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Sample records for po lewostronnej adrenalektomii

  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. PMID:25846750

  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. 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

  6. Ultraviolet luminescence of ScPO4, AlPO4 and GaPO4 crystals.

    PubMed

    Trukhin, Anatoly N; Shmits, Krishjanis; Jansons, Janis L; Boatner, Lynn A

    2013-09-25

    The luminescence of self-trapped excitons (STEs) was previously observed and described for the case of tetragonal-symmetry ScPO4 single crystals. The subject band in this material is situated in the UV spectral range of ∼210 nm or ∼5.8 eV. In the present work, we are both expanding this earlier luminescence study and seeking to identify similar luminescence phenomena in other orthophosphate crystals, i.e., AlPO4 and GaPO4. These efforts have proven to be successful--in spite of the structural differences between these materials and ScPO4. Specifically we have found that for AlPO4 and GaPO4, in addition to an α-quartz-like STE, there is a UV luminescence band that is similar in position and decay properties to that of ScPO4 crystals. Potentially this represents an STE in AlPO4 and GaPO4 crystals that is analogous to the STE of ScPO4 and other orthophosphates. The decay kinetics of the UV luminescence of ScPO4 was studied over a wide temperature range from 8 to 300 K, and they exhibited some unusual decay characteristics when subjected to pulses from an F2 excimer laser (157 nm). These features could be ascribed to a triplet state of the STE that is split in a zero magnetic field. A fast decay of the STE was detected as well, and therefore, we conclude that, in addition to the slow luminescence corresponding to a transition from the triplet state, there are singlet-singlet transitions of the STE. Time-resolved spectra of the slow and fast decay exhibit a small shift (∼0.15 eV) indicating that the singlet-triplet splitting is small and the corresponding wavefunction of the STE is widely distributed over the atoms of the ScPO4 crystal where the STE is created. PMID:23988905

  7. 210Po bioaccumulation by mushrooms from Poland.

    PubMed

    Skwarzec, B; Jakusik, A

    2003-10-01

    The paper presents results on 210Po activity concentration measured in mushroom samples collected in northern Poland (Białogard and Elblag areas). Among 20 species of wild mushrooms, King Bolete (Boletus edulis), accumulated 210Po in the highest degree. Therefore this species of higher mushrooms is an excellent bioindicator for 210Po radioactivity in the land environment. Finally, the effective dose of polonium emission was calculated for a consumer of King Bolete. Wild mushroom consumption contributed up to 37 microSv to the effective dose in an individual consuming about 5 kg (fresh weight) of heavily contaminated Boletus edulis species per year. PMID:14587851

  8. Aspects on the analysis of 210Po.

    PubMed

    Henricsson, F; Ranebo, Y; Holm, E; Roos, P

    2011-05-01

    There has been little development regarding analysis of polonium (Po) in environmental samples since the 1960 ies. This is due to the straightforward spontaneous deposition of this element on silver (Ag), nickel (Ni) or copper (Cu) without any radiochemical separation. For many years, no radiochemical yield determinant was used and it was generally supposed that the yield was 100% after two depositions. Counting was often done using ZnS scintillation counter coupled to a photomultiplier tube. However, the use of the yield determinants (208)Po and (209)Po and the development of alpha spectrometry showed that the yield was lower. Furthermore, the tendency of Po to volatilize at low temperatures constrains the sample preparation techniques; dry-ashing cannot be used. But during the wet-ashing procedure, there are still some losses. The aim of this study was to evaluate the Po losses during wet-ashing by the use of a double-tracer technique. We have found that the losses were about 30% when open glass beakers were used and about 17% when the samples were digested in microwave oven. When long-necked bottles (Kjeldahl flasks) were used, a loss of about 20% was registered. It has also been observed that (210)Pb to some extent is plating out together with its daughter nuclide Po during the electrochemical deposition. This will result in a systematic error since an unknown amount of supported (210)Po will be produced from the (210)Pb decay depending on the fraction of (210)Pb being deposited on the disc and the waiting time between deposition and measurement of the sample. A further consequence of this is that in the assessment of the (210)Pb content in the sample, very often the remaining liquid is stored after deposition for build-up of (210)Po. Since some (210)Pb is lost on the disc, the result for (210)Pb will be too low. Both these systematic errors give rise to a too high (210)Po/(210)Pb ratio. The fraction of (210)Pb which is plating out has been assessed in this

  9. 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

  10. Characterization of the Shark Myelin Po Protein

    PubMed Central

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

    2008-01-01

    Myelin, the insulating sheath made by extensive plasma membrane wrappings 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 point to it as a crucial component in the development of myelin as a multi-lamellar membrane structure. Sharks, which appeared in evolution about 400 million years ago, are the first fully myelinated organisms. In this study we set out to investigate the expression pattern of shark myelin Po as a way of understanding how it might have played a role in the evolution of myelin in the central nervous system. We found that shark have more than two isoforms (32, 28 and 25kD), and that some of these might not be fully functional because they lack the domains known for Po homophilic adhesion. PMID:18635929

  11. The Po: Centuries of river training

    NASA Astrophysics Data System (ADS)

    Earchi, E.; Roth, G.; Siccardi, F.

    1995-12-01

    The Po river drains the largest morphological unit of the Italian territory. River training works started in the lower Po during the Roman Age and developed upstream, first as discontinuous systems, then connected to form two uninterrupted belts, which have reduced the overflow frequency but also the storage capacity of the river flood bed. The outcome is an increasing value of the flood peak with given probability in the lower Po, which is the reach with the higher flooding risk. On the other hand, the upstream catchment, in which the river is provided with partial embankments, recently experienced a flooding event and require some form of protection. A risk mitigation policy should perceive and take into account all the components of the river system and their connections. In this perspective the development of traditional structural protection along the Po river has reached a critical stage; a further expansion of the existing levee system increases the down-stream risk. From the viewpoint of non structural protection, the river morphology and the past experience suggest that, based on rainfall and discharge monitoring, early warnings of flood hazards can be provided to communities that could be affected by such occurrences. Finally, to reduce the flooding risk in the lower Po a reduction of the flood discharge entering this reach is needed. This can be obtained by diverting the higher part of the flood from the river immediately upstream of the lower Po, allowing the inundation and the temporary storage of the diverted water on pre-designed large agricultural areas. Implementing such a policy will require a reliable system of flood warning and, above all, a sound regulatory authority.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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...

  18. 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...

  19. 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.

  20. Population and Decay of Superdeformed ^198Po

    NASA Astrophysics Data System (ADS)

    Johnson, M. S.; Cizewski, J. A.; Smith, M. B.; Thomas, J. S.; Becker, J. A.; Bernstein, L. A.; McNabb, D. P.; Schiller, A.; Fallon, P.; Macchiavelli, A. O.; Ward, D.

    2002-10-01

    The population and decay of superdeformed (SD) nuclei remains an area of current interest. Little is known about the entry distribution associated with the population of SD excitations, especially in more fissile systems where fission dominates at high angular momentum. The study of the quasicontinuous (QC) spectrum associated with SD excitations provides a probe of the feeding and decay of the SD band as well as information on the excitation energy and spin of SD states. To study the population and decay of SD states, the ^174Yb(^29Si,5n) reaction was used to populate excitations in ^198Po, the most fissile nucleus for which an SD band has been identified at high spin (D.P. McNabb et al.), Phys. Rev. C 53 R541 (1996). The measurements were performed at the 88-Inch Cyclotron facility at LBNL using the Gammasphere array with 101 Compton-suppressed Ge detectors. The present results for the entry distribution and QC spectrum for the SD band in ^198Po will be contrasted to the spectra associated with the ND excitations in ^198Po, as well as the results for ^195Pb and ^192,194Pb footnote D.P. McNabb et al., Phys. Rev. C 61, 031304(R) (2000) for which similar analyses have been reported.

  1. 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.

  2. Manduca sexta prophenoloxidase (proPO) activation requires proPO-activating proteinase (PAP) and serine proteinase homologs (SPHs) simultaneously.

    PubMed

    Gupta, Snehalata; Wang, Yang; Jiang, Haobo

    2005-03-01

    In the tobacco hornworm Manduca sexta, proteolytic activation of prophenoloxidase (proPO) is mediated by three proPO-activating proteinases (PAPs) and two serine proteinase homologs (SPHs) (Proceedings of the National Academy of Sciences, USA 95 (1998) 12220-12225; J. Biol. Chem. 278 (2003a) 3552-3561; Insect Biochem. Mol. Biol. 33 (2003b) 1049-1060). While our current data are consistent with the hypothesis that the SPHs serve as a cofactor/anchor for PAPs (Insect Biochemistry and Molecular Biology 33 (2003) 197-208; Insect Biochemistry and Molecular Biology 34 (2004) 731-742), roles of these clip-domain proteins (i.e. PAPs and SPHs) in proPO activation are poorly defined. To better understand this process, we further characterized the activation reaction using proPO, PAP-1 and SPHs. PAP-1 itself cleaved nearly 1/3 of proPO at Arg51 without generating much phenoloxidase (PO) activity. In the presence of SPHs, the cleavage of proPO became more complete while the increase in PO activity was over 20-fold, indicating that the extent of cleavage does not directly correlate with PO activity. Since SPHs and p-amidinophenyl methanesulfonyl fluoride (APMSF)-treated PAP-1 did not generate active PO by interacting with proPO, proteolytic cleavage is critical for proPO activation. After 1/5 of proPO was processed by PAP-1 alone which was then inactivated by M. sexta serpin-1J or APMSF, further incubation of the reaction mixture with SPHs failed to generate active PO either. Thus, SPHs cannot generate PO activity by simply binding to cleaved proPO. M. sexta proPO activation requires active PAP-1 and SPHs at the same time-one for limited proteolysis and the other as a cofactor, perhaps. Gel filtration chromatography and native gel electrophoresis revealed the PAP-SPH, proPO-PAP, and SPH-proPO associations, essential for generating high Mr, active PO at the site of infection. PMID:15705503

  3. 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}.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. Thermoplastic polyurethane (TPU)/polyolefin (PO) blends

    NASA Astrophysics Data System (ADS)

    Lu, Qiwei

    Thermoplastic polyurethane (TPU) is a very important material with high versatility and superior physical properties. Melt blending TPU with metallocene polyolefin (PO) can lower TPU cost and improve polyolefin properties like abrasion resistance, adhesion, and paintability. Since TPU and non-polar PO blends are completely immiscible, efficient compatibilizers become the key issue and remain challenging. My main thesis work is to develop and study compatibilized TPU/PO blends. Although reactive compatibilization is considered the most efficient method, fast interfacial reactions between highly reactive functional groups are necessary to generate compatibilizers within usually short processing time. It is known that the urethane linkage (carbamate -NHCOO-) in TPU can reversibly dissociate to generate highly reactive isocyanates at melt temperatures. To find out the best reactive compatibilization, three approaches were employed on different molecular scales: (1) model urethane compound (dibutyl & dioctyl 4,4'-methylenebis(phenyl carbamate)) and small functional molecule (primary amine, secondary amine, hydroxyl, acid, anhydride, and epoxide) reactions at 200°C monitored by nuclear magnetic resonance and Fourier-transform infrared to examine the basic chemistry; (2) short, model TPU's with different chemical structures blended with functional polymers including poly(ethylene glycol) and polybutadiene to explore the effect of interface in immiscible mixtures; (3) melt blending of a commercial TPU with polypropylene (PP), further involving more complicated morphology, using different types of functional PP's (note: amine functional PP's were prepared by melt amination) as compatibilizers followed by rheological, morphological, thermal, and mechanical characterizations. Besides the core thesis project on TPU blends, other related work that has been accomplished includes: (1) adhesion between TPU and PP; (2) rheological properties of TPU; (3) block copolymer formation

  9. Specific absorption spectra of hemoglobin at different PO2 levels: potential noninvasive method to detect PO2 in tissues

    NASA Astrophysics Data System (ADS)

    Liu, Peipei; Zhu, Zhirong; Zeng, Changchun; Nie, Guang

    2012-12-01

    Hemoglobin (Hb), as one of main components of blood, has a unique quaternary structure. Its release of oxygen is controlled by oxygen partial pressure (PO2). We investigate the specific spectroscopic changes in Hb under different PO2 levels to optimize clinical methods of measuring tissue PO2. The transmissivity of Hb under different PO2 levels is measured with a UV/Vis fiber optic spectrometer. Its plotted absorption spectral curve shows two high absorption peaks at 540 and 576 nm and an absorption valley at 560 nm when PO2 is higher than 100 mm Hg. The two high absorption peaks decrease gradually with a decrease in PO2, whereas the absorption valley at 560 nm increases. When PO2 decreases to approximately 0 mm Hg, the two high absorption peaks disappear completely, while the absorption valley has a hypochromic shift (8 to 10 nm) and forms a specific high absorption peak at approximately 550 nm. The same phenomena can be observed in visible reflectance spectra of finger-tip microcirculation. Specific changes in extinction coefficient and absorption spectra of Hb occur along with variations in PO2, which could be used to explain pathological changes caused by tissue hypoxia and for early detection of oxygen deficiency diseases in clinical monitoring.

  10. 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.

  11. 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

  12. Local environment and dynamics of PO4 tetrahedra in Na -Al-PO3 glasses and melts

    NASA Astrophysics Data System (ADS)

    Mamedov, S.; Stachel, D.; Soltwisch, M.; Quitmann, D.

    2005-09-01

    Glasses and melts in the system (NaPO3)(1-x)(Al(PO3)3)x were studied with the aim of obtaining information about the structure on the next larger scale beyond the PO4 group. Magic angle spinning NMR was applied to the pure NaPO3 glass and Raman scattering to systems with x =0.00, 0.03, 0.06, 0.15, and 0.60 in the temperature range T =300-1100K. Comparison of the P31 chemical shift between glass and crystalline forms revealed that polymerization of the metaphosphate into tricyclophosphatelike (PO3)33- rings is the dominant structure, ca. 80%, formed by the twofold vertex-joined PO4 groups in the glass. In the Raman study we focused on the prominent polarized band at ca. 1170cm-1 which is due to the symmetric breathing mode of the tetrahedral PO4 group. This band was decomposed into a few Gaussian lines. These component lines could be identified using the NMR results: two narrow components are due to PO4 groups in the tricyclophosphatelike rings, which have either a Na or an Al counterion and a third broad component is due to chain-polymerized (PO3-)n. The variations of the component lines (peak positions, widths, and intensities) with respect to x and T are presented. We derive the shifts of the symmetric breathing mode frequency which are caused by Na or Al counterions, by ring closure, by x >0, etc. The relative intensities of the narrow and broad components in the 1170-cm-1 band of the Raman spectra are discussed. The amount of ring-to-chain transformation on addition of Al3+, and as functions of T and x, is derived. Indications for ordering on a next larger scale, derivable from Raman, NMR, and thermodynamics, are compared.

  13. Population of superdeformed excitations in {sup 198}Po

    SciTech Connect

    Johnson, M.S.; Cizewski, J.A.; Smith, M.B.; Thomas, J.S.; Becker, J.A.; Bernstein, L.A.; Schiller, A.; McNabb, D.P.; Fallon, P.; Macchiavelli, A.O.

    2005-02-01

    Superdeformed excitations in {sup 198}Po were studied using the {sup 174}Yb({sup 29}Si,5n) reaction and {gamma}-ray spectroscopy with Gammasphere. Energy-spin entry distributions for populating normal (ND) and superdeformed (SD) excitations were extracted by gating on discrete ND and SD transitions, respectively. Information on the SD excitation energy, SD well depth, and fission barrier in {sup 198}Po was deduced.

  14. 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.

  15. Spatial distribution of 214Po ions in the electrostatic collection.

    PubMed

    Barlas, E; Bayrak, A; Emirhan, E; Haciomeroglu, S; Ozben, C S

    2013-10-01

    A low cost Si-PIN photodiode-based radon monitor was successfully designed and produced to monitor precursory earthquake indicators in the Northern Anatolian Fault Line. The spatial distribution of (214)Po ions was determined by comparing the 7.69 MeV (214)Po peak in the MCA spectrum and the Geant4 energy distribution of alpha particles at various detector source distances. PMID:23811634

  16. 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...

  17. 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...

  18. 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...

  19. 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

  20. 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

  1. Floodplain Management Strategies for Flood Attenuation in the River Po

    NASA Astrophysics Data System (ADS)

    Brath, A.; Castellarin, A.; di Baldassarre, G.

    2009-12-01

    This paper analyses the effects of different floodplain management policies on flood hazard using a 350km reach of the River Po (Italy) as a case study. The River Po is the longest Italian river, and the largest in terms of streamflow. The middle-lower Po flows East some 350km in the Pianura Padana (Po Valley), a very important agricultural region and industrial heart of Northern Italy. This portion of the river consists of a main channel (200-500m wide) and a floodplain (overall width from 200m to 5km) confined by two continuous artificial embankments. Floodplains are densely cultivated, and a significant portion of these areas is protected against frequent flooding by a system of minor dikes, which impacts significantly the hydraulic behaviour of the middle-lower Po during major flood events. This study aims at investigating the effects of the adoption of different floodplain management strategies (e.g., raising, lowering or removal of the minor dike system) on the hydrodynamics of the middle-lower Po and, in particular, on flood-risk mitigation. This is a crucial task for institutions and public bodies in charge of formulating robust flood risk management strategies for the Po River. Furthermore, the results of the study is of interest for other European water related public bodies managing large river basins, in the light of the recent Directive 2007/60/EC on the assessment and management of flood risks (European Parliament, 2007). The analysis is performed by means of a quasi-2D hydraulic model, which has been developed on the basis of a laser-scanning DTM and a large amount of calibration data recorded during the significant flood event of October 2000.

  2. Pressure-induced amorphization of antiferromagnetic FePO 4

    NASA Astrophysics Data System (ADS)

    Pasternak, M. P.; Rozenberg, G. Kh.; Milner, A. P.; Amanowicz, M.; Brister, K. E.; Taylor, R. D.

    1998-03-01

    In this paper we describe for the first time an unusual phenomenon, occurring in FePO 4 ( TN=25 K), where pressure drives the crystalline low-pressure phase (I) into two, coexisting antiferromagnetic states; one amorphous designated as IIa, the other crystalline (IIb) with an enhanced coordination number. This is unlike the case of berlinite (AlPO 4), which completely amorphizes above 15 GPa. Measurements were carried out with Mössbauer Spectroscopy (MS) and X-ray diffraction (XRD) at CHESS, over the pressure range 0-30 GPa. XRD shows that the double transformation starts at ˜2 GPa reaching saturation at 7 GPa. MS, however, show that the FePO 4-I phase coexists to the highest pressure, indicating possible formation of clusters with sizes undetected by XRD. The abundance of the FePO 4 IIa and IIb phases are about equal. Both XRD and the new TN (=60 K) value obtained by MS, show that the FePO 4-IIa phase is isostructural to CrVO 4. No change is observed in the relative abundance of the three phases at P>7 GPa in which the I-phase constitutes about 10% of the total. The TN value of the FePO 4-II phases increases with increasing pressure, from 50 K at 2.5 GPa to 65 at 25 GPa. The pressure transitions at room temperature are not reversible; after pressure release to ambient value, the FePO 4-I is completely restored only after heat treatment in air at T=700°C.

  3. The December, 1931 absorption experiments by Irene and Fredrick Joliot-Curie using Po Be, PoB and PoLi sources to study penetrating radiation

    NASA Astrophysics Data System (ADS)

    Shafroth, Stephen

    2005-03-01

    The December, 1931 absorption experiments by Irene and Fredrick Joliot-Curie using Po Be, PoB and PoLi sources to study penetrating radiation S.M. Shafroth, Physics and Astronomy Department, University of North Carolina at Chapel Hill 27599-3255, mailto:shafroth@physics.unc.edushafroth@physics.unc.edu The experimental arrangement including the Hoffman electroscope radiation detector and samples of the raw data are shown.^1 The emitted neutrons were interpreted as very high energy penetrating gammas. The exponential decay of detected radiation with thicknesses of Pb from 1.5- 5 cm are shown. I. Curie concludes, based on current knowledge of absorption coefficients vs gamma energy, that the gamma energy from PoBe was 15-20 MeV. However cloud chamber experiments had shown that the ``penetrating radiation'' could eject protons from paraffin with energies of 4.5 and 2 MeV in the case of Be and B respectively. If the ejection mechanism were the Compton effect, the gamma energies had to be 50 and 35 MeV respectively. Finally they conclude that the discrepancy in gamma energies could be ``due to the uncertainties.'' 1. Comptes Rendus de l'Academie des Sciences, S'eance du 28 Decembre 1931

  4. 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

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

    DOE PAGESBeta

    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

  6. Low temperature heat capacity of PuPO 4

    NASA Astrophysics Data System (ADS)

    Thiriet, C.; Konings, R. J. M.; Wastin, F.

    2005-09-01

    PuPO 4 was prepared successfully by coprecipitation and its heat capacity measured between 5 K and 300 K by a hybrid adiabatic relaxation calorimeter. The standard entropy S0 (298.15 K) of PuPO 4 was derived and a semi-empirical method was used to describe the total entropy as the sum of the lattice entropy Slat and the excess entropy Sexs as verified for the iso-electronic lanthanide orthophosphates. Thus the standard entropies of some actinide (III) orthophosphates were estimated.

  7. 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.%.

  8. 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

  9. β-K(VO2)2(PO4).

    PubMed

    Ezzine Yahmed, Safa; Ayed, Meriem; Zid, Mohamed Faouzi; Driss, Ahmed

    2013-01-01

    A new vanadium oxide, potassium bis-(dioxovanad-yl) phosphate, β-K(VO2)2(PO4), has been synthesized by a solid-state reaction. In the title compound, the [V2PO8] framework is built up from infinite pyramidal [V2O8]∞ and [VPO7]∞ chains linked together by V-O-P bridges, leading to a three-dimensional framework which delimits two types of inter-secting tunnels running along [100] and [010] in which the four unique K(+) ions, showing coordination numbers of nine and ten, are located. PMID:23476311

  10. The Imagine the Universe! E/PO Program

    NASA Technical Reports Server (NTRS)

    Lochner, James C.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    Since 1996, the Imagine the Universe! E/PO program has brought information and curriculum support materials to upper middle school, high school, and lower undergraduate students and their teachers on topics in the Structure and Evolution of the Universe (SEU) theme. The Imagine E/PO program consists of a web site, a series of posters and information/activity booklets, and a repertoire of educator workshops. We involve both scientists and educators in the development and testing of the materials. We describe here the various aspects of this program.

  11. 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.

  12. [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

  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. 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.

  15. Measurement of airborne 218Po--a Bayesian approach.

    PubMed

    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. These 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 218Po can be characterized as an "immigration-death process" in the widely adopted, biologically based jargon. The probability distribution for the number of 218Po 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, is also Poisson, with mean dependent on epsilon, t, T, the flowrate and N(o), the number of airborne 218Po 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(o). This density characterizes the remaining uncertainty about the measured number of 218Po atoms per unit volume of air. PMID:8919080

  16. 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.

  17. 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…

  18. 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.

  19. 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.

  20. 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.

  1. Spontaneous Fluctuations of PO2 in the Rabbit Somatosensory Cortex.

    PubMed

    Linsenmeier, Robert A; Aksenov, Daniil P; Faber, Holden M; Makar, Peter; Wyrwicz, Alice M

    2016-01-01

    In many tissues, PO2 fluctuates spontaneously with amplitudes of a few mmHg. Here we further characterized these oscillations. PO2 recordings were made from the whisker barrel cortex of six rabbits with acutely or chronically placed polarographic electrodes. Measurements were made while rabbits were awake and while anesthetized with isoflurane, during air breathing, and during 100% oxygen inspiration. In awake rabbits, 90% of the power was between 0 and 20 cycles per minute (cpm), not uniformly distributed over this range, but with a peak frequently near 10 cpm. This was much slower than heart or respiratory rhythms and is similar to the frequency content observed in other tissues. During hyperoxia, total power was higher than during air-breathing, and the dominant frequencies tended to shift toward lower values (0-10 cpm). These observations suggest that at least the lower frequency fluctuations represent efforts by the circulation to regulate local PO2. There were no consistent changes in total power during 0.5 or 1.5% isoflurane anesthesia, but the power shifted to lower frequencies. Thus, both hyperoxia and anesthesia cause characteristic, but distinct, changes in spontaneous fluctuations. These PO2 fluctuations may be caused by vasomotion, but other factors cannot be ruled out. PMID:26782227

  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.

    2014-06-15

    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.

  3. 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

  4. 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

  5. EPR Studies of the Defect Centers in γ-Irradiated KH2PO4, NH4H2PO4 and Ba(H2PO4)2 Single Crystals: Effects of Impurities and Thermal Annealing

    NASA Astrophysics Data System (ADS)

    Yu, Jiang-Tsu; Lou, Ssu-Hao

    1993-09-01

    The CrO42- impurity has been found to be very effective in stabilizing a phosphorus oxyradical produced by γ-irradiation at room temperature in KH2PO4 and NH4H2PO4 crystals. A similar radical species can be observed in pure Ba(H2PO4)2 crystals γ-irradiated at room temperature. The observed principal values of the g-factor and the 31P hyperfine splitting indicate that this radical species could be the [PO5]2- or [O3POO]2-.

  6. 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.

  7. 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.

  8. Pressure-induced zircon-type to scheelite-type phase transitions in YbPO{sub 4} and LuPO{sub 4}

    SciTech Connect

    Zhang, F.X. Lang, M.; Ewing, R.C. Lian, J.; Wang, Z.W.; Hu, J.; Boatner, L.A.

    2008-10-15

    The tetragonal orthophosphates, YbPO{sub 4} and LuPO{sub 4}, 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 {approx}22 GPa for YbPO{sub 4} and 19 GPa for LuPO{sub 4}. Coinciding with the transition from the zircon structure-type to the scheelite structure-type, there is a {approx}10% reduction in volume and a significant increase in the bulk modulus for both compounds. - Graphical abstract: The tetragonal orthophosphates, YbPO{sub 4} and LuPO{sub 4}, show reversible phase transitions from the zircon structure-type to the scheelite structure-type at {approx}22 and 19 Gpa, respectively. Coinciding with the phase transition, there is a {approx}10% reduction in unit cell volume.

  9. Stability of luminescence in LaPO4, LaPO4 :RE(3+) (RE = Dy, Eu) nanophosphors.

    PubMed

    Pimpalshende, D M; Dhoble, S J

    2015-03-01

    The property of high refractive index, low solubility in water as well as stability to high temperature variation of lanthanum phosphate (LaPO4 ) proved it was the most effective candidate for the production of display lamps, and plasma display panel devices and sensors. The morphological and nanostructural characteristics play a key role in the working efficiency of the luminescent material. These properties can be controlled by the synthesis method, which we have adopted in this paper. We have prepared LaPO4 nanoparticles at a relatively low temperature (110 ºC) in polyethylene glycol medium by using a wet chemical one-step synthesis. The phase composition and structural properties of the sample have been characterized by X-ray diffraction, Fourier transform infrared, transmission electron microscopy and the luminescent property by photoluminescence and thermoluminescence. The samples were well crystallized and the average crystallite size of 15 nm has been calculated for pure LaPO4 using the Debye-Scherrer equation. The result from heat-treated samples shows the phase combination and morphological structure of the powder depend on the annealing temperature. The heat treatment changes the structure of LaPO4 from cuboid rods to fine grains at about 600 °C. The emission spectrum of LaPO4 shows the broad emission band at 368 nm and shoulder at 465 nm with emission of blue color when monitored at an excitation wavelength at 256 nm. The stability of phosphor has been studied with respect to humidity, temperature, doping, doping concentration, γ-ray exposures, etc. The prepared nanosized phosphors were thermally stable and may be a promising blue phosphor for lighting technology as well as radiation dosimetry. PMID:24942642

  10. Formation and diffusion of vacancy-polaron complex in olivine-type LiMnPO4 and LiFePO4

    NASA Astrophysics Data System (ADS)

    Asari, Yusuke; Suwa, Yuji; Hamada, Tomoyuki

    2011-10-01

    Formation and diffusion of a vacancy-polaron complex in olivine-type cathode-active materials, namely, LiMPO4 (M = Fe, Mn), were theoretically investigated by using the first-principles density functional theory within a framework of GGA + U method. It is shown that a lithium vacancy and a corresponding hole-polaron form the complex at the fully lithiated limit owing to lattice distortion and Coulomb interaction between them. It is also shown that the formation energy of the complex in LiMnPO4 is 0.19 eV higher than that in LiFePO4, since a hole polaron in LiMnPO4 is not sufficiently relaxed. As a result, the nucleation rate of MnPO4 phase in LiMnPO4 is 10-3 times slower than that in LiFePO4 and represents the main difference between the kinetics in the initial stage of charging of the two olivine materials. It was also found that the activation energy of the complex diffusion is limited by vacancy hopping in LiMnPO4, while it is determined by both vacancy hopping and polaron hopping in LiFePO4. The activation energy in LiMnPO4, 0.38 eV, is comparable with that in LiFePO4, 0.42 eV. The calculated potential energy profile, showed that the minimum energy path of the diffusing lithium in LiMnPO4 has the same winding shape as that in LiFePO4.

  11. 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.

  12. Alpha radioactivity in cigarette smoke. [/sup 210/Po

    SciTech Connect

    Cohen, B.S.; Eisenbud, M.; Harley, N.H.

    1980-07-01

    The ..cap alpha.. activity of cigarette smoke tar deposited onto membrane filters was found to be associated with the relatively insoluble fraction. Perfusion of the tar with physiological saline resulted in no change in the mean measured activity, but there was more variability in the measured values for the perfused tar than for the initial tar samples. Analysis of cigarette smoke condensate shows that radium and thorium are present, but over 99% of the ..cap alpha.. activity results from /sup 210/Po. Repeat measurements after a time lapse of 2 1/2 years indicate that the initial /sup 210/Pb content of the tar is roughly 30 to 40% of the original /sup 210/Po content for both unprocessed and perfused samples. An increase in the ..cap alpha.. activity concentration of smoke deposited in lung tissue may result from the lack of solubility of the radioactive material compared with other smoke constituents.

  13. PoInTree: a polar and interactive phylogenetic tree.

    PubMed

    Carreras, Marco; Marco, Cerreras; Gianti, Eleonora; Eleonora, Gianti; Sartori, Luca; Luca, Sartori; Plyte, Simon Edward; Edward, Plyte Simon; Isacchi, Antonella; Antonella, Isacchi; Bosotti, Roberta; Roberta, Bosotti

    2005-02-01

    PoInTree (Polar and Interactive Tree) is an application that allows to build, visualize and customize phylogenetic trees in a polar interactive and highly flexible view. It takes as input a FASTA file or multiple alignment formats. Phylogenetic tree calculation is based on a sequence distance method and utilizes the Neighbor Joining (NJ) algorithm. It also allows displaying precalculated trees of the major protein families based on Pfam classification. In PoInTree, nodes can be dynamically opened and closed and distances between genes are graphically represented. Tree root can be centered on a selected leaf. Text search mechanism, color-coding and labeling display are integrated. The visualizer can be connected to an Oracle database containing information on sequences and other biological data, helping to guide their interpretation within a given protein family across multiple species. The application is written in Borland Delphi and based on VCL Teechart Pro 6 graphical component (Steema software). PMID:16144524

  14. 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.

  15. 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.

  16. Synthesis and Electrochemical Properties of LiFePO4/C for Lithium Ion Batteries.

    PubMed

    Gao, Hong; Wang, Jiazhao; Yin, Shengyu; Zheng, Hao; Wang, Shengfu; Feng, Chuanqi; Wang, Shiquan

    2015-03-01

    LiFePO4/C was prepared through a facile rheological phase reaction method by using Fe3(PO4)2, Li3PO4 · 8H2O, and glucose as reactants. The LiFePO4/C samples were characterized by X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis. The electrochemical properties of the samples were investigated. The results show that the LiFePO4/C samples have single-phase olivine-type structure, and their particles feature a spherical shape. The carbon coating on the particles of LiFePO4 is about 1.8% of the LiFePO4/C by weight. The particle size was distributed from 0.2 to 1 µm. The initial discharge capacity of LiFePO4/C reached 154 mA h/g at 0.1 C. The retained discharge capacity of LiFePO4/C was 152.9 mA h g(-1) after 50 cycles. The LiFePO4/C also showed better cycling performance than that of the bare LiPeO4 at a higher charge/discharge rate (1 C). The LIFePO4/C prepared in this way could be a promising cathode material for lithium ion battery application. PMID:26413648

  17. β-NbPO 5 and β-TaPO 5: Bronzoïds, second members of the monophosphate tungsten bronze series (PO 2) 4(WO 3) 2 m

    NASA Astrophysics Data System (ADS)

    Chahboun, H.; Groult, D.; Hervieu, M.; Raveau, B.

    1986-12-01

    The oxides β-NbPO 5 and β-TaPO 5 have been studied by X-ray diffraction and high resolution electron microscopy. They exhibit different supercells based on an orthorhombic subcell with the parameters a0 = 11.27 Å, b0 = 5.28 Å, c0 = 6.62 Å. It is shown that their framework corresponds to the member m = 2 of the series of monophosphate tungsten bronzes (PO 2) 4(WO 3) 2 m with pentagonal tunnels (MPTB P). The structure can thus be described as built up from ReO 3-type slabs which are two octahedra wide and connected through phosphate planes. The stability of these bronzoïds is discussed with respect to that of the MPTB P compounds. The relationships between the structures of the α and β forms of NbPO 5 and TaPO 5 are studied.

  18. 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.

  19. Evidence of 210Po on Martian dust at Meridiani Planum

    NASA Astrophysics Data System (ADS)

    Meslin, Pierre-Yves; Sabroux, Jean-Christophe; Berger, Lionel; Pineau, Jean-François; Chassefière, Eric

    2006-09-01

    Since the Surveyor and Apollo missions and up to the recent Lunar Prospector mission, 222Rn and 210Po have been key isotopes for understanding gas release events and their spatial and temporal variations on the Moon. Comparatively, these isotopes have drawn much less attention on Mars, if any, despite the wealth of information it could bring on the uppermost meters of the regolith, the exchange of volatiles at the surface, and the atmospheric aerosol cycle. Here we present a statistical analysis of the high-energy end of alpha spectra obtained by the alpha particle X-ray spectrometer onboard Mars Exploration Rover Opportunity and report evidence of 210Po, a decay product of 222Rn, attached to atmospheric dust. The 210Po surface activity on rocks and soils at the landing site is lower than 3.1 × 10-4 Bq cm-2, but analysis of spectra obtained on the dust capture magnet reveals a 210Po activity of (4.6 +/- 2.4) × 10-3 Bq cm-2 (+/-2σ). This difference is due to the very low dust cover index at the landing site. Owing to frequent dust devils, regional and global dust storms that mobilize substantial amounts of dust and homogenize the dust surface layer, we infer that the global average 222Rn exhalation rate is significantly greater on Mars than on the Moon. This comparison supports the hypothesis that on Mars, radon emanation could be comparatively enhanced by the presence of water in the surficial soil. Analysis of atmospheric spectra yields a radon activity upper limit of 16 +/- 5 Bq m-3 during nighttime at the landing site.

  20. 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.

  1. 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.

  2. 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).

  3. 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.

  4. Origin of the charge gap in LaMnPO

    DOE PAGESBeta

    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

  5. 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.

  6. The Stanford Solar Observatory Group E/PO Program

    NASA Astrophysics Data System (ADS)

    Scherrer, P. H.

    2003-12-01

    As PI for the SOHO/MDI and SDO/HMI investigations and a Co-I in the NSF CISM STC program I have had the opportunity to help in the formulation and development of a multifaceted education and public outreach program. Our E/PO effort began with a web page and press relations but has grown to include the development of an inexpensive spectrometer with supporting materials, poster development and distribution, and a series of webcasts in collaboration with NASA. The present program, with the support of a dedicated E/PO team, includes the development of a solar planetarium program, and a space weather monitor that can be made available through traditional distribution methods. In collaboration with the Stanford Haas Center for Public Service we are also developing a university course that will teach the essentials of science education as part of a lifetime commitment to public service. The development of the Stanford solar E/PO program and involvement of science professionals in that program will be discussed. (The Michelson Doppler Imager (MDI) is an instrument on the Joint ESA & NASA Solar and Heliospheric Observatory (SOHO) mission. The Helioseismic and Magnetic Imager (HMI), is an instrument on the NASA Solar Dynamics Observatory (SDO) mission which is under development. The Center for Space Weather Modeling (CISM) led by Jeff Hughes at Boston University is an NSF Science and Technology Center.)

  7. 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.

  8. 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

  9. Space matters: Li+ conduction versus strain effect at FePO4/LiFePO4 interface

    NASA Astrophysics Data System (ADS)

    Lv, Weiqiang; Niu, Yinghua; Jian, Xian; Zhang, Kelvin H. L.; Wang, Wei; Zhao, Jiyun; Wang, Zhiming; Yang, Weiqing; He, Weidong

    2016-02-01

    FePO4/LiFePO4 (FP/LFP) interfacial strain, giving rise to substantial variation in interfacial energy and lattice volume, is inevitable in the (de)lithiation process of LiFePO4, a prototype of Li ion battery cathodes. Extensive theoretical and experimental research has been focused on the effect of lattice strain energy on FP/LFP interface propagation orientation and cyclic stability of the electrode. However, the essential effect of strain induced lattice distortion on Li+ transport at the FP/LFP interface is typically overlooked. In this report, a coherent interface model is derived to evaluate quantitatively the correlation between FP/LFP lattice distortion and Li+ conduction. The results illustrate that the effect of lattice strain on Li+ conduction depends strongly on FP/LFP interface orientations. Lattice strain induces a 90% decrease of Li+ conductivity in ac-plane oriented (de)lithiation at room temperature. The opposite effect of lattice strain on delithiation and lithiation for ab- and bc-orientations is elucidated. In addition, the effect of lattice strain tends to be more pronounced at a lower working temperature. This study provides an efficient platform to comprehend and manipulate Li+ conduction in the charge and discharge of lithium ion batteries, the large-scale application of which is frequently challenged by limited in-cell ion conduction.

  10. 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.

  11. 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)

  12. 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.

  13. 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.

  14. Quality assessment of bed sediments of the Po River (Italy).

    PubMed

    Viganò, Luigi; Arillo, Attilio; Buffagni, Andrea; Camusso, Marina; Ciannarella, Ruggero; Crosa, Giuseppe; Falugi, Carla; Galassi, Silvana; Guzzella, Licia; Lopez, Antonio; Mingazzini, Marina; Pagnotta, Romano; Patrolecco, Luisa; Tartari, Gianni; Valsecchi, Sara

    2003-02-01

    Comprehensive and contemporary evaluations of physical, chemical and toxicological endpoints have been performed on bed sediments of the Po River, the major Italian watercourse. Two extensive sampling campaigns were conducted in summer and winter low-flow conditions. Composite sediment samples were collected from ten reaches of the main river: the first was located in the upper region (ambient control), and the others downstream of the confluences of nine principal tributaries. The two sampling programs were paralleled by contemporary investigations on the macroinvertebrate community. The particle-size composition along the Po River showed a relatively uniform distribution of fine sand, a progressive downstream decrease of coarse sands and a corresponding increase of fine materials. The levels of polychlorinated biphenyls (PCB), polycyclic aromatic hydrocarbons (PAH), extractable organo halides (EOX), Cd, Cr, Cu, Hg, Ni, Pb and Zn were determined in sediment fine particles (< 63 microm), and showed marked changes across the ten river reaches. Their longitudinal trends, as those of organic carbon and total nitrogen, were very similar and largely independent of the survey season. Sediment quality benchmarks were used to evaluate sediment chemistry, and, although the overall level of contamination was from moderate to low, the reaches located downstream of the tributaries Dora Riparia, Dora Baltea, Lambro and Oglio were considered to be at risk. Sediments were tested for toxicity on Oncorhynchus mykiss, Ceriodaphnia dubia, Raphidocelis subcapitata and Vibrio fischeri. The toxicity tests were conducted both with sediment extracts and whole samples. Sediment extracts showed toxic potentials that were consistent with the spatial distribution of contaminants. Whole-sediment toxicity showed moderate/low effects which also included false positives and negatives. Alterations of the macroinvertebrate community were found for many kilometers downstream of Dora Riparia, and

  15. Luminescence Properties of ScPO{sub 4} Single Crystals

    SciTech Connect

    Boatner, L.A.; Trukhin, A.N.

    1999-08-16

    Flux-grown ScPO{sub 4} single crystals exhibit a number of luminescence bands in their x-ray-excited luminescence spectra - including sharp lines arising from rare-earth elements plus a number of broad bands at 5.6 cV, 4.4 eV, and 3 eV. The band at 5.6 eV was attributed to a self-trapped exciton (STE) [l], and it could be excited at 7 eV and higher energies. This luminescence is strongly polarized (P = 70 %) along the optical axes of the crystal and exhibits a kinetic decay time constant that varies from several ns at room temperature to {approximately}10 {micro}s at 60 K and up to {approximately}1 ms at 10 K. It is assumed that the STE is localized on the SC ions. The band at 3 eV can be excited in the range of the ScPO{sub 4} crystal transparency (decay time = 3 to 4 {micro}s.) This band is attributed to a lead impurity that creates different luminescence centers. At high temperatures, the band at 4.4 eV is dominant in the x-ray-excited TSL and afterglow spectra. Its intensity increases with irradiation time beginning at zero at the initial irradiation time. The 4.4 eV band does not appear in a fast process under a pulsed electron beam, showing that accumulation is necessary for its observation. A sample of ScPO{sub 4} doped with vanadium exhibited a prevalent band at 4.4 eV at T = 480 K.

  16. 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

  17. Climatology of atmospheric PM10 concentration in the Po Valley

    NASA Astrophysics Data System (ADS)

    Bigi, A.; Ghermandi, G.

    2014-01-01

    The limits to atmospheric pollutant concentration set by the European Commission provide a challenging target for the municipalities in the Po Valley, because of the characteristic climatic conditions and high population density of this region. In order to assess climatology and trends in the concentration of atmospheric particles in the Po Valley, a dataset of PM10 data from 41 sites across the Po Valley have been analysed, including both traffic and background sites (either urban, suburban or rural). Of these 41 sites, 18 with 10 yr or longer record have been analysed for long term trend in de-seasonalized monthly means, in annual quantiles and in monthly frequency distribution. A widespread significant decreasing trend has been observed at most sites, up to few percent per year, by Generalised Least Square and Theil-Sen method. All 41 sites have been tested for significant weekly periodicity by Kruskal-Wallis test for mean anomalies and by Wilcoxon test for weekend effect magnitude. A significant weekly periodicity has been observed for most PM10 series, particularly in summer and ascribed mainly to anthropic particulate emissions. A cluster analysis has been applied in order to highlight stations sharing similar pollution conditions over the reference period. Five clusters have been found, two gathering the metropolitan areas of Torino and Milano and their respective nearby sites and the other three clusters gathering north-east, north-west and central Po Valley sites respectively. Finally the observed trends in atmospheric PM10 have been compared to trends in provincial emissions of particulates and PM precursors, and analysed along with data on vehicular fleet age, composition and fuel sales. Significant basin-wide drop in emissions occurred for gaseous pollutants, contrarily to emissions of PM10 and PM2.5, whose drop resulted low and restricted to few provinces. It is not clear whether the decrease for only gaseous emissions is sufficient to explain the

  18. Ferroelastic shear bands in Pb3(PO4)2

    NASA Astrophysics Data System (ADS)

    Li, Suzhi; Bismayer, Ulli; Ding, Xiangdong; Salje, Ekhard K. H.

    2016-01-01

    We report shear bands as a precursor structure of deformation twinning in Pb3(PO4)2. Atomic force microscopy shows "slip-line" like traces on the surface of untwinned regions of the sample. The traces are shear bands oriented along twin boundaries of the ferroelastic R 3 ¯ m -C2/c transition. Computer simulations reproduce the shear band patterns and show that each shear band is a precursor embryo of a twin wall that forms under higher shear stress. This observation reveals the structural origin of twin boundaries under stress conditions just before ferroelastic switching occurs.

  19. 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).

  20. 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).

  1. 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).

  2. 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).

  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-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).

  5. 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).

  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-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).

  8. 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).

  9. 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

  10. 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).

  11. 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).

  12. 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).

  13. 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).

  14. 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).

  15. 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).

  16. 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).

  17. 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).

  18. 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).

  19. 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

  20. {sup 210}Po and {sup 210}Pb intake by the Portuguese population: The contribution of seafood in the dietary intake of {sup 210}Po and {sup 210}Pb

    SciTech Connect

    Carvalho, F.P.

    1995-10-01

    Through analysis of {sup 210}Po and {sup 210}Pb in the diet, the average ingestion rate for the Portuguese population is estimated at 1.2 and 0.47 Bq d{sup -1} per capita for {sup 210}Po and {sup 210}Pb, respectively. Detailed analysis of foods indicate that seafood alone contributes up to 70% of the {sup 210}Po ingestion rate, whereas cerals, vegetables, and meat altogether contribute 79% of the {sup 210}Pb ingestion rate. Consumption of seafood, both in terms of quantities (kg d{sup -1} per person) and preferential consumption of certain marine species, is the cause of the relatively high intake of {sup 210}Po and high {sup 210}Po:{sup 210}Pb ratio in the diet in comparison with other countries. Other {sup 210}Po and {sup 210}Pb sources, namely inhalation of surface air and cigarette smoke, contribute only a small percentage of the adsorption of these radionuclides in the blood. Estimated total body burdens of {sup 210}Po and {sup 210}Pb in adult men, 70 Bq, are 3.5 times higher than estimates for humans living in normal radioactivity regions and consuming a reference diet. Average whole body effective doses for the adult from the Portuguese population are estimated at about 85 {mu}Sv y{sup -1} from {sup 210}Po and 170 {mu}Sv y{sup -1} from {sup 210}Pb adsorbed with the diet. Effective dose from {sup 210}Po in the diet may vary from 25 {mu}Sv y{sup -1} in an heavy consumer of sardines, to 1,000 {mu}Sv y{sup -1} in an hypothetical heavy consumer of molluscs. 46 refs., 2 figs., 4 tabs.

  1. Controlled synthesis of a highly dispersed BiPO4 photocatalyst with surface oxygen vacancies

    NASA Astrophysics Data System (ADS)

    Wei, Zhen; Liu, Yanfang; Wang, Jun; Zong, Ruilong; Yao, Wenqing; Wang, Juan; Zhu, Yongfa

    2015-08-01

    Highly dispersed BiPO4 with surface oxygen vacancies was synthesized via a solvothermal-calcination method. It can disperse uniformly in water for more than three days and the optimum photocatalytic activity of this highly dispersed BiPO4 was more than twice as high as that of Degussa P25 due to the oxygen vacancies. The high dispersibility is attributed to a layer of organic matter formed on the surface of BiPO4via the solvothermal approach. Most of the organic matter can be removed by calcination at 450 °C, but a small amount remains, thus the calcined BiPO4 retained its high dispersibility. This high dispersibility maintains a good contact between BiPO4 and the pollutants, resulting in the efficient removal of the pollutants by BiPO4. Besides, calcination at 450 °C also induced the formation of oxygen defects in BiPO4, which promotes the separation of photogenerated charge carriers and thus improves the photocatalytic activity of BiPO4.Highly dispersed BiPO4 with surface oxygen vacancies was synthesized via a solvothermal-calcination method. It can disperse uniformly in water for more than three days and the optimum photocatalytic activity of this highly dispersed BiPO4 was more than twice as high as that of Degussa P25 due to the oxygen vacancies. The high dispersibility is attributed to a layer of organic matter formed on the surface of BiPO4via the solvothermal approach. Most of the organic matter can be removed by calcination at 450 °C, but a small amount remains, thus the calcined BiPO4 retained its high dispersibility. This high dispersibility maintains a good contact between BiPO4 and the pollutants, resulting in the efficient removal of the pollutants by BiPO4. Besides, calcination at 450 °C also induced the formation of oxygen defects in BiPO4, which promotes the separation of photogenerated charge carriers and thus improves the photocatalytic activity of BiPO4. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr02345a

  2. 210Po and 210Pb inhalation by cigarette smoking in Italy.

    PubMed

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

    2007-01-01

    210Po and its precursor 210Pb in cigarette smoke contribute a significant radiation dose to the lungs of smokers. In this work, the concentration of 210Po was determined in 17 of the most frequently smoked cigarette brands in Italy. Samples of tobacco, fresh filters, ash, and post-smoking filters were analyzed; 210Po was determined by alpha spectrometry after its spontaneous deposition on a silver disk. To verify the radioactive equilibrium between 210Po and 210Pb, lead was determined in one tobacco sample by counting the beta activity of its decay product 210Bi with a gas flow proportional detector after separation. The results of the present study show 210Po concentrations ranged from 6.84 to 17.49 mBq per cigarette. Based on these results, smokers who smoke 20 cigarettes per day inhale, on average, 79.53 +/- 28.65 mBq d(-1) of 210Po and 210Pb each. The mean value of the annual committed effective dose for Italian smokers, calculated by applying the dose conversion factor for adults of 4.3 microSv Bq(-1) for 210Po and 5.6 microSv Bq(-1) for 210Pb, was estimated to be 124.8 and 162.6 microSv y(-1) for 210Po and 210Pb, respectively. The lung dose from inhalation of cigarette smoke is much higher than the lung dose from inhalation of atmospheric 210Po and 210Pb. PMID:17164600

  3. {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.

  4. What Happens to LiMnPO4 upon Chemical Delithiation?

    PubMed

    Huang, Yiqing; Chernova, Natasha A; Yin, Qiyue; Wang, Qi; Quackenbush, Nicholas F; Leskes, Michal; Fang, Jin; Omenya, Fredrick; Zhang, Ruibo; Wahila, Matthew J; Piper, Louis F J; Zhou, Guangwen; Grey, Clare P; Whittingham, M Stanley

    2016-05-01

    Olivine MnPO4 is the delithiated phase of the lithium-ion-battery cathode (positive electrode) material LiMnPO4, which is formed at the end of charge. This phase is metastable under ambient conditions and can only be produced by delithiation of LiMnPO4. We have revealed the manganese dissolution phenomenon during chemical delithiation of LiMnPO4, which causes amorphization of olivine MnPO4. The properties of crystalline MnPO4 obtained from carbon-coated LiMnPO4 and of the amorphous product resulting from delithiation of pure LiMnPO4 were studied and compared. The phosphorus-rich amorphous phases in the latter are considered to be MnHP2O7 and MnH2P2O7 from NMR, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy analysis. The thermal stability of MnPO4 is significantly higher under high vacuum than at ambient condition, which is shown to be related to surface water removal. PMID:27065434

  5. Vitamins A, C, and E May Reduce Intestinal 210Po Levels after Ingestion.

    PubMed

    Kemp, Francis W; Portugal, Frank; Akudugu, John M; Neti, Prasad V S V; Ferraris, Ronaldo P; Howell, Roger W

    2016-07-01

    Damage to the gut mucosa is a probable contributory cause of death from ingested Po. Therefore, medical products are needed that can prevent, mitigate, and/or repair gastrointestinal (GI) damage caused by high-LET radiation emitted by Po. The present studies investigated the capacity of a diet highly enriched with vitamins A, C, and E (vitamin ACE) to protect against intestinal mucosal damage indicated by functional reductions in nutrient transport caused by orally ingested Po. Mice were gavaged with 0 or 18.5 kBq Po-citrate and fed a control or vitamin ACE-enriched diet (the latter beginning either 96 h before or immediately after gavage). Mouse intestines significantly retained Po on day 8 post-gavage. The concentration of Po in intestinal tissues was significantly (p<0.05) lower in all vitamin ACE groups compared to control. There were borderline significant Po-induced reductions in intestinal absorption of D-fructose. The combination of vitamins A, C, and E may reduce Po incorporation in the intestines when given before, or enhance decorporation when provided after, Po gavage. PMID:27218295

  6. 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

  7. 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.

  8. 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

  9. 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.

  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. 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

  13. 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

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. 76 FR 54931 - Post Office (PO) Box Fee Groups for Merged Locations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-06

    ... 111 Post Office (PO) Box Fee Groups for Merged Locations AGENCY: Postal Service TM . ACTION: Final..., Domestic Mail Manual (DMM ) 508.4 to allow Post Office Box TM (PO Box TM ) fee groups to be merged due to Post Office TM mergers and to have the ability to change a fee group more than one higher or...

  19. Draft Genome Sequence of Biocontrol Agent Pythium oligandrum Strain Po37, an Oomycota

    PubMed Central

    Berger, Harald; Yacoub, Amira; Gerbore, Jonathan; Grizard, Damien; Rey, Patrice; Sessitsch, Angela

    2016-01-01

    The oomycota Pythium oligandrum Po37 is used as a biocontrol agent of plant diseases. Here, we present the first draft of the P. oligandrum Po37 genome sequence, which comprises 725 scaffolds with a total length of 35.9 Mb and 11,695 predicted protein-coding genes. PMID:27081125

  20. 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... Indwelling blood oxygen partial pressure (PO2) analyzer. (a) Identification. An indwelling blood oxygen... electrode) and that is used to measure, in vivo, the partial pressure of oxygen in blood to aid...

  1. 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... Indwelling blood oxygen partial pressure (PO2) analyzer. (a) Identification. An indwelling blood oxygen... electrode) and that is used to measure, in vivo, the partial pressure of oxygen in blood to aid...

  2. 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... Indwelling blood oxygen partial pressure (PO2) analyzer. (a) Identification. An indwelling blood oxygen... electrode) and that is used to measure, in vivo, the partial pressure of oxygen in blood to aid...

  3. 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... Indwelling blood oxygen partial pressure (PO2) analyzer. (a) Identification. An indwelling blood oxygen... electrode) and that is used to measure, in vivo, the partial pressure of oxygen in blood to aid...

  4. 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... Indwelling blood oxygen partial pressure (PO2) analyzer. (a) Identification. An indwelling blood oxygen... electrode) and that is used to measure, in vivo, the partial pressure of oxygen in blood to aid...

  5. Draft Genome Sequence of Biocontrol Agent Pythium oligandrum Strain Po37, an Oomycota.

    PubMed

    Berger, Harald; Yacoub, Amira; Gerbore, Jonathan; Grizard, Damien; Rey, Patrice; Sessitsch, Angela; Compant, Stéphane

    2016-01-01

    The oomycotaPythium oligandrumPo37 is used as a biocontrol agent of plant diseases. Here, we present the first draft of theP. oligandrumPo37 genome sequence, which comprises 725 scaffolds with a total length of 35.9 Mb and 11,695 predicted protein-coding genes. PMID:27081125

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

    PubMed

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

    2014-03-17

    A new framework cobalt(II) hydroxyl phosphate, Co2PO4OH, was prepared by ionothermal synthesis using 1-butyl-4-methyl-pyridinium hexafluorophosphate as the ionic liquid. As the formation of Co2PO4F competes in the synthesis, the synthesis conditions have to be judiciously chosen to obtain well-crystallized, single phase Co2PO4OH. Single-crystal X-ray diffraction analyses reveal Co2PO4OH crystallizes with space group I41/amd (a = b = 5.2713(7) Å, c = 12.907(3) Å, V = 358.63(10) Å(3), and Z = 4). Astonishingly, it does not crystallize isotypically with Co2PO4F but rather isotypically with the hydroxyl minerals caminite Mg1.33[SO4(OH)0.66(H2O)0.33] and lipscombite Fe(2–y)PO4(OH) (0 ≤ y ≤ 2/3). Phosphate tetrahedra groups interconnect four rod-packed face-sharing ∞(1){CoO(6/2)} octahedra chains to form a three-dimensional framework structure. The compound Co2PO4OH was further characterized by powder X-ray diffraction, Fourier transform–infrared, and ultraviolet–visible spectroscopy, confirming the discussed structure. The magnetic measurement reveals that Co2PO4OH undergoes a magnetic transition and presents at low temperatures a canted antiferromagnetic spin order in the ground state. PMID:24597964

  7. GENE PROBE FOR PO MESSENGER RNA USED TO INDEX ACRYLAMIDE TOXIC NEUROPATHY IN RATS

    EPA Science Inventory

    A gene probe for the PNS myelin glycoprotein PO (PO-mRNA) was used to monitor acrylamide neuropathy in Sprague Dawley rats prior to, concurrent with, and subsequent to, ultrastructurally and immunocytochemically defined nerve damage. ats were dosed every other day with acrylamide...

  8. Rate-dependent, Li-ion insertion/deinsertion behavior of LiFePO4 cathodes in commercial 18650 LiFePO4 cells.

    PubMed

    Liu, Qi; He, Hao; Li, Zhe-Fei; Liu, Yadong; Ren, Yang; Lu, Wenquan; Lu, Jun; Stach, Eric A; Xie, Jian

    2014-03-12

    We have performed operando synchrotron high-energy X-ray diffraction (XRD) to obtain nonintrusive, real-time monitoring of the dynamic chemical and structural changes in commercial 18650 LiFePO4/C cells under realistic cycling conditions. The results indicate a nonequilibrium lithium insertion and extraction in the LiFePO4 cathode, with neither the LiFePO4 phase nor the FePO4 phase maintaining a static composition during lithium insertion/extraction. On the basis of our observations, we propose that the LiFePO4 cathode simultaneously experiences both a two-phase reaction mechanism and a dual-phase solid-solution reaction mechanism over the entire range of the flat voltage plateau, with this dual-phase solid-solution behavior being strongly dependent on charge/discharge rates. The proposed dual-phase solid-solution mechanism may explain the remarkable rate capability of LiFePO4 in commercial cells. PMID:24521163

  9. Electrochemical performance of NiO-doped LiFePO4/C cathode materials prepared from amorphous FePO4 · xH2O

    NASA Astrophysics Data System (ADS)

    Mahmud, Iqbal; Kim, Dong-Seob; Ur, Soon-Chul

    2016-05-01

    LiFePO4/C composites are prepared from amorphous FePO4 · xH2O and are modified with NiO (0.0, 0.01, 0.02, 0.03, and 0.04 mol) by using a solid-state reaction process with a spex milling system. The crystalline structure and the morphology of synthesized powders have been characterized by using X-ray diffraction (XRD) and scanning electron microscope (SEM). The XRD patterns indicate a complete solid solution for all the NiO-doped LiFePO4/C composites. The SEM images show that the sizes of the particles produced are distributed in the range of 200 - 300 nm. The electrochemical performances have been evaluated by using an impedance measurement and a galvanostatic charge/discharge test. The initial properties and impedance measurement reveal different improvements for different amounts of NiO doping in LiFePO4/C. A maximum capacity of 158.8 mAh/g at 0.1 C has been achieved LiFePO4/C doped with NiO at 0.01 mol. The present work reveals that the newly processed composite of LiFePO4/C doped with a small amount of NiO may be a promising material for using in a lithium-ion battery.

  10. Study of the solid-liquid equilibria in the LiPO{sub 3}-Y(PO{sub 3}){sub 3} binary system

    SciTech Connect

    Jouini, Anis; Ferid, Mokhtar; Trabelsi-Ayadi, Malika

    2003-02-20

    The LiPO{sub 3}-Y(PO{sub 3}){sub 3} system has been studied for the first time. Microdifferential thermal analysis ({mu}-DTA), infrared spectroscopy (IR) and X-ray diffraction were used to investigate the liquidus and solidus relations. The only new compound observed within this system is LiY(PO{sub 3}){sub 4}, melting incongruently at 1104 K. An eutectic appears at 4{+-}1 mol% Y(PO{sub 3}){sub 3} at 933 K. LiY(PO{sub 3}){sub 4} crystallizes in the monoclinic system C{sub 2/c} with a unit cell: a=16.201(4) A, b=7.013(2) A, c=9.573(2) A, {beta}=125.589(9) deg. , Z=4 and V=884.5 A{sup 3}, which is isostructural to LiNd(PO{sub 3}){sub 4}. The infrared absorption spectrum indicates that this salt is a chain polyphosphate.

  11. 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.

  12. 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.

  13. 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}

  14. Ultrathin carbon nanopainting of LiFePO4 by oxidative surface polymerization of dopamine

    NASA Astrophysics Data System (ADS)

    Ding, Bo; Tang, Wei Chin; Ji, Ge; Ma, Yue; Xiao, Pengfei; Lu, Li; Lee, Jim Yang

    2014-11-01

    The common strategy to address the low electronic conductivity of LiFePO4 is to downsize LiFePO4 and to coat the nanocrystal with conductive carbon film. The major issues with existing carbon coating techniques are thickness and quality control. This paper reports a facile carbon coating method which can provide ultrathin, uniform and fully encapsulating carbon coating on LiFePO4. This coating method capitalizes on the redox chemistry of surface Fe3+ on solvothermally synthesized LiFePO4 nanocrystal, to deposit uniform thin films of polydopamine films. The polymer film is easily carbonized into ultrathin carbon film. The carbon coated LiFePO4 exhibits very high rate performance (143 mAh g-1 at current density of 1700 mA g-1) with excellent capacity retention.

  15. Nucleation and growth of new particles in Po Valley, Italy

    NASA Astrophysics Data System (ADS)

    Hamed, A.; Joutsensaari, J.; Mikkonen, S.; Sogacheva, L.; Dal Maso, M.; Kulmala, M.; Cavalli, F.; Fuzzi, S.; Facchini, M. C.; Decesari, S.; Mircea, M.; Lehtinen, K. E. J.; Laaksonen, A.

    2007-01-01

    Aerosol number distribution measurements are reported at San Pietro Capofiume (SPC) station (44°39' N, 11°37' E) for the time period 2002-2005. The station is located in Po Valley, the largest industrial, trading and agricultural area in Italy with a high population density. New particle formation was studied based on observations of the particle size distribution, meteorological and gas phase parameters. The nucleation events were classified according to the event clarity based on the particle number concentrations, and the particle formation and growth rates. Out of a total of 769 operational days from 2002 to 2005 clear events were detected on 36% of the days whilst 33% are clearly non-event days. The event frequency was high during spring and summer months with maximum values in May and July, whereas lower frequency was observed in winter and autumn months. The average particle formation and growth rates were estimated as ~6 cm-3 s-1 and ~7 nm h-1, respectively. Such high growth and formation rates are typical for polluted areas. Temperature, wind speed, solar radiation, SO2 and O3 concentrations were on average higher on nucleation days than on non-event days, whereas relative and absolute humidity and NO2 concentration were lower; however, seasonal differences were observed. Backtrajectory analysis suggests that during majority of nucleation event days, the air masses originate from northern to eastern directions. We also study previously developed nucleation event correlations with environmental variables and show that they predict Po Valley nucleation events with variable success.

  16. Nucleation and growth of new particles in Po Valley, Italy

    NASA Astrophysics Data System (ADS)

    Hamed, A.; Joutsensaari, J.; Mikkonen, S.; Sogacheva, L.; Dal Maso, M.; Kulmala, M.; Cavalli, F.; Fuzzi, S.; Facchini, M. C.; Decesari, S.; Mircea, M.; Lehtinen, K. E. J.; Laaksonen, A.

    2006-10-01

    Aerosol number distribution measurements are reported at San Pietro Capofiume (SPC) station (44°39' N, 11°37' E) for the time period 2002-2005. The station is located in Po Valley, the largest industrial, trading and agricultural area in Italy with a high population density. New particle formation was studied based on observations of the particle size distribution, meteorological and gas phase parameters. The nucleation events were classified according to the event clarity based on the particle number concentrations, and the particle formation and growth rates. Out of a total of 769 operational days from 2002 to 2005 clear events were detected on 36% of the days whilst 33% are clearly non-event days. The event frequency was high during spring and summer months with maximum values in May and July, whereas lower frequency was observed in winter and autumn months. The average particle formation and growth rates were estimated as ~6 cm-3 s-1 and ~7 nm h-1, respectively. Such high growth and formation rates are typical for polluted areas. Temperature, wind speed, solar radiation, SO2 and O3 concentrations were on average higher on nucleation days than on non-event days, whereas relative and absolute humidity and NO2 concentration were lower; however, seasonal differences were observed. Backtrajectory analysis suggests that during majority of nucleation event days, the air masses originate from northern to eastern directions. We also study previously developed nucleation event correlations with environmental variables and show that they predict Po Valley nucleation events with variable success.

  17. 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.

  18. Adaptation of Nitrogen Fixation by Intact Soybean Nodules to Altered Rhizosphere pO21

    PubMed Central

    Criswell, Jerome G.; Havelka, Ulysses D.; Quebedeaux, Bruno; Hardy, Ralph W. F.

    1976-01-01

    The N2-fixing legume nodule requires O2 for ATP production; however, the O2 sensitivity of nitrogenase dictates a requirement for a low pO2 inside the nodule. The effects of long term exposures to various pO2s on N2[C2H2] fixation were evaluated with intact soybean (Glycine max [L.] Merr., var. Wye) plants. Continuous exposure of their rhizosphere to a pO2 of 0.06 atmospheres initially reduced nitrogenase activity by 37 to 45% with restoration of original activity in 4 to 24 hours and with no further change in tests up to 95 hours; continuous exposure to 0.02 atmosphere of O2 initially reduced nitrogenase activity 72%, with only partial recovery by 95 hours. Similar exposures to a pO2 of 0.32 atmospheres had little effect on N2[C2H2] fixation; a pO2 of 0.89 atmospheres initially reduced nitrogenase activity by 98% with restoration to only 14 to 24% of that of the ambient O2 controls by 95 hours. Re-exposure to ambient pO2 of plants adapted to nonambient pO2s reduced N2[C2H2] fixation to similar magnitudes as the reductions which occurred upon initial exposure to variant pO2 conditions, and a time period was required to readapt to ambient O2. It is concluded that the N2[C2H2]-fixing system of intact soybean plants is able to adapt to a wide range of external pO2s as probably occur in soil. We postulate that this occurs through an undefined mechanism which enables the nodule to maintain an internal pO2 optimal for nitrogenase activity. PMID:16659731

  19. Exploring the connection between 210Po and organic matter in the northwestern Mediterranean

    NASA Astrophysics Data System (ADS)

    Stewart, Gillian; Kirk Cochran, J.; Xue, Jianhong; Lee, Cindy; Wakeham, Stuart G.; Armstrong, Robert A.; Masqué, Pere; Carlos Miquel, Juan

    2007-03-01

    The disequilibrium between 210Po and its grandparent 210Pb has been proposed as a tracer of the vertical flux of sinking particulate organic matter in the ocean. The mechanism of association between 210Po and organic matter is, however, still unclear. To investigate this association we measured trace metals, minerals, organic carbon, nitrogen, and the natural radioisotopes 234Th, 228Th, 210Po, and 210Pb in sinking particles collected in sediment traps at 200 m in the northwestern Mediterranean. Pigments, fatty acids, and amino acids were used to identify the types and sources of particulate organic matter. Multivariate analyses were used to determine which components of sinking particulate matter are traced by 210Po and/or by the 210Po/ 210Pb ratio. Statistical analysis of the results indicates that the distribution of polonium in sinking marine particles is influenced by fresh phytoplankton-derived, nitrogen-rich organic matter as well as sulfur-containing amino acids. These findings are consistent with previous laboratory observations that the distribution of 210Po in biota parallels the distributions of both sulfur and protein, and indicate that these associations persist as material sinks through the water column. While this research generally supports the use of 210Po as a specific tracer of the flux of organic matter, the signals traced by 210Po/ 210Pb and 234Th/ 238U are not as distinct in the field as in laboratory experiments. Further work is needed to determine more precisely what 210Po/ 210Pb traces in order to increase the correspondence of 210Po/ 210Pb measurements to biogeochemically important rates and quantities.

  20. 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

  1. 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

  2. PO41, a snake venom metalloproteinase inhibitor isolated from Philander opossum serum.

    PubMed

    Jurgilas, Patrícia B; Neves-Ferreira, Ana G C; Domont, Gilberto B; Perales, Jonas

    2003-11-01

    PO41 was isolated from Philander opossum serum by DEAE-Sephacel, Phenyl Superose and Superdex 200 chromatographies and showed a molecular mass of 41,330 Da by MALDI-TOF MS. Molecular masses of 81.5 and 84.5 kDa were obtained by size exclusion chromatography and dynamic laser light scattering, respectively, suggesting that PO41 is dimeric. Its isoelectric point was estimated to be lower than 3.5. PO41 presented similar amino terminal sequence to those of DM40 and DM43, two antihaemorrhagins previously isolated from Didelphis marsupialis serum and was recognized by polyclonal antibodies raised against D. marsupialis antibothropic fraction. To study the inhibitory properties of this protein, the metalloproteinases bothrolysin and jararhagin were isolated from Bothrops jararaca venom by chromatographies on Superdex 200 and Phenyl Superose. Jararhagin was further submitted to a Mono Q column. The proteolytic and haemorrhagic effects of these haemorrhagins were neutralized by PO41. Both snake venom metalloproteinases formed stable complexes with PO41. The stoichiometry of the complex PO41-jararhagin was one inhibitor subunit to one molecule of the enzyme. These results show that PO41 has physicochemical, structural, immunoreactive and biological properties similar to other metalloproteinase inhibitors belonging to the supergene family of immunoglobulins. PMID:14602117

  3. 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.

  4. 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

  5. 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.

  6. BiPO4/reduced graphene oxide composites photocatalyst with high photocatalytic activity

    NASA Astrophysics Data System (ADS)

    Zhang, Yihe; Shen, Bo; Huang, Hongwei; He, Ying; Fei, Bin; Lv, Fengzhu

    2014-11-01

    The composite photocatalysts composed of BiPO4 and reduced graphene oxide (rGO) were synthesized by a facile hydrothermal method. Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), transmission electron spectroscopy (TEM), photoluminescence emission spectra (PL) and UV-vis diffuse reflection spectroscopy (DRS) were used to characterize the titled composites. The results showed that the BiPO4 particles can be immobilized on the surface of rGO sheets, and the crystallization phases of BiPO4 were significantly influenced by the amount of graphene. The phase transformation of BiPO4 crystal from hexagonal to monoclinic phase was observed. The introduction of rGO improved the optical properties of BiPO4 and thereby enhancing the utilization of light. Compared with pure BiPO4 under similar synthesis condition, the BiPO4/rGO composites exhibit a much higher photodegradation activity, which was confirmed by photoluminescence (PL) spectra and photocurrent (PC) generation.

  7. [Alpha-spectroscopic determination of 210Pb and 210PO in snow samples].

    PubMed

    Hashimoto, T; Masumura, S; Komatsu, S; Sotobayashi, T

    1982-09-01

    The concentrations of 210Pb and 210PO in several snow samples were determined using alpha-spectrometry. After 5 l of snow-melt water was subjected to coprecipitation of both nuclides with AlPO4, the solvent extraction procedure with TBP (tri-butyl phosphate)-isopropyl ether was applied to purify the polonium fraction, followed by the spontaneous electro-deposition on a Ni-sheet. The alpha-spectrum was measured with a Si(Au)-semiconductor detector coupled with a multichannel pulse-height analyzer. After the first determination of 210PO, the concentration of 210Pb was estimated from second measurement of 210PO grown newly from the remaining Pb-fraction during the storage period of more than 3 months. In these analytical procedures, 212Pb and 208PO tracers were conveniently utilized for the determination of collection yield for 210Pb and of the final chemical yield of 210PO, respectively. The contents of 210PO and 210Pb in the fresh snow were 3--30 mBq/l(81--810 fCi/l) and 250--720 mBq/l (6.8--19.5 pCi/l), respectively, and the residence time of 210Pb was given to be 6--12 days from the decay-growth relationships of both nuclides. PMID:7156418

  8. 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.

  9. 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.

  10. 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.

  11. Ultralong Lifespan and Ultrafast Li Storage: Single-Crystal LiFePO4 Nanomeshes.

    PubMed

    Zhang, Yan; Zhang, Hui Juan; Feng, Yang Yang; Fang, Ling; Wang, Yu

    2016-01-27

    A novel LiFePO4 material, in the shape of a nanomesh, has been rationally designed and synthesized based on the low crystal-mismatch strategy. The LiFePO4 nanomesh possesses several advantages in morphology and crystal structure, including a mesoporous structure, its crystal orientation that is along the [010] direction, and a shortened Li-ion diffusion path. These properties are favorable for their application as cathode in Li-ion batteries, as these will accelerate the Li-ion diffusion rate, improve the Li-ion exchange between the LiFePO4 nanomesh and the electrolyte, and reduce the Li-ion capacitive behavior during Li intercalation. So the LiFePO4 nanomesh exhibits a high specific capacity, enhanced rate capability, and strengthened cyclability. The method developed here can also be extended to other similar systems, for instance, LiMnPO4 , LiCoPO4 , and LiNiPO4 , and may find more applications in the designed synthesis of functional materials. PMID:26643716

  12. 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

    2015-01-01

    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

  13. 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

  14. 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.

  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. Morphology and conductivity study of solid electrolyte Li3PO4

    NASA Astrophysics Data System (ADS)

    Prayogi, Lugas Dwi; Faisal, Muhamad; Kartini, Evvy; Honggowiranto, Wagiyo; Supardi

    2016-02-01

    The comparison between two different methods of synthesize of solid electrolyte Li3PO4 as precursor material for developing lithium ion battery, has been performed. The first method is to synthesize Li3PO4 prepared by wet chemical reaction from LiOH and H3PO4 which provide facile, abundant available resource, low cost, and low toxicity. The second method is solid state reaction prepared by Li2CO3 and NH4H2PO4. In addition, the possible morphology identification of comparison between two different methods will also be discussed. The composition, morphology, and additional identification phase and another compound of Li3PO4 powder products from two different reaction are characterized by SEM, EDS, and EIS. The Li3PO4 powder produced from wet reaction and solid state reaction have an average diameter of 0.834 - 7.81 µm and 2.15 - 17.3 µm, respectively. The density of Li3PO4 prepared by wet chemical reaction is 2.238 gr/cm3, little bit lower than the sample prepared by solid state reaction which density is 2.3560 gr/cm3. The EIS measurement result shows that the conductivity of Li3PO4 is 1.7 x 10-9 S.cm-1 for wet chemical reaction and 1.8 x 10-10 S.cm-1 for solid state reaction. The conductivity of Li3PO4 is not quite different between those two samples even though they were prepared by different method of synthesize.

  17. Complex magnetism and magneto-transport of RECoPO (RE = La, Nd, and Sm)

    NASA Astrophysics Data System (ADS)

    Pal, Anand; Mehdi, Syed Sajjad; Husain, Mushahid; Gahtori, Bhasker; Awana, V. P. S.

    2011-11-01

    We report the electrical, magnetotransport, and specific heat of the layered polycrystalline RECoPO (RE = La, Nd, and Sm) samples. These compounds are iso-structural to recently discovered superconductor LaFeAs(O/F). Bulk polycrystalline samples are synthesized by a solid state reaction route in an evacuated sealed quartz tube. All these compounds are crystallized in a tetragonal structure with space group P4/nmm. Cobalt in these compounds is in an itinerant state, with its paramagnetic moment above 1.4 μB and the same orders ferromagnetically (FM) with saturation moment of around 0.20 μB below, say, 80 K. Though, LaCoPO shows single paramagnetic (PM) to ferromagnetic (FM) transition near 35 K, the NdCoPO and SmCoPO exhibit successive PM-FM-anti-ferromagnetic (AFM) transitions. Both FM and AFM transition temperatures vary with applied fields. Although the itinerant ferromagnetism occurs with small saturation moment, typical anti-ferromagnetic (AFM) transitions (TN1, TN2) are observed at 60 K and 14 K for Nd and 70 K and 40 K for Sm. This FM-AFM transition of Co spins in NdCoPO and SmCoPO is both field and temperature dependent. The magneto-transport of NdCoPO and SmCoPO distinctly follows their successive PM-FM-AFM transitions. It is clear that Sm/Nd (4f) interacts with the Co (3d) in first-time-synthesized Sm/NdCoPO.

  18. 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.

  19. Implementing DOIs for Oceanographic Satellite Data at PO.DAAC

    NASA Astrophysics Data System (ADS)

    Hausman, J.; Tauer, E.; Chung, N.; Chen, C.; Moroni, D. F.

    2013-12-01

    The Physical Oceanographic Distributed Active Archive Center (PO.DAAC) is NASA's archive for physical oceanographic satellite data. It distributes over 500 datasets from gravity, ocean wind, sea surface topography, sea ice, ocean currents, salinity, and sea surface temperature satellite missions. A dataset is a collection of granules/files that share the same mission/project, versioning, processing level, spatial, and temporal characteristics. The large number of datasets is partially due to the number of satellite missions, but mostly because a single satellite mission typically has multiple versions or even temporal and spatial resolutions of data. As a result, a user might mistake one dataset for a different dataset from the same satellite mission. Due to the PO.DAAC'S vast variety and volume of data and growing requirements to report dataset usage, it has begun implementing DOIs for the datasets it archives and distributes. However, this was not as simple as registering a name for a DOI and providing a URL. Before implementing DOIs multiple questions needed to be answered. What are the sponsor and end-user expectations regarding DOIs? At what level does a DOI get assigned (dataset, file/granule)? Do all data get a DOI, or only selected data? How do we create a DOI? How do we create landing pages and manage them? What changes need to be made to the data archive, life cycle policy and web portal to accommodate DOIs? What if the data also exists at another archive and a DOI already exists? How is a DOI included if the data were obtained via a subsetting tool? How does a researcher or author provide a unique, definitive reference (standard citation) for a given dataset? This presentation will discuss how these questions were answered through changes in policy, process, and system design. Implementing DOIs is not a trivial undertaking, but as DOIs are rapidly becoming the de facto approach, it is worth the effort. Researchers have historically referenced the source

  20. 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

  1. 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.

  2. Effect of conductive additives in LiFePO4 cathode for lithium-ion batteries

    SciTech Connect

    Shim, J.; Guerfi, A.; Zaghib, K.; Striebel, K.A.

    2003-11-25

    The electrochemical properties of LiFePO4 cathodes with different carbon contents were studied to find out the role of carbon as conductive additive. LiFePO4 cathodes containing from 0 percent to 12 percent of conductive additive (carbon black or mixture of carbon black and graphite) were cycled at different C rates. The capacity of LiFePO4 cathode increased, as conductive additive content increased. Carbon increased the utilization of active material and the electrical conductivity of electrode, but decreased volumetric capacity of electrode.

  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. Structure and performance of LiFePO4 cathode materials: A review

    NASA Astrophysics Data System (ADS)

    Zhang, Wei-Jun

    2011-03-01

    LiFePO4 has been considered a promising battery material in electric vehicles. However, there are still a number of technical challenges to overcome before its wide-spread applications. In this article, the structure and electrochemical performance of LiFePO4 are reviewed in light of the major technical requirements for EV batteries. The rate capability, capacity density, cyclic life and low-temperature performance of various LiFePO4 materials are described. The major factors affecting these properties are discussed, which include particle size, doping, carbon coating, conductive carbon loading and synthesis techniques. Important future research for science and engineering is suggested.

  5. 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

  6. [100]-Oriented LiFePO4 Nanoflakes toward High Rate Li-Ion Battery Cathode.

    PubMed

    Li, Zhaojin; Peng, Zhenzhen; Zhang, Hui; Hu, Tao; Hu, Minmin; Zhu, Kongjun; Wang, Xiaohui

    2016-01-13

    [100] is believed to be a tough diffusion direction for Li(+) in LiFePO4, leading to the belief that the rate performance of [100]-oriented LiFePO4 is poor. Here we report the fabrication of 12 nm-thick [100]-oriented LiFePO4 nanoflakes by a simple one-pot solvothermal method. The nanoflakes exhibit unexpectedly excellent electrochemical performance, in stark contrast to what was previously believed. Such an exceptional result is attributed to a decreased thermodynamic transformation barrier height (Δμb) associated with increased active population. PMID:26694590

  7. 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

  8. Research Update: Retardation and acceleration of phase separation evaluated from observation of imbalance between structure and valence in LiFePO{sub 4}/FePO{sub 4} electrode

    SciTech Connect

    Tokuda, Kazuya; Kawaguchi, Tomoya; Ichitsubo, Tetsu; Matsubara, Eiichiro; Fukuda, Katsutoshi

    2014-07-01

    LiFePO{sub 4} is a potential positive electrode material for lithium ion batteries. We have experimentally observed an imbalance between the valence change of Fe ions and the structure change from the LiFePO{sub 4} phase to the FePO{sub 4} phase during delithiation by simultaneous in situ XRD and XANES measurements in an LiFePO{sub 4}/FePO{sub 4} electrode. The ratio of structure change to valence change clearly indicates that the phase separation from LiFePO{sub 4} to FePO{sub 4} is suppressed at the beginning of delithiation, while it is accelerated at the latter stage, which is due to the coherent strain caused by the lattice misfit between the two phases.

  9. Electrochemical performance of patterned LiFePO4 nano-electrode with a pristine amorphous layer

    NASA Astrophysics Data System (ADS)

    Wang, Mao; Zhang, Wei; Liu, Yihang; Yang, Yong; Wang, Chunsheng; Wang, Yuan

    2014-04-01

    A patterned LiFePO4 nanorod with a pristine amorphous LiFePO4 surface layer was fabricated by controlling the temperature gradient from the interior to the exterior layer in high-temperature annealing process through designing hierarchical multilayer electrode structure. The three dimensional patterned LiFePO4 nanorods were prepared using tobacco mosaic virus nanoforest arrays. The results indicate that the nano-electrodes nearly reached the theoretical capacity at a very low C rate even without conductive coatings. The amorphous LiFePO4 can fast transport the Li-ion to inside crystal LiFePO4, thus enhancing the rate capability.

  10. 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.

  11. Magnetic structure and magnetocalorics of GdPO4

    DOE PAGESBeta

    Palacios, E; Rodr´ıguez-Velamaz´an,,; Evangelisti, Marco; McIntyre, G; Lorusso, G; Visser, Dirk; De Jongh, L. Jos; Boatner, Lynn A

    2014-01-01

    The magnetic ordering structure of GdPO4 is determined at T = 60 mK by diffraction of hot neutrons with wavelength = 0.4696 A. It corresponds to a non-collinear antiferromagnetic arrangement of the Gd moments with propagation vector k = (1/2, 0, 1/2). This arrangement is found to minimize the dipole-dipole interaction and the crystal field anisotropy energy, the magnetic superexchange being much smaller. The intensity of the magnetic reflections decreases with increasing temperature and vanishes at T 0.8 K, in agreement with the magnetic ordering temperature TN = 0.77 K, as reported in previous works based on heat capacity andmore » magnetic susceptibility measurements. The magnetocaloric parameters have been determined from heat capacity data at constant applied fields up to 7 T, as well as from isothermal magnetization data. The magnetocaloric effect reaches ST = 375.8 mJ cm3 K 1 at T = 2.1 K, largely exceeding the maximum values reported to date for Gd-based magnetic refrigerants.« less

  12. Magnetic structure and magnetocalorics of GdPO4

    SciTech Connect

    Palacios, E; Rodr´ıguez-Velamaz´an,,; Evangelisti, Marco; McIntyre, G; Lorusso, G; Visser, Dirk; De Jongh, L. Jos; Boatner, Lynn A

    2014-01-01

    The magnetic ordering structure of GdPO4 is determined at T = 60 mK by diffraction of hot neutrons with wavelength = 0.4696 A. It corresponds to a non-collinear antiferromagnetic arrangement of the Gd moments with propagation vector k = (1/2, 0, 1/2). This arrangement is found to minimize the dipole-dipole interaction and the crystal field anisotropy energy, the magnetic superexchange being much smaller. The intensity of the magnetic reflections decreases with increasing temperature and vanishes at T 0.8 K, in agreement with the magnetic ordering temperature TN = 0.77 K, as reported in previous works based on heat capacity and magnetic susceptibility measurements. The magnetocaloric parameters have been determined from heat capacity data at constant applied fields up to 7 T, as well as from isothermal magnetization data. The magnetocaloric effect reaches ST = 375.8 mJ cm3 K 1 at T = 2.1 K, largely exceeding the maximum values reported to date for Gd-based magnetic refrigerants.

  13. Hygroscopic growth of aerosol particles in the Po Valley

    NASA Astrophysics Data System (ADS)

    Svenningsson, I. B.; Hansson, H.-C.; Wiedensohler, A.; Ogren, J. A.; Noone, K. J.; Hallberg, A.

    1992-11-01

    A Tandem Differential Mobility Analyser (TDMA) was used to study the hygroscopic growth of individual ambient aerosol particles in the Po Valley, Italy. The measurements were made during the GCE fog experiment in November 1989. During fog, the interstitial aerosol (Dp(at ambient relative humidity)<5µm) was sampled. Two modes of particles with different hygroscopic growth were found for 0.030µm

  14. Avoided ferromagnetic quantum critical point in CeRuPO

    NASA Astrophysics Data System (ADS)

    Lengyel, E.; Macovei, M. E.; Jesche, A.; Krellner, C.; Geibel, C.; Nicklas, M.

    2015-01-01

    CeRuPO is a rare example of a ferromagnetic (FM) Kondo-lattice system. External pressure suppresses the ordering temperature to zero at about pc≈3 GPa. Our ac-susceptibility and electrical-resistivity investigations evidence that the type of magnetic ordering changes from FM to antiferromagnetic (AFM) at about p*≈0.87 GPa . Studies in applied magnetic fields suggest that ferromagnetic and antiferromagnetic correlations compete for the ground state at p >p* , but finally the AFM correlations win. The change in the magnetic ground-state properties is closely related to the pressure evolution of the crystalline-electric-field level scheme and the magnetic Ruderman-Kittel-Kasuya-Yosida exchange interaction. The Néel temperature disappears abruptly in a first-order-like fashion at pc, hinting at the absence of a quantum critical point. This is consistent with the low-temperature transport properties exhibiting Landau-Fermi-liquid behavior in the whole investigated pressure range up to 7.5 GPa.

  15. 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

  16. 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.

  17. Molecular cloning, structure and expressional profiles of two novel single-exon genes (PoCCR6A and PoCCR6B) in the Japanese flounder (Paralichthys olivaceus).

    PubMed

    Wang, Lei; Zhang, Yong-zhen; Xu, Wen-teng; Jia, Xiao-dong; Chen, Song-lin

    2016-05-01

    CCR6 is an important binding receptor of CCL20 and beta-defensins, and has multiple functions in the innate and acquired immune responses. In this study, we cloned the PoCCR6A and PoCCR6B genes of the Japanese flounder and studied the gene structure and expression patterns of these two genes in bacterial infection. The full-length PoCCR6A cDNA is 1415 bp and the open reading frame (ORF) is 1113 bp, encoding a 370-amino-acid peptide. The full-length PoCCR6B cDNA is 2193 bp and the ORF is 1029 bp, encoding a 363-amino-acid peptide. The structures of PoCCR6A and PoCCR6B indicate that they are single-exon genes. The predicted proteins encoded by PoCCR6A and PoCCR6B have the typical G-protein-coupled receptor (GPCR) family signature of seven transmembrane domains and several conserved structural features. A tissue distribution analysis showed that PoCCR6A is predominately expressed in the intestine, gill, and blood, and PoCCR6B in the gill, spleen, and liver. The expression patterns of the two chemokine receptors were analyzed during bacterial infection. In spleen and kidney, the expression of PoCCR6A was significantly upregulated at 24 h after infection, whereas the expression of PoCCR6B was steady at these time points. While in intestine, both of them were upregulated at 6 h-12 h after infection, and in gill the expression levels of them were upregulated at 24 h. The patterns of expression suggested that PoCCR6A and PoCCR6B play an important role in the immune response of the Japanese flounder, especially in the mucosal tissues. PMID:26997201

  18. The Solar Terrestrial Relations Observatory (STEREO) Education and Outreach (E/PO) Program

    NASA Astrophysics Data System (ADS)

    Peticolas, L. M.; Craig, N.; Kucera, T.; Michels, D. J.; Gerulskis, J.; MacDowall, R. J.; Beisser, K.; Chrissotimos, C.; Luhmann, J. G.; Galvin, A. B.; Ratta, L.; Drobnes, E.; Méndez, B. J.; Hill, S.; Marren, K.; Howard, R.

    2008-04-01

    The STEREO mission’s Education and Outreach (E/PO) program began early enough its team benefited from many lessons learned as NASA’s E/PO profession matured. Originally made up of discrete programs, by launch the STEREO E/PO program had developed into a quality suite containing all the program elements now considered standard: education workshops, teacher/student guides, national and international collaboration, etc. The benefit of bringing so many unique programs together is the resulting diverse portfolio, with scientists, E/PO professionals, and their education partners all of whom can focus on excellent smaller programs. The drawback is a less cohesive program nearly impossible to evaluate in its entirety with the given funding. When individual components were evaluated, we found our programs mostly made positive impact. In this paper, we elaborate on the programs, hoping that others will effectively use or improve upon them. When possible, we indicate the programs’ effects on their target audiences.

  19. 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.

  20. Probing the failure mechanism of nanoscale LiFePO4 for Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Gu, Meng; Shi, Wei; Zheng, Jianming; Yan, Pengfei; Zhang, Ji-guang; Wang, Chongmin

    2015-05-01

    LiFePO4 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 LiFePO4 materials. We found that upon prolonged electrochemical cycling of the battery, the LiFePO4 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 LiFePO4 cathode for high-energy and high-power rechargeable battery for electric transportation.

  1. 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

  2. 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%.

  3. 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.

  4. Sol-precipitation-hydrothermal synthesis and luminescence of GdPO4:Tb3+ submicron cubes

    NASA Astrophysics Data System (ADS)

    Cao, Yanyan; Sun, Peng; Liang, Yingmin; Wang, Rongrong; Zhang, Xiao

    2016-05-01

    GdPO4:Tb3+ submicron cubes were synthesized by a sol-precipitation-hydrothermal process. The XRD result indicated that GdPO4:Tb3+ submicron cubes have pure hexagonal phase. The SEM and TEM images confirmed the formation of cubic morphology. Under the excitation at 273 nm, GdPO4:Tb3+ submicron cubes show emission bands corresponding to Gd3+ and Tb3+. With the increasing Tb3+ concentration, the emission intensities originating from Gd3+ and 5D3 → 7Fj transition of Tb3+ decrease, but the emission intensities originating from 5D4 → 7Fj transition of Tb3+ increase. These results suggested energy transfer from Gd3+ to Tb3+ and the occurrence of cross-relaxation processes in GdPO4:Tb3+ submicron cubes.

  5. 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.

  6. 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.

  7. The iron phosphate CaFe3(PO4)3O

    PubMed Central

    Hidouri, Mourad; Ben Amara, Mongi

    2009-01-01

    A new iron phosphate, calcium triiron(III) tris­(phosphate) oxide, CaFe3(PO4)3O, has been isolated and shown to exhibit a three-dimensional structure built by FeO6 octa­hedra, FeO5 trigonal bipyramids and PO4 tetra­hedra. The FeOx (x = 5, 6) polyhedra are linked through common corners and edges, forming [Fe6O28]∞ chains with branches running along [010]. Adjacent chains are connected by the phosphate groups via common corners and edges, giving rise to a three-dimensional framework analogous to those of the previously reported SrFe3(PO4)3O and Bi0.4Fe3(PO4)3O structures, in which the Ca2+ cations occupy a single symmetry non-equivalent cavity. PMID:21583300

  8. The iron phosphate CaFe(3)(PO(4))(3)O.

    PubMed

    Hidouri, Mourad; Ben Amara, Mongi

    2009-01-01

    A new iron phosphate, calcium triiron(III) tris-(phosphate) oxide, CaFe(3)(PO(4))(3)O, has been isolated and shown to exhibit a three-dimensional structure built by FeO(6) octa-hedra, FeO(5) trigonal bipyramids and PO(4) tetra-hedra. The FeO(x) (x = 5, 6) polyhedra are linked through common corners and edges, forming [Fe(6)O(28)](∞) chains with branches running along [010]. Adjacent chains are connected by the phosphate groups via common corners and edges, giving rise to a three-dimensional framework analogous to those of the previously reported SrFe(3)(PO(4))(3)O and Bi(0.4)Fe(3)(PO(4))(3)O structures, in which the Ca(2+) cations occupy a single symmetry non-equivalent cavity. PMID:21583300

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. Levels and transfer of 210Po and 210Pb in Nordic terrestrial ecosystems.

    PubMed

    Brown, J E; Gjelsvik, R; Roos, P; Kålås, J A; Outola, I; Holm, E

    2011-05-01

    Recent developments regarding environmental impact assessment methodologies for radioactivity have precipitated the need for information on levels of naturally occurring radionuclides within and transfer to wild flora and fauna. The objectives of this study were therefore to determine activity concentrations of the main dose forming radionuclides (210)Po and (210)Pb in biota from terrestrial ecosystems thus providing insight into the behaviour of these radioisotopes. Samples of soil, plants and animals were collected at Dovrefjell, Central Norway and Olkiluoto, Finland. Soil profiles from Dovrefjell exhibited an approximately exponential fall in (210)Pb activity concentrations from elevated levels in humus/surface soils to "supported" levels at depth. Activity concentrations of (210)Po in fauna (invertebrates, mammals, birds) ranged between 2 and 123 Bq kg(-1)d.w. and in plants and lichens between 20 and 138 Bq kg(-1)d.w. The results showed that soil humus is an important reservoir for (210)Po and (210)Pb and that fauna in close contact with this media may also exhibit elevated levels of (210)Po. Concentration ratios appear to have limited applicability with regards to prediction of activity concentrations of (210)Po in invertebrates and vertebrates. Biokinetic models may provide a tool to explore in a more mechanistic way the behaviour of (210)Po in this system. PMID:20650552

  15. Optimization of LiFePO4 nanoparticle suspensions with polyethyleneimine for aqueous processing.

    PubMed

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

    2012-02-28

    Addition of dispersants to aqueous based lithium-ion battery electrode formulations containing LiFePO(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(4) active cathode material. The isoelectric point, a key parameter in characterizing colloidal dispersion stability, of LiFePO(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(4) and super P C45 suspension, respectively. LiFePO(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(4) performance. PMID:22292836

  16. Phase dependent structural and electronic properties of lanthanum orthophosphate (LaPO4)

    NASA Astrophysics Data System (ADS)

    Neupane, M. R.; Garrett, G. A.; Rudin, S.; Andzelm, J. W.

    2016-05-01

    We study the phase-dependent structural and electronic properties of bulk LaPO4, using density functional theory (DFT). The applicability of conventional semi-local and hybrid functionals in predicting structural and electronic properties of monoclinic and hexagonal LaPO4 is evaluated by comparing results to available experimental data. The monoclinic LaPO4 was found to be more stable than the hexagonal phase in ambient conditions with a small energy difference, suggesting a possibility of a phase transition. Both the phases in the bulk form are found to be diamagnetic with indirect energy gaps. These results are consistent with available experimental results. In the monoclinic phase, the hybrid functionals predict indirect band gap at about 8 eV. Furthermore, the calculated indirect–direct transition energy offset (ΔE) in the hexagonal phase was three times lower than the monoclinic phase. Our calculations based on hybrid functionals also reveal that the states near the conduction band edge in the hexagonal LaPO4 are strongly hybridized between La and PO4 states. By analyzing the band dispersion around the band edges, we show that the hexagonal phase has lighter electron effective mass, as compared to the monoclinic phase. With a larger energy gap, smaller ΔE, and smaller electron effective mass, the hexagonal LaPO4 might be a promising candidate material as an n-type transparent oxide.

  17. The Electronic Spectrum of H_2PO, the Prototypical Phosphoryl Free Radical

    NASA Astrophysics Data System (ADS)

    Gharaibeh, Mohammed A.; Clouthier, Dennis J.

    2011-06-01

    The electronic spectrum of the H_2PO radical has been identified by laser-induced fluorescence (LIF) and single vibronic level (SVL) emission techniques. The radical was produced in a pulsed electric discharge jet using a precursor mixture of phosphine (PH_3) and carbon dioxide in high-pressure argon and the tilde{B}^2A' - tilde{X}^2A' electronic transition was detected in the 410-338 nm region. Low resolution LIF and SVL emission spectra of H_2PO and D_2PO have been recorded and the A' vibrational frequencies have been determined in both states. High-resolution spectra of the 0_0^0 bands of H_2PO and D_2PO, which consist of strong a-type and weaker c-type components, were recorded. The spectra have been rotationally analyzed and the excited state molecular structure determined. The spectrum of H_2PO will be discussed in comparison with the spectra of other phosphoryl and arsenyl radicals that have been recently studied in our laboratory.

  18. 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.

  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. 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

  1. 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.

  2. IR near-field spectroscopy and imaging of single Li(x)FePO4 microcrystals.

    PubMed

    Lucas, I T; McLeod, A S; Syzdek, J S; Middlemiss, D S; Grey, C P; Basov, D N; Kostecki, R

    2015-01-14

    This study demonstrates the unique capability of infrared near-field nanoscopy combined with Fourier transform infrared spectroscopy to map phase distributions in microcrystals of Li(x)FePO4, a positive electrode material for Li-ion batteries. Ex situ nanoscale IR imaging provides direct evidence for the coexistence of LiFePO4 and FePO4 phases in partially delithiated single-crystal microparticles. A quantitative three-dimensional tomographic reconstruction of the phase distribution within a single microcrystal provides new insights into the phase transformation and/or relaxation mechanism, revealing a FePO4 shell surrounding a diamond-shaped LiFePO4 inner core, gradually shrinking in size and vanishing upon delithiation of the crystal. The observed phase propagation pattern supports recent functional models of LiFePO4 operation relating electrochemical performance to material design. This work demonstrates the remarkable potential of near-field optical techniques for the characterization of electrochemical materials and interfaces. PMID:25375874

  3. 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

  4. Phase dependent structural and electronic properties of lanthanum orthophosphate (LaPO4).

    PubMed

    Neupane, M R; Garrett, G A; Rudin, S; Andzelm, J W

    2016-05-25

    We study the phase-dependent structural and electronic properties of bulk LaPO4, using density functional theory (DFT). The applicability of conventional semi-local and hybrid functionals in predicting structural and electronic properties of monoclinic and hexagonal LaPO4 is evaluated by comparing results to available experimental data. The monoclinic LaPO4 was found to be more stable than the hexagonal phase in ambient conditions with a small energy difference, suggesting a possibility of a phase transition. Both the phases in the bulk form are found to be diamagnetic with indirect energy gaps. These results are consistent with available experimental results. In the monoclinic phase, the hybrid functionals predict indirect band gap at about 8 eV. Furthermore, the calculated indirect-direct transition energy offset (ΔE) in the hexagonal phase was three times lower than the monoclinic phase. Our calculations based on hybrid functionals also reveal that the states near the conduction band edge in the hexagonal LaPO4 are strongly hybridized between La and PO4 states. By analyzing the band dispersion around the band edges, we show that the hexagonal phase has lighter electron effective mass, as compared to the monoclinic phase. With a larger energy gap, smaller ΔE, and smaller electron effective mass, the hexagonal LaPO4 might be a promising candidate material as an n-type transparent oxide. PMID:27114454

  5. Polytypism in wagnerite, Mg2PO4(F,OH)

    NASA Astrophysics Data System (ADS)

    Chopin, C.; Armbruster, T.; Leyx, C.

    2003-04-01

    The Mg, Fe and Mn phosphates with formula Me2+_2PO_4(F,OH) belong to two groups which share the same fundamental monoclinic structure type, but in one of which the b parameter is doubled. Specifically, magniotriplite (Mg), zwieselite (Fe) and triplite (Mn) are F-dominant and have space group I2/a, with Z = 8, b_0 ≈ 6.5 Å, whereas wagnerite (Mg, F dominant), wolfeite (Fe, OH dominant) and triploidite (Mn, OH dominant) have space group P2_1/a, Z = 16 and b = 2 b_0 ≈ 13 Å. In I2/a magniotriplite, eight F atoms are distributed over two eightfold equipoints with 50% occupancy. Periodic ordering of the F atoms into each of these equipoint positions (say A and B), each alternately void and fully occupied along b, leads to a new, double cell with space group P2_1/a and a 2b_0 parameter, i.e. the wagnerite cell, in which the succession of the occupied F positions along b is ABAB (Tadini 1981). Ren et al. (2002) reported from granulite-facies rocks of East Antarctica a wagnerite "polymorph" structurally very close to wagnerite, but with space group Ia, b = 5b_0 ≈ 32 Å and Z = 40. We studied wagnerite crystals from granulite-facies rocks of central Australia (Vry and Cartwright 1994). CCD area-detector imaging revealed either 7b_0 ≈ 45 Å or 9b_0 ≈ 57 Å superstructures (Z = 56 and 72, respectively). The structure of the 9b_0 phase was refined in space group Ia to R = 6% from 11903 unique reflections. We show that wagnerite and the 5b_0, 7b_0 and 9b_0 phases share the same topological arrangement of cations and oxygen atoms, differ only by the periodic faulting of the A-B succession of the F atoms along b, and are all members of a polytypic series based on the magniotriplite cell (b_0). The relevant polytypes and F ordering schemes are wagnerite-a2bc (AB), wagnerite-a5bc (ABAAB), wagnerite-a7bc (ABAABAB) and wagnerite-a9bc (ABAABABAB). Reinvestigation of OH-rich wagnerite from Miregn (Central Alps) and of OH-rich to OH-dominant wagnerite from Dora-Maira (W. Alps

  6. Synthesis and performances of 2LiFePO4·Li3V2(PO4)3/C cathode materials via spray drying method with double carbon sources

    NASA Astrophysics Data System (ADS)

    Zhang, Jia-feng; Shen, Chao; Zhang, Bao; Zheng, Jun-chao; Peng, Chun-li; Wang, Xiao-wei; Yuan, Xin-bo; Li, Hui; Chen, Guo-min

    2014-12-01

    The 2LiFePO4·Li3V2(PO4)3/C samples are synthesized through spray drying method. Glucose and oxalic acid are used as collaborative carbon sources to improve the electrochemical performance of 2LiFePO4·Li3V2(PO4)3/C composites. XRD results reveal the LiFePO4·Li3V2(PO4)3/C samples are composed of orthorhombic LiFePO4 and monoclinic Li3V2(PO4)3 phases. SEM results reveal that the nano-spherical Fe4(VO4)4·5H2O are about 80 nm and the 2LiFePO4·Li3V2(PO4)3/C composites possess a micro-nano spherical morphology with carbon coating layer. The samples show the best electrochemical performance when the mass ration of glucose and oxalic is 6:4, it can deliver a capacity of 147.6 mAh g-1, 145.0 mAh g-1, 134.1 mAh g-1 and 123.0 mAh g-1 at the rates of 0.1C, 1C, 5C and 10C, respectively.

  7. 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. PMID:24656403

  8. Solvothermal synthesis and photoluminescence properties of BiPO{sub 4} nano-cocoons and nanorods with different phases

    SciTech Connect

    Xue Fei; Li Haibo; Zhu Yongchun; Xiong Shenglin; Zhang Xianwen; Wang Tingting; Liang Xin; Qian Yitai

    2009-06-15

    Hexagonal phase BiPO{sub 4} nano-cocoons and monoclinic phase BiPO{sub 4} nanorods have been synthesized in the mixed solvents of glycerol and distilled water with the volume ratio of 2:1 at 200 deg. C. The solvothermal evolution process from hexagonal phase BiPO{sub 4} nano-cocoons to monoclinic phase BiPO{sub 4} nanorods was observed by varying the reaction time from 1 to 3 h. In the hydrothermal condition at 160 deg. C, the similar phase transformation from hexagonal phase BiPO{sub 4} to monoclinic phase BiPO{sub 4} was also observed, accompanying with a morphology transformation from nanorods to octahedron-like microcrystals. It was found that the volume ratio of glycerol to water in the solvothermal condition had a great impact on the shapes of products, while it had no influence on the formation of different phases. The fluorescence spectra of hexagonal phase BiPO{sub 4} nano-cocoons and monoclinic phase BiPO{sub 4} nanorods were also studied. - Graphical abstract: Hexagonal phase BiPO{sub 4} nano-cocoons were fabricated by solvothermal method at 200 deg. C for 1 h. When the reaction time was increased to 3 h, monoclinic phase BiPO{sub 4} nanorods were formed.

  9. 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.

  10. Enhancement of electrochemical behavior of nanostructured LiFePO4/Carbon cathode material with excess Li

    NASA Astrophysics Data System (ADS)

    Bazzi, K.; Nazri, M.; Naik, V. M.; Garg, V. K.; Oliveira, A. C.; Vaishnava, P. P.; Nazri, G. A.; Naik, R.

    2016-02-01

    We have synthesized carbon coated LiFePO4 (C-LiFePO4) and C-Li1.05FePO4 with 5 mol% excess Li via sol-gel method using oleic acid as a source of carbon for enhancing electronic conductivity and reducing the average particle size. Although the phase purity of the crystalline samples was confirmed by x-ray diffraction (XRD), the 57Fe Mössbauer spectroscopy analyses show the presence of ferric impurity phases in both stoichiometric and non-stoichiometric C-LiFePO4 samples. Transmission electron microscopy measurements show nanosized C-LiFePO4 particles uniformly covered with carbon, with average particle size reduced from ∼100 nm to ∼50 nm when excess lithium is used. Electrochemical measurements indicate a lower charge transfer resistance and better electrochemical performance for C-Li1.05FePO4 compared to that of C-LiFePO4. The aim of this work is to systematically analyze the nature of impurities formed during synthesis of LiFePO4 cathode material, and their impact on electrochemical performance. The correlation between the morphology, charge transfer resistance, diffusion coefficient and electrochemical performance of C-LiFePO4 and C- Li1.05FePO4 cathode materials are discussed.

  11. 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.

  12. Irreversible phase transition between LiFePO4 and FePO4 during high-rate charge-discharge reaction by operando X-ray diffraction

    NASA Astrophysics Data System (ADS)

    Takahashi, Ikuma; Mori, Takuya; Yoshinari, Takahiro; Orikasa, Yuki; Koyama, Yukinori; Murayama, Haruno; Fukuda, Katsutoshi; Hatano, Masaharu; Arai, Hajime; Uchimoto, Yoshiharu; Terai, Takayuki

    2016-03-01

    LiFePO4 is a practically used cathode material for lithium-ion batteries due to a high theoretical capacity, high cycle capability and the high-rate performance. The metastable LixFePO4 (LxFP) phase with an intermediate composition appears in the non-equilibrium state at high-rate condition. However, the formation process of the metastable LxFP phase and its impact to the electrochemical property are still unclear. In order to elucidate these points, we directly observed the phase transition behavior by applying operando XRD during 10C charge-discharge. LxFP phase does not form in charge reaction but preferentially forms in discharge reaction. The phase transition from LxFP to Li-rich phase is less likely to proceed in the end of discharge reaction. The asymmetric phase transition between LiFePO4 and FePO4 results in decreasing the discharge capacity and increasing the irreversible capacity at high-rate conditions.

  13. 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}.

  14. 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

  15. Concentration levels of 210Pb and 210Po in dry tobacco leaves in Greece.

    PubMed

    Savidou, A; Kehagia, K; Eleftheriadis, K

    2006-01-01

    Tobacco leaves are large and have sticky exudates that retain the radon decay products once they deposit on the leaves. The study of 210Po in tobacco is required, because of the cumulative alpha-radiation dose delivered to humans from inhaled 210Po in cigarette smoke. 210Pb is the other element of interest since it is the 210Po precursor in the radioactive decay chain. In the present study, the concentrations of these two radionuclides were determined in tobacco samples from seven regions in Greece. 210Po was determined by alpha spectrometry using a surface barrier detector after radiochemical separation and spontaneous deposition of polonium on a nickel disk. The 210Pb activity in the samples was determined via the 210Po resulting from the decay of 210Pb. The results of the present study indicate that 210Po concentrations ranged from 3.6 to 17.0 mBqg(-1) (average 13.1 mBqg(-1)) of dry tobacco, while 210Pb concentrations ranged from 7.3 to 18.0 mBqg(-1) (average 13.4 mBqg(-1)). The mean value of the annual committed effective dose for smokers (20 cigarettes per day) of Greek tobacco was estimated to be 287 microSv (124 microSv from 210Po and 163 microSv from 210Pb). The inhalation dose for smokers is on average about 12 times higher than for non-smokers living in the mid-latitudes of the northern hemisphere. PMID:16098642

  16. 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.

  17. Crystal structure and optical study of praseodymium polyphosphate Pr(PO{sub 3}){sub 3}

    SciTech Connect

    Jouini, Anis; Ferid, Mokhtar; Gacon, Jean-Claude; Grosvalet, Laurent; Thozet, Alain; Trabelsi-Ayadi, Malika

    2003-10-01

    Single crystals of praseodymium polyphosphate Pr(PO{sub 3}){sub 3} were grown for the first time using a flux method and characterized by single-crystal X-ray diffraction. Pr(PO{sub 3}){sub 3} is isostructural with Nd(PO{sub 3}){sub 3} and La(PO{sub 3}){sub 3}. It crystallizes in the orthorhombic system with space group C222{sub 1} (D{sub 2}{sup 5}), with lattice parameters: a=11.234(1) A, b=8.5289(8) A, c=7.3199(8) A. The crystal structure was resolved with final R(F{sup 2})=0.0359 and R{sub w}(F{sup 2})=0.0924 for 402 independent reflections (F{sub 0}{sup 2}{>=}2{sigma}(F{sub 0}{sup 2})). In the Pr(PO{sub 3}){sub 3} structure, oxygen atoms form a PO{sub 4} tetrahedron around each P atom and a PrO{sub 8} polyhedron around each Pr atom. The PO{sub 4} tetrahedra share corners to produce helical chains and the PrO{sub 8} polyhedra share edges to form zigzag chains. The shortest Pr-Pr distance is 4.253 A. The energies of the vibrational modes of the crystal are obtained from the infrared and Raman spectra. Measurements of emission spectra under pulsed laser excitation in the Pr{sup 3+} (4f{sup 2}) {sup 3}P{sub J} (J=0, 1, 2) levels and decay times of the observed emissions are reported both at room and liquid-helium temperatures. X-ray excitation leads to intense ultraviolet 4f{sup 1}5d{sup 1}{yields}4f{sup 2} band emissions in the 200-300 nm spectral range with decay times in the order of 6 ns both at room and low temperatures.

  18. 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

  19. 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

  20. Photonic bandgap guiding into a composite AgPO3-glass/silica microstructured optical fibre

    NASA Astrophysics Data System (ADS)

    Konidakis, Ioannis; Zito, Gianluigi; Pissadakis, Stavros

    2012-04-01

    Infiltration of glass matrices inside Photonic Crystals Fibres (PCFs) for achieving photonic bandgap (PBG) guidance and expand devices development capabilities has been recently demonstrated. Herein, we report the fabrication of an all-solid PBG guiding PCF by suction-assisted infiltration of molten silver-metaphosphate (AgPO3) glass into the air capillaries of a commercial solid core PCF. The relatively low viscosity of the AgPO3 glass melt permitted infiltration at ~ 700 °C inside an annealing oven apparatus by applying suction with the use of a standard mechanical vacuum pump, while its low glass transition temperature of ~ 190 °C allows structural relaxations at temperatures close to ambient and the formation of high quality glass strands inside the silica structure of the PCF. The AgPO3/silica PCF was characterized by means of its transmission spectrum that showed PBG guidance over the measurement range (350-1650nm). The effect of the AgPO3 glass photosensitivity on the guiding properties of the AgPO3/silica PCF was explored by employing a 355nm, 150 ps laser irradiation. The exposure gave rise to a photo-induced enhancement of the transmission-to-stop-band extinction ratio by ~60 dB/cm as well as bandwidth tuning. Numerical calculations of the transmission spectra of the AgPO3/silica PCF have been performed for confirming the experimental results and modelling the photo-induced variation of the two-glass fibre transmission. We believe that the fabrication of the AgPO3/silica PBG fibre constitutes a strong base for the development of new in-fibre sensing and scattering-based devices, by exploiting the high photosensitivity of silver and its specific plasmon absorption properties.

  1. 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

  2. Radiokinetic study on nucleation process of 65Zn(OH)2, 65Zn3(PO4)2 and 51CrPO4 crystals in gelatin and agar

    NASA Astrophysics Data System (ADS)

    Cecal, Al; Palamaru, M.; Chisca, S.; Balan, A.

    1999-01-01

    The nucleation process of 65Zn(OH)2, 65Zn3(PO4)2, and 51CrPO4 crystals in gelatin and agar was studied by using radioactive tracers. The diffusion rate, constants for 65Zn2+ and 51Cr3+ cations through gel, and the reaction rate constants of nucleation process as well as the beginning time of crystal appearance were established. It was found that the reaction rate constant of the low-soluble crystal is higher, and consequently, in a given colloidal medium this parameter varies as follows: k * Zn(PO4)2> k * Zn(OH) 2> k * CrPO 4

  3. Radiokinetic study on nucleation process of 65Zn(OH)2, 65Zn3(PO4)2 and 51CrPO4 crystals in gelatin and agar

    NASA Astrophysics Data System (ADS)

    Cecal, Al; Palamaru, M.; Chisca, S.; Balan, A.

    1999-01-01

    The nucleation process of 65Zn(OH)2, 65Zn3(PO4)2, and 51CrPO4 crystals in gelatin and agar was studied by using radioactive tracers. The diffusion rate, constants for 65Zn2+ and 51Cr3+ cations through gel, and the reaction rate constants of nucleation process as well as the beginning time of crystal appearance were established. It was found that the reaction rate constant of the low-soluble crystal is higher, and consequently, in a given colloidal medium this parameter varies as follows: k * Zn(PO4)2>k * Zn(OH) 2>k * CrPO 4

  4. Screening and analysis of PoAkirin1 and two related genes in response to immunological stimulants in the Japanese flounder (Paralichthys olivaceus)

    PubMed Central

    2013-01-01

    A member of the NF-κB signaling pathway, PoAkirin1, was cloned from a full-length cDNA library of Japanese flounder (Paralichthys olivaceus). The full-length cDNA comprises a 5′UTR of 202 bp, an open reading frame of 564 bp encoding a 187-amino-acid polypeptide and a 521-bp 3′UTR with a poly (A) tail. The putative protein has a predicted molecular mass of 21 kDa and an isoelectric point (pI) of 9.22. Amino acid sequence alignments showed that PoAkirin1 was 99% identical to the Scophthalmus maximus Akirin protein (ADK27484). Yeast two-hybrid assays identified two proteins that interact with PoAkirin1: PoHEPN and PoC1q. The cDNA sequences of PoHEPN and PoC1q are 672 bp and 528 bp, respectively. Real-time quantitative reverse-transcriptase polymerase chain reaction analysis showed that bacteria could induce the expressions of PoAkirin1, PoHEPN and PoC1q. However, the responses of PoHEPN and PoC1q to the bacterial challenge were slower than that of PoAkirin1. To further study the function of PoAkirin1, recombinant PoAkirin1 and PoHEPN were expressed in Escherichia coli and would be used to verify the PoAkirin1-PoHEPN binding activity. These results identified two proteins that potentially interact with PoAkirin1 and that bacteria could induce their expression. PMID:23651673

  5. Screening and analysis of PoAkirin1 and two related genes in response to immunological stimulants in the Japanese flounder (Paralichthys olivaceus).

    PubMed

    Yang, Chang-Geng; Wang, Xian-Li; Zhang, Bo; Sun, Bing; Liu, Shan-Shan; Chen, Song-Lin

    2013-01-01

    A member of the NF-κB signaling pathway, PoAkirin1, was cloned from a full-length cDNA library of Japanese flounder (Paralichthys olivaceus). The full-length cDNA comprises a 5'UTR of 202 bp, an open reading frame of 564 bp encoding a 187-amino-acid polypeptide and a 521-bp 3'UTR with a poly (A) tail. The putative protein has a predicted molecular mass of 21 kDa and an isoelectric point (pI) of 9.22. Amino acid sequence alignments showed that PoAkirin1 was 99% identical to the Scophthalmus maximus Akirin protein (ADK27484). Yeast two-hybrid assays identified two proteins that interact with PoAkirin1: PoHEPN and PoC1q. The cDNA sequences of PoHEPN and PoC1q are 672 bp and 528 bp, respectively. Real-time quantitative reverse-transcriptase polymerase chain reaction analysis showed that bacteria could induce the expressions of PoAkirin1, PoHEPN and PoC1q. However, the responses of PoHEPN and PoC1q to the bacterial challenge were slower than that of PoAkirin1. To further study the function of PoAkirin1, recombinant PoAkirin1 and PoHEPN were expressed in Escherichia coli and would be used to verify the PoAkirin1-PoHEPN binding activity. These results identified two proteins that potentially interact with PoAkirin1 and that bacteria could induce their expression. PMID:23651673

  6. Synthesis of LiFePO4/Pani/C composite as a cathode material for lithium ion battery

    NASA Astrophysics Data System (ADS)

    Rahayu, Iman; Hidayat, Sahrul; Aryadi, Lutfi

    2016-02-01

    In recent years, LiFePO4 studied intensively as a cathode material for Li-ion batteries because of high theoretical capacity, stability, and environmental friendly. However, its low intrinsic electronic conductivity. One way to improve its conductivity is addition of conductive material. Polyaniline (PANI) is one of the conductive polymer materials that widely studied because its unique physical and chemical properties which can be an insulator and conductor by doping-dedoping processes and has large potential application. The purpose of this research is to improve the conductivity of LiFePO4 with conductive polymer PANI. The method is performed by the addition of LiFePO4 during the polymerization process to form LiFePO4 polyaniline then added to the C-PANI with the addition of mass percent variation of 5%, 10%, 15%, 20% form-LiFePO4 composite PANI-C. In LiFePO4 added during polymerization PANI provide a smooth surface profile after composited with the carbon to LiFePO4-PANI-C compared to LiFePO4-C. LiFePO4-PANI-C composite provided higher conductivity is 18.45×10-4 S/cm compared to LiFePO4-C is 10.48×10-4 S/cm at 20% addition of carbon. This is due to PANI in LiFePO4 is added to the polyaniline polymerization process can act as a conductive adhesive to glue between carbon and LiFePO4.

  7. 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.

  8. Microwave synthesis of molybdenum doped LiFePO4/C and its electrochemical studies.

    PubMed

    Naik, Amol; P, Sajan C

    2016-05-10

    A Mo-doped LiFePO4 composite was prepared successfully from an iron carbonyl complex by adopting a facile and rapid microwave assisted solid state method. The evolution of gases from the iron precursor produces a highly porous product. The formation and substitution of Mo in LiFePO4 were confirmed by X-ray diffraction; surface analysis was carried out by scanning electron microscopy, field emission scanning electron microscopy, and transmission electron microscopy. The electrochemical properties of the substituted LiFePO4 were examined by cyclic voltammetry, electrochemical impedance spectroscopy and by recording charge-discharge cycles. It was observed that the as prepared composites consisted of a single phase orthorhombic olivine-type structure, where Mo(6+) was successfully introduced into the M2(Fe) sites. Incorporation of supervalent Mo(6+) introduced Li(+) ion vacancies in LiFePO4. The synthesized material facilitated lithium ion diffusion during charging/discharging due to the charge compensation effect and porosity. The battery performance studies showed that LiMo0.05Fe0.095PO4 exhibited a maximum capacity of 169.7 mA h g(-1) at 0.1 C current density, with admirable stability retention. Even at higher current densities, the retention of the specific capacity was exceptional. PMID:27071463

  9. 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.

  10. Microvascular and interstitial PO(2) measurements in rat skeletal muscle by phosphorescence quenching.

    PubMed

    Shibata, M; Ichioka, S; Ando, J; Kamiya, A

    2001-07-01

    To clarify the transport of O(2) across the microvessels in skeletal muscle, we designed an intravital laser microscope that utilizes a phosphorescence quenching technique to determine both the microvascular and tissue PO(2). After we injected the phosphorescent probe into systemic blood, phosphorescence excited by a N(2)-dye pulse laser was detected with a photomultiplier over a 10 microm in diameter area. In vitro and in vivo calibrations confirmed that the present method is accurate for PO(2) measurements in the range of 7-90 Torr (r = 0.958) and has a rapid response time. This method was then used to measure the PO(2) of microvessels with different diameters (40-130 microm) and of interstitial spaces in rat cremaster muscle. These measurements showed a significant drop in PO(2) in the arterioles after branching (from 74.6 to 46.6 Torr) and the presence of a large PO(2) gradient at the blood-tissue interface of arterioles (15-20 Torr). These findings suggest that capillaries are not the sole source of oxygen supply to surrounding tissue. PMID:11408447

  11. BiPO4: a better host for doping lanthanide ions.

    PubMed

    Naidu, Boddu Sanyasi; Vishwanadh, Bathula; Sudarsan, Vasanthakumaran; Vatsa, Rajesh Kumar

    2012-03-21

    In the present manuscript it is demonstrated that BiPO(4) is a better alternative to lanthanide phosphate host for making lanthanide ion-based luminescent materials. Hexagonal and monoclinic forms of BiPO(4) phase were prepared based on the reaction of Bi(3+) and PO(4)(3-) ions in ethylene glycol medium at 100 and 185 °C, respectively. From the differential thermal analysis (DTA) studies it is confirmed that the difference in the nucleation mechanism rather than the phase transition is responsible for the monoclinic phase formation at low temperatures (125 °C). Monoclinic BiPO(4) is quite stable and forms random solid solutions with lanthanide phosphates having both monoclinic (monazite) and tetragonal (xenotime) structures, as confirmed by XRD, FTIR and (31)P solid state nuclear magnetic resonance studies. On excitation corresponding to the (1)S(0)→(3)P(1) transition of Bi(3+) in BiPO(4):Ln samples, energy transfer from host to lanthanide ions takes place. The studies are quite relevant as there is a growing interest all over the world in replacing lanthanide based host used for different applications with easily available, easily purifiable and cheap main group elements (like Sb, Bi etc.) based hosts. PMID:22286329

  12. PoGOLite - a circumpolar balloon-borne mission for hard X-ray polarimetry

    NASA Astrophysics Data System (ADS)

    Pearce, Mark

    Mark Pearce For the PoGOLite Collaboration. KTH Royal Institute of Technology, Dept. of Physics, Stockholm, Sweden. pearce@kth.se Abstract Emission processes in astrophysical systems can yield polarised hard X-rays. The orientation of the polarisation plane is a powerful probe of the physical environment around compact astrophysical sources. Despite the wealth of sources accessible to polarisation measurements, and the importance of these measurements, it is 40 years since the last dedicated mission for X-ray polarimetry of point sources. PoGOLite is a balloon-borne hard X-ray polarimeter operating in the 25-100 keV energy band. Polarisation is determined using coincident Compton scattering and photo-absorption in a segmented array of plastic scintillators surrounded by a BGO anticoincidence system and a polyethylene neutron shield. PoGOLite was launched from the Esrange Space Center on July 12th 2013 with the Crab nebula and pulsar as primary observation targets. The mission was terminated on July 25th after an almost complete circumpolar flight. The PoGOLite mission was conducted as a collaboration between Swedish, Japanese, Russian and US scientific teams. The PoGOLite circumpolar mission will be reviewed and the outcome of the 2013 flight discussed.

  13. Pressure-dependent Raman spectra of β-Ca3(PO4)2 whitlockite

    NASA Astrophysics Data System (ADS)

    Zhai, Shuangmeng; Wu, Xiang; Xue, Weihong

    2015-04-01

    The pressure dependence of Raman spectra for whitlockite β-Ca3(PO4)2 was investigated up to 18.0 GPa using a diamond-anvil cell at room temperature. The Raman frequencies of all observed bands for β-Ca3(PO4)2 continuously increase with increasing pressure. The quantitative analysis of pressure dependence of Raman bands for the sample shows that the ν 3 asymmetric and ν 1 symmetric stretching vibrations are with the larger pressure coefficients (from 3.44 to 4.59 cm-1 GPa-1) and that the ν 4 bending and ν 2 deforming vibrations are with the smaller pressure coefficients (from 1.46 to 3.12 cm-1 GPa-1). Combined with previous result, the isothermal mode Grüneisen parameters of β-Ca3(PO4)2 were calculated. The splitting of the PO4 symmetric stretching ν 1 vibrations changes during compression and disappears around 15.4 GPa, which may be attributed to the evolution of PO4 tetrahedra under high pressure.

  14. Synchrotron powder study of Na3V(PO3)3N.

    PubMed

    Kim, Minwoong; Kim, Seung-Joo

    2013-06-01

    Polycrystalline tris-odium vanadium(III) nitridotriphosphate, Na3V(PO3)3N, was prepared by thermal nitridation of a mixture of NaPO3 and V2O5. The title compound is isotypic with Na3Al(PO3)3N. In the crystal, the P-atom and the three O-atom sites are on general positions, whereas the Na-, V- and N-atom sites are located on threefold rotation axes. The P atom is coordinated by three O atoms and one N atom in form of a slightly distorted tetra-hedron. Three PO3N tetra-hedra build up a nitridotriphosphate group, (PO3)3N, by sharing a common N atom. The V atom is coordinated by six O atoms in form of a slightly distorted octa-hedron. The Na(+) ions occupy three crystallographically distinct sites. One Na(+) ion is situated in an irregular polyhedral coordination environment composed of six O atoms and one N atom, while the other two Na(+) cations are surrounded by six and nine O atoms, respectively. PMID:23794965

  15. 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

  16. Determination of the Lamb-Moessbauer factors of LiFePO{sub 4} and FePO{sub 4} for electrochemical in situ and operando measurements in Li-ion batteries

    SciTech Connect

    Aldon, L.

    2010-01-15

    {sup 57}Fe Moessbauer spectroscopy is a powerful tool to investigate redox reactions during in electrochemical lithium insertion/extraction processes. Electrochemical oxidation of LiFe{sup II}PO{sub 4} (triphylite) in Li-ion batteries results in Fe{sup III}PO{sub 4} (heterosite). LiFePO{sub 4} was synthesized by solid state reaction at 800 deg. C under Ar flow from Li{sub 2}CO{sub 3}, FeC{sub 2}O{sub 4}.2H{sub 2}O and NH{sub 4}H{sub 2}PO{sub 4} precursors in stoichiometric composition. FePO{sub 4} was prepared from chemical oxidation of LiFePO{sub 4} using bromine as oxidative agent. For both materials a complete {sup 57}Fe Moessbauer study as a function of the temperature has been carried out. The Debye temperatures are found to be theta{sub M}=336 K for LiFePO{sub 4} and theta{sub M}=359 K for FePO{sub 4}, leading to Lamb-Moessbauer factors f{sub 300K}=0.73 and 0.77, respectively. These data will be useful for a precise estimation of the relative amounts of each species in a mixture. - Graphical abstract: Relative amount of FePO{sub 4} obtained by Moessbauer and electrochemical data. We have corrected Moessbauer spectral intensities with our f factor of both LiFePO{sub 4} and FePO{sub 4}. Open (filled) squares correspond to values obtained during charging (discharging) process. The dashed line, given as a guideline for the eye, corresponds to the ideal case were amounts deduced from different experimental measurements are equal.

  17. Structural study of polymorphism and thermal behavior of CaZr(PO4)2

    NASA Astrophysics Data System (ADS)

    Bregiroux, Damien; Wallez, Gilles; Popa, Karin

    2015-03-01

    The crystal structure of CaZr(PO4)2 has been revised by ab initio Rietveld analysis of X-ray powder diffraction data. At room temperature, CaZr(PO4)2 crystallizes in the orthorhombic space group Pna21 (Z = 4). Differential thermal analysis suggests a reversible second order transition at 1000 °C confirmed by high temperature XRD analysis that brings out the existence of a high temperature form, very similar to the room temperature one, but more symmetrical (Pnma, Z = 4). Analysis of the crystal parameters evolution during heating reveals that CaZr(PO4)2 exhibits a quite low thermal expansion coefficient of 6.11·10-6 K-1. This value stems from a combination of several mechanisms, including Coulombic repulsion and bridging oxygen rocking motion.

  18. 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

  19. (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

  20. 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.

  1. 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.

  2. 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.

  3. First-principles elastic stiffness of LaPO4 monazite

    NASA Astrophysics Data System (ADS)

    Wang, Jingyang; Zhou, Yanchun; Lin, Zhijun

    2005-08-01

    In this letter, the full set of elastic coefficients of LaPO4 monazite is presented based on the first-principles plane-wave pseudopotential total energy method. Mechanical parameters (bulk modulus, shear modulus, Young's moduli, and Poisson's ratio) are also presented and compared with experimental results for polycrystalline monazite. The responses of electronic structure and chemical bonds to a series of {010}⟨001⟩ shear strains are examined in order to study the mechanism of low shear strain resistance. The results show that small shear moduli originate from the inhomogeneous strengths of atomic bonds. For example, the weak La-O bonds accommodate the shear strain locally, while the PO4 tetrahedra are almost rigid. The theoretical elastic stiffness may be useful to understand the deformation mechanisms of LaPO4 monazite.

  4. Sequential determination of 210Po and uranium radioisotopes in drinking water by alpha-particle spectrometry.

    PubMed

    Benedik, L; Vasile, M; Spasova, Y; Wätjen, U

    2009-05-01

    Procedures for the sequential determination of low level (210)Po and uranium radioisotopes in drinking water by alpha-particle spectrometry are presented. After addition of (208)Po and (232)U tracers, the radionuclides were preconcentrated from water samples by co-precipitation on Fe(OH)(3) or MnO(2) at pH 9 using ammonia solution. The (210)Po source was prepared by spontaneous deposition onto a copper disc either before or after uranium separation. The uranium source for alpha-particle counting was prepared by micro co-precipitation with CeF(3). The procedures were tested on mineral water and the results obtained are compared. PMID:19231220

  5. Ultra-high power capabilities in amorphous FePO4 thin films

    NASA Astrophysics Data System (ADS)

    Gandrud, Knut B.; Nilsen, Ola; Fjellvåg, Helmer

    2016-02-01

    Record breaking electrochemical properties of FePO4 have been found through investigation of the thickness dependent electrochemical properties of amorphous thin film electrodes. Atomic layer deposition was used for production of thin films of amorphous FePO4 with highly accurate thickness and topography. Electrochemical characterization of these thin film electrodes revealed that the thinner electrodes behave in a pseudocapacitive manner even at high rates of Li+ de/intercalation, which enabled specific powers above 1 MW kg-1 FePO4 to be obtained with minimal capacity loss. In addition, a self-enhancing kinetic effect was observed during cycling enabling more than 10,000 cycles at current rates approaching that of a supercapacitor (11s charge/discharge). The current findings may open for construction of ultra-high power battery electrodes that combines the energy density of batteries with the power capabilities of supercapacitors.

  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. 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

  8. 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

  9. PoLi: A Virtual Screening Pipeline Based On Template Pocket And Ligand Similarity

    PubMed Central

    Roy, Ambrish; Srinivasan, Bharath; Skolnick, Jeffrey

    2015-01-01

    Often in pharmaceutical research, the goal is to identify small molecules that can interact with and appropriately modify the biological behavior of a new protein target. Unfortunately, most proteins lack both known structures and small molecule binders, prerequisites of many virtual screening, VS, approaches. For such proteins, ligand homology modeling, LHM, that copies ligands from homologous and perhaps evolutionarily distant template proteins, has been shown to be a powerful VS approach to identify possible binding ligands. However, if we want to target a specific pocket for which there is no homologous holo template protein structure, then LHM will not work. To address this issue, in a new pocket based approach, PoLi, we generalize LHM by exploiting the fact that the number of distinct small molecule ligand binding pockets in proteins is small. PoLi identifies similar ligand binding pockets in a holo-template protein library, selectively copies relevant parts of template ligands and uses them for VS. In practice, PoLi is a hybrid structure and ligand based VS algorithm that integrates 2D fingerprint-based and 3D shape-based similarity metrics for improved virtual screening performance. On standard DUD and DUD-E benchmark databases, using modeled receptor structures, PoLi achieves an average enrichment factor of 13.4 and 9.6 respectively, in the top 1% of the screened library. In contrast, traditional docking based VS using AutoDock Vina and homology-based VS using FINDSITEfilt have an average enrichment of 1.6 (3.0) and 9.0 (7.9) on the DUD (DUD-E) sets respectively. Experimental validation of PoLi predictions on dihydrofolate reductase, DHFR, using differential scanning fluorimetry, DSF, identifies multiple ligands with diverse molecular scaffolds, thus demonstrating the advantage of PoLi over current state-of-the-art VS methods. PMID:26225536

  10. 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

  11. 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. PMID:23910327

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Optical Properties and Electrochemical Performance of LiFePO4 Thin Films Deposited on Transparent Current Collectors.

    PubMed

    Lee, HyunSeok; Yim, Haena; Kim, Kwang-Bum; Choi, Ji-Won

    2015-11-01

    LiFePO4 thin film cathodes are deposited on various transparent conducting oxide thin films on glass, which are used as cathode current collectors. The XRD patterns show that the thin films have the phase of LiFePO4 with an ordered olivine structure indexed to the orthorhombic Pmna space group. LiFePO4 thin film deposited on various TCO glass substrates exhibits transmittance of about 53%. The initial specific discharge capacities of LiFePO4 thin films are 25.0 μAh/cm2 x μm on FTO, 33.0 μAh/cm2 x μm on ITO, and 13.0 μAh/cm2 x μm on AZO coated glass substrates. Interestingly, the retention capacities of LiFePO4 thin films are 76.0% on FTO, 31.2% on ITO, and 37.7% on AZO coated glass substrates at 20th cycle. The initial specific discharge capacity of the LiFePO4/FTO electrode is slightly lower, but the discharge capacities of the LiFePO4/FTO electrode relatively decrease less than those of the others such as LiFePO4/ITO and LiFePO4/AZO with cycling. The results reported here provide the high transparency of LiFePO4 thin films cathode materials and the good candidate as FTO current collector of the LiFePO4 thin film cathode of transparent thin film rechargeable batteries due to its high transparency and cyclic retention. PMID:26726564

  17. LIF upregulates poFUT1 expression and promotes trophoblast cell migration and invasion at the fetal–maternal interface

    PubMed Central

    Liu, S; Wang, J; Qin, H-M; Yan, X-M; Yang, X-S; Liu, C; Yan, Q

    2014-01-01

    Trophoblast cell migration and invasion are crucial for the establishment of a successful pregnancy. Protein O-fucosyltransferases, such as poFUT1 and poFUT2, catalyze the O-fucosylation of proteins and have important roles in embryonic development. Leukemia inhibitory factor (LIF) is a critical cytokine in the regulation of embryonic development and implantation. However, the exact roles of poFUTs in embryo migration and invasion and the effects of LIF on the expression of poFUTs have not been studied in detail. In the current study, we showed that poFUT1 and LIF were highly expressed in human trophoblast cells and in the serum of women during the first trimester of a normal pregnancy. However, in patients with threatened abortion, poFUT1 and LIF levels were found to be reduced. There were no significant differences in the expression levels of poFUT2 between the two groups. The migration and invasion potential of trophoblasts in an explant culture and in an in vitro implantation model was decreased or increased upon altering poFUT1 expression levels by siRNA or cDNA transfection. Our results also revealed that LIF upregulated the expression of poFUT1. The upregulation of poFUT1 by LIF promoted trophoblast cell migration and invasion at the fetal–maternal interface by activating the PI3K/Akt signaling pathway. Taken together, these study findings suggest that poFUT1 may be used as a marker of embryo implantation. PMID:25165882

  18. 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

  19. Variations of 210Po activity in mussel (Perna viridis) of Samut Sakhon and its contribution to dose assessment

    NASA Astrophysics Data System (ADS)

    Porntepkasemsan, B.; Srisuksawad, K.; Kulsawat, W.

    2015-05-01

    The activities of 210Po and its effective dose in green mussel (Perna viridis) collected from a mussel farming area in Samut Sakhon province during the period of 20122013 are presented. Several parameters including maximum shell length and the physiological performance of mussels using condition index and physical properties of seawater (pH, salinity, conductivity, TDS, DO and cation-anion elements) were measured. Each individual mussel was measured for its maximum shell length which was adopted as size class. The activity concentration of 210Po was determined spectroscopically through its 5.30 MeV alpha particle emission, using 209Po as an internal tracer. The 210Po activity concentration in mussels was found to vary between 1.044 and 6.951 Bq/kg wet weight. The 210Po concentration was higher in smaller-sized (≤35 mm) and lower in larger ones (40-70 mm). This confirmed that larger mussels have lower 210Po activities on a weight basis. The 210Po body burden (activity per mussel) ranged from 1.035 to 17.183 mBq. Contrary to the 210Po concentrations, results of the body burden revealed the lower activities in smaller-sized mussels (≤35 mm) and the higher in larger-sized ones (40-70 mm). The type of fluctuations observed with 210Po concentrations were interpreted as a seasonal effect. Total annual effective 210Po dose due to mussel consumption was calculated to be in the range of 3.081 to 16.401 pSv. Based on the international guideline, the average dose calculated due to 210Po in mussels of Samut Sakhon would not pose any significant radiological impact on human health and the mussels are considered to be safe for consumption.

  20. 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.

  1. Adsorption interaction in the molecular hydrogen-aluminophosphate AlPO-5 zeolite system

    NASA Astrophysics Data System (ADS)

    Grenev, I. V.; Gavrilov, V. Yu.

    2015-03-01

    The adsorption interaction between molecular hydrogen and atoms forming the lattice of AlPO-5 zeolite is studied. The potential of intramolecular interaction is calculated by summing the potentials of individual pairwise H2-O(Al, P) interactions in a fragment of the zeolite structure with a volume of ˜32 nm3. Isopotential surfaces are constructed that allow determination of the shape of zeolite microchannels and the places of the preferential localization of sorbate molecules in the porous space. The calculated and experimental values of the Henry constant of H2 adsorption on AlPO-5 at 77 K are compared.

  2. 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.

  3. 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. PMID:23562435

  4. TL-OSL study of Li3PO4: Mg, Cu phosphor

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

    In the present work, we report the thermoluminescence and optically stimulated luminescence properties of Mg and Cu doped Li3PO4 phosphor. The phosphor was synthesized by precipitation method. The thermoluminescence dosimetric peak temperature for the phosphor varies with concentrations of Mg and Cu. Li3PO4 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.

  5. 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.

  6. The Digital Universe Coalition: Building a Prototype NVO E/PO Portal

    NASA Astrophysics Data System (ADS)

    Mendez, B.; Craig, N.; Haisch, B.; Lindblom, J.; Hanisch, R.; Summers, F.; Abbott, B.

    2004-05-01

    The National Virtual Observatory (NVO) holds tremendous potential for Education and Public Outreach (E/PO) opportunities. The possibilities for E/PO with the NVO, which promises to make widely available the great majority of the world's astronomical data, are too numerous for any one E/PO effort to ever hope to develop. Therefore, it is critical that the NVO E/PO program develop an infrastructure and tools flexible enough that any E/PO program can make use of it. In response to the recommendations of the NVO science definition team, UC Berkeley's SEGway program conducted needs assessment surveys of potential non-traditional (i.e. non-scientist) NVO user communities. The SEGway team wished to use the results of these surveys to design a demonstration website that could show some of the potential capabilities of NVO E/PO. SEGway established an informal partnership with STScI, AMNH/Hayden Planetarium, and ManyOne Network to explore how to assemble the infrastructure and tools for NVO E/PO and to construct a demonstration portal that makes use of NVO resources. We called this partnership The Digital Universe Coalition. This prototype displays AMNH/Hayden's Digital Universe star catalog of approximately 100,000 stars, based largely on HIPPARCOS parallaxes, in a virtual three-dimensional space. Three types of user-interactive data display and/or navigation are possible: an Earth-based view of the sky with the option of displaying constellations; a spaceship-based view moving through space; and a "god's-eye" view of the local neighborhood from an external vantage point. One key feature of this demo is the linking of user-selectable locations in the sky to the online Digitized Sky Survey data sets. A second feature is a set of links for educational content on a handful of selected objects. Both of these capabilities will be extended further as we plan to begin development of a much more robust and complete E/PO portal for the NVO.

  7. 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.

  8. Nanocomposites with Ca and PO4 release: Effects of reinforcement, dicalcium phosphate particle size and silanization

    PubMed Central

    Xu, Hockin H. K.; Weir, Michael D.; Sun, Limin

    2009-01-01

    Objectives Nano-particles of dicalcium phosphate anhydrous (DCPA) were synthesized in our laboratory for the first time and incorporated into a dental resin. Our goal was to develop a mechanically strong dental composite that has Ca and PO4 ion release to combat tooth caries, and to investigate the effects of whisker reinforcement, DCPA particle size and silanization. Methods DCPA nano-particles and two larger DCPA particles were used with nano-silica-fused whiskers as fillers in a resin matrix. Composite mechanical properties were measured via three-point flexure, and the release of Ca and PO4 ions were measured vs. time. Results Using DCPA nano-particles with a diameter of 112 nm, the composite at a DCPA:whisker mass ratio of 1:1 had a flexural strength (mean ± sd; n = 5) of (112 ± 17) MPa, not significantly different from (112 ± 14) MPa of a commercial non-releasing composite; both were higher than (29 ± 7) MPa for the composite at DCPA:whisker of 1:0 (p < 0.05). The composite with DCPA particle size of 112 nm released Ca to a concentration of 0.85 mmol/L and PO4 of 3.48 mmol/L, higher than Ca of 0.67 mmol/L and PO4 of 1.11 mmol/L using DCPA with 12 μm particle size (p < 0.05). Silanization of DCPA increased the composite strength at DCPA:whisker of 1:0 compared to that without silanization, but decreased the Ca and PO4 release (p < 0.05). Increasing the DCPA particle surface area increased the Ca and PO4 release. Significance Decreasing the DCPA particle size increased the Ca and PO4 release; whisker reinforcement increased the composite strength by 2 to 3 fold. The nano DCPA-whisker composites, with high strength and Ca and PO4 release, may provide the needed, unique combination of stress-bearing and caries-inhibiting capabilities. PMID:17339048

  9. d0 ferromagnetism in black phosphorous oxide caused by surface P-O bonds

    NASA Astrophysics Data System (ADS)

    Gui, Q. F.; Sun, L. L.; Liu, L. Z.; Wu, X. L.; Chu, Paul K.

    2016-02-01

    The room-temperature d0 ferromagnetism in black phosphorous (BP) oxide is investigated experimentally and theoretically. Electrochemical oxidation does not alter the single-crystal structure of BP and the degree of oxidation depends on the oxidation time, thereby resulting in changeable d0 ferromagnetism caused by surface P-O bonds. First-principles calculation reveals that different surface P-O bonds have different binding energies and contributions to the ferromagnetism and the bridge and dangling oxygen atoms are responsible for the observed ferromagnetism which stems from p orbital spin polarization of the oxygen and phosphorus atoms.

  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. 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.

  13. Passive detector for measurement of the implanted (sup 210)Po activity in glass

    NASA Astrophysics Data System (ADS)

    Meesen, G.; Uyttenhove, J.; Poffijn, A.; van Laere, K.; Buysse, J.

    1994-08-01

    It is a well known fact that radon is the most important factor in the natural radiation background. For complete dose calculations we need information about the radon concentration up to 25 years ago. As suggested by C. Samuelsson et al. in 1988, the activity of the implanted radon daughter (sup 210)Po can be used to reconstruct the radon activity over the past decades. For large scale surveys in dwellings a passive detector based on polycarbonate foils has been investigated. This system has a sufficient sensitivity to detect (sup 210)Po levels down to 1 Bq/m(sup 2) with a 6 month measuring period.

  14. {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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. The γ-polymorph of AgZnPO4 with an ABW zeolite-type framework topology

    PubMed Central

    Assani, Abderrazzak; Saadi, Mohamed; El Ammari, Lahcen

    2010-01-01

    The γ-polymorph of the title compound, silver zinc orthophos­phate, was synthesized under hydro­thermal conditions. The structure consists of ZnO4, PO4 and AgO4 units. The coord­ination spheres of ZnII and PV are tetra­hedral, whereas the AgI atom is considerably distorted from a tetra­hedral coordination. Each O atom is linked to each of the three cations. An elliptic eight-membered ring system is formed by corner-sharing of alternating PO4 and ZnO4 tetra­hedra, leading to a framework with an ABW-type zeolite structure. The framework encloses channels running parallel to [100] in which the Ag cations are located, with Ag⋯Ag contacts of 3.099 (3) Å. This short distance results from d 10⋯d 10 inter­actions, which play a substantial role in the crystal packing. The structure of γ-AgZnPO4 is distinct from the two other polymorphs α-AgZnPO4 and β-AgZnPO4, but is isotypic with NaZnPO4-ABW, NaCoPO4-ABW and NH4CoPO4-ABW. PMID:21588789

  1. 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.

  2. Hexamethylenetetramine assisted hydrothermal synthesis of BiPO4 and its electrochemical properties for supercapacitors

    NASA Astrophysics Data System (ADS)

    Nithya, V. D.; Kalai Selvan, R.; Vasylechko, Leonid

    2015-11-01

    The well defined microstructures of BiPO4 were successfully synthesized by the facile hexamethylenetetramine (HMT) assisted hydrothermal method. The low temperature monoclinic BiPO4 structure with space group P21/n, were obtained from X-ray diffraction (XRD) for the pristine and HMT-assisted BiPO4 with 1, 3, 5 and 10 mmole concentration. A transformation from low temperature monazite-type phase to the high temperature SbPO4-type phase of BiPO4 was observed at the 10 mmole concentration. There was a variation in the morphology from polyhedron to octahedra-like and finally into cube shape upon an increase in concentration of HMT. The role of reaction time in the morphology of BiPO4 particles was investigated. The selected area electron diffraction (SAED) pattern elucidated the ordered dot pattern and the calculated d-spacing revealed the formation of BiPO4. An increased specific capacitance of HMT assisted materials (202 F/g) compared with pristine BiPO4 (89 F/g) at 5 mA/cm2 was observed upon morphological variation due to HMT addition.

  3. 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.

  4. Synthesis of few-layer MoS2 nanosheet-loaded Ag3PO4 for enhanced photocatalytic activity.

    PubMed

    Song, Yanhua; Lei, Yucheng; Xu, Hui; Wang, Cheng; Yan, Jia; Zhao, Haozhu; Xu, Yuanguo; Xia, Jiexiang; Yin, Sheng; Li, Huaming

    2015-02-21

    Novel few-layer MoS2/Ag3PO4 composites were fabricated. The results indicated that Ag3PO4 nanoparticles were directly formed on the surface of few-layer MoS2. The physical and chemical properties of the few-layer MoS2/Ag3PO4 composite photocatalysts were tested in order to investigate the effects of few-layer MoS2 on the photocatalytic activity of Ag3PO4. The photocatalytic activity of the few-layer MoS2/Ag3PO4 composites was evaluated by the photocatalytic degradation of Rhodamine B (RhB) and bisphenol A (BPA) under visible light irradiation. The photocatalytic activity of the few-layer MoS2/Ag3PO4 composites was higher than that of pure Ag3PO4. The optimal few-layer MoS2 content for the organic pollutant degradation of the heterojunction structures was determined. The synergic effect between few-layer MoS2 and Ag3PO4 was found to lead to an improved photogenerated carrier separation. The stability and the possible photocatalytic mechanism of the composites were also discussed. PMID:25567674

  5. 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.

  6. 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…

  7. 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. PMID:26682389

  8. Synthesis, non-isothermal kinetic and thermodynamic studies of the formation of LiMnPO4 from NH4MnPO4·H2O precursor

    NASA Astrophysics Data System (ADS)

    Sronsri, Chuchai; Noisong, Pittayagorn; Danvirutai, Chanaiporn

    2014-06-01

    NH4MnPO4·H2O was successfully synthesized by precipitating method. The LiMnPO4 was successfully generated through solid state reaction between synthesized NH4MnPO4·H2O precursor and Li2CO3. The morphologies were observed to depend on the reaction temperatures. The thermal decomposition of NH4MnPO4·H2O and the formation process of LiMnPO4 were confirmed by TG/DTG/DTA, FTIR, AAS/AES, XRD and SEM methods. The average crystallite size of NH4MnPO4·H2O, Mn2P2O7 and LiMnPO4 were found to be around 51.2, 44.9 and 48.1 nm, respectively. The non-isothermal kinetic parameters (kinetic triplet: Eα, A, g(α)) of the formation process of LiMnPO4 were evaluated from TG data by using Ozawa-Flynn-Wall and Kissinger-Akahira-Sunose methods. The iterative methods of both equations were carried out to determine the exact values of Eα. The Coats-Redfern equation and kinetic compensation effects were successfully applied to confirm the activation energy and the most probable mechanism functions of the formation of LiMnPO4. The thermodynamic functions (ΔH≠, ΔS≠, ΔG≠) of the transition state complexes of the formation of LiMnPO4 were calculated from the kinetic parameters for the first time.

  9. 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

  10. 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.

  11. 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

  12. Structural and Electrical Properties of Lithium-Ion Rechargeable Battery Using the LiFePO4/Carbon Cathode Material.

    PubMed

    Kim, Young-Sung; Jeoung, Tae-Hoon; Nam, Sung-Pill; Lee, Seung-Hwan; Kim, Jea-Chul; Lee, Sung-Gap

    2015-03-01

    LiFePO4/C composite powder as cathode material and graphite powder as anode material for Li-ion batteries were synthesized by using the sol-gel method. An electrochemical improvement of LiFePO4 materials has been achieved by adding polyvinyl alcohol as a carbon source into as-prepared materials. The samples were characterized by elemental analysis (EA), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-EM). The chemical composition of LiFePO4/C powders was in a good agreement with that of the starting solution. The capacity loss after 500 cycles of LiFePO4/C cell is 11.1% in room temperature. These superior electrochemical properties show that LiFePO4/C composite materials are promising candidates as cathode materials. PMID:26413683

  13. 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.

  14. 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...

  15. 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 Section 154.405 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Containment Systems...

  16. 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 Section 154.405 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Containment Systems...

  17. A vibrational spectral study of hydrated tantalum phosphate(TaPO 5) phases

    NASA Astrophysics Data System (ADS)

    Stranford, G. T.; Condrate, R. A.

    1990-04-01

    Infrared and Raman spectra were measured for various hydrated tantalum phosphate (TaPO 5) materialsafter dehydration at various temperatures, and the spectral differences were interpreted on the basis of structure. The structural nature of water along with protonated phosphate and TaO 6 groups in the amorphous hydrated materials was discussed.

  18. High-pressure phase transitions of ScPO[subscript 4] and YPO[subscript 4

    SciTech Connect

    Zhang, F.X.; Wang, J.W.; Lang, M.; Zhang, J.M.; Ewing, R.C.; Boatner, L.A.

    2010-01-12

    ScPO{sub 4} and YPO{sub 4} with the tetragonal zircon-structure were studied at room temperature and pressures up to -50 GPa. Pressure-induced phase transitions to the sheelite structure occur at 30 GPa for ScPO{sub 4} and 16.3 GPa for YPO{sub 4}, respectively. In addition to the scheelite-type high-pressure phase, an intermediate phase with the monoclinic monazite-type structure formed during the phase transition process of YPO{sub 4}. The high-pressure phases of ScPO{sub 4} and YPO{sub 4} are not quenchable on pressure release. The pressure dependence of the total energy of the different phases was calculated using density-functional method, and the results confirm the experimentally observed phase relations under pressure. Structural parameters and compressibility of each phase were determined by refinement of the x-ray diffraction patterns. The high-pressure phase of ScPO{sub 4} has a very large bulk modulus [376(8) GPa].

  19. 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

  20. 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

  1. Electron-impact study of PO2 using the R-matrix method

    NASA Astrophysics Data System (ADS)

    Bharadvaja, Anand; Kaur, Savinder; Baluja, K. L.

    2013-06-01

    The R-matrix approach is used to study the electron scattering from PO2 radical at low electron impact energies. The elastic scattering phenomenon is studied in static-exchange, one-state and many-states close-coupling approximation. The elastic differential cross sections, corresponding momentum-transfer cross sections, and collision frequency are calculated in the one-state configuration interaction approximation only. Calculations reveal a stable bound state of PO2- having symmetry 1A1, a configuration of ⋯8a12,⋯2b12,⋯5b22,⋯1a22, and vertical electron affinity of 2.94 eV. The excited state of anion PO2- having symmetry 3B1 is also just bound relative to the ground state of PO2 at its equilibrium geometry. The shape, core-excited, and Feshbach resonances are analyzed in different symmetries up to 7 eV. The partial waves up to l=4 are used to represent continuum electron. The converged cross sections are obtained for the partial waves having l greater than 4 by applying Born correction. Certain interesting spectroscopic properties of radical are also reported.

  2. Evaluation of 210Pb and 210Po in cigarette tobacco produced in Brazil.

    PubMed

    Peres, A C; Hiromoto, G

    2002-01-01

    Cigarette smoking is one of the pathways that might contribute significantly to the increase in the radiation dose reaching man, due to the relatively large concentrations of 210Pb and 210Po found in tobacco leaves. In the present study, the concentrations of these two radionuclides were determined in eight of the most frequently sold cigarette brands produced in Brazil. 210Pb was determined by counting the beta activity of 210Bi with a gas flow proportional detector after radiochemical separation and precipitation of PbCrO4. 210Po was determined by alpha spectrometry using a surface barrier detector after radiochemical separation and spontaneous deposition of Po on a copper disk. The results showed concentrations ranging from 11.9 to 30.2 mBq per gram of dry tobacco for 210Pb and from 10.9 to 27.4 mBq per gram of dry tobacco for 210Po. The collective committed effective dose resulting from the use of cigarettes produced in Brazil per year is estimated to be 1.5 x 10(4) man-Sv. PMID:12141603

  3. 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…

  4. 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.

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

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Substances § 721.9675 Titanate , di-po-tas-sium. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as titanate , dipotassium (CAS No. 12056-51-8) (PMN P-90...), and (q). In addition, a significant new use of the substance is importation of the PMN substance...

  6. 40 CFR 721.9675 - Titanate [Ti6O13 (2-)], di-po-tas-sium.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Substances § 721.9675 Titanate , di-po-tas-sium. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as titanate , dipotassium (CAS No. 12056-51-8) (PMN P-90...), and (q). In addition, a significant new use of the substance is importation of the PMN substance...

  7. 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),...

  8. 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.

  9. 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. PMID:21970439

  10. Phase dependent structural and electronic properties of Lanthanum Orthophosphate (LaPO4)

    NASA Astrophysics Data System (ADS)

    Neupane, Mahesh; Garrett, Gregory; Rudin, Sergey; Andzelm, Jan

    Lanthanum orthophosphate (LaPO4) belongs to the family of rare-earth (RE) orthophosphates. The La-ion lacks valence 4f-electron, so for it to exhibit f-electron dependent physics, it must be doped with additional RE elements. In the bulk form, LaPO4 exist in both a stable monoclinic and a metastable hexagonal phase, which both possess indirect energy transition characteristics. Though the overall optoelectronic properties of the RE-doped LaPO4 depend on the accuracy of the observed bulk energy gap, the reported experimental and theoretical energy gaps varies between ~81,2 and ~53 eV, respectively. Through this theoretical study, we attempt to establish a correlation between electronic properties of bulk LaPO4 and various levels of first principle theories. Compared to experimental data, the PBE0 functional over-predicts energy gaps and the energy differences between the indirect-to-direct transition energies by 25%. The HSE06 gives a good description of electronic properties and predicts the energy gaps to be 7.68 (monoclinic) and 7.29 eV (hexagonal). Analysis on the structural stability also reveals that the total energy difference between the two phases is 6meV, consistent with the experimentally observed instantaneous pressure and temperature dependent phase transition.

  11. Controlled formation of core-shell structures with uniform AlPO4 nanoshells.

    PubMed

    Yang, Fen-Li; Zhang, Wei; Chi, Zi-Xiang; Cheng, Fu-Quan; Chen, Ji-Tao; Cao, An-Min; Wan, Li-Jun

    2015-02-18

    Uniform AlPO4 nanoshells are successfully achieved on different core materials by controlling their formation kinetics in solution. The application of this coating protocol to LiCoO2 shows an obvious improvement in its battery performance. PMID:25587930

  12. 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

  13. Mössbauer study on LiFePO4 cathode material for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Hannoyer, B.; Prince, A. A. M.; Jean, M.; Liu, R. S.; Wang, G. X.

    2006-01-01

    Crystalline LiFePO4 has been synthesized using solid-state, spray pyrolysis, and wet chemical methods. The crystal parameters were obtained from Rietveld’s refinement methods of the X-ray diffraction patterns. A detailed investigation of the Fe valency carried out using Mössbauer spectroscopy at room temperature indicates that Fe is predominantly present in its bivalent state.

  14. Mössbauer study on LiFePO4 cathode material for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Hannoyer, B.; Prince, A. A. M.; Jean, M.; Liu, R. S.; Wang, G. X.

    Crystalline LiFePO4 has been synthesized using solid-state, spray pyrolysis, and wet chemical methods. The crystal parameters were obtained from Rietveld's refinement methods of the X-ray diffraction patterns. A detailed investigation of the Fe valency carried out using Mössbauer spectroscopy at room temperature indicates that Fe is predominantly present in its bivalent state.

  15. Sm(3+)-doped Ba3Bi(PO4)3 orange reddish emitting phosphor.

    PubMed

    Yang, Fu; Yang, Zhiping; Yu, Quanmao; Liu, Yufeng; Li, Xu; Lu, Fachun

    2013-03-15

    Ba(3)Bi(PO(4))(3):Sm(3+) phosphors were prepared via solid state reaction process. The crystal structure of the phosphor was characterized by XRD. The PL properties of Ba(3)Bi(PO(4))(3):Sm(3+) were investigated. The optimized phosphor with the composition of Ba(3)Bi(PO(4))(3):0.06Sm(3+) presents the several excitation bands from 300 to 500 nm, and exhibits very good luminescence properties. Under the excitation of ultraviolet 373, 401 and blue 467 nm, the phosphor presented red luminescence with dominating emissions at 563, 599, 646 and 709 nm, corresponding to (4)G(5/2)→(6)H(J) (J=5/2, 7/2, 9/2 and 11/9) transitions, respectively. The critical distance was calculated to be 21.0 Å. The energy transfer type between Sm(3+) ions was confirmed as the d-d interaction by using the Van Uitert model. The chromatic properties of the typical sample Ba(3)Bi(PO(4))(3):0.06Sm(3+) phosphor have been found to have chromaticity coordinates of (0.59, 0.38), under the excitation of 401 nm. PMID:23391850

  16. Luminescence properties of phosphate phosphor Ba3Y(PO4)3:Sm3+

    NASA Astrophysics Data System (ADS)

    Yang, Fu; Liu, Yufeng; Tian, Xiaodong; Dong, Guoyi; Yu, Quanmao

    2015-05-01

    A series of reddish orange-emitting phosphate phosphors Ba3Y1-x(PO4)3:xSm3+(0.01≤x≤0.20) were synthesized by solid-state reaction. X-ray diffraction and photoluminescence spectra were utilized to characterize the structure and luminescence properties of as-synthesized phosphors. The optimized phosphors Ba3Y0.95(PO4)3:0.05Sm3+ present several excitation bands from 300 to 500 nm, and exhibit intense reddish orange-emitting properties. The energy transfer type between Sm3+ ions was confirmed as d-d interaction by using Van Uitert model. The chromatic properties of the typical sample Ba3Y(PO4)3:0.05Sm3+ phosphor have been found to have chromaticity coordinates of (0.583, 0.405), which are located in reddish orange region under the excitation of 401 nm. These results indicated that Ba3Y(PO4)3:Sm3+ phosphors have potential applications in the field of lighting and display due to their effective excitation in the near-ultraviolet range.

  17. 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…

  18. 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.

  19. Marking the tip location of PO2 microelectrodes or glass micropipettes.

    PubMed

    Nair, P; Spande, J I; Whalen, W J

    1980-11-01

    The necessity of localizing the PO2 recording sites in the carotid body of cats has led us to modify our O2 microelectrode to be able to mark the position of the tip. Gold is sputtered on the electrode, and then iron is plated on the gold. The carotid body of cats was exposed, and PO2 was recorded at different depths in the body after which iron was deposited. At the end of the experiment, the excised body was placed in a 1:1 mixture of 4% potassium ferrocyanide and 4% acetic acid for 1 h or more. After that, the body was fixed in a 1:1 mixture of 40% formaldehyde and 95% ethyl alcohol for 1-2 days. Paraffin sections cut at 10 micrometer revealed the recording sites as bright blue spots. Since the cathode size can be made as small as 1 micrometer, discrete spots (a few microns or larger depending on current and time) can be produced at the PO2 recording sites. Several locations can be marked in a few minutes without damage to the tissue or the electrode. In 21 cats all of the 62 marked spots were found. In 16 peripheral (depth 50-150 micrometers) locations the PO2 averaged 101 Torr and in 46 deep locations 73 Torr. This technique is applicable to glass micropipettes and is a unique tool in correlating the structure and function of various tissues. PMID:7429916

  20. Effects of Calcium Phosphate Nanoparticles on Ca-PO4 Composite

    PubMed Central

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

    2009-01-01

    Nano-particles of dicalcium phosphate anhydrous (DCPA) were synthesized for the first time. The objectives of this study were to incorporate DCPA nano-particles into resin for Ca-PO4 release to combat dental caries, and to investigate the filler level effects. Nano-DCPA and nano-silica-fused silicon nitride whiskers at a 1:1 ratio were used at filler mass fractions of 0–75%. The flexural strengths in MPa (mean ± SD; n = 6) of DCPA-whisker composites ranged from (106 ± 39) at 0% fillers to (114 ± 23) at 75% fillers, similar to (112 ± 22) of a non-releasing composite (TPH) (p > 0.1). The composite with 75% fillers in a NaCl solution (133 mmol/L, pH = 7.4, 37°C) yielded a Ca concentration of (0.65 ± 0.02) mmol/L and PO4 of (2.29 ± 0.07) mmol/L. Relationships were established between ion-release and DCPA volume fraction VDCPA: Ca = 4.46 VDCPA1.6, and PO4 = 66.9 VDCPA2.6. Nano-DCPA-whisker composites had high strength and released high levels of Ca-PO4 requisite for remineralization. These new nano-composites could provide the needed combination of stress-bearing and caries-inhibiting capabilities. PMID:17384036

  1. 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.

  2. Synthesis, characterization and observation of antisite defects in LiNiPO4 nanomaterials.

    PubMed

    Devaraju, Murukanahally Kempaiah; Truong, Quang Duc; 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 °C 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. 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

  4. Computational research on memory effects in AlPO4-5 nanoporous material

    NASA Astrophysics Data System (ADS)

    Gulín-González, J.; Demontis, P.; Navas Conyedo, E.; Suffritti, G. B.

    2012-06-01

    Reversible amorphization and memory effects of both dense and open frameworks have received a great attention due to their prospective industrial applications. In this paper, the results of a computational study related to phase transition and memory effects in AlPO4-5 nanoporous material at high external pressure is presented. The behavior of the AlPO4-5 unit cell at high external pressures was studied by energy minimization techniques using classical potentials. A combination of interatomic potentials was used to describe the crystalline structure of the aluminophosphate. According to simulation's result a decrease of crystalline order is observed at a pressure about 3.5 GPa. The behavior of the simulated infrared spectra of compressed structures is an unambiguous evidence of structural disorder. Also, an abrupt change in the slope of the unit cell volume vs. pressure curve was obtained. At P≤3.5 GPa the process was found reversible. Contrary to what has been reported in other aluminosilicate systems the final crystalline state of AlPO4-5 at the highest simulated pressure was not amorphous. According to our knowledge this is the first evidence of a reversible first-order crystal-crystal phase transition in AlPO- family materials. This result could be important in future industrial and catalytic applications of these materials.

  5. 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.

  6. 76 FR 40849 - Post Office (PO) Box Fee Groups for Merged Locations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-12

    ... Service, Domestic Mail Manual (DMM ) 508.4 to allow Post Office TM (PO) Box fee groups to be merged due to... (DMM), incorporated by reference in the Code of Federal Regulations. See 39 CFR 111.1. List of Subjects... Mail Manual (DMM) as follows: Mailing Standards of the United States Postal Service, Domestic...

  7. Preassembly-driven ratiometric sensing of H2PO4(-) anions in organic and aqueous environments.

    PubMed

    Gong, Wei-tao; Na, Duo; Fang, Le; Mehdi, Hassan; Ning, Gui-ling

    2015-02-21

    Gemini surfactant-like receptor is designed and synthesized. The special preassembly phenomenon of in a nonpolar solvent facilitates the novel ratiometric fluorescence sensing of H2PO4(-)via an anion-induced reassembly process in organic solvents and an anion-induced disassembly process in water. PMID:25563510

  8. 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.

  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. Negative thermal expansion in Th{sub 2}O(PO{sub 4}){sub 2}

    SciTech Connect

    Wallez, Gilles; Clavier, Nicolas; Dacheux, Nicolas

    2011-11-15

    Highlights: {yields} Dithorium oxide phosphate shows a continuous negative thermal expansion over a 600 {sup o}C range. {yields} Negative expansion arises from oxygen rocking and cations repulsions. {yields} Big and high-charge thorium IV appears ideal for generating negative expansion. -- Abstract: High temperature X ray diffraction performed on recently discovered orthorhombic Th{sub 2}O(PO{sub 4}){sub 2} shows a continuous linear thermal contraction (-1.6 x 10{sup -6} {sup o}C{sup -1}) in 20-600 {sup o}C range and a near-zero expansion at higher temperatures resulting from a dual structural deformation involving oxygen oscillations and inter-cations repulsions. Although similar mechanisms were observed in isotypic Zr{sub 2}O(PO{sub 4}){sub 2} (+1.5 x 10{sup -6} {sup o}C{sup -1}) and U{sub 2}O(PO{sub 4}){sub 2} (-1.4 x 10{sup -6} {sup o}C{sup -1}), those observed in Th{sub 2}O(PO{sub 4}){sub 2} are particularly intense because of the high ionic radius of tetravalent thorium.

  11. 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.

  12. Low Temperature VOC Combustion Over Manganese, Cobalt and Zinc AlPO{sub 4} Molecular Sieves

    SciTech Connect

    Szostak, R.

    1997-03-31

    The objective of this project is to prepare manganese, cobalt and zinc containing AlPO{sub 4} molecular sieves and evaluate their catalytic activities for the removal of low levels of volatile organic compounds (VOCs) from gas streams. This report highlights our research activities for period October 1,1996 to March 31, 1997.

  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. [The management of nurses' training school of PO KU NYO KWAN (1903~1933)].

    PubMed

    Lee, Bang-weon

    2011-12-31

    This paper aims to examine the establishing background, curriculum and organization of personnel of Nurses' Training School of PO KU NYO KWAN(Caring For and Saving Woman's Hospital), the first nurses' training school in Korea. It is attempt to richen Korean medical history by the historical approach to modern nurses' training institution in Korea. PO KU NYO KWAN, the first women's hospital in Korea was established in 1887 by Metta Howard, who was sent by the Woman's Foreign Missionary Society of Northern Methodist Episcopal Church. Women doctors who were responsible for PO KU NYO KWAN felt the necessity of the professional nurses' training institution during performing medical activity with the help of Korean assistants and asked the Woman's Foreign Missionary Society to establish the nurses' training institution consistently. Margaret J. Edmunds was sent with the mission to establish nurses' training school in PO KU NYO KWAN. She made regulations for establishing nurses' training school, translated 'nurse' into "Gan-ho-won" in Korean language, made nurses' uniforms and prepared textbooks. Nurses' Training School of PO KU NYO KWAN was opened late December in 1903 officially. It had various subjects relating nursing in curriculum. The faculty of it was mainly comprised of medical missionaries of Methodist Episcopal Church and Presbyterian Church. Also the graduates of Severance Medical School and the graduates and students of Nurses' Training School of PO KU NYO KWAN participated its curriculum as teaching staff. In late 1920, Joseon Nurses Association (Joseon ganhobuhoe) discussed about the requirements for admission and the course of study for missionary nurses training school. After this process, students who were qualified for high-level class could have admission for Nurses' Training School of PO KU NYO KWAN. Medical staff belonged to East Gate Hospital and the graduates of Ewha College taught classes in it. First capping ceremony was held on January 25, 1906

  16. 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. PMID:18371988

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. Particle Scavenging and Tidal Exchange of Po-210 and Th-234 in a Mesotidal Embayment in Southern California

    NASA Astrophysics Data System (ADS)

    Peng, J.; Ku, T.; Luo, S.

    2002-12-01

    San Diego Bay (SDB) is a semi-closed shallow embayment that sustains semidiurnal tides and continuous tidal flows. We measured Po-210 and Th-234 activities in water samples collected from across north SDB, coastal waters immediately outside SDB, and from several rivers in the vicinity of SDB. A station in north SDB was sampled multiple times during a complete flooding-ebbing cycle. The major findings are as follows. 1) Compared to the outer sea, SDB water has much higher Th-234 deficiency (1.3-2.0 dpm/l, vs. 0.4-0.8dpm/l for outer sea) and considerably lower Po-210 activities (averaging 0.05dpm/l vs. 0.07dpm/l for outer sea) due to stronger particle scavenging. There is higher particulate Po-210 vs. total Po-210 ratio in SDB water (68%, vs. 34% for outer sea). 2) Inside SDB, an increasing Po-210 activities towards the bay mouth clearly indicates the effect of tidal exchange. Po-210 activity near the Bay mouth exceeds that of the outer sea due to higher particulate Po-210, which may come from tidal-induced sediment resuspension. 3) Rivers flowing into or near SDB have 8-12 times higher Po-210 activities than the bay water. But the input of Po-210 to SDB from rivers should be insignificant because of the negligible flow in the dry season. 4) In a tidal cycle, both Po-210 and Th-234 activities in North Bay covary with tidal pattern, which can be readily explained by the exchange between two waters inside and outside SDB with distinct TSS levels and Po-210/Th-234 activities. Sediment resuspension plays an important role during the peak tidal flow, resulting in an asymmetrical time-evolution curve of Po-210/Th-234 activities. These observations correspond well with our previous finding of systematic variations of Po-210 and Th-234 activities in water and sediment columns across SDB. This study manifests the significance of hydrodynamic processes such as advection, mixing and particle movement in the study of geochemistry of particle-reactive radionuclides in a tidal

  2. 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.

  3. 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

  4. 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

  5. Caspase-1-Like Regulation of the proPO-System and Role of ppA and Caspase-1-Like Cleaved Peptides from proPO in Innate Immunity

    PubMed Central

    Jiravanichpaisal, Pikul; Nakamura, Seiko; Tassanakajon, Anchalee; Söderhäll, Irene; Söderhäll, Kenneth

    2014-01-01

    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. PMID

  6. 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.

  7. 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

  8. Electrochemical properties of magnesium doped LiFePO{sub 4} cathode material prepared by sol–gel method

    SciTech Connect

    Zhao, Xiaohui; Baek, Dong-Ho; Manuel, James; Heo, Min-Yeong; Yang, Rong; Ha, Jong Keun; Ryu, Ho-Suk; Ahn, Hyo-Jun; Kim, Ki-Won; Cho, Kwon-Koo; Ahn, Jou-Hyeon

    2012-10-15

    Magnesium doped Li{sub 1−2x}Mg{sub x}FePO{sub 4}/C (x = 0.00, 0.01, 0.03, 0.05) cathode materials were synthesized by sol–gel method, and the effect of magnesium doping as well as its content on the electrochemical properties for lithium batteries was also investigated{sub .} Their morphology was studied with field emission scanning electron microscope and Li{sub 1−2x}Mg{sub x}FePO{sub 4} materials showed the olivine phase without impurities. The thin carbon layer of Li{sub 1−2x}Mg{sub x}FePO{sub 4}/C was confirmed by high resolution transmission electron microscopy. The magnesium doped Li{sub 1−2x}Mg{sub x}FePO{sub 4}/C particles were smaller than those undoped. The Li{sub 1−2x}Mg{sub x}FePO{sub 4}/C materials showed better cycling behavior than undoped LiFePO{sub 4}, especially at high C-rate in which Li{sub 0.94}Mg{sub 0.03}FePO{sub 4}/C composition exhibited the best electrochemical properties.

  9. Structure- and temperature-sensitive photoluminescence in a novel phosphate red phosphor RbZnPO4:Eu(3.).

    PubMed

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

    2015-09-28

    A novel phosphate RbZnPO4 has been developed for the first time and the characteristic crystal structure of RbZnPO4 has been investigated in detail, based on the Fourier transform infrared reflection spectra and the structure refinement of X-ray diffraction data. After doping with Eu(3+),RbZnPO4:Eu(3+) shows distinctive deep red emission with dominating peaks at 596 and 701 nm. To provide a reasonable explanation for the relationship between photoluminescence and structure, the photoluminescence property has been discussed by analyzing the particular local ligand environment and site occupation of Eu(3+) in RbZnPO4. More interestingly, temperature-sensitive emission behavior was found in RbZnPO4:Eu(3+). Through the synthetical analysis of the configurational coordinate diagram, the charge compensation experiment and the CASTEP band structure calculation, a complex underlying mechanism is proposed to explain the abnormal temperature-sensitive emission behavior in RbZnPO4:Eu(3+). The mechanism could be helpful for better understanding the thermal quenching process of Eu(3+) in RbZnPO4 and also as a reference in some other temperature-sensitive phosphors. PMID:26287663

  10. 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.

  11. Preparation of V-Doped LiFePO4/C as the Optimized Cathode Material for Lithium Ion Batteries.

    PubMed

    Sun, Pingping; Zhang, Haiyang; Shen, Kai; Fan, Qi; Xu, Qingyu

    2015-04-01

    LiFe1-x,Vx,PO4/C composites were synthesized by solid state reaction. The effect of carbon coating and V doping on the performance of LiFePO4 has been systematically investigated by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), charge/discharge and cyclic voltammetry (CV) measurement. The results show that carbon coating and proper amount of V incorporation do not significantly change the host crystal structure of LiFePO4, while the electrochemical performance of LiFePO4 can be significantly improved. Particularly, the LiFe0.96V0.04PO4/C exhibits the best performance with a specific discharge capacity of 105.5 mA h/g at 5.0 C, 90.3 mA h/g at 10 C and 66.7 mA h/g at 30 C with stable cycle performance, which is significantly improved compared with the pure LiFePO4/C. The cyclic voltammograms result reveals that V doping could decrease the resistance of LiFePO4/C composite electrode drastically and improve its reversibility. PMID:26353479

  12. 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

  13. Mechanical properties and in vitro bioactivity of Ca5(PO4)2SiO4 bioceramic.

    PubMed

    Lu, Wenhao; Duan, Wei; Guo, Yaping; Ning, Congqin

    2012-02-01

    Pure Ca(5)(PO(4))(2)SiO(4) bioceramic was first prepared by a sol-gel method using triethyl phosphate, tetraethoxysilane, and calcium nitrate tetrahydrate as original materials. Simulated body fluid (SBF) immersion tests revealed that Ca(5)(PO(4))(2)SiO(4) samples had a greater in vitro apatite-forming ability than hydroxyapatite (HA). After soaking Ca(5)(PO(4))(2)SiO(4) samples in the SBF for 1 day, bone-like apatite precipitated on the surfaces and the apatite layer became thicker with increasing the soaking time. However, few bone-like apatites precipitated on the HA samples even after soaking in the SBF for 7 days. The good in vitro bioactivity of Ca(5)(PO(4))(2)SiO(4) samples was attributed to the silanol (Si-OH) groups and greater solubility of Ca(5)(PO(4))(2)SiO(4). In addition, hot-pressed Ca(5)(PO(4))(2)SiO(4) ceramic exhibited lower bending strength and elastic modulus than hot-pressed HA, since the former had a lower relative density than the latter. The results have shown that Ca(5)(PO(4))(2)SiO(4) is a potential candidate material for bone repair. PMID:20876633

  14. The activity concentration of 210Po in Romanian commercial cigarettes and the radiation exposure estimation derived from their regular consumption.

    PubMed

    Begy, R Cs; Somlai, J; Kovacs, T; Dumitru Rusu, O A; Cosma, C

    2013-11-01

    Due to the relatively high activity concentrations of (210)Po that are found in tobacco, cigarette smoking has been found to be the principal pathway of the intake of this radionuclide. The (210)Po concentrations in the lung tissues may contribute significantly to an increase in the internal radiation dose and in the number of instances of lung cancer observed among smokers. The study of (210)Po in tobacco is required due to its potential for human radiation exposure through ingestion and inhalation. The risk factor caused by (210)Po in Romanian commercial cigarettes is not yet evaluated. Ten of the most frequently smoked brands of cigarettes sold in Romania were investigated in this work for this purpose. The activity concentration of (210)Po was determined by alpha spectrometry using a PIPS detector after chemical leaching and spontaneous deposition of (210)Po on a stainless steel disc from diluted HCl solution. The samples were spiked with (209)Po for chemical recovery calculation. The (210)Po activity concentrations of the measured types of cigarettes ranged from 4.65 to 10.22 mBq sample(-1) and the resulted average concentration of (210)Po isotopes is 8.35±0.80 mBq cigarette(-1) (the errors form a 2σ interval of confidence). When comparing the results of this study with the activity concentration values reported by other countries it was found that the results of this study are in the lower end of the world range. The estimation of this study shows that cigarette smokers, who are smoking one pack (20 cigarettes) per day, are exposed to an effective dose of 75.51 μSv y(-1). PMID:23651657

  15. Distribution of 210Pb and 210Po concentrations in wild berries and mushrooms in boreal forest ecosystems.

    PubMed

    Vaaramaa, Kaisa; Solatie, Dina; Aro, Lasse

    2009-12-15

    The activity concentrations and distribution of 210Pb and 210Po in wild berries and edible mushrooms were investigated in Finnish forests. The main study areas were located in Scots pine (Pinus sylvestris L.) forests in southern and northern Finland. The activity concentrations of 210Pb and 210Po in blueberry (Vaccinium myrtillus L.) and lingonberry (Vaccinium vitis-idaea L.) samples decreased in the order: stems>leaves>berries (i.e. fruits). The activity ratios of 210Po/210Pb in the wild berry samples were mainly higher than one, indicating elevated activity concentrations of polonium in the samples. In mushrooms the activity concentrations of 210Pb and especially 210Po were higher than in fruits of the wild berries. The highest activity concentration of 210Pb was detected in Cortinarius armillatus L. (16.2 Bq kg(-1) d.w.) and the lowest in Leccinum vulpinum L. (1.38 Bq kg(-1) d.w.). The 210Po activity concentrations of the whole fruiting bodies ranged from 7.14 Bq kg(-1) d.w. (Russula paludosa L.) to 1174 Bq kg(-1) d.w. (L. vulpinum L.). In general, the highest activity concentrations of 210Po were recorded in boletes. The caps of mushrooms of the Boletaceae family showed higher activity concentrations of 210Po compared to the stipes. In most of the mushrooms analyzed, the activity concentrations of 210Po were higher than those of 210Pb. 210Po and 210Pb dominate the radiation doses received via ingestion of wild berries and mushrooms in northern Finland, while in southern Finland the ingested dose is dominated by 137Cs from the Chernobyl fallout. PMID:19800659

  16. Behavior of LiFe1-yMnyPO4/C cathode materials upon electrochemical lithium intercalation/deintercalation

    NASA Astrophysics Data System (ADS)

    Novikova, Svetlana; Yaroslavtsev, Sergey; Rusakov, Vyacheslav; Chekannikov, Andrey; Kulova, Tatiana; Skundin, Alexander; Yaroslavtsev, Andrey

    2015-12-01

    LiFe1-yMnyPO4/C (y = 0-0.3) nanocomposites are prepared by the sol-gel method, and their properties are characterized with the use of the XRD analysis, SEM, impedance spectroscopy, charge/discharge tests, and Mössbauer spectroscopy. The samples with a low manganese content, LiFe1-yMnyPO4 (y = 0.1, 0.2) are characterized by an increased conductivity. In LiFe1-yMnyPO4 (x = 0.1-0.3), electrochemical lithium deintercalation/intercalation proceeds in two stages which due to the subsequent oxidation/reduction of iron and manganese ions. The LiFe1-yMnyPO4/С (y = 0.1, 0.2) samples show enhanced charge/discharge capacity, especially, at high current density (for LiFe0.9Mn0.1PO4/C, the discharge capacity is equal to 142 and 55 mAh g-1 at a current density of 20 and 1600 mA g-1, respectively). Mn2+ ↔ Mn3+ transition in LiFe1-yMnyPO4 proceeds via the solid solutions formation under gradual changes in the potential. For LiFe0.7Mn0.3PO4, oxidation and reduction of iron ions follow the same scenario. According to the Mössbauer spectroscopy data, manganese is orderly distributed in LixFeIII1-yMnyPO4: iron contains not more than one manganese cation in its nearest neighborhood. Moreover, combination of the Mössbauer spectroscopy and X-ray analysis data indicates that, in the interval where solid solutions exist in LixFe0.7Mn0.3PO4, the regions with an inhomogeneous distribution of divalent and trivalent manganese ions are formed.

  17. 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

  18. Eye position influence on the parieto-occipital area PO (V6) of the macaque monkey.

    PubMed

    Galletti, C; Battaglini, P P; Fattori, P

    1995-12-01

    The aim of this work was to study the effect of eye position on the activity of neurons of area PO (V6), a cortical region located in the most posterior part of the superior parietal lobule. Experiments were carried out on three awake macaque monkeys. Animals sat in a primate chair in front of a large screen, and fixated a small spot of light projected in different screen locations while the activity of single neurons was extracellularly recorded. Both visual and non-visual neurons were found. About 48% of visual and 32% of non-visual neurons showed eye position-related activity in total darkness, while in approximately 61% of visual response was modulated by eye position in the orbit. Eye position fields and/or gain fields were different from cell to cell, going from large and quite planar fields up to peak-shaped fields localized in more or less restricted regions of the animal's field of view. The spatial distribution of fixation point locations evoking peak activity in the eye position-sensitive population did not show any evident laterality effect, or significant top/bottom asymmetry. Moreover, the cortical distribution of eye position-sensitive neurons was quite uniform all over the cortical region studied, suggesting the absence of segregation for this property within area PO (V6). In the great majority of visual neurons, the receptive field 'moved' with gaze according to eye displacements, remaining at the same retinotopic coordinates, as is usual for visual neurons. In some cases, the receptive field did not move with gaze, remaining anchored to the same spatial location regardless of eye movements ('real-position cells'). A model is proposed suggesting how eye position-sensitive visual neurons might build up real-position cells in local networks within area PO (V6). The presence in area PO (V6) of real-position cells together with a high percentage of eye position-sensitive neurons, most of them visual in nature, suggests that this cortical area is

  19. Pulse oximetry versus transcutaneous pO2 in sick newborn infants.

    PubMed

    Wimberley, P D; Helledie, N R; Friis-Hansen, B; Fogh-Andersen, N; Olesen, H

    1987-01-01

    A pulse oximeter (Ohmeda Biox 3700) and two transcutaneous systems (Radiometer TCM3) were applied simultaneously to 18 newborn infants with respiratory insufficiency. All infants had either an umbilical catheter placed in the mid thoracic aorta or a radial artery catheter. The average monitoring time was 2 hours. Arterial blood pO2, pCO2 and pH (Radiometer ABL300), arterial sO2, HbCO and metHb (Radiometer OSM3), erythrocyte 2,3 DPG concentration, and fetal hemoglobin fraction (alkali denaturation kinetic method) were measured. Using arterial sO2 and pO2 as reference, the analytical bias of pulse oximetry (-0.5 +/- 1.0%, mean +/- 1 SD) corresponded in magnitude, when converted to pO2, to that of transcutaneous - pO2 (0.6 +/- 1.4 kPa for combined O2-CO2 electrode and -0.1 +/- 2.3 kPa for single O2 electrode). Transcutaneous pCO2 showed the smallest bias (0.3 +/- 0.3 kPa). Both pulse oximetry and transcutaneous pO2 electrodes were good as trend monitors detecting rapid changes in the infants' oxygenation status. The pulse oximeter offers certain advantages in not requiring calibration or heating. The variations in the levels of fetal hemoglobin fraction (44 to 97%), pH (7.27 to 7.49), pCO2 (3.3 to 6.8 kPa) and 2,3 diphosphoglycerate concentration (1.6 to 5.9 mmol/l) between the infants studied, resulted in a variable pO2-sO2 relation (p50 2.5 to 3.5 kPa). This presents difficulties in interpreting sO2 values in sick newborn infants, and we therefore recommend caution in using a pulse oximeter to apply strict limits for avoiding hypoxia and hyperoxia in this population. PMID:2453078

  20. The development of low cost LiFePO4-based high power lithium-ion batteries

    SciTech Connect

    Shim, Joongpyo; Sierra, Azucena; Striebel, Kathryn A.

    2003-11-25

    The cycling performance of low-cost LiFePO4-based high-power lithium-ion cells was investigated and the components were analyzed after cycling to determine capacity fade mechanisms. Pouch type LiFePO4/natural graphite cells were assembled and evaluated by constant C/2 cycling, pulse-power and impedance measurements. From post-test electrochemical analysis after cycling, active materials, LiFePO4 and natural graphite, showed no degradation structurally or electrochemically. The main reasons for the capacity fade of cell were lithium inventory loss by side reaction and possible lithium deposition on the anode.

  1. 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

  2. A novel nano structured LiFePO4/C composite as cathode for Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Zhang, Huang; Liu, Dong; Qian, Xiuzhen; Zhao, Chongjun; Xu, Yunlong

    2014-03-01

    A novel network LiFePO4/C composite was prepared by mixing precursor solution with carbon aerogel (CA) via a simple solution impregnation method, characterized by XRD, SEM, EDS and electrochemical analysis. The results revealed that the LiFePO4 nanowire forming on the ektexine of CA intertwined with LiFePO4/CA particles and formed a special web structure. The initial discharge capacity was improved to be 139.3 mAh g-1 at 10 C and the capacity retention is near 100% after 50 cycles. The web structure could improve electron transport and electrochemical activity effectively.

  3. Experimental and theoretical study of mechanoluminescence and lyoluminescence of Li3 PO4 : RE (RE = Dy and Tb) phosphors.

    PubMed

    Sahu, A K; Kadukar, Monali R; Chowdhary, P S; Nayar, V; Dhoble, S J

    2014-12-01

    Li3 PO4 phosphors prepared by solid-state diffusion technique and lyoluminescence (LL) as well as mechanoluminescence (ML) studies are reported. Dy- and Tb-activated phosphors show dosimetric characteristics using LL and ML techniques. The energy levels and hence trapping and detrapping of charge carriers in the material can be studied using ML. Li3 PO4 phosphor can be used in the dosimetric applications for ionizing radiation. By using the LL technique, the LL characteristics of Li3 PO4 may be useful for high radiation doses. We also report a more detailed theoretical understanding of the mechanism of LL and ML. PMID:24760580

  4. 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.

  5. Sr2Cu(PO4)2 and Ba2Cu(PO4)2 as quasi-one-dimensional spin-1/2 Heisenberg antiferromagnet

    NASA Astrophysics Data System (ADS)

    Haque, Md. Mahfoozul; Ahsan, M. A. H.

    2016-03-01

    Using magnetic exchange couplings for antiferromagnets Sr2Cu(PO4)2 and Ba2Cu(PO4)2, estimated independently by Johannes (2006 [1]) and Salunke (2007 [2]), we present model calculations via exact diagonalization for several lattices of 24 and 16 spins by calculating experimentally accessible quantities like spin-spin correlation, the antiferromagnetic order-parameter, entropy-density, specific-heat and z-component of the magnetic susceptibility using up to 15 low-lying eigenstates. From our calculation, the ratio of critical entropy and mean-field critical entropy comes out to be ∼ 0.492(7). The slope of the specific heat curve at low temperatures is found to be 2 / 3. The peak value of z-component of the magnetic susceptibility versus temperature curve turns out to be 1/3 χ ∼ 0.05 . Our results favor the conclusion that these magnetic compounds are indeed quasi-one-dimensional antiferromagnets.

  6. Investigation of the physical-mechanical properties of Eudragit(®) RS PO/RL PO and their mixtures with common pharmaceutical excipients.

    PubMed

    Dave, Vivek S; Fahmy, Raafat M; Hoag, Stephen W

    2013-07-01

    Ammonio methacrylate copolymers Eudragit(®) RS PO and Eudragit® RL PO have found widespread use as key components in various types of extended release solid dosage forms. The deformation behavior of neat polymers and binary mixes was evaluated using Heckel Analysis, strain rate sensitivity, work of compaction and elastic recovery index. Additionally, the compact forming ability of neat materials and binary mixes were evaluated by analyzing their tabletability, compressibility and compactibility profiles. The Heckel analysis of both polymers exhibited a speed-sensitive deformation behavior typical to plastic materials. The yield values of the binary mixes of the polymers with microcrystalline cellulose revealed a linear relationship with the weight fractions of individual components. The yield values of binary mixes of both the polymers with dibasic calcium phosphate exhibited slight negative deviations from linearity. Both polymers exhibited axial relaxation after ejection typical of viscoelastic materials, as measured by the elastic recovery index values. The work of compaction and the elastic recovery index values of the binary mixtures were found to be linearly related to the weight fractions of the individual components thus, confirming ideal mixing behavior based on the composition. Addition of microcrystalline cellulose to both polymers significantly improved their tabletability and compactibility. The tensile strengths of the compacts prepared with neat materials and binary mixes with microcrystalline cellulose, dibasic calcium phosphate and lactose were the function of their solid fraction and independent of the tableting speeds tested; thus, validating compactibility as a reliable parameter in predicting acceptable tablet properties. PMID:22994144

  7. Plutonium-239, /sup 240/Pu and /sup 210/Po contents of tobacco and cigarette smoke

    SciTech Connect

    Mussalo-Rauhamaa, H.; Jaakkola, T.

    1985-08-01

    The /sup 239/Pu and /sup 240/Pu found in the environment has mainly been produced by atmospheric nuclear tests. The accumulation of fallout Pu in man from inhalation and ingestion and its distribution in the body has previously been studied. Information about the accumulation is needed because of the expanding production of this highly radiotoxic substance. In the present work the Pu content of tobacco and cigarette smoke was determined to evaluate the contribution of smoking to total Pu intake by man. For comparison the /sup 210/Po content of tobacco and smoke were analyzed. The release of /sup 210/Po in tobacco smoke and the radiation dose for man have been widely studied because of the high incidence of lung cancer among smokers.

  8. 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

  9. Characterization of Se-loaded molecular sieves A, X, Y, AlPO-5, and mordenite

    SciTech Connect

    Parise, J.B.; MacDougall, J.E.; Herron, N.; Farlee, R.; Sleight, A.W.; Ying Wang; Bein, T.; Moller, K.; Moroney, L.M.

    1988-01-27

    Selenium has been successfully loaded into molecular sieves A, X, Y, AlPO-5, and mordenite, and the products were characterized by using EXAFS, solid-state NMR, and diffuse-reflectance techniques. This study reveals selenium is predominantly of the trigonal (helical chains) form in all but the A sample, where only the Se/sub 8/-crown ring form is found. A mixture of allotropes and helical chains occupy the large 3D-pore and channel systems of molecular sieves X and Y; however, a single, probably fixed-pitch helical-chain allotrope occupies the more constrained 12-membered-ring channels found in mordenite and AlPO-5. The high degree of order in these last two sieves is reflected in a strong second-shell feature in the EXAFS spectra. 22 refs., 12 figs., 3 tabs.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. A Novel Open-Framework Cerium Phosphate Fluoride: (NH 4)[Ce IVF 2(PO 4)

    NASA Astrophysics Data System (ADS)

    Yu, Ranbo; Wang, Dan; Takei, Takahiro; Koizumi, Hitoshi; Kumada, Nobuhiro; Kinomura, Nobukazu

    2001-02-01

    A novel open-framework cerium phosphate fluoride, (NH4)[CeIVF2(PO4)], has been synthesized under hydrothermal conditions and characterized by means of single-crystal X-ray diffraction, ion chromatography analysis, and thermal analysis. The compound crystallizes in the monoclinic space group P21/m(No. 11), with a=6.660(2), b=5.875(2), c=7.177(3) Å, β=114.31(2)°, and V=255.9(2) Å3 (R=0.039 and Rw=0.045). In this compound, the cerium-centered CeO4F4 polyhedra link via Ce2F2 rings to form corrugated chains along the b axis of the structure. These are tetrahedrally connected via PO4 groups to create the three-dimensional network with a one-dimensional channel. NH+4 cations are accommodated at the intersection of the channels.

  15. Reduction of acetophenones over Pd/AlPO[sub 4] catalysts. Linear free energy relationship (LFER)

    SciTech Connect

    Aramendia, M.; Borau, V.; Gomez, J.F.; Jimenez, C.; Marinas, J.M. ); Herrera, A. )

    1993-04-01

    The authors studied the reduction of variously substituted acetophenones over Pd/AlPO[sub 4], Pd/AlPO[sub 4]-SiO[sub 2], and Pd/SiO[sub 2] catalysts containing 3% Pd by weight. After the catalysts were characterized texturally and kinetically, they were used to reduce the different acetophenones at various temperatures under the same reaction conditions. The results correlate with the Hammett equation quite well, and the reaction was found to feature different sensitivity to electron-withdrawing (0.05 < [rho] < 0.20) and electron-releasing substituents (0.76 < [rho] < 1.37). On the other hand, a compensating effect was also found to occur, so the reaction mechanism can be assumed to be the same for every substrate. The reductions probably do not take place via enol forms of the acetophenone. The reaction rate decreases with increasing solvent polarity. 44 refs., 5 figs., 4 tabs.

  16. Ca3 (PO4 )2 :Eu3+ phosphor preparation with different morphologies and their fluorescence properties.

    PubMed

    Zhou, Xiaochun; Wang, Xiaojun

    2014-03-01

    Ca3(PO4)2:Eu(3+) phosphor was prepared using a facile chemistry method in the presence of surfactants. The effects of surfactants on the morphology and photoluminescence properties of Ca3(PO4)2:Eu(3+) phosphor were investigated. The morphology of the phosphor was significantly influenced by the surfactants employed. When nonionic surfactant glyceryl monostearate and anionic surfactant sodium dodecylbenzene sulfonate were employed, the phosphor powders are composed of a large number of homogeneous spherical particles with sizes of 0.3-0.6 µm and 2-3 µm, respectively. By contrast, when cationic surfactant cetyltrimethylammonium bromide was used, the morphology of the phosphor is completely different. The product is an excellent cuboid, and the phosphor prepared with 2.5 mmol cetyltrimethylammonium bromide showed higher luminescent intensity than phosphors prepared with the other two types of surfactants. PMID:23616256

  17. Spectroscopic characterizations of Er doped LaPO4 submicron phosphors prepared by homogeneous precipitation method

    NASA Astrophysics Data System (ADS)

    Saltmarsh, N.; Kumar, G. A.; Kailasnath, M.; Shenoy, Vittal; Santhosh, C.; Sardar, D. K.

    2016-03-01

    Hexagonal shaped LaPO4 submicron particles doped with various concentrations of Er were successfully prepared by homogenous precipitation method using metal nitrates and ammonium phosphate. Particles of approximate particle size 125 nm and size distribution of 85 nm are obtained with good crystallinity. After heat treatment at 1200 °C for 2 h, the particles are characterized for their various optical properties such as absorption, emission, fluorescence decay and optical band gap. Optical absorption and emission data are numerically analyzed with the help of Judd-Ofelt model to evaluate various radiative spectral properties such as radiative decay rates, radiative quantum yield, emission cross-section and fluorescence branching ratios of various emission transitions. Though the radiative quantum yield of 1554 nm emission approaches the theoretical limit of 100%, the experimentally measured quantum yield is only 11% at 12 W/cm2 at 980 nm excitation power density in 2% Er doped LaPO4.

  18. 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.

  19. 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

  20. 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.

  1. Electrical properties and conduction mechanism of the NaMg4(PO4)3 compound

    NASA Astrophysics Data System (ADS)

    Karray, M.; Louati, B.; Guidara, K.; Gargouri, M.

    2016-07-01

    The NaMg4(PO4)3 phosphor was prepared by the conventional high-temperature solid-state reaction. The phase formation of the compound was confirmed by the powder X-ray diffraction. Electrical properties of the compound have been studied using complex impedance spectroscopy in the frequency range 209 Hz-1 MHz and temperature range 648-712 K. The AC conductivity for grain contribution was interpreted using the universal Jonscher's power law. The temperature dependence of frequency exponent s was investigated to understand the conduction mechanism in NaMg4(PO4)3 compound. The non-overlapping small polaron tunneling model can explain the temperature dependence of the frequency exponent, and it was a closely good model to describe the dominant conduction mechanism.

  2. 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

  3. 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.

  4. Electric dipole moment in KH2PO4 systematically modified by proton irradiation

    NASA Astrophysics Data System (ADS)

    Jung Kweon, Jin; Eui Lee, Cheol; Noh, S. J.; Kim, H. S.

    2012-01-01

    We have carried out an impedance spectroscopy study on a series of proton-irradiated KH2PO4 (KDP) systems. A systematic modification was observed in the transverse dipole moment of the proton-irradiated KDP systems, associated with hydrogen-ion displacements, as obtained from dielectric constant measurements by using a mean-field approximation. Besides, intercorrelation of the charge transport with the dielectric properties was revealed, both having closely to do with the hydrogen-bond modification.

  5. Charge dynamics in KH2PO4 systematically modified by proton irradiation

    NASA Astrophysics Data System (ADS)

    Jung Kweon, Jin; Won Lee, Kyu; Lee, Kwang-Sei; Oh, In-Hwan; Eui Lee, Cheol

    2011-08-01

    Our systematic study employing high-resolution nuclear magnetic resonance measurements shows that the hydrogen bonds and proton transport in the KH2PO4 (KDP) system may be tuned sensitively by proton irradiation. In particular, the hydrogen-bond length in KDP increased by a properly chosen dose of proton irradiation is shown to give rise to a minimum in the activation energy of proton hopping in the hydrogen-bond direction.

  6. 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

  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. Charge dynamics in KH{sub 2}PO{sub 4} systematically modified by proton irradiation

    SciTech Connect

    Kweon, Jin Jung; Lee, Kyu Won; Lee, Cheol Eui; Lee, Kwang-Sei; Oh, In-Hwan

    2011-08-15

    Our systematic study employing high-resolution nuclear magnetic resonance measurements shows that the hydrogen bonds and proton transport in the KH{sub 2}PO{sub 4} (KDP) system may be tuned sensitively by proton irradiation. In particular, the hydrogen-bond length in KDP increased by a properly chosen dose of proton irradiation is shown to give rise to a minimum in the activation energy of proton hopping in the hydrogen-bond direction.

  10. Oil Production from Yarrowia lipolytica Po1g Using Rice Bran Hydrolysate

    PubMed Central

    Tsigie, Yeshitila Asteraye; Wang, Chun-Yuan; Kasim, Novy S.; Diem, Quy-Do; Huynh, Lien-Huong; Ho, Quoc-Phong; Truong, Chi-Thanh; Ju, Yi-Hsu

    2012-01-01

    The purpose of this study was to produce microbial oil from Yarrowia lipolytica Po1g grown in defatted rice bran hydrolysate. After removing oil from rice bran by Soxhlet extraction, the bran is subjected to acid hydrolysis with various sulfuric acid concentrations (1–4% v/v), reaction times (1–8 h), and reaction temperatures (60–120°C). The optimal conditions for maximum total sugar production from the hydrolysate were found to be 3% sulfuric acid at 90°C for 6 h. Glucose was the predominant sugar (43.20 ± 0.28 g/L) followed by xylose (4.93 ± 0.03 g/L) and arabinose (2.09 ± 0.01 g/L). The hydrolysate was subsequently detoxified by neutralization to reduce the amount of inhibitors such as 5-hydroxymethylfurfural (HMF) and furfural to increase its potential as a medium for culturing Y. lipolytica Po1g. Dry cell mass and lipid content of Y. lipolytica Po1g grown in detoxified defatted rice bran hydrolysate (DRBH) under optimum conditions were 10.75 g/L and 48.02%, respectively. PMID:22496604

  11. 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.

  12. 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.

  13. 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.

  14. Equilibrium and kinetics studies of arsenate adsorption by FePO(4).

    PubMed

    Hamayun, M; Mahmood, T; Naeem, A; Muska, M; Din, S U; Waseem, M

    2014-03-01

    The present work is focusing on removal of arsenate from aqueous solution using FePO4. The equilibrium study regarding the removal of arsenic by FePO4 was carried out at 298, 308, 318 and 328K. Langmuir parameters were found to increase with the increase in temperature indicating that the adsorption is favorable at high temperature. Kinetic study of arsenate adsorption on FePO4 was also carried out at different temperatures and at pH 6 and 8. Different kinetic models were used to the kinetic data amongst which pseudo second order model was best fitted. The mechanism of the adsorption kinetics was investigated by employing intraparticle diffusion and Richenberg models. The energy of activation (Ea) was found to be 30 and 35.52kJmol(-1) at pH 6 and pH 8, respectively, suggesting chemisorption nature of the adsorption process. The negative entropic values of activation signified the existence of entropy barrier while the positive ΔG(#) values indicated the existence of energy barrier to be crossed over for the occurrence of a chemical reaction. Both the spectroscopic studies and increase in equilibrium pH reveal the anion exchange removal of arsenate from aqueous solution to the solid surface. PMID:24280053

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. Biological response to nonuniform distributions of (210)Po in multicellular clusters.

    PubMed

    Neti, Prasad V S V; Howell, Roger W

    2007-09-01

    Radionuclides are distributed nonuniformly in tissue. The present work examined the impact of nonuniformities at the multicellular level on the lethal effects of (210)Po. A three-dimensional (3D) tissue culture model was used wherein V79 cells were labeled with (210)Po-citrate and mixed with unlabeled cells, and multicellular clusters were formed by centrifugation. The labeled cells were located randomly in the cluster to achieve a uniform distribution of radioactivity at the macroscopic level that was nonuniform at the multicellular level. The clusters were maintained at 10.5 degrees C for 72 h to allow alpha-particle decays to accumulate and then dismantled, and the cells were seeded for colony formation. Unlike typical survival curves for alpha particles, two-component exponential dose-response curves were observed for all three labeling conditions. Furthermore, the slopes of the survival curves for 100, 10 and 1% labeling were different. Neither the mean cluster absorbed dose nor a semi-empirical multicellular dosimetry approach could accurately predict the lethal effects of (210)Po-citrate. PMID:17705637

  20. 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.

  1. 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.

  2. Partial characterisation of pediocin PO2 and comparison with nisin for biopreservation of meat products.

    PubMed

    Coventry, M J; Muirhead, K; Hickey, M W

    1995-07-01

    A plasmid associated bacteriocin (pediocin PO2) was isolated by ammonium sulphate precipitation from cell-free growth media and subsequent studies showed that the partially purified pediocin PO2 was most likely identical (molecular mass approximately 3200 daltons in size by SDS-PAGE, stable to low pH and heat at 121 degrees C for 15 min, inactivated by various proteolytic enzymes and resistant to treatment with a range of solvents, except 10% formaldehyde) to other pediocins (PA-1 and AcH) previously reported. The antagonistic spectrum of activity of pediocin PO2 was compared with nisin and showed a narrower host-range, but a much greater activity against Listeria species including strains of Listeria monocytogences, than did nisin. A rapid method of reflectance colorimetry was used to quantitate growth and acid production (as determined by the colour change in bromcresol purple) of Lactobacillus curvatus, added to a meat product model system. The combined effects of refrigeration temperature, microbial load and bacteriocin concentration were determined in the model over 15 days storage. Both nisin and pediocin demonstrated inhibitory activity against Lactobacillus curvatus in the model system. However, when bacteriocins were incorporated into a manufactured cooked meat product only low nisin activity and no pediocin activity was detected, after challenge of vacuum packaged slices of product with Lactobacillus curvatus, over a 21 day storage trial under refrigeration temperatures. PMID:7577353

  3. 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.

  4. 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.

  5. Prediction of a new crystalline lithium phosphorus oxynitride -- Li2PO2N

    NASA Astrophysics Data System (ADS)

    Holzwarth, N. A. W.; Du, Yaojun A.

    2010-03-01

    Lithium phosphorus oxynitride materials have been investigated for many years, especially in relation to the thin film electrolye LiPON, developed at Oak Ridge National Laboratory.footnotetext J. B. Bates et al, Solid State Ionics 53-56 647-654 (1992). We have carried out first principles simulations of related crystalline materials in an attempt to understand the sources of stability and mechanisms of Li ion conductivity in these materials. Starting with crystalline LiPO3 which has twisted phosphate chains,footnotetextE. V. Marashova, Crystallography Reports 46 942-946 (2001). we consider the possibility of modifying the structure by substituting N and Li for O. The optimized structures are computed to have regularized phosphate chains which form planar -P-N-P-N- backbones. To the best of our knowledge, the new predicted crystals, which we call s1-Li2PO2N with a 24 atom unit cell and s2-Li2PO2N with a 12 atom unit cell, have not yet been observed experimentally. We suggest several possible exothermic reaction pathways to synthesize these crystals.

  6. 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

  7. 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.

  8. NASA High Energy Space Science E/PO at SSU: Program Overview and Lessons Learned

    NASA Astrophysics Data System (ADS)

    Plait, P.; Cominsky, L.

    2003-12-01

    The NASA Education and Public Outreach (E/PO) Group at Sonoma State University is the lead institution for the E/PO of three high-energy space science missions: Swift, GLAST, and XMM-Newton. We have developed award-winning standards-based formal and informal educational activities (classroom exercises, inquiry-driven games, posters, etc.) for these missions, with many more coming soon. Our primary goal is to teach students about the high-energy end of the electromagnetic spectrum, and the astrophysical objects which emit in that energy range. We will present an overview of our group and our work. This includes our collaborations with other groups, getting mission scientists' input on the projects, and the lessons learned in making effective E/PO products that actually get used by teachers. We will also include a brief overview of the NASA Educator Ambassador program, a new highly-effective effort we have initiated to train top-notch educators from across the country to help us develop, test, and disseminate our products.

  9. Oil production from Yarrowia lipolytica Po1g using rice bran hydrolysate.

    PubMed

    Tsigie, Yeshitila Asteraye; Wang, Chun-Yuan; Kasim, Novy S; Diem, Quy-Do; Huynh, Lien-Huong; Ho, Quoc-Phong; Truong, Chi-Thanh; Ju, Yi-Hsu

    2012-01-01

    The purpose of this study was to produce microbial oil from Yarrowia lipolytica Po1g grown in defatted rice bran hydrolysate. After removing oil from rice bran by Soxhlet extraction, the bran is subjected to acid hydrolysis with various sulfuric acid concentrations (1-4% v/v), reaction times (1-8 h), and reaction temperatures (60-120°C). The optimal conditions for maximum total sugar production from the hydrolysate were found to be 3% sulfuric acid at 90°C for 6 h. Glucose was the predominant sugar (43.20 ± 0.28 g/L) followed by xylose (4.93 ± 0.03 g/L) and arabinose (2.09 ± 0.01 g/L). The hydrolysate was subsequently detoxified by neutralization to reduce the amount of inhibitors such as 5-hydroxymethylfurfural (HMF) and furfural to increase its potential as a medium for culturing Y. lipolytica Po1g. Dry cell mass and lipid content of Y. lipolytica Po1g grown in detoxified defatted rice bran hydrolysate (DRBH) under optimum conditions were 10.75 g/L and 48.02%, respectively. PMID:22496604

  10. 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.

  11. 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

  12. 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.

  13. Microwave Sintering and Optical Properties of Sm3+-Activated KSrPO4 Phosphors

    NASA Astrophysics Data System (ADS)

    Wu, Chun-Sen; Lin, Bor-Tsuen; Jean, Ming-Der

    2014-02-01

    The microwave sintering and photoluminescence properties of KSr1- x PO4: xSm3+ phosphors have been investigated. KSrPO4 phosphates activated by various concentrations of Sm3+ ions ( x = 0.007, 0.009, 0.01, 0.03) were microwave sintered at 1200°C for 3 h under air atmosphere. x-Ray diffraction patterns showed that all phosphor samples exhibited a single phase without any extraneous phases. Scanning electron microscopy images showed that the particle size increased with the Sm3+ concentration and that the particle morphology was fine and uniform. The photoluminescence results showed that a concentration quenching effect occurred when the concentration of Sm3+ ions reached x = 0.01. Decay time measurement results showed that the lifetime decreased gradually from 3.12 ms to 2.34 ms as the Sm3+ concentration increased. All the chromaticity ( x, y) values of the microwave-sintered KSrPO4:Sm3+ phosphors were located in the red region (0.57, 0.41).

  14. Ab initio study of phase stability of NaZr2(PO4)3 under pressure

    NASA Astrophysics Data System (ADS)

    Chinnappan, Ravi; Kaur, Gurpreet; Panigrahi, B. K.

    2016-05-01

    The elastic constants of NaZr2(PO4)3 were computed as a function of pressure through Density Functional Theory calculations. The behavior of elastic constants show that the rhombohedral (R-3c) NaZr2(PO4)3 becomes unstable above 8 GPa and is driven by softening of C44 through one of the Born stability criteria. High pressure equation of state and enthalpy show further that the ambient rhombohedral (R-3c)) NaZr2(PO4)3 transforms first to another rhombohedral (R3) phase and subsequently to LiZr2(PO4)3-type orthorhombic phase at pressures above 6 and 8 GPa respectively which are in agreement with recent X-ray diffraction study.

  15. A novel ZePoC encoder for sinusoidal signals with a predictable accuracy for an AC power standard

    NASA Astrophysics Data System (ADS)

    Vennemann, T.; Frye, T.; Liu, Z.; Kahmann, M.; Mathis, W.

    2015-11-01

    In this paper we present an analytical formulation of a Zero Position Coding (ZePoC) encoder for an AC power standard based on class-D topologies. For controlling a class-D power stage a binary signal with special spectral characteristics will be generated by this ZePoC encoder for sinusoidal signals. These spectral characteristics have a predictable accuracy within a separated baseband to keep the noise floor below a specified level. Simulation results will validate the accuracy of this novel ZePoC encoder. For a real-time implementation of the encoder on a DSP/FPGA hardware architecture a trade-off between accuracy and speed of the ZePoC algorithm has to be made. Therefore the numerical effects of different floating point formats will be analyzed.

  16. 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

  17. 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%.

  18. 210Pb and 210Po in fossil fuel combustion at the Šoštanj thermal power plant (Slovenia)

    NASA Astrophysics Data System (ADS)

    Vreček, P.; Benedik, L.

    2003-01-01

    The main aim of the present study was to evaluate 210Pb and 210Po emissions from the Šoštanj TPP and to evaluate their mass balance in unit 4. Samples of coal, fly ash, slag and flue gases were analysed for 210Pb and 210Po content. The results showed that these radionuclides are mostly concentrated in ash (71% and 81% for 210Pb and 210Po, respectively). Only a small part of the input activity was detected in flue gases. The activities of 210Pb and 210Po in unit 4 were from 1.1 to 2.7 Bq m-3 and from 0.37 to 0.56 Bq m-3, respectively. The mass balance of the two radionuclides in unit 4 show only 6 and 10% differences between the annual activities of the input and output samples.

  19. 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.

  20. Electrochemical and XPS study of LiFePO4 cathode nanocomposite with PPy/PEG conductive network

    NASA Astrophysics Data System (ADS)

    Fedorková, A.; Oriňáková, R.; Oriňák, A.; Kupková, M.; Wiemhöfer, H.-D.; Audinot, J. N.; Guillot, J.

    2012-08-01

    High performance PPy/PEG-LiFePO4 nanocomposites as cathode materials were synthesized by solvothermal method and simple chemical oxidative polymerization of pyrrole (Py) monomer on the surface of LiFePO4 particles. The samples were characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectrometry (XPS) and charge-discharge tests. PPyPEG hybrid layers decrease particle to particle contact resistance while the impedance measurements confirmed that the coating of PPy-PEG significantly decreases the charge transfer resistance of the electrode material. The initial discharge capacities of this sample at C/5 and 1C are 150 and 128 mAh/g, respectively. The results show that PPy/PEGLiFePO4 composites are more effective than bare LiFePO4 as cathode material.

  1. Investigation of spin ordering in antiferromagnetic Fe1-xMnxPO4 with Mössbauer spectroscopy

    NASA Astrophysics Data System (ADS)

    Jun Kwon, Woo; Wha Lee, Bo; Sung Kim, Chul

    2013-05-01

    We have investigated the spin ordering in Fe1-xMnxPO4, which is a possible cathode material for rechargeable lithium ion battery, with antiferromagnetic structure below Néel temperature (TN). The prepared Fe1-xMnxPO4 (x = 0.0, 0.1, and 0.3) samples have orthorhombic structures with space group of Pnma. These samples show the magnetic phase transition, caused by the strong crystalline field at the MO6 octahedral sites. According to the temperature dependence of magnetic susceptibility of Fe1-xMnxPO4, all samples show antiferromagnetic behaviors. The Néel temperature (TN) decreases from 114 K at x = 0.0 to 97 K at x = 0.3 with Mn concentrations. The magnetization of Fe1-xMnxPO4 decreases until the temperature reaches the spin-reorientation (TS) temperature, and then starts increasing as the temperature increases up to TN. The TS of the Fe1-xMnxPO4 were found to be 30, 27, and 24 K for x = 0.0, 0.1, and 0.3. In order to investigate the hyperfine interaction of Fe3+ ions in FeO6 octahedral sites, Mössbauer spectra of Fe1-xMnxPO4 have been taken at various temperatures from 4.2 to 295 K. The isomer shift (δ) values of the Fe1-xMnxPO4 were between 0.31 and 0.43 mm/s, indicating the high spin state of Fe3+ at all temperatures. The magnetic hyperfine field (Hhf) and electric quadrupole splitting (ΔEQ) values of Fe0.9Mn0.1PO4 at 4.2 K were determined to be Hhf = 498 kOe and ΔEQ = 2.1 mm/s. We have also observed the abrupt changes in Hhf and ΔEQ at 27 K for Fe0.9Mn0.1PO4, and decrease the value of TS of Fe1-xMnxPO4 with Mn concentrations. Our study suggests that these changes in Fe1-xMnxPO4 are originated from the strong electric crystalline field and spin-orbit coupling of FeO6 octahedral site.

  2. (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

  3. 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

  4. 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

  5. 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.

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

    SciTech Connect

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

    2012-03-15

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

  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. 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

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. '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. PMID:24502565

  16. Photoluminescence properties of a novel red emitting Ba10F2(PO4)6:Eu3+ phosphor

    NASA Astrophysics Data System (ADS)

    Peng, You-shun; Shi, Wei-wei; Han, Cong-lin; Kang, Yan-yan; Wang, Yan-su; Zhang, Zhi-wei

    2015-06-01

    A novel red-emitting phosphor Ba10F2(PO4)6:Eu3+ is synthesized by a high-temperature solid-state reaction. X-ray powder diffraction (XRD) analysis confirms the phase formation of Ba10F2(PO4)6:Eu3+ materials. The photoluminescence excitation (PLE) and emission (PL) spectra, the concentration dependence of the emission intensity, decay curves and Commission International de I'Eclairage (CIE) of the phosphors are investigated. It is observed that Ba10F2(PO4)6:Eu3+ phosphors exhibit two dominating bands situated at 591 and 616 nm, originating from the 5D0 → 7F1 and 5D0 → 7F2 transition of the Eu3+ ion, respectively. The decay time is also determined for various concentrations of Eu3+ in Ba10F2(PO4)6:Eu3+. Crystal lattice, PL spectra and decay time analysis indicate there exist two isolated Eu3+ crystallography sites in Ba10F2(PO4)6. The calculated color coordinates lie in the red region. Therefore, Ba10F2(PO4)6:Eu3+ phosphors may be good candidates for red components in near-UV (NUV) white LEDs.

  17. Photoluminescence properties of a novel red emitting Ba₁₀F₂(PO ₄)₆:Eu³⁺ phosphor.

    PubMed

    Peng, You-Shun; Shi, Wei-Wei; Han, Cong-Lin; Kang, Yan-Yan; Wang, Yan-Su; Zhang, Zhi-Wei

    2015-06-15

    A novel red-emitting phosphor Ba10F2(PO4)6:Eu(3+) is synthesized by a high-temperature solid-state reaction. X-ray powder diffraction (XRD) analysis confirms the phase formation of Ba10F2(PO4)6:Eu(3+) materials. The photoluminescence excitation (PLE) and emission (PL) spectra, the concentration dependence of the emission intensity, decay curves and Commission International de I'Eclairage (CIE) of the phosphors are investigated. It is observed that Ba10F2(PO4)6:Eu(3+) phosphors exhibit two dominating bands situated at 591 and 616 nm, originating from the (5)D0→(7)F1 and (5)D0→(7)F2 transition of the Eu(3+) ion, respectively. The decay time is also determined for various concentrations of Eu(3+) in Ba10F2(PO4)6:Eu(3+). Crystal lattice, PL spectra and decay time analysis indicate there exist two isolated Eu(3+) crystallography sites in Ba10F2(PO4)6. The calculated color coordinates lie in the red region. Therefore, Ba10F2(PO4)6:Eu(3+) phosphors may be good candidates for red components in near-UV (NUV) white LEDs. PMID:25775944

  18. Luminescent properties of blue emitting phosphor SrZn2(PO4)2:Eu2+ for white LEDs

    NASA Astrophysics Data System (ADS)

    Lu, Wei; Liu, Yu-fei; Wang, Ying; Wang, Zhi-jun; Pang, Li-bin

    2015-11-01

    Blue emitting phosphor SrZn2(PO4)2:Eu2+ is synthesized by a high temperature solid state method, and the luminescent properties are investigated. At the 330 nm radiation excitation, SrZn2(PO4)2:Eu2+ presents an emission band at 416 nm, which is assigned to the 4f65d1→4f7 transition of Eu2+ ion. The concentration quenching effect of Eu2+ in SrZn2(PO4)2 has been validated and proved to be a resonant type via a dipole-dipole interaction. The critical distance ( R c) of Eu2+ in SrZn2(PO4)2 is calculated to be 3.244 nm. The Commission International de I'Eclairage (CIE) chromaticity coordinates of SrZn2(PO4)2:Eu2+ locate at the blue region, such as (0.150, 0.072). The results indicate that the SrZn2(PO4)2:Eu2+ phosphor may have potential applications in white light emitting diodes (LEDs).

  19. Three-dimensional graphene/LiFePO{sub 4} nanostructures as cathode materials for flexible lithium-ion batteries

    SciTech Connect

    Ding, Y.H.; Ren, H.M.; Huang, Y.Y.; Chang, F.H.; Zhang, P.

    2013-10-15

    Graphical abstract: Graphene/LiFePO{sub 4} composites as a high-performance cathode material for flexible lithium-ion batteries have been prepared by using a co-precipitation method to synthesize graphene/LiFePO4 powders as precursors and then followed by a solvent evaporation process. - Highlights: • Flexible LiFePO{sub 4}/graphene films were prepared first time by a solvent evaporation process. • The flexible electrode exhibited a high discharge capacity without conductive additives. • Graphene network offers the electrode adequate strength to withstand repeated flexing. - Abstract: Three-dimensional graphene/LiFePO{sub 4} nanostructures for flexible lithium-ion batteries were successfully prepared by solvent evaporation method. Structural characteristics of flexible electrodes were investigated by X-ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). Electrochemical performance of graphene/LiFePO{sub 4} was examined by a variety of electrochemical testing techniques. The graphene/LiFePO{sub 4} nanostructures showed high electrochemical properties and significant flexibility. The composites with low graphene content exhibited a high capacity of 163.7 mAh g{sup −1} at 0.1 C and 114 mAh g{sup −1} at 5 C without further incorporation of conductive agents.

  20. 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.

  1. LiTi 2(PO 4) 3 with NASICON-type structure as lithium-storage materials

    NASA Astrophysics Data System (ADS)

    Wang, G. X.; Bradhurst, D. H.; Dou, S. X.; Liu, H. K.

    LiTi 2(PO 4) 3 with a Na + superionic conductor (NASICON)-type structure is prepared by a two-step solid-state reaction. X-ray diffraction (XRD) confirms that the LiTi 2(PO 4) 3 compound has a NASICON structure, i.e. rhombohedral (space group: R3 c). It is found that lithium can be electrochemically inserted into the LiTi 2(PO 4) 3 structure, with a maximum intake of 5.2 mol of lithium per mole of LiTi 2(PO 4) 3 compound, and that [PO 4] tetrahedra can participate in the redox reaction. This corresponds to a lithium-storage capacity of 360 mAh g -1. The kinetic parameters of lithium insertion in LiTi 2(PO 4) 3 NASICON are determined by means of ac impedance technique. The charge-transfer resistance ( RCT) and exchange current density ( i0) are invariable regardless of the state of lithium insertion. This is associated with the unique structure characteristics of the NASICON skeleton. By contrast, the diffusion coefficient, DLi of lithium varies with the state of lithium insertion. The value of DLi is in the range 1.4×10 -11 to 1.2×10 -9 m 2 s -1, which is much higher than for other intercalation materials.

  2. 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

  3. 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.

  4. Studies on the distribution of 210Po and 210Pb in the ecosystem of Point Calimere Coast (Palk Strait), India.

    PubMed

    Suriyanarayanan, S; Brahmanandhan, G M; Malathi, J; Ravi Kumar, S; Masilamani, V; Shahul Hameed, P; Selvasekarapandian, S

    2008-04-01

    A systematic study on the natural radionuclides such as 210Po and 210Pb in the environmental matrices of Point Calimere ecosystem has been undertaken to establish a baseline data on the radiation profile of Point Calimere environment. The environmental samples such as water, sediment and biota (seaweeds, crustaceans, molluscs and fish) have been subjected to analyses. It has been observed that the concentration of 210Po and 210Pb in the water samples of Point Calimere to be 0.5 mBq/l and 1.3 mBq/l, respectively. The soft tissues of the organisms accumulated higher 210Po content while shells and bones contained more 210Pb. The bivalve molluscs Meretrix casta have been identified to accumulate higher concentration of 210Po suggesting that they could serve as bio-indicator of radionuclides like 210Po in the Point Calimere ecosystem. The concentration factor of 210Po for the biotic components ranged from approximately 10(3) to 10(6) while for 210Pb it ranged from approximately 10(3) to 10(5). PMID:18035457

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. (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

  10. 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

  11. 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.

  12. 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

  13. Experimental and numerical study of phase transition of LiFePO 4 material in lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Siddique, Md Noor E. Alam

    Phase transition behavior of LiFePO4 material has been studied in this work. During electrochemical charge/discharge processes, LiFePO 4 transforms into FePO4 and this electrochemically driven phase transition of the two-phase system results in a potential plateau in a battery discharge curve. Besides, battery performance, especially under high rates, depends critically on this two-phase transition. However, this phase transition mechanism in the LiFePO4 crystal structure has yet not been understood in details. Developing better understanding is essential for designing high performing, safe and stable batteries. Currently available phase transition models for LiFePO4, such as the classical `core-shrinking model' and recently the `domino cascade model', have shed lights on the phase transition mechanism, however, with somewhat contradicting conclusions. The former predicted a continuous phase transition between LiFePO4 and FePO4 within an individual particle. In contrast, the latter, based on the fact of anisotropic diffusion of Li, provided a microscopically heterogeneous picture of phase transition: phase transition is abrupt, and de-lithiated and lithiated particles co-exist in a battery electrode. To achieve a better understanding of the two-phase transition phenomena, two specially designed sophisticated methods, i.e., in-situ Raman spectroscopy and in-situ X-ray Diffraction (XRD), have been developed in this work. The particle level phase transition of LiFePO4 was probed in the in-situ Raman study. Under slow-rate discharge/charge, it was found that the particles were either fully transformed or untransformed indicating that the phase transition in LiFePO4 material was not uniform at the particle level. Electronic conductivity and local electrode microstructure determined the preferred sequence of phase transition of the particles. This study also revealed that non-equilibrium phase transition occurred as a result of delayed phase transition. The in-situ XRD

  14. Distribution of (226)Ra-(210)Pb-(210)Po in marine biota and surface sediments of the Red Sea, Sudan.

    PubMed

    Sirelkhatim, D A; Sam, A K; Hassona, R K

    2008-12-01

    Activity concentration levels and ratios of (226)Ra, (210)Pb and (210)Po are presented in multicellular marine algae, molluscs, coral as well as in surface marine sediments collected from the shallower waters of the fringing reefs area extending towards north and south (Flamingo bay) of PortSudan harbour, Sudan. The analyses were performed adopting alpha-spectrometry, liquid scintillation and Cerenkov counting techniques. Surface sediments from this coastal region are poor in their radioactivity content in contrast to similar data reported from different coastal areas around the globe. There is surface enrichment of (210)Pb and (210)Po with respect to their progenitor (226)Ra as it is evident from the activity ratios of (210)Pb/(226)Ra (3.03+/-1.79) and (210)Po/(226)Ra (2.23+/-1.56). Among marine plants and animals investigated, the green algae species, Halimeda, and coral species, Favites, show substantial concentration of radium at 8.2Bq/kg and 21.9Bq/kg dry weight, respectively. Similarly, the highest concentration of (210)Po was met in Favites at 38.7Bq/kg followed by brown algae, Cystoseria sp., at 32.6Bq/kg. There is no variation seen among algal species for (210)Pb uptake, however, converse to radium and polonium, Favites (coral) was found to contain the minimum concentration of lead (3.88Bq/kg). In most species there is preferential accumulation of polonium over its parent radium as indicated by (210)Po:(226)Ra activity ratio with Cystoseria (brown algae) showing the highest value at 8.81. On the other hand, (210)Po:(210)Pb activity concentration ratio revealed that coral species Favites (9.97) and the brown algae Sargassum (1.85) have a greater tendency to accumulate (210)Po over (210)Pb, while in the rest of species; this ratio is less than unity. PMID:18774629

  15. Synthesis of a LiFePO4/C cathode material by using a high-energy nano mill

    NASA Astrophysics Data System (ADS)

    Islam, Mobinul; Yoon, Man-Soon; Ur, Soon-Chul

    2015-07-01

    Olivine lithium iron phosphate (LiFePO4) is a promising cathode material for Li-ion battery. A temperature around 700 - 800 ℃ is generally required to prepare LiFePO4 powder with good crystallinity. The LiFePO4 materials are synthesized via a solid-state method by using a highenergy nano mill (HENM). The conventional ball-milling process is also conducted for the same material for a comparative study. The effect of the precursor's mixing processes on the synthesis temperature of LiFePO4 is investigated in this study. The required reaction temperature of LiFePO4 is 432 ℃ for the HENM process and 480 ℃ for the ball-mill process as found from the differential scanning calorimetry (DSC) results. The HENM process improves the reaction activity and the homogeneity of the materials used throughout process and lowers the reaction temperature as compared with the conventional ball-mill process. The milled powders are characterized by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The sample synthesized by using the HENM process exhibits a discharge capacity of 136 mAhg -1 at 0.1 C rate. The results in this study indicate that the HENM process is a substantial and promising process for LiFePO4 cathode preparation owing to its short fabrication time and ability to improve the reaction condition. A HENM can be used to promote formation of LiFePO4 at lower temperatures.

  16. Why LiFePO4 is a safe battery electrode: Coulomb repulsion induced electron-state reshuffling upon lithiation.

    PubMed

    Liu, Xiaosong; Wang, Yung Jui; Barbiellini, Bernardo; Hafiz, Hasnain; Basak, Susmita; Liu, Jun; Richardson, Thomas; Shu, Guojiun; Chou, Fangcheng; Weng, Tsu-Chien; Nordlund, Dennis; Sokaras, Dimosthenis; Moritz, Brian; Devereaux, Thomas P; Qiao, Ruimin; Chuang, Yi-De; Bansil, Arun; Hussain, Zahid; Yang, Wanli

    2015-10-21

    LiFePO4 is a battery cathode material with high safety standards due to its unique electronic structure. We performed systematic experimental and theoretical studies based on soft X-ray emission, absorption, and hard X-ray Raman spectroscopy of LixFePO4 nanoparticles and single crystals. The results clearly show a non-rigid electron-state reconfiguration of both the occupied and unoccupied Fe-3d and O-2p states during the (de)lithiation process. We focus on the energy configurations of the occupied states of LiFePO4 and the unoccupied states of FePO4, which are the critical states where electrons are removed and injected during the charge and discharge process, respectively. In LiFePO4, the soft X-ray emission spectroscopy shows that, due to the Coulomb repulsion effect, the occupied Fe-3d states with the minority spin sit close to the Fermi level. In FePO4, the soft X-ray absorption and hard X-ray Raman spectroscopy show that the unoccupied Fe-3d states again sit close to the Fermi level. These critical 3d electron state configurations are consistent with the calculations based on modified Becke and Johnson potentials GGA+U (MBJGGA+U) framework, which improves the overall lineshape prediction compared with the conventionally used GGA+U method. The combined experimental and theoretical studies show that the non-rigid electron state reshuffling guarantees the stability of oxygen during the redox reaction throughout the charge and discharge process of LiFePO4 electrodes, leading to the intrinsic safe performance of the electrodes. PMID:26388021

  17. Time Scale of Gas Accumulation before the 2010 Eyjafjallajökull Eruption (Iceland) from 210Po Radioactive Excess

    NASA Astrophysics Data System (ADS)

    Sigmarsson, O.

    2015-12-01

    The 2010 mildly explosive eruption at Eyjafjallajökull, Iceland, produced mingled tephra of benmoreitic and trachytic composition whereas alkali basalt was emitted during preceding flank eruption. Tephra of the first explosive phase are composed of three glass types, alkaline rhyolite, mixed benmoreite, and basalt. The early formed benmoreitic tephra (erupted on 15 and 17 April 2010) had large 210Po in excess of 210Pb [(210Po/210Pb)0= 1.88)] at the time of eruption, and possibly a small 210Pb excess over its parent 226Ra. In contrast, the preceding flank eruption produced basalt with (210Po)0 = 0, upon eruption, and the final trachyte (end of May 2010) had lost most of its 210Po during open-system degassing. The 210Po excess in the first erupted benmoreites is interpreted to result from 210Po degassing of basaltic magma and the accumulation of 210Po-enriched gas, either in the upper part of the basaltic intrusion, below the rhyolite-basalt interface, on in the pre-existing residual rhyolitic magma chamber. A model of radon and polonium accumulation in the rhyolitic reservoir, allows calculating the ratio of mass of basalt magma degassing over mass of magma accumulating excess gas. This ratio decreased from 20 to 15 over 2 days, implying zoned magma reservoir, with the uppermost and gas-richest part erupted first. The duration of pre-eruptive gas accumulation in this model is approximately one year. This corresponds closely to the initiation of a seismic swarm beneath Eyjafjallajökull, early June 2009, which was the first pre-eruptive signal detected. The coincidence between initiation of gas accumulation at relatively shallow depth and deeper seismicity strongly suggests that the excess gas phase originated from a basalt magma batch intruded at depth, and that this gas phase reached the surface approximately a year later.

  18. Polymorphism, phase transitions, and thermal expansion of K3Lu(PO4)2

    SciTech Connect

    Farmer, James Matthew; Boatner, Lynn A; Chakoumakos, Bryan C; Rawn, Claudia J.; Mandrus, D.; Bryan, Jeff C.

    2014-01-01

    Alkali rare-earth double phosphates have been studied for use as long-wavelength scintillators for -ray detection using Si photodiodes. Single-crystal and powder x-ray diffraction (XRD) and powder neutron diffraction have been used to study the structure as a function of temperature. K3Lu(PO4)2 crystallizes with a hexagonal unit cell at room temperature, space group P 3. The Lu ion is six-coordinated to the oxygen atoms of the phosphate groups. Two lower-temperature phases were characterized using single-crystal XRD and powder neutron diffraction. The first transition occurs at 230 K with a transformation to a monoclinic P21/m space group symmetry, and the Lu retains six coordination. The second phase transition occurs at 130 K, with a large change in the cell volume, keeping the same P21/m space group symmetry; however, one of the phosphate groups rotates to increase the coordination of the Lu ion to seven. This is an unusual example of an isosymmetric phase transition with a coordination change, driven by temperature. High-temperature powder neutron diffraction and high-temperature powder XRD have been used to study the thermal expansion of K3Lu(PO4)2 and indicate a large thermal expansion anisotropy. The crystallographic axes with largest changes account for the structural collapse, which rotates the phosphate group to increase the Lu coordination. The lowest temperature form of K3Lu(PO4)2 is the same as the room temperature form for all the lighter RE compounds of the same type, which is not surprising, given the lighter (larger) RE ions would prefer a higher coordination number.

  19. Aquifer recharge from infiltration basins in a highly urbanized area: the river Po Plain (Italy)

    NASA Astrophysics Data System (ADS)

    Masetti, M.; Nghiem, S. V.; Sorichetta, A.; Stevenazzi, S.; Santi, E. S.; Pettinato, S.; Bonfanti, M.; Pedretti, D.

    2015-12-01

    Due to the extensive urbanization in the Po Plain in northern Italy, rivers need to be managed to alleviate flooding problems while maintaining an appropriate aquifer recharge under an increasing percentage of impermeable surfaces. During the PO PLain Experiment field campaign in July 2015 (POPLEX 2015), both active and under-construction infiltration basins have been surveyed and analyzed to identify appropriate satellite observations that can be integrated to ground based monitoring techniques. A key strategy is to have continuous data time series on water presence and level within the basin, for which ground based monitoring can be costly and difficult to be obtained consistently.One of the major and old infiltration basin in the central Po Plain has been considered as pilot area. The basin is active from 2003 with ground based monitoring available since 2009 and supporting the development of a calibrated unsaturated-saturated two-dimensional numerical model simulating the infiltration dynamics through the basin.A procedure to use satellite data to detect surface water change is under development based on satellite radar backscatter data with an appropriate incidence angle and polarization combination. An advantage of satellite radar is that it can observe surface water regardless of cloud cover, which can be persistent during rainy seasons. Then, the surface water change is correlated to the reservoir water stage to determine water storage in the basin together with integrated ground data and to give quantitative estimates of variations in the local water cycle.We evaluated the evolution of the infiltration rate, to obtain useful insights about the general recharge behavior of basins that can be used for informed design and maintenance. Results clearly show when the basin becomes progressively clogged by biofilms that can reduce the infiltration capacity of the basin by as much as 50 times compared to when it properly works under clean conditions.

  20. Denoising, deconvolving, and decomposing photon observations. Derivation of the D3PO algorithm

    NASA Astrophysics Data System (ADS)

    Selig, Marco; Enßlin, Torsten A.

    2015-02-01

    The analysis of astronomical images is a non-trivial task. The D3PO algorithm addresses the inference problem of denoising, deconvolving, and decomposing photon observations. Its primary goal is the simultaneous but individual reconstruction of the diffuse and point-like photon flux given a single photon count image, where the fluxes are superimposed. In order to discriminate between these morphologically different signal components, a probabilistic algorithm is derived in the language of information field theory based on a hierarchical Bayesian parameter model. The signal inference exploits prior information on the spatial correlation structure of the diffuse component and the brightness distribution of the spatially uncorrelated point-like sources. A maximum a posteriori solution and a solution minimizing the Gibbs free energy of the inference problem using variational Bayesian methods are discussed. Since the derivation of the solution is not dependent on the underlying position space, the implementation of the D3PO algorithm uses the nifty package to ensure applicability to various spatial grids and at any resolution. The fidelity of the algorithm is validated by the analysis of simulated data, including a realistic high energy photon count image showing a 32 × 32 arcmin2 observation with a spatial resolution of 0.1 arcmin. In all tests the D3PO algorithm successfully denoised, deconvolved, and decomposed the data into a diffuse and a point-like signal estimate for the respective photon flux components. A copy of the code is available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/574/A74

  1. Nanosized helical magnetic domains in strongly frustrated Fe3PO4O3

    NASA Astrophysics Data System (ADS)

    Ross, K. A.; Bordelon, M. M.; Terho, G.; Neilson, J. R.

    2015-10-01

    Fe3PO4O3 forms a noncentrosymmetric lattice structure (space group R 3 m ) comprising triangular motifs of Fe3 + coupled by strong antiferromagnetic interactions (| ΘC W|>900 K). Neutron diffraction from polycrystalline samples shows that strong frustration eventually gives way to an ordered helical incommensurate structure below TN = 163 K, with the helical axis in the hexagonal a b plane and a modulation length to ˜86 Å. The magnetic structure consists of an unusual needlelike correlation volume that extends past 900 Å along the hexagonal c axis but is limited to ˜70 Å in the a b plane, despite the three-dimensional nature of the magnetic sublattice topology. The small in-plane correlation length, which persists to at least T =TN/40 , indicates a robust blocking of long-range order of the helical magnetic structure, and therefore stable domain walls, or other defect spin textures, must be abundant in Fe3PO4O3 . Temperature-dependent neutron powder diffraction reveals small negative thermal expansion below TN. No change in lattice symmetry is observed on cooling through TN, as revealed by high-resolution synchrotron x-ray diffraction. The previously reported reduced moment of the Fe3 + ions (S =5 /2 ), μ ˜4.2 μB , is confirmed here through magnetization studies of a magnetically diluted solid solution series of compounds, Fe(3 -x )GaxPO4O3 , and is consistent with the refined magnetic moment from neutron diffraction 4.14(2) μB. We attribute the reduced moment to a modified spin density distribution arising from ligand charge transfer in this insulating oxide.

  2. Facts and perceptions on the flood-risk evolution along the Po River

    NASA Astrophysics Data System (ADS)

    Domeneghetti, Alessio; Carisi, Francesca; Castellarin, Attilio

    2014-05-01

    Has the flood risk increased in the Po river basin during the last half century? The increasing frequency with which floods damages are recorded, or reported by media, strengthen the common perception that the flood risk is dramatically increasing in Europe and other areas of the world, due to a combination of different causes, among which climate change is often described as the major factor. However, there is a growing awareness of how anthropogenic pressures, such as uncontrolled urban and industrial expansion on flood-prone areas, may strongly impact the evolution of flood-risk in a given area, increasing potential flood damages and losses. Starting from these considerations, our study aims at shedding some light on the impact and relative importance of different factors controlling the flood risk. Focusing in particular on the middle-lower portion of the River Po, we analyse the evolution of flood hazard in the last half century referring to long streamflow series for different gauging stations located along the study reach (~450 km), while the modification of anthropogenic pressure is evaluated by referring to land-use and demographic dynamics observed from 1950s. Our study proposes simplified flood-vulnerability indices to be used for large scale flood-risk assessments and, on the basis of these indices, (1) we assess the importance of the different elements contributing to the definition of flood risk and (2) represent the evolution of flood risk in time along the middle and lower portion of the River Po. The results of the study represent an important piece of information that can be particularly useful to decision-makers in the definition of large scale flood-risk mitigation strategies and development plans for the study area.

  3. Effects of digestion, chemical separation, and deposition on Po-210 quantitative analysis

    SciTech Connect

    Seiner, Brienne N.; Morley, Shannon M.; Beacham, Tere A.; Haney, Morgan M.; Gregory, Stephanie J.; Metz, Lori A.

    2014-10-01

    Polonium-210 is a radioactive isotope often used to study sedimentation processes, food chains, aerosol behavior, and atmospheric circulations related to environmental sciences. Materials for the analysis of Po-210 range from tobacco leaves or cotton fibers, to soils and sediments. The purpose of this work was to determine polonium losses from a variety of sample types (soil, cotton fiber, and air filter) due to digestion technique, chemical separation, and deposition method for alpha energy analysis. Results demonstrated that yields from a perchloric acid wet-ash were similar to that from a microwave digestion. Both were greater than the dry-ash procedure. The polonium yield from the perchloric acid wet ash was 87 ± 5%, the microwave digestion had a yield of 100 ± 7%, and the dry ash had a yield of 38 ± 5%. The chemical separation of polonium by an anion exchange resin was used only on the soil samples due to the complex nature of this sample. The yield of Po-209 tracer after chemical separation and deposition for alpha analysis was 83 ± 7% for the soil samples. Spontaneous deposition yields for the cotton and air filters were 87 ± 4% and 92 ± 6%, respectively. Based on the overall process yields for each sample type the amount of Po-210 was quantified using alpha energy analysis. The soil contained 0.18 ± 0.08 Bq/g, the cotton swipe contained 0.7 mBq/g, and the air filter contained 0.04 ± 0.02 mBq/g. High and robust yields of polonium are possible using a suitable digestion, separation, and deposition method.

  4. Alkali-calcic and alkaline post-orogenic (PO) granite magmatism: petrologic constraints and geodynamic settings

    NASA Astrophysics Data System (ADS)

    Bonin, Bernard; Azzouni-Sekkal, Abla; Bussy, François; Ferrag, Sandrine

    1998-12-01

    The end of an orogenic Wilson cycle corresponds to amalgamation of terranes into a Pangaea and is marked by widespread magmatism dominated by granitoids. The post-collision event starts with magmatic processes still influenced by subducted crustal materials. The dominantly calc-alkaline suites show a shift from normal to high-K to very high-K associations. Source regions are composed of depleted and later enriched orogenic subcontinental lithospheric mantle, affected by dehydration melting and generating more and more K- and LILE-rich magmas. In the vicinity of intra-crustal magma chambers, anatexis by incongruent melting of hydrous minerals may generate peraluminous granitoids bearing mafic enclaves. The post-collision event ends with emplacement of bimodal post-orogenic (PO) suites along transcurrent fault zones. Two suites are defined, (i) the alkali-calcic monzonite-monzogranite-syenogranite-alkali feldspar granite association characterised by [biotite+plagioclase] fractionation and moderate [LILE+HFSE] enrichments and (ii) the alkaline monzonite-syenite-alkali feldspar granite association characterised by [amphibole+alkali feldspar] fractionation and displaying two evolutionary trends, one peralkaline with sodic mafic mineralogy and higher enrichments in HFSE than in LILE, and the other aluminous biotite-bearing marked by HFSE depletion relative to LILE due to accessory mineral precipitation. Alkali-calcic and alkaline suites differ essentially in the amounts of water present within intra-crustal magma chambers, promoting crystallisation of various mineral assemblages. The ultimate enriched and not depleted mantle source is identical for the two PO suites. The more primitive LILE and HFSE-rich source rapidly replaces the older orogenic mantle source during lithosphere delamination and becomes progressively the thermal boundary layer of the new lithosphere. Present rock compositions are a mixture of major mantle contribution and various crustal components

  5. 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. PMID:25068956

  6. Stability, structure refinement, and magnetic properties of β-Fe 2(PO 4)O

    NASA Astrophysics Data System (ADS)

    Ijjaali, M.; Malaman, B.; Gleitzer, C.; Warner, J. K.; Hriljac, J. A.; Cheetham, A. K.

    1990-06-01

    We previously reported the existence and properties of a low-temperature modification of metastable β-Fe 2(PO 4)O. Its structure was proposed by analogy with NiCr(PO 4)O, but the magnetic measurements were hampered by traces of Fe 3O 4. We have now obtained a purer sample and a single crystal, allowing precise structure refinement, detailed magnetic characterization, and an investigation of the temperature stability range. The single crystal X-ray study confirms the structure as previously proposed: tetragonal ( Z = 4), SG {I4 1}/{amd}, with a single iron site in face-sharing octahedra, and isolated PO 4 tetrahedra; the reliability factor is R = 0.0345 ( Rw = 0.0363). The magnetic susceptibility has been measured from 4 to 850 K. The magnetization at zero applied field is around 0.01 emu/g at 300 and 88 K, and 0.04 emu/g at 3.5 K. The χ = f( T) curve displays several unusual features: above TN (408 K) the Curie constant continuously decreases as a consequence of short-range magnetic order; below 100 K the susceptibility displays a small second maximum at 12 K. The magnetic structure has been investigated by low temperature powder neutron diffraction methods. At 17 K the Fe (II/III) spins are ordered ferromagnetically within the chains of face-sharing FeO 6 octahedra, with the spin direction along (001). The chains are ordered antiferromagnetically with respect to each other. The phase stability has been investigated by high temperature X-ray diffraction. The nonreversible β → α transition takes place at ˜800°C and is completed at ˜840°C; however, the β phase stability is slightly lower in the presence of FeCl 2 traces or under high pressure.

  7. Fermi Surface of Superconducting LaFePO Determined by Quantum Oscillations

    SciTech Connect

    Coldea, A.I.; Fletcher, J.D.; Carrington, A.; Analytis, J.G.; Bangura, A.F.; Chu, J.-H.; Erickson, A.S.; Fisher, I.R.; Hussey, N.E.; McDonald, R.D.; /Los Alamos

    2010-01-11

    We report extensive measurements of quantum oscillations in the normal state of the Fe-based superconductor LaFePO, (T{sub c} {approx} 6 K) using low temperature torque magnetometry and transport in high static magnetic fields (45 T). We find that the Fermi surface is in broad agreement with the band-structure calculations with the quasiparticle mass enhanced by a factor {approx}2. The quasi-two dimensional Fermi surface consist of nearly-nested electron and hole pockets, suggesting proximity to a spin/charge density wave instability.

  8. Long-term trend and variability of atmospheric PM10 concentration in the Po Valley

    NASA Astrophysics Data System (ADS)

    Bigi, A.; Ghermandi, G.

    2014-05-01

    The limits to atmospheric pollutant concentration set by the European Commission provide a challenging target for the municipalities in the Po Valley, because of the characteristic climatic conditions and high population density of this region. In order to assess climatology and trends in the concentration of atmospheric particles in the Po Valley, a data set of PM10 data from 41 sites across the Po Valley have been analysed, including both traffic and background sites (either urban, suburban or rural). Of these 41 sites, 18 with 10 yr or longer record have been analysed for long-term trend in deseasonalized monthly means, in annual quantiles and in monthly frequency distribution. A widespread significant decreasing trend has been observed at most sites, up to a few percent per year, by a generalized least squares and Theil-Sen method. All 41 sites have been tested for significant weekly periodicity by Kruskal-Wallis test for mean anomalies and by Wilcoxon test for weekend effect magnitude. A significant weekly periodicity has been observed for most PM10 series, particularly in summer and ascribed mainly to anthropic particulate emissions. A cluster analysis has been applied in order to highlight stations sharing similar pollution conditions over the reference period. Five clusters have been found, two encompassing the metropolitan areas of Turin and Milan and their respective nearby sites and the other three clusters gathering northeast, northwest and central Po Valley sites respectively. Finally, the observed trends in atmospheric PM10 have been compared to trends in provincial emissions of particulates and PM precursors, and analysed along with data on vehicular fleet age, composition and fuel sales. A significant basin-wide drop in emissions occurred for gaseous pollutants, contrarily to emissions of PM10 and PM2.5, whose drop was low and restricted to a few provinces. It is not clear whether the decrease for only gaseous emissions is sufficient to explain the

  9. A first principle study of the pressure dependent elastic properties of monazite LaPO4

    NASA Astrophysics Data System (ADS)

    Ali, Kawsar; Arya, A.; Ghosh, P. S.; Dey, G. K.

    2016-05-01

    DFT based ab-initio simulations have been performed to study the effect of pressure on the elastic properties of monazite LaPO4 which is a promising host material for immobilization of high level nuclear waste. The phase is found to be stable up to 30 GPa. The calculated polycrystalline bulk, shear and Young moduli show an increasing trend as a function of pressure. The ductility and anisotropy in shear modulus of the material have been found to increase with pressure; whilethe bulk modulus anisotropy decreases with pressure.

  10. A high performance hybrid battery based on aluminum anode and LiFePO4 cathode

    DOE PAGESBeta

    Sun, Xiao-Guang; Bi, Zhonghe; Liu, Hansan; Bridges, Craig A.; Paranthaman, Mariappan Parans; Dai, Sheng; Brown, Gilbert M.

    2015-12-07

    A unique battery hybrid utilizes an aluminum anode, a LiFePO4 cathode and an acidic ionic liquid electrolyte based on 1-ethyl-3-methylimidazolium chloride (EMImCl) and aluminum trichloride (AlCl 3) (EMImCl-AlCl 3, 1-1.1 in molar ratio) with or without LiAlCl4 is proposed. This hybrid ion battery delivers an initial high capacity of 160 mAh g-1 at a current rate of C/5. It also shows good rate capability and cycling performance.

  11. TEM Study of Fracturing in Spherical and Plate-like LiFePO4Particles

    SciTech Connect

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

    2007-12-20

    An investigation of fracturing in LiFePO{sub 4} particles as a function of the particle morphology and history is presented. Two types of samples, one subjected to electrochemical cycling and another to chemical delithiation are compared. We observe the formation of micro fractures parallel to low indexed lattice planes in both samples. The fracture surfaces are predominantly parallel to (100) planes in the chemically delithiated powder and (100) and (010) planes in the electrochemically cycled powder. A consideration of the threshold stresses for dislocation glide shows that particle geometry plays an important role in the observed behavior.

  12. Asymmetry of fission fragment mass distribution for Po and Ir isotopes

    NASA Astrophysics Data System (ADS)

    Andreev, A. V.; Adamian, G. G.; Antonenko, N. V.

    2016-03-01

    Using the improved scission-point model, the mass distributions are calculated for induced fission of several Po and Ir isotopes. The calculated mass distributions and mean total kinetic energies of fission fragments are compared with the existing experimental data. The revealed coexistence of both symmetric and asymmetric modes in the β -delayed fission of At,196194 is in agreement with the experimental observations. The change of the shape of mass distribution with increasing A of fissioning AIr nucleus from asymmetric for 185Ir to symmetric for 193Ir is found.

  13. Astronomie, écologie et poésie par Hubert Reeves

    ScienceCinema

    None

    2011-10-06

    Hubert ReevesL'astrophysicien donne une conférence puis s'entretient avec l'écrivain François Bon autour de :"Astronomie, écologie et poésie"Pour plus d'informations : http://outreach.web.cern.ch/outreach/FR/evenements/conferences.htmlNombre de places limité. Réservation obligatoire à la Réception du CERN : +41 22 767 76 76  Soirée diffusée en direct sur le Web : http://webcast.cern.ch/      

  14. Solid-state, rechargeable Li/LiFePO 4 polymer battery for electric vehicle application

    NASA Astrophysics Data System (ADS)

    Damen, L.; Hassoun, J.; Mastragostino, M.; Scrosati, B.

    A solid-state polymer lithium metal battery having a LiFePO 4/C composite cathode and a poly(ethylene oxide) PEO-based solid polymer electrolyte was assembled and characterized in terms of specific energy and power according to the protocol for electric vehicle (EV) application set by the USABC-DOE. The results of these tests show that this polymer battery surpasses the goals stated by USABC-DOE and, hence, may be suitable for application in the evolving EV market.

  15. A high performance hybrid battery based on aluminum anode and LiFePO4 cathode.

    PubMed

    Sun, Xiao-Guang; Bi, Zhonghe; Liu, Hansan; Fang, Youxing; Bridges, Craig A; Paranthaman, M Parans; Dai, Sheng; Brown, Gilbert M

    2016-01-28

    A novel hybrid battery utilizing an aluminum anode, a LiFePO4 cathode and an acidic ionic liquid electrolyte based on 1-ethyl-3-methylimidazolium chloride (EMImCl) and aluminum trichloride (AlCl3) (EMImCl-AlCl3, 1-1.1 in molar ratio) with or without LiAlCl4 is proposed. The hybrid ion battery delivers an initial high capacity of 160 mA h g(-1) at a current rate of C/5. It also shows good rate capability and cycling performance. PMID:26666453

  16. Shock wave induced phase transition in α -FePO 4

    NASA Astrophysics Data System (ADS)

    Joshi, K. D.; Suresh, N.; Jyoti, G.; Kulshreshtha, S. K.; Gupta, S. C.; Sikka, S. K.

    Shock wave induced response of the berlinite form of FePO 4 has been investigated up to 8.5 GPa. The X-ray diffraction measurements on the shock recovered samples reveal transition to the mixture of an amorphous phase and an orthorhombic phase around 5 GPa. The proportion of the amorphous material in the recovered sample is found to decrease at higher pressure. The results are interpreted in terms of a three-level free energy diagram for the crystal to amorphous transitions.

  17. Get Involved in Education and Public Outreach! The Science Mission Directorate Science E/PO Forums Are Here to Help

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    NASA's Science Mission Directorate (SMD) Education and Public Outreach (E/PO) Forums help to engage, extend, support, and coordinate the efforts of the community of E/PO professionals and scientists involved in Earth and space science education activities. This work is undertaken to maximize the effectiveness and efficiency of the overall national NASA science education and outreach effort made up of individual efforts run by these education professionals. This includes facilitating scientist engagement in education and outreach. The Forums have been developing toolkits and pathways to support planetary, Earth, astrophysics, and heliophysics scientists who are - or who are interested in becoming - involved in E/PO. These tools include: 1) Pathways to learn about SMD and E/PO community announcements and opportunities, share news about E/PO programs, let the E/PO community know you are interested in becoming involved, and discover education programs needing scientist input and/or support. These pathways include weekly e-news, the SMD E/PO online community workspace, monthly community calls, conferences and meetings of opportunity. 2) Portals to help you find out what education resources already exist, obtain resources to share with students of all levels - from K-12 to graduate students, - and disseminate your materials. These include E/PO samplers and toolkits (sampling of resources selected for scientists who work with students, teachers, and the public), the one-stop shop of reviewed resources from the NASA Earth and space science education portfolio NASAWavelength.org, and the online clearinghouse of Earth and space science higher education materials EarthSpace (http://www.lpi.usra.edu/earthspace). 3) Connections to education specialists who can help you design and implement meaningful E/PO programs - small to large. Education specialists can help you understand what research says about how people learn and effective practices for achieving your goals, place your

  18. Synthesis and characterization of Bi{sub 1−x}La{sub x}PO{sub 4} nano-rods

    SciTech Connect

    Singh, Sarabjot; Khan, Sheeba; Patel, D. K. Sudarsan, V.

    2014-04-24

    Monoclinic form of BiPO{sub 4} phase has been prepared based on the reaction of Bi{sup 3+} and PO{sub 4}{sup 3−} ions in ethylene glycol medium at 185°C. Monoclinic BiPO{sub 4} forms random solid solutions with lanthanide phosphates having monoclinic structure as confirmed by XRD and {sup 31}P solid state nuclear magnetic resonance studies.

  19. Improving governance action by an advanced water modelling system applied to the Po river basin in Italy

    NASA Astrophysics Data System (ADS)

    Alessandrini, Cinzia; Del Longo, Mauro; Pecora, Silvano; Puma, Francesco; Vezzani, Claudia

    2013-04-01

    In spite of the historical abundance of water due to rains and to huge storage capacity provided by alpine lakes, Po river basin, the most important Italian water district experienced in the past ten years five drought/water scarcity events respectively in 2003, 2006, 2007 and 2012 summers and in the 2011-2012 winter season. The basic approach to these crises was the observation and the post-event evaluation; from 2007 an advanced numerical modelling system, called Drought Early Warning System for the Po River (DEWS-Po) was developed, providing advanced tools to simulate the hydrological and anthropic processes that affect river flows and allowing to follow events with real-time evaluations. In early 2012 the same system enabled also forecasts. Dews-Po system gives a real-time representation of water distribution across the basin, characterized by high anthropogenic pressure, optimizing with specific tools water allocation in competing situations. The system represents an innovative approach in drought forecast and in water resource management in the Po basin, giving deterministic and probabilistic meteorological forecasts as input to a chain for numerical distributed modelling of hydrological and hydraulic simulations. The system architecture is designed to receive in input hydro-meteorological actually observed and forecasted variables: deterministic meteorological forecasts with a fifteen days lead time, withdrawals data for different uses, natural an artificial reservoirs storage and release data. The model details are very sharp, simulating also the interaction between Adriatic sea and Po river in the delta area in terms of salt intrusion forecasting. Calculation of return period through run-method and of drought stochastic-indicators are enabled to assess the characteristics of the on-going and forecasted event. An Inter-institutional Technical Board is constituted within the Po River Basin Authority since 2008 and meets regularly during water crises to act

  20. Luminescence properties of phosphate phosphor Ba{sub 3}Y(PO{sub 4}){sub 3}:Sm{sup 3+}

    SciTech Connect

    Yang, Fu; Liu, Yufeng; Tian, Xiaodong; Dong, Guoyi; Yu, Quanmao

    2015-05-15

    A series of reddish orange-emitting phosphate phosphors Ba{sub 3}Y{sub 1−x}(PO{sub 4}){sub 3}:xSm{sup 3+}(0.01≤x≤0.20) were synthesized by solid-state reaction. X-ray diffraction and photoluminescence spectra were utilized to characterize the structure and luminescence properties of as-synthesized phosphors. The optimized phosphors Ba{sub 3}Y{sub 0.95}(PO{sub 4}){sub 3}:0.05Sm{sup 3+} present several excitation bands from 300 to 500 nm, and exhibit intense reddish orange-emitting properties. The energy transfer type between Sm{sup 3+} ions was confirmed as d–d interaction by using Van Uitert model. The chromatic properties of the typical sample Ba{sub 3}Y(PO{sub 4}){sub 3}:0.05Sm{sup 3+} phosphor have been found to have chromaticity coordinates of (0.583, 0.405), which are located in reddish orange region under the excitation of 401 nm. These results indicated that Ba{sub 3}Y(PO{sub 4}){sub 3}:Sm{sup 3+} phosphors have potential applications in the field of lighting and display due to their effective excitation in the near-ultraviolet range. - Graphical abstract: The color coordinates for 5 mol% Sm{sup 3+} doped Ba{sub 3}Y(PO{sub 4}){sub 3} phosphor were calculated to be (0.583, 0.405), which are located in reddish orange region under the excitation of 401 nm. The peaks of Ba{sub 3}Y{sub 0.95}(PO{sub 4}){sub 3}:0.05Sm{sup 3+} phosphor with the highest emission intensity at 600 nm are broader than those of Y{sub 2}O{sub 3}:Eu{sup 3+} and Y{sub 2}O{sub 2}S:Eu{sup 3+} phosphors. All these characteristics suggest that Ba{sub 3}Y(PO{sub 4}){sub 3}:Sm{sup 3+} phosphors are suitable for near-UV (370–410 nm) excitation and can be applicable to near UV-based WLEDs. ▪ - Highlights: • Different concentration Sm{sup 3+}-doped Ba{sub 3}Y(PO{sub 4}){sub 3} phosphors were fabricated by solid state method. • The optimized phosphors present the several excitation bands from 300 to 500 nm. • The Ba{sub 3}Y(PO{sub 4}){sub 3}:Sm{sup 3+} shows bright reddish orange