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Sample records for group v elements

  1. Group-V elemental monolayers: the case of antimonene

    E-print Network

    Wang, Gaoxue; Karna, Shashi P

    2015-01-01

    Group-V elemental monolayers including phosphorene are emerging as promising 2D materials with semiconducting electronic properties. Here, we present the results of first principles calculations on stability, mechanical and electronic properties of 2D antimony, antimonene. Our calculations show that {\\alpha} and \\b{eta} allotropes of antimonene are stable and semiconducting. The {\\alpha}-Sb has a distorted atomic structure with two atomic sub-layers and \\b{eta}-Sb has a buckled hexagonal lattice. The calculated Raman spectra and STM images have distinct features identifying in-plane and out-of-plane vibrating modes in both allotropes. The \\b{eta}-Sb has nearly isotropic mechanical properties while {\\alpha}-Sb shows strongly anisotropic characteristics. An indirect-direct band gap transition is expected with moderate tensile strains applied to antimonene monolayers. Since the mechanical exfoliation (scotch tape) approach will be difficult to fabricate antimonene due to large binding energy of bilayers, the sta...

  2. Influence of the group V element on the chemical potential and crystal structure of Au-catalyzed III-V nanowires

    SciTech Connect

    Dubrovskii, V. G.

    2014-02-03

    We present a kinetic growth model having a particular emphasis on the influence of the group V element on the preferred crystal structure of Au-catalyzed III-V nanowires. The model circumvents the uncertainty in the group V contribution into the overall liquid chemical potential. We show why the nanowire elongation rate is limited by the group III transport, while the crystal structure depends on the effective group V to III imbalance. Within the model, we are able to explain some important structural trends in Au-catalyzed III-V nanowires. In particular, we show that high group V flux always favors wurtzite structure in molecular-beam epitaxy. This tendency could be inverted in vapor deposition techniques due to suppression of the group III diffusion at high group V flux.

  3. Theoretical and Materials Chemistry of Some Group III and V Elements

    NASA Astrophysics Data System (ADS)

    Glass, John Arthur, Jr.

    The theoretical and material aspects of some group III and V compounds have been investigated. Phosphaborane clusters were investigated by modified neglect of differential overlap semi-empirical molecular orbital calculations (MNDO -SCF) to better understand important structural, electronic, and thermodynamic properties of these experimentally difficult species. The structural, thermodynamic and electronic properties of 111 phosphapentaborane cluster compounds have been calculated via MNDO-SCF. The geometry-optimized, minimum energy structures for all of the known and structurally characterized phosphaborane systems have been calculated. In each case, exceptionally good agreement was observed between the experimentally determined and the calculated structural parameters. Calculations for five classes of phosphapentaborane clusters have been completed and have been related to experimentally proposed structural types. Predictions concerning structural and chemical reactivities for unknown and known phosphapentaborane compounds have been made based on these MO calculations. Production of important thin film materials was discussed relative to chemical vapor deposition (CVD). Advantages of CVD over older thermodynamic deposition techniques were described. The CVD process has been briefly reviewed through seven primary steps. The importance of new source materials which meet stringent industrial requirements have been detailed relative to environmental, occupational safety, and contaminations considerations. Thin films of pure aluminum, aluminum boride and aluminum oxide have been prepared from the chemical vapor deposition (CVD) of rm Al(BH_4)_3, and rm AlH_2(BH_4) cdot N(CH_3)_3, on both single crystals and thermally sensitive substrates. Films were characterized by EDX, AES, SEM, XRD, and resistivity measurements and ranged in thickness from 500 A to 2 mu m. Each type of film was shown by AES to be compositionally uniform in the bulk sample with only very shallow surface contaminations of oxygen and carbon. Both source compounds were, in general, relatively thermally stable, volatile, air-sensitive liquids, thus providing nearly ideal precursor properties for chemical vapor deposition. Organophosphorus sources for the chemical vapor deposition (CVD) of indium phosphide have been examined with MNDO-SCF theoretical calculations in order to predict important depositional parameters such as decomposition temperature and temperature selectivities. Decomposition temperatures and temperature selectivities for the three known organophosphorus sources, t-butyl phosphine (TBP), i-butyl phosphine (IBP) and bisphosphinoethane (BPE), have been shown to match MNDO's predicted values, indicating that MNDO can be used as a first test for the suitability of organophosphorus compounds. Optimized depositional parameters for TBP, IBP and BPE were presented. Alternative phosphorus sources with enhanced depositional properties have been identified and analyzed in terms of decomposition temperature and optimized deposition conditions. Cyclohexyl phosphine (PCH) has been used in conjunction with trimethyl indium (TMI) to deposit polycrystalline indium phosphide with no carbon incorporation. Attempted indium phosphide depositions using dichloro-t-butyl phosphine (DCTBP) and TMI yielded both an etching of the InP(100) surface (73.4 A/sec) and polycrystalline rm Cu_3P. .

  4. Finite element analysis of stress concentration in Class V restorations of four groups of restorative materials in mandibular premolar

    PubMed Central

    N, Shubhashini; N, Meena; Shetty, Ashish; Kumari, Anitha; DN, Naveen

    2008-01-01

    Aim: To study the concentration of stress in class V restoration of four different restorative materials subjected to occlusal load of 100N, 150N, 200N, 250N and to analyse the obtained data with the listed properties of the restorative material. Materials and Methods: Using FEM analysis the stresses generated in a class V lesion in a mandibular premolar was studied. Results: Within the framework of the aforementioned views, and from the results of the study it can be concluded that microfilled composite is the most suitable restorative material followed by flowable composite, glass ionomer cement and resin modified glass ionomer cement. Conclusion: Restoration of Class V lesions with materials of higher modulus of elasticity will enable better stress distribution. PMID:20142899

  5. Systems of elements preserving measure on varieties of groups

    SciTech Connect

    Timoshenko, E I

    2013-12-31

    It is proved that for any l, 1?l?r, a system of elements (v{sub 1},…,v{sub l}) of a free metabelian group S of rank r?2 is primitive if and only if it preserves measure on the variety of metabelian groups A{sup 2}. From this we obtain the result that a system of elements (v{sub 1},…,v{sub l}) is primitive in the group S if and only if it is primitive in its profinite completion S-hat . Furthermore, it is proved that there exist a variety M and a nonprimitive element v?F{sub r}(M) such that v preserves measure on M. Bibliography: 13 titles.

  6. Elements of Group Theory / Lie Groups Christian Herenz

    E-print Network

    Subgroup ( Simple-/Semisimple Group) Lie-Groups General Remarks Representations Lie-Algebras Bonus: PoincarElements of Group Theory / Lie Groups Christian Herenz Humboldt-Universit¨at zu Berlin - Institut f language of symmetries: group theory. Of special interest in elementary particle physics: Lie-Groups Some

  7. Experimental constraints on the partitioning of rhenium and some platinum-group elements between

    E-print Network

    Rudnick, Roberta L.

    Experimental constraints on the partitioning of rhenium and some platinum-group elements between in controlling the behavior of rhenium and the platinum group elements (PGEs) during basalt petrogenesis.V. All rights reserved. Keywords: trace element partitioning; platinum group elements; olivine

  8. Substantial enhancement in intrinsic coercivity on M-type strontium hexaferrite through the increase in magneto-crystalline anisotropy by co-doping of group-V and alkali elements

    SciTech Connect

    Ahn, Kyunghan Ryu, Byungki; Korolev, Dmitry; Jae Kang, Young

    2013-12-09

    The effect of d{sup 1} impurity doping in Sr-hexaferrite (SrM) on the magnetic anisotropy is investigated. First-principles calculations revealed that group-V elements (V, Nb) are stabilized with co-doping of alkali elements. Na{sup 1+}/K{sup 1+} doping at Sr{sup 2+}-site is found to be critical to form the d{sup 1} impurities at Fe-site. Experimentally, Na–V doped SrM shows the intrinsic coercivity of ?5.4 kOe, which is ?300% enhancement compared to undoped SrM and comparable value to La–Co co-doped SrM. Finally, the spin-orbit coupling from non-vanishing angular momentum of d{sup 1} impurity in SrM should be a main factor for such a substantial improvement of intrinsic coercivity.

  9. Almost commuting elements in compact Lie groups

    E-print Network

    Armand Borel; Robert Friedman; John W. Morgan

    1999-07-01

    We describe the components of the moduli space of conjugacy classes of commuting pairs and triples of elements in a compact Lie group. This description is in terms of the extended Dynkin diagram of the simply connected cover, together with the coroot integers and the action of the fundamental group. In the case of three commuting elements, we compute Chern-Simons invariants associated to the corresponding flat bundles over the three-torus, and verify a conjecture of Witten which reveals a surprising symmetry involving the Chern-Simons invariants and the dimensions of the components of the moduli space.

  10. Properties of Group Five and Group Seven transactinium elements

    SciTech Connect

    Wilk, Philip A.

    2001-05-01

    The detection and positive identification of the short-lived, low cross section isotopes used in the chemical studies of the heaviest elements are usually accomplished by measuring their alpha-decay, thus the nuclear properties of the heaviest elements must be examined simultaneously with their chemical properties. The isotopes 224 Pa and 266,267 Bh have been studied extensively as an integral part of the investigation of the heaviest members of the groups five and seven of the periodic table. The half-life of 224 Pa was determined to be 855 plus/minus19 ms by measuring its alpha-decay using our rotating wheel, solid state detector system at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. Protactinium was produced by bombardment of a bismuth target. New neutron rich isotopes, 267 Bh and 266 Bh, were produced in bombardments of a 249 Bk target and their decay was observed using the rotating wheel system. The 266 Bh that was produced decays with a half-life of approximately 1 s by emission of alpha particles with an average energy of 9.25 plus/minus 0.03 MeV. 267 Bh was observed to decay with a 17 s half-life by emission of alpha-particles with an average energy of 8.83 plus/minus 0.03 MeV. The chemical behavior of hafnium, Ha (element 105) was investigated using the fast on-line continuous liquid extraction and detection system SISAK-LISSY. Hafnium was not observed in this experiment following transport and extraction. Protactinium was used as on-line test of the apparatus to determine the experimental efficiency of the entire system. Unfortunately, the amount of protactinium observed after the extraction, compared to the amount produced, was extremely small, only 2.5%. The extraction of the protactinium isotope indicated the efficiency of the apparatus was too low to observe the extraction of hafnium. The chemical behavior of oxychloride compounds of bohrium was investigated by isothermal gas adsorption chromatography in a quartz column at 180, 150, and 75 C. It was found to be less volatile than the corresponding compounds of the lighter group seven homologues, rhenium and technetium, which had been measured previously with the same apparatus. Assuming the bohrium compound to be BhO3Cl, the evaluated standard adsorption enthalpy, and delta-Hads, of BhO3Cl on the quartz surface was calculated from Monte Carlo fits to the volatility data to be -75 kJ/mol. The adsorption enthalpies for TcO3Cl and ReO3Cl are -51 and -61 kJ/mol respectively.

  11. Cold Fusion Production and Decay of Neutron-Deficient Isotopes of Dubnium and Development of Extraction Systems for Group V Elements

    SciTech Connect

    Gates, Jacklyn M.

    2008-07-31

    Excitation functions for the 1n and 2n exit channels of the 208Pb(51V,xn)259-xDb reaction were measured. A maximum cross section of the 1n exit channel of 2070+1100/-760 pb was measured at an excitation energy of 16.0 +- 1.8 MeV. For the 2n exit channel, a maximum cross section of 1660+450/-370 pb was measured at 22.0 +- 1.8 MeV excitation energy. The 1n excitation function for the 209Bi(50Ti,n)258Db reaction was remeasured, resulting in a cross section of 5480+1730/1370 pb at an excitation energy of 16.0 +- 1.6 MeV. Differences in cross section maxima are discussed in terms of the fusion probability below the barrier. The extraction of niobium (Nb) and tantalum (Ta) from hydrochloric acid and mixed hydrochloric acid/lithium chloride media by bis(2-ethylhexyl) hydrogen phosphate (HDEHP) and bis(2-ethylhexyl) hydrogen phosphite (BEHP) was studied. The goal of the experiments was to find a system that demonstrates selectivity among the members of group five of the Periodic Table and is also suitable for the study of dubnium (Db, Z = 105). Experiments with niobium and tantalum were performed with carrier (10-6 M), carrier free (10-10 M) and trace (10-16 M) concentrations of metal using hydrochloric acid solution with concentrations ranging from 1 - 11 M. The extraction of niobium and tantalum from mixed hydrochloric acid/lithium chloride media by HDEHP and BEHP as a function of hydrogen ion (H+) concentration was also investigated. The data obtained are used as the basis to discuss the speciation of niobium and tantalum under the conditions studied and to evaluate possible extraction mechanisms. The 74Se(18O,p3n)88gNb excitation function was measured to determine the best energy for producing the 88Nb used in chemistry experiments. A maximum cross section of 495 +- 5 mb was observed at an 18O energy of 74.0 MeV. The half life of 88gNb was measured and determined to be 14.56 +- 0.11 min.

  12. Fully Commutative Elements in Affine Coxeter Groups

    E-print Network

    Goubet, Olivier

    . For simplicity, we assume connected ( W irreducible) #12;Coxeter group: examples s1 sn-1 (1) An-1 s2 sisi+1si = si+1sisi+1 sisj = sjsi, |j - i| > 1 Isomorphic to the symmetric group Sn via si (i, i + 1). #12;Coxeter group: examples s1 sn-1 (1) An-1 s2 sisi+1si = si+1sisi+1 sisj = sjsi, |j - i| > 1 Isomorphic

  13. Potential Mobilization of Platinum-Group Elements by

    E-print Network

    Potential Mobilization of Platinum-Group Elements by Siderophores in Surface Environments S U S A N and Geological Sciences, University of Notre Dame, Notre Dame, Indiana 46556 The emission of platinum. Introduction The release of the platinum-group elements (PGEs) Pd, Pt, and Rh from catalytic converters is well

  14. How to efficiently select an arbitrary Clifford group element

    SciTech Connect

    Koenig, Robert; Smolin, John A.

    2014-12-15

    We give an algorithm which produces a unique element of the Clifford group on n qubits (C{sub n}) from an integer 0?i<|C{sub n}| (the number of elements in the group). The algorithm involves O(n{sup 3}) operations and provides, in addition to a canonical mapping from the integers to group elements g, a factorization of g into a sequence of at most 4n symplectic transvections. The algorithm can be used to efficiently select random elements of C{sub n} which are often useful in quantum information theory and quantum computation. We also give an algorithm for the inverse map, indexing a group element in time O(n{sup 3})

  15. Parallel and Serial Grouping of Image Elements in Visual Perception

    ERIC Educational Resources Information Center

    Houtkamp, Roos; Roelfsema, Pieter R.

    2010-01-01

    The visual system groups image elements that belong to an object and segregates them from other objects and the background. Important cues for this grouping process are the Gestalt criteria, and most theories propose that these are applied in parallel across the visual scene. Here, we find that Gestalt grouping can indeed occur in parallel in some…

  16. Structural characterization of group 4 element clusters

    NASA Astrophysics Data System (ADS)

    Shvartsburg, Alexandre Alexandrovich

    Structural elucidation of group 4 clusters has been accomplished using primarily ion mobility measurements. The observed features are assigned by comparing the mobilities evaluated for candidate geometries with the experimental data. The recent introduction of high-resolution ion mobility measurements has rendered previous methods for mobility calculations obsolete. To enable accurate interpretation of mobility data, we have developed new computational tools ensuring a realistic description of the interaction between the ion and buffer gas atoms. Some important features of these tools are the exact modeling of multiple scattering, inclusion of the long-range attractive potential due to dispersion and charge-induced dipole forces, incorporation of actual distribution of charge over the ion, and accounting for the electronic spill-out. New theoretical methods were employed to analyze the mobilities measured for group 4 cluster ions. For carbon, the composition and chemistry in fullerene plasma are of special interest. We have determined that fullerenes coalesce mainly making the [2+2] cycloadducts that anneal into near-spherical cages. However, some sizes exhibit the "ball-and-chain" dimers comprising two fullerenes connected by a chain. We have also observed the "stick" and "handle" intermediates along the fallerene road postulated in theoretical studies of fullerene formation. To aid the structural characterization of Si and Ge clusters, we have optimized their geometries for neutrals, cations, and anions. The morphologies resulting for medium-sized clusters are built on the tricapped trigonal prism subunit. These geometries agree with mobility measurements for both cations and anions. They are also supported by the data on ionization potentials of the neutrals, and dissociation energies/pathways of the cations. In particular, we have pinpointed where the growth patterns of Si and Ge species diverge. Tin cluster cations were probed by mobility measurements and found to be isomorphous to Ge species in the medium size range. A transition to near-spherical geometries gradually occurs for larger sizes. Prolate Sn clusters retain their shapes above the bulk melting point. This is the first example of melting point in clusters exceeding that of the bulk. Lead species assume compact shapes appropriate for metal clusters. Thus the transition from covalent to metallic bonding in group 4 clusters occurs between tin and lead.

  17. INTEGRATED MEMS REFLECTARRAY ELEMENTS Sean V. Hum1

    E-print Network

    Hum, Sean Victor

    element based on MEMS capacitors. The design and mea- surements of an experimental MEMS reflectarray elINTEGRATED MEMS REFLECTARRAY ELEMENTS Sean V. Hum1 , G. McFeetors2 , and M. Okoniewski2 1 Edward S various approaches for tuning reflectarray elements have been proposed, successfully demonstrated ap

  18. Methods for forming group III-V arsenide-nitride semiconductor materials

    NASA Technical Reports Server (NTRS)

    Major, Jo S. (Inventor); Welch, David F. (Inventor); Scifres, Donald R. (Inventor)

    2000-01-01

    Methods are disclosed for forming Group III--arsenide-nitride semiconductor materials. Group III elements are combined with group V elements, including at least nitrogen and arsenic, in concentrations chosen to lattice match commercially available crystalline substrates. Epitaxial growth of these III-V crystals results in direct bandgap materials, which can be used in applications such as light emitting diodes and lasers. Varying the concentrations of the elements in the III-V crystals varies the bandgaps, such that materials emitting light spanning the visible spectra, as well as mid-IR and near-UV emitters, can be created. Conversely, such material can be used to create devices that acquire light and convert the light to electricity, for applications such as full color photodetectors and solar energy collectors. The growth of the III-V crystals can be accomplished by growing thin layers of elements or compounds in sequences that result in the overall lattice match and bandgap desired.

  19. Designing Isoelectronic Counterparts to Layered Group V Semiconductors.

    PubMed

    Zhu, Zhen; Guan, Jie; Liu, Dan; Tománek, David

    2015-08-25

    In analogy to III-V compounds, which have significantly broadened the scope of group IV semiconductors, we propose a class of IV-VI compounds as isoelectronic counterparts to layered group V semiconductors. Using ab initio density functional theory, we study yet unrealized structural phases of silicon monosulfide (SiS). We find the black-phosphorus-like ?-SiS to be almost equally stable as the blue-phosphorus-like ?-SiS. Both ?-SiS and ?-SiS monolayers display a significant, indirect band gap that depends sensitively on the in-layer strain. Unlike 2D semiconductors of group V elements with the corresponding nonplanar structure, different SiS allotropes show a strong polarization either within or normal to the layers. We find that SiS may form both lateral and vertical heterostructures with phosphorene at a very small energy penalty, offering an unprecedented tunability in structural and electronic properties of SiS-P compounds. PMID:26190265

  20. Novel sp3-hybridized framework structure of group 14 elements

    NASA Astrophysics Data System (ADS)

    Nguyen, Manh Cuong; Zhao, Xin; Wang, Cai-Zhuang; Ho, Kai-Ming

    2014-03-01

    Using genetic algorithm atomic structure prediction method and first-principles calculations, we discovered a novel low-energy metastable structure of group 14 elements in P42/mnm symmetry. The P42/mnm structure is a cage-like distorted sp3-hybridized framework structure with the cage's volume ~ 4% larger than the average cage's volume of the clathrate type-I structure, indicating P42/mnm structure a good gases or metal atoms encapsulation structure. The band structure calculations show that P42/mnm Si and Ge are semiconducting with energy band gaps close to the optimal values for optoelectronic or photovoltaic applications. The metal atom encapsulation P42/mnm structure of group 14 elements could also be a candidate for rattling-mediated superconducting or ``a phonon glass and an electrical crystal'' thermoelectric materials.

  1. Homocatenation of Metal and Metalloid Main Group Elements

    NASA Astrophysics Data System (ADS)

    Hill, Michael S.

    Interest in poly(diorgano)silanes, catenated silicon compounds and heavier element analogues of alkanes has derived largely from their 1-dimensional delocalisation across the Si-Si ? framework, which affords similar properties observed for polyene and unsaturated "all organic" polymers. Although not so widely recognised or studied, similar "?-delocalised" activity may also be observed for homocatenated species of other p-block elements. In this study, a foundation for an understanding of the phenomenon of ?-delocalisation is provided through consideration of the structures, methods of synthesis and electronic behaviour of the well-established poly(diorgano)silanes. Synthetic and theoretical developments relating to analogous derivatives based upon silicon's heavier group 14 congeners are then reviewed along with the more limited examples of catenated compounds among the heavier elements of groups 15 and 13. This coverage does not dwell upon detailed aspects of structure or electronic behaviour for the individual compounds and classes of compound included. Rather, the intention is to promote something of a phenomenological awareness of a series of superficially disparate chemical systems and to encourage a more widespread appreciation of the implication that, in not displaying ?-delocalisation, it is the elements of the first full period that display the more unusual or anomalous behaviour.

  2. THE PROPORTION OF FIXED-POINT-FREE ELEMENTS OF A TRANSITIVE PERMUTATION GROUP

    E-print Network

    Jackson, David A.

    . THE PROPORTION OF FIXED-POINT-FREE ELEMENTS OF A TRANSITIVE PERMUTATION GROUP Nigel Boston the following question: if G is a transitive permutation group of degree n and A is the set of elements of G;2 FIXED-POINT-FREE ELEMENTS OF A TRANSITIVE GROUP wreath product or a direct product of permutation groups

  3. Platinum group elements in mantle melts and mantle samples

    NASA Astrophysics Data System (ADS)

    Barnes, Stephen J.; Mungall, James E.; Maier, Wolfgang D.

    2015-09-01

    A large data compilation has been assembled of platinum group element (PGE) analyses in mantle melts and mantle rocks, the latter including an assortment of xenoliths and obducted mantle massifs. The degree of correlation has been investigated among the PGEs and with other major element variables such as Al2O3, TiO2 and Mg number, and the results are considered in the context of the current paradigm for the behaviour of highly siderophile elements in the silicate Earth. Primitive mantle melts have a wide range of PGE contents. Komatiites have the highest abundances of all the PGEs, show the strongest correlations between Pt and Rh, Pt and Pd and between the iridium-group PGEs Ir, Ru and Os (IPGEs). Most basalts of all affinities have lower levels of Pt and Pd and much lower levels of Ir, Ru and Os than komatiites. Within the basalt grouping Rh has stronger affinities with the IPGEs. Picrites and Archaean basalts are intermediate between these two groups. MORBs and a small proportion of continental LIP basalts show strong depletions in all PGEs attributable to retention of sulfide in their mantle source rocks, or sulfide liquid fractionation on ascent. The degree of PGE depletion in other basalts is probably attributable to equilibration with sulfide, but is less than would be expected under conventional models of sulfide extraction, and is instead attributed to mixing of magmas generated at variable depths incorporating both sulfide-saturated and undersaturated components. Basalts with Pt and Pd contents higher than typical komatiites are rare, a notable example being B1-type parent magmas to the Bushveld Complex, which have komatiite-like relative PGE abundances and Pt, Pd and Rh abundances up to a factor of two higher than komatiites for comparable Ti contents. The mantle composition array as a whole is characterized by variable degrees of depletion of Pt, Pd and Rh in Al-poor, melt-depleted harzburgite/dunite lithologies; lack of depletion in these elements in Al-bearing lherzolites; and a lack of systematic variation in IPGEs across this range. Strongest correlations across the entire set are observed between Ir, Ru and Os; and between Pt and Rh. Melt-depleted cratonic mantle samples are notably more deficient in Pd than in Pt, but comparable Pd-enriched components are not represented in the available data from continental environments. The only group of mantle melts that systematically record high Pd/Pt ratios are MORBs; if these are indeed the complement of the depleted cratonic mantle suite then the melt depletion recorded by the cratonic mantle suite occurred at low pressure prior to tectonic underplating of the depleted lithosphere beneath the cratons. A filtered subset of orogenic peridotite compositions that are thought not to have been affected by significant extents of melt extraction or metasomatic refertilization have median concentrations of 3.9 ppb Os, 2.9 ppb Ir, 6.3 ppb Ru, 1.0 ppb Rh, 6.2 ppb Pt, 5.4 ppb Pd, and Cu/Pd ratio of 5500, which we consider to be representative of the modern convecting mantle. The convecting mantle has PGE proportions closely resembling those of lunar impact breccias, diverging considerably from chondritic proportions and attributable to the presence of a late veneer-derived, predominantly sulfide-hosted component. The compositions of mantle peridotites show considerable scatter attributable to the combined effects of measurement error and a strong covariance due to a heterogeneous distribution of sulfide in the small samples typically chosen for pulverization. The intensity of the covariance between all of the PGE due to sampling error gives a false impression of a genetic trend toward highly enriched PGE in some samples which could be mistaken for the effects of metasomatism; however no plausible metasomatic process would be expected to retain the tight interelement correlations shown.

  4. A Renormalisation Group Method. V. A Single Renormalisation Group Step

    NASA Astrophysics Data System (ADS)

    Brydges, David C.; Slade, Gordon

    2015-05-01

    This paper is the fifth in a series devoted to the development of a rigorous renormalisation group method applicable to lattice field theories containing boson and/or fermion fields, and comprises the core of the method. In the renormalisation group method, increasingly large scales are studied in a progressive manner, with an interaction parametrised by a field polynomial which evolves with the scale under the renormalisation group map. In our context, the progressive analysis is performed via a finite-range covariance decomposition. Perturbative calculations are used to track the flow of the coupling constants of the evolving polynomial, but on their own perturbative calculations are insufficient to control error terms and to obtain mathematically rigorous results. In this paper, we define an additional non-perturbative coordinate, which together with the flow of coupling constants defines the complete evolution of the renormalisation group map. We specify conditions under which the non-perturbative coordinate is contractive under a single renormalisation group step. Our framework is essentially combinatorial, but its implementation relies on analytic results developed earlier in the series of papers. The results of this paper are applied elsewhere to analyse the critical behaviour of the 4-dimensional continuous-time weakly self-avoiding walk and of the 4-dimensional -component model. In particular, the existence of a logarithmic correction to mean-field scaling for the susceptibility can be proved for both models, together with other facts about critical exponents and critical behaviour.

  5. Doping of indium phosphide with group IV elements

    SciTech Connect

    Zakharenkov, L.F.; Samorukov, B.E.; Zykov, A.M.

    1985-06-01

    This paper studies the doping of single crystals of indium phosphide (InP) with group IV elements using data obtained by measuring the total charge concentration of additives and carriers. Single crystals of indium phosphide were grown by the Czochralski method from liquid melts with a liquid hermetic seal in quartz cubicles. The total impurity concentration was determined by atomic-absorption analysis with + or - 10% error. In order to explain the behavior of germanium and tin in indium phosphide, the authors consider the bond energies of additives in indium phosphide and their tetrahedral radii. The authors conclude that the established higher amphoteric character of germanium with respect to tin is probably explained by the moduli of elasticity of the doped crystal.

  6. Mahowaldean families of elements in stable homotopy groups revisited

    NASA Astrophysics Data System (ADS)

    Hunter, David J.; Kuhn, Nicholas J.

    1999-09-01

    In the mid 1970s Mark Mahowald constructed a new infinite family of elements in the 2-component of the stable homotopy groups of spheres, [eta]j[set membership][pi]Sj2 (S0)(2) [M]. Using standard Adams spectral sequence terminology (which will be recalled in Section 3 below), [eta]j is detected by h1hj[set membership]Ext2,*[script A] (Z/2, Z/2). Thus he had found an infinite family of elements all having the same Adams filtration (in this case, 2), thus dooming the so-called Doomsday Conjecture. His constructions were ingenious: his elements were constructed as composites of pairs of maps, with the intermediate spaces having, on one hand, a geometric origin coming from double loopspace theory and, on the other hand, mod2 cohomology making them amenable to Adams Spectral Sequence analysis and suggesting that they were related to the new discovered Brown-Gitler spectra [BG].In the years that followed, various other related 2-primary infinite families were constructed, perhaps most notably (and correctly) Bruner's family detected by h2h2j[set membership] Ext3,*[script A](Z/2, Z/2) [B]. An odd prime version was studied by Cohen [C], leading to a family in [pi]S[low asterisk](S0)(p) detected by h0bj[set membership] Ext3,*[script A] (Z/p, Z/p) and a filtration 2 family in the stable homotopy groups of the odd prime Moore space. Cohen also initiated the development of odd primary Brown-Gitler spectra, completed in the mid 1980s, using a different approach, by Goerss [G], and given the ultimate ‘modern’ treatment by Goerss, Lannes and Morel in the 1993 paper [GLM]. Various papers in the late 1970s and early 1980s, e.g. [BP, C, BC], related some of these to loopspace constructions.Our project originated with two goals. One was to see if any of the later work on Brown-Gitler spectra led to clarification of the original constructions. The other was to see if taking advantage of post Segal Conjecture knowledge of the stable cohomotopy of the classifying space BZ/p would help in constructing new families at odd primes, in particular a conjectural family detected by h0hj[set membership] Ext2,*[script A] (Z/p, Z/p). (This followed a paper [K1] by one of us on 2 primary families from this point of view.)

  7. Research papers Distribution of platinum-group and chalcophile elements in the Aguablanca NiCu

    E-print Network

    Research papers Distribution of platinum-group and chalcophile elements in the Aguablanca Ni: Accepted 9 February 2011 Available online 15 February 2011 Editor: L. Reisberg Keywords: Platinum-group elements Aguablanca Laser ablation Base-metal sulfides Pyrite The concentrations of platinum-group elements

  8. FREELY BRAIDED ELEMENTS IN COXETER GROUPS, II R.M. Green and J. Losonczy

    E-print Network

    Green, Richard M.

    FREELY BRAIDED ELEMENTS IN COXETER GROUPS, II R.M. Green and J@e-math.ams.org Abstract. We continue the study of freely braided elements of simply lace* *d Coxeter groups, which classes of reduced expressions for an element of a * *simply laced Coxeter group is shown

  9. Thermodynamic properties of the Group 1A elements

    SciTech Connect

    Alcock, C.B.; Itkin, V.P.; Chase, M.W.

    1994-05-01

    This review describes thermodynamic properties of condensed phases of the alkali metals, excluding francium for which the amount of information is too limited. The properties considered are: heat capacities from 0 to 1600 K, temperatures and enthalpies of fusion and martensitic transformation in Li and Na; discussion of the Debye temperature and electronic heat capacity coefficient at absolute zero temperature is also included. The paper is the second part of a series. Similar to previous assessment of the IIA group [93ALC/CHA], this paper considers original studies, especially with respect to factors which influence the accuracy and reliability of results. Recommendations derived from such analyses are compared with most advanced previous reviews made at the Institute for High Temperatures (Moscow) [70SHP/YAK], [82GUR] and the National Institute of Standards and Technology (Washington) [85JAN]. The properties of individual elements of the group are compared and suggestions are made for experimental studies which should improve poorly measured quantities. The review is supplemented by an IBM PC database which contains references, assessed data, brief description of studies and has facilities for fitting and plotting of data and for adding new information.

  10. Comprehensive Analyses of the Spectra of Iron-group Elements

    NASA Astrophysics Data System (ADS)

    Nave, Gillian; Sansonetti, Craig J; Pickering, Juliet C; Liggins, Florence

    2014-06-01

    For many decades, the Atomic Spectroscopy Group at NIST has measured atomic data of vital use to astronomy and other fields using high resolution spectrometers that are found in few other places in the world. These now include the 2-m Fourier transform (FT) spectrometer covering the region 285 nm to 5500 nm, the FT700 vacuum ultraviolet (VUV) FT spectrometer covering the region 143 nm to 900 nm, and a 10.7-m normal incidence spectrograph (NIVS) covering 30 nm to 500 nm. Recent work focused on the measurement and analysis of wavelengths and energy levels of iron-group elements to provide extensive data for the analysis of astrophysical spectra. Our comprehensive linelist for Fe II from 90 nm to 5500 nm contains over 13 600 lines with order of magnitude improvements in the wavelengths compared to previous work [Nave & Johansson, ApJSS 204, 1(2013)]. The spectra were observed in high-current continuous and pulsed hollow cathode (HCL) discharges using FT spectrometers and our NIVS spectrograph. A similar analysis of Cr II contains over 5300 lines and extends the knowledge of this spectrum to the previously unobserved region between 731 nm at 5500 nm [Sansonetti, Nave, Reader & Kerber, ApJSS 202, 15 (2012); Sansonetti & Nave, ApJSS (in prep.)]. Our analysis of the Co III spectrum contains 750 lines observed in Penning discharge lamps and an additional 900 lines compiled from previous work, including Ritz wavelengths, optimized energy levels, and calculated log(gf) values [Smillie, Pickering, Nave & Smith, ApJSS (in prep.)]. NIST and ICL are currently collaborating to complete the measurement and analysis of wavelengths, energy levels, and hyperfine structure parameters for all singly-ionized iron-group elements of astrophysical interest, covering the wavelength range 80 nm to 5500 nm. This project uses archival data from FT spectrometers at NIST, ICL and Kitt Peak National Observatory, with additional spectra of HCL and Penning discharge sources taken using our FT and NIVS spectrometers. Current work includes the spectra of Mn I, Mn II, Ni II, Sc II, and Co III. This work was partially supported by NASA, the STFC and PPARC (UK), the Royal Society of the UK, and the Leverhulme Trust.

  11. Platinum-group elements: so many excellent properties

    USGS Publications Warehouse

    Zientek, Michael L.; Loferski, Patricia J.

    2014-01-01

    The platinum-group elements (PGE) include platinum, palladium, rhodium, ruthenium, iridium, and osmium. These metals have similar physical and chemical properties and occur together in nature. The properties of PGE, such as high melting points, corrosion resistance, and catalytic qualities, make them indispensable to many industrial applications. PGE are strategic and critical materials for many nations because they are essential for important industrial applications but are mined in a limited number of places and have no adequate substitutes. Exploration and mining companies have found approximately 104,000 metric tons of PGE (with minor gold) in mineral deposits around the world that could be developed. For PGE, almost all known production and resources are associated with three geologic features: the Bushveld Complex, a layered mafic-to-ultramafic intrusion in South Africa; the Great Dyke, a layered mafic-to-ultramafic intrusion in Zimbabwe; and sill-like intrusions associated with flood basalts in the Noril’sk-Talnakh area, Russia. To help predict where PGE supplies might be located, USGS scientists study how and where PGE resources are concentrated in the Earth's crust and use that knowledge to assess the likelihood that undiscovered PGE deposits may exist. Techniques used for assessing mineral resources were developed by the USGS to support the stewardship of Federal lands and evaluate mineral resource availability in a global context. The USGS also compiles statistics and information on the worldwide supply, demand, and flow of PGE. These data are all used to inform U.S. national policymakers.

  12. Fe-Group Elements in the Metal-Poor Star HD 84937: Abundances and their Implications

    NASA Astrophysics Data System (ADS)

    Sneden, Chris; Cowan, John J.; Kobayashi, Chiaki; Pignatari, Marco; Lawler, James E.; Den Hartog, Elizabeth; Wood, Michael P.

    2016-01-01

    We have derived accurate relative abundances of the Fe-group elements Sc through Zn in the very metal-poor main-sequence turnoff star HD 84937. For this study we analyzed high resolution, high signal-to-noise HST/STIS and VLT/UVES spectra over a total wavelength range 2300-7000 Å. We employed only recent or newly-applied reliable laboratory transition data for all species. Abundances from more than 600 lines of non-Fe species were combined with about 550 Fe lines in HD 84937 to yield abundance ratios of high precision. From parallel analyses of solar photospheric spectra we also derived new solar abundances of these elements. This in turn yielded internally-consistent relative HD 84937 abundances with respect to the Sun. For seven of the ten Fe-group elements the HD 84937 abundances were from both neutral and ionized transitions. In all of these cases the neutral and ionized species yield the same abundances within the measurement uncertainties. Therefore standard Saha ionization balance appears to hold in the HD 84937 atmosphere. We derived metallicity [Fe/H] = -2.32 with sample standard deviation of 0.06. Solid evidence is seen for departures from the solar abundance mix in HD 84937, for example [Co/Fe] = +0.14, [Cu/Fe] = -0.83, and <[Sc,Ti,V/Fe]> = +0.31. Combining our Sc, Ti, and V abundances for this star with those from large-sample spectroscopic surveys suggests that these elements are positively correlated in stars with [Fe/H] < -2. HD 84937 is unusually enriched in Sc, Ti, and V. Our analysis strongly suggests that different types of supernovae with a large scatter of explosion energies and asymmetries contributed to the creation of the Fe-group elements early in the Galaxy's history.This work has been supported in part by NASA grant NNX10AN93G (J.E.L.), by NSF grants AST-1211055 (J.E.L.), AST-1211585 (C.S.), PHY-1430152 (through JINA, J.J.C. and M.P.), EU MIRGCT-2006-046520 (M.P.), and by the ``Lendlet-2014'' Programme of the Hungarian Academy of Sciences (M.P.) and from SNF (Switzerland, M.P.).

  13. Determination of the CKM Element V(Ub)

    SciTech Connect

    Fortin, Dominique; /Victoria U.

    2007-04-06

    The precise determination of the CKM matrix element |V{sub ub}| is crucial in testing the Standard Model mechanism for CP violation. From a sample of 88 million B{bar B} pairs collected with the BABAR detector, charmless semileptonic B decays are selected using simultaneous requirements on the electron energy, E{sub e}, and the invariant mass squared of the electron-neutrino pair, q{sup 2}. The partial branching fraction, unfolded for detector effects, is determined in a region of the q{sup 2}-E{sub e} plane where the dominating semileptonic decays to charm mesons are highly suppressed. Theoretical calculations based on the Heavy Quark Expanion allows for a determination of |V{sub ub}| = (3.95 {+-} 0.27{sub -0.42}{sup +0.58} {+-} 0.25) x 10{sup -3}, where the errors represent experimental, heavy quark parameters and theoretical uncertainties, respectively.

  14. Summary of the TeV33 working group

    SciTech Connect

    Bagley, P.P.; Bieniosek, F.M.; Colestock, P.

    1996-10-01

    This summary of the TeV33 working group at Snowmass reports on work in the areas of Tevatron store parameters, the beam-beam interaction, Main Injector intensity (slip stacking), antiproton production, and electron cooling.

  15. Design, synthesis, and properties of phthalocyanine complexes with main-group elements showing main absorption and fluorescence beyond 1000 nm.

    PubMed

    Furuyama, Taniyuki; Satoh, Koh; Kushiya, Tomofumi; Kobayashi, Nagao

    2014-01-15

    We present a comprehensive description of the unique properties of newly developed phthalocyanines (Pcs) containing main-group elements that absorb and emit in the near-IR region. Group 16 (S, Se, and Te) elements and group 15 (P, As, and Sb) elements were used as peripheral and central (core) substituents. With the introduction of group 16 elements into free-base Pc, a red-shift of the Q-band was observed, as a result of the electron-donating ability of group 16 elements particularly at the ? positions. An X-ray crystallographic analysis of ?-ArS-, ArSe-, and ArTe-linked free-base Pcs was also successfully performed, and the relationship between structure and optical properties was clarified. When a group 15 element ion was introduced into the center of the Pc ring, the resulting Pcs showed a single Q-band peak beyond 1000 nm (up to 1056 nm in CH2Cl2). In particular, [(ArS)8PcP(OMe)2](+) and [(ArS)8PcAs(OMe)2](+) exhibited a distinct fluorescence in the 960-1400 nm region with moderate quantum yields. The atomic radius of the group 15 element is important for determining the Pc structure, so that this can be controlled by the choice of group 15 elements. Electrochemical data revealed, while MO calculations suggested, that the red-shift of the Q-band is attributable to a decrease of the HOMO-LUMO gap due to significant and moderate stabilization of the LUMO and HOMO, respectively. The effect of peripheral substutuents and a central P(V) ion on the Q-band shift was independently predicted by MO calculations, while the magnitude of the total calculated shift was in good agreement with the experimental observations. The combination of spectral, electrochemical, and theoretical considerations revealed that all of the central group 15 elements, peripheral group 16 elements, and their positions are necessary to shift the Q-band beyond 1000 nm, indicating that the substitution effects of group 15 and 16 elements act synergistically. The Pcs having Q-bands beyond 1000 nm in this study also had stability under aerobic conditions comparative to that of CuPc, which is presently being widely used in consumer products. PMID:24328229

  16. New laboratory atomic data for neutral, singly and doubly ionised iron group elements for astrophysics applications

    NASA Astrophysics Data System (ADS)

    Pickering, Juliet C.; Nave, Gillian; Liggins, Florence; Clear, Christian; Ruffoni, Matthew; Sansonetti, Craig

    2015-08-01

    We present new laboratory spectroscopic measurements to produce atomic data for astrophysically important species: neutral, singly and doubly ionised iron group elements.We use high resolution Fourier Transform Spectrometry (FTS) (resolving power up to 2x106 at 200nm) to measure atomic spectra, giving accurate line wavelengths (to a few parts in 108), atomic energy levels, hyperfine structure splitting and log gfs (accurate to a few %) (Ruffoni et al this meeting). These data are vital for astrophysical spectral analyses for: line identification, spectrum synthesis, elemental abundance determinations [eg 1], and disentangling of blends etc. It is not possible to theoretically calculate these atomic data to the accuracy needed for modern astrophysics applications.At Imperial College we have a unique visible-VUV FT spectrometer with short wavelength cut-off of 135nm. We supplement FTS data at shorter wavelengths with spectra recorded on the NIST 10.7m grating spectrograph (with phosphor image or photographic plates) and at longer wavelengths in the IR we use the NIST IR FT spectrometer.An elemental spectrum may contain thousands of spectral lines from the IR to VUV. We use these wavelengths to correct known atomic energy levels, and search for new atomic levels. The result is a classified linelist and accurate atomic energy levels.We present progress on iron group element atomic energy levels and wavelengths for V I and V II [2,3], Co III [4], Cr I, Mn I and Mn II, and Ni II.This work is supported by STFC(UK), The Leverhulme Trust, The Royal Society and NASA.References[1] Bergemann M, Pickering JC & Gehren T,“NLTE analysis of Co I/Co II lines in spectra of cool stars with new laboratory hyperfine splitting constants",MNRAS 401(2) 1334 (2010)[2] Thorne AP, Pickering JC & Semeniuk J,“The spectrum and term analysis of V II”, ApJS 207,13 (2013)[3] Thorne AP, Pickering JC & Semeniuk J,“The spectrum and term analysis of V I",ApJS 192,11 (2011)[4] Smillie DG, Pickering JC, Nave G & Smith PL,“The Spectrum and Term Analysis of Co III Measured using Fourier Transform and Grating Spectroscopy”,ApJS submitted

  17. The Abundances of the Fe Group Elements in Early B Stars in the Magellanic Clouds and Bridge

    NASA Astrophysics Data System (ADS)

    Peters, Geraldine J.; Adelman, Saul J.

    2016-01-01

    The abundances of three Fe Group elements (V, Cr, and Fe) in 9 early main-sequence band B stars in the LMC, 7 in the SMC , and two in the Magellanic Bridge have been determined from archival FUSE observations and the Hubeny/Lanz NLTE programs TLUSTY/SYNSPEC. Lines from the Fe group elements, except for a few weak multiplets of Fe III, are not observable in the optical spectral region. The best set of lines in the FUSE spectral region are Fe III (UV1), V III 1150 Å, and Cr III 1137 Å. The abundances of these elements in early B stars are a marker for recent SNe Ia activity, as a single exploding white dwarf can deliver 0.5 solar masses of Ni-56 that decays into Fe to the ISM. The Fe group abundances in an older population of stars primarily reflect SNe II activity, in which a single explosion delivers only 0.07 solar masses of Ni-56 to the ISM (the rest remains trapped in the neutron star). The abundances of the Fe group elements in early B stars not only track SNe Ia activity but are also important for computing evolutionary tracks for massive stars. In general, the Fe abundance relative to the sun's value is comparable to the mean abundances for the lighter elements in the Clouds/Bridge but the values of [V,Cr/Fe]sun are smaller. This presentation will discuss the spatial distribution of the Fe Group elements in the Magellanic Clouds, and compare it with our galaxy in which the abundance of Fe declines with radial distance from the center. Support from NASA grants NAG5-13212, NNX10AD66G, STScI HST-GO-13346.22, and USC's Women in Science and Engineering (WiSE) program is greatly appreciated.

  18. KASCADE-Grande measurements of energy spectra for elemental groups of cosmic rays

    E-print Network

    Fuhrmann, D; Arteaga-Velazquez, J C; Bekk, K; Bertaina, M; Bluemer, J; Bozdog, H; Brancus, I M; Cantoni, E; Chiavassa, A; Cossavella, F; Curcio, C; Daumiller, K; de Souza, V; Di Pierro, F; Doll, P; Engel, R; Engler, J; Fuchs, B; Gils, H J; Glasstetter, R; Grupen, C; Haungs, A; Heck, D; Hoerandel, J R; Huber, D; Huege, T; Kampert, K -H; Kang, D; Klages, H O; Link, K; Luczak, P; Ludwig, M; Mathes, H J; Mayer, H J; Melissas, M; Milke, J; Mitrica, B; Morello, C; Oehlschlaeger, J; Ostapchenko, S; Palmieri, N; Petcu, M; Pierog, T; Rebel, H; Roth, M; Schieler, H; Schoo, S; Schroeder, F G; Sima, O; Toma, G; Trinchero, G C; Ulrich, H; Weindl, A; Wochele, D; Wochele, J

    2013-01-01

    The KASCADE-Grande experiment, located at KIT-Karlsruhe, Germany, consists of a large scintillator array for measurements of charged particles, N_ch, and of an array of shielded scintillation counters used for muon counting, N_mu. KASCADE-Grande is optimized for cosmic ray measurements in the energy range 10 PeV to 1000 PeV, thereby enabling the verification of a knee in the iron spectrum expected at approximately 100 PeV. Exploring the composition in this energy range is of fundamental importance for understanding the transition from galactic to extragalactic cosmic rays. Following earlier studies of elemental spectra reconstructed in the knee energy range from KASCADE data, we have now extended these measurements to beyond 100 PeV. By analysing the two-dimensional shower size spectrum N_ch vs. N_mu, we reconstruct the energy spectra of different mass groups by means of unfolding methods. The procedure and its results, giving evidence for a knee-like structure in the spectrum of iron nuclei, will be presente...

  19. Trace element seasonality in marine macroalgae of different functional-form groups.

    PubMed

    Malea, Paraskevi; Chatziapostolou, Anastasia; Kevrekidis, Theodoros

    2015-02-01

    Novel information on the seasonality of element accumulation in seaweeds is provided. Seasonal patterns of As, Ba, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Se, Sr, U, V and Zn concentrations in macroalgae belonging to different functional-form groups (Ulva intestinalis, Ulva rigida, Codium fragile, Gracilaria gracilis) from the Thessaloniki Gulf, Aegean Sea were determined and compared. Uni- and multivariate data analyses were applied. Element concentrations generally decreased during spring and/or summer, probably due to the growth effect, but a reverse trend, particularly in Ulva species, was also observed. Most elements (Cd, Co, Cr, Cu, Mo, Ni, Pb, Sr) in Ulva species displayed a comparatively low monthly variability, indicating that the extent of seasonal variation is closely related to thallus morphology and growth strategy. In particular, these data suggest that Cd, Co, Cr, Cu, Mo, Ni, Pb and Sr contents in fast-growing, sheet-like macroalgae are less influenced by the season, compared to their contents in coarsely-branched and thick-leathery macroalgae; therefore, sheet-like macroalgae may be more appropriate to be used in biomonitoring of coastal waters. The data presented could be utilized in the development of biomonitoring programmes for the protection of coastal environments. PMID:25460058

  20. Elements of Mathematics, Book 10: Groups and Rings.

    ERIC Educational Resources Information Center

    Exner, Robert; And Others

    One of 12 books developed for use with the core material (Book O) of the Elements of Mathematics Program, this text covers material well beyond the scope of the usual secondary mathematics sequences. These materials are designed for highly motivated students with strong verbal abilities; mathematical theories and ideas are developed through…

  1. Evaluating Experimental Elements and Stimulating Research in the Teaching of Group Counseling.

    ERIC Educational Resources Information Center

    Pistole, M. Carole; Filer, Rex D.

    1991-01-01

    Devised method for evaluating the experiential elements used in teaching group counseling. Analyzed questionnaire administered to group theories class and group dynamics class. Findings suggest that, in general, the experiential strategies were perceived by students as useful in learning group counseling concepts. (Author/PVV)

  2. Report of the IAU/IAG Working Group on cartographic coordinates and rotational elements: 2006

    USGS Publications Warehouse

    Seidelmann, P.K.; Archinal, B.A.; A'Hearn, M.F.; Conrad, A.; Consolmagno, G.J.; Hestroffer, D.; Hilton, J.L.; Krasinsky, G.A.; Neumann, G.; Oberst, J.; Stooke, P.; Tedesco, E.F.; Tholen, D.J.; Thomas, P.C.; Williams, I.P.

    2007-01-01

    Every three years the IAU/IAG Working Group on Cartographic Coordinates and Rotational Elements revises tables giving the directions of the poles of rotation and the prime meridians of the planets, satellites, minor planets, and comets. This report introduces improved values for the pole and rotation rate of Pluto, Charon, and Phoebe, the pole of Jupiter, the sizes and shapes of Saturn satellites and Charon, and the poles, rotation rates, and sizes of some minor planets and comets. A high precision realization for the pole and rotation rate of the Moon is provided. The expression for the Sun's rotation has been changed to be consistent with the planets and to account for light travel time ?? 2007 Springer Science+Business Media B.V.

  3. KASCADE-Grande measurements of energy spectra for elemental groups of cosmic rays

    E-print Network

    :,; Arteaga-Velàzquez, J C; Bekk, K; Bertaina, M; Blümer, J; Bozdog, H; Brancus, I M; Cantoni, E; Chiavassa, A; Cossavella, F; Daumiller, K; de Souza, V; Di Pierro, F; Doll, P; Engel, R; Engler, J; Finger, M; Fuchs, B; Fuhrmann, D; Gils, H J; Glasstetter, R; Grupen, C; Haungs, A; Heck, D; Hörandel, J R; Huber, D; Huege, T; Kampert, K -H; Kang, D; Klages, H O; Link, K; ?uczak, P; Ludwig, M; Mathes, H J; Mayer, H J; Melissas, M; Milke, J; Mitrica, B; Morello, C; Oehlschläger, J; Ostapchenko, S; Palmieri, N; Petcu, M; Pierog, T; Rebel, H; Roth, M; Schieler, H; Schoo, S; Schröder, F G; Sima, O; Toma, G; Trinchero, G C; Ulrich, H; Weindl, A; Wochele, J; Wommer, M; Zabierowski, J

    2013-01-01

    The KASCADE-Grande air shower experiment [W. Apel, et al. (KASCADE-Grande collaboration), Nucl. Instrum. Methods A 620 (2010) 202] consists of, among others, a large scintillator array for measurements of charged particles, Nch, and of an array of shielded scintillation counters used for muon counting, Nmu. KASCADE-Grande is optimized for cosmic ray measurements in the energy range 10 PeV to about 2000 PeV, where exploring the composition is of fundamental importance for understanding the transition from galactic to extragalactic origin of cosmic rays. Following earlier studies of the all-particle and the elemental spectra reconstructed in the knee energy range from KASCADE data [T. Antoni, et al. (KASCADE collaboration), Astropart. Phys. 24 (2005) 1], we have now extended these measurements to beyond 200 PeV. By analysing the two-dimensional shower size spectrum Nch vs. Nmu for nearly vertical events, we reconstruct the energy spectra of different mass groups by means of unfolding methods over an energy rang...

  4. Current Light Elements of the ? Scuti Star V393 Carinae

    NASA Astrophysics Data System (ADS)

    Axelsen, R. A.

    2014-12-01

    V393 Carinae is a 7th magnitude delta Scuti star which has a principal period of 0.1413 d and an amplitude of 0.2 magnitude in V. Previous publications have suggested the existence of a second period, but its duration has so far evaded discovery. In view of the uncertainty, and since the only two papers on this star were published in 1984 and 2001, DSLR photometry was performed to obtain time series data. Images were taken during 6 nights from December 2013 to March 2014. The data were analyzed using a discrete Fourier transform, which yielded a principal frequency of 7.07727 (± 0.00005) cycles/day, corresponding to a period of 0.141297 (± 0.000001) day. Prewhitening for this frequency revealed a harmonic frequency precisely twice that of the principal, but no further dominant frequencies could be found. O-C diagrams suggested that it would appropriate to derive a new linear ephemeris from three times of maximum obtained by another author from 1977 to 1979, combined with the 6 new times of maximum reported in this paper. The light elements are: Tmax = HJD 2456732.0484 (6) + 0.14129328 (1). It is concluded that the current principal period of this star is almost identical to the period determined approximately 37 years ago. The issue of a second period is unresolved. None was detected, but it cannot be excluded that a second pulsation frequency of low amplitude could be hidden due to a low signal to noise ratio.

  5. 20142015 Verification Worksheet Dependent Student-Tracking Group V3

    E-print Network

    2014­2015 Verification Worksheet Dependent Student- Tracking Group V3 Your 2014­2015 Free (include apt. no.) Student's Date of Birth City State Zip Student's Email Address Student's Phone Number Student's Alternate or Cell Phone Number B. Child Support Paid Check the box that applies: No child

  6. 20142015 Verification Worksheet Independent Student -Tracking Group V3

    E-print Network

    2014­2015 Verification Worksheet Independent Student - Tracking Group V3 Your 2014­2015 Free apt. no.) Student's Date of Birth City State Zip Student's Email Address Student's Phone Number Student's Alternate or Cell Phone Number B. Child Support Paid Check the appropriate box below: No child

  7. 20142015 Verification Worksheet Independent Student -Tracking Group V4

    E-print Network

    2014­2015 Verification Worksheet Independent Student - Tracking Group V4 Your 2014­2015 Free apt. no.) Student's Date of Birth City State Zip Student's Email Address Student's Phone Number Student's Alternate or Cell Phone Number B. Supplemental Nutrition Assistance Program Check

  8. 20152016 Verification Worksheet Independent Student -Tracking Group V3

    E-print Network

    2015­2016 Verification Worksheet Independent Student - Tracking Group V3 Your 2015­2016 Free apt. no.) Student's Date of Birth City State Zip Student's Email Address Student's Phone Number Student's Alternate or Cell Phone Number B. Child Support Paid Check the appropriate box below: No child

  9. 20142015 Verification Worksheet Dependent Student -Tracking Group V4

    E-print Network

    2014­2015 Verification Worksheet Dependent Student - Tracking Group V4 Your 2014­2015 Free (include apt. no.) Student's Date of Birth City State Zip Student's Email Address Student's Phone Number Student's Alternate or Cell Phone Number Parent's Other Information to Be Verified B. Supplemental

  10. Matrix Airy functions for compact Lie groups V. S. Varadarajan

    E-print Network

    Varadarajan, Veeravalli S.

    student Rahul Fernandez. #12;The original Airy function First discovery due to Sir George Biddell AiryMatrix Airy functions for compact Lie groups V. S. Varadarajan University of California, Los Angeles, CA, USA Los Angeles, November 12, 2008 #12;Abstract The classical Airy function and its many

  11. Platinum-group element resources in podiform chromitites from California and Oregon.

    USGS Publications Warehouse

    Page, N.J.; Singer, D.A.; Moring, B.C.; Carlson, C.A.; McDade, J.M.; Wilson, S.A.

    1986-01-01

    Assays of Pt, Pd, Rh and Ir from approx 280 podiform chromite deposits in Palaeozoic and Mesozoic ophiolites are statistically analysed to estimate their possible by-product value from mining the chromite. The platinum-group elements occur in discrete platinum-group minerals, and in solid solution in Cu-Ni-Fe sulphides. Low grades and small amounts of total platinum-group elements in podiform chromite deposits imply a small resource. -G.J.N.

  12. Spectroscopy of XY 3Z (C 3 v) radicals with an odd number of electrons: A tensorial formalism adapted to the SU(2)?CI?C?vS?C3vS group chain

    NASA Astrophysics Data System (ADS)

    El Hilali, A.; Boudon, V.; Loëte, M.

    2006-09-01

    A tensorial formalism adapted to the case of XY 3Z symmetric tops with half integer angular momenta is proposed as an extension of the formalism for the group chain O (3) ? C? v ? C3 v developed in a recent paper [A. El Hilali, V. Boudon, M. Loëte, J. Mol. Spectrosc. 234 (2005) 113-121]. We use the chain SU(2)?CI?C?vS?C3vS, where GS ( G being C? v or C3 v) is the G point group with its spinorial representations. Coupling coefficients and formulas for the computation of matrix elements of the tensor operators are derived for this chain. A deduction of coupling coefficients (Clebsch-Gordan, 6 C, 9 C, …) and similar formulas is proposed for the group C3vS itself.

  13. GARSIDE FAMILIES IN ARTINTITS MONOIDS AND LOW ELEMENTS IN COXETER GROUPS

    E-print Network

    Dehornoy, Patrick

    GARSIDE FAMILIES IN ARTIN­TITS MONOIDS AND LOW ELEMENTS IN COXETER GROUPS PATRICK DEHORNOY, MATTHEW DYER, AND CHRISTOPHE HOHLWEG R´esum´e. We show that every finitely generated Artin­Tits group admits under suffix and join with respect to the right weak order. 1. Introduction Artin­Tits groups, also

  14. Re-187 Os-187 Isotopic and Highly Siderophile Element Systematics of Group IVB Irons

    NASA Technical Reports Server (NTRS)

    Honesto, J.; McDonough, W. F.; Walker, R. J.; McCoy, T. J.; Ash, R. D.

    2005-01-01

    Study of the magmatic iron meteorite groups permits constraints to be placed on the chemical and isotopic composition of parent bodies, and the timing of, and crystal-liquid fractionation processes involved in the crystallization of asteroidal cores. Here we examine Re-Os isotopic and trace elemental systematics of group IVB irons. Compared to most irons, the irons comprising this group are enriched in some of the most refractory siderophile elements, yet highly-depleted in most volatile siderophile elements. These characteristics have been attributed to processes such as high temperature condensation of precursor materials and oxidation in the parent body. Most recently it has been suggested that both processes may be involved in the chemical complexity of the group. Here, high precision isotopic and highly siderophile element (HSE) concentrations are used to further examine these possible origins, and the crystallization history of the group. In addition, we have begun to assess the possibility of relating certain ungrouped irons with major groups via multi-element, trace element modeling. In a companion abstract, the isotopic and trace element systematics of the ungrouped iron Tishomingo are compared with the IVB irons.

  15. Integrated learning in practical machine element design course: a case study of V-pulley design

    NASA Astrophysics Data System (ADS)

    Tantrabandit, Manop

    2014-06-01

    To achieve an effective integrated learning in Machine Element Design course, it is of importance to bridge the basic knowledge and skills of element designs. The multiple core learning leads the pathway which consists of two main parts. The first part involves teaching documents of which the contents are number of V-groove formulae, standard of V-grooved pulleys, and parallel key dimension's formulae. The second part relates to the subjects that the students have studied prior to participating in this integrated learning course, namely Material Selection, Manufacturing Process, Applied Engineering Drawing, CAD (Computer Aided Design) animation software. Moreover, an intensive cooperation between a lecturer and students is another key factor to fulfill the success of integrated learning. Last but not least, the students need to share their knowledge within the group and among the other groups aiming to gain knowledge of and skills in 1) the application of CAD-software to build up manufacture part drawings, 2) assembly drawing, 3) simulation to verify the strength of loaded pulley by method of Finite Element Analysis (FEA), 4) the software to create animation of mounting and dismounting of a pulley to a shaft, and 5) an instruction manual. The end product of this integrated learning, as a result of the above 1 to 5 knowledge and skills obtained, the participating students can create an assembly derived from manufacture part drawings and a video presentation with bilingual (English-Thai) audio description of Vpulley with datum diameter of 250 mm, 4 grooves, and type of groove: SPA.

  16. Status of the IAU Working Group on Cartographic Coordinates and Rotational Elements and Its Upcoming Report

    NASA Astrophysics Data System (ADS)

    Archinal, B. A.

    2015-06-01

    Update on the IAU working group on cartographic coordinates and rotational elements, the services it provides to the planetary community, and the projected changes for and status of its next (“2015”) triennial report.

  17. Method of fabricating vertically aligned group III-V nanowires

    DOEpatents

    Wang, George T; Li, Qiming

    2014-11-25

    A top-down method of fabricating vertically aligned Group III-V micro- and nanowires uses a two-step etch process that adds a selective anisotropic wet etch after an initial plasma etch to remove the dry etch damage while enabling micro/nanowires with straight and smooth faceted sidewalls and controllable diameters independent of pitch. The method enables the fabrication of nanowire lasers, LEDs, and solar cells.

  18. A Group-Theoretical Approach to the Periodic Table of Chemical Elements: Old and New Developments

    E-print Network

    M. R. Kibler

    2005-03-03

    This paper is a companion article to the review paper by the present author devoted to the classification of matter constituents (chemical elements and particles) and published in the first part of the proceedings of The Second Harry Wiener International Memorial Conference (see quant-ph/0310155). It is mainly concerned with a group-theoretical approach to the Periodic Table of the neutral elements based on the noncompact group SO(4,2)xSU(2).

  19. Platinum group elements in the environment: emissions and exposure.

    PubMed

    Dubiella-Jackowska, Aleksandra; Polkowska, Zaneta; Namie?nik, Jacek

    2009-01-01

    PGEs (Pt, Pd, Ru, Ir, and Os) are a relatively new group of anthropogenic pollutants. Specific useful properties of these metals (high resistance to chemical corrosion over a wide range of temperatures, high melting point, high mechanical resistance, and high plasticity) have fomented rapid growth of new and existing applications in various economic and industrial sectors. These metals are not only used in the chemical, petrochemical, electrical, and electronics industries but also PGE use, in various industries, has dramatically increased emissions of these metals to the environment; emissions from vehicle catalytic converters and hospital wastewater discharges are particularly significant. The environmental benefits of using PGEs in vehicle catalytic converters are clear. These metals catalyze the conversion of toxic constituents of exhaust fumes (CO, HCs, NOxs) to water, CO2, and molecular nitrogen. As a result of adverse physico-chemical and mechanical influences on the catalyst surface, PGEs are released from this layer and are emitted into the environment in exhaust fumes. Research results indicate that the levels of such emissions are rather low (ng km(-1)). However, recent data show that certain chemical forms of PGEs emitted from vehicles are, or may be, bioavailable. Hence, the potential for PGEs to bioaccumulate in different environmental compartments should be studied, and, if necessary, addressed. The use of Pt in anticancerous drug preparations also contributes to environmental burdens. Pt, when administered as a drug, is excreted in a patient's urine and, as a consequence, has been observed in hospital and communal wastewater discharges. Few studies have been published that address bioavailability, mode of penetration into live organisms, or environmental fate of PGEs. The toxic effect of these metals on living organisms, including humans, is still in dispute and incompletely elucidated. Contrary to some chlorine complexes of Pt, which most frequently cause allergic reactions, the metallic forms of PGEs are probably inert; however, they may undergo transformation to biologically available forms after release to the environment. Because exposure to PGEs may result in health hazards, it is necessary to evaluate the risks of human exposure to these metals. Available data show that the highest exposed groups (Leceniewska et al. 2001) are individuals who work in refineries, chemical plants, electronics plants, jewelry production, oncological wards (medical personnel), and road maintenance; also highly exposed are women who have silicone breast implants. The effects of PGE exposure in live organisms include the following: asthma, miscarriage, nausea, hair loss, skin diseases, and, in humans, other serious health problems. As production and use of PGEs grow, there is a commensurate need to generate additional experimental and modeling data on them; such data would be designed to provide a better understanding of the environmental disposition and influence on human health of the PGEs. PMID:19110940

  20. On silicon group elements ejected by supernovae type IA

    SciTech Connect

    De, Soma; Timmes, F. X.; Brown, Edward F.; Calder, Alan C.; Townsley, Dean M.; Athanassiadou, Themis; Chamulak, David A.; Hawley, Wendy; Jack, Dennis

    2014-06-01

    There is evidence that the peak brightness of a Type Ia supernova is affected by the electron fraction Y {sub e} at the time of the explosion. The electron fraction is set by the aboriginal composition of the white dwarf and the reactions that occur during the pre-explosive convective burning. To date, determining the makeup of the white dwarf progenitor has relied on indirect proxies, such as the average metallicity of the host stellar population. In this paper, we present analytical calculations supporting the idea that the electron fraction of the progenitor systematically influences the nucleosynthesis of silicon group ejecta in Type Ia supernovae. In particular, we suggest the abundances generated in quasi-nuclear statistical equilibrium are preserved during the subsequent freeze-out. This allows potential recovery of Y {sub e} at explosion from the abundances recovered from an observed spectra. We show that measurement of {sup 28}Si, {sup 32}S, {sup 40}Ca, and {sup 54}Fe abundances can be used to construct Y {sub e} in the silicon-rich regions of the supernovae. If these four abundances are determined exactly, they are sufficient to recover Y {sub e} to 6%. This is because these isotopes dominate the composition of silicon-rich material and iron-rich material in quasi-nuclear statistical equilibrium. Analytical analysis shows the {sup 28}Si abundance is insensitive to Y {sub e}, the {sup 32}S abundance has a nearly linear trend with Y {sub e}, and the {sup 40}Ca abundance has a nearly quadratic trend with Y {sub e}. We verify these trends with post-processing of one-dimensional models and show that these trends are reflected in the model's synthetic spectra.

  1. Finite groups with an automorphism cubing a large fraction of elements

    E-print Network

    Hegarty, Peter

    2007-01-01

    We investigate the possible structures imposed on a finite group by its possession of an automorphism sending a large fraction of the group elements to their cubes, the philosophy being that this should force the group to be, in some sense, close to abelian. We prove two theorems. In the first, we completely classify all finite groups with an automorphism cubing more than half their elements. All such groups are either nilpotent class 2 or have an abelian subgroup of index at most 2. For our second theorem we show that, if a group possesses an automorphism sending more than 4/15 of its elements to their cubes, then it must be solvable. The group A_5 shows that this result is best possible. Both our main findings closely parallel results of previous authors on finite groups possessing an automorphism which inverts many group elements. The technicalities of the new proofs are somewhat more subtle, and also throw up a nice connection to a basic problem in combinatorial number theory, namely the study of subsets ...

  2. Concentrations of platinum group elements in 122 U.S. coal samples

    USGS Publications Warehouse

    Oman, C.L.; Finkelman, R.B.; Tewalt, S.J.

    1997-01-01

    Analysis of more than 13,000 coal samples by semi-quantitative optical emission spectroscopy (OES) indicates that concentrations of the platinum group elements (iridium, palladium, platinum, osmium, rhodium, and ruthenium) are less than 1 ppm in the ash, the limit of detection for this method of analysis. In order to accurately determine the concentration of the platinum group elements (PGE) in coal, additional data were obtained by inductively coupled plasma mass spectroscopy, an analytical method having part-per-billion (ppb) detection limits for these elements. These data indicate that the PGE in coal occur in concentrations on the order of 1 ppb or less.

  3. Sandia Higher Order Elements (SHOE) v 0.5 alpha

    Energy Science and Technology Software Center (ESTSC)

    2013-09-24

    SHOE is research code for characterizing and visualizing higher-order finite elements; it contains a framework for defining classes of interpolation techniques and element shapes; methods for interpolating triangular, quadrilateral, tetrahedral, and hexahedral cells using Lagrange and Legendre polynomial bases of arbitrary order; methods to decompose each element into domains of constant gradient flow (using a polynomial solver to identify critical points); and an isocontouring technique that uses this decomposition to guarantee topological correctness. Please notemore »that this is an alpha release of research software and that some time has passed since it was actively developed; build- and run-time issues likely exist.« less

  4. The Structural Basis for Promoter-35 Element Recognition by the Group IV ? Factors

    SciTech Connect

    Lane,W.; Darst, S.

    2006-01-01

    The control of bacterial transcription initiation depends on a primary s factor for housekeeping functions, as well as alternative s factors that control regulons in response to environmental stresses. The largest and most diverse subgroup of alternative s factors, the group IV extracytoplasmic function s factors, directs the transcription of genes that regulate a wide variety of responses, including envelope stress and pathogenesis. We determined the 2.3- Angstroms resolution crystal structure of the -35 element recognition domain of a group IV s factor, Escherichia coli s{sup E}4, bound to its consensus -35 element, GGAACTT. Despite similar function and secondary structure, the primary and group IV s factors recognize their -35 elements using distinct mechanisms. Conserved sequence elements of the s{sup E} -35 element induce a DNA geometry characteristic of AA/TT-tract DNA, including a rigid, straight double-helical axis and a narrow minor groove. For this reason, the highly conserved AA in the middle of the GGAACTT motif is essential for -35 element recognition by s{sup E}4, despite the absence of direct protein-DNA interactions with these DNA bases. These principles of s{sup E}4/-35 element recognition can be applied to a wide range of other group IV s factors.

  5. Improved Transition Probabilities for Fe-group Elements to Resolve Unexpected Trends in Metal-Poor Stars

    NASA Astrophysics Data System (ADS)

    Wood, Michael P.

    2014-01-01

    Stellar abundances as a function of metallicity provide valuable information regarding the nucleosynthetic history of chemical elements in the Galaxy. Of particular importance are old, metal-poor stars, whose abundances provide a “fossil record” of the nucleosynthetic processes at work in the early Galaxy. The relative abundances of iron (Fe)-group elements provide perhaps the best constraints on the supernova properties of the early generations of stars. Studies of Fe-group abundances in metal-poor stars have found unexpected trends in relative abundance ratios versus metallicity down to metallicities of -4. These results have not been reconciled with current models of Fe-group production in the early Galaxy, and while these trends may indicate a need to revisit these models, the possibility remains that they are manifestations of inaccurate atomic data and/or non-LTE and 3D effects in the photospheres of stars of interest. In order to address these possible explanations, an effort is underway to improve the quality of laboratory atomic transition probabilities for first and second spectra Fe-group lines. A new echelle spectrometer has been developed to complement existing Fourier transform spectrometer (FTS) data typically used in transition probability studies. This instrument is free from the multiplex noise of a FTS which can overwhelm the weak lines necessary for accurate abundance determinations on Fe-group elements. The use of this new spectrometer, combined with an independent calibration method, allows for the reduction of systematic uncertainties, which are often the dominant source of uncertainty for branching fraction measurements. Using this new more accurate laboratory atomic data will allow for searches of non-LTE effects using lines covering a wide range of wavelengths and line strengths. I will discuss the development of this new echelle spectrometer as well as highlight recent results in Ti and Ni, and point toward future work on V and other Fe-group elements. This work is supported by NASA grant NNX10AN93G.

  6. Research paper Os decay system applied to dating platinum-group element

    E-print Network

    Reiners, Peter W.

    Research paper The 190 Pt­186 Os decay system applied to dating platinum-group element MC-ICPMS, as a useful geochronometric tool for direct dating of platinum-group minerals (PGM). It hosts 75% of the world's platinum resources, as well as the majority of the other accessible platinum

  7. On the number of conjugacy classes of ss-elements in a finite group

    E-print Network

    On the number of conjugacy classes of ss-elements in a finite group Burkhard K"ulshammer and Geoffrey R. Robinson Let G be a finite group and ss a set of primes. In this note we will prove two results on the local control of k(G, ss), the number of conjugacy classes of ss

  8. Trace element bioaccumulation in reef fish from New Caledonia: influence of trophic groups and risk assessment for consumers.

    PubMed

    Metian, Marc; Warnau, Michel; Chouvelon, Tiphaine; Pedraza, Fernando; Rodriguez y Baena, Alessia M; Bustamante, Paco

    2013-01-01

    Fourteen trace elements (Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V, and Zn) were analyzed in livers and muscles from 22 fish species from the New Caledonia lagoon, which is subjected to important chemical inputs due to intense land-based mining activities (New Caledonia is the third largest world producer of Ni). The results of this baseline research indicated that livers generally concentrated trace elements to a greater extent than muscles. Nevertheless, the overall trace element concentrations in both tissues were barely above the levels reported in fish and thus contamination at the local scale was poorly discriminated. Although these levels were low, preliminary risk assessment from a global health standpoint suggests that As would be an element potentially leading to exposure of concern for fish consumers. Based on the trace element concentrations in livers and the fish trophic preferences, some trends have been observed among trophic groups: Ag, Cu, Fe, Hg, and Zn concentrations were generally higher in liver of fish with the highest trophic position whereas Cd concentrations were lower in these groups. The use of the leopard coral grouper Plectropomus leopardus as a resident top predator allowed determining the geographical variations in contamination levels with significant differences for six out of the fourteen elements investigated. The sampling sites influenced by anthropogenic inputs were revealed by high Ag, Cd, Cu, Hg, and Pb concentrations. Such geographic differences also applied to Zn but surprisingly not for the typical elements associated with Ni mining, i.e., Co, Cr, Mn and Ni. PMID:23623270

  9. On a group-theoretical approach to the periodic table of chemical elements

    E-print Network

    Maurice Robert Kibler

    2004-08-16

    This paper is concerned with the application of the group SO(4,2)xSU(2) to the periodic table of chemical elements. It is shown how the Madelung rule of the atomic shell model can be used for setting up a periodic table that can be further rationalized via the group SO(4,2)xSU(2) and some of its subgroups. Qualitative results are obtained from the table and the general lines of a programme for a quantitative approach to the properties of chemical elements are developed on the basis of the group SO(4,2)xSU(2).

  10. The Abundances of the Fe Group Elements in Early B Stars in the Magellanic Clouds and Our Galaxy

    NASA Astrophysics Data System (ADS)

    Peters, Geraldine Joan; Adelman, Saul Joseph

    2015-08-01

    The abundances of the Fe-peak elements (Ti, V, Cr, Mn, Fe, Co, and Ni) are of interest as they are important for assessing opacities for stellar evolution calculations, confirming theoretical calculations of explosive nucleosynthesis, and inferring the past history of supernova activity in a galaxy. FUSE FUV spectra of early B stars in the LMC and SMC and HST/STIS FUV/NUV spectra of nearby B stars in our galaxy are analyzed with the Hubeny/Lanz programs TLUSTY/SYNSPEC to determine abundance for the Fe group elements and produce a map of these abundances in the Magellanic Clouds (MC) and Magellanic Bridge (MB). Except for four weak multiplets of Fe III there are no measurable lines from the Fe group in the optical region. The Fe group species found in the FUV spectra of early B stars are primarily in the second stage of ionization. The best set of lines in the FUSE spectral region are Fe III (UV1), V III 1150 Å, and Cr III 1137 Å. Analysis of the galactic B stars provides a good assessment of the reliability of the atomic parameters that are used for the MC calculations. Twenty-two early B stars in the MC and MB and five in our galaxy were analyzed. In general the Fe group abundances range from solar to slightly below solar in our region of the galaxy. But in the MCs the abundances of V, Cr, and Fe tend to be significantly lower than the mean metal abundances for the galaxy. Maps of the Fe group abundances and their variations in the LMC and SMC, tracers of recent enrichment of the ISM from supernova activity, are shown. Support from NASA grants NAG5-13212, NNX10AD66G, STScI HST-GO-13346.22, and USC’s Women in Science and Engineering (WiSE) program is greatly appreciated.

  11. Development of the Hamiltonian and transition moment operators of symmetric top molecules using the O (3) ? C? v ? C3 v group chain

    NASA Astrophysics Data System (ADS)

    El Hilali, A.; Boudon, V.; Loëte, M.

    2005-11-01

    We present a development of the Hamiltonian, dipole moment, and polarizability operators for XY 3Z molecules. These rovibrational operators are written with the aid of a tensorial formalism derived from the one already used in Dijon and adapted to the XY 3Z symmetric tops in a recent paper [A. El Hilali, V. Boudon, M. Loëte, J. Mol. Spectrosc. 234 (2005) 166-174]. We use the O (3) ? C? v ? C3 v group chain. Expressions for the matrix elements are derived for these operators.

  12. Prospects of Direct Determination of |V_tq| CKM Matrix Elements at the LHC

    E-print Network

    Theodota Lagouri

    2012-11-30

    The prospects of measuring the CKM matrix elements |V_tq| with top quarks decays at the LHC are discussed here, with the top quarks produced in the processes pp \\rightarrow ttbarX and pp \\rightarrow t/tbarX, and the subsequent decays t \\rightarrow Ws and/or tbar \\rightarrow Wsbar. As for the direct measurement of |V_tb|, there is also a lot of interest in the direct measurements of |V_ts| and |V_td|, as the absolute values of these CKM matrix elements can be modified by approximately a factor 2 from their SM values. Direct determination of these matrix elements will require a good tagging of the t \\rightarrow s transition (for |V_ts|) and t \\rightarrow d transition (for |V_td|) in the top quark decays, and a very large top quark statistics, which is available at the LHC. Lacking a good tagging for the t \\rightarrow d transition, and also because of the small size of the CKM-matrix element, |V_td| = O(10^-2), direct measurements of |V_ts| at the LHC with main emphasis at the centre of mass energy sqrt(s) of 14 TeV/c^2 based on the PLB paper of Ali et al. [1] are shown. Alternative methods for direct |V_tq| determination at the LHC are also reported.

  13. Levels of platinum group elements and rare-earth elements in wild mushroom species growing in Poland.

    PubMed

    Mleczek, Miros?aw; Niedzielski, Przemys?aw; Kala?, Pavel; Siwulski, Marek; Rzymski, Piotr; G?secka, Monika

    2016-01-01

    Due to limited data-describing abilities of mushrooms to accumulate platinum group elements (PGEs) and rare-earth elements (REEs), the aim of this study was to determine, by inductively coupled plasma optical emission spectrometry followed by microwave-assisted sample digestion by nitric acid, the content of these elements in 20 mushroom species (10 above ground and 10 growing on wood), mostly edible, collected near a busy trunk road. The highest content of PGEs in above-ground mushroom species was observed in Lepista gilva and Suillus bovinus fruit bodies (0.38 ± 0.05 and 0.37 ± 0.03 mg kg(-1) DW, respectively), while in mushrooms growing on wood, the highest content was observed in Pleurotus ostreatus (0.35 ± 0.04 mg kg(-1) DW). The mean content of PGEs for both these groups was 0.23 ± 0.08 and 0.26 ± 0.07 mg kg(-1) DW, respectively. The highest content of REEs in Suillus luteus and Tricholoma equestra was 5.03 ± 0.50 and 2.18 ± 0.56 mg kg(-1) DW, respectively, but within mushrooms growing on wood in Ganoderma applanatum fruiting bodies it was 4.19 ± 0.78 mg kg(-1) DW. Mean contents of REEs were 1.39 ± 1.21 and 1.61 ± 0.97 mg kg(-1) DW in above-ground species and species growing on wood, respectively. Generally, the group of mushroom species growing on wood was capable of slightly higher accumulation of both REEs and PGEs. No limits have been established for both the groups until now. PMID:26515437

  14. The bcr1 DNA Repeat Element Is Specific to the Bacillus cereus Group and Exhibits Mobile Element Characteristics

    PubMed Central

    Økstad, Ole Andreas; Tourasse, Nicolas J.; Stabell, Fredrik B.; Sundfær, Cathrine K.; Egge-Jacobsen, Wolfgang; Risøen, Per Arne; Read, Timothy D.; Kolstø, Anne-Brit

    2004-01-01

    Bacillus cereus strains ATCC 10987 and ATCC 14579 harbor a ?155-bp repeated element, bcr1, which is conserved in B. cereus, B. anthracis, B. thuringiensis, and B. mycoides but not in B. subtilis and B. licheniformis. In this study, we show by Southern blot hybridizations that bcr1 is present in all 54 B. cereus group strains tested but absent in 11 Bacillus strains outside the group, suggesting that bcr1 may be specific and ubiquitous to the B. cereus group. By comparative analysis of the complete genome sequences of B. cereus ATCC 10987, B. cereus ATCC 14579, and B. anthracis Ames, we show that bcr1 is exclusively present in the chromosome but absent from large plasmids carried by these strains and that the numbers of full-length bcr1 repeats for these strains are 79, 54, and 12, respectively. Numerous copies of partial bcr1 elements are also present in the three genomes (91, 128, and 53, respectively). Furthermore, the genomic localization of bcr1 is not conserved between strains with respect to chromosomal position or organization of gene neighbors, as only six full-length bcr1 loci are common to at least two of the three strains. However, the intergenic sequence surrounding a specific bcr1 repeat in one of the three strains is generally strongly conserved in the other two, even in loci where bcr1 is found exclusively in one strain. This finding indicates that bcr1 either has evolved by differential deletion from a very high number of repeats in a common ancestor to the B. cereus group or is moving around the chromosome. The identification of bcr1 repeats interrupting genes in B. cereus ATCC 10987 and ATCC 14579 and the presence of a flanking TTTAT motif in each end show that bcr1 exhibits features characteristic of a mobile element. PMID:15516586

  15. Analysis of the trace element content of coals from the Wabaunsee Group southeastern Nebraska

    SciTech Connect

    Kaplan, S.S.; Carr, J.D.; Kelter, P.B.

    1983-01-01

    Eight coal samples obtained from the Honey Creek, Lorton, Wamego, Elmo, and Nodaway coals of the Wabaunsee Group (Upper Pennsylvanian) were analyzed for their concentration of certain trace elements. Analysis of the data suggests (a) a general decrease of trace element concentrations away from the Precambrian Nemaha Arch in a basinward direction, and (b) the post-diagenetic emplacement of lead, zinc and cadmium typical of mid-continent coals.

  16. sp3-hybridized framework structure of group-14 elements discovered by genetic algorithm

    SciTech Connect

    Nguyen, Manh Cuong; Zhao, Xin; Wang, Cai-Zhuang; Ho, Kai-Ming

    2014-05-01

    Group-14 elements, including C, Si, Ge, and Sn, can form various stable and metastable structures. Finding new metastable structures of group-14 elements with desirable physical properties for new technological applications has attracted a lot of interest. Using a genetic algorithm, we discovered a new low-energy metastable distorted sp3-hybridized framework structure of the group-14 elements. It has P42/mnm symmetry with 12 atoms per unit cell. The void volume of this structure is as large as 139.7Å3 for Si P42/mnm, and it can be used for gas or metal-atom encapsulation. Band-structure calculations show that P42/mnm structures of Si and Ge are semiconducting with energy band gaps close to the optimal values for optoelectronic or photovoltaic applications. With metal-atom encapsulation, the P42/mnm structure would also be a candidate for rattling-mediated superconducting or used as thermoelectric materials.

  17. Conserved Structural Elements in the V3 Crown of HIV-1 gp120

    SciTech Connect

    Jiang, X.; Burke, V; Totrov, M; Williams, C; Cardozo, T; Gorny, M; Zolla-Pazner, S; Kong, X

    2010-01-01

    Binding of the third variable region (V3) of the HIV-1 envelope glycoprotein gp120 to the cell-surface coreceptors CCR5 or CXCR4 during viral entry suggests that there are conserved structural elements in this sequence-variable region. These conserved elements could serve as epitopes to be targeted by a vaccine against HIV-1. Here we perform a systematic structural analysis of representative human anti-V3 monoclonal antibodies in complex with V3 peptides, revealing that the crown of V3 has four conserved structural elements: an arch, a band, a hydrophobic core and the peptide backbone. These are either unaffected by or are subject to minimal sequence variation. As these regions are targeted by cross-clade neutralizing human antibodies, they provide a blueprint for the design of vaccine immunogens that could elicit broadly cross-reactive protective antibodies.

  18. Radiochemical Separation of Group 5 Elements. Model Experiments for Investigation of Dubnium Chemical Behaviour

    SciTech Connect

    Tereshatov, E. E.; Bozhikov, G. A.; Aksenov, N. V.; Starodub, G. Ya.; Vostokin, G. K.; Shishkin, S. V.; Dmitriev, S. N.; Bruchertseifer, H.; Gaeggeler, H. W.

    2007-05-22

    Chemical behaviour of group 5 elements in the aqueous hydrofluoric acid solutions was studied. The radiochemical method for the cation exchange separation of Nb (Pa) and Ta from Zr, Hf and lanthanides is presented. The developed scheme allows excluding of the presence of SF heavy actinides in fractions of separated elements. On the basis of the data of the present work, it is possible to suggest the following order of the stability of the fluoride complexes of group 4 and 5 elements: Nb {approx_equal} Pa > Zr > Hf > Ta. The order of the complex formation is in agreement with theoretical predictions. This analytical procedure can be used in future heavy nuclei synthesis experiments for the separation of dubnium (Db) from other reactions products and for its chemical identification.

  19. IMPORTANCE OF ACTIVATED CARBON'S OXYGEN SURFACE FUNCTIONAL GROUPS ON ELEMENTAL MERCURY ADSORPTION

    EPA Science Inventory

    The effect of varying physical and chemical properties of activated carbons on adsorption of elemental mercury [Hg(0)] was studied by treating two activated carbons to modify their surface functional groups and pore structures. Heat treatment (1200 K) in nitrogen (N2), air oxidat...

  20. Author's personal copy Rheniumosmium isotopes and platinum-group elements in the Rum Layered Suite,

    E-print Network

    Mcdonough, William F.

    , Scotland: Implications for Cr-spinel seam formation and the composition of the Iceland mantle anomaly Brian platinum-group elements Cr-spinel seam formation mantle North Atlantic Igneous Province Iceland The Rum-1 ) Cr-spinel seams at their bases. In order to investigate Cr-spinel seam petro- genesis

  1. New data on platinum group elements in sulfide deposits of the Southern Urals

    NASA Astrophysics Data System (ADS)

    Kovalev, S. G.; Puchkov, V. N.; Salikhov, D. N.

    2015-09-01

    New data on the concentrations of gold and platinum group elements (PGE) in sulfide deposits of the Southern Urals show that a substantial share of Au, Pt, and Pd is concentrated during technological ore processing in their dressing tailings. The behavior of Pt, Pd, and, partly, Au is determined by the size of individual mineral particles.

  2. Research paper The concentration of platinum-group elements and gold in southern African and

    E-print Network

    and Karelian kimberlite-hosted mantle xenoliths: Implications for the noble metal content of the Earth's mantle of the platinum-group elements and gold in 111 mantle xenoliths from more than 20 kimberlite pipes in southern craton on Earth, in part owing to an abundance of mantle xenoliths derived from kimberlites. Study

  3. Conservation of CD44 exon v3 functional elements in mammals

    PubMed Central

    Vela, Elena; Hilari, Josep M; Delclaux, María; Fernández-Bellon, Hugo; Isamat, Marcos

    2008-01-01

    Background The human CD44 gene contains 10 variable exons (v1 to v10) that can be alternatively spliced to generate hundreds of different CD44 protein isoforms. Human CD44 variable exon v3 inclusion in the final mRNA depends on a multisite bipartite splicing enhancer located within the exon itself, which we have recently described, and provides the protein domain responsible for growth factor binding to CD44. Findings We have analyzed the sequence of CD44v3 in 95 mammalian species to report high conservation levels for both its splicing regulatory elements (the 3' splice site and the exonic splicing enhancer), and the functional glycosaminglycan binding site coded by v3. We also report the functional expression of CD44v3 isoforms in peripheral blood cells of different mammalian taxa with both consensus and variant v3 sequences. Conclusion CD44v3 mammalian sequences maintain all functional splicing regulatory elements as well as the GAG binding site with the same relative positions and sequence identity previously described during alternative splicing of human CD44. The sequence within the GAG attachment site, which in turn contains the Y motif of the exonic splicing enhancer, is more conserved relative to the rest of exon. Amplification of CD44v3 sequence from mammalian species but not from birds, fish or reptiles, may lead to classify CD44v3 as an exclusive mammalian gene trait. PMID:18710510

  4. Quality evaluation of value sets from cancer study common data elements using the UMLS semantic groups

    PubMed Central

    Solbrig, Harold R; Chute, Christopher G

    2012-01-01

    Objective The objective of this study is to develop an approach to evaluate the quality of terminological annotations on the value set (ie, enumerated value domain) components of the common data elements (CDEs) in the context of clinical research using both unified medical language system (UMLS) semantic types and groups. Materials and methods The CDEs of the National Cancer Institute (NCI) Cancer Data Standards Repository, the NCI Thesaurus (NCIt) concepts and the UMLS semantic network were integrated using a semantic web-based framework for a SPARQL-enabled evaluation. First, the set of CDE-permissible values with corresponding meanings in external controlled terminologies were isolated. The corresponding value meanings were then evaluated against their NCI- or UMLS-generated semantic network mapping to determine whether all of the meanings fell within the same semantic group. Results Of the enumerated CDEs in the Cancer Data Standards Repository, 3093 (26.2%) had elements drawn from more than one UMLS semantic group. A random sample (n=100) of this set of elements indicated that 17% of them were likely to have been misclassified. Discussion The use of existing semantic web tools can support a high-throughput mechanism for evaluating the quality of large CDE collections. This study demonstrates that the involvement of multiple semantic groups in an enumerated value domain of a CDE is an effective anchor to trigger an auditing point for quality evaluation activities. Conclusion This approach produces a useful quality assurance mechanism for a clinical study CDE repository. PMID:22511016

  5. 33 CFR 155.5052 - Response plan development and evaluation criteria for nontank vessels carrying group V petroleum...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...for nontank vessels carrying group V petroleum oil. 155.5052 Section 155...for nontank vessels carrying group V petroleum oil. Owners or operators of nontank vessels that carry group V petroleum oil as fuel or cargo must meet...

  6. Population Signatures in Planetary Nebulae from Abundances of Fe-group and Neutron-Capture Elements

    NASA Astrophysics Data System (ADS)

    Dinerstein, Harriet L.; Geballe, Thomas R.; Sterling, N. C.

    2015-08-01

    There are two categories of elements for which abundances are measured in planetary nebulae (PNe). The first are species whose abundances may be modified by nuclear reactions in the star prior to PN formation, such as He, C, N, and nuclei made by slow neutron captures (Karakas & Lattanzio 2014, PASA, 31, 30). In contrast, elements unaffected by evolution should indicate the star’s initial composition. These include S, Ar, Cl, and (with certain exceptions) O and Ne, most of which are alpha species. A long-missing piece of the puzzle has been the abundances of the Fe-group elements. We cannot determine a meaningful elemental abundance from the gas-phase Fe lines seen in PNe, since Fe is heavily depleted into dust. Another approach is to use a different element as a proxy for Fe. Dinerstein & Geballe (2001, ApJ, 562, 515) identified a line at 3.625 ?m as due to Zn, the least refractory Fe-group element. Observations of this line in Milky Way PNe yield -1 ? [Zn/H] ? 0 (Smith, Zijlstra, & Dinerstein 2014, MNRAS, 441, 3161; Dinerstein et al. 2015, in preparation). Substituting Zn for Fe, PNe can be placed in the [alpha/Fe] vs. [Fe/H] diagram used to characterize stellar populations. Dividing our sample into probable thin and thick disk members using the kinematic criterion of Peimbert’s Type II and III classes (1978, IAU Symp. 76, 215), we find that they occupy similar regions in [alpha/Fe] vs. [Fe/H] phase space as the stars of those populations. Elevated [alpha/Fe] values at subsolar [Fe/H], which tend to be higher for thick than thin disk PNe, cause degeneracies that make alpha species ambiguous metallicity indicators. This is important for self-enrichment studies, since if the initial abundance of an element is lower than projected from an alpha species, internal synthesis may be required to produce even a solar final abundance. Low observed abundances of the n-capture element Se suggest that many Type III PNe may have subsolar initial abundances of n-capture elements (Sterling, Porter, & Dinerstein 2015, submitted). This work was supported by NSF grants AST-0708429 and 0901432, and JPL contract 1427884.

  7. Minority carrier device comprising a passivating layer including a Group 13 element and a chalcogenide component

    NASA Technical Reports Server (NTRS)

    Barron, Andrew R. (Inventor); Hepp, Aloysius F. (Inventor); Jenkins, Phillip P. (Inventor); MacInnes, Andrew N. (Inventor)

    1999-01-01

    A minority carrier device includes at least one junction of at least two dissimilar materials, at least one of which is a semiconductor, and a passivating layer on at least one surface of the device. The passivating layer includes a Group 13 element and a chalcogenide component. Embodiments of the minority carrier device include, for example, laser diodes, light emitting diodes, heterojunction bipolar transistors, and solar cells.

  8. Measuring the CKM matrix element V{sub tb} at D-zero and CDF

    SciTech Connect

    Heinson, A.P.

    1997-07-01

    I present measurements by the CDF collaboration of the Standard Model three generation CKM matrix element V{sub tb} and of a special case extension with additional assumptions, using current Tevatron t{anti t} data. I then show how we can significantly improve the precision on V{sub tb} and at the same time extend the measurement so it is not constrained by Standard Model assumptions, using single top production at the upgraded Tevatron.

  9. Composition, apparatus, and process, for sorption of gaseous compounds of group II-VII elements

    DOEpatents

    Tom, Glenn M. (New Milford, CT); McManus, James V. (Danbury, CT); Luxon, Bruce A. (Stamford, CT)

    1991-08-06

    Scavenger compositions are disclosed, which have utility for effecting the sorptive removal of hazardous gases containing Group II-VII elements of the Periodic Table, such as are widely encountered in the manufacture of semiconducting materials and semiconductor devices. Gas sorption processes including the contacting of Group II-VII gaseous compounds with such scavenger compositions are likewise disclosed, together with critical space velocity contacting conditions pertaining thereto. Further described are gas contacting apparatus, including mesh structures which may be deployed in gas contacting vessels containing such scavenger compositions, to prevent solids from being introduced to or discharged from the contacting vessel in the gas stream undergoing treatment. A reticulate heat transfer structure also is disclosed, for dampening localized exothermic reaction fronts when gas mixtures comprising Group II-VII constituents are contacted with the scavenger compositions in bulk sorption contacting vessels according to the invention.

  10. Trace elements in organisms of different trophic groups in the White Sea

    NASA Astrophysics Data System (ADS)

    Budko, D. F.; Demina, L. L.; Martynova, D. M.; Gorshkova, O. M.

    2015-09-01

    Concentrations of trace elements (Fe, Mn, Cu, Pb, Ni, Cr, Cd, As, Co, and Se) have been studied in different trophic groups of organisms: primary producers (seston, presented mostly by phytoplankton), primary consumers (mesozooplankton, macrozooplankton, and bivalves), secondary consumers (predatory macrozooplankton and starfish), and consumers of higher trophic levels (fish species), inhabiting the coastal zone of Kandalaksha Bay and the White Sea (Cape Kartesh). The concentrations of elements differ significantly for the size groups of Sagitta elegans (zooplankton) and blue mussel Mytilus edulis, as well as for the bone and muscle tissues of studied fish species, Atlantic cod Gadus morhua marisalbi and Atlantic wolffish Anarhichas lupus. The concentrations of all the studied elements were lower among the primary consumers and producers, but increased again at higher trophic levels, from secondary consumers to tertiary consumers ("mesozooplankton ? macrozooplankton Sagitta elegans" and "mussels ? starfish"). Ni and Pb tended to decline through the food chains seston?…?cod and mesozooplankton?…?stickleback. Only the concentrations of Fe increased in all the trophic chains along with the increase of the trophic level.

  11. Toward Universality in Similarity Renormalization Group Evolved Few-body Potential Matrix Elements

    E-print Network

    Brian Dainton

    2015-02-27

    We first examine how T-matrix equivalence drives the flow of similarity renormalization group (SRG) evolved potential matrix elements to a universal form, with the ultimate goal of gaining insight into universality for three-nucleon forces. In agreement with observations made previously for Lee-Suzuki transformations, regions of universal potential matrix elements are restricted to where half-on-shell T-matrix equivalence holds, but the potentials must also reproduce binding energies. We find universality in local energy regions, reflecting a local decoupling by the SRG. To continue the study in the 3-body sector, we create a simple 1-D spinless boson "theoretical laboratory" for a dramatic improvement in computational efficiency. We introduce a basis-transformation, harmonic oscillator (HO) basis, which is used for current many-body calculations and discuss the imposed truncations. When SRG evolving in a HO-basis, we show that the evolved matrix elements, once transformed back into momentum-representation, differ from those when evolving with momentum representation. This is because the generator in each basis is not exactly the same due to the truncation, which creates evolution artifacts in the 3-body potential matrix elements. In the 2- body sector, this can be avoided by increasing the basis size, but it remains unclear whether this is possible in the 3-body sector, as truncation errors in the 3-body sector are more difficult to avoid, and the computational power required is greatly increased for three-body evolution.

  12. Determination of copper, scandium, molybdenum, tin, lead, and iron group elements in lunar surface materials

    NASA Technical Reports Server (NTRS)

    Pavlenko, L. I.; Simonova, L. V.; Karyakin, A. V.

    1974-01-01

    Distribution regularities of copper, scandium, molybdenum, tin, lead, and iron group elements were investigated in basaltoid rocks of lunar and terrestrial origin. Samples of various regolith zones taken in the area of the Sea of Fertility were analyzed, along with samples of basic and ultrabasic rocks of the East African Rift for their content of the trace admixtures listed. Data obtained on the abundance of copper, scandium, molybdenum, tin, lead, cobalt, nickel, chromium, and vanadium in Luna 16 lunar surface material were compared with the abundance of these elements in samples of lunar rocks returned by Apollo 11, Apollo 12, and Apollo 14, with the exception of scandium; its content in the latter samples was considerably higher.

  13. Precision Measurement of Transition Matrix Elements via Light Shift Cancellation C. D. Herold,* V. D. Vaidya, X. Li, S. L. Rolston, and J. V. Porto

    E-print Network

    Safronova, Marianna

    Precision Measurement of Transition Matrix Elements via Light Shift Cancellation C. D. Herold,* V a method for accurate determination of atomic transition matrix elements at the 10À3 level. Measurements transition matrix elements. The dynamic correc- tion to the BBR shift can also be determined accurately

  14. Multiple complexation of CO and related ligands to a main-group element.

    PubMed

    Braunschweig, Holger; Dewhurst, Rian D; Hupp, Florian; Nutz, Marco; Radacki, Krzysztof; Tate, Christopher W; Vargas, Alfredo; Ye, Qing

    2015-06-18

    The ability of an atom or molecular fragment to bind multiple carbon monoxide (CO) molecules to form multicarbonyl adducts is a fundamental trait of transition metals. Transition-metal carbonyl complexes are vital to industry, appear naturally in the active sites of a number of enzymes (such as hydrogenases), are promising therapeutic agents, and have even been observed in interstellar dust clouds. Despite the wealth of established transition-metal multicarbonyl complexes, no elements outside groups 4 to 12 of the periodic table have yet been shown to react directly with two or more CO units to form stable multicarbonyl adducts. Here we present the synthesis of a borylene dicarbonyl complex, the first multicarbonyl complex of a main-group element prepared using CO. The compound is additionally stable towards ambient air and moisture. The synthetic strategy used--liberation of a borylene ligand from a transition metal using donor ligands--is broadly applicable, leading to a number of unprecedented monovalent boron species with different Lewis basic groups. The similarity of these compounds to conventional transition-metal carbonyl complexes is demonstrated by photolytic liberation of CO and subsequent intramolecular carbon-carbon bond activation. PMID:26085273

  15. Multiple complexation of CO and related ligands to a main-group element

    NASA Astrophysics Data System (ADS)

    Braunschweig, Holger; Dewhurst, Rian D.; Hupp, Florian; Nutz, Marco; Radacki, Krzysztof; Tate, Christopher W.; Vargas, Alfredo; Ye, Qing

    2015-06-01

    The ability of an atom or molecular fragment to bind multiple carbon monoxide (CO) molecules to form multicarbonyl adducts is a fundamental trait of transition metals. Transition-metal carbonyl complexes are vital to industry, appear naturally in the active sites of a number of enzymes (such as hydrogenases), are promising therapeutic agents, and have even been observed in interstellar dust clouds. Despite the wealth of established transition-metal multicarbonyl complexes, no elements outside groups 4 to 12 of the periodic table have yet been shown to react directly with two or more CO units to form stable multicarbonyl adducts. Here we present the synthesis of a borylene dicarbonyl complex, the first multicarbonyl complex of a main-group element prepared using CO. The compound is additionally stable towards ambient air and moisture. The synthetic strategy used--liberation of a borylene ligand from a transition metal using donor ligands--is broadly applicable, leading to a number of unprecedented monovalent boron species with different Lewis basic groups. The similarity of these compounds to conventional transition-metal carbonyl complexes is demonstrated by photolytic liberation of CO and subsequent intramolecular carbon-carbon bond activation.

  16. On the probability that a metacyclic 2-group element fixes a set and its generalized conjugacy class graph

    NASA Astrophysics Data System (ADS)

    Sarmin, N. H.; Omer, S. M. S.; Erfanian, A.

    2015-10-01

    Let G be a metacyclic 2-group. The probability that two random elements commute in G is the quotient of the number of commuting elements by the square of the order of G. This concept has been generalized and extended by several authors. One of these extensions is the probability that an element of a group fixes a set, where the set consists of all subsets of commuting elements of G of size two that are in the form (a,b), where a and b commute and lcm(|a|, |b|) = 2. In this paper, the probability that a group element fixes a set is found for metacyclic 2-groups of negative type of nilpotency class at least two. The results obtained on the size of the orbits are then applied to graph theory, more precisely to generalized conjugacy class graph.

  17. Mono- and polynucleation, atomistic growth, and crystal phase of III-V nanowires under varying group V flow

    NASA Astrophysics Data System (ADS)

    Dubrovskii, V. G.

    2015-05-01

    We present a refined model for the vapor-liquid-solid growth and crystal structure of Au-catalyzed III-V nanowires, which revisits several assumptions used so far and is capable of describing the transition from mononuclear to polynuclear regime and ultimately to regular atomistic growth. We construct the crystal phase diagrams and calculate the wurtzite percentages, elongation rates, critical sizes, and polynucleation thresholds of Au-catalyzed GaAs nanowires depending on the As flow. We find a non-monotonic dependence of the crystal phase on the group V flow, with the zincblende structure being preferred at low and high group V flows and the wurtzite structure forming at intermediate group V flows. This correlates with most of the available experimental data. Finally, we discuss the atomistic growth picture which yields zincblende crystal structure and should be very advantageous for fabrication of ternary III-V nanowires with well-controlled composition and heterointerfaces.

  18. Mono- and polynucleation, atomistic growth, and crystal phase of III-V nanowires under varying group V flow

    SciTech Connect

    Dubrovskii, V. G.

    2015-05-28

    We present a refined model for the vapor-liquid-solid growth and crystal structure of Au-catalyzed III-V nanowires, which revisits several assumptions used so far and is capable of describing the transition from mononuclear to polynuclear regime and ultimately to regular atomistic growth. We construct the crystal phase diagrams and calculate the wurtzite percentages, elongation rates, critical sizes, and polynucleation thresholds of Au-catalyzed GaAs nanowires depending on the As flow. We find a non-monotonic dependence of the crystal phase on the group V flow, with the zincblende structure being preferred at low and high group V flows and the wurtzite structure forming at intermediate group V flows. This correlates with most of the available experimental data. Finally, we discuss the atomistic growth picture which yields zincblende crystal structure and should be very advantageous for fabrication of ternary III-V nanowires with well-controlled composition and heterointerfaces.

  19. A measurement of the cosmic ray elements C to Fe in the two energy intervals 0.5-2.0 GeV/n and 20-60 GeV/n

    NASA Technical Reports Server (NTRS)

    Derrickson, J. H.; Parnell, T. A.; Watts, J. W.; Gregory, J. C.

    1985-01-01

    The study of the cosmic ray abundances beyond 20 GeV/n provides additional information on the propagation and containment of the cosmic rays in the galaxy. Since the average amount of interstellar material traversed by cosmic rays decreases as its energy increases, the source composition undergoes less distortion in this higher energy region. However, data over a wide energy range is necessary to study propagation parameters. Some measurements of some of the primary cosmic ray abundance ratios at both low (near 2 GeV/n) and high (above 20 GeV/n) energy are given and compared to the predictions of the leaky box mode. In particular, the integrated values (above 23.7 GeV/n) for the more abundant cosmic ray elements in the interval C through Fe and the differential flux for carbon, oxygen, and the Ne, Mg, Si group are presented. Limited statistics prevented the inclusion of the odd Z elements.

  20. Prediction of Large-Gap Two-Dimensional Topological Insulators Consisting of Hydrogenated Bilayers of Group III Elements with Bi

    NASA Astrophysics Data System (ADS)

    Crisostomo, Christian P.; Yao, Liang-Zi; Huang, Zhi-Quan; Hsu, Chia-Hsiu; Chuang, Feng-Chuan; Lin, Hsin; Albao, Marvin A.; Bansil, Arun

    2015-03-01

    We use first-principles electronic structure calculations to predict a new class of two-dimensional (2D) topological insulators (TIs) in hydrogenated binary compositions of group III elements (B, Al, Ga, In, and Tl) and bismuth (Bi). We identify band inversions in unhydrogenated pristine GaBi, InBi, and TlBi bilayers, with gaps as large as 556 meV for the TlBi case, making these materials suitable for room-temperature applications. Double-sided hydrogenation in which hydrogen was added on opposite sides also exhibited band inversions in the case of GaBi, InBi, and TlBi just as in the unhydrogenated pristine ones. Furthermore, we report the gap to be 885 meV for the hydrogenated TlBi case. Hydrogenation enhace the band gap without changing the band topology. Moreover, our study also aim to demonstrate the possibility of strain engineering in that the topological phase transition in systems whose phase was nontrivial could be driven by suitable strain. Finally, the effect of placing hydrogen to topological edges was also demonstrated. Our findings suggest that the buckled honeycomb structure is a versatile platform for hosting nontrivial topological states and spin-polarized Dirac fermions with the flexibility of chemical and mechanical tunability. The robustness of III-Bi upon hydrogenation shows that these materials are possible to synthesize by growing on substrates.

  1. Structures, Bonding, and Energetics of Potential Triatomic Circumstellar Molecules Containing Group 15 and 16 Elements.

    PubMed

    Turner, Walter E; Agarwal, Jay; Schaefer, Henry F

    2015-12-01

    The recent discovery of PN in the oxygen-rich shell of the supergiant star VY Canis Majoris points to the formation of several triatomic molecules involving oxygen, nitrogen, and phosphorus; these are also intriguing targets for main-group synthetic inorganic chemistry. In this research, high-level ab initio electronic structure computations were conducted on the potential circumstellar molecule OPN and several of its heavier group 15 and 16 congeners (SPN, SePN, TePN, OPP, OPAs, and OPSb). For each congener, four isomers were examined. Optimized geometries were obtained with coupled cluster theory [CCSD(T)] using large Dunning basis sets [aug-cc-pVQZ, aug-cc-pV(Q+d)Z, and aug-cc-pVQZ-PP], and relative energies were determined at the complete basis set limit of CCSDT(Q) from focal point analyses. The linear phosphorus-centered molecules were consistently the lowest in energy of the group 15 congeners by at least 6 kcal mol(-1), resulting from double-triple and single-double bond resonances within the molecule. The linear nitrogen-centered molecules were consistently the lowest in energy of the group 16 congeners by at least 5 kcal mol(-1), due to the electronegative central nitrogen atom encouraging electron delocalization throughout the molecule. For OPN, OPP, and SPN, anharmonic vibrational frequencies and vibrationally corrected rotational constants are predicted; good agreement with available experimental data is observed. PMID:26566183

  2. CRICKET V2.0 NETWORKS AND MOBILE SYSTEMS GROUP

    E-print Network

    A A PCLK PDATA PALE RADIO DATA SPI_SCK SPI_MOSI SPI_MISO CHP_OUT ADC0 (RSSI) RADIO CONTROL CRICKET V2_MISO CHP_OUT RF_DETECT AVCC AVCC VCC VCC AVCC VCC AVCC VCC VCC VCC J9 HDR 2 X 1 X .1 1 2 1 2 R58 0 OHM C10_OUT L1 L2 CHP_OUT R_BIAS XOSC1 XOSC2 DIO DCLK PCLK PDATA PALE RSSI C18 R13 150K C17 1000pF L5 C19 4.7p

  3. Recent searches for superheavy elements in deep-inelastic reactions. [Approximately 7 MeV/. mu.

    SciTech Connect

    Hulet, E.K.; Lougheed, R.W.; Nitschke, J.M.

    1980-10-01

    New attempts have been made to synthesize superheavy elements (SHE) by nuclear reactions that may possibly form the products at low excitation energies. Survival of the superheavy elements would then be enhanced because of reduced losses from prompt fission. Classical and diffusion-model calculations of deep-inelastic reactions indicate there should be detectable yields of SHE formed with less than 30 MeV of excitation energy. Accordingly, superheavy elements have been sought in such reactions where targets of /sup 248/Cm and /sup 238/U have been irradiated with /sup 136/Xe and /sup 238/U ions. In the most recent experiments, targets of /sup 248/Cm metal (3.5 to 7 mg-cm/sup -2/) were bombarded with 1.8-GeV /sup 238/U ions from the UNILAC accelerator. The longer-lived SHE and actinides near the target Z were chemically separated, and the yields of a number of isotopes of Bk, Cf, Es, and Fm were measured. An upper limit of 30 nb was obtained for the formation of 1-h /sup 259/No. In addition to the off-line chemical recovery and search for SHE, an on-line experiment was performed to detect volatile SHE with half-lives of a minute or more. All experiments to produce and detect superheavy elements were much less than optimum because of premature failures in the Cm-metal targets. The outcome and status of these experiments and the implications of the actinide yields in estimating the chances for forming superheavy elements in the /sup 248/Cm + /sup 238/U reactions are discussed. 5 figures, 1 table.

  4. Reactions of anionic porphyrin with group 11 elements: a spectrophotometric and electrospray ionization mass spectrometry study.

    PubMed

    Giovannetti, Rita; Bartocci, Vito; Pucciarelli, Filippo; Ricciutelli, Massimo

    2004-07-01

    The reaction of 3,8,13,18-tetramethyl-21H,23H-porphine-2,7,12,17-tetrapropionic acid or coproporphyrin-I (CPI) with the elements of 11 group have been studied. CPI is an anionic porphyrin that slowly reacts with copper ion to form Cu(II)CPI and with silver ions to form Ag(II)CPI, Ag(III)CPI complexes and colloidal silver. Gold ions do not form complexes with CPI, but, in the main, colloidal gold and some CPI-N-oxide. The kinetics of the reactions with copper and silver were spectrophotometerically studied and the rate constants were calculated. The identification and characterization of this water-soluble anionic porphyrin and its metal complexes have been performed by electrospray mass spectrometry (ESI-MS) that proved to be an excellent method for these determinations. The multiple charged parent ions for metal free ligand and their metal complexes were identified. PMID:18969510

  5. Platinum-group element geochemistry of zoned ultramafic intrusive suites, Klamath Mountains, California and Oregon.

    USGS Publications Warehouse

    Gray, F.; Page, N.J.; Carlson, C.A.; Wilson, S.A.; Carlson, R.R.

    1986-01-01

    Analyses for platinum-group elements of the varied rock suites of three Alaskan-type ultramafic to mafic multi-intrusive bodies are reported. Ir and Ru are less than analytical sensitivities of 100 and 20 ppb; Rh is less than or near 1 ppb. Average Pd assays vary among the rocks within intrusive complexes and between the three complexes (6.3, 13.7, 36.4 ppb); average Pt assays vary little among the same samples (27.9, 60.9, 34.0 ppb). Statistically adjusted Pt/(Pt + Pd) ratios increase in each suite from gabbro through clinopyroxenite to olivine-rich rocks, possibly owing to Pd fractionation.-G.J.N.

  6. Characterization of the Sukinda and Nausahi ultramafic complexes, Orissa, India by platinum-group element geochemistry

    USGS Publications Warehouse

    Page, N.J.; Banerji, P.K.; Haffty, J.

    1985-01-01

    Samples of 20 chromitite, 14 ultramafic and mafic rock, and 9 laterite and soil samples from the Precambrian Sukinda and Nausahi ultramafic complexes, Orissa, India were analyzed for platinum-group elements (PGE). The maximum concentrations are: palladium, 13 parts per billion (ppb); platinum, 120 ppb; rhodium, 21 ppb; iridium, 210 ppb; and ruthenium, 630 ppb. Comparison of chondrite-normalized ratios of PGE for the chromitite samples of lower Proterozoic to Archean age with similar data from Paleozoic and Mesozoic ophiolite complexes strongly implies that these complexes represent Precambrian analogs of ophiolite complexes. This finding is consistent with the geology and petrology of the Indian complexes and suggests that plate-tectonic and ocean basin developement models probably apply to some parts of Precambrian shield areas. ?? 1985.

  7. Improved and Expanded Near-IR Oscillator Strengths for Fe-group Elements

    NASA Astrophysics Data System (ADS)

    Wood, Michael; Nave, Gillian; Sneden, Christopher Alan

    2015-08-01

    The use of modern experimental techniques, including LIF lifetime and FTS branching fraction measurements, has significantly increased the scope and reliability of laboratory atomic transition probabilities in the UV and visible. However, this combination of techniques is problematic in the IR, a region of increasing importance due to improved detector, spectrometer, and telescope technologies. The result is a significant gap between the capabilities to record new IR astronomical spectra and the data needed to sufficiently analyze them. To aid in closing this gap, we are incorporating new techniques, including reverse stellar analyses, to measure sets of oscillator strengths in the near-IR (? ? 1-5 ?m), with a primary focus on the Fe-group elements. A description of the methods and their applicability will be presented, including recent results for Ti I.

  8. Leaves of Phragmites australis as potential atmospheric biomonitors of Platinum Group Elements.

    PubMed

    Bonanno, Giuseppe; Pavone, Pietro

    2015-04-01

    The increasing emissions of Platinum Group Elements (PGEs), namely Pt, Pd and Rh, may pose a significant risk to ecosystem processes and human health. A periodic assessment of PGEs distribution in the environment is thus of the utmost importance for the implementation of timely measures of mitigation. Although several studies have quantified PGEs in different life forms such as mammals, birds, fish, crustaceans, algae, mosses and even human beings, data about vascular plants need further surveys. This study aimed to test the suitability of the grass Phragmites australis (common reed) as a biomonitor of PGEs atmospheric pollution. The results showed that Pd and Pt concentrations in leaves are significantly higher in urban areas. In particular, Pd showed the highest range of values in line with current studies that consider palladium as the main element of traffic-related pollution. Overall, the leaves of Phragmites australis reflected the different gradient of PGEs emissions, and may thus be considered as potential biomonitors of atmospheric pollution. PMID:25596354

  9. Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements: 2009

    NASA Astrophysics Data System (ADS)

    Archinal, B. A.; A'Hearn, M. F.; Bowell, E.; Conrad, A.; Consolmagno, G. J.; Courtin, R.; Fukushima, T.; Hestroffer, D.; Hilton, J. L.; Krasinsky, G. A.; Neumann, G.; Oberst, J.; Seidelmann, P. K.; Stooke, P.; Tholen, D. J.; Thomas, P. C.; Williams, I. P.

    2011-02-01

    Every three years the IAU Working Group on Cartographic Coordinates and Rotational Elements revises tables giving the directions of the poles of rotation and the prime meridians of the planets, satellites, minor planets, and comets. This report takes into account the IAU Working Group for Planetary System Nomenclature (WGPSN) and the IAU Committee on Small Body Nomenclature (CSBN) definition of dwarf planets, introduces improved values for the pole and rotation rate of Mercury, returns the rotation rate of Jupiter to a previous value, introduces improved values for the rotation of five satellites of Saturn, and adds the equatorial radius of the Sun for comparison. It also adds or updates size and shape information for the Earth, Mars' satellites Deimos and Phobos, the four Galilean satellites of Jupiter, and 22 satellites of Saturn. Pole, rotation, and size information has been added for the asteroids (21) Lutetia, (511) Davida, and (2867) Šteins. Pole and rotation information has been added for (2) Pallas and (21) Lutetia. Pole and rotation and mean radius information has been added for (1) Ceres. Pole information has been updated for (4) Vesta. The high precision realization for the pole and rotation rate of the Moon is updated. Alternative orientation models for Mars, Jupiter, and Saturn are noted. The Working Group also reaffirms that once an observable feature at a defined longitude is chosen, a longitude definition origin should not change except under unusual circumstances. It is also noted that alternative coordinate systems may exist for various (e.g. dynamical) purposes, but specific cartographic coordinate system information continues to be recommended for each body. The Working Group elaborates on its purpose, and also announces its plans to occasionally provide limited updates to its recommendations via its website, in order to address community needs for some updates more often than every 3 years. Brief recommendations are also made to the general planetary community regarding the need for controlled products, and improved or consensus rotation models for Mars, Jupiter, and Saturn.

  10. Report of the IAU Working Group on cartographic coordinates and rotational elements: 2009

    USGS Publications Warehouse

    Archinal, B.A.; A'Hearn, M.F.; Bowell, E.; Conrad, A.; Consolmagno, G.J.; Courtin, R.; Fukushima, T.; Hestroffer, D.; Hilton, J.L.; Krasinsky, G.A.; Neumann, G.; Oberst, J.; Seidelmann, P.K.; Stooke, P.; Tholen, D.J.; Thomas, P.C.; Williams, I.P.

    2010-01-01

    Every three years the IAU Working Group on Cartographic Coordinates and Rotational Elements revises tables giving the directions of the poles of rotation and the prime meridians of the planets, satellites, minor planets, and comets. This report takes into account the IAU Working Group for Planetary System Nomenclature (WGPSN) and the IAU Committee on Small Body Nomenclature (CSBN) definition of dwarf planets, introduces improved values for the pole and rotation rate of Mercury, returns the rotation rate of Jupiter to a previous value, introduces improved values for the rotation of five satellites of Saturn, and adds the equatorial radius of the Sun for comparison. It also adds or updates size and shape information for the Earth, Mars’ satellites Deimos and Phobos, the four Galilean satellites of Jupiter, and 22 satellites of Saturn. Pole, rotation, and size information has been added for the asteroids (21) Lutetia, (511) Davida, and (2867) Šteins. Pole and rotation information has been added for (2) Pallas and (21) Lutetia. Pole and rotation and mean radius information has been added for (1) Ceres. Pole information has been updated for (4) Vesta. The high precision realization for the pole and rotation rate of the Moon is updated. Alternative orientation models for Mars, Jupiter, and Saturn are noted. The Working Group also reaffirms that once an observable feature at a defined longitude is chosen, a longitude definition origin should not change except under unusual circumstances. It is also noted that alternative coordinate systems may exist for various (e.g. dynamical) purposes, but specific cartographic coordinate system information continues to be recommended for each body. The Working Group elaborates on its purpose, and also announces its plans to occasionally provide limited updates to its recommendations via its website, in order to address community needs for some updates more often than every 3 years. Brief recommendations are also made to the general planetary community regarding the need for controlled products, and improved or consensus rotation models for Mars, Jupiter, and Saturn.

  11. Report of the IAU Working Group on cartographic coordinates and rotational elements: 2009

    USGS Publications Warehouse

    Archinal, Brent A.; A’Hearn, Michael F.; Bowell, Edward; Conrad, Al; Consolmagno, Guy J.; Courtin, Regis; Fukushima, Toshio; Hestroffer, Daniel; Hilton, James L.; Krasinsky, Georgij A.; Neumann, Gregory; Oberst, Jurgen; Seidelmann, P. Kenneth; Stooke, Philip; Tholen, David J.; Thomas, Peter C.; Williams, Iwan P.

    2010-01-01

    Every three years the IAU Working Group on Cartographic Coordinates and Rotational Elements revises tables giving the directions of the poles of rotation and the prime meridians of the planets, satellites, minor planets, and comets. This report takes into account the IAU Working Group for Planetary System Nomenclature (WGPSN) and the IAU Committee on Small Body Nomenclature (CSBN) definition of dwarf planets, introduces improved values for the pole and rotation rate of Mercury, returns the rotation rate of Jupiter to a previous value, introduces improved values for the rotation of five satellites of Saturn, and adds the equatorial radius of the Sun for comparison. It also adds or updates size and shape information for the Earth, Mars’ satellites Deimos and Phobos, the four Galilean satellites of Jupiter, and 22 satellites of Saturn. Pole, rotation, and size information has been added for the asteroids (21) Lutetia, (511) Davida, and (2867) Šteins. Pole and rotation information has been added for (2) Pallas and (21) Lutetia. Pole and rotation and mean radius information has been added for (1) Ceres. Pole information has been updated for (4) Vesta. The high precision realization for the pole and rotation rate of the Moon is updated. Alternative orientation models for Mars, Jupiter, and Saturn are noted. The Working Group also reaffirms that once an observable feature at a defined longitude is chosen, a longitude definition origin should not change except under unusual circumstances. It is also noted that alternative coordinate systems may exist for various (e.g. dynamical) purposes, but specific cartographic coordinate system information continues to be recommended for each body. The Working Group elaborates on its purpose, and also announces its plans to occasionally provide limited updates to its recommendations via its website, in order to address community needs for some updates more often than every 3 years. Brief recommendations are also made to the general planetary community regarding the need for controlled products, and improved or consensus rotation models for Mars, Jupiter, and Saturn.

  12. Platinum group elements in automobile catalysts: characterization, sources and environmental mobility

    NASA Astrophysics Data System (ADS)

    Mihaljevic, Martin; Ettler, Vojtech; Strnad, Ladislav; Sebek, Ondrej; Stedry, Robin; Adamec, Vladimir

    2010-05-01

    The platinum group elements (PGE) comprise Ru, Rh, Pd, Os, Ir, and Pt. The PGE are extremely siderophile and most of the elements were during the Earth differentiation partitioned into the core. The average natural concentration of PGE in Earth's crust is low and range of 0.X - X0 ?g kg-1. During the magmatic process the PGE are strongly partitioned into sulphides and Ni minerals. The distribution of PGE and increase of their emissions in the environment are mostly related to the use of automobile catalyst (AC) in car engines (in USA since 1975, in Europe since 1986). The ACs consist of a honeycomb support (made from ?-Al2O3 or cordierite with trace element admixtures - mostly lanthanides and Zr) coated with Pt, Pd and Rh in different ratios. While AC for gasoline engines contain a mixture of Pt-Pd-Rh or Pd-Rh, AC for diesel engines are composed only of Pt. New and aged AC of gasoline and diesel engines, AC standard reference materials, tunnel dust from Prague and tunnel dust reference materials were studied using scanning electron microscopy, electron microanalyses, X-ray diffraction and chemical analyses using inductively coupled plasma mass spectrometry. The studied ACs differ in phase and elemental composition and PGE contents. The matrix of the gasoline AC is composed of Al, Zr, Ce, Ba oxides with Rh, Pd and Pt coatings. The support of diesel AC is composed of Mg, Al, Fe, Ti and Ca silicates with Pt coatings. Aged gasoline AC exhibit higher Mg, Mn, Zn and Pb contents compared to the new AC. Aged diesel AC differs in higher Zn and Ba contents compared to the new one. Both aged and new AC does not differ in total PGE contents. Leaching experiments were done with AC, real samples of tunnel dusts and reference materials with inorganic (Cl-, HPO42-) and organic (low and high molecular weight) complexing solutions. The solubility experiments indicate that PGE mobilization from ACs is dependent on particle type, time and complexing medium.

  13. Impact Behavior of A356 Foundry Alloys in the Presence of Trace Elements Ni and V

    NASA Astrophysics Data System (ADS)

    Casari, Daniele; Ludwig, Thomas H.; Merlin, Mattia; Arnberg, Lars; Garagnani, Gian Luca

    2015-02-01

    In the present work, the impact behavior of unmodified A356 alloys with the addition of Ni or V in as-cast and T6 heat-treated conditions was assessed. Charpy V-notched specimens obtained from sand and permanent mold casting showed low total absorbed energy average values ( W t < 2 J). SEM analysis of fracture profiles and surfaces indicated a Si-driven crack propagation with a predominant transgranular fracture mode. Occasionally, intergranular contributions to fracture were detected in the permanent mold cast alloys due to the locally finer microstructure. Concurrent mechanisms related to the chemical composition, solidification conditions and heat treatment were found to control the impact properties of the alloys. While the trace element Ni exerted only minor effects on the impact toughness of the A356 alloy, V had a strong influence: (i) V-containing sand cast alloys absorbed slightly higher impact energies compared to the corresponding A356 base alloys; (ii) in the permanent mold cast alloys, V in solid solution led to a considerable loss of ductility, which in turn decreased the total absorbed energy.

  14. Implementation of Hybrid V-Cycle Multilevel Methods for Mixed Finite Element Systems with Penalty

    NASA Technical Reports Server (NTRS)

    Lai, Chen-Yao G.

    1996-01-01

    The goal of this paper is the implementation of hybrid V-cycle hierarchical multilevel methods for the indefinite discrete systems which arise when a mixed finite element approximation is used to solve elliptic boundary value problems. By introducing a penalty parameter, the perturbed indefinite system can be reduced to a symmetric positive definite system containing the small penalty parameter for the velocity unknown alone. We stabilize the hierarchical spatial decomposition approach proposed by Cai, Goldstein, and Pasciak for the reduced system. We demonstrate that the relative condition number of the preconditioner is bounded uniformly with respect to the penalty parameter, the number of levels and possible jumps of the coefficients as long as they occur only across the edges of the coarsest elements.

  15. Trans-silencing by P elements inserted in subtelomeric heterochromatin involves the Drosophila Polycomb group gene, Enhancer of zeste.

    PubMed Central

    Roche, S E; Rio, D C

    1998-01-01

    Drosophila P-element transposition is regulated by a maternally inherited state known as P cytotype. An important aspect of P cytotype is transcriptional repression of the P-element promoter. P cytotype can also repress non-P-element promoters within P-element ends, suggesting that P cytotype repression might involve chromatin-based transcriptional silencing. To learn more about the role of chromatin in P cytotype repression, we have been studying the P strain Lk-P(1A). This strain contains two full-length P elements inserted in the heterochromatic telomere-associated sequences (TAS elements) at cytological location 1A. Mutations in the Polycomb group gene (Pc-G gene), Enhancer of zeste (E(z)), whose protein product binds at 1A, resulted in a loss of Lk-P(1A) cytotype control. E(z) mutations also affected the trans-silencing of heterologous promoters between P-element termini by P-element transgenes inserted in the TAS repeats. These data suggest that pairing interactions between P elements, resulting in exchange of chromatin structures, may be a mechanism for controlling the expression and activity of P elements. PMID:9691041

  16. Elemental copper nanoparticle toxicity to different trophic groups involved in anaerobic and anoxic wastewater treatment processes.

    PubMed

    Gonzalez-Estrella, Jorge; Puyol, Daniel; Gallagher, Sara; Sierra-Alvarez, Reyes; Field, Jim A

    2015-04-15

    Elemental copper nanoparticles (Cu(0) NPs) are potentially inhibitory to the different key microbial trophic groups involved in biological wastewater treatment processes. Cu-based NPs are known to be toxic to methanogens at low concentrations. However, very little is known about the toxic effect of Cu(0) NPs on other microbial groups involved in either upper trophic levels of anaerobic digestion or anoxic nitrogen removal processes. This study evaluated the toxicity of Cu(0) NPs to glucose fermentation, syntrophic propionate oxidation and denitrification in shaken batch bioassays with soluble substrates. Batch experiments were also supplemented with CuCl2 to evaluate the inhibitory impact of soluble Cu(II) ions. Syntrophic propionate oxidation and glucose fermentation were the least and most inhibited processes with inhibition constant (Ki) values of 0.202 and 0.047 mM of added Cu(0) NPs, respectively. Further analyses revealed that the Ki values calculated as a function of the free soluble Cu concentration were <0.003 mM for every biological process tested and most of these Ki values were similar in order of magnitude regardless of whether the Cu source was CuCl2 or Cu(0) NPs. The results taken as a whole indicate that Cu(0) NPs are toxic to all the microbial processes studied. Therefore, Cu(0) NPs can potentially be an important inhibitor of anaerobic wastewater treatment processes that rely on these trophic groups. The evidence suggests that the inhibitory impact of Cu(0) NPs was mainly due to the release of toxic Cu(II) ions originating from the corrosion and dissolution of Cu(0) NPs. PMID:25634735

  17. Re-187-Os-187, Pt-190-Os-186 Isotopic and Highly Siderophile Element Systematics of Group IVA Irons

    NASA Technical Reports Server (NTRS)

    Walker, R. J.; McCoy, T. J.; Schulte, R. F.; McDonough, W. F.; Ash, R. D.

    2005-01-01

    We have recently completed Re-187-Os-187 and Pt-190-Os-186 isotopic and elemental studies of the two largest magmatic iron meteorite groups, IIAB and IIIAB [1]. These studies revealed closed-system behavior of both isotopic systems, but complex trace element behavior for Re, Pt and Os in group IIIAB. Here we examine isotopic and trace elemental systematics of group IVA irons. The IVA irons are not as extensively fractionated as IIAB and IIIAB and their apparently less complex crystallization history may make for more robust interpretation of the relative partitioning behavior of Re, Pt and Os, as well as the other highly siderophile elements (HSE) measured here; Pd, Ru and Ir [e.g. 2]. An additional goal of our continuing research plan for iron meteorites is to assess the possibility of relating certain ungrouped irons with major groups via trace element modeling. Here, the isotopic and trace element systematics of the ungrouped irons Nedagolla and EET 83230 are compared with the IVA irons.

  18. 33 CFR 155.5052 - Response plan development and evaluation criteria for nontank vessels carrying group V petroleum...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... requirements of 33 CFR 155.1052. ... evaluation criteria for nontank vessels carrying group V petroleum oil. 155.5052 Section 155.5052 Navigation... Response plan development and evaluation criteria for nontank vessels carrying group V petroleum...

  19. Contribution of Exogenous Genetic Elements to the Group A Streptococcus Metagenome

    PubMed Central

    Beres, Stephen B.; Musser, James M.

    2007-01-01

    Variation in gene content among strains of a bacterial species contributes to biomedically relevant differences in phenotypes such as virulence and antimicrobial resistance. Group A Streptococcus (GAS) causes a diverse array of human infections and sequelae, and exhibits a complex pathogenic behavior. To enhance our understanding of genotype-phenotype relationships in this important pathogen, we determined the complete genome sequences of four GAS strains expressing M protein serotypes (M2, M4, and 2 M12) that commonly cause noninvasive and invasive infections. These sequences were compared with eight previously determined GAS genomes and regions of variably present gene content were assessed. Consistent with the previously determined genomes, each of the new genomes is ?1.9 Mb in size, with ?10% of the gene content of each encoded on variably present exogenous genetic elements. Like the other GAS genomes, these four genomes are polylysogenic and prophage encode the majority of the variably present gene content of each. In contrast to most of the previously determined genomes, multiple exogenous integrated conjugative elements (ICEs) with characteristics of conjugative transposons and plasmids are present in these new genomes. Cumulatively, 242 new GAS metagenome genes were identified that were not present in the previously sequenced genomes. Importantly, ICEs accounted for 41% of the new GAS metagenome gene content identified in these four genomes. Two large ICEs, designated 2096-RD.2 (63 kb) and 10750-RD.2 (49 kb), have multiple genes encoding resistance to antimicrobial agents, including tetracycline and erythromycin, respectively. Also resident on these ICEs are three genes encoding inferred extracellular proteins of unknown function, including a predicted cell surface protein that is only present in the genome of the serotype M12 strain cultured from a patient with acute poststreptococcal glomerulonephritis. The data provide new information about the GAS metagenome and will assist studies of pathogenesis, antimicrobial resistance, and population genomics. PMID:17726530

  20. On-line gas phase chromatography of the bromides of the group 4, 5, and 6 elements

    SciTech Connect

    Sylwester, E.R.; Gregorich, K.E.; Lee, D.M.; Chung, Y.H.

    1997-12-31

    Gas phase chromatography has been used to determine the volatility of bromides of the group 4, 5, and 6 elements, including the transactinides 104 (Rf) and 105 (Ha). The Heavy Element Volatility Instrument (HEVI) was used to measure the volatilities of the bromides of short-lived isotopes of these elements. Adsorption enthalpy values were calculated from the observed volatilities using a Monte Carlo program. The values for RfBr{sub 4} and HaBr{sub 5} are similar to ZrBr{sub 4} and NbBr{sub 5} rather than to HfBr{sub 4} and TaBr{sub 5}. This deviates from a simple extrapolation from periodic table trends and may indicate the influence of relativistic effects on the electronic level structure of these transactinides. The group 6 element Seaborgium (Sg) has not yet been studied due to the low production cross-section.

  1. Mineralogical siting of platinum-group elements in pentlandite from the Bushveld Complex, South Africa

    NASA Astrophysics Data System (ADS)

    Junge, Malte; Wirth, Richard; Oberthür, Thomas; Melcher, Frank; Schreiber, Anja

    2015-01-01

    The Bushveld Complex in South Africa hosts the world's largest resources of platinum-group elements (PGEs), which are mainly mined from three ore bodies, namely the Merensky Reef, the UG-2 chromitite, and the Platreef. In these ores, the PGEs are bimodally distributed, occurring both as discrete platinum-group minerals (PGMs) and hosted by sulfides. The presence of PGEs in sulfides has been demonstrated by electron probe microanalysis, laser ablation induced coupled plasma mass spectrometry, secondary ion mass spectrometry, and particle-induced X-ray emission. However, evidence is lacking on the mineralogical siting of the PGEs, e.g., whether they occur in solid solution, as nano-inclusions, and/or micro-inclusions. Therefore, in the present study, a combination of focused ion beam and transmission electron microscopy was used which allows to obtain crystal structural relationships between the host mineral and incorporated trace elements and revealing the physicochemical state of the PGE in sulfides. The present study confirms the existence of micrometer-sized discrete PGMs in the ores. Further, the PGEs occur in a number of forms, namely (1) as discrete nano-inclusions of PGMs, (2) as patchily distributed solid solution, (3) ordered within the pentlandite crystal structure, substituting for Ni and/or Fe (superlattice), and (4) as homogenous solid solution. Nanometer-sized PGMs (nPGMs) show no orientation relationship with the host sulfide mineral. Consequently, they are discrete phases, which were trapped within pentlandite during sulfide growth. Heterogeneous and patchy distributions of Rh and Ir within the pentlandite lattice suggest that Rh and Ir were already present within the sulfide liquid. The absence of possible reaction partners (e.g., Bi, As, and Sn) necessary for the formation of discrete PGMs forced Rh and Ir to remain in the crystal lattice of pentlandite and down-temperature exsolution caused patchy distribution patterns of Rh and Ir. High concentrations of Rh and Ir in pentlandite initiate ordering of the randomly distributed PGE in form of nanometer-sized lamellae resulting in the formation of a superlattice. Palladium is homogenously distributed within the pentlandite lattice, even at high Pd concentrations, and in addition also occurs as nPGMs.

  2. 33 CFR 155.1052 - Response plan development and evaluation criteria for vessels carrying group V petroleum oil as a...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... evaluation criteria for vessels carrying group V petroleum oil as a primary cargo. 155.1052 Section 155.1052....1052 Response plan development and evaluation criteria for vessels carrying group V petroleum oil as a primary cargo. (a) Owners and operators of vessels that carry group V petroleum oil as a primary...

  3. 33 CFR 155.1052 - Response plan development and evaluation criteria for vessels carrying group V petroleum oil as a...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... evaluation criteria for vessels carrying group V petroleum oil as a primary cargo. 155.1052 Section 155.1052....1052 Response plan development and evaluation criteria for vessels carrying group V petroleum oil as a primary cargo. (a) Owners and operators of vessels that carry group V petroleum oil as a primary...

  4. 33 CFR 155.1052 - Response plan development and evaluation criteria for vessels carrying group V petroleum oil as a...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... evaluation criteria for vessels carrying group V petroleum oil as a primary cargo. 155.1052 Section 155.1052....1052 Response plan development and evaluation criteria for vessels carrying group V petroleum oil as a primary cargo. (a) Owners and operators of vessels that carry group V petroleum oil as a primary...

  5. 33 CFR 155.1052 - Response plan development and evaluation criteria for vessels carrying group V petroleum oil as a...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... evaluation criteria for vessels carrying group V petroleum oil as a primary cargo. 155.1052 Section 155.1052....1052 Response plan development and evaluation criteria for vessels carrying group V petroleum oil as a primary cargo. (a) Owners and operators of vessels that carry group V petroleum oil as a primary...

  6. 33 CFR 155.1052 - Response plan development and evaluation criteria for vessels carrying group V petroleum oil as a...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... evaluation criteria for vessels carrying group V petroleum oil as a primary cargo. 155.1052 Section 155.1052....1052 Response plan development and evaluation criteria for vessels carrying group V petroleum oil as a primary cargo. (a) Owners and operators of vessels that carry group V petroleum oil as a primary...

  7. 33 CFR 155.1052 - Response plan development and evaluation criteria for vessels carrying group V petroleum oil as a...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...criteria for vessels carrying group V petroleum oil as a primary cargo. 155.1052...criteria for vessels carrying group V petroleum oil as a primary cargo. (a) Owners...operators of vessels that carry group V petroleum oil as a primary cargo must provide...

  8. 33 CFR 155.1052 - Response plan development and evaluation criteria for vessels carrying group V petroleum oil as a...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...criteria for vessels carrying group V petroleum oil as a primary cargo. 155.1052...criteria for vessels carrying group V petroleum oil as a primary cargo. (a) Owners...operators of vessels that carry group V petroleum oil as a primary cargo must provide...

  9. 33 CFR 155.1052 - Response plan development and evaluation criteria for vessels carrying group V petroleum oil as a...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...criteria for vessels carrying group V petroleum oil as a primary cargo. 155.1052...criteria for vessels carrying group V petroleum oil as a primary cargo. (a) Owners...operators of vessels that carry group V petroleum oil as a primary cargo must provide...

  10. 33 CFR 155.1052 - Response plan development and evaluation criteria for vessels carrying group V petroleum oil as a...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...criteria for vessels carrying group V petroleum oil as a primary cargo. 155.1052...criteria for vessels carrying group V petroleum oil as a primary cargo. (a) Owners...operators of vessels that carry group V petroleum oil as a primary cargo must provide...

  11. 33 CFR 155.1052 - Response plan development and evaluation criteria for vessels carrying group V petroleum oil as a...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...criteria for vessels carrying group V petroleum oil as a primary cargo. 155.1052...criteria for vessels carrying group V petroleum oil as a primary cargo. (a) Owners...operators of vessels that carry group V petroleum oil as a primary cargo must provide...

  12. Vertical group III-V nanowires on si, heterostructures, flexible arrays and fabrication

    DOEpatents

    Wang, Deli; Soci, Cesare; Bao, Xinyu; Wei, Wei; Jing, Yi; Sun, Ke

    2015-01-13

    Embodiments of the invention provide a method for direct heteroepitaxial growth of vertical III-V semiconductor nanowires on a silicon substrate. The silicon substrate is etched to substantially completely remove native oxide. It is promptly placed in a reaction chamber. The substrate is heated and maintained at a growth temperature. Group III-V precursors are flowed for a growth time. Preferred embodiment vertical Group III-V nanowires on silicon have a core-shell structure, which provides a radial homojunction or heterojunction. A doped nanowire core is surrounded by a shell with complementary doping. Such can provide high optical absorption due to the long optical path in the axial direction of the vertical nanowires, while reducing considerably the distance over which carriers must diffuse before being collected in the radial direction. Alloy composition can also be varied. Radial and axial homojunctions and heterojunctions can be realized. Embodiments provide for flexible Group III-V nanowire structures. An array of Group III-V nanowire structures is embedded in polymer. A fabrication method forms the vertical nanowires on a substrate, e.g., a silicon substrate. Preferably, the nanowires are formed by the preferred methods for fabrication of Group III-V nanowires on silicon. Devices can be formed with core/shell and core/multi-shell nanowires and the devices are released from the substrate upon which the nanowires were formed to create a flexible structure that includes an array of vertical nanowires embedded in polymer.

  13. Smoothed particle hydrodynamics and element bending group modeling of flexible fibers interacting with viscous fluids.

    PubMed

    Yang, Xiufeng; Liu, Moubin; Peng, Shiliu

    2014-12-01

    This paper presents a smoothed particle hydrodynamics (SPH) and element bending group (EBG) coupling method for modeling the interaction of flexible fibers with moving viscous fluids. SPH is a well-developed mesh-free particle method for simulating viscous fluid flows. EBG is also a particle method for modeling flexible bodies. The interaction of flexible fibers with moving viscous fluids is rendered through the interaction of EBG particles for flexible fiber and SPH particles for fluid. In numerical simulation, flexible fibers of different lengths are immersed in a moving viscous fluid driven by a body force. The drag force on the fiber obtained from SPH-EBG simulation agrees well with experimental observations. It is shown that the flexible fiber demonstrates three typical bending modes, including the U-shaped mode, the flapping mode, and the closed mode, and that the flexible fiber experiences a drag reduction due to its reconfiguration by bending. It is also found that the U4/3 drag scaling law for a flexible fiber is only valid for the U-shaped mode, but not valid for the flapping and closed modes. The results indicate that the reconfiguration of a flexible fiber is caused by the fluid force acting on it, while vortex shedding is of importance in the translations of bending modes. PMID:25615191

  14. Platinum-group element concentrations in BCR-723: a quantitative review of published analyses.

    PubMed

    Sutherland, Ross A

    2007-01-23

    BCR-723 is the only environmental certified reference material for platinum-group elements (PGEs) Pt, Pd and Rh. It has been an integral component of quality control/quality assurance procedures in environmental laboratories measuring PGEs, since 2001. Here, we present an extensive quantitative review of the published PGEs measured in BCR-723, since its introduction. A statistical examination of concentrations, measurement precision and accuracy for 25 studies is presented. Measurement typically starts with an aqua regia digestion, followed by some form of pre-concentration or separation procedure, and quantitation by ICP-MS. Use of a sample mass below the recommended value of 100 mg has been shown to produce biased results for acid-based digestions or with laser ablation. Platinum is the most precisely and accurately measured PGE in BCR-723, followed by Rh, and finally by Pd. Literature precision data for all autocatalyst PGEs did not differ significantly (alpha=0.05) from those obtained by the original laboratories used to certify BCR-723. Measurement accuracies for the literature tabulated PGE data did not differ significantly from zero, indicating an overall lack of directional bias. These results should be encouraging to the analytical community, but further advancements, especially for Pd quantification are required. PMID:17386493

  15. High salinity volatile phases in magmatic Ni-Cu-platinum group element deposits

    NASA Astrophysics Data System (ADS)

    Hanley, J. J.; Mungall, J. E.

    2004-12-01

    The role of "deuteric" fluids (exsolved magmatic volatile phases) in the development of Ni-Cu-PGE (platinum group element) deposits in mafic-ultramafic igneous systems is poorly understood. Although considerable field evidence demonstrates unambiguously that fluids modified most large primary Ni-Cu-PGE concentrations, models which hypothesize that fluids alone were largely responsible for the economic concentration of the base and precious metals are not widely accepted. Determination of the trace element composition of magmatic volatile phases in such ore-forming systems can offer considerable insight into the origin of potentially mineralizing fluids in such igneous environments. Laser ablation ICP-MS microanalysis allows researchers to confirm the original metal budget of magmatic volatile phases and quantify the behavior of trace ore metals in the fluid phase in the absence of well-constrained theoretical or experimental predictions of ore metal solubility. In this study, we present new evidence from major deposits (Sudbury, Ontario, Canada; Stillwater Complex, Montana, U.S.A.) that compositionally distinct magmatic brines and halide melt phases were exsolved from crystallizing residual silicate melt and trapped within high-T fluid conduits now comprised of evolved rock compositions (albite-quartz graphic granite, orthoclase-quartz granophyre). Petrographic evidence demonstrates that brines and halide melts coexisted with immiscible carbonic phases at the time of entrapment (light aliphatic hydrocarbons, CO2). Brine and halide melt inclusions are rich in Na, Fe, Mn, K, Pb, Zn, Ba, Sr, Al and Cl, and homogenize by either halite dissolution at high T ( ˜450-700° C) or by melting of the salt phase (700-800° C). LA-ICPMS analyses of single inclusions demonstrate that high salinity volatile phases contained abundant base metals (Cu, Fe, Sn, Bi) and precious metals (Pt, Pd, Au, Ag) at the time of entrapment. Notably, precious metal concentrations in the inclusions are comparable to and often exceed the economic concentrations of the metals within the ores themselves. As a consequence of these results, current genetic models must be revised to consider the role played by hydrous saline melts and magmatic brines in deposit development, and the potential for interaction and competition between sulfide liquids (or PGE-bearing sulfide minerals) and hydrosaline volatiles for available PGE and Au in a crystallizing mafic igneous system must be critically evaluated.

  16. Theoretical predictions of properties and gas-phase chromatography behaviour of carbonyl complexes of group-6 elements Cr, Mo, W, and element 106, Sg

    NASA Astrophysics Data System (ADS)

    Pershina, V.; Anton, J.

    2013-05-01

    Fully relativistic, four-component density functional theory electronic structure calculations were performed for M(CO)6 of group-6 elements Cr, Mo, W, and element 106, Sg, with an aim to predict their adsorption behaviour in the gas-phase chromatography experiments. It was shown that seaborgium hexacarbonyl has a longer M-CO bond, smaller ionization potential, and larger polarizability than the other group-6 molecules. This is explained by the increasing relativistic expansion and destabilization of the (n - 1)d AOs with increasing Z in the group. Using results of the calculations, adsorption enthalpies of the group-6 hexacarbonyls on a quartz surface were predicted via a model of physisorption. According to the results, -?Hads should decrease from Mo to W, while it should be almost equal - within the experimental error bars - for W and Sg. Thus, we expect that in the future gas-phase chromatography experiments it will be almost impossible - what concerns ?Hads - to distinguish between the W and Sg hexacarbonyls by their deposition on quartz.

  17. Theoretical predictions of properties and gas-phase chromatography behaviour of carbonyl complexes of group-6 elements Cr, Mo, W, and element 106, Sg.

    PubMed

    Pershina, V; Anton, J

    2013-05-01

    Fully relativistic, four-component density functional theory electronic structure calculations were performed for M(CO)6 of group-6 elements Cr, Mo, W, and element 106, Sg, with an aim to predict their adsorption behaviour in the gas-phase chromatography experiments. It was shown that seaborgium hexacarbonyl has a longer M-CO bond, smaller ionization potential, and larger polarizability than the other group-6 molecules. This is explained by the increasing relativistic expansion and destabilization of the (n - 1)d AOs with increasing Z in the group. Using results of the calculations, adsorption enthalpies of the group-6 hexacarbonyls on a quartz surface were predicted via a model of physisorption. According to the results, -?Hads should decrease from Mo to W, while it should be almost equal--within the experimental error bars--for W and Sg. Thus, we expect that in the future gas-phase chromatography experiments it will be almost impossible--what concerns ?Hads--to distinguish between the W and Sg hexacarbonyls by their deposition on quartz. PMID:23656128

  18. Measurements of total atomic attenuation cross sections of Tm, Yb, Lu, Hf, Ta, W, Re and Os Elements at 122keV and 136keV

    SciTech Connect

    Kaya, N.; Tirasoglu, E.; Apaydin, G.; Kobya, A. I.

    2007-04-23

    The aim of this study was to measure the total atomic attenuation cross sections ({sigma}t) in eighth elements (69{<=}Z{<=}76) at 122 keV and 136 keV. The experimental values of the cross sections were determined using the transmission geometry. Measurements have been performed using an annular source (Co-57) and Ultra-LEGe solid state detector with a resolution of 150 eV at 5.9 keV. Experimental results have been compared with theoretically calculated values and other available experimental results. Good agreement was observed among the experimental, theoretical and other experimental values.

  19. Strength of the pnicogen bond in complexes involving group Va elements N, P, and As.

    PubMed

    Setiawan, Dani; Kraka, Elfi; Cremer, Dieter

    2015-03-01

    A set of 36 pnicogen homo- and heterodimers, R3E···ER3 and R3E···E?R?3, involving differently substituted group Va elements E = N, P, and As has been investigated at the ?B97X-D/aug-cc-pVTZ level of theory to determine the strength of the pnicogen bond with the help of the local E···E? stretching force constants k(a). The latter are directly related to the amount of charge transferred from an E donor lone pair orbital to an E? acceptor ?* orbital, in the sense of a through-space anomeric effect. This leads to a buildup of electron density in the intermonomer region and a distinct pnicogen bond strength order quantitatively assessed via k(a). However, the complex binding energy ?E depends only partly on the pnicogen bond strength as H,E-attractions, H-bonding, dipole-dipole, or multipole-multipole attractions also contribute to the stability of pnicogen bonded dimers. A variation from through-space anomeric to second order hyperonjugative, and skewed ?,? interactions is observed. Charge transfer into a ?* substituent orbital of the acceptor increases the absolute value of ?E by electrostatic effects but has a smaller impact on the pnicogen bond strength. A set of 10 dimers obtains its stability from covalent pnicogen bonding whereas all other dimers are stabilized by electrostatic interactions. The latter are quantified by the magnitude of the local intermonomer bending force constants XE···E?. Analysis of the frontier orbitals of monomer and dimer in connection with the investigation of electron difference densities, and atomic charges lead to a simple rationalization of the various facets of pnicogen bonding. The temperature at which a given dimer is observable under experimental conditions is provided. PMID:25325889

  20. [Pollution characteristics of platinum group elements in road rust in Xiamen].

    PubMed

    Hong, Zhen-yu; Hong, You-wei; Yin, Li-qian; Chen, Jin-sheng; Chen, Yan-ting; Xu, Ling-ling

    2015-01-01

    With the potential risks for the environment and human health, the concentration and distribution characteristics of platinum group element(PGEs) in road dust in Xiamen city were investigated. Road dust samples were collected from the traffic trunk road, tunnel, tourism area, and industrial area of Xiamen on October 2012. The samples were digested with aqua regia in a microwave assisted digestion system under high pressure condition, separated and purified with cation exchange resin( Dowex AG50W-X8), and the resulting solutions were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The results showed that the average concentrations(range) of Pd, Pt and Rh in road dust were 246.82 (58.68-765.52) ng x g(-1), 95.45 (42.14-371.36) ng x g(-1) and 51.76 (21.04-119.72) ng x g(-1), respectively, which were two orders of magnitude higher than the background values. Compared with other cities worldwide, the concentrations of Pd, Pt and Rh in road dust in Xiamen were at higher levels. Theconcentrations of PGEs for different functional areas were listed in the following order: tunnel > urban district > industrial area > tourism area, which indicated that their spatial distributions were mainly affected by the traffic intensity. Correlation analysis results showed that concentration of Pd in the urban traffic artery was significantly correlated with Rh, while Pt was not so correlated with Pd and Rh, suggesting that other sources contributed to PGEs in road dust in addition to the vehicle emission. Although motor vehicle traveling was banned in tourist area, the concentration of PGEs was still at a high level. Some of them might originate from the road dust in surrounding area by atmosphere diffusion. PMID:25898678

  1. Environmental routes for platinum group elements to biological materials--a review.

    PubMed

    Ek, Kristine H; Morrison, Gregory M; Rauch, Sebastien

    2004-12-01

    The increased use of platinum group elements (PGE) in automobile catalysts has led to concern over potential environmental and biological accumulation. Platinum (Pt), palladium (Pd) and rhodium (Rh) concentrations have increased in the environment since the introduction of automobile catalysts. This review summarises current knowledge concerning the environmental mobility, speciation and bioavailability of Pt, Pd and Rh. The greater proportion of PGE emissions is from automobile catalysts, in the form of nanometer-sized catalyst particles, which deposit on roadside surfaces, as evidenced in samples of road dust, grass and soil. In soil, PGE can be transformed into more mobile species through complexation with organic matter and can be solubilised in low pH rainwater. There are indications that environmentally formed Pd species are more soluble and hence more mobile in the environment than Rh and Pt. PGE can reach waterbodies through stormwater transport and deposition in sediments. Besides external contamination of grass close to roads, internal PGE uptake has been observed for plants growing on soil contaminated with automobile catalyst PGE. Fine particles of PGE were also detected on the surface of feathers sampled from passerines and raptors in their natural habitat, and internal organs of these birds also contained PGE. Uptake has been observed in sediment-dwelling invertebrates, and laboratory studies have shown an uptake of PGE in eel and fish exposed to water containing road dust. The available evidence indicates that the PGE, especially Pd, are transported to biological materials through deposition in roots by binding to sulphur-rich low molecular weight species in plants. PGE uptake to exposed animals have uptake rates in the following order: Pd>Pt>Rh. The liver and kidney accumulate the highest levels of PGE, especially Pd. Urinary Pd and Rh, but not Pt, levels are correlated with traffic intensity. Dental alloys may lead to elevated urinary Pt levels. Platinum is a well-known allergen and Pd also shows a strong sensitisation potential. PMID:15504490

  2. ROLE OF SURFACE FUNCTIONAL GROUPS IN THE CAPTURE OF ELEMENTAL MERCURY AND MERCURIC CHLORIDE BY ACTIVATED CARBONS

    EPA Science Inventory

    The paper discusses using a laboratory-scale, fixed bed apparatus to study the role of surface functional groups (SFGs) in the capture of mercuric chloride (HgC12) and elemental mercury (Hgo) in nitrogen (N2) prior to flue gas atmosphere studies. The study focused on two activat...

  3. Study on 12kV outdoor vacuum switch with replaceable HRC element drop out fuse

    SciTech Connect

    Wang Jiimei

    1996-12-31

    A new type of vacuum interrupter for 12kV outdoor vacuum switch was experimentally studied, the envelope of which was made of porcelain with petticoat flange for outdoor insulation. In order to produce an axial magnetic field and improve the capacity of transfer current in the vacuum interrupter, an iron plate of horse-shoe construction ingeniously designed was chosen as an electrode. The drop-out fuse with replaceable sand-filled HRC element in series with the vacuum switch is a new conception of design to increase breaking capacity. However, it is a vacuum switch of newly designed to form {open_quotes}a vacuum switch and drop-out type fuse combination{close_quotes}.

  4. Structural and functional evolution of group II intron ribozymes: insights from unusual elements carrying a 3' extension.

    PubMed

    Tourasse, Nicolas J; Stabell, Fredrik B; Kolstø, Anne-Brit

    2010-07-31

    Group II introns are large RNA elements that interrupt genes. They are self-splicing ribozymes that catalyze their own excision and mobile retroelements that can invade new genomic DNA sites. While group II introns typically consist of six structural domains, a number of elements containing an unusual 3' extension of 53-56 nucleotides have recently been identified. Bioinformatic and functional analyses of these introns have revealed that they belong to two evolutionary subgroups and that the 3' extension has a differential effect on the splicing reactions for introns of the two subgroups, a functional difference that may be related to structural differences between the introns. In addition, there is phylogenetic evidence that some introns are mobile with their extension. The unusual introns have provided dramatic examples of the structural and functional evolution of group II ribozymes that have been able to accommodate an extra segment into their compact structure while maintaining functionality. PMID:20219707

  5. Tensorial Formalism for Rovibronic Spectroscopy of C3v Molecules Spectroscopy of XY3Z (C3v) Molecules with AN Even or Odd Number of Electrons: a Tensorial Formalism Adapted to the SU(2)otimes CIsupset C? vSsupset C3vS Group Chain

    NASA Astrophysics Data System (ADS)

    Hilali, A. El; Boudon, V.

    2010-06-01

    In molecular spectroscopy, it is often considered that sophisticated group theoretical and tensorial formalism methods are only really useful for spherical top (i.e. highly symmetrical) molecules, for which they have proven their high efficiency. Consequently, it is usually admitted that symmetric and asymmetric tops (i.e. lower symmetry) species should be treated using more ``conventional'' methods. However, some key elements of the formalism developed in our group for tetrahedral or octahedral molecules can be used with great profit even for less symmetrical systems: the ability of performing systematic developments of all rovibrational interactions in case of complex polyads and the so-called ``vibrational extrapolation'' which makes global analyses much easier. Firstly, we present the development of a tensorial formalism adapted to the study of XY3Z type molecules which possess integer angular momenta (i.e. in a singlet electronic state) by using the O(3)supset C? vsupset C3v chain. We present also the C3v TDS(C3v Top Data System) software for spectrum simulation dedicated to the study of symmetric-top molecules belonging to the C3v point group. Secondly, we present the development of a tensorial formalism adapted to the study of XY_3Z type open-shell species which possess half-integer angular momenta by using the SU(2)otimes C_Isupset C? vSsupset C3vS group chain A. El Hilali, V. Boudon and M. Loete, J. Mol. Spectrosc., 234, 176-181 (2005). A. El Hilali, Ch. Wenger, V. Boudon and M. Loete, J. Quant. Spectrosc. Radiat. Transfert., accepted (2010). A. El Hilali, V. Boudon and M. Loete, J. Mol. Spectrosc., 239, 41-50 (2006). A. El Hilali, V. Boudon and M. Loete, J. Mol. Spectrosc., 253, 92-98 (2009). A. El Hilali, V. Boudon and M. Loete, J. Mol. Spectrosc., 234, 131-121 (2005).

  6. Survey of chimeric IStron elements in bacterial genomes: multiple molecular symbioses between group I intron ribozymes and DNA transposons.

    PubMed

    Tourasse, Nicolas J; Stabell, Fredrik B; Kolstø, Anne-Brit

    2014-11-10

    IStrons are chimeric genetic elements composed of a group I intron associated with an insertion sequence (IS). The group I intron is a catalytic RNA providing the IStron with self-splicing ability, which renders IStron insertions harmless to the host genome. The IS element is a DNA transposon conferring mobility, and thus allowing the IStron to spread in genomes. IStrons are therefore a striking example of a molecular symbiosis between unrelated genetic elements endowed with different functions. In this study, we have conducted the first comprehensive survey of IStrons in sequenced genomes that provides insights into the distribution, diversity, origin and evolution of IStrons. We show that IStrons have a restricted phylogenetic distribution limited to two bacterial phyla, the Firmicutes and the Fusobacteria. Nevertheless, diverse IStrons representing two major groups targeting different insertion site motifs were identified. This taken with the finding that while the intron components of all IStrons belong to the same structural class, they are fused to different IS families, indicates that multiple intron-IS symbioses have occurred during evolution. In addition, introns and IS elements related to those that were at the origin of IStrons were also identified. PMID:25324310

  7. Survey of chimeric IStron elements in bacterial genomes: multiple molecular symbioses between group I intron ribozymes and DNA transposons

    PubMed Central

    Tourasse, Nicolas J.; Stabell, Fredrik B.; Kolstø, Anne-Brit

    2014-01-01

    IStrons are chimeric genetic elements composed of a group I intron associated with an insertion sequence (IS). The group I intron is a catalytic RNA providing the IStron with self-splicing ability, which renders IStron insertions harmless to the host genome. The IS element is a DNA transposon conferring mobility, and thus allowing the IStron to spread in genomes. IStrons are therefore a striking example of a molecular symbiosis between unrelated genetic elements endowed with different functions. In this study, we have conducted the first comprehensive survey of IStrons in sequenced genomes that provides insights into the distribution, diversity, origin and evolution of IStrons. We show that IStrons have a restricted phylogenetic distribution limited to two bacterial phyla, the Firmicutes and the Fusobacteria. Nevertheless, diverse IStrons representing two major groups targeting different insertion site motifs were identified. This taken with the finding that while the intron components of all IStrons belong to the same structural class, they are fused to different IS families, indicates that multiple intron–IS symbioses have occurred during evolution. In addition, introns and IS elements related to those that were at the origin of IStrons were also identified. PMID:25324310

  8. Platinum group elements in a 3.5 Ga nickel-iron occurrence - Possible evidence of a deep mantle origin

    NASA Technical Reports Server (NTRS)

    Tredoux, Marian; Hart, Rodger J.; Lindsay, Nicholas M.; De Wit, Maarten J.; Armstrong, Richard A.

    1989-01-01

    This paper reports the results of new field observations and the geochemical analyses for the area of the Bon Accord (BA) (the Kaapvaal craton, South Africa) Ni-Fe deposit, with particular consideration given to the trace element, platinum-group element, and isotopic (Pb, Nd, and Os) compositions. On the basis of these data, an interpretation of BA is suggested, according to which the BA deposit is a siderophile-rich heterogeneity remaining in the deep mantle after a process of incomplete core formation. The implications of such a model for the study of core-mantle segregation and the geochemistry of the lowermost mantle are discussed.

  9. Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements of the Planets and Satellites

    USGS Publications Warehouse

    Davies, M.E.; Abalakin, V.K.; Cross, C.A.; Duncombe, R.L.; Masursky, H.; Morando, B.; Owen, T.C.; Seidelmann, P.K.; Sinclair, A.T.; Wilkins, G.A.; Tjuflin, Y.S.

    1980-01-01

    This paper is the entire report of the IAU Working Group on Cartographic Coordinates and Rotational Elements of the Planets and Satellites, including three annexes. Tables give the recemmended values for the directions of the north poles of rotation and the prime meridians of the planets and satellites. Reference surfaces for mapping these bodies are described. The annexes discuss the guiding principles, given in the body of the report, present explanatory notes, and provide a bibliography of the rotational elements and reference surfaces of the planets and satellites, definitions, and algebraic expressions of relevant parameters. ?? 1980 D. Reidel Publishing Co.

  10. 2015-2016 Verification Worksheet Dependent Student-Tracking Group V3

    E-print Network

    2015-2016 Verification Worksheet Dependent Student- Tracking Group V3 Your 2015-2016 Free (include apt. no.) Student's Date of Birth City State Zip Student's Email Address Student's Phone Number Student's Alternate or Cell Phone Number B. Child Support Paid Check the box that applies: No child

  11. Airy Functions for Compact Lie Groups. Rahul N. Fernandez and V. S. Varadarajan

    E-print Network

    Varadarajan, Veeravalli S.

    . The Airy function was discovered by the mathematician and as- tronomer Sir George Biddell Airy, who firstAiry Functions for Compact Lie Groups. Rahul N. Fernandez and V. S. Varadarajan Department of Mathematics University of California, Los Angeles, CA 90095-1555, USA. Abstract. The classical Airy function

  12. v1 -periodic homotopy groups of Sp(n) Martin Bendersky Donald M. Davis

    E-print Network

    Davis, Donald M.

    of the groups of SU(n). In Section 5, we apply our results to James numbers and exponents of actual homoto, James numbers yAll authors were partially supported by the National Science Foundation. Th* *e] by v-11ssn(X) = dirlimev-11ssn+1(X; Z=pe), (1.2) where

  13. Les Houches 2011: Physics at TeV Colliders New Physics Working Group Report

    E-print Network

    Brooijmans, G; Moortgat, F; Santiago, J; Skands, P; Vásquez, D Albornoz; Allanach, B C; Alloul, A; Arbey, A; Azatov, A; Baer, H; Balázs, C; Barr, A; Basso, L; Battaglia, M; Bechtle, P; Bélanger, G; Belyaev, A; Benslama, K; Bergström, L; Bharucha, A; Boehm, C; Bondarenko, M; Bondu, O; Boos, E; Boudjema, F; Bringmann, T; Brown, M; Bunichev, V; Calvet, S; Campanelli, M; Carmona, A; Cerdeño, D G; Chala, M; Chivukula, R S; Chowdhury, D; Christensen, N D; Cirelli, M; Cox, S; Cranmer, K; Da Silva, J; Delahaye, T; De Roeck, A; Djouadi, A; Dobson, E; Dolan, M; Donato, F; La Rochelle, G Drieu; Duda, G; Duhr, C; Dumont, B; Edsjö, J; Ellis, J; Evoli, C; Falkowski, A; Felcini, M; Fuks, B; Gabrielli, E; Gaggero, D; Gascon-Shotkin, S; Ghosh, D K; Giammanco, A; Godbole, R M; Gondolo, P; Goto, T; Grasso, D; Gris, P; Guadagnoli, D; Gunion, J F; Haisch, U; Hartgring, L; Heinemeyer, S; Hirsch, M; Hewett, J; Ismail, A; Jeltema, T; Kadastik, M; Kakizaki, M; Kannike, K; Khalil, S; Kneur, J-L; Krämer, M; Kraml, S; Kreiss, S; Lavalle, J; Leane, R; Lykken, J; Maccione, L; Mahmoudi, F; Mangano, M; Martin, S P; Maurin, D; Moreau, G; Moretti, S; Moskalenko, I; Moultaka, G; Muhlleitner, M; Niessen, I; O'Leary, B; Orlando, E; Panci, P; Polesello, G; Porod, W; Porter, T; Profumo, S; Prosper, H; Pukhov, A; Racioppi, A; Raidal, M; de Traubenberg, M Rausch; Renaud, A; Reuter, J; Rizzo, T G; Robens, T; Rodríguez-Marrero, A Y; Salati, P; Savage, C; Scott, P; Sekmen, S; Semenov, A; Shan, C -L; Shepherd-Themistocleous, C; Simmons, E H; Slavich, P; Speckner, C; Staub, F; Strong, A; Taillet, R; Thomas, F S; Thomas, M C; Tomalin, I; Tytgat, M; Ughetto, M; Valéry, L; Walker, D G E; Weiler, A; West, S M; White, C D; Williams, A J; Wingerter, A; Wymant, C; Yu, J -H; Yuan, C -P; Zerwas, D

    2012-01-01

    We present the activities of the "New Physics" working group for the "Physics at TeV Colliders" workshop (Les Houches, France, 30 May-17 June, 2011). Our report includes new agreements on formats for interfaces between computational tools, new tool developments, important signatures for searches at the LHC, recommendations for presentation of LHC search results, as well as additional phenomenological studies.

  14. Layered V-B-O polyoxometalate nets linked by diethylenetriamine complexes with dangling amine groups.

    PubMed

    Chen, Hong; Zhang, Yunfeng; Yu, Zheng-Bao; Sun, Junliang

    2014-11-01

    Two layered V-B-O contained polyoxometalate (POM) net structures, denoted as SUT-12 and SUT-13, are reported here. SUT-12 was synthesized by the boric acid flux method, and it represents the first 2D structure constructed from the V6B20 vanadoborate cluster. SUT-13 was synthesized by the hydrothermal method and constructed from V12B6P12 vanadium borophosphate clusters. In both structures, the vanadoborate or vanadium borophosphate clusters were linked through in situ formed Zn(DETA)2 or Cu(DETA)2 complexes. Surprisingly, for all DETA molecules in the two metal complexes, there is one dangling amine group when it is coordinated to the metal. The phenomenon of the dangling amine group feature is abnormal and the Cu(DETA)2 complexes in SUT-13 were taken as an example and studied by the density functional theory (DFT) calculations in order to understand this unusual feature. PMID:25182271

  15. First-principles study of group V and VII impurities in SnS2

    NASA Astrophysics Data System (ADS)

    Xia, Congxin; Zhao, Xu; Peng, Yuting; Zhang, Heng; Wei, Shuyi; Jia, Yu

    2015-09-01

    Based on density functional theory, the electronic structure, formation energy and transition level of group V and VII atoms-doped SnS2 are investigated by means of first-principles methods. Numerical results show that the formation energy and transition level are dependent highly on the atom number in the periodic table. Group V atom substituting S atom has high formation energy and can create deep acceptor impurity level inside the band gap of SnS2. However, our calculations also show that group VII atom substituting S atom may serve as a promising n-type doping in the SnS2 due to its negative formation energy and shallow transition level under the Sn-rich growth conditions.

  16. Thermochemistry of organic, elementorganic and inorganic species. Part XXI: Enthalpies of formation for bi- and triradicals of main group elements’ halogenides

    NASA Astrophysics Data System (ADS)

    Ponomarev, Dmitry; Takhistov, Viatcheslav; Slayden, Suzanne; Liebman, Joel

    2008-03-01

    General trends in thermochemistry of bi- and triradicals as the fragments of halogenated molecules of main group elements :EX (:EHX; :EX 2) and triradicals ·:EX, respectively, where X-halogens F-I were found for the first time. The enthalpy of formation for methylene CH 2 was drastically changed in present work with adopted values 79 ( 3B 1) and 88 ( 1A 1) compared with currently used values ˜93 and ˜102 kcal mol -1, respectively. This happened mainly because of the drastic change in the enthalpy of formation for ketene CH 2dbnd C dbnd O molecule from currently used value -11.4 to -24 kcal mol -1 [A.V. Golovin, D.A. Ponomarev, V.V. Takhistov, This Journal 524 (2000) 259] which was the source of experimental determination of ?Hf0 :CH 2. Other experimental data are provided for support of the lower values of the ?Hf0 for :CH 2. It was established that halogens F-I stabilize all biradicals :EX (E = B-Tl, N-Bi) and :EHX (:EX 2) (E = C-Pb) compared with the free radicals of these elements. This was interpreted by essentially smaller thermodynamic stability of bi- compared with mono (free)radicals the former extracting larger stabilization at H ? X replacement from the same halogen compared with more stable free radicals. The expected increase in stabilization of biradicals is observed when coming down the periodic table while due to lower stability of biradicals all halogens reveal similar (contrary to free radicals) stabilization effects. Finding unknown values and correcting some literature data on the enthalpies of formation for mono-, bi- and triradicals we could estimate their thermodynamic stabilities. It was established that only about 40 molecules, radicals and biradicals from more than 800 hydrides and halogenides possess higher?Hf0 values compared with their fragments with elements in lower valent states with H 2 (rarely HX) as a partner. This might be treated only in the sense that the parent species are less stable than the system [fragment + H 2 (or HX)] rather than as the support of the higher thermodynamic stability of an element in its lower valent state. The thermodynamic stability of such state may be found only by the comparison of the consecutive bond dissociation energies (BDEs) in parent molecules like PbH 3X ? ·PbH 2X (BDE 1) ? :PbHX (BDE 2) ? ·:PbX (BDE 3) and only if BDE 2 < 0 one can declare the larger thermodynamic stability of element in lower valent state. But this does not happen with any species studied in this work. This means that thermodynamic stability quite definitely decreases in the row molecule > free radical > biradical > triradical > :E: (C-Pb) contrary to the current opinion of larger thermodynamic stability of lower valent states for, say, thallium or lead. The detailed analysis of many computational results related to thermochemistry of halogenated main group elements is performed with quite definite result that neither ab initio, DFT, semi-empirical methods (or their combination) can be trusted either in support of known or prediction of unknown values of the enthalpies of formation while the empirical approach, elaborated in this work, solves the problem of calculation of the enthalpies of formation and search of general trends in structure/enthalpy of formation for halogenated main group elements.

  17. Photogrammetry and Laser Scanning for the Earth Sciencesworking Group V6

    NASA Astrophysics Data System (ADS)

    Chandler, J. H.; Buckley, S. J.; Rieke-Zapp, D.; Wackrow, R.

    2012-07-01

    With the UK gaining responsibility for Commission V at the Beijing Congress in 2008, there was an opportunity to create a new working group focusing on earth science applications at close range. The earth science community has had a long tradition of using close range photogrammetry, and more recently laser scanning, and such opportunities have not been fully recognised by ISPRS in the past. Formation of a new ISPRS Working Group helps to bridge this gap and promotes the skills of ISPRS members more widely. The purpose of this paper is to justify the creation of Working Group V6 and identify some of the activities conducted over the last four years. In particular, reference will be made to the various technical sessions which have been organised and supported across the world, the first resulting in a Special Issue of The Photogrammetric Record published in September 2010. In addition, Working Group V6 has been responsible for the creation of two freely available guidance documents entitled "tips for the effective use of digital close range photogrammetry and terrestrial laser scanning". The former focuses on close range digital photogrammetry and has developed through several iterations with input from both academic and industrial users from around the world. For this reason it should be of distinct value to new and perhaps non-expert users interested in using photogrammetry for earth science applications. The paper includes a discussion which considers whether the initial four years of activity have been successful. A superficial assessment based upon the number of members attracted worldwide would suggest that this has indeed been the case. A deeper comparison between proposed activities and those actually achieved suggest some discrepancy, which is perhaps inevitable as Working Group Officers clearly have other responsibilities. However, examination of papers published in the earth surface journals reveal high incidence of photogrammetry and laser scanning appearing in recent work. This should encourage members of Working Group V6 in future activities and collaborations.

  18. Isotope Anomalies in the Fe-group Elements in Meteorites and Connection to Nucleosynthesis in AGB Stars

    E-print Network

    Wasserburg, Gerald J; Busso, Maurizio

    2015-01-01

    We study the effects of neutron captures in AGB stars on \\oq Fe-group\\cqb elements, with an emphasis on Cr, Fe, and Ni. These elements show anomalies in $^{54}$Cr, $^{58}$Fe, and $^{64}$Ni in solar-system materials, which are commonly attributed to SNe. However, as large fractions of the interstellar medium (ISM) were reprocessed in AGB stars, these elements were reprocessed, too. We calculate the effects of such reprocessing on Cr, Fe, and Ni through 1.5\\msb and 3\\msb AGB models, adopting solar and 1/3 solar metallicities. All cases produce excesses of $^{54}$Cr, $^{58}$Fe, and $^{64}$Ni, while the other isotopes are little altered; hence, the observations may be explained by AGB processing. The results are robust and not dependent on the detailed initial isotopic composition. Consequences for other \\oq Fe group\\cqb elements are then explored. They include $^{50}$Ti excesses, and some production of $^{46,47,49}$Ti. In many circumstellar condensates, Ti quantitatively reflects these effects of AGB neutron cap...

  19. Calculating Three Loop Ladder and V-Topologies for Massive Operator Matrix Elements by Computer Algebra

    E-print Network

    J. Ablinger; A. Behring; J. Blümlein; A. De Freitas; A. von Manteuffel; C. Schneider

    2015-09-28

    Three loop ladder and $V$-topology diagrams contributing to the massive operator matrix element $A_{Qg}$ are calculated. The corresponding objects can all be expressed in terms of nested sums and recurrences depending on the Mellin variable $N$ and the dimensional parameter $\\varepsilon$. Given these representations, the desired Laurent series expansions in $\\varepsilon$ can be obtained with the help of our computer algebra toolbox. Here we rely on generalized hypergeometric functions and Mellin-Barnes representations, on difference ring algorithms for symbolic summation, on an optimized version of the multivariate Almkvist-Zeilberger algorithm for symbolic integration, and on new methods to calculate Laurent series solutions of coupled systems of differential equations. The solutions can be computed for general coefficient matrices directly for any basis also performing the expansion in the dimensional parameter in case it is expressible in terms of indefinite nested product-sum expressions. This structural result is based on new results of our difference ring theory. In the cases discussed we deal with iterative sum- and integral-solutions over general alphabets. The final results are expressed in terms of special sums, forming quasi-shuffle algebras, such as nested harmonic sums, generalized harmonic sums, and nested binomially weighted (cyclotomic) sums. Analytic continuations to complex values of $N$ are possible through the recursion relations obeyed by these quantities and their analytic asymptotic expansions. The latter lead to a host of new constants beyond the multiple zeta values, the infinite generalized harmonic and cyclotomic sums in the case of $V$-topologies.

  20. CSRL-V ENDF/B-V 227-group neutron cross-section library and its application to thermal-reactor and criticality safety benchmarks

    SciTech Connect

    Ford, W.E. III; Diggs, B.R.; Knight, J.R.; Greene, N.M.; Petrie, L.M.; Webster, C.C.; Westfall, R.M.; Wright, R.Q.; Williams, M.L.

    1982-01-01

    Characteristics and contents of the CSRL-V (Criticality Safety Reference Library based on ENDF/B-V data) 227-neutron-group AMPX master and pointwise cross-section libraries are described. Results obtained in using CSRL-V to calculate performance parameters of selected thermal reactor and criticality safety benchmarks are discussed.

  1. Micro V-Groove Grinding Technique of Large Germanium Immersion Grating Element for Mid-Infrared Spectrograph

    NASA Astrophysics Data System (ADS)

    Yin, Shaohui; Ohmori, Hitoshi; Uehara, Yoshihiro; Shimizu, Tomoyuki; Lin, Weimin

    The 8.2m SUBARU large space telescope in Hawaii requires a mid-infrared high dispersion spectrograph with a resolution of 200000 at 10µm which employs a Germanium Immersion Grating (GIG) element. For this, the GIG element with a large number of sharp and smooth micro V-grooves must be fabricated. Previous studies were focused on the fabrication of a prototype GIG element. The grinding system developed however was not applicable for the fabrication of practical larger GIG element due to insufficient machining space and fast wear of the small grinding wheel used. The ultimate goal of this project was therefore to develop a new grinding system capable of fabricating larger GIG elements for practical use. This paper discusses the results achieved in the first phase of the research, which focused on the principle of the grinding process and grinding system, as well as describes results of micro-truing and micro-grinding experiments using a #4000 metal bonded diamond grinding wheel. Wear variation of the grinding wheel and its effects on the corner radius of micro V-grooves are also discussed. The minimum wheel tip radius of 8.2µm was achieved using this #4000 grinding wheel by micro-truing, and V-groove corner radiuses ranging from 15µm to 25.8µm were also achieved using the same grinding wheel.

  2. 75 FR 35786 - Resale Power Group of Iowa, WPPI Energy v. ITC Midwest LLC, Interstate Power and Light Company...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-23

    ...DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket...Resale Power Group of Iowa, WPPI Energy v. ITC Midwest LLC, Interstate...Resale Power Group of Iowa and WPPI Energy filed a supplement to its complaint originally...

  3. Threat to Valued Elements of Life: The Experience of Dementia across Three Ethnic Groups

    ERIC Educational Resources Information Center

    Lawrence, Vanessa; Samsi, Kritika; Banerjee, Sube; Morgan, Craig; Murray, Joanna

    2011-01-01

    Purpose: There is a fundamental knowledge gap regarding the experience of dementia within minority ethnic groups in the United Kingdom and elsewhere. The present study examined the subjective reality of living with dementia from the perspective of people with dementia within the 3 largest ethnic groups in the United Kingdom. Design and Methods:…

  4. Method of loading organic materials with group III plus lanthanide and actinide elements

    DOEpatents

    Bell, Zane W. (Oak Ridge, TN); Huei-Ho, Chuen (Oak Ridge, TN); Brown, Gilbert M. (Knoxville, TN); Hurlbut, Charles (Sweetwater, TX)

    2003-04-08

    Disclosed is a composition of matter comprising a tributyl phosphate complex of a group 3, lanthanide, actinide, or group 13 salt in an organic carrier and a method of making the complex. These materials are suitable for use in solid or liquid organic scintillators, as in x-ray absorption standards, x-ray fluorescence standards, and neutron detector calibration standards.

  5. Deformation behavior of blended elemental ti-6ai-4v compacts

    NASA Astrophysics Data System (ADS)

    Welsch, G.; Lee, Y.-T.; Eloff, P. C.; Eylon, D.; Froes, F. H.

    1983-03-01

    A blended elemental Ti-6A1-4V alloy powder, sintered to 99 pct theoretical density, was tested in tension and fatigue and characterized by optical, scanning, and transmission electron microscopy and by X-ray energy dispersive analysis. The microstructure consisted of a combination of equiaxed and low aspect ratio lamellar alpha phase. Two types of pores were observed: macropores at grain boundaries or triple points, and micropores within alpha regions. Chemical homogeneity was achieved within individual alpha or beta regions with slight compositional fluctuations between different grains. The deformation modes in alpha regions were investigated by transmission electron microscopy on thin foils prepared from tensile and cyclically deformed specimens. Tensile deformation occurred by homogeneous slip on both prismatic and pyramidal alpha slip planes. In cyclic deformation, on the other hand, little slip activity was found except for some heterogeneous slip on the basal plane associated with a relatively large micropore. Micropores of ?0.5 ?m size were found to act as dislocation pinning sites.

  6. Finite Element Simulation of Machining of Ti6Al4V Alloy

    NASA Astrophysics Data System (ADS)

    Rizzuti, S.; Umbrello, D.

    2011-05-01

    Titanium and its alloys are an important class of materials, especially for aerospace applications, due to their excellent combination of strength and fracture toughness as well as low density. However, these materials are generally regarded as difficult to machine because of their low thermal conductivity and high chemical reactivity with cutting tool materials. Moreover, the low thermal conductivity of Titanium inhibits dissipation of heat within the workpiece causing an higher temperature at the cutting edge and generating for higher cutting speed a rapid chipping at the cutting edge which leads to catastrophic failure. In addition, chip morphology significantly influences the thermo-mechanical behaviour at the workpiece/tool interface, which also affects the tool life. In this paper a finite element analysis of machining of TiAl6V4 is presented. In particular, cutting force, chip morphology and segmentation are taken into account due to their predominant roles to determine machinability and tool wear during the machining of these alloys. Results in terms of residual stresses are also presented. Moreover, the numerical results are compared with experimental ones.

  7. Finite Element Simulation of Machining of Ti6Al4V Alloy

    SciTech Connect

    Rizzuti, S.; Umbrello, D.

    2011-05-04

    Titanium and its alloys are an important class of materials, especially for aerospace applications, due to their excellent combination of strength and fracture toughness as well as low density. However, these materials are generally regarded as difficult to machine because of their low thermal conductivity and high chemical reactivity with cutting tool materials. Moreover, the low thermal conductivity of Titanium inhibits dissipation of heat within the workpiece causing an higher temperature at the cutting edge and generating for higher cutting speed a rapid chipping at the cutting edge which leads to catastrophic failure. In addition, chip morphology significantly influences the thermo-mechanical behaviour at the workpiece/tool interface, which also affects the tool life.In this paper a finite element analysis of machining of TiAl6V4 is presented. In particular, cutting force, chip morphology and segmentation are taken into account due to their predominant roles to determine machinability and tool wear during the machining of these alloys. Results in terms of residual stresses are also presented. Moreover, the numerical results are compared with experimental ones.

  8. Atomically Thin Group V Elemental Films: Theoretical Investigations of Antimonene Allotropes

    E-print Network

    Pandey, Ravi

    with semiconducting elec- tronic properties. For example, the monolayer form of black phosphorus, phosphorene (-P, the most stable allotrope for P is black phosphorus, which is composed of AB stacked -P monolayers. The 2D form of the so-called blue phosphorus is referred to as -P5 which possesses the hexagonal

  9. Bismuth nano-droplets for group-V based molecular-beam droplet epitaxy

    SciTech Connect

    Li, C.; Zeng, Z. Q.; Hirono, Y.; Morgan, T. A.; Hu, X.; Salamo, G. J.; Fan, D. S.; Wu, J.; Yu, S. Q.; Wang, Zh. M.

    2011-12-12

    Self-assembly of bismuth droplets at nanoscale on GaAs(100) surface using molecular beam epitaxy was demonstrated. Fine control of density and size was achieved by varying growth temperature and total bismuth deposition. Droplet density was tuned by roughly 3 orders of magnitude, and the density-temperature dependence was found to be consistent with classical nucleation theory. These results may extend the flexibility of droplet epitaxy by serving as templates for group V based droplet epitaxy, which is in contrast to conventional group III based droplet epitaxy and may encourage nanostructure formation of bismuth-containing materials.

  10. Functionalization of phosphorescent emitters and their host materials by main-group elements for phosphorescent organic light-emitting devices.

    PubMed

    Yang, Xiaolong; Zhou, Guijiang; Wong, Wai-Yeung

    2015-12-01

    Phosphorescent organic light-emitting devices (OLEDs) have attracted increased attention from both academic and industrial communities due to their potential practical application in high-resolution full-color displays and energy-saving solid-state lightings. The performance of phosphorescent OLEDs is mainly limited by the phosphorescent transition metal complexes (such as iridium(iii), platinum(ii), gold(iii), ruthenium(ii), copper(i) and osmium(ii) complexes, etc.) which can play a crucial role in furnishing efficient energy transfer, balanced charge injection/transporting character and high quantum efficiency in the devices. It has been shown that functionalized main-group element (such as boron, silicon, nitrogen, phosphorus, oxygen, sulfur and fluorine, etc.) moieties can be incorporated into phosphorescent emitters and their host materials to tune their triplet energies, frontier molecular orbital energies, charge injection/transporting behavior, photophysical properties and thermal stability and hence bring about highly efficient phosphorescent OLEDs. So, in this review, the recent advances in the phosphorescent emitters and their host materials functionalized with various main-group moieties will be introduced from the point of view of their structure-property relationship. The main emphasis lies on the important role played by the main-group element groups in addressing the key issues of both phosphorescent emitters and their host materials to fulfill high-performance phosphorescent OLEDs. PMID:26245654

  11. Combined distillation and normal freezing to purify elements of groups II and VI

    NASA Technical Reports Server (NTRS)

    Holland, L. R.

    1984-01-01

    A practical system and its application to the purification of Te and Cd is described. Single crystals are grown directly in vitreous silica ampoules subsequently used for sealed Bridgman growth of (Hg-Cd)Te. The system also prepares the ampoules by heating in high vacuum. Purification of the elements is by the combined effect of distillation and normal freezing. Transport and segregation are discussed.

  12. Final Report: Main Group Element Chemistry in Service of Hydrogen Storage and Activation

    SciTech Connect

    David A. Dixon; Anthony J. Arduengo, III

    2010-09-30

    Replacing combustion of carbon-based fuels with alternative energy sources that have minimal environmental impact is one of the grand scientific and technological challenges of the early 21st century. Not only is it critical to capture energy from new, renewable sources, it is also necessary to store the captured energy efficiently and effectively for use at the point of service when and where it is needed, which may not be collocated with the collection site. There are many potential storage media but we focus on the storage of energy in chemical bonds. It is more efficient to store energy on a per weight basis in chemical bonds. This is because it is hard to pack electrons into small volumes with low weight without the use of chemical bonds. The focus of the project was the development of new chemistries to enable DOE to meet its technical objectives for hydrogen storage using chemical hydrogen storage systems. We provided computational chemistry support in terms of thermodynamics, kinetics, and properties prediction in support of the experimental efforts of the DOE Center of Excellence for Chemical Hydrogen Storage. The goal of the Center is to store energy in chemical bonds involving hydrogen atoms. Once the hydrogen is stored in a set of X-H/Y-H bonds, the hydrogen has to be easily released and the depleted fuel regenerated very efficiently. This differs substantially from our current use of fossil fuel energy sources where the reactant is converted to energy plus CO2 (coal) or CO2 and H2O (gasoline, natural gas), which are released into the atmosphere. In future energy storage scenarios, the spent fuel will be captured and the energy storage medium regenerated. This places substantial additional constraints on the chemistry. The goal of the computational chemistry work was to reduce the time to design new materials and develop materials that meet the 2010 and 2015 DOE objectives in terms of weight percent, volume, release time, and regeneration ability. This goal was met in terms of reducing the number of costly experiments and helping to focus the experimental effort on the potentially optimal targets. We have used computational chemistry approaches to predict the thermodynamic properties of a wide range of compounds containing boron, nitrogen, hydrogen, and other elements as appropriate including carbon. These calculations were done in most cases with high level molecular orbital theory methods that have small error bars on the order of ± 1 to 2 kcal/mol. The results were used to benchmark more approximate methods such as density functional theory for larger systems and for database development. We predicted reliable thermodynamics for thousands of compounds for release and regeneration schemes to aid/guide materials design and process design and simulation. These are the first reliable computed values for these compounds and for many represent the only available values. Overall, the computational results have provided us with new insights into the chemistry of main group and organic-base chemical hydrogen systems from the release of hydrogen to the regeneration of spent fuel. A number of experimental accomplishments were also made in this project. The experimental work on hydrogen storage materials centered on activated polarized ?- or ?-bonded frameworks that hold the potential for ready dihydrogen activation, uptake, and eventually release. To this end, a large number of non-traditional valence systems including carbenes, cyanocarbons, and C-B and and B-N systems were synthesized and examined. During the course of these studies an important lead arose from the novel valency of a class of stable organic singlet bi-radical systems. A synthetic strategy to an “endless” hydrogen storage polymer has been developed based on our cyanocarbon chemistry. A key issue with the synthetic efforts was being able to link the kinetics of release with the size of the substituents as it was difficult to develop a low molecular weight molecule with the right kinetics. A novel hydrogen activation process has been developed

  13. Measurement of the isotopic composition of the iron-group elements in the galactic cosmic radiation

    NASA Technical Reports Server (NTRS)

    Tarle, G.; Ahlen, S. P.; Cartwright, B. G.

    1978-01-01

    With an average mass resolution of approximately 0.65 amu the isotopic composition of Cr, Mn, Fe, and Ni in the galactic cosmic radiation has been measured for energies of about 300 to 600 MeV/amu at the detector. Large deviations from solar-system source composition reported by other workers are not observed.

  14. Threshold effects and renormalization group evolution of neutrino parameters in TeV scale seesaw models

    E-print Network

    Srubabati Goswami; Subrata Khan; Sasmita Mishra

    2013-10-05

    We consider the threshold effect on the renormalization group (RG) evolution of the neutrino masses and mixing angles in TeV scale seesaw models. We obtain the analytic expressions using the factorization method in presence of threshold effects. We also perform numerical study of RG effects in two specific low scale seesaw models following the bottom-up approach and ascertain the role of seesaw thresholds in altering the values of masses and mixing angles during RG evolution.

  15. A 21-group differential nuclear data covariance library based on ENDF/B-V. 2

    SciTech Connect

    Liaw, J.R.; Schmidt, R.R.

    1987-02-01

    The multigroup covariance processing code NJOY/ERRORR module has been used to process 15 major nuclides including actinides, coolant and structural materials common to most LMFBR design studies. Covariance files contained in ENDF/B-V.2 were processed into a 21-group covariance library. These covariance data will be used in estimating uncertainties of various performance and safety parameters of advanced liquid metal reactors currently being investigated at Argonne National Laboratory in order to establish the confidence level of our calculations.

  16. Process for forming shaped group III-V semiconductor nanocrystals, and product formed using process

    DOEpatents

    Alivisatos, A. Paul (Oakland, CA); Peng, Xiaogang (Fayetteville, AR); Manna, Liberato (Palo del Colle, IT)

    2001-01-01

    A process for the formation of shaped Group III-V semiconductor nanocrystals comprises contacting the semiconductor nanocrystal precursors with a liquid media comprising a binary mixture of phosphorus-containing organic surfactants capable of promoting the growth of either spherical semiconductor nanocrystals or rod-like semiconductor nanocrystals, whereby the shape of the semiconductor nanocrystals formed in said binary mixture of surfactants is controlled by adjusting the ratio of the surfactants in the binary mixture.

  17. The group separation of the rare-earth elements and yttrium from geologic materials by cation-exchange chromatography

    USGS Publications Warehouse

    Crock, J.G.; Lichte, F.E.; Wildeman, T.R.

    1984-01-01

    Demand is increasing for the determination of the rare-earth elements (REE) and yttrium in geologic materials. Due to their low natural abundance in many materials and the interferences that occur in many methods of determination, a separation procedure utilizing gradient strong-acid cation-exchange chromatography is often used to preconcentrate and isolate these elements from the host-rock matrix. Two separate gradient strong-acid cation-exchange procedures were characterized and the major elements as well as those elements thought to provide the greatest interference for the determination of the REE in geologic materials were tested for separation from the REE. Simultaneous inductively coupled argon plasma-atomic emission spectroscopy (ICAP-AES) measurements were used to construct the chromatograms for the elution studies, allowing the elution patterns of all the elements of interest to be determined in a single fraction of eluent. As a rock matrix, U.S. Geological Survey standard reference BCR-1 basalt was digested using both an acid decomposition procedure and a lithium metaborate fusion. Hydrochloric and nitric acids were tested as eluents and chromatograms were plotted using the ICAP-AES data; and we observed substantial differences in the elution patterns of the REE and as well as in the solution patterns of Ba, Ca, Fe and Sr. The nitric acid elution required substantially less eluent to elute the REE and Y as a group when compared to the hydrochloric acid elution, and provided a clearer separation of the REE from interfering and matrix elements. ?? 1984.

  18. Theoretical predictions of properties and gas-phase chromatography behaviour of bromides of group-5 elements Nb, Ta, and element 105, Db

    NASA Astrophysics Data System (ADS)

    Pershina, V.; Anton, J.

    2012-01-01

    Fully relativistic, four-component density functional theory electronic structure calculations were performed for MBr5, MOBr3, MBr6-, KMBr6, and MBr5Cl- of group-5 elements Nb, Ta, and element 105, Db, with the aim to predict adsorption behaviour of the bromides in gas-phase chromatography experiments. It was shown that in the atmosphere of HBr/BBr3, the pentabromides are rather stable, and their stability should increase in the row Nb < Db < Ta. Several mechanisms of adsorption were considered. In the case of adsorption by van der Waals forces, the sequence in volatility of the pentabromides should be Nb < Ta < Db, being in agreement with the sublimation enthalpies of the Nb and Ta pentabromides. In the case of adsorption by chemical forces (on a quartz surface modified with KBr/KCl), formation of the MBr5L- (L = Cl, Br) complex should occur, so that the volatility should change in an opposite way, i.e., Nb > Ta > Db. This sequence is in agreement with the one observed in the "one-atom-at-a-time" chromatography experiments. Some other scenarios, such as surface oxide formation were also considered but found to be irrelevant.

  19. Common data elements for pediatric traumatic brain injury: recommendations from the working group on demographics and clinical assessment.

    PubMed

    Adelson, P David; Pineda, Jose; Bell, Michael J; Abend, Nicholas S; Berger, Rachel P; Giza, Christopher C; Hotz, Gillian; Wainwright, Mark S

    2012-03-01

    The Common Data Elements (CDEs) initiative is a National Institutes of Health (NIH) interagency effort to standardize naming, definitions, and data structure for clinical research variables. Comparisons of the results of clinical studies of neurological disorders have been hampered by variability in data coding, definitions, and procedures for sample collection. The CDE project objective is to enable comparison of future clinical trials results in major neurological disorders, including traumatic brain injury (TBI), stroke, multiple sclerosis, and epilepsy. As part of this effort, recommendations for CDEs for research on TBI were developed through a 2009 multi-agency initiative. Following the initial recommendations of the Working Group on Demographics and Clinical Assessment, a separate workgroup developed recommendations on the coding of clinical and demographic variables specific to pediatric TBI studies for subjects younger than 18 years. This article summarizes the selection of measures by the Pediatric TBI Demographics and Clinical Assessment Working Group. The variables are grouped into modules which are grouped into categories. For consistency with other CDE working groups, each variable was classified by priority (core, supplemental, and emerging). Templates were produced to summarize coding formats, guide selection of data points, and provide procedural recommendations. This proposed standardization, together with the products of the other pediatric TBI working groups in imaging, biomarkers, and outcome assessment, will facilitate multi-center studies, comparison of results across studies, and high-quality meta-analyses of individual patient data. PMID:21939389

  20. Transfer of scarlet fever-associated elements into the group A Streptococcus M1T1 clone.

    PubMed

    Ben Zakour, Nouri L; Davies, Mark R; You, Yuanhai; Chen, Jonathan H K; Forde, Brian M; Stanton-Cook, Mitchell; Yang, Ruifu; Cui, Yujun; Barnett, Timothy C; Venturini, Carola; Ong, Cheryl-Lynn Y; Tse, Herman; Dougan, Gordon; Zhang, Jianzhong; Yuen, Kwok-Yung; Beatson, Scott A; Walker, Mark J

    2015-01-01

    The group A Streptococcus (GAS) M1T1 clone emerged in the 1980s as a leading cause of epidemic invasive infections worldwide, including necrotizing fasciitis and toxic shock syndrome. Horizontal transfer of mobile genetic elements has played a central role in the evolution of the M1T1 clone, with bacteriophage-encoded determinants DNase Sda1 and superantigen SpeA2 contributing to enhanced virulence and colonization respectively. Outbreaks of scarlet fever in Hong Kong and China in 2011, caused primarily by emm12 GAS, led to our investigation of the next most common cause of scarlet fever, emm1 GAS. Genomic analysis of 18 emm1 isolates from Hong Kong and 16 emm1 isolates from mainland China revealed the presence of mobile genetic elements associated with the expansion of emm12 scarlet fever clones in the M1T1 genomic background. These mobile genetic elements confer expression of superantigens SSA and SpeC, and resistance to tetracycline, erythromycin and clindamycin. Horizontal transfer of mobile DNA conferring multi-drug resistance and expression of a new superantigen repertoire in the M1T1 clone should trigger heightened public health awareness for the global dissemination of these genetic elements. PMID:26522788

  1. Transfer of scarlet fever-associated elements into the group A Streptococcus M1T1 clone

    PubMed Central

    Ben Zakour, Nouri L.; Davies, Mark R.; You, Yuanhai; Chen, Jonathan H. K.; Forde, Brian M.; Stanton-Cook, Mitchell; Yang, Ruifu; Cui, Yujun; Barnett, Timothy C.; Venturini, Carola; Ong, Cheryl-lynn Y.; Tse, Herman; Dougan, Gordon; Zhang, Jianzhong; Yuen, Kwok-Yung; Beatson, Scott A.; Walker, Mark J.

    2015-01-01

    The group A Streptococcus (GAS) M1T1 clone emerged in the 1980s as a leading cause of epidemic invasive infections worldwide, including necrotizing fasciitis and toxic shock syndrome123. Horizontal transfer of mobile genetic elements has played a central role in the evolution of the M1T1 clone45, with bacteriophage-encoded determinants DNase Sda16 and superantigen SpeA27 contributing to enhanced virulence and colonization respectively. Outbreaks of scarlet fever in Hong Kong and China in 2011, caused primarily by emm12 GAS8910, led to our investigation of the next most common cause of scarlet fever, emm1 GAS89. Genomic analysis of 18 emm1 isolates from Hong Kong and 16 emm1 isolates from mainland China revealed the presence of mobile genetic elements associated with the expansion of emm12 scarlet fever clones1011 in the M1T1 genomic background. These mobile genetic elements confer expression of superantigens SSA and SpeC, and resistance to tetracycline, erythromycin and clindamycin. Horizontal transfer of mobile DNA conferring multi-drug resistance and expression of a new superantigen repertoire in the M1T1 clone should trigger heightened public health awareness for the global dissemination of these genetic elements. PMID:26522788

  2. Geometric grouping of repeated elements within Frederik Schaffalitzky and Andrew Zisserman

    E-print Network

    Zisserman, Andrew

    of repeating operation in the world as well as groupers based on these. These groupers are demonstrated as a basis for a grouping al­ gorithm (a grouper) because of the following properties: it is global across projection, i.e. it does not require a weak perspective approximation. A grouper for this parametrized

  3. Which Social Elements Are Visible in Virtual Groups? Addressing the Categorization of Social Expressions

    ERIC Educational Resources Information Center

    Perez-Mateo, M.; Guitert, M.

    2012-01-01

    Learning is a social process. That is why it is extremely important to understand how students interact socially in online courses and how it affects the learning process. However, social aspects, understood as those expressions or comments that go beyond strictly academic interaction, i.e. the need to carry out group work, are not clearly…

  4. Comparison between steady-state and dynamic I-V measurements from a single-cell thermionic fuel element

    SciTech Connect

    Wernsman, B.

    1997-01-01

    A comparison between steady-state and dynamic I-V measurements from a single-cell thermionic fuel element (TFE) is made. The single-cell TFE used in this study is the prototype for the 40kW{sub e} space nuclear power system that is similar to the 6kW{sub e} TOPAZ-II. The steady-state I-V measurements influence the emitter temperature due to electron cooling. Therefore, to eliminate the steady-state I-V measurement influence on the TFE and provide a better understanding of the behavior of the thermionic energy converter and TFE characteristics, dynamic I-V measurements are made. The dynamic I-V measurements are made at various input power levels, cesium pressures, collector temperatures, and steady-state current levels. From these measurements, it is shown that the dynamic I-V{close_quote}s do not change the TFE characteristics at a given operating point. Also, the evaluation of the collector work function from the dynamic I-V measurements shows that the collector optimization is not due to a minimum in the collector work function but due to an emission optimization. Since the dynamic I-V measurements do not influence the TFE characteristics, it is believed that these measurements can be done at a system level to understand the influence of TFE placement in the reactor as a function of the core thermal distribution. {copyright} {ital 1997 American Institute of Physics.}

  5. Comparison between steady-state and dynamic I-V measurements from a single-cell thermionic fuel element

    SciTech Connect

    Wernsman, Bernard

    1997-01-10

    A comparison between steady-state and dynamic I-V measurements from a single-cell thermionic fuel element (TFE) is made. The single-cell TFE used in this study is the prototype for the 40 kW{sub e} space nuclear power system that is similar to the 6 kW{sub e} TOPAZ-II. The steady-state I-V measurements influence the emitter temperature due to electron cooling. Therefore, to eliminate the steady-state I-V measurement influence on the TFE and provide a better understanding of the behavior of the thermionic energy converter and TFE characteristics, dynamic I-V measurements are made. The dynamic I-V measurements are made at various input power levels, cesium pressures, collector temperatures, and steady-state current levels. From these measurements, it is shown that the dynamic I-V's do not change the TFE characteristics at a given operating point. Also, the evaluation of the collector work function from the dynamic I-V measurements shows that the collector optimization is not due to a minimum in the collector work function but due to an emission optimization. Since the dynamic I-V measurements do not influence the TFE characteristics, it is believed that these measurements can be done at a system level to understand the influence of TFE placement in the reactor as a function of the core thermal distribution.

  6. Isotope Anomalies in the Fe-group Elements in Meteorites and Connections to Nucleosynthesis in AGB Stars

    NASA Astrophysics Data System (ADS)

    Wasserburg, G. J.; Trippella, O.; Busso, M.

    2015-05-01

    We study the effects of neutron captures in AGB stars on “Fe-groupelements, with an emphasis on Cr, Fe, and Ni. These elements show anomalies in 54Cr, 58Fe, and 64Ni in solar system materials, which are commonly attributed to supernovae (SNe). However, as large fractions of the interstellar medium (ISM) were reprocessed in AGB stars, these elements were reprocessed, too. We calculate the effects of such reprocessing on Cr, Fe, and Ni through 1.5 {{M}? } and 3 {{M}? } AGB models, adopting solar and 1/3 solar metallicities. All cases produce excesses of 54Cr, 58Fe, and 64Ni, while the other isotopes are little altered; hence, the observations may be explained by AGB processing. The results are robust and not dependent on the detailed initial isotopic composition. Consequences for other “Fe groupelements are then explored. They include 50Ti excesses and some production of 46,47,49Ti. In many circumstellar condensates, Ti quantitatively reflects these effects of AGB neutron captures. Scatter in the data results from small variations (granularity) in the isotopic composition of the local ISM. For Si, the main effects are instead due to variations in the local ISM from different SN sources. The problem of Ca is discussed, particularly with regard to 48Ca. The measured data are usually represented assuming terrestrial values for 42Ca/44Ca. Materials processed in AGB stars or sources with variable initial 42Ca/44Ca ratios can give apparent 48Ca excesses/deficiencies, attributed to SNe. The broader issue of galactic chemical evolution is also discussed in view of the isotopic granularity in the ISM.

  7. Multiple magma evolution and ore-forming processes of the Hongge layered intrusion, SW China: Insights from Sr-Nd isotopes, trace elements and platinum-group elements

    NASA Astrophysics Data System (ADS)

    Liao, Mingyang; Tao, Yan; Song, Xieyan; Li, Yubang; Xiong, Feng

    2015-12-01

    The Hongge layered intrusion (259 Ma), which is located in the inner zone of the Emeishan large igneous province (ELIP), is one of the most typical Fe-Ti-V ore deposits in the Pan-Xi area. Mafic-ultramafic layered intrusions of the ELIP have attracted a lot of attention lately because these intrusions host world class Fe-Ti-V oxide deposits plus interesting Cu-Ni-(PGE) mineralization which may have economic potential. This paper, reports new whole-rock major and trace element compositions, PGE abundances and Sr-Nd isotopic data for selected cumulate rocks and basalts. We use these data to investigate the nature of parental magmas and the controls on its evolution from the source mantle en route to the surface involving the Hongge ore-bearing intrusion. Two abrupt changes in Mt/Ilm and trace element ratios such as Ba/Th with depths in the Hongge layered intrusion indicate that this intrusion formed by at least two pluses of relatively primitive magma. The whole rock Sr-Nd isotopic data of basaltic and intrusive rocks plot in the region of Emeishan low-Ti basalts and the compositions of residual liquid (at ?1260 °C and 1155 °C) calculated by MELTS are similar to our actual high-Ti (BFQ-2) and low-Ti (BC-1) basltic samples, indicate they are co-magmatic rather than derivation from a distinct source. Total PGE abundances in the Hongge samples are extremely low, ranging from 0.5 to 10 ppb. Sulfide-bearing rocks in the Hongge intrusion and the nearby coeval Banfangqing and Baicao basalts have similar mantle-like Pd/Pt ratios (2-6) and extremely high Cu/Pd ratios (3 × 104 to 4 × 105), indicating that sulfide segregation took place at depth prior to emplacement at Hongge and eruption in this region. Sulfide saturation in the Hongge magma may have resulted from such crustal contamination event. Crystallization of silicate minerals under the anhydrous magma, magma hydration plus Fe-Ti enrichments in the parental magma are three critical factors for the formation of Fe-Ti oxide ore layers in the Hongge intrusion.

  8. Average bond energies between boron and elements of the fourth, fifth, sixth, and seventh groups of the periodic table

    NASA Technical Reports Server (NTRS)

    Altshuller, Aubrey P

    1955-01-01

    The average bond energies D(gm)(B-Z) for boron-containing molecules have been calculated by the Pauling geometric-mean equation. These calculated bond energies are compared with the average bond energies D(exp)(B-Z) obtained from experimental data. The higher values of D(exp)(B-Z) in comparison with D(gm)(B-Z) when Z is an element in the fifth, sixth, or seventh periodic group may be attributed to resonance stabilization or double-bond character.

  9. Osmium-Isotope and Platinum-Group-Element Systematics of Impact-Melt Rocks, Chesapeake Bay Impact Structure, Virginia, USA

    NASA Technical Reports Server (NTRS)

    Lee, Seung Ryeol; Wright Horton, J., Jr.; Walker, Richard J.

    2005-01-01

    Osmium (Os) isotopes and platinum-group elements (PGEs) are useful for geochemically identifying a meteoritic component within impact structures, because meteorites are typically characterized by low (187)Os/(188)Os ratios and high PGE concentrations. In contrast, most types of crustal target rocks have high radiogenic Os and very low PGE concentrations. We have examined Os isotope and PGE systematics of impact-melt rocks and pre-impact target rocks from a 2004 test hole in the late Eocene Chesapeake Bay impact structure and from nearby coreholes. Our goal is to determine the proportion of the projectile component in the melt rock Additional information is included in the original extended abstract.

  10. Mobilization of the platinum group elements by low-temperature fluids: Implications for mineralization and the iridium controversy

    NASA Technical Reports Server (NTRS)

    Dowling, Kim; Keays, Reid R.; Wallace, Malcolm W.; Gostin, Victor A.

    1992-01-01

    Geochemical investigations on the widely dispersed Late Proterozoic Acraman impact ejecta horizon and its host marine shales in the Adelaide Geosyncline provide strong evidence for low-temperature mobilization of the platinum group elements (PGE), including Ir. The ejecta horizon was formed when the middle Proterozoic dacitic volcanics in the Gawler Ranges, central South Australia, were impacted by a very large (ca. 4 km) meteorite. The resulting structure, now represented by Lake Acraman, is Australia's largest meteorite impact structure. Debris from the impact was blasted for many hundreds of kilometers, some falling into the shallow sea of the Adelaide Geosyncline, some 300 km to the east of the impact site.

  11. Heavy-ion double charge exchange reactions: a tool towards 0v\\b{eta}\\b{eta} nuclear matrix elements

    E-print Network

    Cappuzzello, F; Agodi, C; Bond`?, M; Carbone, D; Cunsolo, A; Foti, A

    2015-01-01

    The knowledge of the nuclear matrix elements for the neutrinoless double beta decay is fundamental for neutrino physics. In this paper, an innovative technique to extract information on the nuclear matrix elements by measuring the cross section of a double charge exchange nuclear reaction is proposed. The basic point is that the initial and final state wave functions in the two processes are the same and the transition operators are similar. The double charge exchange cross sections can be factorized in a nuclear structure term containing the matrix elements and a nuclear reaction factor. First pioneering experimental results for the 40Ca(18O,18Ne)40Ar reaction at 270 MeV incident energy show that such cross section factorization reasonably holds for the crucial 0+ --> 0+ transition to 40Args, at least at very forward angles.

  12. Heavy-ion double charge exchange reactions: a tool towards 0v\\b{eta}\\b{eta} nuclear matrix elements

    E-print Network

    F. Cappuzzello; M. Cavallaro; C. Agodi; M. Bond`?; D. Carbone; A. Cunsolo; A. Foti

    2015-11-12

    The knowledge of the nuclear matrix elements for the neutrinoless double beta decay is fundamental for neutrino physics. In this paper, an innovative technique to extract information on the nuclear matrix elements by measuring the cross section of a double charge exchange nuclear reaction is proposed. The basic point is that the initial and final state wave functions in the two processes are the same and the transition operators are similar. The double charge exchange cross sections can be factorized in a nuclear structure term containing the matrix elements and a nuclear reaction factor. First pioneering experimental results for the 40Ca(18O,18Ne)40Ar reaction at 270 MeV incident energy show that such cross section factorization reasonably holds for the crucial 0+ --> 0+ transition to 40Args, at least at very forward angles.

  13. Trace element analysis of obsidian artifacts from a classic Maya residential group at Nohmul, Belize

    SciTech Connect

    Hammond, N.; Neivens, M.D.; Harbottle, G.

    1984-01-01

    Forty-nine obsidian artifacts from a classic period residential group at Nohmul, northern Belize, have been analyzed by neutron activation analysis. The majority of the samples originated from Ixtepeque, and the remainder from El Chayal. Increasing prominence of the Ixtepeque source from the late Classic into the Terminal Classic (i.e., before and after ca. A.D. 800) suggests greater use of a coastal distribution route known to have originated in the formative and to have remained in use through the colonial period.

  14. Finite element solution of the multi-group neutron diffusion equation applied to the hypothetical core disruptive accident

    SciTech Connect

    Baldasaro, P.F.

    1980-01-01

    A two-dimensional (r,z), space-time-energy dependent calculational method has been developed for use in LMFBR hypothetical core disruptive accident (HCDA) analyses which utilizes the Finite Element Method (subsequently referred to as FEM) for the necessary diffusion theory neutronics calculations.The hydrodynamic portion of the calculation is performed with a modified form of the VENUS-I computer program which does a thermodynamic energy balance and uses an energy-density-dependent equation-of-state to calculate the pressures which cause reactor disassembly. The reactivity feedback which results from material motion is based on a Hermite Finite Element neutronics method in (r,z) geometry. The FEM neutronic calculations are done using an Eulerian coordinate system while the VENUS calculations employ a Lagrangian coordinate system. A unique feature of the FEM calculations is that the use of Hermite finite elements allows the analytic construction of iteration matrices. The numerical solution of the resulting system of equations utilizes direct matrix inversion which helps to minimize computing time. The major disadvantage of this method, relative to the standard finite differencing method (FDM), is the additional computational logic which is required. This application of the FEM demonstrates the potential which the method has for providing fast, accurate, and reliable solutions to the multi-group neutron diffusion problem where the effects of local heterogeneities are minimal.

  15. Distribution of platinum-group elements in the Bati Kef chromite deposit, Guleman-Elazig area, eastern Turkey.

    USGS Publications Warehouse

    Page, N.J.; Engin, T.; Singer, D.A.; Haffty, J.

    1984-01-01

    The distribution of platinum-group elements (PGE) within chromite deposits from an ophiolite is determined and their geochemistry compared with chromitites from ophiolites and from stratiform layered complexes elsewhere in the world. The Guleman area chromitites are lenses of layered massive to disseminated chromite in dunite or sheared harzburgite along and near the dunite-harzburgite contact. PGE were analysed by a fire assay/spectrographic method. The analyses, in ppb, varied narrowly near the detection limits; only Ir was mostly detected (24-27 ppb) . The data plot as independent, slight variations of individual PGE with crude and irregular spatial distributions, oriented with respect to the land surface. Based on studies elsewhere, the PGE reside mostly in laurite, erlichmanite and Os/Ir alloys included within or interstitial to chromite. Average values for each PGE were normalized with respect to average chondrite concentrations for these elements. All patterns for ophiolite-chromitites (5) show depletion of these elements relative to chondrite average concentrations, with greater depletion in Pt and Pd than in Ir and Ru, to produce patterns with negative slopes. Chromitites from differentiated stratiform complexes (2) yield patterns with positive slopes. -G.J.N.

  16. Growth Mechanism of Self-Catalyzed Group III?V Nanowires

    PubMed Central

    2010-01-01

    Group III?V nanowires offer the exciting possibility of epitaxial growth on a wide variety of substrates, most importantly silicon. To ensure compatibility with Si technology, catalyst-free growth schemes are of particular relevance, to avoid impurities from the catalysts. While this type of growth is well-documented and some aspects are described, no detailed understanding of the nucleation and the growth mechanism has been developed. By combining a series of growth experiments using metal?organic vapor phase epitaxy, as well as detailed in situ surface imaging and spectroscopy, we gain deeper insight into nucleation and growth of self-seeded III?V nanowires. By this mechanism most work available in literature concerning this field can be described. PMID:20939507

  17. Experimental and theoretical investigation of encounter of a group of particles with protecting elements of spacecraft

    NASA Astrophysics Data System (ADS)

    Zelepugin, S. A.; Konyaev, A. A.; Sidorov, V. N.; Khorev, I. E.; Yakushev, V. K.

    2008-12-01

    We present the results of comprehensive experimental and theoretical investigations of encounter with a barrier of a group of bodies thrown with a high-velocity. Throwing of a group of particles (from two to twelve bodies) was realized on a ballistic route using powder and light-gas units of different calibers in the range of velocities 500 3500 m/s. The process of particle throwing was controlled by acting aerodynamic forces. In experiments on collisions with barriers of a finite thickness (which imitates the protective shield of spacecraft) the number of particles in a homogeneous stream was varied from 2 to 7 at changing the flux density (distances between particles). Experimental data are obtained on variations of the area and mass of back-surface splinters. Numerical calculations simulated a knock of 2 to 4 particles against a barrier in the cases of normal impact and at an angle. The calculations were performed in three-dimensional formulation and applying criteria of complete destruction of material. The appearance of additional destruction centers in the barrier due to mutual influence of particles is revealed. Simple criteria are obtained for estimating the degree of interference of particles and the character of barrier destruction.

  18. Platinum group elements and gold in ferromanganese crusts from Afanasiy-Nikitin seamount, equatorial Indian Ocean: Sources and fractionation

    USGS Publications Warehouse

    Banakar, V.K.; Hein, J.R.; Rajani, R.P.; Chodankar, A.R.

    2007-01-01

    The major element relationships in ferromanganese (Fe-Mn) crusts from Afanasiy-Nikitin seamount (ANS), eastern equatorial Indian Ocean, appear to be atypical. High positive correlations (r = 0.99) between Mn/Co and Fe/Co ratios, and lack of correlation of those ratios with Co, Ce, and Ce/Co, indicate that the ANS Fe-Mn crusts are distinct from Pacific seamount Fe-Mn crusts, and reflect region-specific chemical characteristics. The platinum group elements (PGE: Ir, Ru, Rh, Pt, and Pd) and Au in ANS Fe-Mn crusts are derived from seawater and are mainly of terrestrial origin, with a minor cosmogenic component. The Ru/Rh (0.5-2) and Pt/Ru ratios (7-28) are closely comparable to ratios in continental basalts, whereas Pd/Ir ratios exhibit values ( 0.75) correlations between water depth and Mn/Co, Fe/Co, Ce/Co, Co, and the PGEs. Fractionation of the PGE-Au from seawater during colloidal precipitation of the major-oxide phases is indicated by well-defined linear positive correlations (r > 0.8) of Co and Ce with Ir, Ru, Rh, and Pt; Au/Co with Mn/Co; and by weak or no correlations of Pd with water depth, Co-normalized major-element ratios, and with the other PGE (r < 0.5). The strong enrichment of Pt (up to 1 ppm) relative to the other PGE and its positive correlations with Ce and Co demonstrate a common link for the high concentrations of all three elements, which likely involves an oxidation reaction on the Mn-oxide and Fe-oxyhydroxide surfaces. The documented fractionation of PGE-Au and their positive association with redox sensitive Co and Ce may have applications in reconstructing past-ocean redox conditions and water masses.

  19. Continuum in the X-Z---Y weak bonds: Z= main group elements.

    PubMed

    Joy, Jyothish; Jose, Anex; Jemmis, Eluvathingal D

    2016-01-15

    The Continuum in the variation of the X-Z bond length change from blue-shifting to red-shifting through zero- shifting in the X-Z---Y complex is inevitable. This has been analyzed by ab-initio molecular orbital calculations using Z= Hydrogen, Halogens, Chalcogens, and Pnicogens as prototypical examples. Our analysis revealed that, the competition between negative hyperconjugation within the donor (X-Z) molecule and Charge Transfer (CT) from the acceptor (Y) molecule is the primary reason for the X-Z bond length change. Here, we report that, the proper tuning of X- and Y-group for a particular Z- can change the blue-shifting nature of X-Z bond to zero-shifting and further to red-shifting. This observation led to the proposal of a continuum in the variation of the X-Z bond length during the formation of X-Z---Y complex. The varying number of orbitals and electrons available around the Z-atom differentiates various classes of weak interactions and leads to interactions dramatically different from the H-Bond. Our explanations based on the model of anti-bonding orbitals can be transferred from one class of weak interactions to another. We further take the idea of continuum to the nature of chemical bonding in general. © 2015 Wiley Periodicals, Inc. PMID:26279192

  20. Topological properties of phosphorene-like monolayer group V semiconductor compounds: a first-principles study

    E-print Network

    Yu, Weiyang; Niu, Chun-Yao; Li, Chong; Cho, Jun-Hyung; Jia, Yu

    2015-01-01

    To broaden the scope of layered group V semiconductors, we propose a class of phosphorenelike monolayer group V semiconductor compounds, such as PN, AsP, SbP and BiP with black-phosphorus-like alpha-phase and blue-phosphorus-like beta-phase, respectively. Using first-principles density functional theory calculations, we study yet unrealized structural phases of these compounds. We find the black-phosphorus-like alpha-phase to be almost equally stable as the blue-phosphorus-like beta-phase. alpha-phase compounds display a direct band gap, while beta-phase compounds display an indirect band gap. Both alpha-phase and beta-phase monolayers depends sensitively on the in-layer strain, as is studied with alpha- and beta- AsP and BiP. Further more, We find that alpha-BiP presents an intriguing topological state when gained a compress from -8% to -10%, offering an unprecedented tunability in structural and electronic properties of BiP compound.

  1. Cipollone v. Liggett Group, Inc. strengthens federal preemption defense in pesticide tort litigation

    SciTech Connect

    Stevens, R.W.

    1993-12-31

    When the United States Supreme Court held that the Federal Cigarette Labeling and Advertising Act (Cigarette Act) of 1969 preempted plaintiff`s failure to warn claims in Cipollone v. Liggett Group, Inc., the decision directly affected a far wider range of product liability cases than those involving only cigarettes. This article analyzes how Cipollone affects the defense raised in pesticide injury cases that the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) preempts state common law failure to warn claims. The Eleventh Circuit in Papas v. Upjohn Co. (Papas I), declining to follow contrary authority, held that FIFRA impliedly preempted state law claims that pesticides were inadequately labeled. On a petition for certiorari, the Supreme Court remanded the case back to the Eleventh Circuit for reconsideration in light of Cipollone. Recently, the Eleventh Circuit in Papas v. Upjohn Co. (Papas II) applied Cipollone to hold that FIFRA expressly preempts the state law claims. This article argues that Papas II correctly held, after Cipollone, that FIFRA preempts the state inadequate labeling and failure to warn claims in pesticide cases. 86 refs.

  2. The differential regulation of group II(A) and group V low molecular weight phospholipases A(2) in cultured rat astrocytes.

    PubMed

    Thomas, G; Bertrand, F; Saunier, B

    2000-04-14

    In astrocytes, cytokines stimulate the release of secretory phospholipase A(2) (sPLA(2)) activity and group II(A) sPLA(2) expression. This paper reports that two sPLA(2) isoforms, group II(A) and group V, are in fact expressed by astrocytes. Our studies showed that tumor necrosis factor alpha (TNFalpha) enhanced the mRNA of both isoforms, but the time courses of enhancement differed; group V was induced much faster than group II(A). Moreover, TNFalpha stimulated both the NF-kappaB and mitogen-activated protein (MAP) kinase (extracellular signal-regulated kinase, c-Jun NH(2)-terminal kinase, and p38 MAP kinase) signaling pathways in astrocytes. Interestingly, PI 3-kinase activity also was enhanced by TNFalpha, and NF-kappaB pathway was involved in mediating its effect. Specific inhibitors were used to show that both extracellular signal-regulated kinase and p38 MAP kinase may contribute to the effect of TNFalpha and that blocking phosphatidylinositol 3-kinase activity fully reversed the effect of TNFalpha. Furthermore, in astrocytes, TNFalpha-induced release of sPLA(2) activity was partially reversed by thyroid hormone and almost abolished by growth factors. This phenomenon was accompanied by a less marked increase in both group II(A) and group V sPLA(2) mRNA. In the presence of growth factors, the increase in group V mRNA was inhibited early and transiently, in contrast to what was observed with group II(A), which was more persistently inhibited. Although a transcriptional effect of thyroid hormone or growth factors in astrocytes cannot be definitively excluded, both types of factor interfered with sPLA(2) expression in a manner suggesting the existence of regulation of post-transcriptional events. PMID:10753884

  3. Creep deformation and fracture of a Cr/Mo/V bolting steel containing selected trace-element additions

    NASA Astrophysics Data System (ADS)

    Larouk, Z.; Pilkington, R.

    1999-08-01

    The article reports the creep behavior, at 565 °C, of 1Cr1Mo0.75V (Ti, B) (Durehete D1055) steel, in each of two grain sizes and doped with individual trace elements such as P, As, and Sn, in comparison to a reference cast of the base material containing 0.08 wt pct Ti. The addition of the trace elements P, As, or Sn (each <0.045 wt pct) appears to produce no significant effect on creep strength or creep crack-growth resistance at 565 °C. The fine-grained material shows low creep strength but notch strengthening, while the coarse-grained material shows higher creep strength and exhibits notch weakening for test times up to 2750 hours. From creep crack-growth tests, it appears that the C* parameter is not appropriate for correlating the creep crack-growth rate under the present test conditions. The parameters K I or ? net are found to correlate better, but, from the present data, it is not possible to judge which of these parameters is more appropriate for general use. It is suggested that the presence of Ti in CrMoV steels has an inhibiting effect on trace-element embrittlement.

  4. Finite element modeling of the morphology of ? to ? phase transformation in Ti-6Al-4V alloy

    NASA Astrophysics Data System (ADS)

    Katzarov, I.; Malinov, S.; Sha, W.

    2002-04-01

    In the present work, a mathematical model and computer programs were developed for numerical simulation of the processes of nucleation and growth of the ?-phase Widmanstätten plates during the course of the ? ? ? phase transformation in a Ti-6Al-4V alloy. The ?-phase appearance at the grain boundary of ? phase is described by a numerical procedure for random nucleation as a function of the vanadium concentration and the temperature. The rate at which an interface moves depends both on the intrinsic mobility and on the rate at which diffusion can remove the excess of vanadium atoms ahead of the interface. The finite-element method (FEM) was used for solving the diffusion equation on the domain occupied by ? phase. The elements chosen have dimensions in both space and time. A computer code based on the finite-element modeling and the volume of fluids method was developed to trace the movement of the ?/? interface. The influences of the cooling rate and the temperature of isothermal exposure on the Widmanstätten morphology were simulated and analyzed. The developed models and program packages are capable of one-dimensional (1-D) and two-dimensional (2-D) simulations of the morphology of the ? ? ? phase transformation in Ti-6Al-4V alloy for continuous cooling with any cooling path and for an arbitrary combination between continuous cooling and isothermal exposure.

  5. Platinum-group elements in rocks from the voikar-syninsky ophiolite complex, Polar Urals, U.S.S.R.

    USGS Publications Warehouse

    Page, N.J.; Aruscavage, P. J.; Haffty, J.

    1983-01-01

    Analyses of platinum-group elements (PGE) in rocks collected from the Voikar-Syninsky ophiolite in the Polar Urals suggest that the distribution and geochemistry of PGE in this Paleozoic ophiolite are similar to those in Mesozoic ophiolites from elsewhere. Chondrite-normalized PGE patterns for chromitite, the tectonite unit, and ultramafic and mafic cumulate unit have negative slopes. These results are similar to those found for chromitites from other ophiolites; stratiform chromities show positive slopes. If the magmas that form both types of chromitite originate from similar mantle source material with respect to PGE content, the processes involved must be quite different. However, the distinct chondrite-normalized PGE patterns may reflect differing source materials. ?? 1983 Springer-Verlag.

  6. Batch leaching tests of motherboards to assess environmental contamination by bromine, platinum group elements and other selected heavy metals.

    PubMed

    Almeida, César; Grosselli, Melina; González, Patricia; Martínez, Dante; Gil, Raúl

    2016-02-01

    In this study, a batch leaching test was executed to evaluate the toxicity associated with chemicals contained in motherboards. The leaching solutions used were distilled water, nitric acid, acetic acid and synthetic acid rain solution. A total of 21 elements including Ag, As, Au, Br, Cd, Co, Cr, Cu, Hf, Ir, Mn, Ni, Os, Pb, Pd, Pt, Rd, Rh, Se, U and Zn were analyzed. In this study, the pH values of all the leachates fell within the range of 2.33-4.88. The highest concentrations of metals were obtained from the acid rain solution, whilst the maximum value of bromine was achieved with solution of acetic acid. Appreciable concentrations of platinum group elements were detected with concentrations around 3.45, 1.43, 1.21 and 22.19 µg L(-1) for Ir, Pd, Pt and Rh, respectively. The different leaching of the motherboards revealed the predominant presence of the toxic substances in the leached from the e-waste. PMID:26343021

  7. Element distribution patterns in the ordovician Galena group, Southeastern Minnesota: Indicators of fluid flow and provenance of terrigenous material

    USGS Publications Warehouse

    Lively, R.S.; Morey, G.B.; Mossler, J.H.

    1997-01-01

    As part of a regional geochemical investigation of lower Paleozoic strata in the Hollandale embayment of southeastern Minnesota, elemental concentrations in acid-insoluble residues were determined for carbonate rock in the Middle Ordovician Galena Group. Elemental distribution patterns within the insoluble residues, particularly those of Ti, Al, and Zr, show that the Wisconsin dome and the Wisconsin arch, which contributed sediment to the embayment prior to Galena time, continued as weak sources of sediment during this period. In contrast, trace metals commonly associated with Mississippi Valley-type lead-zinc mineralization, including Pb, Zn, Cu, Ag, Ni, Co, As, and Mo, show dispersal patterns that are independent of those associated with primary depositional phenomena. These trace metals are concentrated in southern Minnesota in carbonate rocks near the interface between limestone- and dolostone-dominated strata. Dispersal patterns imply that the metals were carried by a north-flowing regional ground-water system. The results show that the geochemical attributes of insoluble residues can be used to distinguish provenance and transport directions of primary sediments within a depositional basin from effects of subsequent regional ground-water flow systems.

  8. Low keV electron probe analysis of silicate minerals for Mg, Al, and Si using pure-element standards

    NASA Technical Reports Server (NTRS)

    Cunningham, G. G.

    1972-01-01

    Accurate electron probe values for Mg, Al, and Si in silicate minerals may be obtained with pure-element standards. Analysis must be done at low (6 kV) accelerating potential and for best results, the average atomic number of the sample should be within about plus or minus 1 of the atomic number of the pure-element standard. This last requirement is automatically fulfilled for most common silicate minerals, as their average atomic numbers usually fall within the 11 to 15 range. Examples studied include a wet-chemically analyzed cordierite containing 17.71 weight percent Al, for which a value of 17.6 plus or minus 0.3 percent was obtained with the electron probe, and a hornblende containing 19.15 percent Si, which gave 19.0 plus or minus 0.3 percent using the probe method.

  9. Bactericidal Properties of Human and Murine Groups I, II, V, X, and XII Secreted Phospholipases A2*

    E-print Network

    Gelb, Michael

    , and Escherichia coli. The rank order potency among human sPLA2s against Gram-positive bacteria is group IIA > X and macrophage cell lines (7, 8). Recently, several new murine and human sPLA2s have been cloned and shownBactericidal Properties of Human and Murine Groups I, II, V, X, and XII Secreted Phospholipases A2

  10. nan0sphere: Location-Driven Fiction for Groups of Users Kevin Eustice, V. Ramakrishna, Alison Walker,

    E-print Network

    California at Los Angeles, University of

    nan0sphere: Location-Driven Fiction for Groups of Users Kevin Eustice, V. Ramakrishna, Alison@cs.ucla.edu Abstract. We developed a locative fiction application called nan0sphere and deployed it on the UCLA campus and challenges of group interactions in locative fiction, infrastructure required to support such applications

  11. Strain induced topological phase transitions in monolayer honeycomb structures of group-V binary compounds

    PubMed Central

    Nie, Yaozhuang; Rahman, Mavlanjan; Wang, Daowei; Wang, Can; Guo, Guanghua

    2015-01-01

    We present first-principles calculations of electronic structures of a class of two-dimensional (2D) honeycomb structures of group-V binary compounds. Our results show these new 2D materials are stable semiconductors with direct or indirect band gaps. The band gap can be tuned by applying lattice strain. During their stretchable regime, they all exhibit metal-indirect gap semiconductor-direct gap semiconductor-topological insulator (TI) transitions with increasing strain from negative (compressive) to positive (tensile) values. The topological phase transition results from the band inversion at the ? point which is due to the evolution of bonding and anti-bonding states under lattice strain. PMID:26656257

  12. Unveiling transient GaAs/GaP nanowire growth behavior using group V oscillations

    NASA Astrophysics Data System (ADS)

    Boulanger, J. P.; LaPierre, R. R.

    2014-02-01

    Patterned arrays of gold-assisted vapor-liquid-solid (VLS) nanowires (NWs) were grown on Si(111) substrates by gas source molecular beam epitaxy (MBE). GaAs/GaP heterostructures were grown with periodic modulation of the group V composition. Study of these oscillations by high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) enabled the measurement of the instantaneous growth rate throughout the NW. Novel transient growth behavior, NW dissolution, droplet purging, and droplet refilling were observed to occur at the GaAs/GaP hetero-interface. These behaviors were linked to the large change in chemical potential difference between the liquid droplet and the crystal solid when switching between As and P.

  13. Strain induced topological phase transitions in monolayer honeycomb structures of group-V binary compounds.

    PubMed

    Nie, Yaozhuang; Rahman, Mavlanjan; Wang, Daowei; Wang, Can; Guo, Guanghua

    2015-01-01

    We present first-principles calculations of electronic structures of a class of two-dimensional (2D) honeycomb structures of group-V binary compounds. Our results show these new 2D materials are stable semiconductors with direct or indirect band gaps. The band gap can be tuned by applying lattice strain. During their stretchable regime, they all exhibit metal-indirect gap semiconductor-direct gap semiconductor-topological insulator (TI) transitions with increasing strain from negative (compressive) to positive (tensile) values. The topological phase transition results from the band inversion at the ? point which is due to the evolution of bonding and anti-bonding states under lattice strain. PMID:26656257

  14. Major and trace element composition of copiapite-group minerals and coexisting water from the Richmond mine, Iron Mountain, California

    USGS Publications Warehouse

    Jamieson, H.E.; Robinson, C.; Alpers, C.N.; McCleskey, R.B.; Nordstrom, D.K.; Peterson, Ronald C.

    2005-01-01

    Copiapite-group minerals of the general formula AR4 (SO4)6(OH)2??nH2O, where A is predominantly Mg, Fe2+, or 0.67Al3+, R is predominantly Fe3+, and n is typically 20, are among several secondary hydrous Fe sulfates occurring in the inactive mine workings of the massive sulfide deposit at Iron Mountain, CA, a USEPA Superfund site that produces extremely acidic drainage. Samples of copiapite-group minerals, some with coexisting water, were collected from the Richmond mine. Approximately 200 mL of brownish pore water with a pH of -0.9 were extracted through centrifugation from a 10-L sample of moist copiapite-group minerals taken from pyritic muck piles. The pore water is extremely rich in ferric iron (Fe3+=149 g L-1, FeT=162 g L-1 and has a density of 1.52 g mL-1. The composition of the pore water is interpreted in the context of published phase relations in the Fe2O3- SO3-H2O system and previous work on the chemistry of extremely acid mine waters and associated minerals in the Richmond mine. Two distinct members of the copiapite mineral group were identified in the samples with coexisting water: (1) abundant magnesiocopiapite consisting of platy crystals 10 to 50 ??m and (2) minor aluminocopiapite present as smaller platy crystals that form spheroidal aggregates. The average composition (n=5) of the magnesiocopiapite is (Mg0.90Fe0.172+ Zn0.02Cu0.01)???1.10(Fe3.833+Al0.09)???3.92(SO4) 6.00(OH)1.96??20H2O. Bulk compositions determined by digestion and wet-chemical analysis are consistent with the microanalytical results. These results suggest that magnesiocopiapite is the least soluble member of the copiapite group under the prevailing conditions. Micro-PIXE analysis indicates that the copiapite-group minerals in this sample sequester Zn (average 1420 ppm), with lesser amounts of Cu (average 270 ppm) and As (average 64 ppm). ?? 2004 Elsevier B.V. All rights reserved.

  15. Platinum-group elements in the Eastern Deccan volcanic province and a comparison with platinum metals of the western Deccan

    NASA Astrophysics Data System (ADS)

    Crocket, James; Paul, Dalim; Lala, Trisha

    2013-08-01

    This study is the first detailed investigation of the platinum-group elements (PGE) at the eastern margin of the Deccan volcanic province of India. One of the PGE, osmium, is not included largely because of analytical problems. The study is focused on mafic volcanics and dykes from four areas including Amarkantak, Umaria, Shahdol and Chirimiri. The first two localities represent two lava piles of about 170 and 400 m thickness respectively. In Umaria, 16 flows have been demarcated based on petrography and field studies. The Shahdol samples are basal lava formations overlying Gondwana sediments (Carboniferous) and the Chirimiri samples are dykes. In this study, the western Deccan province is defined as the Western Ghats plus Kutch. On average, the PGE are ~20% higher in Amarkantak than Umaria and the flows are ~13% higher in PGE than the dykes. A Zr vs. Pd scattergram found a strong positive correlation for these two elements except for one Umaria sample which indicated severe Pd loss. A comparison of west and east parts of the Deccan volcanic province using primitive mantle normalization showed that higher values prevailed in the western province suite in the Ni-Ir-Ru-Pt region. In contrast, eastern province values dominated in the Pd-Au-Cu region at the `Cu' end of the profiles. A strong dominance of Pd in the eastern Deccan was also of interest. A number of factors, for example, percentage partial melting of the source rock and the temperature and pressure of partial melting strongly influence the character of these profiles. The observed PGE profile characteristics probably result in part from a long distance of subsurface transport of Deccan magma from the western to eastern regions.

  16. Optimization of parameters for semiempirical methods V: Modification of NDDO approximations and application to 70 elements

    PubMed Central

    2007-01-01

    Several modifications that have been made to the NDDO core-core interaction term and to the method of parameter optimization are described. These changes have resulted in a more complete parameter optimization, called PM6, which has, in turn, allowed 70 elements to be parameterized. The average unsigned error (AUE) between calculated and reference heats of formation for 4,492 species was 8.0 kcal mol?1. For the subset of 1,373 compounds involving only the elements H, C, N, O, F, P, S, Cl, and Br, the PM6 AUE was 4.4 kcal mol?1. The equivalent AUE for other methods were: RM1: 5.0, B3LYP 6–31G*: 5.2, PM5: 5.7, PM3: 6.3, HF 6–31G*: 7.4, and AM1: 10.0 kcal mol?1. Several long-standing faults in AM1 and PM3 have been corrected and significant improvements have been made in the prediction of geometries. Figure Calculated structure of the complex ion [Ta6Cl12]2+ (footnote): Reference value in parenthesis Electronic supplementary material The online version of this article (doi:10.1007/s00894-007-0233-4) contains supplementary material, which is available to authorized users. PMID:17828561

  17. Effect of process parameters on deep drawing of Ti-6Al-4V alloy using finite element analysis

    NASA Astrophysics Data System (ADS)

    Kotkunde, Nitin; Deole, Aditya D.; Gupta, A. K.; Singh, S. K.

    2013-12-01

    Deep drawing process depends on the large number of process parameters and their interdependence. Optimization of process parameters in deep drawing is a vital task to reduce manufacturing cost and understand their influence on the deformation behaviour of the sheet metal. In this paper, significance of important process parameters namely, punch speed, blank holder pressure (BHP) and temperature on the deep-drawing characteristics of a Ti-6Al-4V alloy are investigated. Taguchi technique was employed to identify the influence of these parameters on thickness distribution. The finite element model of deep drawing process has been built up and analyzed using Dynaform version 5.6.1 with LS-Dyna version 971 as solver. Based on the predicted thickness distribution of the deep drawn circular cup and analysis of variance (ANOVA) results, it is concluded that punch speed has the greatest influence on the deep drawing of Ti-6Al-4V alloy blank sheet. Temperature and BHP effect are negligible in deep drawing of Ti-6Al-4V alloy at low warm temperatures (less than 450°C) but it may contribute to a significant extent at higher temperature. Also thickness distribution is predicted using artificial neural network (ANN). It is observed that the predicted thickness distribution is in good agreement with the experimental data.

  18. Thermal Evaporation Synthesis and Properties of ZnO Nano/Microstructures Using Carbon Group Elements as the Reducing Agents

    PubMed Central

    2010-01-01

    ZnO nano/microstructures have been formed by thermal evaporation method using ZnO powders mixed with carbon group elements (C, Si, Ge, Sn, or Pb) as the reducing agent. For cases of mixed precursors of ZnO/C, ZnO/Si, and ZnO/Ge, the pure ZnO nano/microstructures are realized, while for ZnO/Sn (ZnO/Pb) systems, the phase of Pb2O3(Zn2SnO4) generally are represented in the ZnO products. The appearance of Pb2O3(Zn2SnO4) is attributed to the lower melting point and higher vapor pressure of Sn (Pb) in the heating and evaporation processes. The morphologies and sizes of the products are controlled by adjusting the growth regions and/or introducing gaseous argon. Room temperature (RT) photoluminescence spectra indicate that the intensity (peak position) of the ultraviolet emission is increased (redshift) due to the existence of Zn2SnO4 phase in the ZnO products. The Pb2O3(Zn2SnO4) phase in ZnO nano/microstructures plays a important role in enhancing the saturation magnetizations of RT ferromagnetism with respect to the case of pure ZnO products fabricated by the precursor of mixed ZnO and graphite. PMID:20672143

  19. The effects of group-I elements co-doping with Mn in ZnO dilute magnetic semiconductor

    NASA Astrophysics Data System (ADS)

    Zhang, Liqiang; Zhang, Yinzhu; Ye, Zhizhen; Lu, Jianguo; Lu, Bin; He, Bo

    2012-06-01

    Mn-Li codoped ZnO (Zn(Mn,Li)O), Mn-Na codoped ZnO (Zn(Mn,Na)O), and Mn-K codoped ZnO (Zn(Mn,K)O) thin films were deposited on quartz substrates by pulsed laser deposition. The doping effects of group-I elements (e.g., Li, Na, and K) on the structural, magnetic, and optical properties of the Mn doped ZnO (ZnMnO) films were discussed. X-ray diffraction and K-edge x-ray absorption near-edge structure measurements revealed that all the films showed a hexagonal wurtzite ZnO structure, and no other clusters, precipitates, or second phases were detected. Zn(Mn,Na)O and Zn(Mn,Li)O films showed a weak p-type conductivity, while the Zn(Mn,K)O film appeared a highly resistivity. The saturation magnetization of Zn(Mn,Na)O and Zn(Mn,Li)O films was 1.2 and 0.18 ?B/Mn, respectively. The hole-related defects, induced by doping with a low content of Li or Na, contributed to the room temperature ferromagnetism in the ZnMnO system.

  20. Platinum group elements provide no indication of a meteoritic component in ICDP cores from the Bosumtwi crater, Ghana

    NASA Astrophysics Data System (ADS)

    Goderis, S.; Tagle, R.; Schmitt, R. T.; Erzinger, J.; Claeys, P. H.

    In an attempt to identify the type of projectile, 14 samples from the Bosumtwi crater in Ghana were analyzed for platinum group element (PGE) concentrations by nickel sulfide fire assay inductively coupled plasma-mass spectrometry (ICP-MS). The majority of the samples come from the impactite material recovered by cores LB-07A and LB-08A, which were drilled by the International Continental Scientific Drilling program (ICDP). One sample originates from the fallback material found at the contact between the impactite and the overlying lake sediment in core LB-05B. No clear signature of a meteoritic contamination was identified in the 13 impactite samples. The target rock apparently dominates the PGE contribution in the impactites. These results agree with the PGE concentrations reported for the suevites collected at the crater rim and in other parts of the Bosumtwi ICDP cores. However, based on Cr and Os isotopic signatures, a meteoritic component could be present in the sample of fallback material, supporting the reports of the existence of meteoritic material in the Ivory Coast tektites. Further analyses of the fallback material from the Bosumtwi drill cores should confirm (or not) this first result.

  1. Interactions of 200 GeV gold nuclei in light elements

    NASA Technical Reports Server (NTRS)

    Brewster, N. R.; Fickle, R. K.; Waddington, C. J.; Binns, W. R.; Israel, M. H.; Jones, M. D.; Klarmann, J.; Garrard, T. L.; Newport, B. J.; Stone, E. C.

    1983-01-01

    Total charge-changing cross sections and partial cross-sections for interactions of 200 GeV Au-197 nuclei incident on carbon and polyethylene (CH2) targets have been measured during a calibration of the HEAO-3 Heavy Nuclei Experiment. From these, the total and partial cross-sections for Au-197 incident on hydrogen are inferred. The effects of using these cross-sections in one model of cosmic ray propagation are illustrated. Comparisons to predictions using semi-empirical formulas are shown.

  2. Fragmentation Cross Sections of 290 and 400 MeV/nucleon 12C Beamson Elemental Targets

    SciTech Connect

    Zeitlin, C.; Guetersloh, S.; Heilbronn, L.; Miller, J.; Fukumura,A.; Iwata, Y.; Murakami, T.

    2007-03-17

    Charge-changing and fragment production cross sections at 0circ have been obtained for interactions of 290 MeV/nucleon and 400MeV/nucleon carbon beams with C, CH2, Al, Cu, Sn, and Pb targets. Thesebeams are relevant to cancer therapy, space radiation, and the productionof radioactive beams. We compare to previously published results using Cand CH2 targets at similar beam energies. Due to ambiguities arising fromthe presence of multiple fragments on many events, previous publicationshave reported only cross sections for B and Be fragments. In this work wehave extracted cross sections for all fragment species, using dataobtained at three distinct values of angular acceptance, supplemented bydata taken with the detector stack placed off the beam axis. A simulationof the experiment with the PHITS Monte Carlo code shows fair agreementwith the data obtained with the large acceptance detectors, but agreementis poor at small acceptance. The measured cross sections are alsocompared to the predictions of the one-dimensional cross section modelsEPAX2 and NUCFRG2; the latter is presently used in NASA's space radiationtransport calculations. Though PHITS and NUCFRG2 reproduce thecharge-changing cross sections with reasonable accuracy, none of themodels is able to accurately predict the fragment cross sections for allfragment species and target materials.

  3. Finite element simulation of conventional and prestressed cutting of Ti6Al4V

    NASA Astrophysics Data System (ADS)

    Peng, Ruitao; Tang, Xinzi; Tan, Yuanqiang; Liu, Xiongwei

    2013-05-01

    Titanium alloys are known as difficult-to-machine materials, chip morphology plays a predominant role in determining machinability and tool wear during the machining of titanium alloys. Based on the finite element analysis and experimental validation, the cutting processes in conventional cutting and prestressed cutting of titanium alloy ring parts were explored respectively. The Johnson-Cook model expressed by equivalent plastic strain flow stress is utilized to describe the constitutive properties. A ductile fracture criterion based on the strain energy is applied to model the crack initiation and evolution during the chip segmentation. Cutting force as well as distributions of stress, temperature and equivalent plastic strain along cutting time were numerically compared. The results indicate that in conventional cutting and prestressed cutting, chips show the similar characteristic of continuous and regular serrated shape. Initial stress distribution of workpiece was changed by prestress, which correspondingly leads to the alteration of stress distribution in the subsurface layer. Prestress hardly influences the distributions of temperature and equivalent plastic strain on workpiece. The cutting force curves share the same average amplitude and analogous undulating rhythm.

  4. L-shell polarization and alignment of heavy elements induced by 59.54keV photons.

    PubMed

    Ozdemir, Y; Durak, R; Kacal, M R; Kurudirek, M

    2011-07-01

    The polarization (%) of L-shell fluorescent X-rays (L?, L? and Ll) of Lu, Hf, Ta, W, Os, Pt, Au, Hg, Tl, Pb, Bi, Th and U excited by 59.54keV photons has been measured. These polarization degrees were then used to determine the alignment parameters A(2.) The Ll X-rays were found to be strongly polarized, whereas L? and L? X-rays showed less polarization. In this regard, the L?, L? and Ll groups show anisotropic spatial distributions. The results for polarization (%) as well as alignment parameters were compared with the ones available in literature. PMID:21489809

  5. Effects of Oxygen Element and Oxygen-Containing Functional Groups on Surface Wettability of Coal Dust with Various Metamorphic Degrees Based on XPS Experiment

    PubMed Central

    Zhou, Gang; Xu, Cuicui; Cheng, Weimin; Zhang, Qi; Nie, Wen

    2015-01-01

    To investigate the difference of surface oxygen element and oxygen-containing functional groups among coal dusts with different metamorphic degrees and their influence on surface wettability, a series of X-ray photoelectron spectroscopy experiments on 6 coal samples are carried out. The result demonstrates that the O/C ratio of coal surface shows an overall increasing trend compared with the result of its elements analysis. As the metamorphic degree increases, the O/C ratio on the surface gradually declines and the hydrophilic groups tend to fall off from coal surface. It could be found that different coals show different surface distributions of carboxyl and hydroxyl which are considered as the greatest promoter to the wettability of coal surface. With the change of metamorphic degree, the distribution of ether group is irregular while the carbonyl distribution keeps stable. In general, as the metamorphic degree goes higher, the content of oxygen-containing polar group tends to reduce. According to the measurement results, the contact angle is negatively related to the content of oxygen element, surface oxygen, and polar groups. In addition, compared with surface oxygen content, the content of oxygen-containing polar group serves as a more reasonable indicator of coal dust wettability. PMID:26257980

  6. Platinum group elements in a 3. 5 Ga nickel-iron occurrence: Possible evidence of a deep mantle origin

    SciTech Connect

    Tredoux, M.; Hart, R.J.; Lindsay, N.M.; Sellschop, J.P.F. ); de Wit, M.J. Lunar and Planetary Inst., Houston, TX ); Armstrong, R.A. )

    1989-01-10

    The Bon Accord (BA) Ni-Fe deposit occurs in chemically depleted ultramafic rocks of the circa 3.5 Ga Jamestown opholite complex in the Barberton greenstone belt of the Kaapvaal craton, South Africa. BA is unusual both mineralogically and chemically. It consists of a rare Ni-rich assemblage: Ni-oxide (bunsenite), -spinels (trevorite, nichromite), and -silicates (e.g., liebenbergite, the Ni end-member olivine) and their altered equivalents. NiO (average = 38%) and FeO + Fe{sub 2}O{sub 3} (average = 34%) are the major chemical constituents. The Cu and S contents are very low (both < 100 ppm), and no evidence for replacement of preexisting sulphides has been detected. BA is enriched in platinum group elements (PGE) and shows bimodal patterns on the standard PGE diagrams. Differences between the patterns are much greater for Os and Ir than for the other PGE. This observation is interpreted as being indicative of a high-temperature process (> 2000C; lower mantle). High Ni/Fe and Ni/Co ratios (relative to C-1 chondrite) suggest that BA might have been derived form siderophile-rich material that remained in the lower mantle after inefficient core formation. A model is presented wherein such a metal-silicate heterogeneity is fractionated and oxidized during ascent through the mantle in a thermal plume which originates in the lowermost mantle during formation of the Archean oceanic crust. Inclusion of such fractionated pods in the old subcontinental 'keel' of the Kaapvaal craton might constitute a potential PGE source, which could have been tapped by subsequent magmatic activity.

  7. Deletion of the P5abc Peripheral Element Accelerates Early and Late Folding Steps of the Tetrahymena Group I Ribozyme

    SciTech Connect

    Russell,R.; Tijerina, P.; Chadee, A.; Bhaskaran, H.

    2007-01-01

    The P5abc peripheral element stabilizes the Tetrahymena group I ribozyme and enhances its catalytic activity. Despite its beneficial effects on the native structure, prior studies have shown that early formation of P5abc structure during folding can slow later folding steps. Here we use a P5abc deletion variant (E{sup {Delta}P5abc}) to systematically probe the role of P5abc throughout tertiary folding. Time-resolved hydroxyl radical footprinting shows that E{sup {Delta}P5abc} forms its earliest stable tertiary structure on the millisecond time scale, {approx}5-fold faster than the wild-type ribozyme, and stable structure spreads throughout E{sup {Delta}P5abc} in seconds. Nevertheless, activity measurements show that the earliest detectable formation of native E{sup {Delta}P5abc} ribozyme is much slower ({approx}0.6 min{sup -1}), in a manner similar to that of the wild type. Also similar, only a small fraction of E{sup {Delta}P5abc} attains the native state on this time scale under standard conditions at 25 {sup o}C, whereas the remainder misfolds; footprinting experiments show that the misfolded conformer shares structural features with the long-lived misfolded conformer of the wild-type ribozyme. Thus, P5abc does not have a large overall effect on the rate-limiting step(s) along this pathway. However, once misfolded, E{sup {Delta}P5abc} refolds to the native state 80-fold faster than the wild-type ribozyme and is less accelerated by urea, indicating that P5abc stabilizes the misfolded structure relative to the less-ordered transition state for refolding. Together, the results suggest that, under these conditions, even the earliest tertiary folding intermediates of the wild-type ribozyme represent misfolded species and that P5abc is principally a liability during the tertiary folding process.

  8. Re-Os isotope and platinum group elements of a FOcal ZOne mantle source, Louisville Seamounts Chain, Pacific ocean

    NASA Astrophysics Data System (ADS)

    Tejada, Maria Luisa G.; Hanyu, Takeshi; Ishikawa, Akira; Senda, Ryoko; Suzuki, Katsuhiko; Fitton, Godfrey; Williams, Rebecca

    2015-02-01

    The Louisville Seamount Chain (LSC) is, besides the Hawaiian-Emperor Chain, one of the longest-lived hotspot traces. We report here the first Re-Os isotope and platinum group element (PGE) data for Canopus, Rigil, and Burton Guyots along the chain, which were drilled during IODP Expedition 330. The LSC basalts possess (187Os/188Os)i = 0.1245-0.1314 that are remarkably homogeneous and do not vary with age. A Re-Os isochron age of 64.9 ± 3.2 Ma was obtained for Burton seamount (the youngest of the three seamounts drilled), consistent with 40Ar-39Ar data. Isochron-derived initial 187Os/188Os ratio of 0.1272 ± 0.0008, together with data for olivines (0.1271-0.1275), are within the estimated primitive mantle values. This (187Os/188Os)i range is similar to those of Rarotonga (0.124-0.139) and Samoan shield (0.1276-0.1313) basalts and lower than those of Cook-Austral (0.136-0.155) and Hawaiian shield (0.1283-0.1578) basalts, suggesting little or no recycled component in the LSC mantle source. The PGE data of LSC basalts are distinct from those of oceanic lower crust. Variation in PGE patterns can be largely explained by different low degrees of melting under sulfide-saturated conditions of the same relatively fertile mantle source, consistent with their primitive mantle-like Os and primordial Ne isotope signatures. The PGE patterns and the low 187Os/188Os composition of LSC basalts contrast with those of Ontong Java Plateau (OJP) tholeiites. We conclude that the Re-Os isotope and PGE composition of LSC basalts reflect a relatively pure deep-sourced common mantle sampled by some ocean island basalts but is not discernible in the composition of OJP tholeiites.

  9. Biocompatibility and compressive properties of Ti-6Al-4V scaffolds having Mg element.

    PubMed

    Kalantari, Seyed Mohammad; Arabi, Hossein; Mirdamadi, Shamsodin; Mirsalehi, Seyed Ali

    2015-08-01

    Porous scaffolds of Ti-6Al-4V were produced by mixing of this alloy with different amount of magnesium (Mg) powders. The mixtures were compacted in steel die by applying uniaxial pressure of 500 MPa before sintering the compacts in sealed quartz tubes at 900 °C for 2 h. Employing Archimedes? principle and Image Tool software, the total and open volume percentages of porosities within the scaffolds were found to be in the range of 47-64% and 41-47%, respectively. XRD results of titanium before and after sintering showed that no contamination, neither oxides nor nitrides formed during processes. Compressive properties of the scaffolds were studied using an Instron machine. The observed compressive strength and Young?s module of the scaffolds were in the range of 72-132 MPa, and 37-47 GPa, respectively. Cell attachment and proliferation rate of MG-63 on porous samples were investigated. The results showed that proliferation rate increased with increasing Mg content. However no clear differences were observed between samples regarding cell attachment, so that bridges were observed in all cell gaps within the scaffolds. PMID:25955560

  10. Top decay physics at CDF and measurement of the CKM element V{sub tb}

    SciTech Connect

    LeCompte, T.J.

    1995-12-31

    Now that the top quark`s existence has been firmly established by the CDF and D0 experiments{sup 1,2)}, we begin to measure its properties. Branching fractions are of particular interest in the case of the t quark, since they probe the couplings of the top quark to gauge bosons and other quarks, and because ``the top quark is the only quark with reasonable mass``{sup 3)}. Because the top quark is the only quark with mass comparable to the electroweak scale, its decays, particularly non-standard decays, might shed some light on what makes the top quark different from lighter quarks, and the role it plays in electroweak symmetry breaking. This paper describes some recent measurements on the decay of the top quark using the CDF detector, a general purpose detector designed to study p{bar p} collisions at {radical}s=1.8 TeV; it has been described in detail elsewhere{sup 4,1)}. The analyses presented use 100-110 pb{minus}{sup 1} of data collected between 1992 and 1995 at the Fermilab TeVatron.

  11. Examining the Use of Video Study Groups for Developing Literacy Pedagogical Content Knowledge of Critical Elements of Strategy Instruction with Elementary Teachers

    ERIC Educational Resources Information Center

    Shanahan, Lynn E.; Tochelli, Andrea L.

    2014-01-01

    This collective case study explored what nine elementary teachers' video study group discussions revealed about their understanding of pedagogical content knowledge for an explicit reading strategy instruction framework, Critical Elements of Strategy Instruction (CESI). Qualitative methods were used to inductively and deductively analyze…

  12. Determination, by X-ray-fluorescence spectroscopy, of platinum-group elements, iron, and chromium in special corrosion-resistant steels

    SciTech Connect

    Eddy, B.T.; Balaes, A.M.E.; Hasty, R.A.; Farrer, H.N.

    1987-11-01

    X-ray fluorescence spectroscopy has been applied to the analysis of corrosion-resistant steels.It is known that addition of platinum group elements increases the corrosion resistance of metals and alloys; however, such metals are costly. Therefore x-ray fluorescence analysis, a nondestructive technique was applied in the present study.(AIP)

  13. Group V Phospholipase A2-mediated Oleic Acid Mobilization in Lipopolysaccharide-stimulated P388D1 Macrophages*

    E-print Network

    Dennis, Edward A.

    Group V Phospholipase A2-mediated Oleic Acid Mobilization in Lipopolysaccharide-stimulated P388D1-activated cells are prelabeled with [3 H]oleic acid (OA), they also mobilize and release OA to the extracel- lular show that the activated cells do release measurable amounts of oleic acid (OA), that this release

  14. 76 FR 45248 - PJM Interconnection, L.L.C., PJM Power Providers Group v. PJM Interconnection, L.L.C...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-28

    ... Energy Regulatory Commission PJM Interconnection, L.L.C., PJM Power Providers Group v. PJM Interconnection, L.L.C.; Supplemental Notice of Staff Technical Conference On June 13, 2011, the Commission issued... Resources Services, Inc., Maryland Public Service Commission, Monitoring Analytics, L.L.C., National...

  15. Electrical and optical characterization of Group III-V heterostructures with emphasis on terahertz devices

    NASA Astrophysics Data System (ADS)

    Weerasekara, Aruna B.

    Electrical and optical characterizations of heterostructures and thin films based on group III-V compound semiconductors are presented. Optical properties of GaMnN thin films grown by Metalorganic Chemical Vapor Deposition (MOCVD) on GaN/Sapphire templates were investigated using IR reflection spectroscopy. Experimental reflection spectra were fitted using a non-linear fitting algorithm, and the high frequency dielectric constant (epsiloninfinity), optical phonon frequencies of E1TO and E1 LO, and their oscillator strengths (S) and broadening constants (Gamma) were obtained for GaMnN thin films with different Mn fraction. The high frequency dielectric constant (epsiloninfinity) of InN thin films grown by the high pressure chemical vapor deposition (HPCVD) method was also investigated by IR reflection spectroscopy and the average was found to vary between 7.0--8.6. The mobility of free carriers in InN thin films was calculated using the damping constant of the plasma oscillator. The terahertz detection capability of n-type GaAs/AlGaAs Heterojunction Interfacial Workfunction Internal Photoemission (HEIWIP) structures was demonstrated. A threshold frequency (fc) of 3.2 THz (93 mum) with a peak responsivity of 6.5 A/W at 7.1 THz was obtained using a 0.7 mum thick 1x1018 cm-3 n-type doped GaAs emitter layer and a 1 mum thick undoped Al0.04Ga0.96As barrier layer. Using n-type doped GaAs emitter layers, the possibility of obtaining small workfunctions (Delta) required for terahertz detectors has been successfully demonstrated. In addition, the possibility of using GaN (GaMnN) and InN materials for terahertz detection was investigated and a possible GaN base terahertz detector design is presented. The non-linear behavior of the Inter Pulse Time Intervals (IPTI) of neuron-like electric pulses triggered externally in a GaAs/InGaAs Multi Quantum Well (MQW) structure at low temperature (˜ 10 K) was investigated. It was found that a grouping behavior of IPTIs exists at slow triggering pulse rates. Furthermore, the calculated correlation dimension reveals that the dimensionality of the system is higher than the average dimension found in most of the natural systems. Finally, an investigation of terahertz radiation effect on biological system is reported. Index words. Infrared, Detectors, Terahertz, Optical Phonon, Plasmon, Heterojunction, Homojunction, Free carrier absorption, Quantum efficiency, Responsivity, Dark current, Arrhenius, Absorption coefficient, Dielectric function, High frequency dielectric constant, Plasma frequency, Neuron-like pulses, Negative differential resistance, Correlation dimension, Embedding dimension, Return maps, Bifurcation, and Power spectrum.

  16. SEPARATING INVARIANTS AND FINITE REFLECTION GROUPS

    E-print Network

    Abrahams, I. David

    SEPARATING INVARIANTS AND FINITE REFLECTION GROUPS EMILIE DUFRESNE Abstract. A separating algebra to the presence of reflections, elements of G fixing a subspace of codimension 1 in V : 1 #12;2 EMILIE DUFRESNE

  17. Platinum Group Elements (PGE) geochemistry of komatiites and boninites from Dharwar Craton, India: Implications for mantle melting processes

    NASA Astrophysics Data System (ADS)

    Saha, Abhishek; Manikyamba, C.; Santosh, M.; Ganguly, Sohini; Khelen, Arubam C.; Subramanyam, K. S. V.

    2015-06-01

    High MgO volcanic rocks having elevated concentrations of Ni and Cr are potential hosts for platinum group elements (PGE) owing to their primitive mantle origin and eruption at high temperatures. Though their higher PGE abundance is economically significant in mineral exploration studies, their lower concentrations are also valuable geochemical tools to evaluate petrogenetic processes. In this paper an attempt has been made to evaluate the PGE geochemistry of high MgO volcanic rocks from two greenstone belts of western and eastern Dharwar Craton and to discuss different mantle processes operative at diverse geodynamic settings during the Neoarchean time. The Bababudan greenstone belt of western and Gadwal greenstone belt of eastern Dharwar Cratons are dominantly composed of high MgO volcanic rocks which, based on distinct geochemical characteristics, have been identified as komatiites and boninites respectively. The Bababudan komatiites are essentially composed of olivine and clinopyroxene with rare plagioclase tending towards komatiitic basalts. The Gadwal boninites contain clinopyroxene, recrystallized hornblende with minor orthopyroxene, plagioclase and sulphide minerals. The Bababudan komatiites are Al-undepleted type (Al2O3/TiO2 = 23-59) with distinctly high MgO (27.4-35.8 wt.%), Ni (509-1066 ppm) and Cr (136-3036 ppm) contents. These rocks have low ?PGE (9-42 ppb) contents with 0.2-2.4 ppb Iridium (Ir), 0.2-1.4 ppb Osmium (Os) and 0.4-4.4 ppb Ruthenium (Ru) among Iridium group PGE (IPGE); and 1.4-16.2 ppb Platinum (Pt), 2.8-19 ppb Palladium (Pd) and 0.2-9.8 ppb Rhodium (Rh) among Platinum group PGE (PPGE). The Gadwal boninites are high-Ca boninites with CaO/Al2O3 ratios varying between 0.8 and 1.0, with 12-24 wt.% MgO, 821-1168 ppm Ni and 2307-2765 ppm Cr. They show higher concentration of total PGE (82-207 ppb) with Pt concentration ranging from 13 to 19 ppb, Pd between 65 and 180 ppb and Rh in the range of 1.4-3 ppb compared to the Bababudan komatiites. Ir, Os and Ru concentrations range from 0.6 to 2.2 ppb, 0.2 to 0.6 ppb and 1.4 to 2.6 ppb respectively in IPGE. The PGE abundances in Bababudan komatiites were controlled by olivine fractionation whereas that in Gadwal boninites were influenced by fractionation of chromite and sulphides. The Al-undepleted Bababudan komatiites are characterized by low CaO/Al2O3, (Gd/Yb)N, (La/Yb)N, with positive Zr, Hf, Ti anomalies and high Cu/Pd, Pd/Ir ratios at low Pd concentrations suggesting the derivation of parent magma by high degrees (>30%) partial melting of mantle under anhydrous conditions at shallow depth with garnet as a residual phase in the mantle restite. The komatiites are geochemically analogous to Al-undepleted Munro type komatiites and their PGE compositions are consistent with Alexo and Gorgona komatiites. The S-undersaturated character of Bababudan komatiites is attributed to decompression and assimilation of lower crustal materials during magma ascent and emplacement. In contrast, the higher Al2O3/TiO2, lower (Gd/Yb)N, for Gadwal boninites in combination with negative Nb, Zr, Hf, Ti anomalies and lower Cu/Pd at relatively higher Pd/Ir and Pd concentrations reflect high degree melting of refractory mantle wedge under hydrous conditions in an intraoceanic subduction zone setting. Higher Pd/Ir ratios and S-undersaturation of these boninites conform to influx of fluids derived by dehydration of subducted slab resulting into high fluid pressure and metasomatism of mantle wedge.

  18. Theoretical predictions of properties and volatility of chlorides and oxychlorides of group-4 elements. I. Electronic structures and properties of MCl{sub 4} and MOCl{sub 2} (M = Ti, Zr, Hf, and Rf)

    SciTech Connect

    Pershina, V.; Borschevsky, A.; Iliaš, M.

    2014-08-14

    Relativistic, infinite order exact two-component, density functional theory electronic structure calculations were performed for MCl{sub 4} and MOCl{sub 2} of group-4 elements Ti, Zr, Hf, and element 104, Rf, with the aim to predict their behaviour in gas-phase chromatography experiments. RfCl{sub 4} and RfOCl{sub 2} were shown to be less stable than their lighter homologs in the group, tetrachlorides and oxychlorides of Zr and Hf, respectively. The oxychlorides turned out to be stable as a bent structure, though the stabilization energy with respect to the flat one (C{sub 2v}) is very small. The trend in the formation of the tetrachlorides from the oxychlorides in group 4 is shown to be Zr < Hf < Rf, while the one in the formation of the oxychlorides from the chlorides is opposite. All the calculated properties are used to estimate adsorption energy of these species on various surfaces in order to interpret results of gas-phase chromatography experiments, as is shown in Paper II.

  19. Sniffing for Clues to the Dinosaurs Demise: Measurement of Osmium Isotope Compositions and Platinum Group Element Abundances in Volcanic Emissions

    NASA Astrophysics Data System (ADS)

    Sims, K. W.; Peucker-Ehrenbrink, B.; Mather, T.; Pyle, D.; Martin, R.; Gauthier, P.; Aiuppa, A.

    2005-12-01

    Platinum Group Elements (PGE: Os, Ir, Rh, Ru, Pt, Pd) and osmium isotopes measured in marine and terrestrial sediment, snow and ice records are important paleo-tracers of riverine, hydrothermal, extraterrestrial, volcanic and anthropogenic inputs into the global surficial environment. For instance, the marine Os isotope record across the Cretaceous-Tertiary Boundary (KTB) indicates that the onset of the main phase of Deccan volcanism and the transient late Maastrichtian warming preceded the large extraterrestrial impact and the related KTB mass extinction by several hundred thousand years [Ravizza and Peucker-Ehrenbrink, 2003]. Distinguishing extraterrestrial from volcanic PGE sources has been difficult due to the similarity in Os isotopic compositions, complex PGE fractionations, and our lack of knowledge of the Os isotopic composition and PGE abundances in volcanic aerosols. These difficulties have fueled vigorous debate about extraterrestrial vs. volcanic triggers of mass extinctions in the geologic record. To assess the volcanic contribution to the global Re-Os-PGE cycle we have initiated a study of Os isotopic compositions and PGE abundances in volcanic emissions from volcanoes around the globe. Here we report preliminary data on PGE abundances and Os isotopes measured in gas and aerosol filter samples from Vulcan Masaya, Nicaragua and Mt Etna, Italy. Samples were analyzed by ID-ICPMS (ThermoFinnigan ELEMENT 2 and NEPTUNE) at the Woods Hole Oceanographic Institution. Osmium isotope compositions of the filters are unradiogenic (0.1272 to 0.187). Osmium concentrations range from 28 to 97 pg/cubic meter and are 3-4 orders of magnitude lower than those measured by Krahenbuhl et al. [1992] during the spring 1984 eruption of Mauna Loa just after the lava fountaining phase. Normalized PGE abundance patterns are fractionated relative to carbonaceous chondrites and two important features distinguish the pattern from other important PGE sources: 1) Os/Ir is much higher than that of the continental crust, the mantle and extraterrestrial matter; and 2) Pt/Pd is much lower than that of the continental crust, mantle, extraterrestrial matter and catalytic converters. If these PGE patterns from Masaya and Etna are typical of volcanic emissions worldwide they indicate that volcanic emission PGE patterns are distinct from the globally integrated KTB patterns [Tredoux et al. 1989; Evans et al., 1993] and that a volcanic source is not the cause of the elevated PGE abundances across the KTB. The PGE pattern of volcanic emissions is also different from catalytic converters enabling us to distinguish between volcanic sources and contamination from catalytic converters in places such as the Greenland Ice sheet [Barbante et al., 2001]. While these data have important implications for understanding the contribution of volcanic emissions to the global Re-Os-PGE cycles they need to be augmented with further analyses from other volcanoes.

  20. Platinum-group element abundance and distribution in chromite deposits of the Acoje Block, Zambales Ophiolite Complex, Philippines

    USGS Publications Warehouse

    Bacuta, G.C., Jr.; Kay, R.W.; Gibbs, A.K.; Lipin, B.R.

    1990-01-01

    Platinum-group elements (PGE) occur in ore-grade concentration in some of the chromite deposits related to the ultramafic section of the Acoje Block of the Zambales Ophiolite Complex. The deposits are of three types: Type 1 - associated with cumulate peridotites at the base of the crust; Type 2 - in dunite pods from the top 1 km of mantle harzburgite; and Type 3 - like Type 2, but in deeper levels of the harzburgite. Most of the deposites have chromite compositions that are high in Cr with Cr/(Cr + Al) (expressed as chromium index, Cr#) > 0.6; high-Al (Cr# Pd, thought to be characteristic of PGE-barren deposits) and positive slope (Ir < Pd, characteristic of PGE-rich deposits). Iridium, Ru and Os commonly occur as micron-size laurite (sulfide) inclusions in unfractured chromite. Laurite and native Os are also found as inclusions in interstitial sulfides. Platinum and Pd occur as alloy inclusions (and possibly as solid solution) in interstitial Ni-Cu sulfides and as tellurobismuthides in serpentine and altered sulfides. Variability of PGE distribution may be explained by alteration, crystal fractionation or partial melting processes. Alteration and metamorphism were ruled out, because PGE contents do not correlate with degree of serpentinization or the abundance and type (hydroxyl versus non-hydroxyl) of silicate inclusions in chromite. Preliminary Os isotopic data do not support crustal contamination as a source of the PGEs in the Acoje deposits. The anomalous PGE concentrations in Type 1 high-Cr chromite deposits are attributed to two stages of enrichment: an early enrichment of their mantle source from previous melting events and a later stage of sulfide segregation accompanying chromite crystallization. High-Al chromite deposits which crystallized from basalts derived from relatively low degrees of melting owe their low PGE content to partitioning of PGEs in sulfides and alloys that remain in the mantle. High-Cr deposits crystallized from melts that were previously enriched with PGEs during early melting events of their mantle source; Pt and Pd ore concentrations (ppm levels) are attained by segregation of magmatic sulfides. The Acoje deposits indicate that ophiolites are a potential economic source of the PGEs. ?? 1990.

  1. Ni, Cu, Au, and platinum-group element contents of sulphides associated with intraplate magmatism: A synthesis

    USGS Publications Warehouse

    Barnes, S.-J.; Zientek, M.L.; Severson, M.J.

    1997-01-01

    The tectonic setting of intraplate magmas, typically a plume intersecting a rift, is ideal for the development of Ni - Cu - platinum-group element-bearing sulphides. The plume transports metal-rich magmas close to the mantle - crust boundary. The interaction of the rift and plume permits rapid transport of the magma into the crust, thus ensuring that no sulphides are lost from the magma en route to the crust. The rift may contain sediments which could provide the sulphur necessary to bring about sulphide saturation in the magmas. The plume provides large volumes of mafic magma; thus any sulphides that form can collect metals from a large volume of magma and consequently the sulphides will be metal rich. The large volume of magma provides sufficient heat to release large quantities of S from the crust, thus providing sufficient S to form a large sulphide deposit. The composition of the sulphides varies on a number of scales: (i) there is a variation between geographic areas, in which sulphides from the Noril'sk - Talnakh area are the richest in metals and those from the Muskox intrusion are poorest in metals; (ii) there is a variation between textural types of sulphides, in which disseminated sulphides are generally richer in metals than the associated massive and matrix sulphides; and (iii) the massive and matrix sulphides show a much wider range of compositions than the disseminated sulphides, and on the basis of their Ni/Cu ratio the massive and matrix sulphides can be divided into Cu rich and Fe rich. The Cu-rich sulphides are also enriched in Pt, Pd, and Au; in contrast, the Fe-rich sulphides are enriched in Fe, Os, Ir, Ru, and Rh. Nickel concentrations are similar in both. Differences in the composition between the sulphides from different areas may be attributed to a combination of differences in composition of the silicate magma from which the sulphides segregated and differences in the ratio of silicate to sulphide liquid (R factors). The higher metal content of the disseminated sulphides relative to the massive and matrix sulphides may be due to the fact that the disseminated sulphides equilibrated with a larger volume of magma than massive and matrix sulphides. The difference in composition between the Cu- and Fe-rich sulphides may be the result of the fractional crystallization of monosulphide solid solution from a sulphide liquid, with the Cu-rich sulphides representing the liquid and the Fe-rich sulphides representing the cumulate.

  2. Positive anomaly in platinum group elements and the presence of shocked diamonds: Two question marks at the Younger Dryas

    NASA Astrophysics Data System (ADS)

    Claeys, P. F.; Schryvers, D.; Tian, H.; Goderis, S.

    2009-12-01

    Recently, a large size impact was proposed as the cause of the global changes taking place at the Younger Dryas (YD) some 12,9 kyr ago. Impact evidence was reported in a C-rich black layer of broad geographic distribution. The impact markers consist of a large anomaly in the concentration of platinum group elements (PGE) and the presence of nanodiamonds, in particular lonsdaleite, which hexagonal structure is believed to be of shock origin. The impact is proposed to have occurred on the North American continent. A crater large enough (> 150 km) to induce a mass extinction some ~12.9 ka ago, formed in a geologically well-known area, is unlikely to have escaped detection. Therefore, an alternative hypothesis is that a cometary projectile exploded fully within the atmosphere spreading PGE and shock formed diamonds, without any target rock contribution, all around the Northern hemisphere. So far, PGE measurements failed to reproduce the elevated (> ppb) concentrations reported previously at Younger Dryas sites containing the black layer. In Lommel (Belgium) where the first study detected up to 117 ppb Ir, the Ir concentration is below the detection limit of the method (NiS fire assay + ICP-MS) used (0.06 ppb). At all sites analyzed the PGE pattern is typical of that of the continental crust. In several craters (Popigai, Ries) or at the KT boundary nanodiamonds have been reported associated with shocked materials. Several types of carbon components occur in the black layer of the Lommel section such as i) flakes reaching up to 1 µm, ii) nano particles of cubic diamond, 1 to 10 nm in size and iii) larger carbon onion-ring structures, which core can act as a nanoscopic pressure cell leading to the formation of nanodiamond by self- compression. The Lommel nanodiamonds present in the Younger Dryas layer do resemble nanodiamonds found in carbon spherules of unknown origin previously reported in top soil from several localities in Belgium and Germany. The C stable isotopic signature measured in the C-rich black layer is clearly produced by organic matter of terrestrial origin (-29‰).

  3. Molecular structure and intermediate phases in group-V binary chalcogenide glasses

    NASA Astrophysics Data System (ADS)

    Georgiev, Daniel Georgiev

    Chalcogenide glasses offer unique opportunities for basic science and technological applications. The physical properties of such network-forming glasses, including the glass-forming tendency, are intimately connected to global connectivity of their backbones. In particular, the elastic behavior of glasses leads to the existence of three distinct phases that appears to be generic in network forming systems. Weakly cross-linked networks are mechanically soft and form floppy phases. Optimally cross-linked networks lead to stress-free or self-organized networks, and are identified with intermediate phases. Strongly cross-linked networks are mechanically stiff and usually form part of stressed-rigid phases. The floppy-intermediate and stressed-rigid classification of the group V chalcogenides is recognized in this work for the first time. The glass systems examined include P-Se, As-Se, and As-S. Thermally reversing windows (glass compositions wherein Tg become almost completely reversing) are observed in the three binary glass systems using temperature-Modulated Differential Scanning Calorimetry (MDSC), and are identified with the opening of (non-mean-field) intermediate phases . The molecular structure of these glasses is studied by Raman scattering, MDSC and 31P NMR, and the local structures responsible for intermediate phases are identified with assistance from constraint counting procedures. Raman scattering and Nuclear Magnetic Resonance (NMR) results on P-Se glasses provide compelling evidence for existence of four-fold coordinated phosphorous species that are bonded to three bridging and one terminal selenium, Se = P(Se1/2)3. The structure results provide a basis to quantitatively understand compositional trends in Tg in the stochastic agglomeration limit. The existence of analog four-fold coordinated As species is suggested by MDSC experiments on As-Se glasses. Our experimental results also show that stressed-rigid phases in the examined glasses are usually phase separated on a molecular level. Phase separation initiates near the stoichiometric composition, As2S3, and grows as the As content, x, of binary As xS1-x glasses exceeds 0.38. Similar behavior has been observed in As-Se and P-Se glasses. A new understanding of global maxima in glass transition temperatures near stoichiometric compositions has emerged. These maxima are the result of a decrease in network connectivity as the backbone nano-scale phase separates.

  4. The coupling of thermochemistry and phase diagrams for group III-V semiconductor systems. Final report

    SciTech Connect

    Anderson, T.J.

    1998-07-21

    The project was directed at linking the thermochemical properties of III-V compound semiconductors systems with the reported phase diagrams. The solid-liquid phase equilibrium problem was formulated and three approaches to calculating the reduced standard state chemical potential were identified and values were calculated. In addition, thermochemical values for critical properties were measured using solid state electrochemical techniques. These values, along with the standard state chemical potentials and other available thermochemical and phase diagram data, were combined with a critical assessment of selected III-V systems. This work was culminated with a comprehensive assessment of all the III-V binary systems. A novel aspect of the experimental part of this project was the demonstration of the use of a liquid encapsulate to measure component activities by a solid state emf technique in liquid III-V systems that exhibit high vapor pressures at the measurement temperature.

  5. Experiments and finite element simulations on micro-milling of Ti6Al4V alloy with uncoated and cBN coated micro-tools

    E-print Network

    Ozel, Tugrul

    Experiments and finite element simulations on micro-milling of Ti­6Al­4V alloy with uncoated and c. Introduction The micro-milling process possesses several advantages such as ease of use, process flexibility accuracy and precision [1,2]. Micro-milling is often defined as end-milling with micro- tools in diameter

  6. Effect of isothermal forging on microstructure and fatigue behavior of blended elemental Ti-6Al-4V powder compacts

    NASA Astrophysics Data System (ADS)

    Weiss, I.; Eylon, D.; Toaz, M. W.; Froes, F. H.

    1986-03-01

    The effect of isothermal hot forging (IHF) on microstructure, pore closure, and tensile and fatigue properties of Ti-6A1-4V blended elemental cold pressed and sintered powder compacts was investigated. Two types of sponge fines were used: (a) high chloride produced by the Hunter sodium reduction process (HP) and (b) low chloride produced by the electrolytic process (EP). The as-sintered HP compacts were 99 pct dense while the EP compacts were only 92 pct dense. All sintered preforms were isothermally hot forged below the beta transus temperature and reached almost full density. The microstructure of the HP forged compacts consisted of fine equiaxed alpha, while the EP forged compacts exhibited a coarse lenticular alpha structure after 30 pct reduction and a partially recrystallized structure after 68 pct reduction. It was found that EP compacts forged to a 30 pct reduction exhibited a low fatigue limit of 172 MPa (25 ksi), since the lenticular alpha morphology and the residual porosity resulted in premature fatigue crack initiation. On the other hand, a higher fatigue strength of 485 MPa (70 ksi) was obtained for EP compacts forged to a 78 pct reduction due to the mixed equiaxed/lenticular alpha morphology as well as removal of stress concentration features such as interparticle pore interfaces.

  7. Effect of isothermal forging on microstructure and fatigue behavior of blended elemental Ti-6Al-4V powder compacts

    SciTech Connect

    Weiss, I.; Eylon, D.; Toaz, M.W.; Froes, F.H.

    1986-03-01

    The effect of isothermal hot forging (IHF) on microstructure, pore closure, and tensile and fatigue properties of Ti-6Al-4V blended elemental cold pressed and sintered powder compacts was investigated. Two types of sponge fines were used: (1) chloride produced by the Hunter sodium reduction process (HP) and (2) low chloride produced by the electrolytic process (EP). The as-sintered HP compacts were 99 pct dense while the EP compacts were only 92 pct dense. All sintered preforms were isothermally hot forged below the beta transus temperature and reacted almost full density. The microstructure of the HP forged compacts consisted of fine equiaxed alpha, while the EP forged compacts exhibited a coarse lenticular alpha structure after 30 pct reduction and a partially recrystallized structure after 68 pct reduction. It was found that EP compacts forged to a 30 pct reduction exhibited a low fatigue limit of 172 MPa (25 ksi), since the lenticular alpha morphology and the residual porosity resulted in premature fatigue crack initiation. On the other hand, a higher fatigue strength of 485 MPa (70 ksi) was obtained for EP compacts forged to a 78 pct reduction due to the mixed equiaxed/lenticular alpha morphology as well as removal of stress concentration features such as interparticle pore interfaces. 26 references.

  8. Les Houches Physics at TeV Colliders 2005 Beyond the Standard Model Working Group: Summary Report

    SciTech Connect

    Allanach, B.C.; Grojean, C.; Skands, P.; Accomando, E.; Azuelos, G.; Baer, H.; Balazs, C.; Belanger, G.; Benakli, K.; Boudjema, F.; Brelier, B.; Bunichev, V.; Cacciapaglia, G.; Carena, M.; Choudhury, D.; Delsart, P.-A.; De Sanctis, U.; Desch, K.; Dobrescu, B.A.; Dudko, L.; El Kacimi, M.; /Saclay, SPhT /CERN /Fermilab /INFN, Turin /Turin U. /Montreal U. /TRIUMF /Florida State U. /Argonne /Annecy, LAPTH /Paris, LPTHE /Moscow State U. /Cornell U., CIHEP /Delhi U. /Milan U. /INFN, Milan /Freiburg U. /Cadi Ayyad U., Marrakech /Orsay, LPT /Oslo U. /Lancaster U.

    2006-03-17

    The work contained herein constitutes a report of the ''Beyond the Standard Model'' working group for the Workshop ''Physics at TeV Colliders'', Les Houches, France, 2-20 May, 2005. We present reviews of current topics as well as original research carried out for the workshop. Supersymmetric and non-supersymmetric models are studied, as well as computational tools designed in order to facilitate their phenomenology.

  9. CLASSICAL GROUPS FROM A NON-CIJ\\SSICAL v:n.';WPOIN'l!_ ...____ ..........-_.1,. ._-__.__"__---"' ... -. . -...__

    E-print Network

    Kantor, William M.

    ; to the Mathematics. . . Institute at Oxford University for inviting me. to give these lectures; and to Joyce 1 groups Root group geometry #12;(A') The ,s.£.e~la1. line~r gro~..1p ,. SL!.tb..fields, vectors

  10. Solid-state 207pb nmr studies of lead-group 16 and mixedtransition-metal-lead-group 16 element-containing materials

    SciTech Connect

    Van Bramer, S.E.; Glatfelter, A.; Bai, S.; Dybowksi, C.; GNeue,G.; Perry, D.L.

    2005-08-26

    207Pb solid-state NMR studies have been conducted on binarylead-group 16 and mixed transition-metal/lead group 16 materials,correlating the NMR chemical shifts of the materials with theirstructures. The experimental results show that the 207Pb chemical shiftsare strongly influenced by the local electronic structure. Data arereported for lead selenide, lead selenate, calcium plumbate, strontiumplumbite, barium plumbite, lead borate, lead zirconate, lead tungstate,lead meta-tantalate, lead niobate, lead molybdate, lead meta-vanadate,lead sulfite, and lead sulfate.

  11. Nucleolar introns from Physarum flavicomum contain insertion elements that may explain how mobile group I introns gained their open reading frames.

    PubMed Central

    Vader, A; Naess, J; Haugli, K; Haugli, F; Johansen, S

    1994-01-01

    Comparison of two group I intron sequences in the nucleolar genome of the myxomycete Physarum flavicomum to their homologs in the closely related Physarum polycephalum revealed insertion-like elements. One of the insertion-like elements consists of two repetitive sequence motifs of 11 and 101 bp in five and three copies, respectively. The smaller motif, which flanks the larger, resembles a target duplication and indicates a relationship to transposons or retroelements. The insertion-like elements are found in the peripheral loops of the RNA structure; the positions occupied by the ORFs of mobile nucleolar group I introns. The P. flavicomum introns are 1184 and 637 bp in size, located in the large subunit ribosomal RNA gene, and can be folded into group I intron structures at the RNA level. However, the intron 2s from both P. flavicomum and P. polycephalum contain an unusual core region that lacks the P8 segment. None of the introns are able to self-splice in vitro. Southern analysis of different isolates indicates that the introns are not optional in myxomycetes. Images PMID:7984404

  12. The use of cation exchange matrix separation coupled with ICP-MS to directly determine platinum group element (PGE) and other trace element emissions from passenger cars equipped with diesel particulate filters (DPF).

    PubMed

    Cairns, Warren R L; De Boni, Antonella; Cozzi, Giulio; Asti, Massimo; Borla, Edoardo Merlone; Parussa, Flavio; Moretto, Ezio; Cescon, Paolo; Boutron, Claude; Gabrieli, Jacopo; Barbante, Carlo

    2011-03-01

    Inductively coupled plasma-mass spectrometry coupled with cation exchange matrix separation has been optimised for the direct determination of platinum group element (PGE) and trace element emissions from a diesel engine car. After matrix separation method detection limits of 1.6 ng g(-1) for Pd, 0.4 ng g(-1) for Rh and 4.3 ng g(-1) for Pt were achieved, the method was validated against the certified reference material BCR 723, urban road dust. The test vehicle was fitted with new and aged catalytic converters with and without diesel particulate filters (DPF). Samples were collected after three consecutive New European Driving Cycle (NEDC) of the particulate and "soluble" phases using a home-made sampler optimised for trace element analysis. Emission factors for the PGEs ranged from 0.021 ng km(-1) for Rh to 70.5 ng km(-1) for Pt; when a DPF was fitted, the emission factors for the PGEs actually used in the catalysts dropped by up to 97% (for Pt). Trace element emission factors were found to drop by a maximum of 92% for Ni to a minimum of 18% for Y when a DPF was fitted; a new DPF was also found to cause a reduction of up to 86% in the emission of particulate matter. PMID:21210274

  13. Les Houches 2013: Physics at TeV Colliders: Standard Model Working Group Report

    E-print Network

    Butterworth, J; Dittmaier, S; de Florian, D; Glover, N; Hamilton, K; Huston, J; Kado, M; Korytov, A; Krauss, F; Soyez, G; Andersen, J R; Badger, S; Barzè, L; Bellm, J; Bernlochner, F U; Buckley, A; Butterworth, J; Chanon, N; Chiesa, M; Cooper-Sarkar, A; Cieri, L; Cullen, G; van Deurzen, H; Forte, S; Frederix, R; Fuks, B; Gao, J; Garzelli, M V; Gehrmann, T; Gerwick, E; Gieseke, S; Gillberg, D; Glover, E W N; Greiner, N; Hapola, T; Hartanto, H B; Heinrich, G; Huss, A; Jäger, B; Kardos, A; Klein, U; Kruse, A; Lönnblad, L; Luisoni, G; Maître, Daniel; Mastrolia, P; Mattelaer, O; Mazzitelli, J; Mirabella, E; Monni, P; Montagna, G; Moretti, M; Nadolsky, P; Nason, P; Nicrosini, O; Oleari, C; Ossola, G; Padhi, S; Peraro, T; Piccinini, F; Plätzer, S; Prestel, S; Pumplin, J; Rabbertz, K; Radescu, Voica; Reina, L; Reuschle, C; Rojo, J; Schönherr, M; Smillie, J M; von Soden-Fraunhofen, J F; Thorne, R; Tramontano, F; Trocsanyi, Z; Wackeroth, D; Winter, J; Yuan, C-P; Yundin, V; Zapp, K

    2014-01-01

    This Report summarizes the proceedings of the 2013 Les Houches workshop on Physics at TeV Colliders. Session 1 dealt primarily with (1) the techniques for calculating standard model multi-leg NLO and NNLO QCD and NLO EW cross sections and (2) the comparison of those cross sections with LHC data from Run 1, and projections for future measurements in Run 2.

  14. Photoionization of As sub 2 and As sub 4 : Implications for group V clusters

    SciTech Connect

    Yoo, R.K.; Ruscic, B.; Berkowitz, J. )

    1992-05-01

    The vacuum ultraviolet photoionization mass spectrum of As{sub 4} is presented, from the ionization threshold to 600 A. The apparent adiabatic ionization potential is {le}8.49 eV, but the true value may be significantly lower. Three broad autoionization features are observed, probably comprising members of a Rydberg series converging to the {ital {tilde B}} {sup 2}{ital A}{sub 1} state of As{sup +}{sub 4}. The first fragment, As{sup +}{sub 3}, has an appearance potential (0 K) of 11.23{plus minus}0.05 eV, from which we extract {Delta}{ital H}{sup 0}{sub {ital f}{sub 0}}(As{sup +}{sub 3}){le}228.7{plus minus}1.3 kcal/mol. The photoion yield curve of As{sup +}{sub 2}(As{sub 2}) is obtained under conditions where As{sub 2} is dominant in the vapor. The adiabatic ionization potential is 9.69{plus minus}0.02 eV. Two prominent autoionizing Rydberg series are observed, converging to the {ital A} {sup 2}{Sigma}{sup +}{sub {ital g}} state of As{sup +}{sub 2}, with an ionization potential of 10.238{plus minus}0.002 eV. At higher energy, three members of a window resonance series can be seen, converging to the {ital B} {sup 2}{Sigma}{sup +}{sub {ital u}} state of As{sup +}{sub 2}, with an ionization potential of 15.37 eV. From an upper limit to the partial pressure of As{sub 3}, equilibrium conditions, and assuming a triangular As{sub 3}, we deduce {Delta}{ital H}{sup 0}{sub {ital f}{sub 0}}(As{sub 3}){ge}60.0 kcal/mol; other criteria suggest {Delta}{ital H}{sup 0}{sub {ital f}{sub 0}}(As{sub 3}){congruent}63 kcal/mol. Consequently, the adiabatic ionization potential of As{sub 3} is {lt}7.32 eV, and probably {le}7.19 eV. Several implications are drawn, relevant to recent studies of antimony and bismuth clusters.

  15. Publications of A.S. Rapinchuk 1. Algebraic groups and number theory (monograph, 656p.) (with V.P.Platonov). Moscow,

    E-print Network

    and class groups of algebraic groups (with A.A. Bondarenko and V.P. Platonov), Math. USSR-Izvestija 14.A. Bondarenko and V.P. Platonov), Math. USSR-Izvestija 16(1981), No. 2, 357-372. MR 82i:20039. 6. On Platonov and algebraic groups, Math. USSR-Izvestija 19(1982), No. 1, 79-93. MR 83j:10023. 8. Multiplicative structure

  16. New clues on outburst mechanisms and improved spectroscopic elements of the black hole binary V4641 Sagittarii*

    NASA Astrophysics Data System (ADS)

    Lindstrøm, C.; Griffin, J.; Kiss, L. L.; Uemura, M.; Derekas, A.; Mészáros, Sz.; Székely, P.

    2005-11-01

    We present spectroscopic observations of the black hole binary V4641 Sagittarii, obtained between 2004 July 4 and 2005 March 28, which cover the minor outburst of the star in early 2004 July and quiescence variations on 19 nights scattered over six months. During the outburst, the star peaked approximately 3 mag brighter than usual, and our spectra were dominated by broad hydrogen, helium and iron emission lines. The very first spectra showed P Cygni profiles, which disappeared within a few hours, indicating rapid changes in matter ejection. The H? line had multiple components, one being a broad blueshifted wing exceeding 5000 km s-1. During a simultaneously observed 10-min photometric flare up, the equivalent width of the H? line temporarily decreased, implying that it was a flare of the continuum. The overall spectral appearance was similar to that observed in the 1999 September active phase, which suggests that similar mass-ejection processes were associated with both eruptions. In quiescence, the spectra were those of the early-type secondary star showing its orbital motion around the primary. By measuring cross-correlation radial velocities, we give an improved set of spectroscopic elements. Whereas we measure the same velocity amplitude (K2= 211.3 +/- 1.0 km s-1), within errors, as Orosz et al., our centre-of-mass velocity (?= 72.7 +/- 3.3 km s-1) differs significantly from the previously published value (107.4 +/- 2.9 km s-1). However, we find evidence that the difference is caused by a systematic error in data reduction in the previous study, rather than by gravitational effects of an invisible third component.

  17. Chemo-dynamical evolution model: Enrichment of r-process elements in the Local Group dwarf galaxies

    NASA Astrophysics Data System (ADS)

    Hirai, Yutaka; Ishimaru, Yuhri; Saitoh, Takayuki R.; Fujii, Michiko S.; Hidaka, Jun; Kajino, Toshitaka

    2015-08-01

    Enrichment of the r-process elements is expected to provide a critical clue to understand the formation history of galactic halos. Recent astronomical high dispersion observations of metal-poor stars have shown large dispersions in relative abundance ratios of r-process elements such as [Eu/Fe] in stars with [Fe/H] < -2.5. Astrophysical site(s) of r-process has, however, not been identified yet. Promising site(s) of r-process are core-collapse supernovae (CCSNe) and neutron-star mergers (NSMs). Recent nucleosynthesis studies have shown that r-process elements heavier than 110 of mass number are difficult to synthesize by CCSNe. On the other hand, several studies reported that NSMs can synthesize these elements due to their environment of low electron fraction. Previous chemical evolution model (e.g., Argast et al. 2004) of the Milky Way (MW) halo without dynamical evolution pointed out that the NSMs are difficult to reproduce observed dispersion in [Eu/Fe] vs. [Fe/H] due to their low rate 10-6 - 10-3 yr-1 for a MW size galaxy and the long delay time, t ? 100 Myr. In the present study, we carry out numerical simulations of galactic chemo-dynamical evolution using an N-body/smoothed particle hydrodynamics code, ASURA. We construct detailed chemo-dynamical evolution model for dwarf spheroidal galaxies (dSphs) assuming that the NSMs are the major source of the r-process elements. Our models successfully reproduce the observed dispersion in [Eu/Fe] vs. [Fe/H] if we set t < 500 Myr with the Galactic NSM rate ~10-4 yr-1. Moreover, our results are consistent with observed metallicity distribution and mass-metallicity relation of dSphs. We then find that the effects of gas mixing processes including metals in the star-forming region of a typical scale of giant molecular clouds ~ 10 - 100 pc play the significant roles in reproducing the measured dispersion in [Eu/Fe] vs. [Fe/H] of the metal-poor stars in dSphs. We also find that the star formation rate of ~ 10-3 M?yr-1 in early epoch (< 1 Gyr) of galactic halo evolution is necessary for this results. This study strongly supports that NSM is a major site of r-process.

  18. DOLFIN: Automated finite element computing

    E-print Network

    Logg, Anders; Wells, G N

    2009-02-25

    variational problem on V = H1(?) reads: Find u ? V : a (v, u) = L (v) ?v ? V, (2) where a(v, u) = ? ? ?v · ?u + vudx, (3) L(v) = ? ? vf dx. (4) To assemble and solve a linear system AU = b for the degrees of freedom U ? RN of a finite element approximation uh... are supported: (1) H1 conforming finite elements: (a) CGr, arbitrary degree continuous Lagrange elements. (2) H(div) conforming finite elements: (a) RTr, arbitrary degree Raviart–Thomas elements [Raviart and Thomas 1977]; (b) BDMr, arbitrary degree Brezzi...

  19. Dilute group III-V nitride intermediate band solar cells with contact blocking layers

    DOEpatents

    Walukiewicz, Wladyslaw; Yu, Kin Man

    2015-02-24

    An intermediate band solar cell (IBSC) is provided including a p-n junction based on dilute III-V nitride materials and a pair of contact blocking layers positioned on opposite surfaces of the p-n junction for electrically isolating the intermediate band of the p-n junction by blocking the charge transport in the intermediate band without affecting the electron and hole collection efficiency of the p-n junction, thereby increasing open circuit voltage (V.sub.OC) of the IBSC and increasing the photocurrent by utilizing the intermediate band to absorb photons with energy below the band gap of the absorber layers of the IBSC. Hence, the overall power conversion efficiency of a IBSC will be much higher than an conventional single junction solar cell. The p-n junction absorber layers of the IBSC may further have compositionally graded nitrogen concentrations to provide an electric field for more efficient charge collection.

  20. Dilute Group III-V nitride intermediate band solar cells with contact blocking layers

    DOEpatents

    Walukiewicz, Wladyslaw (Kensington, CA); Yu, Kin Man (Lafayette, CA)

    2012-07-31

    An intermediate band solar cell (IBSC) is provided including a p-n junction based on dilute III-V nitride materials and a pair of contact blocking layers positioned on opposite surfaces of the p-n junction for electrically isolating the intermediate band of the p-n junction by blocking the charge transport in the intermediate band without affecting the electron and hole collection efficiency of the p-n junction, thereby increasing open circuit voltage (V.sub.OC) of the IBSC and increasing the photocurrent by utilizing the intermediate band to absorb photons with energy below the band gap of the absorber layers of the IBSC. Hence, the overall power conversion efficiency of a IBSC will be much higher than an conventional single junction solar cell. The p-n junction absorber layers of the IBSC may further have compositionally graded nitrogen concentrations to provide an electric field for more efficient charge collection.

  1. Stopping power for low-velocity heavy ions: (0--1. 0)-MeV/nucleon Mg ions in 17 ( Z =22--79) elemental solids

    SciTech Connect

    Arstila, K.; Keinonen, J.; Tikkanen, P. )

    1990-04-01

    The stopping power for {sup 24,26}Mg ions in 17 ({ital Z}=22--79) elemental solids has been studied in the energy region 0--1.0 MeV/nucleon by application of the Doppler-shift attenuation method. At velocities 2{ital v}{sub 0}{lt}{ital v}{lt}5{ital v}{sub 0} ({ital v}{sub 0} the Bohr velocity), the scaling factors 1.10 (Ti), 0.90 (V), 0.93 (Fe), 0.97 (Co), 0.99 (Ni), 1.03 (Cu), 1.05 (Ge), 1.05 (Nb), 1.15 (Mo), 1.05 (Pd), 1.08 (Ag), 1.09 (Hf), 1.07 (Ta), 1.05 (W), 1.05 (Re), 1.05 (Pt), and 0.96 (Au) to the commonly used empirical electronic stopping power by Ziegler, Biersack, and Littmark were determined to an accuracy of {plus minus}5%. At velocities {ital v}{lt}2{ital v}{sub 0}, much higher electronic stopping power and different velocity dependence than predicted by the empirical model were obtained. The electronic stopping power was determined to an accuracy of {plus minus}5%. The reduction of the nuclear stopping power due to the polycrystalline structure of the slowing-down materials was taken into account in the deduction of the electronic stopping power.

  2. Stopping power for low-velocity heavy ions: (0-1.0)-MeV/nucleon Mg ions in 17 (Z=22-79) elemental solids

    NASA Astrophysics Data System (ADS)

    Arstila, K.; Keinonen, J.; Tikkanen, P.

    1990-04-01

    The stopping power for 24,26Mg ions in 17 (Z=22-79) elemental solids has been studied in the energy region 0-1.0 MeV/nucleon by application of the Doppler-shift attenuation method. At velocities 2v0<v<5v0 (v0 the Bohr velocity), the scaling factors 1.10 (Ti), 0.90 (V), 0.93 (Fe), 0.97 (Co), 0.99 (Ni), 1.03 (Cu), 1.05 (Ge), 1.05 (Nb), 1.15 (Mo), 1.05 (Pd), 1.08 (Ag), 1.09 (Hf), 1.07 (Ta), 1.05 (W), 1.05 (Re), 1.05 (Pt), and 0.96 (Au) to the commonly used empirical electronic stopping power by Ziegler, Biersack, and Littmark were determined to an accuracy of +/-5%. At velocities v<2v0, much higher electronic stopping power and different velocity dependence than predicted by the empirical model were obtained. The electronic stopping power was determined to an accuracy of +/-5%. The reduction of the nuclear stopping power due to the polycrystalline structure of the slowing-down materials was taken into account in the deduction of the electronic stopping power.

  3. A double stellar generation in the Globular Cluster NGC6656 (M 22). Two stellar groups with different iron and s-process element abundance

    E-print Network

    Marino, A F; Piotto, G; Villanova, S; Bedin, L R; Bellini, A; Renzini, A

    2009-01-01

    AIMS. In this paper we present the chemical abundance analysis from high resolution UVES spectra of seventeen bright giant stars of the Globular Cluster M~22. RESULTS. We obtained an average iron abundance of [Fe/H]=-1.76\\pm0.02 (internal errors only) and an \\alpha enhancement of 0.36\\pm0.04 (internal errors only). Na and O, and Al and O follow the well known anti-correlation found in many other GCs. We identified two groups of stars with significantly different abundances of the s-process elements Y, Zr and Ba. The relative numbers of the two group members are very similar to the ratio of the stars in the two SGBs of M22 recently found by Piotto (2009). Y and Ba abundances do not correlate with Na, O and Al. The s-element rich stars are also richer in iron and have higher Ca abundances. The results from high resolution spectra have been further confirmed by lower resolution GIRAFFE spectra of fourteen additional M22 stars. GIRAFFE spectra show also that the Eu -- a pure r-process element -- abundance is not ...

  4. Elemental segregation and subsequent precipitation during solidification of continuous cast Nb–V–Ti high-strength low-alloy steels

    SciTech Connect

    Zheng, Shuguo; Davis, Claire; Strangwood, Martin

    2014-09-15

    In this study, elemental segregation during solidification and subsequent precipitation behaviour in a continuous cast Nb–V–Ti high-strength low-alloy steel was investigated by optical microscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy and thermodynamic modelling. It is known that for steels with low carbon contents the pearlite that forms on slow cooling does so where the interdendritic liquid was present prior to final solidification. The alloying elements of Nb, Ti, Mn and V segregate into the interdendritic liquid during solidification, while Al preferentially segregates into the solidifying solid phase. The composition analysis on the slab samples verified the predicted element segregation behaviour, with a smaller difference in the concentrations of Mn and V in the pearlite and dendritic ferrite regions being observed compared to the Nb levels. Small (30–100 nm) spherical or irregular shaped Nb-rich precipitates (Nb(C, N) and (Nb, V)(C, N)) were mainly found in the pearlite regions, while angular Al-rich (60–300 nm) precipitates were found in the dendritic ferrite regions, in the form of AlN and complex AlN–V(C, N) precipitates. Small isolated ferrite regions surrounded by pearlite were observed in the microstructure and has two origins: one type is dendritic ferrite that appears as an isolated island due to a sectioning effect when observing the two-dimensional microstructure; the other is a ferrite idiomorph that forms in the interdendritic region due to the low carbon content of the steel. Accordingly, in these isolated ferrite islands two different precipitation behaviours are found; predominantly Al-rich particles in the dendritic regions or predominantly Nb-rich precipitates in the interdendritic ferrite idiomorphs. No Al-rich precipitates were observed in the interdendritic regions (pearlite or isolated ferrite idiomorphs) despite the Thermo-Calc predictions indicating a higher volume fraction of AlN in these regions compared to the dendritic regions. This is believed to be due to back diffusion of nitrogen after solidification reducing the available nitrogen, which reacts with the high Nb levels present. - Highlights: • Nb-rich precipitates (Nb(C, N) and (Nb, V)(C, N)) were mainly found in pearlite. • Angular Al-rich precipitates (AlN and AlN–V(C, N)) were found in dendritic ferrite. • Precipitation behaviour in isolated ferrite islands within pearlite was revealed. • Segregation of substitutional elements during solidification is retained. • Back diffusion of interstitial elements (C, N) occurred.

  5. Conservation of an Actinomyces viscosus T14V type 1 fimbrial subunit homolog among divergent groups of Actinomyces spp.

    PubMed Central

    Yeung, M K

    1992-01-01

    The type 1 fimbrial subunit gene of the human Actinomyces viscosus T14V was used as a DNA probe in Southern analyses to detect related DNA sequences in 16 of 30 strains of Actinomyces spp. under conditions of high stringency. The organisms with homology to the DNA probe included two human and six nonhuman A. viscosus, three human and three nonhuman A. naeslundii, and two A. bovis isolates. Homologous DNA sequences were not detected in strains of A. odontolyticus and A. israelii examined in this study. Northern (RNA) blot analysis revealed expression of a transcript from each of the A. viscosus and A. naeslundii strains and from one A. bovis strain that was comparable in size to that detected from A. viscosus T14V. Cell surface fimbriae were observed on a majority of the strains that expressed the transcript. Various degrees of cross-immunoreactivities between these strains and antibodies specific for type 1 fimbriae of A. viscosus T14V were also observed by colony immunoassay. Thus, the data clearly demonstrate the existence in, and expression by, divergent Actinomyces groups of genomic sequences that are closely related to the type 1 fimbriae of A. viscosus T14V. Images PMID:1347285

  6. “Structural Transformations in Ceramics: Perovskite-like Oxides and Group III, IV, and V Nitrides”

    SciTech Connect

    James P. Lewis , Dorian M. Hatch , and Harold T. Stokes

    2006-12-31

    1 Overview of Results and their Significance Ceramic perovskite-like oxides with the general formula (A. A0. ...)(B. B0. ...)O3and titanium-based oxides are of great technological interest because of their large piezoelectric and dielectric response characteristics.[1] In doped and nanoengineered forms, titantium dioxide finds increasing application as an organic and hydrolytic photocatalyst. The binary main-group-metal nitride compounds have undergone recent advancements of in-situ heating technology in diamond anvil cells leading to a burst of experimental and theoretical interest. In our DOE proposal, we discussed our unique theoretical approach which applies ab initio electronic calculations in conjunction with systematic group-theoretical analysis of lattice distortions to study two representative phase transitions in ceramic materials: (1) displacive phase transitions in primarily titanium-based perovskite-like oxide ceramics, and (2) reconstructive phase transitions in main-group nitride ceramics. A sub area which we have explored in depth is doped titanium dioxide electrical/optical properties.

  7. Main group tellurium heterocycles anchored by a P(2)(V)N(2) scaffold and their sulfur/selenium analogues.

    PubMed

    Nordheider, Andreas; Hüll, Katharina; Prentis, Joanna K D; Athukorala Arachchige, Kasun S; Slawin, Alexandra M Z; Woollins, J Derek; Chivers, Tristram

    2015-03-16

    A comprehensive investigation of reactions of alkali-metal derivatives of the ditelluro dianion [TePV(NtBu)(?-NtBu)]22– (L2–, E = Te) with p-block element halides produced a series of novel heterocycles incorporating P2VN2 rings, tellurium, and group 13–16 elements. The dianion engages in Te,Te?-chelation to the metal center in Ph2Ge and R2Sn (R = tBu, nBu, Ph) derivatives; similar behavior was noted for group 14 derivatives of L2– (E = S, Se). In the case of group 13 trihalides MCl3 (M = Ga, In), neutral spirocyclic complexes (L)M[NtBu(Te)PV(?-NtBu)2PIIIN(H)tBu)] (M = Ga, In) comprised of a Te,Te?-chelated ligand L2– and a N,Te-bonded ligand resulting from loss of Te and monoprotonation were obtained. In reactions with RPCl2 (R = tBu, Ad, iPr2N) a significant difference was observed between Se- and S-containing systems. In the former case, Se,Se?-chelated derivatives were formed in high yields, whereas the N,S-chelated isomers predominated for sulfur. All complexes were characterized by multinuclear (1H, 31P, 77Se, 119Sn, and 125Te) NMR spectroscopy; this technique was especially useful in the analysis of the mixture of (L)(Se) and (L)(SeSe) obtained from the reaction of Se2Cl2 with L2– (E = Te). Single-crystal X-ray structures were obtained for the spirocyclic In complex (9), (L)GePh2 (E = Te, 10), (L)SntBu2 (E = Te, 12a); E = Se, 12aSe, E = S, 12aS) and (L)(?-SeSe) (E = Te, 16). PMID:25719213

  8. Vibration of piezoelectric elements surrounded by fluid media Hemant Kamath, Morten Willatzen *, Roderick V.N. Melnik

    E-print Network

    Melnik, Roderick

    testing, ultrasonic flow-metering and ocean engineering. Such elements come in different forms and shapes most frequently used elements in many areas, including ultrason- ics applications [2,18,12,6,13]. While where the structure is in contact with another acoustically active media, e.g., a fluid and/or gas

  9. K shell and L subshell photoeffect cross-sections of some elements in the atomic range 50?Z?65 at 59.5 keV.

    PubMed

    Aylikci, V

    2015-01-01

    In this study, K and L shell photoeffect cross-sections were measured for the elements in the range of 50?Z?65 at 59. 5 keV. These photoeffect cross-sections were measured by using the experimental ?K?, production cross-section values measured in this paper and two different K shell fluorescence yield values in the literature. The results were compared with the calculated theoretical values. The values were plotted versus atomic number. PMID:25993814

  10. A measurement of the top quark mass in 1.96 TeV proton-antiproton collisions using a novel matrix element method

    SciTech Connect

    Freeman, John C.; /LBL, Berkeley

    2007-12-01

    A measurement of the top quark mass in t{bar t} {yields} l + jets candidate events, obtained from p{bar p} collisions at {radical}s = 1.96 TeV at the Fermilab Tevatron using the CDF II detector, is presented. The measurement approach is that of a matrix element method. For each candidate event, a two dimensional likelihood is calculated in the top pole mass and a constant scale factor, 'JES', where JES multiplies the input particle jet momenta and is designed to account for the systematic uncertainty of the jet momentum reconstruction. As with all matrix elements techniques, the method involves an integration using the Standard Model matrix element for tt production and decay. however, the technique presented is unique in that the matrix element is modified to compensate for kinematic assumptions which are made to reduce computation time. Background events are dealt with through use of an event observable which distinguishes signal from background, as well as through a cut on the value of an event's maximum likelihood. Results are based on a 955 pb{sup -1} data sample, using events with a high-p{sub T} lepton and exactly four high-energy jets, at least one of which is tagged as coming from a b quark; 149 events pass all the selection requirements. They find M{sub meas} = 169.8 {+-} 2.3(stat.) {+-} 1.4(syst.) GeV/c{sup 2}.

  11. A Measurement of the Top Quark Mass in 1.96 TeV Proton-Antiproton Collisions Using a Novel Matrix Element Method

    SciTech Connect

    CDF Collaboration; Freeman, John; Freeman, John

    2007-09-30

    A measurement of the top quark mass in t{bar t} {yields} l + jets candidate events, obtained from p{bar p} collisions at {radical}s = 1.96 TeV at the Fermilab Tevatron using the CDF II detector, is presented. The measurement approach is that of a matrix element method. For each candidate event, a two dimensional likelihood is calculated in the top pole mass and a constant scale factor, 'JES', where JES multiplies the input particle jet momenta and is designed to account for the systematic uncertainty of the jet momentum reconstruction. As with all matrix element techniques, the method involves an integration using the Standard Model matrix element for t{bar t} production and decay. However, the technique presented is unique in that the matrix element is modified to compensate for kinematic assumptions which are made to reduce computation time. Background events are dealt with through use of an event observable which distinguishes signal from background, as well as through a cut on the value of an event's maximum likelihood. Results are based on a 955 pb{sup -1} data sample, using events with a high-p{sub T} lepton and exactly four high-energy jets, at least one of which is tagged as coming from a b quark; 149 events pass all the selection requirements. They find M{sub meas} = 169.8 {+-} 2.3(stat.) {+-} 1.4(syst.) GeV/c{sup 2}.

  12. Characterization of Group V Dubnium Homologs on DGA Extraction Chromatography Resin from Nitric and Hydrofluoric Acid Matrices

    SciTech Connect

    Despotopulos, J D; Sudowe, R

    2012-02-21

    Studies of the chemical properties of superheavy elements (SHE) pose interesting challenges due to their short half-lives and low production rates. Chemical systems must have extremely fast kinetics, fast enough kinetics to be able to examine the chemical properties of interest before the SHE decays to another nuclide. To achieve chemistry on such time scales, the chemical system must also be easily automated. Most importantly however, a chemical system must be developed which provides suitable separation and kinetics before an on-line study of a SHE can be performed. Relativistic effects make studying the chemical properties of SHEs interesting due to the impact these effects could have on the SHEs chemical properties. Relativistic effects arise when the velocity of the s orbital electrons approach the speed of light. As this velocity increases, the Bohr radius of the inner electron orbitals decreases and there is an increase in the particles mass. This contraction results in a destabilization of the energy of the outer d and f electron orbitals (5f and 6d in the case of SHE), which can cause these to expand due to their increased shielding from the nuclear charge. Another relativistic effect is the spin-orbit splitting for p, d, and f orbitals into j = 1 {+-} 1/2 states. This can lead most interestingly to a possible increased stability of element 114, which due to large spin-orbit splitting of the 7p orbital and the relativistically stabilized 7p{sub 1/2} and 7s orbital gives rise to a closed shell ground state of 7s{sup 2}7p{sub 1/2}{sup 2}. The homologs of element 105, dubnium (Db), Ta and Nb and the pseudo-homolog Pa, are well known to hydrolyze and form both neutral and non-neutral monoatomic and polyatomic species that may cause issues with extraction from a given chemical system. Early ion-exchange and solvent-extraction studies show mixed results for the behavior of Db. Some studies show Db behaving most similar to Ta, while others show it behaving somewhere between Nb and Pa. Much more recent studies have examined the properties of Db from HNO{sub 3}/HF matrices, and suggest Db forms complexes similar to those of Pa. Very little experimental work into the behavior of element 114 has been performed. Thermochromatography experiments of three atoms of element 114 indicate that the element 114 is at least as volatile as Hg, At, and element 112. Lead was shown to deposit on gold at temperatures about 1000 C higher than the atoms of element 114. Results indicate a substantially increased stability of element 114. No liquid phase studies of element 114 or its homologs (Pb, Sn, Ge) or pseudo-homologs (Hg, Cd) have been performed. Theoretical predictions indicate that element 114 is should have a much more stable +2 oxidation state and neutral state than Pb, which would result in element 114 being less reactive and less metallic than Pb. The relativistic effects on the 7p{sub 1/2} electrons are predicted to cause a diagonal relationship to be introduced into the periodic table. Therefore, 114{sup 2+} is expected to behave as if it were somewhere between Hg{sup 2+}, Cd{sup 2+}, and Pb{sup 2+}. In this work two commercially available extraction chromatography resins are evaluated, one for the separation of Db homologs and pseudo?homologs from each other as well as from potential interfering elements such as Group IV Rf homologs and actinides, and the other for separation of element 114 homologs. One resin, Eichrom's DGA resin, contains a N,N,N',N'-tetra-n-octyldiglycolamide extractant, which separates analytes based on both size and charge characteristics of the solvated metal species, coated on an inert support. The DGA resin was examined for Db chemical systems, and shows a high degree of selectivity for tri-, tetra-, and hexavalent metal ions in multiple acid matrices with fast kinetics. The other resin, Eichrom's Pb resin, contains a di-t-butylcyclohexano 18-crown-6 extractant with isodecanol solvent, which separates analytes based on steric interactions between the cavity of the crown ether and electrostatic interac

  13. Porous Silica Sol-Gel Glasses Containing Reactive V2O5 Groups

    NASA Technical Reports Server (NTRS)

    Stiegman, Albert E.

    1995-01-01

    Porous silica sol-gel glasses into which reactive vanadium oxide functional groups incorporated exhibit number of unique characteristics. Because they bind molecules of some species both reversibly and selectively, useful as chemical sensors or indicators or as scrubbers to remove toxic or hazardous contaminants. Materials also oxidize methane gas photochemically: suggests they're useful as catalysts for conversion of methane to alcohol and for oxidation of hydrocarbons in general. By incorporating various amounts of other metals into silica sol-gel glasses, possible to synthesize new materials with broad range of new characteristics.

  14. Fossil group origins V. The dependence of the luminosity function on the magnitude gap

    E-print Network

    Zarattini, S; Sanchez-Janssen, R; Barrena, R; Boschin, W; del Burgo, C; Castro-Rodriguez, N; Corsini, E M; D'Onghia, E; Girardi, M; Iglesias-Paramo, J; Kundert, A; Mendez-Abreu, J; Vilchez, J M

    2015-01-01

    In nature we observe galaxy aggregations that span a wide range of magnitude gaps between the two first-ranked galaxies of a system ($\\Delta m_{12}$). There are systems with gaps close to zero (e.g., the Coma cluster), and at the other extreme of the distribution, the largest gaps are found among the so-called fossil systems. Fossil and non-fossil systems could have different galaxy populations that should be reflected in their luminosity functions. In this work we study, for the first time, the dependence of the luminosity function parameters on $\\Delta m_{12}$ using data obtained by the fossil group origins (FOGO) project. We constructed a hybrid luminosity function for 102 groups and clusters at $z \\le 0.25$. We stacked all the individual luminosity functions, dividing them into bins of $\\Delta m_{12}$, and studied their best-fit Schechter parameters. We additionally computed a relative luminosity function, expressed as a function of the central galaxy luminosity, which boosts our capacity to detect differ...

  15. Fossil group origins. V. The dependence of the luminosity function on the magnitude gap

    NASA Astrophysics Data System (ADS)

    Zarattini, S.; Aguerri, J. A. L.; Sánchez-Janssen, R.; Barrena, R.; Boschin, W.; del Burgo, C.; Castro-Rodriguez, N.; Corsini, E. M.; D'Onghia, E.; Girardi, M.; Iglesias-Páramo, J.; Kundert, A.; Méndez-Abreu, J.; Vilchez, J. M.

    2015-09-01

    Context. In nature we observe galaxy aggregations that span a wide range of magnitude gaps between the two first-ranked galaxies of a system (?m12). Thus, there are systems with gaps close to zero (e.g., the Coma cluster), and at the other extreme of the distribution, the largest gaps are found among the so-called fossil systems. The observed distribution of magnitude gaps is thought to be a consequence of the orbital decay of M? galaxies in massive halos and the associated growth of the central object. As a result, to first order the amplitude of this gap is a good statistical proxy for the dynamical age of a system of galaxies. Fossil and non-fossil systems could therefore have different galaxy populations that should be reflected in their luminosity functions. Aims: In this work we study, for the first time, the dependence of the luminosity function parameters on ?m12 using data obtained by the fossil group origins (FOGO) project. Methods: We constructed a hybrid luminosity function for 102 groups and clusters at z ? 0.25 using both photometric data from the SDSS-DR7 and redshifts from the DR7 and the FOGO surveys. The latter consists of ~1200 new redshifts in 34 fossil system candidates. We stacked all the individual luminosity functions, dividing them into bins of ?m12, and studied their best-fit Schechter parameters. We additionally computed a "relative" luminosity function, expressed as a function of the central galaxy luminosity, which boosts our capacity to detect differences - especially at the bright end. Results: We find trends as a function of ?m12 at both the bright and faint ends of the luminosity function. In particular, at the bright end, the larger the magnitude gap, the fainter the characteristic magnitude M?. The characteristic luminosity in systems with negligible gaps is more than a factor three brighter than in fossil-like ones. Remarkably, we also find differences at the faint end. In this region, the larger the gap, the flatter the faint-end slope ?. Conclusions: The differences found at the bright end support a dissipationless, dynamical friction-driven merging model for the growth of the central galaxy in group- and cluster-sized halos. The differences in the faint end cannot be explained by this mechanism. Other processes - such as enhanced tidal disruption due to early infall and/or prevalence of eccentric orbits - may play a role. However, a larger sample of systems with ?m12> 1.5 is needed to establish the differences at the faint end.

  16. 75 FR 45623 - Morris Energy Group, LLC v.PSEG Energy Resources & Trade LLC; PSEG Fossil LLC; and PSEG Power LLC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-03

    ...Energy Group, LLC v.PSEG Energy Resources & Trade LLC; PSEG Fossil LLC; and PSEG Power LLC; Notice of Complaint July 27, 2010...complaint against PSEG Energy Resources & Trade, LLC, PSEG Fossil LLC and PSEG Power LLC (PSEG Power Companies)...

  17. The origin and distribution of HAPs elements in relation to maceral composition of the A1 lignite bed (Paleocene, Calvert Bluff Formation, Wilcox Group), Calvert mine area, east-central Texas

    USGS Publications Warehouse

    Crowley, S.S.; Warwick, P.D.; Ruppert, L.F.; Pontolillo, J.

    1997-01-01

    The origin and distribution of twelve potentially Hazardous Air Pollutants (HAPs; As, Be, Cd, Cr, Co, Hg, Mn, Ni, Pb Sb, Se, and U) identified in the 1990 Clean Air Act Amendments were examined in relation to the maceral composition of the A1 bed (Paleocene, Calvert Bluff Formation, Wilcox Group) of the Calvert mine in east-central Texas. The 3.2 m-thick A1 bed was divided into nine incremental channel samples (7 lignite samples and 2 shaley coal samples) on the basis of megascopic characteristics. Results indicate that As, Cd, Cr, Ni, Pb, Sb, and U are strongly correlated with ash yield and are enriched in the shaley coal samples. We infer that these elements are associated with inorganic constituents in the coal bed and may be derived from a penecontemporaneous stream channel located several kilometers southeast of the mining block. Of the HAPs elements studied, Mn and Hg are the most poorly correlated to ash yield. We infer an organic association for Mn; Hg may be associated with pyrite. The rest of the trace elements (Be, Co, and Se) are weakly correlated with ash yield. Further analytical work is necessary to determine the mode of occurrence for these elements. Overall, concentrations of the HAPs elements are generally similar to or less than those reported in previous studies of lignites of the Wilcox Group, east-central region, Texas. Petrographic analysis indicates the following ranges in composition for the seven lignite samples: liptinites (5-8%), huminites (88-95%), and inertinites (trace amounts to 7%). Samples from the middle portion of the A1 bed contain abundant crypto-eugelinite compared to the rest of the samples; this relationship suggests that the degradation of plant material was an important process during the development of the peat mire. With the exception of Hg and Mn, relatively low levels of the HAPs elements studied are found in the samples containing abundant crypto-eugelinite. We infer that the peat-forming environment for this portion of the coal bed was very wet with minimal detrital input. Relatively high concentrations of crypto-humotelinite were found in samples from the top and base of the coal bed. The presence of abundant crypto-humotelinite in this part of the coal bed suggests the accumulation of wood-rich peat under conditions conducive to a high degree of tissue preservation in the peat mire. Although several of the trace elements (Be, Co, Ni, and Sb) exhibit enrichment in these samples, they are not necessarily chemically associated with humotelinite. We infer that these elements, with the exception of Be, are possibly associated with deposition of the roof and floor rock of the coal bed; however, further analytical work would be necessary to confirm this hypothesis. Beryllium may have an organic origin. ?? 1997 Elsevier Science B.V.

  18. Spin Density Matrix Elements in Exclusive rho^0 Electroproduction on 1H and 2H Targets at 27.5 GeV Beam Energy

    E-print Network

    HERMES Collaboration; A. Airapetian

    2009-06-13

    Spin Density Matrix Elements (SDMEs) describing the angular distribution of exclusive rho^0 electroproduction and decay are determined in the HERMES experiment with 27.6 GeV beam energy and unpolarized hydrogen and deuterium targets. Eight (fifteen) SDMEs that are related (unrelated) to the longitudinal polarization of the beam are extracted in the kinematic region 1 GeV^2 < Q^2 < 7 GeV^2, 3.0 GeV < W < 6.3 GeV, and -t < 0.4 GeV^2. Within the given experimental uncertainties, a hierarchy of relative sizes of helicity amplitudes is observed. Kinematic dependences of all SDMEs on Q^2 and t are presented, as well as the longitudinal-to-transverse rho^0 electroproduction cross section ratio as a function of Q^2. A small but statistically significant deviation from the hypothesis of s-channel helicity conservation is observed. An indication is seen of a contribution of unnatural-parity-exchange amplitudes; these amplitudes are naturally generated with a quark-exchange mechanism.

  19. Ages and sources of components of Zn-Pb, Cu, precious metal, and platinum group element deposits in the goodsprings district, clark county, Nevada

    USGS Publications Warehouse

    Vikre, P.; Browne, Q.J.; Fleck, R.; Hofstra, A.; Wooden, J.

    2011-01-01

    The Goodsprings district, Clark County, Nevada, includes zinc-dominant carbonate replacement deposits of probable late Paleozoic age, and lead-dominant carbonate replacement deposits, copper ?? precious metal-platinum group element (PGE) deposits, and gold ?? silver deposits that are spatially associated with Late Triassic porphyritic intrusions. The district encompasses ??500 km2 although the distribution of all deposits has been laterally condensed by late Mesozoic crustal contraction. Zinc, Pb, and Cu production from about 90 deposits was ??160,000 metric tons (t) (Zn > Pb >> Cu), 2.1 million ounces (Moz) Ag, 0.09 Moz Au, and small amounts of PGEs-Co, V, Hg, Sb, Ni, Mo, Mn, Ir, and U-were also recovered. Zinc-dominant carbonate replacement deposits (Zn > Pb; Ag ?? Cu) resemble Mississippi Valley Type (MVT) Zn-Pb deposits in that they occur in karst and fault breccias in Mississippian limestone where the southern margin of the regional late Paleozoic foreland basin adjoins Proterozoic crystalline rocks of the craton. They consist of calcite, dolomite, sphalerite, and galena with variably positive S isotope compositions (??34S values range from 2.5-13%), and highly radiogenic Pb isotope compositions (206Pb/204Pb >19), typical of MVT deposits above crystalline Precambrian basement. These deposits may have formed when southward flow of saline fluids, derived from basinal and older sedimentary rocks, encountered thinner strata and pinch-outs against the craton, forcing fluid mixing and mineral precipitation in karst and fault breccias. Lead-dominant carbonate replacement deposits (Pb > Zn, Ag ?? Cu ?? Au) occur among other deposit types, often near porphyritic intrusions. They generally contain higher concentrations of precious metals than zinc-dominant deposits and relatively abundant iron oxides after pyrite. They share characteristics with copper ?? precious metal- PGE and gold ?? silver deposits including fine-grained quartz replacement of carbonate minerals in ore breccias and relatively low S and Pb isotope values (??34S values vary from 0-??4%; 206Pb/204Pb <18.5). Copper ?? precious metal-PGE deposits (Cu, Co, Ag, Au, Pd, and Pt) consist of Cu carbonate minerals (after chalcocite and chalcopyrite) and fine-grained quartz that have replaced breccia clasts and margins of fissures in Paleozoic limestones and dolomites near porphyritic intrusions. Gold ?? silver deposits occur along contacts and within small-volume stocks and dikes of feldspar porphyry, one textural variety of porphyritic intrusions. Lead isotope compositions of copper ?? precious metal-PGE, gold ?? silver, and lead-dominant carbonate replacement deposits are similar to those of Mojave crust plutons, indicating derivation of Pb from 1.7 Ga crystalline basement or from Late Proterozoic siliciclastic sedimentary rocks derived from 1.7 Ga crystalline basement. Four texturally and modally distinctive porphyritic intrusions are exposed largely in the central part of the district: feldspar quartz porphyry, plagioclase quartz porphyry, feldspar biotite quartz porphyry, and feldspar porphyry. Intrusions consist of 64 to 70 percent SiO2 and variable K2O/Na2O (0.14-5.33) that reflect proportions of K-feldspar and albite phenocrysts and megacrysts as well as partial alteration to K-mica; quartz and biotite phenocrysts are present in several subtypes. Albite may have formed during emplacement of magma in brine-saturated basinal strata, whereas hydrothermal alteration of matrix, phenocrystic, and megacrystic feldspar and biotite to K-mica, pyrite, and other hydrothermal minerals occurred during and after intrusion emplacement. Small volumes of garnet-diopside-quartz and retrograde epidote-mica-amphibole skarn have replaced carbonate rocks adjacent to one intrusion subtype (feldspar-quartz porphyry), but alteration of carbonate rocks at intrusion contacts elsewhere is inconsp. Uranium-lead ages of igneous zircons vary inconsistently from ?? 180 to 230

  20. Two Similarity Reductions and New Solutions for the Generalized Variable-Coefficient KdV Equation by Using Symmetry Group Method

    E-print Network

    Rehab M. El-Shiekh

    2015-12-14

    In this paper, a generalized variable-coefficient KdV equation (vcKdV) arising in fluid mechanics, plasma physics and ocean dynamics is investigated by using symmetry group analysis. Two basic generators are determined, and for every generator in the optimal system the admissible forms of the coefficients and the corresponding reduced ordinary differential equation are obtained. The search for solutions to those reduced ordinary differential equations yields many new solutions for the generalized vcKdV equation.

  1. III-V arsenide-nitride semiconductor

    NASA Technical Reports Server (NTRS)

    Major, Jo S. (Inventor); Welch, David F. (Inventor); Scifres, Donald R. (Inventor)

    2000-01-01

    III-V arsenide-nitride semiconductor are disclosed. Group III elements are combined with group V elements, including at least nitrogen and arsenic, in concentrations chosen to lattice match commercially available crystalline substrates. Epitaxial growth of these III-V crystals results in direct bandgap materials, which can be used in applications such as light emitting diodes and lasers. Varying the concentrations of the elements in the III-V materials varies the bandgaps, such that materials emitting light spanning the visible spectra, as well as mid-IR and near-UV emitters, can be created. Conversely, such material can be used to create devices that acquire light and convert the light to electricity, for applications such as full color photodetectors and solar energy collectors. The growth of the III-V material can be accomplished by growing thin layers of elements or compounds in sequences that result in the overall lattice match and bandgap desired.

  2. Simultaneous removal of elemental mercury and NO from flue gas by V2O5-CeO2/TiO2 catalysts

    NASA Astrophysics Data System (ADS)

    Zhang, Xunan; Li, Caiting; Zhao, Lingkui; Zhang, Jie; Zeng, Guangming; Xie, Yin'e.; Yu, Ming'e.

    2015-08-01

    A series of Ce-doped V2O5/TiO2 catalysts synthesized by an ultrasound assisted impregnation method were employed to investigate simultaneous removal of elemental mercury (Hg0) and NO in lab-scale experiments. Scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), X-ray diffractogram (XRD), and X-ray photoelectron spectroscopy (XPS) analyses were used to characterize the samples. Compared to TiO2 support, the catalytic performance of CeO2 doped on both TiO2 and V2O5/TiO2 catalysts have been improved. Remarkably, 1%V2O5-10% CeO2/TiO2 (V1Ce10Ti) exhibited the highest Hg0 oxidation efficiency of 81.55% at 250 °C with a desired NO removal efficiency under the same condition. Both the NO conversion and Hg0 oxidation efficiency were enhanced in the presence of O2. The activity was inhibited by the injection of NH3 with the increase of NH3/NO. When in the presence of 400 ppm SO2, Hg0 oxidation was slightly affected. Furthermore, Hg0 removal behavior under both oxidation and selective catalytic reduction (SCR) condition over V1Ce10Ti were well investigated to further probe into the feasibility of one single unit for multi-pollutants control in industry application. The existence of the redox cycle of V4+ + Ce4+ ? V5+ + Ce3+ in V2O5-CeO2/TiO2 catalyst could not only greatly improve the NO conversion, but also promote the oxidation of Hg0.

  3. M-shell X-ray production cross-sections for elements with 67 {<=} Z {<=} 92 at incident photon energies E{sub M{sub 1}}V

    SciTech Connect

    Chauhan, Yogeshwar; Kumar, Anil; Puri, Sanjiv

    2009-07-15

    The X-ray production cross-sections for the Mk (k = {xi}, {delta}, {alpha}, {beta}, {zeta}, {gamma}, m{sub 1} and m{sub 2}) groups of X-rays have been evaluated for all the elements with 67 {<=} Z {<=} 92 at incident photon energies ranging E{sub M{sub 1}}V using currently available theoretical data sets of different physical parameters, namely, partial photoionization cross-sections, X-ray emission rates, fluorescence and Coster-Kronig yields, and the K-shell/L{sub j} (j = 1-3) subshell to the M{sub i} (i = 1-5) subshell vacancy transfer probabilities, based on the independent particle models.

  4. Group B streptococci escape host immunity by deletion of tandem repeat elements of the alpha C protein.

    PubMed Central

    Madoff, L C; Michel, J L; Gong, E W; Kling, D E; Kasper, D L

    1996-01-01

    Group B streptococci (GBS) are the most common cause of neonatal sepsis, pneumonia, and meningitis. The alpha C protein is a surface-associated antigen; the gene (bca) for this protein contains a series of tandem repeats (each encoding 82 aa) that are identical at the nucleotide level and express a protective epitope. We previously reported that GBS isolates from two of 14 human maternal and neonatal pairs differed in the number of repeats contained in their alpha C protein; in both pairs, the alpha C protein of the neonatal isolate was smaller in molecular size. We now demonstrate by PCR that the neonatal isolates contain fewer tandem repeats. Maternal isolates were susceptible to opsonophagocytic killing in the presence of alpha C protein-specific antiserum, whereas the discrepant neonatal isolates proliferated. An animal model was developed to further study this phenomenon. Adult mice passively immunized with antiserum to the alpha C protein were challenged with an alpha C protein-expressing strain of GBS. Splenic isolates of GBS from these mice showed a high frequency of mutation in bca--most commonly a decrease in repeat number. Isolates from non-immune mice were not altered. Spontaneous deletions in the repeat region were observed at a much lower frequency (6 x 10(-4)); thus, deletions in that region are selected for under specific antibody pressure and appear to lower the organism's susceptibility to killing by antibody specific to the alpha C protein. This mechanism of antigenic variation may provide a means whereby GBS evade host immunity. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:8633028

  5. Effect of replacing a hydroxyl group with a methyl group on arsenic (V) species adsorption on goethite (alpha-FeOOH).

    PubMed

    Zhang, J S; Stanforth, R S; Pehkonen, S O

    2007-02-01

    Arsenate and methylated arsenicals, such as dimethylarsinate (DMA) and monomethylarsonate (MMA), are being found with increasing frequency in natural water systems. The mobility and bioavailability of these arsenic species in the environment are strongly influenced by their interactions with mineral surface, especially iron and aluminum oxides. Goethite (alpha-FeOOH), one of the most abundant ferric (hydr)oxides in natural systems, has a high retention capacity for arsenic species. Unfortunately, the sorption mechanism for the species is not completely understood, which limits our ability to model their behavior in natural systems. The purpose of this study is to investigate the effect of replacing a hydroxyl group with a methyl group on the adsorption behaviors of arsenic (V) species using adsorption edges, the influence of the background electrolyte on arsenic adsorption, and their effect on the zeta potential of goethite. The affinity of the three species to the goethite surface decreases in the order of AsO4=MMA>DMA. The uptake of DMA and MMA is independent of the concentration of background electrolyte, indicating that both species form inner-sphere complexes on the goethite surface and the most charge of adsorbed DMA and MMA locates at the surface plane. Arsenate uptake increases with increasing concentrations of background electrolyte at pH above 4, possibly due to that the charge of adsorbed arsenate is distributed between the surface plane and another electrostatic plane. DMA and lower concentrations of MMA have small effect on the zeta potential, whereas the zeta potential of goethite decreases in the presence of arsenate. The small effect on zeta potential of DMA or MMA adsorption suggests that the sorption sites for the anions is not important in controlling the surface charge. This observation is inconsistent with most adsorption models that postulate a singly coordinated hydroxyls contributing to both the adsorption and the surface charge, but supports the thesis that the charge on the goethite surface comes primarily from protonation of the triply bound oxygen atoms on the surface. PMID:17056055

  6. Platinum-group element, Gold, Silver and Base Metal distribution in compositionally zoned sulfide droplets from the Medvezky Creek Mine, Noril'sk, Russia

    USGS Publications Warehouse

    Barnes, S.-J.; Cox, R.A.; Zientek, M.L.

    2006-01-01

    Concentrations of Ag, Au, Cd, Co, Re, Zn and Platinum-group elements (PGE) have been determined in sulfide minerals from zoned sulfide droplets of the Noril'sk 1 Medvezky Creek Mine. The aims of the study were; to establish whether these elements are located in the major sulfide minerals (pentlandite, pyrrhotite, chalcopyrite and cubanite), to establish whether the elements show a preference for a particular sulfide mineral and to investigate the model, which suggests that the zonation in the droplets is caused by the crystal fractionation of monosulfide solid solution (mss). Nickel, Cu, Ag, Re, Os, Ir, Ru, Rh and Pd, were found to be largely located in the major sulfide minerals. In contrast, less than 25% of the Au, Cd, Pt and Zn in the rock was found to be present in these sulfides. Osmium, Ir, Ru, Rh and Re were found to be concentrated in pyrrhotite and pentlandite. Palladium and Co was found to be concentrated in pentlandite. Silver, Cd and Zn concentrations are highest in chalcopyrite and cubanite. Gold and platinum showed no preference for any of the major sulfide minerals. The enrichment of Os, Ir, Ru, Rh and Re in pyrrhotite and pentlandite (exsolution products of mss) and the low levels of these elements in the cubanite and chalcopyrite (exsolution products of intermediate solid solution, iss) support the mss crystal fractionation model, because Os, Ir, Ru, Rh and Re are compatible with mss. The enrichment of Ag, Cd and Zn in chalcopyrite and cubanite also supports the mss fractionation model these minerals are derived from the fractionated liquid and these elements are incompatible with mss and thus should be enriched in the fractionated liquid. Gold and Pt do not partition into either iss or mss and become sufficiently enriched in the final fractionated liquid to crystallize among the iss and mss grains as tellurides, bismithides and alloys. During pentlandite exsolution Pd appears to have diffused from the Cu-rich portion of the droplet into pentlandite. ?? Springer-Verlag 2006.

  7. The origin and evolution of the odd-Z iron-peak elements Sc, V, Mn, and Co in the Milky Way stellar disk

    NASA Astrophysics Data System (ADS)

    Battistini, Chiara; Bensby, Thomas

    2015-05-01

    Context. Elements heavier than Li are produced in the interiors of stars. However, for many elements the exact production sites and the timescales on which they are dispersed into the interstellar medium are unknown. Having a clear picture on the origins of the elements is important for our ability to trace and understand the formation and chemical evolution of the Milky Way and its stellar populations. Aims: The aim of this study is to investigate the origin and evolution of Sc, V, Mn, and Co for a homogeneous and statistically significant sample of stars probing the different populations of the Milky Way, in particular the thin and thick disks. Methods: Using high-resolution spectra obtained with the MIKE, FEROS, SOFIN, FIES, UVES, and HARPS spectrographs, we determine Sc, V, Mn, and Co abundances for a large sample of F and G dwarfs in the solar neighborhood. The method is based on spectral synthesis and using one-dimensional, plane-parallel, local thermodynamic equilibrium (LTE) model stellar atmospheres calculated with the MARCS 2012 code. The non-LTE (NLTE) corrections from the literature were applied to Mn and Co. Results: We find that the abundance trends derived for Sc (594 stars), V (466 stars), and Co (567 stars) are very similar to what has been observed for the ?-elements in the thin and thick disks. On the contrary, Mn (569 stars) is generally underabundant relative to the Sun (i.e., [ Mn/Fe ] < 0) for [ Fe/H ] < 0. In addition, for Mn, when NLTE corrections are applied, the trend changes and is almost flat over the entire metallicity range of the stars in our sample (-2 ? [ Fe/H ] ? + 0.4). The [Sc/Fe]-[Fe/H] abundance trends show a small separation between the thin and thick disks, while for V and Co they completely overlap. For Mn there is a small difference in [Mn/Fe], but only when NLTE corrections are used. Comparisons with Ti as a reference element show flat trends for all the elements except for Mn that show well separated [Mn/Ti]-[Ti/H] trends for the thin and thick disks. Conclusions: The elements Sc and V present trends compatible with production from type II supernovae (SNII) events. In addition, Sc clearly shows a metallicity dependence for [ Fe/H ] < -1. Instead, Mn is produced in SNII events for [ Fe/H ] ? -0.4 and then type Ia supernovae start to produce Mn. Finally, Co appears to be produced mainly in SNII with suggestion of enrichment from hypernovae at low metallicities. This paper includes data gathered with the 6.5 m Magellan Telescopes located at the Las Campanas Observatory, Chile; the Nordic Optical Telescope (NOT) on La Palma, Spain; the Very Large Telescope (VLT) at the European Southern Observatory (ESO) on Paranal, Chile (ESO Proposal ID 69.B-0277 and 72.B-0179); the ESO 1.5-m, 2.2-m. and 3.6-m telescopes on La Silla, Chile (ESO Proposal ID 65.L-0019, 67.B-0108, 76.B-0416, 82.B-0610); and data from UVES Paranal Observatory Project (ESO DDT Program ID 266.D-5655).Full versions of Tables 2 and 5 are only 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/577/A9Appendices are available in electronic form at http://www.aanda.org

  8. 20 CFR 655.1115 - Element V-What does “no strike/lockout or layoff” mean?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...attestation element, the facility must notify ETA if a strike or lockout of nurses...described in this section from a facility, ETA will examine the documentation, and may...facility or other appropriate entities. If ETA determines that the strike or lockout...

  9. New elastic electron scattering factors for the elements for incident energies of 10, 40, 60, and 90 keV

    SciTech Connect

    Ross, A.W.; Fink, M.

    1986-12-01

    An improved set of scattering factors for all neutral elements has bee completed for inclusion in the new edition of the International Tables of X-ray Crystallography . These calculations are compared with the former electron scattering factors and the deviations between the two are discussed.(AIP)

  10. Determination of K?,? excitation factors in thin target for selected elements from Y to Te at 59.54keV excitation energy.

    PubMed

    Akman, F; Akdemir, F; Durak, R; Kaçal, M R; Aksakal, O; Araz, A

    2016-01-01

    The paper presents the first measurements of the K? and K? excitation factors for some selected elements from Y to Te. To determine the K? and K? excitation factors, the experimental values of K shell X-ray production cross sections and total absorption photoelectric cross sections were used. The measurements were performed using a Si(Li) detector coupled with 2048 multichannel analyzer and an Am-241 annular radioisotope source which is emitted 59.54keV ?-photons. It is observed that the K? excitation factors are 5-6 times larger than the K? excitation factors. The measured excitation factors were compared only with theoretical calculated ones since there are no other experimental reports for the present elements in the literature. The present experimental values of K? and K? excitation factors are in satisfactory agreement with the theoretical results. PMID:26623929

  11. Comparative mitochondrial genomics in zygomycetes: bacteria-like RNase P RNAs, mobile elements and a close source of the group I intron invasion in angiosperms

    PubMed Central

    Seif, Elias; Leigh, Jessica; Liu, Yu; Roewer, Ingeborg; Forget, Lise; Lang, B. Franz

    2005-01-01

    To generate data for comparative analyses of zygomycete mitochondrial gene expression, we sequenced mtDNAs of three distantly related zygomycetes, Rhizopus oryzae, Mortierella verticillata and Smittium culisetae. They all contain the standard fungal mitochondrial gene set, plus rnpB, the gene encoding the RNA subunit of the mitochondrial RNase P (mtP-RNA) and rps3, encoding ribosomal protein S3 (the latter lacking in R.oryzae). The mtP-RNAs of R.oryzae and of additional zygomycete relatives have the most eubacteria-like RNA structures among fungi. Precise mapping of the 5? and 3? termini of the R.oryzae and M.verticillata mtP-RNAs confirms their expression and processing at the exact sites predicted by secondary structure modeling. The 3? RNA processing of zygomycete mitochondrial mRNAs, SSU-rRNA and mtP-RNA occurs at the C-rich sequence motifs similar to those identified in fission yeast and basidiomycete mtDNAs. The C-rich motifs are included in the mature transcripts, and are likely generated by exonucleolytic trimming of RNA 3? termini. Zygomycete mtDNAs feature a variety of insertion elements: (i) mtDNAs of R.oryzae and M.verticillata were subject to invasions by double hairpin elements; (ii) genes of all three species contain numerous mobile group I introns, including one that is closest to an intron that invaded angiosperm mtDNAs; and (iii) at least one additional case of a mobile element, characterized by a homing endonuclease insertion between partially duplicated genes [Paquin,B., Laforest,M.J., Forget,L., Roewer,I., Wang,Z., Longcore,J. and Lang,B.F. (1997) Curr. Genet., 31, 380–395]. The combined mtDNA-encoded proteins contain insufficient phylogenetic signal to demonstrate monophyly of zygomycetes. PMID:15689432

  12. Vaporization and atomization of the platinum group elements in the graphite furnace investigated by electrothermal vaporization-inductively coupled plasma-mass spectrometry

    NASA Astrophysics Data System (ADS)

    Byrne, J. P.; Grégoire, D. C.; Benyounes, M. E.; Chakrabarti, C. L.

    1997-09-01

    The mechanisms by which the platinum group elements (PGEs) are vaporized in the graphite furnace have been investigated using electrothermal vaporization-inductively coupled plasma-mass spectrometry (ETV-ICP-MS). The results suggest that live of these elements (Ru, Rh, Pd, Ir and Pt) are reduced to their metallic state in the graphite furnace and then vaporized by direct sublimation of the metal. For Os, the vaporization mechanism is different. In the presence of HNO 3, two distinct vaporization processes are observed. Volatile oxides of Os are released at low temperatures, but some of this oxide is reduced to relatively involatile Os metal which is then vaporized when the temperature is increased above 2000°C. The addition of TeCl 2 chemical modifier was found to have minimal effect on the vaporization mechanism and sensitivity for determination for five of the PGEs. For Os, however, the analytical sensitivity and limit of detection was improved when Te modifier was used in conjunction with a lower vaporization temperature of 1400°C. Optimum conditions for the determination of the PGEs by ETV-ICP-MS are reported, along with their absolute limits of detection; these range from 0.015 pg for Ir to 0.25 pg for Os.

  13. HRTEM-AEM-HAADF-STEM study of platinum-group elements within a mantle-derived Cr spinel (Lherz; North-Eastern Pyrenees, France)

    NASA Astrophysics Data System (ADS)

    Ferraris, Cristiano; Lorand, Jean-Pierre

    2008-11-01

    As platinum group elements (PGE) like Ru, Os, Ir and Rh have appropriate charge and ionic radii to substitute the major cations in the spinel structure, Cr-spinel is one of the potential minerals that can fractionate such elements during the partial melting and fractional crystallization. However, whether PGE occur in solid solution or are physically collected as poly-metallic clusters of atoms on spinel grain boundaries is a central issue for PGE geochemistry. A PGE-bearing Cr-spinel separated from one harzburgite sample from Lherz has been analyzed by Transmission, Analytical and Scanning-Transmission Electron Microscopy (TEM-AEM-STEM). Our analyses did not reveal any exsolution/cluster feature at the nanometric scale, except for Ir, which is concentrated as Ir-bearing lamellar rutile, about 100 nm width. Rutile appears to have enhanced unmixing of Ir from the spinel structure. The DCr spinel/silicate melt partition coefficients estimated from the Lherz Cr-spinel (Ir = 32 ± 0.7; Os = 28 ± 6; Ru = 12.5 ± 2; Pt = 1.5 ± 0.2; Pd = 0.2 ± 0.05) may be appropriate for modelling the behavior of PGE in sulfur-undersaturated melting processes of the shallow upper mantle, while being lower than those derived from experiments and natural ultramafic melts.

  14. Correlation consistent basis sets for explicitly correlated wavefunctions: Pseudopotential-based basis sets for the post-d main group elements Ga-Rn

    NASA Astrophysics Data System (ADS)

    Hill, J. Grant; Peterson, Kirk A.

    2014-09-01

    New correlation consistent basis sets, cc-pVnZ-PP-F12 (n = D, T, Q), for all the post-d main group elements Ga-Rn have been optimized for use in explicitly correlated F12 calculations. The new sets, which include not only orbital basis sets but also the matching auxiliary sets required for density fitting both conventional and F12 integrals, are designed for correlation of valence sp, as well as the outer-core d electrons. The basis sets are constructed for use with the previously published small-core relativistic pseudopotentials of the Stuttgart-Cologne variety. Benchmark explicitly correlated coupled-cluster singles and doubles with perturbative triples [CCSD(T)-F12b] calculations of the spectroscopic properties of numerous diatomic molecules involving 4p, 5p, and 6p elements have been carried out and compared to the analogous conventional CCSD(T) results. In general the F12 results obtained with a n-zeta F12 basis set were comparable to conventional aug-cc-pVxZ-PP or aug-cc-pwCVxZ-PP basis set calculations obtained with x = n + 1 or even x = n + 2. The new sets used in CCSD(T)-F12b calculations are particularly efficient at accurately recovering the large correlation effects of the outer-core d electrons.

  15. Methods for forming group III-arsenide-nitride semiconductor materials

    NASA Technical Reports Server (NTRS)

    Major, Jo S. (Inventor); Welch, David F. (Inventor); Scifres, Donald R. (Inventor)

    2002-01-01

    Methods are disclosed for forming Group III-arsenide-nitride semiconductor materials. Group III elements are combined with group V elements, including at least nitrogen and arsenic, in concentrations chosen to lattice match commercially available crystalline substrates. Epitaxial growth of these III-V crystals results in direct bandgap materials, which can be used in applications such as light emitting diodes and lasers. Varying the concentrations of the elements in the III-V crystals varies the bandgaps, such that materials emitting light spanning the visible spectra, as well as mid-IR and near-UV emitters, can be created. Conversely, such material can be used to create devices that acquire light and convert the light to electricity, for applications such as full color photodetectors and solar energy collectors. The growth of the III-V crystals can be accomplished by growing thin layers of elements or compounds in sequences that result in the overall lattice match and bandgap desired.

  16. Total L-shell X-ray production cross sections by 400-700 keV proton impact for elements with 34 < or = Z < or = 53.

    PubMed

    Miranda, J; Ledesma, R; de Lucio, O G

    2001-03-01

    Total L-shell X-ray production cross sections induced by protons with energies between 400 and 700 keV were measured for elements with atomic number Z between 34 and 53. The ECPSSR theory describes appropriately the results. This model modifies the plane wave born approximation by considering projectile energy loss (E), Coulomb deflection of the incoming ion (C), polarization and change in electron binding energies through a perturbed stationary states method (PSS) and relativistic values of target electron mass (R). A comparison is given with previously published data for proton energies below 1 MeV and 26 < or = Z < or = 53, based on a scaling obtained from a reduced velocity parameter zeta(L)R. The results show that the scaling for these atomic numbers and energy ranges is adequate and a semi-empirical expression to calculate those cross sections is proposed. PMID:11214881

  17. First principles DFT study of ferromagnetism in SnO{sub 2} induced by doped group 1A and 2A non-magnetic elements X (X=Li, Na, K, Be, Mg, Ca)

    SciTech Connect

    Chakraborty, Brahmananda Ramaniah, Lavanya M.

    2014-04-24

    Transition metal - free - ferromagnetism in diluted magnetic semiconductors (DMS) is of much current interest in the search for more efficient DMS materials for spintronic applications. Here, we report the results of our first principles density functional theory (DFT) study on impurity - induced ferromagnetism in non-magnetic SnO{sub 2} by a non-magnetic impurity. The impurities considered are sp-type of group 1A and 2A elements X (X = Li, Na, K, Be, Mg, Ca). Even a single atom of the group 1A elements makes the system magnetic, whereas for the group 2A elements Ca and Mg, a higher doping is required to induce ferromagnetism. For all the elements studied, the magnetic moment appears to increase with the doping concentration, at least at certain impurity separations, which is a positive indicator for practical applications.

  18. Cathodoluminescence zoning and minor elements in forsterites from the Murchison (C2) and Allende (C3V) carbonaceous chondrites

    NASA Technical Reports Server (NTRS)

    Steele, I. M.; Smith, J. V.; Skirius, C.

    1985-01-01

    Cathodoluminescence has been applied to look for textural features of olivine in carbonaceous meteorites relevant to the unresolved dispute over the origin of the olivine, whether from a vapor or a liquid. Cathodoluminescence photographs of forsterite grains in Murchison (C2) and Allende (C3) meteorites presented here reveal a blue core with planar boundaries to a red or dark rim. High-precision electron microprobe analyses have been performed which reveal unusually large amounts of the 'minor' elements Al, Ti, and Ca in the blue cores of these forsterites, suggesting formation by crystallization at high temperatures from a source rich in these metals. Following conclusions drawn from previous analyses of olivine in meteorites, it is argued that the minor element signature should be able to characterize olivines in micrometeorites and in deep-sea particles.

  19. Platinum-group element signatures in the North Atlantic Igneous Province: Implications for mantle controls on metal budgets during continental breakup

    NASA Astrophysics Data System (ADS)

    Hughes, Hannah S. R.; McDonald, Iain; Kerr, Andrew C.

    2015-09-01

    The North Atlantic Igneous Province (NAIP) is a large igneous province (LIP) that includes a series of lava suites erupted from the earliest manifestations of the (proto)-Icelandic plume, through continental rifting and ultimate ocean opening. The lavas of one of these sub-provinces, the British Palaeogene Igneous Province (BPIP), were some of the first lavas to be erupted in the NAIP and overlie a thick crustal basement and sedimentary succession with abundant S-rich mudrocks. We present the first platinum-group element (PGE) and Au analyses of BPIP flood basalts from the main lava fields of the Isle of Mull and Morvern and the Isle of Skye, in addition to a suite of shallow crustal dolerite volcanic plugs on Mull, and other minor lavas suites. BPIP lavas display both S-saturated and S-undersaturated trends which, coupled with elevated PGE abundances (> MORB), suggest that the BPIP is one of the most prospective areas of the NAIP to host Ni-Cu-PGE-(Au) mineralisation in conduit systems. Platinum-group element, Au and chalcophile element abundances in lavas from West and East Greenland, and Iceland, are directly comparable to BPIP lavas, but the relative abundances of Pt and Pd vary systematically between lavas suites of different ages. The oldest lavas (BPIP and West Greenland) have a broadly chondritic Pt/Pd ratio (~ 1.9). Lavas from East Greenland have a lower Pt/Pd ratio (~ 0.8) and the youngest lavas from Iceland have the lowest Pt/Pd ratio of the NAIP (~ 0.4). Hence, Pt/Pd ratio of otherwise equivalent flood basalt lavas varies temporally across the NAIP and appears to be coincident with the changing geodynamic environment of the (proto)-Icelandic plume through time. We assess the possible causes for such systematic Pt/Pd variation in light of mantle plume and lithospheric controls, and suggest that this reflects a change in the availability of lithospheric mantle Pt-rich sulphides for entrainment in ascending plume magmas. Hence the precious metal systematics and potential prospectivity of a LIP may be affected by contamination of plume-derived magmas by subcontinental lithospheric mantle at the margins of cratons that have been enriched by Palaeoproterozoic orogenesis.

  20. Ectomycorrhizal Influence on Particle Size, Surface Structure, Mineral Crystallinity, Functional Groups, and Elemental Composition of Soil Colloids from Different Soil Origins

    PubMed Central

    Li, Yanhong; Wang, Huimei; Wang, Wenjie; Yang, Lei; Zu, Yuangang

    2013-01-01

    Limited data are available on the ectomycorrhizae-induced changes in surface structure and composition of soil colloids, the most active portion in soil matrix, although such data may benefit the understanding of mycorrhizal-aided soil improvements. By using ectomycorrhizae (Gomphidius viscidus) and soil colloids from dark brown forest soil (a good loam) and saline-alkali soil (heavily degraded soil), we tried to approach the changes here. For the good loam either from the surface or deep soils, the fungus treatment induced physical absorption of covering materials on colloid surface with nonsignificant increases in soil particle size (P > 0.05). These increased the amount of variable functional groups (O–H stretching and bending, C–H stretching, C=O stretching, etc.) by 3–26% and the crystallinity of variable soil minerals (kaolinite, hydromica, and quartz) by 40–300%. However, the fungus treatment of saline-alkali soil obviously differed from the dark brown forest soil. There were 12–35% decreases in most functional groups, 15–55% decreases in crystallinity of most soil minerals but general increases in their grain size, and significant increases in soil particle size (P < 0.05). These different responses sharply decreased element ratios (C?:?O, C?:?N, and C?:?Si) in soil colloids from saline-alkali soil, moving them close to those of the good loam of dark brown forest soil. PMID:23766704

  1. Uncertainty Principles for Compact Groups

    E-print Network

    Gorjan Alagic; Alexander Russell

    2008-08-29

    We establish an operator-theoretic uncertainty principle over arbitrary compact groups, generalizing several previous results. As a consequence, we show that if f is in L^2(G), then the product of the measures of the supports of f and its Fourier transform ^f is at least 1; here, the dual measure is given by the sum, over all irreducible representations V, of d_V rank(^f(V)). For finite groups, our principle implies the following: if P and R are projection operators on the group algebra C[G] such that P commutes with projection onto each group element, and R commutes with left multiplication, then the squared operator norm of PR is at most rank(P)rank(R)/|G|.

  2. Relatively Long-Lived Dubnium Isotopes and Chemical Identification of Superheavy Elements

    NASA Astrophysics Data System (ADS)

    Tereshatov, E. E.; Bruchertseifer, H.; Voronyuk, M. G.; Starodub, G. Ya.; Petrushkin, O. V.; Dmitriev, S. N.

    2010-04-01

    The present study has been performed within the framework of experiments aimed at the investigation of chemical properties of long-lived Db isotopes in aqueous solutions. The isocratic anion exchange separations of group V elements in the solutions containing HF have been considered. Parameters of separation of dubnium homologues (Pa, Nb and Ta) in HF/HNO3 mixed solutions have been optimized. The procedure of separation of group V elements from multicomponent system has been suggested.

  3. Relatively Long-Lived Dubnium Isotopes and Chemical Identification of Superheavy Elements

    SciTech Connect

    Tereshatov, E. E.; Voronyuk, M. G.; Starodub, G. Ya.; Petrushkin, O. V.; Dmitriev, S. N.; Bruchertseifer, H.

    2010-04-30

    The present study has been performed within the framework of experiments aimed at the investigation of chemical properties of long-lived Db isotopes in aqueous solutions. The isocratic anion exchange separations of group V elements in the solutions containing HF have been considered. Parameters of separation of dubnium homologues (Pa, Nb and Ta) in HF/HNO{sub 3} mixed solutions have been optimized. The procedure of separation of group V elements from multicomponent system has been suggested.

  4. Reactor-scale profile of group-V composition of InGaAsP studied by fluid dynamics simulation and in situ analysis of surface kinetics

    NASA Astrophysics Data System (ADS)

    Onitsuka, Ryusuke; Sugiyama, Masakazu; Shimogaki, Yukihiro; Nakano, Yoshiaki

    2008-06-01

    Reactor-scale simulation of metalorganic vapor phase epitaxy (MOVPE) by computational fluid dynamics is now widely attempted, but it is still difficult to predict group V composition precisely for InGaAsP. In this study, desorption of As and P from the surface of GaAs, InAs, GaP, InP, InGaAs and InGaP was measured around growth temperatures using in situ reflectance anisotropy (RA) spectroscopy. Time transient curves of RA were measured when group V supply was turned on/off and the rate constants of the desorption of As and P were measured assuming first-order kinetics. These data were incorporated into the simulation to obtain the composition of InGaAsP. The simulated distribution of group V composition showed better agreement with experimental data than the results using previous kinetic data.

  5. Efficient and Accurate Identification of Platinum-Group Minerals by a Combination of Mineral Liberation and Electron Probe Microanalysis with a New Approach to the Offline Overlap Correction of Platinum-Group Element Concentrations.

    PubMed

    Osbahr, Inga; Krause, Joachim; Bachmann, Kai; Gutzmer, Jens

    2015-10-01

    Identification and accurate characterization of platinum-group minerals (PGMs) is usually a very cumbersome procedure due to their small grain size (typically below 10 µm) and inconspicuous appearance under reflected light. A novel strategy for finding PGMs and quantifying their composition was developed. It combines a mineral liberation analyzer (MLA), a point logging system, and electron probe microanalysis (EPMA). As a first step, the PGMs are identified using the MLA. Grains identified as PGMs are then marked and coordinates recorded and transferred to the EPMA. Case studies illustrate that the combination of MLA, point logging, and EPMA results in the identification of a significantly higher number of PGM grains than reflected light microscopy. Analysis of PGMs by EPMA requires considerable effort due to the often significant overlaps between the X-ray spectra of almost all platinum-group and associated elements. X-ray lines suitable for quantitative analysis need to be carefully selected. As peak overlaps cannot be avoided completely, an offline overlap correction based on weight proportions has been developed. Results obtained with the procedure proposed in this study attain acceptable totals and atomic proportions, indicating that the applied corrections are appropriate. PMID:26428438

  6. Tables of x-ray mass attenuation coefficients and mass energy-absorption coefficients 1 keV to 20 meV for elements z = 1 to 92 and 48 additional substances of dosimetric interest

    SciTech Connect

    Hubbell, J.H.; Seltzer, S.M.

    1995-05-01

    Tables and graphs of the photon mass attenuation coefficient mu/rho and the mass energy-absorption coefficient mu(en)/rho are presented for all of the elements Z=1 to 92, and for 48 compounds and mixtures of radiological interest. The tables cover energies of the photon (x ray, gamma ray, bremsstrahlung) from 1 keV to 20 MeV. The mu/rho values are taken from the current photon interaction database at the National Institute of Standards and Technology, and the mu(en)/rho values are based on the new calculations by Seltzer described in Radiation Research. These tables of mu/rho and mu(en)/rho replace and extend the tables given by Hubbell in the International Journal of Applied Radiation and Isotopes.

  7. Cosmic-ray elemental abundances from 1 to 10 GeV per amu for boron through nickel

    NASA Technical Reports Server (NTRS)

    Dwyer, Robert; Meyer, Peter

    1987-01-01

    The relative abundances of cosmic-ray nuclei in the charge range boron through nickel over the energy range 1-10 GeV per amu were measured with a balloon-borne detector. The instrument consists of a scintillation and Cerenkov counter telescope with a multiwire proportional chamber hodoscope and has been flown in four high-altitude balloon flights. Good charge resolution (sigma = 0.2 charge units at iron) and high statistical accuracy have been achieved. These data are used to derive the energy dependence of the leakage path length using the leaky box model of propagation and confinement in the galaxy. This energy dependence is found to be best fit by lambda = E(tot) exp -n, where n = 0.49 + or - 0.06 over 1-10 GeV per amu. Relative abundances at the source are consistent with an energy-independent composition.

  8. A multicenter, double-blind comparison of i.v. and oral administration of ondansetron plus dexamethasone for acute cisplatin-induced emesis. Ondansetron Acute Emesis Study Group.

    PubMed

    Krzakowski, M; Graham, E; Goedhals, L; Joly, F; Pawlicki, M; Rapoport, B; Yelle, L; Lees, J; McQuade, B

    1998-08-01

    A total of 530 patients were treated in this multicenter, double-blind, double-dummy, parallel group study to compare the anti-emetic efficacy and safety of a once daily ondansetron oral regimen with a once daily i.v. dosing regimen over a 24 h period, administered to patients prior to receiving cisplatin (50 mg/m2 or greater) chemotherapy. Patients were randomized to receive a single dose of ondansetron plus dexamethasone given either orally (ondansetron 24 mg and dexamethasone 12 mg, n=262) or i.v. (ondansetron 8 mg and dexamethasone 20 mg, n=268). Complete control of emesis (i.e. no emetic episodes, no rescue and no premature withdrawal) was achieved for 85% of patients (224 of 262) in the oral group and 83% (223 of 268) in the i.v. group. No nausea was reported in 70% of patients in the oral group and 68% in the i.v. group. There were no statistically significant differences between the two groups for any of the assessments of efficacy, which included time to first emetic episode, number of emetic episodes and the worst grade of nausea occurring over the 24 h study period. Once daily ondansetron oral and i.v., in combination with dexamethasone, was well tolerated in this study. In conclusion, once daily oral ondansetron 24 mg plus dexamethasone is equally effective in the control of emesis and nausea induced by highly emetogenic chemotherapy as once daily ondansetron 8 mg i.v. plus dexamethasone. PMID:9773802

  9. Molecular characterization of Hor v 9. Conservation of a T-cell epitope among group IX pollen allergens and human VCAM and CD2.

    PubMed

    Astwood, J D; Hill, R D

    1996-01-01

    We have cloned, sequenced and expressed a recombinant group IX pollen allergen from barley (Hordeum vulgare). Hor v 9 is a polypeptide of 313 amino acids. The Hor v 9 cDNA clone was engineered into the E. coli protein expression vector pMAL and expressed as a fusion of maltose binding protein and truncated Hor v 9. Polyclonal antibodies to the fusion protein were raised in mice. Cross-reactive proteins, RNA and DNA homologues were found in many agricultural species including wheat, rye, triticale, oats, maize, sunflower and flax. The presence of group IX-like proteins in a variety of agricultural crops may represent a previously uncharacterized aeroallergenic occupational hazard. Sequence comparisons of the barley allergen, Hor v 9, with Poa p 9 and other cloned group IX pollen allergens revealed putative structural domains common to all. These include a signal peptide, two conserved immunoglobulin-like motifs, a 150 amino acid highly conserved carboxyterminal domain and a carboxyterminal transmembrane helix. This structural arrangement is also found in cell adhesion molecules. The highly conserved T-cell epitope previously characterized and mapped in group IX allergens (and present in Hor v 9) was found in several human cell adhesion molecule sequences (VCAM, NCAM and CD2). This T-cell epitope corresponded to the most highly conserved amino acid residues common to all group IX homologues sequenced to date. CD2 and VCAM are known to play a role in allergic inflammation: VCAM is involved in the recruitment of lymphocytes to sites of inflammation, and cross-linking CD2 leads to T-cell activation. We anticipate that the similar structural arrangement of group IX allergens and human cell adhesion molecules, as well as the presence of a T-cell epitope common to group IX pollen allergens and cell adhesion molecules, will have important consequences in the natural history of the atopic immune response. PMID:9095254

  10. Effects of mother lode-type gold mineralization on 187Os/188Os and platinum group element concentrations in peridotite: Alleghany District, California

    USGS Publications Warehouse

    Walker, R.J.; Böhlke, J.K.; McDonough, W.F.; Li, J.

    2007-01-01

    Osmium isotope compositions and concentrations of Re, platinum group elements (PGE), and Au were determined for host peridotites (serpentinites and barzburgites) and hydrothermally altered ultramafic wall rocks associated with Mother Lode-type hydrothermal gold-quartz vein mineralization in the Alleghany district, California. The host peridotites have Os isotope compositions and Re, PGE, and Au abundances typical of the upper mantle at their presumed formation age during the late Proterozoic or early Paleozoic. The hydrothermally altered rocks have highly variable initial Os isotope compositions with ??os, values (% deviation of 187OS/188OS from the chondritic average calculated for the approx. 120 Ma time of mineralization) ranging from -1.4 to -8.3. The lowest Os isotope compositions are consistent with Re depletion of a chondritic source (e.g., the upper mantle) at ca. 1.6 Ga. Most of the altered samples are enriched in Au and have depleted and fractionated abundances of Re and PGE relative to their precursor peridotites. Geoehemical characteristics of the altered samples suggest that Re and some PGE were variably removed from the ultramafic rocks during the mineralization event. In addition to Re, the Pt and Pd abundances of the most intensely altered rocks appear to have been most affected by mineralization. The 187Os-depleted isotopic compositions of some altered rocks are interpreted to be a result of preferential 187Os loss via destruction of Re-rich phases during the event. For these rocks, Os evidently is not a useful tracer of the mineralizing fluids. The results do, however, provide evidence for differential mobility of these elements, and mobility of 187Os relative to the initial bulk Os isotope composition during hydrothermal metasomatic alteration of ultramafic rocks. ?? 2007 Society of Economic Geologists, Inc.

  11. First-principles electronic structure and formation energies of group V and VII impurities in the ?-Fe{sub 2}O{sub 3} alloys

    SciTech Connect

    Xia, Congxin; Jia, Yu; Zhang, Qiming

    2014-09-21

    Based on density functional theory, the electronic structures, formation energy, and transition level of the selected group V and VII impurities in ?-Fe{sub 2}O{sub 3} are investigated by means of first-principles methods. Numerical results show that the group V and VII atoms-doped ?-Fe{sub 2}O{sub 3} can be energetically favorable under the Fe-rich condition. Group V atom substituting O atom can induce the acceptor impurity level, while the deep donor impurity states are formed inside the band gap when group VII atom substitute O atom in the ?-Fe{sub 2}O{sub 3}. Moreover, our results show that halogen atom F substituting O atom should be very easy in the ?-Fe{sub 2}O{sub 3}. In addition, our results also show that for both group V and VII atom-doped ?-Fe{sub 2}O{sub 3}, the upper sides of valence band are modified obviously, while the conduction band edge does not change.

  12. Understanding the On-Off Switching Mechanism in Cationic Tetravalent Group-V-Based Fluoride Molecular Sensors Using Orbital Analysis.

    PubMed

    Usui, Kosuke; Ando, Mikinori; Yokogawa, Daisuke; Irle, Stephan

    2015-12-24

    The precise control of on-off switching is essential to the design of ideal molecular sensors. To understand the switching mechanism theoretically, we selected as representative example a 9-anthryltriphenylstibonium cation, which was reported as a fluoride ion sensor. In this molecule, the first excited singlet state exhibits two minimum geometries, where one of them is emissive and the other one dark. The excited state at the geometry with bright emission is of ?-?* character, whereas it is of ?-?* character at the "dark" geometry. Geometry changes in the excited state were identified by geometry optimization and partial potential energy surface (PES) mapping. We also studied Group V homologues of this molecule. A barrierless relaxation pathway after vertical excitation to the "dark" geometry was found for the Sb-containing compound on the excited-states PES, whereas barriers appear in the case of P and As. Molecular orbital analysis suggests that the ?* orbital of the antimony compound is stabilized along such relaxation and that the excited state changes its nature correspondingly. Our results indicate that the size of the central atom is crucial for the design of fluoride sensors with this ligand framework. PMID:26647787

  13. Platinum-group element (PGE) geochemistry of Mesoarchean ultramafic-mafic cumulate rocks and chromitites from the Nuasahi Massif, Singhbhum Craton (India)

    NASA Astrophysics Data System (ADS)

    Khatun, Sarifa; Mondal, Sisir K.; Zhou, Mei-Fu; Balaram, Vysetti; Prichard, Hazel M.

    2014-09-01

    The Mesoarchean Nuasahi Massif in eastern India comprises a lower ultramafic and an upper gabbro unit. The lower unit consists of orthopyroxenite, harzburgite, dunite and three chromitite bands. All of these rocks are characterized by adcumulate textures. The upper unit consists of gabbro with magnetite layers. At the contact between the eastern orthopyroxenite and the lower part of the upper gabbro, a sulfide-rich breccia zone with platinum-group-element (PGE) mineralization is present. Detailed studies of major-, trace- and PGE abundances suggest that the ultramafic-mafic cumulate rocks, chromitites and breccias are genetically linked. The chondrite-normalized U-shaped rare earth element (REE) patterns of the harzburgite resemble those of Phanerozoic boninite. The overall U-shaped REE patterns of the ultramafic rocks indicate derivation of the parental magma from a metasomatized depleted mantle source. The upper gabbros have higher relative abundances of trace elements than the lower ultramafic rocks, due to crystallization from a fractionated magma. Whole-rock geochemistry suggests that the lower ultramafic cumulate rocks with chromitites crystallized from a boninitic parental magma, whereas the upper gabbros with magnetite bands may be formed from residual boninitic magma that was contaminated by more tholeiitic-like magmas. The boninitic parental magma that crystallized to form the lower ultramafic unit was most likely generated by second-stage melting of a depleted metasomatized mantle source in a supra-subduction zone (SSZ) setting and emplaced into crustal sequences. The PGE abundances in the Nuasahi rocks provide additional constraints on their geochemical evolution during the Mesoarchean. Primitive-mantle-normalized PGE diagrams show (1) Ru enrichment in chromitites (Pd/Ru = 0.17-0.64), (2) Pd/Pt fractionation in both chromitites (Pd/Pt = 3.1) and ultramafic rocks (Pd/Pt = 0.62), (3) marked Ir depletion in ultramafic rocks (Pd/Ir = 6.3) and (4) overall PGE enrichment in chromitites (PGEtotal = 142-502 ppb). The large Ir depletion in the ultramafic rocks, and the overall Ir-depleted character of other rocks from the Nuasahi Massif, may be related to multiple episodes of melt extraction from the mantle source, giving it a subchondritic character.

  14. Top quark mass measurement in the tt all hadronic channel using a matrix element technique in pp collisions at {radical}(s)=1.96 TeV

    SciTech Connect

    Aaltonen, T.; Maki, T.; Mehtala, P.; Orava, R.; Remortel, N. van; Adelman, J.; Brubaker, E.; Fedorko, W. T.; Grosso-Pilcher, C.; Kim, Y. K.; Krop, D.; Kwang, S.; Lee, H. S.; Paramonov, A. A.; Schmidt, M. A.; Shiraishi, S.; Shochet, M.; Wilbur, S.; Wolfe, C.; Yang, U. K.

    2009-04-01

    We present a measurement of the top quark mass in the all hadronic channel (tt{yields}bbq{sub 1}q{sub 2}q{sub 3}q{sub 4}) using 943 pb{sup -1} of pp collisions at {radical}(s)=1.96 TeV collected at the CDF II detector at Fermilab (CDF). We apply the standard model production and decay matrix element (ME) to tt candidate events. We calculate per-event probability densities according to the ME calculation and construct template models of signal and background. The scale of the jet energy is calibrated using additional templates formed with the invariant mass of pairs of jets. These templates form an overall likelihood function that depends on the top quark mass and on the jet energy scale (JES). We estimate both by maximizing this function. Given 72 observed events, we measure a top quark mass of 171.1{+-}3.7(stat+JES){+-}2.1(syst) GeV/c{sup 2}. The combined uncertainty on the top quark mass is 4.3 GeV/c{sup 2}.

  15. Revised Energy Spectra for Primary Elements, H - Si, above 50 GeV from the ATIC-2 Science Flight

    NASA Technical Reports Server (NTRS)

    Wefel, J. P.; Adams, J. H., Jr.; Ahn, H. S.; Bashindzhagyan, G. L.; Chang, J.; Christl, M.; Fazely, A. R.; Ganel, O.; Gunashingha, R. M.; Guzik, T. G.; Isbert, J.; Kim, K. C.; Kouznetsov, E. N.; Panasyuk, M. I.; Panov, A. D.; Schmidt, W. K. H.; Seo, E. S.; Sokolskaya, N. V.; Watts, J. W.; Wu, J.; Zatsepin, V. I.

    2007-01-01

    The Advanced Thin Ionization Calorimeter (ATIC) long duration balloon experiment had a successful science flight accumulating 18 days of data (12/02 - 1/03) during a single circumnavigation in Antarctica. ATIC measures the energy spectra of elements from H to Fe in primary cosmic rays using a fully active Bismuth Germanate calorimeter preceded by a carbon target, with embedded scintillator hodoscopes, and a silicon matrix charge detector at the top. Preliminary results from ATIC have been reported in previous conferences. The revised results reported here are derived from a new analysis of the data with improved charge resolution, lower background and revised energy calibration. The raw energy deposit spectra are de-convolved into primary energy spectra and extrapolated to the top of the atmosphere. We compare these revised results to previous data and comment upon the astrophysical interpretation of the results.

  16. Determination of the platinum - Group elements (PGE) and gold (Au) in manganese nodule reference samples by nickel sulfide fire-assay and Te coprecipitation with ICP-MS

    USGS Publications Warehouse

    Balaram, V.; Mathur, R.; Banakar, V.K.; Hein, J.R.; Rao, C.R.M.; Gnaneswara, Rao T.; Dasaram, B.

    2006-01-01

    Platinum group elements (PGE) and Au data in polymetallic oceanic ferromanganese nodule reference samples and crust samples obtained by inductively coupled plasma mass spectrometry (ICP-MS), after separation and pre-concentration by nickel sulfide fire-assay and Te coprecipitation, are presented. By optimizing several critical parameters such as flux composition, matrix matching calibration, etc., best experimental conditions were established to develop a method suitable for routine analysis of manganese nodule samples for PGE and Au. Calibrations were performed using international PGE reference materials, WMG-1 and WMS-1. This improved procedure offers extremely low detection limits in the range of 0.004 to 0.016 ng/g. The results obtained in this study for the reference materials compare well with previously published data wherever available. New PGE data arc also provided on some international manganese nodule reference materials. The analytical methodology described here can be used for the routine analysis of manganese nodule and crust samples in marine geochemical studies.

  17. Systematically convergent basis sets with relativistic pseudopotentials. II. Small-core pseudopotentials and correlation consistent basis sets for the post-d group 16-18 elements

    SciTech Connect

    Peterson, Kirk A.; Figgen, Detlev; Goll, Erich; Stoll, Hermann; Dolg, Michael F.

    2003-12-01

    Series of correlation consistent basis sets have been developed for the post-d group 16-18 elements in conjunction with small-core relativistic pseudopotentials (PPs) of the energy-consistent variety. The latter were adjusted to multiconfiguration Dirac-Hartree-Fock data based on the Dirac-Coulomb-Breit Hamiltonian. The outer-core (n-1)spd shells are explicitly treated together with the nsp valence shell with these PPs. The accompanying cc-pVnZ-PP and aug-cc-pVnZ-PP basis sets range in size from DZ to 5Z quality and yield systematic convergence of both Hartree-Fock and correlated total energies. In addition to the calculation of atomic electron affinities and dipole polarizabilities of the rare gas atoms, numerous molecular benchmark calculations (HBr, HI, HAt, Br2, I2, At2, SiSe, SiTe, SiPo, KrH+, XeH+, and RnH+) are also reported at the coupled cluster level of theory. For the purposes of comparison, all-electron calculations using the Douglas-Kroll-Hess Hamiltonian have also been carried out for the halogen-containing molecules using basis sets of 5Z quality.

  18. ENVIRONMENTAL TECHNOLOGY VERIFICATION, TEST REPORT OF CONTROL OF BIOAEROSOLS IN HVAC SYSTEMS, FILTRATION GROUP, AEROSTAR FP-98 MINIPLEAT V-BLANK FILTER

    EPA Science Inventory

    The Environmental Technology Verification report discusses the technology and performance of the AeroStar FP-98 Minipleat V-Bank Filter air filter for dust and bioaerosol filtration manufactured by Filtration Group. The pressure drop across the filter was 137 Pa clean and 348 Pa ...

  19. An Alaska fur seal family on St. Paul Island, Pribilof Group, Alaska . (Photo: V.B . Scheffe SEC. STANS REPORTS FAVORABLY ON

    E-print Network

    IV An Alaska fur seal family on St. Paul Island, Pribilof Group, Alaska . (Photo: V.B . Scheffe #12;SEC. STANS REPORTS FAVORABLY ON SEAL HARVESTING IN PRIBILOF ISLANDS Secretary of Commerce Maurice H. Stans 1 eported, July 14, 1971, his conclusions on ethods used to harvest seals after a visit to he

  20. A fur seal family on St. Paul Island, Pribilof Group, Alaska. (Photo: V. B. Scheffer) MEASURING MORTALITY OF FUR-SEAL PUPS

    E-print Network

    28 A fur seal family on St. Paul Island, Pribilof Group, Alaska. (Photo: V. B. Scheffer) #12;MEASURING MORTALITY OF FUR-SEAL PUPS IS IMPORTANT TO MANAGEMENT OF HERDS About a million n orthern fur seal. Forty to 50 thousand fur seals are harve sted a nnually for their furs. By agre ement, the s e

  1. Muon groups and primary composition at 10 to the 13th power to 10 to the 15th power eV

    NASA Technical Reports Server (NTRS)

    Budko, E. V.; Chudakov, A. E.; Dogujaev, V. A.; Mihelev, A. R.; Padey, V. A.; Petkov, V. A.; Striganov, P. S.; Suvorova, O. V.; Voevodsky, A. V.

    1985-01-01

    The data on muon groups observed at Baksan underground scintillation telescope is analyzed. In this analysis we compare the experimental data with calulations, based on a superposition model in order to obtain the effective atomic number of primary cosmic rays in the energy range 10 to the 13th power to 10 to the 15th power eV.

  2. 75 FR 45623 - Morris Energy Group, LLC v.PSEG Energy Resources & Trade LLC; PSEG Fossil LLC; and PSEG Power LLC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-03

    ... From the Federal Register Online via the Government Printing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Morris Energy Group, LLC v.PSEG Energy Resources & Trade LLC; PSEG Fossil..., LLC, PSEG Fossil LLC and PSEG Power LLC (PSEG Power Companies) (Respondents), requesting that...

  3. 76 FR 46793 - PJM Interconnection, L.L.C.; PJM Power Providers Group v. PJM Interconnection, L.L.C.; Notice...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-03

    ...ER11-2875-001; ER11-2875-002; Docket No. EL11-20-001] PJM Interconnection, L.L.C.; PJM Power Providers Group v. PJM Interconnection, L.L.C.; Notice Establishing Post-Technical Comment Period As indicated in the...

  4. Coupled Transient Finite Element Simulation of Quench in Jefferson Lab's 11 GeV Super High Momentum Spectrometer Superconducting Magnets

    SciTech Connect

    E. Sun, P. Brindza, S. Lassiter, M. Fowler, E. Xu

    2010-06-01

    This paper presents coupled transient thermal and electromagnetic finite element analysis of quench in the Q2, Q3, and dipole superconducting magnets using Vector Fields Quench code. Detailed temperature distribution within coils and aluminum force collars were computed at each time step. Both normal (quench with dump resistor) and worst-case (quench without dump resistor) scenarios were simulated to investigate the maximum temperatures. Two simulation methods were utilized, and their algorithms, implementation, advantages, and disadvantages are discussed. The first method simulated the coil using nonlinear transient thermal analysis directly linked with the transient circuit analysis. It was faster because only the coil was meshed and no eddy current was modeled. The second method simulated the whole magnet including the coil, the force collar, and the iron yoke. It coupled thermal analysis with transient electromagnetic field analysis which modeled electromagnetic fields including eddy currents within the force collar. Since eddy currents and temperature in the force collars were calculated in various configurations, segmentation of the force collars was optimized under the condition of fast discharge.

  5. Dabrafenib for Treating Unresectable, Advanced or Metastatic BRAF V600 Mutation-Positive Melanoma: An Evidence Review Group Perspective.

    PubMed

    Fleeman, Nigel; Bagust, Adrian; Beale, Sophie; Boland, Angela; Dickson, Rumona; Dwan, Kerry; Richardson, Marty; Dundar, Yenal; Davis, Helen; Banks, Lindsay

    2015-09-01

    The National Institute for Health and Care Excellence (NICE) invited GlaxoSmithKline, the manufacturer of dabrafenib, to submit evidence for the clinical and cost effectiveness of dabrafenib for the treatment of unresectable, advanced or metastatic BRAF V600 mutation-positive melanoma in accordance with the Institute's Single Technology Appraisal (STA) process. The Liverpool Reviews and Implementation Group (LRiG) at the University of Liverpool was commissioned to act as the Evidence Review Group (ERG). This article summarizes the ERG's review of the evidence submitted by the company and provides a summary of the Appraisal Committee's (AC) final decision in October 2014. The clinical evidence for dabrafenib was derived from an ongoing phase III, randomized, double-blind, placebo-controlled, international, multicentre clinical trial (BREAK-3) involving 230 patients randomized 2:1 to receive either dabrafenib or dacarbazine. A significant improvement in median progression-free survival (PFS) but not overall survival (OS) was reported in the dabrafenib arm compared with dacarbazine. Vemurafenib is considered a more appropriate comparator than is dacarbazine. The clinical evidence for vemurafenib was derived from a completed phase III, randomized, double-blind, placebo-controlled, international, multicentre clinical trial (BRIM-3) involving 675 patients randomized 1:1 to receive either vemurafenib or dacarbazine. A significant improvement in median PFS and OS was reported in the vemurafenib arm compared with dacarbazine. As there is no direct evidence comparing dabrafenib versus vemurafenib, the company presented an indirect treatment comparison (ITC) that demonstrated no statistical differences between dabrafenib and vemurafenib for PFS or OS. The ERG expressed concerns with the ITC, mainly in relation to the validity of the assumptions underpinning the methodology; the ERG concluded this resulted in findings that are unlikely to be robust or reliable. Dabrafenib and vemurafenib are both available to patients treated by the National Health Service (NHS) in England via a Patient Access Scheme (PAS) in which the costs of the drugs are discounted. Using these discounted costs, the incremental cost-effectiveness ratios (ICERs) generated by the company were £60,980 per quality-adjusted life-year (QALY) for dabrafenib versus dacarbazine and £11,046 per QALY gained for dabrafenib versus vemurafenib. The ERG considered the economic model structure developed by the company to derive the ICERs to be overly complex and based on unsubstantiated assumptions, most importantly in relation to the projection of OS. Applying the latest OS data from BREAK-3 to a less complex model structure increased the estimated ICER for dabrafenib compared with dacarbazine from £60,980 to £112,727 per QALY gained. Since the results from the ITC were considered by the ERG to be neither reliable nor robust, the ERG also considered a cost-effectiveness comparison to be inappropriate due to a lack of meaningful or reliable data. In spite of limitations in the data, the AC took the view that dabrafenib and vemurafenib were "likely" of similar clinical effectiveness. Since the overall costs of these two drugs were similar, the AC recommended the use of dabrafenib in patients with unresectable, advanced or metastatic BRAF V600 mutation-positive melanoma. PMID:25906420

  6. Ku86 defines the genetic defect and restores X-ray resistance and V(D)J recombination to complementation group 5 hamster cell mutants.

    PubMed Central

    Errami, A; Smider, V; Rathmell, W K; He, D M; Hendrickson, E A; Zdzienicka, M Z; Chu, G

    1996-01-01

    X-ray-sensitive hamster cells in complementation groups 4, 5, 6, and 7 are impaired for both double-strand break repair and V(D)J recombination. Here we show that in two mutant cell lines (XR-V15B and XR-V9B) from group 5, the genetic defects are in the gene encoding the 86-kDa subunit of the Ku autoantigen, a nuclear protein that binds to the double-stranded DNA ends. These mutants express Ku86 mRNA containing deletions of 138 and 252 bp, respectively, and the encoded proteins contain internal, in-frame deletions of 46 and 84 amino acids. Two X-ray-resistant revertants of XR-V15B expressed two Ku86 transcripts, one with and one without the deletion, suggesting that reversion occurred by activation of a silent wild-type allele. Transfection of full-length cDNA encoding hamster Ku86 into XR-V15B cells resulted in a complete rescue of DNA-end-binding (DEB) activity and Ku70 levels, suggesting that Ku86 stabilizes the Ku70 polypeptide. In addition, cells expressing wild-type levels of DEB activity were fully rescued for X-ray resistance and V(D)J recombination, whereas cells expressing lower levels of DEB activity were only partially rescued. Thus, Ku is an essential component of the pathway(s) utilized for the resolution of DNA double-strand breaks induced by either X rays or V(D)J recombination, and mutations in the Ku86 gene are responsible for the phenotype of group 5 cells. PMID:8657125

  7. Braid groups of imprimitive reflection groups

    E-print Network

    Digne, François

    6/5/2012 1 Braid groups of imprimitive reflection groups Ruth Corran Cap Hornu May 30, 2012 Finite complex reflection groups V a vector space over C with dim(V) = r. A complex reflection s is a non) is the reflection hyperplane for the reflection s A (finite) complex reflection group W is a (finite) group

  8. ICEG2D (v2.0) - An Integrated Software Package for Automated Prediction of Flow Fields for Single-Element Airfoils With Ice Accretion

    NASA Technical Reports Server (NTRS)

    Thompson David S.; Soni, Bharat K.

    2001-01-01

    An integrated geometry/grid/simulation software package, ICEG2D, is being developed to automate computational fluid dynamics (CFD) simulations for single- and multi-element airfoils with ice accretions. The current version, ICEG213 (v2.0), was designed to automatically perform four primary functions: (1) generate a grid-ready surface definition based on the geometrical characteristics of the iced airfoil surface, (2) generate high-quality structured and generalized grids starting from a defined surface definition, (3) generate the input and restart files needed to run the structured grid CFD solver NPARC or the generalized grid CFD solver HYBFL2D, and (4) using the flow solutions, generate solution-adaptive grids. ICEG2D (v2.0) can be operated in either a batch mode using a script file or in an interactive mode by entering directives from a command line within a Unix shell. This report summarizes activities completed in the first two years of a three-year research and development program to address automation issues related to CFD simulations for airfoils with ice accretions. As well as describing the technology employed in the software, this document serves as a users manual providing installation and operating instructions. An evaluation of the software is also presented.

  9. Monochromatic X-ray-induced thermal effect on four-reflection “nested” meV-monochromators: dynamical diffraction theory and finite-element analysis

    NASA Astrophysics Data System (ADS)

    Hu, Ling-Fei; Gao, Li-Dan; Li, Zhen-Jie; Wang, Shan-Feng; Sheng, Wei-Fan; Liu, Peng; Xu, Wei

    2015-09-01

    The high energy resolution monochromator (HRM) is widely used in inelastic scattering programs to detect phonons with energy resolution, down to the meV level. Although the large amount of heat from insertion devices can be reduced by a high heat-load monochromator, the unbalanced heat load on the inner pair of crystals in a nested HRM can affect its overall performance. Here, a theoretical analysis of the unbalanced heat load using dynamical diffraction theory and finite element analysis is presented. By utilizing the ray-tracing method, the performance of different HRM nesting configurations is simulated. It is suggested that the heat balance ratio, energy resolution, and overall spectral transmission efficiency are the figures of merit for evaluating the performance of nested HRMs. Although the present study is mainly focused on nested HRMs working at 57Fe nuclear resonant energy at 14.4 keV, it is feasible to extend this to other nested HRMs working at different energies.

  10. arXiv:1207.2227v1[math.AG]10Jul2012 SPORADIC SIMPLE GROUPS AND QUOTIENT SINGULARITIES

    E-print Network

    Cheltsov, Ivan

    sporadic simple group such that some of its faithful rep- resentations or some faithful representations, Theorem 2.1], and [4, Theorem A.3]). Many old and still open group-theoretic questions have algebro

  11. On Some Algebraic and Combinatorial Properties of Dunkl Elements

    NASA Astrophysics Data System (ADS)

    Kirillov, Anatol N.

    2013-06-01

    We introduce and study a certain class of nonhomogeneous quadratic algebras together with the special set of mutually commuting elements inside of each, the so-called Dunkl elements. We describe relations among the Dunkl elements. This result is a further generalization of similar results obtained in [S. Fomin and A. N. Kirillov, Quadratic algebras, Dunkl elements and Schubert calculus, in Advances in Geometry (eds. J.-S. Brylinski, V. Nistor, B. Tsygan and P. Xu), Progress in Math. Vol. 172 (Birkhäuser Boston, Boston, 1995), pp. 147-182, A. Postnikov, On a quantum version of Pieri's formula, in Advances in Geometry (eds. J.-S. Brylinski, R. Brylinski, V. Nistor, B. Tsygan and P. Xu), Progress in Math. Vol. 172 (Birkhäuser Boston, 1995), pp. 371-383 and A. N. Kirillov and T. Maenor, A Note on Quantum K-Theory of Flag Varieties, preprint]. As an application we describe explicitly the set of relations among the Gaudin elements in the group ring of the symmetric group, cf. [E. Mukhin, V. Tarasov and A. Varchenko, Bethe Subalgebras of the Group Algebra of the Symmetric Group, preprint arXiv:1004.4248]. Also we describe a few combinatorial properties of some special elements in the associative quasi-classical Yang-Baxter algebra in a connection with the values of the ?-Grothendieck polynomials for some special permutations, and on the other hand, with the Ehrhart polynomial of the Chan-Robbins polytope.

  12. On Some Algebraic and Combinatorial Properties of Dunkl Elements

    NASA Astrophysics Data System (ADS)

    Kirillov, Anatol N.

    2012-11-01

    We introduce and study a certain class of nonhomogeneous quadratic algebras together with the special set of mutually commuting elements inside of each, the so-called Dunkl elements. We describe relations among the Dunkl elements. This result is a further generalization of similar results obtained in [S. Fomin and A. N. Kirillov, Quadratic algebras, Dunkl elements and Schubert calculus, in Advances in Geometry (eds. J.-S. Brylinski, V. Nistor, B. Tsygan and P. Xu), Progress in Math. Vol. 172 (Birkhäuser Boston, Boston, 1995), pp. 147-182, A. Postnikov, On a quantum version of Pieri's formula, in Advances in Geometry (eds. J.-S. Brylinski, R. Brylinski, V. Nistor, B. Tsygan and P. Xu), Progress in Math. Vol. 172 (Birkhäuser Boston, 1995), pp. 371-383 and A. N. Kirillov and T. Maenor, A Note on Quantum K-Theory of Flag Varieties, preprint]. As an application we describe explicitly the set of relations among the Gaudin elements in the group ring of the symmetric group, cf. [E. Mukhin, V. Tarasov and A. Varchenko, Bethe Subalgebras of the Group Algebra of the Symmetric Group, preprint arXiv:1004.4248]. Also we describe a few combinatorial properties of some special elements in the associative quasi-classical Yang-Baxter algebra in a connection with the values of the ?-Grothendieck polynomials for some special permutations, and on the other hand, with the Ehrhart polynomial of the Chan-Robbins polytope.

  13. Differences in the Activities of Eight Enzymes from Ten Soil Fungi and Their Possible Influences on the Surface Structure, Functional Groups, and Element Composition of Soil Colloids

    PubMed Central

    Wang, Wenjie; Li, Yanhong; Wang, Huimei; Zu, Yuangang

    2014-01-01

    How soil fungi function in soil carbon and nutrient cycling is not well understood by using fungal enzymatic differences and their interactions with soil colloids. Eight extracellular enzymes, EEAs (chitinase, carboxymethyl cellulase, ?-glucosidase, protease, acid phosphatase, polyphenol oxidase, laccase, and guaiacol oxidase) secreted by ten fungi were compared, and then the fungi that showed low and high enzymatic activity were co-cultured with soil colloids for the purpose of finding fungi-soil interactions. Some fungi (Gomphidius rutilus, Russula integra, Pholiota adiposa, and Geastrum mammosum) secreted 3–4 enzymes with weak activities, while others (Cyathus striatus, Suillus granulate, Phallus impudicus, Collybia dryophila, Agaricus sylvicola, and Lactarius deliciosus) could secret over 5 enzymes with high activities. The differences in these fungi contributed to the alterations of functional groups (stretching bands of O-H, N-H, C-H, C?=?O, COO- decreased by 11–60%, while P?=?O, C-O stretching, O-H bending and Si-O-Si stretching increased 9–22%), surface appearance (disappearance of adhesive organic materials), and elemental compositions (11–49% decreases in C1s) in soil colloids. Moreover, more evident changes were generally in high enzymatic fungi (C. striatus) compared with low enzymatic fungi (G. rutilus). Our findings indicate that inter-fungi differences in EEA types and activities might be responsible for physical and chemical changes in soil colloids (the most active component of soil matrix), highlighting the important roles of soil fungi in soil nutrient cycling and functional maintenance. PMID:25398013

  14. Silicon is the closest element to carbon in the PeriodicTable, both belonging to group 14, but, the structural rules, chemical behavior and physical properties of their compounds are very different. These differences

    E-print Network

    Apeloig, Yitzhak

    22 Silicon is the closest element to carbon in the PeriodicTable, both belonging to group 14, but of organic chemistry. In contrast, until the 1970s only transient compounds with double bonds to silicon of other stable silenes and disilenes and of compounds with heteroatom- silicon double bonds (as well

  15. The distribution of platinum group elements (PGE) and other chalcophile elements among sulfides from the Creighton Ni-Cu-PGE sulfide deposit, Sudbury, Canada, and the origin of palladium in pentlandite

    NASA Astrophysics Data System (ADS)

    Dare, Sarah A. S.; Barnes, Sarah-Jane; Prichard, Hazel M.

    2010-12-01

    Concentrations of platinum group elements (PGE), Ag, As, Au, Bi, Cd, Co, Mo, Pb, Re, Sb, Se, Sn, Te, and Zn, have been determined in base metal sulfide (BMS) minerals from the western branch (402 Trough orebodies) of the Creighton Ni-Cu-PGE sulfide deposit, Sudbury, Canada. The sulfide assemblage is dominated by pyrrhotite, with minor pentlandite, chalcopyrite, and pyrite, and they represent monosulfide solid solution (MSS) cumulates. The aim of this study was to establish the distribution of the PGE among the BMS and platinum group minerals (PGM) in order to understand better the petrogenesis of the deposit. Mass balance calculations show that the BMS host all of the Co and Se, a significant proportion (40-90%) of Os, Pd, Ru, Cd, Sn, and Zn, but very little (<35%) of the Ag, Au, Bi, Ir, Mo, Pb, Pt, Rh, Re, Sb, and Te. Osmium and Ru are concentrated in equal proportions in pyrrhotite, pentlandite, and pyrite. Cobalt and Pd (˜1 ppm) are concentrated in pentlandite. Silver, Cd, Sn, Zn, and in rare cases Au and Te, are concentrated in chalcopyrite. Selenium is present in equal proportions in all three BMS. Iridium, Rh, and Pt are present in euhedrally zoned PGE sulfarsenides, which comprise irarsite (IrAsS), hollingworthite (RhAsS), PGE-Ni-rich cobaltite (CoAsS), and subordinate sperrylite (PtAs2), all of which are hosted predominantly in pyrrhotite and pentlandite. Silver, Au, Bi, Mo, Pb, Re, Sb, and Te are found predominantly in discrete accessory minerals such as electrum (Au-Ag alloy), hessite (Ag2Te), michenerite (PdBiTe), and rhenium sulfides. The enrichment of Os, Ru, Ni, and Co in pyrrhotite, pentlandite, and pyrite and Ag, Au, Cd, Sn, Te, and Zn in chalcopyrite can be explained by fractional crystallization of MSS from a sulfide liquid followed by exsolution of the sulfides. The early crystallization of the PGE sulfarsenides from the sulfide melt depleted the MSS in Ir and Rh. The bulk of Pd in pentlandite cannot be explained by sulfide fractionation alone because Pd should have partitioned into the residual Cu-rich liquid and be in chalcopyrite or in PGM around chalcopyrite. The variation of Pd among different pentlandite textures provides evidence that Pd diffuses into pentlandite during its exsolution from MSS. The source of Pd was from the small quantity of Pd that partitioned originally into the MSS and a larger quantity of Pd in the nearby Cu-rich portion (intermediate solid solution and/or Pd-bearing PGM). The source of Pd became depleted during the diffusion process, thus later-forming pentlandite (rims of coarse-granular, veinlets, and exsolution flames) contains less Pd than early-forming pentlandite (cores of coarse-granular).

  16. Group V secreted phospholipase A2 is upregulated by IL-4 in human macrophages and mediates phagocytosis via hydrolysis of ethanolamine phospholipids.

    PubMed

    Rubio, Julio M; Rodríguez, Juan P; Gil-de-Gómez, Luis; Guijas, Carlos; Balboa, María A; Balsinde, Jesús

    2015-04-01

    Studies on the heterogeneity and plasticity of macrophage populations led to the identification of two major polarization states: classically activated macrophages or M1, induced by IFN-? plus LPS, and alternatively activated macrophages, induced by IL-4. We studied the expression of multiple phospholipase A2 enzymes in human macrophages and the effect that polarization of the cells has on their levels. At least 11 phospholipase A2 genes were found at significant levels in human macrophages, as detected by quantitative PCR. None of these exhibited marked changes after treating the cells with IFN-? plus LPS. However, macrophage treatment with IL-4 led to strong upregulation of the secreted group V phospholipase A2 (sPLA2-V), both at the mRNA and protein levels. In parallel with increasing sPLA2-V expression levels, IL-4-treated macrophages exhibited increased phagocytosis of yeast-derived zymosan and bacteria, and we show that both events are causally related, because cells deficient in sPLA2-V exhibited decreased phagocytosis, and cells overexpressing the enzyme manifested higher rates of phagocytosis. Mass spectrometry analyses of lipid changes in the IL-4-treated macrophages suggest that ethanolamine lysophospholipid (LPE) is an sPLA2-V-derived product that may be involved in regulating phagocytosis. Cellular levels of LPE are selectively maintained by sPLA2-V. By supplementing sPLA2-V-deficient cells with LPE, phagocytosis of zymosan or bacteria was fully restored in IL-4-treated cells. Collectively, our results show that sPLA2-V is required for efficient phagocytosis by IL-4-treated human macrophages and provide evidence that sPLA2-V-derived LPE is involved in the process. PMID:25725101

  17. Platinum-group elements (PGE) and Rhenium in Marine Sediments across the Cretaceous-Tertiary Boundary: Constraints on Re-PGE Transport in the Marine Environment

    NASA Technical Reports Server (NTRS)

    Lee, Cin-Ty Aeolus; Wasserburg, Gerald J.; Kyte, Frank T.

    2003-01-01

    The nature of Re-platinum-group element (PGE; Pt, Pd, Ir, Os, Ru) transport in the marine environment was investigated by means of marine sediments at and across the Cretaceous-Tertiary boundary (KTB) at two hemipelagic sites in Europe and two pelagic sites in the North and South Pacific. A traverse across the KTB in the South Pacific pelagic clay core found elevated levels of Re, Pt, Ir, Os, and Ru, each of which is approximately symmetrically distributed over a distance of approx. 1.8 m across the KTB. The Re-PGE abundance patterns are fractionated from chondritic relative abundances: Ru, Pt, Pd, and Re contents are slightly subchondritic relative to Ir, and Os is depleted by approx. 95% relative to chondritic Ir proportions. A similar depletion in Os (approx. 90%) was found in a sample of the pelagic KTB in the North Pacific, but it is enriched in Ru, Pt, Pd, and Re relative to Ir. The two hemipelagic KTB clays have near-chondritic abundance patterns. The approx. 1.8-m-wide Re-PGE peak in the pelagic South Pacific section cannot be reconciled with the fallout of a single impactor, indicating that postdepositional redistribution has occurred. The elemental profiles appear to fit diffusion profiles, although bioturbation could have also played a role. If diffusion had occurred over approx. 65 Ma, the effective diffusivities are approx. 10(exp -13)sq cm/s, much smaller than that of soluble cations in pore waters (approx. 10(exp -5) sq cm/s). The coupling of Re and the PGEs during redistribution indicates that postdepositional processes did not significantly fractionate their relative abundances. If redistribution was caused by diffusion, then the effective diffusivities are the same. Fractionation of Os from Ir during the KTB interval must therefore have occurred during aqueous transport in the marine environment. Distinctly subchondritic Os/Ir ratios throughout the Cenozoic in the South Pacific core further suggest that fractionation of Os from Ir in the marine environment is a general process throughout geologic time because most of the inputs of Os and Ir into the ocean have OsAr ratios greater than or = 1. Mass balance calculations show that Os and Re burial fluxes in pelagic sediments account for only a small fraction of the riverine Os (less than 10%) and Re (less than 0.1%) inputs into the oceans. In contrast, burial of Ir in pelagic sediments is similar to the riverine Ir input, indicating that pelagic sediments are a much larger repository for Ir than for Os and Re. If all of the missing Os and Re is assumed to reside in anoxic sediments in oceanic margins, the calculated burial fluxes in anoxic sediments are similar to observed burial fluxes. However, putting all of the missing Os and Re into estuarine sediments would require high concentrations to balance the riverine input and would also fail to explain the depletion of Os at pelagic KTB sites, where at most approx. 25% of the K-T impactor's Os could have passed through estuaries. If Os is preferentially sequestered in anoxic marine environments, it follows that the OsAr ratio of pelagic sediments should be sensitive to changes in the rates of anoxic sediment deposition. There is thus a clear fractionation of Os and Re from Ir in precipitation out of sea water in pelagic sections. Accordingly, it is inferred here that Re and Os are removed from sea water in anoxic marine depositional regimes.

  18. Platinum-group elements (PGE) and rhenium in marine sediments across the Cretaceous-Tertiary boundary: constraints on Re-PGE transport in the marine environment

    NASA Astrophysics Data System (ADS)

    Lee, Cin-Ty Aeolus; Wasserburg, Gerald J.; Kyte, Frank T.

    The nature of Re-platinum-group element (PGE; Pt, Pd, Ir, Os, Ru) transport in the marine environment was investigated by means of marine sediments at and across the Cretaceous-Tertiary boundary (KTB) at two hemipelagic sites in Europe and two pelagic sites in the North and South Pacific. A traverse across the KTB in the South Pacific pelagic clay core found elevated levels of Re, Pt, Ir, Os, and Ru, each of which is approximately symmetrically distributed over a distance of ˜1.8 m across the KTB. The Re-PGE abundance patterns are fractionated from chondritic relative abundances: Ru, Pt, Pd, and Re contents are slightly subchondritic relative to Ir, and Os is depleted by ˜95% relative to chondritic Ir proportions. A similar depletion in Os (˜90%) was found in a sample of the pelagic KTB in the North Pacific, but it is enriched in Ru, Pt, Pd, and Re relative to Ir. The two hemipelagic KTB clays have near-chondritic abundance patterns. The ˜1.8-m-wide Re-PGE peak in the pelagic South Pacific section cannot be reconciled with the fallout of a single impactor, indicating that postdepositional redistribution has occurred. The elemental profiles appear to fit diffusion profiles, although bioturbation could have also played a role. If diffusion had occurred over ˜65 Ma, the effective diffusivities are ˜10 -13 cm 2/s, much smaller than that of soluble cations in pore waters (˜10 -6 cm 2/s). The coupling of Re and the PGEs during redistribution indicates that postdepositional processes did not significantly fractionate their relative abundances. If redistribution was caused by diffusion, then the effective diffusivities are the same. Fractionation of Os from Ir during the KTB interval must therefore have occurred during aqueous transport in the marine environment. Distinctly subchondritic Os/Ir ratios throughout the Cenozoic in the South Pacific core further suggest that fractionation of Os from Ir in the marine environment is a general process throughout geologic time because most of the inputs of Os and Ir into the ocean have Os/Ir ratios ?1. Mass balance calculations show that Os and Re burial fluxes in pelagic sediments account for only a small fraction of the riverine Os (<10%) and Re (<0.1%) inputs into the oceans. In contrast, burial of Ir in pelagic sediments is similar to the riverine Ir input, indicating that pelagic sediments are a much larger repository for Ir than for Os and Re. If all of the missing Os and Re is assumed to reside in anoxic sediments in oceanic margins, the calculated burial fluxes in anoxic sediments are similar to observed burial fluxes. However, putting all of the missing Os and Re into estuarine sediments would require high concentrations to balance the riverine input and would also fail to explain the depletion of Os at pelagic KTB sites, where at most ˜25% of the K-T impactor's Os could have passed through estuaries. If Os is preferentially sequestered in anoxic marine environments, it follows that the Os/Ir ratio of pelagic sediments should be sensitive to changes in the rates of anoxic sediment deposition. There is thus a clear fractionation of Os and Re from Ir in precipitation out of sea water in pelagic sections. Accordingly, it is inferred here that Re and Os are removed from sea water in anoxic marine depositional regimes.

  19. V&V framework

    SciTech Connect

    Hills, Richard G.; Maniaci, David Charles; Naughton, Jonathan W.

    2015-09-01

    A Verification and Validation (V&V) framework is presented for the development and execution of coordinated modeling and experimental program s to assess the predictive capability of computational models of complex systems through focused, well structured, and formal processes.The elements of the framework are based on established V&V methodology developed by various organizations including the Department of Energy, National Aeronautics and Space Administration, the American Institute of Aeronautics and Astronautics, and the American Society of Mechanical Engineers. Four main topics are addressed: 1) Program planning based on expert elicitation of the modeling physics requirements, 2) experimental design for model assessment, 3) uncertainty quantification for experimental observations and computational model simulations, and 4) assessment of the model predictive capability. The audience for this document includes program planners, modelers, experimentalist, V &V specialist, and customers of the modeling results.

  20. Design, synthesis and (1)H NMR study of C3v-symmetric anion receptors with urethane-NH as recognition group.

    PubMed

    Park, Jin-Oh; Sahoo, Suban K; Choi, Heung-Jin

    2016-01-15

    C3v-Symmetric anion receptors 3 and 4 with urethane groups were synthesized by using trindane triol as tripodal molecular framework. In (1)H NMR titration study, the receptors showed noticeable downfield shift/disappearance of the urethane-NH peak in presence of H2PO4(-) and F(-) due to the host-guest complexation occurred through multiple hydrogen bonding and/or the deprotonation of urethane-NH groups. Other tested anions such as Cl(-), Br(-), HSO4(-), and NO3(-) showed either no or negligible chemical shift of the urethane groups. The deprotonation event in 4 allowed selective detection of F(-) by perceptible color change from colorless to yellowish-red with the appearance of a new charge transfer absorption band at 450nm. PMID:26312736

  1. Design, synthesis and 1H NMR study of C3v-symmetric anion receptors with urethane-NH as recognition group

    NASA Astrophysics Data System (ADS)

    Park, Jin-Oh; Sahoo, Suban K.; Choi, Heung-Jin

    2016-01-01

    C3v-Symmetric anion receptors 3 and 4 with urethane groups were synthesized by using trindane triol as tripodal molecular framework. In 1H NMR titration study, the receptors showed noticeable downfield shift/disappearance of the urethane-NH peak in presence of H2PO4- and F- due to the host-guest complexation occurred through multiple hydrogen bonding and/or the deprotonation of urethane-NH groups. Other tested anions such as Cl-, Br-, HSO4-, and NO3- showed either no or negligible chemical shift of the urethane groups. The deprotonation event in 4 allowed selective detection of F- by perceptible color change from colorless to yellowish-red with the appearance of a new charge transfer absorption band at 450 nm.

  2. [Memorandum 'Development of health services research in Bavaria from the perspective of the Bavarian State Working Group 'Health Services Research (LAGeV)': status quo - potential - strategies'].

    PubMed

    Hollederer, A; Braun, G E; Dahlhoff, G; Drexler, H; Engel, J; Gräßel, E; Häusler, E; Heide, H; Heuschmann, P U; Hörl, G; Imhof, H; Kaplan, M; Kasperbauer, R; Klemperer, D; Kolominsky-Rabas, P; Kuhn, J; Lang, M; Langejürgen, R; Lankes, A; Leidl, R; Liebl, B; Loss, J; Ludewig, K; Mansmann, U; Melcop, N; Nagels, K; Nowak, D; Pfundner, H; Reuschenbach, B; Schneider, A; Schneider, W; Schöffski, O; Schreiber, W; Voigtländer, S; Wildner, M; Zapf, A; Zellner, A

    2015-03-01

    The aim of the memorandum on the development of health services research (HSR) in Bavaria is to operationalise the global objectives of the State Working Group "Health Services Research" (LAGeV) and to collectively define future topics, specific implementation steps, methods as well as ways of working for the future course of the LAGeV. The LAGeV is an expert committee that integrates and links the competencies of different actors from science, politics and health care regarding HSR and facilitates their cooperation. The memorandum is based on an explorative survey among the LAGeV members, which identified the status quo of health services research in Bavaria, potential for development, important constraints, promoting factors, specific recommendations as well as future topics for the further development of HSR in Bavaria. From the perspective of the LAGeV members, the 12 most important future topics are: 1) Interface and networking research, 2) Innovative health care concepts, 3) Health care for multimorbid patients, 4)Health care for chronically ill patients, 5) Evaluation of innovations, processes and technologies, 6) Patient orientation and user focus, 7) Social and regional inequalities in health care, 8) Health care for mentally ill patients, 9) Indicators of health care quality, 10) Regional needs planning, 11) Practical effectiveness of HSR and 12) Scientific use of routine data. Potential for development of HSR in Bavaria lies a) in the promotion of networking and sustainable structures, b) the establishment of an HSR information platform that bundles information and results in regard to current topics and aims to facilitate cooperation as well as c) in the initiation of measures and projects. The latter ought to pinpoint health care challenges and make recommendations regarding the improvement of health care and its quality. The cooperation and networking structures that were established with the LAGeV should be continuously expanded and be used to work on priority topics in order to achieve the global objectives of the LAGeV. PMID:25422951

  3. 77 FR 24518 - United States v. Apple, Inc., Hachette Book Group, Inc., HarperCollins Publishers L.L.C...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-24

    ...United States v. Microsoft Corp., 56 F.3d 1448, 1461 (D.C. Cir. 1995). Under...harm third parties. See Microsoft, 56 F.3d at 1458-62. With respect to the adequacy...See generally Microsoft, 56 F.3d at 1461 (discussing whether ``the...

  4. Prevalence of Group B Streptococcus serotypes III and V in pregnant women of Rio de Janeiro, Brazil

    PubMed Central

    Soares, Georgia Cristina Tavolaro; Alviano, Daniela Sales; da Silva Santos, Gabriela; Alviano, Celuta Sales; Mattos-Guaraldi, Ana Luiza; Nagao, Prescilla Emy

    2013-01-01

    GBS serotypes III and V were the most prevalent in pregnant women and exhibited resistance to tetracycline, clindamycin and sulfamethoxazole/trimethoprim. Serotype III showed high sialic acid content and PFGE analysis discerned 33 heterogeneous profiles. Phenotypic and genotypic characterization could be relevant to control GBS infections unaffected by intra-partum chemoprophylaxis. PMID:24516454

  5. 2.1 Definition. Let R be a commutative ring. An Abelian group (A, +) together with a ``scalar'' multiplication : R A # A by elements of R is called an R

    E-print Network

    Frisch, Sophie

    2. Modules 2.1 Definition. Let R be a commutative ring. An Abelian group (A, +) together with a ``scalar'' multiplication · : R � A # A by elements of R is called an R­ module, if the following conditions hold for all r, s # R and a, b # A: (r + s)a = ra + sa (rs)a = r(sa) r(a + b) = ra + rb

  6. 2.1 Definition. Let R be a commutative ring. An Abelian group (A; +) together with a ``scalar'' multiplication \\Delta : R \\Theta A ! A by elements of R is called an R

    E-print Network

    Frisch, Sophie

    2. Modules 2.1 Definition. Let R be a commutative ring. An Abelian group (A; +) together with a ``scalar'' multiplication \\Delta : R \\Theta A ! A by elements of R is called an R­ module, if the following conditions hold for all r; s 2 R and a; b 2 A: (r + s)a = ra + sa (rs)a = r(sa) r(a + b) = ra + rb

  7. Time Distributions of Large and Small Sunspot Groups Over Four Solar Cycles , V.B. Yurchyshyn1

    E-print Network

    Observatory, Big Bear City, CA 92314 USA 2 Kandilli Observatory and Earthquake Research Institute, Bogazici Abstract: Here we analyze solar activity by focusing on time variations of the number of sunspot groups activity and its geophysical implications. Our findings may also influence our understanding of long term

  8. LBRIG Newsletter: The Trimestrial Publication of the Language by Radio Interest Group, Vol. V, No.1, September, 1976.

    ERIC Educational Resources Information Center

    Garfinkel, Alan, Ed.; And Others

    This issue of the Language by Radio Interest Group newsletter contains: an article by Paul A. Gaeng on his experience as a radio listener, an article by Richard E. Wood on "Radio Peking," and a partial reprint of frequency listings from the January 1976 number. Gaeng reports that, when he was a student in Geneva, he developed skills as a…

  9. Mechanism of catalytic aziridination with manganese corrole: the often postulated high-valent Mn(V) imido is not the group transfer reagent.

    PubMed

    Zdilla, Michael J; Abu-Omar, Mahdi M

    2006-12-27

    The reaction of Arl=NTs (Ar = 2-(tert-butylsulfonyl)benzene and Ts = p-toluenesulfonyl) and (tpfc)Mn (tpfc=5,10,15-tris(pentafluorophenyl)corrole), 1, affords the high-valent (tpfc)MnV=NTs, 2, on stopped-flow time scale. The reaction proceeds via the adduct [(tpfc)MnIII(ArINTs)], 3, with formation constant K3 = (10 +/- 2) x 10(3) L mol-1. Subsequently, 3 undergoes unimolecular group transfer to give complex 2 with the rate constant k4 = 0.26 +/- 0.07 s-1 at 24.0 degrees C. The complex (tpfc)Mn catalyzes [NTs] group transfer from ArINTs to styrene substrates with low catalyst loading and without requirement of excess olefin. The catalytic aziridination reaction is most efficient in benzene because solvents such as toluene undergo a competing hydrogen atom transfer (HAT) reaction resulting in H2NTs and lowered aziridine yields. The high-valent manganese imido complex (tpfc)Mn=NTs does not transfer its [NTs] group to styrene. Double-labeling experiments with ArINTs and ArINTstBu (TstBu = (p-tert-butylphenyl)sulfonyl) establish the source of [NR] transfer as a "third oxidant", which is an adduct of Mn(V) imido, [(tpfc)Mn(NTstBu)(ArINTs)](4). Formation of this oxidant is rate limiting in catalysis. PMID:17177448

  10. Elemental Abundance Analyses with DAO Spectrograms. XXXVIII. The SB2 Stars HR 104 (A2 V) and ? Aql (B9.5 III)

    NASA Astrophysics Data System (ADS)

    Adelman, Saul J.; Yüce, Kutluay; Gulliver, Austin F.

    2015-06-01

    The study of the elemental abundances of double-lined spectroscopic binaries should provide information on the chemical differentiation of a once uniform prestellar nebula. To determine the effective temperatures and surface gravities of the primary and secondary stellar components of HR 104 and ? Aql, we used parameters derived from their orbital analyses and the requirement of equal abundances derived from Fe I and Fe II lines. For constraints we had optical region spectrophotometry for ? Aql and the large equivalent width ratios for the many spectral metal lines which were produced in both stellar atmospheres for HR 104. Since the primary stars were much brighter than the secondary stars, the abundances are considerably better determined for the primary stars. For HR 104 A we found Teff = 9875 K, log g = 4.26, and ? = 1.7 km s-1; for HR 104 B Teff = 7200 K, log g = 4.26, and ? = 0.6 km s-1; for ? Aql A Teff = 10400 K, log = 3.63, and ? = 0.3 km s-1; and for ? Aql B Teff = 10250 K, log = 4.20, and ? = 1.9 km s-1. The abundances of HR 104 A, HR 104 B, and ? Aql A are best described as the solar pattern. Those of ? Aql B suggest a weak nonmagnetic CP star pattern. While there is no trace of the Hg II 3984 line for ? Aql, the most extreme observed abundance anomalies for the secondary are those of Ca, V, Mn, and Ni. Further study of this hot marginal Am star could provide insights into the origin of the nonsolar chemical abundances.

  11. Whitehead Groups of Spinor Groups

    NASA Astrophysics Data System (ADS)

    Monastyrny?, A. P.; Yanchevski?, V. I.

    1991-02-01

    The Whitehead groups of spinor groups are studied. The known Kneser-Tits conjecture for spinor groups is reduced to a spinor analogue of the Tannaka-Artin problem, namely, to the question of whether the group K1Spin(D), where D is a division ring of exponent 2 , is trivial. A counterexample to the Kneser-Tits problem is constructed in the class of spinor groups. The group K1Spin(D) is computed. The stability of the Whitehead groups of spinor groups under purely transcendental extensions of the ground field is established. The R-equivalence on the k-points of spinor groups and the weak approximation problem are considered. The study of spinor group completes the study of the Whitehead groups of algebraic groups of classical type, that was started in studying reduced K-theory (V.P. Platonov) and was continued for reduced unitary K-theory (V.I. Yanchevski?) and Hermitian K-theory (Platonov and Yanchevski?). Bibliography: 50 titles.

  12. Petroleum formation during serpentinization: the evidence of trace elements

    NASA Astrophysics Data System (ADS)

    Szatmari, P.; Fonseca, T. C.; Miekeley, N. F.

    2002-05-01

    An organic source of petroleum formation is well attested by many biomarkers. This need not, however, exclude contribution from inorganic sources. During serpentinization, in the absence of free oxygen, oxidation of bivalent Fe to magnetite breaks up the water molecule, generating hydrogen and creating one of the most reducing environments near the Earth's surface (Janecky & Seyfried, 1986). Szatmari (1989) proposed that some petroleum forms at plate boundaries by Fischer-Tropsch-type synthesis over serpentinizing peridotites and suggested that Ni, an element rare in the continental crust but important in both petroleum and the mantle, may be indicative of such a source. Recently, Holm and Charlou (2001) observed hydrocarbon formation by Fischer-Tropsch-type synthesis over serpentinizing peridotites of the Mid-Atlantic Ridge. To test whether the relative amounts of other trace elements in petroleum are in agreement with a serpentinizing source, we analyzed by internally coupled plasma-mass spectroscopy (ICP-MS) 22 trace elements in 68 oils sampled in seven sedimentary basins throughout Brazil. We found that trace elements in the oils correlate well with mantle peridotites and reflects the process of hydrothermal serpentinization during continental breakup. Four groups may be distinguished. In serpentinites, trace elements of the first group, Ti, Cr, Mn, and Fe, are largely retained in low-solubility magnetite and other spinels formed during serpentinization or inherited from the original peridotites. In the oils, when normalized to mantle peridotites, these elements are at relatively low levels, about 10,000 times less than their abundances in mantle peridotites, reflecting their low availability from stable minerals. In contrast, trace elements of the second group, which includes V, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Ba, La, Ce, and Nd, pass during serpentinization mostly into serpentine minerals or solution. In the oils, when normalized to mantle peridotites, these elements are at higher levels than those of the first group, about 300 times less than their abundances in mantle peridotites, reflecting their higher availability during serpentinization. Within both groups, trace metal ratios and A/(A+B) type proportionalities in the oils are close to mantle peridotites. V behaves somewhat differently: in lacustrine sequences V contents in the oils are low and the ratios of V to other elements of the second group are mantle-like, whereas in marine sequences V and its ratios to other trace elements rise by orders of magnitude. Trace elements commonly enriched in formation fluids and hydrothermal brines (Rb, Sr, Ba, Cu, Zn), when normalized to mantle peridotites, are enriched in the oils by about 0.5 order of magnitude relative to other elements of the second group. The third group of elements includes S, Mo, and As. These elements occur in the oils at abundances similar to sea water and are, when normalized to mantle peridotites and Ni, enriched in the oils by several orders of magnitude, indicating sea water reacting with peridotites during sepentinization as their possible source. Finally trace elements of the fourth group, such as Pb and Ag, are enriched in the oils by several orders of magnitude relative to both mantle peridotites and sea water and were presumably mobilized from shales by hydrothermal fluids. References:Holm, N.G. and Charlou, J.L., 2001, EPSL 191, 1-8. Janecky, D.R. and Seyfried, W.E., 1986, Geochim. Cosmochim. Acta 50, 1357-1378. Szatmari, P., 1989, AAPG Bull. 73, 989-998.

  13. Cosmic-ray energy spectra between 10 and several hundred GeV per atomic mass unit for elements from Ar-18 to Ni-28 - Results from HEAO 3

    NASA Technical Reports Server (NTRS)

    Binns, W. R.; Israel, M. H.; Jones, Michael D.; Kamionkowski, M. P.; Garrard, T. L.

    1988-01-01

    Results from the Heavy Nuclei experiment on HEAO 3 are used to determine the primary abundances of Ni and Fe. Ni and Fe are found to have nearly constant relative abundances over the interval of 10 to about 500 GeV per amu. Individual secondary elements derived principally from interactions of primary Fe nuclei are shown to display a power-law decrease in relative abundance up to about 150 GeV per amu. Ar/Fe and Ca/Fe ratios of 2.6 + or - 0.7 percent and 8.8 + or - 0.7 percent, respectively, are found, confirming a fractionation of source abundances in which elements with high values of the first ionization potential are depleted relative to those with low first ionization potential.

  14. CNO abundances in H II regions of the Magellanic clouds and the galaxy with implications regarding the nucleosynthesis of the CNO element group

    NASA Technical Reports Server (NTRS)

    Dufour, R. J.; Shields, G. A.

    1982-01-01

    Final abundance results of IUE observations of the UV spectra of three H II regions in the Small Magellanic Cloud and four H II regions in the Large Magellanic Cloud are presented. Calculated yields of carbon and oxygen derived are y(C)=.00063 and y(O)=.0016. The nucleosynthetic origin of nitrogen was evaluated as being predominantly a secondary element produced from carbon as its seed. Plotting log N/C versus log C/H yielded the rather unexpected result that log N/C decreases with lo C/H over the SMC-LMC-Orion range. The cause of this relationship is discussed.

  15. Implication of TLR- but not of NOD2-signaling pathways in dendritic cell activation by group B Streptococcus serotypes III and V.

    PubMed

    Lemire, Paul; Roy, David; Fittipaldi, Nahuel; Okura, Masatoshi; Takamatsu, Daisuke; Bergman, Eugenia; Segura, Mariela

    2014-01-01

    Group B Streptococcus (GBS) is an important agent of life-threatening invasive infection. It has been previously shown that encapsulated type III GBS is easily internalized by dendritic cells (DCs), and that this internalization had an impact on cytokine production. The receptors underlying these processes are poorly characterized. Knowledge on the mechanisms used by type V GBS to activate DCs is minimal. In this work, we investigated the role of Toll-like receptor (TLR)/MyD88 signaling pathway, the particular involvement of TLR2, and that of the intracellular sensing receptor NOD2 in the activation of DCs by types III and V GBS. The role of capsular polysaccharide (CPS, one of the most important GBS virulence factors) in bacterial-DC interactions was evaluated using non-encapsulated mutants. Despite differences in the role of CPS between types III and V GBS in bacterial internalization and intracellular survival, no major differences were observed in their capacity to modulate release of cytokines by DC. For both serotypes, CPS had a minor role in this response. Production of cytokines by DCs was shown to strongly rely on MyD88-dependent signaling pathways, suggesting that DCs recognize GBS and become activated mostly through TLR signaling. Yet, GBS-infected TLR2-/- DCs only showed a partial reduction in the production of IL-6 and CXCL1 compared to control DCs. Surprisingly, CXCL10 release by type III or type V GBS-infected DCs was MyD88-independent. No differences in DC activation were observed between NOD2-/- and control DCs. These results demonstrate the involvement of various receptors and the complexity of the cytokine production pathways activated by GBS upon DC infection. PMID:25436906

  16. Implication of TLR- but Not of NOD2-Signaling Pathways in Dendritic Cell Activation by Group B Streptococcus Serotypes III and V

    PubMed Central

    Lemire, Paul; Roy, David; Fittipaldi, Nahuel; Okura, Masatoshi; Takamatsu, Daisuke; Bergman, Eugenia; Segura, Mariela

    2014-01-01

    Group B Streptococcus (GBS) is an important agent of life-threatening invasive infection. It has been previously shown that encapsulated type III GBS is easily internalized by dendritic cells (DCs), and that this internalization had an impact on cytokine production. The receptors underlying these processes are poorly characterized. Knowledge on the mechanisms used by type V GBS to activate DCs is minimal. In this work, we investigated the role of Toll-like receptor (TLR)/MyD88 signaling pathway, the particular involvement of TLR2, and that of the intracellular sensing receptor NOD2 in the activation of DCs by types III and V GBS. The role of capsular polysaccharide (CPS, one of the most important GBS virulence factors) in bacterial-DC interactions was evaluated using non-encapsulated mutants. Despite differences in the role of CPS between types III and V GBS in bacterial internalization and intracellular survival, no major differences were observed in their capacity to modulate release of cytokines by DC. For both serotypes, CPS had a minor role in this response. Production of cytokines by DCs was shown to strongly rely on MyD88-dependent signaling pathways, suggesting that DCs recognize GBS and become activated mostly through TLR signaling. Yet, GBS-infected TLR2-/- DCs only showed a partial reduction in the production of IL-6 and CXCL1 compared to control DCs. Surprisingly, CXCL10 release by type III or type V GBS-infected DCs was MyD88-independent. No differences in DC activation were observed between NOD2-/- and control DCs. These results demonstrate the involvement of various receptors and the complexity of the cytokine production pathways activated by GBS upon DC infection. PMID:25436906

  17. Nested Sparse Approximation: Structured Estimation of V2V Channels Using Geometry-Based Stochastic Channel Model

    NASA Astrophysics Data System (ADS)

    Beygi, Sajjad; Mitra, Urbashi; Strom, Erik G.

    2015-09-01

    Future intelligent transportation systems promise increased safety and energy efficiency. Realization of such systems will require vehicle-to-vehicle (V2V) communication technology. High fidelity V2V communication is, in turn, dependent on accurate V2V channel estimation. V2V channels have characteristics differing from classical cellular communication channels. Herein, geometry-based stochastic modeling is employed to develop a characterization of V2V channel channels. The resultant model exhibits significant structure; specifically, the V2V channel is characterized by three distinct regions within the delay-Doppler plane. Each region has a unique combination of specular reflections and diffuse components resulting in a particular element-wise and group-wise sparsity. This joint sparsity structure is exploited to develop a novel channel estimation algorithm. A general machinery is provided to solve the jointly element/group sparse channel (signal) estimation problem using proximity operators of a broad class of regularizers. The alternating direction method of multipliers using the proximity operator is adapted to optimize the mixed objective function. Key properties of the proposed objective functions are proven which ensure that the optimal solution is found by the new algorithm. The effects of pulse shape leakage are explicitly characterized and compensated, resulting in measurably improved performance. Numerical simulation and real V2V channel measurement data are used to evaluate the performance of the proposed method. Results show that the new method can achieve significant gains over previously proposed methods.

  18. Specific roles for Group V secretory PLA? in retinal iron-induced oxidative stress. Implications for age-related macular degeneration.

    PubMed

    Rodríguez Diez, G; Sánchez Campos, S; Giusto, N M; Salvador, G A

    2013-08-01

    Iron accumulation and oxidative stress are hallmarks of retinas from patients with age-related macular degeneration (AMD). We have previously demonstrated that iron-overloaded retinas are a good in vitro model for the study of retinal degeneration during iron-induced oxidative stress. In this model we have previously characterized the role of cytosolic phospholipase A2 (cPLA2) and calcium-independent isoform (iPLA2). The aim of the present study was to analyze the implications of Group V secretory PLA2 (sPLA2), another member of PLA2 family, in cyclooxygenase (COX)-2 and nuclear factor kappa B (NF-?B) regulation. We found that sPLA2 is localized in cytosolic fraction in an iron concentration-dependent manner. By immunoprecipitation (IP) assays we also demonstrated an increased association between Group V sPLA2 and COX-2 in retinas exposed to iron overload. However, COX-2 activity in IP assays was observed to decrease in spite of the increased protein levels observed. p65 (RelA) NF-?B levels were increased in nuclear fractions from retinas exposed to iron. In the presence of ATK (cPLA2 inhibitor) and YM 26734 (sPLA2 inhibitor), the nuclear localization of both p65 and p50 NF-?B subunits was restored to control levels in retinas exposed to iron-induced oxidative stress. Membrane repair mechanisms were also analyzed by studying the participation of acyltransferases in phospholipid remodeling during retinal oxidation stress. Acidic phospholipids, such as phosphatidylinositol (PI) and phosphatidylserine (PS), were observed to show an inhibited acylation profile in retinas exposed to iron while phosphatidylethanolamine (PE) showed the opposite. The use of PLA2 inhibitors demonstrated that PS is actively deacylated during iron-induced oxidative stress. Results from the present study suggest that Group V sPLA2 has multiple intracellular targets during iron-induced retinal degeneration and that the specific role of sPLA2 could be related to inflammatory responses by its participation in NF-?B and COX-2 regulation. PMID:23791636

  19. 47 CFR 13.203 - Examination elements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... texts in the international Morse code at not less than the prescribed speed, using all the letters of...) Telegraphy Element 1: 16 code groups per minute. (2) Telegraphy Element 2: 20 words per minute. (3) Telegraphy Element 3: 20 code groups per minute. (4) Telegraphy Element 4: 25 words per minute....

  20. 47 CFR 13.203 - Examination elements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... texts in the international Morse code at not less than the prescribed speed, using all the letters of...) Telegraphy Element 1: 16 code groups per minute. (2) Telegraphy Element 2: 20 words per minute. (3) Telegraphy Element 3: 20 code groups per minute. (4) Telegraphy Element 4: 25 words per minute....

  1. 47 CFR 13.203 - Examination elements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... texts in the international Morse code at not less than the prescribed speed, using all the letters of...) Telegraphy Element 1: 16 code groups per minute. (2) Telegraphy Element 2: 20 words per minute. (3) Telegraphy Element 3: 20 code groups per minute. (4) Telegraphy Element 4: 25 words per minute....

  2. Anions relative location in the group-V sublattice of GaAsSbN/GaAs epilayers: XAFS measurements and simulations

    SciTech Connect

    Ciatto, G.; Harmand, J.-C.; Glas, F.; Largeau, L.; Le Du, M.; Boscherini, F.; Malvestuto, M.; Glatzel, P.; Mori, R. Alonso

    2007-06-15

    We investigated the local structure around N and Sb atoms in GaAsSbN/GaAs epilayers as a function of growth conditions and annealing time via soft and hard x-ray absorption spectroscopies in order to find out if short range ordering (SRO) in the group-V sublattice is present. SRO is one of the potential origins of the huge blueshift of the band gap observed upon annealing in these materials. By combining a Sb K- and L- and N K-edge x-ray absorption fine structure spectroscopy analysis, we demonstrate that neither strong Sb clustering nor preferential Sb-N association is possible, and that Sb atoms see a random number of N next nearest neighbors except for growth temperatures smaller than 400 deg. C, for which Sb-N neighbors in the type-V sublattice are in excess with respect to statistical disorder. On the other hand, the evolution of SRO around N anions (breaking of nitrogen pairs and randomization) can play a role in the annealing-induced band gap blueshift. Varying growth conditions and concentration modifies the band gap but, surprisingly, it does not affect the position of the conduction band minimum when Sb is incorporated.

  3. The use of artificial neural network for modelling of phycoremediation of toxic elements As(III) and As(V) from wastewater using Botryococcus braunii.

    PubMed

    Podder, M S; Majumder, C B

    2016-02-15

    In the present study, a thorough investigation has been done on the removal efficiency of both As(III) and As (V) from synthetic wastewater by phycoremediation of Botryococcus braunii algal biomass. Artificial neural networks (ANNs) are practised for predicting % phycoremediation efficiency of both As(III) and As(V) ions. The influence of several parameters for example initial pH, inoculum size, contact time and initial arsenic concentration (either As(III) or As(V)) was examined systematically. The maximum phycoremediation of As(III) and As(V) was found to be 85.22% and 88.15% at pH9.0, equilibrium time of 144h by using algal inoculum size of 10% (v/v) and initial arsenic concentration of 50mg/L. The data acquired from laboratory scale experimental set up was utilized for training a three-layer feed-forward back propagation (BP) with Levenberg-Marquardt (LM) training algorithm having 4:5:1 architecture. A comparison between the experimental data and model outputs provided a high correlation coefficient (R(2)all_ANN equal to 0.9998) and exhibited that the model was capable for predicting the phycoremediation of both As(III) and As(V) from wastewater. The network topology was optimized by changing number of neurons in hidden layers. ANNs are efficient to model and simulate highly non-liner multivariable relationships. Absolute error and Standard deviation (SD) with respect to experimental output were calculated for ANN model outputs. The comparison of phycoremediation efficiencies of both As(III) and As(V) between experimental results and ANN model outputs exhibited that ANN model can determine the behaviour of As(III) and As(V) elimination process under various circumstances. PMID:26615452

  4. TRACE ELEMENTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Trace elements are defined as mineral elements that occur in living systems in micrograms per gram of body weight or less. Trace elements of greatest practical concern in human health are iodine, iron and zinc. Suggestive evidence is emerging that cobalt (as vitamin B12), copper, selenium, boron and...

  5. NASA Constellation Program (CxP) Key Driving Requirements and Element Descriptions for International Architecture Working Group (IAWG) Functional Teams Human Transportation Cargo Transportation

    NASA Technical Reports Server (NTRS)

    Martinez, Roland M.

    2009-01-01

    The NASA Constellation uncrewed cargo mission delivers cargo to any designated location on the lunar surface (or other staging point) in a single mission. This capability is used to deliver surface infrastructure needed for lunar outpost construction, to provide periodic logistics resupply to support a continuous human lunar presence, and potentially deliver other assets to various locations.In the nominal mission mode, the Altair lunar lander is launched on Ares V into Low Earth Orbit (LEO), following a short Low Earth Orbit (LEO) loiter period, the Earth Departure Stage (EDS) performs the Trans Lunar Injection (TLI) burn and is then jettisoned. The Altair performs translunar trajectory correction maneuvers as necessary and performs the Lunar Orbit Insertion (LOI) burn. Altair then descends to the surface to land near a designated target, presumably in proximity to an Outpost location or another site of interest for exploration.Alternatively, the EDS and Altair Descent Stage could deliver assets to various staging points within their propulsive capabilities.

  6. Ring-laser gyroscope system using dispersive element(s)

    NASA Technical Reports Server (NTRS)

    Smith, David D. (Inventor)

    2010-01-01

    A ring-laser gyroscope system includes a ring-laser gyroscope (RLG) and at least one dispersive element optically coupled to the RLG's ring-shaped optical path. Each dispersive element has a resonant frequency that is approximately equal to the RLG's lasing frequency. A group index of refraction defined collectively by the dispersive element(s) has (i) a real portion that is greater than zero and less than one, and (ii) an imaginary portion that is less than zero.

  7. How Deep and Hot was Earth's Magma Ocean? Combined Experimental Datasets for the Metal-silicate Partitioning of 11 Siderophile Elements - Ni, Co, Mo, W, P, Mn, V, Cr, Ga, Cu and Pd

    NASA Technical Reports Server (NTRS)

    Righter, Kevin

    2008-01-01

    Since approximately 1990 high pressure and temperature (PT) experiments on metal-silicate systems have showed that partition coefficients (D) for siderophile (iron-loving) elements are much different than those measured at low PT conditions. The high PT data have been used to argue for a magma ocean during growth of the early Earth. Initial conclusions were based on experiments and calculations for a small number of elements such as Ni and Co. However, for many elements only a limited number of experimental data were available then, and they only hinted at values of metal-silicate D's at high PT conditions. In the ensuing decades there have been hundreds of new experiments carried out and published on a wide range of siderophile elements. At the same time several different models have been advanced to explain the siderophile elements in the earth's mantle: a) intermediate depth magma ocean; 25-30 GPa, b) deep magma ocean; up to 50 GPa, and c) early reduced and later oxidized magma ocean. Some studies have drawn conclusions based on a small subset of siderophile elements, or a set of elements that provides little leverage on the big picture (like slightly siderophile elements), and no single study has attempted to quantitatively explain more than 5 elements at a time. The purpose of this abstract is to update the predictive expressions outlined by Righter et al. (1997) with new experimental data from the last decade, test the predictive ability of these expressions against independent datasets (there are more data now to do this properly), and to apply the resulting expressions to the siderophile element patterns in Earth's upper mantle. The predictive expressions have the form: lnD = alnfO2 + b/T + cP/T + d(1Xs) + e(1Xc) + SigmafiXi + g These expressions are guided by the thermodynamics of simple metal-oxide equilibria that control each element, include terms that mimic the activity coefficients of each element in the metal and silicate, and quantify the effect of variable oxygen fugacity. Preliminary results confirm that D(Ni) and D(Co) converge at pressures near 25-30 GPa and approximately 2200 K, and show that D(Pd) and D(Cu) become too low at the PT conditions of the deepest models. Furthermore, models which force fit V and Cr mantle concentrations by metal-silicate equilibrium overlook the fact that at early Earth mantle fO2, these elements will be more compatible in Mg-perovskite and (Fe,Mg)O than in metal. Thus an intermediate depth magma ocean, at 25-30 GPa, 2200 K, and at IW-2, can explain more mantle siderophile element concentrations than other models.

  8. Single element magnetic suspension actuator

    NASA Technical Reports Server (NTRS)

    Groom, Nelson J. (inventor)

    1991-01-01

    The invention, a single element magnetic suspension actuator with bidirectional force capability along a single axis, includes an electromagnet and a nonmagnetic suspended element. A permanent magnet mounted on the suspended element interacts with a magnetic field established by the electromagnet to produce bidirectional forces in response to a variable force command voltage V (sub FC) applied to the electromagnet. A sensor measures the position of the suspended element on the single axis which is a function of force command voltage V (sub FC).

  9. Accelerator measurement of the energy spectra of neutrons emitted in the interaction of 3-GeV protons with several elements

    NASA Technical Reports Server (NTRS)

    Nalesnik, W. J.; Devlin, T. J.; Merker, M.; Shen, B. S. P.

    1972-01-01

    The application of time of flight techniques for determining the shapes of the energy spectra of neutrons between 20 and 400 MeV is discussed. The neutrons are emitted at 20, 34, and 90 degrees in the bombardment of targets by 3 GeV protons. The targets used are carbon, aluminum, cobalt, and platinum with cylindrical cross section. Targets being bombarded are located in the internal circulating beam of a particle accelerator.

  10. Myb-induced chromatin remodeling at a dual enhancer/promoter element involves non-coding rna transcription and is disrupted by oncogenic mutations of v-myb.

    PubMed

    Wilczek, Carola; Chayka, Olesya; Plachetka, Annette; Klempnauer, Karl-Heinz

    2009-12-18

    The oncogene v-myb of avian myeloblastosis virus (AMV) encodes a transcription factor (v-Myb) that transforms myelomonocytic cells by deregulating the expression of specific target genes. v-myb has acquired its oncogenic potential by truncation as well as by a number of point mutations of its cellular progenitor c-myb. As a result of these changes, the target gene spectrum v-Myb differs from that of c-Myb. We recently showed that the chicken mim-1 gene, a c-Myb target gene that is not activated by v-Myb harbors a powerful cell type-specific and Myb-inducible enhancer in addition to a Myb-responsive promoter. We now show that Myb-dependent activation of the mim-1 gene is accompanied by extensive remodeling of the nucleosomal architecture at the enhancer. We found that the mim-1 enhancer region also harbors a promoter whose activity is stimulated by Myb and which directs the transcription of an apparently non-coding RNA. Furthermore, our data show that the oncogenic mutations of AMV have disrupted the ability of v-Myb to induce remodeling of chromatin structure at the mim-1 enhancer. Together, our results demonstrate for the first time directly that Myb induces alterations of the nucleosomal organization at a relevant target site and provide new insight into the functional consequences of the oncogenic amino acid substitutions. PMID:19841477

  11. Myb-induced Chromatin Remodeling at a Dual Enhancer/Promoter Element Involves Non-coding RNA Transcription and Is Disrupted by Oncogenic Mutations of v-myb*

    PubMed Central

    Wilczek, Carola; Chayka, Olesya; Plachetka, Annette; Klempnauer, Karl-Heinz

    2009-01-01

    The oncogene v-myb of avian myeloblastosis virus (AMV) encodes a transcription factor (v-Myb) that transforms myelomonocytic cells by deregulating the expression of specific target genes. v-myb has acquired its oncogenic potential by truncation as well as by a number of point mutations of its cellular progenitor c-myb. As a result of these changes, the target gene spectrum v-Myb differs from that of c-Myb. We recently showed that the chicken mim-1 gene, a c-Myb target gene that is not activated by v-Myb harbors a powerful cell type-specific and Myb-inducible enhancer in addition to a Myb-responsive promoter. We now show that Myb-dependent activation of the mim-1 gene is accompanied by extensive remodeling of the nucleosomal architecture at the enhancer. We found that the mim-1 enhancer region also harbors a promoter whose activity is stimulated by Myb and which directs the transcription of an apparently non-coding RNA. Furthermore, our data show that the oncogenic mutations of AMV have disrupted the ability of v-Myb to induce remodeling of chromatin structure at the mim-1 enhancer. Together, our results demonstrate for the first time directly that Myb induces alterations of the nucleosomal organization at a relevant target site and provide new insight into the functional consequences of the oncogenic amino acid substitutions. PMID:19841477

  12. Data Elements Search - Data Elements

    Cancer.gov

     CDE  Cart  Home   FormBuilder   Help  Admin Tool  Curation Tool  NCI Metathesaurus  NCI Terminology Server  Sentinel Tool  UML Model Browser     What's new   Available DownloadsNew!   Data Element Search Search for Data Elements Search preferences

  13. Solvent Refined Coal (SRC) process: trace elements. Volume III. Pilot plant development work. Part 6. Fate of trace elements in the SRC process. [Ph. D. Thesis

    SciTech Connect

    Weiss, C.S.

    1980-09-01

    A study of the forms of trace elements occurring in Solvent Refined Coal has been performed by chemical separation of the Solvent Refined Coal based on differences in the functionality and molecular weight of the organic matrix. Analysis of the fractions separated for various trace elements has revealed associations of certain elements with other elements as well as with certain fractions. The analysis of Solvent Refined Coal I by these methods provided data on the distribution of Ti, V, Ca, S, Al, Mn, As, Se, Cr, Fe, Ni, Zn, Sc, and Ga in the fractions generated. Because of the low trace element content of Solvent Refined Coal II only As, Se, and Cr could be detected in the silica fractions. Based on the distributions three different groups of elements have been based on the association of elements with each other and with certain fractions. The first group is composed of As, Se, and Cr associated with silica fractions of relatively low functionality; these elements have a high percent solubility in the starting Solvent Refined Coal II oil. The second group composed of Ti, V, and to a lesser extent a second form of Cr, is associated with fractions that have a high concentration of phenolic material and is probably present as phenoxide complexes. The third group composed of Fe, Ca, K, Al, and Mg is associated with the most functional fractions and is possibly present as humic acid type complexes or as submicron size particulates. The integration of chromatographic methods with trace element analysis of the fractions generated is capable of discerning the presence of different forms of the elements. The methods used are applicable to other important geologically occurring organic matter.

  14. Finite Volume Element Method

    E-print Network

    2003-12-06

    65N10, 65N30. ?This research was sponsored in part by the Air Force Office of Scientific Research under ...... [5] Cai, Z.: A theoretical foundation of the finite volume element method, Ph.D Thesis, ... Sample control volume V h (dotted lines

  15. A Measurement of the Top Quark Mass with the D0 Detector at s**(1/2) = 1.96-TeV using the Matrix Element Method

    SciTech Connect

    Kroeninger, Kevin Alexander; /Bonn U.

    2004-04-01

    Using a data set of 158 and 169 pb{sup -1} of D0 Run-II data in the electron and muon plus jets channel, respectively, the top quark mass has been measured using the Matrix Element Method. The method and its implementation are described. Its performance is studied in Monte Carlo using ensemble tests and the method is applied to the Moriond 2004 data set.

  16. Group 12 Elements and Their Small Clusters:. Electric Dipole Polarizability of Zn, cd and Hg, Zn2 Dimer and Higher Znn Microclusters and Neutral, Cationic and Anionic Zinc Oxide Molecules (ZnO, ZnO+ and ZnO-)

    NASA Astrophysics Data System (ADS)

    Oymak, Hüseyin; Erkoç, ?akir

    This review is in general about group 12 elements and their small microclusters. In this part, after presenting an extensive literature survey of the electric dipole polarizability studies of the Zn, Cd and Hg atoms, we specifically target zinc-containing small clusters, beginning with the Zn2 dimer, the Zn3 trimer, higher Znn clusters and the neutral, cationic and anionic zinc oxide clusters: ZnO, ZnO+ and ZnO-. We tabulated experimental and theoretical results for the spectroscopic constants (dissociation energy De or D0, bond length re, fundamental frequency we, anharmonicity constant wexe and dipole moment ?e) of the diatomic clusters and the first and second ionization potentials IP1 and IP2 and electron affinity EA of the species reviewed.

  17. Tevatron Combination of Single-Top-Quark Cross Sections and Determination of the Magnitude of the Cabibbo-Kobayashi-Maskawa Matrix Element V[subscript tb

    E-print Network

    Aaltonen, T.

    We present the final combination of CDF and D0 measurements of cross sections for single-top-quark production in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV. The data correspond to total integrated ...

  18. p-adic Groups Seminar / Study group

    E-print Network

    Carbone, Lisa

    , and accounts of it have been written by Tits and Satake. Tits compiled tables of `admissible indices' from which groups can be constructed. We describe Tits' tables for groups of relative rank 1 over non in pure and applied mathematics ; v. 3. [Ti1] Tits, J, Reductive groups over local fields, Automorphic

  19. Critical role of phospholipase A2 group IID in age-related susceptibility to severe acute respiratory syndrome-CoV infection.

    PubMed

    Vijay, Rahul; Hua, Xiaoyang; Meyerholz, David K; Miki, Yoshimi; Yamamoto, Kei; Gelb, Michael; Murakami, Makoto; Perlman, Stanley

    2015-10-19

    Oxidative stress and chronic low-grade inflammation in the lungs are associated with aging and may contribute to age-related immune dysfunction. To maintain lung homeostasis, chronic inflammation is countered by enhanced expression of proresolving/antiinflammatory factors. Here, we show that age-dependent increases of one such factor in the lungs, a phospholipase A2 (PLA2) group IID (PLA2G2D) with antiinflammatory properties, contributed to worse outcomes in mice infected with severe acute respiratory syndrome-coronavirus (SARS-CoV). Strikingly, infection of mice lacking PLA2G2D expression (Pla2g2d(-/-) mice) converted a uniformly lethal infection to a nonlethal one (>80% survival), subsequent to development of enhanced respiratory DC migration to the draining lymph nodes, augmented antivirus T cell responses, and diminished lung damage. We also observed similar effects in influenza A virus-infected middle-aged Pla2g2d(-/-) mice. Furthermore, oxidative stress, probably via lipid peroxidation, was found to induce PLA2G2D expression in mice and in human monocyte-derived macrophages. Thus, our results suggest that directed inhibition of a single inducible phospholipase, PLA2G2D, in the lungs of older patients with severe respiratory infections is potentially an attractive therapeutic intervention to restore immune function. PMID:26392224

  20. Large-signal characterizations of DDR IMPATT devices based on group III-V semiconductors at millimeter-wave and terahertz frequencies

    NASA Astrophysics Data System (ADS)

    Acharyya, Aritra; Mallik, Aliva; Banerjee, Debopriya; Ganguli, Suman; Das, Arindam; Dasgupta, Sudeepto; Banerjee, J. P.

    2014-08-01

    Large-signal (L-S) characterizations of double-drift region (DDR) impact avalanche transit time (IMPATT) devices based on group III-V semiconductors such as wurtzite (Wz) GaN, GaAs and InP have been carried out at both millimeter-wave (mm-wave) and terahertz (THz) frequency bands. A L-S simulation technique based on a non-sinusoidal voltage excitation (NSVE) model developed by the authors has been used to obtain the high frequency properties of the above mentioned devices. The effect of band-to-band tunneling on the L-S properties of the device at different mm-wave and THz frequencies are also investigated. Similar studies are also carried out for DDR IMPATTs based on the most popular semiconductor material, i.e. Si, for the sake of comparison. A comparative study of the devices based on conventional semiconductor materials (i.e. GaAs, InP and Si) with those based on Wz-GaN shows significantly better performance capabilities of the latter at both mm-wave and THz frequencies.

  1. Scrambled Elements Literate Software Systems

    E-print Network

    Pike, Robert D.

    Scrambled Elements 1 S 15 L 19 A 23 V 29 T 38 E 42 E 50 L 58 A 62 O 70 E 78 R 82 O 86 S 2 P A C E serve 20. Scrambled element #87 22. Response to danger 23. Remnant 25. Scrambled elelement #52 27. ____ Any Place (Janet Jackson hit) 46. Scrambled element #101 50. Folklore 53. Psych lab need 54. Org

  2. Elemental health

    SciTech Connect

    Tonneson, L.C.

    1997-01-01

    Trace elements used in nutritional supplements and vitamins are discussed in the article. Relevant studies are briefly cited regarding the health effects of selenium, chromium, germanium, silicon, zinc, magnesium, silver, manganese, ruthenium, lithium, and vanadium. The toxicity and food sources are listed for some of the elements. A brief summary is also provided of the nutritional supplements market.

  3. Tevatron combination of single-top-quark cross sections and determination of the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element $\\bf V_{tb}$

    E-print Network

    CDF Collaboration; D0 Collaboration

    2015-03-17

    We present the final combination of CDF and D0 measurements of cross sections for single-top-quark production in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV. The data correspond to total integrated luminosities of up to 9.7 fb$^{-1}$ per experiment. The $t$-channel cross section is measured to be $\\sigma_t = 2.25^{+0.29}_{-0.31}$ pb. We also present the combinations of the two-dimensional measurements of the $s$- vs. $t$-channel cross sections and of the $s+t$ channel cross section measurement resulting in $\\sigma_{s+t} = 3.30^{+0.52}_{-0.40}$ pb, without assuming the standard-model value for the ratio $\\sigma_s/\\sigma_t$. The resulting value of the magnitude of the top-to-bottom quark coupling is $|V_{tb}|$ = $1.02^{+0.06}_{-0.05}$, corresponding to $|V_{tb}| > 0.92$ at the 95% C.L.

  4. Tevatron Combination of Single-Top-Quark Cross Sections and Determination of the Magnitude of the Cabibbo-Kobayashi-Maskawa Matrix Element V_{tb}.

    PubMed

    Aaltonen, T; Abazov, V M; Abbott, B; Acharya, B S; Adams, M; Adams, T; Agnew, J P; Alexeev, G D; Alkhazov, G; Alton, A; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Arisawa, T; Artikov, A; Asaadi, J; Ashmanskas, W; Askew, A; Atkins, S; Auerbach, B; Augsten, K; Aurisano, A; Avila, C; Azfar, F; Badaud, F; Badgett, W; Bae, T; Bagby, L; Baldin, B; Bandurin, D V; Banerjee, S; Barbaro-Galtieri, A; Barberis, E; Baringer, P; Barnes, V E; Barnett, B A; Barria, P; Bartlett, J F; Bartos, P; Bassler, U; Bauce, M; Bazterra, V; Bean, A; Bedeschi, F; Begalli, M; Behari, S; Bellantoni, L; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Beri, S B; Bernardi, G; Bernhard, R; Bertram, I; Besançon, M; Beuselinck, R; Bhat, P C; Bhatia, S; Bhatnagar, V; Bhatti, A; Bland, K R; Blazey, G; Blessing, S; Bloom, K; Blumenfeld, B; Bocci, A; Bodek, A; Boehnlein, A; Boline, D; Boos, E E; Borissov, G; Bortoletto, D; Borysova, M; Boudreau, J; Boveia, A; Brandt, A; Brandt, O; Brigliadori, L; Brock, R; Bromberg, C; Bross, A; Brown, D; Brucken, E; Bu, X B; Budagov, J; Budd, H S; Buehler, M; Buescher, V; Bunichev, V; Burdin, S; Burkett, K; Busetto, G; Bussey, P; Buszello, C P; Butti, P; Buzatu, A; Calamba, A; Camacho-Pérez, E; Camarda, S; Campanelli, M; Canelli, F; Carls, B; Carlsmith, D; Carosi, R; Carrillo, S; Casal, B; Casarsa, M; Casey, B C K; Castilla-Valdez, H; Castro, A; Catastini, P; Caughron, S; Cauz, D; Cavaliere, V; Cerri, A; Cerrito, L; Chakrabarti, S; Chan, K M; Chandra, A; Chapon, E; Chen, G; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Cho, K; Cho, S W; Choi, S; Chokheli, D; Choudhary, B; Cihangir, S; Claes, D; Clark, A; Clarke, C; Clutter, J; Convery, M E; Conway, J; Cooke, M; Cooper, W E; Corbo, M; Corcoran, M; Cordelli, M; Couderc, F; Cousinou, M-C; Cox, C A; Cox, D J; Cremonesi, M; Cruz, D; Cuevas, J; Culbertson, R; Cutts, D; Das, A; d'Ascenzo, N; Datta, M; Davies, G; de Barbaro, P; de Jong, S J; De La Cruz-Burelo, E; Déliot, F; Demina, R; Demortier, L; Deninno, M; Denisov, D; Denisov, S P; D'Errico, M; Desai, S; Deterre, C; DeVaughan, K; Devoto, F; Di Canto, A; Di Ruzza, B; Diehl, H T; Diesburg, M; Ding, P F; Dittmann, J R; Dominguez, A; Donati, S; D'Onofrio, M; Dorigo, M; Driutti, A; Dubey, A; Dudko, L V; Duperrin, A; Dutt, S; Eads, M; Ebina, K; Edgar, R; Edmunds, D; Elagin, A; Ellison, J; Elvira, V D; Enari, Y; Erbacher, R; Errede, S; Esham, B; Evans, H; Evdokimov, A; Evdokimov, V N; Farrington, S; Fauré, A; Feng, L; Ferbel, T; Fernández Ramos, J P; Fiedler, F; Field, R; Filthaut, F; Fisher, W; Fisk, H E; Flanagan, G; Forrest, R; Fortner, M; Fox, H; Franklin, M; Freeman, J C; Frisch, H; Fuess, S; Funakoshi, Y; Galloni, C; Garbincius, P H; Garcia-Bellido, A; García-González, J A; Garfinkel, A F; Garosi, P; Gavrilov, V; Geng, W; Gerber, C E; Gerberich, H; Gerchtein, E; Gershtein, Y; Giagu, S; Giakoumopoulou, V; Gibson, K; Ginsburg, C M; Ginther, G; Giokaris, N; Giromini, P; Glagolev, V; Glenzinski, D; Gogota, O; Gold, M; Goldin, D; Golossanov, A; Golovanov, G; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González López, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gramellini, E; Grannis, P D; Greder, S; Greenlee, H; Grenier, G; Gris, Ph; Grivaz, J-F; Grohsjean, A; Grosso-Pilcher, C; Group, R C; Grünendahl, S; Grünewald, M W; Guillemin, T; Guimaraes da Costa, J; Gutierrez, G; Gutierrez, P; Hahn, S R; Haley, J; Han, J Y; Han, L; Happacher, F; Hara, K; Harder, K; Hare, M; Harel, A; Harr, R F; Harrington-Taber, T; Hatakeyama, K; Hauptman, J M; Hays, C; Hays, J; Head, T; Hebbeker, T; Hedin, D; Hegab, H; Heinrich, J; Heinson, A P; Heintz, U; Hensel, C; Heredia-De La Cruz, I; Herndon, M; Herner, K; Hesketh, G; Hildreth, M D; Hirosky, R; Hoang, T; Hobbs, J D; Hocker, A; Hoeneisen, B; Hogan, J; Hohlfeld, M; Holzbauer, J L; Hong, Z; Hopkins, W; Hou, S; Howley, I; Hubacek, Z; Hughes, R E; Husemann, U; Hussein, M; Huston, J; Hynek, V; Iashvili, I; Ilchenko, Y; Illingworth, R; Introzzi, G; Iori, M; Ito, A S; Ivanov, A; Jabeen, S; Jaffré, M; James, E; Jang, D; Jayasinghe, A; Jayatilaka, B; Jeon, E J; Jeong, M S; Jesik, R; Jiang, P; Jindariani, S; Johns, K; Johnson, E; Johnson, M; Jonckheere, A; Jones, M; Jonsson, P; Joo, K K; Joshi, J; Jun, S Y; Jung, A W; Junk, T R; Juste, A; Kajfasz, E; Kambeitz, M; Kamon, T; Karchin, P E; Karmanov, D; Kasmi, A; Kato, Y; Katsanos, I; Kaur, M; Kehoe, R; Kermiche, S; Ketchum, W; Keung, J; Khalatyan, N; Khanov, A; Kharchilava, A; Kharzheev, Y N; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S H; Kim, S B; Kim, Y J; Kim, Y K; Kimura, N; Kirby, M; Kiselevich, I; Knoepfel, K; Kohli, J M; Kondo, K; Kong, D J; Konigsberg, J; Kotwal, A V; Kozelov, A V; Kraus, J; Kreps, M; Kroll, J; Kruse, M; Kuhr, T; Kumar, A; Kupco, A; Kurata, M; Kur?a, T; Kuzmin, V A; Laasanen, A T; Lammel, S; Lammers, S; Lancaster, M; Lannon, K; Latino, G

    2015-10-01

    We present the final combination of CDF and D0 measurements of cross sections for single-top-quark production in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV. The data correspond to total integrated luminosities of up to 9.7??fb^{-1} per experiment. The t-channel cross section is measured to be ?_{t}=2.25_{-0.31}^{+0.29}??pb. We also present the combinations of the two-dimensional measurements of the s- vs t-channel cross section. In addition, we give the combination of the s+t channel cross section measurement resulting in ?_{s+t}=3.30_{-0.40}^{+0.52}??pb, without assuming the standard model value for the ratio ?_{s}/?_{t}. The resulting value of the magnitude of the top-to-bottom quark coupling is |V_{tb}|=1.02_{-0.05}^{+0.06}, corresponding to |V_{tb}|>0.92 at the 95% C.L. PMID:26550718

  5. Discovery of the heaviest elements.

    PubMed

    Heßberger, Fritz P

    2013-02-25

    The search for new superheavy elements (SHEs) is at present one of the most exciting adventures in nuclear physics. Thanks to enhanced experimental techniques, the synthesis of elements Z=113 to 118 in reactions using (48)Ca projectiles and targets made of isotopes of the elements neptunium to californium has been claimed. Discovery of the elements Z=114 (named flerovium) and Z=116 (named livermorium) has been accepted by the IUPAC. The others are waiting. The situation for element 113 is particular; here claims on discovery come from groups from RIKEN, Wako, Saitama, Japan and FLNR-JINR, Dubna, Russia. PMID:23335329

  6. TROPODEGRADABLE HALOCARBONS AND MAIN GROUP ELEMENT COMPOUNDS

    EPA Science Inventory

    Although it is not certain that a "drop-in" chemical substitute (as opposed to a new technology) for halons that can be used in normally occupied areas will ever be identified, there are two promising paths to such an agent. The first is to target bromocarbons with very short atm...

  7. Relative abundances of elements (20 or = Z or = 28) at energies up to 70 GeV/amu using relativistic rise in ion chambers

    NASA Technical Reports Server (NTRS)

    Barthelmy, S. D.; Israel, M. H.; Klarmann, J.

    1985-01-01

    The results of a new balloon borne cosmic ray detector flown from Palestine, TX in Sept., 1982 are discussed. The exposure of 62 square meter-ster-hr is sufficient to prove the concept of using gas ionization chambers as energy measuring devices in the relativistic rise region. The abundances, relative Fe-26, of the pure secondaries Cr-22 and Ti-24, the pure primary Ni26, and the mixed primary and secondary Ca-20 between 6 and 70GeV/amu were measured.

  8. Testing WIMS-D4M cross sections and the ANL ENDF/B-V 69 group library. Results from global diffusion and Monte Carlo calculations compared with measurements in the Romanian 14-MW TRIGA reactor

    SciTech Connect

    Bretscher, M.M.

    1993-12-31

    The WIMS-D4 code has been modified (WIMS-D4M) to produce microscopic isotopic cross sections in ISOTXS format for use in diffusion and transport calculations. Beginning with 69-group libraries based on ENDF/B-V data, numerous cell calculations have been made to prepare a set of broad group cross sections for use in diffusion calculations. Global calculations have been made for two control rod states of the Romanian steady state TRIGA reactor with 29 fresh HEU fuel clusters. Detailed Monte Carlo calculations also have been performed for the same reactor configurations using data based on ENDF/B-V. Results from these global calculations are compared with each other and with the measured excess reactivities. Although region-averaged macroscopic principal cross sections obtained from WIMS-D4M are in good agreement with the corresponding Monte Carlo values, problems exist with the high energy (E > 10 keV) microscopic hydrogen transport cross sections.

  9. Chemical characterization of element 112.

    PubMed

    Eichler, R; Aksenov, N V; Belozerov, A V; Bozhikov, G A; Chepigin, V I; Dmitriev, S N; Dressler, R; Gäggeler, H W; Gorshkov, V A; Haenssler, F; Itkis, M G; Laube, A; Lebedev, V Ya; Malyshev, O N; Oganessian, Yu Ts; Petrushkin, O V; Piguet, D; Rasmussen, P; Shishkin, S V; Shutov, A V; Svirikhin, A I; Tereshatov, E E; Vostokin, G K; Wegrzecki, M; Yeremin, A V

    2007-05-01

    The heaviest elements to have been chemically characterized are seaborgium (element 106), bohrium (element 107) and hassium (element 108). All three behave according to their respective positions in groups 6, 7 and 8 of the periodic table, which arranges elements according to their outermost electrons and hence their chemical properties. However, the chemical characterization results are not trivial: relativistic effects on the electronic structure of the heaviest elements can strongly influence chemical properties. The next heavy element targeted for chemical characterization is element 112; its closed-shell electronic structure with a filled outer s orbital suggests that it may be particularly susceptible to strong deviations from the chemical property trends expected within group 12. Indeed, first experiments concluded that element 112 does not behave like its lighter homologue mercury. However, the production and identification methods used cast doubt on the validity of this result. Here we report a more reliable chemical characterization of element 112, involving the production of two atoms of (283)112 through the alpha decay of the short-lived (287)114 (which itself forms in the nuclear fusion reaction of 48Ca with 242Pu) and the adsorption of the two atoms on a gold surface. By directly comparing the adsorption characteristics of (283)112 to that of mercury and the noble gas radon, we find that element 112 is very volatile and, unlike radon, reveals a metallic interaction with the gold surface. These adsorption characteristics establish element 112 as a typical element of group 12, and its successful production unambiguously establishes the approach to the island of stability of superheavy elements through 48Ca-induced nuclear fusion reactions with actinides. PMID:17476264

  10. Elemental Education.

    ERIC Educational Resources Information Center

    Daniel, Esther Gnanamalar Sarojini; Saat, Rohaida Mohd.

    2001-01-01

    Introduces a learning module integrating three disciplines--physics, chemistry, and biology--and based on four elements: carbon, oxygen, hydrogen, and silicon. Includes atomic model and silicon-based life activities. (YDS)

  11. Measurement of the t-channel single-top-quark production cross section and of the |Vtb| CKM matrix element in pp collisions at sqrt(s) = 8 TeV

    SciTech Connect

    Khachatryan, V.; et al.,

    2014-06-01

    Measurements are presented of the t-channel single-top-quark production cross section in proton-proton collisions at ?s = 8 TeV. The results are based on a data sample corresponding to an integrated luminosity of 19.7 fb?¹ recorded with the CMS detector at the LHC. The cross section is measured inclusively, as well as separately for top (t) and antitop $ \\left(\\overline{\\mathrm{t}}\\right) $ , in final states with a muon or an electron. The measured inclusive t-channel cross section is ?t-ch. = 83.6 ± 2.3 (stat.) ± 7.4 (syst.) pb. The single t and $ \\overline{\\mathrm{t}} $ cross sections are measured to be ?t-ch.(t) = 53.8 ± 1.5 (stat.) ± 4.4 (syst.) pb and ?$_{t-ch.}$ $ \\left(\\overline{t}\\right) $ = 27.6 ± 1.3 (stat.) ± 3.7 (syst.) pb, respectively. The measured ratio of cross sections is Rt-ch. = ?t-ch.(t)/?t-ch. $ \\left(\\overline{\\mathrm{t}}\\right) $ = 1.95 ± 0.10 (stat.) ± 0.19 (syst.), in agreement with the standard model prediction. The modulus of the Cabibbo-Kobayashi-Maskawa matrix element Vtb is extracted and, in combination with a previous CMS result at ?s = 7 TeV, a value |Vtb| = 0.998 ± 0.038 (exp.) ± 0.016 (theo.) is obtained.

  12. [Removal of gaseous elemental mercury over cerium doped low vanadium loading V2O5-WO3/TiO2 in simulated coal-fired flue gas].

    PubMed

    Wan, Qi; Duan, Lei; He, Ke-Bin; Chen, Liang; Li, Jun-Hua

    2011-09-01

    This paper discussed a recent study of mercury removal by gaseous hydrogen chloride over novel Ce doped low vanadium V2O5-WO3/TiO2 catalysts under a bench scale condition. The performances on Hg(0) removal over the catalyst were tested in simulated flue gas with 80-100 microg x m(-3) Hg(0), 8% O2, 10 x10(-6) HCl, 8% H2O, 800 x10(-6) SO2 and balanced with N2. Results showed that about 95% of Hg(0) could be removed. According to the characterization results, BET surface areas had not significant influence on catalytic performance. XPS results indicated that Ce4+ oxide was a mainly form in the catalysts surface, which was beneficial for Hg(0) removal reactions. Water vapor slightly inhibited Hg(0) removal efficiency, due to the competitive adsorption, however, SO2 promoted the oxidation reactions, resulting in higher removal efficiencies. PMID:22165254

  13. 47 CFR 13.203 - Examination elements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... texts in the international Morse code at not less than the prescribed speed, using all the letters of...) Telegraphy Element 1: 16 code groups per minute. (2) Telegraphy Element 2: 20 words per minute....

  14. Actinide collisions for QED and superheavy elements with the time-dependent Hartree-Fock theory and the Balian-V\\'en\\'eroni variational principle

    E-print Network

    Simenel, Cédric; Kedziora, David J

    2011-01-01

    Collisions of actinide nuclei form, during very short times of few zs ($10^{-21}$ s), the heaviest ensembles of interacting nucleons available on Earth. Such collisions are used to produce super-strong electric fields by the huge number of interacting protons to test spontaneous positron-electron pair emission (vacuum decay) predicted by the quantum electrodynamics (QED) theory. Multi-nucleon transfer in actinide collisions could also be used as an alternative way to fusion in order to produce neutron-rich heavy and superheavy elements thanks to inverse quasifission mechanisms. Actinide collisions are studied in a dynamical quantum microscopic approach. The three-dimensional time-dependent Hartree-Fock (TDHF) code {\\textsc{tdhf3d}} is used with a full Skyrme energy density functional to investigate the time evolution of expectation values of one-body operators, such as fragment position and particle number. This code is also used to compute the dispersion of the particle numbers (e.g., widths of fragment mass...

  15. Effects of long-lived 10 MeV-scale sterile neutrinos on primordial elemental abundances and the effective neutrino number

    NASA Astrophysics Data System (ADS)

    Ishida, Hiroyuki; Kusakabe, Motohiko; Okada, Hiroshi

    2014-10-01

    The primordial lithium abundance inferred from spectroscopic observations of metal-poor stars is ˜3 times smaller than the theoretical prediction in the standard big bang nucleosynthesis (BBN) model. We assume a simple model composed of standard model particles and a sterile neutrino ?H with mass of O(10) MeV which decays long after BBN. We then investigate cosmological effects of a sterile neutrino decay, and check if a sterile neutrino can reduce the primordial lithium abundance. We formulate the injection spectrum of nonthermal photon induced by the ?H decay. We take into account the generation of electrons and positrons, e±'s, and active neutrinos at the ?H decay, the primary photon production via the inverse Compton scattering of cosmic background radiation (CBR) by energetic e±, and electromagnetic cascade showers induced by the primary photons. The steady state injection spectrum is then derived as a function of the ?H mass and the photon temperature. The ?H decay produces energetic active neutrinos which are not thermalized, and e±'s which are thermalized. We then derive formulas relevant to the ?H decay rates and formulas for the baryon-to-photon ratio ? and effective neutrino number Neff. The initial abundance, mass, and lifetime of ?H are taken as free parameters. We then consistently solve (1) the cosmic thermal history, (2) nonthermal nucleosynthesis induced by the nonthermal photons, (3) the ? value, and (4) the Neff value. We find that an effective Be7 destruction can occur only if the sterile neutrino decays at photon temperature T =O(1) keV. Amounts of energy injection at the ?H decay are constrained from limits on primordial D and Li7 abundances, the Neff value, and the CBR energy spectrum. We find that Be7 is photodisintegrated and the Li problem is partially solved for the lifetime 104-105 s and the mass ?14 MeV. Be7 destruction by more than a factor of 3 is not possible because of an associated D overdestruction. In the parameter region, the ? value is decreased slightly, while the Neff value is increased by a factor of ?Neff?1. In this study, errors in photodisintegration cross sections of Be7(? ,?)He3 and Li7(? ,?)H3 that have propagated through the literature are corrected, and new functions are derived based on recent nuclear experiments. It is found that the new photodisintegration rates are 2.3 to 2.5 times smaller than the old rates. The correct cross sections thus indicate significantly smaller efficiencies of Be7 and Li7 photodisintegration. Abundances of sterile neutrino necessary for the Li7 reduction are much smaller than thermal freeze-out abundances. The relic sterile neutrino, therefore, must be diluted between the freeze-out and BBN epochs by some mechanism.

  16. Seroprotective Antibodies to 2011 Variant Influenza A(H3N2v) and Seasonal Influenza A(H3N2) among Three Age Groups of US Department of Defense Service Members

    PubMed Central

    Radin, Jennifer M.; Hawksworth, Anthony W.; Ortiguerra, Ryan G.; Brice, Gary T.

    2015-01-01

    Background In 2011, a new variant of influenza A(H3N2) emerged that contained a recombination of genes from swine H3N2 viruses and the matrix (M) gene of influenza A(H1N1)pdm09 virus. New combinations and variants of pre-existing influenza viruses are worrisome if there is low or nonexistent immunity in a population, which increases chances for an outbreak or pandemic. Methods Sera collected in 2011 were obtained from US Department of Defense service members in three age groups: 19–21 years, 32–33 years, and 47–48 years. Pre- and post-vaccination samples were available for the youngest age group, and postvaccination samples for the two older groups. Specimens were tested using microneutralization assays for antibody titers against H3N2v (A/Indiana/10/2011) and seasonal H3N2 virus (A/Perth/16/2009). Results The youngest age group had significantly (p<0.05) higher geometric mean titers for H3N2v with 165 (95% confidence interval [CI]: 105–225) compared with the two older groups, aged 32–33 and 47–48 years, who had geometric mean titers of 68 (95% CI: 55–82) and 46 (95% CI: 24–65), respectively. Similarly, the youngest age group also had the highest geometric mean titers for seasonal H3N2. In the youngest age group, the proportion of patients who seroconverted after vaccination was 12% for H3N2v and 27% for seasonal H3N2. Discussion Our results were similar to previous studies that found highest seroprotection among young adults and decreasing titers among older adults. The proportion of 19- to 21-year-olds who seroconverted after seasonal vaccination was low and similar to previous findings. Improving our understanding of H3N2v immunity among different age groups in the United States can help inform vaccination plans if H3N2v becomes more transmissible in the future. PMID:25816244

  17. Crystal structures of two deca­vanadates(V) with penta­aqua­manganese(II) pendant groups: (NMe4)2[V10O28{Mn(H2O)5}2]·5H2O and [NH3C(CH2OH)3]2[V10O28{Mn(H2O)5}2]·2H2O

    PubMed Central

    Franco, Maurício P.; Rüdiger, André Luis; Soares, Jaísa F.; Nunes, Giovana G.; Hughes, David L.

    2015-01-01

    Two heterometallic deca­vanadate(V) compounds, bis­(tetra­methyl­ammonium) deca­aquadi-?4-oxido-tetra-?3-oxido-hexa­deca-?2-oxido-hexa­oxidodimang­anese(II)­deca­vanadate(V) penta­hydrate, (Me4N)2[V10O28{Mn(H2O)5}2]·5H2O, A, and bis­{[tris­(hy­droxy­meth­yl)meth­yl]ammonium} deca­aquadi-?4-oxido-tetra-?3-oxido-hexa­deca-?2-oxido-hexa­oxidodimanganese(II)deca­vanadate(V) dihydrate, [NH3C(CH2OH)3]2[V10O28{Mn(H2O)5}2]·2H2O, B, have been synthesized under mild reaction conditions in an aqueous medium. Both polyanions present two [Mn(OH2)5]2+ complex units bound to the deca­vanadate cluster through oxide bridges. In A, the deca­vanadate unit has 2/m symmetry, whereas in B it has twofold symmetry. Apart from this, the main differences between A and B rest on the organic cations, tetra­methyl­ammonium and [tris­(hy­droxy­meth­yl)meth­yl]ammonium, respectively, and on the number and arrangement of the water mol­ecules of crystallization. In both compounds, the H atoms from the coordinating water mol­ecules participate in extensive three-dimensional hydrogen-bonding networks, which link the cluster units both directly and through solvent mol­ecules and, in B, through the ‘tris­’ cation hydroxyl groups. The cation in B also participates in N—H?O hydrogen bonds. A number of C—H?O inter­actions are also observed in both structures. PMID:25878804

  18. Energy dependence of photon-induced K? and K? x-ray production cross-sections for some elements with 42?Z?68 in the energy range 38-80 keV

    NASA Astrophysics Data System (ADS)

    Seven, Sabriye; Erdo?an, Hasan

    2015-12-01

    The energy dependence of photon-induced K? and K? x-ray production cross-sections for Mo, Ru, Pd, In, Sb, Cs, La, Pr, Sm, Tb and Er elements has been studied in the energy range of 38-80 keV with secondary excitation method. K x-ray intensities were measured using Energy Dispersive X-Ray Fluorescence (EDXRF) Spectrometry. The measurements have been made by observing the x-ray emissions, with the help of HPGe detector coupled with a multichannel analyzer. The areas of the K? and K? spectral peaks, as well as the net peak areas, have been determined by a fitting process. The measured K? and K? x-ray production cross-sections have been compared with calculated theoretical values in this energy regime. The results have been plotted versus excitation energy. The present experimental K? and K? x-ray production cross-section values for all the elements were in general agreement with the theoretical values calculated using photoionization cross-sections, fluorescence yields and fractional rates based on Hartree-Slater potentials.

  19. Determination of Specific Forces and Tool Deflections in Micro-milling of Ti-6Al-4V alloy using Finite Element Simulations and Analysis

    SciTech Connect

    Farina, Simone; Ceretti, Elisabetta; Thepsonti, Thanongsak; Oezel, Tugrul

    2011-05-04

    Titanium alloys offer superb properties in strength, corrosion resistance and biocompatibility and are commonly utilized in medical devices and implants. Micro-end milling process is a direct and rapid fabrication method for manufacturing medical devices and implants in titanium alloys. Process performance and quality depend upon an understanding of the relationship between cutting parameters and forces and resultant tool deflections to avoid tool breakage. For this purpose, FE simulations of chip formation during micro-end milling of Ti-6Al-4V alloy with an ultra-fine grain solid carbide two-flute micro-end mill are investigated using DEFORM software.At first, specific forces in tangential and radial directions of cutting during micro-end milling for varying feed advance and rotational speeds have been determined using designed FE simulations for chip formation process. Later, these forces are applied to the micro-end mill geometry along the axial depth of cut in 3D analysis of ABAQUS. Consequently, 3D distributions for tool deflections and von Misses stress are determined. These analyses will yield in establishing integrated multi-physics process models for high performance micro-end milling and a leap-forward to process improvements.

  20. Trace elements in the hair of hemodialysis patients.

    PubMed

    Ochi, Akinobu; Ishimura, Eiji; Tsujimoto, Yoshihiro; Kakiya, Ryusuke; Tabata, Tsutomu; Mori, Katsuhito; Shoji, Tetsuo; Yasuda, Hiroshi; Nishizawa, Yoshiki; Inaba, Masaaki

    2011-11-01

    Trace element disturbance is often observed in hemodialysis patients. While trace element concentrations have been reported in blood samples from hemodialysis patients, they have not been well investigated in scalp hair. In the present study, 22 trace elemental concentrations were measured by inductively coupled plasma-atomic emission spectrometry in the scalp hair of 80 male hemodialysis patients and compared with those of 100 healthy male subjects. In hemodialysis patients, the concentrations of beryllium, arsenic, magnesium, chromium, manganese, iron, selenium, molybdenum, iodine, vanadium, and cobalt were significantly higher than those in healthy subjects, while lead, mercury, copper, germanium, and bromine were significantly lower than those in the former group. No significant differences were observed for lithium, aluminum, cadmium, zinc, boron, or nickel. There were significant positive correlations between the duration of hemodialysis and the magnesium and manganese concentrations. There was a significant negative correlation between cadmium concentration and the duration of hemodialysis. There were significant positive correlations between dialysis efficacy (Kt/V) and magnesium, manganese, zinc, and selenium concentrations. In conclusion, trace element concentrations of the scalp hair are different between hemodialysis patients and healthy subjects. Essential trace elements, such as magnesium, manganese, zinc, and selenium, may be affected by the duration of hemodialysis and Kt/V. PMID:21234813

  1. Search for Standard Model Higgs Boson Production in Association with a $W$ Boson Using a Matrix Element Technique at CDF in $p\\bar{p}$ Collisions at $\\sqrt{s} = 1.96$ TeV

    SciTech Connect

    Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J.A.; Arisawa, T.; Artikov, A.; /Dubna, JINR /Texas A-M

    2011-12-01

    This paper presents a search for standard model Higgs boson production in association with a W boson using events recorded by the CDF experiment in a dataset corresponding to an integrated luminosity of 5.6 fb{sup -1}. The search is performed using a matrix element technique in which the signal and background hypotheses are used to create a powerful discriminator. The discriminant output distributions for signal and background are fit to the observed events using a binned likelihood approach to search for the Higgs boson signal. We find no evidence for a Higgs boson, and 95% confidence level (C.L.) upper limits are set on {sigma}(p{bar p} {yields} WH) x {Beta}(H {yields} b{bar b}). The observed limits range from 3.5 to 37.6 relative to the standard model expectation for Higgs boson masses between m{sub H} = 100 GeV/c{sup 2} and m{sub H} = 150 GeV/c{sup 2}. The 95% C.L. expected limit is estimated from the median of an ensemble of simulated experiments and varies between 2.9 and 32.7 relative to the production rate predicted by the standard model over the Higgs boson mass range studied.

  2. Search for standard model Higgs boson production in association with a W boson using a matrix element technique at CDF in pp? collisions at ?s=1.96 TeV

    SciTech Connect

    Aaltonen, T.; Álvarez González, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J. A.; Arisawa, T.; Artikov, A.; Asaadi, J.; Ashmanskas, W.; Auerbach, B.; Aurisano, A.; Azfar, F.; Badgett, W.; Bae, T.; Barbaro-Galtieri, A.; Barnes, V. E.; Barnett, B. A.; Barria, P.; Bartos, P.; Bauce, M.; Bedeschi, F.; Behari, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Beretvas, A.; Bhatti, A.; Bisello, D.; Bizjak, I.; Bland, K. R.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Bortoletto, D.; Boudreau, J.; Boveia, A.; Brigliadori, L.; Bromberg, C.; Brucken, E.; Budagov, J.; Budd, H. S.; Burkett, K.; Busetto, G.; Bussey, P.; Buzatu, A.; Calamba, A.; Calancha, C.; Camarda, S.; Campanelli, M.; Campbell, M.; Canelli, F.; Carls, B.; Carlsmith, D.; Carosi, R.; Carrillo, S.; Carron, S.; Casal, B.; Casarsa, M.; Castro, A.; Catastini, P.; Cauz, D.; Cavaliere, V.; Cavalli-Sforza, M.; Cerri, A.; Cerrito, L.; Chen, Y. C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Chlebana, F.; Cho, K.; Chokheli, D.; Chung, W. H.; Chung, Y. S.; Ciobanu, C. I.; Ciocci, M. A.; Clark, A.; Clarke, C.; Compostella, G.; Convery, M. E.; Conway, J.; Corbo, M.; Cordelli, M.; Cox, C. A.; Cox, D. J.; Crescioli, F.; Cuevas, J.; Culbertson, R.; Dagenhart, D.; d’Ascenzo, N.; Datta, M.; de Barbaro, P.; Dell’Orso, M.; Demortier, L.; Deninno, M.; Devoto, F.; d’Errico, M.; Di Canto, A.; Di Ruzza, B.; Dittmann, J. R.; D’Onofrio, M.; Donati, S.; Dong, P.; Dorigo, M.; Dorigo, T.; Ebina, K.; Elagin, A.; Eppig, A.; Erbacher, R.; Errede, S.; Ershaidat, N.; Eusebi, R.; Farrington, S.; Feindt, M.; Fernandez, J. P.; Field, R.; Flanagan, G.; Forrest, R.; Frank, M. J.; Franklin, M.; Freeman, J. C.; Funakoshi, Y.; Furic, I.; Gallinaro, M.; Garcia, J. E.; Garfinkel, A. F.; Garosi, P.; Gerberich, H.; Gerchtein, E.; Giagu, S.; Giakoumopoulou, V.; Giannetti, P.; Gibson, K.; Ginsburg, C. M.; Giokaris, N.; Giromini, P.; Giurgiu, G.; Glagolev, V.; Glenzinski, D.; Gold, M.; Goldin, D.; Goldschmidt, N.; Golossanov, A.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; González, O.; Gorelov, I.; Goshaw, A. T.; Goulianos, K.; Grinstein, S.; Grosso-Pilcher, C.; Group, R. C.; Guimaraes da Costa, J.; Hahn, S. R.; Halkiadakis, E.; Hamaguchi, A.; Han, J. Y.; Happacher, F.; Hara, K.; Hare, D.; Hare, M.; Harr, R. F.; Hatakeyama, K.; Hays, C.; Heck, M.; Heinrich, J.; Herndon, M.; Hewamanage, S.; Hocker, A.; Hopkins, W.; Horn, D.; Hou, S.; Hughes, R. E.; Hurwitz, M.; Husemann, U.; Hussain, N.; Hussein, M.; Huston, J.; Introzzi, G.; Iori, M.; Ivanov, A.; James, E.; Jang, D.; Jayatilaka, B.; Jeon, E. J.; Jindariani, S.; Jones, M.; Joo, K. K.; Jun, S. Y.; Junk, T. R.; Kamon, T.; Karchin, P. E.; Kasmi, A.; Kato, Y.; Ketchum, W.; Keung, J.; Khotilovich, V.; Kilminster, B.; Kim, D. H.; Kim, H. S.; Kim, J. E.; Kim, M. J.; Kim, S. B.; Kim, S. H.; Kim, Y. K.; Kim, Y. J.; Kimura, N.; Kirby, M.; Klimenko, S.; Knoepfel, K.; Kondo, K.; Kong, D. J.; Konigsberg, J.; Kotwal, A. V.; Kreps, M.; Kroll, J.; Krop, D.; Kruse, M.; Krutelyov, V.; Kuhr, T.; Kurata, M.; Kwang, S.; Laasanen, A. T.; Lami, S.; Lammel, S.; Lancaster, M.; Lander, R. L.; Lannon, K.; Lath, A.; Latino, G.; LeCompte, T.; Lee, E.; Lee, H. S.; Lee, J. S.; Lee, S. W.; Leo, S.; Leone, S.; Lewis, J. D.; Limosani, A.; Lin, C.-J.; Lindgren, M.; Lipeles, E.; Lister, A.; Litvintsev, D. O.; Liu, C.; Liu, H.; Liu, Q.; Liu, T.; Lockwitz, S.; Loginov, A.; Lucchesi, D.; Lueck, J.; Lujan, P.; Lukens, P.; Lungu, G.; Lys, J.; Lysak, R.; Madrak, R.; Maeshima, K.; Maestro, P.; Malik, S.; Manca, G.; Manousakis-Katsikakis, A.; Margaroli, F.; Marino, C.; Martínez, M.; Mastrandrea, P.; Matera, K.; Mattson, M. E.; Mazzacane, A.; Mazzanti, P.; McFarland, K. S.; McIntyre, P.; McNulty, R.; Mehta, A.; Mehtala, P.; Mesropian, C.; Miao, T.; Mietlicki, D.; Mitra, A.; Miyake, H.; Moed, S.; Moggi, N.; Mondragon, M. N.; Moon, C. S.; Moore, R.; Morello, M. J.; Morlock, J.; Movilla Fernandez, P.; Mukherjee, A.; Muller, Th.; Murat, P.; Mussini, M.; Nachtman, J.; Nagai, Y.; Naganoma, J.; Nakano, I.; Napier, A.; Nett, J.; Neu, C.; Neubauer, M. S.; Nielsen, J.; Nodulman, L.; Noh, S. Y.; Norniella, O.; Oakes, L.; Oh, S. H.; Oh, Y. D.; Oksuzian, I.; Okusawa, T.; Orava, R.; Ortolan, L.; Pagan Griso, S.; Pagliarone, C.; Palencia, E.; Papadimitriou, V.; Paramonov, A. A.; Patrick, J.; Pauletta, G.; Paulini, M.; Paus, C.; Pellett, D. E.; Penzo, A.; Phillips, T. J.; Piacentino, G.; Pianori, E.; Pilot, J.; Pitts, K.; Plager, C.; Pondrom, L.; Poprocki, S.; Potamianos, K.; Prokoshin, F.; Pranko, A.; Ptohos, F.; Punzi, G.; Rahaman, A.; Ramakrishnan, V.; Ranjan, N.; Redondo, I.; Renton, P.; Rescigno, M.; Riddick, T.; Rimondi, F.; Ristori, L.; Robson, A.; Rodrigo, T.; Rodriguez, T.; Rogers, E.; Rolli, S.; Roser, R.; Ruffini, F.; Ruiz, A.; Russ, J.; Rusu, V.; Safonov, A.

    2012-04-02

    This paper presents a search for standard model Higgs boson production in association with a W boson using events recorded by the CDF experiment in a data set corresponding to an integrated luminosity of 5.6 fb?¹. The search is performed using a matrix element technique in which the signal and background hypotheses are used to create a powerful discriminator. The discriminant output distributions for signal and background are fit to the observed events using a binned likelihood approach to search for the Higgs boson signal. We find no evidence for a Higgs boson, and 95% confidence level (C.L.) upper limits are set on ?(pp??WH)×B(H?bb¯). The observed limits range from 3.5 to 37.6 relative to the standard model expectation for Higgs boson masses between mH=100 GeV/c² and mH=150 GeV/c². The 95% C.L. expected limit is estimated from the median of an ensemble of simulated experiments and varies between 2.9 and 32.7 relative to the production rate predicted by the standard model over the Higgs boson mass range studied.

  3. Search for standard model Higgs boson production in association with a W boson using a matrix element technique at CDF in pp? collisions at ?s=1.96 TeV

    DOE PAGESBeta

    Aaltonen, T.; Álvarez González, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J. A.; Arisawa, T.; et al

    2012-04-02

    This paper presents a search for standard model Higgs boson production in association with a W boson using events recorded by the CDF experiment in a data set corresponding to an integrated luminosity of 5.6 fb?¹. The search is performed using a matrix element technique in which the signal and background hypotheses are used to create a powerful discriminator. The discriminant output distributions for signal and background are fit to the observed events using a binned likelihood approach to search for the Higgs boson signal. We find no evidence for a Higgs boson, and 95% confidence level (C.L.) upper limitsmore »are set on ?(pp??WH)×B(H?bb¯). The observed limits range from 3.5 to 37.6 relative to the standard model expectation for Higgs boson masses between mH=100 GeV/c² and mH=150 GeV/c². The 95% C.L. expected limit is estimated from the median of an ensemble of simulated experiments and varies between 2.9 and 32.7 relative to the production rate predicted by the standard model over the Higgs boson mass range studied.« less

  4. Knot Groups with Many Killers

    E-print Network

    Silver, Daniel S; Williams, Susan G

    2009-01-01

    The group of any nontrivial torus knot, hyperbolic 2-bridge knot, or hyperbolic knot with unknotting number one contains infinitely many elements, none the automorphic image of another, such that each normally generates the group.

  5. III-V aresenide-nitride semiconductor materials and devices

    NASA Technical Reports Server (NTRS)

    Major, Jo S. (Inventor); Welch, David F. (Inventor); Scifres, Donald R. (Inventor)

    1997-01-01

    III-V arsenide-nitride semiconductor crystals, methods for producing such crystals and devices employing such crystals. Group III elements are combined with group V elements, including at least nitrogen and arsenic, in concentrations chosen to lattice match commercially available crystalline substrates. Epitaxial growth of these III-V crystals results in direct bandgap materials, which can be used in applications such as light emitting diodes and lasers. Varying the concentrations of the elements in the III-V crystals varies the bandgaps, such that materials emitting light spanning the visible spectra, as well as mid-IR and near-UV emitters, can be created. Conversely, such material can be used to create devices that acquire light and convert the light to electricity, for applications such as full color photodetectors and solar energy collectors. The growth of the III-V crystals can be accomplished by growing thin layers of elements or compounds in sequences that result in the overall lattice match and bandgap desired.

  6. Correlation of trace elements in hair with colon cancer

    SciTech Connect

    Kwiatek, W.M.; Cholewa, M.; Kajfosz, J.; Jones, K.W.; Shore, R.E.; Redrick, A.L.

    1986-01-01

    The trace element content of 116 hair samples from patients with colon cancer and from referent series of patients who had a variety of other diseases were measured using proton-induced x-ray emission (PIXE). The patients had been on largely uncontrolled diets, and the interest was whether there were differences in trace element concentrations attributable to the effects of colon cancer. The concentrations of K, Ca, Mn, Fe, Cu, Zn, Se, Br, and Rb were determined using a beam of 2.5-MeV protons. Minimum detectable limits (MDL) of 0.3 ppM were obtained for Zn and Se. Cluster analysis of the data set did not reveal any significant differences between the cancer and control groups. Mean values and ranges obtained for the elemental concentrations show good agreement with other published determinations. 20 refs., 3 figs., 3 tabs.

  7. Glueball matrix elements: a lattice calculation and applications

    E-print Network

    Harvey B. Meyer

    2008-08-22

    We compute the matrix elements of the energy-momentum tensor between glueball states and the vacuum in SU(3) lattice gauge theory and extrapolate them to the continuum. These matrix elements may play an important phenomenological role in identifying glue-rich mesons. Based on a relation derived long ago by the ITEP group for J/psi radiative decays, the scalar matrix element leads to a branching ratio for the glueball that is at least three times larger than the experimentally observed branching ratio for the f_0 mesons above 1GeV. This suggests that the glueball component must be diluted quite strongly among the known scalar mesons. Finally we review the current best continuum determination of the scalar and tensor glueball masses, the deconfining temperature, the string tension and the Lambda parameter, all in units of the Sommer reference scale, using calculations based on the Wilson action.

  8. Mercury, elemental

    Integrated Risk Information System (IRIS)

    Mercury , elemental ; CASRN 7439 - 97 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinoge

  9. Element Research.

    ERIC Educational Resources Information Center

    Herald, Christine

    2001-01-01

    Describes a research assignment for 8th grade students on the elements of the periodic table. Students use web-based resources and a chemistry handbook to gather information, construct concept maps, and present the findings to the full class using the mode of their choice: a humorous story, a slideshow or gameboard, a brochure, a song, or skit.…

  10. RADIATIVE LIFETIMES OF V I AND V II

    SciTech Connect

    Den Hartog, E. A.; Lawler, J. E.; Wood, M. P. E-mail: jelawler@wisc.edu

    2014-11-01

    New radiative lifetimes are reported for 168 levels of V I ranging in energy from 18086 cm{sup –1} to 47702 cm{sup –1}, and for 31 levels of V II ranging in energy from 34593 cm{sup –1} to 47420 cm{sup –1}. These lifetimes are measured using time-resolved laser-induced fluorescence on a slow atomic/ionic beam as part of an ongoing study of the radiative properties of the iron group elements. All but two of the V II lifetimes have been measured before using modern laser-based methods, but a large fraction of the V I lifetimes are reported here for the first time. Comparison to earlier measurements is discussed. These new lifetimes are, for the most part, accurate to ±5%. They will be combined with branching fraction measurements to produce a large set of transition probabilities for V I and V II which are needed by the astrophysics community for stellar abundance determinations.

  11. microRNA miR-142-3p Inhibits Breast Cancer Cell Invasiveness by Synchronous Targeting of WASL, Integrin Alpha V, and Additional Cytoskeletal Elements

    PubMed Central

    Schwickert, Alexander; Weghake, Esther; Brüggemann, Kathrin; Engbers, Annika; Brinkmann, Benjamin F.; Kemper, Björn; Seggewiß, Jochen; Stock, Christian; Ebnet, Klaus; Kiesel, Ludwig; Riethmüller, Christoph; Götte, Martin

    2015-01-01

    MicroRNAs (miRNAs, micro ribonucleic acids) are pivotal post-transcriptional regulators of gene expression. These endogenous small non-coding RNAs play significant roles in tumorigenesis and tumor progression. miR-142-3p expression is dysregulated in several breast cancer subtypes. We aimed at investigating the role of miR-142-3p in breast cancer cell invasiveness. Supported by transcriptomic Affymetrix array analysis and confirmatory investigations at the mRNA and protein level, we demonstrate that overexpression of miR-142-3p in MDA-MB-231, MDA-MB-468 and MCF-7 breast cancer cells leads to downregulation of WASL (Wiskott-Aldrich syndrome-like, protein: N-WASP), Integrin-?V, RAC1, and CFL2, molecules implicated in cytoskeletal regulation and cell motility. ROCK2, IL6ST, KLF4, PGRMC2 and ADCY9 were identified as additional targets in a subset of cell lines. Decreased Matrigel invasiveness was associated with the miR-142-3p-induced expression changes. Confocal immunofluorescence microscopy, nanoscale atomic force microscopy and digital holographic microscopy revealed a change in cell morphology as well as a reduced cell volume and size. A more cortical actin distribution and a loss of membrane protrusions were observed in cells overexpressing miR-142-3p. Luciferase activation assays confirmed direct miR-142-3p-dependent regulation of the 3’-untranslated region of ITGAV and WASL. siRNA-mediated depletion of ITGAV and WASL resulted in a significant reduction of cellular invasiveness, highlighting the contribution of these factors to the miRNA-dependent invasion phenotype. While knockdown of WASL significantly reduced the number of membrane protrusions compared to controls, knockdown of ITGAV resulted in a decreased cell volume, indicating differential contributions of these factors to the miR-142-3p-induced phenotype. Our data identify WASL, ITGAV and several additional cytoskeleton-associated molecules as novel invasion-promoting targets of miR-142-3p in breast cancer. PMID:26657485

  12. An Improved Method of Capturing the Surface Boundary of a Ti-6Al-4V Fusion Weld Bead for Finite Element Modeling

    NASA Astrophysics Data System (ADS)

    Turner, R. P.; Villa, M.; Sovani, Y.; Panwisawas, C.; Perumal, B.; Ward, R. M.; Brooks, J. W.; Basoalto, H. C.

    2015-10-01

    Weld simulation methods have often employed mathematical functions to describe the size and shape of the molten pool of material transiently present in a weld. However, while these functions can sometimes accurately capture the fusion boundary for certain welding parameters in certain materials, they do not necessarily offer a robust methodology for the more intricate weld pool shapes that can be produced in materials with a very low thermal conductivity, such as the titanium alloy Ti-6Al-4V. Cross-sections of steady-state welds can be observed which contain a dramatic narrowing of the pool width at roughly half way in to the depth of the plate of material, and a significant widening again at the base. These effects on the weld pool are likely to do with beam focusing height. However, the resultant intricacy of the pool means that standard formulaic methods to capture the shape may prove relatively unsuccessful. Given how critical the accuracy of pool shape is in determining the mechanical response to the heating, an alternative method is presented. By entering weld pool width measurements for a series of depths in a Cartesian co-ordinate system using FE weld simulation software Sysweld, a more representative weld pool size and shape can be predicted, compared to the standard double ellipsoid method. Results have demonstrated that significant variations in the mid-depth thermal profile are observed between the two, even though the same values for top and bottom pool-widths are entered. Finally, once the benefits of the Cartesian co-ordinate method are demonstrated, the robustness of this approach to predict a variety of weld pool shapes has been demonstrated upon a series of nine weld simulations, where the two key process parameters (welding laser power and travel speed) are explored over a design space ranging from 1.5 to 3 kW and 50 to 200 mm/s. Results suggest that for the faster travel speeds, the more detailed Cartesian co-ordinate method is better, whereas for slower welds, the traditional double ellipsoid function captures the fusion boundary as successfully as the Cartesian method, and in faster computation times.

  13. Highly siderophile elements in chondrites

    USGS Publications Warehouse

    Horan, M.F.; Walker, R.J.; Morgan, J.W.; Grossman, J.N.; Rubin, A.E.

    2003-01-01

    The abundances of the highly siderophile elements (HSE), Re, Os, Ir, Ru, Pt and Pd, were determined by isotope dilution mass spectrometry for bulk samples of 13 carbonaceous chondrites, 13 ordinary chondrites and 9 enstatite chondrites. These data are coupled with corresponding 187Re-187Os isotopic data reported by Walker et al. [Geochim. Cosmochim. Acta, 2002] in order to constrain the nature and timing of chemical fractionation relating to these elements in the early solar system. The suite of chondrites examined displays considerable variations in absolute abundances of the HSE, and in the ratios of certain HSE. Absolute abundances of the HSE vary by nearly a factor of 80 among the chondrite groups, although most vary within a factor of only 2. Variations in concentration largely reflect heterogeneities in the sample aliquants. Different aliquants of the same chondrite may contain variable proportions of metal and/or refractory inclusions that are HSE-rich, and sulfides that are HSE-poor. The relatively low concentrations of the HSE in CI1 chondrites likely reflect dilution by the presence of volatile components. Carbonaceous chondrites have Re/Os ratios that are, on average, approximately 8% lower than ratios for ordinary and enstatite chondrites. This is also reflected in 187Os/188Os ratios that are approximately 3% lower for carbonaceous chondrites than for ordinary and enstatite chondrites. Given the similarly refractory natures of Re and Os, this fractionation may have occurred within a narrow range of high temperatures, during condensation of these elements from the solar nebula. Superimposed on this major fractionation are more modest movements of Re or Os that occurred within the last 0-2 Ga, as indicated by minor open-system behavior of the Re-Os isotope systematics of some chondrites. The relative abundances of other HSE can also be used to discriminate among the major classes of chondrites. For example, in comparison to the enstatite chondrites, carbonaceous and ordinary chondrites have distinctly lower ratios of Pd to the more refractory HSE (Re, Os, Ir, Ru and Pt). Differences are particularly well resolved for the EH chondrites that have Pd/Ir ratios that average more than 40% higher than for carbonaceous and ordinary chondrite classes. This fractionation probably occurred at lower temperatures, and may be associated with fractionation processes that also affected the major refractory lithophile elements. Combined, 187Os/188Os ratios and HSE ratios reflect unique early solar system processing of HSE for each major chondrite class. ?? 2002 Elsevier Science B.V. All rights reserved.

  14. Structural Truss Elements and Forces

    ERIC Educational Resources Information Center

    Troyer, Steve; Griffis, Kurt; Shackelford, Ray

    2005-01-01

    In the field of construction, most structures are supported by several groups of truss systems working together synergistically. A "truss" is a group of centered and balanced elements combined to carry a common load (Warner, 2003). Trusses provide strength against loads and forces within a structure. Though a complex field of study, structural…

  15. Elemental evidence

    NASA Astrophysics Data System (ADS)

    Carlowicz, Michael

    He set out to prove that ocean sediments contain elevated levels of the rare element iridium because of the natural weathering of the continents. Instead, what Ariel Anbar found was new evidence that a meteorite may have had a role in the mass extinctions that marked the end of the Cretaceous era.By studying the geochemical properties of iridium, Anbar, a professor of earth and environmental sciences and chemistry at the University of Rochester, found that the residence time—a measure of the rate at which an element settles out of water into sediments—of iridium in ocean water is 2000 to 20,000 years. That finding suggests that a large deposit of iridium could have lingered in the world's oceans long enough to explain the thickness of the iridium-rich sediment layers at the K-T boundary.

  16. Variable contribution of functional prey groups in diets reveals inter- and intraspecific differences in faecal concentrations of essential and non-essential elements in three sympatric avian aerial insectivores: a re-assessment of usefulness of bird faeces in metal biomonitoring.

    PubMed

    Or?owski, Grzegorz; Kami?ski, Piotr; Karg, Jerzy; Baszy?ski, J?drzej; Szady-Grad, Ma?gorzata; Koim-Puchowska, Beata; Klawe, Jacek J

    2015-06-15

    Aerial insectivores through their insect diet can contribute to biotransfer of elements across habitats. We investigate the relationship between dietary composition as expressed by the contributions of six functional invertebrate prey groups (primarily of agriculturally subsidised invertebrates characteristic of agricultural areas in temperate regions of Europe) and concentrations of essential (Na, K, Ca, Mg, Fe, Cu, Zn, Mn, Co) and non-essential (As, Cd, Pb) elements of environmental concern in the faeces of nestlings of three species of avian aerial insectivores - Common Swift Apus apus, Barn Swallow Hirundo rustica and House Martin Delichon urbicum - which breed sympatrically and use apparently similar resources of flying insect prey. There were significant differences between the species for 7 of the 12 elements (Ca, Zn, Cu, Co, As, Pb, Cd); these differences were attributable to the variable dietary composition, even though the concentrations of the elements varied enormously between the faecal samples from the individual species. Partial correlation analysis between the biomass (expressed in mg dry weight) of the six functional prey groups and faecal concentrations of elements showed the highest number of significant relationships for toxic metals (As, Pb and Cd). The results of the General Regression Model explaining faecal element concentrations revealed the different explanatory power of the effects of PCA (of six functional prey groups) dietary scores. A significant fit of GRM was obtained for 7 elements (Na, Mg, Fe, Mn, As, Pb, Cd) for Barn Swallows, 2 elements (Cu, As) for House Martins and 1 element (Mn) for Common Swifts. Overall, the results confirmed our predictions that the biomass of consumed coprophilous taxa and insects from crop habitats was positively correlated with the faecal concentrations of toxic elements. Unexpectedly, however, the faecal samples (primarily those of Common Swifts) that contained many oil-seed rape insect pests had lower Ca, Pb and Cd levels and a higher As level. Our study implies that the cross-boundary transfer of contaminants, primarily non-essential elements, by aerially foraging birds through the considerable accumulation of their faeces has potential consequences for the local biogeochemical cycle and environmental quality. PMID:25770953

  17. Trends in Ionization Energy of Transition-Metal Elements

    ERIC Educational Resources Information Center

    Matsumoto, Paul S.

    2005-01-01

    A rationale for the difference in the periodic trends in the ionization energy of the transition-metal elements versus the main-group elements is presented. The difference is that in the transition-metal elements, the electrons enter an inner-shell electron orbital, while in the main-group elements, the electrons enter an outer-shell electron…

  18. Variations of trace element concentration of magnetite and ilmenite from the Taihe layered intrusion, Emeishan large igneous province, SW China: Implications for magmatic fractionation and origin of Fe-Ti-V oxide ore deposits

    NASA Astrophysics Data System (ADS)

    She, Yu-Wei; Song, Xie-Yan; Yu, Song-Yue; He, Hai-Long

    2015-12-01

    In situ LA-ICP-MS trace elemental analysis has been applied to magnetite and ilmenite of the Taihe layered intrusion, Emeishan large igneous province, SW China, in order to understand better fractionation processes of magma and origin of Fe-Ti-V oxide ore deposits. The periodic reversals in Mg, Ti, Mn in magnetite and Mg, Sc in ilmenite are found in the Middle Zone of the intrusion and agree with fractionation trends as recorded by olivine (Fo), plagioclase (An) and clinopyroxene (Mg#) compositions. These suggest the Taihe intrusion formed from open magma chamber processes in a magma conduit with multiple replenishments of more primitive magmas. The V and Cr of magnetite are well correlated with V and Cr of clinopyroxene indicating that they became liquidus phases almost simultaneously at an early stage of magma evolution. Ilmenite from the Middle and Upper Zones shows variable Cr, Ni, V, Mg, Nb, Ta and Sc contents indicating that ilmenite at some stratigraphic levels crystallized slightly earlier than magnetite and clinopyroxene. The early crystallization of magnetite and ilmenite is the result of the high FeOt and TiO2 contents in the parental magma. The ilmenite crystallization before magnetite in the Middle and Upper Zones can be attributed to higher TiO2 content of the magma due to the remelting of pre-existing ilmenite in a middle-level magma chamber. Compared to the coeval high-Ti basalts, the relatively low Zr, Hf, Nb and Ta contents in both magnetite and ilmenite throughout the Taihe intrusion indicate that they crystallized from Fe-Ti-(P)-rich silicate magmas. Positive correlations of Ti with Mg, Mn, Sc and Zr of magnetite, and Zr with Sc, Hf and Nb of ilmenite also suggest that magnetite and ilmenite crystallized continuously from the homogeneous silicate magma rather than an immiscible Fe-rich melt. Therefore, frequent replenishments of Fe-Ti-(P)-rich silicate magma and gravitational sorting and settling are crucial for the formation the massive and apatite-rich disseminated ores in the Lower and Middle Zones of the Taihe intrusion.

  19. CORRIGENDUM CLONES OF FINITE GROUPS

    E-print Network

    Kearnes, Keith A.

    CORRIGENDUM CLONES OF FINITE GROUPS KEITH A. KEARNES AND ´AGNES SZENDREI 1. The Clone of the Quaternion Group We proved in Clones of finite groups, [1], that any operation on the 8-element quaternion group Q8 that preserves all the 5-ary algebraic relations of Q8 is in the clone of Q8

  20. arXiv:1110.3304v1[math.AT]14Oct2011 A Cocycle Model for for Topological and Lie Group Cohomology

    E-print Network

    Wagemann, Friedrich

    Friedrich Wagemann wagemann@math.univ-nantes.fr Christoph Wockel christoph@wockel.eu October 17, 2011 from. The basic message will be that all the above concepts of topological and Lie group cohomology

  1. Chemistry of the superheavy elements.

    PubMed

    Schädel, Matthias

    2015-03-13

    The quest for superheavy elements (SHEs) is driven by the desire to find and explore one of the extreme limits of existence of matter. These elements exist solely due to their nuclear shell stabilization. All 15 presently 'known' SHEs (11 are officially 'discovered' and named) up to element 118 are short-lived and are man-made atom-at-a-time in heavy ion induced nuclear reactions. They are identical to the transactinide elements located in the seventh period of the periodic table beginning with rutherfordium (element 104), dubnium (element 105) and seaborgium (element 106) in groups 4, 5 and 6, respectively. Their chemical properties are often surprising and unexpected from simple extrapolations. After hassium (element 108), chemistry has now reached copernicium (element 112) and flerovium (element 114). For the later ones, the focus is on questions of their metallic or possibly noble gas-like character originating from interplay of most pronounced relativistic effects and electron-shell effects. SHEs provide unique opportunities to get insights into the influence of strong relativistic effects on the atomic electrons and to probe 'relativistically' influenced chemical properties and the architecture of the periodic table at its farthest reach. In addition, they establish a test bench to challenge the validity and predictive power of modern fully relativistic quantum chemical models. PMID:25666065

  2. Using gene expression profiling to evaluate cellular responses in mouse lungs exposed to V2O5 and a group of other mouse lung tumorigens and non-tumorigens.

    PubMed

    Black, Michael B; Dodd, Darol E; McMullen, Patrick D; Pendse, Salil; MacGregor, Judith A; Gollapudi, B Bhaskar; Andersen, Melvin E

    2015-10-01

    Many compounds test positive for lung tumors in two-year NTP carcinogenicity bioassays in B6C3F1 mice. V2O5 was identified as a lung carcinogen in this assay, leading to its IARC (International Agency for Research on Cancer) classification as group 2b or a "possible" human carcinogen. To assess potential tumorigenic mode of action of V2O5, we compared gene expression and gene ontology enrichment in lung tissue of female B6C3F1 mice exposed for 13 weeks to a V2O5 particulate aerosol at a tumorigenic level (2.0 mg/m(3)). Relative to 12 other compounds also tested for carcinogenicity in 2-year bioassays in mice, there were 1026 differentially expressed genes with V2O5, of which 483 were unique to V2O5. Ontology analysis of the 1026 V2O5 differentially expressed genes showed enrichment for hyaluronan and sphingolipid metabolism, adenylate cyclase functions, c-AMP signaling and PKA activation/signaling. Enrichment of lipids/lipoprotein metabolism and inflammatory pathways were consistent with previously reported clinical findings. Enrichment of c-AMP and PKA signaling pathways may arise due to inhibition of phosphatases, a known biological action of vanadate. We saw no enrichment for DNA-damage, oxidative stress, cell cycle, or apoptosis pathway signaling in mouse lungs exposed to V2O5 which is in contrast with past studies evaluating in vivo gene expression in target tissues of other carcinogens (arsenic, formaldehyde, naphthalene and chloroprene). PMID:26210822

  3. Intelligent Elements for ISHM

    NASA Technical Reports Server (NTRS)

    Schmalzel, John L.; Morris, Jon; Turowski, Mark; Figueroa, Fernando; Oostdyk, Rebecca

    2008-01-01

    There are a number of architecture models for implementing Integrated Systems Health Management (ISHM) capabilities. For example, approaches based on the OSA-CBM and OSA-EAI models, or specific architectures developed in response to local needs. NASA s John C. Stennis Space Center (SSC) has developed one such version of an extensible architecture in support of rocket engine testing that integrates a palette of functions in order to achieve an ISHM capability. Among the functional capabilities that are supported by the framework are: prognostic models, anomaly detection, a data base of supporting health information, root cause analysis, intelligent elements, and integrated awareness. This paper focuses on the role that intelligent elements can play in ISHM architectures. We define an intelligent element as a smart element with sufficient computing capacity to support anomaly detection or other algorithms in support of ISHM functions. A smart element has the capabilities of supporting networked implementations of IEEE 1451.x smart sensor and actuator protocols. The ISHM group at SSC has been actively developing intelligent elements in conjunction with several partners at other Centers, universities, and companies as part of our ISHM approach for better supporting rocket engine testing. We have developed several implementations. Among the key features for these intelligent sensors is support for IEEE 1451.1 and incorporation of a suite of algorithms for determination of sensor health. Regardless of the potential advantages that can be achieved using intelligent sensors, existing large-scale systems are still based on conventional sensors and data acquisition systems. In order to bring the benefits of intelligent sensors to these environments, we have also developed virtual implementations of intelligent sensors.

  4. Evidence for single top-quark production in the $s$-channel in proton-proton collisions at $\\sqrt{s}=$8 TeV with the ATLAS detector using the Matrix Element Method

    E-print Network

    ATLAS Collaboration

    2015-11-18

    This Letter presents evidence for single top-quark production in the $s$-channel using proton-proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS detector at the CERN Large Hadron Collider. The analysis is performed on events containing one isolated electron or muon, large missing transverse momentum and exactly two $b$-tagged jets in the final state. The analysed data set corresponds to an integrated luminosity of 20.3 fb$^{-1}$. The signal is extracted using a maximum-likelihood fit of a discriminant which is based on the matrix element method and optimized in order to separate single-top-quark $s$-channel events from the main background contributions, which are top-quark pair production and $W$ boson production in association with heavy-flavour jets. The measurement leads to an observed signal significance of 3.2 standard deviations and a measured cross-section of $\\sigma_s=4.8\\pm0.8$(stat.)$^{+1.6}_{-1.3}$(syst.) pb, which is consistent with the Standard Model expectation. The expected significance for the analysis is 3.9 standard deviations.

  5. Iron and s-elements abundance variations in NGC 5286: comparison with `anomalous' globular clusters and Milky Way satellites

    NASA Astrophysics Data System (ADS)

    Marino, A. F.; Milone, A. P.; Karakas, A. I.; Casagrande, L.; Yong, D.; Shingles, L.; Da Costa, G.; Norris, J. E.; Stetson, P. B.; Lind, K.; Asplund, M.; Collet, R.; Jerjen, H.; Sbordone, L.; Aparicio, A.; Cassisi, S.

    2015-06-01

    We present a high-resolution spectroscopic analysis of 62 red giants in the Milky Way globular cluster (GC) NGC 5286. We have determined abundances of representative light proton-capture, ?, Fe-peak and neutron-capture element groups, and combined them with photometry of multiple sequences observed along the colour-magnitude diagram. Our principal results are: (i) a broad, bimodal distribution in s-process element abundance ratios, with two main groups, the s-poor and s-rich groups; (ii) substantial star-to-star Fe variations, with the s-rich stars having higher Fe, e.g. < [Fe/H]> _{s-rich}} - < [Fe/H]> _{s-poor}} ˜ 0.2 dex; and (iii) the presence of O-Na-Al (anti)correlations in both stellar groups. We have defined a new photometric index, cBVI = (B - V) - (V - I), to maximize the separation in the colour-magnitude diagram between the two stellar groups with different Fe and s-element content, and this index is not significantly affected by variations in light elements (such as the O-Na anticorrelation). The variations in the overall metallicity present in NGC 5286 add this object to the class of anomalous GCs. Furthermore, the chemical abundance pattern of NGC 5286 resembles that observed in some of the anomalous GCs, e.g. M 22, NGC 1851, M 2, and the more extreme ? Centauri, that also show internal variations in s-elements, and in light elements within stars with different Fe and s-elements content. In view of the common variations in s-elements, we propose the term s-Fe-anomalous GCs to describe this sub-class of objects. The similarities in chemical abundance ratios between these objects strongly suggest similar formation and evolution histories, possibly associated with an origin in tidally disrupted dwarf satellites.

  6. Transpositionally active episomal hAT elements

    PubMed Central

    2009-01-01

    Background hAT elements and V(D)J recombination may have evolved from a common ancestral transposable element system. Extrachromosomal, circular forms of transposable elements (referred to here as episomal forms) have been reported yet their biological significance remains unknown. V(D)J signal joints, which resemble episomal transposable elements, have been considered non-recombinogenic products of V(D)J recombination and a safe way to dispose of excised chromosomal sequences. V(D)J signal joints can, however, participate in recombination reactions and the purpose of this study was to determine if hobo and Hermes episomal elements are also recombinogenic. Results Up to 50% of hobo/Hermes episomes contained two intact, inverted-terminal repeats and 86% of these contained from 1-1000 bp of intercalary DNA. Episomal hobo/Hermes elements were recovered from Musca domestica (a natural host of Hermes), Drosophila melanogaster (a natural host of hobo) and transgenic Drosophila melanogaster and Aedes aegypti (with autonomous Hermes elements). Episomal Hermes elements were recovered from unfertilized eggs of M. domestica and D. melanogaster demonstrating their potential for extrachromosomal, maternal transmission. Reintegration of episomal Hermes elements was observed in vitro and in vivo and the presence of Hermes episomes resulted in lower rates of canonical Hermes transposition in vivo. Conclusion Episomal hobo/Hermes elements are common products of element excision and can be maternally transmitted. Episomal forms of Hermes are capable of integration and also of influencing the transposition of canonical elements suggesting biological roles for these extrachromosomal elements in element transmission and regulation. PMID:20003420

  7. Alkali metal and rare earth element evolution of rock-forming minerals from the Gatumba area pegmatites (Rwanda): Quantitative assessment of crystal-melt fractionation in the regional zonation of pegmatite groups

    NASA Astrophysics Data System (ADS)

    Hulsbosch, Niels; Hertogen, Jan; Dewaele, Stijn; André, Luc; Muchez, Philippe

    2014-05-01

    This study presents a general model for the evaluation of Rayleigh fractional crystallisation as the principal differentiation mechanism in the formation of regionally zoned common and rare-element pegmatites. The magmatic evolution of these systems from a granitic source is reconstructed by means of alkali element and rare earth element (REE) analyses of rock-forming minerals (feldspars, micas and tourmaline), which represent a whole sequence of regional pegmatite zonation. The Gatumba pegmatite field (Rwanda, Central Africa) is chosen as case study area because of its well-developed regional zonation sequence. The pegmatites are spatially and temporally related to peraluminous G4-granites (986 ± 10 Ma). The regional zonation is developed around a G4-granite and the proximal pegmatites grade outwardly into biotite, two-mica and muscovite pegmatites. Rare-element (Nb-Ta-Sn) pegmatites occur most distal from the granite.

  8. Finite reflection groups q, t-Fu-Catalan numbers for real reflection groups

    E-print Network

    Faridi, Sara

    , UQAM #12;Finite reflection groups q, t-FuÃ?-Catalan numbers for real reflection groups Algebraic-FuÃ?-Catalan numbers for complex reflection groups #12;#12;Finite real reflection groups Let V be a finite-dimensional real vector space. A (finite) real reflection group W = t1, . . . , t O(V ) is a finite group

  9. The Gifted Group at Mid-Life; Thirty-Five Years' Follow-Up of the Superior Child. Genetic Studies of Genius, Volume V.

    ERIC Educational Resources Information Center

    Terman, Lewis M., Ed.

    The 35 years' followup of the Terman investigation on the gifted child is presented. In order to describe the gifted group of mid-life, a general information blank was mailed in 1950 (1,437 subjects) and in 1955 (1,424 subjects). The field study, completed in 1952, included personal interviews, the Concept Mastery Test, supplementary…

  10. Hyperreflection groups

    E-print Network

    Radcliffe, David G

    2010-01-01

    We introduce the concept of hyperreflection groups, which are a generalization of Coxeter groups. We prove the Deletion and Exchange Conditions for hyperreflection groups, and we discuss special subgroups and fundamental sectors of hyperreflection groups. In the second half of the paper, we prove that Coxeter groups and graph products of groups are examples of hyperreflection groups.

  11. A new X-ray sensitive CHO cell mutant of ionizing radiation group 7,XR-C2, that is defective in DSB repair but has only a mild defect in V(D)J recombination.

    PubMed

    Errami, A; Overkamp, W J; He, D M; Friedl, A A; Gell, D A; Eckardt-Schupp, F; Jackson, S P; Hendrickson, E A; Lohman, P H; Zdzienicka, M Z

    2000-09-15

    The DNA-dependent protein kinase (DNA-PK) complex plays a key role in DNA double-strand break (DSB) repair and V(D)J recombination. Using a genetic approach we have isolated cell mutants sensitive to ionizing radiation (IR) in the hope of elucidating the mechanism and components required for these pathways. We describe here, an X-ray-sensitive and DSB repair defective Chinese hamster ovary (CHO) cell line, XR-C2, which was assigned to the X-Ray Cross Complementation (XRCC) group 7. This group of mutants is defective in the XRCC7/SCID/Prkdc gene, which encodes the catalytic subunit of DNA-PK (DNA-PKcs). Despite the fact that XR-C2 cells expressed normal levels of DNA-PKcs protein, no DNA-PK catalytic activity could be observed in XR-C2, confirming the genetic analyses that these cells harbor a dysfunctional gene for DNA-PKcs. In contrast to other IR group 7 mutants, which contain undetectable or low levels of DNA-PKcs protein and which show a severe defect in V(D)J recombination, XR-C2 cells manifested only a mild defect in both coding and signal junction formation. The unique phenotype of the XR-C2 mutant suggests that a normal level of kinase activity is critical for radiation resistance but not for V(D)J recombination, whereas the overall structure of the DNA-PKcs protein appears to be of great importance for this process. PMID:10980412

  12. THE ZURICH ENVIRONMENTAL STUDY (ZENS) OF GALAXIES IN GROUPS ALONG THE COSMIC WEB. V. PROPERTIES AND FREQUENCY OF MERGING SATELLITES AND CENTRALS IN DIFFERENT ENVIRONMENTS

    SciTech Connect

    Pipino, A.; Cibinel, A.; Tacchella, S.; Carollo, C. M.; Lilly, S. J.; Miniati, F.; Silverman, J. D.; Van Gorkom, J. H.; Finoguenov, A.

    2014-12-20

    We use the Zurich Environmental Study database to investigate the environmental dependence of the merger fraction ? and merging galaxy properties in a sample of ?1300 group galaxies with M > 10{sup 9.2} M {sub ?} and 0.05 < z < 0.0585. In all galaxy mass bins investigated in our study, we find that ? decreases by a factor of ?2-3 in groups with halo masses M {sub HALO} > 10{sup 13.5} M {sub ?} relative to less massive systems, indicating a suppression of merger activity in large potential wells. In the fiducial case of relaxed groups only, we measure a variation of ??/?log (M {sub HALO}) ? –0.07 dex{sup –1}, which is almost independent of galaxy mass and merger stage. At galaxy masses >10{sup 10.2} M {sub ?}, most mergers are dry accretions of quenched satellites onto quenched centrals, leading to a strong increase of ? with decreasing group-centric distance at these mass scales. Both satellite and central galaxies in these high-mass mergers do not differ in color and structural properties from a control sample of nonmerging galaxies of equal mass and rank. At galaxy masses of <10{sup 10.2} M {sub ?} where we mostly probe satellite-satellite pairs and mergers between star-forming systems close pairs (projected distance <10-20 kpc) show instead ?2 × enhanced (specific) star formation rates and ?1.5 × larger sizes than similar mass, nonmerging satellites. The increase in both size and star formation rate leads to similar surface star formation densities in the merging and control-sample satellite populations.

  13. Planets Around Low-Mass Stars (PALMS). V. Age-Dating Low-Mass Companions to Members and Interlopers of Young Moving Groups

    E-print Network

    Bowler, Brendan P; Liu, Michael C; Schlieder, Joshua E; Mann, Andrew W; Dupuy, Trent J; Hinkley, Sasha; Crepp, Justin R; Johnson, John Asher; Howard, Andrew W; Flagg, Laura; Weinberger, Alycia J; Aller, Kimberly M; Allers, Katelyn N; Best, William M J; Kotson, Michael C; Montet, Benjamin T; Herczeg, Gregory J; Baranec, Christoph; Riddle, Reed; Law, Nicholas M; Nielsen, Eric L; Wahhaj, Zahed; Biller, Beth A; Hayward, Thomas L

    2015-01-01

    We present optical and near-infrared adaptive optics (AO) imaging and spectroscopy of 13 ultracool (>M6) companions to late-type stars (K7-M4.5), most of which have recently been identified as candidate members of nearby young moving groups (YMGs; 8-120 Myr) in the literature. The inferred masses of the companions (~10-100 Mjup) are highly sensitive to the ages of the primary stars so we critically examine the kinematic and spectroscopic properties of each system to distinguish bona fide YMG members from old field interlopers. 2MASS J02155892-0929121 C is a new M7 substellar companion (40-60 Mjup) with clear spectroscopic signs of low gravity and hence youth. The primary, possibly a member of the ~40 Myr Tuc-Hor moving group, is visually resolved into three components, making it a young low-mass quadruple system in a compact (1 Gyr) tidally-locked spectroscopic binaries without convincing kinematic associations with any known moving group. The high rate of false positives in the form of old active stars with ...

  14. Designing a new class of III-IV-V semiconductor nanosheets

    NASA Astrophysics Data System (ADS)

    Bhattacharya, A.; Chakrabarty, S.; Das, G. P.

    2013-02-01

    Following the discovery of graphene, a large number of III-V materials such as BN which are isostructural but having contrasting physical properties have drawn attention. Alloying these group III-V parent compounds with a group IV element leads to some novel III-IV-V composites, such as BC2N, whose structure and properties have been studied. Here we report, based on our first principles calculations, a family of III-IV-V nano-sheets that have higher stabilities (cohesive energy) as compared to their corresponding III-V counterparts. These sheets are direct gap semiconductors with their band gaps lying between 0.3-0.8 eV. Our phonon calculations on these sheets show that all their phonon modes are ?-centered and positive which suggest their inherent stability.

  15. The influence of combined magnesium and vanadate administration on the level of some elements in selected rat organs: V-Mg interactions and the role of iron-essential protein (DMT-1) in the mechanism underlying altered tissues iron level.

    PubMed

    Scibior, Agnieszka; Adamczyk, Agnieszka; Go??biowska, Dorota; Nied?wiecka, Irmina; Fornal, Emilia

    2014-04-01

    The effect of 12 week co-administration of sodium metavanadate (SMV) and magnesium sulfate (MS) on the levels of some elements in selected rats' organs and an attempt to elucidate a role of divalent metal transporter 1 (DMT-1) in the mechanism(s) of the SMV-induced disorders in some tissue Fe homeostasis were studied. SMV taken up separately or in combination with MS may pose a risk of the rise and shortage of the total hepatic and splenic Fe and Cu contents, respectively, cerebral Fe deficiency, splenic Ca deposition, and the hepatic, renal, and cerebral DMT-1 down-regulation. When administered alone, SMV may also cause the decrease in the total renal Fe and Cu contents. A visible protective effect of Mg against the renal and cerebral V accumulation and the decrease in the renal Fe and Cu contents during the SMV-MS co-administration together with our previous findings suggest a beneficial role of Mg at SMV exposure. Further, the SMV-induced fall in total iron binding capacity (TIBC), reported previously, and its correlations with the hepatic, splenic, and cerebral Fe levels allow us to suggest that diminished TIBC could be partly involved in the mechanism(s) responsible for the dramatic redistribution of Fe in those tissues. Finally, DMT-1, which potentially could participate in the hepatic non-transferrin Fe-bound uptake, does not play a significant role in this process indicating the need for studying other Fe transporters to more precisely elucidate molecular mechanism(s) underlying the hepatic Fe loading in our experimental conditions. PMID:24549458

  16. Incorporation of platinum-group elements and cobalt into subsidiary pyrite in alkalic Cu-Au porphyry deposits: significant implications for precious metal distribution in felsic magmatic-hydrothermal systems

    NASA Astrophysics Data System (ADS)

    Hanley, J. J.; MacKenzie, M. K.

    2009-05-01

    Certain alkalic porphyry Cu-Au systems contain significant concentrations of the platinum-group elements (PGE) Pd and Pt, and may serve as important unconventional resources for these metals. Bulk rock analyses of ore styles from these deposits show no correlation between the PGE and Cu-Au abundance, suggesting that the timing/mechanisms of introduction and precipitation for the PGE and Cu-Au were not the same. To elucidate some uncertainties concerning PGE enrichment, we have performed a mineralogical evaluation of two PGE-bearing porphyry systems in British Columbia (the Afton and Mount Milligan deposits) with the aid of a variety of microanalytical techniques (LA-ICPMS, SEM, EMP). Discrete PGE mineralogy in these systems is predominantly represented by Hg-rich Pd-Pt-As-Sb species (naldrettite-stibiopalladinite-sperrylite) and Pd-Te-Hg species (kotulskite-temagamite). However, these mineral phases are unambiguously late- stage (with carbonate-chlorite alteration) and contribute insignificantly (<5-10%) to the total Pd+Pt grade based on mass balance calculations. Similarly, LA-ICPMS analyses of chalcopyrite, bornite, oxides and various common sulfosalts show that these do not contribute any Pd+Pt to the bulk grades. Suprisingly, pyrite is the predominant carrier of PGE. It occurs in trace to minor abundances and predates both the Cu-Au mineralising event and the late stage carbonate-chlorite alteration. LA-ICPMS analyses of pyrite show that at least 90% of the bulk Pd+Pt occurs within this atypical host mineral. The PGE are highly enriched in the cores of the pyrite grains (up to 90 ppm and 20 ppm, respectively) and their abundance correlates well with Co (up to 4 wt%). The rims of the pyrite grains are Co-PGE-poor but Ni-rich. Early Co- PGE enrichment in these deposits may implicate a mafic contributor to the PGE tenor of the deposits, but also a potential crystallographic (substitutional) control on Pd partitioning into pyrite. At Afton, the former is supported by LA-ICPMS analyses of primary silicate melt inclusions within leucititic, high Mg basalt flows that are coeval with the porphyry rocks. These glassy inclusions preserve Pd/Pt ratios that are of the same order of magnitude as the bulk mineralization, suggesting possibly a common parental melt source for these metals coupled with limited fractionation of Pd from Pt during melt fractionation or mixing, melt ascent, fluid exsolution, and pyrite precipitation. The results of this study show that minor pyrite is an important repository of PGE in alkalic (shoshonitic) Cu- Au porphyry deposits. PGE precipitation in pyrite was coincident to Co enrichment during a hydrothermal event that pre-dated Cu and Au precipitation. From the perspective of resource evaluation, this unusual association may lead to misrepresentation of PGE grades if analyses of only Cu concentrates are obtained. From the point of view of exploration, recognition of bulk Co anomalies will not be useful because pyrite is not the only mineral controlling Co abundance in the system (spinels, chalcopyrite, mafic silicates) and is present in abundances of only 2-5 vol%. On the other hand, recognition of Co-rich pyrites in heavy mineral separates or thin section (detectable by routine microprobe) may be a viable tool for discriminating between PGE-barren and PGE- bearing systems since it is only the Co-rich pyrite that is associated with Pd and Pt enrichment.

  17. Mineral resource of the month: rare earth elements

    USGS Publications Warehouse

    U.S. Geological Survey

    2011-01-01

    The article provides information on rare earth elements, which are group of 17 natural metallic elements. The rare earth elements are scandium, yttrium and lanthanides and classified into light rare earth elements (LREE) and heavy rate earth elements (HREE). The principal ores of the rare earth elements are identified. An overview of China's production of 97 percent of the rare earths in the world is provided. Commercial applications of rare earths are described.

  18. Planets Around Low-mass Stars (PALMS). V. Age-dating Low-mass Companions to Members and Interlopers of Young Moving Groups

    NASA Astrophysics Data System (ADS)

    Bowler, Brendan P.; Shkolnik, Evgenya L.; Liu, Michael C.; Schlieder, Joshua E.; Mann, Andrew W.; Dupuy, Trent J.; Hinkley, Sasha; Crepp, Justin R.; Johnson, John Asher; Howard, Andrew W.; Flagg, Laura; Weinberger, Alycia J.; Aller, Kimberly M.; Allers, Katelyn N.; Best, William M. J.; Kotson, Michael C.; Montet, Benjamin T.; Herczeg, Gregory J.; Baranec, Christoph; Riddle, Reed; Law, Nicholas M.; Nielsen, Eric L.; Wahhaj, Zahed; Biller, Beth A.; Hayward, Thomas L.

    2015-06-01

    We present optical and near-infrared adaptive optics (AO) imaging and spectroscopy of 13 ultracool (>M6) companions to late-type stars (K7-M4.5), most of which have recently been identified as candidate members of nearby young moving groups (YMGs; 8-120 Myr) in the literature. Three of these are new companions identified in our AO imaging survey, and two others are confirmed to be comoving with their host stars for the first time. The inferred masses of the companions (˜10-100 MJup) are highly sensitive to the ages of the primary stars; therefore we critically examine the kinematic and spectroscopic properties of each system to distinguish bona fide YMG members from old field interlopers. The new M7 substellar companion 2MASS J02155892-0929121 C (40-60 MJup) shows clear spectroscopic signs of low gravity and, hence, youth. The primary, possibly a member of the ˜40 Myr Tuc-Hor moving group, is visually resolved into three components, making it a young low-mass quadruple system in a compact (?100 AU) configuration. In addition, Li i ?6708 absorption in the intermediate-gravity M7.5 companion 2MASS J15594729+4403595 B provides unambiguous evidence that it is young (?200 Myr) and resides below the hydrogen-burning limit. Three new close-separation (<1?) companions (2MASS J06475229-2523304 B, PYC J11519+0731 B, and GJ 4378 Ab) orbit stars previously reported as candidate YMG members, but instead are likely old (?1 Gyr) tidally locked spectroscopic binaries without convincing kinematic associations with any known moving group. The high rate of false positives in the form of old active stars with YMG-like kinematics underscores the importance of radial velocity and parallax measurements to validate candidate young stars identified via proper motion and activity selection alone. Finally, we spectroscopically confirm the cool temperature and substellar nature of HD 23514 B, a recently discovered M8 benchmark brown dwarf orbiting the dustiest-known member of the Pleiades. Based on observations collected at the European Organization for Astronomical Research in the Southern Hemisphere, Chile (ESO Program 090.A-9010(A)).

  19. Advances in optical design and optimization of miniature zoom optics with liquid lens element

    NASA Astrophysics Data System (ADS)

    Tsai, Cheng-Mu; Fang, Yi-Chin

    2012-11-01

    An optical design of 2X optical miniature zoom lens with liquid lens elements and optimization method: discrete lens groups shifts (DLGS) has been presented in this research. Two liquid elements are applied to minimize the overall length of zoom optics. Moreover, a compensative optimization method with assistance of Genetic Algorism is introduced in this research with a new concept of DLGS, which not only solve the complicated problem of liquid optics itself but also improve the performance of optics. Genetic algorithms (GA) written in CODE V plays the role at finding out the appropriate parameters such as curvatures, thicknesses, glass materials and etc. Besides, one table with great lens groups shifts by GA would be created to move the lens groups on the optimal positions of different zooms. As a result, the DLGS optimization method associated with the GA optimization improve the zoom lens performance averagely 40% better than traditional ones.

  20. Group Counseling

    ERIC Educational Resources Information Center

    Mahler, Clarence A.

    1971-01-01

    This article reviews the major concerns of group counseling and differentiates among group guidance, group counseling, and group therapy. It also evaluates the research status of group counseling and presents implications for the future of this approach. Comment by Carl E. Thoresen follows. (Author)

  1. Elements Involved in Academic Change.

    ERIC Educational Resources Information Center

    Walker, Charles U., Ed.

    The present document presents 3 papers that were prepared for an invitational conference on the Dynamics of Academic Change. The purpose of the conference was to develop an awareness of elements involved in bringing about academic change. The plan was for small groups of faculty and administrators to study sociological, psychological, and…

  2. Rutile crystals as potential trace element and isotope mineral standards for microanalysis

    E-print Network

    reports trace element concentrations of 15 elements (V, Cr, Fe, Zr, Nb, Mo, Sn, Sb, Hf, Ta, W, Lu, Pb, Th in the core of two of the studied grains. The trace element concentrations of the grains span a broad

  3. Application of Heisenberg's S matrix program to the angular scattering of the H + D2(v(i) = 0, j(i) = 0) ? HD(v(f) = 3, j(f) = 0) + D reaction: piecewise S matrix elements using linear, quadratic, step-function, and top-hat parametrizations.

    PubMed

    Shan, Xiao; Connor, J N L

    2012-11-26

    A previous paper by Shan and Connor (Phys. Chem. Chem. Phys. 2011, 13, 8392) reported the surprising result that four simple parametrized S matrices can reproduce the forward-angle glory scattering of the H + D(2)(v(i)=0,j(i)=0) ? HD(v(f)=3,j(f)=0) + D reaction, whose differential cross section (DCS) had been computed in a state-of-the-art scattering calculation for a state-of-the-art potential energy surface. Here, v and j are vibrational and rotational quantum numbers, respectively, and the translational energy is 1.81 eV. This paper asks the question: Can we replace the analytic functions (of class C(?)) used by Shan-Connor with simpler mathematical functions and still reproduce the forward-angle glory scattering? We first construct S matrix elements (of class C(0)) using a quadratic phase and a piecewise-continuous pre-exponential factor consisting of three pieces. Two of the pieces are constants, with one taking the value N (a real normalization constant) at small values of the total angular momentum number, J; the other piece has the value 0 at large J. These two pieces are joined at intermediate values of J by either a straight line, giving rise to the linear parametrization (denoted param L), or a quadratic curve, which defines the quadratic parametrization (param Q). We find that both param L and param Q can reproduce the glory scattering for center-of-mass reactive scattering angles, ?(R) ? 30°. Second, we use a piecewise-discontinuous pre-exponential factor and a quadratic phase, giving rise to a step-function parametrization (param SF) and a top-hat parametrization (param TH). We find that both param SF and param TH can reproduce the forward-angle scattering, even though these class C(-1) parametrizations are usually considered too simplistic to be useful for calculations of DCSs. We find that an ultrasimplistic param THz, which is param TH with a phase of zero, can also reproduce the glory scattering at forward angles. The S matrix elements for param THz are real and consist of five nonzero equal values, given by S(J) = 0.02266, for the window, J = 21(1)25. Param THz is sufficiently simple that we can derive closed forms for the partial wave scattering amplitude, f(?(R)), and the near-side (N) and far-side (F) subamplitudes. We show that window representations of f(?(R)) provide important insights into the range of J values that contribute to the reaction dynamics. Other theoretical techniques used are NF theory for the analysis of DCSs and full and NF local angular momentum theory, in both cases including up to three resummations of f(?(R)) before making the NF decomposition. Finally, we investigate the accuracy of various semiclassical glory theories for the DCS of param L. By varying one phase parameter for param L, we show that the uniform semiclassical approximation is accurate from ?(R) = 0° to close to ?(R) = 180°. Our approach is an example of a "weak" form of Heisenberg's S matrix program, which does not use a potential energy surface(s); rather it focuses on the properties of the S matrix. Our method is easy to apply to DCSs from experimental measurements or from computer simulations. PMID:22876759

  4. Adaptive electrowetting lens-prism element.

    PubMed

    Terrab, Soraya; Watson, Alexander M; Roath, Christopher; Gopinath, Juliet T; Bright, Victor M

    2015-10-01

    An adaptive electrowetting-based element with focusing and steering capability has been demonstrated in a monolithic design. Curvature and tip-tilt variation have been demonstrated using low voltages. A steering range of up to 4.3° and lens tuning of 18 diopters have been measured at 30 V DC and 21 V DC, respectively. PMID:26480097

  5. Probing the Role of a Secondary Structure Element at the 5-and 3-Splice Sites in Group I Intron Self-Splicing: The Tetrahymena L-16 ScaI Ribozyme Reveals a

    E-print Network

    Herschlag, Dan

    Self-Splicing: The Tetrahymena L-16 ScaI Ribozyme Reveals a New Role of the G,U Pair in Self of the group I self-splicing reaction. The Tetrahymena L-21 ScaI ribozyme, the best studied of these intron-splicing and release of the ligated exons after the second step of self-splicing. The group I intron from Tetrahymena

  6. I. Novel methods to gallium nitride heterostructures via UHV-CVD and azidogallanes. II. Synthesis of related group IV and V covalent systems

    NASA Astrophysics Data System (ADS)

    McMurran, Jeffrey Allen

    1998-12-01

    The synthesis of new, potentially practical materials through novel molecular chemistry and ultrahigh vacuum chemical vapor deposition (UHV-CVD) is described. The method involves the synthesis of carefully designed, single-source inorganic precursors that incorporate the desired structure and/or stoichiometry of the target material. The nature of the precursors, no C--H or N--H bonds, and labile leaving groups, affords uncommonly low deposition temperatures. The family of azidogallanes of the formula HnX2-nGaN 3 (X = Cl, Br; n = 1-2) have been prepared and identified by spectroscopic methods. C12GaN3 has been used to deposit heteroeptaxial GaN on sapphire at 700°C and high quality wurtzite material on Si. This is the first example of an entirely inorganic single-source precursor used to produce nitride material at 500--700°C with growth rates of 5--40nm/min. [HCIGaN3]4, the first example of a group 13 metal cyclooctane-like structure with bridging azide ligands, has been prepared. Film growth at 500--700°C producing columnar wurtzite GaN and room temperature decomposition to yield mixed-phase (wurtzite/zinc blende) nanocrystalline GaN fibrous material is demonstrated. (D2)H2GaN3 is prepared in high yield and purity by the reduction of Br2GaN3 with LiGaH 4. This molecule affords the simplest chemical route to GaN material decomposing via elimination of H2 and N2 to yield stoichiometric GaN material at uncommonly low temperatures of 200--800°C. This compound and its deuterium analog is readily distilled at reduced pressure (0.20 Torr, 40°C), and is remarkably stable under vacuum or inert atmosphere for extended periods (weeks). Germylene insertion chemistry has been used to produce the compound (GeBr3)3CH by complete insertion reaction of HCBr 3 (bromoform) and GeBr2.dioxane at 85% yield. The molecule is identified by chemical analysis, spectroscopic properties and mass spectrum. The corresponding hydrde (GeH3)3CH, is prepared by reduction of the bromide with LiAIH4 in 15--20% yield, and is identified with spectroscopic analysis and gas phase electron diffraction. A gas phase electron diffraction analysis is also presented for the related (GeH3)4C. Reactions of SiH4 with (SiH2CI)4C at 625--740°C produce Si-C alloys of composition Si1-yCy with carbon concentrations from 5--20%. Infrared analysis, Rutherford backscattering, and electron microscopy, confirm the composition and reveal a lack of the stable beta-SiC phase. Reactions of (SiH2Cl)4C with excess ammonia produce novel Si-C-N films of composition Si4CN4 at temperatures from 625--750°C. Rutherford backscattering confirms the stoichiometry of the material and reveals a lack of Cl and, 0 impurities. Microindentation experiments of the Si--C and Si--C--N films yield hardness slightly greater than pure Si for Si--C, and intermediate to Si3N4 and SiC for Si--C--N respectively.

  7. M-shell ionization of heavy elements by 0.1-1.0 MeV/amu {sup 1,2}H and {sup 3,4}He ions

    SciTech Connect

    Pajek, M.; Banas, D.; Braziewicz, J.; Czarnota, M.; Bienkowski, A.; Jaskola, M.; Korman, A.; Trautmann, D.; Lapicki, G.

    2006-01-15

    The M-shell ionization in high-Z atoms by low-energy light {sub 1}{sup 1}H, {sub 1}{sup 2}H, {sub 2}{sup 3}He, and {sub 2}{sup 4}He ions have been studied systematically in the energy range 0.1-1.0 MeV/amu in order to verify the available theoretical approaches describing the M-shell ionization by charged particles in asymmetric collisions. The present low-energy data, combined with our earlier results reported for M-shell ionization by hydrogen and helium ions for higher energies, form a systematic experimental basis to test the theoretical predictions of M-shell ionization based on the plane-wave Born approximation (PWBA), the semiclassical approximation (SCA), and the binary-encounter approximation (BEA). In the PWBA based approaches the energy loss (E), Coulomb deflection (C), perturbed stationary state (PSS), and relativistic (R) effects were considered within the ECPSSR theory and its recent modification, called the ECUSAR theory, in which a description of the PSS effect was corrected to account for the united- and separated-atom (USA) electron binding energy limits. In the SCA calculations with relativistic wave functions the binding effect was included only in the limiting cases of separated-atom and united-atom limits. Possible contribution of the electron capture, multiple ionization, and recoil ionization to the M-shell vacancy production, which is dominated for light ions impact by direct single ionization process, are also discussed. The universal scaling of measured M-shell x-ray production and ionization cross sections was investigated in detail. Using the present data the isotopic effect has been studied by comparing the measured M-shell ionization cross-section ratios for equal-velocity hydrogen {sub 1}{sup 1}H and {sub 1}{sup 2}H as well as helium {sub 2}{sup 3}He and {sub 2}{sup 4}He isotopes. In addition, the ratios of measured ionization cross sections for {sub 1}{sup 2}H and {sub 2}{sup 4}He were used to investigate the role of the binding effect. The present results are of practical importance for the application of particle-induced x-ray emission technique in trace element studies.

  8. Trace element indiscrimination diagrams

    NASA Astrophysics Data System (ADS)

    Li, Chusi; Arndt, Nicholas T.; Tang, Qingyan; Ripley, Edward M.

    2015-09-01

    We tested the accuracy of trace element discrimination diagrams for basalts using new datasets from two petrological databases, PetDB and GEOROC. Both binary and ternary diagrams using Zr, Ti, V, Y, Th, Hf, Nb, Ta, Sm, and Sc do a poor job of discriminating between basalts generated in various tectonic environments (continental flood basalt, mid-ocean ridge basalt, ocean island basalt, oceanic plateau basalt, back-arc basin basalt, and various types of arc basalt). The overlaps between the different types of basalt are too large for the confident application of such diagrams when used in the absence of geological and petrological constraints. None of the diagrams we tested can clearly discriminate between back-arc basin basalt and mid-ocean ridge basalt, between continental flood basalt and oceanic plateau basalt, and between different types of arc basalt (intra-oceanic, island and continental arcs). Only ocean island basalt and some mid-ocean ridge basalt are generally distinguishable in the diagrams, and even in this case, mantle-normalized trace element patterns offer a better solution for discriminating between the two types of basalt.

  9. Seed Laser Chirping for Enhanced Backward Raman Amplification in Plasmas Z. Toroker, V. M. Malkin, and N. J. Fisch

    E-print Network

    Seed Laser Chirping for Enhanced Backward Raman Amplification in Plasmas Z. Toroker, V. M. Malkin is that, by chirping the seed pulse, the group velocity dispersion may in fact be used advantageously elements will likely have to be replaced by plasma. In a plasma, a short counter-propagating seed pulse

  10. On Finite Groups and Finite Fields.

    ERIC Educational Resources Information Center

    Reid, J. D.

    1991-01-01

    Given a multiplicative group of nonzero elements with order n, the explicit relationship between the number of cyclic subgroups of order d, which divides n, is used in the proof concerning the cyclic nature of that given multiplicative group. (JJK)

  11. Special fiber elements for thermal analysis

    E-print Network

    Qin, Qinghua

    of this paper is to present a new special element model for thermal analysis of composites. Design/methodology algorithm for evaluating effective properties with special elements is presented. Keywords Programming-Aided Engineering and Software Vol. 28 No. 8, 2011 pp. 1079-1097 q Emerald Group Publishing Limited 0264-4401 DOI 10

  12. Modeling and Driving Piezoelectric Resonant Blade Elements

    E-print Network

    and in particular to the group that utilize the piezoelectric effect to generate motion such as motors and actuatorsModeling and Driving Piezoelectric Resonant Blade Elements Sam Ben-Yaakov* and Natan Krihely Power@ee.bgu.ac.il ; Website: http://www.ee.bgu.ac.il/~pel Abstract-- Piezoelectric Resonant Blade elements (PRB) are useful

  13. Summary Report of Working Group 2: Computation

    SciTech Connect

    Stoltz, P. H.; Tsung, R. S.

    2009-01-22

    The working group on computation addressed three physics areas: (i) plasma-based accelerators (laser-driven and beam-driven), (ii) high gradient structure-based accelerators, and (iii) electron beam sources and transport [1]. Highlights of the talks in these areas included new models of breakdown on the microscopic scale, new three-dimensional multipacting calculations with both finite difference and finite element codes, and detailed comparisons of new electron gun models with standard models such as PARMELA. The group also addressed two areas of advances in computation: (i) new algorithms, including simulation in a Lorentz-boosted frame that can reduce computation time orders of magnitude, and (ii) new hardware architectures, like graphics processing units and Cell processors that promise dramatic increases in computing power. Highlights of the talks in these areas included results from the first large-scale parallel finite element particle-in-cell code (PIC), many order-of-magnitude speedup of, and details of porting the VPIC code to the Roadrunner supercomputer. The working group featured two plenary talks, one by Brian Albright of Los Alamos National Laboratory on the performance of the VPIC code on the Roadrunner supercomputer, and one by David Bruhwiler of Tech-X Corporation on recent advances in computation for advanced accelerators. Highlights of the talk by Albright included the first one trillion particle simulations, a sustained performance of 0.3 petaflops, and an eight times speedup of science calculations, including back-scatter in laser-plasma interaction. Highlights of the talk by Bruhwiler included simulations of 10 GeV accelerator laser wakefield stages including external injection, new developments in electromagnetic simulations of electron guns using finite difference and finite element approaches.

  14. Optional elements and variant structures in the productions of bei2 'to give' dative constructions in Cantonese-speaking adults and three-year-old children.

    PubMed

    Wong, Anita M-Y; Chow, Dorcas C-C; McBride-Cheng, Catherine; Stokes, Stephanie F

    2010-01-01

    To express object transfer, Cantonese-speakers use a 'ditransitive' ([V-R-T] or [V-T-R] where V=Verb, T=Theme, R=Recipient), or a more complex prepositional/serial-verb (P/SV) construction. Clausal elements in Cantonese datives can be optional (resulting in 'full' versus 'non-full' forms) or appear in variant orders (full non-canonical and full canonical). We report on usage of dative constructions with the word bei2 'to give' in 86 parents and 53 three-year-old children during conversations. The parents used more P/SV than ditransitive bei2-datives, and vice versa for the children. Both groups showed a similar usage pattern of optional elements and variant structures in their ditransitive and P/SV bei2-datives. The roles of multiple construction types, optional elements and variant structures in children's learning of bei2-dative constructions are described. PMID:19272209

  15. The rulB gene of plasmid pWW0 is a hotspot for the site-specific insertion of integron-like elements found in the chromosomes of environmental Pseudomonas fluorescens group bacteria

    PubMed Central

    Rhodes, Glenn; Bosma, Hester; Studholme, David; Arnold, Dawn L; Jackson, Robert W; Pickup, Roger W

    2014-01-01

    The rulAB operon of Pseudomonas spp. confers fitness traits on the host and has been suggested to be a hotspot for insertion of mobile elements that carry avirulence genes. Here, for the first time, we show that rulB on plasmid pWW0 is a hotspot for the active site-specific integration of related integron-like elements (ILEs) found in six environmental pseudomonads (strains FH1–FH6). Integration into rulB on pWW0 occurred at position 6488 generating a 3 bp direct repeat. ILEs from FH1 and FH5 were 9403 bp in length and contained eight open reading frames (ORFs), while the ILE from FH4 was 16 233 bp in length and contained 16 ORFs. In all three ILEs, the first 5.1 kb (containing ORFs 1–4) were structurally conserved and contained three predicted site-specific recombinases/integrases and a tetR homologue. Downstream of these resided ORFs of the ‘variable side’ with structural and sequence similarity to those encoding survival traits on the fitness enhancing plasmid pGRT1 (ILEFH1 and ILEFH5) and the NR-II virulence region of genomic island PAGI-5 (ILEFH4). Collectively, these ILEs share features with the previously described type III protein secretion system effector ILEs and are considered important to host survival and transfer of fitness enhancing and (a)virulence genes between bacteria. PMID:24286439

  16. Rolling-Element Bearings

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.; Anderson, W. J.

    1983-01-01

    Rolling element bearings are a precision, yet simple, machine element of great utility. A brief history of rolling element bearings is reviewed and the type of rolling element bearings, their geometry and kinematics, as well as the materials they are made from and the manufacturing processes they involve are described. Unloaded and unlubricated rolling element bearings, loaded but unlubricated rolling element bearings and loaded and lubricated rolling element bearings are considered. The recognition and understanding of elastohydrodynamic lubrication covered, represents one of the major development in rolling element bearings.

  17. Group X

    SciTech Connect

    Fields, Susannah

    2007-08-16

    This project is currently under contract for research through the Department of Homeland Security until 2011. The group I was responsible for studying has to remain confidential so as not to affect the current project. All dates, reference links and authors, and other distinguishing characteristics of the original group have been removed from this report. All references to the name of this group or the individual splinter groups has been changed to 'Group X'. I have been collecting texts from a variety of sources intended for the use of recruiting and radicalizing members for Group X splinter groups for the purpose of researching the motivation and intent of leaders of those groups and their influence over the likelihood of group radicalization. This work included visiting many Group X websites to find information on splinter group leaders and finding their statements to new and old members. This proved difficult because the splinter groups of Group X are united in beliefs, but differ in public opinion. They are eager to tear each other down, prove their superiority, and yet remain anonymous. After a few weeks of intense searching, a list of eight recruiting texts and eight radicalizing texts from a variety of Group X leaders were compiled.

  18. Order computations in generic groups

    E-print Network

    Sutherland, Andrew V

    2007-01-01

    We consider the problem of computing the order of an element in a generic group. The two standard algorithms, Pollard's rho method and Shanks' baby-steps giant-steps technique, both use [theta](N^1/2) group operations to ...

  19. Groups as Categories Jeff Morton

    E-print Network

    Baez, John

    ). We are using the "non-evil" convention on composition order. 1 #12;such a natural transformation of the "underlying" groups), any natural transformation : F F consists of, for each object in the category G (of of a morphism in H as a category, or in other words, an element of the group H. This should make the naturality

  20. Discrete Element Modeling

    SciTech Connect

    Morris, J; Johnson, S

    2007-12-03

    The Distinct Element Method (also frequently referred to as the Discrete Element Method) (DEM) is a Lagrangian numerical technique where the computational domain consists of discrete solid elements which interact via compliant contacts. This can be contrasted with Finite Element Methods where the computational domain is assumed to represent a continuum (although many modern implementations of the FEM can accommodate some Distinct Element capabilities). Often the terms Discrete Element Method and Distinct Element Method are used interchangeably in the literature, although Cundall and Hart (1992) suggested that Discrete Element Methods should be a more inclusive term covering Distinct Element Methods, Displacement Discontinuity Analysis and Modal Methods. In this work, DEM specifically refers to the Distinct Element Method, where the discrete elements interact via compliant contacts, in contrast with Displacement Discontinuity Analysis where the contacts are rigid and all compliance is taken up by the adjacent intact material.

  1. arXiv:astroph/0109194 Galactic Cosmochronometry from Radioactive Elements

    E-print Network

    Cowan, John

    arXiv:astro­ph/0109194 v1 12 Sep 2001 { 1 { Galactic Cosmochronometry from Radioactive Elements of neutron-capture elemental abundances in Galactic halo stars, em- phasis is placed on the use of these elements to estimate the age of the Galactic halo. Two prominent characteristics of neutron

  2. Mobile elements and mammalian genome evolution Prescott L Deininger

    E-print Network

    Feschotte, Cedric

    Mobile elements and mammalian genome evolution Prescott L Deiningerà , John V Morany , Mark A Batzerz and Haig H Kazazian Jr§ Mobile elements make up large portions of most eukaryotic genomes and the development of innovative new assays to test the function of mobile elements have increased our understanding

  3. Food Groups

    MedlinePLUS

    ... About the Protein Foods Group Nutrients and Health Benefits Vegetarian Choices Tips for Making Wise Choices Food Gallery Dairy All About the Dairy Group Nutrients and Health Benefits Non-Dairy Sources of Calcium Tips to Making ...

  4. Theoretical predictions of properties and volatility of chlorides and oxychlorides of group-4 elements. II. Adsorption of tetrachlorides and oxydichlorides of Zr, Hf, and Rf on neutral and modified surfaces

    NASA Astrophysics Data System (ADS)

    Pershina, V.; Borschevsky, A.; Iliaš, M.; Türler, A.

    2014-08-01

    With the aim to interpret results of gas-phase chromatography experiments on volatility of group-4 tetrachlorides and oxychlorides including those of Rf, adsorption enthalpies of these species on neutral, and modified quartz surfaces were estimated on the basis of relativistic, two-component Density Functional Theory calculations of MCl4, MOCl2, MCl6-, and MOCl42 with the use of adsorption models. Several mechanisms of adsorption were considered. In the case of physisorption of MCl4, the trend in the adsorption energy in the group should be Zr > Hf > Rf, so that the volatility should change in the opposite direction. The latter trend complies with the one in the sublimation enthalpies, ?Hsub, of the Zr and Hf tetrachlorides, i.e., Zr < Hf. On the basis of a correlation between these quantities, ?Hsub(RfCl4) was predicted as 104.2 kJ/mol. The energy of physisorption of MOCl2 on quartz should increase in the group, Zr < Hf < Rf, as defined by increasing dipole moments of these molecules along the series. In the case of adsorption of MCl4 on quartz by chemical forces, formation of the MOCl2 or MOCl42- complexes on the surface can take place, so that the sequence in the adsorption energy should be Zr > Hf > Rf, as defined by the complex formation energies. In the case of adsorption of MCl4 on a chlorinated quartz surface, formation of the MCl62- surface complexes can occur, so that the trend in the adsorption strength should be Zr ? Hf < Rf. All the predicted sequences, showing a smooth change of the adsorption energy in the group, are in disagreement with the reversed trend Zr ? Rf < Hf, observed in the "one-atom-at-a-time" gas-phase chromatography experiments. Thus, currently no theoretical explanation can be found for the experimental observations.

  5. Correlation of trace elements in hair of patients with colon cancer

    NASA Astrophysics Data System (ADS)

    Kwiatek, W. M.; Cholewa, M.; Kajfosz, J.; Jones, K. W.; Shore, R. E.; Redrick, A. L.

    1987-03-01

    The trace element content of 116 hair samples from patients with colon cancer and from referent series of patients who had a variety of other diseases were measured using proton-induced X-ray emission (PIXE). The patients had been on largely uncontrolled diets, and the interest was whether there were differences in trace element concentrations attributable to the effects of colon cancer. The concentrations of K, Ca, Mn, Fe, Cu, Zn, Se, Br, and Rb were determined using a beam of 2.5-MeV protons. Minimum detectable limits (MDL) of 0.3 ppm were obtained for Zn and Se. Cluster analysis of the data set did not reveal any significant differences between the cancer and control groups. Mean values and ranges obtained for the elemental concentrations show good agreement with other published determinations.

  6. Micro-PIXE analysis of trace element concentrations of natural rubies from different locations in Myanmar

    NASA Astrophysics Data System (ADS)

    Sanchez, J. L.; Osipowicz, T.; Tang, S. M.; Tay, T. S.; Win, T. T.

    1997-07-01

    The trace element concentrations found in geological samples can shed light on the formation process. In the case of gemstones, which might be of artificial or natural origin, there is also considerable interest in the development of methods that provide identification of the origin of a sample. For rubies, trace element concentrations present in natural samples were shown previously to be significant indicators of the region of origin [S.M. Tang et al., Appl. Spectr. 42 (1988) 44, and 43 (1989) 219]. Here we report the results of micro-PIXE analyses of trace element (Ti, V, Cr, Fe, Cu and Ga) concentrations of a large set ( n = 130) of natural rough rubies from nine locations in Myanmar (Burma). The resulting concentrations are subjected to statistical analysis. Six of the nine groups form clusters when the data base is evaluated using tree clustering and principal component analysis.

  7. Dissolved trace element biogeochemistry of a tropical river, Southwestern India.

    PubMed

    Tripti, M; Gurumurthy, G P; Balakrishna, K; Chadaga, M D

    2013-06-01

    River Swarna, a small tropical river originating in Western Ghats (at an altitude of 1,160 m above mean sea level) and flowing in the southwest coast of India discharges an average of 54 m(3)s(-1) of water into the Arabian Sea, of which significant part is being discharged during the monsoon. No studies have been made yet on the water chemistry of the Swarna River basin, even as half a million people of Udupi district use it for domestic and irrigational purposes. As large community in this region depends on the freshwater of Swarna River, there is an urgent need to study the trace element geochemistry of this west flowing river for better water management and sustainable development. The paper presents the results on the biogeochemistry of dissolved trace elements in the Swarna River for a period of 1 year. The results obtained on the trace elements show seasonal effect on the concentrations as well as behavior and thus forming two groups, discharge driven (Li, Be, Al, V, Cr, Ni, Zr, In, Pb, Bi and U) and base flow driven (groundwater input; Mn, Fe, Co, Cu, Ga, Zn, As, Se, Rb, Sr, Ag, Cd, Cs, Ba and Tl) trace elements in Swarna River. The biogeochemical processes explained through Hierarchical Cluster Analysis show complexation of Fe, Ga and Ba with dissolved organic carbon, redox control over Mn and Tl and biological control over V and Ni. Also, the water quality of Swarna River remains within the permissible limits of drinking water standards. PMID:23224502

  8. Normed ?-Group

    E-print Network

    Aleks Kleyn

    2013-10-17

    Since sum which is not necessarily commutative is defined in \\Omega-algebra A, then \\Omega-algebra A is called \\Omega-group. I also considered representation of \\Omega-group. Norm defined in \\Omega-group allows us to consider continuity of operations and continuity of representation.

  9. Contribution to the geochemistry of trace elements in the sediments of the Noun River and tributaries, western Cameroon.

    PubMed

    Njofang, C; Matschullat, J; Tchouankoué, J P; Amougou, A

    2007-09-15

    This study reports on the distribution of trace elements in the sediments of the Noun River valley. Two groups of trace elements have emerged based on their distribution and geochemical behaviour. The first group shows lower values whereas the second group aligns higher values. Elements like Al and Sr in one side and Zn, Zr in the other present concentrations statistically different from those of the rocks compared to other elements in trace analyzed (Cr, Ni, Ba, Co, Cu, Fe, Mn, V, As and Pb). The trace elements Al, Sr, Zr, Zn and Pb in the sediments of the Noun River show concentrations rather lower than those of the world. The average concentrations in elements C (3.72%), N (0.27%), S (0.05%) and of the ratios C/N (13.77) and N/S (5.29) reflect those resulting from the decomposition of the organic matter which derives from soils with very small concentrations in S. The Noun valley sediments are mostly of primary (quartz, microcline, plagioclase, orthoclase, ilmenite, anatase) and newly formed or secondary (kaolinite, gibbsite, hematite, goethite) minerals. This mineralogy and the overall low concentration of the studied trace elements, with Al, Fe, Ti and Mn as most abundant elements, is consistent with the local geology made up of the basic rocks (basalts, volcanic ash) and of the acid rocks (granites, gneiss). Overall the trace elements concentration and distribution suggest their geogene origin. Yet, this study is a first contribution of its kind towards the development of a baseline geochemical database essential for a sustainable and healthier Noun valley ecosystem. PMID:19090098

  10. Organic Elemental Analysis.

    ERIC Educational Resources Information Center

    Ma, T. S.; Wang, C. Y.

    1984-01-01

    Presents a literature review on methods used to analyze organic elements. Topic areas include methods for: (1) analyzing carbon, hydrogen, and nitrogen; (2) analyzing oxygen, sulfur, and halogens; (3) analyzing other elements; (4) simultaneously determining several elements; and (5) determing trace elements. (JN)

  11. The Unfocused Focus Group: Benefit or Bane?

    ERIC Educational Resources Information Center

    Franz, Nancy K.

    2011-01-01

    Facilitating successful focus groups requires both science and art. One element that can fully challenge focus group facilitators includes how to handle the unfocused focus group. This article describes "unfocus" and the benefits and disadvantages of unfocus in focus groups. Lessons learned from and approaches taken on this journey are shared to…

  12. The Superheavy Elements and Anti-Gravity

    NASA Astrophysics Data System (ADS)

    Anastasovski, Petar K.

    2004-02-01

    The essence of any propulsion concept is to overcome gravity. Anti-gravity is a natural means to achieve this. Thus, the technology to pursue anti-gravity, by using superheavy elements, may provide a new propulsion paradigm. The theory of superluminal relativity provides a hypothesis for existence of elements with atomic number up to Z = 145, some of which may possess anti-gravity properties. Analysis results show that curved space-time exists demonstrating both gravitic and anti-gravitic properties not only around nuclei but inside the nuclei as well. Two groups of elements (Z < 64 and 63 < Z <145) exist that demonstrate these capabilities. The nuclei of the first group of elements have the masses with only the property of gravity. The nuclei of the elements of the second group have the masses with both properties: gravity and anti-gravity in two different ranges of curved space-time around the nuclei.. The hypothetical element with Z = 145 is the unique among all elements whose nucleus has only anti-gravity property. It is proposed that this element be named Hawking, in honour of Stephen W. Hawking.

  13. The Superheavy Elements and Anti-Gravity

    SciTech Connect

    Anastasovski, Petar K.

    2004-02-04

    The essence of any propulsion concept is to overcome gravity. Anti-gravity is a natural means to achieve this. Thus, the technology to pursue anti-gravity, by using superheavy elements, may provide a new propulsion paradigm. The theory of superluminal relativity provides a hypothesis for existence of elements with atomic number up to Z = 145, some of which may possess anti-gravity properties. Analysis results show that curved space-time exists demonstrating both gravitic and anti-gravitic properties not only around nuclei but inside the nuclei as well. Two groups of elements (Z < 64 and 63 < Z <145) exist that demonstrate these capabilities. The nuclei of the first group of elements have the masses with only the property of gravity. The nuclei of the elements of the second group have the masses with both properties: gravity and anti-gravity in two different ranges of curved space-time around the nuclei.. The hypothetical element with Z = 145 is the unique among all elements whose nucleus has only anti-gravity property. It is proposed that this element be named Hawking, in honour of Stephen W. Hawking.

  14. Distinguishing symmetric quantum oracles and quantum group multiplication

    E-print Network

    Orest Bucicovschi; Daniel Copeland; David A. Meyer; James Pommersheim

    2015-03-18

    Given a unitary representation of a finite group on a finite-dimensional Hilbert space, we show how to find a state whose translates under the group are distinguishable with the highest probability. We apply this to several quantum oracle problems, including the GROUP MULTIPLICATION problem, in which the product of an ordered $n$-tuple of group elements is to be determined by querying elements of the tuple. For any finite group $G$, we give an algorithm to find the product of two elements of $G$ with a single quantum query with probability $2/|G|$. This generalizes Deutsch's Algorithm from $Z_2$ to an arbitrary finite group. We further prove that this algorithm is optimal. We also introduce the HIDDEN CONJUGATING ELEMENT PROBLEM, in which the oracle acts by conjugating by an unknown element of the group. We show that for many groups, including dihedral and symmetric groups, the unknown element can be determined with probability $1$ using a single quantum query.

  15. TEST GROUPS FOR WHITEHEAD GROUPS PAUL C. EKLOF, LASZLO FUCHS, AND SAHARON SHELAH

    E-print Network

    Eklof, Paul C.

    if every W-group is free (for example in a model of V = L); therefore we will focus on models whereTEST GROUPS FOR WHITEHEAD GROUPS PAUL C. EKLOF, L´ASZL´O FUCHS, AND SAHARON SHELAH Abstract. We consider the question of when the dual of a Whitehead group is a test group for Whitehead groups

  16. Taxonomy Working Group Final Report

    NASA Technical Reports Server (NTRS)

    Parsons, Vickie S.; Beil, Robert J.; Terrone, Mark; Barth, Timothy S.; Panontin, Tina L.; Wales, Roxana; Rackley, Michael W.; Milne, James S.; McPherson, John W.; Dutra, Jayne E.; Shaw, Larry C.

    2009-01-01

    The purpose of the Taxonomy Working Group was to develop a proposal for a common taxonomy to be used by all NASA projects in the classifying of nonconformances, anomalies, and problems. Specifically, the group developed a recommended list of data elements along with general suggestions for the development of a problem reporting system to better serve NASA's need for managing, reporting, and trending project aberrant events. The Group's recommendations are reported in this document.

  17. Religious Groups v. TV's Sex, Violence.

    ERIC Educational Resources Information Center

    Schicht, Jack

    Religious organizations have played an important part in the national movement to combat sex and violence in television programing. Attempts by religious organizations to exercise some control of the visual media began in 1907 with a concern for movies and has continued to the present. Although many churches and church organizations have expressed…

  18. Chemical characterization of bohrium (element 107)

    PubMed

    Eichler; Bruchle; Dressler; Dullmann; Eichler; Gaggeler; Gregorich; Hoffman; Hubener; Jost; Kirbach; Laue; Lavanchy; Nitsche; Patin; Piguet; Schadel; Shaughnessy; Strellis; Taut; Tobler; Tsyganov; Turler; Vahle; Wilk; Yakushev

    2000-09-01

    The arrangement of the chemical elements in the periodic table highlights resemblances in chemical properties, which reflect the elements' electronic structure. For the heaviest elements, however, deviations in the periodicity of chemical properties are expected: electrons in orbitals with a high probability density near the nucleus are accelerated by the large nuclear charges to relativistic velocities, which increase their binding energies and cause orbital contraction. This leads to more efficient screening of the nuclear charge and corresponding destabilization of the outer d and f orbitals: it is these changes that can give rise to unexpected chemical properties. The synthesis of increasingly heavy elements, now including that of elements 114, 116 and 118, allows the investigation of this effect, provided sufficiently long-lived isotopes for chemical characterization are available. In the case of elements 104 and 105, for example, relativistic effects interrupt characteristic trends in the chemical properties of the elements constituting the corresponding columns of the periodic table, whereas element 106 behaves in accordance with the expected periodicity. Here we report the chemical separation and characterization of six atoms of element 107 (bohrium, Bh), in the form of its oxychloride. We find that this compound is less volatile than the oxychlorides of the lighter elements of group VII, thus confirming relativistic calculations that predict the behaviour of bohrium, like that of element 106, to coincide with that expected on the basis of its position in the periodic table. PMID:10993071

  19. Galaxy groups

    SciTech Connect

    Brent Tully, R.

    2015-02-01

    Galaxy groups can be characterized by the radius of decoupling from cosmic expansion, the radius of the caustic of second turnaround, and the velocity dispersion of galaxies within this latter radius. These parameters can be a challenge to measure, especially for small groups with few members. In this study, results are gathered pertaining to particularly well-studied groups over four decades in group mass. Scaling relations anticipated from theory are demonstrated and coefficients of the relationships are specified. There is an update of the relationship between light and mass for groups, confirming that groups with mass of a few times 10{sup 12}M{sub ?} are the most lit up while groups with more and less mass are darker. It is demonstrated that there is an interesting one-to-one correlation between the number of dwarf satellites in a group and the group mass. There is the suggestion that small variations in the slope of the luminosity function in groups are caused by the degree of depletion of intermediate luminosity systems rather than variations in the number per unit mass of dwarfs. Finally, returning to the characteristic radii of groups, the ratio of first to second turnaround depends on the dark matter and dark energy content of the universe and a crude estimate can be made from the current observations of ?{sub matter}?0.15 in a flat topology, with a 68% probability of being less than 0.44.

  20. Partitioning of platinum-group elements (PGE) and chalcogens (Se, Te, As, Sb, Bi) between monosulfide-solid solution (MSS), intermediate solid solution (ISS) and sulfide liquid at controlled fO2-fS2 conditions

    NASA Astrophysics Data System (ADS)

    Liu, Yanan; Brenan, James

    2015-06-01

    In order to better understand the behavior of highly siderophile elements (HSEs: Os, Ir, Ru, Rh, Pt, Pd, Au, Re), Ag, Pb and chalcogens (As, Se, Sb, Te and Bi) during the solidification of sulfide magmas, we have conducted a series of experiments to measure partition coefficients (D values) between monosulfide solid solution (MSS) and sulfide melt, as well as MSS and intermediate solid solution (ISS), at 0.1 MPa and 860-926 °C, log fS2 -3.0 to -2.2 (similar to the Pt-PtS buffer), with fO2 controlled at the fayalite-magnetite-quartz (FMQ) buffer. The IPGEs (Os, Ir, Ru), Rh and Re are found to be compatible in MSS relative to sulfide melt with D values ranging from ?20 to ?5, and DRe/DOs of ?0.5. Pd, Pt, Au, Ag, Pb, as well as the chalcogens, are incompatible in MSS, with D values ranging from ?0.1 to ?1 × 10-3. For the same metal/sulfur ratio, D values for the IPGEs, Rh and Re are systematically larger than most past studies, correlating with higher oxygen content in the sulfide liquid, reflecting the significant effect of oxygen on increasing the activity coefficients for these elements in the melt phase. MSS/ISS partitioning experiments reveal that Ru, Os, Ir, Rh and Re are partitioned into MSS by a factor of >50, whereas Pd, Pt, Ag, Au and the chalcogens partition from weakly (Se, As) to strongly (Ag, Au) into ISS. Uniformly low MSS- and ISS- melt partition coefficients for the chalcogens, Pt, Pd, Ag and Au will lead to enrichment in the residual sulfide liquid, but D values are generally too large to reach early saturation in Pt-Pd-chalcogen-rich accessory minerals, based on current solubility estimates. Instead, these phases likely precipitate at the last dregs of crystallization. Modeled evolution curves for the PGEs and chalcogens are in reasonably good agreement with whole-rock sulfide compositions for the McCreedy East deposit (Sudbury, Ontario), consistent with an origin by crystallization of MSS, then MSS + ISS from sulfide magma.

  1. Theoretical predictions of properties and volatility of chlorides and oxychlorides of group-4 elements. II. Adsorption of tetrachlorides and oxydichlorides of Zr, Hf, and Rf on neutral and modified surfaces

    SciTech Connect

    Pershina, V.; Borschevsky, A.; Iliaš, M.; Türler, A.

    2014-08-14

    With the aim to interpret results of gas-phase chromatography experiments on volatility of group-4 tetrachlorides and oxychlorides including those of Rf, adsorption enthalpies of these species on neutral, and modified quartz surfaces were estimated on the basis of relativistic, two-component Density Functional Theory calculations of MCl{sub 4}, MOCl{sub 2}, MCl{sub 6}{sup ?}, and MOCl{sub 4}{sup 2} with the use of adsorption models. Several mechanisms of adsorption were considered. In the case of physisorption of MCl{sub 4}, the trend in the adsorption energy in the group should be Zr > Hf > Rf, so that the volatility should change in the opposite direction. The latter trend complies with the one in the sublimation enthalpies, ?H{sub sub}, of the Zr and Hf tetrachlorides, i.e., Zr < Hf. On the basis of a correlation between these quantities, ?H{sub sub}(RfCl{sub 4}) was predicted as 104.2 kJ/mol. The energy of physisorption of MOCl{sub 2} on quartz should increase in the group, Zr < Hf < Rf, as defined by increasing dipole moments of these molecules along the series. In the case of adsorption of MCl{sub 4} on quartz by chemical forces, formation of the MOCl{sub 2} or MOCl{sub 4}{sup 2?} complexes on the surface can take place, so that the sequence in the adsorption energy should be Zr > Hf > Rf, as defined by the complex formation energies. In the case of adsorption of MCl{sub 4} on a chlorinated quartz surface, formation of the MCl{sub 6}{sup 2?} surface complexes can occur, so that the trend in the adsorption strength should be Zr ? Hf < Rf. All the predicted sequences, showing a smooth change of the adsorption energy in the group, are in disagreement with the reversed trend Zr ? Rf < Hf, observed in the “one-atom-at-a-time” gas-phase chromatography experiments. Thus, currently no theoretical explanation can be found for the experimental observations.

  2. Occurrence model for magmatic sulfide-rich nickel-copper-(platinum-group element) deposits related to mafic and ultramafic dike-sill complexes: Chapter I in Mineral deposit models for resource assessment

    USGS Publications Warehouse

    Schulz, Klaus J.; Woodruff, Laurel G.; Nicholson, Suzanne W.; Seal, Robert R., II; Piatak, Nadine M.; Chandler, Val W.; Mars, John L.

    2014-01-01

    The sulfides in magmatic Ni-Cu deposits generally constitute a small volume of the host rock(s) and tend to be concentrated in the lower parts of the mafic and/or ultramafic bodies, often in physical depressions or areas marking changes in the geometry of the footwall topography. In most deposits, the sulfide mineralization can be divided into disseminated, matrix or net, and massive sulfide, depending on a combination of the sulfide content of the rock and the silicate texture. The major Ni-Cu sulfide mineralogy typically consists of an intergrowth of pyrrhotite (Fe7S8), pentlandite ([Fe, Ni]9S8), and chalcopyrite (FeCuS2). Cobalt, PGE, and gold (Au) are extracted from most magmatic Ni-Cu ores as byproducts, although such elements can have a significant impact on the economics in some deposits, such as the Noril’sk-Talnakh deposits, which produce much of the world’s palladium. In addition, deposits may contain between 1 and 15 percent magnetite associated with the sulfides.

  3. Using laser micro mass spectrometry with the LAMMA-1000 instrument for monitoring relative elemental concentrations in vitrinite

    USGS Publications Warehouse

    Morelli, J.J.; Hercules, D.M.; Lyons, P.C.; Palmer, C.A.; Fletcher, J.D.

    1988-01-01

    The variation in relative elemental concentrations among a series of coal macerals belonging to the vitrinite maceral group was determined using laser micro mass spectrometry (LAMMS). Variations in Ba, Cr, Ga, Sr, Ti, and V concentrations among the coals were determined using the LAMM A-1000 instrument. LAMMS analysis is not limited to these elements; their selection illustrates the application of the technique. Ba, Cr, Ga, Sr, Ti, and V have minimal site-to-site variance in the vitrinite macerals of the studied coals as measured by LAMMS. The LAMMS data were compared with bulk elemental data obtained by instrumental neutron activation analysis (INAA) and D. C. arc optical emission spectroscopy (DCAS) in order to determine the reliability of the LAMMS data. The complex nature of the ionization phenomena in LAMMS and the lack of standards characterized on a microscale makes obtaining quantitative elemental data within the ionization microvolume difficult; however, we demonstrate that the relative variation of an element among vitrinites from different coal beds in the eastern United States can be observed using LAMMS in a "bulk" mode by accumulating signal intensities over several microareas of each vitrinite. Our studies indicate gross changes (greater than a factor of 2 to 5 depending on the element) can be monitored when the elemental concentration is significantly above the detection limit. "Bulk" mode analysis was conducted to evaluate the accuracy of future elemental LAMMS microanalyses. The primary advantage of LAMMS is the inherent spatial resolution, ~ 20 ??m for coal. Two different vitrite bands in the Lower Bakerstown coal bed (CLB-1) were analyzed. The analysis did not establish any certain concentration differences in Ba, Cr, Ga, Sr, Ti, and V between the two bands. ?? 1988 Springer-Verlag.

  4. GROUP INEQUALITY

    PubMed Central

    Bowles, Samuel; Loury, Glenn C.; Sethi, Rajiv

    2014-01-01

    We explore the combined effect of segregation in social networks, peer effects, and the relative size of a historically disadvantaged group on the incentives to invest in market-rewarded skills and the dynamics of inequality between social groups. We identify conditions under which group inequality will persist in the absence of differences in ability, credit constraints, or labor market discrimination. Under these conditions, group inequality may be amplified even if initial group differences are negligible. Increases in social integration may destabilize an unequal state and make group equality possible, but the distributional and human capital effects of this depend on the demographic composition of the population. When the size of the initially disadvantaged group is sufficiently small, integration can lower the long-run costs of human capital investment in both groups and result in an increase the aggregate skill share. In contrast, when the initially disadvantaged group is large, integration can induce a fall in the aggregate skill share as the costs of human capital investment rise in both groups. We consider applications to concrete cases and policy implications. PMID:25554727

  5. Bayesian hierarchical grouping: Perceptual grouping as mixture estimation.

    PubMed

    Froyen, Vicky; Feldman, Jacob; Singh, Manish

    2015-10-01

    We propose a novel framework for perceptual grouping based on the idea of mixture models, called Bayesian hierarchical grouping (BHG). In BHG, we assume that the configuration of image elements is generated by a mixture of distinct objects, each of which generates image elements according to some generative assumptions. Grouping, in this framework, means estimating the number and the parameters of the mixture components that generated the image, including estimating which image elements are "owned" by which objects. We present a tractable implementation of the framework, based on the hierarchical clustering approach of Heller and Ghahramani (2005). We illustrate it with examples drawn from a number of classical perceptual grouping problems, including dot clustering, contour integration, and part decomposition. Our approach yields an intuitive hierarchical representation of image elements, giving an explicit decomposition of the image into mixture components, along with estimates of the probability of various candidate decompositions. We show that BHG accounts well for a diverse range of empirical data drawn from the literature. Because BHG provides a principled quantification of the plausibility of grouping interpretations over a wide range of grouping problems, we argue that it provides an appealing unifying account of the elusive Gestalt notion of Prägnanz. (PsycINFO Database Record PMID:26322548

  6. Chalcophile and platinum-group element distribution in the Ultramafic series of the Stillwater Complex, MT, USA—implications for processes enriching chromite layers in Os, Ir, Ru, and Rh

    NASA Astrophysics Data System (ADS)

    Barnes, Sarah-Jane; Pagé, P.; Prichard, H. M.; Zientek, M. L.; Fisher, P. C.

    2015-05-01

    All of the rocks from the Ultramafic series of the Stillwater Complex are enriched in PGE relative to most mafic magmas. Furthermore, the chromite layers are particularly enriched in IPGE (Os, Ir, and Ru) and Rh. This enrichment appears to be a common characteristic of ultramafic rocks from many types of settings, layered intrusions, ophiolites, and zoned complexes. We have carried out a petrological, mineralogical, and geochemical study to assess how the enrichment occurred in the case of the Stillwater Complex and applied our results to the chromite layers of the Bushveld and Great Dyke complexes. The minerals that now host the PGE are laurite and fine-grained intergrowths of pentlandite, millerite, and chalcopyrite. The laurite occurs as inclusions in chromite, and mass balance calculations indicate that it hosts most of the Os, Ir, and Ru. The sulfide minerals occur both as inclusions in chromite and as interstitial grains. The sulfides host much of the Pd and Rh. The IPGE and Rh correlate with Cr but not with S or Se, indicating that these elements were not collected by a sulfide liquid. Palladium, Cu, and Se correlate with each other, but not with S. The low S/Se (<1500) of the whole rock and magnetite rims around the sulfides indicate some S has been lost from the rocks. We conclude that to account for all observations, the IPGE and Rh were originally collected by chromite, and subsequently, small quantities of base metal sulfide liquid was added to the chromite layers from the overlying magma. The IPGE and Rh in the chromite diffused from the chromite into the base metal sulfides and converted some of the sulfides to laurite.

  7. Inorganic element content of US coals: geographic variability and statistical evidence for modes of occurrence

    SciTech Connect

    Glick, D.C.; Davis, A.

    1985-01-01

    Environment of deposition and subsequent geologic history of a coal influence the concentrations and modes of occurrence of inorganic constituents at the sample site. In order to summarize the resulting variability and to understand modes of occurrence of trace elements by their association with better-known major elements, a statistical study using principal components analysis was performed. Three hundred thirty-five whole-seam channel samples from six US coal provinces were analyzed for nine major elements 17 trace elements, three S forms and high-temperature ash yield. Statistical analyses were performed on both whole-coal basis and ash-basis data sets. The study revealed that Cr, Ga, La, Rb, Sc, T, V and Y were statistically related to the elements Si, Al and K, which occur principally in aluminosilicates (clays). Be, Cu, Mn, Ni, U, Yb and Zn tended to associated with Fe and S (occurring in pyrite). Eastern province samples tended to have high values of the alumino-silicate-related elements and low values of Mg, Ca, Na, Mn and U on both bases, perhaps attributable to supply of detrital minerals during deposition. Interior province samples were relatively high in chalcophile elements and low in aluminosilicates on both bases; these coals were farther from detrital sources and may have been subjected to a greater marine influence. Gulf, Rocky Mountain, and Northern Great Plains province coals tended to be high in carbonate-related or organically-combined elements: some of these are low-rank coals, in which organic functional groups are important in holding inorganic elements.

  8. Origin of the Elements

    NASA Astrophysics Data System (ADS)

    Truran, J. W., Jr.; Heger, A.

    2003-12-01

    Nucleosynthesis is the study of the nuclear processes responsible for the formation of the elements which constitute the baryonic matter of the Universe. The elements of which the Universe is composed indeed have a quite complicated nucleosynthesis history, which extends from the first three minutes of the Big Bang through to the present. Contemporary nucleosynthesis theory associates the production of certain elements/isotopes or groups of elements with a number of specific astrophysical settings, the most significant of which are: (i) the cosmological Big Bang, (ii) stars, and (iii) supernovae.Cosmological nucleosynthesis studies predict that the conditions characterizing the Big Bang are consistent with the synthesis only of the lightest elements: 1H, 2H, 3He, 4He, and 7Li (Burles et al., 2001; Cyburt et al., 2002). These contributions define the primordial compositions both of galaxies and of the first stars formed therein. Within galaxies, stars and supernovae play the dominant role both in synthesizing the elements from carbon to uranium and in returning heavy-element-enriched matter to the interstellar gas from which new stars are formed. The mass fraction of our solar system (formed ˜4.6 Gyr ago) in the form of heavy elements is ˜1.8%, and stars formed today in our galaxy can be a factor 2 or 3 more enriched (Edvardsson et al., 1993). It is the processes of nucleosynthesis operating in stars and supernovae that we will review in this chapter. We will confine our attention to three broad categories of stellar and supernova site with which specific nucleosynthesis products are understood to be identified: (i) intermediate mass stars, (ii) massive stars and associated type II supernovae, and (iii) type Ia supernovae. The first two of these sites are the straightforward consequence of the evolution of single stars, while type Ia supernovae are understood to result from binary stellar evolution.Stellar nucleosynthesis resulting from the evolution of single stars is a strong function of stellar mass (Woosley et al., 2002). Following phases of hydrogen and helium burning, all stars consist of a carbon-oxygen core. In the mass range of the so-called "intermediate mass" stars (1<˜M/M?<˜10), the temperatures realized in their degenerate cores never reach levels at which carbon ignition can occur. Substantial element production occurs in such stars during the asymptotic giant branch (AGB) phase of evolution, accompanied by significant mass loss, and they evolve to white dwarfs of carbon-oxygen (or, less commonly, oxygen-neon) composition. In contrast, the increased pressures that are experienced in the cores of stars of masses M>˜10M? yield higher core temperatures that enable subsequent phases of carbon, neon, oxygen, and silicon burning to proceed. Collapse of an iron core devoid of further nuclear energy then gives rise to a type II supernova and the formation of a neutron star or black hole remnant (Heger et al., 2003). The ejecta of type IIs contain the ashes of nuclear burning of the entire life of the star, but are also modified by the explosion itself. They are the source of most material (by mass) heavier than helium.Observations reveal that binary stellar systems comprise roughly half of all stars in our galaxy. Single star evolution, as noted above, can leave in its wake compact stellar remnants: white dwarfs, neutron stars, and black holes. Indeed, we have evidence for the occurrence of all three types of condensed remnant in binaries. In close binary systems, mass transfer can take place from an evolving companion onto a compact object. This naturally gives rise to a variety of interesting phenomena: classical novae (involving hydrogen thermonuclear runaways in accreted shells on white dwarfs (Gehrz et al., 1998)), X-ray bursts (hydrogen/helium thermonuclear runaways on neutron stars (Strohmayer and Bildsten, 2003)), and X-ray binaries (accretion onto black holes). For some range of conditions, accretion onto carbon-oxygen white dwarfs will permit growth of the CO core to the Chan

  9. 7 CFR 29.6081 - Elements of quality and degrees of each element.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...value of each degree varies with type and group. Elements Degrees Body Heavy Medium Thin. Maturity Immature Mature Ripe. Leaf structure Close Firm Open. Elasticity Inelastic Semielastic Elastic. Strength...

  10. 7 CFR 29.6081 - Elements of quality and degrees of each element.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...value of each degree varies with type and group. Elements Degrees Body Heavy Medium Thin. Maturity Immature Mature Ripe. Leaf structure Close Firm Open. Elasticity Inelastic Semielastic Elastic. Strength...

  11. 7 CFR 29.3586 - Elements of quality and degrees of each element.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...the actual value of each degree varies with type, group, and grade. Elements Degrees Maturity Immature Underripe Mature Ripe. Body Thin Medium Heavy. Leaf structure Close Firm Open. Leaf surface Rough Crepy...

  12. 7 CFR 29.2601 - Elements of quality and degrees of each element.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...actual value of each degree varies with group. Elements Degrees Body Thin Medium Heavy. Maturity Immature Mature Ripe. Leaf structure Close Firm Open. Oil Lean Oily Rich. Elasticity Inelastic Semielastic...

  13. 7 CFR 29.2601 - Elements of quality and degrees of each element.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...actual value of each degree varies with group. Elements Degrees Body Thin Medium Heavy. Maturity Immature Mature Ripe. Leaf structure Close Firm Open. Oil Lean Oily Rich. Elasticity Inelastic Semielastic...

  14. 7 CFR 29.6081 - Elements of quality and degrees of each element.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...value of each degree varies with type and group. Elements Degrees Body Heavy Medium Thin. Maturity Immature Mature Ripe. Leaf structure Close Firm Open. Elasticity Inelastic Semielastic Elastic. Strength...

  15. Vesta's Elemental Composition

    NASA Technical Reports Server (NTRS)

    Prettyman, T. H.; Beck, A. W.; Feldman, W. C.; Lawrence, D. J.; McCoy, T. J.; McSween, H. Y.; Mittlefehldt, D. W.; Peplowski, P. N.; Raymond, C. A.; Reedy, R. C.; Russell, C. T.; Titus, T. N.; Toplis, M. J.; Yamashita, N.

    2014-01-01

    Many lines of evidence (e.g. common geochemistry, chronology, O-isotope trends, and the presence of different HED rock types in polymict breccias) indicate that the howardite, eucrite, and diogenite (HED) meteorites originated from a single parent body. Meteorite studies show that this protoplanet underwent igneous differentiation to form a metallic core, an ultramafic mantle, and a basaltic crust. A spectroscopic match between the HEDs and 4 Vesta along with a plausible mechanism for their transfer to Earth, perhaps as chips off V-type asteroids ejected from Vesta's southern impact basin, supports the consensus view that many of these achondritic meteorites are samples of Vesta's crust and upper mantle. The HED-Vesta connection was put to the test by the NASA Dawn mission, which spent a year in close proximity to Vesta. Measurements by Dawn's three instruments, redundant Framing Cameras (FC), a Visible-InfraRed (VIR) spectrometer, and a Gamma Ray and Neutron Detector (GRaND), along with radio science have strengthened the link. Gravity measurements by Dawn are consistent with a differentiated, silicate body, with a dense Fe-rich core. The range of pyroxene compositions determined by VIR overlaps that of the howardites. Elemental abundances determined by nuclear spectroscopy are also consistent with HED-compositions. Observations by GRaND provided a new view of Vesta inaccessible by telescopic observations. Here, we summarize the results of Dawn's geochemical investigation of Vesta and their implications.

  16. MBE growth technology for high quality strained III-V layers

    NASA Technical Reports Server (NTRS)

    Grunthaner, Frank J. (Inventor); Liu, John K. (Inventor); Hancock, Bruce R. (Inventor)

    1992-01-01

    III-V films are grown on large automatically perfect terraces of III-V substrates which have a different lattice constant, with temperature and Group II and V arrival rates chosen to give a Group III element stable surface. The growth is pulsed to inhibit Group III metal accumulation to low temperature, and to permit the film to relax to equilibrium. The method of the invention 1) minimizes starting step density on sample surface; 2) deposits InAs and GaAs using an interrupted growth mode (0.25 to 2 mono-layers at a time); 3) maintains the instantaneous surface stoichiometry during growth (As-stable for GaAs, In-stable for InAs); and 4) uses time-resolved RHEED to achieve aspects (1)-14 (3).

  17. Automata groups 

    E-print Network

    Muntyan, Yevgen

    2010-01-16

    constructed finite au- tomata which generate infinite torsion groups [Ale72, Sus79, Gri80, GS83]. Later R.I. Grigorchuk proved that the groups he constructed have intermediate growth be- tween polynomial and exponential, providing a solution to Milnor Problem...

  18. Hydra groups

    E-print Network

    Dison, Will

    2010-01-01

    We give examples of CAT(0), biautomatic, free-by-cyclic, one-relator groups which have finite-rank free subgroups of huge (Ackermannian) distortion. This leads to elementary examples of groups whose Dehn functions are similarly extravagant. This behaviour originates in manifestations of Hercules-versus-the-hydra battles in string-rewriting.

  19. Group Theatre.

    ERIC Educational Resources Information Center

    Clark, Brian

    The group interpretation approach to theatre production is defined as a method that will lead to production of plays that will appeal to "all the layers of the conscious and unconscious mind." In practice, it means that the group will develop and use resources of the theatre that orthodox companies too often ignore. The first two chapters of this…

  20. Concentration of stable elements in food products

    SciTech Connect

    Montford, M.A.; Shank, K.E.; Hendricks, C.; Oakes, T.W.

    1980-01-01

    Food samples were taken from commercial markets and analyzed for stable element content. The concentrations of most stable elements (Ag, Al, As, Au, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Cu, Fe, Hf, I, K, La, Mg, Mn, Mo, Na, Rb, Sb, Sc, Se, Sr, Ta, Th, Ti, V, Zn, Zr) were determined using multiple-element neutron activation analysis, while the concentrations of other elements (Cd, Hg, Ni, Pb) were determined using atomic absorption. The relevance of the concentrations found are noted in relation to other literature values. An earlier study was extended to include the determination of the concentration of stable elements in home-grown products in the vicinity of the Oak Ridge National Laboratory. Comparisons between the commercial and local food-stuff values are discussed.