the average removal efficiencies of ammonium, nitric nitrogen and total nitrogen are 87.51%,74.95% and 79.59%, respectively, corresponding to the average ratio of removed nitric nitrogen to ammonium, i.e. 1.14 during the steady phase of anammox activity. The mean removal efficiency of COD is only 24.01% during the experimental period. The demand of total phosphorous for the anammox process is unobvious. Especially, the alkalinity and pH value of the effluent are close to those of the influent during the steady phase of anammox activity. In addition, it is demonstrated that the status of the anammox bioreactor can be indicated by the alkalinity and pH value during the course of the experiment. The anammox bioreactor has shown potential for nitrogen removal in the leachate mixture. However, COD and total phosphorous in the leachate mixture need further treatment for removal efficiencies of COD and total phosphorous are not good in the anammox bioreactor.

  12. Characterization of ammonium polyuranate powders from a continuous precipitator

    Energy Technology Data Exchange (ETDEWEB)

    Oolman, T.

    1979-01-01

    Ammonium polyuranate powders produced in a continuous, well-mixed precipitator were characterized by means of electron microscopy. The powders were qualitatively analyzed with the scanning electron microscope and the elementary crystallites were quantivatively analyzed with the transmission electron microscope. The results were fit to a kinetic theory of continuous precipitation. A phase analysis was also preformed by x-ray powder diffraction.

  13. Carboxylates and the uptake of ammonium by excised maize roots

    NARCIS (Netherlands)

    Breteler, H.

    1975-01-01

    The effect of carboxylates (organic acid anions) on NH 4 uptake was studied by changing the carboxylate level of roots prior to uptake experi ments. Succinate was the most effective stimulator of ammonium uptake. The oxocarboxylates (α-oxoglutarate, oxaloacetate and

  14. Fate of N from Green Manures and Ammonium Sulfate

    Institute of Scientific and Technical Information of China (English)

    SHISHU-LIAN; WENQI-XIAO; 等

    1991-01-01

    By means of 15N tracer technique the fate of N in ammonium sulfate,milk vetch,sesbania and azolla,and the availability of their residual N were studied in a microplot experiment.Results showed that a) at the end of the first crop of early rice,both plant recovery and loss of N from ammonium sulfate were the highest whereas those from azolla were the lowest with those from milk vetch and sesbania in between;the sequence was reversed in terms of recovery of N in soil;the net residual N from ammonium sulfate was very low,about 1/7-1/4 of that from green manures,indicating that chemical N fertilizer contributes little to the soil N reserve;b) plant recovery of the residual N was low and it did not always decrease with time;the total plant recovery (from the second to the fifth crops) of the residual N from various test fertilizers was only 8-11% of the total N originally applied;c) the plant recovery of the residual N from ammonium sulfate was the highest,followed by those from milk vetch and sesbania,and that from azolla was the lowest,no matter in which cropping season (from the second to the fifth);N availability ratio showed the same trend,indicating that chemical N fertilizer helps renovate soil organic N,maintain and increase availability of soil N.

  15. Synthetic receptors for ammonium ions using dynamic combinatorial chemistry

    NARCIS (Netherlands)

    Hamieh, Saleh

    2015-01-01

    The general topic of this dissertation is the development of synthetic receptors for organic ammonium ions in near physiological conditions using disulfide dynamic combinatorial chemistry (DCC). Chapter 1 explains the importance of this development and the associated difficulties when using the conv

  16. Characterization of ammonium polyuranate powders from a continuous precipitator

    International Nuclear Information System (INIS)

    Ammonium polyuranate powders produced in a continuous, well-mixed precipitator were characterized by means of electron microscopy. The powders were qualitatively analyzed with the scanning electron microscope and the elementary crystallites were quantivatively analyzed with the transmission electron microscope. The results were fit to a kinetic theory of continuous precipitation. A phase analysis was also preformed by x-ray powder diffraction

  17. Growth features of ammonium hydrogen -tartrate single crystals

    Indian Academy of Sciences (India)

    G Sajeevkumar; R Raveendran; B S Remadevi; Alexander Varghese Vaidyan

    2004-08-01

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

  18. Ammonium dinitramide (ADN)-Prilling, coating, and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Heintz, Thomas; Pontius, Heike; Aniol, Jasmin; Birke, Christoph; Leisinger, Karlfred; Reinhard, Werner [Fraunhofer-Institut Chemische Technologie ICT, Pfinztal (Germany)

    2009-06-15

    Ammonium dinitramide (ADN) is the promising oxidizer, which is expected to be applied, e.g., in solid rocket propellants. The manufacturing of spherical ADN particles (the so-called ADN-Prills) with useful morphology and reproducible quality is realized by means of the emulsion crystallization process. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  19. Increase of water resistance of ammonium nitrate explosives

    Directory of Open Access Journals (Sweden)

    Zulkhair Mansurov

    2012-03-01

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

  20. Profiling the origin of ammonium nitrate: proof-of-principle

    NARCIS (Netherlands)

    Carol-Visser, J.; Farmache, M.A.; Heijden, A.E.D.M. van der

    2011-01-01

    In many Improvised Explosive Devices (IEDs) the main charge consists of ammonium nitrate (AN). For forensic reasons, screening for the origin of AN is of importance. By assessing specifi c characteristics, diff erent AN batches can be profi led, in this way providing extra information which could le

  1. Simultaneous Nitrite-Dependent Anaerobic Methane and Ammonium Oxidation Processes

    NARCIS (Netherlands)

    Luesken, F.A.; Sánchez. J.; Van Alen, T.A.; Sanabria, J.; Op den Camp, H.J.; Jetten, M.S.; Kartal, B.

    2011-01-01

    itrite-dependent anaerobic oxidation of methane (n-damo) and ammonium (anammox) are two recently discovered processes in the nitrogen cycle that are catalyzed by n-damo bacteria, including "Candidatus Methylomirabilis oxyfera," and anammox bacteria, respectively. The feasibility of coculturing anamm

  2. Crystal structure of the heptamolybdate(VI) (paramolybdate) ion, [Mo7O24]6-, in the ammonium and potassium tetrahydrate salts

    Science.gov (United States)

    Evans, H.T.; Gatehouse, B.M.; Leverett, P.

    1975-01-01

    The crystal structures of the isomorphous salts MI6 [Mo7O24],4H2O (M = NH4 or K) have been refined by three-dimensional X-ray diffraction methods. Unit cell dimensions of these monoclinic compounds, space group P21/C with Z = 4, are, ammonium salt: a = 8.3934 ?? 0.0008, b = 36.1703 ?? 0.0045, c = 10.4715 ?? 0.0011 A??, ?? = 115.958?? ?? 0.008??; and potassium salt: a = 8.15 ?? 0.02, b = 35.68 ?? 0.1, c = 10.30 ?? 0.02 A??, ?? = 115.2?? ?? 02??. By use of multiple Weissenberg patterns, 8197 intensity data (Mo-K?? radiation) for the ammonium compound and 2178 (Cu-K?? radiation) for the potassium compound were estimated visually and used to test and refine Lindqvist's proposed structure in the space group P21/c. Lindqvist's structure was confirmed and the full matrix least-squares isotropic refinement led to R 0.076 (ammonium) 0.120 (potassium), with direct unambiguous location of the cations and water molecules in the potassium compound.

  3. Effect of Triethanolamine and Benzaldehyde on the Storage Stability of Polystyrene- Ammonium Perchlorate Propellant

    Directory of Open Access Journals (Sweden)

    K. Kishore

    1986-10-01

    Full Text Available The effect of triethanolamine and benzaldehyde on the stability of polystyrene has been studied by dynamic thermogravimetry (TG. Slower decomposition of polymer in the presence of these compounds indicates their inhibiting ability on the oxidation of the polymer. The burning rate measurements of polystyrene (PS/ammonium perchlorate (AP propellants at ambient temperature and pressure shows an increase with the storage time. The percentage change in the burning rate of the propellants containing aldehyde and amine is less during the ageing which indicates the increased stability of the propellants. The safe-life time of the propellants for the ballistic stability has been calculated from the activation energy for the ageing process using an Arrhenius type equation. The safe-life of the propellants containing triethanolamine and benzaldehyde is more than the neat propellant.

  4. Ammonium removal from high-strength aqueous solutions by Australian zeolite

    DEFF Research Database (Denmark)

    Wijesinghe, D. Thushari N; Dassanayake, Kithsiri B.; Sommer, Sven G.;

    2016-01-01

    . Increased retention time and temperature generally had a positive impact on adsorption. Freundlich model fitted well with adsorption process of Australian natural zeolites; however, Langmuir model had best fitted for the adsorption process of sodium (Na+) treated zeolites. NaCl treatment increased the NH4...... to its high adsorption capacity of ammonium (NH4 +). However, detailed investigations on NH4 + adsorption and ion exchange capacities of Australian natural zeolites are rare, particularly under higher NH4 + concentrations in the medium. Therefore, this study was conducted to determine NH4 + adsorption...... characteristics of Australian natural zeolites at high NH4 + concentrations with and without other chemical compounds in an aqueous solution. Results showed that initial NH4 + concentration, temperature, reaction time, and pH of the solution had significant effects on NH4 + adsorption capacity of zeolite...

  5. STUDIES ON SYNTHESIS AND CHARACTER OF INORGANIC ION EXCHANGER TITANIUM PHOSPHATE—AMMONIUM TUNGSTOPHOSPHATE

    Institute of Scientific and Technical Information of China (English)

    YuXintian; SunZhaoxiang

    1998-01-01

    In this paper,a new complex inorganic ion exchanger Titanium Phosphate-Ammonium Tungstophosphate(abbreviated as Tip-AWP) was synthesized,whose exchange character and chemical structure were studied.This compound exhibits high exchange capacity and selectivity for Cs+,its exchange capacity accains 0.95 mmol/g in the medium of 0.1mol/L HNO3,and which almost doesn′t change in the 1AW imitated waste solution.There are no change in exchange capacity and structute after several times of exchanging,eluting,regenerating,which is of great importance to the separation and uptaking of radio-nuclides.Further more,this exchanger has good thermal and redioactive stability.

  6. Perfluorinated quaternary ammonium salts of polyoxometalate anions: Fluorous biphasic oxidation catalysis with and without fluorous solvents

    Energy Technology Data Exchange (ETDEWEB)

    Maayan, Galia; Fish, Richard H.; Neumann, Ronny

    2003-05-28

    Perfluorinated quaternary ammonium cations, [CF{sub 3}(CF{sub 2}){sub 7}(CH{sub 2}){sub 3}]{sub 3}CH{sub 3}N{sup +} (RFN{sup +}), were synthesized and used as counter cations for the [WZnM{sub 2}(H{sub 2}O){sub 2}(ZnW{sub 9}O{sub 34}){sub 2}]{sup 12-} (M = Mn(II), Zn(II)), polyoxometalate. The (RFN{sup +}){sub 12}[WZnM{sub 2}(H{sub 2}O){sub 2}(ZnW9O{sub 34}){sub 2}] compounds were fluorous biphasic catalysts for alcohol and alkenol oxidation, and alkene epoxidation with aqueous hydrogen peroxide. Reaction protocols with or without a fluorous solvent were tested. The catalytic activity and selectivity was affected both by the hydrophobicity of the solvent and the substrate.

  7. Inhibition of anaerobic ammonium oxidizing (anammox) enrichment cultures by substrates, metabolites and common wastewater constituents.

    Science.gov (United States)

    Carvajal-Arroyo, José M; Sun, Wenjie; Sierra-Alvarez, Reyes; Field, Jim A

    2013-03-01

    Anaerobic ammonium oxidation (anammox) is an emerging technology for nitrogen removal that provides a more environmentally sustainable and cost effective alternative compared to conventional biological treatment methods. The objective of this study was to investigate the inhibitory impact of anammox substrates, metabolites and common wastewater constituents on the microbial activity of two different anammox enrichment cultures (suspended and granular), both dominated by bacteria from the genus Brocadia. Inhibition was evaluated in batch assays by comparing the N(2) production rates in the absence or presence of each compound supplied in a range of concentrations. The optimal pH was 7.5 and 7.3 for the suspended and granular enrichment cultures, respectively. Among the substrates or products, ammonium and nitrate caused low to moderate inhibition, whereas nitrite caused almost complete inhibition at concentrations higher than 15 mM. The intermediate, hydrazine, either stimulated or caused low inhibition of anammox activity up to 3mM. Of the common constituents in wastewater, hydrogen sulfide was the most severe inhibitor, with 50% inhibitory concentrations (IC(50)) as low as 0.03 mM undissociated H(2)S. Dissolved O(2) showed moderate inhibition (IC(50)=2.3-3.8 mg L(-1)). In contrast, phosphate and salinity (NaCl) posed very low inhibition. The suspended- and granular anammox enrichment cultures had similar patterns of response to the various inhibitory stresses with the exception of phosphate. The findings of this study provide comprehensive insights on the tolerance of the anammox process to a wide variety of potential inhibiting compounds.

  8. Metabolic responses of Saccharomyces cerevisiae to valine and ammonium pulses during four-stage continuous wine fermentations.

    Science.gov (United States)

    Clement, T; Perez, M; Mouret, J R; Sanchez, I; Sablayrolles, J M; Camarasa, C

    2013-04-01

    Nitrogen supplementation, which is widely used in winemaking to improve fermentation kinetics, also affects the products of fermentation, including volatile compounds. However, the mechanisms underlying the metabolic response of yeast to nitrogen additions remain unclear. We studied the consequences for Saccharomyces cerevisiae metabolism of valine and ammonium pulses during the stationary phase of four-stage continuous fermentation (FSCF). This culture technique provides cells at steady state similar to that of the stationary phase of batch wine fermentation. Thus, the FSCF device is an appropriate and reliable tool for individual analysis of the metabolic rerouting associated with nutrient additions, in isolation from the continuous evolution of the environment in batch processes. Nitrogen additions, irrespective of the nitrogen-containing compound added, substantially modified the formation of fermentation metabolites, including glycerol, succinate, isoamyl alcohol, propanol, and ethyl esters. This flux redistribution, fulfilling the requirements for precursors of amino acids, was consistent with increased protein synthesis resulting from increased nitrogen availability. Valine pulses, less efficient than ammonium addition in increasing the fermentation rate, were followed by a massive conversion of this amino acid in isobutanol and isobutyl acetate through the Ehrlich pathway. However, additional routes were involved in valine assimilation when added in stationary phase. Overall, we found that particular metabolic changes may be triggered according to the nature of the amino acid supplied, in addition to the common response. Both these shared and specific modifications should be considered when designing strategies to modulate the production of volatile compounds, a current challenge for winemakers.

  9. Chemiluminescent method for detection of eutrophication sources by estimation of organic amino nitrogen and ammonium in water.

    Science.gov (United States)

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

    2006-11-01

    An automatic method has been developed for the estimation of organic amino nitrogen (CH2-NH) and ammonium in water samples. We propose a continuous flow system in which nitrogen compounds react with hypochlorite reagent to produce chloramines. Subsequently, the mixture is mixed with luminol, generating a chemiluminescence signal. The signal emission at 425 nm, registered as a function of time, decreases as nitrogen concentration increases, due to the decrease on hypochlorite concentration. A large number of nitrogen compounds have been assayed and their sensitivities compared, in milligrams per liter nitrogen. The ammonium calibration graph, expressed as N, can be used for most of the assayed compounds. The linear interval was 0.24-4 mg L(-1) N, with the detection limit 0.07 mg L(-1) N. The chemiluminescence method was applied to the analysis of several kinds of real water samples, natural, lake, irrigation ditch, fountain, residual, and seawater in order to detect possible sources of eutrophication. The accuracy (% relative error) and precision were satisfactory, with mean values of 5 +/- 4 and 3 +/- 2, respectively. This procedure has been used to estimate nitrogen content in samples before and after Kjeldahl treatment. In the same samples, the N found for the untreated samples provided a good estimation of the N Kjeldahl. Sixty samples per hour can be analyzed, and the procedure can also be used for in situ monitoring.

  10. Structural, thermal behaviour and vibrational study of a new mixed cesium-ammonium tellurate

    Indian Academy of Sciences (India)

    Wafa Ben Aribia; Makki Abdelmouleh; Van Der Lee; Ahlem Kabadou

    2012-03-01

    Synthesis, crystal structure, thermal characterization, FTIR and Raman measurements are given for a new mixed compound cesium-ammonium tellurate. X-ray study showed that the [Cs0.92(NH4)0.08]2TeCl4Br2 compound crystallizes in the tetragonal space group P4/mnc, with a = 7.452 (1) Å, c = 10.544 (3) Å and Z = 2. The refinement converged at room temperature to = 0.093 and = 0.076. The structure is considered as isolated octahedral TeCl4Br$^{2−}_{2}$. These anions show a 4° rotation around the fourfold axis against the cubic arrangement of the K2PtCI6 type structure. The monovalent cations (Cs+/NH$^{+}_{4}$) are located between the octahedra ensuring the stability of the structure by ionic and hydrogen bonding contacts: Cs…Cl/Br and N-H$\\ldots\\ldots$Cl/Br. A DTA/TGA experiment at high temperature reveals one endothermic peak at 780K for this compound. At low temperature a transition from phase I to phase II was detected at 213K by DSC. This transition, confirmed by Raman analysis, can be attributed to an order-disorder phase transition.

  11. Assessing the ammonium nitrate formation regime in the Paris megacity and its representation in the CHIMERE model

    Science.gov (United States)

    Petetin, Hervé; Sciare, Jean; Beekmann, Matthias; Sanchez, Olivier; Rosso, Amandine; Denier van der Gon, Hugo

    2014-05-01

    Ammonium nitrates significantly contribute to the fine particulate matter load, in particular in the Paris agglomeration where two measurement campaigns, PARTICULES and FRANCIPOL, have recently made available a large database on this compound and its gaseous precursors, nitric acid and ammonia. These new observations give the opportunity (for the first time in France) to assess the ammonium nitrate formation regime (in terms of limited species) as well as the ability of the CHIMERE chemistry-transport model to simulate each species and to reproduce in fine the observed regime. Quite satisfactory results are obtained on nitrates, mainly due to a significant contribution of imports from outside the agglomeration. However, significant biases affect both gaseous precursors. Various uncertainty sources are discussed, including those relative to ammonia trafic and agricultural emissions, thermodynamic equilibria or oxidative capacity of the atmosphere. Despite these errors, CHIMERE manages to simulate a HNO3-limited regime, in agreement with observations, at least at the daily scale. This study especially confirms that further work on the OH radical characterization in the CHIMERE model and agricultural ammonia emissions are required to improve the simulation of the ammonium nitrate formation regime.

  12. Biodegradability and aquatic toxicity of quaternary ammonium-based gemini surfactants: Effect of the spacer on their ecological properties.

    Science.gov (United States)

    Garcia, M Teresa; Kaczerewska, Olga; Ribosa, Isabel; Brycki, Bogumił; Materna, Paulina; Drgas, Małgorzata

    2016-07-01

    Aerobic biodegradability and aquatic toxicity of five types of quaternary ammonium-based gemini surfactants have been examined. The effect of the spacer structure and the head group polarity on the ecological properties of a series of dimeric dodecyl ammonium surfactants has been investigated. Standard tests for ready biodegradability assessment (OECD 310) were conducted for C12 alkyl chain gemini surfactants containing oxygen, nitrogen or a benzene ring in the spacer linkage and/or a hydroxyethyl group attached to the nitrogen atom of the head groups. According to the results obtained, the gemini surfactants examined cannot be considered as readily biodegradable compounds. The negligible biotransformation of the gemini surfactants under the standard biodegradation test conditions was found to be due to their toxic effects on the microbial population responsible for aerobic biodegradation. Aquatic toxicity of gemini surfactants was evaluated against Daphnia magna. The acute toxicity values to Daphnia magna, IC50 at 48 h exposure, ranged from 0.6 to 1 mg/L. On the basis of these values, the gemini surfactants tested should be classified as toxic or very toxic to the aquatic environment. However, the dimeric quaternary ammonium-based surfactants examined result to be less toxic than their corresponding monomeric analogs. Nevertheless the aquatic toxicity of these gemini surfactants can be reduced by increasing the molecule hydrophilicity by adding a heteroatom to the spacer or a hydroxyethyl group to the polar head groups. PMID:27045632

  13. 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.

  14. 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

  15. 76 FR 39847 - Solid Fertilizer Grade Ammonium Nitrate From the Russian Federation; Final Results of the...

    Science.gov (United States)

    2011-07-07

    ...: Solid Fertilizer Grade Ammonium Nitrate From the Russian Federation, 64 FR 45236 (August 19, 1999). On... Fertilizer Grade Ammonium Nitrate From the Russian Federation, 65 FR 42669 (July 11, 2000) (``Final... International Trade Administration Solid Fertilizer Grade Ammonium Nitrate From the Russian Federation;...

  16. 77 FR 65532 - Solid Fertilizer Grade Ammonium Nitrate From the Russian Federation: Notice of Rescission of...

    Science.gov (United States)

    2012-10-29

    ... International Trade Administration Solid Fertilizer Grade Ammonium Nitrate From the Russian Federation: Notice... the antidumping duty order on solid fertilizer grade ammonium nitrate (ammonium nitrate) from the... Nitrate from Russia: Correction to Notice of Opportunity to Request Administrative Review, 77 FR...

  17. 40 CFR 721.10100 - Dialkyl dimethyl ammonium carbonate (2:1) (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Dialkyl dimethyl ammonium carbonate (2... Specific Chemical Substances § 721.10100 Dialkyl dimethyl ammonium carbonate (2:1) (generic). (a) Chemical... as dialkyl dimethyl ammonium carbonate (2:1) (PMN P-03-716) is subject to reporting under...

  18. Anaerobic ammonium oxidation, denitrification and dissimilatory nitrate reduction to ammonium in the East China Sea sediment

    Directory of Open Access Journals (Sweden)

    G. D. Song

    2013-03-01

    Full Text Available Benthic nitrogen transformation pathways were investigated in the sediment of the East China Sea in June of 2010 using the 15N isotope pairing technique. Slurry incubations indicated that denitrification, anammox and dissimilatory nitrate reduction to ammonium (DNRA as well as nitrate release by nitrate storing organisms occurred in the East China Sea sediments. These four processes did not exist independently, the nitrate release therefore diluted the 15N labeling fraction of NO3−, a part of the 15NH4+ derived from DNRA also formed 30N2 via anammox. Therefore current methods of rate calculations led to over and underestimations of anammox and denitrification respectively. Following the procedure outlined in Thampdrup and Dalsgaard (2002, denitrification rates were slightly underestimated by on average 6% without regard to the effect of nitrate release, while this underestimation could be counteracted by the presence of DNRA. On the contrary, anammox rates calculated from 15NO3− experiment were significantly overestimated by 42% without considering nitrate release. In our study this overestimation could only be compensated 14% by taking DNRA into consideration. In a parallel experiment amended with 15NH4+ + 14NO3−, anammox rates were not significantly influenced by DNRA due to the high background of 15NH4+ addition. Excluding measurements in which bioirrigation was present, integrated denitrification rates decreased from 10 to 4 mmol N m−2 d−1 with water depth, while integrated anammox rates increased from 1.5 to 4.0 mmol N m−2 d−1. Consequently, the relative contribution of anammox to the total N-loss increased from 13% at the shallowest site near the Changjiang estuary to 50% at the deepest site on the outer shelf. This study represents the first time in which anammox has been demonstrated to play a significant role in benthic nitrogen cycling in the East China Sea sediment, especially on the outer shelf. N

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

    Directory of Open Access Journals (Sweden)

    Loussouarn C.

    2006-11-01

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

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

    Directory of Open Access Journals (Sweden)

    Dominic Thibeault

    2010-05-01

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

  1. Thermal stability assessment of anti-explosive ammonium nitrate

    Institute of Scientific and Technical Information of China (English)

    Lijin Shen; Xuguang Wang

    2005-01-01

    The explosivity experiment of anti-explosive ammonium nitrate (AEAN) shows that the explosive characteristic of AEAN is eliminated. The adiabatic decompositions of ammonium nitrate and AEAN were investigated with an accelerating rate calorimeter (ARC). The curves of thermal decomposition temperature and pressure versus time, self-heating rate and pressure versus temperature for two systems were obtained. The kinetic parameters such as apparent activation energy and pre-exponential factor were calculated.The safety of AEAN was analyzed. It was indicated that AEAN has a higher thermal stability than AN. At the same time, it can be shown that the elimination of its explosive characteristic is due to the improvement on the thermal stability of AEAN.

  2. EXCHANGE ADSORPTION EQUILIBRIA OF AMMONIUM ON CATION-VERMICULITE MINERALS

    Institute of Scientific and Technical Information of China (English)

    GUO Yaping; XIE Lianwu; WU Xiaofu

    2006-01-01

    Experiment was designed under different pH and temperature conditions to analysis the NH4+ exchange capacity of Na+-vermiculite, Ca2+-vermiculite and Mg2+-vermiculite clay minerals pre-treated using NaCl, CaCl2 and MgCl2 solutions respectively. The results indicated that the exchange reactions occurred most rapidly at the proceeding 80 minutes and approached to equilibrium by about 120 minutes. The exchange quantity of ammonium on the vermiculite (at initial ammonium concentration of 673mg/L ) varied with pH with a peak value of 28.36mg/g on Na+-vermiculite, 23.01mg/g on Ca2+-vermiculite, 20.14mg/g on Mg2+-vermiculite, 18.04mg/g on natural vermiculite at pH 7. The exchange and adsorption isotherm of NH4+ on cation-vermiculite can be described by Langmuir equation.

  3. Kinetic study of uranium residue dissolution in ammonium carbonate media

    International Nuclear Information System (INIS)

    The purpose of this study was to determine the kinetics of the dissolution of a uranium residue in ammonium carbonate media. The residue is generated in the production of medical isotopes. The effects of parameters, such as varying peroxide and carbonate concentrations, dissolution time as well as temperature on the extraction rate have been separately studied. Results indicate complete dissolution of the residue at 60 deg C, after 30 min, in ammonium carbonate solution enriched with hydrogen peroxide. The yield and rate of uranium extraction were found to increase as a function of both temperature, in the range of 25-60 deg C, and hydrogen peroxide concentration. The extraction process was governed by chemical reaction as the activation energy was found to be 45.5 kJ/mol. The order of reaction with respect to uranium concentration was found to be approximately first order. (author)

  4. Anaerobic ammonium oxidation in a bioreactor treating slaughterhouse wastewater

    Directory of Open Access Journals (Sweden)

    V. Reginatto

    2005-12-01

    Full Text Available Ammonium oxidation was thought to be an exclusively aerobic process; however, as recently described in the literature, it is also possible under anaerobic conditions and this process was named ANAMMOX. This work describes the operation of a system consisting of a denitrifying reactor coupled to a nitrifying reactor used for removal of nitrogen from slaughterhouse wastewater. During operation of the denitrifying reactor an average nitrogen ammonium removal rate of 50 mg/Ld was observed. This biomass was used to seed a second reactor, operated in repeated fed batch mode, fed with synthetic medium specific to the growth of bacteria responsible for the ANAMMOX process. The nitrogen loading rate varied between 33 and 67 mgN/Ld and average nitrogen removal was 95% and 40%, respectively. Results of fluorescence in situ hybridization (FISH confirmed the presence of anammox-like microorganisms in the enriched biomass.

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

    Directory of Open Access Journals (Sweden)

    Yvgenij eYanovsky

    2012-04-01

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

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

    Science.gov (United States)

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

    2016-04-01

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

  7. Nitrogen loss by anaerobic oxidation of ammonium in rice rhizosphere

    OpenAIRE

    Nie, San'an; Li, Hu; Yang, Xiaoru; Zhang, Zhaoji; Weng, Bosen; Huang, Fuyi; Zhu, Gui-Bing; Zhu, Yong-Guan

    2015-01-01

    Anaerobic oxidation of ammonium (anammox) is recognized as an important process for nitrogen (N) cycling, yet its role in agricultural ecosystems, which are intensively fertilized, remains unclear. In this study, we investigated the presence, activity, functional gene abundance and role of anammox bacteria in rhizosphere and non-rhizosphere paddy soils using catalyzed reporter deposition–fluorescence in situ hybridization, isotope-tracing technique, quantitative PCR assay and 16S rRNA gene cl...

  8. Recovering germanium from coal ash by chlorination with ammonium chloride

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new process of enriching germanium from coal ash was developed. The process involves in mixing the coal ash and ammonium chloride and then roasting the mixture to produce germanium chloride that is then absorbed by dilute hydrochloric acid and hydrolyzed to germanium oxide. The germanium recovery reached to 80.2% at the optimum condition: mass ratio of NH4Cl/coal ash is 0.15, roasting temperature 400℃ and roasting time 90 min.

  9. Ammonium Uptake by Phytoplankton Regulates Nitrification in the Sunlit Ocean

    OpenAIRE

    Smith, Jason M.; Chavez, Francisco P.; Francis, Christopher A.

    2014-01-01

    Nitrification, the microbial oxidation of ammonium to nitrate, is a central part of the nitrogen cycle. In the ocean's surface layer, the process alters the distribution of inorganic nitrogen species available to phytoplankton and produces nitrous oxide. A widely held idea among oceanographers is that nitrification is inhibited by light in the ocean. However, recent evidence that the primary organisms involved in nitrification, the ammonia-oxidizing archaea (AOA), are present and active throu...

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

    Science.gov (United States)

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

    2016-08-01

    Over the last decades, production of microalgae and cyanobacteria has been developed for several applications, including novel foods, cosmetic ingredients and more recently biofuel. The sustainability of these promising developments can be hindered by some constraints, such as water and nutrient footprints. This review surveys data on N2-fixing cyanobacteria for biomass production and ways to induce and improve the excretion of ammonium within cultures under aerobic conditions. The nitrogenase complex is oxygen sensitive. Nevertheless, nitrogen fixation occurs under oxic conditions due to cyanobacteria-specific characteristics. For instance, in some cyanobacteria, the vegetative cell differentiation in heterocyts provides a well-adapted anaerobic microenvironment for nitrogenase protection. Therefore, cell cultures of oxygenic cyanobacteria have been grown in laboratory and pilot photobioreactors (Dasgupta et al., 2010; Fontes et al., 1987; Moreno et al., 2003; Nayak & Das, 2013). Biomass production under diazotrophic conditions has been shown to be controlled by environmental factors such as light intensity, temperature, aeration rate, and inorganic carbon concentration, also, more specifically, by the concentration of dissolved oxygen in the culture medium. Currently, there is little information regarding the production of extracellular ammonium by heterocytous cyanobacteria. This review compares the available data on maximum ammonium concentrations and analyses the specific rate production in cultures grown as free or immobilized filamentous cyanobacteria. Extracellular production of ammonium could be coupled, as suggested by recent research on non-diazotrophic cyanobacteria, to that of other high value metabolites. There is little information available regarding the possibility for using diazotrophic cyanobacteria as cellular factories may be in regard of the constraints due to nitrogen fixation. PMID:25613641

  11. Hibiscus sabdariffa Affects Ammonium Chloride-Induced Hyperammonemic Rats

    OpenAIRE

    Subramanian, P.; M. Mohamed Essa

    2007-01-01

    Hibiscus sabdariffa (HS) is an edible medicinal plant, indigenous to India, China and Thailand and is used in Ayurveda and traditional medicine. Alcoholic extract of HS leaves (HSEt) was studied for its anti-hyperammonemic and antioxidant effects in brain tissues of ammonium chloride-induced hyperammonemic rats. Oral administration of HSEt (250 mg kg−1 body weight) significantly normalizes the levels of ammonia, urea, uric acid, creatinine and non-protein nitrogen in the blood. HSEt significa...

  12. Subsurface ammonium maxima in northern Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

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

    . Inorganic phosphate was determined by the method of Murphy & Riley (1962), nitrite by the method of Bendschneider & Robinson (1952) and nitrate by the method of Morris & Riley (1963) as modified by Grasshoff (1964). Ammonium was determined by indophenol.... Further, its distribution in the water column showed no definite vertical trend as reported earlier in the other open oceans (Menzel & Spaeth, 1962; Sagi, 1966). However, in the northern Bay of Bengal two prominent maxima, one in the euphotic zone near...

  13. Alicyclic ammonium ionic liquids as lithium battery electrolytes A review

    OpenAIRE

    Puga, A.V.

    2013-01-01

    Ionic liquids are reasonable alternatives to electrolytes used in energy storage devices, such as lithium batteries, both lithium-ion and lithium-metal, given the safety advantages they provide. This is due to the favourable properties they often possess, mainly non­flammability and non­volatility. Candidates with alicyclic ammonium cations exhibit high electrochemical stabilities, especially towards lithium, a unique feature which enables the fabrication of reversible lithium-metal batteries...

  14. Nitrogen addition regulates soil nematode community composition through ammonium suppression.

    Directory of Open Access Journals (Sweden)

    Cunzheng Wei

    Full Text Available Nitrogen (N enrichment resulting from anthropogenic activities has greatly changed the composition and functioning of soil communities. Nematodes are one of the most abundant and diverse groups of soil organisms, and they occupy key trophic positions in the soil detritus food web. Nematodes have therefore been proposed as useful indicators for shifts in soil ecosystem functioning under N enrichment. Here, we monitored temporal dynamics of the soil nematode community using a multi-level N addition experiment in an Inner Mongolia grassland. Measurements were made three years after the start of the experiment. We used structural equation modeling (SEM to explore the mechanisms regulating nematode responses to N enrichment. Across the N enrichment gradient, significant reductions in total nematode abundance, diversity (H' and taxonomic richness, maturity index (MI, and the abundance of root herbivores, fungivores and omnivores-predators were found in August. Root herbivores recovered in September, contributing to the temporal variation of total nematode abundance across the N gradient. Bacterivores showed a hump-shaped relationship with N addition rate, both in August and September. Ammonium concentration was negatively correlated with the abundance of total and herbivorous nematodes in August, but not in September. Ammonium suppression explained 61% of the variation in nematode richness and 43% of the variation in nematode trophic group composition. Ammonium toxicity may occur when herbivorous nematodes feed on root fluid, providing a possible explanation for the negative relationship between herbivorous nematodes and ammonium concentration in August. We found a significantly positive relationship between fungivores and fungal phospholipid fatty acids (PLFA, suggesting bottom-up control of fungivores. No such relationship was found between bacterivorous nematodes and bacterial PLFA. Our findings contribute to the understanding of effects of N

  15. Energetic Compounds for Future Space Applications

    Science.gov (United States)

    Davenas, A.; Jacob, G.; Longevialle, Y.; Pérut, C.

    2004-10-01

    The need for new rocket propellants to improve or replace those in use today has led during the past ten years to studies of various, ancient or relatively new, energetic ingredients. The most often mentioned compounds for solid propellants are ADN (ammonium dinitramide), the nitramines RDX and HMX, HNIW (hexanitro hexaaza isowurtzitane), HNF (hydrazinum nitroformate), GAP (glycidyl azide polymer), and high nitrogen compounds. ADN, HNF, HAN (hydroxylammonium nitrate) are mentioned as possible ingredients in liquid mono and bi propellants for the future. A review of the work being conducted in the development and testing of the candidate propellants as well as an analysis of the general constraints of the industrial use and handling of these propellants and of their basic ingredients allows for a first tentative selection of the most promising ingredients. The possible synthesis routes, main characteristics, production and cost perspectives of these compounds are summarized and discussed.

  16. Study of stripping cristallization processus of AUC with ammonium carbonate

    International Nuclear Information System (INIS)

    This study is concerned with direct crystallization of ammonium uranyl carbonate (AUC) from a uranium loaded organic phase (30% TBP in kerosene), with ammonium carbonate (NH4)2CO3. The effects of operating conditions ((NH4)2CO3 concentration, flow-ratio, residence time, temperature) on the physical properties of AUC crystals (particle size distribution, specific surface, density...) are reported. All products were identified (both by chemical analysis, X-Ray diffraction) as being ammonium uranyl carbonate crystals (AUC). The results show that a high phase ratio and (NH4)2CO3 concentration favor the formation of fine AUC grains and aggregates. This is due mainly to the high concentration of NH+4 in the system which leads to a high solution supersaturation and consequently to a rapid formation rate of crystal (germination). The reverse phenomenon is observed at low phase ratio and (NH4)2CO3 concentration, where germination and crystal growth are slow and the product is mainly monocrystal. In the intermediate range, a mixture of polycrystal and aggregates is obtained. Residence and temperature are also shown to have an effect on the processes (the effect of time being more important than temperature). In the course of this study a bench-scale stripper-crystallizer was developped and operated successfully. (author). tables, graphs

  17. Extraction Factor Of Pure Ammonium Paratungstate From Tungsten Scraps

    Directory of Open Access Journals (Sweden)

    Pee J.-H.

    2015-06-01

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

  18. Structural basis for Mep2 ammonium transceptor activation by phosphorylation.

    Science.gov (United States)

    van den Berg, Bert; Chembath, Anupama; Jefferies, Damien; Basle, Arnaud; Khalid, Syma; Rutherford, Julian C

    2016-04-18

    Mep2 proteins are fungal transceptors that play an important role as ammonium sensors in fungal development. Mep2 activity is tightly regulated by phosphorylation, but how this is achieved at the molecular level is not clear. Here we report X-ray crystal structures of the Mep2 orthologues from Saccharomyces cerevisiae and Candida albicans and show that under nitrogen-sufficient conditions the transporters are not phosphorylated and present in closed, inactive conformations. Relative to the open bacterial ammonium transporters, non-phosphorylated Mep2 exhibits shifts in cytoplasmic loops and the C-terminal region (CTR) to occlude the cytoplasmic exit of the channel and to interact with His2 of the twin-His motif. The phosphorylation site in the CTR is solvent accessible and located in a negatively charged pocket ∼30 Å away from the channel exit. The crystal structure of phosphorylation-mimicking Mep2 variants from C. albicans show large conformational changes in a conserved and functionally important region of the CTR. The results allow us to propose a model for regulation of eukaryotic ammonium transport by phosphorylation.

  19. Increasing wheat production while decreasing nitrogen losses from ammonium bicarbonate

    International Nuclear Information System (INIS)

    The objectives of a 4-year field experiment were i) to investigate the effects of rate and timing of application of ammonium bicarbonate on N-uptake efficiency by irrigated winter wheat, ii) to determine the fate of fertilizer N in wheat followed by maize, and iii) to study nitrate dynamics in the soil after N-fertilizer application to evaluate groundwater pollution by leaching. Nitrogen-application rates significantly affected wheat grain yields and straw dry matter. Grain yields were higher with 150 than with 225 kg N ha-1, whereas the highest fractional recoveries of N from ammonium bicarbonate occurred with 75 kg N ha-1 (38.5% in 1994-95 and 33.5% in 1996-97). On the basis of grain yield, N recovery and soil-N balance, ammonium bicarbonate at 150 kg N ha-1, was the optimum rate, when applied basally and as a top dressing to wheat. Subsequent yields of maize stover and grain were affected by N applied to the wheat, suggesting that fertilizer recommendations, in terms of rate and timing, should be made on the basis of effects on the cropping rotation as a whole. Water-holding capacity of the soil was poor, therefore large applications of N are likely to cause nitrate pollution of ground water. (author)

  20. 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.

  1. Magnesium compounds

    Science.gov (United States)

    Kramer, D.A.

    2006-01-01

    In 2005, seawater and natural brines accounted for 51% of US magnesium compounds production. World magnesia production was estimated to be 14.5 Mt. Most of the production came from China, North Korea, Russia and Turkey. Although no specific production figures are available, Japan and the United States are estimated to account for almost one-half of the world's capacity from seawater and brines.

  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. Assessing the ammonium nitrate formation regime in the Paris megacity and its representation in the CHIMERE model

    Directory of Open Access Journals (Sweden)

    H. Petetin

    2015-09-01

    Full Text Available Secondary inorganic compounds represent a major fraction of fine aerosol in the Paris megacity. The thermodynamics behind their formation is now relatively well constrained, but due to sparse direct measurements of their precursors (in particular NH3 and HNO3, uncertainties remain on their concentrations and variability as well as the formation regime of ammonium nitrate (in terms of limited species, among NH3 and HNO3 in urban environments such as Paris. This study presents the first urban background measurements of both inorganic aerosol compounds and their gaseous precursors during several months within the city of Paris. Intense agriculture-related NH3 episodes are observed in spring/summer while HNO3 concentrations remain relatively low, even during summer, which leads to a NH3-rich regime in Paris. The local formation of ammonium nitrate within the city appears low, despite high NOx emissions. The dataset is also used to evaluate the CHIMERE chemistry-transport model (CTM. Interestingly, the rather good results obtained on ammonium nitrates hide significant errors on gaseous precursors (e.g. mean bias of −75 and +195 % for NH3 and HNO3, respectively. It thus leads to a mis-representation of the nitrate formation regime through a highly underestimated Gas Ratio metric (introduced by Ansari and Pandis, 1998 and a much higher sensitivity of nitrate concentrations to ammonia changes. Several uncertainty sources are investigated, pointing out the importance of better assessing both NH3 emissions and OH concentrations in the future. These results finally remind the caution required in the use of CTMs for emission scenario analysis, highlighting the importance of prior diagnostic and dynamic evaluations.

  4. Assessing the ammonium nitrate formation regime in the Paris megacity and its representation in the CHIMERE model

    Science.gov (United States)

    Petetin, Hervé; Sciare, Jean; Bressi, Michael; Gros, Valérie; Rosso, Amandine; Sanchez, Olivier; Sarda-Estève, Roland; Petit, Jean-Eudes; Beekmann, Matthias

    2016-08-01

    Secondary inorganic compounds represent a major fraction of fine aerosol in the Paris megacity. The thermodynamics behind their formation is now relatively well constrained but, due to sparse direct measurements of their precursors (in particular NH3 and HNO3), uncertainties remain on their concentrations and variability as well as the formation regime of ammonium nitrate (in terms of limited species among NH3 and HNO3) in urban environments such as Paris. This study presents the first urban background measurements of both inorganic aerosol compounds and their gaseous precursors during several months within the city of Paris. Intense agriculture-related NH3 episodes are observed in spring/summer while HNO3 concentrations remain relatively low, even during summer, which leads to a NH3-rich regime in Paris. The local formation of ammonium nitrate within the city appears low, despite high NOx emissions. The data set also allows evaluating the CHIMERE chemistry-transport model (CTM). Interestingly, the rather good results obtained on ammonium nitrates hide significant errors on gaseous precursors (e.g., mean bias of -75 and +195 % for NH3 and HNO3, respectively). This leads to a misrepresentation of the nitrate formation regime through a highly underestimated gas ratio metric (introduced by Ansari and Pandis, 1998) and a much higher sensitivity of nitrate concentrations to ammonia changes. Several uncertainty sources are investigated, pointing out the importance of better assessing both NH3 agricultural emissions and OH concentrations in the future. These results remind us of the caution required when using of CTMs for emission scenario analysis, highlighting the importance of prior diagnostic and dynamic evaluations.

  5. An Oxidative Desulfurization Catalyst Based on Bimodal Mesoporous Silica Containing Quaternary Ammonium Heteropolyphosphamolybdenum

    Institute of Scientific and Technical Information of China (English)

    Li Jian; Wu Haishun; Yang Lina; Ma Bo

    2016-01-01

    A bimodal mesoporous silica (BMMS) modiifed with amphiphilic compound (C19H42N)3(PMo12O40) (CTA-PMO) was prepared by the two-step impregnation method. Firstly, H3PMo12O40 was introduced into the bimodal mesoporous silica via impregnation, then C19H42NBr (CTAB) was grafted on the surface of BMMS containing H3PMo12O40 based on the chemical reaction between quaternary ammonium compound and the phosphomolybdic acid, and then the catalyst CTA-PMO/BMMS was obtained. The samples were characterized by XRD, N2 adsorption and desorption, FTIR,31P-NMR, 29Si-NMR and TEM analyses. It is shown that the catalyst has a typical bimodal mesoporous structure, in which the small mesopore diameter is about 3.0 nm and the large mesopore diameter is about 5.0 nm. The chemical interaction happens between the Keggin structure and silica group of BMMS. Compared with the mono-modal porous Hβ and SBA-15 zeolites modiifed with CTA-PMO, CTA-PMO/BMMS showed better catalytic activity in the oxidative conversion of dibenzothiophene (DBT), and the desulfurization rate can reach about 94% with the help of extraction, and the catalyst can be separated by ifltration and reused directly. The catalytic oxidative desulfurization mechanism on CTA-PMO/BMMS was proposed and veriifed.

  6. Revealing Brown Carbon Chromophores Produced in Reactions of Methylglyoxal with Ammonium Sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Peng; Laskin, Julia; Nizkorodov, Sergey A.; Laskin, Alexander

    2015-12-15

    Atmospheric brown carbon (BrC) is an important contributor to light absorption and climate forcing by aerosols. Reactions between small water-soluble carbonyls and ammonia or amines have been identified as one of the potential pathways of BrC formation. However, detailed chemical characterization of BrC chromophores has been challenging and their formation mechanisms are still poorly understood. Understanding BrC formation is impeded by the lack of suitable methods which can unravel the variability and complexity of BrC mixtures. This study applies high performance liquid chromatography (HPLC) coupled to photodiode array (PDA) detector and high resolution mass spectrometry (HRMS) to investigate optical properties and chemical composition of individual BrC components produced through reactions of methylglyoxal (MG) and ammonium sulfate (AS), both of which are abundant in the atmospheric environment. A direct relationship between optical properties and chemical composition of 30 major BrC chromophores was established. Nearly all of these chromophores are nitrogen-containing compounds that account for >70% of the overall light absorption by the MG+AS system in the 300-500 nm range. These results suggest that reduced-nitrogen organic compounds formed in reactions between atmospheric carbonyls and ammonia/amines are important BrC chromophores. It is also demonstrated that improved separation of BrC chromophores by HPLC will significantly advance understanding of BrC chemistry.

  7. Phase equilibria and modeling of ammonium ionic liquid, C2NTf2, solutions.

    Science.gov (United States)

    Domańska, Urszula; Marciniak, Andrzej; Królikowski, Marek

    2008-01-31

    Novel quaternary ammonium ionic liquid, ethyl(2-hydroxyethyl)dimethylammonium bis(trifluomethylsulfonyl)imide (C2NTf2), has been prepared from N,N-dimethylethanolamine as a substrate. The paper includes a specific basic characterization of the synthesized compound by NMR and the basic thermophysical properties: the melting point, enthalpy of fusion, enthalpy of solid-solid phase transition, glass transition determined by the differential scanning calorimetry (DSC), temperature of decomposition, and water content. The density of the new compound was measured. The solid-liquid or liquid-liquid phase equilibria of binary mixtures containing {C2NTf2+water or an alcohol (propan-1-ol, butan-1-ol, hexan-1-ol, octan-1-ol, decan-1-ol), aromatic hydrocarbons (benzene, toluene), aliphatic hydrocarbons (n-hexane, n-octane), dimethylsulfoxide (DMSO), or tetrahydrofuran (THF)} have been measured by a dynamic method in a wide range of temperatures from 230 to 430 K. These data were correlated by means of the nonrandom two-liquid (NRTL) equation utilizing temperature-dependent parameters derived from the solid-liquid or liquid-liquid equilibrium. From the solubility results, the negative value of the partition coefficient of ionic liquid in binary system octan-1-ol/water (log P) at 298.15 K has been calculated. PMID:18179194

  8. Cationic nanoparticles with quaternary ammonium-functionalized PLGA–PEG-based copolymers for potent gene transfection

    International Nuclear Information System (INIS)

    The objective of the present work was to develop new cationic nanoparticles (cNPs) with amphiphilic cationic copolymers for the delivery of plasmid DNA (pDNA). Cationic copolymers were built on the synthesis of quaternary ammonium salt compounds from diethylenetriamine (DETA) to include the positively charged head group and amphiphilic multi-grafts. PLGA-phe-PEG-qDETA (PPD), phe-PEG-qDETA-PLGA (PDP), and PLGA-phe-PEG-qDETA-PLGA (PPDP) cationic copolymers were created by this moiety of DETA quaternary ammonium, heterobifunctional polyethylene glycol (COOH-PEG-NH2), phenylalanine (phe), and poly(lactic-co-glycolic acid) (PLGA). These new cNPs were prepared by the water miscible solvent displacement method. They exhibit good pDNA binding ability, as shown in a retardation assay that occurred at a particle size of ∼217 nm. The zeta potential was approximately +21 mV when the cNP concentration was 25 mg/ml. The new cNPs also have a better buffering capacity than PLGA NPs. However, the pDNA binding ability was demonstrated starting at a weight ratio of approximately 6.25 cNPs/pDNA. Gene transfection results showed that these cNPs had transfection effects similar to those of Lipofectamine 2000 in 293T cells. Furthermore, cNPs can also transfect human adipose-derived stem cells. The results indicate that the newly developed cNP is a promising candidate for a novel gene delivery vehicle

  9. Hygroscopic behavior of multicomponent organic aerosols and their internal mixtures with ammonium sulfate

    Directory of Open Access Journals (Sweden)

    B. Jing

    2015-08-01

    Full Text Available Water soluble organic compounds (WSOCs are important components of organics in the atmospheric fine particulate matter. Although WSOCs play an important role in the hygroscopicity of aerosols, water uptake behavior of internally mixed WSOC aerosols remains limited characterization. Here, the hygroscopic properties of single component such as levoglucosan, oxalic acid, malonic acid, succinic acid and phthalic acid and multicomponent WSOC aerosols mainly involving oxalic acid are investigated with the hygroscopicity tandem differential mobility analyzer (HTDMA. The coexisting hygroscopic species including levoglucosan, malonic acid and phthalic acid have strong influence on the hygroscopic growth and phase behavior of oxalic acid, even suppress its crystallization completely. The interactions between oxalic acid and levoglucosan are confirmed by infrared spectra. The discrepancies between measured growth factors and predictions from Extended Aerosol Inorganics Model (E-AIM with UNIFAC method and Zdanovskii–Stokes–Robinson (ZSR approach increase at medium and high relative humidity (RH assuming oxalic acid in a solid state. For the internal mixture of oxalic acid with levoglucosan or succinic acid, there is enhanced water uptake at high RH due to positive chemical interactions between solutes. Organic mixture has more complex effect on the hygroscopicity of ammonium sulfate than single species. Although hygroscopic species such as levoglucosan accounts for a small fraction in the multicomponent aerosols, they may still strongly influence the hygroscopic behavior of ammonium sulfate by changing phase state of oxalic acid which plays the role of "intermediate" species. Considering the abundance of oxalic acid in the atmospheric aerosols, its mixtures with hygroscopic species may significantly promote water uptake under high RH conditions and thus affect the cloud condensation nuclei (CCN activity, optical properties and chemical reactivity of

  10. Oxidative stress in spring barley and common radish exposed to quaternary ammonium salts with hexafluorophosphate anion.

    Science.gov (United States)

    Biczak, Robert; Telesiński, Arkadiusz; Pawłowska, Barbara

    2016-10-01

    Quaternary ammonium salts (QAS), including ionic liquids (ILs), constitute a huge group of substances, which due to their desirable physical and chemical properties still attracts great interest in many industrial sectors. An increased concentration of this compound in the environment may lead to the contamination of the natural environment and may pose a potential threat to all organisms, including terrestrial higher plants. The present study demonstrates the interaction of three QAS with PF6(-) anions - tetramethylammonium [TMA][PF6], tetrabutylammonium [TBA][PF6], and tetrahexylammonium [THA][PF6] hexafluorophosphates - and its impact on the physiological and biochemical changes in spring barley seedlings and common radish plants. A similar study was also carried out by introducing the inorganic salt - ammonium hexafluorophosphate [A][PF6] to the soil; the results showed the soil became highly toxic to both plants. All the salts used led to significant changes in the metabolism of both spring barley and common radish which can be evidenced, for example, by a decrease in the content of chlorophyll a (Chla), chlorophyll b (Chlb), and total chlorophyll (Chla + b), as well as carotenoids (Car). The decrease in assimilation pigments was linearly correlated with an increasing concentration of QAS in the soil. QAS and [A][PF6] led to the formation of oxidative stress in both experimental plants, as evidenced by an increase in malondialdehyde (MDA) content in their cells and the changes in H2O2 level. In response to stress, the plants synthesized enzymatic free radicals (ROS) scavengers that lead to changes in the activity of superoxide dismutase (SOD) and catalase (CAT), as well as significantly increased peroxidase (POD) activity. A decrease in the content of assimilation pigments and an increased POD activity are the most reliable indices of oxidative stress, and concurrently the signs of premature plants aging. Common radish proved to be more resistant to the

  11. Ammonium removal from high-strength aqueous solutions by Australian zeolite.

    Science.gov (United States)

    Wijesinghe, D Thushari N; Dassanayake, Kithsiri B; Sommer, Sven G; Jayasinghe, Guttila Y; J Scales, Peter; Chen, Deli

    2016-07-01

    Removal of ammonium nitrogen (NH4(+)-N) particularly from sources which are highly rich in nitrogen is important for addressing environmental pollution. Zeolites, aluminosilicate minerals, are commonly used as commercial adsorbents and ion-exchange medium in number of commercial applications due to its high adsorption capacity of ammonium (NH4(+)). However, detailed investigations on NH4(+) adsorption and ion exchange capacities of Australian natural zeolites are rare, particularly under higher NH4(+) concentrations in the medium. Therefore, this study was conducted to determine NH4(+) adsorption characteristics of Australian natural zeolites at high NH4(+) concentrations with and without other chemical compounds in an aqueous solution. Results showed that initial NH4(+) concentration, temperature, reaction time, and pH of the solution had significant effects on NH4(+) adsorption capacity of zeolite. Increased retention time and temperature generally had a positive impact on adsorption. Freundlich model fitted well with adsorption process of Australian natural zeolites; however, Langmuir model had best fitted for the adsorption process of sodium (Na(+)) treated zeolites. NaCl treatment increased the NH4(+) adsorption capacity of Australian zeolites by 25% at 1000 mg-N, NH4(+) solution. The maximum adsorption capacity of both natural Australian zeolites and Na(+) treated zeolites were estimated as 9.48 and 11.83 mg-N/g, respectively, which is lower than many zeolites from other sources. Compared to the NH4(+) only medium, presence of other competitive ions and acetic acid in the medium (resembling composition in digested swine manure slurries) reduced NH4(+) removal of natural and Na(+) treated zeolites by 44% and 57%, respectively. This suggests detailed investigations are required to determine practically achievable NH4(+) -N removal potential of zeolites for applications in complex mediums such as animal manure slurries. PMID:27050255

  12. Reassimilation of Photorespiratory Ammonium in Lotus japonicus Plants Deficient in Plastidic Glutamine Synthetase.

    Science.gov (United States)

    Pérez-Delgado, Carmen M; García-Calderón, Margarita; Márquez, Antonio J; Betti, Marco

    2015-01-01

    It is well established that the plastidic isoform of glutamine synthetase (GS2) is the enzyme in charge of photorespiratory ammonium reassimilation in plants. The metabolic events associated to photorespiratory NH4(+) accumulation were analyzed in a Lotus japonicus photorespiratory mutant lacking GS2. The mutant plants accumulated high levels of NH4(+) when photorespiration was active, followed by a sudden drop in the levels of this compound. In this paper it was examined the possible existence of enzymatic pathways alternative to GS2 that could account for this decline in the photorespiratory ammonium. Induction of genes encoding for cytosolic glutamine synthetase (GS1), glutamate dehydrogenase (GDH) and asparagine synthetase (ASN) was observed in the mutant in correspondence with the diminishment of NH4(+). Measurements of gene expression, polypeptide levels, enzyme activity and metabolite levels were carried out in leaf samples from WT and mutant plants after different periods of time under active photorespiratory conditions. In the case of asparagine synthetase it was not possible to determine enzyme activity and polypeptide content; however, an increased asparagine content in parallel with the induction of ASN gene expression was detected in the mutant plants. This increase in asparagine levels took place concomitantly with an increase in glutamine due to the induction of cytosolic GS1 in the mutant, thus revealing a major role of cytosolic GS1 in the reassimilation and detoxification of photorespiratory NH4(+) when the plastidic GS2 isoform is lacking. Moreover, a diminishment in glutamate levels was observed, that may be explained by the induction of NAD(H)-dependent GDH activity.

  13. Ammonium removal from high-strength aqueous solutions by Australian zeolite.

    Science.gov (United States)

    Wijesinghe, D Thushari N; Dassanayake, Kithsiri B; Sommer, Sven G; Jayasinghe, Guttila Y; J Scales, Peter; Chen, Deli

    2016-07-01

    Removal of ammonium nitrogen (NH4(+)-N) particularly from sources which are highly rich in nitrogen is important for addressing environmental pollution. Zeolites, aluminosilicate minerals, are commonly used as commercial adsorbents and ion-exchange medium in number of commercial applications due to its high adsorption capacity of ammonium (NH4(+)). However, detailed investigations on NH4(+) adsorption and ion exchange capacities of Australian natural zeolites are rare, particularly under higher NH4(+) concentrations in the medium. Therefore, this study was conducted to determine NH4(+) adsorption characteristics of Australian natural zeolites at high NH4(+) concentrations with and without other chemical compounds in an aqueous solution. Results showed that initial NH4(+) concentration, temperature, reaction time, and pH of the solution had significant effects on NH4(+) adsorption capacity of zeolite. Increased retention time and temperature generally had a positive impact on adsorption. Freundlich model fitted well with adsorption process of Australian natural zeolites; however, Langmuir model had best fitted for the adsorption process of sodium (Na(+)) treated zeolites. NaCl treatment increased the NH4(+) adsorption capacity of Australian zeolites by 25% at 1000 mg-N, NH4(+) solution. The maximum adsorption capacity of both natural Australian zeolites and Na(+) treated zeolites were estimated as 9.48 and 11.83 mg-N/g, respectively, which is lower than many zeolites from other sources. Compared to the NH4(+) only medium, presence of other competitive ions and acetic acid in the medium (resembling composition in digested swine manure slurries) reduced NH4(+) removal of natural and Na(+) treated zeolites by 44% and 57%, respectively. This suggests detailed investigations are required to determine practically achievable NH4(+) -N removal potential of zeolites for applications in complex mediums such as animal manure slurries.

  14. Hygroscopic behavior of multicomponent organic aerosols and their internal mixtures with ammonium sulfate

    Science.gov (United States)

    Jing, Bo; Tong, Shengrui; Liu, Qifan; Li, Kun; Wang, Weigang; Zhang, Yunhong; Ge, Maofa

    2016-03-01

    Water-soluble organic compounds (WSOCs) are important components of organics in the atmospheric fine particulate matter. Although WSOCs play an important role in the hygroscopicity of aerosols, knowledge on the water uptake behavior of internally mixed WSOC aerosols remains limited. Here, the hygroscopic properties of single components such as levoglucosan, oxalic acid, malonic acid, succinic acid, phthalic acid, and multicomponent WSOC aerosols mainly involving oxalic acid are investigated with the hygroscopicity tandem differential mobility analyzer (HTDMA). The coexisting hygroscopic species including levoglucosan, malonic acid, and phthalic acid have a strong influence on the hygroscopic growth and phase behavior of oxalic acid, even suppressing its crystallization completely during the drying process. The phase behaviors of oxalic acid/levoglucosan mixed particles are confirmed by infrared spectra. The discrepancies between measured growth factors and predictions from Extended Aerosol Inorganics Model (E-AIM) with the Universal Quasi-Chemical Functional Group Activity Coefficient (UNIFAC) method and Zdanovskii-Stokes-Robinson (ZSR) approach increase at medium and high relative humidity (RH) assuming oxalic acid in a crystalline solid state. For the internal mixture of oxalic acid with levoglucosan or succinic acid, there is enhanced water uptake at high RH compared to the model predictions based on reasonable oxalic acid phase assumption. Organic mixture has more complex effects on the hygroscopicity of ammonium sulfate than single species. Although hygroscopic species such as levoglucosan account for a small fraction in the multicomponent aerosols, they may still strongly influence the hygroscopic behavior of ammonium sulfate by changing the phase state of oxalic acid which plays the role of "intermediate" species. Considering the abundance of oxalic acid in the atmospheric aerosols, its mixtures with hygroscopic species may significantly promote water uptake

  15. Cationic nanoparticles with quaternary ammonium-functionalized PLGA–PEG-based copolymers for potent gene transfection

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yan-Hsung [Kaohsiung Medical University, School of Dentistry, College of Dental Medicine (China); Fu, Yin-Chih [Kaohsiung Medical University, Graduate Institute of Medicine, College of Medicine (China); Chiu, Hui-Chi [Kaohsiung Medical University, Department of Medicinal and Applied Chemistry, College of Life Science (China); Wang, Chau-Zen [Kaohsiung Medical University, Department of Physiology, College of Medicine (China); Lo, Shao-Ping [Kaohsiung Medical University, Department of Medicinal and Applied Chemistry, College of Life Science (China); Ho, Mei-Ling [Kaohsiung Medical University, Department of Physiology, College of Medicine (China); Liu, Po-Len [Kaohsiung Medical University, Department of Respiratory Therapy, College of Medicine (China); Wang, Chih-Kuang, E-mail: ckwang@kmu.edu.tw [Kaohsiung Medical University, Department of Medicinal and Applied Chemistry, College of Life Science (China)

    2013-11-15

    The objective of the present work was to develop new cationic nanoparticles (cNPs) with amphiphilic cationic copolymers for the delivery of plasmid DNA (pDNA). Cationic copolymers were built on the synthesis of quaternary ammonium salt compounds from diethylenetriamine (DETA) to include the positively charged head group and amphiphilic multi-grafts. PLGA-phe-PEG-qDETA (PPD), phe-PEG-qDETA-PLGA (PDP), and PLGA-phe-PEG-qDETA-PLGA (PPDP) cationic copolymers were created by this moiety of DETA quaternary ammonium, heterobifunctional polyethylene glycol (COOH-PEG-NH{sub 2}), phenylalanine (phe), and poly(lactic-co-glycolic acid) (PLGA). These new cNPs were prepared by the water miscible solvent displacement method. They exhibit good pDNA binding ability, as shown in a retardation assay that occurred at a particle size of ∼217 nm. The zeta potential was approximately +21 mV when the cNP concentration was 25 mg/ml. The new cNPs also have a better buffering capacity than PLGA NPs. However, the pDNA binding ability was demonstrated starting at a weight ratio of approximately 6.25 cNPs/pDNA. Gene transfection results showed that these cNPs had transfection effects similar to those of Lipofectamine 2000 in 293T cells. Furthermore, cNPs can also transfect human adipose-derived stem cells. The results indicate that the newly developed cNP is a promising candidate for a novel gene delivery vehicle.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-04-01

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

  17. Regeneration of clinoptilolite zeolite used for the ammonium removal

    International Nuclear Information System (INIS)

    The use of zeolites has been increased in the last years with different applications and with a great boom in the environmental area, but a little had been make about the regeneration of such zeolites. The presence of nitrogen-ammonia in water may cause serious pollution problems since it results to be toxic for fishes and other aquatic life forms, also it provokes the algae growing. The natural clinoptilolite contains interchangeable ions such as the sodium (Na+), potassium (K+), magnesium (Mg2+) and calcium (Ca2+) in different proportions depending on the mineral origin When the zeolite is upgraded to its sodium form, the cation exchange capacity and the preference by the nitrogen-ammonia are increased, allowing the reversible process of sorption. In this work it was proposed the regeneration to its sodium form about the ammonia clinoptilolite zeolite. The natural mineral was characterized using the methods such as: X-ray diffraction, Infrared spectroscopy, Thermal gravimetric analysis and surface area. The results show that the ammonium sorption was between 95% and 98.7% such an ambient temperature as a flow back. the zeolite was regenerated approximately from 60% in the first cycle up to 97% in the last cycle at flow back temperature and of 59.2% up to 96.9% at ambient temperature, it was not presented any significant effect which could be attributed to the temperature. During the exchange process, the cations present in the natural zeolite were exchanged with the ammonium ions, this process was not completed due to that retained ammonium quantity was major that of the desorpted ions, what shows that in addition of ion exchange, another type of sorption process exists. (Author)

  18. 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.

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

    Science.gov (United States)

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

    2010-04-01

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

  20. Ammonium diamminesilver(I bis(5-chloro-2-hydroxybenzenesulfonate trihydrate

    Directory of Open Access Journals (Sweden)

    Zhao-Peng Deng

    2012-02-01

    Full Text Available The reaction of silver nitrate with 5-chloro-2-hydroxybenzenesulfonic acid in the presence of ammonia yielded the title salt, (NH4[Ag(NH32](C6H4ClO4S2·3H2O. The AgI ion shows linear coordination [N—Ag—N = 175.2 (1 °]. The ammonium and diamminesilver cations, the benzenesulfonate anion and the lattice water molecules interact through an intricate network of N—H...O and O—H...O hydrogen bonds to form a three-dimensional network.

  1. Experimental study of the detonation of technical grade ammonium nitrate

    Science.gov (United States)

    Presles, Henri-Noël; Vidal, Pierre; Khasainov, Boris

    2009-11-01

    The detonation of technical grade ammonium nitrate at the density ρ=0.666 g/cm confined in PVC and steel tubes was experimentally studied. The results show that the detonation is self-sustained and steady in steel tubes with diameter as small as 12 mm. Critical detonation diameter lies between 8 and 12 mm in 2 mm thick steel tubes and between 55 and 81 mm in PVC tubes. These values testify a strong detonation sensitivity of this product. To cite this article: H.-N. Presles et al., C. R. Mecanique 337 (2009).

  2. Aluminum-silicates flotation with quaternary ammonium salts

    Institute of Scientific and Technical Information of China (English)

    王毓华; 胡岳华; 陈湘清

    2003-01-01

    The zeta potential measurements show that the flotation separation of diaspore from kaolinite, illite and pyrophyllite could be achieved in the range of pH 46.5 with cationic collectors. A special quaternary ammonium salts(DTAL) shows better selectivity than that the dodecyl amine(DDA) does for the flotation of three silicates. The closed-circuit flotation results show that the reverse flotation de-silicate can be achieved with DTAL as collector, a new inorganic reagent(SFL) as depressant and MIBC as frother to obtain a bauxite concentrate m(Al2O3)/m(SiO2)>10, Al2O3 recovery>86%).

  3. Prediction of Particle Size of Ammonium Perchlorate during Pulverisation

    Directory of Open Access Journals (Sweden)

    Sunil Jain

    2006-07-01

    Full Text Available Ammonium perchlorate has been pulverised by an impact mill (air classifier mill to studythe influence of different operating parameters, viz., effect of mill speed, classifier speed, feedrate, and damper opening (suction rate on the particle size. Further based on the differentgrinding parameters, an empirical equation has been developed and used for the prediction ofparticle size. The experimental results indicate that the values are very close to the predictedones. In addition, particle size distribution has also been studied by applying different modelequations and it has been found that Rosin-Rammler model is the most suitable model for thisoperation.

  4. Ammonium sulphate on maize crops under no tillage

    OpenAIRE

    Maria Anita Gonçalves da Silva; Anny Rosi Mannigel; Antonio Saraiva Muniz; Simone Maria Altoé Porto; Marlene Estevão Marchetti; Antonio Nolla; Rosemary Marques de Almeida Bertani

    2012-01-01

    The objectives of this work were to evaluate the management of N and S (as ammonium sulphate) fertilization under no-tillage system on the components of maize productivity and on N and S accumulation in the crop, as well as to evaluate the minimum value of the Nitrogen Sufficiency Index (NSI 0.95) as an indicator for side dressing requirements. The experiment had a completely randomized block design with six treatments and four replications carried out in Red Latosol dystrophic soil (Hapludox...

  5. Further laboratory and theoretical investigations of ammonium dinitramide

    Energy Technology Data Exchange (ETDEWEB)

    Tulis, A.J.; Snelson, A. [IIT Research Institut, Chicago (United States); Heberlein, C.; Patel, D.L. [U.S. Army Cecom RD et E Center, NVESD (United States)

    1996-12-31

    Hydrogen and deuterated ammonium dinitramide have been vaporized under high vacuum and the IR matrix isolation spectra of the decomposition products obtained. Tentative vibration assignments have been made for HN(NO{sub 2}){sub 2} and DN(NO{sub 2}){sub 2} assuming a symmetrical non-planar structure in which the H or D is bonded to the central nitrogen atom. Other structures are also possible. Ab initio calculations have been made for the various structural isomers of hydrogen dinitramide. Vibration frequencies calculated for the hydrogenated and deuterated species are compared with the experimental values with the object of identifying the molecules` structure. (authors) 3 refs.

  6. Surface energy and crystallization phenomena of ammonium dinitramide

    Energy Technology Data Exchange (ETDEWEB)

    Teipel, Ulrich; Heintz, Thomas [Fraunhofer-Institut fuer Chemische Technologie (ICT), PO Box 1240, D-76318 Pfinztal (Germany)

    2005-12-01

    Ammonium dinitramide (ADN) was characterized during recrystallization from the melt. The surface tension of molten ADN at 97 C was measured to be 89 mN/m. The wetting angles between molten ADN and different solid surfaces (polytetrafluoroethylene, glass, steel, and aluminum) were determined. The wettability depends on the surface tension of molten ADN, the free surface energy of the solid surfaces and the interfacial tension between the solid and liquid. Observations of the recrystallization behavior of molten ADN showed that nucleation does not occur, even at super cooling rates of 70 K. Crystallization can be initiated by the application of seed crystals. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  7. The effect of the ammonium ion on activated-sludge settling properties

    DEFF Research Database (Denmark)

    Novak, John Thomas

    2001-01-01

    High levels of sodium in wastewater have been found to be detrimental to activated-sludge. settling and dewatering. Another potentially troublesome monovalent cation in activated-sludge systems is the ammonium ion. This study was conducted to determine if the ammonium ion could alter activated...... that the ammonium concentration would increase or by adding sodium. These studies showed that an increase in either sodium or ammonium would cause activated-sludge settling properties to deteriorate. When the monovalent-to-divalent cation ratio on a charge-equivalent basis was increased from 2.4 to 4.7 either...... by addition of sodium or ammonium, the interfacial settling velocity decreased, although the greatest drop was in the reactor containing ammonium. When addition of the nitrification inhibitor was stopped, rapid recovery of nitrification occurred but the settling properties improved more slowly. It seemed...

  8. Ober Phaseniibergange von Ammonium-Alkali-Jodiden und verwandten Halogeniden / Phase Transitions of Ammonium-alkali Iodides and Related Halides

    Science.gov (United States)

    Brauer, Peter

    1981-03-01

    The investigation of the order-disorder transitions of the ammonium-chlorides and -bromides, in which some of the NH4+ are replaced by Cs+, Rb+ or K+, is extended to the corresponding iodides using birefringence and differential thermal analysis. As the temperature range of the martensitic transition (Pm 3 m↔Fm 3 m) is now overlapping the temperature range of the orderdisorder transitions, the former must be included in the measurements. The results allowing an overlook are discussed using the work of Garland, Lushington, and Leung [5

  9. Shock Initiation and Equation of State of Ammonium Nitrate

    Science.gov (United States)

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

    2013-06-01

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

  10. Ammonium nitrate as an oxidizer in solid composite propellants

    Science.gov (United States)

    Manelis, G. B.; Lempert, D. B.

    2009-09-01

    Despite the fact that ammonium nitrate (AN) has the highest hydrogen content and fairly high oxygen balance (compared to other oxidizers), its extremely low formation enthalpy and relatively low density makes it one of the worst power oxidizers in solid composite propellants (SCP). Nevertheless, AN has certain advantages - the combustion of the compositions containing AN is virtually safe, its combustion products are ecologically clean, it is very accessible and cheap, and also very thermostable (far more stable than ammonium dinitramide (ADN)). Besides, its low density stops being a disadvantage if the propellant has to be used in deep space and therefore, must be carried there with other rocket carriers. The low cost of AN may also become a serious advantage in the AN application even in lower stages of multistage space launchers as well as in one-stage space launchers with low mass fraction of the propellant. The main specific features relevant to the creation of AN-based SCPs with the optimal energetic characteristics are discussed. The use of metals and their hydrides and proper fuel-binders as well as the recent successes in phase stabilization of AN are described.

  11. Effects of Calcium Lignosulfonate and Silicic Acid on Ammonium Nitrate Degradation

    Directory of Open Access Journals (Sweden)

    Ahmet Ozan Gezerman

    2014-01-01

    Full Text Available Ammonium nitrate salts are the most commonly used nitrogenous fertilizers in industry. However, storage of ammonium nitrate is problematic, since its initial properties can decline because of environmental factors, leading to large economic losses. In this study, in order to prevent the caking and degradation of ammonium nitrate, an alternative composition with additional calcium lignosulfonate and silicic acid was studied. The resulting fertilizer was analyzed by screening analysis, ion chromatography, and electron microscopy methods.

  12. Influence of different ammonium, lactate and glutamine concentrations on CCO cell growth

    OpenAIRE

    Slivac, Igor; Blajić, Višnja; Radošević, Kristina; Kniewald, Zlatko; Gaurina Srček, Višnja

    2010-01-01

    In this study the effects of ammonium and lactate on a culture of channel catfish ovary (CCO) cells were examined. We also made investigation on the influence of glutamine, since our previous research revealed that this amino acid stimulated CCO cell growth more than glucose in a concentration-dependent manner. The effect of ammonium in cell culture included the considerable decrease in cell growth rate with eventual growth arrest as well as the retardation of glucose consumption. At ammonium...

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

    OpenAIRE

    Malovanyy, Andriy

    2014-01-01

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

  14. Influence of Ammonium Salts and Cane Molasses on Growth of Alcaligenes eutrophus and Production of Polyhydroxybutyrate

    OpenAIRE

    Beaulieu, M.; Beaulieu, Y.; Melinard, J.; Pandian, S.; GOULET, J.

    1995-01-01

    The production of polyhydroxybutyrate (PHB) by Alcaligenes eutrophus DSM 545 was studied in a synthetic medium with 3% glucose at pH 7.0 supplemented with several ammonium substrates and cane molasses. Growth was measured by dry cell weight, and the PHB content was measured by gas chromatography. The effects of ammonium sources such as sulfate, nitrate, phosphate, and chloride salts and those of different ammonium sulfate concentrations were evaluated. The best growth and PHB production were ...

  15. Technology Development and Production of Certain Chemical Platinum Metals Compounds at JSC "Krastsvetmet"

    Institute of Scientific and Technical Information of China (English)

    ILYASHEVICH V.D.; PAVLOVA E.I.; KORITSKAYA N.G.; MAMONOV S.N.; SHULGIN D.R.; MALTSEV E.V.

    2012-01-01

    In recent years JSC "Krastsvetmet" has successfully developed the production of chemically pure compounds of precious metals.Currently methods have been developed and facilities have been provided for industrial production of the following platinum metals compounds:- Rhodium (Ⅲ) chloride hydrate,rhodium (Ⅲ) chloride solution,rhodium ( Ⅲ) nitrate solution,rhodium ( Ⅲ)iodide,rhodium ( Ⅲ) sulfate,hydrated rhodium ( Ⅲ) oxide,ammonium hexachlororodiate,rhodium ( Ⅲ)phosphate solution,rhodium electrolytes;Iridium (Ⅳ) chloride hydrate,iridium (Ⅲ) chloride hydrate,ammonium hexachloroiridate (Ⅳ),hexachloriridium acid solution,hexachloriridium crystalline acid;- Ruthenium (Ⅲ) chloride hydrate,ruthenium (Ⅳ) hydroxide chloride,ruthenium (Ⅳ) hydroxide chloride solution,ammonium hexachlororuthenate,ruthenium (Ⅲ) chloride solution,potassium,diaquaoctachloronitrido diruthenate.The quality of the production meets the requirements of Russian and foreign consumers.

  16. Seasonal changes in nitrogen availability, and root and microbial uptake of 15N13C9-phenylalanine and 15N-ammonium in situ at a temperate heath

    DEFF Research Database (Denmark)

    Andresen, Louise C.; Michelsen, Anders; Jonasson, Sven Evert;

    2011-01-01

    In the plant biosynthesis of secondary compounds, phenylalanine is a precursor of condensed tannins. Tannins are deposited into the soil in plant root exudates and dead plant material and have been suggested to precipitate some soil nutrients and hence reduce nutrient availability for plants. Free...... amino acid,inorganic and microbial N concentration during the growing season was investigated in an ecosystem with a natural tannin chemosphere. The influence of tannins on the uptake of nitrogen in plants and microbes was followed by injecting tannic acid (TA), ammonium-15N and phenylalanine-15N/13C9....... Plants preferred ammonium over phenylalanine, while microbes had no preference. Soil microbes had a 77% uptake of intact phenylalanine. Phenylalanine was acquired intact by both grasses and Calluna, with 63% and 38% uptake of intact phenylalanine in grass fine roots and Calluna roots, respectively...

  17. Crystal structure of tetra­ethyl­ammonium chloride 3,4,5,6-tetra­fluoro-1,2-di­iodo­benzene

    OpenAIRE

    Viger-Gravel, Jasmine; Korobkov, Ilia; Bryce, David L.

    2015-01-01

    Equimolar qu­anti­ties of tetra­ethyl­ammonium chloride (Et4NCl) and 3,4,5,6-tetra­fluoro-1,2-di­iodo­benzene (o-DITFB or o-C6F4I2) have been co-crystallized in a solution of di­chloro­methane yielding a pure halogen-bonded compound, 3,4,5,6-tetra­fluoro-1,2-di­iodo­benzene–tetra­ethyl ammonium chloride (2/1), Et4N+·Cl−·2C6F4I2, in the form of translucent needles. [(Et4NCl)(o-C6F4I2)2] packs in the C2/c space group. The asymmetric unit includes one mol­ecule of DITFB, one Et4N+ cation located...

  18. Studies on Biquaternary Ammonium Salt Algaecide for Removing Red Tide Algae

    Institute of Scientific and Technical Information of China (English)

    刘洁生; 张珩; 杨维东; 高洁; 柯琼

    2004-01-01

    The paper deals with the removal and control of red tide algae, Phaeoecystis globosa and Alexandrium tamarense by biquaternary ammonium salt algaecide. The results show that the efficient concentration of biquaternary ammonium salt to control the two algaes in 96 h is 0.8 mg · L-1 and 0.4 mg · L-1, respectively. It is found that biquaternary ammonium salt has high efficiency and longer duration of action in the removal and control of algae.Biquaternary ammonium salt might be an excellent algaecide to control HAB.

  19. Highly efficient hydrogen storage system based on ammonium bicarbonate/formate redox equilibrium over palladium nanocatalysts.

    Science.gov (United States)

    Su, Ji; Yang, Lisha; Lu, Mi; Lin, Hongfei

    2015-03-01

    A highly efficient, reversible hydrogen storage-evolution process has been developed based on the ammonium bicarbonate/formate redox equilibrium over the same carbon-supported palladium nanocatalyst. This heterogeneously catalyzed hydrogen storage system is comparable to the counterpart homogeneous systems and has shown fast reaction kinetics of both the hydrogenation of ammonium bicarbonate and the dehydrogenation of ammonium formate under mild operating conditions. By adjusting temperature and pressure, the extent of hydrogen storage and evolution can be well controlled in the same catalytic system. Moreover, the hydrogen storage system based on aqueous-phase ammonium formate is advantageous owing to its high volumetric energy density.

  20. Ammonium sulphate on maize crops under no tillage

    Directory of Open Access Journals (Sweden)

    Maria Anita Gonçalves da Silva

    2012-01-01

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

  1. Accelerated OH(-) transport in activated carbon air cathode by modification of quaternary ammonium for microbial fuel cells.

    Science.gov (United States)

    Wang, Xin; Feng, Cuijuan; Ding, Ning; Zhang, Qingrui; Li, Nan; Li, Xiaojing; Zhang, Yueyong; Zhou, Qixing

    2014-04-01

    Activated carbon (AC) is a promising catalyst for the air cathode of microbial fuel cells (MFCs) because of its high performance and low cost. To increase the performance of AC air cathodes, the acceleration of OH(-) transport is one of the most important methods, but it has not been widely investigated. Here we added quaternary ammonium to ACs by in situ anchoring of a quaternary ammonium/epoxide-reacting compound (QAE) or ex situ mixing with anion exchange resins in order to modify ACs from not only the external surface but also inside the pores. In 50 mM phosphate buffer solution (PBS), the in situ anchoring of QAE was a more effective way to increase the power. The highest power density of 2781 ± 36 mW/m(2), which is 10% higher than that of the control, was obtained using QAE-anchored AC cathodes. When the medium was switched to an unbuffered NaCl solution, the increase in maximum power density (885 ± 25 mW/m(2)) was in accordance with the anion exchange capacity (0.219 mmol/g). The highest power density of the anion exchange resin-mixed air cathode was 51% higher than that of the control, indicating that anion exchange is urgently needed in real wastewaters. Excess anchoring of QAE blocked both the mesopores and micropores, causing the power output to be inhibited. PMID:24597673

  2. Physicochemical properties of ammonium-based deep eutectic solvents and their electrochemical evaluation using organometallic reference redox systems

    International Nuclear Information System (INIS)

    Highlights: • Physicochemical properties of seven deep eutectic solvents as electrolytes measured. • Walden plot showed ideal ammonium-based deep eutectic solvents. • Potential windows of all deep eutectic solvents determined. • Diffusion coefficients and rate constants of organometallic redox couples measured. • Rate constants of deep eutectic solvents were lower than those of ionic liquids. -- Abstract: Seven deep eutectic solvents (DESs) containing ammonium based salts are prepared by means of hydrogen bonding with acid, amine, amide and nitrate based compounds. The major physicochemical properties of the DESs in terms of density, viscosity, electrical conductivity, molar conductivity and pH are investigated prior to ascertaining their electrochemical characteristics by means of cyclic voltammetry and chronoamperometry. Nitrate based DESs exhibit higher conductivities but lower viscosities than other DESs, whereas the amide based DES displays the widest electrochemical potential window. Diffusion coefficient, D, of two organometallic redox couples, Fc/Fc+ (ferrocene/ferrocenium) and Cc/Cc+(cobaltocene/cobaltocenium) is found to be of the order of 10−9 to 10−8 cm2 s−1 in all studied DESs while the heterogeneous rate constant for electron transfer across the electrode/DES interface is of the order of 10−4 cm s−1. The Stokes–Einstein products of Fc and Cc+ in the DESs have also been determined

  3. ANTIMICROBIAL REAGENTS AS FUNCTIONAL FINISHING FOR TEXTILES INTENDED FOR BIOMEDICAL APPLICATIONS. I. SYNTHETIC ORGANIC COMPOUNDS

    Directory of Open Access Journals (Sweden)

    Madalina Zanoaga

    2014-06-01

    Full Text Available This article offers an overview of some contemporary antimicrobial (biocides and biostatics agents used as functional finishing for textiles intended for biomedical applications. It reviews only synthetic agents, namely quaternary ammonium compounds, halogenated phenols, polybiguanides, N-halamines, and renewable peroxides, as a part of an extensive study currently in progress.

  4. Single stage biological nitrogen removal by nitritation and anaerobic ammonium oxidation in biofilm systems.

    Science.gov (United States)

    Helmer, C; Tromm, C; Hippen, A; Rosenwinkel, K H; Seyfried, C F; Kunst, S

    2001-01-01

    In full scale wastewater treatment plants with at times considerable deficits in the nitrogen balances, it could hitherto not be sufficiently explained which reactions are the cause of the nitrogen losses and which micro-organisms participate in the process. The single stage conversion of ammonium into gaseous end-products--which is henceforth referred to as deammonification--occurs particularly frequently in biofilm systems. In the meantime, one has succeeded to establish the deammonification processes in a continuous flow moving-bed pilot plant. In batch tests with the biofilm covered carriers, it was possible for the first time to examine the nitrogen conversion at the intact biofilm. Depending on the dissolved oxygen (DO) concentration, two autotrophic nitrogen converting reactions in the biofilm could be proven: one nitritation process under aerobic conditions and one anaerobic ammonium oxidation. With the anaerobic ammonium oxidation, ammonium as electron donor was converted with nitrite as electron acceptor. The end-product of this reaction was N2. Ammonium and nitrite did react in a stoichiometrical ratio of 1:1.37, a ratio which has in the very same dimension been described for the ANAMMOX-process (1:1.31 +/- 0.06). Via the oxygen concentration in the surrounding medium, it was possible to control the ratio of nitritation and anaerobic ammonium oxidation in the nitrogen conversion of the biofilm. Both processes were evenly balanced at a DO concentration of 0.7 mg/l, so that it was possible to achieve a direct, almost complete elimination of ammonium without addition of nitrite. One part of the provided ammonium did participate in the nitritation, the other in the anaerobic ammonium oxidation. Through the aerobic ammonium oxidation into nitrite within the outer oxygen supplied layers of the biofilm, the reaction partner was produced for the anaerobic ammonium oxidation within the inner layers of the biofilm. PMID:11379106

  5. Laser-induced breakdown spectroscopy (LIBS) for detection of ammonium nitrate in soils

    Science.gov (United States)

    Díaz, Daniel; Hahn, David W.; Molina, Alejandro

    2009-05-01

    The extensive use of improvised explosive devices (IED) by irregular armed groups in Colombia has posed a threat, not only to the Colombian regular army but to the civilian population. It is expected that in future years, after an eventual cease fire, humanitarian missions for IED clearance will be fundamental to secure safe transit of people and goods, particularly in Colombian rural areas. The clandestine nature of IEDs preparation in Colombia yielded a rather diverse nature of these irregular weapons. Although, some have metal parts such as nails and shrapnel, others are metal-free devices in which detonation is obtained by chemical means. Despite this variability in IEDs design, one thing that is common in IEDs preparation is the use of significant amounts of ANFO (ammonium nitrate (AN), fuel oil (FO)) in their construction. The goal of this work was to identify AN and FO in soils using LIBS. Experiments showed the ability of LIBS to identify the presence of AN based on Hα (656.3 nm) and Hβ (486.1 nm) emission lines. It was not possible to identify FO mixed with soils in the spectral windows studied. FO caused a reduction on spark intensity on the samples. This would represent a challenge for identification of chemical compounds in wet soils. Potential interferences with fertilizers are discussed as well.

  6. A simple spectrophotometric method for the determination of captopril in pharmaceutical preparations using ammonium molybdate

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, P.R.S., E-mail: pauloufma@ufma.b [Universidade Federal do Maranhao (CCSST/UFMA), Imperatriz, MA (Brazil). Centro de Ciencias Sociais, Saude e Tecnologia; Pezza, L.; Pezza, H.R. [UNESP, Araraquara, SP (Brazil). Inst. de Quimica

    2010-09-15

    A simple, rapid and sensitive spectrophotometric method for the determination of captopril (CPT) in pharmaceutical formulations is proposed. This method is based on the reduction reaction of ammonium molybdate, in the presence of sulphuric acid, for the group thiol of CPT, producing a green compound ({lambda}{sub max} 407 nm). Beer's law is obeyed in a concentration range of 4.60 x 10{sup -4} - 1.84 x 10{sup -3} mol l{sup -1} of CPT with an excellent correlation coefficient (r = 0.9995). The limit of detection and limit of quantification were 7.31 x 10{sup -6} and 2.43 x 10{sup -5} mol l{sup -1} of CPT, respectively. The proposed method was successfully applied to the determination of CPT in commercial brands of pharmaceuticals. No interferences were observed from the common excipients in the formulations. The results obtained by the proposed method were favorably compared with those given by the official reported method at 95 % confidence level. (author)

  7. Quaternary ammonium silane-functionalized, methacrylate resin composition with antimicrobial activities and self-repair potential.

    Science.gov (United States)

    Gong, Shi-qiang; Niu, Li-Na; Kemp, Lisa K; Yiu, Cynthia K Y; Ryou, Heonjune; Qi, Yi-Pin; Blizzard, John D; Nikonov, Sergey; Brackett, Martha G; Messer, Regina L W; Wu, Christine D; Mao, Jing; Bryan Brister, L; Rueggeberg, Frederick A; Arola, Dwayne D; Pashley, David H; Tay, Franklin R

    2012-09-01

    The design of antimicrobial polymers to address healthcare issues and minimize environmental problems is an important endeavor with both fundamental and practical implications. Quaternary ammonium silane-functionalized methacrylate (QAMS) represents an example of antimicrobial macromonomers synthesized by a sol-gel chemical route; these compounds possess flexible Si-O-Si bonds. In present work, a partially hydrolyzed QAMS co-polymerized with 2,2-[4(2-hydroxy 3-methacryloxypropoxy)-phenyl]propane is introduced. This methacrylate resin was shown to possess desirable mechanical properties with both a high degree of conversion and minimal polymerization shrinkage. The kill-on-contact microbiocidal activities of this resin were demonstrated using single-species biofilms of Streptococcus mutans (ATCC 36558), Actinomyces naeslundii (ATCC 12104) and Candida albicans (ATCC 90028). Improved mechanical properties after hydration provided the proof-of-concept that QAMS-incorporated resin exhibits self-repair potential via water-induced condensation of organic modified silicate (ormosil) phases within the polymerized resin matrix. PMID:22659173

  8. Growth and pigment development of Dunaliella salina Teod. in response to ammonium nitrate nutrition

    Directory of Open Access Journals (Sweden)

    Keramatollah Nikookar

    2013-09-01

    Full Text Available The microalgae, Dunaliella salina was isolated from Maharlu Salt Lake, south east of Shiraz, Iran. The isolated strain was identified by both morphological and physiological markers. The complete ITS region (ITS1 + ITS2 including the 5.8S rDNA gene used as molecular marker confirmed our identification. Growth and cell proliferation, total chlorophyll and carotenoid contents were determined in the presence of 0.125, 0.25, 0.50, 1.0 and 2.0 mM ammonium nitrate. After five weeks, a maximum cell density of about (4.4 ±0.21×106 mL-1 was observed in the growth medium containing 1mM NH4NO3. Increasing NH4NO3 concentrations up to 1mM, resulted in an increase in the cells total chlorophyll contents. The highest amount of cell carotenoid contents was produced in media containing the least amount of NH4NO3 (0.125 mM. Manipulating the type and amount of external nitrogen sources to induce the synthesis of the highest amounts of carotenoid compounds in this microalgae strain can be of great commercial values to food industries.

  9. Flame Retardancy and Mechanical Properties of Kenaf Filled Polypropylene (PP) Containing Ammonium Polyphosphate (APP)

    International Nuclear Information System (INIS)

    The effects of ammonium polyphosphate (APP) as flame retardant and kenaf as fillers on flammability, thermal and mechanical properties of polypropylene (PP) composites were determined. Test specimens were prepared by using a co-rotating twin screw extruder for the compounding process followed by injection molding. The flame retardancy of the composites was determined by using limiting oxygen index (LOI) test. Addition of flame retardant into kenaf-PP composites significantly increased the LOI values that indicated the improvement of flame retardancy. Thermogravimetric analysis was done to examine the thermal stability of the composites. The addition of kenaf fiber in PP composites decreased the thermal stability significantly but the influence of APP on thermal properties of the kenaf-filled PP composites was not significant. The flexural strength and modulus of composites increased with the addition of APP into kenaf filled PP composite. The addition of APP into kenaf filled PP causes increase in the impact strength while increasing the APP content in the kenaf filled PP composite show decrease in impact strength. (author)

  10. Biomarker expression in lung of rabbit with pulmonary fibrosis induced by ammonium perchlorate.

    Science.gov (United States)

    Wu, Feng-hong; Guo, Hui-xia; Lin, Ming-fang; Chen, Zhi-ze; Zhou, Xuan; Peng, Kai-liang

    2011-04-01

    Ammonium perchlorate (AP), an oxidizer, has been used in solid propellants. Although AP exposure has been suspected as a risk factor for the development of pulmonary fibrosis, data are still inconclusive. To evaluate the pulmonary toxicity and the potential pulmonary fibrosis caused by occupational exposure to this compound, 25 male rabbits were randomly allocated into five groups to receive AP or bleomycin or saline by intratracheal injection. All rabbits were sacrificed and total RNA from the lungs was extracted. Expressions of types I and III collagens, transforming growth factor-β(1) (TGF-β(1)) and tumour necrosis factor-α (TNF-α) messenger RNA (mRNA) were measured by reverse transcription-polymerase chain reaction (RT-PCR). The expressions of type I and III collagen mRNA in low, moderate and high dose AP groups were significantly higher (p < 0.01 or p < 0.05) than that in the saline group. There was also a significant increased level of TGF-β(1) and TNF-α mRNA in the three AP groups compared with saline control group (p < 0.01 or p < 0.05). These results reveal that AP can increase gene expressions of types I, III collagens, TGF-β(1) and TNF-α in lung of rabbits exposed to AP. The overexpression of these biomarkers were considered as effective indicator linking to the development of pulmonary fibrosis and finally demonstrated that AP has potential to induce pulmonary fibrosis.

  11. On the anomalous decomposition and reactivity of ammonium and potassium dinitramide.

    Science.gov (United States)

    Rahm, Martin; Brinck, Tore

    2010-03-01

    Mechanistic pathways for the thermal decomposition of the solid-state energetic oxidizers ammonium dinitramide (ADN) and potassium dinitramide (KDN) have been deciphered by carefully considering previously performed experimental studies and using state of the art quantum chemical modeling of molecular clusters. Decomposition is governed by surface chemical processes, involving polarized (twisted) dinitramide anions of reduced stability. Under atmospheric and low-pressure conditions, the rate-determining step for the decomposition of these dinitramide salts is the dissociation into NO(2) and NNO(2)(-) radicals. The activation barriers for these steps are estimated to be 30 and 36 kcal/mol for ADN and KDN, respectively. The known stabilizing effect of water is explained by its hydrogen bonding ability, which counteracts polarization of surface dinitramides. The reactivity of ADN toward various chemical environments is likely explained through metastable decomposition radical intermediates. Donation of hydrogen bonds, antioxidant character, and basicity are properties believed to correlate with a compound's ability to act as a stabilizer for dinitramide salts. PMID:20143828

  12. Electron Shuttles Enhance Anaerobic Ammonium Oxidation Coupled to Iron(III) Reduction.

    Science.gov (United States)

    Zhou, Guo-Wei; Yang, Xiao-Ru; Li, Hu; Marshall, Christopher W; Zheng, Bang-Xiao; Yan, Yu; Su, Jian-Qiang; Zhu, Yong-Guan

    2016-09-01

    Anaerobic ammonium oxidation coupled to iron(III) reduction, termed Feammox, is a newly discovered nitrogen cycling process. However, little is known about the roles of electron shuttles in the Feammox reactions. In this study, two forms of Fe(III) (oxyhydr)oxide ferrihydrite (ex situ ferrihydrite and in situ ferrihydrite) were used in dissimilatory Fe(III) reduction (DIR) enrichments from paddy soil. Evidence for Feammox in DIR enrichments was demonstrated using the (15)N-isotope tracing technique. The extent and rate of both the (30)N2-(29)N2 and Fe(II) formation were enhanced when amended with electron shuttles (either 9,10-anthraquinone-2,6-disulfonate (AQDS) or biochar) and further simulated when these two shuttling compounds were combined. Although the Feammox-associated Fe(III) reduction accounted for only a minor proportion of total Fe(II) formation compared to DIR, it was estimated that the potentially Feammox-mediated N loss (0.13-0.48 mg N L(-1) day(-1)) was increased by 17-340% in the enrichments by the addition of electron shuttles. The addition of electron shuttles led to an increase in the abundance of unclassified Pelobacteraceae, Desulfovibrio, and denitrifiers but a decrease in Geobacter. Overall, we demonstrated a stimulatory effect of electron shuttles on Feammox that led to higher N loss, suggesting that electron shuttles might play a crucial role in Feammox-mediated N loss from soils. PMID:27494694

  13. Studies on a Cationically Modified Quaternary Ammonium Salt of Lignin

    Institute of Scientific and Technical Information of China (English)

    YANG Ai-li; JIANG Wen-ju

    2007-01-01

    A new quaternary ammonium salt monomer was synthesized and a quaternary amination of lignin( noted as QL),with the monomer was carried out by grafting copolymerization. The products were characterized by Fourier Transform Infrared spectroscopy(FTIR). The experimental results indicate that the yield of the monomer was 99.06%, and the conversion of the monomer and the grafting yield of QL were 93.69% and 185.78%, respectively. The feasibility of QL as the fiocculant to be applied in color removal of five artificial dyes, eriochrome black T( dye A), gongo red( dye B), direct fast black G (dye C), cuprofix blue green B (dye D), and acid black ATT (dye E) was examined.Results show that QL exhibits the favorable flocculation performance and high stability.

  14. Crystal structure of tris-(hydroxyl-ammonium) orthophosphate.

    Science.gov (United States)

    Leinemann, Malte; Jess, Inke; Boeckmann, Jan; Näther, Christian

    2015-11-01

    The crystal structure of the title salt, ([H3NOH](+))3·[PO4](3-), consists of discrete hydroxyl-ammonium cations and ortho-phos-phate anions. The atoms of the cation occupy general positions, whereas the anion is located on a threefold rotation axis that runs through the phospho-rus atom and one of the phosphate O atoms. In the crystal structure, cations and anions are linked by inter-molecular O-H⋯O and N-H⋯O hydrogen bonds into a three-dimensional network. Altogether, one very strong O-H⋯O, two N-H⋯O hydrogen bonds of medium strength and two weaker bifurcated N-H⋯O inter-actions are observed. PMID:26594525

  15. Polishing of quartz by rapid etching in ammonium bifluoride.

    Science.gov (United States)

    Vallin, Orjan; Danielsson, Rolf; Lindberg, Ulf; Thornell, Greger

    2007-07-01

    The etch rate and surface roughness of polished and lapped AT-cut quartz subjected to hot (90, 110, and 130 degrees C), concentrated (50, 65, 80 wt %) ammonium bi-fluoride have been investigated. Having used principal component analysis to verify experimental solidity and analyze data, we claim with confidence that this parameter space does not, as elsewhere stated, allow for a polishing effect or even a preserving setting. Etch rates were found to correlate well, and possibly logarithmically, with temperature except for the hottest etching applied to lapped material. Roughness as a function of temperature and concentration behaved well for the lapped material, but lacked systematic variation in the case of the polished material. At the lowest temperature, concentration had no effect on etch rate or roughness. Future efforts are targeted at temperatures and concentrations closer to the solubility limit.

  16. A facile synthesis of ω-aminoalkyl ammonium hydrogen phosphates

    Institute of Scientific and Technical Information of China (English)

    Wei Bo Kong; Xiao Yong Zhou; Yang Yang; Xing Yi Xie

    2012-01-01

    A series of ω-aminoalkyl ammonium hydrogen phosphates were synthesized through a simple and efficient three-step method.The starting materials,ω-aminoalkyl alcohols (AC-n,with carbon number n =3,4,5,6),were amino-protected with 9-fluorenylmethyl chloroformate (Fmoc-Cl),followed by phosphorylation with POCl3 and deprotection in piperidine/DMF The structures of each intermediate and final product were confirmed by 1H NMR,FTIR and mass spectrum.The yield of each step was about 77-92%,with a total yield higher than 56%.This new method was superior in low-cost raw materials,mild reaction temperatures (0-25 ℃) and easy purification methods.

  17. Hibiscus sabdariffa Affects Ammonium Chloride-Induced Hyperammonemic Rats

    Directory of Open Access Journals (Sweden)

    M. Mohamed Essa

    2007-01-01

    Full Text Available Hibiscus sabdariffa (HS is an edible medicinal plant, indigenous to India, China and Thailand and is used in Ayurveda and traditional medicine. Alcoholic extract of HS leaves (HSEt was studied for its anti-hyperammonemic and antioxidant effects in brain tissues of ammonium chloride-induced hyperammonemic rats. Oral administration of HSEt (250 mg kg−1 body weight significantly normalizes the levels of ammonia, urea, uric acid, creatinine and non-protein nitrogen in the blood. HSEt significantly reduced brain levels of lipid peroxidation products such as thiobarbituric acid and reactive substances (TBARS and hydroperoxides (HP. However, the administered extract significantly increased the levels of antioxidants such as catalase (CAT, superoxide dismutase (SOD, glutathione peroxidase (GPx and reduced glutathione (GSH in brain tissues of hyperammonemic rats. This investigation demonstrates significant anti-hyperammonemic and antioxidant activity of HS.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-05-17

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

  19. 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.

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

    Science.gov (United States)

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

    2012-12-01

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

  1. Clinoptilolite-based mixed matrix membranes for the selective recovery of potassium and ammonium

    NARCIS (Netherlands)

    Casadella, A.; Kuntke, P.; Schaetzle, O.; Loos, K.

    2016-01-01

    . A clinoptilolite-based mixed matrix membrane (MMM) was developed and studied for the selective recovery of ammonium and potassium. Adsorption of sodium (Na+), potassium (K+) and ammonium (NH4+) was investigated with single salt and equimolar salt solution under static and dynamic conditions. Furth

  2. 75 FR 56489 - Separation Distances of Ammonium Nitrate and Blasting Agents From Explosives or Blasting Agents...

    Science.gov (United States)

    2010-09-16

    ... definition of ammonium nitrate fertilizer issued by the Fertilizer Institute'' in its ``Definition and Test Procedures for Ammonium Nitrate Fertilizer.'' The Fertilizer Institute (TFI) ] is a voluntary, non-profit trade association of the fertilizer industry that currently has more than 175 members. See...

  3. 76 FR 23569 - Termination of the Suspension Agreement on Solid Fertilizer Grade Ammonium Nitrate From the...

    Science.gov (United States)

    2011-04-27

    ... Antidumping Duty Investigation: Solid Fertilizer Grade Ammonium Nitrate from the Russian Federation, 64 FR... Less Than Fair Value: Solid Fertilizer Grade Ammonium Nitrate from the Russian Federation, 65 FR 1139... International Trade Administration Termination of the Suspension Agreement on Solid Fertilizer Grade...

  4. Photo-Fenton-like degradation of azo dye methyl orange using synthetic ammonium and hydronium jarosite

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Zhihui [Department of Chemistry, College of Science, Nanjing Agricultural University, Nanjing 210095 (China); Liang, Jianru [Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Zhou, Lixiang, E-mail: lxzhou@njau.edu.cn [Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China)

    2013-01-05

    Highlights: Black-Right-Pointing-Pointer Hydronium and ammonium jarosite could catalyze the oxidation of methyl orange in photo-Fenton-like process. Black-Right-Pointing-Pointer The oxidation process is essentially heterogeneous, not homogeneous. Black-Right-Pointing-Pointer Hydronium jarosite has stronger reactivity than ammonium jarosite. - Abstract: Ammonium and hydronium jarosite were prepared by hydrothermal method with urea as the homogeneous precipitant. X-ray diffraction, field-emission scanning electron microscope, X-ray photoelectron spectrum, UV-vis spectra and fourier transform infrared spectrum were used to characterize the resulting products. The photodegradation efficiency of the prepared ammonium and hydronium jarosite was studied in a photo-Fenton-like process using methyl orange (MO) as target pollutant. The photocatalytic degradation of MO over synthetic ammonium and hydronium jarosite under various conditions, such as catalysts loading, H{sub 2}O{sub 2} concentration and initial pH, has been investigated. Results show that ammonium and hydronium jarosite have satisfactory photocatalysis effect in degradation of MO azo dye, and that the reactivity of hydronium jarosite toward the mineralization of MO was higher than that of ammonium jarosite. The novel ammonium and hydronium jarosite catalysts would be important for industrial applications due to their high photoactivity, little iron leaching and low cost.

  5. Ammonium across a Selective Polymer Inclusion Membrane : Characterization, Transport, and Selectivity

    NARCIS (Netherlands)

    Casadella, Anna; Schaetzle, Olivier; Loos, Katja

    2016-01-01

    The recovery of ammonium from urine requires distinguishing and excluding sodium and potassium. A polymer inclusion membrane selective for ammonium is developed using an ionophore based on pyrazole substituted benzene. The interactions of the components are studied, as well as their effect on transp

  6. Temperature effects in the absorption spectra and exciton luminescence in ammonium halides

    International Nuclear Information System (INIS)

    Warm-up behavior of the first maximum exciton absorption bands in ammonium halides is explored. Under phase transition occurs offset of bands, bound both with changing a parameter of lattice, and efficient mass of exciton. Warm-up dependency of quantum leaving a luminescence of self-trapped excitons in ammonium halides is measured. (author)

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

    NARCIS (Netherlands)

    Maesen, Th.J.M.

    1953-01-01

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

  8. Effects of Ammonium and Nitrite on Growth and Competitive Fitness of Cultivated Methanotrophic Bacteria▿

    OpenAIRE

    Nyerges, Györgyi; Han, Suk-Kyun; Stein, Lisa Y.

    2010-01-01

    The effects of nitrite and ammonium on cultivated methanotrophic bacteria were investigated. Methylomicrobium album ATCC 33003 outcompeted Methylocystis sp. strain ATCC 49242 in cultures with high nitrite levels, whereas cultures with high ammonium levels allowed Methylocystis sp. to compete more easily. M. album pure cultures and cocultures consumed nitrite and produced nitrous oxide, suggesting a connection between denitrification and nitrite tolerance.

  9. Ammonium-oxidizing bacteria facilitate aerobic degradation of sulfanilic acid in activated sludge.

    Science.gov (United States)

    Chen, Gang; Ginige, Maneesha P; Kaksonen, Anna H; Cheng, Ka Yu

    2014-01-01

    Sulfanilic acid (SA) is a toxic sulfonated aromatic amine commonly found in anaerobically treated azo dye contaminated effluents. Aerobic acclimatization of SA-degrading mixed microbial culture could lead to co-enrichment of ammonium-oxidizing bacteria (AOB) because of the concomitant release of ammonium from SA oxidation. To what extent the co-enriched AOB would affect SA oxidation at various ammonium concentrations was unclear. Here, a series of batch kinetic experiments were conducted to evaluate the effect of AOB on aerobic SA degradation in an acclimatized activated sludge culture capable of oxidizing SA and ammonium simultaneously. To account for the effect of AOB on SA degradation, allylthiourea was used to inhibit AOB activity in the culture. The results indicated that specific SA degradation rate of the mixed culture was negatively correlated with the initial ammonium concentration (0-93 mM, R²= 0.99). The presence of AOB accelerated SA degradation by reducing the inhibitory effect of ammonium (≥ 10 mM). The Haldane substrate inhibition model was used to correlate substrate concentration (SA and ammonium) and oxygen uptake rate. This study revealed, for the first time, that AOB could facilitate SA degradation at high concentration of ammonium (≥ 10 mM) in an enriched activated sludge culture.

  10. Suppression of interference in the AAS determination of chromium by use of ammonium bifluoride.

    Science.gov (United States)

    Purushottam, A; Naidu, P P; Lal, S S

    1973-07-01

    Addition of 1% of ammonium bifluoride successfully suppresses interference by diverse ions in the atomic-absorption determination of chromium(VI). If the sample solutions also contain chromium(III) addition of 1% of ammonium bifluoride and 0.2% of sodium sulphate is recommended for the suppression.

  11. Irritant contact dermatitis due to ammonium bifluoride in two infant twins.

    Science.gov (United States)

    Toledo, Fernando; Silvestre, Juan Francisco; Cuesta, Laura; Bañuls, José

    2013-01-01

    Ammonium bifluoride is one of the most corrosive acids that may produce severe chemical burns when in contact with skin. This hazardous chemical is widely used in household products. We report two pediatric cases of irritant contact dermatitis after exposure to a rust remover, which contained ammonium bifluoride.

  12. Effect of quaternary ammonium salts on flotation behavior of aluminosilicate minerals

    Institute of Scientific and Technical Information of China (English)

    ZHAO Sheng-gui; ZHONG Hong; LIU Guang-yi

    2007-01-01

    The electrokinetic properties and flotation of diaspore, kaolinite, pyrophyllite and illite with quaternary ammonium salts collectors were studied. The results of flotation tests show that the collecting ability of quaternary ammonium salts for the four minerals is in the order(from strong to weak) of octadecyl dimethyl benzyl ammonium chloride(ODBA), cetyl trimethyl ammonium bromide(CTAB), dodecyl trimethyl ammonium chloride(DTAC). Under the condition of alkalescence, it is possible to separate the diaspore from the silicate minerals such as kaolinite, illite and pyrophyllite using quaternary ammonium salts as collector. Isoelectric points (IEP) of diaspore, kaolinite, pyrophyllite and illite are pH=6.0, 3.4, 2.3 and 3.2, respectively. Quaternary ammonium salts can change ζ-potential of the aluminosilicate minerals obviously. The flotation mechanisms were explained by ζ-potential and Fourier transform infrared spectrum (FT-IR) measurements. The results demonstrate that only electrostatic interaction takes place between aluminosilicate minerals (diaspore, kaolinite, pyrophyllite and illite) and quaternary ammonium salts.

  13. Ammonium addition inhibits 13C-methane incorporation into methanotroph membrane lipids in a freshwater sediment

    NARCIS (Netherlands)

    Nold, S.C.; Boschker, H.T.S.; Pel, R.; Laanbroek, H.J.

    1999-01-01

    To investigate the effect of ammonium addition on the species composition and activity of freshwater methane oxidizing bacteria, intact sediment cores were labeled with 13CH4 and incubated under ambient and elevated ammonium concentrations. After 7 days, methanotroph activity was assessed by quantif

  14. AMMONIUM TOXICITY AND NITRATE RESPONSE OF AXENICALLY GROWN DACTYLORHIZA-INCARNATA SEEDLINGS

    NARCIS (Netherlands)

    DIJK, E; ECK, N

    1995-01-01

    The response to ammonium- and nitrate-nitrogen of seedlings of the calcicole orchid species Dactylorhiza incarnata (L.) Soo was tested in axenic in vitro culture of c. 3-month-old protocorms. A pronounced toxicity of ammonium ions was observed. Seedlings raised from plants of a coastal population (f

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

    DEFF Research Database (Denmark)

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

    2008-01-01

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

  16. Nitrogen phosphoric fertilizer production technology on the base of Central Kyzylkum phosphorites and ammonium nitrate melt

    OpenAIRE

    Shavkat Namazov; Akhmed Reymov; Nazarkul Pirmanov; Rashid Kurbaniyazov

    2012-01-01

    The process of obtaining nitrogen phosphoric fertilizer by introduction Central Kyzylkum phosphates and ammonium nitrate melt is studied. On the base of these results production technology diagram for nitrogen phosphoric fertilizer is offered. The given technology was approved and developed at the functioning devices of OJSC “NAVOIAZOT” ammonium nitrate shop.

  17. Nitrogen phosphoric fertilizer production technology on the base of Central Kyzylkum phosphorites and ammonium nitrate melt

    Directory of Open Access Journals (Sweden)

    Shavkat Namazov

    2012-11-01

    Full Text Available The process of obtaining nitrogen phosphoric fertilizer by introduction Central Kyzylkum phosphates and ammonium nitrate melt is studied. On the base of these results production technology diagram for nitrogen phosphoric fertilizer is offered. The given technology was approved and developed at the functioning devices of OJSC “NAVOIAZOT” ammonium nitrate shop.

  18. Nitrogen removal by autotrophic ammonium oxidizing bacteria enrichment under anaerobic conditions

    Directory of Open Access Journals (Sweden)

    Pongsak (Lek Noophan

    2008-07-01

    Full Text Available Sludge from an anoxic tank at the centralized wastewater treatment plant, Nong Khaem, Bangkok, Thailand, was inoculatedin an anaerobic sequencing batch reactor (ASBR. The optimal compositions and operating conditions of the stock of autotrophic ammonium oxidizing bacteria medium were determined. The process of oxidizing ammonium with bacteria under anaerobic conditions is often referred to as the Anammox process (NO2- to N2 gas, using NH4+ as the electron donor and NO2- as the electron acceptor. The startup period for the anammox culture took more than three months. With ammoniumand nitrite concentration ratios of 1:1.38 and 1:1.6, the nitrogen conversion rate zero order. Fluorescent in situ hybridization(FISH was used to identify specific autotrophic ammonium oxidizing bacteria (Nitrosomonas spp., Candidatus Brocadia anammoxidans, and Candidatus Kuenenia stuttgartiensis. Results from this work demonstrated a shift in the species of ammonium oxidizing bacteria from Nitrosomonas spp. to Candidati Brocadia anammoxidans and Kuenenia stuttgartiensis, with increased ammonium concentrations from 3 mM to 15 mM. Under NH4+:NO2- ratios of 1:1.38 and 1:1.6 the ammoniumoxidizing bacteria were able to remove both ammonium and nitrite simultaneously. The specific nitrogen removal rate of theanammox bacteria (Candidati Brocadia anammoxidans and Kuenenia stuttgartiensis was significantly higher than that of anaerobic ammonium oxidizing bacteria (Nitrosomonas spp.. Anaerobic ammonium oxidizing bacteria (Candidati Brocadia anammoxidans and Kuenenia stuttgartiensis are strict anaerobes.

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

    CERN Document Server

    Cohen-Adad, R

    1991-01-01

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

  20. 77 FR 21527 - Ammonium Nitrate From Russia: Correction to Notice of Opportunity To Request Administrative Review

    Science.gov (United States)

    2012-04-10

    ...; Opportunity To Request Administrative Review, 77 FR 63 (April 2, 2012). This notice serves as a correction to... International Trade Administration Ammonium Nitrate From Russia: Correction to Notice of Opportunity To Request... of the antidumping duty orders and inadvertently omitted Ammonium Nitrate from Russia, POR...

  1. Ceric Ammonium Nitrate-Mediated Oxidative Cycloaddition of 1,3-Dicarbonyls to β-Aryl-α, β-unsaturated Ketones

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei; HUO Cong-De; LIU Zheng-Gang; LIU Zhong-Li

    2003-01-01

    @@ Oxidative addition of carbon-centred radicals to alkenes mediated by metal salts ( MnⅢ, CeⅣ, HgⅡ,PdⅣ, AgⅠ,and CuⅡ) has received considerable attention over last decade in organic synthesis for construction of carbon-carbon bond. [1,2] Among them, manganese(Ⅲ) acetate and ceric(Ⅳ) ammonium nitrate (CAN) have been use most efficiently. Recently, CAN-mediated oxidative cycloaddition of 1,3-dicarbonyl compounds to alkenes, conjugated compounds, enol silyl ethers and alkynes, has been studied extensively. We exploited that the CAN-mediated oxidative cycloaddition of 1,3-dicarbonyl compounds to β-aryl-α,β-unsaturated ketones afforded dihydrofuran derivatives in moderate yields. All the products were characterized by 1H NMR, 13C NMR, MS and HRMS spectra.

  2. Is it possible to screen for milk or whey protein adulteration with melamine, urea and ammonium sulphate, combining Kjeldahl and classical spectrophotometric methods?

    Science.gov (United States)

    Finete, Virgínia de Lourdes Mendes; Gouvêa, Marcos Martins; Marques, Flávia Ferreira de Carvalho; Netto, Annibal Duarte Pereira

    2013-12-15

    The Kjeldahl method and four classic spectrophotometric methods (Biuret, Lowry, Bradford and Markwell) were applied to evaluate the protein content of samples of UHT whole milk deliberately adulterated with melamine, ammonium sulphate or urea, which can be used to defraud milk protein and whey contents. Compared with the Kjeldahl method, the response of the spectrophotometric methods was unaffected by the addition of the nitrogen compounds to milk or whey. The methods of Bradford and Markwell were most robust and did not exhibit interference subject to composition. However, the simultaneous interpretation of results obtained using these methods with those obtained using the Kjeldahl method indicated the addition of nitrogen-rich compounds to milk and/or whey. Therefore, this work suggests a combination of results of Kjeldahl and spectrophotometric methods should be used to screen for milk adulteration by these compounds.

  3. Nontoxic, Inexpensive, Ammonium Chloride-Mediated (In Water) Synthesis of Some Novel 1,5-benzothiazepine Derivatives and Their Antimicrobial Activity

    International Nuclear Information System (INIS)

    In the present study, a new, nontoxic, easy and inexpensive method for the synthesis of 1,5-benzothiazepine derivatives was described and a mechanism for this reactions was proposed. Ammonium chloride which is inexpensive and readily available reagent catalyzes the thia-michael addition reaction of thiols in water efficiently. 1,5-benzothiazepines derivatives were synthesized by the condensation reactions of o-aminothiophenol (o-ATP) with chalcone derivatives by using saturated solution of NH/sub 4/Cl in water. The products were characterized by the elemental analysis, NMR and FT-IR techniques. Synthesized compounds were tested for antimicrobial activity against. Staphylococcus aureus ATCC 6538, Escherichia coli ATCC 25922, Bacillus subtilis IMG22 and Candida albicans ATCC 10231. Among the synthesized compounds 2b was found to be most active derivative against Escherichia coli ATCC 25922 and Candida albicans ATCC 10231. The other compounds didn't exhibit any activity against the other test microorganisms. (author)

  4. Electrochemical exfoliation of graphite in quaternary ammonium-based deep eutectic solvents: a route for the mass production of graphane.

    Science.gov (United States)

    Abdelkader, Amr M; Patten, Hollie V; Li, Zheling; Chen, Yiqiang; Kinloch, Ian A

    2015-07-14

    We demonstrate a facile and scalable electrochemical approach to exfoliate graphite, which permits in situ hydrogenation of the resultant graphene via a solvated NR(4+) graphite compound in quaternary ammonium-based deep eutectic solvents. Spectroscopic studies reveal the presence of sp(3) C-H bonds in the hydrogenated graphene. The resulting materials consist of micrometre-sized and predominantly monolayer to few layers thick hydrogenated graphenic flakes. A large band gap (∼4 eV) further establishes the high level of hydrogenation. It is also possible to tune the band gap introduced to the graphene by controlling the level of hydrogenation. The mechanism of the exfoliation and hydrogenation is also discussed. PMID:26074262

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

    Directory of Open Access Journals (Sweden)

    V.K. Gupta

    2015-04-01

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

  6. Kinetics Analysis on Mixing Calcination Process of Fly Ash and Ammonium Sulfate

    Institute of Scientific and Technical Information of China (English)

    Peng Wang; Laishi Li; Dezhou Wei

    2014-01-01

    abstract The further development of the extraction of alumina that is produced in the calcination process of ammonium sulfate mixed with fly ash was limited because of the lack of systematic theoretical study. In order to aggrandize the research of the calcination process, the kinetics and reaction mechanism of the calcinations were studied. The result suggests that there are two stages in the calcination process, and the alumina extraction rate increases swiftly in the initial stage, but slows down increasing in the later stage. The apparent activation energy of the initial and later stages equals to 13.31 and 35.65 kJ·mol-1, respectively. In the initial stage, ammonium sulfate reacts directly with mullite in the fly ash to form ammonium aluminum sulfate, while in the later stage, alumi-num sulfate is formed by the reaction between ammonium aluminum sulfate and ammonium sulfate.

  7. Nitrogen stable isotopes of ammonium and nitrate in high mountain lakes of the Pyrenees

    Directory of Open Access Journals (Sweden)

    M. Bartrons

    2009-12-01

    Full Text Available Nitrogen stable isotopes (δ15N are increasingly used to trace food web relationships and the flow of matter in lakes. However, there is high variability in δ15N among primary producers and other primary energy resources that can eventually propagate throughout the lake food web. To increase our understanding of the origin of this variability, we measured ammonium and nitrate δ15N in atmospheric deposition (AD, epilimnetic water (EW, deep chlorophyll maximum water (DCMW, and sediment porewater (SPW in eight mountain lakes. A general δ15N (−3.4‰ for AD was estimated as the signature for AD ammonium and nitrate did not differ. All lakes showed similar high δ15N-NH4+ values for SPW (ca. 2.2‰. In contrast, the variability among lakes in water column values was high, although differences between EW and DCMW within a lake were low. δ15N-NO3- correlated with the altitude of the lakes, and its variability was interpreted as the influence of catchment nitrification, which is higher in talus landscapes. δ15N-NH4+ distribution had two modes, positive values (ca. 3‰ were associated to DCMW of shallow lakes, and probably reflect the SPW influence. Lower values (ca. −3‰ occur in EW and DCMW of deep lakes, and its variability was related to the degree that NO3- was up taken by primary producers and recycled within the food-web when NH4+ availability was low compared to demand. Overall, altitude, lake depth and seasonal cumulative primary production largely explain the patterns of δ15N variability observed in nitrogen dissolved compounds.

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

    Science.gov (United States)

    Moreno-Marín, Francisco; Vergara, Juan J.; Pérez-Llorens, J. Lucas; Pedersen, Morten F.; Brun, Fernando G.

    2016-01-01

    Eutrophication affects seagrasses negatively by increasing light attenuation through stimulation of biomass of fast-growing, bloom-forming algae and because high concentrations of ammonium in the water can be toxic to higher plants. We hypothesized nevertheless, that moderate amounts of nitrophilic macroalgae that coexists with seagrasses under eutrophic conditions, can alleviate the harmful effects of eutrophication on seagrasses by reducing ammonium concentrations in the seawater to non-toxic levels because such algae have a very large capacity to take up inorganic nutrients. We studied therefore how combinations of different ammonium concentrations (0, 25 and 50 μM) and different standing stocks of macroalgae (i.e. 0, 1 and 6 layers of Ulva sp.) affected survival, growth and net production of the seagrass Zostera noltei. In the absence of Ulva sp., increasing ammonium concentrations had a negative influence on the performance of Z. noltei. The presence of Ulva sp. without ammonium supply had a similar, but slightly smaller, negative effect on seagrass fitness due to light attenuation. When ammonium enrichment was combined with presence of Ulva sp., Ulva sp. ameliorated some of negative effects caused by high ammonium availability although Ulva sp. lowered the availability of light. Benthic microalgae, which increased in biomass during the experiment, seemed to play a similar role as Ulva sp.–they contributed to remove ammonium from the water, and thus, aided to keep the ammonium concentrations experienced by Z. noltei at relatively non-toxic levels. Our findings show that moderate amounts of drift macroalgae, eventually combined with increasing stocks of benthic microalgae, may aid seagrasses to alleviate toxic effects of ammonium under eutrophic conditions, which highlights the importance of high functional diversity for ecosystem resistance to anthropogenic disturbance. PMID:27035662

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

    Science.gov (United States)

    Moreno-Marín, Francisco; Vergara, Juan J; Pérez-Llorens, J Lucas; Pedersen, Morten F; Brun, Fernando G

    2016-01-01

    Eutrophication affects seagrasses negatively by increasing light attenuation through stimulation of biomass of fast-growing, bloom-forming algae and because high concentrations of ammonium in the water can be toxic to higher plants. We hypothesized nevertheless, that moderate amounts of nitrophilic macroalgae that coexists with seagrasses under eutrophic conditions, can alleviate the harmful effects of eutrophication on seagrasses by reducing ammonium concentrations in the seawater to non-toxic levels because such algae have a very large capacity to take up inorganic nutrients. We studied therefore how combinations of different ammonium concentrations (0, 25 and 50 μM) and different standing stocks of macroalgae (i.e. 0, 1 and 6 layers of Ulva sp.) affected survival, growth and net production of the seagrass Zostera noltei. In the absence of Ulva sp., increasing ammonium concentrations had a negative influence on the performance of Z. noltei. The presence of Ulva sp. without ammonium supply had a similar, but slightly smaller, negative effect on seagrass fitness due to light attenuation. When ammonium enrichment was combined with presence of Ulva sp., Ulva sp. ameliorated some of negative effects caused by high ammonium availability although Ulva sp. lowered the availability of light. Benthic microalgae, which increased in biomass during the experiment, seemed to play a similar role as Ulva sp.--they contributed to remove ammonium from the water, and thus, aided to keep the ammonium concentrations experienced by Z. noltei at relatively non-toxic levels. Our findings show that moderate amounts of drift macroalgae, eventually combined with increasing stocks of benthic microalgae, may aid seagrasses to alleviate toxic effects of ammonium under eutrophic conditions, which highlights the importance of high functional diversity for ecosystem resistance to anthropogenic disturbance. PMID:27035662

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

    Directory of Open Access Journals (Sweden)

    Francisco Moreno-Marín

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

  11. Germination of some important weeds influenced by red light and nitrogenous compounds

    International Nuclear Information System (INIS)

    Seed dormancy is a major constraint in the eradication of weeds from agriculture fields. Seeds of Amaranthus retroflexus, Echinocloa crus-galli and Digitaria adscendens were collected from cultivated fields, dried and then treated with different nitrogen containing compounds i.e., potassium nitrate, ammonium chloride, ammonium nitrate and sodium nitrite. Some seeds were kept under dark while others were irradiated with red light for 10 min., after 12 hr of inhibition. The N-compounds were applied at the rate of 1, 5, 10, 25 and 50 mM, while the strength of red light pulse was maintained at 80 mu mols/sup -2/m/sup -1/. It was observed that red light significantly improved germination rates of A. retroflexus, E. crus-galli and D. adscendens. Nitrogenous compounds significantly improved germination of weeds and maximum germination was induced by ammonium nitrate. However, exposure of seeds to both red light and N-compounds provided significantly higher germination as compared to singular application of either of them. E. crusgalli recorded highest germination rates in response to red light and N-compounds, while D. adscendens provided least values for the same treatments. Application of N-compounds in conjunction with red light significantly improves germination rates of selected weed species by breaking their dormancy. (author)

  12. Specific interactions of functionalised gold surfaces with ammonium perchlorate or starch; towards a chemical cartography of their mixture

    Energy Technology Data Exchange (ETDEWEB)

    Mercier, D. [CNRS, UMR CNRS 7609, Laboratoire de Reactivite de Surface, Paris (France); Universite Pierre et Marie Curie - UPMC Paris VI, Laboratoire de Reactivite de Surface, 4 place Jussieu, 75252 Paris Cedex 05 (France); Laboratoire de recherche conventionne CEA/UPMC n Degree-Sign 1, Paris (France); Mercader, C.; Quere, S.; Hairault, L. [CEA, DAM, Le Ripault, F-37260 Monts (France); Laboratoire de recherche conventionne CEA/UPMC n Degree-Sign 1, Paris (France); Methivier, C. [CNRS, UMR CNRS 7609, Laboratoire de Reactivite de Surface, Paris (France); Universite Pierre et Marie Curie - UPMC Paris VI, Laboratoire de Reactivite de Surface, 4 place Jussieu, 75252 Paris Cedex 05 (France); Laboratoire de recherche conventionne CEA/UPMC n Degree-Sign 1, Paris (France); Pradier, C.M., E-mail: claire-Marie.pradier@upmc.fr [CNRS, UMR CNRS 7609, Laboratoire de Reactivite de Surface, Paris (France); Universite Pierre et Marie Curie - UPMC Paris VI, Laboratoire de Reactivite de Surface, 4 place Jussieu, 75252 Paris Cedex 05 (France); Laboratoire de recherche conventionne CEA/UPMC n Degree-Sign 1, Paris (France)

    2012-10-01

    Highlights: Black-Right-Pointing-Pointer Measurements of interactions by Quartz Crystal Microbalance. Black-Right-Pointing-Pointer AFM and CFM measurements, tip functionalisation. Black-Right-Pointing-Pointer Surface nano-imaging. - Abstract: By functionalising gold samples, planar wafers or AFM tips, with an acid- or an amino acid-terminated thiols, mercaptoundecanoic acid (MUA) and homocystein (H-Cyst) respectively, we were able to differentiate the interactions with ammonium perchlorate (AP) and starch (S), two components of a nanocomposition mixture. To do so, the interaction between gold functionalized surfaces and the two targeted compounds have been characterized and quantified by several complementary techniques. Polarisation modulation-infrared spectroscopy (PM-IRRAS), and X-ray photoelectron spectroscopy (XPS), providing chemical analyses of gold surfaces after contacting S or AP, proved that both compounds were retained on MUA or H-Cyst-modified surfaces, but to various extents. Quartz crystal microbalance on-line measurements enabled to monitor the kinetics of interaction and showed distinct differences in the behaviour of MUA and H-Cyst-surfaces towards the two compounds. Having observed that only H-Cyst-modified surfaces enables to get a contrast on the chemical force microscopy (CFM) images, this new result could be well explained by examining the data obtained by combining the above-mentioned surface characterisation techniques.

  13. Specific interactions of functionalised gold surfaces with ammonium perchlorate or starch; towards a chemical cartography of their mixture

    Science.gov (United States)

    Mercier, D.; Mercader, C.; Quere, S.; Hairault, L.; Méthivier, C.; Pradier, C. M.

    2012-10-01

    By functionalising gold samples, planar wafers or AFM tips, with an acid- or an amino acid-terminated thiols, mercaptoundecanoic acid (MUA) and homocystein (H-Cyst) respectively, we were able to differentiate the interactions with ammonium perchlorate (AP) and starch (S), two components of a nanocomposition mixture. To do so, the interaction between gold functionalized surfaces and the two targeted compounds have been characterized and quantified by several complementary techniques. Polarisation modulation-infrared spectroscopy (PM-IRRAS), and X-ray photoelectron spectroscopy (XPS), providing chemical analyses of gold surfaces after contacting S or AP, proved that both compounds were retained on MUA or H-Cyst-modified surfaces, but to various extents. Quartz crystal microbalance on-line measurements enabled to monitor the kinetics of interaction and showed distinct differences in the behaviour of MUA and H-Cyst-surfaces towards the two compounds. Having observed that only H-Cyst-modified surfaces enables to get a contrast on the chemical force microscopy (CFM) images, this new result could be well explained by examining the data obtained by combining the above-mentioned surface characterisation techniques.

  14. Determination of diethanolamine or N-methyldiethanolamine in high ammonium concentration matrices by capillary electrophoresis with indirect UV detection: application to the analysis of refinery process waters

    Energy Technology Data Exchange (ETDEWEB)

    Bord, N.; Cretier, G.; Rocca, J.-L. [Universite Claude Bernard Lyon 1 (France). Laboratoire des Sciences Analytiques; Bailly, C. [Centre de Recherches de Gonfreville, Total France, Laboratoires Chromatographie Liquide et Microbiologie, Rogerville (France); Souchez, J.-P. [Centre de Recherches de Solaize, Total France, Chemin du Canal, BP 22, St-Symphorien d' Ozon (France)

    2004-09-01

    Alkanolamines such as diethanolamine (DEA) and N-methyldiethanolamine (MDEA) are used in desulfurization processes in crude oil refineries. These compounds may be found in process waters following an accidental contamination. The analysis of alkanolamines in refinery process waters is very difficult due to the high ammonium concentration of the samples. This paper describes a method for the determination of DEA in high ammonium concentration refinery process waters by using capillary electrophoresis (CE) with indirect UV detection. The same method can be used for the determination of MDEA. Best results were achieved with a background electrolyte (BGE) comprising 10 mM histidine adjusted to pH 5.0 with acetic acid. The development of this electrolyte and the analytical performances are discussed. The quantification was performed by using internal standardization, by which triethanolamine (TEA) was used as internal standard. A matrix effect due to the high ammonium content has been highlighted and standard addition was therefore used. The developed method was characterized in terms of repeatability of migration times and corrected peak areas, linearity, and accuracy. Limits of detection (LODs) and quantification (LOQs) obtained were 0.2 and 0.7 ppm, respectively. The CE method was applied to the determination of DEA or MDEA in refinery process waters spiked with known amounts of analytes and it gave excellent results, since uncertainties obtained were 8 and 5%, respectively. (orig.)

  15. Synthesis and Structure of Supramolecular Compound with Ethyl 2-(4-Aminophenoxy)acetate Based on 18-Crown-6%Synthesis and Structure of Supramolecular Compound with Ethyl 2-(4-Aminophenoxy)acetate Based on 18-Crown-6

    Institute of Scientific and Technical Information of China (English)

    王文祥; 孙素文; 熊仁根

    2012-01-01

    The title ammonium compound ethyl 2-(4-aminophenoxy)acetate (C10 H13NO3, I) and its crown ether inclusion complex {[(CIoHI4NO3)·(18-crown-6)]·[PF6] , II} (18-crown-6 = 1,4,7,10,13,16-hexaoxacyclo-octadecane) were synthesized. The ammonium compound I was determined by 11-t NMR, IR and ESI-MS techiniques. X-ray crystal- lography reveals that compound I crystallizes in the triclinic system with space group of P-l, all the atoms in | are almost coplanar except H, and N--H…O hydrogen bonds lead to the formation of one dimensional chain. The ro- tator-stator-like compound 11 was crystallizes in the centrosymmetric monoclinic system with space group of P21/c. The supramolecular was formed via N--H…O hydrogen-bond interactions. Temperature-dependent dielectric constants of compound II were measured.

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

    NARCIS (Netherlands)

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

    1995-01-01

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

  17. A Combined Experimental and Theoretical Study of the Ammonium Bifluoride Catalyzed Regioselective Synthesis of Quinoxalines and Pyrido[2,3-b]pyrazines

    OpenAIRE

    Lassagne, Frédéric; Chevallier, Floris; Roisnel, Thierry; Dorcet, Vincent; Mongin, Florence; Domingo, Luis .R.

    2015-01-01

    International audience; Ammonium bifluoride was efficiently used (at a 0.5 mol % loading) to catalyze the cyclocondensation between 1,2-arylenediamines and 1,2-dicarbonyl compounds at room temperature in methanol-water, affording quinoxalines and pyrido[2,3-b]pyrazines in excellent yields. Importantly, 2,8-disubstituted quinoxalines and 3-substituted pyrido[2,3-b]pyrazines were regioselectively formed by reacting aryl glyoxals with 3-methyl-1,2-phenylenediamine and 2,3-diaminopyridine, respec...

  18. Environmental Factors Affecting Ammonium Oxidation Under Iron Reducing Conditions

    Science.gov (United States)

    Jaffe, P. R.; Huang, S.; Ruiz-Urigüen, M.

    2014-12-01

    Ammonium (NH4+) oxidation coupled to iron (Fe) reduction in the absence of oxygen and nitrate/nitrite (NO3-/NO2-) has been reported by several investigators and referred to as Feammox. Feammox is a biological reaction, where Fe(III) is the electron acceptor, which is reduced to Fe(II), and NH4+ is the electron donor, which is oxidized to NO2-. Through a 180-day anaerobic incubation experiment, and using PCR-DGGE, 454-pyosequecing and qPCR analysis, we have shown that an Acidimicrobiaceae bacterium A6, a previously unreported species in the Acidimicrobiaceae family, might be either responsible or plays a key role in the Feammox process, We have enriched these Feammox bacteria (65.8% in terms of cell numbers) in a membrane reactor, and isolated the pure Acidimicrobiaceae bacterium A6 strain in an autotrophic medium. In samples collected and then incubated from a series of local wetland-, upland-, as well as storm-water detention pond-sediments, Feammox activity was only detected in acidic soil environments that contain Fe oxides. Using primers we developed for this purpose, Acidimicrobiaceae bacterium A6 was detected in all incubations where Feammox was observed. Anaerobic incubations of Feammox enrichment cultures adjusted to different pH, revealed that the optimal pH for Feammox is 4 ~ 5, and the reaction does not proceed when pH > 7. Feammox was still proceeding at pH as low as 2. In Feammox culture amended with different Fe(III) sources, Feammox reaction proceeded only when Fe oxides (ferrihydrite or goethite ) were supplied, whereas samples incubated with ferric chloride or ferric citrate showed no measurable NH4+ oxidation. Furthermore, we have also determined from incubation experiments conducted with a temperature gradient (10 ~ 35℃), that the Feammox process was active when the temperature is above 15℃, and the optimal temperature is 20℃. Incubations of enrichment culture with 79% Feammox bacteria appeared to remove circa 8% more NH4+ at 20ºC than at

  19. Volatile Organic Compounds (VOCs)

    Science.gov (United States)

    ... Organic Compounds' Impact on Indoor Air Quality Volatile Organic Compounds' Impact on Indoor Air Quality On this page: ... Exposure Standards or Guidelines Additional Resources Introduction Volatile organic compounds (VOCs) are emitted as gases from certain solids ...

  20. Synthesis and Antimicrobial Properties of the Novel Fluorinated Bis-ammonium Salts with Two Primary Amine Groups

    Institute of Scientific and Technical Information of China (English)

    Jian Bin LUO; Qiang WANG; Hong TAN; Jie Hua LI; Yin Ping ZHONG

    2006-01-01

    In order to resolve the increasing resistance phenomena of the Gram-negative bacteria against single chain quaternary ammonium salts (QAS), lysine with a pedant fluorinated bis-ammonium salts was synthesized and its antimicrobial properties were evaluated in this work.The novel fluorinated bis-ammonium salts shows similar activity with conventional single chain quaternary ammonium salts against Gram-positive bacteria but stronger activity against Gram-negative bacteria and yeast compared with the single chained counterpart.

  1. Relating dynamic conditions to the performance of biological rapid sand filters used to remove ammonium, iron, and manganese from drinking water

    DEFF Research Database (Denmark)

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

    and media samples were collected throughout the depth of the column and over the operational cycle of the columns. Substrate analysis included ammonium, nitrite, nitrate, iron, and manganese. Qpcr analysis were also performed to quantify ammonium oxidizing bacteria (AOBs), ammonium oxidizing archea ( AOAs...... on the roles of both Ammonium oxidizing bacteria (AOBs) and Ammonium oxidizing archea (AOAs) in the biological removal of ammonium in rapid sand filters and how varying substrate loadings and operating conditions can affect the biological performance of these filters....

  2. Paleosols in central Illinois as potential sources of ammonium in groundwater

    Science.gov (United States)

    Glessner, J.J.G.; Roy, W.R.

    2009-01-01

    Glacially buried paleosols of pre-Holocene age were evaluated as potential sources for anomalously large concentrations of ammonium in groundwater in East Central Illinois. Ammonium has been detected at concentrations that are problematic to water treatment facilities (greater than 2.0 mg/L) in this region. Paleosols characterized for this study were of Quaternary age, specifically Robein Silt samples. Paleosol samples displayed significant capacity to both store and release ammonium through experiments measuring processes of sorption, ion exchange, and weathering. Bacteria and fungi within paleosols may significantly facilitate the leaching of ammonium into groundwater by the processes of assimilation and mineralization. Bacterial genetic material (DNA) was successfully extracted from the Robein Silt, purified, and amplified by polymerase chain reaction to produce 16S rRNA terminal restriction fragment length polymorphism (TRFLP) community analyses. The Robein Silt was found to have established diverse and viable bacterial communities. 16S rRNA TRFLP comparisons to well-known bacterial species yielded possible matches with facultative chemolithotrophs, cellulose consumers, nitrate reducers, and actinomycetes. It was concluded that the Robein Silt is both a source and reservoir for groundwater ammonium. Therefore, the occurrence of relatively large concentrations of ammonium in groundwater monitoring data may not necessarily be an indication of only anthropogenic contamination. The results of this study, however, need to be placed in a hydrological context to better understand whether paleosols can be a significant source of ammonium to drinking water supplies. ?? 2009 National Ground Water Association.

  3. Preparation and characteristic research of anhydrous magnesium chloride with dehydrated ammonium carnallite

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ning-bo; CHEN Bai-zhen; HE Xin-kuai; LI Yi-bing

    2006-01-01

    Taking the saline lake bischofite and NH4Cl that was removed with the ammonia method and continuwas synthesized. And then the ammonium carnallite was dehydrated to some extent at 160℃ for 4 h. Ammonium carnallite reacted with ammonia at 240℃ for 150 min and the ammonation ammonium carnallite was produced. Finally, the ammonation ammonium carnallite was calcined at 750℃ into anhydrous magnesium chloride containing only 0.1% (mass fraction) of MgO. On the other hand, dehydrated ammonium carnallite was mixed with the solid ammonium chloride at mass ratio 1:4 at high temperature and with the differential pressure of HN3 above 30.5 kPa. The dehydrated ammonium carnallite of mixture was dehydrated at 410℃, and then calcined at 700℃ into anhydrous magnesium chloride with only 0. 087% (mass fraction) of MgO. X-ray diffraction and electron microscopy analysis results prove that anhydrous magnesium chloride obtained by both methods hasn't mixed phases, the particle is large and even has good dispersion, which is suitable for preparation of metal magnesium in the electrolysis.

  4. Coastal water column ammonium and nitrite oxidation are decoupled in summer

    Science.gov (United States)

    Heiss, Elise M.; Fulweiler, Robinson W.

    2016-09-01

    Water column nitrification is a key process in the nitrogen cycle as it links reduced and oxidized forms of nitrogen and also provides the substrate (nitrate) needed for reactive nitrogen removal by denitrification. We measured potential water column ammonium and nitrite oxidation rates at four sites along an estuary to continental shelf gradient over two summers. In most cases, nitrite oxidation rates outpaced ammonium oxidation rates. Overall, ammonium and nitrite oxidation rates were higher outside of the estuary, and this trend was primarily driven by higher oxidation rates in deeper waters. Additionally, both ammonium and nitrite oxidation rates were impacted by different in situ variables. Ammonium oxidation rates throughout the water column as a whole were most positively correlated to depth and salinity and negatively correlated to dissolved oxygen and light. In contrast, nitrite oxidation rates throughout the water column were negatively correlated with light and pH. Multivariate regression analysis revealed that while both surface (20 m) ammonium oxidation rates were most strongly predicted by depth and light, surface rates were also regulated by salinity and deep rates by temperature. Surface (20 m) nitrite oxidation rates. These results support the growing body of evidence that ammonium oxidation and nitrite oxidation are not always coupled, should be measured separately, and are influenced by different environmental conditions.

  5. Root ABA Accumulation Enhances Rice Seedling Drought Tolerance under Ammonium Supply: Interaction with Aquaporins

    Science.gov (United States)

    Ding, Lei; Li, Yingrui; Wang, Ying; Gao, Limin; Wang, Min; Chaumont, François; Shen, Qirong; Guo, Shiwei

    2016-01-01

    In previous studies, we demonstrated that ammonium nutrition enhances the drought tolerance of rice seedlings compared to nitrate nutrition and contributes to a higher root water uptake ability. It remains unclear why rice seedlings maintain a higher water uptake ability when supplied with ammonium under drought stress. Here, we focused on the effects of nitrogen form and drought stress on root abscisic acid (ABA) concentration and aquaporin expression using hydroponics experiments and stimulating drought stress with 10% PEG6000. Drought stress decreased the leaf photosynthetic rate and stomatal conductivity and increased the leaf temperature of plants supplied with either ammonium or nitrate, but especially under nitrate supply. After 4 h of PEG treatment, the root protoplast water permeability and the expression of root PIP and TIP genes decreased in plants supplied with ammonium or nitrate. After 24 h of PEG treatment, the root hydraulic conductivity, the protoplast water permeability, and the expression of some aquaporin genes increased in plants supplied with ammonium compared to those under non-PEG treatment. Root ABA accumulation was induced by 24 h of PEG treatment, especially in plants supplied with ammonium. The addition of exogenous ABA decreased the expression of PIP and TIP genes under non-PEG treatment but increased the expression of some of them under PEG treatment. We concluded that drought stress induced a down-regulation of aquaporin expression, which appeared earlier than did root ABA accumulation. With continued drought stress, aquaporin expression and activity increased due to root ABA accumulation in plants supplied with ammonium.

  6. The ammonium content in the Malayer igneous and metamorphic rocks (Sanandaj-Sirjan Zone, Western Iran)

    Science.gov (United States)

    Ahadnejad, Vahid; Hirt, Ann Marie; Valizadeh, Mohammad-Vali; Bokani, Saeed Jabbari

    2011-04-01

    The ammonium (NH4+) contents of the Malayer area (Western Iran) have been determined by using the colorimetric method on 26 samples from igneous and metamorphic rocks. This is the first analysis of the ammonium contents of Iranian metamorphic and igneous rocks. The average ammonium content of metamorphic rocks decreases from low-grade to high-grade metamorphic rocks (in ppm): slate 580, phyllite 515, andalusite schist 242. In the case of igneous rocks, it decreases from felsic to mafic igneous types (in ppm): granites 39, monzonite 20, diorite 17, gabbro 10. Altered granitic rocks show enrichment in NH4+ (mean 61 ppm). The high concentration of ammonium in Malayer granites may indicate metasedimentary rocks as protoliths rather than meta-igneous rocks. These granitic rocks (S-types) have high K-bearing rock-forming minerals such as biotite, muscovite and K-feldspar which their potassium could substitute with ammonium. In addition, the high ammonium content of metasediments is probably due to inheritance of nitrogen from organic matter in the original sediments. The hydrothermally altered samples of granitic rocks show highly enrichment of ammonium suggesting external sources which intruded additional content by either interaction with metasedimentary country rocks or meteoritic solutions.

  7. Antibacterial Activity of Dental Cements Containing Quaternary Ammonium Polyethylenimine Nanoparticles

    Directory of Open Access Journals (Sweden)

    Nurit Beyth

    2012-01-01

    Full Text Available Glass ionomer cements (GICs are commonly used for cementing full cast crown restorations. Regrettably, although the dental cements fill the gap between the tooth and the crown, bacterial microleakage may occur, resulting in secondary caries. As microleakage cannot be completely prevented, GICs possessing antibacterial properties are in demand. In the present study the antibacterial activity of insoluble, cross-linked quaternary ammonium polyethylenimine (QPEI nanoparticles incorporated at 1% w/w in two clinically available GICs were studied. The antibacterial activity was tested against Streptococcus mutans and Lactobacillus casei using the direct contact test (DCT and the agar diffusion test (ADT. Using the direct contact test, antibacterial activity (<0.05 was found in both tested GICs with incorporated QPEI nanoparticles, the effect lasting for at least one month. However, the ADT showed no inhibition halo in the test bacteria, indicating that the antimicrobial nanoparticles do not diffuse into the agar. The results show that the incorporation of QPEI nanoparticles in glass ionomer cements has a long-lasting antibacterial effect against Streptococcus mutans and Lactobacillus casei. Changing the antibacterial properties of glass ionomer cements by incorporating QPEI antibacterial nanoparticles may prolong the clinical performance of dental crowns.

  8. Alanine synthesis from glyceraldehyde and ammonium ion in aqueous solution

    Science.gov (United States)

    Weber, A. L.

    1985-01-01

    The formation of alanine (ala) form C(14)-glyceraldehyde and ammonium phosphate in the presence or absence of a thiol is reported. At ambient temperature, ala synthesis was six times more rapid in the presence of 3-mercaptopropionic acid than in its absence (0.6 and 0.1 percent, respectively, after 60 days). Similarly, the presence of another thiol, N-acetylcysteinate, increased the production of ala, as well as of lactate. The reaction pathway of thiol-catalyzed synthesis of ala, with the lactic acid formed in a bypath, is suggested. In this, dehydration of glyceraldehyde is followed by the formation of hemithioacetal. In the presence of ammonia, an imine is formed, which eventually yields ala. This pathway is consistent with the observation that the rate ratio of ala/lactate remains constant throughout the process. The fact that the reaction takes place under anaerobic conditions in the presence of H2O and with the low concentrations of simple substrates and catalysts makes it an attractive model prebiotic reaction in the process of molecular evolution.

  9. Evaluation of a cesium adsorbent grafted with ammonium 12-molybdophosphate

    Science.gov (United States)

    Shibata, Takuya; Seko, Noriaki; Amada, Haruyo; Kasai, Noboru; Saiki, Seiichi; Hoshina, Hiroyuki; Ueki, Yuji

    2016-02-01

    A fibrous cesium (Cs) adsorbent was developed using radiation-induced graft polymerization with a cross-linked structure containing a highly stable adsorption ligand. The ligand, ammonium 12-molybdophosphate (AMP), was successfully introduced onto the fibrous polyethylene trunk material. The resulting Cs adsorbent contained 36% nonwoven fabric polyethylene (NFPE), 1% AMP, 2% triallyl isocyanurate (TAIC) and 61% glycidyl methacrylate (GMA). The adsorbent's Cs adsorption capacity was evaluated using batch and column tests. It was determined that the adsorbent could be used in a wide pH range. The amount of desorbed molybdenum, which can be used as an estimate for AMP stability on the Cs adsorbent, was minimized at the standard drinking water pH range of 5.8-8.6. Based from the inspection on the adherence of these results to the requirements set forth by the Food Sanitation Act by a third party organization, it can be concluded that the developed Cs adsorbent can be safely utilized for drinking water.

  10. Evaluation of ammonium polyphosphate fertilizer as a carrier of zinc

    International Nuclear Information System (INIS)

    Ammonium polyphosphate (APP) and diammonium orthophosphate (DAP) were evaluated as carriers of zinc in an Ultisol and a Vertisol. Surface applications of 65Zn along with urea or orthophosphate or pyrophosphate or polyphosphate to the two soils indicated very little movement of the radionuclide below 2 cm from surface in both soils on leaching with rain water. Greenhouse experiments with maize and red kidney beans grown in sequence in the two soils fertilized with APP and DAP both blended with 65Zn (as ZnSO4.7H2O) indicated that while the Zn fertilizer use efficiency of Zn-APP blend was significantly higher than that of Zn-DAP blend for maize, their residual value was equal for the succeeding bean crop. Experiments with maize-greengram sequence indicated superiority of Zn-APP blend only in Vertisol, while in Ultisol both the blends were equally effective. A field experiments with flooded rice indicated increased grain yield with application of Zn at 22 kg Zn ha-1. Neither P nor Zn application had any significant effect on straw yield. Grain and straw Zn concentrations increased significantly by the applications of both P and Zn. At zero or low levels of applied Zn, APP was significantly superior to DAP as a P source; while at higher dose of Zn, no significant difference was noted between the two P sources. (author). 18 refs, 5 tabs

  11. Rubidium, cesium and potassium sorption with magnesium-ammonium phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Leont' eva, G.V.; Tomchuk, T.K.

    1986-01-01

    The possibility for using magnesium-ammonium phosphate as a sorbent to separate Cs/sup +/, Rb/sup +/ and K/sup +/ ions is estimated. The sorbent composition is close to NH/sub 4/MgPO/sub 4/x6H/sub 2/O. Sorption isotherms have been removed under static conditions at 293+-2 K separately for Cs/sup +/, Rb/sup +/ and K/sup +/ ions. Determination of the separation coefficients of these Cs/sup +/-Rb/sup +/ and Rb/sup +/-K/sup +/ ion pairs (the ratio of the ions separated in the initial solution varies from 1:1 to 1:10) during their sorption by NH/sub 4/MgPO/sub 4/x6H/sub 2/O phosphate gave the following estimation of the values measured: P/sub Cs-Rb/=(30-156) and P/sub Rb-K/=(7-15). Taking into account high values of the separation coefficients and good reversibility of the ion exchange process NH/sub 4//sup +/reversibleMe/sup +/(Me/sup +/=Cs/sup +/, Rb/sup +/, K/sup +/) by phosphate and with the struvite structure, it is possible to recommend this sorbent for practical application.

  12. Photoluminescence from silicon nanoparticles embedded in ammonium silicon hexafluoride

    Energy Technology Data Exchange (ETDEWEB)

    Kalem, Seref [UEKAE, National Research Institute of Electronics and Cryptology, Gebze 41470 Kocaeli (Turkey); Werner, Peter; Becker, Michael; Zakharov, Nikolai [Department of Experimental Physics, Max-Planck-Institute, Halle(Saale) (Germany); Talalaev, Vadim [ZIK ' SiLi-nano' , Martin-Luther-Universitaet (Halle), Karl-Freiherr-von-Fritsch-Strasse 3 D-06120 Halle (Germany); Arthursson, Oerjan, E-mail: s.kalem@uekae.tubitak.gov.tr [Microtechnology and Nanosciences Department, Chalmers University of Technology, Goeteborg (Sweden)

    2010-10-29

    Silicon (Si) nanoparticles (NPs) were synthesized by transforming a Si wafer surface to ammonium silicon hexafluoride (ASH) or (NH{sub 4}){sub 2}SiF{sub 6} under acid vapor treatment. Si-NPs which were found to be embedded within the polycrystalline (ASH) layer exhibit a strong green-orange photoluminescence (PL). Differential PL measurements revealed a major double component spectrum consisting of a broad band associated with the ASH-Si wafer interfacial porous oxide layer and a high energy band attributable to Si-NPs embedded in the ASH. The origin of the latter emission can be explained in terms of quantum/spatial confinement effects probably mediated by oxygen related defects in or around Si-NPs. Although Si-NPs are derived from the interface they are much smaller in size than those embedded within the interfacial porous oxide layer (SiO{sub x}, x > 1.5). Transmission electron microscopy (TEM) combined with Raman scattering and Fourier transformed infrared (FTIR) analysis confirmed the presence of Si-NP and Si-O bondings pointing to the role of oxygen related defects in a porous/amorphous structure. The presence of oxygen of up to 4.5 at.% in the (NH{sub 4}){sub 2}SiF{sub 6} layer was confirmed by energy dispersive spectroscopy (EDS) analysis.

  13. Synthesis, Characterization and Thermal Decomposition Mechanism of Cetyltrimethyl Ammonium Tetrathiotungstate

    Institute of Scientific and Technical Information of China (English)

    Gaojun An; Yunqi Liu; Yongming Chai; Hongyan Shang; Chenguang Liu

    2006-01-01

    The synthesis, characterization and thermal decomposition mechanism of cetyltrimethyl ammonium tetrathiotungstate (CTriMATT) were studied herein. The as-synthesized CTriMATT was characterized by Elemental analysis, X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Ultraviolet visible (UV-Vis) spectra. The results showed that the as-synthesized CTriMATT had high purity and good crystallinity. The introduction of alkyl groups induced a shift of the stretching vibration band of W-S bond to lower wavenumber, while it had no influence on the position of WS2-4. Thermogravimetric analysis (TG), differential thermal analysis (DTA) and in situ XRD characterizations revealed that CTriMATT began to decompose at 423 K in nitrogen and was converted to WS2 eventually. In addition,the decomposition product of CTriMATT at 673 K in nitrogen was characterized by N2 adsorption (BET)and scanning electron microscopy (SEM). The results demonstrated that WS2 with higher specific surface area, and pore volume could be obtained from the thermal decomposition of CTriMATT in nitrogen.

  14. Organomontmorillonites Modified with 2-Methacryloyloxy Ethyl Alkyl Dimethyl Ammonium Bromide

    Institute of Scientific and Technical Information of China (English)

    WANG Jian-quan; WU Wen-hui

    2007-01-01

    Organomontmorillonites (organo-MMT) were synthesized by means of montmorillonites (MMT) modified with a series of 2-methacryloyloxy ethyl alkyl dimethyl ammonium bromide (MAAB) having different alkyl chain lengths as cationic surfactants through a cationic exchanging reaction, and were characterized by FTIR, TG, elemental analysis, and XRD. The microenvironment of the organic interlayer such as the orientation and arrangement of the alkyl chains of MAAB, as well as the properties of nanocomposite hydrogels, were also investigated. The amount of organic components absorbed on interlayer and the basal spacing of organo-MMT both increase with the increasing of alkyl length of MAAB. When carbon number of alkyl chain is in the region of 8 to 14, the alkyl chains between layers would adopt a disordered gauche conformation; while the carbon number is 16, an ordered all-trans conformation with a vertical orientation would be found together with the disordered gauche conformation according to the results of XRD and FTIR. Due to the difference of microenvironment of organic interlayer, the Young's moduli of the nanocomposite hydrogels increased as the alkyl chains of MAAB became longer.

  15. Interaction of ochratoxin A with quaternary ammonium beta-cyclodextrin.

    Science.gov (United States)

    Poór, Miklós; Kunsági-Máté, Sándor; Szente, Lajos; Matisz, Gergely; Secenji, Györgyi; Czibulya, Zsuzsanna; Kőszegi, Tamás

    2015-04-01

    Ochratoxin A (OTA) is a widely spread nephrotoxic food contaminant mycotoxin. Unfortunately, attenuation or prevention of the toxic effects of OTA is still an unresolved problem. Molecular inclusion of OTA by cyclodextrins (CDs) results in complexes with low stability. In the human organism, OTA exists mostly in the dianionic state (OTA(2-)). Therefore, our major goal was to develop a chemically modified cyclodextrin which gives a more stable complex with OTA than the previously published derivatives and which shows stronger preference towards OTA(2-). In our fluorescence spectroscopic study we demonstrate that quaternary ammonium beta-cyclodextrin (QABCD) fulfils both of these requirements. The calculated stability constant of the QABCD-OTA(2-) complex was 28,840 M(-1) (about 200-fold higher than that of the β-CD-OTA(2-) complex). We hypothesize, that QABCD may be a suitable tool for the decontamination of different OTA-contaminated drinks; furthermore, for alleviation of the toxic effects of OTA, such complex formation may reduce its absorption from the intestine.

  16. Thermochemical Properties and Decomposition Kinetics of Ammonium Magnesium Phosphate Monohydrate

    Institute of Scientific and Technical Information of China (English)

    WU,Jian; YUAN,Ai-Qun; HUANG,Zai-Yin; TONG,Zhang-Fa; CHEN,Jie; LIANG,Rong-Lan

    2007-01-01

    Ammonium magnesium phosphate monohydrate NH4MgPO4·H2O was prepared via solid state reaction at room temperature and characterized by XRD, FT-IR and SEM. Thermochemical study was performed by an isoperibol solution calorimeter, non-isothermal measurement was used in a multivariate non-linear regression analysis to determine the kinetic reaction parameters. The results show that the molar enthalpy of reaction above is (28.795±0.182) kJ/mol (298.15 K), and the standard molar enthalpy of formation of the title complex is (-2185.43±13.80)kJ/mol (298.15 K). Kinetics analysis shows that the second decomposition of NH4MgPO4·H2O acts as a double-step reaction: an nth-order reaction (Fn) with n=4.28, E1=147.35 kJ/mol, A1=3.63×1013 s-1 is followed by a second-order reaction (F2) with E2=212.71 kJ/mol, A2= 1.82×1018 s-1.

  17. Interaction of ochratoxin A with quaternary ammonium beta-cyclodextrin.

    Science.gov (United States)

    Poór, Miklós; Kunsági-Máté, Sándor; Szente, Lajos; Matisz, Gergely; Secenji, Györgyi; Czibulya, Zsuzsanna; Kőszegi, Tamás

    2015-04-01

    Ochratoxin A (OTA) is a widely spread nephrotoxic food contaminant mycotoxin. Unfortunately, attenuation or prevention of the toxic effects of OTA is still an unresolved problem. Molecular inclusion of OTA by cyclodextrins (CDs) results in complexes with low stability. In the human organism, OTA exists mostly in the dianionic state (OTA(2-)). Therefore, our major goal was to develop a chemically modified cyclodextrin which gives a more stable complex with OTA than the previously published derivatives and which shows stronger preference towards OTA(2-). In our fluorescence spectroscopic study we demonstrate that quaternary ammonium beta-cyclodextrin (QABCD) fulfils both of these requirements. The calculated stability constant of the QABCD-OTA(2-) complex was 28,840 M(-1) (about 200-fold higher than that of the β-CD-OTA(2-) complex). We hypothesize, that QABCD may be a suitable tool for the decontamination of different OTA-contaminated drinks; furthermore, for alleviation of the toxic effects of OTA, such complex formation may reduce its absorption from the intestine. PMID:25442535

  18. Proton transfer in gas-phase ammonium dinitramide clusters

    Science.gov (United States)

    Alavi, Saman; Thompson, Donald L.

    2003-02-01

    Proton transfer in gaseous ammonium dinitramide (ADN) clusters up to (ADN)2 is studied by using density-functional theory. Proton transfer between the hydrogen dinitramide and ammonia units does not occur in the ADN monomer, rather the ammonia-hydrogen dinitramide complex is stabilized by strong hydrogen bonding. However, proton transfer between hydrogen dinitramide and ammonia is observed in the ADN dimer [NH3HN(NO2)2]2, ADN solvated with a single ammonia molecule [NH3NH(NO2)2]NH3, and ADN solvated with a hydrogen dinitramide molecule [NH3HN(NO2)2]HN(NO2)2. Structural changes in the complexes relative to the free molecules and the binding energies of the clusters are given. Using population analysis, the total electrostatic interaction energy in each cluster is calculated. The electrostatic energy is a measure that distinguishes between the ionic or hydrogen-bonded nature of the clusters. Some implications of proton transfer in ADN clusters on the decomposition mechanism of ADN are discussed.

  19. Atmospheric transport and wet deposition of ammonium in North Carolina

    Science.gov (United States)

    Walker, John T.; Aneja, Viney P.; Dickey, David A.

    Wet deposition and transport analysis has been performed for ammonium (NH 4+) in North Carolina, USA. Multiple regression analysis is employed to model the temporal trend and seasonality in monthly volume-weighted mean NH 4+ concentrations in precipitation from 1983 to 1996 at six National Atmospheric Deposition Program/National Trends Network (NADP/NTN) sites. A significant ( ppopulated network of swine and poultry operations. This trend is positively correlated with increasing ammonia (NH 3) emissions related to the vigorous growth of North Carolina's swine population since 1990, particularly in the state's Coastal Plain region. A source-receptor regression model, which utilizes weekly NH 4+ concentrations in precipitation in conjunction with boundary layer air mass back trajectories, is developed to statistically test for the influence of a particular NH 3 source region on NH 4+ concentrations at surrounding NADP/NTN sites for the years 1995-1996. NH 3 emissions from this source region, primarily evolving from swine and poultry operations, are found to increase NH 4+ concentration in precipitation at sites up to ≈80 km away. At the Scotland County (NC36) and Wake County (NC41) sites, mean NH 4+ concentrations show increases of at least 44% for weeks during which 25% or more back trajectories are influenced by this source region.

  20. Effects of High Ammonium Concentration on Growth and Nutrient Uptake of Lettuce Plants with Solution Culture

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A nutrition solution experiment was conducted over two months to investigate the response of vegetable crops to high concentrations of ammonium, using lettuce (Lactuca sativa L. cv. Angustana Irish) as a test crop. Ammonium concentrations were designed in 5 levels, ranging from 12 mmol N L-1 to 22 mmol N L-1 and local tap water was used as water source. At the first culture stage (0-9 days), lettuce plants maintained normal growth while the lettuce roots were increasingly impaired. During the subsequent three stages the root structure was greatly damaged, and roots became brown or black through continuous supply of high concentration of ammonium. However, there was no obvious reduction of the aboveground biomass of the plants in the high ammonium treatments compared to those supplied with nitrate alone. In contrast to results obtained in another experiment from us with distilled water, the detrimental effect of high ammonium concentration on lettuce growth was greatly alleviated. Based on the results, it was postulated that the small amount of nitrate and the higher amount of bicarbonate existed in the tap water might mitigate the adverse effects of high ammonium N. The higher bicarbonate content in water and soil has usually been regarded as a major constraint factor limiting plant growth in calcareous soil areas. However, the reaction of bicarbonate to ammonium might produce positively interactive effect on reduction of both damages. The lettuce plants grown in ammonium solutions took up less P, K, Fe, Mn and Cu and more Ca than those grown in the nitrate nutrient solution. In conclusion, the results indicated that the N form imposed an obvious influence on absorption of cations and anions. Supplying ammonium-N stimulated transport of Ca, Mg and Mn to shoots of lettuce.

  1. Natural attenuation potential of tricholoroethene in wetland plant roots: role of native ammonium-oxidizing microorganisms.

    Science.gov (United States)

    Qin, Ke; Struckhoff, Garrett C; Agrawal, Abinash; Shelley, Michael L; Dong, Hailiang

    2015-01-01

    Bench-scale microcosms with wetland plant roots were investigated to characterize the microbial contributions to contaminant degradation of trichloroethene (TCE) with ammonium. The batch system microcosms consisted of a known mass of wetland plant roots in aerobic growth media where the roots provided both an inoculum of root-associated ammonium-oxidizing microorganisms and a microbial habitat. Aqueous growth media, ammonium, and TCE were replaced weekly in batch microcosms while retaining roots and root-associated biomass. Molecular biology results indicated that ammonium-oxidizing bacteria (AOB) were enriched from wetland plant roots while analysis of contaminant and oxygen concentrations showed that those microorganisms can degrade TCE by aerobic cometabolism. Cometabolism of TCE, at 29 and 46 μg L(-1), was sustainable over the course of 9 weeks, with 20-30 mg L(-1) ammonium-N. However, at 69 μg L(-1) of TCE, ammonium oxidation and TCE cometabolism were completely deactivated in two weeks. This indicated that between 46 and 69 μg L(-1) TCE with 30 mg L(-1) ammonium-N there is a threshold [TCE] below which sustainable cometabolism can be maintained with ammonium as the primary substrate. However, cometabolism-induced microbial deactivation of ammonium oxidation and TCE degradation at 69 μg L(-1) TCE did not result in a lower abundance of the amoA gene in the microcosms, suggesting that the capacity to recover from TCE inhibition was still intact, given time and removal of stress. Our study indicates that microorganisms associated with wetland plant roots can assist in the natural attenuation of TCE in contaminated aquatic environments, such as urban or treatment wetlands, and wetlands impacted by industrial solvents.

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

    Science.gov (United States)

    Torvinen, Mika; Kalenius, Elina; Sansone, Francesco; Casnati, Alessandro; Jänis, Janne

    2012-02-01

    The noncovalent complexation of monoamine neurotransmitters and related ammonium and quaternary ammonium ions by a conformationally flexible tetramethoxy glucosylcalix[4]arene was studied by electrospray ionization Fourier transform ion cyclotron resonance (ESI-FTICR) mass spectrometry. The glucosylcalixarene exhibited highest binding affinity towards serotonin, norepinephrine, epinephrine, and dopamine. Structural properties of the guests, such as the number, location, and type of hydrogen bonding groups, length of the alkyl spacer between the ammonium head-group and the aromatic ring structure, and the degree of nitrogen substitution affected the complexation. Competition experiments and guest-exchange reactions indicated that the hydroxyl groups of guests participate in intermolecular hydrogen bonding with the glucocalixarene.

  3. Effect of ammonium nutrition on the nitrate utilization, nitrate reductase actvity and growth of Spirodela polyrrhiza

    Directory of Open Access Journals (Sweden)

    Ewa Tatkowska

    2014-02-01

    Full Text Available The influence of NH4+ ions on nitrate assimilation and growth of sterile Spirodela polyrrhiza cultures was investigated. S. polyrrhiza utilises both the nitrate and the ammonium form of nitrogen, it prefers, however, NH4+. Ammonium ions present in the nitrate medium inhibit the activity of nitrate reductase (NR, but they do not affect enzyme 'induction and only slightly reduce N03- uptake. These results sugest that the inhibitory effect of NH4+ on the NR activity is the main cause of the decrease in N03- assimilation by S. polyrrhiza cultures growing in nitrate-ammonium medium.

  4. an investigation of the ammonium poly uranate precipitation via uranyl nitrate solution

    International Nuclear Information System (INIS)

    a series of experiments were made concerning the interaction of uranyl nitrate with ammonium hydroxide solution, with the aim of preparing ammonium poly uranate (APU) as an intermediate product during nuclear reactors fuel fabrication. the particle size and final product characteristics of the uranium oxide depend greatly on the ways of preparation of the APU , in the present work, the kinetics of deposition and the composition of the formed products upon adding increasing amounts of ammonium hydroxide to uranyl nitrate solution have been followed in a trial to understand the prevailing mechanisms

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    Removing ammonium from drinking water is important for maintaining biological stability in distribution systems. This is especially important in regions that do not use disinfectants in the treatment process or keep a disinfectant residual in the distribution system. Problems with nitrification c...... the total number of ammonium oxidizing bacteria in the column. © 2013 American Water Works Association AWWA WQTC Conference Proceedings All Rights Reserved.......Removing ammonium from drinking water is important for maintaining biological stability in distribution systems. This is especially important in regions that do not use disinfectants in the treatment process or keep a disinfectant residual in the distribution system. Problems with nitrification can...

  6. Ammonium first: natural mosses prefer atmospheric ammonium but vary utilization of dissolved organic nitrogen depending on habitat and nitrogen deposition.

    Science.gov (United States)

    Liu, Xue-Yan; Koba, Keisuke; Makabe, Akiko; Li, Xiao-Dong; Yoh, Muneoki; Liu, Cong-Qiang

    2013-07-01

    Mosses, among all types of terrestrial vegetation, are excellent scavengers of anthropogenic nitrogen (N), but their utilization of dissolved organic N (DON) and their reliance on atmospheric N remain uncharacterized in natural environments, which obscures their roles in N cycles. Natural (15) N abundance of N sources (nitrate (NO(3)(-)), ammonium (NH(4)(+)) and DON in deposition and soil) for epilithic and terricolous mosses was analyzed at sites with different N depositions at Guiyang, China. Moss NO(3)(-) assimilation was inhibited substantially by the high supply of NH(4)(+) and DON. Therefore, contributions of NH(4)(+) and DON to moss N were partitioned using isotopic mass-balance methods. The N contributions averaged 56% and 46% from atmospheric NH(4)(+), and 44% and 17% from atmospheric DON in epilithic and terricolous mosses, respectively. In terricolous mosses, soil NH(4)(+) and soil DON accounted for 16% and 21% of bulk N, which are higher than current estimations obtained using (15) N-labeling methods. Moreover, anthropogenic NH(4)(+) deposition suppressed utilization of DON and soil N because of the preference of moss for NH(4)(+) under elevated NH(4)(+) deposition. These results underscore the dominance of, and preference for, atmospheric NH(4)(+) in moss N utilization, and highlight the importance of considering DON and soil N sources when estimating moss N sequestration and the impacts of N deposition on mosses. PMID:23692546

  7. Ammonium nitrate evaporation and nitric acid condensation in DMT CCN counters

    Science.gov (United States)

    Romakkaniemi, S.; Jaatinen, A.; Laaksonen, A.; Nenes, A.; Raatikainen, T.

    2014-05-01

    The effect of inorganic semivolatile aerosol compounds on the cloud condensation nucleus (CCN) activity of aerosol particles was studied by using a computational model for a DMT-CCN counter, a cloud parcel model for condensation kinetics and experiments to quantify the modelled results. Concentrations of water vapour and semivolatiles as well as aerosol trajectories in the CCN column were calculated by a computational fluid dynamics model. These trajectories and vapour concentrations were then used as an input for the cloud parcel model to simulate mass transfer kinetics of water and semivolatiles between aerosol particles and the gas phase. Two different questions were studied: (1) how big a fraction of semivolatiles is evaporated from particles after entering but before particle activation in the DMT-CCN counter? (2) How much can the CCN activity be increased due to condensation of semivolatiles prior to the maximum water supersaturation in the case of high semivolatile concentration in the gas phase? Both experimental and modelling results show that the evaporation of ammonia and nitric acid from ammonium nitrate particles causes a 10 to 15 nm decrease to the critical particle size in supersaturations between 0.1% and 0.7%. On the other hand, the modelling results also show that condensation of nitric acid or similar vapour can increase the CCN activity of nonvolatile aerosol particles, but a very high gas phase concentration (as compared to typical ambient conditions) would be needed. Overall, it is more likely that the CCN activity of semivolatile aerosol is underestimated than overestimated in the measurements conducted in ambient conditions.

  8. Identification and Characterization of Visible Absorption Components in Aqueous Methylglyoxal-Ammonium Sulfate Mixtures

    Science.gov (United States)

    McGivern, W. S.; Allison, T. C.; Radney, J. G.; Zangmeister, C. D.

    2014-12-01

    The aqueous reaction of methylglyoxal (MG) with ammonium sulfate has been suggested as a source of atmospheric ``brown carbon.'' We have utilized high-performance liquid chromatography coupled to ultraviolet-visible spectroscopy and tandem mass spectrometry to study the products of this reaction at high concentrations. The overall product spectrum shows a large number of distinct components; however, the visible absorption from this mixture is derived a very small number of components. The largest contributor is an imine-substituted (C=N-H) product of aldol condensation/facile dehydration reaction between the parent MG and a hydrated product of the MG + ammonia reaction. The asymmetric nature of this compound relative to the aldol condensation of two MG results in a sufficiently large redshift of the UV absorption spectrum that absorption of visible radiation can occur in the long-wavelength tail. The simplicity of the imine products is a result of a strong bias toward ketimine products due to the extensive hydration of the aldehydic moiety in the parent in aqueous solution. In addition, a strong pH dependence of the absorption cross section was observed with significantly greater absorption under more basic conditions. We have performed time-dependent density functional theory calculations to evaluate the absorption spectra of all of the possible condensation products and their respective ions, and the results are consistent with the experimental observations. We have also observed smaller concentrations of other condensation products of the imine-substituted parent species that do not contribute significantly to the visible absorption but have not been previously discussed.

  9. Nitrate and Ammonium Contribute to the Distinct Nitrogen Metabolism of Populus simonii during Moderate Salt Stress.

    Science.gov (United States)

    Meng, Sen; Su, Li; Li, Yiming; Wang, Yinjuan; Zhang, Chunxia; Zhao, Zhong

    2016-01-01

    Soil salinity is a major abiotic stressor affecting plant growth. Salinity affects nitrification and ammonification in the soil, however, limited information is available on the influence of different N sources on N metabolism during salt stress. To understand the N metabolism changes in response to different N sources during moderate salt stress, we investigated N uptake, assimilation and the transcript abundance of associated genes in Populus simonii seedlings treated with moderate salt stress (75mM NaCl) under hydroponic culture conditions with nitrate (NO3-) or ammonium (NH4+). Salt stress negatively affected plant growth in both NH4+-fed and NO3--fed plants. Both NH4+ uptake and the total N concentration were significantly increased in the roots of the NH4+-fed plants during salt stress. However, the NO3- uptake and nitrate reductase (NR) and nitrite reductase (NiR) activity primarily depended on the NO3- supply and was not influenced by salt stress. Salt stress decreased glutamine synthetase (GS) and glutamate synthase (GOGAT) activity in the roots and leaves. Most genes associated with NO3-uptake, reduction and N metabolism were down-regulated or remained unchanged; while two NH4+ transporter genes closely associated with NH4+ uptake (AMT1;2 and AMT1;6) were up-regulated in response to salt stress in the NH4+-fed plants. The accumulation of different amino acid compounds was observed in the NH4+- and NO3-- fed plants during salt treatment. The results suggested that N metabolism in P. simonii plants exposed to salt enhanced salt resistance in the plants that were fed with NO3- instead of NH4+ as the sole N source. PMID:26950941

  10. Photodeamination Reaction Mechanism in Aminomethyl p-Cresol Derivatives: Different Reactivity of Amines and Ammonium Salts.

    Science.gov (United States)

    Škalamera, Đani; Bohne, Cornelia; Landgraf, Stephan; Basarić, Nikola

    2015-11-01

    Derivatives of p-cresol 1-4 were synthesized, and their photochemical reactivity, acid-base, and photophysical properties were investigated. The photoreactivity of amines 1 and 3 is different from that for the corresponding ammonium salts 2 and 4. All compounds have low fluorescence quantum yields because the excited states undergo deamination reactions, and for all cresols the formation of quinone methides (QMs) was observed by laser flash photolysis. The reactivity observed is a consequence of the higher acidity of the S1 states of these p-cresols and the ability for excited-state intramolecular proton transfer (ESIPT) to occur in the case of 1 and 3, but not for salts 2 and 4. In aqueous solvent, deamination depends largely on the prototropic form of the molecule. The most efficient deamination takes place when monoamine is in the zwitterionic form (pH 9-11) or diamine is in the monocationic form (pH 7-9). QM1, QM3, and QM4 react with nucleophiles, and QM1 exhibits a shorter lifetime when formed from 1 (τ in CH3CN = 5 ms) than from 2 (τ in CH3CN = 200 ms) due to the reaction with eliminated dimethylamine, which acts as a nucleophile in the case of QM1. Bifunctional QM4 undergoes two types of reactions with nucleophiles, giving adducts or new QM species. The mechanistic diversity uncovered is of significance to biological systems, such as for the use of bifunctional QMs to achieve DNA cross-linking. PMID:26461794

  11. Occurrence of Anaerobic Ammonium Oxidation in the Yangtze Estuary

    Science.gov (United States)

    Hou, L.

    2013-12-01

    Over the past several decades, a large quantity of reactive nitrogen has been transported into the Yangtze estuarine and coastal water, due to intense human activities in the Yangtze River Basin. At present, it annually receives a high load of anthropogenic inorganic nitrogen (about 1.1 × 1011 mol N) from increased agricultural activities, fish farming, and domestic and industrial wastewater discharge in the Yangtze River Basin, consequently leading to severe eutrophication and frequent occurrences of harmful algal blooms in the estuary and adjacent coastal areas. Hence, the microbial nitrogen transformations are of major concern in the Yangtze Estuary. Anaerobic ammonium oxidation (anammox) has been reported to play a significant role in the removal of reactive nitrogen in aquatic ecosystems. In this study, the occurrences of anammox bacteria and associated activity in the Yangtze Estuary were evidenced with molecular and isotope-tracing techniques. It is observed that the anammox bacteria at the study area mainly consisted of Candidatus Scalindua, Brocadia, Kuenenia. Salinity was found to be a key environmental factor controlling distribution and diversity of the anammox bacterial community at the estuarine ecosystem. Also, temperature and organic carbon had significant influences on anammox bacterial biodiversity. Q-PCR assays of anammox bacteria indicated that their abundance had a range of 2.63 ×106 - 9.48 ×107 copies g-1 dry sediment, with high spatiotemporal heterogeneity. The potential anammox activities measured in the present work varied between 0.94 - 6.61nmol N g-1 dry sediment h-1, which were related to temperature, nitrite and anammox bacterial abundance. On the basis of the 15N tracing experiments, the anammox process was estimated to contribute 6.6 - 12.9 % to the total nitrogen loss whereas the remainder was attributed to denitrification.

  12. A strong isotope effect in the phase transition behaviour of ammonium hexachlorotellurate

    International Nuclear Information System (INIS)

    Heat capacity and neutron powder diffraction measurements have been performed on protonated and deuterated ammonium hexachlorotellurate. This powerful combination of techniques has provided a detailed picture of the novel phase transition behaviour in these materials. (orig.)

  13. Heterotrophic ammonium removal characteristics of an aerobic heterotrophic nitrifying-denitrifying bacterium, Providencia rettgeri YL

    Institute of Scientific and Technical Information of China (English)

    TAYLOR Shauna M; HE Yiliang; ZHAO Bin; HUANG Jue

    2009-01-01

    Bacterium Providencia rettgeri YL was found to exhibit an unusual ability to heterotrophically nitrify and aerobically denitrify various concentrations of ammonium (NH4+-N). In order to further analyze its removal ability, several experiments were conducted to identify the growth and ammonium removal response in different carbon to nitrogen (C/N) mass ratios, shaking speeds, temperatures, ammonium concentrations and to qualitatively verify the production of nitrogen gas using gas chromatography techniques. Results showed that under optimum conditions (C/N 10, 30℃, 120 r/min), YL can significantly remove low and high concentrations of ammonium within 12 to 48 h of growth. The nitrification products hydroxylamine (NH2OH), nitrite (NO2-) and nitrate (NO3-) as well as the denitrification product, nitrogen gas (N2), were detected under completely aerobic conditions.

  14. Properties of the Nafion membrane impregnated with hydroxyl ammonium based ionic liquids

    Science.gov (United States)

    Garaev, Valeriy; Kleperis, Janis; Pavlovica, Sanita; Vaivars, Guntars

    2012-08-01

    In this work, the Nafion 112 membrane impregnated with nine various hydroxyl ammonium based ionic liquids have been investigated. The used ionic liquids were combined from hydroxyl ammonium cations (2-hydroxyethylammonium/HEA, bis(2- hydroxyethyl)ammonium/BHEA, tris(2-hydroxyethyl)ammonium/THEA) and carboxylate anions (formate, acetate, lactate). The membranes are characterized by conductivity and thermal stability measurements. It was found, that almost all composites have 10 times higher ion conductivity than a pure Nafion 112 at 90 °C in ambient environment due to the higher thermal stability. The thermal stability of Nafion membrane was increased by all studied nine ionic liquids. In this work, only biodegradable ionic liquids were used for composite preparation.

  15. Antibacterial properties of poly(quaternary ammonium) modified gold and titanium dioxide nanoparticles.

    Science.gov (United States)

    Wan, Weijie; Yeow, John T W

    2012-06-01

    We report excellent antibacterial effect induced by amine-functionalized gold and titanium dioxide nanoparticles without external excitations. The idea originates from the excellent antibacterial property of quaternary ammonium salts. The effects of poly(quaternary ammonium) and polyacrylate sodium functional groups as nanoparticle surfactants are compared to show that poly(quaternary ammonium) functional groups are the main cause of the induced antibacterial effect. 99.999% of E. coli can be destructed in 10 minutes by simply mixing bacteria with nanoparticle dispersions. The effect of nanoparticle concentrations on the antibacterial property is evaluated. Time required to significantly suppress bacteria growth is studied. The result indicates that the excellent antibacterial property can be introduced to any nanomaterials by using poly(quaternary ammonium) functional groups as surfactants. The engineered nanoparticles can find enormous applications such as self-cleaning surfaces, waste water treatment, Lab-on-a-Chip devices and many more. PMID:22905506

  16. Plasmid DNA induces dodecyl triethyl ammonium bromide to aggregate into vesicle

    Institute of Scientific and Technical Information of China (English)

    Xiang Mei Ran; Xia Guo; Jia Tong Ding

    2012-01-01

    Single-chained cationic surfactant dodecyl triethyl ammonium bromide and plasmid DNA together can form vesicles once the concentration of plasmid DNA reaches a critical value (Ccvc).Bigger the size of plasmid DNA,higher the value of Ccvc.

  17. Determination of ammonium in a buddingtonite sample by ion-chromatography

    Science.gov (United States)

    Klock, P.R.; Lamothe, P.J.

    1986-01-01

    An ion-chromatographic method for the direct determination of ammonium, potassium, and sodium in geologic materials is described. Samples are decomposed with a mixture of hydrofluoric and hydrochloric acids in a sealed polycarbonate bottle heated in a microwave oven. The ion-chromatograph separates the cations and determines them by conductivity measurement. The ammonium concentrations thus determined have been verified by use of an ammonia-specific electrode. A total of 32 analyses of ammonium salts by both techniques showed an average error of -4%, with a relative standard deviation (RSD) of 6%. The ammonium concentrations found in a buddingtonite sample had an RSD of 2.2% and their mean agreed with that obtained by the Kjeldahl method. By use of the prescribed dilution of the sample, detection limits of 0.1% can be achieved for all three cations. ?? 1986.

  18. CdTe/ZnS quantum dots as fluorescent probes for ammonium determination.

    Science.gov (United States)

    Yi, Kui-Yu

    2016-06-01

    Novel CdTe/ZnS quantum dot (QD) probes based on the quenching effect were proposed for the simple, rapid, and specific determination of ammonium in aqueous solutions. The QDs were modified using 3-mercaptopropionic acid, and the fluorescence responses of the CdTe/ZnS QD probes to ammonium were detected through regularity quenching. The quenching levels of the CdTe/ZnS QDs and ammonium concentration showed a good linear relationship between 4.0 × 10(-6) and 5.0 × 10(-4) mol/L; the detection limit was 3.0 × 10(-7) mol/L. Ammonium contents in synthetic explosion soil samples were measured to determine the practical applications of the QD probes and a probable quenching mechanism was described. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26542194

  19. Anatase-brookite mixed phase nano TiO2 catalyzed homolytic decomposition of ammonium nitrate.

    Science.gov (United States)

    Vargeese, Anuj A; Muralidharan, Krishnamurthi

    2011-09-15

    Compared to the conventional ammonium perchlorate based solid rocket propellants, burning of ammonium nitrate (AN) based propellants produce environmentally innocuous combustion gases. Application of AN as propellant oxidizer is restricted due to low reactivity and low energetics besides its near room temperature polymorphic phase transition. In the present study, anatase-brookite mixed phase TiO(2) nanoparticles (~ 10 nm) are synthesized and used as catalyst to enhance the reactivity of the environmental friendly propellant oxidizer ammonium nitrate. The activation energy required for the decomposition reactions, computed by differential and non-linear integral isoconversional methods are used to establish the catalytic activity. Presumably, the removal of NH(3) and H(2)O, known inhibitors of ammonium nitrate decomposition reaction, due to the surface reactions on active surface of TiO(2) changes the decomposition pathway and thereby the reactivity.

  20. Treatment of ammonium-rich swine waste in modified porphyritic andesite fixed-bed anaerobic bioreactor.

    Science.gov (United States)

    Wang, Qinghong; Yang, Yingnan; Li, Dawei; Feng, Chuanping; Zhang, Zhenya

    2012-05-01

    In this study, a modified porphyritic andesite (WRS) was developed as ammonium adsorbent and bed material for the anaerobic digestion of ammonium-rich swine waste. The performance in bioreactors with modified WRS, natural WRS, calcium chloride and no additives was investigated. The bioreactor with modified WRS exhibited the best performance, with start-up time on the 7th day, methane yield of 359.71 ml/g-VS, and COD removal of 67.99% during all 44 days of the experiment at 35°C. The effective ammonium adsorption and essential ions dissociation for microorganisms by modified WRS, as well as the immobilization of microbial on the surface of the modified WRS play a great role on the high efficiency anaerobic digestion of ammonium-rich swine waste. PMID:22366608

  1. Evaluation of chitosan quaternary ammonium salt-modified resin denture base material.

    Science.gov (United States)

    Song, Rong; Zhong, Zhaohua; Lin, Lexun

    2016-04-01

    Chitosan quaternary ammonium salt displays good antioxidant and antibacterial characteristics and it shows appreciable solubility in water. When added to the traditional denture material to form a resin base, it could promote good oral health by improving the oral environment. In this study, chitosan quaternary ammonium salt was added to the denture material following two different methods. After three months of immersion in artificial saliva, the specimens were tested for tensile strength and were scanned by electron microscope. The murine fibroblast cytotoxicity and antibacterial properties were also tested. The result showed no significant differences in the tensile strength and in the proliferation of murine L929 fibroblast cells. The two structures of chitosan quaternary ammonium salt-modified denture material had different degrees of corrosion resistance and antimicrobial properties. These results indicate that chitosan quaternary ammonium salt-modified resin denture base material has the potential to become a new generation oral denture composite material.

  2. The anomalous solid state decomposition of ammonium dinitramide: a matter of surface polarization.

    Science.gov (United States)

    Rahm, Martin; Brinck, Tore

    2009-05-28

    Polarized dinitramide anions on the surface of solid ammonium dinitramide (ADN) have a decomposition barrier that is reduced by 16 kcal mol(-1) and explain the anomalous solid state decomposition of ADN. PMID:19436902

  3. Interaction between Ammonium Toxicity and Green Tide Development Over Seagrass Meadows

    DEFF Research Database (Denmark)

    Marin, Francisco Moreno; Vergara, Juan J.; Pérez-Llorens, J. Lucas;

    2016-01-01

    Eutrophication affects seagrasses negatively by increasing light attenuation through stimulation of biomass of fast-growing, bloom-forming algae and because high concentrations of ammonium in the water can be toxic to higher plants. We hypothesized nevertheless, that moderate amounts of nitrophilic...... macroalgae that coexists with seagrasses under eutrophic conditions, can alleviate the harmful effects of eutrophication on seagrasses by reducing ammonium concentrations in the seawater to non-toxic levels because such algae have a very large capacity to take up inorganic nutrients. We studied therefore how...... combinations of different ammonium concentrations (0, 25 and 50 μM) and different standing stocks of macroalgae (i.e. 0, 1 and 6 layers of Ulva sp.) affected survival, growth and net production of the seagrass Zostera noltei. In the absence of Ulva sp., increasing ammonium concentrations had a negative...

  4. Crystal structure of cyclo­hexyl­ammonium thio­cyanate

    OpenAIRE

    Abdulaziz A. Bagabas; Sultan B. Alhoshan; Hazem A. Ghabbour; C S Chidan Kumar; Fun, Hoong-Kun

    2015-01-01

    In the title salt, C6H11NH3 +·SCN−, the cyclo­hexyl­ammonium ring adopts a slightly distorted chair conformation. The ammonium group occupies an equatorial position to minimize 1,3 and 1,5 diaxial inter­actions. In the crystal, the components are linked by N—H⋯N and N—H⋯S hydrogen-bonding inter­actions, resulting in a three-dimensional network.

  5. Ammonium nitrogen removal from coking wastewater by chemical precipitation recycle technology.

    Science.gov (United States)

    Zhang, Tao; Ding, Lili; Ren, Hongqiang; Xiong, Xiang

    2009-12-01

    Ammonium nitrogen removal from wastewater has been of considerable concern for several decades. In the present research, we examined chemical precipitation recycle technology (CPRT) for ammonium nitrogen removal from coking wastewater. The pyrolysate resulting from magnesium ammonium phosphate (MAP) pyrogenation in sodium hydroxide (NaOH) solution was recycled for ammonium nitrogen removal from coking wastewater. The objective of this study was to investigate the conditions for MAP pyrogenation and to characterize of MAP pyrolysate for its feasibility in recycling. Furthermore, MAP pyrolysate was characterized by scanning electron microscope (FESEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR) as well as X-ray diffraction (XRD). The MAP pyrolysate could be produced at the optimal condition of a hydroxyl (OH(-)) to ammonium molar ratio of 2:1, a heating temperature of 110 degrees C, and a heating time of 3h. Surface characterization analysis indicated that the main component of the pyrolysate was amorphous magnesium sodium phosphate (MgNaPO(4)). The pyrolysate could be recycled as a magnesium and phosphate source at an optimum pH of 9.5. When the recycle times were increased, the ammonium nitrogen removal ratio gradually decreased if the pyrolysate was used without supplementation. When the recycle times were increased, the ammonium nitrogen removal efficiency was not decreased if the added pyrolysate was supplemented with MgCl(2).6H(2)O plus Na(2)HPO(4).12H(2)O during treatment. A high ammonium nitrogen removal ratio was obtained by using pre-formed MAP as seeding material. PMID:19850316

  6. Reduction of formaldehyde concentrations in the air and cadaveric tissues by ammonium carbonate

    OpenAIRE

    Kawamata, Seiichi; Kodera, Haruo

    2004-01-01

    The reduction of formaldehyde by ammonium carbonate was examined in cadavers and in vitro. Formaldehyde concentrations in the air (10 cm above human cadavers) and in various cadaveric tissues were measured with or without perfusion of ammonium carbonate solution into formaldehyde-fixed cadavers. Air samples were monitored using Kitagawa gas detector tubes. For measurement of formaldehyde in tissues, muscles and organs were cut into small pieces and tissue fluids were separated out by centrifu...

  7. Synthesis of Main-Chain Chiral Quaternary Ammonium Polymers for Asymmetric Catalysis Using Quaternization Polymerization

    Directory of Open Access Journals (Sweden)

    Md. Masud Parvez

    2012-06-01

    Full Text Available Main-chain chiral quaternary ammonium polymers were successfully synthesized by the quaternization polymerization of cinchonidine dimer with dihalides. The polymerization occurred smoothly under optimized conditions to give novel type of main-chain chiral quaternary ammonium polymers. The catalytic activity of the polymeric chiral organocatalysts was investigated on the asymmetric benzylation of N-(diphenylmethylideneglycine tert-butyl ester.

  8. The Basis of Ammonium Release in nifL Mutants of Azotobacter vinelandii

    OpenAIRE

    Brewin, Brett; Woodley, Paul; DRUMMOND, MARTIN

    1999-01-01

    In Azotobacter vinelandii, nitrogen fixation is regulated at the transcriptional level by an unusual two-component system encoded by nifLA. Certain mutations in nifL result in the bacterium releasing large quantities of ammonium into the medium, and earlier work suggested that this occurs by a mechanism that does not involve NifA, the activator of nif gene transcription. We have investigated a number of possible alternative mechanisms and find no evidence for their involvement in ammonium rel...

  9. Synthesis and applications of novel bis(ammonium) chiral ionic liquids derived from isomannide

    DEFF Research Database (Denmark)

    Kumar, Vineet; Olsen, Carl Erik; Schäffer, Susan J.;

    2007-01-01

    Carbohydrate-based novel bis(ammonium) chiral ionic liquids have been synthesized by following a straightforward protocol using isomannide as the substrate. Their applications in chiral discrimination and optical resolution of racemates have been established.......Carbohydrate-based novel bis(ammonium) chiral ionic liquids have been synthesized by following a straightforward protocol using isomannide as the substrate. Their applications in chiral discrimination and optical resolution of racemates have been established....

  10. Synthesis of imidazoline-based dissymmetric bis-quaternary ammonium gemini surfactant and its inhibition mechanism on Q235 steel in hydrochloric acid medium

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, J.; Gong, X.L.; Song, W.W.; Jiang, B.; Du, M. [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, Shandong Province (China)

    2012-07-15

    An imidazoline-based dissymmetric bis-quaternary ammonium gemini surfactant has been synthesized. Its surface active properties at equilibrium in water at 25 C were determined. The inhibitive effect of the compound on Q235 steel in 1 M hydrochloric solution was investigated by the weight-loss method, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) analysis, and quantum chemical calculations. The results indicate that the compound has high surface properties and the inhibition efficiency (IE) increases with the increase in inhibitor concentration, which attain the maximum value around the CMC value. The imidazoline-based dissymmetric bis-quaternary ammonium acts as a mixed type inhibitor mainly inhibiting the cathodic processes and does not change the mechanism of either hydrogen evolution reaction or mild steel dissolution. The best IE is obtained at the immersion time of 144 h. The adsorption of the studied inhibitor on Q235 steel can be fitted to a Langmuir isotherm and the adsorption process is a spontaneous chemical adsorption. Quantum chemistry calculation results show that the imidazoline ring and heteroatoms of N, O, are the active sites of the inhibitors. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Salting-out extraction of allicin from garlic (Allium sativum L.) based on ethanol/ammonium sulfate in laboratory and pilot scale.

    Science.gov (United States)

    Li, Fenfang; Li, Qiao; Wu, Shuanggen; Tan, Zhijian

    2017-02-15

    Salting-out extraction (SOE) based on lower molecular organic solvent and inorganic salt was considered as a good substitute for conventional polymers aqueous two-phase extraction (ATPE) used for the extraction of some bioactive compounds from natural plants resources. In this study, the ethanol/ammonium sulfate was screened as the optimal SOE system for the extraction and preliminary purification of allicin from garlic. Response surface methodology (RSM) was developed to optimize the major conditions. The maximum extraction efficiency of 94.17% was obtained at the optimized conditions for routine use: 23% (w/w) ethanol concentration and 24% (w/w) salt concentration, 31g/L loaded sample at 25°C with pH being not adjusted. The extraction efficiency had no obvious decrease after amplification of the extraction. This ethanol/ammonium sulfate SOE is much simpler, cheaper, and effective, which has the potentiality of scale-up production for the extraction and purification of other compounds from plant resources. PMID:27664612

  12. 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.

  13. Synthesis of uranium fluorides from uranium dioxide with ammonium bifluoride and ammonolysis of uranium fluorides to uranium nitrides

    Science.gov (United States)

    Yeamans, Charles Burnett

    This work presents the chemical conversion of uranium oxides to uranium fluorides, and their subsequent conversion to uranium nitrides. Uranium dioxide reacts with ammonium bifluoride at 20°C to form compound in the ammonium-uranium fluoride chemical system. This reaction occurs between solid uranium dioxide at the surface of the particles and ammonium fluoride vapor. A shrinking-sphere model demonstrated surface reaction kinetics, not mass transport by diffusion through the product layer, limit the reaction rate when the starting material consists of 100 mum uranium dioxide particles. Powder x-ray diffraction showed the reaction to be complete within 8 hours, with (NH4) 4UF8 the reaction product. High-resolution electron microcopy revealed the product is largely amorphous on a micrometer-scale, but contains well-formed crystal domains on the order of 10x10 nm. X-ray diffraction showed the reaction progresses though beta-NH4UF5, delta-(NH 4)2UF6, and gamma-(NH4)2UF6 intermediate phases before finally forming (NH4)4UF 8. Modeling the system as a series of first-order reaction suggested a fourth intermediate, possibly UF4, is likely to occur. The reaction of (NH4)4UF8 with ammonia gas at 800°C forms alpha-U2N3/UN2 solid solution products with a composition of UN1.83. The x-ray powder diffraction pattern of this product is the fcc pattern commonly referenced as that of UN2 and the lattice parameter was 0.53050 nm. Surface area increased by a factor of ten during ammonolysis, consistent with the action of a hydriding agent. The alpha-U2N 3/UN2 solid solution system formed contained 1 wt% UO 2 as an impurity. Upon subsequent heating to 1150°C for 4.5 hours under argon, the nitride sample formed UN with a UO2 impurity of 9 wt%. Based on the HRTEM images, oxidation in the UN product appears to be limited to within 20 nm of particle surfaces and grain boundaries.

  14. Floc flotation of jamesonite fines in aqueous suspensions induced by ammonium dibutyl dithiophosphate

    Institute of Scientific and Technical Information of China (English)

    张婷; 覃文庆

    2015-01-01

    The hydrophobic flocculation of jamesonite fines in aqueous suspensions induced by ammonium dibutyl dithiophosphate was investigated using laser particle size analysis, microscope analysis, electrophoretic light scattering and infrared spectroscopy. Single minerals of 4.607 µm for the 50% volumetric diameters were researched by varying several parameters, including pH, ammonium dibutyl dithiophosphate concentration, stirring strength and kerosene addition. It is found that the maximal floatability of jamesonite fines is induced by ammonium dibutyl dithiophosphate at pH 6, and the floc flotation increases with increasing ammonium dibutyl dithiophosphate concentration despite a simultaneous increase in the negativeζpotential of jamesonite, meaning that hydrophobic interaction between the particles increases much more strongly than electric double layer repulsion from the adsorption of ammonium dibutyl dithiophosphate. It is also found that the floc flotation is closely correlated with the size of flocs, which is strongly influenced by the stirring strength and enhanced by the addition of a small amount of kerosene. The results of FTIR spectra indicate that adsorption of ammonium dibutyl dithiophosphate onto jamesonite is chemical adsorption and the adsorption product is lead dibutyl dithiophosphate.

  15. The basis of ammonium release in nifL mutants of Azotobacter vinelandii.

    Science.gov (United States)

    Brewin, B; Woodley, P; Drummond, M

    1999-12-01

    In Azotobacter vinelandii, nitrogen fixation is regulated at the transcriptional level by an unusual two-component system encoded by nifLA. Certain mutations in nifL result in the bacterium releasing large quantities of ammonium into the medium, and earlier work suggested that this occurs by a mechanism that does not involve NifA, the activator of nif gene transcription. We have investigated a number of possible alternative mechanisms and find no evidence for their involvement in ammonium release. Enhancement of NifA-mediated transcription, on the other hand, by either elimination of nifL or overexpression of nifA, resulted in ammonium release, correlating with enhanced levels of nifH mRNA, raised levels of nitrogenase and acetylene-reducing activity, and increased concentrations of intracellular ammonium. Up to 35 mM ammonium can accumulate in the medium. Where measured, intracellular levels exceeded extracellular levels, indicating that rather than being actively transported, ammonium is lost from the cell passively, possibly by reversal of an NH(4)(+) uptake system. The data also indicate that in the wild type the bulk of NifA is inactivated by NifL during steady-state growth on dinitrogen. PMID:10572141

  16. Application of Neesler reagent in the ammonium quantification used in the fermentations of biotechnology products

    Directory of Open Access Journals (Sweden)

    Dinorah Torres-Idavoy

    2015-08-01

    Full Text Available The ammonium salts are used in fermentations to supplement the deficient amounts of nitrogen and stabilize the pH of the culture medium. The excess ammonium ion exerts a detrimental effect on the fermentation process inhibiting microbial growth. An analytical method based on Neesler reagent was developed for monitoring and controlling the concentration of ammonium during the fermentation process. The test was standardized, by means of the selection of measuring equipment, and the reaction time as well as comparing standards of ammonium salts. The method was characterized with the evaluation of the next parameters: Specificity, Linearity and Range, Quantification Limit, Accuracy and Precision. The method proved to be specific. Two linear curves were defined in the ranges of concentrations of ammonium chloride salt (2-20 μg/ml and ammonium sulfate salt (5-30 μg/ml. The limits of quantification were the lowest points of each one. The method proved to be accurate and precise. This assay was applied to samples of the yeast culture and bacteria of the genus Saccharomyces and E. coli respectively. A novel method in micro plate for quantification and analytical control of ammonia was developed. This method is used to control this fundamental chemical component in the fermentations, to optimize the culture medium. Thus, an appropriate expression of recombinant proteins and proper vaccine candidates for clinical use are achieved

  17. Improving the Sensitivity of Matrix-Assisted Ionization (MAI) Mass Spectrometry Using Ammonium Salts.

    Science.gov (United States)

    Chubatyi, Nicholas D; McEwen, Charles N

    2015-10-01

    In matrix-assisted ionization (MAI), analyte incorporated in a small molecule matrix is introduced into an aperture linking atmospheric pressure with the vacuum of a mass spectrometer. Gas-phase analyte ions are spontaneously produced without use of a laser or high voltage. Here we investigate analyte and background ion abundances upon addition of ammonium salts to various MAI matrix/analyte solutions. Regardless of the ammonium salt or matrix used, chemical background ions are suppressed and/or analyte ion abundance improved for basic small molecules, peptides, and proteins. Background ion abundances increase with increasing inlet temperature, but are suppressed with addition of any of a variety of ammonium salts without much effect on the total ion abundances of the analyte ions. However, at lower inlet temperature using the matrices 2-bromo-2-nitropropane-1,3-diol, 1,2-dicyanobenzene, and 3-nitrobenzonitrile (3-NBN), analyte ion abundance increases and any chemical background decreases upon addition of ammonium salt. The improvement in sensitivity using 3-NBN with ammonium salt allows full acquisition mass spectra consuming as little as 1 fmol of ubiquitin. More complete peptide coverage for 100 fmol of a BSA tryptic digest, and increased sensitivity of drugs spiked in urine and saliva were observed after ammonium salt addition to the 3-NBN matrix. PMID:26122522

  18. Depositional ice nucleation on solid ammonium sulfate and glutaric acid particles

    Directory of Open Access Journals (Sweden)

    K. J. Baustian

    2010-03-01

    Full Text Available Heterogeneous ice nucleation on solid ammonium sulfate and glutaric acid particles was studied using optical microscopy and Raman spectroscopy. Optical microscopy was used to detect selective nucleation events as water vapor was slowly introduced into an environmental sample cell. Particles that nucleated ice were dried via sublimation and examined in detail using Raman spectroscopy. Depositional ice nucleation is highly selective and occurred preferentially on just a few ammonium sulfate and glutaric acid particles in each sample. For freezing temperatures between 214 K and 235 K an average ice saturation ratio of S = 1.10±0.07 for solid ammonium sulfate was observed. Over the same temperature range, S values observed for ice nucleation on glutaric acid particles increased from 1.2 at 235 K to 1.6 at 218 K. Experiments with externally mixed particles further show that ammonium sulfate is a more potent ice nucleus than glutaric acid. Our results suggest that heterogeneous nucleation on ammonium sulfate may be an important pathway for atmospheric ice nucleation and cirrus cloud formation when solid ammonium sulfate aerosol particles are available for ice formation. This pathway for ice formation may be particularly significant near the tropical tropopause region where sulfates are abundant and other species known to be good ice nuclei are depleted.

  19. Study of the crystal structure of double ammonium hafnium sulfate of the (NH4)4Hf(SO4)4x4H2O composition

    International Nuclear Information System (INIS)

    Two new double compounds of (NH4)2Hf(SO4)3x2H2O and (NH4)4Hf(SO4)4x4H2O have been studied. The second compound which forms needle transparent crystals of monoclinic singony, has been studied by the X-ray analysis. The unit cell parametres are as follows: a = 18.12(3), b = 14.89(3), c = 7.25(3) A, γ = 95.5 deg (5), spatial group P2/b, N=4. The first structure may be described as an islet structure. Besides basic valent bonds, it contains numerous intermolecular contacts and hydrogen bonds formed by water molecules and ammonium ions

  20. 磷石膏转化制硫酸铵的发展前景分析%Development prospect of preparation of ammonium sulfate from phosphogypsum

    Institute of Scientific and Technical Information of China (English)

    赵建国; 张应虎; 张宗凡; 孙文中; 张峻; 陈树林

    2013-01-01

    分析指出硫酸铵产品在中国肥料、工业及出口应用领域均存在持续增长的消费空间;传统产业及烟气脱硫副产硫酸铵产能的增长难于满足消费增长的需要;磷石膏转化制硫酸铵具有产能扩展空间大的优势;国内磷石膏转化制硫酸铵的产业化技术基本成熟,副产碳酸钙渣的较佳用途是作酸性土壤改良剂.定量分析了产品售价对项目可接受氨价及需补贴资金的影响,给出了有补贴和无补贴资金时使项目经济可行的产品售价.指出磷石膏转化制硫酸铵在有条件的高浓磷复肥企业会有较好的发展前景.%Ammonium sulfate products have a sustainedly growing consumption space in China's fertilizer,industry,and export application fields.The ammonium sulfate's capacity growth of traditional industry and of by-product of flue gas desulfurization is difficult to meet the requirement of consumption growth.Preparation of ammonium sulfate from phosphogypsum has the advantage of wider capacity increasing space.The domestic industrial preparation technology of ammonium sulfate from phosphogypsum is mature,and the better use of its by-product calcium carbonate slag is to be the acidic soil improver.The influence of product sales price on the project acceptable ammonia price and on required capital subsidy is quantitatively analyzed,and the project economically viable sales prices with and without capital subsidy are given.It is also pointed out that the preparation of ammonium sulfate from phosphogypsum will have a good development prospect in some conditional enter prises of high-concentration phosphoric compound fertilizer.

  1. High Pressure Burn Rate Measurements on an Ammonium Perchlorate Propellant

    Energy Technology Data Exchange (ETDEWEB)

    Glascoe, E A; Tan, N

    2010-04-21

    High pressure deflagration rate measurements of a unique ammonium perchlorate (AP) based propellant are required to design the base burn motor for a Raytheon weapon system. The results of these deflagration rate measurements will be key in assessing safety and performance of the system. In particular, the system may experience transient pressures on the order of 100's of MPa (10's kPSI). Previous studies on similar AP based materials demonstrate that low pressure (e.g. P < 10 MPa or 1500 PSI) burn rates can be quite different than the elevated pressure deflagration rate measurements (see References and HPP results discussed herein), hence elevated pressure measurements are necessary in order understand the deflagration behavior under relevant conditions. Previous work on explosives have shown that at 100's of MPa some explosives will transition from a laminar burn mechanism to a convective burn mechanism in a process termed deconsolidative burning. The resulting burn rates that are orders-of-magnitude faster than the laminar burn rates. Materials that transition to the deconsolidative-convective burn mechanism at elevated pressures have been shown to be considerably more violent in confined heating experiments (i.e. cook-off scenarios). The mechanisms of propellant and explosive deflagration are extremely complex and include both chemical, and mechanical processes, hence predicting the behavior and rate of a novel material or formulation is difficult if not impossible. In this work, the AP/HTPB based material, TAL-1503 (B-2049), was burned in a constant volume apparatus in argon up to 300 MPa (ca. 44 kPSI). The burn rate and pressure were measured in-situ and used to calculate a pressure dependent burn rate. In general, the material appears to burn in a laminar fashion at these elevated pressures. The experiment was reproduced multiple times and the burn rate law using the best data is B = (0.6 {+-} 0.1) x P{sup (1.05{+-}0.02)} where B is the burn

  2. Differences in the reactivity of ammonium salts with methylamine

    Directory of Open Access Journals (Sweden)

    Y. Liu

    2012-06-01

    Full Text Available The heterogeneous uptake of methylamine (MA onto (NH42SO4, NH4HSO4, NH4NO3 and NH4Cl was investigated using a Knudsen cell reactor coupled to a quadrupole mass spectrometer, in situ Raman spectrometer and theoretical calculations. Exchange reactions were observed between MA and NH4NO3, (NH42SO4, and NH4Cl were observed at 298 K. Simple acid-base reaction for MA was found taking place on NH4HSO4. CH3NH3NO3 and CH3NH3Cl are not stable at low pressure and have higher dissociation vapor pressure than methylammonium sulfate. The observed uptake coefficients of MA on (NH42SO4, NH4HSO4, NH4NO3 and NH4Cl at 298 K were measured to be 6.30±1.03×10−3, 1.78±0.36×10−2, 8.79±1.99×10−3 and 2.29±0.28×10−3, respectively. A linear free energy relationship was found for the heterogeneous reactions between MA and NH4Cl, (NH42SO4 and NH4NO3. Namely, the natural logarithm of uptake coefficients of MA on these ammonium salts is linearly related to the electrostatic potential of the H atom in the NH4+ group.

  3. Nutrient release and ammonium sorption by poultry litter and wood biochars in stormwater treatment.

    Science.gov (United States)

    Tian, Jing; Miller, Valentina; Chiu, Pei C; Maresca, Julia A; Guo, Mingxin; Imhoff, Paul T

    2016-05-15

    The feasibility of using biochar as a filter medium in stormwater treatment facilities was evaluated with a focus on ammonium retention. Successive batch extractions and batch ammonium sorption experiments were conducted in both deionized (DI) water and artificial stormwater using poultry litter (PL) and hardwood (HW) biochars pyrolyzed at 400°C and 500°C. No measureable nitrogen leached from HW biochars except 0.07 μmol/g of org-N from 400°C HW biochar. PL biochar pyrolyzed at 400°C leached 120-127 μmol/g of nitrogen but only 7.1-8.6 μmol/g of nitrogen when pyrolyzed at 500°C. Ammonium sorption was significant for all biochars. At a typical ammonium concentration of 2mg/L in stormwater, the maximum sorption was 150 mg/kg for PL biochar pryolyzed at 400°C. In stormwater, ion competition (e.g. Ca(2+)) suppressed ammonium sorption compared to DI water. Surprisingly, ammonium sorption was negatively correlated to the BET surface area of the tested biochars, but increased linearly with cation exchange capacity. Cation exchange capacity was the primary mechanism controlling ammonium sorption and was enhanced by pyrolysis at 400°C, while BET surface area was enhanced by pyrolysis at 500°C. The optimal properties (BET surface area, CEC, etc.) of biochar as a sorbent are not fixed but depend on the target pollutant. Stormwater infiltration column experiments in sand with 10% biochar removed over 90% of ammonium with influent ammonium concentration of 2mg/L, compared to only 1.7% removal in a sand-only column, indicating that kinetic limitations on sorption were minor for the storm conditions studied. Hardwood and poultry litter biochar pyrolyzed at 500°C and presumably higher temperature may be viable filter media for stormwater treatment facilities, as they showed limited release of organic and inorganic nutrients and acceptable ammonium sorption. PMID:26938322

  4. 利用硫铵母液生产NPK复肥%NPK compound fertilizer production from ammonium sulfate mother liquor

    Institute of Scientific and Technical Information of China (English)

    念吉红

    2015-01-01

    介绍云峰分公司利用硫铵母液生产55% (15-30-10) NPK复肥的工艺流程、控制指标及特点.利用硫铵母液生产NPK复肥,可利用废弃资源,降低生产成本,同时增加了NPK复肥中的S含量,具有很好的应用前景.

  5. Effects of organic moieties on the photoluminescence spectra of perovskite-type tin bromide based compounds

    Science.gov (United States)

    Papavassiliou, George C.; Vidali, Maria-Sofia; Pagona, Georgia; Mousdis, George A.; Karousis, Nikolaos; Koutselas, Ioannis

    2015-04-01

    The photoluminescence (PL) and optical absorption (OA) spectra of some compounds of the type (SC)SnBr3, (BC)2SnBr4, and (SC)(BC)2Sn2Br7 (where SC is CH3NH3 + or Cs+; BC is C4H9NH3 + ,CH3C6H4CH2NH3 + ,C12H25NH3 + ,C18H37NH3 + and 1-naphthylmethyl ammonium group), in the forms of thin deposits on several substrates, are investigated. Generally, using the 350 nm as excitation line, the obtained PL spectra of compounds of the type (BC)2SnBr4 with short alkyl chain-length in the alkyl ammonium moiety, show broad and strong bands. For example, the PL spectra of compound (C4H9NH3)2SnBr4 exhibit a weak band at ca 475 nm, attributed to free-excitons and a broad and strong band at ca 570 nm, attributed to radiative decay of self-trapped excitons in the inorganic moiety. This is a bright yellow-orange emission, which can be seen by naked eye, even at room temperature. In the case of the compounds with long alkyl chain-length in the alkyl ammonium moiety, the PL spectra are dominated by an excitonic band, which occurs close to the corresponding fundamental OA edge. The PL spectrum of (1-naphthylmethyl ammonium)2SnBr4 shows the strong red band with main maxima at ca 603 and 642 nm, arising from tetramers of naphthyl moieties. Also, the PL spectra of the compounds of the type (SC)SnBr3 and (SC)(BC)2Sn2Br7, after grinding, show strong bands at 600-620 nm.

  6. Thermal stability and kinetics of decomposition of ammonium nitrate in the presence of pyrite.

    Science.gov (United States)

    Gunawan, Richard; Zhang, Dongke

    2009-06-15

    The interaction between ammonium nitrate based industrial explosives and pyrite-rich minerals in mining operations can lead to the occurrence of spontaneous explosion of the explosives. In an effort to provide a scientific basis for safe applications of industrial explosives in reactive mining grounds containing pyrite, ammonium nitrate decomposition, with and without the presence of pyrite, was studied using a simultaneous Differential Scanning Calorimetry and Thermogravimetric Analyser (DSC-TGA) and a gas-sealed isothermal reactor, respectively. The activation energy and the pre-exponential factor of ammonium nitrate decomposition were determined to be 102.6 kJ mol(-1) and 4.55 x 10(7)s(-1) without the presence of pyrite and 101.8 kJ mol(-1) and 2.57 x 10(9)s(-1) with the presence of pyrite. The kinetics of ammonium nitrate decomposition was then used to calculate the critical temperatures for ammonium nitrate decomposition with and without the presence of pyrite, based on the Frank-Kamenetskii model of thermal explosion. It was shown that the presence of pyrite reduces the temperature for, and accelerates the rate of, decomposition of ammonium nitrate. It was further shown that pyrite can significantly reduce the critical temperature of ammonium nitrate decomposition, causing undesired premature detonation of the explosives. The critical temperature also decreases with increasing diameter of the blast holes charged with the explosive. The concept of using the critical temperature as indication of the thermal stability of the explosives to evaluate the risk of spontaneous explosion was verified in the gas-sealed isothermal reactor experiments. PMID:19056177

  7. Thermal stability and kinetics of decomposition of ammonium nitrate in the presence of pyrite

    Energy Technology Data Exchange (ETDEWEB)

    Gunawan, Richard, E-mail: R.Gunawan@curtin.edu.au [Centre for Fuels and Energy, Curtin University of Technology, G.P.O. Box U1987, Perth, WA 6845 (Australia); Zhang Dongke [Centre for Petroleum, Fuels and Energy, School of Mechanical Engineering (M050), University of Western Australia, 35 Stirling Highway, Crawley WA 6009 (Australia)

    2009-06-15

    The interaction between ammonium nitrate based industrial explosives and pyrite-rich minerals in mining operations can lead to the occurrence of spontaneous explosion of the explosives. In an effort to provide a scientific basis for safe applications of industrial explosives in reactive mining grounds containing pyrite, ammonium nitrate decomposition, with and without the presence of pyrite, was studied using a simultaneous Differential Scanning Calorimetry and Thermogravimetric Analyser (DSC-TGA) and a gas-sealed isothermal reactor, respectively. The activation energy and the pre-exponential factor of ammonium nitrate decomposition were determined to be 102.6 kJ mol{sup -1} and 4.55 x 10{sup 7} s{sup -1} without the presence of pyrite and 101.8 kJ mol{sup -1} and 2.57 x 10{sup 9} s{sup -1} with the presence of pyrite. The kinetics of ammonium nitrate decomposition was then used to calculate the critical temperatures for ammonium nitrate decomposition with and without the presence of pyrite, based on the Frank-Kamenetskii model of thermal explosion. It was shown that the presence of pyrite reduces the temperature for, and accelerates the rate of, decomposition of ammonium nitrate. It was further shown that pyrite can significantly reduce the critical temperature of ammonium nitrate decomposition, causing undesired premature detonation of the explosives. The critical temperature also decreases with increasing diameter of the blast holes charged with the explosive. The concept of using the critical temperature as indication of the thermal stability of the explosives to evaluate the risk of spontaneous explosion was verified in the gas-sealed isothermal reactor experiments.

  8. Root ABA Accumulation Enhances Rice Seedling Drought Tolerance under Ammonium Supply: Interaction with Aquaporins.

    Science.gov (United States)

    Ding, Lei; Li, Yingrui; Wang, Ying; Gao, Limin; Wang, Min; Chaumont, François; Shen, Qirong; Guo, Shiwei

    2016-01-01

    In previous studies, we demonstrated that ammonium nutrition enhances the drought tolerance of rice seedlings compared to nitrate nutrition and contributes to a higher root water uptake ability. It remains unclear why rice seedlings maintain a higher water uptake ability when supplied with ammonium under drought stress. Here, we focused on the effects of nitrogen form and drought stress on root abscisic acid (ABA) concentration and aquaporin expression using hydroponics experiments and stimulating drought stress with 10% PEG6000. Drought stress decreased the leaf photosynthetic rate and stomatal conductivity and increased the leaf temperature of plants supplied with either ammonium or nitrate, but especially under nitrate supply. After 4 h of PEG treatment, the root protoplast water permeability and the expression of root PIP and TIP genes decreased in plants supplied with ammonium or nitrate. After 24 h of PEG treatment, the root hydraulic conductivity, the protoplast water permeability, and the expression of some aquaporin genes increased in plants supplied with ammonium compared to those under non-PEG treatment. Root ABA accumulation was induced by 24 h of PEG treatment, especially in plants supplied with ammonium. The addition of exogenous ABA decreased the expression of PIP and TIP genes under non-PEG treatment but increased the expression of some of them under PEG treatment. We concluded that drought stress induced a down-regulation of aquaporin expression, which appeared earlier than did root ABA accumulation. With continued drought stress, aquaporin expression and activity increased due to root ABA accumulation in plants supplied with ammonium. PMID:27559341

  9. Root ABA Accumulation Enhances Rice Seedling Drought Tolerance under Ammonium Supply: Interaction with Aquaporins

    Science.gov (United States)

    Ding, Lei; Li, Yingrui; Wang, Ying; Gao, Limin; Wang, Min; Chaumont, François; Shen, Qirong; Guo, Shiwei

    2016-01-01

    In previous studies, we demonstrated that ammonium nutrition enhances the drought tolerance of rice seedlings compared to nitrate nutrition and contributes to a higher root water uptake ability. It remains unclear why rice seedlings maintain a higher water uptake ability when supplied with ammonium under drought stress. Here, we focused on the effects of nitrogen form and drought stress on root abscisic acid (ABA) concentration and aquaporin expression using hydroponics experiments and stimulating drought stress with 10% PEG6000. Drought stress decreased the leaf photosynthetic rate and stomatal conductivity and increased the leaf temperature of plants supplied with either ammonium or nitrate, but especially under nitrate supply. After 4 h of PEG treatment, the root protoplast water permeability and the expression of root PIP and TIP genes decreased in plants supplied with ammonium or nitrate. After 24 h of PEG treatment, the root hydraulic conductivity, the protoplast water permeability, and the expression of some aquaporin genes increased in plants supplied with ammonium compared to those under non-PEG treatment. Root ABA accumulation was induced by 24 h of PEG treatment, especially in plants supplied with ammonium. The addition of exogenous ABA decreased the expression of PIP and TIP genes under non-PEG treatment but increased the expression of some of them under PEG treatment. We concluded that drought stress induced a down-regulation of aquaporin expression, which appeared earlier than did root ABA accumulation. With continued drought stress, aquaporin expression and activity increased due to root ABA accumulation in plants supplied with ammonium. PMID:27559341

  10. Higher Ammonium Transamination Capacity Can Alleviate Glutamate Inhibition on Winter Wheat (Triticum aestivum L.) Root Growth under High Ammonium Stress.

    Science.gov (United States)

    Wang, Feng; Gao, Jingwen; Liu, Yang; Tian, Zhongwei; Muhammad, Abid; Zhang, Yixuan; Jiang, Dong; Cao, Weixing; Dai, Tingbo

    2016-01-01

    Most of the studies about NH4+ stress mechanism simply address the effects of free NH4+, failing to recognize the changed nitrogen assimilation products. The objective of this study was to elucidate the effects of glutamate on root growth under high ammonium (NH4+) conditions in winter wheat (Triticum aestivum L.). Hydroponic experiments were conducted using two wheat cultivars, AK58 (NH4+-sensitive) and Xumai25 (NH4+-tolerant) with either 5 mM NH4+ nitrogen (AN) as stress treatment or 5 mM nitrate (NO3-) nitrogen as control. To evaluate the effects of NH4+-assimilation products on plant growth, 1 μM L-methionine sulfoximine (MSO) (an inhibitor of glutamine synthetase (GS)) and 1 mM glutamates (a primary N assimilation product) were added to the solutions, respectively. The AN significantly reduced plant biomass, total root length, surface area and root volume in both cultivars, but less effect was observed in Xumai25. The inhibition effects were alleviated by the application of MSO but strengthened by the application of glutamate. The AN increased the activities of GS, glutamate dehydrogenase (GDH) in both cultivars, resulting in higher glutamate contents. However, its contents were decreased by the application of MSO. Compared to AK58, Xumai25 showed lower glutamate contents due to its higher activities of glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT). With the indole-3-acetic acid (IAA) contents decreasing in roots, the ratio of shoot to root in IAA was increased, and further increased by the application of glutamate, and reduced by the application of MSO, but the ratio was lower in Xumai25. Meanwhile, the total soluble sugar contents and its root to shoot ratio also showed similar trends. These results indicate that the NH4+-tolerant cultivar has a greater transamination ability to prevent glutamate over-accumulation to maintain higher IAA transport ability, and consequently promoted soluble sugar transport to roots, further

  11. Precipitation of ammonium from concentrated industrial wastes as struvite: a search for the optimal reagents.

    Science.gov (United States)

    Borojovich, Eitan J C; Münster, Meshulam; Rafailov, Gennady; Porat, Ze'ev

    2010-07-01

    Precipitation of struvite (MgNH4PO4) is a known process for purification of wastewater from high concentrations of ammonium. The optimal conditions for precipitation are basic pH (around 9) and sufficient concentrations of magnesium and phosphate ions. In this work, we accomplished efficient precipitation of ammonium from concentrated industrial waste stream by using magnesium oxide (MgO) both as a source of magnesium ions and as a base. Best results were obtained with technical-grade MgO, which provided 99% removal of ammonium. Moreover, ammonium removal occurred already at pH 7, and the residual ammonium concentration (50 mg/L) remained constant upon addition of more MgO without rising again, as occurs with sodium hydroxide (NaOH). This process may have two other advantages; it also can be relevant for the problem of uncontrolled precipitation of struvite in the supernatant of anaerobic sludge treatment plants, and the precipitate can be used as a fertilizer. PMID:20669719

  12. Evaluation of quaternary ammonium halides for removal of methyl iodide from flowing air streams

    International Nuclear Information System (INIS)

    The quaternary ammonium halides of several tertiary amines were used as impregnants on activated carbon and were tested for methyl iodide penetration in accordance with test Method A, ASTM D3803, 1979, ''Standard Test Methods for Radio-iodine Testing of Nuclear Grade Gas Phase Adsorbents''. The results suggest that the primary removal mechanism for methyl iodide-131 is isotopic exchange with the quaternary ammonium halide. For example, a 5 wt% impregnation of each of the tetramethyl, tetraethyl, tetrapropyl and tetrabutyl ammonium iodides on activated carbon yielded percent penetrations of 0.47, 0.53, 0.78, and 0.08 respectively when tested according to Method A of ASTM D3803. A sample impregnated with 5% tetramethyl ammonium hydroxide gave a methyl iodide penetration of 64.87%, thus supporting the isotopic exchange mechanism for removal. It has been a generally held belief that the success of tertiary amines as impregnants for radioiodine removal is a result of their ability to complex with the methyl iodide. The results of the work indicates that the superiority of the tertiary amines similar to triethylene diamine and quinuclidine, when compared to their straight chain analogs, is a result of their ease in reacting with methyl iodide-127 to form the quaternary ammonium iodide followed by isotopic exchange

  13. Origins of the subsurface ammonium maximum in the Southeast Bering Sea

    Science.gov (United States)

    Mordy, Calvin W.; Stabeno, Phyllis J.; Righi, Dylan; Menzia, Frederick A.

    2008-08-01

    In the Bering Sea, it has long been argued that ammonium-rich bottom water from the middle shelf of Bristol Bay is tidally diffused seaward resulting in a mid-depth ammonium tongue over the outer shelf. Weak horizontal mean flows in the region (relative to an especially strong tidal component) support this contention. We examined the distribution of ammonium further north in the vicinity of the Pribilof Islands. On the middle shelf, bottom waters had concentrations of 4-7 μmol kg -1, and over the outer shelf there was a mid-depth ammonium tongue. Optimal multiparameter analysis of hydrographic data suggested that bottom waters from the middle shelf were prevalent across the outer shelf, and could account for this ammonium tongue. Drifter tracks demonstrated that middle shelf water was incorporated into a westward flow along the shelf break south of St. George Island, and mean flows derived from several decades of drifter tracks also show prominent cross-shelf advection in the region. This was consistent with a scalar argument suggesting that, in the vicinity of the Pribilof Islands, the seaward movement of middle shelf water, and loss of nitrogen over the middle shelf, was the result of advection rather than tidally driven lateral diffusion.

  14. Nitrogen (15N) recovery from ammonium and nitrate applied to the soil by sugar cane

    International Nuclear Information System (INIS)

    An experiment was developed in a field aimed to compare the recovery of the ammonium-15 N and nitrate-15 N by the sugar cane plants harvested mechanically without burning. A rate of 70 kg ha-1 of N was applied as ammonium nitrate, in strip, onto cultural residues. Two lineal meters micropots were used. They received the fertilizer labeled with 15 N. Two treatments were established using labeled ammonium (NH4+-15 N) or nitrate (NO3-15 N). Two months after fertilization, four samples of the aerial part (two lineal meters) for treatment in the portions that did not receive the fertilizer-15 N, were taken in order to evaluated the fitomass production (Mg ha-1) and N-total accumulated (kg ha-1). This evaluation was repeated every two months up to complete five of them. Two leaves (leaves with 3 deg C visible auricle) were collected from plants that were in a middle of the micropots (15 N) and in corresponding positions in the adjacent rows, to evaluated the concentration of 15 N. There was a larger absorption of the nitrate-N (30.5%) than of the ammonium-N (21.2%). On the other hand, in the soil the results showed larger ammonium-15 N residual effect concentration, probably due to microorganism immobilization. (author)

  15. Enhanced Ionization of Phosphopeptide Using Ammonium Phosphate as Matrix Additive by MALDI-MS

    Institute of Scientific and Technical Information of China (English)

    ZHANG,Ying; LU,Hao-Jie; YANG,Peng-Yuan

    2008-01-01

    A new method based upon adding ammonium phosphate as a matrix additive to enhance the ionization efficiency of phosphopeptide in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) was described. Furthermore, influences of different phosphate salts at various concentrations on the ionization efficiency of phosphopeptide were investigated systematically, finding that the signal intensity for phosphopeptide 48FQ[pS]EEQQQTEDELQDK63 digested from β-casein were 5 to 8 times increased in an optimized condition with 10 mmol/L ammonium monobasic phosphate or 3 to 4 times increased with 10 mmol/L ammonium dibasic phosphate as additive to matrix 2,5-dihydroxybenzoic acid, respectively. Compared with the most optimized matrix system that was currently reported for special ionization of phosphopeptides, the signal intensity of this phosphopeptide was also enhanced by twice when introducing 5 mmol/L ammonium dibasic phosphate into matrix 2,4,6-trihydroxyacetophenone. In addition, the mechanism was also discussed, assuming that the cooperation function of ammonium cation and phosphate anion was of great importance in enhancing the ionization efficiency of phosphopeptide in MALDI-MS.

  16. Determination of ammonium on an integrated microchip with LED-induced fluorescence detection

    Institute of Scientific and Technical Information of China (English)

    Shuhua Xue; Katsumi Uchiyama; Hai-fang Li

    2012-01-01

    A simply fabricated microfluidic device integrated with a fluorescence detection system has been developed for on-line determination of ammonium in aqueous samples.A 365-nm light-emitting diode(LED)as an excitation source and a minor band pass filter were mounted into a polydimethylsiloxane(PDMS)-based microchip for the purpose of miniaturization of the entire analytical system.The ammonium sample reacted with o-phthaldialdehyde(OPA)on-chip with sodium sulfite as reducing reagent to produce a fluorescent isoindole derivative,which can emit fluorescence signal at about 425 nm when excited at 365 nm.Effects of pH,flow rate of solutions,concentrations of OPA-reagent,phosphate and sulfite salt were investigated.The calibration curve of ammonium in the range of 0.018-1.8 μg/mL showed a good linear relationship with R2 =0.9985,and the detection limit was(S/N =3)3.6 × 10-4 μg/mL.The relative standard deviation was 2.8%(n =11)by calculating at 0.18 μg/mL ammonium for repeated detection.The system was applied to determine the ammonium concentration in rain and river waters,even extent to other analytes fluorescence detection by the presented device.

  17. Preparation of anhydrous magnesium chloride in a gas-solid reaction with ammonium carnallite

    Institute of Scientific and Technical Information of China (English)

    Zhou Ningbo; Chen Baizhen; He Xinkuai; Li Yibing

    2006-01-01

    Dehydrated ammonium carnallite was synthesized with bischofite from salt lake and ammonium chloride solution in a 1:1 molar ratio of MgCl2:NH4Cl,dehydrated at 160℃ for about 4 h.The yield was above 85%.The product was then mixed with solid-state ammonium chloride with a 1:4 mass ratio for the further dehydration at 410℃.The decomposition of NH4Cl made a pressure of NH3 at 30.5 kPa to prevent the hydrolysis of ammonium carnallite.The anhydration of magnesium chloride was achieved at 700℃.The results showed that anhydrous magnesium chloride contains magnesium oxide in an amount that was less than 0.1% by weight.XRD pattern and SEM micrograph showed a good dispersion of ammonium carnallite and anhydrous magnesium chloride crystals with well-distributed big grains,just enough to meet the need for the production of magnesium metal in the electrolysis process.

  18. Isolation and identification of bacteria responsible for simultaneous anaerobic ammonium and sulfate removal

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Sulfate-dependent anaerobic ammonium oxidation is a novel biological reaction,in which ammonium is oxidized with sulfate as the electron acceptor under anoxic conditions.Ammonium and sulfate are cosmopolitan chemical species which are an integral part of the global nitrogen and sulfur cycles.A detailed exploration of sulfate-dependent anaerobic ammonium oxidation is quite practical.In this work,a bacterial strain named ASR has been isolated from an anaerobic ammonia and sulfate removing reactor working under steady-state.On the basis of electron microscopy,physiological tests and 16S rDNA phylogenetic sequence analysis,the strain ASR is found to be related to Bacillus benzoevorans.According to the biological carbon source utilization test,the strain ASR could use many carbon sources.Its optimum pH value and temperature were 8.5 and 30 °C,respectively.The test proves that the strain ASR is able to use sulfate to oxidize ammonia anaerobically.The maximum ammonia and sulfate removal rates were 44.4% and 40.0%,respectively.The present study provided biological evidence for the confirmation and development of sulfate-dependent anaerobic ammonium oxidation and brought new insights into the global nitrogen and sulfur cycles.

  19. Evaluation of natural zeolite clinoptilolite efficiency for the removal of ammonium and nitrate from aquatic solutions

    Directory of Open Access Journals (Sweden)

    Mozhdeh Murkani

    2015-01-01

    Full Text Available Background: Surface water and groundwater pollution with various forms of nitrogen such as ammonium and nitrate ions is one of the main environmental risks. The major objectives of this study were to evaluate the capacity of natural zeolite (clinoptilolite to remove NO3– and NH4+ from polluted water under both batch and column conditions. Methods: The laboratory batch and column experiments were conducted to investigate the feasibility of clinoptilolite as the adsorbent for removal of nitrate (NO3– and ammonium (NH4+ ions from aqueous solution. The effects of pH, clinoptilolite dosage, contact time, and initial metal ion concentration on NO3– and NH4+ removal were investigated in a batch system. Results: Equilibrium time for NO3– and NH4+ ions exchange was 60 minutes and the optimum adsorbent dosage for their removal was 1 and 2.5 g/L, respectively. The adsorption isotherm of reaction (r> 0.9 and optimum entered concentration of ammonium and nitrate (30 and 6.5 mg/L, respectively were in accordance with Freundlich isotherm model. The ammonium removal rate increased by 98% after increasing the contact time. Conclusion: Our findings confirmed that natural Clinoptilolite can be used as one of effective, suitable, and low-costing adsorbent for removing ammonium from polluted waters.

  20. Accurate Measurement of the in vivo Ammonium Concentration in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Hugo F. Cueto-Rojas

    2016-04-01

    Full Text Available Ammonium (NH4+ is the most common N-source for yeast fermentations, and N-limitation is frequently applied to reduce growth and increase product yields. While there is significant molecular knowledge on NH4+ transport and assimilation, there have been few attempts to measure the in vivo concentration of this metabolite. In this article, we present a sensitive and accurate analytical method to quantify the in vivo intracellular ammonium concentration in Saccharomyces cerevisiae based on standard rapid sampling and metabolomics techniques. The method validation experiments required the development of a proper sample processing protocol to minimize ammonium production/consumption during biomass extraction by assessing the impact of amino acid degradation—an element that is often overlooked. The resulting cold chloroform metabolite extraction method, together with quantification using ultra high performance liquid chromatography-isotope dilution mass spectrometry (UHPLC-IDMS, was not only more sensitive than most of the existing methods but also more accurate than methods that use electrodes, enzymatic reactions, or boiling water or boiling ethanol biomass extraction because it minimized ammonium consumption/production during sampling processing and interference from other metabolites in the quantification of intracellular ammonium. Finally, our validation experiments showed that other metabolites such as pyruvate or 2-oxoglutarate (αKG need to be extracted with cold chloroform to avoid measurements being biased by the degradation of other metabolites (e.g., amino acids.

  1. Excretion of ammonium by a nifL mutant of Azotobacter vinelandii fixing nitrogen.

    Science.gov (United States)

    Bali, A; Blanco, G; Hill, S; Kennedy, C

    1992-05-01

    A mutation in the gene upstream of nifA in Azotobacter vinelandii was introduced into the chromosome to replace the corresponding wild-type region. The resulting mutant, MV376, produced nitrogenase constitutively in the presence of 15 mM ammonium. When introduced into a nifH-lacZ fusion strain, the mutation permitted beta-galactosidase production in the presence of ammonium. The gene upstream of nifA is therefore designated nifL because of its similarity to the Klebsiella pneumoniae nifL gene in proximity to nifA, in mutant phenotype, and in amino acid sequence of the gene product. The A. vinelandii nifL mutant MV376 excreted significant quantities of ammonium (approximately 10 mM) during diazotrophic growth. In contrast, ammonium excretion during diazotrophy was much lower in a K. pneumoniae nifL deletion mutant (maximum, 0.15 mM) but significantly higher than in NifL+ K. pneumoniae. The expression of the A. vinelandii nifA gene, unlike that of K. pneumoniae, was not repressed by ammonium. PMID:1622243

  2. An Electronic Tongue Designed to Detect Ammonium Nitrate in Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Inmaculada Campos

    2013-10-01

    Full Text Available An electronic tongue has been developed to monitor the presence of ammonium nitrate in water. It is based on pulse voltammetry and consists of an array of eight working electrodes (Au; Pt; Rh; Ir; Cu; Co; Ag and Ni encapsulated in a stainless steel cylinder. In a first step the electrochemical response of the different electrodes was studied in the presence of ammonium nitrate in water in order to further design the wave form used in the voltammetric tongue. The response of the electronic tongue was then tested in the presence of a set of 15 common inorganic salts; i.e.; NH4NO3; MgSO4; NH4Cl; NaCl; Na2CO3; (NH42SO4; MgCl2; Na3PO4; K2SO4; K2CO3; CaCl2; NaH2PO4; KCl; NaNO3; K2HPO4. A PCA plot showed a fairly good discrimination between ammonium nitrate and the remaining salts studied. In addition Fuzzy Art map analyses determined that the best classification was obtained using the Pt; Co; Cu and Ni electrodes. Moreover; PLS regression allowed the creation of a model to correlate the voltammetric response of the electrodes with concentrations of ammonium nitrate in the presence of potential interferents such as ammonium chloride and sodium nitrate.

  3. Electrochemical decontamination of metallic wastes contaminated with uranium compounds in a neutral salt electrolyte

    International Nuclear Information System (INIS)

    Electrochemical decontamination process has been applied for recycle or self disposal with authorization of large amount of metallic wastes contaminated with uranium compounds such as UO2, ammonium uranyl carbonate (AUC), ammonium di-uranate (ADU), and uranyl nitrate (UN) with tributylphosphate (TBP) and dodecane, which are generated by dismantling the contaminated system components and equipment of a retired uranium conversion plant in Korea Atomic Energy Research Institute (KAERI). Electrochemical decontamination for metallic wastes contaminated with uranium compounds was evaluated through the experiments on the electrolytic dissolution of stainless steel as the material of the system components in neutral concentration of electrolyte on the dissolution of the materials were evaluated. Decontamination performance tests using the specimens taken from a uranium conversion plant were quite successful with the application electrochemical decontamination conditions obtained through the basic studies on the electrolytic dissolution of structural material of the system components

  4. Comparative Study of Laterite and Bentonite Based Organoclays: Implications of Hydrophobic Compounds Remediation from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Muhammad Nafees

    2013-01-01

    Full Text Available Four cost effective organoclays were synthesized, characterized, and studied for the sorption of hydrophobic compounds (edible oil/grease and hydrocarbon oil from aqueous solutions. Organoclays were prepared by cation exchange reaction of lattice ions (present onto the surface of laterite and bentonite clay minerals with two surfactants, hexadecyl trimethyl ammonium chloride (HDTMA-Cl and tetradecyl trimethyl ammonium bromide (TDTMA-Br. Fourier transform infrared spectroscopy and scanning electron microscopy were used for the characterization of synthesized organoclays. It was found that the amount of surfactant loading and the nature of the surfactant molecules used in the syntheses of organoclay strongly affect the sorption capacity of the clay mineral. Further, it was found that both the laterite and bentonite based organoclays efficiently removed the edible and hydrocarbon oil content from lab prepared emulsions; however, the adsorption capacity of clay mineral was greatly influenced by the nature of hydrophobic compounds as well.

  5. The mechanism for production of beryllium fluoride from the product of ammonium fluoride processing of beryllium- containing raw material

    Science.gov (United States)

    Kraydenko, R. I.; Dyachenko, A. N.; Malyutin, L. N.; Petlin, I. V.

    2016-06-01

    The technique of fluorite-phenacite-bertrandite ores from Russian Ermakovskoe deposit processing by ammonium bifluoride is described. To determine the temperature mode and the thermal dissociation mechanism of ammonium tetrafluoroberyllate (the product of ammonium-fluoride leaching of the ore) the TG/DTA have been carried out. By IR spectroscopy and XRD the semi-products of ammonium tetrafluoroberyllate thermal dissociation have been identified. The hygroscopic low-temperature beryllium fluoride forms higher than 380°C. The less hydroscopic form of BeF2 have been produced at 600°C.

  6. Pathway of ammonium assimilation in a marine diatom determined with the radiotracer 13N

    International Nuclear Information System (INIS)

    In unicellular algae, ammonium can be assimilated into glutamate through the action of glutamate dehydrogenase (GDH) or into glutamine through the sequential activities of glutamine synthetase and glutamate 2-oxoglutarate amidotransferase (GS-GOGAT pathway). We have shown that the first radio-labeled product of assimilation of 13NH4+ (t1/2 = 10 min) was glutamine in the marine diatom Thalassiosira pseudonana (Hustedt). When GS-GOGAT was inhibited with methionine sulfoximine, the incorporation of radioactivity into both glutamine and glutamate was blocked, implying that the radiolabeled glutamate is formed from glutamine. Glutamine was also the first labeled product when the intracellular concentration of ammonium was elevated by preincubation with unlabeled ammonium. The results indicate that the GS-GOGAT pathway is the primary pathway for the assimilation of nitrogen in T. pseudonana

  7. Preliminary Study On The Precipitation Of Ammonium Carbonate (AUC) From Uranylfluoride (UO2F2) Solution

    International Nuclear Information System (INIS)

    The preliminary studies on the precipitation process of ammonium uranyl carbonate (AUC)-(NH4)4UO2(CO3)3 from the UO2F2-HF solution system by using precipitation agent of ammonium carbonate (AC)-(NH4)2CO3 and on preparation ability of UO2 powder via AUC route are shown in this report. Our analysis results suggested that a product, identified as ammonium uranyl fluoride (AUF), was found along with the AUC precipitate. In order to prevent the formation of the undesirable AUF precipitate, the AUC precipitation process was carried out in the stable pH media ∼ 9, uranium concentration of 100 g/L and molar ratio of C to U ≥ 7.5. (author)

  8. Synthesis of nano-crystalline hydroxyapatite and ammonium sulfate from phosphogypsum waste

    Energy Technology Data Exchange (ETDEWEB)

    Mousa, Sahar, E-mail: dollyriri@yahoo.com [Inorganic Chemistry Department, National Research Centre, Dokki, P.O.Box:12622, Postal code: 11787 Cairo (Egypt); King Abdulaziz University, Science and Art College, Chemistry Department, Rabigh Campus, P.O. Box:344, Postal code: 21911 Rabigh (Saudi Arabia); Hanna, Adly [Inorganic Chemistry Department, National Research Centre, Dokki, P.O.Box:12622, Postal code: 11787 Cairo (Egypt)

    2013-02-15

    Graphical abstract: TEM micrograph of dried HAP at 800 °C. -- Abstract: Phosphogypsum (PG) waste which is derived from phosphoric acid manufacture by using wet method was converted into hydroxyapatite (HAP) and ammonium sulfate. Very simple method was applied by reacting PG with phosphoric acid in alkaline medium with adjusting pH using ammonia solution. The obtained nano-HAP was dried at 80 °C and calcined at 600 °C and 900 °C for 2 h. Both of HAP and ammonium sulfate were characterized by X-ray diffraction (XRD) and infrared spectroscopy (IR) to study the structural evolution. The thermal behavior of nano-HAP was studied; the particle size and morphology were estimated by using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). All the results showed that HAP nano-crystalline and ammonium sulfate can successfully be produced from phosphogypsum waste.

  9. Effect of ammonium on nitrous oxide emission during denitrification with different electron donors

    Institute of Scientific and Technical Information of China (English)

    Guangxue Wu; Xiaofeng Zhai; Chengai Jiang; Yuntao Guan

    2013-01-01

    Nitrous oxide (N2O) emission during denitrification is receiving intensive attention due to its high potential to cause greenhouse effects.In this study,denitrifiers were acclimated in sequencing batch reactors with methanol or acetate as the electron donor and nitrate as the electron acceptor.The effects of ammonium on N2O emission were examined in batch experiments with various electron donors.With the addition of ammonium,N2O emission increased under all the examined conditions compared to experiments without ammonium addition.With different electron donors,the highest ratio of N2O emission to the removed oxidized nitrogen was 0.70% for methanol,5.34% for acetate,and 34.79% for polyhydroxybutyrate.

  10. Experimental Research on Removing Suspended Solids and Ammonium Ions from Sludge Liquor

    Directory of Open Access Journals (Sweden)

    Kasparas Gražinskas

    2014-10-01

    Full Text Available The article investigates the processes of removing suspended solids and ammonium ions from sludge liquor. Experimental research was carried out at the Water Management Department laboratory of Vilnius Gediminas Technical University applying an experimental bench made of filters equipped with the zeolites of a different fraction and other appliances. Laboratory testing looked at the use of natural sorbent zeolite for removing ammonium ions from sludge liquor mixing liquid with powdered zeolite and filtering through zeolite filter media. Research was carried out employing the particles of zeolite 1.0–1.5 mm; 2.0–2.5 mm; 2.5–3.15 mm in diameter. The highest efficiency of removing ammonium ions reached 76% and was obtained using zeolite particles 2.0–2.5 mm in diameter.

  11. Expression, purification and crystallization of the ammonium transporter Amt-1 from Archaeoglobus fulgidus

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Susana L. A., E-mail: sandrad@uni-goettingen.de; Dickmanns, Antje; Ficner, Ralf; Einsle, Oliver, E-mail: sandrad@uni-goettingen.de [Abteilung Molekulare Strukturbiologie, Institut für Mikrobiologie und Genetik, Georg-August-Universität Göttingen, Justus-von-Liebig-Weg 11, 37077 Göttingen (Germany)

    2005-09-01

    The ammonium transporter Amt-1 from the cytoplasmic membrane of the hyperthermophilic archaeon A. fulgidus has been purified and crystallized. Ammonium transporters (Amts) are a class of membrane-integral transport proteins found in organisms from all kingdoms of life. Their key function is the transport of nitrogen in its reduced bioavailable form, ammonia, across cellular membranes, a crucial step in nitrogen assimilation for biosynthetic purposes. The genome of the hyperthermophilic archaeon Archaeoglobus fulgidus has been annotated with three individual genes for ammonium transporters, amt1–3, the roles of which are as yet unknown. The amt1 gene product has been produced by heterologous overexpression in Escherichia coli and the resulting protein has been purified to electrophoretic homogeneity. Crystals of Amt-1 have been obtained by sitting-drop vapour diffusion and diffraction data have been collected.

  12. Impact of flow conditions on ammonium uptake and microbial community structure in benthic biofilms

    Science.gov (United States)

    Arnon, Shai; Yanuka, Keren; Nejidat, Ali

    2010-05-01

    Excess nitrogen in surface waters is widely recognized to be a major global problem that adversely affects ecosystems, human health, and the economy. Today, most efforts to understand and model nutrient dynamics at large scales relies on macro-scale parameterization, such as mean channel geometry and velocity with uniform flow assumptions, as well as gross averages of in-situ nutrient transformation rates. However, there is increasing evidence that nutrient transformations in hyporheic zone are regulated by coupling between physical, chemical, and microbiological processes. Ignoring this greatly hinders the estimation of average biochemical transformation rates under the variable flow conditions found in aquatic systems. We used a combination of macro- and micro-scale observations in laboratory flumes to show that interplay between hydrodynamic transport, redox gradients, and microbial metabolism controls ammonium utilization by hyporheic microbial communities. Biofilm structural characteristics were quantified using denaturing gradient gel electrophoresis (DGGE) and real time PCR, while redox and pH gradients were measured using microelectrodes. We found that overlying velocities had profound effect on ammonium uptake due to mass transfer of ammonium from the bulk water to the benthic biofilms, but also due to the delivery of oxygen into the sediment bed. Under laminar flow conditions we didn't observe any change of ammonium uptake as a response to increase in overlying velocity. However, under non-laminar conditions we observe monotonic increase in ammonium uptake, with the greatest uptake under the fastest flow condition. We will discuss ammonium uptake rates results in the context of the different microbial communities and the micro-scale observations that were obtained using the microelectrodes. We anticipate that combined knowledge of the response of the microbial community and bulk nitrogen utilization rates to flow conditions will support the development of

  13. Degradation and bound-residue formation of nonylphenol in red soil and the effects of ammonium

    International Nuclear Information System (INIS)

    Fate of nonylphenol (NP) in soils and the effects of nitrogen fertilizers are unclear. Using 14C-tracer, we studied the aerobic and anaerobic degradation of 4-NP111 in a paddy red soil amended without and with ammonium chloride. Under oxic conditions, 4-NP111 had a half-life of 16.1 ± 1.6 days and minor mineralization (3.84 ± 0.02%), forming no extractable metabolite but abundant bound residues (60.9 ± 1.7%, mostly bound to humin) after 49 days of incubation. The ammonium amendment (8 mmol/kg soil) significantly inhibited the degradation (half-life of 68.0 ± 7.7 days), mineralization (2.0 ± 1.1%), and bound-residue formation (23.7 ± 0.2%). Under anoxic conditions, 4-NP111 did not degrade during 49 days of incubation and the ammonium amendment (40 mmol/kg soil) did not affect its persistence. Our results demonstrate that bound-residue formation was a major mechanism for NP dissipation in the red soil under oxic conditions and that chemical nitrogen fertilizer at average field application rate may already considerably increase NP recalcitrance in agricultural soils. -- Highlights:: • Aerobic mineralization of the nonylphenol isomer 4-NP111 in paddy red soil is minor. • Bound-residue formation is the major mechanism for aerobic NP degradation in soil. • The majority of the bound residues of NP are localized in soil humin fraction. • Amendment of soil by ammonium strongly increase the persistence of NP in oxic soil. • Amendment of soil by ammonium does not affect the recalcitrance of NP in anoxic soil. -- Formation of bound residues was the major mechanism in paddy red soil under oxic conditions for nonylphenol dissipation, which was significantly inhibited by amendment with ammonium

  14. Ecotoxicology of organofluorous compounds.

    Science.gov (United States)

    Murphy, Margaret B; Loi, Eva I H; Kwok, Karen Y; Lam, Paul K S

    2012-01-01

    Organofluorous compounds have been developed for myriad purposes in a variety of fields, including manufacturing, industry, agriculture, and medicine. The widespread use and application of these compounds has led to increasing concern about their potential ecological toxicity, particularly because of the stability of the C-F bond, which can result in chemical persistence in the environment. This chapter reviews the chemical properties and ecotoxicology of four groups of organofluorous compounds: fluorinated refrigerants and propellants, per- and polyfluorinated compounds (PFCs), fluorinated pesticides, and fluoroquinolone antibiotics. These groups vary in their environmental fate and partitioning, but each raises concern in terms of ecological risk on both the regional and global scale, particularly those compounds with long environmental half-lives. Further research on the occurrence and toxicities of many of these compounds is needed for a more comprehensive understanding of their ecological effects.

  15. Formation of ammonium sulphate in water droplets exposed to gaseous sulphur dioxide and ammonia

    Energy Technology Data Exchange (ETDEWEB)

    van den Heuvel, A.P.; Mason, B.J.

    1963-01-01

    The rate of formation of ammonium sulphate in water drops exposed to air containing known concentrations of gaseous sulphur dioxide and ammonia has been measured. The mass of sulphate formed is proportional to the product of the surface area of the drops and the time of exposure. Extrapolation of the laboratory results to the atmosphere suggests that the large condensation nuclei 0.2 micronammonium sulphate, are formed by the absorption of SO/sub 2/ and NH/sub 3/ in cloud and fog droplets.

  16. The performance of ammonium exchanged zeolite for the biodegradation of petroleum hydrocarbons migrating in soil water.

    Science.gov (United States)

    Freidman, Benjamin L; Gras, Sally L; Snape, Ian; Stevens, Geoff W; Mumford, Kathryn A

    2016-08-01

    Nitrogen deficiency has been identified as the main inhibiting factor for biodegradation of petroleum hydrocarbons in low nutrient environments. This study examines the performance of ammonium exchanged zeolite to enhance biodegradation of petroleum hydrocarbons migrating in soil water within laboratory scale flow cells. Biofilm formation and biodegradation were accelerated by the exchange of cations in soil water with ammonium in the pores of the exchanged zeolite when compared with natural zeolite flow cells. These results have implications for sequenced permeable reactive barrier design and the longevity of media performance within such barriers at petroleum hydrocarbon contaminated sites deficient in essential soil nutrients. PMID:27132074

  17. Aqueous ammonium thiocyanate solutions as refractive index-matching fluids with low density and viscosity

    CERN Document Server

    Borrero-Echeverry, Daniel

    2016-01-01

    We show that aqueous solutions of ammonium thiocyanate (NH4SCN) can be used to match the index of refraction of several transparent materials commonly used in experiments, while maintaining low viscosity and density compared to other common refractive index-matching liquids. We present empirical models for estimating the index of refraction, density, and kinematic viscosity of these solutions as a function of temperature and concentration. Finally, we summarize some of the chemical compatibility of ammonium thiocyanate with materials commonly used in apparatus.

  18. Short-term temporal variability of ammonium and urea uptake by Alexandrium catenella (Dinophyta) in cultures

    OpenAIRE

    Jauzein, Cecile; Collos, Yves; Garces, E.; Vila, M.; Maso, M

    2008-01-01

    In batch cultures of four Mediterranean strains (from France, Italy, and Spain) of Alexandrium catenella (Whedon et Kof.) Balech growing on a daily light cycle, ammonium and urea uptake were estimated by the N-15 tracer technique. Ammonium uptake could be described by Michaelis-Menten kinetics along a substrate gradient of 0.1-10 mu gat N.L-1 for the four strains, while two different patterns were observed for urea uptake with Michaelis-Menten kinetics for one strain and linear kinetics for t...

  19. Modeling conversion of ammonium diuranate (ADU) into uranium dioxide (UO2) powder

    Science.gov (United States)

    Hung, Nguyen Trong; Thuan, Le Ba; Khoai, Do Van; Lee, Jin-Young; Jyothi, Rajesh Kumar

    2016-10-01

    In the paper, Brandon mathematical model that describes the relationship between the essential fabrication parameters [reduction temperature (TR), calcination temperature (TC), calcination time (tC) and reduction time (tR)] and specific surface area of ammonium diuranate (ADU)-derived UO2 powder products was established. The proposed models can be used to predict and control the specific surface area of UO2 powders prepared through ADU route. Suitable temperatures for conversion of ADU and ammonium uranyl carbonate (AUC) was examined with the proposed model through assessment of the sinterability of UO2 powders.

  20. AMMONIUM TREATMENT OF NATURAL CLINOPTILOLITE AND ITS CHARACTER OF ION—EXCHANGE

    Institute of Scientific and Technical Information of China (English)

    LiuYifan; WangYuying

    1998-01-01

    Ammonium can change the type of natural clinoptilolite from Jinyun of Zhejiang Province of China.The character of exchange and selectivity of ammonium type clinoptilolite to the alkali and alkaline-earth metal were investigated,the heatresistance and nitric acid-resistance of natural clinoptilolite were discussed.All types of clinoptilolite were researched by means of X-ray,IR spectroscopy,DTA analyses.The ion exchange was experimented by column operation,indicating that the valid amount of exchange capacity of NH4+ type clinoptiloties is more than 25mg/g.

  1. Inactivation of ANAMMOX communities under concurrent operation of anaerobic ammonium oxidation (ANAMMOX) and denitrification

    DEFF Research Database (Denmark)

    Chamchoi, N.; Nitisoravut, S.; Schmidt, Jens Ejbye

    2008-01-01

    A concurrent operation of anaerobic ammonium oxidation (ANAMMOX) and denitrification was investigated in a well known UASB reactor seeding with both ANAMMOX and anaerobic granular sludges. ANAMMOX activity was confirmed by hydroxylamine test and the hybridization of biomass using the gene probes...... of Amx 820 and EUB 338 mixed. Denitrification was observed through the reductions of both COD and nitrate–nitrite concentrations under anaerobic/anoxic conditions. By providing a stoichiometric ratio of nitrite to ammonium nitrogen with addition nitrate nitrogen, a gradual reduction of ANAMMOX activity...

  2. Development of miniaturized potentiometric nitrate- and ammonium selective electrodes for applications in water monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, J.; Kaden, H. [Kurt-Schwabe-Institut fuer Mess- und Sensortechnik e.V., Meinsberg (Germany); Pausch, G. [Umwelt- und Ingenieurtechnik GmbH, Dresden (Germany)

    2000-06-01

    Mobile analysis with potentiometric sensors is well suited for field measurements. Ion-selective electrodes (ISE) based on polymeric membranes for in-situ determination of nitrate and ammonium contents in ground water, drinking water and surface water have been developed. The ISE are integrated in a multisensor module (MSM) for monitoring these ions over longer time intervals. The receptor is a PVC-membrane with tridodecylammonium nitrate (TDDA) for nitrate- and nonactine for ammonium-electrodes as ionophores. As plasticizer dibutylphthalate (DBT) was used. The main parameters for assessing the efficiency of these ISE are presented. (orig.)

  3. Excretion of ammonium by a nifL mutant of Azotobacter vinelandii fixing nitrogen.

    OpenAIRE

    Bali, A.; Blanco, G.; Hill, S.; Kennedy, C

    1992-01-01

    A mutation in the gene upstream of nifA in Azotobacter vinelandii was introduced into the chromosome to replace the corresponding wild-type region. The resulting mutant, MV376, produced nitrogenase constitutively in the presence of 15 mM ammonium. When introduced into a nifH-lacZ fusion strain, the mutation permitted beta-galactosidase production in the presence of ammonium. The gene upstream of nifA is therefore designated nifL because of its similarity to the Klebsiella pneumoniae nifL gene...

  4. Fixed Ammonium in Major Types of Paddy Soils in Hunan Province,China

    Institute of Scientific and Technical Information of China (English)

    ZHANG YANGZHU; LIAO JIPEI; SUN YUHUAN; FENG YUEHUA; HUANG YUNXIANG

    2003-01-01

    The contents, affecting factors, seasonal changes and availability of fixed ammonium in major types ofpaddy soils derived from different parent materials in Hunan Province, China, were studied using the Silva-Bremner method by laboratory and pot experiments. Results showed that the content of fixed ammoniumin the plough horizons ranged from 88.3 mg kg-1 to 388.1 mg kg-1, with 273.2 ± 77.7 mg kg-1 on average,accounting for 11.2% of total soil N on average. Content of fixed ammonium decreased in the order of newlylacustrine clayey paddy soil > alluvial sandy paddy soil > purple clayey paddy soil > newly alluvial sandypaddy soil > yellow clayey paddy soil > reddish-yellow clayey paddy soil > granitic sandy paddy soil. Therewere four distribution patterns of fixed ammonium in the profiles to 1-m depth, i.e., increase with the depth,decrease with increasing depth, no distinct change with the depth, and abrupt increase or decrease in somehorizon. Percentage of fixed ammonium in total N increased with the depth in most of the soils. Fixationof NH4+ by soil was higher at 30 ℃ than at 20 ℃ and 40 ℃, and continuous submergence benefited thefixation of NH4+ in newly alluvial sandy paddy soil, purple clayey paddy soil and alluvial sandy paddy soil,while alternating wetting and drying contributed to the fixation of NH4+ in yellow clayey paddy soil mostly.Fixed ammonium content in the test paddy soils was significantly correlated with < 0.01 mm clay content(P < 0.05), but not with < 0.001 mm clay content, total N, organic N and organic matter. Fixed ammoniumcontent varied with rice growth stages. Application of N fertilizer promoted fixation of NH4+ by soil, and Nuptake by rice plant promoted release of fixed ammonium from the soil. Recently fixed ammonium in paddysoil after N fertilizer application was nearly 100% available to rice plant, while native fixed ammonium wasonly partly available, varying with the soil type and rice type.

  5. Antioxidant Potential of Momordica Charantia in Ammonium Chloride-Induced Hyperammonemic Rats

    OpenAIRE

    A. Justin Thenmozhi; Subramanian, P.

    2011-01-01

    The present study was aimed to investigate the antioxidant potential of Momordica charantia fruit extract (MCE) in ammonium chloride-induced (AC) hyperammonemic rats. Experimental hyperammonemia was induced in adult male Wistar rats (180–200 g) by intraperitoneal injections of ammonium chloride (100 mg kg−1 body weight) thrice a week. The effect of oral administration (thrice a week for 8 consecutive weeks) of MCE (300 mg kg−1 body weight) on blood ammonia, plasma urea, serum liver marker enz...

  6. Modification of a Brazilian smectite clay with different quaternary ammonium salts

    Directory of Open Access Journals (Sweden)

    Maria Flávia Delbem

    2010-01-01

    Full Text Available In this work, a smectite clay from the State of Paraiba, Brazil, was treated with six different types of ammonium salts, which is an usual method to enhance the affinity between the clay and polymer for the preparation of nanocomposites. The clays, before and after modification, were characterized by X ray diffraction. The conformation of the salts within the platelets of the clay depended on the number of long alkyl chains of the salt. The thermal stability of the clays was also studied. The ammonium salts thermal decomposition was explained in light of their position within the organoclays.

  7. Synthesis and crystal structure of double ammonium and terbium sulfate (MHΛ4)Λ6TbΛ4(SOΛ4)Λ9x2HΛ2O

    International Nuclear Information System (INIS)

    Double ammonium and RE sulfates of the composition NH4Ln(SO4)2xH2O for Ln=Gd, Ho, Yb and Lu and (NH4)6Ln4(SO4)9x2H2O for Ln=Tb, Dy and Er were produced by the isothermal evaporation from solutions at 80-95 deg C. (NH4)6Th4(SO4)9x2H2O crystals are referred to the monoclinic crystal system. Lattice parameters are equal to: a=9.008 (5), b=18.323(8), c=21.39(1) A, β=95.33(5)deg, Z=4 Atom coordinates, interaeltomic distances, valent angs are given. Compound structure represents a framework composed of Tl-polyhedrons of two types and SO4-tetrahedrons. Non-equivalence of crystallochemical functions of NH4-group in (NH4)6Tb4(SO4)9x2H2O structure is revealed. It is shown that in terms of the composition of stable double sulfates ammonium salts have the strongest resemblance with potassium salts

  8. Surface Functionalization of Polyethersulfone Membrane with Quaternary Ammonium Salts for Contact-Active Antibacterial and Anti-Biofouling Properties

    Directory of Open Access Journals (Sweden)

    Xiao Hu

    2016-05-01

    Full Text Available Biofilm is a significant cause for membrane fouling. Antibacterial-coated surfaces can inhibit biofilm formation by killing bacteria. In this study, polyethersulfone (PES microfiltration membrane was photografted by four antibiotic quaternary ammonium compounds (QACs separately, which were synthesized from dimethylaminoethyl methacrylate (DMAEMA by quaternization with butyl bromide (BB, octyl bromide (OB, dodecyl bromide (DB, or hexadecyl bromide (HB. XPS, ATR-FTIR, and SEM were used to confirm the surfaces’ composition and morphology. After modification, the pores on PES-g-DMAEMA-BB and PES-g-DMAEMA-OB were blocked, while PES-g-DMAEMA-DB and PES-g-DMAEMA-HB were retained. We supposed that DMAEMA-BB and DMAEMA-OB aggregated on the membrane surface due to the activities of intermolecular or intramolecular hydrogen bonds. Bacteria testing found the antibacterial activities of the membranes increased with the length of the substituted alkyl chain. Correspondingly, little bacteria were observed on PES-g-DMAEMA-DB and PES-g-DMAEMA-HB by SEM. The antifouling properties were investigated by filtration of a solution of Escherichia coli. Compared with the initial membrane, PES-g-DMAEMA-DB and PES-g-DMAEMA-HB showed excellent anti-biofouling performance with higher relative flux recovery (RFR of 88.3% and 92.7%, respectively. Thus, surface functionalization of the PES membrane with QACs can prevent bacteria adhesion and improve the anti-biofouling activity by the contact-active antibacterial property.

  9. Removal of ammonium chloride generated by ammonia slip from the SNCR process in municipal solid waste incinerators.

    Science.gov (United States)

    Hwang, In-Hee; Minoya, Hiroshi; Matsuto, Toshihiko; Matsuo, Takayuki; Matsumoto, Akihiro; Sameshima, Ryoji

    2009-03-01

    The selective non-catalytic reduction (SNCR) process is one of the methods used to reduce NO(x) to N(2) and H(2)O by injecting NH(3) or urea solution into a high-temperature furnace. Merits of this method include simple handling, low cost, and energy savings. However, a critical problem of the SNCR process is the generation of ammonia slip; in reactions with HCl in flue gas, ammonium chloride is generated and forms detached white plumes near the stack. Using a laboratory-scale experimental apparatus, we examined the possibility of NH(4)Cl collection and removal by a bag filter (BF). The molar NH(3)/HCl ratio of the compound collected at the filter was nearly one, regardless of gas temperature, retention time, and concentration, confirming the formation of NH(4)Cl. The NH(4)Cl generation ratio increased as reaction temperature decreased, indicating that the collection efficiency of NH(4)Cl should increase if the BF is operated at the lowest possible temperature while avoiding the critical point causing low-temperature corrosion (e.g., 150 degrees C). In addition, the use of activated carbon injection in the front of the BF and the dust layer on the BF are expected to capture slipped ammonia at the BF and reduce NH(4)Cl fume generation in the stack.

  10. IUPAC-NIST Solubility Data Series. 85. Transition and 12-14 Main Group Metals, Lanthanide, Actinide, and Ammonium Halates

    Science.gov (United States)

    Miyamoto, Hiroshi

    2008-06-01

    This paper is the fourth and final volume in the halate solubility series. The solubility data for halates of transition metals, lanthanides, actinides, ammonium, and metallic elements of the main groups 12-14 are reviewed. Where appropriate, binary, ternary, and multicomponent systems are critically evaluated. Most of the solubility results were obtained in water or aqueous solutions of electrolytes. The solubility in organic solvents and aqueous-organic solvent mixtures is also collected in this volume. All these data were critically examined for their reliability. The best values were selected on the basis of critical evaluations and presented in tabular form. Fitting equations and graphical plots are also provided. When numerical data were not reported in an original publication, they were read out from figures and digitized by the compilers. The quantities, units, and symbols used in this volume are in accord with IUPAC recommendations. We always reported the original data and, if necessary, transferred them into the IUPAC recommended units and symbols. The literature on the solubility data was researched through 2002. The halates of these metals play a role in industrial processes. For example, some halates are essential as catalysts, heat stabilizers, and blanching reagents for manufacturing polymer products such as textiles and resins. Some iodates are used in pyrotechnic compounds for weather modification and colored smoke generation. The nonlinear halate crystals are important in construction of optical devices.

  11. Dose- (and time-) dependent blockade of pregnancy in Sprague-Dawley rats administered ammonium dinitramide in drinking water.

    Science.gov (United States)

    Kinkead, E R; Wolfe, R E; Feldmann, M L

    1996-01-01

    Ammonium dinitramide (ADN) is a class 1.1 explosive oxidizer that can be used in solid rocket propellant mixtures and explosives. A 90-day general toxicity/ reproductive screen performed on this compound at doses of 162, 103, 29, and 0.0 mg ADN/kg/day resulted in a treatment-related adverse effect on litter production. Incidences of animals producing litters (1/11, 3/12, 12/12, and 11/12, respectively) and mean numbers of pups per litter (7, 7, 16, and 15, respectively) both were statistically significantly less than controls. In a follow-up study, mated dams treated with ADN at the same doses and examined at gestation days (GDs) 10 and 20 showed an effect in fetus loss similar to that seen in the reproductive screen. A pre- versus postimplantation dosing regimen indicated that implantation is vulnerable to ADN effects during the preimplantation period (GDs 1-3). No implantation sites were found in the rats treated with 2000 mg ADN/L drinking water (target dose of 160 mg ADN/kg/day) during GDs 1-3. Numbers of implantation sites found in the rats treated during GDs 4-8 were similar to those found in the control group. The pituitary was not identified specifically in this study as the site of primary action, but serum progesterone was reduced by 27%, which may have resulted in reduced fertility. PMID:8713714

  12. Novel 1,3-dipolar cycloadditions of dinitraminic acid: implications for the chemical stability of ammonium dinitramide.

    Science.gov (United States)

    Rahm, Martin; Brinck, Tore

    2008-03-20

    Density functional theory at the B3LYP/6-31+G(d,p) level and ab initio calculations at the CBS-QB3 level have been used to analyze 1,3 dipolar cycloaddition reactions of dinitraminic acid (HDN) and its proton transfer isomer (HO(O)NNNO2). It is shown that the nitro group of HDN and the -N-N=O functionality of the isomer react readily with carbon-carbon double bonds. Cycloadditions of HDN are compared with the corresponding reactions with azides and nitrile oxides as 1,3 dipoles. It is shown that the reactivities of HDN and its proton transfer isomer decrease with increasing electron withdrawing power of the substituents adjacent to the carbon-carbon double bond. In contrast, for azides and nitrile oxides, the highest reactivity is obtained with dipolarophiles with strongly electron withdrawing substituents. The observed reactivity trends allow for the design of unsaturated compounds that are highly reactive toward azides and chemically inert toward dinitramides. This may be of relevance for the development of binder materials for ammonium dinitramide based propellants. PMID:18278886

  13. Crystal structure of ammonium dioxo(2-hydroxynaphthaldehydesemicarbazonato)-vanadate (5)

    Energy Technology Data Exchange (ETDEWEB)

    Kravtsov, V.Kh.; Belyaeva, K.F.; Biyushkin, V.N.; Struchkov, Yu.T.; Bodyu, V.G.; Samus, N.M. (AN Moldavskoj SSR, Kishinev. Inst. Prikladnoj Fiziki; AN SSSR, Moscow. Inst. Ehlementoorganicheskikh Soedinenij; Kishinevskij Gosudarstvennyj Univ. (USSR))

    1981-01-01

    During the interaction of VOSO/sub 4/x3H/sub 2/O with semicarbazone of 2-hydroxynaphthaldehyde (2-Nafsc) the fixation of air oxygen takes place with the formation of diamagnetic compound NH/sub 4/(VO/sub 2/(2-Nafsc-2H) (1). The structure 1 is established using the method of X-ray structural analysis. Crystals 1 are monoclinic: a=13.930(2), b=16.097(3), c=6.267(1)A, ..gamma..=111.12(2)deg, Z=4, sp. gr. B2. In the complex anion V atom has a distorted tetragonal-pyramid coordination. One of two oxo-ligands (V-O 1.609(3)A) is in apical position, four coordination vacancies in the pyramid base are occupied by the other oxo-ligand (V-O 1.654(3)A, by O and N atoms of semicarbazide fragment (V-O and V-N 1.974(2) and 2.127(2)A respectively) and O atom (V-O 1.861(3)A) of aldehyde hydroxy group.

  14. Nitrate Remediation of Soil and Groundwater Using Phytoremediation: Transfer of Nitrogen Containing Compounds from the Subsurface to Surface Vegetation

    Science.gov (United States)

    Nelson, Sheldon

    2013-04-01

    Nitrate Remediation of Soil and Groundwater Using Phytoremediation: Transfer of Nitrogen Containing Compounds from the Subsurface to Surface Vegetation Sheldon Nelson Chevron Energy Technology Company 6001 Bollinger Canyon Road San Ramon, California 94583 snne@chevron.com The basic concept of using a plant-based remedial approach (phytoremediation) for nitrogen containing compounds is the incorporation and transformation of the inorganic nitrogen from the soil and/or groundwater (nitrate, ammonium) into plant biomass, thereby removing the constituent from the subsurface. There is a general preference in many plants for the ammonium nitrogen form during the early growth stage, with the uptake and accumulation of nitrate often increasing as the plant matures. The synthesis process refers to the variety of biochemical mechanisms that use ammonium or nitrate compounds to primarily form plant proteins, and to a lesser extent other nitrogen containing organic compounds. The shallow soil at the former warehouse facility test site is impacted primarily by elevated concentrations of nitrate, with a minimal presence of ammonium. Dissolved nitrate (NO3-) is the primary dissolved nitrogen compound in on-site groundwater, historically reaching concentrations of 1000 mg/L. The initial phases of the project consisted of the installation of approximately 1750 trees, planted in 10-foot centers in the areas impacted by nitrate and ammonia in the shallow soil and groundwater. As of the most recent groundwater analytical data, dissolved nitrate reductions of 40% to 96% have been observed in monitor wells located both within, and immediately downgradient of the planted area. In summary, an evaluation of time series groundwater analytical data from the initial planted groves suggests that the trees are an effective means of transfering nitrogen compounds from the subsurface to overlying vegetation. The mechanism of concentration reduction may be the uptake of residual nitrate from the

  15. Production of high purity uranium compounds from crude yellow cake

    International Nuclear Information System (INIS)

    High purity ammonium uranyl tricarbonate is produced from crude plant yellow cake by treatment of the yellow cake with a mineral acid, neutralization of the acidic solution with a conversion of the uranium therein to ammonium uranyl tricarbonate, precipitation of the ammonium uranyl tricarbonate with a nonsolvent, followed by separation. Optionally, the ammonium uranyl tricarbonate can be calcined to produce high purity uranium oxides

  16. NATURAL POLYACETYLENE COMPOUNDS

    OpenAIRE

    D. A. Konovalov

    2014-01-01

    Polyacetylenes (polyynes) are compounds which contain two or more triple bonds in its structure. About 2 000 different polyacetylenes and biogenetically related substances were identified in 24 families of higher plants. However, most of these compounds were found in seven families of flowering plants: Apiaceae (Umbelliferae), Araliaceae, Asteraceae (Compositae), Campanulaceae, Olacaceae, Pittosporaceae and Santalaceae. Polyacetylenes are relatively unstable, chemically and biologically activ...

  17. NATURAL POLYACETYLENE COMPOUNDS

    Directory of Open Access Journals (Sweden)

    D. A. Konovalov

    2014-01-01

    Full Text Available Polyacetylenes (polyynes are compounds which contain two or more triple bonds in its structure. About 2 000 different polyacetylenes and biogenetically related substances were identified in 24 families of higher plants. However, most of these compounds were found in seven families of flowering plants: Apiaceae (Umbelliferae, Araliaceae, Asteraceae (Compositae, Campanulaceae, Olacaceae, Pittosporaceae and Santalaceae. Polyacetylenes are relatively unstable, chemically and biologically active compounds, and present in fungi, microorganisms, marine invertebrates and other organisms except for plants. Acetylenes form distinct specialized group of chemically active natural compounds, which are biosynthesized in plants of unsaturated fatty acids. In addition to widespread aliphatic polyacetylenes thiophenes dithiacyclohexadienes (thiarubrines, thioethers, sulphoxides, sulphones, alkamides, chlorohydrins, lactones, spiroacetal enol ethers, furans, pyrans, tetrahydropyrans, isocoumarins, aromatic acetylenes were also found in plant species. Polyacetylenes are localized in different plant organs, and can be found both individually and as a compound with carbohydrates, terpene, phenolic and other compounds. Many polyacetylenes are found in the composition of the essential oils of plants and it confirms their strongly marked ecological functions. From biological point of view these compounds are often synthesized by plants as toxic or bitter antifeedants, allelopathic compounds, phytoalexins or broadly antibiotic components. Polyynes are strong photosensitizers. They exhibit anti-inflammatory, anti-coagulant, anti-bacterial, antituberculosis, anti-fungal, anti-viral, neuroprotective and neurotoxic activity. Immunostimulatory influence associated with certain allergenicity of some of these substances was established. Therefore, without a doubt polyacetylenes are of interest for the modern pharmacy and medicine.

  18. Stable isotopes labelled compounds

    International Nuclear Information System (INIS)

    The catalogue on stable isotopes labelled compounds offers deuterium, nitrogen-15, and multiply labelled compounds. It includes: (1) conditions of sale and delivery, (2) the application of stable isotopes, (3) technical information, (4) product specifications, and (5) the complete delivery programme

  19. 40 CFR 721.6183 - Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow alkyl amines...

    Science.gov (United States)

    2010-07-01

    ... - maleic anhydride polymer and hydrogenated tallow alkyl amines, sodium salts, compds. with ethanolamine... Substances § 721.6183 Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow... subject to reporting. (1) The chemical substance identified as amides, from ammonium hydroxide -...

  20. Growth at low ammonium concentrations and starvation response as potential factors involved in niche differentiation among ammonia-oxidizing bacteria

    NARCIS (Netherlands)

    Bollmann, A.; Bär-Gilissen, M.J.; Laanbroek, H.J.

    2002-01-01

    In nature, ammonia-oxidizing bacteria have to compete with heterotrophic bacteria and plants for limiting amounts of ammonium. Previous laboratory experiments conducted with Nitrosomonas europaea suggested that ammonia-oxidizing bacteria are weak competitors for ammonium. To obtain a better insight

  1. The integration of methanogenesis with denitrification and anaerobic ammonium oxidation in an expanded granular sludge bed reactor

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The integration of methanogenesis with denitrification and anaerobic ammonium oxidation(ANAMMOX) was studied in an expanded granular sludge bed(EGSB) reactor in this work. Experimental results from the continuous treatment of wastewater with nitrite and ammonium, which lasted for 107 days, demonstrated that wastewater with high nitrite and ammonium could be anaerobically treated in an expanded granular sludge bed reactor. More than 91% to 97% of COD were removed at up to about 3.9 g COD/(L@d) of COD volumetric loading rate. More than 97% to 100% of nitrite was denitrified at up to about 0.8g NO2-N/(L@d), which is 16 times higher than that in a conventional activated sludge system with nitrification/denitrification(0.05g N/((L@d). No dissimilatory reduction of nitrite to ammonium occurred in the process. However, maximum of about 40% ammonium was found to be lost. Batch tests of 15 days with sludge from the reactor showed that 100% of nitrite was denitrified completely, and about 3% of ammonium was removed when only ammonium (34.3 mg/L) and nitrite(34.3 mg/L) were added into the sludge suspension medium. Furthermore, about 15% of ammonium amounts were lost with organic COD addition. It suggested that the methanogenesis in the system could enhance ANAMMOX because of intermediate hydrogen produced during methanogenesis.

  2. Aerobic physiology of redox-engineered Saccharomyces cerevisiae strains modified in the ammonium assimilation for increased NADPH availability

    DEFF Research Database (Denmark)

    Santos, Maria Margarida M. dos; Thygesen, G.; Kotter, P.;

    2003-01-01

    Recombinant strains altered in the ammonium assimilation pathways were constructed with the purpose of increasing NADPH availability. The NADPH-dependent glutamate dehydrogenase encoded by GDH1, which accounts for a major fraction of the NADPH consumption during growth on ammonium, was deleted, a...

  3. Oxidative desulfurization of diesel fuel using amphiphilic quaternary ammonium phosphomolybdate catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Jianghua; Wang, Guanghui; Zeng, Danlin; Tang, Yan [College of Chemical Engineering and Technology, Wuhan University of Science and Technology, Wuhan 430081 (China); Wang, Meng; Li, Yanjun [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China)

    2009-12-15

    Phosphomolybdic acid (HPMo) modified respectively with tetramethyl ammonium chloride (TMAC), dodecyl trimethyl ammonium chloride (DTAC) and hexadecyl trimethyl ammonium chloride (HTAC) as the catalysts were prepared and characterized by FT-IR, XRD and SEM. The catalysts were evaluated for the oxidative desulfurization of benzothiophene (BT), dibenzothiophene (DBT) and straight-run diesel using hydrogen peroxide as an oxidant. Results show that all of the catalysts keep the Keggin structures and are finely dispersed with mixing of quaternary ammonium salts. Hexadecyl chains are more favorable to wrap up DBT to the catalytic center and form stable emulsion system with higher conversion rates of DBT. The shorter dodecyl chains can wrap up BT more suitably and bring smaller steric hindrance, which display higher conversion rates of BT. The oxidative reactions fit apparent first-order kinetics, and the apparent activation energies of DBT are much lower than those of BT. The desulfurization rate of straight-run diesel can be up to 84.4% with the recovery rate of 98.1% catalyzed by [HPMo][HTAC]{sub 2} in 2 h. When increasing the extraction times, the desulfurization rates increase, but the recovery rates of diesel decrease significantly. (author)

  4. Deciphering the molecular basis of ammonium uptake and transport in maritime pine.

    Science.gov (United States)

    Castro-Rodríguez, Vanessa; Assaf-Casals, Iman; Pérez-Tienda, Jacob; Fan, Xiaorong; Avila, Concepción; Miller, Anthony; Cánovas, Francisco M

    2016-08-01

    Ammonium is the predominant form of inorganic nitrogen in the soil of coniferous forests. Despite the ecological and economic importance of conifers, the molecular basis of ammonium uptake and transport in this group of gymnosperms is largely unknown. In this study, we describe the functional characterization of members of the AMT gene family in Pinus pinaster: PpAMT1.1, PpAMT1.2 and PpAMT1.3 (subfamily 1) and PpAMT2.1 and PpAMT2.3 (subfamily 2). Our phylogenetic analysis indicates that in conifers, all members of the AMT1 subfamily evolved from a common ancestor that is evolutionarily related to the ancient PpAMT1.2 gene. Individual AMT genes are developmentally and nutritionally regulated, and their transcripts are specifically distributed in different organs. PpAMT1.3 was predominantly expressed in the roots, particularly during N starvation and mycorrhizal interaction, whereas PpAMT2.3 was preferentially expressed in lateral roots. Immunolocalization studies of roots with varied nitrogen availability revealed that PpAMT1 and PpAMT2 proteins play complementary roles in the uptake of external ammonium. Heterologous expression in yeast and Xenopus oocytes revealed that the AMT genes encode functional transporters with different kinetics and with different capacities for ammonium transport. Our results provide new insights on how nitrogen is acquired and transported in conifers. PMID:26662862

  5. Winter Wheat and Maize Response to Urea Ammonium Nitrate and a New Urea Formaldehyde Polymer Fertilizer

    Science.gov (United States)

    Slow release nitrogen (N) fertilizers have potential to improve yield and nitrogen use efficiency (NUE) in winter wheat (Triticum aestivum L.) and maize (Zea mays L.). A slow release urea formaldehyde polymer (UFP) was compared with conventional aqueous urea-ammonium nitrate (UAN) [(NH2)2CO, NH4NO3]...

  6. High levan production by Bacillus licheniformis NS032 using ammonium chloride as the sole nitrogen source.

    Science.gov (United States)

    Kekez, B D; Gojgic-Cvijovic, G D; Jakovljevic, D M; Stefanovic Kojic, J R; Markovic, M D; Beskoski, V P; Vrvic, M M

    2015-03-01

    In this study, levan production by Bacillus licheniformis NS032 isolated from a petroleum sludge sample was investigated. High levan yield was obtained in a wide range of sucrose concentrations (up to 400 g/L) and, contrary to most levan-producing strains, using ammonium chloride as the sole N source. Interaction between sucrose, ammonium chloride, and initial pH of the medium in a low sucrose (60-200 g/L) and a high sucrose (300-400 g/L) system was analyzed by response surface methodology. According to the calculated model in the low sucrose system, maximum predicted levan yield was 47.8 g/L (sucrose 196.8 g/L, ammonium chloride 2.4 g/L, pH 7.0), while in the high sucrose system, levan yield was 99.2 g/L (sucrose 397.6 g/L, ammonium chloride 4.6 g/L, pH 7.4). In addition, protective effect of microbial levan against copper toxicity to Daphnia magna is observed for the first time. The acute toxicity (48 h EC50) of copper decreased from 0.14 to 0.44 mg/L by levan in concentration of 50 ppm. PMID:25592434

  7. Iodine catalyzed and tertiary butyl ammonium bromide promoted p reparation of b enzoxazaphosphininyl phenylboronates

    Directory of Open Access Journals (Sweden)

    K. R. Kishore K. Reddy,

    2009-05-01

    Full Text Available Benzoxazaphosphininyl Phenylboronates were prepared by O-Phosphorylation of potassium salt ofphenylboronic acid with cyclic phosphoromonochloridates in the presence of stoichiometric amount of Iodineand catalytic amount of tertiary butyl ammonium bromide at 50-60 °C in dry toluene.

  8. Thermodynamic Analysis of Allosteric and Chelate Cooperativity in Di- and Trivalent Ammonium/Crown-Ether Pseudorotaxanes.

    Science.gov (United States)

    Nowosinski, Karol; von Krbek, Larissa K S; Traulsen, Nora L; Schalley, Christoph A

    2015-10-16

    A detailed thermodynamic analysis of the axle-wheel binding in di- and trivalent secondary ammonium/[24]crown-8 pseudorotaxanes is presented. Isothermal titration calorimetry (ITC) data and double mutant cycle analyses reveal an interesting interplay of positive as well as negative allosteric and positive chelate cooperativity thus providing profound insight into the effects governing multivalent binding in these pseudorotaxanes.

  9. Phosphate and ammonium sorption capacity of biochar and hydrochar from different wastes.

    Science.gov (United States)

    Takaya, C A; Fletcher, L A; Singh, S; Anyikude, K U; Ross, A B

    2016-02-01

    The potential for biochar and hydrochar to adsorb phosphate and ammonium is important for understanding the influence of these materials when added to soils, compost or other high nutrient containing environments. The influence of physicochemical properties such as mineral content, surface functionality, pH and cation exchange capacity has been investigated for a range of biochars and hydrochars produced from waste-derived biomass feedstocks. Hydrochars produced from hydrothermal carbonisation at 250 °C have been compared to low and high temperature pyrolysis chars produced at 400-450 °C and 600-650 °C respectively for oak wood, presscake from anaerobic digestate (AD), treated municipal waste and greenhouse waste. In spite of differences in char physicochemical properties and processing conditions, PO4-P and NH4-N sorption capacities ranged from about 0 to 30 mg g(-1) and 105.8-146.4 mg g(-1) respectively. Chars with high surface areas did not possess better ammonium adsorption capacities than low surface area chars, which suggests that surface area is not the most important factor influencing char ammonium adsorption capacity, while char calcium and magnesium contents may influence phosphate adsorption. Desorption experiments only released a small fraction of adsorbed ammonium or phosphate (<5 mg g(-1) and a maximum of 8.5 mg g(-1) respectively). PMID:26702555

  10. Lessons to be learned from an analysis of ammonium nitrate disasters in the last 100 years

    International Nuclear Information System (INIS)

    Highlights: • Root causes and contributing factors from ammonium nitrate incidents are categorized into 10 lessons. • The lessons learned from the past 100 years of ammonium nitrate incidents can be used to improve design, operation, and maintenance procedures. • Improving organizational memory to help improve safety performance. • Combating and changing organizational cultures. - Abstract: Process safety, as well as the safe storage and transportation of hazardous or reactive chemicals, has been a topic of increasing interest in the last few decades. The increased interest in improving the safety of operations has been driven largely by a series of recent catastrophes that have occurred in the United States and the rest of the world. A continuous review of past incidents and disasters to look for common causes and lessons is an essential component to any process safety and loss prevention program. While analyzing the causes of an accident cannot prevent that accident from occurring, learning from it can help to prevent future incidents. The objective of this article is to review a selection of major incidents involving ammonium nitrate in the last century to identify common causes and lessons that can be gleaned from these incidents in the hopes of preventing future disasters. Ammonium nitrate has been involved in dozens of major incidents in the last century, so a subset of major incidents were chosen for discussion for the sake of brevity. Twelve incidents are reviewed and ten lessons from these incidents are discussed

  11. Epoxidation of Alkenes with Aqueous Hydrogen Peroxide and Quaternary Ammonium Bicarbonate Catalysts

    DEFF Research Database (Denmark)

    Mielby, Jerrik Jørgen; Kegnæs, Søren

    2013-01-01

    A range of solid and liquid catalysts containing bicarbonate anions were synthesised and tested for the epoxidation of alkenes with aqueous hydrogen peroxide. The combination of bicarbonate anions and quaternary ammonium cations opens up for new catalytic systems that can help to overcome challen...

  12. Mechanisms of ammonium assimilation by Chlorella vulgaris F1068: Isotope fractionation and proteomic approaches.

    Science.gov (United States)

    Liu, Na; Li, Feng; Ge, Fei; Tao, Nengguo; Zhou, Qiongzhi; Wong, Minghung

    2015-08-01

    Removal of ammonium (NH4(+)-N) by microalgae has evoked interest in wastewater treatment, however, the detailed mechanisms of ammonium assimilation remain mysterious. This study investigated the effects of NH4(+)-N concentration on the removal and biotransformation efficiency by Chlorella vulgaris F1068, and explored the mechanisms by (15)N isotope fractionation and proteome approaches. The results showed NH4(+)-N was efficiently removed (84.8%) by F1068 at 10mgL(-1) of NH4(+)-N. The isotope enrichment factor (ε=-2.37±0.08‰) of (15)N isotope fractionation revealed 47.6% biotransformation at above condition, while 7.0% biotransformation at 4mgL(-1) of NH4(+)-N (ε=-1.63±0.06‰). This was due to the different expression of glutamine synthetase, a key enzyme in ammonium assimilation, which was up-regulated 6.4-fold at proteome level and 18.0-fold at transcription level. The results will provide a better mechanistic understanding of ammonium assimilation by microalgae and this green technology is expected to reduce the burden of NH4(+)-N removal for municipal sewage treatment plants. PMID:25965256

  13. Fluorometric determination of ammonium ion by ion chromatography using postcolumn derivatization with o-phthaldialdehyde.

    Science.gov (United States)

    Kuo, Chun-Ting; Wang, Po-Yen; Wu, Chien-Hou

    2005-08-26

    A postcolumn fluorometric derivatization method for the determination of trace amounts of ammonium ion (microg/L level) under matrices with high concentrations of sodium and amino acids has been developed. In this method, ammonium ion was determined by ion chromatography combined with fluorometric detection (IC-FL) in less than 16 min. IC was performed in a high-capacity cation-exchange Dionex IonPac CS16 analytical column (250 mm x 5 mm) under isocratic conditions with 30 mM methanesulfonic acid (MSA) as mobile phase at flow-rate 1.0 mL/min. To remove amino acid interference, the postcolumn derivatization based on the reaction of ammonia with o-phthaldialdehyde (OPA) and sulfite was applied. The excitation and emission wavelengths were 364 and 425 nm, respectively. The effects of pH, reaction temperature and time, OPA-reagent composition and concentration, and sample matrix were studied. The linear range and detection limit of this method were similar to the standard method. The IC-FL method with a postcolumn fluorometric derivatization allows the routine determination of ammonium ion in extreme matrices where the ratios of sodium and amino acids to ammonium are up to 2,800,000:1 and 28,000:1, respectively. PMID:16106853

  14. Temperature dependence of crystals conductivity both potassium sulfates and ammonium sulfates

    International Nuclear Information System (INIS)

    In the work the results of temperature dependence of conductivity of crystals both potassium sulfate and ammonium sulfate are given. The superficial specific conductivity and its dependence on width of a backlash between the central and ring electrodes are determined. (author)

  15. 75 FR 41725 - Food Additives Permitted in Feed and Drinking Water of Animals; Ammonium Formate

    Science.gov (United States)

    2010-07-19

    ... Additives Permitted in Feed and Drinking Water of Animals; Ammonium Formate AGENCY: Food and Drug... regulations for food additives permitted in feed and drinking water of animals to provide for the safe use of... Part 573 Animal feeds, Food additives. 0 Therefore, under the Federal Food, Drug, and Cosmetic Act...

  16. 78 FR 42692 - Food Additives Permitted in Feed and Drinking Water of Animals; Ammonium Formate

    Science.gov (United States)

    2013-07-17

    ... additives permitted in feed and drinking water of animals to correct the description of ammonium formate... regulations for food additives permitted in feed and drinking water of animals do not correctly describe... Part 573 Animal feeds, Food additives. Therefore, under the Federal Food, Drug, and Cosmetic Act...

  17. Vigna subterranea ammonium transporter gene (VsAMT1: Some bioinformatics insights

    Directory of Open Access Journals (Sweden)

    Adewole T. Adetunji

    2015-12-01

    Full Text Available Ammonium transporters (AMTs play a role in the uptake of ammonium, the form in which nitrogen is preferentially absorbed by plants. Vigna subterranea (VsAMT1 and Solanum tuberosum (StAMT1 AMT1s were characterized using molecular biology and bioinformatics methods. AMT1-specific primers were designed and used to amplify the AMT1 internal regions. Nucleotide sequencing, alignment and phylogenetic analysis assigned VsAMT1 and StAMT1 to the AMT1 family. The deduced amino acid sequences showed that VsAMT1 is 92% and 89% similar to Phaseolus vulgaris PvAMT1.1 and Glycine max AMT1 respectively, while StAMT1 is 92% similar to Solanum lycopersicum LeAMT1.1, and correspond to the 5th–10th trans-membrane domains. Residues VsAMT1 D23 and StAMT1 D15 are predicted to be essential for ammonium transport, while mutations of VsAMT1 W1A-L and S87A and StAMT1 S76A may further enhance ammonium transport. In addition to nitrogen uptake from the roots, VsAMT1 may also contribute to interactions with rhizobia.

  18. Synthesis of hierarchical zeolites using an inexpensive mono-quaternary ammonium surfactant as mesoporogen.

    Science.gov (United States)

    Zhu, Xiaochun; Rohling, Roderigh; Filonenko, Georgy; Mezari, Brahim; Hofmann, Jan P; Asahina, Shunsuke; Hensen, Emiel J M

    2014-12-01

    A simple amphiphilic surfactant containing a mono-quaternary ammonium head group (N-methylpiperidine) is effective in imparting substantial mesoporosity during synthesis of SSZ-13 and ZSM-5 zeolites. Highly mesoporous SSZ-13 prepared in this manner shows greatly improved catalytic performance in the methanol-to-olefins reaction compared to bulk SSZ-13. PMID:25316609

  19. Sources, distribution, and acidity of sulfate–ammonium aerosol in the Arctic in winter–spring

    NARCIS (Netherlands)

    Fisher, J.A.; Jacob, D.J.; Wang, Q.; Bahreini, R.; Carouge, C.C.; Cubison, M.J.; Dibb, J.E.; Diehl, T.; Jiminez, J.L.; Leibensperger, E.M.; Lu, Z.; Meinders, M.B.J.; Pye, H.O.T.; Quinn, P.K.; Sharma, S.; Streets, D.G.; Donkelaar, van A.; Yantosca, R.M.

    2011-01-01

    We use GEOS-Chem chemical transport model simulations of sulfate–ammonium aerosol data from the NASA ARCTAS and NOAA ARCPAC aircraft campaigns in the North American Arctic in April 2008, together with longer-term data from surface sites, to better understand aerosol sources in the Arctic in winter–s

  20. The importance of dissimilatory nitrate reduction to ammonium (DNRA) in the nitrogen cycle of coastal ecosystems

    DEFF Research Database (Denmark)

    Giblin, Anne E.; Tobias, Craig R.; Song, Bongkeun;

    2013-01-01

    the ecosystem. However, there is a competing nitrate reduction process, dissimilatory nitrate reduction to ammonium (DNRA), that conserves N within the ecosystem. The recent application of nitrogen stable isotopes as tracers has generated growing evidence that DNRA is a major nitrogen pathway that cannot...

  1. Hydrolysis of epoxides and aziridines catalyzed by polymer-supported quarternary ammonium bisulfate

    Institute of Scientific and Technical Information of China (English)

    Wan Xuan Zhang; Kang Ye

    2008-01-01

    Macroporous resin (D201)-supported quartemary ammonium bisulfate (D201-HSO4)was prepared and effectively used in catalyzing the hydrolysis of epoxides or aziridines under mild and non-metal conditions to give the corresponding 1,2-diols and β-amino alcohols in high yields.The catalyst was facilely prepared and recyclable.

  2. Fixed Ammonium COntents and NH4+ Fixation Capacities of Some Cultivated Soils in China

    Institute of Scientific and Technical Information of China (English)

    WENQI-XIAO; CHENGLI-LI; 等

    1995-01-01

    Fixed ammonium contents and NH4+ fixation capacities of some representative cultivated solis collected from 16 provinces of China were studied.Results showed that the contents of fixed ammonium in soils ranged from 35 to 573 mg N kg-1,with an average of 198mg Nkg-1.The content of fixed ammonium correlated very significantly with mica content for tropical and subtropical soils,whereas this was not the case for soils in the temperate zone.At the end of K-exhausting experiment the fixed ammonium content increased in most soils studied.However,it decreased in smom temperate soils.Generally,fixation of added NH4+ could not be found either before or after K-exhausting experiment for highly weathered soils,including tropical soils and soils derived from granite-gneiss or Quaternary red clays in the subtropic zone,while for most soils in the Yangtze River dalta the NH4+ fixation capacity was rather high and increased significantly in the K-exhausted soils.

  3. Production of Ammonium Lactate by Fed-batch Fermentation of Rhizopus oryzae from Corncob Hydrolysate

    Institute of Scientific and Technical Information of China (English)

    BAI Dong-mei; LI Shi-zhong; LIN Fang-qian

    2004-01-01

    L- (+)-Lactic acid production from corncob hydrolysate as a cheap carbohydrate source by fed-batch fermentation of Rhizopus oryzae HZS6 was studied. After 96 h of fermentation in a 5 L fermentor, the final concentration of ammonium L-(+)-lactate, average productivity(based on initial xylose concentration) and max(+)-lactate was 98.8%.

  4. Radiolysis of aqueous solutions of ammonium bicarbonate over a large dose range

    DEFF Research Database (Denmark)

    Draganic, Z.D.; Negrón-Mendoza, A.; Sehested, K.;

    1991-01-01

    Oxygen-free aqueous solutions of 0.05 mol dm-3 ammonium and sodium bicarbonate were studied after receiving various doses of Co-60 gammas (0.01-400 kGy) or 0.5-20 Gy pulses of 10 Mev electrons. Formate and oxalate were found to be the main radiolytic products, in addition to trace amounts...

  5. Aqueous Ammonia or Ammonium Hydroxide? Identifying a Base as Strong or Weak

    Science.gov (United States)

    Sanger, Michael J.; Danner, Matthew

    2010-01-01

    When grocery stores sell solutions of ammonia, they are labeled "ammonia"; however, when the same solution is purchased from chemical supply stores, they are labeled "ammonium hydroxide". The goal of this experiment is for students to determine which name is more appropriate. In this experiment, students use several different experimental methods…

  6. Mechanism studies on nitrogen removal when treating ammonium-rich leachate by sequencing batch biofilm reactor

    Institute of Scientific and Technical Information of China (English)

    XU Zhengyong; YANG Zhaohui; ZENG Guangming; XIAO Yong; DENG Jiuhua

    2007-01-01

    The nitrogen removal mechanism was studied and analyzed when treating the ammonium-rich landfill leachate by a set of sequencing batch biofilm reactors(SBBRs),which was designed independently.At the liquid temperature of(32±0.4)℃,and after a 58-days domestication period and a 33-days stabilization period.the efficiency of ammonium removal in the SBBR went up to 95%.Highly frequent intermittent aeration suppressed the activity of nitratebacteria.and also eliminated the influence on the activity of anaerobic ammonium oxidation(ANAMMOX)bacteria and nitritebacteria.This influence was caused by the accumulation of nitrous acid and the undulation of pH.During the aeration stage,the concentration of dissolved oxygen was controlled at 1.2-1.4 mg/L.The nitritebacteria became dominant and nitrite accumulated gradually.During the anoxic stage,along with the concentration debasement of the dissolved oxygen,ANAMMOX bacteria became dominant;then,the nitrite that was accumulated in the aeration stage was wiped off with ammonium simultaneously.

  7. Effects of high ammonium level on biomass accumulation of common duckweed Lemna minor L.

    Science.gov (United States)

    Wang, Wenguo; Yang, Chuang; Tang, Xiaoyu; Gu, Xinjiao; Zhu, Qili; Pan, Ke; Hu, Qichun; Ma, Danwei

    2014-12-01

    Growing common duckweed Lemna minor L. in diluted livestock wastewater is an alternative option for pollutants removal and consequently the accumulated duckweed biomass can be used for bioenergy production. However, the biomass accumulation can be inhibited by high level of ammonium (NH4 (+)) in non-diluted livestock wastewater and the mechanism of ammonium inhibition is not fully understood. In this study, the effect of high concentration of NH4 (+) on L. minor biomass accumulation was investigated using NH4 (+) as sole source of nitrogen (N). NH4 (+)-induced toxicity symptoms were observed when L. minor was exposed to high concentrations of ammonium nitrogen (NH4 (+)-N) after a 7-day cultivation. L. minor exposed to the NH4 (+)-N concentration of 840 mg l(-1) exhibited reduced relative growth rate, contents of carbon (C) and photosynthetic pigments, and C/N ratio. Ammonium irons were inhibitory to the synthesis of photosynthetic pigments and caused C/N imbalance in L. minor. These symptoms could further cause premature senescence of the fronds, and restrain their reproduction, growth and biomass accumulation. L. minor could grow at NH4 (+)-N concentrations of 7-84 mg l(-1) and the optimal NH4 (+)-N concentration was 28 mg l(-1). PMID:25056754

  8. Persistence of selected ammonium- and phosphonium-based ionic liquids in urban park soil microcosms

    DEFF Research Database (Denmark)

    Sydow, Mateusz; Szczepaniak, Zuzanna; Framski, Grzegorz;

    2015-01-01

    Knowledge about biodegradability of ionic liquids (ILs) in terrestrial systems is limited. Here, using urban park soil microcosms spiked with either ammonium- or phosphonium-based ILs [didecyldimethylammonium 3-amino-1,2,4-triazolate, benzalkonium 3-amino-1,2,4-triazolate, trihexyl...

  9. 75 FR 55991 - Ammonium Formate; Exemption from the Requirement of a Tolerance

    Science.gov (United States)

    2010-09-15

    ... April 21, 2006 (71 FR 20671) (FRL-8067- 3), EPA issued a notice pursuant to section 408 of FFDCA, 21 U.S..., and dispersing agents; propellants in aerosol dispensers; microencapsulating agents; and emulsifiers..., and terrestrial snails, metabolic ammonium is converted into uric acid, which is solid, and...

  10. Long alkyl chain bis-quaternary ammonium-based ionic liquids as biologically active xanthene dyes

    Energy Technology Data Exchange (ETDEWEB)

    Pernak, Juliusz; Swierczynska, Anna; Walkiewicz, Filip [Poznan Univ. of Technology, Poznan (Poland). Faculty of Chemical Technology; Krystkowiak, Ewa [A. Mickiewicz University, Poznan, (Poland). Faculty of Chemistry; Maciejewski, Andrzej [A. Mickiewicz University, Poznan (Poland). Centre of Ultrafast Laser Spectroscopy

    2009-07-01

    New examples of air- and moisture-stable, hydrophobic and hydrophilic bis-quaternary ammonium derived ionic liquids have been prepared. These ionic liquids have been proposed to act as biological active dyes with characteristic unique physicochemical properties, providing alternatives to some conventional anionic xanthene dyes such as eosine Y, fluorescein and erythrosine. (author)

  11. Recovery of ammonium perrhenate from molybdenite concentrate leaching solutions and its thermic dissociation

    International Nuclear Information System (INIS)

    The recovery of ammonium perrhenate from domestic molybdenite concentrate of direct electrochemical leaching molybdate-rhenate solutions and its dissociation process is investigated in order to obtain pure rhenium thirdoxide. By the method of thermogravimetric and differential-thermic analysis mechanism for perrhenate → bioxide passage is discovered

  12. Synthesis and Spectroscopic Characterisation of N-Alkyl Quaternary Ammonium Salts Typical Precursors of Cyanines

    Directory of Open Access Journals (Sweden)

    P. Almeida

    2002-03-01

    Full Text Available The synthesis and spectroscopic characterisation of some representative N-alkylsubstituted quaternary ammonium salts derived from benzothiazole, benzoxazole, benzoselenazole, indole and quinoline are described. These heterocyclic salts, bearing an activated methyl group in the 2-position in relation to the nitrogen atom and N-methyl, -pentyl, -hexyl and -decyl chains, are typical precursors of cyanine dyes.

  13. Interaction between Ammonium Toxicity and Green Tide Development Over Seagrass Meadows

    DEFF Research Database (Denmark)

    Marin, Francisco Moreno; Vergara, Juan J.; Pérez-Llorens, J. Lucas;

    2016-01-01

    Eutrophication affects seagrasses negatively by increasing light attenuation through stimulation of biomass of fast-growing, bloom-forming algae and because high concentrations of ammonium in the water can be toxic to higher plants. We hypothesized nevertheless, that moderate amounts of nitrophil...

  14. Different species of basil need different ammonium to nitrate ratio in hydroponics' system

    Directory of Open Access Journals (Sweden)

    M. SAADATIAN

    2015-12-01

    Full Text Available Basil is a very important medicinal plant and culinary spice, and is marketed fresh, dried or frozen. In crop nutrition, nitrogen is essential for plant growth and as a macro-element, is part of the proteins’ structure and participates in the metabolic processes involved in the synthesis and energy transfer. It has been shown that a balance between ammonium and nitrate favors plant growth and that the degree of benefit varies among crops. This study was conducted to evaluate the growth of two varieties of basil in function of four nutrient solutions containing different NH4+/NO3- ratios. Results showed that different variety response differently to nutrient solution. Although the highest yield in both varieties (sweet and purple was obtained when fed by nutrient solution without ammonium but their response on quality indices were different due to nitrate ammonium ratio in nutrient solutions. The highest total phenol content of sweet and purple basil was 92 and 100 mg gallic acid equivalent per gram of dry weight respectively, while the highest antioxidant capacity was obtained in purple variety grown in nutrient solution 2 (NH4+:1/NO3:4 and the lowest value were related to sweet variety with the same nutrient solution. Moderate content of total nitrogen can be suitable for sweet variety while for purple variety nutrient solution with low amount of ammonium can be more suitable.

  15. Computer model of hydroponics nutrient solution pH control using ammonium.

    Science.gov (United States)

    Pitts, M; Stutte, G

    1999-01-01

    A computer simulation of a hydroponics-based plant growth chamber using ammonium to control pH was constructed to determine the feasibility of such a system. In nitrate-based recirculating hydroponics systems, the pH will increase as plants release hydroxide ions into the nutrient solution to maintain plant charge balance. Ammonium is an attractive alternative to traditional pH controls in an ALSS, but requires careful monitoring and control to avoid overdosing the plants with ammonium. The primary advantage of using NH4+ for pH control is that it exploits the existing plant nutrient uptake charge balance mechanisms to maintain solution pH. The simulation models growth, nitrogen uptake, and pH of a l-m2 stand of wheat. Simulation results indicated that ammonium-based control of nutrient solution pH is feasible using a proportional integral controller. Use of a 1 mmol/L buffer (Ka = 1.6 x 10(-6)) in the nutrient solution is required.

  16. (Methyl)ammonium transport in the nitrogen-fixing bacterium Azospirillum brasilense.

    Science.gov (United States)

    Van Dommelen, A; Keijers, V; Vanderleyden, J; de Zamaroczy, M

    1998-05-01

    An ammonium transporter of Azospirillum brasilense was characterized. In contrast to most previously reported putative prokaryotic NH4+ transporter genes, A. brasilense amtB is not part of an operon with glnB or glnZ which, in A. brasilense, encode nitrogen regulatory proteins PII and PZ, respectively. Sequence analysis predicts the presence of 12 transmembrane domains in the deduced AmtB protein and classifies AmtB as an integral membrane protein. Nitrogen regulates the transcription of the amtB gene in A. brasilense by the Ntr system. amtB is the first gene identified in A. brasilense whose expression is regulated by NtrC. The observation that ammonium uptake is still possible in mutants lacking the AmtB protein suggests the presence of a second NH4+ transport mechanism. Growth of amtB mutants at low ammonium concentrations is reduced compared to that of the wild type. This suggests that AmtB has a role in scavenging ammonium at low concentrations.

  17. Towards a General Understanding of Carbonyl-Stabilised Ammonium Ylide-Mediated Epoxidation Reactions.

    Science.gov (United States)

    Novacek, Johanna; Roiser, Lukas; Zielke, Katharina; Robiette, Raphaël; Waser, Mario

    2016-08-01

    The key factors for carbonyl-stabilised ammonium ylide-mediated epoxidation reactions were systematically investigated by experimental and computational means and the hereby obtained energy profiles provide explanations for the observed experimental results. In addition, we were able to identify the first tertiary amine-based chiral auxiliary that allows for high enantioselectivities and high yields for such epoxidation reactions.

  18. Isotopic and elemental profiling of ammonium nitrate in forensic explosives investigations

    NARCIS (Netherlands)

    Brust, H.; Koeberg, M.; Heijden, A. van der; Wiarda, W.; Mügler, I.; Schrader, M.; Vivo-Truyols, G.; Schoenmakers, P.; Asten, A. van

    2015-01-01

    Ammonium nitrate (AN) is frequently encountered in explosives in forensic casework. It is widely available as fertilizer and easy to implement in explosive devices, for example by mixing it with a fuel. Forensic profiling methods to determine whether material found on a crime scene and material retr

  19. Biomass burning in eastern Europe during spring 2006 caused high deposition of ammonium in northern Fennoscandia

    DEFF Research Database (Denmark)

    Karlsson, Per Erik; Ferm, Martin; Pihl Karlsson, Gunilla;

    2013-01-01

    High air concentrations of ammonium were detected at low and high altitude sites in Sweden, Finland and Norway during the spring 2006, coinciding with polluted air from biomass burning in eastern Europe passing over central and northern Fennoscandia. Unusually high values for throughfall deposition...... Elsevier Ltd. All rights reserved....

  20. Ammonium metavanadate: A novel catalyst for synthesis of 2-substituted benzimidazole derivatives

    Institute of Scientific and Technical Information of China (English)

    Ganesh R. Jadhav; Mohammad U. Shaikh; Rajesh P. Kale; Charansingh H. Gill

    2009-01-01

    Ammonium metavanadate (10 tool%) was found to be a useful catalyst for the synthesis of various 2-substituted aryl benzimidazoles. It was used as an oxidizing agent for the condensation of o-pbenylenediamine with different substituted aryl aldehydes at room temperature in ethanol. The method was proved to be simple, convenient and the product was isolated with good yields (79-91%).