WorldWideScience

Sample records for acid media ehkstraktsionnye

  1. On hydrazine oxidation in nitric acid media

    International Nuclear Information System (INIS)

    Zil'berman, B.Ya.; Lelyuk, G.A.; Mashkin, A.N.; Yasnovitskaya, A.L.

    1988-01-01

    Yield of products of radiolytic ( 60 Co gamma radiation) and chemical hydrazine (HZ) oxidation in nitric acid media is studied. Under radiolyte HZ oxidation by nitric acid hydrazoic acid, ammonia and nitrogen appear to be the reaction products. HN 3 yield maximum under HZN oxidation makes up ∼ 0.35 mol per a mol of oxiduzed HZN. Under chemical oxidation HZN is oxidized by HNO 3 according to reaction catalysed by technetium HN 3 yield makes up ∼ 0.35 mol per a mol of oxidized HZN. Radiation-chemical oxidation of HN 3 proceeds up to its complete decomposition, decomposition rate is comparable with HZ oxidation rate. Under the chemical oxidation HN 3 is more stable, it is slowly decomposed after complete HZ decomposition

  2. Dissolution mechanism of aluminum hydroxides in acid media

    Science.gov (United States)

    Lainer, Yu. A.; Gorichev, I. G.; Tuzhilin, A. S.; Gololobova, E. G.

    2008-08-01

    The effects of the concentration, temperature, and potential at the hydroxide/electrolyte interface on the aluminum hydroxide dissolution in sulfuric, hydrochloric, and perchloric acids are studied. The limiting stage of the aluminum hydroxide dissolution in the acids is found to be the transition of the complexes that form on the aluminum hydroxide surface from the solid phase into the solution. The results of the calculation of the acid-base equilibrium constants at the oxide (hydroxide)/solution interface using the experimental data on the potentiometric titration of Al2O3 and AlOOH suspensions are analyzed. A mechanism is proposed for the dissolution of aluminum hydroxides in acid media.

  3. Specific acid catalysis and Lewis acid catalysis of Diels–Alder reactions in aqueous media

    NARCIS (Netherlands)

    Mubofu, Egid B.; Engberts, Jan B.F.N.

    2004-01-01

    A comparative study of specific acid catalysis and Lewis acid catalysis of Diels–Alder reactions between dienophiles (1, 4 and 6) and cyclopentadiene (2) in water and mixed aqueous media is reported. The reactions were performed in water with copper(II) nitrate as the Lewis acid catalyst whereas

  4. Specific acid catalysis and Lewis acid catalysis of Diels-Alder reactions in aqueous media

    NARCIS (Netherlands)

    Mubofu, E.B.; Engberts, J.B.F.N.

    A comparative study of specific acid catalysis and Lewis acid catalysis of Diells-Alder reactions between dienophiles (1, 4 and 6) and cyclopentadiene (2) in water and mixed aqueous media is reported. The reactions were performed in water with copper(II) nitrate as the Lewis acid catalyst whereas

  5. The coulometric titration of acids and bases in dimethylsulfoxide media

    NARCIS (Netherlands)

    Bos, M.; IJpma, S.T.; Dahmen, E.A.M.F.

    1976-01-01

    The coulometric titration of 20–200 μeq of acids and bases in DMSO media is described. In the titration of bases, the electro-oxidation of hydrogen at a platinized platinum electrode is used as the source of protons. The conditions for 100 % current efficiency at this electrode are low current

  6. Nitrous Acid as an Oxidant in Acidic Media

    Science.gov (United States)

    1979-09-25

    current work is the account of Ogsts and Sawski3 who studied the oxidation of benzyl ethers at 90C in acidic, aqueous dioxane. They found an increase in...and G. Tobin, Chem. Com., 180 (1978); (b) J. Hoggett , R. Moodie, and K. Schofield, Chem. Comm., 605 (1969). 15. (a) B. Challis and A. Lawson. J. Chem

  7. Colorimetric study of oxidation kinetics of thiolactic acid (2 - mercaptopropionic acid) by hexacyanoferrate (III) in acid and alkaline media

    International Nuclear Information System (INIS)

    Kachhwaha, O.P.; Potter, P.C.; Kapoor, R.C.

    1985-01-01

    The oxidation kinetics of thiolactic acid by hexacyanoferrate (III) in acid and alkaline media employing the calorimetric method have been described. The two compounds react in equimolar ratio in both media, but the kinetic results are different in both media. In acid medium the total order is three, two with respect to thiol and one in oxidant. The rate of the reaction shows an inverse proportionality to (H + ) and also varies inversely with decreasing dielectric constant of the medium. In alkaline medium, the total order of the reaction is two, being unity in each reactant. The rate increases with increased pH value. Additions of ferrocyanide and dithio dilactic acid have no effect on the rate in both media. Additions of a neutral electrolyte does not affect the rate in the acid medium, while a positive salt effect was observed in an alkaline medium. Activation parameters have been evaluated in both media and in a medium of low dialectric. Different reaction schemes have been proposed for acid and alkaline media and have satisfactory explained the experimental data, except for the pH rate. (author)

  8. Boric Acid Catalyzed Convenient Synthesis of Benzimidazoles in Aqueous Media

    OpenAIRE

    Poor Heravi, Mohammad Reza; Ashori, Marjan

    2013-01-01

    Synthesis of benzimidazoles has been developed by the o-phenylenediamine with aldehydes using boric acid an efficient catalyst under mild reaction conditions in aqueous media. The product is applicable to aryl and heteroaryl aldehydes. This reaction led to the formation of benzimidazoles new derivatives in good yields. The FT-IR, 19F-NMR, 1H-NMR, 13C-NMR spectra and elemental analysis confirm the structure of compounds.

  9. Boric Acid Catalyzed Convenient Synthesis of Benzimidazoles in Aqueous Media

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Poor Heravi

    2013-01-01

    Full Text Available Synthesis of benzimidazoles has been developed by the o-phenylenediamine with aldehydes using boric acid an efficient catalyst under mild reaction conditions in aqueous media. The product is applicable to aryl and heteroaryl aldehydes. This reaction led to the formation of benzimidazoles new derivatives in good yields. The FT-IR, 19F-NMR, 1H-NMR, 13C-NMR spectra and elemental analysis confirm the structure of compounds.

  10. Rhenium(V) complexing with benzimidazole in acidic media

    International Nuclear Information System (INIS)

    Zakaeva, R.Sh.; Gagieva, S.Ch.; Kaloev, N.I.; Bukov, N.N.; Panyushkin, V.T.

    2003-01-01

    Coordination compounds of rhenium(V) with 1H-benzimidazole (L) separated from acid media: (HL) 2 [ReOX 5 ](H 2 O) n and [ReOL x X y (H 2 O) z ](H 2 O) n (HL and L - protonated and deprotonated forms of benzimidazole; X = Cl - , Br - ) were studied by the methods of IR spectroscopy, 1 H NMR spectroscopy and thermal gravimetric analysis. Methods of ligand coordination in the complexes are discussed on the basis of data obtained [ru

  11. Formation of organic acids from trace carbon in acidic oxidizing media

    International Nuclear Information System (INIS)

    Terrassier, C.

    2003-01-01

    oxidation reactions by 3 N nitric acid identified in solution are also self-catalyzed by nitrous acid. Complete desorption of the carbon 14 in the dissolution off-gas assumes that ail the organic compounds in solution are mineralized. While the high molecular weight species are easily oxidized, acetic acid exhibits considerable stability in conventional dissolution media and its mineralization would require either very long residence times in nitrous fumes or the use of more powerful oxidizing agents in solution. (author) [fr

  12. Chitosan-caffeic acid-genipin films presenting enhanced antioxidant activity and stability in acidic media.

    Science.gov (United States)

    Nunes, Cláudia; Maricato, Élia; Cunha, Ângela; Nunes, Alexandra; da Silva, José A Lopes; Coimbra, Manuel A

    2013-01-02

    The use of chitosan films has been limited due to their high degradability in aqueous acidic media. In order to produce chitosan films with high antioxidant activity and insoluble in acid solutions caffeic acid was grafted to chitosan by a radical mechanism using ammonium cerium (IV) nitrate (60 mM). Genipin was used as cross-linker. This methodology originated films with 80% higher antioxidant activity than the pristine film. Also, these films only lost 11% of their mass upon seven days immersion into an aqueous solution at pH 3.5 under stirring. The films surface wettability (contact angle 105°), mechanical properties (68 MPa of tensile strength and 4% of elongation at break), and thermal stability for temperatures lower than 300 °C were not significantly influenced by the covalent linkage of caffeic acid and genipin to chitosan. Due to their characteristics, mainly higher antioxidant activity and lower solubility, these are promising materials to be used as active films. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Study of radium extraction mechanisms from scales by leaching in different acidic and alkaline media

    International Nuclear Information System (INIS)

    Al-Masri, M. S.; Gafar, M.; Al-Kurdi, H.

    2002-07-01

    The present report shows the results of leaching experiments for scales containing naturally occuring radioactive materials using different acidic and alkaline media. The obtained result can be used for defining the method of safe disposal of such waste. Leaching solutions used in this study were distilled water, mineral acids (sulpharic acid, hydrochloric acid and nitric acid), sodium, potassium hydroxides, ammonium oxalate EDTA, sodium carbonate, potassium acetate, and a mixture of potassium chloride and hydrochloric acid. The results have shown that the extraction ratio of radium-226, the most abundant isotope in scales, is very low and even negligible using all different media. This indicates that all scales produced in Syrian oil fields do not require any chemical preparation before disposal. In addition, the effect of both stirring time of phrases and concentration of leaching media that may affect the radium transfer process from solid phase to aqueous phase have been investigated were no measurable amount being observed in the leachate. (author)

  14. Thermometric titration of some monoprotic and diprotic acids in aqueous and non-aqueous media.

    Science.gov (United States)

    Harries, R J

    1968-12-01

    Some mono- and diprotic acids have been titrated thermometrically with strong alkalis in aqueous and non-aqueous media. Thermograms with sharp arrest points were obtained, from which heats of neutralization were measured. Heats of neutralization in the media used were compared and an effect attributable to hydrogen bonding was found.

  15. Speciation of technetium in acidic media: effect of α radiations

    International Nuclear Information System (INIS)

    Denden, Ibtihel

    2013-01-01

    This project is part of the fundamental study of technetium speciation in highly acidic medium. The behaviour of technetium in HTFMS was carried out in the absence then in the presence of a irradiation. Given these two different conditions, spectrophotometric results of Tc(VII) reduction are similar. XAS analysis indicates the formation of a cyclic dimer of Tc(IV) complexed to triflate ligands and formulated asTc 2 O 2 (CF 3 SO 3 ) 4 (H 2 O)4. This compound is linearized to Tc(IV)-O-Tc(IV) with the increase of HTFMS concentration. At high concentration of HTFMS +98% (11.15 M), the protonated species TcO 3 (OH)(H 2 O) 2 which is formed in the absence of external ionizing radiations, is reduced to the V oxidation state under a irradiation. Structural characterization by EXAFS spectroscopy and DFT calculations suggests the formation of monomer species of Tc(V)-triflate complexes where [OTc(F 3 CSO 3 ) 2 (H 2 O)2] + and [OTc(F 3 CSO 3 ) 2 (OH) 2 ] - compounds were proposed. In concentrated H 2 SO 4 (CH 2 SO 4 ≥ 12 M), a-radiolysis experiments of Tc(VII) were performed in order to compare the radiolytic behaviour of Tc(VII) in both comparable media HTFMS and H 2 SO 4 . XANES studies show that radiolytic reduction of Tc(VII) leads to the formation of Tc(V)-Tc(VII) mixture in H 2 SO 4 13 M and just Tc(V) in 18 M of H 2 SO 4 . The analysis of EXAFS spectra is consistent with the formation of [TcO(HSO 4 ) 3 (H 2 O) 2 ] and [TcO(HSO 4 )3(H 2 O)(OH)] - monomer complexes in H 2 SO 4 13 M and [Tc(HSO 4 ) 3 (SO 4 )(H 2 O)] and [Tc(HSO 4 ) 3 (SO 4 )(OH)] - species at 18 M of H 2 SO 4 . (author)

  16. Effect of different media on production of lactic acid from whey by ...

    African Journals Online (AJOL)

    Whey containing 50 g.l -1 lactose was fermented to lactic acid in batch process by Lactobacillus bulgaricus. The impact of 5 different media with change in volume percent of whey and nutrient was investigated at 32 ± 0.5°C. Substrate consumption and lactic acid production were determined at 0, 12, 24, 36, 48, 60 and 72 h.

  17. Rapid anion exchange separation of fermium with mineral acid-methyl alcohol mixed media

    International Nuclear Information System (INIS)

    Usuda, S.; Shinohara, N.; Ichikawa, S.; Suzuki, T.

    1987-01-01

    Anion exchange separation of 250 Fm (30 m) synthesized by the 12 C+ 242 Pu and 16 O+ 238 U reactions was investigated with mineral acid-methyl alcohol mixed media at elevated temperature. Fermium was chromatographically separated from the other transplutonium elements, the target materials and an Al catcher foil by anion exchange with mixtures of nitric acid and methyl alcohol. By use of the mixed media of hydrochloric acid and methyl alcohol, Fm together with Cf was separated from Al, Am, Cm, Pu, U and from major fission products. The separation systems are suitable for rapid separation and immediate alpha-counting source preparation of Fm. (author) 22 refs.; 4 figs

  18. Study of the interaction metallic cation - ligand in concentrated phosphorus acid media

    International Nuclear Information System (INIS)

    Sefiani, N.; Azzi, M.; Hlaibi, M.; Kossair, A.

    2005-01-01

    The phosphoric acid is more and more used with a high purity. The recovery of recycling element (uranium, vanadium, rare earth...) and the elimination of toxic element (cadmium, molybdenum, lead...) contained in the phosphoric acid are generally realized by extraction or precipitation. It is then very important to understand these impurities behavior in the phosphoric media in order to control their elimination. In this work, the authors considered the presence of some metallic cations (V, Al, fe, U) and fluorides ions as impurity in concentrated phosphoric acid media. (A.L.B.)

  19. Suitability of peracetic acid for sterilization of media for mycoplasma cultures.

    Science.gov (United States)

    Wutzler, P; Sprössig, M; Peterseim, H

    1975-01-01

    The utility of peracetic acid for sterilization of serum and yeast extract additions to mycoplasma medium was studied by culturing six Mycoplasma species. Culture media containing additions that had been sterilized with peracetic acid proved to be as good as filtered components. The use of 0.05 to 0.1% peracetic acid is recommended to sterilize the serum and yeast extract additions since savings in time and equipment can be accomplished. PMID:1100656

  20. Corrosion Inhibition of Aluminium by Capparis deciduas in Acidic Media

    Directory of Open Access Journals (Sweden)

    P. Arora

    2007-01-01

    Full Text Available The inhibition efficiency of ethanolic extract of different parts of Capparis deciduas (Ker in acidic medium has been evaluated by mass loss and thermometric methods. Values of inhibition efficiency obtained from the two methods are in good agreement and are dependent upon the concentration of inhibitor and acid.

  1. Corrosion Inhibition of Aluminium by Capparis deciduas in Acidic Media

    OpenAIRE

    P. Arora; S. Kumar; M. K. Sharma; S. P. Mathur

    2007-01-01

    The inhibition efficiency of ethanolic extract of different parts of Capparis deciduas (Ker) in acidic medium has been evaluated by mass loss and thermometric methods. Values of inhibition efficiency obtained from the two methods are in good agreement and are dependent upon the concentration of inhibitor and acid.

  2. Prediction of molecular alignment of nucleic acids in aligned media

    International Nuclear Information System (INIS)

    Wu Bin; Petersen, Michael; Girard, Frederic; Tessari, Marco; Wijmenga, Sybren S.

    2006-01-01

    We demonstrate - using the data base of all deposited DNA and RNA structures aligned in Pf1-medium and RDC refined - that for nucleic acids in a Pf1-medium the electrostatic alignment tensor can be predicted reliably and accurately via a simple and fast calculation based on the gyration tensor spanned out by the phosphodiester atoms. The rhombicity is well predicted over its full range from 0 to 0.66, while the alignment tensor orientation is predicted correctly for rhombicities up to ca. 0.4, for larger rhombicities it appears to deviate somewhat more than expected based on structural noise and measurement error. This simple analytical approach is based on the Debye-Huckel approximation for the electrostatic interaction potential, valid at distances sufficiently far away from a poly-ionic charged surface, a condition naturally enforced when the charge of alignment medium and solute are of equal sign, as for nucleic acids in a Pf1-phage medium. For the usual salt strengths and nucleic acid sizes, the Debye-Huckel screening length is smaller than the nucleic acid size, but large enough for the collective of Debye-Huckel spheres to encompass the whole molecule. The molecular alignment is then purely electrostatic, but it's functional form is under these conditions similar to that for steric alignment. The proposed analytical expression allows for very fast calculation of the alignment tensor and hence RDCs from the conformation of the nucleic acid molecule. This information provides opportunities for improved structure determination of nucleic acids, including better assessment of dynamics in (multi-domain) nucleic acids and the possibility to incorporate alignment tensor prediction from shape directly into the structure calculation process. The procedures are incorporated into MATLAB scripts, which are available on request

  3. Aqueous citric acid as green reaction media for the synthesis of octahydroxanthenes

    Directory of Open Access Journals (Sweden)

    Camilo A. Navarro D.

    2013-08-01

    Full Text Available A simple, convenient and environmentally friendly one-pot procedure for the synthesis of 1,8-dioxo-octahydroxanthenes by the reaction of dimedone and aromatic aldehydes in aqueous citric acid is described. In this green synthetic protocol promoted by the reaction media, the use of any other catalysts and hazardous organic solvents are avoided, making the work up procedure greener and easier. The isolation of the products, obtained in good yields, is readily performed by filtration and crystallization from ethanol when required and the aqueous acidic media can be easily recycled and reused several times without significant loss of catalytic activity.

  4. The platinum catalysed decomposition of hydrazine in acidic media

    International Nuclear Information System (INIS)

    Ananiev, A.V.; Tananaev, I.G.; Brossard, Ph.; Broudic, J.C.

    2000-01-01

    Kinetic study of the hydrazine decomposition in the solutions of HClO 4 , H 2 SO 4 and HNO 3 in the presence of Pt/SiO 2 catalyst has been undertaken. It was shown that the kinetics of the hydrazine catalytic decomposition in HClO 4 and H 2 SO 4 are identical. The process is determined by the heterogeneous catalytic auto-decomposition of N 2 H 4 on the catalyst's surface. The platinum catalysed hydrazine decomposition in the nitric acid solutions is a complex process, including heterogeneous catalytic auto-decomposition of N 2 H 4 , reaction of hydrazine with catalytically generated nitrous acid and the catalytic oxidation of hydrazine by nitric acid. The kinetic parameters of these reactions have been determined. The contribution of each reaction in the total process is determined by the liquid phase composition and by the temperature. (authors)

  5. The removal of uranium from acidic media using ion exchange and/or extraction chromatography

    International Nuclear Information System (INIS)

    FitzPatrick, J.R.; Schake, B.S.; Murphy, J.; Holmes, K.; West, M.H.

    1996-06-01

    The separation and purification of uranium from either nitric acid or hydrochloric acid media can be accomplished by using either solvent extraction or ion-exchange. Over the past two years at Los Alamos, emerging programs are focused on recapturing the expertise required to do limited, small-quantity processing of enriched uranium. During this period of time, we have been investigating ion-addition, waste stream polishing is associated with this effort in order to achieve more complete removal of uranium prior to recycle of the acid. Extraction chromatography has been demonstrated to further polish the uranium from both nitric and hydrochloric acid media thus allowing for a more complete recovery of the actinide material and creation of less waste during the processing steps

  6. Diazotisation of Weakly Basic Aromatic and Heterocyclic Amines in Strongly Acid Media

    Science.gov (United States)

    Godovikova, Tamara I.; Rakitin, Oleg A.; Khmel'nitskii, Lenor I.

    1983-05-01

    The review is devoted to the diazotisation of weakly basic aromatic amines. The methods of synthesis of diazonium salts based on these amines by non-traditional methods are examined. Data on the mechanism of the diazotisation reaction in strongly acid media are surveyed. Reactions of diazonium salts leading to the synthesis of new compounds are presented. The bibliography includes 75 references.

  7. Hydroxylamine electrochemistry at low-index single-crystal platinum electrodes in acidic media

    NARCIS (Netherlands)

    Rosca, V.; Beltramo, G.L.; Koper, M.T.M.

    2004-01-01

    The electrochemistry of hydroxylamine at low-index single-crystal platinum electrodes in acidic media has been studied by voltammetry and in-situ FTIRRAS. Hydroxylamine (HAM) reactivity at platinum is largely controlled by interaction of the other components of the solution or products of the HAM

  8. Inhibition of corrosion of mild steel in acid media by N ...

    Indian Academy of Sciences (India)

    Wintec

    It acts as an anodic inhibitor. Thermodynamic and ... Thermo Electron Corporation Flash EA 1112 se- ries CHN analyser was used .... tiss et al 2001). In each acid media, maximum %IE was achieved at 11⋅494 × 10–4 M and a further increase in concentration did not cause any appreciable change in the performance of the ...

  9. Phosphoric acids as amplifiers of molecular chirality in liquid crystalline media

    NARCIS (Netherlands)

    Eelkema, R; Feringa, BL

    2006-01-01

    A new system for the double amplification of the molecular chirality of simple chiral amines in achiral liquid crystalline media is described. It involves a conformationally flexible phosphoric acid based receptor that by binding to chiral amines induces chirality in the liquid crystalline matrix.

  10. Redox chemistry of americium in nitric acid media

    Energy Technology Data Exchange (ETDEWEB)

    Picart, S.; Jobelin, I.; Armengol, G.; Adnet, JM

    2004-07-01

    The redox properties of the actinides are very important parameters for speciation studies and spent nuclear fuel reprocessing based on liquid-liquid extraction of actinides at different oxidation states (as in the Purex or Sesame process). They are also very useful for developing analytical tools including coulometry and redox titration. This study addressed the americium(IV)/americium(III) and americium(VI)/americium(V) redox couples, focusing on exhaustive acquisition of the thermodynamic and kinetic parameters of americium oxidation at an electrode in a complexing nitric acid medium. (authors)

  11. Redox chemistry of americium in nitric acid media

    International Nuclear Information System (INIS)

    Picart, S.; Jobelin, I.; Armengol, G.; Adnet, JM.

    2004-01-01

    The redox properties of the actinides are very important parameters for speciation studies and spent nuclear fuel reprocessing based on liquid-liquid extraction of actinides at different oxidation states (as in the Purex or Sesame process). They are also very useful for developing analytical tools including coulometry and redox titration. This study addressed the americium(IV)/americium(III) and americium(VI)/americium(V) redox couples, focusing on exhaustive acquisition of the thermodynamic and kinetic parameters of americium oxidation at an electrode in a complexing nitric acid medium. (authors)

  12. Removal of phosphorus from agricultural wastewaters using adsorption media prepared from acid mine drainage sludge

    Science.gov (United States)

    Sibrell, Philip L.; Montgomery, Gary A.; Ritenour, Kelsey L.; Tucker, Travis W.

    2009-01-01

    Excess phosphorus in wastewaters promotes eutrophication in receiving waterways. A??cost-effective method for the removal of phosphorus from water would significantly reduce the impact of such wastewaters on the environment. Acid mine drainage sludge is a waste product produced by the neutralization of acid mine drainage, and consists mainly of the same metal hydroxides used in traditional wastewater treatment for the removal of phosphorus. In this paper, we describe a method for the drying and pelletization of acid mine drainage sludge that results in a particulate media, which we have termed Ferroxysorb, for the removal of phosphorus from wastewater in an efficient packed bed contactor. Adsorption capacities are high, and kinetics rapid, such that a contact time of less than 5 min is sufficient for removal of 60-90% of the phosphorus, depending on the feed concentration and time in service. In addition, the adsorption capacity of the Ferroxysorb media was increased dramatically by using two columns in an alternating sequence so that each sludge bed receives alternating rest and adsorption cycles. A stripping procedure based on treatment with dilute sodium hydroxide was also developed that allows for recovery of the P from the media, with the possibility of generating a marketable fertilizer product. These results indicate that acid mine drainage sludges - hitherto thought of as undesirable wastes - can be used to remove phosphorus from wastewater, thus offsetting a portion of acid mine drainage treatment costs while at the same time improving water quality in sensitive watersheds.

  13. Carbon catalysts for electrochemical hydrogen peroxide production in acidic media

    DEFF Research Database (Denmark)

    Čolić, Viktor; Yang, Sungeun; Révay, Zsolt

    2018-01-01

    Hydrogen peroxide is a commodity chemical, as it is an environmentally friendly oxidant. The electrochemical production of H2O2 from oxygen and water by the reduction of oxygen is of great interest, as it would allow the decentralized, on-site, production of pure H2O2. The ability to run...... the reaction in an acidic electrolyte with high performance is particularly important, as it would allow the use of polymer solid electrolytes and the production of pH-neutral hydrogen peroxide. Carbon catalysts, which are cheap, abundant, durable and can be highly selective show promise as potential catalysts...... for such systems. In this work, we examine the electrocatalytic performance and properties of seven commercially available carbon materials for H2O2 production by oxygen electroreduction. We show that the faradaic efficiencies for the reaction lie in a wide range of 18-82% for different carbon catalysts. In order...

  14. Redox thermodynamic data of plutonium in acidic and carbonate media. Pu(V) stability

    International Nuclear Information System (INIS)

    Capdevila, H.

    1992-01-01

    Pu redox equilibria are studied in acidic and carbonate media in this thesis, to build a thermodynamic data bank consistent with the TDB (NEA-OECD) one and in connection with radioactive waste disposal programs. Literature is discussed and reinterpreted. The experimental method is tested with Uranium preliminary measurements. The reversible redox potentials (PuO 2 + and Pu 4+ /Pu 3+ ) are measured using the cyclic voltametric technique in perchloric media at several ionic strengths (from 0.5 to 3M) and temperatures (from 0 to 70 deg C). The Specific Interaction Theory (SIT) is used to measured activity coefficients and to extrapolate data to the standard conditions. The potentials variations versus temperature are linear in first approximation: the entropy changes are found constant from 0 to 70 deg C and the heat capacity changes are within uncertainties. The standard constant of PuO 2 + disproportionation into PuO 2 2+ and Pu 3+ is deduced from spectrophotometric measurements performed in perchloric media around pH=1 where Pu 4+ hydrolysis is discussed. The Pu non-reversible standard potentials (PuO 2 2+ /Pu 4+ for instance) are then calculated and validated with a spectrophotometric study of Pu 4+ formation from PuO 2 2+ and Pu 3+ in a 1M perchloric acidic solution. The Pu(VI/V) redox potential, activity coefficients and entropies are measured using the same technique in concentrated carbonate media. The limiting complex standard formation constants and the redox potential shifts (between acidic and carbonate media) are then discussed among the U, Np, Pu and Am actinides. A spectrophotometric study of the equilibrium between the complexes with 5 and 4 carbonate ligands allowed to measure Pu(IV) limiting complex stability at several ionic strengths. (author). 26 tabs., 46 figs., 95 refs

  15. In Situ Swelling Behavior of Chitosan-Polygalacturonic Acid/Hydroxyapatite Nanocomposites in Cell Culture Media

    Directory of Open Access Journals (Sweden)

    Rohit Khanna

    2010-01-01

    Full Text Available The molecular and mechanical characteristics of in situ degradation behavior of chitosan-polygalacturonic acid/hydroxyapatite (Chi-PgA-HAP nanocomposite films is investigated using Fourier Transform Infrared spectroscopy (FTIR, Atomic Force Microscopy (AFM, and modulus mapping techniques for up to 48 days of soaking in cell culture media. The surface molecular structure of media-soaked samples changes over the course of 48 days of soaking, as indicated by significant changes in phosphate vibrations (1200–900 cm−1 indicating apatite formation. Chitosan-Polygalacturonic acid polyelectrolyte complexes (PECs govern structural integrity of Chi-PgA-HAP nanocomposites and FTIR spectra indicate that PECs remain intact until 48 days of soaking. In situ AFM experiments on media-soaked samples indicate that soaking results in a change in topography and swelling proceeds differently at the initial soaking periods of about 8 days than for longer soaking. In situ modulus mapping experiments are done on soaked samples by probing ∼1–3 nm of surface indicating elastic moduli of ∼4 GPa resulting from proteins adsorbed on Chi-PgA-HAP nanocomposites. The elastic modulus decreases by ∼2 GPa over a long exposure to cell culture media (48 days. Thus, as water enters the Chi-PgA-HAP sample, surface molecular interactions in Chi-PgA-HAP structure occur that result in swelling, causing small changes in nanoscale mechanical properties.

  16. Study of Plant Cordia Dichotoma as Green Corrosion Inhibitor for Mild Steel in Different Acid Media

    OpenAIRE

    R. Khandelwal; S. K. Arora; S. P. Mathur

    2011-01-01

    The corrosion inhibition of mild steel using extracts of Cordia dichotoma in different acid media was investigated by mass loss and thermometric methods. The experiments were carried out at 299±0.2 K in presence of different concentrations of dry fruit, leaves and stem extracts of Cordia dichotoma. The results reveal that the alcoholic extracts of Cordia dichotoma is a better corrosion inhibitor than that of toxic chemicals. The fruit extract is more potent than leaves and stem extracts to in...

  17. Humic acid transport in saturated porous media: influence of flow velocity and influent concentration.

    Science.gov (United States)

    Wei, Xiaorong; Shao, Mingan; Du, Lina; Horton, Robert

    2014-12-01

    Understanding the transport of humic acids (HAs) in porous media can provide important and practical evidence needed for accurate prediction of organic/inorganic contaminant transport in different environmental media and interfaces. A series of column transport experiments was conducted to evaluate the transport of HA in different porous media at different flow velocities and influent HA concentrations. Low flow velocity and influent concentration were found to favor the adsorption and deposition of HA onto sand grains packed into columns and to give higher equilibrium distribution coefficients and deposition rate coefficients, which resulted in an increased fraction of HA being retained in columns. Consequently, retardation factors were increased and the transport of HA through the columns was delayed. These results suggest that the transport of HA in porous media is primarily controlled by the attachment of HA to the solid matrix. Accordingly, this attachment should be considered in studies of HA behavior in porous media. Copyright © 2014. Published by Elsevier B.V.

  18. Polyoxometalate electrocatalysts based on earth-abundant metals for efficient water oxidation in acidic media

    Science.gov (United States)

    Blasco-Ahicart, Marta; Soriano-López, Joaquín; Carbó, Jorge J.; Poblet, Josep M.; Galan-Mascaros, J. R.

    2018-01-01

    Water splitting is a promising approach to the efficient and cost-effective production of renewable fuels, but water oxidation remains a bottleneck in its technological development because it largely relies on noble-metal catalysts. Although inexpensive transition-metal oxides are competitive water oxidation catalysts in alkaline media, they cannot compete with noble metals in acidic media, in which hydrogen production is easier and faster. Here, we report a water oxidation catalyst based on earth-abundant metals that performs well in acidic conditions. Specifically, we report the enhanced catalytic activity of insoluble salts of polyoxometalates with caesium or barium counter-cations for oxygen evolution. In particular, the barium salt of a cobalt-phosphotungstate polyanion outperforms the state-of-the-art IrO2 catalyst even at pH < 1, with an overpotential of 189 mV at 1 mA cm-2. In addition, we find that a carbon-paste conducting support with a hydrocarbon binder can improve the stability of metal-oxide catalysts in acidic media by providing a hydrophobic environment.

  19. Optimization of culture media for enhancing gamma-linolenic acid production by Mucor hiemalis

    Directory of Open Access Journals (Sweden)

    Mina Mohammadi Nasr

    2016-03-01

    Full Text Available Introduction: g-linolenic acid is an essential fatty acid in human nutrition. In the present study, production of g-linolenic acid by Mucor hiemalis PTCC 5292 was evaluated in submerged fermentation. Materials and methods: The fermentation variables were chosen according to the fractional factorial design and further optimized via full factorial method. Four significant variables, glucose, peptone, ammonium nitrate and pH were selected for the optimization studies. The design consisted of total 16 runs consisting of runs at two levels for each factor with three replications of the center points. Results: The analysis of variance and three-dimensional response surface plot of effects indicated that variables were regarded to be significant for production of g-linolenic acid by Mucor hiemalis. Results indicated that fermentation at the optimum conditions (100 g/l glucose concentration; 1 g/l peptone; 1 g/l ammonium nitrate, and pH of 4.5 enhanced the g-linolenic acid production up to 709 mg/l. Discussion and conclusion: The results of this study indicated that higher g-linolenic acid yield can be achieved in a simple medium at high glucose and ammonium nitrate, low peptone concentrations and acidic pH by Mucor hiemalis PTCC 5292. This simple and low cost optimization condition of culture media can be applied for g-linolenic acid production at higher scale for pharmaceutical and nutritional industries. 

  20. Reversibility of Pt-Skin and Pt-Skeleton Nanostructures in Acidic Media.

    Science.gov (United States)

    Durst, Julien; Lopez-Haro, Miguel; Dubau, Laetitia; Chatenet, Marian; Soldo-Olivier, Yvonne; Guétaz, Laure; Bayle-Guillemaud, Pascale; Maillard, Frédéric

    2014-02-06

    Following a well-defined series of acid and heat treatments on a benchmark Pt3Co/C sample, three different nanostructures of interest for the electrocatalysis of the oxygen reduction reaction were tailored. These nanostructures could be sorted into the "Pt-skin" structure, made of one pure Pt overlayer, and the "Pt-skeleton" structure, made of 2-3 Pt overlayers surrounding the Pt-Co alloy core. Using a unique combination of high-resolution aberration-corrected STEM-EELS, XRD, EXAFS, and XANES measurements, we provide atomically resolved pictures of these different nanostructures, including measurement of the Pt-shell thickness forming in acidic media and the resulting changes of the bulk and core chemical composition. It is shown that the Pt-skin is reverted toward the Pt-skeleton upon contact with acid electrolyte. This change in structure causes strong variations of the chemical composition.

  1. Uranium (VI) transport in saturated heterogeneous media: Influence of kaolinite and humic acid.

    Science.gov (United States)

    Chen, Chong; Zhao, Kang; Shang, Jianying; Liu, Chongxuan; Wang, Jin; Yan, Zhifeng; Liu, Kesi; Wu, Wenliang

    2018-05-07

    Natural aquifers typically exhibit a variety of structural heterogeneities. However, the effect of mineral colloids and natural organic matter on the transport behavior of uranium (U) in saturated heterogeneous media are not totally understood. In this study, heterogeneous column experiments were conducted, and the constructed columns contained a fast-flow domain (FFD) and a slow-flow domain (SFD). The effect of kaolinite, humic acid (HA), and kaolinite/HA mixture on U(VI) retention and release in saturated heterogeneous media was examined. Media heterogeneity significantly influenced U fate and transport behavior in saturated subsurface environment. The presence of kaolinite, HA, and kaolinite/HA enhanced the mobility of U in heterogeneous media, and the mobility of U was the highest in the presence of kaolinite/HA and the lowest in the presence of kaolinite. In the presence of kaolinite, there was no difference in the amount of U released from the FFD and SFD. However, in the presence of HA and kaolinite/HA, a higher amount of U was released from the FFD. The findings in this study showed that medium structure and mineral colloids, as well as natural organic matter in the aqueous phase had significant effects on U transport and fate in subsurface environment. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Inhibitors for the corrosion of reactive metals: titanium and zirconium and their alloys in acid media

    International Nuclear Information System (INIS)

    Petit, J.A.; Chatainier, G.; Dabosi, F.

    1981-01-01

    The search for effective corrosion inhibitors for titanium and zirconium in acid media is growing because of the considerable increase in the use of these materials in chemical process equipment. It still remains limited, as appears from this review, because of the exceptionally high corrosion resistance of the metals. Titanium has received the greater attention. Its corrosion rate can be lowered by introduction in the medium of multivalent ions, inorganic and organic oxidants. Care should be taken to hold the concentration at a level exceeding some critical value, otherwise the corrosion rate increases. Complexing organic agents do not show such hazardous behaviour. The very rapid corrosion of titanium and zirconium in fluoride media may be lessened by complexing the fluoride ions. Though rarely encountered, localized corrosion may be avoided by using inhibitors. In some cases good corrosion inhibitors for titanium are dissolution accelerators for zirconium. (author)

  3. Fabrication of MCM-41 fibers with well-ordered hexagonal mesostructure controlled in acidic and alkaline media

    International Nuclear Information System (INIS)

    Jafarzadeh, A.; Sohrabnezhad, Sh.; Zanjanchi, M.A.; Arvand, M.

    2016-01-01

    In this paper, synthesis and characterization of two type morphologies of the MCM-41mesoporous material, nano and microfibers, were investigated by electrospinning technique. The synthesis was performed in acidic and alkaline media, separately. The MCM-41 morphologies were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray powder diffraction (XRD), and nitrogen adsorption–desorption measurement. Tetraethylorthosilicate (TEOS) and cetyltrimethylammonium bromide (CTAB) were used as silica and template sources for the synthesis of MCM-41 morphologies, respectively. The SEM results showed that MCM-41 nanofibers were spun in acidic media and microfibers of MCM-41 were produced in alkaline media. The XRD study revealed a long range structural ordering of mesoporous materials. The TEM results indicated rough surfaces with uniform average diameter 200 nm for nanofibers and 2 µm for microfibers. The pore diameter and surface area of calcined MCM-41 nanofibers were 2.2 nm and 970 m 2 /g, respectively. For the MCM-41 microfibers, pore sizes of 2.7 nm and surface areas 420 m 2 /g was measured. - Graphical abstract: Electrospinning method was used for fabricating of MCM-41 microfibers from TEOS in alkaline media (top) and MCM-41 nanofibers in acidic media (bottom). - Highlights: • Synthesis of MCM-41 nanofibers and microfibers by electrospinning technique. • MCM-41 nanofibers were synthesized in acidic media. • MCM-41 manofibers spun in alkaline media. • Electrospinning was a simple method for preparing of fibers with respect to chemical method.

  4. Study of the interaction metallic cation - ligand in concentrated phosphorus acid media; Etude de l'interaction cation metallique - ligand en milieu acide phosphorique concentre

    Energy Technology Data Exchange (ETDEWEB)

    Sefiani, N.; Azzi, M.; Hlaibi, M. [Faculte des Sciences Ain Chock, Laboratoire d' Electrochimie et Chimie de l' Environnement (LECE), Casablanca (Morocco); Kossair, A. [Centre de Recherche des Phosphates Mineraux (CERPHOS), Casablanca (Morocco)

    2005-07-01

    The phosphoric acid is more and more used with a high purity. The recovery of recycling element (uranium, vanadium, rare earth...) and the elimination of toxic element (cadmium, molybdenum, lead...) contained in the phosphoric acid are generally realized by extraction or precipitation. It is then very important to understand these impurities behavior in the phosphoric media in order to control their elimination. In this work, the authors considered the presence of some metallic cations (V, Al, fe, U) and fluorides ions as impurity in concentrated phosphoric acid media. (A.L.B.)

  5. Investigations of corrosion films formed on API-X52 pipeline steel in acid sour media

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Espejel, A. [Instituto Politecnico Nacional, Departamento de Ingenieria Metalurgica, IPN-ESIQIE, UPALM Ed. 7, Zacatenco 07738, Mexico, D.F. (Mexico); Dominguez-Crespo, M.A. [Instituto Politecnico Nacional, CICATA-Unidad Altamira-Tamaulipas, km 14.5, Carretera Tampico-Puerto Industrial Altamira, 89600 Altamira, Tamps (Mexico); Cabrera-Sierra, R. [Instituto Politecnico Nacional, Departamento de Ingenieria Quimica Industrial, IPN-ESIQIE, UPALM Ed. 7, Zacatenco 07738, Mexico, D.F. (Mexico); Rodriguez-Meneses, C. [Instituto Politecnico Nacional, Departamento de Ingenieria Metalurgica, IPN-ESIQIE, UPALM Ed. 7, Zacatenco 07738, Mexico, D.F. (Mexico); Arce-Estrada, E.M., E-mail: earce@ipn.m [Instituto Politecnico Nacional, Departamento de Ingenieria Metalurgica, IPN-ESIQIE, UPALM Ed. 7, Zacatenco 07738, Mexico, D.F. (Mexico)

    2010-07-15

    Corrosion films formed by voltammetry using different switching potentials and by immersion on API-X52 pipeline steel in simulated acid sour media (NACE ID182) have been characterized using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Linear Polarization and Electrochemical Impedance Spectroscopy (EIS) techniques. XRD and EDS analysis showed that the films are mainly composed of sulphide compounds (mackinawite, troilite, marcasite and pyrite) as well as iron oxides, as steel damage increases. Across SEM micrographs the corrosion films formed by potentiodynamic and immersion tests are very similar, covering most of the steel. Polarization and EIS results corroborate poor behavior against corrosion.

  6. Kinetics of oxygen reduction reaction at electrochemically fabricated tin-palladium bimetallic electrocatalyst in acidic media

    Energy Technology Data Exchange (ETDEWEB)

    Miah, Md. Rezwan, E-mail: mrmche@yahoo.co [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Mail Box G1-5, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan); Masud, Jahangir [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Mail Box G1-5, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan); Ohsaka, Takeo, E-mail: ohsaka@echem.titech.ac.j [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Mail Box G1-5, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan)

    2010-12-15

    In the present article, oxygen reduction reaction (ORR) at electrochemically fabricated tin-palladium (Sn-Pd) bimetallic electrocatalyst-modified glassy carbon (GC) electrode (Sn-Pd/GC electrode) in acidic media is addressed. Hydrodynamic voltammetric measurements were employed with a view to evaluating various kinetic parameters of the ORR at the Sn-Pd/GC electrode. The obtained results obviously demonstrated that the Sn-Pd bimetallic electrocatalyt substantially promoted the activity of the GC electrode and drove the ORR through an exclusive one-step four-electron pathway forming H{sub 2}O as the final product.

  7. Kinetics of oxygen reduction reaction at electrochemically fabricated tin-palladium bimetallic electrocatalyst in acidic media

    International Nuclear Information System (INIS)

    Miah, Md. Rezwan; Masud, Jahangir; Ohsaka, Takeo

    2010-01-01

    In the present article, oxygen reduction reaction (ORR) at electrochemically fabricated tin-palladium (Sn-Pd) bimetallic electrocatalyst-modified glassy carbon (GC) electrode (Sn-Pd/GC electrode) in acidic media is addressed. Hydrodynamic voltammetric measurements were employed with a view to evaluating various kinetic parameters of the ORR at the Sn-Pd/GC electrode. The obtained results obviously demonstrated that the Sn-Pd bimetallic electrocatalyt substantially promoted the activity of the GC electrode and drove the ORR through an exclusive one-step four-electron pathway forming H 2 O as the final product.

  8. Furfural production in biphasic media using an acidic ionic liquid as a catalyst.

    Science.gov (United States)

    Peleteiro, Susana; Santos, Valentín; Parajó, Juan C

    2016-11-20

    Ionic liquids are valuable tools for biorefineries. This study provides an experimental assessment on the utilization of an acidic ionic liquid (1-butyl-3-methylimidazolium hydrogen sulfate) as a catalyst for furfural production in water/solvent media. The substrates employed in experiments were commercial xylose (employed as a reference compound) or hemicellulosic saccharides obtained by hydrothermal processing of Eucalyptus globulus wood (which were employed as produced, after membrane concentration or after freeze-drying). A variety of reaction conditions (defined by temperature, reaction time and type of organic solvent) were considered. The possibility of recycling the catalyst was assessed in selected experiments. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Investigations of corrosion films formed on API-X52 pipeline steel in acid sour media

    International Nuclear Information System (INIS)

    Hernandez-Espejel, A.; Dominguez-Crespo, M.A.; Cabrera-Sierra, R.; Rodriguez-Meneses, C.; Arce-Estrada, E.M.

    2010-01-01

    Corrosion films formed by voltammetry using different switching potentials and by immersion on API-X52 pipeline steel in simulated acid sour media (NACE ID182) have been characterized using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Linear Polarization and Electrochemical Impedance Spectroscopy (EIS) techniques. XRD and EDS analysis showed that the films are mainly composed of sulphide compounds (mackinawite, troilite, marcasite and pyrite) as well as iron oxides, as steel damage increases. Across SEM micrographs the corrosion films formed by potentiodynamic and immersion tests are very similar, covering most of the steel. Polarization and EIS results corroborate poor behavior against corrosion.

  10. Study of Plant Cordia Dichotoma as Green Corrosion Inhibitor for Mild Steel in Different Acid Media

    Directory of Open Access Journals (Sweden)

    R. Khandelwal

    2011-01-01

    Full Text Available The corrosion inhibition of mild steel using extracts of Cordia dichotoma in different acid media was investigated by mass loss and thermometric methods. The experiments were carried out at 299±0.2 K in presence of different concentrations of dry fruit, leaves and stem extracts of Cordia dichotoma. The results reveal that the alcoholic extracts of Cordia dichotoma is a better corrosion inhibitor than that of toxic chemicals. The fruit extract is more potent than leaves and stem extracts to inhibit the corrosion rate. The study seeks to investigate the possibility of using extracts of Cordia dichotoma as a green corrosion inhibitor for mild steel.

  11. Separation of DR synthesized Ti-Mg Alloy by dissolution of waste by-products in acid media

    CSIR Research Space (South Africa)

    Mushove, T

    2010-06-01

    Full Text Available The objective of this work is to isolate synthesized Ti-Mg alloy powder through leaching out of MgO and any unreduced oxides of Titanium. Leaching media investigated are H2SO4, HCl and organic acids ascorbic acid/oxalic and L-cysteine /ascorbic...

  12. Spectrographic study of neodymium complexing with hydroxyethylidenediphosphonic acid in acid media

    International Nuclear Information System (INIS)

    Afonin, E.G.; Pechurova, N.I.; Martynenko, L.I.

    1987-01-01

    High resolution spectrography is used to study neodymium (3) complexing with hydroxyethylidenediphosphonic acid (H 4 X) in aqueous solution with hydrogen ion concentration being 0.35-4.5 g-ion/l. It is shown that complex of NdH 2 X + composition characterized by λ=4290 A absorption band in electron spectrum in transition range 4 I 9/2 → 2 P 1/2 is formed in a system. The lgK stab =5.62 ± 0.07 value is calculated. It is supposed that high stability of a complex is conditioned by participation of ligand nondissociated alcohol group in coordination

  13. Ozonation of azo dyes (Orange II and Acid Red 27) in saline media

    International Nuclear Information System (INIS)

    Silva, Alessandra C.; Pic, Jean Stephane; Sant'Anna, Geraldo L.; Dezotti, Marcia

    2009-01-01

    Ozonation of two azo dyes was investigated in a monitored bench scale bubble column reactor (8.5-L), varying liquid media salt content (0, 1, 40 and 100 g L -1 , NaCl). In experiments with Orange II pH was varied (5, 7.5 and 9) but ozonation of Acid Red 27 was performed at pH 7.5. Ozone self-decomposition rate-constant increased with salt concentration. Color removal was very effective and fast achieved under all experimental conditions. For the two azo dyes tested, more than 98% of color intensity was removed in 30-min ozonation assays. However, only partial mineralization of azo dyes (45%-Orange II; 20%-Acid Red 27) was attained in such experiments. The degree of mineralization (TOC removal) was negatively affected by salt concentration. Biodegradation assays conducted by respirometry revealed the inhibitory effect of dye degradation products formed during ozonation.

  14. Media Screening for Obtaining Haematococcus pluvialis Red Motile Macrozooids Rich in Astaxanthin and Fatty Acids.

    Science.gov (United States)

    Butler, Thomas O; McDougall, Gordon J; Campbell, Raymond; Stanley, Michele S; Day, John G

    2017-12-26

    Astaxanthin from Haematococcus pluvialis is commercially produced in a two-stage process, involving green vegetative (macrozooid) and red aplanospore stages. This approach has been scaled up to an industrial process but constraints limit its commercial success and profitability, including: contamination issues, high pigment extraction costs, requirements for high light levels and photo-bleaching in the red stage. However, in addition to the aplanospore stage, this alga can produce astaxanthin in vegetative palmelloid and motile macrozooid cells. In this study, a two-stage process utilising different media in the green stage, with subsequent re-suspension in medium without nitrate was employed to optimise the formation of red motile macrozooids. Optimal growth in the green phase was obtained on cultivation under mixotrophic conditions in EG:JM media followed by re-suspension in medium without nitrate resulting in red motile macrozooids with an astaxanthin content of 2.74% (78.4% of total carotenoids) and a lipid content of 35.3% (rich in unsaturated fatty acids. It is envisaged that the red motile macrozooids could be harvested and fed as a whole-cell product directly in the animal feed and aquaculture sectors, or used as a blend of carotenoids and polyunsaturated fatty acids (PUFAs) in nutraceutical products.

  15. Media Screening for Obtaining Haematococcus pluvialis Red Motile Macrozooids Rich in Astaxanthin and Fatty Acids

    Directory of Open Access Journals (Sweden)

    Thomas O. Butler

    2017-12-01

    Full Text Available Astaxanthin from Haematococcus pluvialis is commercially produced in a two-stage process, involving green vegetative (macrozooid and red aplanospore stages. This approach has been scaled up to an industrial process but constraints limit its commercial success and profitability, including: contamination issues, high pigment extraction costs, requirements for high light levels and photo-bleaching in the red stage. However, in addition to the aplanospore stage, this alga can produce astaxanthin in vegetative palmelloid and motile macrozooid cells. In this study, a two-stage process utilising different media in the green stage, with subsequent re-suspension in medium without nitrate was employed to optimise the formation of red motile macrozooids. Optimal growth in the green phase was obtained on cultivation under mixotrophic conditions in EG:JM media followed by re-suspension in medium without nitrate resulting in red motile macrozooids with an astaxanthin content of 2.74% (78.4% of total carotenoids and a lipid content of 35.3% (rich in unsaturated fatty acids. It is envisaged that the red motile macrozooids could be harvested and fed as a whole-cell product directly in the animal feed and aquaculture sectors, or used as a blend of carotenoids and polyunsaturated fatty acids (PUFAs in nutraceutical products.

  16. Corrosion Study of Stainless Steels in Peracetic Acid Bleach Media With and Without Chloride and Chelant

    Directory of Open Access Journals (Sweden)

    Rohtash

    2014-12-01

    Full Text Available The paper industries are adopting non-chlorine containing chemicals e.g. peroxide, ozone, peracids etc. as alternate of chlorine based bleach chemicals e.g. chlorine and chlorine dioxide etc. with the aim of eco-friend atmospheres. Changeover to the new chemicals in the bleaching process is likely to affect the metallurgy of the existing bleach plants due to change in the corrosivity of the media. Accordingly, corrosion investigations were performed in a peracid namely peracetic acid to test the suitability of austenitic stainless steels 654SMO, 265SMO, 2205, 317L and 316L. The performance of above stainless steels was evaluated through long term immersion tests and Electrochemical polarization measurements in peracetic acid (PAA bleach media at pH value 4 maintaining concentration 0.2 % as active oxygen along with three chloride levels 0, 500 and 1000 ppm in pulp-free laboratory. To study the effect of corrosion inhibitors with extending limit of chloride in liquors, measurements were also made with two types of chelants- EDTA & MgSO4. The results showed that corrosivity of PAA reduced by addition of chelant while increased with concentration of Cl¯. The results also exhibited that EDTA is better inhibitor than MgSO4.

  17. Dissolution properties of co-amorphous drug-amino acid formulations in buffer and biorelevant media.

    Science.gov (United States)

    Heikkinen, A T; DeClerck, L; Löbmann, K; Grohganz, H; Rades, T; Laitinen, R

    2015-07-01

    Co-amorphous formulations, particularly binary drug-amino acid mixtures, have been shown to provide enhanced dissolution for poorly-soluble drugs and improved physical stability of the amorphous state. However, to date the dissolution properties (mainly intrinsic dissolution rate) of the co-amorphous formulations have been tested only in buffers and their supersaturation ability remain unexplored. Consequently, dissolution studies in simulated intestinal fluids need to be conducted in order to better evaluate the potential of these systems in increasing the oral bioavailability of biopharmaceutics classification system class II drugs. In this study, solubility and dissolution properties of the co-amorphous simvastatin-lysine, gibenclamide-serine, glibenclamide-threonine and glibenclamide-serine-threonine were studied in phosphate buffer pH 7.2 and biorelevant media (fasted and fed state simulated intestinal fluids (FaSSIF and FeSSIF, respectively)). The co-amorphous formulations were found to provide a long-lasting supersaturation and improve the dissolution of the drugs compared to the crystalline and amorphous drugs alone in buffer. Similar improvement, but in lesser extent, was observed in biorelevant media suggesting that a dissolution advantage observed in aqueous buffers may overestimate the advantage in vivo. However, the results show that, in addition to stability advantage shown earlier, co-amorphous drug-amino acid formulations provide dissolution advantage over crystalline drugs in both aqueous and biorelevant conditions.

  18. Enhanced dispersion of boron nitride nanosheets in aqueous media by using bile acid-based surfactants

    Science.gov (United States)

    Chae, Ari; Park, Soo-Jin; Min, Byunggak; In, Insik

    2018-01-01

    Facile noncovalent surface functionalization of hydroxylated boron nitride nanosheet (BNNS-OH) was attempted through the sonication-assisted exfoliation of h-BN in aqueous media in the presence of bile acid-based surfactants such as sodium cholic acid (SC) or sodium deoxycholic acid (SDC), resulting in SC- or SDC-BNNS-OH dispersion with high up to 2 mg ml-1 and enhanced dispersion stability due to the increased negative zeta potential. While prepared SC-BNNS-OH revealed multi-layered BNNS structures, the large lateral sizes of hundreds nanometers and clear h-BN lattice structures are very promising for the preparation and application of water-processable BNNS-based nanomaterials. It is regarded that noncovalent functionalization of BNNS-OH based on σ-π interaction between with σ-rich bile acid-based amphiphiles and π-rich BNNS is very effective to formulate multi-functional BNNS-based nanomaterials or hybrids that can be utilized in various applications where both the pristine properties of BNNS and the extra functions are simultaneously required.

  19. Noble metal catalyzed hydrogen generation from formic acid in nitrite-containing simulated nuclear waste media

    International Nuclear Information System (INIS)

    King, R.B.; Bhattacharyya, N.K.; Wiemers, K.D.

    1994-08-01

    Simulants for the Hanford Waste Vitrification Plant (HWVP) feed containing the major non-radioactive components Al, Cd, Fe, Mn, Nd, Ni, Si, Zr, Na, CO 3 2- , NO 3 -, and NO 2 - were used as media to evaluate the stability of formic acid towards hydrogen evolution by the reaction HCO 2 H → H 2 + CO 2 catalyzed by the noble metals Ru, Rh, and/or Pd found in significant quantities in uranium fission products. Small scale experiments using 40-50 mL of feed simulant in closed glass reactors (250-550 mL total volume) at 80-100 degree C were used to study the effect of nitrite and nitrate ion on the catalytic activities of the noble metals for formic acid decomposition. Reactions were monitored using gas chromatography to analyze the CO 2 , H 2 , NO, and N 2 O in the gas phase as a function of time. Rhodium, which was introduced as soluble RhCl 3 ·3H 2 O, was found to be the most active catalyst for hydrogen generation from formic acid above ∼80 degree C in the presence of nitrite ion in accord with earlier observations. The inherent homogeneous nature of the nitrite-promoted Rh-catalyzed formic acid decomposition is suggested by the approximate pseudo first-order dependence of the hydrogen production rate on Rh concentration. Titration of the typical feed simulants containing carbonate and nitrite with formic acid in the presence of rhodium at the reaction temperature (∼90 degree C) indicates that the nitrite-promoted Rh-catalyzed decomposition of formic acid occurs only after formic acid has reacted with all of the carbonate and nitrite present to form CO 2 and NO/N 2 O, respectively. The catalytic activities of Ru and Pd towards hydrogen generation from formic acid are quite different than those of Rh in that they are inhibited rather than promoted by the presence of nitrite ion

  20. Microsystems for anion exchange separation of radionuclides in nitric acid media

    Energy Technology Data Exchange (ETDEWEB)

    Losno, M.; Brennetot, R.; Mariet, C. [DEN/Service d' Etudes Analytiques et de Reactivite des Surfaces - SEARS, CEA, Centre de Saclay, Universite Paris-Saclay, F-91191, Gif sur Yvette (France); Ferrante, I.; Descroix, S. [MMBM Group, Institut Curie Research Center, CNRS UMR 168, Paris (France)

    2016-07-01

    An efficient and reproducible photo-polymerized poly(ethylene glycol methacrylate methacrylate-co- allyl methacrylate) monolith was synthesized and a photo-grafting process based on the ene-thiol click-chemistry has been performed to give anion exchange properties to the monolith. Since their introduction in the early 1990's polymethacrylate monoliths have emerged as a powerful alternative for microscale separations or sample treatment. Their relatively simple implementation in columns with small internal diameters makes them particularly attractive for the new chromatographic challenges of complex matrices analysis and on-chip separations. Despite their relatively poor ion-exchange capacity due to their highly porous structure, their use as anion exchangers is of large interest for nuclear analysis as numerous separations are based on this process. This paper presents a systematic study of the synthesis of the polymeric porous monolith and the versatile and robust functionalization method developed for the specific strong acidic media used in radiochemical procedures. The robustness of the stationary phase was tested in concentrated nitric acid. It appears that the C-S bond formed via thiol-ene chemistry is strong enough to be used to graft function of interest for separation in strong nitric acid medium. The photo-grafted anion exchanger, a quaternary ammonium, presents sufficient resistance to be used for radionuclide separation in [HNO{sub 3}]=5 mol.L{sup -1}so the next step is its integration in the cyclo olefin copolymer (COC) micro-system.

  1. High-Performance Pyrochlore-Type Yttrium Ruthenate Electrocatalyst for Oxygen Evolution Reaction in Acidic Media

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jaemin [Department; Shih, Pei-Chieh [Department; Tsao, Kai-Chieh [Department; Pan, Yung-Tin [Department; Yin, Xi [Department; Sun, Cheng-Jun [X-ray; Yang, Hong [Department

    2017-08-17

    Development of acid-stable electrocatalysts with low overpotential for oxygen evolution reaction (OER) is a major challenge for the production of hydrogen directly from water. We report in this paper a pyrochlore yttrium ruthenate (Y2Ru2O7-δ) electrocatalyst that has significantly enhanced performance towards OER in acid media over the best-known catalysts, with an onset overpotential of 190 mV and high stability in 0.1-M perchloric acid solution. X-ray absorption near-edge structure (XANES) indicates Y2Ru2O7-δ electrocatalyst had a low valence state that favors the high OER activity. Density functional theory (DFT) calculation shows this pyrochlore has lower band center energy for the overlap between Ru 4d and O 2p orbitals and therefore more stable Ru-O bond than RuO2, highlighting the effect of yttrium on the enhancement in stability. The Y2Ru2O7-δ pyrochlore is also free of expensive iridium metal, thus a cost-effective candidate for practical applications.

  2. Acid-base equilibria and solubility of loratadine and desloratadine in water and micellar media.

    Science.gov (United States)

    Popović, Gordana; Cakar, Mira; Agbaba, Danica

    2009-01-15

    Acid-base equilibria in homogeneous and heterogeneous systems of two antihistaminics, loratadine and desloratadine were studied spectrophotometrically in Britton-Robinson's buffer at 25 degrees C. Acidity constant of loratadine was found to be pK(a) 5.25 and those of desloratadine pK(a1) 4.41 and pK(a2) 9.97. The values of intrinsic solubilities of loratadine and desloratadine were 8.65x10(-6) M and 3.82x10(-4) M, respectively. Based on the pK(a) values and intrinsic solubilities, solubility curves of these two drugs as a function of pH were calculated. The effects of anionic, cationic and non-ionic surfactants applied in the concentration exceeding critical micelle concentration (cmc) on acid-base properties of loratadine and desloratadine, as well as on intrinsic solubility of loratadine were also examined. The results revealed a shift of pK(a) values in micellar media comparing to the values obtained in water. These shifts (DeltapK(a)) ranged from -2.24 to +1.24.

  3. Reactivity of nanoaggregations of platinum on supports of different nature in reactions of catalytic decomposition of hydrazine in acid media

    International Nuclear Information System (INIS)

    Anan'ev, A.V.; Boltoeva, M.Yu.; Grigor'ev, M.S.; Shilov, V.P.; Sharygin, L.M.

    2006-01-01

    Platinized catalysts on the basis of supports of different chemical nature are tested in reactions of catalytic hydrazine decomposition in perchloric and nitric acid solutions. In perchloric acid catalytic activity of catalysts on the basis of ceramic materials of Termoksid brand is higher of activity of catalysts on the basis of amorphous silica gel. In nitric acid solutions opposite dependence is observed. Tendency of ceramic supports to peptization in acid solutions is pointed out. Results obtained are interpreted using conceptions of energetic heterogeneity of surface atoms and hydrazine catalytic decomposition mechanisms in different media [ru

  4. Determination of uranium isotopes in environmental samples by anion exchange in sulfuric and hydrochloric acid media

    International Nuclear Information System (INIS)

    Popov, L.

    2016-01-01

    Method for determination of uranium isotopes in various environmental samples is presented. The major advantages of the method are the low cost of the analysis, high radiochemical yields and good decontamination factors from the matrix elements, natural and man-made radionuclides. The separation and purification of uranium is attained by adsorption with strong base anion exchange resin in sulfuric and hydrochloric acid media. Uranium is electrodeposited on a stainless steel disk and measured by alpha spectrometry. The analytical method has been applied for the determination of concentrations of uranium isotopes in mineral, spring and tap waters from Bulgaria. The analytical quality was checked by analyzing reference materials. - Highlights: • The method allows cost-effective determination of U isotopes. • High amounts of environmental samples can be analyzed. • High chemical yields, energy resolution and decontamination factors were achieved. • Uranium isotope concentrations in mineral waters from Bulgaria are presented.

  5. Review and assessment of technologies for the separation of strontium from alkaline and acidic media

    International Nuclear Information System (INIS)

    Orth, R.J.; Kurath, D.E.

    1994-01-01

    A literature survey has been conducted to identify and evaluate methods for the separation of strontium from acidic and alkaline media as applied to Hanford tank waste. The most promising methods of solvent extraction, precipitation, and ion exchange are described. The following criteria were used for evaluating the separation methods: Appreciable strontium removal must be demonstrated; Strontium selectivity over bulk components must be demonstrated; The method must show promise for evolving into a practical and fairly simple process; The process should be safe to operate; The method must be robust (i.e., capable of separating strontium from various waste types); Secondary waste generation must be minimized; and The method must show resistance to radiation damage. The methods discussed did not necessarily satisfy all of the above criteria; thus, key areas requiring further development are also given for each method. Less promising solvent extraction, precipitation, and ion exchange methods were also identified; areas for potential development are included in this report

  6. Simultaneous determination of amino acids and carbohydrates in culture media of Clostridium thermocellum by valve-switching ion chromatography.

    Science.gov (United States)

    Fa, Yun; Yang, Haiyan; Ji, Chengshuai; Cui, He; Zhu, Xinshu; Du, Juan; Gao, Jun

    2013-10-10

    An improved method for the simultaneous determination of 20 amino acids and 7 carbohydrates using one-valve switching after injection, ion chromatography, and integrated pulsed amperometric detection is proposed. The resolution of the amino acids and carbohydrates in the cation trap column was investigated. In addition, parameters including flow liquid type, flow rate, concentration, and valve-switch timing were optimized. The method is time-saving, effective, and accurate for the simultaneous separation of amino acids and carbohydrates, with a mean correlation coefficient of >0.99 and repeatability of 0.5-4.6% for eight replicates. The method was successfully applied in the analysis of amino acids and carbohydrates in aseptic media and in extracellular culture media of three phenotypes of Clostridium thermocellum. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Inhibitive action of some plant extracts on the corrosion of steel in acidic media

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Gaber, A.M. [Department of Chemistry, Faculty of Science, Alexandria University, Ibrahimia, P.O. Box 426, Alexandria 21321 (Egypt)]. E-mail: ashrafmoustafa@yahoo.com; Abd-El-Nabey, B.A. [Department of Chemistry, Faculty of Science, Alexandria University, Ibrahimia, P.O. Box 426, Alexandria 21321 (Egypt); Sidahmed, I.M. [Department of Chemistry, Faculty of Science, Alexandria University, Ibrahimia, P.O. Box 426, Alexandria 21321 (Egypt); El-Zayady, A.M. [Department of Chemistry, Faculty of Science, Alexandria University, Ibrahimia, P.O. Box 426, Alexandria 21321 (Egypt); Saadawy, M. [Department of Chemistry, Faculty of Science, Alexandria University, Ibrahimia, P.O. Box 426, Alexandria 21321 (Egypt)

    2006-09-15

    The effect of extracts of Chamomile (Chamaemelum mixtum L.), Halfabar (Cymbopogon proximus), Black cumin (Nigella sativa L.), and Kidney bean (Phaseolus vulgaris L.) plants on the corrosion of steel in aqueous 1 M sulphuric acid were investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. EIS measurements showed that the dissolution process of steel occurs under activation control. Potentiodynamic polarization curves indicated that the plant extracts behave as mixed-type inhibitors. The corrosion rates of steel and the inhibition efficiencies of the extracts were calculated. The results obtained show that the extract solution of the plant could serve as an effective inhibitor for the corrosion of steel in sulphuric acid media. Inhibition was found to increase with increasing concentration of the plant extract up to a critical concentration. The inhibitive actions of plant extracts are discussed on the basis of adsorption of stable complex at the steel surface. Theoretical fitting of different isotherms, Langmuir, Flory-Huggins, and the kinetic-thermodynamic model, were tested to clarify the nature of adsorption.

  8. Studies on rapid ion-exchange separation of the transplutonium elements with mineral acid-methanol mixed media

    International Nuclear Information System (INIS)

    Usuda, Shigekazu

    1989-03-01

    In order to study properties of short-lived transplutonium nuclides synthesized by heavy-ion bombardment, three methods for rapid separation of tri-valent transplutonium elements by ion-exchange chromatography with mineral acid-methanol mixed media at elevated temperature were investigated. The first separation method was anion-exchange chromatography with nitric acid-methanol mixed media. The second method was anion-exchange choromatography with dilute hydrochloric acid-methanol mixed media. The third method was improved cation-exchange chromatography with single-column operation using the mixed media of hydrochloric acid and methanol. The separation methods developed were found applicable to studies on synthesis of the trans-plutonium nuclides, 250 Fm (T 1/2 :30 min), 244,245,246 Cf (T 1/2 :20 min, 46 min and 35.7 h, respectively) from the 16 O + 238 U and 12 C + 242 Pu reactions, and on the decay property of 245 Cf. Attempts to search for new actinide nuclides, such as 240 U and neutron deficient nuclides of Am, Cm and Bk, were made by a quick purification. The separation system was also applied to the rapid and effective separation of Nd, Am and Cm from spent nuclear fuel samples, for burn-up determination. (J.P.N.) 242 refs

  9. Reduction of NO adlayers on Pt(110) and Pt(111) in acidic media: evidence for adsorption site-specific reduction

    NARCIS (Netherlands)

    Rosca, V.; Beltramo, G.L.; Koper, M.T.M.

    2005-01-01

    We present a combined in situ Fourier transform infrared reflection-absorption spectroscopy and voltammetric study of the reduction of saturated and subsaturated NO adlayers on Pt(111) and Pt(110) single-crystal surfaces in acidic media. The stripping voltammetry experiments and the associated

  10. Dispersing and stabilizing effect of nonaqueous media with different acid-base functions when preparing process suspensions

    International Nuclear Information System (INIS)

    Koshevar, V.D.; Rat'ko, A.I.; Mironenko, I.N.

    1999-01-01

    Dispersing and stabilizing effect of organic liquids related to the Lewis acids and baser is studied when preparing the suspensions of certain minerals and metal oxides, beryllium oxide, in particular. Practical recommendations are provided for the choice of dispersing media to produce stable suspensions

  11. Single Atomic Iron Catalysts for Oxygen Reduction in Acidic Media: Particle Size Control and Thermal Activation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hanguang; Hwang, Sooyeon; Wang, Maoyu; Feng, Zhenxing; Karakalos, Stavros; Luo, Langli; Qiao, Zhi; Xie, Xiaohong; Wang, Chongmin; Su, Dong; Shao, Yuyan; Wu, Gang (BNL); (Oregon State U.); (SC); (PNNL); (Buffalo)

    2017-09-26

    It remains a grand challenge to replace platinum group metal (PGM) catalysts with earth-abundant materials for the oxygen reduction reaction (ORR) in acidic media, which is crucial for large-scale deployment of proton exchange membrane fuel cells (PEMFCs). Here, we report a high-performance atomic Fe catalyst derived from chemically Fe-doped zeolitic imidazolate frameworks (ZIFs) by directly bonding Fe ions to imidazolate ligands within 3D frameworks. Although the ZIF was identified as a promising precursor, the new synthetic chemistry enables the creation of well-dispersed atomic Fe sites embedded into porous carbon without the formation of aggregates. The size of catalyst particles is tunable through synthesizing Fe-doped ZIF nanocrystal precursors in a wide range from 20 to 1000 nm followed by one-step thermal activation. Similar to Pt nanoparticles, the unique size control without altering chemical properties afforded by this approach is able to increase the number of PGM-free active sites. The best ORR activity is measured with the catalyst at a size of 50 nm. Further size reduction to 20 nm leads to significant particle agglomeration, thus decreasing the activity. Using the homogeneous atomic Fe model catalysts, we elucidated the active site formation process through correlating measured ORR activity with the change of chemical bonds in precursors during thermal activation up to 1100 °C. The critical temperature to form active sites is 800 °C, which is associated with a new Fe species with a reduced oxidation number (from Fe3+ to Fe2+) likely bonded with pyridinic N (FeN4) embedded into the carbon planes. Further increasing the temperature leads to continuously enhanced activity, linked to the rise of graphitic N and Fe–N species. The new atomic Fe catalyst has achieved respectable ORR activity in challenging acidic media (0.5 M H2SO4), showing a half-wave potential of 0.85 V vs RHE and leaving only a 30 mV gap with Pt/C (60 μgPt/cm2). Enhanced stability

  12. Solubility of iron from combustion source particles in acidic media linked to iron speciation.

    Science.gov (United States)

    Fu, Hongbo; Lin, Jun; Shang, Guangfeng; Dong, Wenbo; Grassian, Vichi H; Carmichael, Gregory R; Li, Yan; Chen, Jianmin

    2012-10-16

    In this study, iron solubility from six combustion source particles was investigated in acidic media. For comparison, a Chinese loess (CL) dust was also included. The solubility experiments confirmed that iron solubility was highly variable and dependent on particle sources. Under dark and light conditions, the combustion source particles dissolved faster and to a greater extent relative to CL. Oil fly ash (FA) yielded the highest soluble iron as compared to the other samples. Total iron solubility fractions measured in the dark after 12 h ranged between 2.9 and 74.1% of the initial iron content for the combustion-derived particles (Oil FA > biomass burning particles (BP) > coal FA). Ferrous iron represented the dominant soluble form of Fe in the suspensions of straw BP and corn BP, while total dissolved Fe presented mainly as ferric iron in the cases of oil FA, coal FA, and CL. Mössbauer measurements and TEM analysis revealed that Fe in oil FA was commonly presented as nanosized Fe(3)O(4) aggregates and Fe/S-rich particles. Highly labile source of Fe in corn BP could be originated from amorphous Fe form mixed internally with K-rich particles. However, Fe in coal FA was dominated by the more insoluble forms of both Fe-bearing aluminosilicate glass and Fe oxides. The data presented herein showed that iron speciation varies by source and is an important factor controlling iron solubility from these anthropogenic emissions in acidic solutions, suggesting that the variability of iron solubility from combustion-derived particles is related to the inherent character and origin of the aerosols themselves. Such information can be useful in improving our understanding on iron solubility from combustion aerosols when they undergo acidic processing during atmospheric transport.

  13. Lewis Acid Pairs for the Activation of Biomass-derived Oxygenates in Aqueous Media

    Energy Technology Data Exchange (ETDEWEB)

    Roman, Yuriy [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2015-09-14

    The objective of this project is to understand the mechanistic aspects behind the cooperative activation of oxygenates by catalytic pairs in aqueous media. Specifically, we will investigate how the reactivity of a solid Lewis acid can be modulated by pairing the active site with other catalytic sites at the molecular level, with the ultimate goal of enhancing activation of targeted functional groups. Although unusual catalytic properties have been attributed to the cooperative effects promoted by such catalytic pairs, virtually no studies exist detailing the use heterogeneous water-tolerant Lewis pairs. A main goal of this work is to devise rational pathways for the synthesis of porous heterogeneous catalysts featuring isolated Lewis pairs that are active in the transformation of biomass-derived oxygenates in the presence of bulk water. Achieving this technical goal will require closely linking advanced synthesis techniques; detailed kinetic and mechanistic investigations; strict thermodynamic arguments; and comprehensive characterization studies of both materials and reaction intermediates. For the last performance period (2014-2015), two technical aims were pursued: 1) C-C coupling using Lewis acid and base pairs in Lewis acidic zeolites. Tin-, zirconium-, and hafnium containing zeolites (e.g., Sn-, Zr-, and Hf-Beta) are versatile solid Lewis acids that selectively activate carbonyl functional groups. In this aim, we demonstrate that these zeolites catalyze the cross-aldol condensation of aromatic aldehydes with acetone under mild reaction conditions with near quantitative yields. NMR studies with isotopically labeled molecules confirm that acid-base pairs in the Si-O-M framework ensemble promote soft enolization through α-proton abstraction. The Lewis acidic zeolites maintain activity in the presence of water and, unlike traditional base catalysts, in acidic solutions. 2) One-pot synthesis of MWW zeolite nanosheets for activation of bulky substrates. Through

  14. Pd-catalyzed ethylene methoxycarbonylation with Brønsted acid ionic liquids as promoter and phase-separable reaction media

    DEFF Research Database (Denmark)

    Garcia-Suarez, Eduardo J.; Khokarale, Santosh Govind; Nguyen van Buu, Olivier

    2014-01-01

    Brønsted acid ionic liquids (BAILs) were prepared and applied as combined acid promoters and reaction media in Pd–phosphine catalyzed methoxycarbonylation of ethylene to produce methyl propionate. The BAILs served as alternatives to common mineral acids required for the reaction, e.g. methanesulf......Brønsted acid ionic liquids (BAILs) were prepared and applied as combined acid promoters and reaction media in Pd–phosphine catalyzed methoxycarbonylation of ethylene to produce methyl propionate. The BAILs served as alternatives to common mineral acids required for the reaction, e...

  15. Lipase in biphasic alginate beads as a biocatalyst for esterification of butyric acid and butanol in aqueous media.

    Science.gov (United States)

    Ng, Choong Hey; Yang, Kun-Lin

    2016-01-01

    Esterification of organic acids and alcohols in aqueous media is very inefficient due to thermodynamic constraints. However, fermentation processes used to produce organic acids and alcohols are often conducted in aqueous media. To produce esters in aqueous media, biphasic alginate beads with immobilized lipase are developed for in situ esterification of butanol and butyric acid. The biphasic beads contain a solid matrix of calcium alginate and hexadecane together with 5 mg/mL of lipase as the biocatalyst. Hexadecane in the biphasic beads serves as an organic phase to facilitate the esterification reaction. Under optimized conditions, the beads are able to catalyze the production of 0.16 mmol of butyl butyrate from 0.5 mmol of butyric acid and 1.5 mmol of butanol. In contrast, when monophasic beads (without hexadecane) are used, only trace amount of butyl butyrate is produced. One main application of biphasic beads is in simultaneous fermentation and esterification (SFE) because the organic phase inside the beads is very stable and does not leach out into the culture medium. SFE is successfully conducted with an esterification yield of 6.32% using biphasic beads containing iso-octane even though the solvent is proven toxic to the butanol-producing Clostridium spp. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Voltammetric Perspectives on the Acidity Scale and H+/H2 Process in Ionic Liquid Media.

    Science.gov (United States)

    Bentley, Cameron L; Bond, Alan M; Zhang, Jie

    2018-03-19

    Nonhaloaluminate ionic liquids (ILs) have received considerable attention as alternatives to molecular solvents in diverse applications spanning the fields of physical, chemical, and biological science. One important and often overlooked aspect of the implementation of these designer solvents is how the properties of the IL formulation affect (electro)chemical reactivity. This aspect is emphasized herein, where recent (voltammetric) studies on the energetics of proton (H + ) transfer and electrode reaction mechanisms of the H + H 2 process in IL media are highlighted and discussed. The energetics of proton transfer, quantified using the pK 3 a (minus logarithm of acidity equilibrium constant, K a ) formalism, is strongly governed by the constituent IL anion, and to a lesser extent, the IL cation. The H + /H 2 process, a model inner-sphere reaction, also displays electrochemical characteristics that are strongly IL-dependent. Overall, these studies highlight the need to carry out systematic investigations to resolve IL structure and function relationships in order to realize the potential of these diverse and versatile solvents. Expected final online publication date for the Annual Review of Analytical Chemistry Volume 11 is June 12, 2018. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

  17. Study of oxidation-reduction reactions of plutonium and neptunium in sulphuric-phosphoric acid media

    International Nuclear Information System (INIS)

    Moiseev, I.V.; Kuperman, A.Ya.; Borodina, N.N.; Galkina, V.N.; Vinokurov, V.A.

    1976-01-01

    Potentiostatic, coulometric, potentiometric, and amperometric methods have been used for determining the rate constants of disproportionation (ksub(d)) of plutonium(5) and neptunium (5) and normal real redox potentials (Esub(0)sup(p)) of the following ion pairs in sulphur-phosphoric-acid media: PuOsub(2)sup(2)sup(+) (PuO 2 + , Pu 4+ /Pu 3+ , NpO 2 2+ /NpO 2 + , NpO 2 2+ /Np 4+ , NpO 2 + /Np 4+ , and Fe 3+ /Fe 2+ . The regularities have been shown of changing ksub(d) and Esub(o)sup(p) as a function of H 2 SO 4 and H 3 PO 4 concentration. It has been established that for plutonium and neptunium a linear correlation is observed between lg ksub(d) and Esub(o)sup(p) of the ion pairs NpO 2 2+ /NpO 2 + , NpO 2 2 /Np 4+ , NpO 2 + /Np 4+ and PuO 2 2+ /PuO 2 + in a wide range of their values. The correlation coefficient is close to unity in all cases (no less than 0.96). The results of investigations have made it possible to recommend optimum compositions of background electrolytes for performing continuous amperostatic coulometric titration of Pusup((6)) and Npsup((6)) up to four valent state by electrogenerated ions of iron (2)

  18. Evaluation of culture media for selective enumeration of bifidobacteria and lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    Judit Süle

    2014-09-01

    Full Text Available The purpose of this study was to test the suitability of Transgalactosylated oligosaccharides-mupirocin lithium salt (TOS-MUP and MRS-clindamycin-ciprofloxacin (MRS-CC agars, along with several other culture media, for selectively enumerating bifidobacteria and lactic acid bacteria (LAB species commonly used to make fermented milks. Pure culture suspensions of a total of 13 dairy bacteria strains, belonging to eight species and five genera, were tested for growth capability under various incubation conditions. TOS-MUP agar was successfully used for the selective enumeration of both Bifidobacterium animalis subsp. lactis BB-12 and B. breve M-16 V. MRS-CC agar showed relatively good selectivity for Lactobacillus acidophilus, however, it also promoted the growth of Lb. casei strains. For this reason, MRS-CC agar can only be used as a selective medium for the enumeration of Lb. acidophilus if Lb. casei is not present in a product at levels similar to or exceeding those of Lb. acidophilus. Unlike bifidobacteria and coccus-shaped LAB, all the lactobacilli strains involved in this work were found to grow well in MRS pH 5.4 agar incubated under anaerobiosis at 37 °C for 72 h. Therefore, this method proved to be particularly suitable for the selective enumeration of Lactobacillus spp.

  19. Zirconia sol-gel coatings deposited on 304 stainless steel for chemical protection in acid media

    International Nuclear Information System (INIS)

    Luna, F. Perdomo; Atik, M.; Avaca, Luis A.; Aegerter, M.A.

    1995-01-01

    Zr O 2 thin films were prepared by sol-gel method and using dip-coating technique for deposition on 304 austenitic stainless steel, from sonocatalyzed sols of zirconia alkoxide, isopropanol (Zr(O C 3 H 7 )4/C 3 H 7 OH = 0.5), glacial acetic acid and water (C H 3 CO OH/H 2 O = 0.5). The films were dried at 40 deg C/15 min and thermally treated in the air with a linear variation of 5 deg C/min and two isothermal holdings at 400 deg C during 1 h and afterwards at 800 deg C during several periods of time (up to 20 h). The film thickness ranges between 0.6 and 0.8 μm. Structure and morphology were studied by x-ray diffraction and scanning electron microscopy. The corrosion potential, the corrosion current density, the polarization resistance and the corrosion rate (mpy) in 1,0 N aqueous solution of H 2 SO 4 at room temperature were determined using potentiometric polarization curves with a scanning velocity of 1 mV/s. These films act as a blocking physical layer in the corrosion media and increase the substrate life time in a factor of 7

  20. Electrochemical evaluation of inhibition efficiency of ciprofloxacin on the corrosion of copper in acid media

    Energy Technology Data Exchange (ETDEWEB)

    Thanapackiam, P. [Department of Chemistry, Coimbatore Institute of Technology, Coimbatore, Tamilnadu, 641 014 (India); Rameshkumar, Subramaniam [Department of Chemistry, Sri Vasavi College, Erode, Tamilnadu, 638 316 (India); Subramanian, S.S. [Department of Chemistry, PSG College of Technology, Coimbatore, Tamilnadu, 641 004 (India); Mallaiya, Kumaravel, E-mail: mkvteam.research@gmail.com [Department of Chemistry, PSG College of Technology, Coimbatore, Tamilnadu, 641 004 (India)

    2016-05-01

    The inhibition efficiency of ciprofloxacin on the corrosion of copper was studied in 1.0MHNO{sub 3} and 0.5MH{sub 2}SO{sub 4} solutions by electrochemical impedance spectroscopy and potentiodynamic polarization techniques. The corrosion inhibition action of ciprofloxacin was observed to be of mixed type in both the acid media, but with more of a cathodic nature. The experimental data were found to fit well with the Langmuir adsorption isotherm. The thermodynamic parameters such as adsorption equilibrium constant(K{sub ads}), free energy of adsorption(ΔG{sub ads}), activation energy(E{sub a}) and potential of zero charge(PZC) showed that the adsorption of ciprofloxacin onto copper surface involves both physisorption and chemisorption. - Highlights: • The inhibitor efficiency increases with increase in ciprofloxacin concentration. • Polarization measurements show that ciprofloxacin acts as a mixed type inhibitor. • The adsorption of the inhibitor on copper surface follows Langmuir adsorption isotherm. • The negative values of ΔG{sub ads} indicates that the adsorption is spontaneous and exothermic.

  1. Zirconia sol-gel coatings deposited on 304 stainless steel for chemical protection in acid media

    Energy Technology Data Exchange (ETDEWEB)

    Luna, F Perdomo; Atik, M; Avaca, Luis A; Aegerter, M A [Sao Paulo Univ., Sao Carlos, SP (Brazil). Inst. de Fisica

    1996-12-31

    Zr O{sub 2} thin films were prepared by sol-gel method and using dip-coating technique for deposition on 304 austenitic stainless steel, from sonocatalyzed sols of zirconia alkoxide, isopropanol (Zr(O C{sub 3} H{sub 7})4/C{sub 3} H{sub 7} OH = 0.5), glacial acetic acid and water (C H{sub 3} CO OH/H{sub 2} O = 0.5). The films were dried at 40 deg C/15 min and thermally treated in the air with a linear variation of 5 deg C/min and two isothermal holdings at 400 deg C during 1 h and afterwards at 800 deg C during several periods of time (up to 20 h). The film thickness ranges between 0.6 and 0.8 {mu}m. Structure and morphology were studied by x-ray diffraction and scanning electron microscopy. The corrosion potential, the corrosion current density, the polarization resistance and the corrosion rate (mpy) in 1,0 N aqueous solution of H{sub 2} SO{sub 4} at room temperature were determined using potentiometric polarization curves with a scanning velocity of 1 mV/s. These films act as a blocking physical layer in the corrosion media and increase the substrate life time in a factor of 7 16 refs., 3 figs., 1 tab.

  2. Use of Nonspecific, Glutamic Acid-Free, Media and High Glycerol or High Amylase as Inducing Parameters for Screening Bacillus Isolates Having High Yield of Polyglutamic Acid.

    Science.gov (United States)

    Baxi, Nandita N

    2014-01-01

    Out of fifty-five Bacillus isolates obtained from ten different regional locations and sources, seven showed the ability to consistently produce specific extracellular polymeric substance (EPS) on rich as well as synthetic but nonspecific media which did not contain glutamic acid. The isolates were identified as either Bacillus licheniformis or Bacillus subtilis. The EPS from all isolates was resistant to alpha protease, proteinase K, and was thus of high molecular weight. Further it was detected after SDS-PAGE by methylene blue but not by coomassie blue R staining as in case of proteins with high proportion of acidic amino acids. Cell-free EPS, after acid hydrolysis, showed absence of carbohydrates and presence of only glutamic acid. Thus the native the EPS from all seven isolates was confirmed to be gamma polyglutamic acid (PGA) and not exopolysaccharide. The Bacillus isolate T which produced maximum polymer on all media tested had higher amylase: protease activity as compared to other strains. If inoculum was developed in rich medium as compared to synthetic medium, the PGA produced increased by twofold in the subsequent synthetic production medium. Similarly, use of inoculum consisting of young and vegetative cells also increased the PGA production by twofold though amount of inoculum did not affect yield of PGA. Though PGA was produced in even in the absence of glutamic acid supplementation in the production medium by all isolates, the yield of PGA increased by fourfold in the presence glutamic acid and the maximum yield was 30 g/l for isolate K. The supplementation of glutamine instead of glutamic acid into the medium caused an increase in the viscosity of the non-Newtonian solution of PGA.

  3. Study of vanadium(IV) species and corresponding electrochemical performance in concentrated sulfuric acid media

    International Nuclear Information System (INIS)

    Wu Xuewen; Wang Jinjin; Liu Suqin; Wu Xiongwei; Li Sha

    2011-01-01

    Highlights: → Two new UV/Vis absorbance peaks are found in V(IV) sulfuric acid solutions. → We give the structural information on the new corresponding V(IV) species. → Reaction route is given with increasing sulfuric acid and V(IV) concentrations. → We find V(IV) species corresponding to the reversible electrochemical reaction. → A mixed-valence intermediate is invoked in the reversible reaction. - Abstract: The vanadium(IV) ion is found to form the [VO(SO 4 )(H 2 O) 4 ].H 2 O complex, as well as the dimer, [VO(H 2 O) 3 ] 2 (μ-SO 4 ) 2 , in concentrated H 2 SO 4 media. Their formation mechanisms were investigated by UV-Visible spectroscopy (UV-Vis), Raman spectroscopy, X-ray diffraction (XRD), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). UV-Vis spectroscopy study showed that [VO(SO 4 )(H 2 O) 4 ].H 2 O concentration in H 2 SO 4 solution was proportional to concentrations of VO 2+ and SO 4 2- . The increased deviation from the near centrosymmetry of the octahedral complexes is due to the replacement of an equatorial water oxygen in [VO(H 2 O) 5 ]SO 4 by a sulfate oxygen in [VO(SO 4 )(H 2 O) 4 ].H 2 O. The dimer shows symmetrical structure, which correlates very well with non-activity in UV-Vis spectroscopic analysis. Structural information on both vanadium(IV) species can be confirmed by Raman and XRD measurements of crystals from the supersaturated solution of VOSO 4 in 1 M, 6 M and 12 M sulfuric acid. A solution of vanadium(IV) (0.05 M) in 12 M H 2 SO 4 , in which the vanadium(IV) species is [VO(H 2 O) 3 ] 2 (μ-SO 4 ) 2 , exhibits a reversible redox behavior near 1.14 V (vs. SCE) on the carbon paper electrode.

  4. The kinetics and mechanism of methanol oxidation on Pt and PtRu catalysts in alkaline and acid media

    Directory of Open Access Journals (Sweden)

    JELENA LOVIC

    2007-07-01

    Full Text Available The kinetic of methanol electrochemical oxidation for a series of platinum and platinum–ruthenium catalysts was investigated. A correlation between the beginning of OHad adsorption and methanol oxidation was demonstarated on Pt single crystals and Pt nanocatalyst. The activity of the nano-structured Pt catalyst was compared with single crystal platinum electrodes assuming the Kinoshita model of nanoparticles. The ruthenium-containing catalysts shifted the onset of methanol oxidation to more negative potentials. The effect was more pronounced in acid than in alkaline media. Based on the established diagnostic criteria, the reaction between COad and OHad species according to the Langmuir–Hinshelwood mechanism was proposed as the rate determining step in alkaline and acid media on Pt and PtRu catalysts.

  5. Anion exchange separation of the light lanthanoids with nitric acid-methyl alcohol mixed media at elevated temperature

    International Nuclear Information System (INIS)

    Usuda, S.; Magara, M.

    1987-01-01

    Anion exchange chromatography with nitric acid-methyl alcohol mixed media at elevated temperature was applied to mutual separation of the light lanthanoids, La, Ce, Pr, Nd and Pm. The individual elements could be effectively separated from each other, main fission products and actinoids with 0.01M HNO 3 -90% CH 3 OH or 0.5M HNO 3 -80% CH 3 OH eluent at 90 deg C. (author) 14 refs.; 3 tables

  6. The study of interaction of modified fatty acid with {sup 99m}Tc in alcoholic media

    Energy Technology Data Exchange (ETDEWEB)

    Skuridin, V. S.; Stasyuk, E. S.; Varlamova, N. V.; Nesterov, E. A.; Sadkin, V. L.; Rogov, A. S., E-mail: rogov@tpu.ru; Ilina, E. A.; Larionova, L. A.; Villa, N. E. [Institute of Physics and Technology, Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Sinilkin, I. G.; Zelchan, R. V. [Institute of Physics and Technology, Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Tomsk Cancer Research Institute, Tomsk, 634050 (Russian Federation); Sazonova, S. I. [Institute of Physics and Technology, Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Research Institute of Cardiology, Tomsk, 634012 (Russian Federation)

    2016-08-02

    The paper presents the results of laboratory research aimed at the development of methods of synthesis of new radiodiagnostic agents based on modified fatty acid labelled with technetium-99m intended for scintigraphic evaluation of myocardial metabolism. In particular, the interaction of substance with {sup 99m}Tc in alcoholic media and the use of ethanol as solvent in the synthesis of the radiopharmaceutical were studied.

  7. Separation of DR synthesized Ti-Mg Alloy by dissolution of waste by-products in acid media

    CSIR Research Space (South Africa)

    Mushove, T

    2010-06-01

    Full Text Available Of DR Synthesized Ti-Mg Alloy By Dissolution Of Waste By-Products In Acid Media. The dissolution experiments were done in a Julabo SW23 waterbath shaker, with 300 ml flasks. Acid solution of predetermined molarity was charged into a flask and heated... of the diffraction peaks of Mg and TiO2. The reduction of TiO2 at 32hrs of milling was evaluated from Equation 6.2 to be 90.4% (4). Calculated proportions of products, and the respective masses from a 2g sample, are shown in Table 1. Constituent TiO2 Ti-Mg Mg...

  8. Kinetic analysis of strains of lactic acid bacteria and acetic acid bacteria in cocoa pulp simulation media toward development of a starter culture for cocoa bean fermentation.

    Science.gov (United States)

    Lefeber, Timothy; Janssens, Maarten; Camu, Nicholas; De Vuyst, Luc

    2010-12-01

    The composition of cocoa pulp simulation media (PSM) was optimized with species-specific strains of lactic acid bacteria (PSM-LAB) and acetic acid bacteria (PSM-AAB). Also, laboratory fermentations were carried out in PSM to investigate growth and metabolite production of strains of Lactobacillus plantarum and Lactobacillus fermentum and of Acetobacter pasteurianus isolated from Ghanaian cocoa bean heap fermentations, in view of the development of a defined starter culture. In a first step, a selection of strains was made out of a pool of strains of these LAB and AAB species, obtained from previous studies, based on their fermentation kinetics in PSM. Also, various concentrations of citric acid in the presence of glucose and/or fructose (PSM-LAB) and of lactic acid in the presence of ethanol (PSM-AAB) were tested. These data could explain the competitiveness of particular cocoa-specific strains, namely, L. plantarum 80 (homolactic and acid tolerant), L. fermentum 222 (heterolactic, citric acid fermenting, mannitol producing, and less acid tolerant), and A. pasteurianus 386B (ethanol and lactic acid oxidizing, acetic acid overoxidizing, acid tolerant, and moderately heat tolerant), during the natural cocoa bean fermentation process. For instance, it turned out that the capacity to use citric acid, which was exhibited by L. fermentum 222, is of the utmost importance. Also, the formation of mannitol was dependent not only on the LAB strain but also on environmental conditions. A mixture of L. plantarum 80, L. fermentum 222, and A. pasteurianus 386B can now be considered a mixed-strain starter culture for better controlled and more reliable cocoa bean fermentation processes.

  9. Kinetic Analysis of Strains of Lactic Acid Bacteria and Acetic Acid Bacteria in Cocoa Pulp Simulation Media toward Development of a Starter Culture for Cocoa Bean Fermentation ▿

    Science.gov (United States)

    Lefeber, Timothy; Janssens, Maarten; Camu, Nicholas; De Vuyst, Luc

    2010-01-01

    The composition of cocoa pulp simulation media (PSM) was optimized with species-specific strains of lactic acid bacteria (PSM-LAB) and acetic acid bacteria (PSM-AAB). Also, laboratory fermentations were carried out in PSM to investigate growth and metabolite production of strains of Lactobacillus plantarum and Lactobacillus fermentum and of Acetobacter pasteurianus isolated from Ghanaian cocoa bean heap fermentations, in view of the development of a defined starter culture. In a first step, a selection of strains was made out of a pool of strains of these LAB and AAB species, obtained from previous studies, based on their fermentation kinetics in PSM. Also, various concentrations of citric acid in the presence of glucose and/or fructose (PSM-LAB) and of lactic acid in the presence of ethanol (PSM-AAB) were tested. These data could explain the competitiveness of particular cocoa-specific strains, namely, L. plantarum 80 (homolactic and acid tolerant), L. fermentum 222 (heterolactic, citric acid fermenting, mannitol producing, and less acid tolerant), and A. pasteurianus 386B (ethanol and lactic acid oxidizing, acetic acid overoxidizing, acid tolerant, and moderately heat tolerant), during the natural cocoa bean fermentation process. For instance, it turned out that the capacity to use citric acid, which was exhibited by L. fermentum 222, is of the utmost importance. Also, the formation of mannitol was dependent not only on the LAB strain but also on environmental conditions. A mixture of L. plantarum 80, L. fermentum 222, and A. pasteurianus 386B can now be considered a mixed-strain starter culture for better controlled and more reliable cocoa bean fermentation processes. PMID:20889778

  10. Oxidative decarboxylation of glycolic and phenylacetic acids with cerium(4) catalyzed by silver ions in the sulfuric acid media

    International Nuclear Information System (INIS)

    Venkatesvar Rao, G.; Nagardzhun Rao, Ch.; Sajprakash, P.K.

    1981-01-01

    Oxidative decarboxylation of glycolic and phenylacetic acids by cerium (4) in the presence of Ag + ions is studied. The Ce(4) order equals 1, glycolic acid order in the absence of a catalyst also equals 1 and is fractional (0.5) for a catalytic reaction. The phenylacetic acid order is fractional (0.75). The Ag + ion reaction order is fractional and constitutes 0.32 for glycolic and 0.36 for phenylacetic acids. The reaction mechanism is proposed [ru

  11. Providing theoretical data for detection of four formamidic acid isomers in astrophysical media

    Science.gov (United States)

    Vichietti, R. M.; da Silva, A. B. F.; Haiduke, R. L. A.

    2018-03-01

    We present a theoretical study, so that molecular data (geometrical parameters, vibrational frequencies, infrared intensities, electronic energies, enthalpies, and Gibbs energies) of four formamidic acid (FA) isomers (labeled here as FA1, FA2, FA3, and FA4) and formamide (HCONH2) are obtained from CCSD/cc-pVTZ, CCSD/aug-cc-pVTZ, CCSD/cc-pVQZ, and CCSD(T)/cc-pVTZ calculations. Furthermore, on the basis of insufficient or even lacking theoretical and experimental results in the literature, we employed the aforementioned theory levels to determine benchmark values of dipole moments and rotational constants for these four FA isomers in order to contribute for their detection in astrophysical environments. Besides, we provide for the first time data about forward and reverse rate constants (200-4000 K) and Arrhenius' parameters for each interconversion reaction between pairs of FA isomers as well as for the tautomeric process involving FA4 and formamide, which were calculated from a Complete Basis Set (CBS) extrapolation equation obtained at CCSD/cc-pVTZ optimized geometries. Our kinetic analysis indicated a faster interconversion between the FA structures in comparison with the FA4 ↔ HCONH2 process, suggesting that these isomers could co-exist in astrophysical media. Finally, we estimated that these isomers may be detected with relative abundances, [FAx]/[HCONH2] (x = 1, 2, 3, and 4), between ∼0.01 and ∼0.1% in astrophysical sources at chemical equilibrium conditions and temperatures around 1000 K. However, these ratios can become as high as ∼1, ∼3, and ∼5%, respectively, in hotter regions with temperatures around 2000, 3000, and 4000 K (expected, for example, in massive star-forming regions).

  12. Facilitated transport of titanium dioxide nanoparticles by humic substances in saturated porous media under acidic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ruichang [Chinese Academy of Sciences, Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science (China); Zhang, Haibo; Tu, Chen; Hu, Xuefeng; Li, Lianzhen [Chinese Academy of Sciences, Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (China); Luo, Yongming, E-mail: ymluo@yic.ac.cn; Christie, Peter [Chinese Academy of Sciences, Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science (China)

    2015-04-15

    The transport behavior of titanium dioxide nanoparticles (TiO{sub 2} NPs, 30 nm in diameter) was studied in well-defined porous media composed of clean quartz sand over a range of solution chemistry under acidic conditions. Transport of TiO{sub 2} NPs was dramatically enhanced by humic substances (HS) at acidic pH (4.0, 5.0 and 6.0), even at a low HS concentration of 0.5 mg L{sup −1}. Facilitated transport of TiO{sub 2} NPs was likely attributable to the increased stability of TiO{sub 2} NPs and repulsive interaction between TiO{sub 2} NPs and quartz sands due to the adsorbed HS. The mobility of TiO{sub 2} NPs was also increased with increasing pH from 4.0 to 6.0. Although transport of TiO{sub 2} NPs was insensitive to low ionic strength, it was significantly inhibited by high concentrations of NaCl and CaCl{sub 2}. In addition, calculated Derjaguin–Landau–Verwey–Overbeek (DLVO) interaction energy indicated that high energy barriers were responsible for the high mobility of TiO{sub 2} NPs, while the secondary energy minimum could play an important role in the retention of TiO{sub 2} NPs at 100 mmol L{sup −1} NaCl. Straining and gravitational settlement of larger TiO{sub 2} NPs aggregates at 1 mg L{sup −1} HS, pH 5.0, and 2 mmol L{sup −1} CaCl{sub 2} could be responsible for the significant retention even in the presence of high energy barriers. Moreover, more favorable interaction between approaching TiO{sub 2} NPs and TiO{sub 2} NPs that had been already deposited on the collector resulted in a ripening-shape breakthrough curve at 2 mmol L{sup −1} CaCl{sub 2}. Overall, a combination of mechanisms including DLVO-type force, straining, and physical filtration was involved in the retention of TiO{sub 2} NPs over the range of solution chemistry examined in this study.

  13. Kinetic and Mechanistic Studies of Oxidation of an Antiallergic Drug with Bromamine-T in Acid and Alkaline Media

    International Nuclear Information System (INIS)

    Puttaswamy; Anu Sukhdev

    2012-01-01

    Cetrizine dihydrochloride (CTZH) is widely used as an anti-allergic drug. Sodium N-bromo-p-toluenesulfonamide or bromamine-T (BAT) is the bromine analogue of chloramine-T (CAT) and is found to be a better oxidizing agent than CAT. In the present research, the kinetics of oxidation of CTZH with BAT in acid and alkaline media was studied at 313 K. The experimental rate laws obtained are: -d[BAT]/dt = k[BAT] [CTZH] 0.80 [H + ] -0.48 in acid medium and -d[BAT]/dt = k[BAT][CTZH] 0.48 [OH - ] 0.52 [PTS] -0.40 in alkaline medium where PTS is p-toluenesulfonamide. Activation parameters and reaction constants were evaluated. The solvent isotope effect was studied using D 2 O. The dielectric effect is positive. The stoichiometry of the reaction was found to be 1:1 and the oxidation products were identified as 4-chlorobenzophenone and (2-piperazin-1-yl-ethoxy)-acetic acid in both media. The rate of oxidation of CTZH is faster in acid medium. Suitable mechanisms and related rate laws have been worked out

  14. An efficient protocol for incorporation of an unnatural amino acid in perdeuterated recombinant proteins using glucose-based media

    Energy Technology Data Exchange (ETDEWEB)

    Venditti, Vincenzo; Fawzi, Nicolas L.; Clore, G. Marius, E-mail: mariusc@mail.nih.gov [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States)

    2012-03-15

    The in vivo incorporation of unnatural amino acids into proteins is a well-established technique requiring an orthogonal tRNA/aminoacyl-tRNA synthetase pair specific for the unnatural amino acid that is incorporated at a position encoded by a TAG amber codon. Although this technology provides unique opportunities to engineer protein structures, poor protein yields are usually obtained in deuterated media, hampering its application in the protein NMR field. Here, we describe a novel protocol for incorporating unnatural amino acids into fully deuterated proteins using glucose-based media (which are relevant to the production, for example, of amino acid-specific methyl-labeled proteins used in the study of large molecular weight systems). The method consists of pre-induction of the pEVOL plasmid encoding the tRNA/aminoacyl-tRNA synthetase pair in a rich, H{sub 2}O-based medium prior to exchanging the culture into a D{sub 2}O-based medium. Our protocol results in high level of isotopic incorporation ({approx}95%) and retains the high expression level of the target protein observed in Luria-Bertani medium.

  15. Hydrometallurgical process for the recovery of metal values from spent lithium-ion batteries in citric acid media.

    Science.gov (United States)

    Chen, Xiangping; Zhou, Tao

    2014-11-01

    In this paper, a hydrometallurgical process has been proposed to recover valuable metals from spent lithium-ion batteries in citric acid media. Leaching efficiencies as high as 97%, 95%, 94%, and 99% of Ni, Co, Mn, and Li were achieved under the optimal leaching experimental conditions of citric acid concentration of 2 mol L(-1), leaching temperature of 80 °C, leaching time of 90 min, liquid-solid ratio of 30 ml g(-1), and 2 vol. % H2O2. For the metals recovery process, nickel and cobalt were selectively precipitated by dimethylglyoxime reagent and ammonium oxalate sequentially. Then manganese was extracted by Na-D2EHPA and the manganese-loaded D2EHPA was stripped with sulfuric acid. The manganese was recovered as MnSO4 in aqueous phase and D2EHPA could be reused after saponification. Finally, lithium was precipitated by 0.5 mol L(-1) sodium phosphate. Under their optimal conditions, the recovery percentages of Ni, Co, Mn, and Li can reach 98%, 97%, 98%, and 89%, respectively. This is a relatively simple route in which all metal values could be effectively leached and recovered in citric acid media. © The Author(s) 2014.

  16. Kinetic and Mechanistic Studies of Oxidation of an Antiallergic Drug with Bromamine-T in Acid and Alkaline Media

    Energy Technology Data Exchange (ETDEWEB)

    Puttaswamy; Anu Sukhdev [Bangalore Univ., Bangalore (India)

    2012-11-15

    Cetrizine dihydrochloride (CTZH) is widely used as an anti-allergic drug. Sodium N-bromo-p-toluenesulfonamide or bromamine-T (BAT) is the bromine analogue of chloramine-T (CAT) and is found to be a better oxidizing agent than CAT. In the present research, the kinetics of oxidation of CTZH with BAT in acid and alkaline media was studied at 313 K. The experimental rate laws obtained are: -d[BAT]/dt = k[BAT] [CTZH]{sup 0.80}[H{sup +}]{sup -0.48} in acid medium and -d[BAT]/dt = k[BAT][CTZH]{sup 0.48}[OH{sup -}]{sup 0.52}[PTS]{sup -0.40} in alkaline medium where PTS is p-toluenesulfonamide. Activation parameters and reaction constants were evaluated. The solvent isotope effect was studied using D{sub 2}O. The dielectric effect is positive. The stoichiometry of the reaction was found to be 1:1 and the oxidation products were identified as 4-chlorobenzophenone and (2-piperazin-1-yl-ethoxy)-acetic acid in both media. The rate of oxidation of CTZH is faster in acid medium. Suitable mechanisms and related rate laws have been worked out.

  17. Synthesis and corrosion inhibition application of NATN on mild steel surface in acidic media complemented with DFT studies

    Directory of Open Access Journals (Sweden)

    Shaimaa B. Al-Baghdadi

    2018-03-01

    Full Text Available The corrosion inhibition effectiveness of thiosemicarbazide compound, namely 3-nitro-5-(2-amino-1,3,4-thiadiazolylnitrobenzene (NATN, on mild steel in 1 M hydrochloric acid media has been investigated by weight loss technique. The results exhibit that the corrosion ratio of mild steel was reduced regarding to adding NATN. The corrosion inhibition rate for the NATN was 92.3% at the highest investigated NATN concentration. From the weight loss results it could be concluded that NATN with sulfur, nitrogen and oxygen atoms has clarified best corrosion inhibition achievement comparing to 3,5-dinitrobenzoic acid. Regarding to theoretical studies, DFT was employee to figured geometrical structure and electronic characteristics on NATN. The investigation have been extensive to the HOMO and LUMO analysis to evaluate the energy gap, Ionization potential, Electron Affinity, Global Hardness, Chemical Potential, Electrophilicity, Electronegativity and Polarizability. Keywords: NATN, Mild steel, Weight loss, Dinitrobenzoic acid

  18. CRASH-2 Study of Tranexamic Acid to Treat Bleeding in Trauma Patients: A Controversy Fueled by Science and Social Media.

    Science.gov (United States)

    Binz, Sophia; McCollester, Jonathon; Thomas, Scott; Miller, Joseph; Pohlman, Timothy; Waxman, Dan; Shariff, Faisal; Tracy, Rebecca; Walsh, Mark

    2015-01-01

    This paper reviews the application of tranexamic acid, an antifibrinolytic, to trauma. CRASH-2, a large randomized controlled trial, was the first to show a reduction in mortality and recommend tranexamic acid use in bleeding trauma patients. However, this paper was not without controversy. Its patient recruitment, methodology, and conductance in moderate-to-low income countries cast doubt on its ability to be applied to trauma protocols in countries with mature trauma networks. In addition to traditional vetting in scientific, peer-reviewed journals, CRASH-2 came about at a time when advances in communication technology allowed debate and influence to be leveraged in new forms, specifically through the use of multimedia campaigns, social media, and Internet blogs. This paper presents a comprehensive view of tranexamic acid utilization in trauma from peer-reviewed evidence to novel multimedia influences.

  19. Cyclic voltammetric study of electro-oxidation of methanol on platinum electrode in acidic and neutral media

    International Nuclear Information System (INIS)

    Khan, A.S.A.; Ahmed, R.; Mirza, M.L.

    2007-01-01

    The electro-oxidation of methanol on electrochemically treated platinum foil was investigated in acidic and neutral media for comparison of cyclic voltammetric characteristics and elucidation of mechanism of electro-oxidation of methanol. The surface area and roughness factor of platinum electrode was calculated. The electro-oxidation of mathanol is an irreversible process giving. anodic peaks in both anodic and cathodic sweep. The characteristic peaks of electrooxidation of methanol appeared at almost the same potential region in both acidic and neutral media. In neutral medium, certain additional cathodic/anodic peaks appeared which were confirmed to arise by the reduction/oxidation of hydrogen ions. The exchange current density and heterogeneous electron transfer rate constant was higher in neutral medium as. compared with acidic medium. The thermodynamic parameters delta H, delta S, and delta G/sub 298/ were calculated. The values of delta H and delta G/sub 298/were positive which indicated that the process of electro-oxidation of methanol is an endothermic and nonspontaneous. The mechanism of electro-oxidation of methanol was same in both acidic and neutral media involving the formation of various adsorbed intermediate species through dissociative adsorption steps leading to the formation of Co adsorbed radicals, which are removed. during interaction with adsorbed hydrous oxides provided by the oxidation of adsorbed water molecules. The higher rate of electro-oxidation of methanol in neutral medium was interpreted in the tight of electrochemical mechanism and was attributed to the presence of comparatively small amount of hydrogen ions only along the surface of working electrode, which are produced during electro-oxidation of methanol. (author)

  20. Fundamental Mechanistic Understanding of Electrocatalysis of Oxygen Reduction on Pt and Non-Pt Surfaces: Acid versus Alkaline Media

    Directory of Open Access Journals (Sweden)

    Nagappan Ramaswamy

    2012-01-01

    Full Text Available Complex electrochemical reactions such as Oxygen Reduction Reaction (ORR involving multi-electron transfer is an electrocatalytic inner-sphere electron transfer process that exhibit strong dependence on the nature of the electrode surface. This criterion (along with required stability in acidic electrolytes has largely limited ORR catalysts to the platinum-based surfaces. New evidence in alkaline media, discussed here, throws light on the involvement of surface-independent outer-sphere electron transfer component in the overall electrocatalytic process. This surface non-specificity gives rise to the possibility of using a wide-range of non-noble metal surfaces as electrode materials for ORR in alkaline media. However, this outer-sphere process predominantly leads only to peroxide intermediate as the final product. The importance of promoting the electrocatalytic inner-sphere electron transfer by facilitation of direct adsorption of molecular oxygen on the active site is emphasized by using pyrolyzed metal porphyrins as electrocatalysts. A comparison of ORR reaction mechanisms between acidic and alkaline conditions is elucidated here. The primary advantage of performing ORR in alkaline media is found to be the enhanced activation of the peroxide intermediate on the active site that enables the complete four-electron transfer. ORR reaction schemes involving both outer- and inner-sphere electron transfer mechanisms are proposed.

  1. Maleic acid and aluminum chloride catalyzed conversion of glucose to 5-(hydroxymethyl) furfural and levulinic acid in aqueous media

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ximing [Laboratory of Renewable Resources Engineering and Department of Agricultural and Biological Engineering; Purdue University; West Lafayette; USA; The Center for Direct Catalytic Conversion of Biomass to Biofuels (C3Bio); Murria, Priya [The Center for Direct Catalytic Conversion of Biomass to Biofuels (C3Bio); Discovery Park; Purdue University; West Lafayette; USA; Jiang, Yuan [The Center for Direct Catalytic Conversion of Biomass to Biofuels (C3Bio); Discovery Park; Purdue University; West Lafayette; USA; Xiao, Weihua [Laboratory of Renewable Resources Engineering and Department of Agricultural and Biological Engineering; Purdue University; West Lafayette; USA; College of Engineering; Kenttämaa, Hilkka I. [The Center for Direct Catalytic Conversion of Biomass to Biofuels (C3Bio); Discovery Park; Purdue University; West Lafayette; USA; Abu-Omar, Mahdi M. [The Center for Direct Catalytic Conversion of Biomass to Biofuels (C3Bio); Discovery Park; Purdue University; West Lafayette; USA; Mosier, Nathan S. [Laboratory of Renewable Resources Engineering and Department of Agricultural and Biological Engineering; Purdue University; West Lafayette; USA; The Center for Direct Catalytic Conversion of Biomass to Biofuels (C3Bio)

    2016-01-01

    Maleic acid (MA) and AlCl3self-assemble into catalytic complexes (Al–(MA)2–(OH)2(aq)) with improved selectivity for converting glucose to HMF, and levulinic acid.

  2. Electrochemical studies on the reduction of uranyl ions in nitric acid-hydrazine media at platinum electrode

    International Nuclear Information System (INIS)

    Mishra, Satyabrata; Sini, K.; Mallika, C.; Kamachi Mudali, U.; Jagadeeswara Rao, Ch.

    2015-01-01

    Production of uranous nitrate with good conversion efficiency is one of the major steps in the aqueous reprocessing of spent fuels of nuclear reactors, as U(IV) is used for the separation of Pu from U by the selective reduction of Pu(IV) into practically non-extractable Pu(III) in aqueous streams. Electro-reduction of uranyl ions has the advantage of not introducing corrosive chemicals into the process stream. High current efficiency with maximum conversion of U(VI) to U(IV) can be achieved in continuous as well as batch mode electro-reduction, if the process is voltage-controlled rather than current controlled. As potentiostatic studies reveal the mechanism of reduction of uranyl ions in potential controlled electrolysis, the reduction behavior of uranyl ions (UO 2 2+ ) in nitric acid and nitric acid-hydrazine media were investigated by Cyclic Voltammetric (CV) and Chronopotentiometric (CP) techniques using platinum working electrode at 298 K. Heterogeneous electron transfer rate constant (ks) for uranyl reduction was estimated at a very low concentration of nitric acid (0.05 M) using Klinger and Kochi equation. Values of the diffusion coefficients were determined as a function of acidity with and without hydrazine. Reduction of uranyl ions was found to be under kinetic as well as diffusion control when the concentration of nitric acid was 0.05 M and in the absence of hydrazine. However, as the acidity of the supporting electrolyte increased, the reduction was purely under kinetic control. (author)

  3. Fixed bed sorption of phosphorus from wastewater using iron oxide-based media derived from acid mine drainage

    Science.gov (United States)

    Sibrell, Philip L.; Tucker, T.W.

    2012-01-01

    Phosphorus (P) releases to the environment have been implicated in the eutrophication of important water bodies worldwide. Current technology for the removal of P from wastewaters consists of treatment with aluminum (Al) or iron (Fe) salts, but is expensive. The neutralization of acid mine drainage (AMD) generates sludge rich in Fe and Al oxides that has hitherto been considered a waste product, but these sludges could serve as an economical adsorption media for the removal of P from wastewaters. Therefore, we have evaluated an AMD-derived media as a sorbent for P in fixed bed sorption systems. The homogenous surface diffusion model (HSDM) was used to analyze fixed bed test data and to determine the value of related sorption parameters. The surface diffusion modulus Ed was found to be a useful predictor of sorption kinetics. Values of Ed treatment costs while at the same time ameliorating the impacts of P contamination.

  4. Nitric acid adduct formation during crystallization of barium and strontium nitrates and their co-precipitation from nitric acid media

    International Nuclear Information System (INIS)

    Mishina, N.E.; Zilberman, B.Ya.; Lumpov, A.A.; Koltsova, T.I.; Puzikov, E.A.; Ryabkov, D.V.

    2015-01-01

    The molar solubilities of Ba, Sr and Pb nitrates in nitric acid as a function of total nitrate concentration is presented and described by the mass action law, indicating on formation of the adducts with nitric acid. Precipitates of Ba(NO 3 ) 2 and Sr(NO 3 ) 2 crystallized from nitric acid were studied by ISP OES and IR spectroscopy. The data obtained confirmed formation of metastable adducts with nitric acid. IR and X-ray diffraction studies of the mixed salt systems indicated conversion of the mixed salts into (Ba,Sr)(NO 3 ) 2 solid solution of discrete structure in range of total nitrate ion concentration ∼6 mol/L. (author)

  5. Selective liquid-liquid extraction of antimony(III from hydrochloric acid media by N-n-octylaniline in xylene

    Directory of Open Access Journals (Sweden)

    M. A. ANUSE

    2004-04-01

    Full Text Available N-n-Octylaniline in xylene was used for the extraction separation of antimony(III from hydrochloric acid media. Antimony(III was extracted quantitatively with 10 mL 4 % N-n-octylaniline in xylene. It was stripped from the organic phase with 0.5 M ammonia and estimated photometrically by the iodide method. The effect of metal ion, acid, reagent concentration and various foreign ions was investigated. The method affords binary and ternary separation of antimony(III from tellurium(IV, selenium(IV, lead(II, bismuth(III, tin(IV, germanium(IV, copper(II, gold(III, iron(III and zinc(II. The method is applicable for the analysis of synthetic mixtures, alloys and semiconductor thin films. It is fast, accurate and precise.

  6. Synthesis and corrosion inhibition application of NATN on mild steel surface in acidic media complemented with DFT studies

    Science.gov (United States)

    Al-Baghdadi, Shaimaa B.; Hashim, Fanar G.; Salam, Ahmed Q.; Abed, Talib K.; Gaaz, Tayser Sumer; Al-Amiery, Ahmed A.; Kadhum, Abdul Amir H.; Reda, Khalid S.; Ahmed, Wahab K.

    2018-03-01

    The corrosion inhibition effectiveness of thiosemicarbazide compound, namely 3-nitro-5-(2-amino-1,3,4-thiadiazolyl)nitrobenzene (NATN), on mild steel in 1 M hydrochloric acid media has been investigated by weight loss technique. The results exhibit that the corrosion ratio of mild steel was reduced regarding to adding NATN. The corrosion inhibition rate for the NATN was 92.3% at the highest investigated NATN concentration. From the weight loss results it could be concluded that NATN with sulfur, nitrogen and oxygen atoms has clarified best corrosion inhibition achievement comparing to 3,5-dinitrobenzoic acid. Regarding to theoretical studies, DFT was employee to figured geometrical structure and electronic characteristics on NATN. The investigation have been extensive to the HOMO and LUMO analysis to evaluate the energy gap, Ionization potential, Electron Affinity, Global Hardness, Chemical Potential, Electrophilicity, Electronegativity and Polarizability.

  7. Corrosion Inhibition of Aluminium in Acid Media By Citrullus Colocynthis Extract

    OpenAIRE

    Chauhan, Rajkiran; Garg, Urvija; Tak, R. K.

    2011-01-01

    Inhibition of corrosion of aluminium in acid solution by methanol extract of Citrullus colocynthis plant has been studied using mass loss and thermometric measurements. It has been found that the plant extract act as a good corrosion inhibitor for aluminium in all concentrations of sulphuric and hydrochloric acid solution. The inhibition action depends on the concentration of acid and inhibitor. Results for mass loss and thermometric measurement indicate that inhibition efficiency increase wi...

  8. The impact of reduced gastric acid secretion on dissolution of salts of weak bases in the fasted upper gastrointestinal lumen: Data in biorelevant media and in human aspirates.

    Science.gov (United States)

    Litou, Chara; Vertzoni, Maria; Xu, Wei; Kesisoglou, Filippos; Reppas, Christos

    2017-06-01

    To propose media for simulating the intragastric environment under reduced gastric acid secretion in the fasted state at three levels of simulation of the gastric environment and evaluate their usefulness in evaluating the intragastric dissolution of salts of weak bases. To evaluate the importance of bicarbonate buffer in biorelevant in vitro dissolution testing when using Level II biorelevant media simulating the environment in the fasted upper small intestine, regardless of gastric acid secretions. Media for simulating the hypochlorhydric and achlorhydric conditions in stomach were proposed using phosphates, maleates and bicarbonates buffers. The impact of bicarbonates in Level II biorelevant media simulating the environment in upper small intestine was evaluated so that pH and bulk buffer capacity were maintained. Dissolution data were collected using two model compounds, pioglitazone hydrochloride and semifumarate cocrystal of Compound B, and the mini-paddle dissolution apparatus in biorelevant media and in human aspirates. Simulated gastric fluids proposed in this study were in line with pH, buffer capacity, pepsin content, total bile salt/lecithin content and osmolality of the fasted stomach under partial and under complete inhibition of gastric acid secretion. Fluids simulating the conditions under partial inhibition of acid secretion were useful in simulating concentrations of both model compounds in gastric aspirates. Bicarbonates in Level III biorelevant gastric media and in Level II biorelevant media simulating the composition in the upper intestinal lumen did not improve simulation of concentrations in human aspirates. Level III biorelevant media for simulating the intragastric environment under hypochlorhydric conditions were proposed and their usefulness in the evaluation of concentrations of two model salts of weak bases in gastric aspirates was shown. Level II biorelevant media for simulating the environment in upper intestinal lumen led to

  9. Modelling extraction and separation of some alpha-transition elements from acidic media by synergic combinations of aromatic polyimines and micellar cationic exchangers

    International Nuclear Information System (INIS)

    Vitart, X.; Musikas, C.

    1988-01-01

    In this paper is emphasized, taking the extraction and separation by Dinonylnaphtalene sulfonic acid (HDMNS)of ruthenium-rhodium from a nitric acid media and nickel-cobalt from a sulfuric acid media as examples, the quantified chemical equilibria involved in order to elucidate the extraction mechanism. Reactions in aqueous media were investigated within three aspects: kinetics of formation, stability of metal complexes, ionic associations between complexes and mineral anions present in acidic media. This last point explains partly the selectivity of the system. The behaviour of HDNNS within extraction conditions, was studied leading to the structure of the micelle and to the quantification of equilibria involved (critical micelle concentration, polymerisation constant, etc...). Ligand extraction was studied previously to metal complexes extraction since the general mechanism of the system proceeds as a competitive extraction of cationic species in aqueous media (protonated forms of the free ligand, cationic metal complexes). The modelling of independent extraction of metals was used to predict numerically the behaviour of a multicomponent system where few metals are initially in aqueous media. These simulations are in accordance with experimental results

  10. O2 electrocatalysis in acid media on iron naphthalocyanine impregnations. Effect of nitric acid treatment on different carbon black supports

    NARCIS (Netherlands)

    Coowar, F.; Contamin, O.; Savy, M.; Scarbeck, G.; van den Ham, D.; Riga, J.; Verbist, J.J.

    1991-01-01

    O2 electrocatalysis on (2,3)FeNPc impregnations on different carbon blacks was investigated in H2SO4 medium. The effect of nitric acid treatment on the carbon black support is to enhance both the activity and stability of the catalyst. Moreover, as seen by XPS, the dissolution of iron is impeded by

  11. Kinetics and mechanism of the oxidation of uranium (IV) by hypochlorous acid in aqueous acidic perchlorate media

    International Nuclear Information System (INIS)

    Silverman, R.A.; Gordon, G.

    1976-01-01

    The oxidation of uranium(IV) by hypochlorous acid has been studied in aqueous sodium perchlorate--perchloric acid solutions. The reaction U 4 + + 2HOCl = UO 2 2 + + Cl 2 (aq) + 2H + proceeds appropriate to the rate law --d[U(IV)]/dt = k 0 . [U 4+ ][HOCl][H + ] -1 . At 25 0 and 3 M ionic strength, k 0 is 1.08 +- 0.07 sec -1 . Over the 1--25 0 temperature range, ΔH 2+ is 18.4 +- 0.1 kcal mole -1 , and ΔS 2+ is 3.1 +- 0.4 eu. The inverse hydrogen ion dependence of the rate law is explained by a rapid preequilibrium, in which a proton is lost from one of the reactants. A uranyl-like activated complex, [H 2 UO 2 Cl 3+ ] 2+ , is suggested, with one proton likely to be residing on each oxygen atom. Evidence is presented that the mechanism involves a two-electron transfer, with the intermediate chloride ion rapidly reacting with hypochlorous acid to form chlorine. The uranium(IV)-hypochlorous acid reaction plays an important role in the oxidation of uranium(IV) by aqueous chlorine solutions. The magnitude of this role was seriously underestimated by previous investigators

  12. Influence of culture media, pH and temperature on growth and bacteriocin production of bacteriocinogenic lactic acid bacteria.

    Science.gov (United States)

    Yang, En; Fan, Lihua; Yan, Jinping; Jiang, Yueming; Doucette, Craig; Fillmore, Sherry; Walker, Bradley

    2018-01-24

    There has been continued interest in bacteriocins research from an applied perspective as bacteriocins have potential to be used as natural preservative. Four bacteriocinogenic lactic acid bacteria (LAB) strains of Lactobacillus curvatus (Arla-10), Enterococcus faecium (JFR-1), Lactobacillus paracasei subsp. paracasei (JFR-5) and Streptococcus thermophilus (TSB-8) were previously isolated and identified in our lab. The objective of this study was to determine the optimal growth conditions for both LAB growth and bacteriocins production. In this study, various growth conditions including culture media (MRS and BHI), initial pH of culture media (4.5, 5.5, 6.2, 7.4 and 8.5), and incubation temperatures (20, 37 and 44 °C) were investigated for LAB growth measured as optical density (OD), bacteriocin activity determined as arbitrary unit and viability of LAB expressed as log CFU ml -1 . Growth curves of the bacteriocinogenic LAB were generated using a Bioscreen C. Our results indicated that Arla-10, JFR-1, and JFR-5 strains grew well on both MRS and BHI media at growth temperature tested whereas TSB-8 strain, unable to grow at 20 °C. LAB growth was significantly affected by the initial pH of culture media (p < 0.001) and the optimal pH was found ranging from 6.2 to 8.5. Bacteriocin activity was significantly different in MRS versus BHI (p < 0.001), and the optimal condition for LAB to produce bacteriocins was determined in MRS broth, pH 6.2 at 37 °C. This study provides useful information on potential application of bacteriocinogenic LAB in food fermentation processes.

  13. Fixed bed sorption of phosphorus from wastewater using iron oxide-based media derived from acid mine drainage

    Science.gov (United States)

    Sibrell, Philip L.; Tucker, T.W.

    2012-01-01

    Phosphorus (P) releases to the environment have been implicated in the eutrophication of important water bodies worldwide. Current technology for the removal of P from wastewaters consists of treatment with aluminum (Al) or iron (Fe) salts, but is expensive. The neutralization of acid mine drainage (AMD) generates sludge rich in Fe and Al oxides that has hitherto been considered a waste product, but these sludges could serve as an economical adsorption media for the removal of P from wastewaters. Therefore, we have evaluated an AMD-derived media as a sorbent for P in fixed bed sorption systems. The homogenous surface diffusion model (HSDM) was used to analyze fixed bed test data and to determine the value of related sorption parameters. The surface diffusion modulus Ed was found to be a useful predictor of sorption kinetics. Values of Ed < 0.2 were associated with early breakthrough of P, while more desirable S-shaped breakthrough curves resulted when 0.2 < Ed < 0.5. Computer simulations of the fixed bed process with the HSDM confirmed that if Ed was known, the shape of the breakthrough curve could be calculated. The surface diffusion coefficient D s was a critical factor in the calculation of Ed and could be estimated based on the sorption test conditions such as media characteristics, and influent flow rate and concentration. Optimal test results were obtained with a relatively small media particle size (average particle radius 0.028 cm) and resulted in 96 % removal of P from the influent over 46 days of continuous operation. These results indicate that fixed bed sorption of P would be a feasible option for the utilization of AMD residues, thus helping to decrease AMD treatment costs while at the same time ameliorating the impacts of P contamination.

  14. Influence of the acidity level change in aprotic media on the voltammetric behavior of nitrogabacinamamides

    International Nuclear Information System (INIS)

    Bautista-Martinez, J.A.; Gonzalez, I.; Aguilar-Martinez, M.

    2004-01-01

    This work presents a comparative voltammetric study of o-, m- and p-nitrogabacinamamides (N-[3(X-nitrophenyl)-(2E)-propenyl]-4-aminobutanoic acids), NG, in acetonitrile. These compounds, a HDR-NO 2 nitro compounds type, display three reduction waves, two of them are waves similar to those appearing in the reduction of the nitro compounds lacking a proton donor group and one new wave at less negative potentials, associated with the nitro-to-hydroxylamine reduction through a self-protonation reaction. Experiments were carried out in the presence of different chemical species giving an acidity level control by homogeneous buffer systems. The presence of tetraethylammonium phenolate achieves complete inhibition of self-protonation reactions, thus recovering the behavior established by ( - DR-NO 2 / - DR-NO 2 · - ) system. When the conjugated acid of the above mentioned base is added to the acetonitrile solution, where the acidity level was controlled by the phenol/phenolate system (acidity level buffer), only the second electroreduction wave ( - DR-NO 2 · - /HDR-NHOH) shows to be affected by the presence of phenol in the electrolytic medium and displaces towards less negative potential values. On the other hand, in the benzoic acid (HBz)/benzoate (Bz - ) medium, the electrochemical behavior of these nitro compounds changes completely passing from ( - DR-NO 2 / - DR-NO 2 · - ) system to (HDR-NO 2 + 4HBz/HDR-NHOH + 4Bz - ) type system, in which both the stoichiometry of the electroreduction process and the energetic requirement for its realization are changed. The comparison of the different voltammetric behavior in the presence of the different acidic and basic additives allowed constructing an acidity level scale where the different acid base couples of the intermediaries of the NG electroreduction were placed. This kind of scale allows choosing the chemical conditions necessaries to drive the pathway of the electrochemical transformation of nitro compounds

  15. Citric acid fermentation by gamma ray induced mutants of Aspergillus niger in different carbohydrate media

    Energy Technology Data Exchange (ETDEWEB)

    Anjuman Ara Begum; Naiyyum Choudhury; Mohammad Serajul Islam (Institute of Food and Radiation Biology, Dacca (Bangladesh))

    1990-01-01

    A natural isolate of Aspergillus niger, CA16, and two of its second step mutants, 136/40 and 277/30, grown on different sugar substrates gave maximum citric acid yields of 34, 70, and 126 mg/ml respectively in sucrose medium. Combination of two sugars in the medium at 50% of each improved the yields of citric acid for the sucrose: glucose, glucose: sorbitol, glucose: xylose, and xylose: sorbitol combinations with the mutant strains. Inclusion of galactose in combinations decreased the citric acid yield. (author).

  16. Citric acid fermentation by gamma ray induced mutants of Aspergillus niger in different carbohydrate media

    International Nuclear Information System (INIS)

    Anjuman Ara Begum; Naiyyum Choudhury; Mohammad Serajul Islam

    1990-01-01

    A natural isolate of Aspergillus niger, CA16, and two of its second step mutants, 136/40 and 277/30, grown on different sugar substrates gave maximum citric acid yields of 34, 70, and 126 mg/ml respectively in sucrose medium. Combination of two sugars in the medium at 50% of each improved the yields of citric acid for the sucrose: glucose, glucose: sorbitol, glucose: xylose, and xylose: sorbitol combinations with the mutant strains. Inclusion of galactose in combinations decreased the citric acid yield. (author)

  17. Effect of different media on production of lactic acid from whey by ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-01-05

    Jan 5, 2009 ... protein and 0.06% fat constituting an inexpensive and nutritionally rich raw material, high production rate and high yield for lactic acid fermentation. ... not a milk component, but a fermentation metabolite generated by certain ...

  18. Solvent extraction of hafnium(IV) by dinonylnaphthalene sulfonic acid from mixed aqueous-organic media

    International Nuclear Information System (INIS)

    Hala, J.; Piperkovova, H.

    1979-01-01

    The extraction of hafnium(IV) by heptane and toluene solutions of dinonylnaphthalene sulfonic acid (HD) from mixed aqueous-organic solutions has been studied. Alcohols, ketones, carboxylic acids, cyclic ethers, dimethylsulfoxide and dimethylformamide were used as the organic component of the mixed phase. Methanol, ethanol, formic acid and dioxane increased the extractability of Hf(IV) whereas other solvents showed only an antagonistic effect. The results were discussed from the point of view of the changes in micellar structure of HD, and compared with the uptake of Hf(IV) by resinous cation exchangers. The solubilization by HD of alcohols, carboxylic acids and dimethylsulfoxide was demonstrated by using the corresponding 14 C and 35 S labelled compounds. (author)

  19. Separation and preconcentration of actinides from acidic media by extraction chromatography

    International Nuclear Information System (INIS)

    Horwitz, E. Philip; Chiarizia, Renato; Dietz, Mark L.; Diamond, Herbert; Nelson, Donald M.

    1993-01-01

    A systematic examination of the effect of nitric and hydrochloric acid concentrations and of macro levels of selected elements on the sorption of actinide ions by a novel extraction chromatographic resin comprised of a solution of octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide in tri-n-butyl phosphate supported on an inert polymeric substrate is described. Actinide sorption is demonstrated to be most efficient at high (>1 M) nitric acid concentrations, although tetra- and hexavalent actinides are strongly retained even from dilute (e.g., 0.05 M) nitric acid solutions. Macro concentrations of several common anions (e.g., PO 4 3- and SO 4 2- ) or complexing agents (e.g., oxalic acid) are shown not to adversely affect the sorption of trivalent actinides, while reducing the sorption of tetravalents. Such effects, together with oxidation state adjustments, are shown to provide a basis for the sequential elution of individual actinides and for actinide isolation from environmental and biological matrices

  20. Transport and retention of 14C-perfluorooctanoic acid (PFOA) in saturated limestone and sand porous media: Effects of input concentration, ionic strength and cation type

    Science.gov (United States)

    Xueyan, L.; Gao, B.; Sun, Y.; Wu, J.

    2017-12-01

    Perfluorooctanoic acid (PFOA) has been used in a wide variety of industrial and consumer product applications. PFOA has been detected around the world at ng/L to μg/L levels in groundwater, and at ng/g levels in soil.The physicochemical properties of porous media were proven to play pivotal roles in determining the transport behavior of various pollutants. It is anticipated that physicochemical properties of porous media will strongly influence the transport behavior of PFOA. In addition, previous investigations have revealed that input concentration significantly influence the transport behavior of nanoparticles and antibiotics. Thus, this study was designed experimentally and fundamentally to gain insight into transport and retention of PFOA in various porous medias at different input concentrations, solution IS and cation type. Unlike in quartz sand porous media, the BTCs in limestone porous media exhibited increasing retention rate and high degree of tailing in limestone porous media. Results showed that higher relative retention occurred in limestone porous media than in quartz sand porous media under the same solution chemistry. This result was attributed to the less negative zeta-potentials, rougher surface and larger specific surface area, and the presence of hydroxyl groups and organic matters of limestone grains. Higher ionic strength and Ca2+ had little impact on the mobility of PFOA in quartz sand porous media, but significantly enhanced the retention of PFOA in limestone porous media. The difference is likely due to the compression of the electrical double layer, and the surface-charge neutralization and cation-bridging effect of Ca2+. Higher input concentration resulted in lower relative PFOA retention in limestone porous media, but the influence were insignificant in quartz sand porous media. This effect is likely because attachment sites in limestone responced to the variety of input concentration differently than quartz.

  1. Formation of complex precursors of amino acids by irradiation of simulated interstellar media with heavy ions

    Science.gov (United States)

    Kobayashi, K.; Suzuki, N.; Taniuchi, T.; Kaneko, T.; Yoshida, S.

    A wide variety of organic compounds have been detected in such extraterrestrial bodies as meteorites and comets Amino acids were identified in the extracts from Murchison meteorite and other carbonaceous chondrites It is hypothesized that these compounds are originally formed in ice mantles of interstellar dusts ISDs in molecular clouds by cosmic rays and ultraviolet light UV Formation of amino acid precursors by high energy protons or UV irradiation of simulated ISDs was reported by several groups The amino acid precursors were however not well-characterized We irradiated a frozen mixture of methanol ammonia and water with heavy ions to study possible organic compounds abiotically formed in molecular clouds by cosmic rays A mixture of methanol ammonia and water was irradiated with carbon beams 290 MeV u from a heavy ion accelerator HIMAC of National Institute of Radiological Sciences Japan Irradiation was performed either at room temperature liquid phase or at 77 K solid phase The products were characterized by gel filtration chromatography GFC FT-IR pyrolysis PY -GC MS etc Amino acids were analyzed by HPLC and GC MS after acid hydrolysis or the products Amino acids such as glycine and alanine were identified in the products in both the cases of liquid phase and solid phase irradiation Energy yields G-values of glycine were 0 014 liquid phase and 0 007 solid phase respectively Average molecular weights of the products were estimated as to 2300 in both the case Aromatic hydrocarbons N-containing heterocyclic

  2. Effective depolymerization of concentrated acid hydrolysis lignin using a carbon-supported ruthenium catalyst in ethanol/formic acid media.

    Science.gov (United States)

    Kristianto, Ivan; Limarta, Susan Olivia; Lee, Hyunjoo; Ha, Jeong-Myeong; Suh, Dong Jin; Jae, Jungho

    2017-06-01

    Lignin isolated by two-step concentrated acid hydrolysis of empty fruit bunch (EFB) was effectively depolymerized into a high-quality bio-oil using formic acid (FA) as an in-situ hydrogen source and Ru/C as a catalyst in supercritical ethanol. A bio-oil yield of 66.3wt% with an average molecular weight of 822g/mol and an aromatic monomer content of 6.1wt% was achieved at 350°C and a FA-to-lignin mass ratio of 3 after a reaction time of 60min. The combination of Ru/C and FA also resulted in a significant reduction in the oxygen content of the bio-oil by ∼60% and a corresponding increase in the higher heating value (HHV) to 32.7MJ/kg due to the enhanced hydrodeoxygenation activity. An examination of the FA decomposition characteristics revealed that Ru/C provides a greater increase in the rate of hydrogen production from FA, explaining the efficient depolymerization of lignin in a combined system. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Metal-Catalyzed Intra- and Intermolecular Addition of Carboxylic Acids to Alkynes in Aqueous Media: A Review

    Directory of Open Access Journals (Sweden)

    Javier Francos

    2017-11-01

    Full Text Available The metal-catalyzed addition of carboxylic acids to alkynes is a very effective tool for the synthesis of carboxylate-functionalized olefinic compounds in an atom-economical manner. Thus, a large variety of synthetically useful lactones and enol-esters can be accessed through the intra- or intermolecular versions of this process. In order to reduce the environmental impact of these reactions, considerable efforts have been devoted in recent years to the development of catalytic systems able to operate in aqueous media, which represent a real challenge taking into account the tendency of alkynes to undergo hydration in the presence of transition metals. Despite this, different Pd, Pt, Au, Cu and Ru catalysts capable of promoting the intra- and intermolecular addition of carboxylic acids to alkynes in a selective manner in aqueous environments have appeared in the literature. In this review article, an overview of this chemistry is provided. The synthesis of β-oxo esters by catalytic addition of carboxylic acids to terminal propargylic alcohols in water is also discussed.

  4. Solvent extraction of titanium (IV) from sulphuric acid media by cyanex 921 and tri-butylphosphate

    International Nuclear Information System (INIS)

    Nayl, A.A.; Aly, H.F.

    2009-01-01

    titanium and its compounds found different useful applications in the nuclear and radioactive waste treatment fields. extraction behavior of titanium (IV) from sulfuric acid by commercial tri-octylphosphine oxide (CYANEX 921) and tributylphosphate (TBP)has been investigated. effects of contact time, sulfuric acid concentration in the aqueous phase, the extractants concentration in the organic phase, and the temperature on the extraction of titanium by the two systems were studied. it is found that extraction equilibrium of titanium is reached after 10-15 min and 4 min for CYANEX 921 and TBP, respectively . the extraction of Ti(IV) by 0.15 M CYANEX 921 in kerosene increases with the increase in sulfuric acid concentration to reach a maximum extraction of 91% at 7.0 m acid concentration. for the TBP system, the maximum extraction of titanium was 79% using 1.0 M TBP in kerosene from 4.0 m H 2 SO 4 solution . the effect of temperature was also evaluated. Na 2 CO 3 was used as a good stripping agent compared with other reagents. the interaction of Ti(IV) in sulfate medium and different sulfate species in sulfuric acid are reviewed. within the literature survey together with analysis of the extraction results , it can be concluded that titanium extracted by CYANEX 921 as Ti O (HSO 4 ) 2 .2 CYANEX 921 whereby in case of TBP, the extracted species is TiOSO 4 .2 TBP

  5. Direct Capture of Organic Acids From Fermentation Media Using Ionic Liquids

    Energy Technology Data Exchange (ETDEWEB)

    Klasson, K.T.

    2004-11-03

    Several ionic liquids have been investigated for the extraction of organic acids from fermentation broth. Partitioning of representative organic acids (lactic, acetic, and succinic) between aqueous solution and nine hydrophobic ionic liquids was measured. The extraction efficiencies were strongly dependent on pH of the aqueous phase. Distribution coefficient was very good (approximately 60) at low succinic acid concentrations for one of the ionic liquids (trihexyltetradecylphosphonium methanesulfonate) at neutral pH. However, this ionic liquid had to be diluted with nonanol due to its high viscosity in order to be useful. A diluent (trioctylamine) was also added to this mixture. The results suggest that an extraction system based on ionic liquids may be feasible for succinic acid recovery from fermentation broth and that two ideal extraction stages are needed to reduce the concentration from 33 g/L to 1 g/L of succinic acid. Further studies are needed to evaluate other issues related to practical applications, including ionic liquid loss in the process, toxicity effects of ionic liquids during simultaneous fermentation and extractions.

  6. Interactions of short chain phenylalkanoic acids within ionic surfactant micelles in aqueous media

    Directory of Open Access Journals (Sweden)

    Naeem Kashif

    2012-01-01

    Full Text Available % SDS KR nema Solubilization and interactions of phenylalkanoic acids induced by cationic surfactant, cetyltrimethylammonium bromide (CTAB and an anionic surfactant, sodium dodecyl sulfate (SDS was investigated spectrophotometrically at 25.0°C. The UV spectra of the additives (acids were measured with and without surfactant above and below critical micelle concentration (cmc of the surfactant. The presence of alkyl chain in phenylalkanoic acids is responsible for hydrophobic interaction resulting in shift of the spectra towards longer wavelength (red shift. The value of partition coefficient (Kx between the bulk water and surfactant micelles and in turn standard free energy change of solubilization (ΔGpº were also estimated by measuring the differential absorbance (ΔA of the additives in micellar solutions.

  7. Corrosion Inhibition of Aluminium in Acid Media By Citrullus Colocynthis Extract

    Directory of Open Access Journals (Sweden)

    Rajkiran Chauhan

    2011-01-01

    Full Text Available Inhibition of corrosion of aluminium in acid solution by methanol extract of Citrullus colocynthis plant has been studied using mass loss and thermometric measurements. It has been found that the plant extract act as a good corrosion inhibitor for aluminium in all concentrations of sulphuric and hydrochloric acid solution. The inhibition action depends on the concentration of acid and inhibitor. Results for mass loss and thermometric measurement indicate that inhibition efficiency increase with increasing inhibitor concentration. The inhibition action of the plant extract is discussed in view of Langmuir adsorption isotherm. It has been observed that the adsorption of the extract on aluminium surface is a spontaneous process. The plant extract provides a good protection to aluminium against corrosion.

  8. Influence of media with different acidity on structure of FeNi nanotubes

    Directory of Open Access Journals (Sweden)

    Shumskaya Alena

    2018-01-01

    Full Text Available A detailed analysis of the structure features of FeNi nanotubes exposed at environment with different acidity is carried out. It is demonstrated that the exposure of the nanostructures in the environment with high acidity causes the structure deformation, leading to sharply increasing of the presents of oxide phases and partial amorphization of nanotubes walls that determined the rate of FeNi nanotubes destruction. It was established that the evolution of the crystal structure parameters concerned with appearance of oxide phases and with formation of disorder regions as a result of oxidation processes.

  9. Influence of media with different acidity on structure of FeNi nanotubes

    Science.gov (United States)

    Shumskaya, Alena; Kaniukov, Egor; Kutuzau, Maksim; Bundyukova, Victoria; Tulebayeva, Dinara; Kozlovskiy, Artem; Borgekov, Daryn; Kenzhina, Inesh; Zdorovets, Maxim

    2018-04-01

    A detailed analysis of the structure features of FeNi nanotubes exposed at environment with different acidity is carried out. It is demonstrated that the exposure of the nanostructures in the environment with high acidity causes the structure deformation, leading to sharply increasing of the presents of oxide phases and partial amorphization of nanotubes walls that determined the rate of FeNi nanotubes destruction. It was established that the evolution of the crystal structure parameters concerned with appearance of oxide phases and with formation of disorder regions as a result of oxidation processes.

  10. Baphia nitida Leaves Extract as a Green Corrosion Inhibitor for the Corrosion of Mild Steel in Acidic Media

    Directory of Open Access Journals (Sweden)

    V. O. Njoku

    2014-01-01

    Full Text Available The inhibiting effect of Baphia nitida (BN leaves extract on the corrosion of mild steel in 1 M H2SO4 and 2 M HCl was studied at different temperatures using gasometric and weight loss techniques. The results showed that the leaves extract is a good inhibitor for mild steel corrosion in both acid media and better performances were obtained in 2 M HCl solutions. Inhibition efficiency was found to increase with increasing inhibitor concentration and decreasing temperature. The addition of halides to the extract enhanced the inhibition efficiency due to synergistic effect which improved adsorption of cationic species present in the extract and was in the order KCl < KBr < KI suggesting possible role of radii of the halide ions. Thermodynamic parameters determined showed that the adsorption of BN on the metal surface is an exothermic and spontaneous process and that the adsorption was via a physisorption mechanism.

  11. Time-resolved fluorescence of cationic dyes covalently bound to poly(methacrylic acid) in rigid media

    Energy Technology Data Exchange (ETDEWEB)

    Paulo Moises de Oliveira, Hueder [Instituto de Quimica de Sao Carlos, Universidade de Sao Paulo, Sao Carlos, SP (Brazil); Gehlen, Marcelo Henrique [Instituto de Quimica de Sao Carlos, Universidade de Sao Paulo, Sao Carlos, SP (Brazil)]. E-mail: marcelog@iqsc.usp.br

    2006-12-15

    Atactic poly(methacrylic acid) labeled with acridine and Nile blue (NB) were studied by photophysical techniques in bulk solid state and in solution-cast films over different surfaces (glass, ITO, and polymethylmethacrylate). In the systems with both dyes, energy transfer from acridine to NB occurs with an efficiency depending on the type of substrate (solid or film). The films are more disordered fluorescent rigid media than the bulk chromophoric or bichromophoric polymers, and this effect is ascribed to inhomogeneous distribution of the dyes in the film. This effect enhances dye bimolecular interactions and increases the energy transfer rates between acridine donor and NB acceptor. Bimodal distributions of donor fluorescence lifetimes are observed.

  12. Use of fatty acid methyl ester profiles for discrimination of Bacillus cereus T-strain spores grown on different media.

    Science.gov (United States)

    Ehrhardt, Christopher J; Chu, Vivian; Brown, TeeCie; Simmons, Terrie L; Swan, Brandon K; Bannan, Jason; Robertson, James M

    2010-03-01

    The goal of this study was to determine if cellular fatty acid methyl ester (FAME) profiling could be used to distinguish among spore samples from a single species (Bacillus cereus T strain) that were prepared on 10 different medium formulations. To analyze profile differences and identify FAME biomarkers diagnostic for the chemical constituents in each sporulation medium, a variety of statistical techniques were used, including nonmetric multidimensional scaling (nMDS), analysis of similarities (ANOSIM), and discriminant function analysis (DFA). The results showed that one FAME biomarker, oleic acid (18:1 omega9c), was exclusively associated with spores grown on Columbia agar supplemented with sheep blood and was indicative of blood supplements that were present in the sporulation medium. For spores grown in other formulations, multivariate comparisons across several FAME biomarkers were required to discern profile differences. Clustering patterns in nMDS plots and R values from ANOSIM revealed that dissimilarities among FAME profiles were most pronounced when spores grown with disparate sources of complex additives or protein supplements were compared (R > 0.8), although other factors also contributed to FAME differences. DFA indicated that differentiation could be maximized with a targeted subset of FAME variables, and the relative contributions of branched FAME biomarkers to group dissimilarities changed when different media were compared. When taken together, these analyses indicate that B. cereus spore samples grown in different media can be resolved with FAME profiling and that this may be a useful technique for providing intelligence about the production methods of Bacillus organisms in a forensic investigation.

  13. Corrosion behaviour of 6063 aluminium alloy in acidic and in alkaline media

    Directory of Open Access Journals (Sweden)

    Prabhu Deepa

    2017-05-01

    Full Text Available The corrosion behaviour of 6063 aluminium alloy was investigated in different concentrations of phosphoric acid medium and sodium hydroxide medium at different temperatures. The study was done by electrochemical method, using Tafel polarization technique and electrochemical impedance spectroscopy (EIS technique. The surface morphology was investigated using scanning electron microscope (SEM with Energy-dispersive X-ray spectroscopy (EDX. The results showed that the 6063 aluminium alloy undergoes severe corrosion in sodium hydroxide medium than in phosphoric acid medium. The corrosion rate of 6063 aluminium alloy increased with an increase in the concentration of acid as well as with alkali. The corrosion rate was increased with an increase in temperature. The kinetic parameters and thermodynamic parameters were calculated using Arrhenius theory and transition state theory. Suitable mechanism was proposed for the corrosion of 6063 aluminium alloy in phosphoric acid medium and sodium hydroxide medium. The results obtained by Tafel polarization and electrochemical impedance spectroscopy (EIS techniques were in good agreement with each other.

  14. Corrosion behaviour of WC-VC-Co hardmetals in acidic media

    CSIR Research Space (South Africa)

    Konadu, DS

    2010-09-01

    Full Text Available The effect of increasing vanadium carbide (VC) content on the corrosion behaviour of tungsten carbide – 10 wt% cobalt hard metals was investigated in 1 M hydrochloric (HCl), and sulphuric (H2SO4) acids solutions. Increasing VC content makes the open...

  15. Spectrophotometric investigation of the Acidity constants of fluorescein in various water-organic solvent media

    Czech Academy of Sciences Publication Activity Database

    Niazi, A.; Yazdanipour, A.; Ghasemi, J.; Amini, A.; Bozorgzad, S.; Kubista, Mikael

    2008-01-01

    Roč. 195, č. 10 (2008), s. 1257-1268 ISSN 0098-6445 Institutional research plan: CEZ:AV0Z50520701 Keywords : Acid ionization constant * acidy * fluorecein Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 0.585, year: 2008

  16. Development of partitioning method. Adsorption of cesium with mordenite in acidic media

    Energy Technology Data Exchange (ETDEWEB)

    Donnet, L.; Morita, Yasuji; Yamagishi, Isao; Kubota, Masumitsu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-10-01

    Adsorption of cesium with mordenite from a acidic solution, typically from a 0.5 mol/L nitric acid solution, was studied to examine the possibility to design a new separation scheme for partitioning of high-level liquid waste. Batch adsorption experiments showed that three mordenites examined (natural mordenite and two synthetic mordenites Zeolon 900Na and 900H) have very close behavior with the parameters of adsorption kinetics, the saturation capacity by Langmuir equation, the distribution coefficient of Cs and adsorption of other elements. In the Cs adsorption with the natural mordenite at 0.5 mol/L nitric acid, distribution coefficient was 1150 ml/g and the saturation capacity was 0.64 mmol/g. In the adsorption of Cs on column using the natural mordenite, the flow rate of the Cs solution modified only the 5% breakthrough point and gave no influence on the total capacity of Cs. Column experiments with a mixed solution of Cs, Rb, Na, Ba, Sr, Cr, Ni, Ru, Rh and Pd showed that cesium was adsorbed very selectively. Only about 4% of rubidium in a molar ratio were retained in the column. The total quantity of Cs and Rb adsorbed was 0.51 mmol/g at 0.5 mol/L nitric acid. Elution of Cs (and Rb) with 4 mol/L nitric acid was performed against the column of the loaded natural mordenite. The adsorbed Cs and Rb were well eluted, and a good mass balance was obtained between the adsorbed quantity by breakthrough curves and the quantity found in the eluate. (author)

  17. Adsorption and inhibitive properties of Tryptophan on low alloy steel corrosion in acidic media

    Directory of Open Access Journals (Sweden)

    Hesham T.M. Abdel-Fatah

    2017-02-01

    Corrosion inhibition was studied using electrochemical methods (electrochemical impedance spectroscopy; EIS and the new technique electrochemical frequency modulation; EFM and weight loss measurements. The influence of inhibitor concentration, solution temperature, and immersion time on the corrosion resistance of low alloy steel (LAS has been investigated. Trp proved to be a very good inhibitor for low alloy steel acid corrosion. EFM measurements showed that Trp is a mixed type inhibitor. Trp behaved better in 0.6 M HCl than in 0.6 M HSO3NH2. Moreover, it was found that the inhibition efficiency increased with increasing inhibitor concentration, while a decrease was detected with the rise of temperature and immersion time. The associated activation energy (Ea has been determined. The values of Ea indicate that the type of adsorption of Trp on the steel surface in both acids belongs to physical adsorption. The adsorption process was tested using Temkin adsorption isotherm.

  18. Electrochemistry of carbonaceous materials; 2. Anodic electroactivity of coal slurries in 85% phosphoric acid media

    Energy Technology Data Exchange (ETDEWEB)

    Tomat, R.; Salmaso, R.; Zecchin, S. (CNR-Instituto di Polarografia ed Elettrochimica Preparative, Padova (Italy))

    1992-04-01

    Current-potential curves of suspended coal (Sulcis basin, Sardinia, Italy) in 85% H{sub 3}PO{sub 4} were taken on a platinum electrode at 100{degree}C. Anodic current in the potential range of 0-1.5 V versus saturated calomel electrode was due to some humic acid-type substances released by coal in the electrolyte. The leaching of organic matter increased with the lowering of the particle dimensions, and the related oxidation currents attained stable values even during slurry formation. Current-potential curves were still unchanged when coal was filtered off from the suspension. Previous washing of ground coal with diluted mineral acids, including H{sub 3}PO{sub 4}, did not dissolve any significant amount of the substances responsible for the electrochemical activity of the coal sample examined. 14 refs., 6 figs.

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

    Science.gov (United States)

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

    2018-02-01

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

  20. Morphology-dependent activity of Pt nanocatalysts for ethanol oxidation in acidic media: Nanowires versus nanoparticles

    International Nuclear Information System (INIS)

    Zhou Weiping; Li Meng; Koenigsmann, Christopher; Ma Chao; Wong, Stanislaus S.; Adzic, Radoslav R.

    2011-01-01

    Highlights: → We demonstrate the morphology effect of Pt catalysts in electrooxidation of ethanol and CO in an acidic solution. → Pt nanowires and nanoparticles were used as catalysts. → Pt nanowires display a higher catalytic activity by a factor of at least two relative to those nanoparticles for ethanol oxidation. → The rate for CO monolayer oxidation exhibits similar morphology-dependent behavior with a markedly enhanced rate on the Pt nanowires. - Abstract: The morphology of nanostructured Pt catalysts is known to affect significantly the kinetics of various reactions. Herein, we report on a pronounced morphology effect in the electrooxidation of ethanol and carbon monoxide (CO) on Pt nanowires and nanoparticles in an acidic solution. The high resolution transmission electron microscopy analysis showed the inherent morphology difference between these two nanostructured catalysts. Voltammetric and chronoamperometric studies of the ethanol electrooxidation revealed that these nanowires had a higher catalytic activity by a factor of two relative to these nanoparticles. The rate for CO monolayer oxidation exhibits similar morphology-dependent behavior with a markedly enhanced rate on the Pt nanowires. In situ infrared reflection-absorption spectroscopy measurements revealed a different trend for chemisorbed CO formation and CO 2 -to-acetic acid reaction product ratios on these two nanostructures. The morphology-induced change in catalytic activity and selectivity in ethanol electrocatalysis is discussed in detail.

  1. Review and assessment of technologies for the separation of cesium from acidic media

    Energy Technology Data Exchange (ETDEWEB)

    Orth, R.J.; Brooks, K.P.; Kurath, D.E.

    1994-09-01

    A preliminary literature survey has been conducted to identify and evaluate methods for the separation of cesium from acidic waste. The most promising solvent extraction, precipitation, and ion exchange methods, along with some of the attributes for each method, are listed. The main criteria used in evaluating the separation methods were as follows: (1) good potential for cesium separation must be demonstrated (i.e., cesium decontamination factors on the order of 50 to 100). (2) Good selectivity for cesium over bulk components must be demonstrated. (3) The method must show promise for evolving into a practical and fairly simple process. (4) The process should be safe to operate. (5) The method must be robust (i.e., capable of separating cesium from various acidic waste types). (6) Secondary waste generation must be minimized. (7) The method must show resistance to radiation damage. The most promising separation methods did not necessarily satisfy all of the above criteria, thus key areas requiring further development are suggested for each method. The report discusses in detail these and other areas requiring further development, as well as alternative solvent extraction, precipitation, ion exchange, and {open_quote}other{close_quote} technologies that, based on current information, show less promise for the separation of cesium from acidic wastes because of significant process limitations. When appropriate, the report recommends areas of future development.

  2. Morphology-dependent activity of Pt nanocatalysts for ethanol oxidation in acidic media: Nanowires versus nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Weiping, E-mail: wpzhou@bnl.gov [Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Li Meng [Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Koenigsmann, Christopher [Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794 (United States); Ma Chao [Condensed Matter Physics and Materials Sciences Department, Brookhaven National Laboratory, Building 480, Upton, NY 11973 (United States); Wong, Stanislaus S. [Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794 (United States); Condensed Matter Physics and Materials Sciences Department, Brookhaven National Laboratory, Building 480, Upton, NY 11973 (United States); Adzic, Radoslav R. [Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2011-11-30

    Highlights: > We demonstrate the morphology effect of Pt catalysts in electrooxidation of ethanol and CO in an acidic solution. > Pt nanowires and nanoparticles were used as catalysts. > Pt nanowires display a higher catalytic activity by a factor of at least two relative to those nanoparticles for ethanol oxidation. > The rate for CO monolayer oxidation exhibits similar morphology-dependent behavior with a markedly enhanced rate on the Pt nanowires. - Abstract: The morphology of nanostructured Pt catalysts is known to affect significantly the kinetics of various reactions. Herein, we report on a pronounced morphology effect in the electrooxidation of ethanol and carbon monoxide (CO) on Pt nanowires and nanoparticles in an acidic solution. The high resolution transmission electron microscopy analysis showed the inherent morphology difference between these two nanostructured catalysts. Voltammetric and chronoamperometric studies of the ethanol electrooxidation revealed that these nanowires had a higher catalytic activity by a factor of two relative to these nanoparticles. The rate for CO monolayer oxidation exhibits similar morphology-dependent behavior with a markedly enhanced rate on the Pt nanowires. In situ infrared reflection-absorption spectroscopy measurements revealed a different trend for chemisorbed CO formation and CO{sub 2}-to-acetic acid reaction product ratios on these two nanostructures. The morphology-induced change in catalytic activity and selectivity in ethanol electrocatalysis is discussed in detail.

  3. Thin layer spectroelectrochemical studies of pertechnetate reduction on the gold electrodes in acidic media

    International Nuclear Information System (INIS)

    Chotkowski, M.; Czerwiński, A.

    2014-01-01

    The electroreduction of pertechnetate ions has been examined in sulfuric acid solutions (0.5 M ÷ 4 M H 2 SO 4 ) using rotating disc electrodes (Au-RDE) and optically transparent thin layer spectroelectrochemical cells (Au/RVC-OTTLE). Soluble Tc(III,IV) species with absorption bands at 502 nm were found to be formed during the reduction of TcO 4 − . The hydrodynamic experiments (Au-RDE) have shown the influence of the acidity of the solution on the activation energy of the electroreduction of the pertechnetate ions to technetium(III,IV) species. The value of the activation energy calculated for limiting current was found to increase from 12.6 ± 1.1 kJ mol −1 for 4 M H 2 SO 4 to 20.1 ± 0.8 kJ mol −1 for 0.5 M H 2 SO 4 . Such an effect suggests an influence of the acid concentration on the structure of obtained products, which are soluble or insoluble Tc species. Thin layer spectroelectrochemical experiments allowed calculation of the redox standard potentials for Tc 2 O 2 3+ /TcO(OH) (aq) system which was found to be equal to 0.255 V vs. Ag,AgCl (KClsat.)

  4. Extraction and separation of U(VI and Th(IV from hydrobromic acid media using Cyanex-923 extractant

    Directory of Open Access Journals (Sweden)

    Ghag Snehal M.

    2010-01-01

    Full Text Available A systematic study of the solvent extraction of uranium(VI and thorium(IV from hydrobromic acid media was performed using the neutral phosphine oxide extractant Cyanex-923 in toluene. These metal ions were found to be quantitatively extracted with Cyanex-923 in toluene in the acidity range 5x10-5-1x10-4 M and 5x10-5-5x10-3 M, respectively, and they are stripped from the organic phase with 7.0 M HClO4 and 2.0- 4.0 M HCl, respectively. The effect of the equilibrium period, diluents, diverse ions and stripping agent on the extraction of U(VI and Th(IV was studied. The stoichiometry of the extracted species of these metal ions was determined based on the slope analysis method. The extraction reactions proceed by solvation and their probable extracted species found in the organic phase were UO2Br2•2Cyanex-923 and ThBr4•2Cyanex-923. Based on these results, a sequential procedure for their separation from each other was developed.

  5. Amino acids supply in culture media is not a limiting factor in the matrix synthesis of engineered cartilage tissue

    Science.gov (United States)

    Ng, K. W.; DeFrancis, J. G.; Kugler, L. E.; Kelly, T.-A. N.; Ho, M. M.; O’Conor, C. J.; Ateshian, G. A.; Hung, C. T.

    2013-01-01

    Summary Increased amino acid supplementation (0.5×, 1.0×, and 5.0× recommended concentrations or additional proline) was hypothesized to increase the collagen content in engineered cartilage. No significant differences were found between groups in matrix content or dynamic modulus. Control constructs possessed the highest compressive Young’s modulus on day 42. On day 42, compared to controls, decreased type II collagen was found with 0.5×, 1.0×, and 5.0× supplementation and significantly increased DNA content found in 1.0× and 5.0×. No effects were observed on these measures with added proline. These results lead us to reject our hypothesis and indicate that the low collagen synthesis in engineered cartilage is not due to a limited supply of amino acids in media but may require a further stimulatory signal. The results of this study also highlight the impact that culture environment can play on the development of engineered cartilage. PMID:17713744

  6. Transport and Retention of TiO2 Rutile Nanoparticles in Saturated Porous Media: Influence of Solution pH, Ionic Strength, and the Presence of Humic Acid

    Science.gov (United States)

    The influence of solution pH, ionic strength, and varying concentrations of the Suwannee River Humic Acid (SRHA) on the transport of titanium dioxide (TiO2, rutile) nanoparticle aggregates (nTiO2) in saturated porous media was investigated through systematically examining the tra...

  7. Separation and immobilization of Sr and Cs contained in acidic media by using inorganic ion-exchangers. Literature survey

    Energy Technology Data Exchange (ETDEWEB)

    Yamagishi, Isao [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-07-01

    The present study deals with the survey of inorganic ion-exchangers suitable for separation and immobilization of Sr and Cs contained in acidic high-level liquid waste. The stabilities of published waste forms and their preparation processes were evaluated from the standpoint of conversion of exchangers containing Sr and Cs into appropriate waste forms. The essential results are below. (1) For separation and immobilization of Cs, crystalline silicotitanate seems to be the most promising exchanger. Insoluble ferrocyanides and phosphates are not suitable for immobilization without additives. Mordenite is inexpensive and commercially available but it would dissolve in highly acidic media. (2) For selective separation of Sr, there is no promising exchanger up to now. It is necessary either to modify separation condition or to synthesize a novel exchanger. (3) Soluble salts, glasses and ceramics are proposed as a storage or disposal form of separated Sr and Cs. Ceramics sintered by hot-pressing are favorable waste forms of inorganic ion-exchangers but their leachabilities and thermal conductivities are largely influenced by qualities of products. Crystallinity of a sintered exchanger depends on its composition. Exchanges of low Cs contents are often converted into amorphous materials whose chemical stabilities depend on solubilities of components of exchangers. (4) A new exchanger to be synthesized is crystalline and selective toward Sr and Cs. One meq/g is enough for Sr and Cs capacities, which are restricted by thermal and transmutation effects. Composition of the exchanger should be selected from the point of a scenario of separation and disposal. The solubilities of SiO{sub 2}, TiO{sub 2}, ZrO{sub 2}, Nb{sub 2}O{sub 5} and Ta{sub 2}O{sub 5} are low in acidic media and those of Al{sub 2}O{sub 3}, TiO{sub 2} and ZrO{sub 2}, in disposal circumstances. (5) Future works are optimization of separation scheme including development of exchangers, simplification of

  8. Fermentation Conditions and Media Optimization for Isocitric Acid Production from Ethanol by Yarrowia lipolytica

    Directory of Open Access Journals (Sweden)

    Svetlana V. Kamzolova

    2018-01-01

    Full Text Available Isocitric acid exists in the form of four stereoisomers, of which only the threo-Ds-form (ICA is a natural active compound, an intermediate of Krebs cycle, and suitable for nutritional and pharmaceutical use. In this paper, we propose a method for ICA production from ethanol by yeast Yarrowia lipolytica. The effects of temperature, pH of the medium, and aeration on the growth of the producer Y. lipolytica VKM Y-2373 and synthesis of ICA were studied. An optimal fermentation regime, which ensures a good growth of the producer and directed synthesis of the target product, was determined. The producer is advised to carry out cultivation at 29°C and various pH of the medium and the oxygen concentration (pH 5 and pO2 20–25% (of saturation during the growth period and pH 6 and pO2 50–55% (of saturation during the acid formation on a nutrient medium containing an increased content of zinc (0.6 mg/L, iron (1.2 mg/L, and 30 mM itaconic acid (inhibitor of isocitrate lyase—the key enzyme of ICA metabolism should also be introduced into the nutrition medium. Such fermentation production mode provides 90.5 g/L ICA with process selectivity of 80%, mass yield (YICA of 0.77 g/g, and energy yield (ηICA of 0.278 g/g.

  9. THERMODYNAMICS OF CESIUM EXTRACTION FROM ACIDIC MEDIA BY HCCD and PEG

    International Nuclear Information System (INIS)

    Herbst, R. Scott; Peterman, Dean R.; Zalupski, Peter R.; Nash, Ken L.; Tillotson, Richard D.; Delmau, Laetitia H.

    2010-01-01

    This is a companion study to previous publications which expands the understanding of cesium extraction from nitrate media using chlorinated cobalt dicarbollide (HCCD) dissolved in the polar phenyl trifluoromethyl sulfone (FS-13) diluent. First, it is verified that the system is based solely on cation exchange between H+ and Cs+ and that NO3- does not intervene, i.e., that the apparent nitrate dependency is merely an artifact of solution non-idealities. Next, the enthalpy and entropy of the system were determined using appropriate corrections in the van't Hoff analysis and are in excellent agreement with independently published calorimetry results. Finally, the extraction of Cs by the system containing both HCCD and polyethylene glycol (PEG) in FS-13 was characterized by the determination the species produced in the organic and aqueous phases and it is further demonstrated that synergistic extraction of Cs by HCCD and PEG does not occur. Although there is a definite interaction between HCCD and PEG, and it is well established that this interaction is responsible for the extraction of Sr, this association is actually antagonist with respect to the extraction of Cs.

  10. Kinetics study on the reduction of trace plutonium (IV) by hydroxylamine in nitric acid media

    International Nuclear Information System (INIS)

    Fei Hongcheng; Luo Longjun

    1998-01-01

    Reaction kinetics of trace Pu(IV) (c(Pu(IV)≤10 -5 mol/L) with hydroxylamine in nitric acid solution is investigated. The effects of concentrations of Pu(IV), Pu(III), NO 3 - , H + and hydroxylamine on the reduction rate of trace Pu(IV) are examined. The rate law of reaction of trace Pu(IV) with hydroxylamine is obtained. The reduction rate of Pu(IV) increases obviously with increasing temperature and the apparent activation energy with k' 0 is equal to 147 kJ/mol. The reaction mechanism of trace Pu(IV) with hydroxylamine is discussed

  11. Influence of poly(aminoquinone) on corrosion inhibition of iron in acid media

    Science.gov (United States)

    Jeyaprabha, C.; Sathiyanarayanan, S.; Phani, K. L. N.; Venkatachari, G.

    2005-11-01

    The inhibitor performance of chemically synthesized water soluble poly(aminoquinone) (PAQ) on iron corrosion in 0.5 M sulphuric acid was studied in relation to inhibitor concentration using potentiodynamic polarization and electrochemical impedance spectroscopy measurements. On comparing the inhibition performance of PAQ with that of the monomer o-phenylenediamine (OPD), the OPD gave an efficiency of 80% for 1000 ppm while it was 90% for 100 ppm of PAQ. PAQ was found to be a mixed inhibitor. Besides, PAQ was able to improve the passivation tendency of iron in 0.5 M H 2SO 4 markedly.

  12. The implications of particle energy and acidic media on gross alpha and gross beta determination using liquid scintillation

    Energy Technology Data Exchange (ETDEWEB)

    Zapata-Garcia, D. [Laboratori de Radiologia Ambiental (LRA), Departament de Quimica Analitica, Universitat de Barcelona, Marti i Franques, 1-11 Planta 3, E-08028 Barcelona (Spain); Llaurado, M., E-mail: montse.llaurado@ub.edu [Laboratori de Radiologia Ambiental (LRA), Departament de Quimica Analitica, Universitat de Barcelona, Marti i Franques, 1-11 Planta 3, E-08028 Barcelona (Spain); Rauret, G. [Laboratori de Radiologia Ambiental (LRA), Departament de Quimica Analitica, Universitat de Barcelona, Marti i Franques, 1-11 Planta 3, E-08028 Barcelona (Spain)

    2012-04-15

    The interaction of humans with radioactivity present in the environment from natural and artificial sources necessitates an evaluation of its risk on human health. Gross alpha and gross beta activities can provide a rapid evaluation of the radioactive content of a sample and can be simultaneously determined by using liquid scintillation counters. However, calibration of the liquid scintillation counter is required and is affected by many factors, such as particle energy and the acidity of the media. This study investigates what effect the particle energy used for calibration has on misclassification and how to account for this misclassification in routine measurements. The variability in measurement produced by the final pH, as well as any acids used in sample treatment, was also studied. These results showed that the most commonly used acid for these types of analyses, HNO{sub 3}, produced a high amount of misclassifications at very low pH. The results improved when HCl was used to adjust the sample to low pH. - Highlights: Black-Right-Pointing-Pointer We study the effect of alpha and beta energies on PSA optimisation. Black-Right-Pointing-Pointer The optimum PSA shifts to higher values as the alpha energy increases. Beta energies do not affect it. Black-Right-Pointing-Pointer We study the effect of pH on the simultaneous determination of gross alpha/beta activities. Black-Right-Pointing-Pointer HNO{sub 3} produces a high amount of misclassification at very low pH. Black-Right-Pointing-Pointer The results improve when HCl is used to adjust the sample to low pH.

  13. The implications of particle energy and acidic media on gross alpha and gross beta determination using liquid scintillation

    International Nuclear Information System (INIS)

    Zapata-García, D.; Llauradó, M.; Rauret, G.

    2012-01-01

    The interaction of humans with radioactivity present in the environment from natural and artificial sources necessitates an evaluation of its risk on human health. Gross alpha and gross beta activities can provide a rapid evaluation of the radioactive content of a sample and can be simultaneously determined by using liquid scintillation counters. However, calibration of the liquid scintillation counter is required and is affected by many factors, such as particle energy and the acidity of the media. This study investigates what effect the particle energy used for calibration has on misclassification and how to account for this misclassification in routine measurements. The variability in measurement produced by the final pH, as well as any acids used in sample treatment, was also studied. These results showed that the most commonly used acid for these types of analyses, HNO 3 , produced a high amount of misclassifications at very low pH. The results improved when HCl was used to adjust the sample to low pH. - Highlights: ► We study the effect of alpha and beta energies on PSA optimisation. ► The optimum PSA shifts to higher values as the alpha energy increases. Beta energies do not affect it. ► We study the effect of pH on the simultaneous determination of gross alpha/beta activities. ► HNO 3 produces a high amount of misclassification at very low pH. ► The results improve when HCl is used to adjust the sample to low pH.

  14. Study of reverse flotation of calcite from scheelite in acidic media

    Science.gov (United States)

    Deng, Rongdong; Huang, Yuqing; Hu, Yuan; Ku, Jiangang; Zuo, Weiran; Yin, Wanzhong

    2018-05-01

    A new coated-reactive reverse flotation method based on the generation of CO2 bubbles at a calcite surface in acidic solution was used to separate calcite from scheelite. The dissolution kinetics of coated and uncoated calcite were studied in sulfuric acid. The CO2 bubbles generated on the uncoated calcite particle surface are enough to float the particle. However, most of these bubbles left the surface quickly, preventing calcite from floating. Here, a mixture of polyvinyl alcohol polymer and sodium dodecyl sulfonate was used to coat the mineral particles and form a stable membrane, resulting in the formation of a stable foam layer on the calcite surface. After the calcite is coated, the generated bubbles could be successfully captured on the calcite surface, and calcite particles could float to the air-water interface and remain there for more than one hour. Flotation tests indicated that a high-quality tungsten concentrate with a grade of more than 75% and a recovery of more than 99% could be achieved when the particle size was between 0.3 and 1.5 mm. The present results provide theoretical support for the development of a highly efficient flotation separation for carbonate minerals.

  15. In situ fabricated iodine-adlayer assisted selective electrooxidation of uric acid in alkaline media

    Energy Technology Data Exchange (ETDEWEB)

    Miah, Md. Rezwan [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Mail Box G1-5, 4259 Nagastuta, Midori-ku, Yokohama 226-8502 (Japan)], E-mail: mrmche@yahoo.com; Masud, Jahangir [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Mail Box G1-5, 4259 Nagastuta, Midori-ku, Yokohama 226-8502 (Japan); Ohsaka, Takeo [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Mail Box G1-5, 4259 Nagastuta, Midori-ku, Yokohama 226-8502 (Japan)], E-mail: ohsaka@echem.titech.ac.jp

    2008-12-30

    This work presents the electrooxidation of uric acid (UA) at an iodine-adlayer-modified gold, Au (I|Au (poly)) electrode in 0.1 M NaOH solution using cyclic voltammetric, amperometric and open-circuit potential measurement techniques. A tremendous enhancement of the electrode activity towards the electrooxidation of UA was achieved by virtue of the simple modification of the Au (poly) electrode surface with a neutral iodine-adlayer, fabricated in situ through the spontaneous oxidative chemisorption of iodide present in the sample solution. The cyclic voltammetric peak current increases remarkably for the oxidation of UA and the peak potential shifts by 365 mV to the negative direction of potential compared to the bare Au (poly) electrode. Oxidation of ascorbic acid (AA) at the I|Au (poly) electrode takes place at the same potential as that at the bare electrode, but the peak current intensity is almost twice at the bare Au (poly) electrode as compared to the modified one. In the mixture of the AA and UA, the cyclic voltammetric signals corresponding to the oxidations of AA and UA were resolved by 340 mV. The electrode response in the mixture was highly reproducible because of the inhibition of adsorption of oxidation products and UA.

  16. Development of a chromatographic micro-system for radionuclides analysis in nitric acid media

    International Nuclear Information System (INIS)

    Losno, Marion

    2017-01-01

    Radionuclides analysis is a key point for nuclear waste management and nuclear material control. Several steps of sample modification have to be carried out before measurements in order to avoid any interferences and improve measurement precision. However those different steps are long, irradiating and difficult to achieve in gloveboxes. Moreover they produce liquid and solid waste. The goal of the study is to offer a new alternative to the use of solid phase extraction column for radionuclides separation in hard nitric acid medium. The system will decrease the amount of nuclear waste due to the analysis and automatize the different steps of the analysis. A plastic device made of COC containing a micro solid phase extraction column is first designed. Stationary phase is a poly(AMA-co-EDMA) monolith synthesized in situ. Its structure is adjustable and its functionalization versatile with a high resistance to nitric acid medium. Exchange capacity is 150 mg/g of monolith for TBP and TBP/CMPO column and up to 280 mg/g of monolith in case of DAAP. Exchange coefficients are determined for U(VI), Th(IV), Eu(III) and Nd(III) for 3 different extractants (and Pu(IV) in case of TBP column). Monolith synthesis is transferred in centrifugal device and hydrodynamic behavior studied. U,Th/Eu separation was finally carried out in both classic and centrifugal micro-system on TBP column. (author) [fr

  17. Studies on the Inhibition of Mild Steel Corrosion by Rauvolfia serpentina in Acid Media

    Science.gov (United States)

    Bothi Raja, P.; Sethuraman, M. G.

    2010-07-01

    Alkaloid extract of Rauvolfia serpentina was tested as corrosion inhibitor for mild steel in 1 M HCl and H2SO4 using weight loss method at three different temperatures, viz., 303, 313, and 323 K, potentiodynamic polarization, electrochemical impedance spectroscopy and scanning electron microscope (SEM) studies. It is evident from the results of this study that R. serpentina effectively inhibits the corrosion in both the acids through adsorption process following Tempkin adsorption isotherm. The protection efficiency increased with increase in inhibitor concentration and temperature. Free energy of adsorption calculated from the temperature studies also revealed the chemisorption. The mixed mode of action exhibited by the inhibitor was confirmed by the polarization studies while SEM analysis substantiated the formation of protective layer over the mild steel surface.

  18. Extraction of metals and/or metalloids from acidic media using supercritical fluids and salts

    International Nuclear Information System (INIS)

    Wai, C.M.; Smart, N.G.; Lin, Y.

    1998-01-01

    A method is described for extracting metalloid and metal species from a solid or liquid material by exposing the material to a fluid solvent, particularly supercritical carbon dioxide, containing a chelating agent. The chelating agent forms chelates that are soluble in the fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent comprises a trialkyl phosphate, a triaryl phosphate, a trialkylphosphine oxide, a triarylphosphine oxide, or mixtures thereof. The method provides an environmentally benign process for removing contaminants from industrial waste. The method is particularly useful for extracting actinides from acidic solutions, and the process can be aided by the addition of nitrate salts. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process. 7 figs

  19. Extraction of metals and/or metalloids from acidic media using supercritical fluids and salts

    Science.gov (United States)

    Wai, Chien M.; Smart, Neil G.; Lin, Yuehe

    1998-01-01

    A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a fluid solvent, particularly supercritical carbon dioxide, containing a chelating agent is described. The chelating agent forms chelates that are soluble in the fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent comprises a trialkyl phosphate, a triaryl phosphate, a trialkylphosphine oxide, a triarylphosphine oxide, or mixtures thereof. The method provides an environmentally benign process for removing contaminants from industrial waste. The method is particularly useful for extracting actinides from acidic solutions, and the process can be aided by the addition of nitrate salts. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process.

  20. Single Atomic Iron Catalysts for Oxygen Reduction in Acidic Media: Particle Size Control and Thermal Activation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hanguang [Department; Hwang, Sooyeon [Center; Wang, Maoyu [School; Feng, Zhenxing [School; Karakalos, Stavros [Department; Luo, Langli [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Qiao, Zhi [Department; Xie, Xiaohong [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Wang, Chongmin [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Su, Dong [Center; Shao, Yuyan [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Wu, Gang [Department

    2017-09-26

    To significantly reduce the cost of proton exchange membrane (PEM) fuel cells, current Pt must be replaced by platinum-metal-group (PGM)-free catalysts for the oxygen reduction reaction (ORR) in acid. We report here a new class of high-performance atomic iron dispersed carbon catalysts through controlled chemical doping of iron ions into zinc-zeolitic imidazolate framework (ZIF), a type of metal-organic framework (MOF). The novel synthetic chemistry enables accurate size control of Fe-doped ZIF catalyst particles with a wide range from 20 to 1000 nm without changing chemical properties, which provides a great opportunity to increase the density of active sites that is determined by the particle size. We elucidated the active site formation mechanism by correlating the chemical and structural changes with thermal activation process for the conversion from Fe-N4 complex containing hydrocarbon networks in ZIF to highly active FeNx sites embedded into carbon. A temperature of 800oC was identified as the critical point to start forming pyridinic nitrogen doping at the edge of the graphitized carbon planes. Further increasing heating temperature to 1100oC leads to increase of graphitic nitrogen, generating possible synergistic effect with FeNx sites to promote ORR activity. The best performing catalyst, which has well-defined particle size around 50 nm and abundance of atomic FeNx sites embedded into carbon structures, achieve a new performance milestone for the ORR in acid including a half-wave potential of 0.85 V vs RHE and only 20 mV loss after 10,000 cycles in O2 saturated H2SO4 electrolyte. The new class PGM-free catalyst with approaching activity to Pt holds great promise for future PEM fuel cells.

  1. Effects of Peptone Supplementation in Different Culture Media on Growth, Metabolic Pathway and Productivity of CHO DG44 Cells; a New Insight into Amino Acid Profiles.

    Science.gov (United States)

    Davami, Fatemeh; Eghbalpour, Farnaz; Nematollahi, Leila; Barkhordari, Farzaneh; Mahboudi, Fereidoun

    2015-01-01

    The optimization of bioprocess conditions towards improved growth profile and productivity yield is considered of great importance in biopharmaceutical manufacturing. Peptones as efficient sources of nutrients have been studied for their effect on media development; however, their role on metabolic pathway is not well understood. In the present study, the effect of different concentration of peptones on a recombinant Chinese hamster ovary (CHO) cell line grown in three serum-free suspension cultures was determined. Six peptones of different origins and available amino acid profiles were investigated regarding their impact on cell growth, productivity, and metabolic pathways changes. In optimized feeding strategies, increases of 136% and 159% in volumetric productivity (for a low-nutrient culture media) and 55% (for a high-nutrient culture media) were achieved. Furthermore, particular sources of peptones with specific amino acid profile developed preferential results for each different culture medium. Two peptones, SoyA2SC and SoyE-110, were the only hydrolysates that showed production improvement in all three media. Casein Peptone plus Tryptone N1 and SoyA3SC showed different improved results based on their implemented concentration for each individual basal medium. The amino acid profile of peptones may provide clues to identify the most effective feeding strategies for recombinant CHO cells.

  2. Ultrasound augmented leaching of nickel sulfate in sulfuric acid and hydrogen peroxide media.

    Science.gov (United States)

    Li, Haoyu; Li, Shiwei; Peng, Jinhui; Srinivasakannan, Chandrasekar; Zhang, Libo; Yin, Shaohua

    2018-01-01

    A new method of preparation high purity nickel sulfate assisted by ultrasonic was studied. The process mechanism was analyzed by Inductively Coupled Plasma (ICP), X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Energy dispersive X-ray spectrometry (EDS).The reaction mechanisms of oxidizing leaching and ultrasonic leaching were explored, respectively. Results showed that ultrasonic treatment peel off the oxide film on the surface of nickel. The leachate under strongly agitated, the yield rate of nickel sulfate was accelerate. And the reaction area was increased by the cavitation effect, the liquid-solid reaction was promoted, and the activation energy was reduced. The leaching rate of nickel reached 46.29% by conventional leaching, which takes about 5h. Under the same conditions, the ultrasonic leaching rate reached 40%, only half of the conventional leaching time. Concentration of leaching agent, reaction temperature, ultrasonic power, leaching time had significant effect on the enhancement of the leaching reaction with ultrasonic radiation. The leaching rate of 60.41% under the optimum experiment conditions as follows: sulfuric acid concentration 30%, hydrogen peroxide 10%, leaching temperature 333K, ultrasonic power 200W and leaching time 4h. The kinetic study of the system was investigated, and the reaction rates of conventional leaching and ultrasonic leaching were controlled by diffusion, and the apparent activation energies were 16.2kJ/mol and 11.83kJ/mol. Copyright © 2017. Published by Elsevier B.V.

  3. Decomposition of clofibric acid in aqueous media by advance oxidation techniques: kinetics study and degradation pathway

    International Nuclear Information System (INIS)

    Syed, M.; Khan, A.M.; Khan, R.A.

    2016-01-01

    This study investigates the decomposition of clofibric acid (CLF) by different advanced oxidation processes (AOPs), such as UV (254 nm), VUV (185 nm), UV / TiO/sub 2/ and VUV / TiO/sub 2/. The removal efficiencies of applied AOPs were compared in the presence and absence of dissolved oxygen. The removal efficiency of the studied AOPs towards degradation of CLF were found in the order of VUV / TiO/sub 2/ + O/sub 2/ > VUV/TiO/sub 2/ + N/sub 2/ > VUV alone > UV / TiO/sub 2/ + O/sub 2/ > UV / TiO/sub 2/ +N/sub 2/ > UV alone. The decomposition kinetics of CLF was found to follow pseudo-first order rate law. VUV / TiO2 process was found to be most cheap and effective one for decomposition of CLF as compared to other applied AOPs in terms of electrical energy per order. Degradation products resulting from the degradation processes were also investigated using UPLC-MS /MS, accordingly degradation pathway was proposed. (author)

  4. Corrosion behaviour of WC-Co based hardmetal in neutral chloride and acid sulphate media

    Energy Technology Data Exchange (ETDEWEB)

    Bozzini, B.; Serra, M.; Fanigliulo, A.; Bogani, F. [Lecce Univ. (Italy). Dipt. di Ingegneria dell' Innovazione; Gaudenzi, G.P. de [Harditalia s.r.l. (OMCD Group), Genova (Italy)

    2002-05-01

    A comparative study of the corrosion behaviour of WC-Co based hardmetals with Ni and Cr{sub 3}C{sub 2} additions is carried out. The aggressive environments are neutral and acidic aerated aqueous solutions of NaCl and H{sub 2}SO{sub 4}. This study is based on electrochemical (linear sweep voltammery), compositional (surface EDX analyses, AAS analyses of attack solutions), structural (XRD) and morphological (SEM) investigations. Electrochemical figures of merit were computed from linear sweep voltammograms in order to rank the corrosion behaviour close to free-immersion conditions in the studied environments and with presence of oxidising agents. EDX and XRD analyses allow to accurately characterise the penetration depth of the attack as well as the preferential dissolution of the constituents. Binders containing Ni show a significantly improved corrosion resistance in the studied systems. The amount of Ni in the binder is the single most important factor affecting corrosion performance. Cr{sub 3}C{sub 2} additions to hardmetals with lower-Ni binders cannot balance the effect of Ni, but give an improved resistance in neutral chloride-containing solutions. (orig.)

  5. Behavior of soluble and immobilized acid phosphatase in hydro-organic media.

    Science.gov (United States)

    Wan, H; Horvath, C

    1975-11-20

    The hydrolysis of p-nitrophenyl phosphate by wheat germ acid phosphatase (orthophosphoric monoester phosphohydrolase, EC 3.1.3.2) has been investigated in mixtures of aqueous buffers with acetone, dioxane and acetonitrile. The enzyme was either in free solution or immobilized on a pellicular support which consisted of a porous carbonaceous layer on solid glass beads. The highest enzyme activity was obtained in acetone and acetonitrile mixed with citrate buffer over a wide range of organic solvent concentration. In 50% (v/v) acetone both V and Km of the immobilized enzyme were about half of the values in the neat aqueous buffer, but the Ki for inorganic phosphate was unchanged. In 50% (v/v) mixtures of various solvents and citrate buffers of different pH, the enzymic activity was found to depend on the pH of the aqueous buffer component rather than the pH of the hydro-organic mixture as measured with the glass-calomel electrode. The relatively high rates of p-nitrophenol liberation in the presence of glucose even at high organic solvent concentrations suggest that transphosphorylation is facilitated at low water activity.

  6. Organic compounds as corrosion inhibitors for mild steel in acidic media: correlation between inhibition efficiency and chemical structure

    Energy Technology Data Exchange (ETDEWEB)

    Elias, Elizandra C.S.; Chrisman, Erika C.A.N. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Escola de Quimica

    2009-12-19

    The use of inhibitors for mild steels corrosion control which are in contact with aggressive environment is an accepted practice in acid treatment of oil-wells. Organic compounds have been studied to evaluate their corrosion inhibition potential. Film-forming corrosion inhibitors, commonly used to protect oil-field equipment, can be absorbed on the steel surface to give structurally ordered layers. Therefore, the electrons should act as an important role for this adsorption. Studies reveal that organic compounds show significant inhibition efficiency. For this purpose, their molecules should contain N, O and S heteroatoms in various functional groups, long hydrocarbon linear or branched radical and anion and cation active components. However, most of these compounds are not only expensive but also toxic to living beings. According to the 'Green Chemistry' rules, corrosion inhibitors based on organic compounds should be cheap, with low toxicity and have high inhibition efficiency. In this study, the effects of some organic compounds with different groups such as amide, ether, phenyldiamine, anime and aminophenol on the corrosion behavior of mild steel in acidic media have been investigated. The experimental data were obtained by gravimetric measurements. The results show that these compounds reveal a promising corrosion inhibition where phenyldiamine is the most efficient. The effect of molecular structure on the corrosion inhibition efficiency was investigated by semi-empirical quantum chemical calculations. The electronic properties such as highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) energy levels, and LUMO-HOMO energy gap orbital density were calculated. The relations between the inhibition efficiency and some quantum parameters are discussed and correlations are proposed. The highest values for the HOMO densities were found in the vicinity nitrogen atom, indicating that it is the most probable adsorption center

  7. Spectrophotometric assay of pioglitazone hydrochloride using permanganate in acidic and basic media

    Directory of Open Access Journals (Sweden)

    Kanakapura Basavaiah

    2018-04-01

    Full Text Available Pioglitazone hydrochloride (PGH is an oral anti-hyperglycemic agent used in the treatment of type-2 diabetes mellitus. Potassium permanganate was found to oxidize PGH both in acidic and basic conditions, based on which two simple and sensitive methods were developed for its determination in bulk sample and tablets, and validated. In the first method (indirect method, PGH was reacted with a measured excess of standard permanganate in H2SO4 medium, and the residual oxidant was determined by measuring its absorbance at 550 nm. The second method (Direct method entails treating PGH with permanganate in NaOH medium, followed by the measurement of the resulting bluish-green manganite at 610 nm. Experimental variables affecting the reactions were studied and optimized. Under optimum conditions, linear relationships with good correlation coefficients were found between absorbance and concentration in the ranges, 1.25 – 25 µg mL-1 (Indirect method and 1-12 µg mL-1 (Direct method with respective molar absorptivity values of 1.10 × 104 and 2.77 × 104 l mol-1 cm-1. The limits of detection (LOD and quantification (LOQ were 0.36 and 1.08 (Indirect method and 0.23 and 0.69 µg mL-1 (Direct method. Intra-day and inter-day precisions were satisfactory, with %RSD values of ≤2.11, and the respective accuracies were excellent with %RE values of ≤2. The methods were also validated for robustness, ruggedness and selectivity. The methods were applied to the determination of PGH in its tablets with good accuracy and precision, and no interference from the tablet additives was encountered. The results were also compared with those obtained by a reference method.

  8. Predicting the combinatorial effects of water activity, pH and organic acids on Listeria growth in media and complex food matrices.

    Science.gov (United States)

    Nyhan, L; Begley, M; Mutel, A; Qu, Y; Johnson, N; Callanan, M

    2018-09-01

    The aim of this study was to develop a model to predict growth of Listeria in complex food matrices as a function of pH, water activity and undissociated acetic and propionic acid concentration i.e. common food hurdles. Experimental growth curves of Listeria in food products and broth media were collected from ComBase, the literature and industry sources from which a bespoke secondary gamma model was constructed. Model performance was evaluated by comparing predictions to measured growth rates in growth media (BHI broth) and two adjusted food matrices (zucchini purée and béarnaise sauce). In general, observed growth rates were higher in broth than in the food matrices which resulted in the model over-estimating growth in the adjusted food matrices. In addition, model outputs were more accurate for conditions without acids, indicating that the organic acid component of the model was a source of inaccuracy. In summary, a new predictive growth model for innovating or renovating food products that rely on multi-hurdle technology was created. This study is the first to report on modelling of propionic acid as an inhibitor of Listeria in combination with other hurdles. Our findings provide valuable insights into predictive model design and performance and highlight the importance of experimental validation of models in real food matrices rather than laboratory media alone. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Effect of Al and Ce oxide layers electrodeposited on OC4004 stainless steel on its corrosion characteristics in acid media

    International Nuclear Information System (INIS)

    Stoyanova, E.; Nikolova, D.; Stoychev, D.; Stefanov, P.; Marinova, T.

    2006-01-01

    The changes in the corrosion characteristics of stainless steel OC4004 in 0.1 M HNO 3 after electrodeposition of thin Al and Ce oxide films on it has been investigated. The Ce 2 O 3 -CeO 2 layers have been found to possess a pronounced stabilizing effect on the steel passive state and on its corrosion resistance, respectively, whereas the Al 2 O 3 layers do not improve considerably the corrosion behaviour of the SS/Al 2 O 3 system. A twice-lower corrosion current was observed with a ternary SS/Al 2 O 3 /Ce 2 O 3 -CeO 2 system in the passive region, while the zones of potentials, where the steel is in a stable passive state, are not changed. The obtained results permit the assumption that the cerium oxides layer acts as an effective cathode playing a determining role with respect to the improvement of the corrosion behavior of the steel. It has been concluded that when the SS/Al 2 O 3 /Ce 2 O 3 -CeO 2 system is used in media containing nitric acid, the corrosion will proceed at potentials where the passive state of steel would not be disturbed

  10. Solvent extraction of uranium(VI) and thorium(IV) from nitrate media by carboxylic acid amides

    International Nuclear Information System (INIS)

    Preston, J.S.; Preez, A.C. du

    1995-01-01

    A series of nineteen N-alkyl carboxylic acid amides (R.CO.NHR') has been prepared, in which the alkyl groups R and R' have been varied in order to introduce different degrees of steric complexity into the compounds. A smaller number of N,N-dialkyl amides (R.CO.NR 2 ') and non-substituted amides (R.CO.NH 2 ) has also been prepared for comparison purposes. These amides were characterized by measurement of their boiling points, melting points, refractive indices and densities. The solvent extraction of uranium(VI) and thorium(IV) from sodium nitrate media by solutions of the amides in toluene was studied. Increasing steric bulk of the alkyl groups R and R' was found to cause a marked decrease in the extraction of thorium, with a much smaller effect on the extraction of uranium, thus considerably enhancing the separation between these metals. Vapour pressure osmometry studies indicate that the N-alkyl amides are self-associated in toluene solution, with aggregation numbers up to about 2.5 for 0.6 M solutions at 35 degree C. In contrast, the N,N-dialkyl amides behave as monomers under these conditions. The distribution ratios for the extraction of uranium and thorium show second- and third-order dependences, respectively, on the extractant concentration for both the N-alkyl and N,N-dialkyl amides. 15 refs., 8 figs., 8 tabs

  11. Am and Eu extraction from acidic media by synergistic mixtures of substituted bis-tetrazolyl pyridines with chlorinated cobalt dicarbollide

    International Nuclear Information System (INIS)

    Smirnov, I.V.; Chirkov, A.V.; Babain, V.A.; Pokrovskaya, E.Yu.; Artamonova, T.A.

    2009-01-01

    Americium (Am) and europium (Eu) extraction from HNO 3 and HClO 4 media by a synergistic mixture of 2.6-bis(1-aryl-1H-tetrazol-5-yl)pyridines (ATP) with chlorinated cobalt dicarbollide (CCD) was studied by using m-nitrobenzotrifluoride, phenyltrifluoromethyl sulfone, and 1,2-dichloroethane as diluents. We examined the effects of diluents, of the aqueous phase composition and the nature of substituents in the ATP aryl ring on Am/Eu extraction efficiency and selectivity. The Am/Eu separation factor was found to be close to 100 at the optimal ratio of ATPs: CCD ∝ 1:1. We also studied the extraction of 85 Sr, 137 Cs and 133 Ba; a PhATP-CCD mixture provided the separation of the Sr/Ba pair with a factor of 35. A high resistance of 2,6-bis-aryltetrazolyl pyridines to 6 M nitric and perchloric acids at 95 C was demonstrated. (orig.)

  12. Effect of Aquo-glycolic Media and Added Anions on the Anodization of Zircaloy-4 in Sulphamic Acid

    Directory of Open Access Journals (Sweden)

    Viplav Duth Shukla

    2011-01-01

    Full Text Available Anodization of zircaloy-4 in 0.1 M sulphamic acid has been carried out. Kinetics of anodic oxidation of zircaloy-4 has been studied at a constant current density of 8 mA/cm2 and at room temperature. Thickness estimates were made from capacitance data. The plots of formation voltage vs. time, reciprocal capacitance vs. time, reciprocal capacitance vs. formation voltage and thickness vs. formation voltage were drawn and rate of formation, current efficiency and differential field were calculated. The addition of solvent (ethylene glycol showed better kinetic results. For 25%, 50% and 75% aquo-glycolic media, the dielectric constant values are low leading to a marked improvement in the kinetics. In 80% ethylene glycol, though the dielectric constant value of solution is less, the kinetics was slow which may be attributed to the fact that the electrolyte becomes highly non-polar. Improvement in the kinetics of oxide film formation was observed by the addition of millimolar concentration of anions (CO32-, SO42-, PO43-. The presence of phosphate ions improved the kinetics of anodization to better extent.

  13. Removal of CdTe in acidic media by magnetic ion-exchange resin: A potential recycling methodology for cadmium telluride photovoltaic waste

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Teng, E-mail: zhangteng@mail.iee.ac.cn; Dong, Zebin; Qu, Fei; Ding, Fazhu; Peng, Xingyu; Wang, Hongyan; Gu, Hongwei

    2014-08-30

    Highlights: • Sulfonated magnetic microsphere was prepared as one strong acid cation-exchange resin. • Cd and Te can be removed directly from the highly acidic leaching solution of CdTe. • Good chemical stability, fast adsorbing rate and quick magnetic separation in strong acidic media. • A potential path for recycling CdTe photovoltaic waste. - Abstract: Sulfonated magnetic microspheres (PSt-DVB-SNa MPs) have been successfully prepared as adsorbents via an aqueous suspension polymerization of styrene-divinylbenzene and a sulfonation reaction successively. The resulting adsorbents were confirmed by means of Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS) and vibrating sample magnetometer (VSM). The leaching process of CdTe was optimized, and the removal efficiency of Cd and Te from the leaching solution was investigated. The adsorbents could directly remove all cations of Cd and Te from a highly acidic leaching solution of CdTe. The adsorption process for Cd and Te reached equilibrium in a few minutes and this process highly depended on the dosage of adsorbents and the affinity of sulfonate groups with cations. Because of its good adsorption capacity in strong acidic media, high adsorbing rate, and efficient magnetic separation from the solution, PSt-DVB-SNa MPs is expected to be an ideal material for the recycling of CdTe photovoltaic waste.

  14. Monitoring utilizations of amino acids and vitamins in culture media and Chinese hamster ovary cells by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Qiu, Jinshu; Chan, Pik Kay; Bondarenko, Pavel V

    2016-01-05

    Monitoring amino acids and vitamins is important for understanding human health, food nutrition and the culture of mammalian cells used to produce therapeutic proteins in biotechnology. A method including ion pairing reversed-phase liquid chromatography with tandem mass spectrometry was developed and optimized to quantify 21 amino acids and 9 water-soluble vitamins in Chinese hamster ovary (CHO) cells and culture media. By optimizing the chromatographic separation, scan time, monitoring time window, and sample preparation procedure, and using isotopically labeled (13)C, (15)N and (2)H internal standards, low limits of quantitation (≤0.054 mg/L), good precision (culture media. In a fed-batch process of manufacturing scale bioreactors, two distinguished trends for changes in amino acid concentrations were identified in response to feeding. Ten essential amino acids showed a zigzag pattern with maxima at the feeding days, and 9 non-essential amino acids displayed a smoothly changing profile as they were mainly products of cellular metabolism. Five of 9 vitamins accumulated continuously during the culture period, suggesting that they were fed in access. The method serves as an effective tool for the development and optimization of mammalian cell cultures. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Whole Blood ω-3 Fatty Acids Are Inversely Associated with Carotid Intima-Media Thickness in Indigenous Mexican Women.

    Science.gov (United States)

    Monge, Adriana; Harris, William S; Ortiz-Panozo, Eduardo; Yunes, Elsa; Cantu-Brito, Carlos; Catzin-Kuhlmann, Andres; López-Ridaura, Ruy; Lajous, Martín

    2016-07-01

    Long-chain ω-3 (n-3) polyunsaturated fatty acids (PUFAs) may reduce the risk of atherosclerosis. The association between n-3 PUFAs and cardiovascular disease may vary across different populations, and there is limited information on Hispanic individuals with mixed Amerindian and European origin. We evaluated the cross-sectional relations between whole blood n-3 PUFAs and carotid intima-media thickness (IMT) in Mexican women living in Mexico and assessed whether this relation was different in women who spoke an indigenous language compared with women who did not. In 2012-2013, we assessed the association between blood n-3 PUFAs and IMT in 1306 women free of disease in Chiapas and Yucatan, Mexico. We categorized blood n-3 PUFAs (% of total FAs) in quartiles and adjusted linear regression models by age, indigenous language, site, socioeconomic status, education, smoking, menopause, diabetes, hypertension, hypercholesterolemia, body mass index, physical activity, and diet. We stratified analyses by indigenous/nonindigenous language speakers (n = 315 of 991). Whole blood n-3 PUFAs (means ± SDs) were 3.58% ± 0.78% of total FAs. We did not observe a significant association between n-3 PUFAs and IMT in the overall study population. However, the adjusted mean difference of IMT was -6.5% (95% CI: -10.7%, -2.3%; P-trend women in the highest quartile compared with the lowest quartile of blood n-3 PUFAs. In nonindigenous women, we did not observe an association (-0.6%; 95% CI: -3.0%, 1.8%, comparing extreme quartiles; P-trend = 1.00). Overall, circulating n-3 PUFAs were not associated with IMT. However, we observed a strong statistically significant inverse association with IMT in indigenous Mexican women. Future studies should evaluate genetic markers that may reflect differences in n-3 PUFA metabolism across populations. © 2016 American Society for Nutrition.

  16. Association of branched-chain amino acids with carotid intima-media thickness and coronary artery disease risk factors.

    Directory of Open Access Journals (Sweden)

    Ruiyue Yang

    Full Text Available BACKGROUND: Recent studies have determined that branched-chain (BCAAs and aromatic (AAAs amino acids are strongly correlated with obesity and atherogenic dyslipidemia and are strong predictors of diabetes. However, it is not clear if these amino acids are capable of identifying subjects with coronary artery disease (CAD, particularly with subclinical atherosclerosis who are at risk of developing CAD. METHODS: Four hundred and seventy two Chinese subjects (272 males and 200 females, 42-97 y of age undergoing physical exams were recruited at random for participation in the cross-sectional study. Serum BCAAs and AAAs were measured using our previously reported isotope dilution liquid chromatography tandem mass spectrometry method. Bilateral B-mode carotid artery images for carotid intima-media thickness (cIMT were acquired at end diastole and cIMT values more than 0.9 mm were categorized as increased. Correlations of BCAAs with cIMT and other CAD risk factors were analyzed. RESULTS: BCAAs and AAAs were significantly and positively associated with risk factors of CAD, e.g., cIMT, BMI, waist circumference, blood pressure, fasting blood glucose, TG, apoB, apoB/apoAI ratio, apoCII, apoCIII and hsCRP, and were significantly and negatively associated with HDL-C and apoAI. Stepwise multiple linear regression analysis revealed that age (β = 0.175, P<0.001, log BCAA (β = 0.147, P<0.001 and systolic blood pressure (β = 0.141, P = 0.012 were positively and independently associated with cIMT. In the logistic regression model, the most and only powerful laboratory factor correlated with increased cIMT was BCAA (the odds ratio of the fourth quartile compared to the first quartile was 2.679; P = 0.009. CONCLUSION: BCAAs are independently correlated with increased cIMT. This correlation would open a new field of research in the mechanistic understanding and risk assessment of CAD.

  17. The development of a method for the simultaneous measurement of cerium (IV) and chromium (VI) species in nitric acid media - 16124

    International Nuclear Information System (INIS)

    Nickson, Ian D.; Boxall, Colin; Jackson, Angela; Whillock, Guy O.H.

    2009-01-01

    The corrosion of stainless steel in nitric acid media is a major concern for the nuclear industry. Several reprocessing schemes such as PUREX (Plutonium Uranium Reduction Extraction) and UREX (Uranium Reduction Extraction) utilise nitric acid media, and an understanding of the behaviour of key chemical species in these process streams is vital if their effect on associated corrosion reactions and their rates is to be accurately assessed and quantified. This will allow for more accurate prediction of the working lifetime of any stainless steel surface in contact with the process stream in question. Two such key species that are found in nuclear process streams are cerium as Ce (IV) and chromium as Cr(VI), both of which may act as corrosion accelerants. The redox chemistry of cerium and chromium in highly active liquor (HAL) will depend on nitrous acid concentration, temperature, acidity, total nitrate and possibly the influence of other dissolved species and hence an analytical technique for the on-line measurement of these quantities would be useful for lifetime prediction and corrosion prevention. As a result of this, a strategy for the simultaneous measurement of both Ce(IV) and Cr(VI) species in the presence of other ions typically found in process streams (such as Iron, Magnesium Neodymium and Aluminium) has been developed. The work presented will discuss the design and implementation of the electrochemical techniques that we have used in the development of this strategy and in the measurement of the species in question. (authors)

  18. Conductimetric and Potentiometric Titration of Some Hydroxylated Cinnamic Acids with Tetrabutylammonium Hydroxide in Non-Aqueous Media

    OpenAIRE

    AKTAŞ, A. Hakan; YAŞAR, Gülsüm; ALSANCAK, Güleren ÖZKAN

    2001-01-01

    In this study, four hydroxycinnamic acids, namely 3,4-dihydroxycinnamic acid, 4-hydroxycinnamic acid, 4-hydroxy --3- methoxycinnamic acid and 4-hydroxy-3,5-dimethoxycinnamic acid, were titrated conductimetrically and potentiometrically using triethylamine and tetrabutylammonium hydroxide in acetonitrile, 2-propanol, and pyridine solvents under a nitrogen atmosphere at 25 oC. In conductimetric titration with tetrabutylammonium hydroxide all of the compounds exhibited conventional s...

  19. Fermentative activity and production of volatile compounds by Saccharomyces grown in synthetic grape juice media deficient in assimilable nitrogen and/or pantothenic acid.

    Science.gov (United States)

    Wang, X D; Bohlscheid, J C; Edwards, C G

    2003-01-01

    To understand the impact of assimilable nitrogen and pantothenic acid on fermentation rate and synthesis of volatile compounds by Saccharomyces under fermentative conditions. A 2 x 3 factorial experimental design was employed with the concentrations of yeast assimilable nitrogen (YAN) (60 and 250 mg l(-1)) and pantothenic acid (10, 50 and 250 microg l(-1)) as variables. In media containing 250 microg l(-1) pantothenic acid, H2S production by two different species of Saccharomyces decreased when YAN was increased from 60 to 250 mg l(-1). Conversely, H2S production was significantly higher when the concentration of assimilable nitrogen was increased if pantothenic acid was deficient (10 or 50 microg l(-1)). Yeast synthesis of other volatile compounds were impacted by both assimilable nitrogen and pantothenic acid. While growth and fermentative rate of Saccharomyces was more influenced by nitrogen than by pantothenic acid, complicated interactions exist between these nutrients that affect the synthesis of volatile compounds including H2S. This study has important implications for the winemaking industry where a better understanding of the nutritional requirements of Saccharomyces is necessary to reduce fermentation problems and to improve final product quality.

  20. A study on the alkalimetric titration with gran plot in noncomplexing media for the determination of free acid in spent fuel solutions

    International Nuclear Information System (INIS)

    Suh, Moo Yul; Lee, Chang Heon; Sohn, Se Chul; Kim, Jung Suk; Kim, Won Ho; Eom, Tae Yoon

    1999-01-01

    Based on the study of hydrolysis behaviour of U(VI) ion and major fission product metal ions such as Cs(I), Ce(III), Nd(III), Mo(VI), Ru(II), and Zr(VI) in the titration media, the performance of noncomplexing-alkalimetric titration method for the determination of free acid in the presence of these metal ions was investigated and its results were compared to those from the complexing methods. The free acidities could be determined as low as 0.05 meq in uranium solutions in which the molar ratio of U(VI)/H + was less than 5, when the end-point of titration was estimated by Gran plot. The biases in the determinations were less than ±1% and about +3% respectively for 0.4 meq and 0.05 meq of free acid at the U(VI)/H + molar ratio of up to 5. Applicability of this method to the determination of free acid in spent fuel solutions was confirmed by the analysis of nitric acid content in simulated spent fuel solutions and in a real spent fuel solution

  1. Selective extraction of palladium with caffeine from acidic chloride media; Sansei enkabutsu yoeki karano kafuein ni yoru parajiumu no sentakuteki chushutsu

    Energy Technology Data Exchange (ETDEWEB)

    Kaikake, K.; Baba, Y. [Miyazaki University, Miyazaki (Japan). Faculty of Engineering

    1999-06-10

    In order to examine the possibility of caffeine as an extractant, the extraction of metal ions from acidic chloride media was studied at 298 K using the mixture solvent of chloroform and 2-ethyl-1-hexanol. Caffeine has exhibited a high selectivity for palladium (2) over base metals such as copper (2), nickel (2), and iron (3), and over precious metal such as platinum (4). The stoichiometric relation in the extraction of palladium (2) with caffeine was elucidated by examining the effects of chloride ion, hydrogen ion, and caffeine concentrations on its extractability. In addition, palladium (2) was found to be extracted selectively with caffeine from the mixture containing a 25-fold amount of platinum (4) or copper (2). The stripping of palladium (2) was performed to an extent of 80% by a single batchwise treatment with an aqueous mixture solution of hydrochloric acid and thiourea. (author)

  2. Electroactivity of cobalt and nickel glyoximes with regard to the electro-reduction of protons into molecular hydrogen in acidic media

    Energy Technology Data Exchange (ETDEWEB)

    Pantani, O.; Anxolabehere-Mallart, E.; Aukauloo, A. [Equipe de Chimie Inorganique, Institut de Chimie Moleculaire et des Materiaux d' Orsay, UMR 8182, Universite Paris Sud, bat 420, 91405 Orsay Cedex (France); Millet, P. [Equipe de Physico-Chimie de l' Etat Solide, Institut de Chimie Moleculaire et des Materiaux d' Orsay, UMR 8182, Universite Paris Sud, bat 420, 91405 Orsay Cedex (France)

    2007-01-15

    Water electrolysis is a key technological process for the production of hydrogen and the storage of intermittent and renewable energy sources. For domestic applications, the proton exchange membrane (PEM) process provides a safe and efficient way to split water into molecular hydrogen and oxygen but this technology, which requires platinum family electro-catalysts, remains too expensive. Molecular chemistry offers new opportunities for synthesizing alternative low-cost compounds, sufficiently stable in strong acidic media. In this paper, results obtained with different nickel and cobalt glyoximes are presented. They have been chemically (using UV-visible spectroscopy) and electrochemically (using cyclic voltammetry and spectro-electrochemistry) characterized. Their ability to electroreduce protons into molecular hydrogen from aqueous acidic solutions is discussed, the compounds being either dissolved in solution or immobilized at the surface of a solid electrode using recast Nafion{sup (R)} films in view of PEM applications. (author)

  3. Growth and development of moringa (Moringa oleifera L. stem cuttings as affected by diameter magnitude, growth media, and indole-3-butyric acid

    Directory of Open Access Journals (Sweden)

    Shamsuddeen Rufai

    2016-12-01

    Full Text Available The acknowledged status of Moringa oleifera L. in sub-Saharan Africa, especially western Africa, has of recent accorded it the significance of being a good source of income to a large segment of many of its populace. Intensification of research into the realization of its full economic potential will be of utmost value to impoverished societies globally. One way to achieve this is the full exploration of all possible means that will facilitate its successful growth, propagation, and domestication. Even though it can be successfully raised through seeds, the high level outcrossing (64.3% observed is a hindrance to realization of true to type trees. Vegetative propagation can be employed as an option to tackle the noted limitation, ease the cultivation process, and achieve the required realization of its economic potential. Our trial was carried out to study the influence of two growth media and three levels of indole 3-butyric acid (IBA on root and shoot development in cuttings taken from a coppiced moringa tree existent in Universiti Putra Malaysia. Semi-hardwood cuttings of moringa, of between 20 and 30 mm diameter, cut into 25 cm length, were obtained, rinsed with a fungicide, then dipped, through their basal portion, inside varying levels (0, 1000, 2000, and 3000 ppm of indole-3-butyric acid (IBA for between 7 and 10 seconds. The treated cuttings were then transplanted into a polyethylene bags (23 cm × 36 cm, containing two growth media - a munchong series soil (M and a combination of a munchong series soil thoroughly mixed with biochar (MB in a 3:1 ratio sequence. The trial was conducted inside a shade house where the humidity of the experimental area was manipulated through a regular daily manual hand sprinkling. Plant height, percentage of primary branch produced, leaf area, and dry matter (DM were found to be significantly (P<0.05 influenced by variation in stem diameter magnitude, while the diameter of the primary branch and spad

  4. Acid-Base Equilibria of Some N-Substituted Thiophene-2-Carboxamidoximes in Non-Aqueous Media

    OpenAIRE

    DÜRÜST, Nedime

    2002-01-01

    The protonation constants of the amino nitrogens of some N-substituted thiophene-2-carboxamidoximes have been determined in acetic acid by means of potentiometric titration with perchloric acid. pKa values of the title compounds were interpreted on the basis of structural effects due to the substituents and the main skeleton.

  5. Fourier transform infrared spectroscopy for the prediction of fatty acid profiles in Mucor fungi grown in media with different carbon sources.

    Science.gov (United States)

    Shapaval, Volha; Afseth, Nils Kristian; Vogt, Gjermund; Kohler, Achim

    2014-09-11

    Fungal production of polyunsaturated fatty acids (PUFAs) is a highly potential approach in biotechnology. Currently the main focus is directed towards screening of hundreds strains in order to select of few potential ones. Thus, a reliable method for screening a high number of strains within a short period of time is needed. Here, we present a novel method for screening of PUFA-producing fungi by high-throughput microcultivation and FTIR spectroscopy. In the study selected Mucor fungi were grown in media with different carbon sources and fatty acid profiles were predicted on the basis of the obtained spectral data. FTIR spectra were calibrated against fatty acid analysis by GC-FD. The calibration models were cross-validated and correlation coefficients (R2) from 0.71 to 0.78 with RMSECV (root mean squared error) from 2.86% to 6.96% (percentage of total fat) were obtained. The FTIR results show a strong correlation to the results obtained by GC analysis, where high total contents of unsaturated fatty acids (both PUFA and MUFA) were achieved for Mucor plumbeus VI02019 cultivated in canola, olive and sunflower oil and Mucor hiemalis VI01993 cultivated in canola and olive oil.

  6. Investigation of adsorption and inhibitive effect of acid red GRE (183 dye on the corrosion of carbon steel in hydrochloric acid media

    Directory of Open Access Journals (Sweden)

    M. Abd El-raouf

    2015-09-01

    Full Text Available The adsorption and corrosion inhibitive effect of acid red GRE (183 dye on carbon steel alloy in 1 M HCl solutions was studied using various techniques. Results of weight loss, Tafel polarization measurements and electrochemical impedance spectroscopy (EIS techniques show that this compound has fairly good inhibiting properties for steel corrosion in acidic bath; with efficiency around 96% at a concentration of 50 ppm. The inhibition is of a mixed anodic–cathodic nature. Factors affecting the corrosion process have been calculated and discussed. Acid red GRE (183 dye was shown to be an inhibitor in the acidic corrosion. Inhibition efficiency increased with acid red GRE (183 dye concentration but decreased with rise in temperature, corrosion inhibition is attributed to the adsorption of acid red GRE (183 dye on the carbon steel surface via a physical adsorption mechanism. Langmuir isotherm is found to provide an accurate description of the adsorption behavior of the investigated azo compound. The nature of the protective film was investigated using SEM and EDX techniques.

  7. Oxidative leaching process with cupric ion in hydrochloric acid media for recovery of Pd and Rh from spent catalytic converters

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, C.A., E-mail: carlos.nogueira@lneg.pt [Laboratório Nacional de Energia e Geologia, I.P., Campus do Lumiar, 1649-038 Lisboa (Portugal); Paiva, A.P., E-mail: appaiva@fc.ul.pt [Centro de Química e Bioquímica, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa (Portugal); Oliveira, P.C. [Laboratório Nacional de Energia e Geologia, I.P., Campus do Lumiar, 1649-038 Lisboa (Portugal); Costa, M.C., E-mail: mcorada@ualg.pt [Centro de Ciências do Mar, Departamento de Química e Farmácia, Faculdade de Ciências e de Tecnologia, Campus de Gambelas, 8005-139 Faro (Portugal); Costa, A.M. Rosa da, E-mail: amcosta@ualg.pt [Centro de Investigação em Química do Algarve, Departamento de Química e Farmácia, Faculdade de Ciências e de Tecnologia, Campus de Gambelas, 8005-139 Faro (Portugal)

    2014-08-15

    Highlights: • A new leaching process based on Cu{sup 2+}/HCl media for recovering Pd and Rh from spent autocatalytic converters is presented. • Palladium and rhodium were efficiently leached, with attained maximum yields of 95% and 86%, respectively. • Temperature, time, and HCl and Cu{sup 2+} concentrations were found to be significant factors in the leaching of Pd and Rh. - Abstract: The recycling of platinum-group metals from wastes such as autocatalytic converters is getting growing attention due to the scarcity of these precious metals and the market pressure originated by increase of demand in current and emerging applications. Hydrometallurgical treatment of such wastes is an alternative way to the most usual pyrometallurgical processes based on smelter operations. This paper focuses on the development of a leaching process using cupric chloride as oxidising agent, in HCl media, for recovery of palladium and rhodium from a spent catalyst. The chloride media allows the adequate conditions for oxidising and solubilising the metals, as demonstrated by equilibrium calculations based on thermodynamic data. The experimental study of the leaching process revealed that Pd solubilisation is clearly easier than that of Rh. The factors temperature, time, and HCl and Cu{sup 2+} concentrations were significant regarding Pd and Rh leaching, the latter requiring higher factor values to achieve the same results. Leaching yields of 95% Pd and 86% Rh were achieved under optimised conditions (T = 80 °C, t = 4 h, [HCl] = 6 M, [Cu{sup 2+}] = 0.3 M)

  8. Corrosion Inhibition and Adsorption Properties of Ethanolic Extract of Calotropis for Corrosion of Aluminium in Acidic Media

    OpenAIRE

    Sudesh Kumar; Suraj Prakash Mathur

    2013-01-01

    The corrosion inhibition of aluminium in sulfuric acid solution in the presence of different plant parts, namely, leaves, latex, and fruit was studied using weight loss method and thermometric method. The ethanolic extracts of Calotropis procera and Calotropis gigantea act as an inhibitor in the acid environment. The inhibition efficiency increases with increase in inhibitor concentration. The plant parts inhibit aluminium, and inhibition is attributed, due to the adsorption of the plant part...

  9. Biochar as porous media for thermally-induced non-catalytic transesterification to synthesize fatty acid ethyl esters from coconut oil

    International Nuclear Information System (INIS)

    Jung, Jong-Min; Lee, Jechan; Choi, Dongho; Oh, Jeong-Ik; Lee, Sang-Ryong; Kim, Jae-Kon; Kwon, Eilhann E.

    2017-01-01

    Highlights: • Biodiesel production using renewable resources. • Thermally-induced non-catalytic transesterification. • Synthesis of fatty acid ethyl esters without conventional catalysts. • Using biochar as porous medium in the non-catalytic transesterification. - Abstract: This study put great emphasis on evaluating biochar as porous media for the thermally-induced non-catalytic transesterification reaction to synthesize fatty acid ethyl esters (FAEE) from coconut oil. Thermogravimetric analysis (TGA) of coconut oil experimentally justified that the bond dissociation of fatty acid from the backbone of triglycerides (TGs) could be achieved, which finding could be applied to the non-catalytic transesterification reaction. To use biochar as porous medium, the surficial morphology of maize residue biochar (MRB) was characterized, revealing that biochar possessed the wider pore size distribution ranging from meso- to macro-pores than SiO 2 . The highest yield of FAEE from non-catalytic transesterification of coconut oil in the presence of MRB was 87% at 380 °C. To further enhance the FAEE yield, further studies associated with the production of FAEE with biochar made from different biomasses and various pyrolytic conditions should be performed.

  10. Polymer-immobilized liquid membrane transport of palladium (II) from nitric acid media using some thia extractants as novel receptors

    International Nuclear Information System (INIS)

    Shukla, J.P.

    1996-01-01

    Carrier-facilitated co-transport of Pd (II) from dilute acidic nitrate solutions was examined across a polymer-immobilized liquid membrane (PILM) deploying S 6 -pentano-36 (S 6 -P-36), bis-(2-ethylhexyl) sulfoxide (BESO) and bis (2, 4, 4 trimethyl pentyl) monothio phosphinic acid (Cyanex 302) as the novel receptors. The study carried out to distinguish the driving force between H + and NO 3 - ion for the cation transport across PILM, indicated that NO 3 - ion not the H + ion seems to be the driving force for Pd (II) transport under the present conditions for both BESO-PILM and S 6 -P-36-PILM systems. Recovery of palladium from acidic process effluents generated in Purex reprocessing of spent fuels was successfully achieved. 39 refs., 8 figs., 7 tabs

  11. SOCIAL MEDIA

    Science.gov (United States)

    RESPONSIBILITY CENTCOM COALITION MEDIA SOCIAL MEDIA NEWS ARTICLES PRESS RELEASES IMAGERY VIDEOS TRANSCRIPTS VISITORS AND PERSONNEL FAMILY CENTER FAMILY READINESS CENTCOM WEBMAIL SOCIAL MEDIA SECURITY ACCOUNTABILITY HomeMEDIASOCIAL MEDIA Social Media CENTCOM'S ENGLISH SOCIAL MEDIA ACCOUNTS There are many U.S. military commands

  12. Oxidative leaching process with cupric ion in hydrochloric acid media for recovery of Pd and Rh from spent catalytic converters.

    Science.gov (United States)

    Nogueira, C A; Paiva, A P; Oliveira, P C; Costa, M C; da Costa, A M Rosa

    2014-08-15

    The recycling of platinum-group metals from wastes such as autocatalytic converters is getting growing attention due to the scarcity of these precious metals and the market pressure originated by increase of demand in current and emerging applications. Hydrometallurgical treatment of such wastes is an alternative way to the most usual pyrometallurgical processes based on smelter operations. This paper focuses on the development of a leaching process using cupric chloride as oxidising agent, in HCl media, for recovery of palladium and rhodium from a spent catalyst. The chloride media allows the adequate conditions for oxidising and solubilising the metals, as demonstrated by equilibrium calculations based on thermodynamic data. The experimental study of the leaching process revealed that Pd solubilisation is clearly easier than that of Rh. The factors temperature, time, and HCl and Cu(2+) concentrations were significant regarding Pd and Rh leaching, the latter requiring higher factor values to achieve the same results. Leaching yields of 95% Pd and 86% Rh were achieved under optimised conditions (T = 80 °C, t = 4h, [HCl] = 6M, [Cu(2+)] = 0.3M). Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Redox reactions of U(IV) and Pu(IV) with H2O2 generated in nitric acid media by power ultrasound

    International Nuclear Information System (INIS)

    Moisy, P.; Venault, L.; Madic, C.; Nikitenko, S.

    1998-01-01

    Power ultrasound causes water molecule dissociation on H o and OH o radicals due to high local temperatures and pressures generated in the cavitation threshold. In nitric acid media scavenging of OH o radicals with NO 3 - followed by NO 3 o radicals hydrolysis leads to H 2 O 2 formation. It was shown that H 2 O 2 generated under the effect of ultrasound with the frequency 20 kHz and intensity 1-3 Wcm -2 (Ar atmosphere) oxidizes U(IV) to U(VI) or reduces Pu(IV) to Pu(III) in 1-4 M HNO 3 in the presence of antinitrous reagents ( N 2 H 5 NO 3 or NH 2 SO 3 H). The effect of HNO 3 concentration and ultrasonic intensity on the kinetics of U(IV) oxidation and Pu(IV) reduction was studied. (author)

  14. The water soluble composite poly(vinylpyrrolidone–methylaniline: A new class of corrosion inhibitors of mild steel in hydrochloric acid media

    Directory of Open Access Journals (Sweden)

    R. Karthikaiselvi

    2017-02-01

    Full Text Available In recent years poly methyl aniline has been reported as one of the efficient corrosion inhibitors of mild steel in acidic media. In view of the major limitation of the insolubility of polymethyl aniline PMA, we propose to convert PMA into a water soluble composite using supporting polymer polyvinylpyrrolidone to get higher solubility and corrosion inhibition efficiency. The water soluble composite poly(vinylpyrrolidone-methyl aniline was synthesized by chemical oxidative polymerization and its inhibitive effect on mild steel in 1 M HCl has been investigated using weight loss and electrochemical techniques (potentiodynamic polarization studies and impedance spectroscopy. SEM and EDX analyses are carried out to establish a protective film formation on the metal surface.

  15. Noble metal-catalyzed homogeneous and heterogeneous processes in treating simulated nuclear waste media with formic acid

    International Nuclear Information System (INIS)

    King, R.B.; Bhattacharyya, N.K.; Smith, H.D.

    1995-09-01

    Simulants for the Hanford Waste Vitrification Plant feed containing the major non-radioactive components Al, Cd, Fe, Mn, Nd, Ni, Si, Zr, Na, CO 3 2 -, NO 3 -, and NO 2 - were used to study reactions of formic acid at 90 degrees C catalyzed by the noble metals Ru, Rh, and/or Pd found in significant quantities in uranium fission products. Such reactions were monitored using gas chromatography to analyze the CO 2 , H 2 , NO, and N 2 O in the gas phase and a microammonia electrode to analyze the NH 4 +/NH 3 in the liquid phase as a function of time. The following reactions have been studied in these systems since they are undesirable side reactions in nuclear waste processing: (1) Decomposition of formic acid to CO 2 + H 2 is undesirable because of the potential fire and explosion hazard of H 2 . Rhodium, which was introduced as soluble RhCl 3 -3H 2 O, was found to be the most active catalyst for H 2 generation from formic acid above ∼ 80 degrees C in the presence of nitrite ion. The H 2 production rate has an approximate pseudo first-order dependence on the Rh concentration, (2) Generation of NH 3 from the formic acid reduction of nitrate and/or nitrite is undesirable because of a possible explosion hazard from NH 4 NO 3 accumulation in a waste processing plant off-gas system. The Rh-catalyzed reduction of nitrogen-oxygen compounds to ammonia by formic acid was found to exhibit the following features: (a) Nitrate rather than nitrite is the principal source of NH 3 . (b) Ammonia production occurs at the expense of hydrogen production. (c) Supported rhodium metal catalysts are more active than rhodium in any other form, suggesting that ammonia production involves heterogeneous rather than homogeneous catalysis

  16. Studies on inhibition characteristics of corn steep liquor and black sulphite liquor on corrosion of mild steel in acid media

    Energy Technology Data Exchange (ETDEWEB)

    Deb, P C; Mukherjea, R N

    1968-06-01

    The purpose of this study was to economically reduce the attack by acid on the parent metal, during the process of removing mill scale by acid pickling. Two inhibitors, by-products of the starch industry and pulp industry, were studied due to their cheapness and availability in India. The inhibition efficiency of the corn steep liquor and black sulfite liquor was found to be below that of thiourea. For example, in 6.2% (w/w) H/sub 2/SO/sub 4/ (at 50/sup 0/C), an inhibition efficiency of 90.5% and 84.5% is reached for inhibitor concentrations of 10 g per liter in the case of corn steep liquor and black sulfite liquor, respectively, while a concentration of 0.25 g per liter of thiourea was required to reach an inhibition efficiency of 98.6%.

  17. Electrodeposition of ruthenium, rhodium and palladium from nitric acid and ionic liquid media: Recovery and surface morphology of the deposits

    Energy Technology Data Exchange (ETDEWEB)

    Jayakumar, M.; Venkatesan, K.A.; Sudha, R. [Fuel Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603102 (India); Srinivasan, T.G., E-mail: tgs@igcar.gov.com [Fuel Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603102 (India); Vasudeva Rao, P.R. [Fuel Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603102 (India)

    2011-07-15

    Research highlights: {yields} Platinum group metals are man-made noble metals. {yields} Electrochemical recovery of fission platinoids. {yields} Recovery from nitric acid medium. {yields} Recovery from ionic liquid medium. {yields} Platinoids with exotic surface morphologies. - Abstract: Electrodeposition is a promising technique for the recovery of platinum group metals with unique surface morphologies. The electrodeposition of palladium, ruthenium and rhodium from aqueous nitric acid, and non-aqueous 1-butyl-3-methylimidazolium chloride ionic liquid medium was studied at stainless steel electrode. The surface morphology and elemental composition of the resultant deposit were probed by scanning electron microscopy (SEM) and energy dispersive X-ray (EDS) analysis. Deposits with diverse surface morphologies and metal compositions were obtained by varying the composition of the electrolytic medium and applied potential. The results demonstrate the possibility of tailoring the morphologies of PGMs by controlling the composition and potential needed for electrodeposition.

  18. Effect of denaturants on the speciation of uranium(VI) complexes of malonic acid in micellar media

    International Nuclear Information System (INIS)

    Sailaja, B.B.V.; Kebede, Tesfahun; Nageswara Rao, G.; Prasada Rao, M.S.

    2001-01-01

    A computer assisted investigation has been made on the nature of complexes of uranium(VI) with malonic acid. The formation constants have been determined experimentally by monitoring hydrogen ion concentration. The distribution of the metal ion amongst the complexes formed with the above carboxylic acid has also been computed. The formation constants have been refined with the computer program, MINIQUAD75 using the primary alkalimetric data. The predominant complexes formed are UO 2 (H 2 C 3 O 4 ) 2 ) 2- , UO 2 (H 2 C 3 O 4 ) and UO 2 (H 2 C 3 O 4 )(H 2 C 3 O 4 H) - . The distribution pattern of different species varies with the relative concentrations of the metal ion and the ligand. The variation of stability with surfactant concentrations is found to be the cumulative effect of various factors like electrostatic interactions. dilution effect and competition for hydrogen ion associated with the nature of micelles. (author)

  19. Physicochemical properties and ecotoxicological effects of yttrium oxide nanoparticles in aquatic media: Role of low molecular weight natural organic acids

    International Nuclear Information System (INIS)

    Zhang, Fan; Wang, Zhuang; Wang, Se; Fang, Hao; Chen, Mindong; Xu, Defu; Tang, Lili; Wang, Degao

    2016-01-01

    Understanding how engineered nanoparticles (ENPs) interact with natural organic acids is important to ecological risk assessment of ENPs, but this interaction remains poorly studied. Here, we investigate the dispersion stability, ion release, and toxicity of yttrium oxide nanoparticles (nY_2O_3) suspensions after exposure to two low molecular weight natural organic acids (LOAs), namely benzoic acid and gallic acid. We find that in the presence of LOAs the nY_2O_3 suspensions become more stable with surface zeta potential more positive or negative, accompanied by small agglomerated size. LOA interaction with nY_2O_3 is shown to promote the release of dissolved yttrium from the nanoparticles, depending on the concentrations of LOAs. Toxic effects of the nY_2O_3 suspensions incubated with LOAs on Scenedesmus obliquus as a function of their mixture levels show three types of signs: stimulation, inhibition, and alleviation. The mechanism of the effects of LOAs on the nY_2O_3 toxicity may be mainly associated with the degree of agglomeration, particle-induced oxidative stress, and dissolved yttrium. Our results stressed the importance of LOA impacts on the fate and toxicity of ENPs in the aquatic environment. - Highlights: • LOAs significantly increased aqueous stability of nY2O3 in a dose-dependent manner. • The presence of LOAs promoted dissolution of nY2O3 in a dose-dependent manner. • Toxicity of nY2O3 with LOAs to Scenedesmus obliquus varied with mixture levels. • Stimulation, inhibition, and alleviation effects of nY2O3 with LOAs were observed. • Mechanism may be driven by agglomeration, oxidative stress, and dissolved yttrium. - LOAs elevate the dispersion stability of nano-Y_2O_3, promote the release of dissolved yttrium, and alter the algal toxicity of nano-Y_2O_3.

  20. Perfluorinated carboxylic and sulphonic acids in surface water media from the regions of Tibetan Plateau: Indirect evidence on photochemical degradation?

    Science.gov (United States)

    Yamazaki, Eriko; Falandysz, Jerzy; Taniyasu, Sachi; Hui, Ge; Jurkiewicz, Gabriela; Yamashita, Nobuyoshi; Yang, Yong-Liang; Lam, Paul K S

    2016-01-01

    Perfluorinated surfactants and repellents are synthetic substances that have found numerous industrial and customer applications. Due to their persistence, at least two groups of these substances-perfluorinated carboxylic acids (PFCAs) and perfluorinated sulfonic acids (PFSAs)-are diffused widely in the environment. It is hypothesized that the Tibetan Plateau, is one of few unique places on the Earth, due to its topography, specifically the vast space and high elevation above sea level, geographic location, climate, high solar radiation, lack of industry, little urbanization and general lack of significant direct sources of pollution. There it is believed possible to gain an insight into atmospheric fate (possible photochemical degradation of higher molecular mass and formation of lower molecular mass PFCAs and PFSAs) of PFASs under un-disturbed environmental conditions. Ultratrace analytical method for PFCAs and PFSAs and use of transportation and field blanks, laboratory blanks and isotopically labelled surrogates for recovery control has allowed the determination of nine perfluorinated carboxylic acids and six perfluorinated sulfonic acids at ultra-trace levels in water based samples from the alpine dimension regions of the Tibetan Plateau, the eastern slope of Minya Konka peak at the eastern edge of the Tibetan Plateau, and also from the city of Chengdu from the lowland of the Sichuan Province in China. The specific compositional pattern of PFCAs and PFSAs and low levels of pollution with those compounds were observed in the central region of the Tibetan Plateau and in the region adjacent to the peaks of Minya Konka in the Eastern Tibetan Plateau. The fingerprint of the compositional pattern of PFCAs and PFSAs in water samples in the central region of the Tibetan Plateau and in the alpine region adjacent to the peaks of Minya Konka in the Eastern Tibetan Plateau may be explained by the result of photochemical degradation with dealkylation of longer chain

  1. Study on complexation behaviour of uranium and thorium with amino acids at different temperatures in aqueous media

    International Nuclear Information System (INIS)

    Joshi, J.D.; Patel, M.R.; Patel, A.D.

    1992-01-01

    The complexation behaviour of uranium and thorium with important amino acids have been studied using Irving-Rossotti titration technique at 25deg, 35deg and 45degC in inert atmosphere of nitrogen and 0.1M ionic strength using NaClO 4 . The thermodynamic parameters ΔG, ΔH and ΔS have been calculated. Results indicate that thorium (IV) is forming more stable complexes than UO 2 2+ . (author). 3 refs., 2 tab

  2. Cacao pod husks as a source of low-methoxyl, highly acetylated pectins able to gel in acidic media.

    Science.gov (United States)

    Vriesmann, Lúcia Cristina; de Oliveira Petkowicz, Carmen Lúcia

    2017-08-01

    Cacao pod husks, the main by-product from cocoa production, have been investigated for pectin isolation. In the present study, the rheological properties of two low-methoxyl (LM) pectins isolated from cacao pod husks using different extraction conditions were evaluated. One pectin was obtained from optimized conditions employing aqueous nitric acid as an extractant, and the other one was extracted with boiling water. Pectin gels (0.99% galacturonic acid equivalent, w/w) were prepared at pH 2.5-3.0 in the presence of 60% sucrose (w/w) and subjected to rheological analysis. Dynamic oscillatory experiments at 25°C indicated that better gels were obtained at the lowest pH (2.5). Steady shear measurements revealed a shear-thinning behavior. The apparent viscosities of the samples increased as pH decreased. Gelation with calcium ions was not observed for either of the highly acetylated LM pectins analyzed. The rheological analysis results showed that despite their high acetyl content, LM pectins extracted by different methods from cacao pod husks were able to form gels at low pH under reduced water activity, suggesting a possible application in acidic products. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Synthesis of α- and #betta#- Nor - lapachones, its properties in acid media and its reaction with N-bromosuccinamide

    International Nuclear Information System (INIS)

    Pinto, A.V.; Pinto, M. do C.R.; Oliveira, C.G.T. de; Universidade Federal Fluminense, Niteroi

    1982-01-01

    α-nor-lapachone 4 and #betta#-nor-lapachone 5 are obtained from nor-lapachol 6 by cyclization reactions using hidrocloric acid in AcOH for the first one and sulfuric acid for the latter. The compounds 4 and 5 are obtained in high yields. On the acid conditions the isomers are interchangeable, this approach is described in scheme II. Chemical reactions have been done with the derivatives 4 and 5 with N-bromosuccinamide, in carbon tetracloride and benzene. These two isomers have shown different chemical behavior, and this difference could be related to the quinoidal structure. Thus, in Cl 4 , 4 reacted with one equivalent of NBS giving the expected product 8 (allyclic bromination). The #betta#-isomer 5 furnished the product II and required two equivalents of the NBS for complete consumption of the starting material. Using benzene, as solvent, it is observed an anomalous behaviour in the reaction. Schemes IV and VI show the proposed mechanisms for the reaction products according to the hitherto evidence. (Author) [pt

  4. Extraction of molybdenum by the di-n-butyl 2.2.N.hydroxyhexanamide (tri-n-butylacetohydroxamic acid) from aqueous acidic media

    International Nuclear Information System (INIS)

    Landesman, C.

    1991-11-01

    The design of a new industrial process for the production of the fission product 99 Mo, led to study of the extraction of 99 Mo(VI) by the tri-n-butylacetohydroxamic acid (TBAH). Due to the large affinity of TBAH for Mo(VI), the study was conducted with unusual experimental conditions : the concentrations of the extracting molecule and metallic ion were very low, typically CTBAH = 10 -5 M and CMo(VI) = 10 -8 M. The overall extraction system was described using a mathematical model quite simple, which, in particular, takes into account all the Mo(VI) species present in the aqueous phase. When the extractions were carried out from a perchloric acid medium, two different extraction mechanisms of Mo(VI) were identified : for C HC10 4 3 , the extraction of Mo(VI) corresponds to a cationic exchange, whereas for C HC10 4 > 3 mol/dm 3 , a neutral Mo(VI) compound is extracted. Moreover it was found that the extracting system Mo(VI)/TBAH is extremely sensitive to the temperature. It is thus possible to change the way of the transfer of Mo(VI) between the two phases, by control of the temperature of the mixture : the extraction is carried out at room temperature and the back-extraction at elevated temperature

  5. Extraction of zirconium(IV) and separation of 95Zr-95Nb from acidic thiocyanate media by LIX 54 and its mixtures with TBP

    International Nuclear Information System (INIS)

    Mishra, P.K.; Chakravortty, V.; Dash, K.C.; Das, N.R.; Bhattacharyya, S.N.

    1990-01-01

    Appreciable extraction of 95 Zr- 95 Nb by LIX 54 from aqueous HCl alone is not observed in the concentration range from 0.1 to 2 M HCl. Presence of thiocyanate ions results in appreciable extraction of this pair from such acid medium. Synergism has been observed in the extraction of zirconium(IV) by mixtures of LIX 54 and TBP from thiocyanate media, whereas there has been no appreciable synergism in case of niobium(V) under identical conditions. Slope analyses indicate the species extracted by pure TBP to be disolvate whereas for extraction by the mixtures of LIX 54 and TBP it is found to be monosolvate with respect to TBP. The extraction of both the metal ions have been found to depend on the concentration of acid as well as that of thiocyanate ions. Extraction increases with increase in percentage of either of the extractants. Effective separation of these congeneric pairs has been achieved by suitable choice of above system. Extraction is independent of aq. zirconium concentration up to 0.01 M above which it decreases. (orig.)

  6. Preparation of SBA-15-PAMAM as a Nano Adsorbent for Removal of Acid Red 266 from Aqueous Media: Batch Adsorption and Equilibrium Studies

    Directory of Open Access Journals (Sweden)

    Maryam Mirzaie

    2017-12-01

    Full Text Available The purpose of the present study was to increase the adsorption capacity of SBA-15 for acidic dyes. Ordered mesoporous silica SBA-15 was successfully synthesized and functionalized by polyamidoamine (PAMAM dendrimer to develop an efficient anionic dye adsorbent. The prepared materials were characterized by field emission scanning electron microscope (FE-SEM, Fourier transforms infrared spectroscope (FT-IR and N2 adsorption–desorption analysis. The study was concocted in the Science and Research Branch of Islamic Azad University of Tehran, Iran in 2016. The produced adsorbent (SBA-15-Den was applied for the removal of Acid Red 266 (AR266 from aqueous media. The effects of various operational parameters including solution pH, adsorbent dosage, contact time, and temperature on removal of AR266 using SBA-15-Den were investigated in batch adsorption mode. Within the optimum conditions, SBA-15-Den exhibited an excellent adsorptive capability of 1111.11 mg/g. Equilibrium data were best described by Langmuir model (R2 > 0.98 completely.

  7. A contribution to the study of thorium and neptunium (IV) complexes in acidic phosphoric media; Contribution a l`etude des complexes de thorium et de neptunium (IV) en milieux phosphoriques acides

    Energy Technology Data Exchange (ETDEWEB)

    Ghafar, M

    1995-11-30

    The thorium and neptunium (IV) phosphate complexes formation in acidic media has been investigated, essentially at the indicator`s level with {sup 227} Th, {sup 234} Th, {sup 235} Np and {sup 239} Np. Solvent extraction, a commonly used method for determining stability constants in solutions, was used with HDEHP in toluene. In order to get a better understanding of inorganic transparent gels formation in phosphoric aqueous solutions, the effect of the thorium concentration is also studied. Specific experimental conditions have been chosen in order to avoid the formation of chelate and hydrolysis in the aqueous solution. The equilibrium constants and stability constants are calculated, and the results are compared with literature. The results show that increasing the thorium concentration does not lead to polymer forms. refs., 42 figs., 19 tabs.

  8. Toward an Active and Stable Catalyst for Oxygen Evolution in Acidic Media: Ti-Stabilized MnO2

    DEFF Research Database (Denmark)

    Frydendal, Rasmus; Paoli, Elisa Antares; Chorkendorff, Ib

    2015-01-01

    Catalysts are required for the oxygen evolution reaction, which are abundant, active, and stable in acid. MnO2 is a promising candidate material for this purpose. However, it dissolves at high overpotentials. Using first-principles calculations, a strategy to mitigate this problem by decorating...... undercoordinated surface sites of MnO2 with a stable oxide is developed here. TiO2 stands out as the most promising of the different oxides in the simulations. This prediction is experimentally verified by testing sputter-deposited thin films of MnO2 and Ti-MnO2. A combination of electrochemical measurements...

  9. Porous media investigation before and after hydrochloric acid injection on a pre-salt carbonate coquinas sample.

    Science.gov (United States)

    Machado, A C; Teles, A P; Pepin, A; Bize-Forest, N; Lima, I; Lopes, R T

    2016-04-01

    Porous space characterization of carbonate rocks is an important aid in petroleum exploration from carbonate reservoir. In this study, X-ray microtomography technique was applied to evaluate total porosity of a coquina sample extracted from pre-salt reservoir, in Brazil, before and after acid injection. Two image processing program were used in order to assess performance. The results showed that microtomography has potential to compute porosity of coquina samples and provides information about rock porous network. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Multiwalled carbon nanotubes@octavinyl polyhedral oligomeric silsesquioxanes nanocomposite preparation via cross-linking reaction in acidic media

    Energy Technology Data Exchange (ETDEWEB)

    Somasekharan, Lakshmipriya; Thomas, Sabu [Mahatma Gandhi University, International and Interuniversity Centre for Nanoscience and Nanotechnology (India); Comoy, Corinne [Université de Lorraine, SRSMC, UMR 7565 (France); Sivasankarapillai, Anilkumar [NSS Hindu College (India); Kalarikkal, Nandakumar [Mahatma Gandhi University, International and Interuniversity Centre for Nanoscience and Nanotechnology (India); Lamouroux, Emmanuel, E-mail: Emmanuel.Lamouroux@univ-lorraine.fr [Université de Lorraine, SRSMC, UMR 7565 (France)

    2016-11-15

    Multiwalled carbon nanotubes have unique properties allowing their use in a wide range of applications—from microelectronics to biomedical and polymer fields. Nevertheless, a crucial aspect for their use resides in the ease of handling them during the process. Here, we report a facile route to prepare multiwalled carbon nanotubes@octavinyl polyhedral oligomeric silsesquioxanes (MWCNT@POSS) nanocomposite. The method involves the formation of a covalent bond between carboxylated MWCNTs and OV-POSS using acid-catalyzed electrophilic addition reaction. The resulting nanocomposite have been characterized by Fourier transform infrared spectroscopy (FTIR), powder X-Ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The results confirmed that the formation of MWCNT@POSS nanocomposite did not deteriorate MWCNT structure or morphology. Here, we used a 1:1 ratio of carboxylated MWCNTs and OV-POSS and the POSS content in the nanocomposite was 39.5 wt%.

  11. Kinetics of Corrosion Inhibition of Aluminum in Acidic Media by Water-Soluble Natural Polymeric Pectates as Anionic Polyelectrolyte Inhibitors.

    Science.gov (United States)

    Hassan, Refat M; Zaafarany, Ishaq A

    2013-06-17

    Corrosion inhibition of aluminum (Al) in hydrochloric acid by anionic polyeletrolyte pectates (PEC) as a water-soluble natural polymer polysaccharide has been studied using both gasometric and weight loss techniques. The results drawn from these two techniques are comparable and exhibit negligible differences. The inhibition efficiency was found to increase with increasing inhibitor concentration and decrease with increasing temperature. The inhibition action of PEC on Al metal surface was found to obey the Freundlich isotherm. Factors such as the concentration and geometrical structure of the inhibitor, concentration of the corrosive medium, and temperature affecting the corrosion rates were examined. The kinetic parameters were evaluated and a suitable corrosion mechanism consistent with the kinetic results is discussed in the paper.

  12. Kinetics of Corrosion Inhibition of Aluminum in Acidic Media by Water-Soluble Natural Polymeric Pectates as Anionic Polyelectrolyte Inhibitors

    Directory of Open Access Journals (Sweden)

    Refat M. Hassan

    2013-06-01

    Full Text Available Corrosion inhibition of aluminum (Al in hydrochloric acid by anionic polyeletrolyte pectates (PEC as a water-soluble natural polymer polysaccharide has been studied using both gasometric and weight loss techniques. The results drawn from these two techniques are comparable and exhibit negligible differences. The inhibition efficiency was found to increase with increasing inhibitor concentration and decrease with increasing temperature. The inhibition action of PEC on Al metal surface was found to obey the Freundlich isotherm. Factors such as the concentration and geometrical structure of the inhibitor, concentration of the corrosive medium, and temperature affecting the corrosion rates were examined. The kinetic parameters were evaluated and a suitable corrosion mechanism consistent with the kinetic results is discussed in the paper.

  13. Extraction and separation of molybdenum and vanadium from acidic and alkaline media using tertiary and quaternary amines

    International Nuclear Information System (INIS)

    Stas, J.; Dahdouh, A.; Rizkallah, I.

    2010-01-01

    phases (TDA and QA) with several stripping agents (H 2 SO 4 , (NH 4 ) 2 SO 4 , (NH 4 ) 2 CO 3 , Na 2 CO 3 , NaOH) has been studied and it was found that NaOH is the best stripping media for both extractants but with more difficulties for the quaternary amine methyl trioctyl ammonium chloride. Finally, it has been suggested two flowsheets for vanadium separation from molybdenum using TDA and QA. (author)

  14. Facts about Folic Acid

    Science.gov (United States)

    ... Information For… Media Policy Makers Facts About Folic Acid Language: English (US) Español (Spanish) Recommend on Facebook ... of the baby’s brain and spine. About folic acid Folic acid is a B vitamin. Our bodies ...

  15. Analysis of the formation of Ta2O5 passive films in acid media through mechanistic modeling

    International Nuclear Information System (INIS)

    Cabrera-Sierra, R.; Vazquez-Arenas, J.; Cardoso, S.; Luna-Sanchez, R.M.; Trejo, M.A.; Marin-Cruz, J.; Hallen, J.M.

    2011-01-01

    Electrochemical impedance spectroscopy (EIS) analyses are carried out to evaluate the passive features of tantalum oxide films (Ta 2 O 5 ) formed at different potentiostatic conditions (0.5, 1.0, 1.5 and 2.0 V vs SSE). A supporting electrolyte of 0.1 M H 2 SO 4 (pH 1) has been used to emulate acidic corrosive conditions for the growth of films with an n-type electronic character. A modification of the point defect model (PDM) accounting for the formation of molecular hydrogen (blistering damage) is used to fit the experimental EIS diagrams, and obtain the kinetic parameters that best describe the semiconductive behavior of the passive films. After this analysis, diffusivities in the order of 5.37 ± 1.6 x 10 -17 and 1.98 ± 1.4 x 10 -20 cm 2 s -1 were obtained for the oxygen (D VO·· ) and hydroxyl vacancies (D VOH· ), respectively. These findings show the capabilities of the EIS and the physicochemical modeling to account for the formation of valve-metal oxide films on a different range of conditions.

  16. Solvent extraction of Zn(II) from aqueous sulphate media by di(2-ethylhexyl) phosphoric acid in kerosene

    International Nuclear Information System (INIS)

    Begum, D.A.; Alauddin, M.; Rahman, M.S.

    2009-01-01

    The extraction equilibrium studies of Zn(II) from sulphate medium by di(2-ethylhexyl) phosphoric acid (D2EHPA, H/sub 2/A/sub 2/) in kerosene revealed that the distribution ratio (D) decreased with the increase of initial (Zn(A(II) in the aqueous phase and increased with the increase of equilibrium pH and extractant concentration. The equilibration is reached within 2 min. The species extracted into the organic phase is thought to be ZnA2, HA. The pH and extractant dependencies were about 2 and 1.67, respectively. The distribution ratio decreased with the increase in sulphate ion concentration in the aqueous phase. The extraction equilibrium reaction is suggested as Zn/sup 2+/ /sub aq/ +1.5 (H/sub 2/A/sub 2/)org - (ZnA/sub 2/, HA)org +2H/sup +/ /sub aq/. The extraction equilibrium constant (kex) for the above reaction was calculated to be 10-2.26. The extraction process was endothermic in nature having positive DH value of 16.27 kJ/mol. The loading of D2EHPA by Zn(II) is about 4.50 g of Zn(II) by 0.10 M D2EHPA. Possible reaction mechanism has been suggested based on distribution data, extractant concentration and equilibrium pH of the aqueous phase. (author)

  17. Experimental and quantum chemical studies on two triazole derivatives as corrosion inhibitors for mild steel in acid media

    Energy Technology Data Exchange (ETDEWEB)

    Li, W.; Tian, H.; Hou, B. [Key Laboratory of Corrosion Science, Shandong, Institute of Oceanology, Chinese Academy of Sciences, Qingdao (China); Hu, L.; Tao, Z. [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing (China)

    2011-11-15

    Two triazole derivatives [1-phenyl-2-(5-(1,2,4) triazol-1-ylmethyl-(1,3,4) oxadizaol-2-ylsulphanyl)-ethanone (PTOE) and 2-(4-tert-butyl-benzylsulphanyl)-5-(1,2,4) triazol-1-ylmethyl-(1,3,4) oxadiazole (TBTO)] were synthesized as new corrosion inhibitors for the corrosion of mild steel in 1 M hydrochloric acid solutions. The inhibiting efficiency of the different inhibitors was evaluated by means of weight loss and electrochemical techniques such as electrochemical impedance spectroscopy (EIS) and polarization curves. The electrochemical investigation results indicate that these compounds act as mixed-type inhibitors retarding the anodic and cathodic corrosion reactions and do not change the mechanism of either hydrogen evolution reaction or mild steel dissolution. The studied compounds followed the Langmuir adsorption isotherm, and the thermodynamic parameters were determined and discussed. The effect of molecular structure on the inhibition efficiency has been investigated with ab initio calculations. The electronic properties such as highest occupied molecular orbital (HOMO) energy level, lowest unoccupied molecular orbital (LUMO) energy level, dipole moment ({mu}) and molecular orbital densities were calculated. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Transport of ARS-labeled hydroxyapatite nanoparticles in saturated granular media is influenced by surface charge variability even in the presence of humic acid

    Science.gov (United States)

    Wang, Dengjun; Bradford, Scott A.; Harvey, Ronald W.; Hao, Xiuzhen; Zhou, Dongmei

    2012-01-01

    Hydroxyapatite nanoparticle (nHAP) is increasingly being used to remediate soils and water polluted by metals and radionuclides. The transport and retention of Alizarin red S (ARS)-labeled nHAP were investigated in water-saturated granular media. Experiments were carried out over a range of ionic strength (Ic, 0–50 mM NaCl) conditions in the presence of 10 mg L−1 humic acid. The transport of ARS-nHAP was found to decrease with increasing suspension Ic in part, because of enhanced aggregation and chemical heterogeneity. The retention profiles (RPs) of ARS-nHAP exhibited hyperexponential shapes (a decreasing rate of retention with increasing transport distance) for all test conditions, suggesting that some of the attachment was occurring under unfavorable conditions. Surface charge heterogeneities on the collector surfaces and especially within the ARS-nHAP population were contributing causes for the hyperexponential RPs. Consideration of the effect(s) of Ic in the presence of HA is needed to improve the efficacy of nHAP for scavenging metals and actinides in real soils and groundwater environments.

  19. A method for phenomenological and chemical kinetics study of autocatalytic reactive dissolution by optical microscopy. The case of uranium dioxide dissolution in nitric acid media

    Directory of Open Access Journals (Sweden)

    Marc Philippe

    2018-01-01

    Full Text Available Dissolution is a milestone of the head-end of hydrometallurgical processes, as the stabilization rates of the chemical elements determine the process performance and hold-up. This study aims at better understanding the chemical and physico-chemical phenomena of uranium dioxide dissolution reactions in nitric acid media in the Purex process, which separates the reusable materials and the final wastes of the spent nuclear fuels. It has been documented that the attack of sintering-manufactured uranium dioxide solids occurs through preferential attack sites, which leads to the development of cracks in the solids. Optical microscopy observations show that in some cases, the development of these cracks leads to the solid cleavage. It is shown here that the dissolution of the detached fragments is much slower than the process of the complete cleavage of the solid, and occurs with no disturbing phenomena, like gas bubbling. This fact has motivated the measurement of dissolution kinetics using optical microscopy and image processing. By further discriminating between external resistance and chemical reaction, the “true” chemical kinetics of the reaction have been measured, and the highly autocatalytic nature of the reaction confirmed. Based on these results, the constants of the chemical reactions kinetic laws have also been evaluated.

  20. A method for phenomenological and chemical kinetics study of autocatalytic reactive dissolution by optical microscopy. The case of uranium dioxide dissolution in nitric acid media

    Science.gov (United States)

    Marc, Philippe; Magnaldo, Alastair; Godard, Jérémy; Schaer, Éric

    2018-03-01

    Dissolution is a milestone of the head-end of hydrometallurgical processes, as the stabilization rates of the chemical elements determine the process performance and hold-up. This study aims at better understanding the chemical and physico-chemical phenomena of uranium dioxide dissolution reactions in nitric acid media in the Purex process, which separates the reusable materials and the final wastes of the spent nuclear fuels. It has been documented that the attack of sintering-manufactured uranium dioxide solids occurs through preferential attack sites, which leads to the development of cracks in the solids. Optical microscopy observations show that in some cases, the development of these cracks leads to the solid cleavage. It is shown here that the dissolution of the detached fragments is much slower than the process of the complete cleavage of the solid, and occurs with no disturbing phenomena, like gas bubbling. This fact has motivated the measurement of dissolution kinetics using optical microscopy and image processing. By further discriminating between external resistance and chemical reaction, the "true" chemical kinetics of the reaction have been measured, and the highly autocatalytic nature of the reaction confirmed. Based on these results, the constants of the chemical reactions kinetic laws have also been evaluated.

  1. Flow-injection chemiluminescence assay for ultra-trace determination of DNA using rhodamine B-Ce(IV)-DNA ternary system in sulfuric acid media

    International Nuclear Information System (INIS)

    Ma Yongjun; Zhou Min; Jin Xiaoyong; Zhang Ziyu; Teng Xiulan; Chen Hui

    2004-01-01

    A novel flow-injection chemiluminescence method for the determination of DNA at ultra-trace level has been established. In 0.8 M sulfuric acid media, the chemiluminescence of the rhodamine B-cerium (IV) or Ce(IV) system is enhanced by DNA, activated previously by imidazole-HCl buffer solution (pH 7.0). The enhanced intensity of chemiluminescence is in proportion to log DNA concentration 1.0x10 -8 to 0.1 μg ml -1 for herring sperm DNA and 2.0x10 -6 to 0.2 μg ml -1 for calf thymus DNA with 3σ detection limits of 8.3x10 -9 μg ml -1 for herring sperm DNA and 3.5x10 -7 μg ml -1 for calf thymus DNA, respectively. The relative standard deviation for 1.0x10 -4 μg ml -1 herring sperm DNA was 0.99% and 2.0x10 -3 μg ml -1 for calf thymus DNA was 1.1% (n=11). Using the optimized system, DNA contents in six synthetic samples has been determined with recoveries of 99.5-109.0%. The possible mechanism has also been studied in this paper

  2. Flow-injection chemiluminescence assay for ultra-trace determination of DNA using rhodamine B-Ce(IV)-DNA ternary system in sulfuric acid media

    Energy Technology Data Exchange (ETDEWEB)

    Ma Yongjun; Zhou Min; Jin Xiaoyong; Zhang Ziyu; Teng Xiulan; Chen Hui

    2004-01-09

    A novel flow-injection chemiluminescence method for the determination of DNA at ultra-trace level has been established. In 0.8 M sulfuric acid media, the chemiluminescence of the rhodamine B-cerium (IV) or Ce(IV) system is enhanced by DNA, activated previously by imidazole-HCl buffer solution (pH 7.0). The enhanced intensity of chemiluminescence is in proportion to log DNA concentration 1.0x10{sup -8} to 0.1 {mu}g ml{sup -1} for herring sperm DNA and 2.0x10{sup -6} to 0.2 {mu}g ml{sup -1} for calf thymus DNA with 3{sigma} detection limits of 8.3x10{sup -9} {mu}g ml{sup -1} for herring sperm DNA and 3.5x10{sup -7} {mu}g ml{sup -1} for calf thymus DNA, respectively. The relative standard deviation for 1.0x10{sup -4} {mu}g ml{sup -1} herring sperm DNA was 0.99% and 2.0x10{sup -3} {mu}g ml{sup -1} for calf thymus DNA was 1.1% (n=11). Using the optimized system, DNA contents in six synthetic samples has been determined with recoveries of 99.5-109.0%. The possible mechanism has also been studied in this paper.

  3. Media education.

    Science.gov (United States)

    Strasburger, Victor C

    2010-11-01

    The American Academy of Pediatrics recognizes that exposure to mass media (eg, television, movies, video and computer games, the Internet, music lyrics and videos, newspapers, magazines, books, advertising) presents health risks for children and adolescents but can provide benefits as well. Media education has the potential to reduce the harmful effects of media and accentuate the positive effects. By understanding and supporting media education, pediatricians can play an important role in reducing harmful effects of media on children and adolescents.

  4. Ethyl group as matrix modifier and inducer of ordered domains in hybrid xerogels synthesised in acidic media using ethyltriethoxysilane (ETEOS) and tetraethoxysilane (TEOS) as precursors

    International Nuclear Information System (INIS)

    Rios, Xabier; Moriones, Paula; Echeverría, Jesús C.; Luquin, Asunción; Laguna, Mariano; Garrido, Julián J.

    2013-01-01

    Hybrid silica xerogels favourably combine the properties of organic and inorganic components in one material; consequently these materials are useful for multiple applications. The versatility and mild synthetic conditions provided by the sol-gel process are ideal for the synthesis of hybrid materials. The specific aims of this study were to synthesise hybrid xerogels in acidic media using tetraethoxysilane (TEOS) and ethyltriethoxysilane (ETEOS) as silica precursors, and to assess the role of the ethyl group as a matrix modifier and inducer of ordered domains in xerogels. All xerogels were synthesised at pH 4.5, at 60 °C, with 1:4.75:5.5 TEOS:EtOH:H 2 O molar ratio. Gelation time exponentially increased with the ETEOS molar ratio. Incorporation of the ethyl groups into the structure of xerogels reduced cross-linking, increased the average siloxane bond length, and promoted the formation of ordered domains. As a result, a transition from Q n to T n signals detected in the 29 Si NMR spectra, the Si–O structural band in the FTIR spectra shifted to lower wavelength, and a new peak in the XRD pattern at 2θ < 10° appeared in the XRD patterns. Mass spectroscopy detected fragments with high numbers of silicon atoms and a polymeric distribution. - Graphical abstract: Display Omitted - Highlights: • Hybrid xerogels were synthesised for ETEOS/TEOS mixtures up to 80% ETEOS. • The gelification time exponentially increased with ETEOS content. • FTIR, XRD and MAS NMR demonstrated the presence of ethyl groups into xerogels. • For ETEOS contents ≤30%, ethyl group acted as matrix modifier. • For ETEOS contents ≥30%, ethyl groups induced the formation of ordered domains

  5. Media Komunitas dan Media Literacy

    Directory of Open Access Journals (Sweden)

    Pawito .

    2013-12-01

    Full Text Available Abstract:This essay deals with community media in relation to media literacy. After a short discussion on a number of community media characters is made the essay goes further with somewhat detail theoretical presumptions of the roles of media community with respect primarily to the development as Amartya Sen mentioned about. The author suggests that community media may play some significant roles in the development including (a disseminating information (from varieties of perspective, (b facilitating public discussion, (c helping to reach solutions of problems, (d encouraging participations, and (e encouraging the development of media literacy. Regarding the last point the author remarks that media community may have a dual-roles i.e facilitating community’s member in media participation and facilitating community’s member in media education.

  6. Locative media

    CERN Document Server

    Wilken, Rowan

    2014-01-01

    Not only is locative media one of the fastest growing areas in digital technology, but questions of location and location-awareness are increasingly central to our contemporary engagements with online and mobile media, and indeed media and culture generally. This volume is a comprehensive account of the various location-based technologies, services, applications, and cultures, as media, with an aim to identify, inventory, explore, and critique their cultural, economic, political, social, and policy dimensions internationally. In particular, the collection is organized around the perception that the growth of locative media gives rise to a number of crucial questions concerning the areas of culture, economy, and policy.

  7. Media Entrepreneurship

    DEFF Research Database (Denmark)

    Khajeheian, Datis

    2017-01-01

    Media Entrepreneurship has been an ambiguous, unclear and controversial concept and despite of growing academic efforts in the last decade, it is still a poorly defined subject. This paper is an effort to fill this gap by providing a comprehensive definition of media entrepreneurship. Firstly......, a literature review conducted and entrepreneurship, media, opportunity and innovation as building blocks of media entrepreneurship explained. Then by using of a mixed of bibliographic method and a Delphi method with multi-stage analysis process, a consensual definition of media entrepreneurship proposed...... entrepreneurship....

  8. Media Framing

    DEFF Research Database (Denmark)

    Pedersen, Rasmus T.

    2017-01-01

    The concept of media framing refers to the way in which the news media organize and provide meaning to a news story by emphasizing some parts of reality and disregarding other parts. These patterns of emphasis and exclusion in news coverage create frames that can have considerable effects on news...... consumers’ perceptions and attitudes regarding the given issue or event. This entry briefly elaborates on the concept of media framing, presents key types of media frames, and introduces the research on media framing effects....

  9. Sensitive Media

    Directory of Open Access Journals (Sweden)

    Malinowska Anna

    2017-12-01

    Full Text Available The paper engages with what we refer to as “sensitive media,” a concept associated with developments in the overall media environment, our relationships with media devices, and the quality of the media themselves. Those developments point to the increasing emotionality of the media world and its infrastructures. Mapping the trajectories of technological development and impact that the newer media exert on human condition, our analysis touches upon various forms of emergent affect, emotion, and feeling in order to trace the histories and motivations of the sensitization of “the media things” as well as the redefinition of our affective and emotional experiences through technologies that themselves “feel.”

  10. Media Ecology

    Directory of Open Access Journals (Sweden)

    Marina Ašković

    2015-05-01

    Full Text Available Does the trend in which electronic media are gradually becoming extension of human body have to move towards full enslavement of a human and his personality, or the same human will unpredictably, with the aid of his personal media literacy, exit the whirls of media and technological censorships? Personality crisis is closely related to the crisis of language no matter how contradicted to global ideology of transnational transhumanism it may seem. Considering the fact that recent media presentations of the world are based on commercialization of environmentalism, philosophical and aesthetic thought appears as an important subject of ecology. As media mediates, the scenery of civilized living increasingly becomes more appealing even though it derives from commercial and political background. Consequently, the future of humanity depends by large on the philosophy of media. Media have to truly ecologise returning the humanum to its essence making it into the extension of the natural world.

  11. Synergistic solvent extraction investigation of Am (III), Eu (III), Zn(II), and Cs(I), using 2-heptyl-2-methyl-nonanoic acid mixed with different organophosphorus compounds from nitrate media. Vol. 3

    International Nuclear Information System (INIS)

    El-Naggar, H.A.; Ramadan, A.; Abdel-Fattah, A.

    1996-01-01

    Extraction studies for investigating the effect of mixing 2-heptyl-2-methyl nonanoic acid (HA) with a number of organophosphorus compounds; namely tributyl phosphate (TBP), terphenyl phosphate oxide (TPPO); tri octyl phosphine oxide (TOPO) or bis-2-(ethyl hexyl) phosphoric acid (HDEHP) in benzene on the extraction of trace elements Am(III), Eu(III), Zn(II), and Cs(I) from nitrate media of ionic strength, I=0.1 M were carried out. The effect of adding different organophosphorus compounds to HA was tested to account for the presence or absence of the phenomenon of synergism. It was found that TBP, TPPO, and TOPO causing some antagonistic effects for the elements studied. Extraction enhancement was only observed with bis- (2-ethyl-hexyl) -phosphoric acid (HDEHP) for all the elements investigated. The extraction mechanisms as well as the thermodynamic parameters for the mixed extracted species are discussed. 19 figs

  12. Synergistic solvent extraction investigation of Am (III), Eu (III), Zn(II), and Cs(I), using 2-heptyl-2-methyl-nonanoic acid mixed with different organophosphorus compounds from nitrate media. Vol. 3

    Energy Technology Data Exchange (ETDEWEB)

    El-Naggar, H A; Ramadan, A; Abdel-Fattah, A [Nuclear Chemistry Department, Hot Laboratories Center, Atomic Energy Authority, Cairo (Egypt)

    1996-03-01

    Extraction studies for investigating the effect of mixing 2-heptyl-2-methyl nonanoic acid (HA) with a number of organophosphorus compounds; namely tributyl phosphate (TBP), terphenyl phosphate oxide (TPPO); tri octyl phosphine oxide (TOPO) or bis-2-(ethyl hexyl) phosphoric acid (HDEHP) in benzene on the extraction of trace elements Am(III), Eu(III), Zn(II), and Cs(I) from nitrate media of ionic strength, I=0.1 M were carried out. The effect of adding different organophosphorus compounds to HA was tested to account for the presence or absence of the phenomenon of synergism. It was found that TBP, TPPO, and TOPO causing some antagonistic effects for the elements studied. Extraction enhancement was only observed with bis- (2-ethyl-hexyl) -phosphoric acid (HDEHP) for all the elements investigated. The extraction mechanisms as well as the thermodynamic parameters for the mixed extracted species are discussed. 19 figs.

  13. Media Flow

    DEFF Research Database (Denmark)

    Kabel, Lars

    2016-01-01

    News and other kinds of journalistic stories, 16-17 hours a day, all year round, on all platforms, also the moderated social media. The key research thesis behind this article is that the continuous and speedy stream of news stories and media content now is becoming the centre of the production...... processes and the value creation in converged multimedia newsrooms. The article identify new methods and discuss editorial challenges in handling media flow....

  14. Effects of Indole-Butyric Acid Doses, Different Rooting Media and Cutting Thicknesses on Rooting Ratios and Root Qualities of 41B, 5 BB and 420A American Grapevine Rootstocks

    OpenAIRE

    DOĞAN, Adnan; UYAK, Cüneyt; KAZANKAYA, Ahmet

    2016-01-01

    The present study was conducted to investigate the effects of different rooting media [perlite, perlite+sand (1:1), perlite+sand+soil (1:1:1)], different indole butyric acid (IBA) doses (control, 1000, 2000, 3000 and 4000 ppm) and different cutting thicknesses [thin (4-7 mm), medium (8-10 mm) and thick (10-12 mm)] on rooting and root qualities of 41B, 5BB and 420A American grapevine rootstocks adapted to Van region of Turkey. Within the scope of the study, rooting ratios (%), number of roots,...

  15. Instructional Media

    African Journals Online (AJOL)

    This can be summed up in a few words: Students can learn a great deal from any of the media. Under most of the conditions tested, they could learn as much as from ... Beyond physical conditions (deafness) there is little reason to expect a differential media. Scientia Militaria, South African Journal of Military Studies, Vol 13 ...

  16. Mixed Media

    Science.gov (United States)

    Peterson, Erin

    2010-01-01

    While institutions do not often have a hook as compelling as an eagerly awaited movie, great content is critical for media relations success--and coupling it with the right distribution channel can ensure the story finds the right audience. Even better, retooling it for several media platforms can extend the life and reach of a story. The changes…

  17. Media darling

    CERN Multimedia

    Chalmers, Matthew

    2008-01-01

    He is the media-friendly face of particle physics, appearing on countless TV and radio shows in the run-up to the opening of CERN's Large Hadron Collider. Matthew Chalmers discovers how Brian Cox finds the time to be both a physicist and a media personality. (2 pages)

  18. Media Art

    DEFF Research Database (Denmark)

    Ekman, Ulrik

    2015-01-01

    environments, experience time, and develop identities individually and socially. Interviews with working media artists lend further perspectives on these cultural transformations. Drawing on cultural theory, new media art studies, human-computer interaction theory, and software studies, this cutting-edge book...... critically unpacks the complex ubiquity-effects confronting us every day....

  19. Online monitoring of electrocatalytic reactions of alcohols at platinum and gold electrodes in acidic, neutral and alkaline media by capillary electrophoresis with contactless conductivity detection (EC-CE-C4 D).

    Science.gov (United States)

    Ferreira Santos, Mauro Sérgio; Silva Lopes, Fernando; Gutz, Ivano Gebhardt Rolf

    2017-11-01

    An EC-CE-C 4 D flow system was applied to the investigation of electrocatalytic processes by monitoring carboxylic acids formed during the electro-oxidation at various potentials of primary alcohols (mixture of 1 mmol/L of ethanol, n-propanol, n-butanol and n-pentanol) in acidic, neutral and alkaline media. The electro-oxidation was carried out on gold and platinum disk electrodes (3 mm of diameter) in a thin-layer electrochemical flow cell. Products were sampled 50 μm apart from the electrode directly into the capillary. All the generated carboxylates were determined in near real time (less than 2 min) by CE-C 4 D in counter-flow mode, with Tris/HCl buffer solution (pH 8.6) as BGE. Long sequences of 5-min experiments were run automatically, exploring the applied potential, electrolysis time and solution composition. Electro-oxidation at 1.5 V (versus Ag/AgCl quasi-reference) during 50 s in acidic medium was found appropriate for both Pt and Au electrodes when the determination of alcohols after derivatization is intended. A noteworthy selectivity effect was observed on the Au electrode. The signal corresponding to pentanoate is similar on both electrodes while the signal of ethanoate (acetate) is four times larger on gold than on platinum. The carboxylate signals were lower in alkaline medium (below the determination limit on Pt) than in acidic and neutral media. On gold, the formation of carboxylates was anticipated (0.85 V in alkaline medium versus 1.40 V in neutral medium). The automatic online monitoring of electrochemical processes by EC-CE-C 4 D holds great potential to investigate ionic/ionizable intermediates/products of new electrocatalysts and/or alternative fuels. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Transport of ARS-labeled hydroxyapatite nanoparticles in saturated granular media is influenced by surface charge variability even in the presence of humic acid

    Science.gov (United States)

    Hydroxyapatite nanoparticles (nHAP) are increasingly being used to remediate soils and water polluted by metals and radionuclides. The transport and retention of Alizarin red S (ARS)-labeled nHAP in water-saturated granular media were investigated. Experiments were conducted over a range of ionic ...

  1. Media violence.

    Science.gov (United States)

    Cantor, J

    2000-08-01

    Research on the effects of media violence is not well understood by the general public. Despite this fact, there is an overwhelming consensus in the scientific literature about the unhealthy effects of media violence. Meta-analyses show that media-violence viewing consistently is associated with higher levels of antisocial behavior, ranging from the trivial (imitative violence directed against toys) to the serious (criminal violence), with many consequential outcomes in between (acceptance of violence as a solution to problems, increased feelings of hostility, and the apparent delivery of painful stimulation to another person). Desensitization is another well-documented effect of viewing violence, which is observable in reduced arousal and emotional disturbance while witnessing violence, the reduced tendency to intervene in a fight, and less sympathy for the victims of violence. Although there is evidence that youth who are already violent are more likely to seek out violent entertainment, there is strong evidence that the relationship between violence viewing and antisocial behavior is bidirectional. There is growing evidence that media violence also engenders intense fear in children which often lasts days, months, and even years. The media's potential role in solutions to these problems is only beginning to be explored, in investigations examining the uses and effects of movie ratings, television ratings, and the V-chip, and the effects of media literacy programs and public education efforts. Future research should explore important individual differences in responses to media violence and effective ways to intervene in the negative effects.

  2. From Augmentation Media to Meme Media.

    Science.gov (United States)

    Tanaka, Yuzuru

    Computers as meta media are now evolving from augmentation media vehicles to meme media vehicles. While an augmentation media system provides a seamlessly integrated environment of various tools and documents, meme media system provides further functions to edit and distribute tools and documents. Documents and tools on meme media can easily…

  3. Redox potential monitoring as a method to control unwanted noble metal-catalyzed hydrogen generation from formic acid treatment of simulated nuclear waste media

    International Nuclear Information System (INIS)

    King, R.B.; Bhattacharyya, N.K.

    1998-01-01

    Simulants for the Hanford Waste Vitrification Plant feed containing the major nonradioactive components Al, Cd, Fe, Mn, Nd, Ni, Si, Zr, Na, CO 3 2- , NO 3 - , and NO 2 - were used to study redox potential changes in reactions of formic acid at 90 C catalyzed by the noble metals Ru, Rh, and/or Pd found in significant quantities in uranium fission products. Such reactions were monitored using gas chromatography to analyze the CO 2 , H 2 , NO, and N 2 O in the gas phase and a redox electrode to follow redox potential changes as a function of time. In the initial phase of formic acid addition to nitrite-containing feed simulants, the redox potential of the reaction mixture rises typically to +400 mV relative to the Al/AgCl electrode because of the generation of the moderately strongly oxidizing nitrous acid. No H 2 production occurs at this stage of the reaction as long as free nitrous acid is present. After all of the nitrous acid has been destroyed by reduction to N 2 O and NO and disproportionation to NO/NO 3 - , the redox potential of the reaction mixture becomes more negative than the Ag/AgCl electrode. The experiments outlined in this paper suggest the feasibility of controlling the production of H 2 by limiting the amount of formic acid used and monitoring the redox potential during formic acid treatment

  4. On the relationship between corrosion inhibiting effect and molecular structure of 2,5-bis(n-pyridyl)-1,3,4-thiadiazole derivatives in acidic media: Ac impedance and DFT studies

    Energy Technology Data Exchange (ETDEWEB)

    Bentiss, F., E-mail: fbentiss@enscl.f [Laboratoire de Chimie de Coordination et d' Analytique (LCCA), Faculte des Sciences, Universite Chouaib Doukkali, B.P. 20, M-24000 El Jadida (Morocco); Mernari, B. [Laboratoire de Chimie de Coordination et d' Analytique (LCCA), Faculte des Sciences, Universite Chouaib Doukkali, B.P. 20, M-24000 El Jadida (Morocco); Traisnel, M. [Unite Materiaux et Transformations (UMET), Ingenierie des Systemes Polymeres, CNRS UMR 8207, ENSCL, B.P. 90108, F-59652 Villeneuve d' Ascq Cedex (France); Vezin, H. [Laboratoire de Spectrochimie Infrarouge et Raman (LASIR), UMR-CNRS 8516, Universite des Sciences et Technologies de Lille, Batiment C5, F-59655 Villeneuve d' Ascq Cedex (France); Lagrenee, M., E-mail: michel.lagrenee@ensc-lille.f [Unite de Catalyse et de Chimie du Solide (UCCS), UMR-CNRS 8181, ENSCL, B.P. 90108, F-59652 Villeneuve d' Ascq Cedex (France)

    2011-01-15

    Research highlights: {yields}2,5-Bis(n-pyridyl)-1,3,4-thiadiazoles (n-PTH) act as good inhibitors for the mild steel in acidic media. {yields}The inhibiting protection depends on the position of the nitrogen on the pyridinium substituent according to order 3-PTH > 2-PTH > 4-PTH. {yields}The adsorption of n-PTH is found to follow the Langmuir's adsorption isotherm. {yields}Data obtained from quantum chemical calculations using DFT method were correlated to the experimentally obtained inhibition efficiencies. - Abstract: The inhibition properties of 2,5-bis(n-pyridyl)-1,3,4-thiadiazoles (n-PTH) on corrosion of mild steel in different acidic media (1 M HCl, 0.5 M H{sub 2}SO{sub 4} and 1 M HClO{sub 4}) were analyzed by electrochemical impedance spectroscopy (EIS). The n-PTH derivatives exhibit good inhibition properties in different acidic solutions and the calculated values of {Delta}G{sub ads}{sup 0} revealed that the adsorption mechanism of n-PTH on steel surface is mainly due to chemisorption. While in 1 M HClO{sub 4}, both 2-PTH and 4-PTH isomers stimulate the corrosion process especially at low concentrations. Quantum chemical calculations using the density functional theory (DFT) were performed on n-PTH derivatives to determine the relationship between molecular structure and their inhibition efficiencies. The results of the quantum chemical calculations and experimental inhibition efficiency were subjected to correlation analysis and indicate that the inhibition effects of n-PTH may be explained in terms of electronic properties.

  5. RESEARCH REGARDING THE DYNAMICS OF SOME BIOCHEMICAL MARKERS OF OXIDATIVE STRESS AT MONILINIA LAXA (ADRH. & RUHL. HONEY CULTIVATED ON DIFFERENT AMINO ACIDS ENRICHED MEDIA

    Directory of Open Access Journals (Sweden)

    Elena Ciornea

    2010-09-01

    Full Text Available Antioxidants that make up the defense for Ascomycetes still arouses a major interest because of their hypothetical role as virulence and aggression factors and also as the enzymes that play a key role in cellular defense against ROS produced during microbial metabolic activity. A study of catalase and peroxidase activity dynamics of the species Monilinia laxa (Aderh & Ruhl. Honey cultivated in vitro on medium supplemented with different amino acids was conducted in order to know the biology of the fungi responsible for the appearance of brown rot at various species of stone fruits. We used for this purpose the Leonian medium (in the formula changed by Bonnar, in each variant being added 0, 125 mg of the following amino acids: alanine, glutamic acid, asparagine, aspartic acid, cystine, cysteine, phenylalanine, histidine, valine, lysine, serine, methionine and leucine. We also used a control variant, without amino acids, in final resulting 14 working versions. To determine the catalase activity Sinha method was used, to monitor the peroxidase activity we used Möller method and the experimental measurements carried out at two intervals, were made both of fungus mycelium and culture fluid. We found notable differences in the activity of two enzymes, microbial culture induced both by the age of the culture medium and the type of amino acid introduced in it.

  6. Co-extraction and co-stripping of U(VI) and Pu(IV) using tri-iso-amyl phosphate and tri-n-butyl phosphate in n-dodecane from nitric acid media under high loading conditions

    Energy Technology Data Exchange (ETDEWEB)

    Sreenivasulu, Balija; Suresh, Ammath; Sivaraman, Nagarajan; Rao, P.R. Vasudeva [Indira Gandhi Centre for Atomic Research, Kalpakkam (India). Chemistry Group

    2016-08-01

    The extraction of Pu(IV) using 1.1 M solution of tri-iso-amyl phosphate (TiAP)/n-dodecane (DD) from plutonium nitrate solutions in nitric acid media was examined as a function of equilibrium aqueous phase metal ion concentration and equilibrium aqueous phase acidity at 303 K. The nitric acid concentration in the organic phase was measured as a function of equilibrium organic phase plutonium concentration. The co-extraction of U(VI) and Pu(IV) was studied using 1.1 M TiAP/DD system as a function of their equilibrium aqueous phase metal ion concentration and compared with 1.1 M tri-n-butyl phosphate (TBP)/n-DD system under identical conditions. Co-extraction and co-stripping of U(VI) and Pu(IV) were studied using 1.1 M TiAP/DD and 1.1 M TBP/DD systems in cross current mode to evaluate the number of stages required for the extraction and stripping of heavy metal ions (uranium and plutonium). The extraction and stripping efficiencies were calculated for both the systems. The saturation limit of the organic phase was also established in these studies.

  7. Co-extraction and co-stripping of U(VI) and Pu(IV) using tri-iso-amyl phosphate and tri-n-butyl phosphate in n-dodecane from nitric acid media under high loading conditions

    International Nuclear Information System (INIS)

    Sreenivasulu, Balija; Suresh, Ammath; Sivaraman, Nagarajan; Rao, P.R. Vasudeva

    2016-01-01

    The extraction of Pu(IV) using 1.1 M solution of tri-iso-amyl phosphate (TiAP)/n-dodecane (DD) from plutonium nitrate solutions in nitric acid media was examined as a function of equilibrium aqueous phase metal ion concentration and equilibrium aqueous phase acidity at 303 K. The nitric acid concentration in the organic phase was measured as a function of equilibrium organic phase plutonium concentration. The co-extraction of U(VI) and Pu(IV) was studied using 1.1 M TiAP/DD system as a function of their equilibrium aqueous phase metal ion concentration and compared with 1.1 M tri-n-butyl phosphate (TBP)/n-DD system under identical conditions. Co-extraction and co-stripping of U(VI) and Pu(IV) were studied using 1.1 M TiAP/DD and 1.1 M TBP/DD systems in cross current mode to evaluate the number of stages required for the extraction and stripping of heavy metal ions (uranium and plutonium). The extraction and stripping efficiencies were calculated for both the systems. The saturation limit of the organic phase was also established in these studies.

  8. Determination of total arsenic and arsenic(III) in phosphate fertilizers by hydride generation atomic absorption spectrometry after ultrasound-assisted extraction based on a control acid media.

    Science.gov (United States)

    Rezende, Helen Cristine; Coelho, Nivia Maria Melo

    2014-01-01

    An ultrasound-assisted extraction procedure was developed for determination of inorganic arsenic (As) in phosphate fertilizer by hydride generation atomic absorption spectrometry. The variables that affect the hydride generation step were optimized, including the reducer, acid, sample flow rate, and concentrations of the acid and reducer. The determination of As(lll) was performed through the simple control of solution pH with a 0.5 M citric acid-sodium citrate buffer solution at pH 4.5, and total As was determined after a pre-reduction reaction with 1.0% (w/v) thiourea. Ultrasound-assisted acid extraction was performed, and the parameters sonication time and acid and Triton X-114 concentrations were optimized using a 23 factorial design and central composite design. LODs for As(lll) and total As were 0.029 and 0.022 microg/L, respectively. The accuracy of the method was confirmed with certified reference materials. The method was successfully applied in the determination of inorganic As in phosphate fertilizer samples.

  9. Media Training

    CERN Multimedia

    CERN. Geneva

    2009-01-01

    With the LHC starting up soon, the world's media are again turning their attention to CERN. We're all likely to be called upon to explain what is happening at CERN to media, friends and neighbours. The seminar will be given by BBC television news journalists Liz Pike and Nadia Marchant, and will deal with the kind of questions we're likely to be confronted with through the restart period. The training is open for everybody. Make sure you arrive early enough to get a seat - there are only 200 seats in the Globe. The session will also be webcast: http://webcast.cern.ch/

  10. Standard and applied material testing methods of austenitic CrNi stainless steels in different nitric acid media - procedures and results

    International Nuclear Information System (INIS)

    Leistikow, S.; Kraft, R.; Schanz, G.

    1989-07-01

    Extended ASTM Standard Huey Testing has been performed in at 120 0 C boiling 14.4 molar (65%) nitric acid during 15 periods (15x48 = 720 h duration) for quality control of numerous commercial nitric acid resistant austenitic CrNi steels. It was shown how sensitively the chosen testing conditions could differentiate between CrNi steels of the same nominal composition as specified for DIN W.Nr. 1.4306 (AISI Type 304 L), but with varying residual element contents. Within an attempt to differentiate within this group of steels by application of electrochemical methods, potentiostatic tests at 1250 mV in nitric acid of equal concentration and temperature were able to detect remarkable differences in corrosion behaviour already after one hour. Another approach, more typical for the electrochemical potentials during materials application in reprocessing plants of nuclear fuel, gave preference to long-term immersion tests, which were performed in nitric acid of lower concentration and temperature. Reference tests in pure 7 molar, 90 0 C nitric acid could only reveal by surface attack small differences in steel quality by exposures of 720 h duration. To shorten the test time by an increase of the redox potential chromium (VI) ions were added to the nitric acid. In a solution of 0,5 g Gr (VI)/l at 90 0 C remarkable differences in corrosion behavior of the steels - similar to the Huey test results - became measurable by means of gravimetry and metallography already during a short-term exposure of 24-71 h. (orig./MM) [de

  11. Kinetics and mechanism of OsOsub(4) catalyzed oxidation of chalcones by Cesub(4) in aqueous acetic sulfuric acid media

    International Nuclear Information System (INIS)

    Srinivasulu, P.V.; Adinarayana, M.; Sethuram, B.; Rao, T.N.

    1985-01-01

    Kinetics of OsOsub(4) catalyzed oxidation of chalcones by Cesup(4+) was studied in aqueous acetic-sulfuric acid medium in the temperature range 313 to 338 K. The order in oxidant is zero while the order with respect to substrate and catalyst are each fractional. The rate of the reaction decreased with increase in percentage of acetic acid while [Hsup(+)] had practically no effect on the rate. The rates of various substituted chalcones are given. A mechanism in which formation of a cyclic ester between chalcone and OsOsub(4) in a fast step followed by its decomposition in a rate-determining step is envisaged. (author)

  12. Social Media Sites

    Science.gov (United States)

    Media Sites Site Registration Contact Us Search AF.mil: Home > AF Sites > Social Media Sites Social Media Welcome to the Air Force social media directory! The directory is a one-stop shop of official Air Force social media pages across various social media sites. Social media is all about

  13. Determination of vanadium in stainless steel and Ni-base alloys by NBPHA spectrophotometric method combined with chloroform extraction separation in media of sulfuric-hydrofluoric acid

    International Nuclear Information System (INIS)

    Sakai, Fumiaki; Ohuchi, Yoshifusa; Ochiai, Kenichi; Motoyama, Sigeji; Tsutsumi, Ken-ichi

    1975-01-01

    A new method of rapid vanadium analysis was proposed. In this method, vanadium is directly extracted and determined from sample solutions in sulfuric-hydrofluoric acid. The interference of the coexisting elements can be ignored in this method. Take one gram of sample into a 200 ml beaker, and add 30 ml of aqua regia. Then heat and dissolve it, and add 14 ml of sulfuric acid (1+1) and 5 ml of phosphoric acid. After cooling, dissolve the salts with a small amount of water. Thereafter, transfer it with use of water into a polyethylene separatory funnel, add 10 ml of 46% hydrofluoric acid, and dilute to 50 ml. Then, add 4 ml iron (II) ammonium sulfate solution (10%) and mix it thoroughly. Allow to stand for two or three minutes, add 10 ml of 45% ammonium persulfate solution and mix it thoroughly again. Allow to stand for about five minutes. Then, add exactly 20 ml of BPHA-chloroform solution (0.1%) and shake and mix it vigorously for two minutes. After a while, transfer the chloroform complex into a 10 mm cell through a piece of absorbent cotton. Then, determine vanadium by measuring the absorbance at the wave length of 530 nm against a chloroform reference. This method can be applicable to the analysis of vanadium in other metals and alloys than stainless steel and Ni-base alloys. (Iwakiri, K.)

  14. Efficient and convenient oxidation of benzyl halides to carbonyl compounds with sodium nitrate and acetic acid by phase transfer catalysis in aqueous media

    Directory of Open Access Journals (Sweden)

    Yu Lin Hu

    2010-08-01

    Full Text Available A variety of benzyl halides were converted to the corresponding aldehydes/ketones in good to high yields by phase transfer catalysis combined with sodium nitrate and acetic acid at reflux. As a result, a simple and high yield procedure has been developed.

  15. Contrast media

    International Nuclear Information System (INIS)

    Decazes, Ph.

    2004-01-01

    The Guerbet firm, which holds 69% of the capital on the contrast media for medical imagery, could sale about 20% of this capital in order to accelerate its development in the United States, one of its next market with the Japan. (O.M.)

  16. Otitis media

    NARCIS (Netherlands)

    Rovers, MM; Schilder, AGM; Zielhuis, GA; Rosenfeld, RM

    2004-01-01

    Otitis media (OM) continues to be one of the most common childhood infections and is a major cause of morbidity in children. The pathogenesis of OM is multifactorial, involving the adaptive and native immune system, Eustachian-tube dysfunction, viral and bacterial load, and genetic and environmental

  17. Social Media

    Science.gov (United States)

    2010-05-01

    Digital Marketing and Ecommerce Professionals. 29 January 2010. 20 May 2010. <http://econsultancy.com/blog/5324-20+-mind-blowing-social- media...Statistics Revisited.” Econsultancy | Community of Digital Marketing and Ecommerce Professionals. 29 Jan. 2010. 20 May 2010. <http://econsultancy.com/blog

  18. Streaming Media

    Science.gov (United States)

    Pulley, John

    2009-01-01

    At a time when the evolutionary pace of new media resembles the real-time mutation of certain microorganisms, the age-old question of how best to connect with constituents can seem impossibly complex--even for an elite institution plugged into the motherboard of Silicon Valley. Identifying the most effective vehicle for reaching a particular…

  19. Micro-ribonucleic acids and extracellular vesicles repertoire in the spent culture media is altered in women undergoing In Vitro Fertilization.

    Science.gov (United States)

    Abu-Halima, Masood; Häusler, Sebastian; Backes, Christina; Fehlmann, Tobias; Staib, Claudia; Nestel, Sigrun; Nazarenko, Irina; Meese, Eckart; Keller, Andreas

    2017-10-19

    MicroRNAs (miRNAs) are class of small RNA molecules with major impact on gene regulation. We analyzed the potential of miRNAs secreted from pre-implantation embryos into the embryonic culture media as biomarkers to predict successful pregnancy. Using microarray analysis, we profiled the miRNome of the 56 spent culture media (SCM) after embryos transfer and found a total of 621 miRNAs in the SCM. On average, we detected 163 miRNAs in SCM of samples with failed pregnancies, but only 149 SCM miRNAs of embryos leading to pregnancies. MiR-634 predicted an embryo transfer leading to a positive pregnancy with an accuracy of 71% and a sensitivity of 85%. Among the 621 miRNAs, 102 (16.4%) showed a differential expression between positive and negative outcome of pregnancy with miR-29c-3p as the most significantly differentially expressed miRNA. The number of extracellular vehicles was lower in SCM with positive outcomes (3.8 × 10 9 /mL EVs), as compared to a negative outcome (7.35 × 10 9 /mL EVs) possibly explaining the reduced number of miRNAs in the SCM associated with failed pregnancies. The analysis of the miRNome in the SCM of couples undergoing fertility treatment lays the ground towards development of biomarkers to predict successful pregnancy and towards understanding the role of embryonic miRNAs found in the SCM.

  20. Manganese(II) chelate contrast media

    International Nuclear Information System (INIS)

    Rocklage, S.M.; Quay, S.C.

    1994-01-01

    New chelate forming compounds for use as contrast media in NMR imaging are described. Especially mentioned are manganese(II) ion chelates of N,N' dipyridoxaldiamine, N,N' diacetic acid, and salts and esters thereof. 1 fig

  1. [Chronic otitis mediaChronic Otitis Media].

    Science.gov (United States)

    Kohles, N; Schulz, T; Eßer, D

    2015-11-01

    There are 2 different kinds of chronic otitis media: Otitis media chronica mesotympanalis and otitis media chronica epitympanalis (cholesteatoma). The incidence of chronic otitis media as reported in literature differs in a wide range. The incidence rates vary between 0.45 and 46%. Both, otitis media chronica mesotympanalis and cholesteatoma, lead to eardrum perforation due to lengthy and recurring inflammations. Furthermore, chronic otitis media is characterized by frequently recurring otorrhea and conductive hearing loss. Georg Thieme Verlag KG Stuttgart · New York.

  2. Electrodeposited ultrafine NbOx, ZrOx, and TaO x nanoparticles on carbon black supports for oxygen reduction electrocatalysts in acidic media

    KAUST Repository

    Seo, Jeongsuk

    2013-09-06

    A remarkable electrocatalytic activity was obtained for the oxygen reduction reaction (ORR) in acidic solutions on ultrafine nano-oxide catalysts based on group IV or V elements. By potentiostatic electrodepostion in nonaqueous solutions at 298 K followed by heat treatment in H2 gas, highly dispersed fine nanoparticles of NbOx, ZrOx, and TaOx with sizes of less than 5 nm were prepared and deposited on carbon black (CB) loaded electrodes. These oxide nanoparticles showed high catalytic activities with high onset potentials of 0.96 VRHE (NbOx), 1.02 VRHE (ZrOx), and 0.93 V RHE (TaOx) for the ORR. Owing to the high chemical stability of group IV and V oxides, the catalysts were very stable during the ORR in acidic solutions. Surface characterization and chemical identification were performed using scanning transmission electron microscopy (STEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). All results clearly indicate the formation of nano-oxide electrocatalysts that show an outstanding ORR performance, whereas the bulk oxides are not active because of the absence of electronic conductivity. The present work demonstrates potential candidates for highly stable, non-noble-metal cathode catalysts for polymer electrolyte fuel cells (PEFCs), where the catalysts are exposed to highly acidic and oxidizing conditions. © 2013 American Chemical Society.

  3. Fluorescence ratiometric sensing of polyols by phenylboronic acid complexes with ligands exhibiting excited-state intramolecular proton transfer in aqueous micellar media

    Energy Technology Data Exchange (ETDEWEB)

    Trejo-Huizar, Karla Elisa; Jiménez-Sánchez, Arturo; Martínez-Aguirre, Mayte A.; Yatsimirsky, Anatoly K., E-mail: anatoli@unam.mx

    2016-11-15

    2-Phenyl-3-hydroxy-4(1H)-quinolone possessing dual fluorescence due to excited-state intramolecular proton transfer (ESIPT) forms stable complex with phenylboronic acid with blue shifted emission maximum in micellar medium of a cationic surfactant even though the compound lacks required for complexation with boronic acids cis-diol structure. No complexation is observed in the presence of neutral or anionic surfactants. Titrations of this complex with polyols including sugars and nucleotides at pH 8 displace free quinolone showing ratiometric response, which allows determination of polyols with detection limits 0.05–1 mM and unusually wide linear dynamic ranges. Another ESIPT dye 2-(2′-hydroxyphenyl)−1H-benzimidazole also lacking cis-diol structure forms equally stable complex with phenylboronic acid and allows ratiometric determination of polyols with similar characteristics. The results of this study demonstrate that blocking ESIPT of signaling molecule by complexation of the receptor with the proton donor group eliminates the low energy emission from tautomeric form but strongly enhances the high energy emission typical for “normal” form of signaling molecule creating a possibility of ratiometric sensing.

  4. Electrodeposited ultrafine NbOx, ZrOx, and TaO x nanoparticles on carbon black supports for oxygen reduction electrocatalysts in acidic media

    KAUST Repository

    Seo, Jeongsuk; Cha, Dong Kyu; Takanabe, Kazuhiro; Kubota, Jun; Domen, Kazunari

    2013-01-01

    A remarkable electrocatalytic activity was obtained for the oxygen reduction reaction (ORR) in acidic solutions on ultrafine nano-oxide catalysts based on group IV or V elements. By potentiostatic electrodepostion in nonaqueous solutions at 298 K followed by heat treatment in H2 gas, highly dispersed fine nanoparticles of NbOx, ZrOx, and TaOx with sizes of less than 5 nm were prepared and deposited on carbon black (CB) loaded electrodes. These oxide nanoparticles showed high catalytic activities with high onset potentials of 0.96 VRHE (NbOx), 1.02 VRHE (ZrOx), and 0.93 V RHE (TaOx) for the ORR. Owing to the high chemical stability of group IV and V oxides, the catalysts were very stable during the ORR in acidic solutions. Surface characterization and chemical identification were performed using scanning transmission electron microscopy (STEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). All results clearly indicate the formation of nano-oxide electrocatalysts that show an outstanding ORR performance, whereas the bulk oxides are not active because of the absence of electronic conductivity. The present work demonstrates potential candidates for highly stable, non-noble-metal cathode catalysts for polymer electrolyte fuel cells (PEFCs), where the catalysts are exposed to highly acidic and oxidizing conditions. © 2013 American Chemical Society.

  5. On Media Education

    Science.gov (United States)

    Fedorov, Alexander

    2008-01-01

    This monograph analyzes the theory and practice of media education and media literacy. The book also includes the list of Russian media education literature and addresses of websites of the associations for media education.

  6. Laboratory-Scale Column Testing Using IONSIV IE-911 for Removing Cesium from Acidic Tank Waste Simulant. 1: Cesium Exchange Capacity of a 15-cm3 Column and Dynamic Stability of the Exchange Media

    International Nuclear Information System (INIS)

    T.J. Tranter; R.D. Tillotson; T.A. Todd

    2005-01-01

    Bench-scale column tests were performed using a commercial form of crystalline silicotitanate (CST) for removing radio-cesium from a surrogate acidic tank solution representative of liquid waste stored at the Idaho National Engineering and Environmental Laboratory (INEEL). An engineered form of CST ion exchanger, known as IONSIVtm IE-911 (UOP, Mt Laurel, NJ, USA), was tested in 15 cm3 columns at a flow rate of 5 bed volumes per hour. These experiments showed the ion exchange material to have reasonable selectivity and capacity for removing cesium from the complex chemical matrix of the solution. However, previous testing indicated that partial neutralization of the feed stream was necessary to increase the stability of the ion exchange media. Thus, in these studies, CST degradation was determined as a function of throughput in order to better assess the stability characteristics of the exchanger for potential future waste treatment applications. Results of these tests indicate that the degradation of the CST reaches a maximum very soon after the acidic feed is introduced to the column and then rapidly declines. Total dissolution of bed material did not exceed 3% under the experimental regime used

  7. Otitis media.

    Science.gov (United States)

    Schilder, Anne G M; Chonmaitree, Tasnee; Cripps, Allan W; Rosenfeld, Richard M; Casselbrant, Margaretha L; Haggard, Mark P; Venekamp, Roderick P

    2016-09-08

    Otitis media (OM) or middle ear inflammation is a spectrum of diseases, including acute otitis media (AOM), otitis media with effusion (OME; 'glue ear') and chronic suppurative otitis media (CSOM). OM is among the most common diseases in young children worldwide. Although OM may resolve spontaneously without complications, it can be associated with hearing loss and life-long sequelae. In developing countries, CSOM is a leading cause of hearing loss. OM can be of bacterial or viral origin; during 'colds', viruses can ascend through the Eustachian tube to the middle ear and pave the way for bacterial otopathogens that reside in the nasopharynx. Diagnosis depends on typical signs and symptoms, such as acute ear pain and bulging of the tympanic membrane (eardrum) for AOM and hearing loss for OME; diagnostic modalities include (pneumatic) otoscopy, tympanometry and audiometry. Symptomatic management of ear pain and fever is the mainstay of AOM treatment, reserving antibiotics for children with severe, persistent or recurrent infections. Management of OME largely consists of watchful waiting, with ventilation (tympanostomy) tubes primarily for children with chronic effusions and hearing loss, developmental delays or learning difficulties. The role of hearing aids to alleviate symptoms of hearing loss in the management of OME needs further study. Insertion of ventilation tubes and adenoidectomy are common operations for recurrent AOM to prevent recurrences, but their effectiveness is still debated. Despite reports of a decline in the incidence of OM over the past decade, attributed to the implementation of clinical guidelines that promote accurate diagnosis and judicious use of antibiotics and to pneumococcal conjugate vaccination, OM continues to be a leading cause for medical consultation, antibiotic prescription and surgery in high-income countries.

  8. Media matters.

    Science.gov (United States)

    Martinez, L M

    1995-01-01

    The impact of the mass media on woman's status was addressed at two 1995 conferences: the Fourth World Conference on Women, held in Beijing, China, and the Congress of the World Association for Christian Communication, held in Puebla, Mexico. The globalization process facilitated by the mass media has served to increase the power of patriarchy, with no advantages to the cause of women's rights. Coverage of popular movements has been suppressed out of deference to male-controlled governments. Coverage of the Beijing Conference highlighted celebrities and personal stories, to the exclusion of the economic and political issues under debate. Television has commodified women, reinforcing their oppression. On the other hand, the alternative media, which tend to be decentralized, democratic, low-cost, and low in technology, are presenting women as subjects rather than objects and deconstructing gender stereotypes. Of concern, however, is the tendency of computer technology to widen the gap between social classes and developed and developing countries. Women must use information networks to disseminate information on women's rights and strengthen the links between women throughout the world.

  9. Media Education Initiatives by Media Organizations: The Uses of Media Literacy in Hong Kong Media

    Science.gov (United States)

    Chu, Donna; Lee, Alice Y. L.

    2014-01-01

    As more media organizations have engaged in media education, this paper investigates the goals and practices of these activities. This article coins media education initiatives by media organizations with the term "media-organization media literac"y (MOML). Four MOML projects in Hong Kong were selected for examination. Built on critical…

  10. Highly active carbon supported ternary PdSnPtx (x=0.1-0.7) catalysts for ethanol electro-oxidation in alkaline and acid media.

    Science.gov (United States)

    Wang, Xiaoguang; Zhu, Fuchun; He, Yongwei; Wang, Mei; Zhang, Zhonghua; Ma, Zizai; Li, Ruixue

    2016-04-15

    A series of trimetallic PdSnPtx (x=0.1-0.7)/C catalysts with varied Pt content have been synthesized by co-reduction method using NaBH4 as a reducing agent. These catalysts were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and chronoamperometry (CA). The electrochemical results show that, after adding a minor amount of Pt dopant, the resultant PdSnPtx/C demonstrated more superior catalytic performance toward ethanol oxidation as compared with that of mono-/bi-metallic Pd/C or PdSn/C in alkaline solution and the PdSnPt0.2/C with optimal molar ratio reached the best. In acid solution, the PdSnPt0.2/C also depicted a superior catalytic activity relative to the commercial Pt/C catalyst. The possible enhanced synergistic effect between Pd, Sn/Sn(O) and Pt in an alloyed state should be responsible for the as-revealed superior ethanol electro-oxidation performance based upon the beneficial electronic effect and bi-functional mechanism. It implies the trimetallic PdSnPt0.2/C with a low Pt content has a promising prospect as anodic electrocatalyst in fields of alkali- and acid-type direct ethanol fuel cells. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Kinetics of corrosion inhibition of aluminum in acidic media by water-soluble natural polymeric chondroitin-4-sulfate as anionic polyelectrolyte inhibitor.

    Science.gov (United States)

    Hassan, Refat M; Ibrahim, Samia M; Takagi, Hideo D; Sayed, Suzan A

    2018-07-15

    Corrosion inhibition of aluminum (Al) in hydrochloric acid by anionic polyelectrolyte chondroitin-4-sulfate (CS) polysaccharide has been studied using both gasometrical and weight-loss techniques. The results drawn from these two techniques are comparable and exhibit negligible differences. The inhibition efficiency was found to increase with increasing the inhibitor concentration and decreased with increasing temperature. The inhibition action of CS on Al metal surface was found to obey both of Langmuir and Freundlich isotherms. The factors affecting the corrosion rates such as the concentration and geometrical structure of the inhibitor, concentration of the corrosive medium, and the temperature were examined. The kinetic parameters were evaluated and a suitable corrosion mechanism consistent with the results obtained is discussed. Copyright © 2018. Published by Elsevier Ltd.

  12. Media Matter

    Directory of Open Access Journals (Sweden)

    Holger Pötzsch

    2017-02-01

    Full Text Available The present contribution maps materialist advances in media studies. Based on the assumption that matter and materiality constitute significant aspects of communication processes and practices, I introduce four fields of inquiry - technology, political economy, ecology, and the body - and argue that these perspectives enable a more comprehensive understanding of the implications of contemporary technologically afforded forms of interaction. The article shows how each perspective can balance apologetic and apocalyptic approaches to the impact of in particular digital technologies, before it demonstrates the applicability of an integrated framework with reference to the techno-politics of NSA surveillance and the counter-practices of WikiLeaks.

  13. Media education and media influence on youth

    OpenAIRE

    LILÁK, Karel

    2011-01-01

    Bachelor´s work is focused on the questions of the medial education and the medias themselves. This work also investigate with the influence of the action of medias to the students of apprenticeship. The first part of the theoretical work has generally explains what is media education, what is its significance for society and for the benefit of education in school. They are given functions, types and objectives of media education and communications capabilities via the media. The second part ...

  14. Mechanism of the Formation of Organic Derivatives of gamma-Zirconium Phosphate by Topotactic Reactions with Phosphonic Acids in Water and Water-Acetone Media.

    Science.gov (United States)

    Alberti, G.; Giontella, E.; Murcia-Mascarós, S.

    1997-06-18

    The rates of the topotactic reactions between gamma-zirconium phosphate and phenylphosphonic acid in water and water-acetone mixtures at various temperatures were investigated. The slow rates of the process in aqueous medium or in water-acetone mixtures at temperatures lower than 50 degrees C were attributed to a slow interdiffusion of O(2)P(OH)(2)(-) and O(2)P(OH)(C(6)H(5))(-) groups in the interlayer region of gamma-ZrP. Similar to ion-exchange processes, the replacement begins in the external part of the interlayer region and progresses toward the central region with the formation of an advancing phase boundary. In water-acetone mixtures at temperatures higher than 60 degrees C an exfoliation of gamma-ZrP was found. Thus, the initial process is very fast since the substitution can take place directly on the surface of the exfoliated gamma-lamellae. However, after a certain degree of substitution, a flocculation of the colloidal dispersion, which slows down the rate of the further topotactic substitution, was observed. Some considerations on the topotactic substitution occurring on the surface of the exfoliated lamellae and on the mechanism of the diffusion of the exchanging species in the interlayer region are also reported.

  15. CO2-Free Power Generation on an Iron Group Nanoalloy Catalyst via Selective Oxidation of Ethylene Glycol to Oxalic Acid in Alkaline Media

    Science.gov (United States)

    Matsumoto, Takeshi; Sadakiyo, Masaaki; Ooi, Mei Lee; Kitano, Sho; Yamamoto, Tomokazu; Matsumura, Syo; Kato, Kenichi; Takeguchi, Tatsuya; Yamauchi, Miho

    2014-07-01

    An Fe group ternary nanoalloy (NA) catalyst enabled selective electrocatalysis towards CO2-free power generation from highly deliverable ethylene glycol (EG). A solid-solution-type FeCoNi NA catalyst supported on carbon was prepared by a two-step reduction method. High-resolution electron microscopy techniques identified atomic-level mixing of constituent elements in the nanoalloy. We examined the distribution of oxidised species, including CO2, produced on the FeCoNi nanoalloy catalyst in the EG electrooxidation under alkaline conditions. The FeCoNi nanoalloy catalyst exhibited the highest selectivities toward the formation of C2 products and to oxalic acid, i.e., 99 and 60%, respectively, at 0.4 V vs. the reversible hydrogen electrode (RHE), without CO2 generation. We successfully generated power by a direct EG alkaline fuel cell employing the FeCoNi nanoalloy catalyst and a solid-oxide electrolyte with oxygen reduction ability, i.e., a completely precious-metal-free system.

  16. Porous carbon supported Fe-N-C composite as an efficient electrocatalyst for oxygen reduction reaction in alkaline and acidic media

    Science.gov (United States)

    Liu, Baichen; Huang, Binbin; Lin, Cheng; Ye, Jianshan; Ouyang, Liuzhang

    2017-07-01

    In recent years, non-precious metal electrocatalysts for oxygen reduction reaction (ORR) have attracted tremendous attention due to their high catalytic activity, long-term stability and excellent methanol tolerance. Herein, the porous carbon supported Fe-N-C catalysts for ORR were synthesized by direct pyrolysis of ferric chloride, 6-Chloropyridazin-3-amine and carbon black. Variation of pyrolysis temperature during the synthesis process leads to the difference in ORR catalytic activity. High pyrolysis temperature is beneficial to the formation of the "N-Fe" active sites and high electrical conductivity, but the excessive temperature will cause the decomposition of nitrogen-containing active sites, which are revealed by Raman, TGA and XPS. A series of synthesis and characterization experiments with/without nitrogen or iron in carbon black indicate that the coordination of iron and nitrogen plays a crucial role in achieving excellent ORR performances. Electrochemical test results show that the catalyst pyrolyzed at 800 °C (Fe-N-C-800) exhibits excellent ORR catalytic activity, better methanol tolerance and higher stability compared with commercial Pt/C catalyst in both alkaline and acidic conditions.

  17. Addition of IrO2 to RuO2+TiO2 coated anodes and its effect on electrochemical performance of anodes in acid media

    Directory of Open Access Journals (Sweden)

    Farhad Moradi

    2014-04-01

    Full Text Available Ternary mixed metal oxide coatings with the nominal composition IrxRu(0.6−xTi0.4O2 (x=0, 0.1, 0.2, 0.3 on the titanium substrate were prepared by thermal decomposition of a chloride precursor mixture. Surface morphology and microstructure of the coatings were investigated by Scanning electron microscopy (SEM, Field emission scanning electron microscopy (FE-SEM and X-ray diffraction (XRD analysis. Systematic study of electrochemical properties of these coatings was performed by cyclic voltammetry (CV and polarization measurements. The corrosion behavior of the coatings was evaluated under accelerated conditions (j=2 A cm−2 in acidic electrolyte. The role of iridium oxide admixture in the change of electrocatalytic activity and stability of Ru0.6Ti0.4O2 coating was discussed. Small addition of IrO2 can improve the stability of the RuO2+TiO2 mixed oxide, while the electrocatalytic activity for oxygen evolution reaction (OER is decreased. The shift of redox potentials for Ru0.6Ti0.4O2 electrode that is slightly activated with IrO2 and improvement in the stability can be attributed to the synergetic effect of mixed oxide formation.

  18. Analysis of the formation of Ta{sub 2}O{sub 5} passive films in acid media through mechanistic modeling

    Energy Technology Data Exchange (ETDEWEB)

    Cabrera-Sierra, R., E-mail: roma_ipn@yahoo.com [Instituto Politecnico Nacional, Escuela Superior de Ingenieria Quimica e Industrias Extractivas, Departamento de Ingenieria Quimica Industrial, UPALM Ed. 7, 1er. Piso CP 07738, D.F. (Mexico); Vazquez-Arenas, J. [Chemical Engineering Department, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G (Canada); Cardoso, S. [Instituto Politecnico Nacional, Escuela Superior de Ingenieria Quimica e Industrias Extractivas, Departamento de Ingenieria Quimica Industrial, UPALM Ed. 7, 1er. Piso CP 07738, D.F. (Mexico); Luna-Sanchez, R.M. [Universidad Autonoma Metropolitana-Azcapotzalco, Departamento de Energia, Av. San Pablo No. 180, Col. Reynosa Tamaulipas, CP 02200, D.F. (Mexico); Trejo, M.A. [Instituto Politecnico Nacional, Escuela Superior de Ingenieria Quimica e Industrias Extractivas, Departamento de Ingenieria Quimica Industrial, UPALM Ed. 7, 1er. Piso CP 07738, D.F. (Mexico); Marin-Cruz, J. [Instituto Mexicano del Petroleo, Coordinacion de Ingenieria Molecular, Competencia de Quimica Aplicada. Eje Central Lazaro Cardenas Norte 152, CP 07730, D.F. (Mexico); Hallen, J.M. [Instituto Politecnico Nacional, Escuela Superior de Ingenieria Quimica e Industrias Extractivas, Departamento de Ingenieria Quimica Industrial, UPALM Ed. 7, 1er. Piso CP 07738, D.F. (Mexico)

    2011-09-30

    Electrochemical impedance spectroscopy (EIS) analyses are carried out to evaluate the passive features of tantalum oxide films (Ta{sub 2}O{sub 5}) formed at different potentiostatic conditions (0.5, 1.0, 1.5 and 2.0 V vs SSE). A supporting electrolyte of 0.1 M H{sub 2}SO{sub 4} (pH 1) has been used to emulate acidic corrosive conditions for the growth of films with an n-type electronic character. A modification of the point defect model (PDM) accounting for the formation of molecular hydrogen (blistering damage) is used to fit the experimental EIS diagrams, and obtain the kinetic parameters that best describe the semiconductive behavior of the passive films. After this analysis, diffusivities in the order of 5.37 {+-} 1.6 x 10{sup -17} and 1.98 {+-} 1.4 x 10{sup -20} cm{sup 2} s{sup -1} were obtained for the oxygen (D{sub VO}{center_dot}{center_dot}) and hydroxyl vacancies (D{sub VOH}{center_dot}), respectively. These findings show the capabilities of the EIS and the physicochemical modeling to account for the formation of valve-metal oxide films on a different range of conditions.

  19. Two new contrast media in coronary angiography

    International Nuclear Information System (INIS)

    Selin, K.; Bjoerk, L.

    1983-01-01

    Amipaque, ioxaglic acid and Isopaque Coronar 300 were compared in a double blind investigation of coronary angiography in patients with ischemic heart disease. Amipaque affected systolic blood pressure and ECG less than the other contrast media. Ioxaglic acid appeared to give more ST and T changes than Isopaque Coronar. (Auth.)

  20. Managing Media: Segmenting Media Through Consumer Expectancies

    Directory of Open Access Journals (Sweden)

    Matt Eastin

    2014-04-01

    Full Text Available It has long been understood that consumers are motivated to media differently. However, given the lack of comparative model analysis, this assumption is without empirical validation, and thus, the orientation of segmentation from a media management perspective is without motivational grounds. Thus, evolving the literature on media consumption, the current study develops and compares models of media segmentation within the context of use. From this study, six models of media expectancies were constructed so that motivational differences between media (i.e., local and national newspapers, network and cable television, radio, and Internet could be observed. Utilizing higher order statistical analyses the data indicates differences across a model comparison approach for media motivations. Furthermore, these differences vary across numerous demographic factors. Results afford theoretical advancement within the literature of consumer media consumption as well as provide media planners’ insight into consumer choices.

  1. Geographic Media Literacy

    Science.gov (United States)

    Lukinbeal, Chris

    2014-01-01

    While the use of media permeates geographic research and pedagogic practice, the underlying literacies that link geography and media remain uncharted. This article argues that geographic media literacy incorporates visual literacy, information technology literacy, information literacy, and media literacy. Geographic media literacy is the ability…

  2. Adolescents and media literacy.

    Science.gov (United States)

    McCannon, Robert

    2005-06-01

    In the face of media industry consolidation, fewer people control media content which makes it harder for parents and citizens to know the research about media-related issues, such as video game violence, nutrition, and sexual risk-taking. Media literacy offers a popular and potentially successful way to counter the misinformation that is spread by Big Media public relations.

  3. Safety in online media – freedom of the media; safety of media actors and media education

    OpenAIRE

    Moeller, Ch

    2013-01-01

    In this paper, prepared for the international conference ‘Mass Media – Society – Education: Media Safety Problems’ at the Chelyabinsk State University’s Department for Journalism and Media Education from September 30 – October 3, 2013, I would like to address three dimensions of media safety and security in online media.

  4. SOCIAL MEDIA SECURITY

    Science.gov (United States)

    RESPONSIBILITY CENTCOM COALITION MEDIA SOCIAL MEDIA NEWS ARTICLES PRESS RELEASES IMAGERY VIDEOS TRANSCRIPTS VISITORS AND PERSONNEL FAMILY CENTER FAMILY READINESS CENTCOM WEBMAIL SOCIAL MEDIA SECURITY ACCOUNTABILITY HomeVISITORS AND PERSONNELSOCIAL MEDIA SECURITY FAQ on Security for Social Media Due to the widespread use of

  5. Measuring News Media Literacy

    Science.gov (United States)

    Maksl, Adam; Ashley, Seth; Craft, Stephanie

    2015-01-01

    News media literacy refers to the knowledge and motivations needed to identify and engage with journalism. This study measured levels of news media literacy among 500 teenagers using a new scale measure based on Potter's model of media literacy and adapted to news media specifically. The adapted model posits that news media literate individuals…

  6. Kinetic of the reduction of neptunium by hydrazine. Pt. 5. Reduction of Np(V) to Np(IV) in nitric acid media

    Energy Technology Data Exchange (ETDEWEB)

    Koltunov, V S; Tikhonov, M F; Shapovalov, M P

    1976-01-01

    The kinetics of the reaction between Np(V) and N/sub 2/H/sub 4/ in solutions of HNO/sub 3/+NaNO/sub 3/ was studied by a spectrophotometric method and an ionic strength ..mu..=4 in a broad range of N/sub 2/H/sub 4/ concentrations (0.01-1 M) at the temperatures 80 and 96/sup 0/C. It was shown that the order of the reaction with respect to Np(V) depends on the concentration of N/sub 2/H/sub 4/. At a low concentration (0.01-0.02 M), the reaction is second order with respect to Np(V), and its mechanism includes a slow step of disproportionation of NpO/sub 2//sup +/ ions. At a high concentration of N/sub 2/H/sub 4/ (1 M) the reaction is zero order with respect to Np(V), and its mechanism consists of the slow step of oxidation of N/sub 2/H/sub 4/ by nitric acid (by NO/sub 2//sup +/ ions) and the rapid steps of oxidation of the N/sub 2/H/sub 2/ radicals formed by NpO/sub 2//sup +/ ions and dimerization of radicals. A general kinetic equation was obtained for the reaction. Its parameters were determined with an electronic computer according to the results of experiments at ..mu..=4 and 90/sup 0/C: k/sub 2/=0.158+-0.017 M/sup -3/.min/sup -1/; k=(6.26+-1.79).10/sup -5/ M/sup -2/.min/sup -1/; K=(8.9+-39).10/sup -8/ M/sup -1/, and n=1.8+-0.4. The equation corresponds to the mechanism of the reaction.

  7. Degradation of Acid Blue 25 in aqueous media using 1700kHz ultrasonic irradiation: ultrasound/Fe(II) and ultrasound/H(2)O(2) combinations.

    Science.gov (United States)

    Ghodbane, Houria; Hamdaoui, Oualid

    2009-06-01

    In this work, the sonolytic degradation of an anthraquinonic dye, C.I. Acid Blue 25 (AB25), in aqueous phase using high frequency ultrasound waves (1700kHz) for an acoustic power of 14W was investigated. The sonochemical efficiency of the reactor was evaluated by potassium iodide dosimeter, Fricke reaction and hydrogen peroxide production yield. The three investigated methods clearly show the production of oxidizing species during sonication and well reflect the sonochemical effects of high frequency ultrasonic irradiation. The effect of operational conditions such as the initial AB25 concentration, solution temperature and pH on the degradation of AB25 was studied. Additionally, the influence of addition of salts on the degradation of dye was examined. The rate of AB25 degradation was dependent on initial dye concentration, pH and temperature. Addition of salts increased the degradation of dye. Experiments conducted using distilled and natural waters demonstrated that the degradation was more efficient in the natural water compared to distilled water. To increase the efficiency of AB25 degradation, experiments combining ultrasound with Fe(II) or H(2)O(2) were conducted. Fe(II) induced the dissociation of ultrasonically produced hydrogen peroxide, leading to additional OH radicals which enhance the degradation of dye. The combination of ultrasound with hydrogen peroxide looks to be a promising option to increase the generation of free radicals. The concentration of hydrogen peroxide plays a crucial role in deciding the extent of enhancement obtained for the combined process. The results of the present work indicate that ultrasound/H(2)O(2) and ultrasound/Fe(II) processes are efficient for the degradation of AB25 in aqueous solutions by high frequency ultrasonic irradiation.

  8. Media Literacy in Times of Media Divides

    Directory of Open Access Journals (Sweden)

    Kaja Žuran

    2013-12-01

    Full Text Available We live in a post-modern society, an information society, a society based around knowledge and participation, and above all in a media society. In a media culture where media holds a dominant position, we cannot overlook the emerging idea of a ‘media divide’ within the frame of media education, media literate individuals and the expansion of the traditional concept of media literacy. Firstly, we are in an era of technological revolution, and it is time to consider the meaning and function of media and how we experience it in our everyday life. Secondly, as a society we are subject to intense media invasion and we all need to learn how to use it to our benefit and apply a critical and autonomous perspective towards selecting media content. Otherwise the media divide between the media literate and illiterate will widen; but is there even a chance to overcome the supposed divide between those who are formally media educated and those who are not?

  9. Otitis media with effusion

    Science.gov (United States)

    OME; Secretory otitis media; Serous otitis media; Silent otitis media; Silent ear infection; Glue ear ... from the tube and is swallowed. OME and ear infections are connected in two ways: After most ear ...

  10. Intermediality and media change

    OpenAIRE

    2012-01-01

    This book is about intermediality as an approach to analysing and understanding media change. Intermediality and Media Change is critical of technological determinism that characterises 'new media discourse' about the ongoing digitalization, framed as a revolution and creating sharp contrasts between old and new media. Intermediality instead emphasises paying attention to continuities between media of all types and privileges a comparative perspective on technological changes in media over ti...

  11. Media Pembelajaran Global Warming

    OpenAIRE

    Tham, Fikri Jufri; Liliana, Liliana; Purba, Kristo Radion

    2016-01-01

    Computer based learning media is one of the media has an important role in learning. Learning media will be attractive when packaged through interactive media , such as interactive media created in paper manufacture " instructional media global warming" . The advantage gained is that it can increase knowledge, generally educate people to be more concerned about the environment , and also can be a means of entertainment. This application is focused to learn about global warming and packaged in...

  12. Social media management and media environment

    Directory of Open Access Journals (Sweden)

    Šiđanin Iva

    2012-01-01

    Full Text Available The paper deals with the system of services that social media management can offer to a variety of users. As social media systems are emerging, social media management can strengthen teams in social media and help to manage numerous social channels and distribution of social information from one place. Social media management is a system of procedures that are used to manage the flow of information in the environment of social media. This involves connecting with social media like Facebook, Twitter, LinkedIn, Plaxo, Ecademy, YouTube and many others, then the aggregation and management of social data. Social media management services are analysed through various fields, such as managing multiple social media profiles, mail scheduling and filtering, reporting and analytics. Social media management enables managing personal business through social media, which contributes to a significant reduction in expenditures. The paper also discusses the importance of social media management in marketing activities and various forms of social promotion, which allow companies to easily reach their customers.

  13. Studies on the biofilm produced by Pseudomonas aeruginosa grown in different metal fatty acid salt media and its application in biodegradation of fatty acids and bioremediation of heavy metal ions.

    Science.gov (United States)

    Abinaya Sindu, P; Gautam, Pennathur

    2017-01-01

    Metal fatty acid salts (MFAS) in untreated industrial effluents cause environmental pollution. The use of biocompatible agents for remediation may help in reducing the harm caused to the ambient aquatic organism. Pseudomonas aeruginosa is a ubiquitous organism that thrives under harsh conditions and is resistant to toxic metal ions. The present study shows a proof-of-concept of using this organism in the biodegradation of MFAS. MFAS were prepared and we studied their effect on the growth of the planktonic form and the formation of biofilm by P. aeruginosa. We observed biofilm formation in the presence of all the MFAS when used as the sole carbon source, albeit the quantity of biofilm formed in the presence of cadmium and copper was less. There was no effect on the planktonic form of the organism but the formation of biofilm increased in the presence of magnesium palmitate. This study shows that metal ions play a pivotal role in the formation of biofilm. HPLC (high-performance liquid chromatography) analysis of the biofilm polysaccharide showed that hexose sugar was a major component when compared with pentose sugar. The structure of biofilm polysaccharide and the coordination of the metal ion with the biofilm polysaccharide were confirmed by FTIR (Fourier transform infrared spectroscopy) and Raman spectroscopy.

  14. Pantothenic acid biosynthesis in zymomonas

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Luan; Tomb, Jean-Francois; Viitanen, Paul V.

    2014-07-01

    Zymomonas is unable to synthesize pantothenic acid and requires this essential vitamin in growth medium. Zymomonas strains transformed with an operon for expression of 2-dehydropantoate reductase and aspartate 1-decarboxylase were able to grow in medium lacking pantothenic acid. These strains may be used for ethanol production without pantothenic acid supplementation in seed culture and fermentation media.

  15. Growth of Campylobacter incubated aerobically in fumarate-pyruvate media or media supplemented with dairy, meat, or soy extracts and peptones.

    Science.gov (United States)

    Hinton, Arthur

    2016-09-01

    The ability of Campylobacter to grow aerobically in media supplemented with fumarate-pyruvate or with dairy, meat, or soy extracts or peptones was examined. Optical densities (OD) of Campylobacter cultured in basal media, media supplemented with fumarate-pyruvate or with 1.0, 2.5, 5.0, or 7.5% beef extract was measured. Growth was also compared in media supplemented with other extracts or peptones. Finally, cfu/mL of Campylobacter recovered from basal media or media supplemented with fumarate-pyruvate, casamino acids, beef extract, soytone, or beef extract and soytone was determined. Results indicated that OD of cultures grown in media supplemented with fumarate-pyruvate or with 5.0 or 7.5% beef extract were higher than OD of isolates grown in basal media or media supplemented with lower concentrations of beef extract. Highest OD were produced by isolates grown in media supplemented with beef extract, peptone from meat, polypeptone, proteose peptone, or soytone. Also, more cfu/mL were recovered from media with fumarate-pyruvate, beef extract, soytone, or beef extract-soytone than from basal media or media with casamino acids. Findings indicate that media supplemented with organic acids, vitamins, and minerals and media supplemented with extracts or peptones containing these metabolites can support aerobic growth of Campylobacter. Published by Elsevier Ltd.

  16. A novel NMR-based assay to measure circulating concentrations of branched-chain amino acids: Elevation in subjects with type 2 diabetes mellitus and association with carotid intima media thickness.

    Science.gov (United States)

    Wolak-Dinsmore, Justyna; Gruppen, Eke G; Shalaurova, Irina; Matyus, Steven P; Grant, Russell P; Gegen, Ray; Bakker, Stephan J L; Otvos, James D; Connelly, Margery A; Dullaart, Robin P F

    2018-04-01

    Plasma branched-chain amino acid (BCAA) levels, measured on nuclear magnetic resonance (NMR) metabolomics research platforms or by mass spectrometry, have been shown to be associated with type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). We developed a new test for quantification of BCAA on a clinical NMR analyzer and used this test to determine the clinical correlates of BCAA in 2 independent cohorts. The performance of the NMR-based BCAA assay was evaluated. A method comparison study was performed with mass spectrometry (LC-MS/MS). Plasma BCAA were measured in the Insulin Resistance Atherosclerosis Study (IRAS, n = 1209; 376 T2DM subjects) and in a Groningen cohort (n = 123; 67 T2DM subjects). In addition, carotid intima media thickness (cIMT) was measured successfully in 119 subjects from the Groningen cohort. NMR-based BCAA assay results were linear over a range of concentrations. Coefficients of variation for inter- and intra-assay precision ranged from 1.8-6.0, 1.7-5.4, 4.4-9.1, and 8.8-21.3%, for total BCAA, valine, leucine, and isoleucine, respectively. BCAA quantified from the same samples using NMR and LC-MS/MS were highly correlated (R 2  = 0.97, 0.95 and 0.90 for valine, leucine and isoleucine). In both cohorts total and individual BCAA were elevated in T2DM (P = 0.01 to ≤0.001). Moreover, cIMT was associated with BCAA independent of age, sex, T2DM and metabolic syndrome (MetS) categorization or alternatively of individual MetS components. BCAA levels, measured by NMR in the clinical laboratory, are elevated in T2DM and may be associated with cIMT, a proxy of subclinical atherosclerosis. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  17. Induction of Ca2+-dependent cyclosporin A-insensitive nonspecific permeability of the inner membrane of liver mitochondria and cytochrome c release by α,ω-hexadecanedioic acid in media of varying ionic strength.

    Science.gov (United States)

    Dubinin, M V; Vedernikov, A A; Khoroshavina, E I; Samartsev, V N

    2014-06-01

    In liver mitochondria loaded with Ca2+ or Sr(2+), α,ω-hexadecanedioic acid (HDA) can induce nonspecific permeability of the inner membrane (mitochondrial pore) by the mechanism insensitive to cyclosporin A (CsA). In this work we studied the effect of ionic strength of the incubation medium on the kinetics of the processes that accompany Ca2+-dependent induction of the mitochondrial pore by fatty acid: organelle swelling, Ca2+ release from the matrix, changes in transmembrane potential (Δψ) and rate of oxygen consumption, and the release of cytochrome c from the intermembrane space. Two basic incubation media were used: sucrose medium and isotonic ionic medium containing KCl without sucrose. We found that 200 μM Ca2+ and 20 μM HDA in the presence of CsA effectively induce high-amplitude swelling of mitochondria both in the case of sucrose and in the ionic incubation medium. In the presence of CsA, mitochondria can rapidly absorb Ca2+ and retain it in the matrix for a while without reducing Δψ. Upon incubation in the ionic medium, mitochondria retain most of the added Ca2+ in the matrix for a short time without reducing the Δψ. In both cases the addition of HDA to the mitochondria 2 min after the introduction of Ca2+ leads to the rapid release of these ions from the matrix and total drop in Δψ. The mitochondrial swelling induced by Ca2+ and HDA in non-ionic medium is accompanied by almost maximal stimulation of respiration. Under the same conditions, but during incubation of mitochondria in the ionic medium, it is necessary to add cytochrome c for significant stimulation of respiration. The mitochondrial swelling induced by Ca2+ and HDA leads to the release of cytochrome c in a larger amount in the case of ionic medium than for the sucrose medium. We conclude that high ionic strength of the incubation medium determines the massive release of cytochrome c from mitochondria and liberates it from the respiratory chain, which leads to blockade of electron

  18. Media Literacy Bibliography.

    Science.gov (United States)

    Duncan, Barry

    1989-01-01

    Provides an up-to-date bibliography of resources available for teaching media literacy. Groups resources into the areas of media education methodology, mass media texts, general background, television, film, the news and medium of print, advertising, gender and the media, popular culture, popular music and rock video, periodicals, and…

  19. Understanding Social Media Logic

    OpenAIRE

    José van Dijck; Thomas Poell

    2013-01-01

    Over the past decade, social media platforms have penetrated deeply into the mech­anics of everyday life, affecting people's informal interactions, as well as institutional structures and professional routines. Far from being neutral platforms for everyone, social media have changed the conditions and rules of social interaction. In this article, we examine the intricate dynamic between social media platforms, mass media, users, and social institutions by calling attention to social media log...

  20. Social media influencer marketing

    OpenAIRE

    Isosuo, Heli

    2016-01-01

    The marketing field is changing simultaneously with the digital world. Social media is getting more and more important to marketers, and there is a need to stand out in the social media noise. Social media influencer marketing could be a good alternative to other types of marketing. A need from the consignor and the interest of the author were the motivations for conducting the study. Sääskilahti Consulting has a social media influencer network Somevaikuttajat, which is offering social media ...

  1. Unpacking New Media Literacy

    Directory of Open Access Journals (Sweden)

    Der-Thanq “victor” Chen

    2011-04-01

    Full Text Available The 21st century has marked an unprecedented advancement of new media. New media has become so pervasive that it has penetrated into every aspect of our society. New media literacy plays an essential role for any citizen to participate fully in the 21st century society. Researchers have documented that literacy has evolved historically from classic literacy (reading-writing-understanding to audiovisual literacy to digital literacy or information literacy and recently to new media literacy. A review of literature on media literacy reveals that there is a lack of thorough analysis of unique characteristics of new media and its impacts upon the notion of new media literacy. The purpose of the study is to unpack new media literacy and propose a framework for a systematic investigation of new media literacy.

  2. Parenting and Digital Media.

    Science.gov (United States)

    Coyne, Sarah M; Radesky, Jenny; Collier, Kevin M; Gentile, Douglas A; Linder, Jennifer Ruh; Nathanson, Amy I; Rasmussen, Eric E; Reich, Stephanie M; Rogers, Jean

    2017-11-01

    Understanding the family dynamic surrounding media use is crucial to our understanding of media effects, policy development, and the targeting of individuals and families for interventions to benefit child health and development. The Families, Parenting, and Media Workgroup reviewed the relevant research from the past few decades. We find that child characteristics, the parent-child relationship, parental mediation practices, and parents' own use of media all can influence children's media use, their attitudes regarding media, and the effects of media on children. However, gaps remain. First, more research is needed on best practices of parental mediation for both traditional and new media. Ideally, this research will involve large-scale, longitudinal studies that manage children from infancy to adulthood. Second, we need to better understand the relationship between parent media use and child media use and specifically how media may interfere with or strengthen parent-child relationships. Finally, longitudinal research on how developmental processes and individual child characteristics influence the intersection between media and family life is needed. The majority of children's media use takes place within a wider family dynamic. An understanding of this dynamic is crucial to understanding child media use as a whole. Copyright © 2017 by the American Academy of Pediatrics.

  3. Mass Media: The Invisible Environment.

    Science.gov (United States)

    Glessing, Robert J.; White, William P.

    This anthology for students of media consists of essays and articles grouped under four topics: media forms, media content, media environments, and "the last word." Media forms deals with the nature of these kinds of media: electronic, print, film, music, and comics, graffiti, and clothing. Media content contains articles on the news, advertising,…

  4. Media Pluralism and Diversity

    DEFF Research Database (Denmark)

    In the western world, a diverse and pluralistic media landscape is deemed essential for democracy. But how universal is media pluralism as a concept underpinning media policies? To what extent do normative approaches, regulatory dimensions and monitoring systems differ throughout the world......? Adopting a truly global, theoretical and multidisciplinary perspective, Media Pluralism and Diversity advances our understanding of media pluralism across the globe. It compares metrics developed in different parts of the world to assess levels of, or threats to, media pluralism. It identifies common...

  5. Social Media Reputation

    DEFF Research Database (Denmark)

    Etter, Michael Andreas; Ravasi, Davide; Colleoni, Elanor

    motivational drivers and contextual conditions associated with the formation of narratives in traditional news media and social media influence their content, diffusion, and impact significantly. Our analysis suggests that current theories of media reputation may provide an incomplete representation......Social media enable millions of users to create and disseminate narratives about organizations that increase their public exposure and shape public perceptions. In this paper, we draw on the sociology of news production and research on computer-mediated communication to discuss how different...... of the phenomenon, and highlight theoretically relevant differences and interrelationships between reputational dynamics involving news media and social media....

  6. AMAMM - All Media Are Mixed Media

    DEFF Research Database (Denmark)

    All Media Are Mixed Media Alle medier er blandingsmedier. Alle kunstarter er kompositte. Alle sanser er sammensatte. Alle medialiteter er miksede og mangfoldige. Alle er AMAMM. Denne påstand står centralt i ord-, billed- og medie-teoretikeren W.J.T. Mitchells forfatterskab. I hosstående bog tager...

  7. Catholic Media and Youth.

    Science.gov (United States)

    Nunes, Stephen A.

    1980-01-01

    Discusses the impact of media on youth and suggests some possible directions for the Catholic media, especially in the areas of textbooks, magazines, television, movies, and radio, in responding to the needs of youth. (Author/FM)

  8. Nurses and social media.

    Science.gov (United States)

    Farrelly, Rory

    Nurses' use of social media and other electronic communications has increased significantly with growing numbers of social media opportunities, platforms and applications including blogs, social networking sites, video sites and online chat rooms and forums.

  9. Media and Crime

    DEFF Research Database (Denmark)

    Agger, Gunhild; Waade, Anne Marit

    2011-01-01

    Recent developments in the relationship between media and crime are analyzed, taking both fiction and journalism in account......Recent developments in the relationship between media and crime are analyzed, taking both fiction and journalism in account...

  10. Development of contrast media

    International Nuclear Information System (INIS)

    Krause, W.

    1993-01-01

    Description of all contrast media (ionic and nonionic monomers, ionic and nonionic dimers) was presented. Chemotoxicity, osmolality and viscosity of some contrast agents were analyzed. The main adverse reactions to ionic and nonionic contrast media were described

  11. The social media revolution.

    Science.gov (United States)

    Dubose, Cheryl

    2011-01-01

    The growing popularity and use of social media tools such as Facebook, YouTube, Twitter, blogging, and wikis have led to a social media revolution. Given this widespread influence, it is important for educators, administrators, and technologists to understand the risks of using social media in the classroom and workplace. To investigate popular social media sites and their effect on radiologic technology education and business practices. A comprehensive search of literature was performed to examine social media and its applications in education, health care, and business. Social media use is on the rise, affecting all aspects of mainstream society. Leaders in the radiologic sciences should be familiar with social media and cognizant of its risks. Future studies regarding social media use in the radiologic sciences are necessary to determine its effect on the radiologic science community. ©2011 by the American Society of Radiologic Technologists.

  12. MODERN MEDIA EDUCATION MODELS

    Directory of Open Access Journals (Sweden)

    Alexander Fedorov

    2011-03-01

    Full Text Available The author supposed that media education models can be divided into the following groups:- educational-information models (the study of the theory, history, language of media culture, etc., based on the cultural, aesthetic, semiotic, socio-cultural theories of media education;- educational-ethical models (the study of moral, religions, philosophical problems relying on the ethic, religious, ideological, ecological, protectionist theories of media education;- pragmatic models (practical media technology training, based on the uses and gratifications and ‘practical’ theories of media education;- aesthetical models (aimed above all at the development of the artistic taste and enriching the skills of analysis of the best media culture examples. Relies on the aesthetical (art and cultural studies theory; - socio-cultural models (socio-cultural development of a creative personality as to the perception, imagination, visual memory, interpretation analysis, autonomic critical thinking, relying on the cultural studies, semiotic, ethic models of media education.

  13. STORAGE STABILITY OF PESTICIDES IN EXTRACT SOLVENTS AND SAMPLING MEDIA

    Science.gov (United States)

    Demonstrating that pesticides are stable in field media and their extracts over extended storage periods allows operational flexibility and cost efficiency. Stability of the 31 neutral pesticides and 2 acid herbicides of the Agricultural Health Study exposure pilot was evaluate...

  14. Asian Media Productions

    DEFF Research Database (Denmark)

    This work consists of 12 essays on different aspects of Asian media by Japanese, European, and American scholars, many of whom have themselves been involved in the production of media forms. Working in the fields of anthropology, media and cultural studies, and on the basis of hands-on research, ......, they have written a book on the social practices and cultural attitudes of people producing, reading, watching and listening to different kinds of media in Japan, China, Taiwan, Indonesia, Vietnam, Singapore and India....

  15. Advertising on social media

    OpenAIRE

    Sumit Goyal

    2013-01-01

    This communication reports the latest trends of advertising on social media. Social media advertising means to gain traffic or attention of online users through social media sites. Today, when a user thinks about buying something, he first comes to the internet, searches for that product, compares its price with other competing brands and takes a decision, which one to buy. In this write-up, author has discussed many aspects concerning advertising through social media, viz., what is social me...

  16. Procedural Media Representation

    OpenAIRE

    Henrysson, Anders

    2002-01-01

    We present a concept for using procedural techniques to represent media. Procedural methods allow us to represent digital media (2D images, 3D environments etc.) with very little information and to render it photo realistically. Since not all kind of content can be created procedurally, traditional media representations (bitmaps, polygons etc.) must be used as well. We have adopted an object-based media representation where an object can be represented either with a procedure or with its trad...

  17. Media Education: Sociology Surveys

    Science.gov (United States)

    Fedorov, Alexander

    2007-01-01

    In Russia as well as in foreign countries we can witness sort of the confusion of the terms of "media education" and "media literacy". There are quite a few differences in theoretical approaches to media education, to distinguishing of the most important aims, objectives, means of introduction into the teaching process, etc.…

  18. Modern Media Education Models

    Science.gov (United States)

    Fedorov, Alexander

    2011-01-01

    The author supposed that media education models can be divided into the following groups: (1) educational-information models (the study of the theory, history, language of media culture, etc.), based on the cultural, aesthetic, semiotic, socio-cultural theories of media education; (2) educational-ethical models (the study of moral, religions,…

  19. Open Media Science

    DEFF Research Database (Denmark)

    Martiny, Kristian Møller Moltke; Pedersen, David Budtz; Hansted, Alfred Birkegaard

    2016-01-01

    and extend into a fully-fledged Open Media movement engaging with new media and non-traditional formats of science communication. We discuss two cases where experiments with open media have driven new collaborations between scientists and documentarists. We use the cases to illustrate different advantages...

  20. Children's Media Policy

    Science.gov (United States)

    Jordan, Amy B.

    2008-01-01

    Amy Jordan addresses the need to balance the media industry's potentially important contributions to the healthy development of America's children against the consequences of excessive and age-inappropriate media exposure. Much of the philosophical tension regarding how much say the government should have about media content and delivery stems…

  1. Social Media Empowerment (I)

    NARCIS (Netherlands)

    A. Cox

    2011-01-01

    full text via link. Social media stellen mensen, merken en bedrijven in staat om zichzelf te versterken. Soms wordt optimaal gebruik gemaakt van Social Media Empowerment, maar soms ook wat minder. Effectief inzetten van social media. Regel 1: Start met context en motivatie

  2. Youth media lifestyles

    NARCIS (Netherlands)

    van Kruistum, Claudia; Leseman, Paul Pm; de Haan, Mariëtte

    2014-01-01

    In this article, the concept of "media lifestyles" is adopted in order to develop a comprehensive approach toward youth engagement in communication media. We explore how 503 Dutch eighth grade students with full access to new technology combine a broad range of media by focusing on their engagement

  3. Sizing Up Social Media

    Science.gov (United States)

    Pearson, Jerold

    2010-01-01

    Most people are aware of the increasing importance of social media to institutional advancement, and many colleges and universities have started investing resources in these media. The next step is to measure the impact of social media on the institution and evaluate the success of one's efforts. Every advancement leader should understand how…

  4. The Media Reader.

    Science.gov (United States)

    Valdes, Joan; Crow, Jeanne

    An anthology of readings in the media correlates chapter-by-chapter to the authors' textbook, "The Media Works." Fifteen chapters cover the study of newspapers, magazines, comics, popular music, television, movies, and advertising. The authors included represent varied perspectives on the media. The selections were chosen with the help of a…

  5. Media and child development

    NARCIS (Netherlands)

    Piotrowski, J.T.; Vossen, H.G.M.; Valkenburg, P.M.; Wright, J.D.

    2015-01-01

    Decades of research have shown that the relationship between media and childhood is not unidirectional but reciprocal. In this article, both directions of the media-child development relationship are presented. We discuss how child development predisposes children's media use and preferences by

  6. Interfacial forces in aqueous media

    CERN Document Server

    van Oss, Carel J

    2006-01-01

    Thoroughly revised and reorganized, the second edition of Interfacial Forces in Aqueous Media examines the role of polar interfacial and noncovalent interactions among biological and nonbiological macromolecules as well as biopolymers, particles, surfaces, cells, and both polar and apolar polymers. The book encompasses Lifshitz-van der Waals and electrical double layer interactions, as well as Lewis acid-base interactions between colloidal entities in polar liquids such as water. New in this Edition: Four previously unpublished chapters comprising a new section on interfacial propertie

  7. Notes for media reinvention

    Directory of Open Access Journals (Sweden)

    Jesús Miguel Flores-Vivar

    2009-10-01

    Full Text Available Journalism and media are going through a change of era. This change is reflected in the transformation of journalism and media-lived and that another major in 1980 that became known as mediamorphosis, by this, professionals have to learn new roles. The impact of information technology and Internet has changed the way how you present the news and, most importantly, transform the business model that has characterized media companies. This article analyzes the current situation provides some strategic guidelines to be followed by some media-and-do and studied some of the new profiles arebeginning to emerge as a result of the reinvention of journalism and the media.

  8. Prosocial effects of media.

    Science.gov (United States)

    Hogan, Marjorie J

    2012-06-01

    Parents, teachers, health care providers, and other caring adults worry about the harmful influence of media messages and images on children and teens and wonder how to recognize and encourage positive and healthy use of media. For decades, experts have commented on the power of media. Media depictions can lead to negative attitudes and behavior in some young viewers. This article discusses whether prosocial, tolerant, and cooperative attitudes and behavior can be learned and imitated by children and adolescents and whether media can nurture or stimulate creativity or actively promote health and well-being in young consumers. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Comprehension of digital media

    International Nuclear Information System (INIS)

    Kim, Ju Hwan

    2008-11-01

    This book is divided four parts. The first part describes media and mark on sign and media, what is the sign?, interpretation of sign and semiotics. The second part is for production sign theory and origin of digital revolution such as the problem of origin of digital revolution, homogeneity of producing goods and sign : triple triangle model for production sign theory, triple triangle model for producing goods, triple triangle model of producing sign and triple triangle model of art works. The third parts deals with development of the media and meaning of digital revolution with four changes : invention of letter, appearance of printed media and establishment modernity, appearance electronic media and mess media and appearance of digital media. The last part mentions ontology of world wide web.

  10. The Media Mixer

    DEFF Research Database (Denmark)

    Vestergaard, Vitus; Mortensen, Christian Hviid

    2011-01-01

    content. The media content is created by the user in the museum's physical environment, but it can be mixed with material from web archives. It is the intention that the users learn about media through participatory and creative processes with media where the borders between producing, playing......We explore how remixing and content sharing can be used as a means for user participation in a digital museum age. Remix culture is seen as a culture that allows and encourages the production of derivative works; works that are based on already existing works. This cultural practice thrives...... throughout the Internet, most notably on web 2.0 sites like YouTube. The Media Museum has embraced the remix paradigm with the development of an interactive media experience centre called the Media Mixer. Here the museum users can produce, deconstruct, reconstruct and finally publish and share digital media...

  11. Radiographic contrast media

    International Nuclear Information System (INIS)

    Golman, K.; Holtz, E.; Almen, T.

    1987-01-01

    Contrast media are used in diagnostic radiology to enhance the X-ray attenuation between a body structure of interest and the surrounding tissue. A detail becomes perceptible on a roentgenogram only when its contrast exceeds a minimum value in relation to the background. Small areas of interest must have higher contrast than the background. The contrast effect depends on concentration of the contrast media with the body. A high contrast media concentration difference thus gives rise to more morphological details in the radiographs. Contrast media can be divided into negative contrast media such as air and gas which attenuate X-rays less than the body tissues, and positive contrast materials which attenuate X-rays more than the body tissues. The positive contrast media all contain either iodine (atomic number 53) or barium (atomic number 56) and can be divided into water-insoluble and water-soluble contrast media

  12. Comprehension of digital media

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ju Hwan

    2008-11-15

    This book is divided four parts. The first part describes media and mark on sign and media, what is the sign?, interpretation of sign and semiotics. The second part is for production sign theory and origin of digital revolution such as the problem of origin of digital revolution, homogeneity of producing goods and sign : triple triangle model for production sign theory, triple triangle model for producing goods, triple triangle model of producing sign and triple triangle model of art works. The third parts deals with development of the media and meaning of digital revolution with four changes : invention of letter, appearance of printed media and establishment modernity, appearance electronic media and mess media and appearance of digital media. The last part mentions ontology of world wide web.

  13. Media:Time card stack

    NARCIS (Netherlands)

    Annemarie Wennekers; Jos de Haan; Frank Huysmans

    2016-01-01

    Original title: Media:Tijd in kaart The Dutch spend a daily average of 8 hours 33 minutes using media. Men and people aged over 50 spend most time using media, at an average of 9 hours per day. Older media users prefer traditional media and devices over new media and modern devices. Young and

  14. Understanding Social Media Logic

    Directory of Open Access Journals (Sweden)

    José van Dijck

    2013-08-01

    Full Text Available Over the past decade, social media platforms have penetrated deeply into the mech­anics of everyday life, affecting people's informal interactions, as well as institutional structures and professional routines. Far from being neutral platforms for everyone, social media have changed the conditions and rules of social interaction. In this article, we examine the intricate dynamic between social media platforms, mass media, users, and social institutions by calling attention to social media logic—the norms, strategies, mechanisms, and economies—underpin­ning its dynamics. This logic will be considered in light of what has been identified as mass me­dia logic, which has helped spread the media's powerful discourse outside its institutional boundaries. Theorizing social media logic, we identify four grounding principles—programmabil­ity, popularity, connectivity, and datafication—and argue that these principles become increas­ingly entangled with mass media logic. The logic of social media, rooted in these grounding principles and strategies, is gradually invading all areas of public life. Besides print news and broadcasting, it also affects law and order, social activism, politics, and so forth. Therefore, its sustaining logic and widespread dissemination deserve to be scrutinized in detail in order to better understand its impact in various domains. Concentrating on the tactics and strategies at work in social media logic, we reassess the constellation of power relationships in which social practices unfold, raising questions such as: How does social media logic modify or enhance ex­isting mass media logic? And how is this new media logic exported beyond the boundaries of (social or mass media proper? The underlying principles, tactics, and strategies may be relat­ively simple to identify, but it is much harder to map the complex connections between plat­forms that distribute this logic: users that employ them, technologies that

  15. Transport in Stochastic Media

    International Nuclear Information System (INIS)

    Haran, O.; Shvarts, D.; Thieberger, R.

    1998-01-01

    Classical transport of neutral particles in a binary, scattering, stochastic media is discussed. It is assumed that the cross-sections of the constituent materials and their volume fractions are known. The inner structure of the media is stochastic, but there exist a statistical knowledge about the lump sizes, shapes and arrangement. The transmission through the composite media depends on the specific heterogeneous realization of the media. The current research focuses on the averaged transmission through an ensemble of realizations, frm which an effective cross-section for the media can be derived. The problem of one dimensional transport in stochastic media has been studied extensively [1]. In the one dimensional description of the problem, particles are transported along a line populated with alternating material segments of random lengths. The current work discusses transport in two-dimensional stochastic media. The phenomenon that is unique to the multi-dimensional description of the problem is obstacle bypassing. Obstacle bypassing tends to reduce the opacity of the media, thereby reducing its effective cross-section. The importance of this phenomenon depends on the manner in which the obstacles are arranged in the media. Results of transport simulations in multi-dimensional stochastic media are presented. Effective cross-sections derived from the simulations are compared against those obtained for the one-dimensional problem, and against those obtained from effective multi-dimensional models, which are partially based on a Markovian assumption

  16. Media relations after the introduction of social media

    OpenAIRE

    Mesila, Helin

    2010-01-01

    In the light of the popularity of social media on one hand, and the contradictive relationships between journalists and public relations practitioners on the other hand, the thesis studies media relations after the introduction of social media. The study focuses on media relations in Estonian public relations scenery. The research answers to the questions: - What are media relations today? - What are the functions of social media and media relations in organizational communication? ...

  17. Media education and media enlightenment as attributes of information society

    Directory of Open Access Journals (Sweden)

    Лилия Борисовна Белоглазова

    2014-12-01

    Full Text Available The article deals with the problem of the functioning of media-education and media-enlightenment in modern society. Focuses on the impact of this socio-cultural phenomenon on consciousness of members of the Information Society. Are the main characteristics of media-education and media-education and media-enlightenment. Concludes that media-education and media-enlightenment forms unscientific and anti-scientific thinking and style speech.

  18. Organizational Communication and Media

    DEFF Research Database (Denmark)

    Tække, Jesper

      The paper reflects an interest in the relation between organizational communication and media. It tries to answer the question, how we can observe the relationship between organizational communication and media. It is a work-in-progress which tries to combine organizational studies inspired...... of Niklas Luhmann (Tække & Paulsen 2008, Tække 2008a) with analysis of how organizations communicate in and about media. Using systems theory and form theory, it puts forward a theoretical framework and a strategy for analysing organisational communication in and about media. The medium aspect is inspired...... is a possible framework to draw the two disciplines together in, because it is a theory about the relation between the social and the media it is based on. First the paper sum up the Luhmann inspired theory about organizations, fleshing out how organizations are thought to communicate in and about media and how...

  19. Social media visibility

    DEFF Research Database (Denmark)

    Uldam, Julie

    2018-01-01

    of activists remains under-researched. This article examines BP’s surveillance of activists who criticise the company’s corporate social responsibility (CSR) programme as ‘greenwashing’. In this way, it goes beyond corporations’ uses of big data and instead explores how they monitor and discuss strategies......As activists move from alternative media platforms to commercial social media platforms, they face increasing challenges in protecting their online security and privacy. While government surveillance of activists is well-documented in scholarly research and the media, corporate surveillance...... for responding to the activities of individual activists in social media. It shows that while social media afford an unprecedented level of visibility for activists, it comes with the risk of being monitored by corporations. Theoretically, it draws on conceptions of visibility in social sciences and media...

  20. The Media Mixer

    DEFF Research Database (Denmark)

    Vestergaard, Vitus; Mortensen, Christian Hviid

    In recent years many museums have experimented with different approaches to involving users through digital media. We explore how remixing and content sharing can be used as a means for user participation. Remix culture is seen as a culture that allows and encourages the production of derivative...... works; works that are based on already existing works. This cultural practice thrives throughout the Internet, most notably on web2.0 sites like YouTube. The Media Museum has embraced the remix paradigm with the development of an interactive media experience centre called the Media Mixer. Here...... the museum users can produce, deconstruct, reconstruct and finally publish and share digital media content. The media content is created by the user in the museums physical environment, but it can be mixed with material from local or global archives. In that way the gap between the analogue and the digital...

  1. Abortion in the media.

    Science.gov (United States)

    Conti, Jennifer A; Cahill, Erica

    2017-12-01

    To review updates in how abortion care is depicted and analysed though various media outlets: news, television, film, and social media. A surge in recent media-related abortion research has recognized several notable and emerging themes: abortion in the news media is often inappropriately sourced and politically motivated; abortion portrayal in US film and television is frequently misrepresented; and social media has a new and significant role in abortion advocacy. The portrayal of abortion onscreen, in the news, and online through social media has a significant impact on cultural, personal, and political beliefs in the United States. This is an emerging field of research with wide spread potential impact across several arenas: medicine, policy, public health.

  2. Internal Social Media

    DEFF Research Database (Denmark)

    Madsen, Vibeke Thøis

    2018-01-01

    Internal social media is a web-based communication arena that provides all organizational members with a communication opportunity. The media has emerged in organizations since 2004, and is increasingly seen as a way of giving employees a voice in organizations which can benefit the organization...... in terms of knowledge sharing, collaboration, and employee participation and engagement. The first wave of studies of internal social media was primarily from an information-systems perspective and focused more on its adoption, its affordances, and the outcome of its introduction. The second wave...... of studies was more concerned with studying the dynamics of communication on internal social media, in order to understand coworkers as strategic communicators and how communication on internal social media can constitute the organization. With a successful introduction of internal social media, coworkers...

  3. New Media, New Citizens?

    DEFF Research Database (Denmark)

    Ohme, Jakob

    as for different age groups, the thesis shows that digital and especially social media use can be a strong driver of citizen participation. Besides looking at immediate mobilizing effects, the book sheds light on how digital media use may shape participation patterns through a long-term change in citizenship......The use of news media is regarded as a driver for citizens’ engagement with society and their political participation. But as news media use increasingly shifts to digital platforms, it is crucial to understand the interplay between a changing media environment and recent patterns of political...... participation. Against the background of citizens’ diverse possibilities for receiving political information and being politically active nowadays, the book focuses on the impact of digital media on political participation in Denmark. By examining this relationship in election- and non-election times as well...

  4. Orchestrating the Media Collage

    Science.gov (United States)

    Ohler, Jason

    2009-01-01

    Modern literacy has always meant being able to both read and write narrative in the media forms of the day, whatever they may be. Just being able to read is not sufficient. A new dimension of literacy is now in play--namely, the ability to adapt to new media forms and fit them into the overall media collage quickly and effectively. A strong case…

  5. The digital media handbook

    CERN Document Server

    Dewdney, Andrew

    2013-01-01

    The new edition of The Digital Media Handbook presents an essential guide to the historical and theoretical development of digital media, emphasising cultural continuity alongside technological change, and highlighting the emergence of new forms of communication in contemporary networked culture.Andrew Dewdney and Peter Ride present detailed critical commentary and descriptive historical accounts, as well as a series of interviews from a range of digital media practitioners, including producers, developers, curators and artists.The Digital Media Handbook highlights key concerns of today's prac

  6. Media Monopoly in Brazil.

    Science.gov (United States)

    Amaral, Roberto; Guimaraes, Cesar

    1994-01-01

    Documents the process of broadcasting media development in Brazil, the failure of new technologies to produce democratization, and the barriers to democratization erected by monopolization and "metastasis." (SR)

  7. Overview: new media.

    Science.gov (United States)

    O'Keeffe, Gwenn Schurgin

    2012-06-01

    Pediatricians care for children's growth and development from the time they are born until they become adults. In addition, pediatricians must be vigilant for external influences. Technology influences children of all ages. Seventy-five percent of teenagers own cell phones, with 25% using them for social media. Technology can lead to an increase in skills and social benefits but there is also the potential for harm such as sexting, cyberbullying, privacy issues, and Internet addiction, all of which can affect health. Pediatricians must become well versed in the new media to provide media-oriented anticipatory guidance and advice on media-related issues. Copyright © 2012 Elsevier Inc. All rights reserved.

  8. Antennas in inhomogeneous media

    CERN Document Server

    Galejs, Janis; Fock, V A; Wait, J R

    2013-01-01

    Antennas in Inhomogeneous Media details the methods of analyzing antennas in such inhomogeneous media. The title covers the complex geometrical configurations along with its variational formulations. The coverage of the text includes various conditions the antennas are subjected to, such as antennas in the interface between two media; antennas in compressible isotropic plasma; and linear antennas in a magnetoionic medium. The selection also covers insulated loops in lossy media; slot antennas with a stratified dielectric or isotropic plasma layers; and cavity-backed slot antennas. The book wil

  9. Media multitasking in adolescence.

    Science.gov (United States)

    Cain, Matthew S; Leonard, Julia A; Gabrieli, John D E; Finn, Amy S

    2016-12-01

    Media use has been on the rise in adolescents overall, and in particular, the amount of media multitasking-multiple media consumed simultaneously, such as having a text message conversation while watching TV-has been increasing. In adults, heavy media multitasking has been linked with poorer performance on a number of laboratory measures of cognition, but no relationship has yet been established between media-multitasking behavior and real-world outcomes. Examining individual differences across a group of adolescents, we found that more frequent media multitasking in daily life was associated with poorer performance on statewide standardized achievement tests of math and English in the classroom, poorer performance on behavioral measures of executive function (working memory capacity) in the laboratory, and traits of greater impulsivity and lesser growth mindset. Greater media multitasking had a relatively circumscribed set of associations, and was not related to behavioral measures of cognitive processing speed, implicit learning, or manual dexterity, or to traits of grit and conscientiousness. Thus, individual differences in adolescent media multitasking were related to specific differences in executive function and in performance on real-world academic achievement measures: More media multitasking was associated with poorer executive function ability, worse academic achievement, and a reduced growth mindset.

  10. Open Media Science

    DEFF Research Database (Denmark)

    Møller Moltke Martiny, Kristian; Pedersen, David Budtz; Hansted, Allan Alfred Birkegaard

    2016-01-01

    In this article, we present three challenges to the emerging Open Science (OS) movement: the challenge of communication, collaboration and cultivation of scientific research. We argue that to address these challenges OS needs to include other forms of data than what can be captured in a text...... and extend into a fully-fledged Open Media movement engaging with new media and non-traditional formats of science communication. We discuss two cases where experiments with open media have driven new collaborations between scientists and documentarists. We use the cases to illustrate different advantages...... of using open media to face the challenges of OS....

  11. Composition of commercial media used for human embryo culture.

    Science.gov (United States)

    Morbeck, Dean E; Krisher, Rebecca L; Herrick, Jason R; Baumann, Nikola A; Matern, Dietrich; Moyer, Thomas

    2014-09-01

    To determine the composition of commercially available culture media and test whether differences in composition are biologically relevant in a murine model. Experimental laboratory study. University-based laboratory. Cryopreserved hybrid mouse one-cell embryos were used in experiments. Amino acid, organic acid, ions, and metal content were determined for two different lots of media from Cook, In Vitro Care, Origio, Sage, Vitrolife, Irvine CSC, and Global. To determine whether differences in the composition of these media are biologically relevant, mouse one-cell embryos were thawed and cultured for 120 hours in each culture media at 5% and 20% oxygen in the presence or absence of protein in an EmbryoScope time-lapse incubator. The compositions of seven culture media were analyzed for concentrations of 39 individual amino acids, organic acids, ions, and elements. Blastocyst rates and cell cycle timings were calculated at 96 hours of culture, and the experiments were repeated in triplicate. Of the 39 analytes, concentrations of glucose, lactate, pyruvate, amino acids, phosphate, calcium, and magnesium were present in variable concentrations, likely reflecting differences in the interpretation of animal studies. Essential trace elements, such as copper and zinc, were not detected. Mouse embryos failed to develop in one culture medium and were differentially affected by oxygen in two other media. Culture media composition varies widely, with differences in pyruvate, lactate, and amino acids especially notable. Blastocyst development was culture media dependent and showed an interaction with oxygen concentration and presence of protein. Copyright © 2014 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  12. Ligand solvation effect on Dy3+ complexing with benzoic, p-, o-, m-aminobenzoic, 4-pyridinecarboxylic acids., and with pyridine and 4-aminopyridine in aqua and aqua-organic media

    International Nuclear Information System (INIS)

    Elistratova, Yu.G.; Mustafina, A.R.; Devyatov, F.V.; Sarvarova, N.N.

    1996-01-01

    Substituent effect on stability of Dy 3+ complexes with aminobenzoic acids (o , p-, m-isomers), pyridinecarboxylic acids and p-aminopyridine was estimated on the base of pH-metric and magnetooptic data. It was concluded that the more the efficiency of ligand's solvation the less the substituent effects the complex stability. 15 refs., 3 figs., 2 tabs

  13. Making Media Studies

    Directory of Open Access Journals (Sweden)

    David Gauntlett

    2015-12-01

    Full Text Available This podcast is a recording of a research seminar that took place on December 3, 2015, at the University of Westminster's Communication and Media Research Institute (CAMRI. In this contribution, David Gauntlett discusses his new book, Making Media Studies, and other new work. In Making Media Studies (Peter Lang, 2015, Gauntlett proposes a vision of media studies based around doing and making – not about the acquisition of skills, as such, but an experience of building knowledge and understanding through creative hands-on engagement with all kinds of media. Gauntlett suggests that media studies scholars have failed to recognise the significance of everyday creativity – the vital drive of people to make, exchange, and learn together, supported by online networks. He argues that we should think about media in terms of conversations, inspirations, and making things happen. Media studies can be about genuine social change, he suggests, if we recognise the significance of everyday creativity, work to transform our tools, and learn to use them wisely. David Gauntlett is a Professor in the School of Media, Arts and Design at the University of Westminster, where he is also the School's Co-Director of Research. He is the author of several books, including: Creative Explorations (2007, Media, Gender and Identity: An Introduction (2nd edition 2008, Making is Connecting (2011, and Making Media Studies (2015. He has made a number of popular online resources, videos and playthings, and has pioneered creative research and workshop methods. He is external examiner for Information Experience Design at the Royal College of Art, London.

  14. Educational Potential of New Media

    Directory of Open Access Journals (Sweden)

    Maria Yu. Kazak

    2017-11-01

    Full Text Available Digitalization of the mass media, which has radically changed the information environment, creates new opportunities for self-education and upgrowth of the audience. The paper defines the communicative and cultural status of new media, characterizes the socio-cultural and technological aspects of their dynamics; substantiates the necessity of elaborating mechanisms for systematization of heterogeneous information flows and elaborating criteria for their evaluation in the era of globalization of the media sphere, what implies a qualitatively different level of media competence of the audience, provided with such factors as media education, media coverage, media criticism. The definition of concepts "media competence", "media enlightenment", "media education", "media criticism" is given and their functional areas are delineated. Social networks are considered as an important tool for media enlightenment which provides significant opportunities for promoting cultural achievements in the new media environment.

  15. Media Anthropology: A Theoretical Framework

    Science.gov (United States)

    Eiselein, E. B.; Topper, Martin

    1976-01-01

    Media anthropology, a diverse field, has involved nearly all the major subdisciplines of anthropology and most of the major media in five different areas of interaction: the study of media, reaching the public, gathering data, teaching with media, and applied media anthropology. (NQ)

  16. Japanese Media in English.

    Science.gov (United States)

    Tanaka, Sachiko Oda

    1995-01-01

    Describes the use of English in the media in Japan, focusing on the role and history of English-language newspapers, radio, and television programs, as well as the proliferation of English-language films shown in Japanese cinemas. Discusses the implications of English in the Japanese media. (20 references) (MDM)

  17. Advertising Pressures on Media.

    Science.gov (United States)

    Hammitt, Harry

    The majority of the media in the United States is funded through revenues derived from the sale of advertising space. The problem that arises from this situation is fundamentally an economic one: if advertisers are paying the bills for the media, how much control over content should they have? This report offers a review of instances in which…

  18. Corporeal-Locomotive Media

    DEFF Research Database (Denmark)

    Nørgård, Rikke Toft

    and experiences such as reading or listening to a story and watching a movie or theatre play and other traditional or new media forms. These circumstances make the article question whether digital games can be understood as (new) media form at all and, thus, it points towards a possible new vocabulary...... for and comprehension of digital games, gameplay and gameplayers....

  19. A Religious Media Revolution?

    DEFF Research Database (Denmark)

    Skovgaard-Petersen, Jakob

    2016-01-01

    This article is a preliminary survey of the media usage of Sunni religious actors during the Syrian conflict. It traces the adoption of new media by religious actors, and analyses the kind of authority these actors have sought to embody, whether regime supporting, oppositional or jihadist...

  20. Loneliness and Media Gratifications.

    Science.gov (United States)

    Canary, Daniel J.; Spitzberg, Brian H.

    1993-01-01

    Assesses the nature of the relationship between experienced loneliness and media gratifications. Finds that chronically lonely college students rely less on media for escape than do others and that they reported the least motivation for watching their favorite soap opera. (SR)

  1. Media Entertainment and emotions

    DEFF Research Database (Denmark)

    Tan, Ed S.

    2017-01-01

    The chapter presents a psychological framework for entertainment experiences. It reviews types of emotion and their associations with media entertainment contents, explaining the role of genre.......The chapter presents a psychological framework for entertainment experiences. It reviews types of emotion and their associations with media entertainment contents, explaining the role of genre....

  2. Men, Myth, and Media.

    Science.gov (United States)

    Thoman, Elizabeth, Ed.; Silver, Rosalind, Ed.

    1989-01-01

    This issue on gender and the media contains the following (1) "Home, Home on the Remote"; (2) "Dads Through the Decades" (Mark Crispin Miller); (3) "The New Man: That's Entertainment!" (John Lehrer); (4) "Singing Men's Songs" (Kerry Skorlich); (5) "Media Myths and Men's Work" (Ian Harris); (6) "Why Are There No Asian Male Anchors?" (Ben…

  3. Austria: Media Dependence.

    Science.gov (United States)

    Signitzer, Benno

    1978-01-01

    Describes the Austrian broadcast industry which is dominated by foreign influences. Suggests the restoration of autonomy of Austria's media through a system of promotion of and subsidies to Austrian media efforts, as well as a decentralization of foreign influence to increase the quality and competitiveness of domestic production. (JMF)

  4. Mapping Media and Meaning

    DEFF Research Database (Denmark)

    Chamberlain, Alan; Bødker, Mads; Papangelis, Konstantinos

    2017-01-01

    places and intangible personal content can be used to develop meaningful experiences. The paper explores the use of autoethnography as a method for soundscape design in the fields of personal heritage and locative media. Specifically, we explore possible connections between digital media, space...

  5. Understanding social media logic

    NARCIS (Netherlands)

    van Dijck, J.; Poell, T.

    2013-01-01

    Over the past decade, social media platforms have penetrated deeply into the mech­anics of everyday life, affecting people's informal interactions, as well as institutional structures and professional routines. Far from being neutral platforms for everyone, social media have changed the conditions

  6. Literacy, Learning, and Media.

    Science.gov (United States)

    Adams, Dennis; Hamm, Mary

    2000-01-01

    Considers the expanding definition of literacy from traditional reading and writing skills to include technological, visual, information, and networking literacy. Discusses the impact of media on social interactions and intellectual development; linking technology to educational goals; influences of new media symbol systems on communication;…

  7. Introduction to Media.

    Science.gov (United States)

    Riler, Robert

    Designed for senior high school students, this one semester course focuses on four aspects of modern media: television, film, radio, and advertising. Each topic is worked into a weekly lesson plan format that stresses the active involvement of students in the learning process. The course outline contains lists of objectives and media materials…

  8. Work in the Media

    NARCIS (Netherlands)

    Deuze, M.

    2014-01-01

    As media have become dominant players in society’s affairs and, as an industry, represent a powerful economic and symbolic force, it is disheartening to see that work across the creative industries is becoming increasingly precarious. At the same time, media practitioners address this precarity in a

  9. Corporate Media Governance

    NARCIS (Netherlands)

    Kempen, Petrus Cornelis

    2011-01-01

    The media can make or break a reputation. This being said, it seems to be essential for companies, governments and institutions to pay specific attention to corporate media management in their daily operations. However, this thesis shows that they often neglect to pay adequate attention to corporate

  10. Building Social Media Connections

    Science.gov (United States)

    Ferriter, William N.; Ramsden, Jason T.; Sheninger, Eric C.

    2012-01-01

    Incorporating social media tools into your professional practices does not have to be intimidating as long as you are willing to tackle five action steps. It is far easier to articulate the strengths--and to imagine the possibilities--of social media spaces as tools for communication and professional development when you are actively using those…

  11. Trolling new media: violent extremist groups recruiting through social media

    OpenAIRE

    Chang, Mark D.

    2015-01-01

    Approved for public release; distribution is unlimited With the advent and subsequent growth of several new media technologies, violent extremist groups have incorporated social media into recruiting strategies. How are violent extremist groups using social media for recruiting? This thesis explores several new media technologies—websites, blogs, social media, mobile phones, and online gaming—to determine if violent extremist groups rely on social media for recruiting. By comparing the com...

  12. Komunikasi Krisis di Era New Media dan Social Media

    OpenAIRE

    Prastya, Narayana Mahendra

    2016-01-01

    New media and social media have changed the practice of public relations. One area that changed is crisis communication. Because of these new technologies, crisis can be more complex. The pace of information, the uncertainty, and the rumors, are increasing. Public relations practitioners should include the new media and social media use in their crisis communication plan. Before doing that, public relations practitioners should change their mindset about social media and new media. The first ...

  13. Populism and the media

    DEFF Research Database (Denmark)

    Esser, Frank; Stepinska, Agnieszka; Hopmann, David Nicolas

    2017-01-01

    European media systems have gone through major changes in the last few decades, and these changes have included increased opportunity structures for the dissemination of populist messages. Chapter 12 (‘Switzerland’) rightly states that the disappearance of the traditional party press, increased...... media ownership concentration, dependence on advertising, and a stronger orientation toward news values have worked in favor of a growing populist discourse. The newly established online media are seen as having a high afnity to populism’s rhetorical persuasion because both aim for the “quick kick....../click” with a broad audience. As was stated in Chapter 1 in this volume, the role that the media play in the dissemination of populism is largely under-explored. In the classical research literature dealing with populism (see, e.g., Canovan, 1981; Taggart, 2000), communication and media are not addressed at all. When...

  14. Media Sociography on Weblogs

    DEFF Research Database (Denmark)

    Tække, Jesper

    Weblogs are not only one of the newest technical media for communication, but also one of the most difficult to understand. Are weblogs a kind of mass medium, a personal medium like an online diary, or a medium that gives space for communities to grow? Or are weblogs a medium that enable all...... these possibilities depended on the actual use? This paper throws some light on what weblogs are by using the methodology of Media Sociography (Tække 2003, 2004a, 2004b and 2004c). Media Sociography is a strategy for analysing mediated social systems or in other words a strategy for describing the social in relation...... to the media it is based on. Theoretically seen it is inspired of two theoretical paradigms the Sociological Systems Theory of Niklas Luhmann and the Media Theory (also called the Toronto school). Empirically the paper primary draws on the literature about weblogs, which could be framed as CMC...

  15. Social Media in Organizations

    DEFF Research Database (Denmark)

    Razmerita, Liana; Kirchner, Kathrin; Nabeth, Thierry

    2014-01-01

    By using social media, many companies try to exploit new forms of interaction, collaboration, and knowledge sharing through leveraging the social, collaborative dimension of social software. The traditional collective knowledge management model based on a top-down approach is now opening up new...... avenues for a bottom-up approach incorporating a more personal knowledge management dimension, which could be synergized into collective knowledge using the social-collaborative dimension of social media. This article addresses the following questions: (1) How can social media support the management...... of personal and collective knowledge using a synergetic approach? (2) Do the personal and collective dimensions compete with each other or can they reinforce each other in a more effective manner using social media? Our findings indicate that social media supports both the personal and collective dimensions...

  16. Social Media Reputation

    DEFF Research Database (Denmark)

    Etter, Michael; Colleoni, Elanor; Ravasi, Davide

    directly to corporate performance and actions. Secondly, prominent reputation measurements couple stakeholders´ believes to reputation drivers through the use of predefined scales and items. We argue that with the rise of social media a company´s reputation has increasingly become autonomous from corporate...... actions, which demands a greater decoupling of stakeholders´ perceptions from corporate signals or actions in corporate reputation research. We develop the concept of social media reputation as the overall evaluation of a company presented in social media and present a new approach of measuring reputation...... based on social media data that accounts for the autonomy of stakeholder´s perception of a firm. We compare and contrast this novel social media reputation measure (SMRM) with traditional reputation measurements and find that SMRM is a valuable measurement to capture the autonomy of the stakeholders...

  17. Balancing media environments

    DEFF Research Database (Denmark)

    Olesen, Mogens

    The paper examines how students in Danish upper secondary schools experience the uses and effects of the digital environment in relation to their school activities. Theoretically a media ecological perspective (Strate 2006) is applied which understands teaching and learning practices as shaped...... by the interrelation between teacher, student and the media technologies. According to this perspective, media creates an environment that shapes our possibilities for acting and communicating. In a basic sense, teaching and learning is a communicative situation where, traditionally, the teacher sends information...... to the receiving students through a medium (e.g. speech, blackboard, book or online learning platform). Digital media challenge this situation due to their affordances (Gibson 1979) for interactivity. Affordance has become an increasingly popular term within media studies for describing a complementary...

  18. From media crossing to media mining

    NARCIS (Netherlands)

    de Jong, Franciska M.G.; Piperidis, S.; Cunningham, H.; Tablan, V.

    2006-01-01

    This paper reviews how the concept of Media Crossing has contributed to the advancement of the application domain of information access and explores directions for a future research agenda. These will include themes that could help to broaden the scope and to incorporate the concept of

  19. Social Justice and Media. Media Corner.

    Science.gov (United States)

    Braun, Joseph A., III, Ed.

    1994-01-01

    Contends that the end of slavery, women's suffrage, and the civil rights movement were watershed events of social justice in U.S. history. Provides reviews of two media-based sets of instructional materials that can help students understand the struggle by disenfranchised groups to become full participants in society. (CFR)

  20. Effect of various amino acids on shoot regeneration of sugarcane ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-04-06

    Apr 6, 2009 ... Full Length Research Paper. Effect of various amino acids .... maize, sorghum, pineapple, rice and other monocots to enhance somatic ... without additional amino acids, making a total of 26 treatments. All culture media were ...

  1. Social media modeling and computing

    CERN Document Server

    Hoi, Steven CH; Boll, Susanne; Xu, Dong; Jin, Rong; King, Irwin

    2011-01-01

    Presents contributions from an international selection of preeminent experts in the field Discusses topics on social-media content analysis, and examines social-media system design and analysis Describes emerging applications of social media

  2. Bullying and social media affordances

    OpenAIRE

    Brailas, Alexios

    2016-01-01

    What constitutes a good and sustainabledigital living?Social media literacyCan we talk about social media intelligence?Can we talk about digital intelligence?How bullying is complicated by special social media affordances?

  3. MediaTracker system

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval, D. M. (Dana M.); Strittmatter, R. B. (Richard B.); Abeyta, J. D. (Joline D.); Brown, J. (John); Marks, T. (Thomas), Jr.; Martinez, B. J. (Benny J.); Jones, D. B. (Dana Benelli); Hsue, W.

    2004-01-01

    The initial objectives of this effort were to provide a hardware and software platform that can address the requirements for the accountability of classified removable electronic media and vault access logging. The Media Tracker system software assists classified media custodian in managing vault access logging and Media Tracking to prevent the inadvertent violation of rules or policies for the access to a restricted area and the movement and use of tracked items. The MediaTracker system includes the software tools to track and account for high consequence security assets and high value items. The overall benefits include: (1) real-time access to the disposition of all Classified Removable Electronic Media (CREM), (2) streamlined security procedures and requirements, (3) removal of ambiguity and managerial inconsistencies, (4) prevention of incidents that can and should be prevented, (5) alignment with the DOE's initiative to achieve improvements in security and facility operations through technology deployment, and (6) enhanced individual responsibility by providing a consistent method of dealing with daily responsibilities. In response to initiatives to enhance the control of classified removable electronic media (CREM), the Media Tracker software suite was developed, piloted and implemented at the Los Alamos National Laboratory beginning in July 2000. The Media Tracker software suite assists in the accountability and tracking of CREM and other high-value assets. One component of the MediaTracker software suite provides a Laboratory-approved media tracking system. Using commercial touch screen and bar code technology, the MediaTracker (MT) component of the MediaTracker software suite provides an efficient and effective means to meet current Laboratory requirements and provides new-engineered controls to help assure compliance with those requirements. It also establishes a computer infrastructure at vault entrances for vault access logging, and can

  4. MediaTracker system

    International Nuclear Information System (INIS)

    Sandoval, D.M.; Strittmatter, R.B.; Abeyta, J.D.; Brown, J.; Marks, T. Jr.; Martinez, B.J.; Jones, D.B.; Hsue, W.

    2004-01-01

    The initial objectives of this effort were to provide a hardware and software platform that can address the requirements for the accountability of classified removable electronic media and vault access logging. The Media Tracker system software assists classified media custodian in managing vault access logging and Media Tracking to prevent the inadvertent violation of rules or policies for the access to a restricted area and the movement and use of tracked items. The MediaTracker system includes the software tools to track and account for high consequence security assets and high value items. The overall benefits include: (1) real-time access to the disposition of all Classified Removable Electronic Media (CREM), (2) streamlined security procedures and requirements, (3) removal of ambiguity and managerial inconsistencies, (4) prevention of incidents that can and should be prevented, (5) alignment with the DOE's initiative to achieve improvements in security and facility operations through technology deployment, and (6) enhanced individual responsibility by providing a consistent method of dealing with daily responsibilities. In response to initiatives to enhance the control of classified removable electronic media (CREM), the Media Tracker software suite was developed, piloted and implemented at the Los Alamos National Laboratory beginning in July 2000. The Media Tracker software suite assists in the accountability and tracking of CREM and other high-value assets. One component of the MediaTracker software suite provides a Laboratory-approved media tracking system. Using commercial touch screen and bar code technology, the MediaTracker (MT) component of the MediaTracker software suite provides an efficient and effective means to meet current Laboratory requirements and provides new-engineered controls to help assure compliance with those requirements. It also establishes a computer infrastructure at vault entrances for vault access logging, and can accommodate

  5. Social Media Marketing in Russia

    OpenAIRE

    Olgskaya, Kristina

    2017-01-01

    Social media marketing involves the use of social media for connecting with prospective consumers. The study focuses on explaining such notions like social media marketing (SMM), types of SMM, differences between social media and traditional marketing, social media marketing plan, development ways of strategic social media marketing plan and why strategy may fail. This thesis also presents research in Russian social network – Vkontakte, where promotion of Mechanical Engineering programme ...

  6. CLASSICAL MEDIA RELATIONS AND NEW MEDIA RELATIONS IN SPORT

    Directory of Open Access Journals (Sweden)

    Alexandru Lucian MIHAI

    2014-06-01

    Full Text Available Media relations in sport mean maintenance of networks and positive relationships with people in the media to obtain positive media exposure for a sport product (informal and formal information sessions with media representatives. Because of the pervasive influence the media has on marketing success, sport marketers must make concerted efforts to create a positive relationship between their sport event and the media. They may accomplish this by providing the media with press releases, having news conferences, having media-day events (in which the media are invited to interact with the players, coaches, and administrators, providing media guides for the respective sport events and so on. Each of these activities promotes active involvement from the media, which will subsequently contribute to relationship building with the community.

  7. Social Media and Bullshit

    Directory of Open Access Journals (Sweden)

    Rasmus Kleis Nielsen

    2015-04-01

    Full Text Available To understand the role of social media in society, we have to understand how social media are understood. We need to analyze how different actors and organizations see and think about technology, the forms of knowledge that people draw on as they make sense of, develop, and use social media. Central among these is bullshit. This short essay discusses bullshit as defined by the philosopher Harry Frankfurt as statements made with little or no concern for their truth-value or justification and argues that social media are accompanied by unusually large amounts of bullshit for two reasons. First, they confront us with epistemological problems and are hard to understand. Second, there is a large demand for knowledge about what they mean, a powerful political economy that generates a lot of statements about social media, including substantial amounts of bullshit. Given the rapid development of social media and their growing importance, this is unlikely to change in the near future. Bullshit is here to stay, and we need to take it seriously intellectually and analytically to understand social media.

  8. Media Literacy in Montenegro

    Directory of Open Access Journals (Sweden)

    Jelena Perovic

    2015-12-01

    Full Text Available Few countries in the world have introduced media education into their curriculums. Montenegro became one of them in 2009, when “media literacy” was introduced as an optional subject for 16 and 17 year old students of Gymnasium high schools. This article presents the findings of the first and only research conducted so far on media education in Montenegro. It is a national case study which examines the potential of media education to change the school culture and accelerate education system reform towards embracing the new digital education paradigm in the future. The focus is on the results of research conducted through in-depth interviews with media literacy teachers all over the country. Despite the many challenges, all teachers identify the potential of media education to strengthen some of the key competences of the students and to improve their motivation and academic performance. They also identify potential to change positively school culture by transforming teachers into “cultural mediators” (Morcellini, 2007 and by supporting the formation of a “participative culture” (Jenkins & Kelley, 2013 in schools. This research recommends focusing education reform on spreading the media education pedagogy to the entire curriculum in order to embrace the new digital education paradigm in the future.

  9. Turkish Press in Social Media

    OpenAIRE

    AYTEN, Adem

    2013-01-01

    Social media, is one of the most researched facts today by the commications fellows. To get in use by Web 2.0 social media becomes common due to the rise of using mobile technologies. Instead of competing with traditional media and being an alternative media, social media is a new media that traditional media can transfer its content to it and can benefit its advantages. Indeed,the traditional media carried its content to the websites to access of their readers/listeners/watchers to compete ...

  10. Media multitasking and implicit learning.

    Science.gov (United States)

    Edwards, Kathleen S; Shin, Myoungju

    2017-07-01

    Media multitasking refers to the simultaneous use of different forms of media. Previous research comparing heavy media multitaskers and light media multitaskers suggests that heavy media multitaskers have a broader scope of attention. The present study explored whether these differences in attentional scope would lead to a greater degree of implicit learning for heavy media multitaskers. The study also examined whether media multitasking behaviour is associated with differences in visual working memory, and whether visual working memory differentially affects the ability to process contextual information. In addition to comparing extreme groups (heavy and light media multitaskers) the study included analysis of people who media multitask in moderation (intermediate media multitaskers). Ninety-four participants were divided into groups based on responses to the media use questionnaire, and completed the contextual cueing and n-back tasks. Results indicated that the speed at which implicit learning occurred was slower in heavy media multitaskers relative to both light and intermediate media multitaskers. There was no relationship between working memory performance and media multitasking group, and no relationship between working memory and implicit learning. There was also no evidence for superior performance of intermediate media multitaskers. A deficit in implicit learning observed in heavy media multitaskers is consistent with previous literature, which suggests that heavy media multitaskers perform more poorly than light media multitaskers in attentional tasks due to their wider attentional scope.

  11. Wet SiO2 As a Suitable Media for Fast and Efficient Reduction of Carbonyl Compounds with NaBH3CN under Solvent-Free and Acid-Free Conditions

    International Nuclear Information System (INIS)

    Kouhkan, Mehri; Zeynizadeh, Behzad

    2010-01-01

    Reduction of carbonyl compounds such as aldehydes, ketones, α,β-unsaturated enals and enones, α-diketones and acyloins was carried out readily with NaBH 3 CN in the presence of wet SiO 2 as a neutral media. The reactions were performed at solvent-free conditions in oil bath (70 - 80 .deg. C) or under microwave irradiation (240 W) to give the product alcohols in high to excellent yields. Regioselective 1,2-reduction of conjugated carbonyl compounds took place in a perfect selectivity without any side product formation

  12. Wet SiO{sub 2} As a Suitable Media for Fast and Efficient Reduction of Carbonyl Compounds with NaBH{sub 3}CN under Solvent-Free and Acid-Free Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kouhkan, Mehri; Zeynizadeh, Behzad [Urmia University, Urmia (Iran, Islamic Republic of)

    2010-10-15

    Reduction of carbonyl compounds such as aldehydes, ketones, α,β-unsaturated enals and enones, α-diketones and acyloins was carried out readily with NaBH{sub 3}CN in the presence of wet SiO{sub 2} as a neutral media. The reactions were performed at solvent-free conditions in oil bath (70 - 80 .deg. C) or under microwave irradiation (240 W) to give the product alcohols in high to excellent yields. Regioselective 1,2-reduction of conjugated carbonyl compounds took place in a perfect selectivity without any side product formation.

  13. Ethics and social media.

    Science.gov (United States)

    Milton, Constance L

    2014-10-01

    Nurses' use of social media has increased significantly with growing numbers of media-sharing opportunities, platforms, and emerging forms of electronic applications. With the proliferation, opportunities and limitations surface regarding the responsibilities and accountability that nurses have in choosing technology applications with an embedded philosophical ethos that is consistent with the discipline's societal mandate of serving humankind in ways that honor human dignity. This article begins a discussion addressing possible disciplinary obligations and responsibilities for the implementation of social media platforms and possible implications for its future use in the discipline of nursing. © The Author(s) 2014.

  14. Media and ICT

    DEFF Research Database (Denmark)

    Media and information and communication technologies (ICTs) have in the past decades been placed firmly on the educational agenda, and will continue to maintain this position, not least as catalysts for educational change. This issue is reflected in the anthology as it aims to respond...... to the question of how the presence of media and ICT in and outside schools both change and qualify educational practice as well as how the cooperation between media, cultures, aesthetics and social relations affect and support new demands on education. The book represents different academic perspectives...

  15. Open Media Science

    DEFF Research Database (Denmark)

    Møller Moltke Martiny, Kristian; Pedersen, David Budtz; Hansted, Allan Alfred Birkegaard

    2016-01-01

    In this article, we present three challenges to the emerging Open Science (OS) movement: the challenge of communication, collaboration and cultivation of scientific research. We argue that to address these challenges OS needs to include other forms of data than what can be captured in a text...... and extend into a fully-fledged Open Media movement engaging with new media and non-traditional formats of science communication. We discuss two cases where experiments with open media have driven new collaborations between scientists and documentarists. We use the cases to illustrate different advantages...

  16. Homogenization of discrete media

    International Nuclear Information System (INIS)

    Pradel, F.; Sab, K.

    1998-01-01

    Material such as granular media, beam assembly are easily seen as discrete media. They look like geometrical points linked together thanks to energetic expressions. Our purpose is to extend discrete kinematics to the one of an equivalent continuous material. First we explain how we build the localisation tool for periodic materials according to estimated continuum medium type (classical Cauchy, and Cosserat media). Once the bridge built between discrete and continuum media, we exhibit its application over two bidimensional beam assembly structures : the honey comb and a structural reinforced variation. The new behavior is then applied for the simple plan shear problem in a Cosserat continuum and compared with the real discrete solution. By the mean of this example, we establish the agreement of our new model with real structures. The exposed method has a longer range than mechanics and can be applied to every discrete problems like electromagnetism in which relationship between geometrical points can be summed up by an energetic function. (orig.)

  17. Spotlight on the media

    CERN Multimedia

    2007-01-01

    Do you want to know more about how the media works, how to deal with journalists? How to maximise opportunity and minimise threat? Then please join us on 22 November. This session will cover how to work effectively with the media, including print, radio and TV. You’ll get an insight into how journalists and news rooms operate. You’ll learn to recognise both soft balls and traps - and develop the techniques for dealing with them. The challenges of explaining CERN to any media outlet will be dealt with too. This interactive presentation, given by Jessica Pryce-Jones, Managing Director of the consultancy firm iOpener Ltd, and Nisha Pillai, news anchor for BBC World, will be illustrated with various case studies. How to deal with the media: maximising opportunity and minimising threat Thursday 22 November, from 4.30 pm, Main Auditorium, Bldg. 500 Coffee break before the event at 4.00 pm

  18. Technetium Sorption Media Review

    International Nuclear Information System (INIS)

    Duncan, J.B.; Kelly, S.E.; Robbins, R.A.; Adams, R.D.; Thorson, M.A.; Haass, C.C.

    2011-01-01

    This report presents information and references to aid in the selection of 99Tc sorption media for feasibility studies regarding the removal of 99Tc from Hanford's low activity waste. The report contains literature search material for sorption media (including ion exchange media) for the most tested media to date, including SuperLig 639, Reillex HPQ, TAM (Kruion), Purolite A520E and A530E, and Dowex 1X8. The U.S. Department of Energy (DOE), Office of River Protection (ORP) is responsible for management and completion of the River Protection Project (RPP) mission, which comprises both the Hanford Site tank farms and the Waste Treatment and Immobilization Plant (WTP). The RPP mission is to store, retrieve and treat Hanford's tank waste; store and dispose of treated wastes; and close the tank farm waste management areas and treatment facilities in a safe, environmentally compliant, cost-effective and energy-effective manner.

  19. New Media as Software

    Directory of Open Access Journals (Sweden)

    Manuel Portela

    2014-03-01

    Full Text Available Review of Lev Manovich, Software Takes Command: Extending the Language of New Media. London: Bloomsbury, 2013, 358 pp. ISBN 978-1-6235-6817-7. In Lev Manovich’s most recent book, this programmatic interrogation of our medial condition leads to the following question: do media still exist after software? This is the question that triggers Manovich’s dialogue both with computing history and with theories of digital media of recent decades, including the extension of his own previous formulations in The Language of New Media, published in 2001, and which became a major reference work in the field. The subtitle of the new book points precisely to this critical revisiting of his earlier work in the context of ubiquitous computing and accelerated transcoding of social, cultural and artistic practices by software.

  20. Creative Digital Media Practices

    DEFF Research Database (Denmark)

    Frølunde, Lisbeth

    , 2006, 2009), machinima (machine + cinema + anime, real-time animation captured in games etc.), and the digital storytelling movement. A dialogic perspective on the diversity of digital media practices opens up for understanding the complex evolution of language on socio-historical, cultural......The presentation reviews the interplay of dialogic (Bakhtin, 1981) and multimodal theories on media production practices, with attention to visual communication (Kress and van Leeuwen, 2001, 2006). This theoretical approach aids in reflecting on digital media practices as novel (new) sign systems...... develop a collaborative digital storytelling showcase for their own digital stories about Roskilde University. This course is intended to bring up reflections on the wider phenomenon of contemporary media practices, such as: YouTube, DIY (do-it-yourself) filmmaking or homemade, garage cinema (Jenkins...

  1. Stochastic porous media equations

    CERN Document Server

    Barbu, Viorel; Röckner, Michael

    2016-01-01

    Focusing on stochastic porous media equations, this book places an emphasis on existence theorems, asymptotic behavior and ergodic properties of the associated transition semigroup. Stochastic perturbations of the porous media equation have reviously been considered by physicists, but rigorous mathematical existence results have only recently been found. The porous media equation models a number of different physical phenomena, including the flow of an ideal gas and the diffusion of a compressible fluid through porous media, and also thermal propagation in plasma and plasma radiation. Another important application is to a model of the standard self-organized criticality process, called the "sand-pile model" or the "Bak-Tang-Wiesenfeld model". The book will be of interest to PhD students and researchers in mathematics, physics and biology.

  2. Terrorism as Media Event

    Directory of Open Access Journals (Sweden)

    2012-07-01

    Full Text Available Proving that terrorism should be seen as a media event (as defined by Dayan and Katzafter 9/11 and treated accordingly. We have turned to the work of Dayan and Katz and GeorgeGerbner’s for a definition of media events and of violence in the mass media. This paper is ahermeneutical interpretation of the concept of terrorism and its relation to communication. We haveput forward a better understanding of the complex concept of terrorism and its definitions in the massmedia context. Terrorism nowadays should always be defined within its inherent relation with themedia. The article is the first to define terrorism as media evenit in Dayan and Katz’s terms.

  3. TECHNETIUM SORPTION MEDIA REVIEW

    Energy Technology Data Exchange (ETDEWEB)

    DUNCAN JB; KELLY SE; ROBBINS RA; ADAMS RD; THORSON MA; HAASS CC

    2011-08-25

    This report presents information and references to aid in the selection of 99Tc sorption media for feasibility studies regarding the removal of 99Tc from Hanford's low activity waste. The report contains literature search material for sorption media (including ion exchange media) for the most tested media to date, including SuperLig 639, Reillex HPQ, TAM (Kruion), Purolite A520E and A530E, and Dowex 1X8. The U.S. Department of Energy (DOE), Office of River Protection (ORP) is responsible for management and completion of the River Protection Project (RPP) mission, which comprises both the Hanford Site tank farms and the Waste Treatment and Immobilization Plant (WTP). The RPP mission is to store, retrieve and treat Hanford's tank waste; store and dispose of treated wastes; and close the tank farm waste management areas and treatment facilities in a safe, environmentally compliant, cost-effective and energy-effective manner.

  4. Media, journalism, objectivity

    Directory of Open Access Journals (Sweden)

    Vlajki Emil

    2013-01-01

    Full Text Available This is the text around the themes: Media and Journalism, are confronted two directions of opinions: humanism and elitism. Humanism believes that media and journalism must be metaphysically objective: able to tell the truth regardless of time, place and terms of events. Another approach, elitism, is connected with Hegel's philosophy of history. Hegel's conceptual apparatus includes: Idea, History dialectic, 'cunning mind,' self- development and self-realization. In this context, media and journalism are considered as organic unity, an inseparable part of some dialectical totality. More specifically media and journalism can be objective only if they defend concrete ideological assumptions of society to which they belong. Any other understanding of these two concepts is non-objective, mere moralizing and / or demagoguery.

  5. Media and manipulation

    Directory of Open Access Journals (Sweden)

    Kovačević Braco

    2013-01-01

    Full Text Available The role and importance of the media are huge, both in everyday life and in cultural, spiritual and political life of modern man. Their power in the sense of political shaping of people and shaping of public opinion is very distinctive. In the process of propaganda to influence public opinion, they use various manipulative procedures in order to accomplish certain interests and objectives. Through the media, politics realizes its economic, ideological, political and even military activities. The war in the former Yugoslavia and former Bosnia and Herzegovina was also waged through the media. This media war still is spreading the hate speech, thus still causing conflicts and disintegration processes in the Balkans.

  6. Media and Security Team

    Data.gov (United States)

    Federal Laboratory Consortium — The Media And Security Team led by Prof. Min Wu was established in Fall 2001 at University of Maryland, College Park. A number of research and education activities...

  7. Social Media Policies

    DEFF Research Database (Denmark)

    Stohl, Cynthia; Etter, Michael; Banghart, Scott

    2017-01-01

    of these trends is examined through a content analysis of 112 publicly available social media policies from the largest corporations in the world. The extent to which social media policies facilitate and/or constrain the communicative sensibilities and values associated with contemporary notions of CSR...... negotiation and participation in the social responsibilities of corporations. Moreover, policies generally enact organizational communication practices that are contrary to international CSR guidelines (e.g., the UN Global Compact and other international agreements). Findings suggest that social media...... policies represent a relatively unrecognized development in the institutionalization of CSR communicative norms and practices that call into question the promising affordances of social media for the inclusion of various voices in the public negotiation of what constitutes corporate social responsibility....

  8. Social Media and Teaching

    DEFF Research Database (Denmark)

    Tække, Jesper; Paulsen, Michael

    New research in the Danish upper secondary schools shows that social media like Facebook is the number one attention diverts from the interaction about educational subjects in the classroom. At the same time international research shows that there is a great potential in using social media....... The overriding purpose of the paper is to provide a research-based input to the discussion about the role of social media in schools....... the past seven years (Paulsen & Tække 2009, 2010; Tække & Paulsen 2010). To find out if and how the gap can be reduced, we have initiated the action research project The Socio Media Education Experiment, and in the paper we explain both the background for the project and its preliminary results...

  9. Consolidating Social Media Strategies

    DEFF Research Database (Denmark)

    Gyimóthy, Szilvia; Munar, Ana Maria; Larson, Mia

    2014-01-01

    This study revisits and integrates the insights of recent studies on emergent social media strategies deployed by destination and event management organisations. In a comparative analysis Munar (2012) identified four generic approaches pursued by national tourism boards in the Nordic region, while...... Gyimóthy & Larson (2014) portrayed three digital value co-creation strategies deployed by festival social media. Both frameworks provided novel analytical typologies which identified a series of categories (mimetic, analytic, immersion, advertising and insourcing, crowdsourcing and community consolidation......). This paper discusses the complementary nature of these conceptual proposals and advances an integrated conceptual framework of social media strategies. Based on the empirical findings of a case study that revisits evolving digital and social media strategies of European DMOs this paper maps the dynamics...

  10. Media studies for scientists

    CERN Multimedia

    2002-01-01

    "Science, with its inherent uncertainties, can be hard to put across to the public. But blaming 'sloppy' journalism is too easy. If researchers are to make their points effectively, they should learn more about how the media work" (1 page).

  11. The News Media Industry

    National Research Council Canada - National Science Library

    Bartlett, Charlie

    2003-01-01

    American news media has two fundamental roles in our democracy: that of eyewitness, giving citizens critical information, and also as the watchdog, providing another arm of "checks and balances" within our governmental system...

  12. Efficient degradation of tannic acid by black Aspergillus species

    NARCIS (Netherlands)

    Van Diepeningen, Anne D; Debets, Alfons J M; Varga, Janos; van der Gaag, Marijn; Swart, Klaas; Hoekstra, Rolf F

    A set of aspergillus strains from culture collections and wild-type black aspergilli isolated on non-selective media were used to validate the use of media with 20% tannic acid for exclusive and complete selection of the black aspergilli. The 20% tannic acid medium proved useful for both

  13. Efficient degradation of tannic acid by black Aspergillus species

    NARCIS (Netherlands)

    Diepeningen, van A.D.; Debets, A.J.M.; Varga, J.; Gaag, van der M.; Swart, K.; Hoekstra, R.F.

    2004-01-01

    A set of aspergillus strains from culture collections and wild-type black aspergilli isolated on non-selective media were used to validate the use of media with 20 % tannic acid for exclusive and complete selection of the black aspergilli. The 20% tannic acid medium proved useful for both

  14. Communications and media services

    Science.gov (United States)

    Mcculla, James W.; Kukowski, James F.

    1990-01-01

    NASA's internal and external communication methods are reviewed. NASA information services for the media, for the public, and for employees are discussed. Consideration is given to electron information distribution, the NASA TV-audio system, the NASA broadcast news service, astronaut appearances, technology and information exhibits, speaker services, and NASA news reports for internal communications. Also, the NASA worldwide electronic mail network is described and trends for future NASA communications and media services are outlined.

  15. Drupal 7 media

    CERN Document Server

    Tal, Liran

    2013-01-01

    This is a practical, hands-on guide packed with examples that will help you build rich Drupal 7 media web applications.If you are a Drupal site builder and you wish to spice up your web applications with rich media content, then this book is for you. A basic understanding of HTML, JavaScript, and basic PHP module development in Drupal would be helpful, but is not necessary.

  16. Chernobyl and the media

    Energy Technology Data Exchange (ETDEWEB)

    Dibdin, T.

    The way the media reported the Chernobyl nuclear reactor accident was discussed at a day seminar in Birmingham in July. Contributors were from the Forsmark nuclear power station in Sweden where the disaster was first noticed, the International Atomic Energy Agency, the Russian film industry, French TV and SCRAM. Personal experiences and opinions of Chernobyl and the media were discussed. The approach in West Germany, France, Finland and the United Kingdom is compared.

  17. Chernobyl and the media

    International Nuclear Information System (INIS)

    Dibdin, T.

    1987-01-01

    The way the media reported the Chernobyl nuclear reactor accident was discussed at a day seminar in Birmingham in July. Contributors were from the Forsmark nuclear power station in Sweden where the disaster was first noticed, the International Atomic Energy Agency, the Russian film industry, French TV and SCRAM. Personal experiences and opinions of Chernobyl and the media were discussed. The approach in West Germany, France, Finland and the United Kingdom is compared. (UK)

  18. Digital Media Ethics

    DEFF Research Database (Denmark)

    Ess, Charles

    Provides a philosophical-ethical "toolkit" for analyzing central ethical issues evoked by our use of new media, including privacy, copyright, violent and sexual content online, and cross-cultural communication online.......Provides a philosophical-ethical "toolkit" for analyzing central ethical issues evoked by our use of new media, including privacy, copyright, violent and sexual content online, and cross-cultural communication online....

  19. Social Media Cocreation Strategies

    DEFF Research Database (Denmark)

    Gyimóthy, Szilvia; Larson, Mia

    2015-01-01

    This paper explores how social media becomes a part of integrated marketing communications of festival organizations. The purpose of this paper is to conceptualize the co-creation of festival experiences online by comparing managerial strategies and communicative patterns of three large....... Based on the empirical findings, we propose an analytical framework to improve our understanding of the management of social media communications, offering three distinct value co-creation strategies in a festival context....

  20. Percolation in Heterogeneous Media

    International Nuclear Information System (INIS)

    Vocka, Radim

    1999-01-01

    This work is a theoretical reflection on the problematic of the modeling of heterogeneous media, that is on the way of their simple representation conserving their characteristic features. Two particular problems are addressed in this thesis. Firstly, we study the transport in porous media, that is in a heterogeneous media which structure is quenched. A pore space is represented in a simple way - a pore is symbolized as a tube of a given length and a given diameter. The fact that the correlations in the distribution of pore sizes are taken into account by a construction of a hierarchical network makes possible the modeling of porous media with a porosity distributed over several length scales. The transport in the hierarchical network shows qualitatively different phenomena from those observed in simpler models. A comparison of numerical results with experimental data shows that the hierarchical network gives a good qualitative representation of the structure of real porous media. Secondly, we study a problem of the transport in a heterogeneous media which structure is evolving during the time. The models where the evolution of the structure is not influenced by the transport are studied in detail. These models present a phase transition of the same nature as that observed on the percolation networks. We propose a new theoretical description of this transition, and we express critical exponents describing the evolution of the conductivity as a function of fundamental exponents of percolation theory. (author) [fr

  1. Media, risk and science

    CERN Document Server

    Allan, Stuart

    2002-01-01

    How is science represented by the media? Who defines what counts as a risk, threat or hazard, and why? In what ways do media images of science shape public perceptions? What can cultural and media studies tell us about current scientific controversies? "Media, Risk and Science" is an exciting exploration into an array of important issues, providing a much needed framework for understanding key debates on how the media represent science and risk. In a highly effective way, Stuart Allan weaves together insights from multiple strands of research across diverse disciplines. Among the themes he examines are: the role of science in science fiction, such as "Star Trek"; the problem of 'pseudo-science' in "The X-Files"; and how science is displayed in science museums. Science journalism receives particular attention, with the processes by which science is made 'newsworthy' unravelled for careful scrutiny. The book also includes individual chapters devoted to how the media portray environmental risks, HIV-AIDS, food s...

  2. Increased degradation rate of nitrososureas in media containing carbonate.

    Science.gov (United States)

    Seidegård, Janeric; Grönquist, Lena; Tuvesson, Helen; Gunnarsson, Per-Olov

    2009-01-01

    The stability of two nitrosoureas, tauromustine and lomustine, has been investigated in different media and buffers. All media tested, except Leibovitz's L-15 medium, significantly increased the degradation rate of the investigated nitrosoureas at pH 7.4. Sodium bicarbonate seems to be the cause of the observed increase of the degradation rate, since it provides the main buffering capacity of all the media except for Leibovitz's L-15 medium, which is based on phosphate buffer. Other ingredients in the media, such as amino acids, vitamins, and inorganic salts, or the ionic strength of a buffer, did not have any major effect on the degradation rate of the nitrosoureas. These results suggest that media containing carbonated buffer should be avoided when the anti-tumor effect of nitrosoureas is to be investigated in different cell cultures.

  3. Advertising media selection and planning

    NARCIS (Netherlands)

    Moorman, M.; Neijens, P.C.; Smit, E.G.; Belch, M.A.; Belch, G.E.

    2010-01-01

    Reach, frequency, and timing are key concepts in selecting TV, radio, newspapers, magazines, out-of-home, direct mail, Internet, and other media for advertising campaigns. We discuss these concepts and their role in media selection and media planning processes. We also describe media and audience

  4. Mixed-Media File Systems

    NARCIS (Netherlands)

    Bosch, H.G.P.

    1999-01-01

    This thesis addresses the problem of implementing mixed-media storage systems. In this work a mixed-media file system is defined to be a system that stores both conventional (best-effort) file data and real-time continuous-media data. Continuous-media data is usually bulky, and servers storing and

  5. Media preparation and bacteriological tools.

    Science.gov (United States)

    Elbing, Karen; Brent, Roger

    2002-08-01

    Recipes are provided in this unit for minimal liquid media, rich liquid media, solid media, top agar, and stab agar. Also included are descriptions and useful information about tools used with growth media such as inoculating loops, sterile toothpicks and spreaders.

  6. Children's media policy.

    Science.gov (United States)

    Jordan, Amy B

    2008-01-01

    Amy Jordan addresses the need to balance the media industry's potentially important contributions to the healthy development of America's children against the consequences of excessive and age-inappropriate media exposure. Much of the philosophical tension regarding how much say the government should have about media content and delivery stems from the U.S. Constitution's First Amendment protection against government interference in free speech, including commercial speech. Courts, Jordan says, have repeatedly had to weigh the rights of commercial entities to say what they please against the need to protect vulnerable citizens such as children. This balancing act is complicated even further, she says, because many government regulations apply only to broadcast television and not to non-broadcast media such as the Internet or cable television, though Congress has addressed the need to protect children's privacy online. The need to protect both free speech and children has given rise to a fluid media policy mix of federal mandates and industry self-regulation. Jordan describes the role of the three branches of the federal government in formulating and implementing media policy. She also notes the jockeying for influence in policymaking by industry lobbies, child advocacy groups, and academic researchers. The media industry itself, says Jordan, is spurred to self-regulation when public disapproval grows severe enough to raise the possibility of new government action. Jordan surveys a range of government and industry actions, from legislatively required parental monitoring tools, such as the V-Chip blocking device on television sets, to the voluntary industry ratings systems governing television, movies, and video games, to voluntary social website disclosures to outright government bans, such as indecency and child privacy information collection. She considers the success of these efforts in limiting children's exposure to damaging content and in improving parents

  7. Influence of Nitrogen Source, Thiamine, and Light on Biosynthesis of Abscisic Acid by Cercospora rosicola Passerini

    OpenAIRE

    Norman, Shirley M.; Maier, Vincent P.; Echols, Linda C.

    1981-01-01

    Abscisic acid production by Cercospora rosicola Passerini in liquid shake culture was measured with different amino acids in combination and singly as nitrogen sources and with different amounts of thiamine in the media. Production of abscisic acid was highest with aspartic acid-glutamic acid and aspartic acid-glutamic acid-serine mixtures as nitrogen sources. Single amino acids that supported the highest production of abscisic acid were asparagine and monosodium glutamate. Thiamine was impor...

  8. Aspartic acid

    Science.gov (United States)

    ... we eat. Aspartic acid is also called asparaginic acid. Aspartic acid helps every cell in the body work. It ... release Normal nervous system function Plant sources of aspartic acid include: avocado, asparagus, and molasses. Animal sources of ...

  9. DIGITALIZATION AND NEW MEDIA LANDSCAPE

    OpenAIRE

    Tadej Praprotnik

    2016-01-01

    The article presents the phenomena of new communication technologies. It exposes the role of social media (Web 2.0) and sketches some global trends within the field of new media. It further outlines basic characteristics of traditional mass communication and consumption of media products, and as a counter-part presents interactive nature of a new media and the phenomena of user-generated media contents. The main focus of the article is the process of digitalization and its influence on import...

  10. Haters Phenomena in Social Media

    OpenAIRE

    Pradipta, Angga; Lailiyah, S.Sos, M.I.Kom, Nuriyatul

    2016-01-01

    Social media is internet-basic media, functioned as interaction media room based on multimedia technology. And social media created some effects. One of the negative effects of social media is haters phenomena. Haters are a person who easily said dirty words, harass, and humiliate to others. This phenomena causes anxiety—especially in Indonesia, even the Government issued public policy and letter of regulation about this phenomena, through Paragraph 27 verse (3) IT Constitution, Paragraph 45 ...

  11. Contemplative Media Studies

    Directory of Open Access Journals (Sweden)

    Kevin Healey

    2015-08-01

    Full Text Available The psychological and socio-economic implications of digital technologies call for scholarship that engages questions about the nature of human consciousness, the construction of the self and the ethics of technical development. In this article, I outline a framework for an approach called contemplative media studies. This approach incorporates several different scholarly threads, namely: via critical political-economic media scholarship, a focus on achieving social and economic justice through policy initiatives and structural reform; via media and religious scholarship, an interest in the religious dimensions of digital culture and the role of media in shaping religious identity; and via contemplative studies, an appreciation of the applicability of contemplative principles to research methods and theory. This framework allows us to examine the spiritual ideology that drives the construction of commercial digital platforms and to ask whether alternative platforms might better catalyze human development. Anchored in a critical commitment to socio-economic justice, contemplative media studies is aimed at articulating an ethically-responsive and economically-sustainable architecture of human flourishing.

  12. Amino acids analysis during lactic acid fermentation by single strain ...

    African Journals Online (AJOL)

    L. salivarius alone showed relatively good assimilation of various amino acids that existed at only a little amounts in MRS media (Asn, Asp, Cit, Cys, Glu, His, Lys, Orn, Phe, Pro, Tyr, Arg, Ile, Leu, Met, Ser, Thr, Trp and Val), whereas Ala and Gly accumulated in L. salivarius cultures. P. acidilactici, in contrast, hydrolyzed the ...

  13. Reconstructing random media

    International Nuclear Information System (INIS)

    Yeong, C.L.; Torquato, S.

    1998-01-01

    We formulate a procedure to reconstruct the structure of general random heterogeneous media from limited morphological information by extending the methodology of Rintoul and Torquato [J. Colloid Interface Sci. 186, 467 (1997)] developed for dispersions. The procedure has the advantages that it is simple to implement and generally applicable to multidimensional, multiphase, and anisotropic structures. Furthermore, an extremely useful feature is that it can incorporate any type and number of correlation functions in order to provide as much morphological information as is necessary for accurate reconstruction. We consider a variety of one- and two-dimensional reconstructions, including periodic and random arrays of rods, various distribution of disks, Debye random media, and a Fontainebleau sandstone sample. We also use our algorithm to construct heterogeneous media from specified hypothetical correlation functions, including an exponentially damped, oscillating function as well as physically unrealizable ones. copyright 1998 The American Physical Society

  14. Representative of the Media

    International Nuclear Information System (INIS)

    Domenech, F.

    2007-01-01

    Francesc Domenech recalled that the Vandellos-I accident created a very difficult situation for the nuclear industry. During the crisis the nuclear sector decided not to participate in any media activities. Finally, the industry realised that not being open only exacerbated the credibility crisis. The closure of the Vandellos -I power plant decreased the stress and offered an opportunity for the nuclear sector to change its attitude and public relations. In Mr. Domenech's view the Vandellos-I decommissioning project is a technical challenge undertaken by society. ENRESA made great efforts to rebuild mutual trust between the nuclear industry and the media. For the first time, journalists were provided with fluid data, some of them very complex, which the media had to render more understandable for the public. Finally, Mr. Domenech observed that nowadays it is the regulator which most needs to gain credibility. (author)

  15. Foams in porous media

    Energy Technology Data Exchange (ETDEWEB)

    Marsden, S.S.

    1986-07-01

    In 1978 a literature search on selective blocking of fluid flow in porous media was done by Professor S.S. Marsden and two of his graduate students, Tom Elson and Kern Huppy. This was presented as SUPRI Report No. TR-3 entitled ''Literature Preview of the Selected Blockage of Fluids in Thermal Recovery Projects.'' Since then a lot of research on foam in porous media has been done on the SUPRI project and a great deal of new information has appeared in the literature. Therefore we believed that a new, up-to-date search should be done on foam alone, one which would be helpful to our students and perhaps of interest to others. This is a chronological survey showing the development of foam flow, blockage and use in porous media, starting with laboratory studies and eventually getting into field tests and demonstrations. It is arbitrarily divided into five-year time periods. 81 refs.

  16. Subsidizing Media Innovation

    DEFF Research Database (Denmark)

    Kammer, Aske; Hobel, Emil

    When the Danish Parliament revised the media-subsidy framework in 2013/2014, one of the new initiatives was the introduction of a pool of funding earmarked to establishing and developing new news media – the so-called “innovation fund”. So, as the news industry struggles to keep journalism a viable...... and economically sustainable activity, the institutionalization of financial support for media innovation constitute one way for policy makers to bring (parts of) the journalistic environment up-to-date with the digital age, thereby improving the conditions for an informed citizenry in the future (Kammer...... scrutinizes the practical administration of the innovation fund in the first two years of its existence, analyzing all applications for innovation subsidies in 2014 and 2015 as well as all acceptance and rejection letters. With this empirical material and a combination of quantitative and qualitative...

  17. Media and metamedia management

    CERN Document Server

    Araújo, Xosé; Fernández, Valentín; García, Xosé

    2017-01-01

    Media and Metamedia Management has contributions from seven prestigious experts, who offer their expertise and the view from their vantage point on communication, journalism, advertising, audiovisual, and corporate, political, and digital communication, paying special attention to the role of new technologies, the Internet and social networks, also from an ethics and legal dimension. A total of 118 authors belonging to 31 universities from Spain, Portugal, England and Ecuador have contributed to this book edited, coordinated and introduced by professors Francisco Campos-Freire and Xosé López-García, from the University of Santiago de Compostela, José Rúas-Araújo, from the University of Vigo, and Valentín A. Martínez-Fernández, from the University of A Coruña. Readers may also enjoy 66 articles, grouped into diverse chapters, on Journalism and cyberjournalism, audiovisual sector and media economy, corporate and institutional communication, and new media and metamedia.

  18. Media and Multiplicity

    DEFF Research Database (Denmark)

    Blaagaard, Bolette

    2010-01-01

    In the past few years continental Europe has experienced a resurgence of right-wing party politics, nationalism and xenophobia. In this nationalist revival the media and advanced communications technologies have played a significant role, as evidenced by the debates following cases...... such as the Danish cartoon controversy, and Dutch politician Geert Wilders’s film, Fitna. Simultaneously, however, the media is more diverse and rhizomatic than ever and offers potential for cosmopolitanism, transnational ethical relations as well as radical anti-racist and anti-fascist interventions. This article...... explores the tensions within the relation between journalistic practice and the construction of the idea of the nation and the multiplicity of media and cultures which inhabit the spheres of journalism and nation....

  19. Enterprise Social Media

    DEFF Research Database (Denmark)

    Khajeheian, Datis

    2018-01-01

    This article reports an ethnographic research on effect of enterprise social media on communication of members in entrepreneurial teams. The researcher acted as an entrepreneur and as a team member in two entrepreneurial projects to observe the communication of team members within the enterprise...... social media. In addition to observation, he conducted some interviews with team members to collect supplementary data. A theoretical framework developed from an array of three metaphors: leaky pipe, echo chamber and social lubricant, and four organizational learning processes: social capital, boundary...... work, attention allocation and social analytics. By the interpretation of the collected data, a new metaphor of “living room” was proposed. This metaphor suggests that enterprise social media provide a space for interaction of internal-external people similar to what home members and guests do...

  20. Media for Reflection

    DEFF Research Database (Denmark)

    Knudsen, Morten

    2016-01-01

    This article develops the concept media for reflection in the interest of conceptualizing the interpretative frames that enable and limit reflection in management and leadership education. The concept ‘media for reflection’ allows us to conceptualize the social and cultural mediation of reflection...... without reducing reflection to an effect of the social structures and cultural norms in which it is embedded. Based on the developed theoretical framework, this article analyses how a renaissance ‘mirror for princes’ and contemporary research-based management education mediate reflection. The content...... of the mediations is analysed as well as the societal and organizational background. Furthermore, the means by which the two media enable and limit reflection in different ways is compared. Finally, the article discusses possible implications of the analysis in terms of management and leadership education....

  1. Boiling in porous media

    International Nuclear Information System (INIS)

    1998-01-01

    This conference day of the French society of thermal engineers was devoted to the analysis of heat transfers and fluid flows during boiling phenomena in porous media. This book of proceedings comprises 8 communications entitled: 'boiling in porous medium: effect of natural convection in the liquid zone'; 'numerical modeling of boiling in porous media using a 'dual-fluid' approach: asymmetrical characteristic of the phenomenon'; 'boiling during fluid flow in an induction heated porous column'; 'cooling of corium fragment beds during a severe accident. State of the art and the SILFIDE experimental project'; 'state of knowledge about the cooling of a particulates bed during a reactor accident'; 'mass transfer analysis inside a concrete slab during fire resistance tests'; 'heat transfers and boiling in porous media. Experimental analysis and modeling'; 'concrete in accidental situation - influence of boundary conditions (thermal, hydric) - case studies'. (J.S.)

  2. Media and (Demythologization

    Directory of Open Access Journals (Sweden)

    Damir Kukić

    2017-05-01

    Full Text Available The media participate in the creation of new myths in modern society. Some of these myths have been created in the entertainment industry as well as in celebrity culture. The new media stars, regardless of the period of their popularity, function as part of the star strategy. However, as an element of the cultural matrix, the media also participate in the process of creating new political myths. In ethno-national and closed societies the myths function as a fundamental component for the unification of a nation and the definition of its identity. In such a context, their role is to create an image of the world, by shaping images from the past, in which people from other cultures and nations are presented as enemies.

  3. Media Challenging Status Quo

    DEFF Research Database (Denmark)

    Sandvik, Kjetil

    and Libya creating headlines like “the Facebook revolution”. On the other hand, several scholars argue that it is naive to believe that social media in themselves create change: they may at the best facilitate already existing social and political movements (Downing 2008, Christakis & Fowler 2010...... and communication research is currently engaging in a longer and deeper process of examining and assessing the cultural consequences of networked communication. One present challenge is to understand digital media and networked communication at the intersection of established and countercultural, utopian......Digital media and especially so-called ‘social media’ have on the one hand been ascribed the power to change societies and empower democratic movements following the thoughts of e.g. Rheingold (2004), recently fueled by the democratic uprising in Arabic countries such as Egypt, Tunisia, Iran...

  4. Open Media Training Session

    CERN Multimedia

    CERN. Geneva; Marchant, Nadia

    2010-01-01

    Have you ever wondered how the media work and why some topics make it into the news and other don't? Would you like to know how to (and how not to) give an interview to a journalist? With the LHC preparing for first collisions at high energies, the world's media are again turning their attention to CERN. We're all likely to be called upon to explain what is happening at CERN to media, friends and neighbours. The seminar will be given by BBC television news journalists Liz Pike and Nadia Marchant, and will deal with the kind of questions we're likely to be confronted with through the restart period. Follow the webcast: http://webcast.cern.ch/

  5. Internet and Cross Media Productions

    DEFF Research Database (Denmark)

    Petersen, Anja Bechmann

    2006-01-01

    , the Internet continues to play a minor role when compared to older media. The content of the cross media concepts and organizations' history are crucial elements in deciding the priority and use of platforms. Methodologically, the article approaches cross media and the roles of the Internet on a micro......Convergence is one of the hot topics in Internet studies. Recently, however, media organizations have turned their focus to cross media communication. Media organizations are interested in optimizing communication across platforms such as TV, radio, websites, mobile telephones and newspapers....... The aim of this article is to examine the roles of the Internet when emphasis is put on cross media rather than convergence. This article proposes not one unidirectional convergent tendency but manifold roles of the Internet in cross media communication. Inside the media organizations, however...

  6. Children, Adolescents, and the Media.

    Science.gov (United States)

    2013-11-01

    Media, from television to the "new media" (including cell phones, iPads, and social media), are a dominant force in children's lives. Although television is still the predominant medium for children and adolescents, new technologies are increasingly popular. The American Academy of Pediatrics continues to be concerned by evidence about the potential harmful effects of media messages and images; however, important positive and prosocial effects of media use should also be recognized. Pediatricians are encouraged to take a media history and ask 2 media questions at every well-child visit: How much recreational screen time does your child or teenager consume daily? Is there a television set or Internet-connected device in the child's bedroom? Parents are encouraged to establish a family home use plan for all media. Media influences on children and teenagers should be recognized by schools, policymakers, product advertisers, and entertainment producers. Copyright © 2013 by the American Academy of Pediatrics.

  7. Using the media.

    Science.gov (United States)

    1994-01-01

    To use the mass media (newspaper, radio, and TV) to reach a large audience with information about AIDS, it is important to choose the media outlets carefully, since they use information that satisfies their audience in content and style. For example, radio, TV, or videos are best to reach illiterate groups. Ways to approach each sector of the written and electronic media include press releases, news conferences, information kits, and personal contacts. Letters to the editor and offers of submitting articles for publication are additional ways to approach newspapers. Audio- or videocassettes with interviews or images conveying HIV/AIDS prevention messages can be submitted to TV and radio stations. It is important to present the information attractively to gain the journalists' attention. News releases should include sources of information and a contact name. It is important to inform the mass media of successes revolving around AIDS prevention, emphasizing local successes. One should identify what media slots have the most influence. For example, a medical officer in Chiang Mai, Thailand, notes that popular disc jockeys have more influence than do government information broadcasts. It is best to promote facts that probably will increase support for AIDS prevention campaigns. If possible, groups should seek free space or air time for AIDS prevention messages. AIDS prevention messages should not use fear because it does not promote safer sexual behavior. Instead, they should link condom use with a sense of independence, responsibility, and being fashionable. Leaflets, posters, videotapes, slides, displays, slogans, audiocassettes, T-shirts, stickers, and other activities or products reinforce the effectiveness of media campaigns. Interviews with or feature articles and programs about people infected or affected by HIV/AIDS chip away at the belief that "AIDS could never happen to me."

  8. Composition of single-step media used for human embryo culture.

    Science.gov (United States)

    Morbeck, Dean E; Baumann, Nikola A; Oglesbee, Devin

    2017-04-01

    To determine compositions of commercial single-step culture media and test with a murine model whether differences in composition are biologically relevant. Experimental laboratory study. University-based laboratory. Inbred female mice were superovulated and mated with outbred male mice. Amino acid, organic acid, and ions content were determined for single-step culture media: CSC, Global, G-TL, and 1-Step. To determine whether differences in composition of these media are biologically relevant, mouse one-cell embryos were cultured for 96 hours in each culture media at 5% and 20% oxygen in a time-lapse incubator. Compositions of four culture media were analyzed for concentrations of 30 amino acids, organic acids, and ions. Blastocysts at 96 hours of culture and cell cycle timings were calculated, and experiments were repeated in triplicate. Of the more than 30 analytes, concentrations of glucose, lactate, pyruvate, amino acids, phosphate, calcium, and magnesium varied in concentrations. Mouse embryos were differentially affected by oxygen in G-TL and 1-Step. Four single-step culture media have compositions that vary notably in pyruvate, lactate, and amino acids. Blastocyst development was affected by culture media and its interaction with oxygen concentration. Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  9. Mobile Media Photography

    DEFF Research Database (Denmark)

    Svabo, Connie; Shanks, Michael

    2013-01-01

    Mobile media photography marks a shift in orientation from the image towards photography as a mode of engagement. This leads is to explore the processes of experience and documentation that mobile media help to constitute. We unfold two aspects of the process of photography: photography as temporal......, archaeological engagement, and photography as spatial, geographical engagement. Finally, as a closing perspective we point out that vernacular photography may be read as an intersection between a personal means of expression and corporate financial interest....

  10. Acute otitis media.

    Science.gov (United States)

    Dickson, Gretchen

    2014-03-01

    One in 4 children will have at least 1 episode of acute otitis media (AOM) by age 10 years. AOM results from infection of fluid that has become trapped in the middle ear. The bacteria that most often cause AOM are Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Differentiating AOM from otitis media with effusion (OME) is a critical skill for physicians, as accurate diagnosis will guide appropriate treatment of these conditions. Although fluid is present in the middle ear in both conditions, the fluid is not infected in OME as is seen in AOM patients. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Strategy and New Media

    DEFF Research Database (Denmark)

    Plesner, Ursula; Gulbrandsen, Ib Tunby

    2015-01-01

    Despite current attention to the materiality of organizations and the performative role of tools, devices, artefacts and objects in processes of strategy-making, the impact of new media has not been thoroughly conceptualized in the strategy literature. We argue that new media challenge core...... assumptions in strategy about control, boundaries and choice. To understand their constitutive effects and the implications for strategy-making, it is necessary to develop a research agenda oriented towards understanding technological affordances – but not only in local practices. Due to vital characteristics...

  12. Media and Influence

    Science.gov (United States)

    Bennett, William H.

    The public information media provides information on current events (news), entertainment (programming), and opinions offered by trusted public sources (e.g., business, academic or religious spokespersons, journalists, and government officials). Consequently, it is a major force in shaping a populace's attitudes toward significant social issues and of great interest to intervention planners. The chapter attempts to provide modelers and intervention analysts alike with sufficient understanding of media mechanisms and current research that they can begin contributing to, and benefiting from this important area of study.

  13. Multisided Media Markets

    DEFF Research Database (Denmark)

    Lindstädt, Nadine

    Media markets recently have been identified as multisided markets. The application of the theory of multisided markets provides a better understanding of such markets. It enriched the hitherto economic approach and led to new insights and perspectives especially for the antitrust authorities when...... evaluating competition constraints and mergers. This paper reviews the theory of multisided markets and subsequently applies it to media markets. Finally the paper draws attention to the new perspectives and insights the theory provides but also brings open research questions to light....

  14. Smartphones as locative media

    CERN Document Server

    Frith, Jordan

    2015-01-01

    Smartphone adoption has surpassed 50% of the population in more than 15 countries, and there are now more than one million mobile applications people can download to their phones. Many of these applications take advantage of smartphones as locative media, which is what allows smartphones to be located in physical space. Applications that take advantage of people's location are called location-based services, and they are the focus of this book. Smartphones as locative media raise important questions about how we understand the complicated relationship between the Internet and physical space

  15. Hypertextuality and Social Media

    DEFF Research Database (Denmark)

    Albu, Oana Brindusa; Etter, Michael

    2016-01-01

    Texts and conversations are central to the constitution of organizations. Through the use of social media technologies, organizational members and nonorganizational members alike have the capacity to author organizational texts that co-constitute an organization as an entity with a specific...... identity in a situational space and time. The implications of this ability are underexplored. This study focused on how two organizations used the social media technology Twitter to interact with their constituents. The article adopts communication-centered and sociomateriality perspectives to illustrate...

  16. HTML5 Media

    CERN Document Server

    Powers, Shelley

    2011-01-01

    If you're a web developer or designer familiar with CSS and JavaScript, this tightly focused introduction shows you how to add HTML5 media elements to your web pages, and how to provide custom controls for letting web visitors interact with the content. You'll also learn how to provide subtitles and captions, using file formats that work in browsers now. This book includes code samples and downloadable examples to help you take full advantage of audio and video in your web pages. Ensure your audio or video works in all browsers that support HTML5 media elementsLearn about widely supported me

  17. Interpolymer complexes based on the core/shell micelles. Interaction of polystyrene-block-poly(methacrylic acid) micelles with linear poly(2-vinylpyridine) in 1,4-dioxane water mixtures and in aqueous media

    Czech Academy of Sciences Publication Activity Database

    Matějíček, P.; Uchman, M.; Lokajová, J.; Štěpánek, M.; Procházka, K.; Špírková, Milena

    2007-01-01

    Roč. 111, č. 29 (2007), s. 8394-8401 ISSN 1520-6106. [International Symposium on Polyelectrolytes /6./. Dresden, 04.09.2006-08.09.2006] R&D Projects: GA ČR GA203/04/0490; GA AV ČR IAA400500505 Institutional research plan: CEZ:AV0Z40500505 Keywords : polystyrene-block-poly(methacrylic acid) * poly(2-vinylpyridine) * core/shell micelles * light scattering * atomic force microscopy Subject RIV: CD - Macromolecular Chemistry Impact factor: 4.086, year: 2007

  18. Mediatization Theory and Digital Media

    DEFF Research Database (Denmark)

    Finnemann, Niels Ole

    2011-01-01

    In the 20th century, the term "media logic" was introduced to denote the influence of independent mass media on political systems and other institutions. In recent years the idea has been reworked and labelled "mediatization" to widen the framework by including new media and new areas of applicat......In the 20th century, the term "media logic" was introduced to denote the influence of independent mass media on political systems and other institutions. In recent years the idea has been reworked and labelled "mediatization" to widen the framework by including new media and new areas...

  19. Temporal patterning of the potential induced by localized corrosion of iron passivity in acid media. Growth and breakdown of the oxide film described in terms of a point defect model.

    Science.gov (United States)

    Sazou, Dimitra; Pavlidou, Maria; Pagitsas, Michael

    2009-10-21

    This work analyses the nature of temporal patterning of the anodic potential induced by chlorides during polarization of iron under current-controlled conditions in acid solutions. It is shown that potential oscillations emerged as a result of the local chloride attack of a thin oxide layer, which covers the iron surface in its passive state. The mechanism by which both the local oxide breakdown and the subsequent localized active dissolution (pitting) occur is explained by considering a point defect model (PDM) developed to describe the oxide growth and breakdown. According to the PDM, chlorides occupy oxygen vacancies resulting in the inhibition of oxide growth and autocatalytic generation of cation vacancies that destabilize the oxide layer. Simultaneous transformation of the outer surface of the inner oxide layer to non-adherent ferrous chloride or oxo-chloride species leads to a further thinning of the oxide layer and its lifting-on from the iron surface. The process repeats again yielding sustained oscillations of the anodic potential. Analysis of the oscillatory response obtained under current-controlled conditions as a function of either the current or the time allows the suggestion of a set of alternate diagnostic criteria, which might be used to characterize localized corrosion of iron in acid solutions.

  20. More Media, More People—On Social & Multimodal Media Intelligence

    OpenAIRE

    Degerstedt, Lars; Pelle, Snickars

    2017-01-01

    The purpose of this article is to address some challenges facing media intelligence in general, and competitive intelligence in particular within an altered information landscape. To understand this new situation, the notion of social and multimodal media intelligence are introduced. With cases taken primarily from the Swedish media intelligence sector, we argue that data driven media intelligence today needs to pay increasing attention to new forms of (A.) crowd-oriented and (B.) multimedia-...

  1. Homogenization of discrete media

    Energy Technology Data Exchange (ETDEWEB)

    Pradel, F.; Sab, K. [CERAM-ENPC, Marne-la-Vallee (France)

    1998-11-01

    Material such as granular media, beam assembly are easily seen as discrete media. They look like geometrical points linked together thanks to energetic expressions. Our purpose is to extend discrete kinematics to the one of an equivalent continuous material. First we explain how we build the localisation tool for periodic materials according to estimated continuum medium type (classical Cauchy, and Cosserat media). Once the bridge built between discrete and continuum media, we exhibit its application over two bidimensional beam assembly structures : the honey comb and a structural reinforced variation. The new behavior is then applied for the simple plan shear problem in a Cosserat continuum and compared with the real discrete solution. By the mean of this example, we establish the agreement of our new model with real structures. The exposed method has a longer range than mechanics and can be applied to every discrete problems like electromagnetism in which relationship between geometrical points can be summed up by an energetic function. (orig.) 7 refs.

  2. Dynamics of Media Attention

    NARCIS (Netherlands)

    Traag, V.A.; Reinanda, R.; Hicks, J.; van Klinken, G.; Aziz-Alaoui, M.A.; Bertelle, C.; Liu, X.; Olivier, D.

    2014-01-01

    Studies of human attention dynamics analyses how attention is focused on specific topics, issues or people. In online social media, there are clear signs of exogenous shocks, bursty dynamics, and an exponential or powerlaw lifetime distribution. We here analyse the attention dynamics of traditional

  3. Handboek Nieuwe Media

    NARCIS (Netherlands)

    Tom Bakker; Dr. Piet Bakker

    2011-01-01

    Voor mensen die beroepshalve met communicatie en informatie te maken hebben, is het belangrijk om op de hoogte te zijn van de meest actuele en relevante ontwikkelingen op dat terrein. Het gaat hierbij niet alleen over social media of web 2.0 - ook het zoeken, beheren en publiceren van informatie is

  4. Cyberbullying via Social Media

    Science.gov (United States)

    Whittaker, Elizabeth; Kowalski, Robin M.

    2015-01-01

    Recent years have witnessed a surge of research on cyberbullying. In this article, three studies examined prevalence rates of cyberbullying among college-age students, venues through which cyberbullying occurs, with a particular focus on social media, and perceptions of cyberbullying as a function of features of the target (e.g., peer, celebrity,…

  5. Islam and Media Representations

    Directory of Open Access Journals (Sweden)

    Mohamed Bensalah

    2006-04-01

    Full Text Available For the author of this article, the media’s treatment of Islam has raised numerous polymorphous questions and debates. Reactivated by the great scares of current events, the issue, though an ancient one, calls many things into question. By way of introduction, the author tries to analyse the complex processes of elaboration and perception of the representations that have prevailed during the past century. In referring to the semantic decoding of the abundant colonial literature and iconography, the author strives to translate the extreme xenophobic tensions and the identity crystallisations associated with the current media orchestration of Islam, both in theWest and the East. He then evokes the excesses of the media that are found at the origin of many amalgams wisely maintained between Islam, Islamism and Islamic terrorism, underscoring their duplicity and their willingness to put themselves, consciously, in service to deceivers and directors of awareness, who are very active at the heart of the politico-media sphere. After levelling a severe accusation against the harmful drifts of the media, especially in times of crisis and war, the author concludes by asserting that these tools of communication, once they are freed of their masks and invective apparatuses, can be re-appropriated by new words and bya true communication between peoples and cultures.

  6. Media challenging capitalism

    DEFF Research Database (Denmark)

    Sandvik, Kjetil

    Digital media and especially so-called ‘social media’ have on the one hand been ascribed the power to change societies and empower democratic movements following the thoughts of e.g. Rheingold (2004), recently fueled by the democratic uprising in Arabic countries such as Egypt, Tunisia, Iran and ...

  7. Femicide in media

    Directory of Open Access Journals (Sweden)

    Mršević Zorica

    2014-01-01

    Full Text Available Media in Serbia explain femicide usually as caused by poverty and alcoholism. This style is gender blind and socially stereotyped because of neglected gender aspects of male violence against women. Particular problem is lack of problematizing obvious social “permission” of male violence. Femicide is regularly presented as an incident, allegedly impossible for anticipation rather than tragic epilogue of long lasting male violence against women which as such exists as a part of traditional gender social relations and roles. Media overlook that alcohol and poverty may only contribute to intensification of already existing, widely accepted domination of men and subordination of women. Media reports as a rule didn’t enter deeper into problems of institutional and social context in which is perpetrated long lasting violence as prefacing femicide. Media also never criticize the social behavior of neighbors, relatives and all others informed on the domestic violence, but rather avoid „mixing“into privacy matters. Thus violence escalates without barriers, eventually developed in femicide, murder a woman, victim of this, decades long lasting violence.

  8. European media law

    NARCIS (Netherlands)

    Castendyk, O.; Dommering, E.; Scheuer, A.

    2008-01-01

    European Union legislation concerning electronic communications media is firmly established as an essential part of the law in the field in Europe. From relevant provisions of the European Convention of Human Rights and the EC Treaty to numerous directives, the most recent being the Audiovisual

  9. Media for Enterobacteriaceae

    NARCIS (Netherlands)

    Mossel, D.A.A.

    1985-01-01

    The ‘rag-bag character of ‘coli-aerogenes’ bacteria used originally as markers for process failure has prompted their substitution by the taxonomically accurately delineated group of Enterobacteriaceae. Media previously used for the detection or enumeration of the coli-aerogenes group can be adapted

  10. Media: A Pocket Guide.

    Science.gov (United States)

    Arrasjid, Harun; Arrasjid, Dorine Audrey

    An attempt has been made to provide a concise but comprehensive guide to instructional media for instructors, students, and teachers. Topics covered include audio learning systems, overhead projection, opaque projection, slide and filmstrip projection, projection surfaces, chalkboards and markboards, graphics, models, duplicating, motion pictures,…

  11. Contrast media: future aspects

    International Nuclear Information System (INIS)

    Weinmann, H.J.; Platzek, J.; Schirmer, H.; Pietsch, H.; Carretero, J.; Harto, J.; Medina, J.; Riefke, B.; Martin, J.

    2005-01-01

    In spite of the dramatic development in CT, there was no major breakthrough in the iodinated contrast media development. New agents based on hybrid between MRI and CT compounds may be a new innovative alternative. This new approach may also open new indications such as radiotherapy. (orig.)

  12. Corruption in the Media.

    NARCIS (Netherlands)

    Spence, E.H.

    2009-01-01

    Using a general model of corruption that explains and accounts for corruption across different corporate and professional activities, the paper will examine how certain practices in the media, especially in areas where journalism, advertising and public relations regularly intersect and converge,

  13. Social Media Empowerment (III)

    NARCIS (Netherlands)

    A. Cox

    2011-01-01

    full text via link. Synovate heeft de afgelopen twee jaar onderzoek verricht op dit terrein. Anita Cox, Emile Rikken en Stephan van Velthoven zetten op basis daarvan zaken op een rij in een serie van 5 artikelen, hier op Molblog te lezen. In dit artikel staat brand-building via social media

  14. Big Data, Small Media

    Directory of Open Access Journals (Sweden)

    Grant Bollmer

    2014-08-01

    Andrew Dubber Radio in the Digital Age Polity, Cambridge, 2013   Charles Ess Digital Media Ethics, Second Edition Polity, Cambridge, 2014   Graeme Kirkpatrick Computer Games and the Social Imaginary Polity, Cambridge, 2013   Dhiraj Murthy Twitter: Social Communication in the Twitter Age Polity, Cambrige, 2013   Jill Walker Rettberg Blogging, Second Edition Polity, Cambridge, 2014

  15. Digital media ethics

    DEFF Research Database (Denmark)

    Ess, Charles

    Designed as both a teaching text and reader for students and faculty across diverse disciplines, the book provides an "ethical toolkit" - an introduction to prevailing ethical frameworks - and shows their application to both general issues and specific case-studies in digital media (privacy...

  16. Expanding Media Reach

    Centers for Disease Control (CDC) Podcasts

    2007-11-01

    In this podcast, two nurses serving a Chinese American community show how they have used local ethnic media to communicate health messages.  Created: 11/1/2007 by National Diabetes Education Program (NDEP), a joint program of the Centers for Disease Control and Prevention and the National Institutes of Health.   Date Released: 11/11/2007.

  17. Using Media Effectively.

    Science.gov (United States)

    Danzer, Gerald A.; Newman, Mark

    1992-01-01

    Recommends that media presentations can be used effectively in the history classroom as images of reality. Suggests films and television programs and documentaries that can be utilized to show how movies play a role in shaping opinion and changing perceptions. (DK)

  18. The Indian Media Scenario.

    Science.gov (United States)

    Eapen, K. E.

    As background information for a discussion of India's communication system and its potential for social change, this paper briefly describes the country's physical characteristics, some of its cultural heritage and demographics, and the development of its education and railways. After a discussion of the folk media (traditional changes) of…

  19. Electrokinetics in porous media

    NARCIS (Netherlands)

    Luong, D.T.

    2014-01-01

    This thesis presents the PhD research on electrokinetics in porous media. Electrokinetic phenomena are induced by the relative motion between a fluid and a solid surface and are directly related to the existence of an electric double layer between the fluid and the solid grain surface.

  20. Need for Orientation, Media Uses and Gratifications, and Media Effects.

    Science.gov (United States)

    Weaver, David

    In order to study the influence of need for orientation and media gratifications on media use and media effects in political communication, two previous surveys were studied to compare the causal modeling approach and the contingent conditions approach. In the first study, 339 personal interviews were conducted with registered voters during a…

  1. Applying East Asian Media Diplomacy Models to African Media: A ...

    African Journals Online (AJOL)

    The last two decades have seen the extensive expansion of South African and Nigerian media on the African continent. However, while the link between media and diplomacy, and the role of media in visualising the state for foreign audiences have received a lot of scholarly attention internationally, relatively little work has ...

  2. Media Culture and Media Education in Modern School

    Science.gov (United States)

    Tolic, Mirela

    2011-01-01

    Culture is no longer conceivable without the media and/or new phenomena called. "Cyber" culture. The article discusses issues in what respect the different media, like TV, film and Internet are with different cultures, how it changes everyday life under influence of various forms of sophisticated communications media and what…

  3. Editorial: Pedagogical Media Ecologies

    Directory of Open Access Journals (Sweden)

    Dorothee M. Meister

    2014-07-01

    Full Text Available From educational gaming through portable e-readers to cell phones, media are interpenetrating educational spaces and activities. Accordingly, understanding media in environmental or ecological terms has become increasingly important for education internationally. In North America, for example, the centenary of McLuhan’s birth has focused attention on approaches to media – whether oral, textual, electronic or digital– as a kind of environment in which education takes place. In parts of Europe, the so-called mediatic turn – following on the linguistic and iconic turns – has similarly emphasized the role of media as a condition for the possibility of educational activities and programs. With a few exceptions1 the papers in this special issue were first presented at the conference «Educational Media Ecologies: International Perspectives» which took place at the University of Paderborn, Germany, on March 27–28, 2012.2 The event was an interdisciplinary and transatlantic endeavor to bring together a wide range of perspectives on various issues relevant to educational media ecologies,3 and on related debates on mediation, medialization, mediatization, and mediality.4 The purpose of this volume, like the conference, is to foster and deepen international dialogue in the area of educational media. Areas of research and scholarship relevant to this dialogue include educational media, media literacy, educational philosophy, and media and cultural studies. The contributions, described below, put conceptual issues as well as social practices and applications at the center of the debate. Klaus Rummler opens the issue by clarifying the concept of ecology itself. Referencing a range of work over the past 50 years, Rummler describes how ecological models have been cast in sociological, semiotic, cultural, mediatic and other terms, and he explains the implications of these various perspectives for the study of educational contexts. Rummler also

  4. DISKURSUS ISLAM DALAM KONSTRUKSI MEDIA

    Directory of Open Access Journals (Sweden)

    Muhammad Fahmi

    2015-12-01

    Full Text Available This paper aims to examine how the secular media in Surakarta represent Islam in the case of Charlie Hebdo. Therefore, this study used discourse analysis of Theo van Leeuwen focusing on how the subject or actor of the show in the media. This study concluded that the media represent Islam not only with “Western ideology” through idioms such as radical Islamist militants and terrorists, but also with "Islamic ideology". It is done through the construction of Islam as a religion of moderation and delegitimize Charlie Hebdo as magazine satyr abusing freedom. Various strategies are used ranging from strategy passivation to interdetermination. In this case, there are two poles of attraction in both media, namely the Western and Islamic ideology. If both media are quoting from Western sources, the Western ideology dominates the media narrative. Conversely, when both media used Islamic sources, the influence of Islamic ideology dominates the narrative of both media.

  5. Media independence and dividend policy

    DEFF Research Database (Denmark)

    Farooq, Omar; Dandoune, Salma

    2012-01-01

    independence and dividend policies in emerging markets. Using a dataset from twenty three emerging markets, we show a significantly negative relationship between dividend policies (payout ratio and decision to pay dividend) and media independence. We argue that independent media reduces information asymmetries...... for stock market participants. Consequently, stock market participants in emerging markets with more independent media do not demand as high and as much dividends as their counterparts in emerging markets with less independent media. We also show that press independence is more important in defining......Can media pressurize managers to disgorge excess cash to shareholders? Do firms in countries with more independent media follow different dividend policies than firms with less independent media? This paper seeks to answer these questions and aims to document the relationship between media...

  6. Media life of the young

    DEFF Research Database (Denmark)

    Westlund, Oscar; Bjur, Jakob

    2014-01-01

    This is a thorough investigation into contemporary young people and their media life. The article conceptualizes a typology of media life, drawing on a theoretical body involving the sociology of generations, life course research, media life and individualization. This empirically derived typology...... makes a strong instrument for an understanding of the media life of the young, furnishing insights into how they have constructed their use of media. The investigation is based on a robust national survey with Swedes born 1994–2001, conducted in 2010, and focusing on four media: television, gaming......, the Internet and mobile devices. Two of the findings are particularly surprising. Firstly, the results reveal that the young generally lead heterogeneous media lives, varying with age and sex. Secondly, although some young people literarily live their life in media, there are also de facto young who live...

  7. Study of 3-Ethylamino-but-2-enoic acid phenylamide as a new ligand for preconcentration of lanthanides from aqueous media by liquid-liquid extraction prior to ICP-MS analysis.

    Science.gov (United States)

    Varbanova, Evelina K; Angelov, Plamen A; Stefanova, Violeta M

    2016-11-01

    In the present work the potential of a new ligand 3-Ethylamino-but-2-enoic acid phenylamide (representing the class of enaminones) for selective preconcentration of lanthanides (La, Ce, Eu, Gd and Er) from aqueous medium is examined. Liquid-liquid extraction parameters, such as pH of the water phase, type and volume of organic solvent, quantity of ligand and reaction time are optimized on model solutions. Recovery of lanthanides by re-extraction with nitric acid makes the LLE procedure compatible with Inductively Coupled Plasma Mass Spectrometry. Spectral and non-spectral interferences are studied. Two isotopes per element are measured (with exception of La) for dynamic evaluation of the potential risk of spectral interference in variable real samples. The selectivity of complex formation reaction towards concomitant alkali and alkali-earth elements eliminates the interferences from sample matrix. Subjecting the standards to the optimized extraction procedure in combination with Re as internal standard is recommended as calibration strategy. The accuracy of developed method is approved by analysis of CRM Bush branches and leaves (NCS DC 73348) and recovery of spiked water and plant samples. The method's limits of detection for both studied objects are in the ranges from 0.2 ((158)Gd) to 3.7 ((139)La) ngl(-1) and 0.02 ((158)Gd) to 0.37((139)La) ngg(-1) for waters and plants respectively. The studied compound is an effective new ligand for preconcentration/separation of lanthanides from aqueous medium by LLE and subsequent determination by ICP-MS. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Competition and Commercial Media Bias

    OpenAIRE

    Blasco, Andrea; Sobbrio, Francesco

    2011-01-01

    This paper reviews the empirical evidence on commercial media bias (i.e., advertisers influence over media accuracy) and then introduces a simple model to summarize the main elements of the theoretical literature. The analysis provides three main policy insights for media regulators: i) Media regulators should target their monitoring efforts towards news contents upon which advertisers are likely to share similar preferences; ii) In advertising industries characterized by high correlation in ...

  9. Social media as leisure culture

    OpenAIRE

    Albrechtslund, Anne-Mette Bech; Albrechtslund, Anders

    2014-01-01

    The purpose of this paper is to situate the everyday use of social media in the broader cultural practice of leisure. Whereas the use of social media has many different aims and contexts, our main idea is to emphasize how social media practices associated with leisure and playfulness rather than functionality and tasks — therefore seemingly “useless” in a strictly utilitarian sense — are practices which are meaningful. We point to certain dynamics in social media practices which we connect to...

  10. Social Media and the Army

    Science.gov (United States)

    2010-04-01

    interaction and create dialogue at the click of a mouse. Social media has had an undeniable effect on the way we live, work, and communicate... benefits of social media applications, a bevy of opportunities present themselves when accurately strategized. Planning might include— Your Strategy...in establishing a positive social media presence. Trust enables leaders to open up their organizations to social media , and training provides

  11. Documentary Media and Religious Communities

    Directory of Open Access Journals (Sweden)

    Marie-Therese Mäder

    2015-11-01

    Full Text Available The article considers four spaces where media processes involve religious communities and agents: the spaces of production, of representation, of media communication, and of distribution network and institutional framework for circulation. These three spaces systematise the research question posed to the specific source. Furthermore the concept documentary media as viewed from a semio-pragmatic perspective is introduced. Discussion of the commercial series I’m a Mormon shows how different modes define documentary media according to the three spaces.

  12. Going Public on Social Media

    Directory of Open Access Journals (Sweden)

    Greg Elmer

    2015-04-01

    Full Text Available This brief essay questions the disconnect between the financial goals of social media properties and the concerns of privacy advocates and other new media critics. It is argued that critics of social media often fail to recognize the financial imperative of social media companies, one that requires users to divulge and publicize ever more granular aspects of their daily lives, thoughts, and feelings.

  13. [Media for 21st century--towards human communication media].

    Science.gov (United States)

    Harashima, H

    2000-05-01

    Today, with the approach of the 21st century, attention is focused on multi-media communications combining computer, visual and audio technologies. This article discusses the communication media target and the technological problems constituting the nucleus of multi-media. The communication media is becoming an environment from which no one can escape. Since the media has such a great power, what is needed now is not to predict the future technologies, but to estimate the future world and take to responsibility for future environments.

  14. TU Delft en online media

    NARCIS (Netherlands)

    Speekenbrink, R.J.H.

    2013-01-01

    Dit boek behandelt een visie op online media bij Nederlandse universiteiten. Daarbij beperk ik me tot die aspecten waarin online communicatie en/of online marketing een rol speelt. Dit boek behandelt niet de onderwijsgerelateerde aspecten van online media. Elektronische leeromgevingen, sociale media

  15. Social media and activist communication

    NARCIS (Netherlands)

    Poell, T.; van Dijck, J.; Atton, C.

    2015-01-01

    While the rise of social media has made activists much less dependent on television and mainstream newspapers, this certainly does not mean that activists have more control over the media environments in which they operate. Media power has neither been transferred to the public, nor to activists for

  16. The Media and Transformative Learning.

    Science.gov (United States)

    Palazon, Maria

    The media constitute important sources and resources for development of critical thought about the media themselves and the reality they represent. The first theories of the media were based on the concept of unidirectional communication. Later, factors such as the increasing interest in audiences and development of cultural studies caused…

  17. Media Competition and Electoral Politics

    NARCIS (Netherlands)

    Piolatto, A.; Schuett, F.

    2013-01-01

    Abstract: We build a framework linking competition in the media market to political participation, media slant, and selection of politicians. Media outlets report on the ability of candidates running for office and compete for audience through their choice of slant. Citizens derive utility from

  18. Do the Media Undermine Democracy?

    Science.gov (United States)

    Dorman, William A.

    This paper considers political reasoning within a democracy and how mass media may affect that process, as well as how the perspective and method of critical thinking may be brought to bear on the subject of media and politics. Specifically, the paper (1) discusses some ways in which the mass media may affect political reasoning; (2) offers a…

  19. Media Literacy Is the Message.

    Science.gov (United States)

    Trampiets, Frances

    1995-01-01

    Highlights the importance of using music, multimedia, video, and computers to enrich and enhance religious education, and of integrating media education into faith formation. Suggests that media literacy plays an important role in increasing awareness of the influence of mass media on society. (DJM)

  20. Social Media Empowerment (deel IV)

    NARCIS (Netherlands)

    A. Cox

    2011-01-01

    full text via link. Social media stellen mensen, merken en bedrijven in staat om zichzelf te versterken. Soms wordt optimaal gebruik gemaakt van Social Media Empowerment, bijvoorbeeld bij het versterken van de brand equity zoals bij KLM en Jillz. Soms wordt er minder goed gebruik van social media