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Sample records for po dannym yamr

  1. Short-lived isomers in 192Po and 194Po

    NASA Astrophysics Data System (ADS)

    Andel, B.; Andreyev, A. N.; Antalic, S.; Heßberger, F. P.; Ackermann, D.; Hofmann, S.; Huyse, M.; Kalaninová, Z.; Kindler, B.; Kojouharov, I.; Kuusiniemi, P.; Lommel, B.; Nishio, K.; Page, R. D.; Sulignano, B.; Van Duppen, P.

    2016-06-01

    Isomeric states in 194Po and 192Po were studied at the velocity filter SHIP. The isotopes were produced in the fusion-evaporation reactions 141Pr(56Fe, p 2 n )194Po and 144Sm(51V, p 2 n )192Po . Several new γ -ray transitions were attributed to the isomers and γ -γ coincidences for both isomers were studied for the first time. The 459-keV transition earlier, tentatively proposed as de-exciting the isomeric level in 194Po, was replaced by a new 248-keV transition, and the spin of this isomer was reassigned from (11-) to (10-). The de-excitation of the (11-) isomeric level in 192Po by the 154-keV transition was confirmed and a parallel de-excitation by a 733-keV (E 3 ) transition to (8+) level of the ground-state band was suggested. Moreover, side feeding to the (4+) level of the ground-state band was proposed. The paper also discusses strengths of transitions de-exciting 11- isomers in neighboring Po and Pb isotopes.

  2. Production and decay spectroscopy of 192Po and 194Po

    NASA Astrophysics Data System (ADS)

    Andel, B.

    2015-10-01

    A γ-ray spectroscopy study of the (11-) isomers in 194Po and 192Po was performed at the velocity filter SHIP at GSI (Germany). Nuclei were produced in fusion-evaporation reactions and investigated in the detection set-up at the focal plane after the separator. Several new γ transitions were attributed to the isomers and detailed analysis of the first γ-γ coincidences for both isomers is being prepared. For the reaction 56Fe + 141Pr → 197At*, excitation functions for astatine and polonium isotopes were measured and compared with HIVAP calculations.

  3. Role of PO4 tetrahedron in LiFePO4 and FePO4 system.

    PubMed

    Zeng, Yuewu

    2015-06-01

    Using high resolution transmission electron microscopy with image simulation and Fourier analysis, the Li1- x FePO4 (x < 0.01), Li1- x FePO4 (x ∼ 0.5), and FePO4 particles, prepared by charging or discharging the 053048 electrochemical cells (thickness: 5 mm, width: 30 mm, height: 48 mm) and dismantled inside an Ar-filled dry box, were investigated. The high resolution images reveal: (1) the solid solution of Li1- x FePO4 (x < 0.01) contains some missing Li ions leading PO4 group distorted around M1 tunnel of the unit cell; (2) the texture of the particles of Li1- x FePO4 (x ∼0.5) has homogeneously distributed compositional domains of LiFePO4 and FePO4 resulting from spinodal decomposition which promote Li ion easily getting into the particle due to uphill diffusion, (3) the particles of FePO4 formed in charging have heavily distorted lattice and contain some isolated LiFePO4 , (4) interface between LiFePO4 and FePO4 and between amorphous and crystal region provides the lattice distortion of small polarons.

  4. Kinetics of neutralization of Po-218

    SciTech Connect

    Chu, K.D.

    1987-01-01

    In a well-defined experimental system the neutralization of polonium-218 ions was investigated as a function of the physical and chemical properties of the controlled composition atmosphere. The mobilities of Po/sup +/ and PoO/sub 2//sup +/ are determined by combining experimental results with a computer model of the system. Three neutralization mechanisms were individually studied. The small ion recombination rate has been found to be proportional to the square root of radon concentration. The electron scavenging mechanism is responsible for the neutralization of Po/sup +/ in NO/sub 2/ or H/sub 2/O in nitrogen. When PoO/sub 2//sup +/ is formed, the electron transfer mechanism dominates the neutralization process. The electron is transferred to PoO/sub 2//sup +/ from molecules with lower ionization potentials. The ionization potential of PoO/sub 2//sup +/ is also determined to be 10.44 +/- 0.05 eV.

  5. Ultrasonic-assisted synthesis of core-shell structure CePO4:Tb/GdPO4 and GdPO4/CePO4:Tb nanophosphors and their photoluminescence properties

    NASA Astrophysics Data System (ADS)

    Fan, Yao-yao; Hu, Zong-chao; Yang, Jian; Zhang, Chao; Zhu, Ling

    2013-02-01

    CePO4:Tb, CePO4:Tb/GdPO4, GdPO4/CePO4:Tb and (Ce, Tb, Gd)PO4 (4-8) nm × (35-73) nm sized nanobars with the hexagonal crystal system have been obtained by ultrasonic-assisted synthesis and characterized by X-ray diffraction (XRD), FT-IR spectrum, transmission electron microscopy (TEM), photoluminescence (PL). The shell thickness of CePO4:Tb/GdPO4 and GdPO4/CePO4:Tb core/shell structure is 1.04 nm and 1.10 nm respectively. Under ultraviolet excitation, these nanophosphors show Tb3+ characteristic emission, 5D4-7FJ (J = {6, 5, 4, 3}) and the fluorescence of CePO4:Tb/GdPO4 and GdPO4/CePO4:Tb increases superficially compared with CePO4:Tb and the co-precipitated (Ce, Tb, Gd)PO4. The photoluminescence intensity of CePO4:Tb/GdPO4 is 33 times, 7 times, 2 times as high as that of CePO4:Tb, GdPO4/CePO4:Tb and (Ce, Tb, Gd)PO4, respectively. It is worth mentioning that the increasing amount of intensity of CePO4:Tb/GdPO4 is double than that of GdPO4/CePO4:Tb. A possible formation mechanism for the fluorescent efficiency enhancement has been proposed. The results are helpful in developing effective phosphors and have potential applications in field emission display (FED) and plasma display panels (PDP).

  6. Redetermination of AgPO3

    PubMed Central

    Terebilenko, Katherina V.; Zatovsky, Igor V.; Ogorodnyk, Ivan V.; Baumer, Vyacheslav N.; Slobodyanik, Nikolay S.

    2011-01-01

    Single crystals of silver(I) polyphosphate(V), AgPO3, were prepared via a phospho­ric acid melt method using a solution of Ag3PO4 in H3PO4. In comparison with the previous study based on single-crystal Weissenberg photographs [Jost (1961 ▶). Acta Cryst. 14, 779–784], the results were mainly confirmed, but with much higher precision and with all displacement parameters refined anisotropically. The structure is built up from two types of distorted edge- and corner-sharing [AgO5] polyhedra, giving rise to multidirectional ribbons, and from two types of PO4 tetra­hedra linked into meandering chains (PO3)n spreading parallel to the b axis with a repeat unit of four tetra­hedra. The calculated bond-valence sum value of one of the two AgI ions indicates a significant strain of the structure. PMID:21522230

  7. Redetermination of AgPO(3).

    PubMed

    Terebilenko, Katherina V; Zatovsky, Igor V; Ogorodnyk, Ivan V; Baumer, Vyacheslav N; Slobodyanik, Nikolay S

    2011-02-09

    Single crystals of silver(I) polyphosphate(V), AgPO(3), were prepared via a phospho-ric acid melt method using a solution of Ag(3)PO(4) in H(3)PO(4). In comparison with the previous study based on single-crystal Weissenberg photographs [Jost (1961 ▶). Acta Cryst. 14, 779-784], the results were mainly confirmed, but with much higher precision and with all displacement parameters refined anisotropically. The structure is built up from two types of distorted edge- and corner-sharing [AgO(5)] polyhedra, giving rise to multidirectional ribbons, and from two types of PO(4) tetra-hedra linked into meandering chains (PO(3))(n) spreading parallel to the b axis with a repeat unit of four tetra-hedra. The calculated bond-valence sum value of one of the two Ag(I) ions indicates a significant strain of the structure.

  8. Redetermination of AgPO(3).

    PubMed

    Terebilenko, Katherina V; Zatovsky, Igor V; Ogorodnyk, Ivan V; Baumer, Vyacheslav N; Slobodyanik, Nikolay S

    2011-01-01

    Single crystals of silver(I) polyphosphate(V), AgPO(3), were prepared via a phospho-ric acid melt method using a solution of Ag(3)PO(4) in H(3)PO(4). In comparison with the previous study based on single-crystal Weissenberg photographs [Jost (1961 ▶). Acta Cryst. 14, 779-784], the results were mainly confirmed, but with much higher precision and with all displacement parameters refined anisotropically. The structure is built up from two types of distorted edge- and corner-sharing [AgO(5)] polyhedra, giving rise to multidirectional ribbons, and from two types of PO(4) tetra-hedra linked into meandering chains (PO(3))(n) spreading parallel to the b axis with a repeat unit of four tetra-hedra. The calculated bond-valence sum value of one of the two Ag(I) ions indicates a significant strain of the structure. PMID:21522230

  9. Metabolism of 210Po in rats: volatile 210Po from faeces.

    PubMed

    Sadi, Baki B; Li, Chunsheng; Wyatt, Heather; Bugden, Michelle; Wilkinson, Diana; Kramer, Gary

    2011-04-01

    The metabolic formation of volatile (210)Po species in a rat that was intravenously administered with (210)Po-citrate was investigated in this study. A slurry of the faecal sample was prepared in water and was bubbled with nitrogen gas in a closed system. The discharged gas was passed through a trapping device filled with liquid scintillation cocktail in order to capture any volatile (210)Po species. The amount of (210)Po trapped in the scintillation cocktail was measured by a liquid scintillation analyser that provided evidence of the presence of volatile (210)Po species in the faeces. The presence of volatile (210)Po in the faeces indicates that the metabolic formation of volatile (210)Po is likely to occur in the gut due to bacterial activity. The amount of volatile (210)Po species was compared with the daily faecal excretion of (210)Po. After 2 h of bubbling, the volatile (210)Po collected from the faeces sample was found to be between 1.0 and 1.7 % of the daily faecal excretion for the 4 d following (210)Po-citrate administration.

  10. Metabolism of 210Po in rats: volatile 210Po in excreta.

    PubMed

    Li, Chunsheng; Sadi, Baki; Wyatt, Heather; Bugden, Michelle; Priest, Nicholas; Wilkinson, Diana; Kramer, Gary H

    2010-07-01

    Polonium-210 ((210)Po) is one of the most toxic radionuclides and was used as a poison in the Alexander Litvinenko case. In this study of the metabolism of (210)Po in rats, volatile (210)Po in excreta was measured, filling a knowledge gap of the previous studies. Five rats were intravenously administrated with 2 kBq and another five with 10 kBq of (210)Po (citrate form). They were housed in a glass Metabowl system for 4 d following the administration. Volatile (210)Po from the excreta was collected in a trapping system filled with liquid scintillation cocktail and was measured by liquid scintillation counting. Results showed that the daily excretion of volatile (210)Po by the rats is in a very small percentage (0.002-0.009 %) of the administered amounts. However, if the administered amount is large, the excretion of volatile (210)Po can be significant.

  11. PO2 Cycling Reduces Diaphragm Fatigue by Attenuating ROS Formation

    PubMed Central

    Zuo, Li; Diaz, Philip T.; Chien, Michael T.; Roberts, William J.; Kishek, Juliana; Best, Thomas M.; Wagner, Peter D.

    2014-01-01

    Prolonged muscle exposure to low PO2 conditions may cause oxidative stress resulting in severe muscular injuries. We hypothesize that PO2 cycling preconditioning, which involves brief cycles of diaphragmatic muscle exposure to a low oxygen level (40 Torr) followed by a high oxygen level (550 Torr), can reduce intracellular reactive oxygen species (ROS) as well as attenuate muscle fatigue in mouse diaphragm under low PO2. Accordingly, dihydrofluorescein (a fluorescent probe) was used to monitor muscular ROS production in real time with confocal microscopy during a lower PO2 condition. In the control group with no PO2 cycling, intracellular ROS formation did not appear during the first 15 min of the low PO2 period. However, after 20 min of low PO2, ROS levels increased significantly by ∼30% compared to baseline, and this increase continued until the end of the 30 min low PO2 condition. Conversely, muscles treated with PO2 cycling showed a complete absence of enhanced fluorescence emission throughout the entire low PO2 period. Furthermore, PO2 cycling-treated diaphragm exhibited increased fatigue resistance during prolonged low PO2 period compared to control. Thus, our data suggest that PO2 cycling mitigates diaphragm fatigue during prolonged low PO2. Although the exact mechanism for this protection remains to be elucidated, it is likely that through limiting excessive ROS levels, PO2 cycling initiates ROS-related antioxidant defenses. PMID:25299212

  12. Characterization of the shark myelin Po protein.

    PubMed

    Rotenstein, L; Herath, K; Gould, R M; de Bellard, M E

    2008-01-01

    Myelin, the insulating sheath made by extensive plasma membrane wrapping, is dependent on the presence of highly adhesive molecules that keep the two sides of the membrane in tight contact. The Po glycoprotein (Po) is the major component of the peripheral nervous system (PNS) myelin of mammals. The exact role that Po protein has played in the evolution of myelin is still unclear, but several phylogenetic observations suggest that it is a crucial component in the development of myelin as a multi-lamellar membrane structure. Sharks, which appeared in the fossil record about 400 million years ago, are the first fully myelinated organisms. In this study we investigated the expression pattern of shark myelin Po to suggest a way it might have played a role in the evolution of myelin in the central nervous system. We found that sharks have more than two isoforms (32, 28 and 25 kD), and that some of these might not be fully functional because they lack the domains known for Po homophilic adhesion.

  13. Transcutaneous pO2 of volunteers during hyperbaric oxygenation.

    PubMed

    Huch, A; Huch, R; Hollmann, G; Hockerts, T; Keller, H P; Seiler, D; Sadzek, J; Lübbers, D W

    1977-01-01

    Continuous transcutaneous pO2 measurements (tcPO2 measurements) were performed in healthy volunteers who were breathing air and oxygen under hyperbaric conditions (max. 4 ata). The results show a close correlation of PO2 values measured by the noninvasive method, in blood from discret arterial punctures, chamber PO2, respectively, the PO2 of the inspiratory gas mixture which was checked up to maximal values of 2,200 mm Hg. The PO2 in the arterial blood samples was measured immediately after the puncture insight the hyperbaric chamber using a specially designed through electrode. PMID:610774

  14. BiPO4 photocatalyst employing synergistic action of Ag/Ag3PO4 nanostructure and graphene nanosheets

    NASA Astrophysics Data System (ADS)

    Mohaghegh, N.; Rahimi, E.

    2016-06-01

    Graphene-supported BiPO4/Ag/Ag3PO4 photocatalyst has been fabricated by simple hydrothermal and impregnation reaction. In BiPO4/Ag/Ag3PO4 based on Reduced Graphene Oxide (RGO), this network renders numerous pathways for rapid mass transport, strong adsorption and multireflection of incident light; meanwhile, the interface between BiPO4/Ag/Ag3PO4 and RGO increases the active sites and electron transfer rate. BiPO4/Ag/Ag3PO4 based on RGO noticeably exhibited high photocatalytic activity than that of BiPO4/Ag/Ag3PO4 and P25 under visible light irradiation for cationic dye (Rhodamine B), anionic dye (methyl orange) and 4-chlorophenol (4-CP) as a neutral pollutant, which are usually difficult to be degraded over the other catalysts. This enhanced photocatalytic activity of Graphene-supported BiPO4/Ag/Ag3PO4 for all pollutants could be mainly ascribed to the reinforced charge transfer from BiPO4/Ag/Ag3PO4 to RGO, which suppresses the recombination of electron/hole pairs. Besides that, this photocatalyst can be used repetitively with a high photocatalytic activity and no apparent loss of activity occurs. The results reveal that the RGO nanosheets work as a photocatalyst promoter during the photocatalytic reaction, leading to an improved photocatalytic activity.

  15. Electronic Properties of LiFePO4 and Li doped LiFePO4

    SciTech Connect

    Zhuang, G.V.; Allen, J.L.; Ross, P.N.; Guo, J.-H.; Jow, T.R.

    2005-06-28

    The potential use of different iron phosphates as cathodematerials in lithium-ion batteries has recently been investigated.1 Oneof the promising candidates is LiFePO4. This compound has severaladvantages in comparison to the state-of-the-art cathode material incommercial rechargeable lithium batteries. Firstly, it has a hightheoretical capacity (170 mAh/g). Secondly, it occurs as mineraltriphylite in nature and is inexpensive, thermally stable, non-toxic andnon-hygroscopic. However, its low electronic conductivity (~;10-9 S/cm)results in low power capability. There has been intense worldwideresearch activity to find methods to increase the electronic conductivityof LiFePO4, including supervalent ion doping,2 introducingnon-carbonaceous network conduction3 and carbon coating, and theoptimization of the carbon coating on LiFePO4 particle surfaces.4Recently, the Li doped LiFePO4 (Li1+xFe1-xPO4) synthesized at ARL hasyield electronic conductivity increase up to 106.5 We studied electronicstructure of LiFePO4 and Li doped LiFePO4 by synchrotron based soft X-rayemission (XES) and X-ray absorption (XAS) spectroscopies. XAS probes theunoccupied partial density of states, while XES the occupied partialdensity of states. By combining XAS and XES measurements, we obtainedinformation on band gap and orbital character of both LiFePO4 and Lidoped LiFePO4. The occupied and unoccupied oxygen partial density ofstates (DOS) of LiFePO4 and 5 percent Li doped LiFePO4 are presented inFig. 1. Our experimental results clearly indicate that LiFePO4 has wideband gap (~; 4 eV). This value is much larger than what is predicted byDFT calculation. For 5 percent Li doped LiFePO4, a new doping state wascreated closer to the Fermi level, imparting p-type conductivity,consistent with thermopower measurement. Such observation substantiatesthe suggestion that high electronic conductivity in Li1.05Fe0.95 PO4 isdue to available number of charge carriers in the material. Furthermore,Hall effect

  16. Shape Coexistence in Neutron Deficient Po Nuclei

    SciTech Connect

    Helariutta, K.; Cocks, J.F.C.; Enqvist, T.; Greenlees, P.T.; Jones, P.; Julin, R.; Juutinen, S.; Jamsen, P.; Kankaanpaa, H.; Kettunen, H.; Kuiusiniemi, P.; Leino, M.; Muikkui, M.; Piiparinen, M.; Rahkila, P.; Savelius, A.; Trzaska, W.H.; Tormanen, S.; Uusitalo, J.; Allatt, R.G.; Butler, P.A.; Page, R.D.; Kapusta, M.

    1999-12-31

    The excited levels in {sup 192-195}Po have been studied using the recoil-decay tagging method. New levels have been identified. The data are in accordance with the scheme of the coexisting spherical and deformed intruder structures crossing each other with N<112.

  17. Shape coexistence in neutron deficient Po nuclei

    SciTech Connect

    Helariutta, K.; Cocks, J. F. C.; Enqvist, T.; Greenlees, P. T.; Jones, P.; Julin, R.; Juutinen, S.; Jaemsen, P.; Kankaanpaeae, H.; Kettunen, H.; Kuusiniemi, P.; Leino, M.; Muikku, M.; Piiparinen, M.; Rahkila, P.; Savelius, A.; Trzaska, W. H.; Toermaenen, S.; Uusitalo, J.; Allatt, R. G.

    1999-11-16

    The excited levels in {sup 192-195}Po have been studied using the recoil-decay tagging method. New levels have been identified. The data are in accordance with the scheme of the coexisting spherical and deformed intruder structures crossing each other with N<112.

  18. Electronic Properties of LiFePO4 and Li doped LiFePO4

    SciTech Connect

    Allen, J.L.; Zhuang, G.V.; Ross, P.N.; Guo, J.-H.; Jow, T.R.

    2006-05-31

    LiFePO{sub 4} has several potential advantages in comparison to the transition metal oxide cathode materials used in commercial lithium-ion batteries. However, its low intrinsic electronic conductivity ({approx} 10{sup -9} S/cm) is problematic. We report here a study by soft x-ray absorption/emission spectroscopy of the electronic properties of undoped LiFePO{sub 4} and Li-doped LiFePO{sub 4} in which Li{sup +} ions are substituted for Fe{sup 2+} ions in an attempt to increase the intrinsic electronic conductivity. The conductivities of the Li{sub 1+x}Fe{sub 1-x}PO{sub 4} samples were, however, essentially unchanged from that of the undoped LiFePO{sub 4}. Nonetheless, evidence for changing the electronic properties of LiFePO{sub 4} by doping with excess Li+ was observed by the XAS/XES spectroscopy. New pre-edge features the O-1s XAS spectrum of Li{sub 1.05}Fe{sub 0.95}PO4 is a direct indication that the charge compensation for substitution of Fe{sup 2+} by Li{sup +} resides in the unoccupied O-2p orbitals. A charge transfer (CT) excitation was also observed in the doped material implying that the unoccupied O-2p orbitals created by doping are strongly hybridized with unoccupied Fe-3d orbitals of neighboring sites. However, the strong covalent bonding within the (PO{sub 4}){sup 3-} anions and the large separation of the Fe cations means that the charge created by doping is not delocalized in the manner of electrons or holes in a semiconductor.

  19. 210Po microsphere radiological design for tumor vascular disruption

    PubMed Central

    2015-01-01

    The feasibility of disrupting a tumor’s vascular structure using 210Po microspheres is investigated using standard ion and photon absorbed dose methodologies. Calculated absorbed dose profiles for 210Po alpha particles are sufficient to disrupt a tumor’s arteriole structure while minimizing the dose outside the blood vessel wall. 210Po photons contribute minimal dose to healthy tissue. The requisite activity of 210Po to facilitate vascular disruption is calculated. PMID:26290796

  20. 49 CFR 604.36 - Powers of a PO.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 7 2014-10-01 2014-10-01 false Powers of a PO. 604.36 Section 604.36 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL TRANSIT ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CHARTER SERVICE Hearings § 604.36 Powers of a PO. A PO may: (a) Give notice...

  1. 49 CFR 604.46 - Recommended decision by a PO.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 7 2013-10-01 2013-10-01 false Recommended decision by a PO. 604.46 Section 604... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CHARTER SERVICE Hearings § 604.46 Recommended decision by a PO. (a) The PO shall issue a recommended decision based on the record developed during the proceeding...

  2. 49 CFR 604.46 - Recommended decision by a PO.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 7 2012-10-01 2012-10-01 false Recommended decision by a PO. 604.46 Section 604... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CHARTER SERVICE Hearings § 604.46 Recommended decision by a PO. (a) The PO shall issue a recommended decision based on the record developed during the proceeding...

  3. 49 CFR 604.46 - Recommended decision by a PO.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Recommended decision by a PO. 604.46 Section 604... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CHARTER SERVICE Hearings. § 604.46 Recommended decision by a PO. (a) The PO shall issue a recommended decision based on the record developed during the proceeding...

  4. 49 CFR 604.36 - Powers of a PO.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 7 2011-10-01 2011-10-01 false Powers of a PO. 604.36 Section 604.36 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL TRANSIT ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CHARTER SERVICE Hearings. § 604.36 Powers of a PO. A PO may: (a) Give notice...

  5. 49 CFR 604.36 - Powers of a PO.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Powers of a PO. 604.36 Section 604.36 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL TRANSIT ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CHARTER SERVICE Hearings. § 604.36 Powers of a PO. A PO may: (a) Give notice...

  6. 49 CFR 604.46 - Recommended decision by a PO.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 7 2014-10-01 2014-10-01 false Recommended decision by a PO. 604.46 Section 604... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CHARTER SERVICE Hearings § 604.46 Recommended decision by a PO. (a) The PO shall issue a recommended decision based on the record developed during the proceeding...

  7. 49 CFR 604.36 - Powers of a PO.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 7 2013-10-01 2013-10-01 false Powers of a PO. 604.36 Section 604.36 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL TRANSIT ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CHARTER SERVICE Hearings § 604.36 Powers of a PO. A PO may: (a) Give notice...

  8. 49 CFR 604.46 - Recommended decision by a PO.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 7 2011-10-01 2011-10-01 false Recommended decision by a PO. 604.46 Section 604... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CHARTER SERVICE Hearings. § 604.46 Recommended decision by a PO. (a) The PO shall issue a recommended decision based on the record developed during the proceeding...

  9. 49 CFR 604.36 - Powers of a PO.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 7 2012-10-01 2012-10-01 false Powers of a PO. 604.36 Section 604.36 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL TRANSIT ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CHARTER SERVICE Hearings § 604.36 Powers of a PO. A PO may: (a) Give notice...

  10. Half-life of /sup 218/Po

    SciTech Connect

    Potapov, V.G.; Soloshenkov, P.S.

    1986-10-01

    The decay of Po 218 is accompanied by the emission of 6.00-MeV alpha particles. The most suitable method for studying it is the alphaspectrometric method. To generate radon, the source for RaA, the authors used a preparation of Ra 226 with a high degree of purity. Targets were prepared for measuring the half-life on a radon setup. Approximately 30 sec after holding in a radon atmosphere the target was placed with the polonium deposited on it into a vacuum chamber. It was noted that the intensity of the peak at 6.70 MeV decreases at the same rate as the decay of Po 218, and the ratio of the intensities of their peaks was equal to 0.037 +/- 0.007%. The spectra (alpha was analyzed on an LP-4900 analyzer. The values of the half-life that were obtained are in good agreement with the values obtained previously.

  11. PoET: Polarimeters for Energetic Transients

    NASA Technical Reports Server (NTRS)

    McConnell, Mark; Barthelmy, Scott; Hill, Joanne

    2008-01-01

    This presentation focuses on PoET (Polarimeters for Energetic Transients): a Small Explorer mission concept proposed to NASA in January 2008. The principal scientific goal of POET is to measure GRB polarization between 2 and 500 keV. The payload consists of two wide FoV instruments: a Low Energy Polarimeter (LEP) capable of polarization measurements in the energy range from 2-15 keV and a high energy polarimeter (Gamma-Ray Polarimeter Experiment - GRAPE) that will measure polarization in the 60-500 keV energy range. Spectra will be measured from 2 keV up to 1 MeV. The PoET spacecraft provides a zenith-pointed platform for maximizing the exposure to deep space. Spacecraft rotation will provide a means of effectively dealing with systematics in the polarization response. PoET will provide sufficient sensitivity and sky coverage to measure statistically significant polarization for up to 100 GRBs in a two-year mission. Polarization data will also be obtained for solar flares, pulsars and other sources of astronomical interest.

  12. Solid Solution Phases in the Olivine-Type LiMnPO4/MnPO4 System

    SciTech Connect

    Chen, Guoying; Richardson, Thomas J.

    2009-04-07

    Nonstoichiometry is reported in the LiMnPO{sub 4}/MnPO{sub 4} system for the first time. As lithium is removed from crystalline LiMnPO{sub 4} by chemical or electrochemical methods, the resulting two phase mixture consists of stoichiometric LiMnPO{sub 4} and a delithiated phase, Li{sub y}MnPO{sub 4}, whose lattice parameters depend upon the global extent of delithiation and on the crystalline domain size of the delithiated phase. This behavior is reproduced during electrochemical insertion of lithium. Again, no evidence for nonstoichiometry was found in the vicinity of LiMnPO{sub 4}. Attempts to create single phase solid solutions by heating mixtures of the two phases failed due to the thermal instability of Li{sub y}MnPO{sub 4}.

  13. Production and decay spectroscopy of {sup 192}Po and {sup 194}Po

    SciTech Connect

    Andel, B.

    2015-10-15

    A γ-ray spectroscopy study of the (11{sup −}) isomers in {sup 194}Po and {sup 192}Po was performed at the velocity filter SHIP at GSI (Germany). Nuclei were produced in fusion-evaporation reactions and investigated in the detection set-up at the focal plane after the separator. Several new γ transitions were attributed to the isomers and detailed analysis of the first γ-γ coincidences for both isomers is being prepared. For the reaction {sup 56}Fe + {sup 141}Pr → {sup 197}At*, excitation functions for astatine and polonium isotopes were measured and compared with HIVAP calculations.

  14. Assessment of ²¹⁰Po in Italian diet.

    PubMed

    Meli, Maria Assunta; Desideri, Donatella; Roselli, Carla; Feduzi, Laura

    2014-07-15

    This research was dedicated to the study, in the Italian daily diet, of the background activity concentration of (210)Po, a radionuclide with a high radiotoxicity. (210)Po was determined by alpha spectrometry. For food products of vegetable origin, the (210)Po activity concentration follows the trend: leafy vegetable>flour>rice>fruits>pasta>other vegetables>fruit vegetable; for those of animal origin: eggs>cheese>milk. The (210)Po activity concentration was also compared with that found by the same authors in meat, sea food, water and beverages in a previous study. The committed effective doses to individuals of three population groups (infants, children and adults) were 379, 222 and 151 μSv y(-1), respectively. The intake of foods of marine origin contributed about 67% of the total dose due to (210)Po ingestion. The effective dose, from (210)Po ingested by total diet, accounts for only 5-12% of the natural radiation exposure in Italy.

  15. Assessment of ²¹⁰Po in Italian diet.

    PubMed

    Meli, Maria Assunta; Desideri, Donatella; Roselli, Carla; Feduzi, Laura

    2014-07-15

    This research was dedicated to the study, in the Italian daily diet, of the background activity concentration of (210)Po, a radionuclide with a high radiotoxicity. (210)Po was determined by alpha spectrometry. For food products of vegetable origin, the (210)Po activity concentration follows the trend: leafy vegetable>flour>rice>fruits>pasta>other vegetables>fruit vegetable; for those of animal origin: eggs>cheese>milk. The (210)Po activity concentration was also compared with that found by the same authors in meat, sea food, water and beverages in a previous study. The committed effective doses to individuals of three population groups (infants, children and adults) were 379, 222 and 151 μSv y(-1), respectively. The intake of foods of marine origin contributed about 67% of the total dose due to (210)Po ingestion. The effective dose, from (210)Po ingested by total diet, accounts for only 5-12% of the natural radiation exposure in Italy. PMID:24594158

  16. Collectivity of {sup 196}Po at low spin

    SciTech Connect

    Grahn, T.; Page, R. D.; Dewald, A.; Jolie, J.; Melon, B.; Pissulla, Th.; Greenlees, P. T.; Jakobsson, U.; Jones, P.; Julin, R.; Juutinen, S.; Ketelhut, S.; Leino, M.; Nyman, M.; Peura, P.; Rahkila, P.; Saren, J.; Scholey, C.; Sorri, J.; Uusitalo, J.

    2009-07-15

    Absolute electromagnetic transition probabilities in {sup 196}Po have been measured using the recoil distance Doppler-shift technique. The lifetimes of the three lowest yrast states in {sup 196}Po were extracted from singles {gamma}-ray spectra by using the recoil-decay tagging method. In addition, configuration mixing calculations of angular momentum projected mean-field states have been carried out for {sup 196}Po. The present study sheds light on the onset of collectivity and mixing of competing structures in neutron-deficient Po nuclei.

  17. Effect of Ag+ and PO43‑ ratios on the microstructure and photocatalytic activity of Ag3PO4

    NASA Astrophysics Data System (ADS)

    Qin, Jiaqian; Zhang, Xinyu; Yang, Chengwu; Song, Aijun; Zhang, Bing; Rajendran, Saravanan; Ma, Mingzhen; Liu, Riping

    2016-09-01

    In this work, the catalyst silver phosphate (Ag3PO4) with different initial ratios of Ag+ and PO43‑ in aqueous solution was synthesized by a simple precipitation method from AgNO3 and NH4H2PO4 which were used as the precursor. After that, the prepared samples were characterized by different techniques such as field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), UV-visible diffuse reflectance spectroscopy (UV-DRS) and decomposition evolution of rhodamine B (RhB) solution. The results indicate that the initial ratios of Ag+/PO43‑ in aqueous solution can modify the morphology and also it can significantly affect the photocatalytic performance. During photocatalytic process, the rich Ag+ ion Ag3PO4 can form the surface plasmon resonance (SPR) of Ag nanoparticles, which inhibit the reduction of Ag3PO4 resulting in higher photocatalytic activity and stability.

  18. Studies of {sup 194,195,197}Po

    SciTech Connect

    Carpenter, M.P.; Ahmad, I.; Crowell, B.

    1995-08-01

    The energy systematics of low-lying polonium states show sudden changes near N = 114. The observed drops in the low-lying levels of {sup 196,198}Po relative to the heavier isotopes indicate significant changes in the underlying structure of these nuclei. It is thought that this change is due to the onset of vibrational collectivity brought about by the quadrupole interaction between neutron and proton-pairs. In order to extend the Po systematics even further, we measured, for the first time, states in {sup 194,195,197}Po using the {sup 28}Si + {sup 170}Yb reaction at a beam energy of 142 MeV. The beam was supplied by ATLAS, and the data were taken with 10 Compton-suppressed Ge detectors placed at the target position of the Fragment Mass Analyzer. Preliminary level schemes were constructed for {sup 194,195,197}Po based on {gamma}-{gamma} and {gamma}-FMA coincidences. The results for {sup 194}Po show that the 2{sup +} - 0{sup +} transition energy decreased in energy by 140 keV relative to {sup 196}Po suggesting that this nucleus moved beyond the vibrational limit to more collective motion. An extrapolation of the systematics predicts that the 2{sup +} energy could drop another 140 keV between {sup 194}Po and {sup 192}Po which would indicate the onset of rotational motion. Currently, we have an approved experiment to investigate the decay of yrast isomers in {sup 194}Po which will allow us to (1) confirm our earlier level scheme of {sup 194}Po, and (2) assess the experimental conditions needed for a future study of {sup 192}Po.

  19. Renal threshold phosphate concentration (TmPO4/GFR).

    PubMed Central

    Kruse, K; Kracht, U; Göpfert, G

    1982-01-01

    The ratio of maximum rate of renal tubular reabsorption of phosphate to glomerular filtration rate (TmPO4/GFR) was determined in 546 schoolchildren, aged between 6 and 17.9 years, using the nomogram of Walton and Bijvoet.1 TmPO4/GFR correlated with chronological age in girls and boys and in each remained significantly higher than in adults. TmPO4/GFR in the children correlated neither with fasting serum immunoreactive calcitonin and parathyroid hormone levels nor with the urinary cyclic AMP excretion. The study showed a parallel decrease in TmPO4/GFR, excretion of total hydroxyproline and serum alkaline phosphatase activities after puberty, with a significant relationship of both these indices of bone turnover to TmPO4/GFR values. This indicates that the high renal phosphate threshold of children may be an important factor for bone mineralisation by providing high extracellular inorganic phosphate concentrations during normal growth. PMID:6280622

  20. Transport properties of LiCoPO4 and Fe-substituted LiCoPO4

    NASA Astrophysics Data System (ADS)

    Allen, Jan L.; Thompson, Travis; Sakamoto, Jeff; Becker, Collin R.; Jow, T. Richard; Wolfenstine, Jeff

    2014-05-01

    LiCoPO4 is a promising cathode material to enable high energy, abuse tolerant Li-ion batteries. However, LiCoPO4 has relatively poor electronic conductivity which may be improved by chemical substitution. In this work, the ionic and electronic conductivities of dense, polycrystalline LiCoPO4 and Fe2+/Fe3+-substituted LiCoPO4 (Li1-xCo0.9Fe0.1PO4) are measured and compared. Both materials are predominantly ionic conductors with relatively good bulk ionic and relatively poor electronic conductivities. Li1-xCo0.9Fe0.1PO4 exhibits both higher bulk ionic and electronic conductivity. The increased bulk ionic conductivity of Li1-xCo0.9Fe0.1PO4 is believed to originate mainly from extra Li vacancies and the increased electronic conductivity is believed to originate mainly from creating more mobile hole polarons compared to LiCoPO4 as a result of Fe2+/Fe3+ substitution.

  1. Na(7)Mg(13)Nd(PO(4))(12).

    PubMed

    Jerbi, Hasna; Hidouri, Mourad; Mongi, Ben Amara

    2012-06-01

    Investigations of the quasi-ternary system Na(3)PO(4)-Mg(3)(PO(4))(2)-NdPO(4) allowed us to obtain the new phosphate hepta-sodium trideca-magnesium neodymium dodeca-kis-phosphate, Na(7)Mg(13)Nd(PO(4))(12), by applying a flux method. The crystal structure is isotypic with that of the previously reported Na(7)Mg(13)Ln(PO(4))(12) (Ln = Eu, La) compounds. It consists of a complex three-dimensional framework built up from an NdO(8) polyhedron (m symmetry), an MO(6) octa-hedron statistically occupied by M = Mg and Na, and eight MgO(x) (x = 5, 6) polyhedra (four with site symmetry m), linked either directely by sharing corners, edges and faces, or by one of the eight unique PO(4) tetra-hedra through common corners. Two of the PO(4) tetra-hedra are statisticaly disordered over a mirror plane. The whole structure can be described as resutling from an assembly of two types of structural units, viz [Mg(4)MP(4)O(22)](∞) (2) layers extending parallel to (100) and stacked along [100], and [Mg(4)NdP(4)O(36)](∞) (1) undulating chains running along the [010] direction. The six different Na(+) cations (five with site symmetry m and one with 0.5 occupancy) are situated in six distinct cavities delimited by the framework. The structure was refined from data of a racemic twin.

  2. Biogeochemical factors affecting the presence of 210Po in groundwater

    USGS Publications Warehouse

    Seiler, R.L.; Stillings, L.L.; Cutler, N.; Salonen, L.; Outola, I.

    2011-01-01

    The discovery of natural 210Po enrichment at levels exceeding 500 mBq/L in numerous domestic wells in northern Nevada, USA, led to a geochemical investigation of the processes responsible for its mobilization. 210Po activities in 63 domestic and public-supply wells ranged from below 1 mBq/L to 6590 ± 590 mBq/L, among the highest reported levels in the USA. There is little spatial or depth variability in 210Pb activity in study-area sediments and mobilization of a few percent of the 210Po in the sediments would account for all of the 210Po in water. Stable-isotope measurements indicate SO4 reduction has occurred in all 210Po contaminated wells. Sulfide species are not accumulating in the groundwater in much of Lahontan Valley, probably because of S cycling involving microbial SO4 reduction, abiotic oxidation of H2S to S0 by Mn(IV), followed by microbial disproportionation of S0 to H2S and SO4. The high pH, Ca depletion, MnCO3 saturation, and presence of S0 in Lahontan Valley groundwater may be consequences of the anaerobic S cycling. Consistent with data from naturally-enriched wells in Florida, 210Po activities begin to decrease when aqueous sulfide species begin to accumulate. This may be due to formation and precipitation of PoS, however, Eh–pH diagrams suggest PoS would not be stable in study-area groundwater. An alternative explanation for the study area is that H2S accumulation begins when anaerobic S cycling stops because Mn oxides are depleted and their reduction is no longer releasing 210Po. Common features of 210Po-enriched groundwater were identified by comparing the radiological and geochemical data from Nevada with data from naturally-enriched wells in Finland, and Florida and Maryland in the USA. Values of pH ranged from 9 in Nevada wells, indicating that pH is not critical in determining whether 210Po is present. Where U is present in the sediments, the data suggest 210Po levels may be elevated in aquifers with (1) SO4-reducing waters with low H2S

  3. Muon spin relaxation study of Zr(H2PO4)(PO4).2H2O.

    PubMed

    Clayden, Nigel J; Cottrell, Stephen P

    2006-07-14

    Muon spin relaxation has been used to study the muon dynamics in the layered zirconium phosphate Zr(H(2)PO(4))(PO(4)).2H(2)O as a function of temperature. Radiofrequency decoupling was used to establish the origin of the local dipolar field as coupling with (1)H spins. Muons were trapped at two sites, one identified as HMuO and the other consistent with PO-Mu on the basis of their zero-field second moments. Although a small decrease in the local nuclear dipolar field was seen with temperature, the muons remained essentially static over the temperature range 20-300 K.

  4. K3Ga2(PO4)3 and Na3Ga(PO4)2.

    PubMed

    Beaurain, M; Astier, R; van der Lee, A; Armand, P

    2008-01-01

    The structures of tripotassium digallium tris(phosphate), K3Ga2(PO4)3, and trisodium gallium bis(phosphate), Na3Ga(PO4)2, have different irregular one-dimensional alkali ion-containing channels along the a axis of the orthorhombic and triclinic unit cells, respectively. The anionic subsystems consist of vortex-linked PO4 tetrahedra and GaO4 tetrahedra or GaO5 trigonal bipyramids in the first and second structure, respectively. PMID:18216425

  5. Polonium 210Po in the phytobenthos from Puck Bay.

    PubMed

    Skwarzec, B; Ulatowski, J; Strumińska, D I; Falandysz, J

    2003-04-01

    The aim of the work was to determine the 210Po content in phytobenthos species (seaweeds and angiosperms) from Puck Bay (southern Baltic). Alpha spectrometry was used to measure and calculate the activities and concentrations of polonium 210Po in the phytobenthos. The activity of 210Po in Puck Bay waters was determined to estimate the bioconcentration factors (BCF) of these plants. The 210Po concentration in water was estimated at 0.25 mBq dm(-3). The lowest polonium concentration in the phytobenthos was found in Cladophora rupestris (0.12 Bq kg(-1) wet wt.), the highest in Chara crinita (1.12 Bq kg(-1) wet wt.). Polonium is accumulated in these phytobenthos species; the bioconcentration factors (BCF) ranged from 450 to 4400.

  6. Search for mixed-symmetry states in 212Po

    NASA Astrophysics Data System (ADS)

    Kocheva, D.; Rainovski, G.; Jolie, J.; Pietralla, N.; Stahl, C.; Petkov, P.; Blazhev, A.; Hennig, A.; Astier, A.; Braunroth, Th.; Cortes, L.; Dewald, A.; Djongolov, M.; Fransen, C.; Gladnishki, K.; Karayonchev, V.; Litzinger, J.; Müller-Gatermann, C.; Scheck, M.; Scholz, Ph.; Schramm, C.; Tölle, P.; Werner, V.; Witt, W.; Wölk, D.; Van Isacker, P.

    2016-06-01

    In this work we present an experiment dedicated to searching for quarupole- collective isovector valence-shell excitation — the states with so-called mixed proton-neutron symmetry (MSSs), in the nucleus 212Po. The states of interest were populated and studied by an α-transfer reaction. The experiment provides indication for existence of one-phonon MSS in the nucleus 212Po which is the first experimentally identified MSS in the region around double magic nucleus 208Pb.

  7. Relational Aggression in Children with Preschool Onset (PO) Psychiatric Disorders

    PubMed Central

    Belden, Andy C.; Gaffrey, Michael S.; Luby, Joan L.

    2012-01-01

    Objective The role of preschool onset (PO) psychiatric disorders as correlates and/or risk factors for relational aggression during kindergarten or 1st grade was tested in a sample of N = 146 preschool-age children (3 to 5.11). Method Axis-I diagnoses and symptom scores were derived using the Preschool Age Psychiatric Assessment. Children’s roles in relational aggression as aggressor, victim, aggressive-victim, or non-aggressor/non-victim were determined at preschool and again 24 months later at elementary school entry. Results Preschoolers diagnosed with PO-psychiatric disorders were 3 times as likely as the healthy preschoolers to be classified aggressors, victims, or aggressive-victims. Children diagnosed with PO-disruptive, depressive, and/or anxiety disorders were at least 6 times as likely as children without PO-psychiatric disorders to become aggressive-victims during elementary school after covarying for other key risk factors. Conclusions Findings suggested that PO-psychiatric disorders differentiated preschool and school-age children’s roles in relational aggression based on teacher-report. Recommendations for future research and preventative intervention aimed at minimizing the development of relational aggression in early childhood by identifying and targeting PO-psychiatric disorders are made. PMID:22917202

  8. Lifetimes of (214)Po and (212)Po measured with Counting Test Facility at Gran Sasso National Laboratory.

    PubMed

    Miramonti, L; Bellini, G; Benziger, J; Bick, D; Bonfini, G; Bravo, D; Buizza Avanzini, M; Caccianiga, B; Cadonati, L; Calaprice, F; Carraro, C; Cavalcante, P; Chavarria, A; Chubakov, V; D'Angelo, D; Davini, S; Derbin, A; Etenko, A; Fomenko, K; Franco, D; Galbiati, C; Gazzana, S; Ghiano, C; Giammarchi, M; Göger-Neff, M; Goretti, A; Grandi, L; Guardincerri, E; Hardy, S; Ianni, Aldo; Ianni, Andrea; Kobychev, V; Korablev, D; Korga, G; Koshio, Y; Kryn, D; Laubenstein, M; Lewke, T; Lissia, M; Litvinovich, E; Loer, B; Lombardi, F; Lombardi, P; Ludhova, L; Machulin, I; Manecki, S; Maneschg, W; Mantovani, F; Manuzio, G; Meindl, Q; Meroni, E; Misiaszek, M; Montanari, D; Mosteiro, P; Muratova, V; Nisi, S; Oberauer, L; Obolensky, M; Ortica, F; Otis, K; Pallavicini, M; Papp, L; Perasso, L; Perasso, S; Pocar, A; Ranucci, G; Razeto, A; Re, A; Romani, A; Rossi, N; Sabelnikov, A; Saldanha, R; Salvo, C; Schönert, S; Simgen, H; Skorokhvatov, M; Smirnov, O; Sotnikov, A; Sukhotin, S; Suvorov, Y; Tartaglia, R; Testera, G; Vignaud, D; Vogelaar, R B; von Feilitzsch, F; Winter, J; Wojcik, M; Wright, A; Wurm, M; Xhixha, G; Xu, J; Zaimidoroga, O; Zavatarelli, S; Zuzel, G

    2014-12-01

    The decays of (214)Po into (210)Pb and of (212)Po into (208)Pb tagged by the previous decays from (214)Bi and (212)Bi have been studied inserting quartz vials inside the Counting Test Facility (CTF) at the underground laboratory in Gran Sasso (LNGS). We find that the mean lifetime of (214)Po is (236.00 ± 0.42(stat) ± 0.15(syst)) μs and that of (212)Po is (425.1 ± 0.9(stat) ± 1.2(syst)) ns. Our results are compatible with previous measurements, have a much better signal to background ratio, and reduce the overall uncertainties.

  9. Lifetimes of (214)Po and (212)Po measured with Counting Test Facility at Gran Sasso National Laboratory.

    PubMed

    Miramonti, L; Bellini, G; Benziger, J; Bick, D; Bonfini, G; Bravo, D; Buizza Avanzini, M; Caccianiga, B; Cadonati, L; Calaprice, F; Carraro, C; Cavalcante, P; Chavarria, A; Chubakov, V; D'Angelo, D; Davini, S; Derbin, A; Etenko, A; Fomenko, K; Franco, D; Galbiati, C; Gazzana, S; Ghiano, C; Giammarchi, M; Göger-Neff, M; Goretti, A; Grandi, L; Guardincerri, E; Hardy, S; Ianni, Aldo; Ianni, Andrea; Kobychev, V; Korablev, D; Korga, G; Koshio, Y; Kryn, D; Laubenstein, M; Lewke, T; Lissia, M; Litvinovich, E; Loer, B; Lombardi, F; Lombardi, P; Ludhova, L; Machulin, I; Manecki, S; Maneschg, W; Mantovani, F; Manuzio, G; Meindl, Q; Meroni, E; Misiaszek, M; Montanari, D; Mosteiro, P; Muratova, V; Nisi, S; Oberauer, L; Obolensky, M; Ortica, F; Otis, K; Pallavicini, M; Papp, L; Perasso, L; Perasso, S; Pocar, A; Ranucci, G; Razeto, A; Re, A; Romani, A; Rossi, N; Sabelnikov, A; Saldanha, R; Salvo, C; Schönert, S; Simgen, H; Skorokhvatov, M; Smirnov, O; Sotnikov, A; Sukhotin, S; Suvorov, Y; Tartaglia, R; Testera, G; Vignaud, D; Vogelaar, R B; von Feilitzsch, F; Winter, J; Wojcik, M; Wright, A; Wurm, M; Xhixha, G; Xu, J; Zaimidoroga, O; Zavatarelli, S; Zuzel, G

    2014-12-01

    The decays of (214)Po into (210)Pb and of (212)Po into (208)Pb tagged by the previous decays from (214)Bi and (212)Bi have been studied inserting quartz vials inside the Counting Test Facility (CTF) at the underground laboratory in Gran Sasso (LNGS). We find that the mean lifetime of (214)Po is (236.00 ± 0.42(stat) ± 0.15(syst)) μs and that of (212)Po is (425.1 ± 0.9(stat) ± 1.2(syst)) ns. Our results are compatible with previous measurements, have a much better signal to background ratio, and reduce the overall uncertainties. PMID:24725806

  10. 46 CFR 154.405 - Design vapor pressure (Po) of a cargo tank.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Design vapor pressure (Po) of a cargo tank. 154.405... Equipment Cargo Containment Systems § 154.405 Design vapor pressure (Po) of a cargo tank. (a) The design vapor pressure (Po) of a cargo tank must be equal to or greater than the MARVS. (b) The Po of a...

  11. 46 CFR 154.405 - Design vapor pressure (Po) of a cargo tank.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Design vapor pressure (Po) of a cargo tank. 154.405... Equipment Cargo Containment Systems § 154.405 Design vapor pressure (Po) of a cargo tank. (a) The design vapor pressure (Po) of a cargo tank must be equal to or greater than the MARVS. (b) The Po of a...

  12. 46 CFR 154.405 - Design vapor pressure (Po) of a cargo tank.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Design vapor pressure (Po) of a cargo tank. 154.405... Equipment Cargo Containment Systems § 154.405 Design vapor pressure (Po) of a cargo tank. (a) The design vapor pressure (Po) of a cargo tank must be equal to or greater than the MARVS. (b) The Po of a...

  13. 46 CFR 154.405 - Design vapor pressure (Po) of a cargo tank.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Design vapor pressure (Po) of a cargo tank. 154.405... Equipment Cargo Containment Systems § 154.405 Design vapor pressure (Po) of a cargo tank. (a) The design vapor pressure (Po) of a cargo tank must be equal to or greater than the MARVS. (b) The Po of a...

  14. 46 CFR 154.405 - Design vapor pressure (Po) of a cargo tank.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Design vapor pressure (Po) of a cargo tank. 154.405... Equipment Cargo Containment Systems § 154.405 Design vapor pressure (Po) of a cargo tank. (a) The design vapor pressure (Po) of a cargo tank must be equal to or greater than the MARVS. (b) The Po of a...

  15. 49 CFR 604.34 - Chief Counsel decisions and appointment of a PO.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Chief Counsel decisions and appointment of a PO... Presiding Official (PO) § 604.34 Chief Counsel decisions and appointment of a PO. (a) After receiving a... decision based on the pleadings filed to date; (2) Appoint a PO to review the matter; or (3) Dismiss...

  16. 49 CFR 604.34 - Chief Counsel decisions and appointment of a PO.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 7 2012-10-01 2012-10-01 false Chief Counsel decisions and appointment of a PO... Presiding Official (PO) § 604.34 Chief Counsel decisions and appointment of a PO. (a) After receiving a... decision based on the pleadings filed to date; (2) Appoint a PO to review the matter; or (3) Dismiss...

  17. 49 CFR 604.34 - Chief Counsel decisions and appointment of a PO.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 7 2014-10-01 2014-10-01 false Chief Counsel decisions and appointment of a PO... Presiding Official (PO) § 604.34 Chief Counsel decisions and appointment of a PO. (a) After receiving a... decision based on the pleadings filed to date; (2) Appoint a PO to review the matter; or (3) Dismiss...

  18. 49 CFR 604.34 - Chief Counsel decisions and appointment of a PO.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 7 2013-10-01 2013-10-01 false Chief Counsel decisions and appointment of a PO... Presiding Official (PO) § 604.34 Chief Counsel decisions and appointment of a PO. (a) After receiving a... decision based on the pleadings filed to date; (2) Appoint a PO to review the matter; or (3) Dismiss...

  19. 49 CFR 604.34 - Chief Counsel decisions and appointment of a PO.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 7 2011-10-01 2011-10-01 false Chief Counsel decisions and appointment of a PO... Presiding Official (PO) § 604.34 Chief Counsel decisions and appointment of a PO. (a) After receiving a... decision based on the pleadings filed to date; (2) Appoint a PO to review the matter; or (3) Dismiss...

  20. Comparison of electrochemical performances of olivine NaFePO4 in sodium-ion batteries and olivine LiFePO4 in lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Zhu, Yujie; Xu, Yunhua; Liu, Yihang; Luo, Chao; Wang, Chunsheng

    2012-12-01

    Carbon-coated olivine NaFePO4 (C-NaFePO4) spherical particles with a uniform diameter of ~80 nm are obtained by chemical delithiation and subsequent electrochemical sodiation of carbon-coated olivine LiFePO4 (C-LiFePO4), which is synthesized by a solvothermal method. The C-NaFePO4 electrodes are identical (particle size, particle size distribution, surface coating, and active material loading, etc.) to C-LiFePO4 except that Li ions in C-LiFePO4 are replaced by Na ions, making them ideal for comparison of thermodynamics and kinetics between C-NaFePO4 cathode in sodium-ion (Na-ion) batteries and C-LiFePO4 in lithium-ion (Li-ion) batteries. In this paper, the equilibrium potentials, reaction resistances, and diffusion coefficient of Na in C-NaFePO4 are systematically investigated by using the galvanostatic intermittent titration technique (GITT), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), and compared to those of the well-known LiFePO4 cathodes in Li-ion batteries. Due to the lower diffusion coefficient of Na-ion and higher contact and charge transfer resistances in NaFePO4 cathodes, the rate performance of C-NaFePO4 in Na-ion batteries is much worse than that of C-LiFePO4 in Li-ion batteries. However, the cycling stability of C-NaFePO4 is almost comparable to C-LiFePO4 by retaining 90% of its capacity even after 100 charge-discharge cycles at a charge-discharge rate of 0.1 C.Carbon-coated olivine NaFePO4 (C-NaFePO4) spherical particles with a uniform diameter of ~80 nm are obtained by chemical delithiation and subsequent electrochemical sodiation of carbon-coated olivine LiFePO4 (C-LiFePO4), which is synthesized by a solvothermal method. The C-NaFePO4 electrodes are identical (particle size, particle size distribution, surface coating, and active material loading, etc.) to C-LiFePO4 except that Li ions in C-LiFePO4 are replaced by Na ions, making them ideal for comparison of thermodynamics and kinetics between C-NaFePO4 cathode in

  1. RAPID DETERMINATION OF {sup 210} PO IN WATER SAMPLES

    SciTech Connect

    Maxwell, S.

    2013-05-22

    A new rapid method for the determination of {sup 210}Po in water samples has been developed at the Savannah River National Laboratory (SRNL) that can be used for emergency response or routine water analyses. If a radiological dispersive device (RDD) event or a radiological attack associated with drinking water supplies occurs, there will be an urgent need for rapid analyses of water samples, including drinking water, ground water and other water effluents. Current analytical methods for the assay of {sup 210}Po in water samples have typically involved spontaneous auto-deposition of {sup 210}Po onto silver or other metal disks followed by counting by alpha spectrometry. The auto-deposition times range from 90 minutes to 24 hours or more, at times with yields that may be less than desirable. If sample interferences are present, decreased yields and degraded alpha spectrums can occur due to unpredictable thickening in the deposited layer. Separation methods have focused on the use of Sr Resin, often in combination with 210Pb analysis. A new rapid method for {sup 210}Po in water samples has been developed at the Savannah River National Laboratory (SRNL) that utilizes a rapid calcium phosphate co-precipitation method, separation using DGA Resin (N,N,N,N-tetraoctyldiglycolamide extractant-coated resin, Eichrom Technologies or Triskem-International), followed by rapid microprecipitation of {sup 210}Po using bismuth phosphate for counting by alpha spectrometry. This new method can be performed quickly with excellent removal of interferences, high chemical yields and very good alpha peak resolution, eliminating any potential problems with the alpha source preparation for emergency or routine samples. A rapid sequential separation method to separate {sup 210} Po and actinide isotopes was also developed. This new approach, rapid separation with DGA Resin plus microprecipitation for alpha source preparation, is a significant advance in radiochemistry for the rapid

  2. PoSSUM: Polar Suborbital Science in the Upper Mesosphere

    NASA Astrophysics Data System (ADS)

    Reimuller, J. D.; Fritts, D. C.; Thomas, G. E.; Taylor, M. J.; Mitchell, S.; Lehmacher, G. A.; Watchorn, S. R.; Baumgarten, G.; Plane, J. M.

    2013-12-01

    Project PoSSUM (www.projectpossum.org) is a suborbital research project leveraging imaging and remote sensing techniques from Reusable Suborbital Launch Vehicles (rSLVs) to gather critical climate data through use of the PoSSUM Observatory and the PoSSUM Aeronomy Laboratory. An acronym for Polar Suborbital Science in the Upper Mesosphere, PoSSUM grew from the opportunity created by the Noctilucent Cloud Imagery and Tomography Experiment, selected by the NASA Flight Opportunities Program as Experiment 46-S in March 2012. This experiment will employ an rSLV (e.g. the XCOR Lynx Mark II) launched from a high-latitude spaceport (e.g. Eielson AFB, Alaska or Kiruna, Sweden) during a week-long deployment scheduled for July 2015 to address critical questions concerning noctilucent clouds (NLCs) through flights that transition the cloud layer where the clouds will be under direct illumination from the sun. The 2015 Project PoSSUM NLC campaign will use the unique capability of rSLVs to address key under-answered questions pertaining to NLCs. Specifically, PoSSUM will answer: 1) What are the small-scale dynamics of NLCs and what does this tell us about the energy and momentum deposition from the lower atmosphere? 2) What is the seasonal variability of NLCs, mesospheric dynamics, and temperatures? 3) Are structures observed in the OH layer coupled with NLC structures? 4) How do NLCs nucleate? and 5) What is the geometry of NLC particles and how do they stratify? Instrumentation will include video and still-frame visible cameras (PoSSUMCam), infrared cameras, a mesospheric temperatures experiment, a depolarization LiDAR, a mesospheric density and temperatures experiment (MCAT), a mesospheric winds experiment, and a meteoric smoke detector (MASS). The instrument suite used on PoSSUM will mature through subsequent campaigns to develop an integrated, modular laboratory (the ';PoSSUM Observatory') that will provide repeatable, low cost, in-situ NLC and aeronomy observations as well

  3. Introducing the Adler E/PO Partnership Template

    NASA Astrophysics Data System (ADS)

    Hammergren, M.

    2003-12-01

    Education is now a core mission of NASA. Other funding agencies are increasingly insistent that researchers become scientist-educators. This trend is reflected in the growing integration of education and public outreach (E/PO) efforts within research proposals of all scales. Given little guidance apart from a budget cap, scientists can often be confused regarding the appropriate audience, content, and scale of E/PO proposals. Opened to the public in 1930 as the first planetarium in the western hemisphere, the Adler Planetarium & Astronomy Museum has inspired generations of explorers through innovative astronomy education. The Adler has a long history of successfully working with outside partners on E/PO programs, and we are enthusiastic about developing new partnerships to improve astronomy education. As part of these efforts, we will present a comprehensive source of information on the Adler's unique strengths and resources, along with a template for proposing E/PO partnerships with the Adler. The two-way exchange of information will aid in setting realistic and realizable goals for the E/PO effort, and help both parties decide whether the partnership is something they want to pursue. This service will be available online through a link on the Adler website at www.adlerplanetarium.org.

  4. Baseline concentration of Polonium-210 ((210)Po) in tuna fish.

    PubMed

    Khan, M Feroz; Wesley, S Godwin

    2016-06-15

    Several species of tuna fish were analyzed for (210)Po content in their edible muscle tissues. This study was carried out as a part of baseline data generation around a large nuclear power plant situated at Kudankulam, southeast coast of India. The concentration of (210)Po in the muscle tissue ranged from 40.9±5.2 to 92.5±7.9Bq/kg of fresh fish, and the highest activity was recorded for the tuna Euthynnus affinis and the lowest for Auxis thazard. The committed effective dose to the local residents was calculated to be 62.7-141.8μSvyear(-1).

  5. Optimization of Carbon Coatings on LiFePO4

    SciTech Connect

    Doeff, Marca M.; Wilcox, James D.; Kostecki, Robert; Lau, Grace

    2005-07-14

    The electrochemical performance of LiFePO{sub 4} in lithium cells is strongly dependent on the structure (disordered/graphene or D/G ratio) of the in situ carbon produced during synthesis from carbon-containing precursors. Addition of pyromellitic acid (PA) prior to final calcination results in lower D/G ratios, yielding a higher-rate material. Further, improvements in electrochemical performance are realized when graphitization catalysts such as ferrocene are also added during LiFePO{sub 4} preparation, although overall carbon content is still less than 2 wt.%.

  6. Evaluation of new primers for CSF1PO.

    PubMed

    Yoshida, K; Sekiguchi, K; Kasai, K; Sato, H; Seta, S; Sensabaugh, G F

    1997-01-01

    We describe new primers for the detection of the STR polymorphism at the CSF1PO locus. These primers have been designed to produce shorter amplicons (150-182 bp) than the primers in standard use (295-327 bp). The reliability of the new primers for CSF1PO typing has been demonstrated by testing on known samples and by sequence analysis. These primers are superior to the original primers with regard to electrophoretic resolution and utility for typing of severely degraded DNA.

  7. Baseline concentration of Polonium-210 ((210)Po) in tuna fish.

    PubMed

    Khan, M Feroz; Wesley, S Godwin

    2016-06-15

    Several species of tuna fish were analyzed for (210)Po content in their edible muscle tissues. This study was carried out as a part of baseline data generation around a large nuclear power plant situated at Kudankulam, southeast coast of India. The concentration of (210)Po in the muscle tissue ranged from 40.9±5.2 to 92.5±7.9Bq/kg of fresh fish, and the highest activity was recorded for the tuna Euthynnus affinis and the lowest for Auxis thazard. The committed effective dose to the local residents was calculated to be 62.7-141.8μSvyear(-1). PMID:27045047

  8. Structural and Electrochemical Characterization of Pure LiFePO 4 and Nanocomposite C- LiFePO 4 Cathodes for Lithium Ion Rechargeable Batteries

    DOE PAGES

    Kumar, Arun; Thomas, R.; Karan, N. K.; Saavedra-Arias, J. J.; Singh, M. K.; Majumder, S. B.; Tomar, M. S.; Katiyar, R. S.

    2009-01-01

    Pure limore » thium iron phosphate ( LiFePO 4 ) and carbon-coated LiFePO 4 (C- LiFePO 4 ) cathode materials were synthesized for Li-ion batteries. Structural and electrochemical properties of these materials were compared. X-ray diffraction revealed orthorhombic olivine structure. Micro-Raman scattering analysis indicates amorphous carbon, and TEM micrographs show carbon coating on LiFePO 4 particles. Ex situ Raman spectrum of C- LiFePO 4 at various stages of charging and discharging showed reversibility upon electrochemical cycling. The cyclic voltammograms of LiFePO 4 and C- LiFePO 4 showed only a pair of peaks corresponding to the anodic and cathodic reactions. The first discharge capacities were 63, 43, and 13 mAh/g for C/5, C/3, and C/2, respectively for LiFePO 4 where as in case of C- LiFePO 4 that were 163, 144, 118, and 70 mAh/g for C/5, C/3, C/2, and 1C, respectively. The capacity retention of pure LiFePO 4 was 69% after 25 cycles where as that of C- LiFePO 4 was around 97% after 50 cycles. These results indicate that the capacity and the rate capability improved significantly upon carbon coating.« less

  9. Neutron diffraction studies of the Na-ion battery electrode materials NaCoCr2(PO4)3, NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3

    NASA Astrophysics Data System (ADS)

    Yahia, H. Ben; Essehli, R.; Avdeev, M.; Park, J.-B.; Sun, Y.-K.; Al-Maadeed, M. A.; Belharouak, I.

    2016-06-01

    The new compounds NaCoCr2(PO4)3, NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3 were synthesized by sol-gel method and their crystal structures were determined by using neutron powder diffraction data. These compounds were characterized by galvanometric cycling and cyclic voltammetry. NaCoCr2(PO4)3, NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3 crystallize with a stuffed α-CrPO4-type structure. The structure consists of a 3D-framework made of octahedra and tetrahedra that are sharing corners and/or edges generating channels along [100] and [010], in which the sodium atoms are located. Of significance, in the structures of NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3 a statistical disorder Ni2+/Cr3+ was observed on both the 8g and 4a atomic positions, whereas in NaCoCr2(PO4)3 the statistical disorder Co2+/Cr3+ was only observed on the 8g atomic position. When tested as negative electrode materials, NaCoCr2(PO4)3, NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3 delivered specific capacities of 352, 385, and 368 mA h g-1, respectively, which attests to the electrochemical activity of sodium in these compounds.

  10. Dominant-negative effect on adhesion by myelin Po protein truncated in its cytoplasmic domain

    PubMed Central

    1996-01-01

    The myelin Po protein is believed to hold myelin together via interactions of both its extracellular and cytoplasmic domains. We have already shown that the extracellular domains of Po can interact in a homophilic manner (Filbin, M.T., F.S. Walsh, B.D. Trapp, J.A. Pizzey, and G.I. Tennekoon. 1990. Nature (Lond.). 344:871-872). In addition, we have shown that for this homophilic adhesion to take place, the cytoplasmic domain of Po must be intact and most likely interacting with the cytoskeleton; Po proteins truncated in their cytoplasmic domains are not adhesive (Wong, M.H., and M.T. Filbin, 1994. J. Cell Biol. 126:1089-1097). To determine if the presence of these truncated forms of Po could have an effect on the functioning of the full-length Po, we coexpressed both molecules in CHO cells. The adhesiveness of CHO cells expressing both full-length Po and truncated Po was then compared to cells expressing only full-length Po. In these coexpressors, both the full-length and the truncated Po proteins were glycosylated. They reached the surface of the cell in approximately equal amounts as shown by an ELISA and surface labeling, followed by immunoprecipitation. Furthermore, the amount of full-length Po at the cell surface was equivalent to other cell lines expressing only full-length Po that we had already shown to be adhesive. Therefore, there should be sufficient levels of full-length Po at the surface of these coexpressors to measure adhesion of Po. However, as assessed by an aggregation assay, the coexpressors were not adhesive. By 60 min they had not formed large aggregates and were indistinguishable from the control transfected cells not expressing Po. In contrast, in the same time, the cells expressing only the full-length Po had formed large aggregates. This indicates that the truncated forms of Po have a dominant-negative effect on the adhesiveness of the full-length Po. Furthermore, from cross-linking studies, full-length Po, when expressed alone but not when

  11. [Establishment and activity of PoKuNyoKwan].

    PubMed

    Lee, Bang Weon

    2008-06-01

    PoKuNyoKwan was established in 1887 by Meta Howard, a female doctor who was dispatched from Woman's Foreign Missionary Society, an evangelical branch affiliated with U.S. North Methodist Church. PoKuNyoKwan was equipped with dispensaries, waiting rooms, pharmacies, warehouses, operating rooms, and wards for about 30 patients. It used a traditional Korean house, which was renovated for its medical purpose, in Ewha Haktang. Residing in Chung Dong, the medical institution had taken care of women's mental and physical health for about 25 years, until it was merged with East Gate Lillian Harris Memorial Hospital in 1912, and then its dispensary function was abolished in 1913. Medical missionaries (Meta Howard, Rosetta Sherwood, Mary M. Cutler, Emma Ernsberger, Esther K. Pak, Amanda F. Hillman) and nurse missionaries (Ella Lewis, Margaret J. Edmunds, Alta I. Morrison, Naomi A. Anderson), who were professionally trained in the United States, and their helpers, who were trained by those missionaries, managed PoKuNyoKwan. Nurses who were educated in Nurses' Training School, which was also established by PoKuNyoKwan, helped to run the institution as well. At the beginning, they usually had worked as a team of one medical missionary and three helpers. Since its establishment in 1903, however, the helpers began to enter the Nurses' Training School to become professional nurses, and the helpers eventually faded out because of the proliferation of those nurses. PoKuNyoKwan did not only offer medical services but also executed educational and evangelical activities. Medical missionaries struggled to overcome Koreans' ignorance and prejudice against westerners and western medical services, while they took care of their patients at office, for calls, and in hospital dispensaries. Enlightening the public by criticizing Korean traditional medical treatments including fork remedies, acupuncture, and superstitions, they helped modernization of medical systems in Korea. In the area of

  12. Size-dependent magnetic ordering and spin dynamics in DyPO4 and GdPO4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Evangelisti, Marco; Sorop, Tibi G.; Bakharev, Oleg N.; Visser, Dirk; Hillier, Adrian D.; Alonso, Juan J.; Haase, Markus; Boatner, Lynn A.; Jos de Jongh, L.

    2011-09-01

    Low-temperature magnetic susceptibility and heat-capacity measurements on nanoparticles (d≈ 2.6 nm) of the antiferromagnetic compounds DyPO4 (TN=3.4 K) and GdPO4 (TN=0.77 K) provide clear demonstrations of finite-size effects, which limit the divergence of the magnetic correlation lengths, thereby suppressing the bulk long-range magnetic ordering transitions. Instead, the incomplete antiferromagnetic order inside the particles leads to the formation of net magnetic moments on the particles. For the nanoparticles of Ising-type DyPO4 superparamagnetic blocking is found in the ac susceptibility at ≃1 K, those of the XY-type GdPO4 analog show a dipolar spin-glass transition at ≃0.2 K. Monte Carlo simulations for the magnetic heat capacities of both bulk and nanoparticle samples are in agreement with the experimental data. Strong size effects are also apparent in the Dy3+ and Gd3+ spin dynamics, which were studied by zero-field muon spin rotation (μSR) and high-field 31P-nuclear magnetic resonance (31P-NMR) nuclear relaxation measurements. The freezing transitions observed in the ac susceptibility of the nanoparticles also appear as peaks in the temperature dependence of the zero-field μSR rates, but at slightly higher temperatures, as to be expected from the higher frequency of the muon probe. For both bulk and nanoparticles of GdPO4, the muon and 31P-NMR rates are for T⩾5 K dominated by exchange-narrowed hyperfine broadening arising from the electron spin-spin interactions inside the particles. The dipolar hyperfine interactions acting on the muons and the 31P are, however, much reduced in the nanoparticles. For the DyPO4 analogs the high-temperature rates appear to be fully determined by electron spin-lattice relaxation processes.

  13. Size-dependent magnetic ordering and spin-dynamics in DyPO4 and GdPO4 nanoparticles

    SciTech Connect

    Evangelisti, Marco; Sorop, Tibi G; Bakharev, Oleg N; Visser, Dirk; Hillier, Adrian D.; Alonso, Juan; Haase, Markus; Boatner, Lynn A; De Jongh, L. Jos

    2011-01-01

    Low-temperature magnetic susceptibility and heat capacity measurements on nanoparticles (d 2.6 nm) of the antiferromagnetic compounds DyPO4 (TN = 3:4 K) and GdPO4 (TN = 0:77 K) provide clear demonstrations of finite-size effects, which limit the divergence of the magnetic correlation lengths, thereby suppressing the bulk long-range magnetic ordering transitions. Instead, the incomplete antiferromagnetic order inside the particles leads to the formation of net magnetic moments on the particles. For the nanoparticles of Ising-type DyPO4 superparamagnetic blocking is found in the ac-susceptibility at 1 K, those of the XY-type GdPO4 analogue show a dipolar spin-glass transition at 0:2 K. Monte Carlo simulations for the magnetic heat capacities of both bulk and nanoparticle samples are in agreement with the experimental data. Strong size effects are also apparent in the Dy3+ and Gd3+ spin-dynamics, which were studied by zero-field SR relaxation and high-field 31P-NMR nuclear relaxation measurements. The freezing transitions observed in the ac-susceptibility of the nanoparticles also appear as peaks in the temperature dependence of the zero-field SR rates, but at slightly higher temperatures - as to be expected from the higher frequency of the muon probe. For both bulk and nanoparticles of GdPO4, the muon and 31P-NMR rates are for T 5 K dominated by exchange-narrowed hyperfine broadening arising from the electron spin-spin interactions inside the particles. The dipolar hyperfine interactions acting on the muons and the 31P are, however, much reduced in the nanoparticles. For the DyPO4 analogues the high-temperature rates appear to be fully determined by electron spin-lattice relaxation processes.

  14. Polonium 210Po in cigarettes produced in Poland.

    PubMed

    Skwarzec, B; Strumińska, D I; Borylo, A; Ulatowski, J

    2001-01-01

    This paper discusses the results of 210Po determinations in the fourteen most frequently smoked brands of cigarettes, which constitute over 80% of total cigarette consumption in Poland. The 210Po activity in the cigarette samples analysed (tobacco, ash, filter before and after smoking) were measured using alpha spectrometry (Canberra-Packard). The data indicates that there is considerable variation in the polonium content of these brands. The highest 210Po content per sample was found in the cheap "Popularne" brand (24.12 mBq), the lowest in "Caro" (4.23 mBq). There was also a large difference between the polonium remaining in the ash in comparison with its total content in the tobacco in all the brands (from 4.3% for "Golden American" to 71.0% for "Sobieski King-Size"). The analysis has demonstrated that filters absorbed only a small amount of the polonium contained in the tobacco. "Caro" cigarettes have the most efficient filter, retaining 25.1% of the polonium contained in the tobacco, but most filters absorbed only 0.1-7.2% of polonium. The daily inhalation of 210Po by Polish smokers who get through one pack per day ranges from 20 to 215 mBq, but people smoking two or more packs of "Popularne" brand will inhale over 430 mBq of polonium per day.

  15. Bioaccumulation of polonium 210Po in marine birds.

    PubMed

    Skwarzec, B; Fabisiak, J

    2007-01-01

    The aim of this work was to determine the 210Po content in marine birds which permanently or temporally live in the Polish part of the Baltic Sea. We chose 11 species of sea birds: three species permanently residing at southern Baltic Sea, four species of wintering birds and three species of migrating birds. The results show that the polonium is non-uniformly distributed in the marine birds. The highest activities of 210Po were observed in feathers, muscles and liver and the lowest in skin and skeleton. Species of birds that eat crustaceans, molluscs, fish and plants (long-tailed duck Clangula hyemalis, white-winged scoter Melanitta fusca) accumulated more polonium than species that eat mainly fish (great cormorant Phalacrocorax carbo, common guillemot Uria aalge) or plants (tufted duck Aythya fuligula). Moreover, about 63% of the 210Po that was located in feathers of razorbil (Alca torda) and long-tailed duck (C. hyemalis) was apparently adsorbed, suggesting an external source such as the air. It means that the adsorption of 210Po on the feather surface may be an important transfer from air to water.

  16. America's Earliest Revolutionary Voice: Po-Pay--Not Patrick Henry.

    ERIC Educational Resources Information Center

    Owen, Gordon R.

    A full century before Patrick Henry's persuasive battle for the rights of oppressed people, a San Juan Pueblo Indian medicine man known only as Po-Pay was the masterful communicator and agitator who orchestrated the first American revolution to drive the Spanish back into Mexico. Seeking mineral wealth, cheap labor, and the maximum number of…

  17. Recoil-deposited Po-210 in radon dwellings

    SciTech Connect

    Samuelsson, C.

    1990-12-31

    Short-lived decay products of Rn-222 plate out on all surfaces in a house containing radon gas. Following the subsequent alpha decays of the mother nuclei, the daughter products Pb-214 and Pb-210 are superficially and permanently absorbed. Due to its long half-life (22 y) the activity of absorbed Pb-210 accumulates in the surface. The activity of Pb-210, or its decay products, can thus reflect the past randon daughter and plate-out history of a house over several decades. Our results and experience from measurements of Po-210 and Rn-222 in 22 dwellings will be presented. In these studies the Po-210 surface activity of one plane glass sheet per dwelling (window panes were not used) has been determined and compared with the period of exposure times the mean radon concentration measured over a two-month period. Considering the large uncertainty in the integrated radon exposure estimate the surface {sup 210}Po correlates well (r=0.73) with the accumulated radon exposure. The {sup 210}Po activity of the glass samples has been measured non-destructively using an open-flow pulse ionization chamber and this detector has also been successfully applied in field exercises.

  18. PoGOLite measurement of Crab polarisation and future plans

    NASA Astrophysics Data System (ADS)

    Pearce, Mark

    2016-07-01

    (For the PoGOLite Collaboration) The PoGOLite Pathfinder is a balloon-borne hard X-ray polarimeter designed for the observation of bright, ~1 Crab, sources. Polarisation is determined by measuring the azimuthal Compton scattering angle of incident X-rays in an array of plastic scintillators housed in an BGO anticoincidence well. The PoGOLite Pathfinder was launched from the SSC Esrange Space Centre in July 2013 resulting in a near-circumpolar flight of two weeks duration. The linear polarisation of hard X-ray emissions from the Crab was measured in a previously unexplored energy interval, 20-120 keV. The polarimetric response was characterised prior to flight using both polarised and unpolarised calibration sources. Systematic effects were addressed through observations of a background field. An upgraded polarimeter, PoGO+, is scheduled to fly in summer 2016 from Esrange. Results from the 2013 Pathfinder flight and prospects for the 2016 flight will be discussed.

  19. The BiPo detector for ultralow radioactivity measurements

    SciTech Connect

    Bongrand, Mathieu

    2011-04-27

    The development of BiPo detectors is dedicated to the measurement of extremely high radiopurity in {sup 208}Tl and {sup 214}Bi for the SuperNEMO double beta decay source foils. A modular prototype called BiPo-1 with 0.8 m{sup 2} of sensitive surface area has been running in the Modane Underground Laboratory since February 2008. The goal of BiPo-1 is to measure the different components of the background and in particular the surface radiopurity of the plastic scintillators that make up the detector. The first phase of data collection has been dedicated to the measurement of the radiopurity in {sup 208}Tl. After more than one year of background measurement a surface activity of the scintillators of A({sup 208}Tl) = 1.5 {mu}Bq/m{sup 2} is reported here.Given this level of background, a larger BiPo3 detector having 3.25 m{sup 2} of active surface area, will able to qualify the radiopurity of the SuperNEMO selenium double beta decay foils with the required sensitivity of A({sup 208}Tl)<3-4 {mu}Bq/kg(90% C.L.) with a six month measurement. This detector is actually under construction and will be installed in the Canfranc Underground Laboratory mid 2011.

  20. Pinunuuchi Po'og'ani: Southern Ute Indian Academy.

    ERIC Educational Resources Information Center

    Oberly, Stacey Inez (Wachimamachi [Antelope Woman])

    2002-01-01

    Describes the Pinunuuchi Po'og'ani, the Southern Ute Indian Academy, providing Montessori education for Southern Ute tribal members ages 6 weeks through 10 years and reviving the use of the Southern Ute language and culture among young students and their families. Describes how the program supports families, students, and staff, and incorporates…

  1. Measurement of airborne {sup 218}Po - A Bayesian approach

    SciTech Connect

    Groer, P.G.; Lo, Y.

    1996-12-01

    The standard mathematical treatment of the buildup and decay of airborne radionuclides on a filter paper uses the solutions of the so-called bateman equations adapted to the sampling process. The equations can be interpreted as differential equations for the expectation of an underlying stochastic process, which describes the random fluctuations in the accumulation and decay of the sampled radioactive atoms. The process for the buildup and decay of airborne {sup 218}Po can be characterized as an {open_quotes}immigration-death process{close_quotes} in the widely adopted, biologically based jargon. The probability distribution for the number of {sup 218}Po atoms, accumulated after sampling time t, is Poisson. We show that the distribution of the number of counts, registered by a detector with efficiency {epsilon} during a counting period T after the end of sampling, it also Poisson, with mean dependent on {epsilon},t,T, the flowrate and N{sub o}, the number of airborne {sup 218}Po atoms per unit volume. This Poisson distribution was used to construct the likelihood given the observed number of counts. After inversion with Bayes` Theorem we obtained the posterior density for N{sub o}. This density characterizes the remaining uncertainty about the measured under of {sup 218}Po atoms per unit volume of air. 6 refs., 3 figs., 1 tab.

  2. Structure for Storing Properties of Particles (PoP)

    SciTech Connect

    Patel, N. R.; Mattoon, C. M.; Beck, B. R.; Summers, N. C.; Brown, D. A.

    2014-06-01

    Some evaluated nuclear databases are critical for applications such as nuclear energy, nuclear medicine, homeland security, and stockpile stewardship. Particle masses, nuclear excitation levels, and other “Properties of Particles” are essential for making evaluated nuclear databases. Currently, these properties are obtained from various databases that are stored in outdated formats. Moreover, the “Properties of Particles” (PoP) structure is being designed that will allow storing all information for one or more particles in a single place, so that each evaluation, simulation, model calculation, etc. can link to the same data. Information provided in PoP will include properties of nuclei, gammas and electrons (along with other particles such as pions, as evaluations extend to higher energies). Presently, PoP includes masses from the Atomic Mass Evaluation version 2003 (AME2003), and level schemes and gamma decays from the Reference Input Parameter Library (RIPL-3). The data are stored in a hierarchical structure. An example of how PoP stores nuclear masses and energy levels will be presented here.

  3. Design and network applications of PoE

    NASA Astrophysics Data System (ADS)

    Feng, Xiancheng; Yun, Xiang; Chen, Ying

    2008-12-01

    With the rapid development of digital networks, many of the appliances in life are widely used, particularly in wireless LAN and IP telephony. Ethernet-based data terminals have been widely used in many areas, although the device's power consumption is low, but in general stability and reliability of the power is of very high requirements. In this paper, PoE technology (a solution focused on long-distance power supply system) is focused on the PoE power supply equipment, power-operation process, the system configuration management, automatic detection, and other major technology. Also, at the same time it introduces the use of PoE technology for wireless access points designed to supply power as a kind of typical application in the local network, the programme through the network to provide power system solutions, and expand the use of PoE equipment and make full use of the existing network resources, providing users with convenient and stable service.

  4. Structure for Storing Properties of Particles (PoP)

    SciTech Connect

    Patel, N.R.; Mattoon, C.M.; Beck, B.R.; Summers, N.C.; Brown, D.A.

    2014-06-15

    Evaluated nuclear databases are critical for applications such as nuclear energy, nuclear medicine, homeland security, and stockpile stewardship. Particle masses, nuclear excitation levels, and other “Properties of Particles” are essential for making evaluated nuclear databases. Currently, these properties are obtained from various databases that are stored in outdated formats. A “Properties of Particles” (PoP) structure is being designed that will allow storing all information for one or more particles in a single place, so that each evaluation, simulation, model calculation, etc. can link to the same data. Information provided in PoP will include properties of nuclei, gammas and electrons (along with other particles such as pions, as evaluations extend to higher energies). Presently, PoP includes masses from the Atomic Mass Evaluation version 2003 (AME2003), and level schemes and gamma decays from the Reference Input Parameter Library (RIPL-3). The data are stored in a hierarchical structure. An example of how PoP stores nuclear masses and energy levels will be presented here.

  5. Development of a Portable Motor Learning Laboratory (PoMLab).

    PubMed

    Takiyama, Ken; Shinya, Masahiro

    2016-01-01

    Most motor learning experiments have been conducted in a laboratory setting. In this type of setting, a huge and expensive manipulandum is frequently used, requiring a large budget and wide open space. Subjects also need to travel to the laboratory, which is a burden for them. This burden is particularly severe for patients with neurological disorders. Here, we describe the development of a novel application based on Unity3D and smart devices, e.g., smartphones or tablet devices, that can be used to conduct motor learning experiments at any time and in any place, without requiring a large budget and wide open space and without the burden of travel on subjects. We refer to our application as POrtable Motor learning LABoratory, or PoMLab. PoMLab is a multiplatform application that is available and sharable for free. We investigated whether PoMLab could be an alternative to the laboratory setting using a visuomotor rotation paradigm that causes sensory prediction error, enabling the investigation of how subjects minimize the error. In the first experiment, subjects could adapt to a constant visuomotor rotation that was abruptly applied at a specific trial. The learning curve for the first experiment could be modeled well using a state space model, a mathematical model that describes the motor leaning process. In the second experiment, subjects could adapt to a visuomotor rotation that gradually increased each trial. The subjects adapted to the gradually increasing visuomotor rotation without being aware of the visuomotor rotation. These experimental results have been reported for conventional experiments conducted in a laboratory setting, and our PoMLab application could reproduce these results. PoMLab can thus be considered an alternative to the laboratory setting. We also conducted follow-up experiments in university physical education classes. A state space model that was fit to the data obtained in the laboratory experiments could predict the learning curves

  6. Development of a Portable Motor Learning Laboratory (PoMLab)

    PubMed Central

    Shinya, Masahiro

    2016-01-01

    Most motor learning experiments have been conducted in a laboratory setting. In this type of setting, a huge and expensive manipulandum is frequently used, requiring a large budget and wide open space. Subjects also need to travel to the laboratory, which is a burden for them. This burden is particularly severe for patients with neurological disorders. Here, we describe the development of a novel application based on Unity3D and smart devices, e.g., smartphones or tablet devices, that can be used to conduct motor learning experiments at any time and in any place, without requiring a large budget and wide open space and without the burden of travel on subjects. We refer to our application as POrtable Motor learning LABoratory, or PoMLab. PoMLab is a multiplatform application that is available and sharable for free. We investigated whether PoMLab could be an alternative to the laboratory setting using a visuomotor rotation paradigm that causes sensory prediction error, enabling the investigation of how subjects minimize the error. In the first experiment, subjects could adapt to a constant visuomotor rotation that was abruptly applied at a specific trial. The learning curve for the first experiment could be modeled well using a state space model, a mathematical model that describes the motor leaning process. In the second experiment, subjects could adapt to a visuomotor rotation that gradually increased each trial. The subjects adapted to the gradually increasing visuomotor rotation without being aware of the visuomotor rotation. These experimental results have been reported for conventional experiments conducted in a laboratory setting, and our PoMLab application could reproduce these results. PoMLab can thus be considered an alternative to the laboratory setting. We also conducted follow-up experiments in university physical education classes. A state space model that was fit to the data obtained in the laboratory experiments could predict the learning curves

  7. Development of a Portable Motor Learning Laboratory (PoMLab).

    PubMed

    Takiyama, Ken; Shinya, Masahiro

    2016-01-01

    Most motor learning experiments have been conducted in a laboratory setting. In this type of setting, a huge and expensive manipulandum is frequently used, requiring a large budget and wide open space. Subjects also need to travel to the laboratory, which is a burden for them. This burden is particularly severe for patients with neurological disorders. Here, we describe the development of a novel application based on Unity3D and smart devices, e.g., smartphones or tablet devices, that can be used to conduct motor learning experiments at any time and in any place, without requiring a large budget and wide open space and without the burden of travel on subjects. We refer to our application as POrtable Motor learning LABoratory, or PoMLab. PoMLab is a multiplatform application that is available and sharable for free. We investigated whether PoMLab could be an alternative to the laboratory setting using a visuomotor rotation paradigm that causes sensory prediction error, enabling the investigation of how subjects minimize the error. In the first experiment, subjects could adapt to a constant visuomotor rotation that was abruptly applied at a specific trial. The learning curve for the first experiment could be modeled well using a state space model, a mathematical model that describes the motor leaning process. In the second experiment, subjects could adapt to a visuomotor rotation that gradually increased each trial. The subjects adapted to the gradually increasing visuomotor rotation without being aware of the visuomotor rotation. These experimental results have been reported for conventional experiments conducted in a laboratory setting, and our PoMLab application could reproduce these results. PoMLab can thus be considered an alternative to the laboratory setting. We also conducted follow-up experiments in university physical education classes. A state space model that was fit to the data obtained in the laboratory experiments could predict the learning curves

  8. A synthesis of LiFePO{sub 4} starting from FePO{sub 4} under reducing atmosphere

    SciTech Connect

    Prosini, Pier Paolo; Cento, Cinzia; Masci, Amedeo; Carewska, Maria; Gislon, Paola

    2014-06-19

    A fast and easy way to produce LiFePO{sub 4} starting from FePO{sub 4}, used as iron and phosphorus source, is proposed. 5% hydrogen is employed as a reducing agent and various compounds containing lithium as lithiation agents. The selected lithiation agents included: LiCl, CH{sub 3}COOLi, LiOH, Li{sub 2}S, LiH, and Li{sub 2}CO{sub 3}. Solid state synthesis is used for the LiFePO{sub 4} preparation and the so obtained materials are structurally characterized by XRD. The materials are used to fabricate composite electrode and their specific capacity is evaluated by low rate galvanostatic charge/discharge cycles (C/10 rate). Among the various lithium salts, the acetate give rise to the LiFePO{sub 4} with the best electrochemical performance. The morphology of this material is further investigated by SEM microscopy and the specific capacity is evaluated as a function of the discharge rate and the cycle number.

  9. NASA's Planetary Science E/PO Forum: Reflections on Five Years of Effort to Support an E/PO Community

    NASA Astrophysics Data System (ADS)

    Shipp, S. S.; Shebby, S.; Buxner, S.; Boonstra, D.; Cobabe-Ammann, E. A.; Cobb, W. H.; Dalton, H.; Grier, J.; Klug Boonstra, S. L.; LaConte, K.; Ristvey, J.; Shupla, C. B.; Weeks, S.; Wessen, A. S.; Zimmerman-Brachman, R.

    2014-12-01

    Over the past decade, NASA's Science Mission Directorate (SMD) has funded four education and public outreach (E/PO) forums, aligned with each of its science divisions, including Astrophysics, Earth Science, Heliophysics, and Planetary Science. Together, these forums help organize individual division E/PO programs into a coordinated, effective, efficient, nationwide effort that shares the scientific discoveries of NASA across a broad array of audiences. In the past four-and-a-half years, the Planetary Science Division's Forum - in collaboration with the other three Forums - has worked to support its community of education professionals and scientists involved in E/PO to communicate, collaborate, and strengthen their efforts. The Forum's work encompasses identification of best practices based on educational research, increasing understanding of needs through audience-based working groups, the development of strategic collaborations and partnerships to increase programmatic reach, and the creation of strategic resources to support community members in their E/PO work (e.g., an online workspace for the community to communicate, collaborate, and share practices; recommendations to scientists for increasing impact in educational settings; a one-stop shop for NASA SMD classroom and informal education products, http://nasawavelength.org). Drawing on evaluation data, the presentation will explore what resources and support mechanisms are valued by the community, ways the community uses the available resources, and the outcomes of the effort to date.

  10. 76 FR 40849 - Post Office (PO) Box Fee Groups for Merged Locations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-12

    ... 111 Post Office (PO) Box Fee Groups for Merged Locations AGENCY: Postal Service. TM ACTION: Proposed... Service, Domestic Mail Manual (DMM ) 508.4 to allow Post Office TM (PO) Box fee groups to be merged due to... , with a subject line of ``PO Box Fee Group for Merged Locations.'' Faxed comments are not accepted....

  11. Thermal compensation in GaPO4 beam resonators: experimental evidence for length extensional mode.

    PubMed

    Sthal, Fabrice; Bigler, Emmanuel; Bourquin, Roger

    2007-01-01

    Temperature effects in gallium orthophosphate (GaPO4) vibrating beams are reported. In addition to the well-known, thickness-shear AT-cut, temperature-compensated cuts exist in GaPO4 for length extensional modes. Experimental evidence of a temperature-compensated cut in GaPO4 rectangular beam resonator vibrating in length extension is given. PMID:17225814

  12. Pressure-Induced Zircon-Type to Scheelite-Type Phase Transition in Orthophosphates YbPO4 and LuPO4

    SciTech Connect

    Zhang, F.; Maik, L; Ewing, R; Lian, J; Wang, Z; Hu, J; Boatner, L

    2008-01-01

    The tetragonal orthophosphates, YbPO4 and LuPO4, were studied by in situ X-ray diffraction (XRD) at pressures up to 52 and 43 GPa, respectively. A reversible phase transition from the zircon structure-type to the scheelite structure-type was found at not, vert, similar22 GPa for YbPO4 and 19 GPa for LuPO4. Coinciding with the transition from the zircon structure-type to the scheelite structure-type, there is a not, vert, similar 10% reduction in volume and a significant increase in the bulk modulus for both compounds.

  13. High pressure structural phase transitions of PbPo

    NASA Astrophysics Data System (ADS)

    Bencherif, Y.; Boukra, A.; Zaoui, A.; Ferhat, M.

    2012-09-01

    First-principles calculations have been performed to investigate the high pressure phase transitions and dynamical properties of the less known lead polonium compound. The calculated ground state parameters for the NaCl phase show good agreement with the experimental data. The obtained results show that the intermediate phase transition for this compound is the orthorhombic Pnma phase. The PbPo undergoes from the rocksalt to Pnma phase at 4.20 GPa. Further structural phase transition from intermediate to CsCl phase has been found at 8.5 GPa. In addition, phonon dispersion spectra were derived from linear-response to density functional theory. In particular, we show that the dynamical properties of PbPo exhibit some peculiar features compared to other III-V compounds. Finally, thermodynamics properties have been also addressed from quasiharmonic approximation.

  14. The BiPo detector for ultralow radioactivity measurements

    SciTech Connect

    Bongrand, M.

    2007-03-28

    The BiPo project is dedicated to the measurement of extremely low radioactivity contamination of SuperNEMO source foils (208Tl < 2 {mu}Bq/kg and 214Bi < 10 {mu}Bq/kg). The R and D phase is started : a modular BiPo prototype with its shielding test facility is under construction. The goal of this prototype is to study the background and particularly the surface contamination of scintillators. The first capsule has been installed in the Canfranc Underground Laboratory in October, 17th and is now taking data. After 10.7 days of measurements, a preliminary upper limit on the surface radiopurity of the scintillators of A(208Tl) < 60 {mu}Bq/m2 (90% C. L.) has been obtained.

  15. Graphs for Isotopes of 84-Po(Polonium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides a graphic representation of nucleon separation energies and residual interaction parameters for isotopes of the chemical element 84-Po (Polonium, atomic number Z = 84).

  16. Lattice dynamics of LuPO{sub 4}

    SciTech Connect

    Nipko, J.C. |; Loong, C.-K.; Loewenhaupt, M.; Reichardt, W.; Braden, M.; Boatner, L.A.

    1996-06-01

    Lutetium orthophosphate is an important nonmagnetic host material for rare-earth-activated luminescence applications. We have measured the LuPO{sub 4} phonon density of states and dispersion curves along the [{xi}00],[{xi}{xi}0], and [00{xi}] symmetry directions by neutron spectroscopy using polycrystalline and single-crystal samples. A quantitative analysis of the neutron results was carried out using a lattice-dynamical shell model.

  17. Stoichiometry, spin fluctuations, and superconductivity in LaNiPO

    SciTech Connect

    Klimczuk, Tomasz; Mcqueen, Tyrel M; Williams, Anthony J; Huang, Qiang; Cava, Robert J

    2009-01-01

    Superconductivity in LaNiPO is disrupted by small ({approx}5%) amounts of non-stoichiometry on the lanthanum site, even though the electronic contribution to the heat capacity increases with increasing non-stoichiometry. All samples also exhibit specific heat anomalies consistent with the presence of ferromagnetic spin fluctuations (T{sub sf}{approx} 14K). Comparison of layered nickel phosphide and nickel borocarbide superconductors reveals different structure-property correlations in the two families.

  18. Seasonal POC fluxes at BATS estimated from 210Po deficits

    NASA Astrophysics Data System (ADS)

    Stewart, Gillian M.; Bradley Moran, S.; Lomas, Michael W.

    2010-01-01

    In this study at the Bermuda Atlantic Time-series Study (BATS) site we demonstrate that the polonium-lead disequilibrium system may perform better as a tracer of organic carbon export under low-flux conditions (in this case, <2.5 mmol C m -2 d -1) than under bloom conditions in an oligotrophic setting. With very few exceptions, the POC flux predictions calculated from the water-column 210Po deficit were within a factor of 2 of the POC flux caught in surface-tethered sediment traps. However, we found higher correlation between size-fractionated particulate 210Po activity and POC concentration in November 2006 ( r=0.93) than in January ( r=0.79) and during the spring bloom in March 2007 ( r=0.80). We suggest that this is due to the ability of polonium to distinguish between bulk mass flux and organic carbon export under oligotrophic and lithogenic-driven flux regimes. Further, we found that the POC/Po ratio on particles was largely independent of size class between 10 and 100 μm ( P=0.13) during each season, supporting the notion that export in this oligotrophic system is driven by sinking aggregates of smaller cells and not by large, individual cells.

  19. A biokinetic study of 209Po in man.

    PubMed

    Henricsson, C F; Ranebo, Y; Hansson, M; Rääf, C L; Holm, E

    2012-10-15

    Five adult volunteers participated in a biokinetic study of radioactive polonium. Portions of about 10 Bq of (209)Po were orally administrated to four of the volunteers in a single ingestion. The fifth volunteer ingested a daily amount of 53 mBq of 209Po for 243 d to study the time to achieve equilibrium between intake and excretion for protracted intakes. For the subjects ingesting single intakes of (209)Po complete sampling of urine and feces was subsequently collected the first few days upon the ingestion. The samples were processed with radiochemical extraction and analyzed with alpha spectrometry. In the study, the maximum daily excretion rates in feces were 18-50% of the ingested activity, observed within 3 d after intake. Regarding the urine excretion, the daily excretion peaked, on average, at 0.15-1% of the ingested activity within two days upon intake. These results indicate an average gastro-intestinal uptake fraction of 0.46±0.08, which agrees well with earlier biokinetic studies of polonium in man.

  20. Origin of the charge gap in LaMnPO

    DOE PAGES

    McNally, D. E.; Simonson, Jack W.; Post, K. W.; Yin, Zhiping P.; Pezzoli, M.; Smith, G. J.; Leyva, V.; Marques, C.; Debeer-Schmitt, Lisa M.; Kolesnikov, Alexander I.; et al

    2014-11-18

    In this paper, we present high temperature inelastic neutron scattering and magnetic susceptibility measurements of the antiferromagnetic insulator LaMnPO that are consistent with the presence of two-dimensional magnetic correlations up to a temperature Tmax≈700K»TN=375 K, the Néel temperature. Optical transmission measurements show the T=300 K direct charge gap Δ=1 eV has decreased only marginally by 500 K and suggest it decreases by only 10% at Tmax. Density functional theory and dynamical mean-field theory calculations reproduce a direct charge gap in paramagnetic LaMnPO only when a strong Hund's coupling JH=0.9 eV is included, as well as on-site Hubbard U=8 eV. Inmore » conclusion, our results show that LaMnPO is a Mott-Hund's insulator, in which the charge gap is rather insensitive to antiferromagnetic exchange coupling.« less

  1. Can Vanadium Be Substituted into LiFePO4

    SciTech Connect

    Omenya F.; Nam K.; Chernova N.A.; Upreti S.; Zavalij P.Y.; Nam K.-W.; Yang X.-Q.; Whittingham M.S.

    2011-11-08

    Vanadium is shown to substitute for iron in the olivine LiFePO{sub 4} up to at least 10 mol %, when the synthesis is carried out at 550 C. In the solid solution LiFe{sub 1-3y/2}V{sub y}PO{sub 4}, the a and b lattice parameters and cell volume decrease with increasing vanadium content, while the c lattice parameter increases slightly. However, when the synthesis is performed at 650 C, a NASICON phase, Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}, is also formed, showing that solid solution is a function of the synthesis temperature. X-ray absorption near-edge structure indicates vanadium is in the 3+ oxidation state and in an octahedral environment. Magnetic studies reveal a shift of the antiferromagnetic ordering transition toward lower temperatures with increasing vanadium substitution, confirming solid solution formation. The addition of vanadium enhances the electrochemical performance of the materials especially at high current densities.

  2. Origin of the charge gap in LaMnPO

    SciTech Connect

    McNally, D. E.; Simonson, Jack W.; Post, K. W.; Yin, Zhiping P.; Pezzoli, M.; Smith, G. J.; Leyva, V.; Marques, C.; Debeer-Schmitt, Lisa M.; Kolesnikov, Alexander I.; Zhao, Yang; Lynn, J. W.; Basov, D. N.; Kotliar, G.; Aronson, Meigan C.

    2014-11-18

    In this paper, we present high temperature inelastic neutron scattering and magnetic susceptibility measurements of the antiferromagnetic insulator LaMnPO that are consistent with the presence of two-dimensional magnetic correlations up to a temperature Tmax≈700K»TN=375 K, the Néel temperature. Optical transmission measurements show the T=300 K direct charge gap Δ=1 eV has decreased only marginally by 500 K and suggest it decreases by only 10% at Tmax. Density functional theory and dynamical mean-field theory calculations reproduce a direct charge gap in paramagnetic LaMnPO only when a strong Hund's coupling JH=0.9 eV is included, as well as on-site Hubbard U=8 eV. In conclusion, our results show that LaMnPO is a Mott-Hund's insulator, in which the charge gap is rather insensitive to antiferromagnetic exchange coupling.

  3. Visible light assisted degradation of organic dye using Ag3PO4

    NASA Astrophysics Data System (ADS)

    Dhanabal, R.; Velmathi, S.; Bose, A. Chandra

    2015-06-01

    The study of visible light photodegradation of organic dye Methylene Blue (MB) have been investigated using silver phosphate (Ag3PO4) as a photocatalyst which is good efficient material for photocatalytic reaction. The simple ion-exchange method is used to prepare Ag3PO4. The structure of the material have been confirmed using X-ray diffraction which shows cubic structure of Ag3PO4. The functional group of the Ag3PO4 has been verified by Fourier transform infrared spectroscopy. The bandgap of Ag3PO4 is calculated using kubelka-munk function from the ultra violet-visible diffuse reflectance spectroscopy, the absorption of Ag3PO4 starts from 470 nm. Under simulated visible light irradiation, Ag3PO4 catalyst exhibits good catalytic ability for degrading MB dye.

  4. Occurrence of 210Po and Biological Effects of Low-Level Exposure: The Need for Research

    PubMed Central

    Wiemels, Joseph L.

    2012-01-01

    Background: Polonium-210 (210Po) concentrations that exceed 1 Bq/L in drinking-water supplies have been reported from four widely separated U.S. states where exposure to it went unnoticed for decades. The radionuclide grandparents of 210Po are common in sediments, and segments of the public may be chronically exposed to low levels of 210Po in drinking water or in food products from animals raised in contaminated areas. Objectives: We summarized information on the environmental behavior, biokinetics, and toxicology of 210Po and identified the need for future research. Methods: Potential linkages between environmental exposure to 210Po and human health effects were identified in a literature review. Discussion: 210Po accumulates in the ovaries where it kills primary oocytes at low doses. Because of its radiosensitivity and tendency to concentrate 210Po, the ovary may be the critical organ in determining the lowest injurious dose for 210Po. 210Po also accumulates in the yolk sac of the embryo and in the fetal and placental tissues. Low-level exposure to 210Po may have subtle, long-term biological effects because of its tropism towards reproductive and embryonic and fetal tissues where exposure to a single alpha particle may kill or damage critical cells. 210Po is present in cigarettes and maternal smoking has several effects that appear consistent with the toxicology of 210Po. Conclusions: Much of the important biological and toxicological research on 210Po is more than four decades old. New research is needed to evaluate environmental exposure to 210Po and the biological effects of low-dose exposure to it so that public health officials can develop appropriate mitigation measures where necessary. PMID:22538346

  5. 210Po in Nevada groundwater and its relation to gross alpha radioactivity

    USGS Publications Warehouse

    Seiler, R.L.

    2011-01-01

    Polonium-210 (210Po) is a highly toxic alpha emitter that is rarely found in groundwater at activities exceeding 1 pCi/L. 210Po activities in 63 domestic and public-supply wells in Lahontan Valley in Churchill County in northern Nevada, United States, ranged from 0.01 ± 0.005 to 178 ± 16 pCi/L with a median activity of 2.88 pCi/L. Wells with high 210Po activities had low dissolved oxygen concentrations (less than 0.1 mg/L) and commonly had pH greater than 9. Lead-210 activities are low and aqueous 210Po is unsupported by 210Pb, indicating that the 210Po is mobilized from aquifer sediments. The only significant contributors to alpha particle activity in Lahontan Valley groundwater are 234/238U, 222Rn, and 210Po. Radon-222 activities were below 1000 pCi/L and were uncorrelated with 210Po activity. The only applicable drinking water standard for 210Po in the United States is the adjusted gross alpha radioactivity (GAR) standard of 15 pCi/L. 210Po was not volatile in a Nevada well, but volatile 210Po has been reported in a Florida well. Additional information on the volatility of 210Po is needed because GAR is an inappropriate method to screen for volatile radionuclides. About 25% of the samples had 210Po activities that exceed the level associated with a lifetime total cancer risk of 1× 10−4 (1.1 pCi/L) without exceeding the GAR standard. In cases where the 72-h GAR exceeds the uranium activity by more than 5 to 10 pCi/L, an analysis to rule out the presence of 210Po may be justified to protect human health even though the maximum contaminant level for adjusted GAR is not exceeded.

  6. Energetics of phosphate frameworks containing zinc and cobalt: NaZnPO{sub 4}, NaH(ZnPO{sub 4}){sub 2}, NaZnPO{sub 4}.H{sub 2}O, NaZnPO{sub 4}.4/3 H{sub 2}O, and NaCo{sub x}Zn{sub 1-x}PO{sub 4}.4/3 H{sub 2}O

    SciTech Connect

    Le, So-Nhu; Navrotsky, Alexandra

    2007-09-15

    Differential scanning calorimetry and high temperature oxide melt solution calorimetry were used to study the enthalpy of the {alpha}-{beta} phase transformation of NaZnPO{sub 4} and enthalpies of formation of {alpha}-NaZnPO{sub 4}, NaH(ZnPO{sub 4}){sub 2}, NaZnPO{sub 4}.H{sub 2}O, and NaCo{sub x}Zn{sub 1-x}PO{sub 4}.4/3 H{sub 2}O (x=0, 0.1, 0.2, 0.3). The enthalpies of formation from the oxides of cobalt substituted in NaZnPO{sub 4}.4/3 H{sub 2}O do not depend on cobalt content, confirming similar acid-base interactions for Zn-PO{sub 4} and Co-PO{sub 4}. While water molecules stabilize zinc phosphate frameworks through solvating a cation or forming extra hydrogen bonds, the partial substitution of water for sodium oxide to form NaH(ZnPO{sub 4}){sub 2} represents the formation of an acidic compound with weaker acid-base interactions and less exothermic enthalpy of formation from oxides than Na{sub 2}(ZnPO{sub 4}){sub 2}. - Graphical abstract: Relative stability of NaZnPO{sub 4} dense phases, open frameworks, and hydrated frameworks. Enthalpy of interaction between water and NaZnPO{sub 4} frameworks is presented by reaction: NaZnPO{sub 4} (cr, open framework) + nH{sub 2}O (l) {yields} NaZnPO{sub 4}.nH{sub 2}O (cr, hydrated framework)

  7. 210Po concentration analysis on tobacco and cigarettes in Malaysia

    NASA Astrophysics Data System (ADS)

    Azman, Muhammad Azfar; Rahman, Irman Abdul; Yasir, Muhammad Samudi

    2013-05-01

    Tobacco or better known as the cigarette was smoked since ages. Although many efforts had been made by the Ministry of Health to prevent or reduce the cigarette problem, the smokers still consider that cigarette are not harmful to health. This work is conducted to study the concentration of radionuclides alpha in tobacco and tobacco products in Malaysia. The radionuclide sought in this study is 210Po which is an alpha emitter. The sample used are tobacco and cigarettes, the tobacco samples were taken from tobacco farms in Malaysia while the sample branded cigarettes Marlboro and Gudang Garam were bought in the supermarket. The objectives of this study are to determine the concentration of radionuclides 210Po in tobacco and tobacco products as well as to estimate the radioactivity doses contributing to the smokers in Malaysia. The results for Marlboro cigarettes and Gudang Garam were found to be on the average radionuclide concentration of 210Po is 13.3 mBq/g (Marlboro cigarettes) and 11.9 mBq/g (Gudang Garam). From the total concentration of the cigarette, the estimated annual contribution dose to smokers for every 20 cigarettes smoked per day are 111.9 ± 14.7 μSv/year for Marlboro cigarettes and 100.2 ± 3.3 μSv/year for Gudang Garam cigarettes. The average concentration of radionuclides for tobacco leaf tobacco for each area taken is 3.6 mBq / g for Bachok, 2.4 mBq / g for Tumpat and 3.1 mBq / g for Semerak district.

  8. Atomic Mass and Nuclear Binding Energy for Po-281 (Polonium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-281 (Polonium, atomic number Z = 84, mass number A = 281).

  9. Atomic Mass and Nuclear Binding Energy for Po-277 (Polonium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-277 (Polonium, atomic number Z = 84, mass number A = 277).

  10. Atomic Mass and Nuclear Binding Energy for Po-270 (Polonium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-270 (Polonium, atomic number Z = 84, mass number A = 270).

  11. Atomic Mass and Nuclear Binding Energy for Po-284 (Polonium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-284 (Polonium, atomic number Z = 84, mass number A = 284).

  12. Atomic Mass and Nuclear Binding Energy for Po-276 (Polonium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-276 (Polonium, atomic number Z = 84, mass number A = 276).

  13. Atomic Mass and Nuclear Binding Energy for Po-269 (Polonium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-269 (Polonium, atomic number Z = 84, mass number A = 269).

  14. Atomic Mass and Nuclear Binding Energy for Po-272 (Polonium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-272 (Polonium, atomic number Z = 84, mass number A = 272).

  15. Atomic Mass and Nuclear Binding Energy for Po-266 (Polonium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-266 (Polonium, atomic number Z = 84, mass number A = 266).

  16. Atomic Mass and Nuclear Binding Energy for Po-280 (Polonium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-280 (Polonium, atomic number Z = 84, mass number A = 280).

  17. Atomic Mass and Nuclear Binding Energy for Po-274 (Polonium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-274 (Polonium, atomic number Z = 84, mass number A = 274).

  18. Atomic Mass and Nuclear Binding Energy for Po-273 (Polonium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-273 (Polonium, atomic number Z = 84, mass number A = 273).

  19. Atomic Mass and Nuclear Binding Energy for Po-271 (Polonium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-271 (Polonium, atomic number Z = 84, mass number A = 271).

  20. An emergency bioassay method for (210)Po in urine.

    PubMed

    Guérin, Nicolas; Dai, Xiongxin

    2015-09-01

    A rapid method was developed to efficiently measure (210)Po in urine samples in an emergency situation. Polonium-210 in small urine samples (10 mL) was spontaneously deposited on a stainless steel disc in 1 M HCl at room temperature for 4 h in a polyethylene bottle. The metallic disc was then counted for 4 h by alpha spectrometry. The developed method allowed the preparation of large sample batch in a short time. The method meets the requirements for an emergency bioassay procedure.

  1. Atomic Mass and Nuclear Binding Energy for Po-278 (Polonium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-278 (Polonium, atomic number Z = 84, mass number A = 278).

  2. Atomic Mass and Nuclear Binding Energy for Po-268 (Polonium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-268 (Polonium, atomic number Z = 84, mass number A = 268).

  3. Atomic Mass and Nuclear Binding Energy for Po-282 (Polonium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-282 (Polonium, atomic number Z = 84, mass number A = 282).

  4. Atomic Mass and Nuclear Binding Energy for Po-279 (Polonium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-279 (Polonium, atomic number Z = 84, mass number A = 279).

  5. Atomic Mass and Nuclear Binding Energy for Po-267 (Polonium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-267 (Polonium, atomic number Z = 84, mass number A = 267).

  6. Atomic Mass and Nuclear Binding Energy for Po-283 (Polonium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-283 (Polonium, atomic number Z = 84, mass number A = 283).

  7. Atomic Mass and Nuclear Binding Energy for Po-275 (Polonium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-275 (Polonium, atomic number Z = 84, mass number A = 275).

  8. Small earth station antenna synthesized by a direct PO method

    NASA Astrophysics Data System (ADS)

    Schlobohm, Bernd; Arndt, Fritz

    1990-11-01

    An efficient direct numerical synthesis method for dual offset reflector antennas is described which is based on the physical optics (PO) procedure. The method involves an evolution-strategy optimization algorithm in order to shape both reflectors directly, so as to generate the desired far field with prescribed criteria. The efficiency of the design method is demonstrated by the example of a compact Gregorian dual-offset earth-station antenna with high offset angle (70 deg) and small subreflector size (13 lambda); 75 percent antenna efficiency, 38 dB cross-polarization attenuation, and a very low sidelobe behavior of about 23-25 log theta dBi are achieved.

  9. Hydrogen--deuterium exchange in KD2PO4

    SciTech Connect

    Kucheyev, S O; Felter, T E; Siekhaus, W J; Nelson, A J; Hamza, A V

    2003-11-04

    Depth profiles of {sup 1}H and {sup 2}D in rapidly-grown KD{sub 2x}H{sub 2(1-x)}PO{sub 4} (DKDP) single crystals are studied by elastic recoil detection analysis. Results show that, at ambient conditions, deuteration in the first {approx} 500 nm from the sample surface significantly decreases within the first several days after D{sub 2}O surface polishing. This effect is attributed to the deuterium-hydrogen exchange. The effective diffusion coefficient of this process is strongly dependent on both the degree of deuteration and sample growth conditions. Physical mechanisms of the D/H exchange are discussed.

  10. An emergency bioassay method for (210)Po in urine.

    PubMed

    Guérin, Nicolas; Dai, Xiongxin

    2015-09-01

    A rapid method was developed to efficiently measure (210)Po in urine samples in an emergency situation. Polonium-210 in small urine samples (10 mL) was spontaneously deposited on a stainless steel disc in 1 M HCl at room temperature for 4 h in a polyethylene bottle. The metallic disc was then counted for 4 h by alpha spectrometry. The developed method allowed the preparation of large sample batch in a short time. The method meets the requirements for an emergency bioassay procedure. PMID:26115206

  11. Micro-Raman observation on the H2PO4- association structures in a supersaturated droplet of potassium dihydrogen phosphate (KH2PO4)

    NASA Astrophysics Data System (ADS)

    Syed, Kamran Ajmal; Pang, Shu-Feng; Zhang, Yun; Zhang, Yun-Hong

    2013-01-01

    The efflorescence of an individual KH2PO4 droplet on Teflon substrate was investigated by micro-Raman spectroscopy. With the decrease of relative humidity (RH) from 98.0% to 73.0%, the KH2PO4 droplet lost water gradually and entered into supersaturated state, which was reflected by the area ratio between the water stretching band to the sum of νs-PO2 and νs-P(OH)2 bands of the H2PO4- (A_{H_2 O} /(A_{(ν _s -PO_2 } {+ A}_{ν _s -P(OH)_2 {)}} {)}). In 1.0 mol l-1 KH2PO4 solution, the νs-P(OH)2 and νs-PO2 bands appeared at 877 and 1077 cm-1. In the KH2PO4 droplet, the two bands shifted to 894 and 1039 cm-1 at 98.0% RH, to 899 and 1031 cm-1 at 89.6% RH, and then to 904 and 997 cm-1 at 73.0% RH. Moreover, the aggregation process between the H2PO4- ions was observed from the spectral characteristic of the νs-P(OH)2 band in the concentration process, including the transitions of the H2PO4- ions from monomer in bulk solutions (0.5-1.0 mol l-1) to possible dimers at 98.0% RH and then further to oligomers in the droplet with the RH decrease, which were indicated by the blueshift of the νs-P(OH)2 band and its full width at half-height as a function of the RH. When the RH reached at 72.0%, the anhydrous crystal was obtained. A strong peak appeared at 928 cm-1, implying that the four oxygen atoms of the H2PO4- were all hydrogen bonding through the bridge hydrogen atoms to get the extensive hydrogen-bonded network structure of the H2PO4- association, leading to the symmetric increase of the H2PO4- ion from C2v in dilute solution to quasi-Td in the anhydrous crystal.

  12. Energy transfer from PO excited states to alkali metal atoms in the phosphorus chemiluminescence flame

    PubMed Central

    Khan, Ahsan U.

    1980-01-01

    Phosphorus chemiluminescence under ambient conditions of a phosphorus oxidation flame is found to offer an efficient electronic energy transferring system to alkali metal atoms. The lowest resonance lines, 2P3 / 2,½→2S½, of potassium and sodium are excited by energy transfer when an argon stream at 80°C carrying potassium or sodium atoms intersects a phosphorus vapor stream, either at the flame or in the postflame region. The lowest electronically excited metastable 4IIi state of PO or the (PO[unk]PO)* excimer is considered to be the probable energy donor. The (PO[unk]PO)* excimer results from the interaction of the 4IIi state of one PO molecule with the ground 2IIr state of another. Metastability of the donor state is strongly indicated by the observation of intense sensitized alkali atom fluorescence in the postflame region. PMID:16592925

  13. The sources and fate of (210)Po in the urban air: A review.

    PubMed

    Długosz-Lisiecka, Magdalena

    2016-09-01

    The origin of (210)Po activity and its fluctuations in the air are discussed in this paper. In the case of atmospheric aerosol samples, a comparison of the (210)Po/(210)Pb and (210)Bi/(210)Pb activity ratios makes it possible not only to determine aerosol residence times but also to appraise the contribution of the unsupported (210)Po coming from other sources than (222)Rn decay, such as human industrial activities, especially coal combustion. A simple mathematical method makes it possible to observe the seasonal fluctuations of the anthropogenic excess of (210)Po in the urban air. The average doses of (210)Po intake with food (including drinking water) and inhalation of urban aerosols are usually lower than those from (210)Po intake by cigarette smokers and negligible in comparison to total natural radiation exposure. PMID:27295049

  14. The source of first-cycle capacity loss in LiFePO 4

    NASA Astrophysics Data System (ADS)

    Andersson, A. S.; Thomas, J. O.

    The electrochemical extraction of lithium from solid-state synthesised LiFePO 4 has been studied by neutron powder diffraction. A "coffee-bag" type cell of configuration PO 4> has been charged to 4.1 V, dismantled in a glovebox, and the composite cathode powder sample scraped from the current collector. Two-phase Rietveld refinement gave a triphylite (LiFePO 4) to heterosite (FePO 4) phase-ratio of 18:82. In the absence of significant absorption effects, this ratio is a true representation of the conversion of LiFePO 4 to FePO 4. Possible mechanisms for lithium extraction/insertion during the first-cycle are discussed.

  15. Decay/ingrowth uncertainty correction of (210)Po/(210)Pb in seawater.

    PubMed

    Lin, Wuhui; Ma, Hao; Chen, Liqi; Zeng, Zhi; He, Jianhua; Zeng, Shi

    2014-11-01

    Due to increasing application of (210)Po/(210)Pb in studying particle dynamics, a consistent procedure and calculation to derive accurate and precise result of (210)Po and (210)Pb in seawater should be proposed in the framework of intercalibration by GEOTRACES. The associated uncertainty of radioactivity, which is a significant component of data report, plays a vital role in intercomparison and should be well evaluated. Although measurement uncertainty of laboratory result was well defined in ISO standards and IAEA technical documents, the decay/ingrowth uncertainty correction from laboratory result to in-situ result was less studied. It was demonstrated that the relative uncertainty of in-situ (210)Pb activity was independent of elapsed time and equal to relative uncertainty of laboratory measuring (210)Po activity at second spontaneous deposition date. The relative uncertainty of in-situ (210)Po activity decreases with in-situ activity ratio of (210)Po to (210)Pb and increases with elapsed time between sampling date and separation date, relative uncertainty of laboratory measuring (210)Po activity at first spontaneous deposition date and relative uncertainty of in-situ (210)Pb activity. It was more important to improve precision of (210)Po at first spontaneous deposition date than that of (210)Po at second spontaneous deposition date. To obtain a desirable relative uncertainty of in-situ (210)Po activity, the maximum allowing elapsed time for (210)Po, which was important for sampling strategy making and quality assurance, was calculated by in-situ activity ratio of (210)Po to (210)Pb and precision of analytical method for (210)Po. The methodology of decay/ingrowth uncertainty correction could also be applied for other radionuclide pairs ((234)Th/(238)U, (90)Y/(90)Sr, (210)Bi/(210)Pb), sample matrixes (aerosols), and disciplines. PMID:24992240

  16. Decay/ingrowth uncertainty correction of (210)Po/(210)Pb in seawater.

    PubMed

    Lin, Wuhui; Ma, Hao; Chen, Liqi; Zeng, Zhi; He, Jianhua; Zeng, Shi

    2014-11-01

    Due to increasing application of (210)Po/(210)Pb in studying particle dynamics, a consistent procedure and calculation to derive accurate and precise result of (210)Po and (210)Pb in seawater should be proposed in the framework of intercalibration by GEOTRACES. The associated uncertainty of radioactivity, which is a significant component of data report, plays a vital role in intercomparison and should be well evaluated. Although measurement uncertainty of laboratory result was well defined in ISO standards and IAEA technical documents, the decay/ingrowth uncertainty correction from laboratory result to in-situ result was less studied. It was demonstrated that the relative uncertainty of in-situ (210)Pb activity was independent of elapsed time and equal to relative uncertainty of laboratory measuring (210)Po activity at second spontaneous deposition date. The relative uncertainty of in-situ (210)Po activity decreases with in-situ activity ratio of (210)Po to (210)Pb and increases with elapsed time between sampling date and separation date, relative uncertainty of laboratory measuring (210)Po activity at first spontaneous deposition date and relative uncertainty of in-situ (210)Pb activity. It was more important to improve precision of (210)Po at first spontaneous deposition date than that of (210)Po at second spontaneous deposition date. To obtain a desirable relative uncertainty of in-situ (210)Po activity, the maximum allowing elapsed time for (210)Po, which was important for sampling strategy making and quality assurance, was calculated by in-situ activity ratio of (210)Po to (210)Pb and precision of analytical method for (210)Po. The methodology of decay/ingrowth uncertainty correction could also be applied for other radionuclide pairs ((234)Th/(238)U, (90)Y/(90)Sr, (210)Bi/(210)Pb), sample matrixes (aerosols), and disciplines.

  17. Redetermination of β-Ba(PO3)2.

    PubMed

    Weil, Matthias

    2014-02-01

    In comparison with the previous structure determination of the β-modification of barium catena-polyphosphate that was based on Weissenberg film data [Grenier et al. (1967 ▶). Bull. Soc. Fr. Minéral. Cristallogr. 90, 24-31], the current CCD-data-based redetermination reveals all atoms with anisotropic displacement parameters, standard uncertainties for the atomic coordinates, and the determination of the absolute structure. Moreover, a much higher accuracy in terms of the bond-length distribution for the polyphosphate chain, with two shorter and two longer P-O distances, was achieved. The structure consists of polyphosphate chains extending parallel to [100] with a periodicity of two PO4 tetra-hedra. The Ba(2+) cations are located between the chains and are surrounded by ten O atoms in the form of a distorted coordination polyhedron, with Ba-O distances ranging from 2.765 (3) to 3.143 (3) Å, also reflecting the higher precision of the current redetermination.

  18. Assessment of river Po sediment quality by micropollutant analysis.

    PubMed

    Camusso, Marina; Galassi, Silvana; Vignati, Davide

    2002-05-01

    Trace metals, PCB congeners and DDT homologues were determined in composite sediment samples collected from 10 representative sites along the river Po in two separate seasons. The aim was to identify the most anthropogenically impacted areas for future monitoring programmes and to aid development of Italian sediment quality criteria. The surface samples were collected during low flow conditions. Trace metal concentrations were assayed by electrothermal (Cd, Co, Cr, Cu, Ni, Pb), flame (Fe, Mn, Zn) or hydride generation (As) atomic absorption spectrometry after microwave assisted acid digestion. Hg was determined on solid samples by automated analyser. Organic microcontaminants were determined by gas-chromatography with 63Ni electron capture detector after Soxhlet extraction. Concentrations of trace metals, total PCB and DDT homologues showed two distinct peaks at the sites immediately downstream of Turin and Milan, respectively, and in each case decreased progressively further downstream. Principal component analysis identified three major factors (from a multi-dimensional space of 35 variables) which explained 85-90% of the total observed variance. The first and second factors corresponded to anthropogenic inputs and geological factors on sediment quality; the third included seasonal processes of minor importance. Sediment quality assessment identified Cd, Cu, Hg, Pb, Zn and organic microcontaminants as posing the most serious threats to river sediment quality. A reference site within the Po basin provided useful background values. Moderate pollution by organochlorine compounds was ascribed both to local sources and to atmospheric deposition. PMID:12153015

  19. STEREO-IMPACT E/PO: Getting Ready for Launch!

    NASA Astrophysics Data System (ADS)

    Mendez, B. J.; Peticolas, L. M.; Craig, N.

    2005-12-01

    The Solar Terrestrial Relations Observatory (STEREO) is scheduled for launch in April/May 2006. STEREO will study the Sun with two spacecraft on either side of Earth in orbit around the Sun. The primary science goal is to understand the nature of Coronal Mass Ejections (CMEs). The E/PO program for the IMPACT suite of instruments aboard the two crafts is planning several activities leading up to launch to raise awareness and interest in the mission and its scientific discoveries. We will be participating in NASA's Sun-Earth day events which are scheduled to coincide with a total solar eclipse in March. This event offers a good opportunity to engage the public in STEREO science, because an eclipse allows one to see the solar corona from where CMEs erupt. We will be conducting teacher workshops locally in California and also at the annual conference of the National Science Teachers Association. At these workshops, we will focus on the basics of magnetism and then its connection to CMEs and Earth's magnetic field, leading to the questions STEREO scientists hope to answer. In addition, we will be working with NASA's Public Relations office to ensure that STEREO E/PO programs are highlighted in press releases about the mission.

  20. {sup 210}Po and {sup 210}Pb in Forest Soil and in Wild Berries in Finland

    SciTech Connect

    Vaaramaa, Kaisa; Lehto, Jukka; Solatie, Dina; Aro, Lasse

    2008-08-07

    The behaviour of {sup 210}Po and {sup 210}Pb was investigated in forests in the Southern Finland site and in the Northern Finland site. Sampling sites were in Scots pine (Pinus sylvestris) forests. Maximum activities of {sup 210}Po and {sup 210}Pb in soil columns were found in organic layers. According to preliminary results of wild berry samples, the lowest {sup 210}Po concentrations were found in berries. The highest concentration of {sup 210}Po was found in stems of the blueberry (Vaccinium myrtillus) and the lingonberry (Vaccinium vitis-idaea) samples.

  1. The importance of acid digestion of urine prior to spontaneous deposition of 210Po.

    PubMed

    Fellman, A; Ralston, L; Hickman, D; Ayres, L; Cohen, N; Spitz, H; Robinson, B

    1989-10-01

    Historically, radiochemical analysis of 210Po in urine has used spontaneous deposition of the nuclide directly from raw urine onto a suitable metal disc. Consequently, the urinary excretion fraction for Po in some current metabolic and dosimetric models is based on studies which inherently assume that metabolized (i.e., filtered out of the blood by the kidneys) 210Po is plated with the same efficiency as tracer 210Po which has been added to urine samples. Urine samples collected after intravenous administration of 210Po citrate to two species of nonhuman primates were divided and simultaneously analyzed via two methods: the historical procedure of plating 210Po from raw urine for one sample and a method which includes the addition of 208Po tracer and sample digestion with concentrated HNO3 prior to 210Po deposition for the other sample. A more significant amount of 210Po was consistently recovered when the urine was wet ashed then when it was not wet ashed. A temporal relationship was found to describe the change in the ratio of the deposition recoveries for the two methods. Possible mechanisms for this phenomenon and its dosimetric implications are discussed. PMID:2507478

  2. Binary and ternary Po-containing molecules relevant for LBE cooled reactors at operating temperature

    NASA Astrophysics Data System (ADS)

    Van Yperen-De Deyne, Andy; Rijpstra, Kim; Waroquier, Michel; Van Speybroeck, Veronique; Cottenier, Stefaan

    2015-03-01

    Quantum-chemical calculations at several levels of theory were used to assess the stability at different temperatures of a set of 13 binary and ternary Po-containing molecules that could possibly be formed in an environment with lead, bismuth, oxygen and water. The conclusions are that especially PoPb, PbPoO and PoOH and to a lesser extent Po2 and PoO are stable. These small molecules are therefore likely to be found near the Lead-Bismuth eutectic (LBE) coolant at operational temperatures in a heavy liquid metal cooled fission reactor. In contrast, Po3 and PoBi are unlikely to be present under the assumed conditions. Several stability criteria, such as the dissociation into free atoms or into molecular fragments at realistic Po-concentrations or in the thermodynamic limit are discussed at different temperatures. The results obtained with a medium level of theory (Density Functional Theory, PBE0 with relativistic effective core potentials) show good qualitative correspondence with calculations performed at a much higher level of theory (Multi Reference Configuration Interaction, with spin-orbit coupling and scalar relativistic Hamiltonian).

  3. Shell-model description of sup 211 Bi(. beta. sup minus ) sup 211 Po and sup 211 At(EC) sup 211 Po and the spectroscopy of sup 211 Po

    SciTech Connect

    Warburton, E.K. )

    1991-10-01

    A recent treatment of first-forbidden {beta}{sup {minus}} decay in the lead region is extended to {beta}{sup +} decay and electron capture. The modified Kuo-Herling shell-model interaction recently described by Warburton and Brown is used to calculate wave functions and observables for {sup 211}Po. The log{ital f}{sub 0}{ital t} values for the {sup 211}Bi(9/2{sup {minus}}){r arrow}{sup 211}Po(9/2{sup +}) {beta}{sup {minus}} transition and the electron capture of {sup 211}At(9/2{sup {minus}}) into the 9/2 {sub 1}{sup +} and 11/2 {sub 1}{sup +} states of {sup 211}Po are predicted to be 6.008, 5.891, and 5.850 as compared to the experimental values of 6.026{plus minus}0.017, 5.960{plus minus}0.008, and 5.831{plus minus}0.090, respectively. The wave functions and spectrum of {sup 211}Po are calculated in the Kuo-Herling model space. The yrast spectrum is presented for comparison to anticipated results from fusion-evaporation reaction studies. The experimental {sup 210}Po({ital d},{ital p}){sup 211}Po spectroscopic factors are quite accurately reproduced.

  4. Important Variation in Vibrational Properties of LiFePO4 and FePO4 Induced by Magnetism.

    PubMed

    Seifitokaldani, Ali; Gheribi, Aïmen E; Phan, Anh Thu; Chartrand, Patrice; Dollé, Mickaël

    2016-01-01

    A new thermodynamically self-consistent (TSC) method, based on the quasi-harmonic approximation (QHA), is used to obtain the Debye temperatures of LiFePO4 (LFP) and FePO4 (FP) from available experimental specific heat capacities for a wide temperature range. The calculated Debye temperatures show an interesting critical and peculiar behavior so that a steep increase in the Debye temperatures is observed by increasing the temperature. This critical behavior is fitted by the critical function and the adjusted critical temperatures are very close to the magnetic phase transition temperatures in LFP and FP. Hence, the critical behavior of the Debye temperatures is correlated with the magnetic phase transitions in these compounds. Our first-principle calculations support our conjecture that the change in electronic structures, i.e. electron density of state and electron localization function, and consequently the change in thermophysical properties due to the magnetic transition may be the reason for the observation of this peculiar behavior of the Debye temperatures. PMID:27604551

  5. Important Variation in Vibrational Properties of LiFePO4 and FePO4 Induced by Magnetism.

    PubMed

    Seifitokaldani, Ali; Gheribi, Aïmen E; Phan, Anh Thu; Chartrand, Patrice; Dollé, Mickaël

    2016-09-08

    A new thermodynamically self-consistent (TSC) method, based on the quasi-harmonic approximation (QHA), is used to obtain the Debye temperatures of LiFePO4 (LFP) and FePO4 (FP) from available experimental specific heat capacities for a wide temperature range. The calculated Debye temperatures show an interesting critical and peculiar behavior so that a steep increase in the Debye temperatures is observed by increasing the temperature. This critical behavior is fitted by the critical function and the adjusted critical temperatures are very close to the magnetic phase transition temperatures in LFP and FP. Hence, the critical behavior of the Debye temperatures is correlated with the magnetic phase transitions in these compounds. Our first-principle calculations support our conjecture that the change in electronic structures, i.e. electron density of state and electron localization function, and consequently the change in thermophysical properties due to the magnetic transition may be the reason for the observation of this peculiar behavior of the Debye temperatures.

  6. Important Variation in Vibrational Properties of LiFePO4 and FePO4 Induced by Magnetism

    NASA Astrophysics Data System (ADS)

    Seifitokaldani, Ali; Gheribi, Aïmen E.; Phan, Anh Thu; Chartrand, Patrice; Dollé, Mickaël

    2016-09-01

    A new thermodynamically self-consistent (TSC) method, based on the quasi-harmonic approximation (QHA), is used to obtain the Debye temperatures of LiFePO4 (LFP) and FePO4 (FP) from available experimental specific heat capacities for a wide temperature range. The calculated Debye temperatures show an interesting critical and peculiar behavior so that a steep increase in the Debye temperatures is observed by increasing the temperature. This critical behavior is fitted by the critical function and the adjusted critical temperatures are very close to the magnetic phase transition temperatures in LFP and FP. Hence, the critical behavior of the Debye temperatures is correlated with the magnetic phase transitions in these compounds. Our first-principle calculations support our conjecture that the change in electronic structures, i.e. electron density of state and electron localization function, and consequently the change in thermophysical properties due to the magnetic transition may be the reason for the observation of this peculiar behavior of the Debye temperatures.

  7. Ion-ion recombination of H3O+ with I- and PO3-/PO2- in flames

    NASA Astrophysics Data System (ADS)

    Chow, Christine C. Y.; Goodings, John M.

    1996-03-01

    Ion-ion recombination coefficients ki have been measured in a fuel-rich CH4---O2---Ar flame at 2582 K and atmospheric pressure for the H3O+ cation recombining with anions of iodine and phosphorus, relative to the electron-ion recombination of H3O+, assuming a rate coefficient ke of 4.1 × 10-7 cm3 molecule-1 s-1. Positive and negative ions were observed by sampling the flame through a nozzle into a mass spectrometer. Recombination coefficients were determined from the slopes of plots of the sampled inverse total positive ion current versus distance along the flame axis. For the H3O+/I- recombination, ki = (3.0 ± 1.0) × 10-8 cm3 molecule-1 s-1, considerably higher than the value of (1.2 ± 0.7) × 10-8 determined previously by other workers. A possible reason for the discrepancy involves the cooling which results from flame inhibition by iodine. With phosphorus additive, two major anions PO3- and PO2- jointly recombine with H3O+ to give a "global" rate coefficient ki = (3.7 ± 1.4) × 10-8 cm3 molecule-1 s-1.

  8. Important Variation in Vibrational Properties of LiFePO4 and FePO4 Induced by Magnetism

    PubMed Central

    Seifitokaldani, Ali; Gheribi, Aïmen E.; Phan, Anh Thu; Chartrand, Patrice; Dollé, Mickaël

    2016-01-01

    A new thermodynamically self-consistent (TSC) method, based on the quasi-harmonic approximation (QHA), is used to obtain the Debye temperatures of LiFePO4 (LFP) and FePO4 (FP) from available experimental specific heat capacities for a wide temperature range. The calculated Debye temperatures show an interesting critical and peculiar behavior so that a steep increase in the Debye temperatures is observed by increasing the temperature. This critical behavior is fitted by the critical function and the adjusted critical temperatures are very close to the magnetic phase transition temperatures in LFP and FP. Hence, the critical behavior of the Debye temperatures is correlated with the magnetic phase transitions in these compounds. Our first-principle calculations support our conjecture that the change in electronic structures, i.e. electron density of state and electron localization function, and consequently the change in thermophysical properties due to the magnetic transition may be the reason for the observation of this peculiar behavior of the Debye temperatures. PMID:27604551

  9. Magnetic relaxation in Zn(PO3)2·Er(PO3)3 glass

    NASA Astrophysics Data System (ADS)

    Orendáč, M.; Tibenská, K.; Čižmár, E.; Tkáč, V.; Orendáčová, A.; Holubová, J.; Černošek, Z.; Černošková, E.

    2016-08-01

    The results of experimental studies of alternating (ac) magnetic susceptibility and specific heat of Zn(PO3)2·Er(PO3)3 glass are reported. Despite a high concentration of magnetic Er(III) ions the analysis of ac susceptibility ruled out the formation of a spin glass state in the used range of temperatures. Two relaxation processes were identified. The first one is thermally activated with a crossover in its temperature dependence observed at nominally 7 K. The relaxation at lower temperatures seems to be governed by a direct process with pronounced effect of phonon bottleneck. Striking deceleration of spin dynamics with increasing temperature found above 7 K is tentatively attributed to overcoming Ioffe - Regel crossover and strong scattering of acoustic phonons on local modes. Simplified prediction derived from a soft-mode-dynamics model confirms the presence of the boson peak observed in specific heat data and reasonably predicts the temperature of the crossover. The second process is consistent with a cross - tunneling relaxation. The obtained results suggest that magnetic doping of glasses and studying magnetic relaxation may represent an alternative tool for the investigation of lattice modes in glasses.

  10. Synthesis and characterization of CdS/BiPO{sub 4} heterojunction photocatalyst

    SciTech Connect

    Chen, Daimei Kuang, Zheng; Zhu, Qian; Du, Yue; Zhu, Honglei

    2015-06-15

    Highlights: • A CdS/BiPO{sub 4} heterojunction was prepared by the solvothermal method. • The CdS/BiPO{sub 4} composite has the higher photocatalytic activity than the individual ones. • The optimal mass ratio of CdS to BiPO{sub 4} was 0.5. • The heterojunction structure of CdS/BiPO{sub 4} induces an effective electron–hole separation. - Abstract: A series of CdS/BiPO{sub 4} heterojunction photocatalysts with the visible-light response were synthesized by the solvothermal method. The resulting products were characterized by X-ray diffraction, Transmission electron microscopy, X-ray photoelectron spectroscopy, and UV–vis diffuse reflection spectroscopy. CdS nanoparticles with the size at range of 5–7 nm were immobilized on the surface of BiPO{sub 4} nanorods. The CdS/BiPO{sub 4} composite exhibited much higher photodegradation rate of methylene blue under visible light irradation compared to the pure CdS and BiPO{sub 4}. The optimal mass ratio of CdS to BiPO{sub 4} was 0.5, the photodegradation rate of which is 2.1 times higher than that of CdS. The enhancement of photocatalytic activity is attributed to the heterojunction structure of CdS/BiPO{sub 4} composite which induced the effective electron–hole separation between CdS and BiPO{sub 4}.

  11. Tools for Scientist Engagement in E/PO: NASA SMD Community Workspace and Online Resources

    NASA Astrophysics Data System (ADS)

    Dalton, H.; Shipp, S. S.; Grier, J.; Gross, N. A.; Buxner, S.; Bartolone, L.; Peticolas, L. M.; Woroner, M.; Schwerin, T. G.

    2014-12-01

    The Science Mission Directorate (SMD) Science Education and Public Outreach (E/PO) Forums are here to help you get involved in E/PO! The Forums have been developing several online resources to support scientists who are - or who are interested in becoming - involved in E/PO. These include NASA Wavelength, EarthSpace, and the SMD E/PO online community workspace. NASA Wavelength is the one-stop shop of all peer-reviewed NASA education resources to find materials you - or your audiences - can use. Browse by audience (pre-K through 12, higher education, and informal education) or topic, or choose to search for something specific by keyword and audience. http://nasawavelength.org. EarthSpace, an online clearinghouse of Earth and space materials for use in the higher education classroom, is driven by a powerful search engine that allows you to browse the collection of resources by science topic, audience, type of material or key terms. All materials are peer-reviewed before posting, and because all submissions receive a digital object identifier (doi), submitted materials can be listed as publications. http://www.lpi.usra.edu/earthspace. The SMD E/PO online community workspace contains many resources for scientists. These include one-page guides on how to get involved, tips on how to make the most of your time spent on E/PO, and sample activities, as well as news on funding, policy, and what's happening in the E/PO community. The workspace also provides scientists and the public pathways to find opportunities for participation in E/PO, to learn about SMD E/PO projects and their impacts, to connect with SMD E/PO practitioners, and to explore resources to improve professional E/PO practice, including literature reviews, information about the Next Generation Science Standards, and best practices in evaluation and engaging diverse audiences. http://smdepo.org.

  12. Chemical characterization of springtime submicrometer aerosol in Po Valley, Italy

    NASA Astrophysics Data System (ADS)

    Saarikoski, S.; Carbone, S.; Decesari, S.; Giulianelli, L.; Angelini, F.; Canagaratna, M.; Ng, N. L.; Trimborn, A.; Facchini, M. C.; Fuzzi, S.; Hillamo, R.; Worsnop, D.

    2012-09-01

    The chemistry of submicron particles was investigated at San Pietro Capofiume (SPC) measurement station in the Po Valley, Italy, in spring 2008. The measurements were performed by using both off-line and on-line instruments. Organic carbon (OC) and elemental carbon, organic acids and biomass burning tracers were measured off-line by using a 24-h PM1 filter sampling. More detailed particle chemistry was achieved by using a Aerodyne high resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and analyzing the data by positive matrix factorization (PMF). Oxalic acid had the highest concentrations of organic acids (campaign-average 97.4 ng m-3) followed by methane sulfonic, formic, malonic, and malic acids. Samples were also analyzed for glyoxylic, succinic, azelaic and maleic acids. In total, the nine acids composed 1.9 and 3.8% of OC and water-soluble OC, respectively (average), in terms of carbon atoms. Levoglucosan concentration varied from 17.7 to 495 ng m-3 with the concentration decreasing in the course of the campaign most likely due to the reduced use of domestic heating with wood. Six factors were found for organic aerosol (OA) at SPC by PMF: hydrocarbon-like OA (HOA), biomass burning OA (BBOA), nitrogen-containing OA (N-OA) and three different oxygenated OAs (OOA-a, OOA-b and OOA-c). Most of the OA mass was composed of OOA-a, HOA and OOA-c (26, 24 and 22%, respectively) followed by OOA-b (13%), BBOA (8%) and N-OA (7%). As expected, OOAs were the most oxygenated factors with organic matter:organic carbon (OM : OC) ratios ranging from 1.9 to 2.2. The diurnal variability of the aerosol chemical composition was greatly affected by the boundary layer meteorology. Specifically, the effect of the nocturnal layer break-up in morning hours was most evident for nitrate and N-OA indicating that these compounds originated mainly from the local sources in the Po Valley. For sulfate and OOA-a the concentration did not change during the break-up suggesting their

  13. Chemical characterization of springtime submicrometer aerosol in Po Valley, Italy

    NASA Astrophysics Data System (ADS)

    Saarikoski, S.; Carbone, S.; Decesari, S.; Giulianelli, L.; Angelini, F.; Teinilä, K.; Canagaratna, M.; Ng, N. L.; Trimborn, A.; Facchini, M. C.; Fuzzi, S.; Hillamo, R.; Worsnop, D.

    2012-03-01

    The chemistry of submicron particles was investigated at San Pietro Capofiume (SPC) measurement station in the Po Valley, Italy, in spring 2008. The measurements were performed by using both off-line and on-line instruments. Organic carbon (OC) and elemental carbon, organic acids and biomass burning tracers were measured off-line by using a 24-h PM1 filter sampling. More detailed particle chemistry was achieved by using an Aerodyne high resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and analyzing the data by positive matrix factorization (PMF). Oxalic acid had the highest concentrations of organic acids (campaign-average 97.4 ng m-3) followed by methane sulfonic, formic, malonic, and malic acids. Samples were also analyzed for glyoxylic, succinic, azelaic and maleic acids. In total, the nine acids composed 1.9 and 3.8% of OC and water-soluble OC, respectively (average), in terms of carbon atoms. Levoglucosan concentration varied from 17.7 to 495 ng m-3 with the concentration decreasing in the course of the campaign most likely due to the reduced use of domestic heating with wood. Six factors were found for organic aerosol (OA) at SPC by PMF: hydrocarbon-like OA (HOA), biomass burning OA (BBOA), nitrogen-containing OA (N-OA) and three different oxygenated OAs (OOA-a, OOA-b and OOA-c). Most of the OA mass was composed of OOA-a, HOA and OOA-c (26, 24 and 22%, respectively) followed by OOA-b (13%), BBOA (8%) and N-OA (7%). As expected, OOAs were the most oxygenated factors with organic matter:organic carbon (OM:OC) ratios ranging from 1.9 to 2.2. The diurnal variability of the aerosol chemical composition was greatly affected by the boundary layer meteorology. Specifically, the effect of the nocturnal layer break-up in morning hours was most evident for nitrate and N-OA indicating that these compounds originated mainly from the local sources in the Po Valley. For sulfate and OOA-a the concentration did not change during the break-up suggesting their

  14. Structure and electrochemistry of NaFePO{sub 4} and Na{sub 2}FePO{sub 4}F cathode materials prepared via mechanochemical route

    SciTech Connect

    Kosova, N.V.; Podugolnikov, V.R.; Devyatkina, E.T.; Slobodyuk, A.B.

    2014-12-15

    Highlights: • Na{sub 2}FePO{sub 4}F is prepared by mechanochemically assisted solid state synthesis. • The crystal and local structure are studied by XRPD, FTIR, Mössbauer, and NMR. • Na{sup +}/Li{sup +} ion exchange is completed with the formation of NaLiFePO{sub 4}F. • The average D{sub Li} (10{sup −15} cm{sup 2} s{sup −1}) is determined from GITT measurements. - Abstract: Nanostructured NaFePO{sub 4} (space group Pmnb) and Na{sub 2}FePO{sub 4}F (space group Pbcn) were prepared by a quick and facile mechanochemically assisted solid state synthesis. Low-crystalline Na{sub 2}FePO{sub 4}F was formed as a result of direct mechanochemical reaction of NaFePO{sub 4} with NaF. It crystallizes upon subsequent heating to 600 °C and decomposes at higher temperatures. Crystal and local structure were analyzed by XRD using Rietveld refinement, FTIR, Mössbauer, and NMR spectroscopy. Electrochemical properties were studied by galvanostatic cycling in lithium cells and GITT. Although NaFePO{sub 4} showed some electrochemical activity, neither electrochemical nor chemical Na{sup +}/Li{sup +} exchange was observed by XRD. On contrary, electrochemical and chemical Na{sup +}/Li{sup +} ion exchange occurred in the case of Na{sub 2}FePO{sub 4}F and accomplished with the NaLiFePO{sub 4}F formation. Li{sup +} diffusion coefficient in NaLiFePO{sub 4}F at different delithiated/lithiated states was determined from GITT. Carbon-coated Na{sub 2}FePO{sub 4}F shows discharge capacity of 116 mA h g{sup −1} at 0.1 C rate within the 2.0–4.2 V voltage range and a good cyclability.

  15. Evaluation of uncertainty and detection limits in 210Pb and 210Po measurement in water by alpha spectrometry using 210Po spontaneous deposition onto a silver disk.

    PubMed

    Fernández, Pedro L; Gómez, José; Ródenas, Carmen

    2012-04-01

    An easy and accurate method for the determination of (210)Pb and (210)Po in water using (210)Po spontaneous deposition onto a silver disk is proposed and assessed for its detection capabilities according to the ISO Guide for the expression of uncertainty in measurement (GUM) and ISO Standard 11929-7 concerning the evaluation of the characteristic limits for ionizing radiation measurements. The method makes no assumption on the initial values of the activity concentrations of (210)Pb, (210)Bi and (210)Po in the sample to be analyzed, and is based on the alpha spectrometric measurement of (210)Po in two different aliquots: the first one measured five weeks after the sampling date to ensure radioactive equilibrium between (210)Pb and (210)Bi and the second after a sufficient time for the ingrowth of (210)Po from (210)Pb to be significant. As shown, for a recommended time interval of seven months between (210)Po measurements, the applicability of the proposed method is limited to water samples with a (226)Ra to (210)Pb activity ratio C(Ra)/C(Pb) ≤ 4, as usual in natural waters. Using sample and background counting times of 24h and 240 h, respectively, the detection limit of the activity concentration of each radionuclide at the sampling time for a 1L sample typically varies between 0.7 and 16 mBq L(-1) for (210)Pb in water samples with an initial activity of (210)Po in the range 0-200 mBq L(-1), and between 0.6 and 8.5 mBq L(-1) for (210)Po in water samples with an initial activity of (210)Pb in the same range.

  16. Spectroscopy of {sup 193,195,197}Po

    SciTech Connect

    Fotiades, N.; Cizewski, J.A.; McNabb, D.P.; Ding, K.Y.; Davids, C.N.; Janssens, R.V.; Seweryniak, D.; Carpenter, M.P.; Amro, H.; Decrock, P.; Reiter, P.; Nisius, D.; Brown, L.T.; Fischer, S.; Lauritsen, T.; Wauters, J.; Bingham, C.R.; Huyse, M.; Andreyev, A.; Seweryniak, D.; Conticchio, L.F.; Brown, L.T.

    1997-08-01

    Excited states built on the 13/2{sup +} isomers of the odd-mass {sup 193,195,197}Po isotopes have been observed via in-beam {gamma}-ray spectroscopy. The {alpha} radioactivity of these isotopes has been used to tag {gamma}-ray transitions following the {sup A}Er+164 MeV {sup 32}S reactions, where A=164, 166, 167, 168, and 170. Prompt {gamma} radiation was measured by ten Compton-suppressed Ge detectors at the target position and the Fragment Mass Analyzer was used to select evaporation residues. The results are compared with the first excited states of the heavier odd-mass polonium isotopes and of the even-mass cores. {copyright} {ital 1997} {ital The American Physical Society}

  17. PO*WW*ER mobile treatment unit process hazards analysis

    SciTech Connect

    Richardson, R.B.

    1996-06-01

    The objective of this report is to demonstrate that a thorough assessment of the risks associated with the operation of the Rust Geotech patented PO*WW*ER mobile treatment unit (MTU) has been performed and documented. The MTU was developed to treat aqueous mixed wastes at the US Department of Energy (DOE) Albuquerque Operations Office sites. The MTU uses evaporation to separate organics and water from radionuclides and solids, and catalytic oxidation to convert the hazardous into byproducts. This process hazards analysis evaluated a number of accident scenarios not directly related to the operation of the MTU, such as natural phenomena damage and mishandling of chemical containers. Worst case accident scenarios were further evaluated to determine the risk potential to the MTU and to workers, the public, and the environment. The overall risk to any group from operation of the MTU was determined to be very low; the MTU is classified as a Radiological Facility with low hazards.

  18. Comparison of LiFePO4 from different sources

    SciTech Connect

    Striebel, Kathryn; Shim, Joongpyo; Srinivasan, Venkat; Newman, John

    2003-11-25

    The lithium iron phosphate chemistry is plagued by the poor conductivity and slow lithium diffusion in the solid phase. In order to alleviate these problems, various research groups have adopted different strategies including decreasing the particle sizes, increasing the carbon content, and adding dopants. In this study we obtained LiFePO4 electrodes from six different sources and used a combined model-experimental approach to compare the performance. Samples ranged from one with no carbon coating to one with 15 percent coating. In addition, particle sizes varied by as much as a order of magnitude between samples. The study detailed in this manuscript allows us to provide insight into the relative importance of the conductivity of the samples compared to the particle size, the impact of dopant on performance and ideas for making materials in order to maximize the power capability of this chemistry.

  19. Comparison of LiFePO4 from different sources

    SciTech Connect

    Striebel, Kathryn; Shim, Joongpyo; Srinivasan, Venkat; Newman, John

    2004-06-21

    The lithium iron phosphate chemistry is plagued by the poor conductivity and slow diffusion in the solid phase. In order to alleviate these problems, various research groups have adopted different strategies including decreasing the particle sizes, increasing the carbon content, and adding dopants. In this study, we obtained LiFePO{sub 4} powders and/or electrodes from six different sources and used a combined model-experimental approach to compare the performance. Samples ranged from 0.4% to 15% ''in-situ'' carbon. In addition, particle sizes varied by as much as an order of magnitude between samples. The study detailed in this manuscript allows us to provide insight into the relative importance of the conductivity of the samples compared to the particle size, the impact of having a distribution in particle sizes, and ideas for making materials in order to maximize the power capability of this chemistry.

  20. Excretion rates of 210Po and 210Pb in Prague inhabitants.

    PubMed

    Hölgye, Zoltán

    2013-01-01

    Excretion rates of (210)Po and (210)Pb in the urine were investigated in 40 healthy inhabitants of Prague (22 males, 18 females, age: 23-70 y, non-smokers). In 20 inhabitants the excretion rates of (210)Po and (210)Pb in faeces were also studied. The mean urinary excretion rates of (210)Po and (210)Pb were 4.1 and 6.0 mBq d(-1), respectively. It was demonstrated, statistically, that the urinary excretion rates of (210)Po and (210)Pb are higher in men than those in women. The highest excretion rates of (210)Po and (210)Pb found in the participants were 10.8 and 16.6 mBq d(-1), respectively. The mean activity ratio of (210)Po/(210)Pb in the urine was 0.73. The mean excretion rates of (210)Po and (210)Pb in faeces were 56.5 and 54.6 mBq d(-1). The mean activity ratio of (210)Po/(210)Pb in faeces was 1.0.

  1. Complete Genome Sequence of the Plant Pathogen Ralstonia solanacearum Strain Po82 ▿

    PubMed Central

    Xu, Jin; Zheng, Hua-jun; Liu, Lei; Pan, Zhe-chao; Prior, Philippe; Tang, Biao; Xu, Jing-sheng; Zhang, Hao; Tian, Qian; Zhang, Li-qing; Feng, Jie

    2011-01-01

    Ralstonia solanacearum strain Po82, a phylotype IIB/sequevar 4 strain, was found to be pathogenic to both solanaceous plants and banana. Here, we report the complete genome sequence of Po82 and its comparison with seven published R. solanacearum genomes. PMID:21685279

  2. Amphiphilic carbonaceous material-intervened solvothermal synthesis of LiFePO4

    NASA Astrophysics Data System (ADS)

    Chen, Ming-ming; Ma, Qian-qian; Wang, Cheng-yang; Sun, Xin; Wang, Li-qun; Zhang, Cui

    2014-10-01

    LiFePO4 samples with preferred facets on the ac plane were prepared by the solvothermal method with or without well-dispersed amphiphilic carbonaceous material (ACM). The effects of ACM on the particle morphology, crystal orientation and electrochemical reactivity of the prepared LiFePO4 nanoparticles were investigated in detail. ACM serves a dual purpose. One purpose is facilitating the plate-like morphologies of LiFePO4 nanoparticles parallel to the bPnma axis by decreasing the surface energy of (010) facets of newly created LiFePO4 nuclei. The other purpose is suppressing crystal growth along the [010] direction by adhering onto the (010) surface of LiFePO4 nanoplates. Furthermore, ACM coating was performed and optimized using a carbon coating precursor. The electrochemical properties of the prepared LiFePO4 particles were characterized by cyclic voltammetry (CV) and galvanostatic charge-discharge cycling tests. After the optimized coating of ACM, the ACM-intervened LiFePO4 composite was observed to deliver discharge capacities of 151.3 mAh g-1 at 1C and 132.2 mAh g-1 at 10C. Even after 1000 cycles at a high rate of 10C, the LiFePO4 cathode could maintain 80% of its initial capacity.

  3. Modeling pO(2) distributions in the bone marrow hematopoietic compartment. I. Krogh's model.

    PubMed Central

    Chow, D C; Wenning, L A; Miller, W M; Papoutsakis, E T

    2001-01-01

    Human bone marrow (BM) is a tissue of complex architectural organization, which includes granulopoietic loci, erythroblastic islets, and lymphocytic nodules. Oxygen tension (pO(2)) is an important determinant of hematopoietic stem and progenitor cell proliferation and differentiation. Thus, understanding the impact of the BM architectural organization on pO(2) levels in extravascular hematopoietic tissue is an important biophysical problem. However, currently it is impossible to measure pO(2) levels and their spatial variations in the BM. Homogeneous Kroghian models were used to estimate pO(2) distribution in the BM hematopoietic compartment (BMHC) and to conservatively simulate pO(2)-limited cellular architectures. Based on biophysical data of hematopoietic cells and characteristics of BM physiology, we constructed a tissue cylinder solely occupied by granulocytic progenitors (the most metabolically active stage of the most abundant cell type) to provide a physiologically relevant limiting case. Although the number of possible cellular architectures is large, all simulated pO(2) profiles fall between two extreme cases: those of homogeneous tissues with adipocytes and granulocytic progenitors, respectively. This was illustrated by results obtained from a parametric criterion derived for pO(2) depletion in the extravascular tissue. Modeling results suggest that stem and progenitor cells experience a low pO(2) environment in the BMHC. PMID:11463616

  4. 40 CFR 721.9675 - Titanate [Ti6O13 (2-)], di-po-tas-sium.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Titanate , di-po-tas-sium. 721.9675 Section 721.9675 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES... Substances § 721.9675 Titanate , di-po-tas-sium. (a) Chemical substance and significant new uses subject...

  5. 40 CFR 721.9675 - Titanate [Ti6O13 (2-)], di-po-tas-sium.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Titanate , di-po-tas-sium. 721.9675 Section 721.9675 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES... Substances § 721.9675 Titanate , di-po-tas-sium. (a) Chemical substance and significant new uses subject...

  6. Magnetic properties of Li(MnyFe1-y)PO4 and its delithiated phases

    NASA Astrophysics Data System (ADS)

    Yamada, Atsuo; Takei, Yuki; Koizumi, Hiroshi; Sonoyama, Noriyuki; Kanno, Ryoji

    2005-12-01

    A series of synthetic (MnyFe1-y)PO4 (y<0.8) phases with negligible disorder and impurities were obtained by chemical oxidation of crystallized isotypic Li(MnyFe1-y)PO4 under optimized conditions. This enabled us to perform the comparative magnetic study along the two solid-solution lines based on inherent susceptibility data with no parasitic magnetic signals. All samples exhibit antiferromagnetism but the decrease in Néel temperature is more than seven times larger in (MnyFe1-y)PO4 than in Li(MnyFe1-y)PO4. This was discussed in terms of the asymmetric superexchange interaction by an unusual synergetic effect of Jahn-Teller distortion and edge-shared interconnection with PO4 tetrahedra.

  7. Crystallization-Dependent Luminescence Properties of Ce:LuPO4.

    PubMed

    Sun, Congting; Li, Xingxing; Wang, Hao; Xue, Dongfeng

    2016-03-21

    The luminescence properties of Ce:LuPO4 depend on both the Ce(3+) center and the host lattice. In this article, we studied the dependence of the luminescence properties of Ce:LuPO4 on both the doping concentration of Ce(3+) and the size and morphology of the LuPO4 matrix at micro- and nanosize regimes. The crystalline behavior of Ce:LuPO4, including its size and shape, was investigated via precursor transformation crystallization. On the basis of this crystallization approach, Ce:LuPO4 hollow nanospheres, nanorods, and regular tetrahedrons were obtained. For micro- and nanostructured Ce:LuPO4, the surface-induced chemical bonding architecture can be effectively varied by controlling the size of the crystalline material and its geometry. Our experimental observations demonstrate that one-dimensional Ce:LuPO4 nanorods doped with 0.1 mol % Ce(3+) possess the best performance among the as-prepared samples. The significant anisotropy of Ce:LuPO4 nanorods can result in a larger specific surface area and enhanced luminescence properties. Moreover, the improved luminescence property of Ce:LuPO4 nanostructures can also be optimized by increasing the preferential anisotropic chemical bonding architecture to regulate the 5d level of Ce(3+). Our work also shows that the photoluminescence emission intensity of Ce:LuPO4 nanorods is increased as the surface area normal to their axial direction increases. From the standpoint of crystallization, the luminescence properties of Ce(3+) in nano- and microsize matrixes can be well-optimized by controlling the crystalline behavior of the host lattice under proper synthesis conditions. PMID:26863291

  8. Crystallization-Dependent Luminescence Properties of Ce:LuPO4.

    PubMed

    Sun, Congting; Li, Xingxing; Wang, Hao; Xue, Dongfeng

    2016-03-21

    The luminescence properties of Ce:LuPO4 depend on both the Ce(3+) center and the host lattice. In this article, we studied the dependence of the luminescence properties of Ce:LuPO4 on both the doping concentration of Ce(3+) and the size and morphology of the LuPO4 matrix at micro- and nanosize regimes. The crystalline behavior of Ce:LuPO4, including its size and shape, was investigated via precursor transformation crystallization. On the basis of this crystallization approach, Ce:LuPO4 hollow nanospheres, nanorods, and regular tetrahedrons were obtained. For micro- and nanostructured Ce:LuPO4, the surface-induced chemical bonding architecture can be effectively varied by controlling the size of the crystalline material and its geometry. Our experimental observations demonstrate that one-dimensional Ce:LuPO4 nanorods doped with 0.1 mol % Ce(3+) possess the best performance among the as-prepared samples. The significant anisotropy of Ce:LuPO4 nanorods can result in a larger specific surface area and enhanced luminescence properties. Moreover, the improved luminescence property of Ce:LuPO4 nanostructures can also be optimized by increasing the preferential anisotropic chemical bonding architecture to regulate the 5d level of Ce(3+). Our work also shows that the photoluminescence emission intensity of Ce:LuPO4 nanorods is increased as the surface area normal to their axial direction increases. From the standpoint of crystallization, the luminescence properties of Ce(3+) in nano- and microsize matrixes can be well-optimized by controlling the crystalline behavior of the host lattice under proper synthesis conditions.

  9. Processes controlling the distributions of Cd and PO4 in the ocean

    NASA Astrophysics Data System (ADS)

    Quay, Paul; Cullen, Jay; Landing, William; Morton, Peter

    2015-06-01

    Depth profiles of dissolved Cd and PO4 from a global data compilation were used to derive the Cd/P of particles exported from the surface layer, and the results indicate lowest values in the North Atlantic (0.17 ± 0.05), highest in the Southern (0.56 ± 0.24), and intermediate in the South Indian (0.31 ± 0.14) and North Pacific (0.36 ± 0.08) Ocean basins. The Cd/P of exported particles in high nutrient-low chlorophyll (HNLC) regions is twice that for particles exported in non-HNLC regions as is the fractionation effect during biological uptake of Cd and PO4, and these trends primarily determine the spatial trends of dissolved Cd/PO4 observed in the surface ocean. In deep waters the lowest dissolved Cd/PO4 of 0.23 ± 0.07 is found in the North Atlantic Ocean and the result primarily of low Cd/PO4 of North Atlantic Deep Water (0.23). In contrast, deep waters in the Southern Ocean have significantly higher dissolved Cd/PO4 (0.30 ± 0.06), which is a result of the Cd/PO4 of upwelled deep water from the South Pacific and South Indian (0.28) and the high Cd/P of degrading particles. A multibox model that accounts for the impacts of particle degradation and thermohaline circulation in the deep sea yields dissolved Cd and PO4 interbasin trends close to observations. Model experiments illustrate the dependence of the dissolved Cd/PO4 of the deep sea on the extent of HNLC conditions in the Southern Ocean and the impact on reconstructing paleo PO4 concentrations from a Cd proxy.

  10. Pnicogen bonded complexes of PO2X (X = F, Cl) with nitrogen bases.

    PubMed

    Alkorta, Ibon; Elguero, José; Del Bene, Janet E

    2013-10-10

    An ab initio MP2/aug'-cc-pVTZ study has been carried out on complexes formed between PO2X (X = F and Cl) as the Lewis acids and a series of nitrogen bases ZN, including NH3, H2C═NH, NH2F, NP, NCH, NCF, NF3, and N2. Binding energies of these complexes vary from -10 to -150 kJ/mol, and P-N distances from 1.88 to 2.72 Å. Complexes ZN:PO2F have stronger P(...)N bonds and shorter P-N distances than the corresponding complexes ZN:PO2Cl. Charge transfer from the N lone pair through the π-hole to the P-X and P-O σ* orbitals leads to stabilization of these complexes, although charge-transfer energies can be evaluated only for complexes with binding energies less than -71 kJ/mol. Complexation of PO2X with the strongest bases leads to P···N bonds with a significant degree of covalency, and P-N distances that approach the P-N distances in the molecules PO2NC and PO2NH2. In these complexes, the PO2X molecules distort from planarity. Changes in (31)P absolute chemical shieldings upon complexation do not correlate with changes in charges on P, although they do correlate with the binding energies of the complexes. EOM-CCSD spin-spin coupling constants (1p)J(P-N) are dominated by the Fermi-contact term, which is an excellent approximation to total J. (1p)J(P-N) values are small at long distances, increase as the distance decreases, but then decrease at short P-N distances. At the shortest distances, values of (1p)J(P-N) approach (1)J(P-N) for the molecules PO2NC and PO2NH2.

  11. LiFePO4 Nanostructures Fabricated from Iron(III) Phosphate (FePO4 x 2H2O) by Hydrothermal Method.

    PubMed

    Saji, Viswanathan S; Song, Hyun-Kon

    2015-01-01

    Electrode materials having nanometer scale dimensions are expected to have property enhancements due to enhanced surface area and mass/charge transport kinetics. This is particularly relevant to intrinsically low electronically conductive materials such as lithium iron phosphate (LiFePO4), which is of recent research interest as a high performance intercalation electrode material for Li-ion batteries. Many of the reported works on LiFePO4 synthesis are unattractive either due to the high cost of raw materials or due to the complex synthesis technique. In this direction, synthesis of LiFePO4 directly from inexpensive FePO4 shows promise.The present study reports LiFePO4 nanostructures prepared from iron (III) phosphate (FePO4 x 2H2O) by precipitation-hydrothermal method. The sintered powder was characterized by X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), Inductive coupled plasma-optical emission spectroscopy (ICP-OES), and Electron microscopy (SEM and TEM). Two synthesis methods, viz. bulk synthesis and anodized aluminum oxide (AAO) template-assisted synthesis are reported. By bulk synthesis, micro-sized particles having peculiar surface nanostructuring were formed at precipitation pH of 6.0 to 7.5 whereas typical nanosized LiFePO4 resulted at pH ≥ 8.0. An in-situ precipitation strategy inside the pores of AAO utilizing the spin coating was utilized for the AAO-template-assisted synthesis. The template with pores filled with the precipitate was subsequently subjected to hydrothermal process and high temperature sintering to fabricate compact rod-like structures.

  12. LiFePO4 Nanostructures Fabricated from Iron(III) Phosphate (FePO4 x 2H2O) by Hydrothermal Method.

    PubMed

    Saji, Viswanathan S; Song, Hyun-Kon

    2015-01-01

    Electrode materials having nanometer scale dimensions are expected to have property enhancements due to enhanced surface area and mass/charge transport kinetics. This is particularly relevant to intrinsically low electronically conductive materials such as lithium iron phosphate (LiFePO4), which is of recent research interest as a high performance intercalation electrode material for Li-ion batteries. Many of the reported works on LiFePO4 synthesis are unattractive either due to the high cost of raw materials or due to the complex synthesis technique. In this direction, synthesis of LiFePO4 directly from inexpensive FePO4 shows promise.The present study reports LiFePO4 nanostructures prepared from iron (III) phosphate (FePO4 x 2H2O) by precipitation-hydrothermal method. The sintered powder was characterized by X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), Inductive coupled plasma-optical emission spectroscopy (ICP-OES), and Electron microscopy (SEM and TEM). Two synthesis methods, viz. bulk synthesis and anodized aluminum oxide (AAO) template-assisted synthesis are reported. By bulk synthesis, micro-sized particles having peculiar surface nanostructuring were formed at precipitation pH of 6.0 to 7.5 whereas typical nanosized LiFePO4 resulted at pH ≥ 8.0. An in-situ precipitation strategy inside the pores of AAO utilizing the spin coating was utilized for the AAO-template-assisted synthesis. The template with pores filled with the precipitate was subsequently subjected to hydrothermal process and high temperature sintering to fabricate compact rod-like structures. PMID:26328435

  13. Unusually high (210)Po activities in the surface water of the Zhubi Coral Reef Lagoon in the South China Sea.

    PubMed

    Yang, Weifeng; Huang, Yipu; Chen, Min; Qiu, Yusheng; Li, Hongbin; Zhang, Lei

    2011-10-01

    Recent researches revealed the exciting application of (210)Po in tracing carbon and nitrogen cycling in the coral reef system. In order to quantify the recycling of particulate organic nitrogen (PON), both (210)Po and (210)Pb were examined at both high and low tides in the Zhubi Coral Reef lagoon, the South China Sea. Unusually, much higher (210)Po activities and (210)Po/(210)Pb ratios, in comparison with those found in the open seawater and the lagoon subsurface water, showed additional input of (210)Po besides production from in situ(210)Pb in the lagoon surface water. Statistical analysis identified that the reef flat seawater was the additional (210)Po source. Based on a mass balance model, the input rates of (210)Po varied from 0.04 Bq m(-3)year(-1) to 8.41 Bq m(-3)year(-1). On average, the additional (210)Po contributed more than 60% of the total (210)Po. The particulate (210)Po significantly correlated with the concentrations of PON, indicating that diffusion of (210)Po from sediment could be used to quantify the recycling of nitrogen. The average input rate of nitrogen was 16 mmol m(-3)year(-1), which can support up to 11% of the primary production rate. These results suggested that the unusual behavior of (210)Po could provide new insight into the nitrogen recycling in the coral reef system.

  14. Room-temperature miscibility gap in LixFePO4.

    PubMed

    Yamada, Atsuo; Koizumi, Hiroshi; Nishimura, Shin-Ichi; Sonoyama, Noriyuki; Kanno, Ryoji; Yonemura, Masao; Nakamura, Tatsuya; Kobayashi, Yo

    2006-05-01

    The rechargeable lithium-ion cell is an advanced energy-storage system. However, high cost, safety hazards, and chemical instability prohibit its use in large-scale applications. An alternative cathode material, LiFePO(4), solves these problems, but has a kinetic problem involving strong electron/hole localization. One reason for this is believed to be the limited carrier density in the fixed monovalent Fe(3+)PO(4)/LiFe(2+)PO(4) two-phase electrode reaction in LixFePO4. Here, we provide experimental evidence that LixFePO4, at room temperature, can be described as a mixture of the Fe(3+)/Fe(2+) mixed-valent intermediate LialphaFePO4 and Li1-betaFePO4 phases. Using powder neutron diffraction, the site occupancy numbers for lithium in each phase were refined to be alpha=0.05 and 1-beta=0.89. The corresponding solid solution ranges outside the miscibility gap (0

  15. Use of moss and lichen species to identify (210)Po-contaminated regions.

    PubMed

    Długosz-Lisiecka, Magdalena; Wróbel, Justyna

    2014-12-01

    (210)Po concentration in urban air fluctuates as a result of natural (222)Rn radionuclide exhalation and technical activity that is especially linked with high-temperature processes. Each year, an average 11 GBq of (210)Po is released from local power plants into urban air. Over two months, about 180 samples in central Poland were collected. To detect the concentration of (210)Po activity, two common species of biomonitors were chosen: the moss Pleurozium schreberi and the lichen Hypogymnia physodes. For the same locale, (210)Po in lichen shows an average of twice the amount of activity concentration than the moss. In moss, (210)Po concentrations in Lodz ranged from 41.5 Bq kg(-1) to 258.0 Bq kg(-1), while in lichen it ranges from 74.2 Bq kg(-1) to 670.9 Bq kg(-1). On the basis of the measured activity of (210)Po maps, radionuclide distribution has been prepared. For areas identified with higher concentrations of (210)Po, Quantum Gis has been applied.

  16. Annual dose of Taiwanese from the ingestion of 210Po in oysters.

    PubMed

    Lee, Hsiu-wei; Wang, Jeng-Jong

    2013-03-01

    Oysters around the coast of Taiwan were collected, dried, spiked with a (209)Po tracer for yield, digested with concentrated HNO(3) and H(2)O(2), and finally dissolved in 0.5 N HCl. The polonium was then spontaneously deposited onto a silver disc, and the activity of (210)Po was measured using an alpha spectrum analyzer equipped with a silicon barrier detector. Meanwhile, the internal effective dose of (210)Po coming from the intake of oysters by Taiwanese was evaluated. The results of the present study indicate that (210)Po average activity concentrations ranged from 23.4 ± 0.4 to 126 ± 94 Bq kg(-1) of fresh oysters. The oysters coming from Penghu island and Kinmen island regions contain higher concentrations of (210)Po in comparison with oysters from other regions of Taiwan. The value of (210)Po weighted average activity concentrations for all oyster samples studied is 25.9 Bq kg(-1). The annual effective dose of Taiwanese due to the ingestion of (210)Po in oysters was estimated to be 4.1 × 10(-2) mSv y(-1).

  17. High efficient multifunctional Ag3PO4 loaded hydroxyapatite nanowires for water treatment.

    PubMed

    Li, Yaling; Zhou, Hangyu; Zhu, Genxing; Shao, Changyu; Pan, Haihua; Xu, Xurong; Tang, Ruikang

    2015-12-15

    Organic, inorganic, and biological pollutants are typical water contaminants and they seriously affect water quality. In this study, we suggested that a novel multifunctional Ag3PO4 loaded hydroxyapatite (HAP) material can remove the typical pollutants from water. The Ag3PO4/HAP composites were synthesized facilely via in-situ precipitation of Ag3PO4 on the pre-existing HAP nanowires. By optimizing the composition of Ag3PO4 and HAP, the material could achieve an optimal photocatalytic activity to decompose rhodamine B (RhB), methyl orange (MO) and methylene blue (MB) under visible light irradiations with enhanced pH stability. Besides, the adsorption of Pb(II) on the Ag3PO4/HAP reached a maximum capacity of 250 mg/g and this value was approximately three times as that of pure HAP. Furthermore, the composite material exhibited excellent antibacterial activities towards gram-negative bacterium (Escherichia coli) and gram-positive bacterium (Stphylococcus aureus). The results highlighted the cooperative effect between Ag3PO4 and hydroxyapatite (HAP). The simultaneous removals of dyes, toxic metal ions, and bacteria with a high efficiency followed an easy approach for the purification of contaminated water via the rationally designed material, in which the Ag3PO4/HAP composite might be developed as a general water treatment material with multiple functions. PMID:26150280

  18. Unlocking the energy capabilities of micron-sized LiFePO4

    NASA Astrophysics Data System (ADS)

    Guo, Limin; Zhang, Yelong; Wang, Jiawei; Ma, Lipo; Ma, Shunchao; Zhang, Yantao; Wang, Erkang; Bi, Yujing; Wang, Deyu; McKee, William C.; Xu, Ye; Chen, Jitao; Zhang, Qinghua; Nan, Cewen; Gu, Lin; Bruce, Peter G.; Peng, Zhangquan

    2015-08-01

    Utilization of LiFePO4 as a cathode material for Li-ion batteries often requires size nanonization coupled with calcination-based carbon coating to improve its electrochemical performance, which, however, is usually at the expense of tap density and may be environmentally problematic. Here we report the utilization of micron-sized LiFePO4, which has a higher tap density than its nano-sized siblings, by forming a conducting polymer coating on its surface with a greener diazonium chemistry. Specifically, micron-sized LiFePO4 particles have been uniformly coated with a thin polyphenylene film via the spontaneous reaction between LiFePO4 and an aromatic diazonium salt of benzenediazonium tetrafluoroborate. The coated micron-sized LiFePO4, compared with its pristine counterpart, has shown improved electrical conductivity, high rate capability and excellent cyclability when used as a `carbon additive free' cathode material for rechargeable Li-ion batteries. The bonding mechanism of polyphenylene to LiFePO4/FePO4 has been understood with density functional theory calculations.

  19. On a framework for generating PoD curves assisted by numerical simulations

    NASA Astrophysics Data System (ADS)

    Subair, S. Mohamed; Agrawal, Shweta; Balasubramaniam, Krishnan; Rajagopal, Prabhu; Kumar, Anish; Rao, Purnachandra B.; Tamanna, Jayakumar

    2015-03-01

    The Probability of Detection (PoD) curve method has emerged as an important tool for the assessment of the performance of NDE techniques, a topic of particular interest to the nuclear industry where inspection qualification is very important. The conventional experimental means of generating PoD curves though, can be expensive, requiring large data sets (covering defects and test conditions), and equipment and operator time. Several methods of achieving faster estimates for PoD curves using physics-based modelling have been developed to address this problem. Numerical modelling techniques are also attractive, especially given the ever-increasing computational power available to scientists today. Here we develop procedures for obtaining PoD curves, assisted by numerical simulation and based on Bayesian statistics. Numerical simulations are performed using Finite Element analysis for factors that are assumed to be independent, random and normally distributed. PoD curves so generated are compared with experiments on austenitic stainless steel (SS) plates with artificially created notches. We examine issues affecting the PoD curve generation process including codes, standards, distribution of defect parameters and the choice of the noise threshold. We also study the assumption of normal distribution for signal response parameters and consider strategies for dealing with data that may be more complex or sparse to justify this. These topics are addressed and illustrated through the example case of generation of PoD curves for pulse-echo ultrasonic inspection of vertical surface-breaking cracks in SS plates.

  20. Use of moss and lichen species to identify (210)Po-contaminated regions.

    PubMed

    Długosz-Lisiecka, Magdalena; Wróbel, Justyna

    2014-12-01

    (210)Po concentration in urban air fluctuates as a result of natural (222)Rn radionuclide exhalation and technical activity that is especially linked with high-temperature processes. Each year, an average 11 GBq of (210)Po is released from local power plants into urban air. Over two months, about 180 samples in central Poland were collected. To detect the concentration of (210)Po activity, two common species of biomonitors were chosen: the moss Pleurozium schreberi and the lichen Hypogymnia physodes. For the same locale, (210)Po in lichen shows an average of twice the amount of activity concentration than the moss. In moss, (210)Po concentrations in Lodz ranged from 41.5 Bq kg(-1) to 258.0 Bq kg(-1), while in lichen it ranges from 74.2 Bq kg(-1) to 670.9 Bq kg(-1). On the basis of the measured activity of (210)Po maps, radionuclide distribution has been prepared. For areas identified with higher concentrations of (210)Po, Quantum Gis has been applied. PMID:25301434

  1. Unlocking the energy capabilities of micron-sized LiFePO4

    PubMed Central

    Guo, Limin; Zhang, Yelong; Wang, Jiawei; Ma, Lipo; Ma, Shunchao; Zhang, Yantao; Wang, Erkang; Bi, Yujing; Wang, Deyu; McKee, William C.; Xu, Ye; Chen, Jitao; Zhang, Qinghua; Nan, Cewen; Gu, Lin; Bruce, Peter G.; Peng, Zhangquan

    2015-01-01

    Utilization of LiFePO4 as a cathode material for Li-ion batteries often requires size nanonization coupled with calcination-based carbon coating to improve its electrochemical performance, which, however, is usually at the expense of tap density and may be environmentally problematic. Here we report the utilization of micron-sized LiFePO4, which has a higher tap density than its nano-sized siblings, by forming a conducting polymer coating on its surface with a greener diazonium chemistry. Specifically, micron-sized LiFePO4 particles have been uniformly coated with a thin polyphenylene film via the spontaneous reaction between LiFePO4 and an aromatic diazonium salt of benzenediazonium tetrafluoroborate. The coated micron-sized LiFePO4, compared with its pristine counterpart, has shown improved electrical conductivity, high rate capability and excellent cyclability when used as a ‘carbon additive free' cathode material for rechargeable Li-ion batteries. The bonding mechanism of polyphenylene to LiFePO4/FePO4 has been understood with density functional theory calculations. PMID:26235395

  2. Visible light assisted degradation of organic dye using Ag{sub 3}PO{sub 4}

    SciTech Connect

    Dhanabal, R.; Bose, A. Chandra; Velmathi, S.

    2015-06-24

    The study of visible light photodegradation of organic dye Methylene Blue (MB) have been investigated using silver phosphate (Ag{sub 3}PO{sub 4}) as a photocatalyst which is good efficient material for photocatalytic reaction. The simple ion-exchange method is used to prepare Ag{sub 3}PO{sub 4}. The structure of the material have been confirmed using X-ray diffraction which shows cubic structure of Ag{sub 3}PO{sub 4}. The functional group of the Ag{sub 3}PO{sub 4} has been verified by Fourier transform infrared spectroscopy. The bandgap of Ag{sub 3}PO{sub 4} is calculated using kubelka-munk function from the ultra violet-visible diffuse reflectance spectroscopy, the absorption of Ag{sub 3}PO{sub 4} starts from 470 nm. Under simulated visible light irradiation, Ag{sub 3}PO{sub 4} catalyst exhibits good catalytic ability for degrading MB dye.

  3. Room-temperature miscibility gap in LixFePO4

    NASA Astrophysics Data System (ADS)

    Yamada, Atsuo; Koizumi, Hiroshi; Nishimura, Shin-Ichi; Sonoyama, Noriyuki; Kanno, Ryoji; Yonemura, Masao; Nakamura, Tatsuya; Kobayashi, Yo

    2006-05-01

    The rechargeable lithium-ion cell is an advanced energy-storage system. However, high cost, safety hazards, and chemical instability prohibit its use in large-scale applications. An alternative cathode material, LiFePO4, solves these problems, but has a kinetic problem involving strong electron/hole localization. One reason for this is believed to be the limited carrier density in the fixed monovalent Fe3+PO4/LiFe2+PO4 two-phase electrode reaction in LixFePO4. Here, we provide experimental evidence that LixFePO4, at room temperature, can be described as a mixture of the Fe3+/Fe2+ mixed-valent intermediate LiαFePO4 and Li1-βFePO4 phases. Using powder neutron diffraction, the site occupancy numbers for lithium in each phase were refined to be α=0.05 and 1-β=0.89. The corresponding solid solution ranges outside the miscibility gap (0

  4. Room-temperature miscibility gap in LixFePO4.

    PubMed

    Yamada, Atsuo; Koizumi, Hiroshi; Nishimura, Shin-Ichi; Sonoyama, Noriyuki; Kanno, Ryoji; Yonemura, Masao; Nakamura, Tatsuya; Kobayashi, Yo

    2006-05-01

    The rechargeable lithium-ion cell is an advanced energy-storage system. However, high cost, safety hazards, and chemical instability prohibit its use in large-scale applications. An alternative cathode material, LiFePO(4), solves these problems, but has a kinetic problem involving strong electron/hole localization. One reason for this is believed to be the limited carrier density in the fixed monovalent Fe(3+)PO(4)/LiFe(2+)PO(4) two-phase electrode reaction in LixFePO4. Here, we provide experimental evidence that LixFePO4, at room temperature, can be described as a mixture of the Fe(3+)/Fe(2+) mixed-valent intermediate LialphaFePO4 and Li1-betaFePO4 phases. Using powder neutron diffraction, the site occupancy numbers for lithium in each phase were refined to be alpha=0.05 and 1-beta=0.89. The corresponding solid solution ranges outside the miscibility gap (0

  5. Electrochemical performance of Sol-Gel synthesized LiFePO{sub 4} in lithium batteries

    SciTech Connect

    Hu, Yaoqin; Doeff, Marca M.; Kostecki, Robert; Finones, Rita

    2003-06-16

    LiFePO{sub 4}, Li{sub 0.98}Mg{sub 0.01}FePO{sub 4}, and Li{sub 0.96}Ti{sub 0.01}FePO{sub 4} were synthesized via a sol-gel method, using a variety of processing conditions. For comparison, LiFePO{sub 4} was also synthesized from iron acetate by a solid state method. The electrochemical performance of these materials in lithium cells was evaluated and correlated to mean primary particle size and residual carbon structure in the LiFePO{sub 4} samples, as determined by Raman microprobe spectroscopy. For materials with mean agglomerate sizes below 20 {micro}m, an association between structure and crystallinity of the residual carbon and improved utilization was observed. Addition of small amounts of organic compounds or polymers during processing results in carbon coatings with higher graphitization ratios and better electronic properties on the LiFePO{sub 4} samples and improves cell performance in some cases, even though total carbon contents remain very low (<2%). In contrast, no performance enhancement was seen for samples doped with Mg or Ti. These results suggest that it should be possible to design high power LiFePO{sub 4} electrodes without unduly compromising energy density by optimizing the carbon coating on the particles.

  6. Unlocking the energy capabilities of micron-sized LiFePO4.

    PubMed

    Guo, Limin; Zhang, Yelong; Wang, Jiawei; Ma, Lipo; Ma, Shunchao; Zhang, Yantao; Wang, Erkang; Bi, Yujing; Wang, Deyu; McKee, William C; Xu, Ye; Chen, Jitao; Zhang, Qinghua; Nan, Cewen; Gu, Lin; Bruce, Peter G; Peng, Zhangquan

    2015-08-03

    Utilization of LiFePO4 as a cathode material for Li-ion batteries often requires size nanonization coupled with calcination-based carbon coating to improve its electrochemical performance, which, however, is usually at the expense of tap density and may be environmentally problematic. Here we report the utilization of micron-sized LiFePO4, which has a higher tap density than its nano-sized siblings, by forming a conducting polymer coating on its surface with a greener diazonium chemistry. Specifically, micron-sized LiFePO4 particles have been uniformly coated with a thin polyphenylene film via the spontaneous reaction between LiFePO4 and an aromatic diazonium salt of benzenediazonium tetrafluoroborate. The coated micron-sized LiFePO4, compared with its pristine counterpart, has shown improved electrical conductivity, high rate capability and excellent cyclability when used as a 'carbon additive free' cathode material for rechargeable Li-ion batteries. The bonding mechanism of polyphenylene to LiFePO4/FePO4 has been understood with density functional theory calculations.

  7. Hollow GdPO4:Eu3+ microspheres: Luminescent properties and applications as drug carrier

    NASA Astrophysics Data System (ADS)

    Tang, Yanxia; Mei, Rui; Yang, Shaokun; Tang, Hongxia; Yin, Wenzhong; Xu, Yongchun; Gao, Yaping

    2016-04-01

    GdPO4:Eu3+ samples were synthesized by a hydrothermal process using melamine formaldehyde (MF) as template. The X-ray diffraction (XRD) patterns and the Fourier Transform Infrared (FTIR) spectrum suggested that GdPO4:Eu3+ has a hexagonal phase. The scanning electron microscope (SEM) and transmission electron microscope (TEM) images showed that the obtained GdPO4:Eu3+ are hollow microspheres with diameters in the range of 1-1.5 μm. Under the excitation at 245 nm, hexagonal GdPO4:Eu3+ hollow microspheres showed emission bands originating from the 5D0 → 7FJ (J = 1, 2, 3 and 4) transitions of Eu3+. The drug release properties of hexagonal GdPO4:Eu3+ hollow microspheres were exhibited by the doxorubicin hydrochloride (DOX) release test. The biocompatibility of hexagonal GdPO4:Eu3+ hollow microsphere was tested by the standard 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The results indicated that hollow GdPO4:Eu3+ microspheres have potential applications in biomedicine fields.

  8. On a framework for generating PoD curves assisted by numerical simulations

    SciTech Connect

    Subair, S. Mohamed Agrawal, Shweta Balasubramaniam, Krishnan Rajagopal, Prabhu; Kumar, Anish; Rao, Purnachandra B.; Tamanna, Jayakumar

    2015-03-31

    The Probability of Detection (PoD) curve method has emerged as an important tool for the assessment of the performance of NDE techniques, a topic of particular interest to the nuclear industry where inspection qualification is very important. The conventional experimental means of generating PoD curves though, can be expensive, requiring large data sets (covering defects and test conditions), and equipment and operator time. Several methods of achieving faster estimates for PoD curves using physics-based modelling have been developed to address this problem. Numerical modelling techniques are also attractive, especially given the ever-increasing computational power available to scientists today. Here we develop procedures for obtaining PoD curves, assisted by numerical simulation and based on Bayesian statistics. Numerical simulations are performed using Finite Element analysis for factors that are assumed to be independent, random and normally distributed. PoD curves so generated are compared with experiments on austenitic stainless steel (SS) plates with artificially created notches. We examine issues affecting the PoD curve generation process including codes, standards, distribution of defect parameters and the choice of the noise threshold. We also study the assumption of normal distribution for signal response parameters and consider strategies for dealing with data that may be more complex or sparse to justify this. These topics are addressed and illustrated through the example case of generation of PoD curves for pulse-echo ultrasonic inspection of vertical surface-breaking cracks in SS plates.

  9. Estimating benthic fluxes of trace elements to hypoxic coastal waters using 210Po

    NASA Astrophysics Data System (ADS)

    Kim, Tae-Hoon; Kim, Guebuem

    2014-12-01

    The activities of colloidal (10 kDa-0.45 μm) and truly dissolved (<10 kDa) 210Po and 210Pb, dissolved inorganic nutrients, and trace elements (Al, V, Co, Ni, Cu, Mo, Mn, and Fe) were measured in the artificial and saline Lake Shihwa, South Korea in July 2011. The boundary between oxic and hypoxic layers, indexed by NH4+, Mn, and dissolved oxygen, was determined by the pycnocline formed at the depth of 2-4 m. The total activities of 210Po and 210Pb in Lake Shihwa were in the range of 10.5-20.4 dpm 100 L-1 and 6.4 to 9.8 dpm 100 L-1, respectively. The proportions of the truly dissolved, colloidal, and particulate phases were, respectively, 55 ± 6%, 29 ± 5%, and 16 ± 3% for 210Po, and 48 ± 6%, 29 ± 7%, and 23 ± 4% for 210Pb. The activities of 210Po were 20-55% higher than those of 210Pb. The benthic flux of 210Po is determined on the basis of the 210Po mass balance model in the water column. Since the excess activities of dissolved 210Po relative to 210Pb showed a positive correlation with the concentrations of trace elements (except for Al), the benthic fluxes of the trace elements from bottom sediment were successfully calculated using these relationships and the 210Po fluxes. Our study highlights that 210Po can be used as a powerful tracer for estimating trace element fluxes from bottom sediment in a hypoxic environment.

  10. 210Po in the marine environment with emphasis on its behaviour within the biosphere.

    PubMed

    Fowler, Scott W

    2011-05-01

    The distribution and behaviour of the natural-series alpha-emitter polonium-210 in the marine environment has been under study for many years primarily due to its enhanced bioaccumulation, its strong affinity for binding with certain internal tissues, and its importance as a contributor to the natural radiation dose received by marine biota as well as humans consuming seafoods. Results from studies spanning nearly 5 decades show that (210)Po concentrations in organisms vary widely among the different phylogenic groups as well as between the different tissues of a given species. Such variation results in (210)Po concentration factors ranging from approximately 10(3) to over 10(6) depending upon the organism or tissue considered. (210)Po/(210)Pb ratios in marine species are generally greater than unity and tend to increase up the food chain indicating that (210)Po is preferentially taken up by organisms compared to its progenitor (210)Pb. The effective transfer of (210)Po up the food chain is primarily due to the high degree of assimilation of the radionuclide from ingested food and its subsequent strong retention in the organisms. In some cases this mechanism may lead to an apparent biomagnification of (210)Po at the higher trophic level. Various pelagic species release (210)Po and (210)Pb packaged in organic biodetrital particles that sink and remove these radionuclides from the upper water column, a biogeochemical process which, coupled with scavenging rates of this radionuclide pair, is being examined as a possible proxy for estimating downward organic carbon fluxes in the sea. Data related to preferential bioaccumulation in various organisms, their tissues, resultant radiation doses to these species, and the processes by which (210)Po is transferred and recycled through the food web are discussed. In addition, the main gaps in our present knowledge and proposed areas for future studies on the biogeochemical behaviour of (210)Po and its use as a tracer of

  11. Contribution of plated-out 218Po and 214Po to measurements of airborne 222Rn and daughters with plastic (CR-39) nuclear track detectors

    NASA Astrophysics Data System (ADS)

    Kahn, Bernd; Wang, Zuoyuan; Sensistaffar, Edwin

    1984-01-01

    The fraction of alpha-particle tracks due to radioactivity plated out on its surface was measured for CR-39 nuclear track detector foils used to determine working level values in air. Bare foils were exposed to known concentrations of airborne 222Rn and its short-lived daughters in a calibration chamber. The amounts of 218Po and 214Po on the foil surface were measured with a calibrated diffused junction detector-spectrometer system immediately after the foils were removed from the chamber. Deposition was mostly by 218Po, with some 214Pb but essentially no 214Bi. The track density due to the plated-out radionuclides and the 222Rn, 218Po, and 214Po in chamber air was calculated and compared to the value measured by electrochemical etching. The calculated values generally were slightly above the measured values. On the basis of these calculations, the deposited radioactivity contributed slightly less than one-half of the total tracks in one test and slightly more than two-thirds in another. This effect complicates calibration of the detector relative to airborne radon daughters.

  12. An experimental analysis of the contribution of 210Po and of 210Po produced by 210Pb decay to the gross alpha-particle activity of water samples.

    PubMed

    Arndt, Michael F; West, Lynn E

    2008-09-01

    The contribution of 210Po and of 210Po produced by 210Pb decay to the gross alpha-particle activity of water samples by U.S. Environmental Protection Agency Method 900.0 is investigated as a function of residue mass and geometry and time between sample collection and analysis. It is shown that these factors can cause the contribution to gross alpha-particle activity of 210Po to be up to 2.0 and 1.1 times the initial 210Po activity for grab and quarterly composite samples, respectively, and can cause the contribution to gross alpha-particle activity of 210Po from 210Pb decay to be up to 1.1 times and 1.5 times the 210Pb activity for grab and quarterly composite samples, respectively. It is also shown qualitatively that at least for some residues, there is a loss of polonium due to volatilization when the sample is heated over a flame.

  13. Identifying the Structure of the Intermediate, Li2/3CoPO4, Formed during Electrochemical Cycling of LiCoPO4

    PubMed Central

    2014-01-01

    In situ synchrotron diffraction measurements and subsequent Rietveld refinements are used to show that the high energy density cathode material LiCoPO4 (space group Pnma) undergoes two distinct two-phase reactions upon charge and discharge, both occurring via an intermediate Li2/3(Co2+)2/3(Co3+)1/3PO4 phase. Two resonances are observed for Li2/3CoPO4 with intensity ratios of 2:1 and 1:1 in the 31P and 7Li NMR spectra, respectively. An ordering of Co2+/Co3+ oxidation states is proposed within a (a × 3b × c) supercell, and Li+/vacancy ordering is investigated using experimental NMR data in combination with first-principles solid-state DFT calculations. In the lowest energy configuration, both the Co3+ ions and Li vacancies are found to order along the b-axis. Two other low energy Li+/vacancy ordering schemes are found only 5 meV per formula unit higher in energy. All three configurations lie below the LiCoPO4–CoPO4 convex hull and they may be readily interconverted by Li+ hops along the b-direction. PMID:25960604

  14. Effect of the synthesis conditions on the electrochemical properties of LiFePO{sub 4} obtained from NH{sub 4}FePO{sub 4}

    SciTech Connect

    Prosini, Pier Paolo Gislon, Paola; Cento, Cinzia; Carewska, Maria; Masci, Amedeo

    2013-09-01

    Graphical abstract: - Highlights: • Four different samples of FAP were synthesized by precipitation techniques. • The samples were used as precursors to synthesize electrochemical active LiFePO{sub 4}. • Their morphology, composition, structure and electrochemical performance were studied. • The LiFePO{sub 4} electrochemical performance resulted affected by the preparation method - Abstract: In this paper the morphological, structural and electrochemical properties of crystalline lithium iron phosphate (LiFePO{sub 4}) obtained from ferrous ammonium phosphate (FAP) have been studied. The FAP was obtained following four different processes, namely: (1) homogeneous phase precipitation, (2) heterogeneous phase precipitation from stoichiometric sodium phosphate, (3) heterogeneous phase precipitation from stoichiometric ammonium phosphate, and (4) heterogeneous phase precipitation from over stoichiometric ammonium phosphate. Lithium iron phosphate was prepared by solid state reaction of FAP with lithium hydroxide. In order to evaluate the effect of reaction time and synthesis temperature the LiFePO{sub 4} was prepared varying the heating temperatures (550, 600 and 700 °C) and the reaction times (1 or 2 h). The morphology of the materials was evaluated by scanning electron microscopy while the chemical composition was determined by electron energy loss spectroscopy. X-ray diffraction was used to evaluate phase composition, crystal structure and crystallite size. The so obtained LiFePO{sub 4}'s were fully electrochemical characterized and a correlation was found between the crystal size and the electrochemical performance.

  15. Study of phase relationships in the Sr{sub 3}(PO{sub 4}){sub 2}–CePO{sub 4} system. Phase diagram and thermal characteristics of phases

    SciTech Connect

    Matraszek, Aleksandra

    2013-07-15

    A diagram representing phase relationships in the Sr{sub 3}(PO{sub 4}){sub 2}–CePO{sub 4} phosphate system has been developed on the basis of results obtained by thermal analysis (DTA/DSC/TGA) and X-ray diffraction (XRD) methods. One intermediate compound with the formula Sr{sub 3}Ce(PO{sub 4}){sub 3} occurs in the Sr{sub 3}(PO{sub 4}){sub 2}–CePO{sub 4} system at temperatures exceeding 1045 °C. The compound has a eulytite structure with the following structural parameters: a=b=c=10.1655(8) Å, α=β=γ=90.00°, V=1050.46(6) Å{sup 3}. It's melting point exceeds 1950 °C. A limited solid solution exists in the system, which possesses the structure of a low-temperature form of Sr{sub 3}(PO{sub 4}){sub 2}. At 1000 °C the maximal concentration of CePO{sub 4} in the solid solution is below 20 mol%. The solid solution phase field narrows with increased temperature. There is a eutectic point in the (Sr{sub 3}(PO{sub 4}){sub 2}+Sr{sub 3}Ce(PO{sub 4}){sub 3}) phase field at 1765 °C and 15 mol% of CePO{sub 4}. The melting temperature of Sr{sub 3}(PO{sub 4}){sub 2} is 1882±15 °C. - Graphical abstract: The phase diagram of Sr{sub 3}(PO{sub 4}){sub 2}–CePO{sub 4} system showing the stability ranges of limited solid solution and Sr{sub 3}Ce(PO{sub 4}){sub 3} phases. - Highlights: • Sr{sub 3}(PO{sub 4}){sub 2} melts at 1882 °C. • Phase diagram of Sr{sub 3}(PO{sub 4}){sub 2}–CePO{sub 4} system has been proposed. • Limited solid solution of CePO{sub 4} in Sr{sub 3}(PO{sub 4}){sub 2} forms in the system. • The Sr{sub 3}Ce(PO{sub 4}){sub 2} phosphate is stable at temperatures above 1045 °C.

  16. Redetermination of β-Ba(PO3)2

    PubMed Central

    Weil, Matthias

    2014-01-01

    In comparison with the previous structure determination of the β-modification of barium catena-polyphosphate that was based on Weissenberg film data [Grenier et al. (1967 ▶). Bull. Soc. Fr. Minéral. Cristallogr. 90, 24–31], the current CCD-data-based redetermination reveals all atoms with anisotropic displacement parameters, standard uncertainties for the atomic coordinates, and the determination of the absolute structure. Moreover, a much higher accuracy in terms of the bond-length distribution for the polyphosphate chain, with two shorter and two longer P—O distances, was achieved. The structure consists of polyphosphate chains extending parallel to [100] with a periodicity of two PO4 tetra­hedra. The Ba2+ cations are located between the chains and are surrounded by ten O atoms in the form of a distorted coordination polyhedron, with Ba—O distances ranging from 2.765 (3) to 3.143 (3) Å, also reflecting the higher precision of the current redetermination. PMID:24764803

  17. New Media E/PO: Building a Digital Astronomy Community

    NASA Astrophysics Data System (ADS)

    Gay, Pamela L.

    2008-05-01

    Today's communications landscape is rich with new technologies. Cell phones and laptops are the constant companions of content consumers, and as we plan tomorrow's Education and Public Outreach programs, we need to consider how to most effectively utilize these technologies with their new, dynamic content possibilities - We need to use New Media. The field of New Media includes dynamic content sites such as: blogs, pod/vodcasts, Flickr, Facebook, Ustream, Twitter, and Second Life. The first part of this talk will summarize what New Media is available in the field of astronomy. All new media technologies have one thing in common: Users can easily create and input their own content and/or comments. These new media users and content contributors can just as easily be professional researchers, E/PO professionals, amateur astronomers, stay-at-home parents, and school kids. All are welcome in the online community, and today, all voices are digitally joined in the cacophony of astronomy new media content. This rich diversity supports many opportunities for learning, mentoring, content distribution, and discussion of ideas (including the debunking of bad ideas). In the second half of this talk, ways to use new media to build a community that shares, promotes, and comments on content is discussed, and techniques for dealing with the high flux of content are outlined. Also covered are the considerations that need to be made to make content as broadly accessible as possible.

  18. EduBites: Cliffs Notes for E/PO

    NASA Astrophysics Data System (ADS)

    Brinkworth, Carolyn; Bartolone, L.; Wenger, M.; Martin, A.; Nichols-Yehling, M.; Hurt, R. L.; Squires, G. K.

    2013-01-01

    We present a new resource for the astronomy education community, with the goal of improving our community’s knowledge and understanding of the educational research papers relevant to our work. EduBites is a searchable database of summaries of peer-reviewed education papers, written by astronomy educators and posted for the entire community to use. While we are all aware that we should be basing our E/PO work on a solid research foundation, many people in the community are pushed for time when it comes to staying on top of the educational literature. EduBites aims to reduce that workload for the benefit of the entire community. Our database is small, but growing, and will ultimately tackle papers across the whole of the astronomy education spectrum, including formal and informal education, outreach, grades K-16, pedagogy, evaluation, and many other topics. We are keen to hear from anyone on the community who would be interested in joining our review team, and welcome feedback on the EduBites user experience.

  19. Midwives in China: 'jie sheng po' to 'zhu chan shi'.

    PubMed

    Harris, Amanda; Belton, Suzanne; Barclay, Lesley; Fenwick, Jenny

    2009-04-01

    We explore the position of midwifery in contemporary China, and draw on fieldwork conducted in Shanxi and Sichuan Provinces during 2005 and 2006, the available literature in English and to a lesser extent in Mandarin. We also explore the historical antecedents to the present-day professional status, practices and position within the health-care system of midwifery in China. We consider the effect on midwifery of the place of biomedicine in the modernising project of the post-reform State, the shift of birth from the private to the public domain, the rise of the medical profession, the medicalisation of birth and the increasing use of technology, and trace changes in the nature of relations between midwives, doctors and the State from Imperial China to the present day. In particular, we examine the changes that have occurred as midwifery has moved from the arena of the lay practitioner ('jie sheng po') to the professional ('zhu chan shi'). We draw out and critique some ways that midwives act to differentiate themselves and lay claim to a variant body of practice-based knowledge, yet question the capacity of midwifery in China today to assert, in any substantial way, a professional identity that distinguishes it from medical obstetric practice.

  20. Po-210 and Pb-210 in water and fish from Taboshar uranium mining Pit Lake, Tajikistan.

    PubMed

    Skipperud, L; Jørgensen, A G; Heier, L S; Salbu, B; Rosseland, B O

    2013-09-01

    Polonium-210 in water and (210)Pb and (210)Po in different fish organs from 3 different fish species in Taboshar Pit Lake (n = 13), located in the uranium mining area in Tajikistan, and in Kairakkum Reservoir (reference lake, n = 3), have been determined as part of a Joint project between Norway, Kazakhstan, Kyrgyzstan and Tajikistan. The average activity concentration of (210)Pb and (210)Po in liver, muscle and bone of Carassius auratus was higher than the concentration in similar tissues of C. carpio and Sander lucioperca from the reference site. The accumulation of (210)Po was higher than for (210)Pb, and the accumulation of (210)Po was highest in the liver of C. auratus (3673 ± 434 Bq kg(-1) ww). Although the average activity concentration of (210)Pb in liver and bones of C. auratus from Pit Lake were fairly similar, a huge variation in the liver activity concentrations (25-327 Bq kg(-1) ww) was found. The results confirm direct uptake of unsupported (210)Po into the liver, and that the distributions of (210)Po and (210)Pb in fish organs were different. The BCF (L/kg) for (210)Po in bone, liver and muscle clearly demonstrates high accumulation of (210)Po in C. auratus, especially in the liver. The average BCFs of liver, bone and muscle were >1.4 × 10(5), >2.5 × 10(4) and >1.4 × 10(4), respectively. All fish in the Pit Lake were found to be in the same trophic level, however, a linear correlation between log (210)Po in liver and δ(15)N could indicate biomagnification of (210)Po in liver of C. auratus. In regards to the recommended Annual Limit of Intake (ALI) for (210)Po, the concentration of (210)Po in muscle tissues of C. auratus is alarming, as there is a high probability for the local population at risk to exceed the recommended ALI through consumption of fish from Taboshar Pit Lake.

  1. Is alpha spectrometry reliable for ²¹⁰Po urine bioassay?

    PubMed

    Li, Chunsheng; Sadi, Baki; Davis, Karelyn; Wyatt, Heather; Cornett, Jack; Kramer, Gary

    2011-01-01

    Typically the bioassay method for (210)Po in urine by alpha spectrometry (AS) involves wet decomposition of the sample, which may cause a loss of (210)Po if volatile species are present. To test this hypothesis, urine samples collected from two rats that were i.v. administered with polonium citrate were measured by both AS and liquid scintillation counting, where urine samples were mixed with a scintillation cocktail without any treatment. A split-plot design method was used to compare results from the two measurement methods, showing no evidence of a difference between the two methods. This suggests that the AS method is reliable for (210)Po urine bioassay.

  2. RbZnFe(PO4)2: synthesis and crystal structure

    PubMed Central

    Badri, Abdessalem; Ben Amara, Mongi

    2016-01-01

    A new iron phosphate, rubidium zinc iron(III) phosphate, RbZnFe(PO4)2, has been synthesized as single crystals by the flux method. This compound is isostructural to the previously reported KCoAl(PO4)2 [Chen et al. (1997 ▸). Acta Cryst. C53,1754–1756]. Its structure consists of a three-dimensional framework built up from corner-sharing PO4 and (Zn,Fe)O4 tetra­hedra. This mode of linkage forms channels parallel to the [100], [010] and [001] directions in which the Rb+ ions are located. PMID:27536385

  3. Bulk Superconductivity and Disorder in Single Crystals of LaFePO

    SciTech Connect

    Analytis, James G.; Chu, Jiun-Haw; Erickson, Ann S.; Kucharczyk, Chris; Serafin, Alessandro; Carrington, Antony; Cox, Catherine; Kauzlarich, Susan M.; Hope, Hakon; /UC, Davis. Dept. Chem.

    2010-02-15

    We have studied the intrinsic normal and superconducting properties of the oxypnictide LaFePO. These samples exhibit bulk superconductivity and the evidence suggests that stoichiometric LaFePO is indeed superconducting, in contrast to other reports. We find that superconductivity is independent of the interplane residual resistivity {rho}{sub 0} and discuss the implications of this on the nature of the superconducting order parameter. Finally we find that, unlike T{sub c}, other properties in single-crystal LaFePO including the resistivity and magnetoresistance, can be very sensitive to disorder.

  4. Comparison of LiMnPO4 made by Combustion and Hydrothermal Syntheses

    SciTech Connect

    Chen, Jiajun; Doeff, Marca M.; Wang, Ruigang

    2008-05-15

    Among the olivine-structured metal phosphate family, LiMnPO{sub 4} exhibits a high discharge potential (4V), which is still compatible with common electrolytes, making it interesting for use in the next generation of Li ion batteries. The extremely low electronic conductivity of this material severely limits its electrochemical performance, however. One strategy to overcome this limitation is to make LiMnPO{sub 4} nanoparticulate to decrease the diffusion distance. Another is to add a carbon or other conductive coating in intimate contact with the nanoparticles of the main phase, as is commonly done with LiFePO{sub 4}. The electrochemical performance of LiFePO{sub 4} is highly dependent on the quality of the carbon coatings on the particles [1-2], among other variables. Combustion synthesis allows the co-synthesis of nanoparticles coated with carbon in one step. Hydrothermal synthesis is used industrially to make LiFePO{sub 4} cathode materials [3] and affords a good deal of control over purity, crystallinity, and particle size. A wide range of olivine-structured materials has been successfully prepared by this technique [4], including LiMnPO{sub 4} in this study. In this paper, we report on the new synthesis of nano-LiMnPO{sub 4} by a combustion method. The purity is dependent upon the conditions used for synthesis, including the type of fuel and precursors that are chosen. The fuel to nitrate ratio influences the combustion temperature, which determines the type and amount of carbon found in the LiMnPO{sub 4} composites. This can further be modified by use of carbon structural modifiers added during a subsequent (optional) calcination step. Figure 1 shows a transmission electron microscopy (TEM) image of the spherical nano-sized LiMnPO{sub 4} particles typically formed by combustion synthesis. The average particle size is around 30 nm, in agreement with values obtained by the Rietveld refinement of XRD patterns. The small size of the particles cause the peak

  5. Comparison of LiMnPO4 made by Combustion and Hydrothermal Syntheses

    SciTech Connect

    Chen, Jiajun; Doeff, Marca M.; Wang, Ruigang

    2008-10-12

    Among the olivine-structured metal phosphate family, LiMnPO{sub 4} exhibits a high discharge potential (4V), which is still compatible with common electrolytes, making it interesting for use in the next generation of Li ion batteries. The extremely low electronic conductivity of this material severely limits its electrochemical performance, however. One strategy to overcome this limitation is to make LiMnPO{sub 4} nanoparticulate to decrease the diffusion distance. Another is to add a carbon or other conductive coating in intimate contact with the nanoparticles of the main phase, as is commonly done with LiFePO{sub 4}. The electrochemical performance of LiFePO{sub 4} is highly dependent on the quality of the carbon coatings on the particles, among other variables. Combustion synthesis allows the co-synthesis of nanoparticles coated with carbon in one step. Hydrothermal synthesis is used industrially to make LiFePO{sub 4} cathode materials and affords a good deal of control over purity, crystallinity, and particle size. A wide range of olivine-structured materials has been successfully prepared by this technique, including LiMnPO{sub 4} in this study. In this paper, we report on the new synthesis of nano-LiMnPO{sub 4} by a combustion method. The purity is dependent upon the conditions used for synthesis, including the type of fuel and precursors that are chosen. The fuel to nitrate ratio influences the combustion temperature, which determines the type and amount of carbon found in the LiMnPO{sub 4} composites. This can further be modified by use of carbon structural modifiers added during a subsequent (optional) calcination step. Figure 1 shows a transmission electron microscopy (TEM) image of the spherical nano-sized LiMnPO{sub 4} particles typically formed by combustion synthesis. The average particle size is around 30 nm, in agreement with values obtained by the Rietveld refinement of XRD patterns. The small size of the particles cause the peak broadening evident

  6. RbZnFe(PO4)2: synthesis and crystal structure.

    PubMed

    Badri, Abdessalem; Ben Amara, Mongi

    2016-08-01

    A new iron phosphate, rubidium zinc iron(III) phosphate, RbZnFe(PO4)2, has been synthesized as single crystals by the flux method. This compound is isostructural to the previously reported KCoAl(PO4)2 [Chen et al. (1997 ▸). Acta Cryst. C53,1754-1756]. Its structure consists of a three-dimensional framework built up from corner-sharing PO4 and (Zn,Fe)O4 tetra-hedra. This mode of linkage forms channels parallel to the [100], [010] and [001] directions in which the Rb(+) ions are located. PMID:27536385

  7. Seasonal variations of Pb-210 and Po-210 concentrations in an oligotrophic lake

    NASA Technical Reports Server (NTRS)

    Talbot, R. W.; Andren, A. W.

    1984-01-01

    In order to examine spatial and temporal variability during the seasonal cycle of the oligotrophic Crystal Lake, Wisconsin, vertical distribution measurements of Pb-210 and Po-210 in both the dissolved and particulate phases were conducted. Mass balance considerations indicate that the removal rates of the two isotopes from the water column to the sediment vary temporally by nearly an order of magnitude. The mean removal residence time was estimated to be 0.095 yr for Pb-210 and 0.26 yr for Po-210, suggesting a difference in the extent of water column recycling. Calculations indicate a cyclic response of the water column Po-210 inventory which corresponds to successive time periods when there were net losses or gains; this response may be due to rapid biological removal and subsequent release from the sediment of freshly deposited Po-210.

  8. Quantitative evaluation of 218Po behaviour in air in an artificial environment.

    PubMed

    Yajima, K; Hirao, S; Moriizumi, J; Yamazawa, H

    2015-11-01

    Experiments were carried out in a small enclosed booth for the purpose of understanding and modelling (218)Po behaviour. The experiment was conducted under two kinds of conditions without and with injection of incense smoke. A working model of (218)Po behaviour was applied to analyse the measured data. Under the condition without incense smoke, temporal changes in aerosol-attached and unattached (218)Po concentrations were successfully reproduced by the model. The deposition rate of unattached fraction and the rate of attachment were determined by the working model. Under the condition with incense smoke, temporal changes in (218)Po concentration were poorly simulated by the model. This can be attributed to the significantly increased aerosol concentration in small size ranges which is not properly considered in the attachment rate calculation in the model.

  9. Carbon coatings with olive oil, soybean oil and butter on nano-LiFePO 4

    NASA Astrophysics Data System (ADS)

    Kim, Ketack; Jeong, Ji Hwa; Kim, Ick-Jun; Kim, Hyun-Soo

    Kitchen oils (olive, soybean and butter) are selected for carbon coatings on LiFePO 4. The surface properties of LiFePO 4 are unknown or vary depending on synthetic methods. The multi-functional groups of fatty acids in the oils can orient properly to cope with the variable surface properties of LiFePO 4, which can lead to dense carbon coatings. The low price and low toxicity of kitchen oils are other advantages of the coating process. LiFePO 4 (D 50 = 121 nm)combined with the carbon coating enhances the rate capability. Capacities at the 2 C rate reach 150 mAh g -1 or higher. The charge retention values of 2.0 C/0.2 C are between 94.4 and 98.9%.

  10. Mutifuntional GdPO4:Eu3+ hollow spheres: synthesis and magnetic and luminescent properties.

    PubMed

    Zhang, Lihui; Yin, Meili; You, Hongpeng; Yang, Mei; Song, Yanhua; Huang, Yeju

    2011-11-01

    Mondispersed submicrometer GdPO(4):Eu(3+) hollow spheres were synthesized via an effective one-pot hydrothermal process. These hollow spheres have the average diameter of 200 nm, and the shell thickness is about 20 nm. The surface of the spheres consists of a number of nanorods with diameters of about 10 nm and lengths of about 50-80 nm. Both magnetic and luminescent properties of the obtained Eu(3+)-doped GdPO(4) hollow spheres were investigated. The hysteresis plot (M-H) analysis result indicates their paramagnetic property. The fluorescence spectra demonstrate that they emit orange-red color light originated from the (5)D(0) → (7)F(J) transitions of the Eu(3+) ions. Therefore, the obtained GdPO(4) hollow spheres hold promise for encapsulate drugs with controlled release. Moreover, the GdPO(4):Eu(3+) hollow spheres are attributes for bimodal magnetic resonance imaging (MRI)/optical bioimaging labeling.

  11. Hybrid potential model of the {alpha}-cluster structure of {sup 212}Po

    SciTech Connect

    Ibrahim, T. T.; Perez, S. M.; Wyngaardt, S. M.

    2010-09-15

    Cluster-core potentials derived microscopically or phenomenologically each have some desirable features. We combine these features in an analysis of the properties of {sup 212}Po treated as an {alpha}-{sup 208}Pb system.

  12. Dispersion, agglomeration, and gelation of LiFePO4 in water-based slurry

    NASA Astrophysics Data System (ADS)

    Tsai, Feng-Yen; Jhang, Jia-Hao; Hsieh, Han-Wei; Li, Chia-Chen

    2016-04-01

    The gelation of commercially available lithium iron phosphate (LiFePO4) in water-based slurry and its corresponding mechanism are studied. Based on surface chemistry analyses using zeta potential measurements and Fourier transform infrared spectroscopy, it is found that the key factor that causes LiFePO4 gelation in the aqueous slurry is the quality of the surface carbon coating on powder. When the surface carbon exhibits functional derivatives, such as carboxyl, hydroxyl, and carbonyl polar functional groups, LiFePO4 tends to form a three-dimensional, gel-like structure via hydrogen bonding. Moreover, the presence of the derivatives reduces the amount of conduction-favorable sp2-bonded carbon to LiFePO4, resulting in an electric resistance increase of the as-prepared electrode and the deterioration of the specific capacity of the as-constructed cell.

  13. Anode property of carbon coated LiFePO4 nanocrystals

    NASA Astrophysics Data System (ADS)

    Ni, Jiangfeng; Jiang, Jiaxing; Savilov, S. V.; Aldoshin, S. M.

    2016-10-01

    Nanostructured LiFePO4 is appealing cathode material for rechargeable lithium batteries. Herein, however, we report the intriguing anode properties of carbon coated LiFePO4 nanocrystals. In the potential range of 0-3.0 V, the LiFePO4 nanocrystal electrodes afford high reversible capacity of 373 mAhg-1 at a current rate of 0.05 Ag-1 and retains 239 mAhg-1 at a much higher rate of 1.25 Ag-1. In addition, it is capable of sustaining 1000 cycles at 1.25 Ag-1 without any capacity fading. Such superior properties indicate that nanostructured LiFePO4 could also be promising anode for rechargeable battery applications.

  14. Graphene Modified LiFePO4 Cathode Materials for High Power Lithium ion Batteries

    SciTech Connect

    Zhou, X.; Wang, F.; Zhu, Y.; Liu, Z.

    2011-01-24

    Graphene-modified LiFePO{sub 4} composite has been developed as a Li-ion battery cathode material with excellent high-rate capability and cycling stability. The composite was prepared with LiFePO{sub 4} nanoparticles and graphene oxide nanosheets by spray-drying and annealing processes. The LiFePO{sub 4} primary nanoparticles embedded in micro-sized spherical secondary particles were wrapped homogeneously and loosely with a graphene 3D network. Such a special nanostructure facilitated electron migration throughout the secondary particles, while the presence of abundant voids between the LiFePO{sub 4} nanoparticles and graphene sheets was beneficial for Li{sup +} diffusion. The composite cathode material could deliver a capacity of 70 mAh g{sup -1} at 60C discharge rate and showed a capacity decay rate of <15% when cycled under 10C charging and 20C discharging for 1000 times.

  15. Hydrothermal synthesis and tunable luminescence of NaBaPO4:Eu2+/Tb3+ phosphors

    NASA Astrophysics Data System (ADS)

    Wei, Zhen; Guan, Jinyu; Song, Juanjuan; Xu, Yongchun

    2015-12-01

    NaBaPO4:Eu2+/Tb3+ phosphors were synthesized by the hydrothermal process. The phase structure of obtained samples was characterized by powder X-ray diffraction. The morphology and size were obtained by field emission scanning electron microscope. Under the excitation at 346 nm, NaBaPO4:Eu2+/Tb3+ phosphors exhibited the emission band originating from the 4f65d1 → 4f7 transitions of Eu2+ and the emission bands originating from the 5D4 → 7Fj transitions of Tb3+. The intensities and lifetimes of Eu2+ decrease with increasing Tb3+ concentrations. On the basis of luminescence properties of NaBaPO4:Eu2+/Tb3+ phosphors, we can conclude the energy transfer occurs between Eu2+ and Tb3+ in NaBaPO4 host.

  16. Quantitative evaluation of 218Po behaviour in air in an artificial environment.

    PubMed

    Yajima, K; Hirao, S; Moriizumi, J; Yamazawa, H

    2015-11-01

    Experiments were carried out in a small enclosed booth for the purpose of understanding and modelling (218)Po behaviour. The experiment was conducted under two kinds of conditions without and with injection of incense smoke. A working model of (218)Po behaviour was applied to analyse the measured data. Under the condition without incense smoke, temporal changes in aerosol-attached and unattached (218)Po concentrations were successfully reproduced by the model. The deposition rate of unattached fraction and the rate of attachment were determined by the working model. Under the condition with incense smoke, temporal changes in (218)Po concentration were poorly simulated by the model. This can be attributed to the significantly increased aerosol concentration in small size ranges which is not properly considered in the attachment rate calculation in the model. PMID:25920782

  17. High pressure phase transformations in α-AlPO4: an x-ray diffraction investigation

    NASA Astrophysics Data System (ADS)

    Sharma, Surinder M.; Garg, Nandini; Sikka, S. K.

    2000-07-01

    We have re-investigated the high pressure behaviour of berlinite AlPO4 (α-AlPO4) with x-ray diffraction using a powerful synchrotron x-ray source SPring-8. Our results show that it transforms to a crystalline phase beyond ~13 GPa. Our data seem to be consistent with a CrVO4 type of structure in the Cmcm space group, similar to the high pressure phase observed in some isostructural phosphate compounds. The persistence of the diffraction pattern up to 40 GPa establishes that the previously accepted amorphization of AlPO4 around 12-18 GPa is incorrect. Experimental results suggest that the so-called memory glass effect observed earlier may in fact be the reversibility of the α-phase←⇔crystalline phase transformation. Comparisons of our experimental and theoretical results raise serious doubts about the theoretical understanding of the high pressure behaviour of α-AlPO4.

  18. High-pressure x-ray-diffraction study of α-AlPO4

    NASA Astrophysics Data System (ADS)

    Sharma, Surinder M.; Garg, Nandini; Sikka, S. K.

    2000-10-01

    Our high-pressure x-ray diffraction experiments on berlinite AlPO4 (α-AlPO4) show that it transforms to a crystalline Cmcm phase beyond 13 GPa. The persistence of diffraction pattern up to 40 GPa does not confirm the previous conclusions of high-pressure amorphization of AlPO4 around 12-18 GPa. Our experimental results, in agreement with earlier Raman scattering results, suggest that the so called memory glass effect observed earlier may in fact be due to the reversibility of α-phase<==>Cmcm phase transformation. These new experimental observations raise serious doubts about the theoretical understanding of the high-pressure behavior of α-AlPO4.

  19. Searching for “LiCr{sup II}PO{sub 4}”

    SciTech Connect

    Mosymow, E.; Glaum, R.; Kremer, R.K.

    2014-10-15

    The two new phosphates LiCr{sup II}{sub 4}(PO{sub 4}){sub 3} and Li{sub 5}Cr{sup II}{sub 2}Cr{sup III}(PO{sub 4}){sub 4} are discovered as equilibrium phases (ϑ=800 °C) in the quarternary system Li/Cr/P/O. Their crystal structures have been determined from single-crystal X-ray diffraction data (LiCr{sup II}{sub 4}(PO{sub 4}){sub 3}: violet-blue, Pnma (no. 62), Z=4, a=6.175(1) Å, b=14.316(3) Å, c=10.277(2) Å, 100 parameters, R{sub 1}=0.028, wR{sub 2}=0.08, 2060 unique reflections with F{sub o}>4σ(F{sub o}); Li{sub 5}Cr{sup II}{sub 2}Cr{sup III}(PO{sub 4}){sub 4}: greyish-green, P1{sup ¯} (no. 2), Z=1, a=4.9379(7) Å, b=7.917(2) Å, c=8.426(2) Å, α=109.98(2)°, β=90.71(1)°, γ=104.91(1)°, 131 parameters, R{sub 1}=0.022, wR{sub 2}=0.067, 1594 unique reflections with F{sub o}>4σ(F{sub o})). Li{sub 5}Cr{sup II}{sub 2}Cr{sup III}(PO{sub 4}){sub 4} adopts an hitherto unknown structure type. The crystal structure of LiCr{sup II}{sub 4}(PO{sub 4}){sub 3} is isotypic to that of NaCd{sup II}{sub 4}(PO{sub 4}){sub 3} and related to that of the mineral silicocarnotite Ca{sub 5}(PO{sub 4}){sub 2}(SiO{sub 4}). Significant disorder between Li{sup +} and Cr{sup 2+} is observed for both crystal structures. The oxidation states assigned to chromium in these two phosphates are in agreement with UV/vis/NIR absorption spectra and magnetic susceptibility data recorded for both compounds. Instead of “LiCr{sup II}PO{sub 4}” mixtures of LiCr{sup II}{sub 4}(PO{sub 4}){sub 3}, Li{sub 5}Cr{sup II}{sub 2}Cr{sup III}(PO{sub 4}){sub 4}, Cr{sub 2}O{sub 3}, and CrP are observed at equilibrium. Instead of “Li{sub 2}Cr{sup II}P{sub 2}O{sub 7}” four-phase mixtures consisting of Li{sub 9}Cr{sup III}{sub 3}(P{sub 2}O{sub 7}){sub 3}(PO{sub 4}){sub 2}, Li{sub 3}Cr{sup III}{sub 2}(PO{sub 4}){sub 3}, LiCrP{sub 2}O{sub 7}, and CrP were obtained. - Graphical abstract: Investigations on the equilibrium relations in the system Li/Cr/P/O revealed the two hitherto unknown phosphates Li{sub 5

  20. Determination of (210)Po in calcium supplements and the possible related dose assessment to the consumers.

    PubMed

    Strumińska-Parulska, Dagmara I

    2015-12-01

    The aim of this pioneer study was to investigate the most popular calcium supplements as a potential additional source of polonium (210)Po in human diet. The analyzed calcium pharmaceutics contained organic or inorganic calcium compounds; some from natural sources as mussels' shells, fish extracts, or sedimentary rocks. The objectives of this research were to investigate the naturally occurring (210)Po activity concentrations in calcium supplements, find the correlations between (210)Po concentration in medicament and calcium chemical form, and calculate the effective radiation dose connected to analyzed calcium supplement consumption. As results showed, (210)Po concentrations in natural origin calcium supplements (especially sedimentary rocks) were higher than the other analyzed. Also the results of (210)Po analysis obtained for inorganic forms of calcium supplements were higher. The highest (210)Po activity concentrations were determined in mineral tablets made from sedimentary rocks: dolomite and chalk - 3.88 ± 0.22 and 3.36 ± 0.10 mBq g(-1) respectively; while the lowest in organic calcium compounds: calcium lactate and calcium gluconate - 0.07 ± 0.02 and 0.17 ± 0.01 mBq g(-1). The annual effective radiation doses from supplements intake were estimated as well. The highest annual radiation dose from (210)Po taken with 1 tablet of calcium supplement per day was connected to sample made from chalk - 2.5 ± 0.07 μSv year(-1), while the highest annual radiation dose from (210)Po taken with 1 g of pure calcium per day was connected to dolomite - 12.7 ± 0.70 μSv year(-1).

  1. Po-210 as long-term integrating radon indicator in the indoor environment

    SciTech Connect

    Samuelsson, C.

    1990-07-01

    The general objective is to improve the knowledge about the transferring processes leading from airborne radon/radon daughters to embedded Po-210 in hard surfaces in the indoor environment. The specific goal of the research is to identify situations in which the surface activity of Po-210 can be used as a long-term indicator of lung cancer risk from past or future radon exposures.

  2. Combustion Synthesis of Ca3(PO4)2 Net-Shape Surgical Implants

    NASA Technical Reports Server (NTRS)

    Ayers, Reed A.; Castillo, Martin; Gottoli, Guglielmo; Moore, John J.; Simske, Steven J.

    2006-01-01

    Self-propagating high-temperature combustion synthesis (SHS) is the basis of a method of making components of porous tricalcium phosphate [Ca3(PO4)2] and related compounds in net sizes and shapes for use as surgical implants that are compatible with bone. The SHS method offers advantages over prior methods of manufacturing Ca3(PO4)2-based surgical implants.

  3. Online Workspace to Connect Scientists with NASA's Science E/PO Efforts and Practitioners

    NASA Astrophysics Data System (ADS)

    Shipp, Stephanie; Bartolone , Lindsay; Peticolas, Laura; Woroner, Morgan; Dalton, Heather; Schwerin, Theresa; Smith, Denise

    2014-11-01

    There is a growing awareness of the need for a scientifically literate public in light of challenges facing society today, and also a growing concern about the preparedness of our future workforce to meet those challenges. Federal priorities for science, technology, engineering, and math (STEM) education call for improvement of teacher training, increased youth and public engagement, greater involvement of underrepresented populations, and investment in undergraduate and graduate education. How can planetary scientists contribute to these priorities? How can they “make their work and findings comprehensible, appealing, and available to the public” as called for in the Planetary Decadal Survey?NASA’s Science Mission Directorate (SMD) Education and Public Outreach (E/PO) workspace provides the SMD E/PO community of practice - scientists and educators funded to conduct SMD E/PO or those using NASA’s science discoveries in E/PO endeavors - with an online environment in which to communicate, collaborate, and coordinate activities, thus helping to increase effectiveness of E/PO efforts. The workspace offers interested scientists avenues to partner with SMD E/PO practitioners and learn about E/PO projects and impacts, as well as to advertise their own efforts to reach a broader audience. Through the workspace, scientists can become aware of opportunities for involvement and explore resources to improve professional practice, including literature reviews of best practices for program impact, mechanisms for engaging diverse audiences, and large- and small-scale program evaluation. Scientists will find “how to” manuals for getting started and increasing impact with public presentations, classroom visits, and other audiences, as well as primers with activity ideas and resources that can augment E/PO interactions with different audiences. The poster will introduce the workspace to interested scientists and highlight pathways to resources of interest that can help

  4. Modeling Li-ion conductivity in LiLa(PO3)4 powder

    NASA Astrophysics Data System (ADS)

    Mounir, Ferhi; Karima, Horchani-Naifer; Khaled, Ben Saad; Mokhtar, Férid

    2012-07-01

    Polycrystalline powder and single-crystal of LiLa(PO3)4 are synthesized by solid state reaction and flux technique, respectively. A morphological description of the obtained product was made based on scanning electron microscopy micrographs. The obtained powder was characterized by X-ray powder diffraction, FTIR and Raman spectroscopies. Ionic conductivity of the LiLa(PO3)4 powder was measured and evaluated over a temperature range from 553 to 913 K. Single crystals of LiLa(PO3)4 are characterized by single-crystal X-ray diffraction. The LiLa(PO3)4 structure was found to be isotypic with LiNd(PO3)4. It crystallizes in the monoclinic system with space group C2/c and cell parameters: a=16.635(6) Å, b=7.130(3) Å, c=9.913(3) Å, β=126.37(4)°, V=946.72(6) Å3 and Z=4. The LiLa(PO3)4 structure was described as an alternation between spiraling chains (PO3)n and (La3+, Li+) cations along the b direction. The small Li+ ions, coordinated to four oxygen atoms, were located in the large connected cavities created between the LaO8 polyhedra and the polyphosphate chains. The jumping of Li+ through tunnels of the crystalline network was investigated using complex impedance spectroscopy. The close value of the activation energies calculated through the analysis of conductivity data and loss spectra indicate that the transport in the investigated system is through hopping mechanism. The correlation between ionic conductivity of LiLa(PO3)4 and its crystallographic structure was investigated and the most probably transport pathway model was determined.

  5. Determination of (210)Po in calcium supplements and the possible related dose assessment to the consumers.

    PubMed

    Strumińska-Parulska, Dagmara I

    2015-12-01

    The aim of this pioneer study was to investigate the most popular calcium supplements as a potential additional source of polonium (210)Po in human diet. The analyzed calcium pharmaceutics contained organic or inorganic calcium compounds; some from natural sources as mussels' shells, fish extracts, or sedimentary rocks. The objectives of this research were to investigate the naturally occurring (210)Po activity concentrations in calcium supplements, find the correlations between (210)Po concentration in medicament and calcium chemical form, and calculate the effective radiation dose connected to analyzed calcium supplement consumption. As results showed, (210)Po concentrations in natural origin calcium supplements (especially sedimentary rocks) were higher than the other analyzed. Also the results of (210)Po analysis obtained for inorganic forms of calcium supplements were higher. The highest (210)Po activity concentrations were determined in mineral tablets made from sedimentary rocks: dolomite and chalk - 3.88 ± 0.22 and 3.36 ± 0.10 mBq g(-1) respectively; while the lowest in organic calcium compounds: calcium lactate and calcium gluconate - 0.07 ± 0.02 and 0.17 ± 0.01 mBq g(-1). The annual effective radiation doses from supplements intake were estimated as well. The highest annual radiation dose from (210)Po taken with 1 tablet of calcium supplement per day was connected to sample made from chalk - 2.5 ± 0.07 μSv year(-1), while the highest annual radiation dose from (210)Po taken with 1 g of pure calcium per day was connected to dolomite - 12.7 ± 0.70 μSv year(-1). PMID:26318774

  6. Sky Fest: A Model of Successful Scientist Participation in E/PO

    NASA Astrophysics Data System (ADS)

    Dalton, H.; Shipp, S. S.; Shaner, A. J.; LaConte, K.; Shupla, C. B.

    2014-12-01

    Participation in outreach events is an easy way for scientists to get involved with E/PO and reach many people with minimal time commitment. At the Lunar and Planetary Institute (LPI) in Houston, Texas, the E/PO team holds Sky Fest outreach events several times a year. These events each have a science content theme and include several activities for children and their parents, night sky viewing through telescopes, and scientist presentations. LPI scientists have the opportunity to participate in Sky Fest events either by helping lead an activity or by giving the scientist presentation (a short lecture and/or demonstration). Scientists are involved in at least one preparation meeting before the event. This allows them to ask questions, understand what activity they will be leading, and learn the key points that they should be sharing with the public, as well as techniques for effectively teaching members of the public about the event topic. During the event, each activity is run by one E/PO specialist and one scientist, enabling the scientist to learn about effective E/PO practices from the E/PO specialist and the E/PO specialist to get more science information about the event topic. E/PO specialists working together with scientists at stations provides a more complete, richer experience for event participants. Surveys of event participants have shown that interacting one-on-one with scientists is often one of their favorite parts of the events. Interviews with scientists indicated that they enjoyed Sky Fest because there was very little time involved on their parts outside of the actual event; the activities were created and/or chosen by the E/PO professionals, and setup for the events was completed before they arrived. They also enjoyed presenting their topic to people without a background in science, and who would not have otherwise sought out the information that was presented.

  7. Fractionation of 210Po and 210Pb in coastal waters of the NW Mediterranean continental margin

    NASA Astrophysics Data System (ADS)

    Tateda, Yutaka; Carvalho, Fernando P.; Fowler, Scott W.; Miquel, Juan-Carlos

    2003-03-01

    The natural radionuclides 210Po and 210Pb were analyzed in samples of surface sea water, rain and dry fallout, and river water collected along the NW Mediterranean coast as well as from a sediment trap moored 3 km south of Monaco. Using a box model calculation, the balances and fluxes of 210Po and 210Pb in the coastal waters of the NW Mediterranean were estimated. Atmospheric inputs of 210Po and 210Pb to Monaco coastal waters varied seasonally and were maximal in winter when storms and strong winds transfered continental 222Rn-rich air and aerosols of top soil particles to coastal surface waters, which in turn enhanced the 210Po and 210Pb input to these waters. The balance estimation using all fluxes in surface waters indicated that 210Pb was removed from surface water with residence times of 2.1, 0.40, and 2.7 years for dissolved, particulate, and total 210Pb, respectively. In the bottom water and surface sediments, additional excess 210Pb sinking and sedimentation fluxes were observed, suggesting a substantial down slope transport of sediment particles. Similarly, the residence times of 210Po in surface water were 1.2, 0.38, and 0.77 years for dissolved, particulate, and total 210Po, respectively; however, a deficit in the 210Po sinking flux in the bottom layer, compared to removal flux from the surface waters, suggested rapid degradation of 210Po-bearing biogenic particles during sinking following periods of low biological productivity.

  8. Changing hydrological conditions in the Po basin under global warming.

    PubMed

    Coppola, Erika; Verdecchia, Marco; Giorgi, Filippo; Colaiuda, Valentina; Tomassetti, Barbara; Lombardi, Annalina

    2014-09-15

    The Po River is a crucial resource for the Italian economy, since 40% of the gross domestic product comes from this area. It is thus crucial to quantify the impact of climate change on this water resource in order to plan for future water use. In this paper a mini ensemble of 8 hydrological simulations is completed from 1960 to 2050 under the A1B emission scenario, by using the output of two regional climate models as input (REMO and RegCM) at two different resolutions (25 km-10 km and 25 km-3 km). The river discharge at the outlet point of the basin shows a change in the spring peak of the annual cycle, with a one month shift from May to April. This shift is entirely due to the change in snowmelt timing which drives most of the discharge during this period. Two other important changes are an increase of discharge in the wintertime and a decrease in the fall from September to November. The uncertainty associated with the winter change is larger compared to that in the fall. The spring shift and the fall decrease of discharge imply an extension of the hydrological dry season and thus an increase in water stress over the basin. The spatial distributions of the discharge changes are in agreement with what is observed at the outlet point and the uncertainty associated with these changes is proportional to the amplitude of the signal. The analysis of the changes in the anomaly distribution of discharge shows that both the increases and decreases in seasonal discharge are tied to the changes in the tails of the distribution, i.e. to the increase or decrease of extreme events.

  9. Variation of ²¹⁰Po daily urinary excretion for male subjects at environmental level.

    PubMed

    Hölgye, Z; Hýža, M; Mihalík, J; Rulík, P; Škrkal, J

    2015-05-01

    (210)Po was determined in 24-h urine of seven healthy males from Prague, Czech Republic, for ten consecutive days. The results show that for each volunteer, the urinary excretion of (210)Po changed only little from day to day in the studied time period. For two volunteers, the difference in the daily excreted (210)Po activity for two consecutive days was not significant, given the 95% confidence interval (two sigma) of the activity measurements. The same is valid for the excretion data of the other volunteers, except for some days where the differences were slightly higher. The range of daily urinary excretion of (210)Po of each volunteer in the studied time period was quite narrow. Among the volunteers, the maximum daily urinary excretion value of (210)Po was at most about a factor of 2.5 higher than the lowest excretion value. An attempt to explain the observed small inter-individual variability of (210)Po excretion in daily urine is made.

  10. Optimization of LiFePO4 Nanoparticle Suspensions with Polyethyleneimine for Aqueous Processing

    SciTech Connect

    Li, Jianlin; Armstrong, Beth L; Kiggans, Jim; Daniel, Claus; Wood III, David L

    2012-01-01

    Addition of dispersants to aqueous based lithium-ion battery electrode formulations containing LiFePO{sub 4} is critical to obtaining a stable suspension. The resulting colloidal suspensions enable dramatically improved coating deposition when processing electrodes. This research examines the colloidal chemistry modifications based on polyethyleneimine (PEI) addition and dispersion characterization required to produce high quality electrode formulations and coatings for LiFePO{sub 4} active cathode material. The isoelectric point, a key parameter in characterizing colloidal dispersion stability, of LiFePO{sub 4} and super P C45 were determined to be pH = 4.3 and 3.4, respectively. PEI, a cationic surfactant, was found to be an effective dispersant. It is demonstrated that 1.0 wt % and 0.5 wt % PEI were required to stabilize the LiFePO{sub 4} and super P C45 suspension, respectively. LiFePO{sub 4} cathode suspensions with 1.5 wt % PEI demonstrated the best dispersibility of all components, as evidenced by viscosity and agglomerate size of the suspensions and elemental distribution within dry cathodes. The addition of PEI significantly improved the LiFePO{sub 4} performance.

  11. Nano DCPA-whisker composites with high strength and Ca and PO(4) release.

    PubMed

    Xu, H H K; Sun, L; Weir, M D; Antonucci, J M; Takagi, S; Chow, L C; Peltz, M

    2006-08-01

    The main challenges facing composite restorations are secondary caries and bulk fracture. The objective of this study was to develop nano DCPA (dicalcium phosphate anhydrous)-whisker composites with high strength and Ca and PO(4) ion release to combat caries. Flexural strength for the nano DCPA-whisker composites at a nano DCPA:whisker mass ratio of 1:2 ranged from (148 +/- 9) MPa to (167 +/- 23) MPa, significantly higher than the (103 +/- 32) MPa of an inlay/onlay commercial control composite without Ca-PO(4) release. The nano DCPA-whisker composite released PO(4) to a concentration of (1.95 +/- 0.13) mmol/L and Ca of (0.68 +/- 0.05) mmol/L. Compared with previous conventional Ca- and PO(4)-releasing composites, the nano DCPA-whisker composites had strengths two-fold higher, and released comparable or higher levels of Ca and PO(4). In conclusion, combining nano-DCPA with whiskers yielded novel composites that released high levels of Ca and PO(4) requisite for remineralization. These high-strength composites may provide a unique combination of stress-bearing and caries-inhibiting capabilities.

  12. Structure of C3PO and mechanism of human RISC activation

    SciTech Connect

    Ye, Xuecheng; Huang, Nian; Liu, Ying; Paroo, Zain; Huerta, Carlos; Li, Peng; Chen, She; Liu, Qinghua; Zhang, Hong

    2011-08-26

    Assembly of the RNA-induced silencing complex (RISC) consists of loading duplex (guide-passenger) siRNA onto Argonaute (Ago2) and removing the passenger strand. Ago2 contributes critically to RISC activation by nicking the passenger strand. Here we reconstituted duplex siRNA-initiated RISC activity using recombinant human Ago2 (hAgo2) and C3PO, indicating that C3PO has a critical role in hAgo2-RISC activation. Consistently, genetic depletion of C3PO compromised RNA silencing in mammalian cells. We determined the crystal structure of hC3PO, which reveals an asymmetric octamer barrel consisting of six translin and two TRAX subunits. This asymmetric assembly is critical for the function of C3PO as an endonuclease that cleaves RNA at the interior surface. The current work supports a Dicer-independent mechanism for human RISC activation, in which Ago2 directly binds duplex siRNA and nicks the passenger strand, and then C3PO activates RISC by degrading the Ago2-nicked passenger strand.

  13. Hydrothermal Synthesis and Luminescence Property of Nanoscaled BiPO4:Eu3+ Powders.

    PubMed

    Shi, Xiaolei; Liu, Yun; Zhang, Jin; Zhang, Kun; Li, Peng; Zuo, Haoqiang

    2016-04-01

    A series of Bi1-xPO4:xEu3+ phosphors were prepared using a simple hydrothermal method. The effects of pH and Eu3+ doping on the structure, morphology and luminescence properties of BiPO4:Eu3+ were investigated systematically. X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM) results reveal that the as-prepared BiPO4 crystals are in a low temperature monoclinic phase (LTMP), and have a rod-like structure with a size in the range of 1-5 µm at pH 1. Increasing the pH to 2 transforms the BiPO4 to its hexagonal phase (HP), with peanut-like structures ranging from 50 to 150 nm. At pH 1, when the doping level is increased to 0.07, the phase transformation from LTMP to HP occurs, meaning that the amount of HP components increase with increasing Eu3+ doping. Furthermore, all the diffraction peaks of the Bi1-xPO4:xEu3+ can be fitted very well to HP when x = 0.11. The photoluminescence (PL) spectra suggest that orange-red luminescence can be observed in the series of BiPO4:Eu3+ phosphors, and that concentration quenching occurs when x = 0.07. PMID:27451718

  14. Fabrication and luminescence of BiPO4:Tb3+/Ce3+ nanofibers by electrospinning

    NASA Astrophysics Data System (ADS)

    Yang, Yuguo; Liu, Bing; Zhang, Yuanyuan; Lv, Xianshun; Wei, Lei; Wang, Xuping

    2016-02-01

    BiPO4:Tb3+/Ce3+ nanofibers are synthesized by a simple electrospinning process and followed by a calcination treatment. The nanofibers are characterized by TG-DSC, XRD, FT-IR, SEM, TEM, and spectrophotometer. The calcined BiPO4:Tb3+/Ce3+ nanofibers have a monoclinic phase and the diameters are in the range of 80-200 nm. The SEM and TEM images show that the nanofibers are mesoporous and composed of lots of linked nanoparticles. Under an excitation at 369 nm, BiPO4:Tb3+ and BiPO4:Tb3+/Ce3+ nanofibers show characteristic emission bands originating from the 5D4 → 7Fj (j = 6, 5, 4, and 3) transitions of Tb3+ ions. The luminescent properties of BiPO4:Tb3+ indicate that the quenching concentration for Tb3+ ions in BiPO4 host is about 15 mol%. The co-doped Ce3+ ions can improve the emission intensity through the energy transfer from Ce3+ to Tb3+ ions.

  15. Nano DCPA-Whisker Composites with High Strength and Ca and PO4 Release

    PubMed Central

    Xu, H.H.K.; Sun, L.; Weir, M.D.; Antonucci, J.M.; Takagi, S.; Chow, L.C.; Peltz, M.

    2008-01-01

    The main challenges facing composite restorations are secondary caries and bulk fracture. The objective of this study was to develop nano DCPA (dicalcium phosphate anhydrous)-whisker composites with high strength and Ca and PO4 ion release to combat caries. Flexural strength for the nano DCPA-whisker composites at a nano DCPA:whisker mass ratio of 1:2 ranged from (148 ± 9) MPa to (167 ± 23) MPa, significantly higher than the (103 ± 32) MPa of an inlay/onlay commercial control composite without Ca-PO4 release. The nano DCPA-whisker composite released PO4 to a concentration of (1.95 ± 0.13) mmol/L and Ca of (0.68 ± 0.05) mmol/L. Compared with previous conventional Ca- and PO4-releasing composites, the nano DCPA-whisker composites had strengths two-fold higher, and released comparable or higher levels of Ca and PO4. In conclusion, combining nano-DCPA with whiskers yielded novel composites that released high levels of Ca and PO4 requisite for remineralization. These high-strength composites may provide a unique combination of stress-bearing and caries-inhibiting capabilities. PMID:16861289

  16. Variation of ²¹⁰Po daily urinary excretion for male subjects at environmental level.

    PubMed

    Hölgye, Z; Hýža, M; Mihalík, J; Rulík, P; Škrkal, J

    2015-05-01

    (210)Po was determined in 24-h urine of seven healthy males from Prague, Czech Republic, for ten consecutive days. The results show that for each volunteer, the urinary excretion of (210)Po changed only little from day to day in the studied time period. For two volunteers, the difference in the daily excreted (210)Po activity for two consecutive days was not significant, given the 95% confidence interval (two sigma) of the activity measurements. The same is valid for the excretion data of the other volunteers, except for some days where the differences were slightly higher. The range of daily urinary excretion of (210)Po of each volunteer in the studied time period was quite narrow. Among the volunteers, the maximum daily urinary excretion value of (210)Po was at most about a factor of 2.5 higher than the lowest excretion value. An attempt to explain the observed small inter-individual variability of (210)Po excretion in daily urine is made. PMID:25712002

  17. Radioluminescence properties of Ce 3+-activated MGd(PO 3) 4 (M = Li, Na, K, Cs)

    NASA Astrophysics Data System (ADS)

    Zhong, Jiuping; Liang, Hongbin; Su, Qiang; Zhou, Jianying; Khodyuk, Ivan V.; Dorenbos, Pieter

    2009-12-01

    Rare-earth phosphates MGd(PO 3) 4:1.0 mol% Ce 3+ (M = Li, Na, K, Cs) powder samples were prepared by a solid-state reaction technique at high temperature. The radioluminescence spectra and light-yield characteristic of MGd(PO 3) 4:Ce 3+ under X-ray irradiation were determined. It was found that, from LiGd(PO 3) 4:Ce 3+ to CsGd(PO 3) 4:Ce 3+, with the increasing of M + radius, the doublet emission energy of Ce 3+ ions decrease gradually but the light-yield increase significantly. Especially, CsGd(PO 3) 4:1.0 mol% Ce 3+ has the highest X-ray excited light-yield of 24,400 photons/MeV with maximal emission peaks at 337 nm and 358 nm at room temperature. Due to its suitable emission wavelength range, high light-yield, high chemical stability and fast luminescence decay of Ce 3+ emission, CsGd(PO 3) 4:Ce 3+ may be a promising scintillation material.

  18. Rapid functional analysis in Xenopus oocytes of Po protein adhesive interactions.

    PubMed

    Yoshida, M; Colma, D R

    2001-06-01

    We have developed a coupled Xenopus oocyte expression system for evaluating the functional effects of mutations in known or suspected adhesion molecules, which allows for a very rapid assessment of intercellular adhesion. As a model protein, we first used Protein zero (Po), an adhesion molecule that mediates self-adhesion of the Schwann cell plasma membrane to form compact myelin in the mammalian PNS. A wide variety of mutations in Po cause certain human peripheral neuropathies, such as the Charcot-Marie-Tooth disease (CMT) type 1B and Dejerine-Sottas syndrome (DSS). After wild-type Po mRNA is injected, the protein is synthesized and correctly targeted to the oocyte cell surface. When two oocytes are paired, wild-type Po redistributes and concentrates at the cell-cell apposition region, and by electron microscopy, the oocyte pairs show close cell-cell appositions and are devoid of the microvilli that are observed in uninjected oocyte pairs. These are hallmark features of highly adhesive cell:cell interfaces. Several point mutations in Po were engineered, corresponding to the molecular defects in the CMT type 1B or DSS. The proteins encoded by these mutations reached the cell surface but failed to concentrate at the oocyte interface. Po carrying a point mutation that is found in DSS is not targeted on the plasma membrane and fail to accumulate at the cell-cell contact site. PMID:11519730

  19. Hydrothermal growth and morphology evolution of CePO{sub 4} aggregates by a complexing method

    SciTech Connect

    Ma Lin; Chen Weixiang Zheng Yifan; Xu Zhude

    2008-11-03

    A facile hydrothermal route assisted by Na{sub 2}H{sub 2}EDTA (ethylenediaminetetraacetic acid disodium) has been successfully developed to prepare uniform cerium phosphate (CePO{sub 4}) aggregates with different morphologies, such as peanut-like and spindle-like. It was found that the as-prepared uniform CePO{sub 4} aggregates were constructed with many nearly parallel aligned nanorods. The molar ratio of EDTA/Ce{sup 3+}, solution pH and reaction time had great influences on the morphologies and sizes of the CePO{sub 4} samples. In our process of synthesis, Na{sub 2}H{sub 2}EDTA played important roles as complexing reagent and inducing agent on the formation of CePO{sub 4} aggregates. The possible growth mechanism for CePO{sub 4} aggregates was presented. Ce{sub 0.9}Tb{sub 0.1}PO{sub 4} aggregates with different morphologies were also prepared and their photoluminescence properties were characterized.

  20. Hydroxyapatite supported Ag3PO4 nanoparticles with higher visible light photocatalytic activity

    NASA Astrophysics Data System (ADS)

    Hong, Xiaoting; Wu, Xiaohui; Zhang, Qiuyun; Xiao, Mingfeng; Yang, Gelin; Qiu, Meirong; Han, Guocheng

    2012-03-01

    Hydroxyapatite supported Ag3PO4 nanocomposites have been synthesized by a wet impregnation process. UV-vis absorption spectra show a red shift of the absorption edges for the composite systems compared to pure hydroxyapatite support. The surface structure and morphology of the nanocomposites were characterized by Brunauer-Emmett-Teller (BET) apparatus, X-ray diffraction (XRD), transmission electron microscopy (TEM). The results suggest that Ag3PO4 nanoparticles (6-17 nm in diameter) are well dispersed on the hydroxyapatite support and Ag3PO4 nanoparticles density is larger for the higher Ag+ loading sample. The as-prepared nanocomposite photocatalysts showed a pronounced photocatalytic activity upon decomposition of methylene blue dye in aqueous solution under both visible light (wavelength > 400 nm) and UV-vis light irradiation. A synergic mechanism of inherent photocatalytic capability of Ag3PO4 and the accelerated electron/hole separation resulting from the photoinduced electrons captured by the slow-released Ag+ at the interface of Ag3PO4 and hydroxyapatite is proposed for the nanocomposites on the enhancement of photocatalytic performance in comparison to that of pure Ag3PO4 nanoparticles. The support of hydroxyapatite may also act as an absorbent which favors the mass transfer in heterogeneous photocatalysis reaction.

  1. The Legacy of NASA Astrophysics E/PO: Conducting Professional Development, Developing Key Themes & Resources, and Broadening E/PO Audiences

    NASA Astrophysics Data System (ADS)

    Lawton, Brandon L.; Smith, Denise A.; Meinke, Bonnie K.; Bartolone, Lindsay; Manning, Jim; Schultz, Gregory R.; NASA Astrophysics E/PO Community

    2016-01-01

    For the past six years, NASA's Science Mission Directorate (SMD) has coordinated the work of its mission- and program-embedded education and public outreach (E/PO) efforts through four forums representing its four science divisions. The Astrophysics Forum, as the others, has built on SMD's long-standing principle of partnering scientists and educators and embedding E/PO in its missions to encourage and coordinate collaborative efforts to make the most efficient and effective use of NASA resources, personnel, data and discoveries in leveraged ways, in support of the nation's science education. Three priorities established early in the Forum's period of activity were to collaboratively enhance professional development for formal and informal educators, develop key themes & resources centered on astrophysics topics, and broaden the reach of astrophysics E/PO to traditionally underserved audiences in STEM subjects. This presentation will highlight some of the achievements of the Astrophysics E/PO community and Forum in these priority areas. This work constitutes an ongoing legacy--a firm foundation on which the new structure of NASA SMD education efforts will go forward.

  2. Probing the interface of core shell particles of GaPO 4 and AlPO 4 by 31P MAS NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Kulshreshtha, S. K.; Jayakumar, O. D.; Vishwanadh, B.; Sudarsan, V.

    2011-02-01

    Hexagonal GaPO 4, pseudo-hexagonal AlPO 4 and the core shell particles of these phosphates have been prepared in ethylene glycol medium at 180 °C, followed by annealing at 900 °C for 24 h and investigated by powder X-ray diffraction and 31P Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) techniques. The 31P NMR studies of these core shell particles showed a multi-component NMR pattern consisting of five peaks originating due to the distinct structural configurations formed by the varying number of Al 3+ and Ga 3+ as the next nearest neighbors around the probe 31P nuclei of the PO 4 tetrahedron. Existence of different PO 4 structural units with varying number of Al 3+ and Ga 3+ as its next nearest neighbors around P nucleus at the interface of the core shell particles has been confirmed. These results clearly indicate the bond formation at the interface between the core and shell material for these particles.

  3. Energetics of cobalt phosphate frameworks: {alpha}, {beta}, and red NaCoPO{sub 4}

    SciTech Connect

    Le, So-Nhu; Eng, Hank W.; Navrotsky, Alexandra . E-mail: anavrotsky@ucdavis.edu

    2006-12-15

    Thermal behavior, relative stability, and enthalpy of formation of {alpha} (pink phase), {beta} (blue phase), and red NaCoPO{sub 4} are studied by differential scanning calorimetry, X-ray diffraction, and high-temperature oxide melt drop solution calorimetry. Red NaCoPO{sub 4} with cobalt in trigonal bipyramidal coordination is metastable, irreversibly changing to {alpha} NaCoPO{sub 4} at 827 K with an enthalpy of phase transition of -17.4{+-}6.9 kJ mol{sup -1}. {alpha} NaCoPO{sub 4} with cobalt in octahedral coordination is the most stable phase at room temperature. It undergoes a reversible phase transition to the {beta} phase (cobalt in tetrahedra) at 1006 K with an enthalpy of phase transition of 17.6{+-}1.3 kJ mol{sup -1}. Enthalpy of formation from oxides of {alpha}, {beta}, and red NaCoPO{sub 4} are -349.7{+-}2.3, -332.1{+-}2.5, and -332.3{+-}7.2 kJ mol{sup -1}; standard enthalpy of formation of {alpha}, {beta}, and red NaCoPO{sub 4} are -1547.5{+-}2.7, -1529.9{+-}2.8, and -1530.0{+-}7.3 kJ mol{sup -1}, respectively. The more exothermic enthalpy of formation from oxides of {beta} NaCoPO{sub 4} compared to a structurally related aluminosilicate, NaAlSiO{sub 4} nepheline, results from the stronger acid-base interaction of oxides in {beta} NaCoPO{sub 4} (Na{sub 2}O, CoO, P{sub 2}O{sub 5}) than in NaAlSiO{sub 4} nepheline (Na{sub 2}O, Al{sub 2}O{sub 3}, SiO{sub 2}). - Graphical abstract: Relative stability of NaCoPO{sub 4} polymorphs compared to the most stable phase, {alpha} NaCoPO{sub 4}.

  4. A chemically activated graphene-encapsulated LiFePO4 composite for high-performance lithium ion batteries.

    PubMed

    Ha, Jeonghyun; Park, Seung-Keun; Yu, Seung-Ho; Jin, Aihua; Jang, Byungchul; Bong, Sungyool; Kim, In; Sung, Yung-Eun; Piao, Yuanzhe

    2013-09-21

    A composite of modified graphene and LiFePO4 has been developed to improve the speed of charging-discharging and the cycling stability of lithium ion batteries using LiFePO4 as a cathode material. Chemically activated graphene (CA-graphene) has been successfully synthesized via activation by KOH. The as-prepared CA-graphene was mixed with LiFePO4 to prepare the composite. Microscopic observation and nitrogen sorption analysis have revealed the surface morphologies of CA-graphene and the CA-graphene/LiFePO4 composite. Electrochemical properties have also been investigated after assembling coin cells with the CA-graphene/LiFePO4 composite as a cathode active material. Interestingly, the CA-graphene/LiFePO4 composite has exhibited better electrochemical properties than the conventional graphene/LiFePO4 composite as well as bare LiFePO4, including exceptional speed of charging-discharging and excellent cycle stability. That is because the CA-graphene in the composite provides abundant porous channels for the diffusion of lithium ions. Moreover, it acts as a conducting network for easy charge transfer and as a divider, preventing the aggregation of LiFePO4 particles. Owing to these properties of CA-graphene, LiFePO4 could demonstrate enhanced and stably long-lasting electrochemical performance.

  5. Synthesis and structure of Ce1-xEuxPO4 solid solutions for minor actinides immobilization

    NASA Astrophysics Data System (ADS)

    Wang, Xiaohuan; Teng, Yuancheng; Huang, Yi; Wu, Lang; Zeng, Pan

    2014-08-01

    Ce1-xEuxPO4 (x = 0-1) solid solutions were synthesized by the solid state reaction process using europium (Eu) as the surrogate for trivalent minor actinide americium (Am). The effects of calcination temperature, holding time and Eu content on the crystalline phase, microstructure and morphology of Ce1-xEuxPO4 (x = 0-1) were investigated. The monazite-type EuPO4 and CePO4 coexisted after being calcined at 1000 °C for 4 h, suggesting the CePO4 and EuPO4 phases would form initially separately. Pure and single-phase monazite-type Ce1-xEuxPO4 (x = 0-1) powders were obtained at 1300 °C for 4 h. The results of the XRD patterns Rietveld refinement and μ-Raman analysis confirmed the formation of a Ce1-xEuxPO4 (x = 0-1) continuous solid solution. The grain size of Ce0.5Eu0.5PO4 increased obviously as the holding time extended. The Ce, Eu, P and O elements were almost distributed homogeneously in the Ce0.5Eu0.5PO4 solid solution.

  6. Synthesis, structures and properties of the new lithium cobalt(II) phosphate Li4Co(PO4)2

    NASA Astrophysics Data System (ADS)

    Glaum, R.; Gerber, K.; Schulz-Dobrick, M.; Herklotz, M.; Scheiba, F.; Ehrenberg, H.

    2012-04-01

    α-Li4Co(PO4)2 has been synthesized and crystallized by solid-state reactions. The new phosphate crystallizes in the monoclinic system (P21/a, Z=4, a=8.117(3) Å, b=10.303(8) Å, c=8.118(8) Å, β=104.36(8) Å) and is isotypic to α-Li4Zn(PO4)2. The structure of α-Li4Co(PO4)2 has been determined from single-crystal X-ray diffraction data {R1=0.040, wR2=0.135, 2278 unique reflections with Fo>4σ(Fo)}. The crystal structure, which might be regarded as a superstructure of the wurtzite structure type, is build of layers of regular CoO4, PO4 and Li1O4 tetrahedra. Lithium atoms Li2, Li3 and Li4 are located between these layers. Thermal investigations by in-situ XRPD, DTA/TG and quenching experiments suggest decomposition followed by formation and phase transformation of Li4Co(PO4)2: α-Li4Co(PO4)2⟹442 °Cβ-Li3PO4+LiCoPO4⇌773 °Cβ-Li4Co(PO4)2⟹quenching to 25 °Cα-Li4Co(PO4)2 According to HT-XRPD at ϑ=850 °Cβ-Li4Co(PO4)2 (Pnma, Z=2, 10.3341(8) Å, b=6.5829(5) Å, c=5.0428(3) Å) is isostructural to γ-Li3PO4. The powder reflectance spectrum of α-Li4Co(PO4)2 shows the typical absorption bands for the tetrahedral chromophore [CoIIO4].

  7. A large excess of 210Po in the overlying water of the Zhubi Coral Reef flat, in the South China Sea.

    PubMed

    Yang, W F; Huang, Y P; Chen, M; Qiu, Y S; Li, H B; Zhang, L

    2011-05-01

    The temporal variability of (210)Po and (210)Pb was examined in the overlying water of the Zhubi Coral Reef flat to detect nutrient-like behavior of (210)Po. Different mechanisms influencing their geochemical behaviors were observed. Excess (210)Po relative to (210)Pb revealed an additional input of (210)Po other than in situ production from (210)Pb. The (210)Po input comes from the reef flat sediment through diffusion. The diffusion contributes 62% of the total (210)Po. This diffusion of (210)Po directly highlights its nutrient-like behavior. No input, but the slight removal, of (210)Pb was observed. Fractionation factors indicate that particulate matter prefers to adsorb (210)Po rather than (210)Pb. In combination with particulate composition, (210)Po diffusion was closely related to organic matter. These results reveal that (210)Po might be a potential tracer for quantifying nutrient recycling in the Coral Reef system.

  8. Saproxylic beetles of the Po plain woodlands, Italy

    PubMed Central

    Bogliani, Giuseppe

    2014-01-01

    Abstract Forest ecosystems play an important role for the conservation of biodiversity, and for the protection of ecological processes. The Po plain woodlands which once covered the whole Plain, today are reduced in isolated highly threatened remnants by modern intensive agriculture. These close to natural floodplain forests are one of the most scarce and endangered ecosystems in Europe. Saproxylic species represent a major part of biodiversity of woodlands. The saproxylic insects are considered one of the most reliable bio-indicators of high-quality mature woodlands and have a very important role in regard to the protection and monitoring of forest biodiversity due to their highly specific living environments. As a result of the dramatic reduction of mature forests and the decreased availability of deadwood most of the saproxylic communities are greatly diminishing. The study was conducted in the Ticino Valley Regional Park and the aim is to contribute to the expansion of knowledge on the saproxylic beetles of Lombardy. We investigated 6 sampling sites belonging to alluvial and riparian mixed forests. For each forest we selected 12 trees. For beetles’ collection we used two different traps: Eclector Traps and Trunk Window Traps (total of 72 traps and 864 samples collected). We determined 4.387 beetles from 87 saproxylic species belonging to 21 families. Of these species 51 were not included in the previous checklist of the Park. By comparing the two different techniques used for catching saproxylic beetles, we found a significantly high difference in species richness between Window Traps (WT) and Eclector Traps (ET) with a higher number of species captured in the Window Traps. However, the combined use of two different types of traps significantly expanded the spectrum of insects captured Among the species reported as Least Concern in the IUCN Red List, we found interesting species such as the Elateridae Calambus bipustulats, the Eucnemidae Melasis buprestoides

  9. (Gd,Yb,Tb)PO4 up-conversion nanocrystals for bimodal luminescence-MR imaging

    NASA Astrophysics Data System (ADS)

    Debasu, Mengistie L.; Ananias, Duarte; Pinho, Sonia L. C.; Geraldes, Carlos F. G. C.; Carlos, Luís D.; Rocha, João

    2012-07-01

    Up-conversion (Gd,Yb,Tb)PO4 materials and their potential for bimodal imaging have received little attention in the literature. Herein, we report the first study on the up-conversion emission of (Gd,Yb,Tb)PO4 nanocrystals synthesized via a hydrothermal method at 150 °C. These materials exhibit ultraviolet, blue and green up-conversion emissions upon excitation with a 980 nm continuous wave laser diode. The intensity of the blue-emission band at 479 nm, ascribed to the cooperative up-conversion emission of a pair of excited Yb3+ ions, depends on the Yb3+/Tb3+ concentration ratio, calcination temperature and particle size. Strong green up-conversion emission of Tb3+ is observed at 543 nm for the 5D4 --> 7F5 transition. Relaxometry measurements reveal that the nanocrystals are efficient T2-weighted (negative) contrast agents which, combined with visible-light emission generated by infrared excitation, affords them considerable potential for being used in bimodal, photoluminescence-magnetic resonance, imaging.Up-conversion (Gd,Yb,Tb)PO4 materials and their potential for bimodal imaging have received little attention in the literature. Herein, we report the first study on the up-conversion emission of (Gd,Yb,Tb)PO4 nanocrystals synthesized via a hydrothermal method at 150 °C. These materials exhibit ultraviolet, blue and green up-conversion emissions upon excitation with a 980 nm continuous wave laser diode. The intensity of the blue-emission band at 479 nm, ascribed to the cooperative up-conversion emission of a pair of excited Yb3+ ions, depends on the Yb3+/Tb3+ concentration ratio, calcination temperature and particle size. Strong green up-conversion emission of Tb3+ is observed at 543 nm for the 5D4 --> 7F5 transition. Relaxometry measurements reveal that the nanocrystals are efficient T2-weighted (negative) contrast agents which, combined with visible-light emission generated by infrared excitation, affords them considerable potential for being used in bimodal

  10. Influence of submarine groundwater discharge on (210)Po and (210)Pb bioaccumulation in fish tissues.

    PubMed

    Garcia-Orellana, J; López-Castillo, E; Casacuberta, N; Rodellas, V; Masqué, P; Carmona-Catot, G; Vilarrasa, M; García-Berthou, E

    2016-05-01

    This study presents the results of the accumulation of (210)Po and (210)Pb in fish tissues and organs in a brackish-water marshland that is characterized by high concentrations of (222)Rn and (226)Ra supplied by submarine groundwater discharge (SGD). Tissues and organs from Cyprinus carpio, Chelon labrosus and Carassius auratus in the wetland were significantly enriched by both (210)Pb and (210)Po (up to 55 and 66 times, respectively) compared to blanks. The major input route of (210)Pb and (210)Po into the fish body seems to be through ingestion, due to the high levels of (210)Pb and (210)Po found in the gut content as well as in organs involved in digestion and metabolism (i.e. gut, kidney and hepatopancreas). Results showed that (210)Po was more accumulated in all fish tissues and organs except for the spine, which showed a higher affinity for (210)Pb, due to its capacity to replace Ca from apatite in bones. Over all the variables analyzed, fish tissues/organs and, secondarily, fish species were the most important factors explaining the concentration of radionuclides, whereas fish length and the sampling location played a minor role. The relationship of the two radionuclides varied markedly among tissues and their concentration levels were only correlated in gills, gut and, marginally, in spines. In general, the highest values of (210)Pb and (210)Po concentrations in tissues were found on C. labrosus tissues rather C. auratus and C. carpio. This study demonstrates that inputs of natural radionuclides supplied by SGD to coastal semi-enclosed areas (such as marshlands, lagoons or ponds) may significantly increase the contents of (210)Pb and (210)Po in fish tissues/organs. Thus, this study represents one of the first evidences of direct ecological effects derived from SGD. PMID:26913976

  11. Model analysis of the relationship between intracellular PO2 and energy demand in skeletal muscle.

    PubMed

    Spires, Jessica; Gladden, L Bruce; Grassi, Bruno; Saidel, Gerald M; Lai, Nicola

    2012-12-01

    On the basis of experimental studies, the intracellular O(2) (iPo(2))-work rate (WR) relationship in skeletal muscle is not unique. One study found that iPo(2) reached a plateau at 60% of maximal WR, while another found that iPo(2) decreased linearly at higher WR, inferring capillary permeability-surface area (PS) and blood-tissue O(2) gradient, respectively, as alternative dominant factors for determining O(2) diffusion changes during exercise. This relationship is affected by several factors, including O(2) delivery and oxidative and glycolytic capacities of the muscle. In this study, these factors are examined using a mechanistic, mathematical model to analyze experimental data from contracting skeletal muscle and predict the effects of muscle contraction on O(2) transport, glycogenolysis, and iPo(2). The model describes convection, O(2) diffusion, and cellular metabolism, including anaerobic glycogenolysis. Consequently, the model simulates iPo(2) in response to muscle contraction under a variety of experimental conditions. The model was validated by comparison of simulations of O(2) uptake with corresponding experimental responses of electrically stimulated canine muscle under different O(2) content, blood flow, and contraction intensities. The model allows hypothetical variation of PS, glycogenolytic capacity, and blood flow and predictions of the distinctive effects of these factors on the iPo(2)-contraction intensity relationship in canine muscle. Although PS is the main factor regulating O(2) diffusion rate, model simulations indicate that PS and O(2) gradient have essential roles, depending on the specific conditions. Furthermore, the model predicts that different convection and diffusion patterns and metabolic factors may be responsible for different iPo(2)-WR relationships in humans. PMID:22972834

  12. Dynamic PROOF clusters with PoD: architecture and user experience

    NASA Astrophysics Data System (ADS)

    Manafov, Anar

    2011-12-01

    PROOF on Demand (PoD) is a tool-set, which sets up a PROOF cluster on any resource management system. PoD is a user oriented product with an easy to use GUI and a command-line interface. It is fully automated. No administrative privileges or special knowledge is required to use it. PoD utilizes a plug-in system, to use different job submission front-ends. The current PoD distribution is shipped with LSF, Torque (PBS), Grid Engine, Condor, gLite, and SSH plug-ins. The product is to be extended. We therefore plan to implement a plug-in for AliEn Grid as well. Recently developed algorithms made it possible to efficiently maintain two types of connections: packet-forwarding and native PROOF connections. This helps to properly handle most kinds of workers, with and without firewalls. PoD maintains the PROOF environment automatically and, for example, prevents resource misusage in case when workers idle for too long. As PoD matures as a product and provides more plug-ins, it's used as a standard for setting up dynamic PROOF clusters in many different institutions. The GSI Analysis Facility (GSIAF) is in production since 2007. The static PROOF cluster has been phased out end of 2009. GSIAF is now completely based on PoD. Users create private dynamic PROOF clusters on the general purpose batch farm. This provides an easier resource sharing between interactive local batch and Grid usage. The main user communities are FAIR and ALICE.

  13. Control of the effective P/O ratio of oxidative phosphorylation in liver mitochondria and hepatocytes.

    PubMed Central

    Brand, M D; Harper, M E; Taylor, H C

    1993-01-01

    The control exerted by substrate oxidation reactions, by ATP turnover and by the proton leak over the oxygen consumption rate, the phosphorylation rate, the proton leak rate and the protonmotive force (delta p) in isolated rat liver mitochondria under a range of conditions between non-phosphorylating (State 4) and maximum phosphorylation (State 3) was investigated by using the top-down approach of metabolic control analysis. The experiments were carried out with saturating concentrations of the substrates succinate, glutamate with malate, or pyruvate with malate. The distribution of control was very similar with each of the three substrates. The effective P/O ratio (i.e. not corrected for leak reactions) was also measured; it varied from zero in State 4 to 80-90% of the maximum theoretical P/O ratio in State 3. Under most conditions control over the effective P/O ratio was shared between proton leak (which had negative control) and the phosphorylating subsystem (which had roughly equal positive control); near State 4, substrate oxidation reactions also acquired some control over this ratio. In resting hepatocytes the effective P/O ratio was only 50% of its maximum theoretical value, corresponding to an effective P/O ratio of only 1.3 for complete oxidation of glucose. The effective P/O ratio for intracellular mitochondrial oxygen consumption was 64% of the maximum value. The control coefficient of the mitochondrial proton leak over the effective P/O ratio in cells was -0.34; the control coefficient of phosphorylation reactions over this ratio was 0.31 and the control coefficient of substrate oxidation reactions over the ratio was 0.03, showing how the coupling efficiency in cells can respond sensitively to agents that change the proton leak or the ATP demand, but not to those that change substrate oxidation. PMID:8489502

  14. GaPO4 sensors for gravimetric monitoring during atomic layer deposition at high temperatures.

    PubMed

    Elam, J W; Pellin, M J

    2005-06-01

    The quartz crystal microbalance is extremely useful for in situ monitoring of thin-film growth by atomic layer deposition (ALD) in a viscous flow environment. Unfortunately, conventional AT-quartz sensors are limited to growth temperatures below approximately 300 degrees C. Gallium orthophosphate (GaPO4) is an alternative piezoelectric material offering much greater high-temperature frequency stability than AT-quartz (SiO2). Our measurements reveal that the temperature coefficient for Y-11 degrees GaPO4 decreases linearly with temperature reaching 3 Hz/ degrees C at 450 degrees C. In contrast, the temperature coefficient for the SiO2 sensor increases as the cube of the sensor temperature to 650 Hz/ degrees C at 390 degrees C. To examine the effect of temperature fluctuations on the sensor frequency, we exposed the SiO2 and GaPO4 sensors to helium pulses at 400 degrees C. The resulting frequency change measured for the SiO2 sensor was approximately 40 times greater than that of the GaPO4 sensor. Next, we performed Al2O3 ALD using alternating tri-methylaluminum/water exposures at 400 degrees C and monitored the growth using the SiO2 and GaPO4 sensors. The GaPO4 sensor yielded well-defined pulse shapes in agreement with predictions, while the SiO2 pulses were severely distorted. Measurements during TiO2 ALD using alternating titanium tetrachloride/water exposures at 450 degrees C with the GaPO4 sensor also showed well-defined ALD mass steps.

  15. Development of an Ultra-Pure, Carrier-Free 209Po Solution Standard

    PubMed Central

    Collé, R.; Fitzgerald, R. P.; Laureano-Perez, L.

    2015-01-01

    Ultra-pure, carrier-free 209Po solution standards have been prepared and standardized for their massic alpha-particle emission rate. The standards, which will be disseminated by the National Institute of Standards and Technology (NIST) as Standard Reference Material SRM 4326a, have a mean mass of (5.169 ± 0.003) g of a solution of polonium in nominal 2.0 mol▪L−1 HCl (having a solution density of (1.032 ± 0.002) g▪ mL−1 at 20 °C) that are contained in 5 mL, flame-sealed, borosilicate glass ampoules. They are certified to contain a 209Po massic alpha-particle emission rate of (39.01 ± 0.18) s−1▪g−1 as of a reference time of 1200 EST, 01 December 2013. This new standard series replaces SRM 4326 that was issued by NIST in 1994. The standardization was based on 4πα liquid scintillation (LS) spectrometry with two different LS counting systems and under wide variations in measurement and counting source conditions. The methodology for the standardization, with corrections for detection of the low-energy conversion electrons from the delayed 2 keV isomeric state in 205Pb and for the radiations accompanying the small 0.45 % electron-capture branch to 209Bi, involves a unique spectral analysis procedure that is specific for the case of 209Po decay. The entire measurement protocol is similar, but revised and improved from that used for SRM 4326. Spectroscopic impurity analyses revealed that no photon-emitting or alpha-emitting radionuclidic impurities were detected. The most common impurity associated with 209Po is 208Po and the activity ratio of 208Po/209Po was < 10−7. PMID:26958444

  16. Development of an Ultra-Pure, Carrier-Free (209)Po Solution Standard.

    PubMed

    Collé, R; Fitzgerald, R P; Laureano-Perez, L

    2015-01-01

    Ultra-pure, carrier-free (209)Po solution standards have been prepared and standardized for their massic alpha-particle emission rate. The standards, which will be disseminated by the National Institute of Standards and Technology (NIST) as Standard Reference Material SRM 4326a, have a mean mass of (5.169 ± 0.003) g of a solution of polonium in nominal 2.0 mol▪L(-1) HCl (having a solution density of (1.032 ± 0.002) g▪ mL(-1) at 20 °C) that are contained in 5 mL, flame-sealed, borosilicate glass ampoules. They are certified to contain a (209)Po massic alpha-particle emission rate of (39.01 ± 0.18) s(-1)▪g(-1) as of a reference time of 1200 EST, 01 December 2013. This new standard series replaces SRM 4326 that was issued by NIST in 1994. The standardization was based on 4πα liquid scintillation (LS) spectrometry with two different LS counting systems and under wide variations in measurement and counting source conditions. The methodology for the standardization, with corrections for detection of the low-energy conversion electrons from the delayed 2 keV isomeric state in (205)Pb and for the radiations accompanying the small 0.45 % electron-capture branch to (209)Bi, involves a unique spectral analysis procedure that is specific for the case of (209)Po decay. The entire measurement protocol is similar, but revised and improved from that used for SRM 4326. Spectroscopic impurity analyses revealed that no photon-emitting or alpha-emitting radionuclidic impurities were detected. The most common impurity associated with (209)Po is (208)Po and the activity ratio of (208)Po/(209)Po was < 10(-7). PMID:26958444

  17. Model analysis of the relationship between intracellular Po2 and energy demand in skeletal muscle

    PubMed Central

    Spires, Jessica; Gladden, L. Bruce; Grassi, Bruno; Saidel, Gerald M.

    2012-01-01

    On the basis of experimental studies, the intracellular O2 (iPo2)-work rate (WR) relationship in skeletal muscle is not unique. One study found that iPo2 reached a plateau at 60% of maximal WR, while another found that iPo2 decreased linearly at higher WR, inferring capillary permeability-surface area (PS) and blood-tissue O2 gradient, respectively, as alternative dominant factors for determining O2 diffusion changes during exercise. This relationship is affected by several factors, including O2 delivery and oxidative and glycolytic capacities of the muscle. In this study, these factors are examined using a mechanistic, mathematical model to analyze experimental data from contracting skeletal muscle and predict the effects of muscle contraction on O2 transport, glycogenolysis, and iPo2. The model describes convection, O2 diffusion, and cellular metabolism, including anaerobic glycogenolysis. Consequently, the model simulates iPo2 in response to muscle contraction under a variety of experimental conditions. The model was validated by comparison of simulations of O2 uptake with corresponding experimental responses of electrically stimulated canine muscle under different O2 content, blood flow, and contraction intensities. The model allows hypothetical variation of PS, glycogenolytic capacity, and blood flow and predictions of the distinctive effects of these factors on the iPo2-contraction intensity relationship in canine muscle. Although PS is the main factor regulating O2 diffusion rate, model simulations indicate that PS and O2 gradient have essential roles, depending on the specific conditions. Furthermore, the model predicts that different convection and diffusion patterns and metabolic factors may be responsible for different iPo2-WR relationships in humans. PMID:22972834

  18. Influence of submarine groundwater discharge on (210)Po and (210)Pb bioaccumulation in fish tissues.

    PubMed

    Garcia-Orellana, J; López-Castillo, E; Casacuberta, N; Rodellas, V; Masqué, P; Carmona-Catot, G; Vilarrasa, M; García-Berthou, E

    2016-05-01

    This study presents the results of the accumulation of (210)Po and (210)Pb in fish tissues and organs in a brackish-water marshland that is characterized by high concentrations of (222)Rn and (226)Ra supplied by submarine groundwater discharge (SGD). Tissues and organs from Cyprinus carpio, Chelon labrosus and Carassius auratus in the wetland were significantly enriched by both (210)Pb and (210)Po (up to 55 and 66 times, respectively) compared to blanks. The major input route of (210)Pb and (210)Po into the fish body seems to be through ingestion, due to the high levels of (210)Pb and (210)Po found in the gut content as well as in organs involved in digestion and metabolism (i.e. gut, kidney and hepatopancreas). Results showed that (210)Po was more accumulated in all fish tissues and organs except for the spine, which showed a higher affinity for (210)Pb, due to its capacity to replace Ca from apatite in bones. Over all the variables analyzed, fish tissues/organs and, secondarily, fish species were the most important factors explaining the concentration of radionuclides, whereas fish length and the sampling location played a minor role. The relationship of the two radionuclides varied markedly among tissues and their concentration levels were only correlated in gills, gut and, marginally, in spines. In general, the highest values of (210)Pb and (210)Po concentrations in tissues were found on C. labrosus tissues rather C. auratus and C. carpio. This study demonstrates that inputs of natural radionuclides supplied by SGD to coastal semi-enclosed areas (such as marshlands, lagoons or ponds) may significantly increase the contents of (210)Pb and (210)Po in fish tissues/organs. Thus, this study represents one of the first evidences of direct ecological effects derived from SGD.

  19. GaPO4 sensors for gravimetric monitoring during atomic layer deposition at high temperatures.

    PubMed

    Elam, J W; Pellin, M J

    2005-06-01

    The quartz crystal microbalance is extremely useful for in situ monitoring of thin-film growth by atomic layer deposition (ALD) in a viscous flow environment. Unfortunately, conventional AT-quartz sensors are limited to growth temperatures below approximately 300 degrees C. Gallium orthophosphate (GaPO4) is an alternative piezoelectric material offering much greater high-temperature frequency stability than AT-quartz (SiO2). Our measurements reveal that the temperature coefficient for Y-11 degrees GaPO4 decreases linearly with temperature reaching 3 Hz/ degrees C at 450 degrees C. In contrast, the temperature coefficient for the SiO2 sensor increases as the cube of the sensor temperature to 650 Hz/ degrees C at 390 degrees C. To examine the effect of temperature fluctuations on the sensor frequency, we exposed the SiO2 and GaPO4 sensors to helium pulses at 400 degrees C. The resulting frequency change measured for the SiO2 sensor was approximately 40 times greater than that of the GaPO4 sensor. Next, we performed Al2O3 ALD using alternating tri-methylaluminum/water exposures at 400 degrees C and monitored the growth using the SiO2 and GaPO4 sensors. The GaPO4 sensor yielded well-defined pulse shapes in agreement with predictions, while the SiO2 pulses were severely distorted. Measurements during TiO2 ALD using alternating titanium tetrachloride/water exposures at 450 degrees C with the GaPO4 sensor also showed well-defined ALD mass steps. PMID:15924385

  20. Structure determination and optical properties of CsSm(PO{sub 3}){sub 4}

    SciTech Connect

    Ben Hassen, N.; Ferhi, M. Horchani-Naifer, K.; Férid, M.

    2015-03-15

    Graphical abstract: Projection of the CsSm(PO{sub 3}){sub 4} structure viewing along the a axis. - Highlights: • Single crystal of a new polyphosphate CsSm(PO{sub 3}){sub 4} has been synthesized. • The obtained compound has been characterized by several techniques. • The crystal structure of CsSm(PO{sub 3}){sub 4} has been resolved. • Spectroscopic properties of Sm{sup 3+} in CsSm(PO{sub 3}){sub 4} have been performed. - Abstract: A new alkali metal-rare earth polyphosphate CsSm(PO{sub 3}){sub 4} has been synthesized by flux method. The obtained compound has been characterized by means of single crystal X-ray diffraction, Fourier transform infrared (FTIR) and Raman scattering spectroscopies. It crystallizes in the monoclinic space group P2{sub 1}/n with the following unit-cell parameters: a = 10.382(2), b = 8.978(6), c = 11.205(4) Å, β = 106.398(3)° and Z = 4. The structure of CsSm(PO{sub 3}){sub 4} is an infinite three-dimensional framework made up of double spiral (PO{sub 3}){sub n} chains linked with neighboring SmO{sub 8} and CsO{sub 11} polyhedra. Spectroscopic properties of Sm{sup 3+} in this new compound including excitation, emission, and kinetic measurement have been performed. The emission spectrum shows four transitions characteristics of Sm{sup 3+} in the orange–red region by excitation wavelength at 400 nm. The decay time curve of {sup 4}G{sub 5/2} → {sup 6}H{sub 7/2} transition has been also registered and fitted to a single exponential function.

  1. The influence of temperature on a nutty-cake structural material: LiMn1-xFexPO4 composite with LiFePO4 core and carbon outer layer for lithium-ion battery

    NASA Astrophysics Data System (ADS)

    Huo, Zhen-Qing; Cui, Yu-Ting; Wang, Dan; Dong, Yue; Chen, Li

    2014-01-01

    The extremely low electronic conductivity, slow ion diffusion kinetics, and the Jahn-Teller effect of LiMnPO4 limit its electrochemical performance. In this work, a nutty-cake structural C-LiMn1-xFexPO4-LiFePO4 cathode material is synthesized by hydrothermal method and further calcined at different temperatures. The influence of calcination temperature on the electrochemical behavior is investigated by X-ray diffractometer, scanning electron microscope, field-emission high-resolution transmission electron microscope, energy-dispersive X-ray spectroscopy, electrochemical impedance spectroscopy and charge-discharge tests. And the performance of C-LiMn1-xFexPO4-LiFePO4 materials has a relationship with its crystal structure. The well-crystallized Sample-600 calcined at 600 °C shows the smallest charge transfer resistance, the largest lithium ion diffusion coefficient (DLi) and the best cycling stability. The discharge capacity of Sample-600 holds around 112 mAh g-1 after the 3rd cycle at 0.1 C rate. The performances improvement of C-LiMn1-xFexPO4-LiFePO4 material can be mainly attributed to the iron diffusion from the LiFePO4 core to the outer LiMnPO4 layer under appropriate calcination temperature.

  2. Critical O2 delivery to skeletal muscle at high and low PO2 in endotoxemic dogs.

    PubMed

    Bredle, D L; Samsel, R W; Schumacker, P T; Cain, S M

    1989-06-01

    An ischemic canine limb model was used to determine whether endotoxin reduces the ability of resting skeletal muscle to extract O2 and whether increasing the arterial PO2 would increase its O2 extraction. Isolated limbs were pump perfused via an extracorporeal circuit with membrane oxygenator at three progressively lower flows and PO2 of both 60 and 200 Torr, whereas the rest of the body remained normoxic and normotensive. Six anesthetized, paralyzed dogs were injected with endotoxin (4 mg/kg, ENDO), and another six were controls (CONT). Limb critical O2 delivery was higher (P less than 0.05) in ENDO than CONT (8.3 vs. 6.1 ml.kg-1.min-1). Critical venous PO2 was also higher (P less than 0.05) in ENDO than CONT (38 vs. 30 Torr). Critical O2 extraction ratio was lower (P less than 0.05) in ENDO than CONT (0.60 vs. 0.73). There were no differences in these variables between low and high arterial PO2. We concluded that 1) endotoxin can cause a small but significant O2 extraction defect in skeletal muscle, 2) increasing arterial PO2 did not correct such a defect, nor did it improve O2 uptake in ischemic, but otherwise healthy, muscle, and 3) skeletal muscle may contribute to the peripheral O2 extraction defect in adult respiratory distress syndrome insofar as endotoxin effects model those found in adult respiratory distress syndrome.

  3. Coating the Conductivity Materials to Improving the Electrochemical Properties of LiFePO4

    NASA Astrophysics Data System (ADS)

    Wang, Wan Lin; Jin, En Mei; Gu, Hal-Bon

    2013-03-01

    LiFePO4 cathode materials were prepared by a solid-state method followed by one-step heat treatment. To improve the electrochemical properties of the LiFePO4, acetylene black (AB), citric acid (CA), and pyrene are added as carbon source, respectively. The cyclic voltammetry (CV), AC impedance and galvanostatic charge/discharge testing results showed that using the LiFePO4-C composite such as the AB carbon source exhibits higher discharge capacity and stability than the other composite. Synthesized LiFePO4-C/Li cells (with AB) showed that initial discharge capacity was 140.65 mA h g-1 and at the 2nd cycle were 145.87 mA h g-1, respectively. Morphology and electrochemical performance of the LiFePO4 cathode materials were investigated. Furthermore, the cell was subjected to current density studies (0.1 mA cm-2) that suggested excellent capacity retention of the cell at 25°C.

  4. Scientist-Educator Partnerships: the Cornerstone of Astrophysics E/PO

    NASA Astrophysics Data System (ADS)

    Meinke, Bonnie K.; Smith, Denise A.; Lawton, Brandon; Eisenhamer, Bonnie; Jirdeh, Hussein

    2015-11-01

    For nearly two decades, NASA has partnered scientists and educators by embedding Education and Public Outreach (E/PO) programs and funding in its science missions and research activities. This enables scientist and educators to work side-by-side in translating cutting-edge NASA science and technology for classrooms, museums, and public venues.The Office of Public Outreach at the Space Telescope Science Institute (STScI) is uniquely poised to foster collaboration between scientists with content expertise and educators with pedagogy expertise. As home to both Hubble Space Telescope and the future James Webb Space Telescope, STScI leverages the expertise of its scientists to create partnerships with its collocated Education Team to translate cutting-edge NASA science into new and effective learning tools. In addition, STScI is home of the NASA Science Mission Directorate (SMD) Astrophysics Science E/PO Forum, which facilitates connections both within the SMD E/PO community and beyond to scientists and educators across all NASA Astrophysics missions. These collaborations strengthen partnerships, build best practices, and enhance coherence for NASA SMD-funded E/PO missions and programs.We will present examples of astronomers’ engagement in our E/PO efforts, such as NASA Science4Girls.

  5. Advanced carbon materials/olivine LiFePO4 composites cathode for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Gong, Chunli; Xue, Zhigang; Wen, Sheng; Ye, Yunsheng; Xie, Xiaolin

    2016-06-01

    In the past two decades, LiFePO4 has undoubtly become a competitive candidate for the cathode material of the next-generation LIBs due to its abundant resources, low toxicity and excellent thermal stability, etc. However, the poor electronic conductivity as well as low lithium ion diffusion rate are the two major drawbacks for the commercial applications of LiFePO4 especially in the power energy field. The introduction of highly graphitized advanced carbon materials, which also possess high electronic conductivity, superior specific surface area and excellent structural stability, into LiFePO4 offers a better way to resolve the issue of limited rate performance caused by the two obstacles when compared with traditional carbon materials. In this review, we focus on advanced carbon materials such as one-dimensional (1D) carbon (carbon nanotubes and carbon fibers), two-dimensional (2D) carbon (graphene, graphene oxide and reduced graphene oxide) and three-dimensional (3D) carbon (carbon nanotubes array and 3D graphene skeleton), modified LiFePO4 for high power lithium ion batteries. The preparation strategies, structure, and electrochemical performance of advanced carbon/LiFePO4 composite are summarized and discussed in detail. The problems encountered in its application and the future development of this composite are also discussed.

  6. Diurnal variations of (218)Po, (214)Pb, and (214)Po and their effect on atmospheric electrical conductivity in the lower atmosphere at Mysore city, Karnataka State, India.

    PubMed

    Pruthvi Rani, K S; Paramesh, L; Chandrashekara, M S

    2014-12-01

    The short-lived radon daughters ((218)Po, (214)Pb, (214)Bi and (214)Po) are natural tracers in the troposphere, in particular near the ground surface. They are electrically charged particles and are chemically reactive. As soon as they are formed they get attached to the aerosol particles of the atmosphere. The behavior of radon daughters is similar to that of aerosols with respect to their growth, transport and removal processes in the atmosphere. The electrical conductivity of the atmosphere is mainly due to the presence of highly mobile ions. Galactic cosmic rays are the main source of ionization in the planetary boundary layer; however, near the surface of the earth, ions are produced mainly by decays of natural radioactive gases emanating from the soil surface and by radiations emitted directly from the surface. Hence the electrical conductivity of air near the surface of the earth is mainly due to radiations emitted by (222)Rn, (218)Po, (214)Pb, (214)Bi and (214)Po, and depends on aerosol concentrations and meteorological parameters. In the present work the diurnal and seasonal variations of radon and its progeny concentrations are studied using Low Level Radon Detection System and Airflow Meter respectively. Atmospheric electrical conductivity of both positive and negative polarities is measured using a Gerdien Condenser. All the measurements were carried out simultaneously at one location in Mysore city (12°N, 76°E), India. The diurnal variation of atmospheric electrical conductivity was found to be similar to that of ion pair production rate estimated from radon and its progeny concentrations with a maximum in the early morning hours and minimum during day time. The annual average concentrations of (222)Rn, (218)Po, (214)Pb, and (214)Po at the study location were found to be 21.46, 10.88, 1.78 and 1.80 Bq m(-3) respectively. The annual average values of positive and negative atmospheric electrical conductivity were found to be 18.1 and 16.6 f S m(-1

  7. Diurnal variations of (218)Po, (214)Pb, and (214)Po and their effect on atmospheric electrical conductivity in the lower atmosphere at Mysore city, Karnataka State, India.

    PubMed

    Pruthvi Rani, K S; Paramesh, L; Chandrashekara, M S

    2014-12-01

    The short-lived radon daughters ((218)Po, (214)Pb, (214)Bi and (214)Po) are natural tracers in the troposphere, in particular near the ground surface. They are electrically charged particles and are chemically reactive. As soon as they are formed they get attached to the aerosol particles of the atmosphere. The behavior of radon daughters is similar to that of aerosols with respect to their growth, transport and removal processes in the atmosphere. The electrical conductivity of the atmosphere is mainly due to the presence of highly mobile ions. Galactic cosmic rays are the main source of ionization in the planetary boundary layer; however, near the surface of the earth, ions are produced mainly by decays of natural radioactive gases emanating from the soil surface and by radiations emitted directly from the surface. Hence the electrical conductivity of air near the surface of the earth is mainly due to radiations emitted by (222)Rn, (218)Po, (214)Pb, (214)Bi and (214)Po, and depends on aerosol concentrations and meteorological parameters. In the present work the diurnal and seasonal variations of radon and its progeny concentrations are studied using Low Level Radon Detection System and Airflow Meter respectively. Atmospheric electrical conductivity of both positive and negative polarities is measured using a Gerdien Condenser. All the measurements were carried out simultaneously at one location in Mysore city (12°N, 76°E), India. The diurnal variation of atmospheric electrical conductivity was found to be similar to that of ion pair production rate estimated from radon and its progeny concentrations with a maximum in the early morning hours and minimum during day time. The annual average concentrations of (222)Rn, (218)Po, (214)Pb, and (214)Po at the study location were found to be 21.46, 10.88, 1.78 and 1.80 Bq m(-3) respectively. The annual average values of positive and negative atmospheric electrical conductivity were found to be 18.1 and 16.6 f S m(-1

  8. Magnetic structures of NaFePO4 maricite and triphylite polymorphs for sodium-ion batteries.

    PubMed

    Avdeev, Maxim; Mohamed, Zakiah; Ling, Chris D; Lu, Jiechen; Tamaru, Mao; Yamada, Atsuo; Barpanda, Prabeer

    2013-08-01

    The magnetic structure and properties of polycrystalline NaFePO4 polymorphs, maricite and triphylite, both derived from the olivine structure type, have been investigated using magnetic susceptibility, heat capacity, and low-temperature neutron powder diffraction. These NaFePO4 polymorphs assume orthorhombic frameworks (space group No. 62, Pnma), built from FeO6 octahedral and PO4 tetrahedral units having corner-sharing and edge-sharing arrangements. Both polymorphs demonstrate antiferromagnetic ordering below 13 K for maricite and 50 K for triphylite. The magnetic structure and properties are discussed considering super- and supersuperexchange interactions in comparison to those of triphylite-LiFePO4.

  9. Linker length and flexibility induces new cellobiohydrolase activity of PoCel6A from Penicillium oxalicum.

    PubMed

    Gao, Le; Wang, Lushan; Jiang, Xukai; Qu, Yinbo

    2015-06-01

    In a previous study, a novel cellobiohydrolase, PoCel6A, with new enzymatic activity against p-nitrophenyl-β-D-cellobioside (pNPC), was purified from Penicillium oxalicum. The cellulose-binding module and catalytic domain of PoCel6A showed a high degree of sequence similarity with other fungal Cel6As. However, PoCel6A had 11 more amino acids in the linker region than other Cel6As. To evaluate the relationship between the longer linker of PoCel6A and its enzymatic activity, 11 amino acids were deleted from the linker region of PoCel6A. The shortened PoCel6A linker nullified the enzymatic activity against pNPC but dramatically increased the enzyme's capacity for crystalline cellulose degradation. The shortened linker segment appeared to have no effect on the secondary structural conformation of PoCel6A. Another variant (PoCel6A-6pro) with six consecutive proline residues in the interdomain linker had a higher rigid linker, and no enzymatic activity was observed against soluble and insoluble substrate. The flexibility of the linker had an important function in the formation of active cellulase. The length and flexibility of the linker is clearly able to modify the function of PoCel6A and induce new characteristics of Cel6A.

  10. Linker length and flexibility induces new cellobiohydrolase activity of PoCel6A from Penicillium oxalicum.

    PubMed

    Gao, Le; Wang, Lushan; Jiang, Xukai; Qu, Yinbo

    2015-06-01

    In a previous study, a novel cellobiohydrolase, PoCel6A, with new enzymatic activity against p-nitrophenyl-β-D-cellobioside (pNPC), was purified from Penicillium oxalicum. The cellulose-binding module and catalytic domain of PoCel6A showed a high degree of sequence similarity with other fungal Cel6As. However, PoCel6A had 11 more amino acids in the linker region than other Cel6As. To evaluate the relationship between the longer linker of PoCel6A and its enzymatic activity, 11 amino acids were deleted from the linker region of PoCel6A. The shortened PoCel6A linker nullified the enzymatic activity against pNPC but dramatically increased the enzyme's capacity for crystalline cellulose degradation. The shortened linker segment appeared to have no effect on the secondary structural conformation of PoCel6A. Another variant (PoCel6A-6pro) with six consecutive proline residues in the interdomain linker had a higher rigid linker, and no enzymatic activity was observed against soluble and insoluble substrate. The flexibility of the linker had an important function in the formation of active cellulase. The length and flexibility of the linker is clearly able to modify the function of PoCel6A and induce new characteristics of Cel6A. PMID:25866282

  11. Accumulation of polonium 210Po in tissues and organs of deer carvidae from Northern Poland.

    PubMed

    Skwarzec, Bogdan; Prucnal, Malgorzata

    2007-01-01

    This study was undertaken to provide information on accumulation of polonium in tissues and organs of deer carvidae in order to assess the potential transport of this element via food-chain to game meat consumers. Livers, kidneys and muscles of large herbivorous animals belonging to three species: roe deer (Capreolus capreolus), red deer (Cervus elaphus) and fallow deer (Dama dama), collected in Northern Poland, were the subject of the present investigation. Activities of (210)Po were determined by means of alpha spectrometry along with relevant radiochemical procedures. The concentration of (210)Po in analyzed animals decreased in the order kidney > liver > muscle tissue. The average activity concentrations of (210)Po ranged between 0.02 +/- 0.01 Bq. kg(- 1) w.w. in muscles and 7.15 +/- 0.12 Bq. kg(- 1) w.w. in kidneys. Levels of polonium were not influenced by sampling location, sex, age and species of animals.

  12. Bioaccumulation of 210Po in common gastropod and bivalve species from the northern Gulf.

    PubMed

    Uddin, S; Bebhehani, M

    2014-06-01

    This study sets the baseline for the concentration of the natural-series radionuclide polonium-210 in two species of gastropods and four species of bivalves that are common to the Northern Arabian/Persian Gulf. (210)Po is primarily absorbed from water and via ingestion of detrital material by gastropoda and bivalves. This concentrated (210)Po can then be passed along to the next trophic level of the marine food web. The lowest (210)Po concentration was measured in the gastropod Stomatella auricular (10.36-12.39Bq kg(-1)dry) and the highest in the bivalve Marica marmorata (193.51-215.60Bq kg(-1)dry). The measured concentration factor for these molluscs in the northern Gulf varied between 4.8 and 115×10(3), values very similar to the IAEA recommended value for bivalves and gastropods of 2×10(4).

  13. Determination of (210)Pb and (210)Po in water using the extractive scintillation cocktail Polex™.

    PubMed

    Landstetter, Claudia; Hiegesberger, Bernd; Sinojmeri, Merita; Katzlberger, Christian

    2014-11-01

    Method validation was performed to achieve the accreditation for our determination method of (210)Pb and (210)Po in water. A Pb(NO3)2 carrier is added to the sample and lead is precipitated with Na2SxH2O. (210)Po is co-precipitated and the extractive scintillation cocktail Polex(™) is used to determine (210)Po and (210)Pb. Uranium is also extracted by Polex(™). It can be removed by washing the precipitate with 1% HNO3. The ingrowth of (210)Pb from (222)Rn during transportation time must be calculated. It has to be subtracted from the original (210)Pb in the sample and taken into account for the calculation of the lower limit of detection.

  14. Ab initio study of pressure induced structural and electronic properties in TmPo

    SciTech Connect

    Makode, Chandrabhan Pataiya, Jagdish; Sanyal, Sankar P.; Panwar, Y. S.; Aynyas, Mahendra

    2015-06-24

    We report an ab initio calculation of pressure induced structural phase transition and electronic properties of Thulium Polonide (TmPo).The total energy as a function of volume is obtained by means of self-consistent tight binding linear muffin-tin-orbital (TB-LMTO) method within the local density approximation (LDA). It is found that TmPo is stable in NaCl-type (B{sub 1}-phase) structure to CsCl-type (B{sub 2}-phase) structure of this compound in the pressure range of 7.0 GPa. We also calculate the lattice parameter (a{sub 0}), bulk modulus (B{sub 0}), band structure and density of states. From energy diagram it is observed that TmPo exhibit metallic behavior. The calculated values of equilibrium lattice parameter and bulk modulus are in general good agreement.

  15. Yellow-emitting NaCaPO4:Mn2+ phosphor for field emission displays

    NASA Astrophysics Data System (ADS)

    Li, Guogang; Xu, Xingong; Peng, Chong; Shang, Mengmeng; Geng, Dongling; Cheng, Ziyong; Chen, Jun; Lin, Jun

    2011-08-01

    Yellow-emitting NaCaPO4:Mn2+ phosphors were prepared by the Pechini sol-gel process. Under low voltage electron beam excitation, the NaCaPO4: Mn2+ phosphor screen shows bright yellow emission (centering at 560 nm due to the 4T1→6A1 transition of Mn2+) with the CIE color coordinate (0.428, 0.552), which has a higher color purity than commercial yellow-emitting FED phosphor (Zn, CdS):Ag+. The color range and chromaticity saturation may be greatly enhanced when the yellow-emitting NaCaPO4: Mn2+ is added as an additional phosphor of the typical tricolor FEDs phosphors, which make them have potential to improve the display quality of full-color FEDs.

  16. (210)Po and (210)Pb in medicinal plants in the region of Karnataka, Southern India.

    PubMed

    Chandrashekara, K; Somashekarappa, H M

    2016-08-01

    The activity concentrations of naturally occurring radionuclides (210)Po and (210)Pb were estimated in some selected medicinal plants and soil samples of coastal Karnataka in India. The mean activity concentrations of (210)Po and (210)Pb varied in the range of 4.7-42.9 Bq kg(-1) (dry weight) and 36.1-124 Bq kg(-1) (dry weight) in the soil samples, and 3.3-63.7 Bq kg(-1) (dry weight) and 12.0-406 Bq kg(-1) (dry weight), in the medicinal plant samples, respectively. The plants, Ocimum sanctum L. and Plectranthus amboinicus (Lour.) Spreng had significantly higher activity concentrations of (210)Po and (210)Pb than other species sampled. In spite of disequilibrium between them, these two radionuclides were well correlated in both soil and medicinal plants. PMID:27155527

  17. CIGS solar cell devices on steel substrates coated with Na containing AlPO4

    NASA Astrophysics Data System (ADS)

    Kim, Moojin; Kim, Kyoung-Bo; Jeon, Chan-Wook; Lee, Dongyun; Lee, Sung-Nam; Lee, Ji-Myon; Lee, Hong-Chan

    2015-11-01

    Flexible copper indium gallium diselenide (CIGS)-based solar cells are developed on stainless steel (STS) substrates covered with an insulating layer. The Na containing AlPO4 ("Na-AlPO4") material is processed using the slot-die coating method. The coated film is analyzed using various spectroscopic methods including scanning electron microscopy, energy dispersive X-ray spectrometry, transmission electron microscopy, secondary-ion mass spectrometry, X-ray diffraction, and 3D profiler. The characteristics of the solar cells fabricated on these insulating films are also evaluated. The application of the Na-AlPO4 layer on the STS substrates is compared with the electrical performance of the CIGS solar cells fabricated on metal foil. Although the insertion of the insulating layer does not influence the formation of the CIGS film and solar cell performance, a better uniformity in the current-voltage curve is obtained.

  18. LiFePO{sub 4}/gel/natural graphite cells for the BATT program

    SciTech Connect

    Striebel, K.; Guerfi, A.; Shim, J.; Armand, M.; Gauthier, M.; Zaghib, K.

    2002-10-29

    LiFePO{sub 4}/gel/natural graphite (NG) cells have been prepared and cycled under a fixed protocol for cycle and calendar life determination. Cell compression of 10 psi was found to represent an optimal balance between cell impedance and the first cycle losses on the individual electrodes with the gel electrolyte. Cells with a Li anode showed capacities of 160 and 78 mAh/g-LiFePO{sub 4} for C/25 and 2C discharge rates, respectively. Rapid capacity and power fade were observed in the LiFePO{sub 4}/gel/NG cells during cycling and calendar life studies. Diagnostic evaluations point to the consumption of cycleable Li though a side reaction as the reason for performance fade with minimal degradation of the individual electrodes.

  19. NaCo(H2PO2)3: Crystal structure and physical study

    NASA Astrophysics Data System (ADS)

    El Bali, Brahim; Lachkar, Mohammed; Essehli, Rachid; Dusek, Michal; Rohlicek, Jan; Mircescu, Nicoleta; Haisch, Christoph

    2016-11-01

    NaCo(H2PO2)3 was synthesized in solution and its structure was studied by single-crystal X-ray diffraction. It crystallizes in the cubic space group P213 (#198), Z = 4, a = 9.2563(16) Å, V = 793.1(2) Å3. Final residual factors of the refined structure model R/Rw were 0.0367/0.0941. The cations Na+ and Co2+ are both octahedrally coordinated. [NaO6] and [CoO6] share edges to form channels propagating along [1,-1, -1] with the [H2PO2] pseudo-pyramids adjusted inside the channels to the above mentioned octahedra. The IR and Raman spectroscopic studies show the expected bands of the hypophosphite anion. NaCo(H2PO2)3 did not show any electrochemical activity under the electrochemical test conditions (2.4-4.5 V vs. Na/Na+).

  20. The disequilibrium between 210Po and 210Pb in raw and drinking waters.

    PubMed

    Idoeta, R; Herranz, M; Legarda, F

    2011-01-01

    Many countries have to monitor and control the radioactivity in drinking waters in order to ensure compliance with the requirements of their respective regulations. Among radionuclides responsible for this radioactivity there are (210)Po and (210)Pb, which are usually not in radioactive equilibrium in waters. This paper deals with the analysis of this disequilibrium and the way that the water treatment plants affect it. To do this, (210)Po and (210)Pb activity concentrations were measured in raw and drinking water. The measurements were performed by alpha-particle spectrometry and gas flow proportional counting and the corresponding formulae for uncertainties and detection limits are presented. The values obtained show that the Po/Pb ratio is lower in surface than in ground waters. Regarding water treatment, this ratio adopts values lower in drinking water than in raw waters. In any case, for the waters analysed in this work the committed effective doses due to these radionuclides, are negligible.

  1. Bioaccumulation of 210Po in common gastropod and bivalve species from the northern Gulf.

    PubMed

    Uddin, S; Bebhehani, M

    2014-06-01

    This study sets the baseline for the concentration of the natural-series radionuclide polonium-210 in two species of gastropods and four species of bivalves that are common to the Northern Arabian/Persian Gulf. (210)Po is primarily absorbed from water and via ingestion of detrital material by gastropoda and bivalves. This concentrated (210)Po can then be passed along to the next trophic level of the marine food web. The lowest (210)Po concentration was measured in the gastropod Stomatella auricular (10.36-12.39Bq kg(-1)dry) and the highest in the bivalve Marica marmorata (193.51-215.60Bq kg(-1)dry). The measured concentration factor for these molluscs in the northern Gulf varied between 4.8 and 115×10(3), values very similar to the IAEA recommended value for bivalves and gastropods of 2×10(4). PMID:24675441

  2. Determination of (210)Pb and (210)Po in water using the extractive scintillation cocktail Polex™.

    PubMed

    Landstetter, Claudia; Hiegesberger, Bernd; Sinojmeri, Merita; Katzlberger, Christian

    2014-11-01

    Method validation was performed to achieve the accreditation for our determination method of (210)Pb and (210)Po in water. A Pb(NO3)2 carrier is added to the sample and lead is precipitated with Na2SxH2O. (210)Po is co-precipitated and the extractive scintillation cocktail Polex(™) is used to determine (210)Po and (210)Pb. Uranium is also extracted by Polex(™). It can be removed by washing the precipitate with 1% HNO3. The ingrowth of (210)Pb from (222)Rn during transportation time must be calculated. It has to be subtracted from the original (210)Pb in the sample and taken into account for the calculation of the lower limit of detection. PMID:24816175

  3. Chemotransduction in the Carotid Body: K+ Current Modulated by Po2 in Type I Chemoreceptor Cells

    NASA Astrophysics Data System (ADS)

    Lopez-Barneo, Jose; Lopez-Lopez, Jose R.; Urena, Juan; Gonzalez, Constancio

    1988-07-01

    The ionic currents of carotid body type I cells and their possible involvement in the detection of oxygen tension (Po2) in arterial blood are unknown. The electrical properties of these cells were studied with the whole-cell patch clamp technique, and the hypothesis that ionic conductances can be altered by changes in Po2 was tested. The results show that type I cells have voltage-dependent sodium, calcium, and potassium channels. Sodium and calcium currents were unaffected by a decrease in Po2 from 150 to 10 millimeters of mercury, whereas, with the same experimental protocol, potassium currents were reversibly reduced by 25 to 50 percent. The effect of hypoxia was independent of internal adenosine triphosphate and calcium. Thus, ionic conductances, and particularly the O2-sensitive potassium current, play a key role in the transduction mechanism of arterial chemoreceptors.

  4. Na7Cr4(P2O7)4PO4

    PubMed Central

    Bourguiba Fakhar, Noura; Zid, Mohamed Faouzi; Driss, Ahmed

    2013-01-01

    The title compound, hepta­sodium tetra­chromium(III) tetra­kis­(diphosphate) orthophosphate, was synthesized by solid-state reaction. Its structure is isotypic with that of Na7 M 4(P2O7)4PO4 (M = In, Al) compounds and is made up from a three-dimensional [(CrP2O7)4PO4]7− framework with channels running along [001]. The three Na+ cations are located in the voids of the framework. One of the cations is situated on a general position, one is equally disordered around a twofold rotation axis and one is on a fourfold rotoinversion axis. The isolated PO4 tetra­hedron of the anionic framework is also situated on the -4 axis. Structural relationships between the title compound and different diphosphates containing MP2O11 units (M = Mo, V) are discussed. PMID:23723751

  5. Thermoluminescence and photoluminescence in the NaCaPO4:Dy3+ phosphor.

    PubMed

    Shinde, K N; Dhoble, S J

    2012-12-01

    Dy(3+)-doped NaCaPO(4) phosphor was synthesised at an initiating combustion temperature of 600°C, using urea as the fuel. The crystallinity of the phosphor was investigated by using X-ray diffraction. The photoluminescence and thermoluminescence (TL) behaviours of NaCaPO(4):Dy(3+) phosphor was also studied. It has a simple TL glow curve structure, which does not change when exposed to gamma-rays. A TL glow peak is observed at 230°C and TL intensity is around 1.15 times more compared with commercial CaSO(4):Dy TLD phosphor. The TL characteristics of the phosphor prepared show that it has good sensitivity, linear response with gamma-rays exposure, emission in the blue-yellow regions of the spectrum, negligible fading and excellent reusability. These results make Dy(3+)-doped NaCaPO(4) phosphor attractive for TLD applications.

  6. Synthesis and luminescence properties of KSrPO4:Eu2+ phosphor for radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Palan, C. B.; Bajaj, N. S.; Omanwar, S. K.

    2016-05-01

    The KSrPO4:Eu phosphor was synthesized via solid state method. The structural and morphological characterizations were done through XRD (X-ray diffraction) and SEM (Scanning Electronic Microscope). Additionally, the photoluminescence (PL), thermoluminescence (TL) and optically Stimulated luminescence (OSL) properties of powder KSrPO4:Eu were studied. The PL spectra show blue emission under near UV excitation. It was advocated that KSrPO4:Eu phosphor not only show OSL sensitivity (0.47 times) but also gives faster decay in OSL signals than that of Al2O3:C (BARC) phosphor. The TL glow curve consist of two shoulder peaks and the kinetics parameters such as activation energy and frequency factors were determined by using peak shape method and also photoionization cross-sections of prepared phosphor was calculated. The radiation dosimetry properties such as minimum detectable dose (MDD), dose response and reusability were reported.

  7. Synthesis and characterization of LiFePO4 cathode preparation by low temperature method

    NASA Astrophysics Data System (ADS)

    Rajesh, Desapogu; Srinivas Naik, V.; Sunandana, C. S.

    2015-05-01

    We review in detail the physics and technology of the novel material LiFePO4, a potential cathode material for Li-ion batteries. In the present work, nano crystalline LiFePO4 film has been synthesized in both powder and thin film forms from a non-aqueous sol-gel synthesis route based on oxalates of Li and Fe (II). Ferrous oxalate has been synthesized indigenously using a ferrous sulphate based chemical reaction and characterized. Nano powders and thin films of LiFePO4 have been fabricated and coated on stainless steel substrates with the aim of device development in future. The material has been characterized extensively by XRD for crystal structure, FESEM for microstructure, EDS for elemental analysis and FTIR for the internal modes of phosphate ion. Fe3+ impurity characterization has been done by using ESR.

  8. C3PO, an endoribonuclease that promotes RNAi by facilitating RISC activation.

    PubMed

    Liu, Ying; Ye, Xuecheng; Jiang, Feng; Liang, Chunyang; Chen, Dongmei; Peng, Junmin; Kinch, Lisa N; Grishin, Nick V; Liu, Qinghua

    2009-08-01

    The catalytic engine of RNA interference (RNAi) is the RNA-induced silencing complex (RISC), wherein the endoribonuclease Argonaute and single-stranded small interfering RNA (siRNA) direct target mRNA cleavage. We reconstituted long double-stranded RNA- and duplex siRNA-initiated RISC activities with the use of recombinant Drosophila Dicer-2, R2D2, and Ago2 proteins. We used this core reconstitution system to purify an RNAi regulator that we term C3PO (component 3 promoter of RISC), a complex of Translin and Trax. C3PO is a Mg2+-dependent endoribonuclease that promotes RISC activation by removing siRNA passenger strand cleavage products. These studies establish an in vitro RNAi reconstitution system and identify C3PO as a key activator of the core RNAi machinery.

  9. Synthesis, characterization and optical properties of NH4Dy(PO3)4

    NASA Astrophysics Data System (ADS)

    Chemingui, S.; Ferhi, M.; Horchani-Naifer, K.; Férid, M.

    2014-09-01

    Polycrystalline powders of NH4Dy(PO3)4 polyphosphate have been grown by the flux method. This compound was found to be isotopic with NH4Ce(PO3)4 and RbHo(PO3)4. It crystallizes in the monoclinic space group P21/n with unit cell parameters a=10.474(6) Å, b=9.011(4) Å, c=10.947(7) Å and β=106.64(3)°. The title compound has been transformed to triphosphate Dy(PO3)3 after calcination at 800 °C. Powder X-ray diffraction, infrared and Raman spectroscopies and the differential thermal analysis have been used to identify these materials. The spectroscopic properties have been investigated through absorption, excitation, emission spectra and decay curves of Dy3+ ion in both compounds at room temperature. The emission spectra show the characteristic emission bands of Dy3+ in the two compounds, before and after calcination. The integrated emission intensity ratios of the yellow to blue (IY/IB) transitions and the chromaticity properties have been determined from emission spectra. The decay curves are found to be double-exponential. The non-exponential behavior of the decay rates was related to the resonant energy transfer as well as cross-relaxation between the donor and acceptor Dy3+ ions. The determined properties have been discussed as function of crystal structure of both compounds. They reveal that NH4Dy(PO3)4 is promising for white light generation but Dy(PO3)3 is potential candidates in field emission display (FED) and plasma display panel (PDP) devices.

  10. Retrospective assessment of indoor radon exposure by measurements of embedded 210Po activity in glass objects

    NASA Astrophysics Data System (ADS)

    Ramola, R. C.; Gusain, G. S.; Prasad, Ganesh

    In most of the epidemiological studies contemporary radon measurements have been used as surrogates for radon concentrations in past decades even though changes in radon levels and residence may have occurred. Short-lived radon progeny may deposit on available surfaces in dwellings thus giving rise over time to a build up of long-lived progeny. Airborne radon decay products can be deposited and implanted through alpha recoil into the glass surfaces. On glass surface, activities of 210Po may arise as a result of the decay of recoil implanted activity following the alpha decay of surface deposited 218Po or 214Po. Measurement of 210Po implanted on a household glass is a method that can be employed to retrospectively determine the historic level of radon in dwellings. This method is based on the assumption that levels of recoil implanted 210Po in the glass provide a measure of time integrated radon concentration in the environment in which the glass has been located. The surface deposited activity of the radon progenies, which then become implanted in the glass by alpha recoil, is believed to reflect past exposure to airborne activity. Such retrospective measurements on glass are valuable in estimating the human dose derived from radon during the time of exposure. In this paper an account is given of the principles and some field applications of a retrospective technique, using the alpha track detectors, CR-39 and LR-115, to measure 210Po implanted in glass surfaces (surface traps). By using this CR-LR difference technique, the cumulative radon exposure in a dwelling in past decades may be estimated. This method provides reliable radon exposure data as a support to epidemiological studies concerning the health effects of radon exposure in the living environment.

  11. Rapid determination of (210)Pb and (210)Po in water and application to marine samples.

    PubMed

    Villa-Alfageme, M; Mas, J L; Hurtado-Bermudez, S; Masqué, P

    2016-11-01

    Measurement of radionuclides in marine samples, specifically radioactive pairs disequilibrium, has gained interest lately due to their ability to trace cutting edge biogeochemical processes. In this context, we developed a fast, direct method for determining (210)Pb and (210)Po water through the use of ultra low-level liquid scintillation counting and alpha-particle spectrometry respectively and through Eichrom Sr resins for the Po-Pb separation. For (210)Pb analysis, the method uses stable lead as a yield tracer measured by a robust ICP-MS technique, and (210)Po is determined through self-deposition using the conventional (209)Po yield tracer. The improvements of the method over other techniques are: a) the analysis can be completed within 6 days, simplifying other methods, b) very low limits of detection have been achieved -0.12 and 0.005mBqL(-1) for (210)Pb and (210)Po, respectively - and c) most of the method could be carried out in on-board analysis. We applied the method to different aqueous samples and specifically to marine samples. We determined (210)Pb and (210)Po in the dissolved fraction of Mediterranean Sea water and an estuary at the South-West of Spain. We found that it can be successfully employed to marine samples but we recommend to i) use a minimum of 20L water to measure the (210)Pb in the dissolved phase by LSC and lower volumes to measure total concentrations; ii) wait for (210)Pb and (210)Bi in secular equilibrium and measure the total spectrum to minimise the limit of detection and improve accuracy.

  12. Occurrence and distribution of 210Pb and 210Po in selected California groundwater wells.

    PubMed

    Ruberu, Shiyamalie R; Liu, Yun-Gang; Perera, S Kusum

    2007-05-01

    Groundwater wells from across the State of California were sampled and analyzed for Pb and Po. The separation method involved Fe(OH)3 precipitation from a 5-L groundwater sample followed by electrodeposition of Po on a nickel disk. The resulting solution was passed through an ion-exchange resin column for the isolation of Pb. De-ionized water spiked at a concentration range from 4.92 mBq L(-1) to 755 mBq L(-1) with these radionuclide standards showed excellent accuracy and precision of the method. In the groundwater wells, overall activity of Pb ranged from 3.7 mBq L(-1) to 1,481 mBq L(-1) and the Po activity ranged from 0.25 mBq L(-1) to 555 mBq L(-1). Of the select wells tested, 27% for Pb and 19% for Po were above the proposed maximum contamination limits for these radionuclides, which are set at 37 mBq L(-1) and 26 mBq L(-1), respectively. From a public health perspective this is a concern, since the drinking water screening levels for gross alpha is at 555 mBq L(-1) and gross beta is at 1,850 mBq L(-1). At such high screening levels Pb and Po will not be captured, and this situation was found in several of the wells studied. The occurrence of Pb and Po are not correlated within the sources, however; the polonium concentrations were always lower than the lead concentrations. Activities of Pb measured from wells two years apart clearly demonstrated the continuous flux of groundwater within aquifers.

  13. Rapid determination of (210)Pb and (210)Po in water and application to marine samples.

    PubMed

    Villa-Alfageme, M; Mas, J L; Hurtado-Bermudez, S; Masqué, P

    2016-11-01

    Measurement of radionuclides in marine samples, specifically radioactive pairs disequilibrium, has gained interest lately due to their ability to trace cutting edge biogeochemical processes. In this context, we developed a fast, direct method for determining (210)Pb and (210)Po water through the use of ultra low-level liquid scintillation counting and alpha-particle spectrometry respectively and through Eichrom Sr resins for the Po-Pb separation. For (210)Pb analysis, the method uses stable lead as a yield tracer measured by a robust ICP-MS technique, and (210)Po is determined through self-deposition using the conventional (209)Po yield tracer. The improvements of the method over other techniques are: a) the analysis can be completed within 6 days, simplifying other methods, b) very low limits of detection have been achieved -0.12 and 0.005mBqL(-1) for (210)Pb and (210)Po, respectively - and c) most of the method could be carried out in on-board analysis. We applied the method to different aqueous samples and specifically to marine samples. We determined (210)Pb and (210)Po in the dissolved fraction of Mediterranean Sea water and an estuary at the South-West of Spain. We found that it can be successfully employed to marine samples but we recommend to i) use a minimum of 20L water to measure the (210)Pb in the dissolved phase by LSC and lower volumes to measure total concentrations; ii) wait for (210)Pb and (210)Bi in secular equilibrium and measure the total spectrum to minimise the limit of detection and improve accuracy. PMID:27591584

  14. Enhanced apatite formation on Ti metal heated in PO2-controlled nitrogen atmosphere.

    PubMed

    Hashimoto, Masami; Hayashi, Kazumi; Kitaoka, Satoshi

    2013-10-01

    The oxynitridation of biomedical titanium metal under a precisely regulated oxygen partial pressure (PO2) of 10(-14)Pa in nitrogen atmosphere at 973 K for 1 h strongly enhanced apatite formation compared with that on Ti heated in air. The factors governing the high apatite-forming ability are discussed from the viewpoint of the surface properties of Ti heated under a PO2 of 10(-14)Pa in nitrogen atmosphere determined from X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and zeta potential measurements. Nitrogen (N)-doped TiO2 (interstitial N) was formed on pure Ti heated under a PO2 of 10(-14)Pa in nitrogen atmosphere at 973 K. The XPS O1s main peak shifted toward a lower binding energy upon heating under a PO2 of 10(-14)Pa. This shift may be due to the formation of oxygen vacancies. This Ti surface had a positive zeta potential of approximately 20 mV. According to time-of-flight secondary ion mass spectroscopy results, PO4(3-) ions were predominantly adsorbed on Ti soaked in simulated body fluid (SBF) after heat treatment, followed by calcium ions. It was concluded that the apatite formation kinetics can be described using the Avrami-Erofeev equation with an Avrami index of n=2, which implies the instantaneous nucleation of apatite on the surface of Ti soaked in SBF after heat treatment at 973 K under a PO2 of 10(-14)Pa.

  15. Measurement of the {sup 214}Po half-life by the DEVIS track setup

    SciTech Connect

    Belov, V. A.; Brakhman, E. V.; Zeldovich, O. Ya.; Karelin, A. K.; Kirichenko, V. V.; Kobyakin, A. S. Kozodaeva, O. M.; Kuchenkov, A. V.; Tsvetkova, T. N.

    2013-04-15

    Measurement of the {sup 214}Po half-life with the DEVIS track setup at the Institute of Theoretical and Experimental Physics (ITEP, Moscow) by means of a procedure based on determining lifetimes of individual nuclei is described. The value obtained for the {sup 214}Po half-life is 163.8 {+-} 3.0 Micro-Sign s. The possibility of reaching the accuracy of the measurements that is required for testing the statement that the decay of some nuclei has a nonexponential character and the source intensity necessary for this are discussed.

  16. The influence of intruder states in even-even Po isotopes

    SciTech Connect

    García-Ramos, J. E.; Heyde, K.

    2015-10-15

    We study the role of intruder states and shape coexistence in the even-even {sup 190–206}Po isotopes, through an interacting boson model with configuration mixing calculation. We analyzed the results in the light of known systematics on various observable in the Pb region, paying special attention to the unperturbed energy systematics and quadrupole deformation. We find that shape coexistence in the Po isotopes behaves in very much the same way as in the Pt isotopes, i.e., it is somehow hidden, contrary to the situation in the Pb and the Hg isotopes.

  17. The inflow of polonium (210)Po from Vistula river catchments area.

    PubMed

    Skwarzec, Bogdan; Jahnz, Anna

    2007-12-01

    The activities of polonium (210)Po in Vistula unfiltered water samples, collected from November 2002 to November 2003, were measured using the alpha spectrometry. In winter, the highest concentration of (210)Po was in Vistula river water from Torun (2.72 +/- 0.04 Bq x m(-3)) and from the Wieprz river (5.46 +/- 0.07 Bq x m(-3) [Bequerel per cubic metre]), and the lowest was in water from Nida river (0.59 +/- 0.02 Bq x m(-3)). During spring, the highest concentration of (210)Po was observed in Vistula water collected in Deblin (5.98 +/- 0.03 Bq x m(-3)) and the lowest in water from the Narew river (1.20 +/- 0.12 Bq x m(-3)). In summer, the highest concentration of (210)Po was in Nogat river water collected in Malbork (3.18 +/- 0.04 Bq x m(-3)) and the Bzura river (5.30 +/- 0.02 Bq x m(-3)), the lowest in Wieprz river (0.49 +/- 0.09 Bq x m(-3)) and Vistula river water from Kraków (1.44 +/- 0.05 Bq x m(-3)). In autumn, the highest (210)Po concentration was in Bzura river (8.93 +/- 0.03 Bq x m(-3)), the lowest in Vistula water from Grudziadz (1.51 +/- 0.04 Bq x m(-3)), and Toruń (1.89 +/- 0.05 Bq x m(-3)). The highest quantity of (210)Po was transported from Vistula catchments area to the Baltic Sea in spring and the lowest in summer. Annually, the southern Baltic Sea is enriched by about 73.7 GBq (210)Po (with Leniwka and Nogat rivers), with 71.6 GBq going to Gdańsk Bay and 2.1 GBq to Vistula Lagoon. The highest surface (210)Po runoff was observed in spring (to 1370 kBq x km(-2) x quarter(-1) for Dunajec catchment's area), the lowest in summer (for Nida catchment's area to 100 kBq x km(-2) x quarter(-1)).

  18. Fission barriers for Po nuclei produced in complete fusion reactions with heavy ions

    SciTech Connect

    Sagaidak, R. N.; Andreyev, A. N.

    2009-05-15

    Evaporation residues and fission excitation functions obtained in complete fusion reactions leading to Po compound nuclei have been analyzed in the framework of the standard statistical model. Macroscopic fission barriers deduced from the cross-section data analysis are compared with the predictions of various theoretical models and available data. A drop in the Po barriers with the decrease in a neutron number was found, which is stronger than predicted by any theory. The presence of entrance channel effects and collective excitations in the compound nucleus decay is considered as a possible reason for the barrier reduction.

  19. {alpha} transitions to coexisting 0{sup +} states in Pb and Po isotopes

    SciTech Connect

    Xu Chang; Ren Zhongzhou

    2007-04-15

    The {alpha}-transitions ({delta}l=0) to ground and first excited 0{sup +} states in neutron deficient Pb and Po isotopes are systematically analyzed by the density-dependent cluster model. The magnitude of nuclear deformation of the coexisting 0{sub 1}{sup +} and 0{sub 2}{sup +} states is extracted directly from the experimental {alpha}-decay energies and half-lives. The phenomenon of shape coexistence around the Z=82 shell closure is clearly demonstrated in our present analysis. The obtained deformation values from Rn {yields} Po {yields} Pb decay chains are generally consistent with both the available experimental and theoretical studies.

  20. Distribution of Po-210 in two species of predatory marine fish from the Brazilian coast.

    PubMed

    Mársico, E T; Ferreira, M S; São Clemente, S C; Gouvea, R C S; Jesus, E F O; Conti, C C; Conte, C A; Kelecom, A G A C

    2014-02-01

    Polonium-210 ((210)Po) concentration was quantified in the muscle tissue and organs of two predatory marine fishes (Genypterus brasiliensis and Cynoscion microlepidotus) from Cabo Frio, Rio de Janeiro, Brazil. The species C. microlepidotus, a benthic carnivore, registered higher (210)Po in its tissue. The organs associated with digestion displayed the maximum radionuclide compared with other organs. The average activity was 2 mBq kg(-1) for G. brasiliensis and it was 6 mBq kg(-1) for C. microlepidotus. The activity concentrations varied significantly between the species and among organs.

  1. Comparison of various dissolution techniques for determination of Po-210 in biological samples.

    PubMed

    Planinšek, P; Benedik, L; Smodiš, B

    2013-11-01

    The aim of the present study was to compare three wet digestion procedures for dissolution of biological samples in the determination of Po-210. Classical wet ashing over a gas flame with acids in a long-necked Kjeldahl flask, digestion with acids in an Erlenmeyer flask and microwave digestion in a Teflon vessel at temperatures at up to 200°C were investigated. The results obtained showed that the activity concentrations of Po-210 found in the samples analysed were comparable for all the procedures used.

  2. Carbon Surface Layers on a High-Rate LiFePO4

    SciTech Connect

    Gabrisch, Heike; Wilcox, James D.; Doeff, Marca M.

    2005-09-06

    Transmission electron microscopy (TEM) was used to image particles of a high-rate LiFePO4 sample containing a small amount of in situ carbon. The particle morphology is highly irregular, with a wide size distribution. Nevertheless, coatings, varying from about 5-10 nm in thickness, could readily be detected on surfaces of particles as well as on edges of agglomerates. Elemental mapping using Energy Filtered TEM (EFTEM) indicates that these very thin surface layers are composed of carbon. These observations have important implications for the design of high-rate LiFePO4 materials in which, ideally, a minimal amount of carbon coating is used.

  3. Electrical conductivity studies of graphene wrapped nanocrystalline LiMnPO4 composite

    NASA Astrophysics Data System (ADS)

    Cheruku, Rajesh; D, Surya Bhaskaram; Govindaraj, G.; Vijayan, Lakshmi

    2015-06-01

    Nanocrystalline LiMnPO4 material was synthesized by template free sucrose assisted hydrothermal method. The material possesses the orthorhombic crystal structure with Pnma, space group having four formula units. The GO was prepared by the hummer's method and it was reduced graphene oxide (rGO) with hydrazine hydrate in the presence of nitrogen atmosphere. LiMnPO4 material was wrapped by the rGO to increase its conductivity. The structural characterization was accomplished through X-ray diffraction, FT-IR and Raman spectroscopy. Morphology was identified by the SEM, Electrical characterization was done through impedance spectroscopy and the results were reported.

  4. Tunable luminescence and energy transfer of TbPO4:Eu3+ nanocrystals

    NASA Astrophysics Data System (ADS)

    Lü, Jiantao; Fan, Ting; Xie, Jianing; Chen, Guojie

    2013-01-01

    We report the synthesis of Tb(1-x)PO4:xEu3+ (x=0-1) nanophosphors directly by a simple hydrothermal method with citric acid (CA) as the organic additive and without further sintering treatment. The nanocrystals are well-faceted and show a highly symmetrical structure. The energy transfer between Tb3+ and Eu3+ in TbPO4 nanocrystal was investigated, and tunable emission wavelengths were realized in the materials by changing the doping concentration of Eu3+. The increase of Eu3+ concentration can lead to the interaction between neighboring Eu3+, which results in concentration quenching.

  5. Distribution of Po-210 in two species of predatory marine fish from the Brazilian coast.

    PubMed

    Mársico, E T; Ferreira, M S; São Clemente, S C; Gouvea, R C S; Jesus, E F O; Conti, C C; Conte, C A; Kelecom, A G A C

    2014-02-01

    Polonium-210 ((210)Po) concentration was quantified in the muscle tissue and organs of two predatory marine fishes (Genypterus brasiliensis and Cynoscion microlepidotus) from Cabo Frio, Rio de Janeiro, Brazil. The species C. microlepidotus, a benthic carnivore, registered higher (210)Po in its tissue. The organs associated with digestion displayed the maximum radionuclide compared with other organs. The average activity was 2 mBq kg(-1) for G. brasiliensis and it was 6 mBq kg(-1) for C. microlepidotus. The activity concentrations varied significantly between the species and among organs. PMID:24334195

  6. TL-OSL study of Li{sub 3}PO{sub 4}: Mg, Cu phosphor

    SciTech Connect

    Rahangdale, S. R. Wankhede, S. P.; Dhabekar, B. S.; Palikundwar, U. A.; Moharil, S. V.

    2015-08-28

    In the present work, we report the thermoluminescence and optically stimulated luminescence properties of Mg and Cu doped Li{sub 3}PO{sub 4} phosphor. The phosphor was synthesized by precipitation method. The thermoluminescence dosimetric peak temperature for the phosphor varies with concentrations of Mg and Cu. Li{sub 3}PO{sub 4} shows good response to 470nm optical stimulation. The OSL sensitivity of the phosphor is approximately 12 times than that of standard Lithium magnesium phosphate. This study may help to develop this material for the application in real time dosimetry using optically stimulated luminescence.

  7. JPL Physical Oceanography Distributed Active Archive Center (PO.DAAC) data availability, version 1-94

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The Physical Oceanography Distributed Active Archive Center (PO.DAAC) archive at the Jet Propulsion Laboratory (JPL) includes satellite data sets for the ocean sciences and global-change research to facilitate multidisciplinary use of satellite ocean data. Parameters include sea-surface height, surface-wind vector, sea-surface temperature, atmospheric liquid water, and integrated water vapor. The JPL PO.DAAC is an element of the Earth Observing System Data and Information System (EOSDIS) and is the United States distribution site for Ocean Topography Experiment (TOPEX)/POSEIDON data and metadata.

  8. Electrical conductivity studies of graphene wrapped nanocrystalline LiMnPO{sub 4} composite

    SciTech Connect

    Cheruku, Rajesh; D, Surya Bhaskaram; Govindaraj, G.; Vijayan, Lakshmi

    2015-06-24

    Nanocrystalline LiMnPO{sub 4} material was synthesized by template free sucrose assisted hydrothermal method. The material possesses the orthorhombic crystal structure with Pnma, space group having four formula units. The GO was prepared by the hummer’s method and it was reduced graphene oxide (rGO) with hydrazine hydrate in the presence of nitrogen atmosphere. LiMnPO{sub 4} material was wrapped by the rGO to increase its conductivity. The structural characterization was accomplished through X-ray diffraction, FT-IR and Raman spectroscopy. Morphology was identified by the SEM, Electrical characterization was done through impedance spectroscopy and the results were reported.

  9. TEM Studies of Carbon Coated LiFePO4 after Charge DischargeCycling

    SciTech Connect

    Gabrisch, H.; Wilcox, J.; Doeff, M.

    2006-11-30

    Carbon coating has proven to be a successful approach toimprove the rate capability of LiFePO4 used in rechargeable Li-ionbatteries. Investigations of the microstructure of carbon coated LiFePO4after charge discharge cycling shows that the carbon surface layerremains intact over 100 cycles. We find micro cracks in the cycledmaterial that extend parallel to low indexed lattice planes. Ourobservations differ from observations made by other authors. However thedifferences between the orientations of crack surfaces in both studiescan be reconciled considering the location of weak bonds in the unit celland specimen geometry as well as elastic stress fields ofdislocation.

  10. We Need You! The Importance of Scientist Involvement in Education and Public Outreach (E/PO)

    NASA Astrophysics Data System (ADS)

    Buxner, S.; Hsu, B. C.; Meinke, B. K.; Shipp, S. S.; Schwerin, T. G.; Peticolas, L. M.; Smith, D.; Dalton, H.

    2013-12-01

    Active engagement of scientists in education and public outreach (E/PO) activities is beneficial for scientists, classrooms, and the general public. Scientist visibility in the public arena is important to garner public support, whose tax dollars fund scientific programs. Scientists are important disseminators of current, accurate scientific knowledge. They also, perhaps more importantly, understand the nature and process of science and have the means of understanding and addressing many of the issues facing society. Research has shown that while the public is interested in science, not all members are necessarily scientifically literate; additionally there is evidence than many students are not prepared for, or choosing to participate in science careers. And yet, a scientifically engaged, literate, and supportive public is a necessary partner in addressing important global challenges of the future. E/PO is a wonderful opportunity for scientists to demonstrate that science is interesting, exciting, fun, challenging, and relevant to society. In doing so, they can transfer ownership of science to the public through a variety of vehicles by increasing access to scientific thought and discovery. Through partnerships with E/PO professionals, teachers, or journalists, scientists can improve their communication and teaching skills, whether in an E/PO setting or their higher education careers. Sharing with the public what scientists do is an effective way to engage people in the scientific process and to express scientists' enthusiasm for what they do. Scientist involvement in E/PO also shows the public that scientists are real people and provides important role models for the next generation of scientists. There are many opportunities to get involved in E/PO! Find information on EarthSpace, a national clearinghouse for higher education materials in Earth and space science through an abstract by Nicholas Gross, et al. Learn about NASA Science Mission Directorate (SMD

  11. Rising from the Dead: the Revival of the EUVE E/PO

    NASA Astrophysics Data System (ADS)

    Cullison, J. L.; Craig, N.; Stroozas, B. A.; Malina, R. F.

    2000-05-01

    NASA's Extreme Ultraviolet Explorer (EUVE) is dedicated to gathering data on our sky via instrumentation sensitive to the region of light between 76 and 760 angstroms. Since the all-sky survey was completed in 1993, astronomers have made studies of selected objects with EUVE to determine their physical properties and chemical compositions. Also, they have learned about the conditions that prevail and the processes at work in stars, planets, and other sources of EUV radiation. In its pre-launch and early prime mission, EUVE had a thriving education and public outreach (E/PO) program formed expressly to spread the word on recent EUVE findings, but due to budgetary restraints in its extended mission, the project has been unable in recent years to support extensive E/PO efforts. Now in it's eighth year of operation, the EUVE Project has revived its E/PO efforts without significantly impacting its shoe-string budget. Web sites are being reconstructed, including sophisticated interactive learning environments where elementary through college level students, teachers, and the general public can select from lesson plans including, for example, an introductory astronomical module on the relationship between spectra and object classification, download three-dimensional cutouts of the EUVE skymap, view a slide show on the history and instrumentation of the satellite, take a virtual tour of the EUVE observatory, find where EUVE is in its orbit, and catch up on EUVE's most recent news and events. EUVE's revived internet E/PO presence is supplemented with staff and technical support (up to 10% of each staff person's time) of hands-on elementary and community projects coordinated by the UC Berkeley Center for Science Education (the now independent offshoot of the original EUVE E/PO). All elements of the EUVE E/PO are supported without impacting the efficient and highly productive science goals of the small-staffed mission. Additional EUVE E/PO efforts in the works include

  12. AgI/Ag{sub 3}PO{sub 4} hybrids with highly efficient visible-light driven photocatalytic activity

    SciTech Connect

    Katsumata, Hideyuki; Hayashi, Takahiro; Taniguchi, Masanao; Suzuki, Tohru; Kaneco, Satoshi

    2015-03-15

    Highlights: • AgI/Ag{sub 3}PO{sub 4} hybrid was prepared via an in situ anion-exchange method. • AgI/Ag{sub 3}PO{sub 4} displays the excellent photocatalytic activity under visible light. • AgI/Ag{sub 3}PO{sub 4} readily transforms to be Ag@AgI/Ag{sub 3}PO{sub 4} system. • h{sup +} and O{sub 2}{sup ·−} play the major role in the AO 7 decolorization over AgI/Ag{sub 3}PO{sub 4}. • The activity enhancement is ascribed to a Z-scheme system composed of Ag{sub 3}PO{sub 4}, Ag and AgI. - Abstract: Highly efficient visible-light-driven AgI/Ag{sub 3}PO{sub 4} hybrid photocatalysts with different mole ratios of AgI were prepared via an in situ anion-exchange method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) technique. Under visible light irradiation (>420 nm), the AgI/Ag{sub 3}PO{sub 4} photocatalysts displayed the higher photocatalytic activity than pure Ag{sub 3}PO{sub 4} and AgI for the decolorization of acid orange 7 (AO 7). Among the hybrid photocatalysts, AgI/Ag{sub 3}PO{sub 4} with 80% of AgI exhibited the highest photocatalytic activity for the decolorization of AO 7. X-ray photoelectron spectroscopy (XPS) results revealed that AgI/Ag{sub 3}PO{sub 4} readily transformed to be Ag@AgI/Ag{sub 3}PO{sub 4} system while the photocatalytic activity of AgI/Ag{sub 3}PO{sub 4} remained after 5 recycling runs. In addition, the quenching effects of different scavengers displayed that the reactive h{sup +} and O{sub 2}{sup ·−} play the major role in the AO 7 decolorization. The photocatalytic activity enhancement of AgI/Ag{sub 3}PO{sub 4} hybrids can be ascribed to the efficient separation of electron–hole pairs through a Z-scheme system composed of Ag{sub 3}PO{sub 4}, Ag and AgI, in which Ag nanoparticles act as the charge separation center.

  13. Continuous flame aerosol synthesis of carbon-coated nano-LiFePO(4) for Li-ion batteries.

    PubMed

    Waser, Oliver; Büchel, Robert; Hintennach, Andreas; Novák, Petr; Pratsinis, Sotiris E

    2011-10-01

    Core-shell, nano-sized LiFePO(4)-carbon particles were made in one step by scalable flame aerosol technology at 7 g/h. Core LiFePO(4) particles were made in an enclosed flame spray pyrolysis (FSP) unit and were coated in-situ downstream by auto thermal carbonization (pyrolysis) of swirl-fed C(2)H(2) in an O(2)-controlled atmosphere. The formation of acetylene carbon black (ACB) shell was investigated as a function of the process fuel-oxidant equivalence ratio (EQR). The core-shell morphology was obtained at slightly fuel-rich conditions (1.0PO(4) particles were formed at fuel-lean conditions (0.8PO(4) with a crystal size of 65 nm and 30 wt% ACB content. Uncoated LiFePO(4) or segregated LiFePO(4)-ACB grew to 250 nm at these conditions. Annealing at 800 °C induced carbothermal reduction of LiFePO(4) to Fe(2)P by ACB shell consumption that resulted in cavities between carbon shell and core LiFePO(4) and even slight LiFePO(4) crystal growth but better electrochemical performance. The present carbon-coated LiFePO(4) showed superior cycle stability and higher rate capability than the benchmark, commercially available LiFePO(4). PMID:23407817

  14. Continuous flame aerosol synthesis of carbon-coated nano-LiFePO4 for Li-ion batteries

    PubMed Central

    Waser, Oliver; Büchel, Robert; Hintennach, Andreas; Novák, Petr; Pratsinis, Sotiris E.

    2013-01-01

    Core-shell, nanosized LiFePO4-carbon particles were made in one step by scalable flame aerosol technology at 7 g/h. Core LiFePO4 particles were made in an enclosed flame spray pyrolysis (FSP) unit and were coated in-situ downstream by auto thermal carbonization (pyrolysis) of swirl-fed C2H2 in an O2-controlled atmosphere. The formation of acetylene carbon black (ACB) shell was investigated as a function of the process fuel-oxidant equivalence ratio (EQR). The core-shell morphology was obtained at slightly fuel-rich conditions (1.0 < EQR < 1.07) whereas segregated ACB and LiFePO4 particles were formed at fuel-lean conditions (0.8 < EQR < 1). Post-annealing of core-shell particles in reducing environment (5 vol% H2 in argon) at 700 °C for up to 4 hours established phase pure, monocrystalline LiFePO4 with a crystal size of 65 nm and 30 wt% ACB content. Uncoated LiFePO4 or segregated LiFePO4-ACB grew to 250 nm at these conditions. Annealing at 800 °C induced carbothermal reduction of LiFePO4 to Fe2P by ACB shell consumption that resulted in cavities between carbon shell and core LiFePO4 and even slight LiFePO4 crystal growth but better electrochemical performance. The present carbon-coated LiFePO4 showed superior cycle stability and higher rate capability than the benchmark, commercially available LiFePO4. PMID:23407817

  15. (210)Po in drinking water, its potential health effects, and inadequacy of the gross alpha activity MCL.

    PubMed

    Seiler, Ralph

    2016-10-15

    Polonium-210 ((210)Po) is a naturally-occurring, carcinogenic member of the (238)U decay series and the granddaughter of (210)Pb. It has a half life of 138.4days and is rarely found in drinking water at levels exceeding 5mBq/L because it strongly binds to aquifer sediment. When the current US Maximum Contaminant Level (MCL) covering (210)Po was promulgated in December 2000, very little was known about its occurrence and the processes responsible for mobilizing it. More is now known about the processes that mobilize (210)Po from sediments and a review of recent occurrence data show that it may not be as rare in the US as the US Environmental Protection Agency (USEPA) thought in 2000. Worldwide, only about 2200 analyses for (210)Po in drinking water were identified, with activities exceeding 500mBq/L being found only in Finland, India, Sweden, and the US. The median of 400 (210)Po analyses from the US is 4.75mBq/L and >10% of the samples exceed 500mBq/L. Current compliance-monitoring regulations in the US essentially guarantee that (210)Po contamination will not be detected except in very contaminated wells. Major problems with the US Gross Alpha Activity MCL include the volatility of (210)Po and extended holding times and sample-compositing methods that can allow the majority of (210)Po in a sample bottle to decay before analysis. In light of new information, the radionuclide rule should be changed and direct measurements of (210)Po should be made in all public-water supply wells to rule out its presence. Much of the important biological and toxicological research on (210)Po is more than four decades old and new laboratory research using modern tools is needed. Biological and epidemiological investigations of known contaminated areas are needed to assess the effect (210)Po exposure is having on animals and humans consuming the water.

  16. Synthesis, structure, and optical properties of CsU{sub 2}(PO{sub 4}){sub 3}

    SciTech Connect

    Oh, George N.; Ringe, Emilie; Van Duyne, Richard P.; Ibers, James A.

    2012-01-15

    CsU{sub 2}(PO{sub 4}){sub 3} was synthesized in highest yield by the reaction in a fused-silica tube of U, P, and Se in a CsCl flux at 1273 K. It crystallizes with four formula units in space group P2{sub 1}/n of the monoclinic system in a new structure type. The structure of CsU{sub 2}(PO{sub 4}){sub 3} is composed of U and Cs atoms coordinated by PO{sub 4}{sup 3-} units in distorted octahedral arrangements. Each U atom corner shares with six PO{sub 4}{sup 3-} units. Each Cs atom face shares with one, edge shares with two, and corner shares with three PO{sub 4}{sup 3-} units. The structure shares some features with the sodium zirconium phosphate structure type. X-ray powder diffraction results demonstrate that the present CsU{sub 2}(PO{sub 4}){sub 3} compound crystallizes in a structure different from the previously reported {beta} Prime - and {gamma}-CsU{sub 2}(PO{sub 4}){sub 3} compounds. CsU{sub 2}(PO{sub 4}){sub 3} is highly pleochroic, as demonstrated by single-crystal optical absorption measurements. - Graphical abstract: Stacking of the layers in CsU{sub 2}(PO{sub 4}){sub 3}, viewed along [100]. Highlights: Black-Right-Pointing-Pointer Compound CsU{sub 2}(PO{sub 4}){sub 3} crystallizes in a new structure type. Black-Right-Pointing-Pointer Structure shares some features with the sodium zirconium phosphate structure type. Black-Right-Pointing-Pointer CsU{sub 2}(PO{sub 4}){sub 3} is highly pleochroic, as demonstrated by single-crystal optical absorption measurements.

  17. Negative regulation of prophenoloxidase (proPO) activation by a clip-domain serine proteinase homolog (SPH) from endoparasitoid venom.

    PubMed

    Zhang, Guangmei; Lu, Zhi-Qiang; Jiang, Haobo; Asgari, Sassan

    2004-05-01

    Most parasitic wasps inject maternal factors into the host hemocoel to suppress the host immune system and ensure successful development of their progeny. Melanization is one of the insect defence mechanisms against intruding pathogens or parasites. We previously isolated from the venom of Cotesia rubecula a 50 kDa protein that blocked melanization in the hemolymph of its host, Pieris rapae [Insect Biochem. Mol. Biol. 33 (2003) 1017]. This protein, designated Vn50, is a serine proteinase homolog (SPH) containing an amino-terminal clip domain. In this work, we demonstrated that recombinant Vn50 bound P. rapae hemolymph components that were recognized by antisera to Tenebrio molitor prophenoloxidase (proPO) and Manduca sexta proPO-activating proteinase (PAP). Vn50 is stable in the host hemolymph-it remained intact for at least 72 h after parasitization. Using M. sexta as a model system, we found that Vn50 efficiently down-regulated proPO activation mediated by M. sexta PAP-1, SPH-1, and SPH-2. Vn50 did not inhibit active phenoloxidase (PO) or PAP-1, but it significantly reduced the proteolysis of proPO. If recombinant Vn50 binds P. rapae proPO and PAP (as suggested by the antibody reactions), it is likely that the molecular interactions among M. sexta proPO, PAP-1, and SPHs were impaired by this venom protein. A similar strategy might be employed by C. rubecula to negatively impact the proPO activation reaction in its natural host.

  18. Transfer of {sup 210}Po and {sup 210}Pb through the lichen-caribou-wolf food chain of northern Canada

    SciTech Connect

    Thomas, P.A.; Sheard, J.W.; Swanson, S.

    1994-06-01

    Natural background activity and food chain transfer of the uranium decay products, {sup 210}Po and {sup 210}Pb, were examined in the lichen-caribou-wolf food chain at two locations in the Northwest Territories of Canada. {sup 210}Po and {sup 210}Pb activities in lichens differed with species and location. Both {sup 210}Po and {sup 210}Pb were markedly higher in caribou bone than in wolf bone. {sup 210}Po activities in liver, kidney, and muscle were similar in both species. Caribou fetuses had lower activities of {sup 210}Po but higher activities of {sup 210}Pb than maternal muscle and placenta, suggesting greater placental transport of {sup 210}Pb than {sup 210}Po. Concentration ratios (CR = Bq kg{sup {minus}1} in consumer/Bq kg{sup {minus}1} in its food source) and f{sub f} values (f{sub f} in d kg{sup {minus}1} = Bq kg{sup {minus}1} in muscle/Bq d{sup {minus}1} ingested) showed that wolves retain more {sup 210}Po and less {sup 210}Pb from their diet than do caribou. {sup 210}Po CRs averaged 0.38 for caribou/lichens, 0.26 for caribou/rumen contents, and 0.40 for wolves/caribou. {sup 210}Pb CRs averaged 0.36 for caribou/lichens, 0.57 for caribou/rumen contents, and 0.13 for wolves/caribou. 43 refs., 4 figs., 5 tabs.

  19. Synthesis and tunable luminescence of RbCaGd(PO4)2:Ce3+, Mn2+ phosphors

    NASA Astrophysics Data System (ADS)

    Chen, Xue; Lv, Fengzhu; Li, Penggang; Zhang, Yihe

    2016-04-01

    RbCaGd(PO4)2 doped with Ce3+, Mn2+ was synthesized by the sol-gel method. The crystal structure and crystallographic location of Ce3+ in RbCaGd(PO4)2 were identified by Rietveld refinement. Powder X-ray diffraction (XRD) revealed that the structure of RbCaGd(PO4)2:Ce3+ compounds is hexagonal structure which is similar to that of hexagonal LnPO4 with the lattice constant of a = b = 7.005(57) Å, c = 6.352(05) Å, and V (cell volume) = 269.980 Å3. The photoluminescence behavior and emission mechanism were studied systematically by doping activators in the RbCaGd(PO4)2 host. The Mn2+ incorporated RbCaGd(PO4)2:Ce3+, Mn2+ compounds exhibited blue emission from the parity- and spin-allowed f-d transition of Ce3+ and orange-to-red emission from the forbidden 4T1 → 6A1 transition of Mn2+. The emission chromaticity coordinates of RbCaGd(PO4)2:0.10Ce3+, xMn2+ (x = 0.16, 0.25) are close to the white region due to an energy transfer process and the energy transfer mechanism from Ce3+ to Mn2+ in the RbCaGd(PO4)2 host was dominated by dipole-dipole interactions.

  20. Conductive surface modification of LiFePO4 with nitrogen doped carbon layers for lithium-ion batteries

    SciTech Connect

    Yoon, Sukeun; Liao, Chen; Sun, Xiao-Guang; Bridges, Craig A; Unocic, Raymond R; Nanda, Jagjit; Dai, Sheng; Paranthaman, Mariappan Parans

    2012-01-01

    The LiFePO4 rod surface modified with nitrogen doped carbon layer has been prepared using hydrothermal processing followed by post-annealing in the presence of an ionic liquid. The coated LiFePO4 rod exhibits good capacity retention and high rate capability as the nitrogen doped carbon improves conductivity and prevents aggregation of the rod during cycling.

  1. The Polysemy of an "Empty" Prefix: A Corpus-Based Cognitive Semantic Analysis of the Russian Verbal Prefix po-

    ERIC Educational Resources Information Center

    LeBlanc, Nicholas Lance

    2010-01-01

    This dissertation proposes a structured semantic account of the polysemous Russian verbal prefix "po-" within the theoretical framework of cognitive linguistics and using corpus linguistic methods. While scholarly consensus identifies five meanings for "po-" and an additional meaning in conjunction with the suffix--"yva"--, the relationships among…

  2. Transfer of 210Po and 210Pb through the lichen-caribou-wolf food chain of northern Canada.

    PubMed

    Thomas, P A; Sheard, J W; Swanson, S

    1994-06-01

    Natural background activity and food chain transfer of the uranium decay products, 210Po and 210Pb, were examined in the lichen-caribou-wolf food chain at two locations in the Northwest Territories of Canada. 210Po and 210Pb activities in lichens differed with species and location. Both 210Po and 210Pb were markedly higher in caribou bone than in wolf bone. 210Po activities in liver, kidney, and muscle were similar in both species. Caribou fetuses had lower activities of 210Po but higher activities of 210Pb than maternal muscle and placenta, suggesting greater placental transport of 210Pb than 210Po. Concentration ratios (CR = Bq kg-1 in consumer/Bq kg-1 in its food source) and ff values (ff in d kg-1 = Bq kg-1 in muscle/Bq d-1 ingested) showed that wolves retain more 210Po and less 210Pb from their diet than do caribou. 210Po CRs averaged 0.38 for caribou/lichens, 0.26 for caribou/rumen contents, and 0.40 for wolves/caribou. 210Pb CRs averaged 0.36 for caribou/lichens, 0.57 for caribou/rumen contents, and 0.13 for wolves/caribou.

  3. DEMONSTRATION BULLETIN: PO*WW*ER™ WASTEWATER TREATMENT SYSTEMS - LAKES CHARLES TREATMENT CENTER - CHEMICAL WASTE MANAGEMENT, INC.

    EPA Science Inventory

    The PO*WW*ER™ system developed by Chemical Waste Management, Inc. (CWM), reduces the volume of aqueous waste and catalytically oxidizes volatile contaminants. The PO*WW*ER™ system consists primarily of (1) an evaporator that reduces influent wastewater volume, (2) a catalytic o...

  4. Double Carbon Nano Coating of LiFePO4 Cathode Material for High Performance of Lithium Ion Batteries.

    PubMed

    Ding, Yan-Hong; Huang, Guo-Long; Li, Huan-Huan; Xie, Hai-Ming; Sun, Hai-Zhu; Zhang, Jing-Ping

    2015-12-01

    Double carbon-coated LiFePO4 (D-LiFePO4/C) composite with sphere-like structure was synthesized through combination of co-precipitation and solid-state methods. Cetyl-trimethyl-ammonium bromide (CTAB) and citric acid served as two kinds of carbon sources in sequence. SEM images demonstrated that double carbon coating had certain influence on the morphology. The thickness of carbon coating on D-LiFePO4/C was about 1.7 nm and the content of carbon was 2.48 wt%, according to HRTEM and TG analysis. The electrochemical impedance spectroscopy analysis indicated that the D-LiFePO4/C composite presented the charge-transfer resistance of 68 Ω and Li ion diffusion coefficient of 2.68 x 10(-13) cm2 S(-1), while the single carbon-coated LiFePO4 (S-LiFePO4/C) exhibited 135.5Ω and 4.03 x 10(-14) cm2 S(-1). Especially, the prepared D-LiFePO4/C electrode showed discharge capacities of 102.9 (10C) and 87.1 (20C) mA h g(-1), respectively, with almost no capacity lost after 400 cycles at 10C, which were much better than those of S-LiFePO4/C composite.

  5. A novel cesium hydroxygallophosphate with a layered structure built up of rutile ribbons: CsGa{sub 2}(OH){sub 2}[(PO{sub 4})H(PO{sub 4})

    SciTech Connect

    Lesage, J.; Guesdon, A. . E-mail: anne.guesdon@ensicaen.fr; Raveau, B.

    2006-12-15

    A new cesium gallophosphate, CsGa{sub 2}(OH){sub 2}[(PO{sub 4})H(PO{sub 4})], with an original layer structure has been synthesized by hydrothermal route characterized by single-crystal X-ray diffraction (R=0.0344, R{sub w}=0.0319). Its structure crystallizes in the monoclinic space group P2{sub 1}/a with cell parameters a=16.079(6)A, b=5.9873(12)A, c=4.5033(15)A, {beta}=93.36(4){sup o} and Z=2. It consists of [Ga(OH)PO{sub 4}]{sub {approx}} layers built up of rutile ribbons interconnected through PO{sub 4} tetrahedra. The structure of CsGa{sub 2}(OH){sub 2}[(PO{sub 4})H(PO{sub 4})] is closely related to those of (NH{sub 4})Ga(OH)PO{sub 4} and (en)Ga{sub 2}(OH){sub 2}(PO{sub 4}){sub 2} (en=ethylenediamine [H{sub 3}N(CH{sub 2}){sub 2}NH{sub 3}]{sup 2+}). The three structures differ mainly from each other by the relative positions and the spacing of the successive layers, which are governed by different hydrogen bonding modes between [Ga(OH)PO{sub 4}]{sub {approx}} layers and the interleaved species. The title compound presents strong symmetric hydrogen bonds O-H-O which bridge two PO{sub 4} tetrahedra of two successive layers. As a consequence, the distance between the layers is significantly shorter than in the two other amine compounds.

  6. Removal of FePO4 and Fe3(PO4)2 crystals on the surface of passive fillers in Fe0/GAC reactor using the acclimated bacteria.

    PubMed

    Lai, Bo; Zhou, Yuexi; Yang, Ping; Wang, Juling; Yang, Jinghui; Li, Huiqiang

    2012-11-30

    As past studies presented, there is obvious defect that the fillers in the Fe(0)/GAC reactor begin to be passive after about 60 d continuous running, although the complicated, toxic and refractory ABS resin wastewater can be pretreated efficiently by the Fe(0)/GAC reactor. During the process, the Fe(3)(PO(4))(2) and FePO(4) crystals with high density in the passive film are formed by the reaction between PO(4)(3-) and Fe(2+)/Fe(3+). Meanwhile, they obstruct the formation of macroscopic galvanic cells between Fe(0) and GAC, which will lower the wastewater treatment efficiency of Fe(0)/GAC reactor. In this study, in order to remove the Fe(3)(PO(4))(2) and FePO(4) crystals on the surface of the passive fillers, the bacteria were acclimated in the passive Fe(0)/GAC reactor. According to the results, it can be concluded that the Fe(3)(PO(4))(2) and FePO(4) crystals with high density in the passive film could be decomposed or removed by the joint action between the typical propionic acid type fermentation bacteria and sulfate reducing bacteria (SRB), whereas the PO(4)(3-) ions from the decomposition of the Fe(3)(PO(4))(2) and FePO(4) crystals were released into aqueous solution which would be discharged from the passive Fe(0)/GAC reactor. Furthermore, the remained FeS and sulfur (S) in the passive film also can be decomposed or removed easily by the oxidation of the sulfur-oxidizing bacteria. This study provides some theoretical references for the further study of a cost-effective bio-regeneration technology to solve the passive problems of the fillers in the zero-valent iron (ZVI) or Fe(0)/GAC reactor.

  7. Hydrogen transfer and hydration properties of HnPO43-n (n=0-3) in water studied by first principles molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Tang, Emilia; Di Tommaso, Devis; de Leeuw, Nora H.

    2009-06-01

    Density functional theory Perdew-Burke-Ernzerhof [Perdew et al., Phys. Rev. Lett. 77, 3865 (1996)] molecular dynamics simulations of aqueous solutions of orthophosphate species HnPO43-n (n =0-3) provide new insights into hydrogen transfer and intermolecular and hydration properties of these important aqueous species. Extensive Car-Parrinello molecular dynamics simulations of the orthophosphate ion PO43-, of the hydrogen phosphate anions, HPO42- and H2PO4-, and of the orthophosphoric acid, H3PO4, in explicit water show that the process of proton transfer from HnPO43-n to the surrounding water molecules is very fast, less than 1 ps, and indicate that the dehydrogenation occurs through a concerted proton hopping mechanism, which involves HnPO43-n and three water molecules. Analysis of the intermolecular HnPO43-n-water structure shows that the PO43- anions have a significant effect on the H-bonding network of bulk water and the presence of P-O- moieties induce the formation of new types of H-H interactions around this orthophosphate. Calculated probability distributions of the coordination numbers of the first hydration shell of PO43-, HPO42-, and H2PO4- show that these phosphate species display a flexible first coordination shell (between 7 and 13 water molecules) and that the flexibility increases on going from PO43- to H2PO4-. The strength and number of hydrogen bonds of PO43-, HPO42-, and H2PO4- are determined through a detailed analysis of the structural correlation functions. In particular, the H-bond interactions between the oxygen atoms of the phosphates and the surrounding water molecules, which decrease on going from PO43- to the hydrogenated H2PO4- species, explain the diminished effect on the structure of water with the increasing hydrogenation of the orthophosphate anions.

  8. Electronic states and potential energy surfaces of H2Te, H2Po, and their positive ions

    NASA Astrophysics Data System (ADS)

    Sumathi, K.; Balasubramanian, K.

    1990-06-01

    Geometries, bond energies, ionization potentials, dipole moments, other one-electron properties, and potential energy surfaces of six valence electronic states of H2Te and H2Po species are obtained using the relativistic complete active space multiconfiguration self-consistent field (CASSCF) followed by full second-order configuration interaction (SOCI) and relativistic configuration interaction (RCI) calculations including spin-orbit coupling. In addition, Rydberg states of H2Te and H2Se are studied to interpret the experimental spectra. The potential energy surfaces of two electronic states of H2Te+ and H2Po+ are obtained. The ground states of both H2Te and H2Po are found to be of X 1A1(A1) symmetry with bent (C2v) equilibrium geometries of H2Te:re =1.668 Å, θe=91.2°; and H2Po:re =1.835 Å and θe=90.9°. The ground states of H2Te+ and H2Po+ are X 2B1 with H2Te+:re =1.676 Å, θe=90.7° and H2Po+:re =1.828 Å and θe=88°. The De (HTe-H) and De (HPo-H) including spin-orbit effects are calculated as 63.2 and 39.4 kcal/mol, respectively. The X 2B1(E)-A 2A1(E) energy separations of H2Te+ and H2Po+ ions are calculated as 66.6 and 76 kcal/mol, respectively. The adiabatic IPs of H2Te and H2Po are calculated as 8.47 and 7.79 eV, respectively. In addition CASSCF/SOCI/RCI calculations are also carried out on the X 2Π3/2 and 2Π1/2 states of TeH and PoH diatomics. The X 2Π3/2-2Π1/2 energy separations of TeH and PoH are computed as 3710 and 9920 cm-1, respectively. Spin-orbit effects are thus found to be very significant for PoH and H2Po. All excited states of H2Te and H2Po are above 3.7 and 3.1 eV, respectively. Properties and energy separations of H2Te and H2Po are compared with the lighter group (VI) H2Ch species.

  9. Nuclear shape coexistence in Po isotopes: An interacting boson model study

    NASA Astrophysics Data System (ADS)

    García-Ramos, J. E.; Heyde, K.

    2015-09-01

    Background: The lead region, Po, Pb, Hg, and Pt, shows up the presence of coexisting structures having different deformation and corresponding to different particle-hole configurations in the shell-model language. Purpose: We intend to study the importance of configuration mixing in the understanding of the nuclear structure of even-even Po isotopes, where the shape coexistence phenomena are not clear enough. Method: We study in detail a long chain of polonium isotopes, Po-208190, using the interacting boson model with configuration mixing (IBM-CM). We fix the parameters of the Hamiltonians through a least-squares fit to the known energies and absolute B (E 2 ) transition rates of states up to 3 MeV. Results: We obtained the IBM-CM Hamiltonians and we calculate excitation energies, B (E 2 ) 's, electric quadrupole moments, nuclear radii and isotopic shifts, quadrupole shape invariants, wave functions, and deformations. Conclusions: We obtain a good agreement with the experimental data for all the studied observables and we conclude that shape coexistence phenomenon is hidden in Po isotopes, very much as in the case of the Pt isotopes.

  10. Increase of 210Po levels in human semen fluid after mussel ingestion.

    PubMed

    Kelecom, Alphonse; Gouvea, Rita de Cássia dos Santos

    2011-05-01

    Polonium-210 ((210)Po) radioactive concentrations were determined in human semen fluid of vasectomized non-smoker volunteers. The (210)Po levels ranged from 0.10 to 0.39 mBq g(-1) (mean: 0.23 ± 0.08 mBq g(-1)). This value decreased to 0.10 ± 0.02 mBq g(-1) (range from 0.07 to 0.13 mBq g(-1)) after two weeks of a controlled diet, excluding fish and seafood. Then, volunteers ate during a single meal 200 g of the cooked mussel Perna perna L., and (210)Po levels were determined again, during ten days, in semen fluid samples collected every morning. Volunteers continued with the controlled diet and maintained sexual abstinence through the period of the experiment. A 300% increase of (210)Po level was observed the day following mussel consumption, with a later reduction, such that the level returned to near baseline by day 4.

  11. Near-infrared Downconversion in LuPO4: Tm3+, Yb3+ Phosphors.

    PubMed

    Li, Li; Wang, Yongjie; Shen, Jun; Chang, Wenxuan; Jin, Tianting; Wei, Xiantao; Tian, Ya

    2016-04-01

    Tm3+ and Yb3+ codoped LuPO4 phosphors were synthesized by the reverse-strike co-precipitation method. The obtained LuPO4:Tm3+,Yb3+ phosphors were characterized by X-ray diffraction (XRD), diffuse reflectance spectra, photoluminescence (PL) spectra, and decay lifetime to understand the observed near-infrared downconversion (DC) phenomena. The XRD results show that all the prepared phosphors can be readily indexed to the pure tetragonal phase of LuPO4 and exhibit good crystallinity. The experimental results showed that the strong visible emission around 649 nm from Tm3+(1G4 --> 3F4) and near-infrared (NIR) emission around 1003 nm from Yb3+(2F5/2 --> 2F7/2) of LuPO4:Tm3+,Yb3+ phosphors were observed under 468 nm excitation, respectively. The Yb3+ concentration dependence of luminescent properties and lifetimes of both the visible and NIR emissions have also been investigated. The quenching concentration of Yb3+ ions approaches 30 mol%. The DC mechanism is also discussed in detail. PMID:27451658

  12. Comparison of the electronic structures of four crystalline forms of FePO4.

    NASA Astrophysics Data System (ADS)

    Tang, Ping

    2005-03-01

    The purpose of this study is to investigate the stability of FePO4, the fully charged form of the Li ion battery material, LiFePO4. The electronic structures of four phases of FePO4, having the CrVO4,ootnotetextJ. P. Attfield and co-workers, J. Solid State Chem. 57, 357 (1985) quartz,ootnotetextH. N. Ng and C. Calvo, Can. J. Chem. 53, 2064 (1975) monoclinic,ootnotetext Y. Song and co-workers, Inorg. Chem. 41, 5778 (2002) and olivineootnotetextA. S. Andersson and co-workers, Solid State Ionics 130, 41 (2000) structures are studied using density functional theory with LSDA and GGA exchange-correlation functionals. A ferromagnetic spin configuration is chosen for all of the FePO4 calculations. The band structures, density of states, and total energies are compared among all four phases. The results show that the CrVO4 phase is metallic while the other phases are insulating. The band gaps of the insulating phases are found to increase with decreasing density of the material.

  13. Enhanced E1 transitions and {alpha}-clustering in {sup 212}Po

    SciTech Connect

    Suzuki, Y.; Ohkubo, S.

    2011-05-06

    An {alpha}+{sup 208}Pb(0{sup +},3{sup -}) cluster model explains the recently observed enhanced E1 transitions from the new negative-parity levels to the yrast states in {sup 212}Po. Heavy and light nuclei present good examples of surface clustering and well-localized clustering.

  14. Mesoscale phase distribution in single particles of LiFePO4 following lithium deintercalation.

    PubMed

    Boesenberg, Ulrike; Meirer, Florian; Liu, Yijin; Shukla, Alpesh K; Dell'anna, Rossana; Tyliszczak, Tolek; Chen, Guoying; Andrews, Joy C; Richardson, Thomas J; Kostecki, Robert; Cabana, Jordi

    2013-05-14

    The chemical phase distribution in hydrothermally grown micrometric single crystals LiFePO4 following partial chemical delithiation was investigated. Full field and scanning X-ray microscopy were combined with X-ray absorption spectroscopy at the Fe K- and O K-edges, respectively, to produce maps with high chemical and spatial resolution. The resulting information was compared to morphological insight into the mechanics of the transformation by scanning transmission electron microscopy. This study revealed the interplay at the mesocale between microstructure and phase distribution during the redox process, as morphological defects were found to kinetically determine the progress of the reaction. Lithium deintercalation was also found to induce severe mechanical damage in the crystals, presumably due to the lattice mismatch between LiFePO4 and FePO4. Our results lead to the conclusion that rational design of intercalation-based electrode materials, such as LiFePO4, with optimized utilization and life requires the tailoring of particles that minimize kinetic barriers and mechanical strain. Coupling TXM-XANES with TEM can provide unique insight into the behavior of electrode materials during operation, at scales spanning from nanoparticles to ensembles and complex architectures. PMID:23745016

  15. Mesoscale phase distribution in single particles of LiFePO4 following lithium deintercalation

    PubMed Central

    Boesenberg, Ulrike; Meirer, Florian; Liu, Yijin; Shukla, Alpesh K.; Dell’Anna, Rossana; Tyliszczak, Tolek; Chen, Guoying; Andrews, Joy C.; Richardson, Thomas J.; Kostecki, Robert; Cabana, Jordi

    2013-01-01

    The chemical phase distribution in hydrothermally grown micrometric single crystals LiFePO4 following partial chemical delithiation was investigated. Full field and scanning X-ray microscopy were combined with X-ray absorption spectroscopy at the Fe K- and O K-edges, respectively, to produce maps with high chemical and spatial resolution. The resulting information was compared to morphological insight into the mechanics of the transformation by scanning transmission electron microscopy. This study revealed the interplay at the mesocale between microstructure and phase distribution during the redox process, as morphological defects were found to kinetically determine the progress of the reaction. Lithium deintercalation was also found to induce severe mechanical damage in the crystals, presumably due to the lattice mismatch between LiFePO4 and FePO4. Our results lead to the conclusion that rational design of intercalation-based electrode materials, such as LiFePO4, with optimized utilization and life requires the tailoring of particles that minimize kinetic barriers and mechanical strain. Coupling TXM-XANES with TEM can provide unique insight into the behavior of electrode materials during operation, at scales spanning from nanoparticles to ensembles and complex architectures. PMID:23745016

  16. Metal content in river suspended particulate matter: data on Po River.

    PubMed

    Blo, Gabriella; Conato, Chiara; Contado, Catia; Fagioli, Francesco; Vaccaro, Carmela; Dondi, Francesco

    2004-01-01

    The present study summarizes the last ten years of literature on heavy metal distribution in Suspended Particulate Matter (SPM) and dissolved phase in the Po River (Italy). The work compares different methodologies employed to collect, concentrate and fractionate the samples. The importance of metal speciation as a function of particle size is underlined and two approaches to metal speciation in the colloidal fraction of Po River SPM are presented: Sedimentation Field-Flow Fractionation (SdFFF) and pH-dependent extractions. Finally, emphasis is placed on the need for comparison with a reference "natural background level" of the metal load in Po River particulate matter in order to determine the real human contribution to river pollution. The high values of some trace transition elements, such as Cr and Ni, have been compared with clay sediments around Ferrara and with bricks in historic buildings. The highly comparable natural concentration of these metals in Po fine sedimentary rocks and in historic brick buildings of Ferrara (XII-XVI centuries) can provide information on natural geochemical anomalies.

  17. Phosphorus-bearing molecules in solar-type star forming regions: First PO detection.

    NASA Astrophysics Data System (ADS)

    Lefloch, Bertrand; Vastel, C.; Viti, S.; Jimenez-Serra, I.; Codella, C.; Podio, L.; Ceccarelli, C.; Mendoza, E.; Lepine, J. R. D.; Bachiller, R.

    2016-08-01

    As part of the Large Program ASAI (Astrochemical Surveys At IRAM), we have used the IRAM 30m telescope to lead a systematic search for the emission of rotational transitions of P-bearing species between 80 and 350 GHz towards L1157-B1, a shock position in the solar-type star forming region L1157. We report the detection of several transitions of PN and, for the first time, of prebiotic molecule PO. None of these species are detected towards the driving protostar of the outflow L1157-mm. Analysis of the line profiles shows that PN arises from the outflow cavity, where SiO, a strong shock tracer, is produced. Radiative transfer analysis yields an abundance of 2.5 × 10-9 and 0.9 × 10-9 for PO and PN, respectively. These results imply a strong depletion (≈100) of Phosphorus in the quiescent cloud gas. Shock modelling shows that atomic N plays a major role in the chemistry of PO and PN. The relative abundance of PO and PN brings constraints both on the duration of the pre-shock phase, which has to be ˜ 106 yr, and on the shock parameters. The maximum temperature in the shock has to be larger than 4000 K, which implies a shock velocity of 40 km s-1.

  18. Electronic structure and optical properties of TbPO4: Experiment and density functional theory calculations

    NASA Astrophysics Data System (ADS)

    Khadraoui, Z.; Horchani-Naifer, K.; Ferhi, M.; Ferid, M.

    2015-09-01

    Single crystals of TbPO4 were grown by high temperature solid-state reaction and identified by means of X-ray diffraction, infrared and Raman spectroscopies analysis. The electronic properties of TbPO4 such as the energy band structures, density of states were carried out using density functional theory (DFT). We have employed the LDA+U functional to treat the exchange correlation potential by solving Kohn-Sham equation. The calculated total and partial density of states indicate that the top of valance band is mainly built upon O-2p states and the bottom of the conduction band mostly originates from Tb-5d states. The population analysis indicates that the P-O bond was mainly covalent and Tb-O bond was mainly ionic. The emission spectrum, color coordinates and decay curve were employed to reveal the luminescence properties of TbPO4. Moreover, the optical properties including the dielectric function, absorption spectrum, refractive index, extinction coefficient, reflectivity and energy-loss spectrum are investigated and analyzed. The results are discussed and compared with the available experimental data.

  19. Phosphorus-bearing molecules in solar-type star-forming regions: first PO detection

    NASA Astrophysics Data System (ADS)

    Lefloch, Bertrand; Vastel, C.; Viti, S.; Jimenez-Serra, I.; Codella, C.; Podio, L.; Ceccarelli, C.; Mendoza, E.; Lepine, J. R. D.; Bachiller, R.

    2016-11-01

    As part of the Large Program Astrochemical Surveys At IRAM, we have used the IRAM 30 m telescope to lead a systematic search for the emission of rotational transitions of P-bearing species between 80 and 350 GHz towards L1157-B1, a shock position in the solar-type star-forming region L1157. We report the detection of several transitions of PN and, for the first time, of pre-biotic molecule PO. None of these species are detected towards the driving protostar of the outflow L1157-mm. Analysis of the line profiles shows that PN arises from the outflow cavity, where SiO, a strong shock tracer, is produced. Radiative transfer analysis yields an abundance of 2.5 × 10-9 and 0.9 × 10-9 for PO and PN, respectively. These results imply a strong depletion (≈100) of phosphorus in the quiescent cloud gas. Shock modelling shows that atomic N plays a major role in the chemistry of PO and PN. The relative abundance of PO and PN brings constraints both on the duration of the pre-shock phase, which has to be ˜106 yr, and on the shock parameters. The maximum temperature in the shock has to be larger than 4000 K, which implies a shock velocity of 40 km s-1.

  20. CdZnTe Background Measurements at Balloon Altitudes with PoRTIA

    NASA Technical Reports Server (NTRS)

    Parsons, A.; Barthelmy, S.; Bartlett, L.; Gehrels, N.; Naya, J.; Stahle, C. M.; Tueller, J.; Teegarden, B.

    2003-01-01

    Measurements of the CdZnTe internal background at balloon altitudes are essential to determine which physical processes make the most important background contributions. We present results from CdZnTe background measurements made by PoRTIA, a small CdZnTe balloon instrument that was flown three times in three different shielding configurations. PoRTIA was passively shielded during its first flight from Palestine, Texas and actively shielded as a piggyback instrument on the GRIS balloon experiment during its second and third flights from Alice Springs, Australia, using the thick GRIS Nal anticoincidence shield. A significant CdZnTe background reduction was achieved during the third flight with PoRTIA placed completely inside the GRIS shield and blocking crystal, and thus completely surrounded by 15 cm of Nal. A unique balloon altitude background data set is provided by CdZnTe and Ge detectors simultaneously surrounded by the same thick anticoincidence shield; the presence of a single coxial Ge detector inside the shield next to PoRTIA allowed a measurement of the ambient neutron flux inside the shield throughout the flight. These neutrons interact with the detector material to produce isomeric states of the Cd, Zn and Te nuclei that radiatively decay; calculations are presented that indicate that these decays may explain most of the fully shielded CdZnTe background.

  1. The Aalborg University PO-PBL Model from a Socio-Cultural Learning Perspective

    ERIC Educational Resources Information Center

    Hernandez, Carola; Ravn, Ole; Valero, Paola

    2015-01-01

    Since the 1970s, Aalborg University has been developing a new pedagogical model in higher education: The Project Oriented-Problem Based Learning (PO-PBL). In particular, the Faculty of Engineering and Science has developed a pedagogical proposal that introduces students to a different type of learning. One of the theoretical frameworks…

  2. 21 CFR 868.1200 - Indwelling blood oxygen partial pressure (PO2) analyzer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Indwelling blood oxygen partial pressure (PO2) analyzer. 868.1200 Section 868.1200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices §...

  3. 21 CFR 868.1200 - Indwelling blood oxygen partial pressure (PO2) analyzer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Indwelling blood oxygen partial pressure (PO2) analyzer. 868.1200 Section 868.1200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices §...

  4. 21 CFR 868.1200 - Indwelling blood oxygen partial pressure (PO2) analyzer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Indwelling blood oxygen partial pressure (PO2) analyzer. 868.1200 Section 868.1200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices §...

  5. 21 CFR 868.1200 - Indwelling blood oxygen partial pressure (PO2) analyzer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Indwelling blood oxygen partial pressure (PO2) analyzer. 868.1200 Section 868.1200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices §...

  6. 21 CFR 868.1200 - Indwelling blood oxygen partial pressure (PO2) analyzer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Indwelling blood oxygen partial pressure (PO2) analyzer. 868.1200 Section 868.1200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices §...

  7. Hydrothermal preparation of LiFePO 4 nanocrystals mediated by organic acid

    NASA Astrophysics Data System (ADS)

    Ni, Jiangfeng; Morishita, Masanori; Kawabe, Yoshiteru; Watada, Masaharu; Takeichi, Nobuhiko; Sakai, Tetsuo

    Well-crystallized LiFePO 4 nanoparticles have been directly synthesized in a short time via hydrothermal process in the presence of organic acid, e.g. citric acid or ascorbic acid. These acid-mediated LiFePO 4 products exhibit a phase-pure and nanocrystal nature with size about 50-100 nm. Two critical roles that the organic acid mediator plays in hydrothermal process are recognized and a rational mechanism is explored. After a post carbon-coating treatment at 600 °C for 1 h, these mediated LiFePO 4 materials show a high electrochemical activity in terms of reversible capacity, cycling stability and rate capability. Particularly, LiFePO 4 mediated by ascorbic acid can deliver a capacity of 162 mAh g -1 at 0.1 C, 154 mAh g -1 at 1 C, and 122 mAh g -1 at 5 C. The crystalline structure, particle morphology, and surface microstructure were characterized by high-energy synchrotron X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM), and Raman spectroscopy, respectively. And the electrochemical properties were thoroughly investigated by galvanostatic test and electrochemical impedance spectroscopy (EIS).

  8. High-pressure synthesis and crystal structure of silicon phosphate hydroxide, SiPO 4(OH)

    NASA Astrophysics Data System (ADS)

    Stearns, Linda A.; Groy, Thomas L.; Leinenweber, Kurt

    2005-09-01

    A new high-pressure phase, silicon phosphate hydroxide, was prepared at 8.3±0.5 GPa and 1000 °C in >98% purity. From X-ray diffraction on a pseudo-merohedrally twinned crystal, it was found that SiPO 4(OH) crystallizes in a monoclinic cell with space group P21/n (No. 14), a=6.8446(11) Å, b=6.8683(13) Å, c=6.8446(11) Å, β=119.77(1)∘, and Z=4. The refinement gave a conventional Robs of 0.0320 and wRobs of 0.0864 for the overlapped data from both twin components. In the structure, SiO 6 octahedra form chains along [101], with PO 4 tetrahedra alternating along the chain in the b-direction. The parallel chains link up with tetrahedral corners from other chains to form a 3-dimensional network. SiPO 4(OH) belongs to a structural family that includes HgSeO4·H2O. It is also related to the SbOPO 4 structure by a small distortion that lowers the symmetry from C2/c in SbOPO 4 to P21/c (P21/n) in SiPO 4(OH).

  9. 76 FR 54931 - Post Office (PO) Box Fee Groups for Merged Locations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-06

    ... FR 40849-40850), requesting comments to allow the Postal Service to change the fee group assignment for PO Boxes by more than one level (higher or lower) when boxes move to a different ZIP Code TM... into one location, a ZIP Code may be moved only into the next higher or lower fee group. If boxes...

  10. Ab-initio Calculation of the XANES of Lithium Phosphates and LiFePO4

    NASA Astrophysics Data System (ADS)

    Yiu, Y. M.; Yang, Songlan; Wang, Dongniu; Sun, Xueliang; Sham, T. K.

    2013-04-01

    Lithium iron phosphate has been regarded as a promising cathode material for the next generation lithium ion batteries due to its high specific capacity, superior thermal and cyclic stability [1]. In this study, the XANES (X-ray Absorption Near Edge Structure) spectra of lithium iron phosphate and lithium phosphates of various compositions at the Li K, P L3,2, Fe M3,2 and O K-edges have been simulated self-consistently using ab-initio calculations based on multiple scattering theory (the FEFF9 code) and DFT (Density Functional Theory, the Wien2k code). The lithium phosphates under investigation include LiFePO4, γ-Li3PO4, Li4P2O7 and LiPO3. The calculated spectra are compared to the experimental XANES recorded in total electron yield (TEY) and fluorescence yield (FLY). This work was carried out to assess the XANES of possible phases presented in LiFePO4 based Li ion battery applications [2].

  11. Phase boundary propagation in large LiFePO4 single crystals on delithiation.

    PubMed

    Weichert, Katja; Sigle, Wilfried; van Aken, Peter A; Jamnik, Janez; Zhu, Changbao; Amin, Ruhul; Acartürk, Tolga; Starke, Ulrich; Maier, Joachim

    2012-02-15

    Large single crystals of LiFePO(4) have been chemically delithiated. The relevance of chemical oxidation in comparison with electrochemical delithiation is discussed. Analyses of the Li content and profiles were done by electron energy loss spectroscopy and secondary ion mass spectrometry. The propagation of the FePO(4) phase growing on the surface of the large single crystal was followed by in situ optical microscopy as a function of time. The kinetics were evaluated in terms of linear irreversible thermodynamics and found to be characterized by an induction period followed by parabolic growth behavior of the FePO(4) phase indicating transport control. The growth rate was shown to depend on the crystallographic orientation. Scanning electron microscopy images showed cracks and a high porosity of the FePO(4) layer due to the significant changes in the molar volumes. The transport was found to be greatly enhanced by the porosity and crack formation and hence greatly enhanced over pure bulk transport, a result which is supposed to be very relevant for battery research if coarse-grained powder is used.

  12. Diffusion and possible freezing phases of Li-ions in LiFePO4

    NASA Astrophysics Data System (ADS)

    Yiu, Yuen; Toft-Petersen, Rasmus; Ehlers, Georg; Vaknin, David

    Elastic and inelastic neutron scattering studies of LiFePO4 single crystal reveal new Li-ion diffusion properties relevant to its function as Li-battery materials. In the past decade there has been broad interest in LiFePO4 and its related compounds, largely due to the applications of these materials as cathodes in Li- batteries. This is owing to these materials' high charge-discharge ability and conductivity, both of which are by virtue of the Li-ions' high mobility. In this talk, we present our findings on the temperature and directional dependence of Li-ions' diffusion in LiFePO4. LiFePO4 adopts the olivine structure at room temperature (Space group: Pnma), which contains channels along principal crystalline directions that allow Li-ion motion. Elastic neutron scattering reveals lowering of symmetry from the Pnma structure below room temperature, which can be interpreted as the freezing of Li-ions, and can be subsequently linked to the reported decrease in Li-ion conductivity. Inelastic neutron scattering, in the 35K to 720K temperature range, shows temperature dependence, as well as anisotropy (i.e. along 0K0 versus 00L) of Li-ion diffusion. Ames Laboratory is supported by U.S. DOE, BES, DMSE, under Contract #DE-AC02-07CH11358. Spallation Neutron Source of Oak Ridge National Laboratory is sponsored by U.S. DOE, BES, SUFD.

  13. Cycling stability and degradation mechanism of LiMnPO4 based electrodes

    NASA Astrophysics Data System (ADS)

    Moskon, J.; Pivko, M.; Jerman, I.; Tchernychova, E.; Logar, N. Zabukovec; Zorko, M.; Selih, V. S.; Dominko, R.; Gaberscek, M.

    2016-01-01

    Long term stability of LiMnPO4 particles with a crystallite size between ˜20 and 50 nm covered with a dense native carbon coating (14 wt.%) is demonstrated. More than 500 cycles at a rate of C/20, in the potential window of 2.7-4.5 V and a temperature of 55 °C were achieved. During most of the cycling the average capacity decay was less than 0.06% per cycle. After about 500 cycles a sudden capacity drop was observed. Degradation processes in various stages of cycling were thoroughly examined using a range of techniques. Severe surface film formation, manganese dissolution and degradation of LixMnPO4 accompanied by formation of Li4P2O7 were clearly identified. The good long term stability seems to be due to dense, protective carbon coating. Decomposition is most likely initiated at local defects in the microstructure of pyrolytic carbon coating around LiMnPO4 particles. In addition to known degradation mechanisms of LiMnPO4 we observed pronounced gradual amorphization of the olivine crystallites during long-term cycling at 55 °C. Finally, changes in morphology of the carbon black additive after prolonged cycling are reported and commented.

  14. Temperature Dependence of Aliovalent-vanadium Doping in LiFePO4 Cathodes

    SciTech Connect

    Harrison, Katharine L; Bridges, Craig A; Paranthaman, Mariappan Parans; Idrobo Tapia, Juan C; Manthiram, Arumugam; Goodenough, J. B.; Segre, C; Katsoudas, John; Maroni, V. A.

    2013-01-01

    Vanadium-doped olivine LiFePO4 cathode materials have been synthesized by a novel low-temperature microwave-assisted solvothermal (MW-ST) method at 300 oC. Based on chemical and powder neutron/X-ray diffraction analysis, the compositions of the synthesized materials were found to be LiFe1-3x/2Vx x/2PO4 (0 x 0.2) with the presence of a small number of lithium vacancies charge-compensated by V4+, not Fe3+, leading to an average oxidation state of ~ 3.2+ for vanadium. Heating the pristine 15 % V-doped sample in inert or reducing atmospheres led to a loss of vanadium from the olivine lattice with the concomitant formation of a Li3V2(PO4)3 impurity phase; after phase segregation, a partially V-doped olivine phase remained. For comparison, V-doped samples were also synthesized by conventional ball milling and heating, but only ~ 10 % V could be accommodated in the olivine lattice in agreement with previous studies. The higher degree of doping realized with the MW-ST samples demonstrates the temperature dependence of the aliovalent-vanadium doping in LiFePO4.

  15. Linking the Fits, Fitting the Links: Connecting Different Types of PO Fit to Attitudinal Outcomes

    ERIC Educational Resources Information Center

    Leung, Aegean; Chaturvedi, Sankalp

    2011-01-01

    In this paper we explore the linkages among various types of person-organization (PO) fit and their effects on employee attitudinal outcomes. We propose and test a conceptual model which links various types of fits--objective fit, perceived fit and subjective fit--in a hierarchical order of cognitive information processing and relate them to…

  16. The First Detections of the Key Prebiotic Molecule PO in Star-forming Regions

    NASA Astrophysics Data System (ADS)

    Rivilla, V. M.; Fontani, F.; Beltrán, M. T.; Vasyunin, A.; Caselli, P.; Martín-Pintado, J.; Cesaroni, R.

    2016-08-01

    Phosphorus is a crucial element in biochemistry, in particular the P-O bond, which is key in the formation of the backbone of deoxyribonucleic acid. So far, PO has only been detected toward the envelope of evolved stars, but never toward star-forming regions. We report the first detection of PO toward two massive star-forming regions, W51 e1/e2 and W3(OH), using data from the IRAM 30 m telescope. PN has also been detected toward the two regions. The abundance ratio PO/PN is 1.8 and 3 for W51 and W3(OH), respectively. Our chemical model indicates that the two molecules are chemically related and are formed via gas-phase ion-molecule and neutral-neutral reactions during cold collapse. The molecules freeze out onto grains at the end of the collapse and desorb during the warm-up phase once the temperature reaches ˜35 K. Similar abundances of the two species are expected during a period of ˜5 × 104 yr at the early stages of the warm-up phase, when the temperature is in the range 35-90 K. The observed molecular abundances of 10-10 are predicted by the model if a relatively high initial abundance of 5 × 10-9 of depleted phosphorus is assumed.

  17. Dosimetry of {sup 210}Po in humans, caribou, and wolves in northern Canada

    SciTech Connect

    Thomas, P.A.

    1994-06-01

    Effective doses from {sup 210}Po intake with caribou meat were determined for human residents in Baker Lake and Snowdrift in the Northwest Territories of Canada and compared to doses calculated from reported {sup 210}Po tissue activities in Alaskan and British residents. Effective doses were calculated to separate body tissues, using ICRP 60 human weighting factors and the ICRP 30 metabolic model for {sup 210}Po. Baker Lake and Alaskan effective doses were similar at 0.4 mSv y{sup {minus}1} and slightly higher than Snowdrift doses (0.3 mSv y{sup {minus}1}). Alaskan tissue activities indicated higher effective doses to liver, bone surfaces and red marrow and lower doses to spleen than the {sup 210}Po metabolic model (ICRP 1979a) predicts. Effective doses to Baker Lake and Snowdrift caribou and wolves, calculated from tissue activities, ranged from 7-20 mSv y{sup {minus}1} using human weighting factors for comparison to human doses only. Effective doses to northern Canadians and wildlife were, respectively, 7-11% and 1.8-5 times an estimated human background of 4 mSv y{sup {minus}} from all sources. 51 refs., 2 figs., 9 tabs.

  18. CWM PO*WW*ER™ EVAPORATION-CATALYTIC OXIDATION TECHNOLOGY - APPLICATIONS ANALYSIS REPORT

    EPA Science Inventory

    This report evaluates the Chemical Waste Management, Inc. (CWM), PO*WW*ER™ technology’s ability to remove volatile organic compounds (VOC), semivolatile organic compounds (SVOC), ammonia, cyanide, metals, and other inorganic contaminants from aqueous wastes. This evaluation is ba...

  19. Use of industrial byproducts to filter PO43- and pesticides in golf green drainage water

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Golf courses are vulnerable to phosphate (PO43-) and pesticide loss by infiltration because of the sandy, porous grass rooting media used and presence of subsurface tile drainage. In this study, a blend of industrial byproducts, including granulated blast furnace slag (GBFS), cement kiln dust (CKD),...

  20. Near-infrared Downconversion in LuPO4: Tm3+, Yb3+ Phosphors.

    PubMed

    Li, Li; Wang, Yongjie; Shen, Jun; Chang, Wenxuan; Jin, Tianting; Wei, Xiantao; Tian, Ya

    2016-04-01

    Tm3+ and Yb3+ codoped LuPO4 phosphors were synthesized by the reverse-strike co-precipitation method. The obtained LuPO4:Tm3+,Yb3+ phosphors were characterized by X-ray diffraction (XRD), diffuse reflectance spectra, photoluminescence (PL) spectra, and decay lifetime to understand the observed near-infrared downconversion (DC) phenomena. The XRD results show that all the prepared phosphors can be readily indexed to the pure tetragonal phase of LuPO4 and exhibit good crystallinity. The experimental results showed that the strong visible emission around 649 nm from Tm3+(1G4 --> 3F4) and near-infrared (NIR) emission around 1003 nm from Yb3+(2F5/2 --> 2F7/2) of LuPO4:Tm3+,Yb3+ phosphors were observed under 468 nm excitation, respectively. The Yb3+ concentration dependence of luminescent properties and lifetimes of both the visible and NIR emissions have also been investigated. The quenching concentration of Yb3+ ions approaches 30 mol%. The DC mechanism is also discussed in detail.

  1. Synthesis, characterization and observation of antisite defects in LiNiPO4 nanomaterials

    NASA Astrophysics Data System (ADS)

    Kempaiah Devaraju, Murukanahally; Duc Truong, Quang; Hyodo, Hiroshi; Sasaki, Yoshikazu; Honma, Itaru

    2015-06-01

    Structural studies of high voltage cathode materials are necessary to understand their chemistry to improve the electrochemical performance for applications in lithium ion batteries. LiNiPO4 nanorods and nanoplates are synthesized via a one pot synthesis using supercritical fluid process at 450 oC for 10 min. The X-ray diffraction (XRD) analysis confirmed that LiNiPO4 phase is well crystallized, phase purity supported by energy dispersive spectroscopy (EDS) and elemental mapping by scanning electron transmission electron microscopy (STEM). For the first time, we have carried out direct visualization of atom-by-atom structural observation of LiNiPO4 nanomaterials using high-angle annular dark-field (HAADF) and annular bright-field (ABF) scanning transmission electron microscopy (STEM) analysis. The Rietveld refinement analysis was performed to find out the percentage of antisite defects presents in LiNiPO4 nanoplates and about 11% of antisite defects were found. Here, we provide the direct evidence for the presence of Ni atoms in Li sites and Li in Ni sites as an antisite defects are provided for understanding of electrochemical behavior of high voltage Li ion battery cathode materials.

  2. Synthesis, characterization and observation of antisite defects in LiNiPO4 nanomaterials

    PubMed Central

    Kempaiah Devaraju, Murukanahally; Duc Truong, Quang; Hyodo, Hiroshi; Sasaki, Yoshikazu; Honma, Itaru

    2015-01-01

    Structural studies of high voltage cathode materials are necessary to understand their chemistry to improve the electrochemical performance for applications in lithium ion batteries. LiNiPO4 nanorods and nanoplates are synthesized via a one pot synthesis using supercritical fluid process at 450 oC for 10 min. The X-ray diffraction (XRD) analysis confirmed that LiNiPO4 phase is well crystallized, phase purity supported by energy dispersive spectroscopy (EDS) and elemental mapping by scanning electron transmission electron microscopy (STEM). For the first time, we have carried out direct visualization of atom-by-atom structural observation of LiNiPO4 nanomaterials using high-angle annular dark-field (HAADF) and annular bright-field (ABF) scanning transmission electron microscopy (STEM) analysis. The Rietveld refinement analysis was performed to find out the percentage of antisite defects presents in LiNiPO4 nanoplates and about 11% of antisite defects were found. Here, we provide the direct evidence for the presence of Ni atoms in Li sites and Li in Ni sites as an antisite defects are provided for understanding of electrochemical behavior of high voltage Li ion battery cathode materials. PMID:26091441

  3. Improving thermal stability of KSrPO4:Tb3+ phosphors prepared by microwave assisted sintering

    NASA Astrophysics Data System (ADS)

    Peng, Yu-Ming; Su, Yan-Kuin; Yang, Ru-Yuan

    2013-10-01

    In this paper, KSr0.94PO4:Tb0.063+ phosphor was synthesized successfully by microwave assisted sintering method at 1200 °C for 1 h under an air atmosphere. Photoluminescence results show KSr0.94PO4:Tb0.063+ phosphor prepared by microwave assisted sintering method presents an observable improved effect on the enhancement of thermal stability. The emission intensity reduces slowly and marginally by approximately 7% for the maximum emission peak with the temperature increasing from 30 °C to 200 °C indicating great thermal stability KSrPO4:Tb3+ phosphors are. Additionally, the activation energy (ΔE) of thermal quenching of KSrPO4:Tb3+ phosphor was calculated to be 0.2 eV. Moreover, the chromaticity (x, y) located at (0.30, 0.52) was kept without variation when the temperature increased from 30 °C to 200 °C.

  4. A chemically activated graphene-encapsulated LiFePO4 composite for high-performance lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Ha, Jeonghyun; Park, Seung-Keun; Yu, Seung-Ho; Jin, Aihua; Jang, Byungchul; Bong, Sungyool; Kim, In; Sung, Yung-Eun; Piao, Yuanzhe

    2013-08-01

    A composite of modified graphene and LiFePO4 has been developed to improve the speed of charging-discharging and the cycling stability of lithium ion batteries using LiFePO4 as a cathode material. Chemically activated graphene (CA-graphene) has been successfully synthesized via activation by KOH. The as-prepared CA-graphene was mixed with LiFePO4 to prepare the composite. Microscopic observation and nitrogen sorption analysis have revealed the surface morphologies of CA-graphene and the CA-graphene/LiFePO4 composite. Electrochemical properties have also been investigated after assembling coin cells with the CA-graphene/LiFePO4 composite as a cathode active material. Interestingly, the CA-graphene/LiFePO4 composite has exhibited better electrochemical properties than the conventional graphene/LiFePO4 composite as well as bare LiFePO4, including exceptional speed of charging-discharging and excellent cycle stability. That is because the CA-graphene in the composite provides abundant porous channels for the diffusion of lithium ions. Moreover, it acts as a conducting network for easy charge transfer and as a divider, preventing the aggregation of LiFePO4 particles. Owing to these properties of CA-graphene, LiFePO4 could demonstrate enhanced and stably long-lasting electrochemical performance.A composite of modified graphene and LiFePO4 has been developed to improve the speed of charging-discharging and the cycling stability of lithium ion batteries using LiFePO4 as a cathode material. Chemically activated graphene (CA-graphene) has been successfully synthesized via activation by KOH. The as-prepared CA-graphene was mixed with LiFePO4 to prepare the composite. Microscopic observation and nitrogen sorption analysis have revealed the surface morphologies of CA-graphene and the CA-graphene/LiFePO4 composite. Electrochemical properties have also been investigated after assembling coin cells with the CA-graphene/LiFePO4 composite as a cathode active material. Interestingly

  5. Porous LiFePO4/C microspheres as high-power cathode materials for lithium ion batteries.

    PubMed

    Sun, Bing; Wang, Ying; Wang, Bei; Kim, Hyun-Soo; Kim, Woo-Seong; Wang, Guoxiu

    2013-05-01

    Porous LiFePO4/C microspheres were synthesized by a novel hydrothermal reaction combined with high-temperature calcinations. The morphology of the prepared material was investigated by field-emission scanning electron microscopy. Porous microspheres with diameters around 1-3 microm were obtained, which consisting of primary LiFePO4 nanoparticles. The electrochemical performances of the as-prepared LiFePO4 microspheres were evaluated by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge cycling. The carbon coated LiFePO4 microspheres showed lower polarization, higher rate capability, and better cycling stability than that of pristine LiFePO4 microspheres, indicating the potential application as the cathode material for high-power lithium ion batteries.

  6. An Improved Method to Determine {sup 210}Pb, {sup 210}Bi and {sup 210}Po in air Aerosol Filters

    SciTech Connect

    Miguel, E. G. San; Bolivar, J. P.; Teran, T.

    2008-08-07

    {sup 222}Rn daughters (e.g. {sup 210}Pb, {sup 210}Po, {sup 210}Bi) have been widely used to study a variety of atmospheric processes. Many works in literature about {sup 222}Rn daughters do not specify the way by the activities of these radionuclides are calculated. Besides, {sup 210}Po corrections due to the in-growth of {sup 210}Bi, if taken into account, are not indicated. In this work, the increase in uncertainties of radionuclides activities due to delay between air sampling and radionuclides determinations have been evaluated and the influence of neglecting the contribution of {sup 210}Bi in-growth to {sup 210}Po determination has been estimated. The results indicate that, in general, ignoring the {sup 210}Bi in-growth in {sup 210}Po determinations lead to significant differences (could reach until 100%) between the estimation of {sup 210}Po activity and its true value.

  7. Comparison of TcPO II and StO II using the blood oxygen dissociation curve

    NASA Astrophysics Data System (ADS)

    Wright, Leigh P.; Makhratchev, Marina; Yarbrough, Amy; Elmandjra, Mohamed; Mao, Jian-min

    2006-02-01

    It is well known that the relation between the partial pressure of oxygen in blood (PO II) and the hemoglobin oxygen saturation in blood (SO II) is given by the oxyhemoglobin dissociation curve. In this study, we investigate if a similar relation exists in tissue. The PO II in tissue was approximated by the transcutaneous partial pressure of oxygen (TcPO II) measured by TCM3 TM Transcutanous pO II/pCO II Monitoring System; and the SO II in tissue (StO II) was measured by ODISsey TM Tissue Oximeter. The study showed that the TcPO II versus StO II relation is similar to the dissociation curve in blood, as expected.

  8. Improved battery performance using Pd nanoparticles synthesized on the surface of LiFePO4/C by ultrasound irradiation

    NASA Astrophysics Data System (ADS)

    Saliman, Muhammad Ali; Okawa, Hirokazu; Takai, Misaki; Ono, Yuki; Kato, Takahiro; Sugawara, Katsuyasu; Sato, Mineo

    2016-07-01

    LiFePO4 has been attracting interest as a cathode material for Li-ion batteries due to its high energy density, low cost, and eco-friendliness. The electrochemical performance of LiFePO4 is limited because it exhibits low Li-ion diffusivity and low electronic conductivity. Numerous solutions have been considered, such as carbon coating, which is widely known to improve the electronic conductivity of LiFePO4. The deposition of metal nanoparticles (NPs) on the surface of carbon-coated LiFePO4 further enhances the electronic conductivity. In this study, we deposited Pd NPs onto the surface of LiFePO4/C and investigated the resulting electrochemical performance. Sonochemical synthesis was used to prepare the metal NPs; the procedure did not require any surfactants and the reaction was rapid.

  9. Experimental and theoretical studies on the linear and nonlinear optical properties of lead phosphate crystals LiPbPO4.

    PubMed

    Han, Guopeng; Liu, Qiong; Wang, Ying; Su, Xin; Yang, Zhihua; Pan, Shilie

    2016-07-28

    Phosphates with noncentrosymmetric (NCS) structures usually display short ultraviolet (UV) cut-off edges, but often exhibit weak powder second harmonic generation (SHG) intensities. Here we synthesized a NCS-phosphate, LiPbPO4, that achieves a desired balance between UV transparency, a cut-off edge of about 232 nm, and large SHG activity (about 3 × KDP). The three dimensional (3D) framework of LiPbPO4 consists of PO4 and LiO4 tetrahedra that are corner-shared, forming wide channels where lead cations reside. Local dipole moments for the PO4 and LiO4 tetrahedra as well as lead polyhedra in a unit cell were calculated. First-principles calculations have been performed for better understanding the structure-property relationships in LiPbPO4. In addition, to further explore spatial distribution of the electronic states dominating the NLO activity, the SHG density method was employed. PMID:27357234

  10. Hierarchical LiFePO4 with a controllable growth of the (010) facet for lithium-ion batteries

    PubMed Central

    Guo, Binbin; Ruan, Hongcheng; Zheng, Cheng; Fei, Hailong; Wei, Mingdeng

    2013-01-01

    Hierarchically structured LiFePO4 was successfully synthesized by ionic liquid solvothermal method. These hierarchically structured LiFePO4 samples were constructed from nanostructured platelets with their (010) facets mainly exposed. To the best of our knowledge, facet control of a hierarchical LiFePO4 crystal has not been reported yet. Based on a series of experimental results, a tentative mechanism for the formation of these hierarchical structures was proposed. After these hierarchically structured LiFePO4 samples were coated with a thin carbon layer and used as cathode materials for lithium-ion batteries, they exhibited excellent high-rate discharge capability and cycling stability. For instance, a capacity of 95% can be maintained for the LiFePO4 sample at a rate as high as 20 C, even after 1000 cycles. PMID:24071818

  11. Po'ouli landscape bioinformatics models predict energetics, behavior, diets, and distribution on Maui.

    PubMed

    Porter, W P; Vakharia, N; Klousie, W D; Duffy, D

    2006-12-01

    This study uses a spatially explicit microclimate/biophysical approach to examine the potential distribution of the Po'ouli on Maui to find either new habitats to search for existence or refine search efforts in previously occupied areas. We used specific physiological and behavioral ecology bird data, and Po'ouli morphological and spectral data obtained from museum specimens to address ecological and conservation-related questions about the Po'ouli that are otherwise very difficult to quantify. Laboratory and field tested microclimate and biophysical-behavioral animal computer models were integrated with remote sensing technologies. To show that the generic microclimate and endotherm models can predict metabolic and water loss requirements of Hawaiian Honeycreepers, we used the 2 species with known physiological properties, the Hawaiian Amakihi, Hemignathus virens, and the Hawaiian Anianiau, Hemignathus parvus. Predictions were within experimental measurement error of the laboratory measurements. Then using field rather than laboratory conditions as input data, we predict the field distribution of the Amakihi on Maui as the first spatial test of the models applied to birds. Results are consistent with Amakihi field distribution data. Fossils show that the Po'ouli once lived on Maui at low elevations in dry/mesic habitats on a likely diet of native tree snails and insects. The arrival of lethal mosquito-borne avian malaria in Hawaii exterminated low elevation Po'ouli forcing a population shift to mountain rainforests and possibly a snail diet instead of insects. To explore the maximum consequences of such a diet shift we assumed exclusive diets of snails versus insects at both low and high elevations. Snail diets require ∼4 times higher foraging rates than do insect diets, making a predominantly snail diet an unlikely prospect for the Po'ouli. Landscape scale simulations suggest that a snail diet would force a Po'ouli distribution inconsistent with observations

  12. Single crystal X-ray structure study of the Li(2-x)Na(x)Ni[PO4]F system.

    PubMed

    Ben Yahia, Hamdi; Shikano, Masahiro; Koike, Shinji; Tatsumi, Kuniaki; Kobayashi, Hironori

    2012-05-21

    The new compounds Li(2-x)Na(x)Ni[PO(4)]F (x = 0.7, 1, and 2) have been synthesized by a solid state reaction route. Their crystal structures were determined from single-crystal X-ray diffraction data. Li(1.3)Na(0.7)Ni[PO(4)]F crystallizes with the orthorhombic Li(2)Ni[PO(4)]F structure, space group Pnma, a = 10.7874(3), b = 6.2196(5), c = 11.1780(4) Å and Z = 8, LiNaNi[PO(4)]F crystallizes with a monoclinic pseudomerohedrally twinned structure, space group P2(1)/c, a = 6.772(4), b = 11.154(6), c = 5.021(3) Å, β = 90° and Z = 4, and Na(2)Ni[PO(4)]F crystallizes with a monoclinic twinned structure, space group P2(1)/c, a = 13.4581(8), b = 5.1991(3), c = 13.6978(16) Å, β = 120.58(1)° and Z = 8. For x = 0.7 and 1, the structures contain NiFO(3) chains made up of edge-sharing NiO(4)F(2) octahedra, whereas for x = 2 the chains are formed of dimer units (face-sharing octahedra) sharing corners. These chains are interlinked by PO(4) tetrahedra forming a 3D framework for x = 0.7 and different Ni[PO(4)]F layers for x = 1 and 2. A sodium/lithium disorder over three atomic positions is observed in Li(1.3)Na(0.7)Ni[PO(4)]F structure, whereas the alkali metal atoms are well ordered in between the layers in the LiNaNi[PO(4)]F and Na(2)Ni[PO(4)]F structures, which makes both compounds of great interest as potential positive electrodes for sodium cells.

  13. A novel molecular sieve supporting material for enhancing activity and stability of Ag3PO4 photocatalyst

    NASA Astrophysics Data System (ADS)

    Wu, Qiang; Wang, Peifu; Niu, Futao; Huang, Cunping; Li, Yang; Yao, Weifeng

    2016-08-01

    A small-pore silicon-substituted silicon aluminum phosphate (SAPO-34) molecular sieve, for the first time, is reported to significantly increase both the activity and life span of Ag3PO4 photocatalyst for visible-light degradation of methylene blue (MB) and rhodamine B (RhB). Results show that 60 wt.% Ag3PO4/SAPO-34 exhibits the highest photocatalytic degradation efficiencies for both MB (91.0% degradation within 2.0 min) and RhB (91.0% degradation within 7.0 min). In comparison, pure Ag3PO4 powder photocatalyst requires 8.0 min and 12.0 min for decomposing 91.0% of MB and RhB, respectively. During MB degradation the rate constant for 60 wt.% Ag3PO4/SAPO-34 increases 317.2% in comparison with the rate constant of pure Ag3PO4. This activity is also much higher than literature reported composite or supported Ag3PO4 photocatalysts. In three photocatalytic runs for the degradation of RhB, the rate constant for 60 wt.% Ag3PO4/SAPO-34 reduces from 0.33 to 0.18 min-1 (45.5% efficiency loss). In contrast, the rate constant of pure Ag3PO4 catalyst decreases from 0.2 to 0.07 min-1 (80.0% efficiency loss). All experimental results have shown that small pores and zero light absorption loss of SAPO-34 molecular sieves minimize Ag3PO4 loading, enhance photocatalytic activity and prolong the lifespan of Ag3PO4 photocatalyst.

  14. A comparative study of Li8NaV3(P2O7)3(PO4)2 and Li9V3(P2O7)3(PO4)2: Synthesis, structure and electrochemical properties

    NASA Astrophysics Data System (ADS)

    Kuang, Quan; Zhao, Yanming; Dong, Youzhong; Fan, Qinghua; Lin, Xinghao; Liu, Xudong

    2016-02-01

    The energy-density improvement for cathode materials by using the method of occupying the Li site with the lowest formation enthalpy was first presented, and successfully applied to Li9V3(P2O7)3(PO4)2. Herein, the synthesis, structure and electrochemical properties (including both Li extraction and intercalation) of mixed alkali-ion phosphate Li8NaV3(P2O7)3(PO4)2 were comprehensively studied, and compared with its isologue Li9V3(P2O7)3(PO4)2. Both Li8NaV3(P2O7)3(PO4)2 and Li9V3(P2O7)3(PO4)2 were synthesized via an original two-step method for the first time. The sintering temperature of Li8NaV3(P2O7)3(PO4)2 (650 °C) was much lower than that of Li9V3(P2O7)3(PO4)2 (750 °C). The Rietveld structure refinement indicated that Na ions occupied the Li1(2b) site of Li9V3(P2O7)3(PO4)2 as expected, and Li8NaV3(P2O7)3(PO4)2 showed a single charge plateau at 4.4 V vs. Li in the 1st cycle. However, the Na ions migrated from Li1(2b) site after the initial cycle, and the charge plateau at 3.7 V vs. Li reappeared. On the other hand, both Li9V3(P2O7)3(PO4)2 and Li8NaV3(P2O7)3(PO4)2 can deliver a high reversible capacity (∼200 mAh g-1), and reveal excellent cycle and rate performance in 3.0-0.05 V vs. Li. The gentle structure changes along with abundant Li intercalation into the bulks suggested that Li9V3(P2O7)3(PO4)2 and Li8NaV3(P2O7)3(PO4)2 were also promising anode materials for Li-ion batteries.

  15. 137Cs and 210Po in Pacific Walrus and Bearded Seal from St. Lawrence Island, Alaska

    SciTech Connect

    Hamilton, T F; Seagars, D J; Jokela, T; Layton, D

    2005-02-02

    The activity concentration of Cesium-137 ({sup 137}Cs) and naturally-occurring Polonium-210 ({sup 210}Po) were measured in the muscle tissue, kidney and liver of Pacific walrus (Odobenus rosmarus divergens) and bearded seal (Erignathus barbatus) collected by native hunters from the Bering Sea. The mean {sup 137}Cs concentrations in muscle, liver and kidney of Pacific walrus were 0.07, 0.09 and 0.07 Bq kg{sup -1} (N= 5, wet weight), respectively, and 0.17, 0.10, and 0.17 Bq kg{sup -1} (N=2, wet weight), respectively, in bearded seal. In general, {sup 137}Cs tissue concentrations are significantly lower than those previously reported for mammals from other regions. By comparison, {sup 210}Po activity concentrations appear to be higher than those reported elsewhere but a larger variation. The mean {sup 210}Po concentration in the muscle tissue, liver and kidney of Pacific walrus (N=5, wet weight) were 28.7, 189, and 174 Bq kg{sup -1}, respectively. This compares with {sup 210}Po concentration values (N=2, wet weight) of 27, 207, and 68 Bq kg{sup -1} measured in the muscle tissue, liver and kidney, of bearded seal, respectively. Estimated bioaccumulation factors--as defined by the radionuclide concentration ratio between the target tissue to that in sea water--were two to three orders of magnitude higher for {sup 210}Po that those of {sup 137}Cs. We conclude from radiological dose estimates that ingestion of {sup 137}Cs in foods derived from walrus and seal will pose no threat to human health. This work has important implications for assessing health risks to Alaskan coastal communities concerned about the dumping of nuclear waste in the Russia Arctic.

  16. Structural and spectroscopic properties of pure and doped LiCe(PO{sub 3}){sub 4}

    SciTech Connect

    Abdelhedi, M.; Horchani-Naifer, K.; Dammak, M.; Ferid, M.

    2015-10-15

    Graphical abstract: Emission and excitation and spectra of Eu{sup 3+} doped LiCe(PO{sub 3}){sub 4} host lattice with 1, 2, 3 and 4 mol%. - Highlights: • Europium–doped LiCe(PO{sub 3}){sub 4} were prepared by flux method. • It was analyzed by infrared and Raman spectroscopy, and luminescence spectroscopy. • LiCe(PO{sub 3}){sub 4} doped with Eu{sup 3+} ions as luminophore host materials to produce an intense red. - Abstract: Single crystals of LiCe(PO{sub 3}){sub 4} polyphosphate have been synthesized by the flux method and its structural and luminescence properties have been investigated. This compound crystallizes in the space group C2/c with unit cell dimensions a = 16.52(7) Å, b = 7.09(4) Å, c = 9.83 (4)Å, β = 126.29(4)°, Z = 8 and V = 927.84(3) Å{sup 3}. The obtained polytetraphosphate exhibits very small crystals and the dopant Eu{sup 3+} ions were successfully incorporated into the sites of Ce{sup 3+} ions of the host lattice. The spectroscopy properties confirm the potentiality of present LiCe(PO{sub 3}){sub 4} doped with Eu{sup 3+} ions as luminophore host materials to produce an intense red luminescence at 628 nm corresponding to {sup 5}D{sub 0} → {sup 7}F{sub 2} emission level and have significant importance in the development of emission optical systems.

  17. 137Cs and 210Po in Pacific walrus and bearded seal from St. Lawrence Island, Alaska.

    PubMed

    Hamilton, Terry; Seagars, Dana; Jokela, Terry; Layton, David

    2008-06-01

    The activity concentration of Cesium-137 ((137)Cs) and naturally-occurring Polonium-210 ((210)Po) were measured in the muscle tissue, kidney and liver of Pacific walrus (Odobenus rosmarus divergens) and bearded seal (Erignathus barbatus) collected by native hunters from the Bering Sea during May 1996. The mean (137)Cs concentrations in muscle, liver and kidney of Pacific walrus were 0.07, 0.09 and 0.07 Bq kg(-1) (n=5, wet weight), respectively, and 0.17, 0.10, and 0.17 Bq kg(-1) (n=2, wet weight), respectively, in bearded seal. In general, (137)Cs tissue concentrations are significantly lower than those previously reported for mammals from other regions. By comparison, (210)Po activity concentrations are more variable and appear to be higher level compared with mammal data from other regions. The mean (210)Po concentration in the muscle tissue, liver and kidney of Pacific walrus (n=5, wet weight) were 28.7, 189, and 174 Bq kg(-1), respectively. This compares with (210)Po concentration values (n=2, wet weight) of 27, 207 and 68 Bq kg(-1) measured in the muscle tissue, liver and kidney, of bearded seal, respectively. Estimated concentration factors--as defined by the radionuclide concentration ratio between the target tissue to that in sea water--were two to three orders of magnitude higher for (210)Po that those of (137)Cs. We conclude from radiological dose estimates that ingestion of (137)Cs in foods derived from walrus and seal will pose no threat to human health. This work has important implications for assessment of risks of Alaskan coastal communities concerned about the dumping of nuclear waste in the Russia Arctic.

  18. Unveil the Chemistry of Olivine FePO4 as Magnesium Battery Cathode.

    PubMed

    Zhang, Ruigang; Ling, Chen

    2016-07-20

    Despite growing interest in magnesium batteries, it is still a challenge to find a cathode that fulfills requirements such as high capacity and good cyclability. Because of their positions in the periodic table and the similar ionic sizes of lithium and magnesium, it was naturally postulated that a classical intercalation-type Li-ion battery cathode may also accommodate the intercalation of Mg. On the contrary, many Li-ion battery cathodes performed very poorly in Mg cells, although the mechanism behind such phenomena is still unclear. Here we provide first-hand evidence about the chemistry of olivine FePO4 as Mg battery cathode using a combined theoretical and experimental approach. Although LiFePO4 is a commercial cathode with extraordinary good performance in Li-ion batteries, the measured capacity of FePO4 in nonaqueous Mg cell was only ∼13 mAh/g. Density functional theory calculations predicted sufficient mobility of Mg(2+) in FePO4 lattice to support the insertion of Mg at a reasonable rate, suggesting the poor performance cannot be simply attributed to the limitation of Mg(2+) diffusion. Instead, the recorded low capacity was the result of surface amorphorization that prohibited the electrochemical reaction from penetrating deeply into the bulk phase. The amorphorization had a thermodynamic origin from the instability of intercalated product, which was predicted from DFT calculations and supported by the failure to synthesize magnesiated FePO4 in the solid state reaction route. These results highlighted the importance of a thermodynamically preferred intercalation in order to achieve successful Mg battery cathode.

  19. Amorphous AlPO sub 4 as catalyst support: 2. Characterization of amorphous aluminum phosphates

    SciTech Connect

    Rebenstorf, B.; Lindblad, T.; Andersson, S.L.T. )

    1991-04-01

    Three different amorphous aluminum phosphates have been characterized by their specific surface area and pore volume and by XPS and FTIR studies. Three types of Al surface hydroxyl groups at 3793.8, 3768.5, and 3743.2 cm{sup {minus}1} and only one type of P surface hydroxyl groups at 3677.5 cm{sup {minus}1} are found in FTIR spectra after evacuation at 800{degree}C. The ratio of the integrated absorbance of the IR bands from AlOH and POH surface groups is a sensitive tool to study the surface of AlPO{sub 4} directly. A linear relation between the electronegativity of the metal ion and the stretching vibration of surface hydroxyl groups is proposed for Al, Si, P, and B tetrahedral surface ions. The three Al surface hydroxyl groups are assigned to four-coordinated (tetrahedral), five-coordinated, and six-coordinated surface Al ions. Amorphous AlPO{sub 4} contains four- and five-coordinated Al ions and AlPO{sub 4} with high specific surface area also has six-coordinated Al ions at the surface. CO is adsorbed on the phosphorus surface hydroxyl groups at low temperature, giving an IR band at 2170 cm{sup {minus}1}, while the IR band from the PO-H group is shifted to 3495 cm{sup {minus}1}. On AlPO{sub 4} of high surface area, CO is also adsorbed on coordinatively unsaturated, five-coordinated Al surface ions. Four-coordinated Al ions are also found, but none with the coordination number three. Impregnation with chromium compounds in ethanol does not change the specific surface area, whereas impregnation in water resulted in a decreased specific surface area, to less than half of its previous value.

  20. Unveil the Chemistry of Olivine FePO4 as Magnesium Battery Cathode.

    PubMed

    Zhang, Ruigang; Ling, Chen

    2016-07-20

    Despite growing interest in magnesium batteries, it is still a challenge to find a cathode that fulfills requirements such as high capacity and good cyclability. Because of their positions in the periodic table and the similar ionic sizes of lithium and magnesium, it was naturally postulated that a classical intercalation-type Li-ion battery cathode may also accommodate the intercalation of Mg. On the contrary, many Li-ion battery cathodes performed very poorly in Mg cells, although the mechanism behind such phenomena is still unclear. Here we provide first-hand evidence about the chemistry of olivine FePO4 as Mg battery cathode using a combined theoretical and experimental approach. Although LiFePO4 is a commercial cathode with extraordinary good performance in Li-ion batteries, the measured capacity of FePO4 in nonaqueous Mg cell was only ∼13 mAh/g. Density functional theory calculations predicted sufficient mobility of Mg(2+) in FePO4 lattice to support the insertion of Mg at a reasonable rate, suggesting the poor performance cannot be simply attributed to the limitation of Mg(2+) diffusion. Instead, the recorded low capacity was the result of surface amorphorization that prohibited the electrochemical reaction from penetrating deeply into the bulk phase. The amorphorization had a thermodynamic origin from the instability of intercalated product, which was predicted from DFT calculations and supported by the failure to synthesize magnesiated FePO4 in the solid state reaction route. These results highlighted the importance of a thermodynamically preferred intercalation in order to achieve successful Mg battery cathode. PMID:27355741

  1. Magnetic Transitions in the Spin-5/2 Frustrated Magnet BiMn2PO6 and Strong Lattice Softening in BiMn2PO6 and BiZn2PO6 Below 200 K

    SciTech Connect

    Nath, R; Ranjith, K M; Roy, B; Johnston, D C; Furukawa, Y; Tsirlin, A A

    2014-07-01

    The crystallographic, magnetic, and thermal properties of polycrystalline BiMn2PO6 and its nonmagnetic analog BiZn2PO6 are investigated by x-ray diffraction, magnetization M, magnetic susceptibility χ, heat capacity Cp, and P31 nuclear magnetic resonance (NMR) measurements versus applied magnetic field H and temperature T as well as by density-functional band theory and molecular-field calculations. Both compounds show a strong monotonic lattice softening on cooling, where the Debye temperature decreases by a factor of two from ΘD~650 K at T=300 K to ΘD~300 K at T=2 K. The χ(T) data for BiMn2PO6 above 150 K follow a Curie-Weiss law with a Curie constant consistent with a Mn+2 spin S=5/2 with g factor g=2 and an antiferromagnetic (AFM) Weiss temperature θCW≃-78 K. The χ data indicate long-range AFM ordering below TN≃30 K, confirmed by a sharp λ-shaped peak in Cp(T) at 28.8 K. The magnetic entropy at 100 K extracted from the Cp(T) data is consistent with spin S=5/2 for the Mn+2 cations. The band-theory calculations indicate that BiMn2PO6 is an AFM compound with dominant interactions J1/kB≃6.7 K and J3/kB≃5.6 K along the legs and rungs of a Mn two-leg spin-ladder, respectively. However, sizable and partially frustrating interladder couplings lead to an anisotropic three-dimensional magnetic behavior with long-range AFM ordering at TN≃30 K observed in the χ, Cp, and NMR measurements. A second magnetic transition at ≈10 K is observed from the χ and NMR measurements but is not evident in the Cp data. The Cp data at low T suggest a significant contribution from AFM spin waves moving in three dimensions and the absence of a spin-wave gap. A detailed analysis of the NMR spectra indicates commensurate magnetic order between 10 and 30 K, while below 10 K additional features appear that may arise from an incommensurate modulation and/or spin canting. The commensurate order is consistent with microscopic density functional calculations that yield a

  2. Synthesis, structure and NMR characterization of a new monomeric aluminophosphate [ dl-Co(en) 3] 2[Al(HPO 4) 2(H 1.5PO 4) 2(H 2PO 4) 2](H 3PO 4) 4 containing four different types of monophosphates

    NASA Astrophysics Data System (ADS)

    Chen, Peng; Li, Jiyang; Xu, Jun; Duan, Fangzheng; Deng, Feng; Xu, Ruren

    2009-03-01

    A new zero-dimensional (0D) aluminophosphate monomer [ dl-Co(en) 3] 2[Al(HPO 4) 2(H 1.5PO 4) 2(H 2PO 4) 2](H 3PO 4) 4 (designated AlPO-CJ38) with Al/P ratio of 1/6 has been solvothermally prepared by using racemic cobalt complex dl-Co(en) 3Cl 3 as the template. The Al atom is octahedrally linked to six P atoms via bridging oxygen atoms, forming a unique [Al(HPO 4) 2(H 1.5PO 4) 2(H 2PO 4) 2] 6- monomer. Notably, there exists intramolecular symmetrical O⋯H⋯O bonds, which results in pseudo-4-rings stabilized by the strong H-bonding interactions. The structure is also featured by the existence of four different types of monophosphates that have been confirmed by 31P NMR and 1H NMR spectra. The crystal data are as follows: AlPO-CJ38, [ dl-Co(en) 3] 2[Al(HPO 4) 2(H 1.5PO 4) 2(H 2PO 4) 2](H 3PO 4) 4, M = 1476.33, monoclinic, C2/ c (No. 15), a = 36.028(7) Å, b = 8.9877(18) Å, c = 16.006(3) Å, β = 100.68(3)°, U = 5093.2(18) Å 3,Z = 4, R1 = 0.0509 ( I > 2 σ( I)) and wR2 = 0.1074 (all data). CCDC number 689491.

  3. Engaging Scientists in Meaningful E/PO: How the NASA SMD E/PO Community Addresses the Needs of the Higher Ed Community

    NASA Astrophysics Data System (ADS)

    Manning, James; Meinke, Bonnie K.; Schultz, Gregory R.; Smith, Denise A.; Lawton, Brandon L.; Gurton, Suzanne; NASA Astrophysics E/PO Community

    2015-01-01

    The NASA Astrophysics Science Education and Public Outreach Forum (SEPOF) coordinates the work of NASA Science Mission Directorate (SMD) Astrophysics EPO projects and their teams to bring cutting-edge discoveries of NASA missions to the introductory astronomy college classroom. The Astrophysics Forum assists scientist and educator involvement in SMD E/PO (uniquely poised to foster collaboration between scientists with content expertise and educators with pedagogy expertise) and makes SMD E/PO resources and expertise accessible to the science and education communities. We present three new opportunities for college instructors to bring the latest NASA discoveries in Astrophysics into their classrooms.To address the expressed needs of the higher education community, the Astrophysics Forum collaborated with the Astrophysics E/PO community, researchers, and Astronomy 101 instructors to place individual science discoveries and learning resources into context for higher education audiences. Among these resources are two Resource Guides on the topics of cosmology and exoplanets, each including a variety of accessible sources.The Astrophysics Forum also coordinates the development of the Astro 101 slide set series--5 to 7-slide presentations on new discoveries from NASA Astrophysics missions relevant to topics in introductory astronomy courses. These sets enable Astronomy 101 instructors to include new discoveries not yet in their textbooks into the broader context of the course: http://www.astrosociety.org/education/astronomy-resource-guides/.The Astrophysics Forum also coordinated the development of 12 monthly Universe Discovery Guides, each featuring a theme and a representative object well-placed for viewing, with an accompanying interpretive story, strategies for conveying the topics, and supporting NASA-approved education activities and background information from a spectrum of NASA missions and programs: http://nightsky.jpl.nasa.gov/news-display.cfm?News_ID=611

  4. Synthesis, structure and magnetic properties of new phosphates K 2Mn 0.5Ti 1.5(PO 4) 3 and K 2Co 0.5Ti 1.5(PO 4) 3 with the langbeinite structure

    NASA Astrophysics Data System (ADS)

    Ogorodnyk, Ivan V.; Zatovsky, Igor V.; Slobodyanik, Nikolay S.; Baumer, Vyacheslav N.; Shishkin, Oleg V.

    2006-11-01

    New complex phosphates of the general formula K 2M0.5Ti 1.5(PO 4) 3 ( M=Mn, Co) have been obtained from the melting mixture of KPO 3, K 4P 2O 7, TiO 2 and CoCO 3· mCo(OH) 2 or Mn(H 2PO 4) 2 by means of a flux technique. The synthesized phosphates have been characterized by the single-crystal X-ray diffraction and the FTIR-spectroscopy. The compounds crystallize in the cubic system with the space group P2 13 and cell parameters a=9.9030(14) Å for K 2Mn 0.5Ti 1.5(PO 4) 3 and a=9.8445(12) Å for K 2Co 0.5Ti 1.5(PO 4) 3. Both phosphates are isostructural with the langbeinite mineral and contain four formula unit K 2M0.5Ti 1.5(PO 4) 3 per unit cell. The structure can be described using [ M2(PO 4) 3] framework composed of two [ MO 6] octahedra interlinked via three [PO 4] tetrahedra. The Curie-Weiss-type behavior is observed in the magnetic susceptibility.

  5. Phase equilibrium relations in the binary systems LiPO 3CeP 3O 9 and NaPO 3CeP 3O 9

    NASA Astrophysics Data System (ADS)

    Rzaigui, Mohamed; Ariguib, Najia Kbir

    1981-10-01

    The LiPO 3CeP 3O 9 and NaPO 3CeP 3O 9 systems have been investigated for the first time by DTA, X-ray diffraction, and infrared spectroscopy. Each system forms a single 1:1 compound. LiCe(PO 3) 4 melts in a peritectic reaction at 980°C. NaCe(PO 3) 4 melts incongruently, too, at 865°C. These compounds have a monoclinic unit cell with the parameters: a = 16.415(6), b = 7,042(6), c = 9.772(7)Å; β = 126.03(5)°; Z = 4; space group {C 2}/{c} for LiCe (PO 3) 4; and a = 9.981(4), b = 13.129(6), c = 7.226(5) Å, β = 89.93(4)°, Z = 4, space group {P2 1}/{n} for NaCe(PO 3) 4. It is established that both compounds are mixed polyphosphates with chain structure of the type | MIIMIIIII (PO 3) 4| ∞MII: alkali metal, MIIIII: rare earth.

  6. Caspase-1-like regulation of the proPO-system and role of ppA and caspase-1-like cleaved peptides from proPO in innate immunity.

    PubMed

    Jearaphunt, Miti; Noonin, Chadanat; Jiravanichpaisal, Pikul; Nakamura, Seiko; Tassanakajon, Anchalee; Söderhäll, Irene; Söderhäll, Kenneth

    2014-04-01

    Invertebrates rely on innate immunity to respond to the entry of foreign microorganisms. One of the important innate immune responses in arthropods is the activation of prophenoloxidase (proPO) by a proteolytic cascade finalized by the proPO-activating enzyme (ppA), which leads to melanization and the elimination of pathogens. Proteolytic cascades play a crucial role in innate immune reactions because they can be triggered more quickly than immune responses that require altered gene expression. Caspases are intracellular proteases involved in tightly regulated limited proteolysis of downstream processes and are also involved in inflammatory responses to infections for example by activation of interleukin 1ß. Here we show for the first time a link between caspase cleavage of proPO and release of this protein and the biological function of these fragments in response to bacterial infection in crayfish. Different fragments from the cleavage of proPO were studied to determine their roles in bacterial clearance and antimicrobial activity. These fragments include proPO-ppA, the N-terminal part of proPO cleaved by ppA, and proPO-casp1 and proPO-casp2, the fragments from the N-terminus after cleavage by caspase-1. The recombinant proteins corresponding to all three of these peptide fragments exhibited bacterial clearance activity in vivo, and proPO-ppA had antimicrobial activity, as evidenced by a drastic decrease in the number of Escherichia coli in vitro. The bacteria incubated with the proPO-ppA fragment were agglutinated and their cell morphology was altered. Our findings show an evolutionary conserved role for caspase cleavage in inflammation, and for the first time show a link between caspase induced inflammation and melanization. Further we give a more detailed understanding of how the proPO system is regulated in time and place and a role for the peptide generated by activation of proPO as well as for the peptides resulting from Caspase 1 proteolysis.

  7. Crystal structures of lazulite-type oxidephosphates Ti IIITi IV3O 3(PO 4) 3 and MIII4Ti IV27O 24(PO 4) 24 ( MIII=Ti, Cr, Fe)

    NASA Astrophysics Data System (ADS)

    Schöneborn, M.; Glaum, R.; Reinauer, F.

    2008-06-01

    Single crystals of the oxidephosphates Ti IIITi IV3O 3(PO 4) 3 (black), Cr III4Ti IV27O 24(PO 4) 24 (red-brown, transparent), and Fe III4Ti IV27O 24(PO 4) 24 (brown) with edge-lengths up to 0.3 mm were grown by chemical vapour transport. The crystal structures of these orthorhombic members (space group F2 dd ) of the lazulite/lipscombite structure family were refined from single-crystal data [Ti IIITi IV3O 3(PO 4) 3: Z=24, a=7.3261(9) Å, b=22.166(5) Å, c=39.239(8) Å, R1=0.029, w R2=0.084, 6055 independent reflections, 301 variables; Cr III4Ti IV27O 24(PO 4) 24: Z=1, a=7.419(3) Å, b=21.640(5) Å, c=13.057(4) Å, R1=0.037, w R2=0.097, 1524 independent reflections, 111 variables; Fe III4Ti IV27O 24(PO 4) 24: Z=1, a=7.4001(9) Å, b=21.7503(2) Å, c=12.775(3) Å, R1=0.049, w R2=0.140, 1240 independent reflections, 112 variables). For Ti IIITi IVO 3(PO 4) 3 a well-ordered structure built from dimers [Ti III,IV2O 9] and [Ti IV,IV2O 9] and phosphate tetrahedra is found. The metal sites in the crystal structures of Cr 4Ti 27O 24(PO 4) 24 and Fe 4Ti 27O 24(PO 4) 24, consisting of dimers [ MIIITi IVO 9] and [Ti IV,IV2O 9], monomeric [Ti IVO 6] octahedra, and phosphate tetrahedra, are heavily disordered. Site disorder, leading to partial occupancy of all octahedral voids of the parent lipscombite/lazulite structure, as well as splitting of the metal positions is observed. According to Guinier photographs Ti III4Ti IV27O 24(PO 4) 24 ( a=7.418(2) Å, b=21.933(6) Å, c=12.948(7) Å) is isotypic to the oxidephosphates MIII4Ti IV27O 24(PO 4) 24 ( MIII: Cr, Fe). The UV/vis spectrum of Cr 4Ti 27O 24(PO 4) 24 reveals a rather small ligand-field splitting Δ o=14,370 cm -1 and a very low nephelauxetic ratio β=0.72 for the chromophores [Cr IIIO 6] within the dimers [Cr IIITi IVO 9].

  8. Excess of polonium-210 activity in the surface urban atmosphere. Part 2: origin of ²¹⁰Po excess.

    PubMed

    Długosz-Lisiecka, Magdalena

    2015-02-01

    The presence of significant (210)Po activity, unsupported by its grandparent radionuclide (210)Pb, in the surface atmosphere of industrialized regions can originate from human technical activities. In urban air, the activity ratio of (210)Po to (210)Pb might increase as a result of natural condensation and coagulation processes of relatively volatile (210)Po-containing species emitted during coal combustion processes. The presence of excess of (210)Po cannot be explained by its in-growth from radioactive decay of (210)Bi. About 50% of (210)Po radionuclide released during coal combustion processes can be emitted into air as gaseous or ultrafine products. Subsequently, these products are quickly attached to the surface of fine particles suspended in the air. As a result, an excess of (210)Po activity in aerosols has been reported. However, in this manner, As much as 11 GBq of (210)Po per year can enter the urban air from the local coal power plants in Lodz city, Poland.

  9. Baseline concentration of ²¹⁰Po and ²¹⁰Pb in Sargassum from the northern Gulf.

    PubMed

    Uddin, S; Aba, A; Bebhehani, M

    2015-01-15

    This baseline study highlights the (210)Po and (210)Pb concentration in two species of the benthic macroalgae Sargassum from northern Gulf, also known as the ROPME Sea Area (RSA). Within the marine environment, (210)Po is initially absorbed from water and concentrated by phytoplankton and macroalgae, and this concentrated (210)Po can then readily be passed along to the higher trophic level of the marine food web. The (210)Po concentration measured in Sargassum boveanum (22.5-25.6 Bq kg(-1)) was higher than that in Sargassum oligocystum (20.2-22.5 Bq kg(-1)), but is not statistically significant (p>0.064), where as the difference between (210)Pb concentrations in Sargassum boveanum (15.3-16.8 Bq kg(-1)) and Sargassum oligocystum (18.4-22.0 Bq kg(-1)) was statistically significant (p>0.019). The measured concentration factor for (210)Po in Sargassum in the northern Gulf varied between 0.55 and 1.2×10(4), values higher to the IAEA recommended value of 1×10(3). The (210)Po enrichment is observed in both the species of Sargassum,(210)Po/(210)Pb ratio was >1 at all the stations for all the samples.

  10. DL-/PO-phosphatidylcholine restores restraint stress-induced depression-related behaviors and spatial memory impairment.

    PubMed

    Kanno, Takeshi; Jin, Yu; Nishizaki, Tomoyuki

    2014-09-01

    The present study investigated the effects of 1,2-dilinoleoyl-sn-glycero-3-phosphocholine (DL-PC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (PO-PC) on depression-related behaviors and spatial memory impairment in mice subjected to restraint stress. The immobility time in forced-swim and tail-suspension tests for mice subjected to restraint stress was significantly longer than that for nonstressed control mice, and oral coadministration of DL-PC and PO-PC (DL-/PO-PC; DL-PC : PO-PC=1 : 1) shortened the prolonged immobility time in a dose (0.1-5 mg/kg)-dependent manner. In the water maze test, the retention latency for stressed mice was significantly longer than that for control mice and DL-/PO-PC (1 mg/kg, per os) reversed the prolonged latency to control levels. Phosphorylation of Akt and glycogen synthase kinase 3β (GSK-3β) in the hypothalamus of stressed mice was significantly reduced compared with that for control mice, and DL-/PO-PC (1 mg/kg, per os) recovered the reduced phosphorylation of Akt and GSK-3β. The results of the present study indicate that DL-/PO-PC has the potential to ameliorate stress-induced depression-related behaviors and memory impairment, possibly by activating Akt and inhibiting GSK-3β.

  11. Estimation of 210Po and its risk to human beings due to consumption of marine species at Mumbai, India.

    PubMed

    Mishra, S; Bhalke, S; Pandit, G G; Puranik, V D

    2009-07-01

    (210)Po was estimated in the edible muscle and soft tissue of 15 different marine species (fish, crab, prawn and bivalve) collected from Trans-Thane Creek area (Trombay) and Thane. Potential risks associated with consumption of marine organisms due to (210)Po collected from this particular area to human beings were assessed. Estimation of (210)Po was carried out using radiochemical separation and alpha spectrometric technique. The concentration of (210)Po was found to vary from 0.18 to 10.9 Bqkg(-1) wet wt in different biota species and maximum concentrations were observed in bivalves. The variations in (210)Po concentration in different species are mainly due to difference in metabolism and feeding habits. The daily intake and individual dose of (210)Po to human beings through biota consumption was calculated and found to be 31.89 mBqd(-1) and 19.44 microSvyr(-1), respectively. An assessment of the risk on human beings due to consumption of marine organism was undertaken using carcinogenic slope factor for (210)Po. 5th, 50th and 95th percentile of life time risk was calculated to be 9.74E-06, 4.39E-05 and 2.12E-04, respectively.

  12. Thermal Expansion of NaZr2(PO4)3 Family Ceramics in a Low-Temperature Range

    NASA Astrophysics Data System (ADS)

    Miyazaki, Hidetoshi; Ushiroda, Isao; Itomura, Daisuke; Hirashita, Tsunehisa; Adachi, Nobuyasu; Ota, Toshitaka

    2008-09-01

    NZP family ceramics - NaZr2(PO4)3 (NZP), KZr2(PO4)3, RbZr2(PO4)3, Cs Zr2(PO4)3, CaZr4(PO4)6, SrZr4(PO4)6 (SrZP), and BaZr4(PO4)6 - were synthesized by a solid-state reaction, and their thermal expansion properties were investigated by X-ray diffraction measurement in a temperature range of -150 to 250 °C. The increases in the average thermal expansion coefficients of all the NZP family ceramics in this low temperature range (-150 to 250 °C) were smaller than those in a high temperature range (room temperature to 1000 °C). The thermal expansion coefficient of the SrZP ceramic was 0.2×10-6/°C between -150 to 250 °C, which is very small. This proved that SrZP has a near-zero thermal expansion coefficient in a low-temperature range.

  13. Excess of polonium-210 activity in the surface urban atmosphere. Part 2: origin of ²¹⁰Po excess.

    PubMed

    Długosz-Lisiecka, Magdalena

    2015-02-01

    The presence of significant (210)Po activity, unsupported by its grandparent radionuclide (210)Pb, in the surface atmosphere of industrialized regions can originate from human technical activities. In urban air, the activity ratio of (210)Po to (210)Pb might increase as a result of natural condensation and coagulation processes of relatively volatile (210)Po-containing species emitted during coal combustion processes. The presence of excess of (210)Po cannot be explained by its in-growth from radioactive decay of (210)Bi. About 50% of (210)Po radionuclide released during coal combustion processes can be emitted into air as gaseous or ultrafine products. Subsequently, these products are quickly attached to the surface of fine particles suspended in the air. As a result, an excess of (210)Po activity in aerosols has been reported. However, in this manner, As much as 11 GBq of (210)Po per year can enter the urban air from the local coal power plants in Lodz city, Poland. PMID:25567664

  14. Baseline concentration of ²¹⁰Po and ²¹⁰Pb in Sargassum from the northern Gulf.

    PubMed

    Uddin, S; Aba, A; Bebhehani, M

    2015-01-15

    This baseline study highlights the (210)Po and (210)Pb concentration in two species of the benthic macroalgae Sargassum from northern Gulf, also known as the ROPME Sea Area (RSA). Within the marine environment, (210)Po is initially absorbed from water and concentrated by phytoplankton and macroalgae, and this concentrated (210)Po can then readily be passed along to the higher trophic level of the marine food web. The (210)Po concentration measured in Sargassum boveanum (22.5-25.6 Bq kg(-1)) was higher than that in Sargassum oligocystum (20.2-22.5 Bq kg(-1)), but is not statistically significant (p>0.064), where as the difference between (210)Pb concentrations in Sargassum boveanum (15.3-16.8 Bq kg(-1)) and Sargassum oligocystum (18.4-22.0 Bq kg(-1)) was statistically significant (p>0.019). The measured concentration factor for (210)Po in Sargassum in the northern Gulf varied between 0.55 and 1.2×10(4), values higher to the IAEA recommended value of 1×10(3). The (210)Po enrichment is observed in both the species of Sargassum,(210)Po/(210)Pb ratio was >1 at all the stations for all the samples. PMID:25440188

  15. Preparation of LiCoPO 4/C nanocomposite cathode of lithium batteries with high rate performance

    NASA Astrophysics Data System (ADS)

    Doan, The Nam Long; Taniguchi, Izumi

    LiCoPO 4/C nanocomposites could be successfully prepared by a combination of spray pyrolysis and wet ball-milling followed by heat treatment. X-ray diffraction analysis confirmed that the LiCoPO 4/C nanocomposites were well crystallized in an orthorhombic structure with Pmna space group. Scanning electron microscopy and transmission electron microscopy with equipped energy dispersive spectroscopy verified that the LiCoPO 4/C nanocomposites were the agglomerates of LiCoPO 4 primary particles with a geometric mean diameter of 87 nm, and the carbon was well distributed on the surface of the agglomerates. The LiCoPO 4/C nanocomposites were used as cathode active materials for lithium batteries, and the electrochemical tests were carried out for the cell Li|1 M LiPF 6 in EC:DMC = 1:1|LiCoPO 4/C at various charge-discharge rates. The cells delivered first discharge capacities of 142 and 109 mAh g -1 at 0.05 and 20 C, respectively. Furthermore, the discharge capacity after 40 cycles corresponded to 87% of initial one at 0.1 C rate. The excellent rate capability of the cells is mainly due to the well distributed carbon on the LiCoPO 4 agglomerates, and a much smaller lithium ion diffusion distance in the electrode.

  16. Microbundles of carbon nanostructures as binder free highly conductive matrix for LiFePO4 battery cathode

    NASA Astrophysics Data System (ADS)

    Lalia, Boor Singh; Shah, Tushar; Hashaikeh, Raed

    2015-03-01

    Microbundles of carbon nanostructures (CNS) have been used to fabricate binder-free LiFePO4 electrodes. The inherent ability of CNS to form a nano-porous structure after the reassembly of CNS dispersion from solution to film-forming state is used to encapsulate the LiFePO4 particles. The LiFePO4/CNS electrode shows high electrical conductivity of 9.1 S cm-1 compared to 0.4 S cm -1 for conventional LiFePO4/carbon electrodes. LiFePO4/CNS flexible electrodes shows specific discharge capacity of 56 mAh g-1, 41 mAh g-1 and 37 mAh g-1 at 1C, 3C and 5C rates respectively. These specific discharge capacities are higher than that of conventional LiFePO4/carbon electrodes i.e. 40 mAh g-1, 13 mAh g-1 and 0.01 mAh g-1 at 1C, 3C and 5C rates respectively. Improvements in the specific discharge capacity at high C-rate is attributed to highly conductive pathways between the CNS and LiFePO4 particles, which assist fast transport of electrons at the electrode/CNS interfaces and between the electrode particles for rapid electrochemical reactions.

  17. High-performance, nanostructure LiMnPO4/C composites synthesized via one-step solid state reaction

    NASA Astrophysics Data System (ADS)

    Zheng, Jugong; Ni, Liang; Lu, Yanwen; Qin, Cancan; Liu, Panxing; Wu, Tongfu; Tang, Yuefeng; Chen, Yanfeng

    2015-05-01

    LiMnPO4 is proposed as more promising cathode material as LiFePO4, while poor electronic conductivity and Jahn-Teller effects during charge/discharge processes hinder the electrochemical performance. To overcome these problems, one-step solid state reaction method is developed to synthesize LiMnPO4/C composites, which is with nanostructure, high crystallinity and good carbon coating. Manganese oxide sources and calcination temperature are investigated as factors for preparing high-performance LiMnPO4/C for Li-ion batteries. The results show that the LiMnPO4/C composites prepared with mixed manganese oxide deliver a superior initial capacity of 153 mAh g-1 at 0.05 C and high rate performance with discharge capacities of 123 mAh g-1 at 1 C and 103 mAh g-1 at 2 C. And the LiMnPO4/C composites synthesized at 600 °C can retain 94% of the initial capacity after 200 cycles at 1 C, revealing a stable cycling stability. Therefore, one-step solid state reaction brings to light the synthesis of high performance LiMnPO4/C cathode materials and is suitable for large scale production.

  18. sup 210 Po and sup 210 Pb remobilization from lake sediments in relation to iron and manganese cycling

    SciTech Connect

    Benoit, G.; Hemond, H.F. )

    1990-08-01

    The behavior of {sup 210}Po and {sup 210}Pb was studied in the water column of an oligotrophic, dimictic lake. Direct uptake of the radionuclides by sediments was negligible compared to removal on particles, and {sup 210}Pb scavenging was 4 times that of {sup 210}Po. Both nuclides were found to be significantly remobilized from sediments into the stratified, anoxic water column. Releases seem to be linked to the cycling of the transition metals, iron and possibly manganese. The distribution of both iron and {sup 210}Pb in stratified, anoxic waters can be modeled as constant release and rapid horizontal mixing/dilution; vertical turbulent transport had a negligible effect on element distributions. Upon contact with oxygen, iron rapidly reprecipitates, forming a particulate maximum and rescavenging {sup 210}Pb. Unlike {sup 210}Pb, much {sup 210}Po is released from sediments before overlying water becomes completely anoxic, leading to unsupported {sup 210}Po. {sup 210}Po cycling in the stratified water column is more complex than that of {sup 210}Pb, and additional removal mechanism(s) may be active, including perhaps oxidation of soluble Po(II) to insoluble Po(IV).

  19. Using the nutrient ratio NO/PO as a tracer of continental shelf waters in the central Arctic Ocean

    SciTech Connect

    Wilson, C.; Wallace, D.W.R. )

    1990-12-15

    Historical nitrate, phosphate, and dissolved oxygen data from the central Arctic Ocean are examined with particular emphasis on the conservative parameters NO (9 * NO{sub 3} + O{sub 2}) and PO (135 * PO{sub 4} + O{sub 2}). The NO/PO ratio is shown to increase with depth in the Canada Basin, being {approximately}0.78 in Surface and Upper Halocline Waters and {approximately}1.0 in the Atlantic Layer and Deep Waters. Lower Halocline Water is marked by NO and PO minima and intermediate NO/PO. NO/PO ratios from the Arctic shelf seas are examined to determine possible source regions for the various water masses. The NO/PO ration of Canada Basin Deep Water implies an upper bound of {approximately}11% shelf water contribution to this water mass. A slight oxygen maximum core in the Lower Halocline Water is identified at a salinity of S{double bond}34.5 in the vicinity of the Alpha Ridge. This core appears to be diminished by diapycnal mixing and does not extend into the Beaufort Gyre.

  20. Mapping the Naked Neck (NA) and Polydactyly (PO) mutants of the chicken with microsatellite molecular markers

    PubMed Central

    Pitel, Frédérique; Bergé, Régis; Coquerelle, Gérard; Crooijmans, Richard PMA; Groenen, Martien AM; Vignal, Alain; Tixier-Boichard, Michèle

    2000-01-01

    The bulked segregant analysis methodology has been used to map, with microsatellite markers, two morphological mutations in the chicken: polydactyly (PO) and naked neck (NA). These autosomal mutations show partial dominance for NA, and dominance with incomplete penetrance for PO. They were mapped previously to different linkage groups of the classical map, PO to the linkage group IV and NA being linked to the erythrocyte antigen CPPP. An informative family of 70 offspring was produced by mating a sire, heterozygous for each of the mutations, to 7 dams homozygous recessive for each locus. Three DNA pools were prepared, pool PO included 20 chicks exhibiting at least one extra-toe, pool NA included 20 non-polydactyly chicks showing the typical phenotype associated with heterozygosity for the naked neck mutation, and pool NP included 20 chicks exhibiting neither of the mutant phenotypes. Typings were done on an ABI-373 automatic sequencer with 147 microsatellite markers covering most of the genome. An unbalanced distribution of sire marker alleles were detected between pool PO, and pools NA and NP, for two markers of chromosome 2p, MCW0082 and MCW0247. A linkage analysis taking into account the incomplete penetrance of polydactyly (80%) was performed with additional markers of this region and showed that the closest marker to the PO locus was MCW0071 (5 cM, lod score = 9). MCW0071 lies within the engrailed gene EN2 in the chicken. In the mouse, the homologous gene maps on chromosome 5, close to the hemimelic extra-toes mutation Hx. In the case of the NA locus, markers of chromosome 3 were selected because CPPP was mapped on this chromosome. Analysis of individual typings showed a linkage of 5.7 cM (lod score = 13) between the NA locus and ADL0237 in the distal region of chromosome 3q. These results contribute to connecting the former classical map to the molecular genetic map of the chicken, and open the way to the identification of the molecular nature of two

  1. Correlation between radiosensitivity, percentage hypoxic cells and pO2 measurements in one rodent and two human tumor xenografts.

    PubMed

    Thomas, C D; Chavaudra, N; Martin, L; Guichard, M

    1994-07-01

    Computerized pO2 histography has been used to measure the intratumor pO2 in patients for the past few years, and there is now evidence that these tumors contain hypoxic cells. One of the major questions that remains to be answered is the relevance of such data to radiosensitivity. The present study looks for a correlation between intratumor pO2, the percentage of hypoxic cells in the tumor and the radiosensitization induced by carbogen and/or the oxygen carrier, perflubron emulsion. Two human tumor xenografts (HRT18, Na11+) and one rodent tumor (EMT6) were used. The radiosensitivity (clonogenic assay) and the oxygen tension (computerized pO2 histography) were measured. All experiments were performed under similar conditions. Carbogen increased tumor radiosensitivity; sensitization was greatest when 4 ml/kg perflubron emulsion was used in conjunction with carbogen. The pO2 distribution was shifted to higher pO2 values in the tumors whatever the treatment; the shift was greater for perflubron emulsion plus carbogen. The low pO2 values (< 0.4 kPa) were lost for the HRT18 cells. A correlation (EMT6, HRT18) or a link (Na11+) between the radiosensitization and the oxygen tension measurements was found for values below 1.07 or 1.33 kPa. A trend between the percentage of hypoxic cells and pO2 measurements was found taking into account pO2 measurements comprised between 0.27 and 0.67 kPa. PMID:8016297

  2. Optimising a balloon-borne polarimeter in the hard X-ray domain: From the PoGOLite Pathfinder to PoGO+

    NASA Astrophysics Data System (ADS)

    Chauvin, M.; Jackson, M.; Kawano, T.; Kiss, M.; Kole, M.; Mikhalev, V.; Moretti, E.; Takahashi, H.; Pearce, M.

    2016-09-01

    PoGOLite is a balloon-borne hard X-ray polarimeter dedicated to the study of point sources. Compton scattered events are registered using an array of plastic scintillator units to determine the polarisation of incident X-rays in the energy range 20-240 keV. In 2013, a near circumpolar balloon flight of 14 days duration was completed after launch from Esrange, Sweden, resulting in a measurement of the linear polarisation of the Crab emission. Building on the experience gained from this Pathfinder flight, the polarimeter is being modified to improve performance for a second flight in 2016. Such optimisations, based on Geant4 Monte Carlo simulations, take into account the source characteristics, the instrument response and the background environment which is dominated by atmospheric neutrons. This paper describes the optimisation of the polarimeter and details the associated increase in performance. The resulting design, PoGO+, is expected to improve the Minimum Detectable Polarisation (MDP) for the Crab from 19.8% to 11.1% for a 5 day flight. Assuming the same Crab polarisation fraction as measured during the 2013 flight, this improvement in MDP will allow a 5σ constrained result. It will also allow the study of the nebula emission only (Crab off-pulse) and Cygnus X-1 if in the hard state.

  3. Synthesis, characterization and optical properties of NH{sub 4}Dy(PO{sub 3}){sub 4}

    SciTech Connect

    Chemingui, S.; Ferhi, M. Horchani-Naifer, K.; Férid, M.

    2014-09-15

    Polycrystalline powders of NH{sub 4}Dy(PO{sub 3}){sub 4} polyphosphate have been grown by the flux method. This compound was found to be isotopic with NH{sub 4}Ce(PO{sub 3}){sub 4} and RbHo(PO{sub 3}){sub 4}. It crystallizes in the monoclinic space group P2{sub 1/n} with unit cell parameters a=10.474(6) Å, b=9.011(4) Å, c=10.947(7) Å and β=106.64(3)°. The title compound has been transformed to triphosphate Dy(PO{sub 3}){sub 3} after calcination at 800 °C. Powder X-ray diffraction, infrared and Raman spectroscopies and the differential thermal analysis have been used to identify these materials. The spectroscopic properties have been investigated through absorption, excitation, emission spectra and decay curves of Dy{sup 3+} ion in both compounds at room temperature. The emission spectra show the characteristic emission bands of Dy{sup 3+} in the two compounds, before and after calcination. The integrated emission intensity ratios of the yellow to blue (I{sub Y}/I{sub B}) transitions and the chromaticity properties have been determined from emission spectra. The decay curves are found to be double-exponential. The non-exponential behavior of the decay rates was related to the resonant energy transfer as well as cross-relaxation between the donor and acceptor Dy{sup 3+} ions. The determined properties have been discussed as function of crystal structure of both compounds. They reveal that NH{sub 4}Dy(PO{sub 3}){sub 4} is promising for white light generation but Dy(PO{sub 3}){sub 3} is potential candidates in field emission display (FED) and plasma display panel (PDP) devices. - Graphical abstract: The CIE color coordinate diagrams showing the chromatic coordinates of Dy{sup 3+} luminescence in NH{sub 4}Dy(PO{sub 3}){sub 4} and Dy(PO{sub 3}){sub 3}. - Highlights: • The polycrystalline powders of NH{sub 4}Dy(PO{sub 3}){sub 4} and Dy(PO{sub 3}){sub 3} are synthesized. • The obtained powders are characterized. • The spectroscopic properties of Dy{sup 3+} ion

  4. THE STRUCTURE, MAGNETISM AND CONDUCTIVITY OF Li3V2(PO4)3: A THEORETICAL AND EXPERIMENTAL STUDY

    NASA Astrophysics Data System (ADS)

    Lin, Zhi-Ping; Zhao, Yu-Jun; Zhao, Yan-Ming

    2013-10-01

    In this paper, we present a combination of first-principles and experimental investigations on the structural, magnetic and electronic properties of monoclinic Li3V2(PO4)3. The change of dielectric constant indicates that the structural phase transition appear around the temperature 120°C. The first-principles calculation and magnetic measurement display that Li3V2(PO4)3 is a compound with weak ferromagnetism, with Curie constant of C = 0.004 and Curie temperature of 140 K. The experimental and theoretical results demonstrated that the Li3V2(PO4)3 is a typical semiconductor.

  5. Cubic KTi2(PO4)3 as electrode materials for sodium-ion batteries.

    PubMed

    Han, Jin; Xu, Maowen; Niu, Yubin; Jia, Min; Liu, Ting; Li, Chang Ming

    2016-12-01

    A novel cubic KTi2(PO4)3 is successfully synthesized via a facile hydrothermal method combined with a subsequent annealing treatment and further used as electrode material for sodium-ion batteries for the first time. For comparison, carbon-coated KTi2(PO4)3 obtained by a normal cane sugar-assisted method reveals superior electrochemical performances in sodium-ion battery. Besides of the high coulombic efficiency of nearly 100% after 100 cycles, a stable capacity of 112mAhg(-1) can be achieved at 0.5C after 100 cycles, and still maintains to 105mAhg(-1) after 500 cycles with capacity retention of approximately 90%. PMID:27552414

  6. Electromagnetic moments of odd-A Po193-203,211 isotopes

    NASA Astrophysics Data System (ADS)

    Seliverstov, M. D.; Cocolios, T. E.; Dexters, W.; Andreyev, A. N.; Antalic, S.; Barzakh, A. E.; Bastin, B.; Büscher, J.; Darby, I. G.; Fedorov, D. V.; Fedosseev, V. N.; Flanagan, K. T.; Franchoo, S.; Huber, G.; Huyse, M.; Keupers, M.; Köster, U.; Kudryavtsev, Yu.; Marsh, B. A.; Molkanov, P. L.; Page, R. D.; Sjödin, A. M.; Stefan, I.; Van Duppen, P.; Venhart, M.; Zemlyanoy, S. G.

    2014-03-01

    Hyperfine splitting parameters have been measured for the neutron-deficient odd-mass polonium isotopes and isomers Po193-203g,m, Po209,211. The measurement was performed at the ISOLDE (CERN) online mass separator using the in-source resonance ionization spectroscopy technique. The magnetic dipole moments μ and spectroscopic electric quadrupole moments QS have been deduced. Their implication for the understanding of nuclear structure in the vicinity of the closed proton shell at Z =82 and the neutron mid-shell at N =104 is discussed. For the most neutron-deficient nuclei (A =193,195,197), a deviation of μ and QS from the nearly constant values for heavier polonium nuclei was observed. Particle-plus-rotor calculations with static oblate deformation describe the electromagnetic moments for these nuclei well, provided a gradual increase of a mean deformation when going to lighter masses is assumed for the polonium nuclei with A <198.

  7. Determination of (210)Po in drinking water and urine samples using copper sulfide microprecipitation.

    PubMed

    Guérin, Nicolas; Dai, Xiongxin

    2014-06-17

    Polonium-210 ((210)Po) can be rapidly determined in drinking water and urine samples by alpha spectrometry using copper sulfide (CuS) microprecipitation. For drinking water, Po in 10 mL samples was directly coprecipitated onto the filter for alpha counting without any purification. For urine, 10 mL of sample was heated, oxidized with KBrO3 for a short time (∼5 min), and subsequently centrifuged to remove the suspended organic matter. The CuS microprecipitation was then applied to the supernatant. Large batches of samples can be prepared using this technique with high recoveries (∼85%). The figures of merit of the methods were determined, and the developed methods fulfill the requirements for emergency and routine radioassays. The efficiency and reliability of the procedures were confirmed using spiked samples.

  8. High-spin states in the five-valence-particle nucleus {sup 213}Po

    SciTech Connect

    Astier, Alain; Porquet, Marie-Genevieve

    2011-03-15

    Excited states in {sup 213}Po have been populated using the {sup 18}O+ {sup 208}Pb reaction at 85 MeV beam energy and studied with the Euroball IV {gamma} multidetector array. The level scheme has been built up to {approx}2.0 MeV excitation energy and spin I{approx}25/2({h_bar}/2{pi}) from the triple {gamma} coincidence data. Spin and parity values of several yrast states have been assigned from the {gamma} angular properties. The configurations of the yrast states are discussed using results of empirical shell-model calculations and by analogy with the neighboring nuclei. The spin and parity values of several low-spin states of {sup 213}Po previously identified from the {beta} decay of {sup 213}Bi are revised.

  9. Estimation of Kd of lead and (210)Po in 11 soils from India.

    PubMed

    Maity, Sukanta; Pandit, G G

    2014-12-01

    The fate of contaminant transport is often estimated using the distribution (partition) coefficient, Kd. It is a measure of sorption of contaminants to soil. As Kd is element, soil type and ground water dependent, chemical characterization of soil and ground water of the particular site is essential. In this study, soil and ground water samples from different locations around India were collected. The soil samples were physically characterized and pH, CaCO3, cation exchange capacity (CEC), organic matter and organic carbon were determined. Equilibration time for lead and (210)Po were estimated with respect to contact time and were found to be 28 and 72 h respectively. The Kd of lead varied from 6700 to 31,000 L/kg with a geometric mean of 15,200 L/kg, and for (210)Po from 1400 to 8700 L/kg with a geometric mean of 3700 L/kg.

  10. Laser Spectroscopy of GdPO4 . nH2O:Eu Nanomaterials.

    PubMed

    Lu, Shaozhe; Zhang, Jiahua; Zhang, Jishen; Shulin, Zhang E; Zhao, Haifeng; Luo, Yongshi

    2016-04-01

    One-dimensional GdPO4 . nH2O:Eu nanowires and nanorods of different sizes and the same structure were synthesized by hydrothermal method. Nanowire and nanorods had width and length of about 10 nm/50 nm and 80 nm/1 µm, respectively. Adjusting reaction system PH value by adding alkali metal NaOH, the size and shape of the product can be tuned. The high resolution spectra, excitation spectra, and laser selective excitation spectra at low temperature were determined. Nanorod compared with nanowire, photoluminescence was enhanced, and the excitation spectrum and laser selective excitation spectra were broadened. These results suggest that Eu3+ in GdPO4 . nH20 nanorod and nanowire were located in different local environments. PMID:27451675

  11. Minimal model for the frustrated spin ladder system BiCu2PO6

    NASA Astrophysics Data System (ADS)

    Splinter, Leanna; Drescher, Nils A.; Krull, Holger; Uhrig, Götz S.

    2016-10-01

    To establish the microscopic model of the compound BiCu2PO6 is a challenging task. Inelastic neutron scattering experiments showed that the dispersion of this material is nondegenerate suggesting the existence of anisotropic interactions. Here we present a quantitative description of the excitation spectrum for BiCu2PO6 on the one-particle level. The solution of the isotropic frustrated spin ladder by continuous unitary transformations is the starting point of our approach. Further couplings such as isotropic interladder couplings and anisotropic interactions are included on the mean-field level. Our aim is to establish a minimal model built on the symmetry-allowed interactions and to find a set of parameters which allows us to describe the low-energy part of the dispersion without assuming unrealistic couplings.

  12. Working with Local School Districts: A Possible Model for ROSS E/PO Programs

    NASA Astrophysics Data System (ADS)

    Grier, J. A.; Dussault, M. E.; Spaulding, K. L.; Reinfeld, E.; Steel, S. J.; Gould, R. R.

    2004-08-01

    We designed and implemented an effective professional development experience for the science teachers of the Cambridge Public School system. The experience included curriculum consultations, a series of workshops, night observing sessions, presentations by content experts, demonstrations and modeling, as well as activities directly applicable to the teachers' classrooms. Feedback and evaluation data from teachers and professional development coordinators in the system indicated a very positive response, and direct application of material learned in the workshops to the classroom setting. Several key strategies combined to make this effort successful, cost effective and high leverage. These strategies can be exported in whole or in part to other prospective E/PO programs to increase their potential level of success. The scope of the program was well suited to a ROSS E/PO level effort. This work was funded under the NASA Office of Space Science Education and Outreach Program.

  13. Knemidocoptes sp. on wild passerines at the Mai Po Nature Reserve, Hong Kong.

    PubMed

    Mainka, S A; Melville, D S; Galsworthy, A; Black, S R

    1994-04-01

    Free-ranging passerine birds banded at the Mai Po Nature Reserve, Hong Kong, were affected with a skin disease characterized by crusty, proliferative lesions on legs, feet and beaks. Based on retrospective examination of 1990 to 1992 banding records, 83 of 16,353 birds and 5 of 161 species banded at Mai Po were identified as having these lesions. Eurasian tree sparrows (Passer montanus) were most commonly affected (58 of 411 birds) although 19 of 428 black-faced buntings (Emberiza pusilla), 3 of 92 spotted doves (Streptopelia chinensis), and 2 of 616 eastern great reed warblers (Acrocephalus orientalis) also had clinical signs of infestation. Adult Eurasian tree sparrows were affected more often than juveniles and males were affected more often than females. Lesions on juveniles usually were on the feet while on adults lesions also were found on legs and beak. The effects of this parasitic infestation on body weight of wild Eurasian tree sparrows was not significant.

  14. The dipole moment of the PO radical determined by microwave spectroscopy

    NASA Astrophysics Data System (ADS)

    Kanata, Hiroyuki; Yamamoto, Satoshi; Saito, Shuji

    1988-09-01

    The Stark effect of the PO radical in the X2Π, state was measured for two rotational transitions in the millimeter-wave region: ω = {3}/{2}, J = {13}/{2}- {11}/{2}, F = 7-6, 6-5 (285 GHz) and ω = {3}/{2}, J = {11}/{2}- {9}/{2}, F = 6-5, 5-4 (242 GHz). The MF components of the spectral lines were not resolved in electric fields below about 80 V/cm, and the Stark effect was observed as a change of the breadth of the lineshape. The dipole moment of PO was determined to be 1.88(7) D by a numerical simulation of the lineshape, where the error is three standard deviations.

  15. Evidence for Nodal Superconductivity in LaFePO from Scanning SQUID Susceptometry

    SciTech Connect

    Hicks, Clifford W.; Lippman, Thomas M.; Huber, Martin E.; Analytis, James G.; Chu, Jiun-Haw; Erickson, Ann S.; Fisher, Ian R.; Moler, Kathryn A.; /Stanford U., Geballe Lab. /SLAC

    2009-04-13

    We measure changes in the penetration depth {lambda} of the T{sub c} {approx} 6 K superconductor LaFePO. In the process scanning SQUID susceptometry is demonstrated as a technique for accurately measuring local temperature-dependent changes in {lambda}, making it ideal for studying early or difficult-to-grow materials. {lambda} of LaFePO is found to vary linearly with temperature from 0.36 to {approx} 2 K, with a slope of 143 {+-} 15 {angstrom}/K, suggesting line nodes in the superconducting order parameter. The linear dependence up to {approx} T{sub c}/3 is similar to the cuprate superconductors, indicating well-developed nodes.

  16. Cubic KTi2(PO4)3 as electrode materials for sodium-ion batteries.

    PubMed

    Han, Jin; Xu, Maowen; Niu, Yubin; Jia, Min; Liu, Ting; Li, Chang Ming

    2016-12-01

    A novel cubic KTi2(PO4)3 is successfully synthesized via a facile hydrothermal method combined with a subsequent annealing treatment and further used as electrode material for sodium-ion batteries for the first time. For comparison, carbon-coated KTi2(PO4)3 obtained by a normal cane sugar-assisted method reveals superior electrochemical performances in sodium-ion battery. Besides of the high coulombic efficiency of nearly 100% after 100 cycles, a stable capacity of 112mAhg(-1) can be achieved at 0.5C after 100 cycles, and still maintains to 105mAhg(-1) after 500 cycles with capacity retention of approximately 90%.

  17. Synthesis, characterization, and electrochemical studies of chemically synthesized NaFePO{sub 4}

    SciTech Connect

    Sun, Ann; Beck, Faith R; Haynes, Daniel; Poston, James A; Narayanana, S R; Kumta, Prashant N; Manivannan, A

    2012-12-01

    NaFePO{sub 4} is a naturally occurring mineral known as maricite. This compound has not been well characterized or examined for its potential use in battery applications. In the present study, NaFePO{sub 4} has been synthesized via the Pechini process with the resulting sample being characterized by X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Electrochemical properties have been investigated for possible application as a cathode in sodium-ion batteries. Electrodes of these materials were tested in coin cells using LiPF{sub 6} as the electrolyte and lithium metal as the counter electrode. Constant current cycling, cyclic voltammetry, and in situ frequency response analyses were performed. The results obtained demonstrate constant capacity or progressive increase in capacity with the consistently low internal resistance exhibited over consecutive cycles indicating possible application as a lithium analog in Na-ion batteries.

  18. Concentrations of U and Po in animal feed supplements, in poultry meat and in eggs

    SciTech Connect

    Izak-Biran, T.; Schlesinger, T.; Weingarten, R.; Even, O.; Shamai, Y.; Israeli, M.

    1989-03-01

    The present study was undertaken to assess the contribution of phosphate feed supplements to the radiation exposure of the population in Israel. The phosphates usually contain appreciable quantities of U and its daughters and the actual exposure of human consumers depends, to a very large extent, on the degree of equilibrium of the decay chain in the feed and through the metabolic process. The concentrations of /sup 238/U, /sup 234/U, /sup 226/Ra and /sup 210/Po (/sup 210/Pb) in poultry feed supplements and in chicken meat (breasts, thighs) and organs (livers, spleens, gizzards) as well as in eggs were determined. From the results, the transfer coefficients of U and Po in chicken meat and in eggs were calculated. The effective dose equivalent to the Israeli population due to the consumption of poultry products which accounts for approximately 70% of all meat consumed in Israel is assessed to be 0.04 mSv y-1.

  19. Structural transformation of Li 2CoPO 4F upon Li-deintercalation

    NASA Astrophysics Data System (ADS)

    Khasanova, Nellie R.; Gavrilov, Alexey N.; Antipov, Evgeny V.; Bramnik, Kirill G.; Hibst, Hartmut

    Electrochemical performance and structural properties of the high-voltage cathode material Li 2CoPO 4F have been investigated. The cyclic voltammetry and coulometry under potential step mode in the voltage range 3.0-5.1 V vs. Li revealed a structural transformation at potentials above 4.8 V. This transformation occurring upon Li-extraction appears to be irreversible: the subsequent Li-insertion does not result in restoration of the initial structure, but takes place within a new "modified" framework. According to the structure refinement this modification involves the mutual rotations of (CoO 4F 2) octahedra and (PO 4) tetrahedra accompanied by the considerable unit cell expansion which is expected to enhance the Li-transport upon subsequent cycling. The new framework demonstrates a reversible Li-insertion/extraction in a solid-solution regime with stabilized discharge capacity at around 60 mAh g -1.

  20. Co-synthesis of LiFePO4 and Carbon Nanotubes

    SciTech Connect

    Wilcox, James; Doeff, Marca M.

    2006-05-26

    The rate capabilities of LiFePO{sub 4} composites are dependent on the structure of the carbon that coats the powders, formed during co-calcination with carbon containing precursors. The addition of readily decomposed pyromellitic acid and graphitization catalysts such as ferrocene during synthesis results in coatings with low D/G (disordered/graphene) ratios, while maintaining the carbon content of the powders below 2 wt. %. This is important to avoid adversely affecting the tap density. The good correlation between the pressed pellet conductivities of the LiFePO{sub 4}/C composites and their rate capability in lithium cells is further confirmation of the importance of the carbon structure, because graphitic carbons generally have higher conductivities than disordered ones.

  1. Strong Nanocomposites with Ca, PO4, and F Release for Caries Inhibition

    PubMed Central

    Xu, H.H.K.; Weir, M.D.; Sun, L.; Moreau, J.L.; Takagi, S.; Chow, L.C.; Antonucci, J.M.

    2010-01-01

    This article reviews recent studies on: (1) the synthesis of novel calcium phosphate and calcium fluoride nanoparticles and their incorporation into dental resins to develop nanocomposites; (2) the effects of key microstructural parameters on Ca, PO4, and F ion release from nanocomposites, including the effects of nanofiller volume fraction, particle size, and silanization; and (3) mechanical properties of nanocomposites, including water-aging effects, flexural strength, fracture toughness, and three-body wear. This article demonstrates that a major advantage of using the new nanoparticles is that high levels of Ca, PO4, and F release can be achieved at low filler levels in the resin, because of the high surface areas of the nanoparticles. This leaves room in the resin for substantial reinforcement fillers. The combination of releasing nanofillers with stable and strong reinforcing fillers is promising to yield a nanocomposite with both stress-bearing and caries-inhibiting capabilities, a combination not yet available in current materials. PMID:19948941

  2. Determination of (210)Po in drinking water and urine samples using copper sulfide microprecipitation.

    PubMed

    Guérin, Nicolas; Dai, Xiongxin

    2014-06-17

    Polonium-210 ((210)Po) can be rapidly determined in drinking water and urine samples by alpha spectrometry using copper sulfide (CuS) microprecipitation. For drinking water, Po in 10 mL samples was directly coprecipitated onto the filter for alpha counting without any purification. For urine, 10 mL of sample was heated, oxidized with KBrO3 for a short time (∼5 min), and subsequently centrifuged to remove the suspended organic matter. The CuS microprecipitation was then applied to the supernatant. Large batches of samples can be prepared using this technique with high recoveries (∼85%). The figures of merit of the methods were determined, and the developed methods fulfill the requirements for emergency and routine radioassays. The efficiency and reliability of the procedures were confirmed using spiked samples. PMID:24906041

  3. Data catalog for JPL Physical Oceanography Distributed Active Archive Center (PO.DAAC)

    NASA Technical Reports Server (NTRS)

    Digby, Susan

    1995-01-01

    The Physical Oceanography Distributed Active Archive Center (PO.DAAC) archive at the Jet Propulsion Laboratory contains satellite data sets and ancillary in-situ data for the ocean sciences and global-change research to facilitate multidisciplinary use of satellite ocean data. Geophysical parameters available from the archive include sea-surface height, surface-wind vector, surface-wind speed, surface-wind stress vector, sea-surface temperature, atmospheric liquid water, integrated water vapor, phytoplankton pigment concentration, heat flux, and in-situ data. PO.DAAC is an element of the Earth Observing System Data and Information System and is the United States distribution site for TOPEX/POSEIDON data and metadata.

  4. Measurements of the half-life of 214Po and 218Rn using digital electronics.

    PubMed

    Suliman, G; Pommé, S; Marouli, M; Van Ammel, R; Jobbágy, V; Paepen, J; Stroh, H; Apostolidis, C; Abbas, K; Morgenstern, A

    2012-09-01

    The half-lives of (214)Po and (218)Rn have been measured. The radionuclides were produced in the decay of a (230)U source and the emitted alpha-particles were measured in nearly-2π geometry with an ion-implanted planar silicon detector. The data acquisition was performed with a digitiser operated in list mode, saving the energy and time of detection (10 ns precision timestamp) of each event. The half-lives were deduced from the time differences between the alpha-decays populating the nuclide of interest and those corresponding to its decay. Different methods were applied, based on delayed coincidence counting and time-interval distribution analysis. The resulting half-lives are 33.75 (15) ms for (218)Rn and 164.2 (6) μs for (214)Po, both in agreement with some of the literature values, and obtained with higher precision in this work.

  5. Fungal spores and pollen in particulate matter collected during agricultural activities in the Po Valley (Italy).

    PubMed

    Telloli, Chiara; Chicca, Milvia; Leis, Marilena; Vaccaro, Carmela

    2016-08-01

    Airborne particulate matter (PM) containing fungal spores and pollen grains was sampled within a monitoring campaign of wheat threshing, plowing and sowing agricultural operations. Fungal spores and pollen grains were detected and identified on morphological basis. No studies were previously available about fungal spore and pollen content in agricultural PM in the Po Valley. Sampling was conducted in a Po Valley farmland in Mezzano (Ferrara, Italy). The organic particles collected were examined by scanning electron microscopy with energy dispersive X-ray spectrometer. Fungal spores and pollen grains were identified when possible at the level of species. The most frequent components of the organic particles sampled were spores of Aspergillus sp., which could represent a risk of developing allergies and aspergillosis for crop farmers. PMID:27521955

  6. Methyl-phospho-nic acid, CH3PO(OH)2.

    PubMed

    Reuter, Hans; Reichelt, Martin

    2014-03-01

    The asymmetric unit of the title compound, CH5O3P, contains two independent mol-ecules with nearly identical bond lengths and angles. In the crystal, each of the mol-ecules acts as acceptor (P=O) and donor (P-OH) of four hydrogen bonds to three adjacent mol-ecules, resulting in the formation of two different bilayers (one for each mol-ecule) stacked perpendicular to the a axis in the crystal.

  7. Polymorphism and phase transitions of K_3Lu(PO_4)_2

    NASA Astrophysics Data System (ADS)

    Farmer, J. Matt; Boatner, Lynn A.; Chakoumakos, Bryan C.; Mandrus, David; Jin, Rongying

    2001-03-01

    Alkali lanthanide double phosphates have been studied for uses as long-wavelength scintillators for γ-ray detection using Si photodiodes. This family of compounds exhibits layered crystal structures, in the sequence lanthanide, phosphate alkali, alkali, alkali - phosphate. Current research has focused on K_3Lu(PO_4)_2. At room temperature, this compound is hexagonal, P 3 space group symmetry. The Lu ion is six-coordinated to the oxygen atoms of the phosphate groups. Our group has recently characterized two lower-temperature phases of K_3Lu(PO_4)2 using single-crystal XRD and powder neutron diffraction. The first transition occurs at 230 K, with a transformation to monoclinic P 2_1/m space group symmetry, and the Lu still retains six coordination. Another transition occurs at 130 K, with a small change in the cell volume, keeping the same P 2_1/m space group symmetry; however, one of the phosphate groups rotates to increase the coordination of the Lu ion to seven. This new structure is isostructural with the room-temperature form of K_3Yb(PO_4)_2. A heat capacity versus temperature study of K_3Lu(PO_4)2 confirms the transformations and indicates a large thermal hysteresis as the crystals are thermally cycled between 15 and 295 K. Research sponsored by the U.S. Department of Energy under contract DE-AC05-00OR22725 with the Oak Ridge National Laboratory, managed by UT-Battelle, LLC.

  8. Ionic transport properties of LiCoPO 4 cathode material

    NASA Astrophysics Data System (ADS)

    Prabu, M.; Selvasekarapandian, S.; Kulkarni, A. R.; Karthikeyan, S.; Hirankumar, G.; Sanjeeviraja, C.

    2011-09-01

    LiCoPO 4 has been prepared by the Pechini-type polymerizable precursor method. The formation of the compound is confirmed by XRD analysis. Ion transport mechanism has been analyzed using the AC impedance technique. The conductivity parameters such as ion hopping frequency ( ωp) and the charge carrier concentration term (K) have been calculated using Almond and West formalisms. The conductivity relaxation time ( τc) is calculated from the peak frequency of the modulus spectra.

  9. Nurturing The STEM Pipeline: Graduate Student Leadership In NIRCam's Ongoing E/PO Mission For JWST

    NASA Astrophysics Data System (ADS)

    Schlingman, Wayne M.; Stock, N.; Teske, J.; Tyler, K.; Biller, B.; Donley, J.; Hedden, A.; Knierman, K.; Young, P.

    2011-01-01

    The Astronomy Camp for Girl Scout Leaders is an education and public outreach (E/PO) program offered by the science team of the Near-InfraRed Camera (NIRCam) for NASA's 6.5-meter James Webb Space Telescope (JWST). Since 2003, astronomy graduate students have helped design and lead biannual "Train the Trainer” workshops for adults from the Girl Scouts of the USA (GSUSA), engaging these trainers in the process of scientific inquiry and equipping them to host astronomy-related activities at the troop level. These workshops have helped revise the national GSUSA badge curriculum and directly benefitted thousands of young girls of all ages, not only in general science and math education but also in specific astronomical and technological concepts relating to JWST. To date, nine graduate students have become members of NIRCam's E/PO team. They have developed curriculum and activities used to teach concepts in stellar nucleosynthesis, lookback time, galaxy classification, etc. They have also contributed to the overall strategic approach and helped lead more general activities in basic astronomy (night sky, phases of the Moon, the scale of the Solar System and beyond, stars, galaxies, telescopes, etc.) as well as JWST-specific research areas in extrasolar planetary systems and cosmology, to pave the way for girls and women to understand the first images from JWST. The resulting experience has empowered these students to propose and to develop their own E/PO programs after graduation as postdocs and young faculty. They also continue as part of NIRCam's growing worldwide network of 160 trainers teaching young women essential STEM-related concepts using astronomy, the night sky environment, applied math, engineering, and critical thinking. NIRCam and its E/PO program are funded by NASA under contract NAS5-02105.

  10. Molecular structure of (AgPO3)1-x (AgI)x glasses

    NASA Astrophysics Data System (ADS)

    Novita, D.

    2005-03-01

    Melt-quenched AgPO3 glasses were synthesized by dry ( Ag3PO4 + P2O5, prep. 1) and wet (NH4H2PO4 + AgNO3, prep. 2) routes. Glass transitions were examined in MDSC at a scan rate of 3^oC/min. Prep. 1 samples display bimodal glass transition temperatures, with Tg^low = 220^oC and Tg^high = 238^oC and with the Tg^low endotherm higher in strength than the Tg^high one. In contrast, prep. 2 samples show a single Tg = 203^oC that is significantly lower in temperature. These results are consistent with the notion that prep. 2 probably yields samples with bonded water while prep 1 gives pure AgPO3 glasses that are intrinsically phase separated. The nature of the two phases in the latter is less obvious at present, but we note that upon alloying AgI, the additive selectively bonds in the Tg^low phase at low x (<0.20) with Tg^low steadily decreasing, and with the Tg^high phase remaining largely unaffected. At higher x (>0.20) a major structural reorganization occurs, and we observe the opening of a reversibility window in the 0.22 < x < 0.37 range. As in the chalcogenides, we identify the window with the intermediate phase with glasses at x < 0.20 stressed-rigid, while those at x > 0.37 as floppy. A percolation threshold for electrical conduction occurs^1 near x ˜ 0.3 and falls in the reversibility window as expected. 1. M. Mangion and G.P. Johari, Phys. Rev. B36, 8845 (1987) Supported by NSF grant DMR 04-56472

  11. Charge radii of odd-A191-211Po isotopes

    NASA Astrophysics Data System (ADS)

    Seliverstov, M. D.; Cocolios, T. E.; Dexters, W.; Andreyev, A. N.; Antalic, S.; Barzakh, A. E.; Bastin, B.; Büscher, J.; Darby, I. G.; Fedorov, D. V.; Fedoseyev, V. N.; Flanagan, K. T.; Franchoo, S.; Fritzsche, S.; Huber, G.; Huyse, M.; Keupers, M.; Köster, U.; Kudryavtsev, Yu.; Marsh, B. A.; Molkanov, P. L.; Page, R. D.; Sjødin, A. M.; Stefan, I.; Van de Walle, J.; Van Duppen, P.; Venhart, M.; Zemlyanoy, S. G.

    2013-02-01

    Isotope shifts have been measured for the odd-A polonium isotopes 191-211Po and changes in the nuclear mean square charge radii δ have been deduced. The measurements were performed at CERN-ISOLDE using the in-source resonance-ionization spectroscopy technique. The combined analysis of these data and our recent results for even-A polonium isotopes indicates an onset of deformation already at 197,198Po, when going away from stability. This is significantly earlier than was suggested by previous theoretical and experimental studies of the polonium isotopes. Moreover and in contrast to the mercury isotopes, where a strong odd-even staggering of the charge radii of the ground states was observed by approaching the neutron mid-shell at N = 104, no such effect is present in polonium down to 191Po. Consequently the charge radii of both isomeric and ground states of the odd-A polonium isotopes follow the same trend as the even-A isotopes.

  12. The First Detections of the Key Prebiotic Molecule PO in Star-forming Regions

    NASA Astrophysics Data System (ADS)

    Rivilla, V. M.; Fontani, F.; Beltrán, M. T.; Vasyunin, A.; Caselli, P.; Martín-Pintado, J.; Cesaroni, R.

    2016-08-01

    Phosphorus is a crucial element in biochemistry, in particular the P‑O bond, which is key in the formation of the backbone of deoxyribonucleic acid. So far, PO has only been detected toward the envelope of evolved stars, but never toward star-forming regions. We report the first detection of PO toward two massive star-forming regions, W51 e1/e2 and W3(OH), using data from the IRAM 30 m telescope. PN has also been detected toward the two regions. The abundance ratio PO/PN is 1.8 and 3 for W51 and W3(OH), respectively. Our chemical model indicates that the two molecules are chemically related and are formed via gas-phase ion–molecule and neutral–neutral reactions during cold collapse. The molecules freeze out onto grains at the end of the collapse and desorb during the warm-up phase once the temperature reaches ˜35 K. Similar abundances of the two species are expected during a period of ˜5 × 104 yr at the early stages of the warm-up phase, when the temperature is in the range 35–90 K. The observed molecular abundances of 10‑10 are predicted by the model if a relatively high initial abundance of 5 × 10‑9 of depleted phosphorus is assumed.

  13. Spatial variability of δ18O-PO4 in soils.

    NASA Astrophysics Data System (ADS)

    Granger, Steve; Blackwell, Martin; Tamburini, Federica; Guo, Rongrong; Peukert, Sabine; McGrath, Steve

    2014-05-01

    There is growing interest in the potential for using the δ18OPO4 values of different phosphate sources in the environment to enable identification of sources of phosphate in surface waters. The basis of the study is the belief that different sources of PO4 may have different δ18O values. One of the primary sources of PO4 in runoff from agricultural land is the soil itself. Therefore, in order to account for the PO4 derived from soils in surface waters, it is vital that the degree of spatial variability of its δ18O isotopic values are known, in order that suitable soil sampling approaches can be taken when assessing the soil as a source in future studies. A spatial study of the variability of the δ18OPO4 variability of soils collected from a grazed pasture on the North Wyke Farm Platform was carried out incorporating grid-sampling at a range of spatial scales. Results show that variability across a range of scales is minimal, meaning that, in this case, a relatively small number of samples would be required in order to identify accurately the mean δ18OPO4 value of the soil. This study represents an important contribution towards the methodological development studies required in this field of research in order that the full potential of the δ18OPO4 technique for biological and environmental research can be achieved.

  14. PoMo: An Allele Frequency-Based Approach for Species Tree Estimation

    PubMed Central

    De Maio, Nicola; Schrempf, Dominik; Kosiol, Carolin

    2015-01-01

    Incomplete lineage sorting can cause incongruencies of the overall species-level phylogenetic tree with the phylogenetic trees for individual genes or genomic segments. If these incongruencies are not accounted for, it is possible to incur several biases in species tree estimation. Here, we present a simple maximum likelihood approach that accounts for ancestral variation and incomplete lineage sorting. We use a POlymorphisms-aware phylogenetic MOdel (PoMo) that we have recently shown to efficiently estimate mutation rates and fixation biases from within and between-species variation data. We extend this model to perform efficient estimation of species trees. We test the performance of PoMo in several different scenarios of incomplete lineage sorting using simulations and compare it with existing methods both in accuracy and computational speed. In contrast to other approaches, our model does not use coalescent theory but is allele frequency based. We show that PoMo is well suited for genome-wide species tree estimation and that on such data it is more accurate than previous approaches. PMID:26209413

  15. BiPo: A dedicated radiopurity detector for the SuperNEMO experiment

    SciTech Connect

    Gómez, H.; Collaboration: SuperNEMO Collaboration; and others

    2013-08-08

    New generation experiments in Astroparticle Physics need to operate in really restrictive background conditions, which implies the use of high radiopure materials for the experimental setup construction. For this reason the screening of the materials with enough sensitivity has become a challenge that sometimes cannot be afforded with standard techniques like Germanium detector spectroscopy. BiPo is a dedicated detector, that operates in the Canfranc Underground Laboratory, designed to measure the radiopurity, mainly of the ββ sources of the SuperNEMO experiment, by the detection of BiPo events. It is composed of two modules with 40 optical lines each one, registering the energy and the time of the emitted particles. The well known features of the BiPo events (delayed coincidence between an electron and an alpha particle) facilitate the discrimination of other background events that could entangle the expected signal. In addition, the geometry of the detector, with an active area of around 3.6 m{sup 2}, has been optimized to reach the necessary sensitivity levels for the SuperNEMO source foils in the shortest time possible. Preliminary results of background measurements and calibrations taken since summer 2012 shows that the required sensitivity for the measurements of the source foils could be reached in few months. Routine measurements of samples are already started being an important point for the SuperNEMO source foils construction.

  16. Factors Influencing the Quality of Carbon Coatings onLiFePO4

    SciTech Connect

    Wilcox, James D.; Doeff, Marca M.; Marcinek, Marek; Kostecki,Robert

    2006-10-11

    Several LiFePO4/C composites were prepared and characterizedelectrochemically in lithium half-cells. Pressed pellet conductivitiescorrelated well with the electrochemical performance in lithiumhalf-cells. It was found that carbon structural factors such as sp2/sp3,D/G, and H/C ratios, as determined by Raman spectroscopy and elementalanalysis, influenced the conductivity and rate behavior strongly. Thestructure of the residual carbon could be manipulated through the use ofadditives during LiFePO4 synthesis. Increasing the pyromellitic acid (PA)content in the precursor mix prior to calcination resulted in asignificant lowering of the D/G ratio and a concomitant rise in thesp2/sp3 ratio of the carbon. Addition of both iron nitrate and PAresulted in higher sp2/sp3 ratios without further lowering the D/Gratios, or increasing carbon contents. The best electrochemical resultswere obtained for LiFePO4 processed with both ferrocene and PA. Theimprovement is attributed to better decomposition of the carbon sources,as evidenced by lower H/C ratios, a slight increase of the carbon content(still below 2 wt. percent), and more homogeneous coverage. A discussionof the influence of carbon content vs. structural factors on thecomposite conductivities and, by inference, the electrochemicalperformance, is included.

  17. The Legacy of NASA Astrophysics E/PO: Scientist Engagement and Higher Education

    NASA Astrophysics Data System (ADS)

    Manning, Jim; Smith, Denise A.; Meinke, Bonnie; Lawton, Brandon; Schulz, Gregory; Bartolone, Lindsay; Bianchi, Luciana; NASA SMD Astrophysics E/PO Community

    2016-01-01

    For the past six years, NASA's Science Mission Directorate has coordinated the work of its mission- and program-embedded education and public outreach (E/PO) efforts through four forums representing its four science divisions. The Astrophysics forum, as the others, has built on the long-standing mission E/PO 1% allocation and embedded scientist/educator partnerships to encourage and coordinate collaborative efforts to make the most efficient and effective use of NASA resources, personnel, data and discoveries in leveraged ways, in support of the nation's science education. Two of the priorities established early in the forum's period of activity were to enhance scientist engagement in E/PO and to coordinate the community in providing useful higher education resources based on determined needs. This presentation will highlight some of the achievements for these two priorities over the past six years, how the products and efforts are being preserved, and how they can continue to be accessed as NASA SMD transitions to a new Education and Communication landscape. The work constitutes an ongoing legacy--a firm foundation on which the new structure of NASA SMD Education efforts will go forward.

  18. PoPoolationTE2: Comparative Population Genomics of Transposable Elements Using Pool-Seq

    PubMed Central

    Kofler, Robert; Gómez-Sánchez, Daniel; Schlötterer, Christian

    2016-01-01

    The evolutionary dynamics of transposable elements (TEs) are still poorly understood. One reason is that TE abundance needs to be studied at the population level, but sequencing individuals on a population scale is still too expensive to characterize TE abundance in multiple populations. Although sequencing pools of individuals dramatically reduces sequencing costs, a comparison of TE abundance between pooled samples has been difficult, if not impossible, due to various biases. Here, we introduce a novel bioinformatic tool, PoPoolationTE2, which is specifically tailored for the comparison of TE abundance among pooled population samples or different tissues. Using computer simulations, we demonstrate that PoPoolationTE2 not only faithfully recovers TE insertion frequencies and positions but, by homogenizing the power to identify TEs across samples, it provides an unbiased comparison of TE abundance between pooled population samples. We anticipate that PoPoolationTE2 will greatly facilitate the analysis of TE insertion patterns in a broad range of applications. PMID:27486221

  19. Estimation of past radon exposure to indoor radon from embedded (210)Po in household glass.

    PubMed

    Gusain, G S; Rautela, B S; Ramola, R C

    2012-11-01

    In the present investigation, the surface-deposited polonium activities were measured in houses in the Ukhimath region of Garhwal Himalaya, India. The surface-deposited (210)Po activity concentrations were found to vary from 0.7 to 15.40 Bq m(-2) with an average of 5.95 Bq m(-2). The radon concentration estimated on the basis of (210)Po activity was found to vary from 0.29 to 700 Bq m(-3) with an average value 242 Bq m(-3). The contemporary radon concentration in the area was found to vary from 13 to 181 Bq m(-3) with an average of 46 Bq m(-3). The annual effective dose due to (210)Po activity in houses in the Garhwal Himalaya region was found to vary from 0.61 to 13.33 mSv with an average of 5.15 mSv. Some worldwide studies have shown the relation between the increased risk of lung cancer and smoking habits. Data on smoking have also been collected from the same dwellings. The significance of this work is also discussed in detail from a radiation protection point of view.

  20. Low temperature phase transition and crystal structure of CsMgPO4

    NASA Astrophysics Data System (ADS)

    Orlova, Maria; Khainakov, Sergey; Michailov, Dmitriy; Perfler, Lukas; Langes, Christoph; Kahlenberg, Volker; Orlova, Albina

    2015-01-01

    CsMgPO4 doped with radioisotopes is a promising compound for usage as a radioactive medical source. However, a low temperature phase transition at temperatures close to ambient conditions (~-40 °C) was observed. Information about such kind of structural changes is important in order to understand whether it can cause any problem for medical use of this compound. The phase transition has been investigated in detail using synchrotron powder diffraction, Raman spectroscopy and DFT calculations. The structure undergoes a transformation from an orthorhombic modification, space group Pnma (RT phase) to a monoclinic polymorph, space group P21/n (LT phase). New LT modification adopts similar to RT but slightly distorted unit cell: a=9.58199(2) Å, b=8.95501(1) Å, c=5.50344(2) Å, β=90.68583(1)°, V=472.198(3) Å3. CsMgPO4 belongs to the group of framework compounds and is made up of strictly alternating MgO4- and PO4-tetrahedra sharing vertices. The cesium counter cations are located in the resulting channel-like cavities. Upon the transformation a combined tilting of the tetrahedra is observed. A comparison with other phase transitions in ABW-type framework compounds is given.

  1. Synthesis, Characterization and Luminescence Properties of Rod-Like LaPO4:Eu3+ Nanostructures.

    PubMed

    Peng, Li; Yun, Liu; Xiaolei, Shi; Yaxin, Guo; Gangqiang, Zhu

    2016-04-01

    Large-scale, rod-like nanostructures of LaPO4:Eu3+ phosphors were synthesized using a simple hydrothermal method. The phase composition, structure and morphology of the final products were characterized by XRD, FE-SEM and TEM. Highly crystalline material was obtained as confirmed by X-ray powder diffraction measurements. The FE-SEM and TEM observations indicate that the obtained LaPO4:Eu3+ nanorods have a diameter of about 10-20 nm, and a length of about 100-600 nm. Meanwhile, the excitation and emission spectra of the products at room temperature were measured using a fluorescence spectrometer. The effects of pH and Eu3+-doping on the morphology and luminescence properties of the as-prepared powders were investigated. The photoluminescence (PL) spectra show that the emission intensity of the LaPO4:Eu3+ phosphors improved with increases in concentrations of Eu3+ from 3 mol% to 14 mol%, and then decreased for higher concentrations. PMID:27451758

  2. Technologically enhanced 210Pb and 210Po in iron and steel industry.

    PubMed

    Khater, Ashraf E M; Bakr, Wafaa F

    2011-05-01

    Iron and steel manufacture has been ranked as the largest industrial source of environmental contamination in the USA; the wastes generated in their production processes contain heavy elements that can be a source of contamination, and natural radionuclides that can produce an occupational and/or public radiological impact. In this work the potential occupational effective dose rate (μSv/y) due to inhalation in four integrated steel-making factories from Egypt has been evaluated, by assuming a well defined scenario and with basis in the (210)Pb and (210)Po activity concentrations determined in ore and wastes collected in the aforementioned factories. Activity concentrations, in Bq/kg, of (210)Pb and (210)Po, and leachable Pb and Fe were measured using gamma-ray spectrometry based on HPGe detector, alpha particle spectrometry based on PIPS detector, and inductively coupled plasma-mass spectrometry (ICP-MS). Levels of (210)Pb and (210)Po in the range of

  3. Structure and spectroscopic properties of (Y, Eu)(PO3)3 polyphosphate red phosphors

    NASA Astrophysics Data System (ADS)

    Zhang, Xinguo; Chen, Peican; Wang, Zizhou; Zhou, Liya; Zhou, Fangxiang

    2016-08-01

    A series of orange-red emitting phosphor Y(PO3)3: xEu3+ (x = 0.1-1.0) was prepared by a solid-state reaction route. The phosphors were characterized by X-ray diffraction (XRD) and photoluminescence (PL) as well as decay lifetimes. Studies revealed the phase transfer from monoclinic to orthorhombic when Y3+ is totally replaced by Eu3+, and expansion of the unit cell occurs with increasing Eu3+ doped content. The PL spectra show that the phosphors Y(PO3)3: xEu3+ can be effectively excited by near ultraviolet (n-UV) light, and exhibit strong red-orange emission with no concentration quenching. The profile of PL spectra changes significantly at high Eu3+ content (x ≥ 0.80), which is due to the variation of preference for substitution of Eu3+. The luminescence due to the 5D0 → 7FJ (J = 1, 2) transitions at 77 K exhibits its own spectral features for different crystallographic site. It is found that Eu3+ ions occupy the centers of octahedral polyhedron and form Ci/C1 point group in Y(PO3)3.

  4. Can Vanadium Be Substituted into LiFePO[subscript 4]?

    SciTech Connect

    Omenya, Fredrick; Chernova, Natasha A.; Upreti, Shailesh; Zavalij, Peter Y.; Nam, Kyung-Wan; Yang, Xiao-Qing; Whittingham, M. Stanley

    2015-10-15

    Vanadium is shown to substitute for iron in the olivine LiFePO{sub 4} up to at least 10 mol %, when the synthesis is carried out at 550 C. In the solid solution LiFe{sub 1-3y/2}V{sub y}PO{sub 4}, the a and b lattice parameters and cell volume decrease with increasing vanadium content, while the c lattice parameter increases slightly. However, when the synthesis is performed at 650 C, a NASICON phase, Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}, is also formed, showing that solid solution is a function of the synthesis temperature. X-ray absorption near-edge structure indicates vanadium is in the 3+ oxidation state and in an octahedral environment. Magnetic studies reveal a shift of the antiferromagnetic ordering transition toward lower temperatures with increasing vanadium substitution, confirming solid solution formation. The addition of vanadium enhances the electrochemical performance of the materials especially at high current densities.

  5. Incorporation of Ln-Doped LaPO4 Nanocrystals as Luminescent Markers in Silica Nanoparticles.

    PubMed

    van Hest, Jacobine J H A; Blab, Gerhard A; Gerritsen, Hans C; Donega, Celso de Mello; Meijerink, Andries

    2016-12-01

    Lanthanide ions are promising for the labeling of silica nanoparticles with a specific luminescent fingerprint due to their sharp line emission at characteristic wavelengths. With the increasing use of silica nanoparticles in consumer products, it is important to label silica nanoparticles in order to trace the biodistribution, both in the environment and living organisms.In this work, we synthesized LaPO4 nanocrystals (NCs) with sizes ranging from 4 to 8 nm doped with europium or cerium and terbium. After silica growth using an inverse micelle method, monodisperse silica spheres were obtained with a single LaPO4 NC in the center. We demonstrate that the size of the silica spheres can be tuned in the 25-55 nm range by addition of small volumes of methanol during the silica growth reaction. Both the LaPO4 core and silica nanocrystal showed sharp line emission characteristic for europium and terbium providing unique optical labels in silica nanoparticles of variable sizes. PMID:27209405

  6. Radiopurity requirements for the SuperNEMO experiment and the BiPo detector

    NASA Astrophysics Data System (ADS)

    Eurin, Guillaume; SuperNEMO Collaboration

    2015-04-01

    The main goal of the SuperNEMO collaboration is to try to observe neutrinoless double-β decay. This would prove that the neutrino is a Majorana particle (ν = ν¯). Today the best lower limits on half-lives of this process are set around 1024 - 1026 years as obtained by the NEMO-3 experiment [1] (for the 2β isotope 100Mo) and other experiments. SuperNEMO is the next generation experiment based on the NEMO-3 tracker-calorimeter detection principle. The targeted contamination levels for the source foils are lower than can be measured through γ spectroscopy. A more sensitive detector has been constructed to measure low contaminations in 208Tl (around few μBq/kg) and 214Bi (few dozen μBq/kg) in thin materials: the BiPo detector. BiPo-3 has been fully operational at the Laboratorio Subterráneo de Canfranc (LSC) since January, 2013. The construction, performance and calibration of the BiPo-3 detector will be covered as well as the radiopurity requirements for SuperNEMO.

  7. Large-Area Balloon-Borne Polarized Gamma Ray Observer (PoGO)

    SciTech Connect

    Andersson, V.; Chen, P.; Kamae, T.; Madejski, G.; Mizuno, T.; Ng, J.; Tajima, H.; Thurston, T.; Bogaert, G.; Fukazawa, Y.; Saito, Y.; Takahashi, T.; Barbier, L.; Bloser, P.; Harding, A.; Hunter, S.; Krizmanic, J.; Mitchell, J.; Streitmatter, R.; Fernholz, R.; Groth, E.; /NASA, Goddard /Princeton U. /Royal Inst. Tech., Kista /Stockholm U. /Tokyo Inst. Tech. /Yamagata U.

    2005-06-30

    We are developing a new balloon-borne instrument (PoGO), to measure polarization of soft gamma rays (30-200 keV) using asymmetry in azimuth angle distribution of Compton scattering. PoGO is designed to detect 10% polarization in 100mCrab sources in a 6-8 hour observation and bring a new dimension to studies on gamma ray emission/transportation mechanism in pulsars, AGNs, black hole binaries, and neutron star surface. The concept is an adaptation to polarization measurements of well-type phoswich counter consisting of a fast plastic scintillator (the detection part), a slow plastic scintillator (the active collimator) and a BGO scintillator (the bottom anti-counter). PoGO consists of close-packed array of 217 hexagonal well-type phoswich counters and has a narrow field-of-view ({approx} 5 deg{sup 2}) to reduce possible source confusion. A prototype instrument has been tested in the polarized soft gamma-ray beams at Advanced Photon Source (ANL) and at Photon Factory (KEK). On the results, the polarization dependence of EGS4 has been validated and that of Geant4 has been corrected.

  8. Partnerships: The Key to Sustainability and Reach for E/PO

    NASA Astrophysics Data System (ADS)

    Eisenhamer, Bonnie; McCallister, D.; Ryer, H.

    2013-06-01

    The Space Telescope Science Institute (STScI) is the home institution for the E/PO activities of the Hubble and future James Webb space telescopes. Over time, STScI’s Office of Public Outreach has established the infrastructure needed for an E/PO program that reaches various audiences at the local, regional, and national levels. Partnerships are a critical element of this infrastructure, and sustainability of our E/PO program is ensured through our ongoing partnerships with organizations and institutions with staying power and reach. We have learned from past efforts that strategic partnerships can foster innovation, support diversity initiatives, and increase impact in a cost-effective way while providing target audiences with greater access to NASA SMD science and resources. Partnerships are utilized to field-test educational products and programs, disseminate materials and initiatives, and support professional development activities. Partners are selected based upon specific criteria such as potential for reach, the percentage of underrepresented educators and students served, complementary program goals, and willingness to collect and share evaluation data and results with us. This poster will highlight examples and benefits of strategic partnerships over time.

  9. ALTERNATIVE REMEDIATION TECHNOLOGY STUDY FOR GROUNDWATER TREATMENT AT 200-PO-1 OPERABLE UNIT AT HANFORD SITE

    SciTech Connect

    DADO MA

    2008-07-31

    This study focuses on the remediation methods and technologies applicable for use at 200-PO-I Groundwater Operable Unit (OU) at the Hanford Site. The 200-PO-I Groundwater au requires groundwater remediation because of the existence of contaminants of potential concern (COPC). A screening was conducted on alternative technologies and methods of remediation to determine which show the most potential for remediation of groundwater contaminants. The possible technologies were screened to determine which would be suggested for further study and which were not applicable for groundwater remediation. COPCs determined by the Hanford Site groundwater monitoring were grouped into categories based on properties linking them by remediation methods applicable to each COPC group. The screening considered the following criteria. (1) Determine if the suggested method or technology can be used for the specific contaminants found in groundwater and if the technology can be applied at the 200-PO-I Groundwater au, based on physical characteristics such as geology and depth to groundwater. (2) Evaluate screened technologies based on testing and development stages, effectiveness, implementability, cost, and time. This report documents the results of an intern research project conducted by Mathew Dado for Central Plateau Remediation in the Soil and Groundwater Remediation Project. The study was conducted under the technical supervision of Gloria Cummins and management supervision of Theresa Bergman and Becky Austin.

  10. Atomic structural and electrochemical impact of Fe substitution on nano porous LiMnPO4

    NASA Astrophysics Data System (ADS)

    Seo, Inseok; Senthilkumar, B.; Kim, Kwang-Ho; Kim, Jae-Kwang; Kim, Youngsik; Ahn, Jou-Hyeon

    2016-07-01

    The atomic structural and electrochemical properties of Fe substituted nano porous LiMn1-xFexPO4 (x = 0-0.8) composites are investigated and compared. X-ray scattering method is used for atomic structural investigation. Rietveld refinement shows that all Fe substituted composites have the same olivine structure (Pnma) with lithium occupying octahedral 4a sites, Fe2+ replacing Mn2+ at the octahedral 4c sites. The a, b, c parameters and cell volume decrease with the addition of Fe2+. When the nano porous LiMn1-xFexPO4 composites are evaluated as cathode materials in lithium cells at room temperature, x = 0.6, and 0.8 resulted in the best overall electrochemical performance, exhibiting stable cycling and high discharge capacities of 149 and 154 mA h g-1, respectively. The composites with above x = 0.4 show a fast lithium ions transfer with high electronic conductivity because Fe transition metal substitution reduce the partly occupation of Mn in the M1 (LiO6) sites and thereby Mn block the lithium ion diffusion pathway. We here firstly find the antisite defect in the high Mn content in porous LiMn1-xFexPO4 composites.

  11. The SDO Education and Outreach (E/PO) Program: Changing Perceptions One Program at a Time

    NASA Technical Reports Server (NTRS)

    Drobnes, E.; Littleton, A.; Pesnell, W. D.; Buhr, S.; Beck, K.; Durscher, R.; Hill, S.; McCaffrey, M.; McKenzie, D. E.; Myers, D.; Scherrer, D.; Wawro, M.; Wolt, A.

    2011-01-01

    The Solar Dynamics Observatory (SDO) Education and Public Outreach (E/PO) program began as a series of discrete efforts implemented by each of the instrument teams and has evolved into a well-rounded program with a full suite of national and international programs. The SDO E/PO team has put forth much effort in the past few years to increase our cohesiveness by adopting common goals and increasing the amount of overlap between our programs. In this paper, we outline the context and overall philosophy for our combined programs, present a brief overview of all SDO E/PO programs along with more detailed highlight of a few key programs, followed by a review of our results up to date. Concluding is a summary of the successes, failures, and lessons learned that future missions can use as a guide, while further incorporating their own content to enhance the public's knowledge and appreciation of NASA?s science and technology as well as its benefit to society.

  12. Optimized Operating Range for Large-Format LiFePO4/Graphite Batteries

    SciTech Connect

    Jiang, Jiuchun; Shi, Wei; Zheng, Jianming; Zuo, Pengjian; Xiao, Jie; Chen, Xilin; Xu, Wu; Zhang, Jiguang

    2014-06-01

    e investigated the long-term cycling performance of large format 20Ah LiFePO4/graphite batteries when they are cycled in various state-of-charge (SOC) ranges. It is found that batteries cycled in the medium SOC range (ca. 20~80% SOC) exhibit superior cycling stability than batteries cycled at both ends (0-20% or 80-100%) of the SOC even though the capcity utilized in the medium SOC range is three times as large as those cycled at both ends of the SOC. Several non-destructive techniques, including a voltage interruption approach, model-based parameter identification, electrode impedance spectra analysis, ΔQ/ΔV analysis, and entropy change test, were used to investigate the performance of LiFePO4/graphite batteries within different SOC ranges. The results reveal that batteries at the ends of SOC exhibit much higher polarization impedance than those at the medium SOC range. These results can be attributed to the significant structural change of cathode and anode materials as revealed by the large entropy change within these ranges. The direct correlation between the polarization impedance and the cycle life of the batteries provides an effective methodology for battery management systems to control and prolong the cycle life of LiFePO4/graphite and other batteries.

  13. AgPO2F2 and Ag9(PO2F2)14: the first Ag(i) and Ag(i)/Ag(ii) difluorophosphates with complex crystal structures.

    PubMed

    Malinowski, Przemysław J; Kurzydłowski, Dominik; Grochala, Wojciech

    2015-12-01

    The reaction of AgF2 with P2O3F4 yields a mixed valence Ag(I)/Ag(II) difluorophosphate salt with AgAg(PO2F2)14 stoichiometry - the first Ag(ii)-PO2F2 system known. This highly moisture sensitive brown solid is thermally stable up to 120 °C, which points at further feasible extension of the chemistry of Ag(ii)-PO2F2 systems. The crystal structure shows a very complex bonding pattern, comprising of polymeric Ag(PO2F2)14(4-) anions and two types of Ag(I) cations. One particular Ag(II) site present in the crystal structure of Ag9(PO2F2)14 is the first known example of square pyramidal penta-coordinated Ag(ii) in an oxo-ligand environment. Ag(i)PO2F2 - the product of the thermal decomposition of Ag9(PO2F2)14 - has also been characterized by thermal analysis, IR spectroscopy and X-ray powder diffraction. It has a complicated crystal structure as well, which consists of infinite 1D [Ag(I)O4/2] chains which are linked to more complex 3D structures via OPO bridges. The PO2F2(-) anions bind to cations in both compounds as bidentate oxo-ligands. The terminal F atoms tend to point inside the van der Waals cavities in the crystal structure of both compounds. All important structural details of both title compounds were corroborated by DFT calculations. PMID:26200921

  14. Single-crystalline LiFePO4 nanosheets for high-rate Li-ion batteries.

    PubMed

    Zhao, Yu; Peng, Lele; Liu, Borui; Yu, Guihua

    2014-05-14

    The lithiation/delithiation in LiFePO4 is highly anisotropic with lithium-ion diffusion being mainly confined to channels along the b-axis. Controlling the orientation of LiFePO4 crystals therefore plays an important role for efficient mass transport within this material. We report here the preparation of single crystalline LiFePO4 nanosheets with a large percentage of highly oriented {010} facets, which provide the highest pore density for lithium-ion insertion/extraction. The LiFePO4 nanosheets show a high specific capacity at low charge/discharge rates and retain significant capacities at high C-rates, which may benefit the development of lithium batteries with both favorable energy and power density.

  15. Emission red shift and unusual band narrowing of Mn2+ in NaCaPO4 phosphor.

    PubMed

    Shi, Liang; Huang, Yanlin; Seo, Hyo Jin

    2010-07-01

    Concentration dependence of Mn(2+) luminescence in NaCaPO(4)/Mn(2+) is investigated by structural analyses and optical and laser excitation spectroscopies in the temperature range 19-300 K. NaCaPO(4)/Mn(2+) forms solid solution over the Mn(2+) concentration range 1.0-22 mol %. We observe the red shift and unusual band narrowing of Mn(2+) emission by increasing Mn(2+) concentration in NaCaPO(4). The lifetime of Mn(2+) emission lengthens unexpectedly for higher Mn(2+) concentration. The results are discussed in relation with crystal structure, photon reabsorption, exchange interaction, and energy transfer and energy migration in NaCaPO(4)/Mn(2+).

  16. Direct and Repeated Clinical Measurements of pO2 for Enhancing Cancer Therapy and Other Applications.

    PubMed

    Swartz, Harold M; Williams, Benjamin B; Hou, Huagang; Khan, Nadeem; Jarvis, Lesley A; Chen, Eunice Y; Schaner, Philip E; Ali, Arif; Gallez, Bernard; Kuppusamy, Periannan; Flood, Ann B

    2016-01-01

    The first systematic multi-center study of the clinical use of EPR oximetry has begun, with funding as a PPG from the NCI. Using particulate oxygen sensitive EPR, materials in three complementary forms (India Ink, "OxyChips", and implantable resonators) the clinical value of the technique will be evaluated. The aims include using repeated measurement of tumor pO2 to monitor the effects of treatments on tumor pO2, to use the measurements to select suitable subjects for the type of treatment including the use of hyperoxic techniques, and to provide data that will enable existing clinical techniques which provide data relevant to tumor pO2 but which cannot directly measure it to be enhanced by determining circumstances where they can give dependable information about tumor pO2. PMID:27526130

  17. Structure determination, electronic and optical properties of rubidium holmium polyphosphate RbHo(PO3)4

    NASA Astrophysics Data System (ADS)

    Zhu, Jing; Chen, Hui; Wang, Yude; Guan, Hongtao; Xiao, Xuechun

    2012-12-01

    Structural, optical, and electronic properties of a new alkali metal-rare earth polyphosphate, RbHo(PO3)4, have been investigated by means of single-crystal X-ray diffraction, power X-ray diffraction, elemental analysis, and spectral measurement. RbHo(PO3)4 crystallizes in the monoclinic with space group P21/n and Z = 4. It is described as a three-dimensional (3D) architecture built up of PO4 double spiral chains and HoO8 polyhedra by corner-sharing. The 11-coordinated rubidium atoms are located in infinite tunnels. Additionally, in order to gain further insight into the relationship between property and structure of RbHo(PO3)4, theoretical calculation based on the density functional theory (DFT) was performed using the total-energy code CASTEP.

  18. Probing the failure mechanism of nanoscale LiFePO{sub 4} for Li-ion batteries

    SciTech Connect

    Gu, Meng; Yan, Pengfei; Wang, Chongmin; Shi, Wei; Zheng, Jianming; Zhang, Ji-guang

    2015-05-18

    LiFePO{sub 4} is a high power rate cathode material for lithium ion battery and shows remarkable capacity retention, featuring a 91% capacity retention after 3300 cycles. In this work, we use high-resolution transmission electron microscopy and electron energy loss spectroscopy to study the gradual capacity fading mechanism of LiFePO{sub 4} materials. We found that upon prolonged electrochemical cycling of the battery, the LiFePO{sub 4} cathode shows surface amorphization and loss of oxygen species, which directly contribute to the gradual capacity fading of the battery. The finding can guide the design and improvement of LiFePO{sub 4} cathode for high-energy and high-power rechargeable battery for electric transportation.

  19. Photoluminescence properties of Eu(3+)/ Sm(3+) activated CaZr4(PO4)6 phosphors.

    PubMed

    Nair, Govind B; Dhoble, S J

    2016-09-01

    Solid state reaction method was employed for the synthesis of a series of CaZr4(PO4)6: Eu(3+)/Sm(3+) phosphors. The red-emitting CaZr4(PO4)6:Eu(3+) phosphors can be efficiently excited at 396 nm and thereby, exhibit a strong red luminescence predominantly corresponding to the electric dipole transition at 615 nm. Under 405 nm excitation, CaZr4(PO4)6:Sm(3+) phosphors display orange emission with color temperatures approximately around 2200 K. The acquired results reveal that CaZr4(PO4)6: RE(3+) (RE = Eu, Sm) phosphors could be potential candidates for red and orange emitting phosphor, respectively, for UV/blue-pump LEDs. PMID:27411525

  20. Structure of Zr 2(WO 4)(PO 4) 2 from Powder X-Ray Data: Cation Ordering with No Superstructure

    NASA Astrophysics Data System (ADS)

    Evans, J. S. O.; Mary, T. A.; Sleight, A. W.

    1995-11-01

    Department of Chemistry and Center for Advanced Materials Research, Oregon State University, Corvallis, Oregon The ab initio structure determination of Zr2(WO4)(PO4)2 from room temperature powder X-ray diffraction data is reported. This compound crystallizes in the orthorhombic space group Pnca with a = 9.35451(9), b = 12.31831(9), and c = 9.16711(8) Å. The structure is based on ZrO6 octahedra sharing corners with WO4 and PO4 tetrahedra. Although Zr2(WO4)(PO4)2 is isostructural with Fe2(MoO4)3 and its WO4 and PO4 tetrahedra are well ordered, no superstructure or change in space group is required to account for this ordering.

  1. Determination of Critical Point of pO2 Level in the Production of Lactic Acid by Lactobacillus rhamnosus

    NASA Astrophysics Data System (ADS)

    Mel, Maizirwan; Karim, Mohamed Ismail Abdul; Salleh, Mohamad Ramlan Mohamed; Abdullah, Rohane

    The study was conducted to determine the critical point of pO2 level in the production of lactic acid by Lactobacillus rhamnosus. The fermentation process was successfully carried out in laboratory scale fermenter/bioreactor using different pO2 level (the main parameter that significantly affects the growth of L. rhamnosus and lactic acid production) together with two other parameters; the agitation rate and pH. From the result, it was observed that the best production of lactic acid with the concentration of 16.85 g L-1 or 1.68% production yield has been obtained at the operating parameters of 5% pO2 level, agitation speed of 100 rpm and sample pH 6. The critical point of pO2 was found to be between 5 and 10%.

  2. Photoluminescence properties of Eu(3+)/ Sm(3+) activated CaZr4(PO4)6 phosphors.

    PubMed

    Nair, Govind B; Dhoble, S J

    2016-09-01

    Solid state reaction method was employed for the synthesis of a series of CaZr4(PO4)6: Eu(3+)/Sm(3+) phosphors. The red-emitting CaZr4(PO4)6:Eu(3+) phosphors can be efficiently excited at 396 nm and thereby, exhibit a strong red luminescence predominantly corresponding to the electric dipole transition at 615 nm. Under 405 nm excitation, CaZr4(PO4)6:Sm(3+) phosphors display orange emission with color temperatures approximately around 2200 K. The acquired results reveal that CaZr4(PO4)6: RE(3+) (RE = Eu, Sm) phosphors could be potential candidates for red and orange emitting phosphor, respectively, for UV/blue-pump LEDs.

  3. (210)Po in drinking water, its potential health effects, and inadequacy of the gross alpha activity MCL.

    PubMed

    Seiler, Ralph

    2016-10-15

    Polonium-210 ((210)Po) is a naturally-occurring, carcinogenic member of the (238)U decay series and the granddaughter of (210)Pb. It has a half life of 138.4days and is rarely found in drinking water at levels exceeding 5mBq/L because it strongly binds to aquifer sediment. When the current US Maximum Contaminant Level (MCL) covering (210)Po was promulgated in December 2000, very little was known about its occurrence and the processes responsible for mobilizing it. More is now known about the processes that mobilize (210)Po from sediments and a review of recent occurrence data show that it may not be as rare in the US as the US Environmental Protection Agency (USEPA) thought in 2000. Worldwide, only about 2200 analyses for (210)Po in drinking water were identified, with activities exceeding 500mBq/L being found only in Finland, India, Sweden, and the US. The median of 400 (210)Po analyses from the US is 4.75mBq/L and >10% of the samples exceed 500mBq/L. Current compliance-monitoring regulations in the US essentially guarantee that (210)Po contamination will not be detected except in very contaminated wells. Major problems with the US Gross Alpha Activity MCL include the volatility of (210)Po and extended holding times and sample-compositing methods that can allow the majority of (210)Po in a sample bottle to decay before analysis. In light of new information, the radionuclide rule should be changed and direct measurements of (210)Po should be made in all public-water supply wells to rule out its presence. Much of the important biological and toxicological research on (210)Po is more than four decades old and new laboratory research using modern tools is needed. Biological and epidemiological investigations of known contaminated areas are needed to assess the effect (210)Po exposure is having on animals and humans consuming the water. PMID:27369089

  4. Low temperature phase transition and crystal structure of CsMgPO{sub 4}

    SciTech Connect

    Orlova, Maria; Khainakov, Sergey; Michailov, Dmitriy; Perfler, Lukas; Langes, Christoph; Kahlenberg, Volker; Orlova, Albina

    2015-01-15

    CsMgPO{sub 4} doped with radioisotopes is a promising compound for usage as a radioactive medical source. However, a low temperature phase transition at temperatures close to ambient conditions (∼−40 °C) was observed. Information about such kind of structural changes is important in order to understand whether it can cause any problem for medical use of this compound. The phase transition has been investigated in detail using synchrotron powder diffraction, Raman spectroscopy and DFT calculations. The structure undergoes a transformation from an orthorhombic modification, space group Pnma (RT phase) to a monoclinic polymorph, space group P2{sub 1}/n (LT phase). New LT modification adopts similar to RT but slightly distorted unit cell: a=9.58199(2) Å, b=8.95501(1) Å, c=5.50344(2) Å, β=90.68583(1)°, V=472.198(3) Å{sup 3}. CsMgPO{sub 4} belongs to the group of framework compounds and is made up of strictly alternating MgO{sub 4}- and PO{sub 4}-tetrahedra sharing vertices. The cesium counter cations are located in the resulting channel-like cavities. Upon the transformation a combined tilting of the tetrahedra is observed. A comparison with other phase transitions in ABW-type framework compounds is given. - Graphical abstract: Structural behavior of β-tridymite-type phosphate CsMgPO{sub 4}, considered as potential chemical form for radioactive Cs-source has been studied at near ambient temperatures. A phase transition at (∼−40 °C) has been found and investigated. It has been established that the known orthorhombic RT modification, space group Pnma, adopts a monoclinic cell with space group P2{sub 1}/n at low temperatures. In this paper, we present results of structural analysis of changes accompanying this phase transition and discuss its possible impact on the application properties. - Highlights: • β-Tridymite type phosphate CsMgPO{sub 4} undergoes so called translationengleiche phase transition of index 2 at −40 °C. • The structure

  5. Biokinetics of ²¹⁰Po in rats: excretion via urine and faeces and retention in tissues and organs.

    PubMed

    Li, Chunsheng; Sadi, Baki; Wyatt, Heather; Bugden, Michelle; Priest, Nick; Wilkinson, Diana; Kramer, Gary

    2011-06-01

    Daily excretions of ²¹⁰Po from rats via urine and faeces following i.v. administration of polonium citrate, from Day 2 to Day 5, were reported, together with retentions in tissues and organs on Day 5. Emphasis is given to the methods of measurement and data quality rather than to the discussion of the observations. The authors aim to contribute data for developing or refining the biokinetic model for ²¹⁰Po metabolism.

  6. Evaluation of plating conditions for the recovery of ²¹⁰Po on a Ag planchet.

    PubMed

    Lee, Hyun Mi; Hong, Gi Hoon; Baskaran, Mark; Kim, Suk Hyun; Kim, Young Ill

    2014-08-01

    The polonium-210 in the sea and its radiological consequences have been widely studied. Current processes for (210)Po recovery from seawater vary significantly. We compared selected processes to determine optimal conditions for recovery in modestly equipped laboratories. Plating (210)Po onto a Ag planchet with constant stirring for 15 h at room temperature after preconcentration from seawater samples with Mn was preferred, achieving more than 96% recovery with 3% or less precision. Possible contaminants were masked only by ascorbic acid treatment.

  7. Morphology-controlled synthesis of Ag{sub 3}PO{sub 4} nano/microcrystals and their antibacterial properties

    SciTech Connect

    Wu, Aiping; Tian, Chungui; Chang, Wei; Hong, Yu; Zhang, Qi; Qu, Yang; Fu, Honggang

    2013-09-01

    Graphical abstract: The Ag{sub 3}PO{sub 4} with rhombic dodecahedral, spherical and small size particles were controllable fabricated just by changing the types of the solvent. The materials possess good antibacterial properties toward different kinds of bacteria. - Highlights: • The Ag{sub 3}PO{sub 4} with three morphologies were controllable fabricated. • The Ag{sub 3}PO{sub 4} as-prepared possess obvious antibacterial properties in the dark. • The antibacterial ability of Ag{sub 3}PO{sub 4} could be greatly improved under the visible light irradiation. - Abstract: We reported the controllable fabrication of Ag{sub 3}PO{sub 4} nano/microcrystals through a simple solution-based precipitation reaction. The samples were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy and infrared spectroscopy. The results indicated that the Ag{sub 3}PO{sub 4} crystals with three different morphology, including the rhombic dodecahedron of 500 nm, the sphere of 100 nm and the particles with small-size of 20 nm, could be obtained in the solvents of water, ethylene glycol (EG) and dimethyl sulfoxide (DMSO). The antibacterial assay showed that all samples possess obvious antibacterial properties. In addition, the Ag{sub 3}PO{sub 4} with small size of 20 nm showed better activity due to their high specific surface areas. Notably, we have found that the antibacterial ability of Ag{sub 3}PO{sub 4} could be greatly improved under the visible light irradiation, which are superior to that in the dark and commercial streptomycin.

  8. Customer Support Operations In Support Of The NASA/JPL Physical Oceanography Distributed Active Archive Center (PO.DAAC)

    NASA Astrophysics Data System (ADS)

    Heinz, S. L.; Chen, Y. M.

    2004-12-01

    PO.DAAC is responsible for the ingest, archive and distribution of data relevant to the physical state of the ocean. The PO.DAAC provides a level of service for customer support for core Earth Observing System Data Information System (EOSDIS) missions such as TOPEX/POSEIDON, Jason, SeaWinds on QuikSCAT, SeaWinds on ADEOS-II, NOAA AVHRR and MODIS. PO.DAAC's level of support has broadened recently to include missions outside of the EOSDIS including, WindSat, GHRSST, Naval Oceanographic, Monterey Bay Aquarium, AirSAR and GOES. Customer support operations is managed and conducted in partnership between Raytheon ITSS and JPL and includes a full complement of services to accommodate the various PO.DAAC and Earth Observing System user communities. Customer support activities are ubiquitous to service industries from banking to shopping and this presentation will detail how two operational applications have been adopted for use in Earth Science data communities. Customer Response Management Operations System Integrated system that combines PO.DAAC's communications channels including web, email, phone and personal interactions into one intelligent knowledge base. The knowledge is shared with customers and the entire team to deliver consistent and timely information. The system allows 24 x 7 customer support service via extensive on-line searchable knowledge base. PO.DAAC has customized the system to fully integrate with PO.DAAC's existing legacy database and order tracking system. Website Communication Channel The newly redesigned PO.DAAC website (http://podaac.jpl.nasa.gov) is the central gateway to all of the Data, Tools and Services offered at the data center. The consistent look and feel was developed to enhance the ease of searching and ordering earth science data in particular. Data is accessible within a few clicks using the improved dynamic data catalog interface. New data products and information are delivered quickly to customers via the dynamic system and

  9. Oscillation in the Kmno 4NH 2CH 2COOHH 3PO 4 Cstr system

    NASA Astrophysics Data System (ADS)

    Li, Hexing; Huang, Xiaojun; Deng, Jingfa

    1996-08-01

    A novel chemical oscillating reaction in the KMnO 4NH 2CH 2COOHH 3PO 4 CSTR system in the presence and absence of Ag + has been described. The reaction kinetics in a closed Mn0 4-NH 2CH 2COOHH 3PO 4 system has been analyzed and a possible mechanism has been proposed. The catalytic effect of Ag + in the above reaction has also been studied.

  10. Multi-spin-state at a Li3PO4/LiCoO2 (104) interface.

    PubMed

    Sumita, Masato; Ohno, Takahisa

    2016-02-14

    We have found the disproportion between the intermediate spin (IS) and low spin (LS) configurations of Co atoms at a Li3PO4/LiCoO2 (104) interface through density functional molecular dynamics (DF-MD). The manifold of the spin state at the interface, however, does not affect the band alignment between the Li3PO4 and LiCoO2 regions. PMID:26812388

  11. Mechanism of reduction in alveolar-arterial PO2 difference by helium breathing in the exercising horse.

    PubMed

    Erickson, B K; Seaman, J; Kubo, K; Hiraga, A; Kai, M; Yamaya, Y; Wagner, P D

    1994-06-01

    Previous work has shown that replacing N2 in air with He at the same inspired O2 fraction reduces the exercise-induced alveolar-arterial PO2 difference (AaPO2) in horses but has provided no mechanism explaining this effect. We sought to distinguish among possible causes by using the multiple inert gas elimination technique. Six horses were studied on a high-speed treadmill while they breathed either ambient air or normoxic He-O2. O2 uptake reached 138.0 ml.min-1.kg-1 and was not affected by He-O2. Temperature-corrected arterial PO2 was 76.7 Torr (air) and 86.9 Torr (He-O2) (P < 0.01). Corresponding AaPO2 was 22.3 and 15.9 Torr, respectively (P < 0.01). Mean AaPO2 predicted from ventilation-perfusion inequality did not change with He-O2 (12.7 Torr with air and 11.9 Torr with He-O2). Mean arterial PCO2 was 50.1 Torr with air and 44.1 Torr with He-O2 (P < 0.01); minute ventilation and tidal volume were correspondingly higher by 140 l/min and 1.0 liter, respectively, with He-O2. Pulmonary O2 diffusing capacity, cardiac output, and all ventilation-perfusion dispersion indexes did not change with He-O2. Intrapulmonary shunt was insignificant. Higher ventilation with He-O2 explained only approximately 4 Torr of the 10-Torr rise observed in arterial PO2. The remainder (and the corresponding fall in AaPO2) was due to more complete diffusion equilibration as a consequence of the higher minute ventilation and thus alveolar PO2, which reduced the average slope of the O2 dissociation curve, thereby increasing the ratio of diffusive to perfusive conductance.

  12. (7)Be, (210)Pb, and (210)Po in the surface air from the Arctic to Antarctica.

    PubMed

    Persson, Bertil R R; Holm, Elis

    2014-12-01

    In the present study we have investigated the activity concentrations of (210)Pb, (210)Po as well as (7)Be in surface air of the North and South Atlantic (1988-1989), the Arctic Ocean (1991), and along the coastline of Siberia (1994) during succeeding expeditions in the Swedish Polar Research program. During the cruises in the Arctic Ocean during 1991-07-28 to 1991-10-04 the average air concentrations of (7)Be was 0.6 ± 0.4 mBq/m(3), (210)Pb 40 ± 4 μBq/m(3) and (210)Po-38 ± 10 μBq/m(3). During the Swedish-Russian Tundra Ecology-94 expedition along the Siberian coastline the average air concentrations of (7)Be and (210)Pb measured during May-July were 11 ± 3, and 2.4 ± 0.4 mBq/m(3), and during July-September they were 7.2 ± 2 and 2.7 ± 1.1 mBq/m(3) respectively. The results from measurements of the activity concentration of (210)Pb in the air over the Arctic Ocean vary between 75 and 176 μBq/m(3). In the air close to land masses, however, the activity concentration of (210)Pb in the air increases to 269-2712 μBq/m(3). The activity concentration of (7)Be in the South Atlantic during the cruise down to Antarctica varied between 1.3 and 1.7 with an average of 1.5 ± 0.8 mBq/m(3). The activity concentration of (210)Pb in the South Atlantic down to Antarctica varied between 6 and 14 μBq/m(3). At the Equator the activity concentration recorded in November 1988 was 630 μBq/m(3) and in April 1989 it was 260 μBq/m(3). The average activity concentration of (210)Pb during the route Gothenburg-Montevideo in 1988 was 290 and on the return Montevideo-Gothenburg it was 230 μBq/m(3). The activity concentration of (210)Po in the South Atlantic down to Antarctica varied between 15 and 58 μBq/m(3). At the Equator the activity concentration in November 1988 was 170 and in April 1989 it was 70 μBq/m(3). The average activity concentration of (210)Po during the route Gothenburg-Montevideo in 1988 was 63 and on the return Montevideo

  13. (7)Be, (210)Pb, and (210)Po in the surface air from the Arctic to Antarctica.

    PubMed

    Persson, Bertil R R; Holm, Elis

    2014-12-01

    In the present study we have investigated the activity concentrations of (210)Pb, (210)Po as well as (7)Be in surface air of the North and South Atlantic (1988-1989), the Arctic Ocean (1991), and along the coastline of Siberia (1994) during succeeding expeditions in the Swedish Polar Research program. During the cruises in the Arctic Ocean during 1991-07-28 to 1991-10-04 the average air concentrations of (7)Be was 0.6 ± 0.4 mBq/m(3), (210)Pb 40 ± 4 μBq/m(3) and (210)Po-38 ± 10 μBq/m(3). During the Swedish-Russian Tundra Ecology-94 expedition along the Siberian coastline the average air concentrations of (7)Be and (210)Pb measured during May-July were 11 ± 3, and 2.4 ± 0.4 mBq/m(3), and during July-September they were 7.2 ± 2 and 2.7 ± 1.1 mBq/m(3) respectively. The results from measurements of the activity concentration of (210)Pb in the air over the Arctic Ocean vary between 75 and 176 μBq/m(3). In the air close to land masses, however, the activity concentration of (210)Pb in the air increases to 269-2712 μBq/m(3). The activity concentration of (7)Be in the South Atlantic during the cruise down to Antarctica varied between 1.3 and 1.7 with an average of 1.5 ± 0.8 mBq/m(3). The activity concentration of (210)Pb in the South Atlantic down to Antarctica varied between 6 and 14 μBq/m(3). At the Equator the activity concentration recorded in November 1988 was 630 μBq/m(3) and in April 1989 it was 260 μBq/m(3). The average activity concentration of (210)Pb during the route Gothenburg-Montevideo in 1988 was 290 and on the return Montevideo-Gothenburg it was 230 μBq/m(3). The activity concentration of (210)Po in the South Atlantic down to Antarctica varied between 15 and 58 μBq/m(3). At the Equator the activity concentration in November 1988 was 170 and in April 1989 it was 70 μBq/m(3). The average activity concentration of (210)Po during the route Gothenburg-Montevideo in 1988 was 63 and on the return Montevideo

  14. Vibrational spectroscopy of the phosphate mineral kovdorskite - Mg2PO4(OH)ṡ3H2O

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    The mineral kovdorskite Mg2PO4(OH)ṡ3H2O was studied by electron microscopy, thermal analysis and vibrational spectroscopy. A comparison of the vibrational spectroscopy of kovdorskite is made with other magnesium bearing phosphate minerals and compounds. Electron probe analysis proves the mineral is very pure. The Raman spectrum is characterized by a band at 965 cm-1 attributed to the PO43- ν1 symmetric stretching mode. Raman bands at 1057 and 1089 cm-1 are attributed to the PO43- ν3 antisymmetric stretching modes. Raman bands at 412, 454 and 485 cm-1 are assigned to the PO43- ν2 bending modes. Raman bands at 536, 546 and 574 cm-1 are assigned to the PO43- ν4 bending modes. The Raman spectrum in the OH stretching region is dominated by a very sharp intense band at 3681 cm-1 assigned to the stretching vibration of OH units. Infrared bands observed at 2762, 2977, 3204, 3275 and 3394 cm-1 are attributed to water stretching bands. Vibrational spectroscopy shows that no carbonate bands are observed in the spectra; thus confirming the formula of the mineral as Mg2PO4(OH)ṡ3H2O.

  15. Carbon-coated LiFePO4-porous carbon composites as cathode materials for lithium ion batteries.

    PubMed

    Ni, Haifang; Liu, Jinkun; Fan, Li-Zhen

    2013-03-01

    This work introduces a facile strategy for the synthesis of carbon-coated LiFePO(4)-porous carbon (C-LiFePO(4)-PC) composites as a cathode material for lithium ion batteries. The LiFePO(4) particles obtained are about 200 nm in size and homogeneously dispersed in porous carbon matrix. These particles are further coated with the carbon layers pyrolyzed from sucrose. The C-LiFePO(4)-PC composites display a high initial discharge capacity of 152.3 mA h g(-1) at 0.1 C, good cycling stability, as well as excellent rate capability (112 mA h g(-1) at 5 C). The likely contributing factors to the excellent electrochemical performance of the C-LiFePO(4)-PC composites could be related to the combined effects of enhancement of conductivity by the porous carbon matrix and the carbon coating layers. It is believed that further carbon coating is a facile and effective way to improve the electrochemical performance of LiFePO(4)-PC.

  16. 210Po and 210Pb Activity Concentrations in Cigarettes Produced in Vietnam and Their Estimated Dose Contribution Due to Smoking

    NASA Astrophysics Data System (ADS)

    Tran, Thuy-Ngan N.; Le, Cong-Hao; Chau, Van-Tao

    Smoking cigarettes contributes significantly to the increase of radiation in human body because 210Po and 210Pb exist relatively high in tobacco leaves. Therefore, these two radioisotopes in eighteen of the most frequently sold cigarette brands produced in Vietnam were examined in this study. 210Po was determined by alpha spectroscopy using a passivated implanted planar silicon (PIPS) detector after a procedure including radiochemical separation and spontaneous deposition of polonium on a copper disc (the deposition efficiency of 210Po on a copper disc was approximately 94%). Sequentially, 210Pb was determined through the ingrowth of 210Po after storing the sample solutions for approximately six months. The activity concentrations of 210Po in cigarettes ranged from 13.8 to 82.6 mBq/cigarette (the mean value was 26.4 mBq/cigarette) and the activity concentrations of 210Pb in cigarettes ranged from 13.9 to 78.8 mBq/cigarette (the mean value was 25.8 mBq/cigarette). The annual committed effective dose for smokers who smoke one pack per day was also estimated to be 295.4 µSv/year (223.0 µSv/year and 72.4 µSv/year from 210Po and 210Pb, respectively). These indicated that smoking increased the risk of developing lung cancer was approximately 60 times greater for smokers than for non-smokers.

  17. Polonium (210Po) and lead (210Pb) in marine organisms and their transfer in marine food chains.

    PubMed

    Carvalho, Fernando P

    2011-05-01

    The determination of (210)Po and (210)Pb was performed in marine organisms from the seashore to abyssal depths, encompassing a plethora of species from the microscopic plankton to the sperm whale. Concentrations of those radionuclides ranged from low values of about 5 × 10(-1) Bq kg(-1) (wet wt.) in jellyfish, to very high values of about of 3 × 10(4) Bq kg(-1) (wet wt.) in the gut walls of sardines, with a common pattern of (210)Po > (210)Pb.These radionuclides are primarily absorbed from water and concentrated by phyto- and microzooplankton, and then are transferred to the next trophic level along marine food chains. Investigation in epipelagic, mesopelagic, bathypelagic and abyssobenthic organisms revealed that (210)Po is transferred in the marine food webs with transfer factors ranging from 0.1 to 0.7, and numerically similar to those of the energy transfer in the marine food chains. As (210)Po preferentially binds to amino acids and proteins, its transfer in food chains likely traces protein transfer and, thus, (210)Po transfer factors are similar to ecotrophic coefficients. (210)Pb is transferred less efficiently in marine food chains and this contributes to increased (210)Po:(210)Pb activity ratios in some trophic levels.

  18. Cross section systematics for the lightest Bi and Po nuclei produced in complete fusion reactions with heavy ions

    SciTech Connect

    Andreyev, A.N.; Ackermann, D.; Muenzenberg, G.; Antalic, S.; Saro, S.; Streicher, B.; Darby, I.G.; Page, R.D.; Wiseman, D.R.; Franchoo, S.; Hessberger, F.P.; Kuusiniemi, P.; Lommel, B.; Kindler, B.; Mann, R.; Sulignano, B.; Hofmann, S.; Huyse, M.; Vel, K. van de; Duppen, P. van

    2005-07-01

    The production of the very neutron-deficient nuclides {sup 184-192}Bi and {sup 186-192}Po in the vicinity of the neutron midshell at N = 104 has been studied by using heavy-ion-induced complete fusion reactions in a series of experiments at the velocity filter SHIP. The cross sections for the xn and pxn evaporation channels of the {sup 46}Ti+{sup 144}Sm{yields}{sup 190}Po*,{sup 98}Mo+{sup 92}Mo{yields}{sup 190}Po*,{sup 50,52}Cr+{sup 142}Nd{yields}{sup 192,194}Po*, and {sup 94,95}Mo+{sup 93}Nb{yields}{sup 187,188}Bi* reactions were measured. The results obtained, together with the previously known cross section data for the heavier Bi and Po nuclides, are compared with the results of statistical model calculations carried out with the HIVAP code. It is shown that a satisfactory description of the experimental data requires a significant (up to 35%) reduction of the theoretical fission barriers. The optimal reactions for production of the lightest Bi and Po isotopes are discussed.

  19. Assessment of soil contamination by (210)Po and (210)Pb around heavy oil and natural gas fired power plants.

    PubMed

    Al-Masri, M S; Haddad, Kh; Doubal, A W; Awad, I; Al-Khatib, Y

    2014-06-01

    Soil contamination by (210)Pb and (210)Po around heavy oil and natural gas power plants has been investigated; fly and bottom ash containing enhanced levels of (210)Pb and (210)Po were found to be the main source of surface soil contamination. The results showed that (210)Pb and (210)Po in fly-ash (economizer, superheater) is highly enriched with (210)Pb and (210)Po, while bottom-ash (boiler) is depleted. The highest (210)Pb and (210)Po activity concentrations were found to be in economizer ash, whereas the lowest activity concentration was in the recirculator ash. On the other hand, (210)Pb and (210)Po activity concentrations in soil samples were found to be higher inside the plant site area than those samples collected from surrounding areas. The highest levels were found in the vicinity of Mhardeh and Tishreen power plants; both plants are operated by heavy oil and natural fuels, while the lowest values were found to be in those samples collected from Nasrieh power plant, which is only operated by one type of fuel, viz. natural gas. In addition, the levels of surface soil contamination have decreased as the distance from the power plant site center increased.

  20. Vibrational spectroscopy of the phosphate mineral kovdorskite-Mg2PO4(OH)·3H2O.

    PubMed

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

    2013-10-01

    The mineral kovdorskite Mg2PO4(OH)·3H2O was studied by electron microscopy, thermal analysis and vibrational spectroscopy. A comparison of the vibrational spectroscopy of kovdorskite is made with other magnesium bearing phosphate minerals and compounds. Electron probe analysis proves the mineral is very pure. The Raman spectrum is characterized by a band at 965 cm(-1) attributed to the PO4(3-) ν1 symmetric stretching mode. Raman bands at 1057 and 1089 cm(-1) are attributed to the PO4(3-) ν3 antisymmetric stretching modes. Raman bands at 412, 454 and 485 cm(-1) are assigned to the PO4(3-) ν2 bending modes. Raman bands at 536, 546 and 574 cm(-1) are assigned to the PO4(3-) ν4 bending modes. The Raman spectrum in the OH stretching region is dominated by a very sharp intense band at 3681 cm(-1) assigned to the stretching vibration of OH units. Infrared bands observed at 2762, 2977, 3204, 3275 and 3394 cm(-1) are attributed to water stretching bands. Vibrational spectroscopy shows that no carbonate bands are observed in the spectra; thus confirming the formula of the mineral as Mg2PO4(OH)·3H2O.

  1. Assessment of soil contamination by (210)Po and (210)Pb around heavy oil and natural gas fired power plants.

    PubMed

    Al-Masri, M S; Haddad, Kh; Doubal, A W; Awad, I; Al-Khatib, Y

    2014-06-01

    Soil contamination by (210)Pb and (210)Po around heavy oil and natural gas power plants has been investigated; fly and bottom ash containing enhanced levels of (210)Pb and (210)Po were found to be the main source of surface soil contamination. The results showed that (210)Pb and (210)Po in fly-ash (economizer, superheater) is highly enriched with (210)Pb and (210)Po, while bottom-ash (boiler) is depleted. The highest (210)Pb and (210)Po activity concentrations were found to be in economizer ash, whereas the lowest activity concentration was in the recirculator ash. On the other hand, (210)Pb and (210)Po activity concentrations in soil samples were found to be higher inside the plant site area than those samples collected from surrounding areas. The highest levels were found in the vicinity of Mhardeh and Tishreen power plants; both plants are operated by heavy oil and natural fuels, while the lowest values were found to be in those samples collected from Nasrieh power plant, which is only operated by one type of fuel, viz. natural gas. In addition, the levels of surface soil contamination have decreased as the distance from the power plant site center increased. PMID:24602817

  2. Cloning, expression, and characterization of a milk-clotting aspartic protease gene (Po-Asp) from Pleurotus ostreatus.

    PubMed

    Yin, Chaomin; Zheng, Liesheng; Chen, Liguo; Tan, Qi; Shang, Xiaodong; Ma, Aimin

    2014-02-01

    An aspartic protease gene from Pleurotus ostreatus (Po-Asp) had been cloned based on the 3' portion of cDNA in our previous work. The Po-Asp cDNA contained 1,324 nucleotides with an open reading frame (ORF) of 1,212 bp encoding 403 amino acid residues. The putative amino acid sequence included a signal peptide, an activation peptide, two most possible N-glycosylation sites and two conserved catalytic active site. The mature polypeptide with 327 amino acid residues had a calculated molecular mass of 35.3 kDa and a theoretical isoelectric point of 4.57. Basic Local Alignment Search Tool analysis showed 68-80 % amino acid sequence identical to other basidiomycetous aspartic proteases. Sequence comparison and evolutionary analysis revealed that Po-Asp is a member of fungal aspartic protease family. The DNA sequence of Po-Asp is 1,525 bp in length without untranslated region, consisting of seven exons and six introns. The Po-Asp cDNA without signal sequence was expressed in Pichia pastoris and sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated the molecular mass of recombinant Po-Asp was about 43 kDa. The crude recombinant aspartic protease had milk-clotting activity.

  3. Theoretical study of the structure and analytic potential energy function for the ground state of the PO2 molecule

    NASA Astrophysics Data System (ADS)

    Zeng, Hui; Zhao, Jun

    2012-07-01

    In this paper, the energy, equilibrium geometry, and harmonic frequency of the ground electronic state of PO2 are computed using the B3LYP, B3P86, CCSD(T), and QCISD(T) methods in conjunction with the 6-311++G(3df, 3pd) and cc-pVTZ basis sets. A comparison between the computational results and the experimental values indicates that the B3P86/6-311++G(3df, 3pd) method can give better energy calculation results for the PO2 molecule. It is shown that the ground state of the PO2 molecule has C2ν symmetry and its ground electronic state is X2A1. The equilibrium parameters of the structure are RP-O = 0.1465 nm, ∠OPO = 134.96°, and the dissociation energy is Ed = 19.218 eV. The bent vibrational frequency ν1 = 386 cm-1, symmetric stretching frequency ν2 = 1095 cm-1, and asymmetric stretching frequency ν3 = 1333 cm-1 are obtained. On the basis of atomic and molecular reaction statics, a reasonable dissociation limit for the ground state of the PO2 molecule is determined. Then the analytic potential energy function of the PO2 molecule is derived using many-body expansion theory. The potential curves correctly reproduce the configurations and the dissociation energy for the PO2 molecule.

  4. 'Scarlett Spur Red Delicious' apple volatile production accompanying physiological disorder development during low pO2 controlled atmosphere storage.

    PubMed

    Lumpkin, Christie; Fellman, John K; Rudell, David R; Mattheis, James

    2014-02-19

    Apple (Malus domestica Borkh.) fruit volatile production is regulated by a variety of factors including low oxygen storage conditions. This study examined the impact of low pO2 controlled atmospheres on 'Scarlett Spur Red Delicious' apple volatile production and disorder development. Accumulation of apple volatile compounds was characterized during long-term cold storage at 0.5 °C in air or low pO2 (0.3, 0.8, or 1.5 kPa) with 1 kPa CO2. Volatile accumulation differed quantitatively with pO2 as acetaldehyde, ethanol, and ethyl ester accumulation increased with decreased pO2 during the first weeks in storage. Differences in volatile accumulation among atmospheres were evident through 6 months. The rate of ethanol accumulation increased with decreased pO2 and could potentially be used to monitor low O2 stress. Incidence of low oxygen disorders after 9 months was highest in fruit held at the lowest pO2. The sesquiterpene α-farnesene was not detected throughout the storage period.

  5. Synthesis and Electrochemical Performance of the Na3V2(PO4)3 Cathode for Sodium-Ion Batteries

    NASA Astrophysics Data System (ADS)

    Van Nghia, Nguyen; Jafian, Samuel; Hung, I.-Ming

    2016-05-01

    Rhombohedral Na3V2(PO4)3 with a Na+ superionic conductor structure was synthesized using a solid-state reaction method. Citric acid was used as a carbon resource for carbon-thermal reduction reaction to reduce the oxidation state of vanadium. The shape of Na3V2(PO4)3 particles is irregular and its average diameter is in the range 30-50 nm. The Na3V2(PO4)3 exhibits a superior cycling ability and rate capability. The discharge capacity retains 74.3% of the discharge capacity of its first cycle with coulombic efficiency of 99.3% after 100 cycles. The discharge capacity of Na3V2(PO4)3 at 10 C is 48.87 mAh g-1, which is 58.4% of the cell cycled at 0.1 C. Furthermore, the structure of Na3V2(PO4)3 is stable for a considerable amount of Na+ ions (2 mol of Na+ ions) insertion and extraction with only 0.42% difference of unit-cell volume between fully charged and discharged states. Na3V2(PO4)3 is a potential cathode material for sodium-ion battery applications.

  6. Radioactivity of cigarettes and the importance of (210)Po and thorium isotopes for radiation dose assessment due to smoking.

    PubMed

    Kubalek, Davor; Serša, Gregor; Štrok, Marko; Benedik, Ljudmila; Jeran, Zvonka

    2016-05-01

    Tobacco and tobacco smoke are very complex mixtures. In addition to various chemical and organic compounds they also contain natural radioactive elements (radionuclides). In this work, the natural radionuclide activity concentrations ((234)U, (238)U, (228)Th, (230)Th, (232)Th, (226)Ra, (210)Pb and (210)Po) of nine different cigarette samples available on the Slovenian market are reported. In addition to (210)Po, the transfer of thorium isotopes from a cigarette to a smoker's body and lungs have been determined for the first time. Cigarette smoke and exhaled air from smokers' lungs were collected from volunteer smokers (C-4 brand) to determinate what quantity of (210)Po and thorium isotopes is transferred from the tobacco to the smoker's lungs. Cigarette ash and smoked filters were also collected and analysed. Among the determined isotopes, (210)Pb and (210)Po showed the highest activity concentrations. During the smoking of one cigarette approximately 22% of (210)Po (and presumably its predecessor (210)Pb), 0.6% of (228)Th, 24% of (230)Th, and 31% of (232)Th are transferred from the cigarette and retained in the smoker's body. The estimated annual effective dose for smokers is 61 μSv/year from (210)Po; 9 μSv/year from (210)Pb; 6 μSv/year from (228)Th; 47 μSv/year from (230)Th, and 37 μSv/year from (232)Th. These results show the importance of thorium isotopes in contributing to the annual effective dose for smoking. PMID:26942842

  7. Effect of precursor concentration on the electrical properties of LiFePO4 prepared by solvothermal method

    NASA Astrophysics Data System (ADS)

    Rabbani, Ahmad Yasin; Fakhri, Hafizh A.; Arifin, Muhammad; Aimon, Akfiny Hasdi; Iskandar, Ferry

    2016-02-01

    Lithium iron phosphate (LiFePO4) is frequently used for Li-ion battery cathode. LiFePO4 has the high specific capacity at 170 mAhg-1, stable voltage at 3.45 V, stable structure, cheap, and low toxicity. The objective of this research is investigating the effect of precursor concentration on the electrical properties of LiFePO4 prepared by solvothermal method. LiOH, FeSO4, H3PO4, and citric acid were used as the precursors. The LiOH concentration was varied from 0.3 M to 1.8 M. The Fourier Transform Infrared Spectroscopy (FTIR) measurement identified the Fe-O, O-P-O, and P-O bonds which corresponding to LiFePO4. The result of 4-point probe measurement shows that, among the prepared samples, the sample from the precursor concentration of 1.8 M has the highest electrical conductivity.

  8. Natural radionuclides (210)Po and (210)Pb in the Delaware and Chesapeake Estuaries: modeling scavenging rates and residence times.

    PubMed

    Marsan, D; Rigaud, S; Church, T

    2014-12-01

    During the spring and summer months of 2012, (210)Po and (210)Pb activity were measured in the dissolved and particulate phases from the Delaware and upper Chesapeake estuaries. The upper Delaware estuary, near the freshwater end member, was characterized by high-suspended matter concentrations that scavenged dissolved (210)Po and (210)Pb. Box models were applied using mass balance calculations to assess the nuclides residence times in each estuary. Only 60% of the dissolved (210)Po and 55% of the dissolved (210)Pb from the Delaware estuary were exported to coastal waters. A large fraction of soluble (210)Po and (210)Pb within the estuary was either reversibly adsorbed onto suspended particles, trapped in sediment accumulation zones (such as intertidal marshes), bioaccumulated into phytoplankton and discharged to the coastal ocean. The upper Chesapeake estuary was largely characterized by sub-oxic bottom waters that contained higher concentrations of dissolved (210)Po and (210)Pb, hypothesized to be subjected to redox cycling of manganese. The Delaware and Chesapeake estuary mean residence times for (210)Po differed significantly at 86 ± 7 and 126 ± 10 days respectively, while they were similar for (210)Pb (67 ± 6-55 ± 5 days). The difference in residence times corresponds to the greater extent of biogeochemical scavenging and regeneration processes within the upper Chesapeake. PMID:25239647

  9. Vibrational spectroscopy of the phosphate mineral kovdorskite-Mg2PO4(OH)·3H2O.

    PubMed

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

    2013-10-01

    The mineral kovdorskite Mg2PO4(OH)·3H2O was studied by electron microscopy, thermal analysis and vibrational spectroscopy. A comparison of the vibrational spectroscopy of kovdorskite is made with other magnesium bearing phosphate minerals and compounds. Electron probe analysis proves the mineral is very pure. The Raman spectrum is characterized by a band at 965 cm(-1) attributed to the PO4(3-) ν1 symmetric stretching mode. Raman bands at 1057 and 1089 cm(-1) are attributed to the PO4(3-) ν3 antisymmetric stretching modes. Raman bands at 412, 454 and 485 cm(-1) are assigned to the PO4(3-) ν2 bending modes. Raman bands at 536, 546 and 574 cm(-1) are assigned to the PO4(3-) ν4 bending modes. The Raman spectrum in the OH stretching region is dominated by a very sharp intense band at 3681 cm(-1) assigned to the stretching vibration of OH units. Infrared bands observed at 2762, 2977, 3204, 3275 and 3394 cm(-1) are attributed to water stretching bands. Vibrational spectroscopy shows that no carbonate bands are observed in the spectra; thus confirming the formula of the mineral as Mg2PO4(OH)·3H2O. PMID:23778171

  10. Photocatalytic Performances of Ag3PO4 Polypods for Degradation of Dye Pollutant under Natural Indoor Weak Light Irradiation.

    PubMed

    Teng, Fei; Liu, Zailun; Zhang, An; Li, Min

    2015-08-18

    It is still a big challenge for Ag3PO4 to be applied in practice mainly because of its low stability resistant to photo corrosion, although it is an efficient photocatalyst. Herein, we have mainly investigated its activity and stability under indoor weak light for the degradation of dye pollutants. It is amazing that under indoor weak light irradiation, rhodamine B (RhB) can be completely degraded by Ag3PO4 polypods after 36 h, but only 18% of RhB by N-doped TiO2 after 120 h. It is found that under indoor weak light irradiation, the degradation rate (0.08099 h(-1)) of RhB over Ag3PO4 polypods are 46 times higher than that (0.00173 h(-1)) of N-doped TiO2. The high activity of Ag3PO4 polypods are mainly attributed to the three-dimensional branched nanostructure and high-energy {110} facets exposed. After three cycles, surprisingly, Ag3PO4 polypods show a high stability under indoor weak light irradiation, whereas Ag3PO4 have been decomposed into Ag under visible light irradiation with an artificial Xe light source. This natural weak light irradiation strategy could be a promising method for the other unstable photocatalysts in the degradation of environmental pollutants.

  11. Natural radionuclides (210)Po and (210)Pb in the Delaware and Chesapeake Estuaries: modeling scavenging rates and residence times.

    PubMed

    Marsan, D; Rigaud, S; Church, T

    2014-12-01

    During the spring and summer months of 2012, (210)Po and (210)Pb activity were measured in the dissolved and particulate phases from the Delaware and upper Chesapeake estuaries. The upper Delaware estuary, near the freshwater end member, was characterized by high-suspended matter concentrations that scavenged dissolved (210)Po and (210)Pb. Box models were applied using mass balance calculations to assess the nuclides residence times in each estuary. Only 60% of the dissolved (210)Po and 55% of the dissolved (210)Pb from the Delaware estuary were exported to coastal waters. A large fraction of soluble (210)Po and (210)Pb within the estuary was either reversibly adsorbed onto suspended particles, trapped in sediment accumulation zones (such as intertidal marshes), bioaccumulated into phytoplankton and discharged to the coastal ocean. The upper Chesapeake estuary was largely characterized by sub-oxic bottom waters that contained higher concentrations of dissolved (210)Po and (210)Pb, hypothesized to be subjected to redox cycling of manganese. The Delaware and Chesapeake estuary mean residence times for (210)Po differed significantly at 86 ± 7 and 126 ± 10 days respectively, while they were similar for (210)Pb (67 ± 6-55 ± 5 days). The difference in residence times corresponds to the greater extent of biogeochemical scavenging and regeneration processes within the upper Chesapeake.

  12. Radioactivity of cigarettes and the importance of (210)Po and thorium isotopes for radiation dose assessment due to smoking.

    PubMed

    Kubalek, Davor; Serša, Gregor; Štrok, Marko; Benedik, Ljudmila; Jeran, Zvonka

    2016-05-01

    Tobacco and tobacco smoke are very complex mixtures. In addition to various chemical and organic compounds they also contain natural radioactive elements (radionuclides). In this work, the natural radionuclide activity concentrations ((234)U, (238)U, (228)Th, (230)Th, (232)Th, (226)Ra, (210)Pb and (210)Po) of nine different cigarette samples available on the Slovenian market are reported. In addition to (210)Po, the transfer of thorium isotopes from a cigarette to a smoker's body and lungs have been determined for the first time. Cigarette smoke and exhaled air from smokers' lungs were collected from volunteer smokers (C-4 brand) to determinate what quantity of (210)Po and thorium isotopes is transferred from the tobacco to the smoker's lungs. Cigarette ash and smoked filters were also collected and analysed. Among the determined isotopes, (210)Pb and (210)Po showed the highest activity concentrations. During the smoking of one cigarette approximately 22% of (210)Po (and presumably its predecessor (210)Pb), 0.6% of (228)Th, 24% of (230)Th, and 31% of (232)Th are transferred from the cigarette and retained in the smoker's body. The estimated annual effective dose for smokers is 61 μSv/year from (210)Po; 9 μSv/year from (210)Pb; 6 μSv/year from (228)Th; 47 μSv/year from (230)Th, and 37 μSv/year from (232)Th. These results show the importance of thorium isotopes in contributing to the annual effective dose for smoking.

  13. Enhanced electrochemical performance in LiFePO4/graphene nanocomposite cathode material for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Dhindsa, Kulwinder; Mandal, B.; Lin, M. W.; Nazri, M.; Vaishnava, P.; Naik, V.; Nazri, G. A.; Naik, R.; Zhou, Z. X.

    2012-02-01

    We synthesized LiFePO4/graphene nano-composite employing a sol-gel method, where graphene oxide solution was added to the LiFePO4 precursors during the synthesis. Electrical measurement reveals that the addition of 10% graphene (by weight) to LiFePO4 increases its conductivity by 5 orders of magnitude. SEM images of the composite show that the material consists of LiFePO4 nanoparticles (with a mean particle size ˜ 50 nm) homogeneously mixed with graphene sheets; the latter provides a three-dimensional conducting network for Li+ ion and electron transport. A large specific capacity of 170 mAh/g was observed at a discharge rate of C/2. To further increase the conductivity and inhibit particle size growth of LiFePO4 (thus to increase the rate capacity), we coated the nanoparticles with a thin carbon layer by adding 0.25M lauric acid as precursor in addition to graphene oxide during the synthesis. The respective roles of graphene and lauric-acid-induced carbon coating in the specific capacity and charge-discharge rate of the LiFePO4 cathode material will be discussed.

  14. The influence of reduced graphene oxide on electrical conductivity of LiFePO4-based composite as cathode material

    NASA Astrophysics Data System (ADS)

    Arifin, Muhammad; Aimon, Akfiny Hasdi; Winata, Toto; Abdullah, Mikrajuddin; Iskandar, Ferry

    2016-02-01

    LiFePO4 is fascinating cathode active materials for Li-ion batteries application because of their high electrochemical performance such as a stable voltage at 3.45 V and high specific capacity at 170 mAh.g-1. However, their low intrinsic electronic conductivity and low ionic diffusion are still the hindrance for their further application on Li-ion batteries. Therefore, the efforts to improve their conductivity are very important to elevate their prospecting application as cathode materials. Herein, we reported preparation of additional of reduced Graphene Oxide (rGO) into LiFePO4-based composite via hydrothermal method and the influence of rGO on electrical conductivity of LiFePO4-based composite by varying mass of rGO in composition. Vibration of LiFePO4-based composite was detected on Fourier Transform Infrared Spectroscopy (FTIR) spectra, while single phase of LiFePO4 nanocrystal was observed on X-Ray Diffraction (XRD) pattern, it furthermore, Scanning Electron Microscopy (SEM) images showed that rGO was distributed around LiFePO4-based composite. Finally, the 4-point probe measurement result confirmed that the optimum electrical conductivity is in additional 2 wt% rGO for range 1 to 2 wt% rGO.

  15. Non-random cation distribution in hexagonal Al 0.5Ga 0.5PO 4

    NASA Astrophysics Data System (ADS)

    Kulshreshtha, S. K.; Jayakumar, O. D.; Sudarsan, V.

    2010-05-01

    Based on powder X-ray diffraction and 31P Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) investigations of mixed phosphate Al 0.5Ga 0.5PO 4, prepared by co-precipitation method followed by annealing at 900 °C for 24 h, it is shown that Al 0.5Ga 0.5PO 4 phase crystallizes in hexagonal form with lattice parameter a=0.491(2) and c=1.106(4) nm. This hexagonal phase of Al 0.5Ga 0.5PO 4 is similar to that of pure GaPO 4. The 31P MAS NMR spectrum of the mixed phosphate sample consists of five peaks with systematic variation of their chemical shift values and is arising due to existence of P structural units having varying number of the Al 3+/Ga 3+ cations as the next nearest neighbors in the solid solution. Based on the intensity analysis of the component NMR spectra of Al 0.5Ga 0.5PO 4, it is inferred that the distribution of Al 3+ and Ga 3+ cations is non-random for the hexagonal Al 0.5Ga 0.5PO 4 sample although XRD patterns showed a well-defined solid solution formation.

  16. Engaging Scientists in Meaningful E/PO: How the NASA SMD E/PO Community Addresses Informal Educators' Preferences for PD and Materials

    NASA Astrophysics Data System (ADS)

    Bartolone, Lindsay; Nelson, Andi; Smith, Denise A.; NASA SMD Astrophysics E/PO Community

    2015-01-01

    The NASA Astrophysics Science Education and Public Outreach Forum (SEPOF) coordinates the work of NASA Science Mission Directorate (SMD) Astrophysics EPO projects. These teams work together to capitalize on the cutting-edge discoveries of NASA Astrophysics missions to support educators in Science, Technology, Engineering, and Math (STEM) and to enable youth to engage in doing STEM inside and outside of school. The Astrophysics Forum assists scientists and educators with becoming involved in SMD E/PO, which is uniquely poised to foster collaboration between scientists with content expertise and educators with pedagogy expertise, and makes SMD E/PO resources and expertise accessible to the science and education communities. Informal educators participated in a recent nationally-distributed survey from the NASA SMD SEPOF Informal Education Working Group. The results show the preferences of staff from museums, parks, public libraries, community/afterschool centers, and others with regard to professional development and material resources. The results of the survey will be presented during this session.In addition, we present opportunities for the astronomy community to participate in collaborations supporting the NASA SMD efforts in K-12 Formal Education, Informal Science Education, and Outreach. These efforts focus on enhancing instruction, as well as youth and public engagement, in STEM via use of research-based best practices, collaborations with libraries, partnerships with local and national organizations, and remote engagement of audiences. The Forums' efforts for the Formal, Informal Science Education and Outreach communities include a literature review, appraisal of informal educators' needs, coordination of audience-based NASA resources and opportunities, professional development, plus support with the Next Generation Science Standards. Learn how to join in our collaborative efforts to support the K-12 Formal Education community and to reach the informal

  17. Caractérisation et étude structurale de NaHo(PO3)4

    NASA Astrophysics Data System (ADS)

    Amami, J.; Horchani, K.; Merle, D.; Férid, M.

    2004-12-01

    Crystals of NaHo(PO3)4 have been grown by the flux technique and characterized by X-ray diffraction and infrared spectroscopy. Single crystal structure of NaHo(PO3)4 has been solved, it crystallizes in the monoclinic P23/n space group with lattice parameters : a = 9,699(4), b = 13,0441(5), c = 7,1614(3) Å , ß = 89,314(1)° , Z = 4. The crystal structure has been refined yielding a final R(F2) = 0.033 for 2064 independent reflections (Fo2 ≥ 2σ(Fo2)). The NaHo(PO3)4 structure is characterized by helical ribbons (PO3)∞ running along the c-axis. The HoO8 and NaO7 polyhedra form zigzag chains with common faces and surrounded by four (PO3)∞ chains Le polyphosphate NaHo(PO3)4 est synthétisé, sous forme de monocristaux, par la méthode de flux; ce composé est caractérisé par diffraction RX et spectroscopie de vibration IR. L’étude structurale de NaHo(PO3)4 a montré que ce polyphosphate cristallise dans le système monoclinique, de groupe d’espace P21/n, les paramètres de maille sont : a = 9,699(4), b = 13,0441(5), c = 7,1614(3) Å , ß = 89,314(1)° , Z = 4. L’affinement conduit à un facteur de confiance R1= 3,3 % pour 2064 réflexions indépendantes. La structure de NaHo(PO3)4 est caractérisée par une chaîne hélicoïdale (PO3)∞ se développant le long de l’axe c. Les polyèdres HoO8 et NaO7 forment des chaînes en zigzag possédant des faces en commun et entourés par quatre chaînes (PO3)∞.

  18. Synthesis, characterization and vibrational spectroscopic study of Co, Mg co-doped LiMnPO4

    NASA Astrophysics Data System (ADS)

    Sronsri, Chuchai; Noisong, Pittayagorn; Danvirutai, Chanaiporn

    2016-01-01

    The isostructural olivine-like LiM(II)PO4 compounds [M(II) = Mn, Mn0.9Co0.1, Mn0.8Co0.1Mg0.1] were successfully generated through the solid state reaction from the synthesized NH4M(II)PO4• H2O precursors. The TG/DTG/DTA, AAS/AES, FTIR and XRD methods were employed to confirm both NH4M(II)PO4• H2O and LiM(II)PO4 compounds. Their morphologies were studied by SEM method. The shift of two theta angle of XRD to higher values was observed in metal doping compounds, which indicate the formation of the single phase of isodivalent doping of Co2 + and Mg2 + ions according to the change in the lattice parameters and cell volumes. Their infrared spectra are reported and discussed with respect to the normal vibrations of NH4+, PO43 -, P2O74 - and H2O molecules using factor group analysis. The correlation field splitting analysis of PO43 - in NH4M(II)PO4• H2O (orthorhombic system, Pmn21, C2v7 and Z = 2, [(3 × 5) - 6] × 2 = 18 internal modes) symbolized as Td - Cs - C2v7 suggested the number of vibrational modes to be: ΓVib = A1(6) + A2(3) + B1(6) + B2(3) and A1(6) + A2(3) + B1(3) + B2(6) for zx and yz plane respectively. While, LiM(II)PO4 crystallizes in the orthorhombic system the space group Pnma (D2h16), Z = 4 and the site symmetry of PO43 - is Cs. The correlation field splitting of type Td - Cs - D2h16 were reported in relation to [(3 × 5) - 6] × 4 = 36 internal modes for PO43 - unit in the structure.

  19. PuPO4(cr, hyd.) Solubility Product and Pu3+ Complexes With Phosphate and Ethylenediaminetetraacetic Acid

    SciTech Connect

    Rai, Dhanpat; Moore, Dean A.; Felmy, Andrew R.; Rosso, Kevin M.; Bolton, Harvey

    2010-06-15

    To determine the solubility product of PuPO4(cr, hyd.) and the complexation constants of Pu(III) with phosphate and EDTA, the solubility of PuPO4(cr, hyd.) was investigated as a function of: 1) time and pH varying from 1.0 to 12.0 and at a fixed 0.00032 M phosphate concentration; 2) NaH2PO4 concentrations varying from 0.0001 M to 1.0 M and at a fixed pH value of 2.5; 3) time and pH varying from 1.3 to 13.0 at fixed concentrations of 0.00032 M phosphate and 0.0004 M or 0.002 M Na2H2EDTA; and 4) Na2H2EDTA concentrations varying from 0.00005 M to 0.0256 M at a fixed 0.00032 M phosphate concentration and at pH values of approximately 3.5, 10.6, and 12.6. A combination of solvent extraction and spectrophotometric techniques confirmed that the use of hydroquinone and Na2S2O4 helped maintain Pu as Pu(III). The solubility data were interpreted using Pitzer and SIT models, and both provided similar values for the solubility product of PuPO4(cr, hyd.) and for the formation constant of PuEDTA-. The log10 of the solubility product of PuPO4(cr, hyd.) (PuPO4(cr, hyd.) = Pu3+ + PO4 ) was determined to be –(24.42 ± 0.38). Pitzer modeling showed that phosphate interactions with Pu3+ were extremely weak and did not require any phosphate complexes (e.g., PuPO4(aq), PuH2PO42+, Pu(H2PO4)2+, Pu(H2PO4)3(aq), and Pu(H2PO4)4-), as proposed in existing literature, to explain the experimental data. SIT modeling, however, required the inclusion of PuH2PO42+ to explain the data in high NaH2PO4 concentrations; this illustrates the differences one can expect when using these two chemical models to interpret the data. As the Pu(III)-EDTA species, only PuEDTA- was needed to interpret the experimental data in a large range in pH values (1.3–12.9) and EDTA concentrations (0.00005–0.256 M). Calculations based on density functional theory support the existence of PuEDTA- (with prospective stoichiometry as Pu(OH2)3EDTA-) as the chemically and structurally stable species. The log10 of the

  20. 210Pb and 210Po concentrations in Italian cigarettes and effective dose evaluation.

    PubMed

    Taroni, Mattia; Zagà, Vincenzo; Bartolomei, Paolo; Gattavecchia, Enrico; Pacifici, Roberta; Zuccaro, Piergiorgio; Esposito, Massimo

    2014-09-01

    It has been known for a long time that cigarette tobacco contains naturally occurring radioactive nuclides such as 210Pb and 210Po. In this study, the concentrations of 210Pb and 210Po in the 10 most widely sold cigarette brands in Italy during the year 2010 were measured, and the effective dose to smokers has been calculated. The results of this study show that 210Pb concentration ranged from 11.6 to 20.0 mBq cig-1 with an arithmetic mean of 14.6 mBq cig-1, while the activity concentration of 210Po ranged from 13.1 to 19.0 mBq cig-1 with an arithmetic mean of 15.7 mBq cig-1, thus confirming previous results and showing that the radioactivity concentration was not reduced in the last few years. The annual effective dose for a typical smoker consuming 20 cigarettes per day ranged from an average of 55 μSv y-1 to about 81 μSv y-1. It is finally put in evidence the need to improve the knowledge about crucial data needed for accurate dose assessment deriving from the inhalation of both radioisotopes contained in the cigarettes, namely the dose conversion coefficients, which strongly depend on several parameters such as the inhalation speed through the mouth, the real fraction of radionuclide transferred from cigarette to mainstream smoke, the lung absorption behavior of the radioisotopes inhaled with mainstream smoke, and the AMAD of particles inhaled by smokers.