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Sample records for oh-84b oh-105 ih-102

  1. Mixed quantum/classical approach to OH-stretch inelastic incoherent neutron scattering spectroscopy for ambient and supercooled liquid water and ice Ih

    Energy Technology Data Exchange (ETDEWEB)

    Shi, L.; Skinner, J. L. [Theoretical Chemistry Institute and Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706 (United States)

    2015-07-07

    OH-stretch inelastic incoherent neutron scattering (IINS) has been measured to determine the vibrational density of states (VDOS) in the OH-stretch region for liquid water, supercooled water, and ice Ih, providing complementary information to IR and Raman spectroscopies about hydrogen bonding in these phases. In this work, we extend the combined electronic-structure/molecular-dynamics (ES/MD) method, originally developed by Skinner and co-workers to simulate OH-stretch IR and Raman spectra, to the calculation of IINS spectra with small k values. The agreement between theory and experiment in the limit k → 0 is reasonable, further validating the reliability of the ES/MD method in simulating OH-stretch spectroscopy in condensed phases. The connections and differences between IINS and IR spectra are analyzed to illustrate the advantages of IINS over IR in estimating the OH-stretch VDOS.

  2. Mixed quantum/classical approach to OH-stretch inelastic incoherent neutron scattering spectroscopy for ambient and supercooled liquid water and ice Ih

    International Nuclear Information System (INIS)

    Shi, L.; Skinner, J. L.

    2015-01-01

    OH-stretch inelastic incoherent neutron scattering (IINS) has been measured to determine the vibrational density of states (VDOS) in the OH-stretch region for liquid water, supercooled water, and ice Ih, providing complementary information to IR and Raman spectroscopies about hydrogen bonding in these phases. In this work, we extend the combined electronic-structure/molecular-dynamics (ES/MD) method, originally developed by Skinner and co-workers to simulate OH-stretch IR and Raman spectra, to the calculation of IINS spectra with small k values. The agreement between theory and experiment in the limit k → 0 is reasonable, further validating the reliability of the ES/MD method in simulating OH-stretch spectroscopy in condensed phases. The connections and differences between IINS and IR spectra are analyzed to illustrate the advantages of IINS over IR in estimating the OH-stretch VDOS

  3. OH-point defects in quartz in B- and Li-bearing systems and their application to pegmatites

    Science.gov (United States)

    Baron, M. A.; Stalder, R.; Konzett, J.; Hauzenberger, C. A.

    2015-01-01

    OH incorporation in quartz in Al-, B- and Li-bearing systems (granitic systems containing tourmaline or spodumene) was studied experimentally in order to investigate the effect of pressure, temperature and chemical impurities on the generation of OH-defects. High-pressure experiments were carried out at pressures between 5 and 25 kbar and temperatures between 800 and 900 °C, and OH-contents in quartz were calculated from IR absorption spectra measured on oriented quartz crystals. IR absorption features were assigned to impurity substitutions, such as AlOH (3,420, 3,379 and 3,315 cm-1) and BOH (3,595 cm-1), LiOH (3,483 cm-1), and hydrogarnet substitution (4H)Si defects (3,583 cm-1). Results indicate a negative correlation of incorporated Al-specific OH-defect content versus pressure (630 ± 130 wt ppm H2O at 5 kbar to 102 ± 6 wt ppm H2O at 25 kbar), but no clear correlation of B-specific OH-defects with pressure. In runs initially containing spodumene, virtually OH-free quartzes were observed at pressures ≥10 kbar, where impurity cations compensate each other forming an anhydrous eucryptite-defect component. In contrast, at 5 kbar, both Li- ad Al-specific OH-defects are observed (corresponding to 470 ± 75 wt ppm H2O). Results from this study may therefore be used to monitor formation conditions of quartz in terms of pressure and trace metal saturation of the crystallizing petrological system. IR spectra obtained from natural quartz grains from a tourmaline-bearing pegmatite exhibit B- and Al-related OH-bands. The B-related OH-band is also exhibited in quartz from a tourmaline + spodumene-bearing pegmatite. Li- and Al-related OH-bands, however, are subordinate or not observed at all in the spodumene-bearing system, which suggests that OH-vibrations do not reflect absolute Li-contents in quartz due to efficient coupled substitution involving Al. Data from experimental runs and natural specimens indicate that the B-related OH-band can be used as a rough proxy for

  4. Crystal structure and magnetism of Fe2(OH)[B2O4(OH)

    DEFF Research Database (Denmark)

    Kurayoshi, Yotaro; Hara, Shigeo; Sato, Hirohiko

    2014-01-01

    The structure and magnetism of Fe2(OH)[B2O4(OH)] are reported. Powder x-ray diffraction reveals a characteristic structure containing two crystallographically independent zigzag-ladder chains of magnetic Fe2+ ions. Magnetization measurements reveal a phase transition at 85 K, below which a weak...... spontaneous magnetization (approximate to 0.15 μB/Fe) appears. Below 85 K, magnetization increases with decreasing temperature down to 70 K, below which it decreases and approaches a constant value at low temperature. The Mossbauer spectrum at room temperature is composed of two paramagnetic doublets...... corresponding to the two crystallographic Fe2+ sites. Below 85 K, each doublet undergoes further splitting because of the magnetic hyperfine fields. The temperature dependence of the hyperfine field is qualitatively different for the two distinguishable Fe2+ sites. This is responsible for the anomalous...

  5. oh sport

    Directory of Open Access Journals (Sweden)

    Elena Grigoryeva

    2017-03-01

    Sports play a very important and diverse role in the present-day global culture. On the occasion of the 105th anniversary of Coubertin’s Ode we would like to wish sports to return to the main words of the Ode and to correspond with them: “Oh sport, you are the peace”.

  6. Solid-State Synthesis and Structure of the Enigmatic Ammonium Octaborate: (NH4)2[B7O9(OH)5]·3/4B(OH)3·5/4H2O.

    Science.gov (United States)

    Neiner, Doinita; Sevryugina, Yulia V; Schubert, David M

    2016-09-06

    The compound known since the 19th century as ammonium octaborate was structurally characterized revealing the ammonium salt of the ribbon isomer of the heptaborate anion, [B7O9(OH)5](2-), with boric acid and water molecules. Of composition (NH4)2B7.75O12.63·4.88H2O, it approximates the classical ammonium octaborate composition (NH4)2B8O13·6H2O and has the structural formula {(NH4)2[B7O9(OH)5]}4·3B(OH)3·5H2O. It spontaneously forms at room temperature in solid-state mixtures of ammonium tetraborate and ammonium pentaborate. It crystallizes in the monoclinic space group P21/c with a = 11.4137(2) Å, b = 11.8877(2) Å, c = 23.4459(3) Å, β = 90.092(1)°, V = 3181.19(8) Å(3), and Z = 2 and contains well-ordered ammonium cations and [B7O9(OH)5](2-) anions and disordered B(OH)3 and H2O molecules linked by extensive H bonding. Expeditious solid-state formation of the heptaborate anion under ambient conditions has important implications for development of practical syntheses of industrially useful borates.

  7. MERLIN observations of the OH/IR stars OH 53.6-0.2, OH 138.0+7.2 and OH 141.7+3.5

    International Nuclear Information System (INIS)

    Chapman, J.; Cohen, R.J.; Norris, R.P.; Diamond, P.J.; Booth, R.S.

    1984-01-01

    OH maser emission from the three OH/IR stars OH 53.6-0.2, OH 138.0+7.2 and OH 141.7+3.5 has been mapped with an angular resolution of 0.28 arcsec and a velocity resolution of 0.7 km s -1 using the Jodrell Bank MERLIN array. Maps are presented of the 1612-MHz OH emission over individual velocity ranges. The maps are consistent with a uniform expanding shell model, and by fitting such models to the data the angular diameters of the shells have been estimated to an accuracy of approx. 25 per cent. (author)

  8. Observations of OH and HO2 radicals in coastal Antarctica

    Directory of Open Access Journals (Sweden)

    S. J.-B. Bauguitte

    2007-08-01

    Full Text Available OH and HO2 radical concentrations have been measured in the boundary layer of coastal Antarctica for a six-week period during the austral summer of 2005. The measurements were performed at the British Antarctic Survey's Halley Research Station (75° 35' S, 26° 19' W, using the technique of on-resonance laser-induced fluorescence to detect OH, with HO2 measured following chemical conversion through addition of NO. The mean radical levels were 3.9×105 molecule cm−3 for OH, and 0.76 ppt for HO2 (ppt denotes parts per trillion, by volume. Typical maximum (local noontime levels were 7.9×105 molecule cm−3 and 1.50 ppt for OH and HO2 respectively. The main sources of HOx were photolysis of O3 and HCHO, with potentially important but uncertain contributions from HONO and higher aldehydes. Of the measured OH sinks, reaction with CO and CH4 dominated, however comparison of the observed OH concentrations with those calculated via the steady state approximation indicated that additional co-reactants were likely to have been present. Elevated levels of NOx resulting from snowpack photochemistry contributed to HOx cycling and enhanced levels of OH, however the halogen oxides IO and BrO dominated the CH3O2 – HO2 – OH conversion in this environment, with associated ozone destruction.

  9. Impact of calcium ion on cytotoxic effect of the boroxine derivative, K2[B3O3F4OH].

    Science.gov (United States)

    Ivankovic, Sinisa; Stojkovic, Ranko; Maksimovic, Milka; Galic, Borivoj; Milos, Mladen

    2016-01-01

    The effect of Ca 2+ ions on the cytotoxic ability of boron heterocyclic compound dipotassium-trioxohydroxytetrafluorotriborate (K 2 [B 3 O 3 F 4 OH]), on in vitro tumor cells (mammary adenocarcinoma 4T1, melanoma B16F10 and squamous cell carcinoma SCCVII) and non-tumoral fibroblast cells (mouse dermal L929 and hamster lung V79) was examined. At small concentrations of Ca 2+ ions (0.42 mM), K 2 [B 3 O 3 F 4 OH] (3.85 mM) has a very strong cytotoxic effect on all cancer cells tested (89.1, 85.6 and 84.6%) and significantly less effect on normal cells (19.5 and 24.2%), respectively. Applying larger concentrations of Ca 2+ ions (9.42-72.42 mM), at the same concentration of K 2 [B 3 O 3 F 4 OH], no significant cytotoxic effect was detected on cancer cells and normal cells investigated. The selective ability of K 2 [B 3 O 3 F 4 OH], in the medium with a low concentration of Ca 2+ ions has a strong cytotoxic effect on cancer cells and very weak effect in normal cells, opens up the possibility of its application in antitumor therapy.

  10. Coal demineralization with Ca(OH)2. Hydrothermal reaction between Ca(OH)2 and quartz; Ca(OH)2 wo mochiita sekitan no kagakuteki dakkai. Ca(OH)2 to sekitan no suinetsu hanno

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.; Tomita, A. [Tohoku University, Sendai (Japan). Institute for Chemical Reaction Science

    1996-10-28

    Coal demineralization mechanism and its optimum condition were studied by hydrothermal reaction between Ca(OH)2 and quartz as a coal demineralization model. In experiment, the mixture of powder quartz and Ca(OH)2 water slurry was subjected to reaction in an autoclave under spontaneous pressure at 175-340{degree}C. After dried in N2 gas atmosphere at 105{degree}C, the reaction product was analyzed by X-ray diffraction, thermo-balance and differential thermal analysis. In measurement of quartz conversion, the specimen was analyzed by X-ray diffraction after removal of bound water by heat treatment at 850{degree}C. The mixture of clean coal deashed by NaOH and a fixed amount of quartz was also used as specimen for experiment. As the experimental result, dicalcium silicate hydrate was mainly produced at 175{degree}C, and the product changed into xonotlite through tobermorite by longer treatment at higher temperature. For complete reaction of quartz, heat treatments for 7 and 5 hours at 300 and 400{degree}C were necessary, respectively. 2 refs., 2 figs., 2 tabs.

  11. Origin of the OH vibrational blue shift in the LiOH crystal.

    Science.gov (United States)

    Hermansson, Kersti; Gajewski, Grzegorz; Mitev, Pavlin D

    2008-12-25

    The O-H vibrational frequency in crystalline hydroxides is either upshifted or downshifted by its crystalline surroundings. In the LiOH crystal, the experimental gas-to-solid O-H frequency upshift ("blue shift") is approximately +115 cm(-1). Here plane-wave DFT calculations for the isotope-isolated LiOH crystal have been performed and we discuss the origin of the OH frequency upshift, and the nature of the OH group and the interlayer interactions. We find that (1) the vibrational frequency upshift originates from interactions within the LiOH layer; this OH upshift is slightly lessened by the interlayer interactions; (2) the interlayer O-H - - - H-O interaction is largely electrostatic in character (but there is no hydrogen bonding); (3) the gas-to-solid vibrational shift for OH in LiOH(s) and its subsystems qualitatively adheres to a parabola-like "frequency vs electric field strength" correlation curve, which has a maximum for a positive electric field, akin to the correlation curve earlier found in the literature for an isolated OH(-) ion in an electric field.

  12. Managing OHS

    DEFF Research Database (Denmark)

    Hull Kristensen, Peer

    2011-01-01

    Contrary to a widely held view, rather than seeing the certification of Occupational Health and Safety (OHS) as a barrier to increasing employee participation, this article views new ways of structuring participation as a necessary step towards making improvements in OHS management systems....... The article first considers how work organization has changed and then in a similar way traces how bargaining has shifted from being distributive to become integrative to create a fundamental change in the negotiation regime. Finally, by analyzing an OHS-certified firm in greater depth, the article shows how...... solutions for improvements in OHS management and notable bottom-up formulations of OHS benchmarks may help us discover how the organizational form of firms with high-performance work organization can be developed through new participatory structures....

  13. A low plasma 1,25(OH)2 vitamin D/PTH (1-84) ratio predicts worsening of renal function in patients with chronic heart failure.

    Science.gov (United States)

    Masson, Serge; Barlera, Simona; Colotta, Francesco; Magnoli, Michela; Bonelli, Fabrizio; Moro, Milena; Marchioli, Roberto; Tavazzi, Luigi; Tognoni, Gianni; Latini, Roberto

    2016-12-01

    Dysregulation of the vitamin D system promotes renal dysfunction and has direct detrimental effects on the heart. Progressive deterioration of renal function is common in patients with chronic heart failure (HF) and is invariably associated with unfavorable outcomes which can be improved by early identification and timely interventions. We examined the relation between two plasma markers of vitamin D metabolism and worsening of renal function (WRF) in a large cohort of patients with chronic HF. Plasma levels of 1,25-dihydroxyvitamin D (1,25(OH) 2 D) and parathyroid hormone PTH (1-84) were measured in 1237 patients with clinical evidence of chronic and stable HF enrolled in the multicentre GISSI-HF trial and followed for 3.9years. We examined the relation of 1,25(OH) 2 D, PTH(1-84), and their ratio with WRF, defined as first increase in serum creatinine concentration ≥0.3mg/dL and ≥25% at two consecutive measurements at any time during the study. Lower 1,25(OH) 2 D/PTH(1-84) ratio was associated with a higher baseline serum concentration of creatinine, winter season, female sex and older age; 335 patients (29.6%) experienced an episode of WRF. After adjustment, a lower 1,25(OH) 2 D/PTH(1-84) ratio remained significantly associated with a higher risk of WRF (HR=0.75 [0.62-0.90], p=0.002) and correctly reclassified events. This ratio also independently predicted mortality and admission to hospital for cardiovascular reasons. The plasma 1,25(OH) 2 D/PTH(1-84) ratio is a promising indicator of future risk of deterioration of renal function in patients with chronic HF and mild renal impairment, that may serve to optimize therapies and improve outcomes. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  14. Photoionization of the OH radical

    International Nuclear Information System (INIS)

    Dehmer, P.M.

    1985-01-01

    The hydroxyl radical (OH) is one of the most thoroughly studied free radicals because of its importance in atmospheric chemistry, combustion processes, and the interstellar medium. Detailed experimental and theoretical studies have been performed on the ground electronic state (X 2 PI/sub i/) and on the four lowest bound excited electronic states (A 2 Σ + , B 2 Σ + , D 2 Σ - , and C 2 Σ + ). However, because it is difficult to distinguish the spectrum of OH from the spectra of the various radical precursors, the absorption spectrum in the wavelength region below 1200 A has not been well characterized. In the present work, the spectrum of OH has been determined in the wavelength region from 750 to 950 A using the technique of photoionization mass spectrometry. This technique allows complete separation of the spectrum of OH from that of the other components of the discharge and permits the unambiguous determination of the spectrum of OH

  15. Constraints on the OH-to-H Abundance Ratio in Infrared-bright Galaxies Derived from the Strength of the OH 35 μm Absorption Feature

    Science.gov (United States)

    Stone, Myra; Veilleux, Sylvain; González-Alfonso, Eduardo; Spoon, Henrik; Sturm, Eckhard

    2018-02-01

    We analyze Spitzer/InfraRed Spectrograph (IRS) observations of the OH 35 μm feature in 15 nearby (z ≲ 0.06) (ultra-)luminous infrared galaxies (U/LIRGs). All objects exhibit OH 35 μm purely in absorption, as expected. The small optical depth of this transition makes the strength of this feature a good indicator of the true OH column density. The measured OH 35 μm equivalent widths imply an average OH column density and a 1-σ standard deviation to the mean of {N}{OH}=1.31+/- 0.22× {10}17 cm‑2. This number is then compared with the hydrogen column density for a typical optical depth at 35 μm of ∼0.5 and gas-to-dust ratio of 125 to derive an OH-to-H abundance ratio of {X}{OH}=1.01+/- 0.15× {10}-6. This abundance ratio is formally a lower limit. It is consistent with the values generally assumed in the literature. The OH 35 μm line profiles predicted from published radiative transfer models constrained by observations of OH 65, 79, 84, and 119 μm in 5 objects (Mrk 231, Mrk 273, IRAS F05189-2524, IRAS F08572+3915, and IRAS F20551-4250) are also found to be consistent with the IRS OH 35 μm spectra.

  16. Vibrational spectroscopic study of poldervaartite CaCa[SiO3(OH)(OH)

    Science.gov (United States)

    Frost, Ray L.; López, Andrés; Scholz, Ricardo; Lima, Rosa Malena Fernandes

    2015-02-01

    We have studied the mineral poldervaartite CaCa[SiO3(OH)(OH)] which forms a series with its manganese analogue olmiite CaMn[SiO3(OH)](OH) using a range of techniques including scanning electron microscopy, thermogravimetric analysis, Raman and infrared spectroscopy. Chemical analysis shows the mineral is reasonably pure and contains only calcium and manganese with low amounts of Al and F. Thermogravimetric analysis proves the mineral decomposes at 485 °C with a mass loss of 7.6% compared with the theoretical mass loss of 7.7%. A strong Raman band at 852 cm-1 is assigned to the SiO stretching vibration of the SiO3(OH) units. Two Raman bands at 914 and 953 cm-1 are attributed to the antisymmetric vibrations. Intense prominent peaks observed at 3487, 3502, 3509, 3521 and 3547 cm-1 are assigned to the OH stretching vibration of the SiO3(OH) units. The observation of multiple OH bands supports the concept of the non-equivalence of the OH units. Vibrational spectroscopy enables a detailed assessment of the molecular structure of poldervaartite.

  17. Spatial distribution of FIR rotationally excited CH+ and OH emission lines in the Orion Bar PDR⋆

    Science.gov (United States)

    Parikka, A.; Habart, E.; Bernard-Salas, J.; Goicoechea, J. R.; Abergel, A.; Pilleri, P.; Dartois, E.; Joblin, C.; Gerin, M.; Godard, B.

    2016-01-01

    Context The methylidyne cation (CH+) and hydroxyl (OH) are key molecules in the warm interstellar chemistry, but their formation and excitation mechanisms are not well understood. Their abundance and excitation are predicted to be enhanced by the presence of vibrationally excited H2 or hot gas (~500–1000 K) in photodissociation regions with high incident FUV radiation field. The excitation may also originate in dense gas (> 105 cm−3) followed by nonreactive collisions with H2, H, and electrons. Previous observations of the Orion Bar suggest that the rotationally excited CH+ and OH correlate with the excited CO, a tracer of dense and warm gas, and formation pumping contributes to CH+ excitation. Aims Our goal is to examine the spatial distribution of the rotationally excited CH+ and OH emission lines in the Orion Bar in order to establish their physical origin and main formation and excitation mechanisms. Methods We present spatially sampled maps of the CH+ J=3-2 transition at 119.8 µm and the OH Λ-doublet at 84 µm in the Orion Bar over an area of 110″×110″ with Herschel (PACS). We compare the spatial distribution of these molecules with those of their chemical precursors, C+, O and H2, and tracers of warm and dense gas (high-J CO). We assess the spatial variation of CH+ J=2-1 velocity-resolved line profile at 1669 GHz with Herschel HIFI spectrometer observations. Results The OH and especially CH+ lines correlate well with the high-J CO emission and delineate the warm and dense molecular region at the edge of the Bar. While notably similar, the differences in the CH+ and OH morphologies indicate that CH+ formation and excitation are strongly related to the observed vibrationally excited H2. This, together with the observed broad CH+ line widths, indicates that formation pumping contributes to the excitation of this reactive molecular ion. Interestingly, the peak of the rotationally excited OH 84 µm emission coincides with a bright young object, proplyd

  18. OH vibrational activation and decay dynamics of CH4-OH entrance channel complexes

    International Nuclear Information System (INIS)

    Wheeler, Martyn D.; Tsiouris, Maria; Lester, Marsha I.; Lendvay, Gyoergy

    2000-01-01

    Infrared spectroscopy has been utilized to examine the structure and vibrational decay dynamics of CH 4 -OH complexes that have been stabilized in the entrance channel to the CH 4 +OH hydrogen abstraction reaction. Rotationally resolved infrared spectra of the CH 4 -OH complexes have been obtained in the OH fundamental and overtone regions using an IR-UV (infrared-ultraviolet) double-resonance technique. Pure OH stretching bands have been identified at 3563.45(5) and 6961.98(4) cm-1 (origins), along with combination bands involving the simultaneous excitation of OH stretching and intermolecular bending motions. The infrared spectra exhibit extensive homogeneous broadening arising from the rapid decay of vibrationally activated CH 4 -OH complexes due to vibrational relaxation and/or reaction. Lifetimes of 38(5) and 25(3) ps for CH 4 -OH prepared with one and two quanta of OH excitation, respectively, have been extracted from the infrared spectra. The nascent distribution of the OH products from vibrational predissociation has been evaluated by ultraviolet probe laser-induced fluorescence measurements. The dominant inelastic decay channel involves the transfer of one quantum of OH stretch to the pentad of CH 4 vibrational states with energies near 3000 cm-1. The experimental findings are compared with full collision studies of vibrationally excited OH with CH 4 . In addition, ab initio electronic structure calculations have been carried out to elucidate the minimum energy configuration of the CH 4 -OH complex. The calculations predict a C 3v geometry with the hydrogen of OH pointing toward one of four equivalent faces of the CH 4 tetrahedron, consistent with the analysis of the experimental infrared spectra. (c) 2000 American Institute of Physics

  19. Reaction OH + OH studied over the 298-834 K temperature and 1-100 bar pressure ranges.

    Science.gov (United States)

    Sangwan, Manuvesh; Chesnokov, Evgeni N; Krasnoperov, Lev N

    2012-06-21

    Self-reaction of hydroxyl radicals, OH + OH → H(2)O + O (1a) and OH + OH → H(2)O(2) (1b), was studied using pulsed laser photolysis coupled to transient UV-vis absorption spectroscopy over the 298-834 K temperature and 1-100 bar pressure ranges (bath gas He). A heatable high-pressure flow reactor was employed. Hydroxyl radicals were prepared using reaction of electronically excited oxygen atoms, O((1)D), produced in photolysis of N(2)O at 193 nm, with H(2)O. The temporal behavior of OH radicals was monitored via transient absorption of light from a dc discharge in H(2)O/Ar low-pressure resonance lamp at ca. 308 nm. The absolute intensity of the photolysis light was determined by accurate in situ actinometry based on the ozone formation in the presence of molecular oxygen. The results of this study combined with the literature data indicate that the rate constant of reaction 1a, associated with the pressure independent component, decreases with temperature within the temperature range 298-414 K and increases above 555 K. The pressure dependent rate constant for (1b) was parametrized using the Troe expression as k(1b,inf) = (2.4 ± 0.6) × 10(-11)(T/300)(-0.5) cm(3) molecule(-1) s(-1), k(1b,0) = [He] (9.0 ± 2.2) × 10(-31)(T/300)(-3.5±0.5) cm(3) molecule(-1) s(-1), F(c) = 0.37.

  20. Raman spectra from very concentrated aqueous NaOH and from wet and dry, solid, and anhydrous molten, LiOH, NaOH, and KOH.

    Science.gov (United States)

    Walrafen, George E; Douglas, Rudolph T W

    2006-03-21

    High-temperature, high-pressure Raman spectra were obtained from aqueous NaOH solutions up to 2NaOHH2O, with X(NaOH)=0.667 at 480 K. The spectra corresponding to the highest compositions, X(NaOH)> or =0.5, are dominated by H3O2-. An IR xi-function dispersion curve for aqueous NaOH, at 473 K and 1 kbar, calculated from the data of Franck and Charuel indicates that the OH- ion forms H3O2- by preferential H bonding with nonhydrogen-bonded OH groups. Raman spectra from wet to anhydrous, solid LiOH, NaOH, and KOH yield sharp, symmetric OH- stretching peaks at 3664, 3633, and 3596 cm(-1), respectively, plus water-related, i.e., H3O2-, peaks near LiOH, 3562 cm(-1), NaOH, 3596 cm(-1), and, KOH, 3500 cm(-1). Absence of H3O2- peaks from the solid assures that the corresponding melt is anhydrous. Raman spectra from the anhydrous melts yield OH- stretching peak frequencies: LiOH, 3614+/-4 cm(-1), 873 K; NaOH, 3610+/-2 cm(-1), 975 K; and, KOH, 3607+/-2 cm(-1), 773 K, but low-frequency asymmetry due to ion-pair interactions is present which is centered near 3550 cm(-1). The ion-pair-related asymmetry corresponds to the sole IR maximum near 3550 cm(-1) from anhydrous molten NaOH, at 623 K. Bose-Einstein correction of published low-frequency Raman data from molten LiOH revealed an acoustic phonon, near 205 cm(-1), related to restricted translation of OH- versus Li+, and an optical phonon, at 625 cm(-1) and tau approximately 0.05 ps, due to protonic precession and/or pendular motion. Strong H bonding between water and the O atom of OH- forms H3O2-, but the proton of OH- does not bond with H significantly. Large Raman bandwidths (aqueous solutions) are explained in terms of inhomogeneous broadening due to proton transfer in a double well. Vibrational assignments are presented for H3O2-.

  1. Interaction between OHS regulation and OHS certification in Denmark

    DEFF Research Database (Denmark)

    Hendriksen, Kåre; Jørgensen, Kirsten; Jørgensen, Ulrik

    2010-01-01

    In 2001, the Danish Parliament approved a law on OHS certification that provided economic support to enterprises/organizations that were certified according to one of the two national OHS standards. These certified enterprises/organizations were also exempt from the initial inspection by the Danish...... Working Environment Authority, which they would otherwise be required to pay for. In practice, this meant that inspection of the certified enterprises was transferred to the certification bodies unless a work accident or work-caused ailment or the like was reported. In 2005, the law was revised so...... certification has existed as a form of substitute inspection for almost 10 years, no systematic evaluation of the effects of OHS certification on the OHS, and thereby the validity of the certificate, has been made. In several cases, however, certified enterprises/organizations have received injunctions...

  2. Synthesis and structure determination of new open-framework chromium carboxylate MIL-105 or CrIII(OH).{O2C-C6(CH3)4-CO2}.nH2O

    International Nuclear Information System (INIS)

    Serre, Christian; Millange, Franck; Devic, Thomas; Audebrand, Nathalie; Van Beek, Wouter

    2006-01-01

    Two new three-dimensional chromium(III) dicarboxylate, MIL-105 or Cr III (OH).{O 2 C-C 6 (CH 3 ) 4 -CO 2 }.nH 2 O, have been obtained under hydrothermal conditions, and their structures solved using X-ray powder diffraction data. Both solids are structural analogs of the known Cr benzenedicarboxylate compound (MIL-53). Both contain trans corner-sharing CrO 4 (OH) 2 octahedral chains connected by tetramethylterephthalate di-anions. Each chain is linked by the ligands to four other chains to form a three-dimensional framework with an array of 1D pores channels. The pores of the high temperature form of the solid, MIL-105ht, are empty. However, MIL-105ht re-hydrates at room temperature to finally give MIL-105lt with pores channels filled with free water molecules (lt: low temperature form; ht: high temperature form). The thermal behaviour of the two solids has been investigated using TGA. Crystal data for MIL-105ht: monoclinic space group C2/c with a = 19.653(1) A, b = 9.984(1) A, c = 6.970(1) A, β = 110.67(1) o and Z = 4. Crystal data for MIL-105lt: orthorhombic space group Pnam with a = 17.892(1) A, b = 11.165(1) A, c = 6.916(1) A and Z = 4

  3. OH+ IN DIFFUSE MOLECULAR CLOUDS

    International Nuclear Information System (INIS)

    Porras, A. J.; Federman, S. R.; Welty, D. E.; Ritchey, A. M.

    2014-01-01

    Near ultraviolet observations of OH + and OH in diffuse molecular clouds reveal a preference for different environments. The dominant absorption feature in OH + arises from a main component seen in CH + (that with the highest CH + /CH column density ratio), while OH follows CN absorption. This distinction provides new constraints on OH chemistry in these clouds. Since CH + detections favor low-density gas with small fractions of molecular hydrogen, this must be true for OH + as well, confirming OH + and H 2 O + observations with the Herschel Space Telescope. Our observed correspondence indicates that the cosmic ray ionization rate derived from these measurements pertains to mainly atomic gas. The association of OH absorption with gas rich in CN is attributed to the need for a high enough density and molecular fraction before detectable amounts are seen. Thus, while OH + leads to OH production, chemical arguments suggest that their abundances are controlled by different sets of conditions and that they coexist with different sets of observed species. Of particular note is that non-thermal chemistry appears to play a limited role in the synthesis of OH in diffuse molecular clouds

  4. Synthesis of NaOH-Modified TiOF2 and Its Enhanced Visible Light Photocatalytic Performance on RhB

    Directory of Open Access Journals (Sweden)

    Chentao Hou

    2017-08-01

    Full Text Available NaOH-modified TiOF2 was successfully prepared using a modified low-temperature hydrothermal method. Scanning electron microscopy shows that NaOH-modified TiOF2 displayed a complex network shape with network units of about 100 nm. The structures of NaOH-modified TiOF2 have not been reported elsewhere. The network shape permits the NaOH-modified TiOF2 a SBET of 36 m2∙g−1 and a pore diameter around 49 nm. X-ray diffraction characterization shows that TiOF2 and NaOH-modified TiOF2 are crystallized with a pure changed cubic phase which accords with the SEM results. Fourier transform infrared spectroscopy characterization shows that NaOH-modified TiOF2 has more O–H groups to supply more lone electron pairs to transfer from O of O–H to Ti and O of TiOF2. UV–vis diffuse reflectance spectroscopy (DRS shows that the NaOH-modified TiOF2 sample has an adsorption plateau rising from 400 to 600 nm in comparison with TiOF2, and its band gap is 2.62 eV, lower than that of TiOF2. Due to the lower band gap, more O–H groups adsorption, network morphologies with larger surface area, and sensitization progress, the NaOH-modified TiOF2 exhibited much higher photocatalytic activity for Rhodamine B (RhB degradation. In addition, considering the sensitization progress, O–H groups on TiOF2 not only accelerated the degradation rate of RhB, but also changed its degradation path. As a result, the NaOH-modified TiOF2 exhibited much higher photocatalytic activity for RhB degradation than the TiOF2 in references under visible light. This finding provides a new idea to enhance the photocatalytic performance by NaOH modification of the surface of TiOF2.

  5. Synthesis and characterization of the lead borate Pb{sub 6}B{sub 12}O{sub 21}(OH){sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Schoenegger, Sandra; Ortner, Teresa S.; Wurst, Klaus; Heymann, Gunter; Huppertz, Hubert [Innsbruck Univ. (Austria). Inst. fuer Allgemeine, Anorganische und Theoretische Chemie

    2016-11-01

    A lead borate with the composition Pb{sub 6}B{sub 12}O{sub 21}(OH){sub 6} was synthesized through a hydrothermal synthesis, using lead metaborate in combination with sodium nitrate and potassium nitrate. The compound crystallizes in the trigonal, non-centrosymmetric space group P3{sub 2} (no. 145) with the lattice parameters a = 1176.0(4), c = 1333.0(4) pm, and V = 0.1596(2) nm{sup 3}. Interestingly, the data of Pb{sub 6}B{sub 12}O{sub 21}(OH){sub 6} correct the structure of a literature known lead borate with the composition ''Pb{sub 6}B{sub 11}O{sub 18}(OH){sub 9}''. For the latter compound, nearly identical lattice parameters of a = 1176.91(7) and c = 1333.62(12) pm were reported, possessing a crystal structure, in which the localization and refinement of one boron atom was obviously overlooked. The structure of Pb{sub 6}B{sub 12}O{sub 21}(OH){sub 6} is built up from trigonal planar BO{sub 3} and tetrahedral BO{sub 4} groups forming complex chains. The Pb{sup 2+} cations are located between neighboring polyborate chains. The here reported compound Pb{sub 6}B{sub 12}O{sub 21}(OH){sub 6} and ''Pb{sub 6}B{sub 11}O{sub 18}(OH){sub 9}'' were, however, produced under different synthesis conditions. While ''Pb{sub 6}B{sub 11}O{sub 18}(OH){sub 9}'' was synthesized via a hydrothermal synthesis including ethylenediamine and acetic acid, the here reported lead borate Pb{sub 6}B{sub 12}O{sub 21}(OH){sub 6} could be obtained under moderate hydrothermal conditions (240 C) without the addition of organic reagents.

  6. Photodissociation thresholds of OH produced from CH sub 3 OH in solid neon and argon

    CERN Document Server

    Cheng, B M; Lo, W J; Lee, Y P

    2001-01-01

    Photodissociation thresholds of OH from CH sub 3 OH in solid Ne and Ar were determined via photolysis of CH sub 3 OH/Ne and CH sub 3 OH/Ar (1/200) samples in situ at 4 K. The samples were irradiated with VUV synchrotron radiation after dispersion by a Seya-Namioka monochromator. The OH photo-product was detected by means of laser-induced fluorescence technique. The increase of fluorescent intensity of OH was monitored and recorded after the matrix sample was irradiated at different wavelengths for 3-5 min. Photodissociation threshold energies of 7.13+-0.02 eV (174.0+-0.5 nm) and 7.08+-0.04 eV (175.0+-1.0 nm) were measured for OH production of CH sub 3 OH in solid Ne and Ar, respectively.

  7. Synthesis of Al(OH3 Nanostructures from Al(OH3 Microagglomerates via Dissolution-Precipitation Route

    Directory of Open Access Journals (Sweden)

    Bo Yu

    2013-01-01

    Full Text Available A facile method was developed to synthesize Al(OH3 nanostructures from Al(OH3 microagglomerates by dissolution in 9.0 mol·L−1 NaOH at 115°C followed by dilution and aging of the solution at room temperature. The influence of Al(OH3 nanoseed and surfactants as sodium dodecyl sulfate (SDS, polyethylene glycol 6000 (PEG6000, and cetyltrimethylammonium bromide (CTAB on the formation of the Al(OH3 nano-structures was investigated. The experimental results indicated that the Al(OH3 microspheres composed of nanoparticles were prepared in the blank experiment, while dispersive Al(OH3 nano-particles with a diameter of 80–100 nm were produced in the presence of Al(OH3 nano-seed and CTAB.

  8. Interpretation of rotationally excited far-infrared OH emission in Orion-KL

    International Nuclear Information System (INIS)

    Melnick, G.J.; Genzel, R.; Lugten, J.B.; California Univ., Berkeley; Max-Planck-Institut fuer Physik und Astrophysik, Garching, Germany, F.R.)

    1987-01-01

    The 2Pi(1/2) OH 163-micron J = 3/2-1/2 rotational transitions in Orion-KL were observed and an upper limit was set to the line strength of the 2II(1/2) OH 56-micron J = 9/2-7/2 doublet in this source. The 163-micron line intensities were modeled, along with the previously measured 2II(3/2) 119 and 84-micron rotational line emission and it is found that the gas in the Orion-KL postshocked region can produce OH 119-micron line emission of the same strength as measured; however, the resultant 84 and 163-micron line intensities would be weaker than observed. Shocked gas plus a second component which experiences strong radiative excitation can reproduce the observations. 35 references

  9. Total OH Reactivity Measurements in the Boreal Forest

    Science.gov (United States)

    Praplan, A. P.; Hellén, H.; Hakola, H.; Hatakka, J.

    2015-12-01

    INTRODUCTION Atmospheric total OH reactivity (Rtotal) can be measured (Kovacs and Brune, 2001; Sinha et al., 2008) or it can be calculated according to Rtotal = ∑i kOH+X_i [Xi] where kOH+X_i corresponds to the reaction rate coefficient for the reaction of OH with a given compound Xi and [Xi] its concentration. Studies suggest that in some environments a large fraction of missing reactivity, comparing calculated Rtotal with ambient total OH reactivity measurements (Di Carlo et al., 2004; Hofzumahaus et al., 2009). In this study Rtotal has been measured using the Comparative Reactivity Method (Sinha et al., 2008). Levels of the reference compound (pyrrole, C4H5N) are monitored by gas chromatography every 2 minutes and Rtotal is derived from the difference of reactivity between zero and ambient air. RESULTS Around 36 hours of preliminary total OH reactivity data (30 May until 2 June 2015) are presented in Fig. 1. Its range matches previous studies for this site (Nölscher et al., 2012; Sinha et al., 2010) and is similar to values in another pine forest (Nakashima et al., 2014). The setup used during the period presented here has been updated and more recent data will be presented, as well as a comparison with calculated OH reactivity from measured individual species. ACKNOWLEDGEMENTS This work was supported by Academy of Finland (Academy Research Fellowship No. 275608). The authors acknowledge Juuso Raine for technical support. REFERENCES Di Carlo et al. (2004). Science 304, 722-725.Hofzumahaus et al. (2009). Science 324, 1702-1704.Kovacs and Brune (2001). J. Atmos. Chem. 39, 105-122.Nakashima et al. (2014). Atmos. Env. 85, 1-8.Nölscher et al. (2012). Atmos. Chem. Phys. 12, 8257-8270.Sinha et al. (2008). Atmos. Chem. Phys. 8, 2213-2227.Sinha et al. (2010). Environ. Sci. Technol. 44, 6614-6620.

  10. Ternary Ni–Cu–OH and Ni–Co–OH electrodes for electrochemical energy storage

    KAUST Repository

    Alhebshi, Nuha; Alshareef, Husam N.

    2015-01-01

    In this project, Ni–Cu–OH and Ni–Co–OH ternary electrodes have been prepared. Different Ni:Cu and Ni:Co ratios were deposited by chemical bath deposition (CBD) at room temperature on carbon microfibers. Since Ni(OH)2 is notorious for poor cycling

  11. Facile synthesis of Co(OH)2/Al(OH)3 nanosheets with improved electrochemical properties for asymmetric supercapacitor

    Science.gov (United States)

    Zhao, Cuimei; Ren, Fang; Cao, Yang; Xue, Xiangxin; Duan, Xiaoyue; Wang, Hairui; Chang, Limin

    2018-01-01

    Sheet-like Co(OH)2/Al(OH)3 or Co(OH)2 nanomaterial has been synthesized on conducting carbon fiber paper (CFP) by a facile one-step electrochemical deposition. The binder-free Co(OH)2/Al(OH)3/CFP displays an improved electrical conductivity, electrochemical activity and material utilization than solitary Co(OH)2, therefore Co(OH)2/Al(OH)3 nanomaterial exhibits improved electrochemical properties (a maximum capacitance of 1006 Fg-1 at 2 Ag-1, with 77% retention even at a high current density of 32 Ag-1, and more than 87% of the capacitance retention after 10000 cycles at 32 Ag-1) in comparison to that of the Co(OH)2/CFP (709 Fg-1, 65%, 79%). In addition, an asymmetric supercapacitor (ASC) fabricated with Co(OH)2/Al(OH)3/CFP positive electrode and AC/CFP negative electrode demonstrates ultrahigh specific capacitance (75.8 Fg-1) and potential window (1.7 V). These encouraging results make these low-cost and eco-friendly materials promising for high-performance energy storage application.

  12. Photofragment imaging study of the CH2CCH2OH radical intermediate of the OH+allene reaction

    International Nuclear Information System (INIS)

    Raman, Arjun S.; Justine Bell, M.; Lau, K.-C.; Butler, Laurie J.

    2007-01-01

    These velocity map imaging experiments characterize the photolytic generation of one of the two radical intermediates formed when OH reacts via an addition mechanism with allene. The CH 2 CCH 2 OH radical intermediate is generated photolytically from the photodissociation of 2-chloro-2-propen-1-ol at 193 nm. Detecting the Cl atoms using [2+1] resonance-enhanced multiphoton ionization evidences an isotropic angular distribution for the Cl+CH 2 CCH 2 OH photofragments, a spin-orbit branching ratio for Cl( 2 P 1/2 ):Cl( 2 P 3/2 ) of 0.28, and a bimodal recoil kinetic energy distribution. Conservation of momentum and energy allows us to determine from this data the internal energy distribution of the nascent CH 2 CCH 2 OH radical cofragment. To assess the possible subsequent decomposition pathways of this highly vibrationally excited radical intermediate, we include electronic structure calculations at the G3//B3LYP level of theory. They predict the isomerization and dissociation transition states en route from the initial CH 2 CCH 2 OH radical intermediate to the three most important product channels for the OH+allene reaction expected from this radical intermediate: formaldehyde+C 2 H 3 , H+acrolein, and ethene+CHO. We also calculate the intermediates and transition states en route from the other radical adduct, formed by addition of the OH to the center carbon of allene, to the ketene+CH 3 product channel. We compare our results to a previous theoretical study of the O+allyl reaction conducted at the CBS-QB3 level of theory, as the two reactions include several common intermediates

  13. Photofragment imaging study of the CH2CCH2OH radical intermediate of the OH +allene reaction

    Science.gov (United States)

    Raman, Arjun S.; Justine Bell, M.; Lau, Kai-Chung; Butler, Laurie J.

    2007-10-01

    These velocity map imaging experiments characterize the photolytic generation of one of the two radical intermediates formed when OH reacts via an addition mechanism with allene. The CH2CCH2OH radical intermediate is generated photolytically from the photodissociation of 2-chloro-2-propen-1-ol at 193nm. Detecting the Cl atoms using [2+1] resonance-enhanced multiphoton ionization evidences an isotropic angular distribution for the Cl +CH2CCH2OH photofragments, a spin-orbit branching ratio for Cl(P1/22):Cl(P3/22) of 0.28, and a bimodal recoil kinetic energy distribution. Conservation of momentum and energy allows us to determine from this data the internal energy distribution of the nascent CH2CCH2OH radical cofragment. To assess the possible subsequent decomposition pathways of this highly vibrationally excited radical intermediate, we include electronic structure calculations at the G3//B3LYP level of theory. They predict the isomerization and dissociation transition states en route from the initial CH2CCH2OH radical intermediate to the three most important product channels for the OH +allene reaction expected from this radical intermediate: formaldehyde+C2H3, H +acrolein, and ethene+CHO. We also calculate the intermediates and transition states en route from the other radical adduct, formed by addition of the OH to the center carbon of allene, to the ketene+CH3 product channel. We compare our results to a previous theoretical study of the O +allyl reaction conducted at the CBS-QB3 level of theory, as the two reactions include several common intermediates.

  14. Lamellar-crossing-structured Ni(OH){sub 2}/CNTs/Ni(OH){sub 2} nanocomposite for electrochemical supercapacitor materials

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Qingnan [Department of Chemistry, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Wen, Ming, E-mail: m_wen@tongji.edu.cn [Department of Chemistry, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, Shanghai 200092 (China); Chen, Shipei [Department of Chemistry, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Wu, Qingsheng [Department of Chemistry, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, Shanghai 200092 (China)

    2015-10-15

    Ni(OH){sub 2}/CNTs/Ni(OH){sub 2} lamellar-crossing-nanostructure with a single lamellar spacing of ∼5 nm was effectively constructed through two-phase-interface reaction process followed by the CNTs crossed among the lamellar-nanostructured Ni(OH){sub 2}. The resultant nanocomposite can offer large active surface areas and short diffusion paths for electrons and ions, and is investigated as a potential pseudocapacitor electrode material for electrochemical energy storage applications. Electrochemical data demonstrate that the as-prepared nanocomposite exhibits a high specific capacitance of ∼1600 F g{sup −1} at the scan rate of 1 mV s{sup −1} in 6 M KOH solution at normal pressure and temperature, which is great higher than Ni(OH){sub 2} (∼1200 F g{sup −1}). Furthermore, Ni(OH){sub 2}/CNTs/Ni(OH){sub 2} nanocomposite shows a higher energy density (∼125 Wh kg{sup −1}, 2 A g{sup −1}) and has a slightly decrease of 5% in specific capacitance after 1000 continuous charge/discharge cycles. - Graphical abstract: As-constructed Ni(OH){sub 2}/CNTs/Ni(OH){sub 2} lamellar-crossing-nanostructure exhibits remarkable enhancement in electrochemical stability and high specific capacity of ∼1600 F g{sup −1} at a scan rate of 1 mV s{sup −1}, suggesting promising potential for supercapacitor applications. - Highlights: • New designed lamellar-crossing-structured Ni(OH){sub 2}/CNTs/Ni(OH){sub 2} nanocomposites have been firstly reported in this work. • Ni(OH){sub 2}/CNTs/Ni(OH){sub 2} lamellar-crossing-nanostructures show firm nanostructure and excellent electrochemical stability. • Ni(OH){sub 2}/CNTs/Ni(OH){sub 2} nanocomposites exhibit excellent specific capacitance. • Ni(OH){sub 2}/CNTs/Ni(OH){sub 2} nanocomposites have the potential application in electrochemical energy storage applications.

  15. Ternary Ni–Cu–OH and Ni–Co–OH electrodes for electrochemical energy storage

    KAUST Repository

    Alhebshi, Nuha

    2015-10-01

    In this project, Ni–Cu–OH and Ni–Co–OH ternary electrodes have been prepared. Different Ni:Cu and Ni:Co ratios were deposited by chemical bath deposition (CBD) at room temperature on carbon microfibers. Since Ni(OH)2 is notorious for poor cycling stability, the goal of the work was to determine if doping with Cu or Co could improve Ni(OH)2 cycling stability performance and conductivity against reaction with electrolyte. It is observed that the electrodes with Ni:Cu and Ni:Co composition ratio of 100:10 result in the optimum capacitance and cycling stability in both Ni–Cu–OH and Ni–Co–OH electrodes. This improvement in cycling stability can be attributed to the higher redox reversibility as indicated by the smaller CV redox peak separation. In addition, it is found that decreasing Cu and Co ratios, with fixed CBD time, enhances nanoflakes formation, and hence increases electrode capacitance. For the optimum composition (Ni:Co = 100:10), composites of the ternary electrodes with graphene and carbon nanofibers were also tested, with resultant improvement in potential window, equivalent series resistance, areal capacitance and cycling stability.

  16. VERY LARGE ARRAY OH ZEEMAN OBSERVATIONS OF THE STAR-FORMING REGION S88B

    Energy Technology Data Exchange (ETDEWEB)

    Sarma, A. P.; Eftimova, M. [Physics Department, DePaul University, 2219 N. Kenmore Ave., Byrne Hall 211, Chicago, IL 60614 (United States); Brogan, C. L. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Bourke, T. L. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Troland, T. H., E-mail: asarma@depaul.edu [Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506 (United States)

    2013-04-10

    We present observations of the Zeeman effect in OH thermal absorption main lines at 1665 and 1667 MHz taken with the Very Large Array toward the star-forming region S88B. The OH absorption profiles toward this source are complicated, and contain several blended components toward a number of positions. Almost all of the OH absorbing gas is located in the eastern parts of S88B, toward the compact continuum source S88B-2 and the eastern parts of the extended continuum source S88B-1. The ratio of 1665/1667 MHz OH line intensities indicates the gas is likely highly clumped, in agreement with other molecular emission line observations in the literature. S88-B appears to present a similar geometry to the well-known star-forming region M17, in that there is an edge-on eastward progression from ionized to molecular gas. The detected magnetic fields appear to mirror this eastward transition; we detected line-of-sight magnetic fields ranging from 90 to 400 {mu}G, with the lowest values of the field to the southwest of the S88B-1 continuum peak, and the highest values to its northeast. We used the detected fields to assess the importance of the magnetic field in S88B by a number of methods; we calculated the ratio of thermal to magnetic pressures, we calculated the critical field necessary to completely support the cloud against self-gravity and compared it to the observed field, and we calculated the ratio of mass to magnetic flux in terms of the critical value of this parameter. All these methods indicated that the magnetic field in S88B is dynamically significant, and should provide an important source of support against gravity. Moreover, the magnetic energy density is in approximate equipartition with the turbulent energy density, again pointing to the importance of the magnetic field in this region.

  17. VERY LARGE ARRAY OH ZEEMAN OBSERVATIONS OF THE STAR-FORMING REGION S88B

    International Nuclear Information System (INIS)

    Sarma, A. P.; Eftimova, M.; Brogan, C. L.; Bourke, T. L.; Troland, T. H.

    2013-01-01

    We present observations of the Zeeman effect in OH thermal absorption main lines at 1665 and 1667 MHz taken with the Very Large Array toward the star-forming region S88B. The OH absorption profiles toward this source are complicated, and contain several blended components toward a number of positions. Almost all of the OH absorbing gas is located in the eastern parts of S88B, toward the compact continuum source S88B-2 and the eastern parts of the extended continuum source S88B-1. The ratio of 1665/1667 MHz OH line intensities indicates the gas is likely highly clumped, in agreement with other molecular emission line observations in the literature. S88-B appears to present a similar geometry to the well-known star-forming region M17, in that there is an edge-on eastward progression from ionized to molecular gas. The detected magnetic fields appear to mirror this eastward transition; we detected line-of-sight magnetic fields ranging from 90 to 400 μG, with the lowest values of the field to the southwest of the S88B-1 continuum peak, and the highest values to its northeast. We used the detected fields to assess the importance of the magnetic field in S88B by a number of methods; we calculated the ratio of thermal to magnetic pressures, we calculated the critical field necessary to completely support the cloud against self-gravity and compared it to the observed field, and we calculated the ratio of mass to magnetic flux in terms of the critical value of this parameter. All these methods indicated that the magnetic field in S88B is dynamically significant, and should provide an important source of support against gravity. Moreover, the magnetic energy density is in approximate equipartition with the turbulent energy density, again pointing to the importance of the magnetic field in this region.

  18. In vitro and in vivo antitumor activity of the halogenated boroxine dipotassium-trioxohydroxytetrafluorotriborate (K2[B3O3F4OH]).

    Science.gov (United States)

    Ivankovic, Sinisa; Stojkovic, Ranko; Galic, Zoran; Galic, Borivoj; Ostojic, Jelena; Marasovic, Maja; Milos, Mladen

    2015-06-01

    Dipotassium-trioxohydroxytetrafluorotriborate K2[B3O3F4OH] was listed as a promising new therapeutic for cancer diseases. For in vitro and in vivo investigation of its antitumor effects 4T1 mammary adenocarcinoma, B16F10 melanoma and squamous cell carcinoma SCCVII were used. The detailed in vitro investigation undoubtedly showed that K2[B3O3F4OH] affects the growth of cancer cells. The proliferation of cells depends on the concentration so that aqueous solution of K2[B3O3F4OH], the concentrations of 10(-4) M and less, does not affect cell growth, but the concentrations of 10(-3) M or more, significantly slows cells growth. B16F10 and SCCVII cells show higher sensitivity to the cytotoxic effects of K2[B3O3F4OH] compared to 4T1 cells. Under in vivo conditions, K2[B3O3F4OH] slows the growth of all three tumors tested compared to the control, and the inhibitory effect was most pronounced during the application of the substance. There is almost no difference if K2[B3O3F4OH] was applied intraperitoneally, intratumor, peroral or as ointment. Addition of 5-FU did not further increase the antitumor efficacy of K2[B3O3F4OH].

  19. Layered Ni(OH)2-Co(OH)2 films prepared by electrodeposition as charge storage electrodes for hybrid supercapacitors.

    Science.gov (United States)

    Nguyen, Tuyen; Boudard, Michel; Carmezim, M João; Montemor, M Fátima

    2017-01-04

    Consecutive layers of Ni(OH) 2 and Co(OH) 2 were electrodeposited on stainless steel current collectors for preparing charge storage electrodes of high specific capacity with potential application in hybrid supercapacitors. Different electrodes were prepared consisting on films of Ni(OH) 2 , Co(OH) 2 , Ni 1/2 Co 1/2 (OH) 2 and layered films of Ni(OH) 2 on Co(OH) 2 and Co(OH) 2 on Ni(OH) 2 to highlight the advantages of the new architecture. The microscopy studies revealed the formation of nanosheets in the Co(OH) 2 films and of particles agglomerates in the Ni(OH) 2 films. Important morphological changes were observed in the double hydroxides films and layered films. Film growth by electrodeposition was governed by instantaneous nucleation mechanism. The new architecture composed of Ni(OH) 2 on Co(OH) 2 displayed a redox response characterized by the presence of two peaks in the cyclic voltammograms, arising from redox reactions of the metallic species present in the layered film. These electrodes revealed a specific capacity of 762 C g -1 at the specific current of 1 A g -1 . The hybrid cell using Ni(OH) 2 on Co(OH) 2 as positive electrode and carbon nanofoam paper as negative electrode display specific energies of 101.3 W h g -1 and 37.8 W h g -1 at specific powers of 0.2 W g -1 and 2.45 W g -1 , respectively.

  20. 13C, 18O, and D Fractionation Effects in the Reactions of CH3OH Isotopologues with Cl andOH Radicals

    DEFF Research Database (Denmark)

    Feilberg, Karen; Gruber-Stadler, Margaret; Johnson, Matthew Stanley

    2008-01-01

    A relative rate experiment is carried out for six isotopologues of methanol and their reactions with OH and Cl radicals. The reaction rates of CH2DOH, CHD2OH, CD3OH, 13CH3OH, and CH3 18OH with Cl and OH radicals are measured by long-path FTIR spectroscopy relative to CH3OH at 298 ( 2 K and 1013...... with measured high-resolution infrared spectra as references. The relative reaction rates defined as R ) klight/kheavy are determined to be: kOH + CH3OH/kOH + 13CH3OH ) 1.031 ( 0.020, kOH + CH3OH/kOH + CH3 18OH ) 1.017 ( 0.012, kOH + CH3OH/kOH + CH2DOH ) 1.119 ( 0.045, kOH + CH3OH/kOH + CHD2OH ) 1.326 ( 0...... reactions with CH3OH were further investigated using canonical variational transition state theory with small curvature tunneling and compared to experimental measurements as well as to those observed in CH4 and several other substituted methane species. Udgivelsesdato: 16 August 2008...

  1. Facile fabrication of carbon microspheres decorated with B(OH) 3 and α-Fe 2 O 3 nanoparticles: superior microwave absorption

    KAUST Repository

    Zhong, Bo

    2017-06-02

    We demonstrate that novel three-dimensional (3D) B(OH)3 and α-Fe2O3 nanoparticles decorated carbon microspheres (B(OH)3/α-Fe2O3-CMSs) can be fabricated via a facile thermal treatment process. The carbon microspheres with diameter of 1 to 3 μm and decorated B(OH)3 and α-Fe2O3 nanoparticles with diameters of several to tens of nanometers are successfully fabricated. These novel 3D B(OH)3/α-Fe2O3-CMS composites exhibit enhanced microwave absorption with tunable strong absorption wavebands in the frequency range of 2–18 GHz. They have a minimum reflection loss (RL) value of -52.69 dB at a thickness of 3.0 mm, and the effective absorption bandwidth for RL less than -10 dB is as large as 5.64 GHz. The enhanced microwave absorption performance arises from the synergy of the impedance matching caused by the B(OH)3 nanoparticles, dielectric loss as well as the enhancement of multiple reflection among 3D α-Fe2O3 nanocrystals. These results provide a new strategy to tune electromagnetic properties and enhance the capacity of high-efficient microwave absorbers.

  2. Facile fabrication of carbon microspheres decorated with B(OH) 3 and α-Fe 2 O 3 nanoparticles: superior microwave absorption

    KAUST Repository

    Zhong, Bo; Wang, Chaojun; Yu, Yuanlie; Xia, Long; Wen, Guangwu

    2017-01-01

    We demonstrate that novel three-dimensional (3D) B(OH)3 and α-Fe2O3 nanoparticles decorated carbon microspheres (B(OH)3/α-Fe2O3-CMSs) can be fabricated via a facile thermal treatment process. The carbon microspheres with diameter of 1 to 3 μm and decorated B(OH)3 and α-Fe2O3 nanoparticles with diameters of several to tens of nanometers are successfully fabricated. These novel 3D B(OH)3/α-Fe2O3-CMS composites exhibit enhanced microwave absorption with tunable strong absorption wavebands in the frequency range of 2–18 GHz. They have a minimum reflection loss (RL) value of -52.69 dB at a thickness of 3.0 mm, and the effective absorption bandwidth for RL less than -10 dB is as large as 5.64 GHz. The enhanced microwave absorption performance arises from the synergy of the impedance matching caused by the B(OH)3 nanoparticles, dielectric loss as well as the enhancement of multiple reflection among 3D α-Fe2O3 nanocrystals. These results provide a new strategy to tune electromagnetic properties and enhance the capacity of high-efficient microwave absorbers.

  3. Obesity hypoventilation syndrome (OHS)

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/000085.htm Obesity hypoventilation syndrome (OHS) To use the sharing features on this page, please enable JavaScript. Obesity hypoventilation syndrome (OHS) is a condition in some ...

  4. OH, HO2 and RO2 Radical and OH Reactivity Observations during the Summertime in Beijing: High In-Situ Ozone Production and Evidence of a Missing OH Source.

    Science.gov (United States)

    Whalley, L.; Ye, C.; Slater, E.; Woodward-Massey, R.; Lee, J. D.; Squires, F. A.; Hopkins, J. R.; Dunmore, R.; Shaw, M.; Hamilton, J.; Lewis, A. C.; Crilley, L.; Kramer, L. J.; Bloss, W.; Heard, D. E.

    2017-12-01

    Despite substantial reductions in primary emissions of pollutants in China over the past decade, concentrations of the secondary pollutant, ozone, still frequently exceed air quality threshold limits in urban areas during the summertime. We will present measurements of OH, HO2 and RO2 radicals and OH reactivity made in central Beijing at the Institute of Atmospheric Physics of the Chinese Academy of Sciences, close to the North 4th ring road in May and June 2017 which formed the summer phase of `An Integrated Study of AIR Pollution PROcesses'. Elevated levels of O3 (>100 ppbv) were regularly observed. NO concentrations were elevated during the morning but often decreased to below the instrument limit of detection during the afternoon hours when the ozone concentrations peaked. Biogenic emissions influenced the chemistry at the site, with several ppbv of isoprene measured during the afternoons. The OH measurements were made using the FAGE technique, equipped with an inlet pre injector (IPI) which provides an alternative method to determine the instrument background signal by injecting a scavenger to remove ambient OH and ensures an artefact-free OH measurement. Elevated levels of OH were observed, with a mean peak OH concentration of 1.2×107 molecule cm-3 at noon; but with OH concentrations reaching up to 2.5×107 molecule cm-3 on some days. Mean peak HO2 concentrations of 3×108 molecule cm-3 and total RO2 of 1.2×109 molecule cm-3 were recorded, with maximum concentrations of 1.0×109 molecule cm-3 and 4×109 molecule cm-3 observed for HO2 and RO2 respectively, suggesting significant in situ ozone production. A comparison of the artefact-free OH observations with steady state calculations, constrained to the total OH reactivity measurement and known OH precursors that were measured alongside OH, highlights a significant missing daytime OH source under low [NO], with the steady state OH concentrations approximately a factor of two lower than the OH concentrations

  5. Thermal decomposition of ammonium perchlorate in the presence of Al(OH){sub 3}·Cr(OH){sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, WenJing [Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Ping, E-mail: lipinggnipil@home.ipe.ac.cn [Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Xu, HongBin; Sun, Randi; Qing, Penghui; Zhang, Yi [Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China)

    2014-03-01

    Highlights: • The amorphous Al(OH){sub 3}·Cr(OH){sub 3} nanoparticles containing surface hydroxyls were prepared by a hydrolytic co-precipitation method. • The Al(OH){sub 3}·Cr(OH){sub 3} nanoparticles show excellent catalytic ability for AP decomposition. • The surface hydroxyls and amorphous form of Al(OH){sub 3}·Cr(OH){sub 3} nanoparticles promote ammonia oxidation of AP. - Abstract: An Al(OH){sub 3}·Cr(OH){sub 3} nanoparticle preparation procedure and its catalytic effect and mechanism on thermal decomposition of ammonium perchlorate (AP) were investigated using transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis and differential scanning calorimetry (TG-DSC), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis and mass spectroscopy (TG-MS). In the preparation procedure, TEM, SAED, and FT-IR showed that the Al(OH){sub 3}·Cr(OH){sub 3} particles were amorphous particles with dimensions in the nanometer size regime containing a large amount of surface hydroxyl under the controllable preparation conditions. When the Al(OH){sub 3}·Cr(OH){sub 3} nanoparticles were used as additives for the thermal decomposition of AP, the TG-DSC results showed that the addition of Al(OH){sub 3}·Cr(OH){sub 3} nanoparticles to AP remarkably decreased the onset temperature of AP decomposition from approximately 450 °C to 245 °C. The FT-IR, RS and XPS results confirmed that the surface hydroxyl content of the Al(OH){sub 3}·Cr(OH){sub 3} nanoparticles decreased from 67.94% to 63.65%, and Al(OH){sub 3}·Cr(OH){sub 3} nanoparticles were limitedly transformed from amorphous to crystalline after used as additives for the thermal decomposition of AP. Such behavior of Al(OH){sub 3}·Cr(OH){sub 3} nanoparticles promoted the oxidation of NH{sub 3} of AP to decompose to N{sub 2}O first, as indicated by the TG-MS results, accelerating the AP thermal decomposition.

  6. Application of the Akinfiev-Diamond equation of state to neutral hydroxides of metalloids (B(OH)3, Si(OH)4, As(OH)3) at infinite dilution in water over a wide range of the state parameters, including steam conditions

    Science.gov (United States)

    Akinfiev, Nikolay N.; Plyasunov, Andrey V.

    2014-02-01

    The Akinfiev and Diamond (2003) equation of state (EoS) for aqueous nonelectrolytes was employed to describe hydroxides of metalloids (B(OH)3, Si(OH)4, As(OH)3) over a wide temperature and pressure ranges, including steam conditions. The EoS is based on the accurate knowledge of solvent (H2O) properties and requires only three empirical parameters to be fitted to experimental data, and these are independent of temperature and pressure. For nonvolatile components thermodynamic properties of species in the ideal gas state were evaluated using quantum chemical computations. The proposed approach has been tested to predict the whole set of thermodynamic properties of solutes (the chemical potential, entropy, molar volume, and molar heat capacity) over a wide range of temperatures (273-1200 K) and pressures (0.1-1000 MPa), including the near-critical region and both low and high density regions of the solvent. Thus it can be used for modeling various geochemical processes over a whole range of solvent densities, including processes in boiling fluids and a vapor phase as well. solubility data in a low density aqueous fluid (ρ1∗ 1 mol kg-1) where polymerization effects may take place (Newton and Manning, 2003); the rest of data, containing the majority of quartz solubility points at 293-1273 K, 0.1-1000 MPa. Only the 3rd part of experimental quartz solubility data has been used in the fitting procedure. Thermodynamic properties of Si(OH)4 in the ideal gas state were recently determined by the analysis of the relevant experimental data in Plyasunov (2011b). The temperature dependence of heat capacity of the molecule was adopted from comprehensive study of Rutz and Bockhorn (2005)where DFT calculations at different levels of theory including CBS-QBS and G3MP2 methods, as well as corrections for hindered rotations and scaling for vibration frequencies were employed. The adopted Cpo (T = 300-1500 K) values for gaseous Si(OH)4 were approximated by a function and used in the

  7. Comparison of OH concentration measurements by DOAS and LIF during SAPHIR chamber experiments at high OH reactivity and low NO concentration

    Directory of Open Access Journals (Sweden)

    H. Fuchs

    2012-07-01

    Full Text Available During recent field campaigns, hydroxyl radical (OH concentrations that were measured by laser-induced fluorescence (LIF were up to a factor of ten larger than predicted by current chemical models for conditions of high OH reactivity and low NO concentration. These discrepancies, which were observed in forests and urban-influenced rural environments, are so far not entirely understood. In summer 2011, a series of experiments was carried out in the atmosphere simulation chamber SAPHIR in Jülich, Germany, in order to investigate the photochemical degradation of isoprene, methyl-vinyl ketone (MVK, methacrolein (MACR and aromatic compounds by OH. Conditions were similar to those experienced during the PRIDE-PRD2006 campaign in the Pearl River Delta (PRD, China, in 2006, where a large difference between OH measurements and model predictions was found. During experiments in SAPHIR, OH was simultaneously detected by two independent instruments: LIF and differential optical absorption spectroscopy (DOAS. Because DOAS is an inherently calibration-free technique, DOAS measurements are regarded as a reference standard. The comparison of the two techniques was used to investigate potential artifacts in the LIF measurements for PRD-like conditions of OH reactivities of 10 to 30 s−1 and NO mixing ratios of 0.1 to 0.3 ppbv. The analysis of twenty experiment days shows good agreement. The linear regression of the combined data set (averaged to the DOAS time resolution, 2495 data points yields a slope of 1.02 ± 0.01 with an intercept of (0.10 ± 0.03 × 106 cm−3 and a linear correlation coefficient of R2 = 0.86. This indicates that the sensitivity of the LIF instrument is well-defined by its calibration procedure. No hints for artifacts are observed for isoprene, MACR, and different aromatic compounds. LIF measurements were approximately 30–40% (median larger than those by DOAS after MVK (20 ppbv and

  8. A roadmap for OH reactivity research

    Science.gov (United States)

    Williams, Jonathan; Brune, William

    2015-04-01

    A fundamental property of the atmosphere is the frequency of gas-phase reactions with the OH radical, the atmosphere's primary oxidizing agent. This reaction frequency is called the OH reactivity and is the inverse the lifetime of the OH radical itself, which varies from a few seconds in the clean upper troposphere to below 10 ms in forests and polluted city environments. Ever since the discovery of the OH radical's importance to tropospheric chemistry, the characterization of its overall loss rate (OH reactivity) has remained a key question. At first, this property was assessed by summing the reactivity contributions of individually measured compounds; however, as improving analytical technology revealed ever more reactive species in ambient air, it became clear that this approach could provide only a lower limit. Approximately 15 years ago, the direct measurement of total OH reactivity was conceived independently by two groups. The first publications demonstrated direct OH reactivity measurements in the laboratory (Calpini et al., 1999) based on LIDAR and in the ambient air (Kovacs and Brune, 2001) based on in situ laser induced fluorescence detection of OH.

  9. Oh No, Henrietta Got Out!

    Science.gov (United States)

    Lottero-Perdue, Pamela; Grabia, Kathryn; Sandifer, Cody

    2017-01-01

    In a kindergarten classroom, exclamations like "Oh no!" may be causes for concern. However, when the students in Mrs. Grabia's classroom shouted "Oh no!" and "Uh oh!" during an engineering-infused 5E lesson, it meant that a persistent little robot had pushed its way out of the fences they had created. It also meant…

  10. Replacement of Oxygen by Sulfur in Small Organic Molecules. 3. Theoretical Studies on the Tautomeric Equilibria of the 2OH and 4OH-Substituted Oxazole and Thiazole and the 3OH and 4OH-Substituted Isoxazole and Isothiazole in the Isolated State and in Solution

    Directory of Open Access Journals (Sweden)

    Peter I. Nagy

    2016-07-01

    Full Text Available This follow-up paper completes the author’s investigations to explore the in-solution structural preferences and relative free energies of all OH-substituted oxazole, thiazole, isoxazole, and isothiazole systems. The polarizable continuum dielectric solvent method calculations in the integral-equation formalism (IEF-PCM were performed at the DFT/B97D/aug-cc-pv(q+(dz level for the stable neutral tautomers with geometries optimized in dichloromethane and aqueous solution. With the exception of the predictions for the predominant tautomers of the 3OH isoxazole and isothiazole, the results of the IEF-PCM calculations for identifying the most stable tautomer of the given species in the two selected solvents agreed with those from experimental investigations. The calculations predict that the hydroxy proton, with the exception for the 4OH isoxazole and 4OH isothiazole, moves preferentially to the ring nitrogen or to a ring carbon atom in parallel with the development of a C=O group. The remaining, low-fraction OH tautomers will not be observable in the equilibrium compositions. Relative solvation free energies obtained by the free energy perturbation method implemented in Monte Carlo simulations are in moderate accord with the IEF-PCM results, but consideration of the ΔGsolv/MC values in calculating ΔGstot maintains the tautomeric preferences. It was revealed from the Monte Carlo solution structure analyses that the S atom is not a hydrogen-bond acceptor in any OH-substituted thiazole or isothiazole, and the OH-substituted isoxazole and oxazole ring oxygens may act as a weak hydrogen-bond acceptor at most. The molecules form 1.0−3.4 solute−water hydrogen bonds in generally unexplored numbers at some specific solute sites. Nonetheless, hydrogen-bond formation is favorable with the NH, C=O and OH groups.

  11. Biodistribution and tumor uptake of C60(OH)x in mice

    International Nuclear Information System (INIS)

    Ji Zhiqiang; Sun Hongfang; Wang Haifang; Xie Qunying; Liu Yuangfang; Wang Zheng

    2006-01-01

    Radiolabeling of fullerol, 125 I-C 60 (OH) x , was performed by the traditional chloramine-T method. The C-I covalent bond in I-C 60 (OH) x was characterized by X-ray photoelectron spectroscopy (XPS) that was sufficiently stable for in vivo study. Laser light scattering spectroscopy clearly showed that C 60 (OH) x aggregated to large nanoparticle clumps with a wide range of distribution. The clumps formed were also visualized by transmission electron microscope (TEM). We examined the biodistribution and tumor uptake of C 60 (OH) x in five mouse bearing tumor models, including mouse H22 hepatocarcinoma, human lung giantcellcarcinoma PD, human colon cancer HCT-8, human gastric cancer MGC803, and human OS732 osteosarcoma. The accumulation ratios of 125 I-C 60 (OH) x in mouse H22 hepatocarcinoma to that in normal muscle tissue (T/N) and blood (T/B) at 1, 6, 24 and 72 h, reveal that 125 I-C 60 (OH) x gradually accumulates in H22 tumor, and retains for a quite long period (e.g., T/N 3.41, T/B 3.94 at 24 h). For the other four tumor models, the T/N ratio at 24 h ranges within 1.21-6.26, while the T/B ratio ranges between 1.23 and 4.73. The accumulation of C 60 (OH) x in tumor is mostly due to the enhanced permeability and retention effect (EPR) and the phagocytosis of mononuclear phagocytes. Hence, C 60 (OH) x might serve as a photosensitizer in the photodynamic therapy of some kinds of tumor

  12. Cation incorporation into zirconium oxide in LiOH, NaOH, and KOH solutions

    International Nuclear Information System (INIS)

    Jeong, Y.H.; Kim, K.H.; Baek, J.H.

    1999-01-01

    To investigate the cation incorporation into zirconium oxide, SIMS analysis was performed on the specimens prepared to have an equal oxide thickness in LiOH, NaOH, and KOH solutions. Even though they have an equal oxide thickness in LiOH, NaOH, and KOH solutions, the penetration depth of cation into the oxide decreased with an increase in the ionic radius of cation. The cation is considered to control the corrosion in alkali hydroxide solutions and its effect is dependent on the concentration of alkali and the oxide thickness. The slight enhancement of the corrosion rate at a low concentration is thought to be caused by cation incorporation into oxide, while the significant acceleration at a high concentration is due to the transformation of oxide microstructures that would be also induced by cation incorporation into oxide. (orig.)

  13. Discovery of pulsed OH maser emission stimulated by a pulsar.

    Science.gov (United States)

    Weisberg, Joel M; Johnston, Simon; Koribalski, Bärbel; Stanimirovic, Snezana

    2005-07-01

    Stimulated emission of radiation has not been directly observed in astrophysical situations up to this time. Here we demonstrate that photons from pulsar B1641-45 stimulate pulses of excess 1720-megahertz line emission in an interstellar hydroxyl (OH) cloud. As this stimulated emission is driven by the pulsar, it varies on a few-millisecond time scale, which is orders of magnitude shorter than the quickest OH maser variations previously detected. Our 1612-megahertz spectra are inverted copies of the 1720-megahertz spectra. This "conjugate line" phenomenon enables us to constrain the properties of the interstellar OH line-producing gas. We also show that pulsar signals undergo significantly deeper OH absorption than do other background sources, which confirms earlier tentative findings that OH clouds are clumpier on small scales than are neutral hydrogen clouds.

  14. Global modelling of the total OH reactivity: investigations on the “missing” OH sink and its atmospheric implications

    Directory of Open Access Journals (Sweden)

    V. Ferracci

    2018-05-01

    Full Text Available The hydroxyl radical (OH plays a crucial role in the chemistry of the atmosphere as it initiates the removal of most trace gases. A number of field campaigns have observed the presence of a missing OH sink in a variety of regions across the planet. A comparison of direct measurements of the OH loss frequency, also known as total OH reactivity (kOH, with the sum of individual known OH sinks (obtained via the simultaneous detection of species such as volatile organic compounds and nitrogen oxides indicates that, in some cases, up to 80 % of kOH is unaccounted for. In this work, the UM-UKCA chemistry-climate model was used to investigate the wider implications of the missing reactivity on the oxidising capacity of the atmosphere. Simulations of the present-day atmosphere were performed and the model was evaluated against an array of field measurements to verify that the known OH sinks were reproduced well, with a resulting good agreement found for most species. Following this, an additional sink was introduced to simulate the missing OH reactivity as an emission of a hypothetical molecule, X, which undergoes rapid reaction with OH. The magnitude and spatial distribution of this sink were underpinned by observations of the missing reactivity. Model runs showed that the missing reactivity accounted for on average 6 % of the total OH loss flux at the surface and up to 50 % in regions where emissions of the additional sink were high. The lifetime of the hydroxyl radical was reduced by 3 % in the boundary layer, whilst tropospheric methane lifetime increased by 2 % when the additional OH sink was included. As no OH recycling was introduced following the initial oxidation of X, these results can be interpreted as an upper limit of the effects of the missing reactivity on the oxidising capacity of the troposphere. The UM-UKCA simulations also allowed us to establish the atmospheric implications of the newly characterised reactions of peroxy

  15. 25-Hydroxyvitamin D (25(OH)D) and biomarkers of ovarian reserve.

    Science.gov (United States)

    Jukic, Anne Marie Z; Baird, Donna D; Wilcox, Allen J; Weinberg, Clarice R; Steiner, Anne Z

    2018-07-01

    The aim of the study was to examine the associations between 25-hydroxyvitamin D (25(OH)D) and biomarkers of ovarian reserve in a large community-based sample of women. In 2010 to 2016, women aged 30 to 44 years without any known fertility problems were recruited from the Chapel Hill, NC area for a prospective time-to-pregnancy cohort study. At enrollment 561 women provided a blood sample that was used to measure 25(OH)D, anti-Müllerian hormone (AMH), follicle-stimulating hormone, and inhibin-B. Unadjusted associations were estimated with Spearman correlation coefficients. Multivariable linear regression was used to estimate associations of 25(OH)D with ovarian reserve biomarkers, after adjusting for age, race, body mass index, smoking history, and recent use of hormonal birth control. The mean 25(OH)D was 36 ng/mL (SD = 11 ng/mL). 25(OH)D was not correlated with AMH, follicle-stimulating hormone, or inhibin-B (all r < 0.03). Multivariable results with continuous hormonal outcomes were also null. For dichotomous outcomes, there was a tendency for insufficient 25(OH)D (<30 ng/mL) to be associated with low AMH (<0.7 ng/mL) (odds ratio [95% CI]: 1.8 [0.9-4]). For the most part, 25(OH)D was not associated with ovarian reserve biomarkers in a group of women trying to become pregnant. We found some evidence that low 25(OH)D (<30 ng/mL) was associated with low AMH, but this should be confirmed in studies with a higher prevalence of low 25(OH)D.

  16. A SEARCH FOR HYDROXYLAMINE (NH2OH) TOWARD SELECT ASTRONOMICAL SOURCES

    International Nuclear Information System (INIS)

    Pulliam, Robin L.; Remijan, Anthony J.; McGuire, Brett A.

    2012-01-01

    Observations of 14 rotational transitions of hydroxylamine (NH 2 OH) using the NRAO 12 m telescope on Kitt Peak are reported toward IRC+10216, Orion KL, Orion S, Sgr B2(N), Sgr B2(OH), W3IRS5, and W51M. Although recent models suggest the presence of NH 2 OH in high abundance, these observations resulted in non-detection. Upper limits are calculated to be as much as six orders of magnitude lower than those predicted by models. Possible explanations for the lower-than-expected abundance are explored.

  17. Synthesis of Hydroxysodalite From Paper Sludge Ash Using NaOH-LiOH Mixtures

    Directory of Open Access Journals (Sweden)

    Takaaki Wajima

    2017-06-01

    Full Text Available Hydroxysodalite zeolite was synthesized at 90 oC from paper sludge ash, which is industrial wastes in paper manufacturing, using NaOH-LiOH mixed solution. Paper sludge ash was discharged from paper making plant as industrial wastes, and the amount is increasing annually. The new utilization of paper sludge ash is desired. Hydroxysodalite can be used to remove HCl gas at high temperature, and there are papers for hydroxysodalite synthesis from various ashes, for example, coal fly ash. In my previous study, hydroxysodalite can be synthesized from paper sludge ash. However, little information can be available on the synthesis of hydroxysodalite from paper sludge ash. Therefore, we attempted to examine the synthesis of hydroxysodalite from paper sludge ash using NaOH-LiOH mixtures. Hydroxysodalite [Na6Al6Si6O24‧8H2O] was obtained in the mixed solution with Li / (Li + Na ratios smaller than 0.25, while katoite [Ca3Al2(SiO4(OH8] was formed in the mixed solutions with the other molar ratios, due to the dissolution of gehlenite [Ca2Al2SiO7]. The observed concentrations of Si and Al in the solution during the reaction explain the synthesis of reaction products, which depends on alkali species.

  18. Observations and model calculations of B747 engine exhaust products at cruise altitude and inferred initial OH emissions

    Energy Technology Data Exchange (ETDEWEB)

    Tremmel, H.G.; Schlager, H.; Konopka, P.; Schulte, P. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Physik der Atmosphaere; Arnold, F.; Klemm, M.; Droste-Franke, B. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany)

    1997-06-01

    NO{sub y} (NO, HNO{sub 2} and HNO{sub 3}) exhaust emissions in the near-field plume of two B747 jet airliners cruising in the upper troposphere were measured in situ using the DLR Falcon research aircraft. In addition CO{sub 2} was measured providing exhaust plume dilution rates for the species. The observations were used to estimate the initial OH concentration and NO{sub 2}/NO{sub x} ratio at the engine exit and the combustor exit by back calculations using a chemistry box model. From the two different plume events, and using two different model simulation modes in each case, we inferred OH emission indices EI(OH) = 0.32-0.39 g/kg fuel (OH{sub 0} = 9-14.4 ppmv) and (NO{sub 2}/NO{sub x}){sub 0} = 0.12-0.17. Furthermore, our results indicate that the chemistry of the exhaust species during the short period between the combustion chamber exit and the engine exit must be considered, because OH is already consumed to a great extent in this engine section, due to conversion to HNO{sub 2} and HNO{sub 3}. For the engines discussed here, the modeled OH concentration between combustor exit und engine exit decreases by a factor of about 350, leading to OH concentrations of 1-2.10{sup 12} molec/cm{sup 3} at the engine exit. (orig.) 45 refs.

  19. Variability of OH(3-1) and OH(6-2) emission altitude and volume emission rate from 2003 to 2011

    Science.gov (United States)

    Teiser, Georg; von Savigny, Christian

    2017-08-01

    In this study we report on variability in emission rate and centroid emission altitude of the OH(3-1) and OH(6-2) Meinel bands in the terrestrial nightglow based on spaceborne nightglow measurements with the SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) instrument on the Envisat satellite. The SCIAMACHY observations cover the time period from August 2002 to April 2012 and the nighttime observations used in this study are performed at 10:00 p.m. local solar time. Characterizing variability in OH emission altitude - particularly potential long-term variations - is important for an appropriate interpretation of ground-based OH rotational temperature measurements, because simultaneous observations of the vertical OH volume emission rate profile are usually not available for these measurements. OH emission altitude and vertically integrated emission rate time series with daily resolution for the OH(3-1) band and monthly resolution for the OH(6-2) band were analyzed using a standard multilinear regression approach allowing for seasonal variations, QBO-effects (Quasi-Biennial Oscillation), solar cycle (SC) variability and a linear long-term trend. The analysis focuses on low latitudes, where SCIAMACHY nighttime observations are available all year. The dominant sources of variability for both OH emission rate and altitude are the semi-annual and annual variations, with emission rate and altitude being highly anti-correlated. There is some evidence for a 11-year solar cycle signature in the vertically integrated emission rate and in the centroid emission altitude of both the OH(3-1) and OH(6-2) bands.

  20. Hyperfine excitation of OH+ by H

    Science.gov (United States)

    Lique, François; Bulut, Niyazi; Roncero, Octavio

    2016-10-01

    The OH+ ions are widespread in the interstellar medium and play an important role in the interstellar chemistry as they act as precursors to the H2O molecule. Accurate determination of their abundance rely on their collisional rate coefficients with atomic hydrogen and electrons. In this paper, we derive OH+-H fine and hyperfine-resolved rate coefficients by extrapolating recent quantum wave packet calculations for the OH+ + H collisions, including inelastic and exchange processes. The extrapolation method used is based on the infinite order sudden approach. State-to-state rate coefficients between the first 22 fine levels and 43 hyperfine levels of OH+ were obtained for temperatures ranging from 10 to 1000 K. Fine structure-resolved rate coefficients present a strong propensity rule in favour of Δj = ΔN transitions. The Δj = ΔF propensity rule is observed for the hyperfine transitions. The new rate coefficients will help significantly in the interpretation of OH+ spectra from photon-dominated region (PDR), and enable the OH+ molecule to become a powerful astrophysical tool for studying the oxygen chemistry.

  1. Spatial distribution of FIR rotationally excited CH+ and OH emission lines in the Orion Bar PDR.

    Science.gov (United States)

    Parikka, A; Habart, E; Bernard-Salas, J; Goicoechea, J R; Abergel, A; Pilleri, P; Dartois, E; Joblin, C; Gerin, M; Godard, B

    2017-03-01

    The methylidyne cation (CH + ) and hydroxyl (OH) are key molecules in the warm interstellar chemistry, but their formation and excitation mechanisms are not well understood. Their abundance and excitation are predicted to be enhanced by the presence of vibrationally excited H 2 or hot gas (~500-1000 K) in photodissociation regions with high incident FUV radiation field. The excitation may also originate in dense gas (> 10 5 cm -3 ) followed by nonreactive collisions with H 2 , H, and electrons. Previous observations of the Orion Bar suggest that the rotationally excited CH + and OH correlate with the excited CO, a tracer of dense and warm gas, and formation pumping contributes to CH + excitation. Our goal is to examine the spatial distribution of the rotationally excited CH + and OH emission lines in the Orion Bar in order to establish their physical origin and main formation and excitation mechanisms. We present spatially sampled maps of the CH + J=3-2 transition at 119.8 µm and the OH Λ-doublet at 84 µm in the Orion Bar over an area of 110″×110″ with Herschel (PACS). We compare the spatial distribution of these molecules with those of their chemical precursors, C + , O and H 2 , and tracers of warm and dense gas (high-J CO). We assess the spatial variation of CH + J=2-1 velocity-resolved line profile at 1669 GHz with Herschel HIFI spectrometer observations. The OH and especially CH + lines correlate well with the high-J CO emission and delineate the warm and dense molecular region at the edge of the Bar. While notably similar, the differences in the CH + and OH morphologies indicate that CH + formation and excitation are strongly related to the observed vibrationally excited H 2 . This, together with the observed broad CH + line widths, indicates that formation pumping contributes to the excitation of this reactive molecular ion. Interestingly, the peak of the rotationally excited OH 84 µm emission coincides with a bright young object, proplyd 244

  2. Topologically identical, but geometrically isomeric layers in hydrous α-, β-Rb[UO2(AsO3OH)(AsO2(OH)2)]·H2O and anhydrous Rb[UO2(AsO3OH)(AsO2(OH)2)

    International Nuclear Information System (INIS)

    Yu, Na; Klepov, Vladislav V.; Villa, Eric M.; Bosbach, Dirk; Suleimanov, Evgeny V.; Depmeier, Wulf; Albrecht-Schmitt, Thomas E.; Alekseev, Evgeny V.

    2014-01-01

    The hydrothermal reaction of uranyl nitrate with rubidium nitrate and arsenic (III) oxide results in the formation of polymorphic α- and β-Rb[UO 2 (AsO 3 OH)(AsO 2 (OH) 2 )]·H 2 O (α-, β-RbUAs) and the anhydrous phase Rb[UO 2 (AsO 3 OH)(AsO 2 (OH) 2 )] (RbUAs). These phases were structurally, chemically and spectroscopically characterized. The structures of all three compounds are based upon topologically identical, but geometrically isomeric layers. The layers are linked with each other by means of the Rb cations and hydrogen bonding. Dehydration experiments demonstrate that water deintercalation from hydrous α- and β-RbUAs yields anhydrous RbUAs via topotactic reactions. - Graphical abstract: Three different layer geometries observed in the structures of Rb[UO 2 (AsO 3 OH)(AsO 2 (OH) 2 )] and α- and β- Rb[UO 2 (AsO 3 OH)(AsO 2 (OH) 2 )]·H 2 O. Two different coordination environments of uranium polyhedra (types I and II) are shown schematically on the top of the figure. - Highlights: • Three new uranyl arsenates were synthesized from the hydrothermal reactions. • The phases consist of the topologically identical but geometrically different layers. • Topotactic transitions were observed in the processes of mono-hyrates dehydration

  3. OH/IR stars in the Galaxy

    International Nuclear Information System (INIS)

    Baud, B.

    1978-01-01

    Radio astronomical observations leading to the discovery of 71 OH/IR sources are described in this thesis. These OH/IR sources are characterized by their double peaked OH emission profile at a wavelength of 18 cm and by their strong IR infrared emission. An analysis of the distribution and radial velocities of a number of previously known and new OH/IR sources was performed. The parameter ΔV (the velocity separation between two emission peaks of the 18 cm line profile) was found to be a good criterion for a population classification with respect to stellar age

  4. Atmospheric fate of a series of carbonyl nitrates: photolysis frequencies and OH-oxidation rate constants.

    Science.gov (United States)

    Suarez-Bertoa, R; Picquet-Varrault, B; Tamas, W; Pangui, E; Doussin, J-F

    2012-11-20

    Multifunctional organic nitrates are potential NO(x) reservoirs whose atmospheric chemistry is somewhat little known. They could play an important role in the spatial distribution of reactive nitrogen species and consequently in ozone formation and distribution in remote areas. In this work, the rate constants for the reaction with OH radical and the photolysis frequencies of α-nitrooxyacetone, 3-nitrooxy-2-butanone, and 3-methyl-3-nitrooxy-2-butanone have been determined at room temperature at 1000 mbar total pressure of synthetic air. The rate constants for the OH oxidation were measured using the relative rate technique, with methanol as reference compound. The following rate constants were obtained for the reaction with OH: k(OH) = (6.7 ± 2.5) × 10(-13) cm(3) molecule(-1) s(-1) for α-nitrooxyacetone, (10.6 ± 4.1) × 10(-13) cm(3) molecule(-1) s(-1) for 3-nitrooxy-2-butanone, and (2.6 ± 0.9) × 10(-13) cm(3) molecule(-1) s(-1) for 3-methyl-3-nitrooxy-2-butanone. The corresponding photolysis frequencies extrapolated to typical atmospheric conditions for July first at noon at 40° latitude North were (4.8 ± 0.3) × 10(-5) s(-1), (5.7 ± 0.3) × 10(-5) s(-1), and (7.4 ± 0.2) × 10(-5) s(-1), respectively. The data show that photolysis is a major atmospheric sink for these organic nitrates.

  5. Oral Conditioned Cues Can Enhance or Inhibit Ethanol (EtOH)-Seeking and EtOH-Relapse Drinking by Alcohol-Preferring (P) Rats.

    Science.gov (United States)

    Knight, Christopher P; Hauser, Sheketha R; Deehan, Gerald A; Toalston, Jamie E; McBride, William J; Rodd, Zachary A

    2016-04-01

    Conditioned cues can elicit drug-seeking in both humans and rodents. The majority of preclinical research has employed excitatory conditioned cues (stimuli present throughout the availability of a reinforcer), but oral consumption of alcohol is similar to a conditional stimuli (presence of stimuli is paired with the delivery of the reinforcer) approach. The current experiments attempted to determine the effects of conditional stimuli (both excitatory and inhibitory) on the expression of context-induced ethanol (EtOH)-seeking. Alcohol-preferring (P) rats self-administered EtOH and water in standard 2-lever operant chambers. A flavor was added to the EtOH solution (CS+) during the EtOH self-administration sessions. After 10 weeks, rats underwent extinction training (7 sessions), followed by a 2-week home cage period. Another flavor was present during extinction (CS-). Rats were exposed to a third flavor in a non-drug-paired environment (CS(0)). EtOH-seeking was assessed in the presence of no cue, CS+, CS-, or CS(0) in the dipper previously associated with EtOH self-administration (no EtOH available). Rats were maintained a week in their home cage before being returned to the operant chambers with access to EtOH (flavored with no cue, CS+, CS-, or CS(0)). The results indicated that the presence of the CS+ enhanced EtOH-seeking, while the presence of the CS- suppressed EtOH-seeking. Similarly, adding the CS- flavor to 15% EtOH reduced responding for EtOH while the CS+ enhanced responding for EtOH during relapse testing. Overall, the data indicate that conditional stimuli are effective at altering both EtOH-seeking behavior and EtOH-relapse drinking. Copyright © 2016 by the Research Society on Alcoholism.

  6. Pharmacokinetics of 1,25(OH)(2)D(3) and 1alpha(OH)D(3) in normal and uraemic men

    DEFF Research Database (Denmark)

    Brandi, Lisbet; Egfjord, Martin; Olgaard, Klaus

    2002-01-01

    ,25(OH)(2)D(3) (n=6) protocol. RESULTS: After oral administration of 1,25(OH)(2)D(3) the bioavailability of 1,25(OH)(2)D(3) was 70.6+/-5.8/72.2+/-4.8% in healthy volunteers/uraemic patients (n.s.). After i.v. administration the volume of distribution of 1,25(OH)(2)D(3) was similar, 0.49+/-0.14 vs 0...

  7. Autoclave corrosion of zircaloy-4 cladding samples in LiOH solutions

    International Nuclear Information System (INIS)

    Hermann, A.

    2010-03-01

    In reactor operation, pH of the cooling water is adjusted by addition of alkaline hydroxides, and LiOH has been found to be the most suitable one. The addition of LiOH above a certain concentration level (depending on temperature) increases the corrosion rate of zirconium and its alloys. Hydrogen pick-up by the metal is also increased, and this effect is used to produce hydrided specimens for different investigations using the corrosion reaction. At the Paul Scherrer Institute several projects were accomplished to investigate the influence of hydrogen in Zircaloy cladding on its mechanical properties. In order to produce hydrided specimens for comparison and for adjusting new equipment, Zircaloy tubing samples were hydrogen charged by autoclave corrosion in lithiated water. Results of the corrosion experiments are outlined in this publication. Because of the great variety of possible experimental parameters these results are still of interest for the scientific community. Autoclave corrosion was accomplished in 0.2 M or 0.5 M LiOH solution at a constant temperature of 340 o C and a pressure of 160 bar. The corrosion rate increases from 84 mg/(dm 2 d) in 0.2 M LiOH to 153 mg/(dm 2 d) in 0.5 M LiOH. The hydrogen pick-up fraction in 0.5 M LiOH amounts to 80%. In 0.5 M LiOH, Zircaloy tubing samples can be charged with ∼ 500 ppm hydrogen in about 40 hours. In the corrosion experiments described in this report a homogeneous distribution of hydrides should be expected (except very high hydride concentrations) because no temperature gradient exists through the tubing wall. Hydrogen stringers are homogeneously distributed with circumferential orientation (stress-relieved tubing samples). (author)

  8. On prediction of OH stretching frequencies in intramolecularly hydrogen bonded systems

    DEFF Research Database (Denmark)

    Hansen, Poul Erik; Spanget-Larsen, Jens

    2012-01-01

    OH stretching frequencies are investigated for a series of non-tautomerizing systems with intramolecular hydrogen bonds. Effective OH stretching wavenumbers are predicted by the application of empirical correlation procedures based on the results of B3LYP/6-31G(d) theoretical calculations...

  9. A SEARCH FOR HYDROXYLAMINE (NH{sub 2}OH) TOWARD SELECT ASTRONOMICAL SOURCES

    Energy Technology Data Exchange (ETDEWEB)

    Pulliam, Robin L.; Remijan, Anthony J. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); McGuire, Brett A. [Division of Chemistry and Chemical Engineering, California Institute of Technology Pasadena, CA 91125 (United States)

    2012-05-20

    Observations of 14 rotational transitions of hydroxylamine (NH{sub 2}OH) using the NRAO 12 m telescope on Kitt Peak are reported toward IRC+10216, Orion KL, Orion S, Sgr B2(N), Sgr B2(OH), W3IRS5, and W51M. Although recent models suggest the presence of NH{sub 2}OH in high abundance, these observations resulted in non-detection. Upper limits are calculated to be as much as six orders of magnitude lower than those predicted by models. Possible explanations for the lower-than-expected abundance are explored.

  10. OH megamasers: dense gas & the infrared radiation field

    Science.gov (United States)

    Huang, Yong; Zhang, JiangShui; Liu, Wei; Xu, Jie

    2018-06-01

    To investigate possible factors related to OH megamaser formation (OH MM, L_{H2O}>10L_{⊙}), we compiled a large HCN sample from all well-sampled HCN measurements so far in local galaxies and identified with the OH MM, OH kilomasers (L_{H2O}gas and the dense gas, respectively), we found that OH MM galaxies tend to have stronger HCN emission and no obvious difference on CO luminosity exists between OH MM and non-OH MM. This implies that OH MM formation should be related to the dense molecular gas, instead of the low-density molecular gas. It can be also supported by other facts: (1) OH MMs are confirmed to have higher mean molecular gas density and higher dense gas fraction (L_{HCN}/L_{CO}) than non-OH MMs. (2) After taking the distance effect into account, the apparent maser luminosity is still correlated with the HCN luminosity, while no significant correlation can be found at all between the maser luminosity and the CO luminosity. (3) The OH kMs tend to have lower values than those of OH MMs, including the dense gas luminosity and the dense gas fraction. (4) From analysis of known data of another dense gas tracer HCO^+, similar results can also be obtained. However, from our analysis, the infrared radiation field can not be ruled out for the OH MM trigger, which was proposed by previous works on one small sample (Darling in ApJ 669:L9, 2007). On the contrary, the infrared radiation field should play one more important role. The dense gas (good tracers of the star formation) and its surrounding dust are heated by the ultra-violet (UV) radiation generated by the star formation and the heating of the high-density gas raises the emission of the molecules. The infrared radiation field produced by the re-radiation of the heated dust in turn serves for the pumping of the OH MM.

  11. The nature of OH/IR stars

    International Nuclear Information System (INIS)

    Herman, J.

    1983-01-01

    In this work masers in evolved stars are studied, in particular the emission from the OH radical. The time variability of the OH masers was measured over a period of five years with the Dwingeloo Radio Telescope. These single-dish observations proved that most of the underlying stars are very long period variables, apparently a kind of extension of the well-known long period Mira variables. The mean OH fluxes and epochs were obtained as well as a confirmation of the radiative coupling between the maser and the star (by comparison with infrared data provided by other observers), the degree of saturation, and, most important of all, a determination of the linear dimensions of the circumstellar shells. Multi-element interferometer observations were made in order to study the spatial structure of OH masers. By combining the phase lag measurements and the spatial extent distances to individual stars could be determined with a high, unprecedented accuracy. Infrared broad-band photometry was done in the wavelength region from 3 μm to 20 μm, where most of the energy of these objects is radiated. The space density and galactic distribution of OH/IR stars are discussed and compared with the appearance of OH masers in the solar neighbourhood. (Auth.)

  12. Intercomparison of OH and OH reactivity measurements in a high isoprene and low NO environment during the Southern Oxidant and Aerosol Study (SOAS)

    Science.gov (United States)

    Sanchez, Dianne; Jeong, Daun; Seco, Roger; Wrangham, Ian; Park, Jeong-Hoo; Brune, William H.; Koss, Abigail; Gilman, Jessica; de Gouw, Joost; Misztal, Pawel; Goldstein, Allen; Baumann, Karsten; Wennberg, Paul O.; Keutsch, Frank N.; Guenther, Alex; Kim, Saewung

    2018-02-01

    We intercompare OH and OH reactivity datasets from two different techniques, chemical ionization mass spectrometry (CIMS) and laser-induced fluorescence (LIF) in a high isoprene and low NO environment in a southeastern US forest during the Southern Oxidant and Aerosol Study (SOAS). An LIF instrument measured OH and OH reactivity at the top of a tower, a CIMS instrument measured OH at the top of the tower, and a CIMS based comparative reactivity method (CRM-CIMS) instrument deployed at the base of the tower measured OH reactivity. Averaged diel variations of OH and OH reactivity from these datasets agree within analytical uncertainty and correlations of LIF versus CIMS for OH and OH reactivity have slopes of 0.65 and 0.97, respectively. However, there are systematic differences between the measurement datasets. The CRM-CIMS measurements of OH reactivity were ∼16% lower than those by the LIF technique in the late afternoon. We speculate that it is caused by losses in the sampling line down to the CRM-CIMS instrument. On the other hand, we could not come up with a reasonable explanation for the difference in the LIF and CIMS OH datasets for early morning and late afternoon when OH is below 1 × 106 molecules cm-3. Nonetheless, results of this intercomparison exercise strengthen previous publications from the field site on OH concentrations and atmospheric reactivity.

  13. Antidepressants differentially related to 1,25-(OH)₂ vitamin D₃ and 25-(OH) vitamin D₃ in late-life depression.

    Science.gov (United States)

    Oude Voshaar, R C; Derks, W J; Comijs, H C; Schoevers, R A; de Borst, M H; Marijnissen, R M

    2014-04-15

    A low plasma 25-OH vitamin D3 level is a universal risk factor for a wide range of diseases and has also been implicated in late-life depression. It is currently unknown whether the biologically active form of vitamin D, that is, 1,25-(OH)2 vitamin D3, is also decreased in late-life depression, or whether vitamin D levels correlate with specific depression characteristics. We determined plasma 25-OH vitamin D3, 1,25-(OH)2 vitamin D3 and parathormone levels in 355 depressed older persons and 124 non-depressed comparison subjects (age 60 years). Psychopathology was established with the Composite International Diagnostic Interview 2.1, together with potential confounders and depression characteristics (severity, symptom profile, age of onset, recurrence, chronicity and antidepressant drug use). Adjusted for confounders, depressed patients had significantly lower levels of 25-OH vitamin D33 (Cohen's d =0.28 (95% confidence interval: 0.07-0.49), P=0.033) as well as 1,25-(OH)2 vitamin D3 (Cohen's d =0.48 (95% confidence interval: 0.27-0.70), Pdepression characteristics tested, only the use of tricyclic antidepressants (TCAs) was significantly correlated with lower 1,25-(OH)2 vitamin D3 levels (Cohen's d =0.86 (95% confidence interval: 0.53-1.19), Pprecursor 25-OH vitamin D3. As vitamin D levels were significantly lower after adjustment for confounders, vitamin D might have an aetiological role in late-life depression. Differences between depressed and non-depressed subjects were largest for the biologically active form of vitamin D. The differential impact of TCAs on 25-OH vitamin D3 and 1,25-(OH)2 vitamin D3 levels suggests modulation of 1-α-hydroxylase and/or 24-hydroxylase, which may in turn have clinical implications for biological ageing mechanisms in late-life depression.

  14. Zinc-zincate electrochemical behaviour in NaOH medium

    International Nuclear Information System (INIS)

    Pessine, E.J.

    1984-01-01

    The reaction mechanism of zinc/NaOH-zincate system was investigated with the rotating disk electrode technique, using both the surfaces of mercury film and zinc in 1M NaOH concentration and 25 0 C temperature. It was found that, at the mercury surface, the zincate ion deposition reaction occurs by two steps with one electron each, with comparable rates, with b sup(-) sub(K1) = (132+ -20)mV/decade and b sup(-) sub(K2) = (74 + - 9)mV/decade cathodic Tafel slopes. At the zinc surface the mechanism of the anodic and cathodic reactions is the same and is by two steps with one electron each. The rate-determining step is the first reaction in the cathodic direction. The exchange current density was found to be between 1.00 and 6.00mA/cm 2 , with b sup(-) sub(K) = (95+ -3)mV/decade cathodic and b sup(-) sub(a) = (61+ -5)mV/decade anodic Tafel slopes. The mechanism of passivation of zinc occurs as a result of the two reactions, the adsorption of the dissolved species of zinc II and the precipitation of the zincate ions over the electrode active sites. It has been verified that of all the chemical species studied namely the zincate, chloride, benzoate, silicate ions and the benzotriazole that affect the zinc anodic reaction the silicate ion is the one that change the reaction rate. However, for all the species studied we have the same anodic reaction mechanism (active dissolution). The deposition reaction mechanism of the zincate ion on zinc electrode is the same with NaOH plus benzoate or chloride. The diffusion coefficient found for the diffusion of the zincate ion in 1M NaOH with the mercury film RDE is D sup(-) = (4,90+ -0,20) x 10 -6 cm 2 s -1 . (Author) [pt

  15. OH radiation from the interstellar cloud medium

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen-Q-Rieu,; Winnberg, A [Max-Planck-Institut fuer Radioastronomie, Bonn (F.R. Germany); Guibert, J [Observatoire de Paris, Section de Meudon, 92 (France); Lepine, J R.D. [Universidade Mackenzie, Sao Paulo (Brazil). Centro de Radio-Astronomia et Astrofisica; Johansson, L E.B. [Rymdobservatoriet, Onsala (Sweden); Goss, W M [Commonwealth Scientific and Industrial Research Organization, Epping (Australia). Div. of Radiophysics

    1976-02-01

    We have detected OH in the direction of about 50% of the continuum sources investigated. The OH abundance is one order of magnitude less than usually found in dust clouds. Most of the OH features have HI counterparts. This suggests that the OH radiation arises from the HI interstellar cold clouds. Our observations allowed in some cases the determination of the excitation temperatures in all four lines. A pumping model involving far-infrared radiation and collisions with neutral and charged particles has been proposed. It explains the observed excitation temperatures.

  16. Topologically identical, but geometrically isomeric layers in hydrous α-, β-Rb[UO2(AsO3OH)(AsO2(OH)2)]·H2O and anhydrous Rb[UO2(AsO3OH)(AsO2(OH)2)

    Science.gov (United States)

    Yu, Na; Klepov, Vladislav V.; Villa, Eric M.; Bosbach, Dirk; Suleimanov, Evgeny V.; Depmeier, Wulf; Albrecht-Schmitt, Thomas E.; Alekseev, Evgeny V.

    2014-07-01

    The hydrothermal reaction of uranyl nitrate with rubidium nitrate and arsenic (III) oxide results in the formation of polymorphic α- and β-Rb[UO2(AsO3OH)(AsO2(OH)2)]·H2O (α-, β-RbUAs) and the anhydrous phase Rb[UO2(AsO3OH)(AsO2(OH)2)] (RbUAs). These phases were structurally, chemically and spectroscopically characterized. The structures of all three compounds are based upon topologically identical, but geometrically isomeric layers. The layers are linked with each other by means of the Rb cations and hydrogen bonding. Dehydration experiments demonstrate that water deintercalation from hydrous α- and β-RbUAs yields anhydrous RbUAs via topotactic reactions.

  17. Enhancing anaerobic digestion of waste activated sludge by the combined use of NaOH and Mg(OH)2: Performance evaluation and mechanism study.

    Science.gov (United States)

    Huang, Cheng; Lai, Jia; Sun, Xiuyun; Li, Jiansheng; Shen, Jinyou; Han, Weiqing; Wang, Lianjun

    2016-11-01

    In this study, the combination treatment of NaOH and Mg(OH)2 was applied to anaerobic digestion of waste activated sludge (WAS) for simultaneously enhancement of volatile fatty acids (VFAs) production, nutrients removal and sludge dewaterability. The maximum VFAs production (461mg COD/g VSS) was obtained at the NaOH/Mg(OH)2 ratio of 75:25, which was much higher than that of the blank or sole NaOH. Moreover, nutrients removal and sludge dewaterability were improved by the combined using of NaOH and Mg(OH)2. Mechanism investigations revealed that the presence of Mg(OH)2 could maintain alkaline environment, which contributed to inhibit the activity of methanogens. Also, the bridging between Mg(2+) and extracellular polymeric substances (EPS) plays an important role in the solubilization and dewatering of sludge. High-throughput sequencing analysis demonstrated that the abundance of bacteria involved in sludge hydrolysis and VFAs accumulation was greatly enriched with the mixtures of NaOH and Mg(OH)2. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Biodistribution and tumor uptake of C{sub 60}(OH){sub x} in mice

    Energy Technology Data Exchange (ETDEWEB)

    Zhiqiang, Ji; Sun Hongfang, E-mail: shf@pku.edu.cn; Haifang, Wang; Qunying, Xie; Yuangfang, Liu [Peking University, Department of Chemical Biology, College of Chemistry and Molecular Engineering (China); Zheng, Wang [Chinese Academy of Medical Sciences, Cancer Institute (China)

    2006-02-15

    Radiolabeling of fullerol, {sup 125}I-C{sub 60}(OH){sub x}, was performed by the traditional chloramine-T method. The C-I covalent bond in I-C{sub 60}(OH){sub x} was characterized by X-ray photoelectron spectroscopy (XPS) that was sufficiently stable for in vivo study. Laser light scattering spectroscopy clearly showed that C{sub 60}(OH){sub x} aggregated to large nanoparticle clumps with a wide range of distribution. The clumps formed were also visualized by transmission electron microscope (TEM). We examined the biodistribution and tumor uptake of C{sub 60}(OH){sub x} in five mouse bearing tumor models, including mouse H22 hepatocarcinoma, human lung giantcellcarcinoma PD, human colon cancer HCT-8, human gastric cancer MGC803, and human OS732 osteosarcoma. The accumulation ratios of {sup 125}I-C{sub 60}(OH){sub x} in mouse H22 hepatocarcinoma to that in normal muscle tissue (T/N) and blood (T/B) at 1, 6, 24 and 72 h, reveal that {sup 125}I-C{sub 60}(OH){sub x} gradually accumulates in H22 tumor, and retains for a quite long period (e.g., T/N 3.41, T/B 3.94 at 24 h). For the other four tumor models, the T/N ratio at 24 h ranges within 1.21-6.26, while the T/B ratio ranges between 1.23 and 4.73. The accumulation of C{sub 60}(OH){sub x} in tumor is mostly due to the enhanced permeability and retention effect (EPR) and the phagocytosis of mononuclear phagocytes. Hence, C{sub 60}(OH){sub x} might serve as a photosensitizer in the photodynamic therapy of some kinds of tumor.

  19. Methanol oxidation in a flow reactor: Implications for the branching ratio of the CH3OH+OH reaction

    DEFF Research Database (Denmark)

    Rasmussen, Christian Lund; Wassard, K.H.; Dam-Johansen, Kim

    2008-01-01

    The oxidation of methanol in a flow reactor has been studied experimentally under diluted, fuel-lean conditions at 650-1350 K, over a wide range of O-2 concentrations (1%-16%), and with and without the presence of nitric oxide. The reaction is initiated above 900 K, with the oxidation rate...... decreasing slightly with the increasing O-2 concentration. Addition of NO results in a mutually promoted oxidation of CH3OH and NO in the 750-1100 K range. The experimental results are interpreted in terms of a revised chemical kinetic model. Owing to the high sensitivity of the mutual sensitization of CH3OH...... and NO oxidation to the partitioning of CH3O and CH2OH, the CH3OH + OH branching fraction could be estimated as alpha = 0.10 +/- 0.05 at 990 K. Combined with low-temperature measurements, this value implies a branching fraction that is largely independent of temperature. It is in good agreement with recent...

  20. Measurements of total OH reactivity during PROPHET-AMOS 2016

    Science.gov (United States)

    Rickly, P.; Sakowski, J.; Bottorff, B.; Lew, M.; Stevens, P. S.; Sklaveniti, S.; Locoge, N.; Dusanter, S.

    2017-12-01

    As one of the main oxidant in the atmosphere, the hydroxyl radical (OH) initiates the oxidation of volatile organic compounds that can lead to the formation of ozone and secondary organic aerosols. Understanding both the sources and sinks of OH is therefore important to address issues related to air quality and climate change. Measurements of total OH reactivity can provide an important test of our understanding of the OH radical budget. Recent measurements of total reactivity in many environments have been greater than calculated based on the measured concentration of VOCs, suggesting that important OH sinks in these environments are not well characterized. Measurements of total OH reactivity were performed in a forested environment during the PROPHET - AMOS field campaign (Program for Research on Oxidants: PHotochemisty, Emissions, and Transport - Atmospheric Measurements of Oxidants in Summer) using the Comparative Reactivity Method (CRM) and the Total OH Loss Rate Method (TOHLM). The site is characterized by large emissions of isoprene and monoterpenes and low anthropogenic influence. Measurements of total OH reactivity using these two techniques agree to within their respective uncertainties, giving confidence in the measured OH reactivity. In addition, measurements of trace gases (VOCs, NOx, O3) were used to perform a comprehensive apportionment of OH sinks. These measurements are used in a chemical model using the Master Chemical Mechanism to calculate the expected OH reactivity. The results will be compared to previous measurements of total OH reactivity at this site.

  1. Crystal structures of Th(OH)PO4, U(OH)PO4 and Th2O(PO4)2. Condensation mechanism of M(IV)(OH)PO4 (M= Th, U) into M2O(PO4)2

    International Nuclear Information System (INIS)

    Dacheux, N.; Clavier, N.; Wallez, G.; Quarton, M.

    2007-01-01

    Three new crystal structures, isotypic with β-Zr 2 O(PO 4 ) 2 , have been resolved by the Rietveld method. All crystallize with an orthorhombic cell (S.G.: Cmca) with a = 7.1393(2) Angstroms, b = 9.2641(2) Angstroms, c 12.5262(4) Angstroms, V = 828.46(4) (Angstroms) 3 and Z = 8 for Th(OH)PO 4 ; a = 7.0100(2) Angstroms, b = 9.1200(2) Angstroms, c = 12.3665(3) Angstroms, V 790.60(4) (Angstroms) 3 and Z = 8 for U(OH)PO 4 ; a 7.1691(3) Angstroms, b 9.2388(4) Angstroms, c = 12.8204(7) Angstroms, V 849.15(7) (Angstroms) 3 and Z = 4 for Th 2 O(PO 4 ) 2 . By heating, the M(OH)PO 4 (M Th, U) compounds condense topotactically into M 2 O(PO 4 ) 2 , with a change of the environment of the tetravalent cation that lowers from 8 to 7 oxygen atoms. The lower stability of Th 2 O(PO 4 ) 2 compared to that of U 2 O(PO 4 ) 2 seems to result from this unusual environment for tetravalent thorium. (authors)

  2. Brief Exposures to the Taste of Ethanol (EtOH) and Quinine Promote Subsequent Acceptance of EtOH in a Paradigm that Minimizes Postingestive Consequences.

    Science.gov (United States)

    Loney, Gregory C; Meyer, Paul J

    2018-03-01

    Aversion to the orosensory properties of concentrated ethanol (EtOH) solutions is often cited as a primary barrier to initiation of drinking and may contribute to abstention. These aversive properties include gustatory processes which encompass both bitter-like taste qualities and trigeminal-mediated irritation. Chronic intermittent EtOH access (CIA) results in substantial and persistent increases in EtOH consumption, but the degree to which this facilitation involves sensory responding to EtOH and other bitter stimuli is currently undetermined. Long-Evans rats were given brief-access licking tests designed to examine the immediate, taste-guided assessment of the palatability of EtOH and quinine solutions. Rats were assessed once in a naïve state and again following previous brief-access exposure, or following 4 weeks of CIA. The relationship between the sensitivity to the aversive orosensory properties of EtOH and quinine following EtOH access and the impact of antecedent quinine exposure on the acceptance of EtOH were determined in 2 parallel studies. Both brief access to EtOH and 4-week CIA resulted in substantial rightward shifts in the concentration-response function of brief-access EtOH licking, indicating that EtOH exposure increased acceptance of the taste of EtOH. The initial sensitivity to the aversive orosensory properties of EtOH and quinine was positively correlated in naïve rats, such that rats that were initially more accepting of quinine were also more accepting of EtOH. Rats that sampled quinine immediately prior to tasting EtOH exhibited successive positive contrast in that they were more accepting of highly concentrated EtOH, relative to a water-control group. Increased EtOH acceptance following exposure is, at least in part, facilitated by a decrease in its aversive sensory properties. Both long- and short-term access increase the palatability of the taste of EtOH in brief-access licking tests. Moreover, the sensitivity to the bitterness of

  3. Infrared and Raman spectroscopic characterization of the silicate mineral olmiite CaMn2+[SiO3(OH)](OH) - implications for the molecular structure

    Science.gov (United States)

    Frost, Ray L.; Scholz, Ricardo; López, Andrés; Xi, Yunfei; Granja, Amanda; Žigovečki Gobac, Željka; Lima, Rosa Malena Fernandes

    2013-12-01

    We have studied the mineral olmiite CaMn[SiO3(OH)](OH) which forms a series with its calcium analogue poldervaartite CaCa[SiO3(OH)](OH) using a range of techniques including scanning electron microscopy, thermogravimetric analysis, Raman and infrared spectroscopy. Chemical analysis shows the mineral is pure and contains only calcium and manganese in the formula. Thermogravimetric analysis proves the mineral decomposes at 502 °C with a mass loss of 8.8% compared with the theoretical mass loss of 8.737%. A strong Raman band at 853 cm-1 is assigned to the SiO stretching vibration of the SiO3(OH) units. Two Raman bands at 914 and 953 cm-1 are attributed to the antisymmetric vibrations. Two intense Raman bands observed at 3511 and 3550 cm-1 are assigned to the OH stretching vibration of the SiO3(OH) units. The observation of multiple OH bands supports the concept of the non-equivalence of the OH units. Vibrational spectroscopy enables a detailed assessment of the molecular structure of olmiite.

  4. OH Solar Radiometer

    Data.gov (United States)

    National Aeronautics and Space Administration — The abundance of the hydroxyl radical, OH, determines the lifetime of methane and its global warming potential. Despite the growing importance of methane and the...

  5. A search for OH emission from symbiotic stars

    International Nuclear Information System (INIS)

    Norris, R.P.; Haynes, R.F.; Wright, A.E.

    1984-01-01

    A search was made for OH maser emission from a sample of 16 symbiotic stars. This sample was selected on the basis of infrared optical depth and variability, so that the stars within it have circumstellar shells similar to those seen in OH/IR and OH/Mira stars. There were no significant detections, except for one unassociated background source, and it is concluded that the presence of a hot binary companion inhibits any possible OH maser action

  6. 76 FR 2145 - Masco Builder Cabinet Group Including On-Site Leased Workers From Reserves Network, Jackson, OH...

    Science.gov (United States)

    2011-01-12

    ...,287B; TA-W-71,287C] Masco Builder Cabinet Group Including On-Site Leased Workers From Reserves Network, Jackson, OH; Masco Builder Cabinet Group, Waverly, OH; Masco Builder Cabinet Group, Seal Township, OH; Masco Builder Cabinet Group, Seaman, OH; Amended Certification Regarding Eligibility To Apply for Worker...

  7. Young planetary nebula with OH molecules - NGC 6302

    International Nuclear Information System (INIS)

    Payne, H.E.; Phillips, J.A.; Terzian, Y.

    1988-01-01

    The results of a sensitive survey of planetary nebulae in all four ground-state OH lines are reported. The results confirm that evolved planetary nebulas are not OH sources in general. However, one interesting object was not detected: an OH 1612 MHz maser in the young planetary nebula NGC 6302. This nebula may be in a brief evolutionary stage, similar to the young and compact planetary nebula Vy 2-2, where OH has already been detected. In addition, the results of further observations of NGC 6302 are reported, including VLA observations of the 1612 MHz line and continuum emission and detections of rotationally excited OH lines at 5-cm wavelength in absorption. 28 references

  8. OH detection by Ford Motor Company

    Science.gov (United States)

    Wang, Charles C.

    1986-12-01

    Two different methods for detection of OH are presented: a low pressure flow cell system and a frequency modulation absorption measurement. Using conventional absorption spectroscopy, detection limits were quoted of 1,000,000 OH molecules per cu cm using a 30-minute averaging time on the ground, and a 3-hour averaging time in the air for present apparatus in use. With the addition of FM spectroscopy at 1 GHz, a double-beam machine should permit detectable absorption of and an OH limit of 100,000 per cu cm in a 30-minute averaging time. In the low pressure system on which experiments are ongoing nonexponential time behavior was observed after the decay had progressed to about 0.3 of its original level; this was attributed to ion emission in the photomultiplier. A flame source with OH present at high concentration levels was used as a calibration. It was estimated that within the sampling chamber, 400,000 OH could be measured. With a factor-of-2 loss at the sampling orifice, this means detectability of 5 to 8 x 100,000 cu cm at the present time. This could be reduced by a factor of 2 in one hour averaging time; improvements in laser bandwidth and energy should provide another factor of 2 in sensitivity.

  9. Concentrations of OH and HO2 radicals during NAMBLEX: measurements and steady state analysis

    Directory of Open Access Journals (Sweden)

    S. C. Smith

    2006-01-01

    Full Text Available OH and HO2 concentrations were measured simultaneously at the Mace Head Atmospheric Research Station in the summer of 2002 during the NAMBLEX (North Atlantic Marine Boundary Layer EXperiment field campaign. OH was measured by laser-induced fluorescence employing the FAGE (Fluorescence Assay by Gas Expansion technique, with a mean daytime detection limit of 2.7×105 molecule cm−3 (5 min acquisition period; signal-to-noise ratio = 1. HO2 was detected as OH following its chemical conversion through addition of NO, with a mean detection limit of 4.4×106 molecule cm−3. The diurnal variation of OH was measured on 24 days, and that of HO2 on 17 days. The local solar noon OH concentrations ranged between (3–8×106 molecule cm−3, with a 24 h mean concentration of 9.1×105 molecule cm−3. The local solar noon HO2 concentrations were (0.9–2.1×108 molecule cm−3 (3.5–8.2 pptv, with a 24 h mean concentration of 4.2×107 molecule cm−3 (1.6 pptv. HO2 radicals in the range (2–3×107 molecule cm−3 were observed at night. During NAMBLEX, a comprehensive suite of supporting measurements enabled a detailed study of the behaviour of HOx radicals under primarily clean marine conditions. Steady state expressions are used to calculate OH and HO2 concentrations and to evaluate the effect of different free-radical sources and sinks. The diurnally averaged calculated to measured OH ratio was 1.04±0.36, but the ratio displays a distinct diurnal variation, being less than 1 during the early morning and late afternoon/evening, and greater than 1 in the middle of the day. For HO2 there was an overprediction, with the agreement between calculated and measured concentrations improved by including reaction with measured IO and BrO radicals and uptake to aerosols. Increasing the concentration of IO radicals included in the calculations to above that measured by a DOAS instrument with an absorption path located mainly over the ocean, reflecting the

  10. OH outflows in star-forming regions

    International Nuclear Information System (INIS)

    Mirabel, I.F.; Ruiz, A.; Rodriguez, L.F.; Canto, J.; Universidad de Puer; Universidad de Puerto Rico, Rio Piedras; Universidad Nacional Autonoma de Mexico, Mexico City)

    1987-01-01

    The results from a survey for high-velocity OH in molecular outflows in star-forming regions are reported. High-velocity OH was detected in absorption in nine of these regions. When the telescope beam can resolve the outflows, they show similar anisotropic angular distribution as the redshifted and blueshifted CO. The OH transitions are markedly subthermal since for several sources it is found that the radiation that is being absorbed is a background continuum constituted by the cosmic component plus a small Galactic contribution. The absorbing OH appears to trace gas with higher velocities and lower densities than does the CO and, in some cases, provides information on the structure of the outflows at larger distances from the central source. At scales of 0.1 pc, the outflows are elongated in the direction of the steepest density gradient of the ambient cloud, suggesting that the large-scale collimation of the outflow is produced by the density structure of the ambient cloud. 29 references

  11. Optimization and kinetics decomposition of monazite using NaOH

    International Nuclear Information System (INIS)

    MV Purwani; Suyanti; Deddy Husnurrofiq

    2015-01-01

    Decomposition of monazite with NaOH has been done. Decomposition performed at high temperature on furnace. The parameters studied were the comparison NaOH / monazite, temperature and time decomposition. From the research decomposition for 100 grams of monazite with NaOH, it can be concluded that the greater the ratio of NaOH / monazite, the greater the conversion. In the temperature influences decomposition 400 - 700°C, the greater the reaction rate constant with increasing temperature greater decomposition. Comparison NaOH / monazite optimum was 1.5 and the optimum time of 3 hours. Relations ratio NaOH / monazite with conversion (x) following the polynomial equation y = 0.1579x 2 – 0.2855x + 0.8301 (y = conversion and x = ratio of NaOH/monazite). Decomposition reaction of monazite with NaOH was second orde reaction, the relationship between temperature (T) with a reaction rate constant (k), k = 6.106.e - 1006.8 /T or ln k = - 1006.8/T + 6.106, frequency factor A = 448.541, activation energy E = 8.371 kJ/mol. (author)

  12. CSO and CARMA Observations of L1157. I. A Deep Search for Hydroxylamine (NH2OH)

    Science.gov (United States)

    McGuire, Brett A.; Carroll, P. Brandon; Dollhopf, Niklaus M.; Crockett, Nathan R.; Corby, Joanna F.; Loomis, Ryan A.; Burkhardt, Andrew M.; Shingledecker, Christopher; Blake, Geoffrey A.; Remijan, Anthony J.

    2015-10-01

    A deep search for the potential glycine precursor hydroxylamine (NH2OH) using the Caltech Submillimeter Observatory (CSO) at λ = 1.3 mm and the Combined Array for Research in Millimeter-wave Astronomy at λ = 3 mm is presented toward the molecular outflow L1157, targeting the B1 and B2 shocked regions. We report non-detections of NH2OH in both sources. We perform a non-LTE analysis of CH3OH observed in our CSO spectra to derive the kinetic temperatures and densities in the shocked regions. Using these parameters, we derive upper limit column densities of NH2OH of ≤1.4 × 1013 cm-2 and ≤1.5 × 1013 cm-2 toward the B1 and B2 shocks, respectively, and upper limit relative abundances of {N}{{NH}2{OH}}/{N}{{{H}}2}≤slant 1.4× {10}-8 and ≤1.5 × 10-8, respectively.

  13. Cross-section and rate coefficient calculation for electron impact excitation, ionisation and dissociation of H2 and OH molecules

    International Nuclear Information System (INIS)

    Riahi, R.; Ben Lakhdar, Z.; Teulet, Ph.; Gleizes, A.

    2006-01-01

    The weighted total cross-sections (WTCS) theory is used to calculate electron impact excitation, ionization and dissociation cross-sections and rate coefficients of OH, H 2 , OH + , H 2 + , OH - and H 2 - diatomic molecules in the temperature range 1500-15000 K. Calculations are performed for H 2 (X, B, C), OH(X, A, B), H 2 + (X), OH + (X, a, A, b, c), H 2 - (X) and OH - (X) electronic states for which Dunham coefficients are available. Rate coefficients are calculated from WTCS assuming Maxwellian energy distribution functions for electrons and heavy particles. One and 2 temperatures (θ e and θ g respectively for electron and heavy particles kinetic temperatures) results are presented and fitting parameters (a, b and c) are given for each reaction rate coefficient: k(θ) a(θ b )exp(-c/θ). (authors)

  14. Interactions between kaolinite Al−OH surface and sodium hexametaphosphate

    Energy Technology Data Exchange (ETDEWEB)

    Han, Yonghua, E-mail: hyh19891102@163.com [School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing 100083 (China); Liu, Wenli; Zhou, Jia [School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing 100083 (China); Chen, Jianhua [College of Resources and Metallurgy, Guangxi University, Nanning 530004 (China)

    2016-11-30

    Highlights: • Sodium hexametaphosphate (NaHMP) can adsorb on kaolinite Al−OH terminated (001) surface easily. • The oxygen atoms of hexametaphosphate form strong hydrogen bonds with the hydrogen atoms of kaolinite Al−OH surface. • The electrostatic force is the main interaction between NaHMP and Al−OH surface. • The linear hexaphosphate −[PO{sub 3}]{sub m}− chains adsorb stably than −[HPO{sub 3}]{sub m}− chains. - Abstract: To investigate the dispersion mechanism of sodium hexametaphosphate on kaolinite particles, we simulated the interaction between linear polyphosphate chains and kaolinite Al−OH terminated surface by molecular dynamics, as well as the interaction between the [HPO{sub 4}]{sup 2−} anion and kaolinite Al−OH surface by density functional theory (DFT). The calculated results demonstrate that hexametaphosphate can be adsorbed by the kaolinite Al−OH surface. The oxygen atoms of hexametaphosphate anions may receive many electrons from the Al−OH surface and form hydrogen bonds with the hydrogen atoms of surface hydroxyl groups. Moreover, electrostatic force dominates the interactions between hexametaphosphate anions and kaolinite Al−OH surface. Therefore, after the adsorption of hexametaphosphate on kaolinite Al−OH surface, the kaolinite particles carry more negative charge and the electrostatic repulsion between particles increases. In addition, the adsorption of −[PO{sub 3}]{sub m}− species on the Al−OH surface should be more stable than the adsorption of −[HPO{sub 3}]{sub m}− species.

  15. Radioimmunoassay of free urinary 18-hydroxydeoxycorticosterone (18-OH-DOC) in patients with essential hypertension

    International Nuclear Information System (INIS)

    Hornung, J.; Gless, K.H.; Abdelhamid, S.; Vielhauer, W.; Vecsei, P.

    1978-01-01

    Specific antiserum was raised in white New Zealand rabbits using 18-hydroxydeoxycorticosterone-3-oxime-BSA complex as antigen. The urinary free 18-OH-DOC was estimated after dichloromethane extraction and separation in one paper chromatographic system (propylene glycol/toluene). The mean 18-OH-DOC excretion value (+-S.D.) in normal subjects was 0.861+-0.527 μg/24 h (n=23). ACTH produced a 25-fold increase in the excretion of free 18-OH-DOC. Dexamethasone suppressed the values to the lower range of sensitivity. 32% of patients of essential hypertension showed a moderate increase in the free urinary 18-OH-DOC values. The mean value (+-S.D.) in the low renin hypertension group was 2.50 +- 1.49 μg/24 h (n=19), in the normal renin patient group 1.84 +- 1.32 μg/24 h (n=38), and in the group with elevated plasma renin 1.61 +- 1.22 μg/24 h (n=8). The difference between controls and the hypertensive groups was statistically significant. Among the different hypertensive groups significant differences could not be calculated. (Auth.)

  16. Crystal structure, equation of state, and elasticity of hydrous aluminosilicate phase, topaz-OH (Al2SiO4(OH)2) at high pressures

    Science.gov (United States)

    Mookherjee, Mainak; Tsuchiya, Jun; Hariharan, Anant

    2016-02-01

    We examined the equation of state and high-pressure elasticity of the hydrous aluminosilicate mineral topaz-OH (Al2SiO4(OH)2) using first principles simulation. Topaz-OH is a hydrous phase in the Al2O3-SiO2-H2O (ASH) ternary system, which is relevant for the mineral phase relations in the hydrated sedimentary layer of subducting slabs. Based on recent neutron diffraction experiments, it is known that the protons in the topaz-OH exhibit positional disorder with half occupancy over two distinct crystallographic sites. In order to adequately depict the proton environment in the topaz-OH, we examined five crystal structure models with distinct configuration for the protons in topaz-OH. Upon full geometry optimization we find two distinct space group, an orthorhombic Pbnm and a monoclinic P21/c for topaz-OH. The topaz-OH with the monoclinic P21/c space group has a lower energy compared to the orthorhombic Pbmn space group symmetry. The pressure-volume results for the monoclinic topaz-OH is well represented by a third order Birch-Murnaghan formulation, with V0mon = 348.63 (±0.04) Å3, K0mon = 164.7 (±0.04) GPa, and K0mon = 4.24 (±0.05). The pressure-volume results for the orthorhombic topaz-OH is well represented by a third order Birch-Murnaghan formulation, with V0orth = 352.47 (±0.04) Å3, K0orth = 166.4 (±0.06) GPa, and K0orth = 4.03 (±0.04). While the bulk moduli are very similar for both the monoclinic and orthorhombic topaz-OH, the shear elastic constants and the shear moduli are very sensitive to the position of the proton, orientation of the O-H dipole, and the space group symmetry. The S-wave anisotropy for the orthorhombic and monoclinic topaz-OH are also quite distinct. In the hydrated sedimentary layer of subducting slabs, transformation of a mineral assemblage consisting of coesite (SiO2) and diaspore (AlOOH) to topaz-OH (Al2SiO4(OH)2) is likely to be accompanied by an increase in density, compressional velocity, and shear wave velocity. However

  17. Characteristics of infrared point sources associated with OH masers

    International Nuclear Information System (INIS)

    Mu Jimang; Esimbek, Jarken; Zhou Jianjun; Zhang Haijuan

    2010-01-01

    We collect 3249 OH maser sources from the literature published up to April 2007, and compile a new catalog of OH masers. We look for the exciting sources of these masers and their infrared properties from IRAS and MSX data, and make a statistical study. MSX sources associated with stellar 1612 MHz OH masers are located mainly above the blackbody line; this is caused by the dust absorption of stellar envelopes, especially in the MSX A band. The mid-IR sources associated with stellar OH masers are concentrated in a small region in an [A]-[D] vs. [A]-[E] diagram with a small fraction of contamination; this gives us a new criterion to search for new stellar OH masers and distinguish stellar masers from unknown types of OH masers. IR sources associated with 1612 MHz stellar OH masers show an expected result: the average flux of sources with F60 > F25 increases with increasing wavelength, while those with F60 F25.

  18. Low 25-OH vitamin D levels at time of diagnosis and recurrence of ovarian cancer.

    Science.gov (United States)

    Granato, Teresa; Manganaro, Lucia; Petri, Luca; Porpora, Maria Grazia; Viggiani, Valentina; Angeloni, Antonio; Anastasi, Emanuela

    2016-02-01

    The objective of this study was to evaluate the correlation between 25-OH vitamin D and ovarian cancer as a diagnostic marker or recurrence disease marker. We studied the following: (1) 61 women without gynecologic diseases, (2) 45 women affected by benign ovarian disease, (3) 46 women with recent diagnosis of ovarian cancer, (4) 26 follow-up women with recurrent ovarian cancer, and (5) 32 follow-up women with stable ovarian cancer. The 25-OH vitamin D was quantified with LUMIPULSE® G 25-OH vitamin D on LUMIPULSE® G 1200 (Fujirebio, Japan). As a threshold value, identified by ROC curve analysis, 20.2 ng/mL (sensitivity 73.3 %, specificity 84 %) was chosen corresponding to the limit between sufficient and insufficient 25-OH vitamin D according to the WHO. Low 25-OH vitamin D levels were observed in 26 % of women without gynecologic diseases, in 80 % of women with recent diagnosis of ovarian cancer and in 24 % women affected by benign ovarian diseases (p < 0.001). The follow-up study showed an insufficient level of 25-OH vitamin D in 73 % women with recurrent ovarian cancer and in 47 % women with stable ovarian cancer (p < 0.0003). This study showed that patients with ovarian cancer are often insufficient in 25-OH vitamin D compared to women with benign ovarian diseases. The women with recurrent ovarian cancer presented more often low levels compared to women with stable ovarian cancer. This study suggests that 25-OH vitamin D, due to its antiproliferative properties, can be a good marker for ovarian cancer also.

  19. SMA OBSERVATIONS OF THE W3(OH) COMPLEX: PHYSICAL AND CHEMICAL DIFFERENTIATION BETWEEN W3(H{sub 2}O) AND W3(OH)

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Sheng-Li [Department of Astronomy, Yunnan University, and Key Laboratory of Astroparticle Physics of Yunnan Province, Kunming, 650091 (China); Schilke, Peter; Sánchez-Monge, Álvaro [Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln (Germany); Wu, Jingwen [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Wu, Yuefang [Department of Astronomy, Peking University, Beijing, 100871 (China); Liu, Tie [Korea Astronomy and Space Science Institute 776, Daedeokdaero, Yuseong-gu, Daejeon, Korea 305-348 (Korea, Republic of); Liu, Ying, E-mail: slqin@bao.ac.cn [Department of Physics and Hebei Advanced Thin Film Laboratory, Hebei Normal University, Shijiazhuang 050024 (China)

    2015-04-10

    We report on the Submillimeter Array (SMA) observations of molecular lines at 270 GHz toward the W3(OH) and W3(H{sub 2}O) complex. Although previous observations already resolved the W3(H{sub 2}O) into two or three sub-components, the physical and chemical properties of the two sources are not well constrained. Our SMA observations clearly resolved the W3(OH) and W3(H{sub 2}O) continuum cores. Taking advantage of the line fitting tool XCLASS, we identified and modeled a rich molecular spectrum in this complex, including multiple CH{sub 3}CN and CH{sub 3}OH transitions in both cores. HDO, C{sub 2}H{sub 5}CN, O{sup 13}CS, and vibrationally excited lines of HCN, CH{sub 3}CN, and CH{sub 3}OCHO were only detected in W3(H{sub 2}O). We calculate gas temperatures and column densities for both cores. The results show that W3(H{sub 2}O) has higher gas temperatures and larger column densities than W3(OH) as previously observed, suggesting physical and chemical differences between the two cores. We compare the molecular abundances in W3(H{sub 2}O) to those in the Sgr B2(N) hot core, the Orion KL hot core, and the Orion Compact Ridge, and discuss the chemical origin of specific species. An east–west velocity gradient is seen in W3(H{sub 2}O), and the extension is consistent with the bipolar outflow orientation traced by water masers and radio jets. A north–south velocity gradient across W3(OH) is also observed. However, with current observations we cannot be assured whether the velocity gradients are caused by rotation, outflow, or radial velocity differences of the sub-components of W3(OH)

  20. OH radio lines in comets - a review

    International Nuclear Information System (INIS)

    Gerard, E.

    1987-01-01

    A review of OH cometary radioastronomy from the excitation of the molecule to the detailed analysis of the line profile is presented. It is suggested that the inversion models of Despois et al. (1981) and Schleicher (1983) may be improved by taking the production rates from recent UV data (when the inversion modulus is small) once the radio vs UV discrepancies are better understood. OH radiation transfer through the coma is considered. The unresolved total integrated flux density of the OH coma can be determined by carefully mapping the OH coma using a point source calibrator. The SYMCOMET method for improving the SNR of existing profiles (in order to achieve early detections) has the advantage of suppressing the antisymmetric part of the baseline ripples or instrumental profiles. 24 references

  1. A New Open-framework Iron Borophosphate from Ionic Liquids: KFe[BP2O8(OH

    Directory of Open Access Journals (Sweden)

    Guangmei Wang

    2011-04-01

    Full Text Available A new open-framework iron borophosphate, KFe[BP2O8(OH], has been obtained by ionothermal synthesis from KH2PO4, FeCl3∙4H2O, H3BO3 and [C4mpyr]Br (1-butyl-1-methylpyrrolidinium bromide. Single-crystal X-ray diffraction analysis shows that KFe[BP2O8(OH] (monoclinic, P21/c, a = 9.372(2 Å , b = 8.146(2Å , c = 9.587(2 Å, β = 101.18(3°, V = 718.0(2Å3 and Z = 4 has a three-dimensional (3-D framework structure composed by {Fe(IIIO5(OH} octahedra as well as {BO3(OH} and {PO4} tetrahedra. As anionic structural sub-unit, KFe[BP2O8(OH], contains an infinite open-branched {[BP2O8(OH]4-} chain which is formed by alternating {BO3(OH} and {PO4} tetrahedra. {Fe(IIIO5(OH} octahedra share common O corners with five phosphate tetrahedra and the OH corner links to the hydrogen borate group to give a 3D framework. The negative charges of the inorganic framework are balanced by K+ ions.

  2. Topologically identical, but geometrically isomeric layers in hydrous α-, β-Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})]·H{sub 2}O and anhydrous Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Na; Klepov, Vladislav V. [Forschungszentrum Jülich GmbH, Institute for Energy and Climate Research (IEK-6), 52428 Jülich (Germany); Villa, Eric M. [Department of Chemistry, Creighton University, 2500 California Plaza, Omaha NE 68178 (United States); Bosbach, Dirk [Forschungszentrum Jülich GmbH, Institute for Energy and Climate Research (IEK-6), 52428 Jülich (Germany); Suleimanov, Evgeny V. [Department of Chemistry, Lobachevsky State University of Nizhny Novgorod, 603950 Nizhny Novgorod (Russian Federation); Depmeier, Wulf [Institut für Geowissenschaften, Universität zu Kiel, 24118 Kiel (Germany); Albrecht-Schmitt, Thomas E., E-mail: albrecht-schmitt@chem.fsu.edu [Department of Chemistry and Biochemistry, Florida State University, 102 Varsity Way, Tallahassee, FL 32306-4390 (United States); Alekseev, Evgeny V., E-mail: e.alekseev@fz-juelich.de [Forschungszentrum Jülich GmbH, Institute for Energy and Climate Research (IEK-6), 52428 Jülich (Germany); Institut für Kristallographie, RWTH Aachen University, 52066 Aachen (Germany)

    2014-07-01

    The hydrothermal reaction of uranyl nitrate with rubidium nitrate and arsenic (III) oxide results in the formation of polymorphic α- and β-Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})]·H{sub 2}O (α-, β-RbUAs) and the anhydrous phase Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})] (RbUAs). These phases were structurally, chemically and spectroscopically characterized. The structures of all three compounds are based upon topologically identical, but geometrically isomeric layers. The layers are linked with each other by means of the Rb cations and hydrogen bonding. Dehydration experiments demonstrate that water deintercalation from hydrous α- and β-RbUAs yields anhydrous RbUAs via topotactic reactions. - Graphical abstract: Three different layer geometries observed in the structures of Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})] and α- and β- Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})]·H{sub 2}O. Two different coordination environments of uranium polyhedra (types I and II) are shown schematically on the top of the figure. - Highlights: • Three new uranyl arsenates were synthesized from the hydrothermal reactions. • The phases consist of the topologically identical but geometrically different layers. • Topotactic transitions were observed in the processes of mono-hyrates dehydration.

  3. Implication of protein tyrosine phosphatase 1B in MCF-7 cell proliferation and resistance to 4-OH tamoxifen

    International Nuclear Information System (INIS)

    Blanquart, Christophe; Karouri, Salah-Eddine; Issad, Tarik

    2009-01-01

    The protein tyrosine phosphatase 1B (PTP1B) and the T-cell protein tyrosine phosphatase (TC-PTP) were initially thought to be mainly anti-oncogenic. However, overexpression of PTP1B and TC-PTP has been observed in human tumors, and recent studies have demonstrated that PTP1B contributes to the appearance of breast tumors by modulating ERK pathway. In the present work, we observed that decreasing the expression of TC-PTP or PTP1B in MCF-7 cells using siRNA reduced cell proliferation without affecting cell death. This reduction in proliferation was associated with decreased ERK phosphorylation. Moreover, selection of tamoxifen-resistant MCF-7 cells, by long-term culture in presence of 4-OH tamoxifen, resulted in cells that display overexpression of PTP1B and TC-PTP, and concomitant increase in ERK and STAT3 phosphorylation. siRNA experiments showed that PTP1B, but not TC-PTP, is necessary for resistance to 4-OH tamoxifen. Therefore, our work indicates that PTP1B could be a relevant therapeutic target for treatment of tamoxifen-resistant breast cancers.

  4. Standard Glbbs Energy of Formation of the Hydroxyl Radical in Aqueous Solution. Rate Constants for the Reaction C102- -t O3 S 03- -t CIO,

    DEFF Research Database (Denmark)

    Klaning, U. K.; Sehested, Knud; Holcman, J.

    1985-01-01

    The rate constants of the following reactions were determined by pulse radiolysis and stopped-flow experiments: C102- + O3 + C102 + 03-(k f= (4 f 1) X lo6 dm3 mol-' s-', k, = (1.8 f 0.2) X lo5 dm3 mol-' s-]); C102 + OH - C103- + H+ (k = (4.0 * 0.4) X lo9 dm3 mol-' s-l); C102 + 0- - C103- (k = (2.......7 * 0.4) X lo9 dm3 mol-' s-l); and O3 + C102 - C103 + O2 (k = (1.05 f 0.10) X lo3 dm3 mol-l s-'), where kf is the forward rate of reaction and k, is the reverse rate of reaction. The standard Gibbs energy of formation of OH in aqueous solution A&O,,(OH) and the corresponding standard oxidation potential...

  5. Fabrication and properties of highly luminescent materials from Tb(OH)3-SiO2 and Tb(OH)3-SiO2:Eu3+ nanotubes

    International Nuclear Information System (INIS)

    Tran Thu Huong; Tran Kim Anh; Le Quoc Minh

    2009-01-01

    Luminescent nanomaterials with one-dimensional (1D) structures have attracted much attention due to their unique properties and potential applications in nanophotonics and nanobiophotonics. In this paper, we report a synthesis of terbium - hydroxide - at - silica Tb(OH) 3 -SiO 2 and Tb(OH) 3 -SiO 2 :Eu 3+ nanotubes. Terbium - hydroxide tubes were synthesized by soft template method. The size of the tubes can be controlled precisely and have outer diameters ranging from 80 to 120 nm, wall thickness of about 30 nm, and lengths ranging from 300 to 800 nm. To fabricate core/shell materials, the seed growth method is used. FESEM, X-ray diffraction, Raman spectra of Tb(OH) 3 and Tb(OH) 3 -SiO 2 nanotubes were investigated. The photoluminescence (PL) spectrum of Tb(OH) 3 under 325 nm excitation consists of four main peaks at 488, 542, 582, and 618 nm. Furthermore, a preliminary suggestion for the mechanism of growth of the Tb(OH) 3 nanotubes using the soft - template synthesis technique has been proposed. The PL intensity from Tb(OH) 3 -SiO 2 or Tb(OH) 3 -SiO 2 :Eu 3+ nanotubes is much stronger than that of Tb(OH) 3 .

  6. Quadrupole hyperfine structure and splitting of Δ-levels in the microwave spectra of KOH, RbOH and CsOH in the 100 GHz region

    International Nuclear Information System (INIS)

    Kuijpers, P.; Dymanus, A.; Toerring, T.

    1977-01-01

    Hyperfine structure of rotational transitions of KOH, RbOH and CsOH in various v 2 - and l-states has been carefully measured in the 100 GHz range. From the observed splittings and broadenings information about quadrupole coupling constant (eqQ) of the K nucleus in KOH and about the spacing (Esub(Δ) - Esub(Σ)) between Σ and Δ levels in the vibrational spectrum of KOH, RbOH and CsOH has been derived. The measured value of the eqQ of KOH is close to that of KF. The separation between Σ and Δ levels is found to be rather similar for the group of the alkali hydroxides increasing gradually when progressing from LiOH to CsOH. (orig.) [de

  7. Investigation of Mg(OH)2 nanoparticles as an antibacterial agent

    International Nuclear Information System (INIS)

    Dong Chunxu; Cairney, John; Sun Qunhui; Maddan, Orville Lee; He Gaohong; Deng Yulin

    2010-01-01

    Our experimental results of using Mg(OH) 2 nanoparticles as an antibacterial agent are reported in this study. The antibacterial behavior of Mg(OH) 2 nanoparticles in liquid culture and in paper sheets was investigated. The colony forming units (CFU) counting and the headspace gas chromatography (HS-GC) measurement were used to determine the cell viability. Results indicate that Mg(OH) 2 nanoparticles are effective antibacterial agent against Escherichia coli (E. coli) and Burkholderia phytofirmans, and the OH - and Mg 2+ ions in Mg(OH) 2 water suspension were found not to be the reason for killing the bacteria. Mg(OH) 2 nanoparticles could be added directly to wood pulp to make paper sheets, whose antibacterial efficiency increased with the increase of the nanoparticle amount. The possible mechanism of antibacterial effect of Mg(OH) 2 nanoparticles is discussed.

  8. Direct observation of OH production from the ozonolysis of olefins

    Science.gov (United States)

    Donahue, Neil M.; Kroll, Jesse H.; Anderson, James G.; Demerjian, Kenneth L.

    Ozone olefin reactions may be a significant source of OH in the urban atmosphere, but current evidence for OH production is indirect and contested. We report the first direct observation of OH radicals from the reaction of ozone with a series of olefins (ethene, isoprene, trans-2-butene and 2,3 dimethyl-2-butene) in 4-6 torr of nitrogen. Using LIF to directly observe the steady-state of OH produced by the initial ozone-olefin reaction and subsequently destroyed by the OH-olefin reaction, we are able to establish OH yields broadly consistent with indirect values. The identification of the OH is unequivocal, and there is no indication that it is produced by a secondary process. To support these observations, we present a complete ab-initio potential energy surface for the O3-ethene reaction, extending from the reactants to available products.

  9. Effects of optical diagnostic techniques on the accuracy of laminar flame speeds measured from Bunsen flames: OH* chemiluminescence, OH-PLIF and acetone/kerosene-PLIF

    Science.gov (United States)

    Wu, Yi; Modica, Vincent; Yu, Xilong; Li, Fei; Grisch, Frédéric

    2018-01-01

    The effects of optical diagnostic techniques on the accuracy of laminar flame speed measured from Bunsen flames were investigated. Laminar flame speed measurements were conducted for different fuel/air mixtures including CH4/air, acetone/air and kerosene (Jet A-1)/air in applying different optical diagnostic techniques, i.e. OH* chemiluminescence, OH-PLIF and acetone/kerosene-PLIF. It is found that the OH* chemiluminescence imaging technique cannot directly derive the location of the outer edge of the fresh gases and it is necessary to correct the position of the OH* peak to guarantee the accuracy of the measurements. OH-PLIF and acetone/kerosene-PLIF respectively are able to measure the disappearance of the fresh gas contour and the appearance of the reaction zone. It shows that the aromatic-PLIF technique gives similar laminar flame speed values when compared with those obtained from corrected OH* chemiluminescence images. However, discrepancies were observed between the OH-PLIF and the aromatic-PLIF techniques, in that OH-PLIF slightly underestimates laminar flame speeds by up to 5%. The difference between the flame contours obtained from different optical techniques are further analysed and illustrated with 1D flame structure simulation using detailed kinetic mechanisms.

  10. Natural Rosin-based Phosphate Diester Surfactant Assisted One-step Synthesis of 3D Flowerlikeβ-Ni(OH)2/γ-Ni(OH)2 Composite Nano-microspheres

    Institute of Scientific and Technical Information of China (English)

    BoShi Wu; Juan Li; ChunRui Han; Feng Xu

    2018-01-01

    Self-assembled uniform 3Dflowerlikeβ-Ni(OH)2/g-Ni(OH)2composite nano-microspheres with hollow interiors were successfully synthesized via a facile aqueous-ethanol mixed solvothermal method, using nickel sulfate as a precursor, urea as a precipitant, and dehydroabietic based phosphate diester sodium (DDPDS) as a surfactant. The prepared 3D flowerlikeβ-Ni(OH)2/g-Ni(OH)2composite nano-microspheres were tested as supercapacitors in a two-electrode cell with 6 mol/L KOH electrolyte. In addition, the influence of DDPDS concentration on the morphology and size of 3Dflowerlikeβ-Ni(OH)2/g-Ni(OH)2composite nano-microspheres was studied at 180℃. X-ray diffraction (XRD), scanning electron microscopy (SEM), BET(Brunauer, Emmett and Teller)techniques, and equity default swap (EDS) were used to characterize the structure, morphology, and size of the as-prepared samples. Moreover, a possible formation mechanism of the 3Dflowerlikeβ-Ni(OH)2/g-Ni(OH)2composite nano-microspheres was proposed based on the effects of DDPDS concentrationand reaction time. The surfactant micelles were used as soft templates to induce the self-assembly of nanosheets. The crystallinity of the 3D flowerlikeβ-Ni(OH)2/g-Ni(OH)2composite nano-microspheres improved with the increase of DDPDS concentration, and the morphology and size of synthetic nano-microspheres could be controlled.

  11. Heterogeneous processing of biomass burning aerosol proxies by OH radicals for a wide range of OH concentrations and detection of volatilization products

    Science.gov (United States)

    Slade, J. H.; Knopf, D. A.

    2012-12-01

    Biomass burning aerosol (BBA) constitutes the majority of primary organic aerosol found in the atmosphere, with emission rates comparable to fossil-fuel burning. BBA affects earth's radiative budget directly through absorption and scattering of radiation or indirectly by modifying cloud radiative properties, and impacts air quality. Quantifying BBA source strength and thus its effects on air quality, human health, and climate can be difficult since these organic particles can chemically transform during atmospheric transport, a process also termed aging, due to heterogeneous reactions with oxidants and radicals such as OH. In this work we investigate the reactive uptake of OH radicals by typical BBA compounds that also serve as molecular markers for source apportionment studies. Organic substrates of cellulose pyrolysis products such as levoglucosan (1,6-anhydro-β-glucopyranose, C6H10O5), resin acids such as abietic acid (1-phenanthrenecarboxylic acid, C20H30O2), and lignin decomposition products such as 5-nitroguaiacol (2-methoxy-5-nitrophenol, C7H7NO4) have been exposed to a wide range of OH concentrations (~107-1011 cm-3), in presence of O2 in a rotating wall flow reactor operated at 2-6 mbar coupled to a custom built chemical ionization mass spectrometer (CIMS). OH radicals were generated through H2 dissociation in an Evenson microwave resonant cavity operated at 2.45 GHz followed by reaction with O2 or NO2. In addition, potential volatilization of organic material due to heterogeneous oxidation by OH has been determined in-situ by monitoring the volatile organic compounds using a high resolution-proton transfer reaction-time of flight-mass spectrometer (HR-PTR-ToF-MS). The volatilization studies are conducted at 1 atm and OH is generated by O3 photolysis in the presence of H2O vapor and quantified using a photochemical box model as well as through reaction with a known concentration of isoprene (2-methyl-1,3-butadiene, C5H8). Reactive uptake validation

  12. Detection of OH radicals from IRAS sources

    International Nuclear Information System (INIS)

    Lewis, B.M.; Eder, J.; Terzian, Y.

    1985-01-01

    An efficient method for detecting new OH/infrared stars is to begin with IRAS source positions, selected for appropriate infrared colours, and using radio-line observations to confirm the OH properties. The authors demonstrate the validity of this approach here, using the Arecibo 305 m radio-telescope to confirm the 1,612 MHz line observations of sources in IRAS Circulars 8 and 9; the present observations identify 21 new OH/infrared stars. The new sources have weaker 1,612 MHz fluxes, bluer (60-25) μm colours and a smaller mean separation between the principal emission peaks than previous samples. (author)

  13. Synthesis, crystal structure refinement, and nonlinear-optical properties of CaB3O5(OH): Comparative crystal chemistry of calcium triborates

    International Nuclear Information System (INIS)

    Yamnova, N. A.; Aksenov, S. M.; Stefanovich, S. Yu.; Volkov, A. S.; Dimitrova, O. V.

    2015-01-01

    Calcium triborate CaB 3 O5(OH) obtained by hydrothermal synthesis in the Ca(OH) 2 –H 3 BO 3 –Na 2 CO 3 –KCl system is studied by single-crystal X-ray diffraction. The parameters of the orthorhombic unit cell are as follows: a = 13.490(1), b = 6.9576(3), and c = 4.3930(2) Å; V = 412.32(3) Å 3 and space group Pna2 1 . The structure is refined in the anisotropic approximation of the atomic displacement parameters to R = 4.28% using 972 vertical bar F vertical bar > 4σ(F). It is confirmed that the crystal structure of Ca triborate CaB 3 O 5 (OH) is identical to that described earlier. The hydrogen atom is localized. An SHG signal stronger than that of the quartz standard is registered. The phase transition of calcium triborate into calciborite is found on heating. The comparative crystal-chemical analysis of a series of borates with the general chemical formula 2CaO · 3B 2 O 3 · nH 2 O (n = 0–13) with the constant CaO: B 2 O 3 = 2: 3 ratio and variable content of water is performed

  14. Synthesis and structure of a 1,6-hexyldiamine heptaborate, [H3N(CH2)6NH3][B7O10(OH)3

    International Nuclear Information System (INIS)

    Yang Sihai; Li Guobao; Tian Shujian; Liao Fuhui; Xiong Ming; Lin Jianhua

    2007-01-01

    A new 1,6-hexyldiamine heptaborate, [H 3 N(CH 2 ) 6 NH 3 ][B 7 O 10 (OH) 3 ] (1), has been solvothermally synthesized and characterized by single-crystal X-ray diffraction, FTIR, elemental analysis, and thermogravimetric analysis. Compound 1 crystallizes in monoclinic system, space group P2 1 /n with a=8.042(2) A, b=20.004(4) A, c=10.103(2) A, and β=90.42(3) deg. The anionic [B 7 O 10 (OH) 3 ] n 2n- layers are interlinked via hydrogen bonding to form a 3D supramolecular network containing large channels, in which the templated [H 3 N(CH 2 ) 6 NH 3 ] 2+ cations are located. - Graphical abstract: A layered 1,6-hexyldiamine heptaborate, [H 3 N(CH 2 ) 6 NH 3 ][B 7 O 10 (OH) 3 ], was solvothermally synthesized at 150 deg. C. It is a layer borate and crystallized in monoclinic space group P2 1 /n with a=8.042(2) A, b=20.004(4) A, c=10.103(2) A, β=90.42(3) deg

  15. XPS, TEM and NRA investigations of Zn(Se,OH)/Zn(OH){sub 2} films on Cu(In,Ga)(S,Se){sub 2} substrates for highly efficient solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Eisele, W.; Ennaoui, A.; Schubert-Bischoff, P.; Giersig, M.; Pettenkofer, C.; Krauser, J.; Lux-Steiner, M. [Hahn-Meitner Inst., Berlin (Germany); Zweigart, S.; Karg, F. [Siemens and Shell Solar, Munich (Germany)

    2003-01-01

    Structural and compositional properties of Zn(Se,OH)/Zn(OH){sub 2} buffer layers deposited by chemical bath deposition(CBD) on Cu(In,Ga)(S,Se){sub 2} (CIGSS) absorbers are investigated. Due to the aqueous nature of the CBD process, oxygen and hydrogen were incorporated into the 'ZnSe' buffer layer mainly in the form of Zn(OH){sub 2} as is shown by X-ray photoelectron spectroscopy and nuclear reaction analysis (NRA) measurements leading to the nomenclature 'Zn(Se,OH)'. Prior to the deposition of Zn(Se,OH), a zinc treatment of the absorber was performed. During that treatment a layer mainly consisting of Zn(OH){sub 2} grew to a thickness of several nanometer. The whole buffer layer therefore consists of a Zn(Se,OH)/Zn(OH){sub 2} structure on CIGSS. Part of the Zn(OH){sub 2} in both layers (i.e. the Zn(Se,OH) and the Zn(OH){sub 2} layer) might be converted into ZnO during measurements or storage. Scanning electron microscopy pictures showed that a complete coverage of the absorber with the buffer layer was achieved. Transmission electron microscopy revealed the different regions of the buffer layer: An amorphous area (possibly Zn(OH){sub 2}) and a partly nanocrystalline area, where lattice planes of ZnSe could be identified. Solar cell efficiencies of ZnO/Zn(Se,OH)/Zn(OH){sub 2}/CIGSS devices exceed 14% (total area).(author)

  16. Canted antiferromagnetism in KNi3[PO3(F,OH)]2[PO2(OH)2]F2 with a stair-case Kagomé lattice

    Science.gov (United States)

    Liu, Li-Chen; Ren, Wei-Jian; Huang, Ya-Xi; Pan, Yuanming; Mi, Jin-Xiao

    2017-10-01

    A new nickel phosphate KNi3[PO3(F,OH)]2[PO2(OH)2]F2 has been synthesized using a modified hydrothermal method. Structural characterizations show that it adopts a 3D framework structure with 2D layers of Ni octahedra in a stair-case Kagomé lattice. The Ni2 octahedron at the inversion center shares two trans-faces with Ni1 octahedra to form a linear trimer (Ni3O8F6) as the basic structural unit. The Ni-trimers are linked between themselves by sharing F-corners and to [PO3(F,OH)] tetrahedral groups by sharing O-corners to form 2D stair-case Kagomé layers, which are parallel to the (100) plane and are stacked along the a-axis. Successive Kagomé layers are combined together by [PO2(OH)2] tetrahedral groups and interstice cations K+. Magnetic measurements reveal that KNi3[PO3(F,OH)]2[PO2(OH)2]F2 exhibits a canted antiferromagnetic ordering with a ferromagnetic component at low temperatures.

  17. Co-existence of long-range order and spin fluctuation in a new geometric frustration series M2(OH)3Cl

    International Nuclear Information System (INIS)

    Zheng, X.G.; Hagihala, Masato; Toriyi, Takato

    2007-01-01

    Recently, we observed the co-existence of a long-range magnetic order and spin fluctuation in a clean compound of clinoatacamite, Cu 2 (OH) 3 Cl (PRL95 (2005) 057201). The present work reports magnetic studies on other compounds of this transition metal series M 2 (OH) 3 Cl, where M represents three-dimensional (3D)-electron magnetic ions of Co 2+ , Fe 2+ , etc., respectively. The present study shows that this co-existence is a common feature of the M 2 Cl(OH) 3 series, no matter whether it is anti-ferromagnetic, as in the case of Fe 2 (OH) 3 Cl (T N =15 K), or ferromagnetic, as in the case of Co 2 (OH) 3 Cl (T C =10.5 K). These compounds show a 3D network of corner-sharing tetrahedrons for the magnetic ions. The tetrahedron is slightly tilted with roughly 10% longer distance between the M-M bonded by Cl than those bonded by O and this distortion is suspected to be responsible for the partial order. This research suggests that the transition metal hydroxyhalide M 2 Cl(OH) 3 series are new geometric frustration system on tetrahedral lattice for d-electron spins

  18. Electrocatalytic Activity for CO, MeOH, and EtOH Oxidation on the Surface of Pt-Ru Nanoparticles Supported by Metal Oxide

    Directory of Open Access Journals (Sweden)

    Kwang-Sik Sim

    2011-01-01

    Full Text Available This paper describes the electrocatalytic activity for CO, MeOH, and EtOH oxidation on the surface of Pt-Ru nanoparticles supported by metal oxide (Nb-TiO2-H prepared for use in a fuel cell. To prepare Nb-TiO2-supported Pt-Ru nanoparticles, first, the Nb-TiO2 supports were prepared by sol-gel reaction of titanium tetraisopropoxide with a small amount of the niobium ethoxide in polystyrene (PS colloids. Second, Pt-Ru nanoparticles were then deposited by chemical reduction of the Pt4+ and Ru3+ ions onto Nb-TiO2 supports (Pt-Ru@Nb-TiO2-CS. Nb element was used to reduce electrical resistance to facilitate electron transport during the electrochemical reactions on a fuel cell electrode. Finally, the Pt-Ru@Nb-TiO2-H catalysts were formed by the removal of core-polystyrene ball from Pt-Ru@TiO2-CS at 500∘C. The successfully prepared Pt-Ru electrocatalysts were confirmed via TEM, XPS, and ICP analysis. The electrocatalytic efficiency of Pt-Ru nanoparticles was evaluated via CO, MeOH, and EtOH oxidation for use in a direct methanol fuel cell (DMFC. As a result, the Pt-Ru@Nb-TiO2-H electrodes showed high electrocatalytic activity for the electrooxidation of CO, MeOH, and EtOH.

  19. Determining rotational temperatures from the OH(8-3 band, and a comparison with OH(6-2 rotational temperatures at Davis, Antarctica

    Directory of Open Access Journals (Sweden)

    F. Phillips

    2004-04-01

    Full Text Available Rotational temperatures derived from the OH(8–3 band may vary by ~18K depending on the choice of transition probabilities. This is of concern when absolute temperatures or trends determined in combination with measurements of other hydroxyl bands are important. In this paper, measurements of the OH(8–3 temperature-insensitive Q/P and R/P line intensity ratios are used to select the most appropriate transition probabilities for use with this band. Aurora, airglow and solar and telluric absorption in the OH(8–3 band are also investigated. Water vapour absorption of P1(4, airglow or auroral contamination of P1(2 and solar absorption in the vicinity of P1(5 are concerns to be considered when deriving rotational temperatures from this band.

    A comparison is made of temperatures derived from OH(6–2 and OH(8–3 spectra collected alternately at Davis (69° S, 78° E in 1990. An average difference of ~4K is found, with OH(8–3 temperatures being warmer, but a difference of this magnitude is within the two sigma uncertainty limit of the measurements.

    Key words. Atmospheric composition and structure airglow and aurora; pressure, density, and temperature

  20. H2XP:OH2 Complexes: Hydrogen vs. Pnicogen Bonds

    Directory of Open Access Journals (Sweden)

    Ibon Alkorta

    2016-02-01

    Full Text Available A search of the Cambridge Structural Database (CSD was carried out for phosphine-water and arsine-water complexes in which water is either the proton donor in hydrogen-bonded complexes, or the electron-pair donor in pnicogen-bonded complexes. The range of experimental P-O distances in the phosphine complexes is consistent with the results of ab initio MP2/aug’-cc-pVTZ calculations carried out on complexes H2XP:OH2, for X = NC, F, Cl, CN, OH, CCH, H, and CH3. Only hydrogen-bonded complexes are found on the H2(CH3P:HOH and H3P:HOH potential surfaces, while only pnicogen-bonded complexes exist on H2(NCP:OH2, H2FP:OH2, H2(CNP:OH2, and H2(OHP:OH2 surfaces. Both hydrogen-bonded and pnicogen-bonded complexes are found on the H2ClP:OH2 and H2(CCHP:OH2 surfaces, with the pnicogen-bonded complexes more stable than the corresponding hydrogen-bonded complexes. The more electronegative substituents prefer to form pnicogen-bonded complexes, while the more electropositive substituents form hydrogen-bonded complexes. The H2XP:OH2 complexes are characterized in terms of their structures, binding energies, charge-transfer energies, and spin-spin coupling constants 2hJ(O-P, 1hJ(H-P, and 1J(O-H across hydrogen bonds, and 1pJ(P-O across pnicogen bonds.

  1. Green thermal-assisted synthesis and characterization of novel cellulose-Mg(OH)2 nanocomposite in PEG/NaOH solvent.

    Science.gov (United States)

    Ponomarev, Nikolai; Repo, Eveliina; Srivastava, Varsha; Sillanpää, Mika

    2017-11-15

    Synthesis of nanocomposites was performed using microcrystalline cellulose (MCC), MgCl 2 in PEG/NaOH solvent by a thermal-assisted method at different temperatures by varying time and the amount of MCC. Results of XRD, FTIR, and EDS mapping showed that the materials consisted of only cellulose (CL) and magnesium hydroxide (MH). According to FTIR and XRD, it was found that crystallinity of MH in cellulose nanocomposites is increased with temperature and heating time and decreased with increasing of cellulose amount. The PEG/NaOH solvent has a significant effect on cellulose and Mg(OH) 2 morphology. BET and BJH results demonstrated the effects of temperature and cellulose amount on the pore size corresponding to mesoporous materials. TG and DTG analyses showed the increased thermal stability of cellulose nanocomposites with increasing temperature. TEM and SEM analyses showed an even distribution of MH nanostructures with various morphology in the cellulose matrix. The cellulose presented as the polymer matrix in the nanocomposites. It was supposed the possible interaction between cellulose and Mg(OH) 2 . The novel synthesis method used in this study is feasible, cost-efficient and environmentally friendly. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Do vibrationally excited OH molecules affect middle and upper atmospheric chemistry?

    Directory of Open Access Journals (Sweden)

    T. von Clarmann

    2010-10-01

    Full Text Available Except for a few reactions involving electronically excited molecular or atomic oxygen or nitrogen, atmospheric chemistry modelling usually assumes that the temperature dependence of reaction rates is characterized by Arrhenius' law involving kinetic temperatures. It is known, however, that in the upper atmosphere the vibrational temperatures may exceed the kinetic temperatures by several hundreds of Kelvins. This excess energy has an impact on the reaction rates. We have used upper atmospheric OH populations and reaction rate coefficients for OH(v=0...9+O3 and OH(v=0...9+O to estimate the effective (i.e. population weighted reaction rates for various atmospheric conditions. We have found that the effective rate coefficient for OH(v=0...9+O3 can be larger by a factor of up to 1470 than that involving OH in its vibrational ground state only. At altitudes where vibrationally excited states of OH are highly populated, the OH reaction is a minor sink of Ox and O3 compared to other reactions involving, e.g., atomic oxygen. Thus the impact of vibrationally excited OH on the ozone or Ox sink remains small. Among quiescent atmospheres under investigation, the largest while still small (less than 0.1% effect was found for the polar winter upper stratosphere and mesosphere. The contribution of the reaction of vibrationally excited OH with ozone to the OH sink is largest in the upper polar winter stratosphere (up to 4%, while its effect on the HO2 source is larger in the lower thermosphere (up to 1.5% for polar winter and 2.5% for midlatitude night conditions. For OH(v=0...9+O the effective rate coefficients are lower by up to 11% than those involving OH in its vibrational ground state. The effects on the odd oxygen sink are negative and can reach −3% (midlatitudinal nighttime lowermost thermosphere, i.e. neglecting vibrational excitation overestimates the odd

  3. Investigating causality in the association between 25(OH)D and schizophrenia.

    Science.gov (United States)

    Taylor, Amy E; Burgess, Stephen; Ware, Jennifer J; Gage, Suzanne H; Richards, J Brent; Davey Smith, George; Munafò, Marcus R

    2016-05-24

    Vitamin D deficiency is associated with increased risk of schizophrenia. However, it is not known whether this association is causal or what the direction of causality is. We performed two sample bidirectional Mendelian randomization analysis using single nucleotide polymorphisms (SNPs) robustly associated with serum 25(OH)D to investigate the causal effect of 25(OH)D on risk of schizophrenia, and SNPs robustly associated with schizophrenia to investigate the causal effect of schizophrenia on 25(OH)D. We used summary data from genome-wide association studies and meta-analyses of schizophrenia and 25(OH)D to obtain betas and standard errors for the SNP-exposure and SNP-outcome associations. These were combined using inverse variance weighted fixed effects meta-analyses. In 34,241 schizophrenia cases and 45,604 controls, there was no clear evidence for a causal effect of 25(OH)D on schizophrenia risk. The odds ratio for schizophrenia per 10% increase in 25(OH)D conferred by the four 25(OH)D increasing SNPs was 0.992 (95% CI: 0.969 to 1.015). In up to 16,125 individuals with measured serum 25(OH)D, there was no clear evidence that genetic risk for schizophrenia causally lowers serum 25(OH)D. These findings suggest that associations between schizophrenia and serum 25(OH)D may not be causal. Therefore, vitamin D supplementation may not prevent schizophrenia.

  4. Assessing the association between 25-OH vitamin D levels and ROMA score in a population of obese women.

    Science.gov (United States)

    Anastasi, E; Capoccia, D; Granato, T; Viggiani, V; Tartaglione, S; Manganaro, L; Angeloni, A; Leonetti, F

    2016-01-01

    The “Risk of Malignancy Algorithm” (ROMA) combines the diagnostic power of the CA125 and HE4 markers with menopausal status to predict the risk for developing epithelial ovarian cancer (EOC). The aim of this study was to evaluate the association between 25-OH vitamin D levels and ROMA score in obese women. One hundred and eighteen patients with a Body Mass Index (BMI) > 30 kg/m2 (Group 1) and 80 women with a BMI less than 25 kg / m² (Group 2) were studied. The 25-OH vitamin D was quantified with LUMIPULSE® G 1200. As a threshold value, identified by ROC curve analysis, 20.2 ng/ mL (sensitivity 73.3%, specificity 84%) was chosen corresponding to the limit between sufficient and insufficient 25-OH vitamin D according to the World Health Organization (WHO). Low 25-OH vitamin D levels were observed in 64% of obese women and in 11% of normal-weight women (p less than 0.001). ROMA score above 13% was detected only in obese women (19%). An association between low levels of 25-OH vitamin D and ROMA score was observed. Indeed, 64% of obese women with ROMA score >13% had concomitant insufficient levels of 25-OH vitamin D, while only 36% of obese women with ROMA score >13% had sufficient 25-OH vitamin D levels (p less than 0.0001). This study suggests that the deficiency of 25- OH vitamin D in obese women has a possible correlation with high ROMA score.

  5. Kinetics of the Reaction of CH3O2 Radicals with OH Studied over the 292-526 K Temperature Range.

    Science.gov (United States)

    Yan, Chao; Kocevska, Stefani; Krasnoperov, Lev N

    2016-08-11

    Reaction of methyl peroxy radicals with hydroxyl radicals, CH3O2 + OH → CH3O + HO2 (1a) and CH3O2 + OH → CH2OO + H2O (1b) was studied using pulsed laser photolysis coupled to transient UV-vis absorption spectroscopy over the 292-526 K temperature range and pressure 1 bar (bath gas He). Hydroxyl radicals were generated in the reaction of electronically excited oxygen atoms O((1)D), produced in the photolysis of N2O at 193.3 nm, with H2O. Methyl peroxy radicals were generated in the reaction of methyl radicals, CH3, produced in the photolysis of acetone at 193.3 nm, and subsequent reaction of CH3 with O2. Temporal profiles of OH were monitored via transient absorption of light from a DC discharge H2O/Ar low-pressure resonance lamp at ca. 308 nm. The absolute intensity of the photolysis light was determined by accurate in situ actinometry based on the ozone formation in the presence of molecular oxygen. The overall rate constant of the reaction is k1a+1b = (8.4 ± 1.7) × 10(-11)(T/298 K)(-0.81) cm(3) molecule(-1) s(-1) (292-526 K). The branching ratio of channel 1b at 298 K is less than 5%.

  6. Certification of OHS management in a Nordic context

    DEFF Research Database (Denmark)

    Hendriksen, Kåre; Jørgensen, Kirsten; Jørgensen, Ulrik

    2009-01-01

    ’s management to decide which elements of OHS performance they commit to while the only explicit OHS demand is to comply with legal requirements. Additionally the certification is covered by the accreditation standard requirements of confidentiality, where as the validity of a certificate end up being hidden...... for the involved stakeholders. The consequences of these foundational elements of the existing management standard are analysed and exemplified. The Nordic Minister Council has funded the project, OHS Certification as Control Instrument and Control Strategy, which together with earlier studies of the working...

  7. Mid-Infrared Properties of OH Megamaser Host Galaxies. I. Spitzer IRS Low- and High-Resolution Spectroscopy

    Science.gov (United States)

    Willett, Kyle W.; Darling, Jeremy; Spoon, Henrik W. W.; Charmandaris, Vassilis; Armus, Lee

    2011-03-01

    We present mid-infrared spectra and photometry from the Infrared Spectrograph on the Spitzer Space Telescope for 51 OH megamasers (OHMs), along with 15 galaxies confirmed to have no megamaser emission above L OH = 102.3 L sun. The majority of galaxies display moderate-to-deep 9.7 μm amorphous silicate absorption, with OHM galaxies showing stronger average absorption and steeper 20-30 μm continuum emission than non-masing galaxies. Emission from multiple polycyclic aromatic hydrocarbons (PAHs), especially at 6.2, 7.7, and 11.3 μm, is detected in almost all systems. Fine-structure atomic emission (including [Ne II], [Ne III], [S III], and [S IV]) and multiple H2 rotational transitions are observed in more than 90% of the sample. A subset of galaxies show emission from rarer atomic lines, such as [Ne V], [O IV], and [Fe II]. Fifty percent of the OHMs show absorption from water ice and hydrogenated amorphous carbon grains, while absorption features from CO2, HCN, C2H2, and crystalline silicates are also seen in several OHMs. Column densities of OH derived from 34.6 μm OH absorption are similar to those derived from 1667 MHz OH absorption in non-masing galaxies, indicating that the abundance of masing molecules is similar for both samples. This data paper presents full mid-infrared spectra for each galaxy, along with measurements of line fluxes and equivalent widths, absorption feature depths, and spectral indices.

  8. Synthesis and characterisation of Co-Co(OH)2 composite anode material on Cu current collector for energy storage devices

    Science.gov (United States)

    Yavuz, Abdulcabbar; Yakup Hacıibrahimoğlu, M.; Bedir, Metin

    2017-04-01

    A Co-Co(OH)2 modified electrode on inexpensive Cu substrate was synthesized at room temperature and demonstrated to be a promising anode material for energy storage devices. A modified Co film was obtained potentiostatically and was then potentiodynamically treated with KOH solution to form Co(OH)2. Co-Co(OH)2 coatings were obtained and were dominated by Co(OH)2 at the oxidized side, whereas Co dominant Co-Co(OH)2 occurred at the reduced side (-1.1 V). As OH- ions were able to diffuse into (out of) the film during oxidation (reduction) and did not react with the Cu current collector, the Co-Co(OH)2 electrode can be used as an anode material in energy storage devices. Although the specific capacitance of the electrodes varied depending on thickness, the redox reaction between the modified electrode and KOH electrolyte remained the same consisting of a surface-controlled and diffusion-controlled mechanism which had a desirable fast charge and discharge property. Capacity values remained constant after 250 cycles as the film evolved. Overall capacity retention was 84% for the film after 450 scans. A specific capacitance of 549 F g-1 was obtained for the Co-Co(OH)2 composite electrode in 6 M KOH at a scan rate of 5 mV s-1 and 73% of capacitance was retained when the scan rate was increased to 100 mV s-1.

  9. Investigation of OH dynamics in the argon sensitized pulse radiolysis of water vapor

    International Nuclear Information System (INIS)

    Bera, R.K.; Hanrahan, R.J.

    1986-01-01

    Reactions of OH radical were studied in systems containing 650 torr Ar and from 0.5 to 9 torr H 2 O using the method of pulse radiolysis-absorption spectroscopy. It was found that initial concentrations of OH radical increased as a function of water vapor pressure. Although loss of OH with time followed approximate second order kinetics, the raw data were fitted arbitrarily to a first order rate expression, because a second order fit requires knowledge of absolute initial OH concentrations. These can be computed from measured initial OH absorption if the extinction coefficient is known, but an accurate value was not available initially. The half-life for OH loss decreased at higher water pressures. Dependence of OH half-life on OH concentration occurs because homogeneous OH loss processes are second order in reaction intermediates, whose concentration increases with added H 2 O. A contribution by water in chaperoning OH/OH and OH/H combination is also important

  10. Effect of LiOH, NaOH and KOH on corrosion and oxide microstructure of Zr-based alloys

    International Nuclear Information System (INIS)

    Jeong, Y.H.; Kim, H.G.; Jung, Y.H.; Ruhmann, H.

    1999-01-01

    Long-term corrosion test, SIMS analysis, and TEM microstructural study were carried out to investigate the corrosion characteristics and mechanism of Zr alloys in alkali hydroxides. The corrosion tests were performed in solutions of LiOH, NaOH, KOH, RbOH, and CsOH at 350 deg. C for 500 days. SIMS analysis was performed for the specimens prepared to have an equal oxide thickness. TEM studies on the specimens with an equal oxide thickness in various solutions in both pre- and post-transition regimes were also conducted. The corrosion rate in alkali hydroxide solutions was observed to decrease as the ionic radius of alkali cation was increased. The penetration depth of cation into the oxide decreases with increasing the ionic radius of cation. Even though the oxide thickness was equal, the different oxide morphologies were observed in specimens. Namely, in LiOH solution the oxide morphology was transformed early from columnar to equiaxed structure. However, in KOH solution the columnar structure was maintained up to post-transition regime. Based on the corrosion test, SIMS analysis, and microstructural study, the cation is considered to control the corrosion in a alkali hydroxide solution and its effect is dependent on the concentration of alkali and the oxide thickness. The slight acceleration of the corrosion rate at a low concentration is thought to be caused by cation incorporation into oxide while the significant acceleration at a high concentration is due to the transformation of oxide microstructure that would be induced by cation incorporation. KOH was shown not to affect significantly the corrosion and the hydrogen pickup of Zircaloy. Therefore, it has a potential for PWR application only from the point of view of Zircaloy corrosion. (author)

  11. Electronic quenching of OH(A) by water in atmospheric pressure plasmas and its influence on the gas temperature determination by OH(A-X) emission

    NARCIS (Netherlands)

    Bruggeman, P.J.; Iza, F.; Guns, P.; Lauwers, D.; Kong, M.G.; Aranda Gonzalvo, Y.; Leys, C.; Schram, D.C.

    2010-01-01

    In this paper it is shown that electronic quenching of OH(A) by water prevents thermalization of the rotational population distribution of OH(A). This means that the observed ro-vibrational OH(A-X) emission band is (at least partially) an image of the formation process and is determined not only by

  12. Investigation of Mg(OH){sub 2} nanoparticles as an antibacterial agent

    Energy Technology Data Exchange (ETDEWEB)

    Dong Chunxu [Dalian University of Technology, State Key Laboratory of Fine Chemicals, School of Chemical Engineering (China); Cairney, John [Georgia Institute of Technology, School of Biology (United States); Sun Qunhui [Georgia Institute of Technology, Institute of Paper Science and Technology (United States); Maddan, Orville Lee [Aqua Resources Corporation (United States); He Gaohong [Dalian University of Technology, State Key Laboratory of Fine Chemicals, School of Chemical Engineering (China); Deng Yulin, E-mail: yulin.deng@chbe.gatech.ed [Georgia Institute of Technology, Institute of Paper Science and Technology (United States)

    2010-08-15

    Our experimental results of using Mg(OH){sub 2} nanoparticles as an antibacterial agent are reported in this study. The antibacterial behavior of Mg(OH){sub 2} nanoparticles in liquid culture and in paper sheets was investigated. The colony forming units (CFU) counting and the headspace gas chromatography (HS-GC) measurement were used to determine the cell viability. Results indicate that Mg(OH){sub 2} nanoparticles are effective antibacterial agent against Escherichia coli (E. coli) and Burkholderia phytofirmans, and the OH{sup -} and Mg{sup 2+} ions in Mg(OH){sub 2} water suspension were found not to be the reason for killing the bacteria. Mg(OH){sub 2} nanoparticles could be added directly to wood pulp to make paper sheets, whose antibacterial efficiency increased with the increase of the nanoparticle amount. The possible mechanism of antibacterial effect of Mg(OH){sub 2} nanoparticles is discussed.

  13. Mechanistic and kinetic studies on the OH-initiated atmospheric oxidation of fluoranthene.

    Science.gov (United States)

    Dang, Juan; Shi, Xiangli; Zhang, Qingzhu; Hu, Jingtian; Chen, Jianmin; Wang, Wenxing

    2014-08-15

    The atmospheric oxidation of polycyclic aromatic hydrocarbons (PAHs) can generate toxic derivatives which contribute to the carcinogenic potential of particulate organic matter. In this work, the mechanism of the OH-initiated atmospheric oxidation of fluoranthene (Flu) was investigated by using high-accuracy molecular orbital calculations. All of the possible oxidation pathways were discussed, and the theoretical results were compared with the available experimental observation. The rate constants of the crucial elementary reactions were evaluated by the Rice-Ramsperger-Kassel-Marcus (RRKM) theory. The main oxidation products are a range of ring-retaining and ring-opening chemicals containing fluoranthols, fluoranthones, fluoranthenequinones, nitro-fluoranthenes, dialdehydes and epoxides. The overall rate constant of the OH addition reaction is 1.72×10(-11) cm(3) molecule(-1) s(-1) at 298 K and 1 atm. The atmospheric lifetime of Flu determined by OH radicals is about 0.69 days. This work provides a comprehensive investigation of the OH-initiated oxidation of Flu and should help to clarify its atmospheric conversion. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Key issues of ultraviolet radiation of OH at high altitudes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yuhuai; Wan, Tian; Jiang, Jianzheng; Fan, Jing [State Key Laboratory of High Temperature Gasdynamics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190 (China)

    2014-12-09

    Ultraviolet (UV) emissions radiated by hydroxyl (OH) is one of the fundamental elements in the prediction of radiation signature of high-altitude and high-speed vehicle. In this work, the OH A{sup 2}Σ{sup +}→X{sup 2}Π ultraviolet emission band behind the bow shock is computed under the experimental condition of the second bow-shock ultraviolet flight (BSUV-2). Four related key issues are discussed, namely, the source of hydrogen element in the high-altitude atmosphere, the formation mechanism of OH species, efficient computational algorithm of trace species in rarefied flows, and accurate calculation of OH emission spectra. Firstly, by analyzing the typical atmospheric model, the vertical distributions of the number densities of different species containing hydrogen element are given. According to the different dominating species containing hydrogen element, the atmosphere is divided into three zones, and the formation mechanism of OH species is analyzed in the different zones. The direct simulation Monte Carlo (DSMC) method and the Navier-Stokes equations are employed to compute the number densities of the different OH electronically and vibrationally excited states. Different to the previous work, the trace species separation (TSS) algorithm is applied twice in order to accurately calculate the densities of OH species and its excited states. Using a non-equilibrium radiation model, the OH ultraviolet emission spectra and intensity at different altitudes are computed, and good agreement is obtained with the flight measured data.

  15. OH stretching frequencies in systems with intramolecular hydrogen bonds

    DEFF Research Database (Denmark)

    Spanget-Larsen, Jens; Hansen, Bjarke Knud Vilster; Hansen, Poul Erik

    2011-01-01

    OH stretching wavenumbers were investigated for 30 species with intramolecularly hydrogen bonded hydroxyl groups, covering the range from 3600 to ca. 1900 cm-1. Theoretical wavenumbers were predicted with B3LYP/6-31G(d) density functional theory using the standard harmonic approximation, as well...

  16. H+-type and OH- -type biological protonic semiconductors and complementary devices.

    Science.gov (United States)

    Deng, Yingxin; Josberger, Erik; Jin, Jungho; Roudsari, Anita Fadavi; Rousdari, Anita Fadavi; Helms, Brett A; Zhong, Chao; Anantram, M P; Rolandi, Marco

    2013-10-03

    Proton conduction is essential in biological systems. Oxidative phosphorylation in mitochondria, proton pumping in bacteriorhodopsin, and uncoupling membrane potentials by the antibiotic Gramicidin are examples. In these systems, H(+) hop along chains of hydrogen bonds between water molecules and hydrophilic residues - proton wires. These wires also support the transport of OH(-) as proton holes. Discriminating between H(+) and OH(-) transport has been elusive. Here, H(+) and OH(-) transport is achieved in polysaccharide- based proton wires and devices. A H(+)- OH(-) junction with rectifying behaviour and H(+)-type and OH(-)-type complementary field effect transistors are demonstrated. We describe these devices with a model that relates H(+) and OH(-) to electron and hole transport in semiconductors. In turn, the model developed for these devices may provide additional insights into proton conduction in biological systems.

  17. Determination of the hydrogen positions in the novel barium boroarsenate Ba[B{sub 2}As{sub 2}O{sub 8}(OH){sub 2}] by combined single crystal X-ray and powder neutron investigations

    Energy Technology Data Exchange (ETDEWEB)

    Lieb, Alexandra [School of Chemistry, University of Southampton (United Kingdom); Fakultaet fuer Verfahrens- und Systemtechnik, Lehrstuhl fuer Technische Chemie, Otto-von-Guericke-Universitaet, Magdeburg (Germany); Weller, Mark T. [School of Chemistry, University of Southampton (United Kingdom); Department of Chemistry, University of Bath (United Kingdom)

    2017-11-17

    The boroarsenate Ba[B{sub 2}As{sub 2}O{sub 8}(OH){sub 2}] was obtained by the reaction of NH{sub 4}H{sub 2}AsO{sub 4}, B(OH){sub 3} and BaBr{sub 2}.2H{sub 2}O in the melt. Ba[B{sub 2}As{sub 2}O{sub 8}(OH){sub 2}] was obtained as thin colorless needles, together with spherical crystals of BAsO{sub 4} as by-product, grown on a pellet of Ba[BAsO{sub 5}]. The products could be separated mechanically. For neutron scattering experiments a sample was prepared with {sup 11}B(OH){sub 3} as a starting material. The crystal structure of Ba[B{sub 2}As{sub 2}O{sub 8}(OH){sub 2}] was determined by single-crystal X-ray diffraction and exhibits a layer structure with an unprecedented layer topology. The exact positions of the hydrogen atoms were determined using combined single-crystal X-ray and powder neutron diffraction investigations. Ba[B{sub 2}As{sub 2}O{sub 8}(OH){sub 2}] was further characterized by IR spectroscopy and EDX analysis. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. 95 GHz methanol masers near DR 21 and DR 21(OH)

    International Nuclear Information System (INIS)

    Plambeck, R.L.; Menten, K.M.

    1990-01-01

    The BIMA array is used to map the 95-GHz 8(0) to 7 1A(+) transition of methanol and the 98-GHz J = 2-1 transition of CS toward the DR 21(OH) and DR 21 star-forming regions. Several strong methanol masers were found. The positions of the two brightest masers were measured with an accuracy of about + or - 0.3 arcsec. Toward DR 21(OH), the positions, velocities, and line shapes of the 95 GHz masers are in excellent agreement with those of the 84-GHz 5(-1) to 4 () methanol masers previously mapped by Batrla and Menten (1988), demonstrating that maser emission in both transitions originates from the same clumps of gas. The methanol masers are offset from CS emission peaks and from other known infrared and maser sources; they may possibly be clustered along the interface between outflows, traced by shock-excited H2 emission, and dense ambient gas, traced by CS emission. 25 refs

  19. High-temperature rate constant measurements for OH+xylenes

    KAUST Repository

    Elwardani, Ahmed Elsaid; Badra, Jihad; Farooq, Aamir

    2015-01-01

    The overall rate constants for the reactions of hydroxyl (OH) radicals with o-xylene (k 1), m-xylene (k 2), and p-xylene (k 3) were measured behind reflected shock waves over 890-1406K at pressures of 1.3-1.8atm using OH laser absorption near 306

  20. Topotactic transition of α-Co(OH)2 to β-Co(OH)2 anchored on CoO nanoparticles during electrochemical water oxidation: synergistic electrocatalytic effects.

    Science.gov (United States)

    Kundu, Sumana; Malik, Bibhudatta; Prabhakaran, Amrutha; Pattanayak, Deepak K; Pillai, Vijayamohanan K

    2017-08-29

    Herein, we report a single step, anionic surfactant-assisted, low temperature-hydrothermal synthetic strategy of CoO nanoparticles anchored on β-Co(OH) 2 nanosheets which show a low overpotential (295 mV @ 10 mA cm -2 ) for the oxygen evolution reaction (OER). They also demonstrate much better kinetic parameters compared to the state-of-the-art RuO 2 . Interestingly, under the OER operational conditions (in alkaline medium), the topotactic transformation of α-Co(OH) 2 to a stable Brucite-like β-Co(OH) 2 phase leads to a synergistic interaction between the β-Co(OH) 2 sheets on the CoO nanoparticles for enhancing the OER electrocatalytic activity.

  1. Harvard ER-2 OH laser-induced fluorescence instrument

    Science.gov (United States)

    Wennberg, Paul O.; Anderson, James G.

    1994-01-01

    The Harvard ER-2 OH instrument is scheduled to be integrated into the NASA ER-2 high altitude aircraft ozone payload in August 1992. Design and fabrication is presently underway. This experiment is a descendant of a balloon borne instrument designed and built in the mid-1980s. The ER-2 instrument is being designed to measure OH and HO2 as part of the NASA ozone payload for the investigation of processes controlling the concentration of stratospheric ozone. Although not specifically designed to do so, it is hoped that valid measurements of OH and HO2 can be made in the remote free troposphere with this instrument.

  2. Theoretical study of the oxidation mechanisms of naphthalene initiated by hydroxyl radicals: the OH-addition pathway.

    Science.gov (United States)

    Shiroudi, Abolfazl; Deleuze, Michael S; Canneaux, Sébastien

    2014-07-03

    The oxidation mechanisms of naphthalene by OH radicals under inert (He) conditions have been studied using density functional theory along with various exchange-correlation functionals. Comparison has been made with benchmark CBS-QB3 theoretical results. Kinetic rate constants were correspondingly estimated by means of transition state theory and statistical Rice-Ramsperger-Kassel-Marcus (RRKM) theory. Comparison with experiment confirms that, on the OH-addition reaction pathway leading to 1-naphthol, the first bimolecular reaction step has an effective negative activation energy around -1.5 kcal mol(-1), whereas this step is characterized by an activation energy around 1 kcal mol(-1) on the OH-addition reaction pathway leading to 2-naphthol. Effective rate constants have been calculated according to a steady state analysis upon a two-step model reaction mechanism. In line with experiment, the correspondingly obtained branching ratios indicate that, at temperatures lower than 410 K, the most abundant product resulting from the oxidation of naphthalene by OH radicals must be 1-naphthol. The regioselectivity of the OH(•)-addition onto naphthalene decreases with increasing temperatures and decreasing pressures. Because of slightly positive or even negative activation energies, the RRKM calculations demonstrate that the transition state approximation breaks down at ambient pressure (1 bar) for the first bimolecular reaction steps. Overwhelmingly high pressures, larger than 10(5) bar, would be required for restoring to some extent (within ∼5% accuracy) the validity of this approximation for all the reaction channels that are involved in the OH-addition pathway. Analysis of the computed structures, bond orders, and free energy profiles demonstrate that all reaction steps involved in the oxidation of naphthalene by OH radicals satisfy Leffler-Hammond's principle. Nucleus independent chemical shift indices and natural bond orbital analysis also show that the computed

  3. Experimental study of the reactions of limonene with OH and OD radicals: kinetics and products.

    Science.gov (United States)

    Braure, Tristan; Bedjanian, Yuri; Romanias, Manolis N; Morin, Julien; Riffault, Véronique; Tomas, Alexandre; Coddeville, Patrice

    2014-10-09

    The kinetics of the reactions of limonene with OH and OD radicals has been studied using a low-pressure flow tube reactor coupled with a quadrupole mass spectrometer: OH + C10H16 → products (1), OD + C10H16 → products (2). The rate constants of the title reactions were determined using four different approaches: either monitoring the kinetics of OH (OD) radicals or limonene consumption in excess of limonene or of the radicals, respectively (absolute method), and by the relative rate method using either the reaction OH (OD) + Br2 or OH (OD) + DMDS (dimethyl disulfide) as the reference one and following HOBr (DOBr) formation or DMDS and limonene consumption, respectively. As a result of the absolute and relative measurements, the overall rate coefficients, k1 = (3.0 ± 0.5) × 10(-11) exp((515 ± 50)/T) and k2 = (2.5 ± 0.6) × 10(-11) exp((575 ± 60)/T) cm(3) molecule(-1) s(-1), were determined at a pressure of 1 Torr of helium over the temperature ranges 220-360 and 233-353 K, respectively. k1 was found to be pressure independent over the range 0.5-5 Torr. There are two possible pathways for the reaction between OH (OD) and limonene: addition of the radical to one of the limonene double bonds (reactions 1a and 2a ) and abstraction of a hydrogen atom (reactions 1b and 2b ), resulting in the formation of H2O (HOD). Measurements of the HOD yield as a function of temperature led to the following branching ratio of the H atom abstraction channel: k2b/k2 = (0.07 ± 0.03) × exp((460 ± 140)/T) for T = (253-355) K.

  4. The molecular structure of the borate mineral inderite Mg(H4B3O7)(OH) · 5H2O--a vibrational spectroscopic study.

    Science.gov (United States)

    Frost, Ray L; López, Andrés; Xi, Yunfei; Lima, Rosa Malena Fernandes; Scholz, Ricardo; Granja, Amanda

    2013-12-01

    We have undertaken a study of the mineral inderite Mg(H4B3O7)(OH) · 5H2O a hydrated hydroxy borate mineral of magnesium using scanning electron microscopy, thermogravimetry and vibrational spectroscopic techniques. The structure consists of [Formula: see text] soroborate groups and Mg(OH)2(H2O)4 octahedra interconnected into discrete molecules by the sharing of two OH groups. Thermogravimetry shows a mass loss of 47.2% at 137.5 °C, proving the mineral is thermally unstable. Raman bands at 954, 1047 and 1116 cm(-1) are assigned to the trigonal symmetric stretching mode. The two bands at 880 and 916 cm(-1) are attributed to the symmetric stretching mode of the tetrahedral boron. Both the Raman and infrared spectra of inderite show complexity. Raman bands are observed at 3052, 3233, 3330, 3392 attributed to water stretching vibrations and 3459 cm(-1) with sharper bands at 3459, 3530 and 3562 cm(-1) assigned to OH stretching vibrations. Vibrational spectroscopy is used to assess the molecular structure of inderite. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. 42 CFR 84.102 - Man test 6; requirements.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Man test 6; requirements. 84.102 Section 84.102 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.102 Man test 6; requirements....

  6. A discussion on the determination of atmospheric OH and its trends

    Directory of Open Access Journals (Sweden)

    P. Jöckel

    2003-01-01

    Full Text Available The oxidation efficiency of the troposphere is largely determined by the hydroxyl radical and its global distribution. Its presence limits the lifetime of most trace gases. Because of the great importance of several of these gases for climate, ozone budget and OH itself, it is of fundamental importance to acquire knowledge about atmospheric OH and possible trends in its concentrations. In the past, average concentrations of OH and trends were largely derived using industrially produced CH3CCl3 as a chemical tracer. The analyses have given valuable, but also rather uncertain results. In this paper we describe an idealized computer aided tracer experiment which has as one of its goals to derive tracer concentration weighted, global average k(OH>, where the temporal and spatial OH distribution is prescribed and k is the reaction rate coefficient of OH with a hitherto never produced (Gedanken tracer, which is injected at a number of surface sites in the atmosphere in well known amounts over a given time period. Using a three-dimensional (3-D time-dependent chemistry transport model, k(OH> can be accurately determined from the calculated 3-D tracer distribution. It is next explored how well k(OH> can be retrieved solely from tracer measurements at a limited number of surface sites. The results from this analysis are encouraging enough to actually think about the feasibility to carry out a global dedicated tracer experiment to derive k(OH> and its temporal trends. However, before that, we propose to test the methods that are used to derive k(OH>, so far largely using CH3CCl3, with an idealized tracer experiment, in which a global chemistry transport model is used to calculate the ``Gedanken'' tracer distribution, representing the real 3-D world, from which k(OH> is derived, using only the tracer information from a limited set of surface sites. We propose here that research groups which are, or will be, involved in global average OH studies to

  7. Observations of Orion in all four 18 cm OH Thermal Absoprtion Lines

    Science.gov (United States)

    Moore, Amber M.; Momjian, Emmanuel; Troland, Thomas; Sarma, Anuj; Greisen, Eric

    2018-01-01

    We present results obtained with Karl G. Jansky Very Large Array (VLA) D-configuration observations of the 18 cm OH absorption lines in the Orion Veil; a sheet of material 2-4 pc in front of the Trapezium stars. The goals of these observations were to (a) measure the magnetic field through the Zeeman effect using the 18 cm OH mainlines at 1665 and 1667 MHz and compare the results with those obtained with the pre upgrade VLA, (b) observe all four 18 cm OH lines (the two mainlines and the two satellite lines at 1612 and 1720 MHz) to infer physical conditions in the absorbing regions. For the first goal, we found that the more recent measurements are comparable to the earlier published results. To achieve the second goal, we plan to use the Cloudy spectral synthesis code to model physical conditions based upon observations of all four 18 cm OH lines. We also anticipate using Cloudy to assess the viability of a model previously applied to the M17 PDR in which the magnetic field of the Veil is in hydrostatic equilibrium with radiation pressure of stellar uv from the Trapezium.

  8. Total OH reactivity study from VOC photochemical oxidation in the SAPHIR chamber

    Science.gov (United States)

    Yu, Z.; Tillmann, R.; Hohaus, T.; Fuchs, H.; Novelli, A.; Wegener, R.; Kaminski, M.; Schmitt, S. H.; Wahner, A.; Kiendler-Scharr, A.

    2015-12-01

    It is well known that hydroxyl radicals (OH) act as a dominant reactive species in the degradation of VOCs in the atmosphere. In recent field studies, directly measured total OH reactivity often showed poor agreement with OH reactivity calculated from VOC measurements (e.g. Nölscher et al., 2013; Lu et al., 2012a). This "missing OH reactivity" is attributed to unaccounted biogenic VOC emissions and/or oxidation products. The comparison of total OH reactivity being directly measured and calculated from single component measurements of VOCs and their oxidation products gives us a further understanding on the source of unmeasured reactive species in the atmosphere. This allows also the determination of the magnitude of the contribution of primary VOC emissions and their oxidation products to the missing OH reactivity. A series of experiments was carried out in the atmosphere simulation chamber SAPHIR in Jülich, Germany, to explore in detail the photochemical degradation of VOCs (isoprene, ß-pinene, limonene, and D6-benzene) by OH. The total OH reactivity was determined from the measurement of VOCs and their oxidation products by a Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-TOF-MS) with a GC/MS/FID system, and directly measured by a laser-induced fluorescence (LIF) at the same time. The comparison between these two total OH reactivity measurements showed an increase of missing OH reactivity in the presence of oxidation products of VOCs, indicating a strong contribution to missing OH reactivity from uncharacterized oxidation products.

  9. Summertime OH reactivity from a receptor coastal site in the Mediterranean Basin

    Directory of Open Access Journals (Sweden)

    N. Zannoni

    2017-10-01

    Full Text Available Total hydroxyl radical (OH reactivity, the total loss frequency of the hydroxyl radical in ambient air, provides the total loading of OH reactants in air. We measured the total OH reactivity for the first time during summertime at a coastal receptor site located in the western Mediterranean Basin. Measurements were performed at a temporary field site located in the northern cape of Corsica (France, during summer 2013 for the project CARBOSOR (CARBOn within continental pollution plumes: SOurces and Reactivity–ChArMEx (Chemistry and Aerosols Mediterranean Experiment. Here, we compare the measured total OH reactivity with the OH reactivity calculated from the measured reactive gases. The difference between these two parameters is termed missing OH reactivity, i.e., the fraction of OH reactivity not explained by the measured compounds. The total OH reactivity at the site varied between the instrumental LoD (limit of detection  =  3 s−1 to a maximum of 17 ± 6 s−1 (35 % uncertainty and was 5 ± 4 s−1 (1σ SD – standard deviation on average. It varied with air temperature exhibiting a diurnal profile comparable to the reactivity calculated from the concentration of the biogenic volatile organic compounds measured at the site. For part of the campaign, 56 % of OH reactivity was unexplained by the measured OH reactants (missing reactivity. We suggest that oxidation products of biogenic gas precursors were among the contributors to missing OH reactivity.

  10. Photodissociation comprehensive study of OH- on alkali halides and their interaction with colour centers

    International Nuclear Information System (INIS)

    Gomes, L.

    1985-01-01

    This work shows that the OH - defect induces changes in the electronics processes of the alkali halides such as in radiation damage and optical cycles of colour centers. Two cases were considered: with the presence of an OH - ion in the (1) excited state and (2) in the ground state; 1) the comprehensive study of resonant OH - photodissociation in several hosts showed that deep traps (for electrons) can be produced from the OH - dissociation. These traps can be effective for the capture of electrons produced in the radiation damage of the lattice as well as for trapping electrons from ionized color centers. It was observed a second channel (new) for the de-excitation of the (OH - )* molecule in KI and RbI. This effect can be effective only when the lattice around the molecule holds a large enough interstitial space. This new mechanism is responsible for the strong production at LNT of F centers and OH 0 molecules at the expenses of OH - defects. Considering the complete investigation of the full cycle it was proposed a phenomenological model that would explain the observed behaviour when one covers a wide variation of lattice parameters (KCl -> RbI); 2) It was verified that the OH - ion present in the lattice induces strong changes in the de-excitation processes of electronic defects with a spread out wave function (like F centers). A change in the reorientation behaviour of excited F 2 and F + 2 centers was also verified. Two main effects should be mentioned: A) The induced de-excitation is very fast and non-radiative on F centers. B) Another type of system investigated (F 2 and F + 2 ) has shown an intense increase of the speed of reorientation of the F 2 and F + 2 excited centers. (autor) [pt

  11. Hydrogen production by sodium borohydride in NaOH aqueous solution

    Science.gov (United States)

    Wang, Q.; Zhang, L. F.; Zhao, Z. G.

    2018-01-01

    The kinetics of hydrolysis reaction of NaBH4 in NaOH aqueous solution is studied. The influence of pH of the NaOH aqueous solution on the rate of hydrogen production and the hydrogen production efficiency are studied for the hydrolysis reaction of NaBH4. The results show that the activation energy of hydrolysis reaction of NaBH4 increased with the increase of the initial pH of NaOH aqueous solution.With the increasing of the initial pH of NaOH aqueous solution, the rate of hydrogen production and hydrogen production efficiency of NaBH4 hydrolysis decrease.

  12. Effect of 24,25-dihydroxyvitamin D3 on 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] metabolism in vitamin D-deficient rats infused with 1,25-(OH)2D3

    International Nuclear Information System (INIS)

    Yamato, H.; Matsumoto, T.; Fukumoto, S.; Ikeda, K.; Ishizuka, S.; Ogata, E.

    1989-01-01

    Previous studies revealed that administration of 24,25-dihydroxyvitamin D3 [24,25-(OH)2D3] to calcium (Ca)-deficient rats causes a dose-dependent reduction in markedly elevated serum 1,25-(OH)2D3 level. Although the results suggested that the metabolism of 1,25-(OH)2D3 was accelerated by 24,25-(OH)2D3, those experiments could not define whether the enhanced metabolism of 1,25-(OH)2D3 played a role in the reduction in the serum 1,25-(OH)2D3 level. In the present study, in order to address this issue more specifically, serum 1,25-(OH)2D3 was maintained solely by exogenous administration through miniosmotic pumps of 1,25-(OH)2D3 into vitamin D-deficient rats. Thus, by measuring the serum 1,25-(OH)2D3 concentration, the effect of 24,25-(OH)2D3 on the MCR of 1,25-(OH)2D3 could be examined. Administration of 24,25-(OH)2D3 caused a dose-dependent enhancement in the MCR of 1,25-(OH)2D3, and 1 microgram/100 g rat.day 24,25-(OH)2D3, which elevated serum 24,25-(OH)2D3 to 8.6 +/- 1.3 ng/ml, significantly increased MCR and suppressed serum levels of 1,25-(OH)2D3. The effect of 24,25-(OH)2D3 on 1,25-(OH)2D3 metabolism developed with a rapid time course, and the recovery of iv injected [1 beta-3H]1,25-(OH)2D3 in blood was significantly reduced within 1 h. In addition, there was an increase in radioactivity in the water-soluble fraction of serum as well as in urine, suggesting that 1,25-(OH)2D3 is rapidly degraded to a water-soluble metabolite(s). Furthermore, the reduction in serum 1,25-(OH)2D3 was associated with a reduction in both serum and urinary Ca levels. Because the conversion of [3H]24,25-(OH)2D3 to [3H]1,24,25-(OH)2D3 or other metabolites was minimal in these rats, 24,25-(OH)2D3 appears to act without being converted into other metabolites. These results demonstrate that 24,25-(OH)2D3 rapidly stimulates the metabolism of 1,25-(OH)2D3 and reduces its serum level

  13. Treatment with 1,25(OH){sub 2}D{sub 3}induced HDAC2 expression and reduced NF-κB p65 expression in a rat model of OVA-induced asthma

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Y.; Wang, G.F.; Yang, L.; Liu, F.; Kang, J.Q.; Wang, R.L.; Gu, W.; Wang, C.Y. [Department of Gerontology Medicine, Xinhua Hospital, Shanghai Jiatong University School of Medicine, Shanghai (China)

    2015-04-28

    Recent evidence indicates that a deficiency of 1,25-dihydroxyvitamin D{sub 3} (1,25[OH]{sub 2}D{sub 3}) may influence asthma pathogenesis; however, its roles in regulating specific molecular transcription mechanisms remain unclear. We aimed to investigate the effect of 1,25(OH){sub 2}D{sub 3} on the expression and enzyme activity of histone deacetylase 2 (HDAC2) and its synergistic effects with dexamethasone (Dx) in the inhibition of inflammatory cytokine secretion in a rat asthma model. Healthy Wistar rats were randomly divided into 6 groups: control, asthma, 1,25(OH){sub 2}D{sub 3} pretreatment, 1,25(OH){sub 2}D{sub 3} treatment, Dx treatment, and Dx and 1,25(OH){sub 2}D{sub 3} treatment. Pulmonary inflammation was induced by ovalbumin (OVA) sensitization and challenge (OVA/OVA). Inflammatory cells and cytokines in the bronchoalveolar lavage (BAL) fluid and histological changes in lung tissue were examined. Nuclear factor kappa B (NF-κB) p65 and HDAC2 expression levels were assessed with Western blot analyses and quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR). Enzyme activity measurements and immunohistochemical detection of HDAC2 were also performed. Our data demonstrated that 1,25(OH){sub 2}D{sub 3} reduced the airway inflammatory response and the level of inflammatory cytokines in BAL. Although NF-κB p65 expression was attenuated in the pretreatment and treatment groups, the expression and enzyme activity of HDAC2 were increased. In addition, 1,25(OH){sub 2}D{sub 3} and Dx had synergistic effects on the suppression of total cell infusion, cytokine release, and NF-κB p65 expression, and they also increased HDAC2 expression and activity in OVA/OVA rats. Collectively, our results indicated that 1,25(OH){sub 2}D{sub 3}might be useful as a novel HDAC2 activator in the treatment of asthma.

  14. Kinetic of the gas-phase reactions of OH radicals and Cl atoms with Diethyl Ethylphosphonate and Triethyl Phosphate

    KAUST Repository

    Laversin, H.

    2015-11-30

    In this paper, the relative-rate technique has been used to obtain rate coefficients for the reaction of two organophosphorus compounds: Triethyl phosphate (TEP) and Diethyl ethylphosphonate (DEEP) with OH radicals and Cl atoms at atmospheric pressure and at different temperatures. The calculated rate constants were fitted to the Arrhenius expression over the temperature range 298 – 352 K. The following expressions (in cm3molecule-1s-1) were obtained for the reactions of OH and CL with DEEP and TEP: kOH+DEEP= (7.84±0.65)x10-14exp((1866±824)/T), kOH+TEP = (6.54±0.42)x10-14exp((1897±626)/T), kCl+DEEP = (5.27± 0.80)x10−11exp(765±140/T) and kCl+TEP = (5.23± 0.80)x10−11exp(736± 110/T). These results show that the reaction of the studied compounds with Cl atoms proceeds more rapidly than that with OH radicals. The related tropospheric lifetimes suggest that once emitted into the atmosphere, TEP and DEEP can be removed within a few hours in areas close to their emission sources. TEP and DEEP are principally removed by OH radicals. However, in coastal areas where the Cl atoms’ concentration is higher, TEP and DEEP removal by reaction with Cl atoms could be a competitive process.

  15. The use of CH3OH additive to NaOH for etching alpha particle tracks in a CR-39 plastic nuclear track detector

    International Nuclear Information System (INIS)

    Ashry, A.H.; Abdalla, A.M.; Rammah, Y.S.; Eisa, M.; Ashraf, O.

    2014-01-01

    Fast detection of alpha particles in CR-39 detectors was investigated using a new chemical etchant. 252 Cf and 241 Am sources were used for irradiating samples of CR-39 SSNTDs with fission fragments and alpha particles in air at normal temperature and pressure. A series of experimental chemical etching are carried out using new etching solution (8 ml of 10N NaOH+1 ml CH 3 OH) at 60 °C to detect alpha particle in short time in CR-39 detectors. Suitable analyzing software has been used to analyze experimental data. From fission and alpha track diameters, the value of bulk etching rate is equal to 2.73 μm/h. Both the sensitivity and etching efficiency were found to vary with the amount of methanol in the etching solution. Pure NaOH was used as a control to compare with the result from etching in NaOH with different concentrations of CH 3 OH. The etching efficiency is determined and compared with conventional aqueous solution of 6.25N NaOH at 70 °C for etching time equals 5 h. In this study, the obtained etching efficiency shows a considerable agreement with the previous work. - Highlights: • The value of bulk etching rate is equal to 2.73 μm/h. • Fast detection of alpha particles in CR-39 detectors. • Samples of CR-39 have been irradiated with fission fragments. • Etching efficiency was determined

  16. Self-Assembled Hollow Spheres of β-Ni(OH) 2 and Their Derived Nanomaterials

    KAUST Repository

    Zhang, Shengmao

    2009-03-10

    This paper describes a novel solution-based chemical process to architect hollow spheres of β-Ni(OH) 2 with controllable sizes in submicrometer and micrometer regimes. In the synthesis, starting nickel salt (nitrate) is first converted to 6-coordinated nickel ion complex [Ni(EDA) 3] 2+ (bidentate ligand EDA = C 2H 4(NH 2) 2) to avoid rapid solid formation. Hollow and core - shell β-Ni(OH) 2 spheres can be obtained with this template-free approach under one-pot conditions. The β-Ni(OH) 2 spheres are constructed from petal-like nanobuilding units which in turn are formed from even smaller nanocrystallites. The obtained porous β-Ni(OH) 2 spheres have a large specific surface area and show a unimodal pore-size distribution. Several preparative parameters have been examined and optimized. In particular, the concentration of divalent nickel in the starting solutions plays an important role in controlling thickness of the petal-like β-Ni(OH) 2 flakes and diameter of spheres. The β-Ni(OH) 2 flakes self-assemble into final spherical products through a donut-like structural intermediate. Furthermore, the β-Ni(OH) 2 hollow spheres can be used as solid precursors to synthesize other nanostructured derivatives. In this work, phase pure inorganic nanostructures, carbon nanotube (CNT) - inorganic nanocomposites, and inorganic - inorganic nanocom-posites (e.g., NiO, Ni, NiO/Ni, Ni/β-Ni(OH) 2, CNTs/NiO, CNTs/Ni, Ni@CNTs, Fe(OH) 3/β-Ni(OH) 2, Co(OH) 2/β-Ni(OH) 2, and Mg(OH) 2/β-Ni(OH) 2) have been prepared via solid-state thermal decomposition, gas-phase reduction, solution-based reduction, surface oxidation, chemical vapor deposition, and liquid-phase deposition. A greater picture for general synthesis of Ni-containing nanomaterials is thus obtained. © 2009 American Chemical Society.

  17. Comparison of in situ ionizing radiation effects on Raman and photoluminescence intensity of high OH, low OH silica, and fluoride core fibers

    Science.gov (United States)

    Bilodeau, T. G.; Ewing, K. J.; Nau, G. M.; Aggarwal, I. D.

    1995-06-01

    An in situ study of the effects of ionizing radiation on the strength of the Raman and photoluminescence signal of high OH, low OH, and fluoride core fibers has been performed with 514.5 nm laser excitation. The fibers were irradiated with a 60Co source at a constant dose rate of 560 rads/h. The high OH fiber displayed a much slower decay of the fiber Raman intensity than the other two fibers during irradiation. The fluoride fiber exhibited the quickest decline in Raman signal with the intensity dropping by a factor of 1000 in less than 20 min. The Raman intensity of the low OH silica fiber recovered to greater than 90% of its pre-irradiation value after a post-irradiation photoanneal with 488 nm laser light. The silica fibers displayed an increase in intensity of a broad photoluminescence feature centered at 650 nm. However the fiber photoluminescence intensity remained much weaker than the Raman intensity throughout the irradiations.

  18. Antidepressants differentially related to 1,25-(OH)(2) vitamin D(3) and 25-(OH) vitamin D(3) in late-life depression

    NARCIS (Netherlands)

    Oude Voshaar, R.C.; Derks, W.J.; Comijs, H.C.; Schoevers, R.A.; Borst, M.H. de; Marijnissen, R.M.

    2014-01-01

    A low plasma 25-OH vitamin D3 level is a universal risk factor for a wide range of diseases and has also been implicated in late-life depression. It is currently unknown whether the biologically active form of vitamin D, that is, 1,25-(OH)2 vitamin D3, is also decreased in late-life depression, or

  19. Antidepressants differentially related to 1,25-(OH)(2) vitamin D-3 and 25-(OH) vitamin D-3 in late-life depression

    NARCIS (Netherlands)

    Oude Voshaar, R C; Derks, W J; Comijs, H C; Schoevers, R A; de Borst, M H; Marijnissen, R M

    2014-01-01

    A low plasma 25-OH vitamin D-3 level is a universal risk factor for a wide range of diseases and has also been implicated in late-life depression. It is currently unknown whether the biologically active form of vitamin D, that is, 1,25-(OH)(2) vitamin D-3, is also decreased in late-life depression,

  20. On OH production in water containing atmospheric pressure plasmas

    NARCIS (Netherlands)

    Bruggeman, P.J.; Schram, D.C.

    2010-01-01

    In this paper radical production in atmospheric pressure water containing plasmas is discussed. As OH is often an important radical in these discharges the paper focuses on OH production. Besides nanosecond pulsed coronas and diffusive glow discharges, several other atmospheric pressure plasmas

  1. Mechano-hydrothermal preparation of Li-Al-OH layered double hydroxides

    Science.gov (United States)

    Zhang, Fengrong; Hou, Wanguo

    2018-05-01

    A mechano-hydrothermal (MHT) method was used to synthesize Li-Al-OH layered double hydroxides (LDHs) from LiOH·H2O, Al(OH)3 and H2O as starting materials. A two-step synthesis was conducted, that is, Al(OH)3 was milled for 1 h, followed by hydrothermal treatment with LiOH·H2O solution. Effects of the LiOH/Al(OH)3 molar ratio (RLi/Al) and hydrothermal temperature (Tht) on the crystallinity, morphology, and composition of the product were examined. The resulting LDHs were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, Fourier transform infrared, and elemental analyses. The results showed that pre-milling plays a key role in the LDH formation during subsequent hydrothermal treatment. The Li/Al molar ratio of the obtained LDHs keeps constant at 0.5, independent from theRLi/Al (0.5-5.0) in the starting materials. An increase in the Tht (20-80 °C) can enhance the crystallinity and morphology regularity of the products. The so-obtained Li-Al-OH LDHs exhibit high crystallinity and well-dispersity, which may have wider applications than the aggregate ones obtained using conventional mechanochemical and Li+-imbibition methods.

  2. Differential and integral cross sections in OH(X) + Xe collisions

    Energy Technology Data Exchange (ETDEWEB)

    Sarma, Gautam; Saha, Ashim Kumar; Meulen, J. J. ter; Parker, David H., E-mail: parker@science.ru.nl [Institute for Molecules and Materials, Radboud University Nijmegen, Heijendaalseweg 135, 6525 ED Nijmegen (Netherlands); Marinakis, Sarantos, E-mail: s.marinakis@qmul.ac.uk [School of Biological and Chemical Sciences, Queen Mary University of London, Joseph Priestley Building, Mile End Road, London E1 4NS (United Kingdom)

    2015-01-21

    Differential cross sections (DCSs) for inelastic collisions of OH(X) with Xe have been measured at a collision energy of 483 cm{sup −1}. The hydroxyl (OH) radicals were initially prepared in the X{sup 2}Π{sub 3/2} (v = 0, j = 1.5, f) level using the hexapole electric field selection method. Products were detected state-selectively by [2 + 1] resonance-enhanced multiphoton ionization of OH, combined with velocity-map imaging. Integral cross sections in OH(X) + Xe at a collision energy of 490 cm{sup −1} were also measured by laser-induced fluorescence. The results are compared with exact close-coupling quantum mechanical scattering calculations on the only available ab initio potential energy surface (PES). The agreement between experimental and theoretical results is generally very satisfactory. This highlights the ability of such measurements to test the available PES for such a benchmark open-shell system. The agreement between experiment and theory for DCSs is less satisfactory at low scattering angles, and possible reasons for this disagreement are discussed. Finally, theoretical calculations of OH(X) + He DCSs have been obtained at various collision energies and are compared with those of OH(X) + Xe. The role of the reduced mass in the DCSs and partial cross sections is also examined.

  3. Differential and integral cross sections in OH(X) + Xe collisions

    International Nuclear Information System (INIS)

    Sarma, Gautam; Saha, Ashim Kumar; Meulen, J. J. ter; Parker, David H.; Marinakis, Sarantos

    2015-01-01

    Differential cross sections (DCSs) for inelastic collisions of OH(X) with Xe have been measured at a collision energy of 483 cm −1 . The hydroxyl (OH) radicals were initially prepared in the X 2 Π 3/2 (v = 0, j = 1.5, f) level using the hexapole electric field selection method. Products were detected state-selectively by [2 + 1] resonance-enhanced multiphoton ionization of OH, combined with velocity-map imaging. Integral cross sections in OH(X) + Xe at a collision energy of 490 cm −1 were also measured by laser-induced fluorescence. The results are compared with exact close-coupling quantum mechanical scattering calculations on the only available ab initio potential energy surface (PES). The agreement between experimental and theoretical results is generally very satisfactory. This highlights the ability of such measurements to test the available PES for such a benchmark open-shell system. The agreement between experiment and theory for DCSs is less satisfactory at low scattering angles, and possible reasons for this disagreement are discussed. Finally, theoretical calculations of OH(X) + He DCSs have been obtained at various collision energies and are compared with those of OH(X) + Xe. The role of the reduced mass in the DCSs and partial cross sections is also examined

  4. Synthesis, crystal structure refinement, and nonlinear-optical properties of CaB{sub 3}O{sub 5}(OH): Comparative crystal chemistry of calcium triborates

    Energy Technology Data Exchange (ETDEWEB)

    Yamnova, N. A., E-mail: aks.crys@gmail.com; Aksenov, S. M. [Moscow State University, Faculty of Geology (Russian Federation); Stefanovich, S. Yu. [Moscow State University, Faculty of Chemistry (Russian Federation); Volkov, A. S.; Dimitrova, O. V. [Moscow State University, Faculty of Geology (Russian Federation)

    2015-09-15

    Calcium triborate CaB{sub 3}O5(OH) obtained by hydrothermal synthesis in the Ca(OH){sub 2}–H{sub 3}BO{sub 3}–Na{sub 2}CO{sub 3}–KCl system is studied by single-crystal X-ray diffraction. The parameters of the orthorhombic unit cell are as follows: a = 13.490(1), b = 6.9576(3), and c = 4.3930(2) Å; V = 412.32(3) Å{sup 3} and space group Pna2{sub 1}. The structure is refined in the anisotropic approximation of the atomic displacement parameters to R = 4.28% using 972 vertical bar F vertical bar > 4σ(F). It is confirmed that the crystal structure of Ca triborate CaB{sub 3}O{sub 5}(OH) is identical to that described earlier. The hydrogen atom is localized. An SHG signal stronger than that of the quartz standard is registered. The phase transition of calcium triborate into calciborite is found on heating. The comparative crystal-chemical analysis of a series of borates with the general chemical formula 2CaO · 3B{sub 2}O{sub 3} · nH{sub 2}O (n = 0–13) with the constant CaO: B{sub 2}O{sub 3}= 2: 3 ratio and variable content of water is performed.

  5. Environmental sciences: general. 2. Water Adsorption/Absorption by CsOH Particles

    International Nuclear Information System (INIS)

    Riggs, C.A.; Ghosh, T.K.; Tompson, R.V.; Loyalka, S.K.; Viswanath, D.S.

    2001-01-01

    Cesium hydroxide in aerosol form is likely to be a significant source of radio-cesium released during a reactor transient. Cesium hydroxide particles are hydrophilic and absorb/adsorb water rapidly. The result is a rapid growth of cesium hydroxide wetted agglomerates that can deposit on surfaces by gravitational settling. However, they can also react with iodine gas to form CsI according to Eq. (1). The rapid absorption/adsorption of water by CsOH may increase the rate of absorption of iodine by CsOH. Iodine may attach itself to adsorbed water molecules on CsOH and facilitate the reaction by bringing iodine to CsOH. Thus, the iodine removal mechanism from the pressurized water reactor containment atmosphere may change: I 2(g) + 4CsOH (s) ↔ 2CsI (s) + 2CsO (s) + 2H 2 O (l) . (1) Despite the importance of CsOH as an aerosol material released during a reactor transient, we have been unable to find any isotherm data of water on cesium hydroxide in the literature. The significant hydrophilic nature of CsOH, together with its being the strongest base currently known, present challenges to collection of water adsorption data. The objective in this research was to experimentally obtain isotherm data of water vapor on CsOH for a range of temperatures and pressures on macroscopic samples using an electro-balance. These data then may be used to predict the amount of water vapor adsorbed on CsOH at other temperatures and pressures by existing models. The adsorption apparatus using a Cahn 2000 electro-balance is shown in Fig. 1. The water adsorption/absorption data on CsOH at different relative pressures of water vapor were obtained gravimetrically. A detailed description of the experimental system is given in Hassan et al. An∼70-mg sample of CsOH.H 2 O (s) was placed onto a platinum weighing dish in the hang-down tube of the balance. The sample was regenerated by heating it at 100 deg. C under a vacuum of 3.5x10 -2 mm Hg for 24 h to remove adsorbed water and other gases

  6. UNUSUAL SHOCK-EXCITED OH MASER EMISSION IN A YOUNG PLANETARY NEBULA

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, Hai-Hua; Shen, Zhi-Qiang [Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Rd, Shanghai, 200030 (China); Walsh, Andrew J. [International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth WA 6845 (Australia); Gómez, José F. [Instituto de Astrofísica de Andalucía, CSIC, Glorieta de la Astronomía s/n, E-18008, Granada (Spain); Imai, Hiroshi [Department of Physics and Astronomy, Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065 (Japan); Green, James A. [SKA Organisation, Jodrell Bank Observatory, Lower Withington, Macclesfield, Cheshire SK11 9DL (United Kingdom); Dawson, Joanne R. [Department of Physics and Astronomy and MQ Research Centre in Astronomy, Astrophysics and Astrophotonics, Macquarie University, NSW 2109 (Australia); Ellingsen, Simon P. [School of Physical Sciences, Private Bag 37, University of Tasmania, Hobart 7001, TAS (Australia); Breen, Shari L. [Australia Telescope National Facility, CSIRO Astronomy and Space Science, P.O. Box 76, Epping, NSW 1710 (Australia); Jones, Paul A.; Cunningham, Maria R. [School of Physics, University of New South Wales, Sydney, NSW 2052 (Australia); Gibson, Steven J., E-mail: haihua.qiao@curtin.edu.au [Department of Physics and Astronomy, Western Kentucky University, 1906 College Heights Blvd, Bowling Green, KY 42101 (United States)

    2016-01-20

    We report on OH maser emission toward G336.644−0.695 (IRAS 16333−4807), which is a H{sub 2}O maser-emitting Planetary Nebula (PN). We have detected 1612, 1667, and 1720 MHz OH masers at two epochs using the Australia Telescope Compact Array, hereby confirming it as the seventh known case of an OH-maser-emitting PN. This is only the second known PN showing 1720 MHz OH masers after K 3−35 and the only evolved stellar object with 1720 MHz OH masers as the strongest transition. This PN is one of a group of very young PNe. The 1612 MHz and 1667 MHz masers are at a similar velocity to the 22 GHz H{sub 2}O masers, whereas the 1720 MHz masers show a variable spectrum, with several components spread over a higher velocity range (up to 36 km s{sup −1}). We also detect Zeeman splitting in the 1720 MHz transition at two epochs (with field strengths of ∼2 to ∼10 mG), which suggests the OH emission at 1720 MHz is formed in a magnetized environment. These 1720 MHz OH masers may trace short-lived equatorial ejections during the formation of the PN.

  7. Modelling atmospheric OH-reactivity in a boreal forest ecosystem

    DEFF Research Database (Denmark)

    Mogensen, D.; Smolander, S.; Sogachev, Andrey

    2011-01-01

    We have modelled the total atmospheric OH-reactivity in a boreal forest and investigated the individual contributions from gas phase inorganic species, isoprene, monoterpenes, and methane along with other important VOCs. Daily and seasonal variation in OH-reactivity for the year 2008 was examined...

  8. Ionothermal synthesis, crystal structure, and magnetic study of Co2PO4OH isostructural with caminite.

    Science.gov (United States)

    Wang, Guangmei; Valldor, Martin; Spielberg, Eike T; Mudring, Anja-Verena

    2014-03-17

    A new framework cobalt(II) hydroxyl phosphate, Co2PO4OH, was prepared by ionothermal synthesis using 1-butyl-4-methyl-pyridinium hexafluorophosphate as the ionic liquid. As the formation of Co2PO4F competes in the synthesis, the synthesis conditions have to be judiciously chosen to obtain well-crystallized, single phase Co2PO4OH. Single-crystal X-ray diffraction analyses reveal Co2PO4OH crystallizes with space group I41/amd (a = b = 5.2713(7) Å, c = 12.907(3) Å, V = 358.63(10) Å(3), and Z = 4). Astonishingly, it does not crystallize isotypically with Co2PO4F but rather isotypically with the hydroxyl minerals caminite Mg1.33[SO4(OH)0.66(H2O)0.33] and lipscombite Fe(2–y)PO4(OH) (0 ≤ y ≤ 2/3). Phosphate tetrahedra groups interconnect four rod-packed face-sharing ∞(1){CoO(6/2)} octahedra chains to form a three-dimensional framework structure. The compound Co2PO4OH was further characterized by powder X-ray diffraction, Fourier transform–infrared, and ultraviolet–visible spectroscopy, confirming the discussed structure. The magnetic measurement reveals that Co2PO4OH undergoes a magnetic transition and presents at low temperatures a canted antiferromagnetic spin order in the ground state.

  9. Kinetic control of intralayer cobalt coordination in layered hydroxides: Co(1-0.5x)(oct) Co(x)(tet) (OH)2 (Cl)x (H2O)n.

    Science.gov (United States)

    Neilson, James R; Schwenzer, Birgit; Seshadri, Ram; Morse, Daniel E

    2009-12-07

    We report the synthesis and characterization of new structural variants of the isotypic compound with the generic chemical formula, Co(1-0.5x)(oct) Co(x)(tet) (OH)2 (Cl)x (H2O)n, all modifications of an alpha-Co(OH)2 lattice. We show that the occupancy of tetrahedrally coordinated cobalt sites and associated chloride ligands, x, is modulated by the rate of formation of the respective layered hydroxide salts from kinetically controlled aqueous hydrolysis at an air-water interface. This new level of structural control is uniquely enabled by the slow diffusion of a hydrolytic catalyst, a simple technique. Independent structural characterizations of the compounds separately describe various attributes of the materials on different length scales, revealing details hidden by the disordered average structures. The precise control over the population of distinct octahedrally and tetrahedrally coordinated cobalt ions in the lattice provides a gentle, generic method for modulating the coordination geometry of cobalt in the material without disturbing the lattice or using additional reagents. A mechanism is proposed to reconcile the observation of the kinetic control of the structure with competing interactions during the initial stages of hydrolysis and condensation.

  10. Novel Semi-Direct OH Reactivity (kOH) Measurements by Chemical Ionization Mass Spectrometry during a Chamber Instrument Comparison Campaign and Continuous Ambient Air Sampling at a Central European GAW Station

    Science.gov (United States)

    Muller, J.; Kubistin, D.; Elste, T.; Plass-Duelmer, C.; Claude, A.; Englert, J.; Holla, R.; Fuchs, H.; Hofzumahaus, A.; Holland, F.; Novelli, A.; Tillmann, R.; Wegener, R.; Rohrer, F.; Yu, Z.; Bohn, B.; Williams, J.; Pfannerstill, E.; Edtbauer, A.; Kluepfel, T.

    2016-12-01

    Total OH reactivity (kOH) has been recognized as a useful measure to gauge the potential atmospheric oxidation capacity and a few different in-situ measurement techniques have been developed over the last 15 years. Here results are presented from a novel semi-direct method developed by the German Weather Service (DWD) utilizing a chemical ionization mass spectrometer (CIMS). Recently in April 2016, the CIMS system participated in a half-blind kOH instrument comparison campaign at the Forschungszentrum Jülich (FZJ) SAPHIR chamber. Experiments provided controlled conditions with a range of different VOC mixtures and varying NOx levels, representing environments dominated by biogenic or urban emissions. Alongside CIMS, kOH was also measured by systems using the comparative reactivity method (CRM) and the pump-probe technique with OH detection. The intercomparison revealed a good performance of CIMS at lower OH reactivities (0-15 s-1), a range for which the instrumental set up was optimized. Limitations of the CIMS system consist of an upper limit for kOH detection and the need for applying a chemical correction function as a result of instrument-internal HOx recycling. Findings and instrument parameters obtained from the FZJ SAPHIR campaign and flow tube experiments are then applied to ambient air kOH measurements at the Meteorological Observatory Hohenpeissenberg (MOHp), Germany. The CIMS instrument is used there for long-term measurements of OH, H2SO4, ROx and kOH. Here, we show ambient air kOH measurements, interpreted in conjunction with volatile organic compounds (VOC) and inorganic trace gases also measured at the GAW station Hohenpeissenberg. These observations provide a unique dataset to investigate turnover rates and seasonal cycles of reactive trace gases, i.e. sources that make up total OH reactivity in this central European, rural setting.

  11. Experimental study on 1,25(OH)2 D3 amelioration of oral lichen planus through regulating NF-κB signaling pathway.

    Science.gov (United States)

    Du, J; Li, R; Yu, F; Yang, F; Wang, J; Chen, Q; Wang, X; Zhao, B; Zhang, F

    2017-09-01

    To explore the protective function of vitamin D (VD)/vitamin D receptor (VDR) on the development of oral lichen planus (OLP) and elaborate the underling mechanism of it. H&E staining, myeloid peroxidase (MPO) assays, quantitative PCR (qPCR), Western blotting, and Elisa were used to test the human biopsies and serum. QPCR, Western blotting, Elisa, and siRNA transfection were also performed in LPS-induced keratinocytes to observe the functions of vitamin D and VDR. The lack of VDR in the diseased biopsies from OLP patients was associated with activated helper T-cell type 1 (Th1)-driven inflammatory response. Importantly, the status of serum 25-hydroxyvitamin D of OLP patients was reduced consistently. In a cultured cell model, 1,25(OH) 2 D 3 could downregulate excessive production of pro-inflammatory factors induced by lipopolysaccharide (LPS) in keratinocyte HaCat cells. Mechanistically, even though LPS-induced cytokines in keratinocytes were inhibited both by nuclear factor-κB (NF-κB) inhibitor and by activator protein 1 (AP-1) inhibitor, VDR-dependent 1,25(OH) 2 D 3 blocked the activation of phosphorylated-NF-κB p65 rather than c-Jun/c-Fos in the presence of LPS stimulation. These results suggest that 1,25(OH) 2 D 3 plays an anti-inflammatory role in OLP by mediating NF-κB signaling pathway but not AP-1 signaling pathway with a VDR-dependent manner, predicting vitamin D supplement may be a potential strategy for the OLP management. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. New investigation on THz spectra of OH and SH radicals (X∏)

    Science.gov (United States)

    Martin-Drumel, M. A.; Eliet, S.; Pirali, O.; Guinet, M.; Hindle, F.; Mouret, G.; Cuisset, A.

    2012-10-01

    Pure rotational transitions of OH and SH radicals have been recorded in the THz spectral range using cw-THz and synchrotron-based FT-FIR techniques. Line lists on these radicals have been completed in the three and two lowest vibrational states for OH and SH, respectively. Furthermore, the hyperfine structure of OH and SH has been observed for the first time using infrared IR FT-spectroscopy, and at frequencies higher than 1 THz, respectively. A combined fit has been made for each of these radicals including v = 0, 1 and 2 for OH and v = 0 and 1 for SH.

  13. Effects of CH3OH Addition on Plasma Electrolytic Oxidation of AZ31 Magnesium Alloys

    Science.gov (United States)

    He, Yongyi; Chen, Li; Yan, Zongcheng; Zhang, Yalei

    2015-09-01

    Plasma electrolytic oxidation (PEO) films on AZ31 magnesium alloys were prepared in alkaline silicate electrolytes (base electrolyte) with the addition of different volume concentrations of CH3OH, which was used to adjust the thickness of the vapor sheath. The compositions, morphologies, and thicknesses of ceramic layers formed with different CH3OH concentrations were determined via X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), and scanning electron microscopy (SEM). Corrosion behavior of the oxide films was evaluated in 3.5 wt.% NaCl solution using potentiodynamic polarization tests. PEO coatings mainly comprised Mg, MgO, and Mg2SiO4. The addition of CH3OH in base electrolytes affected the thickness, pores diameter, and Mg2SiO4 content in the films. The films formed in the electrolyte containing 12% CH3OH exhibited the highest thickness. The coatings formed in the electrolyte containing different concentrations of CH3OH exhibited similar corrosion resistance. The energy consumption of PEO markedly decreased upon the addition of CH3OH to the electrolytes. The result is helpful for energy saving in the PEO process. supported by National Natural Science Foundation of China (No. 21376088), the Project of Production, Education and Research, Guangdong Province and Ministry of Education (Nos. 2012B09100063, 2012A090300015), and Guangzhou Science and Technology Plan Projects of China (No. 2014Y2-00042)

  14. Signatures of non-adiabatic dynamics in the fine-structure state distributions of the OH(X~/A~) products in the B-band photodissociation of H2O

    International Nuclear Information System (INIS)

    Zhou, Linsen; Xie, Daiqian; Guo, Hua

    2015-01-01

    A detailed quantum mechanical characterization of the photodissociation dynamics of H 2 O at 121.6 nm is presented. The calculations were performed using a full-dimensional wave packet method on coupled potential energy surfaces of all relevant electronic states. Our state-to-state model permits a detailed analysis of the OH(X ~ /A ~ ) product fine-structure populations as a probe of the non-adiabatic dissociation dynamics. The calculated rotational state distributions of the two Λ-doublet levels of OH(X ~ , v = 0) exhibit very different characteristics. The A′ states, produced mostly via the B ~ →X ~ conical intersection pathway, have significantly higher populations than the A″ counterparts, which are primarily from the B ~ →A ~ Renner-Teller pathway. The former features a highly inverted and oscillatory rotational state distribution, while the latter has a smooth distribution with much less rotational excitation. In good agreement with experiment, the calculated total OH(X ~ ) rotational state distribution and anisotropy parameters show clear even-odd oscillations, which can be attributed to a quantum mechanical interference between waves emanating from the HOH and HHO conical intersections in the B ~ →X ~ non-adiabatic pathway. On the other hand, the experiment-theory agreement for the OH(A ~ ) fragment is also satisfactory, although some small quantitative differences suggest remaining imperfections of the ab initio based potential energy surfaces

  15. Atmospheric chemistry of CF3CH2CH2OH

    DEFF Research Database (Denmark)

    Hurley, Michael D.; Misner, Jessica A.; Ball, James C.

    2005-01-01

    Relative rate techniques were used to study the kinetics of the reactions of Cl atoms and OH radicals with CF3CH2C(O)H and CF3CH2CH2OH in 700 Torr of N-2 or air diluent at 296 2 K. The rate constants determined were k(Cl+CF3CH2C(O)H) = (1.81 +/- 0.27) x 10(-11), k(OH+CF3CH2C(O)H) = (2.57 +/- 0.44...

  16. Serum 25(OH)D and Type 2 Diabetes Association in a General Population

    DEFF Research Database (Denmark)

    Husemoen, Lise-Lotte; Thuesen, Betina H; Fenger, Mogens

    2012-01-01

    OBJECTIVEThis study aimed to examine vitamin D status as a determinant for development of type 2 diabetes and deterioration of glucose homeostasis.RESEARCH DESIGN AND METHODSA random sample of the general population of Copenhagen, Denmark, was taken as part of the Inter99 study. Included were 6......,405 men and women aged 30-65 years at baseline (1999-2001), with 4,296 participating in the follow-up examination 5 years later (2004-2006). Vitamin D was determined at baseline as serum 25-hydroxyvitamin D [25(OH)D]. Diabetes was defined based on an oral glucose tolerance test and a glycosylated...... hemoglobin (HbA(1c)) test. Secondary outcomes included continuous markers of glucose homeostasis.RESULTSThe risk of incident diabetes associated with a 10 nmol/L increase in 25(OH)D was odds ratio (OR) 0.91 (95% CI 0.84-0.97) in crude analyses. The association became statistically nonsignificant after...

  17. Low-temperature structural phase transition in synthetic libethenite Cu2PO4OH

    International Nuclear Information System (INIS)

    Belik, Alexei A.; Naumov, Pance; Kim, Jungeun; Tsuda, Shunsuke

    2011-01-01

    Low-temperature structural properties of the synthetic mineral libethenite Cu 2 PO 4 OH were investigated by single-crystal X-ray diffraction, synchrotron X-ray powder diffraction, specific heat measurements, and Raman spectroscopy. A second-order structural phase transition from the Pnnm symmetry (a=8.0553(8) A, b=8.3750(9) A, c=5.8818(6) A at 180 K) to the P2 1 /n symmetry (a=8.0545(8) A, b=8.3622(9) A, c=5.8755(6) A, β=90.0012(15) at 120 K) was found at 160 K during cooling. At 120 K, the monoclinic angle is 90.0012(15) from single crystal X-ray data vs 90.083(1) from powder X-ray diffraction data. The P2 1 /n-to-Pnnm transition may be a general feature of the adamite-type compounds, M 2 XO 4 OH. - Graphical Abstract: Fragments of experimental synchrotron X-ray powder diffraction patterns of Cu 2 PO 4 OH between 100 and 280 K. Arrows show additional reflections that appear below 160 K in the monoclinic P2 1 /n phase. Highlights: → A low-temperature phase transition was found in the mineral libethenite Cu 2 PO 4 OH. → No magnetic anomalies and weak specific heat anomalies are detected. → Phase transition is of the second order. → Libethenite may exemplify a general feature of the adamite-type compounds.

  18. Room temperature chemical synthesis of Cu(OH)2 thin films for supercapacitor application

    International Nuclear Information System (INIS)

    Gurav, K.V.; Patil, U.M.; Shin, S.W.; Agawane, G.L.; Suryawanshi, M.P.; Pawar, S.M.; Patil, P.S.; Lokhande, C.D.; Kim, J.H.

    2013-01-01

    Highlights: •Cu(OH) 2 is presented as the new supercapacitive material. •The novel room temperature method used for the synthesis of Cu(OH) 2 . •The hydrous, nanograined Cu(OH) 2 shows higher specific capacitance of 120 F/g. -- Abstract: Room temperature soft chemical synthesis route is used to grow nanograined copper hydroxide [Cu(OH) 2 ] thin films on glass and stainless steel substrates. The structural, morphological, optical and wettability properties of Cu(OH) 2 thin films are studied by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), UV–vis spectrophotometer and water contact angle measurement techniques. The results showed that, room temperature chemical synthesis route allows to form the nanograined and hydrophilic Cu(OH) 2 thin films with optical band gap energy of 3.0 eV. The electrochemical properties of Cu(OH) 2 thin films are studied in an aqueous 1 M NaOH electrolyte using cyclic voltammetry. The sample exhibited supercapacitive behavior with 120 F/g specific capacitance

  19. The OH-initiated oxidation of atmospheric peroxyacetic acid: Experimental and model studies

    Science.gov (United States)

    Wu, Huihui; Wang, Yin; Li, Huan; Huang, Liubin; Huang, Dao; Shen, Hengqing; Xing, Yanan; Chen, Zhongming

    2017-09-01

    Peroxyacetic acid (PAA, CH3C(O)OOH) plays an important role in atmospheric chemistry, serving as reactive oxidant and affecting radical recycling. However, previous studies revealed an obvious gap between modelled and observed concentrations of atmospheric PAA, which may be partly ascribed to the uncertainty in the kinetics and mechanism of OH-oxidation. In this study, we measured the rate constant of OH radical reaction with PAA (kPAA+OH) and investigated the products in order to develop a more robust atmospheric PAA chemistry. Using the relative rates technique and employing toluene and meta-xylene as reference compounds, the kPAA+OH was determined to be (9.4-11.9) × 10-12 cm3 molecule-1 s-1 at 298 K and 1 atm, which is about (2.5-3.2) times larger than that parameter used in Master Chemical Mechanism v3.3.1 (MCM v3.3.1) (3.70 × 10-12 cm3 molecule-1 s-1). Incorporation of a box model and MCM v3.3.1 with revised PAA chemistry represented a better simulation of atmospheric PAA observed during Wangdu Campaign 2014, a rural site in North China Plain. It is found that OH-oxidation is an important sink of atmospheric PAA in this rural area, accounting for ∼30% of the total loss. Moreover, the major terminal products of PAA-OH reaction were identified as formaldehyde (HCHO) and formic acid (HC(O)OH). The modelled results show that both primary and secondary chemistry play an important role in the large HCHO and HC(O)OH formation under experimental conditions. There should exist the channel of methyl H-abstraction for PAA-OH reaction, which may also provide routes to HCHO and HC(O)OH formation.

  20. Where is OH and Does It Trace the Dark Molecular Gas (DMG)?

    Science.gov (United States)

    Li, Di; Tang, Ningyu; Nguyen, Hiep; Dawson, J. R.; Heiles, Carl; Xu, Duo; Pan, Zhichen; Goldsmith, Paul F.; Gibson, Steven J.; Murray, Claire E.; Robishaw, Tim; McClure-Griffiths, N. M.; Dickey, John; Pineda, Jorge; Stanimirović, Snežana; Bronfman, L.; Troland, Thomas; PRIMO Collaboration

    2018-03-01

    Hydroxyl (OH) is expected to be abundant in diffuse interstellar molecular gas because it forms along with H2 under similar conditions and forms within a similar extinction range. We have analyzed absorption measurements of OH at 1665 MHz and 1667 MHz toward 44 extragalactic continuum sources, together with the J = 1–0 transitions of 12CO, 13CO, and C18O, and the J = 2–1 transition of 12CO. The excitation temperatures of OH were found to follow a modified lognormal distribution f({T}ex})\\propto \\tfrac{1}{\\sqrt{2π }σ }\\exp ≤ft[-\\tfrac{{[{ln}({T}ex})-{ln}(3.4{{K}})]}2}{2{σ }2}\\right], the peak of which is close to the temperature of the Galactic emission background (CMB+synchrotron). In fact, 90% of the OH has excitation temperatures within 2 K of the Galactic background at the same location, providing a plausible explanation for the apparent difficulty of mapping this abundant molecule in emission. The opacities of OH were found to be small and to peak around 0.01. For gas at intermediate extinctions (AV ∼ 0.05–2 mag), the detection rate of OH with a detection limit N(OH) ≃ 1012 cm‑2 is approximately independent of AV. We conclude that OH is abundant in the diffuse molecular gas and OH absorption is a good tracer of “dark molecular gas (DMG).” The measured fraction of DMG depends on the assumed detection threshold of the CO data set. The next generation of highly sensitive low-frequency radio telescopes, such as FAST and SKA, will make feasible the systematic inventory of diffuse molecular gas through decomposing, in velocity, the molecular (e.g., OH and CH) absorption profiles toward background continuum sources with numbers exceeding what is currently available by orders of magnitude.

  1. THEORETICAL RESEARCH ON THE MULTI-CHANNEL REACTION MECHANISM AND KINETICS OF HNCS WITH OH-

    Directory of Open Access Journals (Sweden)

    Li-Jie Hou

    Full Text Available We presented a theoretical study on the detailed reaction mechanism and kinetics of the HNCS molecule with the OH-. The barrierless minimum energy path and the most favorable entrance channel have been determined by study the thermodynamic and kinetic characters of the channel with low energy barrier. The B3LYP/6-311++G** method was employed for all the geometrical optimizations and a multi-level extrapolation method based on the G3 energies was employed for further energy refinements. In addition, the analysis of the combining interaction between hydroxide ion and HNCS was performed by natural bond orbitals (NBO analysis. The calculation results indicated that the reaction of OH- with HNCS had four channels, and the channel of H-atom in HNCS direct extraction to OH- (OH-+HNCS→IM1→TS3→IM4→P2(SCN- +H2O in singlet state was the main channel with the low potential energy and high equilibrium constant and reaction rate constant. SCN- and H2O were main products.

  2. Penurunan Kromium (Cr dalam Limbah Cair Proses Penyamakan Kulit Menggunakan Senyawa Alkali Ca(OH2, NaOH, dan NaHCO3 (Studi Kasus di Pt Trimulyo Kencana Mas Semarang

    Directory of Open Access Journals (Sweden)

    Tri Joko

    2015-12-01

    Full Text Available ABTRACT Background : One of the industrial type which use hazardous materials in its production process is leather tanning industry, by using chromium compound (Cr. Chromium is a heavy metal compound which recognized has a high poison energy. Result of analysis of sampel industrial liquid waste of leather tanning of PT Trimulyo Kencana Mas (TKM Semarang showed that total chromium concervation was 49,575 m/l. This total Chromium rate was still above the standard quality of which enabled maximal 2,0 mg/l, according to Kep51/MENLH/110/1995. Alkali compound of Ca(OH2, NaOH and NaHC03 is chemicals able to be used for the processing of industrial liquid waste of pregnant leather tanning of chromium, functioning to boost up condensation pH andprecipitated chromium so that obtained chrome in theform of hydroxide chromium (Cr(OH3. Methods : which used in this research is (quasi experimental, with experiment variable repeated or referred as one group pretest ‑ posttest design. Results : of this research showed that optimum pH for the compound of each alkali at condition of pH 8, with the efficiency dissociation of chromium was equal to 99,28 % by using alkali compound of Ca(OH2 and of NaOH, while usage of NaHC03 equal to 98,50 %. Conclusions: Alkali compound of Ca(OH2, NaOH and NaHCO3 can degrade chromium concentration (Cr in liquid waste with high efficiency, that is reaching under standard quality. The most effective Compound of Alkali, evaluated from the technical aspect for the degradation of chromium concentration in liquid waste is NaOH, because with only small dose can dissociate chromium in liquid waste with high efficiency (99,28 %, For economic reason and recommendation for application in the field is Ca(OH2. Keyword : Efficiency Ca(OH2,, hydroxide chromium, NaHCO3, NaOH, pH, Chromium Compound

  3. The adsorption features between insecticidal crystal protein and nano-Mg(OH)2.

    Science.gov (United States)

    Pan, Xiaohong; Xu, Zhangyan; Zheng, Yilin; Huang, Tengzhou; Li, Lan; Chen, Zhi; Rao, Wenhua; Chen, Saili; Hong, Xianxian; Guan, Xiong

    2017-12-01

    Nano-Mg(OH) 2 , with low biological toxicity, is an ideal nano-carrier for insecticidal protein to improve the bioactivity. In this work, the adsorption features of insecticidal protein by nano-Mg(OH) 2 have been studied. The adsorption capacity could reach as high as 136 mg g -1 , and the adsorption isotherm had been fitted with Langmuir and Freundlich models. Moreover, the adsorption kinetics followed a pseudo-first or -second order rate model, and the adsorption was spontaneous and an exothermic process. However, high temperatures are not suitable for adsorption, which implies that the temperature would be a critical factor during the adsorption process. In addition, FT-IR confirmed that the protein was adsorbed on the nano-Mg(OH) 2 , zeta potential analysis suggested that insecticidal protein was loaded onto the nano-Mg(OH) 2 not by electrostatic adsorption but maybe by intermolecular forces, and circular dichroism spectroscopy of Cry11Aa protein before and after loading with nano-Mg(OH) 2 was changed. The study applied the adsorption information between Cry11Aa and nano-Mg(OH) 2 , which would be useful in the practical application of nano-Mg(OH) 2 as a nano-carrier.

  4. Characterization of plasma-induced cell membrane permeabilization: focus on OH radical distribution

    International Nuclear Information System (INIS)

    Sasaki, Shota; Honda, Ryosuke; Hokari, Yutaro; Takashima, Keisuke; Kaneko, Toshiro; Kanzaki, Makoto

    2016-01-01

    Non-equilibrium atmospheric-pressure plasma (APP) is used medically for plasma-induced cell permeabilization. However, how plasma irradiation specifically triggers permeabilization remains unclear. In an attempt to identify the dominant factor( s ), the distribution of plasma-produced reactive species was investigated, primarily focusing on OH radicals. A stronger plasma discharge, which produced more OH radicals in the gas phase, also produced more OH radicals in the liquid phase (OH aq ), enhancing the cell membrane permeability. In addition, plasma irradiation-induced enhancement of cell membrane permeability decreased markedly with increased solution thickness (<1 mm), and the plasma-produced OH aq decayed in solution (diffusion length on the order of several hundred micrometers). Furthermore, the horizontally center-localized distribution of OH aq corresponded with the distribution of the permeabilized cells by plasma irradiation, while the overall plasma-produced oxidizing species in solution (detected by iodine-starch reaction) exhibited a doughnut-shaped horizontal distribution. These results suggest that OH aq, among the plasma-produced oxidizing species, represents the dominant factor in plasma-induced cell permeabilization. These results enhance the current understanding of the mechanism of APP as a cell-permeabilization tool. (paper)

  5. Coherent cancellation of geometric phase for the OH molecule in external fields

    Science.gov (United States)

    Bhattacharya, M.; Marin, S.; Kleinert, M.

    2014-05-01

    The OH molecule in its ground state presents a versatile platform for precision measurement and quantum information processing. These applications vitally depend on the accurate measurement of transition energies between the OH levels. Significant sources of systematic errors in these measurements are shifts based on the geometric phase arising from the magnetic and electric fields used for manipulating OH. In this article, we present these geometric phases for fields that vary harmonically in time, as in the Ramsey technique. Our calculation of the phases is exact within the description provided by our recent analytic solution of an effective Stark-Zeeman Hamiltonian for the OH ground state. This Hamiltonian has been shown to model experimental data accurately. We find that the OH geometric phases exhibit rich structure as a function of the field rotation rate. Remarkably, we find rotation rates where the geometric phase accumulated by a specific state is zero, or where the relative geometric phase between two states vanishes. We expect these findings to be of importance to precision experiments on OH involving time-varying fields. More specifically, our analysis quantitatively characterizes an important item in the error budget for precision spectroscopy of ground-state OH.

  6. Nanocomposite of hexagonal β-Ni(OH){sub 2}/multiwalled carbon nanotubes as high performance electrode for hybrid supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Chaitra, K. [Department of Nanobiosciences, Centre for Emerging Technologies, Jain Global Campus, Jain University, Jakkasandra Post, Kanakapura Taluk, Ramanagara District, Bangalore Rural 562112, Karnataka (India); Nagaraju, N. [Department of Chemistry, St. Joseph' s College P.G. Centre, 46, Langford Road, Shanthinagar, Bangalore 560027, Karnataka (India); Nagaraju, Kathyayini, E-mail: nkathyayini45@gmail.com [Department of Nanobiosciences, Centre for Emerging Technologies, Jain Global Campus, Jain University, Jakkasandra Post, Kanakapura Taluk, Ramanagara District, Bangalore Rural 562112, Karnataka (India)

    2015-08-15

    β-Ni(OH){sub 2} and its composite with multiwalled carbon nanotubes (MWCNTs) were synthesized by hydrothermal process. Their electrochemical properties such as specific capacitance, energy density, power density, coulombic efficiency and charge-discharge cycles were investigated by Cyclic voltammetry (CV), Chronopotentiometry (CP) and Electrochemical impedance spectroscopy (EIS) techniques. The materials were analyzed for their textural and structural properties by different analytical techniques such as Powder X-ray diffraction (PXRD), Brunauer-Emmett-Teller (BET) surface area, Scanning electron microscopy (SEM) and Energy dispersive X-ray spectroscopy (EDS), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and Raman spectroscopy. The diffraction peaks obtained from PXRD studies and the TEM images of the materials inferred the formation of hexagonal nanostructured β- Ni(OH){sub 2} in both pure and composite materials. The composite material exhibited better electrochemical supercapacitance performance than pure β-Ni(OH){sub 2}. Their specific capacitance values were found to be 1882 F g{sup −1} and 819 F g{sup −1} respectively at a scan rate of 2 mVs{sup −1}. The presence of MWCNTs enhanced the specific capacitance value of β-Ni(OH){sub 2} nearly by 57% at 2 mVs{sup −1}. Chronopotentiometric studies conducted at a current density of 5 A/g indicated that the composite material was stable up to 5000 charge-discharge cycles. Another interesting observation made is that the composite material exhibited 100% coulombic efficiency where as it was only 84% for β-Ni(OH){sub 2} at 5000th cycle. The composite material gave an energy density of 40 Wh/kg which was nearly 4 times that of β-Ni(OH){sub 2}. - Graphical abstract: Display Omitted - Highlights: • β-Ni(OH){sub 2} and its composite with MWCNTs were synthesized by hydrothermal process. • β-Ni(OH){sub 2} and composite exhibited Csp of 819 and 1882 F/g at 2 m

  7. 76 FR 32071 - Safety Zone; Conneaut Festival Fireworks, Conneaut Harbor, Conneaut, OH

    Science.gov (United States)

    2011-06-03

    ...-AA00 Safety Zone; Conneaut Festival Fireworks, Conneaut Harbor, Conneaut, OH AGENCY: Coast Guard, DHS... Conneaut Harbor, Conneaut, OH for the Conneaut Festival Fireworks. This zone is intended to restrict vessels from a portion of Conneaut Harbor, Conneaut, OH during the Conneaut Festival Fireworks on July 3...

  8. Reaction mechanisms of phosphate with Al(OH)3 and a sandy soil

    NARCIS (Netherlands)

    Riemsdijk, van W.H.

    1979-01-01

    Al(OH) 3 is a very effective sorbent for orthophosphate especially at low pH. At low phosphate concentration c p , phosphate is adsorbed by an exchange mechanism with singly coordinated OH(H) groups residing on the surface of the Al(OH)

  9. Investigation of the crystal structure of a basic bismuth(III) nitrate with the composition [Bi6O4(OH)(4)](0.54(1))[Bi6O5(OH)(3)](0.46(1))(NO3)(5.54(1))

    DEFF Research Database (Denmark)

    Christensen, Axel Norlund; Lebech, Bente

    2012-01-01

    A basic bismuth(III) nitrate with the composition [Bi6O4(OH)(4)](0.5)[Bi6O5(OH)(3)](0.5)(NO3)(5.5) formed in a slow crystal growth mode has an ordered crystal structure with the monoclinic space group P2(1) and lattice parameters a = 15.850(3), b = 14.986(3), c = 18.230(4) angstrom, beta = 107...... a trigonal R (3) over bar cell with a = 15.1865(1) and c = 15.8416(1) angstrom (hexagonal setting). In a Rietveld type structure model refinement with a total of 28 atom sites (4 Bi, 3 N, 15 O and 6 H), the composition of this sample is determined to be [Bi6O4(OH)(4)](0.54(1))[Bi6O5(OH)(3)](0.46(1))(NO3)(5.54(1))....

  10. Clumped isotope effects during OH and Cl oxidation of methane

    DEFF Research Database (Denmark)

    Whitehill, Andrew R.; Joelsson, Lars Magnus T.; Schmidt, Johan Albrecht

    2017-01-01

    A series of experiments were carried out to determine the clumped (13CH3D) methane kinetic isotope effects during oxidation of methane by OH and Cl radicals, the major sink reactions for atmospheric methane. Experiments were performed in a 100 L quartz photochemical reactor, in which OH was produ......A series of experiments were carried out to determine the clumped (13CH3D) methane kinetic isotope effects during oxidation of methane by OH and Cl radicals, the major sink reactions for atmospheric methane. Experiments were performed in a 100 L quartz photochemical reactor, in which OH...... effects for singly substituted species were consistent with previous experimental studies. For doubly substituted methane, 13CH3D, the observed kinetic isotope effects closely follow the product of the kinetic isotope effects for the 13C and deuterium substituted species (i.e., 13,2KIE = 13KIE × 2KIE...... reactions. In a closed system, however, this effect is overtaken by the large D/H isotope effect, which causes the residual methane to become anti-clumped relative to the initial methane. Based on these results, we demonstrate that oxidation of methane by OH, the predominant oxidant for tropospheric methane...

  11. Behaviour of OH radicals in an atmospheric-pressure streamer discharge studied by two-dimensional numerical simulation

    International Nuclear Information System (INIS)

    Komuro, Atsushi; Ono, Ryo; Oda, Tetsuji

    2013-01-01

    The production process of OH radicals in an atmospheric-pressure streamer discharge is studied. A streamer discharge model is developed to analyse the characteristics of a pulsed positive streamer discharge in point-to-plane electrodes filled with humid air at atmospheric pressure. The results indicate that the behaviour of OH radicals in and after the discharge pulse is characterized by three reaction processes: ‘OH-production’, ‘OH-cycle’ and ‘OH-recombination’. The first process of OH-production includes dissociation reactions of H 2 O with O( 1 D) and N 2 (a' 1 Σ u - ), which are the main production processes of OH in the discharge. Immediately after the OH-production process, the OH radicals are destroyed by a reaction with O( 3 P) to form O 2 and H. Then the subsequent reactions produce OH again through the reaction of H + HO 2 , which is the OH-cycle process. Finally, the OH radicals are consumed by the OH-recombination process. (paper)

  12. Detection of OH from Comet Halley in the far-infrared

    International Nuclear Information System (INIS)

    Stacey, G.J.; Lugten, J.B.; Genzel, R.

    1986-01-01

    The 2 Pi 3/2 (J = 5/2 yields 3/2 + yields - parity) transition of OH was detected in comet Halley at 119.44 microns. The upper limit to the line intensity of the - yields + parity transition is 119.23 microns. The ratio of these lines is consistent with radiative pumping of the rotational levels through absorption of near ultraviolet solar photons which excite the low lying vibrational levels of OH. The far-infrared lines probe the inner regions of the coma where OH is produced through photodissociation of a parent molecule (presumably H 2 O). Hence, these lines complement the 18 cm radio measurements which are sensitive to the outer regions of the comet coma. The OH production rate is highly model dependent but is of the order 2 to 4 times 10 to the 29th power molecules/sec

  13. 41 CFR 102-79.105 - What is the Integrated Workplace?

    Science.gov (United States)

    2010-07-01

    ... changing needs of the occupants and the organization. Integrated Workplace concepts support the objectives... Workplace? 102-79.105 Section 102-79.105 Public Contracts and Property Management Federal Property... UTILIZATION OF SPACE Assignment and Utilization of Space Integrated Workplace § 102-79.105 What is the...

  14. Quantifying the causes of differences in tropospheric OH within global models

    Science.gov (United States)

    Nicely, Julie M.; Salawitch, Ross J.; Canty, Timothy; Anderson, Daniel C.; Arnold, Steve R.; Chipperfield, Martyn P.; Emmons, Louisa K.; Flemming, Johannes; Huijnen, Vincent; Kinnison, Douglas E.; Lamarque, Jean-François; Mao, Jingqiu; Monks, Sarah A.; Steenrod, Stephen D.; Tilmes, Simone; Turquety, Solene

    2017-02-01

    The hydroxyl radical (OH) is the primary daytime oxidant in the troposphere and provides the main loss mechanism for many pollutants and greenhouse gases, including methane (CH4). Global mean tropospheric OH differs by as much as 80% among various global models, for reasons that are not well understood. We use neural networks (NNs), trained using archived output from eight chemical transport models (CTMs) that participated in the Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols and Transport Model Intercomparison Project (POLMIP), to quantify the factors responsible for differences in tropospheric OH and resulting CH4 lifetime (τCH4) between these models. Annual average τCH4, for loss by OH only, ranges from 8.0 to 11.6 years for the eight POLMIP CTMs. The factors driving these differences were quantified by inputting 3-D chemical fields from one CTM into the trained NN of another CTM. Across all CTMs, the largest mean differences in τCH4 (ΔτCH4) result from variations in chemical mechanisms (ΔτCH4 = 0.46 years), the photolysis frequency (J) of O3 → O(1D) (0.31 years), local O3 (0.30 years), and CO (0.23 years). The ΔτCH4 due to CTM differences in NOx (NO + NO2) is relatively low (0.17 years), although large regional variation in OH between the CTMs is attributed to NOx. Differences in isoprene and J(NO2) have negligible overall effect on globally averaged tropospheric OH, although the extent of OH variations due to each factor depends on the model being examined. This study demonstrates that NNs can serve as a useful tool for quantifying why tropospheric OH varies between global models, provided that essential chemical fields are archived.

  15. Observation of OH radicals produced by pulsed discharges on the surface of a liquid

    Science.gov (United States)

    Kanazawa, Seiji; Kawano, Hirokazu; Watanabe, Satoshi; Furuki, Takashi; Akamine, Shuichi; Ichiki, Ryuta; Ohkubo, Toshikazu; Kocik, Marek; Mizeraczyk, Jerzy

    2011-06-01

    The hydroxyl radical (OH) plays an important role in plasma chemistry at atmospheric pressure. OH radicals have a higher oxidation potential compared with other oxidative species such as free radical O, atomic oxygen, hydroperoxyl radical (HO2), hydrogen peroxide(H2O2) and ozone. In this study, surface discharges on liquids (water and its solutions) were investigated experimentally. A pulsed streamer discharge was generated on the liquid surface using a point-to-plane electrode geometry. The primary generation process of OH radicals is closely related to the streamer propagation, and the subsequent secondary process after the discharge has an influence on the chemical reaction. Taking into account the timescale of these processes, we investigated the behavior of OH radicals using two different diagnostic methods. Time evolution of the ground-state OH radicals above the liquid surface after the discharge was observed by a laser-induced fluorescence (LIF) technique. In order to observe the ground-state OH, an OH [A 2∑+(v' = 1) <-- X 2Π(v'' = 0)] system at 282 nm was used. As the secondary process, a portion of OH radicals diffused from gas phase to the liquid surface and dissolved in the liquid. These dissolved OH radicals were measured by a chemical probe method. Terephthalic acid was used as an OH radical trap and fluorescence of the resulting 2-hydroxyterephthalic acid was measured. This paper directly presents visualization of OH radicals over the liquid surface by means of LIF, and indirectly describes OH radicals dissolved in water by means of a chemical method.

  16. Electronic quenching of OH(A) by water in atmospheric pressure plasmas and its influence on the gas temperature determination by OH(A-X) emission

    International Nuclear Information System (INIS)

    Bruggeman, Peter; Schram, Daan C; Iza, Felipe; Kong, Michael G; Guns, Peter; Lauwers, Daniel; Leys, Christophe; Gonzalvo, Yolanda Aranda

    2010-01-01

    In this paper it is shown that electronic quenching of OH(A) by water prevents thermalization of the rotational population distribution of OH(A). This means that the observed ro-vibrational OH(A-X) emission band is (at least partially) an image of the formation process and is determined not only by the gas temperature. The formation of negative ions and clusters for larger water concentrations can contribute to the non-equilibrium. The above is demonstrated in RF excited atmospheric pressure glow discharges in He-water mixtures in a parallel metal plate reactor by optical emission spectroscopy. For this particular case a significant overpopulation of high rotational states appears around 1000 ppm H 2 O in He. The smallest temperature parameter of a non-Boltzmann (two-temperature) distribution fitted to the experimental spectrum of OH(A-X) gives a good representation of the gas temperature. Only the rotational states with the smallest rotational numbers (J ≤ 7) are thermalized and representative for the gas temperature.

  17. Electronic quenching of OH(A) by water in atmospheric pressure plasmas and its influence on the gas temperature determination by OH(A-X) emission

    Energy Technology Data Exchange (ETDEWEB)

    Bruggeman, Peter; Schram, Daan C [Department of Applied Physics, Technische Universiteit Eindhoven, PO Box 513, 5600 MB Eindhoven (Netherlands); Iza, Felipe; Kong, Michael G [Department of Electronic and Electrical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU (United Kingdom); Guns, Peter; Lauwers, Daniel; Leys, Christophe [Department of Applied Physics, Ghent University, Jozef Plateaustraat 22, B-9000 Ghent (Belgium); Gonzalvo, Yolanda Aranda [Plasma and Surface Analysis Division, Hiden Analytical Ltd, 420 Europa Boulevard, Warrington WA5 7UN (United Kingdom)], E-mail: p.j.bruggeman@tue.nl

    2010-02-15

    In this paper it is shown that electronic quenching of OH(A) by water prevents thermalization of the rotational population distribution of OH(A). This means that the observed ro-vibrational OH(A-X) emission band is (at least partially) an image of the formation process and is determined not only by the gas temperature. The formation of negative ions and clusters for larger water concentrations can contribute to the non-equilibrium. The above is demonstrated in RF excited atmospheric pressure glow discharges in He-water mixtures in a parallel metal plate reactor by optical emission spectroscopy. For this particular case a significant overpopulation of high rotational states appears around 1000 ppm H{sub 2}O in He. The smallest temperature parameter of a non-Boltzmann (two-temperature) distribution fitted to the experimental spectrum of OH(A-X) gives a good representation of the gas temperature. Only the rotational states with the smallest rotational numbers (J {<=} 7) are thermalized and representative for the gas temperature.

  18. OH radicals distribution in an Ar-H2O atmospheric plasma jet

    Science.gov (United States)

    Li, L.; Nikiforov, A.; Xiong, Q.; Britun, N.; Snyders, R.; Lu, X.; Leys, C.

    2013-09-01

    Recently, plasma jet systems found numerous applications in the field of biomedicine and treatment of temperature-sensitive materials. OH radicals are one of the main active species produced by these plasmas. Present study deals with the investigation of RF atmospheric pressure plasma jet in terms of OH radicals production by admixture of H2O into argon used as a feed gas. Generation of OH radicals is studied by laser-induced fluorescence spectroscopy. The excitation dynamics of OH radicals induced by the laser photons is studied by time-resolved spectroscopy. It is shown that vibrational and rotational energy transfer processes, which are sensitive to the surrounding species, can lead to the complication in the OH radicals diagnostics at high pressure and have to be considered during experiments. The axial and radial 2D maps of absolute densities of hydroxyl radicals at different water contents are obtained. The highest density of 1.15 × 1020 m-3 is measured in the plasma core for the case of 0.3% H2O. In the x-y-plane, the OH density steeply decreases within a range of ±2 mm from its maximum value down to 1018 m-3. The effect of H2O addition on the generation of OH radicals is investigated and discussed.

  19. Recurring OH Flares towards o Ceti - I. Location and structure of the 1990s' and 2010s' events

    Science.gov (United States)

    Etoka, S.; Gérard, E.; Richards, A. M. S.; Engels, D.; Brand, J.; Le Bertre, T.

    2017-06-01

    We present the analysis of the onset of the new 2010s OH flaring event detected in the OH ground-state main line at 1665 MHz towards o Ceti and compare its characteristics with those of the 1990s' flaring event. This is based on a series of complementary single-dish and interferometric observations both in OH and H2O obtained with the Nançay Radio telescope, the Medicina and Effelsberg Telescopes, the European VLBI Network and (e)Multi-Element Radio Linked Interferometer Network. We compare the overall characteristics of o Ceti's flaring events with those that have been observed towards other thin-shell Miras, and explore the implication of these events with respect to the standard OH circumstellar-envelope model. The role of binarity in the specific characteristics of o Ceti's flaring events is also investigated. The flaring regions are found to be less than ˜400 ± 40 mas (I.e. ≤40 ± 4 au) either side of o Ceti, with seemingly no preferential location with respect to the direction to the companion Mira B. Contrary to the usual expectation that the OH maser zone is located outside the H2O maser zone, the coincidence of the H2O and OH maser velocities suggests that both emissions arise at similar distances from the star. The OH flaring characteristics of Mira are similar to those observed in various Mira variables before, supporting the earlier results that the regions where the transient OH maser emission occurs are different from the standard OH maser zone.

  20. Amperometric glucose sensor based on the Ni(OH){sub 2}/Al(OH){sub 4}{sup −} electrode obtained from a thin Ni{sub 3}Al foil

    Energy Technology Data Exchange (ETDEWEB)

    Jarosz, Magdalena, E-mail: jarosz@chemia.uj.edu.pl [Department of Physical Chemistry and Electrochemistry, Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30060 Krakow (Poland); Socha, Robert P. [Jerzy Haber Institute of Catalysis and Surface Chemistry Polish Academy of Sciences, Niezapominajek 8, 30239 Krakow (Poland); Jóźwik, Paweł [Faculty of Advanced Technology and Chemistry, Military University of Technology, Kaliskiego 2, 00908 Warsaw (Poland); Sulka, Grzegorz D. [Department of Physical Chemistry and Electrochemistry, Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30060 Krakow (Poland)

    2017-06-30

    Highlights: • Chemical etching of Ni{sub 3}Al alloy in an acidic mixture was performed. • Electrochemical activity of samples was achieved by their oxidation in NaOH. • Ni(OH){sub 2}/Al(OH){sub 4}{sup −} electrode showed electrochemical activity towards glucose. • Synthesized material is characterized by high sensitivity and short response time. - Abstract: In this report, we present a facile and relatively fast method to roughen the surface of Ni{sub 3}Al–based intermetallic foil, and test it as an amperometric non-enzymatic glucose sensor. The alloy samples underwent chemical etching in a H{sub 3}PO{sub 4}:CH{sub 3}COOH (HAc):HNO{sub 3}:H{sub 2}O (24:1:1:7 in volume) solution in order to achieve a high surface area with more electroactive sites. The Ni(OH){sub 2}/Al(OH){sub 4}{sup −} electrode was fabricated using potential cycling technique in a highly concentrated alkaline solution. The electrodes were tested electrochemically for oxidation of glucose. We have demonstrated that Ni(OH){sub 2}/Al(OH){sub 4}{sup −} electrodes exhibit high sensitivity towards glucose detection (796 μAmM{sup -1}cm{sup -2}) and short response time (3 s) upon successive addition of glucose. Moreover, as for a non-nanometric material, prepared electrodes show a relatively good linear correlation between current density and glucose concentration (0.025–0.45 mM) and limit of detection (47.6 μM). For more in-depth characterization of presented material, electrodes were examined using scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS).

  1. Evaluation of a Russian version of the oral health literacy instrument (OHLI).

    Science.gov (United States)

    Blizniuk, Anastasiya; Ueno, Masayuki; Furukawa, Sayaka; Kawaguchi, Yoko

    2014-11-27

    Oral health literacy has become a popular research area in the last decade; however, to date no health literacy instruments in the Russian language exist. The objectives of this study were to develop a Russian version of the Oral Health Literacy Instrument (OHLI) and to examine its reliability and validity. A convenience sample of patients who visited the dental division of the district hospital in Belarus was used in the study. The OHLI, created originally in English, was modified to adapt it to characteristics of routine dental services in Belarus and then translated into Russian, followed by back-translation. Participants completed a self-administered socio-demographic questionnaire, an oral health knowledge test and the Russian version of the OHLI (R-OHLI). Bivariate and multivariate statistical analyses, including multiple regression modeling, were performed to examine reliability and validity of the R-OHLI. Participants were 281 adult patients aged from 18 to 60 years, with a mean age of 33.1 ± 12.2; 64.1% of them were women. Cronbach's alpha values for the two sections (reading comprehension and numeracy) and the total R-OHLI were 0.853, 0.815 and 0.895, respectively. The mean total R-OHLI score was 77.2 ± 14.5; the mean reading comprehension and numeracy scores were 39.5 ± 7.5 and 37.8 ± 8.8, respectively. The R-OHLI was significantly correlated to the oral health knowledge test. Pearson's correlation coefficients between the oral health knowledge test and the reading comprehension, numeracy and total R-OHLI were 0.401, 0.258, and 0.363, respectively (p literacy instrument for Russian-speaking people.

  2. The OH-initiated atmospheric chemical reactions of polyfluorinated dibenzofurans and polychlorinated dibenzofurans: A comparative theoretical study.

    Science.gov (United States)

    Zeng, Xiaolan; Chen, Jing; Qu, Ruijuan; Pan, Xiaoxue; Wang, Zunyao

    2017-02-01

    The atmospheric chemical reactions of some polyfluorinated dibenzofurans (PFDFs) and polychlorinated dibenzofurans (PCDFs), initiated by OH radical, were investigated by performing theoretical calculations using density functional theory (DFT) and B3LYP/6-311++G(2df,p) method. The obtained results indicate that OH addition reactions of PFDFs and PCDFs occurring at C 1∼4 and C A sites are thermodynamic spontaneous changes and the branching ratio of the PF(C)DF-OH adducts is decided primarily by kinetic factor. The OH addition reactions of PFDFs taking place at fluorinated C 1∼4 positions are kinetically comparable with those occurring at nonfluorinated C 1∼4 positions, while OH addition reactions of PCDFs occurring at chlorinated C 1∼4 sites are negligible. The total rate constants of the addition reactions of PFDFs or PCDFs become smaller with consecutive fluorination or chlorination, and substituting at C 1 position has more adverse effects than substitution at other sites. The succedent O 2 addition reactions of PF(C)DF-OH adducts are thermodynamic nonspontaneous processes under the atmospheric conditions, and have high Gibbs free energies of activation (Δ r G ≠ ). The substituted dibenzofuranols are the primary oxidation products for PCDFs under the atmospheric conditions. However, other oxidative products may also be available for PFDFs besides substituted dibenzofuranols. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Observation of OH radicals produced by pulsed discharges on the surface of a liquid

    Energy Technology Data Exchange (ETDEWEB)

    Kanazawa, Seiji; Kawano, Hirokazu; Watanabe, Satoshi; Furuki, Takashi; Akamine, Shuichi; Ichiki, Ryuta; Ohkubo, Toshikazu [Department of Electrical and Electronic Engineering, Oita University, 700 Dannoharu, Oita 870-1192 (Japan); Kocik, Marek; Mizeraczyk, Jerzy, E-mail: skana@cc.oita-u.ac.jp [Szewalski Institute of Fluid Flow Machinery, Polish Academy of Sciences Fiszera 14, 80-952, Gdansk (Poland)

    2011-06-15

    The hydroxyl radical (OH) plays an important role in plasma chemistry at atmospheric pressure. OH radicals have a higher oxidation potential compared with other oxidative species such as free radical O, atomic oxygen, hydroperoxyl radical (HO{sub 2}), hydrogen peroxide(H{sub 2}O{sub 2}) and ozone. In this study, surface discharges on liquids (water and its solutions) were investigated experimentally. A pulsed streamer discharge was generated on the liquid surface using a point-to-plane electrode geometry. The primary generation process of OH radicals is closely related to the streamer propagation, and the subsequent secondary process after the discharge has an influence on the chemical reaction. Taking into account the timescale of these processes, we investigated the behavior of OH radicals using two different diagnostic methods. Time evolution of the ground-state OH radicals above the liquid surface after the discharge was observed by a laser-induced fluorescence (LIF) technique. In order to observe the ground-state OH, an OH [A {sup 2}{Sigma}{sup +}(v' = 1) <- X {sup 2}{Pi}(v'' = 0)] system at 282 nm was used. As the secondary process, a portion of OH radicals diffused from gas phase to the liquid surface and dissolved in the liquid. These dissolved OH radicals were measured by a chemical probe method. Terephthalic acid was used as an OH radical trap and fluorescence of the resulting 2-hydroxyterephthalic acid was measured. This paper directly presents visualization of OH radicals over the liquid surface by means of LIF, and indirectly describes OH radicals dissolved in water by means of a chemical method.

  4. A STUDY OF RO-VIBRATIONAL OH EMISSION FROM HERBIG Ae/Be STARS

    Energy Technology Data Exchange (ETDEWEB)

    Brittain, Sean D.; Reynolds, Nickalas [Department of Physics and Astronomy, 118 Kinard Laboratory, Clemson University, Clemson, SC 29634-0978 (United States); Najita, Joan R. [National Optical Astronomy Observatory, 950 N. Cherry Ave., Tucson, AZ 85719 (United States); Carr, John S. [Naval Research Laboratory, Code 7211, Washington, DC 20375 (United States); Ádámkovics, Máté, E-mail: sbritt@clemson.edu [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)

    2016-10-20

    We present a study of ro-vibrational OH and CO emission from 21 disks around Herbig Ae/Be stars. We find that the OH and CO luminosities are proportional over a wide range of stellar ultraviolet luminosities. The OH and CO line profiles are also similar, indicating that they arise from roughly the same radial region of the disk. The CO and OH emission are both correlated with the far-ultraviolet luminosity of the stars, while the polycyclic aromatic hydrocarbon (PAH) luminosity is correlated with the longer wavelength ultraviolet luminosity of the stars. Although disk flaring affects the PAH luminosity, it is not a factor in the luminosity of the OH and CO emission. These properties are consistent with models of UV-irradiated disk atmospheres. We also find that the transition disks in our sample, which have large optically thin inner regions, have lower OH and CO luminosities than non-transition disk sources with similar ultraviolet luminosities. This result, while tentative given the small sample size, is consistent with the interpretation that transition disks lack a gaseous disk close to the star.

  5. Potent inhibition of rhabdoid tumor cells by combination of flavopiridol and 4OH-tamoxifen

    International Nuclear Information System (INIS)

    Cimica, Velasco; Smith, Melissa E; Zhang, Zhikai; Mathur, Deepti; Mani, Sridhar; Kalpana, Ganjam V

    2010-01-01

    Rhabdoid Tumors (RTs) are highly aggressive pediatric malignancies with poor prognosis. There are currently no standard or effective treatments for RTs in part because treatments are not designed to specifically target these tumors. Our previous studies indicated that targeting the cyclin/cdk pathway is a novel therapeutic strategy for RTs and that a pan-cdk inhibitor, flavopiridol, inhibits RT growth. Since the toxicities and narrow window of activity associated with flavopiridol may limit its clinical use, we tested the effect of combining flavopiridol with 4-hydroxy-Tamoxifen (4OH-Tam) in order to reduce the concentration of flavopiridol needed for inhibition of RTs. The effects of flavopiridol, 4OH-Tam, and their combination on RT cell cycle regulation and apoptosis were assessed by: i) cell survival assays, ii) FACS analysis, iii) caspase activity assays, and iv) immunoblot analysis. Furthermore, the role of p53 in flavopiridol- and 4OH-Tam-mediated induction of cell cycle arrest and apoptosis was characterized using RNA interference (siRNA) analysis. The effect of p53 on flavopiridol-mediated induction of caspases 2, 3, 8 and 9 was also determined. We found that the combination of flavopiridol and 4OH-Tam potently inhibited the growth of RT cells. Low nanomolar concentrations of flavopiridol induced G 2 arrest, which was correlated to down-modulation of cyclin B1 and up-regulation of p53. Addition of 4OH-Tam did not affect flavopiridol-mediated G 2 arrest, but enhanced caspase 3,7-mediated apoptosis induced by the drug. Abrogation of p53 by siRNA abolished flavopiridol-induced G 2 arrest, but enhanced flavopiridol- (but not 4OH-Tam-) mediated apoptosis, by enhancing caspase 2 and 3 activities. Combining flavopiridol with 4OH-Tam potently inhibited the growth of RT cells by increasing the ability of either drug alone to induce caspases 2 and 3 thereby causing apoptosis. The potency of flavopiridol was enhanced by abrogation of p53. Our results warrant further

  6. Potent inhibition of rhabdoid tumor cells by combination of flavopiridol and 4OH-tamoxifen

    Energy Technology Data Exchange (ETDEWEB)

    Cimica, Velasco; Smith, Melissa E; Zhang, Zhikai; Mathur, Deepti [Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461 (United States); Mani, Sridhar [Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461 (United States); Department of Medicine, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461 (United States); Albert Einstein Cancer Center, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461 (United States); Kalpana, Ganjam V [Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461 (United States); Albert Einstein Cancer Center, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461 (United States)

    2010-11-19

    Rhabdoid Tumors (RTs) are highly aggressive pediatric malignancies with poor prognosis. There are currently no standard or effective treatments for RTs in part because treatments are not designed to specifically target these tumors. Our previous studies indicated that targeting the cyclin/cdk pathway is a novel therapeutic strategy for RTs and that a pan-cdk inhibitor, flavopiridol, inhibits RT growth. Since the toxicities and narrow window of activity associated with flavopiridol may limit its clinical use, we tested the effect of combining flavopiridol with 4-hydroxy-Tamoxifen (4OH-Tam) in order to reduce the concentration of flavopiridol needed for inhibition of RTs. The effects of flavopiridol, 4OH-Tam, and their combination on RT cell cycle regulation and apoptosis were assessed by: i) cell survival assays, ii) FACS analysis, iii) caspase activity assays, and iv) immunoblot analysis. Furthermore, the role of p53 in flavopiridol- and 4OH-Tam-mediated induction of cell cycle arrest and apoptosis was characterized using RNA interference (siRNA) analysis. The effect of p53 on flavopiridol-mediated induction of caspases 2, 3, 8 and 9 was also determined. We found that the combination of flavopiridol and 4OH-Tam potently inhibited the growth of RT cells. Low nanomolar concentrations of flavopiridol induced G{sub 2} arrest, which was correlated to down-modulation of cyclin B1 and up-regulation of p53. Addition of 4OH-Tam did not affect flavopiridol-mediated G{sub 2} arrest, but enhanced caspase 3,7-mediated apoptosis induced by the drug. Abrogation of p53 by siRNA abolished flavopiridol-induced G{sub 2} arrest, but enhanced flavopiridol- (but not 4OH-Tam-) mediated apoptosis, by enhancing caspase 2 and 3 activities. Combining flavopiridol with 4OH-Tam potently inhibited the growth of RT cells by increasing the ability of either drug alone to induce caspases 2 and 3 thereby causing apoptosis. The potency of flavopiridol was enhanced by abrogation of p53. Our results

  7. Potent inhibition of rhabdoid tumor cells by combination of flavopiridol and 4OH-tamoxifen

    Directory of Open Access Journals (Sweden)

    Mani Sridhar

    2010-11-01

    Full Text Available Abstract Background Rhabdoid Tumors (RTs are highly aggressive pediatric malignancies with poor prognosis. There are currently no standard or effective treatments for RTs in part because treatments are not designed to specifically target these tumors. Our previous studies indicated that targeting the cyclin/cdk pathway is a novel therapeutic strategy for RTs and that a pan-cdk inhibitor, flavopiridol, inhibits RT growth. Since the toxicities and narrow window of activity associated with flavopiridol may limit its clinical use, we tested the effect of combining flavopiridol with 4-hydroxy-Tamoxifen (4OH-Tam in order to reduce the concentration of flavopiridol needed for inhibition of RTs. Methods The effects of flavopiridol, 4OH-Tam, and their combination on RT cell cycle regulation and apoptosis were assessed by: i cell survival assays, ii FACS analysis, iii caspase activity assays, and iv immunoblot analysis. Furthermore, the role of p53 in flavopiridol- and 4OH-Tam-mediated induction of cell cycle arrest and apoptosis was characterized using RNA interference (siRNA analysis. The effect of p53 on flavopiridol-mediated induction of caspases 2, 3, 8 and 9 was also determined. Results We found that the combination of flavopiridol and 4OH-Tam potently inhibited the growth of RT cells. Low nanomolar concentrations of flavopiridol induced G2 arrest, which was correlated to down-modulation of cyclin B1 and up-regulation of p53. Addition of 4OH-Tam did not affect flavopiridol-mediated G2 arrest, but enhanced caspase 3,7-mediated apoptosis induced by the drug. Abrogation of p53 by siRNA abolished flavopiridol-induced G2 arrest, but enhanced flavopiridol- (but not 4OH-Tam- mediated apoptosis, by enhancing caspase 2 and 3 activities. Conclusions Combining flavopiridol with 4OH-Tam potently inhibited the growth of RT cells by increasing the ability of either drug alone to induce caspases 2 and 3 thereby causing apoptosis. The potency of flavopiridol was

  8. Few-layered Ni(OH)2 nanosheets for high-performance supercapacitors

    Science.gov (United States)

    Sun, Wenping; Rui, Xianhong; Ulaganathan, Mani; Madhavi, Srinivasan; Yan, Qingyu

    2015-11-01

    Few-layered Ni(OH)2 nanosheets (4-5 nm in thickness) are synthesized towards high-performance supercapacitors. The ultrathin Ni(OH)2 nanosheets show high specific capacitance and good rate capability in both three-electrode and asymmetric devices. In the three-electrode device, the Ni(OH)2 nanosheets deliver a high capacitance of 2064 F g-1 at 2 A g-1, and the capacitance still has a retention of 1837 F g-1 at a high current density of 20 A g-1. Such excellent performance is by far one of the best for Ni(OH)2 electrodes. In the two-electrode asymmetric device, the specific capacitance is 248 F g-1 at 1 A g-1, and reaches 113 F g-1 at 20 A g-1. The capacitance of the asymmetric device maintains to be 166 F g-1 during the 4000th cycle at 2 A g-1, suggesting good cycling stability of the device. Besides, the asymmetric device exhibits gravimetric energy density of 22 Wh kg-1 at a power density of 0.8 kW kg-1. The present results demonstrate that the ultrathin Ni(OH)2 nanosheets are highly attractive electrode materials for achieving fast charging/discharging and high-capacity supercapacitors.

  9. AN ARECIBO SURVEY FOR ZEEMAN SPLITTING IN OH MEGAMASER GALAXIES

    International Nuclear Information System (INIS)

    McBride, James; Heiles, Carl

    2013-01-01

    We present the results of a comprehensive survey using the Arecibo Observatory for Zeeman splitting of OH lines in OH megamasers (OHMs). A total of 77 sources were observed with the Arecibo telescope. Of these, maser emission could not be detected for eight sources, and two sources were only ambiguously detected. Another 27 sources were detected at low signal-to-noise ratios or with interference that prevented placing any useful limits on the presence of magnetic fields. In 26 sources, it was possible to place upper limits on the magnitude of magnetic fields, typically between 10 and 30 mG. For 14 sources, the Stokes V spectra exhibit features consistent with Zeeman splitting. Eleven of these 14 are new detections, and the remaining three are re-detections of Stokes V detections in Robishaw et al. Among confident new detections, we derive magnetic fields associated with maser regions with magnitudes ranging from 6.1 to 27.6 mG. The distribution of magnetic field strengths suggests the magnetic fields in OH masing clouds in OHMs are larger than those in Galactic OH masers. The results are consistent with magnetic fields playing a dynamically important role in OH masing clouds in OHMs.

  10. EnviroAtlas - Cleveland, OH - Block Groups

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset is the base layer for the Cleveland, OH EnviroAtlas community. The block groups are from the US Census Bureau and are included/excluded...

  11. Mechanism of the CO2-Ca(OH)2 reaction

    International Nuclear Information System (INIS)

    Chew, V.S.; Cheh, C.H.; Glass, R.W.

    1983-01-01

    Recent studies clearly showed the importance of moisture in achieving high Ca(OH) 2 absorbent utilization for removing CO 2 from gas streams at ambient temperatures. However, the role of moisture and the mechanism of the reaction was not well understood. This paper summarizes the results of a study of the mechanism of the CO 2 -Ca(OH) 2 reaction with emphasis on the role of moisture. The reaction between Ca(OH) 2 and CO 2 in moist N 2 was found to be first order with respect to the reactants with a rate constant of about 100 min -1 . At high humidities, the rate of reaction was chemically controlled, but at low humidities, the reaction rate was limited by the diffusion through the carbonate layer formed by the reaction. Calculations showed that capillary condensation could have occurred only in about 2% of the pore volume and was unlikely to have affected the reaction rate significantly by allowing the reaction to occur in the liquid phase. It was, therefore, concluded that the main role of moisture was to improve the Ca(OH) 2 utilization by lowering the resistance to diffusion through the carbonate layer

  12. The OHS consultant as a facilitator of learning in workplace design processes

    DEFF Research Database (Denmark)

    Broberg, Ole; Hermund, Ingelise

    2007-01-01

    Occupational health service (OHS) consultancy on workplace design proc-esses in client enterprises is expected also to entail some elements of learn-ing. When the OHS consultant has performed the task the enterprise should have learned something on how to integrate health and safety aspects...... into the workplace design process, thereby making it easier for the enterprise to manage such a change in the future. The objective of this explorative study was to survey current practice of OHS consultants and put forward recom-mendations on how to improve the learning aspects of OHS consultancy. Four cases were...... devices between different communities of practice. Certain boundary objects work better than others in promoting learning and collaborative workplace design processes. For both industry and OHS units it is of importance to properly understand learning models and to align their mutual expectations...

  13. Characterization Of Mg(OH)2 Precipitation On MSF Desalination Process

    International Nuclear Information System (INIS)

    Sumijanto

    2000-01-01

    The experiment of Mg(OH) sub.2 precipitation has been carry out. Experiment took please by heating sea water simulation with consist of 142 ppm bicarbonate and magnesium ion at temperature 40, 50, 60, 70, 80, 90, 100, 110, and 120 exp.oC respectively by using autoclave. Sampling has been done periodical for 30 minute in interval 300 minute for each temperature. The calculation of Mg(OH) sub.2 precipitation through the decreasing of magnesium concentration with analysis by AAS. From experiment data have the information that Mg(OH) sub.2 precipitation have been formed since 40 exp.oC. From time variable have been the information that the precipitation formed at 30th minute rapidly. Whether at further time the increasing of precipitation are not significant. This phenomena can explained that at each heating step from 40 exp.oC bicarbonate ion be come decomposition with the result carbonate and hydroxide ion and react with magnesium form Mg(OH) sub.2

  14. Numerical model of Ca(OH)

    NARCIS (Netherlands)

    Koster, T.; Peelen, W.; Larbi, J.; Rooij, M. de; Polder, R.

    2010-01-01

    A mathematical model is being developed to describe a repair method in concrete, called cathodic protection (CP). The model is in principle also useful to describe electrodeposition in concrete, e.g. the process of re-precipitation of Ca(OH)2 invoked by an electrical current. In CP, the

  15. Room temperature chemical synthesis of Cu(OH){sub 2} thin films for supercapacitor application

    Energy Technology Data Exchange (ETDEWEB)

    Gurav, K.V. [Thin Film Photonic and Electronics Lab, Department of Materials Science and Engineering, Chonnam National University, 300 Yongbong-dong, Puk-Gu, Gwangju 500-757 (Korea, Republic of); Patil, U.M. [Thin Film Physics Laboratory, Department of Physics, Shivaji University, Kolhapur 416 007 (M.S.) (India); Shin, S.W.; Agawane, G.L.; Suryawanshi, M.P.; Pawar, S.M.; Patil, P.S. [Thin Film Photonic and Electronics Lab, Department of Materials Science and Engineering, Chonnam National University, 300 Yongbong-dong, Puk-Gu, Gwangju 500-757 (Korea, Republic of); Lokhande, C.D. [Thin Film Physics Laboratory, Department of Physics, Shivaji University, Kolhapur 416 007 (M.S.) (India); Kim, J.H., E-mail: jinhyeok@chonnam.ac.kr [Thin Film Photonic and Electronics Lab, Department of Materials Science and Engineering, Chonnam National University, 300 Yongbong-dong, Puk-Gu, Gwangju 500-757 (Korea, Republic of)

    2013-10-05

    Highlights: •Cu(OH){sub 2} is presented as the new supercapacitive material. •The novel room temperature method used for the synthesis of Cu(OH){sub 2}. •The hydrous, nanograined Cu(OH){sub 2} shows higher specific capacitance of 120 F/g. -- Abstract: Room temperature soft chemical synthesis route is used to grow nanograined copper hydroxide [Cu(OH){sub 2}] thin films on glass and stainless steel substrates. The structural, morphological, optical and wettability properties of Cu(OH){sub 2} thin films are studied by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), UV–vis spectrophotometer and water contact angle measurement techniques. The results showed that, room temperature chemical synthesis route allows to form the nanograined and hydrophilic Cu(OH){sub 2} thin films with optical band gap energy of 3.0 eV. The electrochemical properties of Cu(OH){sub 2} thin films are studied in an aqueous 1 M NaOH electrolyte using cyclic voltammetry. The sample exhibited supercapacitive behavior with 120 F/g specific capacitance.

  16. Inhibition of human placental aromatase activity by hydroxylated polybrominated diphenyl ethers (OH-PBDEs).

    Science.gov (United States)

    Cantón, Rocío F; Scholten, Deborah E A; Marsh, Göran; de Jong, Paul C; van den Berg, Martin

    2008-02-15

    Polybrominated diphenyl ethers (PBDEs) are widely used as flame retardants in many different polymers, resins and substrates. Due to their widespread production and use, their high binding affinity to particles, and their lipophilic properties, several PBDE congeners can bioaccumulate in the environment. As a result, PBDEs and their hydroxylated metabolites (OH-PBDEs) have been detected in humans and various wildlife samples, such as birds, seals, and whales. Furthermore, certain OH-PBDEs and their methoxylated derivatives (MeO-PBDEs) are natural products in the marine environment. Recently, our laboratory focused on the possible effects on steroidogenesis of PBDEs and OH-PBDEs, e.g. in the human adrenocortical carcinoma (H295R) cell line indicating that some OH-PBDEs can significantly influence steroidogenic enzymes like CYP19 (aromatase) and CYP17. In the present study, human placental microsomes have been used to study the possible interaction of twenty two OH-PBDEs and MeO-PBDEs with aromatase, the enzyme that mediates the conversion of androgens into estrogens. All OH-PBDE derivates showed significant inhibition of placental aromatase activity with IC(50) values in the low micromolar range, while the MeO-PBDEs did not have any effect on this enzyme activity. Enzyme kinetics studies indicated that two OH-PBDEs, 5-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (5-OH-BDE47) and 6-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (6-OH-BDE47), had a mixed-type inhibition of aromatase activity with apparent K(i)/K(i)' of 7.68/0,02 microM and 5.01/0.04 microM respectively. For comparison, some structurally related compounds, a dihydroxylated polybrominated biphenyl, which is a natural product (2,2'-dihyroxy-3,3',5,5'-tetrabromobiphenyl (2,2'-diOH-BB80)) and its non-bromo derivative were also included in the study. Again inhibition of aromatase activity could be measured, but their potency was significantly less than those observed for the OH-PBDEs. These results show that a

  17. Inhibition of human placental aromatase activity by hydroxylated polybrominated diphenyl ethers (OH-PBDEs)

    International Nuclear Information System (INIS)

    Canton, Rocio F.; Scholten, Deborah E.A.; Marsh, Goeran; Jong, Paul C. de; Berg, Martin van den

    2008-01-01

    Polybrominated diphenyl ethers (PBDEs) are widely used as flame retardants in many different polymers, resins and substrates. Due to their widespread production and use, their high binding affinity to particles, and their lipophilic properties, several PBDE congeners can bioaccumulate in the environment. As a result, PBDEs and their hydroxylated metabolites (OH-PBDEs) have been detected in humans and various wildlife samples, such as birds, seals, and whales. Furthermore, certain OH-PBDEs and their methoxylated derivatives (MeO-PBDEs) are natural products in the marine environment. Recently, our laboratory focused on the possible effects on steroidogenesis of PBDEs and OH-PBDEs, e.g. in the human adrenocortical carcinoma (H295R) cell line indicating that some OH-PBDEs can significantly influence steroidogenic enzymes like CYP19 (aromatase) and CYP17. In the present study, human placental microsomes have been used to study the possible interaction of twenty two OH-PBDEs and MeO-PBDEs with aromatase, the enzyme that mediates the conversion of androgens into estrogens. All OH-PBDE derivates showed significant inhibition of placental aromatase activity with IC 50 values in the low micromolar range, while the MeO-PBDEs did not have any effect on this enzyme activity. Enzyme kinetics studies indicated that two OH-PBDEs, 5-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (5-OH-BDE47) and 6-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (6-OH-BDE47), had a mixed-type inhibition of aromatase activity with apparent K i /K i ' of 7.68/0,02 μM and 5.01/0.04 μM respectively. For comparison, some structurally related compounds, a dihydroxylated polybrominated biphenyl, which is a natural product (2,2'-dihyroxy-3,3',5,5'-tetrabromobiphenyl (2,2'-diOH-BB80)) and its non-bromo derivative were also included in the study. Again inhibition of aromatase activity could be measured, but their potency was significantly less than those observed for the OH-PBDEs. These results show that a wide

  18. Formation of titanate nanostructures under different NaOH concentration and their application in wastewater treatment

    International Nuclear Information System (INIS)

    Huang Jiquan; Cao Yongge; Deng Zhonghua; Tong Hao

    2011-01-01

    The effects of the concentration of NaOH on the formation and transformation of various titanate nanostructures were studied. With increasing NaOH concentration, three different formation mechanisms were proposed. Nanotubes can only be obtained under moderate NaOH conditions, and should transform into nanowires with prolonged hydrothermal treatment, and their formation rate is accelerated by increasing NaOH concentration. Low concentration of NaOH results in the direct formation of nanowires, while extra high concentration of NaOH leads to the formation of amorphous nanoparticles. Adsorption and photocatalysis studies show that titanate nanowires and nanotubes might be potential adsorbents for the removal of both heavy metal ions and dyes and photocatalysts for the removal of dyes from wastewater. -- Graphical abstract: The morphologies of the titanates depend deeply on the concentration of NaOH. With increasing NaOH concentration, three different formation mechanisms were proposed. The application of these titanate nanostructures in the wastewater treatment was studied. Display Omitted Research highlights: → Effect of NaOH concentration on the structures of various titanates was reported. → Three different formation mechanisms were presented with increasing NaOH concentration. → Various titanates were used as adsorbents/photocatalysts in wastewater treatment.

  19. Stokes polarimetry of main-line OH emission from stellar masers

    International Nuclear Information System (INIS)

    Claussen, M.J.; Fix, J.D.

    1982-01-01

    Main-line OH emission has been measured in all four Stokes parameters from seven late-type variable stars and the F8 supergiant IRC+10420. Linearly polarized features were detected in UX Cyg, U Ori, and IRC+10420 at 1665 MHz. The linearly polarized features in UX Cyg and IRC +10420, when combined with adjacent circularly polarized features suggest Zeeman patterns. A polarization pattern in IRC+10420 is probably the best example of a complete Zeeman pattern yet observed in stellar masers, although it appears to lack the shifted linear (sigma) components. This study, combined with other recent work, shows that linearly polarized features in stellar sources are uncommon. Only about 10% of the stellar OH sources show linearly polarized features. As an aid in accounting for the observed polarization properties of stellar OH masers, model mass flows were calculated using magnetic field structures similar to that of the solar wind. Conclusions drawn from this model were: (1) unpolarized or weakly circularly polarized emission from sources can arise from the entire circumstellar shell; (2) circular polarization without linear polarization can be produced either by emission from the entire shell or by enhanced OH densities in small regions of the shell provided there are sufficient free electrons present to depolarize the linear components; and (3) Zeeman patterns which include both circular and linear polarizations can be produced in OH density enhancements if electron densities are low. The electron densities required for effective Faraday depolarization yield emission measures of the order of 10 9 pc cm -6 . Given the large distances of stellar OH masers, the thermal continuum emission from such depolarizing electrons would probably be undetectable

  20. New insights into the intercalation chemistry of Al(OH)3.

    Science.gov (United States)

    Williams, Gareth R; Moorhouse, Saul J; Prior, Timothy J; Fogg, Andrew M; Rees, Nicholas H; O'Hare, Dermot

    2011-06-14

    This paper reports a number of recent developments in the intercalation chemistry of Al(OH)(3). From Rietveld refinement and solid-state NMR, it has been possible to develop a structural model for the recently reported [M(II)Al(4)(OH)(12)](NO(3))(2)·yH(2)O family of layered double hydroxides (LDHs). The M(2+) cations occupy half of the octahedral holes in the Al(OH)(3) layers, and it is thought that there is complete ordering of the metal ions while the interlayer nitrate anions are highly disordered. Filling the remainder of the octahedral holes in the layers proved impossible. While the intercalation of Li salts into Al(OH)(3) is facile, it was found that the intercalation of M(II) salts is much more capricious. Only with Co, Ni, Cu, and Zn nitrates and Zn sulfate were phase-pure LDHs produced. In other cases, there is either no reaction or a phase believed to be an LDH forms concomitantly with impurity phases. Reacting Al(OH)(3) with mixtures of M(II) salts can lead to the production of three-metal M(II)-M(II)'-Al LDHs, but it is necessary to control precisely the starting ratios of the two M(II) salts in the reaction gel because Al(OH)(3) displays selective intercalation of M nitrate (Li > Ni > Co ≈ Zn). The three-metal M(II)-M(II)'-Al LDHs exhibit facile ion exchange intercalation, which has been investigated in the first energy dispersive X-ray diffraction study of a chemical reaction system performed on Beamline I12 of the Diamond Light Source.

  1. Thermodynamic Mixing Behavior Of F-OH Apatite Crystalline Solutions

    Science.gov (United States)

    Hovis, G. L.

    2011-12-01

    It is important to establish a thermodynamic data base for accessory minerals and mineral series that are useful in determining fluid composition during petrologic processes. As a starting point for apatite-system thermodynamics, Hovis and Harlov (2010, American Mineralogist 95, 946-952) reported enthalpies of mixing for a F-Cl apatite series. Harlov synthesized all such crystalline solutions at the GFZ-Potsdam using a slow-cooled molten-flux method. In order to expand thermodynamic characterization of the F-Cl-OH apatite system, a new study has been initiated along the F-OH apatite binary. Synthesis of this new series made use of National Institute of Standards and Technology (NIST) 2910a hydroxylapatite, a standard reference material made at NIST "by solution reaction of calcium hydroxide with phosphoric acid." Synthesis efforts at Lafayette College have been successful in producing fluorapatite through ion exchange between hydroxylapatite 2910a and fluorite. In these experiments, a thin layer of hydroxylapatite powder was placed on a polished CaF2 disc (obtained from a supplier of high-purity crystals for spectroscopy), pressed firmly against the disc, then annealed at 750 °C (1 bar) for three days. Longer annealing times did not produce further change in unit-cell dimensions of the resulting fluorapatite, but it is uncertain at this time whether this procedure produces a pure-F end member (chemical analyses to be performed in the near future). It is clear from the unit-cell dimensions, however, that the newly synthesized apatite contains a high percentage of fluorine, probably greater than 90 mol % F. Intermediate compositions for a F-OH apatite series were made by combining 2910a hydroxylapatite powder with the newly synthesized fluorapatite in various proportions, then conducting chemical homogenization experiments at 750 °C on each mixture. X-ray powder diffraction data indicated that these experiments were successful in producing chemically homogeneous

  2. Emission of OH* and CO2* during the high-temperature oxidation of acetone in reflected shock waves

    Science.gov (United States)

    Tereza, A. M.; Smirnov, V. N.; Vlasov, P. A.; Shumova, V. V.; Garmash, A. A.

    2018-01-01

    Experimental and kinetic modeling study of the ignition of a stoichiometric mixture of acetone with oxygen diluted by argon was carried out behind reflected shock waves within the temperature range of 1350-1810 K for the total mixture concentration [M 50] ~ 10-5 mol/cm3. Emission signals were recorded simultaneously for three different wavelengths: OH* (λ = 308 nm) and {{{CO}}}2* (λ1 = 365 nm; λ2 = 451 nm). It was revealed that the time it takes to reach the maximum of emission of OH* and {{{CO}}}2* is practically the same over the whole temperature range. At the same time, the emission profiles of {{{CO}}}2* after the maximum was attained, recorded at λ2 = 451 nm, differ noticeably from the profiles recorded at λ1 = 365 nm. For numerical modeling of the emission profiles of OH* and {{{CO}}}2* , the corresponding sets of excitation and quenching reactions available in the literature were used. In the course of our numerical simulations we succeeded in good agreement of our own experimental and simulation results on acetone ignition and the results available in the literature for conditions under consideration.

  3. Antimicrobial activity study of a μ3-oxo bridged [Fe3O(PhCO2)6(MeOH)3](NO3)(MeOH)2] cluster

    Science.gov (United States)

    Pathak, Sayantan; Jana, Barun; Mandal, Manab; Mandal, Vivekananda; Ghorai, Tanmay K.

    2017-11-01

    Synthesis, characterization and antimicrobial activity of a tri-nuclear μ3-Oxobridged Fe(III) cluster [Fe3O(PhCO2)6(MeOH)3](NO3)(MeOH)2(1) is reported. Cluster 1 is synthesized in a single pot reaction among Fe(NO3)3·9H2O, C6H5COOH, NaN3 (1:4:1) in MeOH. Single crystal X-ray diffraction studies of the isolated crystals show that it is μ3-Oxo bridged trimeric assembly of three Fe atoms via bridging benzoate anions. Furthermore, BVS calculations show that all three Fe atoms in complex 1 are in +3 oxidation state and are surrounded by benzoate anions and methanol in octahedral environment. The oxidation state of iron is also confirmed from the cyclic voltamogram. FT-IR spectroscopy and CHN analysis of the isolated crystals further supports the functional group attached to the periphery of the complex. The nanomolecular size of complex 1 is 1.29 nm. The antimicrobial efficiency studies of the complex 1 show significant inhibition of the growth of the organisms, viz. B. cereus MTCC 1272, S. epidermidis MTCC 3086 and S. typhimurium MTCC 98 and produced 23 ± 1.93 mm, 16 ± 1.77 mm and 12 ± 2.42 mm inhibition zones respectively. However, it shows zero inhibition to the strain of E. coli MTCC 723.

  4. Gas phase kinetics of the OH + CH3CH2OH reaction at temperatures of the interstellar medium (T = 21-107 K).

    Science.gov (United States)

    Ocaña, A J; Blázquez, S; Ballesteros, B; Canosa, A; Antiñolo, M; Albaladejo, J; Jiménez, E

    2018-02-21

    Ethanol, CH 3 CH 2 OH, has been unveiled in the interstellar medium (ISM) by radioastronomy and it is thought to be released into the gas phase after the warm-up phase of the grain surface, where it is formed. Once in the gas phase, it can be destroyed by different reactions with atomic and radical species, such as hydroxyl (OH) radicals. The knowledge of the rate coefficients of all these processes at temperatures of the ISM is essential in the accurate interpretation of the observed abundances. In this work, we have determined the rate coefficient for the reaction of OH with CH 3 CH 2 OH (k(T)) between 21 and 107 K by employing the pulsed and continuous CRESU (Cinétique de Réaction en Ecoulement Supersonique Uniforme, which means Reaction Kinetics in a Uniform Supersonic Flow) technique. The pulsed laser photolysis technique was used for generating OH radicals, whose time evolution was monitored by laser induced fluorescence. An increase of approximately 4 times was observed for k(21 K) with respect to k(107 K). With respect to k(300 K), the OH-reactivity at 21 K is enhanced by two orders of magnitude. The obtained T-expression in the investigated temperature range is k(T) = (2.1 ± 0.5) × 10 -11 (T/300 K) -(0.71±0.10) cm 3 molecule -1 s -1 . In addition, the pressure dependence of k(T) has been investigated at several temperatures between 21 K and 90 K. No pressure dependence of k(T) was observed in the investigated ranges. This may imply that this reaction is purely bimolecular or that the high-pressure limit is reached at the lowest total pressure experimentally accessible in our system. From our results, k(T) at usual IS temperatures (∼10-100 K) is confirmed to be very fast. Typical rate coefficients can be considered to range within about 4 × 10 -11 cm 3 molecule -1 s -1 at 100 K and around 1 × 10 -10 cm 3 molecule -1 s -1 at 20 K. The extrapolation of k at the lowest temperatures of the dense molecular clouds of ISM is also discussed in this paper.

  5. OH yields from the CH3CO+O-2 reaction using an internal standard\\ud

    OpenAIRE

    Carr, S.A.; Baeza-Romero, M.T.; Blitz, M.A.; Pilling, M.J.; Heard, D.E.; Seakins, P.W.

    2007-01-01

    Laser flash photolysis of CH3C(O)OH at 248 nm was used to create equal zero time yields of CH3CO and OH. The absolute OH yield from the CH3CO + O2 (+M) reaction was determined by following the OH temporal profile using the zero time\\ud OH concentration as an internal standard. The OH yield from CH3CO + O2 (+M) was observed to decrease with increasing pressure with an extrapolated zero pressure yield\\ud close to unity (1.1 ± 0.2, quoted uncertainties correspond to 95% confidence limits). The r...

  6. Genomic analysis of Bacillus subtilis OH 131.1 and coculturing with Cryptococcus flavescens for control of fusarium head blight

    Science.gov (United States)

    Bacillus subtilis OH131.1 is a bacterial antagonist of Fusarium graminearum, a plant pathogen which causes Fusarium head blight in wheat. The genome of B. subtilis OH131.1 was sequenced, annotated and analyzed to understand its potential to produce bioactive metabolites. The analysis identified 6 sy...

  7. Establishment of 25-OH-vitamin D reference interval by radioimmunoassay and its clinical significance

    International Nuclear Information System (INIS)

    Chen Jianbo; Huang Xianzhong; Hu Chaohui; Zu Yuli; Zhu Qingyi

    2009-01-01

    Objective: To establish reference interval of 25-OH-vitamin D (25-OH-Vit D) by radioimmunoassay and provide suggestion for clinical applications. Method: Collecting 204 healthy persons specimens, and validating and establishing reference interval of 25-OH-Vit D by treatment of outlying observations, judgement of data distributions and analysis of test results. Results: The reference interval of 25-OH-Vit D established in our laboratory is 16.0-39.7 ng/ml for adolescents and 11.7-40.0 ng/ml for adults. Conclusions: The levels of 25-OH-Vit D in humans depend on their age, sex and life style. Some people's vitamin D intake is not enough. Doctors should pay attention to the sufficient 25-OH-Vit D needed when evaluate vitamin D intake. (authors)

  8. Nitrate-assisted photocatalytic efficiency of defective Eu-doped Pr(OH)3 nanostructures.

    Science.gov (United States)

    Aškrabić, S; Araújo, V D; Passacantando, M; Bernardi, M I B; Tomić, N; Dojčinović, B; Manojlović, D; Čalija, B; Miletić, M; Dohčević-Mitrović, Z D

    2017-12-06

    Pr(OH) 3 one-dimensional nanostructures are a less studied member of lanthanide hydroxide nanostructures, which recently demonstrated an excellent adsorption capacity for organic pollutant removal from wastewater. In this study, Pr 1-x Eu x (OH) 3 (x = 0, 0.01, 0.03, and 0.05) defective nanostructures were synthesized by a facile and scalable microwave-assisted hydrothermal method using KOH as an alkaline metal precursor. The phase and surface composition, morphology, vibrational, electronic and optical properties of the as-prepared samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectrometry (ICP-OES), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), Raman, infrared (IR), photoluminescence (PL), and diffuse reflectance spectroscopy (DRS). It was deduced that the incorporation of Eu 3+ ions promoted the formation of oxygen vacancies in the already defective Pr(OH) 3 , subsequently changing the Pr(OH) 3 nanorod morphology. The presence of KNO 3 phase was registered in the Eu-doped samples. The oxygen-deficient Eu-doped Pr(OH) 3 nanostructures displayed an improved photocatalytic activity in the removal of reactive orange (RO16) dye under UV-vis light irradiation. An enhanced photocatalytic activity of the Eu-doped Pr(OH) 3 nanostructures was caused by the synergetic effect of oxygen vacancies and Eu 3+ (NO 3 - ) ions present on the Pr(OH) 3 surface, the charge separation efficiency and the formation of the reactive radicals. In addition, the 3% Eu-doped sample exhibited very good adsorptive properties due to different morphology and higher electrostatic attraction with the anionic dye. Pr 1-x Eu x (OH) 3 nanostructures with the possibility of tuning their adsorption/photocatalytic properties present a great potential for wastewater treatment.

  9. Total OH reactivity measurements using a new fast Gas Chromatographic Photo-Ionization Detector (GC-PID

    Directory of Open Access Journals (Sweden)

    V. Sinha

    2012-12-01

    Full Text Available The primary and most important oxidant in the atmosphere is the hydroxyl radical (OH. Currently OH sinks, particularly gas phase reactions, are poorly constrained. One way to characterize the overall sink of OH is to measure directly the ambient loss rate of OH, the total OH reactivity. To date, direct measurements of total OH reactivity have been either performed using a Laser-Induced Fluorescence (LIF system ("pump-and-probe" or "flow reactor" or the Comparative Reactivity Method (CRM with a Proton-Transfer-Reaction Mass Spectrometer (PTR-MS. Both techniques require large, complex and expensive detection systems. This study presents a feasibility assessment for CRM total OH reactivity measurements using a new detector, a Gas Chromatographic Photoionization Detector (GC-PID. Such a system is smaller, more portable, less power consuming and less expensive than other total OH reactivity measurement techniques.

    Total OH reactivity is measured by the CRM using a competitive reaction between a reagent (here pyrrole with OH alone and in the presence of atmospheric reactive molecules. The new CRM method for total OH reactivity has been tested with parallel measurements of the GC-PID and the previously validated PTR-MS as detector for the reagent pyrrole during laboratory experiments, plant chamber and boreal field studies. Excellent agreement of both detectors was found when the GC-PID was operated under optimum conditions. Time resolution (60–70 s, sensitivity (LOD 3–6 s−1 and overall uncertainty (25% in optimum conditions for total OH reactivity were similar to PTR-MS based total OH reactivity measurements. One drawback of the GC-PID system was the steady loss of sensitivity and accuracy during intensive measurements lasting several weeks, and a possible toluene interference. Generally, the GC-PID system has been shown to produce closely comparable results to the PTR-MS and thus in suitable environments (e.g. forests it

  10. Tomographic reconstruction of OH* chemiluminescence in two interacting turbulent flames

    International Nuclear Information System (INIS)

    Worth, Nicholas A; Dawson, James R

    2013-01-01

    The tomographic reconstruction of OH* chemiluminescence was performed on two interacting turbulent premixed bluff-body stabilized flames under steady flow conditions and acoustic excitation. These measurements elucidate the complex three-dimensional (3D) vortex–flame interactions which have previously not been accessible. The experiment was performed using a single camera and intensifier, with multiple views acquired by repositioning the camera, permitting calculation of the mean and phase-averaged volumetric OH* distributions. The reconstructed flame structure and phase-averaged dynamics are compared with OH planar laser-induced fluorescence and flame surface density measurements for the first time. The volumetric data revealed that the large-scale vortex–flame structures formed along the shear layers of each flame collide when the two flames meet, resulting in complex 3D flame structures in between the two flames. With a fairly simple experimental setup, it is shown that the tomographic reconstruction of OH* chemiluminescence in forced flames is a powerful tool that can yield important physical insights into large-scale 3D flame dynamics that are important in combustion instability. (paper)

  11. Lahar inundated, modified, and preserved 1.88 Ma early hominin (OH24 and OH56) Olduvai DK site.

    Science.gov (United States)

    Stanistreet, I G; Stollhofen, H; Njau, J K; Farrugia, P; Pante, M C; Masao, F T; Albert, R M; Bamford, M K

    2018-03-01

    Archaeological excavations at the DK site in the eastern Olduvai Basin, Tanzania, age-bracketed between ∼1.88 Ma (Bed I Basalt) and ∼1.85 Ma (Tuff IB), record the oldest lahar inundation, modification, and preservation of a hominin "occupation" site yet identified. Our landscape approach reconstructs environments and processes at high resolution to explain the distribution and final preservation of archaeological materials at the DK site, where an early hominin (likely Homo habilis) assemblage of stone tools and bones, found close to hominin specimens OH24 and OH56, developed on an uneven heterogeneous surface that was rapidly inundated by a lahar and buried to a depth of 0.4-1.2 m (originally ∼1.0-2.4 m pre-compaction). The incoming intermediate to high viscosity mudflow selectively modified the original accumulation of "occupation debris," so that it is no longer confined to the original surface. A dispersive debris "halo" was identified within the lahar deposit: debris is densest immediately above the site, but tails off until not present >150 m laterally. Voorhies indices and metrics derived from limb bones are used to define this dispersive halo spatially and might indicate a possible second assemblage to the east that is now eroded away. Based upon our new data and prior descriptions, two possibilities for the OH24 skull are suggested: it was either entrained by the mudflow from the DK surface and floated due to lower density toward its top, or it was deposited upon the solid top surface after its consolidation. Matrix adhering to material found in association with the parietals indicates that OH56 at least was relocated by the mudflow. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. THE ZEEMAN EFFECT IN THE 44 GHZ CLASS I METHANOL MASER LINE TOWARD DR21(OH)

    Energy Technology Data Exchange (ETDEWEB)

    Momjian, E. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Sarma, A. P., E-mail: emomjian@nrao.edu, E-mail: asarma@depaul.edu [Physics Department, DePaul University, 2219 N. Kenmore Avenue, Byrne Hall 211, Chicago, IL 60614 (United States)

    2017-01-10

    We report detection of the Zeeman effect in the 44 GHz Class I methanol maser line, toward the star-forming region DR21(OH). In a 219 Jy beam{sup −1} maser centered at an LSR velocity of 0.83 km s{sup −1}, we find a 20- σ detection of zB {sub los} = 53.5 ± 2.7 Hz. If 44 GHz methanol masers are excited at n ∼ 10{sup 7–8} cm{sup −3}, then the B versus n {sup 1/2} relation would imply, from comparison with Zeeman effect detections in the CN(1 − 0) line toward DR21(OH), that magnetic fields traced by 44 GHz methanol masers in DR21(OH) should be ∼10 mG. Combined with our detected zB {sub los} = 53.5 Hz, this would imply that the value of the 44 GHz methanol Zeeman splitting factor z is ∼5 Hz mG{sup −1}. Such small values of z would not be a surprise, as the methanol molecule is non-paramagnetic, like H{sub 2}O. Empirical attempts to determine z , as demonstrated, are important because there currently are no laboratory measurements or theoretically calculated values of z for the 44 GHz CH{sub 3}OH transition. Data from observations of a larger number of sources are needed to make such empirical determinations robust.

  13. Breakdown of middle lamella pectin by (●) OH during rapid abscission in Azolla.

    Science.gov (United States)

    Yamada, Yoshiya; Koibuchi, Mizuki; Miyamoto, Kensuke; Ueda, Junichi; Uheda, Eiji

    2015-08-01

    Azolla, a small water fern, abscises its roots and branches within 30 min upon treatment with various stresses. This study was conducted to test whether, in the rapid abscission that occurs in Azolla, breakdown of wall components of abscission zone cells by (●) OH is involved. Experimentally generated (●) OH caused the rapid separation of abscission zone cells from detached roots and the rapid shedding of roots from whole plants. Electron microscopic observations revealed that (●) OH rapidly and selectively dissolved a well-developed middle lamella between abscission zone cells and resultantly caused rapid cell separation and shedding. Treatment of abscission zones of Impatiens leaf petiole with (●) OH also accelerated the separation of abscission zone cells. However, compared with that of Azolla roots, accelerative effects in Impatiens were weak. A large amount of (●) OH was cytochemically detected in abscission zone cells both of Azolla roots and of Impatiens leaf petioles. These results suggest that (●) OH is involved in the cell separation process not only in the rapid abscission in Azolla but also in the abscission of Impatiens. However, for rapid abscission to occur, a well-developed middle lamella, a unique structure, which is sensitive to the attack of (●) OH, might be needed. © 2015 John Wiley & Sons Ltd.

  14. Understanding LiOH chemistry in a ruthenium-catalyzed Li-O{sub 2} battery

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Tao; Liu, Zigeng; Kim, Gunwoo; Grey, Clare P. [Department of Chemistry, University of Cambridge (United Kingdom); Frith, James T.; Garcia-Araez, Nuria [Department of Chemistry, University of Southampton (United Kingdom)

    2017-12-11

    Non-aqueous Li-O{sub 2} batteries are promising for next-generation energy storage. New battery chemistries based on LiOH, rather than Li{sub 2}O{sub 2}, have been recently reported in systems with added water, one using a soluble additive LiI and the other using solid Ru catalysts. Here, the focus is on the mechanism of Ru-catalyzed LiOH chemistry. Using nuclear magnetic resonance, operando electrochemical pressure measurements, and mass spectrometry, it is shown that on discharging LiOH forms via a 4 e{sup -} oxygen reduction reaction, the H in LiOH coming solely from added H{sub 2}O and the O from both O{sub 2} and H{sub 2}O. On charging, quantitative LiOH oxidation occurs at 3.1 V, with O being trapped in a form of dimethyl sulfone in the electrolyte. Compared to Li{sub 2}O{sub 2}, LiOH formation over Ru incurs few side reactions, a critical advantage for developing a long-lived battery. An optimized metal-catalyst-electrolyte couple needs to be sought that aids LiOH oxidation and is stable towards attack by hydroxyl radicals. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Reactivity improvement of Ca(OH)2 sorbent using diatomaceous earth (DE) from Aceh Province

    Science.gov (United States)

    Mariana, M.; Mahidin, M.; Mulana, F.; Agam, T.; Hafdiansyah, F.

    2018-04-01

    In this study, the diatomaceous earth (DE) from Aceh Province was used to increase the reactivity of Ca(OH)2sorbent. The high silica (SiO2) content of about 97% in the diatomaceous earth allows the increasing reactivity of Ca(OH)2sorbent by forming calcium silicate hydrate (CSH). The CSH improved the porosity characteristic of the sorbent. The improvement process was performed by mixing Ca(OH)2sorbent, diatomaceous earth and water in a beaker glass at the Ca(OH)2/DE weight ratio of 1:10 for 2 hand then dried at 120 °C for 24 h. The dried sorbent was calcined at 500 °C and 800 °C for 2 h. The activated sorbent was characterized using Scanning Electron Microscopy (SEM) for the morphological properties; X- Ray Diffraction (XRD) for the materials characteristics. The adsorption capacity of thesorbent was tested by methylene blue adsorption. The results showed that the Ca(OH)2/DEsorbent had a higher porosity than the Ca(OH)2 adsorbent.The results also showed that Ca(OH)2/DE which was calcined at higher temperature of 800 °C had a higher adsorption capacity compared to Ca(OH)2/DE which was calcined at lower temperature of 500 °C.

  16. Oh oleksin ma rikas! : [luuletused] / Hans Christian Andersen ; tlk. Harald Rajamets

    Index Scriptorium Estoniae

    Andersen, Hans Christian, 1805-1875

    2004-01-01

    Sisu: Oh oleksin ma rikas! ; Tädi prillid ; "Oh vägev surm, sa külvad tummalt õudu..." ; "Meil maa peal elu kurblik näib..." ; "Kõik kaob nagu tuul siin ära..." ; "Lund on veel maas ja vahel teeb tuisku..."

  17. Mechanism and kinetic properties for the OH-initiated atmospheric oxidation degradation of 9,10-Dichlorophenanthrene.

    Science.gov (United States)

    Dang, Juan; Shi, Xiangli; Zhang, Qingzhu; Hu, Jingtian; Wang, Wenxing

    2015-02-01

    Chlorinated polycyclic aromatic hydrocarbons (ClPAHs) have become a serious environmental concern due to their widespread occurrence and dioxin-like toxicities. In this work, the mechanism of the OH-initiated atmospheric oxidation degradation of 9,10-dichlorophenanthrene (9,10-Cl₂Phe) was investigated by using high-accuracy quantum chemistry calculations. The rate constants of the crucial elementary reactions were determined by the Rice-Ramsperger-Kassel-Marcus (RRKM) theory. The theoretical results were compared with the available experimental data. The main oxidation products are a group of ring-retaining and ring-opening compounds including chlorophenanthrols, 9,10-dichlorophenanthrene-3,4-dione, dialdehydes, chlorophenanthrenequinones, nitro-9,10-Cl₂Phe and epoxides et al. The overall rate constant of the OH addition reaction is 2.35 × 10(-12)cm(3) molecule(-1)s(-1) at 298 K and 1 atm. The atmospheric lifetime of 9,10-Cl₂Phe determined by OH radicals is about 5.05 days. This study provides a comprehensive investigation of the OH-initiated oxidation degradation of 9,10-Cl₂Phe and should contribute to clarifying its atmospheric fate. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. An -OH group functionalized MOF for ratiometric Fe3+ sensing

    Science.gov (United States)

    Xu, Hui; Dong, Yingying; Wu, Yuhang; Ren, Wenjing; Zhao, Tao; Wang, Shunli; Gao, Junkuo

    2018-02-01

    Iron is one of the most important elements in the biochemical processes in all living system, both deficiency or excess of iron will lead to metabolism disorder diseases. However, Fe3+ is one of the most efficient fluorescence quenchers among the transition-metal ions because of its paramagnetic nature. The realization of Fe3+ ratiometric and self-calibrated fluorescent sensor is highly-challenging. We synthesized a novel luminescent -OH functionalized EuOHBDC (Eu2(OH-BDC)3, OH-BDC=2-hydroxyterephthalic acid) by hydrothermal reaction and in situ ligand synthesis, and used it as a rare ratiomatric luminescent sensor for Fe3+ ions. The -OH functional group facilitates both electron transfer and binding interaction between EuOHBDC and Fe3+, which lead to luminescent quenching of ligand-based emission while enhancement of a new peak emission, and thus enables ratiometric detection of Fe3+. The relative fluorescent intensity ratio (I375/I427) increased linearly with increasing Fe3+ concentration in the 10-50 μM range with 1.17 μM (65 ppb) detection limit. The EuOHBDC also shows excellent selectivity towards different metal ions, particularly can discriminate Fe3+ and Fe2+ through different luminescent responses. This result clearly demonstrates the superiority of -OH functionalized MOF for Fe3+ detection, which can contribute to develop high performance luminescent probe for detection of metal ions in environmental and biomedical applications.

  19. Characterization of midazolam metabolism in locusts: The role of CYP3A4-like enzyme in the formation of 1'-OH and 4-OH midazolam

    DEFF Research Database (Denmark)

    Olsen, Line Rørbæk; Gabel-Jensen, Charlotte; Wubshet, Sileshi Gizachew

    2016-01-01

    ) were in the same range as reported in humans (in locusts: 7-23 and 33-85 µM for the formation of the 1'-OH and 4-OH metabolites, respectively). 3. The formation of hydroxylated metabolites could successfully be inhibited by co-administration of ketoconazole, a known CYP3A4/5 inhibitor. 4. Besides phase...

  20. A dearth of OH/IR stars in the Small Magellanic Cloud

    Science.gov (United States)

    Goldman, Steven R.; van Loon, Jacco Th.; Gómez, José F.; Green, James A.; Zijlstra, Albert A.; Nanni, Ambra; Imai, Hiroshi; Whitelock, Patricia A.; Groenewegen, Martin A. T.; Oliveira, Joana M.

    2018-01-01

    We present the results of targeted observations and a survey of 1612-, 1665- and 1667-MHz circumstellar OH maser emission from asymptotic giant branch (AGB) stars and red supergiants (RSGs) in the Small Magellanic Cloud (SMC), using the Parkes and Australia Telescope Compact Array (ATCA) radio telescopes. No clear OH maser emission has been detected in any of our observations targeting luminous, long-period, large-amplitude variable stars, which have been confirmed spectroscopically and photometrically to be mid- to late-M spectral type. These observations have probed 3-4 times deeper than any OH maser survey in the SMC. Using a bootstrapping method with Large Magellanic Cloud (LMC) and Galactic OH/IR star samples and our SMC observation upper limits, we have calculated the likelihood of not detecting maser emission in any of the two sources considered to be the top maser candidates to be less than 0.05 per cent, assuming a similar pumping mechanism as the LMC and Galactic OH/IR sources. We have performed a population comparison of the Magellanic Clouds and used Spitzer IRAC and MIPS photometry to confirm that we have observed all high luminosity SMC sources that are expected to exhibit maser emission. We suspect that, compared to the OH/IR stars in the Galaxy and LMC, the reduction in metallicity may curtail the dusty wind phase at the end of the evolution of the most massive cool stars. We also suspect that the conditions in the circumstellar envelope change beyond a simple scaling of abundances and wind speed with metallicity.

  1. Charge selective contact on ultra-thin In(OH)xS y/Pb(OH) xS y heterostructure prepared by SILAR

    International Nuclear Information System (INIS)

    Gavrilov, S.; Oja, I.; Lim, B.; Belaidi, A.; Bohne, W.; Strub, E.; Roehrich, J.; Lux-Steiner, M.-Ch.; Dittrich, Th.

    2006-01-01

    Ultra-thin In(OH) x S y /Pb(OH) x S y heterostructures were formed by the wet chemical SILAR (successive ion layer adsorption and reaction) technique. ERDA (elastic recoil detection analysis) was used for stoichiometry analysis. The heterocontacts were conditioned by joint annealing of the two layers at different low temperatures in air. The charge selectivity was demonstrated with various small area solar cell structures. The results are discussed on the base of formation of bonds between sulphide clusters and passivation of defects with hydrogen containing species in hydroxy-sulphides. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Signatures of non-adiabatic dynamics in the fine-structure state distributions of the OH( X ˜ / A ˜ ) products in the B-band photodissociation of H2O

    Science.gov (United States)

    Zhou, Linsen; Xie, Daiqian; Guo, Hua

    2015-03-01

    A detailed quantum mechanical characterization of the photodissociation dynamics of H2O at 121.6 nm is presented. The calculations were performed using a full-dimensional wave packet method on coupled potential energy surfaces of all relevant electronic states. Our state-to-state model permits a detailed analysis of the OH( X ˜ / A ˜ ) product fine-structure populations as a probe of the non-adiabatic dissociation dynamics. The calculated rotational state distributions of the two Λ-doublet levels of OH( X ˜ , v = 0) exhibit very different characteristics. The A' states, produced mostly via the B ˜ → X ˜ conical intersection pathway, have significantly higher populations than the A″ counterparts, which are primarily from the B ˜ → A ˜ Renner-Teller pathway. The former features a highly inverted and oscillatory rotational state distribution, while the latter has a smooth distribution with much less rotational excitation. In good agreement with experiment, the calculated total OH( X ˜ ) rotational state distribution and anisotropy parameters show clear even-odd oscillations, which can be attributed to a quantum mechanical interference between waves emanating from the HOH and HHO conical intersections in the B ˜ → X ˜ non-adiabatic pathway. On the other hand, the experiment-theory agreement for the OH( A ˜ ) fragment is also satisfactory, although some small quantitative differences suggest remaining imperfections of the ab initio based potential energy surfaces.

  3. OH in the Tropical Upper Troposhere and Its Relationships to Solar Radiation and Reactive Nitrogen

    Science.gov (United States)

    Gao, R. S.; Rosenlof, K. H.; Fahey, D. W.; Wennberg, P. O.; Hintsa, E. J.; Hanisco, T. F.

    2014-01-01

    In situ measurements of [OH], [HO2] (square brackets denote species concentrations), and other chemical species were made in the tropical upper troposphere (TUT). [OH] showed a robust correlation with solar zenith angle. Beyond this dependence, however, [HOx] ([OH] + [HO2]) only weakly responds to variations in its source and sink species. For example, at a given SZA, [HOx] was broadly independent of the product of [O3] and [H2O]. This suggests that [OH] is heavily buffered in the TUT. One important exception to this result is found in regions with very low [O3], [NO], and [NOy], where [OH] is highly suppressed, pointing to the critical role of NO in sustaining OH in the TUT.

  4. Facile fabrication of flower like self-assembled mesoporous hierarchical microarchitectures of In(OH){sub 3} and In{sub 2}O{sub 3}: In(OH){sub 3} micro flowers with electron beam sensitive thin petals

    Energy Technology Data Exchange (ETDEWEB)

    Arul Prakasam, Balasubramaniam, E-mail: arul7777@yahoo.com [Laboratory of Green Chemistry, School of Engineering Science, Lappeenranta University of Technology, Sammonkatu 12, FI-50130, Mikkeli (Finland); Lahtinen, Manu; Peuronen, Anssi [Department of Chemistry, Laboratories of Inorganic and Analytical Chemistry, P.O. Box 35, FI-40014, University of Jyväskylä (Finland); Muruganandham, Manickavachagam [Department of Civil and Environmental Engineering, Temple University, Philadelphia, PA, 19122 (United States); Sillanpää, Mika [Laboratory of Green Chemistry, School of Engineering Science, Lappeenranta University of Technology, Sammonkatu 12, FI-50130, Mikkeli (Finland)

    2016-12-01

    A template and capping-reagent free facile fabrication method for mesoporous hierarchical microarchitectures of flower-like In(OH){sub 3} particles under benign hydrothermal conditions is reported. Calcination of In(OH){sub 3} to In{sub 2}O{sub 3} with the retention of morphology is also described. Both In(OH){sub 3} and In{sub 2}O{sub 3} microstructures were analyzed with SEM, EDX, TEM and powder X-ray diffraction. The crystal sizes for In(OH){sub 3} and In{sub 2}O{sub 3} were calculated using the Scherrer equation. In In(OH){sub 3} the thin flakes at the periphery of micro flowers were electron beam sensitive. The mechanism of self-assembly process was analyzed as well. - Highlights: • Hydrothermal fabrication In(OH){sub 3} self-assembled porous hierarchical architectures. • Induced dehydration in beam sensitive In(OH){sub 3} micro flowers. • Calcination of In(OH){sub 3} to In{sub 2}O{sub 3} with the retention of flower like morphology. • Phase pure synthesis of In{sub 2}O{sub 3} with the average crystal size of ∼37 nm.

  5. 41 CFR 105-1.102 - Relationship of GSPMR to FPMR.

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Relationship of GSPMR to FPMR. 105-1.102 Section 105-1.102 Public Contracts and Property Management Federal Property Management Regulations System (Continued) GENERAL SERVICES ADMINISTRATION 1-INTRODUCTION 1.1-Regulations System § 105-1...

  6. Simultaneous measurements of the OH(8,3) band and 015577A airglow emissions

    International Nuclear Information System (INIS)

    Takahashi, H.; Sahai, Y.; Clemesha, B.R.; Simonich, D.M.; Batista, P.P.; Teixeira, N.R.

    1981-01-01

    Simultaneous measurements of the night airglow OH(8,3) band and OI 5577A have been made at Cachoeira Paulista (22.7 0 S, 45,2 0 W) during June-August 1976. Correlations between the nocturnal variations of these emissions and also with the OH rotational temperature are presented. It is found that OH (8,3) is correlated with the rotational temperature but with a time lag of about 1 hour. The variations of 5577A lead the OH (8,3) by about 2 to 3 hours. The rotational temperature co-varies with 5577A, rather than OH (8,3) and there is no significant time lag. Based on the correlation study, the nocturnal variations of the two emissions can be explained by the atmospheric density perturbation caused by solar tides and internal gravity waves. (Author) [pt

  7. In vivo evaluation of the 3-carboranyl thymidine analogue (3-CTA), N5-2OH, for neutron capture therapy

    International Nuclear Information System (INIS)

    Barth, Rolf F.; Yang, Weilian; Wu, Gong; Byun, Youngjoo; Tjarks, Werner; Eriksson, Staffan; Binns, Peter J.; Riley, Kent J.

    2006-01-01

    The purpose of the present study was to evaluate a 3 CTA, designated N5-2OH, as a boron delivery agent for NCT. Target validation was established using the thymidine kinase 1 (+) wild type L929 cell line and its TK1(-) counterpart, which were implanted subcutaneously into NIH nu/nu mice. 10 B-enriched N5-2OH, solubilized in DMSO (50μg 10 B in 15μl), was administered by 2 intratumoral (i.t.) injections at 2 h intervals. Two hours later the animals were irradiated at the MITR-II Research Reactor, following which tumor volumes were determined over a period of 30 days. Mice bearing TK1(+) wild type tumors, which had received N5-2OH, had a 15 fold inhibition in tumor growth compared to TK1(-) controls (247 versus 3,603 mm 3 ). Based on these data, biodistribution and therapy studies were initiated in F98 glioma bearing rats. Animals received 500μg of N5-2OH, administered intracerebrally (i.c.) by convection enhanced delivery (CED) using ALZET pumps (8μl/h for 24 h). The tumor boron concentration was 17.3μg/g compared to undetectable amounts in normal brain and blood. BNCT was carried out 14 d following i.c. implantation of 10 3 F98 glioma cells and 24 h following CED of N5-2OH (500μg/200μl). The mean survival time (MST) of these animals was 38 d compared to 31 d and 25 d, respectively, for irradiated and untreated controls. Studies are planned to optimize the delivery and formulation of N5-2OH and additional therapy studies will be carried out using N5-2OH in combination with BPA and BSH. (author)

  8. OH Production Enhancement in Bubbling Pulsed Discharges

    Science.gov (United States)

    Lungu, Cristian P.; Porosnicu, Corneliu; Jepu, Ionut; Chiru, Petrica; Zaroschi, Valentin; Lungu, Ana M.; Saito, Nagahiro; Bratescu, Maria; Takai, Osamu; Velea, Theodor; Predica, Vasile

    2010-10-01

    The generation of active species, such as H2O2, O*, OH*, HO2*, O3, N2*, etc, produced in aqueous solutions by HV pulsed discharges was studied in order to find the most efficient way in waste water treatment taking into account that these species are almost stronger oxidizers than ozone. Plasma was generated inside gas bubbles formed by the argon, air and oxygen gas flow between the special designed electrodes. The pulse width and pulse frequency influence was studied in order to increase the efficiency of the OH active species formation. The produced active species were investigated by optical emission spectroscopy and correlated with electrical parameters of the discharges (frequency, pulse width, amplitude, and rise and decay time).

  9. OH Production Enhancement in Bubbling Pulsed Discharges

    International Nuclear Information System (INIS)

    Lungu, Cristian P.; Porosnicu, Corneliu; Jepu, Ionut; Chiru, Petrica; Zaroschi, Valentin; Lungu, Ana M.; Saito, Nagahiro; Bratescu, Maria; Takai, Osamu; Velea, Theodor; Predica, Vasile

    2010-01-01

    The generation of active species, such as H 2 O 2 , O * , OH*, HO 2 *, O 3 , N 2 * , etc, produced in aqueous solutions by HV pulsed discharges was studied in order to find the most efficient way in waste water treatment taking into account that these species are almost stronger oxidizers than ozone. Plasma was generated inside gas bubbles formed by the argon, air and oxygen gas flow between the special designed electrodes. The pulse width and pulse frequency influence was studied in order to increase the efficiency of the OH active species formation. The produced active species were investigated by optical emission spectroscopy and correlated with electrical parameters of the discharges (frequency, pulse width, amplitude, and rise and decay time).

  10. Experimental Study Of Precipitation Competition Of Ca(OH)2 And Mg(OH)2 On MSF Desalination Condition

    International Nuclear Information System (INIS)

    Sumijanto

    2001-01-01

    Competition study has been carried out by using sea water simulation containing of 142 on deposit ppm of bicarbonate ion, 400 ppm of calcium ion and 1272 ppm of magnesium ion. Experiment was performed by heating sample at temperature 50, 60, 70, 80, and 90 C for 30 minutes. Precipitation competition of Ca(OHh and Mg(OHh was analyzed by reduction of calcium and magnesium ion. Experiment data showed information that at the temperature bellow 800 o C CaCO 3 precipitation was more dominant, meanwhile above than 80 o C precipitation Mg(OH) 2 was more dominant. This competition occurred because at temperature more than 80 o C rate of hydroxyl ion formation and Mg(OH) 2 recipitation was greater than CaCO 3 precipitation and at temperature bellow 80 o C rate of hydrolysis carbonate ion was less than thermal decomposition bicarbonates ion

  11. Gas phase kinetics of the OH + CH3CH2OH reaction at temperatures of the interstellar medium (T = 21-10^7 K)

    Science.gov (United States)

    Ocaña, A. J.; Blázquez, S.; Ballesteros, B.; Canosa, A.; Antiñolo, M.; Albaladejoab, J.; Jiménez, E.

    2018-02-01

    Ethanol, CH3CH2OH, has been unveiled in the interstellar medium (ISM) by radioastronomy and it is thought to be released into the gas phase after the warm-up phase of the grain surface, where it is formed. Once in the gas phase, it can be destroyed by different reactions with atomic and radical species, such as hydroxyl (OH) radicals. The knowledge of the rate coefficients of all these processes at temperatures of the ISM is essential in the accurate interpretation of the observed abundances. In this work, we have determined the rate coefficient for the reaction of OH with CH3CH2OH (k(T)) between 21 and 10^7 K by employing the pulsed and continuous CRESU (Cinétique de Réaction en Ecoulement Supersonique Uniforme, which means Reaction Kinetics in a Uniform Supersonic Flow) technique. The pulsed laser photolysis technique was used for generating OH radicals, whose time evolution was monitored by laser induced fluorescence. An increase of approximately 4 times was observed for k(21 K) with respect to k(10^7 K). With respect to k(300 K), the OH-reactivity at 21 K is enhanced by two orders of magnitude. The obtained T-expression in the investigated temperature range is k(T) = (2.1 ± 0.5) × 10^-11 (T/300 K)-(0.71±0.10) cm^3 molecule^-1 s^-1. In addition, the pressure dependence of k(T) has been investigated at several temperatures between 21 K and 90 K. No pressure dependence of k(T) was observed in the investigated ranges. This may imply that this reaction is purely bimolecular or that the high-pressure limit is reached at the lowest total pressure experimentally accessible in our system. From our results, k(T) at usual IS temperatures (˜10-100 K) is confirmed to be very fast. Typical rate coefficients can be considered to range within about 4 × 10^-11 cm^3 molecule^-1 s^-1 at 100 K and around 1 × 10^-10 cm^3 molecule^-1 s^-1 at 20 K. The extrapolation of k at the lowest temperatures of the dense molecular clouds of ISM is also discussed in this paper.

  12. OH radicals distribution in an Ar-H{sub 2}O atmospheric plasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Li, L.; Leys, C. [Department of Applied Physics, Research Unit Plasma Technology, Ghent University, Sint-Pietersnieuwstraat 41, Ghent B-9000 (Belgium); Nikiforov, A. [Department of Applied Physics, Research Unit Plasma Technology, Ghent University, Sint-Pietersnieuwstraat 41, Ghent B-9000 (Belgium); Institute of Solution Chemistry of the Russian Academy of Sciences, Academicheskaya St., 1, Ivanono, 153045 (Russian Federation); Xiong, Q. [Department of Applied Physics, Research Unit Plasma Technology, Ghent University, Sint-Pietersnieuwstraat 41, Ghent B-9000 (Belgium); College of Electrical and Electronic Engineering, HuaZhong University of Science and Technology, WuHan, Hubei 430074 (China); Britun, N. [Chimie des Interactions Plasma-Surface (ChIPS), CIRMAP, Universite de Mons, 20 Place du Parc, B-7000 Mons (Belgium); Snyders, R. [Chimie des Interactions Plasma-Surface (ChIPS), CIRMAP, Universite de Mons, 20 Place du Parc, B-7000 Mons (Belgium); Materia Nova Research Centre, Parc Initialis, B-7000 Mons (Belgium); Lu, X. [College of Electrical and Electronic Engineering, HuaZhong University of Science and Technology, WuHan, Hubei 430074 (China)

    2013-09-15

    Recently, plasma jet systems found numerous applications in the field of biomedicine and treatment of temperature-sensitive materials. OH radicals are one of the main active species produced by these plasmas. Present study deals with the investigation of RF atmospheric pressure plasma jet in terms of OH radicals production by admixture of H{sub 2}O into argon used as a feed gas. Generation of OH radicals is studied by laser-induced fluorescence spectroscopy. The excitation dynamics of OH radicals induced by the laser photons is studied by time-resolved spectroscopy. It is shown that vibrational and rotational energy transfer processes, which are sensitive to the surrounding species, can lead to the complication in the OH radicals diagnostics at high pressure and have to be considered during experiments. The axial and radial 2D maps of absolute densities of hydroxyl radicals at different water contents are obtained. The highest density of 1.15 × 10{sup 20} m{sup −3} is measured in the plasma core for the case of 0.3% H{sub 2}O. In the x–y-plane, the OH density steeply decreases within a range of ±2 mm from its maximum value down to 10{sup 18} m{sup −3}. The effect of H{sub 2}O addition on the generation of OH radicals is investigated and discussed.

  13. Existence of a solid solution from brucite to β-Co(OH)2

    International Nuclear Information System (INIS)

    Giovannelli, F.; Delorme, F.; Autret-Lambert, C.; Seron, A.; Jean-Prost, V.

    2012-01-01

    Highlights: ► A solid solution exist between Mg(OH) 2 and β-Co(OH) 2 . ► Synthesis has been performed through an easy and fast coprecipitation route. ► No long range-ordering of the cations occurs. -- Abstract: This study shows that between brucite (Mg(OH) 2 ) and β-Co(OH) 2 , all the compositions are possible. The solid solution Mg 1−x Co x (OH) 2 has been synthesized by an easy and fast coprecipitation route and characterized by XRD and TEM. Single phase powders have been obtained. The particles exhibit platelets morphology with a size close to one hundred nanometers. XRD analysis shows an evolution of the cell parameters when x increases and demonstrates that no ordering of the cations occurs. However, extra reflections on TEM electron diffraction patterns seem to indicate that local ordering can exist. The compounds issued from this solid solution could be good candidates as precursors in order to obtain Mg–Co mixed oxide with all possible cationic ratios.

  14. Redetermination of Ce[B5O8(OH(H2O]NO3·2H2O

    Directory of Open Access Journals (Sweden)

    Ya-Xi Huang

    2012-05-01

    Full Text Available The crystal structure of Ce[B5O8(OH(H2O]NO3·2H2O, cerium(III aquahydroxidooctaoxidopentaborate nitrate dihydrate, has been redetermined from single-crystal X-ray diffraction data. In contrast to the previous determination [Li et al. (2003. Chem. Mater. 15, 2253–2260], the present study reveals the location of all H atoms, slightly different fundamental building blocks (FBBs of the polyborate anions, more reasonable displacement ellipsoids for all non-H atoms, as well as a model without disorder of the nitrate anion. The crystal structure is built from corrugated polyborate layers parallel to (010. These layers, consisting of [B5O8(OH(H2O]2− anions as FBBs, stack along [010] and are linked by Ce3+ ions, which exhibit a distorted CeO10 coordination sphere. The layers are additionally stabilized via O—H...O hydrogen bonds between water molecules and nitrate anions, located at the interlayer space. The [BO3(H2O]-group shows a [3 + 1] coordination and is considerably distorted from a tetrahedral configuration. Bond-valence-sum calculation shows that the valence sum of boron is only 2.63 valence units (v.u. when the contribution of the water molecule (0.49 v.u. is neglected.

  15. CuSn(OH)6 submicrospheres: Room-temperature synthesis, growth mechanism, and weak antiferromagnetic behavior

    International Nuclear Information System (INIS)

    Zhong, Sheng-Liang; Xu, Rong; Wang, Lei; Li, Yuan; Zhang, Lin-Fei

    2011-01-01

    Highlights: ► CuSn(OH) 6 spheres have been synthesized via an aqueous solution method at room temperature. ► The diameters of the CuSn(OH) 6 spheres can be tuned by adjusting the molar ratio of SnO 3 2− to Cu 2+ . ► The as-obtained CuSn(OH) 6 spheres are antiferromagnetic and have a weak spin-Peierls transition at about 78 K -- Abstract: CuSn(OH) 6 submicrospheres with diameters of 400–900 nm have been successfully fabricated using a simple aqueous solution method at room temperature. Influencing factors such as the dosage of reactants and reaction time on the preparation were systematically investigated. The products were characterized with X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TG) and differential thermal analysis (DTA). Results reveal that the CuSn(OH) 6 spheres are built from numerous nanoparticles. It is found that the diameter of CuSn(OH) 6 spheres can be readily tuned by adjusting the molar ratio of SnO 3 2− to Cu 2+ . A possible growth mechanism for the CuSn(OH) 6 submicrospheres has been proposed. Amorphous CuSnO 3 submicrospheres were obtained after thermal treatment of the CuSn(OH) 6 submicrospheres at 300 °C for 4 h. Standard magnetization measurements demonstrate that the CuSn(OH) 6 submicrospheres are antiferromagnetic and have a weak spin-Peierls transition at about 78 K.

  16. ACCURATE OH MASER POSITIONS FROM THE SPLASH PILOT REGION

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, Hai-Hua; Shen, Zhi-Qiang [Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai, 200030 (China); Walsh, Andrew J.; Jordan, Christopher H. [International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth WA 6845 (Australia); Green, James A. [CSIRO Astronomy and Space Science, Australia Telescope National Facility, PO Box 76, Epping, NSW 2121 (Australia); Breen, Shari L. [Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006 (Australia); Dawson, J. R. [Department of Physics and Astronomy and MQ Research Centre in Astronomy, Astrophysics and Astrophotonics, Macquarie University, NSW 2109 (Australia); Ellingsen, Simon P. [School of Physical Sciences, Private Bag 37,University of Tasmania, Hobart 7001, TAS (Australia); Gómez, José F. [Instituto de Astrofísica de Andalucía, CSIC, Glorieta de la Astronomía s/n, E-18008, Granada (Spain); Lowe, Vicki; Jones, Paul A., E-mail: qiaohh@shao.ac.cn [Department of Astrophysics and Optic, School of Physics, University of New South Wales, Sydney, NSW 2052 (Australia)

    2016-12-01

    We report on high spatial resolution observations, using the Australia Telescope Compact Array (ATCA), of ground-state OH masers. These observations were carried out toward 196 pointing centers previously identified in the Southern Parkes Large-Area Survey in Hydroxyl (SPLASH) pilot region, between Galactic longitudes of 334° and 344° and Galactic latitudes of −2° and +2°. Supplementing our data with data from the MAGMO (Mapping the Galactic Magnetic field through OH masers) survey, we find maser emission toward 175 of the 196 target fields. We conclude that about half of the 21 nondetections were due to intrinsic variability. Due to the superior sensitivity of the followup ATCA observations, and the ability to resolve nearby sources into separate sites, we have identified 215 OH maser sites toward the 175 fields with detections. Among these 215 OH maser sites, 111 are new detections. After comparing the positions of these 215 maser sites to the literature, we identify 122 (57%) sites associated with evolved stars (one of which is a planetary nebula), 64 (30%) with star formation, two sites with supernova remnants, and 27 (13%) of unknown origin. The infrared colors of evolved star sites with symmetric maser profiles tend to be redder than those of evolved star sites with asymmetric maser profiles, which may indicate that symmetric sources are generally at an earlier evolutionary stage.

  17. Activation of Ca(OH){sub 2} using different siliceous materials

    Energy Technology Data Exchange (ETDEWEB)

    Karatepe, N.; Ersoy-Mericboyu, A.; Kucukbayrak, S. [Istanbul Technical University, Istanbul (Turkey)

    1999-04-01

    Siliceous materials such as silica fume, bentonite and diatomite were mixed with Ca(OH){sub 2} and hydrated at different conditions to produce reactive SO{sub 2} sorbents. Two different hydration methods were used, namely atmospheric and pressure hydration. The effects of the hydration temperature, time and siliceous material/Ca(OH){sub 2} weight ratio on the physical properties of the activated sorbents wereinvestigated. A statistical design technique was applied by use of a two-level factorial design matrix to interpret experimental results. In atmospheric hydration, it was found that increasing the temperature and hydration time caused an increase in the total surface area of the sorbents. But, increasing the siliceous material/Ca(OH){sub 2} weight ratio caused a decrease in the total surface area of the sorbents. In pressure hydration, mathematical analysis showed that the surface area of the activated sorbents was positively affected by the hydration variables. Thermogravimetric measurements showed that increasing the amount of reacted Ca(OH){sub 2} during hydration caused an increase in the surface area of the sorbent. X-ray diffraction studies also indicated that calcium silicate hydrates were the principal Ca-containing species formed during hydration.

  18. Serum 25(OH)D and incident type 2 diabetes

    DEFF Research Database (Denmark)

    Husemoen, L L N; Skaaby, T; Thuesen, B H

    2012-01-01

    Mild to moderate vitamin D insufficiency has been proposed as a risk factor for several common chronic diseases including type 2 diabetes. This study aimed to examine the association between serum 25-hydroxy vitamin D (25(OH)D) and incident diabetes.......Mild to moderate vitamin D insufficiency has been proposed as a risk factor for several common chronic diseases including type 2 diabetes. This study aimed to examine the association between serum 25-hydroxy vitamin D (25(OH)D) and incident diabetes....

  19. The relationships between OHS prevention costs, safety performance, employee satisfaction and accident costs.

    Science.gov (United States)

    Bayram, Metin; Ünğan, Mustafa C; Ardıç, Kadir

    2017-06-01

    Little is known about the costs of safety. A literature review conducted for this study indicates there is a lack of survey-based research dealing with the effects of occupational health and safety (OHS) prevention costs. To close this gap in the literature, this study investigates the interwoven relationships between OHS prevention costs, employee satisfaction, OHS performance and accident costs. Data were collected from 159 OHS management system 18001-certified firms operating in Turkey and analyzed through structural equation modeling. The findings indicate that OHS prevention costs have a significant positive effect on safety performance, employee satisfaction and accident costs savings; employee satisfaction has a significant positive effect on accident costs savings; and occupational safety performance has a significant positive effect on employee satisfaction and accident costs savings. Also, the results indicate that safety performance and employee satisfaction leverage the relationship between prevention costs and accident costs.

  20. Carbon-14 immobilization via the CO2-Ba(OH)2 hydrate gas-solid reaction

    International Nuclear Information System (INIS)

    Haag, G.L.

    1981-08-01

    For the treatment of an air-based off-gas stream, the use of packed beds of Ba(OH) 2 .8H 2 O flakes to remove CO 2 has been demonstrated. However, the operating conditions must be maintained between certain upper and lower limits with respect to the partial pressure of water. If the water vapor pressure in the gas is less than the dissociation vapor pressure of Ba(OH) 2 .8H 2 O, the bed will deactivate. If the vapor pressure is considerably greater, pressure drop problems will increase with increaseing humidity as the particles curl and degrade. Results have indicted that when operated in the proper regime, the bulk of the increase in pressure drop results from the conversion of Ba(OH) 2 .8H 2 O to BaCO 3 and not from the hydration of the commercial Ba(OH) 2 .8H 2 O (i.e., Ba(OH) 2 .7.50H 2 O) to Ba(OH) 2 .8H 2 O

  1. Formation of Lanthanum Hydroxide nano structures: Effect of NaOH and KOH solvents

    International Nuclear Information System (INIS)

    Mazloumi, M.; Zanganeh, S.; Kajbafvala, A.; Shayegh, M. R.; Sadrnezhaad, S. K.

    2008-01-01

    Lanthanum hydroxide (La(OH) 3 ) nano structures, including elliptical nanoparticles, octahedral rods and irregular nanoparticles were prepared chemically in NaOH and KOH solutions with 10 M concentration. The obtained powders were characterized with x-ray diffraction, scanning electron microscopy, transmission electron microscopy and differential thermal analysis. Crystallinities, morphologies and thermal behavior of the obtained nano structure powders were investigated under the influence of above mentioned solvents. The effect of chemical's temperature was also determined in one of the solvents (i.e. NaOH). The formation of growth in nano structure mechanism under the influence of alkali solutions (i.e., KOH and NaOH) have been discussed considerably in this paper

  2. Operating power plant experience with condensate polishing units in morpholine/ammonia-OH cycle

    International Nuclear Information System (INIS)

    Kumbhar, A.G.; Padmakumari, T.V.; Narasimhan, S.V.; Mathur, P.K.

    1995-01-01

    Impurity removal efficiency of condensate polisher plant (CPP) in ammonium cycle is poor. Cost considerations demand CPP operation in amine-OH cycle. With certain precautions such as higher regeneration levels, good regenerent quality, minimized cross contamination, continuous monitoring of influent and effluent and provision for 100% standby bed, it is possible to operate CPP beyond H-OH cycle while keeping the effluent impurities within the specified limits. This paper presents problem associated with the Madras Atomic Power Station (MAPS) CPP operation in morpholine-OH form and Korba Super Thermal Power Station (KSTPS) CPP in ammonia-OH form and suggested remedial measures. (author). 3 refs., 1 fig

  3. Optimization of NaOH Molarity, LUSI Mud/Alkaline Activator, and Na2SiO3/NaOH Ratio to Produce Lightweight Aggregate-Based Geopolymer

    Directory of Open Access Journals (Sweden)

    Rafiza Abdul Razak

    2015-05-01

    Full Text Available This paper presents the mechanical function and characterization of an artificial lightweight geopolymer aggregate (ALGA using LUSI (Sidoarjo mud and alkaline activator as source materials. LUSI stands for LU-Lumpur and SI-Sidoarjo, meaning mud from Sidoarjo which erupted near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia on 27 May 2006. The effect of NaOH molarity, LUSI mud/Alkaline activator (LM/AA ratio, and Na2SiO3/NaOH ratio to the ALGA are investigated at a sintering temperature of 950 °C. The results show that the optimum NaOH molarity found in this study is 12 M due to the highest strength (lowest AIV value of 15.79% with lower water absorption and specific gravity. The optimum LUSI mud/Alkaline activator (LM/AA ratio of 1.7 and the Na2SiO3/NaOH ratio of 0.4 gives the highest strength with AIV value of 15.42% with specific gravity of 1.10 g/cm3 and water absorption of 4.7%. The major synthesized crystalline phases were identified as sodalite, quartz and albite. Scanning Electron Microscope (SEM image showed more complete geopolymer matrix which contributes to highest strength of ALGA produced.

  4. Optimization of NaOH Molarity, LUSI Mud/Alkaline Activator, and Na2SiO3/NaOH Ratio to Produce Lightweight Aggregate-Based Geopolymer

    Science.gov (United States)

    Abdul Razak, Rafiza; Abdullah, Mohd Mustafa Al Bakri; Hussin, Kamarudin; Ismail, Khairul Nizar; Hardjito, Djwantoro; Yahya, Zarina

    2015-01-01

    This paper presents the mechanical function and characterization of an artificial lightweight geopolymer aggregate (ALGA) using LUSI (Sidoarjo mud) and alkaline activator as source materials. LUSI stands for LU-Lumpur and SI-Sidoarjo, meaning mud from Sidoarjo which erupted near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia on 27 May 2006. The effect of NaOH molarity, LUSI mud/Alkaline activator (LM/AA) ratio, and Na2SiO3/NaOH ratio to the ALGA are investigated at a sintering temperature of 950 °C. The results show that the optimum NaOH molarity found in this study is 12 M due to the highest strength (lowest AIV value) of 15.79% with lower water absorption and specific gravity. The optimum LUSI mud/Alkaline activator (LM/AA) ratio of 1.7 and the Na2SiO3/NaOH ratio of 0.4 gives the highest strength with AIV value of 15.42% with specific gravity of 1.10 g/cm3 and water absorption of 4.7%. The major synthesized crystalline phases were identified as sodalite, quartz and albite. Scanning Electron Microscope (SEM) image showed more complete geopolymer matrix which contributes to highest strength of ALGA produced. PMID:26006238

  5. All Fiber-Coupled OH Planar Laser-Induced-Fluorescence (OH-PLIF)-Based Two-Dimensional Thermometry.

    Science.gov (United States)

    Hsu, Paul S; Jiang, Naibo; Patnaik, Anil K; Katta, Vish; Roy, Sukesh; Gord, James R

    2018-04-01

    Two-color, planar laser-induced fluorescence (PLIF)-based two-dimensional (2D) thermometry techniques for reacting flows, which are typically developed in the laboratory conditions, face a stiff challenge in their practical implementation in harsh environments such as combustion rigs. In addition to limited optical access, the critical experimental conditions (i.e., uncontrolled humidity, vibration, and large thermal gradients) often restrict sensitive laser system operation and cause difficulties maintaining beam-overlap. Thus, an all fiber-coupled, two-color OH-PLIF system has been developed, employing two long optical fibers allowing isolation of the laser and signal-collection systems. Two OH-excitation laser beams (∼283 nm and ∼286 nm) are delivered through a common 6 m long, 400 µm core, deep ultraviolet (UV)-enhanced multimode fiber. The fluorescence signal (∼310 nm) is collected by a 3 m long, UV-grade imaging fiber. Proof-of-principle temperature measurements are demonstrated in atmospheric pressure, near adiabatic, CH 4 /O 2 /N 2 jet flames. The effects of the excitation pulse interval on fiber transmission are investigated. The proof-of-principle measurements show significant promise for thermometry in harsh environments such as gas turbine engine tests.

  6. Quantification of Hydroxylated Polybrominated Diphenyl Ethers (OH-BDEs), Triclosan, and Related Compounds in Freshwater and Coastal Systems.

    Science.gov (United States)

    Kerrigan, Jill F; Engstrom, Daniel R; Yee, Donald; Sueper, Charles; Erickson, Paul R; Grandbois, Matthew; McNeill, Kristopher; Arnold, William A

    2015-01-01

    Hydroxylated polybrominated diphenyl ethers (OH-BDEs) are a new class of contaminants of emerging concern, but the relative roles of natural and anthropogenic sources remain uncertain. Polybrominated diphenyl ethers (PBDEs) are used as brominated flame retardants, and they are a potential source of OH-BDEs via oxidative transformations. OH-BDEs are also natural products in marine systems. In this study, OH-BDEs were measured in water and sediment of freshwater and coastal systems along with the anthropogenic wastewater-marker compound triclosan and its photoproduct dioxin, 2,8-dichlorodibenzo-p-dioxin. The 6-OH-BDE 47 congener and its brominated dioxin (1,3,7-tribromodibenzo-p-dioxin) photoproduct were the only OH-BDE and brominated dioxin detected in surface sediments from San Francisco Bay, the anthropogenically impacted coastal site, where levels increased along a north-south gradient. Triclosan, 6-OH-BDE 47, 6-OH-BDE 90, 6-OH-BDE 99, and (only once) 6'-OH-BDE 100 were detected in two sediment cores from San Francisco Bay. The occurrence of 6-OH-BDE 47 and 1,3,7-tribromodibenzo-p-dioxin sediments in Point Reyes National Seashore, a marine system with limited anthropogenic impact, was generally lower than in San Francisco Bay surface sediments. OH-BDEs were not detected in freshwater lakes. The spatial and temporal trends of triclosan, 2,8-dichlorodibenzo-p-dioxin, OH-BDEs, and brominated dioxins observed in this study suggest that the dominant source of OH-BDEs in these systems is likely natural production, but their occurrence may be enhanced in San Francisco Bay by anthropogenic activities.

  7. Quantification of Hydroxylated Polybrominated Diphenyl Ethers (OH-BDEs, Triclosan, and Related Compounds in Freshwater and Coastal Systems.

    Directory of Open Access Journals (Sweden)

    Jill F Kerrigan

    Full Text Available Hydroxylated polybrominated diphenyl ethers (OH-BDEs are a new class of contaminants of emerging concern, but the relative roles of natural and anthropogenic sources remain uncertain. Polybrominated diphenyl ethers (PBDEs are used as brominated flame retardants, and they are a potential source of OH-BDEs via oxidative transformations. OH-BDEs are also natural products in marine systems. In this study, OH-BDEs were measured in water and sediment of freshwater and coastal systems along with the anthropogenic wastewater-marker compound triclosan and its photoproduct dioxin, 2,8-dichlorodibenzo-p-dioxin. The 6-OH-BDE 47 congener and its brominated dioxin (1,3,7-tribromodibenzo-p-dioxin photoproduct were the only OH-BDE and brominated dioxin detected in surface sediments from San Francisco Bay, the anthropogenically impacted coastal site, where levels increased along a north-south gradient. Triclosan, 6-OH-BDE 47, 6-OH-BDE 90, 6-OH-BDE 99, and (only once 6'-OH-BDE 100 were detected in two sediment cores from San Francisco Bay. The occurrence of 6-OH-BDE 47 and 1,3,7-tribromodibenzo-p-dioxin sediments in Point Reyes National Seashore, a marine system with limited anthropogenic impact, was generally lower than in San Francisco Bay surface sediments. OH-BDEs were not detected in freshwater lakes. The spatial and temporal trends of triclosan, 2,8-dichlorodibenzo-p-dioxin, OH-BDEs, and brominated dioxins observed in this study suggest that the dominant source of OH-BDEs in these systems is likely natural production, but their occurrence may be enhanced in San Francisco Bay by anthropogenic activities.

  8. The Far Infrared Lines of OH as Molecular Cloud Diagnostics

    Science.gov (United States)

    Smith, Howard A.

    2004-01-01

    Future IR missions should give some priority to high resolution spectroscopic observations of the set of far-IR transitions of OH. There are 15 far-IR lines arising between the lowest eight rotational levels of OH, and ISO detected nine of them. Furthermore, ISO found the OH lines, sometimes in emission and sometimes in absorption, in a wide variety of galactic and extragalactic objects ranging from AGB stars to molecular clouds to active galactic nuclei and ultra-luminous IR galaxies. The ISO/LWS Fabry-Perot resolved the 119 m doublet line in a few of the strong sources. This set of OH lines provides a uniquely important diagnostic for many reasons: the lines span a wide wavelength range (28.9 m to 163.2 m); the transitions have fast radiative rates; the abundance of the species is relatively high; the IR continuum plays an important role as a pump; the contribution from shocks is relatively minor; and, not least, the powerful centimeter-wave radiation from OH allows comparison with radio and VLBI datasets. The problem is that the large number of sensitive free parameters, and the large optical depths of the strongest lines, make modeling the full set a difficult job. The SWAS montecarlo radiative transfer code has been used to analyze the ISO/LWS spectra of a number of objects with good success, including in both the lines and the FIR continuum; the DUSTY radiative transfer code was used to insure a self-consistent continuum. Other far IR lines including those from H2O, CO, and [OI] are also in the code. The OH lines all show features which future FIR spectrometers should be able to resolve, and which will enable further refinements in the details of each cloud's structure. Some examples are given, including the case of S140, for which independent SWAS data found evidence for bulk flows.

  9. Atmospheric reactions of methylcyclohexanes with Cl atoms and OH radicals: determination of rate coefficients and degradation products.

    Science.gov (United States)

    Ballesteros, Bernabé; Ceacero-Vega, Antonio A; Jiménez, Elena; Albaladejo, José

    2015-04-01

    mechanism for ring-retaining product channels is proposed to justify the observed reaction products. The global tropospheric lifetimes estimated from the reported OH- and Cl-rate coefficients show that the main removal path for the investigated methylcyclohexanes is the reaction with OH radicals. But in marine environments, after sunrise, Cl reactions become more important in the tropospheric degradation. Thus, the estimated lifetimes range from 16 to 24 h for the reactions of the OH radical (calculated with [OH] = 10(6) atoms cm(-3)) and around 7-8 h in the reactions with Cl atoms in marine environments (calculated with [Cl] = 1.3 × 10(5) atoms cm(-3)). The reaction of Cl atoms and OH radicals and methylcylohexanes can proceed by H abstraction from the different positions.

  10. Monitoring OH-PCBs in PCB transport worker's urine as a non-invasive exposure assessment tool.

    Science.gov (United States)

    Haga, Yuki; Suzuki, Motoharu; Matsumura, Chisato; Okuno, Toshihiro; Tsurukawa, Masahiro; Fujimori, Kazuo; Kannan, Narayanan; Weber, Roland; Nakano, Takeshi

    2018-04-14

    In this study, we analyzed hydroxylated polychlorinated biphenyls (OH-PCBs) in urine of both PCB transport workers and PCB researchers. A method to monitor OH-PCB in urine was developed. Urine was solid-phase extracted with 0.1% ammonia/ methanol (v/v) and glucuronic acid/sulfate conjugates and then decomposed using β-glucuronidase/arylsulfatase. After alkaline digestion/derivatization, the concentration of OH-PCBs was determined by HRGC/HRMS-SIM. In the first sampling campaign, the worker's OH-PCB levels increased several fold after the PCB waste transportation work, indicating exposure to PCBs. The concentration of OH-PCBs in PCB transport workers' urine (0.55~11 μg/g creatinine (Cre)) was higher than in PCB researchers' urine (PCB storage area. In the second sampling, after recommended PCB exposure reduction measures had been enacted, the worker's PCB levels did not increase during handling of PCB equipment. This suggests that applied safety measures improved the situation. Hydroxylated trichlorobiphenyls (OH-TrCBs) were identified as a major homolog of OH-PCBs in urine. Also, hydroxylated tetrachlorobiphenyls (OH-TeCBs) to hydroxylated hexachlorobiphenyls (OH-HxCBs) were detected. For the sum of ten selected major indicators, a strong correlation to total OH-PCBs were found and these can possibly be used as non-invasive biomarkers of PCB exposure in workers managing PCB capacitors and transformer oils. We suggest that monitoring of OH-PCBs in PCB management projects could be considered a non-invasive way to detect exposure. It could also be used as a tool to assess and improve PCB management. This is highly relevant considering the fact that in the next 10 years, approx. 14 million tons of PCB waste need to be managed. Also, the selected populations could be screened to assess whether exposure at work, school, or home has taken place.

  11. Graphite oxide/β-Ni(OH)2 composites for application in supercapacitors

    Science.gov (United States)

    Singh, Arvinder; Chandra, Amreesh

    2013-06-01

    Graphite oxide/β-Ni(OH)2 composites have been investigated as electrode material in supercapacitors. Phase formation of electrode material is investigated using diffraction measurements. Particle shape-size studies show deposition of β-Ni(OH)2 nanoparticles on graphite oxide (GO) sheets. Electrochemical performance of GO/β-Ni(OH)2 composite in supercapacitors is discussed based on the analysis of electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and galvanostatic charge-discharge studies. Excellent energy density of ˜53 Wh/kg in 1M Na2SO4 aqueous electrolyte is reported at power density of ˜1364W/kg. The significance of results is discussed in the paper.

  12. Impact of OH Heterogenous Oxidation on the Evolution of Brown Carbon Aerosol Optical Properties

    Science.gov (United States)

    Schnitzler, E.; Abbatt, J.

    2017-12-01

    The effects of varying relative humidity (RH) on the evolution of brown carbon (BrC) optical properties induced by heterogeneous OH oxidation were investigated in a series of photooxidation chamber experiments. A BrC surrogate was generated from aqueous 1,3-dihydroxybenzene (10 mM) and H2O2 (10 mM) exposed to >300 nm radiation, atomized, passed through a series of trace gas denuders, and injected into the chamber, which was conditioned to about 10 or 60% RH. Following aerosol injection, H2O2 was continuously bubbled into the chamber; an hour later, the chamber was irradiated with black-lights (UV-B) to produce OH. Before irradiation, aerosol absorption and scattering at 405 nm, measured using a photoacoustic spectrometer, decreased due only to deposition and dilution, and single scattering albedo (SSA) was relatively steady. In the presence of gas-phase OH, absorption first increased, despite continued particle losses, and SSA decreased. Subsequently, absorption decreased faster than scattering, and SSA increased uniformly. At 60% RH, colour enhancement, likely associated with functionalization, was greatest after only minutes of reaction. In contrast, at 10% RH, peak colour enhancement occurred after about two hours of reaction, indicating that the decrease in RH and the attendant increase in particle viscosity significantly impeded heterogeneous OH oxidation of the BrC surrogate.

  13. New check-in desks in an airport: The OHS consultant as a 'political reflective navigator'

    DEFF Research Database (Denmark)

    Broberg, Ole; Hermund, Ingelise

    2003-01-01

    The occupational health service (OHS) in Denmark is only sparsely involved as adviser when technologi-cal changes take place in client enterprises. In order to promote the OHS efforts in this area, the work practise of OHS consultants has been studied in four cases of technological change....... Traditionally the role of OHS consultants is placed on a line between an expert and a process consultant. Based on evidence from the cases and concepts from actor-network theory on technological development, we suggest a sup-plementary third role, the ‘political reflective navigator’. In this role the OHS...

  14. Assay of 25-OH vitamin D3

    International Nuclear Information System (INIS)

    Nayer, P. de; Thalasso, M.; Beckers, C.

    1977-01-01

    A simplified version of the competitive protein binding assay for 25-OH vit D3 derived from the method of Belsey et al. is presented. The procedure does not include a chromatography step, and is performed on an alcoolic extract of 0.1 ml plasma or serum. Normal rat serum (1:20,000) was used as binding protein. No β-lipoproteins were added to the assay buffer. A 10% displacement of the tracer was observed at 0.04 ng/tube, and 50% at 0.15 ng/tube, allowing for the measurement of 25-OH vit D3 concentrations between 2 ng/ml and 200 ng/ml. Mean values in a normal group was 23.1 +- 6.5 ng/ml (range 16-37 ng/ml, n = 11). (orig.) [de

  15. Investigation of the C-3-epi-25(OH)D3 of 25-hydroxyvitamin D3 in urban schoolchildren.

    Science.gov (United States)

    Berger, Samantha E; Van Rompay, Maria I; Gordon, Catherine M; Goodman, Elizabeth; Eliasziw, Misha; Holick, Michael F; Sacheck, Jennifer M

    2018-03-01

    The physiological relevance C-3 epimer of 25-hydroxyvitamin D (3-epi-25(OH)D) is not well understood among youth. The objective of this study was to assess whether demographic/physiologic characteristics were associated with 3-epi-25(OH)D 3 concentrations in youth. Associations between 3-epi-25(OH)D 3 and demographics and between 3-epi-25(OH)D 3 , total 25-hydroxyvitamin (25(OH)D) (25(OH)D 2 + 25(OH)D 3 ), total cholesterol, high-density lipoprotein, low-density lipoprotein, and triglycerides were examined in racially/ethnically diverse schoolchildren (n = 682; age, 8-15 years) at Boston-area urban schools. Approximately 50% of participants had detectable 3-epi-25(OH)D 3 (range 0.95-3.95 ng/mL). The percentage of 3-epi-25(OH)D 3 of total 25(OH)D ranged from 2.5% to 17.0% (median 5.5%). Males were 38% more likely than females to have detectable 3-epi-25(OH)D 3 concentrations. Both Asian and black race/ethnicity were associated with lower odds of having detectable 3-epi-25(OH)D 3 compared with non-Hispanic white children (Asian vs. white, odds ratio (OR) 0.28, 95% confidence interval (CI) 0.14-0.53; black vs. white, OR 0.38, 95%CI 0.23-0.63, p 30 ng/mL) 25(OH)D concentration was associated with higher odds of having detectable 3-epi-25(OH)D 3 than having an inadequate (<20 ng/mL) concentration (OR 4.78, 95%CI 3.23-6.94 or OR 14.10, 95%CI 7.10-28.0, respectively). There was no association between 3-epi-25(OH)D 3 and blood lipids. However, when considering 3-epi-25(OH)D 3 as a percentage of total 25(OH)D, total cholesterol was lower in children with percent 3-epi-25(OH)D 3 above the median (mean difference -7.1 mg/dL, p = 0.01). In conclusion, among schoolchildren, sex, race/ethnicity, and total serum 25(OH)D concentration is differentially associated with 3-epi-25(OH)D. The physiological relevance of 3-epi-25(OH)D 3 may be related to the 3-epi-25(OH)D 3 as a percentage of total 25(OH)D and should be considered in future investigations.

  16. Rate Coefficients of the Reaction of OH with Allene and Propyne at High Temperatures

    KAUST Repository

    Es-sebbar, Et-touhami

    2016-09-28

    Allene (H2C═C═CH2; a-C3H4) and propyne (CH3C≡CH; p-C3H4) are important species in various chemical environments. In combustion processes, the reactions of hydroxyl radicals with a-C3H4 and p-C3H4 are critical in the overall fuel oxidation system. In this work, rate coefficients of OH radicals with allene (OH + H2C═C═CH2 → products) and propyne (OH + CH3C≡CH → products) were measured behind reflected shock waves over the temperature range of 843–1352 K and pressures near 1.5 atm. Hydroxyl radicals were generated by rapid thermal decomposition of tert-butyl hydroperoxide ((CH3)3–CO–OH), and monitored by narrow line width laser absorption of the well-characterized R1(5) electronic transition of the OH A–X (0,0) electronic system near 306.7 nm. Results show that allene reacts faster with OH radicals than propyne over the temperature range of this study. Measured rate coefficients can be expressed in Arrhenius form as follows: kallene+OH(T) = 8.51(±0.03) × 10–22T3.05 exp(2215(±3)/T), T = 843–1352 K; kpropyne+OH(T) = 1.30(±0.07) × 10–21T3.01 exp(1140(±6)/T), T = 846–1335 K.

  17. 34 CFR 84.105 - Does this part apply to me?

    Science.gov (United States)

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false Does this part apply to me? 84.105 Section 84.105 Education Office of the Secretary, Department of Education GOVERNMENTWIDE REQUIREMENTS FOR DRUG-FREE... Education; or (2) A(n) ED awarding official. (See definitions of award and recipient in §§ 84.605 and 84.660...

  18. Signatures of non-adiabatic dynamics in the fine-structure state distributions of the OH(X{sup ~}/A{sup ~}) products in the B-band photodissociation of H{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Linsen [Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Institute of Theoretical and Computational Chemistry, Nanjing University, Nanjing 210093 (China); Xie, Daiqian, E-mail: dqxie@nju.edu.cn, E-mail: hguo@unm.edu [Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Institute of Theoretical and Computational Chemistry, Nanjing University, Nanjing 210093 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Guo, Hua, E-mail: dqxie@nju.edu.cn, E-mail: hguo@unm.edu [Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

    2015-03-28

    A detailed quantum mechanical characterization of the photodissociation dynamics of H{sub 2}O at 121.6 nm is presented. The calculations were performed using a full-dimensional wave packet method on coupled potential energy surfaces of all relevant electronic states. Our state-to-state model permits a detailed analysis of the OH(X{sup ~}/A{sup ~}) product fine-structure populations as a probe of the non-adiabatic dissociation dynamics. The calculated rotational state distributions of the two Λ-doublet levels of OH(X{sup ~}, v = 0) exhibit very different characteristics. The A′ states, produced mostly via the B{sup ~}→X{sup ~} conical intersection pathway, have significantly higher populations than the A″ counterparts, which are primarily from the B{sup ~}→A{sup ~} Renner-Teller pathway. The former features a highly inverted and oscillatory rotational state distribution, while the latter has a smooth distribution with much less rotational excitation. In good agreement with experiment, the calculated total OH(X{sup ~}) rotational state distribution and anisotropy parameters show clear even-odd oscillations, which can be attributed to a quantum mechanical interference between waves emanating from the HOH and HHO conical intersections in the B{sup ~}→X{sup ~} non-adiabatic pathway. On the other hand, the experiment-theory agreement for the OH(A{sup ~}) fragment is also satisfactory, although some small quantitative differences suggest remaining imperfections of the ab initio based potential energy surfaces.

  19. Warm H2O and OH Disk Emission in V1331 Cyg

    Science.gov (United States)

    Doppmann, Greg W.; Najita, Joan R.; Carr, John S.; Graham, James R.

    2011-09-01

    We present high-resolution (R = 24, 000) L-band spectra of the young intermediate-mass star V1331 Cyg obtained with NIRSPEC on the Keck II telescope. The spectra show strong, rich emission from water and OH that likely arises from the warm surface region of the circumstellar disk. We explore the use of the new BT2 water line list in fitting the spectra, and we find that it does a much better job than the well-known HITRAN water line list in the observed wavelength range and for the warm temperatures probed by our data. By comparing the observed spectra with synthetic disk emission models, we find that the water and OH emission lines have similar widths (FWHM ~= 18 km s-1). If the line widths are set by disk rotation, the OH and water emission lines probe a similar range of disk radii in this source. The water and OH emission are consistent with thermal emission for both components at a temperature ~1500 K. The column densities of the emitting water and OH are large, ~1021 cm-2 and ~1020 cm-2, respectively. Such a high column density of water is more than adequate to shield the disk midplane from external UV irradiation in the event of complete dust settling out of the disk atmosphere, enabling chemical synthesis to continue in the midplane despite a harsh external UV environment. The large OH-to-water ratio is similar to expectations for UV irradiated disks, although the large OH column density is less easily accounted for. Data presented herein were obtained at the W. M. Keck Observatory from telescope time allocated to the National Aeronautics and Space Administration through the agency's scientific partnership with the California Institute of Technology and the University of California. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  20. New roles for the OHS representatives - from employee representation to problem-solving

    DEFF Research Database (Denmark)

    Hasle, Peter; Seim, Rikke

    2014-01-01

    an area of conflict. The role of the OHS reps has accordingly changed to focus on solving specific problems at the workplace. Both management and colleagues consider the OHS reps as a resource that can be utilized to manage the work environment. The consequences of this development for the employees......The changing role of occupational health and safety representatives (OHS reps) is studied in Danish enterprises and the results indicate that representation, and especially negotiation on behalf of colleagues, has diminished. The work environment is mainstreamed in many enterprises and it is rarely...

  1. Thermal transformation of synthetic borax, Na2[B4O5(OH)4]x8H2O

    International Nuclear Information System (INIS)

    Abdullaev, G.K.

    1981-01-01

    Using the methods of high temperature roentgenography and derivatography thermal transformation of synthetic borax is studied. It is established that borax dehydration proceeds in four stages (50-80, 80-100, 100-150 and 150-500 deg C) with the formation of three intermediate crystalline hydrate forms (one stable and two unstable) and one final stable crystalline phase. The stable crystalline phases correspond to synthetic tincalconite Na 2 [B 4 O 5 (OH) 4 ]x3H 2 O and sodium tetraborate Na 2 B 4 O 7 . Thermal transformation of borax into tincalconite and sodium tetraborate is explained on the basis of their crystal structures [ru

  2. Widespread distribution of OH/H2O on the lunar surface inferred from spectral data.

    Science.gov (United States)

    Bandfield, Joshua L; Poston, Michael J; Klima, Rachel L; Edwards, Christopher S

    2018-01-01

    Remote sensing data from lunar orbiters have revealed spectral features consistent with the presence of OH or H 2 O on the lunar surface. Analyses of data from the Moon Mineralogy Mapper spectrometer onboard the Chandryaan-1 spacecraft have suggested that OH/H 2 O is recycled on diurnal timescales and persists only at high latitudes. However, the spatial distribution and temporal variability of the OH/H 2 O, as well as its source, remain uncertain. Here we incorporate a physics-based thermal correction into analysis of reflectance spectra from the Moon Mineralogy Mapper and find that prominent absorption features consistent with OH/H 2 O can be present at all latitudes, local times, and surface types examined. This suggests the widespread presence of OH/H 2 O on the lunar surface without significant diurnal migration. We suggest that the spectra are consistent with the production of OH in space weathered materials by the solar wind implantation of H + and formation of OH at crystal defect sites, as opposed to H 2 O sourced from the lunar interior. Regardless of the specific composition or formation mechanism, we conclude that OH/H 2 O can be present on the Moon under thermal conditions more wide-ranging than previously recognized.

  3. The Recovery of Uranium From The Rejected Fuel Plate Dispersion Type of U3O8-Al and U3Si2Al by NaOH

    International Nuclear Information System (INIS)

    Widodo, G; Aji, D

    1998-01-01

    The recovery of uranium from the rejected fuel plate dispersion type of U 3 O 8 -AI And U 3 Si 2 -AI with a dissolution has been performed.Each of 5 fragment of fuel plate dispersion of U 3 O 8 -AI or U 3 Si 2 Al of 1x4 cm size was put in the distilled glass content of 250 ml NaOH solution whit The concentration variation 10,15,20,25,and 30%,and than was heated at temperature of 102 o C and was stirred constantly by magnetic stirred.Uranium in the form of U 3 O 8 or U 3 Si 2 was separated by filtration and Either residu and filtrate was analyzed by potentiometry using modified Devies Gray method. From the experiment data it was found in the residu that presentation of uranium was 83.99-84.05% and 84.67-86.556% while in filtrate it was found 53.90 ppm and 69.3 ppm

  4. Formation of Mg(OH)2 nanowhiskers on LTA zeolite surfaces using a sol–gel method

    KAUST Repository

    Liu, Junqiang

    2011-09-20

    A facile three step sol-gel-precipitation process is used to synthesize Mg(OH)2 nanowhiskers on micron-sized zeolite 5A particle surfaces at room temperature. The putative amorphous gelation product, Mg(OH) n(OR)2-n, forms first by a controlled hydrolysis and condensation reaction involving magnesium isopropoxide and water, ultimately leading to precipitation to form Mg(OH)2 structures on the zeolite surface. The optimum conditions for one dimensional Mg(OH)2 whisker formation are found to be six times the stoichiometric amount of water using 1 M HCl as the catalyst for the sol-gel reaction. The one-dimensional Mg(OH) 2 whiskers have an average diameter of 5-10 nm and length of 50-100 nm. The zeolite micropores are not affected by the Mg(OH)2 whiskers formed on the surface. The surface roughened zeolite 5A, with a Mg(OH) 2 content of about 9 wt%, showed improved adhesion between the zeolite and the polymer in a mixed-matrix composite membrane. © 2011 Springer Science+Business Media, LLC.

  5. Facile approach to synthesize Ni(OH)2 nanoflakes on MWCNTs for high performance electrochemical supercapacitors

    International Nuclear Information System (INIS)

    Shahid, Muhammad; Liu Jingling; Shakir, Imran; Warsi, Muhammad Farooq; Nadeem, Muhammad; Kwon, Young-Uk

    2012-01-01

    Highlights: ► Deposition of ultra-thin Ni(OH) 2 nanoflakes on MWCNTs. ► Full utilization of the Ni(OH) 2 nanoflakes which provide maximum pseudocapacitance while minimizing the high surface area. ► The ultra-thin layer of Ni(OH) 2 nanoflakes on highly conductive MWCNTs is favorable for fast ion and electron transfer. ► The ultra-thin layer of Ni(OH) 2 nanoflakes on MWCNTs exhibited good cycling stability and lifetime. - Abstract: Ultrathin nanoflakes of Ni(OH) 2 were synthesized onto multi-walled carbon nanotubes (MWCNTs) by simple low cost chemically precipitation method for high performance electrochemical supercapacitor applications. The synthesized ultrathin Ni(OH) 2 exhibit high specific capacitance of 1735 Fg −1 at a scan rate of 5 mV s −1 with excellent rate capability. This high performance of Ni(OH) 2 nanoflakes was attributed to its complete accessibility to the electrolyte and maximum utilization of metal hydroxides. Findings of this work suggest that synthesized electrodes offer low-cost and scalable solution for high-performance energy storage devices.

  6. Electrochemical deposition of Mg(OH2/GO composite films for corrosion protection of magnesium alloys

    Directory of Open Access Journals (Sweden)

    Fengxia Wu

    2015-09-01

    Full Text Available Mg(OH2/graphene oxide (GO composite film was electrochemical deposited on AZ91D magnesium alloys at constant potential. The characteristics of the Mg(OH2/GO composite film were investigated by scanning electron microscope (SEM, energy-dispersive X-ray spectrometry (EDS, X-ray diffractometer (XRD and Raman spectroscopy. It was shown that the flaky GO randomly distributed in the composite film. Compared with the Mg(OH2 film, the Mg(OH2/GO composite film exhibited more uniform and compact structure. Potentiodynamic polarization tests revealed that the Mg(OH2/GO composite film could significantly improve the corrosion resistance of Mg(OH2 film with an obvious positive shift of corrosion potential by 0.19 V and a dramatic reduction of corrosion current density by more than one order of magnitude.

  7. Atmospheric Chemistry of cis-CF3CH=CHF: Kinetics of reactions with OH radicals and O3 and products of OH radical initiated oxidation

    DEFF Research Database (Denmark)

    Nilsson, Elna Johanna Kristina; Nielsen, Ole John; Johnson, Matthew Stanley

    2009-01-01

    Long path length FTIR-smog chamber techniques were used to measure k(OH + cis-CF3CH@CHF) = (1.20 ± 0.14) 1012 and k(O3 + cis-CF3CH@CHF) = (1.65 ± 0.16) 1021 cm3 molecule 1 s1 in 700 Torr of N2/O2 diluent at 296 K. The OH initiated oxidation of cis-CF3CH@CHF gives CF3CHO and HCOF in molar yields w...

  8. Seasonal observations of OH and HO2 in the remote tropical marine boundary layer

    Directory of Open Access Journals (Sweden)

    Z. L. Fleming

    2012-02-01

    Full Text Available Field measurements of the hydroxyl radical, OH, are crucial for our understanding of tropospheric chemistry. However, observations of this key atmospheric species in the tropical marine boundary layer, where the warm, humid conditions and high solar irradiance lend themselves favourably to production, are sparse. The Seasonal Oxidant Study at the Cape Verde Atmospheric Observatory in 2009 allowed, for the first time, seasonal measurements of both OH and HO2 in a clean (i.e. low NOx, tropical marine environment. It was found that concentrations of OH and HO2 were typically higher in the summer months (June, September, with maximum daytime concentrations of ~9 × 106 and 4 × 108 molecule cm−3, respectively – almost double the values in winter (late February, early March. HO2 was observed to persist at ~107 molecule cm−3 through the night, but there was no strong evidence of nighttime OH, consistent with previous measurements at the site in 2007. HO2 was shown to have excellent correlations (R2 ~ 0.90 with both the photolysis rate of ozone, J(O1D, and the primary production rate of OH, P(OH, from the reaction of O(1D with water vapour. The analogous relations of OH were not so strong (R2 ~ 0.6, but the coefficients of the linear correlation with J(O1D in this study were close to those yielded from previous works in this region, suggesting that the chemical regimes have similar impacts on the concentration of OH. Analysis of the variance of OH and HO2 across the Seasonal Oxidant Study suggested that ~70% of the total variance could be explained by diurnal behaviour, with ~30% of the total variance being due to changes in air mass.

  9. International frameworks, national problems: mining OHS regulation in South Africa and Australia

    CSIR Research Space (South Africa)

    Shaw, A

    2011-12-01

    Full Text Available Effective occupational health and safety (OHS) regulation is a critical foundation for healthy and safe mining, but the nature of the risks and the diversity of the mining industry create particular challenges for OHS regulation and enforcement...

  10. From employee representation to problem-solving: Mainstreaming OHS management

    DEFF Research Database (Denmark)

    Hasle, Peter; Seim, Rikke; Refslund, Bjarke

    2016-01-01

    The role of occupational health and safety representatives is changing. A study in 60 Danish enterprises indicates that representation, and especially negotiation on behalf of colleagues, has diminished. The work environment is mainstreamed in many enterprises and is rarely an area of conflict....... The role of OHS representatives has accordingly changed to focus on solving specific problems in the workplace as an integrated part of daily operations. Both management and colleagues consider the OHS representatives as a resource that can be utilized to manage the work environment. The consequences...

  11. Penggunaan Katalis NaOH dalam Proses Transesterifikasi Minyak Kemiri menjadi Biodiesel

    Directory of Open Access Journals (Sweden)

    Farid Mulana

    2011-12-01

    Full Text Available Research on biodiesel production from hazelnut oil by transesterification process using NaOH catalyst was one of the efforts for renewable energy research. The purpose of this study was to determine the effect of NaOH catalyst and the ratio of hazelnut oil to methanol on the production of biodiesel via transesterification process. The transesterification process was carried out in a stirred reactor equipped by a condenser with speed of 200 rpm, temperature of 60°C and the operating time of 90 minutes. The results indicated that biodiesel could be produced from hazelnut oil through transesterification process with the highest yield of 81.7% that was obtained on the use of 2% wt. of NaOH catalyst and the mole ratio of oil to methanol of 1:9. Viscosity, density, and acid number of biodiesel obtained in this study met the Indonesia National Standard for biodiesel as SNI 04-7182-2006, therefore hazelnut oil produced biodiesel could potentially be an alternative diesel fuel. Keywords: hazelnut oil, biodiesel, transesterification, NaOH catalyst

  12. OHS consultants as facilitators of learning processes in client enterprises

    DEFF Research Database (Denmark)

    Broberg, Ole

    2004-01-01

    emphasis on initiating learning processes in the client enter-prise in a way that will develop the OHS management capabilities of that enterprise. This presentation is based on a research program focussing on how OHS consultants go about when they are involved in consultancy on technological change...... processes in client enter-prises. Specifically the learning perspective will be touched upon. The research programme included four cases in different client enterprises: 1) New tech-nology in a logistic department of a brewery, 2) new pharmaceutical process facility, 3) design of a new catering centre...... in another institution than pre-sent the users to blueprints and then ask them to put forward technical suggestions to im-prove the workplace design. In conclusion, the study pointed out that the OHS consultants had different work practices on learning aspects of their consultancy. Several constraining...

  13. Theoretical and experimental insights into the ·OH-mediated mineralization mechanism of flutriafol

    International Nuclear Information System (INIS)

    Liu, Siqi; Zhou, Xiezhen; Han, Weiqing; Li, Jiansheng; Sun, Xiuyun; Shen, Jinyou; Wang, Lianjun

    2017-01-01

    Highlights: • A complete ·OH-mediated degradation pathway of flutriafol is proposed. • Computational approach is effective to reveal the favorable transformation process. • The electrochemical experiments well verify the theoretical results. - Abstract: Flutriafol is one of the widely used triazole fungicides in global pesticides market, and its degradation mechanisms are important to develop powerful technologies to remove it. Insight into the kinetics and mechanisms of ·OH-mediated mineralization of flutriafol have been obtained using quantum chemical calculation and electrochemical experiment methods. The complete ·OH-mediated degradation pathway of flutriafol was proposed by density functional theory (DFT) simulation and the potential energy surface was mapped out for possible reactions. On the basis of DFT calculations, the optimal ·OH-mediated mineralization mechanism of flutriafol was revealed, and a series of intermediates were observed accumulated in the degradation process, most significance among which were (2-fluorophenyl) (4-fluorophenyl)-Methanone, phenol, dihydroxybenzenes, benzoquinones, muconic acids, maleic acids, oxalic acids and formic acid. To give deeper insight into the ·OH-mediated reaction mechanism, the electrostatic potential (ESP) and average local ionization energy (ALIE) analysis were conducted for o-benzoquinone and p-benzoquinone. The proposed mechanism was further validated by electrochemical experiments at TiO_2-NTs/SnO_2-Sb/PbO_2 anode. The main intermediates were identified and quantified by experimental method, indicating that the proposed ·OH-mediated degradation mechanism derived from DFT calculations was feasible. These detailed findings could be instrumental for a comprehensive understanding of the ·OH-mediated mineralization mechanism of flutriafol and the similar contaminants.

  14. Anomalou OH emission in galactic star-forming regions - A clue to the megamaser phenomenon?

    International Nuclear Information System (INIS)

    Mirabel, I.F.; Rodriguez, L.F.; Ruiz, A.

    1989-01-01

    The detection of spatially extended, anomalous OH emission in galactic star-forming regions is reported. This OH emission is similar to, although much weaker than, that produced by extragalactic megamasers. This new type of galactic emission may provide clues to elucidate the nature of the extragalactic OH megamaser phenomenon observed in luminous IR galaxies. 10 refs

  15. High-temperature crystal chemistry of layered calcium borosilicates: CaBSiO4(OH) (datolite), Ca4B5Si3O15(OH)5 (`bakerite') and Ca2B2SiO7 (synthetic analogue of okayamalite)

    Science.gov (United States)

    Krzhizhanovskaya, Maria G.; Gorelova, L. A.; Bubnova, R. S.; Pekov, I. V.; Krivovichev, S. V.

    2018-05-01

    The high-temperature behaviour of three Ca borosilicates has been studied by in situ powder high-temperature X-ray diffraction (HTXRD), differential scanning calorimetry and thermogravimetry in the temperature range 30-900 °C for natural samples of datolite, CaBSiO4(OH), and `bakerite', Ca4B5Si3O15(OH)5, and a synthetic analogue of okayamalite, Ca2B2SiO7. The latter was obtained by heating datolite at 800 °C for 5 h. Datolite and bakerite start to dehydroxylate above 700 and 500 °C, respectively, and decompose fully to form a high-temperature modification of okayamalite, HT-Ca2B2SiO7, and wollastonite, CaSiO3 at about 730 °C. Above 900 °C, HT-okayamalite decomposes with the formation of wollastonite, CaSiO3, and metaborate CaB2O4. The latter melts at about 990 °C. Above 1000 °C, only the existence of wollastonite, CaSiO3 and cristobalite, SiO2 was observed. According to the HTXRD data, in the temperature range 30-500 °C, datolite and `bakerite' demonstrate very similar and relatively low volumetric thermal expansion: α v = 29 and 27 × 10-6 °C-1, respectively. A high thermal expansion anisotropy ( α max/ α min 3) is caused by both the layered character of the crystal structures and the shear deformations of their monoclinic unit cells. The direction of maximum expansion is intermediate between the normal direction to the layers and the ( a + c) vector. A possible transformation mechanism from the datolite to the okayamalite structure topology is proposed from geometrical considerations. The synthetic analogue of okayamalite, Ca2B2SiO7, undergoes a reversible polymorphic transition at about 550 °C with a decrease in symmetry from tetragonal to orthorhombic. The crystal structure of the high-temperature (HT) modification of okayamalite was solved from the powder-diffraction data [900 °C: P21212, a = 7.3361(4), b = 7.1987(4), c = 4.8619(4) Å, V = 256.76(3) Å3, R wp = 6.61, R Bragg = 2.68%].

  16. Effects of dipotassium-trioxohydroxytetrafluorotriborate, K2[B3O3F4OH], on cell viability and gene expression of common human cancer drug targets in a melanoma cell line.

    Science.gov (United States)

    Pojskic, Lejla; Haveric, Sanin; Lojo-Kadric, Naida; Hadzic, Maida; Haveric, Anja; Galic, Zoran; Galic, Borivoj; Vullo, Daniela; Supuran, Claudiu T; Milos, Mladen

    2016-12-01

    Recently it was found that dipotassium-trioxohydroxytetrafluorotriborate, K2(B3O3F4OH), is a potent and highly specific inhibitor of precancerous cell processes. We conducted gene expression profiling of human melanoma cells before and after treatment with two concentrations (0.1 and 1 mM) of this boron inorganic derivative in order to assess its effects on deregulation of genes associated with tumor pathways. Parallel trypan blue exclusion assay was performed to assess the cytotoxicity effects of this chemical. Treatment with K2(B3O3F4OH) induced a significant decrease of cell viability in melanoma cellline at both tested concentrations. Furthermore, these treatments caused deregulation of more than 30 genes known as common anti-tumor drug targets. IGF-1 and hTERT were found to be significantly downregulated and this result may imply potential use of K2(B3O3F4OH) as an inhibitor or human telomerase and insulin-like growth factor 1, both of which are associated with various tumor pathways.

  17. Cane molasses and NaOH teated bagacillo diets for lambs | Chicco ...

    African Journals Online (AJOL)

    Cane molasses and NaOH teated bagacillo diets for lambs. C.F. Chicco, G Garcia, C Fernandez, C.R. Prays. Abstract. The eftect of alkali-treated bag acillo in diets varying in proportion of bagacillo and mollasses was studied in lambs. The bagacillo was treated with a concentration solution of NaOH in a horizontald rum-type ...

  18. Detection of OH on photolysis of styrene oxide at 193 nm in gas phase

    Science.gov (United States)

    Kumar, Awadhesh; SenGupta, Sumana; Pushpa, K. K.; Naik, P. D.; Bajaj, P. N.

    2006-10-01

    Photodissociation of styrene oxide at 193 nm in gas phase generates OH, as detected by laser-induced fluorescence technique. Under similar conditions, OH was not observed from ethylene and propylene oxides, primarily because of their low absorption cross-sections at 193 nm. Mechanism of OH formation involves first opening of the three-membered ring from the ground electronic state via cleavage of either of two C sbnd O bonds, followed by isomerization to enolic forms of phenylacetaldehyde and acetophenone, and finally scission of the C sbnd OH bond of enols. Ab initio molecular orbital calculations support the proposed mechanism.

  19. Synthesis Magnesium Hydroxide Nanoparticles and Cellulose Acetate- Mg(OH2-MWCNT Nanocomposite

    Directory of Open Access Journals (Sweden)

    M. Ghorbanali

    2015-04-01

    Full Text Available Mg(OH2 nanoparticles were synthesized by a rapid microwave reaction. The effect of sodium dodecyl sulfonate (SDS as anionic surfactant and cetyl tri-methyl ammonium bromide (CTAB as cationic surfactant on the morphology of magnesium hydroxide nanostructures was investigated. Multi wall carbon nano tubes was organo-modified for better dispersion in cellulose acetate matrix. The influence of Mg(OH2 nanoparticles and modified multi wall carbon nano tubes (MWCNT on the thermal stability of the cellulose acetate (CA matrix was studied using thermo-gravimetric analysis (TGA. Nanostructures were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM and Fourier transform infrared (FT-IR spectroscopy. Thermal decomposition of the nanocomposites shift towards higher temperature in the presence of Mg(OH2 nanostructures. The enhancement of thermal stability of nanocomposites is due to the endothermic decomposition of Mg(OH2 and release of water which dilutes combustible gases.

  20. Formation of hydroxyl radical (sm-bulletOH) in illuminated surface waters contaminated with acidic mine drainage

    International Nuclear Information System (INIS)

    Allen, J.M.; Lucas, S.; Allen, S.K.

    1996-01-01

    Formation rates and steady-state concentrations of hydroxyl radical ( sm-bullet OH) in illuminated surface water samples collected in west-central Indiana that receive acidic mine drainage runoff are reported. Formation rates for sm-bullet OH in samples were measured by the addition of 1 x 10 -3 M benzene prior to illuminate in order to effectively scavenge all of the sm-bullet OH formed, thereby yielding phenol. The sm-bullet OH formation rates were calculated from the measured phenol formation rates. Steady-state concentrations of sm-bullet OH were measured by the addition of 5 x 10 -7 M nitrobenzene to the samples prior to illumination. Estimated sunlight sm-bullet OH formation rates range from 16 microM h -1 to 265 microM h -1 . Estimated sunlight steady-state sm-bullet OH concentrations range from 6.7 x 10 -15 to 4.0 x 10 -12 M. Both the formation rates and steady-state concentrations for sm-bullet OH are thus two to three orders of magnitude higher than values reported in the literature for other sunlit surface water samples. Due to the very high rates of formation and steady-state concentrations for sm-bullet OH in these samples, the authors conclude that aqueous-phase reactions involving sm-bullet OH represent a significant pathway by which organic pollutants in illuminated surface waters receiving acidic mine drainage runoff may be consumed

  1. Acid indium strontium phosphate SrIn2[PO3(OH)]4: synthesis and crystal structure

    International Nuclear Information System (INIS)

    Rusakov, D.A.; Bobylev, A.P.; Komissarova, L.N.; Filaretov, A.A.; Danilov, V.P.

    2007-01-01

    Acid indium-strontium phosphate SrIn 2 [PO 3 (OH)] 4 is synthesized and characterized. Crystal structure and lattice parameters ate determined. In atoms in SrIn 2 [PO 3 (OH)] 4 structure are in distorted InO 6 octahedrons and form with PO 3 (OH) tetrahedrons mixed paraskeleton {In 2 [PO 3 (OH)] 4 } 3∞ 2- with emptinesses occupied by big Sr 2+ cations. The compound is thermally stable up to 400 Deg C [ru

  2. 15 years of VLT/UVES OH intensities and temperatures in comparison with TIMED/SABER data

    Science.gov (United States)

    Noll, Stefan; Kimeswenger, Stefan; Proxauf, Bastian; Unterguggenberger, Stefanie; Kausch, Wolfgang; Jones, Amy M.

    2017-10-01

    The high-resolution echelle spectrograph UVES of the Very Large Telescope at Cerro Paranal in Chile has been regularly operated since April 2000. Thus, UVES archival data originally taken for astronomical projects but also including sky emission can be used to study airglow variations on a time scale longer than a solar cycle. Focusing on OH emission and observations until March 2015, we considered about 3000 high-quality spectra from two instrumental set-ups centred on 760 and 860 nm, which cover about 380 nm each. These data allowed us to measure line intensities for several OH bands in order to derive band intensities and rotational temperatures for different upper vibrational levels as a function of solar activity and observing date. The results were compared with those derived from emission and temperature profile data of the radiometer SABER on the TIMED satellite taken in the Cerro Paranal area between 2002 and 2015. In agreement with the SABER data, the long-term variations in OH intensity and temperature derived from the UVES data are dominated by the solar cycle, whereas secular trends appear to be negligible. Combining the UVES and SABER results, the solar cycle effects for the OH intensity and temperature are about 12-17% and 4-5 K per 100 sfu and do not significantly depend on the selected OH band. The data also reveal that variations of the effective OH emission layer height and air density can cause significant changes in the OH rotational temperatures due to a varying ratio of OH thermalising collisions by air molecules and OH radiation, deactivation, and destruction processes which impede the rotational relaxation. However, this effect appears to be of minor importance for the explanation of the rotational temperature variations related to the solar activity cycle, which causes only small changes in the OH emission profile.

  3. Toward Clarity in Clinical Vitamin D Status Assessment: 25(OH)D Assay Standardization.

    Science.gov (United States)

    Binkley, Neil; Carter, Graham D

    2017-12-01

    Widespread variation in 25-hydroxyvitamin D (25(OH)D) assays continues to compromise efforts to develop clinical and public health guidelines regarding vitamin D status. The Vitamin D Standardization Program helps alleviate this problem. Reference measurement procedures and standard reference materials have been developed to allow current, prospective, and retrospective standardization of 25(OH)D results. Despite advances in 25(OH)D measurement, substantial variability in clinical laboratory 25(OH)D measurement persists. Existing guidelines have not used standardized data and, as a result, it seems unlikely that consensus regarding definitions of vitamin D deficiency, inadequacy, sufficiency, and excess will soon be reached. Until evidence-based consensus is reached, a reasonable clinical approach is advocated. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Comprehensive Theoretical Studies on the Reaction of 1-Bromo-3,3,3-trifluoropropene with OH Free Radicals

    Directory of Open Access Journals (Sweden)

    Yan Tian

    2013-07-01

    Full Text Available The potential energy surfaces (PES for the reaction of 1-bromo-3,3,3-trifluoropropene (CF3CHCBrH with hydroxyl (OH free radicals is probed theoretically at the CCSD/aug-cc-pVDZ//B3LYP/6-311++G(d,p level of theory. All the possible stationary and first-order saddle points along the reaction paths were verified by the vibrational analysis. The calculations account for all the product channels. Based on the calculated CCSD/aug-cc-pVDZ potential energy surface, the possible reaction mechanism is discussed. Six distinct reaction pathways of 1-bromo-3,3,3-trifluoropropene (BTP with OH are investigated. The geometries, reaction enthalpies and energy barriers are determined. Canonical transition-state theory with Wigner tunneling correction was used to predict the rate constants for the temperature range of 290–3,000 K without any artificial adjustment, and the computed rate constants for elementary channels can be accurately fitted with three-parameter Arrhenius expressions. OH addition reaction channel and the H atom abstraction channels related to the carbon-carbon double bond are found to be the main reaction channels for the reaction of 1-bromo-3,3,3-trifluoropropene (CF3CHCBrH with hydroxyl (OH free radicals while the products leading to CF3CHCH + BrOH and COHF2CHCBrH + F play a negligible role.

  5. Impact of NOx and OH on secondary organic aerosol formation from β-pinene photooxidation

    Directory of Open Access Journals (Sweden)

    M. Sarrafzadeh

    2016-09-01

    Full Text Available In this study, the NOx dependence of secondary organic aerosol (SOA formation from photooxidation of the biogenic volatile organic compound (BVOC β-pinene was comprehensively investigated in the Jülich Plant Atmosphere Chamber. Consistent with the results of previous NOx studies we found increases of SOA yields with increasing [NOx] at low-NOx conditions ([NOx]0  <  30 ppb, [BVOC]0 ∕ [NOx]0  >  10 ppbC ppb−1. Furthermore, increasing [NOx] at high-NOx conditions ([NOx]0  >  30 ppb, [BVOC]0 ∕ [NOx]0  ∼  10 to  ∼  2.6 ppbC ppb−1 suppressed the SOA yield. The increase of SOA yield at low-NOx conditions was attributed to an increase of OH concentration, most probably by OH recycling in NO + HO2  →  NO2 + OH reaction. Separate measurements without NOx addition but with different OH primary production rates confirmed the OH dependence of SOA yields. After removing the effect of OH concentration on SOA mass growth by keeping the OH concentration constant, SOA yields only decreased with increasing [NOx]. Measuring the NOx dependence of SOA yields at lower [NO] ∕ [NO2] ratio showed less pronounced increase in both OH concentration and SOA yield. This result was consistent with our assumption of OH recycling by NO and to SOA yields being dependent on OH concentrations. Our results furthermore indicated that NOx dependencies vary for different NOx compositions. A substantial fraction of the NOx-induced decrease of SOA yields at high-NOx conditions was caused by NOx-induced suppression of new particle formation (NPF, which subsequently limits the particle surface where low volatiles condense. This was shown by probing the NOx dependence of SOA formation in the presence of seed particles. After eliminating the effect of NOx-induced suppression of NPF and NOx-induced changes of OH concentrations, the remaining effect of NOx on the SOA yield from

  6. Synthesis, crystal structure and optical properties of two new layered cadmium iodates: Cd(IO3)X (X=Cl, OH)

    International Nuclear Information System (INIS)

    Yang, Bing-Ping; Mao, Jiang-Gao

    2014-01-01

    Systematic explorations of new compounds in the cadmium iodate system by hydrothermal reactions led to two layered iodates, namely, Cd(IO 3 )X (X=Cl, OH). Cd(IO 3 )Cl crystallizes in the orthorhombic space group Cmca (No. 64) whereas Cd(IO 3 )(OH) crystallizes in the orthorhombic space group Pnma (No. 62). Cd(IO 3 )Cl displays a unique double layered structure composed of 1 ∞ [Cd−O 3 Cl] n chains. Cadmium octahedrons form a 1D chain along the a-axis through edge sharing, and such chains are further interconnected via IO 3 groups to form a special double layer on (020) plane. Cd(IO 3 )(OH) also exhibits a layered structure that is composed of cadmium cations, IO 3 groups and hydroxyl ions. Within a layer, chains of CdO 6 edge-shared octahedra are observed along the b-axis. And these chains are connected by IO 3 groups into a layer parallel to the bc plane. Spectroscopic characterizations, elemental analysis, and thermogravimetric analysis for the reported two compounds are also presented. - Graphical abstract: Two new layered cadmium iodates Cd(IO 3 )X (X=Cl, OH) are reported. Cd(IO 3 )Cl features a unique double layered structure whereas Cd(IO 3 )(OH) displays an ordinary layered structure. - Highlights: • Two new layered cadmium iodates Cd(IO 3 )X (X=Cl, OH) are reported. • Cd(IO 3 )Cl features a unique double layered structure. • Cd(IO 3 )(OH) displays an ordinary layered structure. • The spectroscopic and thermal properties have been studied in detail

  7. Fast repair of oxidizing OH adducts of DNA by hydroxycinnamic acid derivatives. A pulse radiolytic study

    International Nuclear Information System (INIS)

    Yue Jiang; Lin Weizhen; Yao Side; Lin Nianyun; Zhu Dayuan

    1999-01-01

    Using pulse radiolytic techniques, it has been demonstrated that the interactions of oxidizing OH adducts of DNA (ssDNA and dsDNA), polyA and polyG with hydroxycinnamic acid derivatives proceed via an electron transfer process (k=5-30x10 8 dm 3 mol -1 s -1 ). In addition, the rates for fast repair of OH adducts of dAMP, polyA and DNA (ssDNA and dsDNA) are slower than the corresponding rates for the rest OH adducts of DNA constituents. The slower rates for repair of oxidizing OH adducts of dAMP may be the rate determining step during the interaction of hydroxycinnamic acid derivatives with OH adducts of DNA containing the varieties of OH adducts of DNA constituents

  8. Dielectric, optical and mechanical studies of phenolic polyene OH1 organic electrooptic crystal

    Science.gov (United States)

    Bharath, D.; Kalainathan, S.

    2014-11-01

    2-{3-[2-(4-Hydroxyphenyl) vinyl]-5, 5-dimethylcyclo-hex-2-en-1-ylidene}malononitrile (OH1) phenolic locked polyene organic material has been synthesized by the Knoevenagel condensation method. OH1 single crystals were grown in methanol by a slow evaporation method. In order to avoid the multinucleation and reduce the metastable zone width, phosphoric acid is added in different concentrations. The linear optical property of OH1 crystal has been studied using UV-vis-NIR spectroscopy in the wavelength range 190-1100 nm and optical constants are calculated theoretically. The magnitude of nonlinear refractive index (10-12 m2/W), nonlinear absorption (10-6 m/W) and third order nonlinear susceptibility (10-6 esu) has been studied using a Z-scan technique. Dielectric property of OH1 crystal has been studied in frequency range 50 Hz-5 MHz. Photoluminescence spectrum was recorded using a xenon lamp in the range of 450-700 nm. Laser optical damage threshold of OH1 crystal was obtained (0.62 GW/cm2) using a pulsed Nd-YAG laser (1064 nm) of repetition rate 10 ns.

  9. Existence of a solid solution from brucite to {beta}-Co(OH){sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Giovannelli, F., E-mail: fabien.giovannelli@univ-tours.fr [LEMA, UMR 6157 CNRS - CEA, Universite Francois Rabelais, 15 rue de la chocolaterie, 41000 Blois (France); Delorme, F.; Autret-Lambert, C. [LEMA, UMR 6157 CNRS - CEA, Universite Francois Rabelais, 15 rue de la chocolaterie, 41000 Blois (France); Seron, A.; Jean-Prost, V. [BRGM, 3 Avenue Claude Guillemin, BP 36009, 45060 Orleans Cedex 2 (France)

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer A solid solution exist between Mg(OH){sub 2} and {beta}-Co(OH){sub 2}. Black-Right-Pointing-Pointer Synthesis has been performed through an easy and fast coprecipitation route. Black-Right-Pointing-Pointer No long range-ordering of the cations occurs. -- Abstract: This study shows that between brucite (Mg(OH){sub 2}) and {beta}-Co(OH){sub 2}, all the compositions are possible. The solid solution Mg{sub 1-x}Co{sub x}(OH){sub 2} has been synthesized by an easy and fast coprecipitation route and characterized by XRD and TEM. Single phase powders have been obtained. The particles exhibit platelets morphology with a size close to one hundred nanometers. XRD analysis shows an evolution of the cell parameters when x increases and demonstrates that no ordering of the cations occurs. However, extra reflections on TEM electron diffraction patterns seem to indicate that local ordering can exist. The compounds issued from this solid solution could be good candidates as precursors in order to obtain Mg-Co mixed oxide with all possible cationic ratios.

  10. Mechanistic and kinetic studies on the OH-initiated atmospheric oxidation of fluoranthene

    International Nuclear Information System (INIS)

    Dang, Juan; Shi, Xiangli; Zhang, Qingzhu; Hu, Jingtian; Chen, Jianmin; Wang, Wenxing

    2014-01-01

    The atmospheric oxidation of polycyclic aromatic hydrocarbons (PAHs) can generate toxic derivatives which contribute to the carcinogenic potential of particulate organic matter. In this work, the mechanism of the OH-initiated atmospheric oxidation of fluoranthene (Flu) was investigated by using high-accuracy molecular orbital calculations. All of the possible oxidation pathways were discussed, and the theoretical results were compared with the available experimental observation. The rate constants of the crucial elementary reactions were evaluated by the Rice–Ramsperger–Kassel–Marcus (RRKM) theory. The main oxidation products are a range of ring-retaining and ring-opening chemicals containing fluoranthols, fluoranthones, fluoranthenequinones, nitro-fluoranthenes, dialdehydes and epoxides. The overall rate constant of the OH addition reaction is 1.72 × 10 −11 cm 3 molecule −1 s −1 at 298 K and 1 atm. The atmospheric lifetime of Flu determined by OH radicals is about 0.69 days. This work provides a comprehensive investigation of the OH-initiated oxidation of Flu and should help to clarify its atmospheric conversion. - Highlights: • We studied a comprehensive mechanism of OH-initiated oxidation of fluoranthene. • We reported the formation pathways of fluoranthone, fluoranthenequinone and epoxide. • The rate constants of the crucial elementary steps were evaluated

  11. Mechanistic and kinetic studies on the OH-initiated atmospheric oxidation of fluoranthene

    Energy Technology Data Exchange (ETDEWEB)

    Dang, Juan; Shi, Xiangli; Zhang, Qingzhu, E-mail: zqz@sdu.edu.cn; Hu, Jingtian; Chen, Jianmin; Wang, Wenxing

    2014-08-15

    The atmospheric oxidation of polycyclic aromatic hydrocarbons (PAHs) can generate toxic derivatives which contribute to the carcinogenic potential of particulate organic matter. In this work, the mechanism of the OH-initiated atmospheric oxidation of fluoranthene (Flu) was investigated by using high-accuracy molecular orbital calculations. All of the possible oxidation pathways were discussed, and the theoretical results were compared with the available experimental observation. The rate constants of the crucial elementary reactions were evaluated by the Rice–Ramsperger–Kassel–Marcus (RRKM) theory. The main oxidation products are a range of ring-retaining and ring-opening chemicals containing fluoranthols, fluoranthones, fluoranthenequinones, nitro-fluoranthenes, dialdehydes and epoxides. The overall rate constant of the OH addition reaction is 1.72 × 10{sup −11} cm{sup 3} molecule{sup −1} s{sup −1} at 298 K and 1 atm. The atmospheric lifetime of Flu determined by OH radicals is about 0.69 days. This work provides a comprehensive investigation of the OH-initiated oxidation of Flu and should help to clarify its atmospheric conversion. - Highlights: • We studied a comprehensive mechanism of OH-initiated oxidation of fluoranthene. • We reported the formation pathways of fluoranthone, fluoranthenequinone and epoxide. • The rate constants of the crucial elementary steps were evaluated.

  12. Measuring the Distribution and Excitation of Cometary CH3OH Using ALMA

    Science.gov (United States)

    Cordiner, M. A.; Charnley, S. B.; Mumma, M. J.; Bockelée-Morvan, D.; Biver, N.; Villanueva, G.; Paganini, L.; Milam, S. N.; Remijan, A. J.; Lis, D. C.; Crovisier, J.; Boissier, J.; Kuan, Y.-J.; Coulson, I. M.

    2016-10-01

    The Atacama Large Millimeter/submillimeter Array (ALMA) was used to obtain measurements of spatially and spectrally resolved CH3OH emission from comet C/2012 K1 (PanSTARRS) on 28-29 June 2014. Detection of 12-14 emission lines of CH3OH on each day permitted the derivation of spatially-resolved rotational temperature profiles (averaged along the line of sight), for the innermost 5000 km of the coma. On each day, the CH3OH distribution was centrally peaked and approximately consistent with spherically symmetric, uniform outflow. The azimuthally-averaged CH3OH rotational temperature (T rot) as a function of sky-projected nucleocentric distance (ρ), fell by about 40 K between ρ= 0 and 2500 km on 28 June, whereas on 29 June, T rot fell by about 50 K between ρ =0 km and 1500 km. A remarkable (~50 K) rise in T rot at ρ = 1500-2500 km on 29 June was not present on 28 June. The observed variations in CH3OH rotational temperature are interpreted primarily as a result of variations in the coma kinetic temperature due to adiabatic cooling, and heating through Solar irradiation, but collisional and radiative non-LTE excitation processes also play a role.

  13. Inversion of the OH 1720-MHz line

    International Nuclear Information System (INIS)

    Elitzur, M.

    1975-01-01

    It is shown that the OH 1720-MHz line can be strongly inverted by collisions which excite the rotation states. It is also argued that radiative pumps (of any wave length) can invert strongly only the 1612-MHz line. (author)

  14. Red-shifting and blue-shifting OH groups on metal oxide surfaces - towards a unified picture.

    Science.gov (United States)

    Kebede, Getachew G; Mitev, Pavlin D; Briels, Wim J; Hermansson, Kersti

    2018-05-09

    We analyse the OH vibrational signatures of 56 structurally unique water molecules and 34 structurally unique hydroxide ions in thin water films on MgO(001) and CaO(001), using DFT-generated anharmonic potential energy surfaces. We find that the OH stretching frequencies of intact water molecules on the surface are always downshifted with respect to the gas-phase species while the OH- groups are either upshifted or downshifted. Despite these differences, the main characteristics of the frequency shifts for all three types of surface OH groups (OHw, OsH and OHf) can be accounted for by one unified expression involving the in situ electric field from the surrounding environment, and the gas-phase molecular properties of the vibrating species (H2O or OH-). The origin behind the different red- and blueshift behaviour can be traced back to the fact that the molecular dipole moment of a gas-phase water molecule increases when an OH bond is stretched, but the opposite is true for the hydroxide ion. We propose that familiarity with the relations presented here will help surface scientists in the interpretation of vibrational OH spectra for thin water films on ionic crystal surfaces.

  15. Controlled growth and thermal decomposition of well-dispersed and uniform ZnSn(OH)6 submicrocubes

    International Nuclear Information System (INIS)

    He, Qin; Zi, Junfeng; Huang, Baojun; Yan, Lingyu; Fa, Wenjun; Li, Dapeng; Zhang, Yange; Gao, Yuanhao; Zheng, Zhi

    2014-01-01

    Graphical abstract: Schematic illustration of the growth of the ZnSn(OH) 6 submicrocubes. - Highlights: • ZnSn(OH) 6 with perfect cubic shapes was formed through the chemical conversion. • We could control the morphologies of ZnSn(OH) 6 by changing reaction conditions. • Calcination of ZnSn(OH) 6 could produce different products. - Abstract: Well-dispersed and uniform ZnSn(OH) 6 submicrocubes with the average size of about 400 nm were successfully synthesized through the chemical conversion of different precipitates assisted by ultrasonic treatment and the subsequent aging process in an economical aqueous solution. The products were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TG) and Differential scanning calorimetry (DSC). The growth mechanism has been proposed and the reaction conditions were carefully investigated. It was found experimentally that ultrasound irradiation, aging process and the presence of Na 2 CO 3 in the synthetic process had an impact on the formation of the ZnSn(OH) 6 submicrocubes. Additionally, the obtained ZnSn(OH) 6 submicrocubes can be applied for the preparation of the Zn 2 SnO 4 /SnO 2 mixtures by simple calcination

  16. Improved posttraumatic acquisition of a place learning task after repeated administration of a serotonergic agonist 8-OH-DPA

    DEFF Research Database (Denmark)

    Mala, Hana; Mogensen, Jesper

    2008-01-01

    specifically to 5-HT1A receptor subtypes. The effects were evaluated in terms of functional performance on an allocentric place learning task.    Participants/Materials/Methods: 68 animals served as experimental subjects. Initially, the rats were divided into 6 experimental groups, three of which were...... was given a single dose (5mg/kg/b.w.) of 8-OH-DPAT immediately after surgery (SINGLE TREATM), and one group was treated with daily administration of 8-OH-DPAT (5mg/kg/b.w.) for the six subsequent days (the first administration taking place immediately after surgery) (REPEATED TREATM). The acquisition...... of the water maze based place learning task started on the 8th day after surgery and continued daily for the next 25 days.   Results: The results show that within the lesioned groups, the group that was subjected to repeated administration of 8-OH-DPAT (REPEAT TREATM) showed a significantly improved...

  17. Preparation of hierarchical β-Ni(OH)2 nanostructures and adsorption characterization of methyl orange dye

    Science.gov (United States)

    Jiao, Shujie; Jin, Yimin; Du, Qian; Zhu, Chunguang; Gao, Shiyong; Wang, Dongbo; Wang, Jinzhong

    2018-05-01

    The β-Ni(OH)2 nanostructures have been prepared by hydrothermal with ammonia as alkali source. The morphology of β-Ni(OH)2 evolves from hexagon sheets to flower-like hierarchical structure built up from the nanosheets as increasing the amount of ammonia. Hierarchical β-Ni(OH)2 nanostructures have strong adsorption effect on methyl orange dyes. The adsorption mechanism of β-Ni(OH)2 has been investigated, which could be expressed by pseudo-second order kinetic model with best match.

  18. Electrochemical deposition of Mg(OH)2/GO composite films for corrosion protection of magnesium alloys

    OpenAIRE

    Fengxia Wu; Jun Liang; Weixue Li

    2015-01-01

    Mg(OH)2/graphene oxide (GO) composite film was electrochemical deposited on AZ91D magnesium alloys at constant potential. The characteristics of the Mg(OH)2/GO composite film were investigated by scanning electron microscope (SEM), energy-dispersive X-ray spectrometry (EDS), X-ray diffractometer (XRD) and Raman spectroscopy. It was shown that the flaky GO randomly distributed in the composite film. Compared with the Mg(OH)2 film, the Mg(OH)2/GO composite film exhibited more uniform and compac...

  19. Electrodeposition of Ni(OH)2 reinforced polyaniline coating for corrosion protection of 304 stainless steel

    Science.gov (United States)

    Jiang, Li; Syed, Junaid Ali; Gao, Yangzhi; Lu, Hongbin; Meng, Xiangkang

    2018-05-01

    In the present paper, polyaniline (PANI) coating was electropolymerized in the presence of phosphoric acid with subsequent deposition of Ni(OH)2 particles. The Ni(OH)2 reinforced PANI coating significantly enhances the corrosion resistance of 304 stainless steel (304SS) in comparison with the pristine PANI coating. The galvanostatically deposited Ni(OH)2 particles fill the pores of the pristine PANI coating and improves the coatings hydrophobicity which decreases the diffusion of aggressive media. Importantly, the Rp values of Ni(OH)2 reinforced PANI coating is much higher than that of pristine PANI coating and the Ni(OH)2 reinforced PANI coating presents a long-term anti-corrosive ability (360 h) in 3.5 wt% NaCl solution. The prolonged corrosion protection of Ni(OH)2 reinforced PANI coating is attributed to the improved physical barrier as well as the facile formation of passive oxide film that sustain the anodic protection of the coating.

  20. Electron-impact excitation of diatomic hydride cations II: OH+ and SH+

    Science.gov (United States)

    Hamilton, James R.; Faure, Alexandre; Tennyson, Jonathan

    2018-05-01

    R-matrix calculations combined with the adiabatic-nuclei-rotation and Coulomb-Born approximations are used to compute electron-impact rotational rate coefficients for two open-shell diatomic cations of astrophysical interest: the hydoxyl and sulphanyl ions, OH+ and SH+. Hyperfine resolved rate coefficients are deduced using the infinite-order-sudden approximation. The propensity rule ΔF = Δj = ΔN = ±1 is observed, as is expected for cations with a large dipole moment. A model for OH+ excitation in the Orion Bar photon-dominated region is presented which nicely reproduces Herschel observations for an electron fraction xe = 10-4 and an OH+ column density of 3 × 1013 cm-2. Electron-impact electronic excitation cross-sections and rate coefficients for the ions are also presented.

  1. Traditional foods and 25(OH)D concentrations in a subarctic First Nations community.

    Science.gov (United States)

    Mansuri, Sudaba; Badawi, Alaa; Kayaniyil, Sheena; Cole, David E; Harris, Stewart B; Mamakeesick, Mary; Wolever, Thomas; Gittelsohn, Joel; Maguire, Jonathon L; Connelly, Philip W; Zinman, Bernard; Hanley, Anthony J

    2016-01-01

    Sub-optimal vitamin D status is common worldwide and the condition may be associated with increased risk for various chronic diseases. In particular, low vitamin D status is highly prevalent in indigenous communities in Canada, although limited data are available on the determinants of serum 25-hydroxyvitamin D (25(OH)D) concentrations in this population. The relationship between traditional food consumption and vitamin D status has not been well documented. To investigate the determinants of serum 25(OH)D status in a First Nations community in Ontario, Canada, with a focus on the role of traditional food consumption and activities. A cross-sectional analysis was conducted within the Sandy Lake Health and Diabetes Project (2003-2005). A total of 445 participants (>12 years of age) were assessed for serum 25(OH)D status, anthropometric and lifestyle variables, including traditional and non-traditional dietary practices and activities. Diet patterns were identified using factor analysis, and multivariate linear regression analysis was used to analyse the determinants of 25(OH)D concentrations. Mean serum 25(OH)D concentrations were 22.1 nmol/L (16.9, 29.9 nmol/L) in men and 20.5 nmol/L (16.0, 27.3 nmol/L) in women. Multivariate determinants of higher serum 25(OH)D included higher consumption of traditional and healthier market foods, higher wild fish consumption, male gender, spring/summer season of blood collection and more frequent physical activity. Significant negative determinants included hours of TV/day, higher BMI and higher consumption of unhealthy market foods. Traditional food consumption contributed independently to higher 25(OH)D concentrations in a First Nations community with a high prevalence of sub-optimal vitamin D status.

  2. OH Reactivity Observations during the MAPS-Seoul Campaign: Contrasts between Urban and Suburban Environments

    Science.gov (United States)

    Sanchez, D.; Jeong, D.; Blake, D. R.; Wang, M. D.; Kim, D. S.; Lee, G.; Lee, M.; Jung, J.; Ahn, J.; Cho, G.; Guenther, A. B.; Kim, S.

    2015-12-01

    Direct total OH reactivity was observed in the urban and suburban environments of Seoul, South Korea using a comparative reactivity method (CRM) during the MAPS-Seoul field campaign. In addition, CO, NOx, SO2, ozone, VOCs, aerosol, physical, and chemical parameters were also deployed. By comparing the observed total OH reactivity results with calculated OH reactivity from the trace gas observational datasets, we will evaluate our current status in constraining reactive gases in the urban and suburban environments in the East Asian megacity. Observed urban OH reactivity will be presented in the context of the ability to constrain anthropogenic reactive trace gas emissions. It will then be compared to the observed suburban results from Taehwa Research Forest (located ~ 50 km from the Seoul City Center). Our understanding of reactive trace gases in an environment of high BVOC emissions in a mildly aged anthropogenic influences will be evaluated. Using an observational constrained box model with detailed VOC oxidation schemes (e.g. MCM), we will discuss: 1) what is the amount of missing OH reactivity 2) what are the potential sources of the missing OH reactivity, and 3) what are the implications on regional air quality?

  3. Resolving the mesospheric nighttime 4.3 µm emission puzzle: comparison of the CO2(ν3) and OH(ν) emission models

    Science.gov (United States)

    Panka, Peter A.; Kutepov, Alexander A.; Kalogerakis, Konstantinos S.; Janches, Diego; Russell, James M.; Rezac, Ladislav; Feofilov, Artem G.; Mlynczak, Martin G.; Yiğit, Erdal

    2017-08-01

    In the 1970s, the mechanism of vibrational energy transfer from chemically produced OH(ν) in the nighttime mesosphere to the CO2(ν3) vibration, OH(ν) ⇒ N2(ν) ⇒ CO2(ν3), was proposed. In later studies it was shown that this "direct" mechanism for simulated nighttime 4.3 µm emissions of the mesosphere is not sufficient to explain space observations. In order to better simulate these observations, an additional enhancement is needed that would be equivalent to the production of 2.8-3 N2(1) molecules instead of one N2(1) molecule in each quenching reaction of OH(ν) + N2(0). Recently a new "indirect" channel of the OH(ν) energy transfer to N2(ν) vibrations, OH(ν) ⇒ O(1D) ⇒ N2(ν), was suggested and then confirmed in a laboratory experiment, where its rate for OH(ν = 9) + O(3P) was measured. We studied in detail the impact of the "direct" and "indirect" mechanisms on CO2(ν3) and OH(ν) vibrational level populations and emissions. We also compared our calculations with (a) the SABER/TIMED nighttime 4.3 µm CO2 and OH 1.6 and 2.0 µm limb radiances of the mesosphere-lower thermosphere (MLT) and (b) with ground- and space-based observations of OH(ν) densities in the nighttime mesosphere. We found that the new "indirect" channel provides a strong enhancement of the 4.3 µm CO2 emission, which is comparable to that obtained with the "direct" mechanism alone but assuming an efficiency that is 3 times higher. The model based on the "indirect" channel also produces OH(ν) density distributions which are in good agreement with both SABER limb OH emission observations and ground and space measurements. This is, however, not true for the model which relies on the "direct" mechanism alone. This discrepancy is caused by the lack of an efficient redistribution of the OH(ν) energy from higher vibrational levels emitting at 2.0 µm to lower levels emitting at 1.6 µm. In contrast, the new  indirect  mechanism efficiently removes at least five quanta in each

  4. Shock tube measurements of the rate constants for seven large alkanes+OH

    KAUST Repository

    Badra, Jihad

    2015-01-01

    Reaction rate constants for seven large alkanes + hydroxyl (OH) radicals were measured behind reflected shock waves using OH laser absorption. The alkanes, n-hexane, 2-methyl-pentane, 3-methyl-pentane, 2,2-dimethyl-butane, 2,3-dimethyl-butane, 2-methyl-heptane, and 4-methyl-heptane, were selected to investigate the rates of site-specific H-abstraction by OH at secondary and tertiary carbons. Hydroxyl radicals were monitored using narrow-line-width ring-dye laser absorption of the R1(5) transition of the OH spectrum near 306.7 nm. The high sensitivity of the diagnostic enabled the use of low reactant concentrations and pseudo-first-order kinetics. Rate constants were measured at temperatures ranging from 880 K to 1440 K and pressures near 1.5 atm. High-temperature measurements of the rate constants for OH + n-hexane and OH + 2,2-dimethyl-butane are in agreement with earlier studies, and the rate constants of the five other alkanes with OH, we believe, are the first direct measurements at combustion temperatures. Using these measurements and the site-specific H-abstraction measurements of Sivaramakrishnan and Michael (2009) [1,2], general expressions for three secondary and two tertiary abstraction rates were determined as follows (the subscripts indicate the number of carbon atoms bonded to the next-nearest-neighbor carbon): S20=1.58×10-11exp(-1550K/T)cm3molecule-1s-1(887-1327K)S30=2.37×10-11exp(-1850K/T)cm3molecule-1s-1(887-1327K)S21=4.5×10-12exp(-793.7K/T)cm3molecule-1s-1(833-1440K)T100=2.85×10-11exp(-1138.3K/T)cm3molecule-1s-1(878-1375K)T101=7.16×10-12exp(-993K/T)cm3molecule-1s-1(883-1362K) © 2014 The Combustion Institute.

  5. Direct Evidence for PCB Destruction in the Subtropical Troposphere by OH Radicals

    Science.gov (United States)

    Mandalakis, M.; Berresheim, H.; Stephanou, E.

    2003-04-01

    Although polychlorinated biphenyls (PCBs) production and use were banned by the mid-1970s, PCBs are ubiquitous pollutants in nearly all environmental compartments. Because of their high persistence and toxicity PCBs can pose toxic effects on animals and humans, decades after their release into the environment. It has been supported that warm temperatures at the tropical and subtropical regions of the earth favor the volatilization of PCBs, which are subsequently transported to colder areas of high latitude. This process, known as "global distillation effect", could cause an enhancement of PCB concentrations in the plant biomass and the marine mammals of Earth's polar regions. It has been experimentally established, that chemical reactions of PCBs with OH radicals might be the dominant loss processes in the atmosphere1. Nevertheless, PCBs atmospheric removal by OH radicals has never been positively demonstrated under real atmospheric conditions, mainly due to the difficulties to measure simultaneously the concentration of OH radicals and PCBs in the atmosphere. By applying elaborated sampling and analytical techniques2,3, under real atmospheric conditions, we achieved the simultaneous determination of OH radicals and PCBs congeners and demonstrated for the first time that PCB removal from the troposphere of subtropical regions is due to a large extent to reactions with OH radicals. References 1. Anderson, P. N. &Hites, R. A. OH radical reactions: The major removal pathway for polychlorinated biphenyls from the atmosphere. Environ. Sci. Technol. 30, 1756-1763 (1996). 2. Berresheim, H., Elste, T., Plass-Dülmer, C., Eisele, F. L. &Tanner, D. J. Chemical ionization mass spectrometer for long-term measurements of atmospheric OH and H2SO4. Int. J. Mass Spectrom. 202, 91-109 (2000). 3. Mandalakis, M., M. Tsapakis, and E.G. Stephanou, Optimization and application of high-resolution gas chromatography with ion trap tandem mass spectrometry to the determination of

  6. Atmospheric degradation of 2- nitrobenzaldehyde: Photolysis and reaction with OH radicals

    Science.gov (United States)

    Bouya, H.; Al Rashidi, M.; Roth, E.; Salghi, R.; Chakir, A.

    2017-12-01

    This work presents an experimental study of the gas phase kinetics of 2-nitrobenzaldehyde (2-NBA) photolysis and oxidation by OH radicals. The experiments were carried out in an atmospheric simulation chamber coupled to an FTIR spectrometer and CG/MS. The UV spectra of 2-NBA were also measured and the experimentally determined absorption cross sections were used to estimate the atmospheric photo-dissociation constant of 2-NBA with a global quantum yield of 0.5. The obtained results indicate that 2-NBA is a highly photolysable. A mechanism of 2-NBA photolysis was proposed based on the identification of photolysis degradation products. The kinetics of oxidation of 2-NBA by OH radicals was investigated over the temperature range 308-352 K. The obtained rate coefficients exhibits slight negative temperature dependence and the Arrhenius expression obtained is as follows: kOH+2-NBA(T)= (7.00 ± 3.40) × 10-12exp (577 ± 156/T) cm3 molecule-1 s-1. The calculated rate coefficients lead to tropospheric lifetimes of 2-NBA that are in the order of a few minutes, relative to photolysis, or a few hours, relative to oxidation by OH radicals.

  7. Excessive fructose intake causes 1,25-(OH)2D3-dependent inhibition of intestinal and renal calcium transport in growing rats

    Science.gov (United States)

    Douard, Veronique; Sabbagh, Yves; Lee, Jacklyn; Patel, Chirag; Kemp, Francis W.; Bogden, John D.; Lin, Sheldon

    2013-01-01

    We recently discovered that chronic high fructose intake by lactating rats prevented adaptive increases in rates of active intestinal Ca2+ transport and in levels of 1,25-(OH)2D3, the active form of vitamin D. Since sufficient Ca2+ absorption is essential for skeletal growth, our discovery may explain findings that excessive consumption of sweeteners compromises bone integrity in children. We tested the hypothesis that 1,25-(OH)2D3 mediates the inhibitory effect of excessive fructose intake on active Ca2+ transport. First, compared with those fed glucose or starch, growing rats fed fructose for 4 wk had a marked reduction in intestinal Ca2+ transport rate as well as in expression of intestinal and renal Ca2+ transporters that was tightly associated with decreases in circulating levels of 1,25-(OH)2D3, bone length, and total bone ash weight but not with serum parathyroid hormone (PTH). Dietary fructose increased the expression of 24-hydroxylase (CYP24A1) and decreased that of 1α-hydroxylase (CYP27B1), suggesting that fructose might enhance the renal catabolism and impair the synthesis, respectively, of 1,25-(OH)2D3. Serum FGF23, which is secreted by osteocytes and inhibits CYP27B1 expression, was upregulated, suggesting a potential role of bone in mediating the fructose effects on 1,25-(OH)2D3 synthesis. Second, 1,25-(OH)2D3 treatment rescued the fructose effect and normalized intestinal and renal Ca2+ transporter expression. The mechanism underlying the deleterious effect of excessive fructose intake on intestinal and renal Ca2+ transporters is a reduction in serum levels of 1,25-(OH)2D3. This finding is significant because of the large amounts of fructose now consumed by Americans increasingly vulnerable to Ca2+ and vitamin D deficiency. PMID:23571713

  8. Evidence of an Unidentified Extracellular Heat-Stable Factor Produced by Lysobacter enzymogenes (OH11) that Degrade Fusarium graminearum PH1 Hyphae.

    Science.gov (United States)

    Odhiambo, Benard Omondi; Xu, Gaoge; Qian, Guoliang; Liu, Fengquan

    2017-04-01

    Lysobacter enzymogenes OH11 produces heat-stable antifungal factor (HSAF) and lytic enzymes possessing antifungal activity. This study bio-prospected for other potential antifungal factors besides those above. The cells and extracellular metabolites of L. enzymogenes OH11 and the mutants ΔchiA, ΔchiB, ΔchiC, Δclp, Δpks, and ΔpilA were examined for antifungal activity against Fusarium graminearum PH1, the causal agent of Fusarium head blight (FHB). Results evidenced that OH11 produces an unidentified extracellular heat-stable degrading metabolite (HSDM) that exhibit degrading activity on F. graminearum PH1 chitinous hyphae. Interestingly, both heat-treated and non-heat-treated extracellular metabolites of OH11 mutants exhibited hyphae-degrading activity against F. graminearum PH1. Enzyme activity detection of heat-treated metabolites ruled out the possibility of enzyme degradation activity. Remarkably, the PKS-NRPS-deficient mutant Δpks cannot produce HSAF or analogues, yet its metabolites exhibited hyphae-degrading activity. HPLC analysis confirmed no HSAF production by Δpks. Δclp lacks hyphae-degrading ability. Therefore, clp regulates HSDM and extracellular lytic enzymes production in L. enzymogenes OH11. ΔpilA had impaired surface cell motility and significantly reduced antagonistic properties. ΔchiA, ΔchiB, and ΔchiC retained hyphae-degrading ability, despite having reduced abilities to produce chitinase enzymes. Ultimately, L. enzymogenes OH11 can produce other unidentified HSDM independent of the PKS-NRPS genes. This suggests HSAF and lytic enzymes production are a fraction of the antifungal mechanisms in OH11. Characterization of HSDM, determination of its biosynthetic gene cluster and understanding its mode of action will provide new leads in the search for effective drugs for FHB management.

  9. Preparation of binder-free porous ultrathin Ni(OH)2 nanoleafs using ZnO as pore forming agent displaying both high mass loading and excellent electrochemical energy storage performance

    International Nuclear Information System (INIS)

    Xu, Panpan; Miao, Chenxu; Cheng, Kui; Ye, Ke; Yin, Jinling; Cao, Dianxue; Wang, Guiling; Zhang, Xianfa

    2016-01-01

    Highlights: • Porous Ni(OH) 2 nanoleaf is prepared by using ZnO as pore forming agent. • The mass loading of active material on binder-free Ni(OH) 2 /NF electrode is as high as 10 mg. • The porous Ni(OH) 2 /NF electrode displays high specific capacitance of 1142C g −1 . - Abstract: Ni(OH) 2 has been reported widely as one of the most promising supercapactior electrode materials due to its high specific capacitance, yet which were only based on low mass loading. Thus, it is desirable to promote supercapacitor performance for high mass loading Ni(OH) 2 through optimizing microstructure. In this work, we first prepared crossed ultrathin Ni(OH) 2 /ZnO nanoleafs directly grown on nickel foam via hydrothermal method, and then we produced pores on the nanoleafs by dissolving ZnO in alkaline solution. Definitely, this unique structure design for high mass loading binder-free Ni(OH) 2 electrode could benefit the penetration of electrolyte and the transportation of electrons, efficiently improving the supercapacitor performance. The obtained porous Ni(OH) 2 /NF electrode exhibits a mass specific capacity of 1142C g −1 based on 10 mg active materials, equating to a areal specific capaciy of 11.4C cm −2 , and pleasant cycling stability with retention of 85% of initial capacity after 10000 charge-discharge cycles. The fabricated asymmetric device shows a high energy density of 42 Wh kg −1 (4.73 mWh cm −3 ) at power density of 105 W kg −1 (17 mW cm −3 ). These results demonstrate the optimized structure makes the high mass loading binder-free Ni(OH) 2 /NF electrode could also display excellent supercapacitor performance.

  10. Antiferromagnetic Coupling in the Polynuclear Compound [Cu(II) (Allopurinolate) (OH-)] n

    Science.gov (United States)

    Acevedo-Chávez, Rodolfo; Costas, María. Eugenia; Escudero-Derat, Roberto

    1994-11-01

    Synthetic, spectral, and magnetic studies of the Cu(II) polynuclear coordination compound [Cu(HL(OH-)]n with bridging OH- and HL (allopurinolate; C5H3N4O-) ligands are reported. The compound is obtained from aqueous media (at several pH values and from CI-, Br-, NO-3, SO2-4, ClO-4, and CH3CO-2 Cu(II) salts), from DMSO at ca. 70°C using several of the above salts, and under refluxing methanol employing Cu(SO4) or Cu(CH3CO2)2. The results suggest that the compound [Cu(HL)(OH-)]n has a polynuclear form in which the bridging allopurinolate is coordinated through the N(1) and N(2) atoms of the pyrazolic moiety. All attempts to grow crystals suitable for X-ray studies were unsuccessful, and an amorphous compound was always obtained. Magnetic studies show the existence of a strong antiferromagnetic coupling, which may be associated with a favorable structural arrangement between the metallic centers and the bridging ligands. This magnetic behavior is remarkable for a Cu(II) polynuclear coordination compound. Spectral and magnetic results together with the coordination modes of the bridging groups let us postulate as a possible arrangement a cyclic polynuclear structure presenting the allopurinolate and OH- bridging ligands in a mutually trans configuration. This work is the first EPR spectral and magnetic study reported for a coordination compound with the allopurinol heterocycle as a ligand and, thus for the first example of a polynuclear coordination compound combining allopurinolate and OH- as bridging groups.

  11. Determinants of 25(OH)D sufficiency in obese minority children: selecting outcome measures and analytic approaches.

    Science.gov (United States)

    Zhou, Ping; Schechter, Clyde; Cai, Ziyong; Markowitz, Morri

    2011-06-01

    To highlight complexities in defining vitamin D sufficiency in children. Serum 25-(OH) vitamin D [25(OH)D] levels from 140 healthy obese children age 6 to 21 years living in the inner city were compared with multiple health outcome measures, including bone biomarkers and cardiovascular risk factors. Several statistical analytic approaches were used, including Pearson correlation, analysis of covariance (ANCOVA), and "hockey stick" regression modeling. Potential threshold levels for vitamin D sufficiency varied by outcome variable and analytic approach. Only systolic blood pressure (SBP) was significantly correlated with 25(OH)D (r = -0.261; P = .038). ANCOVA revealed that SBP and triglyceride levels were statistically significant in the test groups [25(OH)D 25 ng/mL]. ANCOVA also showed that only children with severe vitamin D deficiency [25(OH)D model regression analyses found evidence of a threshold level in SBP, with a 25(OH)D breakpoint of 27 ng/mL, along with a 25(OH)D breakpoint of 18 ng/mL for triglycerides, but no relationship between 25(OH)D and parathyroid hormone. Defining vitamin D sufficiency should take into account different vitamin D-related health outcome measures and analytic methodologies. Copyright © 2011 Mosby, Inc. All rights reserved.

  12. Analysis of present day and future OH and methane lifetime in the ACCMIP simulations

    Directory of Open Access Journals (Sweden)

    A. Voulgarakis

    2013-03-01

    Full Text Available Results from simulations performed for the Atmospheric Chemistry and Climate Modeling Intercomparison Project (ACCMIP are analysed to examine how OH and methane lifetime may change from present day to the future, under different climate and emissions scenarios. Present day (2000 mean tropospheric chemical lifetime derived from the ACCMIP multi-model mean is 9.8 ± 1.6 yr (9.3 ± 0.9 yr when only including selected models, lower than a recent observationally-based estimate, but with a similar range to previous multi-model estimates. Future model projections are based on the four Representative Concentration Pathways (RCPs, and the results also exhibit a large range. Decreases in global methane lifetime of 4.5 ± 9.1% are simulated for the scenario with lowest radiative forcing by 2100 (RCP 2.6, while increases of 8.5 ± 10.4% are simulated for the scenario with highest radiative forcing (RCP 8.5. In this scenario, the key driver of the evolution of OH and methane lifetime is methane itself, since its concentration more than doubles by 2100 and it consumes much of the OH that exists in the troposphere. Stratospheric ozone recovery, which drives tropospheric OH decreases through photolysis modifications, also plays a partial role. In the other scenarios, where methane changes are less drastic, the interplay between various competing drivers leads to smaller and more diverse OH and methane lifetime responses, which are difficult to attribute. For all scenarios, regional OH changes are even more variable, with the most robust feature being the large decreases over the remote oceans in RCP8.5. Through a regression analysis, we suggest that differences in emissions of non-methane volatile organic compounds and in the simulation of photolysis rates may be the main factors causing the differences in simulated present day OH and methane lifetime. Diversity in predicted changes between present day and future OH was found to be associated more strongly with

  13. Graphene-Wrapped Ni(OH)2 Hollow Spheres as Novel Electrode Material for Supercapacitors.

    Science.gov (United States)

    Sun, Jinfeng; Wang, Jinqing; Li, Zhangpeng; Ou, Junfei; Niu, Lengyuan; Wang, Honggang; Yang, Shengrong

    2015-09-01

    Graphene-wrapped Ni(OH)2 hollow spheres were prepared via electrostatic interaction between poly(diallyldimethylammonium chloride) (PDDA) modified Ni(OH)2 and graphene oxide (GO) in an aqueous dispersion, followed by the reduction of GO. Morphological and structural analysis by field-emission scanning electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis confirmed the successful coating of graphene on Ni(OH)2 hollow spheres with a content of 3.8 wt%. And then its application as electrode material for supercapacitor has been investigated by cyclic voltammetry (CV) and galvanostatic charge-discharge tests. Results show that the sample displays a high capacitance of 1368 F g(-1) at a current density of 1 A g(-1), much better than that of pure Ni(OH)2, illustrating that such composite is a promising candidate as electrode material for supercapacitors.

  14. Direct observation of an isopolyhalomethane O-H insertion reaction with water: Picosecond time-resolved resonance Raman (ps-TR3) study of the isobromoform reaction with water to produce a CHBr2OH product

    International Nuclear Information System (INIS)

    Kwok, W.M.; Zhao Cunyuan; Li Yunliang; Guan Xiangguo; Phillips, David Lee

    2004-01-01

    Picosecond time-resolved resonance Raman (ps-TR 3 ) spectroscopy was used to obtain the first definitive spectroscopic observation of an isopolyhalomethane O-H insertion reaction with water. The ps-TR 3 spectra show that isobromoform is produced within several picoseconds after photolysis of CHBr 3 and then reacts on the hundreds of picosecond time scale with water to produce a CHBr 2 OH reaction product. Photolysis of low concentrations of bromoform in aqueous solution resulted in noticeable formation of HBr strong acid. Ab initio calculations show that isobromoform can react with water to produce a CHBr 2 (OH) O-H insertion reaction product and a HBr leaving group. This is consistent with both the ps-TR 3 experiments that observe the reaction of isobromoform with water to form a CHBr 2 (OH) product and photolysis experiments that show HBr acid formation. We briefly discuss the implications of these results for the phase dependent behavior of polyhalomethane photochemistry in the gas phase versus water solvated environments

  15. Preparation of Ni(OH)2-graphene sheet-carbon nanotube composite as electrode material for supercapacitors

    International Nuclear Information System (INIS)

    Liu, Y.F.; Yuan, G.H.; Jiang, Z.H.; Yao, Z.P.; Yue, M.

    2015-01-01

    Highlights: • CNT is introduced into graphene to prevent restacking by solvothermal reaction. • Ethanol as a low cost and green solvent is used in solvothermal reaction. • Ni(OH) 2 nanosheets were chemically precipitated into GS-CNT to increase the capacitance. - Abstract: Ni(OH) 2 -graphene sheet-carbon nanotube composite was prepared for supercapacitance materials through a simple two-step process involving solvothermal synthesis of graphene sheet-carbon nanotube composite in ethanol and chemical precipitation of Ni(OH) 2 . According to N 2 adsorption/desorption analysis, the Brunauer–Emmett–Teller surface area of graphene sheet-carbon nanotube composite (109.07 m 2 g −1 ) was larger than that of pure graphene sheets (32.06 m 2 g −1 ), indicating that the added carbon nanotubes (15 wt.%) could prevent graphene sheets from restacking in the solvothermal reaction. The results of field emission scanning electron microscopy and transmission electron microscopy showed that Ni(OH) 2 nanosheets were uniformly loaded into the three-dimensional interconnected network of graphene sheet-carbon nanotube composite. The microstructure enhanced the rate capability and utilization of Ni(OH) 2 . The specific capacitance of Ni(OH) 2 -graphene sheet-carbon nanotube composite was 1170.38 F g −1 at a current density of 0.2 A g −1 in the 6 mol L −1 KOH solution, higher than those provided by pure Ni(OH) 2 (953.67 Fg −1 ) and graphene sheets (178.25 F g −1 ). After 20 cycles at each current density (0.2, 0.4, 0.6, 0.8, 1.0 and 1.2 A g −1 ), the capacitance of Ni(OH) 2 -graphene sheet-carbon nanotube composite decreased 26.96% of initial capacitance compared to 74.52% for pure Ni(OH) 2

  16. Synthesis and characterization of β-Ni(OH)2 up grown nanoflakes by SILAR method

    International Nuclear Information System (INIS)

    Kulkarni, S.B.; Jamadade, V.S.; Dhawale, D.S.; Lokhande, C.D.

    2009-01-01

    In this paper we report a 'bottom up' approach to synthesize β-Ni(OH) 2 nanoflakes using novel successive ionic layer adsorption and reaction (SILAR) method. Ni(OH) 2 thin films have been deposited on glass substrate using aqueous alkaline nickel chloride as nickel ion source and double distilled water maintained at 353 K temperature as hydroxyl ion source. The structural, surface morphological, optical and electrical properties of films are examined. The nanocrystallinity and β-phase of Ni(OH) 2 are confirmed by X-ray diffraction and FT-IR studies. Scanning electron microscope study revealed microporous and random distribution of well up grown interlocked nanoflakes. Optical absorption studies show wide optical band gap of 3.26 eV for β-Ni(OH) 2 . The electrical properties revealed that β-Ni(OH) 2 has negative temperature coefficient of resistance with p-type semiconducting behaviour. The electrochemical property studied by cyclic voltametry in 2 M KOH electrolyte solution revealed pseudo capacitive behaviour, when β-Ni(OH) 2 thin film employed as working electrode in three electrode electrochemical cell with platinum as counter electrode and saturated calomel as reference electrode. The specific capacitance of 350 F g -1 is obtained with nanoflake like morphology.

  17. Volatility and lifetime against OH heterogeneous reaction of ambient isoprene-epoxydiols-derived secondary organic aerosol (IEPOX-SOA)

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Weiwei; Palm, Brett B.; Day, Douglas A.; Campuzano-Jost, Pedro; Krechmer, Jordan E.; Peng, Zhe; de Sá, Suzane S.; Martin, Scot T.; Alexander, M. Lizabeth; Baumann, Karsten; Hacker, Lina; Kiendler-Scharr, Astrid; Koss, Abigail R.; de Gouw, Joost A.; Goldstein, Allen H.; Seco, Roger; Sjostedt, Steven J.; Park, Jeong-Hoo; Guenther, Alex B.; Kim, Saewung; Canonaco, Francesco; Prévôt, André S. H.; Brune, William H.; Jimenez, Jose L.

    2016-01-01

    Isoprene-epoxydiols-derived secondary organic aerosol (IEPOX-SOA) can contribute substantially to organic aerosol (OA) concentrations in forested areas under low NO conditions, hence significantly influencing the regional and global OA budgets, accounting, for example, for 16–36 % of the submicron OA in the southeastern United States (SE US) summer. Particle evaporation measurements from a thermodenuder show that the volatility of ambient IEPOX-SOA is lower than that of bulk OA and also much lower than that of known monomer IEPOX-SOA tracer species, indicating that IEPOX-SOA likely exists mostly as oligomers in the aerosol phase. The OH aging process of ambient IEPOX-SOA was investigated with an oxidation flow reactor (OFR). New IEPOX-SOA formation in the reactor was negligible, as the OFR does not accelerate processes such as aerosol uptake and reactions that do not scale with OH. Simulation results indicate that adding ~100 µg m-3 of pure H2SO4 to the ambient air allows IEPOX-SOA to be efficiently formed in the reactor. The heterogeneous reaction rate coefficient of ambient IEPOX-SOA with OH radical (kOH) was estimated as 4.0 ± 2.0 ×10-13 cm3 molec-1 s-1, which is equivalent to more than a 2-week lifetime. A similar kOH was found for measurements of OH oxidation of ambient Amazon forest air in an OFR. At higher OH exposures in the reactor (> 1 × 1012 molec cm-3 s), the mass loss of IEPOX-SOA due to heterogeneous reaction was mainly due to revolatilization of fragmented reaction products. We report, for the first time, OH reactive uptake coefficients (γOH = 0.59±0.33 in SE US and γOH = 0.68±0.38 in Amazon) for SOA under ambient conditions. A relative humidity dependence of kOH and γOH was observed, consistent with surface-area-limited OH uptake

  18. Pb4(OH)4(BrO3)3(NO3): An Example of SHG Crystal in Metal Bromates Containing π-Conjugated Planar Triangle.

    Science.gov (United States)

    Kong, Fang; Hu, Chun-Li; Liang, Ming-Li; Mao, Jiang-Gao

    2016-01-19

    The first example of SHG crystal in the metal bromates containing π-conjugated planar triangle systems, namely, Pb4(OH)4(BrO3)3(NO3), was successfully synthesized via the hydrothermal method. Furthermore, a single crystal of centrosymmetric Pb8O(OH)6(BrO3)6(NO3)2·H2O was also obtained. Both compounds contain similar [Pb4(OH)4] cubane-like tetranuclear clusters, but they display different one-dimensional (1D) chain structures. Pb4(OH)4(BrO3)3(NO3) features a zigzag [Pb4(OH)4(BrO3)3](+) 1D chain, while Pb8O(OH)6(BrO3)6(NO3)2·H2O is composed of two different orthogonal chains: the linear [Pb4(OH)4(BrO3)2](2+) 1D chain along the b-axis and the zigzag [Pb4O2(OH)2(BrO3)4](2-) 1D chain along the a-axis. The NO3 planar triangles of the compounds are all isolated and located in the spaces of the structures. Pb4(OH)4(BrO3)3(NO3) exhibits the first example of SHG crystal in the metal bromates with π-conjugated planar triangle. The second-harmonic generation (SHG) efficiency of Pb4(OH)4(BrO3)3(NO3) is approximately equal to that of KDP and it is phase-matchable. Dipole moment and theory calculations indicate that BrO3, NO3, and PbO4 groups are the origin of its SHG efficiency, although some of the contributions cancel each other out.

  19. Resolving the mesospheric nighttime 4.3 µm emission puzzle: comparison of the CO2(ν3 and OH(ν emission models

    Directory of Open Access Journals (Sweden)

    P. A. Panka

    2017-08-01

    Full Text Available In the 1970s, the mechanism of vibrational energy transfer from chemically produced OH(ν in the nighttime mesosphere to the CO2(ν3 vibration, OH(ν ⇒ N2(ν ⇒ CO2(ν3, was proposed. In later studies it was shown that this "direct" mechanism for simulated nighttime 4.3 µm emissions of the mesosphere is not sufficient to explain space observations. In order to better simulate these observations, an additional enhancement is needed that would be equivalent to the production of 2.8–3 N2(1 molecules instead of one N2(1 molecule in each quenching reaction of OH(ν + N2(0. Recently a new "indirect" channel of the OH(ν energy transfer to N2(ν vibrations, OH(ν ⇒ O(1D ⇒ N2(ν, was suggested and then confirmed in a laboratory experiment, where its rate for OH(ν = 9 + O(3P was measured. We studied in detail the impact of the "direct" and "indirect" mechanisms on CO2(ν3 and OH(ν vibrational level populations and emissions. We also compared our calculations with (a the SABER/TIMED nighttime 4.3 µm CO2 and OH 1.6 and 2.0 µm limb radiances of the mesosphere–lower thermosphere (MLT and (b with ground- and space-based observations of OH(ν densities in the nighttime mesosphere. We found that the new "indirect" channel provides a strong enhancement of the 4.3 µm CO2 emission, which is comparable to that obtained with the "direct" mechanism alone but assuming an efficiency that is 3 times higher. The model based on the "indirect" channel also produces OH(ν density distributions which are in good agreement with both SABER limb OH emission observations and ground and space measurements. This is, however, not true for the model which relies on the "direct" mechanism alone. This discrepancy is caused by the lack of an efficient redistribution of the OH(ν energy from higher vibrational levels emitting at 2.0 µm to lower levels emitting at 1.6 µm. In contrast, the new  indirect  mechanism

  20. Separation of compounds with multiple -OH groups from dilute aqueous solutions via complexation with organoboronate

    Energy Technology Data Exchange (ETDEWEB)

    Chow, Tina Kuo Fung [Univ. of California, Berkeley, CA (United States)

    1992-05-01

    The complexing extractant agent investigated in this work is 3-nitrophenylboronic acid (NPBA) in its anionic form (NPB). NPBA and Aliquat 336 (quaternary amine) is dissolved in 2-ethyl-l-hexanol, and the extractant is contacted with aq. NaOH. Solutes investigated were 1,2-propanediol, glycerol, fructose, sorbitol and lactic acid. Batch extraction experiments were performed at 25°C. Partition coefficients, distribution ratios and loadings are reported for varying concentrations of solute and NPB. All solutes complexed with NPB-, with all complexes containing only one NPB- per complex. The 1:1 complexation constants for the solutes glycerol, fructose and sorbitol follow trends similar to complexation with B(OH)4- (aq.), i.e. the complexation constants increase with increasing number of -OH groups available for complexation. Assumption of 1:1 complex is not valid for 1, 2-propanediol, which showed overloading (more than one mole of solute complexed to one mole NPB-) at higher concentrations. The -OH group on the NPB- which is left uncomplexed after one solute molecule had bound to the other two -OH groups may be responsible for the overloading. Overloading is also observed in extraction of tactic acid, but through a different mechanism. It was found that TOMA+ can extract lactic acid to an extent comparable to the uptake of lactic acid by NPB-. The complexation is probably through formation of an acid-base ion pair. Losses of NPBA into the aqueous phase could lead to problems, poor economics in industrial separation processes. One way of overcoming this problem would be to incorporate the NPBA onto a solid support.

  1. Di-µ-hydroxo Bridge Cleavage Reactions between [Co(nta)(µ-OH)] 2 ...

    African Journals Online (AJOL)

    NJD

    2004-04-22

    Apr 22, 2004 ... subsequent rate determining steps to form presumably a ligand-substituted, mono-bridged complex, [(nta)(OH)Co-µ-. OH-Co(nta)(L)]2– (L = py/dmap). The latter decomposes rapidly to form the products. The preferred pathway for these bridge cleavage seemed to be the reaction of the mono-µ-hydroxo-.

  2. Oh What a Tangled Biofilm Web Bacteria Weave

    Science.gov (United States)

    ... Home Page Oh What a Tangled Biofilm Web Bacteria Weave By Elia Ben-Ari Posted May 1, ... a suitable surface, some water and nutrients, and bacteria will likely put down stakes and form biofilms. ...

  3. Thermodynamic properties of a layered S = 7/2 Heisenberg magnet Gd(OH)CO3

    Science.gov (United States)

    Orendac, Martin; Ulicny, Martin; Cizmar, Erik; Orendacova, Alzbeta; Chen, Yan-Cong; Meng, Zhao-Sha; Tong, Ming-Liang

    2015-03-01

    Thermodynamic quantities and ESR spectra of Gd(OH)CO3 (I) are reported. The material may be considered to consist of weakly coupled layers with potentially triangular arrangement of exchange paths within each layer. Different bridging groups and distances among Gd3+ ions may be responsible for spatial anisotropy of magnetic coupling. Preliminary analysis of magnetic susceptibility using Curie-Weiss law yielded θ = -1.05 K indicating weak antiferromagnetic coupling and consequently, spin frustration in (I). More detailed simultaneous analysis of specific heat, susceptibility and magnetization studied down to nominally 0.45 K revealed non-negligible role of single-ion anisotropy. Using the model of weakly interacting S =7/2 trimers, the gross features of measured data may be explained while assuming single-ion anisotropy D /kB ~ 0.6 K and effective intratrimer magnetic coupling | J /kB | ~0.3 K. The obtained D value reasonably reproduces the position and shape of ESR line. The performed analysis suggests that magnetism in (I) is governed predominantly by crystal field effects and frustration plays a minor role. Supported by ITMS26220120005 and VEGA 1/0143/13.

  4. Roberts 22: a bipolar nebula with OH emission

    International Nuclear Information System (INIS)

    Allen, D.A.; Hyland, A.R.; Caswell, J.L.

    1980-01-01

    Roberts 22 is a bipolar reflection nebula illuminated by a hidden A2 Ie star. Most of its energy is radiated at infrared wavelengths. It also shows strong OH maser emission (OH 284.18 - 0.79) on the 1612 and 1665 MHz transitions, generally similar to the masers associated with M stars having infrared excesses. But the system contains no late-type star. This remarkable assemblage of attributes makes Roberts 22 unique; however, it is probably a key member of the newly-recognized population of bipolar nebulae. From an analysis of the properties of Roberts 22 some published interpretations of other bipolar nebulae are questioned, in particular the derivation of spectral types for their underlying stars by the assumption of photo-ionization of the gas, and their evolutionary description as proto-planetary nebulae. (author)

  5. Chemical synthesis of flower-like hybrid Cu(OH)2/CuO electrode: Application of polyvinyl alcohol and triton X-100 to enhance supercapacitor performance.

    Science.gov (United States)

    Shinde, S K; Fulari, V J; Kim, D-Y; Maile, N C; Koli, R R; Dhaygude, H D; Ghodake, G S

    2017-08-01

    In this research article, we report hybrid nanomaterials of copper hydroxide/copper oxide (Cu(OH) 2 /CuO). A thin films were prepared by using a facile and cost-effective successive ionic layer adsorption and reaction (SILAR) method. As-synthesized and hybrid Cu(OH) 2 /CuO with two different surfactants polyvinyl alcohol (PVA) and triton-X 100 (TRX-100) was prepared having distinct morphological, structural, and supercapacitor properties. The surface of the thin film samples were examined by scanning electron microscopy (SEM). A nanoflower-like morphology of the Cu(OH) 2 /CuO nanostructures arranged vertically was evidenced on the stainless steel substrate. The surface was well covered by nanoflake-like morphology and formed a uniform Cu(OH) 2 /CuO nanostructures after treating with surfactants. X-ray diffraction patterns were used to confirm the hybrid phase of Cu(OH) 2 /CuO materials. The electrochemical properties of the pristine Cu(OH) 2 /CuO, PVA:Cu(OH) 2 /CuO, TRX-100:Cu(OH) 2 /CuO films were observed by cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy technique. The electrochemical examination reveals that the Cu(OH) 2 /CuO electrode has excellent specific capacitance, 292, 533, and 443Fg -1 with pristine, PVA, and TRX-100, respectively in 1M Na 2 SO 4 electrolyte solution. The cyclic voltammograms (CV) of Cu(OH) 2 /CuO electrode shows positive role of the PVA and TRX-100 to enhance supercapacitor performance. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Measurement of OH radical density in DBD-enhanced premixed burner flame by laser-induced fluorescence

    Science.gov (United States)

    Zaima, Kazunori; Sasaki, Koichi

    2013-09-01

    We examined OH density in DBD-enhanced premixed burner flame by laser-induced fluorescence (LIF). We ignited a premixed flame with CH4 /O2 / Ar mixture using a burner which worked as the ground electrode. The upper part of the flame was covered with a quartz tube, and we attached an aluminum electrode on the outside of the quartz tube. DBD inside the quartz tube was obtained between the aluminum electrode and the burner nozzle. The planar beam from a pulsed tunable laser excited OH in X2 Π (v'' = 0) to A2Σ+ (v' = 0) , and we captured two-dimensional distribution of the LIF intensity using an ICCD camera. We employed three pump lines of Q1(J=4, 8 and 10), and the rotational temperature of OH(X) was deduced from the ratio of the LIF intensities. The total density of OH was obtained from the LIF intensities and the rotational temperature. A principal experimental result was that no remarkable increase was observed in the OH density by the superposition of DBD. The correlation between the pulsed discharge current and the temporal variation of the OH density was not clear, suggesting that the oscillation of the OH density with a small amplitude is related to the transittion time constant between equilibrium and nonequilibrium combustion chemistries.

  7. Vitamin D metabolites in captivity? Should we measure free or total 25(OH)D to assess vitamin D status?

    Science.gov (United States)

    Bikle, Daniel; Bouillon, Roger; Thadhani, Ravi; Schoenmakers, Inez

    2017-10-01

    There is general consensus that serum 25(OH)D is the best biochemical marker for nutritional vitamin D status. Whether free 25(OH)D would be a better marker than total 25(OH)D is so far unclear. Free 25(OH)D can either be calculated based on the measurement of the serum concentrations of total 25(OH)D, vitamin D-binding protein (DBP), albumin, and the affinity between 25(OH)D and its binding proteins in physiological situations. Free 25(OH)D can also be measured directly by equilibrium dialysis, ultrafitration or immunoassays. During the vitamin D workshop held in Boston in March 2016, a debate was organized about the measurements and clinical value of free 25(OH)D, and this debate is summarized in the present manuscript. Overall there is consensus that most cells apart from the renal tubular cells are exposed to free rather than to total 25(OH)D. Therefore free 25(OH)D may be highly relevant for the local production and action of 1,25(OH) 2 D. During the debate it became clear that there is a need for standardization of measurements of serum DBP and of direct measurements of free 25(OH)D. There seems to be very limited genetic or racial differences in DBP concentrations or (probably) in the affinity of DBP for its major ligands. Therefore, free 25(OH)D is strongly correlated to total 25(OH)D in most normal populations. Appropriate studies are needed to define the clinical implications of free rather than total 25(OH)D in normal subjects and in disease states. Special attention is needed for such studies in cases of abnormal DBP concentrations or when one could expect changes in its affinity for its ligands. Copyright © 2017. Published by Elsevier Ltd.

  8. High-performance cobalt carbonate hydroxide nano-dot/NiCo(CO3)(OH)2 electrode for asymmetric supercapacitors

    Science.gov (United States)

    Lee, Damin; Xia, Qi Xun; Yun, Je Moon; Kim, Kwang Ho

    2018-03-01

    Binder-free mesoporous NiCo(CO3)(OH)2 nanowire arrays were grown using a facile hydrothermal technique. The Co2(CO3)(OH)2 in NiCo(CO3)(OH)2 nanowire arrays was well-decorated as nano-dot scale (a few nanometer). In addition, increasing cobalt content in nickel compound matrix, NiCo(CO3)(OH)2 nanowire arrays were separately uniformly grown without agglomeration on Ni foam, providing a high specific surface area to help electrolyte access and ion transfer. The enticing composition and morphology of the NiCo(CO3)(OH)2 nanowire exhibit a superior specific capacity of 1288.2 mAh g-1 at a current density of 3 A g-1 and excellent cycling stability with the capacity retention of 80.7% after 10,000 cycles. Furthermore, an asymmetric supercapacitor composed of the NiCo(CO3)(OH)2 composite as a positive electrode and the graphene as a negative electrode presented a high energy density of 35.5 W h kg-1 at a power density of 2555.6 W kg-1 and satisfactory cycling stability with 71.3% capacity retention after 10,000 cycles. The great combination of the active nano-dot Co2(CO3)(OH)2 and the individually grown NiCo(CO3)(OH)2 nanowires made it a promising electrode material for asymmetric supercapacitors. A well-developed nanoarchitecture of the nano-dot Co2(CO3)(OH)2 decorated NiCo(CO3)(OH)2 composite could pave the way for an excellent electrode design for high-performance supercapacitors.

  9. Vitamin D and 1,25(OH2D Regulation of T cells

    Directory of Open Access Journals (Sweden)

    Margherita T. Cantorna

    2015-04-01

    Full Text Available Vitamin D is a direct and indirect regulator of T cells. The mechanisms by which vitamin D directly regulates T cells are reviewed and new primary data on the effects of 1,25 dihydroxyvitamin D (1,25(OH2D on human invariant natural killer (iNKT cells is presented. The in vivo effects of vitamin D on murine T cells include inhibition of T cell proliferation, inhibition of IFN-γ, IL-17 and induction of IL-4. Experiments in mice demonstrate that the effectiveness of 1,25(OH2D requires NKT cells, IL-10, the IL-10R and IL-4. Comparisons of mouse and human T cells show that 1,25(OH2D inhibits IL-17 and IFN-γ, and induces T regulatory cells and IL-4. IL-4 was induced by 1,25(OH2D in mouse and human iNKT cells. Activation for 72h was required for optimal expression of the vitamin D receptor (VDR in human and mouse T and iNKT cells. In addition, T cells are potential autocrine sources of 1,25(OH2D but again only 48–72h after activation. Together the data support the late effects of vitamin D on diseases like inflammatory bowel disease and multiple sclerosis where reducing IL-17 and IFN-γ, while inducing IL-4 and IL-10, would be beneficial.

  10. Measurements of HOx radicals and the total OH reactivity (kOH) in the planetary boundary layer over southern Finland aboard the Zeppelin NT airship during the PEGASOS field campaign.

    Science.gov (United States)

    Broch, Sebastian; Gomm, Sebastian; Fuchs, Hendrik; Hofzumahaus, Andreas; Holland, Frank; Bachner, Mathias; Bohn, Birger; Häseler, Rolf; Jäger, Julia; Kaiser, Jennifer; Keutsch, Frank; Li, Xin; Lohse, Insa; Rohrer, Franz; Thayer, Mitchell; Tillmann, Ralf; Wegener, Robert; Mentel, Thomas F.; Kiendler-Scharr, Astrid; Wahner, Andreas

    2014-05-01

    The concentration of hydroxyl (OH) and hydroperoxy (HO2) radicals (also named HOx) and the total OH reactivity were measured over southern Finland and during transfer flights over Germany, Denmark and Sweden aboard the Zeppelin NT airship within the framework of the Pan-European Gas-AeroSOls-climate interaction Study (PEGASOS) field campaign in 2013. The measurements were performed with a remotely controlled Laser Induced Fluorescence (LIF) instrument which was installed on top of the airship. Together with a comprehensive set of trace gas (O3, CO, NO, NO2, HCHO, HONO, VOCs), photolysis frequencies and aerosol measurements as well as the measurement of meteorological parameters, these data provide the possibility to test the current understanding of the chemical processes in the planetary boundary layer (PBL) over different landscapes and in different chemical regimes. The unique flight performance of the Zeppelin NT allowed us to measure transects at a constant altitude as well as vertical profiles within the range of 80 m to 1000 m above ground. The transect flights show changes in the HOx distribution and kOH while crossing different chemical regimes on the way from Friedrichshafen, Germany to Jämijärvi, Finland over Germany, Denmark and Sweden. Vertical profile flights over the boreal forest close to Jämijärvi and Hyytiälä (both Finland) gave the opportunity to investigate the layering of the PBL and with that the vertical distribution of HOx and kOH with a high spatial and temporal resolution. Gradients in the HOx concentration and kOH were measured between the different layers during the early morning hours. The maximum radical concentrations found during the campaign were 1.0 x 107 cm-3 for OH and 1.0 x 109 cm-3 for HO2. The total OH reactivity measured in Finland was much lower than what was reported before in the literature from ground based measurements and ranged from 1 s-1 to 6 s-1. Acknowledgement: PEGASOS project funded by the European

  11. Enhancement of Biogas Production from Rice Husk by NaOH and Enzyme Pretreatment

    Directory of Open Access Journals (Sweden)

    Syafrudin

    2018-01-01

    Full Text Available Biogas is a renewable energy source that can be used as an alternative fuel to replace fossil fuel such as oil and natural gas. This research aims to analyze the impact of NaOH (Sodium hydroxide and enzyme usage on the production of rice husk biogas using Solid State Anaerobic Digestion (SS-AD. Generally, SS-AD occurs at solid concentrations higher than 15%. The waste of rice husk are used as substrate with a C/N ratio of 25% and the total of solid that are used is 21%. Rice husk contains high lignin, therefore it is handled with chemical and biological treatment. The chemical preliminary treatment was using NaOH with various concentrations from 3%, 6% and 9% while the biological preliminary treatment was using enzyme with various concentration from 5%, 8%, and 11%. The biogas that is produced then measured every two days during 60 days of research with the biogas volume as a parameter observed. The result of the research shows that preliminary treatment with NaOH and enzyme can increase the production of biogas. The highest biogas production was obtained by the NaOH pretreatment using 6% NaOH which was 497 ml and by enzyme pretreatment using 11% enzyme which was 667,5 ml.

  12. Enhancement of Biogas Production from Rice Husk by NaOH and Enzyme Pretreatment

    Science.gov (United States)

    Syafrudin; Nugraha, Winardi Dwi; Agnesia, Shandy Sarima; Matin, Hashfi Hawali Abdul; Budiyono

    2018-02-01

    Biogas is a renewable energy source that can be used as an alternative fuel to replace fossil fuel such as oil and natural gas. This research aims to analyze the impact of NaOH (Sodium hydroxide) and enzyme usage on the production of rice husk biogas using Solid State Anaerobic Digestion (SS-AD). Generally, SS-AD occurs at solid concentrations higher than 15%. The waste of rice husk are used as substrate with a C/N ratio of 25% and the total of solid that are used is 21%. Rice husk contains high lignin, therefore it is handled with chemical and biological treatment. The chemical preliminary treatment was using NaOH with various concentrations from 3%, 6% and 9% while the biological preliminary treatment was using enzyme with various concentration from 5%, 8%, and 11%. The biogas that is produced then measured every two days during 60 days of research with the biogas volume as a parameter observed. The result of the research shows that preliminary treatment with NaOH and enzyme can increase the production of biogas. The highest biogas production was obtained by the NaOH pretreatment using 6% NaOH which was 497 ml and by enzyme pretreatment using 11% enzyme which was 667,5 ml.

  13. Cluster self-organization of germanate systems: suprapolyhedral precursor clusters and self-assembly of K2Nd4Ge4O13(OH)4, K2YbGe4O10(OH), K2Sc2Ge2O7(OH)2, and KScGe2O6(PYR)

    International Nuclear Information System (INIS)

    Ilyushin, G.D.; Dem'yanets, L.N.

    2008-01-01

    One performed the computerized (the TOPOS 4.0 software package) geometric and topological analyses of all known types of K, TR-germanates (TR = La-Lu, Y, Sc, In). The skeleton structure are shown as three-dimensional 3D, K, TR, Ge-patterns (graphs) with remote oxygen atoms. TR 4 3 3 4 3 3 + T 4 3 4 3, K 2 YbGe 4 O 14 (OH) pattern, TR 6 6 3 6 + T1 6 8 6 + T2 3 6 8, K 2 Sc 2 Ge 2 O 7 (OH) 2 , TR 6 4 6 4 + T 6 4 6 and KScGe 2 O 6 - TR 6 6 3 6 3 4 + T1 6 3 6 + T2 6 4 3 patterns served as crystal-forming 2D TR,Ge-patterns for K 2 Nd 4 Ge 4 O 13 (OH) 4 . One performed the 3D-simulation of the mechanism of self-arrangement of the crystalline structures: cluster-precursor - parent chain - microlayer - microskeleton (super-precursor). Within K 2 Nd 4 Ge 4 O 13 (OH) 4 , K 2 Sc 2 Ge 2 O 7 (OH) 2 and KScGe 2 O 6 one identified the invariant type of the cyclic hexapolyhedral cluster-precursor consisting of TR-octahedrons linked by diorthogroups stabilized by K atoms. For K 2 Nd 4 Ge 4 O 13 (OH) 4 one determined the type of the cyclic tetrapolyhedral cluster-precursor consisting of TR-octavertices linked by tetrahedrons. The cluster CN within the layer just for KScGe 2 O 6 water-free germanate (the PYR pyroxene analog) is equal to 6 (the maximum possible value), while in the rest OH-containing germanates it constitutes 4. One studied the formation mechanism of Ge-radicals in the form of Ge 2 O 7 and Ge 4 O 13 groupings, GeO 3 chain and the tubular structure consisting of Ge 8 O 20 fixed cyclic groupings [ru

  14. Binding of ethanol on calcite: the role of the OH bond and its relevance to biomineralization

    DEFF Research Database (Denmark)

    Sand, K K; Yang, M; Makovicky, E

    2010-01-01

    The interaction of OH-containing compounds with calcite, CaCO(3), such as is required for the processes that control biomineralization, has been investigated in a low-water solution. We used ethanol (EtOH) as a simple, model, OH-containing organic compound, and observed the strength of its adsorp...

  15. Hydrothermal synthesis and structural analysis of new mixed oxyanion borates: Ba11B26O44(PO4)2(OH)6, Li9BaB15O27(CO3) and Ba3Si2B6O16

    Science.gov (United States)

    Heyward, Carla; McMillen, Colin D.; Kolis, Joseph

    2013-07-01

    Several new borate compounds, Ba11B26O44(PO4)2(OH)6 (1), Li9BaB15O27(CO3) (2), and Ba3Si2B6O16 (3) were synthesized containing other hetero-oxyanion building blocks in addition to the borate frameworks. They were all prepared under hydrothermal conditions and characterized by single crystal and powder X-ray diffraction, and IR spectroscopy. Crystal data: For 1; space group P21/c, a=6.8909 (14) Å, b=13.629 (3) Å, c=25.851 (5) Å, β=90.04 (3)°; For 2; space group P-31c, a=8.8599 (13) Å, c=15.148 (3) Å; For 3; space group P-1, a=5.0414 (10) Å, b=7.5602 (15) Å, c=8.5374 (17) Å, α=77.15 (3)°, β=77.84 (3)°, γ=87.41 (3)° for 3. Compounds 1 and 2 contain isolated oxyanions [PO4]3- and [CO3]2- respectively, sitting in channels created by the borate framework, while structure 3 has the [SiO4]4- groups directly bonded to the borate groups creating a B-O-Si framework.

  16. 25 (OH) D3 levels, incidence and recurrence of different clinical forms of BPPV.

    Science.gov (United States)

    Maslovara, Sinisa; Butkovic Soldo, Silva; Sestak, Anamarija; Milinkovic, Katarina; Rogic-Namacinski, Jasna; Soldo, Anamarija

    2017-06-11

    Benign Paroxysmal Positional Vertigo (BPPV) is the most common cause of dizziness in the general population. It is a condition with potential impact of reduced levels of vitamin D on its recurrent attacks. The aim of this study was to measure the serum levels of 25-hydroxyvitamin D3 (25-OH D3) in patients with BPPV and determine whether there is a difference in the serum levels of vitamin D3 between patients with and without recurrence, as well as between the different clinical forms of BPPV. The study included 40 patients who came to the regular medical examination, diagnosed with PC-BPPV based on the positive Dix-Hallpike's test. All patients underwent Epley manoeuvre after the diagnosis. Patients were classified according to current guidelines for levels of vitamin D3 in the serum in three groups: the deficiency, insufficiency and adequate level. The average serum level of 25-OH D3 among respondents was 20.78ng/mL, indicating a lack or insufficiency of the aforementioned 25-OH D3. According to the levels of 25-OH D3, most patients suffer from deficiency (47.5%). 7 (17.5%) respondents had adequate blood level of 25-OH D3, and 14 (35%) respondents suffer from insufficiency. A significant difference was not found in the serum level of 25-OH D3 between patients with and without BPPV recurrence. There was a significant difference in the serum levels of 25-OH D3 in comparison to the clinical form of the disease. Lower 25-OH D3 values were found in patients with canalithiasis compared to those with cupulolithiasis. There were no significant differences in the vitamin D3 serum level in patients with and without recurrence. The study showed a low level of serum vitamin D3 in most patients, indicating the need for supplemental therapy. Copyright © 2017 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  17. A high-temperature shock tube kinetic study for the branching ratios of isobutene+OH reaction

    KAUST Repository

    Khaled, Fathi; Giri, Binod; Farooq, Aamir

    2016-01-01

    Isobutene is an important intermediate formed during the oxidation of branched alkanes. It also appears as a byproduct during the combustion of methyl-tert-butyl-ether (MTBE) which is used as octane enhancer in gasolines. To understand better the oxidation kinetics of isobutene, we have measured the rate coefficients for the reaction of OH radicals with isobutene (HCC(CH)) behind reflected shock waves over the temperature range of 830-1289K and pressures near 1.5atm. The reaction progress was followed by measuring mole fraction of OH radicals near 306.7nm using UV laser absorption technique. Three deuterated isotopes, isobutene-1-d2 (DCC(CH)), isobutene-3-d6 (HCC(CD)) and isobutene-d8 (DCC(CD)) were employed to elucidate branching ratios of the allylic and vinylic H-abstraction from isobutene by OH radicals. H-abstraction from the allylic sites was found to be dominant and constituted about 75% of the total rate in the entire temperature range of the current work. The derived three-parameter Arrhenius expressions for site-specific H- and D- abstraction rates over 830-1289K are (units:cm mol s):k3,H=6.98×106(TK)1.77exp(-136.6KT) k3,D=4.42×106(TK)1.8exp(-361.7KT) k1,H=6.25×105(TK)2.16exp(-711.6KT) k1,D=3.13×107(TK)1.67exp(-1814KT) The subscript of . k identifies the position of H or D atom in isobutene according to the IUPAC nomenclature of alkenes.

  18. A high-temperature shock tube kinetic study for the branching ratios of isobutene+OH reaction

    KAUST Repository

    Khaled, Fathi

    2016-10-11

    Isobutene is an important intermediate formed during the oxidation of branched alkanes. It also appears as a byproduct during the combustion of methyl-tert-butyl-ether (MTBE) which is used as octane enhancer in gasolines. To understand better the oxidation kinetics of isobutene, we have measured the rate coefficients for the reaction of OH radicals with isobutene (HCC(CH)) behind reflected shock waves over the temperature range of 830-1289K and pressures near 1.5atm. The reaction progress was followed by measuring mole fraction of OH radicals near 306.7nm using UV laser absorption technique. Three deuterated isotopes, isobutene-1-d2 (DCC(CH)), isobutene-3-d6 (HCC(CD)) and isobutene-d8 (DCC(CD)) were employed to elucidate branching ratios of the allylic and vinylic H-abstraction from isobutene by OH radicals. H-abstraction from the allylic sites was found to be dominant and constituted about 75% of the total rate in the entire temperature range of the current work. The derived three-parameter Arrhenius expressions for site-specific H- and D- abstraction rates over 830-1289K are (units:cm mol s):k3,H=6.98×106(TK)1.77exp(-136.6KT) k3,D=4.42×106(TK)1.8exp(-361.7KT) k1,H=6.25×105(TK)2.16exp(-711.6KT) k1,D=3.13×107(TK)1.67exp(-1814KT) The subscript of . k identifies the position of H or D atom in isobutene according to the IUPAC nomenclature of alkenes.

  19. Toxicogenomic assessment of 6-OH-BDE47 induced developmental toxicity in chicken embryo

    Science.gov (United States)

    Hydroxylated and methoxylated polybrominated diphenyl ethers (OH-/MeO-PBDEs) are analogs of PBDEs with hundreds of possible structures and many of them can activate aryl hydrocarbon receptor (AhR), however, the in vivo evidence on the toxicity of OH-/MeO-PBDEs are still very limi...

  20. Small-Scale Dynamical Structures Using OH Airglow From Astronomical Observations

    Science.gov (United States)

    Franzen, C.; Espy, P. J.; Hibbins, R. E.; Djupvik, A. A.

    2017-12-01

    Remote sensing of perturbations in the hydroxyl (OH) Meinel airglow has often been used to observe gravity, tidal and planetary waves travelling through the 80-90 km region. While large scale (>1 km) gravity waves and the winds caused by their breaking are widely documented, information on the highest frequency waves and instabilities occurring during the breaking process is often limited by the temporal and spatial resolution of the available observations. In an effort to better quantify the full range of wave scales present near the mesopause, we present a series of observations of the OH Meinel (9,7) transition that were executed with the Nordic Optical Telescope on La Palma (18°W, 29°N). These measurements have a 24 s repetition rate and horizontal spatial resolutions at 87 km as small as 10 cm, allowing us to quantify the transition in the mesospheric wave domains as the gravity waves break. Temporal scales from hours to minutes, as well as sub-100 m coherent structures in the OH airglow have been observed and will be presented.

  1. The Effect of NaOH Concentration on pH, Egg White Protein Content and Yolk Colour Pidan Egg

    Directory of Open Access Journals (Sweden)

    Herly Evanuarini

    2017-11-01

    Full Text Available The purpose of this research was to determine the best treatment NaOH addition on pidan eggs. The materials used for this research was pidan made from duck egg, NaOH, salt, black tea and water. The method was used experiment laboratory and Completely Randomized Design (CRD using 4 treatments and 4 replications. The treatments were T0 (control, T1 (1.4%, T2 (2.8% and T3 (4.2%. The data were analyzed by Analysis of Variance (ANOVA if there was significantly continued by Duncan’s Multiple Range Test (DMRT. The result showed that NaOH concentration on pidan eggs gave significant effect (P<0.05 on albumen protein content, gave highly significant (P<0.01 on pH value and yolk colour. The conclusion of this research was 4.2% NaOH addition on pidan egg was the best treatment with gave result yolk and albumen pH: 10.69; 10.25, albumen protein content 26.89%, egg yolk colour L* (lightness, a* (redness, b* (yellowness:  26.89; 11.33, and 26.77. The suggestion of this research was ussed different immersion time on pidan egg production.

  2. The Use of Mg(OH2 in the Final Peroxide Bleaching Stage of Wheat Straw Pulp

    Directory of Open Access Journals (Sweden)

    Yan-Lan Liu

    2013-11-01

    Full Text Available Magnesium-based alkali is an attractive alkaline source for the peroxide bleaching of high-yield pulp. However, little information is available on Mg(OH2 application in the final peroxide bleaching stage of wheat straw pulp. The use of Mg(OH2 was demonstrated as a partial replacement for NaOH in the peroxide bleaching of a chelated oxygen-delignified wheat straw pulp. The yield, viscosity, and strength properties of bleached pulp significantly increased with increasing replacement ratio of Mg(OH2, while the chemical oxygen demand load (COD of filtrate was decreased. For similar brightness of bleached pulp at a 24% replacement ratio of Mg(OH2, the tensile and tear indices were higher, by 2.1 Nm.g-1 and 1.75 mN*m2.g-1, respectively, than that of control pulp bleached with NaOH as the sole alkaline source. When the MgSO4 was eliminated and the dosage of Na2SiO3 was decreased in the bleaching process, the tear and burst indices of the bleached pulp were also enhanced, with the brightness maintained. Scanning electron microscopy (SEM showed that more swelling occurred in the fibers of bleached pulp from the Mg(OH2-based bleaching process. Fiber analysis indicated that peroxide bleaching with Mg(OH2 increased the proportion of fiber lengths between 0.20 to 1.20 mm and 1.20 to 7.60 mm.

  3. Comparison of OH Reactivity Instruments in the Atmosphere Simulation Chamber SAPHIR.

    Science.gov (United States)

    Fuchs, H.; Novelli, A.; Rolletter, M.; Hofzumahaus, A.; Pfannerstill, E.; Edtbauer, A.; Kessel, S.; Williams, J.; Michoud, V.; Dusanter, S.; Locoge, N.; Zannoni, N.; Gros, V.; Truong, F.; Sarda Esteve, R.; Cryer, D. R.; Brumby, C.; Whalley, L.; Stone, D. J.; Seakins, P. W.; Heard, D. E.; Schoemaecker, C.; Blocquet, M.; Fittschen, C. M.; Thames, A. B.; Coudert, S.; Brune, W. H.; Batut, S.; Tatum Ernest, C.; Harder, H.; Elste, T.; Bohn, B.; Hohaus, T.; Holland, F.; Muller, J. B. A.; Li, X.; Rohrer, F.; Kubistin, D.; Kiendler-Scharr, A.; Tillmann, R.; Andres, S.; Wegener, R.; Yu, Z.; Zou, Q.; Wahner, A.

    2017-12-01

    Two campaigns were conducted performing experiments in the atmospheric simulation chamber SAPHIR at Forschungszentrum Jülich in October 2015 and April 2016 to compare hydroxyl (OH) radical reactivity (kOH) measurements. Chemical conditions were chosen either to be representative of the atmosphere or to test potential limitations of instruments. The results of these campaigns demonstrate that OH reactivity can be accurately measured for a wide range of atmospherically relevant chemical conditions (e.g. water vapor, nitrogen oxides, various organic compounds) by all instruments. The precision of the measurements is higher for instruments directly detecting hydroxyl radicals (OH), whereas the indirect Comparative Reactivity Method (CRM) has a higher limit of detection of 2s-1 at a time resolution of 10 to 15 min. The performances of the instruments were systematically tested by stepwise increasing, for example, the concentrations of carbon monoxide (CO), water vapor or nitric oxide (NO). In further experiments, mixtures of organic reactants were injected in the chamber to simulate urban and forested environments. Overall, the results show that instruments are capable of measuring OH reactivity in the presence of CO, alkanes, alkenes and aromatic compounds. The transmission efficiency in Teflon inlet lines could have introduced systematic errors in measurements for low-volatile organic compounds in some instruments. CRM instruments exhibited a larger scatter in the data compared to the other instruments. The largest differences to the reference were observed by CRM instruments in the presence of terpenes and oxygenated organic compounds. In some of these experiments, only a small fraction of the reactivity is detected. The accuracy of CRM measurements is most likely limited by the corrections that need to be applied in order to account for known effects of, for example, deviations from pseudo-first order conditions, nitrogen oxides or water vapor on the measurement

  4. Synthesis and adsorption performance of Mg(OH)2 hexagonal nanosheet–graphene oxide composites

    International Nuclear Information System (INIS)

    Liu, Mengdi; Xu, Jing; Cheng, Bei; Ho, Wingkei; Yu, Jiaguo

    2015-01-01

    Graphical abstract: - Highlights: • Mg(OH) 2 hexagonal nanosheets with various mass of GO were prepared. • Mg(OH) 2 –GO composite showed enhanced adsorption capacity to congo red. • Zeta potential was used to explain preparation and adsorption mechanism. - Abstract: A series of Mg(OH) 2 hexagonal nanosheet–graphene oxide (GO) composites were synthesized through a simple hydrothermal method using magnesium nitrate and GO as precursors, sodium nitrate and sodium oxalate as additives, and sodium hydroxide and ammonia as precipitants. The as-prepared samples were characterized by X-ray diffraction, nitrogen adsorption–desorption isotherms, Raman spectroscopy, zeta potential analysis, and scanning electron microscopy (SEM). The adsorption affinity of the as-prepared samples toward congo red (CR) in water was analyzed and investigated. Results indicated that GO addition influenced the thickness, morphology, and adsorption performance of Mg(OH) 2 hexagonal nanosheets. As GO concentration increased, the thickness decreased. Especially at high GO concentration (1 wt%), Mg(OH) 2 hexagonal nanosheets changed into aggregated flower-like spheres. Addition of small amounts of GO also increased the adsorption capacity of Mg(OH) 2 . The equilibrium adsorption data of CR on the composite were further investigated by Langmuir and Freundlich models, indicating that the Langmuir model was much more suitable for the experimental data. The sample prepared with 0.5 wt% GO showed the highest adsorption capacity with 118 mg g −1 . The experimental data were then fitted using pseudo-second order kinetics, suggesting that pseudo-second order kinetics could well describe the adsorption of CR on composites. Adsorption thermodynamics analysis showed that the adsorption activation energy was 29.2 kJ mol −1 , suggesting that the adsorption of CR onto the samples was physical adsorption. Adsorption between the samples and CR was mainly due to the strong electrostatic attraction

  5. Variations in VLT/UVES-based OH rotational temperatures for time scales from hours to 15 years

    Science.gov (United States)

    Noll, Stefan; Kimeswenger, Stefan; Proxauf, Bastian; Kausch, Wolfgang; Unterguggenberger, Stefanie; Jones, Amy M.

    2017-04-01

    Hydroxyl (OH) emission is an important tracer of the climate, chemistry, and dynamics of the Earth's mesopause region. However, the relation of intensity variations in different OH lines is not well understood yet. This is critical for the most popular use of OH lines: the estimate of ambient temperatures based on transitions at low rotational levels of the same band. It is possible that the measured variability of the derived rotational temperature does not coincide with changes in the ambient temperature. Such differences can be caused by varying deviations from the local thermodynamic equilibrium (LTE) for the population distribution over the considered rotational levels. The non-LTE effects depend on the ratio of the thermalising collisions (mostly related to molecular oxygen) and competing radiative transitions or collisions without thermalisation of the rotational level distribution. Therefore, significant changes in the vertical structure of excited OH and its main quenchers can affect the temperature measurements. We have investigated the variability of OH rotational temperatures and the corresponding contributions of non-LTE effects for different OH bands and time scales up to 15 years based on data of the high-resolution echelle spectrograph UVES at the Very Large Telescope at Cerro Paranal in Chile. In order to link the measured rotational temperatures with the structure of the OH emission layer, we have also studied OH emission and kinetic temperature profiles from the multi-channel radiometer SABER on the TIMED satellite taken between 2002 and 2015. The results show that non-LTE contributions can significantly affect the OH rotational temperatures. Their variations can be especially strong during the night and for high upper vibrational levels of the transitions, where amplitudes of several Kelvins can be measured. They appear to be weak if long-term variations such as those caused by the solar cycle are investigated. These differences in the response

  6. Inversion mechanisms for OH main lines astrophysical masers

    International Nuclear Information System (INIS)

    Elitzur, M.

    1977-01-01

    Excitation processes that can lead to inversion of the main lines of the OH ground state are discussed. Due to the frequency dependence of the emission coefficient of dust, far-IR emitted by warm enough dust can excite the upper halves of the Λ-doublets of rotational levels more strongly than the lower halves. The cascade back to the ground state will then invert the main lines and it is shown that this mechanism can explain rather well the main lines emission from OH-IR stars. The main lines masers associated with compact HII regions are discussed extensively. It is argued that the most plausible explanation for them is a model based on the mechanism suggested some time ago by Johnston where the inversion is due to collisional excitation by streams of uni-directional electrons. (author)

  7. Produccion Gaseosa del Cometa Halley: Erupciones Y Fotodisociacion del Radical OH

    Science.gov (United States)

    Silva, A. M.; Mirabel, I. F.

    1990-11-01

    RESUMEN:En este trabajo informamos la detecci6n de 20 erupciones en la li'nea de =18cm (1667MHz) del radical OH en el Cometa Halley.Las observaciones incluyen todos los monitoreos existentes y se extienden desde 120 dias antes del perihelio hasta 90 dias despues.Se detectan bruscos crecimientos en el flujo medido,hasta un factor 1O,seguidos por decaimientos lentos asociados con la fotodisociaci6n del OH. Se obtuvieron valores para el tiempo de vida fotoquimico del OH y del H2O basandose en el modelo desarrollado previamente por Silva(1988). Esos tiempos de vida estan de acuerdo con predicciones teoricas y con las observaciones en el Ultravioleta, y los resultados, los que son fuertemente dependientes de la velocidad heliocentrica del Coineta (variando hasta un factor 6), han sido calculados para varios rangos de velocidad entre +28 y -28 km/seg. Key wo'L :

  8. Why a German "Oh" Is Not Necessarily an English "Oh": Showing Understanding and Emotions with Change-of-State Tokens

    Science.gov (United States)

    Linneweber, Judith

    2016-01-01

    This paper presents a two-session teaching unit on German change-of-state tokens such as "oh," "ach" and "achso." Goal is to teach students the appropriate reaction through change-of-state tokens in various situations. Students are provided with authentic data based on empirical research in conversation analysis (CA).…

  9. Serum 25(OH)D seasonality in urologic patients from central Italy.

    Science.gov (United States)

    Calgani, Alessia; Iarlori, Marco; Rizi, Vincenzo; Pace, Gianna; Bologna, Mauro; Vicentini, Carlo; Angelucci, Adriano

    2016-09-01

    insufficient solar exposure in summer. The relatively high outdoor time that emerged to be correlated with sufficient serum 25(OH)D in autumn warrants further studies to individuate potential risk co-variables for hypovitaminosis D in elderly men. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Gas-phase synthesis and structure of monomeric ZnOH: a model species for metalloenzymes and catalytic surfaces.

    Science.gov (United States)

    Zack, Lindsay N; Sun, Ming; Bucchino, Matthew P; Clouthier, Dennis J; Ziurys, Lucy M

    2012-02-16

    Monomeric ZnOH has been studied for the first time using millimeter and microwave gas-phase spectroscopy. ZnOH is important in surface processes and at the active site of the enzyme carbonic anhydrase. In the millimeter-wave direct-absorption experiments, ZnOH was synthesized by reacting zinc vapor, produced in a Broida-type oven, with water. In the Fourier-transform microwave measurements, ZnOH was produced in a supersonic jet expansion of CH(3)OH and zinc vapor, created by laser ablation. Multiple rotational transitions of six ZnOH isotopologues in their X(2)A' ground states were measured over the frequency range of 22-482 GHz, and splittings due to fine and hyperfine structure were resolved. An asymmetric top pattern was observed in the spectra, showing that ZnOH is bent, indicative of covalent bonding. From these data, spectroscopic constants and an accurate structure were determined. The Zn-O bond length was found to be similar to that in carbonic anhydrase and other model enzyme systems.

  11. New insights for mesospheric OH: multi-quantum vibrational relaxation as a driver for non-local thermodynamic equilibrium

    Directory of Open Access Journals (Sweden)

    K. S. Kalogerakis

    2018-01-01

    Full Text Available The question of whether mesospheric OH(v rotational population distributions are in equilibrium with the local kinetic temperature has been debated over several decades. Despite several indications for the existence of non-equilibrium effects, the general consensus has been that emissions originating from low rotational levels are thermalized. Sky spectra simultaneously observing several vibrational levels demonstrated reproducible trends in the extracted OH(v rotational temperatures as a function of vibrational excitation. Laboratory experiments provided information on rotational energy transfer and direct evidence for fast multi-quantum OH(high-v vibrational relaxation by O atoms. We examine the relationship of the new relaxation pathways with the behavior exhibited by OH(v rotational population distributions. Rapid OH(high-v + O multi-quantum vibrational relaxation connects high and low vibrational levels and enhances the hot tail of the OH(low-v rotational distributions. The effective rotational temperatures of mesospheric OH(v are found to deviate from local thermodynamic equilibrium for all observed vibrational levels. Dedicated to Tom G. Slanger in celebration of his 5 decades of research in aeronomy.

  12. Detection of 12 micron Mg I and OH lines in stellar spectra

    Science.gov (United States)

    Jennings, D. E.; Deming, D.; Wiedemann, G. R.; Keady, J. J.

    1986-01-01

    Infrared lines of Mg I and OH have been detected in stellar spectra near 12.3 microns. The Mg I 7i-6h transition was seen in Alpha Ori and Alpha Tau, and the R2e(23.5) and R1f(24.5) transitions of OH were seen in Alpha Ori. All lines appear in absorption, in contrast to the solar spectrum where the Mg I line shows a prominent emission core. The lack of emission in these low surface gravity stars is due to a greatly reduced volume recombination rate for the high-n states of Mg I, which is not fully compensated by the increased chromospheric scale height. The OH equivalent widths are sensitive to the temperature structure of the upper photosphere of Alpha Ori, and they indicate that the photosphere near tau 5000 of about 10 to the -5th is approximately 100 K hotter than is given by flux constant models. The OH measurements agree more closely with the 1981 semiemprical model of Basri, Linsky, and Eriksson (1981), which is based on Ca II and Mg II ultraviolet features.

  13. [Effect of Ca(OH)2 on the cytotoxicity of lipopolysaccharide extracted from Porphyromonas endodontalis in vitro].

    Science.gov (United States)

    Guo, Jia-jie; Qiu, Li-hong; Yu, Ya-qiong; Xu, Li-ya; Fan, Yun-qian; Zhong, Ming

    2014-02-01

    To detect the degradation of Ca(OH)2 on lipopolysaccharide (LPS) extracted from Porphyromonas endodontalis (P.e) in vitro and estimate the influence of P.e LPS pretreated with Ca(OH)2 on the proliferation of MC3T3-E1 cells. The effect of Ca(OH)2 on MC3T3-E1 cell proliferation was detected by methyl thiazolyl tetrazolium (MTT) assay. Then P.e LPS was treated with Ca(OH)2 for 30 mins or 60 mins at 37 degrees centigrade in vitro and the activity of P.e LPS was evaluated by Chromogenic End-point Tachypleus Amebocyte Lysate (CE TAL) test. Finally, MC3T3-E1 cells were exposed to P.e LPS pretreated with 15% Ca(OH)2 for 1, 3 and 5 d, and the cell proliferation was measured using the MTT assay comparing with the P.e LPS control group. SPSS 13.0 software package was used for statistical analysis. Compared with the negative control, exposing cells to 5%, 10% and 15% Ca(OH)2 had greatly promoted MC3T3-E1 cell proliferation. P.e LPS treated with 10% and 15% Ca(OH)2 both presented the best results by CE TAL and significant difference compared with P.e LPS control group. When 10 μg/mL P.e LPS was pretreated with 15% Ca(OH)2, no inhibition of MC3T3-E1 cell proliferation was noted. Ca(OH)2 detoxifies P.e LPS in vitro, mitigates the impact of P.e LPS on MC3T3-E1 cell proliferation. Supported by Science and Technology Projects of Liaoning Province (2011225020).

  14. Redetermination of the cubic struvite analogue Cs[Mg(OH26](AsO4

    Directory of Open Access Journals (Sweden)

    Matthias Weil

    2009-01-01

    Full Text Available In contrast to the previous refinement from photographic data [Ferrari et al. (1955. Gazz. Chim. Ital. 84, 169–174], the present redetermination of the title compound, caesium hexaaquamagnesium arsenate(V, revealed the Cs atom to be on Wyckoff position 4d instead of Wyckoff position 4b of space group Foverline{4}3m. The structure can be derived from the halite structure. The centres of the complex [Mg(OH26] octahedra and the AsO4 tetrahedra (both with overline{4}3m symmetry are on the respective Na and Cl positions. The building units are connected to each other by O—H...O hydrogen bonds. The Cs+ cations (overline{4}3m symmetry are located in the voids of this arrangement and exhibit a regular cuboctahedral 12-coordination to the O atoms of the water molecules. The O atom bonded to As has 2mm site symmetry (Wyckoff position 24f and the water-molecule O atom has m site symmetry (Wyckoff position 48h.

  15. 76 FR 66250 - Television Broadcasting Services; Cleveland, OH

    Science.gov (United States)

    2011-10-26

    ...] Television Broadcasting Services; Cleveland, OH AGENCY: Federal Communications Commission. ACTION: Proposed rule. SUMMARY: The Commission has before it a petition for rulemaking filed by Community Television of Ohio License, LLC (``Community Television''), the licensee of station WJW (TV), channel 8, Cleveland...

  16. Biomolecule-assisted synthesis of In(OH)₃ nanocubes and In₂O₃ nanoparticles: photocatalytic degradation of organic contaminants and CO oxidation.

    Science.gov (United States)

    Nayak, Arpan Kumar; Lee, Seungwon; Sohn, Youngku; Pradhan, Debabrata

    2015-12-04

    The synthesis of nanostructured materials without any hazardous organic chemicals and expensive capping reagents is one of the challenges in nanotechnology. Here we report on the L-arginine (a biomolecule)-assisted synthesis of single crystalline cubic In(OH)3 nanocubes of a size in the range of 30-60 nm along the diagonal using hydrothermal methods. Upon calcining at 750 °C for 1 h in air, In(OH)3 nanocubes are transformed into In2O3 nanoparticles (NPs) with voids. The morphology transformation and formation of voids with the increase of the calcination temperature is studied in detail. The possible mechanism of the voids' formation is discussed on the basis of the Kirkendall effect. The photocatalytic properties of In(OH)3 nanocubes and In2O3 NPs are studied for the degradation of rhodamin B and alizarin red S. Furthermore, the CO oxidation activity of In(OH)3 nanocubes and In2O3 NPs is examined. The photocatalytic and CO oxidation activity are measured to be higher for In2O3 NPs than for In(OH)3 nanocubes. This is attributed to the lower energy gap and higher specific surface area of the former. The present green synthesis has potential for the synthesis of other inorganic nanomaterials.

  17. Carbon-14 immobilization via the CO2-Ba(OH)2 hydrate gas-solid reaction

    International Nuclear Information System (INIS)

    Haag, G.L.

    1980-01-01

    Although no restrictions have been placed on the release of carbon-14, it has been identified as a potential health hazard due to the ease in which it may be assimilated into the biosphere. The intent of the Carbon-14 Immobilization Program, funded through the Airborne Waste Program Management Office, is to develop and demonstrate a novel process for restricting off-gas releases of carbon-14 from various nuclear facilities. The process utilizes the CO 2 -Ba(OH) 2 hydrate gas-solid reaction to directly remove and immobilize carbon-14. The reaction product, BaCO 3 , possesses both the thermal and chemical stability desired for long-term waste disposal. The process is capable of providing decontamination factors in excess of 1000 and reactant utilization of greater than 99% in the treatment of high volumetric, airlike (330 ppM CO 2 ) gas streams. For the treatment of an air-based off-gas stream, the use of packed beds of Ba(OH) 2 .8H 2 O flakes to remove CO 2 has been demonstrated. However, the operating conditions must be maintained between certain upper and lower limits with respect to the partial pressure of water. If the water vapor pressure in the gas is less than the dissociation vapor pressure of Ba(OH) 2 .8H 2 O, the bed will deactivate. If the vapor pressure is considerably greater, pressure drop problems will increase with increasing humidity as the particles curl and degrade. Results have indicated that when operated in the proper regime, the bulk of the increase in pressure drop results from the conversion of Ba(OH) 2 .8H 2 O to BaCO 3 and not from the hydration of the commercial Ba(OH) 2 .8H 2 O (i.e. Ba(OH) 2 .7.50H 2 O) to Ba(OH) 2 .8H 2 O

  18. 76 FR 32069 - Safety Zone; Lorain Independence Day Fireworks, Black River, Lorain, OH

    Science.gov (United States)

    2011-06-03

    ...-AA00 Safety Zone; Lorain Independence Day Fireworks, Black River, Lorain, OH AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is establishing a temporary safety zone at the mouth of the Black River, Lorain, OH for the Lorain Independence Day Fireworks. This zone is intended to...

  19. Volatility and lifetime against OH heterogeneous reaction of ambient isoprene-epoxydiols-derived secondary organic aerosol (IEPOX-SOA

    Directory of Open Access Journals (Sweden)

    W. Hu

    2016-09-01

    Full Text Available Isoprene-epoxydiols-derived secondary organic aerosol (IEPOX-SOA can contribute substantially to organic aerosol (OA concentrations in forested areas under low NO conditions, hence significantly influencing the regional and global OA budgets, accounting, for example, for 16–36 % of the submicron OA in the southeastern United States (SE US summer. Particle evaporation measurements from a thermodenuder show that the volatility of ambient IEPOX-SOA is lower than that of bulk OA and also much lower than that of known monomer IEPOX-SOA tracer species, indicating that IEPOX-SOA likely exists mostly as oligomers in the aerosol phase. The OH aging process of ambient IEPOX-SOA was investigated with an oxidation flow reactor (OFR. New IEPOX-SOA formation in the reactor was negligible, as the OFR does not accelerate processes such as aerosol uptake and reactions that do not scale with OH. Simulation results indicate that adding  ∼  100 µg m−3 of pure H2SO4 to the ambient air allows IEPOX-SOA to be efficiently formed in the reactor. The heterogeneous reaction rate coefficient of ambient IEPOX-SOA with OH radical (kOH was estimated as 4.0 ± 2.0  ×  10−13 cm3 molec−1 s−1, which is equivalent to more than a 2-week lifetime. A similar kOH was found for measurements of OH oxidation of ambient Amazon forest air in an OFR. At higher OH exposures in the reactor (>  1  ×  1012 molec cm−3 s, the mass loss of IEPOX-SOA due to heterogeneous reaction was mainly due to revolatilization of fragmented reaction products. We report, for the first time, OH reactive uptake coefficients (γOH =  0.59 ± 0.33 in SE US and γOH =  0.68 ± 0.38 in Amazon for SOA under ambient conditions. A relative humidity dependence of kOH and γOH was observed, consistent with surface-area-limited OH uptake. No decrease of kOH was observed as OH concentrations increased. These observations of physicochemical

  20. Identification of new solar OH lines in the 10--12 micron region

    International Nuclear Information System (INIS)

    Goldman, A.; Murcray, F.J.; Gillis, J.R.; Murcray, D.G.

    1981-01-01

    High-resolution (0.02 cm -1 ) infrared solar spectra obtained with a balloon-borne interferometer reveal new solar absorption features, which appear as regularly spaced quartets, in the 825--960 cm -1 region. The lines are interpreted as high N'' (25--33) pure rotation lines of solar OH. An effective amount of approx.8 x 10 15 molecules cm -2 of OH is estimated from the spectra

  1. Investigation of OH Radical Regeneration from Isoprene Oxidation Across Different NOx Regimes in the Atmosphere Simulation Chamber SAPHIR

    Science.gov (United States)

    Novelli, A.; Bohn, B.; Dorn, H. P.; Häseler, R.; Hofzumahaus, A.; Kaminski, M.; Yu, Z.; Li, X.; Tillmann, R.; Wegener, R.; Fuchs, H.; Kiendler-Scharr, A.; Wahner, A.

    2017-12-01

    The hydroxyl radical (OH) is the dominant daytime oxidant in the troposphere. It starts the degradation of volatile organic compounds (VOC) originating from both anthropogenic and biogenic emissions. Hence, it is a crucial trace species in model simulations as it has a large impact on many reactive trace gases. Many field campaigns performed in isoprene dominated environment in low NOx conditions have shown large discrepancies between the measured and the modelled OH radical concentrations. These results have contributed to the discovery of new regeneration paths for OH radicals from isoprene-OH second generation products with maximum efficiency at low NO. The current chemical models (e.g. MCM 3.3.1) include this novel chemistry allowing for an investigation of the validity of the OH regeneration at different chemical conditions. Over 11 experiments focusing on the OH oxidation of isoprene were performed at the SAPHIR chamber in the Forschungszentrum Jülich. Measurements of VOCs, NOx, O3, HONO were performed together with the measurement of OH radicals (by both LIF-FAGE and DOAS) and OH reactivity. Within the simulation chamber, the NO mixing ratio was varied between 0.05 to 2 ppbv allowing the investigation of both the "new" regeneration path for OH radicals and the well-known NO+HO2 mechanism. A comparison with the MCM 3.3.1 that includes the upgraded LIM1 mechanism showed very good agreement (within 10%) for the OH data at all concentrations of NOx investigated. Comparison with different models, without LIM1 and with updated rates for the OH regeneration, will be presented together with a detailed analysis of the impact of this study on results from previous field campaigns.

  2. ON THE ORIGIN OF C_4H AND CH_3OH IN PROTOSTELLAR ENVELOPES

    International Nuclear Information System (INIS)

    Lindberg, Johan E.; Charnley, Steven B.; Cordiner, Martin A.

    2016-01-01

    The formation pathways of different types of organic molecules in protostellar envelopes and other regions of star formation are subjects of intense current interest. We present here observations of C_4H and CH_3OH, tracing two distinct groups of interstellar organic molecules, toward 16 protostars in the Ophiuchus and Corona Australis molecular clouds. Together with observations in the literature, we present C_4H and CH_3OH data from single-dish observations of 40 embedded protostars. We find no correlation between the C_4H and CH_3OH column densities in this large sample. Based on this lack of correlation, a difference in line profiles between C_4H and CH_3OH, and previous interferometric observations of similar sources, we propose that the emission from these two molecules is spatially separated, with the CH_3OH tracing gas that has been transiently heated to high (∼70–100 K) temperatures and the C_4H tracing the cooler large-scale envelope where CH_4 molecules have been liberated from ices. These results provide insight in the differentiation between hot corino and warm carbon-chain chemistry in embedded protostars.

  3. Thermochemical Storage of Middle Temperature Wasted Heat by Functionalized C/Mg(OH2 Hybrid Materials

    Directory of Open Access Journals (Sweden)

    Emanuela Mastronardo

    2017-01-01

    Full Text Available For the thermochemical performance implementation of Mg(OH2 as a heat storage medium, several hybrid materials have been investigated. For this study, high-performance hybrid materials have been developed by exploiting the authors’ previous findings. Expanded graphite (EG/carbon nanotubes (CNTs-Mg(OH2 hybrid materials have been prepared through Mg(OH2 deposition-precipitation over functionalized, i.e., oxidized, or un-functionalized EG or CNTs. The heat storage performances of the carbon-based hybrid materials have been investigated through a laboratory-scale experimental simulation of the heat storage/release cycles, carried out by a thermogravimetric apparatus. This study offers a critical evaluation of the thermochemical performances of developed materials through their comparison in terms of heat storage and output capacities per mass and volume unit. It was demonstrated that both EG and CNTs improves the thermochemical performances of the storage medium in terms of reaction rate and conversion with respect to pure Mg(OH2. With functionalized EG/CNTs-Mg(OH2, (i the potential heat storage and output capacities per mass unit of Mg(OH2 have been completely exploited; and (ii higher heat storage and output capacities per volume unit were obtained. That means, for technological applications, as smaller volume at equal stored/released heat.

  4. GNOSIS: THE FIRST INSTRUMENT TO USE FIBER BRAGG GRATINGS FOR OH SUPPRESSION

    Energy Technology Data Exchange (ETDEWEB)

    Trinh, Christopher Q.; Ellis, Simon C.; Bland-Hawthorn, Joss; Bryant, Julia; O' Byrne, John [Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006 (Australia); Lawrence, Jon S.; Horton, Anthony J.; Shortridge, Keith; Case, Scott; Colless, Matthew; Gers, Luke; Lee, Steve; Miziarski, Stan [Australian Astronomical Observatory, 105 Delhi Road, North Ryde, P.O. Box 915, NSW 1670 (Australia); Leon-Saval, Sergio G. [Institute of Photonics and Optical Science, School of Physics, University of Sydney, NSW 2006 (Australia); Couch, Warrick; Glazebrook, Karl [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218, Hawthorn, VIC 3122 (Australia); Freeman, Kenneth [Research School of Astronomy and Astrophysics, Australian National University, Weston Creek, ACT 2611 (Australia); Loehmannsroeben, Hans-Gerd [innoFSPEC-Institut fuer Chemie/Physikalische Chemie, Universitaet Potsdam, Karl-Liebknecht-Strasse 24-25, D-14476 Potsdam-Golm (Germany); Haynes, Roger; Roth, Martin M., E-mail: c.trinh@physics.usyd.edu.au [innoFSPEC-Leibniz-Institut fuer Astrophysik Potsdam, An der Sternwarte 16, D-14482 Potsdam (Germany); and others

    2013-02-01

    The near-infrared is an important part of the spectrum in astronomy, especially in cosmology because the light from objects in the early universe is redshifted to these wavelengths. However, deep near-infrared observations are extremely difficult to make from ground-based telescopes due to the bright background from the atmosphere. Nearly all of this background comes from the bright and narrow emission lines of atmospheric hydroxyl (OH) molecules. The atmospheric background cannot be easily removed from data because the brightness fluctuates unpredictably on short timescales. The sensitivity of ground-based optical astronomy far exceeds that of near-infrared astronomy because of this long-standing problem. GNOSIS is a prototype astrophotonic instrument that utilizes 'OH suppression fibers' consisting of fiber Bragg gratings and photonic lanterns to suppress the 103 brightest atmospheric emission doublets between 1.47 and 1.7 {mu}m. GNOSIS was commissioned at the 3.9 m Anglo-Australian Telescope with the IRIS2 spectrograph to demonstrate the potential of OH suppression fibers, but may be potentially used with any telescope and spectrograph combination. Unlike previous atmospheric suppression techniques GNOSIS suppresses the lines before dispersion and in a manner that depends purely on wavelength. We present the instrument design and report the results of laboratory and on-sky tests from commissioning. While these tests demonstrated high throughput ( Almost-Equal-To 60%) and excellent suppression of the skylines by the OH suppression fibers, surprisingly GNOSIS produced no significant reduction in the interline background and the sensitivity of GNOSIS+IRIS2 is about the same as IRIS2. It is unclear whether the lack of reduction in the interline background is due to physical sources or systematic errors as the observations are detector noise dominated. OH suppression fibers could potentially impact ground-based astronomy at the level of adaptive optics or

  5. OH and HO2 chemistry in clean marine air during SOAPEX-2

    Directory of Open Access Journals (Sweden)

    R. Sommariva

    2004-01-01

    Full Text Available Model-measurement comparisons of HOx in extremely clean air ([NO] The free-radical chemistry was studied using a zero-dimensional box-model based upon the Master Chemical Mechanism (MCM. Two versions of the model were used, with different levels of chemical complexity, to explore the role of hydrocarbons upon free-radical budgets under very clean conditions. The "detailed" model was constrained to measurements of CO, CH4 and 17 NMHCs, while the "simple" model contained only the CO and CH4 oxidation mechanisms, together with inorganic chemistry. The OH and HO2 (HOx concentrations predicted by the two models agreed to within 5–10%. The model results were compared with the HOx concentrations measured by the FAGE (Fluorescence Assay by Gas Expansion technique during four days of clean Southern Ocean marine boundary layer (MBL air. The models overestimated OH concentrations by about 10% on two days and about 20% on the other two days. HO2 concentrations were measured during two of these days and the models overestimated the measured concentrations by about 40%. Better agreement with measured HO2 was observed by using data from several MBL aerosol measurements to estimate the aerosol surface area and by increasing the HO2 uptake coefficient to unity. This reduced the modelled HO2 overestimate by ~40%, with little effect on OH, because of the poor HO2 to OH conversion at the low ambient NOx concentrations. Local sensitivity analysis and Morris One-At-A-Time analysis were performed on the "simple" model, and showed the importance of reliable measurements of j(O1D and [HCHO] and of the kinetic parameters that determine the efficiency of O(1D to OH and HCHO to HO2 conversion. A 2σ standard deviation of 30–40% for OH and 25–30% for HO2 was estimated for the model calculations using a Monte Carlo technique coupled with Latin Hypercube Sampling (LHS.

  6. GNOSIS: THE FIRST INSTRUMENT TO USE FIBER BRAGG GRATINGS FOR OH SUPPRESSION

    International Nuclear Information System (INIS)

    Trinh, Christopher Q.; Ellis, Simon C.; Bland-Hawthorn, Joss; Bryant, Julia; O'Byrne, John; Lawrence, Jon S.; Horton, Anthony J.; Shortridge, Keith; Case, Scott; Colless, Matthew; Gers, Luke; Lee, Steve; Miziarski, Stan; Leon-Saval, Sergio G.; Couch, Warrick; Glazebrook, Karl; Freeman, Kenneth; Löhmannsröben, Hans-Gerd; Haynes, Roger; Roth, Martin M.

    2013-01-01

    The near-infrared is an important part of the spectrum in astronomy, especially in cosmology because the light from objects in the early universe is redshifted to these wavelengths. However, deep near-infrared observations are extremely difficult to make from ground-based telescopes due to the bright background from the atmosphere. Nearly all of this background comes from the bright and narrow emission lines of atmospheric hydroxyl (OH) molecules. The atmospheric background cannot be easily removed from data because the brightness fluctuates unpredictably on short timescales. The sensitivity of ground-based optical astronomy far exceeds that of near-infrared astronomy because of this long-standing problem. GNOSIS is a prototype astrophotonic instrument that utilizes 'OH suppression fibers' consisting of fiber Bragg gratings and photonic lanterns to suppress the 103 brightest atmospheric emission doublets between 1.47 and 1.7 μm. GNOSIS was commissioned at the 3.9 m Anglo-Australian Telescope with the IRIS2 spectrograph to demonstrate the potential of OH suppression fibers, but may be potentially used with any telescope and spectrograph combination. Unlike previous atmospheric suppression techniques GNOSIS suppresses the lines before dispersion and in a manner that depends purely on wavelength. We present the instrument design and report the results of laboratory and on-sky tests from commissioning. While these tests demonstrated high throughput (≈60%) and excellent suppression of the skylines by the OH suppression fibers, surprisingly GNOSIS produced no significant reduction in the interline background and the sensitivity of GNOSIS+IRIS2 is about the same as IRIS2. It is unclear whether the lack of reduction in the interline background is due to physical sources or systematic errors as the observations are detector noise dominated. OH suppression fibers could potentially impact ground-based astronomy at the level of adaptive optics or greater. However, until a

  7. Detailed characterization of a Comparative Reactivity Method (CRM) instrument for ambient OH reactivity measurements: experiments vs. modeling

    Science.gov (United States)

    Michoud, Vincent; Locoge, Nadine; Dusanter, Sébastien

    2015-04-01

    The Hydroxyl radical (OH) is the main daytime oxidant in the troposphere, leading to the oxidation of Volatile Organic Compounds (VOCs) and the formation of harmful pollutants such as ozone (O3) and Secondary Organic Aerosols (SOA). While OH plays a key role in tropospheric chemistry, recent studies have highlighted that there are still uncertainties associated with the OH budget, i.e the identification of sources and sinks and the quantification of production and loss rates of this radical. It has been demonstrated that ambient measurements of the total OH loss rate (also called total OH reactivity) can be used to identify and reduce these uncertainties. In this context, the Comparative Reactivity Method (CRM), developed by Sinha et al. (ACP, 2008), is a promising technique to measure total OH reactivity in ambient air and has already been used during several field campaigns. This technique relies on monitoring competitive reactions of OH with ambient trace gases and a reference compound (pyrrole) in a sampling reactor to derive ambient OH reactivity. However, this technique requires a complex data processing chain that has yet to be carefully investigated in the laboratory. In this study, we present a detailed characterization of a CRM instrument developed at Mines Douai, France. Experiments have been performed to investigate the dependence of the CRM response on humidity, ambient NOx levels, and the pyrrole-to-OH ratio inside the sampling reactor. Box modelling of the chemistry occurring in the reactor has also been performed to assess our theoretical understanding of the CRM measurement. This work shows that the CRM response is sensitive to both humidity and NOx, which can be accounted for during data processing using parameterizations depending on the pyrrole-to-OH ratio. The agreement observed between laboratory studies and model results suggests a good understanding of the chemistry occurring in the sampling reactor and gives confidence in the CRM

  8. HIGH PRECISION ROVIBRATIONAL SPECTROSCOPY OF OH{sup +}

    Energy Technology Data Exchange (ETDEWEB)

    Markus, Charles R.; Hodges, James N.; Perry, Adam J.; Kocheril, G. Stephen; McCall, Benjamin J. [Department of Chemistry, University of Illinois, Urbana, IL 61801 (United States); Müller, Holger S. P., E-mail: bjmccall@illinois.edu [I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln (Germany)

    2016-02-01

    The molecular ion OH{sup +} has long been known to be an important component of the interstellar medium. Its relative abundance can be used to indirectly measure cosmic ray ionization rates of hydrogen, and it is the first intermediate in the interstellar formation of water. To date, only a limited number of pure rotational transitions have been observed in the laboratory making it necessary to indirectly calculate rotational levels from high-precision rovibrational spectroscopy. We have remeasured 30 transitions in the fundamental band with MHz-level precision, in order to enable the prediction of a THz spectrum of OH{sup +}. The ions were produced in a water cooled discharge of O{sub 2}, H{sub 2}, and He, and the rovibrational transitions were measured with the technique Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy. These values have been included in a global fit of field free data to a {sup 3}Σ{sup −} linear molecule effective Hamiltonian to determine improved spectroscopic parameters which were used to predict the pure rotational transition frequencies.

  9. Comprehensive measurements of atmospheric OH reactivity and trace species within a suburban forest near Tokyo during AQUAS-TAMA campaign

    Science.gov (United States)

    Ramasamy, Sathiyamurthi; Nagai, Yoshihide; Takeuchi, Nobuhiro; Yamasaki, Shohei; Shoji, Koki; Ida, Akira; Jones, Charlotte; Tsurumaru, Hiroshi; Suzuki, Yuhi; Yoshino, Ayako; Shimada, Kojiro; Nakashima, Yoshihiro; Kato, Shungo; Hatakeyama, Shiro; Matsuda, Kazuhide; Kajii, Yoshizumi

    2018-07-01

    Total OH reactivity, which gives the instantaneous loss rate of OH radicals due to reactive species, is an invaluable technique to understand regional air quality, as it gives the overall reactivity of the air mass, the fraction of each trace species reactive to OH, the fraction of missing sinks, O3 formation potential, etc. Total OH reactivity measurement was conducted in a small suburban forest located ∼30 km from Tokyo during the air quality study at field museum TAMA (AQUAS-TAMA) campaign in early autumn 2012 and summer 2013. The average measured OH reactivities during that autumn and summer were 7.4 s-1 and 11.4 s-1, respectively. In summer, isoprene was the major contributor, accounting for 28.2% of the OH reactivity, as a result of enhanced light-dependent biogenic emission, whereas NO2 was major contributor in autumn, accounting for 19.6%, due to the diminished contribution from isoprene as a result of lower solar strength. Higher missing OH reactivity 34% was determined in summer, and linear regression analysis showed that oxygenated VOCs could be the potential candidates for missing OH reactivity. Lower missing OH reactivity 25% was determined in autumn and it was significantly reduced (11%) if the interference of peroxy radicals to the measured OH reactivity were considered.

  10. Associations between omega-3 fatty acids and 25(OH)D and psychological distress among Inuit in Canada.

    Science.gov (United States)

    Skogli, Hans-Ragnar; Geoffroy, Dominique; Weiler, Hope A; Tell, Grethe S; Kirmayer, Laurence J; Egeland, Grace M

    2017-01-01

    fatty acids; PUFAs: polyunsaturated fatty acids; 25(OH)D: 25-hydroxyvitamin D; IPY: International Polar Year; IHS : Inuit Health Survey; RBC: red blood cell; OR: odds ratio; K6: Kessler 6-item screening scale; SPD: serious psychological distress; EPA: eicosapentaenoic acid (20:5 n-3); DHA: docosahexaenoic acid (22:6 n-3); DPA n-3: docosapentaenoic acid (22:5 n-3); n-3 LC-PUFAs: EPA (20:5 n-3) + DHA (22:6 n-3) + DPA (22:5 n-3); BMI: body mass index (kg m - 2 ).

  11. Overtone spectroscopy of the hydroxyl stretch vibration in hydroxylamine (NH2OH)

    International Nuclear Information System (INIS)

    Scott, J.L.; Luckhaus, D.; Brown, S.S.; Crim, F.F.

    1995-01-01

    We present photoacoustic spectra of the second (3ν OH ), third (4ν OH ), and fourth (5ν OH ) overtone bands of the hydroxyl stretch vibration in hydroxylamine. Asymmetric rotor simulations of the rovibrational contours provide rotational constants and an estimate of the homogeneous linewidth. The fourth overtone band appears anomalously broad relative to the two lower bands, reflecting a sharp increase in the rate of intramolecular vibrational energy redistribution (IVR). By contrast, the calculated density of states increases smoothly with energy. The homogeneous linewidth of the fourth overtone transition is similar to that measured by Luo et al. [J. Chem. Phys. 93, 9194 (1990)] for the predissociative sixth overtone band, supporting the conclusion that the broadening arises from increased (ro)vibrational coupling at an energy between the third and fourth overtone states

  12. Isotope effects in the photofragmentation of symmetric molecules: The branching ratio of OD/OH in water

    DEFF Research Database (Denmark)

    Henriksen, Niels Engholm; Møller, Klaus Braagaard; Engel, Volker

    2005-01-01

    With HOD initially in its vibrational ground state, we present a new detailed interpretation of the OD/OH branching ratio (similar to 3) in the photoinduced process D+OH H+OD, in the first absorption band. Using semiclassical arguments, we show that the branching ratio has little to do...... with the initial distribution of configurations, but the initial momentum distribution plays a key role in determination of the branching ratio. The formation of D+OH arises from initial situations where OD is stretching, and it stretches faster than OH, whereas all other motions lead to H+OD. This picture...

  13. Collisional quenching of cometary emission in the 18 centimeter OH transitions

    International Nuclear Information System (INIS)

    Schloerb, F.P.

    1988-01-01

    A model of collisional quenching of the OH 2Pi(3/2) J = 3/2 Lambda doublet in cometary comae is presented. It is found that collisions with ions and electrons in the outer coma have a strong quenching effect on the Swings-effect inversion of the Lambda doublet that is responsible for the OH radio emission at 18 cm wavelength. For the conditions of Halley's comet, collisional quenching should lead radio observers to systematically underestimate the OH parent production rate by a factor of approximately 3 relative to its actual value, and in general, radio-derived production rates should always be less than or equal to UV-derived production rates, which are relatively unaffected by this process. The observation that UV production rates exceed those derived by radio techniques is well known; the direct measurement of this ratio, using a consistent coma model, should provide information about the ion and electron content of the cometary coma. 22 references

  14. SABER Observations of the OH Meinel Airglow Variability Near the Mesopause

    Science.gov (United States)

    Marsh, Daniel R.; Smith, Anne K.; Mlynczak, Martin G.

    2005-01-01

    The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument, one of four on board the TIMED satellite, observes the OH Meinel emission at 2.0 m that peaks near the mesopause. The emission results from reactions between members of the oxygen and hydrogen chemical families that can be significantly affected by mesopause dynamics. In this study we compare SABER measurements of OH Meinel emission rates and temperatures with predictions from a 3-dimensional chemical dynamical model. In general, the model is capable of reproducing both the observed diurnal and seasonal OH Meinel emission variability. The results indicate that the diurnal tide has a large effect on the overall magnitude and temporal variation of the emission in low latitudes. This tidal variability is so dominant that the seasonal cycle in the nighttime emission depends very strongly on the local time of the analysis. At higher latitudes, the emission has an annual cycle that is due mainly to transport of oxygen by the seasonally reversing mean circulation.

  15. OHS Helps Protect Employees During Flu Season | Poster

    Science.gov (United States)

    Flu season is in full swing, bringing a host of symptoms like congestion, coughs, fever, chills, muscle aches, and fatigue. To help NCI at Frederick employees stay healthy this year, Occupational Health Services (OHS) is offering two types of flu vaccines for free.

  16. On satellite lines anomalies in OH excited states

    International Nuclear Information System (INIS)

    Elitzur, M.

    1976-01-01

    It is argued that different pumps produce similar distributions of populations in the first two excited states of OH. The pattern observed recently in G 219.3 - 07 by Whiteoak and Gardner can be due either to radiative or collisional pump. (author)

  17. Ab initio chemical kinetics for the HCCO + OH reaction

    Science.gov (United States)

    Mai, Tam V.-T.; Raghunath, P.; Le, Xuan T.; Huynh, Lam K.; Nam, Pham-Cam; Lin, M. C.

    2014-01-01

    The mechanism for the reaction of HCCO and OH has been investigated at different high-levels of theory. The reaction was found to occur on singlet and triplet potential energy surfaces with multiple accessible paths. Rate constants predicted by variational RRKM/ME calculations show that the reaction on both surfaces occurs primarily by barrierless OH attack at both C atoms producing excited intermediates which fragment to produce predominantly CO and 1,3HCOH with kS = 3.12 × 10-8T-0.59exp[-73.0/T] and kT = 6.29 × 10-11T0.13exp[108/T] cm3 molecule-1 s-1 at T = 300-2000 K, independent of pressure at P < 76 000 Torr.

  18. From employee representation to problem-solving: Mainstreaming OHS management

    DEFF Research Database (Denmark)

    Hasle, Peter; Seim, Rikke; Refslund, Bjarke

    2016-01-01

    . The role of OHS representatives has accordingly changed to focus on solving specific problems in the workplace as an integrated part of daily operations. Both management and colleagues consider the OHS representatives as a resource that can be utilized to manage the work environment. The consequences......The role of occupational health and safety representatives is changing. A study in 60 Danish enterprises indicates that representation, and especially negotiation on behalf of colleagues, has diminished. The work environment is mainstreamed in many enterprises and is rarely an area of conflict...... of this development for the employees may be a stronger joint management–employee effort to improve the work environment, but also management domination and an accordingly weaker employee voice in some companies....

  19. OH masers associated with IRAS point sources

    NARCIS (Netherlands)

    Masheder, MRW; Cohen, RJ; Martin-Hernandez, NL; Migenes,; Reid, MJ

    2002-01-01

    We report a search for masers from the Lambda-doublet of the ground-state of OH at 18cm, carried out with the Jodrell Bank Lovell Telescope and with the 25m Dwingeloo telescope. All objects north of delta = -20degrees which appear in the IRAS Point Source Catalog with fluxes > 1000 Jy at 60mum and

  20. Characterization of Diesel and Gasoline Compression Ignition Combustion in a Rapid Compression-Expansion Machine using OH* Chemiluminescence Imaging

    Science.gov (United States)

    Krishnan, Sundar Rajan; Srinivasan, Kalyan Kumar; Stegmeir, Matthew

    2015-11-01

    Direct-injection compression ignition combustion of diesel and gasoline were studied in a rapid compression-expansion machine (RCEM) using high-speed OH* chemiluminescence imaging. The RCEM (bore = 84 mm, stroke = 110-250 mm) was used to simulate engine-like operating conditions at the start of fuel injection. The fuels were supplied by a high-pressure fuel cart with an air-over-fuel pressure amplification system capable of providing fuel injection pressures up to 2000 bar. A production diesel fuel injector was modified to provide a single fuel spray for both diesel and gasoline operation. Time-resolved combustion pressure in the RCEM was measured using a Kistler piezoelectric pressure transducer mounted on the cylinder head and the instantaneous piston displacement was measured using an inductive linear displacement sensor (0.05 mm resolution). Time-resolved, line-of-sight OH* chemiluminescence images were obtained using a Phantom V611 CMOS camera (20.9 kHz @ 512 x 512 pixel resolution, ~ 48 μs time resolution) coupled with a short wave pass filter (cut-off ~ 348 nm). The instantaneous OH* distributions, which indicate high temperature flame regions within the combustion chamber, were used to discern the characteristic differences between diesel and gasoline compression ignition combustion. The authors gratefully acknowledge facilities support for the present work from the Energy Institute at Mississippi State University.

  1. Exposure to a PBDE/OH-BDE mixture alters juvenile zebrafish (Danio rerio) development.

    Science.gov (United States)

    Macaulay, Laura J; Chernick, Melissa; Chen, Albert; Hinton, David E; Bailey, Jordan M; Kullman, Seth W; Levin, Edward D; Stapleton, Heather M

    2017-01-01

    Polybrominated diphenyl ethers (PBDEs) and their metabolites (e.g., hydroxylated BDEs [OH-BDEs]) are contaminants frequently detected together in human tissues and are structurally similar to thyroid hormones. Thyroid hormones partially mediate metamorphic transitions between life stages in zebrafish, making this a critical developmental window that may be vulnerable to chemicals disrupting thyroid signaling. In the present study, zebrafish were exposed to 6-OH-BDE-47 (30 nM; 15 μg/L) alone, or to a low-dose (30 μg/L) or high-dose (600 μg/L) mixture of PentaBDEs, 6-OH-BDE-47 (0.5-6 μg/L), and 2,4,6-tribromophenol (5-100 μg/L) during juvenile development (9-23 d postfertilization) and evaluated for developmental endpoints mediated by thyroid hormone signaling. Fish were sampled at 3 time points and examined for developmental and skeletal morphology, apical thyroid and skeletal gene markers, and modifications in swimming behavior (as adults). Exposure to the high-dose mixture resulted in >85% mortality within 1 wk of exposure, despite being below reported acute toxicity thresholds for individual congeners. The low-dose mixture and 6-OH-BDE-47 groups exhibited reductions in body length and delayed maturation, specifically relating to swim bladder, fin, and pigmentation development. Reduced skeletal ossification was also observed in 6-OH-BDE-47-treated fish. Assessment of thyroid and osteochondral gene regulatory networks demonstrated significantly increased expression of genes that regulate skeletal development and thyroid hormones. Overall, these results indicate that exposures to PBDE/OH-BDE mixtures adversely impact zebrafish maturation during metamorphosis. Environ Toxicol Chem 2017;36:36-48. © 2016 SETAC. © 2016 SETAC.

  2. Magnetostructural correlations in the antiferromagnetic Co2-x Cux(OH)AsO4 (x=0 and 0.3) phases

    International Nuclear Information System (INIS)

    Pedro, I. de; Rojo, J.M.; Pizarro, J.L.; Rodriguez Fernandez, J.; Arriortua, M.I.; Rojo, T.

    2011-01-01

    The Co 2-x Cu x (OH)AsO 4 (x=0 and 0.3) compounds have been synthesized under mild hydrothermal conditions and characterized by X-ray single-crystal diffraction and spectroscopic data. The hydroxi-arsenate phases crystallize in the Pnnm orthorhombic space group with Z=4 and the unit-cell parameters are a=8.277(2) A, b=8.559(2) A, c=6.039(1) A and a=8.316(1) A, b=8.523(2) A, c=6.047(1) A for x=0 and 0.3, respectively. The crystal structure consists of a three-dimensional framework in which M(1)O 5 -trigonal bipyramid dimers and M(2)O 6 -octahedral chains (M=Co and Cu) are present. Co 2 (OH)AsO 4 shows an anomalous three-dimensional antiferromagnetic ordering influenced by the magnetic field below 21 K within the presence of a ferromagnetic component below the ordering temperature. When Co 2+ is partially substituted by Cu 2+ ions, Co 1.7 Cu 0.3 (OH)AsO 4 , the ferromagnetic component observed in Co 2 (OH)AsO 4 disappears and the antiferromagnetic order is maintained in the entire temperature range. Heat capacity measurements show an unusual magnetic field dependence of the antiferromagnetic transitions. This λ-type anomaly associated to the three-dimensional antiferromagnetic ordering grows with the magnetic field and becomes better defined as observed in the non-substituted phase. These results are attributed to the presence of the unpaired electron in the dx 2 -y 2 orbital and the absence of overlap between neighbour ions. - Graphical abstract: Schematic drawing of the Co 2-x Cu x (OH)AsO 4 (x=0 and 0.3) crystal structure view along the |0 1 0| direction. Polyhedra are occupied by the M(II) ions (M=Co and Cu) and the AsO 4 groups are represented by tetrahedra. Open circles correspond to the oxygen atoms, and small circles show the hydrogen atoms. Highlights: → Synthesis of a new adamite-type compound, Co 1.7 Cu 0.3 (OH)AsO 4 . → Single crystal structure, spectroscopic characterization and magnetic properties. → Unusual dependence on the magnetic field for

  3. High-temperature rate constant measurements for OH+xylenes

    KAUST Repository

    Elwardani, Ahmed Elsaid

    2015-06-01

    The overall rate constants for the reactions of hydroxyl (OH) radicals with o-xylene (k 1), m-xylene (k 2), and p-xylene (k 3) were measured behind reflected shock waves over 890-1406K at pressures of 1.3-1.8atm using OH laser absorption near 306.7nm. Measurements were performed under pseudo-first-order conditions. The measured rate constants, inferred using a mechanism-fitting approach, can be expressed in Arrhenius form as:k1=2.93×1013exp(-1350.3/T)cm3mol-1s-1(890-1406K)k2=3.49×1013exp(-1449.3/T)cm3mol-1s-1(906-1391K)k3=3.5×1013exp(-1407.5/T)cm3mol-1s-1(908-1383K)This paper presents, to our knowledge, first high-temperature measurements of the rate constants of the reactions of xylene isomers with OH radicals. Low-temperature rate-constant measurements by Nicovich et al. (1981) were combined with the measurements in this study to obtain the following Arrhenius expressions, which are applicable over a wider temperature range:k1=2.64×1013exp(-1181.5/T)cm3mol-1s-1(508-1406K)k2=3.05×109exp(-400/T)cm3mol-1s-1(508-1391K)k3=3.0×109exp(-440/T)cm3mol-1s-1(526-1383K) © 2015 The Combustion Institute.

  4. The Development of Danish OHS Regulation - Organizational Understanding and Program Theory

    DEFF Research Database (Denmark)

    Seim, Rikke; Jensen, Per Langaa; Møller, Niels

    2014-01-01

    in organizing OHS, 3) link between the companies’ overall strategic management and OHS and 4) continuously competence development for the health and safety representatives. In this paper we present and analyze the individual elements of the legislative amendment. Subsequent we investigate the organizational......This paper focuses on a major recent amendment of the Danish Working Environment regulation concerning the cooperation of health and safety between employees and employer. The amendment, which came into force in October 2010, consists of four elements: 1) change of terminology, 2) flexibility...

  5. Ca(2+) and OH(-) release of ceramsites containing anorthite and gehlenite prepared from waste lime mud.

    Science.gov (United States)

    Qin, Juan; Yang, Chuanmeng; Cui, Chong; Huang, Jiantao; Hussain, Ahmad; Ma, Hailong

    2016-09-01

    Lime mud is a kind of solid waste in the papermaking industry, which has been a source of serious environmental pollution. Ceramsites containing anorthite and gehlenite were prepared from lime mud and fly ash through the solid state reaction method at 1050°C. The objective of this study was to explore the efficiency of Ca(2+) and OH(-) release and assess the phosphorus and copper ion removal performance of the ceramsites via batch experiments, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that Ca(2+) and OH(-) were released from the ceramsites due to the dissolution of anorthite, gehlenite and available lime. It is also concluded that gehlenite had stronger capacity for Ca(2+) and OH(-) release compared with anorthite. The Ca(2+) release could be fit well by the Avrami kinetic model. Increases of porosity, dosage and temperature were associated with increases in the concentrations of Ca(2+) and OH(-) released. Under different conditions, the ceramsites could maintain aqueous solutions in alkaline conditions (pH=9.3-10.9) and the release of Ca(2+) was not affected. The removal rates of phosphorus and copper ions were as high as 96.88% and 96.81%, respectively. The final pH values of both phosphorus and copper ions solutions changed slightly. The reuse of lime mud in the form of ceramsites is an effective strategy. Copyright © 2016. Published by Elsevier B.V.

  6. Hydrothermal Formation of the Head-to-Head Coalesced Szaibelyite MgBO2(OH Nanowires

    Directory of Open Access Journals (Sweden)

    Zhu Wancheng

    2009-01-01

    Full Text Available Abstract The significant effect of the feeding mode on the morphology and size distribution of the hydrothermal synthesized MgBO2(OH is investigated, which indicates that, slow dropping rate (0.5 drop s−1 and small droplet size (0.02 mL d−1 of the dropwise added NaOH solution are favorable for promoting the one-dimensional (1D preferential growth and thus enlarging the aspect ratio of the 1D MgBO2(OH nanostructures. The joint effect of the low concentration of the reactants and feeding mode on the hydrothermal product results in the head-to-head coalesced MgBO2(OH nanowires with a length of 0.5–9.0 μm, a diameter of 20–70 nm, and an aspect ratio of 20–300 in absence of any capping reagents/surfactants or seeds.

  7. The Attitude of Construction Workers toward the Implementation of Occupational Health and Safety (OHS)

    Science.gov (United States)

    Widaningsih, L.; Susanti, I.; Chandra, T.

    2018-02-01

    Construction industry refers to one of the industries dealing with high accident rate. Besides its outdoor workplace involving many workers who usually work manually, the workers’ work culture and less awareness of occupational health and safety (OHS) are attributed to the high accident rate. This study explores some construction workers who are involved in some construction projects in big cities such as Bandung and Jakarta. The questionnaire-given to the construction workers focusing on stone construction, wood construction, and finishing session-reveals that the construction workers knowledge and understanding of nine Occupational Health and Safety (OHS) aspects reach above 50%. However, does not appear to reflect their knowledge and understanding of Occupational Health and Safety (OHS). The results of Focus Group Discussion (FGD) and an in-depth interview show that the fallacious implementation of Occupational Health and Safety (OHS) is attributed to their traditional “work culture”.

  8. Determination of the rate constant for the OH(X2Π) + OH(X2Π) → H2O + O(3P) reaction over the temperature range 295 to 701 K.

    Science.gov (United States)

    Altinay, Gokhan; Macdonald, R Glen

    2014-01-09

    The rate constant for the radical-radical reaction OH(X(2)Π) + OH(X(2)Π) → H2O + O((3)P) has been measured over the temperature and pressure ranges 295-701 K and 2-12 Torr, respectively, in mixtures of CF4, N2O, and H2O. The OH radical was produced by the 193 nm laser photolysis of N2O. The resulting O((1)D) atoms reacted rapidly with H2O to produce the OH radical. The OH radical was detected by high-resolution time-resolved infrared absorption spectroscopy using a single Λ-doublet component of the OH(1,0) P1e/f(4.5) fundamental vibrational transition. A detailed kinetic model was used to determine the reaction rate constant as a function of temperature. These experiments were conducted in a new temperature controlled reaction chamber. The values of the measured rate constants are quite similar to the previous measurements from this laboratory of Bahng and Macdonald (J. Phys. Chem. A 2007 , 111 , 3850 - 3861); however, they cover a much larger temperature range. The results of the present work do not agree with recent measurements of Sangwan and Krasnoperov (J. Phys. Chem. A 2012 , 116 , 11817 - 11822). At 295 K the rate constant of the title reaction was found to be (2.52 ± 0.63) × 10(-12) cm(3) molecule(-1) s(-1), where the uncertainty includes both experimental scatter and an estimate of systematic errors at the 95% confidence limit. Over the temperature range of the experiments, the rate constant can be represented by k1a = 4.79 × 10(-18)T(1.79) exp(879.0/T) cm(3) molecule(-1) s(-1) with a uncertainty of ±24% at the 2σ level, including experimental scatter and systematic error.

  9. Fluorescence branching ratios and magnetic tuning of the visible spectrum of SrOH

    Science.gov (United States)

    Nguyen, Duc-Trung; Steimle, Timothy C.; Kozyryev, Ivan; Huang, Meng; McCoy, Anne B.

    2018-05-01

    The magnetic tuning of the low rotational levels in the X ˜ 2Σ+ (0,0,0), A ˜ 2Πr (0,0,0), and B ˜ 2Σ+ (0,0,0) electronic states of strontium hydroxide, SrOH, have been experimentally investigated using high resolution optical field-free and Zeeman spectroscopy of a cold molecular beam sample. The observed Zeeman shifts and splittings are successfully modeled using a traditional effective Hamiltonian approach to account for the interaction between the A ˜ 2Πr and B ˜ 2Σ+ states. The determined magnetic g-factors for the X ˜ 2Σ+ , A ˜ 2Πr , and B ˜ 2Σ+ states are compared to those predicted by perturbation theory. The dispersed fluorescence resulting from laser excitation of rotationally resolved branch features of the 000 B ˜ 2Σ+ ← X ˜ 2Σ+ , 000 A ˜ 2Π3/2 ← X ˜ 2Σ+ and 000 A ˜ 2Π1/2 ← X ˜ 2Σ+ transitions have been recorded and analyzed. The measured fluorescence branching ratios are compared with Franck-Condon calculations. The required bending motion wave functions are derived using a discrete variable representation (DVR) method. Implications for laser slowing and magneto-optical trapping experiments for SrOH are described.

  10. A Shock Tube Study of the CO + OH Reaction Near the Low-Pressure Limit

    KAUST Repository

    Nasir, Ehson Fawad; Farooq, Aamir

    2016-01-01

    Rate coefficients for the reaction between carbon monoxide and hydroxyl radical were measured behind reflected shock waves over 700 – 1230 K and 1.2 – 9.8 bar. The temperature/pressure conditions correspond to the predicted low-pressure limit of this reaction, where the channel leading to carbon dioxide formation is dominant. The reaction rate coefficients were inferred by measuring the formation of carbon dioxide using quantum cascade laser absorption near 4.2 µm. Experiments were performed under pseudo-first order conditions with tert-butyl hydroperoxide (TBHP) as the OH precursor. Using ultraviolet laser absorption by OH radicals, the TBHP decomposition rate was measured to quantify potential facility effects under extremely dilute conditions used here. The measured CO + OH rate coefficients are provided in Arrhenius form for three different pressure ranges: kCO+OH (1.2 – 1.6 bar) = 9.14 x 10-13 exp(-1265/T) cm3 molecule-1 s-1 kCO+OH (4.3 – 5.1 bar) = 8.70 x 10-13 exp(-1156/T) cm3 molecule-1 s-1 kCO+OH (9.6 – 9.8 bar) = 7.48 x 10-13 exp(-929/T) cm3 molecule-1 s-1 The measured rate coefficients are found to be lower than the master equation modeling results by Weston et al. [J. Phys. Chem. A, 117 (2013) 821] at 819 K and in closer agreement with the expression provided by Joshi and Wang [Int. J. Chem. Kinet., 38 (2006) 57].

  11. Near-UV OH Prompt Emission in the Innermost Coma of 103P/Hartley 2

    Science.gov (United States)

    La Forgia, Fiorangela; Bodewits, Dennis; A'Hearn, Michael F.; Protopapa, Silvia; Kelley, Michael S. P.; Sunshine, Jessica; Feaga, Lori; Farnham, Tony

    2017-11-01

    The Deep Impact spacecraft flyby of comet 103P/Hartley 2 occurred on 2010 November 4, 1 week after perihelion with a closest approach (CA) distance of about 700 km. We used narrowband images obtained by the Medium Resolution Imager on board the spacecraft to study the gas and dust in the innermost coma. We derived an overall dust reddening of 15%/100 nm between 345 and 749 nm and identified a blue enhancement in the dust coma in the sunward direction within 5 km from the nucleus, which we interpret as a localized enrichment in water ice. OH column density maps show an anti-sunward enhancement throughout the encounter, except for the highest-resolution images, acquired at CA, where a radial jet becomes visible in the innermost coma, extending up to 12 km from the nucleus. The OH distribution in the inner coma is very different from that expected for a fragment species. Instead, it correlates well with the water vapor map derived by the HRI-IR instrument on board Deep Impact. Radial profiles of the OH column density and derived water production rates show an excess of OH emission during CA that cannot be explained with pure fluorescence. We attribute this excess to a prompt emission process where photodissociation of H2O directly produces excited OH*(A 2Σ+) radicals. Our observations provide the first direct imaging of near-UV prompt emission of OH. We therefore suggest the use of a dedicated filter centered at 318.8 nm to directly trace the water in the coma of comets.

  12. A Shock Tube Study of the CO + OH Reaction Near the Low-Pressure Limit

    KAUST Repository

    Nasir, Ehson Fawad

    2016-05-16

    Rate coefficients for the reaction between carbon monoxide and hydroxyl radical were measured behind reflected shock waves over 700 – 1230 K and 1.2 – 9.8 bar. The temperature/pressure conditions correspond to the predicted low-pressure limit of this reaction, where the channel leading to carbon dioxide formation is dominant. The reaction rate coefficients were inferred by measuring the formation of carbon dioxide using quantum cascade laser absorption near 4.2 µm. Experiments were performed under pseudo-first order conditions with tert-butyl hydroperoxide (TBHP) as the OH precursor. Using ultraviolet laser absorption by OH radicals, the TBHP decomposition rate was measured to quantify potential facility effects under extremely dilute conditions used here. The measured CO + OH rate coefficients are provided in Arrhenius form for three different pressure ranges: kCO+OH (1.2 – 1.6 bar) = 9.14 x 10-13 exp(-1265/T) cm3 molecule-1 s-1 kCO+OH (4.3 – 5.1 bar) = 8.70 x 10-13 exp(-1156/T) cm3 molecule-1 s-1 kCO+OH (9.6 – 9.8 bar) = 7.48 x 10-13 exp(-929/T) cm3 molecule-1 s-1 The measured rate coefficients are found to be lower than the master equation modeling results by Weston et al. [J. Phys. Chem. A, 117 (2013) 821] at 819 K and in closer agreement with the expression provided by Joshi and Wang [Int. J. Chem. Kinet., 38 (2006) 57].

  13. Systems Li[sub 2]B[sub 4]O[sub 7] (Na[sub 2]B[sub 4]O[sub 7], K[sub 2]B[sub 4]O[sub 7])-N[sub 2]H[sub 3]H[sub 4]OH-H[sub 2]O at 25 deg C. Sistemy Li[sub 2]B[sub 4]O[sub 7] (Na[sub 2]B[sub 4]O[sub 7], K[sub 2]B[sub 4]O[sub 7])-N[sub 2]H[sub 3]H[sub 4]OH-H[sub 2]O pri 25 grad S

    Energy Technology Data Exchange (ETDEWEB)

    Skvortsov, V G; Sadetdinov, Sh V; Akimov, V M; Mitrasov, Yu N; Petrova, O V; Klopov, Yu N [Chuvashskij Gosudarstvennyj Pedagogicheskij Inst., Cheboksary (Russian Federation) Universitet Druzhby Narodov, Moscow (Russian Federation)

    1994-02-01

    Phase equilibriums in the Li[sub 2]B[sub 4]O[sub 7] (Na[sub 2]B[sub 4]O[sub 7], K[sub 2]B[sub 4]O[sub 7])-N[sub 2]H[sub 3]H[sub 4]OH-H[sub 2]O systems were investigated by methods of isothermal solubility, refractometry and PH-metry at 25 deg C for the first time. Lithium and sodium tetraborates was established to form phases of changed composition mM[sub 2]B[sub 4]O[sub 7][center dot]nN[sub 2]H[sub 3]C[sub 2]H[sub 4]OH[center dot]XH[sub 2]O, where M=Li, Na with hydrazine ethanol. K[sub 2]B[sub 4]O[sub 7][center dot]4H[sub 2]O precipitates in solid phase in the case of potassium salt. Formation of isomorphous mixtures was supported by X-ray diffraction and IR spectroscopy methods.

  14. Comparison of OH reactivity measurements in the atmospheric simulation chamber SAPHIR

    Science.gov (United States)

    Fuchs, Hendrik; Novelli, Anna; Rolletter, Michael; Hofzumahaus, Andreas; Pfannerstill, Eva Y.; Kessel, Stephan; Edtbauer, Achim; Williams, Jonathan; Michoud, Vincent; Dusanter, Sebastien; Locoge, Nadine; Zannoni, Nora; Gros, Valerie; Truong, Francois; Sarda-Esteve, Roland; Cryer, Danny R.; Brumby, Charlotte A.; Whalley, Lisa K.; Stone, Daniel; Seakins, Paul W.; Heard, Dwayne E.; Schoemaecker, Coralie; Blocquet, Marion; Coudert, Sebastien; Batut, Sebastien; Fittschen, Christa; Thames, Alexander B.; Brune, William H.; Ernest, Cheryl; Harder, Hartwig; Muller, Jennifer B. A.; Elste, Thomas; Kubistin, Dagmar; Andres, Stefanie; Bohn, Birger; Hohaus, Thorsten; Holland, Frank; Li, Xin; Rohrer, Franz; Kiendler-Scharr, Astrid; Tillmann, Ralf; Wegener, Robert; Yu, Zhujun; Zou, Qi; Wahner, Andreas

    2017-10-01

    Hydroxyl (OH) radical reactivity (kOH) has been measured for 18 years with different measurement techniques. In order to compare the performances of instruments deployed in the field, two campaigns were conducted performing experiments in the atmospheric simulation chamber SAPHIR at Forschungszentrum Jülich in October 2015 and April 2016. Chemical conditions were chosen either to be representative of the atmosphere or to test potential limitations of instruments. All types of instruments that are currently used for atmospheric measurements were used in one of the two campaigns. The results of these campaigns demonstrate that OH reactivity can be accurately measured for a wide range of atmospherically relevant chemical conditions (e.g. water vapour, nitrogen oxides, various organic compounds) by all instruments. The precision of the measurements (limit of detection CRM) has a higher limit of detection of 2 s-1 at a time resolution of 10 to 15 min. The performances of the instruments were systematically tested by stepwise increasing, for example, the concentrations of carbon monoxide (CO), water vapour or nitric oxide (NO). In further experiments, mixtures of organic reactants were injected into the chamber to simulate urban and forested environments. Overall, the results show that the instruments are capable of measuring OH reactivity in the presence of CO, alkanes, alkenes and aromatic compounds. The transmission efficiency in Teflon inlet lines could have introduced systematic errors in measurements for low-volatile organic compounds in some instruments. CRM instruments exhibited a larger scatter in the data compared to the other instruments. The largest differences to reference measurements or to calculated reactivity were observed by CRM instruments in the presence of terpenes and oxygenated organic compounds (mixing ratio of OH reactants were up to 10 ppbv). In some of these experiments, only a small fraction of the reactivity is detected. The accuracy of CRM

  15. Correlation between follicular fluid 25-OH vitamin D and assisted reproductive outcomes

    Directory of Open Access Journals (Sweden)

    Laya Farzadi

    2015-06-01

    Full Text Available Background: Vitamin D in complex with its receptor by regulating gene expression, endometrium immune response and stimulation of endometrium decidualization can be involved in implantation. So, it seems that the amount of vitamin D in follicular fluids (FF may have an association with ART success. Objective: First, we intended to investigate the possible association between levels of follicular fluids 25-OH vitamin D with assisted reproductive outcomes. Second, we examined relationship between 25-OH vitamin D levels with number and quality of oocytes. Materials and Methods: In a prospective study, 80 infertile female candidates for IVF/ICSI were enrolled. Blood samples (on the day of human chorionic gonadotropin administration and follicular fluids were taken, and then levels of serum estradiol and follicular fluids 25-OH vitamin D were measured. Also clinical characteristics of patients (duration of infertility, causes of infertility, menstrual status, number and quality of oocytes, number of fertilized oocytes, estradiol levels, and clinical pregnancy were evaluated. Results: Concentration of FF 25-OH vitamin D in pregnant women was significantly higher than non-pregnant women (p=0.007 but there were no significant differences in age, body mass index (BMI, duration of infertility, menstrual status, number of oocytes, oocytes quality, number of fertilized oocytes, and serum estradiol levels between the two groups. Statistically positive correlation was found between 25-OH vitamin D levels with patient age and implantation rate (r=0.264, p=0.018 and r=0.301, p=0.007 respectively. Conclusion: The obtained results suggest that vitamin D without affecting the number and quality of oocytes can independently improve implantation rate and IVF outcome.

  16. The Role of Mg(OH)2 in the So-Called "Base-Free" Oxidation of Glycerol with AuPd Catalysts.

    Science.gov (United States)

    Fu, Jile; He, Qian; Miedziak, Peter J; Brett, Gemma L; Huang, Xiaoyang; Pattisson, Samuel; Douthwaite, Mark; Hutchings, Graham J

    2018-02-16

    Mg(OH) 2 - and Mg(OH) 2 -containing materials can provide excellent performance as supports for AuPd nanoparticles for the oxidation of glycerol in the absence of base, which is considered to be a result of additional basic sites on the surface of the support. However, its influence on the reaction solution is not generally discussed. In this paper, we examine the relationship between the basic Mg(OH) 2 support and AuPd nanoparticles in detail using four types of catalyst. For these reactions, the physical interaction between Mg(OH) 2 and AuPd was adjusted. It was found that the activity of the AuPd nanoparticles increased with the amount of Mg(OH) 2 added under base-free conditions, regardless of its interaction with the noble metals. In order to investigate how Mg(OH) 2 affected the glycerol oxidation, detailed information about the performance of AuPd/Mg(OH) 2 , physically mixed (AuPd/C+Mg(OH) 2 ) and (AuPd/C+NaHCO 3 ) was obtained and compared. Furthermore, NaOH and Mg(OH) 2 were added during the reaction using AuPd/C. All these results indicate that the distinctive and outstanding performance of Mg(OH) 2 supported catalysts in base-free condition is in fact directly related to its ability to affect the pH during the reaction and as such, assists with the initial activation of the primary alcohol, which is considered to be the rate determining step in the reaction. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. VLA OH Zeeman Observations of the NGC 6334 Complex Source A

    Science.gov (United States)

    Mayo, E. A.; Sarma, A. P.; Troland, T. H.; Abel, N. P.

    2004-12-01

    We present a detailed analysis of the NGC 6334 complex source A, a compact continuum source in the SW region of the complex. Our intent is to determine the significance of the magnetic field in the support of the surrounding molecular cloud against gravitational collapse. We have performed OH 1665 and 1667 MHz observations taken with the Very Large Array in the BnA configuration and combined these data with the lower resolution CnB data of Sarma et al. (2000). These observations reveal magnetic fields with values of the order of 350 μ G toward source A, with maximum fields reaching 500 μ G. We have also theoretically modeled the molecular cloud surrounding source A using Cloudy, with the constraints to the model based on observation. This model provides significant information on the density of H2 through the cloud and also the relative density of H2 to OH which is important to our analysis of the region. We will combine the knowledge gained through the Cloudy modeling with Virial estimates to determine the significance of the magnetic field to the dynamics and evolution of source A.

  18. Measurement of gas temperature and OH density in the afterglow of pulsed positive corona discharge

    International Nuclear Information System (INIS)

    Ono, Ryo; Oda, Tetsuji

    2008-01-01

    The gas temperature and OH density in the afterglow of pulsed positive corona discharge are measured using the laser-induced predissociation fluorescence (LIPF) of OH radicals. Discharge occurs in a 13 mm point-to-plane gap in an atmospheric-pressure H 2 O(2.8%)/O 2 (2.0%)/N 2 mixture. The temperature measurement shows that (i) the temperature increases after discharge and (ii) the temperature near the anode tip (within 1 mm from the anode tip) is much higher than that of the rest of the discharge volume. Near the anode tip, the temperature increases from 500 K (t = 0 μs) to 1100 K (t = 20 μs), where t is the postdischarge time, while it increases from 400 K (t = 0 μs) to 700 K (t = 100 μs) in the rest of the discharge volume away from the anode tip. This temperature difference between the two volumes (near and far from the anode tip) causes a difference in the decay rate of OH density: OH density near the anode tip decays approximately 10 times slower than that far from the tip. The spatial distribution of OH density shows good agreement with that of the secondary streamer luminous intensity. This shows that OH radicals are mainly produced in the secondary streamer, not in the primary one

  19. Reactions of OH radicals with 2-methyl-1-butyl, neopentyl and 1-hexyl nitrates. Structure-activity relationship for gas-phase reactions of OH with alkyl nitrates: An update

    Science.gov (United States)

    Bedjanian, Yuri; Morin, Julien; Romanias, Manolis N.

    2018-05-01

    The kinetics of the reactions 2-methyl-1-butyl (2M1BNT), neopentyl (NPTNT) and 1-hexyl nitrates (1HXNT) with OH radicals has been studied using a low pressure flow tube reactor combined with a quadrupole mass spectrometer. The rate constants of the title reactions were determined under pseudo-first order conditions from kinetics of OH consumption in excess of nitrates. The overall rate coefficients, k2M1BNT = 1.54 × 10-14 (T/298)4.85 exp (1463/T) (T = 278-538 K), kNPTNT = 1.39 × 10-14 (T/298)4.89 exp (1189/T) (T = 278-500 K) and k1HXNT = 2.23 × 10-13 (T/298)2.83 exp (853/T) cm3molecule-1s-1 (T = 306-538 K) (with conservative 15% uncertainty), were determined at a total pressure of 1 Torr of helium. The yield of trimethylacetaldehyde ((CH3)3CCHO), resulting from the abstraction by OH of an α-hydrogen atom in neopentyl nitrate, followed by α-substituted alkyl radical decomposition, was determined as 0.31 ± 0.06 at T = 298 K. The calculated tropospheric lifetimes of 2M1BNT, NPTNT and 1HXNT indicate that reaction of these nitrates with OH represents an important sink of these compounds in the atmosphere. Based on the available kinetic data, we have updated the structure-activity relationship (SAR) for reactions of alkyl nitrates with OH at T = 298 K. Good agreement (within 20%) is obtained between experimentally measured rate constants (total and that for H-atom abstraction from α carbon) and those calculated from SAR using new substituents factors for almost all the experimental data available.

  20. Non-OH Chemistry in Oxidation Flow Reactors for the Study of Atmospheric Chemistry Systematically Examined by Modeling

    Science.gov (United States)

    Peng, Zhe; Day, Douglas A.; Ortega, Amber M.; Palm, Brett B.; Hu, Weiwei; Stark, Harald; Li, Rui; Tsigaridis, Kostas; Brune, William H.; Jimenez, Jose L.

    2016-01-01

    Oxidation flow reactors (OFRs) using low-pressure Hg lamp emission at 185 and 254 nm produce OH radicals efficiently and are widely used in atmospheric chemistry and other fields. However, knowledge of detailed OFR chemistry is limited, allowing speculation in the literature about whether some non-OH reactants, including several not relevant for tropospheric chemistry, may play an important role in these OFRs. These non-OH reactants are UV radiation, O(1D), O(3P), and O3. In this study, we investigate the relative importance of other reactants to OH for the fate of reactant species in OFR under a wide range of conditions via box modeling. The relative importance of non-OH species is less sensitive to UV light intensity than to relative humidity (RH) and external OH reactivity (OHRext), as both non-OH reactants and OH scale roughly proportional to UV intensity. We show that for field studies in forested regions and also the urban area of Los Angeles, reactants of atmospheric interest are predominantly consumed by OH. We find that O(1D), O(3P), and O3 have relative contributions to VOC consumption that are similar or lower than in the troposphere. The impact of O atoms can be neglected under most conditions in both OFR and troposphere. Under pathological OFR conditions of low RH and/or high OHRext, the importance of non-OH reactants is enhanced because OH is suppressed. Some biogenics can have substantial destructions by O3, and photolysis at non-tropospheric wavelengths (185 and 254 nm) may also play a significant role in the degradation of some aromatics under pathological conditions. Working under low O2 with the OFR185 mode allows OH to completely dominate over O3 reactions even for the biogenic species most reactive with O3. Non-tropospheric VOC photolysis may have been a problem in some laboratory and source studies, but can be avoided or lessened in future studies by diluting source emissions and working at lower precursor concentrations in lab studies, and by

  1. Integrated nanophotonic hubs based on ZnO-Tb(OH3/SiO2 nanocomposites

    Directory of Open Access Journals (Sweden)

    Lin Yu

    2011-01-01

    Full Text Available Abstract Optical integration is essential for practical application, but it remains unexplored for nanoscale devices. A newly designed nanocomposite based on ZnO semiconductor nanowires and Tb(OH3/SiO2 core/shell nanospheres has been synthesized and studied. The unique sea urchin-type morphology, bright and sharply visible emission bands of lanthanide, and large aspect ratio of ZnO crystalline nanotips make this novel composite an excellent signal receiver, waveguide, and emitter. The multifunctional composite of ZnO nanotips and Tb(OH3/SiO2 nanoparticles therefore can serve as an integrated nanophotonics hub. Moreover, the composite of ZnO nanotips deposited on a Tb(OH3/SiO2 photonic crystal can act as a directional light fountain, in which the confined radiation from Tb ions inside the photonic crystal can be well guided and escape through the ZnO nanotips. Therefore, the output emission arising from Tb ions is truly directional, and its intensity can be greatly enhanced. With highly enhanced lasing emissions in ZnO-Tb(OH3/SiO2 as well as SnO2-Tb(OH3/SiO2 nanocomposites, we demonstrate that our approach is extremely beneficial for the creation of low threshold and high-power nanolaser.

  2. Using atmospheric 14CO to constrain OH variability: concept and potential for future measurements

    Science.gov (United States)

    Petrenko, V. V.; Murray, L. T.; Smith, A. W.

    2017-12-01

    The primary source of 14C-containing carbon monoxide (14CO) in the atmosphere is via 14C production from 14N by secondary cosmic rays, and the primary sink is removal by OH. Variations in the global abundance of 14CO that are not explained by variations in 14C production are mainly driven by variations in the global abundance of OH. Monitoring OH variability via methyl chloroform is becoming increasingly difficult as methyl chloroform abundance is continuing to decline. Measurements of atmospheric 14CO have previously been successfully used to infer OH variability. However, these measurements are currently only continuing at one location (Baring Head, New Zealand), which is insufficient to infer global trends. We propose to restart global 14CO monitoring with the aim of providing another constraint on OH variability. A new analytical system for 14CO sampling and measurements is in development, which will allow to strongly reduce the required sample air volumes (previously ≥ 400 L) and simplify field logistics. A set of test measurements is planned, with sampling at the Mauna Loa Observatory. Preliminary work with a state-of-the-art chemical transport model is identifying the most promising locations for global 14CO sampling.

  3. Not flavone-8-acetic acid (FAA) but its murine metabolite 6-OH-FAA exhibits remarkable antivascular activities in vitro.

    Science.gov (United States)

    Pham, Minh Hien; Dauzonne, Daniel; Chabot, Guy G

    2016-06-01

    Flavone-8-acetic acid (FAA) has been proved to be a potent vascular-disrupting agent in mice. Unfortunately, FAA did not produce any anticancer activity in clinical trials. Previously, we had reported that FAA is metabolized by mouse microsomes into six metabolites, whereas it was poorly metabolized by human microsomes, with fewer metabolites formed in lesser amounts. Especially, 6-OH-FAA was not formed by human microsomes. In this work, two major available metabolites, 4'-OH-FAA and 6-OH-FAA, were tested and compared with the parent compound FAA for their potential antivascular activities in vitro. The ability of the products to induce morphological changes, disrupt preformed capillaries of EA.hy926 endothelial cells and inhibit tubulin polymerization in vitro was assessed. The action mechanism was determined using the RhoA and Rac1 inhibitors. At 25 µg/ml, 6-OH-FAA induced morphological changes and membrane blebbing, whereas 300 µg/ml of FAA and 4'-OH-FAA slightly changed the morphology without inducing membrane blebbing. At 300 µg/ml, 6-OH-FAA produced morphological changes that were 2.1-6.9-fold greater than that produced by FAA and 4'-OH-FAA, an effect that was consistent with its much greater inhibitory effect on tubulin polymerization compared with FAA and 4'-OH-FAA. 6-OH-FAA significantly disrupted the EA.hy926 cell capillaries. 6-OH-FAA activities were prevented in EA.hy926 cells pretreated with RhoA, but not Rac1, inhibitor. In this short communication we report for the first time that, in vitro, 6-OH-FAA, a mouse-specific FAA metabolite, exhibits significantly stronger antivascular activities compared with FAA and 4'-OH-FAA, which are mediated through the RhoA kinase pathway.

  4. Association between Obesity and Serum 25(OH)D Concentrations in Older Mexican Adults.

    Science.gov (United States)

    Rontoyanni, Victoria G; Avila, Jaqueline C; Kaul, Sapna; Wong, Rebeca; Veeranki, Sreenivas P

    2017-01-31

    Vitamin D is essential for maintaining bone mineralization and calcium homeostasis, and prevents falls and fractures in older adults. Mexico is undergoing an epidemiologic and demographic transition with increasing obesity rates. The study's aim was to determine the association of obesity with serum 25-hydroxyvitamin D [25(OH)D] concentrations in older Mexican adults. Data from 1772 Mexicans, aged ≥50 years, enrolled in a sub-sample of the 3rd wave of the Mexican Health and Aging Study, were included. Serum 25(OH)D concentrations were used to define vitamin D status, and were categorized into tertiles. Body mass index measures were used to categorize older adults into under/normal weight, overweight, and obese groups. Multinomial logistic regression models were used to assess the relationship, adjusting for potential confounders. Approximately 40% and 37% of older Mexican adults were either overweight or obese, respectively. Compared to under/normal weight older Mexicans, obese adults were 1.78 times (95% Confidence Interval (CI) 1.27-2.48) and 1.94 times (95% CI 1.40-2.68) more associated with the first and second tertile concentrations of serum 25(OH)D, respectively. Overweight adults were 1.52 times (95% CI 1.12-2.06) more associated with the second tertile of serum 25(OH)D concentration than under/normal weight adults. Overweight/Obesity was found to be significantly associated with low concentrations of serum 25(OH) in older Mexican adults.

  5. Preparation of Ni(OH){sub 2}-graphene sheet-carbon nanotube composite as electrode material for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y.F. [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); College of Environmental and Chemical Engineering, Heilongjiang University of Science and Technology, Harbin 150022 (China); Yuan, G.H., E-mail: ygh@hit.edu.cn [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Jiang, Z.H., E-mail: jiangzhaohua@hit.edu.cn [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Yao, Z.P. [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Yue, M. [Shenzhen BTR New Energy Materials INC., Shenzhen 528206 (China)

    2015-01-05

    Highlights: • CNT is introduced into graphene to prevent restacking by solvothermal reaction. • Ethanol as a low cost and green solvent is used in solvothermal reaction. • Ni(OH){sub 2} nanosheets were chemically precipitated into GS-CNT to increase the capacitance. - Abstract: Ni(OH){sub 2}-graphene sheet-carbon nanotube composite was prepared for supercapacitance materials through a simple two-step process involving solvothermal synthesis of graphene sheet-carbon nanotube composite in ethanol and chemical precipitation of Ni(OH){sub 2}. According to N{sub 2} adsorption/desorption analysis, the Brunauer–Emmett–Teller surface area of graphene sheet-carbon nanotube composite (109.07 m{sup 2} g{sup −1}) was larger than that of pure graphene sheets (32.06 m{sup 2} g{sup −1}), indicating that the added carbon nanotubes (15 wt.%) could prevent graphene sheets from restacking in the solvothermal reaction. The results of field emission scanning electron microscopy and transmission electron microscopy showed that Ni(OH){sub 2} nanosheets were uniformly loaded into the three-dimensional interconnected network of graphene sheet-carbon nanotube composite. The microstructure enhanced the rate capability and utilization of Ni(OH){sub 2}. The specific capacitance of Ni(OH){sub 2}-graphene sheet-carbon nanotube composite was 1170.38 F g{sup −1} at a current density of 0.2 A g{sup −1} in the 6 mol L{sup −1} KOH solution, higher than those provided by pure Ni(OH){sub 2} (953.67 Fg{sup −1}) and graphene sheets (178.25 F g{sup −1}). After 20 cycles at each current density (0.2, 0.4, 0.6, 0.8, 1.0 and 1.2 A g{sup −1}), the capacitance of Ni(OH){sub 2}-graphene sheet-carbon nanotube composite decreased 26.96% of initial capacitance compared to 74.52% for pure Ni(OH){sub 2}.

  6. Hierarchical Co(OH)_2 nanostructures/glassy carbon electrode derived from Co(BTC) metal–organic frameworks for glucose sensing

    International Nuclear Information System (INIS)

    He, Juan; Lu, Xingping; Yu, Jie; Wang, Li; Song, Yonghai

    2016-01-01

    A novel Co(OH)_2/glassy carbon electrode (GCE) has been fabricated via metal–organic framework (MOF)-directed method. In the strategy, the Co(BTC, 1,3,5-benzentricarboxylic acid) MOFs/GCE was firstly prepared by alternately immersing GCE in Co"2"+ and BTC solution based on a layer-by-layer method. And then, the Co(OH)_2 with hierarchical flake nanostructure/GCE was constructed by immersing Co(BTC) MOFs/GCE into 0.1 M NaOH solution at room temperature. Such strategy improves the distribution of hierarchical Co(OH)_2 nanostructures on electrode surface greatly, enhances the stability of nanomaterials on the electrode surface, and increases the use efficiency of the Co(OH)_2 nanostructures. Scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray powder diffraction, energy dispersive spectroscopy, Fourier transform infrared spectroscopy, and Raman spectra were used to characterize the Co(BTC) MOFs/GCE and Co(OH)_2/GCE. Based on the hierarchical Co(OH)_2 nanostructures/GCE, a novel and sensitive nonenzymatic glucose sensor was developed. The good performance of the resulted sensor toward the detection of glucose was ascribed to hierarchical flake nanostructures, good mechanical stability, excellent distribution, and large specific surface area of Co(OH)_2 nanostructures. The proposed preparation method is simple, efficient, and cheap .Graphical Abstract.

  7. Facile Synthesis of SrCO3-Sr(OH2/PPy Nanocomposite with Enhanced Photocatalytic Activity under Visible Light

    Directory of Open Access Journals (Sweden)

    Alfredo Márquez-Herrera

    2016-01-01

    Full Text Available Pyrrole monomer was chemically polymerized onto SrCO3-Sr(OH2 powders to obtain SrCO3-Sr(OH2/polypyrrole nanocomposite to be used as a candidate for photocatalytic degradation of methylene blue dye (MB. The material was characterized by Fourier transform infrared (FTIR spectroscopy, UV/Vis spectroscopy, and X-ray diffraction (XRD. It was observed from transmission electronic microscopy (TEM analysis that the reported synthesis route allows the production of SrCO3-Sr(OH2 nanoparticles with particle size below 100 nm which were embedded within a semiconducting polypyrrole matrix (PPy. The SrCO3-Sr(OH2 and SrCO3-Sr(OH2/PPy nanocomposites were tested in the photodegradation of MB dye under visible light irradiation. Also, the effects of MB dye initial concentration and the catalyst load on photodegradation efficiency were studied and discussed. Under the same conditions, the efficiency of photodegradation of MB employing the SrCO3-Sr(OH2/PPy nanocomposite increases as compared with that obtained employing the SrCO3-Sr(OH2 nanocomposite.

  8. High performance electrode material for supercapacitors based on α-Co(OH)2 nano-sheets prepared through pulse current cathodic electro-deposition (PC-CED)

    Science.gov (United States)

    Aghazadeh, Mustafa; Rashidi, Amir; Ganjali, Mohammad Reza

    2018-01-01

    In this paper, the well-defined nano-sheets of α-Co(OH)2 were prepared through the cathodic electrosynthesis from an additive-free aqueous cobalt nitrate bath. The pulse current cathodic electro-deposition (PC-CED) was used as the means for the controlling the OH- electrogeneration on the cathode surface. The characteristics and electrochemical behavior of the prepared cobalt hydroxide were also assessed through SEM, TEM, XRD, BET, and IR. The results proved the product to be composed of crystalline pure α phase of cobalt hydroxide with sheet-like morphology at nanoscale. Evaluations of the electrochemical behaviour of the α-Co(OH)2 nano-sheets revealed that they are capable to delivering the specific capacitance of 1122 F g-1 at a discharge load of 3 A g-1 and SC retention of 84% after 4000 continues discharging cycles, suggesting the nano-sheets as promising candidates for use in electrochemical supercapacitors. Further, the method used for the preparation of the compounds enjoys the capability of being scaled up. [Figure not available: see fulltext.

  9. VLA limits for comets Austin (1982 VI) and P/Crommelin (1983n) - evidence for a diffuse OH halo

    International Nuclear Information System (INIS)

    Schenewerk, M.S.; Palmer, P.; Snyder, L.E.; De Pater, I.; Chicago Univ., IL; Illinois Univ., Urbana; California Univ., Berkeley)

    1986-01-01

    Unsuccessful searches of Comet Austin (1982 VI = 1982g) and Comet P/Crommelin (1983n) for 18 cm wavelength OH emission or absorption and for continuum emission have been made with the VLA. The results of the OH searches of both comets and the 2 cm wavelength continuum search for Comet P/Crommelin are given here. The detection of OH emission and absorption in both comets with single-element telescopes and the nondetection of OH with the VLA are interpreted as evidence for a diffuse OH halo. The nondetection of continuum emission supports the growing body of observational evidence against the conventional icy-grain halo theory. 20 references

  10. A New Synthetic Compound, 2-OH, Enhances Interleukin-2 and Interferon-γ Gene Expression in Human Peripheral Blood Mononuclear Cells

    Directory of Open Access Journals (Sweden)

    Woan-Fang Tzeng

    2009-07-01

    Full Text Available A new synthetic compound, 6-hydroxy-2-tosylisoquinolin-1(2H-one (2-OH, was selected for immunopharmacological activity tests. The effects of 2-OH on human peripheral blood mononuclear cell (PBMC proliferation were determined by tritiated thymidine uptake. Compared to phytohemagglutinin (PHA; 5 μg/mL stimulation, 2-OH significantly enhanced PBMC proliferation in a dose-dependent manner. The 50% enhancement activity (EC50 for 2-OH was 4.4±0.1 μM. In addition, effects of 2-OH on interleukin-2 (IL-2 and interferon-γ (IFN-γ production in PBMC were determined by enzyme immunoassay. Results demonstrated that 2-OH stimulated IL-2 and IFN-γ production in PBMC. Data from reverse transcription-polymerase chain reaction (RT-PCR and real-time PCR indicated that IL-2 and IFN-γ mRNA expression in PBMC could be induced by 2-OH. Therefore, 2-OH enhanced IL-2 and IFN-γ production in PBMC by modulation their gene expression. We suggest that 2-OH may be an immunomodulatory agent.

  11. The far-infrared spectrum of the OH radical

    Science.gov (United States)

    Brown, J. M.; Schubert, J. E.; Evenson, K. M.; Radford, H. E.

    1982-01-01

    It is thought likely that the study of spectral lines in the far-infrared might provide at least as much information about the physics and chemistry of the interstellar environment as radioastronomy. However, by comparison with the microwave region, the far-infrared is largely unexplored. There is a pressing need for good laboratory data to aid searches and assignments of spectra from the interstellar clouds and nebulae. Brown et al. (1981) have conducted a study of the laser magnetic resonance (LMR) spectrum of the OH radical in its ground state at far-infrared wavelengths. The present investigation is concerned with the computation of the frequencies of individual hyperfine transitions involving all rotational levels up to J = 4 1/2. The results of the calculation are presented in a table. The results are summarized in a diagram which shows the low-lying energy levels of OH. The frequencies of transitions between levels studied directly in the LMR spectrum are quite reliable.

  12. A Novel Nanosecond Pulsed Power Unit for the Formation of ·OH in Water

    Science.gov (United States)

    Li, Shengli; Hu, Sheng; Zhang, Han

    2012-04-01

    A novel nanosecond pulsed power unit was developed for plasma treatment of wastewater, based on the theory of magnetic pulse compression and semiconductor opening switch (SOS). The peak value, rise time and pulse duration of the output voltage were observed to be -51 kV, 60 ns and 120 ns, respectively. The concentrations of ·OH generated by the novel nanosecond pulsed plasma power were determined using the method of high-performance liquid chromatography (HPLC). The results showed that the concentrations of ·OH increased with the increase in peak voltage, and the generation rates of ·OH were 4.1 × 10-10 mol/s, 5.7 × 10-10 mol/s, and 7.7 × 10-10 mol/s at 30 kV, 35 kV, and 40 kV, respectively. The efficiency of OH generation was found to be independent of the input parameters for applied power, with an average value of 3.23×10-12 mol/J obtained.

  13. A Novel Nanosecond Pulsed Power Unit for the Formation of ·OH in Water

    International Nuclear Information System (INIS)

    Li Shengli; Hu Sheng; Zhang Han

    2012-01-01

    A novel nanosecond pulsed power unit was developed for plasma treatment of wastewater, based on the theory of magnetic pulse compression and semiconductor opening switch (SOS). The peak value, rise time and pulse duration of the output voltage were observed to be -51 kV, 60 ns and 120 ns, respectively. The concentrations of ·OH generated by the novel nanosecond pulsed plasma power were determined using the method of high-performance liquid chromatography (HPLC). The results showed that the concentrations of ·OH increased with the increase in peak voltage, and the generation rates of ·OH were 4.1 × 10 -10 mol/s, 5.7 × 10 -10 mol/s, and 7.7 × 10 -10 mol/s at 30 kV, 35 kV, and 40 kV, respectively. The efficiency of OH generation was found to be independent of the input parameters for applied power, with an average value of 3.23×10 -12 mol/J obtained. (plasma technology)

  14. Characterization of vitamin D-deficient klotho(-/-) mice: do increased levels of serum 1,25(OH)2D3 cause disturbed calcium and phosphate homeostasis in klotho(-/-) mice?

    NARCIS (Netherlands)

    Woudenberg-Vrenken, T.E.; van der Eerden, B.C.; van der Kemp, A.W.; Leeuwen, J.P. van; Bindels, R.J.M.; Hoenderop, J.G.J.

    2012-01-01

    BACKGROUND: Klotho(-/-) mice display disturbed Ca(2+) and vitamin D homeostasis. Renal cytochrome p450 27b1 (Cyp27b1), the enzyme that catalyzes the hydrolysis to 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), is increased in klotho(-/-) mice, and a 1,25(OH)(2)D(3)-deficient diet partially normalized

  15. Synthesis and adsorption performance of Mg(OH){sub 2} hexagonal nanosheet–graphene oxide composites

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Mengdi; Xu, Jing; Cheng, Bei [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070 (China); Ho, Wingkei, E-mail: keithho@ied.edu.hk [Department of Science and Environmental Studies and Centre for Education in Environmental Sustainability, The Hong Kong Institute of Education, Tai Po, N.T. Hong Kong (China); Yu, Jiaguo, E-mail: jiaguoyu@yahoo.com [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070 (China); Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

    2015-03-30

    Graphical abstract: - Highlights: • Mg(OH){sub 2} hexagonal nanosheets with various mass of GO were prepared. • Mg(OH){sub 2}–GO composite showed enhanced adsorption capacity to congo red. • Zeta potential was used to explain preparation and adsorption mechanism. - Abstract: A series of Mg(OH){sub 2} hexagonal nanosheet–graphene oxide (GO) composites were synthesized through a simple hydrothermal method using magnesium nitrate and GO as precursors, sodium nitrate and sodium oxalate as additives, and sodium hydroxide and ammonia as precipitants. The as-prepared samples were characterized by X-ray diffraction, nitrogen adsorption–desorption isotherms, Raman spectroscopy, zeta potential analysis, and scanning electron microscopy (SEM). The adsorption affinity of the as-prepared samples toward congo red (CR) in water was analyzed and investigated. Results indicated that GO addition influenced the thickness, morphology, and adsorption performance of Mg(OH){sub 2} hexagonal nanosheets. As GO concentration increased, the thickness decreased. Especially at high GO concentration (1 wt%), Mg(OH){sub 2} hexagonal nanosheets changed into aggregated flower-like spheres. Addition of small amounts of GO also increased the adsorption capacity of Mg(OH){sub 2}. The equilibrium adsorption data of CR on the composite were further investigated by Langmuir and Freundlich models, indicating that the Langmuir model was much more suitable for the experimental data. The sample prepared with 0.5 wt% GO showed the highest adsorption capacity with 118 mg g{sup −1}. The experimental data were then fitted using pseudo-second order kinetics, suggesting that pseudo-second order kinetics could well describe the adsorption of CR on composites. Adsorption thermodynamics analysis showed that the adsorption activation energy was 29.2 kJ mol{sup −1}, suggesting that the adsorption of CR onto the samples was physical adsorption. Adsorption between the samples and CR was mainly due to the

  16. Measurement of OH density and air-helium mixture ratio in an atmospheric-pressure helium plasma jet

    International Nuclear Information System (INIS)

    Yonemori, Seiya; Ono, Ryo; Nakagawa, Yusuke; Oda, Tetsuji

    2012-01-01

    The absolute density of OH radicals in an atmospheric-pressure helium plasma jet is measured using laser-induced fluorescence (LIF). The plasma jet is generated in room air by applying a pulsed high voltage onto a quartz tube with helium gas flow. The time-averaged OH density is 0.10 ppm near the quartz tube nozzle, decreasing away from the nozzle. OH radicals are produced from water vapour in the helium flow, which is humidified by water adsorbed on the inner surface of the helium line and the quartz tube. When helium is artificially humidified using a water bubbler, the OH density increases with humidity and reaches 2.5 ppm when the water vapour content is 200 ppm. Two-dimensional distribution of air-helium mixture ratio in the plasma jet is also measured using the decay rate of the LIF signal waveform which is determined by the quenching rate of laser-excited OH radicals. (paper)

  17. Controlled synthesis of MnSn(OH)6/graphene nanocomposites and their electrochemical properties as capacitive materials

    International Nuclear Information System (INIS)

    Wang Gongkai; Sun Xiang; Lu Fengyuan; Yu Qingkai; Liu Changsheng; Lian Jie

    2012-01-01

    We report the synthesis of novel MnSn(OH) 6 /graphene nanocomposites produced by a co-precipitation method and their potential application for electrochemical energy storage. The hydroxide decorated graphene nanocomposites display better performance over pure MnSn(OH) 6 nanoparticles because the graphene sheets act as conductive bridges improving the ionic and electronic transport. The crystallinity of MnSn(OH) 6 nanoparticles deposited on the surface of graphene sheets also impacts the capacitive properties as electrodes. The maximum capacitance of 31.2 F/g (59.4 F/g based on the mass of MnSn(OH) 6 nanoparticles) was achieved for the sample with a low degree of crystallinity. No significant degradation of capacitance occurred after 500 cycles at a current density of 1.5 A/g in 1 M Na 2 SO 4 aqueous solution, indicating an excellent electrochemical stability. The results serve as an example demonstrating the potential of integrating highly conductive graphene networks into binary metal hydroxide in improving the performance of active electrode materials for electrochemical energy storage applications. - Graphical abstract: Graphite oxide (GO) can be synthesized by oxidizing graphite using Hummers method. Graphene was reduced from GO by thermal exfoliation. In this work, MnSn(OH) 6 /graphene nano-composites were synthesized by a simple co-precipitation method and their electrochemical performances have been explored. Highlights: ► Noval MnSn(OH) 6 /graphene nano-composites were synthesized. ► Microstructure can be tailored by changing the reaction temperature and time. ► Crystallinity of MnSn(OH) 6 nanoparticles impacts capacitive properties as electrode. ► Nano-composites display improved electrochemical performance over MnSn(OH) 6 alone. ► Results serve as an example demonstrating the potential for energy storage.

  18. Isolation, expression and characterization of a novel dual serine protease inhibitor, OH-TCI, from king cobra venom.

    Science.gov (United States)

    He, Ying-Ying; Liu, Shu-Bai; Lee, Wen-Hui; Qian, Jin-Qiao; Zhang, Yun

    2008-10-01

    Snake venom Kunitz/BPTI members are good tools for understanding of structure-functional relationship between serine proteases and their inhibitors. A novel dual Kunitz/BPTI serine proteinase inhibitor named OH-TCI (trypsin- and chymotrypsin-dual inhibitor from Ophiophagus hannah) was isolated from king cobra venom by three chromatographic steps of gel filtration, trypsin affinity and reverse phase HPLC. OH-TCI is composed of 58 amino acid residues with a molecular mass of 6339Da. Successful expression of OH-TCI was performed as the maltose-binding fusion protein in E. coli DH5alpha. Much different from Oh11-1, the purified native and recombinant OH-TCI both had strong inhibitory activities against trypsin and chymotrypsin although the sequence identity (74.1%) between them is very high. The inhibitor constants (K(i)) of recombinant OH-TCI were 3.91 x 10(-7) and 8.46 x10(-8)M for trypsin and chymotrypsin, respectively. To our knowledge, it was the first report of Kunitz/BPTI serine proteinase inhibitor from snake venom that had equivalent trypsin and chymotrypsin inhibitory activities.

  19. Reactivities of tetracycline and oxytetracycline with OH radicals

    International Nuclear Information System (INIS)

    Dziegielewski, J.O.; Glowacki, P.

    1982-01-01

    Decomposition yields of tetracycline sulphate and oxytetracycline sulphate were determined in argon saturated 0.1N H 2 SO 4 solutions. The decomposition yields of teracyclines decrease in the presence of the Cl - ions. The reaction rate constants of the OH radicals with tetracyclines were also determined. (author)

  20. Near-UV OH Prompt Emission in the Innermost Coma of 103P/Hartley 2

    Energy Technology Data Exchange (ETDEWEB)

    La Forgia, Fiorangela [Department of Physics and Astronomy, University of Padova, Vicolo dellOsservatorio 3, I-35122 Padova (Italy); Bodewits, Dennis; A’Hearn, Michael F.; Protopapa, Silvia; Kelley, Michael S. P.; Sunshine, Jessica; Feaga, Lori; Farnham, Tony, E-mail: fiorangela.laforgia@unipd.it [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States)

    2017-11-01

    The Deep Impact spacecraft flyby of comet 103P/Hartley 2 occurred on 2010 November 4, 1 week after perihelion with a closest approach (CA) distance of about 700 km. We used narrowband images obtained by the Medium Resolution Imager on board the spacecraft to study the gas and dust in the innermost coma. We derived an overall dust reddening of 15%/100 nm between 345 and 749 nm and identified a blue enhancement in the dust coma in the sunward direction within 5 km from the nucleus, which we interpret as a localized enrichment in water ice. OH column density maps show an anti-sunward enhancement throughout the encounter, except for the highest-resolution images, acquired at CA, where a radial jet becomes visible in the innermost coma, extending up to 12 km from the nucleus. The OH distribution in the inner coma is very different from that expected for a fragment species. Instead, it correlates well with the water vapor map derived by the HRI-IR instrument on board Deep Impact . Radial profiles of the OH column density and derived water production rates show an excess of OH emission during CA that cannot be explained with pure fluorescence. We attribute this excess to a prompt emission process where photodissociation of H{sub 2}O directly produces excited OH*( A {sup 2}Σ{sup +}) radicals. Our observations provide the first direct imaging of near-UV prompt emission of OH. We therefore suggest the use of a dedicated filter centered at 318.8 nm to directly trace the water in the coma of comets.

  1. Near-UV OH Prompt Emission in the Innermost Coma of 103P/Hartley 2

    International Nuclear Information System (INIS)

    La Forgia, Fiorangela; Bodewits, Dennis; A’Hearn, Michael F.; Protopapa, Silvia; Kelley, Michael S. P.; Sunshine, Jessica; Feaga, Lori; Farnham, Tony

    2017-01-01

    The Deep Impact spacecraft flyby of comet 103P/Hartley 2 occurred on 2010 November 4, 1 week after perihelion with a closest approach (CA) distance of about 700 km. We used narrowband images obtained by the Medium Resolution Imager on board the spacecraft to study the gas and dust in the innermost coma. We derived an overall dust reddening of 15%/100 nm between 345 and 749 nm and identified a blue enhancement in the dust coma in the sunward direction within 5 km from the nucleus, which we interpret as a localized enrichment in water ice. OH column density maps show an anti-sunward enhancement throughout the encounter, except for the highest-resolution images, acquired at CA, where a radial jet becomes visible in the innermost coma, extending up to 12 km from the nucleus. The OH distribution in the inner coma is very different from that expected for a fragment species. Instead, it correlates well with the water vapor map derived by the HRI-IR instrument on board Deep Impact . Radial profiles of the OH column density and derived water production rates show an excess of OH emission during CA that cannot be explained with pure fluorescence. We attribute this excess to a prompt emission process where photodissociation of H 2 O directly produces excited OH*( A 2 Σ + ) radicals. Our observations provide the first direct imaging of near-UV prompt emission of OH. We therefore suggest the use of a dedicated filter centered at 318.8 nm to directly trace the water in the coma of comets.

  2. Rate Coefficients for the OH + (CHO)2 (Glyoxal) Reaction Between 240 and 400 K

    Science.gov (United States)

    Feierabend, K. J.; Talukdar, R. K.; Zhu, L.; Ravishankara, A. R.; Burkholder, J. B.

    2006-12-01

    Glyoxal (CHO)2, the simplest dialdehyde, is an end product formed in the atmospheric oxidation of biogenic hydrocarbons, for example, isoprene. As such, glyoxal plays a role in regional air quality and ozone production in certain locations. Glyoxal is lost in the atmosphere via UV photolysis and reaction with OH. However, the currently available rate coefficient data for the OH + glyoxal reaction is limited to a single room- temperature measurement made using the relative rate method. A determination of the rate coefficient temperature dependence is therefore needed for a more complete interpretation of the atmospheric processing of glyoxal. This study reports the rate coefficient for the OH + (CHO)2 reaction measured under pseudo- first-order conditions in OH ([(CHO)2] > 1000 [OH]0). OH radicals were produced using 248 nm pulsed laser photolysis of H2O2 or HNO3 and detected by pulsed laser induced fluorescence. The concentration of glyoxal in the reactor was determined using three independent techniques; gas flow rates as well as in situ UV and IR absorption. The total pressure in the reactor was varied from 40 to 300 Torr (He), and the rate coefficient was found to be independent of pressure over the temperature range studied. The rate coefficient exhibits a negative temperature dependence between 240 and 400 K consistent with the dependence previously observed for many other aldehydes. Our room-temperature rate coefficient is smaller than the relative rate value that is currently recommended for use in atmospheric model calculations. Our measured rate coefficients are discussed with respect to those for other aldehydes. The atmospheric implications of our work will also be discussed.

  3. Bioapplication and activity of fullerenol C60(OH)24

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-29

    Dec 29, 2008 ... represent a class of sphere-shaped molecules made entirely of .... 4942 Afr. J. Biotechnol. fullerenes. ... C60 and fullerenols C60(OH)x apparently employ different ... Alzheimer's and Parkinson's diseases, type-C hepatitis.

  4. Shock tube measurements of the branching ratios of propene + OH -> products

    KAUST Repository

    Khaled, Fathi

    2014-07-25

    Absolute rate coefficients for the reaction of OH radical with propene (C3H6) and five deutrated isotopes, propene-1-d1 (CDHCHCH3), propene-1,1-d2 (CD2CHCH3), propene-2-d1 (CH2CDCH3), propene-3,3,3-d3 (CH2CHCD3), and propene-d6 (C3D6), were measured in a shock tube behind reflected shock conditions over the temperature range of 812 K – 1460 K and pressures near 1 atm. The reaction progress was followed by monitoring OH radical near 306.7 nm using UV laser absorption. The first experimental measurements for the branching ratio of the title reaction are reported and compared with theoretical calculations. The allylic H atom abstraction of propene by OH radicals was found to be the most dominant reaction pathway followed by propen-1-yl and propen-2-yl channels over the entire temperature range of this study which is in line with theoretical predictions. Arrhenius parameters for various site-specific rate coefficients are provided for kinetic modeling.

  5. Synthesis and Application of One-Dimensional La(OH3 Nanostructures: An Overview

    Directory of Open Access Journals (Sweden)

    Xiang Xiao

    2014-01-01

    Full Text Available One-dimensional (1D semiconductor nanomaterials are of particular importance owing to their unique properties and potential applications. This review attempts to provide a comprehensive introduction of 1D La(OH3 nanostructures including nanowires, nanoneedles, nanobelts, and nanorods. Firstly, various strategies developed to fabricate the 1D La(OH3 nanostructures are discussed, such as precipitation and composite-hydroxide-mediated, hydrothermal, and solvothermal methods, accompanying the description of the corresponding growth mechanisms. Then, the unique properties such as novel physical properties of 1D La(OH3 nanostructures resulting from their unique electronic structures and numerous transition modes involving the 4f shells of these ions are represented in detail. Also, the wide applications in photocatalyst, capacitors, and photoluminescence based on the unique properties are discussed. Finally, the paper ends with a summary and some perspectives on the challenges and new directions in this emerging area.

  6. Purine biosynthesis in L1210 leukemia cells is inhibited by 7-hydroxymethotrexate (7-OH-MTX) polyglutamates (PGS)

    International Nuclear Information System (INIS)

    Seither, R.L.; Matherly, L.H.; Goldman, I.D.

    1986-01-01

    The biochemical basis for 7-OH-MTX cytotoxicity was examined in L1210 tumor cells. Cells were exposed to 100 μM 7-OH-MTX (approx. 50% growth inhibition) or 10 μM methotrexate (MTX) (approx. 95% growth inhibition) for 6 hrs to allow high levels of PGS to accumulate. Dihydrofolate reductase (DHFR) activity was assessed by dihydrofolate (FH 2 ) pools labeled with 5-formyl-[ 3 H]-tetrahydrofolate (5μM) or 3 H-folic acid (1 μM). FH 2 was not elevated above control levels in 7-OH-MTX treated cells, in contrast to MTX treated cells in which FH 2 increased 4- to 7-fold. 3 H-Deoxyuridine incorporation into DNA was not inhibited in cells containing high levels (11.5 nmol/g dry wt.) of 7-OH-MTX tetraglutamate (7-OH-4-NH 2 -10-CH 3 -PteGlu 4 ), well in excess of the DHFR-binding capacity (7.3 +/- 0.9 nmol/g), indicating a normal rate of thymidylate synthesis. Although small amounts of 7-OH-MTX and its PGS were bound to DHFR in L1210 cells, as assessed by gel filtration, there was evidence for the preferential binding of 7-OH-MTX tetraglutamate. In all cases this was well below the DHFR binding capacity, consistent with normal rates of deoxyuridine metabolism and FH 2 levels in the cell. Incorporation of 14 C-formate (60 min) into thymidylate and amino acids was unaffected by 7-OH-MTX, yet incorporation into purines was inhibited over 50%, supporting a block(s) in de novo purine biosynthesis

  7. Electrochemical reduction approach-based 3D graphene/Ni(OH)2 electrode for high-performance supercapacitors

    International Nuclear Information System (INIS)

    Yan, Huijun; Bai, Jianwei; Wang, Bin; Yu, Lei; Zhao, Lin; Wang, Jun; Liu, Qi; Liu, Jingyuan; Li, Zhanshuang

    2015-01-01

    Highlights: • 3D graphene foam is synthesized by a simple electrochemical reduction method. • The 3D graphene/Ni(OH) 2 composite is used as a monolithic free-standing electrode material. • The 3D conductive graphene network improves the contact between electrode and electrolyte. • Compositing graphene with Ni(OH) 2 sheets take full advantage of the synergistic effects. • Results show that the as-synthesized products have good electrochemical property. - Abstract: Using a simple electrochemical reduction approach, we have produced three-dimensional (3D) graphene foam having high conductivity and well-defined macroporous structure. Through a hydrothermal process, Ni(OH) 2 sheets are grown in-situ onto the graphene surface. This monolithic 3D graphene/Ni(OH) 2 composite is used as the free-standing electrode for supercapacitor application; it shows a high specific capacitance of 183.1 F g −1 (based on the total mass of the electrode), along with excellent rate capability and cycle performance. The asymmetric supercapacitor based on the 3D graphene/Ni(OH) 2 as a positive electrode and active carbon (AC) as a negative electrode is also assembled and it exhibits a specific capacitance of 148.3 F g −1 at 0.56 A g −1 and a high energy density of 52.7 W h kg −1 at a power density of 444.4 W kg −1 . Moreover, 3D graphene/Ni(OH) 2 //AC has a good cycle stability (87.9% capacitance retention after 1000 cycles), making it promising as one of the most attractive candidates for electrochemical energy storage. This excellent electrochemical performance results from the multiplexed 3D graphene network facilitating electron transport; the interlaced Ni(OH) 2 sheets shorten ion diffusion paths and facilitate the rapid migration of electrolyte ions

  8. [Effects of hot-NaOH pretreatment on Jerusalem artichoke stalk composition and subsequent enzymatic hydrolysis].

    Science.gov (United States)

    Wang, Qing; Qiu, Jingwen; Li, Yang; Shen, Fei

    2015-10-01

    In order to explore the possibility of Jerusalem artichoke stalk for bioenergy conversion, we analyzed the main composition of whole stalk, pitch, and core of the stalk. Meanwhile, these parts were pretreated with different NaOH concentrations at 121 degrees C. Afterwards, enzymatic hydrolysis was performed to evaluate the pretreatment efficiency. Jerusalem artichoke stalk was characterized by relatively high lignin content (32.0%) compared with traditional crop stalks. The total carbohydrate content was close to that of crop stalks, but with higher cellulose content (40.5%) and lower hemicellulose (19.6%) than those of traditional crop stalks. After pretreatment, the lignin content in the whole stalk, pitch, and core decreased by 13.1%-13.4%, 8.3%-13.5%, and 19.9%-27.2%, respectively, compared with the unpretreated substrates. The hemicellulose content in the whole stalk, pitch, and core decreased 87.8%-96.9%, 87.6%-95.0%, and 74.0%-90.2%, respectively. Correspondingly, the cellulose content in the pretreated whole stalk, pitch, and core increased by 56.5%-60.2%, 52.2%-55.4%, and 62.7%-73.2%, respectively. Moreover, increase of NaOH concentration for pretreatment could improve the enzymatic hydrolysis of the whole stalk and pitch by 2.3-2.6 folds and 10.3-18.5 folds, respectively. The hydrolysis of pretreated stalk core decreased significantly as 2.0 mol/L NaOH was employed, although the increased NaOH concentration can also improve its hydrolysis performance. Based on these results, hot-NaOH can be regarded as an option for Jerusalem artichoke stalk pretreatment. Increasing NaOH concentration was beneficial to hemicellulose and lignin removal, and consequently improved sugar conversion. However, the potential decrease of sugar conversion of the pretreated core by higher NaOH concentration suggested further optimization on the pretreatment conditions should be performed.

  9. Assessing Many-Body Effects of Water Self-Ions. I: OH-(H2O) n Clusters.

    Science.gov (United States)

    Egan, Colin K; Paesani, Francesco

    2018-04-10

    The importance of many-body effects in the hydration of the hydroxide ion (OH - ) is investigated through a systematic analysis of the many-body expansion of the interaction energy carried out at the CCSD(T) level of theory, extrapolated to the complete basis set limit, for the low-lying isomers of OH - (H 2 O) n clusters, with n = 1-5. This is accomplished by partitioning individual fragments extracted from the whole clusters into "groups" that are classified by both the number of OH - and water molecules and the hydrogen bonding connectivity within each fragment. With the aid of the absolutely localized molecular orbital energy decomposition analysis (ALMO-EDA) method, this structure-based partitioning is found to largely correlate with the character of different many-body interactions, such as cooperative and anticooperative hydrogen bonding, within each fragment. This analysis emphasizes the importance of a many-body representation of inductive electrostatics and charge transfer in modeling OH - hydration. Furthermore, the rapid convergence of the many-body expansion of the interaction energy also suggests a rigorous path for the development of analytical potential energy functions capable of describing individual OH - -water many-body terms, with chemical accuracy. Finally, a comparison between the reference CCSD(T) many-body interaction terms with the corresponding values obtained with various exchange-correlation functionals demonstrates that range-separated, dispersion-corrected, hybrid functionals exhibit the highest accuracy, while GGA functionals, with or without dispersion corrections, are inadequate to describe OH - -water interactions.

  10. 77 FR 38490 - Safety Zone; Mentor Harbor Yachting Club Fireworks, Lake Erie, Mentor, OH

    Science.gov (United States)

    2012-06-28

    ...-AA00 Safety Zone; Mentor Harbor Yachting Club Fireworks, Lake Erie, Mentor, OH AGENCY: Coast Guard, DHS... Erie, Mentor, OH. This safety zone is intended to restrict vessels from a portion of Lake Erie during the Mentor Harbor Yachting Club fireworks display. This temporary safety zone is necessary to protect...

  11. Rate constant for the reaction of OH with CH3CCl2F (HCFC-141b) determined by relative rate measurements with CH4 and CH3CCl3

    Science.gov (United States)

    Huder, Karin; Demore, William B.

    1993-01-01

    Determination of accurate rate constants for OH abstraction is of great importance for the calculation of lifetimes for HCFCs and their impact on the atmosphere. For HCFC-141b there has been some disagreement in the literature for absolute measurements of this rate constant. In the present work rate constant ratios for HCFC-141b were measured at atmospheric pressure in the temperature range of 298-358 K, with CH4 and CH3CCl3 as reference gases. Ozone was photolyzed at 254 nm in the presence of water vapor to produce OH radicals. Relative depletions of 141b and the reference gases were measured by FTIR. Arrhenius expressions for 141b were derived from each reference gas and found to be in good agreement with each other. The combined expression for HCFC-141b which we recommend is 1.4 x 10 exp -12 exp(-1630/T) with k at 298 K being 5.9 x 10 exp -15 cu cm/molec-s. This value is in excellent agreement with the JPL 92-20 recommendation.

  12. Testing fast photochemical theory during TRACE-P based on measurements of OH, HO2, and CH2O

    Science.gov (United States)

    Olson, Jennifer R.; Crawford, J. H.; Chen, G.; Fried, A.; Evans, M. J.; Jordan, C. E.; Sandholm, S. T.; Davis, D. D.; Anderson, B. E.; Avery, M. A.; Barrick, J. D.; Blake, D. R.; Brune, W. H.; Eisele, F. L.; Flocke, F.; Harder, H.; Jacob, D. J.; Kondo, Y.; Lefer, B. L.; Martinez, M.; Mauldin, R. L.; Sachse, G. W.; Shetter, R. E.; Singh, H. B.; Talbot, R. W.; Tan, D.

    2004-08-01

    Measurements of several short-lived photochemical species (e.g., OH, HO2, and CH2O) were obtained from the DC-8 and P3-B aircraft during the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) campaign. To assess fast photochemical theory over the east Asian coast and western Pacific, these measurements are compared to predictions using a photochemical time-dependent box model constrained by coincident measurements of long-lived tracers and physical parameters. Both OH and HO2 are generally overpredicted by the model throughout the troposphere, which is a different result from previous field campaigns. The calculated-to-observed ratio of OH shows an altitude trend, with OH overpredicted by 80% in the upper troposphere and by 40-60% in the middle troposphere. Boundary layer and lower tropospheric OH ratios decrease from middle tropospheric values to 1.07 for the DC-8 and to 0.70 for the P3-B. HO2 measured on the DC-8 is overpredicted by a median of 23% and shows no trend in the agreement with altitude. Three subsets of data which compose 12% of the HO2 measurements represent outliers with respect to calculated-to-observed ratios: stratospherically influenced air, upper tropospheric data with NO > 135 pptv, and data from within clouds. Pronounced underpredictions of both HO2 and OH were found for stratospherically influenced air, which is in contrast to previous studies showing good agreement of predicted and observed HOx in the stratosphere. Observational evidence of heterogeneous uptake of HO2 within low and middle tropospheric clouds is presented, though there is no indication of significant HO2 uptake within higher-altitude clouds. Model predictions of CH2O are in good agreement with observations in the median for background concentrations, but a large scatter exists. Factors contributing to this scatter are examined, including the limited availability of some important constraining measurements, particularly CH3OOH. Some high concentrations of CH2O

  13. Developmental and Reproductive Effects of SE5-OH: An Equol-Rich Soy-Based Ingredient

    International Nuclear Information System (INIS)

    Matulka, R.A.; Burdock, G.; Matsuura, I.; Uesugi, T.; Ueno, T.

    2009-01-01

    Consumption of the isoflavones daidzein, genistein, glycitein, and their structural analogues is generally considered beneficial to human health. Equol is not found in soy, but is converted from daidzein by human gut bacterial flora. Research indicates that between 30-50% of the population is capable of converting daidzein to equol; therefore, there has been recent development of a new equol-rich functional food that relies on bacterial conversion of daidzein to equol under strictly controlled conditions. Therefore, a new equol-rich soy product (SE5-OH) has been developed, based on the bacterial conversion of daidzein; and its reproductive and developmental toxicity has been evaluated in a two-generation study and a developmental toxicity study with Sprague-Dawley rats at dose levels of 200, 1000, and 2000 mg/kg/day by gavage. SE5-OH contains approximately 0.65% equol, 0.024% daidzein, 0.022% genistein, and 0.30% glycitein. From the reproductive study, the no-observed-adverse-effect-level (NOAEL) for SE5-OH determined for both male and female rats is 1000 mg/kg/day (6.5 mg equol/kg/day). In the developmental toxicity phase of the study, no effects by SE5-OH were found in the embryo-fetus at any of the doses tested. The NOAEL for developmental effects of SE5-OH is 2000 mg/kg/day (13 mg equol/kg/day).

  14. Association between serum concentration of 25-hydroxyvitamin D [25(OH)D] and chronic periodontitis

    Science.gov (United States)

    Primasari, A.; Sihombing, K. P.

    2018-03-01

    Serum concentration of [25(OH)D] in Indonesia is at low level although Indonesia is one of Asia country which has a tropical climate. Vitamin D as an immunomodulatory agent invitro and in animal studies. However, data from clinical studies involvement vitamin D to chronic periodontitis are still controversy. The aim of this study was to evaluate the association between serum concentration of [25(OH)D] and chronic periodontitis. Totally 45 chronic periodontitis patients were analyzed. Spearman correlation models adjusted for subject and parameter included periodontal pocket depth (PPD), clinical attachment loss (CAL), and bleeding on probing (BOP) are analyzed. Totally 51.11% person have serum concentration of [25(OH)D] 21-50ng/mL were called insufficiency, and 15.56% is deficiency. Mean values of PPD >3mm indicating moderate criteria, CAL >4mm meaning severe criteria, and mean grade of BOP >2 degrees means the interdental papilla appears to be filled with little or much blood. Spearman correlation test results showed an inverse correlation between serum concentration of [25(OH)D] to the value of PPD, CAL, and BOP, however, was not statistically significant (r PPD -0.09; r CAL -0.118; r BOP 0.001, p>0.05). Insufficiency serum concentration of 25- hydroxyvitamin D [25(OH)D] was not associated significantly with PPD, CAL, and BOP of chronic periodontitis.

  15. Reactivities of tetracycline and oxytetracycline with OH radicals

    Energy Technology Data Exchange (ETDEWEB)

    Dziegielewski, J O; Glowacki, P [Uniwersytet Slaski, Katowice (Poland)

    1982-05-03

    Decomposition yields of tetracycline sulphate and oxytetracycline sulphate were determined in argon saturated 0.1N H/sub 2/SO/sub 4/ solutions. The decomposition yields of teracyclines decrease in the presence of the Cl/sup -/ ions. The reaction rate constants of the OH radicals with tetracyclines were also determined.

  16. Spin-glass state in the mixed system (Co1-xFex)2(OH)3Cl on deformed pyrochlore lattice

    International Nuclear Information System (INIS)

    Fujihala, M.; Hagihala, M.; Zheng, X.G.; Kawae, T.

    2009-01-01

    Magnetic interactions in a new geometrically frustrated system (Co 1-x Fe x ) 2 (OH) 3 Cl are investigated using magnetic susceptibility and μSR study. While Co 2 (OH) 3 Cl is ferromagnetic and Fe 2 (OH) 3 Cl antiferromagnetic, the partially substituted series (Co 1-x Fe x ) 2 (OH) 3 Cl show spin-glass behaviours, wherein ferromagnetic interactions prevail for low Fe concentration and antiferromagnetic ones prevail for high Fe concentration. In special, analysis of the AC magnetic susceptibility and ZF-μ + SR for the x=0.5 sample suggest that CoFe(OH) 3 Cl has both features of chemically disordered random spin glass and geometrically frustrated spin glass. It is also the first spin-glass system for the newly found geometric frustration series M 2 (OH) 3 X.

  17. Equatorial enhancement of the nighttime OH mesospheric infrared airglow

    International Nuclear Information System (INIS)

    Baker, D J; Thurgood, B K; Harrison, W K; Mlynczak, M G; Russell, J M

    2007-01-01

    Global measurements of the hydroxyl mesospheric airglow over an extended period of time have been made possible by the NASA SABER infrared sensor aboard the TIMED satellite which has been functioning since December of 2001. The orbital mission has continued over a significant portion of a solar cycle. Experimental data from SABER for several years have exhibited equatorial enhancements of the nighttime mesospheric OH (Δv=2) airglow layer consistent with the high average diurnal solar flux. The brightening of the OH airglow typically means more H+O 3 is being reacted. At both the spring and autumn seasonal equinoxes when the equatorial solar UV irradiance mean is greatest, the peak volume emission rate (VER) of the nighttime Meinel infrared airglow typically appears to be both significantly brighter plus lower in altitude by several kilometres at low latitudes compared with midlatitude findings

  18. 41 CFR 102-38.105 - Under what conditions may we negotiate sales of personal property?

    Science.gov (United States)

    2010-07-01

    ... property when— (a) The personal property has an estimated fair market value that does not exceed $15,000... may we negotiate sales of personal property? 102-38.105 Section 102-38.105 Public Contracts and... REGULATION PERSONAL PROPERTY 38-SALE OF PERSONAL PROPERTY Sales Process Negotiated Sales § 102-38.105 Under...

  19. Spectrum of OH-stretching vibrations of water in a "floating" water bridge

    Science.gov (United States)

    Oshurko, V. B.; Ropyanoi, A. A.; Fedorov, A. N.; Fedosov, M. V.; Shelaeva, N. A.

    2012-11-01

    The axial distribution (over the cross section) of the spectra of the OH-stretching band of water in a water bridge is investigated using the Raman scattering method. It is found that the axial structure of the bridge is inhomogeneous: the core at the center of the bridge contains a larger amount of water with an "icelike" structure and a presumably larger number of H+ ions, while the outer layer probably consists of water with a larger number of OH- ions.

  20. Crystal structure of vanuralite, Al[(UO{sub 2}){sub 2}(VO{sub 4}){sub 2}](OH) . 8.5H{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Plasil, Jakub [Czech Academy of Sciences, Praha (Czech Republic). Inst. of Physics

    2017-07-01

    Vanuralite, Al[(UO{sub 2}){sub 2}(VO{sub 4}){sub 2}](OH) . 8.5H{sub 2}O, is a rare supergene uranyl vanadate that forms during hydration-oxidation weathering of uraninite in oxide zones of U deposits. On the basis of single-crystal X-ray diffraction data it is monoclinic, space group P2{sub 1}/n, with a = 10.4637(10), b = 8.4700(5), c = 20.527(2) Aa, β = 102.821(9) , V=1773.9(3) Aa{sup 3} and Z = 4, D{sub calc.} = 3.561 g cm{sup -3}. The structure of vanuralite (R = 0.058 for 2638 unique observed reflections) contains uranyl vanadate sheets of francevillite topology of the composition [(UO{sub 2}){sub 2}(VO{sub 4}){sub 2}]{sup 2-}. Sheets are stacked perpendicular to c, and an interstitial complex {sup [6]}Al(OH)(H{sub 2}O){sub 4}(H{sub 2}O){sub 4.5}; adjacent structural sheets are linked through an extensive network of hydrogen bonds. Vanuralite is the most complex mineral among uranyl vanadates, with 961 bits/cell. The scarcity of occurrences is probably caused by the less common combination of elements present in the structure, as well as the relatively high complexity of the structure (compared to related minerals), arising namely from the complicated network of H-bonds.

  1. Self-Templated Synthesis of Porous Ni(OH)2 Nanocube and Its High Electrochemical Performance for Supercapacitor.

    Science.gov (United States)

    Li, Liang; Tan, Li; Li, Gengnan; Zhang, Yumeng; Liu, Lili

    2017-10-31

    Porous Ni(OH) 2 nanocubes were successfully fabricated by a simple self-sacrificial-template protocol using Ni-Co Prussian blue analogue (PBA) as precursor. When treated with NaOH, the simultaneous corrosion of Ni-Co PBA precursor and formation of amorphous Ni(OH) 2 resulted in porous Ni(OH) 2 nanocubes with uniform size of about 100 nm. Due to the large specific surface area and unique regular porous structure, the as-prepared materials showed large specific capacitance, relatively stable rate capability and long cycle stability when used as electrode materials for supercapacitors. With the voltage between 0.00 and 0.45 V versus Ag/AgCl, the specific capacitance can achieve 1842 F/g at a current density of 1 A/g.

  2. Formation pathways of DMSO(2) in the addition channel of the OH-initiated DMS oxidation: A theoretical study.

    Science.gov (United States)

    Ramírez-Anguita, Juan M; González-Lafont, Angels; Lluch, José M

    2009-07-15

    The production of dimethyl sulfoxide (DMSO) and dimethyl sulfone (DMSO(2)) in the dimethyl sulfide (DMS) degradation scheme initiated by the hydroxyl (OH) radical has been shown to be very sensitive to nitrogen oxides (NO(x)) levels. In the present work we have explored the potential energy surfaces corresponding to several reaction pathways which yield DMSO(2) from the CH(3)S(O)(OH)CH(3) adduct [including the formation of CH(3)S(O)(OH)CH(3) from the reaction of DMSO with OH] and the reaction channels that yield DMSO or/and DMSO(2) from the CH(3)S(O(2))(OH)CH(3) adduct are also studied. The formation of the CH(3)S(O(2))(OH)CH(3) adduct from CH(3)S(OH)CH(3) (DMS-OH) and O(2) was analyzed in our previous work. All these pathways due to the presence of NO(x) (NO and NO(2)) and also due to the reactions with O(2), OH and HO(2) are compared with the objective of inferring their kinetic relevance in the laboratory experiments that measure DMSO(2) (and DMSO) formation yields. In particular, our theoretical results clearly show the existence of NO(x)-dependent pathways leading to the formation of DMSO(2), which could explain some of these experimental results in comparison with experimental measurements carried out in NO(x)-free conditions. Our results indicate that the relative importance of the addition channel in the DMS oxidation process can be dependent on the NO(x) content of chamber experiments and of atmospheric conditions. (c) 2008 Wiley Periodicals, Inc.

  3. The borosulfates K{sub 4}[BS{sub 4}O{sub 15}(OH)], Ba[B{sub 2}S{sub 3}O{sub 13}], and Gd{sub 2}[B{sub 2}S{sub 6}O{sub 24}

    Energy Technology Data Exchange (ETDEWEB)

    Gross, Peter; Kirchhain, Arno; Hoeppe, Henning A. [Universitaet Augsburg, Institut fuer Physik (Germany)

    2016-03-18

    K{sub 4}[BS{sub 4}O{sub 15}(OH)], Ba[B{sub 2}S{sub 3}O{sub 13}], and Gd{sub 2}[B{sub 2}S{sub 6}O{sub 24}] were obtained by a new synthetic approach. The strategy involves initially synthesizing the complex acid H[B(HSO{sub 4}){sub 4}] which is subsequently reacted in an open system with anhydrous chlorides of K, Ba, and Gd to the respective borosulfates and a volatile molecule (HCl). Furthermore, protonated borosulfates should be accessible by appropriate stoichiometry of the starting materials, particularly in closed systems, which inhibit deprotonation of H[B(HSO{sub 4}){sub 4}] via condensation and dehydration. This approach led to the successful synthesis of the first divalent and trivalent metal borosulfates (Ba[B{sub 2}S{sub 3}O{sub 13}] with band-silicate topology and Gd{sub 2}[B{sub 2}S{sub 6}O{sub 24}] with cyclosilicate topology) and the first hydrogen borosulfate K{sub 4}[BS{sub 4}O{sub 15}(OH)]. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. In situ synthesis of 3D CoS nanoflake/Ni(OH)_2 nanosheet nanocomposite structure as a candidate supercapacitor electrode

    International Nuclear Information System (INIS)

    Li, Songzhan; Wen, Jian; Chen, Tian; Xiong, Liangbin; Wang, Jianbo; Fang, Guojia

    2016-01-01

    A three-dimensional (3D) CoS/Ni(OH)_2 nanocomposite structure based on CoS nanoflakes and two-dimensional (2D) Ni(OH)_2 nanosheets were in situ synthesized on Ni foam by a whole hydrothermal reaction and electrodeposition process. The 3D CoS/Ni(OH)_2 nanocomposite structures demonstrate the combined advantages of a sustained cycle stability of CoS and high specific capacitance from Ni(OH)_2. The obtained CoS/Ni(OH)_2 nanocomposite structures on Ni foam can directly serve as a binder-free electrode for a supercapacitor. For the 3D CoS/Ni(OH)_2 nanocomposite electrode, the high specific capacitance is 1837 F g"−"1 at a scan rate of 1 mV s"−"1, which is obviously higher than both the bare CoS electrode and Ni(OH)_2 electrode. The galvanostatic charge and discharge measurements illustrate that the 3D CoS/Ni(OH)_2 nanocomposite electrode possesses excellent cycle stability, and it keeps a 95.8% retention of the initial capacity after 5000 cycles. Electrochemical impedance spectroscopy measurements also confirm that the 3D CoS/Ni(OH)_2 nanocomposite electrode has better electrochemical characteristics. These remarkable performances can be attributed to the unique 3D nanoporous structure of CoS/Ni(OH)_2 which leads to a large accessible surface area and a high stability during long-term operation. In addition, 2D Ni(OH)_2 nanosheets in 3D nanocomposite structures can afford rapid mass transport and a strong synergistic effect of CoS and Ni(OH)_2 as individual compositions contribute to the high performance of the nanocomposite structure electrode. These results may promote the design and implementation of nanocomposite structures in advanced supercapacitors. (paper)

  5. Formation of Mg(OH)2 nanowhiskers on LTA zeolite surfaces using a sol–gel method

    KAUST Repository

    Liu, Junqiang; Bae, Tae-Hyun; Esekhile, Omoyemen; Nair, Sankar; Jones, Christopher W.; Koros, William J.

    2011-01-01

    A facile three step sol-gel-precipitation process is used to synthesize Mg(OH)2 nanowhiskers on micron-sized zeolite 5A particle surfaces at room temperature. The putative amorphous gelation product, Mg(OH) n(OR)2-n, forms first by a controlled

  6. VLA observations of a highly symmetric OH maser in a bipolar nebula

    International Nuclear Information System (INIS)

    Morris, M.; Bowers, P.F.; Turner, B.E.

    1982-01-01

    The Very Large Array was used to map 1667 MHz OH maser emission from the bipolar nebula OH 231.8+4.2 at 23 distinct velocities within the unusual, 100 km s -1 wide profile. The source is large (approx.10''equivalent3 x 10 17 cm) and well resolved, and displays ordered large-scale velocity gradients. At most velocities, the maser maps display an unmistakable symmetry about the bipolar axis defined by the optical and infrared reflection nebulae. Most of the data can be accounted for by an axisymmetric model in which the measuring OH is concentrated toward the system's equatorial plane and is expanding radially away from the central star. The observation of complete rings of maser emission at some velocities, however, shows that the maser is also present at high latitudes above the equatorial plane. A model which incorporates these features plus other known aspects of bipolar nebulae is presented and discussed

  7. 羟基多溴联苯醚(3'-OH-BDE-7)的大鼠体外肝代谢研究%IN VITRO METABOLISM STUDY OF 3'-OH-2,4-diBDE-7 IN RAT LIVER S9 FRACTION

    Institute of Scientific and Technical Information of China (English)

    赖永权; 陈学国; 蔡宗苇

    2011-01-01

    本文利用液相色谱-质谱联用技术,建立了羟基多溴联苯醚3'-OH-BDE-7在S.D.大鼠肝匀浆中的体外代谢研究方法.实验结果表明,3'-OH-BDE-7的主要代谢产物为2,4-二溴苯酚和二羟基多溴联苯醚(diOHPBDEs),并且其在温孵30min,时代谢转化率为90%.3'-OH-BDE-7的代谢研究为其它羟基多溴联苯醚的相应研究提供了信息,其代谢行为也对更好地理解PBDEs和OH-PBDEs的毒理和动力学具有一定意义.%Polybrominated diphenyl ethers (PBDEs) are an important class of brominated flame retardants that have been widely used in industrial and consumer products. PBDEs have become worldwide environmental pollutants because of the bioaccumulation, long-distance transportation and potential biological toxicities.Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) are a relatively new group of phenolic compounds that have attracted particular interest due to their endocrine disrupting potency. OH-PBDEs are similar to PBDEs in chemical structure, but were reported to show stronger biological effects. In this study, we investigated in vitro metabolic behaviors of selected 3'-OH-BDE-7 in rat liver S9 fraction. The obtained results indicated that 2,4-dibromophenol and diOH-PBDEs were the major metabolites of OH-PBDEs. It's worth noting that the hydroquinone like metabolites might pose a potential health risk to human and wild animals.

  8. Immobilization of alcohol dehydrogenase on ceramic silicon carbide membranes for enzymatic CH3 OH production

    DEFF Research Database (Denmark)

    Zeuner, Birgitte; Ma, Nicolaj; Berendt, Kasper

    2018-01-01

    BACKGROUND Alcohol dehydrogenase (ADH; EC 1.1.1.1) catalyzes oxidation of CH3OH to CHOH during NAD+ reduction to NADH. ADH can also accelerate the reverse reaction, which is studied as part of cascadic enzymatic conversion of CO2 to CH3OH. In the present study, immobilization of ADH onto macropor......BACKGROUND Alcohol dehydrogenase (ADH; EC 1.1.1.1) catalyzes oxidation of CH3OH to CHOH during NAD+ reduction to NADH. ADH can also accelerate the reverse reaction, which is studied as part of cascadic enzymatic conversion of CO2 to CH3OH. In the present study, immobilization of ADH onto......‐of‐concept for the use of NaOH‐treated SiC membranes for covalent enzyme immobilization and biocatalytic efficiency improvement of ADH during multiple reaction cycles. These data have implications for the development of robust extended enzymatic reactions....

  9. Synchronous exfoliation and assembly of graphene on 3D Ni(OH)2 for supercapacitors.

    Science.gov (United States)

    Ma, Liguo; Zheng, Maojun; Liu, Shaohua; Li, Qiang; You, Yuxiu; Wang, Faze; Ma, Li; Shen, Wenzhong

    2016-11-08

    Nowadays, new approaches to fabricate high-performance electrode materials are of vital importance in the renewable energy field. Here, we present a facile synthesis procedure of 3D Ni(OH) 2 /graphene hybrids for supercapacitors via synchronous electrochemical-assisted exfoliation and assembly of graphene on 3D Ni(OH) 2 networks. With the assistance of an electric field, the electrochemically exfoliated high-quality graphene can be readily, uniformly assembled on the surfaces of 3D Ni(OH) 2 . When serving as electrode materials for supercapacitors, the resulting 3D Ni(OH) 2 /graphene composites exhibited excellent specific capacitance (263 mF cm -2 at 2 mA cm -2 ), remarkable rate capability and super-long cycle life (retention of 94.1% even after 10 000 continuous charge-discharge cycles), which may be attributed to their highly porous, stable 3D architecture as well as uniform, firm anchoring of ultrathin graphene on their surfaces. Therefore, our approach provides a facile strategy for the large-scale synthesis of high-quality graphene based composites towards various applications.

  10. One-pot hydrothermal synthesis of reduced graphene oxide/Ni(OH)2 films on nickel foam for high performance supercapacitors

    International Nuclear Information System (INIS)

    Min, Shudi; Zhao, Chongjun; Chen, Guorong; Qian, Xiuzhen

    2014-01-01

    Reduced graphene oxide (RGO) on nickel hydroxide (Ni(OH) 2 ) film was synthesized via a green and facile hydrothermal approach. In this process, graphene oxide (GO) was reduced by nickel foam (NF) while the nickel metal was oxidized to Ni(OH) 2 film simultaneously, which resulted in RGO on Ni(OH) 2 structure. The RGO/Ni(OH) 2 composite film was characterized using by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and field-emission scanning electron microscope (FESEM). The electrochemical performances of the supercapacitor with the as-synthesized RGO/Ni(OH) 2 composite films as electrodes were evaluated using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), electrochemical impedance spectrometry (EIS) in 1 M KOH aqueous solution. Results indicated that the RGO/Ni(OH) 2 /NF composite electrodes exhibited superior capacitive performance with high capability (2500 mF cm −2 at a current density of 5 mA cm −2 , or 1667 F g −1 at 3.3 A g −1 ), compared with pure Ni(OH) 2 /NF (450 mF cm −2 at 5 mA cm −2 , 409 F g −1 at 3.3 A g −1 ) prepared under the identical conditions. Our study highlights the importance of anchoring RGO films on Ni(OH) 2 surface for maximizing the optimized utilization of electrochemically active Ni(OH) 2 and graphene for energy storage application in supercapacitors

  11. New nighttime retrievals of O(3P) and OH densities in the mesosphere/lower thermosphere using SABER/TIMED observations

    Science.gov (United States)

    Panka, P.; Kutepov, A. A.; Kalogerakis, K. S.; Janches, D.; Feofilov, A.; Rezac, L.; Marsh, D. R.; Yigit, E.

    2017-12-01

    We present first retrievals of O(3P) and OH densities in the mesosphere/lower thermosphere (MLT) using SABER/TIMED OH 2.0 and 1.6 μm limb emission observations. Recently, Kaufmann et al. [2014] reported that current SABER O(3P) densities are on average 30% higher compared to other observations. In this study we applied new detailed non-LTE model [Panka et al. 2017] of nighttime OH(v), which accounts for the new mechanism OH(v≥5)+O(3P)→O(1D)+OH(v-5) of energy transfer recently suggested by Sharma et al. [2015] and confirmed through laboratory studies by Kalogerakis et al. [2016]. Based on this model we developed a new self-consistent two channel retrieval approach for O(3P) and OH density. Using this approach, we retrieved O(3P) densities that are 10-40% lower than current SABER O(3P), as well as total OH density which is retrieved for the first time using SABER observations. We compare our retrieveals with the results of other observations and models. As it was recently shown by Panka et al. [2017], the new mechanism of OH quenching produces a significant pumping of CO2 4.3 µm emission. We discuss the effects these new O(3P) and OH retrievals have on the nighttime CO2 density retrievals from the SABER 4.3 µm channel.

  12. Experimental and theoretical studies of the reaction of the OH radical with alkyl sulfides: 3. Kinetics and mechanism of the OH initiated oxidation of dimethyl, dipropyl, and dibutyl sulfides: reactivity trends in the alkyl sulfides and development of a predictive expression for the reaction of OH with DMS.

    Science.gov (United States)

    Williams, M B; Campuzano-Jost, P; Hynes, A J; Pounds, A J

    2009-06-18

    A pulsed laser photolysis-pulsed laser-induced fluorescence technique has been employed to measure rate coefficients for the OH-initiated oxidation of dimethyl sulfide (DMS), its deuterated analog (DMS-d(6)), dipropyl sulfide (DPS), and dibutyl sulfide (DBS). Effective rate coefficients have been measured as a function of the partial pressure of O(2) over the temperature range of 240-295 K and at 200 and 600 Torr total pressure. We report the first observations of an O(2) enhancement in the effective rate coefficients for the reactions of OH with DPS and DBS. All observations are consistent with oxidation proceeding via a two-channel oxidation mechanism involving abstraction and addition channels. Structures and thermochemistry of the DPSOH and DBSOH adducts were calculated. Calculated bond strengths of adducts increase with alkyl substitution but are comparable to that of the DMSOH adduct and are consistent with experimental observations. Reactivity trends across the series of alkyl sulfide (C(2)-C(8)) reactions are analyzed. All reactions proceed via a two-channel mechanism involving either an H-atom abstraction or the formation of an OH adduct that can then react with O(2). Measurements presented in this work, in conjunction with previous measurements, have been used to develop a predictive expression for the OH-initiated oxidation of DMS. This expression is based on the elementary rate coefficients in the two-channel mechanism. The expression can calculate the effective rate coefficient for the reaction of OH with DMS over the range of 200-300 K, 0-760 Torr, and 0-100% partial pressure of O(2). This expression expands on previously published work but is applicable to DMS oxidation throughout the troposphere.

  13. Mechanism and kinetic properties for the OH-initiated atmospheric oxidation degradation of 9,10-Dichlorophenanthrene

    Energy Technology Data Exchange (ETDEWEB)

    Dang, Juan; Shi, Xiangli; Zhang, Qingzhu, E-mail: zqz@sdu.edu.cn; Hu, Jingtian; Wang, Wenxing

    2015-02-01

    Chlorinated polycyclic aromatic hydrocarbons (ClPAHs) have become a serious environmental concern due to their widespread occurrence and dioxin-like toxicities. In this work, the mechanism of the OH-initiated atmospheric oxidation degradation of 9,10-dichlorophenanthrene (9,10-Cl{sub 2}Phe) was investigated by using high-accuracy quantum chemistry calculations. The rate constants of the crucial elementary reactions were determined by the Rice–Ramsperger–Kassel–Marcus (RRKM) theory. The theoretical results were compared with the available experimental data. The main oxidation products are a group of ring-retaining and ring-opening compounds including chlorophenanthrols, 9,10-dichlorophenanthrene-3,4-dione, dialdehydes, chlorophenanthrenequinones, nitro-9,10-Cl{sub 2}Phe and epoxides et al. The overall rate constant of the OH addition reaction is 2.35 × 10{sup −12} cm{sup 3} molecule{sup −1} s{sup −1} at 298 K and 1 atm. The atmospheric lifetime of 9,10-Cl{sub 2}Phe determined by OH radicals is about 5.05 days. This study provides a comprehensive investigation of the OH-initiated oxidation degradation of 9,10-Cl{sub 2}Phe and should contribute to clarifying its atmospheric fate. - Highlights: • We studied a comprehensive mechanism of OH-initiated degradation of 9,10-Cl{sub 2}Phe. • The atmospheric lifetime of 9,10-Cl{sub 2}Phe determined by OH radical is about 5.05 d. • The rate constants of the crucial elementary steps were evaluated. • Water plays an important role in the formation of nitro-9,10-Cl{sub 2}Phe.

  14. OH Airglow and Equatorial Variations Observed by ISUAL Instrument on Board the FORMOSAT 2 Satellite

    Directory of Open Access Journals (Sweden)

    Jan-Bai Nee

    2010-01-01

    Full Text Available OH airglow observed by the ISUAL (Imager of Sprites and Upper Atmospheric Lightning instrument on board the FORMOSAT 2 satellite is reported in this paper. The satellite is sun-synchronous and it returns to the same orbit at the same local time daily. By using this property, we can study the upper atmosphere in detail. With a CCD camera, ISUAL has measured the emission layers of OH Meinel band at 630 nm for several two-week periods in 2004 and 2007 in equatorial regions. ISUAL images are snapshots of the atmosphere 250 km (height ¡_ 1200 km (horizontal distance. These images of OH airglow are analyzed to derive its peak height and latitudinal variations. ISUAL observation is unique in its capability of continuous observation of the upper atmosphere as the satellite travels from south to north along a specific orbit. However, 630 nm filter also measured O(1D at 200 km, and there are interferences between O(1D and OH airglows as as observed from a distance in space. We have studied the overlap of two airglows by simulations, and our final analyses show that OH airglow can be correctly derived with its average peak height of 89 ¡_ 2.1 km usually lying within ¡_10¢X latitude about the equator. ISUAL data reveal detailed structures of equatorial OH airglow such as the existences of a few secondary maxima within the equatorial regions, and the oscillations of the peak latitudes. These results are discussed and compared with previous reports.

  15. Study on the Electrochemical Property of Microporous Cobalt Phosphite[Co_11(HPO_3)_8(OH)_6

    International Nuclear Information System (INIS)

    Lee, Dong Heon; Kang, Myunggoo; Jung, Hyun; Paek, Seung-Min

    2016-01-01

    Crystalline microporous cobalt phosphite, Co_11(HPO_3)_8(OH)_6, was prepared via facile hydrothermal route without the use of any templates or surfactants. The cobalt chloride hexahydrate (CoCl_2·6H_2O) and sodium hypophosphite monohydrate (NaH_2PO_2·H_2O) were employed as reactants, and sodium bicarbonate(NaHCO_3) was added to adjust the pH. The resultant Co_11(HPO_3)_8(OH)_6 shows dumbbell-like shape witha size of several micrometers. The obtained materials were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TGA), field-emission scanning electron microscopy (FE-SEM), and energy dispersive spectrometry (EDS). The Co_11(HPO_3)_8(OH)_6 is applied as electrochemical energy storage electrode material because of its unique microporous nature. Different aqueous electrolytes (LiOH, NaOH, and KOH) have been tested in order to study the effect of electrolyte cations on electrochemical behavior. To investigate the capacity and stability of Co_11(HPO_3)_8(OH)_6 electrode, cyclic voltammetry (CV), galvanostatic charge-discharge (GC), and cycle stability were performed in aqueous electrolytes with different cations at room temperature. We found that the electrochemical behavior of these materials is strongly dependent on the species of electrolyte cations (Li"+,Na"+, and K"+).

  16. Side-by-Side In(OH3 and In2O3 Nanotubes: Synthesis and Optical Properties

    Directory of Open Access Journals (Sweden)

    Tao Xiaojun

    2009-01-01

    Full Text Available Abstract A simple and mild wet-chemical approach was developed for the synthesis of one-dimensional (1D In(OH3 nanostructures. By calcining the 1D In(OH3 nanocrystals in air at 250 °C, 1D In2O3 nanocrystals with the same morphology were obtained. TEM results show that both 1D In(OH3 and 1D In2O3 are composed of uniform nanotube bundles. SAED and XRD patterns indicate that 1D In(OH3 and 1D In2O3 nanostructures are single crystalline and possess the same bcc crystalline structure as the bulk In(OH3 and In2O3, respectively. TGA/DTA analyses of the precursor In(OH3 and the final product In2O3 confirm the existence of CTAB molecules, and its content is about 6%. The optical absorption band edge of 1D In2O3 exhibits an evident blueshift with respect to that of the commercial In2O3 powders, which is caused by the increasing energy gap resulted from decreasing the grain size. A relatively strong and broad purple-blue emission band centered at 440 nm was observed in the room temperature PL spectrum of 1D In2O3 nanotube bundles, which was mainly attributed to the existence of the oxygen vacancies.

  17. Metal–organic frameworks assembled from lanthanide and 2,5-pyridinedicaboxylate with cubane-like [Ln{sub 4}(OH){sub 4}] building units

    Energy Technology Data Exchange (ETDEWEB)

    Abdelbaky, Mohammed S.M. [Departamentos de Química Física y Analítica y Química Orgánica e Inorgánica, University of Oviedo—CINN, Oviedo 33006 (Spain); Amghouz, Zakariae, E-mail: amghouz.uo@uniovi.es [Departamentos de Química Física y Analítica y Química Orgánica e Inorgánica, University of Oviedo—CINN, Oviedo 33006 (Spain); Servicios Científico-Técnicos, University of Oviedo—CINN, Oviedo 33006 (Spain); Fernández-Zapico, Eva; García-Granda, Santiago; García, José R. [Departamentos de Química Física y Analítica y Química Orgánica e Ino