Sample records for 4sosub 4center dot2hsub


    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. CENTER COURTYARD, FROM WEST SIDE OF SOUTHEAST PORTION OF BUILDING, LOOKING WEST. - Oakland Naval Supply Center, Administration Building-Dental Annex-Dispensary, Between E & F Streets, East of Third Street, Oakland, Alameda County, CA


    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OVERVIEW, HANGAR No. 3 (FOREGROUND), HANGAR No. 4 (CENTER), AND HANGAR No. 5 (BACKGROUND), FROM AIRCRAFT PARKING APRON, VIEW FACING NORTH - U.S. Marine Corps Base Hawaii, Kaneohe Bay, Hangar No. 4, First Street between A & B Streets, Kailua, Honolulu County, HI

  3. Symmetry-breaking Ta4+ centers in KTaO3

    NASA Astrophysics Data System (ADS)

    Laguta, V. V.; Zaritskii, M. I.; Glinchuk, M. D.; Bykov, I. P.; Rosa, J.; Jastrabík, L.


    A study of photoinduced Ta4+ centers in nominally pure KTaO3 single crystals has been carried out by electron-spin resonance. Two of these centers (Ta4+-VO and Ta4+-VO-Me4+) are connected with vacancies of oxygen (VO); a third center is associated with an OH- molecular ion (Ta4+-OH-). This assignment is made on the basis of concentration measurements of the corresponding centers after annealing in argon, oxygen, hydrogen, and H2O vapor atmospheres. It has been shown that the Ta4+ centers are shallow donors; at T>=30 K they are ionized and transformed into ordinary VO and OH- which are assumed to be the main lattice defects before illumination. Their energy levels are determined by the temperature dependence of the relaxation rate of the light-induced nonequilibrium localized electron population. The energy levels of Ta4+-VO and Ta4+-VO-Me4+ centers are situated at 26 and 8 meV below the bottom of the conduction band, respectively. The symmetry of the centers is inverse broken in the sense that the photoelectron is localized near one of two equivalent Ta5+ ions next to an oxygen vacancy or OH-. The role of VO defects and OH- molecules in the nucleation of local polar clusters in nominally pure KTaO3 crystals at low temperatures is discussed.

  4. Formation and annihilation of E4 centers in ZnO: Influence of hydrogen

    NASA Astrophysics Data System (ADS)

    Hupfer, A.; Bhoodoo, C.; Vines, L.; Svensson, B. G.


    Hydrothermally grown n-type ZnO bulk samples have been implanted with protons and deuterium ions to fluences in the range of 8 × 1010 to 8 × 1011 cm-2. The implantations were performed at the temperature of 285 K, and the samples were then analyzed in-situ by deep level transient spectroscopy (DLTS) using a setup connected to the implanter beam line. The concentration of the so-called E4 center, having an apparent energy level at ˜0.57 eV below the conduction edge, is found to increase linearly with the ion fluence and the generation rate is proportional to the elastic energy deposition, as expected for a primary defect. Isothermal annealing of the E4 center at temperatures between 290 and 315 K reveals first-order kinetics with the activation energy of ˜0.6 eV. The annealing rate is strongly enhanced with increasing hydrogen fluence, and a model invoking migration of interstitial hydrogen and subsequent reaction with E4 exhibits close agreement with the experimental data. The rate of electron capture by E4 during the DLTS filling pulse depends on temperature, and it displays a thermal barrier of ˜0.15 eV. Most of these experimental results for E4 conform to the theoretically predicted properties of the oxygen vacancy (VO) and a tentative assignment of E4 to VO is made, corroborating previous suggestions in the literature. In particular, the 0.57 eV level is ascribed to the double donor state of VO.

  5. Topotactic lithium exchange in the precursor catalyst VOHPO[sub 4][center dot]0. 5H[sub 2]O: The crystal structure of LiVOPO[sub 4][center dot]0. 5 H[sub 2]O

    SciTech Connect

    Lozano-Calero, D.; Bruque, S.; Aranda, M.A.G.; Martinez-Lara, M.; Moreno, L. )


    The synthesis and properties of a new lithium vanadyl(IV) phosphate, LiVOPO[sub 4][center dot]0.5H[sub 2]O, are reported. The synthesis was carried out by a lithium exchange reaction in VO(HPO[sub 4])[center dot]0.5H[sub 2]O with LiOH at low temperature in a nonaqueous medium. The crystal structure of LiVOPO[sub 4][center dot]0.5H[sub 2]O (space group P[sub 2[sub 1]2[sub 1]2], a = 7.4651(6) [Angstrom], b = 9.4167(8) [Angstrom], c = 6.0762(6) [Angstrom], Z = 4) was refined by the Rietveld method from laboratory X-ray powder diffraction data, giving R[sub wp] = 8.0% and R[sub F] = 6.5%. The structure is made up of layers made of VO[sub 6] dimers which are linked by phosphate groups. The framework of the starting material is maintained but the vanadium coordination sphere is more distorted and the lithium position is deduced from a difference Fourier map. The structural, thermal, and spectroscopic features are compared to those of the closely related H-derivative. 27 refs., 8 figs., 3 tabs.

  6. EPR and ab initio calculation study on the EI4 center in 4H- and 6H-SiC

    SciTech Connect

    Carlsson, P.; Son, N. T.; Janzen, E.; Gali, A.; Isoya, J.; Morishita, N.; Ohshima, T.; Magnusson, B.


    We present results from electron paramagnetic resonance (EPR) studies of the EI4 EPR center in 4H- and 6H-SiC. The EPR signal of the EI4 center was found to be drastically enhanced in electron-irradiated high-purity semi-insulating materials after annealing at 700-750 deg. C. Strong EPR signals of the EI4 center with minimal interferences from other radiation-induced defects in irradiated high-purity semi-insulating materials allowed our more detailed study of the hyperfine (hf) structures. An additional large-splitting {sup 29}Si hf structure and {sup 13}C hf lines of the EI4 defect were observed. Comparing the data on the hf interactions and the annealing behavior obtained from EPR experiments and from ab initio supercell calculations of different carbon-vacancy-related complexes, we suggest a complex between a carbon vacancy-carbon antisite and a carbon vacancy at the third-neighbor site of the antisite in the neutral charge state, (V{sub C}-C{sub Si}V{sub C}){sup 0}, as a new defect model for the EI4 center.

  7. Neutron and X-ray structural characterization of the hexaaquavanadium(II) compound VSO{sub 4}{center_dot}7H{sub 2}O

    SciTech Connect

    Cotton, F.A.; Falvello, L.R.; Pascual, I.; Tomas, M.; Murillo, C.A. |; Schultz, A.J.


    The title compound, for which crystals are more reactive toward oxygen than the chemically similar compound VSO{sub 4}{center_dot}6H{sub 2}O, has been prepared as large single crystals and characterized by both X-ray diffraction at room temperature and neutron diffraction at 11-16 K. VSO{sub 4}{center_dot}7H{sub 2}O crystallizes in the monoclinic space group P2{sub 1}/c, Z = 4, with the following cell dimensions, where in each case the room temperature X-ray value is given first followed by the 11-16 K neutron value: a = 14.130(3), 14.013(2) {angstrom}; b = 6.501(1), 6.481(1) {angstrom}; c = 11.017(2), 10.981(2) {angstrom}; {beta} = 105.64(2), 105.39(1){degrees}; V = 974.5(3), 961.5(3) {angstrom}{sup 3}. The structure was refined to residuals of R = 0.0289 and 0.0766 and quality of fit = 1.047 and 1.427 for X-ray and neutron data, respectively. It consists of two independent centrosymmetric V(H{sub 2}O){sub 6}{sup 2+} ions connected to a sulfate ion and an interstitial water molecule by an extensive network of hydrogen bonds. The room temperature and low-temperature structures are qualitatively identical. Each hydrogen atom is involved in a hydrogen bond. The network of hydrogen bonds is implicated in the stability of VSO{sub 4}{center_dot}7H{sub 2}O in the solid state in dry surroundings.

  8. Intercalation of aliphatic amines into the layered structure of vanadyl(IV) hydrogen phosphate hemihydrate (VOHPO[sub 4][center dot]0. 5H[sub 2]O)

    SciTech Connect

    Guliants, V.V.; Benziger, J.B.; Sundaresan, S. )


    The vanadyl(IV) hydrogen phosphate hemihydrate, VOHPO[sub 4][center dot]0.5H[sub 2]O, is a pyrolytic precursor of the vanadyl(IV) pyrophosphate phase, (VO)[sub 2]P[sub 2]O[sub 7], generally believed to be the active phase in the selective oxidation of n-butane into maleic anhydride. Pyrolytic transformation into the pyrophosphate phase occurs with conservation of a morphology of the material. VOHPO[sub 4][center dot]0.5H[sub 2]O is a layered hydrogen phosphate, where -POH groups form interlayer hydrogen bonds with the water molecules shared by two face-linked vanadyl octahedra. The structure of the hemihydrate is similar to that of [alpha]-zirconium hydrogen phosphate ([alpha]-ZrP), where hydrogen bonds are within the same layer and -POH groups are also pointed into the interlayer space. In contrast to [alpha]-ZrP, where extensive data exist, intercalation chemistry of the layered vanadyl(IV) hydrogen phosphate hemihydrate at present is a terra incognita. This paper reports the results of the first systematic study of VOHPO[sub 4][center dot]0.5H[sub 2]O intercalation with aliphatic amines as a new route to novel vanadyl(IV) phosphate phases. N-Alkylamines have been commonly known as excellent intercalation agents for testing the intracrystalline reactivity of layered oxides. Intercalated alkylamines may also facilitate introduction of thermostable guest molecules, or [open quotes]pillars[close quotes], by ion exchange producing microporous materials which can modify catalytic and sorptive properties. 9 refs., 6 figs., 2 tabs.

  9. Investigation of the Local Geometry and EPR Parameters of V3+ and Cr4+ Centers in Al2O3 Crystals

    NASA Astrophysics Data System (ADS)

    Feng, Wen-Lin; Wu, Xiao-Xuan; Wang, Fang; Zheng, Wen-Chen


    The EPR parameters (zero-field splitting D and g factors g||, g⊥) of 3d2 V3+ and Cr4+ centers in Al2O3 crystals are calculated by using the diagonalization of the complete energy matrix for 3d2 ions in trigonal symmetry. The crystalfield parameters are estimated for the superposition model related to the local geometry (or structure) of the impurity centers. From the calculations, the EPR parameters for both impurity centers are explained and the local structures (characterized by the impurity displacement Δz along the C3 axis and the displacement Δx of O2- ions in the oxygen triangle between the impurity and the vacant oxygen octahedron along the x-axis, resulting from the electrostatic repulsive force and the electronic cloud overlap) of these impurity centers are estimated. The results are discussed.

  10. Thermal properties and radiation damage in NaNH[sub 4]XO[sub 4][center dot]2H[sub 2]O single crystals (XO[sub 4] = SO[sub 4], SeO[sub 4])

    SciTech Connect

    Hilczer, B.; Szczepanska, L. ); Piskunowicz, P. ); Darwish, H.G. )


    Differential thermal analysis (DTA) studies of NaNH[sub 4]SO[sub 4][center dot]2H[sub 2]O, NaND[sub 4]SO[sub 4][center dot]2H[sub 2]O, and NANH[sub 4]SeO[sub 4][center dot]2H[sub 2]O single crystals were performed in the temperature range of the ferroelectric-paraelectric phase transition and of the dehydration process. The first-order phase transition at the Curie point was confirmed for NaNH[sub 4]SO[sub 4][center dot]2H[sub 2]O, whereas the transition in the isomorphous NaNH[sub 4]SeO[sub 4][center dot]2H[sub 2]O at the Curie temperature was found to be similar to a continuous (second order) with considerable higher transition enthalpy. Dehydration process of the crystals studied was found to proceed in two stages, with maximum dehydration rates at [approximately]355 and [approximately]400 K. A linear decrease in thermal energy related to the long-range ordering in NaNH[sub 4]SO[sub 4][center dot]2H[sub 2]O crystals was observed with the dose of [gamma]-cobalt-60 irradiation and discussed with respect to the radiation induced decrease in spontaneous polarization. 17 refs., 5 figs., 2 tabs.

  11. Copper uranyl phosphate and arsenate incorporating an organic ligand with a pillared layer structure: [Cu(4,4 Prime -bpy)(UO{sub 2}){sub 0.5}(HPO{sub 4})(H{sub 2}PO{sub 4})]{center_dot}H{sub 2}O and [Cu(4,4 Prime -bpy)(UO{sub 2}){sub 0.5}(HAsO{sub 4})(H{sub 2}AsO{sub 4})]{center_dot}1.5H{sub 2}O

    SciTech Connect

    Wang, Chih-Min; Lii, Kwang-Hwa


    Two mixed-metal uranium compounds, [Cu(4,4 Prime -bpy)(UO{sub 2}){sub 0.5}(HPO{sub 4})(H{sub 2}PO{sub 4})]{center_dot}H{sub 2}O (1) and [Cu(4,4 Prime -bpy)(UO{sub 2}){sub 0.5}(HAsO{sub 4})(H{sub 2}AsO{sub 4})]{center_dot}1.5H{sub 2}O (2) have been synthesized under hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction, fluorescence spectroscopy, and magnetic susceptibility. They are the first examples of mixed-metal uranium phosphate and arsenate incorporating an organic ligand. Their structures contain copper uranyl phosphate/arsenate layers which are covalently linked by 4,4 Prime -bpy pillars to form a 3-D framework structure. The fluorescence spectrum of 1 shows the characteristic vibronic structure of the UO{sub 2}{sup 2+} moiety despite the presence of copper(II) ions in its structure. The two compounds are isostructural and crystallize in the monoclinic space group C2/c with a=20.184(4) A, b=8.921(2) A, c=19.095(3) A, {beta}=115.15(1) Degree-Sign , and R{sub 1}=0.0244 for 1, and a=20.184(1) A, b=9.0210(5) A, c=19.714(1) A, {beta}=114.879(1) Degree-Sign , and R{sub 1}=0.0399 for 2. - Graphical abstract.: A new copper uranyl phosphate and the arsenate analog have been presented. The compounds contain copper uranyl phosphate/arsenate layers covalently linked by 4,4 Prime -bipyridine pillars into an open-framework structure.

  12. Photoluminescence of a Te4+ center in zinc borate glass.


    Masai, Hirokazu; Yamada, Yasuhiro; Okumura, Shun; Kanemitsu, Yoshihiko; Yoko, Toshinobu


    Photoluminescent (PL) properties related to Te(4+) species in zinc borate glasses are examined. Broad emission was observed by the excitation of the PL excitation peak of Te(4+) present at the optical absorption edge. The emission intensity of Te(4+) in 5TeO(2)-50ZnO-45B(2)O(3) glass was thermally quenched in a temperature region over 100 K, suggesting that concentration quenching preferentially occurred. The lifetime of the emission was approximately 2.5 μs, which is characteristic of relaxation from the triplet excitation state of an ns(2)-type center. PMID:24081051

  13. Synthesis and crystal structure of 3-ammoniumphenyl sulfone selenate, 3-aminophenyl sulfone [C{sub 12}H{sub 14}N{sub 2}O{sub 2}S]SeO{sub 4} {center_dot} [C{sub 12}H{sub 12}N{sub 2}O{sub 2}S

    SciTech Connect

    Mahroug, A.; Belhouchet, M. Mhiri, T.


    The crystal structure of [C{sub 12}H{sub 14}N{sub 2}O{sub 2}S]SeO{sub 4} {center_dot} [C{sub 12}H{sub 12}N{sub 2}O{sub 2}S] was determined by X-ray diffraction on single crystal. Crystals are orthorhombic, space group Pbca, with cell parameters a = 11.545 (1), b = 8.143 (1), c = 55.783(1)A, V = 5244.2 (8)A{sup 3} and Z = 8. The structure can be described as organic layers built by [C{sub 12}H{sub 14}N{sub 2}O{sub 2}S]{sup 2+} cations and [C{sub 12}H{sub 12}N{sub 2}O{sub 2}S] molecules, parallel to ab plane, between which the inorganic groups SeO{sub 4}{sup 2-} are inserted. In this atomic arrangement, H-bonds between the different species play an important role in the three-dimensional network cohesion.

  14. Temperature sensitivity (Q10), and dynamics of soil organic matter (SOM) decomposition in permafrost soils with different carbon quality and under experimental warming. R. Bracho1, E.A.G Schuur1, E. Pegoraro1, K.G. Crummer1, S. Natali2, J. Zhou, Y Luo3, J. L. Wu3, M. Tiedje4, K. Konstantinidis5 1Department of Biology, University of Florida, Gainesville, FL. 2Woods Hole Research Center, Falmouth, MA. 3Institute for Environmental Genomics and Department of Botany and Microbiology, University of Oklahoma, Norman, OK, 4Center for Microbial Ecology, Michigan State University, East Lansing, MI; 5Center for Bioinformatics and Computational Genomics and School of Biology, Georgia Institute of Technology, Atlanta, GA

    NASA Astrophysics Data System (ADS)

    Bracho, R. G.; Schuur, E. A.; Pegoraro, E.; Crummer, K. G.; Natali, S.; Zhou, J.; Wu, L.; Luo, Y.; Tiedje, J. M.; Konstantinidis, K.


    Permafrost soils contain approximately1700 Pg of carbon (C), twice the amount of C in the atmosphere. Temperatures in higher latitudes are increasing, inducing permafrost thaw and subsequent microbial decomposition of previously frozen C. This process is one of the most likely positive feedbacks to climate change. Understanding the temperature sensitivity (Q10) and dynamics of SOM decomposition under warming is essential to predict the future state of the earth - climate system. Alaskan tundra soils were exposed to two winter warming (WW) seasons in the field, which warmed the soils by 4°C to 40 cm depth. Soils were obtained from three depths (0 - 15, 15 - 25 and 45 - 55 cm) and differed in initial amounts of labile and recalcitrant C. Soils were incubated in the lab under aerobic conditions, at 15 and 25°C over 365 days. Q10 was estimated at 14, 100 & 280 days of incubation (DOI); C fluxes were measured periodically and dynamics of SOM decomposition (C pool sizes and decay rates) were estimated by fitting a two pool C model to cumulative respired C (Ccum, mgC/ginitialC). After two WW seasons, initial C content tended to decrease through the soil profile and C:N ratio was significantly decreased in the top 15 cm. After one year of incubation, Ccum was twice as high at 25°C as at 15°C and significantly decreased with depth. No significant WW field treatment was detected, although Ccum tended to be lower in warmed soils. Labile C accounted for up to 5% of initial soil C content in the top 15 cm and decreased with depth. Soils exposed to WW had smaller labile C pools, and higher labile C decay rates in the top 25 cm. Q10 significantly decreased with time and depth as labile pool decreased, especially for WW. This decrease with time indicates a lower temperature sensitivity of the most recalcitrant C pool. The deepest WW soil layer, where warming was more pronounced, had significantly lower Q10 compared to control soils at the same depth. After two seasons, the warming treatment affected decomposition by reducing labile C pools and increasing its decay rates. Warming also reduced temperature sensitivity, showing acclimation of the most recalcitrant C pool in the tundra ecosystem.

  15. Muscular Dystrophy


    ... in Duchenne muscular dystrophy. Dev. Med. Child Neurol. Mar 1995;37(3):260-269. 4. Centers for ... DM1) . The International Myotonic Dystrophy Consortium (IDMC). Neurology. Mar 28 2000;54(6):1218-1221. 5. Harper ...

  16. 26. In context, from northwest facing southeast, typical courtyard between ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    26. In context, from northwest facing southeast, typical courtyard between buildings, west side of Building I-4, center. - Clark Howell Homes (Public Housing), Bounded by North Avenue, Lovejoy Street, Mills Street & Luckie Street, Atlanta, Fulton County, GA

  17. Off-Season Enrollment Building.

    ERIC Educational Resources Information Center

    Wassom, Julie


    Maintains that the winter months are an ideal time to review and refine a child care center's marketing program. Highlights the following target areas for review: (1) marketing plan; (2) action plan; (3) center or company identity package; (4) center brochure; (5) photos; (6) web site; (7) advertisements; (8) publicity; (9) voice mail message;…

  18. Photocopy of photograph (original photograph in possession of Atlanta Housing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original photograph in possession of Atlanta Housing Authority, Atlanta, GA). Photographer unknown, June, 1940. VIEW OF STORE AND ADMINISTRATION BUILDING (RIGHT), BUILDING 4 (CENTER) AND BUILDING 5 RIGHT, FROM NORTH FACING SOUTH ALONG TECHWOOD DRIVE. - Techwood Homes (Public Housing), Bounded by North Avenue, Parker Street, William Street & Lovejoy Street, Atlanta, Fulton County, GA

  19. 18 Percent of Pregnant Women Drink Alcohol during Early Pregnancy


    ... have physical, learning, and/or behavior problems, including Fetal Alcohol Spectrum Disorder (FASD) . 1 These problems are caused by alcohol ... 4. Centers for Disease Control and Prevention. (2011). Fetal alcohol spectrum disorders (FASDs): Facts about FASDs. Retrieved from http: / / www. ...

  20. Xyloglucan oligosaccharides promote growth and activate cellulase: Evidence for a role of cellulase in cell expansion. [Pisum sativum L

    SciTech Connect

    McDougall, G.J.; Fry, S.C. )


    Oligosaccharides produced by the action of fungal cellulase on xyloglucans promoted the elongation of etiolated pea (Pisum sativum L.) stem segments in a straight-growth bioassay designed for the determination of auxins. The oligosaccharides were most active at about 1 micromolar. We tested the relative growth-promoting activities of four HPLC-purified oligosaccharides which shared a common glucose{sub 4} {center dot} xylose{sub 3} (XG7) core. The substituted oligosaccharides XG8 (glucose{sub 4} {center dot} xylose{sub 3} {center dot} galactose) and XG9n (glucose{sub 4} {center dot} xylose{sub 3} {center dot} galactose{sub 2}) were more effective than XG7 itself and XG9 (glucose{sub 4} {center dot} xylose{sub 3} {center dot} galactose {center dot} fucose). The same oligosaccharides also promoted the degradation, assayed viscometrically, of xyloglucan by an acidic cellulase from bean (Phaseolus vulgaris L.) leaves. The oligosaccharides were highly active at 10{sup {minus}4} molar, causing up to a fourfold increase in activity, but the effect was still detectable at 1 micromolar. Those oligosaccharides (XG8 and XG9n) which best promoted growth, stimulated cellulase activity to the greatest extent. The oligosaccharides did not stimulate the action of the cellulase in an assay based on the conversion of ({sup 3}H)xyloglucan to ethanol-soluble fragments. This suggests that the oligosaccharides enhanced the midchain hydrolysis of xyloglucan molecules (which would rapidly reduce the viscosity of the solution), at the expense of cleavage near the termini (which would yield ethanol-soluble products).

  1. Gamma-ray burst of November 19, 1978

    SciTech Connect

    Zenchenko, V.M.; Kuznetsov, A.V.; Mersov, G.A.; Estulin, I.V.; Vedrenne, G.; Niel, M.; Hurley, K.


    The ..gamma..-ray burst recorded on November 19, 1978, by the Venera 11 and Venera 12 space probes and the Prognoz 7 satellite is described. The source of this burst is confined to an ellipse measuring 0'.84 x 15'.4, centered at ..cap alpha..=19/sup 0/.064, delta=-28/sup 0/.858 (1950.0). No identification can yet be made between the source and any stellar object.

  2. Hydrothermal Formation Of Hemi-hydrate Calcium Sulfate Whiskers In The Presence Of Additives

    SciTech Connect

    Luo, K. B.; Li, C. M.; Li, H. P.; Ning, P.; Xiang, L.


    The influence of addictives on the hydrothermal formation of hemi-hydrate calcium sulfate (CaSO{sub 4{center_dot}}0.5H{sub 2}O) whiskers were discussed in this paper, using CaCl{sub 2} and Na{sub 2}SO{sub 4} as the reactants. The presence of NaCl, CaCl{sub 2} or Na{sub 2}SO{sub 4} increased the concentrations of Ca{sup 2+} and SO{sub 4}{sup 2-}, leading to the formation of CaSO{sub 4{center_dot}}0.5H{sub 2}O whiskers with aspect ratio lower than 50. The one dimensional growth of CaSO{sub 4{center_dot}}0.5H{sub 2}O whiskers was enhanced in water with no additives owing to the low super-saturation, leading to the formation of uniform whiskers with a length of 200-2000 {mu}m and an aspect ratio higher than 100.

  3. Preparation, structure, and luminescence of dinuclear lanthanide complexes of a novel imine-amine phenolate macrocycle

    SciTech Connect

    Matthews, K.D.; Kahwa, I.A. ); Williams, D.J. )


    Metal-free condensation of 2,6-diformyl-p-cresol with 3,6-dioxa-1,8-octanediamine followed by reduction with sodium tetrahydroborate and addition of lanthanide(III) nitrate salts, in that order, yield (slowly) crystalline dinuclear complexes of a novel imine-amine phenolate macrocycle 2. The decacoordination geometry of the identical Pr[sup 3+] ions in a C[sub 2v] 4A,6B-extended dodecahedron made up of two bidentate NO[sub 3]-ions, two phenolate and two either oxygens, and one imine and one amine nitrogens. Dinuclear lanthanide complexes of 2 appear to be more stable than those of the totally reduced chelate 2 in alcoholic media. The Tb[sub 2]2(NO[sub 3])[sub 4][center dot]1.2CH[sub 3]-OH and (La[sub 0.97]Tb[sub 0.03])[sub 2]2(NO[sub 3])[sub 4][center dot]1.2CH[sub 3]OH compounds exhibit strong Tb[sup 3+] ([sup 5]D[sub 4] [yields] [sup 7]F[sub J]) emission sensitized by the single state of 2 at both 77 and 295 K. No Tb[sup 3+]-Tb[sup 3+] self-quenching or N-H trapping effects are observed at 77 K (decay rate is 598 s[sup [minus]1]); the coordination cavities of 2 are therefore potentially good hosts for Tb[sup 3+] in luminescent diagnostic agents. At room temperature the complex decay kinetics of Tb[sup 3+] in Tb[sub 2]2(NO[sub 3])[sub 4][center dot]1.2CH[sub 3]OH are similar to those of Tb[sub 2]1(NO[sub 3])[sub 4][center dot]H[sub 2]O. But for the dilute complex, (La[sub 0.97]-Tb[sub 0.03])[sub 2]2(NO[sub 3])[sub 4][center dot]1.35CH[sub 3]OH, unusual thermal equilibration of the ligand triplet and Tb[sup 3+] [sup 5]D[sub 4] states occurs at room temperature; the ligand-to-Tb[sup 3+] energy-transfer rate is [approx]4.36 x 10[sup 4] s[sup [minus]1], while Tb[sup 3+]-to-ligand back-energy-transfer is [approx]7.1 x 10[sup 4] s[sup [minus]1].

  4. From dihydrated iron(III) phosphate to monohydrated ammonium-iron(II) phosphate: Solvothermal reaction mediated by acetone-urea mixtures

    SciTech Connect

    Alfonso, Belen F.; Pique, Carmen; Blanco, Jesus A.


    By reaction between synthetic phosphosiderite FePO{sub 4}{center_dot}2H{sub 2}O, urea (NH{sub 2}){sub 2}CO, and acetone (CH{sub 3}){sub 2}CO, we report a novel solvothermal synthesis of polycrystalline NH{sub 4}FePO{sub 4}{center_dot}H{sub 2}O. The preparation of other two individual phases, NH{sub 4}Fe{sub 2}(OH)(PO{sub 4}){sub 2}{center_dot}2H{sub 2}O and NH{sub 4}Fe{sub 2}(PO{sub 4}){sub 2}, is also described. The obtained product is a function of the reaction time and the N/P molar ratio in the reagent mixture, and the existence of structural memory in the dissolution-precipitation processes is discussed. Below 25 K, NH{sub 4}FePO{sub 4}{center_dot}H{sub 2}O behaves magnetically in a complex way, because both ferromagnetic and antiferromagnetic signals are superimposed, suggesting the existence of a canting of iron(II) magnetic moments. - Graphical abstract: Solvothermal synthesis of polycrystalline NH{sub 4}FePO{sub 4}{center_dot}H{sub 2}O is presented. The preparation of other two individual phases, NH{sub 4}Fe{sub 2}(OH)(PO{sub 4}){sub 2}{center_dot}2H{sub 2}O and NH{sub 4}Fe{sub 2}(PO{sub 4}){sub 2} as a function of the N/P molar ratio in the reagent mixture and the reaction time, is also described. Highlights: Black-Right-Pointing-Pointer Solvothermal synthesis of NH{sub 4}FePO{sub 4}{center_dot}H{sub 2}O from an Fe(III) phosphate: reduction process. Black-Right-Pointing-Pointer Formation of two intermediate metastable phases: phase diagram. Black-Right-Pointing-Pointer Thermal decomposition in two steps: mass loss of both water and ammonia. Black-Right-Pointing-Pointer Magnetic behaviour: AF+constant spontaneous magnetization.

  5. Cr{sup 6+}-containing phases in the system CaO-Al{sub 2}O{sub 3}-CrO{sub 4}{sup 2-}-H{sub 2}O at 23 Degree-Sign C

    SciTech Connect

    Poellmann, Herbert


    Synthesis and investigation of lamellar calcium aluminium hydroxy salts was performed to study the incorporation of chromate ions in the interlayer of lamellar calcium aluminium hydroxy salts. Different AFm-phases (calcium aluminate hydrate with alumina, ferric oxide, mono-anion phase) containing chromate were synthesized. These AFm-phases belong to the group of layered double hydroxides (LDHs). 3CaO{center_dot}Al{sub 2}O{sub 3}{center_dot}CaCrO{sub 4}{center_dot}nH{sub 2}O and C{sub 3}A{center_dot}1/2Ca(OH){sub 2}{center_dot}1/2CaCrO{sub 4}{center_dot}12H{sub 2}O were obtained as pure phases and their different distinct interlayer water contents and properties determined. Solid solution of chromate-containing phases and tetracalcium-aluminate-hydrate (TCAH) were studied. The uptake of chromate into TCAH from solutions was proven. Chromate contents in solution decrease to <0.2 mg/l. - Graphical abstract: Chromate can be incorporated in LDH-phases with compositions like: 3CaO{center_dot}Al{sub 2}O{sub 3}{center_dot}1/2CaCrO{sub 4}{center_dot}1/2Ca(OH){sub 2}{center_dot}nH{sub 2}O, 3CaO{center_dot}Al{sub 2}O{sub 3}{center_dot}CaCrO{sub 4}{center_dot}nH{sub 2}O, 3CaO{center_dot}Al{sub 2}O{sub 3}{center_dot}1/6CaCrO{sub 4}.{center_dot}5/6Ca(OH){sub 2}{center_dot}nH{sub 2}O, 3CaO{center_dot}Al{sub 2}O{sub 3}(0-x)CaCrO{sub 4}(1-x) Ca(OH){sub 2}{center_dot}12H{sub 2}O, (04}{center_dot}nH{sub 2}O and C{sub 3}A{center_dot}1/2 Ca(OH){sub 2}{center_dot}1/2 CaCrO{sub 4}{center_dot}12 H{sub 2}O are given. Black-Right-Pointing-Pointer Different hydrates of Ca-Al-hydroxysalts (LDH) with chromate-anions synthesized and characterized. Black-Right-Pointing-Pointer Interlayer exchange reaction of 2OH{sup -} and CrO{sub 4}{sup 2-} investigated. Black-Right-Pointing-Pointer Thermal dehydration and change of lattice parameters are given

  6. A Facile Synthesis of Monodisperse Au Nanoparticles and Their Catalysis of CO Oxidation

    SciTech Connect

    Lee, Youngmin; Sun, Shouheng; Wang, Chao; Yin, Hongfeng; Peng, Sheng; Dai, Sheng


    Monodisperse Au nanoparticles (NPs) have been synthesized at room temperature via a burst nucleation of Au upon injection of the reducing agent t-butylamine-borane complex into a 1, 2, 3, 4-tetrahydronaphthalene solution of HAuCl{sub 4} {center_dot} 3H{sub 2}O in the presence of oleylamine. The as-synthesized Au NPs show size-dependent surface plasmonic properties between 520 and 530 nm. They adopt an icosahedral shape and are polycrystalline with multiple-twinned structures. When deposited on a graphitized porous carbon support, the NPs are highly active for CO oxidation, showing 100% CO conversion at -45 C.

  7. Snythesis and characterization of the first main group oxo-centered trinuclear carboxylate

    NASA Technical Reports Server (NTRS)

    Duraj, Stan A.


    The synthesis and structural characterization of the first main group oxo-centered, trinuclear carboxylato-bridged species is reported, namely (Ga3(mu(sub 3)-O) (mu-O2CC6H5)6 (4-Mepy)3) GaCl4 center dot 4-Mepy (compound 1), where 4-Mepy is 4-methylpyridine. Compound 1 is a main group example of a well-established class of complexes, referred to as 'basic carboxylates' of the general formula (M3(mu(sub 3)-O)(mu-O2CR)6L3)(+), previously observed only for transition metals.


    SciTech Connect



    The results of atomic beam production studies are presented. Improved cooling of the atoms before jet formation in the dissociator cold nozzle apparently reduces the atomic beam velocity spread and improves beam focusing conditions. A carefully designed sextupole separating (and focusing) magnet system takes advantage of the high brightness source. As a result a record beam intensity of a 12.4 {center_dot} 10{sup 16} atoms/s was obtained within 10 mm acceptance at the collision point. The results of the polarization dilution factor measurements (by the hydrogen molecules at the collision point) are also presented.

  9. Thermomechanical and thermoelectrical properties of vanadyl phosphate dihydrate

    SciTech Connect

    Zima, V.; Benes, L.; Malek, J.; Vlcek, M. . Joint Lab. of Solid State Chemistry Univ. of Pardubice )


    Thermoelectric power and XRD of layered VOPO[sub 4][center dot]2H[sub 2]O have been studied for dependence on temperature. The results of thermomechanical analysis (i.e. thermal changes of the thickness of the crystal across the layers) correspond to the changes of basal spacing during heating. The values of the dehydration temperatures have been determined. The conductivity caused by positive charge carriers is predominant in vanadyl phosphate hydrates, whereas conductivity in anhydrous VOPO[sub 4] is electronic, as it follows from the thermoelectric power measurements.

  10. Observation of Instabilities of Coherent Transverse Ocillations in the Fermilab Booster

    SciTech Connect

    Alexahin, Y.; Eddy, N.; Gianfelice-Wendt, E.; Lebedev, V.; Marsh, W.; Pellico, W.; Triplett, K.; /Fermilab


    The Fermilab Booster - built more than 40 years ago - operates well above the design proton beam intensity of 4 {center_dot} 10{sup 12} ppp. Still, the Fermilab neutrino experiments call for even higher intensity exceeding 5.5 {center_dot} 10{sup 12} ppp. A multitude of intensity related effects must be overcome in order to meet this goal including suppression of coherent dipole instabilities of transverse oscillations which manifest themselves as a sudden drop in the beam current. In this report we present the results of observation of these instabilities at different tune, coupling and chromaticity settings and discuss possible cures.

  11. On the role of the VO(H{sub 2}PO{sub 4}){sub 2} precursor for n-butane oxidation into maleic anhydride

    SciTech Connect

    Sananes, M.T. |; Hutchings, G.J.; Volta, J.C.


    The catalytic role of VO(H{sub 2}PO{sub 4}){sub 2}, the precursor of the VO(PO{sub 3}){sub 2} phase, has been studied for N-butane oxidation to maleic anhydride. By comparison with the activated VPO catalyst, derived from the VOHPO{sub 4} {center_dot} 0.5H{sub 2}O precursor phase, VO(H{sub 2}PO{sub 4}){sub 2} gives a highly selective final catalyst. The total oxidation products CO and CO{sub 2} are not observed under any of the conditions examined, a result confirmed by extensive catalyst testing and carbon mass balances. The final catalyst derived from VO(H{sub 2}PO{sub 4}){sub 2} has a low surface area, ca. 1 m{sup 2}/g, and consequently demonstrates low specific activity on the basis of n-butane conversion per unit mass. However, the intrinsic activity (activity per unit surface area) is found to be higher than that for catalysts derived from VOHPO{sub 4}{center_dot}0.5H{sub 2}O. Since some VO(H{sub 2}PO{sub 4}){sub 2} is present in VOHPO{sub 4}{center_dot}0.5H{sub 2}O, which is the precursor of the industrial catalyst, the results of this study complicate the simple model in which the (VO){sub 2}O{sub 7} phase derived from VOHPO{sub 4} {center_dot}0.5H{sub 2}O is responsible for the selective oxidation of n-butane. The observation that the precursor VO(H{sub 2}PO{sub 4}){sub 2} can generate catalysts of high specific activity and of total selectivity to partial oxidation products might provide a useful insight into the design of a new series of high activity and high selectivity partial oxidation catalysts. 36 refs., 12 figs., 2 tabs.

  12. Probing the Pu4 + magnetic moment in PuF4 with 19F NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Capan, Cigdem; Dempsey, Richard J.; Sinkov, Sergey; McNamara, Bruce K.; Cho, Herman


    The magnetic fields produced by Pu4 + centers have been measured by 19F NMR spectroscopy to elucidate the Pu-F electronic interactions in polycrystalline PuF4. Spectra acquired at applied fields of 2.35 and 7.05 T reveal a linear scaling of the 19F line shape. A model is presented that treats the line broadening and shifts as due to dipolar fields produced by Pu valence electrons in localized noninteracting orbitals. Alternative explanations for the observed line shape involving covalent Pu-F bonding, superexchange interactions, and electronic configurations with enhanced magnetic moments are considered.

  13. Isopiestic Determination of the Osmotic and Activity Coefficients of Li2SO4(aq) at T = 298.15 and 323.15 K, and Representation with an Extended Ion-interaction (Pitzer) model

    SciTech Connect

    Rard, J A; Clegg, S L; Palmer, D A


    Isopiestic vapor-pressure measurements were made for Li{sub 2}SO{sub 4}(aq) from 0.1069 to 2.8190 mol {center_dot} kg{sup -1} at 298.15 K, and from 0.1148 to 2.7969 mol {center_dot} kg{sup -1} at 323.15 K, with NaCl(aq) as the reference standard. Published thermodynamic data for this system were reviewed, recalculated for consistency, and critically assessed. The present results and the more reliable published results were used to evaluate the parameters of an extended version of Pitzer's ion-interaction model with an ionic-strength dependent third virial coefficient, as well as those of the standard Pitzer model, for the osmotic and activity coefficients at both temperatures. Published enthalpies of dilution at 298.15 K were also analyzed to yield the parameters of the ion-interaction models for the relative apparent molar enthalpies of dilution. The resulting models at 298.15 K are valid to the saturated solution molality of the thermodynamically stable phase Li{sub 2}SO{sub 4} {center_dot} H{sub 2}O(cr). Solubilities of Li{sub 2}SO{sub 4} {center_dot} H{sub 2}O(cr) at 298.15 K were assessed, and the selected value of m(sat.) = 3.13 {+-} 0.04 mol {center_dot} kg{sup -1} was used to evaluate the thermodynamic solubility product K{sub s}(Li{sub 2}SO{sub 4} {center_dot} H{sub 2}O, cr, 298.15 K) = (2.62 {+-} 0.19) and a CODATA-compatible standard molar Gibbs energy of formation {Delta}{sub f}G{sub m}{sup o} (Li{sub 2}SO{sub 4} {center_dot} H{sub 2}O, cr, 298.15 K) = -(1564.6 {+-} 0.5) kJ {center_dot} mol{sup -1}.

  14. Performance of direct contact latent heat storage unit

    SciTech Connect

    Farid, M.; Yacoub, K. )


    The performance of direct contact latent heat storage unit has been investigated in a glass column having an inside diameter and length of 0.2 m and 1.5 m respectively. Kerosene, as a heat transfer fluid, was bubbled through the continuous phase which was a solution of one of the hydrated salts: Na{sub 2}CO{sub 3}{center dot}10H{sub 2}O, Na{sub 2}SO{sub 4}{center dot}10H{sub 2}O, and Na{sub 2}HPO{sub 4}{center dot}12H{sub 2}O. The continuous phase temperature at different heights together with the kerosene inlet and outlet temperatures were measured with time during both heat charge and discharge. Theoretical prediction of the performance of the unit has been achieved employing the model for drop with internal circulation which was used to evaluate the transfer efficiency. Thermal efficiency of the nit was found to increase with the larger column. A sharp decrease in the magnitude of the heat transfer coefficient was observed soon after crystallization started. The coefficient increased significantly at higher kerosene flow rates due to the information of smaller bubbles.

  15. An international survey of surveillance schemes for unaffected BRCA1 and BRCA2 mutation carriers.


    Madorsky-Feldman, Dana; Sklair-Levy, Miri; Perri, Tamar; Laitman, Yael; Paluch-Shimon, Shani; Schmutzler, Rita; Rhiem, Kerstin; Lester, Jenny; Karlan, Beth Y; Singer, Christian F; Van Maerken, Tom; Claes, Kathleen; Brunet, Joan; Izquierdo, Angel; Teulé, Alex; Lee, Jong Won; Kim, Sung-Won; Arun, Banu; Jakubowska, Anna; Lubinski, Jan; Tucker, Katherine; Poplawski, Nicola K; Varesco, Liliana; Bonelli, Luigina Ada; Buys, Saundra S; Mitchell, Gillian; Tischkowitz, Marc; Gerdes, Anne-Marie; Seynaeve, Caroline; Robson, Mark; Kwong, Ava; Tung, Nadine; Tessa, Nalven; Domchek, Susan M; Godwin, Andrew K; Rantala, Johanna; Arver, Brita; Friedman, Eitan


    Female BRCA1/BRCA2 mutation carriers are at substantially increased risk for developing breast and/or ovarian cancer, and are offered enhanced surveillance including screening from a young age and risk-reducing surgery (RRS)-mastectomy (RRM) and/or salpingo-oophorectomy (RRSO). While there are established guidelines for early detection of breast cancer in high-risk women who have not undergone RRM, there are less developed guidelines after RRM. We evaluated the schemes offered before and after RRS in internationally diverse high-risk clinics. An e-mailed survey was distributed to high-risk clinics affiliated with CIMBA. Overall, 22 centers from 16 countries responded. Pre RRS surveillance schemes overwhelmingly included breast imaging (primarily MRI) from 18 to 30 years and clinical breast exam (CBE) at 6-12 month intervals. For ovarian cancer, all but 6 centers offered semiannual/annual gynecological exam, transvaginal ultrasound, and CA 125 measurements. Post RRM, most centers offered only annual CBE while 4 centers offered annual MRI, primarily for substantial residual breast tissue. After RRSO only 4 centers offered specific gynecological surveillance. Existing guidelines for breast/ovarian cancer detection in BRCA carriers are being applied pre RRS but are not globally harmonized, and most centers offer no specific surveillance post RRS. From this comprehensive multinational study it is clear that evidence-based, long-term prospective data on the most effective scheme for BRCA carriers post RRS is needed. PMID:27117159

  16. Gallium hole traps in irradiated KTiOPO{sub 4}:Ga crystals

    SciTech Connect

    Grachev, V.; Meyer, M.; Malovichko, G.; Hunt, A. W.


    Nominally pure and gallium doped single crystals of potassium titanyl phosphate (KTiOPO{sub 4}) have been studied by Electron Paramagnetic Resonance at low temperatures before and after irradiation. Irradiation with 20 MeV electrons performed at room temperature and liquid nitrogen temperature caused an appearance of electrons and holes. Gallium impurities act as hole traps in KTiOPO{sub 4} creating Ga{sup 4+} centers. Two different Ga{sup 4+} centers were observed, Ga1 and Ga2. The Ga1 centers are dominant in Ga-doped samples. For the Ga1 center, a superhyperfine structure with one nucleus with nuclear spin ½ was registered and attributed to the interaction of gallium electrons with a phosphorus nucleus or proton in its surrounding. In both Ga1 and Ga2 centers, Ga{sup 4+} ions substitute for Ti{sup 4+} ions, but with a preference to one of two electrically distinct crystallographic positions (site selective substitution). The Ga doping eliminates one of the shortcomings of KTP crystals—ionic conductivity of bulk crystals. However, this does not improve significantly the resistance of the crystals to electron and γ-radiation.

  17. Catalytic activity of transition metal-N4 moieties in graphene toward the oxygen reduction reaction: A DFT study

    NASA Astrophysics Data System (ADS)

    Orellana, Walter


    The search for non-precious metal cathode catalysts for the oxygen reduction reaction (ORR) that replace platinum in proton exchange membrane fuel cells is one of the main challenges toward the use of hydrogen as clean energy for transportation. Most current works on ORR catalysts focuses on N-coordinated iron in a carbon matrix. Although the nature of the active site is still a mystery, different carbon-supported Fe-Nx active sites have been proposed. In this work, The O2 dissociation after the interaction with the metal center of M-N4 moieties in graphene (with M = Mn, Fe, and Co) are addressed by density functional theory calculations. Both, saddle points and minimum energy paths for the ORR in the allowed spin channels have been identified. Our results show that the Mn-N4 center in graphene exhibits the lowest activation barrier in all spin channel, less than 1 eV, suggesting improved ORR activity, while for Fe-N4 and Co-N4 they range between 1.2 and 1.6 eV. Our calculations suggest that the O2 dissociation would proceed through different spin channel which would increase the reaction rate, particularly for Mn-O2 and Fe-O2 moieties. We also investigate energetically favorable routes to incorporate the M-N4 centers in graphene. Work supported by FONDECYT under Grant No. 1090489

  18. Geographic information systems. A new tool in environmental epidemiology.


    Ward; Nuckols; Weigel; Maxwell; Cantor; Miller


    PURPOSE: Geographic Information Systems (GIS) are useful tools for identifying populations with potential exposure to environmental contaminants. Using a GIS, features of the local environment around an individual's home, work, or school can be described. We present two examples illustrating methods and issues in identifying populations potentially exposed to agricultural pesticides and to toxic releases from the Toxic Release Inventory (TRI).METHODS: We used USDA Farm Service Agency records as ground reference data to classify a late summer 1984 satellite image into crop species in 3 counties in Nebraska. We located residences from a case-control study of non-Hodgkin's lymphoma (NHL) on the crop maps and calculated the distance to crop fields. Residences from a 4-center study of NHL were mapped and the distance to TRI sites was determined.RESULTS: Twenty-two percent of residences had crop fields within 500 meters of the home, an intermediate distance for the range of drift effects from pesticide applications. After accounting for the extent of primary drift from ground applications of pesticides, we estimated that 30 percent of residences were potentially exposed to crop pesticides. In the 4-center study, residence locations determined by address-matching methods and by a global positioning system were compared; the population 1 mile from specific TRI sites is described.CONCLUSIONS: These examples demonstrate the utility of a GIS in environmental epidemiology studies. A GIS can be a useful addition to questionnaire and other methods of exposure assessment in health studies. PMID:11018420

  19. High-temperature annealing of optical centers in type-I diamond

    SciTech Connect

    Collins, Alan T.; Connor, Alex; Ly, C.-H.; Shareef, Abdulla; Spear, Paul M.


    Diamonds previously subjected to radiation damage have been annealed at temperatures up to 1750 deg. C at ambient pressure, and at 2300 deg. C using a stabilizing pressure of 5 GPa. The results have been compared with those from similar measurements using natural brown diamonds. The investigation has led to an improved understanding of the commercial process for enhancing the color of brown diamonds by high-pressure, high-temperature (HPHT) annealing. The study has confirmed that the H4 center is less stable than the H3 center, and shown that the destruction of the H4 center in irradiated type-IaB diamonds coincides with the formation of a number of optical centers found to occur naturally in brown diamonds. In type-IaA diamonds the annealing out of the H1b absorption coincides with the production of H2 centers. Annealing measurements on brown diamonds indicate that the plastic deformation, associated with the brown color, occurred at a late stage in the diamonds' history. Optical centers, such as H3 and (N-V){sup -}, that are produced in brown diamonds by HPHT annealing, are destroyed by this process in irradiated dislocation-free diamonds. Formation of these centers during the HPHT annealing of brown diamonds occurs as a result of the release of vacancies from the dislocations, and the present results therefore indicate that the production of these centers is a dynamic process with the generation and annealing in competition.

  20. A single iron site confined in a graphene matrix for the catalytic oxidation of benzene at room temperature

    PubMed Central

    Deng, Dehui; Chen, Xiaoqi; Yu, Liang; Wu, Xing; Liu, Qingfei; Liu, Yun; Yang, Huaixin; Tian, Huanfang; Hu, Yongfeng; Du, Peipei; Si, Rui; Wang, Junhu; Cui, Xiaoju; Li, Haobo; Xiao, Jianping; Xu, Tao; Deng, Jiao; Yang, Fan; Duchesne, Paul N.; Zhang, Peng; Zhou, Jigang; Sun, Litao; Li, Jianqi; Pan, Xiulian; Bao, Xinhe


    Coordinatively unsaturated (CUS) iron sites are highly active in catalytic oxidation reactions; however, maintaining the CUS structure of iron during heterogeneous catalytic reactions is a great challenge. Here, we report a strategy to stabilize single-atom CUS iron sites by embedding highly dispersed FeN4 centers in the graphene matrix. The atomic structure of FeN4 centers in graphene was revealed for the first time by combining high-resolution transmission electron microscopy/high-angle annular dark-field scanning transmission electron microscopy with low-temperature scanning tunneling microscopy. These confined single-atom iron sites exhibit high performance in the direct catalytic oxidation of benzene to phenol at room temperature, with a conversion of 23.4% and a yield of 18.7%, and can even proceed efficiently at 0°C with a phenol yield of 8.3% after 24 hours. Both experimental measurements and density functional theory calculations indicate that the formation of the Fe═O intermediate structure is a key step to promoting the conversion of benzene to phenol. These findings could pave the way toward highly efficient nonprecious catalysts for low-temperature oxidation reactions in heterogeneous catalysis and electrocatalysis. PMID:26665170

  1. Synthesis, structure and luminescence property of 2D lanthanide complexes with 3-fluorophthalate and oxalate

    SciTech Connect

    Cha, Yu-E; Li, Xia; Song, Shuang


    Complexes [Ln{sub 2}(fpht){sub 2}(ox)(H{sub 2}O){sub 4}]{center_dot}H{sub 2}O (Ln=Sm 1, Eu 2, Tb 3 and Dy 4; fpht=3-fluorophthalate and ox=oxalate) have been synthesized and structurally characterized by single crystal X-ray diffraction. The four complexes possess similar 2D framework structures constructed from Ln-fpht double-stranded helices and ox linkages. Complexes 2 and 3 display the characteristic emission {sup 5}D{sub 0}{yields}{sup 7}F{sub J} (J=0-4) transitions of Eu(III) ion and {sup 5}D{sub 4}{yields}{sup 7}F{sub J} (J=6-3) transitions of Tb(III) ion, respectively. The emission decay curves reveal a monoexponential behavior yielding the lifetime values of 0.266{+-}0.002 ms for 2 and 0.733{+-}0.002 ms for 3. The emission spectrum of 1 shows three weak bands corresponding to the characteristic emission {sup 4}G{sub 5/2}{yields}{sup 6}H{sub 5/2}, {sup 4}G{sub 5/2}{yields}{sup 6}H{sub 7/2} and {sup 4}G{sub 5/2}{yields}{sup 6}H{sub 9/2} transitions of Sm(III) ion. The emission spectrum of 4 displays a broad band centered at 438 nm, which comes from the {pi}{sup Low-Asterisk }-{pi} transition of the ligand. - Graphical abstract: Complexes [Ln{sub 2}(fpht){sub 2}(ox)(H{sub 2}O){sub 4}]{center_dot}H{sub 2}O (fpht=3-fluorophthalate, ox=oxalate) possess 2D structures. Sm(III), Eu(III) and Tb(III) complexes show the characteristic fluorescent emission of the Ln(III). Dy(III) complex displays ligand-based luminescent behavior. Highlights: Black-Right-Pointing-Pointer [Ln{sub 2}(fpht){sub 2}(ox)(H{sub 2}O){sub 4}]{center_dot}H{sub 2}O (fpht=3-fluorophthalate; ox=oxalate) show 2D structures. Black-Right-Pointing-Pointer The 2D structures are constructed from Ln-fpht double-stranded helices and ox linkage. Black-Right-Pointing-Pointer The Sm(III), Eu(III) and Tb(III) complexes show the characteristic emission of the Ln(III) ions. Black-Right-Pointing-Pointer Dy(III) complex displays ligand-based luminescent behavior.

  2. Critical Role of Water Content in the Formation and Reactivity of Uraniu, Neptunium, and Plutonium Iodates Under Hydrothermal Conditions: Implications for the Oxidative Dissolution of Spent Nuclear Fuel

    SciTech Connect

    Bray, T. H.; Ling, Jie; Choi, E- Sang; Brooks, James S.; Beitz, James V.; Sykora, Richard E.; Haire, Richard {Dick} G; Stanbury, David M.; Albrecht-Schmitt, Thomas E.


    The reactions of {sup 237}NpO{sub 2} with excess iodate under acidic hydrothermal conditions result in the isolation of the neptunium(IV), neptunium(V), and neptunium(VI) iodates, Np(IO{sub 3}){sub 4}, Np(IO{sub 3}){sub 4}{center_dot}nH{sub 2}O{center_dot}nHIO{sub 3}, NpO2(IO3), NpO2(IO3)2(H2O), and NpO{sub 2}(IO{sub 3}){sub 2}{center_dot}H{sub 2}O, depending on both the pH and the amount of water present in the reactions. Reactions with less water and lower pH favor reduced products. Although the initial redox processes involved in the reactions between {sup 237}NpO{sub 2} or {sup 242}PuO{sub 2} and iodate are similar, the low solubility of Pu(IO{sub 3}){sub 4} dominates product formation in plutonium iodate reactions to a much greater extent than does Np(IO{sub 3}){sub 4} in the neptunium iodate system. UO{sub 2} reacts with iodate under these conditions to yield uranium(VI) iodates solely. The isotypic structures of the actinide(IV) iodates, An(IO{sub 3}){sub 4} (An = Np, Pu), are reported and consist of one-dimensional chains of dodecahedral An(IV) cations bridged by iodate anions. The structure of Np(IO3)4{center_dot}nH2O{center_dot}nHIO3 is constructed from NpO9 tricapped-trigonal prisms that are bridged by iodate into a polar three-dimensional framework structure. Second-harmonic-generation measurements on a polycrystalline sample of the Th analogue of Np(IO{sub 3}){sub 4}{center_dot}nH{sub 2}O{center_dot}nHIO{sub 3} reveal a response of approximately 12x that of {alpha}-SiO{sub 2}. Single-crystal magnetic susceptibility measurements of Np(IO{sub 3}){sub 4} show magnetically isolated Np(IV) ions.

  3. A standardized protocol to reduce cerebrospinal fluid shunt infection: The Hydrocephalus Clinical Research Network Quality Improvement Initiative

    PubMed Central

    Kestle, John R. W.; Riva-Cambrin, Jay; Wellons, John C.; Kulkarni, Abhaya V.; Whitehead, William E.; Walker, Marion L.; Oakes, W. Jerry; Drake, James M.; Luerssen, Thomas G.; Simon, Tamara D.; Holubkov, Richard


    Object Quality improvement techniques are being implemented in many areas of medicine. In an effort to reduce the ventriculoperitoneal shunt infection rate, a standardized protocol was developed and implemented at 4 centers of the Hydrocephalus Clinical Research Network (HCRN). Methods The protocol was developed sequentially by HCRN members using the current literature and prior institutional experience until consensus was obtained. The protocol was prospectively applied at each HCRN center to all children undergoing a shunt insertion or revision procedure. Infections were defined on the basis of CSF, wound, or pseudocyst cultures; wound breakdown; abdominal pseudocyst; or positive blood cultures in the presence of a ventriculoatrial shunt. Procedures and infections were measured before and after protocol implementation. Results Twenty-one surgeons at 4 centers performed 1571 procedures between June 1, 2007, and February 28, 2009. The minimum follow-up was 6 months. The Network infection rate decreased from 8.8% prior to the protocol to 5.7% while using the protocol (p = 0.0028, absolute risk reduction 3.15%, relative risk reduction 36%). Three of 4 centers lowered their infection rate. Shunt surgery after external ventricular drainage (with or without prior infection) had the highest infection rate. Overall protocol compliance was 74.5% and improved over the course of the observation period. Based on logistic regression analysis, the use of BioGlide catheters (odds ratio [OR] 1.91, 95% CI 1.19–3.05; p = 0.007) and the use of antiseptic cream by any members of the surgical team (instead of a formal surgical scrub by all members of the surgical team; OR 4.53, 95% CI 1.43–14.41; p = 0.01) were associated with an increased risk of infection. Conclusions The standardized protocol for shunt surgery significantly reduced shunt infection across the HCRN. Overall protocol compliance was good. The protocol has established a common baseline within the Network, which will

  4. Synthetic pathways to vanadyl organophosphonates through aqueous media

    SciTech Connect

    Gendraud, P.; Bigey, L.; Roy, M.E. de; Besse, J.P.


    Synthesis of vanadyl(IV) organophosphonates VORPO{sub 3}{center_dot}nH{sub 2}O (with R = CH{sub 3}, C{sub 2}H{sub 5}, C{sub 6}H{sub 5}) has been investigated by reaction of VOSO{sub 4}{center_dot}5H{sub 2}O + RPO{sub 3}H{sub 2} under refluxing conditions in aqueous media. The influence of different parameters is discussed, and compounds are characterized by X-ray powder diffraction, TGA, IR, XANES, and EXAFS. For example, three crystallographic forms of VOC{sub 6}H{sub 5}PO{sub 3}{center_dot}2H{sub 2}O obtained differ from each other in the location of the trans water molecule in the layered structure.

  5. Interaction Between Nitrogen And Hydrocarbons In Magnetized Plasmas

    SciTech Connect

    Cwiklinski, A.; Markin, A.; Baudach, M.; Bohmeyer, W.


    The deposition of amorphous hydrocarbon (a-C:H) films and the influence of nitrogen on these films were studied. The experiments were performed in low temperature plasmas with T{sub e} = 3...6 eV and n{sub e} = 1{center_dot}10{sup 16}...4{center_dot}10{sup 17} m{sup -3}. The ratio between injected nitrogen and methane was varied as well as the substrate temperature and the neutral gas pressure. Additionally, the deposition distribution as a function of distance was determined. In situ measurements of the a-C:H growth rate show that the carbon redeposition can be suppressed completely by nitrogen injection (scavenger effect)

  6. Fourier transform infrared spectroscopy of size-segregated aerosol deposits on foil substrates.


    Hopey, Judith A; Fuller, Kirk A; Krishnaswamy, Venkataramanan; Bowdle, David; Newchurch, Michael J


    A method based on Fourier transform infrared (FTIR) double-pass transmittance spectroscopy was developed for determining functional group loading in size-segregated ambient aerosol deposits. The impactor employed for sample collection utilized rotating stages, which produced uniform particulate matter (PM) deposits on standard Al foil substrates. Each sample was analyzed without extraction using an FTIR spectrometer equipped with a reflectometer accessory. The use of the reflectometer obviated the need for infrared window materials as substrates. (NH(4))(2)SO(4) aerosol generated under laboratory conditions were used to calibrate deposit mass to the band strength of the relatively isolated nu(4) bending mode of SO(2-)(4) centered near 620 cm(-1). Atmospheric PM was sampled during the summer of 2004 in Huntsville, Ala. Sulfate concentrations determined in this initial study correlated well with measurements made by collocated EPA air samplers. PMID:18449290

  7. Luminescence properties of Cr-doped silica sol gel glasses

    NASA Astrophysics Data System (ADS)

    Strek, Wieslaw; Lukowiak, Edward; Deren, Przemyslaw J.; Maruszewski, K.; Trabjerg, Ib; Koepke, Czeslaw; Malashkevich, G. E.; Gaishun, Vladimir E.


    The emission of Cr-doped silica glass obtained by the sol- gel method is characterized by an orange broad band with a maximum at 610 nm. Its nature is examined by the absorption, excited state absorption, emission, excitation and lifetime measurements over a wide range of temperature and for different concentration of Cr ions. Our measurement show that in spite of fact that the absorption properties of Cr- doped silica sol-gel glass are predominantly associated with Cr4+ centers, the observed in visible range emission can be assigned neither to Cr3+ nor to Cr4+ ions. The discussion of the nature of observed emission was carried out for all possible valencies of the Cr ions. In conclusion is suggested that it may be ascribed to the transitions on the monovalent Cr1+ ion. The reducing agents occurring during the sol-gel process and leading to lowering the Cr valency are discussed.

  8. Large Grain Superconducting RF Cavities at DESY

    SciTech Connect

    Singer, W.; Brinkmann, A.; Ermakov, A.; Iversen, J.; Kreps, G.; Matheisen, A.; Proch, D.; Reschke, D.; Singer, X.; Spiwek, M.; Wen, H.; Brokmeier, H. G.


    The DESY R and D program on cavities fabricated from large grain niobium explores the potential of this material for the production of approx. 1000 nine-cell cavities for the European XFEL. The program investigates basic material properties, comparing large grain material to standard sheet niobium, as well as fabrication and preparation aspects. Several single-cell cavities of TESLA shape have been fabricated from large grain niobium. A gradient up to 41 MV/m at Q0 = 1.4{center_dot}1010 (TB = 2K) was measured after electropolishing. The first three large grain nine-cell cavities worldwide have been produced under contract of DESY with ACCEL Instruments Co. The first tests have shown that all three cavities reach an accelerating gradient up to 30 MV/m after BCP (Buffered Chemical Polishing) treatment, what exceeds the XFEL requirements for RF test in the vertical cryostat.

  9. The antioxidant effect of derivatives pyroglutamic lactam

    SciTech Connect

    Rohadi, Atisya; Lazim, Azwani Mat; Hasbullah, Siti Aishah


    Diphenylpicrylhydrazyl (DPPH) is widely used for quickly accessing the ability of polyphenols to transfer labile H atoms to radicals. The antioxidant activity of all the synthesized compounds was screened by DPPH method. Compound (4) showed 54% antioxidant potential while all other compounds were found to have moderate to have moderate to mild antioxidant activity ranging from 47–52%. Pyroglutamic lactams have been synthesized stereoselectively in racemic form from levulinic acid as bifunctional adduct using convertible isocyanide in one-pot Ugi 4-center-3-component condensation reaction (U-4C-3CR). The product formed provides biologically interesting products in excellent yields in a short reaction time. The structures of the synthesized compounds were elucidated using spectroscopic data and elemental analysis.

  10. EXAFS structure and electrical properties of lithium niobium phosphate

    SciTech Connect

    Bruque, S.; Martinez Lara, M.; Moreno, L.


    The acidic character of the hydration water in NbOPO{sub 4} {center_dot} 2H{sub 2}O permits the exchange of protons for Li{sup +} ions. The lithium phase annealed at 773 K presents a slightly distorted lattice with respect to the niobium phosphate network, allowing high mobility of the lithium ion. The structural modifications due to Li insertion have been studied by extended X-ray absorption spectroscopy (EXAFS) at the Nb K-edge. The analysis of the EXAFS spectra indicates the presence of an additional oxygen atom close to Nb which is probably not bonded to the framework. The ionic conductivity of the LiNb(OH)OPO{sub 4} phase is high and increases up to 880 K. At higher temperatures, the Li{sup +} ion migrates to a permanent position in the network and the ionic conductivity is then stopped.

  11. Changes in magnetic couplings after chimie douce reactions: Magnetic structures of LiMnXO{sub 4}(OD) (X = P, As)

    SciTech Connect

    Aranda, M.A.G.; Bruque, S.; Attfield, J.P.


    The structural and magnetic changes that take place after the lithium exchange reactions of MnXO{sub 4}{center_dot}D{sub 2}O to give LiMnXO{sub 4} (OD) (X = P, As) have been studied by magnetic susceptibility and variable-temperature neutron diffraction techniques. The crystal structures of the lithium derivatives have been refined at room temperature and 10 K by time-of-flight neutron powder diffraction data using the Rietveld method. These compounds behave as Curie-Weiss paramagnets at high temperatures have been determined from the low-temperature neutron data. Although the four magnetic structures are antiferromagnetic, the magnetic couplings in the Mn-O-Mn infinite chains are ferromagnetic in the lithium derivatives and anti-ferromagnetic in the parent materials. These different magnetic behaviors are explained on the basis of subtle differences in the crystal structures after the lithium exchange reaction.

  12. A biomimetic copper water oxidation catalyst with low overpotential.


    Zhang, Teng; Wang, Cheng; Liu, Shubin; Wang, Jin-Liang; Lin, Wenbin


    Simply mixing a Cu(II) salt and 6,6'-dihydroxy-2,2'-bipyridine (H2L) in a basic aqueous solution afforded a highly active water oxidation catalyst (WOC). Cyclic voltammetry of the solution at pH = 12-14 shows irreversible catalytic current with an onset potential of ~0.8 V versus NHE. Catalytic oxygen evolution takes place in controlled potential electrolysis at a relatively low overpotential of 640 mV. Experimental and computational studies suggest that the L ligand participates in electron transfer processes to facilitate the oxidation of the Cu center to lead to an active WOC with low overpotential, akin to the use of the tyrosine radical by Photosystem II to oxidize the CaMn4 center for water oxidation. PMID:24325734

  13. The use of LANDSAT-1 imagery in mapping and managing soil and range resources in the Sand Hills region of Nebraska

    NASA Technical Reports Server (NTRS)

    Seevers, P. M. (Principal Investigator); Drew, J. V.


    The author has identified the following significant results. Evaluation of ERTS-1 imagery for the Sand Hills region of Nebraska has shown that the data can be used to effectively measure several parameters of inventory needs. (1) Vegetative biomass can be estimated with a high degree of confidence using computer compatable tape data. (2) Soils can be mapped to the subgroup level with high altitude aircraft color infrared photography and to the association level with multitemporal ERTS-1 imagery. (3) Water quality in Sand Hills lakes can be estimated utilizing computer compatable tape data. (4) Center pivot irrigation can be inventoried from satellite data and can be monitored regarding site selection and relative success of establishment from high altitude aircraft color infrared photography. (5) ERTS-1 data is of exceptional value in wide-area inventory of natural resource data in the Sand Hills region of Nebraska.

  14. Chrysolcolla Redefined as Spertiniite

    SciTech Connect

    Farges, Francois; Benzerara, Karim; Brown, Gordon E., Jr.; /Stanford U., Geo. Environ. Sci. /SLAC, SSRL


    XAFS and {mu}-XAFS spectra were collected at the Cu K-edge for seven chrysocolla samples (Peru, USA, and Congo). The results suggest that the local structure around Cu is similar to that in Cu(OH){sub 2} (spertiniite). Cu-L{sub 3} STXM imaging and spectroscopy confirm that the chrysocolla samples examined here consist of mesoscopic Cu(II)-rich domains surrounded by Si-rich domains (in agreement with results from infra-red spectroscopy). Hence, we suggest that chrysocolla, which is generally considered to be orthorhombic with composition (Cu,Al){sub 2}H{sub 2}Si{sub 2}O{sub 5}(OH){sub 4} {center_dot} nH{sub 2}O, is in actually a mesoscopic assemblage composed dominantly of spertiniite (Cu(OH){sub 2}), water and amorphous silica (SiO{sub 2}).

  15. Large-scale synthesis well-dispersed ZnS microspheres and their photoluminescence, photocatalysis properties

    SciTech Connect

    Wang Xinjun Wan Fuquan; Han Kun; Chai Chunxia; Jiang Kai


    Large-scale and well-dispersed ZnS microspheres were prepared by a simple hydrothermal method using ZnSO{sub 4}{center_dot}7H{sub 2}O and SC(NH{sub 2}){sub 2} as main original reactant and poly(vinyl pyrrolidone) (PVP)(Mr {approx} 10,000) as the surfactant. The products were characterized by X-Ray diffraction, scanning electron microscopy and transmission electron microscopy. The growth process involves a special oriented aggregation of PVP stabilized ZnS nanoparticles into microspheres of 1.5 {approx} 2.0 {mu}m in sizes. The photocatalytic activity of as-prepared ZnS microsphere was evaluated by using methylene blue (MB) as a model organic compound. The optical properties of the products were also examined by means of photoluminescence (PL) spectroscopy.

  16. Beneficial role of chloride ions during pickling of steel in sulfuric acid

    SciTech Connect

    Gaur, B.; Singh, T.B.; Singh, D.D.N.


    Sodium chloride was shown to have a beneficial effect on the pickling of mild steel in different concentrations of sulfuric acid at various temperatures and ferrous sulfate (FeSO{sub 4}{center_dot}7H{sub 2}O) accumulations in the bath. Addition of this salt to the H{sub 2}SO{sub 4} bath drastically reduced metal loss, enhanced the pickling rate, removed scale quickly, and improved the surface finish of the pickled material. Addition of hydrochloric acid instead of NaCl, however, accelerated the corrosion rate of mild steel in the uninhibited acid solution but had a negligible effect in the inhibited solution. The beneficial effect of NaCl was discussed based upon electrochemical parameters.

  17. The antioxidant effect of derivatives pyroglutamic lactam

    NASA Astrophysics Data System (ADS)

    Rohadi, Atisya; Lazim, Azwani Mat; Hasbullah, Siti Aishah


    Diphenylpicrylhydrazyl (DPPH) is widely used for quickly accessing the ability of polyphenols to transfer labile H atoms to radicals. The antioxidant activity of all the synthesized compounds was screened by DPPH method. Compound (4) showed 54% antioxidant potential while all other compounds were found to have moderate to have moderate to mild antioxidant activity ranging from 47-52%. Pyroglutamic lactams have been synthesized stereoselectively in racemic form from levulinic acid as bifunctional adduct using convertible isocyanide in one-pot Ugi 4-center-3-component condensation reaction (U-4C-3CR). The product formed provides biologically interesting products in excellent yields in a short reaction time. The structures of the synthesized compounds were elucidated using spectroscopic data and elemental analysis.

  18. Water-soluble organometallic compounds. 2. Catalytic hydrogenation of aldehydes and olefins by new water-soluble 1,3,5-Triaza-7-phosphaadamantane complexes of ruthenium and rhodium

    SciTech Connect

    Darensbourg, D.J.


    The authors describe the chemical preparation of water-soluble phosphine complexes of ruthenium (II) and rhodium (I). The complex RuCl{sub 2}(PTA){sub 4} (2a) and its protonated analog RuCl{sub 2}(PTA){sub 4}{center_dot} 2HCl (2b) and the cis-bis-(phosphine) complex RhCl(PTA){sub 2}{center_dot} 2HCl, derived form the protonation of RhCl(PTA){sub 3} by HCl were characterized by X-ray crystallography. 2a is catalytically active for the conversion of unsaturated aldehydes to unsaturated alcohols and RhCl(PTA){sub 3} catalyzes olefin hydrogenation. 14 refs., 2 figs., 1 tab.

  19. Transport of chromium(VI) through a supported liquid membrane containing tri-n-octylphosphine oxide

    SciTech Connect

    Huang, T.C.; Huang, C.C.; Chen, D.H.


    In this study the transport of chromium(VI) from aqueous solutions of pH 2--4 through a supported liquid membrane (SLM) with tri-n-octylphosphine oxide (TOPO) dissolved in kerosene as a mobile carrier was investigated. The transport flux of Cr(VI) increased with an increase in the concentrations of Cr(VI) in the feed phase and of TOPO in the membrane phase, but with a decrease in pH of the feed phase. Considering the equilibria of various Cr(VI) species in the aqueous phase and of the Cr(VI)-TOPO complexes formed in the membrane phase, a permeation model including the aqueous film diffusion of HCrO{sub 4}{sup {minus}} and Cr{sub 2}O{sub 7}{sup 2{minus}} toward the membrane, the interfacial chemical reaction between them and TOPO, and the membrane diffusion of the Cr(VI)-TOPO complexes ({ovr H{sub 2}CrO{sub 4}{center_dot}(TOPO)} and {ovr H{sub 2}Cr{sub 2}O{sub 7}{center_dot}(TOPO){sub 3}}) was proposed to describe the transport of Cr(VI) through the SLM. By best fitting the transport flux equations of Cr(VI) with the experimental data using the Rosenbrock method, the apparent mass-transfer coefficients of HCrO{sub 4}{sup {minus}} and Cr{sub 2}O{sub 7}{sup 2{minus}} across the aqueous film, and those of {ovr H{sub 2}CrO{sub 4}{center_dot}(TOPO)} and {ovr H{sub 2}Cr{sub 2}O{sub 7}{center_dot}(TOPO){sub 3}} across the membrane phase, were obtained. This work helps to clarify the transport mechanism of Cr(VI) through an SLM.

  20. 18-Membered cyclic esters derived from glycolide and lactide: preparations, structures and coordination to sodium ions

    SciTech Connect

    Chisholm, Malcolm H.; Gallucci, Judith C.; Yin, Hongfeng


    From reactions between glycolide or lactide (4 equiv.) with 4-dimethylaminopyridine, DMAP (1 equiv.) and NaBPh4 (1 equiv.) in benzene at 70 C the cyclic ester adducts (CH{sub 2}C(O)O){sub 6}NaBPh{sub 4} and (CHMeC(O)O){sub 6}NaBPh{sub 4} are formed respectively. The structures of the salts Na[(S,R,S,R,S,R)-(CH{sub 3}CHC(O)O){sub 6}]{sub 2}BPh{sub 4} {center_dot} CH{sub 3}CN and (CH{sub 2}C(O)O){sub 6}NaBPh{sub 4} {center_dot} (CH{sub 3}CN){sub 2} are reported. The cyclic esters were separated by chromatography and the structures of (CH{sub 2}C(O)O){sub 6}, (S,R,R,R,R,R)-(CHMeC(O)O){sub 6} and (S,S,R,R,R,R)-(CHMeC(O)O){sub 6} were determined. The {sup 1}H and {sup 13}C NMR data are reported for one of each of the six enantiomers of (CHMeC(O)O){sub 6} and the two meso isomers. The mechanism for the formation of these 18-membered rings is discussed in terms of an initial reaction between DMAP and NaBPh{sub 4} in hot benzene that produces NaPh and DMAP:BPh{sub 3} in the presence of the monomer lactide. The cyclic esters (CHMeC(O)O){sub 6} can also be obtained from the reaction between polylactide, PLA, in the presence of DMAP and NaBPh{sub 4}. The cyclic esters 3-methyl-1,4-dioxane-2,5-dione and 3,6,6-trimethyl-1,4-dioxane-2,5-dione undergo similar ring enlarging reactions to give cyclic 18-membered ring esters as determined by ESI-MS.

  1. Equilibrium unfolding of dimeric desulfoferrodoxin involves a monomeric intermediate: iron cofactors dissociate after polypeptide unfolding.


    Apiyo, D; Jones, K; Guidry, J; Wittung-Stafshede, P


    Here we report the conformational stability of homodimeric desulfoferrodoxin (dfx) from Desulfovibrio desulfuricans (ATCC 27774). The dimer is formed by two dfx monomers linked through beta-strand interactions in two domains; in addition, each monomer contains two different iron centers: one Fe-(S-Cys)(4) center and one Fe-[S-Cys+(N-His)(4)] center. The dissociation constant for dfx was determined to be 1 microM (DeltaG = 34 kJ/mol of dimer) from the concentration dependence of aromatic residue emission. Upon addition of the chemical denaturant guanidine hydrochloride (GuHCl) to dfx, a reversible fluorescence change occurred at 2-3 M GuHCl. This transition was dependent upon protein concentration, in accord with a dimer to monomer reaction [DeltaG(H(2)O) = 46 kJ/mol of dimer]. The secondary structure did not disappear, according to far-UV circular dichroism (CD), until 6 M GuHCl was added; this transition was reversible (for incubation times of < 1 h) and independent of dfx concentration [DeltaG(H(2)O) = 50 kJ/mol of monomer]. Thus, dfx equilibrium unfolding is at least three-state, involving a monomeric intermediate with native-like secondary structure. Only after complete polypeptide unfolding (and incubation times of > 1 h) did the iron centers dissociate, as monitored by disappearance of ligand-to-metal charge transfer absorption, fluorescence of an iron indicator, and reactivity of cysteines to Ellman's reagent. Iron dissociation took place over several hours and resulted in an irreversibly denatured dfx. It appears as if the presence of the iron centers, the amino acid composition, and, to a lesser extent, the dimeric structure are factors that aid in facilitating dfx's unusually high thermodynamic stability for a mesophilic protein. PMID:11305909

  2. Safety and Efficacy of PDpoetin for Management of Anemia in Patients with end Stage Renal Disease on Maintenance Hemodialysis: Results from a Phase IV Clinical Trial.


    Javidan, Abbas Norouzi; Shahbazian, Heshmatollah; Emami, Amirhossein; Yekaninejad, Mir Saeed; Emami-Razavi, Hassan; Farhadkhani, Masoumeh; Ahmadzadeh, Ahmad; Gorjipour, Fazel


    Recombinant human erythropoietin (rHuEPO) is available for correcting anemia. PDpoetin, a new brand of rHuEPO, has been certified by Food and Drug Department of Ministry of Health and Medical Education of Iran for clinical use in patients with chronic kidney disease. We conducted this post-marketing survey to further evaluate the safety and efficacy of PDpoetin for management of anemia in patients on maintenance hemodialysis. Patients from 4 centers in Iran were enrolled for this multicenter, open-label, uncontrolled phase IV clinical trial. Changes in blood chemistry, hemoglobin and hematocrit levels, renal function, and other characteristics of the patients were recorded for 4 months; 501 of the patients recruited, completed this study. Mean age of the patients was 50.9 (±16.2) years. 48.7% of patients were female. Mean of the hemoglobin value in all of the 4 centers was 9.29 (±1.43) g/dL at beginning of the study and reached 10.96 (±2.23) g/dL after 4 months and showed significant increase overall (P<0.001). PDpoetin dose was stable at 50-100 U/kg thrice weekly. Hemorheologic disturbancesand changes in blood electrolytes was not observed. No case of immunological reactions to PDpoetin was observed. Our study, therefore, showed that PDpoetin has significantly raised the level of hemoglobin in the hemodialysis patients (about 1.7±0.6 g/dL). Anemia were successfully corrected in 49% of patients under study. Use of this biosimilar was shown to be safe and effective for the maintenance of hemoglobin in patients on maintenance hemodialysis. PMID:25317316

  3. Synthesis and characterization of micrometer Cu/PVP architectures

    SciTech Connect

    Luo, Huajuan; Zhao, Yanbao; Sun, Lei


    Graphical abstract: A simple method for the synthesis of novel micrometer flower-like Cu/PVP architectures was introduced. Highlights: {yields} Micrometer flower-like copper/polyvinylpyrrolidone architectures were obtained by a simple chemical route. {yields} The amount of N{sub 2}H{sub 4}{center_dot}H{sub 2}O, the reaction temperature, the molar ratio of CuCl{sub 2} to PVP and different molecular weights of PVP play an important role in the controlling the morphology of the Cu/PVP architectures. {yields} A possible mechanism of the formation of Cu/PVP architectures was discussed. -- Abstract: Micrometer-sized flower-like Cu/polyvinylpyrrolidone (PVP) architectures are synthesized by the reduction of copper (II) salt with hydrazine hydrate in aqueous solution in the presence of PVP capping agent. The resulting Cu/PVP architectures are investigated by UV-vis spectroscopy, transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). The Cu/PVP flowers have uniform morphologies with an average diameter of 10 {mu}m, made of several intercrossing plates. The formation of Cu/PVP flowers is a new kinetic control process, and the factors such as the amount of N{sub 2}H{sub 4}{center_dot}H{sub 2}O, reaction temperature, molar ratio of CuCl{sub 2} to PVP and molecular weight of PVP have significant effect on the morphology of Cu/PVP architectures. A possible mechanism of the formation of micrometer Cu/PVP architectures was discussed.

  4. Synthesis and molecular structures of the magnesium and aluminum adducts of a niobium-oxo complex. X-ray crystal structures of [[NbOCl{sub 4}(THF)]{sub 2}Mg(THF){sub 4}] and [[NbOCl{sub 4}(THF)]{sub 2}AlCl(THF){sub 3}

    SciTech Connect

    Sobota, P.; Utko, J.; Szafert, S.


    The synthesis of high polymers based on simple Nb(V) species as catalysts has also been reported. It could be expected that V(V) and Nb(V) complexes would be effective catalysts if they could be stabilized in their high oxidation state. In this contribution, we describe the synthesis and characterization of Mg{sup 2+} and Al{sup 3+} niobium-oxo adducts. The chemistry of transition metal-oxo M=O(V, Nb, Ta) adducts with electropositive metal ions such as Mg{sup 2+} or Al{sup 3+} as components of the catalyst is unknown yet. In a previous paper we described the synthesis and properties of products formed during reaction between [MoOCl{sub 3}(THF){sub 2}] and [MgCl{sub 2}(THF){sub 2}]. As an extension of these studies, we chose to investigate the chemistry of niobium-oxo species [NbOCl{sub 4}(THF)]{sup -} with MgCl{sub 2} and AlCl{sub 3} in order to compare the basic properties of Nb=O with M=O (M = Mo, W, Re) moieties. In this paper we describe the synthesis of [[NbOCl{sub 4}(THF)]{sub 2}Mg(THF){sub 4}]{center_dot}CH{sub 2-}Cl{sub 2}, [[NbOCl{sub 4}(THF)]{sub 2}Mg(THF){sub 4}]{center_dot}4THF And [[NbOCl{sub 4}(THF)]{sub 2-} AlCl(THF){sub 3}] species and report the details of their x-ray structures.

  5. Erectile Dysfunction in Individuals with Neurologic Disability: A Hospital-based Cross-sectional Study

    PubMed Central

    Gervasi, Giuseppe; Naro, Antonino; de Luca, Rosaria; Marullo, Michelangelo; Bramanti, Placido


    Objective: Neurogenic erectile dysfunction can be broadly defined as an inability to sustain or maintain a penile erection due to neurologic impairment. Sexual problems can occur due to any lesion affecting the central and peripheral nervous system. The aim of this study was to evaluate the prevalence and causes of erectile dysfunction in a group of hospital inpatients suffering from neurologic disorders. Methods: Three-hundred and twenty six male patients admitted to the Neurorehabilitation Unit of IRCCS Centro Neurolesi “Bonino-Pulejo” in Messina Italy from March 2012 to June 2013 were screened for erectile dysfunction using the International Index of Erectile Function questionnaire. The patients who reported erectile dysfuntion underwent vascular, neurophysiological, and hormonal testing, and were divided into two groups according to their lesion sites: G1 (lesions above the S2-S4 center) and G2 (lesions below the S2-S4 center). Results: Of the 326 admitted patients, 126 patients (38.6%), mean age of 54.56±11.74 years (age range 27-82 years), were affected by erectile dysfunction (i.e., scored ≤21). A statistically significant correlation between International Index of Erectile Function questionnaire scores and location of the neurologic lesions was observed in G2 (r=0.22) with an increased risk of erectile dysfuntion of around 2:1 (odds ratio=1.87) without influences related to aging. Conclusion: The occurence of erectile dysfunction is significantly more prevalent among neurologically disabled men, particularly those with lesions below S2-S4, than among men without neurologic disability. Considering the prevalence of erectile dysfunction among neurologically disabled men, sexual functioning should be regularly evaluated during acute and long-term rehabilitation, and any existing sexual dysfunction should be addressed in the treatment plan. PMID:27413582

  6. Safety and Efficacy of PDpoetin for Management of Anemia in Patients with end Stage Renal Disease on Maintenance Hemodialysis: Results from a Phase IV Clinical Trial

    PubMed Central

    Javidan, Abbas Norouzi; Shahbazian, Heshmatollah; Emami, Amirhossein; Yekaninejad, Mir Saeed; Emami-Razavi, Hassan; Farhadkhani, Masoumeh; Gorjipour, Fazel


    Recombinant human erythropoietin (rHuEPO) is available for correcting anemia. PDpoetin, a new brand of rHuEPO, has been certified by Food and Drug Department of Ministry of Health and Medical Education of Iran for clinical use in patients with chronic kidney disease. We conducted this post-marketing survey to further evaluate the safety and efficacy of PDpoetin for management of anemia in patients on maintenance hemodialysis. Patients from 4 centers in Iran were enrolled for this multicenter, open-label, uncontrolled phase IV clinical trial. Changes in blood chemistry, hemoglobin and hematocrit levels, renal function, and other characteristics of the patients were recorded for 4 months; 501 of the patients recruited, completed this study. Mean age of the patients was 50.9 (±16.2) years. 48.7% of patients were female. Mean of the hemoglobin value in all of the 4 centers was 9.29 (±1.43) g/dL at beginning of the study and reached 10.96 (±2.23) g/dL after 4 months and showed significant increase overall (P<0.001). PDpoetin dose was stable at 50-100 U/kg thrice weekly. Hemorheologic disturbancesand changes in blood electrolytes was not observed. No case of immunological reactions to PDpoetin was observed. Our study, therefore, showed that PDpoetin has significantly raised the level of hemoglobin in the hemodialysis patients (about 1.7±0.6 g/dL). Anemia were successfully corrected in 49% of patients under study. Use of this biosimilar was shown to be safe and effective for the maintenance of hemoglobin in patients on maintenance hemodialysis. PMID:25317316

  7. Novel alkaline earth copper germanates with ferro and antiferromagnetic S=1/2 chains

    SciTech Connect

    Brandao, Paula; Reis, Mario S.; Santos, Antonio M. dos


    Two new alkaline earth copper(II) germanates were hydrothermally synthesized: CaCuGeO{sub 4}{center_dot}H{sub 2}O (1) and BaCu{sub 2}Ge{sub 3}O{sub 9}{center_dot}H{sub 2}O (2), and their structures determined by single crystal X-ray diffraction. Compound (1) crystallizes in space group P2{sub 1}/c with a=5.1320(2) Angstrom-Sign , b=16.1637(5) Angstrom-Sign , c=5.4818(2) Angstrom-Sign , {beta}=102.609(2) Degree-Sign , V=443.76(3) Angstrom-Sign {sup 3} and Z=4. This copper germanate contains layers of composition [CuGeO{sub 4}]{sub {infinity}}{sup 2-} comprising CuO{sub 4} square planes and GeO{sub 4} tetrahedra with calcium and water molecules in the inter-layer space. Compound (2) crystallizes in the Cmcm space group with a=5.5593(3) Angstrom-Sign , b=10.8606(9) Angstrom-Sign , c=13.5409(8) Angstrom-Sign , V=817.56(9) Angstrom-Sign {sup 3} and Z=4. This structure contains GeO{sub 6} and CuO{sub 6} octahedra as well as GeO{sub 4} tetrahedra, forming a three-dimensional network of interconnecting six-membered ring channels. The magnetic susceptibility for both samples can be interpreted as S=1/2 chains, in agreement with the copper topology observed in the crystal structure. The susceptibility of (1) exhibits a Bonner-Fisher type behavior, resulting from antiferromagnetic intra-chain interactions without three-dimensional ordering down to 5 K-the lowest measured temperature. This observation, together with the absence of super-exchange paths between the copper chains, make this system particularly promising for the study of low dimensional magnetism. The magnetic properties of (2) show a very weak ferromagnetic near-neighbor interaction along the chain. In this compound a peak the {chi}T plot seems to indicate the onset of interchain antiferromagentic correlations. However, no ordering temperature is detected in the susceptibility data. - Graphical abstract: Copper chains present in CaCuGeO{sub 4}{center_dot}H{sub 2}O and BaCu{sub 2}Ge{sub 3}O{sub 9}{center


    SciTech Connect

    Kevin C. Galbreath; Richard L. Schulz; Donald L. Toman; Carolyn M. Nyberg


    Representative duplicate fly ash samples were obtained from the stacks of 400-MW and 385-MW utility boilers (Unit A and Unit B, respectively) using a modified U.S. Environmental Protection Agency (EPA) Method 17 sampling train assembly as they burned .0.9 and 0.3 wt% S residual oils, respectively, during routine power plant operations. Residual oil fly ash (ROFA) samples were analyzed for nickel (Ni) concentrations and speciation using inductively coupled plasma-atomic emission spectroscopy, x-ray absorption fine structure (XAFS) spectroscopy, x-ray diffraction (XRD), and a water-soluble Ni extraction method. ROFA water extraction residues were also analyzed for Ni speciation using XAFS and XRD. Total Ni concentrations in the ROFAs were similar, ranging from 1.3 to 1.5 wt%; however, stack gas Ni concentrations in the Unit A were {approx}990 {micro}g/Nm{sup 3} compared to {approx}620 {micro}g/Nm{sup 3} for Unit B because of the greater residual oil feed rates employed at Unit A to attain higher load (i.e., MW) conditions with a lower heating value oil. Ni speciation analysis results indicate that ROFAs from Unit A contain about 3 wt% NiSO{sub 4} {center_dot} xH{sub 2}O (where x is assumed to be 6 for calculation purposes) and a Ni-containing spinel compound, similar in composition to (Mg,Ni)(Al,Fe){sub 2}O{sub 4}. ROFAs from Unit B contain on average 2.0 wt% NiSO{sub 4} {center_dot} 6H{sub 2}O and 1.1 wt% NiO. XAFS and XRD analyses did not detect any nickel sulfide compounds, including nickel subsulfide (Ni{sub 3}S{sub 2}) (XAFS detection limit is 5% of the total Ni concentration). In addition, XAFS measurements indicated that inorganic sulfate and organic thiophene species account for >97% of the total sulfur in the ROFAs. The presence of NiSO{sub 4} {center_dot} xH{sub 2}O and nickel oxide compound mixtures and lack of carcinogenic Ni{sub 3}S{sub 2} or nickel sulfide compounds (e.g., NiS, NiS{sub 2}) in ROFAs stack-sampled from 400- and 385-MW boilers are contrary

  9. CoTiO{sub 3} via cobalt oxalate-TiO{sub 2} precursor. Synthesis and characterization

    SciTech Connect

    Gabal, M.A. Hameed, S.A.; Obaid, A.Y.


    Purely trigonal ilmenite type powder; CoTiO{sub 3} was successfully synthesized through the thermal decomposition of CoC{sub 2}O{sub 4}{center_dot}2H{sub 2}O-TiO{sub 2} precursor. The decomposition course was followed using differential thermal analysis-thermogravimetry measurements and the intermediate decomposition products as well as the titanate product were characterized using X-ray diffraction, Fourier transform infrared, transmission electron microscopy techniques. Thermal analysis study indicated that, the intermediate decomposition product; Co{sub 3}O{sub 4} decomposed endothermically into CoO at 963 Degree-Sign C with instantaneous formation of CoTiO{sub 3}. X-ray diffraction of the powder calcined at 950 Degree-Sign C showed characteristic lines for Co{sub 2}TiO{sub 4} besides secondary phase of rutile-TiO{sub 2}, which are disappeared by rising the calcination temperature to 1000 Degree-Sign C. Transmission electron microscopy image of CoTiO{sub 3} powder exhibit weak agglomerated particles with heterogeneous morphology in both shape and dimensions. Type II adsorption isotherm estimated using Brunauer-Emmett-Teller procedure indicated a very high specific surface area of 29.7 m{sup 2} g{sup -1}. Electrical properties of CoTiO{sub 3} measured as a function of temperature and frequency showed a semiconducting behavior at high temperatures with conduction activation energy of 0.73 eV. Kinetic analysis of the non-isothermal thermogravimetry curves, using different computational methods, illustrated that the random nucleation and growth mechanisms are the predominant one. - Graphical Abstract: The figure showed the variation of dielectric constant ({epsilon} Prime ) for CoTiO{sub 3} with temperature at different frequencies. {epsilon} Prime appeared to be temperature and frequency independent at low temperatures. By increasing the temperature, the orientation polarization plays a significant role and a gradual increase of {epsilon} Prime occurred. Highlights

  10. Synthesis, characterization, and intercalation of vanadyl phsophate modified with manganese

    SciTech Connect

    Richtrova, K.; Votinsky, J.; Kalousova, J.


    A yellow-brown crystalline solid, stable in air and having a variable composition of [Mn(H{sub 2}O)]{sub x}(VO){sub 1-x}PO{sub 4}{center_dot}2H{sub 2}O (0 {le} x {le} 0.25), has been prepared by the reaction of solid V{sub 2}O{sub 5} with a boiling aqueous solution of H{sub 3}PO{sub 4} and KMnO{sub 4}. The elementary cell of this compound is tetragonal (space symmetry group either P4/n or P4/nmm) with the following parameters for x = 0.25; a = 0.62034 nm, c = 1.3813 nm, V = 0.51359 nm{sup 3}, Z = 4, M{sub r} = 199.44, D{sub calc} = 2.492 g/cm{sup 3}, and D{sub exp} = 2.52 g/cm{sup 3}. The magnetic behavior of this substance indicates the presence of manganese atoms at the oxidation level of III. The paramagnetic centers formed by the Mn{sub III} atoms are not markedly magnetically coupled. The structure of the compound is probably derived from the original layered lattice of vanadyl phosphate hydrate VOPO{sub 4}{center_dot}2H{sub 2}O by replacement of at most one quarter of the vanadyl groups (V{sup V}O){sup 3+} by [Mn{sup III}(H{sub 2}O)]{sup 3+} groups. Upon being heated, the substance forms a monohydrate at first, then the anhydrous salt forms, and finally the water coordinated with manganese atoms escapes. The compound can be intercalated with foreign molecules and ions in the same way as vanadyl phosphate, and the results of intercalation experiments with methanol, ethanol, 1-propanol, 1-butanol, 1-butylamine, 1-octylamine, formic acid, acetic acid, and pyridine, as well as those of oxidation-reduction intercalation with a solution of sodium intercalations are described. The layered complexes formed have been identified by powder X-ray structure analysis, thermogravimetry, differential thermal analysis, and infrared absorption spectroscopy.

  11. Inhibited Release of Mobile Contaminants from Hanford Tank Residual Waste

    SciTech Connect

    Cantrell, Kirk J.; Heald, Steve M.; Arey, Bruce W.; Lindberg, Michael J.


    Investigations of contaminant release from Hanford Site tank residual waste have indicated that in some cases certain contaminants of interest (Tc and Cr) exhibit inhibited release. The percentage of Tc that dissolved from residual waste from tanks 241-C-103, 241-C-106, 241-C-202, and 241-C-203 ranged from approximately 6% to 10%. The percent leachable Cr from residual waste from tanks C-103, C 202, and C-203 ranged from approximately 1.1% to 44%. Solid phase characterization results indicate that the recalcitrant forms of these contaminants are associated with iron oxides. X-ray absorption near edge structure analysis of Tc and Cr in residual waste indicates that these contaminants occur in Fe oxide particles as their lower, less soluble oxidation states [Tc(IV) and Cr(III)]. The form of these contaminants is likely as oxides or hydroxides incorporated within the structure of the Fe oxide. Leaching behavior of U from tank residual waste was studied using deionized water, and CaCO3 and Ca(OH)2 saturated solutions as leachants. The release behavior of U from tank residual waste is complex. Initial U concentrations in water and CaCO3 leachants are high due to residual amounts of the highly soluble U mineral cejkaite. As leaching and dilution occur NaUO2PO4 {center_dot} xH2O, Na2U2O7(am) and schoepite (or a similar phase) become the solubility controlling phases for U. In the case of the Ca(OH)2 leachant, U release from tank residual waste is dramatically reduced. Thermodynamic modeling indicates that the solubility of CaUO4(c) controls release of U from residual waste in the Ca(OH)2 leachants. It is assumed the solubility controlling phase is actually a hydrated version of CaUO4 with a variable water content ranging from CaUO4 to CaUO4 {center_dot} (H2O). The critically reviewed value for CaUO4(c) (log KSP0 = 15.94) produced good agreement with our experimental data for the Ca(OH)2 leachates.

  12. Crystal structures, fluorescent and magnetic properties of five new coordination polymers based on biphenyl-3,4 Prime ,5-tricarboxylic acid

    SciTech Connect

    Lu Yingli; Zhao Wenjie; Liu Yu; Liu Bin; Feng Xing; Tan Jinting; Li Xia; Yang Xuwu


    Five new coordination polymers, {l_brace}[Cd{sub 3}(bpt){sub 2}(DMF){sub 2}]{center_dot}(H{sub 2}O){sub 2}{r_brace}{sub n} (1), [Cd(Hbpt)(bipy){sub 0.5}(H{sub 2}O)]{sub n} (2), [Cd{sub 2}(bpt)(phen){sub 2}Cl]{sub n} (3), {l_brace}[Cu{sub 2}(bpt)(phen)({mu}{sub 2}-OH)(H{sub 2}O)]{center_dot}(H{sub 2}O){sub 2}{r_brace}{sub n} (4) and {l_brace}[Mn{sub 5}(Hbpt){sub 4}(phen){sub 4}({mu}{sub 2}-OH){sub 2}(H{sub 2}O){sub 2}]{center_dot}(H{sub 2}O){sub 2}(CH{sub 3}CN){sub 2}{r_brace}{sub n} (5) have been prepared through hydro(solvo)thermal reactions of H{sub 3}bpt (H{sub 3}bpt=biphenyl-3,4 Prime ,5-tricarboxylic acid) with different pyridyl-containing auxiliary ligands (bipy=4,4 Prime -bipyridine and phen=1,10-phenanthroline). Compound 1 represents a 3D ladder-like framework composed of rod-shaped infinite chains. In 2, the bridging ligand bipy links binuclear cadmium ions to generate a 2D layer. Compound 3 features a 1D ladder structure and further linked by {pi}-{pi} stacking interaction to form a 3D supramolecular network. Compound 4 exhibits a binodal 3-connected net which features the Schlafli symbol of (4{center_dot}8{sup 2}). Compound 5 contains trimetallic cluster and binuclear unite which are further linked by Hbpt ligand to form a 2D layer. Moreover, photoluminescent properties of compounds 1-3 were studied in the solid state. Magnetic susceptibility measurements indicate that compound 4 exhibits ferromagnetic exchange interactions, whereas compound 5 displays antiferromagnetic exchange interactions. - Graphical abstract: Five new coordination polymers have been prepared through reactions of H{sub 3}bpt with different pyridyl-containing auxiliary ligands. The bpt exhibits four new kinds of coordination modes with 'V or Y shape'. Highlights: Black-Right-Pointing-Pointer 1 represents a unique (4{center_dot}8)-connected network with a Schlafli symbol (4{sup 6})(4{sup 12}{center_dot}6{sup 12}{center_dot}8{sup 4}). Black-Right-Pointing-Pointer Compound 4 shows

  13. Improvement of discharge characteristics of latent heat thermal energy storage unit by using carbon fibers

    SciTech Connect

    Fukai, Jun; Oishi, Akira; Kodama, Yoshikazu; Kanou, Makoto; Miyatake, Osamu


    Many phase change materials have unacceptably low thermal conductivities. Metal fins, metal honeycombs and metal matrices have been examined to enhance the thermal conductivity of the PCMs. This study proposed an enhancement technique using carbon fibers with high thermal conductivity. The thermal conductivity of the carbon fibers prepared in this study is 220 W/(m{center_dot}K). Paraffin wax (0.26 W/(m{center_dot}K) in solid phase) and Na{sub 2}SO{sub 4}{center_dot}10H{sub 2}O-mixture (0.8 W/(m{center_dot}K) in solid phase) were selected as heat storage media. The fibers were uniformly mixed with th PCM encapsulated in a cylindrical capsule. The effective thermal conductivities of the fibers/PCM composites were measured. Figure A-1 shows the ratio of the effective thermal conductivity of the composite (k{sub c}) to the thermal conductivity of the phase change material (k{sub m}). The figure demonstrates that the fibers essentially enhance the thermal conductivities of paraffin. For paraffin, there is little dependence of the effective thermal conductivity on the fiber length (L{sub f}). Though the k{sub c}/k{sub m} for Na{sub 2}SO{sub 4}{center_dot}10H{sub 2}O-mixture is lower than that of the paraffin wax, 2% fibers increase the thermal conductivity of the PCM by a factor of about three. This value is almost identical to the thermal conductivity of ice (2.2 W/(m{center_dot}K)). The effect of the carbon fibers on discharge characteristics of a thermal energy storage system was investigated. Capsules containing a carbon fibers/paraffin composite are packed into a thermal energy storage unit. The inlet fluid temperature (T{sub in})and the outlet fluid temperature (T{sub out}) were measured during the discharge process. Figure A-2 shows a typical result of the experiments. Remarkable effect of the fibers is observed after the outlet temperature reaches the phase change temperature ({approx}60 C). That is, the period where the outlet temperature is maintained near the

  14. Drying results of K-Basin fuel element 3128W (run 2)

    SciTech Connect

    Abrefah, J.; Klinger, G.S.; Oliver, B.M.; Marshman, S.C.; MacFarlan, P.J.; Ritter, G.A.; Flament, T.A.


    An N-Reactor outer fuel element that had been stored underwater in the Hanford 100 Area K-East Basin was subjected to a combination of low- and high-temperature vacuum drying treatments. These studies are part of a series of tests being conducted by Pacific Northwest National Laboratory on the drying behavior of N-Reactor spent nuclear fuel elements removed from both the K-West and K-East Basins. The drying test series was designed to test fuel elements that ranged from intact to severely damaged. The fuel element discussed in this report was removed from an open K-East canister (3128W) during the first fuel selection campaign conducted in 1995, and has remained in wet storage in the Postirradiation Testing Laboratory (PTL, 327 Building) since that time. Although it was judged to be breached during in-basin (i.e., K-Basin) examinations, visual inspection of this fuel element in the hot cell indicated that it was likely intact. Some scratches on the coating covering the cladding were identified before the furnace test. The drying test was conducted in the Whole Element Furnace Testing System located in G-Cell within the PTL. This test system is composed of three basic systems: the in-cell furnace equipment, the system gas loop, and the analytical instrument package. Element 3128W was subjected to the drying processes based on those proposed under the Integrated Process Strategy, which included a hot drying step. Results of the Pressure Rise and Gas Evolution Tests suggest that most of the free water in the system was released during the extended CVD cycle (68 hr versus 8 hr for the first run). An additional {approximately}0.34 g of water was released during the subsequent HVD phase, characterized by multiple water release peaks, with a principle peak at {approximately}180 C. This additional water is attributed to decomposition of a uranium hydrate (UO{sub 4}{center_dot}4H{sub 2}O/UO{sub 4}{center_dot}2H{sub 2}O) coating that was observed to be covering the surface

  15. Synthesis, crystal structures and properties of lanthanide-organic frameworks based benzene carboxylates with two/three-dimensional structure

    SciTech Connect

    Wang, Ping; Fan, Ruiqing; Yang, Yulin; Liu, Xinrong; Cao, Wenwu; Yang, Bin


    A series of lanthanide coordination polymers, {l_brace}[Dy{sub 3}(1,3-BDC){sub 4}(NO{sub 3})(phen){sub 3}]{center_dot}2H{sub 2}O{r_brace}{sub n} (1), {l_brace}[Dy{sub 2}(1,3-BDC){sub 3}(H{sub 2}O){sub 2}]{center_dot}H{sub 2}O{r_brace}{sub n} (2), {l_brace}[Ln{sub 4}(1,3-BDC){sub 6}(DMF)(H{sub 2}O){sub 4}]{center_dot}DMF{center_dot}2H{sub 2}O{r_brace}{sub n} (Ln=Tb (3), Ho (4), Er (5), 1,3-H{sub 2}BDC=1,3-benzenedicarboxylate, phen=1,10-phenanthroline, DMF=N,N-dimethylformamide), have been synthesized and characterized. In coordination polymer 1, each Dy{sup 3+} ion is connected to its neighboring Dy{sup 3+} ion through bridging carboxyl oxygen atoms of the 1,3-BDC{sup 2-} ligands to form a new three-dimensional open-framework structure which the Schlaefli symbol of {l_brace}6{sup 4}{center_dot}8{sup 2}{r_brace}{sub 2}{l_brace}6{sup 6}{r_brace}. In coordination polymer 2, center metal dysprosium ions are interlaced and connected through bridging carboxyl oxygen atoms to form an infinite helix chain. Two helix chains are linked through the 1,3-BDC{sup 2-} ligand to give rise to the two-dimensional layered structure. Coordination polymers 3-5 are isomorphous, which displays a (3,4)-connected net with the point symbol of {l_brace}4{sup 2}{center_dot}6{sup 3}{center_dot}8{r_brace}{l_brace}4{sup 2}{center_dot}6{r_brace}. The solid-state photoluminescence properties and lifetimes of the Dy (1 and 2) and Tb (3) coordination polymers have been measured at room temperature. Highlights: Black-Right-Pointing-Pointer Five lanthanide coordination polymers based on 1,3-H{sub 2}BDC were obtained. Black-Right-Pointing-Pointer The polymers were structurally characterized by single-crystal X-ray diffraction. Black-Right-Pointing-Pointer Coordination polymers 1-5 display different topological structures. Black-Right-Pointing-Pointer They show characteristic emissions of lanthanide ions in the solid state.

  16. Synthesis and Coordination Chemistry of Phosphine Oxide Decorated Dibenzofuran Platforms

    SciTech Connect

    Rosario-Amorin, Daniel; Duesler, Eileen N.; Paine, Robert T.; Hay, Benjamin; Delmau, Laetitia Helene; Reilly, Sean D.; Gaunt, Andrew J.; Scott, Brian L.


    A four-step synthesis for 4,6-bis(diphenylphosphinoylmethyl)dibenzofuran (4) from dibenzofuran and a two-step synthesis for 4,6-bis(diphenylphosphinoyl)dibenzofuran (5) are reported along with coordination chemistry of 4 with In(III), La(III), Pr(III), Nd(III), Er(III), and Pu(IV) and of 5 with Er(III). Crystal structure determinations for the ligands, 4 {center_dot} CH{sub 3}OH and 5, the 1:1 complexes [In(4)(NO{sub 3}){sub 3}], [Pr(4)(NO{sub 3}){sub 3}(CH{sub 3}CN)] {center_dot} 0.5CH{sub 3}CN, [Er(4)(NO{sub 3}){sub 3}(CH{sub 3}CN)] {center_dot} CH{sub 3}CN, [Pu(4)Cl4] {center_dot} THF and the 2:1 complex [Nd(4){sub 2}(NO{sub 3}){sub 2}]{sub 2}(NO{sub 3}){sub 2} {center_dot} (H{sub 2}O) {center_dot} 4(CH{sub 3}OH) are described. In these complexes, ligand 4 coordinates in a bidentate POP{prime}O{prime} mode via the two phosphine oxide O-atoms. The dibenzofuran ring O-atom points toward the central metal cations, but in every case it is more than 4 {angstrom} from the metal. A similar bidentate POP{prime}O{prime} chelate structure is formed between 5 and Er(III) in the complex, {l_brace}[Er(5){sub 2}(NO{sub 3}){sub 2}](NO{sub 3}) {center_dot} 4(CH{sub 3}OH){r_brace}0.5, although the nonbonded Er{hor_ellipsis} O{sub furan} distance is reduced to 3.6 {angstrom}. The observed bidentate chelation modes for 4 and 5 are consistent with results from molecular mechanics computations. The solvent extraction performance of 4 and 5 in 1,2-dichloroethane for Eu(III) and Am(III) in nitric acid solutions is described and compared against the extraction behavior of n-octyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide (O{Phi}DiBCMPO) measured under identical conditions.

  17. Thermally stable carbon-related centers in 6H-SiC: Photoluminescence spectra and microscopic models

    SciTech Connect

    Mattausch, Alexander; Bockstedte, Michel; Pankratov, Oleg; Steeds, John W.; Furkert, Suzanne; Hayes, Jonathan M.; Sullivan, Wayne; Wright, Nick G.


    Recent ab initio calculations [Mattausch et al., Phys. Rev. B 70, 235211 (2004)] of carbon clusters in SiC reveal a possible connection between the tricarbon antisite (C{sub 3}){sub Si} and the U photoluminescence center in 6H-SiC [Evans et al., Phys. Rev. B 66, 35204 (2002)]. Yet, some of the predicted vibrational modes were not observed experimentally. We report experiments that, indeed, confirm the existence of a low-energy mode for the U center (as well as for the HT3 and HT4 centers with spectral details similar to the U center). We calculated the isotope splitting for the (C{sub 3}){sub Si}-defect and found near-perfect agreement with our data. In addition, we discuss the carbon di-interstitial (C{sub 2}){sub Hex} as a model for the Z and HT5 centers. The isotope splitting is also well reproduced, but the absolute values of the local mode energies show a discrepancy of about 10 meV.

  18. Uptake of chloride and carbonate ions by calcium monosulfoaluminate hydrate

    SciTech Connect

    Mesbah, Adel; Cau-dit-Coumes, Celine; Frizon, Fabien


    Decommissioning of old nuclear reactors may produce waste streams containing chlorides and carbonates, including radioactive {sup 36}Cl{sup -} and {sup 14}CO{sub 3}{sup 2-}. Their insolubilization by calcium monosulfoaluminate hydrate was investigated. Carbonates were readily depleted from the solution, giving at thermodynamic equilibrium monocarboaluminate, monocarboaluminate + calcite, or calcite only, depending on the initial ratio between the anion and calcium monosulfoaluminate hydrate. Chloride ions reacted more slowly and were precipitated as Kuzel's salt, Kuzel's and Friedel's salts, or Friedel's salt only. Rietveld refinement of X-Ray powder diffraction patterns was successfully used to quantify the phase distributions, which were compared to thermodynamic calculations. Moreover, analysing the lattice parameters of Kuzel's salt as a function of its chloride content showed the occurrence of a restricted solid solution towards the sulfate side with general formula 3CaO{center_dot}Al{sub 2}O{sub 3}{center_dot}xCaCl{sub 2}{center_dot}(1 - x)CaSO{sub 4}{center_dot}(12 - 2x){center_dot}H{sub 2}O (0.36 {<=} x {<=} 0.50).

  19. Extraction of phenol using sulfuric acid salts of trioctylamine in a supported liquid membrane

    SciTech Connect

    Wang, M.L.; Hu, K.H. )


    The extraction of phenol by trioctylamine sulfate salts in a supported-liquid membrane (SLM) process was investigated. In the extraction process, a transport model, which included the film diffusion of phenol in the aqueous phase, the membrane diffusion within the SLM, and the interfacial chemical reaction, was built. The experimental parameters, such as the cell constant ([beta]), the diffusivity of (TOA)[sub 2]H[sub 2]SO[sub 4][center dot]PhOH in the SLM (D[sub c,b]), and the mass-transfer coefficient of phenol in the aqueous solution (K[sub L]), were determined from experiments. On the basis of the experimental data and the results obtained from the transport model, the rate-controlling step of the extraction of phenol by an SLM during permeation is discussed. The effects of the operating variables and parameters, such as the initial concentration of phenol in the aqueous phase, sulfuric acid, sodium hydroxide, and trioctylamine sulfate salts, on the extraction of phenol were examined.

  20. Accuracy of navigation-assisted acetabular component positioning studied by computed tomography measurements: methods and results.


    Ybinger, Thomas; Kumpan, W; Hoffart, H E; Muschalik, B; Bullmann, W; Zweymüller, K


    The postoperative position of the acetabular component is key for the outcome of total hip arthroplasty. Various aids have been developed to support the surgeon during implant placement. In a prospective study involving 4 centers, the computer-recorded cup alignment of 37 hip systems at the end of navigation-assisted surgery was compared with the cup angles measured on postoperative computerized tomograms. This comparison showed an average difference of 3.5 degrees (SD, 4.4 degrees ) for inclination and 6.5 degrees (SD, 7.3 degrees ) for anteversion angles. The differences in inclination correlated with the thickness of the soft tissue overlying the anterior superior iliac spine (r = 0.44; P = .007), whereas the differences in anteversion showed a correlation with the thickness of the soft tissue overlying the pubic tubercles (r = 0.52; P = .001). In centers experienced in the use of navigational tools, deviations were smaller than in units with little experience in their use. PMID:17826270

  1. Resonant planar antenna as an inductive plasma source

    SciTech Connect

    Guittienne, Ph.; Lecoultre, S.; Howling, A. A.; Hollenstein, Ch.; Fayet, P.; Larrieu, J.


    A resonant planar antenna as an inductive plasma source operating at 13.56 MHz inside a low pressure vacuum vessel is presented for potential plasma processing applications. Its principle consists in interconnecting elementary resonant meshes composed of inductive and capacitive elements. Due to its structure, the antenna shows a set of resonant modes associated with peaks of the real input impedance. Each of these modes is defined by its own current and voltage distribution oscillating at the frequency of the mode. A rectangular antenna of 0.55mx0.20m has been built, and first results obtained with argon plasmas are presented. Plasma generation is shown to be efficient as densities up to 4{center_dot}10{sup 17}m{sup -3} at 2000 W have been measured by microwave interferometry at a distance of 4 cm from the source plane. It is also demonstrated that the plasma couples inductively with the resonating currents flowing in the antenna above a threshold power of about 60 W. A non-uniformity of less than {+-}5% is obtained at 1000 W at a few centimeters above the antenna over 75% of its surface.

  2. Photochemical reaction of sulfur hexafluoride with water in low-temperature xenon matrices

    SciTech Connect

    Yamada, Yasuhiro; Tamura, Hiroyuki; Takeda, Daisuke


    Sulfur hexafluoride SF{sub 6} is a very stable molecule with which very few reactions with other molecules have been reported. Here, we report a photochemical reaction of SF{sub 6} with water molecules using a matrix-isolation technique, where SF{sub 6} and H{sub 2}O were co-condensed in Xe matrices, and the products were observed using infrared spectroscopy. Irradiation at 193 nm from an ArF excimer laser caused the simultaneous decomposition of SF{sub 6} and H{sub 2}O, which resulted in the production of novel species. Infrared spectra and molecular orbital calculations of the species showed that the product was a SF{sub 4}{center_dot}{center_dot}{center_dot}HF{center_dot}{center_dot}{center_dot}HOF complex, which consists of hydrogen bonds and charge transfer interaction between S and F atoms. The assignment of the species was confirmed by isotope shifts using D and {sup 18}O isotope substitutions.

  3. CHD7 Gene Polymorphisms Are Associated with Susceptibility to Idiopathic Scoliosis

    PubMed Central

    Gao, Xiaochong; Gordon, Derek; Zhang, Dongping; Browne, Richard; Helms, Cynthia; Gillum, Joseph; Weber, Samuel; Devroy, Shonn; Swaney, Saralove; Dobbs, Matthew; Morcuende, Jose; Sheffield, Val; Lovett, Michael; Bowcock, Anne; Herring, John; Wise, Carol


    Idiopathic scoliosis (IS) is the most common spinal deformity in children, and its etiology is unknown. To refine the search for genes underlying IS susceptibility, we ascertained a new cohort of 52 families and conducted a follow-up study of genomewide scans that produced evidence of linkage and association with 8q12 loci (multipoint LOD 2.77; P=.0028). Further fine mapping in the region revealed significant evidence of disease-associated haplotypes (P<1.0×10-4) centering over exons 2–4 of the CHD7 gene associated with the CHARGE (coloboma of the eye, heart defects, atresia of the choanae, retardation of growth and/or development, genital and/or urinary abnormalities, and ear abnormalities and deafness) syndrome of multiple developmental anomalies. Resequencing CHD7 exons and conserved intronic sequence blocks excluded coding changes but revealed at least one potentially functional polymorphism that is overtransmitted (P=.005) to affected offspring and predicts disruption of a caudal-type (cdx) transcription-factor binding site. Our results identify the first gene associated with IS susceptibility and suggest etiological overlap between the rare, early-onset CHARGE syndrome and common, later-onset IS. PMID:17436250

  4. Hydrothermal Transformation of the Calcium Aluminum Oxide Hydrates CaAl2O4 . 10H2O and Ca2Al2O. 8H2O to Ca3Al2(OH)12 Investigated by In Situ Synchrotron X-ray Powder Diffraction

    SciTech Connect

    Jensen,T.; Christensen, A.; Hanson, J.


    The hydrothermal transformation of calcium aluminate hydrates were investigated by in situ synchrotron X-ray powder diffraction in the temperature range 25 to 170 C. This technique allowed the study of the detailed reaction mechanism and identification of intermediate phases. The material CaAl{sub 2}O{sub 4}{center_dot}10H{sub 2}O converted to Ca{sub 3}Al{sub 2}(OH){sub 12} and amorphous aluminum hydroxide. Ca{sub 2}Al{sub 2}O{sub 5}{center_dot}8H{sub 2}O transformed via the intermediate phase Ca{sub 4}Al{sub 2}O{sub 7}{center_dot}13H{sub 2}O to Ca{sub 3}Al{sub 2}(OH){sub 12} and gibbsite, Al(OH){sub 3}. The phase Ca{sub 4}Al{sub 2}O{sub 7}{center_dot}19H{sub 2}O reacted via the same intermediate phase to Ca{sub 3}Al{sub 2}(OH){sub 12} and mainly amorphous aluminum hydroxide. The powder pattern of the intermediate phase is reported.

  5. Characterization of the iron-sulfur centers in succinate dehydrogenase.

    PubMed Central

    Coles, C J; Holm, R H; Kurtz, D M; Orme-Johnson, W H; Rawlings, J; Singer, T P; Wong, G B


    Two techniques have been applied to the determination of the number and type (2-Fe, 4-Fe) of iron-sulfur centers in the iron-sulfur flavoprotein succinate dehydrogenase [succinate:(acceptor) oxidoreductase, EC]. One procedure uses p-CF3C6H4SH as an extrusion reagent and Fourier transform 19F nuclear magentic resonance as the method of detection and quantitation of extruded cores of these centers in the form of [Fe2S2(SRF)4]2- and [Fe4S4(SRF)4]2- (RF = p-C6H4CF3). The second procedure, interprotein core transfer, involves thiol displacement of iron-sulfur cores followed by specific core transfer to the apoproteins of Bacillus polymyxa ferredoxin and adrenodoxin. Detection and quantitation are accomplished by electron paramagnetic resonance of reduced proteins at low temperatures. Both procedures clearly show that succinate dehydrogenase contains two dimeric (Fe2S2) and one tetrameric (Fe4S4) centers per mole of histidyl flavin, accounting for all eight nonheme iron and eight labile sulfur atoms found by chemical analysis. These results remove uncertainties created by the less than stoichiometric amounts of binuclear centers detected by electron paramagnetic resonance after dithionite reduction and provide secure characterization of the iron-sulfur centers in this enzyme. PMID:226982


    SciTech Connect

    Michael W. Grutzeck; Maria DiCola; Paul Brenner


    Flue gas desulphurization (FGD) materials are produced in abundant quantities by coal burning utilities. Due to environmental restrains, flue gases must be ''cleaned'' prior to release to the atmosphere. They are two general methods to ''scrub'' flue gas: wet and dry. The choice of scrubbing material is often defined by the type of coal being burned, i.e. its composition. Scrubbing is traditionally carried out using a slurry of calcium containing material (slaked lime or calcium carbonate) that is made to contact exiting flue gas as either a spay injected into the gas or in a bubble tower. The calcium combined with the SO{sub 2} in the gas to form insoluble precipitates. Some plants have been using dry injection of these same materials or their own Class C fly ash to scrub. In either case the end product contains primarily hannebachite (CaSO{sub 3} {center_dot} 1/2H{sub 2}O) with smaller amounts of gypsum (CaSO{sub 4} {center_dot} 2H{sub 2}O). These materials have little commercial use. Experiments were carried out that were meant to explore the feasibility of using blends of hannebachite and fly ash mixed with concentrated sodium hydroxide to make masonry products. The results suggest that some of these mixtures could be used in place of conventional Portland cement based products such as retaining wall bricks and pavers.


    SciTech Connect

    Anton, D.; James, C.; Cortes-Concepcion, J.; Tamburello, D.; Brinkman, K.; Gray, J.


    To make commercially acceptable condensed phase hydrogen storage systems, it is important to understand quantitatively the risks involved in using these materials. A rigorous set of environmental reactivity tests have been developed based on modified testing procedures codified by the United Nations for the transportation of dangerous goods. Potential hydrogen storage material, 2LiBH4{center_dot}MgH2 and NH3BH3, have been tested using these modified procedures to evaluate the relative risks of these materials coming in contact with the environment in hypothetical accident scenarios. It is apparent that an ignition event will only occur if both a flammable concentration of hydrogen and sufficient thermal energy were available to ignite the hydrogen gas mixture. In order to predict hydride behavior for hypothesized accident scenarios, an idealized finite element model was developed for dispersed hydride from a breached system. Empirical thermodynamic calculations based on precise calorimetric experiments were performed in order to quantify the energy and hydrogen release rates and to quantify the reaction products resulting from water and air exposure. Both thermal and compositional predictions were made with identification of potential ignition event scenarios.

  8. Weathering rates of marble in laboratory and outdoor conditions

    SciTech Connect

    Yerrapragada, S.S.; Chirra, S.R.; Jaynes, J.H.; Bandyopadhyay, J.K.; Gauri, K.L.; Li, S.


    In the modern urban atmosphere SO{sub 2} and NO{sub 2} attack calcite (CaCO{sub 3}) in marble exposed at rain-sheltered surfaces creating largely gypsum (CaSO{sub 4}{center_dot}2H{sub 2}O) crusts that eventually exfoliate. In combination with CO{sub 2} these gases erode the marble at unsheltered surfaces. the authors report the development of mathematical models to predict the rate of growth of crust and the rate of surface recession. To determine the rate of growth of crust the kinetic rate constant, diffusion rate, and the order of reaction were determined by the application of the shrinking-core model applied to data generated in laboratory experiments. Based on these parameters /and average ambient levels of 10 parts per billion (ppb) SO{sub 2} and 25 ppb NO{sub 2} in Louisville, Ky., the rate of crust formation for this metro area was calculated to be 1.8 {micro}m in the first year. However, the rate of recession was modeled from data obtained by exposing marble slabs to rainfalls. A surface recession of 15 {micro}m/yr was calculated. The models predicted well the rate of growth of crust observed at several sites in Louisville and the predicted surface recession compared well with values reported in the literature.

  9. Measurement of the Decay B- to D*0 e- anti-nu_e

    SciTech Connect

    Aubert, B.


    Using 226 million B{bar B} events recorded on the {Upsilon}(4S) resonance with the BABAR detector at the SLAC e{sup +}e{sup -} PEP-II storage rings, they reconstruct B{sup -} {yields} D*{sup 0}e{sup -}{bar {nu}}{sub e} decays using the decay chain D*{sup 0} {yields} D{sup 0}{pi}{sup 0} and D{sup 0} {yields} K{sup -} {pi}{sup +}. From the dependence of their differential rate on the w, the dot product of the four-velocities of B{sup -} and D*{sup 0}, and using the form factor description by Caprini et al. with the parameters F(1) and {rho}{sub 1{sub 1}}{sup 2}, they obtain the results {rho}{sub A{sub 1}}{sup 2} = 1.16 {+-} 0.06 {+-} 0.08, F(1) {center_dot} |V{sub cb}| = (35.9 {+-} 0.6 {+-} 1.4) {center_dot} 10{sup -3}, and {beta}(B{sup -} {yields} D*{sup 0} e{sup -}{bar {nu}}{sub e}) = (5.56 {+-} 0.08 {+-} 0.41)%.


    SciTech Connect

    Robert C. Brown; Maohong Fan; Adrienne Cooper


    Absorption of sulfur dioxide from a simulated flue gas was investigated for the production of polymeric ferric sulfate (PFS), a highly effective coagulant useful in treatment of drinking water and wastewater. The reaction for PFS synthesis took place near atmospheric pressure and at temperatures of 30-80 C. SO{sub 2} removal efficiencies greater than 90% were achieved, with ferrous iron concentrations in the product less than 0.1%. A factorial analysis of the effect of temperature, oxidant dosage, SO{sub 2} concentration, and gas flow rate on SO{sub 2} removal efficiency was carried out, and statistical analyses are conducted. The solid PFS was also characterized with different methods. Characterization results have shown that PFS possesses both crystalline and non-crystalline structure. The kinetics of reactions among FeSO{sub 4} {center_dot} 7H{sub 2}O, NaHSO{sub 3} and NaClO{sub 3} was investigated. The PFS product was used in pilot-scale tests at a municipal water treatment facility and gave good results in removal of turbidity and superior results in removal of disinfection byproduct precursors (TOC, DOC, UV-254) when compared with equal doses of ferric chloride.

  11. Electroluminescence cells based on the lamellar solid hydrogen uranyl phosphate

    SciTech Connect

    Dieckmann, G.R.,; Ellis, A.B.; Hellstrom, E.E. )


    Electroluminescence (EL) cells have been constructed with the layered, ionically conducting solid, hydrogen uranyl phosphate, HUO{sub 2}PO{sub 4} {center dot} 4H{sub 2}O (HUP), as the emissive medium. With ac excitation, both uranyl emission and molecular nitrogen plasma emission are observed, with the latter appearing to excite the former; the uranyl EL spectrum matches the photoluminescence spectrum of the solid. Similar results were obtained with fully substituted sodium (NaUP), magnesium (Mg{sub 0.5}UP), and pyridinium (pyHUP) derivatives of HUP. For all of these solids, the dependence of the EL intensity on sample thickness, ac frequency, and applied voltage has been determined. Typical operating conditions are 1.5--3.0 kV at 0.2--4 kHz. Impedance measurements permitted acquisition of dielectric constants and ionic conductivities for these solids, both of which decrease in the order HUP {gt} NaUP {gt} Mg{sub 0.5}UP {gt} pyHUP. A model describing the dependence of EL intensity on cell parameters is presented.

  12. Decomposition of chrysotile asbestos by fluorosulfonic acid

    SciTech Connect

    Sugama, T.; Sabatini, R.; Petrakis, L.


    The effect of a fluorosulfonic acid (FSO{sub 3}H) aqueous solution on decomposing the chrysotile asbestos fibers was investigated by using FT-IR, XRD, and XPS. From the equilibrium of FSO{sub 3}H in an aqueous medium (FSO{sub 3}H + H{sub 2}O = HF + H{sub 2}SO{sub 4}), the resulting H{sub 2}SO{sub 4} had a strong affinity for the external Mg(OH){sub 2} layers in the tubular, scroll-like chrysotile structure. This acid-base reaction led to the precipitation and lixiviation of MgSO{sub 4}{center_dot}H{sub 2}O, MgO, and Mg{sup 2+} ion. Once the breakage of the outer Mg(OH){sub 2} layers occurred, HF readily diffused into the inner silicious layers and then reacted with silicates, converting them into SiO{sub 2} hydrate and H{sub 2}SiF{sub 6}, while the ionic reaction between lixiviated Mg{sup 2+} and F{sup {minus}} resulted in precipitating MgF{sub 2}, thereby destroying the fibrous nature of the asbestos. An optimum combination of HF and H{sub 2}SO{sub 4} contributed significantly to enhancing the rate of conversion of asbestos into nonfibrous materials in a short treatment time without any physical agitation.

  13. Proton NMR and {mu}SR in Mn{sub 12}O{sub 12} acetate: A mesoscopic magnetic molecular cluster

    SciTech Connect

    Lascialfari, A.; Gatteschi, D.; Borsa, F. |; Shastri, A.; Jang, Z.H.; Carretta, P.


    The spin dynamics of Mn spins in the dodecanuclear manganese cluster of formula [Mn{sub 12}O{sub 12}(CH{sub 3}COO){sub 16}(H{sub 2}O){sub 4}]{center_dot}2CH{sub 3}-COOH{center_dot}4H{sub 2}O(Mn{sub 12}) has been investigated by {sup 1}HNMR and muon spin-lattice relaxation rate 1/T{sub 1} as a function of temperature (10{endash}400 K) and external magnetic field (0{endash}9.4 T). At room temperature, the proton 1/T{sub 1} depends on the measuring frequency. The results can be interpreted in terms of a slow decay of the Mn electronic-spin autocorrelation function, a feature characteristic of the almost zero dimensionality of the system. As the temperature is lowered, 1/T{sub 1} displays a critical enhancement that can be related to the slowing down of the local spin fluctuations as the cluster approaches the condensation into the total spin S=10 ground-state configuration. It is found that the application of an external magnetic field greatly depresses the enhancement of 1/T{sub 1} an effect that could be related to the superparamagnetic behavior of the Mn{sub 12} molecule. {copyright} {ital 1998} {ital The American Physical Society}

  14. Adjuvant Therapeutic Modalities in Primary Small Cell Carcinoma of Esophagus Patients

    PubMed Central

    Zou, Bingwen; Li, Tao; Zhou, Qiang; Ma, Daiyuan; Chen, Yongshun; Huang, Meijuan; Peng, Feng; Xu, Yong; Zhu, Jiang; Ding, Zhenyu; Zhou, Lin; Wang, Jin; Ren, Li; Yu, Min; Gong, Youling; Li, Yanying; Chen, Longqi; Lu, You


    Abstract To evaluate the treatment pattern and survival of patients receiving radical resection for primary small cell carcinoma of the esophagus (PSCCE). This retrospective study included 150 patients who received radical resection of PSCCE. Data were retrieved from 4 centers in Western China. Thirty-nine of 150 patients received postoperative chemo-radiotherapy, 62 received postoperative chemotherapy, and 49 received radical resection only. The median radiation dosage was 50 Gy. The chemotherapeutic regimen was platinum-based and lasted for 2 to 6 cycles (median, 3). Median disease-free survival (mDFS) and overall survival (mOS) were 12.0 and 18.3 months, respectively. Subgroup analysis revealed that postoperative therapy did not improve survival in limited stage I (LSI) disease, whereas postoperative chemotherapy improved survival in limited stage II (LSII) disease. Relative to chemotherapy alone, chemoradiotherapy did not improve survival in patients with completely resected LSII disease. A multivariate analysis indicated an association of no postoperative chemotherapy with shorter DFS (P = 0.050) and OS (P = 0.010). Higher lymph node stage and length of disease longer than 3 cm were poor prognostic factors for both DFS and OS. Adjuvant chemotherapy improves survival in PSCCE patients with completely resected LSII disease. Adjuvant treatment with postoperative chemotherapy alone or postoperative chemo-radiotherapy does not increase survival in completely resected LSI disease. PMID:27124057

  15. Sub-surface deposits of hydrous silicates or hydrated magnesium sulfates as hydrogen reservoirs near the Martian equator : plausible or not?

    SciTech Connect

    Fialips, C. I.; Carey, J. W.; Vaniman, D. T.; Feldman, W. C.; Bish, D. L.; Mellon, M. T.


    Neutron maps obtained using the neutron spectrometer (NS) and the high-energy neutron detector aboard the Mars Odyssey spacecraft reveal variations in the concentration of hydrogen over the martian low to middle latitudes, with up to {approx}10 wt% water-equivalent hydrogen in some equatorial regions. Infrared spectroscopic data provide evidence of chemically and/or physically bound H{sub 2}O and/or OH. Likewise, the decrease in flux of epithermal neutrons in Arabia Terra and southwest of Olympus Mons has been attributed to enhanced concentration of water-bearing minerals in the subsurface. The near-surface martian regolith is expected to contain both unweathered and weathered materials. It may contain significant and heterogeneously distributed amounts of hydrous minerals, such as clays, zeolites, and/or salt hydrates, such as MgSO{sub 4} {center_dot} nH{sub 2}O. Experimental studies suggest that if such water-bearing minerals formed in the past on the martian surface, they may retain significant amounts of water under present martian surface conditions. Hydrous minerals could thus account for some or all of the water observed in the martian regolith by Odyssey. Our study uses surface P-T data to predict regions of stability and the hydration state of selected water-bearing minerals from low to middle latitudes and to identify the nature and amount of hydrous minerals that could possibly account for the water observed by NS.

  16. An aptamer-based biosensor for sensitive thrombin detection with phthalocyanine@SiO2 mesoporous nanoparticles.


    Jiang, Zhou; Yang, Tingting; Liu, Minyan; Hu, Yanli; Wang, Jian


    Silica nanoparticles, with entrapped hydrophobic photosensitizer tetra-α-(2, 4-di-tert-butylphenoxy)-phthalocyaninato zinc (ZnPc(OAr)4), were synthesized by hydrolyzing triethoxyvinylsilane (TEVS) and 3-amino propyl triethoxysilane (APTES). The as-prepared nanoparticles, which were highly monodispersed spheres (about 100 nm), exhibited strong Q-band absorption of ZnPc(OAr)4 centered at 701 nm. The aqueous solubility of ZnPc(OAr)4 encapsulated in silica nanoparticles was obviously improved. The nanoparticles efficiently generated singlet oxygen ((1)O2) both in organic and aqueous solutions after being irradiated at suitable wavelength. The resulting (1)O2 then initiated chemiluminescence (CL) by reacting with a methyl cypridina luciferin analog (MCLA). Based on the photoinduced CL, a sensitive aptamer-based sandwich-type sensor was presented to detect human thrombin. Thrombin was first attached to Pc@SiO2 via secondary aptamer, and then they were collected, for CL determination, by beads with primary aptamer. The proposed approach, which was highly selective with a low detection limit of 80 pmol/L, minimized the nonspecific adsorption. Such an aptamer-based biosensor is feasible in screening biomarkers in complex matrices at ultratrace levels. PMID:24176970

  17. Dax1 Associates with Esrrb and Regulates Its Function in Embryonic Stem Cells

    PubMed Central

    Uranishi, Kousuke; Sun, Chuanhai; Koide, Hiroshi


    Self-renewal capacity and pluripotency, which are controlled by the Oct3/4-centered transcriptional regulatory network, are major characteristics of embryonic stem (ES) cells. Nuclear hormone receptor Dax1 is one of the crucial factors in the network. Here, we identified an orphan nuclear receptor, Esrrb (estrogen-related receptor beta), as a Dax1-interacting protein. Interaction of Dax1 and Esrrb was mediated through LXXLL motifs of Dax1 and the activation- and ligand-binding domains of Esrrb. Furthermore, Esrrb enhanced the promoter activity of the Dax1 gene via direct binding to Esrrb-binding site 1 (ERRE1, where “ERRE” represents “Esrrb-responsive element”) of the promoter. Expression of Dax1 was suppressed followed by Oct3/4 repression; however, overexpression of Esrrb maintained expression of Dax1 even in the absence of Oct3/4, indicating that Dax1 is a direct downstream target of Esrrb and that Esrrb can regulate Dax1 expression in an Oct3/4-independent manner. We also found that the transcriptional activity of Esrrb was repressed by Dax1. Furthermore, we revealed that Oct3/4, Dax1, and Esrrb have a competitive inhibition capacity for each complex. These data, together with previous findings, suggest that Dax1 functions as a negative regulator of Esrrb and Oct3/4, and these molecules form a regulatory loop for controlling the pluripotency and self-renewal capacity of ES cells. PMID:23508100

  18. Recovery and utilization of gypsum and limestone from scrubber sludge. Final technical report, September 1, 1992--August 31, 1993

    SciTech Connect

    Kawatra, S.K.; Eisele, T.C.


    Wet flue-gas desulfurization units in coal-fired power plants produce a large amount of sludge which must be disposed of, and which is currently landfilled in most cases. Increasing landfill costs are gradually forcing utilities to find other alternatives. In principle, this sludge can be used to make gypsum (CaSO{sub 4}{center_dot}2H{sub 2}O) for products such as plaster-of-Paris and wallboard, but only if impurities such as unreacted limestone and soluble salts are removed, and the calcium sulfite (CaSO{sub 3}) is oxidized to calcium sulfate (CaSO{sub 4}). This project investigated methods for removing the impurities from the sludge so that high-quality, salable gypsum products can be made. Two processes were studied, both separately and in combination: Water-only cycloning, and froth flotation. A large fraction (30--40%) of the impurities in the sludge are contained in the coarser, higher-density particles, which are readily removed using a water-only cyclone. Much of the remaining impurities are hydrophobic, and can be removed by froth flotation. A combined cyclone/froth flotation process has been found to be suitable for producing a high-purity product from scrubber sludge at low cost.

  19. Activation of the nickel-deficient carbon monoxide dehydrogenase from Rhodospirillum rubrum: Kinetic characterization and reductant requirement

    SciTech Connect

    Ensign, S.A.; Campbell, M.J.; Ludden, P.W. )


    The requirements for and kinetics of the activation of the nickel-deficient (apo) CO dehydrogenase from Rhodospirillum rubrum by exogenous nickel have been investigated. The activation is strictly dependent upon the presence of a low-potential one-electron reductant. Sodium dithionite and reduced methylviologen are suitable reductants, whereas reduced indigo carmine and the two-electron reductants sodium borohydride, NADH, and dithiothreitol are ineffective in stimulating activation. The midpoint potential for activation was observed at approximately {minus}475 mV. The ability of a reductant to stimulate activation is correlated with the reduced state of the enzyme Fe{sub 4}-S{sub 4} centers. The activation follows apparent first-order kinetics in a saturable fashion, yielding a rate constant of 0.157 min{sup {minus}1} at saturating concentration of nickel. The initial rate at which the enzyme is activated by NiCl{sub 2} is also a saturable process, yielding a dissociation constant (K{sub D}) of 755 {mu}M for the initial association of nickel and enzyme. Cadmium(II), zinc(II), cobalt(II), and iron(II) are competitive inhibitors of nickel activation with inhibition constants of 2.44, 4.16, 175, and 349 {mu}M, respectively. Manganese(II), calcium(II), and magnesium(II) exhibit no inhibition of activation.

  20. In situ encapsulation bench-scale demonstration report FY-94 (for TTP-ID 142012)

    SciTech Connect

    Weidner, J.R.; Shaw, P.G.


    This report describes the test objectives, procedures, and results of the laboratory-scale tests of in situ waste encapsulation of buried waste using a synthetic analogue of natural cement. The products of the reaction FeSO{sub 4} {center_dot} 7H{sub 2}O + Ca(OH){sub 2} = gypsum and iron oxide/hydroxide were examined as a possible waste encapsulation material for application at the Subsurface Disposal Area at the Idaho National Engineering Laboratory. This technique for transuranic waste encapsulation is being pursued by the Buried Waste Integrated Demonstration as a possible candidate containment and stabilization method for geologic time. The data indicate that the iron waste encapsulation materials tested are appropriate choices for the intended purpose. Based on these observations and conclusions, full-scale tests are recommended to determine the performance of the iron waste isolation materials under field conditions and for extended time periods. The viscosity of the reagents indicates that jet grouting is probably an appropriate application method.

  1. Light-induced charge separation and storage in titanium oxide gels

    SciTech Connect

    Kuznetsov, A.I.; Kameneva, O.; Alexandrov, A.; Bityurin, N.; Marteau, Ph.; Chhor, K.; Kanaev, A.; Sanchez, C.


    We report on the interaction of light with a particular class of media--wet gels, which in contrast to sols of nanoparticles possess a macroscopic bulk structure, and which differ from conventional solids by the existence of the internal liquid-solid interface. We show, taking an absorption cross section of trapped electrons from Safrany, Gao, and Rabani [J. Phys. Chem. B 104, 5848 (2000)], that a separation of charges with quantum efficiency as high as 46% appears under the band-gap irradiation of titanium oxide gels: electrons are stored in the gel network as Ti{sup 3+} centers, whereas holes are stored in the liquid phase. Under a prolonged UV-laser irradiation, more than 14% of Ti{sup 4+} centers can be converted into Ti{sup 3+}. Their lifetime can be extremely long and exceeds months at room temperature. The trapped electrons are responsible for a 'dark' absorption continuum covering the spectral range from 350 nm to 2.5 {mu}m.

  2. Reinforcing of QA/QC programs in radiotherapy departments in Croatia: Results of treatment planning system verification

    SciTech Connect

    Jurković, Slaven; Švabić, Manda; Diklić, Ana; Smilović Radojčić, Đeni; Dundara, Dea; Kasabašić, Mladen; Ivković, Ana; Faj, Dario


    Implementation of advanced techniques in clinical practice can greatly improve the outcome of radiation therapy, but it also makes the process much more complex with a lot of room for errors. An important part of the quality assurance program is verification of treatment planning system (TPS). Dosimetric verifications in anthropomorphic phantom were performed in 4 centers where new systems were installed. A total of 14 tests for 2 photon energies and multigrid superposition algorithms were conducted using the CMS XiO TPS. Evaluation criteria as specified in the International Atomic Energy Agency Technical Reports Series (IAEA TRS) 430 were employed. Results of measurements are grouped according to the placement of the measuring point and the beam energy. The majority of differences between calculated and measured doses in the water-equivalent part of the phantom were in tolerance. Significantly more out-of-tolerance values were observed in “nonwater-equivalent” parts of the phantom, especially for higher-energy photon beams. This survey was done as a part of continuous effort to build up awareness of quality assurance/quality control (QA/QC) importance in the Croatian radiotherapy community. Understanding the limitations of different parts of the various systems used in radiation therapy can systematically improve quality as well.

  3. Heavy metals in wastewater: Modelling the hydroxide precipitation of copper(II) from wastewater using lime as the precipitant

    SciTech Connect

    Baltpurvins, K.A.; Burns, R.C.; Lawrance, G.A.


    The effect of effluent composition (Cl{sup {minus}}, SO{sub 4}{sup 2{minus}} or CO{sub 3}{sup 2{minus}}) on the efficiency of the hydroxide precipitation of Cu(II) modelling lime (CaO) as the precipitant has been predicted using the solubility domain approach and has been experimentally validated. Solubility domains were based on the phases that were found to be solubility-limiting for systems representing potential effluent chemical composition limits. The generated solubility domains generally encompassed the experimentally observed solubilities, thereby providing effluent treatment quality assurance ranges for the hydroxide precipitation process. The presence of gypsum (CaSO{sub 4{center_dot}}2H{sub 2}O) and calcite (CaCO{sub 3}) as secondary precipitates had little effect on the observed residual Cu(II) solubilities, with Cu(II) mobility being governed by the least-soluble kinetically precipitated (rather than thermodynamically favored) phase in the system under study.

  4. Reinforcing of QA/QC programs in radiotherapy departments in Croatia: results of treatment planning system verification.


    Jurković, Slaven; Svabić, Manda; Diklić, Ana; Smilović Radojčić, Deni; Dundara, Dea; Kasabašić, Mladen; Ivković, Ana; Faj, Dario


    Implementation of advanced techniques in clinical practice can greatly improve the outcome of radiation therapy, but it also makes the process much more complex with a lot of room for errors. An important part of the quality assurance program is verification of treatment planning system (TPS). Dosimetric verifications in anthropomorphic phantom were performed in 4 centers where new systems were installed. A total of 14 tests for 2 photon energies and multigrid superposition algorithms were conducted using the CMS XiO TPS. Evaluation criteria as specified in the International Atomic Energy Agency Technical Reports Series (IAEA TRS) 430 were employed. Results of measurements are grouped according to the placement of the measuring point and the beam energy. The majority of differences between calculated and measured doses in the water-equivalent part of the phantom were in tolerance. Significantly more out-of-tolerance values were observed in "nonwater-equivalent" parts of the phantom, especially for higher-energy photon beams. This survey was done as a part of continuous effort to build up awareness of quality assurance/quality control (QA/QC) importance in the Croatian radiotherapy community. Understanding the limitations of different parts of the various systems used in radiation therapy can systematically improve quality as well. PMID:23246197

  5. Separation of Flue-Gas Scrubber Sludge into Marketable Products

    SciTech Connect


    The reduction of sulfur oxides from high sulfur coal burning utility companies has resulted in the production of huge quantities of wet flue-gas desulfurization scrubber sludge. A typical 400 MW power station burning a coal containing 3.5% sulfur by weight and using a limestone absorbent would produce approximately 177,000 tons (dry weight) of scrubber sludge per year. This brownish colored, finely divided material contains calcium sulfite (CaSO{sub 3} {center_dot} 1/2 H{sub 2}O), calcium sulfate (CaSO{sub 4} {center_dot} 2H{sub 2}O), unreacted limestone (CaCO{sub 3}), and various other impurities such as fly-ash and iron oxide particles. The physical separation of the components of scrubber sludge would result in the re-use of this material. The primary use would be conversion to a highly pure synthetic gypsum. This technical report concentrates on the effect of baffle configuration on the separation of calcium sulfite/sulfate from limestone. The position of the baffles as they related to the feed inlet, and the quantity of the baffles were examined. A clean calcium sulfite/sulfate (less than 2.0% limestone by weight) was achieved with the combination of water-only cyclone and horizontally baffled column.

  6. Multiscale Assessment of Methylarsenic Reactivity in Soil. 2. Distribution and Speciation in Soil

    SciTech Connect

    M Shimizu; Y Arai; D Sparks


    Methylated forms of arsenic (As), monomethylarsenate (MMA) and dimethylarsenate (DMA), have historically been used as herbicides and pesticides. Because of their large application to agriculture fields and the toxicity of MMA and DMA, the distribution, speciation, and sorption of methylated As to soils requires investigation. Monomethylarsenate and DMA were reacted with a soil up to one year under aerobic and anaerobic conditions. Microsynchrotron based X-ray fluorescence ({mu}-SXRF) mapping studies showed that MMA and DMA were heterogeneously distributed in the soil and were mainly associated with iron oxyhydroxides, e.g., goethite, in the soil. Micro-X-ray absorption near edge structure (XANES) spectra collected from As hotspots showed MMA and DMA were demethylated to arsenate over one year incubation under aerobic conditions. Monomethylarsenate was methylated to DMA, and DMA was maintained as DMA over a 3 month incubation under anaerobic conditions. Arsenic-iron precipitation, such as the formation of scorodite (FeAsO{sub 4} {center_dot} 2H{sub 2}O), was not observed, indicating that MMA and DMA were mainly associated with Fe-oxyhydroxides as sorption complexes.

  7. Influence of the Torsion Angle in 3,3'-Dimethyl-2,2'-bipyridine on the Intermediate Valence of Yb in (C5Me5)2 Yb(3,3'-Me2-bipy)

    SciTech Connect

    Nocton, Grégory; Booth, Corwin H.; Maron, Laurent; Andersen, Richard A.


    The synthesis and X-ray crystal structures of Cp-2*Yb(3,3'-Me(2)bipy) and [Cp-2 Yb(3,3'-Me(2)bipy)][Cp-2 YbCl1.6I0.4]center dot CH2Cl2 are described. In both complexes, the NCCN torsion angles are approximately 40 degrees. The temperature-independent value of n(f) of 0.17 shows that the valence of ytterbium in the neutral adduct is multiconfigurational, in reasonable agreement with a CASSCF calculation that yields a n(f) value of 0.27; that is, the two configurations in the wave function are f(13)(pi(1))(1) and f(14)(pi(1))(0) in a ratio of 0.27:0.73, respectively, and the open-shell singlet lies 0.28 eV below the triplet state (n(f) accounts for f-hole occupancy; that is, n(f) = 1 when the configuration is f(13) and n(f) = 0 when the configuration is f(14)). A correlation is outlined between the value of nf and the individual ytterbocene and bipyridine fragments such that, as the reduction potentials of the ytterbocene cation and the free x,x'-R-2-bipy ligands approach each other, the value of nf and therefore the f(13):f(14) ratio reaches a maximum; conversely, the ratio is minimized as the disparity increases.

  8. A novel analytical method for the determination of residual moisture in plutonium dioxide: Supercritical fluid extraction/Fourier transform infrared spectroscopy

    SciTech Connect

    Martinez, A.M.; Hollis, W.K.; Rubin, J.B.; Taylor, C.M.V.; Jasperson, M.N.; Vance, D.E.; Rodriguez, J.B.


    A novel approach has been developed at the Los Alamos National Laboratory for the quantitative determination of moisture content in impure plutonium oxide. The method combines a commercial supercritical fluid extraction instrument using supercritical carbon dioxide (SCCO{sub 2}) with on-line detection using a high-pressure Fourier Transform Infrared Spectroscopy (FTIR) cell. The combined SCCO{sub 2}/FTIR system has been modified for use inside a fully enclosed glove box. A series of validation experiments were performed using a pure, surrogate oxide (ThO{sub 2}) and an inorganic hydrate (CaSO{sub 4}{center_dot}2H{sub 2}O). The level of agreement between LOI and SCCO{sub 2}/FTIR for the surrogate oxide is excellent. The results for the inorganic hydrate showed excellent correlation with the known amount of water present. Results obtained for a group of nominally pure PuO{sub 2} samples were verified by independent measurement. The results of SCCO{sub 2}/FTIR for impure PuO{sub 2} samples is consistently lower than the results of obtained from the current analytical method (Loss On Ignition), indicating that the current method is inadequate for analytical purposes. While further verification experiments of the SCCO{sub 2}/FTIR method are underway, these initial results suggest that SCCO{sub 2}/FTIR could be used as an alternative analytical method for the Materials Identification and Surveillance program.

  9. Theoretical approach for enhanced mass transfer effects in-duct flue gas desulfurization processes

    SciTech Connect

    Not Available


    During this reporting period, bench- and pilot-scale experiments have been concluded to measure mass transfer and kinetic rates at simulated duct injection conditions. Section 2 describes the tank reactor test results. Present work is focused on running the slurry absorption model for solution compositions which are representative of the tests performed in the stirred tank reactor. The slurry absorption model has been run successfully to simulate most of the clear solution experiments. Section 3 presents the results of a special study investigating the use of Epsom Salt (magnesium sulfate heptahydrate, MgSO{sub 4}{center dot}7H{sub 2}O) as an additive for in-duct dry injection to reduce the amount of water needed for humidification. Industrial grade Epsom Salt was injected into a 50-cfm pilot plant at {approximately}3.4 lb/h. Section 4 summarizes the status of slaking modification tests. The present study focuses on an evaluation of techniques for the production of a fine particulate Ca(OH){sub 2} during slaking. Section 5 reports on differential reactor (Task 4) tests. The reactor has been modified to allow contact of solids containing varying amounts of surface water with humidified flue gas for 10--120 s. Preliminary gas and wet solids experiments have been performed using lime/flyash mixtures containing 5--40 percent initial free moisture. 3 refs., 14 figs., 10 tabs.

  10. Microchemical investigations of dust emitted by a lead smelter

    SciTech Connect

    Sobanska, S.; Ricq, N.; Laboudigue, A.; Guillermo, R.; Bremard, C.; Laureyns, J.; Merlin, J.C.; Wignacourt, J.P.


    Dusts emitted by an important pyrometallurgical lead smelter have been sampled within the pipes of the grilling and furnace working units before and after the filtering systems, respectively. Particle size distribution, elementary analyses, and X-ray powder diffraction analysis indicate PbS, PbSO{sub 4}, PbSO{sub 4}{center_dot}PbO, Pb, ZnS small particles less than 5 {micro}m in size to contribute mainly to the current atmospheric pollution. Although at least 90% of dust are retained on the filters, the amounts of the respirable smaller particles are significantly larger in the current emission. The average chemical speciation was found to be analogous for the dust samples collected before and after the filters. The scanning electron microscopy associated with energy-dispersive X-ray analysis and Raman microspectrometry established the morphology and chemical composition at the level of individual particles. A lot of minor compounds were found as small heterogeneous individual particles in the heterogeneous particles of grilling dust. Among the homogeneous particles of furnace dust, amorphous C, {beta}-PbO, PbO-PbCl{sub 2}, FeO, CdS, CdSO{sub 4} were often detected as homogeneous mixtures with the major compounds within the particles.

  11. Synthesis and crystal structure of the coordination compound of pyridoxine with manganese sulfate

    SciTech Connect

    Furmanova, N. G. Verin, I. A.; Shyityeva, N.; Sulaimankulov, K. S.; Berdalieva, Zh.; Resnyanskii, V. F.; Duishenbaeva, A. T.


    The reaction of pyridoxine with manganese sulfate in an aqueous solution gave the coordination compound MnSO{sub 4} {center_dot} 2C{sub 8}H{sub 11}O{sub 3}N {center_dot} 2H{sub 2}O (I). The structure of I was determined from single-crystal X-ray diffraction data. In the centrosymmetric complex (sp. gr. P1-bar, Z = 1), the Mn atom is coordinated by two pyridoxine molecules and two water molecules, thus adopting an octahedral coordination. The sulfate anion is also at a center of symmetry and, consequently, is disordered. The pyridoxine molecules are coordinated to the metal atom through the oxygen atoms of the deprotonated hydroxyl group and the CH{sub 2}OH group that retains the hydrogen atom. The nitrogen atom is protonated in such a way that the heterocycle assumes a pyridinium character. The crystal structure also contains six water molecules of crystallization. A thermogravimetric study showed that the decomposition of I occurs in several successive steps, such as dehydration, the combustion of organic ligands, and the formation of an inorganic residue.

  12. Separation of flue-gas scrubber sludge into marketable products. Third year, first quarterly technical progress report Quarter No. 9, September 1, 1995--November 30, 1995

    SciTech Connect

    Kawatra, S.K.; Eisele, T.C.


    To reduce their sulfur emissions, many coal-fired electric power plants use wet flue-gas scrubbers. These scrubbers convert sulfur oxides into solid sulfate and sulfite sludge, which must then be disposed of This sludge is a result of reacting limestone with sulfur dioxide to precipitate calcium sulfite and calcium sulfate. It consists of calcium sulfite (CaSO{sub 3}{center_dot}0.5H{sub 2}O), gypsum (CaSO{sub 4}{center_dot}2H{sub 2}O), and unreacted limestone (CaCO{sub 3}) or lime (Ca(OH){sub 2}), with miscellaneous objectionable impurities such as iron oxides, silicates, and magnesium, sodium, and potassium oxides or salts. These impurities prevent many sludges from being utilized as a replacement for natural gypsum, and as a result they must be disposed of in landfills, which presents a serious disposal problem. Knowledge of scrubber sludge characteristics is necessary for the development of purification technologies which will make it possible to directly utilize scrubber sludges rather than landfilling them. This project is studying the use of minimal-reagent froth flotation as the purification process, using the surface properties of the particles of unreacted limestone to remove them and their associated impurities from the material, leaving a purified calcium sulfite/gypsum product.

  13. Al wire array implosion experiments on the inductive storage generator GIT-4

    SciTech Connect

    Baksht, R.B.; Datsko, I.M.; Kim, A.A.; Loginov, S.V.; Labetsky, A.Yu.; Shishlov, A.V.


    In High Current Electronics Institute the first successful wire array implosion experiments on the inductive storage generator GIT-4 with a long conductive plasma opening switch were carried out in 1989. Those experiments were aimed at obtaining the radiation with quantum energy below 1 keV. Recently the authors carried out aluminum wire array implosion experiments on the GIT-4 generator varying the value of mr{sub 0}{sup 2} parameter from 2.2 {center_dot} 10{sup {minus}5} to 2.4 {center_dot} 10{sup {minus}4} g {center_dot} cm at different charge voltage and at different values of downstream inductance. The aims were two-fold: (1) to obtain the {eta}-dependence of the K-shell radiation yield and determine the liner parameters which provide a maximum K-shell radiation yield; and (2) to study whether the liner resistance, its inductance and change of its inductance during implosion influence on the POS performance. The results of these experiments are presented.

  14. Optical integration and verification of LINC-NIRVANA

    NASA Astrophysics Data System (ADS)

    Moreno-Ventas, J.; Baumeister, H.; Bertram, Thomas; Bizenberger, P.; Briegel, F.; Greggio, D.; Kittmann, F.; Marafatto, L.; Mohr, L.; Radhakrishnan, K.; Schray, H.


    The LBT (Large Binocular Telescope) located in Mount Graham near Tucson/Arizona at an altitude of about 3200m, is an innovative project being undertaken by institutions from Europe and USA. The structure of the telescope incorporates two 8.4-meter telescopes on a 14.4 center-to-center common mount. This configuration provides the equivalent collecting area of a 12m single-dish telescope. LINC-NIRVANA is an instrument to combine the light from both LBT primary mirrors in an imaging Fizeau interferometer. Many requirements must be fulfilled in order to get a good interferometric combination of the beams, being among the most important plane wavefronts, parallel input beams, homotheticity and zero optical path difference (OPD) required for interferometry. The philosophy is to have an internally aligned instrument first, and then align the telescope to match the instrument. The sum of different subsystems leads to a quite ambitious system, which requires a well-defined strategy for alignment and testing. In this paper I introduce and describe the followed strategy, as well as the different solutions, procedures and tools used during integration. Results are presented at every step.

  15. Simulation of Adsorption of Carbon Dioxide and Methane on Graphene Sheet

    NASA Astrophysics Data System (ADS)

    Maiga, Sidi; Gatica, Silvina

    Carbon dioxide (CO2) and Methane (CH4) constitute 90% of the annual greenhouse emission. These gases are emitted from multitude of sources such as: power station, transportation fuels, industrial processes, and agricultural byproducts. Scientists around the globe are looking for materials capable of capturing, separating, and storing these gases. Graphene with its high specific surface area provides a great platform for gas adsorption and separation. Adsorption is defined as the attachment of atoms, or molecules of a gas, liquid or dissolved solid onto a surface, creating a film or monolayer of material onto the adsorbing surface. Using the Method of Grand Canonical Monte Carlo, we computed the adsorption of carbon dioxide (CO2) and methane (CH4) on a monolayer graphene sheet, at various temperatures for each gas. For each temperature, we compute the adsorption isotherm, Energy gas-surface and Energy gas-gas. We compare the uptake pressures of CO2 and CH4. Using the Ideal Adsorbed Solution Theory (IAST), we predict the selectivity of a mixture CO2/CH4. Center for Integrated Quantum Materials (CIQM), NSF Grant No. DMR-1231319.

  16. Crystal structures of cis-[Ru(bpy){sub 2}(PPh{sub 2}(o-tol))Cl][ClO{sub 4}]. 1.5 (CH{sub 2}Cl{sub 2}), a structure containing both ordered and disordered dichloromethane molecules of crystallization

    SciTech Connect

    Churchill, M.R.; Krajkowski, L.M.; Huynh, M.H.V.; Takeuchi, K.J.


    The complex cis-[Ru(bpy){sub 2}(PPh{sub 2}(o-tol))Cl][ClO{sub 4}]{center_dot}1.5 (CH{sub 2}Cl){sub 2} crystallizes from dichloromethane as the sesqui-dischloromethane solvate. The complex crystallizes in the monoclinic space group P2{sub 1}/n with Z=4. The structure was refined to R-5.50% for those 2552 independent reflections with F{sub o}>6{sigma}(F{sub o}). The octahedral Ru(II) cation is associated with the following bond lengths: Ru-PPh{sub 2}(o-tol)=2.360(3){angstrom}, Ru-Cl=2.433(2){angstrom} and Ru-N(bpy)=2.041(8)-2.095(8){angstrom}. Both the perchlorate anion and the dichloromethane molecules of solvation exhibit large amplitudes of vibration. One dichloromethane molecule lies in general position, the other lies about an inversion center and suffers from disorder.

  17. ZnVSe2O7 and Cd6V2Se5O21: new d10 transition-metal selenites with V(IV) or V(V) cations.


    Jiang, Hai-Long; Kong, Fang; Fan, Yang; Mao, Jiang-Gao


    Two new metal selenites with a combination of vanadium(IV) or vanadium(V) cations, namely, ZnVSe 2O 7 and Cd 6V 2Se 5O 21, have been synthesized by hydrothermal and high-temperature solid-state reactions, respectively. The structure of ZnVSe 2O 7 features a 3D network of vanadium(IV) selenite with 1D tunnels occupied by zinc(II) ions. The 3D network of vanadium(IV) selenite is formed by corner-sharing V (IV)O 6 octahedral chains bridged by selenite groups. In Cd 6V 2Se 5O 21, the interconnection of cadmium(II) ions by bridging and chelating selenite groups led to a 3D framework with large tunnels along the b axis, and the 1D chains of corner-sharing V (V)O 4 tetrahedra are inserted in the above large tunnels and are bonded to the cadmium selenite framework via Cd-O-V bridges. Both compounds exhibit broad emission bands in the blue-light region. Results of magnetic property measurements show there is significant antiferromagnetic interaction between V (4+) centers in ZnVSe 2O 7. The electronic structure calculations for both compounds have been also performed. PMID:18576595

  18. Hydroxyapatite ceramics from hydrothermally prepared powders

    SciTech Connect

    Lin, C.H.; Huang, C.W.; Chang, S.C.


    Hydroxyapatite (Ca{sub 5}(PO{sub 4}){sub 3}(OH)) is an effective material for artificial human bone production. Hydroxyapatite powders were hydrothermally produced in this work by reacting Ca(OH){sub 2} with Na{sub 3}PO{sub 4}{center_dot}12H{sub 2}O in an autoclave at various temperature and for various times. The particle size of hydroxyapatite was observed to be very fine, uniform, around 50 nm, as well as independent of reaction time. The hydroxyapatite powders were compacted and sintered at various temperatures for 2 hrs. The density, grain size, and hardness of the hydroxyapatite ceramics were measured and compared with those of the hydroxyapatite ceramics produced by the powders from the commercial source. The hydroxyapatite ceramics from the hydrothermal powders were found to have a higher density, smaller grain size, and higher hardness. After the hydroxyapatite ceramics were dipped in a simulated biological body liquid for 10 days, the density and hardness of the hydroxyapatite ceramics from the hydrothermal powders were less deteriorated than those of the hydroxyapatite ceramics from the commercial powder.

  19. New Sericostomatid Caddisflies (Trichoptera) from the Brazilian Subregion

    NASA Astrophysics Data System (ADS)

    Holzenthal, R. W.; Blahnik, R. J.


    The caddisfly family Sericostomatidae, with 20 genera and almost 100 species, is nearly cosmopolitan in distribution, but is absent from the Australasian region, has only a single species in the Oriental region, and occurs only in the southernmost regions of Africa and South America. Within its distribution, it displays 4 centers of species diversity: the southeastern United States, Europe and the western Palearctic, South Africa, and southern Chile. Five genera occur in the Neotropics: Chiloecia (1 species), Grumicha (1 species), Myotrichia (1 species), Notidobiella (3 species), and Parasericostoma (10 species), all occurring in southern Chile, except Grumicha, from southeast Brazil and adjacent Argentina. Recent collecting throughout South America, but especially in SE Brazil, has resulted in the discovery of 4 new species and an extension of the family's range in South America well beyond the Chilean subregion. The new taxa include: 1 new species of Grumicha from southeastern Brazil, 2 new species of Notidobiella from SE Brazil and Ecuador, respectively, and a new species, probably representing a new genus, from Amazonian Brazil. Males, females, and immatures of these new species are described and illustrated. Biogeographical implications suggest both recent dispersal as well as more ancient Gondwanan vicariant patterns.

  20. First results on lower hybrid current drive at 2. 45 GHz in ASDEX

    SciTech Connect

    Leuterer, F.; Soldner, F.X.; Buechse, R.; Carlson, A.; Eberhagen, A.; Fahrbach, H.; Gehre, O.; Hassenpflug, F.; Herrmann, W.; Janeschitz, G.; Kornherr, M.; Luce, T.; McKormick, K.; Monaco, F.; Muenich, M.; Murmann, H.; Pelicano, M.; Steuer, K.; Zouhar, M. ); Bartiromo, R.; DeAngelis, R.; Pericoli, V.; Santini, F.; Tuccillo, A. ); Bernabei, S.; Forrest, C. ); ASDEX-team


    A new lower hybrid system with 2.45 GHz/3 MW/1 sec has started operation on ASDEX. Current drive effects have been identified up to a density of {bar n}{sub e}=4.7 {center dot} 10{sup 13} cm{sup {minus}3}. Full current drive at I{sub p}=420 kV was achieved up to a density of {bar n}{sub e}=2.1 {center dot} 10{sup 13} cm{sup {minus}3}. The effeciency was maximum at {bar n}{sub e}=1.35 {center dot} 10{sup 13} cm{sup {minus}3} and reached {eta}=1.46 (10{sup 13} cm{sup {minus}3} {center dot} A {center dot} m/W). The electron temperature is peaking and reached peak values up to 6 keV, while the electron density profile flattens. Sawteeth have been stabilized up to a density of {bar n}{sub e}=3.4 {center dot} 10{sup 13} cm{sup {minus}3}. The global confinement times decreases with increasing rf-power. The scaling can be described by an offset linear relation. At low density global confinement is better during the LH-phase than in the OH-phase at the same total power input.

  1. Solubility of triuranyl diphosphate tetrahydrate (TDT) and Na autunite at 23 and 50 degrees C

    SciTech Connect

    Armstrong, Christopher R.; Felmy, Andrew R.; Clark, Sue B.


    In this report we present experimental solubility data for well-characterized triuranyl diphosphate tetrahydrate (TDT: (UO2)(3)(PO4)(2)center dot 4H(2)O) and Na autunite (Na[UO2PO4]center dot xH(2)O) at 23 and 50 degrees C in NaClO4-HClO4 solutions at pC(H+) = 2. Duplicate samples of TDT in 0.1, 0.5, 1.0, 2.0 and 5.0 in solutions were equilibrated at 23 and 50 degrees C. TDT solid was synthesized and characterized with ICP-OES, ATR-IR and powder XRD before and after solubility experiments. The pH of the suspensions were monitored throughout the experiments. Equilibrium was achieved from undersaturation with respect to TDT and oversaturation for Na autunite. Steady-state conditions were achieved in all cases within 82 d. TDT was unstable at ionic strengths above 0.1 m, where its complete conversion to Na autunite was observed. The ion-interaction model was used to interpret the experimental solubility data. The solubility product, log K-sp, for TDT was determined to be -49.7 and -51.3 at 23 and 50 degrees C respectively. log K for Na autunite was determined to be -24.4 (23 degrees C) and -24.1 +/- 0.2 (50 degrees C).

  2. 805 MHz Beta = 0.47 Elliptical Accelerating Structure R & D

    SciTech Connect

    S. Bricker; C. Compton; W. Hartung; M. Johnson; F. Marti; J. Popierlarski; R. C. York; et al


    A 6-cell 805 MHz superconducting cavity for acceleration in the velocity range of about 0.4 to 0.53 times the speed of light was designed. After single-cell prototyping, three 6-cell niobium cavities were fabricated. In vertical RF tests of the 6-cell cavities, the measured quality factors (Q{sub 0}) were between 7 {center_dot} 10{sup 9} and 1.4 {center_dot} 10{sup 10} at the design field (accelerating gradient of 8 to 10 MV/m). A rectangular cryomodule was designed to house 4 cavities per cryomodule. The 4-cavity cryomodule could be used for acceleration of ions in a linear accelerator, with focusing elements between the cryomodules. A prototype cryomodule was fabricated to test 2 cavities under realistic operating conditions. Two of the 6-cell cavities were equipped with helium tanks, tuners, and input coupler and installed into the cryomodule. The prototype cryomodule was used to verify alignment, electromagnetic performance, frequency tuning, cryogenic performance, low-level RF control, and control of microphonics.

  3. Biological determinants of photobioreactor design. 6th Quarterly report, October 1994--December 1994

    SciTech Connect

    Palsson, B.O.; Brown, G.G.


    A novel photobioreactor (PBR) system using light-emitting diodes (LEDs) as a sole light source was constructed and operated with continuous medium perfusion. Direct internal illumination by 680 nm LEDs could deliver as high as 50 mW/cm{sup 2} of light into the culture medium. Gas transfer by internal sparging had the capacity to transfer 250 mmol O{sub 2}/L culture/h. Nutritional limitations could be overcome by continuous perfusion, supplying the medium components to the culture without increasing osmolarity, while removing potentially inhibitory cellular wastes. When the PBR operated in a continuous perfusion mode with a perfusion rate of 6 reactor volumes a day (6 VVD), it could support ultra high-density algal cultures up to cell concentrations of 4{center_dot}10{sup 9} cells/mL and total cell volume fractions of 9.4% v/v (about 25 g dry weight/L). The oxygen production rate at its peak was 13 to 15 mmol/L culture/h. This performance represents the highest reported cell densities attained in photoautotrophic cultures. Continuous perfusion allowed for long-term stable oxygen production, while oxygen production in batch mode ceased when stationary phase was reached. The results presented suggest that PBR technology can still be significantly improved.

  4. ODMR and EPR investigations of Fe centers in KTaO3

    NASA Astrophysics Data System (ADS)

    Reyher, H.-J.; Faust, B.; Maiwald, M.; Hesse, H.


    The analysis of EPR spectra obtained from iron doped KTaO3 crystals in the as-grown state revealed three dominant iron centers: Fe3+-OI, axial Fe-centers with spin S = 3/2 and rhombic Fe3+. By comparison with data from literature possible assignments for the center with S = 3/2 are discussed. For the rhombic species the temperature dependence of the main parameters of the Spin- Hamiltonian was measured. The result makes it most plausible that only one rhombic iron center exists in KTaO3, in contrast with literature. The understanding of the EPR spectra allows us to assign transitions, observed at very low magnetic fields by optically detected magnetic resonance (ODMR), to this rhombic Fe center. On this basis, the magnetic circular dichroism (MCD) of this defect could be identified using the method of tagged-MCD. This spectrum is compared to the tagged-MCD of Fe3+-O1 and of axial Fe4+ centers, which may be generated metastably by optical charge transfer. Considerably different structures in the MCD spectra of both Fe3+ centers indicate different local surroundings and electronic states.

  5. Surface reactivity of iron oxide pigmentary powders toward atmospheric components: XPS, FESEM, and gravimetry of CO and CO{sub 2} adsorption

    SciTech Connect

    Ismail, H.M.; Cadenhead, D.A.; Zaki, M.I.


    The adsorption of carbon monoxide and carbon dioxide on a number of specially prepared {alpha}-Fe{sub 2}O{sub 3} samples was measured gravimetrically at 25 C. The samples were prepared from a steel-pickling waste (97 wt% FeSO{sub 4}{center_dot}7H{sub 2}O) by roasting the original material at 700 C for 5 h in air, oxygen, and nitrogen, Estimated surface coverages by the adsorbed CO and CO{sub 2} were made on the basis of nitrogen-adsorption-based surface areas, while the nature of the sample surfaces was investigated by both X-ray photoelectron spectroscopy (XPS) and field emission SEM (FESEM) techniques. In addition a depth profiling study utilizing a sputtering argon beam and XPS was undertaken. Morphological studies using FESEM showed that neither CO nor CO{sub 2} caused any significant structural changes. The nature of the resultant {alpha}-Fe{sub 2}O{sub 3} sample surfaces differed, with the degree of oxygenation decreasing in the order of preparatory gases: oxygen, (wet) air, nitrogen [IP(O), IP(A), and IP(N)]. The amounts of both CO and CO{sub 2} adsorbed decreased in the sample order IP(A) > IP(O) > IP(N), though in the case of CO adsorption, the amounts adsorbed on IP(A), and IP(O) were not greatly different. In all cases the amounts adsorbed represented only fractional coverage.

  6. A rapid and selective assay for measuring cell surface hydrophobicity of brewer's yeast cells.


    Straver, M H; Kijne, J W


    A rapid and selective assay was developed to measure cell surface hydrophobicity of brewer's yeast cells. During this so-called magnobead assay, bottom-fermenting yeast cells adhere to paramagnetic, polystyrene-coated latex beads which can easily be removed from the cell suspension by using a (samarium-cobalt) magnet. At pH 4 center dot 5, electrostatic repulsion between yeast cells and latex beads was found to be minimal and yeast cell adhesion was predominantly based on hydrophobic interactions. The percentage of cells adhering to the beads could be calculated and provided a measure for cell surface hydrophobicity. Cell surface hydrophobicity measured by the magnobead assay was found to yield similar results, as did determination of contact angles of water droplets on a layer of yeast cells, a standard method for measuring surface hydrophobicity. However, the magnobead assay has the following advantages: (i) it is a quick and simple method, and, more significantly, (ii) hydrophobicity can be measured under physiological conditions. Use of the magnobead assay confirmed that a higher level of cell surface hydrophobicity is correlated with stronger flocculence of brewer's lager yeast cells. PMID:8904332

  7. Auxiliary basis expansions for large-scale electronic structure calculations

    SciTech Connect

    Jung, Yousung; Sodt, Alexander; Gill, Peter W.M.; Head-Gordon, Martin


    One way to reduce the computational cost of electronic structure calculations is to employ auxiliary basis expansions to approximate 4 center integrals in terms of 2 and 3-center integrals, usually using the variationally optimum Coulomb metric to determine the expansion coefficients. However the long-range decay behavior of the auxiliary basis expansion coefficients has not been characterized. We find that this decay can be surprisingly slow. Numerical experiments on linear alkanes and a toy model both show that the decay can be as slow as 1/r in the distance between the auxiliary function and the fitted charge distribution. The Coulomb metric fitting equations also involve divergent matrix elements for extended systems treated with periodic boundary conditions. An attenuated Coulomb metric that is short-range can eliminate these oddities without substantially degrading calculated relative energies. The sparsity of the fit coefficients is assessed on simple hydrocarbon molecules, and shows quite early onset of linear growth in the number of significant coefficients with system size using the attenuated Coulomb metric. This means it is possible to design linear scaling auxiliary basis methods without additional approximations to treat large systems.

  8. Total shoulder arthroplasty outcome for treatment of osteoarthritis: a multicenter study using a contemporary implant.


    Wright, Thomas W; Flurin, Pierre-Henri; Crosby, Lynn; Struk, Aimee M; Zuckerman, Joseph D


    In this article, we present clinical results of primary total shoulder arthroplasty for osteoarthritis using an implant that provides dual eccentricity and variable neck and version angles for reconstruction of proximal humeral anatomy. Two hundred one patients with symptomatic osteoarthritis underwent 218 total shoulder arthroplasties with a fourth-generation anatomical shoulder and a replicator plate at 4 centers between August 1, 2006, and December 31, 2010. Fourth-generation implants allow for varying humeral neck and version angles and have dual eccentricity so as to be consistently able to cover the humeral head cut. At a mean follow-up of 3 years (minimum, 2 years), there was an 81% follow-up rate. At final follow-up, 3 objective measures were significantly (P < .05) improved over preoperative levels: average active elevation (preoperative, 92°; postoperative, 137°), active external rotation (pre, 15°; post, 42°), and active internal rotation (pre, S3; post, L2). The functional outcome scores that were significantly (P < .05) improved at final follow-up were Constant normalized (pre, 39; post, 79), Shoulder Pain and Disability Index (pre, 86; post, 20), Simple Shoulder Test (pre, 3.3; post, 10), UCLA Shoulder Rating Scale (pre, 13; post, 31), and American Shoulder and Elbow Surgeons Shoulder Assessment (pre, 33; post, 85). Complications were noted in 11% of the shoulders. The most common complications were rotator cuff failure (13, 6%) and infection (5, 2%). PMID:26566554

  9. Hydrothermal reactions of fly ash. Final report

    SciTech Connect

    Brown, P.W.


    The emphasis of the work done has been to determine the reactivities of two ashes believed to be representative of those generated. A bituminous ash and a lignitic ash have been investigated. The reactions of these ashes undergo when subjected to mild hydrothermal conditions were explored. The nature of the reactions which the ashes undergo when alkaline activators, calcium hydroxide and calcium sulfate are present was also investigated. It was determined that calcium silicate hydrate, calcium aluminate hydrate, and the calcium sulfoaluminate hydrate ettringite form under these conditions. It appears 3CaO{center_dot}Al{sub 2}O{sub 3}{center_dot}3CaSO{sub 4}{center_dot}32H{sub 2}O (ettringite) formation needs to be considered in ashes which contain significant amounts of sulfate. Therefore the stability region for ettringite was established. It was also determined that calcium silicate hydrate, exhibiting a high internal surface area, will readily form with hydrothermal treatment between 50{degrees} and 100{degrees}C. This phase is likely to have a significant capacity to take up heavy metals and oxyanions and this ability is being explored.

  10. Elucidating Oxygen Reduction Active Sites in Pyrolyzed Metal–Nitrogen Coordinated Non-Precious-Metal Electrocatalyst Systems

    PubMed Central


    Detailed understanding of the nature of the active centers in non-precious-metal-based electrocatalyst, and their role in oxygen reduction reaction (ORR) mechanistic pathways will have a profound effect on successful commercialization of emission-free energy devices such as fuel cells. Recently, using pyrolyzed model structures of iron porphyrins, we have demonstrated that a covalent integration of the Fe–Nx sites into π-conjugated carbon basal plane modifies electron donating/withdrawing capability of the carbonaceous ligand, consequently improving ORR activity. Here, we employ a combination of in situ X-ray spectroscopy and electrochemical methods to identify the various structural and functional forms of the active centers in non-heme Fe/N/C catalysts. Both methods corroboratively confirm the single site 2e– × 2e– mechanism in alkaline media on the primary Fe2+–N4 centers and the dual-site 2e– × 2e– mechanism in acid media with the significant role of the surface bound coexisting Fe/FexOy nanoparticles (NPs) as the secondary active sites. PMID:24817921

  11. Lethal and sublethal effects of copper on redbreast sunfish, Lepomis auritus

    SciTech Connect

    Esman, L.A.; La Point, T.W.


    The popularity of redbreast sunfish (Lepomis auritus) as a sport fishery has been steadily increasing in South Carolina and the southeastern region of the United States. However, little is known about the toxicological sensitivity of this species. Expanding urban and suburban development threatens an increasing number of Piedmont streams with point and nonpoint source toxic discharges. As a result, redbreast sunfish face a greater influx of heavy metals, including copper, into the environment. In addition, the soft waters (10--20 mg/L as CaCO{sub 3}) characteristic of South Carolina increases the bioavailability of metals causing increased toxicity to fish. The authors determined the effect of copper, as copper sulfate (CuSO{sub 4}{center_dot}5H{sub 2}O) on redbreast sunfish using a static renewal toxicity test, monitoring mortality at frequent intervals. The overall 96hr LC50 was 0.18 mg/L Cu. A critical concentration leading to rapid time-to-death appears to fall within the range of 0.15--0.28 mg/L Cu. Normal social behavior is important for successful propagation of this species in the wild. Preliminary testing indicates that predatory behavior is unaffected at concentrations up to 50% LC50. Ultimately, such stress will lower population fitness. Therefore, the authors are determining at what concentration they see behavioral effects on feeding (e.g. handling time, capture efficiency) begin. Results of these experiments expand the behavioral and toxicological data on this species.

  12. Results of Propellant Mixing Variable Study Using Precise Pressure-Based Burn Rate Calculations

    NASA Technical Reports Server (NTRS)

    Stefanski, Philip L.


    A designed experiment was conducted in which three mix processing variables (pre-curative addition mix temperature, pre-curative addition mixing time, and mixer speed) were varied to estimate their effects on within-mix propellant burn rate variability. The chosen discriminator for the experiment was the 2-inch diameter by 4-inch long (2x4) Center-Perforated (CP) ballistic evaluation motor. Motor nozzle throat diameters were sized to produce a common targeted chamber pressure. Initial data analysis did not show a statistically significant effect. Because propellant burn rate must be directly related to chamber pressure, a method was developed that showed statistically significant effects on chamber pressure (either maximum or average) by adjustments to the process settings. Burn rates were calculated from chamber pressures and these were then normalized to a common pressure for comparative purposes. The pressure-based method of burn rate determination showed significant reduction in error when compared to results obtained from the Brooks' modification of the propellant web-bisector burn rate determination method. Analysis of effects using burn rates calculated by the pressure-based method showed a significant correlation of within-mix burn rate dispersion to mixing duration and the quadratic of mixing duration. The findings were confirmed in a series of mixes that examined the effects of mixing time on burn rate variation, which yielded the same results.

  13. A randomized trial of prophylactic uterosacral ligament suspension at the time of hysterectomy for Prevention of Vaginal Vault Prolapse (PULS): design and methods.


    Alperin, Marianna; Weinstein, Milena; Kivnick, Seth; Duong, Thinh H; Menefee, Shawn


    The primary aim of this randomized trial is to evaluate whether a standardized uterosacral ligament suspension colpopexy (USLSC), added to a planned hysterectomy for an indication other than pelvic organ prolapse (POP), decreases the rate of subsequent vaginal vault prolapse in women without preoperative symptomatic POP. Secondary aims include comparison of perioperative complications, urinary, bowel and sexual functions between subjects with and without concomitant USLSC. If shown to be beneficial, the cost-effectiveness of prophylactic USLSC at the time of hysterectomy will be evaluated. This trial will be performed at 4 centers across the United States. The data will be analyzed by the data-coordinating center of the Southern California Kaiser Permanente. Standardized questionnaires and objective measurements will be obtained. The patients and providers performing assessments are masked to treatment assignment. The primary outcome, defined as absence of POP at/distal to the hymen on Pelvic Organ Prolapse Quantitative examination, will be determined 12 months post-operatively. Secondary outcomes include: no prolapse symptoms by questionnaires, and no treatment for POP besides the prophylactic study intervention. Additional follow-up occurs annually for a total of 5 years. Accrual is projected to take 3 years. Given cost and morbidity of surgical repair of post-hysterectomy prolapse, preventive strategies are of outmost importance. The risks and benefits of prophylactic USLSC have never been studied prospectively. This trial is designed to determine if USLSC is an appropriate clinical adjunct at the time of hysterectomy, with subsequent reduction of symptomatic POP. PMID:23587538

  14. Strongly luminous tetranuclear gold(I) complexes supported by tetraphosphine ligands, meso- or rac-bis[(diphenylphosphinomethyl)phenylphosphino]methane.


    Tanase, Tomoaki; Otaki, Risa; Nishida, Tomoko; Takenaka, Hiroe; Takemura, Yukie; Kure, Bunsho; Nakajima, Takayuki; Kitagawa, Yasutaka; Tsubomura, Taro


    A series of tetragold(I) complexes supported by tetraphosphine ligands, meso- and rac-bis[(diphenylphosphinomethyl)phenylphosphino]methane (meso- and rac-dpmppm) were synthesized and characterized to show that the tetranuclear Au(I) alignment varies depending on syn- and anti-arrangements of the two dpmppm ligands with respect to the metal chain. The structures of syn-[Au4 (meso-dpmppm)2X]X'3 (X = Cl; X' = Cl (4 a), PF6 (4 b), BF4 (4 c)) and syn-[Au4 (meso-dpmppm)2]X4 (X = PF6 (4 d), BF4 (4 e), TfO (4 f); TfO = triflate) involved a bent tetragold(I) core with a counter anion X incorporated into the bent pocket. Complexes anti-[Au4 (meso-dpmppm)2]X4 (X = PF6 (5 d), BF4 (5 e), TfO (5 f)) contain a linearly ordered Au4 string and complexes syn-[Au4 (rac-dpmppm)2X2]X'2 (X = Cl, X' = Cl (6 a), PF6 (6 b), BF4 (6 c)) and syn-[Au4 (rac-dpmppm)2]X4 (X = PF6 (6 d), BF4 (6 e), TfO (6 f)) consist of a zigzag tetragold(I) chain supported by the two syn-arranged rac-dpmppm ligands. Complexes 4 d-f, 5 d-f, and 6 d-f with non-coordinative large anions are strongly luminescent in the solid state (λmax = 475-515 nm, Φ = 0.67-0.85) and in acetonitrile (λmax = 491-520 nm, Φ = 0.33-0.97); the emission was assigned to phosphorescence from (3) [dσ*σ*σ* pσσσ] excited state of the Au4 centers on the basis of DFT calculations as well as the long lifetime (a few μs). The emission energy is predominantly determined by the HOMO and LUMO characters of the Au4 centers, which depend on the bent (4), linear (5), and zigzag (6) alignments. The strong emissions in acetonitrile were quenched by chloride anions through simultaneous dynamic and static quenching processes, in which static binding of chloride ions to the Au4 excited species should be the most effective. The present study demonstrates that the structures of linear tetranuclear gold(I) chains can be modified by utilizing the stereoisomeric tetraphosphines, meso- and rac-dpmppm, which may

  15. Evaluation of a Combined Ultraviolet Photocatalytic Oxidation(UVPCO)/Chemisorbent Air Cleaner for Indoor Air Applications

    SciTech Connect

    Hodgson, Alfred T.; Destaillats, Hugo; Hotchi, Toshifumi; Fisk,William J.


    buildings containing typical VOC sources. The magnitude of the expected increase will depend upon a number of interrelated factors. Series of experiments were conducted to determine if the oxidizer, sodium permanganate (NaMnO{sub 4}{center_dot}H{sub 2}O), has sufficient reaction rates and capacity to counteract formaldehyde and acetaldehyde production and enable a 50 % reduction in building ventilation rate without net increases in indoor aldehyde concentrations. A commercially produced filter element and two laboratory-fabricated media beds containing NaMnO{sub 4}{center_dot}H{sub 2}O chemisorbent media were evaluated. The effectiveness of a device for removal of formaldehyde, acetaldehyde and other VOCs was determined by measurement of concentrations immediately upstream and downstream of the device. In some experiments, conversion efficiencies and byproduct generation by the UVPCO device also were determined. Six experiments were conducted with the commercial filter element installed downstream of the UVPCO reactor. Eleven experiments were conducted with a single panel media bed (30 cm by 61 cm by 2.5 cm deep) installed downstream of the UVPCO reactor; in these, the effects of temperature and air residence time on conversion efficiency were examined. Two experiments were conducted with a four-panel, folded, media bed (approximately four times the size of the single panel bed) installed downstream of the reactor. Because the commercial unit contained activated carbon as an additional component, it was effective at removing lower volatility compounds that typically have low oxidation rates in the UVPCO reactor. The filter element also met the minimum efficiency objective for formaldehyde. However, the removal of acetaldehyde was less than required. The air residence time in the single panel bed was not optimized as the removal efficiencies for both formaldehyde and acetaldehyde were strongly inversely related to the air flow rate through the device. In addition, the

  16. International, collaborative assessment of limitations of chromosome-specific probes (CSP) and fluorescent in situ hybridization (FISH): Analysis of expected detections in 73,000 prenatal cases

    SciTech Connect

    Evans, M.I.; Henry, G.P.; Miller, W.A.


    FISH and CSP have been proposed to reduce karyotyping need. The purpose of this study was to assess the potential efficacy of CSP-FISH using currently available probes (13, 18, 21, X, & Y) in large, prenatal diagnostic centers. Results (1990-1993) from 7 centers in 4 countries were divided by those expected to be detectable by currently available probes, and those which would be missed assuming 10% probe efficacy. 72,994 karyotypes included 699 trisomy 21`s, 352 trisomy 18`s, 136 trisomy 13`s, 358 sex chromosome aneuploidies, 70 triploidies, and 855 others (translocations, inversions, deletions, markers). Of 2,613 abnormalities, 1,745 would be detectable (66.8%). [Detroit 55.7%, Stockholm 68.3%, Boston 52.6%, Denver 61.3%, Muenster 77.0%, London 84.5%, Philadelphia 69.4%]. Centers with high proportions of referrals for ultrasound anomalies had the highest CSP-FISH positives secondary to increased T 18 & 13. We conclude: (1) 73,000 karyotypes show relatively consistent incidences of the common trisomies, sex chromosome abnormalities, and other chromosome abnormalities among the centers. (2) The proportion expected detectable by FISH-CSP technology varies from 52.6% to 84.5%, averaging 66.8%. (3) 1/3 of the karyotypic abnormalities would be missed, and therefore, replacement of complete karyotyping with FISH would have unacceptably high false-negative rates for routine evaluation. (4) FISH-CSP, while useful when positive for anomalies, is not sufficient when negative to obviate the need for a complete karyotype.

  17. Prospective Genomic Characterization of the German Enterohemorrhagic Escherichia coli O104:H4 Outbreak by Rapid Next Generation Sequencing Technology

    PubMed Central

    Zentz, Emily B.; Leopold, Shana R.; Rico, Alain; Prior, Karola; Szczepanowski, Rafael; Ji, Yongmei; Zhang, Wenlan; McLaughlin, Stephen F.; Henkhaus, John K.; Leopold, Benjamin; Bielaszewska, Martina; Prager, Rita; Brzoska, Pius M.; Moore, Richard L.; Guenther, Simone; Rothberg, Jonathan M.; Karch, Helge


    An ongoing outbreak of exceptionally virulent Shiga toxin (Stx)-producing Escherichia coli O104:H4 centered in Germany, has caused over 830 cases of hemolytic uremic syndrome (HUS) and 46 deaths since May 2011. Serotype O104:H4, which has not been detected in animals, has rarely been associated with HUS in the past. To prospectively elucidate the unique characteristics of this strain in the early stages of this outbreak, we applied whole genome sequencing on the Life Technologies Ion Torrent PGM™ sequencer and Optical Mapping to characterize one outbreak isolate (LB226692) and a historic O104:H4 HUS isolate from 2001 (01-09591). Reference guided draft assemblies of both strains were completed with the newly introduced PGM™ within 62 hours. The HUS-associated strains both carried genes typically found in two types of pathogenic E. coli, enteroaggregative E. coli (EAEC) and enterohemorrhagic E. coli (EHEC). Phylogenetic analyses of 1,144 core E. coli genes indicate that the HUS-causing O104:H4 strains and the previously published sequence of the EAEC strain 55989 show a close relationship but are only distantly related to common EHEC serotypes. Though closely related, the outbreak strain differs from the 2001 strain in plasmid content and fimbrial genes. We propose a model in which EAEC 55989 and EHEC O104:H4 strains evolved from a common EHEC O104:H4 progenitor, and suggest that by stepwise gain and loss of chromosomal and plasmid-encoded virulence factors, a highly pathogenic hybrid of EAEC and EHEC emerged as the current outbreak clone. In conclusion, rapid next-generation technologies facilitated prospective whole genome characterization in the early stages of an outbreak. PMID:21799941

  18. Long term follow-up study to evaluate immunogenicity and safety of a single dose of live attenuated hepatitis a vaccine in children

    PubMed Central

    Mitra, Monjori; Shah, Nitin; Faridi, MMA; Ghosh, Apurba; Sankaranarayanan, VS; Aggarwal, Anju; Chatterjee, Suparna; Bhattacharyya, Nisha; Kadhe, Ganesh; Vishnoi, Gaurav; Mane, Amey


    Worldwide, viral hepatitis continues to be a cause of considerable morbidity and mortality. Mass immunization with a single dose of live attenuated HAV has been shown to significantly reduce disease burden in the community. This was a phase IV, 5-year follow up study carried out at 4 centers (Kolkata, Delhi, Mumbai and Chennai) across India. The subjects with antibody titer <20 mIU/mL at baseline were evaluated for long term immunogenicity. Of the 503 subjects enrolled, 349 subjects were baseline seronegative with an anti-HAV antibody titer <20 mIU/mL. Overall, 343 subjects could be followed up at some point of time during this 5 y post vaccination period. In the last year (60 months) of follow-up, 108 subjects (97.3%) of 111 subjects (who came for follow-up at the end of 5 y) had a protective antibody titer (anti-HAV antibody titer >20 mIU/mL). The seroconversion rates considering seroprotection levels of anti-HAV antibody titer >20 mIU/mL, following vaccination starting from 6 weeks, 6 months, 12 months, 24 months, 36 months, 48 months and 60 months were 95.1%, 97.9%, 98.3%, 96.2%, 97.8%, 92.6% and 97.3%, respectively. The geometric mean concentration (GMC) over the years increased from 64.9 mIU/mL at 6 weeks to 38.1 mIU/mL and 135.2 mIU/mL at 6 months and 12 months, respectively and was maintained at 127.1 mIU/mL at 60 months. In conclusion, the result of this 5-year follow up study showed that the single dose of live attenuated vaccine is well tolerated and provides long-term immunogenicity in healthy Indian children. PMID:26018443

  19. Long term follow-up study to evaluate immunogenicity and safety of a single dose of live attenuated hepatitis a vaccine in children.


    Mitra, Monjori; Shah, Nitin; Faridi, Mma; Ghosh, Apurba; Sankaranarayanan, V S; Aggarwal, Anju; Chatterjee, Suparna; Bhattacharyya, Nisha; Kadhe, Ganesh; Vishnoi, Gaurav; Mane, Amey


    Worldwide, viral hepatitis continues to be a cause of considerable morbidity and mortality. Mass immunization with a single dose of live attenuated HAV has been shown to significantly reduce disease burden in the community. This was a phase IV, 5-year follow up study carried out at 4 centers (Kolkata, Delhi, Mumbai and Chennai) across India. The subjects with antibody titer <20 mIU/mL at baseline were evaluated for long term immunogenicity. Of the 503 subjects enrolled, 349 subjects were baseline seronegative with an anti-HAV antibody titer <20 mIU/mL. Overall, 343 subjects could be followed up at some point of time during this 5 y post vaccination period. In the last year (60 months) of follow-up, 108 subjects (97.3%) of 111 subjects (who came for follow-up at the end of 5 y) had a protective antibody titer (anti-HAV antibody titer >20 mIU/mL). The seroconversion rates considering seroprotection levels of anti-HAV antibody titer >20 mIU/mL, following vaccination starting from 6 weeks, 6 months, 12 months, 24 months, 36 months, 48 months and 60 months were 95.1%, 97.9%, 98.3%, 96.2%, 97.8%, 92.6% and 97.3%, respectively. The geometric mean concentration (GMC) over the years increased from 64.9 mIU/mL at 6 weeks to 38.1 mIU/mL and 135.2 mIU/mL at 6 months and 12 months, respectively and was maintained at 127.1 mIU/mL at 60 months. In conclusion, the result of this 5-year follow up study showed that the single dose of live attenuated vaccine is well tolerated and provides long-term immunogenicity in healthy Indian children. PMID:26018443

  20. Designing lead-free and stable perovskite materials for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Sun, Yiyang; Zhang, Shengbai

    A critical barrier for large-scale deployment of the current perovskite solar materials is the use of Pb to achieve high power conversion efficiency. While this appears to be a technical issue, there are more fundamental reasons behind. The current research has mainly focused on the replacement of Pb by other elements, in particular, Sn. However, in halide perovskites (i.e., I-II-VII3 composition), Sn is in its less stable 2 + state. The formation of more stable 4 + centers in the Sn(II)-based materials under ambient conditions makes the device efficiency very low. Worse, there might be no other elements across the Periodic Table that can replace Pb while maintaining the desirable properties, such as band gap. Out-of-the-box ideas are therefore called for to stimulate the research in this field. In this talk, two approaches are proposed based on state-of-the-art first-principles calculations. Through a screening of chalcogenide perovskite materials, CaTiS3, BaZrS3, CaZrSe3, and CaHfSe3 have been predicted to have suitable band gaps for making solar cells. Among these materials, BaZrS3 have been synthesized experimentally. Another proposed approach is to introduce dual anions (i.e., splitting the anion sites) that allow the composition to satisfy charge neutrality, while replacing Pb by more environmentally benign elements. One of the candidate materials is CH3NH3BiSI2, which is predicted to have band gap around 1.4 eV and high optical absorption.

  1. Reduction of SeO{sub 4}{sup 2{minus}} anions and anoxic formation of iron(II)-Iron(III) hydroxy-selenate green rust

    SciTech Connect

    Refait, P.; Simon, L.; Genin, J.M.R.


    Iron(II)-iron(III) hydroxy-salts known as green rusts were recently discovered as minerals present in hydromorphic soils and sediments. Due to their high reactivity, they are envisioned as potential reducing agents of a number of pollutants such as nitrate, chromate, or selenate. The interaction of selenate ions with such iron(II)-containing hydroxy compounds was studied by monitoring the oxidation processes of the iron phases with transmission Moessbauer spectroscopy measured at 14 K and by following the evolution of Se(VI) in solution by capillary electrophoresis. This interaction involved the hydroxy-selenate green rust, a compound isomorphous to the hydroxy-sulfate GR(SO{sub 4}{sup 2{minus}}). Its chemical composition, Fe{sub y}{sup II}Fe{sub 2}{sup III}(OH){sub 2(y+2)}SeO{sub 4}{center_dot}8H{sub 2}O, varied with time since y starts at 5.5 and ends at 4. GR(SeO{sub 4}{sup 2{minus}}) was obtained from Fe(OH){sub 2} precipitates by simultaneous accumulation of SeO{sub 4}{sup 2{minus}} anions inside the solid phase and reduction of an equal amount of SeO{sub 4}{sup 2{minus}} anions to Se(IV) species. These species were found to be less mobile, partially bound to iron compounds and/or forming iron salts. Finally, the hydroxy-selenate GR2(SeO{sub 4}{sup 2{minus}}) can form without any other oxidizing agent than selenate itself.

  2. Synthesis and properties of a few 1-D cobaltous fumarates

    SciTech Connect

    Bora, Sanchay J.; Das, Birinchi K.


    Metal fumarates are often studied in the context of metal organic framework solids. Preparation, structure and properties of three cobalt(II) fumarates, viz. [Co(fum)(H{sub 2}O){sub 4}]{center_dot}H{sub 2}O 1, [Co(fum)(py){sub 2}(H{sub 2}O){sub 2}] 2, and [Co(fum)(4-CNpy){sub 2}(H{sub 2}O){sub 2}] 3 (fum=fumarate, py=pyridine, 4-CNpy=4-cyanopyridine) are described. All three are chain polymers involving bridging fumarato ligands between each pair of octahedral Co(II) centres, but while the first one is zigzag in structure, the latter two are linear. Indexed powder X-ray diffraction patterns, solid state electronic spectra and magnetic properties of the species are reported. Thermal decomposition behaviour of the compounds suggests that they may be suitable as precursors to make Co{sub 3}O{sub 4} via pyrolysis below 600 Degree-Sign C. - Graphical abstract: Structure and properties of three chain-polymeric cobalt(II) fumarates are described. Highlights: Black-Right-Pointing-Pointer Three fumarate bridged 1-D coordination polymers of cobalt(II) are reported. Black-Right-Pointing-Pointer While Co(II) fumarate pentahydrate is zigzag, the species having both pyridine and water as co-ligands are linear in structure. Black-Right-Pointing-Pointer Prominent lines in the powder X-ray diffraction patterns have been indexed. Black-Right-Pointing-Pointer Thermal decomposition of the species yields Co{sub 3}O{sub 4} as the final product.

  3. Novel alkaline earth copper germanates with ferro and antiferromagnetic S=1/2 chains

    SciTech Connect

    Brandao, Paula; Reis, Mario S; Gai, Zheng; Moreira Dos Santos, Antonio F


    Two new alkaline earth copper(II) germanates were hydrothermally synthesized: CaCuGeO4 center dot H2O (1) and BaCu2Ge3O9 center dot H2O (2), and their structures determined by single crystal X-ray diffraction. Compound (1) crystallizes in space group P2(1)/c with a=5.1320(2) angstrom, b=16.1637(5) angstrom, c=5.4818(2) angstrom, beta=102.609(2)degrees, V=443.76(3) angstrom(3) and Z=4. This copper germanate contains layers of composition [CuGeO4](infinity)(2-) comprising CuO4 square planes and GeO4 tetrahedra with calcium and water molecules in the inter-layer space. Compound (2) crystallizes in the Cmcm space group with a=5.5593(3) angstrom, b=10.8606(9) angstrom, c=13.5409(8) angstrom, V=817.56(9) angstrom(3) and Z=4. This structure contains GeO6 and CuO6 octahedra as well as GeO4 tetrahedra, forming a three-dimensional network of interconnecting six-membered ring channels. The magnetic susceptibility for both samples can be interpreted as S=1/2 chains, in agreement with the copper topology observed in the crystal structure. The susceptibility of (1) exhibits a Bonner-Fisher type behavior, resulting from antiferromagnetic intra-chain interactions without three-dimensional ordering down to 5 K-the lowest measured temperature. This observation, together with the absence of super-exchange paths between the copper chains, make this system particularly promising for the study of low dimensional magnetism. The magnetic properties of (2) show a very weak ferromagnetic near-neighbor interaction along the chain. In this compound a peak the chi T plot seems to indicate the onset of interchain antiferromagentic correlations. However, no ordering temperature is detected in the susceptibility data.

  4. Advanced sulfur control concepts for hot gas desulfurization technology. Quarterly report, April--June 1995

    SciTech Connect

    Harrison, D.P.


    Delivery of the Antek R-6000 total sulfur analyzer and modifications of the Shimadzu GC-14A gas chromatograph are scheduled for early July. Installation and calibration of these instruments will follow shortly. The atmospheric pressure electrobalance was used during the quarter for studies of the regeneration of FeS with O{sub 2}/N{sub 2} gas mixtures. Some anomalies in the data initially obtained required adjustment of balance sensitivity, reduction of sample size, and recalibration of the air rotameter. The authors are now confident that they can routinely obtain accurate and reproducible data with this unit. Definitive tests of effects of temperature, O{sub 2} concentration, and gas flow rate will be done next quarter. The high pressure electrobalance was put into service, and calibration experiments were started. Decomposition of CuSO{sub 4}{center_dot}5H{sub 2}O produced agreement with expected results. Heating of FeS in an O{sub 2}/N{sub 2} gas stream gave results in qualitative agreement with experiments using the atmospheric pressure electrobalance. Initial tests on effects of temperature, O{sub 2} concentration, and gas flow rate on the regeneration of FeS were done. Results were generally in agreement with expectations and with previous experiments on the atmospheric apparatus. Possible problems arose when the lowest range of the air mass flow controller was used. Fluctuation of the electrobalance signal in the early part of the regeneration experiment was an additional problem. Effort during the next quarter will focus on these problems and on definitive tests for FeS regeneration at elevated pressure. The Alonized fixed bed reactor pressure vessel was successfully leak tested early in the quarter. Other components of the fixed bed reactor system continued to arrive. Construction will begin in July along with installation of the analytical instruments.

  5. Luminescent blooming of dendronic carbon nanotubes through ion-pairing interactions with an Eu(III) complex.


    Maggini, Laura; Toma, Francesca Maria; Feruglio, Luigi; Malicka, Joanna M; Da Ros, Tatiana; Armaroli, Nicola; Prato, Maurizio; Bonifazi, Davide


    A multiwalled carbon nanotube (MWCNT) scaffold was covalently functionalized with a second-generation polyamidoamine (PAMAM) dendron, presenting four terminal amino groups per grafted aryl moiety. These reactive functions were alkylated to obtain a positively charged polycationic dendron/carbon nanotube system (d-MWCNTs⋅Cl), which eventually underwent anion exchange reaction with a negatively charged and highly luminescent Eu(III) complex ([EuL(4)]⋅NEt(4), in which L = (2-naphtoyltrifluoroacetonate)). This process afforded the target material d-MWCNTs⋅[EuL(4)], in which MWCNTs are combined with red-emitting Eu(III) centers through electrostatic interactions with the dendronic branches. Characterization of the novel MWCNT materials was accomplished by means of TGA and TEM, whereas d-MWCNTs⋅Cl and d-MWCNTs⋅ [EuL(4)] further underwent XPS, SEM and Raman analyses. These studies demonstrate the integrity of the luminescent [EuL(4)](-) center in the luminescent hybrid, the massive load of the cationic binding sites, and the virtually complete anion-exchange into the final hybrid material. The occurrence of the ion-pairing interaction with MWCNTs was unambiguously demonstrated through DOSY NMR diffusion studies. Photophysical investigations show that MWCNTs⋅[EuL(4)] is a highly soluble and brightly luminescent red hybrid material in which MWCNTs act as photochemically inert scaffolds with negligible UV/Vis absorption, compared with the grafted Eu complex, and with no quenching activity. The high dispersibility of MWCNTs⋅[EuL(4)] in a polymer matrix makes it a promising luminophore for applications in material science. PMID:22488679

  6. Organic oxalate as leachant and precipitant for the recovery of valuable metals from spent lithium-ion batteries

    SciTech Connect

    Sun Liang; Qiu Keqiang


    Graphical abstract: Display Omitted Highlights: Black-Right-Pointing-Pointer Vacuum pyrolysis as a pretreatment was used to separate cathode material from aluminum foils. Black-Right-Pointing-Pointer Cobalt and lithium can be leached using oxalate while cobalt can be directly precipitated as cobalt oxalate. Black-Right-Pointing-Pointer Cobalt and lithium can be separated efficiently from each other only in the oxalate leaching process. Black-Right-Pointing-Pointer High reaction efficiency of LiCoO{sub 2} was obtained with oxalate. - Abstract: Spent lithium-ion batteries containing lots of strategic resources such as cobalt and lithium are considered as an attractive secondary resource. In this work, an environmentally compatible process based on vacuum pyrolysis, oxalate leaching and precipitation is applied to recover cobalt and lithium from spent lithium-ion batteries. Oxalate is introduced as leaching reagent meanwhile as precipitant which leaches and precipitates cobalt from LiCoO{sub 2} and CoO directly as CoC{sub 2}O{sub 4}{center_dot}2H{sub 2}O with 1.0 M oxalate solution at 80 Degree-Sign C and solid/liquid ratio of 50 g L{sup -1} for 120 min. The reaction efficiency of more than 98% of LiCoO{sub 2} can be achieved and cobalt and lithium can also be separated efficiently during the hydrometallurgical process. The combined process is simple and adequate for the recovery of valuable metals from spent lithium-ion batteries.

  7. Mineralogical characterization of arsenic in gold mine tailings from three sites in Nova Scotia

    SciTech Connect

    M Corriveau; H Jamieson; M Parsons; G Hall


    Chronic exposure to high concentrations of arsenic (As) in windblown and vehicle-raised dust from tailings sites in Nova Scotia poses a potential health risk to recreational users of these areas and to nearby residents. The exposure may involve inhalation of dust, as well as oral ingestion of particles. It is important to understand the mineralogy and morphology of As-bearing dust particles in order to evaluate the risk posed by near-surface particulates in As-bearing tailings fields, as this will influence the stability and toxicity of As in the wastes. Optical mineralogy, scanning electron microscopy, electron microprobe, X-ray diffraction, synchrotron-based micro-X-ray diffraction ({mu}XRD) and micro-X-ray absorption near edge structure ({mu}XANES), and sequential leach extractions were applied to tailings samples from three sites in eastern Nova Scotia. Arsenic occurs naturally in these gold deposits mainly in arsenopyrite (FeAsS). In the near-surface material of the tailings fields, sulphide minerals have almost completely oxidized to secondary minerals such as scorodite (FeAsO{sub 4}{center_dot}2H{sub 2}O) and Ca-Fe arsenates. Iron oxyhydroxides contain variable amounts of As{sub 2}O{sub 5} from trace to 30 wt.% and CaO up to 8 wt.%. The presence of multiple As-hosting solid phases, including relatively soluble Ca-Fe arsenates and Fe oxyhydroxides with adsorbed As has important implications for human health risk assessment and remediation design.

  8. Revealing the Mechanisms behind SnO[subscript 2] Nanoparticle Formation and Growth during Hydrothermal Synthesis: An In Situ Total Scattering Study

    SciTech Connect

    Jensen, Kirsten M.Ø.; Christensen, Mogens; Juhas, Pavol; Tyrsted, Christoffer; Bøjesen, Espen D.; Lock, Nina; Billinge, Simon J.L.; Iversen, Bo B.


    The formation and growth mechanisms in the hydrothermal synthesis of SnO{sub 2} nanoparticles from aqueous solutions of SnCl{sub 4} {center_dot} 5H{sub 2}O have been elucidated by means of in situ X-ray total scattering (PDF) measurements. The analysis of the data reveals that when the tin(IV) chloride precursor is dissolved, chloride ions and water coordinate octahedrally to tin(IV), forming aquachlorotin(IV) complexes of the form [SnCl{sub x}(H{sub 2}O){sub 6-x}]{sup (4-x)+} as well as hexaaquatin(IV) complexes [Sn(H{sub 2}O){sub 6-y}(OH){sub y}]{sup (4-y)+}. Upon heating, ellipsoidal SnO{sub 2} nanoparticles are formed uniquely from hexaaquatin(IV). The nanoparticle size and morphology (aspect ratio) are dependent on both the reaction temperature and the precursor concentration, and particles as small as 2 nm can be synthesized. Analysis of the growth curves shows that Ostwald ripening only takes place above 200 C, and in general the growth is limited by diffusion of precursor species to the growing particle. The c-parameter in the tetragonal lattice is observed to expand up to 0.5% for particle sizes down to 2-3 nm as compared to the bulk value. SnO{sub 2} nanoparticles below 3-4 nm do not form in the bulk rutile structure, but as an orthorhombic structural modification, which previously has only been reported at pressures above 5 GPa. Thus, adjustment of the synthesis temperature and precursor concentration not only allows control over nanoparticle size and morphology but also the structure.

  9. Effectiveness and safety of the Proxis system in demonstrating retrograde coronary blood flow during proximal occlusion and in capturing embolic material.


    Sievert, Horst; Wahr, Dennis W; Schuler, Gerhard; Schofer, Joachim J; Sutsch, Gabor; Pavliska, Jim; Skowasch, Marijke


    The Feasibility And Safety Trial for its embolic protection device during transluminal intervention in coronary vessels: a European Registry (FASTER) was designed to demonstrate that (1) the Proxis embolic protection system can control anterograde flow and reverse blood flow in native coronary arteries and saphenous vein grafts; and (2) this system can capture embolic debris. Percutaneous coronary intervention on stenotic coronary lesions revolutionized treatment of coronary disease, but is associated with the risk of major adverse cardiac events. This prospective, nonrandomized, multicenter clinical feasibility and safety study enrolled 40 patients with 51 lesions at 4 centers who underwent treatment of stenotic lesions with proximal emboli protection (Proxis system). Proxis was successfully used 95% of the time, and embolic debris was qualitatively identified in all cases. Major adverse cardiac events occurred in 2 patients (5.0%): 1 late in-stent thrombosis resulting in death and 1 non-Q-wave infarction when a lesion was crossed before deployment of the Proxis system. Mean vessel occlusion time was 4.3 +/- 2.4 minutes. Native flow reversal was sufficient in 31 patients, with a mean aspirate volume of 11.8 +/- 6.5 ml. When the infusion catheter was used to augment reflow, mean occlusion time was 4.6 minutes. In conclusion, this trial is the first to demonstrate that retrograde blood flow can be achieved during proximal occlusion and that the Proxis system can be used safely during intervention of saphenous vein grafts and native coronary arterial lesions to capture embolic material. PMID:15518607

  10. Changes in Zinc Speciation with Mine Tailings Acidification in a Semiarid Weathering Environment

    SciTech Connect

    Hayes, Sarah M.; O’Day, Peggy A.; Webb, Sam M.; Maier, Raina M.; Chorover, Jon


    High concentrations of residual metal contaminants in mine tailings can be transported easily by wind and water, particularly when tailings remain unvegetated for decades following mining cessation, as is the case in semiarid landscapes. Understanding the speciation and mobility of contaminant metal(loid)s, particularly in surficial tailings, is essential to controlling their phytotoxicities and to revegetating impacted sites. In prior work, we showed that surficial tailings samples from the Klondyke State Superfund Site (AZ, USA), ranging in pH from 5.4 to 2.6, represent a weathering series, with acidification resulting from sulfide mineral oxidation, long-term Fe hydrolysis, and a concurrent decrease in total (6000 to 450 mg kg{sup -1}) and plant-available (590 to 75 mg kg{sup -1}) Zn due to leaching losses and changes in Zn speciation. Here, we used bulk and microfocused Zn K-edge X-ray absorption spectroscopy (XAS) data and a six-step sequential extraction procedure to determine tailings solid phase Zn speciation. Bulk sample spectra were fit by linear combination using three references: Zn-rich phyllosilicate (Zn{sub 0.8}talc), Zn sorbed to ferrihydrite (Zn{sub adsFeOx}), and zinc sulfate (ZnSO{sub 4} {center_dot} 7H{sub 2}O). Analyses indicate that Zn sorbed in tetrahedral coordination to poorly crystalline Fe and Mn (oxyhydr)oxides decreases with acidification in the weathering sequence, whereas octahedral zinc in sulfate minerals and crystalline Fe oxides undergoes a relative accumulation. Microscale analyses identified hetaerolite (ZnMn{sub 2}O{sub 4}), hemimorphite (Zn{sub 4}Si{sub 2}O{sub 7}(OH){sub 2} {center_dot} H{sub 2}O) and sphalerite (ZnS) as minor phases. Bulk and microfocused spectroscopy complement the chemical extraction results and highlight the importance of using a multimethod approach to interrogate complex tailings systems.

  11. Luminescence and creation of electron centers in UV-irradiated YAlO{sub 3} single crystals

    SciTech Connect

    Grigorjeva, L.; Krasnikov, A.; Zazubovich, S.; Laguta, V. V.; Nikl, M.


    Luminescence and defect creation processes were studied by the photoluminescence, thermally stimulated luminescence, and electron paramagnetic resonance methods in the UV-irradiated single crystals of undoped YAlO{sub 3}, containing small amounts of Ce, Mo, and Ti ions as accidental impurities. The luminescence of the electron antisite Y{sub Al}{sup 2+}-type centers of different structures was found around 2.45 eV and studied at 4.2-500 K. The luminescence of the Ti{sup 3+}-related centers (2.03 and 1.73 eV) and Ti{sup 4+} centers (2.78 eV) was observed as well. Dependences of the number of the Y{sub Al}{sup 2+}-type and Ti{sup 3+}-related centers on the UV irradiation energy, temperature, and duration, as well as on various crystal heat-treatment procedures were examined. As a result of the photostimulated electron transfer from the O{sup 2-} ligand ions to Mo{sup 4+} and Ti{sup 4+} ions, the paramagnetic hole O{sup -}-type centers and electron Ti{sup 3+} and Mo{sup 3+} centers are created. The antisite Y{sub Al}{sup 2+}-type centers are created due to the photostimulated release of electrons mainly from the Mo{sup 3+} centers to the conduction band and their subsequent trapping at the Y{sub Al}{sup 3+} ions located near an oxygen vacancy or a defect at the neighboring Y{sup 3+} site.

  12. Factors affecting expanded electricity trade in North America

    SciTech Connect

    Hill, L.J.


    The authors explore factors that affect electricity trade between enterprises in the US and Canada and the US and Mexico. They look to those underlying policy and institutional factors that affect the relative costs of producing electricity in the three countries. In particular, they consider six factors that appear to have a significant impact on electricity trade in North America: differences in the types of economic regulation of power leading to differences in cost recovery for wholesale and retail power and wheeling charges; changing regulatory attitudes, placing more emphasis on demand-side management and environmental concerns; differences in energy and economic policies; differences in national and subnational environmental policies; changing organization of electric power industries which may foster uncertainty, change historical relationships, and provide other potentially important sources of power for distribution utilities; and differences in the ability of enterprises to gain access to electric power markets because of restrictions placed on transmission access. In Section 2, the authors discuss the regulation of electricity trade in North America and provide an overview of the recent trading experience for electricity between Canada and the US and between Mexico and the US, including the volume of that trade over the past decade and existing transmission capacity between regions of the three countries. In Section 3, they look at the benefits that accrue to trading counties and what those benefits are likely to be for the three countries. The discussion in Section 4 centers on the relevant provisions of the Canada Free Trade Agreement and the proposed North American Free Trade Agreement. In Section 5, they set the stage for the discussion of policy and institutional differences presented in Section 6 by outlining differences in the organization of the electric power sectors of Canada, the US, and Mexico. The study is synthesized in Section 7.

  13. Transport of Impurity Ions in the Wendelstein 7-AS Stellarator Plasma

    SciTech Connect

    Burhenn, Rainer; Baldzuhn, Juergen; Beidler, Craig; Brakel, Rudolf; Ehmler, Hartmut; Giannone, Louis; Grigull, Peter; Hirsch, Matthias; Knauer, Jens; Krychowiak, Maciej; Maassberg, Henning; McCormick, Kent; Pasch, Ekkehard; Weller, Arthur; Ida, Katsumi


    The impact of global plasma parameters on impurity transport in the stellarator W7-AS was investigated by laser blow-off technique. Both, density and heating power were identified to have a strong influence on impurity confinement {tau}{sub I} {approx} n{sub e}{sup 1.2}/P{sub ECRH}{sup 0.8}. In spite of stationary conditions at lower densities, an increasing trend for accumulation was observed at plasma densities beyond 5{center_dot}1019 m-3 due to reduction of the diffusion coefficients. Up to densities of at least 9{center_dot}1019 m-3, launching of electron cyclotron resonance heating (ECRH) power of 1.2 MW is able to counteract the impurity accumulation by deterioration of the impurity confinement with heating power according to the scaling law as given above. In neutral beam injection (NBI) heated plasmas at densities higher than 1{center_dot}1020m-3, long confinement times were observed, often accompanied by loss of density control and degradation of plasma energy due to increasing radiation losses. The installation of island divertor allowed a general extension of the range of accessible densities up to 4{center_dot}1020m-3: beyond a certain power-dependent threshold density (1.5-2.1{center_dot}1020m-3), the plasma enters the High Density H-mode (HDH) regime and the impurity confinement time drops to values comparable to the energy confinement time. High density plasmas could be sustained quasi-stationary with a low level of impurity radiation. The favourable impurity behavior goes along with a reduction of the inward impurity convection in the core plasma and possible changes in the edge transport. For the characterization of the general impurity behavior in W7-AS plasmas the usual transport models for axisymmetric devices are not sufficient and additional stellarator specific processes have to be considered.

  14. Rare-earth-free red-emitting K2Ge4O9:Mn(4+) phosphor excited by blue light for warm white LEDs.


    Ding, Xin; Wang, Qian; Wang, Yuhua


    A series of novel K2Ge4O9:Mn(4+) phosphors with red emission under blue light excitation have been synthesized successfully by traditional high-temperature solid-state reaction. The structure of K2Ge4O9 has been investigated by high-resolution transmission electron microscopy, scanning electron microscopy and X-ray powder diffraction with Rietveld refinement. The PL properties have been investigated by measuring diffuse reflection spectra, emission spectra, excitation spectra, decay curves and temperature-dependent spectra. The KGO:0.1% Mn(4+) phosphor can emit red light peaking at 663 nm under UV or blue light excitation. The critical quenching concentration of Mn(4+) was about 0.1 mol%. The concentration quenching mechanism could be a d-d interaction for the Mn(4+) center. The CIE chromaticity coordinates and FWHM are (0.702, 0.296) and 20 nm, which demonstrated that the K2Ge4O9:Mn(4+) has a high color purity. By tuning the weight ratio of yellow and red phosphors, the fabricated white LEDs, using a 455 nm InGaN blue chip combined with a blend of the yellow phosphor YAG:Ce(3+) and the red-emitting KGO:Mn(4+) phosphor driven by a 40 mA current, can get white light with chromaticity coordinates (0.405, 0.356) and CCT 3119 K. These results indicated that K2Ge4O9:Mn(4+) is a potential red phosphor to match blue LED chips to get warm white light. PMID:26923078

  15. Synthesis, crystal structure, and electrode characteristics of LiMnPO{sub 4}(OH) cathode for lithium batteries

    SciTech Connect

    Yang, Yang; Hirayama, Masaaki; Yonemura, Masao; Kanno, Ryoji


    The electrochemical properties of lithium manganese hydroxyphosphate, LiMnPO{sub 4}(OH), with the tavorite structure have been investigated to assess its suitability as a cathode material for lithium batteries. Stoichiometric LiMnPO{sub 4}(OH) was synthesized by an ion-exchange reaction with MnPO{sub 4}{center_dot}H{sub 2}O and LiNO{sub 3}. Lithium (de)intercalation reaction was observed for the first time in the trivalent LiMnPO{sub 4}(OH), and it exhibited a reversible capacity of 110 mA h g{sup -1} with an average cell voltage of 3.4 V (vs. Li) after an irreversible phase change during the first charge process. The crystal structure has been refined at room temperature by neutron and synchrotron X-ray diffraction data using Rietveld method with a space group of P-1. The hydroxy group at a bottleneck may reduce the attraction force between lithium and the bottleneck oxygen ions that thus increase the ion mobility along the lithium diffusion tunnel. - Graphical abstract: Tavorite-type material LiMnPO{sub 4}(OH) shows lithium intercalation at an average voltage of 3.4 V (vs. Li) after a phase transition during the first charge-discharge. Highlights: Black-Right-Pointing-Pointer Tavorite-type LiMnPO{sub 4}(OH) nanoparticles as a cathode material for lithium battery. Black-Right-Pointing-Pointer Synchrotron XRD and neutron diffraction refinement of LiMnPO{sub 4}(OH). Black-Right-Pointing-Pointer Lithium intercalation reaction occurs in LiMnPO{sub 4}(OH) during charge-discharge. Black-Right-Pointing-Pointer A phase transition in the first charge, followed by a reversible reaction.

  16. Synthesis, structure, and reactivity of thienyl-, benzothienyl-, and selenylcarbene complexes of rhenium. A new mechanicm of H/D exchange during hydrodesulfurization

    SciTech Connect

    White, C.J.; Angelici, R.J. )


    A series of [eta][sup 1](E)-coordinated (E = S or Se) thiophene, benzo[b]thiophene and selenophene complexes [Cp(NO)(PPh[sub 3])Re([eta][sup 1](E)-L)][sup +], Cp = C[sub 5]H[sub 5], L = thiophene (T), 2-methylthiophene (2-MeT), 2,5-dimethylthiophene (2,5-Me[sub 2]T), benzo[b]thiophene (BT), 3-methylbenzo[b]thiophene (3-MeBT), selenophene (Sel), 2-methylselenophene (2-MeSel), and 2,5-dimethylselenophene (2,5-Me[sub 2]Sel) are prepared by the reaction of [Cp(NO)(PPh[sub 3])Re(ClC[sub 6]H[sub 5])][sup +] with the appropriate ligand. The T, 2-MeT, BT, 3-MeBT, Sel, 2-MeSel complexes are deprotonated at C(2) by strong, non-nucleophilic bases to give the neutral Cp(NO)(PPh[sub 3])Re(2-L-yl) complexes, where 2-L-yl = 2-thienyl (2-Tyl), 2-5(methylthienyl) (2-(5-MeTyl), 2[minus]benzothienyl (2-BTyl), 2-(3-methylbenzothienyl) (2-3-MeBTyl)), 2-selenyl (2-Selyl), and 2-(5-methylselenyl) (2-5-MeSelyl). The pK[sub a] of the base required to effect this deprotonation increases with the L ligand in the complex in the following order: Sel < T < BT. The 2-Tyl, 2-BTyl and 2-Selyl complexes react with either HBF[sub 4][center dot]Et[sub 2]O or HO[sub 3]SCF[sub 3] at [minus]42[degrees]C to give the corresponding carbene complexes [Cp(NO)(PPh[sub 3])Re(2-L-ylcarbene)][sup +] resulting from protonation at C(3). 43 refs., 2 figs., 5 tabs.

  17. Clinical experience with technetium-99m teboroxime, a neutral, lipophilic myocardial perfusion imaging agent

    SciTech Connect

    Johnson, L.L.; Seldin, D.W. )


    Technetium-99m (Tc-99m) teboroxime is a new technetium-based myocardial perfusion imaging agent (investigational code = SQ30217 (Cardiotec, Squibb Diagnostics)). A member of a class of neutral, lipophilic, technetium-containing complexes known as boronic acid adducts of technetium dioxime (BATO) complexes, this agent is chemically very different from the cationic tracer thallium-201 (Tl-201) and from the cationic technetium complex Tc-99m sestamibi (Cardiolite, Du Pont Imaging Agents). Tc-99m teboroxime has high myocardial extraction, rapid blood clearance, little lung uptake and rapid myocardial washout. A biexponential pattern of myocardial washout is demonstrated in animals and in man. Effective half-lives of the 2 washout components in man are 5.2 minutes and 3.8 hours and represent approximately 66 and 33% of the myocardial activity, respectively. The first half-life for the myocardium is approximately 11 minutes. As the agent washes out of the heart, hepatic uptake occurs, peaking at about 5 minutes after injection. The liver is the major organ of excretion and receives, along with the large bowel, the largest radiation dose. Rapid imaging protocols using standard cameras have achieved good myocardial counts from 3 planar views acquired over a 4- to 5-minute period or for single photon emission computed tomography (SPECT) images acquired over a 10-minute period. An entire stress/rest procedure can be completed in 1 hour. Analysis of data from 155 patients from 4 centers using planar or SPECT imaging showed a sensitivity and specificity for blinded readings of 82 and 91%, respectively, when compared against overall clinical impression. 13 references.

  18. Some aspects of the atmospheric corrosion of copper in the presence of sodium chloride

    SciTech Connect

    Strandberg, H.; Johansson, L.G.


    The effect of NaCl in combination with O{sub 3} and SO{sub 2} on the atmospheric corrosion of copper was investigated. Corrosion products formed after 4 weeks exposure were characterized qualitatively by X-ray diffraction and quantitatively by gravimetry and ion chromatography of leaching solutions. Studies of SO{sub 2} deposition and O{sub 3} consumption were performed using on-line gas analysis. Large amounts of cuprite (Cu{sub 2}O) formed in all environments at 70 and 90% relative humidity. The corrosive effect of salt was strong in pure humid air and in air containing O{sub 3} or SO{sub 2}. Corrosion rate was correlated to the amount of chloride applied to the surface and to humidity. In an atmosphere containing a combination of SO{sub 2} and O{sub 3} at 90% relative humidity, corrosion was rapid in the absence of NaCl. In this case, small additions of NaCl resulted in a marked decrease in corrosion rate. In the absence of SO{sub 2}, tenorite (CuO), nantokite (CuCl), clinoatacamite [Cu{sub 2}(OH){sub 3}Cl], and malachite [Cu{sub 2}(OH){sub 2}CO{sub 3}] were identified. In the presence of SO{sub 2}, brochantite [Cu{sub 4}(OH){sub 6}SO{sub 4}], soluble sulfate, and an unknown phase occurred, while no tenorite or malachite was formed. The combination of SO{sub 2} and O{sub 3} resulted in the formation of antlerite [Cu{sub 3}(OH){sub 4}SO{sub 4}] and Cu{sub 2.5}(OH){sub 3}SO{sub 4}{center_dot}2H{sub 2}O as well.

  19. Investigation of sulfur-bearing minerals in raw and processed oil shale

    SciTech Connect

    Mason, G.M.


    Raw oil shale samples were investigated to provide baseline information on sulfur-bearing mineral composition. The sulfur-bearing mineral identified in raw oil in this study was primarily pyrite (FeS{sub 2}). Sulfur-bearing alteration minerals were gypsum (CaSO{sub 4}{center dot}2H{sub 2}O) and copiapite (Fe{sub 14}O{sub 3}(SO{sub 4}){sub 18}{center dot}63H{sub 2}O), which appeared as crystalline masses on the surfaces of sulfide minerals. Investigation of spent (or processed) oil shale demonstrated that heat-induced mineralogical reactions can drastically alter the crystalline structure of materials. Hexagonal pyrrhotite is the kinetically and structurally preferred sulfur-bearing mineral formed during oil shale processing. The Ca-monosulfide oldhamite was identified in processed Green River Formation oil shale resulting from WRI's TREE process. Oldhamite which has not been identified in terrestrial rocks, formed as a result of high sulfur gases present during the thermal processing of a Ca-rich oil shale. This work provided information concerning (1) thermal alteration of pyrite to pyrrhotite (and pyrrhotite-type minerals) and (2) the disclosure of a mineral not previously reported in oil shale. It is essential for processing and disposal considerations that metastable and unstable mineral forms be identified and more completely understood. Information concerning processing characteristics and sulfur-bearing mineral forms in raw and processed oil shale can be incorporated into the future strategies of solid waste management for fossil fuels. 56 refs., 21 figs., 3 tabs.

  20. Technetium bis(. mu. -oxo) dimers of 1,4,7-triazacyclononane-N,N prime N, double prime -triacetate (TCTA). Synthesis and characterization of (TCTA)Tc(. mu. -O) sub 2 Tc(TCTA) sup n- (n = 2,3) and the crystal structure of Ba sub 2 (TCTA)Tc(. mu. -O) sub 2 Tc(TCTA)(ClO sub 4 )ter dot 9H sub 2 O

    SciTech Connect

    Linder, K.E.; Dewan, J.C.; Davison, A. )


    The mixed-valence technetium(III/IV) bis({mu}-oxo) dimer ((TCTA)Tc({mu}-O){sub 2}Tc(TCTA)){sup 3{minus}} (1; TCTA = 1,4,7-triazayclononane-N,N{prime},N{double prime}-triacetate) has been prepared as its sodium and barium salts. This complex undergoes a reversible on-electron oxidation with potassium persulfate to form ((TCTA)Tc({mu}-O){sub 2}Tc(TCTA)){sup 2{minus}} (2). Both complexes have been characterized by elemental analysis, infrared, UV/visible, and resonance Raman spectroscopy, and fast atom bombardment mass spectrometry. A crystal structure analysis of the Tc(III/IV) dimeter Ba{sub 2}((TCTA)Tc({mu}O){sub 2}Tc(TCTA))(ClO{sub 4}){center dot}9H{sub 2}O (1c) reveals that the two Tc atoms are linked by a planar Tc({mu}-O){sub 2}Tc ring. One TCTA ligand binds to each Tc through an N{sub 3}O donor set, and one of the acetate groups from each ligand bridges the two metal atoms. Resonance Raman spectra of complexes 1 and 2 were obtained by irradiation at 514.5 nm; strong bands assigned to the four-membered Tc({mu}-O){sub 2}Tc ring and the metal-metal multiple bond were seen. The aqueous electrochemistry of the compounds confirms that they are related by a reversible one-electron wave. The Tc(III/IV) dimer 1 represents the first fully characterized Tc-(amino carboxylate) complex in an oxidation state lower than +4. Evidence for the existence of other Tc(III/IV) bis({mu}-oxo) dimers of this type with amino carboxylate ligands such as EDTA and NTA is presented. 23 refs., 3 figs., 4 tabs.

  1. Modeling Spitzer Observations of VV Ser. II. An Extended Quantum-heated Nebula and a Disk Shadow

    NASA Astrophysics Data System (ADS)

    Pontoppidan, Klaus M.; Dullemond, Cornelis P.; Blake, Geoffrey A.; Evans, Neal J., II; Geers, Vincent C.; Harvey, Paul M.; Spiesman, William


    We present mid-infrared Spitzer IRAC and MIPS images of the UX Orionis star VV Ser and the surrounding cloud. The 5.6-70 μm images show bright, localized, and nebulous emission extended over 4' centered on VV Ser. This nebulosity is due to transiently heated grains excited by UV photons emitted by VV Ser. Imprinted on the nebulosity is a wedge-shaped dark band, centered on the star. We interpret this as the shadow cast by the inner regions of a near-edge-on disk, allowing the PAHs to be excited only outside of this shadow. We extend an axisymmetric radiative transfer model of the VV Ser disk described in a companion paper to include quantum-heated PAH molecules and very small grains (VSGs) in the thermal cooling approximation. The presence of a disk shadow strongly constrains the inclination as well as the position angle of the disk. The nebulosity at 5.6-8.0 μm and the 2175 Å absorption feature seen in an archival spectrum from the IUE can be fit using only PAHs, consistent with the main carrier of the 2175 Å feature being due to the graphite-like structure of the PAHs. The PAH component is found to be relatively smoothly distributed in the cloud, while the population of VSGs emitting at 20-70 μm is strongly concentrated ~50'' to the southeast of VV Ser. Depending on the adopted PAH opacity, the abundance of PAHs in the surrounding cloud is constrained to 5%+/-2% of the total dust mass. Although relatively rare, quantum-heated nebulosities surrounding single, well-defined stars are well-suited for gaining unique insights into the physics of very small particles in molecular clouds.

  2. Documentation of chemotherapy infusion preparation costs in academic- and community-based oncology practices.


    Brixner, Diana I; Oderda, Gary M; Nickman, Nancy A; Beveridge, Roy; Jorgenson, James A


    Significant changes in Medicare reimbursement for outpatient oncology services were proposed as part of the Medicare Modernization Act of 2003. The purpose of this study was to identify the "true cost" associated with drug-related handling for the preparation and delivery of chemotherapy doses to estimate the impact of changing reimbursement schema by Medicare. Two academic medical outpatient infusion centers and 2 community cancer centers provided data used to estimate all costs (excluding drug cost) associated with the preparation of chemotherapy doses. The data included both fixed costs (drug storage, space, equipment, and information resources) and variable costs (insurance management, inventory, waste management, pharmacy staff payroll, supplies, and shipping). The average cost for the preparation of chemotherapy doses across all sites was dollar 34.27 (range, dollar 32.08-dollar 41.23). A time-and-motion study was also performed to determine what tasks were conducted by pharmacy staff and how much time was spent in the preparation of the top 15 chemotherapeutic drugs and regimens used in the 4 sites. Data from the 4 centers was projected to show that if 3,990,495 million chemotherapy infusions were administered to a national Medicare population in 2003, when multiplied by the average cost of preparation for infusions determined by the current study (dollar 34.27), the estimated total annual cost to Medicare for chemotherapy preparation by pharmacists is dollar 136,754,263.65. The pharmacists spent most of their days (90% or more) performing tasks directly related to the preparation of these agents. These data provide scientific support for the consideration of appropriate reimbursement for chemotherapy services provided by pharmacists to Medicare beneficiaries. PMID:16507268

  3. High Resolution Imaging of Io's Volcanoes with LBTI

    NASA Astrophysics Data System (ADS)

    Conrad, Al; Leisenring, Jarron; de Kleer, Katherine; Skemer, Andy; Hinz, Philip; Skrutskie, Michael; Veillet, Christian; de Pater, Imke; Bertero, Mario; Boccacci, Patrizia; Defrère, Denis; Hofmann, Karl-Heinz; La Camera, Andrea; Schertl, Dieter; Spencer, John; Weigelt, Gerd; Woodward, Charles E.


    The Large Binocular Telescope (LBT), located on Mount Graham in eastern Arizona, employs two 8.4 meter mirrors with a 14.4 center-to-center separation on a common mount. Coherent combination of these two AO-corrected apertures via the LBT Interferometer (LBTI) produces Fizeau interferometric images with spatial resolution consistent with the diffraction limit of the 22.8-meter aperture. In particular LBTI resolves thermal signatures (i.e., features observed at M-band) on the surface of Io down to ~150 kilometers; a two-fold improvement over what has previously been possible from the ground. We show images collected with LBTI on December 24, 2013, in which Loki's shape is clearly resolved and at least fourteen additional volcanic hot spots are detected.We analyze three locations in the LBTI data: emission features within Loki Patera, the area near Rarog and Heno Patarae, and a hot spot seen in the Colchis Regio.For Loki Patera, we interpret spatially resolved variation in the emission within that region. With M-band resolution that is comparable to what has previously been achievable only at K-band, we compare localized emission features with what has been seen in earlier observations at shorter wavelengths.Thermal emission from activity at Rarog and Heno Patarae is well resolved in these images, while a third hot-spot in the nearby Lerna Regio is also clearly resolved. This area is of special interest since it was the site of two high-effusion outbursts on August 15th, 2013 [de Pater et al. (2014) Icarus].Lastly, we explore a hot-spot seen in the Colchis Regio that may be a remnant of a violent outburst detected on August 29th, 2013 [de Kleer et al. (2014) Icarus].

  4. Identification of the Dinuclear and Tetranuclear Air-Oxidized Products Derived from Labile Phenolate-Bridged Dimanganese(II) Pyridyl-Chelate Compounds

    SciTech Connect

    Larsen,F.; Boisen, A.; Berry, K.; Moubaraki, B.; Murray, K.; McKee, V.; Scarrow, R.; McKenzie, C.


    Dioxygen-sensitive dinuclear manganese complexes of the phenoxo-hinged dinucleating ligand 2,6-bis{l_brace}[N,N{prime}-bis(2-picolyl)amino]methyl{r_brace}-4-tert-butylphenolato (bpbp{sup -}) containing exogenous labile THF, water and perchlorato ligands are described. The manganese(II) complexes [Mn{sub 2}(bpbp)(ClO{sub 4}){sub 2}(THF)]{sup +} (1) and [Mn{sub 2}(bpbp)(ClO{sub 4})(H{sub 2}O){sub 2}]{sup 2+} (2) have been isolated as the salts 1{center_dot}ClO{sub 4}{center_dot}THF{center_dot}3H{sub 2}O, 1{center_dot}B(C{sub 6}H{sub 5}){sub 4}{center_dot}4THF and 2{center_dot}(ClO{sub 4})2{center_dot}H{sub 2}O. Complexes 1 and 2 are spontaneously oxidised in air in solution and the solid state. The reaction products of the air oxidation in THF, water and methanol solutions are labile dinuclear Mn{sup II}-Mn{sup III}, Mn{sup III}{sub 2} and Mn{sup III}-Mn{sup IV} complexes containing water- and methanol-derived exogenous ligands. In addition, a Mn{sub 4} complex has been isolated. Magnetic susceptibility data confirm the Mn{sup II}-Mn{sup III} oxidation state assignment with an S = 2/S = 5/2 model with weak antiferromagnetic coupling (J = -3.7 cm{sup -1}) in [Mn{sub 2}(bpbp)(CH{sub 3}O){sub 2}(H{sub 2}O){sub 2}](ClO{sub 4}){sub 2} [3{center_dot}(ClO{sub 4}){sub 2}]. A tetranuclear complex, [Mn{sub 4}(O){sub 4-n}(OH){sub n}(bpbp){sub 2}](ClO{sub 4}){sub 4} [n = 1 or 2; 7{center_dot}(ClO{sub 4}){sub 4}], recovered from THF shows a Mn{sub 4}O{sub 6} adamantane-type core with the O bridges furnished by the two phenolato groups and four hydroxide/oxide bridges. We have arrived at two feasible formulations for the core metal oxidation states and oxo-bridge protonation states, namely [Mn{sup III}{sub 4}(O){sub 2}(OH){sub 2}(bpbp){sub 2}]{sup 4+} and [Mn{sup III}{sub 3}Mn{sup IV}(O){sub 3}(OH)(bpbp){sub 2}]{sup 4+}, for 7, on the basis of a bond valence sum analysis of the crystal structure, elemental analysis and XANES. Thus, complex 7 is at least two oxidation state levels

  5. Step-by-step assembly of 4d-4f-3d complex based on heptamolybdate anion

    SciTech Connect

    Wu, Shuting; Deng, Binbin; Jiang, Xiuling; Li, Ronghua; Guo, Jiangbin; Lai, Fulong; Huang, Xihe; Huang, Changcang


    Four new complexes, (NH{sub 4}){sub 11.9}[Ln{sub 4.7}(MoO{sub 4})(H{sub 2}O){sub 23}(Mo{sub 7}O{sub 24}){sub 4}]{center_dot}xH{sub 2}O (Ln=Pr, x=34 (1); Ln=Nd, x=19 (2)), [NH{sub 4}]{sub 28}[Ce{sub 8}(MoO{sub 4}){sub 2}(H{sub 2}O){sub 31}(Mo{sub 7}O{sub 24}){sub 8}]{center_dot}74H{sub 2}O (3), and (NH{sub 4}){sub 26}[CoPr{sub 8}(MoO{sub 4}){sub 2}(H{sub 2}O){sub 33}(Mo{sub 7}O{sub 24}){sub 8}]{center_dot}54H{sub 2}O (4) have been synthesized and characterized by single-crystal and powder X-ray diffraction, CHN elemental analyses TGA analyses, IR and UV-Vis spectroscopy. Complex 1-3 are 0D compounds constructed by the connection between Ln{sup III} ions and [Mo{sub 7}O{sub 24}]{sup 6-} unit. In complex 4, the existence of Co{sup II} connects the polyanion clusters into 1D chain. The introduction of 3d metal (cobalt cation) and 4f metal (Ln=Pr{sup III}, Nd{sup III}, Ce{sup III}) encourages the coordination capability for [Mo{sub 7}O{sub 24}]{sup 6-} unit, which shows interesting coordination modes. The [Mo{sub 7}O{sub 24}]{sup 6-} unit in 1-4 shows three new coordination modes, connecting up to four metal cations. Complexes 1-4 show antiferromagnetic behavior via variable temperature magnetic study. The photoluminescence spectrum indicates the photoluminescence property for 4. - Graphical abstract: Heptamolybdate anion shows extraordinary coordination geometry in the presence of both lanthanide cation (Pr{sup III}) and transitional metal cation (Co{sup II}), which give rise to a new 4d-4f-3d complex. Black-Small-Square Highlights: Black-Right-Pointing-Pointer A new 4d-4f-3d complex that containing 1D chain was obtained and discussed. Black-Right-Pointing-Pointer New coordination geometry with higher coordination number of heptamolybdate. Black-Right-Pointing-Pointer Series of heptamolybdate contained complexes were synthesized and characterized. Black-Right-Pointing-Pointer Complexes mentioned above show antiferromagnetic behavior.

  6. Barium uranyl diphosphonates

    SciTech Connect

    Nelson, Anna-Gay D.; Alekseev, Evgeny V.; Ewing, Rodney C.; Albrecht-Schmitt, Thomas E.


    Three Ba{sup 2+}/UO{sub 2}{sup 2+} methylenediphosphonates have been prepared from mild hydrothermal treatment of uranium trioxide, methylendiphosphonic acid (C1P2) with barium hydroxide octahydrate, barium iodate monohydrate, and small aliquots of HF at 200 Degree-Sign C. These compounds, Ba[UO{sub 2}[CH{sub 2}(PO{sub 3}){sub 2}]{center_dot}1.4H{sub 2}O (Ba-1), Ba{sub 3}[(UO{sub 2}){sub 4}(CH{sub 2}(PO{sub 3}){sub 2}){sub 2}F{sub 6}]{center_dot}6H{sub 2}O (Ba-2), and Ba{sub 2}[(UO{sub 2}){sub 2}(CH{sub 2}(PO{sub 3}){sub 2})F{sub 4}]{center_dot}5.75H{sub 2}O (Ba-3) all adopt layered structures based upon linear uranyl groups and disphosphonate molecules. Ba-2 and Ba-3 are similar in that they both have UO{sub 5}F{sub 2} pentagonal bipyramids that are bridged and chelated by the diphosphonate moiety into a two-dimensional zigzag anionic sheet (Ba-2) and a one-dimensional ribbon anionic chain (Ba-3). Ba-1, has a single crystallographically unique uranium metal center where the C1P2 ligand solely bridges to form [UO{sub 2}[CH{sub 2}(PO{sub 3}){sub 2}]{sup 2-} sheets. The interlayer space of the structures is occupied by Ba{sup 2+}, which, along with the fluoride ion, mediates the structure formed and maintains overall charge balance. - Graphical abstract: Illustration of the stacking of the layers in Ba{sub 3}[(UO{sub 2}){sub 4}(CH{sub 2}(PO{sub 3}){sub 2}){sub 2})F{sub 6}]{center_dot}6H{sub 2}O viewed along the c-axis. The structure is constructed from UO{sub 7} pentagonal bipyramidal units, U(1)O{sub 7}=gray, U(2)O{sub 7}=yellow, barium=blue, phosphorus=magenta, fluorine=green, oxygen=red, carbon=black, and hydrogen=light peach. Highlights: Black-Right-Pointing-Pointer The polymerization of the UO{sub 2}{sup 2+} sites to form uranyl dimers leads to structural variations in compounds. Black-Right-Pointing-Pointer Barium cations stitch uranyl diphosphonate anionic layers together, and help mediate structure formation. Black-Right-Pointing-Pointer HF acts as both a

  7. Hydrothermal syntheses, structures and characterizations of two luminescent cadmium(II) complexes with p-xylenediphosphonic acid and N-donor ligands

    SciTech Connect

    Sun Yanqiong; Hu Jin; Zhang Hanhui; Chen Yiping


    Two novel cadmium diphosphonates [Cd(cis-H{sub 4}BDPP)(2,2 Prime -bipy){sub 2}]{center_dot}(trans-H{sub 2}BDPP)]{sub n} (1) and [Cd(trans-H{sub 2}BDPP)(phen)]{sub n} (2) (H{sub 4}BDPP=p-xylenediphosphonic acid, phen=1,10-phenanthroline, 2,2 Prime -bipy=2,2 Prime -bipyridine) were hydrothermally synthesized from p-xylenediphosphonic acid and CdSO{sub 4}{center_dot}3H{sub 2}O with phen or 2,2 Prime -bipy as second ligand components and characterized by means of elemental analyses, IR, TG analysis, luminescence spectroscopy and single crystal X-ray diffraction. Compound 1 consists of a novel one-dimensional (1D) sinusoidal [Cd(cis-H{sub 4}BDPP)(2,2 Prime -bipy){sub 2}] chains and trans-H{sub 2}BDPP anions. Compound 2 possesses a three-dimensional architecture built from double zigzag -Cd-O-P-O-Cd- chains pillared by trans-p-xylylenediphosphonate ligands from four different directions. There are hexagonal channels running along the c-axis and the coordinated phen ligands suspend in the hexagonal channels. The results indicate that p-xylenediphosphonic acid can adopt varied coordination modes and conformations in the formation of the complexes and the influence of the N-donor ligands on the structure of the complexes is discussed. - Graphical abstract: Two new cadmium diphosphonates were obtained by using two different auxiliary ligands. The influence of the N-donor ligands on the structure of the complexes is discussed. Highlights: Black-Right-Pointing-Pointer The first example of cadmium(II)-p-xylenediphosphonates templated by second ligand. Black-Right-Pointing-Pointer The role of size of the auxiliary ligand on the structure of cadmium p-xylenediphosphonates. Black-Right-Pointing-Pointer The cis and trans configurations of p-xylenediphosphonates exist in the same crystal structure. Black-Right-Pointing-Pointer Three-dimensional 4-connected framework with PtS network topology.

  8. Optical and TDPAC spectroscopy of Hg(II)-rubredoxin: model for a mononuclear tetrahedral [Hg(CysS)4]2- center. ISOLDE Collaboration.


    Faller, P; Ctortecka, B; Tröger, W; Butz, T; Vasák, M


    Rubredoxins possess a well-defined mononuclear tetrahedral tetrathiolate metal binding site, a feature exploited by several investigations to study the spectroscopic characteristics and the coordination chemistry of different metal ions at this binding site. In the present work, Hg(II)-substituted rubredoxin (Rd) from Desulfovibrio gigas has been studied by electronic absorption, circular dichroism (CD), magnetic circular dichroism (MCD), and time differential perturbed angular correlation of gamma-rays (TDPAC) spectroscopies. The TDPAC spectrum of 199mHg-Rd at pH 8 exhibits a prevailing nuclear quadrupole interaction (NQI) with a precession frequency of omega1=0.09 Grad/s and an asymmetry parameter eta=0, features characteristic of a slightly distorted tetrahedral tetrathiolate metal coordination, i.e, a HgCysS4 center. In addition, three minor populated NQIs have also been detected. They may represent a trigonal HgS3 (omega1=1.13 Grad/s, eta=0.21), a digonal HgS2 (omega1= 1.34 Grad/s, eta =0.20), and a digonal Hg(II) coordination (omega = 1.58 Grad/s, eta =0.18) with unidentified ligands. Since similar studies at pH 2.5 revealed a time-dependent increase of the HgCysS4 population, the low populated sites may represent intermediate Hg(II) complexes formed prior to the generation of the thermodynamically stable structure. The metal-induced absorption envelope of Hg-Rd reveals three distinct transitions with Gaussian-resolved maxima located at 230, 257, and 284 nm, which are paralleled by dichroic features in the corresponding difference CD spectrum of Hg(II)-Rd versus apo-Rd. Based on the optical electronegativity theory of J*rgensen, the lowest energy transition has been attributed to a CysS-Hg(II) charge-transfer excitation. The Td type of metal coordination in Hg-Rd is supported by the presence of an unresolved A-term with a negative lobe at 295 nm in the difference MCD spectrum. These results point to the usefulness of optical and TDPAC spectroscopies for

  9. The fate of particle-reactive radionuclides on the Amazon and Yangtze continental shelves

    SciTech Connect

    McKee, B.A.


    Water column and seabed samples collected from the continental shelves adjacent to the Yangtze and Amazon Rivers were analyzed for particle-reactive radionuclides ({sup 234}Th, {sup 228}Th, {sup 210}Pb), and their respective parent nuclides ({sup 238}U, {sup 228}Ra, {sup 226}Ra). On the Amazon shelf, dissolved {sup 238}U activities increase with increasing salinity to a shelf maximum (4.6 dpm 1{sup {minus}1}) that is much higher than the open-ocean value (2.5 dpm 1{sup {minus}1}) because uranium is desorbed from the ferric-oxyhydroxide coatings of bottom sediments and advected into the overlying water column during periodic resuspension events. As a result, measurement of only the riverine flux of dissolved {sup 238}U underestimates (by a factor of 5) the flux of dissolved uranium from the Amazon shelf to the open ocean. K{sub e} values decrease with increased SSC and range from 10{sup 5}{center dot}10{sup 6} ml g{sup {minus}1} for Th and from 10{sup 4}{center dot}10{sup 6} ml g{sup {minus}1} for Po and Pb. The approach to equilibrium can best be described as a two-step process that is initially rapid (rate constants: 10-100 d{sup {minus}1}, during the first 30 minutes), but becomes less rapid (rate constants: 1-4 d{sup {minus}1}) as equilibrium is attained. Distribution coefficients for {sup 234}Th, {sup 228}Th and {sup 210}Pb exhibit large spatial variability on the Amazon shelf (range: 10{sup 3} - 10{sup 6} ml g{sup {minus}1}) and on the Yangtze shelf (range: 10{sup 4} - 10{sup 6} ml g{sup {minus}1}). On the Amazon shelf, particle residence time is short (2-3 hours) relative to scavenging residence time (15-20 hours) therefore, only 1-31% of equilibrium between dissolved and particulate thorium is attained. On the Yangtze shelf, particle residence time is long (12-89 hours) relative to scavenging time (2-23 hours) resulting in K{sub d} values near (97-100%) equilibrium.

  10. Syntheses, structures and photoelectric properties of a series of Cd(II)/Zn(II) coordination polymers and coordination supramolecules

    SciTech Connect

    Jin Jing; Han Xiao; Meng Qin; Li Dan; Chi Yuxian; Niu Shuyun


    Five Cd(II)/Zn(II) complexes [Cd(1,2-bdc)(pz){sub 2}(H{sub 2}O)]{sub n} (1), [Cd1Cd2(btec)(H{sub 2}O){sub 6}]{sub n} (2), [Cd(3,4-pdc) (H{sub 2}O)]{sub n} (3), [Zn(2,5-pdc)(H{sub 2}O){sub 4}]{center_dot}2H{sub 2}O (4) and {l_brace} [Zn(2,5-pdc)(H{sub 2}O){sub 2}]{center_dot}H{sub 2}O{r_brace} {sub n} (5) (H{sub 2}bdc=1,2-benzenedicarboxylic acid, pz=pyrazole, H{sub 4}btec=1,2,4,5-benzenetetracarboxylic acid, H{sub 2}pdc=pyridine-dicarboxylic acid) were hydrothermally synthesized and characterized by single-crystal X-ray diffraction, surface photovoltage spectroscopy, XRD, TG analysis, IR and UV-vis spectra and elemental analysis. Structural analyses show that complexes 1-3 are 1D, 2D and 3D Cd(II) coordination polymers, respectively. Complex 4 is a mononuclear Zn(II) complex. Complex 5 is a 3D Zn(II) coordination polymer. The surface photoelectric properties of complexes were investigated by SPS. The results indicate that all complexes exhibit photoelectric responses in the range of 300-600 nm, which reveals that they all possess certain photoelectric conversion properties. By the comparative analyses, it can be found that the species and coordination micro-environment of central metal ion, the species and property of ligands affect the intensity and scope of photoelectric response. - Graphical abstract: Five Cd(II)/Zn(II) complexes have been hydrothermally synthesized and characterized. The photoelectric properties were studied with SPS. The species and coordination micro-environment of central metal ion, the species and property of ligands all affect the photoelectric responses. Highlights: Black-Right-Pointing-Pointer Five Cd/Zn complexes have been synthesized and characterized. Black-Right-Pointing-Pointer The SPS results indicate they possess obvious photoelectric conversion property. Black-Right-Pointing-Pointer The species and coordination environment of central metal ion affect SPS. Black-Right-Pointing-Pointer The species and property of ligands affect SPS

  11. Versatility of Y-family Sulfolobus solfataricus DNA Polymerase Dpo4 in Translesion Synthesis Past Bulky N[superscript 2]-Alkylguanine Adducts

    SciTech Connect

    Zhang, Huidong; Eoff, Robert L.; Kozekov, Ivan D.; Rizzo, Carmelo J.; Egli, Martin; Guengerich, F. Peter


    In contrast to replicative DNA polymerases, Sulfolobus solfataricus Dpo4 showed a limited decrease in catalytic efficiency (k{sub cat}/K{sub m}) for insertion of dCTP opposite a series of N{sup 2}-alkylguanine templates of increasing size from (methyl (Me) to (9-anthracenyl)-Me (Anth)). Fidelity was maintained with increasing size up to (2-naphthyl)-Me (Naph). The catalytic efficiency increased slightly going from the N{sup 2}-NaphG to the N{sup 2}-AnthG substrate, at the cost of fidelity. Pre-steady-state kinetic bursts were observed for dCTP incorporation throughout the series (N{sup 2}-MeG to N{sup 2}-AnthG), with a decrease in the burst amplitude and k{sub pol}, the rate of single-turnover incorporation. The pre-steady-state kinetic courses with G and all of the six N{sup 2}-alkyl G adducts could be fit to a general DNA polymerase scheme to which was added an inactive complex in equilibrium with the active ternary Dpo4 {center_dot} DNA {center_dot} dNTP complex, and only the rates of equilibrium with the inactive complex and phosphodiester bond formation were altered. Two crystal structures of Dpo4 with a template N{sup 2}-NaphG (in a post-insertion register opposite a 3'-terminal C in the primer) were solved. One showed N{sup 2}-NaphG in a syn conformation, with the naphthyl group located between the template and the Dpo4 'little finger' domain. The Hoogsteen face was within hydrogen bonding distance of the N4 atoms of the cytosine opposite N{sup 2}-NaphG and the cytosine at the -2 position. The second structure showed N{sup 2}-Naph G in an anti conformation with the primer terminus largely disordered. Collectively these results explain the versatility of Dpo4 in bypassing bulky G lesions.

  12. Synthesis, characterization, and reactivity of sulfided hexanuclear molybdenum cluster compounds

    SciTech Connect

    Spink, D.


    Hexanuclear molybdenum clusters with mixed chloride and sulfide bridging ligands were prepared by reacting {alpha}-MoCl{sub 2} with sodium hydrosulfide in the presence of sodium butoxide. The resulting species, Mo{sub 6}Cl{sub (8-x)}S{sub x}{center dot}npy(x {congruent} 3.6, n {congruent} 4, py = pyridine), was pyrophoric and insoluble. The mixed sulfide chloride cluster species Mo{sub 6}S{sub 4}Cl{sub 4}{center dot}6OPEt{sub 3} and Mo{sub 6}S{sub {approximately}5}Cl{sub {approximately}3}{center dot}6PEt{sub 3} and Mo{sub 6}S{sub 8}{center dot}6PEt{sub 3} were isolated and characterized. Phosphorus-31 nuclear magnetic resonance, electron paramagnetic resonance, and UV/visible spectra were obtained for each fraction. The completely sulfided cluster, Mo{sub 6}S{sub 8}{center dot}6PEt{sub 3}, was prepared similarly and used in various experiments as a possible precursor to Chevrel phase materials of the type Mo{sub 6}S{sub 8}or M{sub n}Mo{sub 6}S{sub 8}. With the goal of removing all of the triethylphosphine ligands, Mo{sub 6}S{sub 8}{center dot}6PEt{sub 3} was reacted with the transition metal carbonyls molybdenum hexacarbonyl and dicobalt octacarbonyl. Reaction on the molecular sulfide cluster with copper(I) chloride in toluene gave a completely insoluble product. The reaction of Mo{sub 6}S{sub 8}{center dot}6PEt{sub 3} with propylene sulfide gave a product whose infrared spectra showed only very weak peaks associated with coordinated triethylphosphine. The elemental analysis of this product fit the formula Mo{sub 6}S{sub 8}{center dot}5SPEt{sub 3}. Reactivity of the outer ligands of the Mo{sub 6}S{sub 8}{center dot}npy and Mo{sub 6}S{sub 8}{center dot}(6{minus}x)PrNH{sub x} clusters were investigated. Crystalline Mo{sub 6}S{sub 8}{center dot}6THT was recovered from the reaction of the n-propylamine derivative with THT. A crystal structure determination was done. 87 refs., 12 fig., 15 tabs.

  13. Current practice in diagnosis and treatment of acute graft-versus-host disease: results from a survey among German-Austrian-Swiss hematopoietic stem cell transplant centers.


    Wolff, Daniel; Ayuk, Francis; Elmaagacli, Ahmet; Bertz, Hartmut; Lawitschka, Anita; Schleuning, Michael; Meyer, Ralf-Georg; Gerbitz, Armin; Hilgendorf, Inken; Hildebrandt, Gerhard C; Edinger, Matthias; Klein, Stephan; Halter, Jörg; Mousset, Sabine; Holler, Ernst; Greinix, Hildegard T


    To assess current clinical practice in diagnosis and treatment of acute graft-versus-host disease (aGVHD), we performed a survey among German, Austrian, and Swiss allogeneic hematopoietic stem cell transplantation (allo-HSCT) centers. Thirty-four of 72 contacted centers (47%) completed both the diagnostic and therapeutic sections of the survey, representing 65% of allo-HSCT activity within the participating countries in 2011. Three pediatric centers answered as requested only the diagnostic part of the survey. In the presence of diarrhea and decreased oral intake after engraftment, only 4 centers (12%) do not perform any endoscopy before the start of immunosuppressive treatment. In case of a skin rash with the differential diagnosis of drug reaction, only 12 centers (35%) perform a skin biopsy up front, whereas 19 do so after failure of systemic steroids. In the presence of rapidly increasing cholestasis occurring without any other signs of aGVHD, 11 centers (32%) perform a liver biopsy up front and 14 only after failure of steroid treatment, whereas 9 centers do not perform a liver biopsy at all. Twenty centers (59%) use a percutaneous approach, 12 a transvenous approach, and 1 mini-laparoscopy for liver biopsies. First-line treatment of cutaneous aGVHD stage 1 consists of topical treatment alone in 17 of 31 responding centers (61%), whereas isolated cutaneous aGVHD stage III is treated with systemic steroids (prednisolone below 0.5 mg/kg/day n = 2, 0.5 to 1.0 mg/kg/day n = 10, above 1.0 to 2.5 mg/kg/day n = 19) without or with topical agents (steroids n = 10; calcineurin inhibitors n = 3). In gastrointestinal manifestations of aGVHD, 9 centers (29%) add topical to systemic steroids, and 3 consider topical steroids as the only treatment for mild gastrointestinal and cutaneous aGVHD. The choice of agent for second-line treatment as well as the sequence of administration are extremely heterogeneous, most likely due to a lack of convincing data published

  14. Manufacture of ammonium sulfate fertilizer from FGD-gypsum. Quarterly report, 1 December 1994--28 February 1995

    SciTech Connect

    Chou, M.I.M.; Rostam-Abadi, M.; Lytle, J.M.; Bruinius, J.A.; Hoeft, R.; Dewey, S.; Achorn, F.


    The overall goal of this project is to assess the technical and economic feasibility for producing feasibility-grade ammonium sulfate from gypsum produced as part of limestone flue gas desulfurization (FGD) processes. This is a cooperative effort among the ISGS, the UIUC, AlliedSignal, SE-ME, Henry Fertilizer, Illinois Power Co. (IP), and Central Illinois Public Services (CIPS). Bench-scale experiments will be conducted to obtain process engineering data for the manufacture of ammonium sulfate from FGD-gypsum and to help evaluate technical and economic feasibility of the process. Controlled greenhouse experiments will be conducted at UIUC to evaluate the chemical impact of coal-derived impurities in ammonium sulfate produced from FGD-gypsum on soil properties. A process flow sheet will be proposed and market demand for the products will be established. An engineering team at IP will provide an independent review of the economics of the process. AlliedSignal will be involved in testing and quality evaluation of ammonium sulfate samples and is interested in an agreement to market the finished product. CIPS will provide technical assistance and samples of FGD -gypsum for the project. In this quarter, with an exception of the neutron activation analysis, analyses of FGD-gypsum samples that were generated by two power stations were completed. The high quality FGD-gypsum sample produced from the Abbott power plant in Champaign, IL was 98.36% gypsum, CaSO{sub 4}{center_dot}2H{sub 2}O, and less than 0.01% calcium`` sulfite, CaSO{sub 3}. The low quality sample from CIPS`s Newton Power Plant at Jasper, Illinois, was only 7.36% of gypsum. It was 87.54% calcium sulfite. A literature search provided the information to set up a batch, bench-scale reactor system. Reactions were conducted at 70{degrees}C for a range of times which resulted in 82% conversion of calcium sulfate to ammonium sulfate.

  15. Acidic soil amendment with a magnesium-containing fluidized bed combustion by-product

    SciTech Connect

    Stehouwer, R.C.; Dick, W.A.; Sutton, P.


    Removal of SO{sub 2} from the emissions of coal-fired boilers produces by-products that often consist of CaSO{sub 4}, residual alkalinity, and coal ash. These by-products could be beneficial to acidic soils because of their alkalinity and the ability of gypsum (CaSO{sub 4}{center{underscore}dot}2H{sub 2}O) to reduce Al toxicity in acidic subsoils. A 3-yr field experiment was conducted to determine the liming efficacy of a fluidized bed combustion boiler by-product (FBC) that contained 129 g Mg kg{sup {minus}1} as CaMg(CO{sub 3}){sub 2} and MgO and its effects on surface and subsurface soil chemistry. The FBC was mixed in the surface 10 cm of two acidic soils (Wooster silt loam, an Oxyaquic Fragiudalf, and Coshocton silt loam, an Aquultic Hapludalf) at rates of 0, 0.5, 1, and 2 times each soil's lime requirement (LR). Soils were sampled in 10-cm increments to depths ranging from 20 to 110 cm, and corn (Zea mays L.) and alfalfa (Medicago sativa L.) were grown. Application of Mg-FBC increased alfalfa yields in all six site-years, whereas it had no effect on corn grain yield in five site-years and decreased grain yield in one site-year. Plant tissue concentrations of Mg, S, and Mo were increased by Mg-FBC, while most trace elements were either unaffected or decreased. Application of Mg-FBC at one or two times LR increased surface soil pH to near 7 within 1 wk. Although surface soil pH remained near 7 for 2 yr, there was minimal effect on subjacent soil pH. Application of Mg-FBC increased surface soil concentrations of Ca, Mg, and S, which promoted downward movement of Mg and SO{sub 4}. This had different effects on subsoil chemistry in the two soils: in the high-Ca-status Wooster subsoil, exchangeable Ca was decreased and exchangeable Al was increased, whereas in the high-Al-status Coshocton subsoil, exchangeable Al was decreased and exchangeable Mg was increased. The Mg-FBC was an effective liming material and, because of the presence of both Mg and SO{sub 4}, may be

  16. Hydrothermal syntheses, crystal structures and luminescence properties of zinc(II) and cadmium(II) coordination polymers based on bifunctional 3,2 Prime :6 Prime ,3 Prime Prime -terpyridine-4 Prime -carboxylic acid

    SciTech Connect

    Li, Na; Guo, Hui-Lin; Hu, Huai-Ming; Song, Juan; Xu, Bing; Yang, Meng-Lin; Dong, Fa-Xin; Xue, Gang-Lin


    Five new coordination polymers, [Zn{sub 2}(ctpy){sub 2}Cl{sub 2}]{sub n} (1), [Zn{sub 2}(ctpy){sub 2}(ox)(H{sub 2}O){sub 2}]{sub n} (2), [Zn{sub 2}(ctpy)(3-btc)(H{sub 2}O)]{sub n}{center_dot}0.5nH{sub 2}O (3), [Cd(ctpy){sub 2}(H{sub 2}O)]{sub n} (4), [Cd{sub 4}(ctpy){sub 2}(2-btc){sub 2}(H{sub 2}O){sub 2}]{sub n}{center_dot}2nH{sub 2}O (5), (Hctpy=3,2 Prime :6 Prime ,3 Prime Prime -terpyridine-4 Prime -carboxylic acid, H{sub 2}ox=oxalic acid, H{sub 3}(3-btc)=1,3,5-benzenetricarboxylic acid, H{sub 3}(2-btc)=1,2,4-benzenetricarboxylic acid) have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. Compounds 1-2 are a one-dimensional chain with weak interactions to form 3D supramolecular structures. Compound 3 is a 4-nodal 3D topology framework comprised of binuclear zinc units and (ctpy){sup -} anions. Compound 4 shows two dimensional net. Compound 5 is a (4,5,6)-connected framework with {l_brace}4{sup 4}{center_dot}6{sup 2}{r_brace}{l_brace}4{sup 6}{center_dot}6{sup 4}{r_brace}{sub 2}{l_brace}4{sup 9}{center_dot}6{sup 6}{r_brace} topology. In addition, the thermal stabilities and photoluminescence properties of 1-5 were also studied in the solid state. - Graphical abstract: Five new Zn/Cd compounds with 3,2 Prime :6 Prime ,3 Prime Prime -terpyridine-4 Prime -carboxylic acid were prepared. The photoluminescence and thermal stabilities properties of 1-5 were investigated in the solid state. Highlights: Black-Right-Pointing-Pointer Five new zinc/cadmium metal-organic frameworks have been hydrothermal synthesized. Black-Right-Pointing-Pointer The structural variation is attributed to the diverse metal ions and auxiliary ligand. Black-Right-Pointing-Pointer Compounds 1-5 exhibit 1D ring chain, 2D layer and 3D open-framework, respectively. Black-Right-Pointing-Pointer These compounds exhibit strong solid state luminescence emission at room temperature.

  17. A series of 2D metal-quinolone complexes: Syntheses, structures, and physical properties

    SciTech Connect

    He, Jiang-Hong; Xiao, Dong-Rong; Chen, Hai-Yan; Sun, Dian-Zhen; Yan, Shi-Wei; Wang, Xin; Ye, Zhong-Li; Luo, Qun-Li; Wang, En-Bo


    Six novel 2D metal-quinolone complexes, namely [Cd(cfH)(bpdc)]{center_dot}H{sub 2}O (1), [M(norfH)(bpdc)]{center_dot}H{sub 2}O (M=Cd (2) and Mn (3)), [Mn{sub 2}(cfH)(odpa)(H{sub 2}O){sub 3}]{center_dot}0.5H{sub 2}O (4), [Co{sub 2}(norfH)(bpta)({mu}{sub 2}-H{sub 2}O)(H{sub 2}O){sub 2}]{center_dot}H{sub 2}O (5) and [Co{sub 3}(saraH){sub 2}(Hbpta){sub 2}(H{sub 2}O){sub 4}]{center_dot}9H{sub 2}O (6) (cfH=ciprofloxacin, norfH=norfloxacin, saraH=sarafloxacin, bpdc=4,4 Prime -biphenyldicarboxylate, odpa=4,4 Prime -oxydiphthalate, bpta=3,3 Prime ,4,4 Prime -biphenyltetracarboxylate) have been synthesized and characterized. Compounds 1-3 consist of 2D arm-shaped layers based on the 1D {l_brace}M(COO){r_brace}{sub n}{sup n+} chains. Compounds 4 and 5 display 2D structures based on tetranuclear manganese or cobalt clusters with (3,6)-connected kgd topology. Compound 6 exhibits a 2D bilayer structure, which represents the first example of metal-quinolone complexes with 2D bilayer structure. By inspection of the structures of 1-6, it is believed that the long aromatic polycarboxylate ligands are important for the formation of 2D metal-quinolone complexes. The magnetic properties of compounds 3-6 was studied, indicating the existence of antiferromagnetic interactions. Furthermore, the luminescent properties of compounds 1-2 are discussed. - Graphical abstract: Six novel 2D metal-quinolone complexes have been prepared by self-assemblies of the quinolones and metal salts in the presence of long aromatic polycarboxylates. Highlights: Black-Right-Pointing-Pointer Compounds 1-3 consist of novel 2D arm-shaped layers based on the 1D {l_brace}M(COO){r_brace}{sub n}{sup n+} chains. Black-Right-Pointing-Pointer Compounds 4 and 5 are two novel 2D layers based on tetranuclear Mn or Co clusters with kgd topology. Black-Right-Pointing-Pointer Compound 6 is the first example of metal-quinolone complexes with 2D bilayer structure. Black-Right-Pointing-Pointer Compounds 1-6 represent six unusual

  18. Intervalence charge transfer luminescence: The anomalous luminescence of cerium-doped Cs{sub 2}LiLuCl{sub 6} elpasolite

    SciTech Connect

    Seijo, Luis; Barandiarán, Zoila


    The existence of intervalence charge transfer (IVCT) luminescence is reported. It is shown that the so called anomalous luminescence of Ce-doped elpasolite Cs{sub 2}LiLuCl{sub 6}, which is characterized mainly by a very large Stokes shift and a very large band width, corresponds to an IVCT emission that takes place in Ce{sup 3+}–Ce{sup 4+} pairs, from the 5de{sub g} orbital of Ce{sup 3+} to 4f orbitals of Ce{sup 4+}. Its Stokes shift is the sum of the large reorganization energies of the Ce{sup 4+} and Ce{sup 3+} centers formed after the fixed-nuclei electron transfer and it is equal to the energy of the IVCT absorption commonly found in mixed-valence compounds, which is predicted to exist in this material and to be slightly larger than 10 000 cm{sup −1}. The large band width is the consequence of the large offset between the minima of the Ce{sup 3+}–Ce{sup 4+} and Ce{sup 4+}–Ce{sup 3+} pairs along the electron transfer reaction coordinate. This offset is approximately 2√(3) times the difference of Ce–Cl equilibrium distances in the Ce{sup 3+} and Ce{sup 4+} centers. It is shown that the energies of the peaks and the widths of IVCT absorption and emission bands can be calculated ab initio with reasonable accuracy from diabatic energy surfaces of the ground and excited states and that these can be obtained, in turn, from independent calculations on the donor and acceptor active centers. We obtained the energies of the Ce{sup 3+} and Ce{sup 4+} active centers of Ce-doped Cs{sub 2}LiLuCl{sub 6} by means of state-of-the-art wave-function-theory spin-orbit coupling relativistic calculations on the donor cluster (CeCl{sub 6}Li{sub 6}Cs{sub 8}){sup 11+} and the acceptor cluster (CeCl{sub 6}Li{sub 6}Cs{sub 8}){sup 12+} embedded in a quantum mechanical embedding potential of the host. The calculations provide interpretations of unexplained experimental observations as due to higher energy IVCT absorptions, and allow to reinterpret others. The existence of

  19. FY04 Engineering Technology Reports Laboratory Directed Research and Development

    SciTech Connect

    Sharpe, R M


    areas. Their LDRD projects are the key resources to attain this competency, and, as such, nearly all of Engineering's portfolio falls under one of the five Centers. The Centers and their Directors are: (1) Center for Computational Engineering: Robert M. Sharpe; (2) Center for Microtechnology and Nanotechnology: Raymond P. Mariella, Jr.; (3) Center for Nondestructive Characterization: Harry E. Martz, Jr.; (4) Center for Precision Engineering: Keith Carlisle; and (5) Center for Complex Distributed Systems: Gregory J. Suski, Acting Director.

  20. The high-pressure-high-temperature behavior of bassanite

    SciTech Connect

    Comodi, Paola; Nazzareni, Sabrina; Dubrovinsky, Leonid; Merlini, Marco


    The pressure evolution of bassanite (CaSO{sub 4} {center_dot} 1/2 H{sub 2}O) was investigated by synchrotron X-ray powder diffraction along three isotherms: at room temperature up to 33 GPa, at 109 C up to 22 GPa, and at 200 C up to 12 GPa. The room-temperature cell-volume data, from 0.001 to 33 GPa, were fitted to a third-order Birch-Murnaghan equation-of-state, and a bulk modulus K{sub 0} = 86(7) GPa with K' = 2.5(3) was obtained. The axial compressibility values are {beta}{sub a} = 3.7(2), {beta}{sub b} = 3.6(1), and {beta}{sub c} = 2.8(1) GPa{sup -1} (x10{sup -3}) showing a slightly anisotropic behavior, with the least compressible direction along c axis. The strain tensor analysis shows that the main deformation occurs in the (010) plane in a direction 18{sup o} from the a axis. The bulk moduli for isotherms 109 and 200 C, were obtained by fitting cell-volume data with a second-order Birch-Murnaghan equation-of-state, with K' fixed at 4, and were found to be K{sub 109} = 79(4) GPa and K{sub 200} = 63(7) GPa, respectively. The axial compressibility values for isotherm 109 C are {beta}{sub a} = 2.4(1), {beta}{sub b} = 3.0(1), {beta}{sub c} = 2.5(1) (x10{sup -3}) GPa{sup -1}, and for isotherm 200 C they are {beta}{sub a} = 3.5(3), {beta}{sub b} = 3.4(3), {beta}{sub c} = 2.6(4) (x10{sup -3}) GPa{sup -1}. These two bulk moduli and the 20 C bulk modulus, K{sub 0,20} = 69(8) recalculated to a second-order Birch-Murnaghan EoS to be consistent, as well as the axial compressibilities, are similar for the three isotherms indicating that the thermal effect on the bulk moduli is not significant up to 200 C. The size variation of the pseudo-hexagonal channel with pressure and temperature indicates that the sulfate 'host' lattice and the H{sub 2}O 'guest' molecule in bassanite do not undergo strong change up to 33 GPa and 200 C.

  1. Luminescence dynamics and {sup 13}C NMR characteristics of dinuclear complexes exhibiting coupled lanthanide(III) cation pairs

    SciTech Connect

    Matthews, K.D.; Bailey-Folkes, S.A.; Kahwa, I.A.


    Luminescence and cross-polarization magic angle spinning (CP-MAS) {sup 13}C NMR properties of lanthanide dinuclear macrocyclic complexes of a compartmental Schiff base chelate (1) derived from the condensation of 2,6-diformyl-p-cresol and 3,6-dioxa-1,8-octanediamine are reported. The Schiff base chromophore in 1 is a strong light absorber and an efficient sensitizer for intense Tb{sup 3+}({sup 5}D{sub 4}) and Eu{sup 3+}({sup 5}D{sub 0})(T < 110 K ) emission which does not exhibit self-quenching effects. Emission from Tb{sup 3+} is sensitized by the ligand singlet state; in striking contrast, Eu{sup 3+} emission is sensitized by the triplet state and reveals an unusual nonradiative quenching process at T > 110 K with a thermal barrier of {approx} 2300 cm{sup {minus}1}. Weak emission is observed from Dy{sup 3+}({sup 4}F{sub 9/2}), Sm{sup 3+}({sup 4}G{sub 5/2}), and Pr{sup 3+}({sup 1}D{sub 2}) diluted in Gd{sup 3+} (i.e., from Gd{sup 3+}-Ln{sup 3+} heteropairs, Ln = Pr, Sm, Dy). Intramolecular metal-metal (Ln-Ln = 4 {Angstrom}) interactions account for the greatly quenched emission from Sm{sup 3+}-Sm{sup 3+} and Dy{sup 3+}-Dy{sup 3+} homopairs compared to Gd{sup 3+}-Ln heteropairs (Ln = Sm, Dy). Gd{sup 3+}-Ln{sup 3+} emission lifetimes at 77 K are 1610 (Tb{sup 3+}), 890 (Eu{sup 3+}), 14 (Dy{sup 3+}) and {approx} 13 {mu}s (Sm{sup 3+}). Nonradiative relaxation processes at 77 K in dilute Ln{sup 3+}:Gd{sub 2}1(NO{sub 3}){sub 4}{center_dot}H{sub 2}O, being temperature independent for Sm{sup 3+} and Eu{sup 3+} but temperature dependent for Tb{sup 3+}, follow the energy gap law with {alpha} {approx} - 10{sup {minus}3} cm and B {approx} 2 x 10{sup 8} s{sup {minus}1}. CP-MAS data show paramagnetic broadening of {sup 13}C resonances which increases with the magnetic moment of Ln{sup 3+}. Surprisingly, no significant shifts in resonance positions corresponding to the changing nature of paramagnetic Ln{sup 3+} ions are observed. 43 refs., 8 figs., 2 tabs.

  2. Chemical and Mineralogical Characterization of Arsenic, Lead, Chromium, and Cadmium in a Metal-contaminated Histosol

    SciTech Connect

    Gao, X.; Schulze, D


    The chemical and mineralogical forms of As, Pb, Cr, and Cd were studied in a metal-contaminated organic soil (Histosol) that received runoff and seepage water from a site that was once occupied by a lead smelter. Soil samples were collected from different depth intervals during both wet and dry seasons and analyzed using bulk powder X-ray diffraction (XRD), synchrotron-based micro X-ray diffraction ({mu}-XRD), and micro X-ray fluorescence ({mu}-SXRF) spectroscopy. There was a clear pattern of mineral distribution with depth that indicated the presence of an intense redox gradient. The oxidized reddish brown surface layer (0-10 cm) was dominated by goethite ({alpha}-FeOOH) and poorly crystalline akaganeite ({beta}-FeOOH). Lead and arsenic were highly associated with these Fe oxides, possibly by forming inner-sphere surface complexes. Gypsum (CaSO{sub 4} {center_dot} 2H{sub 2}O) was abundant in the layer as well, particularly for samples collected during dry periods. Fe(II)-containing minerals, such as magnetite (Fe{sub 3}O{sub 4}) and siderite (FeCO{sub 3}), were identified in the intermediate layers (10-30 cm) where the reductive dissolution of Fe(III) oxides occurred. A number of high-temperature minerals, such as mullite (3Al{sub 2}O{sub 3} {center_dot} 2Si{sub 2}O), corundum ({alpha}-Al{sub 2}O{sub 3}), hematite ({alpha}-Fe{sub 2}O{sub 3}), and wustite (FeO) were identified in the subsurface and they probably formed as a result of a burning event. Several sulfide minerals were identified in the most reduced layers at depths > 30 cm. They included realgar (AsS), alacranite (As{sub 4}S{sub 4}), galena (PbS), and sphalerite (Zn, Fe{sup 2+})S, and a series of Fe sulfides, including greigite (Fe{sup 2+}Fe{sub 2}{sup 3+} S{sub 4}), pyrrhotite (Fe{sub 1-x}S), mackinawite (FeS), marcasite (FeS{sub 2}), and pyrite (FeS{sub 2}). Most of these minerals occurred as almost pure phases in sub-millimeter aggregates and appeared to be secondary phases that had precipitated from

  3. Rare-Earth-Free High-Efficiency Narrow-Band Red-Emitting Mg3Ga2GeO8:Mn4+ Phosphor Excited by Near-UV Light for White-Light-Emitting Diodes.


    Ding, Xin; Zhu, Ge; Geng, Wanying; Wang, Qian; Wang, Yuhua


    A series of novel red emission Mg3Ga2GeO8 (MGG):Mn(4+) phosphors under near-UV (NUV) excitation are synthesized successfully by traditional high-temperature solid-state reaction. The structure of Mg3Ga2GeO8 is investigated by high-resolution transmission electron microscopy, scanning electron microscopy, and powder X-ray diffraction (XRD) Rietveld refinement. It has one octahedral site and one tetrahedral site in the crystal structure. According to XRD and photoluminescence (PL) property analysis, Mn(4+) can occupy an octahedral (Mg(2+)/Ga(3+)) site. The PL properties are investigated by diffuse-reflectance, emission, excitation, and temperature-dependent spectroscopy and decay curves. It can emit red light peaking at 659 nm under NUV excitation. The critical quenching concentration of Mn(4+) was about 0.5 mol %. The concentration quenching mechanism could be a d-d interaction for the Mn(4+) center. The CIE chromaticity coordinates and full-width at half-maximum are (0.295, 0.677) and 24 nm, respectively. It demonstrated that MGG:Mn(4+) has high color purity. The PL intensity of MGG:0.5% Mn(4+) drops to 72% when the temperature is raised up to 150 °C. Furthermore, MGG:0.5% Mn(4+) exhibits outstanding quantum efficiency (64.7%). By tuning of the weight ratio of blue, green, and red phosphors, the fabricated white-light-emitting diodes using a 405 nm GaN NUV chip combined with a blend of blue phosphor BAM:Eu(2+), green phosphor Sr2SiO4:Eu(2+), and red-emitting phosphor MGG:Mn(4+) driven by 40 mA current can get white light with chromaticity coordinates (0.316, 0.375) and CCT = 3340 K. This demonstrates that MGG:Mn(4+) is a potential red phosphor matching NUV LED chips to get white light. PMID:26666169

  4. Nurnet- A case of crowdsourcing for geographic knowledge production.

    NASA Astrophysics Data System (ADS)

    Spanu, Valentina; Demontis, Roberto; Lorrai, Eva; Muscas, Laura


    Nurnet - The net of the Nuraghes ( is a Foundation of Participation aiming to promote the culture of the Pre-Nuragical (3200-2700 BC) and Nuragical period (up to the 2nd century AD) in the island of Sardinia (Italy). It is fed by a net of conventional social connections or through social web- networks empowered by private citizens, agents and public administrations sharing the same goals and interests. CRS4 (Center for Advanced Studies, Research and Development in Sardinia), in collaboration with Nurnet Foundation, developed a geoportal ( on the web, at the moment as a beta version, enable the users to access and share information. The application is based on Geographic Information System (GIS) and Participatory Geographic Information System (PGIS) and it manages several types of information like archaeological sites, artifacts and museum information. Such information comes from the users of the portal and from other sources that make the data available, according to the "open data" philosophy: free data accessible to anyone. The users are encouraged to generate and manage information of archaeological sites in the Italian island of Sardinia about location, history, preservation of the archaeological patrimony, pictures and videos to enrich a wide geo-database pertaining the big heritage of this region in every place there are nuraghes, dolmens domus de janas, menhirs, villages and sacred pits. A specific data model has been created, the geo-attribute is in WGS84 and it can be a point, a line or a polygon. There are three types of actors: viewers, editors and validators. The viewer can query data with a map or a form; the editor can insert and update data through maps using Google or Open Street Map as base layer; the validators are the experts working behind the geoportal: they evaluate and validate the data quality (archaeologists for example). To implement the geoportal, open source software has been used and

  5. A formal classification of 3D medial axis points and their local geometry.


    Giblin, Peter; Kimia, Benjamin B


    This paper proposes a novel hypergraph skeletal representation for 3D shape based on a formal derivation of the generic structure of its medial axis. By classifying each skeletal point by its order of contact, we show that, generically, the medial axis consists of five types of points, which are then organized into sheets, curves, and points: 1) sheets (manifolds with boundary) which are the locus of bitangent spheres with regular tangency A1(2) (Ak(n) notation means n distinct k-fold tangencies of the sphere of contact, as explained in the text); two types of curves, 2) the intersection curve of three sheets and the locus of centers of tritangent spheres, A1(3), and 3) the boundary of sheets, which are the locus of centers of spheres whose radius equals the larger principal curvature, i.e., higher order contact A3 points; and two types of points, 4) centers of quad-tangent spheres, A1(4), and 5) centers of spheres with one regular tangency and one higher order tangency, A1A3. The geometry of the 3D medial axis thus consists of sheets (A1(2)) bounded by one type of curve (A3) on their free end, which corresponds to ridges on the surface, and attached to two other sheets at another type of curve (A1(3)), which support a generalized cylinder description. The A3 curves can only end in A1A3 points where they must meet an A1(3) curve. The A1(3) curves meet together in fours at an A1(4) point. This formal result leads to a compact representation for 3D shape, referred to as the medial axis hypergraph representation consisting of nodes (A1(4) and A1A3 points), links between pairs of nodes (A1(3) and A3 curves) and hyperlinks between groups of links (A1(2) sheets). The description of the local geometry at nodes by itself is sufficient to capture qualitative aspects of shapes, in analogy to 2D. We derive a pointwise reconstruction formula to reconstruct a surface from this medial axis hypergraph together with the radius function. Thus, this information completely

  6. Reaction of H{sub 2} and H{sub 2}S with CoMoO{sub 4} and NiMoO{sub 4}: TPR, XANES, time-resolved XRD, and molecular-orbital studies

    SciTech Connect

    Rodriguez, J.A.; Chaturvedi, S.; Hanson, J.C.; Brito, J.L.


    The combination of two metals in an oxide matrix can produce materials with novel physical and chemical properties. The reactivity of a series of cobalt and nickel molybdates ({alpha}-AMoO{sub 4}, {beta}-AMoO{sub 4}, and AmoO{sub 4}{center_dot}nH{sub 2}O; A = Co or Ni) toward H{sub 2} and H{sub 2}S was examined using temperature programmed reduction (TPR), synchrotron-based X-ray powder diffraction (XRD), and X-ray absorption near-edge-spectroscopy (XANES). In general, the cobalt and nickel molybdates are more reactive toward H{sub 2} and easier to reduce than pure molybdenum oxides: MoO{sub 2} < MoO{sub 3} < CoMoO{sub 4} < NiMoO{sub 4}. The interaction of H{sub 2} with surfaces of {alpha}-NiMoO{sub 4}, {alpha}-CoMoO{sub 4}, and {alpha}-MoO{sub 3} was investigated using ab initio SCF calculations and cluster models. The mixed-metal oxides are easier to reduce due to the combination of two factors. First, it is easier to adsorb and dissociate H{sub 2} on Ni or Co sites than on Mo sites of an oxide. And second, as a result of differences in the strength of the metal-oxygen bonds, it is easier to remove oxygen as water from the nickel and cobalt molybdates than from MoO{sub 3} or MoO{sub 2}. The extra reactivity that the Co and Ni atoms provide also makes the rate of sulfidation of the cobalt and nickel molybdates faster than that of pure molybdenum oxides. For the adsorption of H{sub 2}S, HS, and S on {alpha}-NiMoO{sub 4} and {alpha}-MoO{sub 3} clusters, the results of ab initio SCF calculations show bigger bonding energies on the Ni sites than on the Mo sites. In these systems, the oxidation state of the Ni atoms is substantially lower (i.e., larger electron density) than that of the Mo atoms, favoring the formation of Ni {r_arrow} SH and Ni {r_arrow} S dative bonds. Results of time-resolved XRD and XANES indicate that the reduced AMoO{sub 4} compounds can be regenerated by reaction with O{sub 2} at high temperatures (350--450 C). A similar procedure (S{sub a} + O

  7. Design of a subcritical multiplying low-enriched uranium externally driven neutron assembly at the Los Alamos neutron science center

    SciTech Connect

    Gavron, Victor


    The Sandia Pulsed Reactor (SPR) has had a long history of supplying short intense neutron bursts to test the survivability of critical weapons components. The most recent version, SPR III, was resurrected in 2005 in support of critical survivability testing for W-76 Life Extension Program and other testing for the Qualification Alternatives to SPR program. SPR has now been decommissioned. The SPR had a cylindrical shape, with an internal cylindrical cavity where samples were placed for testing. The approximate dimensions of the cavity were 16.5 cm radius, and 38.1 cm high. The uniformity of the fluence over the entire volume was {+-} 25%. The nominal fluence was 5.4 {center_dot} 10{sup 14} n/cm{sup 2}, 1 MeV Si equivalent (Si equivalent implies that the neutron spectrum, at energies other than 1 MeV, is weighted by its relative damage potential in silicon), with a pulse duration of 55 microseconds, FWHM. We propose a new facility as a replacement to the SPR pulsed neutron capabilities, utilizing the proton linear accelerator at the Los Alamos Neutron Science Center (LANSCE). Currently, LANSCE provides neutron beams generated by the 800 MeV proton beam, over 13 decades of energy, to five different facilities. LANSCE is in the process of being refurbished; the refurbishment project (LANSCE-R) is funded and due to be completed by 2014. In parallel to the refurbishment, the experimental user program will continue and provide 3000 hours of beam per year. LANSCE is also considering upgrade options in the framework of MaRIE (Materials and Radiation Interactions in Extreme). MaRIE is planned to be the new signature facility for Los Alamos for the foreseeable future. Hence, they expect LANSCE to continue to operate and provide beams for decades t come. They propose to use the 800 MeV proton beam, extracted from the Proton Storage Ring (PSR), to initiate a neutron pulse in a sub-critical multiplying assembly, fabricated from Low-Enriched Uranium (LEU). The reason for using

  8. Hydrothermal Synthesis and Structural Characterization of Novel Zn-Triazole-Benzenedicarboxylate Frameworks

    SciTech Connect

    Park, Hyunsoo; Moureau, David M.; Parise, John B.


    Three new metal-organic coordination polymers were synthesized hydrothermally using Zn2+ ion, 1,2,4-triazole, and 1,4-benzenedicarboxylic acid (BDC): Zn5(H2O)2(C2H2N3)4(C8H4O4)3 {center_dot} 3.9H2O (1), Zn2(C2H2N3)2(C2H3N3)(C8H4O4) {center_dot} 2.5H2O (2), and Zn4(H2O)2(C2H2N3)4(C8H4O4)2 {center_dot} 14H2O (3). Their crystal structures were determined by single-crystal X-ray diffraction. Their thermal properties were examined by thermogravimetric analysis. Structure 1 crystallizes in the monoclinic P21/n space group with a = 10.192(2) {angstrom}, b = 17.764(4) {angstrom}, c = 24.437(5) {angstrom}, {beta} = 91.19(3){sup o}, and V = 4423.3(15) {angstrom}3. Structure 2 crystallizes in the triclinic P space group with a = 7.797(2) {angstrom}, b = 10.047(2) {angstrom}, c = 13.577(3) {angstrom}, {alpha} = 110.18(3){sup o}, {beta} = 105.46(3){sup o}, {gamma} = 93.90(3){sup o}, and V = 947.0(3) {angstrom}3. Structure 3 crystallizes in monoclinic P21/n space group with a = 13.475(3) {angstrom}, b = 26.949(5) {angstrom}, c = 13.509(3) {angstrom}, {beta} = 95.18(3){sup o}, and V = 4885.7(17) {angstrom}3. In structure 1, the units of the triazole-Zn polyhedra are linked by BDC in a zigzag fashion to create the stacking of phenyl groups along the a axis. In structure 2, both triazole and BDC bridge Zn polyhedra in the (011) plane, resulting in the eight-membered channels along the a axis. In the case of structure 3, the BDC links the Zn polyhedra along the b axis to form a pillared open framework. This structure is the most porous of the compounds presented in this work.

  9. FY04 Engineering Technology Reports Technology Base

    SciTech Connect

    Sharpe, R M


    exploration of selected technology areas with high strategic potential, such as assessment of university, laboratory, and industrial partnerships. Engineering's five Centers, in partnership with the Division Leaders and Department Heads, focus and guide longer-term investments within Engineering. The Centers attract and retain top staff, develop and maintain critical core technologies, and enable programs. Through their technology-base projects, they oversee the application of known engineering approaches and techniques to scientific and technical problems. The Centers and their Directors are as follows: (1) Center for Computational Engineering: Robert M. Sharpe; (2) Center for Microtechnology and Nanotechnology: Raymond P. Mariella, Jr. (3) Center for Nondestructive Characterization: Harry E. Martz, Jr.; (4) Center for Precision Engineering: Keith Carlisle; and (5) Center for Complex Distributed Systems: Gregory J. Suski, Acting Director.

  10. Oligomeric rare-earth-metal halide clusters. Three structures built of (Y{sub 16}Z{sub 4})Br{sub 36} units (Z = Ru, Ir)

    SciTech Connect

    Steinward, S.J.; Corbett, J.D.


    Suitable reactions in sealed Nb tubing at 850-950 {degrees}C gave good yields of a family of oligomeric cluster phases that were characterized by single-crystal X-ray diffraction means. The basic Y{sub 16}Z{sub 4} units ({approximately}{bar 4} symmetry) can be derived from 2+2 condensation of centered Y{sub 6}Br{sub 12}Z-type clusters or as tetracapped truncated tetrahedra Y{sub 16} that are centered by a large tetrahedral Z{sub 4}. These are surrounded by 36 bromine atoms which bridge edges or cap faces of the Y{sub 16}Z{sub 4} nuclei and, in part, bridge to metal atoms in other clusters. The principal bonding appears to be Y-Z and Y-Br, with weaker Y-Y ({bar d} {approximately} 3.70 {angstrom}) and negligible Z-Z interactions. The phase Y{sub 16}Br{sub 20}Ru{sub 4} (P4{sub 2}/nnm, Z = 2; a = 11.662(1) {angstrom}, c = 16.992 (2) {angstrom}) is isostructural with Y{sub 16}I{sub 20}Ru{sub 4} and with the new Sc{sub 16-} Br{sub 20}Z{sub 4} (Z = Fe, Os). Syntheses only in the presence of Ir and ABr-YBr{sub 3} fluxes (A = K-Cs) produce Y{sub 16-} Br{sub 24}Ir{sub 4} (Fddd, Z = 8; a = 11.718(3) {angstrom}, b = 22.361(7) {angstrom}, c = 44.702(2) {angstrom}), in which the electron-richer Ir interstitials are compensated by four additional bromine atoms and altered bridging between macroclusters. Larger amounts of YBr{sub 3} yield a third example, Y{sub 20}Br{sub 36}Ir{sub 4} (Y{sub 16}Br{sub 24}Ir{sub 4}{center_dot}4YBr{sub 3}, I4{sub 1}a, Z = 4; a = 12.699(1) {angstrom}, c = 45.11- (1){angstrom}). Here infinite zigzag chains of YBr{sub 6/2} octahedra that share cis edges lie between and bridge to the Y{sub 16}Ir{sub 4} clusters. All of these phases contain 60-electron, closed-shell macroclusters. Y{sub 16}Br{sub 20}Ru{sub 4} and Y{sub 20}Br{sub 36}ir{sub 4} were found to exhibit temperature-independent (Van Vleck) paramagnetism with values typical of those found for other rare-earth-metal, zirconium, niobium, and tantalum cluster halides.

  11. Homolytic dissociation of the vulcanization accelerator tetramethylthiuram disulfide (TMTD) and structures and stabilities of the related radicals Me2NCSn* (n = 1-4).


    Steudel, Ralf; Steudel, Yana; Mak, Adrian Matthew; Wong, Ming Wah


    The homolytic dissociation of the important vulcanization accelerator tetramethylthiuram disulfide (TMTD) has been studied by ab initio calculations according to the G3X(MP2) and G3X(MP2)-RAD theories. Homolytic cleavage of the SS bond requires a low enthalpy of 150.0 kJ mol-1, whereas 268.0 kJ mol-1 is needed for the dissociation of one of the C-S single bonds. To cleave one of the SS bonds of the corresponding trisulfide (TMTT) requires 191.1 kJ mol-1. Me2NCS2* is a particularly stable sulfur radical as reflected in the low S-H bond dissociation enthalpy of the corresponding acid Me2NC(=S)SH (301.7 kJ mol-1). Me2NCS2* (2B2) is a sigma radical characterized by the unpaired spin density shared equally between the two sulfur atoms and by a 4-center (NCS2) delocalized pi system. The ESR g-tensors of the radicals Me2NCSn* (n = 1-3) have been calculated. Both TMTD and the mentioned radicals form stable chelate complexes with a Li+ cation, which here serves as a model for the zinc ions used in accelerated rubber vulcanization. Although the binding energy of the complex [Li(TMTD)]+ is larger than that of the isomeric species [Li(S2CNMe2)2]+ (12), the dissociation enthalpy of TMTD as a ligand is smaller (125.5 kJ mol-1) than that of free TMTD. In other words, the homolytic dissociation of the SS bonds of TMTD is facilitated by the presence of Li+ ions. The sulfurization of TMTD in the presence of Li+ to give the paramagnetic complex [Li(S3CNMe2)2]+ is strongly exothermic. These results suggest that TMTD reacts with naked zinc ions as well as with the surface atoms of solid zinc oxide particles in an analogous manner producing highly reactive complexes, which probably initiate the crosslinking process during vulcanization reactions of natural or synthetic rubber accelerated by TMTD/ZnO. PMID:17137356

  12. Source Signatures of Fine Particulate Matter from Petroleum Refining and Fuel Use

    SciTech Connect

    Gerald P. Huffman; Frank E. Huggins; Naresh Shah; Robert Huggins


    Combustion experiments were carried out on four different residual fuel oils in a 732 kW boiler. Particulate matter (PM) emission samples were separated aerodynamically by a cyclone into fractions that were nominally less than and greater than 2.5 microns in diameter. However, examination of several of the samples by computer-controlled scanning electron microscopy (CCSEM) revealed that part of the <2.5 micron fraction (PM{sub 2.5}) in fact consists of carbonaceous cenospheres and vesicular particles that range up to 10 microns in diameter. X-ray absorption fine structure (XAFS) spectroscopy data were obtained at the S, V, Ni, Fe, Cu, Zn, and As Kedges, and at the Pb L-edge. Deconvolution of the x-ray absorption near edge structure (XANES) region of the S spectra established that the dominant molecular forms of S present were sulfate (26-84% of total S) and thiophene (13-39% of total S). Sulfate was greater in the PM{sub 2.5} samples than in the >2.5 micron samples (PM{sub 2.5+}). Inorganic sulfides and elemental sulfur were present in lower percentages. The Ni XANES spectra from all of the samples agree fairly well with that of NiSO4, while most of the V spectra closely resemble that of vanadyl sulfate (VO{center_dot}SO{sub 4}{center_dot}xH{sub 2}O). The other metals investigated (Fe, Cu, Zn, and Pb) were also present predominantly as sulfates. Arsenic is present as an arsenate (As{sup +5}). X-ray diffraction patterns of the PM{sub 2.5} fraction exhibit sharp lines due to sulfate compounds (Zn, V, Ni, Ca, etc.) superimposed on broad peaks due to amorphous carbons. All of the samples contain a significant organic component, with the LOI ranging from 64 to 87 % for the PM{sub 2.5} fraction and from 88 to 97% for the PM{sub 2.5+} fraction. {sup 13}C nuclear magnetic resonance (NMR) analysis indicates that the carbon is predominantly condensed in graphitic structures. Aliphatic structure was detected in only one of seven samples examined.

  13. Novel Potent Hepatitis C Virus NS3 Serine Protease Inhibitors Derived from Proline-Based Macrocycles

    SciTech Connect

    Chen, Kevin X.; Njoroge, F. George; Arasappan, Ashok; Venkatraman, Srikanth; Vibulbhan, Bancha; Yang, Weiying; Parekh, Tejal N.; Pichardo, John; Prongay, Andrew; Cheng, Kuo-Chi; Butkiewicz, Nancy; Yao, Nanhua; Madison, Vincent; Girijavallabhan, Viyyoor


    The hepatitis C virus (HCV) NS3 protease is essential for viral replication. It has been a target of choice for intensive drug discovery research. On the basis of an active pentapeptide inhibitor, 1, we envisioned that macrocyclization from the P2 proline to P3 capping could enhance binding to the backbone Ala156 residue and the S4 pocket. Thus, a number of P2 proline-based macrocyclic {alpha}-ketoamide inhibitors were prepared and investigated in an HCV NS3 serine protease continuous assay (K*{sub i}). The biological activity varied substantially depending on factors such as the ring size, number of amino acid residues, number of methyl substituents, type of heteroatom in the linker, P3 residue, and configuration at the proline C-4 center. The pentapeptide inhibitors were very potent, with the C-terminal acids and amides being the most active ones (24, K*{sub i} = 8 nM). The tetrapeptides and tripeptides were less potent. Sixteen- and seventeen-membered macrocyclic compounds were equally potent, while fifteen-membered analogues were slightly less active. gem-Dimethyl substituents at the linker improved the potency of all inhibitors (the best compound was 45, K*{sub i} = 6 nM). The combination of tert-leucine at P3 and dimethyl substituents at the linker in compound 47 realized a selectivity of 307 against human neutrophil elastase. Compound 45 had an IC{sub 50} of 130 nM in a cellular replicon assay, while IC{sub 50} for 24 was 400 nM. Several compounds had excellent subcutaneous AUC and bioavailability in rats. Although tripeptide compound 40 was 97% orally bioavailable, larger pentapeptides generally had low oral bioavailability. The X-ray crystal structure of compounds 24 and 45 bound to the protease demonstrated the close interaction of the macrocycle with the Ala156 methyl group and S4 pocket. The strategy of macrocyclization has been proved to be successful in improving potency (>20-fold greater than that of 1) and in structural depeptization.

  14. Radium-thorium disequilibrium and zeolite-water ion exchange in a Yellowstone hydrothermal environment

    SciTech Connect

    Sturchio, N.C.; Bohlke, J.K. ); Binz, C.M. )


    Whole rock samples of hydrothermally altered Biscuit Basin rhyolite from Yellowstone drill cores Y-7 and Y-8 were analyzed for {sup 226}Ra and {sup 230}Th to determine the extent of radioactive disequilibrium and its relation to the rates and mechanisms of element transport in the shallow portion of an active hydrothermal system. The ({sup 226}Ra/{sup 230}Th) activity ratios range from 0.73 to 1.46 and are generally correlated with Th-normalized Ba concentrations (Ba{sub N}). Compositions of clinoptilolite and mordenite in these samples are consistent with ion exchange equilibrium between zeolites and coexisting thermal waters. Average K{sup Ba}{sub d mineral-water} values are 1.0 {center dot} 10{sup 5} mL/g for clinoptilolite and 1.4 {center dot} 10{sup 4} mL/g for mordenite. Apparent diffusivities through matrix porosity estimated for R and Ba range from {approximately}10{sup {minus}12} to {approximately}10{sup {minus}10} cm{sup 2} s{sup {minus}1} in thoroughly zeolitic rhyolite; these rates of diffusion are too low to account for the observed distance scale of ({sup 226}Ra/{sup 230}Th) disequilibrium. The correlated values of ({sup 226}Ra/{sup 230}Th) disequilibrium and Ba{sub N} represent zeolite-water ion exchange equilibrium that is caused by porous flow of water through the rock matrix and by the relatively rapid diffusion of cations within the zeolite lattices. A water flux of at least {approximately}2.5 (cm{sup 3}{sub water}/cm{sup 3}{sub rock}) yr{sup {minus}1} is required to produce measurable ({sup 226}Ra/{sup 230}Th) disequilibrium, whereas at least {approximately}23 (cm{sup 3}{sub water}/cm{sup 3}{sub rock}) yr{sup {minus}1} is required for the sample exhibiting the most extreme ({sup 226}Ra/{sup 230}Th) disequilibrium; these fluxes are much higher than those that can be inferred from net mass transfers of stable species.

  15. New ternary rare-earth metal boride carbides R{sub 15}B{sub 4}C{sub 14} (R=Y, Gd-Lu) containing BC{sub 2} units: Crystal and electronic structures, magnetic properties

    SciTech Connect

    Babizhetskyy, Volodymyr; Simon, Arndt; Mattausch, Hansjuergen; Hiebl, Kurt; Zheng Chong


    The ternary rare-earth boride carbides R{sub 15}B{sub 4}C{sub 14} (R=Y, Gd-Lu) were prepared from the elements by arc-melting followed by annealing in silica tubes at 1270 K for 1 month. The crystal structures of Tb{sub 15}B{sub 4}C{sub 14} and Er{sub 15}B{sub 4}C{sub 14} were determined from single crystal X-ray diffraction data. They crystallize in a new structure type in space group P4/mnc (Tb{sub 15}B{sub 4}C{sub 14}: a=8.1251(5) A, c=15.861(1) A, Z=2, R{sub 1}=0.041 (wR{sub 2}=0.088) for 1023 reflections with I{sub o}>2{sigma}(I{sub o}); Er{sub 15}B{sub 4}C{sub 14}: a=7.932(1) A, c=15.685(2) A, Z=2, R{sub 1}=0.037 (wR{sub 2}=0.094) for 1022 reflections with I{sub o}>2{sigma}(I{sub o})). The crystal structure contains discrete carbon atoms and bent CBC units in octahedra and distorted bicapped square antiprisms, respectively. In both structures the same type of disorder exists. One R atom position needs to be refined as split atom position with a ratio 9:1 indicative of a 10% substitution of the neighboring C{sup 4-} by C{sub 2}{sup 4-}. The actual composition has then to be described as R{sub 15}B{sub 4}C{sub 14.2}. The isoelectronic substitution does not change the electron partition of R{sub 15}B{sub 4}C{sub 14} which can be written as (R{sup 3+}){sub 15}(C{sup 4-}){sub 6}(CBC{sup 5-}){sub 4{center_dot}}e{sup -}. The electronic structure was studied with the extended Hueckel method. The investigated compounds Tb{sub 15}B{sub 4}C{sub 14}, Dy{sub 15}B{sub 4}C{sub 14} and Er{sub 15}B{sub 4}C{sub 14} are hard ferromagnets with Curie temperatures T{sub C}=145, 120 and 50 K, respectively. The coercive field B{sub C}=3.15 T for Dy{sub 15}B{sub 4}C{sub 14} is quite remarkable. - Graphical abstract: The ternary rare earth boride carbides R{sub 15}B{sub 4}C{sub 14} (R=Y, Gd-Lu) were prepared from the elements by arc-melting followed by annealing in silica tubes at 1270 K for 1 month. Tb{sub 15}B{sub 4}C{sub 14} is a new member of the rare-earth metal boride carbide

  16. Step-by-step thermal transformations of a new porous coordination polymer [(H{sub 2}O){sub 5}CuBa(Me{sub 2}mal){sub 2}]{sub n} (Me{sub 2}mal{sup 2-}=dimethylmalonate): Thermal degradation to barium cuprate

    SciTech Connect

    Zauzolkova, Natalya; Dobrokhotova, Zhanna; Lermontov, Anatoly; Zorina, Ekaterina; Emelina, Anna; Bukov, Mikhail; Sidorov, Aleksey; Kiskin, Mikhail; Bogomyakov, Artem; Lytvynenko, Anton; Kolotilov, Sergey; Velikodnyi, Yuriy; Kovba, Maksim


    The reactions of CuSO{sub 4}{center_dot}5H{sub 2}O, dimethylmalonic acid and Ba(OH){sub 2}{center_dot}H{sub 2}O (Cu: H{sub 2}Me{sub 2}mal: Ba=1: 2: 2) in aqueous and aqueous-ethanol solutions (H{sub 2}O: EtOH=1: 1) resulted in formation of 3D-porous coordination polymers [(H{sub 2}O){sub 3}({mu}-H{sub 2}O){sub 2}CuBa({mu}{sub 3}-Me{sub 2}mal)(Me{sub 2}mal)]{sub n} (1) and [({mu}-H{sub 2}O)CuBa({mu}{sub 3}-Me{sub 2}mal)({mu}{sub 4}-Me{sub 2}mal)]{sub n} (2), respectively. It has been shown that compound 2 was an intermediate in the thermal degradation of compound 1. Thorough studies of solid-state thermolysis of 1 and 2 allowed to detect formation of coordination polymer [CuBa({mu}{sub 4}-Me{sub 2}mal)({mu}{sub 5}-Me{sub 2}mal)]{sub n} (3), structure of which was determined by X-ray powder diffraction. It has been found that the channels in polymer 3 were accessible for guest molecules (MeOH). Theoretical estimation of methanol diffusion barrier was carried out. Complete solid-phase thermolysis of 1 and 2 leads to a mixture of BaCuO{sub 2}, BaCO{sub 3}, and CuO. Special conditions for obtaining of a crystalline phase of pure cubic BaCuO{sub 2} were determined. - Graphical abstract: Step-by-step transformation of new coordination polymer [(H{sub 2}O){sub 5}CuBa(Me{sub 2}mal){sub 2}]{sub n} to [(H{sub 2}O)CuBa(Me{sub 2}mal){sub 2}]{sub n} and [CuBa(Me{sub 2}mal){sub 2}]{sub n} were performed. Dehydration of initial compound leads to structural changes of 12-membered ring fragment. All compounds have porous structure. The final product of thermal decomposition is crystalline phase of individual cubic BaCuO{sub 2}. Highlights: Black-Right-Pointing-Pointer New 3D-polymers [(H{sub 2}O){sub 5}CuBa(Me{sub 2}mal){sub 2}]{sub n} and [(H{sub 2}O)CuBa(Me{sub 2}mal){sub 2}]{sub n} were synthesized. Black-Right-Pointing-Pointer Thermal analysis showed step-by-step transformations of [(H{sub 2}O){sub 5}CuBa(Me{sub 2}mal){sub 2}]{sub n}. Black-Right-Pointing-Pointer Crystalline

  17. Separation of flue-gas scrubber sludge into marketable products

    SciTech Connect

    Kawatra, S.K.; Eisele, T.C.


    A tremendous amount of wet flue-gas desulfurization scrubber sludge (estimated 20 million metric tons per year in the US) is currently being landfilled at a huge cost to utility companies. Scrubber sludge is the solid precipitate produced during desulfurization of flue-gas from burning high sulfur coal. The amount of this sludge is expected to increase in the near future due to ever increasing governmental regulation concerning the amount of sulfur emissions. Scrubber sludge is a fine, grey colored powder that contains calcium sulfite hemihydrate (CaSO{sub 3} {center_dot} 1/2H{sub 2}), calcium sulfate dihydrate (CaSO{sub 4} {center_dot} 2H{sub 2}O), limestone (CaCO{sub 3}), silicates, and iron oxides. This material can continue to be landfilled at a steadily increasing cost, or an alternative for utilizing this material can be developed. This study explores the characteristics of a naturally oxidized wet flue-gas desulfurization scrubber sludge and uses these characteristics to develop alternatives for recycling this material. In order for scrubber sludge to be used as a feed material for various markets, it was necessary to process it to meet the specifications of these markets. A physical separation process was therefore needed to separate the components of this sludge into useful products at a low cost. There are several physical separation techniques available to separate fine particulates. These techniques can be divided into four major groups: magnetic separation, electrostatic separation, physico-chemical separation, and density-based separation. The properties of this material indicated that two methods of separation were feasible: water-only cycloning (density-based separation), and froth flotation (physico-chemical separation). These processes could be used either separately, or in combination. The goal of this study was to reduce the limestone impurity in this scrubber sludge from 5.6% by weight to below 2.0% by weight. The resulting clean calcium

  18. Five new Zn(II) and Cd(II) coordination polymers constructed by 3,5-bis-oxyacetate-benzoic acid: Syntheses, crystal structures, network topologies and luminescent properties

    SciTech Connect

    Jiang Xianrong; Yuan Hongyan; Feng Yunlong


    Five Zn(II) and Cd(II) coordination polymers, [Zn{sub 2}(BOABA)(bpp)(OH)]{center_dot}0.5H{sub 2}O (1), [Cd{sub 3}(BOABA){sub 2}(bpp){sub 2}(H{sub 2}O){sub 6}]{center_dot}2H{sub 2}O (2), [Cd{sub 3}(BOABA){sub 2}(2,2 Prime -bipy){sub 3}(H{sub 2}O){sub 4}]{center_dot}5.5H{sub 2}O (3), [CdNa(BOABA)(H{sub 2}O)]{sub 2}{center_dot}H{sub 2}O (4) and [Cd{sub 2}(BOABA)(bimb)Cl(H{sub 2}O){sub 2}]{center_dot}H{sub 2}O (5) (H{sub 3}BOABA=3,5-bis-oxyacetate-benzoic acid, bpp=1,3-bi(4-pyridyl)propane, 2,2 Prime -bipy=2,2 Prime -bipyridine, bimb=1,4-bis(imidazol-1 Prime -yl)butane), have been solvothermally synthesized and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra and TG analyses. 1 is an uninodal 4-connected 2D square grid network based on binuclear zinc clusters. 2 is 2D wavelike layer structure and further linked by hydrogen bonds into the final 3D (5,6,6)-connected topology network. 3 is 3-connected 2D topology network and the 2,2 Prime -bipy ligands decorate in two different types. 4 is a (4,8)-connected 2D topology network with heterocaryotic {l_brace}Cd{sub 2}Na{sub 2}{r_brace} clusters and BOABA{sup 3-} ligands. 5 can be rationalized as a (3,10)-connected 3D topology network with tetranuclear {l_brace}Cd{sub 4}Cl{sub 2}{r_brace} clusters and BOABA{sup 3-} ligands. Meanwhile, photoluminescence studies revealed that these five coordination polymers display strong fluorescent emission bands in the solid state at room temperature. - Graphical abstract: Five new d{sup 10} metal(II) coordination polymers based on H{sub 3}BOABA ligand were obtained and characterized. They display different topological structures and luminescent properties. Highlights: Black-Right-Pointing-Pointer Five d{sup 10} metal(II) polymers based on 3,5-bis-oxyacetate-benzoic acid were obtained. Black-Right-Pointing-Pointer The polymers were structurally characterized by single-crystal X-ray diffraction. Black-Right-Pointing-Pointer Polymers 1-5 display different


    SciTech Connect

    Robert C. Brown; Maohong Fan; Adrienne Cooper


    Absorption of sulfur dioxide from a simulated flue gas was investigated for the production of polymeric ferric sulfate (PFS), a highly effective coagulant useful in treatment of drinking water and wastewater. The reaction for PFS synthesis took place near atmospheric pressure and at temperatures of 30-80 C. SO{sub 2} removal efficiencies greater than 90% were achieved, with ferrous iron concentrations in the product less than 0.1%. A factorial analysis of the effect of temperature, oxidant dosage, SO{sub 2} concentration, and gas flow rate on SO{sub 2} removal efficiency was carried out, and statistical analyses are conducted. The solid PFS was also characterized with different methods. Characterization results have shown that PFS possesses both crystalline and non-crystalline structure. The kinetics of reactions among FeSO{sub 4} {center_dot} 7H{sub 2}O, NaHSO{sub 3} and NaClO{sub 3} was investigated. Characterizations of dry PFS synthesized from SO{sub 2} show the PFS possesses amorphous structure, which is desired for it to be a good coagulant in water and wastewater treatment. A series of lab-scale experiments were conducted to evaluate the performance of PFS synthesized from waste sulfur dioxide, ferrous sulfate and sodium chlorate. The performance assessments were based on the comparison of PFS and other conventional and new coagulants for the removal of turbidity and arsenic under different laboratory coagulant conditions. Pilot plant studies were conducted at Des Moines Water Works in Iowa and at the City of Savannah Industrial and Domestic (I&D) Water Treatment Plant in Port Wentworth, Georgia. PFS performances were compared with those of conventional coagulants. The tests in both water treatment plants have shown that PFS is, in general, comparable or better than other coagulants in removal of turbidity and organic substances. The corrosion behavior of polymeric ferric sulfate (PFS) prepared from SO{sub 2} and ferric chloride (FC) were compared. Results

  20. Holocene evolution of a wave-dominated fan-delta: Godavari delta, India

    NASA Astrophysics Data System (ADS)

    Saito, Y.; Nageswara Rao, K.; Nagakumar, K.; Demudu, G.; Rajawat, A.; Kubo, S.; Li, Z.


    The Godavari delta is one of the world's largest wave-dominated deltas. The Godavari River arises in the Western Ghats near the west coast of India and drains an area of about 3.1x10^5 km^2, flowing about 1465 km southeast across the Indian peninsula to the Bay of Bengal. The Godavari delta consists of a gentle seaward slope from its apex (12 m elevation) at Rajahmundry and a coastal beach-ridge plain over a distance of about 75 km and covers ~5200 km^2 as a delta plain. The river splits into two major distributary channels, the Gautami and the Vasishta, at a barrage constructed in the mid-1800s. The coastal environment of the deltaic coast is microtidal (~1 m mean tidal range) and wave-dominated (~1.5 m mean wave height in the June-September SW monsoon season, ~0.8 m in the NE monsoon season). Models of the Holocene evolution of the Godavari delta have changed from a zonal progradation model (e.g. Nageswara Rao & Sadakata, 1993) to a truncated cuspate delta model (Nageswara Rao et al., 2005, 2012). Twelve borehole cores (340 m total length), taken in the coastal delta plain during 2010-2013, yielded more than 100 C-14 dates. Sediment facies and C-14 dates from these and previous cores and remote-sensing data support a new delta evolution model. The Holocene coastal delta plain is divided into two parts by a set of linear beach ridges 12-14 km landward from the present shoreline in the central part of the delta. The location of the main depocenter (lobe) has shifted during the Holocene from 1) the center to 2) the west, 3) east, 4) center, 5) west, and 6) east. The linear beach ridges separate the first three from the last three stages. These lobe shifts are controlled by river channel shifts near the apex. Just as the current linear shoreline of the central part of the delta and the concave-up nearshore topography are the result of coastal erosion of a cuspate delta, the linear beach ridges indicate a former eroded shoreline. An unconformity within the deltaic

  1. Redgillite, Cu[subscript 6](OH)1 0(SO[subscript 4]).2H[subscript 2]O, a new mineral from Caldbeck Fells, Cumbria, England, UK: Description and crystal structure

    SciTech Connect

    Pluth, J.J.; Steele, I.M.; Kampf, A.R.; Green, D.I.


    Redgillite, Cu{sub 6}(OH){sub 10}(SO{sub 4}) {center_dot} H{sub 2}O, space group P2{sub 1}/c, a 3.155(3) {angstrom}, b 10.441(8) {angstrom}, c 19.436(16) {angstrom}, {beta} 90.089(13){sup o}, V = 640.2(9) {angstrom}{sup 3}, Z = 2, is a new mineral from Silver Gill, Caldbeck Fells, Cumbria, England. The strongest six lines of the X-ray powder-diffraction pattern [d in {angstrom}, (I) (hkl)] are: 9.72 (90) (002), 7.11 (100) (012), 4.60 (30) (022), 4.068 (20) (023), 2.880 (30) (112,11{bar 2}), 2.318 (50) (131,13{bar 1}). It occurs as translucent to transparent grass-green bladed crystals up to 0.15 mm long with squared-off or tapering terminations; usually in radiating groups. Forms observed are {l_brace}001{r_brace} prominent, {l_brace}010{r_brace} as composite stepped faces, and {l_brace}100{r_brace} irregular. Redgillite has white streak, vitreous lustre and Mohs hardness of {approx}2. Blades are slightly flexible with irregular fracture and exhibit a perfect {l_brace}001{r_brace} cleavage and good {l_brace}100{r_brace} and {l_brace}010{r_brace} cleavages. The measured density (by sink-float) is 3.45(5) g/cm{sup 3}; the calculated density is 3.450 g/cm{sup 3}. The mineral dissolves slowly in dilute HCl. Redgillite is biaxial-negative with {alpha} = 1.693(2), {beta} = 1.721(2), {gamma} = 1.723(2), 2V = 30(2){sup o} (meas.) and 30{sup o} (calc.); dispersion is r > v, medium; pleochroism: Y blue-green > X blue-green > Z yellow-green; orientation: X c, Y = b, Z a. Electron microprobe analyses yielded CuO 68.9, SO{sub 3} 11.6, total 80.5. With water inferred from the structure analysis, the empirical formula is: Cu{sub 5.995}(OH){sub 9.991}(SO{sub 4}){sub 1.003} {center_dot} H{sub 2}O. Redgillite is typically found in thin fractures in partly oxidized sulphides where it is commonly associated with langite and more rarely with malachite, cuprite, connellite and brochantite. The name is for the Red Gill mine, from which the mineral is best known. The crystal structure of

  2. Yegorovite, Na4[Si4O8(OH)4]·7H2O, a new mineral from the Lovozero alkaline pluton, Kola Peninsula

    NASA Astrophysics Data System (ADS)

    Pekov, I. V.; Zubkova, N. V.; Chukanov, N. V.; Zadov, A. E.; Grishin, V. G.; Pushcharovsky, D. Yu.


    of two types: [NaO(OH)2(H2O)3] and [NaO(OH)(H2O)4] centered by Na. The mineral was named in memory of Yu. K. Yegorov-Tismenko (1938-2007), outstanding Russian crystallographer and crystallochemist. The type material of yegorovite has been deposited at the Fersman Mineralogical Museum of Russian Academy of Sciences, Moscow.

  3. Analysis of Parallel Burn Without Crossfeed TSTO RLV Architectures and Comparison to Parallel Burn With Crossfeed and Series Burn Architectures

    NASA Technical Reports Server (NTRS)

    Smith, Garrett; Phillips, Alan


    There are currently three dominant TSTO class architectures. These are Series Burn (SB), Parallel Burn with crossfeed (PBw/cf), and Parallel Burn without crossfeed (PBncf). The goal of this study was to determine what factors uniquely affect PBncf architectures, how each of these factors interact, and to determine from a performance perspective whether a PBncf vehicle could be competitive with a PBw/cf or SB vehicle using equivalent technology and assumptions. In all cases, performance was evaluated on a relative basis for a fixed payload and mission by comparing gross and dry vehicle masses of a closed vehicle. Propellant combinations studied were LOX: LH2 propelled orbiter and booster (HH) and LOX: Kerosene booster with LOX: LH2 orbiter (KH). The study conclusions were: 1) a PBncf orbiter should be throttled as deeply as possible after launch until the staging point. 2) a detailed structural model is essential to accurate architecture analysis and evaluation. 3) a PBncf TSTO architecture is feasible for systems that stage at mach 7. 3a) HH architectures can achieve a mass growth relative to PBw/cf of < 20%. 3b) KH architectures can achieve a mass growth relative to Series Burn of < 20%. 4) center of gravity (CG) control will be a major issue for a PBncf vehicle, due to the low orbiter specific thrust to weight ratio and to the position of the orbiter required to align the nozzle heights at liftoff. 5 ) thrust to weight ratios of 1.3 at liftoff and between 1.0 and 0.9 when staging at mach 7 appear to be close to ideal for PBncf vehicles. 6) performance for all vehicles studied is better when staged at mach 7 instead of mach 5. The study showed that a Series Burn architecture has the lowest gross mass for HH cases, and has the lowest dry mass for KH cases. The potential disadvantages of SB are the required use of an air-start for the orbiter engines and potential CG control issues. A Parallel Burn with crossfeed architecture solves both these problems, but the


    SciTech Connect

    Bannochie, C.; Pareizs, J.; Click, D.; Zamecnik, J.


    A sample of PUREX sludge from Tank 4 was characterized, and subsequently combined with a Tank 51 sample (Tank 51-E1) received following Al dissolution, but prior to a supernate decant by the Tank Farm, to perform a settling and washing study to support Sludge Batch 6 preparation. The sludge source for the majority of the Tank 51-E1 sample is Tank 12 HM sludge. The Tank 51-E1 sample was decanted by SRNL prior to use in the settling and washing study. The Tank 4 sample was analyzed for chemical composition including noble metals. The characterization of the Tank 51-E1 sample, used here in combination with the Tank 4 sample, was reported previously. SRNL analyses on Tank 4 were requested by Liquid Waste Engineering (LWE) via Technical Task Request (TTR) HLE-TTR-2009-103. The sample preparation work is governed by Task Technical and Quality Assurance Plan (TTQAP), and analyses were controlled by an Analytical Study Plan and modifications received via customer communications. Additional scope included a request for a settling study of decanted Tank 51-E1 and a blend of decanted Tank 51-E1 and Tank 4, as well as a washing study to look into the fate of undissolved sulfur observed during the Tank 4 characterization. The chemistry of the Tank 4 sample was modeled with OLI Systems, Inc. StreamAnalyzer to determine the likelihood that sulfate could exist in this sample as insoluble Burkeite (2Na{sub 2}SO{sub 4} {center_dot} Na{sub 2}CO{sub 3}). The OLI model was also used to predict the composition of the blended tank materials for the washing study. The following conclusions were drawn from the Tank 4 analytical results reported here: (1) Any projected blend of Tank 4 and the current Tank 51 contents will produce a SB6 composition that is lower in Ca and U than the current SB5 composition being processed by DWPF. (2) Unwashed Tank 4 has a relatively large initial S concentration of 3.68 wt% on a total solids basis, and approximately 10% of the total S is present as an

  5. Response of atmosphere circulation on global and regional scales to the two El Niño flavors

    NASA Astrophysics Data System (ADS)

    Zheleznova, Irina; Gushchina, Daria


    Indonesia, south to the equator prevails air descent. During El Niño Modoki anomalous air rising occurs over the central equatorial Pacific, while descending motion develop to the east (mainly in the equatorial regions of the Southern Hemisphere) and to the west (in the Northern Hemisphere). The structure of the anomalies of vertical cells outside the Pacific region differ over the Western Indian Ocean and East Africa, South America and the Caribbean. The analysis of regional circulation response to the El Niño revealed that in the Northern Hemisphere the intensity of the response is comparable for two types of El Niño, while in the Southern Hemisphere the circulation anomalies are more pronounced during the El Niño Modoki. All atmosphere centers of actions under investigation were divided into four groups according to the character of circulation response to the two types of El Niño: 1 - centers of action with similar response to both types of El Niño; 2 - centers of action with different response to canonical and Modoki El Niño; 3 - centers of action, having significant correlations with only one type of El Niño; 4 - centers of action with no significant relationships with two types of El Niño. It is suggested that the difference in weather anomalies observed during the two types of El Niño are mostly associated to the circulation anomalies in the centers of action and in the vertical cells which differs between canonical and Modoki El Niño. References: 1. Ashok K., Behera S. K., Rao S. A., Weng H., Yamagata, T. El Nino Modoki and its possible teleconnection. J. Geophys. Res. 2007, 112, C11007, doi:10.1029/2006JC003798. 2. Kug, J.S., Jin F.F. and An S.I. Two types of El Niño events:Cold tongue El Niño and warm pool El Niño. // J. Clim., 2009, vol. 22, pp. 1499-1515. 3. Mo, K. C., Interdecadal modulation of the impact of ENSO on precipitation and temperature over the United States, J. Clim., 2010, 23, 3639-3656, doi:10.1175/2010JCLI3553.1. 4. Weng H., Behera

  6. Sequestration of Sr(II) By Calcium Oxalate - a Batch Uptake Study And EXAFS Analysis of Model Compounds And Reaction Products

    SciTech Connect

    Singer, D.M.; Johnson, S.B.; Catalano, J.G.; Farges, F.; Brown, G.E.; Jr.


    Calcium oxalate monohydrate (CaC{sub 2}O{sub 4}{center_dot}H{sub 2}O -- abbreviated as CaOx) is produced by two-thirds of all plant families, comprising up to 80 wt.% of the plant tissue and found in many surface environments. It is unclear, however, how CaOx in plants and soils interacts with metal ions and possibly sequesters them. This study examines the speciation of Sr(II){sub aq} following its reaction with CaOx. Batch uptake experiments were conducted over the pH range 4--10, with initial Sr solution concentrations, [Sr]{sub aq}, ranging from 1 x 10{sup -4} to 1 x 10{sup -3} M and ionic strengths ranging of 0.001--0.1 M, using NaCl as the background electrolyte. Experimental results indicate that Sr uptake is independent of pH and ionic strength over these ranges. After exposure of CaOx to Sr{sub aq} for two days, the solution Ca concentration, [Ca]{sup aq}, increased for all samples relative to the control CaOx suspension (with no Sr added). The amount of Sr{sub aq} removed from solution was nearly equal to the total [Ca]{sup aq} after exposure of CaOx to Sr. These results suggest that nearly 90% of the Sr is removed from solution to a solid phase as Ca is released into solution. We suggest that the other 10% is sequestered through surface adsorption on a solid phase, although we have no direct evidence for this. Extended X-ray absorption fine structure (EXAFS) spectroscopy was used to determine the molecular-level speciation of Sr in the reaction products. Deconvolutions of the Sr K-edge EXAFS spectra were performed to identify multi-electron excitation (MEE) features. MEE effects were found to give rise to low-frequency peaks in the Fourier transform before the first shell of oxygen atoms and do not affect EXAFS fitting results. Because of potential problems caused by asymmetric distributions of Sr-O distances when fitting Sr K-edge EXAFS data using the standard harmonic model, we also employed a cumulant expansion model and an asymmetric analytical model

  7. DUSEL Facility Cooling Water Scaling Issues

    SciTech Connect

    Daily, W D


    Precipitation (crystal growth) in supersaturated solutions is governed by both kenetic and thermodynamic processes. This is an important and evolving field of research, especially for the petroleum industry. There are several types of precipitates including sulfate compounds (ie. barium sulfate) and calcium compounds (ie. calcium carbonate). The chemical makeup of the mine water has relatively large concentrations of sulfate as compared to calcium, so we may expect that sulfate type reactions. The kinetics of calcium sulfate dihydrate (CaSO4 {center_dot} 2H20, gypsum) scale formation on heat exchanger surfaces from aqueous solutions has been studied by a highly reproducible technique. It has been found that gypsum scale formation takes place directly on the surface of the heat exchanger without any bulk or spontaneous precipitation in the reaction cell. The kinetic data also indicate that the rate of scale formation is a function of surface area and the metallurgy of the heat exchanger. As we don't have detailed information about the heat exchanger, we can only infer that this will be an issue for us. Supersaturations of various compounds are affected differently by temperature, pressure and pH. Pressure has only a slight affect on the solubility, whereas temperature is a much more sensitive parameter (Figure 1). The affect of temperature is reversed for calcium carbonate and barium sulfate solubilities. As temperature increases, barium sulfate solubility concentrations increase and scaling decreases. For calcium carbonate, the scaling tendencies increase with increasing temperature. This is all relative, as the temperatures and pressures of the referenced experiments range from 122 to 356 F. Their pressures range from 200 to 4000 psi. Because the cooling water system isn't likely to see pressures above 200 psi, it's unclear if this pressure/scaling relationship will be significant or even apparent. The most common scale minerals found in the oilfield include

  8. Nanomaterials for LightManagement in Electro-Optical Devices

    SciTech Connect

    Truong, Vo-Van; Singh, Jai; Tanemura, Sakae; Hu, Michael Z.


    . have presented their studies on the synthesis, characterization, and electrochromic applications of porous WO{sub 3} thin films with different nanocrystalline phases. Asymmetric type electrochromic devices have been constructed using hexagonal, monoclinic, and orthorhombic porous WO{sub 3} thin porous films, and their enhanced electrochromic functionality has been well demonstrated. The paper on smart materials by Chen et al. presents the synthesis of thermochromic W-doped VO{sub 2} (monoclinic/rutile) nanopowders using a novel and simple solution-based process as opposed to other conventional techniques such as excimer laser-assisted metal organic deposition and magnetron sputtering. This simple process is based on the reaction of ammonium metavanadate (NH{sub 4}VO{sub 3}) and oxalic acid dihydrate (C{sub 2}H{sub 2}O{sub 4} {center_dot} 2H{sub 2}O) followed by addition of appropriate ammonium tungstate (N{sub 5}H{sub 37}W{sub 6}O{sub 24} {center_dot} H{sub 2}O).

  9. Refractory Materials for Flame Deflector Protection System Corrosion Control: Refractory Ceramics Literature Survey

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina; Hintze, Paul E.; Parlier, Christopher R.; Curran, Jerome P.; Kolody, Mark; Perusich, Stephen; Whitten, Mary C.; Trejo, David; Zidek, Jason; Sampson, Jeffrey W.; Coffman, Brekke E.


    Ceramics can be defmed as a material consisting of hard brittle properties produced from inorganic and nonmetallic minerals made by firing at high temperatures. These materials are compounds between metallic and nonmetallic elements and are either totally ionic, or predominately ionic but having some covalent character. This definition allows for a large range of materials, not all applicable to refractory applications. As this report is focused on potential ceramic materials for high temperature, aggressive exposure applications, the ceramics reviewed as part of this report will focus on refractory ceramics specifically designed and used for these applications. Ceramic materials consist of a wide variety of products. Callister (2000) 1 characterized ceramic materials into six classifications: glasses, clay products, refractories, cements, abrasives, and advanced ceramics. Figure 1 shows this classification system. This review will focus mainly on refractory ceramics and cements as in general, the other classifications are neither applicable nor economical for use in large structures such as the flame trench. Although much work has been done in advanced ceramics over the past decade or so, these materials are likely cost prohibitive and would have to be fabricated off-site, transported to the NASA facilities, and installed, which make these even less feasible. Although the authors reviewed the literature on advanced ceramic refractories 2 center dot 3 center dot 4 center dot 5 center dot 6 center dot 7 center dot 8 center dot 9 center dot 10 center dot 11 center dot 12 after the review it was concluded that these materials should not be ' the focus of this report. A review is in progress on materials and systems for prefabricated refractory ceramic panels, but this review is focusing more on typical refractory materials for prefabricated systems, which could make the system more economically feasible. Refractory ceramics are used for a wide variety of applications