Science.gov

Sample records for reduced superstructure solution

  1. Curvature aided efficient axial field emission from carbon nanofiber-reduced graphene oxide superstructures on tungsten wire substrate

    NASA Astrophysics Data System (ADS)

    Jha, Arunava; Roy, Rajarshi; Sen, Dipayan; Chattopadhyay, Kalyan K.

    2016-03-01

    Field emission characteristics found in reduced graphene oxide (RGO) and RGO based composite systems have always been an area of research interest mainly due to presence of prolific quasi aligned edges working as emitter sites. However, the specific role and extent of edge curvature geometry in RGO systems in regards to the enhancement of field emission has not discussed thoroughly prior to this work. In this work we demonstrate enhanced axial field emission due to top assembly of thin RGO layer over a quasi-vertically aligned carbon nanofiber thin film supported on a tungsten wire substrate. Furthermore, simulation analysis for our RGO based hybrid system using finite element modeling showed that two-stage local field amplification in RGO is responsible for the overall improvement of field emission characteristics. In support of our findings, a tentative explanation has been proposed based on the additional emission from RGO edges in between the CNF network resulting to the enhancement of axial field emission in the nanocomposite superstructure.

  2. Superstructure high efficiency photovoltaics

    NASA Technical Reports Server (NTRS)

    Wagner, M.; So, L. C.; Leburton, J. P.

    1987-01-01

    A novel class of photovoltaic cascade structures is introduced which features multijunction upper subcells. These superstructure high efficiency photovoltaics (SHEP's) exhibit enhanced upper subcell spectral response because of the additional junctions which serve to reduce bulk recombination losses by decreasing the mean collection distance for photogenerated minority carriers. Two possible electrical configurations were studied and compared: a three-terminal scheme that allows both subcells to be operated at their individual maximum power points and a two-terminal configuration with an intercell ohmic contact for series interconnection. The three-terminal devices were found to be superior both in terms of beginning-of-life expectancy and radiation tolerance. Realistic simulations of three-terminal AlGaAs/GaAs SHEP's show that one sun AMO efficiencies in excess of 26 percent are possible.

  3. Biomimetic synthesis of aragonite superstructures using hexamethylenetetramine

    SciTech Connect

    Chen Long; Huang Fangzhi; Li Shikuo; Shen Yuhua; Xie Anjian; Pan Jian; Zhang Yaping; Cai Yan

    2011-11-15

    In this paper, biomimetic synthesis of aragonite superstructures using a low molecular weight organic-hexamethylenetetramine (HMT) as an additive in the presence of CO{sub 2} supplied by an ammonium carbonate ((NH{sub 4}){sub 2}CO{sub 3}) diffusion method at room temperature was studied. The products were characterized by scanning or transmission electron microscopy, Fourier transform infrared (FT-IR) spectroscopy, X-ray powder diffractometry, and selected area electron diffraction. The results showed the aragonite superstructures especially dumbbell-flower-like ones were obtained. The formation process of calcium carbonate (CaCO{sub 3}) in HMT aqueous solution was investigated, suggesting that the products transformed from calcite to vaterite primarily, and then changed into a mixture of aragonite and calcite with an increase of reaction time. The formation mechanism of CaCO{sub 3} in HMT solution was also discussed, revealing that aragonite might be controlled by HMT molecules and NH{sub 4}{sup +} ions together. - Graphical abstract: The well-defined aragonite hierarchical superstructures are formed using hexamethylenetetramine in aqueous solution. Highlights: > Aragonite superstructures are formed with hexamethylenetetramine at about 25 deg. C. > Dumbbell-flower-like aragonite produces when hexamethylenetetramine/Ca{sup 2+}=10:1. > CaCO{sub 3} formation in hexamethylenetetramine solution violates the Ostwald ripening. > Hexamethylenetetramine and NH{sub 4}{sup +} might control the growth of aragonite together.

  4. Test of Two NB Superstructure Prototypes

    SciTech Connect

    Sekutowicz, J.

    2004-04-16

    An alternative layout of the TESLA linear collider [1], based on weakly coupled multi-cell superconducting structures (superstructures), significantly reduces investment cost due to a simplification in the RF system of the main accelerator. In January 1999, preparation of the beam test of the superstructure began in order to prove the feasibility of this layout. Progress in the preparation was reported frequently in Proceedings of TESLA Collaboration Meetings. Last year, two superstructures were installed in the TESLA Test Facility (TTF) linac at DESY to experimentally verify: methods to balance the accelerating gradient in a weakly coupled system, the stability of the energy gain for the entire train of bunches in macro-pulses and the damping of Higher Order Modes (HOMs). We present results of the first cold and beam test of these two Nb prototypes.

  5. Orbital Superstructures in Spinels

    NASA Astrophysics Data System (ADS)

    Khomskii, Daniel

    2006-03-01

    Orbital degrees of freedom often lead to specific types of orbital and spin ordering. Complicated and interesting superstructures are observed in B-sublattice of spinels. This is connected with the geometric frustration of this lattice and with the interconnection of edge-sharing MO6 octahedra, which is especially important for transition metals with partially-filled t2g levels. In some such systems (MgTi2O4, CuIr2S4, AlV2O4) there appears strange superstructures with the formation of spin gap states. In other cases (ZnV2O4) structural transitions, apparently connected with orbital ordering, are followed by long-range magnetic ordering. Last but not least, the famous Verwey transition in magnetite Fe3O4 leads to a very complicated structural pattern, accompanied by the appearance of ferroelectricity. In this talk I will discuss all these examples, paying main attention to an interplay of charge, spin and orbital degrees of freedom. In particular, for MgTi2O4, and CuIr2S4 we proposed the picture of orbitally-driven Peierls state [1]. Similar phenomenon can also explain situation in ZnV2O4 [2], although the corresponding superstructure has not yet been observed experimentally. Finally, I propose the model of charge and orbital ordering in magnetite [3], which uses the idea of an interplay of site- and bond-centered ordering [4] and which seems to explain both the structural data and the presence of ferroelectricity in Fe3O4 below Verwey transition. [1] D.I.Khomskii and T.Mizokawa, Phys.Rev.Lett. 94, 156402 (2005); [2] Hua Wu, T.Mizokawa and D.I.Khomskii, unpublished; [3] D.I.Khomskii, unpublished; [4] D.V.Efremov, J.van den Brink and D.I.Khomskii, Nature Mater. 3, 853 (2004)

  6. Optical properties of ordered superstructures formed from cadmium and lead chalcogenide colloidal nanocrystals.

    PubMed

    Ushakova, Elena V; Cherevkov, Sergei A; Litvin, Aleksandr P; Parfenov, Peter S; Zakharov, Viktor V; Dubavik, Aliaksei; Fedorov, Anatoly V; Baranov, Alexander V

    2016-01-25

    The optical properties of three-dimensional ordered superstructures formed on glass substrates by self-assembly of cadmium selenide or lead sulfide nanocrystals (NCs) are investigated and compared to the optical properties of the initial NC colloidal solutions. The formation of the superstructures is strongly correlated to the presence of oleic acid molecules on the surface of the NCs. It is found that the absorption band of the NCs in the superstructures is broadened and shifted to shorter wavelengths in comparison with the absorption band of the NCs in solution. The luminescence spectra of the NCs in the superstructures also differ from the spectra of the NCs in solution. The observed modification of optical properties of superstructures is a manifestation of interactions between the NCs and the chemical environment within the superstructures. PMID:26832598

  7. Electron imaging of pyrrhotite superstructures.

    PubMed

    Pierce, L; Buseck, P R

    1974-12-27

    Natural pyrrhotites, when studied by high resolution electron microscopy, yield crystallographic information on a unit cell scale. Structural heterogeneity is prominent. The many reported superstructures are interpretable through an antiphase model. The 5C pyrrhotite superstructure results from an ordered sequence of antiphase domains while the higher temperature NC type results from a disordered sequence. PMID:17833934

  8. Finding Strategic Solutions to Reduce Truancy

    ERIC Educational Resources Information Center

    Reid, Ken

    2010-01-01

    This article focuses on recent developments to find strategic solutions to the problem of truancy. It considers issues related to defining truancy and why reducing truancy matters before considering what causes truancy. The article concentrates upon seven areas where further work is needed: the role of parents (and carers); early intervention,…

  9. Simple solutions for reduced fish farm hazards.

    PubMed

    Myers, Melvin L; Cole, Henry P

    2009-01-01

    Aquaculture poses emerging challenges for agricultural safety and health. Fish farming has many of the same hazards as other types of farming, but it also poses additional hazards associated with water impoundments and night-time work. In a multidisciplinary approach, researchers from four universities are identifying occupational hazards in fish farming and identifying no-cost or low-cost "simple solutions" to reduce or eliminate them. Simple solutions are discovered through farm visits so as to understand the countermeasures that individual stakeholders have taken to protect their workforce, and these countermeasures are documented and photographed to inform other farmers of these solutions. Equipping tractors with rollover protective structures is a standard practice to protect operators from serious injury in the event of an overturn. Other solutions identified include eliminating the need to climb feed bins to open and close the hatch for feed delivery by using a pull-cable at ground level. This simple technology eliminates the exposure to falling from an elevation, a risk that accounts for at least one reported death of a worker on a fish farm. Another solution is to replace metal paddles on a hatchery trough with plastic paddles that if and when entangled in a worker's hair or clothing slip on the rotating drive shaft and thus reduce laceration and entanglement injuries. Another simple solution to prevent entanglements in large pond aerators, used to mechanically dissolve oxygen into the water, that are operated by farm tractor power take-off shafts is to use electrically powered aerators. Bubble-type aerators are safer than electrically powered paddle aerators because workers are shielded from moving parts. Many additional simple solutions have been identified for a range of tasks in this environment. PMID:19437271

  10. Silver-colloid-nucleated cytochrome c superstructures encapsulated in silica nanoarchitectures.

    PubMed

    Wallace, Jean Marie; Dening, Brett M; Eden, Kristin B; Stroud, Rhonda M; Long, Jeffrey W; Rolison, Debra R

    2004-10-12

    We recently discovered that self-organized superstructures of the heme protein cytochrome c (cyt. c) are nucleated in buffer by gold nanoparticles. The protein molecules within the superstructure survive both silica sol-gel encapsulation and drying from supercritical carbon dioxide to form air-filled biocomposite aerogels that exhibit gas-phase binding activity for nitric oxide. In this investigation, we report that viable proteins are present in biocomposite aerogels when the nucleating metal nanoparticle is silver rather than gold. Silver colloids were synthesized via reduction of an aqueous solution of Ag+ using either citrate or borohydride reductants. As determined by transmission electron microscopy and UV-visible absorption spectroscopy, the silver nanoparticles vary in size and shape depending on the synthetic route, which affects the fraction of cyt. c that survives the processing necessary to form a biocomposite aerogel. Silver colloids synthesized via the citrate preparation are polydisperse, with sizes ranging from 1 to 100 nm, and lead to low cyt. c viability in the dried bioaerogels (approximately 15%). Protein superstructures nucleated at approximately 10-nm Ag colloids prepared via the borohydride route, including citrate stabilization of the borohydride-reduced metal, retain significant protein viability within the bioaerogels (approximately 45%). PMID:15461518

  11. Proposal for superstructure based high efficiency photovoltaics

    NASA Technical Reports Server (NTRS)

    Wagner, M.; Leburton, J. P.

    1986-01-01

    A novel class of cascade structures is proposed which features multijunction upper subcells, referred to as superstructure high-efficiency photovoltaics (SHEPs). The additional junctions enhance spectral response and improve radiation tolerance by reducing bulk recombination losses. This is important because ternary III-V alloys, which tend to have short minority-carrier diffusion lengths, are the only viable materials for the high-bandgap upper subcells required for cascade solar cells. Realistic simulations of AlGaAs SHEPs show that one-sun AM0 efficiencies in excess of 26 percent are possible.

  12. A green strategy to prepare metal oxide superstructure from metal-organic frameworks.

    PubMed

    Song, Yonghai; Li, Xia; Wei, Changting; Fu, Jinying; Xu, Fugang; Tan, Hongliang; Tang, Juan; Wang, Li

    2015-01-01

    Metal or metal oxides with diverse superstructures have become one of the most promising functional materials in sensor, catalysis, energy conversion, etc. In this work, a novel metal-organic frameworks (MOFs)-directed method to prepare metal or metal oxide superstructure was proposed. In this strategy, nodes (metal ions) in MOFs as precursors to form ordered building blocks which are spatially separated by organic linkers were transformed into metal oxide micro/nanostructure by a green method. Two kinds of Cu-MOFs which could reciprocally transform by changing solvent were prepared as a model to test the method. Two kinds of novel CuO with three-dimensional (3D) urchin-like and 3D rods-like superstructures composed of nanoparticles, nanowires and nanosheets were both obtained by immersing the corresponding Cu-MOFs into a NaOH solution. Based on the as-formed CuO superstructures, a novel and sensitive nonenzymatic glucose sensor was developed. The small size, hierarchical superstructures and large surface area of the resulted CuO superstructures eventually contribute to good electrocatalytic activity of the prepared sensor towards the oxidation of glucose. The proposed method of hierarchical superstructures preparation is simple, efficient, cheap and easy to mass production, which is obviously superior to pyrolysis. It might open up a new way for hierarchical superstructures preparation. PMID:25669731

  13. A Green Strategy to Prepare Metal Oxide Superstructure from Metal-Organic Frameworks

    PubMed Central

    Song, Yonghai; Li, Xia; Wei, Changting; Fu, Jinying; Xu, Fugang; Tan, Hongliang; Tang, Juan; Wang, Li

    2015-01-01

    Metal or metal oxides with diverse superstructures have become one of the most promising functional materials in sensor, catalysis, energy conversion, etc. In this work, a novel metal-organic frameworks (MOFs)-directed method to prepare metal or metal oxide superstructure was proposed. In this strategy, nodes (metal ions) in MOFs as precursors to form ordered building blocks which are spatially separated by organic linkers were transformed into metal oxide micro/nanostructure by a green method. Two kinds of Cu-MOFs which could reciprocally transform by changing solvent were prepared as a model to test the method. Two kinds of novel CuO with three-dimensional (3D) urchin-like and 3D rods-like superstructures composed of nanoparticles, nanowires and nanosheets were both obtained by immersing the corresponding Cu-MOFs into a NaOH solution. Based on the as-formed CuO superstructures, a novel and sensitive nonenzymatic glucose sensor was developed. The small size, hierarchical superstructures and large surface area of the resulted CuO superstructures eventually contribute to good electrocatalytic activity of the prepared sensor towards the oxidation of glucose. The proposed method of hierarchical superstructures preparation is simple, efficient, cheap and easy to mass production, which is obviously superior to pyrolysis. It might open up a new way for hierarchical superstructures preparation. PMID:25669731

  14. Topological Insulators from Electronic Superstructures

    NASA Astrophysics Data System (ADS)

    Sugita, Yusuke; Motome, Yukitoshi

    2016-07-01

    The possibility of realizing topological insulators by the spontaneous formation of electronic superstructures is theoretically investigated in a minimal two-orbital model including both the spin-orbit coupling and electron correlations on a triangular lattice. Using the mean-field approximation, we show that the model exhibits several different types of charge-ordered insulators, where the charge disproportionation forms a honeycomb or kagome superstructure. We find that the charge-ordered insulators in the presence of strong spin-orbit coupling can be topological insulators showing quantized spin Hall conductivity. Their band gap is dependent on electron correlations as well as the spin-orbit coupling, and even vanishes while showing the massless Dirac dispersion at the transition to a trivial charge-ordered insulator. Our results suggest a new route to realize and control topological states of quantum matter by the interplay between the spin-orbit coupling and electron correlations.

  15. Long- and short-range order in the Pd6B monoclinic superstructure and M6X5 and M6X allied superstructures

    NASA Astrophysics Data System (ADS)

    Gusev, A. I.

    2011-07-01

    Symmetry analysis of the Pd6B monoclinic superstructure (space group C2/ c) formed in the cubic (with the B1 structure) solid solution of boron in palladium (PdB y ) has been carried out. The formation of this superstructure proceeds as a first-order phase transition via the disorder-order channel including nine nonequivalent superstructure vectors of four stars { k 10}, { k 4}, { k 3}, and { k 0}. For the Pd6B monoclinic super-structure (space group C2/ c), the distribution function for boron atoms is calculated and the interval of admissible values of the long-range order parameters is defined. It is shown that the transition channel determined in this way coincides with the channel in which the M6X monoclinic superstructure (space group C2) is formed; therefore, the Pd6B superstructure can also be described in space group C2 to the same degree of accuracy. The higher symmetry of the monoclinic model (space group C2/ c) suggests that it describes the structure of the Pd6B phase (Pd6B□5), as well as of mutually inverse phases M6X□5 and M6X5□, more adequately than the model with space group C2. It is shown that superstructures of the M6X□5 type (space groups C2/ c, C2, C2/ m, and P31) and inverse superstructures of the M6X5□ type with the same space groups have the positions of the nearest surrounding of metal atoms by two types of nonmetallic sublattice sites located in the first and second coordination spheres.

  16. Unusually Stable Triazine-based Organic Superstructures.

    PubMed

    Jung, Sun-Min; Kim, Dongwook; Shin, Dongbin; Mahmood, Javeed; Park, Noejung; Lah, Myoung Soo; Jeong, Hu Young; Baek, Jong-Beom

    2016-06-20

    Solid-state reactions have been rapidly gaining popularity in organic chemistry owing to their simplicity, efficiency, and selectivity compared to liquid-phase reactions. Herein, we describe the formation of superstructures through the solid-state reaction of an organic single-crystal. The superstructure of 5,5',5''-(1,3,5-triazine-2,4,6-triyl)triisophthalonitrile (TIPN) can be formed by cyclotrimerization of 1,3,5-tricyanobenzene (TCB) single crystals. The TIPN superstructure was confirmed by single crystal X-ray diffraction and visualized by transmission electron microscopy. The superstructure has hexagonally packed 1-dimensional (1D) channels along the crystal axis. Furthermore, the superstructure arises from interdigitated nitrile interactions in the crystal lattice, and thus has electron-beam tolerance and very high thermal stability. PMID:27119651

  17. Permanent excimer superstructures by supramolecular networking of metal quantum clusters.

    PubMed

    Santiago-Gonzalez, Beatriz; Monguzzi, Angelo; Azpiroz, Jon Mikel; Prato, Mirko; Erratico, Silvia; Campione, Marcello; Lorenzi, Roberto; Pedrini, Jacopo; Santambrogio, Carlo; Torrente, Yvan; De Angelis, Filippo; Meinardi, Francesco; Brovelli, Sergio

    2016-08-01

    Excimers are evanescent quasi-particles that typically form during collisional intermolecular interactions and exist exclusively for their excited-state lifetime. We exploited the distinctive structure of metal quantum clusters to fabricate permanent excimer-like colloidal superstructures made of ground-state noninteracting gold cores, held together by a network of hydrogen bonds between their capping ligands. This previously unknown aggregation state of matter, studied through spectroscopic experiments and ab initio calculations, conveys the photophysics of excimers into stable nanoparticles, which overcome the intrinsic limitation of excimers in single-particle applications-that is, their nearly zero formation probability in ultra-diluted solutions. In vitro experiments demonstrate the suitability of the superstructures as nonresonant intracellular probes and further reveal their ability to scavenge reactive oxygen species, which enhances their potential as anticytotoxic agents for biomedical applications. PMID:27493181

  18. Permanent excimer superstructures by supramolecular networking of metal quantum clusters

    NASA Astrophysics Data System (ADS)

    Santiago-Gonzalez, Beatriz; Monguzzi, Angelo; Azpiroz, Jon Mikel; Prato, Mirko; Erratico, Silvia; Campione, Marcello; Lorenzi, Roberto; Pedrini, Jacopo; Santambrogio, Carlo; Torrente, Yvan; De Angelis, Filippo; Meinardi, Francesco; Brovelli, Sergio

    2016-08-01

    Excimers are evanescent quasi-particles that typically form during collisional intermolecular interactions and exist exclusively for their excited-state lifetime. We exploited the distinctive structure of metal quantum clusters to fabricate permanent excimer-like colloidal superstructures made of ground-state noninteracting gold cores, held together by a network of hydrogen bonds between their capping ligands. This previously unknown aggregation state of matter, studied through spectroscopic experiments and ab initio calculations, conveys the photophysics of excimers into stable nanoparticles, which overcome the intrinsic limitation of excimers in single-particle applications—that is, their nearly zero formation probability in ultra-diluted solutions. In vitro experiments demonstrate the suitability of the superstructures as nonresonant intracellular probes and further reveal their ability to scavenge reactive oxygen species, which enhances their potential as anticytotoxic agents for biomedical applications.

  19. DNA assembly of nanoparticle superstructures for controlled biological delivery and elimination

    NASA Astrophysics Data System (ADS)

    Chou, Leo Y. T.; Zagorovsky, Kyryl; Chan, Warren C. W.

    2014-02-01

    The assembly of nanomaterials using DNA can produce complex nanostructures, but the biological applications of these structures remain unexplored. Here, we describe the use of DNA to control the biological delivery and elimination of inorganic nanoparticles by organizing them into colloidal superstructures. The individual nanoparticles serve as building blocks, whose size, surface chemistry and assembly architecture dictate the overall superstructure design. These superstructures interact with cells and tissues as a function of their design, but subsequently degrade into building blocks that can escape biological sequestration. We demonstrate that this strategy reduces nanoparticle retention by macrophages and improves their in vivo tumour accumulation and whole-body elimination. Superstructures can be further functionalized to carry and protect imaging or therapeutic agents against enzymatic degradation. These results suggest a different strategy to engineer nanostructure interactions with biological systems and highlight new directions in the design of biodegradable and multifunctional nanomedicine.

  20. Antisolvent crystallization approach to construction of CuI superstructures with defined geometries.

    PubMed

    Kozhummal, Rajeevan; Yang, Yang; Güder, Firat; Küçükbayrak, Umut M; Zacharias, Margit

    2013-03-26

    A facile high-yield production of cuprous iodide (CuI) superstructures is reported by antisolvent crystallization using acetonitrile/water as a solvent/antisolvent couple under ambient conditions. In the presence of trace water, the metastable water droplets act as templates to induce the precipitation of hollow spherical CuI superstructures consisting of orderly aligned building blocks after drop coating. With water in excess in the mixed solution, an instant precipitation of CuI random aggregates takes place due to rapid crystal growth via ion-by-ion attachment induced by a strong antisolvent effect. However, this uncontrolled process can be modified by adding polymer polyvinyl pyrrolidone (PVP) in water to restrict the size of initially formed CuI crystal nuclei through the effective coordination effect of PVP. As a result, CuI superstructures with a cuboid geometry are constructed by gradual self-assembly of the small CuI crystals via oriented attachment. The precipitated CuI superstructures have been used as competent adsorbents to remove organic dyes from the water due to their mesocrystal feature. Besides, the CuI superstructures have been applied either as a self-sacrificial template or only as a structuring template for the flexible design of other porous materials such as CuO and TiO2. This system provides an ideal platform to simultaneously investigate the superstructure formation enforced by antisolvent crystallization with and without organic additives. PMID:23441989

  1. Assembly of metals and nanoparticles into novel nanocomposite superstructures

    PubMed Central

    Xu, Jiaquan; Chen, Lianyi; Choi, Hongseok; Konish, Hiromi; Li, Xiaochun

    2013-01-01

    Controlled assembly of nanoscale objects into superstructures is of tremendous interests. Many approaches have been developed to fabricate organic-nanoparticle superstructures. However, effective fabrication of inorganic-nanoparticle superstructures (such as nanoparticles linked by metals) remains a difficult challenge. Here we show a novel, general method to assemble metals and nanoparticles rationally into nanocomposite superstructures. Novel metal-nanoparticle superstructures are achieved by self-assembly of liquid metals and nanoparticles in immiscible liquids driven by reduction of free energy. Superstructures with various architectures, such as metal-core/nanoparticle-shell, nanocomposite-core/nanoparticle-shell, network of metal-linked core/shell nanostructures, and network of metal-linked nanoparticles, were successfully fabricated by simply tuning the volume ratio between nanoparticles and liquid metals. Our approach provides a simple, general way for fabrication of numerous metal-nanoparticle superstructures and enables a rational design of these novel superstructures with desired architectures for exciting applications.

  2. 46 CFR 42.20-40 - Standard height of superstructure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Standard height of superstructure. 42.20-40 Section 42... FOREIGN VOYAGES BY SEA Freeboards § 42.20-40 Standard height of superstructure. (a) The standard height of a superstructure shall be as given in table 42.20-40(a): Table 42.20-40(a) Standard Heights (in...

  3. 46 CFR 42.20-40 - Standard height of superstructure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Standard height of superstructure. 42.20-40 Section 42... FOREIGN VOYAGES BY SEA Freeboards § 42.20-40 Standard height of superstructure. (a) The standard height of a superstructure shall be as given in Table 42.20-40(a): Table 42.20-40(a) Standard Heights (in...

  4. 46 CFR 42.20-40 - Standard height of superstructure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Standard height of superstructure. 42.20-40 Section 42... FOREIGN VOYAGES BY SEA Freeboards § 42.20-40 Standard height of superstructure. (a) The standard height of a superstructure shall be as given in table 42.20-40(a): Table 42.20-40(a) Standard Heights (in...

  5. 46 CFR 42.20-40 - Standard height of superstructure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Standard height of superstructure. 42.20-40 Section 42... FOREIGN VOYAGES BY SEA Freeboards § 42.20-40 Standard height of superstructure. (a) The standard height of a superstructure shall be as given in Table 42.20-40(a): Table 42.20-40(a) Standard Heights (in...

  6. 46 CFR 42.20-40 - Standard height of superstructure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Standard height of superstructure. 42.20-40 Section 42... FOREIGN VOYAGES BY SEA Freeboards § 42.20-40 Standard height of superstructure. (a) The standard height of a superstructure shall be as given in Table 42.20-40(a): Table 42.20-40(a) Standard Heights (in...

  7. Influence of superstructure geometry on the mechanical behavior of zirconia implant abutments: a finite element analysis.

    PubMed

    Geringer, Alexander; Diebels, Stefan; Nothdurft, Frank P

    2014-12-01

    To predict the clinical performance of zirconia abutments, it is crucial to examine the mechanical behavior of different dental implant-abutment connection configurations. The international standard protocol for dynamic fatigue tests of dental implants (ISO 14801) allows comparing these configurations using standardized superstructure geometries. However, from a mechanical point of view, the geometry of clinical crowns causes modified boundary conditions. The purpose of this finite element (FE) study was to evaluate the influence of the superstructure geometry on the maximum stress values of zirconia abutments with a conical implant-abutment connection. Geometry models of the experimental setup described in ISO 14801 were generated using CAD software following the reconstruction of computerized tomography scans from all relevant components. These models served as a basis for an FE simulation. To reduce the numerical complexity of the FE model, the interaction between loading stamp and superstructure geometry was taken into account by defining the boundary conditions with regard to the frictional force. The results of the FE simulations performed on standardized superstructure geometry and anatomically shaped crowns showed a strong influence of the superstructure geometry and related surface orientations on the mechanical behavior of the underlying zirconia abutments. In conclusion, ISO testing of zirconia abutments should be accompanied by load-bearing capacity testing under simulated clinical conditions to predict clinical performance. PMID:25029078

  8. Reducing errors in the GRACE gravity solutions using regularization

    NASA Astrophysics Data System (ADS)

    Save, Himanshu; Bettadpur, Srinivas; Tapley, Byron D.

    2012-09-01

    The nature of the gravity field inverse problem amplifies the noise in the GRACE data, which creeps into the mid and high degree and order harmonic coefficients of the Earth's monthly gravity fields provided by GRACE. Due to the use of imperfect background models and data noise, these errors are manifested as north-south striping in the monthly global maps of equivalent water heights. In order to reduce these errors, this study investigates the use of the L-curve method with Tikhonov regularization. L-curve is a popular aid for determining a suitable value of the regularization parameter when solving linear discrete ill-posed problems using Tikhonov regularization. However, the computational effort required to determine the L-curve is prohibitively high for a large-scale problem like GRACE. This study implements a parameter-choice method, using Lanczos bidiagonalization which is a computationally inexpensive approximation to L-curve. Lanczos bidiagonalization is implemented with orthogonal transformation in a parallel computing environment and projects a large estimation problem on a problem of the size of about 2 orders of magnitude smaller for computing the regularization parameter. Errors in the GRACE solution time series have certain characteristics that vary depending on the ground track coverage of the solutions. These errors increase with increasing degree and order. In addition, certain resonant and near-resonant harmonic coefficients have higher errors as compared with the other coefficients. Using the knowledge of these characteristics, this study designs a regularization matrix that provides a constraint on the geopotential coefficients as a function of its degree and order. This regularization matrix is then used to compute the appropriate regularization parameter for each monthly solution. A 7-year time-series of the candidate regularized solutions (Mar 2003-Feb 2010) show markedly reduced error stripes compared with the unconstrained GRACE release 4

  9. Intermolecular interactions of reduced nicotinamide adenine dinucleotide (NADH) in solution

    NASA Astrophysics Data System (ADS)

    Jasensky, Joshua; Junaid Farooqi, M.; Urayama, Paul

    2008-10-01

    Nicotinamide adenine dinucleotide (NAD^+/NADH) is a coenzyme involved in cellular respiration as an electron transporter. In aqueous solution, the molecule exhibits a folding transition characterized by the stacking of its aromatic moieties. A transition to an unfolded conformation is possible using chemical denaturants like methanol. Because the reduced NADH form is fluorescent, the folding transition can be monitored using fluorescence spectroscopy, e.g., via a blue-shift in the UV-excited emission peak upon methanol unfolding. Here we present evidence of interactions between NADH molecules in solution. We measure the excited-state emission from NADH at various concentrations (1-100 μM in MOPS buffer, pH 7.5; 337-nm wavelength excitation). Unlike for the folded form, the emission peak wavelength of the unfolded form is concentration dependent, exhibiting a red-shift with higher NADH concentration, suggesting the presence of intermolecular interactions. An understanding of NADH spectra in solution would assist in interpreting intercellular NADH measurements used for the in vivo monitoring cellular energy metabolism.

  10. Environmental impact of offshore operation reduced using innovative engineering solutions

    SciTech Connect

    Ritchie, C.J.; Wensel, E.A.; Edelblum, L.S.; Beal, D.

    1994-12-31

    The North Dauphin Island Tract 73 platform is located in eleven feet (3.4 m) of water and one mile (1.6 km) from shore in Mobile Bay, Alabama. The platform is designed to dehydrate and compress up to 70 MMSCFD (1.98 x 10{sup 6} SM{sup 3}) from five remote gas production wells. Located near the city of Mobile, Alabama, the surrounding metropolitan and coastal areas has multiple uses including manufacturing, tourism, commercial and sport fishing, and wetlands and wildlife conservation. The multiple and interdependent economic uses of the area required that the platform be designed to minimize any adverse environmental impact. A cost-effective environmental engineering solution was desired at the design phase of the project. A water catchment, containment and disposal system was designed to meet the zero discharge requirement. Pollution from air emissions was reduced by the installation of lean burning engines. A floatover installation process was used to prevent dredging of the bay, thus protecting the bay water quality. An aesthetically concealing paint and lighting scheme was chosen and applied to the entire structure. These cost-effective engineering solutions during the design phase of the project saved time and money over the life of the project. All regulatory permits were obtained in a timely manner, with little or no opposition. The operator of the North Dauphin Island Development won several environmental awards due to the implementation of innovative solutions and their commitment to conservation of the natural environment.

  11. Anterior all-ceramic superstructures: chance or risk?

    PubMed

    Rinke, Sven

    2015-03-01

    The use of zirconia abutments for single-tooth restorations is well documented and supported by clinical studies with observational periods of up to 5 years. However, data for fixed partial dentures (FPDs) on all-ceramic abutments are lacking. Therefore, this indication cannot yet be generally recommended. Based on the available clinical studies, it can be assumed that the treatment results for anterior restorations can be improved by using all-ceramic abutments, especially in situations with a reduced thickness of the peri-implant soft tissues (< 2 mm). Zirconia abutments for single-tooth restorations can be restored with glass-ceramic crowns on a lithium-disilicate base or crowns with oxide-ceramic structures (alumina or zirconia). If the restorations are cemented adhesively, then all of the cement residues must be carefully removed. Superstructures based on zirconia ceramics can be removed to a certain degree if they are cemented temporarily or screwfixed with directly veneered abutments. However, prior to providing a general recommendation for temporary cementation or screw-fixation of all-ceramic superstructures, additional clinical data are needed. PMID:25606583

  12. Reducing dropout of contact lens wear with Biotrue multipurpose solution

    PubMed Central

    Rah, Marjorie J; Merchea, Mohinder M; Doktor, Marianne Q

    2014-01-01

    Purpose To evaluate whether the use of Biotrue multipurpose solution (MPS) could significantly reduce the likelihood with which patients drop out of using daily wear contact lenses (CLs) amongst 18–44-year-old frequent replacement CL wearers. Methods Daily wear CL subjects habitually using MPSs (other than Biotrue MPS) who reported an intent to imminently drop out of CL wear because of comfort and dryness complaints were recruited to participate in this investigation. Subjects were switched to Biotrue MPS and continued to use habitual CL types with the new MPS for 2 weeks. Subjects completed an online satisfaction questionnaire at baseline and after 2 weeks to assess the change in symptoms and the intent to drop out of CL wear. Six months after completion of the initial study, a follow-up survey was administered to a subset of the initial participants. Results A total of 153 daily wear (silicone hydrogel and hydrogel) subjects completed this 2-week study with Biotrue MPS. When measuring those with the highest propensity to drop out of lens wear (n=93) after switching to Biotrue MPS, 90% of subjects significantly reduced their likelihood of dropping out of CL wear (P<0.0001). Online interviews were conducted with 73 of the study participants 6 months after completion of the initial study. A total of 93% of participants responded that they were still wearing CLs at least once per week. Of the 7% of respondents who were not currently wearing lenses 6 months after the initial study, two had dropped out of lens wear completely, and three still wore lenses less than once per week. Conclusion Patients intending to drop out of CL wear due to discomfort and dryness significantly reduced their propensity of discontinuing lens wear following use of Biotrue MPS. Six months after completion of the study, 93% of patients were still wearing CLs at least once per week. PMID:24493920

  13. Optical characteristics of bending multimode superstructure fiber gratings.

    PubMed

    Fu, Ming-Yue; Liu, Wen-Fung; Sheng, Hao-Jan; Ai, Lung; Peng, Hsin-Wen; Tien, Chuen-Lin

    2009-09-01

    The dispersion characteristics of superstructure fiber gratings written in multimode fibers and side-polished multimode fibers are investigated at different bending curvatures. The experimental results show that the group time delay in multimode superstructure fiber gratings can be tuned more easily than that of superstructure gratings in single-mode fiber. This method can provide tunable dispersion of superstructure fiber gratings by controlling the bending curvatures for application in dispersion compensators, fiber sensors, or suitable optical filters of optical communication systems. PMID:19724306

  14. Au nanorod helical superstructures with designed chirality.

    PubMed

    Lan, Xiang; Lu, Xuxing; Shen, Chenqi; Ke, Yonggang; Ni, Weihai; Wang, Qiangbin

    2015-01-14

    A great challenge for nanotechnology is to controllably organize anisotropic nanomaterials into well-defined three-dimensional superstructures with customized properties. Here we successfully constructed anisotropic Au nanorod (AuNR) helical superstructures (helices) with tailored chirality in a programmable manner. By designing the 'X' pattern of the arrangement of DNA capturing strands (15nt) on both sides of a two-dimensional DNA origami template, AuNRs functionalized with the complementary DNA sequences were positioned on the origami and were assembled into AuNR helices with the origami intercalated between neighboring AuNRs. Left-handed (LH) and right-handed (RH) AuNR helices were conveniently accomplished by solely tuning the mirrored-symmetric 'X' patterns of capturing strands on the origami. The inter-rod distance was precisely defined as 14 nm and inter-rod angle as 45°, thus a full helix contains 9 AuNRs with its length up to about 220 nm. By changing the AuNR/origami molar ratio in the assembly system, the average number of AuNR in the helices was tuned from 2 to 4 and 9. Intense chiroptical activities arose from the longest AuNR helices with a maximum anisotropy factor of ∼0.02, which is highly comparable to the reported macroscopic AuNR assemblies. We expect that our strategy of origami templated assembly of anisotropic chiral superstructures would inspire the bottom-up fabrication of optically active nanostructures and shed light on a variety of applications, such as chiral fluids, chiral signal amplification, and fluorescence combined chiral spectroscopy. PMID:25516475

  15. 11. BUOY DECK, NEAR PILOT HOUSE SUPERSTRUCTURE, LOOKING TOWARDS HATCH ...

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

    11. BUOY DECK, NEAR PILOT HOUSE SUPERSTRUCTURE, LOOKING TOWARDS HATCH DOOR INTO WINCH ROOM IN THE SUPERSTRUCTURE (LABELED AS FASSAGE & HYDRAULIC MACHINERY ON PLAN), SHOWING UNDERSIDE OF GEARED WHEEL OF BOOM. - U.S. Coast Guard Cutter WHITE LUPINE, U.S. Coast Guard Station Rockland, east end of Tillson Avenue, Rockland, Knox County, ME

  16. 11. BUOY DECK, NEAR PILOT HOUSE SUPERSTRUCTURE, LOOKING TOWARDS HATCH ...

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

    11. BUOY DECK, NEAR PILOT HOUSE SUPERSTRUCTURE, LOOKING TOWARDS HATCH DOOR INTO WINCH ROOM IN THE SUPERSTRUCTURE (LABELED AT PASSAGE & HYDRAULIC MACHINERY ON PLAN). - U.S. Coast Guard Cutter WHITE HEATH, USGS Integrated Support Command Boston, 427 Commercial Street, Boston, Suffolk County, MA

  17. 46 CFR 45.109 - Strength of superstructures and deckhouses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Strength of superstructures and deckhouses. 45.109... LOAD LINES Conditions of Assignment § 45.109 Strength of superstructures and deckhouses. Each... approved assigning authority with regard to general strength and weathertightness. The Commandant may...

  18. 46 CFR 45.109 - Strength of superstructures and deckhouses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Strength of superstructures and deckhouses. 45.109... LOAD LINES Conditions of Assignment § 45.109 Strength of superstructures and deckhouses. Each... approved assigning authority with regard to general strength and weathertightness. The Commandant may...

  19. 46 CFR 45.61 - Correction for superstructures and trunks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Correction for superstructures and trunks. 45.61 Section 45.61 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD...-half of the standard superstructure height (H s) determined by the formula: Percentage=(E/2L)...

  20. 5. NORTH SIDE OF SUPERSTRUCTURE, FACING SOUTH ON MARKET STREET ...

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

    5. NORTH SIDE OF SUPERSTRUCTURE, FACING SOUTH ON MARKET STREET BETWEEN 44TH AND 45TH STREETS. DETAIL OF BARREL VAULTS ON UNDERSIDE OF SUPERSTRUCTURE. - Market Street Elevated Railway, Market Street between Sixty-ninth & Forty-sixth Streets, Philadelphia, Philadelphia County, PA

  1. 46 CFR 42.20-50 - Effective length of superstructure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... standard height shall be its length. (b) In all cases where an enclosed superstructure of standard height... the length modified by the ratio of b/Bs, where: “b” is the breadth of the superstructure at the middle of its length; “Bs” is the breadth of the vessel at the middle of the length of the...

  2. 46 CFR 42.20-50 - Effective length of superstructure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... standard height shall be its length. (b) In all cases where an enclosed superstructure of standard height... the length modified by the ratio of b/Bs, where: “b” is the breadth of the superstructure at the middle of its length; “Bs” is the breadth of the vessel at the middle of the length of the...

  3. 46 CFR 42.20-50 - Effective length of superstructure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Effective length of superstructure. 42.20-50 Section 42.20-50 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES DOMESTIC AND FOREIGN VOYAGES BY SEA Freeboards § 42.20-50 Effective length of superstructure. (a) Except as provided for in paragraph (b) of this section the...

  4. 46 CFR 42.20-50 - Effective length of superstructure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... standard height shall be its length. (b) In all cases where an enclosed superstructure of standard height... the length modified by the ratio of b/Bs, where: “b” is the breadth of the superstructure at the middle of its length; “Bs” is the breadth of the vessel at the middle of the length of the...

  5. 46 CFR 42.20-50 - Effective length of superstructure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... standard height shall be its length. (b) In all cases where an enclosed superstructure of standard height... the length modified by the ratio of b/Bs, where: “b” is the breadth of the superstructure at the middle of its length; “Bs” is the breadth of the vessel at the middle of the length of the...

  6. 46 CFR 42.15-5 - Superstructure end bulkheads.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Superstructure end bulkheads. 42.15-5 Section 42.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES DOMESTIC AND FOREIGN VOYAGES BY SEA Conditions of Assignment of Freeboard § 42.15-5 Superstructure end bulkheads. (a) Bulkheads at exposed ends of enclosed...

  7. 46 CFR 45.58 - Correction: Short superstructure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Correction: Short superstructure. 45.58 Section 45.58 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES Freeboards § 45.58 Correction: Short superstructure. The minimum freeboard in summer for a type B vessel...

  8. 46 CFR 45.58 - Correction: Short superstructure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Correction: Short superstructure. 45.58 Section 45.58 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES Freeboards § 45.58 Correction: Short superstructure. The minimum freeboard in summer for a type B vessel...

  9. Direct growth of comet-like superstructures of Au-ZnO submicron rod arrays by solvothermal soft chemistry process

    SciTech Connect

    Shen Liming; Bao, Ningzhong Yanagisawa, Kazumichi; Zheng, Yanqing; Domen, Kazunari; Gupta, Arunava; Grimes, Craig A.

    2007-01-15

    The synthesis, characterization and proposed growth process of a new kind of comet-like Au-ZnO superstructures are described here. This Au-ZnO superstructure was directly created by a simple and mild solvothermal reaction, dissolving the reactants of zinc acetate dihydrate and hydrogen tetrachloroaurate tetrahydrate (HAuCl{sub 4}.4H{sub 2}O) in ethylenediamine and taking advantage of the lattice matching growth between definitized ZnO plane and Au plane and the natural growth habit of the ZnO rods along [001] direction in solutions. For a typical comet-like Au-ZnO superstructure, its comet head consists of one hemispherical end of a central thick ZnO rod and an outer Au-ZnO thin layer, and its comet tail consists of radially standing ZnO submicron rod arrays growing on the Au-ZnO thin layer. These ZnO rods have diameters in range of 0.2-0.5 {mu}m, an average aspect ratio of about 10, and lengths of up to about 4 {mu}m. The morphology, size and structure of the ZnO superstructures are dependent on the concentration of reactants and the reaction time. The HAuCl{sub 4}.4H{sub 2}O plays a key role for the solvothermal growth of the comet-like superstructure, and only are ZnO fibers obtained in absence of the HAuCl{sub 4}.4H{sub 2}O. The UV-vis absorption spectrum shows two absorptions at 365-390 nm and 480-600 nm, respectively attributing to the characteristic of the ZnO wide-band semiconductor material and the surface plasmon resonance of the Au particles. - Graphical abstract: One-step solvothermal synthesis of novel comet-like superstructures of radially standing ZnO submicron rod arrays.

  10. Diet change—a solution to reduce water use?

    NASA Astrophysics Data System (ADS)

    Jalava, M.; Kummu, M.; Porkka, M.; Siebert, S.; Varis, O.

    2014-07-01

    Water and land resources are under increasing pressure in many parts of the globe. Diet change has been suggested as a measure to contribute to adequate food security for the growing population. This paper assesses the impact of diet change on the blue and green water footprints of food consumption. We first compare the water consumption of the current diets with that of a scenario where dietary guidelines are followed. Then, we assess these footprints by applying four scenarios in which we gradually limit the amount of protein from animal products to 50%, 25%, 12.5% and finally 0% of the total protein intake. We find that the current water use at the global scale would be sufficient to secure a recommended diet and worldwide energy intake. Reducing the animal product contribution in the diet would decrease global green water consumption by 6%, 11%, 15% and 21% within the four applied scenarios, while for blue water, the reductions would be 4%, 6%, 9% and 14%. In Latin America, Europe, Central and Eastern Asia and Sub-Saharan Africa, diet change mainly reduces green water use, while in the Middle East region, North America, Australia and Oceania, both blue and green water footprints decrease considerably. At the same time, in South and Southeast Asia, diet change does not result in decreased water use. Our results show that reducing animal products in the human diet offers the potential to save water resources, up to the amount currently required to feed 1.8 billion additional people globally; however, our results show that the adjustments should be considered on a local level.

  11. Nanomanufacturing of gold nanoparticle superstructures from the "bottom-up"

    NASA Astrophysics Data System (ADS)

    Rao, Tingling

    Gold nanoparticles that can generate surface plasmons under appropriate conditions have attracted significant interest for their potential in optics, photonics, data storage and biological sensors. Developing high fidelity fabrication methods that yield gold nanoparticles with well-defined size, shape, composition and self-assembly allows manipulation of surface plasmonic properties for novel applications as well as revealing new aspects of the underlying science. This dissertation demonstrates multiple techniques that describe cost-effective bottom-up" fabrication methods that yield gold nano-superstructures. In my initial work, I outline the solution conditions for fabricating Janus nanoparticles composed of one gold nanoparticle per micelle. Poly(ethylene oxide)-b-polystyrene (PEO-b-PS) was synthesized and processed into spherical micelles, which served as the template to induce gold nanoparticles growth within the PEO corona in situ. Organic-inorganic hybrid nanoparticle formation was controlled kinetically by manipulating the concentration of both the micelle and reducing agent (HEPES). We also found that under certain condition, PEO-b-PS yielded micelles with pearl-like morphology, which possessed concentrated PEO domains at the interface between two adjacent PS cores. Careful manipulation of reaction conditions afforded gold nanoparticles that grew from the core-shell interface to form 1-dimensional (1-D) periodical gold nanoparticle chains. Based on similar principles, gold-gold dimers were synthesized by growing a second gold nanoparticle from a gold nanoparticle template surface-functionalized with PEO ligands. Gold dimers fabricated with this method exhibited strong enhancement properties via surface-enhanced Raman scattering (SERS). Instead of kinetic control, the number of newly grown gold nanoparticles on each particle template heavily relied on the PEO density on the nanoparticle template. As the size of the particle template increased from 10 nm to

  12. 10. BUOY DECK, NEAR PILOT HOUSE SUPERSTRUCTURE, LOOKING TOWARDS FOCASTLE ...

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

    10. BUOY DECK, NEAR PILOT HOUSE SUPERSTRUCTURE, LOOKING TOWARDS FOCASTLE DECK, SHOWING MOST OF BOOM. - U.S. Coast Guard Cutter WHITE LUPINE, U.S. Coast Guard Station Rockland, east end of Tillson Avenue, Rockland, Knox County, ME

  13. 10. BUOY DECK, NEAR PILOT HOUSE SUPERSTRUCTURE, LOOKING TOWARDS FOCASTLE ...

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

    10. BUOY DECK, NEAR PILOT HOUSE SUPERSTRUCTURE, LOOKING TOWARDS FOCASTLE DECK. - U.S. Coast Guard Cutter WHITE HEATH, USGS Integrated Support Command Boston, 427 Commercial Street, Boston, Suffolk County, MA

  14. 12. BOOM, FROM SUPERSTRUCTURE DECK (ABOVE WINCH ROOM), LOOKING TOWARDS ...

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

    12. BOOM, FROM SUPERSTRUCTURE DECK (ABOVE WINCH ROOM), LOOKING TOWARDS BOW. - U.S. Coast Guard Cutter WHITE HEATH, USGS Integrated Support Command Boston, 427 Commercial Street, Boston, Suffolk County, MA

  15. 13. DETAIL OF BOOM'S GEARED WHEEL, FROM SUPERSTRUCTURE DECK (ABOVE ...

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

    13. DETAIL OF BOOM'S GEARED WHEEL, FROM SUPERSTRUCTURE DECK (ABOVE WINCH ROOM), FLYBRIDGE IS AT LEFT. - U.S. Coast Guard Cutter WHITE HEATH, USGS Integrated Support Command Boston, 427 Commercial Street, Boston, Suffolk County, MA

  16. 4. VIEW OF PART OF THE SUPERSTRUCTURE OF THE B ...

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

    4. VIEW OF PART OF THE SUPERSTRUCTURE OF THE B & O RAILROAD'S BASCULE BRIDGE, LOOKING SOUTH - Baltimore & Ohio Railroad, Chicago Terminal Railroad, South Branch of Chicago River Bridge, Spanning South Branch of Chicago River, Chicago, Cook County, IL

  17. 3. VIEW OF PART OF THE SUPERSTRUCTURE OF THE ST. ...

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

    3. VIEW OF PART OF THE SUPERSTRUCTURE OF THE ST. CHARLES AIRLINE RAILROAD'S BASCULE BRIDGE, LOOKING SOUTHEAST - Baltimore & Ohio Railroad, Chicago Terminal Railroad, South Branch of Chicago River Bridge, Spanning South Branch of Chicago River, Chicago, Cook County, IL

  18. 8. SOUTH REAR, SUPERSTRUCTURE. Looking north from deck. Edwards ...

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

    8. SOUTH REAR, SUPERSTRUCTURE. Looking north from deck. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  19. 5. EAST SIDE, TEST STAND AND ITS SUPERSTRUCTURE. Edwards ...

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

    5. EAST SIDE, TEST STAND AND ITS SUPERSTRUCTURE. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  20. 1. BEGINNING OF RAILWAY SUPERSTRUCTURE IN PHILADELPHIA COUNTY. FACING EAST ...

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

    1. BEGINNING OF RAILWAY SUPERSTRUCTURE IN PHILADELPHIA COUNTY. FACING EAST DOWN MARKET STREET. - Market Street Elevated Railway, Market Street between Sixty-ninth & Forty-sixth Streets, Philadelphia, Philadelphia County, PA

  1. 4. END OF RAILWAY SUPERSTRUCTURE, WHERE IT CROSSES NORTH OVER ...

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

    4. END OF RAILWAY SUPERSTRUCTURE, WHERE IT CROSSES NORTH OVER MARKET STREET AND DESCENDS TO MEET SUBWAY AT 44TH STREET. - Market Street Elevated Railway, Market Street between Sixty-ninth & Forty-sixth Streets, Philadelphia, Philadelphia County, PA

  2. 23. VIEW, LOOKING EAST, SHOWING SUPERSTRUCTURE FROM TRACK LEVEL ...

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

    23. VIEW, LOOKING EAST, SHOWING SUPERSTRUCTURE FROM TRACK LEVEL - New York, New Haven & Hartford Railroad, Groton Bridge, Spanning Thames River between New London & Groton, New London, New London County, CT

  3. 18. VIEW TO NORTH OF UNDERSIDE OF SUPERSTRUCTURE AND MASONRY ...

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

    18. VIEW TO NORTH OF UNDERSIDE OF SUPERSTRUCTURE AND MASONRY WORK OF NORTH APPROACH ABUTMENT - Twenty-first Street Bridge, Spanning Railroad tracks at Twenty-first Street, Saint Louis, Independent City, MO

  4. Divacancy superstructures in thermoelectric calcium-doped sodium cobaltate

    NASA Astrophysics Data System (ADS)

    Porter, D. G.; Roger, M.; Gutmann, M. J.; Uthayakumar, S.; Prabhakaran, D.; Boothroyd, A. T.; Pandiyan, M. S.; Goff, J. P.

    2014-08-01

    We have grown single crystals of NaxCayCoO2 and determined their superstructures as a function of composition using neutron and x-ray diffraction. Inclusion of Ca2+ stabilizes a single superstructure across a wide range of temperatures and concentrations. The superstructure in the Na+ layers is based on arrays of divacancy clusters with Ca2+ ions occupying the central site, and it has an ideal concentration Na4/7Ca1/7CoO2. Previous measurements of the thermoelectric properties on this system are discussed in light of this superstructure. Na4/7Ca1/7CoO2 corresponds to the maximum in thermoelectric performance of this system.

  5. 19. VIEW TO SOUTH OF UNDERSIDE OF NORTH APPROACH SUPERSTRUCTURE ...

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

    19. VIEW TO SOUTH OF UNDERSIDE OF NORTH APPROACH SUPERSTRUCTURE SHOWING FLOOR SYSTEM OF PONY TRUSS SPANS - Twenty-first Street Bridge, Spanning Railroad tracks at Twenty-first Street, Saint Louis, Independent City, MO

  6. 20. VIEW TO SOUTH OF UNDERSIDE OF SUPERSTRUCTURE SHOWING FLOOR ...

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

    20. VIEW TO SOUTH OF UNDERSIDE OF SUPERSTRUCTURE SHOWING FLOOR SYSTEM OF 150-FOOT THROUGH PARKER TRUSS SPAN - Twenty-first Street Bridge, Spanning Railroad tracks at Twenty-first Street, Saint Louis, Independent City, MO

  7. The emergence of superstructural order in insulin amyloid fibrils upon multiple rounds of self-seeding.

    PubMed

    Surmacz-Chwedoruk, Weronika; Babenko, Viktoria; Dec, Robert; Szymczak, Piotr; Dzwolak, Wojciech

    2016-01-01

    Typically, elongation of an amyloid fibril entails passing conformational details of the mother seed to daughter generations of fibrils with high fidelity. There are, however, several factors that can potentially prevent such transgenerational structural imprinting from perpetuating, for example heterogeneity of mother seeds or so-called conformational switching. Here, we examine phenotypic persistence of bovine insulin amyloid ([BI]) upon multiple rounds of self-seeding under quiescent conditions. According to infrared spectroscopy, with the following passages of homologous seeding, daughter fibrils gradually depart from the mother seed's spectral characteristics. We note that this transgenerational structural drift in [BI] amyloid leads toward fibrils with infrared, chiroptical, and morphological traits similar to those of the superstructural variant of fibrils which normally forms upon strong agitation of insulin solutions. However, in contrast to agitation-induced insulin amyloid, the superstructural assemblies of daughter fibrils isolated through self-seeding are sonication-resistant. Our results suggest that formation of single amyloid fibrils is not a dead-end of the amyloidogenic self-assembly. Instead, the process appears to continue toward the self-assembly of higher-order structures although on longer time-scales. From this perspective, the fast agitation-induced aggregation of insulin appears to be a shortcut to amyloid superstructures whose formation under quiescent conditions is slow. PMID:27558445

  8. The emergence of superstructural order in insulin amyloid fibrils upon multiple rounds of self-seeding

    PubMed Central

    Surmacz-Chwedoruk, Weronika; Babenko, Viktoria; Dec, Robert; Szymczak, Piotr; Dzwolak, Wojciech

    2016-01-01

    Typically, elongation of an amyloid fibril entails passing conformational details of the mother seed to daughter generations of fibrils with high fidelity. There are, however, several factors that can potentially prevent such transgenerational structural imprinting from perpetuating, for example heterogeneity of mother seeds or so-called conformational switching. Here, we examine phenotypic persistence of bovine insulin amyloid ([BI]) upon multiple rounds of self-seeding under quiescent conditions. According to infrared spectroscopy, with the following passages of homologous seeding, daughter fibrils gradually depart from the mother seed’s spectral characteristics. We note that this transgenerational structural drift in [BI] amyloid leads toward fibrils with infrared, chiroptical, and morphological traits similar to those of the superstructural variant of fibrils which normally forms upon strong agitation of insulin solutions. However, in contrast to agitation-induced insulin amyloid, the superstructural assemblies of daughter fibrils isolated through self-seeding are sonication-resistant. Our results suggest that formation of single amyloid fibrils is not a dead-end of the amyloidogenic self-assembly. Instead, the process appears to continue toward the self-assembly of higher-order structures although on longer time-scales. From this perspective, the fast agitation-induced aggregation of insulin appears to be a shortcut to amyloid superstructures whose formation under quiescent conditions is slow. PMID:27558445

  9. Integral ceramic superstructure evaluation using time domain optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Sinescu, Cosmin; Bradu, Adrian; Topala, Florin I.; Negrutiu, Meda Lavinia; Duma, Virgil-Florin; Podoleanu, Adrian G.

    2014-02-01

    Optical Coherence Tomography (OCT) is a non-invasive low coherence interferometry technique that includes several technologies (and the corresponding devices and components), such as illumination and detection, interferometry, scanning, adaptive optics, microscopy and endoscopy. From its large area of applications, we consider in this paper a critical aspect in dentistry - to be investigated with a Time Domain (TD) OCT system. The clinical situation of an edentulous mandible is considered; it can be solved by inserting 2 to 6 implants. On these implants a mesostructure will be manufactured and on it a superstructure is needed. This superstructure can be integral ceramic; in this case materials defects could be trapped inside the ceramic layers and those defects could lead to fractures of the entire superstructure. In this paper we demonstrate that a TD-OCT imaging system has the potential to properly evaluate the presence of the defects inside the ceramic layers and those defects can be fixed before inserting the prosthesis inside the oral cavity. Three integral ceramic superstructures were developed by using a CAD/CAM technology. After the milling, the ceramic layers were applied on the core. All the three samples were evaluated by a TD-OCT system working at 1300 nm. For two of the superstructures evaluated, no defects were found in the most stressed areas. The third superstructure presented four ceramic defects in the mentioned areas. Because of those defects the superstructure may fracture. The integral ceramic prosthesis was send back to the dental laboratory to fix the problems related to the material defects found. Thus, TD-OCT proved to be a valuable method for diagnosing the ceramic defects inside the integral ceramic superstructures in order to prevent fractures at this level.

  10. Existence of spherically symmetric solutions for a reduced gravity two-and-a-half layer system

    NASA Astrophysics Data System (ADS)

    Yao, Lei; Li, Zilai; Wang, Wenjun

    2016-08-01

    In this paper, we consider the well-posedness of solutions to a reduced gravity two-and-a-half layer system in oceanic fluid dynamics. By constructing suitable approximate solutions and using the method of weak convergence, we obtain the global existence of weak solutions in two-dimensional exterior spatial domain, when the initial data are large and spherically symmetric.

  11. A highly sensitive non-enzymatic glucose sensor based on bimetallic Cu-Ag superstructures.

    PubMed

    Li, Hua; Guo, Chun-Yan; Xu, Cai-Ling

    2015-01-15

    Bimetallic Cu-Ag superstructures were successfully fabricated for the first time by using the natural leaves as reducing agent through a facile one-step hydrothermal process. Morphology, structure and composition of the Cu-Ag superstructures were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS) and inductively coupled plasma-optical emission spectroscopy (ICP-OES), respectively. The results reveal that the Cu-Ag superstructure is bimetallic nanocomposite constructed by nanoparticles with low Ag content and shows a rough surface and porous flexural algae-like microstructure. By using a three-dimensional nickel foam as the scaffold, a novel non-enzymatic glucose sensor based on Cu-Ag nanocomposites has been fabricated and applied to non-enzymatic glucose detection. The as-prepared Cu-Ag nanocomposites based glucose sensor displays distinctly enhanced electrocatalytic activity compared to those obtained with pure Cu nanomaterials prepared with a similar procedure, revealing a synergistic effect of the matrix Cu and the doped Ag. Cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy indicate that the Cu-Ag superstructures based glucose sensor displays a fascinating sensitivity up to 7745.7 μA mM(-1) cm(-2), outstanding detection limit of 0.08 μM and fast amperometric response (<2 s) for glucose detection. Furthermore, the sensor also exhibits significant selectivity, excellent stability and reproducibility, as well as attractive feasibility for real sample analysis. Because of its excellent electrochemical performance, low cost and easy preparation, this novel electrode material is a promising candidate in the development of non-enzymatic glucose sensor. PMID:25113052

  12. Audit of a road bridge superstructure using ground penetrating radar

    NASA Astrophysics Data System (ADS)

    Yelf, Richard; Carse, Alan

    2000-04-01

    This paper describes a new application of Ground Penetrating Radar (GPR) in non-destructively assessing the delivered quality of bridge superstructure beams. A case history is described where GPR was used to assess the quality of 180 prestressed concrete beams in relation to the requirements specified in the engineering design. The beams analyzed in this project represent a standard design used in Queensland where several large polystyrene blocks (called 'voids') are cast internally within the deck beams to reduce the mass of the beams. GPR was used effectively to determine the finished location of these voids within the beams and identify any defects associated with the movement of the voids during manufacture of the beams. It was concluded that at least 90% of the beams were out of tolerance due to significant void movement in a vertical direction and there were significant associated defects of air cavities within the concrete, thin top and bottom flanges and longitudinal soffit cracking. Predominantly the voids had moved downwards during the concrete placement process. The accuracy of the GPR survey was determined to be +/- 5 mm where good calibration was obtained and +/- 10 mm for the global set of results of 4860 measurement points.

  13. Metallic Ternary Telluride with Sphalerite Superstructure.

    PubMed

    Adhikary, Amit; Mohapatra, Sudip; Lee, Seng Huat; Hor, Yew San; Adhikari, Puja; Ching, Wai-Yim; Choudhury, Amitava

    2016-03-01

    A new ternary compound with composition Cu5Sn2Te7 has been synthesized using the stoichiometric reaction of Cu, Sn, and Te. The compound crystallizes in C2 space group with unit cell parameters of a = 13.549(2) Å, b = 6.0521(11) Å, c = 9.568(2) Å, and β = 98.121(2)°. Cu5Sn2Te7 is a superstructure of sphalerite and exhibits tetrahedral coordination of Cu, Sn, and Te atoms, containing a unique adamantane-like arrangement. The compound is formally mixed valent with a high electrical conductivity of 9.8 × 10(5) S m(-1) at 300 K and exhibits metallic behavior having p-type charge carriers as indicated from the positive Seebeck coefficient. Hall effect measurements further confirm holes as charge carriers with a carrier density of 1.39 × 10(21) cm(-3) and Hall mobility of 4.5 cm(2) V(-1) s(-1) at 300 K. The electronic band structure calculations indicate the presence of a finite density of states around the Fermi level and agree well with the p-type metallic conductivity. Band structure analysis suggests that the effective mass of the hole state is small and could be responsible for high electronic conductivity and Hall mobility. The high thermal conductivity of 15.1 W m(-1) K(-1) at 300 K coupled with the low Seebeck coefficient results in a poor thermoelectric figure of merit (ZT) for this compound. Theoretical calculations indicate that if Cu5Sn2Te7 is turned into a valence precise compound by substituting one Cu by a Zn, a semiconducting material, Cu4ZnSn2Te7, with a direct band gap of ∼ 0.5 eV can be obtained. PMID:26890202

  14. The solute permeability of thylakoid membranes is reduced by low concentrations of trehalose as a co-solute.

    PubMed

    Bakaltcheva, I; Williams, W P; Schmitt, J M; Hincha, D K

    1994-01-01

    The different efficiencies of sucrose and trehalose in protecting isolated spinach (Spinacia oleracea L.) thylakoids against freeze-thaw damage is quantitatively related to their ability to reduce the solute loading of the vesicles during freezing. In the present paper we show that this effect is based on a reduction of the solute permeability of the membranes. Permeability was measured with 14C-labeled glucose at temperatures between 0 and 10 degrees C. Glucose permeability was reduced by both sucrose and trehalose, with trehalose effective at much lower concentrations than sucrose. An analysis of the temperature dependence of glucose permeability in the presence and absence of trehalose revealed that a 50% reduction in permeability resulted from a 10% increase in activation energy and a 30% decrease in activation entropy. Using the fluorescence probe 1,6-diphenyl-1,3,5-hexatriene (DPH), we found that the reduced permeability of the membranes in the presence of trehalose was unaccompanied by a reduction in lipid fluidity. This also excluded the possibility of a solute-induced liquid crystalline to gel phase transition. A reduced partitioning of the hydrophobicity-sensitive dye merocyanine 540 into thylakoids and into membranes containing 50% digalactosyldiacylglycerol in the presence of trehalose as compared to sucrose and glucose showed that the lipid headgroup region of these membranes became less accessible for solutes. No significant difference in merocyanine partitioning in the presence of trehalose as compared to sucrose or glucose was apparent when monogalactosyldiacylglycerol dispersions or phosphatidylcholine vesicles were investigated. PMID:8305457

  15. Existence of global weak solution for a reduced gravity two and a half layer model

    SciTech Connect

    Guo, Zhenhua Li, Zilai Yao, Lei

    2013-12-15

    We investigate the existence of global weak solution to a reduced gravity two and a half layer model in one-dimensional bounded spatial domain or periodic domain. Also, we show that any possible vacuum state has to vanish within finite time, then the weak solution becomes a unique strong one.

  16. A superstructure-based optimal synthesis of PSA cycles for post-combustion CO2 capture

    SciTech Connect

    Agarwal, A.; Biegler, L.; Zitney, S.

    2010-07-01

    Recent developments have shown pressure/vacuum swing adsorption (PSA/VSA) to be a promising option to effectively capture CO2 from flue gas streams. In most commercial PSA cycles, the weakly adsorbed component in the mixture is the desired product, and enriching the strongly adsorbed CO2 is not a concern. On the other hand, it is necessary to concentrate CO2 to high purity to reduce CO2 sequestration costs and minimize safety and environmental risks. Thus, it is necessary to develop PSA processes specifically targeted to obtain pure strongly adsorbed component. A multitude of PSA/VSA cycles have been developed in the literature for CO2 capture from feedstocks low in CO2 concentration. However, no systematic methodology has been suggested to develop, evaluate, and optimize PSA cycles for high purity CO2 capture. This study presents a systematic optimization-based formulation to synthesize novel PSA cycles for a given application. In particular, a novel PSA superstructure is presented to design optimal PSA cycle configurations and evaluate CO2 capture strategies. The superstructure is rich enough to predict a number of different PSA operating steps. The bed connections in the superstructure are governed by time-dependent control variables, which can be varied to realize most PSA operating steps. An optimal sequence of operating steps is achieved through the formulation of an optimal control problem with the partial differential and algebraic equations of the PSA system and the cyclic steady state condition. Large-scale optimization capabilities have enabled us to adopt a complete discretization methodology to solve the optimal control problem as a largescale nonlinear program, using the nonlinear optimization solver IPOPT. The superstructure approach is demonstrated for case studies related to post-combustion CO2 capture. In particular, optimal PSA cycles were synthesized, which maximize CO2 recovery for a given purity, and minimize overall power consumption. The

  17. Charge transfer and interface properties in inorganic superstructures and composites

    NASA Astrophysics Data System (ADS)

    Flyagina, I. S.; Petrov, A. A.; Pervov, V. S.

    2016-06-01

    The processes of charge transfer and electronic reconstruction at interfaces of inorganic superstructures and composites have not yet been adequately investigated. This review integrates and analyzes the results of theoretical and experimental studies of structural and electronic effects at interfaces of metal oxide or chalcogenide superstructures and composites. Charge transfer and, hence, change in interface properties compared to the properties of substructures are shown to be determined by the preparation method of composites and chemical nature of the superstructures, incommensurability of structural parameters and valence states of the constituent metals. The changes are maximal for nanoheterostructures, and the degree of change is related to electronic conductivity of substructures. The macroscopic properties of the composite materials depend on the amount of interfaces in their bulk. The bibliography includes 66 references.

  18. Origin of superstructures in (double) perovskite thin films

    SciTech Connect

    Shabadi, V. Major, M.; Komissinskiy, P.; Vafaee, M.; Radetinac, A.; Baghaie Yazdi, M.; Donner, W.; Alff, L.

    2014-09-21

    We have investigated the origin of superstructure peaks as observed by X-ray diffraction of multiferroic Bi(Fe{sub 0.5}Cr{sub 0.5})O{sub 3} thin films grown by pulsed laser deposition on single crystal SrTiO{sub 3} substrates. The photon energy dependence of the contrast between the atomic scattering factors of Fe and Cr is used to rule out a chemically ordered double perovskite Bi{sub 2}FeCrO{sub 6} (BFCO). Structural calculations suggest that the experimentally observed superstructure occurs due to unequal cation displacements along the pseudo-cubic [111] direction that mimic the unit cell of the chemically ordered compound. This result helps to clarify discrepancies in the correlations of structural and magnetic order reported for Bi{sub 2}FeCrO{sub 6}. The observation of a superstructure in itself is not a sufficient proof of chemical order in double perovskites.

  19. Superstructure for high current applications in superconducting linear accelerators

    DOEpatents

    Sekutowicz, Jacek; Kneisel, Peter

    2008-03-18

    A superstructure for accelerating charged particles at relativistic speeds. The superstructure consists of two weakly coupled multi-cell subunits equipped with HOM couplers. A beam pipe connects the subunits and an HOM damper is included at the entrance and the exit of each of the subunits. A coupling device feeds rf power into the subunits. The subunits are constructed of niobium and maintained at cryogenic temperatures. The length of the beam pipe between the subunits is selected to provide synchronism between particles and rf fields in both subunits.

  20. 46 CFR 45.111 - Strength of bulkheads at ends of superstructures.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Strength of bulkheads at ends of superstructures. 45.111... LOAD LINES Conditions of Assignment § 45.111 Strength of bulkheads at ends of superstructures. Bulkheads at ends of enclosed superstructures must have sufficient strength to withstand impact of...

  1. 46 CFR 45.111 - Strength of bulkheads at ends of superstructures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Strength of bulkheads at ends of superstructures. 45.111 Section 45.111 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES Conditions of Assignment § 45.111 Strength of bulkheads at ends of superstructures. Bulkheads at ends of enclosed superstructures...

  2. Ultrathin Laminar Ir Superstructure as Highly Efficient Oxygen Evolution Electrocatalyst in Broad pH Range.

    PubMed

    Pi, Yecan; Zhang, Nan; Guo, Shaojun; Guo, Jun; Huang, Xiaoqing

    2016-07-13

    Shape-controlled noble metal nanocrystals (NCs), such as Au, Ag, Pt, Pd, Ru, and Rh are of great success due to their new and enhanced properties and applications in chemical conversion, fuel cells, and sensors, but the realization of shape control of Ir NCs for achieving enhanced electrocatalysis remains a significant challenge. Herein, we report an efficient solution method for a new class of three-dimensional (3D) Ir superstructure that consists of ultrathin Ir nanosheets as subunits. Electrochemical studies show that it delivers the excellent electrocatalytic activity toward oxygen evolution reaction (OER) in alkaline condition with an onset potential at 1.43 V versus reversible hydrogen electrode (RHE) and a very low Tafel slope of 32.7 mV decade(-1). In particular, it even shows superior performance for OER in acidic solutions with the low onset overpotential of 1.45 V versus RHE and small Tafel slope of 40.8 mV decade(-1), which are much better than those of small Ir nanoparticles (NPs). The 3D Ir superstructures also exhibit good stability under acidic condition with the potential shift of less than 20 mV after 8 h i-t test. The present work highlights the importance of tuning 3D structures of Ir NCs for enhancing OER performance. PMID:27249544

  3. Closed-form solution for loop transfer recovery via reduced-order observers

    NASA Technical Reports Server (NTRS)

    Bacon, Barton J.

    1989-01-01

    A well-known property of the reduced-order observer is exploited to obtain the controller solution of the loop transfer recovery problem. In that problem, the controller is sought that generates some desired loop shape at the plant's input or output channels. Past approaches to this problem have typically yielded controllers generating loop shapes that only converge pointwise to the desired loop shape. In the proposed approach, however, the solution (at the input) is obtained directly when the plant's first Markov parameter is full rank. In the more general case when the plant's first Markov parameter is not full rank, the solution is obtained in an analogous manner by appending a special set of input and output signals to the original set. A dual form of the reduced-order observer is shown to yield the LTR solution at the output channel.

  4. 12. BOOM, FROM SUPERSTRUCTURE DECK (ABOVE WINCH ROOM), SHOWING DETAIL ...

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

    12. BOOM, FROM SUPERSTRUCTURE DECK (ABOVE WINCH ROOM), SHOWING DETAIL OF GEARED WHEEL OF BOOM, FLYBRIDGE AT LEFT. - U.S. Coast Guard Cutter WHITE LUPINE, U.S. Coast Guard Station Rockland, east end of Tillson Avenue, Rockland, Knox County, ME

  5. 15. SUPERSTRUCTURE PLANS, ELEVATION AND DETAILS, SHEET 4 OF 117, ...

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

    15. SUPERSTRUCTURE PLANS, ELEVATION AND DETAILS, SHEET 4 OF 117, 1920. - Sacramento River Water Treatment Plant Intake Pier & Access Bridge, Spanning Sacramento River approximately 175 feet west of eastern levee on river; roughly .5 mile downstream from confluence of Sacramento & American Rivers, Sacramento, Sacramento County, CA

  6. 18. CROWS NEST ATOP SUPERSTRUCTURE. Looking up from northeast corner ...

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

    18. CROWS NEST ATOP SUPERSTRUCTURE. Looking up from northeast corner of run line deck. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  7. 2. NORTH FRONT, FROM SUPERSTRUCTURE TO FLAME DEFLECTOR. Looking south ...

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

    2. NORTH FRONT, FROM SUPERSTRUCTURE TO FLAME DEFLECTOR. Looking south southwest from Observation Post No. 1 (Building 8767). - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  8. Detail of west span showing connection of superstructure to granite ...

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

    Detail of west span showing connection of superstructure to granite pier at low tide. Photograph articulates subdeck support members. View southeast - New York, New Haven & Hartford Railroad, Fort Point Channel Rolling Lift Bridge, Spanning Fort Point Channel, Boston, Suffolk County, MA

  9. Looking northeast from Test Stand 'A' superstructure towards Test Stand ...

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

    Looking northeast from Test Stand 'A' superstructure towards Test Stand 'D' tower (4223/E-24, left background), Test Stand 'C' tower (4217/E-18, center), and Test Stand 'B' (4215/E-16, right foreground). - Jet Propulsion Laboratory Edwards Facility, Edwards Air Force Base, Boron, Kern County, CA

  10. 2. DETAIL OF BUILDER'S PLATE: 'SUPERSTRUCTURE BUILT BY STROBEL STEEL ...

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

    2. DETAIL OF BUILDER'S PLATE: 'SUPERSTRUCTURE BUILT BY STROBEL STEEL CONSTRUCTION CO., CHICAGO, ILL., 1913, SUBSTRUCTURE BUILT BY FITZSIMONS & CONNELL D&D CO., CHICAGO, ILL.' - Chicago River Bascule Bridge, Grand Avenue, Spanning North Branch Chicago River at Grand Avenue, Chicago, Cook County, IL

  11. 19. TRAVELING CRANE ATOP SUPERSTRUCTURE, FROM RUN LINE DECK. Looking ...

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

    19. TRAVELING CRANE ATOP SUPERSTRUCTURE, FROM RUN LINE DECK. Looking up to north northeast. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  12. 3. DETAIL OF NORTH FRONT AND WEST SIDE, WITH SUPERSTRUCTURE, ...

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

    3. DETAIL OF NORTH FRONT AND WEST SIDE, WITH SUPERSTRUCTURE, FROM NEAR OBSERVATION POST NO. 3. Looking south southeast from below. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  13. View of riveted joint on tower support superstructure of Tensaw ...

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

    View of riveted joint on tower support superstructure of Tensaw River Bridge truss No. 2, looking southwest, showing deflector sheaves, roller and complex joint construction - Tensaw River Lift Bridge, Spanning Tensaw River at U.S. Highway 90, Mobile, Mobile County, AL

  14. View of riveted joint on tower support superstructure of Tensaw ...

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

    View of riveted joint on tower support superstructure of Tensaw River Bridge truss No. 2, looking northeast, showing deflector sheaves, roller and complex joint construction - Tensaw River Lift Bridge, Spanning Tensaw River at U.S. Highway 90, Mobile, Mobile County, AL

  15. 6. SOUTH SIDE AND UNDERSIDE OF SUPERSTRUCTURE, FACING NORTH ON ...

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

    6. SOUTH SIDE AND UNDERSIDE OF SUPERSTRUCTURE, FACING NORTH ON MARKET STREET BETWEEN 45TH AND 46TH STREETS. DETAIL OF BEAMS AND GIRDERS. - Market Street Elevated Railway, Market Street between Sixty-ninth & Forty-sixth Streets, Philadelphia, Philadelphia County, PA

  16. 12. A CLOSE UP VIEW OF THE IRON SUPERSTRUCTURE OF ...

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

    12. A CLOSE UP VIEW OF THE IRON SUPERSTRUCTURE OF THIS CAMELBACK TRUSS BRIDGE. THIS PHOTO SHOWS A DETAIL OF THE LATTICE WORK, AND AN INTERESTING CURVED BRACE MEMBER. - Freedom Bridge, Spanning West Fork of White River at County Road 590 South, Freedom, Owen County, IN

  17. 11. VIEW SHOWING THE SUPERSTRUCTURE OF THE SHED ROOF (REMOVED ...

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

    11. VIEW SHOWING THE SUPERSTRUCTURE OF THE SHED ROOF (REMOVED AUTUMN OF 1996) PROTECTING THE PRESENT INTAKE GATES- AND RAKE-LIFTING MECHANISMS AND THE TRASH RACKS (LOWER FOREGROUND), LOOKING NORTH. - Washington Water Power Company Post Falls Power Plant, Middle Channel Powerhouse & Dam, West of intersection of Spokane & Fourth Streets, Post Falls, Kootenai County, ID

  18. Separation and concentration of hazardous metals from aqueous solutions using sulfate-reducing bacteria

    SciTech Connect

    Apel, W.A.; Wiebe, M.R.; Dugan, P.R.

    1990-01-01

    The removal of metals from aqueous solutions using sulfate-reducing bacteria was investigated. The sulfate-reducing bacteria utilized consisted of a consortium isolated from oil well brine. The consortium was capable of using lactate as a carbon and energy source and producing significant quantities of sulfide which reacted with solubilized metals to form insoluble metal sulfides. After formation, the metal sulfides were removed from solution via filtration. A variety of solubilized metals including lead, cadmium, cobalt, copper, iron, and chromium were removed from solution using sulfate-reducing bacteria. Removal efficiencies varied from metal to metal with lead exhibiting the highest levels of removal and chromium the lowest. 13 refs., 9 figs.

  19. Impact of a Reducing Agent on the Dynamic Surface Properties of Lysozyme Solutions.

    PubMed

    Tihonov, Michael M; Kim, Viktoria V; Noskov, Boris A

    2016-05-01

    Disulfide bond shuffling in the presence of the reducing agents dithiothreitol (DTT) or β-mercaptoethanol (BME) strongly affects the surface properties of lysozyme solutions. The addition of 0.32 mM DTT substantially alters the kinetic dependencies of the dynamic surface elasticity and surface tension relative to those of pure protein solutions. The significant increase in the dynamic surface elasticity likely relates to the cross-linking between lysozyme molecules and the formation of a dense layer of protein globules stabilized by intermolecular disulfide bonds at the liquid/gas interface. This effect differs from the previously described influence of chaotropic denaturants, such as guanidine hydrochloride (GuHCl) and urea, on the surface properties of lysozyme solutions. If both chaotropic and reducing agents are added to protein solutions simultaneously, their effects become superimposed. In the case of mixed lysozyme/GuHCl/DTT solutions, the dynamic surface elasticity near equilibrium decreases as the GuHCl concentration increases because of the gradual loosening of the cross-linked layer of protein globules but remains much higher than that of lysozyme/GuHCl solutions. PMID:27086995

  20. Methods for reducing the divergence of lamp-excited rhodamine 6G solution lasers

    SciTech Connect

    Smirnov, V.S.

    1980-11-01

    Different methods for reducing the divergence of rhodamine 6G solution lasers with lamp pumping are studied experimentally. A reduction of divergence to 2--4 mrad is achieved. It is shown that some methods provide such low divergence for comparatively low losses of lasing energy.

  1. Spray washing carcasses with alkaline solutions of lauric acid to reduce bacterial contamination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ability of lauric acid (LA)-potassium hydroxide (KOH) solutions to reduce carcass bacterial contamination was examined. Skin of carcasses was inoculated with a cecal paste containing antibiotic resistant strains of Escherichia coli, Salmonella Typhimirum, and Campylobacter coli. In one trial, in...

  2. EVIDENCE OF QUASI-LINEAR SUPER-STRUCTURES IN THE COSMIC MICROWAVE BACKGROUND AND GALAXY DISTRIBUTION

    SciTech Connect

    Inoue, Kaiki Taro; Sakai, Nobuyuki; Tomita, Kenji

    2010-11-20

    Recent measurements of hot and cold spots on the cosmic microwave background (CMB) sky suggest the presence of super-structures on (>100 h {sup -1} Mpc) scales. We develop a new formalism to estimate the expected amplitude of temperature fluctuations due to the integrated Sachs-Wolfe (ISW) effect from prominent quasi-linear structures. Applying the developed tools to the observed ISW signals from voids and clusters in catalogs of galaxies at redshifts z < 1, we find that they indeed imply a presence of quasi-linear super-structures with a comoving radius of 100 {approx} 300 h {sup -1} Mpc and a density contrast |{delta}| {approx} O(0.1). We also find that the observed ISW signals are at odds with the concordant {Lambda} cold dark matter model that predicts Gaussian primordial perturbations at {approx}>3{sigma} level. We confirm that the mean temperature around the CMB cold spot in the southern Galactic hemisphere filtered by a compensating top-hat filter deviates from the mean value at {approx}3{sigma} level, implying that a quasi-linear supervoid or an underdensity region surrounded by a massive wall may reside at low redshifts z < 0.3 and the actual angular size (16{sup 0}-17{sup 0}) may be larger than the apparent size (4{sup 0}-10{sup 0}) discussed in literature. Possible solutions are briefly discussed.

  3. Solution of reduced graphene oxide synthesized from coconut shells and its optical properties

    NASA Astrophysics Data System (ADS)

    Mas'udah, Kusuma Wardhani; Nugraha, I. Made Ananta; Abidin, Saiful; Mufid, Ali; Astuti, Fahmi; Darminto

    2016-04-01

    Reduced graphene oxide (r-GO)powder has been prepared from coconut shells by carbonization process at 400°C for 3, 4 and 5 hours.Theresulted sample mass was reduced to be 60% relativelycompared to the starting material. The longer heating duration has also led to the rGO with reduced crystalinity according to the X-ray diffractometry data and TEM. The rGO solution was prepared by adding powders of 5, 10 and 15 grams into 50 ml destiled water and then centrifused at 6000 rpm for 30 minutes.The resulted solutions were seen to be varied form clear transparant, light and dark yellow to black. Measurement using particle size analyser shows that the individual rGO particles tends to be agglomerating each others to form bigger size clustering, manifested by the observed bigger size particles for the increasing amount of soluted rGO powders in water.The varying UV-visible spectra of these rGO solutions together with their optical bandgaps will also be discussed in this study.

  4. Rationalization and prediction of rare earth selenide superstructures

    SciTech Connect

    Lee, S.; Foran, B. )

    1994-01-12

    We apply second-moment scaled Huckel theory with inclusion of ionic terms to rationalize or predict superstructures found in elemental selenium, LnQ[sub 2] (Ln = La, Ce; Q = S, Se), Ln[sub 10]Se[sub 19] (Ln = La, Ce, Pr, Nd, Sm), and RbDy[sub 3]Se[sub 8]. All these structures contain distortions of square lattices of chalcogen atoms. In the case of Ln[sub 10]Se[sub 19] and RbDy[sub 3]Se[sub g] these lattice distortions are coupled to ordered defects in the chalcogen square lattice. On the basis of our energy calculations we propose eight ground state RbDy[sub 3]Se[sub 8] superstructure patterns among the 5 x 10[sup 5] possible alternatives. Finally we explain the results of our calculations using HOMO-LUMO and Madelung energy arguments. 23 refs., 14 figs., 4 tabs.

  5. 16. PORT SIDE OF DECK OF SUPERSTRUCTURE WITH STEPS UP ...

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

    16. PORT SIDE OF DECK OF SUPERSTRUCTURE WITH STEPS UP TO PORT SIDE OF FLYBRIDGE (IMAGE 15) AT LEFT, STRUCTURE TO RIGHT OF STAIRS IS PILOT HOUSE, STRUCTURE TO RIGHT AND REAR OF PILOT HOUSE IS CO'S STATEROOM (CAPTAIN'S QUARTERS). TWO WINDOWS TO RIGHT HAVE WOODEN FRAMES. - U.S. Coast Guard Cutter WHITE HEATH, USGS Integrated Support Command Boston, 427 Commercial Street, Boston, Suffolk County, MA

  6. Mechanisms of reduced solute diffusivity at nanoconfined solid-liquid interface

    NASA Astrophysics Data System (ADS)

    Mahadevan, T.; Kojic, M.; Ferrari, M.; Ziemys, A.

    2013-06-01

    We report results from molecular simulations that reveal the causes of reduced diffusivity at solid-liquid interfaces in the presence of nanoscale confinement. The diffusion of a 2 M glucose solution was simulated inside a 10 nm silica channel together with the calculated thermodynamic properties of diffusion. A strong energy-entropy compensation mechanism was found at the interface with a free energy minimum of -0.6 kcal/mol. Using the Eyring equation the average jump length was reduced by 15% at interface. The complete loss of solute diffusivity at silica surface was explained by the substantial loss of the probability of productive displacements. The results suggested that glucose molecule diffusivity close to the surface might be related to a stiffer cage of the hydration shell, which affects the probability of cage breaking. These results help in understanding of diffusion mechanisms at interface and predicting mass transport in nanoconfinement for engineering and biomedical applications.

  7. Fabrication of luminescent Eu{sub 2}O{sub 3} superstructures.

    SciTech Connect

    Pol, V. G.; Calderon-Moreno, J. M.; Chemical Sciences and Engineering Division; Inst. of Physical Chemistry

    2010-01-01

    This Letter demonstrates a solvent-free efficient synthesis process to prepare self-assembled two-dimensional Eu{sub 2}O{sub 3} luminescent nanoplates to yield a superstructure. In the first step, Eu{sub 2}O{sub 3}CO{sub 3} superstructures are fabricated by the thermolysis [700C] of a single precursor, europium acetate, in a closed reactor under autogenic pressure. The as-prepared Eu{sub 2}O{sub 3}CO{sub 3} superstructures are further heated in air to 750C to facilitate the fabrication of Eu{sub 2}O{sub 3} superstructures. A systematic morphological, structural, and compositional characterization of Eu{sub 2}O{sub 3} superstructures is carried out. The photoluminescent properties and mechanism for the strong red emission of the photoexcited Eu{sub 2}O{sub 3} superstructures is proposed.

  8. Systematic approach to obtain analytic solutions of quasi steady state species in reduced mechanisms.

    PubMed

    Lu, Tianfeng; Law, Chung K

    2006-12-14

    A systematic approach was developed to obtain analytic solutions for the concentrations of the quasi steady state (QSS) species in reduced mechanisms. The nonlinear algebraic equations for the QSS species concentrations were first approximated by a set of linear equations, and the linearized quasi steady state approximations (LQSSA) were then analytically solved with a directed graph, namely a QSSG, which was abstracted from the inter-dependence of QSS species. To obtain analytic solutions of high computational efficiency, the groups of strongly connected QSS species were first identified in the QSSG. The inter group couplings were then resolved by a topological sort, and the inner group couplings were solved with variable elimination by substitution. An efficient algorithm was developed to identify a near-optimal sequence for the variable elimination process. The proposed LQSSA-QSSG method was applied to generate a 16-step reduced mechanism for ethylene/air, and good accuracy and high efficiency were observed in simulations of auto-ignition and perfectly stirred reactors with the reduced mechanism. PMID:17149834

  9. Kinetics and mechanism of degradation of dichlorvos in aqueous solutions containing reduced sulfur species.

    PubMed

    Gan, Qiu; Singh, Raphael M; Wu, Tong; Jans, Urs

    2006-09-15

    Reactions of dichlorvos with five reduced sulfur species (hydrogen sulfide, bisulfide, thiosulfate, thiophenol, and thiophenolate) were examined in well-defined anoxic aqueous solutions to investigate their role in its degradation. Reactions were monitored at varying concentrations of reduced sulfur species over pH range to obtain the second-order reaction rate constants. Experiments at 25 degrees C demonstrated that degradation of dichlorvos promoted by bisufide, thiosulfate, and thiophenolate were of much greater importance than hydrolysis under the experimental conditions in our study. In contrast, hydrogen sulfide and thiophenol were not effective in the degradation of dichlorvos. The activation parameters of the reaction of dichlorvos with bisulfide, thiosulfate, and thiophenolate were also determined from the measured second-order rate constants over a temperature range of 12-50 degrees C. The relative reactivity of the reduced sulfur species decreases in the following order: PhS- > HS- approximately equal to S2O3(2-). When the second-order rate constants at 25 degrees C are multiplied by the environmentally relevant concentration of the reduced sulfur species, predicted half-lives of dichlorvos ranged from hours to days. The results indicated that reduced sulfur species could play a very important role in the chemical fate of dichlorvos in coastal marine environments. PMID:17007131

  10. 7. VIEW NORTHWEST OF 'ISLAND' (TOWER OR SUPERSTRUCTURE) ON THE ...

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

    7. VIEW NORTHWEST OF 'ISLAND' (TOWER OR SUPERSTRUCTURE) ON THE DECK OF THE AIRCRAFT CARRIER JOHN F. KENNEDY. WHEN THE PHOTOGRAPH WAS TAKEN IN SEPTEMBER 1994, THE KENNEDY WAS IN DRY-DOCK FOR REFURBISHMENT UNDER THE 'SERVICE LIFE EXTENSION PROGRAM (SLEP). THE 'ISLAND' HOUSES THE SHIP'S BRIDGE AND A CONTROL CENTER FOR AIRCRAFT OPERATIONS. EXTENSIVE SCAFFOLDING WAS REQUIRED TO ALLOW FULL ACCESS TO THE PAINTERS AND TECHNICIANS WORKING HERE. - Naval Base Philadelphia-Philadelphia Naval Shipyard, Dry Dock No. 5, League Island, Philadelphia, Philadelphia County, PA

  11. 46 CFR 45.59 - Definitions for superstructure corrections.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Definitions for superstructure corrections. 45.59... 840 0.2448 850 0.2420 860 0.2392 870 0.2364 880 0.2336 890 0.2308 900 0.2280 910 0.2252 920 0.2224 930....89063 180 9.19625 190 9.42188 200 9.68750 210 9.95313 220 10.21875 230 10.48438 240 10.75000 250...

  12. 46 CFR 45.59 - Definitions for superstructure corrections.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Definitions for superstructure corrections. 45.59... 840 0.2448 850 0.2420 860 0.2392 870 0.2364 880 0.2336 890 0.2308 900 0.2280 910 0.2252 920 0.2224 930....89063 180 9.19625 190 9.42188 200 9.68750 210 9.95313 220 10.21875 230 10.48438 240 10.75000 250...

  13. Investigation of the required length for fully developed pipe flow with drag-reducing polymer solutions

    NASA Astrophysics Data System (ADS)

    Farsiani, Yasaman; Elbing, Brian

    2015-11-01

    Adding trace amounts of long chain polymers into a liquid flow is known to reduce skin friction drag by up to 80%. While polymer drag reduction (PDR) has been successfully implemented in internal flows, diffusion and degradation have limited its external flow applications. A weakness in many previous PDR studies is that there was no characterization of the polymer being injected into the turbulent boundary layer, which can be accomplished by testing a sample in a pressure-drop tube. An implicit assumption in polymer characterization is that the flow is fully developed at the differential pressure measurement. While available data in the literature shows that the entry length to achieve fully developed flow increases with polymeric solutions, it is unclear how long is required to achieve fully developed flow for non-Newtonian turbulent flows. In the present study, the pressure-drop is measured across a 1.05 meter length section of a 1.04 cm inner diameter pipe. Differential pressure is measured with a pressure transducer for different entry lengths, flow and polymer solution properties. This presentation will present preliminary data on the required entrance length as well as characterization of polymer solution an estimate of the mean molecular weight.

  14. Soil solution response to experimentally reduced acid deposition in a forest ecosystem

    SciTech Connect

    Alewell, C.; Matzner, E.; Bredemeier, M.; Blanch, K.

    1997-05-01

    In order to measure and predict reversibility of soil solution acidification under experimentally reduced acid input, a manipulation study with artificial {open_quote}preindustrial{close_quote} throughfall was established. A roof was installed underneath the canopy in a Norway Spruce stand of the German Soiling area. Water failing onto the roof was adjusted to clean rain concentrations before redistribution. Soil solutions were collected with suction cup lysimeters at various depths and were analyzed for major ions. The response of soil solution chemistry in the upper soil (10 cm depth) to a reduction of N, SO{sub 4}, and H input was rapid. While NO{sub 3} concentration in deeper soil layers reached input levels after 2 yr of treatment, SO{sub 4} concentration in the seepage water at 1 m depth remained high relative to the reduced input due to a release of formerly stored S from the soil. Aluminum concentration followed a similar pattern as the SO{sub 4} concentrations. The ion concentrations in soil leachate were predicted reasonably well using the MAGIC model with the measured SO{sub 4} sorption isotherms and the throughfall fluxes as model input Although the parameters of the Langmuir isotherm had no significant influence to the prediction of SO{sub 4} concentration in the upper soil layer, they were crucial for the prediction of SO{sub 4} dynamics in deeper soil layers. The model predicted that the reversibility of soil acidification at the Soiling area is delayed for decades due to the release of soil SO{sub 4}. 38 refs., 5 figs., 4 tabs.

  15. Magnetic-Field-Assisted Assembly of Anisotropic Superstructures by Iron Oxide Nanoparticles and Their Enhanced Magnetism.

    PubMed

    Jiang, Chengpeng; Leung, Chi Wah; Pong, Philip W T

    2016-12-01

    Magnetic nanoparticle superstructures with controlled magnetic alignment and desired structural anisotropy hold promise for applications in data storage and energy storage. Assembly of monodisperse magnetic nanoparticles under a magnetic field could lead to highly ordered superstructures, providing distinctive magnetic properties. In this work, a low-cost fabrication technique was demonstrated to assemble sub-20-nm iron oxide nanoparticles into crystalline superstructures under an in-plane magnetic field. The gradient of the applied magnetic field contributes to the anisotropic formation of micron-sized superstructures. The magnitude of the applied magnetic field promotes the alignment of magnetic moments of the nanoparticles. The strong dipole-dipole interactions between the neighboring nanoparticles lead to a close-packed pattern as an energetically favorable configuration. Rod-shaped and spindle-shaped superstructures with uniform size and controlled spacing were obtained using spherical and polyhedral nanoparticles, respectively. The arrangement and alignment of the superstructures can be tuned by changing the experimental conditions. The two types of superstructures both show enhancement of coercivity and saturation magnetization along the applied field direction, which is presumably associated with the magnetic anisotropy and magnetic dipole interactions of the constituent nanoparticles and the increased shape anisotropy of the superstructures. Our results show that the magnetic-field-assisted assembly technique could be used for fabricating nanomaterial-based structures with controlled geometric dimensions and enhanced magnetic properties for magnetic and energy storage applications. PMID:27067737

  16. 46 CFR 42.20-60 - Deduction for superstructures and trunks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...; deductions at intermediate lengths shall be obtained by linear interpolation. (b) Where the total effective... 100 1 Percentages at intermediate lengths of superstructures and trunks shall be obtained by linear... intermediate lengths of superstructures and trunks shall be obtained by linear interpolation. (c) For...

  17. 40 CFR 745.228 - Accreditation of training programs: public and commercial buildings, bridges and superstructures...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Accreditation of training programs: public and commercial buildings, bridges and superstructures. 745.228 Section 745.228 Protection of... of training programs: public and commercial buildings, bridges and superstructures....

  18. 40 CFR 745.228 - Accreditation of training programs: public and commercial buildings, bridges and superstructures...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Accreditation of training programs: public and commercial buildings, bridges and superstructures. 745.228 Section 745.228 Protection of... of training programs: public and commercial buildings, bridges and superstructures....

  19. 40 CFR 745.228 - Accreditation of training programs: public and commercial buildings, bridges and superstructures...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Accreditation of training programs: public and commercial buildings, bridges and superstructures. 745.228 Section 745.228 Protection of... of training programs: public and commercial buildings, bridges and superstructures....

  20. 40 CFR 745.228 - Accreditation of training programs: public and commercial buildings, bridges and superstructures...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Accreditation of training programs: public and commercial buildings, bridges and superstructures. 745.228 Section 745.228 Protection of... of training programs: public and commercial buildings, bridges and superstructures....

  1. 40 CFR 745.228 - Accreditation of training programs: public and commercial buildings, bridges and superstructures...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Accreditation of training programs: public and commercial buildings, bridges and superstructures. 745.228 Section 745.228 Protection of... of training programs: public and commercial buildings, bridges and superstructures....

  2. 46 CFR 108.133 - Hull superstructure, structural bulkheads, decks, and deckhouses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Hull superstructure, structural bulkheads, decks, and deckhouses. 108.133 Section 108.133 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A... Protection § 108.133 Hull superstructure, structural bulkheads, decks, and deckhouses. Each...

  3. 46 CFR 108.133 - Hull superstructure, structural bulkheads, decks, and deckhouses.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Hull superstructure, structural bulkheads, decks, and deckhouses. 108.133 Section 108.133 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A... Protection § 108.133 Hull superstructure, structural bulkheads, decks, and deckhouses. Each...

  4. 46 CFR 108.133 - Hull superstructure, structural bulkheads, decks, and deckhouses.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Hull superstructure, structural bulkheads, decks, and deckhouses. 108.133 Section 108.133 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A... Protection § 108.133 Hull superstructure, structural bulkheads, decks, and deckhouses. Each...

  5. 46 CFR 108.133 - Hull superstructure, structural bulkheads, decks, and deckhouses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Hull superstructure, structural bulkheads, decks, and deckhouses. 108.133 Section 108.133 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A... Protection § 108.133 Hull superstructure, structural bulkheads, decks, and deckhouses. Each...

  6. 46 CFR 108.133 - Hull superstructure, structural bulkheads, decks, and deckhouses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Hull superstructure, structural bulkheads, decks, and deckhouses. 108.133 Section 108.133 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A... Protection § 108.133 Hull superstructure, structural bulkheads, decks, and deckhouses. Each...

  7. 46 CFR 45.113 - Access openings in bulkheads at ends of enclosed superstructures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Access openings in bulkheads at ends of enclosed superstructures. 45.113 Section 45.113 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES Conditions of Assignment § 45.113 Access openings in bulkheads at ends of enclosed superstructures. (a)...

  8. Magnetic-Field-Assisted Assembly of Anisotropic Superstructures by Iron Oxide Nanoparticles and Their Enhanced Magnetism

    NASA Astrophysics Data System (ADS)

    Jiang, Chengpeng; Leung, Chi Wah; Pong, Philip W. T.

    2016-04-01

    Magnetic nanoparticle superstructures with controlled magnetic alignment and desired structural anisotropy hold promise for applications in data storage and energy storage. Assembly of monodisperse magnetic nanoparticles under a magnetic field could lead to highly ordered superstructures, providing distinctive magnetic properties. In this work, a low-cost fabrication technique was demonstrated to assemble sub-20-nm iron oxide nanoparticles into crystalline superstructures under an in-plane magnetic field. The gradient of the applied magnetic field contributes to the anisotropic formation of micron-sized superstructures. The magnitude of the applied magnetic field promotes the alignment of magnetic moments of the nanoparticles. The strong dipole-dipole interactions between the neighboring nanoparticles lead to a close-packed pattern as an energetically favorable configuration. Rod-shaped and spindle-shaped superstructures with uniform size and controlled spacing were obtained using spherical and polyhedral nanoparticles, respectively. The arrangement and alignment of the superstructures can be tuned by changing the experimental conditions. The two types of superstructures both show enhancement of coercivity and saturation magnetization along the applied field direction, which is presumably associated with the magnetic anisotropy and magnetic dipole interactions of the constituent nanoparticles and the increased shape anisotropy of the superstructures. Our results show that the magnetic-field-assisted assembly technique could be used for fabricating nanomaterial-based structures with controlled geometric dimensions and enhanced magnetic properties for magnetic and energy storage applications.

  9. Structure of reduced DsbA from Escherichia coli in solution.

    PubMed

    Schirra, H J; Renner, C; Czisch, M; Huber-Wunderlich, M; Holak, T A; Glockshuber, R

    1998-05-01

    The three-dimensional structure of reduced DsbA from Escherichia coli in aqueous solution has been determined by nuclear magnetic resonance (NMR) spectroscopy and is compared with the crystal structure of oxidized DsbA [Guddat, L. W., Bardwell, J. C. A., Zander, T., and Martin, J. L. (1997) Protein Sci. 6, 1148-1156]. DsbA is a monomeric 21 kDa protein which consists of 189 residues and is required for disulfide bond formation in the periplasm of E. coli. On the basis of sequence-specific 1H NMR assignments, 1664 nuclear Overhauser enhancement distance constraints, 118 hydrogen bond distance constraints, and 293 dihedral angle constraints were obtained as the input for the structure calculations by simulated annealing with the program X-PLOR. The enzyme is made up of two domains. The catalytic domain has a thioredoxin-like fold with a five-stranded beta-sheet and three alpha-helices, and the second domain consists of four alpha-helices and is inserted into the thioredoxin motif. The active site between Cys30 and Cys33 is located at the N terminus of the first alpha-helix in the thioredoxin-like domain. The solution structure of reduced DsbA is rather similar to the crystal structure of the oxidized enzyme but exhibits a different relative orientation of both domains. In addition, the conformations of the active site and a loop between strand beta5 and helix alpha7 are slightly different. These structural differences may reflect important functional requirements in the reaction cycle of DsbA as they appear to facilitate the release of oxidized polypeptides from reduced DsbA. The extremely low pKa value of the nucleophilic active site thiol of Cys30 in reduced DsbA is most likely caused by its interactions with the dipole of the active site helix and the side chain of His32, as no other charged residues are located next to the sulfur atom of Cys30 in the solution structure. PMID:9572841

  10. Stacking faults and superstructures in a layered brownmillerite

    PubMed Central

    Krüger, H.; Stöber, S.; Welberry, T. R.; Withers, R. L.; Fitz Gerald, J. D.

    2011-01-01

    Single crystals of Ca4Fe2Mn0.5Ti0.5O9 have been synthesized using a flux method. The structural characterization using single-crystal X-ray diffraction revealed the space group Amma and unit-cell dimensions of a = 5.3510 (6), b = 26.669 (3), c = 5.4914 (6) Å. The structure is isotypic with Sr3NdFe3O9 [Barrier et al. (2005 ▸). Chem. Mater. 17, 6619–6623] and exhibits separated brownmillerite-type layers. One-dimensional diffuse scattering shows that the unit cell is doubled along c by alternating the intra-layer order of tetrahedral chains, causing stacking faults along the b direction. A computer simulation was performed, proving that the observed intensity variations along the diffuse scattering rods originates from two different local structures depending on the configuration of the tetrahedral chains. Selected-area electron diffraction experiments exhibit well ordered regions characterized by satellite reflections corresponding to two different superstructures. Both superstructures can be described using the superspace group A21/m(0βγ)0s, with γ = 0.5 and β ≃ 0.27 or β = 0. PMID:22101537

  11. Practical solutions for reducing container ships' waiting times at ports using simulation model

    NASA Astrophysics Data System (ADS)

    Sheikholeslami, Abdorreza; Ilati, Gholamreza; Yeganeh, Yones Eftekhari

    2013-12-01

    The main challenge for container ports is the planning required for berthing container ships while docked in port. Growth of containerization is creating problems for ports and container terminals as they reach their capacity limits of various resources which increasingly leads to traffic and port congestion. Good planning and management of container terminal operations reduces waiting time for liner ships. Reducing the waiting time improves the terminal's productivity and decreases the port difficulties. Two important keys to reducing waiting time with berth allocation are determining suitable access channel depths and increasing the number of berths which in this paper are studied and analyzed as practical solutions. Simulation based analysis is the only way to understand how various resources interact with each other and how they are affected in the berthing time of ships. We used the Enterprise Dynamics software to produce simulation models due to the complexity and nature of the problems. We further present case study for berth allocation simulation of the biggest container terminal in Iran and the optimum access channel depth and the number of berths are obtained from simulation results. The results show a significant reduction in the waiting time for container ships and can be useful for major functions in operations and development of container ship terminals.

  12. Improved thermal oxidation stability of solution-processable silver nanowire transparent electrode by reduced graphene oxide.

    PubMed

    Ahn, Yumi; Jeong, Youngjun; Lee, Youngu

    2012-12-01

    Solution-processable silver nanowire-reduced graphene oxide (AgNW-rGO) hybrid transparent electrode was prepared in order to replace conventional ITO transparent electrode. AgNW-rGO hybrid transparent electrode exhibited high optical transmittance and low sheet resistance, which is comparable to ITO transparent electrode. In addition, it was found that AgNW-rGO hybrid transparent electrode exhibited highly enhanced thermal oxidation and chemical stabilities due to excellent gas-barrier property of rGO passivation layer onto AgNW film. Furthermore, the organic solar cells with AgNW-rGO hybrid transparent electrode showed good photovoltaic behavior as much as solar cells with AgNW transparent electrode. It is expected that AgNW-rGO hybrid transparent electrode can be used as a key component in various optoelectronic application such as display panels, touch screen panels, and solar cells. PMID:23206541

  13. Solution-Processed Copper/Reduced-Graphene-Oxide Core/Shell Nanowire Transparent Conductors.

    PubMed

    Dou, Letian; Cui, Fan; Yu, Yi; Khanarian, Garo; Eaton, Samuel W; Yang, Qin; Resasco, Joaquin; Schildknecht, Christian; Schierle-Arndt, Kerstin; Yang, Peidong

    2016-02-23

    Copper nanowire (Cu NW) based transparent conductors are promising candidates to replace ITO (indium-tin-oxide) owing to the high electrical conductivity and low-cost of copper. However, the relatively low performance and poor stability of Cu NWs under ambient conditions limit the practical application of these devices. Here, we report a solution-based approach to wrap graphene oxide (GO) nanosheets on the surface of ultrathin copper nanowires. By mild thermal annealing, GO can be reduced and high quality Cu r-GO core-shell NWs can be obtained. High performance transparent conducting films were fabricated with these ultrathin core-shell nanowires and excellent optical and electric performance was achieved. The core-shell NW structure enables the production of highly stable conducting films (over 200 days stored in air), which have comparable performance to ITO and silver NW thin films (sheet resistance ∼28 Ω/sq, haze ∼2% at transmittance of ∼90%). PMID:26820809

  14. Flexible magnetic nanoparticles-reduced graphene oxide composite membranes formed by self-assembly in solution.

    PubMed

    Zhu, Guoxing; Liu, Yuanjun; Xu, Zheng; Jiang, Tian; Zhang, Chi; Li, Xun; Qi, Gang

    2010-08-01

    A facile and robust route for the pre-synthesized Fe(3)O(4) nanoparticles (NPs) exclusively assembled on both sides of reduced graphene oxide (RGO) sheets with tunable density forming two-dimensional NPs composite membranes is developed in solution. The assembly is driven by electrostatic attraction, and the nanocomposite sheets display considerable mechanical robustness, such as it can sustain supersonic and solvothermal treatments without NPs falling off, also, can freely float in solution and curl into a tube. The obtained two-dimensional composite grain membranes exhibit superparamagnetic behavior at room temperature but responds astutely to an external magnetic field. In addition, these magnetic composite membranes show an enhanced absorption capability for microwaves. The grain sheets are attractive for biomedical, sensors, environmental applications and electric-magnetic devices benefited from large surfaces, high magnetization moment, and superparamagnetic properties. The effective integration of oxide nanocrystals on RGO sheets provides a new way to design semiconductor-carbon nanocomposites for nanodevices or catalytic applications. PMID:20572256

  15. Crystallographic parameters in geometrically and topologically close-packed superstructures

    SciTech Connect

    Knestaypin, Evgeny A. E-mail: 7mmm81@gmal.com; Morozov, Maksim M. E-mail: 7mmm81@gmal.com; Potekaev, Alexandr I.; Klopotov, Anatoly A.; Markova, Tatyana N.; Klopotov, Vladimir D.

    2014-11-14

    The structures of stoichiometric compositions AB, A{sub 2}B, and A{sub 3}B for structures, B19, L1{sub 0}, L1{sub 2}, D0{sub 19}, D0{sub 22}, D0{sub 23}, D0{sub 24}, A15, C14, C15 and C36 have been investigated based on the analysis of diagrams in coordinates of space-filling coefficients Ψ on superstructural compression ΔΩ/Ω. On the basis of the analysis of the abovementioned diagrams, the equation Ψ = f{sub 0}+f{sub 1}(ΔΩ/Ω) has been obtained, and coefficients f{sub 0} and f{sub 1} of the equation for the investigated structures have been determined. It has been established that values of coefficients f{sub 0} and f{sub 1} for Laves phases have higher values than for all other compounds.

  16. Self-assembly of magnetite nanocubes into helical superstructures.

    PubMed

    Singh, Gurvinder; Chan, Henry; Baskin, Artem; Gelman, Elijah; Repnin, Nikita; Král, Petr; Klajn, Rafal

    2014-09-01

    Organizing inorganic nanocrystals into complex architectures is challenging and typically relies on preexisting templates, such as properly folded DNA or polypeptide chains. We found that under carefully controlled conditions, cubic nanocrystals of magnetite self-assemble into arrays of helical superstructures in a template-free manner with >99% yield. Computer simulations revealed that the formation of helices is determined by the interplay of van der Waals and magnetic dipole-dipole interactions, Zeeman coupling, and entropic forces and can be attributed to spontaneous formation of chiral nanocube clusters. Neighboring helices within their densely packed ensembles tended to adopt the same handedness in order to maximize packing, thus revealing a novel mechanism of symmetry breaking and chirality amplification. PMID:25061133

  17. Electrostatics Controls the Formation of Amyloid Superstructures in Protein Aggregation

    NASA Astrophysics Data System (ADS)

    Foderà, Vito; Zaccone, Alessio; Lattuada, Marco; Donald, Athene M.

    2013-09-01

    The possibility for proteins to aggregate in different superstructures, i.e. large-scale polymorphism, has been widely observed, but an understanding of the physicochemical mechanisms behind it is still out of reach. Here we present a theoretical model for the description of a generic aggregate formed from an ensemble of charged proteins. The model predicts the formation of multifractal structures with the geometry of the growth determined by the electrostatic interactions between single proteins. The model predictions are successfully verified in comparison with experimental curves for aggregate growth allowing us to reveal the mechanism of formation of such complex structures. The model is general and is able to predict aggregate morphologies occurring both in vivo and in vitro. Our findings provide a framework where the physical interactions between single proteins, the aggregate morphology, and the growth kinetics are connected into a single model in agreement with the experimental data.

  18. INTEGRATED SACHS-WOLFE IMPRINT OF SUPERSTRUCTURES ON LINEAR SCALES

    SciTech Connect

    Papai, Peter; Szapudi, Istvan; Granett, Benjamin R.

    2011-05-01

    We build a model for the density and integrated Sachs-Wolfe (ISW) profile of supervoid and supercluster structures. Our model assumes that fluctuations evolve linearly from an initial Gaussian random field. We find these assumptions capable of describing N-body simulations and simulated ISW maps remarkably well on large scales. We construct an ISW map based on locations of superstructures identified previously in the Sloan Digital Sky Survey Luminous Red Galaxy sample. A matched filter analysis of the cosmic microwave background confirms a signal at the 3.2{sigma} confidence level and estimates the radius of the underlying structures to be 55 {+-} 28 h{sup -1} Mpc. The amplitude of the signal, however, is 2{sigma} higher than {Lambda}CDM predictions.

  19. Garden-like perovskite superstructures with enhanced photocatalytic activity

    NASA Astrophysics Data System (ADS)

    Ye, Meidan; Wang, Mengye; Zheng, Dajiang; Zhang, Nan; Lin, Changjian; Lin, Zhiqun

    2014-03-01

    By subjecting amorphous flower-like TiO2 to a facile hydrothermal synthesis in the presence of Sr2+, garden-like perovskite SrTiO3 superstructures were achieved. The amorphous TiO2 was preformed using ZnO flowers as templates. Different three-dimensional SrTiO3 architectures were coexisted in the garden, including SrTiO3 flowers composed of several hollow sword-shaped petals, many sheet-shaped petals or numerous flake-shaped petals, and SrTiO3 grass consisting of a number of long blades. These SrTiO3 superstructures were simultaneously grown on fluorine-doped tin oxide (FTO) substrates. On the basis of a comprehensive study on the effects of growth time, temperature, initial concentrations of precursor, and pH, the formation of these various hierarchical architectures was attributed primarily to the dissolution of amorphous TiO2 and precipitation of perovskite crystals, followed by the Ostwald ripening process of perovskite nanocrystals and self-organization of perovskite building blocks. Interestingly, this approach can be readily extended to create other perovskite structures, including dendritic BaTiO3 and nest-like CaTiO3, as well as PbTiO3 transformed from plate-like pyrochlore Pb2Ti2O6 after post-thermal treatment. Garden-like SrTiO3 superstructures showed a superior photocatalytic performance when compared to other as-prepared semiconductors and perovskite materials (i.e., ZnO, TiO2, BaTiO3, CaTiO3 and PbTiO3), probably due to their intrinsic photocatalytic activity and special garden-like features with a coexistence of various structures that significantly facilitated the adsorption and diffusion of methyl blue (MB) molecules and oxygen species in the photochemical reaction of MB degradation.By subjecting amorphous flower-like TiO2 to a facile hydrothermal synthesis in the presence of Sr2+, garden-like perovskite SrTiO3 superstructures were achieved. The amorphous TiO2 was preformed using ZnO flowers as templates. Different three-dimensional SrTiO3

  20. Hierarchically superstructured prussian blue analogues: spontaneous assembly synthesis and applications as pseudocapacitive materials.

    PubMed

    Yue, Yanfeng; Zhang, Zhiyong; Binder, Andrew J; Chen, Jihua; Jin, Xianbo; Overbury, Steven H; Dai, Sheng

    2015-01-01

    Hierarchically superstructured Prussian blue analogues (hexacyanoferrate, M=Ni(II) , Co(II) and Cu(II) ) are synthesized through a spontaneous assembly technique. In sharp contrast to macroporous-only Prussian blue analogues, the hierarchically superstructured porous Prussian blue materials are demonstrated to possess a high capacitance, which is similar to those of the conventional hybrid graphene/MnO2 nanostructured textiles. Because sodium or potassium ions are involved in energy storage processes, more environmentally neutral electrolytes can be utilized, making the superstructured porous Prussian blue analogues a great contender for applications as high-performance pseudocapacitors. PMID:25385481

  1. Integrated PEV Charging Solutions and Reduced Energy for Occupant Comfort (Brochure)

    SciTech Connect

    Not Available

    2012-01-01

    Brochure on Vehicle Testing and Integration Facility, featuring the Vehicle Modification Facility, Vehicle Test Pad and ReCharge Integrated Demonstration System. Plug-in electric vehicles (PEVs) offer the opportunity to shift transportation energy demands from petroleum to electricity, but broad adoption will require integration with other systems. While automotive experts work to reduce the cost of PEVs, fossil fueled cars and trucks continue to burn hundreds of billions of gallons of petroleum each year - not only to get from point A to point B, but also to keep passengers comfortable with air conditioning and heat. At the National Renewable Energy Laboratory (NREL), three installations form a research laboratory known as the Vehicle Testing and Integration Facility (VTIF). At the VTIF, engineers are developing strategies to address two separate but equally crucial areas of research: meeting the demands of electric vehicle-grid integration and minimizing fuel consumption related to vehicle climate control. Part of NREL's Center for Transportation Technologies and Systems (CTTS), the VTIF is dedicated to renewable and energy efficient solutions. This facility showcases technology and systems designed to increase the viability of sustainably powered vehicles. NREL researchers instrument every class of on-road vehicle, conduct hardware and software validation for electric vehicle (EV) components and accessories, and develop analysis tools and technology for the Department of Energy, other government agencies and industry partners. Research conducted at the VTIF examines the interaction of building energy systems, utility grids, renewable energy sources and PEVs, integrating energy management solutions, and maximizing potential greenhouse gas (GHG) reduction, while smoothing the transition and reducing costs for EV owners. NREL's collaboration with automakers, charging station manufacturers, utilities and fleet operators to assess technologies using VTIF resources is

  2. Washing of gloved hands in antiseptic solution prior to central venous line insertion reduces contamination.

    PubMed

    Kocent, H; Corke, C; Alajeel, A; Graves, S

    2002-06-01

    Glove contamination at the time a central venous catheter is handled is highly undesirable and likely to increase the risk of subsequent line infection. This study was designed to determine how frequently gloves become contaminated during central venous line insertion and to demonstrate the value of glove decontamination immediately prior to handling of the central venous catheter During twenty routine internal jugular catheter insertions the sterility of the operator's gloved fingertips (just prior to handling the intravenous catheter) was assessed by touching the fingertips onto blood agar plates. The gloved hands were then rinsed in chlorhexidine/alcohol and after drying were placed onto a further plate. Contamination was detected in 55% of the prewash plates but in none of the postwash plates. Procedures performed by less experienced resident staff had a higher contamination rate despite there being no evident breach of sterile technique. It is likely that glove contamination results from the persistance of bacteria within the deeper layers of the skin, despite surface disinfection. These bacteria may be released by manipulation of the skin when identifying landmarks. This hypothesis was supported by a subsequent observation that gloves were more highly contaminated after firm touching of the skin rather than light touching. Glove contamination during central line insertion is frequent. Catheter contamination rates could be reduced (without risk or additional cost) by rinsing gloved hands in a solution of chlorhexidine (0.5%) in alcohol (70%) prior to handling the catheter. PMID:12075642

  3. Reduce, reuse and recycle: a green solution to Canada's medical isotope shortage.

    PubMed

    Galea, R; Ross, C; Wells, R G

    2014-05-01

    Due to the unforeseen maintenance issues at the National Research Universal (NRU) reactor at Chalk River and coincidental shutdowns of other international reactors, a global shortage of medical isotopes (in particular technetium-99m, Tc-99m) occurred in 2009. The operation of these research reactors is expensive, their age creates concerns about their continued maintenance and the process results in a large amount of long-lived nuclear waste, whose storage cost has been subsidized by governments. While the NRU has since revived its operations, it is scheduled to cease isotope production in 2016. The Canadian government created the Non-reactor based medical Isotope Supply Program (NISP) to promote research into alternative methods for producing medical isotopes. The NRC was a member of a collaboration looking into the use of electron linear accelerators (LINAC) to produce molybdenum-99 (Mo-99), the parent isotope of Tc-99m. This paper outlines NRC's involvement in every step of this process, from the production, chemical processing, recycling and preliminary animal studies to demonstrate the equivalence of LINAC Tc-99m with the existing supply. This process stems from reusing an old idea, reduces the nuclear waste to virtually zero and recycles material to create a green solution to Canada's medical isotope shortage. PMID:24332878

  4. Aqueous solution synthesis of reduced graphene oxide-germanium nanoparticles and their electrical property testing

    PubMed Central

    2013-01-01

    Aqueous solution synthesis of reduced graphene oxide-germanium nanoparticles (RGO-GeNPs) was developed using graphene oxide (GO) as stabilizer, which could be conducive to obtain better excellent electrical properties. The information about morphology and chemical composition of the nanomaterials were obtained by TEM, FTIR, EDS, and XRD measurements. Stable aqueous dispersibility of RGO-GeNPs was further improved by poly(sodium 4-styrenesulfonate) (PSS) to obtain amphiphilic polymer-coated RGO-GeNPs (PSS-RGO-GeNPs). A possible mechanism to interpret the formation of RGO-GeNPs was proposed. The as-synthesized RGO-GeNPs showed excellent battery performance when used as an anode material for Li ion batteries. The resulting nanocomposites exhibited high specific capacity and good cycling stability after 80 cycles. This study showed a facile strategy to synthetize graphene and Ge nanocomposites which can be a hopeful anode material with excellent electrical properties for lithium ion batteries. PMID:24134406

  5. Laser Solutions for Reducing the Environmental Risks Associated with Orbital Debris and Near Earth Objects

    NASA Technical Reports Server (NTRS)

    Campbell, Jonathan W.; Howell, Joe T. (Technical Monitor)

    2001-01-01

    Increasing activity in space is gradually increasing the amount of orbital debris in low earth orbit. As the debris increases, the environmental risk (hypervelocity collisions) associated with spaceflight also increases. Debris larger than 10 cm can typically be detected and tracked sufficiently to allow risk avoidance to be achieved by maneuvering to safe distances. Risk reduction for objects smaller than I cm may be accomplished through shielding. However, intermediate sized debris remains a problem. A convenient risk reduction solution has been identified using modem laser technology. In this approach, a relatively low energy laser facility operating near e equator may significantly reduce the amount of intermediate sized debris (1 - 10 cm) in a few years of operation. A sufficiently intense laser pulse arriving at a debris objects surface will ablate a micro-thin layer of material. As this hot gas rapidly expands away from the object, a small change in momentum is imparted. The momentum change for one pulse is insignificant. However, since the laser can provide 10-1000 pulses per second over several minutes, the cumulative effect is substantive. The object's perigee may be lowered in this manner into atmosphere where it will be vaporized. This same technique may be employed on a larger scale for risk reduction in asteroids, meteoroids, and comets colliding with the Earth at hypervelocities.

  6. Understanding the formation of CuS concave superstructures with peroxidase-like activity

    NASA Astrophysics Data System (ADS)

    He, Weiwei; Jia, Huimin; Li, Xiaoxiao; Lei, Yan; Li, Jing; Zhao, Hongxiao; Mi, Liwei; Zhang, Lizhi; Zheng, Zhi

    2012-05-01

    Copper sulfide (CuS) concave polyhedral superstructures (CPSs) have been successfully prepared in an ethanolic solution by a simple solvothermal reaction without the use of surfactants or templates. Two typical well defined, high symmetry CuS concave polyhedrons, forming a concave truncated cuboctahedron and icosahedron were prepared. The effect of the reaction time, temperature and different Cu ion and sulfur sources on the formation of CuS CPSs were investigated and a possible formation mechanism was proposed and discussed based on gas chromatography-mass spectrometry. More importantly, we found, for the first time, that the CuS CPSs exhibit intrinsic peroxidase-like activity, as they can quickly catalyze the oxidation of typical horseradish peroxidase (HRP) substrates, 3,3',5,5'-tetramethylbenzidine (TMB) and o-phenylenediamine (OPD), in the presence of hydrogen peroxide. In addition to the recent discoveries regarding peroxidase mimetics on Fe3O4 NPs and carbon nanostructures, our findings suggest a new kind of candidate for peroxidase mimics. This may open up a new application field of CuS micro-nano structures in biodetection, biocatalysis and environmental monitoring.Copper sulfide (CuS) concave polyhedral superstructures (CPSs) have been successfully prepared in an ethanolic solution by a simple solvothermal reaction without the use of surfactants or templates. Two typical well defined, high symmetry CuS concave polyhedrons, forming a concave truncated cuboctahedron and icosahedron were prepared. The effect of the reaction time, temperature and different Cu ion and sulfur sources on the formation of CuS CPSs were investigated and a possible formation mechanism was proposed and discussed based on gas chromatography-mass spectrometry. More importantly, we found, for the first time, that the CuS CPSs exhibit intrinsic peroxidase-like activity, as they can quickly catalyze the oxidation of typical horseradish peroxidase (HRP) substrates, 3

  7. Oligosilane-nanofibers can be prepared through fabrication of permethyldecasilane within a helical superstructure of schizophyllan.

    PubMed

    Haraguchi, Shuichi; Hasegawa, Teruaki; Numata, Munenori; Fujiki, Michiya; Uezu, Kazuya; Sakurai, Kazuo; Shinkai, Seiji

    2005-12-01

    [chemical structure: see text]. Schizophyllan can interact with permethyldecasilane to produce the corresponding decasilane-nanofiber, in which the decasilane adopts helical conformations in a tubular hollow created by the helical superstructure of schizophyllan. PMID:16321002

  8. 22. Top 30/5. Plan of superstructure elevations. Wyoming Valley ...

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

    22. Top 30/5. Plan of superstructure elevations. - Wyoming Valley Flood Control System, Woodward Pumping Station, East of Toby Creek crossing by Erie-Lackawanna Railroad, Edwardsville, Luzerne County, PA

  9. 23. Top 30/6. Plan of superstructure sections. Wyoming Valley ...

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

    23. Top 30/6. Plan of superstructure sections. - Wyoming Valley Flood Control System, Woodward Pumping Station, East of Toby Creek crossing by Erie-Lackawanna Railroad, Edwardsville, Luzerne County, PA

  10. 24. Top 30/7. Plan of superstructure details. Wyoming Valley ...

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

    24. Top 30/7. Plan of superstructure details. - Wyoming Valley Flood Control System, Woodward Pumping Station, East of Toby Creek crossing by Erie-Lackawanna Railroad, Edwardsville, Luzerne County, PA

  11. Joint Simultaneous Reconstruction of Regularized Building Superstructures from Low-Density LIDAR Data Using Icp

    NASA Astrophysics Data System (ADS)

    Wichmann, Andreas; Kada, Martin

    2016-06-01

    There are many applications for 3D city models, e.g., in visualizations, analysis, and simulations; each one requiring a certain level of detail to be effective. The overall trend goes towards including various kinds of anthropogenic and natural objects therein with ever increasing geometric and semantic details. A few years back, the featured 3D building models had only coarse roof geometry. But nowadays, they are expected to include detailed roof superstructures like dormers and chimneys. Several methods have been proposed for the automatic reconstruction of 3D building models from airborne based point clouds. However, they are usually unable to reliably recognize and reconstruct small roof superstructures as these objects are often represented by only few point measurements, especially in low-density point clouds. In this paper, we propose a recognition and reconstruction approach that overcomes this problem by identifying and simultaneously reconstructing regularized superstructures of similar shape. For this purpose, candidate areas for superstructures are detected by taking into account virtual sub-surface points that are assumed to lie on the main roof faces below the measured points. The areas with similar superstructures are detected, extracted, grouped together, and registered to one another with the Iterative Closest Point (ICP) algorithm. As an outcome, the joint point density of each detected group is increased, which helps to recognize the shape of the superstructure more reliably and in more detail. Finally, all instances of each group of superstructures are modeled at once and transformed back to their original position. Because superstructures are reconstructed in groups, symmetries, alignments, and regularities can be enforced in a straight-forward way. The validity of the approach is presented on a number of example buildings from the Vaihingen test data set.

  12. Carbon Footprint of Telemedicine Solutions - Unexplored Opportunity for Reducing Carbon Emissions in the Health Sector

    PubMed Central

    Holmner, Åsa; Ebi, Kristie L.; Lazuardi, Lutfan; Nilsson, Maria

    2014-01-01

    Background The healthcare sector is a significant contributor to global carbon emissions, in part due to extensive travelling by patients and health workers. Objectives To evaluate the potential of telemedicine services based on videoconferencing technology to reduce travelling and thus carbon emissions in the healthcare sector. Methods A life cycle inventory was performed to evaluate the carbon reduction potential of telemedicine activities beyond a reduction in travel related emissions. The study included two rehabilitation units at Umeå University Hospital in Sweden. Carbon emissions generated during telemedicine appointments were compared with care-as-usual scenarios. Upper and lower bound emissions scenarios were created based on different teleconferencing solutions and thresholds for when telemedicine becomes favorable were estimated. Sensitivity analyses were performed to pinpoint the most important contributors to emissions for different set-ups and use cases. Results Replacing physical visits with telemedicine appointments resulted in a significant 40–70 times decrease in carbon emissions. Factors such as meeting duration, bandwidth and use rates influence emissions to various extents. According to the lower bound scenario, telemedicine becomes a greener choice at a distance of a few kilometers when the alternative is transport by car. Conclusions Telemedicine is a potent carbon reduction strategy in the health sector. But to contribute significantly to climate change mitigation, a paradigm shift might be required where telemedicine is regarded as an essential component of ordinary health care activities and not only considered to be a service to the few who lack access to care due to geography, isolation or other constraints. PMID:25188322

  13. Understanding the formation of CuS concave superstructures with peroxidase-like activity.

    PubMed

    He, Weiwei; Jia, Huimin; Li, Xiaoxiao; Lei, Yan; Li, Jing; Zhao, Hongxiao; Mi, Liwei; Zhang, Lizhi; Zheng, Zhi

    2012-06-01

    Copper sulfide (CuS) concave polyhedral superstructures (CPSs) have been successfully prepared in an ethanolic solution by a simple solvothermal reaction without the use of surfactants or templates. Two typical well defined, high symmetry CuS concave polyhedrons, forming a concave truncated cuboctahedron and icosahedron were prepared. The effect of the reaction time, temperature and different Cu ion and sulfur sources on the formation of CuS CPSs were investigated and a possible formation mechanism was proposed and discussed based on gas chromatography-mass spectrometry. More importantly, we found, for the first time, that the CuS CPSs exhibit intrinsic peroxidase-like activity, as they can quickly catalyze the oxidation of typical horseradish peroxidase (HRP) substrates, 3,3',5,5'-tetramethylbenzidine (TMB) and o-phenylenediamine (OPD), in the presence of hydrogen peroxide. In addition to the recent discoveries regarding peroxidase mimetics on Fe(3)O(4) NPs and carbon nanostructures, our findings suggest a new kind of candidate for peroxidase mimics. This may open up a new application field of CuS micro-nano structures in biodetection, biocatalysis and environmental monitoring. PMID:22552534

  14. One-, two-, and three-dimensional superstructures of gold nanorods induced by dimercaptosuccinic acid.

    PubMed

    Sreeprasad, T S; Samal, A K; Pradeep, T

    2008-05-01

    A method is described for assembling gold nanorods into one-, two-, and three-dimensional superstructures. The addition of dimercaptosuccinic acid (DMSA) into the nanorod solution was found to induce self-assembly of the latter to one-dimensional "tapelike", two-dimensional "sheetlike" and three-dimensional "superlattice-like" structures depending on the DMSA concentration. The assembly was found to follow a smectic structure, where the nanorod long axes are parallel to each other. The rods are spaced 8.5 +/- 0.3 nm apart in the resulting structures, which extend over several micrometers in length. Organizations perpendicular to the grid were also found. The nanorod tapes were found to bend, and they form circular assemblies as well. The assembly and morphology of the nanorod structures were characterized by transmission electron microscopy and UV-vis spectroscopy. The effect of the DMSA concentration as well as the pH of the medium was also studied. On the basis of several control experiments utilizing similar molecules, charge neutralization of the nanorods by the carboxylic group of DMSA was found to be the principal reason for such an assembly, while the mercapto groups render additional stability to its structure. A mechanistic model of the assembly is proposed. This type of assembly would plausibly function as a plasmonic waveguide in potential nanodevices. PMID:18393485

  15. The integrated Sachs-Wolfe signal from BOSS superstructures

    NASA Astrophysics Data System (ADS)

    Granett, B. R.; Kovács, A.; Hawken, A. J.

    2015-12-01

    Cosmic structures leave an imprint on the microwave background radiation through the integrated Sachs-Wolfe (ISW) effect. We construct a template map of the linear signal using the Sloan Digital Sky Survey-III Baryon Acoustic Oscillation Survey at redshift 0.43 < z < 0.65. We verify the imprint of this map on the Planck cosmic microwave background (CMB) temperature map at the 97 per cent confidence level and show consistency with the density-temperature cross-correlation measurement. Using this ISW reconstruction as a template, we investigate the presence of ISW sources and further examine the properties of the Granett-Neyrinck-Szapudi supervoid and supercluster catalogue. We characterize the three-dimensional density profiles of these structures for the first time and demonstrate that they are significant structures. Model fits demonstrate that the supervoids are elongated along the line of sight and we suggest that this special orientation may be picked out by the void-finding algorithm in photometric redshift space. We measure the mean temperature profiles in Planck maps from public void and cluster catalogues. In an attempt to maximize the stacked ISW signal, we construct a new catalogue of superstructures based upon local peaks and troughs of the gravitational potential. However, we do not find a significant correlation between these structures and the CMB temperature.

  16. Getting to the core of prion superstructural variability

    PubMed Central

    Torrent, Joan; Lange, Reinhard; Igel-Egalon, Angelique; Béringue, Vincent; Rezaei, Human

    2016-01-01

    ABSTRACT The phenomenon of protein superstructural polymorphism has become the subject of increased research activity. Besides the relevance to explain the existence of multiple prion strains, such activity is partly driven by the recent finding that in many age-related neurodegenerative diseases highly ordered self-associated forms of peptides and proteins might be the structural basis of prion-like processes and strains giving rise to different disease phenotypes. Biophysical studies of prion strains have been hindered by a lack of tools to characterize inherently noncrystalline, heterogeneous and insoluble proteins. A description of the pressure response of prion quaternary structures might change this picture. This is because applying pressure induces quaternary structural changes of PrP, such as misfolding and self-assembly. From the thermodynamics of these processes, structural features in terms of associated volume changes can then be deduced. We suggest that conformation-enciphered prion strains can be distinguished in terms of voids in the interfaces of the constituting PrP protomers and thus in their volumetric properties. PMID:26636374

  17. Ti{sub 5}O{sub 5} superstructures of cubic titanium monoxide

    SciTech Connect

    Gusev, A. I.

    2013-08-15

    A cubic model is proposed for the Ti{sub 5}O{sub 5} (Ti{sub 5} Black-Small-Square O{sub 5}{open_square} {identical_to} Ti{sub 90} Black-Small-Square {sub 18}O{sub 90}{open_square}{sub 18}) superstructure of nonstoichiometric titanium monoxide Ti{sub x}O{sub z} with double imperfection. The unit cell of the cubic Ti{sub 5}O{sub 5} superstructure has the threefold lattice parameter of the unit cell of the basis disordered B1 structure of Ti{sub x}O{sub z} monoxide and belongs to space group Pm 3-bar m . The channel of the disorder-order transition, i.e., Ti{sub x}O{sub z} (space group Fm 3-bar m)-Ti{sub 5}O{sub 5} (space group Pm 3-bar m), includes 75 superstructure vectors of seven stars (k{sub 10}), (k{sub 7}), (k{sub 6(1)}), (k{sub 6(2)}), (k{sub 4(1)}), (k{sub 4(2)}), and (k{sub 1}). The distribution functions of Ti and O atoms over the sites of the cubic Ti{sub 5}O{sub 5} superstructure are calculated. A comparison of the X-ray and electron diffraction data obtained for ordered TiO{sub 1.087} monoxide with the theoretical simulation results supports the existence of the cubic Ti{sub 5}O{sub 5} superstructure. The cubic (space group Pm 3-bar m) Ti{sub 5}O{sub 5} superstructure is shown to be a high-temperature structure relative to the well-known monoclinic (space group C2/m) superstructure of the same type.

  18. Tracking morphologies at the nanoscale: self-assembly of an amphiphilic designer peptide into a double helix superstructure

    PubMed Central

    Kornmueller, Karin; Letofsky-Papst, Ilse; Gradauer, Kerstin; Mikl, Christian; Cacho-Nerin, Fernando; Leypold, Mario; Keller, Walter; Leitinger, Gerd; Amenitsch, Heinz; Prassl, Ruth

    2015-01-01

    Hierarchical self-assembly is a fundamental principle in nature, which gives rise to astonishing supramolecular architectures that offer an inspiration for the development of innovative materials in nanotechnology. Here we present the unique structure of a cone-shaped amphiphilic designer peptide. When tracking its concentration-dependent morphologies, we observed elongated bilayered single tapes at the beginning of the assembly process, which further developed into novel double-helix-like superstructures at increased concentrations. This architecture is characterized by a tight intertwisting of two individual helices, resulting in a periodic pitch size over their total lengths of several hundred nanometers. Solution X-ray scattering data revealed a marked 2-layered internal organization. All these characteristics remained unaltered for the investigated period of almost three months. In their collective morphology the assemblies are integrated into a network with hydrogel characteristics. Such a peptide based structure holds promise for a building block of next-generation nanostructured biomaterials. PMID:26290684

  19. Laser-induced chemical liquid phase deposition of copper from aqueous solutions without reducing agents

    SciTech Connect

    Kochemirovsky, V A; Tumkin, I I; Logunov, L S; Safonov, S V; Menchikov, Leonid G

    2012-08-31

    Laser-induced chemical liquid phase deposition of copper without a traditional reducing agent has been used for the first time to obtain conductive patterns on a dielectric surface having a reducing ability. It is shown that phenol-formaldehyde binder of the dielectric (glass fibre) can successfully play the role of a reducing agent in this process. The resulting copper sediments have low electrical resistance and good topology. (interaction of laser radiation with matter. laser plasmas)

  20. Superstructure of Tetrataenite from the Saint Severin Meteorite

    NASA Astrophysics Data System (ADS)

    Tagai, T.; Takeda, H.; Fukuda, T.

    1992-07-01

    Tetrataenite, observed in slow-cooled meteorites, is characterized by the ordered structure of FeNi and the tetragonal distortion from face-centered cubic taenite. The ordering of Fe/Ni was performed in the extra-slow cooling (e.g., 0.1-100 degrees C/m.y.) at the temperature below 300 degrees C (Clarke and Scott, 1980: Albertsen, 1981). The ordering of Fe and Ni in tetrataenite has mainly been confirmed by Mossbauer spectra (Danon et al., 1979). A tetrataenite single crystal of about 40 micrometers in diameter could be selected from the Saint-Severin meteorite (LL6). The chemical composition of the sample was determined to be FeNi by electron probe microanalysis. The lattice constants were determined on the assumption of triclinic symmetry on the diffractometer as: a = 3.581(2), b = 3.582(2), c = 3.587(2) angstrom, alpha = 90.03(3), beta = 90.04(3), gamma = 90.00(3) degrees. The lattice constants show the clear tendency of the tetragonal lattice symmetry within the experimental error. No threefold twinning along [111] was detected by high resolution X- ray diffraction. The diffraction data were collected on a four- circle diffractometer using Moka radiation. A total of 1484 reflections were measured and 696 independent reflections (>1 sigma) were used for the structure determination. Then the same crystal was supplied to the diffraction experiments by synchrotron radiation. The diffraction data were collected using the X-ray of wavelength = 1.746 angstroms. The correction parameter for anomalous scattering in the wavelength are for Fe atom f' = -6.299, f" = 0.469, and for Ni atom f' = -1.740, f" = 0.638. Because of small lattice constants and rather long wavelength, only 25 independent reflections were collected. In the ordered structure of the space group symmetry P4/mmm, all the atoms must occupy special positions. The intensities of the superstructure reflections should be interpreted only by the difference of scattering factors of Fe and Ni. But the model of P4

  1. Block-oriented modeling of superstructure optimization problems

    SciTech Connect

    Friedman, Z; Ingalls, J; Siirola, JD; Watson, JP

    2013-10-15

    We present a novel software framework for modeling large-scale engineered systems as mathematical optimization problems. A key motivating feature in such systems is their hierarchical, highly structured topology. Existing mathematical optimization modeling environments do not facilitate the natural expression and manipulation of hierarchically structured systems. Rather, the modeler is forced to "flatten" the system description, hiding structure that may be exploited by solvers, and obfuscating the system that the modeling environment is attempting to represent. To correct this deficiency, we propose a Python-based "block-oriented" modeling approach for representing the discrete components within the system. Our approach is an extension of the Pyomo library for specifying mathematical optimization problems. Through the use of a modeling components library, the block-oriented approach facilitates a clean separation of system superstructure from the details of individual components. This approach also naturally lends itself to expressing design and operational decisions as disjunctive expressions over the component blocks. By expressing a mathematical optimization problem in a block-oriented manner, inherent structure (e.g., multiple scenarios) is preserved for potential exploitation by solvers. In particular, we show that block-structured mathematical optimization problems can be straightforwardly manipulated by decomposition-based multi-scenario algorithmic strategies, specifically in the context of the PySP stochastic programming library. We illustrate our block-oriented modeling approach using a case study drawn from the electricity grid operations domain: unit commitment with transmission switching and N - 1 reliability constraints. Finally, we demonstrate that the overhead associated with block-oriented modeling only minimally increases model instantiation times, and need not adversely impact solver behavior. (C) 2013 Elsevier Ltd. All rights reserved.

  2. Supersymmetric soliton solution in a dimensionally reduced Schroedinger-Chern-Simons model

    SciTech Connect

    Sourrouille, Lucas

    2011-02-15

    We obtain, by dimensional reduction, a (1+1) supersymmetric system introduced in the description of ultracold quantum gases. The correct supercharges are identified and their algebra is constructed. Finally, novel solitonic equations emerge and their solution is constructed for the bosonic case.

  3. Combined Tin-Containing Fluoride Solution and CO2 Laser Treatment Reduces Enamel Erosion in vitro.

    PubMed

    Esteves-Oliveira, Marcella; Witulski, Nadine; Hilgers, Ralf-Dieter; Apel, Christian; Meyer-Lueckel, Hendrik; Eduardo, Carlos de Paula

    2015-01-01

    The aim of this in vitro study was to evaluate the effect of combined CO2 laser and tin-containing fluoride treatment on the formation and progression of enamel erosive lesions. Ninety-six human enamel samples were obtained, stored in thymol solution and, after surface polishing, randomly divided into 6 different surface treatment groups (n = 16 in each group) as follows: no treatment, control (C); one CO2 laser irradiation (L1); two CO2 laser irradiations (L2); daily application of fluoride solution (F); combined daily fluoride solution + one CO2 laser irradiation (L1F), and combined daily fluoride solution + two CO2 laser irradiations (L2F). Laser irradiation was performed at 0.3 J/cm2 (5 µs/226 Hz/10.6 µm) on day 1 (L1) and day 6 (L2). The fluoride solution contained AmF/NaF (500 ppm F), and SnCl2 (800 ppm Sn) at pH 4.5. After surface treatment the samples were submitted to an erosive cycling over 10 days, including immersion in citric acid (2 min/0.05 M/pH = 2.3) 6 times daily and storage in remineralization solution (≥1 h) between erosive attacks. At the end of each cycling day, the enamel surface loss (micrometers) was measured using a 3D laser profilometer. Data were statistically analyzed by means of a 2-level mixed effects model and linear contrasts (α = 0.05). Group F (-3.3 ± 2.0 µm) showed significantly lower enamel surface loss than groups C (-27.22 ± 4.1 µm), L1 (-18.3 ± 4.4 µm) and L2 (-16.3 ± 5.3 µm) but higher than L1F (-1.0 ± 4.4 µm) and L2F (1.4 ± 3.2 µm, p < 0.05). Under the conditions of this in vitro study, the tin-containing fluoride solution caused 88% reduction of enamel surface loss, while its combination with CO2 laser irradiation at 0.3 J/cm2 hampered erosive loss almost completely. PMID:26418736

  4. Chlorhexidine-based antiseptic solutions effectively reduce catheter-related bacteremia.

    PubMed

    Onder, Ali Mirza; Chandar, Jayanthi; Billings, Anthony; Diaz, Rosa; Francoeur, Denise; Abitbol, Carolyn; Zilleruelo, Gaston

    2009-09-01

    The aim of this retrospective study was to investigate if the application of chlorhexidine-based solutions (ChloraPrep) to the exit site and the hub of long-term hemodialysis catheters could prevent catheter-related bacteremia (CRB) and prolong catheter survival when compared with povidone-iodine solutions. There were 20,784 catheter days observed. Povidone-iodine solutions (Betadine) were used in the first half of the study and ChloraPrep was used in the second half for all the patients. Both groups received chlorhexidine-impregnated dressings at the exit sites. The use of ChloraPrep significantly decreased the incidence of CRB (1.0 vs 2.2/1,000 catheter days, respectively, P = 0.0415), and hospitalization due to CRB (1.8 days vs 4.1 days/1,000 catheter days, respectively, P = 0.0416). The incidence of exit site infection was similar for the two groups. Both the period of overall catheter survival (207.6 days vs 161.1 days, P = 0.0535) and that of infection-free catheter survival (122.0 days vs 106.9 days, P = 0.1100) tended to be longer for the catheters cleansed with ChloraPrep, with no statistical significance. In conclusion, chlorhexidine-based solutions are more effective for the prevention of CRB than povidone-iodine solutions. This positive impact cannot be explained by decreased number of exit site infections. This study supports the notion that the catheter hub is the entry site for CRB. PMID:19296135

  5. Experimental testing of a smart FRP-concrete composite bridge superstructure

    NASA Astrophysics Data System (ADS)

    Wang, Yanlei; Hao, Qingduo; Ou, Jinping

    2010-04-01

    A new kind of smart fiber reinforced polymer (FRP)-concrete composite bridge superstructure, which consists of two bridge decks and each bridge deck is comprised of four FRP box sections combined with a thin layer of concrete in the compression zone, was developed by using eight embedded FBG sensors in the top and bottom flanges of the FRP box sections at mid-span section of one bridge deck along longitudinal direction, respectively. The flexural behavior of the proposed smart composite bridge superstructure was experimentally studied in four-point loading. The longitudinal strains of the composite bridge superstructure were recorded using the embedded FBG sensors as well as the surfacebonded electric resistance strain gauges. Test results indicate that the FBG sensors can faithfully record the longitudinal strain of the composite bridge superstructure in tension at bottom flange of the FRP box sections or in compression at top flange over the entire loading range, as compared with the surface-bonded strain gauges. The proposed smart FRPconcrete composite bridge superstructure can monitor its longitudinal strains in serviceability limit state as well as in strength limit state, and will has wide applications for long-term monitoring in civil engineering.

  6. Light-Directed Dynamic Chirality Inversion in Functional Self-Organized Helical Superstructures.

    PubMed

    Bisoyi, Hari Krishna; Li, Quan

    2016-02-24

    Helical superstructures are widely observed in nature, in synthetic polymers, and in supramolecular assemblies. Controlling the chirality (the handedness) of dynamic helical superstructures of molecular and macromolecular systems by external stimuli is a challenging task, but is of great fundamental significance with appealing morphology-dependent applications. Light-driven chirality inversion in self-organized helical superstructures (i.e. cholesteric, chiral nematic liquid crystals) is currently in the limelight because inversion of the handedness alters the chirality of the circularly polarized light that they selectively reflect, which has wide potential for application. Here we discuss the recent developments toward inversion of the handedness of cholesteric liquid crystals enabled by photoisomerizable chiral molecular switches or motors. Different classes of chiral photoresponsive dopants (guests) capable of conferring light-driven reversible chirality inversion of helical superstructures fabricated from different nematic hosts are discussed. Rational molecular designs of chiral molecular switches toward endowing handedness inversion to the induced helical superstructures of cholesteric liquid crystals are highlighted. This Review is concluded by throwing light on the challenges and opportunities in this emerging frontier, and it is expected to provide useful guidelines toward the development of self-organized soft materials with stimuli-directed chirality inversion capability and multifunctional host-guest systems. PMID:26764018

  7. An investigation of carbonaceous materials reducing ferric ions in aqueous solution

    NASA Astrophysics Data System (ADS)

    Cooke, A. V.; Chilton, J. P.; Fray, D. J.

    1988-10-01

    By substituting the ferrous to ferric oxidation for anodic oxygen evolution in an electrowinning cell, it is possible to reduce the cell voltage by about 1 V. However, it is then necessary to reduce the ferric back to ferrous and, depending on the circumstances, acid needs to be cogenerated. Various possible reductants are discussed, and experiments are described on the use of lignite and other carbonaceous materials to reduce the ferric ion. It was found that lignite was able to reduce the ferric ion, in situ in the electrowinning cell, but that the rate of reduction was compatible only with a maximum current density of about 40 Am-2. The efficiency was increased by periodically interrupting the current flow.

  8. Interaction of cyanocobalamin with sulfur-containing reducing agents in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Salnikov, D. S.; Dereven'kov, I. A.; Artyushina, E. N.; Makarov, S. V.

    2013-01-01

    The kinetics and mechanism of cyanocobalamin reduction by sodium hydroxymethanesulfinate and dithionite in alkaline media are studied. It is established that the character of the rate-determining step depends on the concentration of the reducing agents: when they are in excess, it is a step of elimination of cyanocobalamin, at lower concentrations of reducing agents a rate-determining is a step of their addition to cobalamin.

  9. Excessive Exoergicity Reduces Singlet Exciton Fission Efficiency of Heteroacenes in Solutions.

    PubMed

    Zhang, You-Dan; Wu, Yishi; Xu, Yanqing; Wang, Qiang; Liu, Ke; Chen, Jian-Wei; Cao, Jing-Jing; Zhang, Chunfeng; Fu, Hongbing; Zhang, Hao-Li

    2016-06-01

    The energy difference between a singlet exciton and twice of a triplet exciton, ΔESF, provides the thermodynamic driving force for singlet exciton fission (SF). This work reports a systematic investigation on the effect of ΔESF on SF efficiency of five heteroacenes in their solutions. The low-temperature, near-infrared phosphorescence spectra gave the energy levels of the triplet excitons, allowing us to identify the values of ΔESF, which are -0.58, -0.34, -0.31, -0.32, and -0.34 eV for the thiophene, benzene, pyridine, and two tetrafluorobenzene terminated molecules, respectively. Corresponding SF efficiencies of the five heteroacenes in 0.02 M solutions were determined via femtosecond transient absorption spectroscopy to be 117%, 124%, 140%, 132%, and 135%, respectively. This result reveals that higher ΔESF is not, as commonly expected, always beneficial for higher SF efficiency in solution phase. On the contrary, excessive exoergicity results in reduction of SF efficiency in the heteroacenes due to the promotion of other competitive exciton relaxation pathways. Therefore, it is important to optimize thermodynamic driving force when designing organic materials for high SF efficiency. PMID:27167770

  10. Integrability aspects and soliton solutions for the inhomogeneous reduced Maxwell-Bloch system in nonlinear optics with symbolic computation

    NASA Astrophysics Data System (ADS)

    Hao, Hui-Qin; Zhang, Jian-Wen

    2015-05-01

    In this paper, we investigate the inhomogeneous reduced Maxwell-Bloch system, which describes the propagation of the intense ultra-short optical pulses through an inhomogeneous two-level dielectric medium. Through symbolic computation, the integrability aspects including the Painlevé integrable condition, Lax pair and infinite conservation laws are derived. By virtue of the Darboux transformation method, one- and two-soliton solutions are generated on the nonvanishing background, including the bright solitons, dark solitons, periodic solutions and some two-soliton solutions. The asymptotic analysis method is performed to verify the elastic interaction between two solitons. Furthermore, by virtue of some figures, the dynamic properties of those solitons are discussed. The results may be useful in the study of the ultrashort pulses propagation in such situations as the model of the two-level dielectric media.

  11. Superstructured Carbon Nanotube/Porous Silicon Hybrid Materials for Lithium-Ion Battery Anodes

    NASA Astrophysics Data System (ADS)

    Lee, Jun-Ki; Kang, Shin-Hyun; Choi, Sung-Min

    2015-03-01

    High energy Li-ion batteries (LIBs) are in great demand for electronics, electric-vehicles, and grid-scale energy storage. To further increase the energy and power densities of LIBs, Si anodes have been intensively explored due to their high capacity, and high abundance compared with traditional carbon anodes. However, the poor cycle-life caused by large volume expansion during charge/discharge process has been an impediment to its applications. Recently, superstructured Si materials were received attentions to solve above mentioned problem in excellent mechanical properties, large surface area, and fast Li and electron transportation aspects, but applying superstructures to anode is in early stage yet. Here, we synthesized superstructured carbon nanotubes (CNTs)/porous Si hybrid materials and its particular electrochemical properties will be presented. Department of Nuclear and Quantum Engineering

  12. Challenges and Potential Solutions for Reducing Climate Control Loads in Conventional and Hybrid Vehicles

    SciTech Connect

    Farrington, R.B., Anderson, R., Blake, D.M., Burch, S.D.; Cuddy, M.R., Keyser, M.A., Rugh, J.P.

    1999-01-01

    The National Renewable Energy Laboratory, a U.S. Department of Energy national laboratory, is collaborating with U.S. automotive manufacturers to develop innovative techniques to reduce national fuel consumption and vehicle tailpipe emissions by reducing vehicle climate control loads. A new U.S. emissions test, the Supplemental Federal Test Procedure (SFTP), will soon begin measuring tailpipe emissions with the air conditioning system operating. Modeled results show that emissions of oxides of nitrogen (NOx) and carbon monoxide (CO) more than double during the air conditioning part of the SFTP. Reducing the transmittance of the glazing can have a greater impact on the cabin soak temperature than ventilating the vehicle during a hot soak. Reducing the amount of outside air can decrease cooling and heating loads but requires that the recirculated air be cleaned. We discuss a photocatalytic oxidation air-cleaning process for removing volatile organic compounds and bioareosols. We conclude with an example of modeling the thermal comfort of the occupants. An auxiliary load increase of only 400 Watts (W) results in a 0.4 km/L (1 mpg) decrease for a conventional 11.9-L/100-km (28-mpg) vehicle. If every vehicle in the United States were to save only 0.4 km/L (1 mpg), $4 billion (U.S. dollars) would be saved annually in gasoline and oil costs. Further information can be found at http://www.ctts.nrel.gov/auxload.html.

  13. PROVIDING SOLUTIONS FOR A BETTER TOMORROW: REDUCING THE RISKS ASSOCIATED WITH LEAD IN SOIL; URL:

    EPA Science Inventory

    This brief publication describes, in general language, the health risks associated with exposure to soil and dust contaminated with lead as well as an innovative method to immobilize lead contaminants in the soil (and thereby reduce the risk of exposure) at Superfund sites. Also ...

  14. The effect of sulfated polysaccharides on the crystallization of calcite superstructures

    NASA Astrophysics Data System (ADS)

    Fried, Ruth; Mastai, Yitzhak

    2012-01-01

    Calcite with unique morphology and uniform size has been successfully synthesized in the presence of classes of polysaccharides based on carrageenans. In the crystallization of calcite, the choice of different carrageenans, (iota, lambda and kappa), as additives concedes systematic study of the influence of different chemical structures and particularly molecular charge on the formation of CaCO 3 crystals. The uniform calcite superstructures are formed by assemblies and aggregation of calcite crystals. The mechanism for the formation of calcite superstructures was studied by a variety of techniques, SEM, TEM, XRD, time-resolved conductivity and light scattering measurements, focusing on the early stages of crystals' nucleation and aggregation.

  15. An ordered mesoporous Ag superstructure synthesized via a template strategy for surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Tian, Cuifeng; Li, Jiang; Ma, Chunsheng; Wang, Ping; Sun, Xiaohong; Fang, Jixiang

    2015-07-01

    Surface-enhanced Raman scattering (SERS) substrates with high density and uniformity of nanogaps are proven to enhance the reproducibility and sensitivity of the Raman signal. Up to now, the syntheses of a highly ordered gold or silver superstructure with a controllable nanoparticle size and a well-defined particle gap have been quite limited. Here, we reported an ordered mesoporous silver superstructure replicated by using ordered mesoporous KIT-6 and SAB-15 as templates. By means of a nanocasting process, the ordered mesoporous Ag superstructure was successfully synthesized, which shows uniform distribution of the nanowire diameter (10 nm) and nanogap size (~2 nm), thus exhibiting a high Raman enhancement of ~109. The finite difference time-domain (FDTD) results indicate that the ordered mesoporous Ag superstructure has a uniform distribution of hot spots. Therefore, the mesoporous silica template strategy presented here could lead to a new class of high quality SERS substrates providing extraordinary potential for diverse applications.Surface-enhanced Raman scattering (SERS) substrates with high density and uniformity of nanogaps are proven to enhance the reproducibility and sensitivity of the Raman signal. Up to now, the syntheses of a highly ordered gold or silver superstructure with a controllable nanoparticle size and a well-defined particle gap have been quite limited. Here, we reported an ordered mesoporous silver superstructure replicated by using ordered mesoporous KIT-6 and SAB-15 as templates. By means of a nanocasting process, the ordered mesoporous Ag superstructure was successfully synthesized, which shows uniform distribution of the nanowire diameter (10 nm) and nanogap size (~2 nm), thus exhibiting a high Raman enhancement of ~109. The finite difference time-domain (FDTD) results indicate that the ordered mesoporous Ag superstructure has a uniform distribution of hot spots. Therefore, the mesoporous silica template strategy presented here could

  16. Surface Superstructure of Carbon Nanotubes on Highly Oriented Pyrolytic Graphite Annealed at Elevated Temperatures

    NASA Astrophysics Data System (ADS)

    An, Bai; Fukuyama, Seiji; Yokogawa, Kiyoshi; Yoshimura, Masamichi

    1998-06-01

    Carbon nanotubes deposited on highly oriented pyrolytic graphite (HOPG) are annealed in ultra high vacuum. The effect of annealing temperature on the surface morphology of the carbon nanotubes on HOPG is examined by scanning tunneling microscopy. The ring-like surface superstructure of (\\sqrt {3}× \\sqrt {3})R30° of graphite is found on the carbon nanotubes annealed above 1593 K. The tips of the carbon nanotubes are destroyed and the stacking misarrangement between the upper and the lower walls of the tube join with HOPG resulting in the superstructure.

  17. Cold- and Beam Test of the First Prototypes of the Superstructure for the TESLA Collider

    SciTech Connect

    Baboi, Nicoleta

    2003-08-08

    After three years of preparation, two superstructures, each made of two superconducting 7-cell weakly coupled subunits, have been installed in the TESLA Test Facility linac (TTF) for the cold- and beam-test. The energy stability, the HOMs damping, the frequency and the field adjustment methods were tested. The measured results confirmed expectation on the superstructure performance and proved that alternative layout for the 800 GeV upgrade of the TESLA collider, as it was proposed in TDR, is feasible. We report on the test and give here an overview of its results which are commented in more detail elsewhere in these Proceedings.

  18. Hierarchically Superstructured Prussian Blue Analogues: Spontaneous Assembly Synthesis and Applications as Pseudocapacitive Materials

    DOE PAGESBeta

    Yue, Yanfeng; Zhang, Zhiyong; Binder, Andrew J.; Chen, Jihua; Jin, Xianbo; Overbury, Steven; Dai, Sheng

    2014-11-10

    Hierarchically superstructured Prussian blue analogues (hexa- conventional hybrid graphene/MnO2 nanostructured textiles. cyanoferrate, M = NiII, CoII and CuII) are synthesized through Because sodium or potassium ions are involved in energy stor- a spontaneous assembly technique. In sharp contrast to mac- age processes, more environmentally neutral electrolytes can roporous-only Prussian blue analogues, the hierarchically su- be utilized, making the superstructured porous Prussian blue perstructured porous Prussian blue materials are demonstrated analogues a great contender for applications as high-per- to possess a high capacitance, which is similar to those of the formance pseudocapacitors.

  19. Hierarchically Superstructured Prussian Blue Analogues: Spontaneous Assembly Synthesis and Applications as Pseudocapacitive Materials

    SciTech Connect

    Yue, Yanfeng; Zhang, Zhiyong; Binder, Andrew J.; Chen, Jihua; Jin, Xianbo; Overbury, Steven; Dai, Sheng

    2014-11-10

    Hierarchically superstructured Prussian blue analogues (hexa- conventional hybrid graphene/MnO2 nanostructured textiles. cyanoferrate, M = NiII, CoII and CuII) are synthesized through Because sodium or potassium ions are involved in energy stor- a spontaneous assembly technique. In sharp contrast to mac- age processes, more environmentally neutral electrolytes can roporous-only Prussian blue analogues, the hierarchically su- be utilized, making the superstructured porous Prussian blue perstructured porous Prussian blue materials are demonstrated analogues a great contender for applications as high-per- to possess a high capacitance, which is similar to those of the formance pseudocapacitors.

  20. Technology Solutions Case Study: Overcoming Comfort Issues Due to Reduced Flow Room Air Mixing

    SciTech Connect

    2015-03-01

    Energy efficiency upgrades reduce heating and cooling loads on a house. With enough load reduction and if the HVAC system warrants replacement, the HVAC system is often upgraded with a more efficient, lower capacity system that meets the loads of the upgraded house. In this project, IBACOS studied when HVAC equipment is downsized and ducts are unaltered to determine conditions that could cause a supply air delivery problem and to evaluate the feasibility of modifying the duct systems using minimally invasive strategies to improve air distribution.

  1. Immobilizing U from solution by immobilized sulfate-reducing bacteria of desulfovibrio desulfuricans

    NASA Astrophysics Data System (ADS)

    Xu, Hulfang; Barton, Larry L.

    2000-07-01

    As determined by transmission electron microscopy, the reduction of uranyl accetate by immobilized cells of Desulfovibrio desulfuricans results in the production of black uraninite nanocrystals precipitated outside the cell. Some nanocrystals are associated with outer membranes of the cell as revealed from cross sections of these metabolically active sulfate-reducing bacteria. The nanocrystals have an average diameter of 5 nm and have anhedral shape. It is proposed that cytochrome in these cells has an important role in the reduction of uranyl through transferring electron from molecular hydrogen or lactic acid to uranyl ions.

  2. Reducing infection risk in implant-based breast-reconstruction surgery: challenges and solutions.

    PubMed

    Ooi, Adrian Sh; Song, David H

    2016-01-01

    Implant-based procedures are the most commonly performed method for postmastectomy breast reconstruction. While donor-site morbidity is low, these procedures are associated with a higher risk of reconstructive loss. Many of these are related to infection of the implant, which can lead to prolonged antibiotic treatment, undesired additional surgical procedures, and unsatisfactory results. This review combines a summary of the recent literature regarding implant-related breast-reconstruction infections and combines this with a practical approach to the patient and surgery aimed at reducing this risk. Prevention of infection begins with appropriate reconstructive choice based on an assessment and optimization of risk factors. These include patient and disease characteristics, such as smoking, obesity, large breast size, and immediate reconstructive procedures, as well as adjuvant therapy, such as radiotherapy and chemotherapy. For implant-based breast reconstruction, preoperative planning and organization is key to reducing infection. A logical and consistent intraoperative and postoperative surgical protocol, including appropriate antibiotic choice, mastectomy-pocket creation, implant handling, and considered acellular dermal matrix use contribute toward the reduction of breast-implant infections. PMID:27621667

  3. Implementation of a solution Cloud Computing with MapReduce model

    NASA Astrophysics Data System (ADS)

    Baya, Chalabi

    2014-10-01

    In recent years, large scale computer systems have emerged to meet the demands of high storage, supercomputing, and applications using very large data sets. The emergence of Cloud Computing offers the potentiel for analysis and processing of large data sets. Mapreduce is the most popular programming model which is used to support the development of such applications. It was initially designed by Google for building large datacenters on a large scale, to provide Web search services with rapid response and high availability. In this paper we will test the clustering algorithm K-means Clustering in a Cloud Computing. This algorithm is implemented on MapReduce. It has been chosen for its characteristics that are representative of many iterative data analysis algorithms. Then, we modify the framework CloudSim to simulate the MapReduce execution of K-means Clustering on different Cloud Computing, depending on their size and characteristics of target platforms. The experiment show that the implementation of K-means Clustering gives good results especially for large data set and the Cloud infrastructure has an influence on these results.

  4. Reducing infection risk in implant-based breast-reconstruction surgery: challenges and solutions

    PubMed Central

    Ooi, Adrian SH; Song, David H

    2016-01-01

    Implant-based procedures are the most commonly performed method for postmastectomy breast reconstruction. While donor-site morbidity is low, these procedures are associated with a higher risk of reconstructive loss. Many of these are related to infection of the implant, which can lead to prolonged antibiotic treatment, undesired additional surgical procedures, and unsatisfactory results. This review combines a summary of the recent literature regarding implant-related breast-reconstruction infections and combines this with a practical approach to the patient and surgery aimed at reducing this risk. Prevention of infection begins with appropriate reconstructive choice based on an assessment and optimization of risk factors. These include patient and disease characteristics, such as smoking, obesity, large breast size, and immediate reconstructive procedures, as well as adjuvant therapy, such as radiotherapy and chemotherapy. For implant-based breast reconstruction, preoperative planning and organization is key to reducing infection. A logical and consistent intraoperative and postoperative surgical protocol, including appropriate antibiotic choice, mastectomy-pocket creation, implant handling, and considered acellular dermal matrix use contribute toward the reduction of breast-implant infections. PMID:27621667

  5. Turbulence structure of drag-reducing surfactant solution in two-dimensional channel with additional heat transfer enhancement method

    SciTech Connect

    Li, P.W.; Daisaka, H.; Kawaguchi, Y.; Yabe, A.; Hishida, K.; Maeda, M.

    1999-07-01

    The turbulent characteristics of a surfactant water solution in changing from drag-reducing flow to turbulent flow inside a two-dimensional smooth channel and in changing from turbulent flow to drag-reducing flow in the same channel with a mesh plug were investigated through LDV measurement in this study. The mesh plug was used to exert high shear stress to destroy micelle structures in the surfactant solution so that turbulence could be produced for better heat transfer. The two-component LDV system was installed on a movable platform, which could be moved streamwise of the flow to measure the two-dimensional velocity at different stations downstream from the mesh plug. The surfactant tested was Cetyltrimethyl ammonium chloride (C{sub 16}H{sub 33}N(CH{sub 3}){sub 3}Cl, abbreviated as CTAC). Local tap water was used as solvent and same weight concentration of sodium salicylate was used as the counter-ion material. The investigation of turbulent parameters for the drag-reducing flow with increasing Reynolds number showed that when the Reynolds number exceeded the drag-reducing region, the turbulent character was the same as that of water. The turbulent parameters of surfactant flow downstream the mesh plug showed that the high heat transfer region had the same turbulent intensity as that of water flow. As the critical Reynolds number was approached, it became easier to obtain such a turbulent region by mesh plug. In such cases, the mesh helped to create high wall shear stress and therefore to destroy the super-ordered structures of rod-like micelles for introducing turbulence. However, it was found that the turbulent intensities of the velocity gradually decreased to the same as those of drag-reducing flow downstream from the mesh because the mesh plug only produced a local high shear stress.

  6. DEMOLISHING A COLD WARE ERA FULE STORAGE BASIN SUPERSTRUCTURE LADEN WITH ASBESTOS

    SciTech Connect

    LLOYD ER; STEVENS JM; DAGAN EB; ORGILL TK; GREEN MA; LARSON CH; ZINSLI LC

    2009-01-12

    The K East (KE) Basin facilities are located near the north end of the Hanford Site's 100 K area. The facilities were built in 1950 as part of the KE Reactor complex and constructed within 400 meters of the Columbia River, which is the largest river in the Pacific Northwest and by volume the fourth largest river in the United States. The basin, located adjacent to the reactor, was used for the underwater storage of irradiated nuclear fuel discharged from the reactor. The basin was covered by a superstructure comprising steel columns and beams, concrete, and cement asbestos board (CAB) siding. The project's mission was to complete demolition of the structure over the KE Basin within six months of turnover from facility deactivation activities. The demolition project team applied open-air demolition techniques to bring the facility to slab-on-grade. Several innovative techniques were used to control contamination and maintain contamination control within the confines of the demolition exclusion zone. The techniques, which focused on a defense-in-depth approach, included spraying fixatives on interior and exterior surfaces before demolition began; applying fixatives during the demolition; misting using a fine spray of water during demolition; and demolishing the facility systematically. Another innovative approach that made demolition easier was to demolish the building with the non-friable CAB remaining in place. The CAB siding covered the exterior of the building and portions of the interior walls, and was an integral part of the multiple-layered roof. The project evaluated the risks involved in removing the CAB material in a radiologically contaminated environment and determined that radiological dose rates and exposure to radiological contamination and industrial hazards would be significantly reduced by using heavy equipment to remove the CAB during demolition. The ability to perform this demolition safely and without spreading contamination (radiological or

  7. DEMOLISHING A COLD-WAR-ERA FUEL STORAGE BASIN SUPERSTRUCTURE LADEN WITH ASBESTOS

    SciTech Connect

    LLOYD ER; ORGILL TK; DAGAN EB

    2008-11-25

    The K East (KE) Basin facilities are located near the north end of the Hanford Site's 100 K area. The facilities were built in 1950 as part of the KE Reactor complex and constructed within 400 meters of the Columbia River, which is the largest river in the Pacific Northwest and by volume the fourth largest river in the United States. The basin, located adjacent to the reactor, was used for the underwater storage of irradiated nuclear fuel discharged from the reactor. The basin was covered by a superstructure comprising steel columns and beams, concrete, and cement asbestos board (CAB) siding. The project's mission was to complete demolition of the structure over the K East basin within six months of tumover from facility deactivation activities. The demolition project team implemented open-air demolition techniques to demolish the facility to slab-on-grade. Several innovative techniques were used to control contamination and maintain contamination control within the confines of the demolition exclusion zone. The techniques, which focused on a defense-in-depth approach, included spraying fixatives on interior and exterior surfaces before demolition began; applying fixatives; misting using a fine spray of water during demolition; and demolishing the facility systematically. Another innovation that aided demolition was to demolish the building with the non-friable CAB remaining in place. The CAB siding covered the exterior of the building, portions of the interior walls, and was an integral part of the multiple layered roof. The project evaluated the risks involved in removing the CAB material in a radiologically contaminated environment and determined that radiological dose rates and exposure to radiological contamination and industrial hazards would be significantly reduced by removing the CAB during demolition using heavy equipment. The ability to perform this demolition safely and without spreading contamination (radiological or asbestos) demonstrates that similar

  8. 46 CFR 32.56-20 - Insulation of exterior boundaries: Superstructures and deckhouses-T/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Insulation of exterior boundaries: Superstructures and deckhouses-T/ALL. 32.56-20 Section 32.56-20 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK... a Keel Laying Date On or After January 1, 1975 § 32.56-20 Insulation of exterior...

  9. 46 CFR 32.56-20 - Insulation of exterior boundaries: Superstructures and deckhouses-T/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Insulation of exterior boundaries: Superstructures and deckhouses-T/ALL. 32.56-20 Section 32.56-20 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK... a Keel Laying Date On or After January 1, 1975 § 32.56-20 Insulation of exterior...

  10. 46 CFR 32.56-20 - Insulation of exterior boundaries: Superstructures and deckhouses-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Insulation of exterior boundaries: Superstructures and deckhouses-T/ALL. 32.56-20 Section 32.56-20 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK... a Keel Laying Date On or After January 1, 1975 § 32.56-20 Insulation of exterior...

  11. 46 CFR 32.56-20 - Insulation of exterior boundaries: Superstructures and deckhouses-T/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Insulation of exterior boundaries: Superstructures and deckhouses-T/ALL. 32.56-20 Section 32.56-20 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK... a Keel Laying Date On or After January 1, 1975 § 32.56-20 Insulation of exterior...

  12. 46 CFR 32.56-20 - Insulation of exterior boundaries: Superstructures and deckhouses-T/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Insulation of exterior boundaries: Superstructures and deckhouses-T/ALL. 32.56-20 Section 32.56-20 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK... a Keel Laying Date On or After January 1, 1975 § 32.56-20 Insulation of exterior...

  13. Light-concentrating plasmonic Au superstructures with significantly visible-light-enhanced catalytic performance.

    PubMed

    Yang, Jinhu; Li, Ying; Zu, Lianhai; Tong, Lianming; Liu, Guanglei; Qin, Yao; Shi, Donglu

    2015-04-22

    Noble metals are well-known for their surface plasmon resonance effect that enables strong light absorption typically in the visible regions for gold and silver. However, unlike semiconductors, noble metals are commonly considered incapable of catalyzing reactions via photogenerated electron-hole pairs due to their continuous energy band structures. So far, photonically activated catalytic system based on pure noble metal nanostructures has seldom been reported. Here, we report the development of three different novel plasmonic Au superstructures comprised of Au nanoparticles, multiple-twinned nanoparticles and nanoworms assembling on the surfaces of SiO2 nanospheres respectively via a well-designed synthetic strategy. It is found that these novel Au superstructures show enhanced broadband visible-light absorption due to the plasmon resonance coupling within the superstructures, and thus can effectively focus the energy of photon fluxes to generate much more excited hot electrons and holes for promoting catalytic reactions. Accordingly, these Au superstructures exhibit significantly visible-light-enhanced catalytic efficiency (up to ∼264% enhancement) for the commercial reaction of p-nitrophenol reduction. PMID:25840556

  14. Effective properties of superstructured hyperbolic metamaterials: How to beat the diffraction limit at large focal distance

    NASA Astrophysics Data System (ADS)

    Centeno, Emmanuel; Moreau, Antoine

    2015-07-01

    Superstructured hyperbolic metamaterials (HMs) have been recently introduced to realize media with effective index -1 with the ultimate goal of designing flat lenses of super-resolution power for optical imaging applications. In this work, we analyze the impact on their effective optical properties of defect metallic layers periodically added in HMs. The effective index and losses are systematically calculated in both homogenization and diffractive regimes and with respect to the ratio of dielectric and metallic layers. Although the superstructuring can dramatically decrease the effective losses, we demonstrate that the extent of the hyperbolic dispersion curve in k space plays an even more fundamental role for breaking the diffraction limit. Optimized superstructured HMs working in a regime between the homogenization and diffractive regimes are shown to present simultaneously low effective losses and a high optical resolution for visible light. These superstructured HMs present an effective index of -5 and extend the subwavelength focalization distance up to 2 λ , which is twice as large as for regular HMs.

  15. Interplay between intercalated oxygen superstructures and monolayer h -BN on Cu(100)

    DOE PAGESBeta

    Ma, Chuanxu; Park, Jewook; Liu, Lei; Kim, Yong-Sung; Yoon, Mina; Baddorf, Arthur P.; Gu, Gong; Li, An-Ping

    2016-08-18

    The confinement effect of intercalated atoms in van der Waals heterostructures can lead to interesting interactions between the confined atoms or molecules and the overlaying two-dimensional (2D) materials. In this paper, we report the formation of ordered Cu(100) p(2×2) oxygen superstructures by oxygen intercalation under the monolayer hexagonal boron nitride (h-BN) on Cu after annealing. By using scanning tunneling microscopy and x-ray photoelectron spectroscopy, we identify the superstructure and reveal its roles in passivating the exposed Cu surfaces, decoupling h-BN and Cu, and disintegrating h-BN monolayers. The oxygen superstructure appears as a 2D pattern on the exposed Cu surface ormore » quasi-1D stripes of paired oxygen intercalated in the interface of h-BN and Cu predominantly oriented along the moiré modulations. The oxygen superstructure is shown to etch the overlaying h-BN monolayer in a thermal annealing process. After extended annealing, the h-BN monolayer disintegrates into nanoislands with zigzag edges. Finally, we discuss the implications of these findings on the stability and oxidation resistance of h-BN and relate them to challenges in process integration and 2D heterostructures.« less

  16. 9. WEST SIDE, TEST STAND AND SUPERSTRUCTURE. TEST STAND 1B ...

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

    9. WEST SIDE, TEST STAND AND SUPERSTRUCTURE. TEST STAND 1-B IN DISTANCE. Looking east. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  17. VIEW OF BRIDGE SUPERSTRUCTURE PIER “IV” AND UNDERSIDE OF RAILROAD ...

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

    VIEW OF BRIDGE SUPERSTRUCTURE PIER “IV” AND UNDERSIDE OF RAILROAD AND HIGHWAY SPAN LOOKING NORTHWEST AND UP. - Huey P. Long Bridge, Spanning Mississippi River approximately midway between nine & twelve mile points upstream from & west of New Orleans, Jefferson, Jefferson Parish, LA

  18. Efficacy of standard glucose-based and reduced-osmolarity maltodextrin-based oral rehydration solutions: effect of sugar malabsorption.

    PubMed Central

    el-Mougi, M.; Hendawi, A.; Koura, H.; Hegazi, E.; Fontaine, O.; Pierce, N. F.

    1996-01-01

    Previously we reported that standard oral rehydration salts (ORS) solution is not as effective as a reduced-osmolarity glucose-based ORS for the treatment of children with acute noncholera diarrhoea: with standard ORS the diarrhoea lasts longer, stool output is greater, serum sodium is higher, and there is more need for supplemental intravenous infusion. We studied a reduced-osmolarity maltodextrin (MD)-based ORS to determine whether it had similar benefits, and also the effect of sugar malabsorption on the efficacy of standard and MD-based ORS. A total of 90 boys aged 3-24 months with acute noncholera diarrhoea and moderate dehydration were randomly assigned to either standard ORS (glucose 20 g/l, osmolarity 311 mmol/l) or MD-ORS (MD 50 g/l, osmolarity 227 mmol/l). There were no differences in treatment results. Some 46% of subjects had a high total stool output (> 300 g/kg), which was unrelated to the type of ORS given. High stool output was significantly associated with a longer duration of diarrhoea (33 vs. 15 hours; P < 0.001), a persistently elevated serum sodium (149 vs. 144 mmol/l at 24 h; P < 0.02), the need for intravenous infusion (11/41 vs. 0/48; P < 0.002), and an increase in faecal reducing substances (10.8 vs. 3.4 g/l at 24 h; P < 0.001). We conclude that some children given standard ORS develop osmotic diarrhoea owing to the combined effect of transient sugar malabsorption and slight hypertonicity of the ORS. Earlier studies show that this adverse outcome can largely be avoided when extra water is given in reduced-osmolarity glucose-based ORS. Reduced osmolarity has no benefit, however, when glucose is replaced by maltodextrin, probably because the sugars released by hydrolysis of MD, when malabsorbed, raise the intraluminal osmolarity to equal or exceed that of standard ORS. Thus, reduced-osmolarity glucose-based ORS is superior to both standard ORS and reduced-osmolarity solutions based on maltodextrin and probably other complex carbohydrates

  19. Unknown Aspects of Self-Assembly of PbS Microscale Superstructures

    PubMed Central

    Querejeta-Fernández, Ana; Hernández-Garrido, Juan C.; Yang, Hengxi; Zhou, Yunlong; Varela, Aurea; Parras, Marina; Calvino-Gámez, José J.; González-Calbet, Jose M.; Green, Peter F.; Kotov, Nicholas A.

    2012-01-01

    A lot of interesting and sophisticated examples of nanoparticle (NP) self-assembly (SA) are known. From both fundamental and technological standpoints this field requires advancements in three principle directions: a) understanding the mechanism and driving forces of three-dimensional (3D) SA with both nano- and micro-levels of organization; b) understanding of disassembly/deconstruction processes; and c) finding synthetic methods of assembly into continuous superstructures without insulating barriers. From this perspective, we investigated the formation of well-known star-like PbS superstructures and found a number of previously unknown or overlooked aspects that can advance the knowledge of NP self-assembly in these three directions. The primary one is that the formation of large seemingly monocrystalline PbS superstructures with multiple levels of octahedral symmetry can be explained only by SA of small octahedral NPs. We found five distinct periods in the formation PbS hyperbranched stars: 1) nucleation of early PbS NPs with an average diameter of 31 nm; 2) assembly into 100–500 nm octahedral mesocrystals; 3) assembly into 1000–2500 nm hyperbranched stars; 4) assembly and ionic recrystallization into six-arm rods accompanied by disappearance of fine nanoscale structure; 5) deconstruction into rods and cubooctahedral NPs. The switches in assembly patterns between the periods occur due to variable dominance of pattern–determining forces that include vander Waals and electrostatic (charge-charge, dipole-dipole, and polarization) interactions. The superstructure deconstruction is triggered by chemical changes in the deep eutectic solvent (DES) used as the media. PbS superstructures can be excellent models for fundamental studies of nanoscale organization and SA manufacturing of (opto)electronics and energy harvesting devices which require organization of PbS components at multiple scales. PMID:22515512

  20. Unknown aspects of self-assembly of PbS microscale superstructures.

    PubMed

    Querejeta-Fernández, Ana; Hernández-Garrido, Juan C; Yang, Hengxi; Zhou, Yunlong; Varela, Aurea; Parras, Marina; Calvino-Gámez, José J; González-Calbet, Jose M; Green, Peter F; Kotov, Nicholas A

    2012-05-22

    A lot of interesting and sophisticated examples of nanoparticle (NP) self-assembly (SA) are known. From both fundamental and technological standpoints, this field requires advancements in three principle directions: (a) understanding the mechanism and driving forces of three-dimensional (3D) SA with both nano- and microlevels of organization; (b) understanding disassembly/deconstruction processes; and (c) finding synthetic methods of assembly into continuous superstructures without insulating barriers. From this perspective, we investigated the formation of well-known star-like PbS superstructures and found a number of previously unknown or overlooked aspects that can advance the knowledge of NP self-assembly in these three directions. The primary one is that the formation of large seemingly monocrystalline PbS superstructures with multiple levels of octahedral symmetry can be explained only by SA of small octahedral NPs. We found five distinct periods in the formation PbS hyperbranched stars: (1) nucleation of early PbS NPs with an average diameter of 31 nm; (2) assembly into 100-500 nm octahedral mesocrystals; (3) assembly into 1000-2500 nm hyperbranched stars; (4) assembly and ionic recrystallization into six-arm rods accompanied by disappearance of fine nanoscale structure; (5) deconstruction into rods and cuboctahedral NPs. The switches in assembly patterns between the periods occur due to variable dominance of pattern-determining forces that include van der Waals and electrostatic (charge-charge, dipole-dipole, and polarization) interactions. The superstructure deconstruction is triggered by chemical changes in the deep eutectic solvent (DES) used as the media. PbS superstructures can be excellent models for fundamental studies of nanoscale organization and SA manufacturing of (opto)electronics and energy-harvesting devices which require organization of PbS components at multiple scales. PMID:22515512

  1. Superstructure-based optimal design of PSA cycles for post-combustion CO2 capture

    SciTech Connect

    Agarwal, A.; Biegler, L.; Zitney, S.

    2009-07-01

    Recent developments have shown pressure/vacuum swing adsorption (PSA/VSA) to be a promising option to effectively capture CO2 from flue gas streams. In most commercial PSA cycles, the weakly adsorbed component in the mixture is the desired product, and enriching the strongly adsorbed CO2 is not a concern. Thus, it is necessary to develop PSA processes specifically targeted to obtain pure strongly adsorbed component. So far, no systematic methodology has been suggested in the literature to design PSA cycles for high purity CO2 capture. This study addresses this need and presents a systematic optimization-based formulation to synthesize PSA cycles. In particular, a novel PSA superstructure is presented to design optimal PSA cycle configurations and evaluate CO2 capture strategies. The superstructure is rich enough to predict a number of different PSA operating steps. The bed connections in the superstructure are governed by timedependent control variables, which can be varied to realize most PSA operating steps. An optimal sequence of operating steps is achieved through the formulation of an optimal control problem with the partial differential and algebraic equations of the PSA system and the cyclic steady state condition. The superstructure approach is demonstrated for case studies related to post-combustion CO2 capture. In particular, optimal PSA cycles were synthesized which maximize CO2 recovery for a given purity, and minimize overall power consumption. The results show the potential of the superstructure to predict PSA cycles with up to 98% purity and recovery of CO2. Moreover, for recovery of around 85% and purity of over 90%, these cycles can recover CO2 from atmospheric flue gas with a low power consumption of 465 kWh/tonne CO2. The approach presented is, therefore, very promising and quite useful for evaluating the suitability of different adsorbents, feedstocks and operating strategies for PSA, and assessing its usefulness for CO2 capture.

  2. Degradation of naled and dichlorvos promoted by reduced sulfur species in well-defined anoxic aqueous solutions.

    PubMed

    Gan, Qiu; Singh, Raphael M; Jans, Urs

    2006-02-01

    This work examines the reaction of reduced sulfur species (e.g., bisulfide, thiosulfate, thiophenolate) with naled, a registered insecticide, in well-defined anoxic aqueous solutions at 5 degrees C. High concentrations of reduced sulfur species can occur in the porewater of sediments and in anoxic subregions of estuaries. The dominanttransformation product from the reaction of naled with reduced sulfur species is dichlorvos, which indicates that debromination is the major reaction pathway. Dichlorvos is also a registered insecticide which is more toxic than naled. The second-order rate constants for reaction of naled with bisulfide and thiophenolate at 5 degrees C are 10.2 +/- 0.4 M(-1) s(-1) and 27.3 +/- 0.9 M(-1) s(-1), respectively, while the second-order rate constant for the reaction of naled with hydrogen sulfide and thiophenol are not significantly different from zero. The second-order rate constant of the reaction of naled with thiosulfate at 5 degrees C is 5.0 +/- 0.3 M(-1) s(-1). In contrast, the second-order rate constant of the reaction of dichlorvos with bisulfide at 25 degrees C is (3.3 +/- 0.1) x 10(-3) M(-1) s(-1). The activation parameters of the reaction of naled with bisulfide were also determined from the measured second-order rate constants over a temperature range. The results indicate that reduced sulfur species can play a very important role in the transformation of naled and dichlorvos in the coastal marine environment. It can be expected that in the presence of reduced sulfur species, naled is almost immediately transformed into the more toxic dichlorvos, which has an expected half-life of 4 days to weeks. PMID:16509318

  3. The Compatible Solute Ectoine Reduces the Exacerbating Effect of Environmental Model Particles on the Immune Response of the Airways

    PubMed Central

    Gotić, Marijan

    2014-01-01

    Exposure of humans to particulate air pollution has been correlated with the incidence and aggravation of allergic airway diseases. In predisposed individuals, inhalation of environmental particles can lead to an exacerbation of immune responses. Previous studies demonstrated a beneficial effect of the compatible solute ectoine on lung inflammation in rats exposed to carbon nanoparticles (CNP) as a model of environmental particle exposure. In the current study we investigated the effect of such a treatment on airway inflammation in a mouse allergy model. Ectoine in nonsensitized animals significantly reduced the neutrophilic lung inflammation after CNP exposure. This effect was accompanied by a reduction of inflammatory factors in the bronchoalveolar lavage. Reduced IL-6 levels in the serum also indicate the effects of ectoine on systemic inflammation. In sensitized animals, an aggravation of the immune response was observed when animals were exposed to CNP prior to antigen provocation. The coadministration of ectoine together with the particles significantly reduced this exacerbation. The data indicate the role of neutrophilic lung inflammation in the exacerbation of allergic airway responses. Moreover, the data suggest to use ectoine as a preventive treatment to avoid the exacerbation of allergic airway responses induced by environmental air pollution. PMID:24822073

  4. Self-Assembled Hierarchical Superstructures from the Benzene-1,3,5-Tricarboxamide Supramolecules for the Fabrication of Remote-Controllable Actuating and Rewritable Films.

    PubMed

    Choi, Yu-Jin; Kim, Dae-Yoon; Park, Minwook; Yoon, Won-Jin; Lee, Yumin; Hwang, Joo-Kyoung; Chiang, Yeo-Wan; Kuo, Shiao-Wei; Hsu, Chih-Hao; Jeong, Kwang-Un

    2016-04-13

    The well-defined hierarchical superstructures constructed by the self-assembly of programmed supramolecules can be organized for the fabrication of remote-controllable actuating and rewritable films. To realize this concept, we newly designed and synthesized a benzene-1,3,5-tricarboxamide (BTA) derivative (abbreviated as BTA-3AZO) containing photoresponsive azobenzene (AZO) mesogens on the periphery of the BTA core. BTA-3AZO was first self-assembled to nanocolumns mainly driven by the intermolecular hydrogen-bonds between BTA cores, and these self-assembled nanocolumns were further self-organized laterally to form the low-ordered hexagonal columnar liquid crystal (LC) phase below the isotropization temperature. Upon cooling, a lamello-columnar crystal phase emerged at room temperature via a highly ordered lamello-columnar LC phase. The three-dimensional (3D) organogel networks consisted of fibrous and lamellar superstructures were fabricated in the BTA-3AZO cyclohexane-methanol solutions. By tuning the wavelength of light, the shape and color of the 3D networked thin films were remote-controlled by the conformational changes of azobenzene moieties in the BTA-3AZO. The demonstrations of remote-controllable 3D actuating and rewritable films with the self-assembled hierarchical BTA-3AZO thin films can be stepping stones for the advanced flexible optoelectronic devices. PMID:27020653

  5. Solution structure of reduced monomeric Q133M2 copper, zinc superoxide dismutase (SOD). Why is SOD a dimeric enzyme?.

    PubMed

    Banci, L; Benedetto, M; Bertini, I; Del Conte, R; Piccioli, M; Viezzoli, M S

    1998-08-25

    Copper, zinc superoxide dismutase is a dimeric enzyme, and it has been shown that no cooperativity between the two subunits of the dimer is operative. The substitution of two hydrophobic residues, Phe 50 and Gly 51, with two Glu's at the interface region has disrupted the quaternary structure of the protein, thus producing a soluble monomeric form. However, this monomeric form was found to have an activity lower than that of the native dimeric species (10%). To answer the fundamental question of the role of the quaternary structure in the catalytic process of superoxide dismutase, we have determined the solution structure of the reduced monomeric mutant through NMR spectroscopy. Another fundamental issue with respect to the enzymatic mechanism is the coordination of reduced copper, which is the active center. The three-dimensional solution structure of this 153-residue monomeric form of SOD (16 kDa) has been determined using distance and dihedral angle constraints obtained from 13C, 15N triple-resonance NMR experiments. The solution structure is represented by a family of 36 structures, with a backbone rmsd of 0.81 +/- 0.13 A over residues 3-150 and of 0.56 +/- 0.08 A over residues 3-49 and 70-150. This structure has been compared with the available X-ray structures of reduced SODs as well as with the oxidized form of human and bovine isoenzymes. The structure contains the classical eight-stranded Greek key beta-barrel. In general, the backbone and the metal sites are not affected much by the monomerization, except in the region involved in the subunit-subunit interface in the dimeric protein, where a large disorder is present. Significative changes are observed in the conformation of the electrostatic loop, which forms one side of the active site channel and which is fundamental in determining the optimal electrostatic potential for driving the superoxide anions to the copper site which is the rate-limiting step of the enymatic reaction under nonsaturating

  6. Searching for crystallographic superstructures in kappa-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]Br.

    SciTech Connect

    Wolter, A. U. B.; Feyerherm, R.; Dudzik, E.; Sullow, S.; Strack, Ch.; Lang, M.; Schweitzer, D.; Schlueter, J. A.; Materials Science Division; Inst Physcal Condensed Matter; Helmholtz-Centre Berlin for Materials and Energy; Leibniz Inst. Solid State Research; J. W. Goethe-Univ.; Univ. Stuttgart

    2010-01-01

    To resolve a superstructure formation previously reported for the organic superconductor {kappa}-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]Br, we present synchrotron x-ray diffraction experiments carried out at the MAGS beamline at BESSY, Helmholtz-Centre Berlin. Surprisingly, in our low temperature (28 K) experiments, when searching k-space at (h 0 3.5), h = 7, 8 and (h 0 0.5), h = 5, 7, for none of these spots we could detect scattering intensity associated to a superstructure formation, in contradiction to previous reports. Our data suggest that details of the structural properties of {kappa}-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]Br - such as superstructure formation - sensitively depend on sample handling, e.g., cooling rates (in our case 4 K/min), or thermal cycling. A direct relationship between superstructure formation and terminal ethylene group ordering cannot be verified, disproving proposals put forth previously.

  7. Direct Fabrication of Free-Standing MOF Superstructures with Desired Shapes by Micro-Confined Interfacial Synthesis.

    PubMed

    Kim, Jin-Oh; Min, Kyoung-Ik; Noh, Hyunwoo; Kim, Dong-Hwi; Park, Soo-Young; Kim, Dong-Pyo

    2016-06-13

    Recently, metal-organic frameworks (MOFs) with multifunctional pore chemistry have been intensively investigated for positioning the desired morphology at specific locations onto substrates for manufacturing devices. Herein, we develop a micro-confined interfacial synthesis (MIS) approach for fabrication of a variety of free-standing MOF superstructures with desired shapes. This approach for engineering MOFs provides three key features: 1) in situ synthesis of various free-standing MOF superstructures with controlled compositions, shape, and thickness using a mold membrane; 2) adding magnetic functionality into MOF superstructures by loading with Fe3 O4 nanoparticles; 3) transferring the synthesized MOF superstructural array on to flat or curved surface of various substrates. The MIS route with versatile potential opens the door for a number of new perspectives in various applications. PMID:27140805

  8. Highly Ordered Single Crystalline Nanowire Array Assembled Three-Dimensional Nb3O7(OH) and Nb2O5 Superstructures for Energy Storage and Conversion Applications.

    PubMed

    Zhang, Haimin; Wang, Yun; Liu, Porun; Chou, Shu Lei; Wang, Jia Zhao; Liu, Hongwei; Wang, Guozhong; Zhao, Huijun

    2016-01-26

    Three-dimensional (3D) metal oxide superstructures have demonstrated great potentials for structure-dependent energy storage and conversion applications. Here, we reported a facile hydrothermal method for direct growth of highly ordered single crystalline nanowire array assembled 3D orthorhombic Nb3O7(OH) superstructures and their subsequent thermal transformation into monoclinic Nb2O5 with well preserved 3D nanowire superstructures. The performance of resultant 3D Nb3O7(OH) and Nb2O5 superstructures differed remarkably when used for energy conversion and storage applications. The thermally converted Nb2O5 superstructures as anode material of lithium-ion batteries (LiBs) showed higher capacity and excellent cycling stability compared to the Nb3O7(OH) superstructures, while directly hydrothermal grown Nb3O7(OH) nanowire superstructure film on FTO substrate as photoanode of dye-sensitized solar cells (DSSCs) without the need for further calcination exhibited an overall light conversion efficiency of 6.38%, higher than that (5.87%) of DSSCs made from the thermally converted Nb2O5 film. The high energy application performance of the niobium-based nanowire superstructures with different chemical compositions can be attributed to their large surface area, superior electron transport property, and high light utilization efficiency resulting from a 3D superstructure, high crystallinity, and large sizes. The formation process of 3D nanowire superstructures before and after thermal treatment was investigated and discussed based on our theoretical and experimental results. PMID:26579783

  9. Multi-component superstructures self-assembled from nanocrystal building blocks

    NASA Astrophysics Data System (ADS)

    Tan, Rui; Zhu, Hua; Cao, Can; Chen, Ou

    2016-05-01

    More than three decades of intensive study to make high-quality nanocrystals have created a unique toolbox for building multi-component superstructures, which have been recognized as a new generation of metamaterials important to both fundamental sciences and applied technologies. This minireview summarizes recent advances in this exciting field. We will focus our discussion on the synthetic strategies and superstructures of this multi-component metamaterial, and highlight their novel properties and potential applications. Additionally, some perspectives on possible developments in this field are offered at the end of this review. We hope that this minireview will both inform and stimulate research interests for the design and fabrication of these nanocrystal-based multi-component metamaterials for diverse applications in the future.

  10. Observation of the Early Structural Changes Leading to the Formation of Protein Superstructures.

    PubMed

    Foderà, Vito; Vetri, Valeria; Wind, Thea S; Noppe, Wim; Cornett, Claus; Donald, Athene M; Morozova-Roche, Ludmilla A; Vestergaard, Bente

    2014-09-18

    Formation of superstructures in protein aggregation processes has been indicated as a general pathway for several proteins, possibly playing a role in human pathologies. There is a severe lack of knowledge on the origin of such species in terms of both mechanisms of formation and structural features. We use equine lysozyme as a model protein, and by combining spectroscopic techniques and microscopy with X-ray fiber diffraction and ab initio modeling of Small Angle X-ray Scattering data, we isolate the partially unfolded state from which one of these superstructures (i.e., particulate) originates. We reveal the low-resolution structure of the unfolded state and its mechanism of formation, highlighting the physicochemical features and the possible pathway of formation of the particulate structure. Our findings provide a novel detailed knowledge of such a general and alternative aggregation pathway for proteins, this being crucial for a basic and broader understanding of the aggregation phenomena. PMID:26276341

  11. Multi-component superstructures self-assembled from nanocrystal building blocks.

    PubMed

    Tan, Rui; Zhu, Hua; Cao, Can; Chen, Ou

    2016-05-21

    More than three decades of intensive study to make high-quality nanocrystals have created a unique toolbox for building multi-component superstructures, which have been recognized as a new generation of metamaterials important to both fundamental sciences and applied technologies. This minireview summarizes recent advances in this exciting field. We will focus our discussion on the synthetic strategies and superstructures of this multi-component metamaterial, and highlight their novel properties and potential applications. Additionally, some perspectives on possible developments in this field are offered at the end of this review. We hope that this minireview will both inform and stimulate research interests for the design and fabrication of these nanocrystal-based multi-component metamaterials for diverse applications in the future. PMID:27136751

  12. Constructing molecular structures on periodic superstructure of graphene/Ru(0001)

    PubMed Central

    Li, Geng; Huang, Li; Xu, Wenyan; Que, Yande; Zhang, Yi; Lu, Jianchen; Du, Shixuan; Liu, Yunqi; Gao, Hong-Jun

    2014-01-01

    We review the way to fabricate large-scale, high-quality and single crystalline graphene epitaxially grown on Ru(0001) substrate. A moiré pattern of the graphene/Ru(0001) is formed due to the lattice mismatch between graphene and Ru(0001). This superstructure gives rise to surface charge redistribution and could behave as an ordered quantum dot array, which results in a perfect template to guide the assembly of organic molecular structures. Molecules, for example iron phthalocyanine and C60, on this template show how the molecule–substrate interaction makes different superstructures. These results show the possibility of constructing ordered molecular structures on graphene/Ru(0001), which is helpful for practical applications in the future. PMID:24615151

  13. B K-Edge XANES of Superstructural Units in Borate Glasses

    SciTech Connect

    Sipr, O.; Simunek, A.; Rocca, F.

    2007-02-02

    The potential of x-ray absorption near-edge structure (XANES) spectroscopy for studying medium range order in borate glasses is assessed by theoretical modelling of the spectra. B K edge XANES is calculated in case that B atoms are located in isolated BO3 and BO4 units and in case that B atom are located in superstructural units of 9-15 atoms. It is found that boroxol ring and diborate and ditriborate superstructural units give rise to spectra which differ from spectra obtained by a mere superposition of spectra of isolated BO3 and BO4 units. On the other hand, spectra of pentaborate and triborate units do not differ significantly from spectra of isolated BO3 and BO4.

  14. The integrated Sachs-Wolfe imprint of cosmic superstructures: a problem for ΛCDM

    SciTech Connect

    Nadathur, Seshadri; Sarkar, Subir; Hotchkiss, Shaun E-mail: shaun.hotchkiss@helsinki.fi

    2012-06-01

    A crucial diagnostic of the ΛCDM cosmological model is the integrated Sachs-Wolfe (ISW) effect of large-scale structure on the cosmic microwave background (CMB). The ISW imprint of superstructures of size ∼ 100 h{sup −1}Mpc at redshift z ∼ 0.5 has been detected with > 4σ significance, however it has been noted that the signal is much larger than expected. We revisit the calculation using linear theory predictions in ΛCDM cosmology for the number density of superstructures and their radial density profile, and take possible selection effects into account. While our expected signal is larger than previous estimates, it is still inconsistent by > 3σ with the observation. If the observed signal is indeed due to the ISW effect then huge, extremely underdense voids are far more common in the observed universe than predicted by ΛCDM.

  15. Microwave-assisted synthesis of gold nanoparticles self-assembled into self-supported superstructures

    PubMed Central

    Esparza, R.; Vargas-Hernández, C.; Fernández García, M. E.; José-Yacamán, M.

    2014-01-01

    Passivated gold nanoparticles were synthesized through a microwave-assisted process in a two-phase system, in the presence of 1-dodecanethiol. An average particle size of 1.8 nm of the gold nanoparticles obtained and 0.35 S.D. was determined through HRTEM and STEM analysis. It was observed that these nanoparticles spontaneously self-assemble into self-supported superstructures of 1 μm in diameter avg and 400 nm thickness, yielding an off-white powder which can be handled as a simple powder. XRD analysis indicates that n-alkanethiol molecules used as a passivating compound, besides protecting against crystal growth, interact to form cubic ordered arrays between the nanoparticles. This interaction leads to the superstructure formation, with an average distance between nanoparticles in the array, of 3.56 nm. Theoretical calculations and molecular dynamics simulations were performed to analyze the resulting structure. PMID:22398420

  16. Peptide-based methods for assembling and controlling the morphologies, metrics, and properties of gold nanoparticle superstructures

    NASA Astrophysics Data System (ADS)

    Zhang, Chen

    This dissertation describes new peptide-based methods for assembling and controlling the morphologies, metrics, and properties of gold nanoparticle superstructures. The aim of this research is to develop the peptide-based method by modifying the peptide sequences and controlling the reaction conditions for the synthesis and assembly of gold nanoparticle superstructures to achieve reliable control over their morphology and metrics, and furthermore study their properties and applications. With this goal in mind, the C-terminus of a gold-binding peptide was modified with different numbers of hydrophobic phenylalanines to affect peptide assembly and ultimately nanoparticle assembly. The addition of hydrophobic phenylalanines to the C-terminus of peptide conjugates promoted fiber bundling which in turn lead to the formation of thick or intertwined 1-D nanoparticle superstructures. Furthermore, I prepared spherical gold nanoparticle superstructures with varied diameters (˜40nm, ˜75nm, and ˜150nm) and visible to near-infrared optical properties by using a single peptide conjugate molecule yet varied reaction conditions. Theoretical simulation and experiment were coupled to further understand their optical properties. Finally, I studied and demonstrated the drug storage and release properties of hollow spherical gold nanoparticle superstructures; this was the first demonstrated application of this class of nanoparticle superstructure.

  17. Enigmatic Cranial Superstructures among Chamorro Ancestors from the Mariana Islands: Gross Anatomy and Microanatomy

    PubMed Central

    Heathcote, Gary M.; Bromage, Timothy G.; Sava, Vincent J.; Hanson, Douglas B.; Anderson, Bruce E.

    2014-01-01

    This study focuses on the gross anatomy, anatomic relations, microanatomy, and meaning of three enigmatic, geographically-patterned, quasi-continuous superstructures of the posterior cranium. Collectively known as occipital superstructures (OSS), these traits are the occipital torus tubercle (TOT), retromastoid process (PR), and posterior supramastoid tubercle (TSP). When present, TOT, PR and TSP develop at posterior cranial attachment sites of the upper trapezius, superior oblique and sternocleidomastoid muscles, respectively. Marked expression and co-occurrence of these OSS are virtually circumscribed within Oceania and reach highest recorded frequencies in proto-historic Chamorros (CHamoru) of the Mariana Islands. Prior to undertaking scanning electron microscopy (SEM) work, our working multifactorial model for OSS development was that early-onset, long-term, chronic activity-related microtrauma at enthesis sites led to exuberant reactive or reparative responses in a substantial minority of genetically predisposed (and mostly male) individuals. SEM imaging, however, reveals topographic patterning that questions, but does not negate, activity-induction of these superstructures. While OSS appear macroscopically as relatively large and discrete phenomena, SEM findings reveal a unique, widespread and seemingly systemic distribution of structures over the occipital surface that have the appearance of OSS microforms. Nevertheless, apparent genetic underpinnings, anatomic relationships with muscle entheses, and positive correlation of OSS development with humeral robusticity continue to suggest that these superstructures have potential to at once bear witness to Chamorro population history and inform osteobiographical constructions of chronic activity patterns in individuals bearing them. Further work is outlined that would illuminate the proximate and ultimate meanings of OSS. PMID:24753475

  18. Cryo-transmission electron microscopy of a superstructure of fluid dioleoylphosphatidylcholine (DOPC) membranes.

    PubMed Central

    Klösgen, B; Helfrich, W

    1997-01-01

    Using cryo-transmission electron microscopy, we have obtained abundant and reproducible evidence for a superstructure of dioleoylphosphatidylcholine (DOPC) bilayers. Dispersions of vesicles were prepared by gentle shaking of a 2% suspension of DOPC in water followed in part by extrusion through a porous technical membrane. Sampling and cryofixation took place at various times within 3 weeks after the preparation. From the micrographs we infer that the small fraction of vesicles enclosing one another develop passages (connections) between the bilayers. In contrast, the superstructure is basically a feature of disconnected membranes. Among its modifications are isolated membrane bends or folds and a grainy membrane texture with a minimal grain spacing of 4-6 nm. In the extruded dispersions the passages and the superstructure seem to be formed mostly within the first day. The fraction of smooth and unilamellar vesicles is large at all times and in all dispersions. Images FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 6 FIGURE 7 FIGURE 8 FIGURE 9 FIGURE 11 FIGURE 12 FIGURE 13 FIGURE 14 FIGURE 15 FIGURE 16 FIGURE 17 FIGURE 18 FIGURE 19 PMID:9414216

  19. Superstructure of TiO2 Crystalline Nanoparticles Yields Effective Conduction Pathways for Photogenerated Charges.

    PubMed

    Bian, Zhenfeng; Tachikawa, Takashi; Majima, Tetsuro

    2012-06-01

    Materials with intricate nanostructures display fascinating properties, which have inspired extensive research on the synthesis of materials with controlled structures. In this study, we investigated the properties of superstructures of TiO2 to understand the inter-relationship between structural ordering and photocatalytic performance. The nanoplate anatase TiO2 mesocrystals were chosen as the typical investigation objects, which were newly synthesized by a topotactic structural transformation. The TiO2 mesocrystals displayed the superstructure of crystallographically ordered alignment of anatase TiO2 nanocrystals with high surface area and large high-energy surface {001} planes exposed. The photoconductive atomic force microscopy and time-resolved diffuse reflectance spectroscopy were utilized to determine the charge transport properties of TiO2 mesocrystals, and their features were highlighted by a comparison with reference TiO2 samples, for example, anatase TiO2 nanocrystals with similar surface area and single crystal structure. Consequently, it was found for the first time that such a superstructure of TiO2 could largely enhance charge separation and had remarkably long-lived charges, thereby exhibiting greatly increased photoconductivity and photocatalytic activity. PMID:26285616

  20. Evolution of Moiré Profiles from van der Waals Superstructures of Boron Nitride Nanosheets.

    PubMed

    Liao, Yunlong; Cao, Wei; Connell, John W; Chen, Zhongfang; Lin, Yi

    2016-01-01

    Two-dimensional (2D) van der Waals (vdW) superstructures, or vdW solids, are formed by the precise restacking of 2D nanosheet lattices, which can lead to unique physical and electronic properties that are not available in the parent nanosheets. Moiré patterns formed by the crystalline mismatch between adjacent nanosheets are the most direct features for vdW superstructures under microscopic imaging. In this article, transmission electron microscopy (TEM) observation of hexagonal Moiré patterns with unusually large micrometer-sized lateral areas (up to ~1 μm(2)) and periodicities (up to ~50 nm) from restacking of liquid exfoliated hexagonal boron nitride nanosheets (BNNSs) is reported. This observation was attributed to the long range crystallinity and the contaminant-free surfaces of these chemically inert nanosheets. Parallel-line-like Moiré fringes with similarly large periodicities were also observed. The simulations and experiments unambiguously revealed that the hexagonal patterns and the parallel fringes originated from the same rotationally mismatched vdW stacking of BNNSs and can be inter-converted by simply tilting the TEM specimen following designated directions. This finding may pave the way for further structural decoding of other 2D vdW superstructure systems with more complex Moiré images. PMID:27188697

  1. Superstructure formation and variation in Ni-GDC cermet anodes in SOFC.

    PubMed

    Li, Zhi-Peng; Mori, Toshiyuki; Auchterlonie, Graeme John; Zou, Jin; Drennan, John

    2011-05-28

    The microstructures and spatial distributions of constituent elements at the anode in solid oxide fuel cells (SOFCs) have been characterized by analytical transmission electron microscopy (TEM). High resolution TEM observations demonstrate two different types of superstructure formation in grain interiors and at grain boundaries. Energy-filtered TEM elemental imaging qualitatively reveals that mixture zones exist at metal-ceramic grain boundaries, which is also quantitatively verified by STEM energy dispersive X-ray spectroscopy. It was apparent that both metallic Ni and the rare-earth elements Ce/Gd in gadolinium-doped ceria can diffuse into each other with equal diffusion lengths (about 100 nm). This will lead to the existence of mutual diffusion zones at grain boundaries, accompanied by a change in the valence state of the diffusing ions, as identified by electron energy-loss spectroscopy (EELS). Such mutual diffusion is believed to be the dominant factor that gives rise to superstructure formation at grain boundaries, while a different superstructure is formed at grain interiors, as a consequence solely of the reduction of Ce(4+) to Ce(3+) during H(2) treatment. This work will enhance the fundamental understanding of microstructural evolution at the anode, correlating with advancements in sample preparation in order to improve the performance of SOFC anodes. PMID:21494741

  2. Periodic Modulation of the Doping Level in Striped MoS2 Superstructures.

    PubMed

    Zhou, Xiebo; Shi, Jianping; Qi, Yue; Liu, Mengxi; Ma, Donglin; Zhang, Yu; Ji, Qingqing; Zhang, Zhepeng; Li, Cong; Liu, Zhongfan; Zhang, Yanfeng

    2016-03-22

    Although the recently discovered monolayer transition metal dichalcogenides exhibit novel electronic and optical properties, fundamental physical issues such as the quasiparticle bandgap tunability and the substrate effects remain undefined. Herein, we present the report of a quasi-one-dimensional periodically striped superstructure for monolayer MoS2 on Au(100). The formation of the unique striped superstructure is found to be mainly modulated by the symmetry difference between MoS2 and Au(100) and their lattice mismatch. More intriguingly, we find that the monolayer MoS2 is heavily n-doped on the Au(100) facet with a bandgap of 1.3 eV, and the Fermi level is upshifted by ∼0.10 eV on the ridge (∼0.2 eV below the conduction band) in contrast to the valley regions (∼0.3 eV below the conduction band) of the striped patterns after high-temperature sample annealing process. This tunable doping effect is considered to be caused by the different defect densities over the ridge/valley regions of the superstructure. Additionally, an obvious bandgap reduction is observed in the vicinity of the domain boundary for monolayer MoS2 on Au(100). This work should therefore inspire intensive explorations of adlayer-substrate interactions, the defects, and their effects on band-structure engineering of monolayer MoS2. PMID:26913990

  3. Right handed chiral superstructures from achiral molecules: self-assembly with a twist

    NASA Astrophysics Data System (ADS)

    Anuradha; La, Duong Duc; Al Kobaisi, Mohammad; Bhosale, Sheshanath V.

    2015-10-01

    The induction and development of chiral supramolecular structures from hierarchical self-assembly of achiral compounds is closely related to the evolution of life and the chiral amplification found in nature. Here we show that the combination of achiral tetraphenylethene (TPE) an AIE-active luminophore bearing four long alkyl chains via amide linkage allows the entire process of induction and control of supramolecular chirality into well-defined uniform right-handed twisted superstructures via solvent composition and polarity, i.e. solvophobic effect. We showed that the degree of twist and the pitch of the ribbons can be controlled to one-handed helical structure via solvophobic effects. The twisted superstructure assembly was visualised by scanning electron microscope (SEM) and transmission electron microscopy (TEM), furthermore, circular dichroism (CD) confirms used to determine controlled right-handed assembly. This controlled assembly of an AIE-active molecule can be of practical value; for example, as templates for helical crystallisation, catalysis and a chiral mechanochromic luminescent superstructure formation.

  4. Right handed chiral superstructures from achiral molecules: self-assembly with a twist

    PubMed Central

    Anuradha, A; La, Duong Duc; Al Kobaisi, Mohammad; Bhosale, Sheshanath V.

    2015-01-01

    The induction and development of chiral supramolecular structures from hierarchical self-assembly of achiral compounds is closely related to the evolution of life and the chiral amplification found in nature. Here we show that the combination of achiral tetraphenylethene (TPE) an AIE-active luminophore bearing four long alkyl chains via amide linkage allows the entire process of induction and control of supramolecular chirality into well-defined uniform right-handed twisted superstructures via solvent composition and polarity, i.e. solvophobic effect. We showed that the degree of twist and the pitch of the ribbons can be controlled to one-handed helical structure via solvophobic effects. The twisted superstructure assembly was visualised by scanning electron microscope (SEM) and transmission electron microscopy (TEM), furthermore, circular dichroism (CD) confirms used to determine controlled right-handed assembly. This controlled assembly of an AIE-active molecule can be of practical value; for example, as templates for helical crystallisation, catalysis and a chiral mechanochromic luminescent superstructure formation. PMID:26493294

  5. Evolution of Moiré Profiles from van der Waals Superstructures of Boron Nitride Nanosheets

    NASA Astrophysics Data System (ADS)

    Liao, Yunlong; Cao, Wei; Connell, John W.; Chen, Zhongfang; Lin, Yi

    2016-05-01

    Two-dimensional (2D) van der Waals (vdW) superstructures, or vdW solids, are formed by the precise restacking of 2D nanosheet lattices, which can lead to unique physical and electronic properties that are not available in the parent nanosheets. Moiré patterns formed by the crystalline mismatch between adjacent nanosheets are the most direct features for vdW superstructures under microscopic imaging. In this article, transmission electron microscopy (TEM) observation of hexagonal Moiré patterns with unusually large micrometer-sized lateral areas (up to ~1 μm2) and periodicities (up to ~50 nm) from restacking of liquid exfoliated hexagonal boron nitride nanosheets (BNNSs) is reported. This observation was attributed to the long range crystallinity and the contaminant-free surfaces of these chemically inert nanosheets. Parallel-line-like Moiré fringes with similarly large periodicities were also observed. The simulations and experiments unambiguously revealed that the hexagonal patterns and the parallel fringes originated from the same rotationally mismatched vdW stacking of BNNSs and can be inter-converted by simply tilting the TEM specimen following designated directions. This finding may pave the way for further structural decoding of other 2D vdW superstructure systems with more complex Moiré images.

  6. Energy Localization in the Ordered Condensed Systems: A 3 B Alloys With L12 Superstructure

    NASA Astrophysics Data System (ADS)

    Medvedev, N. N.; Starostenkov, M. D.; Potekaev, A. I.; Zakharov, P. V.; Markidonov, A. V.; Eremin, A. M.

    2014-07-01

    Energy localization in the ordered condensed systems is analyzed using А3В alloys with L12 superstructure. Using molecular dynamics, possible localization of phonon vibration energy in the aluminum sublattice and generation of a localized mode oscillating at a frequency belonging to the phonon spectrum energy gap and not representing a breather is considered for the ordered Pt3Al and Ni3Al alloys with L12 superstructure, which possess translational symmetry. Manifestations of anharmonicity in the atomic interactions and the relevant features of energy redistribution between sublattices of the ordered alloys are investigated. It is found out that in the ordered alloys of an A3B stoichiometry with L12 superstructure, whose phonon spectrum has a forbidden energy gap, vibrational energy can localize on the sublattice of B atoms. The alloys, found in a state of thermodynamic equilibrium at a certain temperature, are characterized by a local effect of spontaneous energy localization (the effect of energy redistribution between the lattices).

  7. Insertion approach: bolstering the reproducibility of electrochemical signal amplification via DNA superstructures.

    PubMed

    Yang, Li; Zhang, Caihua; Jiang, Hong; Li, Guijuan; Wang, Jiahai; Wang, Erkang

    2014-05-20

    For more than a decade, the backfilling approach for the immobilization of DNA probes has been routinely adopted for the construction of functional interfaces; however, reliably reproducing electrochemical signal amplification by this method is a challenge. In this research, we demonstrate that the insertion approach significantly bolsters the reproducibility of electrochemical signal amplification via DNA superstructures. The combination of the backfilling approach and the DNA superstructure formation poses a big challenge to reliably reproducing electrochemical signal amplification. In order to use the detection of Hg(2+) as a prototype of this new strategy, a thymine-rich DNA probe that is specific to mercury ion was applied in this study. The presence of Hg(2+) induces the folding of the DNA probes and inhibits the formation of DNA superstructures. By using electroactive probes ([Ru(NH3)6](3+)) that are electrostatically adsorbed onto the double strands, differential pulse voltammetry (DPV) could quantitatively confirm the presence of Hg(2+). A limit of detection (LOD) and a limit of quantification (LOQ) (LOQ) as low as 0.3 and 9.5 pM, respectively, were achieved. Furthermore, excellent selectivity and real sample analysis demonstrated the promising potential of this approach in future applications. PMID:24761933

  8. Evolution of Moiré Profiles from van der Waals Superstructures of Boron Nitride Nanosheets

    PubMed Central

    Liao, Yunlong; Cao, Wei; Connell, John W.; Chen, Zhongfang; Lin, Yi

    2016-01-01

    Two-dimensional (2D) van der Waals (vdW) superstructures, or vdW solids, are formed by the precise restacking of 2D nanosheet lattices, which can lead to unique physical and electronic properties that are not available in the parent nanosheets. Moiré patterns formed by the crystalline mismatch between adjacent nanosheets are the most direct features for vdW superstructures under microscopic imaging. In this article, transmission electron microscopy (TEM) observation of hexagonal Moiré patterns with unusually large micrometer-sized lateral areas (up to ~1 μm2) and periodicities (up to ~50 nm) from restacking of liquid exfoliated hexagonal boron nitride nanosheets (BNNSs) is reported. This observation was attributed to the long range crystallinity and the contaminant-free surfaces of these chemically inert nanosheets. Parallel-line-like Moiré fringes with similarly large periodicities were also observed. The simulations and experiments unambiguously revealed that the hexagonal patterns and the parallel fringes originated from the same rotationally mismatched vdW stacking of BNNSs and can be inter-converted by simply tilting the TEM specimen following designated directions. This finding may pave the way for further structural decoding of other 2D vdW superstructure systems with more complex Moiré images. PMID:27188697

  9. Modulated structures of Cs2HgCl4: the 5a superstructure at 185 K and the 3c superstructure at 176 K.

    PubMed

    Bagautdinov; Pilz; Ludecke; van Smaalen S

    1999-12-01

    Crystalline dicaesium mercury tetrachloride (Cs(2)HgCl(4)) is isomorphous with beta-K(2)SO(4) (space group Pnma, Z = 4) in its normal phase at room temperature. On cooling a sequence of incommensurate and commensurate superstructures occurs, below T = 221 K with modulations parallel to a*, and below 184 K with modulations along c*. The commensurately modulated structures at T = 185 K with q = (1/5)a* and at T = 176 K with q = (1/3)c* were determined using X-ray scattering with synchrotron radiation. The structure at T = 185 K has superspace group Pnma(alpha,0,0)0ss with alpha = 0.2. Lattice parameters were determined as a = 5 x 9.7729 (1), b = 7.5276 (4) and c = 13.3727 (7) Å. Structure refinements converged to R = 0.050 (R = 0.042 for 939 main reflections and R = 0.220 for 307 satellites) for the section t = 0.05 of superspace. The fivefold supercell has space group Pn2(1)a. The structure at T = 176 K has superspace group Pnma(0,0,gamma)0s0 with gamma = 1/3. Lattice parameters were determined as a = 9.789 (3), b = 7.541 (3) and c = 3 x 13.418 (4) Å. Structure refinements converged to R = 0.067 (R = 0.048 for 2130 main reflections, and R = 0.135 for 2382 satellite reflections) for the section t = 0. The threefold supercell has space group P112(1)/a. It is shown that the structures of both low-temperature phases can be characterized as different superstructures of the periodic room-temperature structure. The superstructure of the 5a-modulated phase is analysed in terms of displacements of the Cs atoms, and rotations and distortions of HgCl(4) tetrahedral groups. In the 3c-modulated phase the distortions of the tetrahedra are relaxed, but they are replaced by translations of the tetrahedral groups in addition to rotations. PMID:10927430

  10. Reliable Real-Time Solution of Parametrized Partial Differential Equations: Reduced-Basis Output Bound Methods. Appendix 2

    NASA Technical Reports Server (NTRS)

    Prudhomme, C.; Rovas, D. V.; Veroy, K.; Machiels, L.; Maday, Y.; Patera, A. T.; Turinici, G.; Zang, Thomas A., Jr. (Technical Monitor)

    2002-01-01

    We present a technique for the rapid and reliable prediction of linear-functional outputs of elliptic (and parabolic) partial differential equations with affine parameter dependence. The essential components are (i) (provably) rapidly convergent global reduced basis approximations, Galerkin projection onto a space W(sub N) spanned by solutions of the governing partial differential equation at N selected points in parameter space; (ii) a posteriori error estimation, relaxations of the error-residual equation that provide inexpensive yet sharp and rigorous bounds for the error in the outputs of interest; and (iii) off-line/on-line computational procedures, methods which decouple the generation and projection stages of the approximation process. The operation count for the on-line stage, in which, given a new parameter value, we calculate the output of interest and associated error bound, depends only on N (typically very small) and the parametric complexity of the problem; the method is thus ideally suited for the repeated and rapid evaluations required in the context of parameter estimation, design, optimization, and real-time control.

  11. Superstructures and multijunction cells for high efficiency energy conversion

    NASA Technical Reports Server (NTRS)

    Wagner, M.; Leburton, J. P.

    1985-01-01

    Potential applications of superlattices to photovoltaic structures are discussed. A single-bandgap, multijunction cell with selective electrodes for lateral transport of collected carriers is proposed. The concept is based on similar doping superlattice (NIPI) structures. Computer simulations show that by reducing bulk recombination losses, the spectral response of such cells is enhanced, particularly for poor quality materials with short diffusion lengths. Dark current contributions of additional junctions result in a trade-off between short-circuit current and open-circuit voltage as the number of layers is increased. One or two extra junctions appear to be optimal.

  12. Pulse Dipolar ESR and Protein Superstructures and Function

    NASA Astrophysics Data System (ADS)

    Freed, Jack

    2014-03-01

    Pulse dipolar electron-spin resonance (PDS-ESR) has emerged as a powerful methodology for the study of protein structure and function. This technology, in the form of double quantum coherence (DQC) - ESR and double-electron-electron resonance (DEER) in conjunction with site-directed spin-labeling will be described. It enables the measurement of distances and their distributions in the range of 1-9 nm between pairs of spins labeled at two sites in the protein. Many biological objects can be studied: soluble and membrane proteins, protein complexes, etc. Many sample morphologies are possible: uniform, heterogeneous, etc. thereby permitting a variety of sample types: solutions, liposomes, micelles, bicelles. Concentrations from micromolar to tens of millimolar are amenable, requiring only small amounts of biomolecules. The distances are quite accurate, so a relatively small number of them are sufficient to reveal structures and functional details. Several examples will be shown. The first is defining the protein complexes that mediate bacterial chemotaxis, which is the process whereby cells modulate their flagella-driven motility in response to environmental cues. It relies on a complex sensory apparatus composed of transmembrane receptors, histidine kinases, and coupling proteins. PDS-based models have captured key architectural features of the receptor kinase arrays and the flagellar motor, and their changes in conformation and dynamics that accompany kinase activation and motor switching. Another example will be determining the conformational states and cycling of a membrane transporter, GltPh, which is a homotrimer, in its apo, substrate-bound, and inhibitor-bound, states in membrane vesicles providing insight into its energetics. In a third example the structureless (in solution) proteins alpha-synuclein and tau, which are important in Parkinson's disease and in neurodegeneration will be described and the structures they take on in contact with membranes will be

  13. A spray-drying strategy for synthesis of nanoscale metal-organic frameworks and their assembly into hollow superstructures

    NASA Astrophysics Data System (ADS)

    Carné-Sánchez, Arnau; Imaz, Inhar; Cano-Sarabia, Mary; Maspoch, Daniel

    2013-03-01

    Metal-organic frameworks (MOFs) are among the most attractive porous materials known today. Their miniaturization to the nanoscale—into nanoMOFs—is expected to serve myriad applications from drug delivery to membranes, to open up novel avenues to more traditional storage and catalysis applications, and to enable the creation of sophisticated superstructures. Here, we report the use of spray-drying as a versatile methodology to assemble nanoMOFs, yielding spherical hollow superstructures with diameters smaller than 5 µm. This strategy conceptually mimics the emulsions used by chemists to confine the synthesis of materials, but does not require secondary immiscible solvents or surfactants. We demonstrate that the resulting spherical, hollow superstructures can be processed into stable colloids, whose disassembly by sonication affords discrete, homogeneous nanoMOFs. This spray-drying strategy enables the construction of multicomponent MOF superstructures, and the encapsulation of guest species within these superstructures. We anticipate that this will provide new routes to capsules, reactors and composite materials.

  14. Taurolidine-citrate lock solution (TauroLock) significantly reduces CVAD-associated grampositive infections in pediatric cancer patients

    PubMed Central

    Simon, Arne; Ammann, Roland A; Wiszniewsky, Gertrud; Bode, Udo; Fleischhack, Gudrun; Besuden, Mette M

    2008-01-01

    Background Taurolidin/Citrate (TauroLock™), a lock solution with broad spectrum antimicrobial activity, may prevent bloodstream infection (BSI) due to coagulase-negative staphylococci (CoNS or 'MRSE' in case of methicillin-resistant isolates) in pediatric cancer patients with a long term central venous access device (CVAD, Port- or/Broviac-/Hickman-catheter type). Methods In a single center prospective 48-months cohort study we compared all patients receiving anticancer chemotherapy from April 2003 to March 2005 (group 1, heparin lock with 200 IU/ml sterile normal saline 0.9%; Canusal® Wockhardt UK Ltd, Wrexham, Wales) and all patients from April 2005 to March 2007 (group 2; taurolidine 1.35%/Sodium Citrate 4%; TauroLock™, Tauropharm, Waldbüttelbrunn, Germany). Results In group 1 (heparin), 90 patients had 98 CVAD in use during the surveillance period. 14 of 30 (47%) BSI were 'primary Gram positive BSI due to CoNS (n = 4) or MRSE (n = 10)' [incidence density (ID); 2.30 per 1000 inpatient CVAD-utilization days]. In group 2 (TauroLock™), 89 patients had 95 CVAD in use during the surveillance period. 3 of 25 (12%) BSI were caused by CoNS. (ID, 0.45). The difference in the ID between the two groups was statistically significant (P = 0.004). Conclusion The use of Taurolidin/Citrate (TauroLock™) significantly reduced the number and incidence density of primary catheter-associated BSI due to CoNS and MRSE in pediatric cancer patients. PMID:18664278

  15. Evaporation- and Solution-Process-Feasible Highly Efficient Thianthrene-9,9',10,10'-Tetraoxide-Based Thermally Activated Delayed Fluorescence Emitters with Reduced Efficiency Roll-Off.

    PubMed

    Xie, Gaozhan; Li, Xianglong; Chen, Dongjun; Wang, Zhiheng; Cai, Xinyi; Chen, Dongcheng; Li, Yunchuan; Liu, Kunkun; Cao, Yong; Su, Shi-Jian

    2016-01-01

    Two novel evaporation- and solution-process-feasible thermally activated delayed fluorescence emitters, green-light-emission ACRDSO2 and yellow-light-emission PXZDSO2, based on a brand-new electron-acceptor moiety thianthrene-9,9',10,10'-tetraoxide, are developed for organic light-emitting diodes. The solution-processed devices, without any hole-transport layer, exhibit competitive performance and reduced efficiency roll-off compared with corresponding vacuum-deposited devices. PMID:26551788

  16. Novel meso-superstructured solar cells with a high efficiency exceeding 12%.

    PubMed

    Hu, Yun Hang

    2014-04-01

    The dye-sensitized solar cell (DSSC) is representative of next generation photovoltaic devices. State-of-the-art DSSCs have been established for two decades. However, the recent application of organic-inorganic hybrid perovskites on nanoparticle Al2 O3 film has totally changed the DSSC structure, leading to a new type of solar cell - meso-superstructured solar cells (MSSCs) with a high power conversion efficiency exceeding 12%. This article summarizes this impressive progress and discusses the challenges of MSSCs. PMID:24448748

  17. Visualizing the photovoltaic behavior of a type-II p-n heterojunction superstructure

    SciTech Connect

    Xing, Juanjuan; Takeguchi, Masaki; Hashimoto, Ayako; Cao, Junyu; Ye, Jinhua

    2014-04-21

    Photovoltaic behavior of a CaFe{sub 2}O{sub 4}/ZnFe{sub 2}O{sub 4} p-n multi-junction was investigated with electron holography combined with an in situ light irradiation system. Potential profiles of the samples with and without light irradiation were extracted to measure the open circuit photovoltage generated either by the whole heterojunction superstructure or from each p-n junction. Investigation on the variation in the energy band configuration under light irradiation revealed the mechanism involved in the photoelectric effect, with respect to the properties of the heterojunction and its periodic quantum structure.

  18. Incommensurate superstructure in heavily doped fullerene layer on Bi/Si(111) surface

    NASA Astrophysics Data System (ADS)

    Gruznev, D. V.; Bondarenko, L. V.; Tupchaya, A. Y.; Matetskiy, A. V.; Zotov, A. V.; Saranin, A. A.

    2015-08-01

    Cs adsorption onto the C60-covered Si(111)-β- √{ 3 } × √{ 3 } -Bi reconstruction has been studied by means of scanning tunneling microscopy and photoelectron spectroscopy. Unexpected increase in apparent size of every second C60 molecule has been detected, hereupon the close packed molecular array almost doubles its periodicity. The change affects only the fullerenes that are in direct contact with the metal-induced reconstruction and takes no place already in the second layer. Photoelectron studies have revealed that this incommensurate "2 × 2" superstructure of a heavily doped C60 monolayer remains in an insulating state regardless of doping level.

  19. Visualizing the photovoltaic behavior of a type-II p-n heterojunction superstructure

    NASA Astrophysics Data System (ADS)

    Xing, Juanjuan; Takeguchi, Masaki; Hashimoto, Ayako; Cao, Junyu; Ye, Jinhua

    2014-04-01

    Photovoltaic behavior of a CaFe2O4/ZnFe2O4 p-n multi-junction was investigated with electron holography combined with an in situ light irradiation system. Potential profiles of the samples with and without light irradiation were extracted to measure the open circuit photovoltage generated either by the whole heterojunction superstructure or from each p-n junction. Investigation on the variation in the energy band configuration under light irradiation revealed the mechanism involved in the photoelectric effect, with respect to the properties of the heterojunction and its periodic quantum structure.

  20. Microfractures in metal-ceramic and all-ceramic implant-supported fixed dental prostheses caused by superstructure fixation.

    PubMed

    Karl, Matthias; Graef, Friedrich; Wichmann, Manfred; Beck, Nina

    2012-01-01

    The effect of ceramic veneering on the passivity of fit of cast metal and CAD/CAM-fabricated zirconia ceramic implant-supported three-unit cement-retained restorations was investigated, as well as the effect of misfit stress on the marginal integrity of ceramic veneers. Superstructures were fabricated using cast metal or by CAD/CAM milling of presintered or HIP zirconia ceramic (n=10). Before and after veneering, strain gages were used to measure in vitro the strain developed in all the restorations as a result of superstructure fixation. Fluorescent penetrant method was used to detect microcracks developed in ceramic veneers. Cast frameworks showed significantly higher strain values than CAD/CAM frameworks (p=0.000). Veneering significantly increased strain development in all CAD/CAM frameworks (p=0.000). Compared to zirconia ceramic restorations, significantly more microcracks were observed in cast restorations (p=0.000) both before and after superstructure fixation. PMID:22673463

  1. A sequence of transformations related to the formation of M{sub 3}X{sub 2}-type superstructures

    SciTech Connect

    Gusev, A. I.

    2015-01-15

    A symmetry analysis of monoclinic, orthorhombic, and trigonal M{sub 3}X{sub 2}-type superstructures that can be formed in strongly stoichiometric MX{sub y} compounds with B1 structure is carried out. Channels of order-disorder transitions MX{sub y} → M{sub 3}X{sub 2} are determined. It is shown that, as temperature decreases, two physically admissible sequences of transformations associated with the formation of M{sub 3}X{sub 2} superstructures are possible in nonstoichiometric MX{sub y} compounds of group IV transition metals. By an example of vanadium carbide VC{sub y}, it is demonstrated that orthorhombic or monoclinic V{sub 3}C{sub 2} superstructures can be obtained with the formation of a nanostructure.

  2. Synthesis of micro-sized shell-isolated 3D plasmonic superstructures for in situ single-particle SERS monitoring

    NASA Astrophysics Data System (ADS)

    Zhang, Kun; Zhao, Jingjing; Ji, Ji; Liu, Baohong

    2016-04-01

    A single-particle SERS system enabling real-time and in situ observation of Au-catalyzed reactions has been developed. Both the catalytic activity and the SERS effect are coupled into a single bi-functional 3D superstructure comprising Au nanosatellites self-assembled onto a shell-insulated Ag microflower core, which eliminates the interference from photocatalysis.A single-particle SERS system enabling real-time and in situ observation of Au-catalyzed reactions has been developed. Both the catalytic activity and the SERS effect are coupled into a single bi-functional 3D superstructure comprising Au nanosatellites self-assembled onto a shell-insulated Ag microflower core, which eliminates the interference from photocatalysis. Electronic supplementary information (ESI) available: Details of the synthesis and characterization of the Ag@SiO2@Au superstructures (SEM and TEM images, UV/vis and SERS spectra). See DOI: 10.1039/c6nr00278a

  3. Three-dimensional surface-enhanced Raman scattering hotspots in spherical colloidal superstructure for identification and detection of drugs in human urine.

    PubMed

    Han, Zhenzhen; Liu, Honglin; Wang, Bin; Weng, Shizhuang; Yang, Liangbao; Liu, Jinhuai

    2015-01-01

    Rapid component separation and robust surface-enhanced Raman scattering (SERS) identification of drugs in real human urine remain an attractive challenge because of the sample complexity, low molecular affinity for metal surface, and inefficient use of hotspots in one- or two-dimensional (2D) geometries. Here, we developed a 5 min strategy of cyclohexane (CYH) extraction for separating amphetamines from human urine. Simultaneously, an oil-in-water emulsion method is used to assemble monodisperse Ag nanoparticles in the CYH phase into spherical colloidal superstructures in the aqueous phase. These superstructures create three-dimensional (3D) SERS hotspots which exist between every two adjacent particles in 3D space, break the traditional 2D limitation, and extend the hotspots into the third dimension along the z-axis. In this platform, a conservative estimate of Raman enhancement factor is larger than 10(7), and the same CYH extraction processing results in a high acceptability and enrichment of drug molecules in 3D hotspots which demonstrates excellent stability and reproducibility and is suitable for the quantitative examination of amphetamines in both aqueous and organic phases. Parallel ultraperformance liquid chromatography (UPLC) examinations corroborate an excellent performance of our SERS platform for the quantitative analysis of methamphetamine (MA) in both aqueous solution and real human urine, of which the detection limits reach 1 and 10 ppb, respectively, with tolerable signal-to-noise ratios. Moreover, SERS examinations on different proportions of MA and 3,4-methylenedioxymethamphetamine (MDMA) in human urine demonstrate an excellent capability of multiplex quantification of ultratrace analytes. By virtue of a spectral classification algorithm, we realize the rapid and accurate recognition of weak Raman signals of amphetamines at trace levels and also clearly distinguish various proportions of multiplex components. Our platform for detecting drugs

  4. Superstructures formed by orientationally ordered tetrahedra in the bcc lattice: new diffusionless order-disorder transition in solids

    NASA Astrophysics Data System (ADS)

    Tamura, Ryuji

    2015-03-01

    We investigated and clarified the superstructures formed by tetrahedra in the bcc lattice within the framework of second-order transitions. Compliance with both the Landau and Lifshitz conditions was investigated for all possible superstructures and, based on this, we demonstrate that bcc crystals that contain tetrahedra at an inversion center can exhibit a variety of second-order transitions, which are regarded as a new type of diffusionless order-disorder transition with antiferroic orientational orders. Finally, we show that the transition gives rise to a new glassy state. Breaking of the local inversion symmetry may lead to a new orientational glass, which is reminiscent of spin glasses in magnetism.

  5. The influence of tightening sequence and method on screw preload in implant superstructures.

    PubMed

    Al-Sahan, Maha M; Al Maflehi, Nassr S; Akeel, Riyadh F

    2014-01-01

    This study evaluated the effect of six screw-tightening sequences and two tightening methods on the screw preload in implant-supported superstructures. The preload was measured using strain gauges following the screw tightening of a metal framework connected to four implants. The experiment included six sequences ([1] 1-2-3-4, [2] 4-2-3-1, [3] 4-3-1-2, [4] 1-4-2-3, [5] 2-3-4-1, and [6] 3-2-4-1), two methods (onestep, three-step), and five replications. Significant differences were found between tightening sequences and methods. In the three-step method, a higher total preload was found in sequences 2 (312 ± 85 N), 3 (246 ± 54 N), and 4 (310 ± 96 N). In the one-step method, a higher total preload was found in sequences 1 (286 ± 94 N), 5 (764 ± 142 N), and 6 (350 ± 69 N). It is concluded that the highest total screw preload was achieved when anterior implants of the superstructure were first tightened in one step, followed by posterior implants. PMID:24392482

  6. Morphology-Dependent Electrochemical Properties of CuS Hierarchical Superstructures.

    PubMed

    Hosseinpour, Zahra; Scarpellini, Alice; Najafishirtari, Sharif; Marras, Sergio; Colombo, Massimo; Alemi, Abdolali; De Volder, Michaël; George, Chandramohan; Lesnyak, Vladimir

    2015-11-16

    Hierarchical superstructures formed by self-assembled nanoparticles exhibit interesting electrochemical properties that can potentially be exploited in Li-ion batteries (LIBs) as possible electrode materials. In this work, we tested two different morphologies of CuS superstructures for electrodes, namely, tubular dandelion-like and ball-like assemblies, both of which are composed of similar small covellite nanoparticles. These two CuS morphologies are characterized by their markedly different electrochemical performances, suggesting that their complex structures/morphologies influence the electrochemical properties. At 1.12 A g(-1), the cells made with CuS tubular structures delivered about 420 mAh g(-1), and at 0.56 A g(-1), the capacity was as high as about 500 mAh g(-1) with good capacity retention. Their ease of preparation and processing, together with good electrochemical performance, make CuS tubular dandelion-like clusters attractive for developing low-cost LIBs based on conversion reactions. PMID:26312569

  7. The Effect of Superstructures Connected to Implants with Different Surface Properties on the Surrounding Bone

    PubMed Central

    Koretake, Katsunori; Oue, Hiroshi; Okada, Shinsuke; Takeda, Yosuke; Doi, Kazuya; Akagawa, Yasumasa; Tsuga, Kazuhiro

    2015-01-01

    The objective of this study was to investigate how the connection of superstructures to implants with different surface properties affects the surrounding bone. The right and left mandibular premolars and molars of 5 dogs were extracted. After 12 weeks, a machined implant was placed mesially and an anodized implant was placed distally on one side of the edentulous jaw, with the positions reversed on the opposite side. Twelve weeks after implantation, splinted superstructures were set to the implants. At 24 weeks after implantation, the implant stability quotient (ISQ) was measured, radiographs were obtained. Removal torque values were measured and histologic observation was performed. The ISQ values at 24 weeks after implantation were not significantly different between the groups. The removal torque values were significantly different between the distal anodized and distal machined implants (p < 0.05). From 12 to 24 weeks, marginal bone losses were not significantly different between the groups. Fluorescent observation of tissue samples revealed bone-remodeling activity around all of the implants. The results of this study suggest that when implants with different surface properties are connected, machined implants at the most distal sites might be a potential risk factor for implant-bone binding. PMID:26213978

  8. Split-dose vs same-day reduced-volume polyethylene glycol electrolyte lavage solution for morning colonoscopy

    PubMed Central

    Chan, Wah-Kheong; Azmi, Najib; Mahadeva, Sanjiv; Goh, Khean-Lee

    2014-01-01

    AIM: To compare same-day whole-dose vs split-dose of 2-litre polyethylene glycol electrolyte lavage solution (PEG-ELS) plus bisacodyl for colon cleansing for morning colonoscopy. METHODS: Consecutive adult patients undergoing morning colonoscopy were allocated into two groups i.e., same-day whole-dose or split-dose of 2-litre PEG-ELS. Investigators and endoscopists were blinded to the allocation. All patients completed a questionnaire that was designed by Aronchick and colleagues to assess the tolerability of the bowel preparation regime used. In addition, patients answered an ordinal five-value Likert scale question on comfort level during bowel preparation. Endoscopists graded the quality of bowel preparation using the Boston bowel preparation scale (BBPS). In addition, endoscopists gave an overall grading of the quality of bowel preparation. Cecal intubation time, withdrawal time, total colonoscopy time, adenoma detection rate and number of adenomas detected for each patient were recorded. Sample size was calculated using an online calculator for binary outcome non-inferiority trial. Analyses was based upon intent-to-treat. Significance was assumed at P-value < 0.05. RESULTS: Data for 295 patients were analysed. Mean age was 62.0 ± 14.4 years old and consisted of 50.2 % male. There were 143 and 152 patients in the split-dose and whole-dose group, respectively. Split-dose was as good as whole-dose for quality of bowel preparation. The total BBPS score was as good in the split-dose group compared to the whole-dose group [6 (6-8) vs 6 (6-7), P = 0.038]. There was no difference in cecal intubation rate, cecal intubation time, withdrawal time, total colonoscopy time and adenoma detection rate. Median number of adenoma detected was marginally higher in the split-dose group [2 (1-3) vs 1 (1-2), P = 0.010]. Patients in the whole-dose group had more nausea (37.5% vs 25.2%, P = 0.023) and vomiting (16.4% vs 8.4%, P = 0.037), and were less likely to complete the bowel

  9. Resistant starch alters gut microbiota and reduces uremic retention solutes in rats with adenine-induced chronic kidney disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chronic kidney disease (CKD) is characterized by the reduced ability to void urine, leading to accumulation of waste products in the body. Recently, it has been observed that patients with CKD have an altered gut microbiome. This may in part be due to reduced fiber intake. Patients with CKD are ofte...

  10. Immersion in antimicrobial solutions reduces Salmonella enterica and Shiga toxin-producing Escherichia coli on beef cheek meat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to determine the effect of immersing beef cheek meat in antimicrobial solutions on the reduction of O157:H7 Shiga toxin–producing Escherichia coli (STEC), non-O157:H7 STEC, and Salmonella enterica. Beef cheek meat was inoculated with O157:H7 STEC, non-O157:H7 STEC, an...

  11. Photoreversible micellar solution as a smart drag-reducing fluid for use in district heating/cooling systems.

    PubMed

    Shi, Haifeng; Ge, Wu; Oh, Hyuntaek; Pattison, Sean M; Huggins, Jacob T; Talmon, Yeshayahu; Hart, David J; Raghavan, Srinivasa R; Zakin, Jacques L

    2013-01-01

    A photoresponsive micellar solution is developed as a promising working fluid for district heating/cooling systems (DHCs). It can be reversibly switched between a drag reduction (DR) mode and an efficient heat transfer (EHT) mode by light irradiation. The DR mode is advantageous during fluid transport, and the EHT mode is favored when the fluid passes through heat exchangers. This smart fluid is an aqueous solution of cationic surfactant oleyl bis(2-hydroxyethyl)methyl ammonium chloride (OHAC, 3.4 mM) and the sodium salt of 4-phenylazo benzoic acid (ACA, 2 mM). Initially, ACA is in a trans configuration and the OHAC/ACA solution is viscoelastic and exhibits DR (of up to 80% relative to pure water). At the same time, this solution is not effective for heat transfer. Upon UV irradiation, trans-ACA is converted to cis-ACA, and in turn, the solution is converted to its EHT mode (i.e., it loses its viscoelasticity and DR) but it now has a heat-transfer capability comparable to that of water. Subsequent irradiation with visible light reverts the fluid to its viscoelastic DR mode. The above property changes are connected to photoinduced changes in the nanostructure of the fluid. In the DR mode, the OHAC/trans-ACA molecules assemble into long threadlike micelles that impart viscoelasticity and DR capability to the fluid. Conversely, in the EHT mode the mixture of OHAC and cis-ACA forms much shorter cylindrical micelles that contribute to negligible viscoelasticity and effective heat transfer. These nanostructural changes are confirmed by cryo-transmission electron microscopy (cryo-TEM), and the photoisomerization of trans-ACA and cis-ACA is verified by (1)H NMR. PMID:23210742

  12. Bioinspired Synthesis of CaCO3 Superstructures through a Novel Hydrogel Composite Membranes Mineralization Platform: A Comprehensive View.

    PubMed

    Di Profio, Gianluca; Salehi, Shabnam Majidi; Caliandro, Rocco; Guccione, Pietro; Nico, Giovanni; Curcio, Efrem; Fontananova, Enrica

    2016-01-27

    Hydrogel composite membranes (HCMs) are used as novel mineralization platforms for the bioinspired synthesis of CaCO3 superstructures. A comprehensive statistical analysis of the experimental results reveals quantitative relationships between crystallization conditions and crystal texture and a strong selectivity toward complex morphologies when monomers bearing carboxyl and hydroxyl groups are used together in the hydrogel layer synthesis in HCMs. PMID:26609641

  13. First-principles identifications of superstructures of germanene on Ag(111) surface and h-BN substrate.

    PubMed

    Li, Linyang; Zhao, Mingwen

    2013-10-21

    Using first-principle calculations, we show that germanene can attach on Ag(111) surface forming germanene/Ag superstructures via electrostatic interactions. In all the optimized superstructures, we found a kind of epitaxially grown germanene is similar to the isolated low-buckled germanene. The adsorption energy of germanene on Ag(111) surface is about -464 meV to -428 meV per Ge atom, close to that of silicene on Ag(111) surface. Germanene on Ag(111) is a continuous layer and the p-d hybridization between Ag and Ge is revealed. These indicate Ag(111) surface is a good substrate for stabilizing germanene. The band structures of germanene are submerged in electronic states of metallic Ag substrate. To preserve the excellent electronic structures of germanene, we also considered another substrate hexagonal boron nitride (h-BN). We show that germanene can stably attach on h-BN substrate via Van der Waals (vdW) interactions, forming germanene/BN Moiré superstructures. At equilibrium state, a small band gap of about 50 meV is opened up in the Dirac point of germanene, whose value is insensitive to the rotation angle and the sliding between the two lattices, but can be effectively tuned by changing the interlayer distance. In these superstructures, the high carrier mobility of germanene is well preserved. These imply that h-BN can act as an ideal substrate material for germanene to achieve specific applications in nanoscale electronic devices. PMID:23995323

  14. Ab initio studies of the formation of a Y1-xNi2 superstructure with ordered Y vacancies

    NASA Astrophysics Data System (ADS)

    Lindbaum, A.; Hafner, J.; Gratz, E.

    1999-02-01

    Ab initio total-energy calculations have been performed to study the structural stability of Y1-xNi2. In the literature (Villars P and Calvert L D 1985 Pearson's Handbook of Crystallographic Data for Intermetallic Phases (Materials Park, OH: American Society for Metals)) YNi2 is often considered to show the cubic Laves phase structure, but x-ray diffraction experiments of Latroche et al ( J. Less-Common Met. 161 L27) showed that YNi2 crystallizes in a superstructure of C15 with ordered Y vacancies with a stoichiometry of approximately Y0.95Ni2. The total-energy calculations for the superstructure and for the ideal C15 structure, as well as for the neighbouring phases in the Y-Ni phase diagram YNi and YNi3, confirm that the formation of the superstructure with Y vacancies is favoured against the formation of the pure C15 compound YNi2. The calculated relaxation of the atoms around the vacancies is also in good agreement with the experimental results (Latroche et al), demonstrating that the relaxation of strains in the Y sublattice is the driving mechanism for formation of vacancies. In addition, the electronic properties of the vacancy superstructure have been examined.

  15. A Critical Reassessment of Marxian Base-Superstructure Explanations of the Role of Education in Social Change.

    ERIC Educational Resources Information Center

    Chun, Kyung-Kap

    1986-01-01

    Examines how four major versions of neo-Marxism (i.e., Hegelian, Phenomenological, Structuralist Marxism, and the Frankfurt School) attempt to overcome the base-superstructure thesis of the political economists of education. Considers the implicit social ontological and epistemological assumptions and the related theory of education of each.…

  16. Synthesis of micro-sized shell-isolated 3D plasmonic superstructures for in situ single-particle SERS monitoring.

    PubMed

    Zhang, Kun; Zhao, Jingjing; Ji, Ji; Liu, Baohong

    2016-04-21

    A single-particle SERS system enabling real-time and in situ observation of Au-catalyzed reactions has been developed. Both the catalytic activity and the SERS effect are coupled into a single bi-functional 3D superstructure comprising Au nanosatellites self-assembled onto a shell-insulated Ag microflower core, which eliminates the interference from photocatalysis. PMID:27044886

  17. Study on superstructure in ion co-doped BiFeO3 by using transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Pu, Shi-Zhou; Guo, Chao; Li, Mei-Ya; Chen, Zhen-Lian; Zou, Hua-Min

    2015-04-01

    La3+ and V5+ co-doped BiFeO3 ceramics are synthesized by rapid liquid sintering technique. The modulated structure in Bi0.85La0.15Fe0.97V0.03O3 is investigated by using transmission electron microscopy (TEM). Two kinds of superstructures are observed in the samples. One is the component modulated superstructure and twin-domain, which is generated by La3+ ordered substitution for Bi3+ and frequently appears. The chemical composition of the superstructure is explored by x-ray energy dispersive spectroscopy (EDS). The model of the ordered structure is proposed. Simulation based on the model is conducted. The second is the fluorite-type δ-Bi2O3 related superstructure. The relation between the ferroelectric property and the microstructure of the sample is also discussed. Project supported by the National Natural Science Foundation of China (Grant Nos. 51372174, 11074193, and 51132001) and the Fundamental Research Funds for the Central Universities.

  18. Small-Angle X-ray Study of the Three-Dimensional Collagen/Mineral Superstructure in Intramuscular Fish Bone

    SciTech Connect

    Zhou,H.; Burger, C.; Sics, I.; Hsiao, B.; Chu, B.; Graham, L.; Glimcher, M.

    2007-01-01

    Synchrotron small-angle X-ray scattering (SAXS) was conducted on native intramuscular shad/herring bone samples. Two-dimensional SAXS patterns were quantitatively analyzed with special consideration for preferred orientation effects, leading to new insights into the three-dimensional superstructure of mineralized collagen fibrils in shad/herring bone.

  19. Novel superstructure of the rocksalt type and element distribution in germanium tin antimony tellurides

    SciTech Connect

    Rosenthal, Tobias; Welzmiller, Simon; Neudert, Lukas; Urban, Philipp; Fitch, Andy; Oeckler, Oliver

    2014-11-15

    A superstructure of the rocksalt-type observed in quenched CVT-grown single crystals of Ge{sub 3.25(7)}Sn{sub 1.10(3)}Sb{sub 1.10(3)}Te{sub 6} was elucidated by X-ray diffraction using fourfold twinned crystals (space group P3{sup ¯}m1, a=4.280(1) Å, c=20.966(3) Å). The structure is built up of distorted rocksalt-type building blocks typical for long-range ordered GST materials and substitution variants thereof. In contrast to those phases, an exclusive ABC-type cubic stacking sequence of the Te-atom layers is present. High-resolution electron microscopy reveals spheroidal domains with this structure (average diameter 25 nm) whose stacking direction is perpendicular to the 〈1 1 1〉 directions of the basic rocksalt-type structure. Additional slab-like domains with a lateral extension up to 1 µm occasionally result in a hierarchical structure motif. Due to the similar electron counts of the elements involved, resonant diffraction was used in order to elucidate the element distribution in rocksalt-type building blocks of the stable layered compound 39R-Ge{sub 3}SnSb{sub 2}Te{sub 7} (R3{sup ¯}m, a=4.24990(4) Å, c=73.4677(9) Å). Sb tends to occupy the atom site close to the van der Waals gaps while Ge concentrates in the center of the building blocks. - Graphical abstract: High-resolution transmission electron micrograph, SAED pattern and reciprocal lattice section of X-ray single crystal data of Ge{sub 3.25}Sn{sub 1.1}Sb{sub 1.1}Te{sub 6} with an 11P-type superstructure of the rocksalt type. - Highlights: • A novel superstructure of the rocksalt-type in the system Ge–Sn–Sb–Te is elucidated. • It combines the cubic stacking of the HT phase with building blocks of the RT phase. • It indicates the ordering mechanism during the phase transition of GST materials. • A hierarchical structure motif is promising with respect to the reduction of κ{sub L}. • Resonant diffraction reveals the element distribution in 39R-Ge{sub 3}SnSb{sub 2}Te{sub 7}.

  20. Nanoscale superstructures assembled by polymerase chain reaction (PCR): programmable construction, structural diversity, and emerging applications.

    PubMed

    Kuang, Hua; Ma, Wei; Xu, Liguang; Wang, Libing; Xu, Chuanlai

    2013-11-19

    Polymerase chain reaction (PCR) is an essential tool in biotechnology laboratories and is becoming increasingly important in other areas of research. Extensive data obtained over the last 12 years has shown that the combination of PCR with nanoscale dispersions can resolve issues in the preparation DNA-based materials that include both inorganic and organic nanoscale components. Unlike conventional DNA hybridization and antibody-antigen complexes, PCR provides a new, effective assembly platform that both increases the yield of DNA-based nanomaterials and allows researchers to program and control assembly with predesigned parameters including those assisted and automated by computers. As a result, this method allows researchers to optimize to the combinatorial selection of the DNA strands for their nanoparticle conjugates. We have developed a PCR approach for producing various nanoscale assemblies including organic motifs such as small molecules, macromolecules, and inorganic building blocks, such as nanorods (NRs), metal, semiconductor, and magnetic nanoparticles (NPs). We start with a nanoscale primer and then modify that building block using the automated steps of PCR-based assembly including initialization, denaturation, annealing, extension, final elongation, and final hold. The intermediate steps of denaturation, annealing, and extension are cyclic, and we use computer control so that the assembled superstructures reach their predetermined complexity. The structures assembled using a small number of PCR cycles show a lower polydispersity than similar discrete structures obtained by direct hybridization between the nanoscale building blocks. Using different building blocks, we assembled the following structural motifs by PCR: (1) discrete nanostructures (NP dimers, NP multimers including trimers, pyramids, tetramers or hexamers, etc.), (2) branched NP superstructures and heterochains, (3) NP satellite-like superstructures, (4) Y-shaped nanostructures and DNA

  1. Evaluation of Linear, Inviscid, Viscous, and Reduced-Order Modeling Aeroelastic Solutions of the AGARD 445.6 Wing Using Root Locus Analysis

    NASA Technical Reports Server (NTRS)

    Silva, Walter A.; Perry, Boyd III; Chwalowski, Pawel

    2014-01-01

    Reduced-order modeling (ROM) methods are applied to the CFD-based aeroelastic analysis of the AGARD 445.6 wing in order to gain insight regarding well-known discrepancies between the aeroelastic analyses and the experimental results. The results presented include aeroelastic solutions using the inviscid CAP-TSD code and the FUN3D code (Euler and Navier-Stokes). Full CFD aeroelastic solutions and ROM aeroelastic solutions, computed at several Mach numbers, are presented in the form of root locus plots in order to better reveal the aeroelastic root migrations with increasing dynamic pressure. Important conclusions are drawn from these results including the ability of the linear CAP-TSD code to accurately predict the entire experimental flutter boundary (repeat of analyses performed in the 1980's), that the Euler solutions at supersonic conditions indicate that the third mode is always unstable, and that the FUN3D Navier-Stokes solutions stabilize the unstable third mode seen in the Euler solutions.

  2. Morphology-controlled hydrothermal synthesis of MnCO{sub 3} hierarchical superstructures with Schiff base as stabilizer

    SciTech Connect

    Hu, He; Xu, Jie-yan; Yang, Hong; Liang, Jie; Yang, Shiping; Wu, Huixia

    2011-11-15

    Graphical abstract: MnCO3 microcrystals with hierarchical superstructures were synthesized by using the CO2 in atmosphere as carbonate ions source and Schiff base as shape guiding-agent in water/ethanol system under hydrothermal condition. Highlights: {yields} The most interesting in this work is the use of the greenhouse gases CO{sub 2} in atmosphere as carbonate ions source to precipitate with Mn{sup 2+} for producing MnCO{sub 3} crystals. {yields} This work is the first report related to the small organic molecule Schiff base as shape guiding-agent to produce different MnCO{sub 3} hierarchical superstructures. {yields} We are controllable synthesis of the MnCO{sub 3} hierarchical superstructures such as chrysanthemum, straw-bundle, dumbbell and sphere-like microcrystals. {yields} The as-prepared MnCO{sub 3} could be used precursor to fabricate the Mn{sub 2}O{sub 3} hierarchical superstructures after thermal decomposition at high temperature. -- Abstract: MnCO{sub 3} with hierarchical superstructures such as chrysanthemum, straw-bundle, dumbbell and sphere-like were synthesized in water/ethanol system under environment-friendly hydrothermal condition. In the synthesis process, the CO{sub 2} in atmosphere was used as the source of carbonate ions and Schiff base was used as shape guiding-agent. The different superstructures of MnCO{sub 3} could be obtained by controlling the hydrothermal temperature, the molar ratio of manganous ions to the Schiff base, or the volume ratio of water to ethanol. A tentative growth mechanism for the generation of MnCO{sub 3} superstructures was proposed based on the rod-dumbbell-sphere model. Furthermore, the MnCO{sub 3} as precursor could be further successfully transferred to Mn{sub 2}O{sub 3} microstructure after heating in the atmosphere at 500 {sup o}C, and the morphology of the Mn{sub 2}O{sub 3} was directly determined by that of the MnCO{sub 3} precursor.

  3. Using a two-step matrix solution to reduce the run time in KULL's magnetic diffusion package

    SciTech Connect

    Brunner, T A; Kolev, T V

    2010-12-17

    Recently a Resistive Magnetohydrodynamics (MHD) package has been added to the KULL code. In order to be compatible with the underlying hydrodynamics algorithm, a new sub-zonal magnetics discretization was developed that supports arbitrary polygonal and polyhedral zones. This flexibility comes at the cost of many more unknowns per zone - approximately ten times more for a hexahedral mesh. We can eliminate some (or all, depending on the dimensionality) of the extra unknowns from the global matrix during assembly by using a Schur complement approach. This trades expensive global work for cache-friendly local work, while still allowing solution for the full system. Significant improvements in the solution time are observed for several test problems.

  4. Improving microalgal growth with reduced diameters of aeration bubbles and enhanced mass transfer of solution in an oscillating flow field.

    PubMed

    Yang, Zongbo; Cheng, Jun; Lin, Richen; Zhou, Junhu; Cen, Kefa

    2016-07-01

    A novel oscillating gas aerator combined with an oscillating baffle was proposed to generate smaller aeration bubbles and enhance solution mass transfer, which can improve microalgal growth in a raceway pond. A high-speed photography system (HSP) was used to measure bubble diameter and generation time, and online precise dissolved oxygen probes and pH probes were used to measure mass-transfer coefficient and mixing time. Bubble diameter and generation time decreased with decreased aeration gas rate, decreased orifice diameter, and increased water velocity in the oscillating gas aerator. The optimized oscillating gas aerator decreased bubble diameter and generation time by 25% and 58%, respectively, compared with a horizontal tubular gas aerator. Using an oscillating gas aerator and an oscillating baffle in a raceway pond increased the solution mass-transfer coefficient by 15% and decreased mixing time by 32%; consequently, microalgal biomass yield increased by 19%. PMID:27035474

  5. Effect of reduced winter precipitation and increased temperature on watershed solute flux, 1988-2002, Northern Michigan

    USGS Publications Warehouse

    Stottlemyer, R.; Toczydlowski, D.

    2006-01-01

    Since 1987 we have studied weekly change in winter (December-April) precipitation, snowpack, snowmelt, soil water, and stream water solute flux in a small (176-ha) Northern Michigan watershed vegetated by 65-85 year-old northern hardwoods. Our primary study objective was to quantify the effect of change in winter temperature and precipitation on watershed hydrology and solute flux. During the study winter runoff was correlated with precipitation, and forest soils beneath the snowpack remained unfrozen. Winter air temperature and soil temperature beneath the snowpack increased while precipitation and snowmelt declined. Atmospheric inputs declined for H+, NO 3- , NH 4+ , dissolved inorganic nitrogen (DIN), and SO 42- . Replicated plot-level results, which could not be directly extrapolated to the watershed scale, showed 90% of atmospheric DIN input was retained in surface shallow (<15 cm deep) soils while SO 42- flux increased 70% and dissolved organic carbon (DOC) 30-fold. Most stream water base cation (C B), HCO 3- , and Cl- concentrations declined with increased stream water discharge, K+, NO 3- , and SO 42- remained unchanged, and DOC and dissolved organic nitrogen (DON) increased. Winter stream water solute outputs declined or were unchanged with time except for NO 3- and DOC which increased. DOC and DIN outputs were correlated with the percentage of winter runoff and stream discharge that occurred when subsurface flow at the plot-level was shallow (<25 cm beneath Oi). Study results suggest that the percentage of annual runoff occurring as shallow lateral subsurface flow may be a major factor regulating solute outputs and concentrations in snowmelt-dominated ecosystems. ?? Springer 2006.

  6. Suppression of Grain Boundaries in Graphene Growth on Superstructured Mn-Cu(111) Surface

    NASA Astrophysics Data System (ADS)

    Chen, Wei; Chen, Hua; Lan, Haiping; Cui, Ping; Schulze, Tim P.; Zhu, Wenguang; Zhang, Zhenyu

    2012-12-01

    As undesirable defects, grain boundaries (GBs) are widespread in epitaxial graphene using existing growth methods on metal substrates. Employing density functional theory calculations, we first identify that the misorientations of carbon islands nucleated on a Cu(111) surface lead to the formation of GBs as the islands coalesce. We then propose a two-step kinetic pathway to effectively suppress the formation of GBs. In the first step, large aromatic hydrocarbon molecules are deposited onto a 3×3 superstructured Cu-Mn alloyed surface to seed the initial carbon clusters of a single orientation; in the second step, the seeded islands are enlarged through normal chemical vapor deposition of methane to form a complete graphene sheet. The present approach promises to overcome a standing obstacle in large scale single-crystal graphene fabrication.

  7. High-level organization of isochores into gigantic superstructures in the human genome

    NASA Astrophysics Data System (ADS)

    Carpena, P.; Oliver, J. L.; Hackenberg, M.; Coronado, A. V.; Barturen, G.; Bernaola-Galván, P.

    2011-03-01

    Human DNA shows a complex structure with compositional features at many scales; the isochores—long DNA segments (~105 bp) of relatively homogeneous guanine-cytosine (G + C) content—are the largest well-documented and well-analyzed compositional structures. However, we report here on the existence of a high-level compositional organization of isochores in the human genome. By using a segmentation algorithm incorporating the long-range correlations existing in human DNA, we find that every chromosome is composed of a few huge segments (~ 107 bp) of relatively homogeneous G + C content, which become the largest compositional organization of the genome. Finally, we show evidence of the biological relevance of these superstructures, pointing to a large-scale functional organization of the human genome.

  8. Lack of support for adaptive superstructure NiPt7 : Experiment and first-principles calculations

    NASA Astrophysics Data System (ADS)

    Schönfeld, B.; Engelke, M.; Ruban, A. V.

    2009-02-01

    Order and effective interaction parameters on the Pt-rich side of solid Ni-Pt alloys have been investigated by experimental and first-principles theoretical techniques. Diffuse x-ray scattering was taken from single-crystalline Ni-87.8at.%Pt aged at 603 K to set up a state of thermal equilibrium. From the separated short-range order scattering, effective pair interaction parameters were determined. These experimentally deduced values do not produce the suggested NiPt7 superstructure at lower temperatures. Instead of that, phase separation into NiPt3 regions with L12 structure and a Pt-rich matrix is observed in Monte Carlo simulations and supported by x-ray scattering of Ni-75.2at.%Pt . First-principles calculations at 0 K also show that the suggested NiPt7 phase is unstable against decomposition into NiPt3 and Pt.

  9. Atomistic origin of an ordered superstructure induced superconductivity in layered chalcogenides

    NASA Astrophysics Data System (ADS)

    Ang, R.; Wang, Z. C.; Chen, C. L.; Tang, J.; Liu, N.; Liu, Y.; Lu, W. J.; Sun, Y. P.; Mori, T.; Ikuhara, Y.

    2015-01-01

    Interplay among various collective electronic states such as charge density wave and superconductivity is of tremendous significance in low-dimensional electron systems. However, the atomistic and physical nature of the electronic structures underlying the interplay of exotic states, which is critical to clarifying its effect on remarkable properties of the electron systems, remains elusive, limiting our understanding of the superconducting mechanism. Here, we show evidence that an ordering of selenium and sulphur atoms surrounding tantalum within star-of-David clusters can boost superconductivity in a layered chalcogenide 1T-TaS2-xSex, which undergoes a superconducting transition in the nearly commensurate charge density wave phase. Advanced electron microscopy investigations reveal that such an ordered superstructure forms only in the x area, where the superconductivity manifests, and is destructible to the occurrence of the Mott metal-insulator transition. The present findings provide a novel dimension in understanding the relationship between lattice and electronic degrees of freedom.

  10. Extended and quasi-continuous tuning of quantum cascade lasers using superstructure gratings and integrated heaters

    SciTech Connect

    Bidaux, Yves; Bismuto, Alfredo Tardy, Camille; Terazzi, Romain; Gresch, Tobias; Blaser, Stéphane; Muller, Antoine; Faist, Jerome

    2015-11-30

    In this work, we demonstrate broad electrical tuning of quantum cascade lasers at 9.25 μm, 8.5 μm, and 4.4 μm in continuous wave operation using Vernier-effect distributed Bragg reflectors based on superstructure gratings. Integrated micro-heaters allow to switch from one Vernier channel to the other, while predictable and mode-hop free tuning can be obtained in each channel modulating the laser current with a side mode suppression ratio as high as 30 dB. The resulting device behaves effectively as a switchable multicolour tunable source. Tuning up to 6.5% of the central wavelength is observed. To prove the importance of the developed devices for high resolution molecular spectroscopy, a N{sub 2}O absorption spectrum has been measured.

  11. Extended and quasi-continuous tuning of quantum cascade lasers using superstructure gratings and integrated heaters

    NASA Astrophysics Data System (ADS)

    Bidaux, Yves; Bismuto, Alfredo; Tardy, Camille; Terazzi, Romain; Gresch, Tobias; Blaser, Stéphane; Muller, Antoine; Faist, Jerome

    2015-11-01

    In this work, we demonstrate broad electrical tuning of quantum cascade lasers at 9.25 μm, 8.5 μm, and 4.4 μm in continuous wave operation using Vernier-effect distributed Bragg reflectors based on superstructure gratings. Integrated micro-heaters allow to switch from one Vernier channel to the other, while predictable and mode-hop free tuning can be obtained in each channel modulating the laser current with a side mode suppression ratio as high as 30 dB. The resulting device behaves effectively as a switchable multicolour tunable source. Tuning up to 6.5% of the central wavelength is observed. To prove the importance of the developed devices for high resolution molecular spectroscopy, a N2O absorption spectrum has been measured.

  12. Regiospecific Hetero-Assembly of DNA-Functionalized Plasmonic Upconversion Superstructures

    PubMed Central

    2015-01-01

    We report a novel strategy for regiospecific hetero-assembly of DNA-modified gold nanoparticles (DNA-AuNPs) onto upconversion nanoparticles (UCNPs) into hybrid lab-on-a-particle systems. The DNA-AuNPs have been assembled onto the hexagonal plate-like UCNPs with well-regulated stoichiometry and controlled organization onto the different facets of UCNP, forming various addressable superstructures. The fine-tuning of stoichiometry and organization is realized by biorecognition specificity of DNA toward specific crystal facets of UCNPs. Such a hetero-assembled DNA-AuNP/UCNP system maintains both plasmonic resonance of AuNPs and fluorescent properties of UCNPs, allowing targeted dual-modality imaging of cancer cells using an aptamer. PMID:25853565

  13. The stacked ISW signal of rare superstructures in ΛCDM

    SciTech Connect

    Flender, Samuel; Hotchkiss, Shaun; Nadathur, Seshadri E-mail: shaun.hotchkiss@helsinki.fi

    2013-02-01

    A detection of the stacked integrated Sachs-Wolfe (ISW) signal in the CMB of rare superstructures identified in the SDSS Luminous Red Galaxy catalogue has been reported at very high statistical significance. The magnitude of the observed signal has previously been argued to be more than 3σ larger than the theoretical ΛCDM expectation. However, this calculation was made in the linear approximation, and relied on assumptions that may potentially have caused the ΛCDM expectation to be underestimated. Here we update the theoretical model calculation and compare it with an analysis of ISW maps obtained from N-body simulations of a ΛCDM universe. The differences between model predictions and the map analyses are found to be small and cannot explain the discrepancy with observation, which remains at > 3σ significance. We discuss the cosmological significance of this anomaly and speculate on the potential of alternative models to explain it.

  14. Stability of inhomogeneous superstructures from renormalized mean-field theory of the t-J model

    NASA Astrophysics Data System (ADS)

    Poilblanc, Didier

    2005-08-01

    Using the t-J model (which can also include Coulomb repulsion) and the “plain vanilla” renormalized mean-field theory of Zhang, [Supercond. Sci. Technol. 1, 36 (1988)], stability of inhomogeneous 4a×4a superstructures, such as those observed in cuprates superconductors around 1/8 hole doping is investigated. We find a nonuniform 4a×4a bond order wave involving simultaneously small (˜10-2t) inhomogeneous staggered plaquette currents as well as a small charge-density modulation similar to pair density wave order. On the other hand, no supersolid phase involving a decoupling in the superconducting particle-particle channel is found.

  15. Regiospecific Hetero-Assembly of DNA-Functionalized Plasmonic Upconversion Superstructures.

    PubMed

    Li, Le-Le; Lu, Yi

    2015-04-29

    We report a novel strategy for regiospecific hetero-assembly of DNA-modified gold nanoparticles (DNA-AuNPs) onto upconversion nanoparticles (UCNPs) into hybrid lab-on-a-particle systems. The DNA-AuNPs have been assembled onto the hexagonal plate-like UCNPs with well-regulated stoichiometry and controlled organization onto the different facets of UCNP, forming various addressable superstructures. The fine-tuning of stoichiometry and organization is realized by biorecognition specificity of DNA toward specific crystal facets of UCNPs. Such a hetero-assembled DNA-AuNP/UCNP system maintains both plasmonic resonance of AuNPs and fluorescent properties of UCNPs, allowing targeted dual-modality imaging of cancer cells using an aptamer. PMID:25853565

  16. Hydrothermally synthesized Copper Oxide (CuO) superstructures for ammonia sensing.

    PubMed

    Bhuvaneshwari, S; Gopalakrishnan, N

    2016-10-15

    According to environmental protection agencies (EPA), the emission threshold of NH3 in air is 1000kg/yr which is now about 20Tg/yr. Hence, there is a rapid increase in need of NH3 sensors to timely detect and control NH3 emissions. Metal oxide nanostructures such as CuO with special features are potential candidates for NH3 sensing. In the present study, morphology controlled 3-dimensional CuO superstructures were synthesized by surfactant-free hydrothermal method for NH3 detection. In addition to conventional hydrothermal method where water as solvent, a modified approach using a mixture of water and ethylene glycol (EG) was used as solvent to control the growth process. Hierarchical superstructures namely, snowflake-like, flower-like, hollow-sphere-like and urchin-like feature with particle dimensions ranging from 0.3 to 1μm were obtained by varying water/EG ratio and reaction temperature. The synthesized nanostructures exhibited morphology dependent luminescence and gas sensing properties. The surface area and pore distribution determined by BET surface analysis also largely influenced by the presence of EG in the reaction system. The average pore diameter enhanced from 6nm to 14nm by the addition of 10ml EG as solvent. The room temperature ammonia sensing behavior of all samples was studied using an indigenous gas sensing set-up. It was found that hollow-sphere like CuO nanostructures showed a maximum sensitivity of 150% towards 600ppm ammonia with a response and recovery time of 6min. The hydrothermal synthesis strategy reported here has the advantage of producing shape controlled hierarchical materials are highly suitable for various technological applications. PMID:27416288

  17. Fe-species-loaded mesoporous MnO2 superstructural requirements for enhanced catalysis.

    PubMed

    Huang, Ruting; Liu, Yanyu; Chen, Zhiwen; Pan, Dengyu; Li, Zhen; Wu, Minghong; Shek, Chan-Hung; Wu, C M Lawrence; Lai, Joseph K L

    2015-02-25

    In this work, a novel catalyst, Fe-species-loaded mesoporous manganese dioxide (Fe/M-MnO2) urchinlike superstructures, has been fabricated successfully in a two-step technique. First, mesoporous manganese dioxide (M-MnO2) urchinlike superstructures have been synthesized by a facile method on a soft interface between CH2Cl2 and H2O without templates. Then the M-MnO2-immobilized iron oxide catalyst was obtained through wetness impregnation and calcination. Microstructural analysis indicated that the M-MnO2 was composed of urchinlike hollow submicrospheres assembled by nanorod building blocks with rich mesoporosity. The Fe/M-MnO2 retained the hollow submicrospheres, which were covered by hybridized composites with broken and shortened MnO2 nanorods. Energy-dispersive X-ray microanalysis was used to determine the availability of Fe loading processes and the homogeneity of Fe in Fe/M-MnO2. Catalytic performances of the M-MnO2 and Fe/M-MnO2 were evaluated in catalytic wet hydrogen peroxide oxidation of methylene blue (MB), a typical organic pollutant in dyeing wastewater. The catalytic degradation displayed highly efficient discoloration of MB when using the Fe/M-MnO2 catalyst, e.g., ca. 94.8% of MB was decomposed when the reaction was conducted for 120 min. The remarkable stability of this Fe/M-MnO2 catalyst in the reaction medium was confirmed by an iron leaching test and reuse experiments. Mechanism analysis revealed that the hydroxyl free radical was responsible for the removal of MB and catalyzed by M-MnO2 and Fe/M-MnO2. MB was transformed into small organic compounds and then further degraded into CO2 and H2O. The new insights obtained in this study will be beneficial for the practical applications of heterogeneous catalysts in wastewater treatments. PMID:25626157

  18. Molecular mechanism of plasma sterilization in solution with the reduced pH method: importance of permeation of HOO radicals into the cell membrane

    NASA Astrophysics Data System (ADS)

    Takai, Eisuke; Ikawa, Satoshi; Kitano, Katsuhisa; Kuwabara, Junpei; Shiraki, Kentaro

    2013-07-01

    Sterilization of certain infected areas of the human body surface is necessary for dental and surgical therapies. Because the blood is filled with body fluid, sterilization in solution is essential. In vitro solution sterilization has been successively carried out using a combination of low-temperature atmospheric-pressure plasma and the reduced pH method, where the solution is sufficiently acidic. Here, we show the molecular mechanism of such plasma sterilization in solution based on microbiology. Three kinds of bacteria were inactivated by plasma treatment under various pH conditions. The theoretical and experimental models revealed that the sterilization was characterized by the concentration of hydroperoxy radicals (HOO·), which were dependent on the pH value. Bacterial inactivation rates were proportional to the HOO· concentrations calculated by the theoretical model. To evaluate the penetration of radicals into the cell membrane, a bacterial model using dye-included micelles was used. Decolouration rates of the model were also in proportion with the calculated HOO· concentrations. These results indicate that the key species for plasma sterilization were hydroperoxy radicals. More importantly, the high permeation of hydroperoxy radicals into the cell membrane plays a key role for efficient bactericidal inactivation using the reduced pH method.

  19. Application of Drag-Reducing Polymer Solutions as Test Fluids for In Vitro Evaluation of Potential Blood Damage in Blood Pumps

    PubMed Central

    Daly, Amanda R.; Sobajima, Hideo; Olia, Salim E.; Takatani, Setsuo; Kameneva, Marina V.

    2011-01-01

    In vitro evaluation of the potential of a circulatory-assist device to damage blood cells has generally been performed using blood from various species. Problems with this approach include the variability of blood sensitivity to mechanical stress in different species, preparation of blood including the adjustment of hematocrit to a standard value, changes in the mechanical properties of blood that occur during storage, and necessity to pool blood samples to obtain an adequate amount of blood for in vitro circulating systems. We investigated whether the mechanical degradation of a drag-reducing polymer (DRP) solution resulting in the loss of drag-reducing ability can indicate the degree of shear-induced blood damage within blood pumps. DRP solution (polyethylene oxide, 4,500 kDa, 1,000 ppm) or porcine blood were driven through a turbulent flow system by a centrifugal pump, either the Bio-Pump BPX-80 (Medtronic, Inc.) or CentriMag (Levitronix LLC) at a constant pressure gradient of 300 mm Hg for 120 minutes. DRP mechanical degradation was evaluated by reduction of flow rate and solution viscosity. A proposed index of DRP mechanical degradation (PDI) is similar to the normalized index of hemolysis (NIH) typically used to quantify the results of in vitro testing of blood pumps. Results indicate that the mechanical degradation of DRP solutions may provide a sensitive standard method for the evaluation of potential blood trauma produced by blood pumps without the use of blood. PMID:20019596

  20. Survey of reducing agents for the synthesis of tetraphenylarsonium oxotechnetiumbis(ethanedithiolate) from (/sup 99/Tc)pertechnetate in aqueous solution

    SciTech Connect

    Jones, A.G.; Orvig, C.; Trop, H.S.; Davison, A.; Davis, M.A.

    1980-03-01

    We have studied the effectiveness of various reducing agents in the production of the well-characterized complex (/sup 99/TcO(SCH/sub 2/CH/sub 2/S)/sub 2/)/sup -/ from pertechnetate and ethanedithiol in aqueous solution. The reductants tested included sodium dithionite, hypophosphorous acid, formamidine sulfinic acid, dithiothreitol, hydrazine, and hydroxylamine. Of these, only sodium dithionite in the pH range 11 to 13 was found to give quantitative yields of the required technetium complex.

  1. Reduced in vivo ocular surface toxicity with polyquad-preserved travoprost versus benzalkonium-preserved travoprost or latanoprost ophthalmic solutions.

    PubMed

    Liang, Hong; Brignole-Baudouin, Françoise; Riancho, Luisa; Baudouin, Christophe

    2012-01-01

    The study used a validated acute in vivo model to compare a new formulation of travoprost 0.004% ophthalmic solution(travoprost PQ), preserved with polyquaternium-1 (PQ), with commercially available formulations of benzalkonium-chloride(BAK)-preserved travoprost 0.004% ophthalmic solution(travoprost BAK) and BAK-preserved latanoprost 0.005%ophthalmic solution (latanoprost BAK). Adult male New Zealand albino rabbits (n = 36) were randomly divided into 6 groups. Phosphate-buffered saline (PBS), 0.001% PQ, 0.015% BAK, travoprost PQ, travoprost BAK or latanoprost BAK were applied onto rabbit eyes as 1 drop, for 15 times at 5-min intervals.The ocular surface reactions were investigated at hour 4 and day 1 using slitlamp examination; in vivo confocal microscopy (IVCM) for cornea, limbus and conjunctiva/conjunctiva-associated lymphoid tissue, conjunctival impression cytology and standard immunohistology in cryosections for detecting CD45+ infiltrating cells and MUC-5AC-labeled cells. PBS, PQ and travoprost PQ did not induce obvious irritation by clinical observation, changes in microstructures of the whole ocular surface as measured by IVCM analysis,inflammatory infiltration or cell damage as measured by impression cytology, altered levels of goblet cell counts or numerous CD45+ cells in the cornea. In contrast, all BAK-containing products induced diffuse conjunctival hyperemia and chemosis, abnormal changes in the ocular surface microstructure,significant total ocular surface toxicity scores,damaged epithelial cells, inflammatory cell infiltration and decreased goblet cell density. Travoprost PQ did not elicitocular surface toxicity when administered to rabbit eyes.These results suggest a greater safety advantage for the ocular surface of patients receiving chronic glaucoma treatment with PQ-preserved drugs. PMID:22473057

  2. The combination of mannitol and albumin in the priming solution reduces positive intraoperative fluid balance during cardiopulmonary bypass.

    PubMed

    Jenkins, I R; Curtis, A P

    1995-09-01

    During cardiopulmonary bypass (CPB) an adequate reservoir volume is maintained by the addition of crystalloid, colloid or packed cells to the reservoir. This volume contributes to the overall perioperative positive fluid balance. We studied the effect of the preoperative addition of either 75 g albumin, or 50 g mannitol followed by 50 g at commencement of rewarming or both of the above to a bypass circuit prime of lactated Ringer's solution (LR) on intraoperative fluid balance, postoperative indices of oxygenation and time to extubation. The study was a prospective, randomized, single-blinded controlled trial of 103 patients undergoing cardiac surgery requiring CPB. There was a large and highly significant reduction in volume of fluid added to the reservoir during CPB (2137 +/- 1499 ml versus 144 +/- 230 ml), the fluid balance during bypass, including prime volume (3236 +/- 650 ml versus 5876 +/- 1465 ml), and perioperative fluid balance (4470 +/- 936 ml versus 7023 +/- 1760 ml) in the group receiving both mannitol and albumin in the pump prime compared with the group receiving only lactated Ringer's solution. There were no differences between the groups with respect to both measured indices of oxygenation measured on return to ICU (alveolar-arterial oxygen tension difference (DA-aO2) or arterial oxygen tension to inspired oxygen fraction ratio (PaO2/FiO2), or time from ICU admission to extubation. PMID:8601041

  3. Hyaluronic Acid (800 kDa) Supplementation of University of Wisconsin Solution Improves Viability of Osteochondral Grafts and Reduces Matrix Metalloproteinase Expression during Cold Preservation

    PubMed Central

    Yamada, Takuya; Uchida, Kentaro; Onuma, Kenji; Inoue, Gen; Aikawa, Jun; Takano, Shotaro; Sekiguchi, Hiroyuki; Fujimaki, Hisako; Miyagi, Masayuki; Takaso, Masashi

    2015-01-01

    Osteochondral allografting is a promising option for the treatment of large cartilage defects. However, because the cell viability of osteochondral tissues (OCTs) gradually reduces during storage at 4°C, methods for maintaining the cell viability of fresh OCTs are needed to improve transplantation outcomes. Here, we evaluated whether the supplementation of preservation solution with one of three different molecular weight forms of hyaluronic acid (HA) improved the viability of rat OCTs during long-term cold storage. The supplementation of University of Wisconsin (UW) solution with 800 kDa significantly improved the cell viability of OCT after 14 days at 4°C compared to nonsupplemented UW solution. In contrast, UW solution supplemented with either 1900 or 6000 kDa HA did not markedly improve the cell viability of the OCT. Real-time PCR analysis revealed that the levels of matrix metalloproteinases 2, 3, and 9 were significantly decreased in OCT stored in UW solution supplemented with 800 kDa HA. Although further studies in human OCT are warranted, these findings demonstrate that the use of 800 kDa HA in place of serum may be a suitable approach for the long-term preservation of osteochondral allografts designated for the repair of large cartilage defects in the clinical setting. PMID:26199955

  4. Solution of resource allocation problem for identification of cost-effective measures to reduce nuclear proliferation risks

    SciTech Connect

    Andrianov, A.; Kuptsov, I.

    2013-07-01

    This report presents a methodology of selection of cost-effective measures to reduce nuclear proliferation risks. The methodology relies on a graded security model used in practice in different applications. The method is based on the controlled finite Markov chain approach set in combination with discrete dynamic programming and MCDM (Multi Criteria Decision Making) techniques that enables the expert to select the cost-effective measures to reduce nuclear proliferation risks depending on availability of resources. The analysis performed with different number of possible measures confirms the conclusions that the implementation of extra-large costs may not produce the required effect, and the increase in resources above a certain level does not appear sensitive. Diversification in improving the effectiveness of other measures seems more rational and efficient for the whole system than the unlimited improvement of the effectiveness of only one measure.

  5. Pretreatment of BMSCs with TZD solution decreases the proliferation rate of MCF-7 cells by reducing FGF4 protein expression

    PubMed Central

    KHOO, BOON-YIN; NADARAJAN, KALPANAH; SHIM, SIANG-YIAN; MISWAN, NOORIZAN; ZANG, CHUAN-BING; POSSINGER, KURT; ELSTNER, ELENA

    2016-01-01

    The present study aimed to investigate the effects of bone marrow-derived mesenchymal stem cells (BMSCs) that had been pretreated with pioglitazone and/or rosiglitazone on the growth and proliferation rate of MCF-7 cells. The adhesive interaction between the BMSCs and the MCF-7 cancer cells revealed that the pretreatment of BMSCs with a combination of two types of thiazolidinedione drug reduced the growth and proliferation rate of the MCF-7 cells. The proliferation rate of the MCF-7 cells could also be reduced by the non-adhesive interaction of the cancer cells with BMSCs pretreated with pioglitazone and/or rosiglitazone. The growth and proliferation rate reduction effects on the MCF-7 cells may be attributed to the reduction in the protein level of fibroblast growth factor 4 (FGF4) in the conditioned medium of the pretreated BMSCs. The evidence that the low protein level of FGF4 in the conditioned medium of the pretreated BMSCs perturbed the proliferation rate of the MCF-7 cells by reducing the levels of Ki-67 and proliferating cell nuclear antigen transcripts in the cancer cells was also demonstrated in the present study using a FGF4-neutralizing antibody. All the above findings demonstrate that future studies on the correlation between FGF4 and pretreated BMSCs would be beneficial. PMID:26934829

  6. Bathing in a magnesium-rich Dead Sea salt solution improves skin barrier function, enhances skin hydration, and reduces inflammation in atopic dry skin.

    PubMed

    Proksch, Ehrhardt; Nissen, Hans-Peter; Bremgartner, Markus; Urquhart, Colin

    2005-02-01

    Magnesium salts, the prevalent minerals in Dead Sea water, are known to exhibit favorable effects in inflammatory diseases. We examined the efficacy of bathing atopic subjects in a salt rich in magnesium chloride from deep layers of the Dead Sea (Mavena(R) Dermaline Mg(46) Dead Sea salt, Mavena AG, Belp, Switzerland). Volunteers with atopic dry skin submerged one forearm for 15 min in a bath solution containing 5% Dead Sea salt. The second arm was submerged in tap water as control. Before the study and at weeks 1-6, transepidermal water loss (TEWL), skin hydration, skin roughness, and skin redness were determined. We found one subgroup with a normal and one subgroup with an elevated TEWL before the study. Bathing in the Dead Sea salt solution significantly improved skin barrier function compared with the tap water-treated control forearm in the subgroup with elevated basal TEWL. Skin hydration was enhanced on the forearm treated with the Dead Sea salt in each group, which means the treatment moisturized the skin. Skin roughness and redness of the skin as a marker for inflammation were significantly reduced after bathing in the salt solution. This demonstrates that bathing in the salt solution was well tolerated, improved skin barrier function, enhanced stratum corneum hydration, and reduced skin roughness and inflammation. We suggest that the favorable effects of bathing in the Dead Sea salt solution are most likely related to the high magnesium content. Magnesium salts are known to bind water, influence epidermal proliferation and differentiation, and enhance permeability barrier repair. PMID:15689218

  7. Innovative solutions: the effect of a workshop on reducing the experience of moral distress in an intensive care unit setting.

    PubMed

    Beumer, Catherine M

    2008-01-01

    Moral distress is the knowledge of the ethically appropriate action to take but the inability to act upon it. This phenomenon is one experienced in the critical care setting. To help staff members cope with moral distress, a team conducted workshops at one facility to help the staff identify and cope with this distress. The workshop consisted of discussions of distressing situations in the intensive care unit, didactic information on moral distress, formulation of an individual plan to reduce stress, and strategies to deal with moral distress in the intensive care unit. This article discusses the workshop and its effect on participants' coping with moral distress. PMID:18953194

  8. Boost the electron mobility of solution-grown organic single crystals via reducing the amount of polar solvent residues

    DOE PAGESBeta

    Xue, Guobiao; Xin, Huolin L.; Wu, Jiake; Fan, Congcheng; Liu, Shuang; Huang, Zhuoting; Liu, Yujing; Shan, Bowen; Miao, Qian; Chen, Hongzheng; et al

    2015-10-29

    Enhancing electron transport to match with the development in hole transport is critical for organic electronics in the future. As electron motion is susceptible to extrinsic factors, seeking these factors and avoiding their negative effects have become the central challenge. Here, the existence of polar solvent residues in solution-grown single-crystals of 6,13-bis(triisopropylsilylethynyl)-5,7,12,14-tetraazapentacene is identified as a factor detrimental to electron motion. Field-effect transistors of the crystals exhibit electron mobility boosted by about 60% after the residues are removed. The average electron mobility reaches up to 8.0 ± 2.2 cm2 V–1 s–1 with a highest value of 13.3 cm2 V–1 s–1;more » these results are significantly higher than those obtained previously for the same molecule (1.0–5.0 cm2 V–1 s–1). Furthermore, the achieved mobility is also higher than the maximum reported electron mobility for organic materials (11 cm2 V–1 s–1). As a result, this work should greatly accelerate the advancement of organic electron-transporting materials.« less

  9. Bowl-shaped superstructures of CdSe nanocrystals with the narrow-sized distribution for a high-performance photoswitch

    NASA Astrophysics Data System (ADS)

    Zhang, Bo; Shen, Yongtao; Feng, Yiyu; Qin, Chengqun; Huang, Zhengcheng; Feng, Wei

    2015-07-01

    The bowl-shaped CdSe superstructure with a diameter of 1-2 μm and the thickness of hundreds nanometers was synthesized using Cd(SA)2 and Se powder in an organic phase. The CdSe nanocrystals for assembling superstructures had a narrow-sized distribution indicated by a sharp emission peak in the photoluminescence (PL) spectrum. Moreover, an organic-inorganic hybrid photoswitch based on CdSe superstructures were fabricated. The device exhibited an on/off switching ratio of ∼100 with a good cycling stability. The excellent photo-responsible performance illustrates that the superstructures hold a great promise for the application of photoelectric devices.

  10. Reduced-order wavelet-Galerkin solution for the coupled, nonlinear stochastic response of slender buildings in transient winds

    NASA Astrophysics Data System (ADS)

    Le, Thai-Hoa; Caracoglia, Luca

    2015-05-01

    A tall building is prone to wind-induced stochastic vibration, originating from complex fluid-structure interaction, dynamic coupling and nonlinear aerodynamic phenomena. The loading induced by extreme wind events, such as "downburst storms", hurricanes and tornadoes is naturally transient and nonstationary in comparison with the hypothesis of stationary wind loads, used in both structural engineering research and practice. Time-domain integration methods, widely applied for solving nonlinear differential equations, are hardly applicable to the analysis of coupled, nonlinear and stochastic response of tall buildings under transient winds. Therefore, the investigation of alternative and computationally-efficient simulation methods is important. This study employs the wavelet-Galerkin (WG) method to achieve this objective, by examining the stochastic dynamic response of two tall building models subject to stationary and transient wind loads. These are (1) a single-degree-of-freedom equivalent model of a tall structure and (2) a multi-degree-of-freedom reduced-order full building model. Compactly supported Daubechies wavelets are used as orthonormal basis functions in conjunction with the Galerkin projection scheme to decompose and transform the coupled, nonlinear differential equations of the two models into random algebraic equations in the wavelet domain. Methodology, feasibility and applicability of the WG method are investigated in some special cases of stiffness nonlinearity (Duffing type) and damping nonlinearity (Van-der-Pol type) for the single-degree-of-freedom model. For the reduced-order tall building model the WG method is used to solve for dynamic coupling, aerodynamics and transient wind load effects. Computation of "connection coefficients", effects of boundary conditions, wavelet resolution and wavelet order are examined in order to adequately replicate the dynamic response. Realizations of multivariate stationary and transient wind loads for the

  11. An economical solution for reducing NO{sub x} emissions from cell burner boilers firing pulverized coal

    SciTech Connect

    Penterson, C.A.; Dorai, X.A.

    1995-10-01

    Over 12% (26,000 MWe) of the US generating capacity is produced from utility boilers equipped with pre-New Source Performance Standard (NSPS) cell burners. These burners, manufactured in the 1950`s and 60`s, rapidly mix the pulverized coal and combustion air resulting in highly turbulent and efficient combustion. Unfortunately, NO{sub x} emissions produced by this type of firing configuration are extremely high typically averaging 1.0 to 1.8 lb/10{sup 6} Btu. This paper presents the results of retrofitting American Electric Power`s Muskingum River Unit 5, a 600 MWe supercritical cell burner boiler with Riley low NO{sub x} CCV{trademark} burners. Results of this project successfully demonstrated the ability to reduce NO{sub x} emissions greater than 50% without the requirement for overfire air (OFA), off stoichiometric firing, burner respacing, mill system or coal piping changes or pressure part modifications. Emissions and boiler performance results are presented along with the typical costs for this type of retrofit.

  12. Effectiveness of egg immersion in aqueous solutions of thiamine and thiamine analogs for reducing early mortality syndrome

    USGS Publications Warehouse

    Brown, S.B.; Brown, L.R.; Brown, M.; Moore, K.; Villella, M.; Fitzsimons, J.D.; Williston, B.; Honeyfield, D.C.; Hinterkopf, J.P.; Tillitt, D.E.; Zajicek, J.L.; Wolgamood, M.

    2005-01-01

    Protocols used for therapeutic thiamine treatments in salmonine early mortality syndrome (EMS) were investigated in lake trout Salvelinus namaycush and coho salmon Oncorhynchus kisutch to assess their efficacy. At least 500 mg of thiamine HCl/L added to egg baths was required to produce a sustained elevation of thiamine content in lake trout eggs. Thiamine uptake from egg baths was not influenced by a pH ranging from 5.5 to 7.5 or by a water hardness between 2 and 200 mg CaCO3/L. There was poorer thiamine uptake when initial thiamine levels were low, suggesting that current treatment regimes may not be as effective when thiamine levels are severely depressed and that higher treatment doses are necessary. Exposure of eggs to the more lipid-soluble thiamine analog allithiamine (1,000 mg/L) during water hardening increased egg thiamine levels by 1.5-2.5 nmol/g and was completely effective at reversing EMS. Another more lipid-soluble thiamine analog, benfotiamine (100 mg/L), reduced EMS but did not produce detectable increases in egg thiamine content. Although benfotiamine may be more effective than thiamine at mitigating EMS, it is more expensive than thiamine HCl or allithiamine. In addition, there still needs to be a more thorough examination of dose-response relationships. We conclude that allithiamine is an alternative to the use of thiamine in egg baths as a therapeutic treatment for salmonid EMS. ?? Copyright by the American Fisheries Society 2005.

  13. Portion size me: plate-size induced consumption norms and win-win solutions for reducing food intake and waste.

    PubMed

    Wansink, Brian; van Ittersum, Koert

    2013-12-01

    Research on the self-serving of food has empirically ignored the role that visual consumption norms play in determining how much food we serve on different sized dinnerware. We contend that dinnerware provides a visual anchor of an appropriate fill-level, which in turn, serves as a consumption norm (Study 1). The trouble with these dinnerware-suggested consumption norms is that they vary directly with dinnerware size--Study 2 shows Chinese buffet diners with large plates served 52% more, ate 45% more, and wasted 135% more food than those with smaller plates. Moreover, education does not appear effective in reducing such biases. Even a 60-min, interactive, multimedia warning on the dangers of using large plates had seemingly no impact on 209 health conference attendees, who subsequently served nearly twice as much food when given a large buffet plate 2 hr later (Study 3). These findings suggest that people may have a visual plate-fill level--perhaps 70% full--that they anchor on when determining the appropriate consumption norm and serving themselves. Study 4 suggests that the Delboeuf illusion offers an explanation why people do not fully adjust away from this fill-level anchor and continue to be biased across a large range of dishware sizes. These findings have surprisingly wide-ranging win-win implications for the welfare of consumers as well as for food service managers, restaurateurs, packaged goods managers, and public policy officials. PMID:24341317

  14. Role of the Pinning Points in epitaxial Graphene Moiré Superstructures on the Pt(111) Surface

    PubMed Central

    Martínez, José I.; Merino, Pablo; Pinardi, Anna L.; Gonzalo, Otero-Irurueta; López, María F.; Méndez, Javier; Martín-Gago, José A.

    2016-01-01

    The intrinsic atomic mechanisms responsible for electronic doping of epitaxial graphene Moirés on transition metal surfaces is still an open issue. To better understand this process we have carried out a first-principles full characterization of the most representative Moiré superstructures observed on the Gr/Pt(111) system and confronted the results with atomically resolved scanning tunneling microscopy experiments. We find that for all reported Moirés the system relaxes inducing a non-negligible atomic corrugation both, at the graphene and at the outermost platinum layer. Interestingly, a mirror “anti-Moiré” reconstruction appears at the substrate, giving rise to the appearance of pinning-points. We show that these points are responsible for the development of the superstructure, while charge from the Pt substrate is injected into the graphene, inducing a local n-doping, mostly localized at these specific pinning-point positions. PMID:26852920

  15. Role of the Pinning Points in epitaxial Graphene Moiré Superstructures on the Pt(111) Surface.

    PubMed

    Martínez, José I; Merino, Pablo; Pinardi, Anna L; Gonzalo, Otero-Irurueta; López, María F; Méndez, Javier; Martín-Gago, José A

    2016-01-01

    The intrinsic atomic mechanisms responsible for electronic doping of epitaxial graphene Moirés on transition metal surfaces is still an open issue. To better understand this process we have carried out a first-principles full characterization of the most representative Moiré superstructures observed on the Gr/Pt(111) system and confronted the results with atomically resolved scanning tunneling microscopy experiments. We find that for all reported Moirés the system relaxes inducing a non-negligible atomic corrugation both, at the graphene and at the outermost platinum layer. Interestingly, a mirror "anti-Moiré" reconstruction appears at the substrate, giving rise to the appearance of pinning-points. We show that these points are responsible for the development of the superstructure, while charge from the Pt substrate is injected into the graphene, inducing a local n-doping, mostly localized at these specific pinning-point positions. PMID:26852920

  16. Solution structure of the reduced form of human peroxiredoxin-6 elucidated using zero-length chemical cross-linking and homology modelling.

    PubMed

    Rivera-Santiago, Roland F; Harper, Sandra L; Zhou, Suiping; Sriswasdi, Sira; Feinstein, Sheldon I; Fisher, Aron B; Speicher, David W

    2015-05-15

    Peroxiredoxin-6 (PRDX6) is an unusual member of the peroxiredoxin family of antioxidant enzymes that has only one evolutionarily conserved cysteine. It reduces oxidized lipids and reactive oxygen species (ROS) by oxidation of the active-site cysteine (Cys(47)) to a sulfenic acid, but the mechanism for conversion back to a thiol is not completely understood. Moreover, it has phospholipase A2 (PLA2) activity in addition to its peroxidase activity. Interestingly, some biochemical data are inconsistent with a known high-resolution crystal structure of the catalytic intermediate of the protein, and biophysical data indicate that the protein undergoes conformational changes that affect enzyme activity. In order to further elucidate the solution structure of this important enzyme, we used chemical cross-linking coupled with high-resolution MS (CX-MS), with an emphasis on zero-length cross-links. Distance constraints from high confidence cross-links were used in homology modelling experiments to determine a solution structure of the reduced form of the protein. This structure was further evaluated using chemical cross-links produced by several homo-bifunctional amine-reactive cross-linking reagents, which helped to confirm the solution structure. The results show that several regions of the reduced version of human PRDX6 are in a substantially different conformation from that shown for the crystal structure of the peroxidase catalytic intermediate. The differences between these two structures are likely to reflect catalysis-related conformational changes. These studies also demonstrate that CX-MS using zero-length cross-linking is a powerful strategy for probing protein conformational changes that is complementary to alternative methods such as crystallographic, NMR and biophysical studies. PMID:25748205

  17. Clinical use of an epinephrine-reduced (1/400,000) articaine solution in short-time dental routine treatments--a multicenter study.

    PubMed

    Daubländer, Monika; Kämmerer, Peer W; Willershausen, Brita; Leckel, Michael; Lauer, Hans-Christoph; Buff, Siegmar; Rösl, Benita

    2012-08-01

    The addition of epinephrine in dental local anaesthesia results in a longer and deeper anaesthesia under almost ischemic conditions. For short-time dental treatments, epinephrine-reduced anaesthetics may offer shorter and more individual anaesthesia with reduced potential side effects. The aim of this study was a clinical evaluation of anaesthetic potency and adverse effects of an epinephrine-reduced articaine formulation in dental patients undergoing short-time routine treatment. In a prospective clinical, not interventional, study between January 2008 and February 2009, 908 patients undergoing short-time dental treatment in five medical centers were anaesthetized with 4% articaine 1:400,000 epinephrine (Ubistesin, 3M/ESPE, Seefeld, Germany). Efficacy and safety in clinical use were evaluated. A follow-up after 1 day was conducted by telephone survey. A mean amount of 1.3-ml anaesthetic solution was needed to achieve a complete or sufficient anaesthesia in 97% (n = 876) of cases. A second injection had to be done in 3.7% (n = 34) before and in 11.9% (n = 108) during treatment. Here, the second injection had to be applied after a mean of 48.6 min. The mean duration of soft tissue anaesthesia after infiltration was 146.6 min, after nerve block 187.7 min. The painful treatment took a mean of 50.2 min and the total treatment time summed up to 68.8 min. In 1.7% cases (n = 15), unwanted side effects were observed. The results indicate that a lower concentration of epinephrine in combination with the 4% articaine solution leads to a high success rate of efficacy. The clinical use of a 4% articaine 1:400,000 epinephrine solution can be stated as safe and effective in short dental routine treatments. Reconsiderations concerning limitations of indication or additional contraindications are not necessary. PMID:21861074

  18. Polypyrrole-enveloped Pd and Fe3O4 nanoparticle binary hollow and bowl-like superstructures as recyclable catalysts for industrial wastewater treatment.

    PubMed

    Zhang, Xue; Lin, Min; Lin, Xiaoying; Zhang, Chunting; Wei, Haotong; Zhang, Hao; Yang, Bai

    2014-01-01

    Metal and metal-oxide nanoparticles (NPs) are promising catalysts for dye degradation in wastewater treatment despite the challenges of NP recovery and recycling. In this study, water-dispersible NP superstructures with spherical morphology were constructed from hydrophobic Pd and Fe3O4 NPs by virtue of the oil droplets in an oil-in-water microemulsion as templates. Control of the evaporation rate of organic solvents in the oil droplets produces solid, hollow, and bowl-like superstructures. The component Fe3O4 and in particular Pd NPs can catalyze H2O2 degradation to create hydroxyl radicals and therewith degrade various dyes, and the magnetic Fe3O4 NPs also permit recycling of the superstructures with a magnet. Because the hollow and bowl-like superstructures increase the contact area of the NPs with their surroundings in comparison to solid superstructures, the catalytic activity is greatly enhanced. To improve the structural stability, the superstructures were further enveloped with a thin polypyrrole (PPy) shell, which does not weaken the catalytic activity. Because the current method is facile and feasible to create recyclable catalysts, it will promote the practicability of NP catalysts in treating industrial polluted water. PMID:24266702

  19. The Z' = 12 superstructure of Λ-cobalt(III) sepulchrate trinitrate governed by C-H...O hydrogen bonds.

    PubMed

    Dey, Somnath; Schönleber, Andreas; Mondal, Swastik; Prathapa, Siriyara Jagannatha; van Smaalen, Sander; Larsen, Finn Krebs

    2016-06-01

    Λ-Cobalt(III) sepulchrate trinitrate crystallizes in P6322 with Z = 2 (Z' = 1/6) at room temperature. Slabs perpendicular to the hexagonal axis comprise molecules Co(sepulchrate) alternating with nitrate groups A and B. Coordinated by six sepulchrate molecules, highly disordered nitrate groups C are accommodated between the slabs. Here we report the fully ordered, low-temperature crystal structure of Co(sep)(NO3)3. It is found to be a high-Z' structure with Z' = 12 of the 12-fold 6a_{h}\\times\\sqrt{3}b_{h}\\times c_{h} superstructure with monoclinic symmetry P21 (c unique). Correlations between structural parameters are effectively removed by refinements within the superspace approach. Superstructure formation is governed by a densification of the packing in conjunction with ordering of nitrate group C, the latter assuming different orientations for each of the Z' = 12 independent copies in the superstructure. The Co(sep) moiety exhibits small structural variations over its 12 independent copies, while orientations of nitrate groups A and B vary less than the orientations of the nitrate group C do. Molecular packing in the superstructure is found to be determined by short C-H...H-C contacts, with H...H distances of 2.2-2.3 Å, and by short C-H...O contacts, with H...O distances down to 2.2 Å. These contacts presumably represent weak C-H...O hydrogen bonds, but in any case they prevent further densification of the structure and strengthening of weak N-H...O hydrogen bonds with observed H...O distances of 2.4-2.6 Å. PMID:27240768

  20. The Z′ = 12 superstructure of Λ-cobalt(III) sepulchrate trinitrate governed by C—H⋯O hydrogen bonds

    PubMed Central

    Dey, Somnath; Schönleber, Andreas; Mondal, Swastik; Prathapa, Siriyara Jagannatha; van Smaalen, Sander; Larsen, Finn Krebs

    2016-01-01

    Λ-Cobalt(III) sepulchrate trinitrate crystallizes in P6322 with Z = 2 (Z′ = 1/6) at room temperature. Slabs perpendicular to the hexagonal axis comprise molecules Co(sepulchrate) alternating with nitrate groups A and B. Coordinated by six sepulchrate molecules, highly disordered nitrate groups C are accommodated between the slabs. Here we report the fully ordered, low-temperature crystal structure of Co(sep)(NO3)3. It is found to be a high-Z′ structure with Z′ = 12 of the 12-fold superstructure with monoclinic symmetry P21 (c unique). Correlations between structural parameters are effectively removed by refinements within the superspace approach. Superstructure formation is governed by a densification of the packing in conjunction with ordering of nitrate group C, the latter assuming different orientations for each of the Z′ = 12 independent copies in the superstructure. The Co(sep) moiety exhibits small structural variations over its 12 independent copies, while orientations of nitrate groups A and B vary less than the orientations of the nitrate group C do. Molecular packing in the superstructure is found to be determined by short C—H⋯H—C contacts, with H⋯H distances of 2.2–2.3 Å, and by short C—H⋯O contacts, with H⋯O distances down to 2.2 Å. These contacts presumably represent weak C—H⋯O hydrogen bonds, but in any case they prevent further densification of the structure and strengthening of weak N—H⋯O hydrogen bonds with observed H⋯O distances of 2.4–2.6 Å. PMID:27240768

  1. Smart Superstructures with Ultrahigh pH-Sensitivity for Targeting Acidic Tumor Microenvironment: Instantaneous Size Switching and Improved Tumor Penetration.

    PubMed

    Li, Hong-Jun; Du, Jin-Zhi; Liu, Jing; Du, Xiao-Jiao; Shen, Song; Zhu, Yan-Hua; Wang, Xiaoyan; Ye, Xiaodong; Nie, Shuming; Wang, Jun

    2016-07-26

    The currently low delivery efficiency and limited tumor penetration of nanoparticles remain two major challenges of cancer nanomedicine. Here, we report a class of pH-responsive nanoparticle superstructures with ultrasensitive size switching in the acidic tumor microenvironment for improved tumor penetration and effective in vivo drug delivery. The superstructures were constructed from amphiphilic polymer directed assembly of platinum-prodrug conjugated polyamidoamine (PAMAM) dendrimers, in which the amphiphilic polymer contains ionizable tertiary amine groups for rapid pH-responsiveness. These superstructures had an initial size of ∼80 nm at neutral pH (e.g., in blood circulation), but once deposited in the slightly acidic tumor microenvironment (pH ∼6.5-7.0), they underwent a dramatic and sharp size transition within a very narrow range of acidity (less than 0.1-0.2 pH units) and dissociated instantaneously into the dendrimer building blocks (less than 10 nm in diameter). This rapid size-switching feature not only can facilitate nanoparticle extravasation and accumulation via the enhanced permeability and retention effect but also allows faster nanoparticle diffusion and more efficient tumor penetration. We have further carried out comparative studies of pH-sensitive and insensitive nanostructures with similar size, surface charge, and chemical composition in both multicellular spheroids and poorly permeable BxPC-3 pancreatic tumor models, whose results demonstrate that the pH-triggered size switching is a viable strategy for improving drug penetration and therapeutic efficacy. PMID:27244096

  2. Development of peptide-based methods for controlling the structures, compositions, and properties of complex nanoparticle superstructures

    NASA Astrophysics Data System (ADS)

    Song, Chengyi

    This dissertation describes the development of a nanoparticle assembly methodology based on the use of peptide conjugate molecules. The aim of this research was to explore how this methodology could be used to control the structure, metrics, and properties of product nanoparticle superstructures. Specifically, this document describes mechanistic studies aimed at understanding the key factors that govern the nanoparticle synthesis and assembly process. Using what we learned from these studies, we prepared high-quality helical nanoparticle superstructures and studied their chirooptical properties. We coupled theory and experiment to show how tuning the metrics and structure of the helices results in predictable and tailorable circular dichroism (CD) properties. We also describe how the composition of the peptide conjugate can influence both the structure of the nanoparticle assembly and detail how peptide conjugates can be utilized to prepare 'hollow' sub-100nm gold nanoparticle spheres. Finally, to expand the composition scope of the methodology, we present a new cobalt-binding peptide conjugate, which could be used to direct the synthesis and assembly of hollow CoPt nanospherical superstructures exhibiting electrocatalytic activity for methanol oxidation.

  3. Fast and low-temperature sintering of silver complex using oximes as a potential reducing agent for solution-processible, highly conductive electrodes

    NASA Astrophysics Data System (ADS)

    Yoo, Ji Hoon; Han, Dae Sang; Park, Su Bin; Chae, Jangwoo; Kim, Ji Man; Kwak, Jeonghun

    2014-11-01

    Highly conductive, solution-processed silver thin-films were obtained at a low sintering temperature of 100 °C in a short sintering time of 10 min by introducing oximes as a potential reductant for silver complex. The thermal properties and reducibility of three kinds of oximes, acetone oxime, 2-butanone oxime, and one dimethylglyoxime, were investigated as a reducing agent, and we found that the thermal decomposition product of oximes (ketones) accelerated the conversion of silver complex into highly conductive silver at low sintering temperature in a short time. Using the acetone oxime, the silver thin-film exhibited the lowest surface resistance (0.91 Ω sq-1) compared to those sing other oximes. The silver thin-film also showed a high reflectance of 97.8%, which is comparable to evaporated silver films. We also demonstrated inkjet printed silver patterns with the oxime-added silver complex inks.

  4. Synthesis of hierarchical Ni{sub 11}(HPO{sub 3}){sub 8}(OH){sub 6} superstructures based on nanorods through a soft hydrothermal route

    SciTech Connect

    Liao, Kaiming; Ni, Yonghong

    2010-02-15

    In this paper, we reported the successful synthesis of hierarchical Ni{sub 11}(HPO{sub 3}){sub 8}(OH){sub 6} superstructures based on nanorods via a facile hydrothermal route, employing NiCl{sub 2}.6H{sub 2}O and NaH{sub 2}PO{sub 2}.H{sub 2}O as the reactants in the presences of polyvinylpyrrolidone (PVP) and CH{sub 3}COONa.3H{sub 2}O. The reaction was carried out at 170 {sup o}C for 10 h. HPO{sub 3}{sup 2-} ions were provided via the dismutation reaction of H{sub 2}PO{sub 2}{sup -} ions in a weak basic solution. The as-obtained products were characterized by X-ray powder diffraction (XRD), energy dispersive spectrometry (EDS), field emission scanning electron microscopy (SEM), selected area electron diffraction (SAED) and high resolution transmission electron microscopy (HRTEM). Some factors influencing the morphology of the hierarchical Ni{sub 11}(HPO{sub 3}){sub 8}(OH){sub 6} nanorods, such as the reaction temperature, time, the amounts of PVP and CH{sub 3}COONa, and the initial concentration of Ni{sup 2+} ions, were systematically investigated. A possible growth mechanism was proposed based on experimental results.

  5. Scalable One-pot Bacteria-templating Synthesis Route toward Hierarchical, Porous-Co3O4 Superstructures for Supercapacitor Electrodes

    PubMed Central

    Shim, Hyun-Woo; Lim, Ah-Hyeon; Kim, Jae-Chan; Jang, Eunjin; Seo, Seung-Deok; Lee, Gwang-Hee; Kim, T. Doohun; Kim, Dong-Wan

    2013-01-01

    Template-driven strategy has been widely used to synthesize inorganic nano/micro materials. Here, we used a bottom-up controlled synthesis route to develop a powerful solution-based method of fabricating three-dimensional (3D), hierarchical, porous-Co3O4 superstructures that exhibit the morphology of flower-like microspheres (hereafter, RT-Co3O4). The gram-scale RT-Co3O4 was facilely prepared using one-pot synthesis with bacterial templating at room temperature. Large-surface-area RT-Co3O4 also has a noticeable pseudocapacitive performance because of its high mass loading per area (~10 mg cm−2), indicating a high capacitance of 214 F g−1 (2.04 F cm−2) at 2 A g−1 (19.02 mA cm−2), a Coulombic efficiency averaging over 95%, and an excellent cycling stability that shows a capacitance retention of about 95% after 4,000 cycles. PMID:23900049

  6. Genetic-Algorithm Discovery of a Direct-Gap and Optically Allowed Superstructure from Indirect-Gap Si and Ge Semiconductors

    SciTech Connect

    d'Avezac, M.; Luo, J. W.; Chanier, T.; Zunger, A.

    2012-01-13

    Combining two indirect-gap materials - with different electronic and optical gaps - to create a direct gap material represents an ongoing theoretical challenge with potentially rewarding practical implications, such as optoelectronics integration on a single wafer. We provide an unexpected solution to this classic problem, by spatially melding two indirect-gap materials (Si and Ge) into one strongly dipole-allowed direct-gap material. We leverage a combination of genetic algorithms with a pseudopotential Hamiltonian to search through the astronomic number of variants of Si{sub n}/Ge{sub m}/.../Si{sub p}/Ge{sub q} superstructures grown on (001) Si{sub 1-x}Ge{sub x}. The search reveals a robust configurational motif - SiGe{sub 2}Si{sub 2}Ge{sub 2}SiGe{sub n} on (001) Si{sub x}Ge{sub 1-x} substrate (x {le} 0.4) presenting a direct and dipole-allowed gap resulting from an enhanced {Gamma}-X coupling at the band edges.

  7. Mechanism of sonochemical reduction of permanganate to manganese dioxide in aqueous alcohol solutions: Reactivities of reducing species formed by alcohol sonolysis.

    PubMed

    Okitsu, Kenji; Iwatani, Masaki; Okano, Koji; Uddin, Md Helal; Nishimura, Rokuro

    2016-07-01

    The sonochemical reduction of MnO4(-) to MnO2 in aqueous solutions was investigated as a function of alcohol concentration under Ar. The rate of MnO4(-) reduction initially decreased with increasing alcohol concentration, and then increased when the alcohol concentration was increased further. The concentrations at which the reduction rates were minimum depended on the hydrophobic properties of the added alcohols under ultrasonic irradiation. At low concentrations, the alcohols acted as OH radical scavengers; at high concentrations, they acted as reductant precursors: Rab, formed by abstraction reactions of the alcohols with sonochemically formed OH radicals or H atoms, and Rpy, formed by alcohol pyrolysis under ultrasonic irradiation. The results suggest that the reactivity order of the sonochemically formed reducing species with MnO4(-) at pH 7-9 is the sum of H2O2 and H>Rpy>Rab. The peak wavelengths of MnO2 colloidal solutions formed at high 1-butanol concentrations shifted to shorter wavelengths, suggesting the formation of small particles at high 1-butanol concentrations. The rates of sonochemical reduction of MnO2 to Mn(2+) in the presence of 1-butanol were slower than that in the absence of 1-butanol, because the sonochemical formation of H2O2 and H, which act as reductants, was suppressed by 1-butanol in aqueous solutions. PMID:26964972

  8. Noble Gas (Argon and Xenon)-Saturated Cold Storage Solutions Reduce Ischemia-Reperfusion Injury in a Rat Model of Renal Transplantation

    PubMed Central

    Irani, Y.; Pype, J.L.; Martin, A.R.; Chong, C.F.; Daniel, L.; Gaudart, J.; Ibrahim, Z.; Magalon, G.; Lemaire, M.; Hardwigsen, J.

    2011-01-01

    Background Following kidney transplantation, ischemia-reperfusion injury contributes to adverse outcomes. The purpose of this study was to determine whether a cold-storage solution saturated with noble gas (xenon or argon) could limit ischemia-reperfusion injury following cold ischemia. Methods Sixty Wistar rats were randomly allocated to 4 experimental groups. Kidneys were harvested and then stored for 6 h before transplantation in cold-storage solution (Celsior®) saturated with either air, nitrogen, xenon or argon. A syngenic orthotopic transplantation was performed. Renal function was determined on days 7 and 14 after transplantation. Transplanted kidneys were removed on day 14 for histological and immunohistochemical analyses. Results Creatinine clearance was significantly higher and urinary albumin significantly lower in the argon and xenon groups than in the other groups at days 7 and 14. These effects were considerably more pronounced for argon than for xenon. In addition, kidneys stored with argon, and to a lesser extent those stored with xenon, displayed preserved renal architecture as well as higher CD-10 and little active caspase-3 expression compared to other groups. Conclusion Argon- or xenon-satured cold-storage solution preserved renal architecture and function following transplantation by reducing ischemia-reperfusion injury. PMID:22470401

  9. Bone-repair properties of biodegradable hydroxyapatite nano-rod superstructures.

    PubMed

    D'Elía, Noelia L; Mathieu, Colleen; Hoemann, Caroline D; Laiuppa, Juan A; Santillán, Graciela E; Messina, Paula V

    2015-11-28

    Nano-hydroxyapatite (nano-HAp) materials show an analogous chemical composition to the biogenic mineral components of calcified tissues and depending on their topography they may mimic the specific arrangement of the crystals in bone. In this work, we have evaluated the potential of four synthesized nano-HAp superstructures for the in vitro conditions of bone-repair. Experiments are underway to investigate the effects of the material microstructure, surface roughness and hydrophilicity on their osseo-integration, osteo-conduction and osteo-induction abilities. Materials were tested in the presence of both, rat primary osteoblasts and rabbit mesenchymal stem cells. The following aspects are discussed: (i) cytotoxicity and material degradation; (ii) rat osteoblast spreading, proliferation and differentiation; and (iii) rabbit mesenchymal stem cell adhesion on nano-HAp and nano-HAp/collagen type I coatings. We effectively prepared a material based on biomimetic HAp nano-rods displaying the appropriate surface topography, hydrophilicity and degradation properties to induce the in vitro desired cellular responses for bone bonding and healing. Cells seeded on the selected material readily attached, proliferated and differentiated, as confirmed by cell viability, mitochondrial metabolic activity, alkaline phosphatase (ALP) activity and cytoskeletal integrity analysis by immunofluorescence localization of alpha-smooth muscle actin (α-SMA) protein. These results highlight the influence of material's surface characteristics to determine their tissue regeneration potential and their future use in engineering osteogenic scaffolds for orthopedic implants. PMID:26505580

  10. Atomistic origin of an ordered superstructure induced superconductivity in layered chalcogenides.

    PubMed

    Ang, R; Wang, Z C; Chen, C L; Tang, J; Liu, N; Liu, Y; Lu, W J; Sun, Y P; Mori, T; Ikuhara, Y

    2015-01-01

    Interplay among various collective electronic states such as charge density wave and superconductivity is of tremendous significance in low-dimensional electron systems. However, the atomistic and physical nature of the electronic structures underlying the interplay of exotic states, which is critical to clarifying its effect on remarkable properties of the electron systems, remains elusive, limiting our understanding of the superconducting mechanism. Here, we show evidence that an ordering of selenium and sulphur atoms surrounding tantalum within star-of-David clusters can boost superconductivity in a layered chalcogenide 1T-TaS2-xSex, which undergoes a superconducting transition in the nearly commensurate charge density wave phase. Advanced electron microscopy investigations reveal that such an ordered superstructure forms only in the x area, where the superconductivity manifests, and is destructible to the occurrence of the Mott metal-insulator transition. The present findings provide a novel dimension in understanding the relationship between lattice and electronic degrees of freedom. PMID:25625438

  11. Influence of plasma-treatments on the structure, superstructure, and function of membrane lipids

    NASA Astrophysics Data System (ADS)

    Hammer, Malte U.; Forbrig, Enrico; Weltmann, Klaus-Dieter; Reuter, Stephan

    2012-10-01

    Every cell, eu- or prokaryotic, has a membrane as an interface to the environment. Every substance that is applied from outside the cell has to interact with it. This includes plasma-generated reactive species in the liquid cell environment created by plasma-treatment. By the Singer and Nicolson model, proteins are embedded in a lipid bilayer. Proteins are the functional elements, lipids are the structural elements. Due to the amphiphilic nature of the lipids, they form (super-) structures in an aqueous environment. The exact superstructure is determined by a structural parameter of the lipid, its shape. Here, we show experiments on lipids by fluorophore-based liposome assays and raman spectroscopy. The results show a membrane-activity of plasma-born reactive species against lipids and lipid structures. Based on this results and literature, we propose a model for a lesion-forming mechanism in membranes of some reactive species created by plasma-treatment. It is based on a hydrophobic-hydrophilic mismatch due to lipid peroxidization induced by reactive species generated in liquids by plasma-treatment.

  12. Synthesis and electrochemical properties of biporous alpha-Fe2O3 superstructures.

    PubMed

    Amutha, Ramakrishnan; Lee, Gang-Juan; Wu, Jerry J; Sathish, Marappan; Sillanpää, Mika E T

    2013-10-01

    Biporous microsphere, flower and concaved cuboctahedrans like alpha-Fe2O3 superstructures have been synthesized by using a new synthetic method. Hydrothermal reaction of ferric chloride with potassium thiocyanate at 200 degrees C yields self-assembled microsphere, flower, and concaved cuboctahedrans like intermediates in ethanol, water:ethanol (1:1) mixed solvent and in water, respectively. These intermediates were further converted into corresponding alpha-Fe2O3 in a thermal decomposition process at 600 degrees C under oxygen atmospheric conditions. The influence of solvent, hydrothermal temperature, and concentration of iron precursors on the intermediate morphology was studied, and the growth mechanism has also been proposed. The synthesized intermediates and alpha-Fe2O3 were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM) and nitrogen adsorption analysis. The FE-SEM results indicated formation of biporous flowerlike morphology. The electrochemical properties of the flowerlike alpha-Fe2O3 electrodes in a Li-ion battery have been investigated. Plausible formation mechanisms of these intermediates were proposed. PMID:24245124

  13. Self-assembled peptide beads used as a template for ordered gold nanoparticle superstructures.

    PubMed

    de Bruyn Ouboter, Dirk; Schuster, Thomas B; Sigg, Severin J; Meier, Wolfgang P

    2013-12-01

    Using peptide-based materials to tailor self-assembled, nano-scaled hybrid materials with potentially high biocompatibility/biodegradability is gaining importance in developing a broad range of new applications, in areas such as diagnostics and medicine. Here, we investigated how the self-assembly ability of amphiphilic peptides can be used to create organized inorganic materials, i.e. gold nanoparticles. A bead-forming, purely peptidic amphiphile Ac-[K(Ac)]3-[W-l]3-W-NH2, containing acetylated (Ac) l-lysine (K), l-tryptophan (W) and d-leucine (l), was C-terminally modified with a l-cysteine (C) and linked to gold nanoparticles. Subsequent peptide-driven self-assembly of the peptide-coated gold nanoparticles with increasing water content led to controlled aggregation of the gold-core micelles, forming composite peptide-gold superstructures. The individual gold nanoparticles did not agglomerate but were separated from each other by a peptide film within the composite material, as revealed by electron microscopy studies. Structural investigation on 2D template-stripped gold demonstrated the ability of the peptides to form self-assembled monolayers. Structural elements of β-turns and weak hydrogen bonding of the hydrophobic moiety of the peptide were evident, thereby suggesting that the secondary structure remains intact. PMID:24099645

  14. Superstructures of chiral nematic microspheres as all-optical switchable distributors of light

    PubMed Central

    Aβhoff, Sarah J.; Sukas, Sertan; Yamaguchi, Tadatsugu; Hommersom, Catharina A.; Le Gac, Séverine; Katsonis, Nathalie

    2015-01-01

    Light technology is based on generating, detecting and controlling the wavelength, polarization and direction of light. Emerging applications range from electronics and telecommunication to health, defence and security. In particular, data transmission and communication technologies are currently asking for increasingly complex and fast devices, and therefore there is a growing interest in materials that can be used to transmit light and also to control the distribution of light in space and time. Here, we design chiral nematic microspheres whose shape enables them to reflect light of different wavelengths and handedness in all directions. Assembled in organized hexagonal superstructures, these microspheres of well-defined sizes communicate optically with high selectivity for the colour and chirality of light. Importantly, when the microspheres are doped with photo-responsive molecular switches, their chiroptical communication can be tuned, both gradually in wavelength and reversibly in polarization. Since the kinetics of the “on” and “off” switching can be adjusted by molecular engineering of the dopants and because the photonic cross-communication is selective with respect to the chirality of the incoming light, these photo-responsive microspheres show potential for chiroptical all-optical distributors and switches, in which wavelength, chirality and direction of the reflected light can be controlled independently and reversibly. PMID:26400584

  15. Topology and self-assembly of defect-colloidal superstructure in confined chiral nematic liquid crystals

    NASA Astrophysics Data System (ADS)

    Pandey, M. B.; Ackerman, P. J.; Burkart, A.; Porenta, T.; Žumer, S.; Smalyukh, Ivan I.

    2015-01-01

    We describe formation of defect-colloidal superstructures induced by microspheres with normal surface anchoring dispersed in chiral nematic liquid crystals in confinement-unwound homeotropic cells. Using three-dimensional nonlinear optical imaging of the director field, we demonstrate that some of the induced defects have nonsingular solitonic nature while others are singular point and line topological defects. The common director structures induced by individual microspheres have dipolar symmetry. These topological dipoles are formed by the particle and a hyperbolic point defect (or small disclination loop) of elementary hedgehog charge opposite to that of a sphere with perpendicular boundary conditions, which in cells with thickness over equilibrium cholesteric pitch ratio approaching unity are additionally interspaced by a looped double-twist cylinder of continuous director deformations. The long-range elastic interactions are probed by holographic optical tweezers and videomicroscopy, providing insights to the physical underpinnings behind self-assembled colloidal structures entangled by twisted solitons. Computer-simulated field and defect configurations induced by the colloidal particles and their assemblies, which are obtained by numerically minimizing the Landau-de Gennes free energy, are in agreement with the experimental findings.

  16. Novel superstructure of the rocksalt type and element distribution in germanium tin antimony tellurides

    NASA Astrophysics Data System (ADS)

    Rosenthal, Tobias; Welzmiller, Simon; Neudert, Lukas; Urban, Philipp; Fitch, Andy; Oeckler, Oliver

    2014-11-01

    A superstructure of the rocksalt-type observed in quenched CVT-grown single crystals of Ge3.25(7)Sn1.10(3)Sb1.10(3)Te6 was elucidated by X-ray diffraction using fourfold twinned crystals (space group P3barm1, a=4.280(1) Å, c=20.966(3) Å). The structure is built up of distorted rocksalt-type building blocks typical for long-range ordered GST materials and substitution variants thereof. In contrast to those phases, an exclusive ABC-type cubic stacking sequence of the Te-atom layers is present. High-resolution electron microscopy reveals spheroidal domains with this structure (average diameter 25 nm) whose stacking direction is perpendicular to the <1 1 1> directions of the basic rocksalt-type structure. Additional slab-like domains with a lateral extension up to 1 μm occasionally result in a hierarchical structure motif. Due to the similar electron counts of the elements involved, resonant diffraction was used in order to elucidate the element distribution in rocksalt-type building blocks of the stable layered compound 39R-Ge3SnSb2Te7 (R3barm, a=4.24990(4) Å, c=73.4677(9) Å). Sb tends to occupy the atom site close to the van der Waals gaps while Ge concentrates in the center of the building blocks.

  17. Superstructures of chiral nematic microspheres as all-optical switchable distributors of light

    NASA Astrophysics Data System (ADS)

    Aβhoff, Sarah J.; Sukas, Sertan; Yamaguchi, Tadatsugu; Hommersom, Catharina A.; Le Gac, Séverine; Katsonis, Nathalie

    2015-09-01

    Light technology is based on generating, detecting and controlling the wavelength, polarization and direction of light. Emerging applications range from electronics and telecommunication to health, defence and security. In particular, data transmission and communication technologies are currently asking for increasingly complex and fast devices, and therefore there is a growing interest in materials that can be used to transmit light and also to control the distribution of light in space and time. Here, we design chiral nematic microspheres whose shape enables them to reflect light of different wavelengths and handedness in all directions. Assembled in organized hexagonal superstructures, these microspheres of well-defined sizes communicate optically with high selectivity for the colour and chirality of light. Importantly, when the microspheres are doped with photo-responsive molecular switches, their chiroptical communication can be tuned, both gradually in wavelength and reversibly in polarization. Since the kinetics of the “on” and “off” switching can be adjusted by molecular engineering of the dopants and because the photonic cross-communication is selective with respect to the chirality of the incoming light, these photo-responsive microspheres show potential for chiroptical all-optical distributors and switches, in which wavelength, chirality and direction of the reflected light can be controlled independently and reversibly.

  18. Flip-flop logic circuit based on fully solution-processed organic thin film transistor devices with reduced variations in electrical performance

    NASA Astrophysics Data System (ADS)

    Takeda, Yasunori; Yoshimura, Yudai; Adib, Faiz Adi Ezarudin Bin; Kumaki, Daisuke; Fukuda, Kenjiro; Tokito, Shizuo

    2015-04-01

    Organic reset-set (RS) flip-flop logic circuits based on pseudo-CMOS inverters have been fabricated using full solution processing at a relatively low process temperatures of 150 °C or less. The work function for printed silver electrodes was increased from 4.7 to 5.4 eV through surface modification with a self-assembled monolayer (SAM) material. A bottom-gate, bottom-contact organic thin-film transistor (OTFT) device using a solution-processable small-molecular semiconductor material exhibited field-effect mobility of 0.40 cm2 V-1 s-1 in the saturation region and a threshold voltage (VTH) of -2.4 V in ambient air operation conditions. In order to reduce the variations in mobility and VTH, we designed a circuit with six transistors arranged in parallel, in order to average out their electrical characteristics. As a result, we have succeeded in reducing these variations without changing the absolute values of the mobility and VTH. The fabricated RS flip-flop circuits were functioned well and exhibited short delay times of 3.5 ms at a supply voltage of 20 V.

  19. Is vanadate reduced by thiols under biological conditions? Changing the redox potential of V(V)/V(IV) by complexation in aqueous solution.

    PubMed

    Crans, Debbie C; Zhang, Boyan; Gaidamauskas, Ernestas; Keramidas, Anastasios D; Willsky, Gail R; Roberts, Chris R

    2010-05-01

    Although dogma states that vanadate is readily reduced by glutathione, cysteine, and other thiols, there are several examples documenting that vanadium(V)-sulfur complexes can form and be observed. This conundrum has impacted life scientists for more than two decades. Investigation of this problem requires an understanding of both the complexes that form from vanadium(IV) and (V) and a representative thiol in aqueous solution. The reactions of vanadate and hydrated vanadyl cation with 2-mercaptoethanol have been investigated using multinuclear NMR, electron paramagnetic resonance (EPR), and UV-vis spectroscopy. Vanadate forms a stable complex of 2:2 stoichiometry with 2-mercaptoethanol at neutral and alkaline pH. In contrast, vanadate can oxidize 2-mercaptoethanol; this process is favored at low pH and high solute concentrations. The complex that forms between aqueous vanadium(IV) and 2-mercaptoethanol has a 1:2 stoichiometry and can be observed at high pH and high 2-mercaptoethanol concentration. The solution structures have been deduced based on coordination induced chemical shifts and speciation diagrams prepared. This work demonstrates that both vanadium(IV) and (V)-thiol complexes form and that redox chemistry also takes place. Whether reduction of vanadate takes place is governed by a combination of parameters: pH, solute- and vanadate-concentrations and the presence of other complexing ligands. On the basis of these results it is now possible to understand the distribution of vanadium in oxidation states (IV) and (V) in the presence of glutathione, cysteine, and other thiols and begin to evaluate the forms of the vanadium compounds that exert a particular biological effect including the insulin-enhancing agents, antiamoebic agents, and interactions with vanadium binding proteins. PMID:20359175

  20. The New Generation of Uranium In Situ Recovery Facilities: Design Improvements Should Reduce Radiological Impacts Relative to First Generation Uranium Solution Mining Plants

    SciTech Connect

    Brown, S.H.

    2008-07-01

    In the last few years, there has been a significant increase in the demand for Uranium as historical inventories have been consumed and new reactor orders are being placed. Numerous mineralized properties around the world are being evaluated for Uranium recovery and new mining / milling projects are being evaluated and developed. Ore bodies which are considered uneconomical to mine by conventional methods such as tunneling or open pits, can be candidates for non-conventional recovery techniques, involving considerably less capital expenditure. Technologies such as Uranium In Situ Leaching / In Situ Recovery (ISL / ISR - also referred to as 'solution mining'), have enabled commercial scale mining and milling of relatively small ore pockets of lower grade, and are expected to make a significant contribution to overall world wide uranium supplies over the next ten years. Commercial size solution mining production facilities have operated in the US since the mid 1970's. However, current designs are expected to result in less radiological wastes and emissions relative to these 'first' generation plants (which were designed, constructed and operated through the 1980's). These early designs typically used alkaline leach chemistries in situ including use of ammonium carbonate which resulted in groundwater restoration challenges, open to air recovery vessels and high temperature calcining systems for final product drying vs the 'zero emissions' vacuum dryers as typically used today. Improved containment, automation and instrumentation control and use of vacuum dryers in the design of current generation plants are expected to reduce production of secondary waste byproduct material, reduce Radon emissions and reduce potential for employee exposure to uranium concentrate aerosols at the back end of the milling process. In Situ Recovery in the U.S. typically involves the circulation of groundwater, fortified with oxidizing (gaseous oxygen e.g) and complexing agents (carbon

  1. Bone-repair properties of biodegradable hydroxyapatite nano-rod superstructures

    NASA Astrophysics Data System (ADS)

    D'Elía, Noelia L.; Mathieu, Colleen; Hoemann, Caroline D.; Laiuppa, Juan A.; Santillán, Graciela E.; Messina, Paula V.

    2015-11-01

    Nano-hydroxyapatite (nano-HAp) materials show an analogous chemical composition to the biogenic mineral components of calcified tissues and depending on their topography they may mimic the specific arrangement of the crystals in bone. In this work, we have evaluated the potential of four synthesized nano-HAp superstructures for the in vitro conditions of bone-repair. Experiments are underway to investigate the effects of the material microstructure, surface roughness and hydrophilicity on their osseo-integration, osteo-conduction and osteo-induction abilities. Materials were tested in the presence of both, rat primary osteoblasts and rabbit mesenchymal stem cells. The following aspects are discussed: (i) cytotoxicity and material degradation; (ii) rat osteoblast spreading, proliferation and differentiation; and (iii) rabbit mesenchymal stem cell adhesion on nano-HAp and nano-HAp/collagen type I coatings. We effectively prepared a material based on biomimetic HAp nano-rods displaying the appropriate surface topography, hydrophilicity and degradation properties to induce the in vitro desired cellular responses for bone bonding and healing. Cells seeded on the selected material readily attached, proliferated and differentiated, as confirmed by cell viability, mitochondrial metabolic activity, alkaline phosphatase (ALP) activity and cytoskeletal integrity analysis by immunofluorescence localization of alpha-smooth muscle actin (α-SMA) protein. These results highlight the influence of material's surface characteristics to determine their tissue regeneration potential and their future use in engineering osteogenic scaffolds for orthopedic implants.Nano-hydroxyapatite (nano-HAp) materials show an analogous chemical composition to the biogenic mineral components of calcified tissues and depending on their topography they may mimic the specific arrangement of the crystals in bone. In this work, we have evaluated the potential of four synthesized nano-HAp superstructures

  2. Random-type scanning patterns in laser shock peening without absorbing coating in 2024-T351 Al alloy: A solution to reduce residual stress anisotropy

    NASA Astrophysics Data System (ADS)

    Correa, C.; Peral, D.; Porro, J. A.; Díaz, M.; Ruiz de Lara, L.; García-Beltrán, A.; Ocaña, J. L.

    2015-10-01

    Laser Shock Peening (LSP) is considered as an alternative technology to shot peening (SP) for the induction of compressive residual stresses in metallic alloys in order to improve their fatigue, corrosion and wear resistance. Since laser pulses generated by high-intensity laser systems cover only a small area, laser pulses are generally overlapped and scanned in a zigzag-type pattern to cover completely the surface to be treated. However, zigzag-type scanning patterns induce residual stress anisotropy as collateral effect. The purpose of this paper is to describe and explain, for the first time and with the aid of the numerical model developed by the authors, the influence of the scanning pattern directionality on the residual stress tensor. As an effective solution, the authors propose the application of random-type scanning patterns instead of zigzag-type in order to reduce the mentioned residual stress anisotropy.

  3. Temperature-assisted On-column Solute Focusing: A General Method to Reduce Pre-column Dispersion in Capillary High Performance Liquid Chromatography

    PubMed Central

    Groskreutz, Stephen R.; Weber, Stephen G.

    2014-01-01

    Solvent-based on-column focusing is a powerful and well known approach for reducingthe impact of pre-column dispersion in liquid chromatography. Here we describe an orthogonal temperature-based approach to focusing called temperature-assisted on-column solute focusing (TASF). TASF is founded on the same principles as the more commonly used solvent-based method wherein transient conditions are created thatlead to high solute retention at the column inlet. Combining the low thermal mass of capillary columns and the temperature dependence of solute retentionTASF is used effectivelyto compress injection bands at the head of the column through the transient reduction in column temperature to 5 °C for a defined 7 mm segment of a 6 cm long 150 μm I.D. column. Following the 30 second focusing time, the column temperature is increased rapidly to the separation temperature of 60 °C releasing the focused band of analytes. We developed a model tosimulate TASF separations based on solute retention enthalpies, focusing temperature, focusing time, and column parameters. This model guides the systematic study of the influence of sample injection volume on column performance.All samples have solvent compositions matching the mobile phase. Over the 45 to 1050 nL injection volume range evaluated, TASF reducesthe peak width for all soluteswith k’ greater than or equal to 2.5, relative to controls. Peak widths resulting from injection volumes up to 1.3 times the column fluid volume with TASF are less than 5% larger than peak widths from a 45 nL injection without TASF (0.07 times the column liquid volume). The TASF approach reduced concentration detection limits by a factor of 12.5 relative to a small volume injection for low concentration samples. TASF is orthogonal to the solvent focusing method. Thus, it canbe used where on-column focusing is required, but where implementation of solvent-based focusing is difficult. PMID:24973805

  4. Superstructures and Electronic Properties of Manganese-Phthalocyanine Molecules on Au(110) from Submonolayer Coverage to Ultrathin Molecular Films.

    PubMed

    Topyła, M; Néel, N; Kröger, J

    2016-07-12

    The adsorption of manganese-phthalocyanine molecules on Au(110) was investigated using a low-temperature scanning tunneling microscope. A rich variety of commensurate superstructures was observed upon increasing the molecule coverage from submonolayers to ultrathin films. All structures were associated with reconstructions of the Au(110) substrate. Molecules adsorbed in the second molecular layer exhibited negative differential conductance occurring symmetrically around zero bias voltage. A double-barrier tunneling model rationalized this observation in terms of a peaked molecular resonance at the Fermi energy together with a voltage drop across the molecular film. PMID:27322189

  5. Orthorhombic superstructures within the rare earth strontium-doped cobaltate perovskites: Ln1-xSr xCoO 3-δ ( Ln=Y 3+, Dy 3+-Yb 3+; 0.750⩽ x⩽0.875)

    NASA Astrophysics Data System (ADS)

    James, Michael; Avdeev, Maxim; Barnes, Paris; Morales, Liliana; Wallwork, Kia; Withers, Ray

    2007-08-01

    A combination of electron, synchrotron X-ray and neutron powder diffraction reveals a new orthorhombic structure type within the Sr-doped rare earth perovskite cobaltates Ln1-xSr xCoO 3-δ ( Ln=Y 3+, Dy 3+, Ho 3+, Er 3+, Tm 3+and Yb 3+). Electron diffraction shows a C-centred cell based on a 2√2 ap×4 ap×4√2 ap superstructure of the basic perovskite unit. Not all of these very weak satellite reflections are evident in the synchrotron X-ray and neutron powder diffraction data and the average structure of each member of this series could only be refined based on Cmma symmetry and a 2√2 ap×4 ap×2√2 ap cell. The nature of structural and magnetic ordering in these phases relies on both oxygen vacancy and cation distribution. A small range of solid solution exists where this orthorhombic structure type is observed, centred roughly around the compositions Ln0.2Sr 0.8CoO 3-δ. In the case of Yb 3+ the pure orthorhombic phase was only observed for 0.850⩽ x⩽0.875. Tetragonal ( I4 /mmm; 2 ap×2 ap×4 ap) superstructures were observed for compositions having higher or lower Sr-doping levels, or for compounds with rare earth ions larger than Dy 3+. These orthorhombic phases show mixed valence (3+/4+) cobalt oxidation states between 3.2+ and 3.3+. DC magnetic susceptibility measurements show an additional magnetic transition for these orthorhombic phases compared to the associated tetragonal compounds with critical temperatures > 330 K.

  6. Key factors leading to reduced recruitment and retention of health professionals in remote areas of Ghana: a qualitative study and proposed policy solutions

    PubMed Central

    2011-01-01

    Background The ability of many countries to achieve national health goals such as the Millennium Development Goals remains hindered by inadequate and poorly distributed health personnel, including doctors. The distribution of doctors in Ghana is highly skewed, with a majority serving in two major metropolitan areas (Accra and Kumasi), and inadequate numbers in remote and rural districts. Recent policies increasing health worker salaries have reduced migration of doctors out of Ghana, but made little difference to distribution within the country. This qualitative study was undertaken to understand how practicing doctors and medical leaders in Ghana describe the key factors reducing recruitment and retention of health professionals into remote areas, and to document their proposed policy solutions. Methods In-depth interviews were carried out with 84 doctors and medical leaders, including 17 regional medical directors and deputy directors from across Ghana, and 67 doctors currently practicing in 3 regions (Greater Accra, Brong Ahafo, and Upper West); these 3 regions were chosen to represent progressively more remote distances from the capital of Accra. Results and discussion All participants felt that rural postings must have special career or monetary incentives given the loss of locum (i.e. moonlighting income), the higher workload, and professional isolation of remote assignments. Career 'death' and prolonged rural appointments were a common fear, and proposed policy solutions focused considerably on career incentives, such as guaranteed promotion or a study opportunity after some fixed term of service in a remote or hardship area. There was considerable stress placed on the need for rural doctors to have periodic contact with mentors through rural rotation of specialists, or remote learning centers, and reliable terms of appointment with fixed end-points. Also raised, but given less emphasis, were concerns about the adequacy of clinical equipment in remote

  7. One-pot synthesis of SnO{sub 2}/reduced graphene oxide nanocomposite in ionic liquid-based solution and its application for lithium ion batteries

    SciTech Connect

    Gu, Changdong Zhang, Heng; Wang, Xiuli; Tu, Jiangping

    2013-10-15

    Graphical abstract: - Highlights: • A facile and low-temperature method is developed for SnO{sub 2}/graphene composite. • Synthesis performed in a choline chloride-based ionic liquid. • The composite shows an enhanced cycling stability as anode for Li-ion batteries. • 4 nm SnO{sub 2} nanoparticles mono-dispersed on the surface of reduced graphene oxide. - Abstract: A facile and low-temperature method is developed for SnO{sub 2}/graphene composite which involves an ultrasonic-assistant oxidation–reduction reaction between Sn{sup 2+} and graphene oxide in a choline chloride–ethylene glycol based ionic liquid under ambient conditions. The reaction solution is non-corrosive and environmental-friendly. Moreover, the proposed technique does not require complicated infrastructures and heat treatment. The SnO{sub 2}/graphene composite consists of about 4 nm sized SnO{sub 2} nanoparticles with cassiterite structure mono-dispersed on the surface of reduced graphene oxide. As anode for lithium-ion batteries, the SnO{sub 2}/graphene composite shows a satisfying cycling stability (535 mAh g{sup −1} after 50 cycles @100 mA g{sup −1}), which is significantly prior to the bare 4 nm sized SnO{sub 2} nanocrsytals. The graphene sheets in the hybrid nanostructure could provide a segmentation effect to alleviate the volume expansion of the SnO{sub 2} and restrain the small and active Sn-based particles aggregating into larger and inactive clusters during cycling.

  8. Bipartite electronic superstructures in the vortex core of Bi2Sr2CaCu2O8+δ

    PubMed Central

    Machida, T.; Kohsaka, Y.; Matsuoka, K.; Iwaya, K.; Hanaguri, T.; Tamegai, T.

    2016-01-01

    The central issue in the physics of cuprate superconductivity is the mutual relationship among superconductivity, pseudogap and broken-spatial-symmetry states. A magnetic field B suppresses superconductivity, providing an opportunity to investigate the competition among these states. Although various B-induced electronic superstructures have been reported, their energy, spatial and momentum-space structures are unclear. Here, we show using spectroscopic-imaging scanning tunnelling microscopy on Bi2Sr2CaCu2O8+δ that there are two distinct B-induced electronic superstructures, both being localized in the vortex core but appearing at different energies. In the low-energy range where the nodal Bogoliubov quasiparticles are well-defined, we observe the so-called vortex checkerboard that we identify as the B-enhanced quasiparticle interference pattern. By contrast, in the high-energy region where the pseudogap develops, the broken-spatial-symmetry patterns that pre-exist at B=0 T is locally enhanced in the vortex core. This evidences the competition between superconductivity and the broken-spatial-symmetry state that is associated with the pseudogap. PMID:27230420

  9. Bipartite electronic superstructures in the vortex core of Bi2Sr2CaCu2O8+δ

    NASA Astrophysics Data System (ADS)

    Machida, T.; Kohsaka, Y.; Matsuoka, K.; Iwaya, K.; Hanaguri, T.; Tamegai, T.

    2016-05-01

    The central issue in the physics of cuprate superconductivity is the mutual relationship among superconductivity, pseudogap and broken-spatial-symmetry states. A magnetic field B suppresses superconductivity, providing an opportunity to investigate the competition among these states. Although various B-induced electronic superstructures have been reported, their energy, spatial and momentum-space structures are unclear. Here, we show using spectroscopic-imaging scanning tunnelling microscopy on Bi2Sr2CaCu2O8+δ that there are two distinct B-induced electronic superstructures, both being localized in the vortex core but appearing at different energies. In the low-energy range where the nodal Bogoliubov quasiparticles are well-defined, we observe the so-called vortex checkerboard that we identify as the B-enhanced quasiparticle interference pattern. By contrast, in the high-energy region where the pseudogap develops, the broken-spatial-symmetry patterns that pre-exist at B=0 T is locally enhanced in the vortex core. This evidences the competition between superconductivity and the broken-spatial-symmetry state that is associated with the pseudogap.

  10. Experimental Determination of Pass-By Noise Contributions from the Bogies and Superstructure of a Freight Wagon

    NASA Astrophysics Data System (ADS)

    DE BEER, F. G.; VERHEIJ, J. W.

    2000-03-01

    Pass-by noise from freight trains on straight tracks is dominated by rolling noise. The main contributions are generally accepted to originate from vibrations of the track and the wheels. However, there is uncertainty about the contributions from the bogie and the wagon superstructure. This article describes experimental methods to determine these. The methods combine vibration measurements on a rolling wagon and measurements of structural and of vibro-acoustical transfer functions under static conditions. Firstly, an inverse method is used to determine the equivalent structural excitation of a wagon. Secondly, two reciprocity methods are described for detailed vibro-acoustic transmission path analysis, with the wagon parts excited by the equivalent forces. As an example, some data will be shown from experiments on a widely used freight wagon. It appears that the contributions from two bogies and from the wagon superstructure are respectively 20 and 30dB(A) lower than the measured pass-by noise levels. Detailed information is obtained about the ranking of sub-areas which contribute to the sound radiation. The results illustrate the practical value of the methods even in the case of weak partial sources.

  11. Bipartite electronic superstructures in the vortex core of Bi2Sr2CaCu2O8+δ.

    PubMed

    Machida, T; Kohsaka, Y; Matsuoka, K; Iwaya, K; Hanaguri, T; Tamegai, T

    2016-01-01

    The central issue in the physics of cuprate superconductivity is the mutual relationship among superconductivity, pseudogap and broken-spatial-symmetry states. A magnetic field B suppresses superconductivity, providing an opportunity to investigate the competition among these states. Although various B-induced electronic superstructures have been reported, their energy, spatial and momentum-space structures are unclear. Here, we show using spectroscopic-imaging scanning tunnelling microscopy on Bi2Sr2CaCu2O8+δ that there are two distinct B-induced electronic superstructures, both being localized in the vortex core but appearing at different energies. In the low-energy range where the nodal Bogoliubov quasiparticles are well-defined, we observe the so-called vortex checkerboard that we identify as the B-enhanced quasiparticle interference pattern. By contrast, in the high-energy region where the pseudogap develops, the broken-spatial-symmetry patterns that pre-exist at B=0 T is locally enhanced in the vortex core. This evidences the competition between superconductivity and the broken-spatial-symmetry state that is associated with the pseudogap. PMID:27230420

  12. Inclusion of cut and as-grown single-walled carbon nanotubes in the helical superstructure of schizophyllan and curdlan (beta-1,3-glucans).

    PubMed

    Numata, Munenori; Asai, Masayoshi; Kaneko, Kenji; Bae, Ah-Hyun; Hasegawa, Teruaki; Sakurai, Kazuo; Shinkai, Seiji

    2005-04-27

    We have found that single-chain schizophyllan and curdlan (s-SPG and s-curdlan, respectively) can dissolve as-grown and cut single-walled carbon nanotubes (ag-SWNTs and c-SWNTs, respectively) in aqueous solution. The vis-NIR spectra of the composites suggest that c-SWNTs are dissolved as a bundle, whereas ag-SWNTs exist as one or only a few pieces in the tubular hollow constructed by the helical structure inherent to these beta-1,3-glucans. EDX and CLSM measurements and TEM observation established that the distribution map of these polysaccharides overlaps well with the image of SWNTs, indicating that these two components form a composite. Very interestingly, when c-SWNTs were dissolved with the aid of s-SPG or s-curdlan in water, a clear periodical structure with inclined stripes, as detected by AFM, appeared on the fibrous composite surface. Because this periodical structure has never been recognized for the composites with other water-soluble polymers, one can regard that s-SPG or s-curdlan wraps c-SWNTs constructing a helically twined structure. High-resolution TEM observation of an ag-SWNTs/s-SPG composite gave a clearer image in that two s-SPG chains twine one ag-SWNT and the helical motif is right-handed. When this sample was subjected to the AFM measurement, the composite showed the 2-3 nm height. This height implies that one piece of ag-SWNT is included in the s-SPGs helical structure. As a summary, it has been established that beta-1,3-glucans such as s-SPG and s-curdlan not only dissolve SWNTs but also create a novel superstructure on the surface. PMID:15839686

  13. Totally solution-processed CuInS2 solar cells based on chloride inks: reduced metastable phases and improved current density

    NASA Astrophysics Data System (ADS)

    Dehghani, Mehdi; Behjat, Abbas; Tajabadi, Fariba; Taghavinia, Nima

    2015-03-01

    Planar superstrate CuInS2 (CIS) solar cell devices are fabricated using totally solution-processed deposition methods. These Cd-free devices are structured by FTO/TiO2/In2S3/CIS/carbon, where TiO2 and In2S3 are deposited by spray pyrolysis, and a CIS film is deposited using spin-coating followed by annealing at 250 °C. The pasted carbon layer is utilized as the anode. No further sulfurization or selenization is employed. The Cu/In ratio in the ink is found as a critical factor affecting the morphology and crystallinity of the film as well as the photovoltaic performance of the device. An optimum Cu/In = 1.05 results in large-grain films with sharp diffraction peaks and, subsequently, optimal series resistance and shunt conductance. It is also found that the chloride-based ink results in CIS films with considerably reduced metastable phases, compared to the conventional acetate-based inks. A current density of 23.6 mA cm-2 is obtained for the best devices, leading to a conversion efficiency of 4.1%.

  14. Modification of the mean near-wall velocity profile of a high-Reynolds number turbulent boundary layer with the injection of drag-reducing polymer solutions

    NASA Astrophysics Data System (ADS)

    Elbing, Brian R.; Perlin, Marc; Dowling, David R.; Ceccio, Steven L.

    2013-08-01

    The current study explores the influence of polymer drag reduction on the near-wall velocity distribution in a turbulent boundary layer (TBL) and its dependence on Reynolds number. Recent moderate Reynolds number direct numerical simulation and experimental studies presented in White et al. [Phys. Fluids 24, 021701 (2012)], 10.1063/1.3681862 have challenged the classical representation of the logarithmic dependence of the velocity profile for drag-reduced flows, especially at drag reduction levels above 40%. In the present study, high Reynolds number data from a drag reduced TBL is presented and compared to the observations of White et al. [Phys. Fluids 24, 021701 (2012)], 10.1063/1.3681862. Data presented here were acquired in the TBL flow on a 12.9-m-long flat plate at speeds to 20.3 m s-1, achieving momentum thickness based Reynolds number to 1.5 × 105, which is an order of magnitude greater than that available in the literature. Polyethylene oxide solutions with an average molecular weight of 3.9 × 106 g mol-1 were injected into the flow at various concentrations and volumetric fluxes to achieve a particular level of drag reduction. The resulting mean near-wall velocity profiles show distinctly different behavior depending on whether they fall in the low drag reduction (LDR) or the high drag reduction (HDR) regimes, which are nominally divided at 40% drag reduction. In the LDR regime, the classical view that the logarithmic slope remains constant at the Newtonian value and the intercept constant increases with increasing drag reduction appears to be valid. However, in the HDR regime the behavior is no longer universal. The intercept constant continues to increase linearly in proportion to the drag reduction level until a Reynolds-number-dependent threshold is achieved, at which point the intercept constant rapidly decreases to that predicted by the ultimate profile. The rapid decrease in the intercept constant is due to the corresponding increase in the

  15. Pr{sub 1.33}Pt{sub 4}Ga{sub 10}: Superstructure and magnetism

    SciTech Connect

    Doan Nguyen, Sau; Ryan, Kevin; Chai, Ping; Shatruk, Michael; Xin, Yan; Chapman, Karena W.; Chupas, Peter J.; Fronczek, Frank R.; Macaluso, Robin T.

    2014-12-15

    Pr{sub 1.33}Pt{sub 4}Ga{sub 10} crystals were prepared by Ga-flux method. The superstructure of this compound was studied by single-crystal X-ray diffraction (XRD), transmission electron microscopy (TEM), and diffuse X-ray scattering. Pr{sub 1.33}Pt{sub 4}Ga{sub 10} adopts the P6{sub 3}/mmc space group with a=b=4.3227(5) Å, c=16.485(3) Å: the structure features Pr{sub 2}Ga{sub 3} layers alternating with Pt{sub 2}Ga{sub 4} layers along the c-axis. TEM studies and pair distribution function (PDF) analysis of X-ray total scattering data show that Pr{sub 2}Ga{sub 3} layers possess an ordered superstructure (of dimension a′=a√(3)) in which Pr vacancies and Ga atoms are ordered within the ab-plane but disordered along the c-direction. PDF analysis also shows temperature-dependent structural features local to the Pr{sup 3+} ion. Magnetic measurements reveal that Pr{sup 3+} ions order ferrimagnetically below 12.5(2) K. - Graphical abstract: Left: Crystal structure of Pr{sub 1.33}Pt{sub 4}Ga{sub 10} showing Pr and Ga vacancies in the Pr{sub 2}Ga{sub 3} plane. Right: Tunneling electron microscopy (TEM) image of Pr{sub 1.33}Pt{sub 4}Ga{sub 10}. These vacancies have been studied using TEM and pair distribution function analysis. Magnetic measurements reveal that Pr{sup 3+} ions order ferrimagnetically below 7.8(2) K. - Highlights: • TEM studies indicate a superstructure from Pr and Ga vacancies. • Pair distribution function analyses may point to structural relaxation of vacancies. • Pr{sub 1.33}Pt{sub 4}Ga{sub 10} behaves as a ferromagnet and exhibits a metamagnetic transition.

  16. Ultrasensitive SERS detection of VEGF based on a self-assembled Ag ornamented-AU pyramid superstructure.

    PubMed

    Zhao, Sen; Ma, Wei; Xu, Liguang; Wu, Xiaoling; Kuang, Hua; Wang, Libing; Xu, Chuanlai

    2015-06-15

    For the first time, we demonstrated the fabrication of silver nanoparticle ornamented-gold nanoparticle pyramids (Ag-Au Pys) using an aptamer-based self-assembly process and investigated their surface-enhanced Raman scattering (SERS) properties in the detection of vascular endothelial growth factor (VEGF). Under optimized conditions, the SERS signal was negatively related to VEGF concentration over the range 0.01-1.0 fM and the limit of detection (LOD) was as low as 22.6 aM. The matrix effect and the specificity of this developed method were further examined, and the results showed that the superstructure sensor was ultrasensitive and highly selective. This developed aptamer-based SERS detection method suggests that it may be a promising strategy for a variety of sensing applications. PMID:25643599

  17. An amplified electrochemical strategy using DNA-QDs dendrimer superstructure for the detection of thymine DNA glycosylase activity.

    PubMed

    Liu, Hongying; Lou, Youbing; Zhou, Fei; Zhu, Hao; Abdel-Halim, E S; Zhu, Jun-Jie

    2015-09-15

    A triple-signal amplification strategy was proposed for highly sensitive and selective detection of thymine DNA glycosylase (TDG) by coupling a dendrimer-like DNA label with the electrochemical method and quantum dots (QDs) tagging. The DNA-QDs dendrimer-like superstructure was designed by DNA hybridization and covalent assembling. Benefiting from outstanding performance of the amplification strategy, this assay showed high sensitivity, extraordinary stability, and easy operation. The limit of detection could reach 0.00003 U µL(-1) with a splendid specificity. The TDG content in different concentration of HeLa cell was also determined. This assay opens a new horizon for both qualitative and quantitative detection of TDG, holding great promise for potential application in cancer cell research and clinical diagnostics. PMID:25913445

  18. Superstructure of hollandite K xMg (8+x)/3Sb (16-x)/3O 16 ( x≈1.76)

    NASA Astrophysics Data System (ADS)

    Michiue, Yuichi

    2007-06-01

    Single crystals of K xMg (8+x)/3Sb (16-x)/3O 16 ( x≈1.76) with a hollandite superstructure were grown. Ordering schemes for guest ions (K) and the host structure were confirmed by the structure refinement using X-ray diffraction intensities. The space group is I4/ m and cell parameters are a=10.3256(6), c=9.2526(17)Å with Z=3. Superlattice formation is primarily attributed to the Mg/Sb occupational modulation in the host structure. Mg/Sb ratios at two nonequivalent metal sites are 0.8977/0.1023 and 0.1612/0.8388. Two types of the cavity are seen in the tunnel, where parts of K ions deviate from the cavity center along the tunnel direction. Probability densities for K ions in the two cavities are different from each other, which seems to have arisen from the Mg/Sb modulation.

  19. Small-Angle X-ray Scattering Study of Intramuscular Fish Bone: Collagen Fibril Superstructure Determined from Equidistant Meridional Reflections

    SciTech Connect

    Burger,C.; Zhou, H.; Sics, I.; Hsiao, B.; Chu, B.; Graham, L.; Glimcher, M.

    2008-01-01

    New insights into the bone collagen fibril superstructure have been obtained by novel small-angle X-ray scattering analysis. The analysis was carried out on the small-angle equidistant meridional reflections resulting from the periodic structure of collagen fibrils in their axial direction. Conventional two-dimensional analysis is difficult because of the large discrepancy of longitudinal and lateral length scales for individual fibrils, as well as their preferred orientation. The new approach represents an unapproximated analysis of the equidistant meridional reflections, which takes the exact separation of preferred orientation and fibril size effects into account. The analytical results (e.g. axial period, fibril diameter etc.) agree well with the parameters obtained from transmission electron microscopy.

  20. Magnetic Superstructure and Metal-Insulator Transition in Mn-Substituted Sr3Ru2O7

    NASA Astrophysics Data System (ADS)

    Hossain, M. A.; Bohnenbuck, B.; Chuang, Y.-D.; Geck, J.; Tokura, Y.; Yoshida, Y.; Hussain, Z.; Keimer, B.; Sawatzky, G. A.; Damascelli, A.

    2010-03-01

    We present a temperature-dependent resonant elastic soft x-ray scattering (REXS) study of the metal-insulator transition in Sr3(Ru1-xMnx)2O7, performed at both Ru and Mn L-edges. Resonant magnetic superstructure reflections, which indicate an incipient instability of the parent compound, are detected below the transition. Based on modelling of the REXS intensity from randomly distributed Mn impurities, we establish the inhomogeneous nature of the metal-insulator transition, with an effective percolation threshold corresponding to an anomalously low x˜0.05 Mn substitution. In collaboration with A.G. Cruz Gonzalez, J.D. Denlinger (Berkeley Lab), I. Zegkinoglou, M.W. Haverkort (MPI, Stuttgart), I.S. Elfimov, D.G. Hawthorn (UBC), R. Mathieu, S. Satow, H. Takagi (Tokyo), H.-H. Wu and C. Sch"ußler-Langeheine (Cologne).

  1. Engineered Solutions to Reduce Occupational Noise Exposure at the NASA Glenn Research Center: A Five-Year Progress Summary (1994-1999)

    NASA Technical Reports Server (NTRS)

    Cooper, Beth A.; Hange, Donald W.; Mikulic, John J.

    1999-01-01

    to reducing occupational and community noise exposure. The organization and mission of this Program were documented shortly after its inception, and individual programmatic components have been the subject of subsequent papers. This paper summarizes the status and accomplishments of the engineering aspects of the Program from a five-year retrospective viewpoint and includes a review of retrofit noise control solution strategies, which have not been previously documented.

  2. The Influence of Impurities in a Water Solution with Drag Reducing Surfactants on the Flow Drag-Reduction and a Recovering Method of Its Decreased Drag Reduction Effect.

    NASA Astrophysics Data System (ADS)

    Nakata, Toru; Sato, Kenji; Inaba, Hideo; Horibe, Akihiko; Haruki, Naoto

    The drag reduction of a water flow with new drag reducing surfactants (amine oxide type nonionic surfactants, mixtures of amine oxide type nonionic surfactants and betaine type amphoteric surfactants) which were selected as environmentally acceptable drag reducing additives was investigated experimentally. Addition of amine oxide type nonionic surfactants to hot or cold water can reduce flow drag in a turbulent pipe flow. The present research investigated how various ionic components dissolved in water affected this drag reducing effect. It was found that ionic impurities contained in the water affected the pipe flow drag reducing effect by amine oxide type nonionic surfactants. Moreover, it was clarified that the decrease in the pipe flow drag reducing effect was recovered by adding a mixture of amine oxide type nonionic surfactants and betaine type amphoteric surfactant to the water with ionic impurities.

  3. Hierarchical super-structure identified by polarized light microscopy, electron microscopy and nanoindentation: Implications for the limits of biological control over the growth mode of abalone sea shells

    PubMed Central

    2012-01-01

    Background Mollusc shells are commonly investigated using high-resolution imaging techniques based on cryo-fixation. Less detailed information is available regarding the light-optical properties. Sea shells of Haliotis pulcherina were embedded for polishing in defined orientations in order to investigate the interface between prismatic calcite and nacreous aragonite by standard materialographic methods. A polished thin section of the interface was prepared with a defined thickness of 60 μm for quantitative birefringence analysis using polarized light and LC-PolScope microscopy. Scanning electron microscopy images were obtained for comparison. In order to study structural-mechanical relationships, nanoindentation experiments were performed. Results Incident light microscopy revealed a super-structure in semi-transparent regions of the polished cross-section under a defined angle. This super-structure is not visible in transmitted birefringence analysis due to the blurred polarization of small nacre platelets and numerous organic interfaces. The relative orientation and homogeneity of calcite prisms was directly identified, some of them with their optical axes exactly normal to the imaging plane. Co-oriented "prism colonies" were identified by polarized light analyses. The nacreous super-structure was also visualized by secondary electron imaging under defined angles. The domains of the super-structure were interpreted to consist of crystallographically aligned platelet stacks. Nanoindentation experiments showed that mechanical properties changed with the same periodicity as the domain size. Conclusions In this study, we have demonstrated that insights into the growth mechanisms of nacre can be obtained by conventional light-optical methods. For example, we observed super-structures formed by co-oriented nacre platelets as previously identified using X-ray Photo-electron Emission Microscopy (X-PEEM) [Gilbert et al., Journal of the American Chemical Society 2008, 130

  4. Surface superstructures of quasi-one-dimensional organic conductor β-(BEDT-TTF)2PF6 crystal studied by scanning tunneling microscopy

    NASA Astrophysics Data System (ADS)

    Shigekawa, H.; Miyake, K.; Miyauchi, A.; Ishida, M.; Oigawa, H.; Nannichi, Y.; Yoshizaki, R.; Mori, T.

    1995-12-01

    Two kinds of superstructures were found at ~280 K by scanning tunneling microscopy on the crystal surface of β-(BEDT-TFF)2PF6, a quasi-one-dimensional organic conductor with a metal-insulator phase transition at ~297 K. One has a structural modulation which is perpendicular to the one-dimensional conductive axis, similar to that previously observed on a TTF-TCNQ crystal surface. The other has a twofold periodicity along the one-dimensional conductive axis, as expected from the theory. Under the assumption that the former is an intermediate structure caused by the interaction between neighboring one-dimensional molecular chains, superstructures which have been observed in BEDT-TTF compounds could be explained well.

  5. Long-range two-dimensional superstructure in the superconducting electron-doped cuprate Pr0.88LaCe0.12CuO4

    NASA Astrophysics Data System (ADS)

    Campbell, B. J.; Rosenkranz, S.; Kang, H. J.; Stokes, H. T.; Chupas, P. J.; Komiya, S.; Ando, Y.; Li, Shiliang; Dai, Pengcheng

    2015-07-01

    Utilizing single-crystal synchrotron x-ray scattering, we observe distorted CuO2 planes in the electron-doped superconductor Pr1 -xLaCexCuO4 +δ , x = 0.12. Resolution-limited rods of scattering are indicative of a long-range two-dimensional 2 √{2 }×2 √{2 } superstructure in the a -b plane, adhering to planar space-group symmetry p 4 g m , which is subject to stacking disorder perpendicular to the planes. This superstructure is present only in annealed, superconducting samples, but not in the as-grown, nonsuperconducting samples. These long-range distortions of the CuO2 planes, which are generally considered to be detrimental to superconductivity, have avoided detection to date due to the challenges of observing and interpreting subtle diffuse-scattering features.

  6. Simultaneous phase and shape control of monodisperse NaLuF4:Yb, Er microcrystals and greatly enhanced upconversion luminescence from their superstructures

    NASA Astrophysics Data System (ADS)

    Li, Wenbin; Tan, Congbing; Zhang, Yutao

    2013-05-01

    Simultaneous phase- and shape-controlled NaLuF4 microcrystals co-doped with Yb3+/Er3+ have been synthesized via a facile hydrothermal method by only changing the precursor pH value. The UC emission efficiency of these obtained microparticles showed a strong phase- and shape-dependency. Under irradiation of 980 nm, the luminescence intensity of hexagonal NaLuF4 microcrystals presents an enhancement by at least 5.8 times relative to their cubic counterpart. Specially, an up to 168-fold enhancement of emission intensity from the NaLuF4 superstructures, compared with the microplates with identical hexagonal phase, was observed. Such improvement is likely to be dominated by the laser-cavity mirrors effect from the microcavities on their surface of the NaLuF4 superstructures. These results will permit a promising step to harness the upconversion phosphors in solid state lasers.

  7. A stable single-crystal Bi3NbO7 nanoplates superstructure for effective visible-light-driven photocatalytic removal of nitric oxide

    NASA Astrophysics Data System (ADS)

    Ai, Zhihui; Ho, Wingkei; Lee, Shuncheng

    2012-12-01

    In this study, bismuth niobate (Bi3NbO7) single-crystal nanoplates superstructure (BNS) was prepared via a facile hydrothermal route without adding any surfactants and templates by using bismuth citric and niobium pentoxide as precursors. The as-prepared products were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) nitrogen adsorption-desorption, X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectrum (DRS). The characterization results revealed that the BNS nanostructures were self-assembled of single crystalline nanoplates under hydrothermal environment. These BNS exhibited excellent visible-light-driven (λ > 420 nm) photocatalytic performances for the removal of gaseous nitrogen monoxide (NO), the removal of NO reached 42.3% in 40 min at the presence of BNS, which was much higher than those of C-doped TiO2 (25% of NO removal), the InVO4 hollow microspheres (25% of NO removal), as well as the BiOBr nanoplates microspheres (30% of NO removal). Close investigation indicated that plenty of pores existed in the aggregation of BNS superstructures, which could serve as efficient transport paths for NO molecules and harvesting of more light. Moreover, the BNS exhibited high stability during multiple runs of photocatalytic removal of NO due to their special superstructures. The study provides a facile method to synthesize BNS with high efficiency and high stability in the visible-light spectral range.

  8. Novel symmetrical coralloid Cu 3D superstructures: Solid-state synthesis from a Cu-carboxylate MOF and their in-situ thermal conversion

    SciTech Connect

    Chen Lingyun; Shen Yongming; Bai Junfeng; Wang Chunzhao

    2009-08-15

    We describe here a one-step solid-state process for the synthesis of metal three-dimensional (3D) superstructures from a metal-organic framework (MOF). Novel symmetrical coralloid Cu 3D superstructures with surface interspersed with clusters of Cu nanoparticles were successfully synthesized by thermolysis of the [Cu{sub 3}(btc){sub 2}] (btc=benzene-1,3,5-tricarboxylato) MOF in a one-end closed horizontal tube furnace (OCTF). The obtained products were characterized by TGA, FT-IR, XRD, EDX, SEM, TEM, HRTEM and SAED. Different reaction conditions were discussed. Furthermore, the synthesized Cu samples were converted into CuO microstructures by in-situ calcination in the air. In addition, the possible formation mechanism was also proposed. This method is a simple and facile route, which builds a direct linkage between metal-carboxylate MOF crystals and metal nano- or microstructures and also opens a new application field of MOFs. - Graphical abstract: Novel symmetrical coralloid Cu 3D superstructures were synthesized by thermolysis of the [Cu{sub 3}(btc){sub 2}] (btc=benzene-1,3,5-tricarboxylato) MOF microcrystals in a one-end closed horizontal tube furnace (OCTF).

  9. Spatial Separation of Charge Carriers in In2O3-x(OH)y Nanocrystal Superstructures for Enhanced Gas-Phase Photocatalytic Activity.

    PubMed

    He, Le; Wood, Thomas E; Wu, Bo; Dong, Yuchan; Hoch, Laura B; Reyes, Laura M; Wang, Di; Kübel, Christian; Qian, Chenxi; Jia, Jia; Liao, Kristine; O'Brien, Paul G; Sandhel, Amit; Loh, Joel Y Y; Szymanski, Paul; Kherani, Nazir P; Sum, Tze Chien; Mims, Charles A; Ozin, Geoffrey A

    2016-05-24

    The development of strategies for increasing the lifetime of photoexcited charge carriers in nanostructured metal oxide semiconductors is important for enhancing their photocatalytic activity. Intensive efforts have been made in tailoring the properties of the nanostructured photocatalysts through different ways, mainly including band-structure engineering, doping, catalyst-support interaction, and loading cocatalysts. In liquid-phase photocatalytic dye degradation and water splitting, it was recently found that nanocrystal superstructure based semiconductors exhibited improved spatial separation of photoexcited charge carriers and enhanced photocatalytic performance. Nevertheless, it remains unknown whether this strategy is applicable in gas-phase photocatalysis. Using porous indium oxide nanorods in catalyzing the reverse water-gas shift reaction as a model system, we demonstrate here that assembling semiconductor nanocrystals into superstructures can also promote gas-phase photocatalytic processes. Transient absorption studies prove that the improved activity is a result of prolonged photoexcited charge carrier lifetimes due to the charge transfer within the nanocrystal network comprising the nanorods. Our study reveals that the spatial charge separation within the nanocrystal networks could also benefit gas-phase photocatalysis and sheds light on the design principles of efficient nanocrystal superstructure based photocatalysts. PMID:27159793

  10. Selected-control solution-phase route to multiple-dendritic and cuboidal structures of PbSe

    SciTech Connect

    Li Benxia; Xie Yi . E-mail: yxielab@ustc.edu.cn; Xu Yang; Wu Changzheng; Li Zhengquan

    2006-01-15

    Well-crystalline PbSe multiple-dendritic hierarchical structures have been prepared through a facile hydrothermal process in an alkaline glycerol/water solution system using SeO{sub 2} as selenium source and hydrous hydrazine as reducing agent at 160 deg. C for 12 h. The obtained products were characterized by X-ray powder diffraction, field emission scanning electron microscopy and transmission electron microscopy, which showed that the obtained products were face-centered cubic PbSe multiple-dendritic superstructures with length of each dendrite ranging from 1.0 to 1.5 {mu}m. Additionally, cuboidal PbSe microcrystals with different concave faces can be obtained through a similar process except for using Se powders instead of SeO{sub 2} as selenium source and without hydrous hydrazine. The edge lengths of these cuboidal microcrystals range from 1.0 to 2.5 {mu}m observed by field emission scanning electron microscopy. The influencing factors for the formation of the two kinds of PbSe microstructures were discussed and the possible growth mechanisms were proposed from the point of crystallographic and kinetic views. The studies on the corresponding photoluminescence (PL) properties of the two kinds of PbSe structures are also carried out. -- Graphical abstract: PbSe multiple-dendritic hierarchical structure with 4-fold structural symmetry and cuboidal microcrystals with concave faces were selectively obtained by using different selenium sources in a glycerol/water solution system.

  11. Using Finite Element and Eigenmode Expansion Methods to Investigate the Periodic and Spectral Characteristic of Superstructure Fiber Bragg Gratings

    PubMed Central

    He, Yue-Jing; Hung, Wei-Chih; Lai, Zhe-Ping

    2016-01-01

    In this study, a numerical simulation method was employed to investigate and analyze superstructure fiber Bragg gratings (SFBGs) with five duty cycles (50%, 33.33%, 14.28%, 12.5%, and 10%). This study focuses on demonstrating the relevance between design period and spectral characteristics of SFBGs (in the form of graphics) for SFBGs of all duty cycles. Compared with complicated and hard-to-learn conventional coupled-mode theory, the result of the present study may assist beginner and expert designers in understanding the basic application aspects, optical characteristics, and design techniques of SFBGs, thereby indirectly lowering the physical concepts and mathematical skills required for entering the design field. To effectively improve the accuracy of overall computational performance and numerical calculations and to shorten the gap between simulation results and actual production, this study integrated a perfectly matched layer (PML), perfectly reflecting boundary (PRB), object meshing method (OMM), and boundary meshing method (BMM) into the finite element method (FEM) and eigenmode expansion method (EEM). The integrated method enables designers to easily and flexibly design optical fiber communication systems that conform to the specific spectral characteristic by using the simulation data in this paper, which includes bandwidth, number of channels, and band gap size. PMID:26861322

  12. Using Finite Element and Eigenmode Expansion Methods to Investigate the Periodic and Spectral Characteristic of Superstructure Fiber Bragg Gratings.

    PubMed

    He, Yue-Jing; Hung, Wei-Chih; Lai, Zhe-Ping

    2016-01-01

    In this study, a numerical simulation method was employed to investigate and analyze superstructure fiber Bragg gratings (SFBGs) with five duty cycles (50%, 33.33%, 14.28%, 12.5%, and 10%). This study focuses on demonstrating the relevance between design period and spectral characteristics of SFBGs (in the form of graphics) for SFBGs of all duty cycles. Compared with complicated and hard-to-learn conventional coupled-mode theory, the result of the present study may assist beginner and expert designers in understanding the basic application aspects, optical characteristics, and design techniques of SFBGs, thereby indirectly lowering the physical concepts and mathematical skills required for entering the design field. To effectively improve the accuracy of overall computational performance and numerical calculations and to shorten the gap between simulation results and actual production, this study integrated a perfectly matched layer (PML), perfectly reflecting boundary (PRB), object meshing method (OMM), and boundary meshing method (BMM) into the finite element method (FEM) and eigenmode expansion method (EEM). The integrated method enables designers to easily and flexibly design optical fiber communication systems that conform to the specific spectral characteristic by using the simulation data in this paper, which includes bandwidth, number of channels, and band gap size. PMID:26861322

  13. Magnetic Superstructure and Metal-Insulator Transition in Mn-Substituted Sr3 Ru 2 O 7

    NASA Astrophysics Data System (ADS)

    Hossain, M. A.; Zhu, Z. H.; Bohnenbuck, B.; Chuang, Y.-D.; Yoshida, Y.; Hussain, Z.; Keimer, B.; Elfimov, I. S.; Sawatzky, G. A.; Damascelli, A.

    2011-03-01

    We present a temperature-dependent resonant elastic soft x-ray scattering (REXS) study of the metal-insulator transition in Sr 3 (Ru 1-x Mn x)2 O7 , performed at both Ru and Mn L -edges. Resonant magnetic superstructure reflections together with ab-initio density functional theory calculations identify the ground state as a spin checkerboard with blocks of 4 spins up and 4 spins down. Based on modelling of the REXS intensity from randomly distributed Mn impurities, we establish the inhomogeneous nature of the metal-insulator transition, with an effective percolation threshold corresponding to an anomalously low x ~ 0.05 Mn substitution. Perhaps more important, our results suggest that the same checkerboard instability might be present already in the parent compound Sr 3 Ru 2 O7 . In collaboration with: A.G. Cruz Gonzalez, J.D. Denlinger (Berkeley) I. Zegkinoglou, M.W. Haverkort (MPI) J. Geck, D.G. Hawthorn (UBC) R. Mathieu, Y. Tokura, S. Satow, H. Takagi (Tokyo) H.-H. Wu and C. Schussler-Langeheine (Cologne).

  14. Pyrroloquinoline quinone (PQQ) is reduced to pyrroloquinoline quinol (PQQH2) by vitamin C, and PQQH2 produced is recycled to PQQ by air oxidation in buffer solution at pH 7.4.

    PubMed

    Mukai, Kazuo; Ouchi, Aya; Nagaoka, Shin-ichi; Nakano, Masahiko; Ikemoto, Kazuto

    2015-01-01

    Measurements of the reaction of sodium salt of pyrroloquinoline quinone (PQQNa2) with vitamin C (Vit C) were performed in phosphate-buffered solution (pH 7.4) at 25 °C under nitrogen atmosphere, using UV-vis spectrophotometry. The absorption spectrum of PQQNa2 decreased in intensity due to the reaction with Vit C and was changed to that of pyrroloquinoline quinol (PQQH2, a reduced form of PQQ). One molecule of PQQ was reduced by two molecules of Vit C producing a molecule of PQQH2 in the buffer solution. PQQH2, thus produced, was recycled to PQQ due to air oxidation. PQQ and Vit C coexist in many biological systems, such as vegetables, fruits, as well as in human tissues. The results obtained suggest that PQQ is reduced by Vit C and functions as an antioxidant in biological systems, because it has been reported that PQQH2 shows very high free-radical scavenging and singlet-oxygen quenching activities in buffer solutions. PMID:26264520

  15. Communication: A reduced-space algorithm for the solution of the complex linear response equations used in coupled cluster damped response theory

    NASA Astrophysics Data System (ADS)

    Kauczor, Joanna; Norman, Patrick; Christiansen, Ove; Coriani, Sonia

    2013-12-01

    We present a reduced-space algorithm for solving the complex (damped) linear response equations required to compute the complex linear response function for the hierarchy of methods: coupled cluster singles, coupled cluster singles and iterative approximate doubles, and coupled cluster singles and doubles. The solver is the keystone element for the development of damped coupled cluster response methods for linear and nonlinear effects in resonant frequency regions.

  16. Final Technical Report HFC Concrete: A Low­Energy, Carbon-Dioxide­Negative Solution for reducing Industrial Greenhouse Gas Emissions

    SciTech Connect

    Dr. Larry McCandlish, Principal Investigator; Dr. Richard Riman, Co-Principal Investigator

    2012-05-14

    Solidia/CCSM received funding for further research and development of its Low Temperature Solidification Process (LTS), which is used to create hydrate-free concrete (HFC). LTS/HFC is a technology/materials platform that offers wide applicability in the built infrastructure. Most importantly, it provides a means of making concrete without Portland cement. Cement and concrete production is a major consumer of energy and source of industrial greenhouse gas (GHG) emissions. The primary goal of this project was to develop and commercialize a novel material, HFC, which by replacing traditional concrete and cement, reduces both energy use and GHG emissions in the built infrastructure. Traditional concrete uses Portland Cement (PC) as a binder. PC production involves calcination of limestone at {approx}1450 C, which releases significant amounts of CO{sub 2} gas to the atmosphere and consumes a large amount of energy due to the high temperature required. In contrast, HFC is a carbonate-based hydrate-free concrete (HFC) that consumes CO{sub 2} gas in its production. HFC is made by reaction of silicate minerals with CO{sub 2} at temperatures below 100 C, more than an order-of-magnitude below the temperature required to make PC. Because of this significant difference in temperature, it is estimated that we will be able to reduce energy use in the cement and concrete industry by up to 30 trillion Btu by 2020. Because of the insulating properties of HFC, we believe we will also be able to significantly reduce energy use in the Building sector, though the extent of this saving is not yet quantified. It is estimated that production of a tonne of PC-based concrete requires about 6.2 million Btu of energy and produces over 1 tonne of CO{sub 2} emissions (Choate, 2003). These can be reduced to 1.9 million Btu and 0.025 tonnes of CO{sub 2} emissions per tonne of HFC (with overall CO{sub 2}-negativity possible by increasing carbonation yield). In this way, by replacing PC

  17. Green synthesis and antibacterial effects of aqueous colloidal solutions of silver nanoparticles using camomile terpenoids as a combined reducing and capping agent.

    PubMed

    Parlinska-Wojtan, Magdalena; Kus-Liskiewicz, Małgorzata; Depciuch, Joanna; Sadik, Omowunmi

    2016-08-01

    Green synthesis method using camomile extract was applied to synthesize silver nanoparticles to tune their antibacterial properties merging the synergistic effect of camomile and Ag. Scanning transmission electron microscopy revealed that camomile extract (CE) consisted of porous globular nanometer sized structures, which were a perfect support for Ag nanoparticles. The Ag nanoparticles synthesized with the camomile extract (AgNPs/CE) of 7 nm average sizes, were uniformly distributed on the CE support, contrary to the pure Ag nanoparticles synthesized with glucose (AgNPs/G), which were over 50 nm in diameter and strongly agglomerated. The energy dispersive X-ray spectroscopy chemical analysis showed that camomile terpenoids act as a capping and reducing agent being adsorbed on the surface of AgNPs/CE enabling their reduction from Ag(+) and preventing them from agglomeration. Fourier transform infrared and ultraviolet-visible spectroscopy measurements confirmed these findings, as the spectra of AgNPs/CE, compared to pure CE, did not contain the 1109 cm(-1) band, corresponding to -C-O groups of terpenoids and the peaks at 280 and 320 nm, respectively. Antibacterial tests using four bacteria strains showed that the AgNPs/CE performed five times better compared to CE AgNPs/G samples, reducing totally all the bacteria in 2 h. PMID:27083587

  18. Boost the electron mobility of solution-grown organic single crystals via reducing the amount of polar solvent residues

    SciTech Connect

    Xue, Guobiao; Xin, Huolin L.; Wu, Jiake; Fan, Congcheng; Liu, Shuang; Huang, Zhuoting; Liu, Yujing; Shan, Bowen; Miao, Qian; Chen, Hongzheng; Li, Hanying

    2015-10-29

    Enhancing electron transport to match with the development in hole transport is critical for organic electronics in the future. As electron motion is susceptible to extrinsic factors, seeking these factors and avoiding their negative effects have become the central challenge. Here, the existence of polar solvent residues in solution-grown single-crystals of 6,13-bis(triisopropylsilylethynyl)-5,7,12,14-tetraazapentacene is identified as a factor detrimental to electron motion. Field-effect transistors of the crystals exhibit electron mobility boosted by about 60% after the residues are removed. The average electron mobility reaches up to 8.0 ± 2.2 cm2 V–1 s–1 with a highest value of 13.3 cm2 V–1 s–1; these results are significantly higher than those obtained previously for the same molecule (1.0–5.0 cm2 V–1 s–1). Furthermore, the achieved mobility is also higher than the maximum reported electron mobility for organic materials (11 cm2 V–1 s–1). As a result, this work should greatly accelerate the advancement of organic electron-transporting materials.

  19. Universal tight binding model for chemical reactions in solution and at surfaces. III. Stoichiometric and reduced surfaces of titania and the adsorption of water

    SciTech Connect

    Lozovoi, A. Y.; Sheppard, T. J.; Kohanoff, J. J.; Pashov, D. L.; Paxton, A. T.

    2014-07-28

    We demonstrate a model for stoichiometric and reduced titanium dioxide intended for use in molecular dynamics and other atomistic simulations and based in the polarizable ion tight binding theory. This extends the model introduced in two previous papers from molecular and liquid applications into the solid state, thus completing the task of providing a comprehensive and unified scheme for studying chemical reactions, particularly aimed at problems in catalysis and electrochemistry. As before, experimental results are given priority over theoretical ones in selecting targets for model fitting, for which we used crystal parameters and band gaps of titania bulk polymorphs, rutile and anatase. The model is applied to six low index titania surfaces, with and without oxygen vacancies and adsorbed water molecules, both in dissociated and non-dissociated states. Finally, we present the results of molecular dynamics simulation of an anatase cluster with a number of adsorbed water molecules and discuss the role of edge and corner atoms of the cluster.

  20. Cationic superstructures and incommensurate magnetic structure in SbVO4 catalyst

    NASA Astrophysics Data System (ADS)

    Hernández-Velasco, J.; Vilanova-Martínez, P.; García-García, J.; Landa-Cánovas, A. R.

    2014-11-01

    Chemical and magnetic structure modulations in antimony vanadium mixed oxide with composition Sb0.92V1.08O4 prepared in reducing conditions are studied using diffraction techniques, mainly nuclear and magnetic neutron scattering, electron and X-ray powder diffraction. Magnetic susceptibility measurements show possible magnetic order of V3+ magnetic moments that is confirmed with neutron diffraction at TN ~50K. The average commensurate nuclear cell belongs to the tetragonal rutile structural type with cell constants: a=4.6066(11)Å and c=3.0812(8)Å at 60K. However the nature of the magnetic structure is incommensurate with propagation vector k= [0, 0, ± 0.266(1)] related to short range order phenomena and V-Sb alternating occupancy along the crystallographic c-axis.

  1. Superstructure formation in SrBa8[BN2]6 and EuBa8[BN2]6.

    PubMed

    Seidel, Stefan; Dierkes, Tobias; Jüstel, Thomas; Benndorf, Christopher; Eckert, Hellmut; Pöttgen, Rainer

    2016-07-26

    X-ray pure samples of SrBa8[BN2]6 and EuBa8[BN2]6 were synthesized from appropriate amounts of binary nitrides (Sr3N2, Ba3N2 and BN in sealed niobium ampoules and EuN, Ba3N2 and BN in BN crucibles, respectively) at temperatures up to 1370 K. The structure of SrBa8[BN2]6 was refined from single crystal X-ray diffractometer data: Fd3[combining macron]m, a = 1595.1(1) pm, wR(F(2)) = 0.0515, 387 F(2) values and 21 variables. EuBa8[BN2]6 has a lattice parameter of 1595.00(9) pm. Both nitridoborates adopt a new 2 × 2 × 2 superstructure variant of the LiCa4[BN2]3 type, realized through ordering of vacancies and Sr(2+) and Eu(2+) cations, respectively. The structures of SrBa8[BN2]6 and LiCa4[BN2]3 are related by a group-subgroup scheme. The Sr(2+)/vacancy ordering leads to an asymmetric coordination (1 × Sr(2+) and 8 × Ba(2+) in a distorted, mono-capped square prism) for the [BN2](3-) units with B-N distances of 132 and 136 pm. Vibrational spectra of SrBa8[BN2]6 and EuBa8[BN2]6 confirm the discrete linear [BN2](3-) units and (11)B solid state MAS NMR spectra are compatible with single crystallographic sites for the boron atoms. In EuBa8[BN2]6 the spectra are profoundly influenced by interactions of the (11)B nuclei with the unpaired electrons of the paramagnetic Eu(2+) ions. PMID:27397545

  2. Boundary conditions for free A-DNA in solution and the relation of local to global DNA structures at reduced water activity.

    PubMed

    Porschke, Dietmar

    2016-07-01

    Because of repeated claims that A-DNA cannot exist without aggregation or condensation, the state of DNA restriction fragments with 84-859 bp has been analyzed in aqueous solutions upon reduction of the water activity. Rotational diffusion times τ (d) measured by electric dichroism at different water activities with a wide variation of viscosities are normalized to values τ (c) at the viscosity of water, which indicate DNA structures at a high sensitivity. For short helices (chain lengths [Formula: see text] ≤ persistence length p), cooperative formation of A-DNA is reflected by the expected reduction of the hydrodynamic length; the transition to the A-form is without aggregation or condensation upon addition of ethanol at monovalent salt ≤1 mM. The aggregation boundary, indicated by a strong increase of τ (c), is shifted to higher monovalent salt (≥4 mM) when ethanol is replaced by trifluoroethanol. The BA transition is not indicated anymore by a cooperative change of τ (c) for [Formula: see text] » p; τ (c) values for these long chains decrease upon reduction of the water activity continuously over the full range, including the BA transition interval. This suggests a non-cooperative BC transition, which induces DNA curvature. The resulting wide distribution of global structures hides changes of local length during the BA transition. Free A-DNA without aggregation/condensation is found at low-salt concentrations where aggregation is inhibited and/or very slow. In an intermediate range of solvent conditions, where the A-form starts to aggregate, a time window remains that can be used for analysis of free A-DNA in a quasi-equilibrium state. PMID:26872482

  3. Stability of 2{radical} (2) {times}2{radical} (2) oxygen ordered superstructures in YBa{sub 2}Cu{sub 3}O{sub 6+x}

    SciTech Connect

    Aligia, A.A.; Koval, S.; Migoni, R.

    1998-01-01

    We have compared the ground-state energy of several observed or proposed {open_quotes}2{radical} (2) {times}2{radical} (2) oxygen ordered superstructures{close_quotes} [{open_quotes}herringbone{close_quotes} structures (HS{close_quote}s)], with those of {open_quotes}chain superstructures{close_quotes} (CS{close_quote}s) (in which the O atoms of the basal plane are ordered in chains), for different compositions x in YBa{sub 2}Cu{sub 3}O{sub 6+x}. The model Hamiltonian contains (i) the Madelung energy, (ii) a term linear in the difference between Cu and O hole occupancies which controls charge transfer, and (iii) covalency effects based on known results for t-J models in one and two dimensions. The optimum distribution of charge is determined, minimizing the total energy, and depends on two parameters which are determined from known results for x=1 and x=0.5. We obtain that on the O lean side, only CS{close_quote}s are stable, while for x=7/8, a HS with regularly spaced O vacancies added to the x=1 structure is more stable than the corresponding CS for the same x. We find that the detailed positions of the atoms in the structure and long-range Coulomb interactions are crucial for the electronic structure, the mechanism of charge transfer, the stability of the different phases, and the possibility of phase separation. {copyright} {ital 1998} {ital The American Physical Society}

  4. Novel EGCG assisted ultrasound synthesis of self-assembled Ca2SiO4:Eu(3+) hierarchical superstructures: Photometric characteristics and LED applications.

    PubMed

    Venkataravanappa, M; Nagabhushana, H; Darshan, G P; Daruka Prasad, B; Vijayakumar, G R; Premkumar, H B; Udayabhanu

    2016-11-01

    This paper reports for the first time ultrasound, EGCG assisted synthesis of pure and Eu(3+) (1-5mol%) activated Ca2SiO4 nanophosphors having self-assembled superstructures with high purity. The shape, size and morphology of the product were tuned by controlling influential parameters. It was found that morphology was highly dependent on EGCG concentration, sonication time, pH and sonication power. The probable formation mechanism for various hierarchical superstructures was proposed. The PL studies of Ca2SiO4:Eu(3+) phosphors can be effectively excited by the near ultraviolet (UV) (396nm) light and exhibited strong red emission around 613nm, which was attributed to the Eu(3+) ((5)D0→(7)F2) transition. The concentration quenching phenomenon was explained based on energy transfer between defect and Eu(3+) ions, electron-phonon coupling and Eu(3+)-Eu(3+) interaction. The Judd-Ofelt intensity parameters and radiative properties were estimated by using PL emission spectra. The photometric studies indicate that the obtained phosphors could be a promising red component for possible applications in the field of white light emitting diodes. PMID:27245974

  5. Mapping of reciprocal space of La0.30CoO2 in 3D: Analysis of superstructure diffractions and intergrowths with Co3O4

    NASA Astrophysics Data System (ADS)

    Brázda, Petr; Palatinus, Lukáš; Klementová, Mariana; Buršík, Josef; Knížek, Karel

    2015-07-01

    We have used electron diffraction tomography and powder X-ray diffraction to elucidate the structural properties of layered cobaltate γ-La0.30CoO2. The structure consists of hexagonal sheets of edge-sharing CoO6 octahedra interleaved by lanthanum monolayers. The La3+ cations occupy only one third of available P2 sites, forming a 2-dimensional a√3×a√3 superstructure in a-b plane. The results show that there exists no order in the mutual relative shift between the neighbouring La interlayers within the a-b plane. This is manifested in the observed monotonous decrease of the diffracted intensity of the superstructure diffractions along c* in both X-ray and electron diffraction data. The observed lack of stacking order differentiates the LaxCoO2 from its Ca and Sr analogues where at least a partial stacking order of the cationic interlayers is manifested in experimental data published in literature.

  6. Superstructure of a phosphor material Ba{sub 3}MgSi{sub 2}O{sub 8} determined by neutron diffraction data

    SciTech Connect

    Park, Cheol-Hee Hong, Seung-Tae; Keszler, Douglas A.

    2009-03-15

    Ba{sub 3}MgSi{sub 2}O{sub 8}, a phosphor host examined for use in white-light devices and plant-growth lamps, was synthesized at 1225 deg. C in air. Its crystal structure has been determined and refined by a combined powder X-ray and neutron Rietveld method (P3-bar, Z=3, a=9.72411(3) A, c=7.27647(3) A, V=595.870(5) A{sup 3}; R{sub p}/R{sub wp}=3.79%/5.03%, {chi}{sup 2}=4.20). Superstructure reflections, observed only in the neutron diffraction data, provided the means to establish the true unit cell and a chemically reasonable structure. The structure contains three crystallographically distinct Ba atoms-Ba1 resides in a distorted octahedral site with S{sub 6} (3-bar) symmetry, Ba2 in a nine-coordinate site with C{sub 3} (3) symmetry, and Ba3 in a ten-coordinate site with C{sub 1} (1) symmetry. The Mg atoms occupy distorted octahedral sites, and the Si atom occupies a distorted tetrahedral site. - Graphical Abstract: Crystal structure of Ba{sub 3}MgSi{sub 2}O{sub 8} viewed along the c direction. Superstructure reflections, observed only in the neutron diffraction data, provided the means to establish the true unit cell and a chemically reasonable structure.

  7. Controllable synthesis of 3D BiVO₄ superstructures with visible-light-induced photocatalytic oxidation of NO in the gas phase and mechanistic analysis.

    PubMed

    Ou, Man; Nie, Haoyu; Zhong, Qin; Zhang, Shule; Zhong, Lei

    2015-11-21

    A surfactant-free solvothermal method was developed for the controlled synthesis of diverse 3D ms-BiVO4 superstructures, including a flower, a double-layer half-open flower and a hollow tube with square cross-sections, via facilely adjusting the pH values with the aid of NH3·H2O. The effects of the morphologies of the prepared 3D ms-BiVO4 superstructure on the photocatalytic oxidation of NO were investigated, indicating that the enhanced photoactivity was not related to the surface area, but associated with the unique morphology, surface structure and good crystallinity. Moreover, the flower-like ms-BiVO4 photocatalyst with a more (040) reactive crystal plane exhibited higher photoactivity than those of other samples. The unique morphology helped with flushing the oxidation products accumulated on the surface of photocatalysts in the H2O2 system, and further improved the photoactivity. A trapping experiment was also conducted to examine the effects of the active species involved in the PCO of NO intuitively. PMID:26451402

  8. U1h Superstructure

    SciTech Connect

    Glen Sykes

    2000-11-01

    The U1H Shaft Project is a design build subcontract to supply the U. S. Department of Energy (DOE) a 1,045 ft. deep, 20 ft. diameter, concrete lined shaft for unspecified purposes. The subcontract awarded to Atkinson Construction by Bechtel Nevada to design and construct the shaft for the DOE has been split into phases with portions of the work being released as dictated by available funding. The first portion released included the design for the shaft, permanent hoist, headframe, and collar arrangement. The second release consisted of constructing the shaft collar to a depth of 110 ft., the service entry, utility trenches, and installation of the temporary sinking plant. The temporary sinking plant included the installation of the sinking headframe, the sinking hoist, two deck winches, the shaft form, the sinking work deck, and temporary utilities required to sink the shaft. Both the design and collar construction were completed on schedule. The third release consisted of excavating and lining the shaft to the station depth of approximately 950 feet. Work is currently proceeding on this production sinking phase. At a depth of approximately 600 feet, Atkinson has surpassed production expectation and is more than 3 months ahead of schedule. Atkinson has employed the use of a Bobcat 331 excavator as the primary means of excavation. the shaft is being excavated entirely in an alluvial deposit with varying degrees of calcium carbonate cementation. Several more work packages are expected to be released in the near future. The remaining work packages include, construction of the shaft station a depth of 975 ft. and construction of the shaft sump to a depth of 1,045 ft., installation of the loading pocket and station steel and equipment, installation of the shaft steel and guides, installation of the shaft utilities, and installation of the permanent headframe, hoist, collar utilities, and facilities.

  9. Superstructures and superconductivity

    SciTech Connect

    Fisk, Z.; Aeppli, G.

    1993-04-02

    Heavy fermion materials - so named because their conduction electrons behave as though they had extra mass - are like the cuprates in that they exhibit unusual superconducting properties. By the time the cuprates had been discovered, a good understanding of these materials was in hand. Unlike theories of high-[Tc] superconductivity, however, ideas about heavy fermions have not been the subject of great controversy. Thus, most of the effort in this backwater of condensed matter physics has focused on certain details of the behavior of one particularly well-studied compounds, UPt[sub 3]. The cause for sustained interest was that the process of developing ever more elaborate explanations for ever more elaborate experiments did not seem to converage. A recent paper by Midgley et al. reporting modulations in the crystal lattice of UPt[sub 3] suggests that theory and experiment might finally converge in a way that, while it does not threaten the broad understanding of heavy fermion systems, involves a degree of freedom ignored until now even in the face of past experience with elemental metallic uranium. Their transmission electron micrograph evidence for the existence of an incommensurate lattice modulation in UPt[sub 3] implicates this modulation as a probable source of the double superconducting transitions. Remarkably, the superconducting and magnetic coherence lengths, and the now discovered modulation period, are all of the same magnitude. For some time people have felt that stacking faults might be relevant to the properties of UPt[sub 3], but these new results are distinct from this. What Midgley et al. suggest is that the complicated superconducting phase diagram of UPt[sub 3] derives from the internal strain field caused by the modulation, and that this strain field lifts the degeneracy associated with unconventional pairing.

  10. Viscoelastic properties of aqueous guar gum derivative solutions under large amplitude oscillatory shear (LAOS).

    PubMed

    Szopinski, Daniel; Luinstra, Gerrit A

    2016-11-20

    The industrial relevant nonlinear viscoelastic properties of aqueous carboxymethyl hydroxypropyl guar gum (CMHPG) and non-ionic hydroxypropyl guar gum (HPG) solutions between semi-dilute and concentrated solution state were investigated by large amplitude oscillatory shear flow (LAOS). Aqueous CMHPG and HPG solutions enter the nonlinear flow regime at deformations γ0>100%. The nonlinear stress waveforms were analyzed by FT-rheology and orthogonal stress decomposition along the MITlaos framework. A rheological fingerprint is generated (Pipkin space) showing that the guar gum derivative solutions undergo a shear-thinning at high strains, which is preceded by a thickening above a minimum strain rate at intermediate strains. The influence and breakup of superstructures/aggregates gives a "rheological fingerprint", a function of the applied deformation and time scale (Pipkin space). A characteristic process time was found that scales exponentially with the overlap parameter with an exponent of 4/2, and is proposed to represent the relaxation process of the superstructure in solution. PMID:27561501

  11. Fully solution-processed transparent conducting oxide-free counter electrodes for dye-sensitized solar cells: spray-coated single-wall carbon nanotube thin films loaded with chemically-reduced platinum nanoparticles.

    PubMed

    Kim, Sang Yong; Kim, Yesel; Lee, Kyung Moon; Yoon, Woo Sug; Lee, Ho Seok; Lee, Jong Tae; Kim, Seung-Joo; Ahn, Yeong Hwan; Park, Ji-Yong; Lee, Tai Kyu; Lee, Soonil

    2014-08-27

    We report fully solution-processed fabrication of transparent conducting oxide-free counter electrodes (CEs) for dye-sensitized solar cells (DSSCs) by combining spray-coating of single-wall carbon nanotubes (SWCNTs) and chemical reduction of chloroplatinic acid precursor to platinum nanoparticles (Pt NPs) with formic acid. The power conversion efficiency of a semitransparent DSSC with such SWCNT-based CE loaded with Pt NPs is comparable to that of a control device with a conventional CE. Quantification of Pt loading shows that network morphology of entangled SWCNTs is efficient in forming and retaining chemically reduced Pt NPs. Moreover, electron microscopy and electrochemical impedance spectroscopy results show that mainly Pt NPs, which are tens of nanometers in diameter and reside at the surface of SWCNT CEs, contribute to electrocatalytic activity for triiodide reduction, to which we attribute strong correlation between power conversion efficiency of DSSCs and time constant deduced from equivalent-circuit analysis of impedance spectra. PMID:25122074

  12. Does an L-glutamine-containing, Glucose-free, Oral Rehydration Solution Reduce Stool Output and Time to Rehydrate in Children with Acute Diarrhoea? A Double-blind Randomized Clinical Trial

    PubMed Central

    Gutiérrez, Claudia; Villa, Sofía; Mota, Felipe R.; Calva, Juan J.

    2007-01-01

    This study assessed whether an oral rehydration solution (ORS) in which glucose is replaced by L-glutamine (L-glutamine ORS) is more effective than the standard glucose-based rehydration solution recommended by the World Health Organization (WHO-ORS) in reducing the stool volume and time to rehydrate in acute diarrhoea. In a double-blind, randomized controlled trial in a Mexican hospital, 147 dehydrated children, aged 1–60 month(s), were assigned either to the WHO-ORS (74 children), or to the L-glutamine ORS (73 children) and followed until successful rehydration. There were no significant differences between the groups in stool output during the first four hours, time to successful rehydration, volume of ORS required for rehydration, urinary output, and vomiting. This was independent of rotavirus-associated infection. An L-glutamine-containing glucose-free ORS seems not to offer greater clinical benefit than the standard WHO-ORS in mildly-to-moderately-dehydrated children with acute non-cholera diarrhoea. PMID:18330060

  13. Simultaneous spectrophotometric determination of orthophosphate and silicate ions in river water using ion-exclusion chromatography with an ascorbate solution as both eluent and reducing agent, followed by postcolumn derivatization with molybdate.

    PubMed

    Nakatani, Nobutake; Masuda, Wakako; Kozaki, Daisuke; Goto, Ryozo; Nakagoshi, Nobukazu; Mori, Masanobu; Hasebe, Kiyoshi; Tanaka, Kazuhiko

    2009-03-01

    Ion-exclusion chromatography was examined for the simultaneous spectrophotometric determinations of orthophosphate and silicate ions in river water using an ascorbate solution as both an eluent and a reducing agent, followed by postcolumn derivatization using molybdate. The detector responses for both ions increased with increased ascorbic acid concentration in the eluent, but peak tailing was observed for the orthophosphate ion. This suggests that the amounts of undissociated orthophosphate ions increased with decreased eluent pH, resulting in the penetration of the phosphate to the Donnan's membrane formed on the resin surface. Using a neutral sodium ascorbate solution as an eluent, the peak shape was improved. With optimized separation and derivatization conditions (eluent, 20 mM sodium ascorbate; color-forming reagent, 10 mM sodium molybdate-60 mM sulfuric acid; flow rates of eluent and color-forming reagent, 0.4 and 0.2 mL min(-1); coil length, 6 m), the detection limits of orthophosphate and silicate ions were 0.9 and 1.0 microg L(-1), respectively. This method was successfully applied to the determination of orthophosphate and silicate ions in Kurose River water and the quantitative evaluations of the effects of water intake to a reservoir and discharge from a biological sewage treatment plant on the fluxes of these ions in the river. PMID:19276594

  14. Superstructure of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} superconductors: A Raman scattering study

    SciTech Connect

    Loa, I.; Hofmann, J.; Litvinchuk, A.P.; Thomsen, C.; Zavaritsky, N.V.

    1996-12-31

    The authors present results of a Raman scattering study of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} single crystals with {Tc} = 95 K in a wide temperature (65--365 K) and frequency (from 640 down to 10 cm{sup {minus}1}) range. The features due to superstructure modulation are found in the low-frequency range. They also investigated additional lines seen in z(xx){bar z} and z(yy){bar z} scattering configurations in the regions of 160--240 cm{sup {minus}1} and 300--450 cm{sup {minus}1} and analyzed the temperature dependence of the latter.

  15. Nb{sub 2}OsB{sub 2}, with a new twofold superstructure of the U{sub 3}Si{sub 2} type: Synthesis, crystal chemistry and chemical bonding

    SciTech Connect

    Mbarki, Mohammed; Touzani, Rachid St.; Fokwa, Boniface P.T.

    2013-07-15

    The new ternary metal-rich boride, Nb{sub 2}OsB{sub 2}, was synthesized by arc-melting the elements in a water-cooled copper crucible under an argon atmosphere. The compound was characterized from single-crystal X-ray data and EDX measurements. It crystallizes as a new superstructure (space group P4/mnc, no. 128) of the tetragonal U{sub 3}Si{sub 2}-structure type with lattice parameters a=5.922(1) Å and c=6.879(2) Å. All of the B atoms are involved in B{sub 2} dumbbells with B–B distances of 1.89(4) Å. Structure relaxation using VASP (Vienna ab intio Simulation Package) has confirmed the space group and the lattice parameters. According to electronic structure calculations (TB–LMTO–ASA), the homoatomic B–B interactions are optimized and very strong, but relatively strong heteroatomic Os–B, Nb–B and Nb–Os bonds are also found: These interactions, which together build a three-dimensional network, are mainly responsible for the structural stability of this new phase. The density of state at the Fermi level predicts metallic behavior, as expected, from this metal-rich boride. - Graphical abstract: Nb{sub 2}OsB{sub 2} is, to the best of our knowledge, the first fully characterized phase in the ternary Nb–Os–B system. It crystallizes (space group P4/mnc, 128) with a new twofold superstructure of the U{sub 3}Si{sub 2} structure type (space group P4/mbm, 127), and is therefore the first boride in this structure family crystallizing with a superstructure of the U{sub 3}Si{sub 2} structure type. We show that the distortions leading to this superstructure occurs mainly in the Nb-layer, which tries to accommodate the large osmium atoms. The consequence of this puckering is the building osmium dumbbells instead of chains along [001]. - Highlights: • First compound in the Nb–Os–B system. • New twofold superstructure of U{sub 3}Si{sub 2} structure type. • Puckering of Nb-layer responsible for superstructure occurrence. • Chemical bonding studied

  16. Role of Planar Conformations in Aggregation Induced Spectral Shifts of Supermolecular Oligofluorenols in Solutions and Films: A Combined Experimental and MD/TD-DFT Study.

    PubMed

    Yuan, Xiangai; Zhang, Wanwan; Xie, Ling-Hai; Ma, Jing; Huang, Wei; Liu, Wenjian

    2015-08-13

    The supramolecular approach of fluorenol polymers brings about excellent self-assembly behavior to fabricate organogels and superstructured thin films through highly directional noncovalent interactions. To understand the aggregation effects on electronic structures, the packing structures and the UV/vis absorption spectra of oligofluorenols (PFOHn, n = 1/3-8), with and without OC8H17 side chains, were studied experimentally and theoretically in crystal, amorphous solids, and solutions, respectively. For the ground state in vacuum the steric repulsion between two adjacent fluorenol units renders the PFOH oligomers twisted in a helix conformation, while the molecular aggregation favors the appearance of planar π-conjugated structures. In comparison with the crystal packing, the content of planar conformation (with the torsion angle less than 20°) is increased in amorphous solids. The hydroxyl groups in oligofluorenols facilitate the formation of hydrogen bonding networks. The red shift in absorption spectra was observed in a systematic experimental study of unsubstituted and substituted oligofluorenols with the increasing concentration both in toluene and chloroform solutions. The subsitituted oligofluorenol R-PFOH1 with only one OC8H17 side chain exhibited a shoulder peak at 430-440 nm, which is different from PFOH1 without side chain and 3R-PFO1 with three OC8H17 side chain. Time-dependent density functional theory (TDDFT) calculations, which were carried out on conformation ensembles taken from a series of molecular dynamics (MD) simulations, revealed that the increase in the content of planar π-conjugated conformations is correlated to the red shift in the absorption spectra upon increasing the solution concentrations. The aggregation-induced red-shift in absorption spectra of oligofluorenols, as well as the blue-shift for oligothiophenes, was rationalized in a unified way from the increased (and reduced) content of planar conformations in molecular

  17. Temperature-based on-column solute focusing in capillary liquid chromatography reduces peak broadening from precolumn dispersion and volume overload when used alone or with solvent-based focusing

    PubMed Central

    Groskreutz, Stephen R.; Horner, Anthony R.; Weber, Stephen G.

    2015-01-01

    On-column focusing is essential for satisfactory performance using capillary scale columns. On-column focusing results from generating transient conditions at the head of the column that lead to high solute retention. Solvent-based on-column focusing is a well-known approach to achieve this. Temperature-assisted on-column focusing (TASF) can also be effective. TASF improves focusing by cooling a short segment of the column inlet to a temperature that is lower than the column temperature during the injection and then rapidly heating the focusing segment to the match the column temperature. A troublesome feature of an earlier implementation of TASF was the need to leave the capillary column unpacked in that portion of the column inside the fitting connecting it to the injection valve. We have overcome that problem in this work by packing the head of the column with solid silica spheres. In addition, technical improvements to the TASF instrumentation include: selection of a more powerful thermo-electric cooler to create faster temperature changes and electronic control for easy incorporation into conventional capillary instruments. Used in conjunction with solvent-based focusing and with isocratic elution, volumes of paraben samples (esters of p-hydroxybenzoic acid) up to 4.5-times the column liquid volume can be injected without significant bandspreading due to volume overload. Interestingly, the shapes of the peaks from the lowest volume injections that we can make, 30 nL, are improved when using TASF. TASF is very effective at reducing the detrimental effects of precolumn dispersion using isocratic elution. Finally, we show that TASF can be used to focus the neuropeptide galanin in a sample solvent with elution strength stronger than the mobile phase. Here, the stronger solvent is necessitated by the need to prevent peptide adsorption prior to and during analysis. PMID:26091787

  18. Polymorphism of NaVO2F2: a P2₁/c superstructure with pseudosymmetry of P2₁/m in the subcell.

    PubMed

    Yu, Zi-Qun; Wang, Jing-Quan; Huang, Ya-Xi; Botis, Sanda M; Pan, Yuanming; Mi, Jin-Xiao

    2015-06-01

    The ADDSYM routine in the program PLATON [Spek (2015). Acta Cryst. C71, 9-18] has helped researchers to avoid structures of (metal-)organic compounds being reported in an unnecessarily low symmetry space group. However, determination of the correct space group may get more complicated in cases of pseudosymmetric inorganic compounds. One example is NaVO2F2, which was reported [Crosnier-Lopez et al. (1994). Eur. J. Solid State Inorg. Chem. 31, 957-965] in the acentric space group P2₁ based on properties but flagged by ADDSYM as (pseudo)centrosymmetric P2₁/m within default distance tolerances. Herein a systematic investigation reveals that NaVO2F2 exists in at least four polymorphs: P2₁, (I), P2₁/m, (II), P2₁/c, (III), and one or more low-temperature ones. The new centrosymmetric modification, (III), with the space group P2₁/c has a similar atomic packing geometry to phase (I), except for having a doubled c axis. The double-cell of phase (III) arises from atomic shifts from the glide plane c at (x, ¼, z). With increasing temperature, the number of observed reflections decreases. The odd l reflections gradually become weaker and, correspondingly, all atoms shift towards the glide plane, resulting in a gradual second-order transformation of (III) into high-temperature phase (II) (P2₁/m) at below 493 K. At least one first-order enantiotropic phase transition was observed below 139 K from both the single-crystal X-ray diffraction and the differential scanning calorimetry analyses. Periodic first-principles calculations within density functional theory show that both P2₁/c superstructure (III) and P2₁ substructure (I) are more stable than P2₁/m structure (II), and that P2₁/c superstructure (III) is more stable that P2₁ substructure (I). PMID:26044323

  19. Magnetic field directed assembly of superstructures of ferrite-ferroelectric core-shell nanoparticles and studies on magneto-electric interactions

    SciTech Connect

    Srinivasan, G. Sreenivasulu, G.; Benoit, Crystal; Petrov, V. M.; Chavez, F.

    2015-05-07

    Composites of ferromagnetic and ferroelectric are of interest for studies on mechanical strain mediated magneto-electric (ME) interactions and for useful technologies. Here, we report on magnetic-field-assisted-assembly of barium titanate (BTO)-nickel ferrite (NFO) core-shell particles into linear chains and 2D/3D arrays and measurements of ME effects in such assemblies. First, we synthesized the core-shell nano-particles with 50–600 nm BTO and 10–200 nm NFO by chemical self-assembly by coating the ferroic particles with complementary coupling groups and allowing them to self-assemble in the presence of a catalyst via the “click” reaction. The core-shell structure was confirmed with electron microscopy and scanning probe microscopy. We obtained superstructure of the core-shell particles by subjecting them to a magnetic field gradient that exerts an attractive force on the particles and align them toward the regions of high field strengths. At low particle concentration, linear chains were formed and they evolved into 2D and 3D arrays at high particle concentrations. Magnetoelectric characterization on unassembled films and assembled arrays has been performed through measurements of low-frequency ME voltage coefficient (MEVC) by subjecting the sample to a bias magnetic field and an ac magnetic field. The MEVC is higher for field-assembled samples than for unassembled films and is found to be sensitive to field orientation with a higher MEVC for magnetic fields parallel to the array direction than for magnetic fields perpendicular to the array. A maximum MEVC of 20 mV/cm Oe, one of the highest reported for any bulk nanocomposite, is measured across the array thickness. A model is provided for ME coupling in the superstructures of BTO-NFO particulate composites. First, we estimated the MEVC for a free-standing BTO-NFO core-shell particle and then extended the model to include an array of linear chains of the particles. The theoretical estimates are in

  20. Mapping of reciprocal space of La{sub 0.30}CoO{sub 2} in 3D: Analysis of superstructure diffractions and intergrowths with Co{sub 3}O{sub 4}

    SciTech Connect

    Brázda, Petr; Knížek, Karel

    2015-07-15

    We have used electron diffraction tomography and powder X-ray diffraction to elucidate the structural properties of layered cobaltate γ-La{sub 0.30}CoO{sub 2}. The structure consists of hexagonal sheets of edge-sharing CoO{sub 6} octahedra interleaved by lanthanum monolayers. The La{sup 3+} cations occupy only one third of available P2 sites, forming a 2-dimensional a√3×a√3 superstructure in a–b plane. The results show that there exists no order in the mutual relative shift between the neighbouring La interlayers within the a–b plane. This is manifested in the observed monotonous decrease of the diffracted intensity of the superstructure diffractions along c{sup ⁎} in both X-ray and electron diffraction data. The observed lack of stacking order differentiates the La{sub x}CoO{sub 2} from its Ca and Sr analogues where at least a partial stacking order of the cationic interlayers is manifested in experimental data published in literature. - Highlights: • We use electron diffraction tomography for reciprocal space mapping of La{sub 0.30}CoO{sub 2}. • We observed a complete disorder of the stacking of Lanthanum interlayers. • Co{sub 3}O{sub 4} intergrown with La{sub 0.30}CoO{sub 2} crystals brings about fake superstructure diffractions. • Twinning of Co{sub 3}O{sub 4} enhances the problem of fake superstructure diffractions.

  1. Superstructure in the Metastable Intermediate-Phase Li2/3 FePO4 Accelerating the Lithium Battery Cathode Reaction.

    PubMed

    Nishimura, Shin-ichi; Natsui, Ryuichi; Yamada, Atsuo

    2015-07-27

    LiFePO4 is an important cathode material for lithium-ion batteries. Regardless of the biphasic reaction between the insulating end members, Lix FePO4 , x≈0 and x≈1, optimization of the nanostructured architecture has substantially improved the power density of positive LiFePO4 electrode. The charge transport that occurs in the interphase region across the biphasic boundary is the primary stage of solid-state electrochemical reactions in which the Li concentrations and the valence state of Fe deviate significantly from the equilibrium end members. Complex interactions among Li ions and charges at the Fe sites have made understanding stability and transport properties of the intermediate domains difficult. Long-range ordering at metastable intermediate eutectic composition of Li2/3 FePO4 has now been discovered and its superstructure determined, which reflected predominant polaron crystallization at the Fe sites followed by Li(+) redistribution to optimize the Li-Fe interactions. PMID:26074480

  2. Proposal for realizing high-efficiency III-nitride semiconductor tandem solar cells with InN/GaN superstructure magic alloys fabricated at raised temperature (SMART)

    NASA Astrophysics Data System (ADS)

    Kusakabe, Kazuhide; Yoshikawa, Akihiko

    2014-03-01

    We propose a plausible and realistic idea for realizing high-efficiency III-nitride semiconductor tandem solar cells which utilize nearly entire AM-1.5 solar spectrum conversion under a subcell photocurrent matching rule. For the sake of drastic improvement/suppression of pn-junction leakage current, each subcell in the proposed tandem solar cells is composed of superstructure InN/GaN magic alloys, i.e. coherently grown (InN)m/(GaN)n short-period superlattices with simple integer pairs of (m, n) <= 4 in monolayers, which solve lattice-mismatch and immiscible problems in a conventional InGaN ternary alloy system. The InN/GaN magic alloys are further applicable to band engineering that provides potential wells for a thermal/photo sensitization effect and graded-bandgap structures for efficient carrier collection under the same (m, n) ratio alloys or keeping the coherent structure. Theoretical maximum conversion efficiency is 51% (58% under 250-suns concentration) for a 4-tandem cell configuration.

  3. Deciphering the aggregation mechanism of bacteria (Shewanella oneidensis MR1) in the presence of polyethyleneimine: Effects of the exopolymeric superstructure and polymer molecular weight.

    PubMed

    Krapf, Marie-Eve M; Lartiges, Bruno; Merlin, Christophe; Francius, Grégory; Ghanbaja, Jaafar; Duval, Jérôme F L

    2016-03-01

    Aggregation tests between bacteria and Polyethyleneimine (PEI) of low (600g/mol) and high (750,000g/mol) molecular weight were performed in order to address the physico-chemical mechanisms underlying the interactions between cationic polymer and bacterial membranes. The selected strain, Schewanella oneidensis MR-1, produces a lipopolysaccharide (LPS) of various lengths depending on the growth conditions. Optical density, bioaggregate size, electrophoretic mobility measurements, TEM and AFM observations, and cell lysis tests (crystal violet release), were collected to describe the PEI-mediated aggregation of LPS-O-antigen-free and LPS-O-antigen-decorated bacteria. The results show that PEI of low molecular weight (600g/mol) fails to aggregate bacteria, whereas PEIs of higher molecular weight (60,000 and 750,000g/mol) lead to flocculation at low polymer concentrations. In addition, the LPS-O antigen bacterial superstructure is shown to act as a protective barrier, thus delaying the harmful effects of the cationic polymer. Despite this protection, the interaction of bacterial membranes with increasing concentrations of PEI leads to a series of deleterious processes including biosurface modification (peeling, membrane permeabilization and/or lysis), aggregation of bacterial cells, and complexation of PEI with both released biosurface fragments and cytoplasmic residues issued from lysis. PMID:26774052

  4. Reducing disinfectant wastage.

    PubMed

    Kaye, S B; Graham, R; McCarthy, K; Green, J R; Damjanovic, V; Austin, M

    1991-01-01

    In order to lower departmental costs in an ophthalmological outpatient department by reducing wastage, the stability of available chlorine at levels of 280 ppm and 560 ppm in litre solutions of sodium dichloroisocyanurate was investigated over a three-week period. There was no significant decay in available chlorine at these levels in solutions kept at 20 degrees C. Sodium dichloroisocyanurate may be prepared on a weekly instead of a daily basis with an annual saving of 1200 pounds to 1400 pounds. PMID:2060659

  5. Light-Emitting Superstructures with Anion Effect: Coordination-Driven Self-Assembly of Pure Tetraphenylethylene Metallacycles and Metallacages.

    PubMed

    Yan, Xuzhou; Wang, Ming; Cook, Timothy R; Zhang, Mingming; Saha, Manik Lal; Zhou, Zhixuan; Li, Xiaopeng; Huang, Feihe; Stang, Peter J

    2016-04-01

    Herein, we describe the synthesis of tetraphenylethylene (TPE)-based di-Pt(II) acceptors as shown by X-ray analysis, which are subsequently used to construct pure TPE-based 2D hexagonal metallacycles and 3D drumlike metallacages with three different counteranions via coordination-driven self-assembly. The metallacycles possess alternating TPE donor and acceptor units that arrange 12 pendant phenyl rings along the outer perimeter that provide the basis for the observed aggregation-induced emission (AIE) behavior. The metallacages are similarly constructed from TPE-based building blocks, specifically two donors and four acceptors, resulting in eight freely rotating phenyl rings decorating the prismatic core. The fluorescence of these cages in dilute solution is intensified when hexane is added to CH2Cl2 solutions, indicative of aggregation-induced enhanced emission (AIEE). The influence of the counteranions on the photophysics of the assemblies was investigated. The molar absorption coefficients (ε), fluorescence emission intensities, and quantum yield (ΦF) values of the SCCs with different counteranions in CH2Cl2 follow the order PF6(-) > OTf(-) > NO3(-). The same trend also applies to the AIE characteristics of the SCCs in the aggregated state. The metal-organic materials developed here not only enrich a newly emerging library of self-assembly AIE metallacycles and cages that are promising candidates for turn-on fluorescent sensors and advanced optical devices but also provide an understanding of how structural factors affect the photophysics of AIE-active SCCs. PMID:26982213

  6. METHOD OF REDUCING PLUTONIUM COMPOUNDS

    DOEpatents

    Johns, I.B.

    1958-06-01

    A method is described for reducing plutonium compounds in aqueous solution from a higher to a lower valence state. This reduction of valence is achieved by treating the aqueous solution of higher valence plutonium compounds with hydrogen in contact with an activated platinum catalyst.

  7. Technetium recovery from high alkaline solution

    DOEpatents

    Nash, Charles A.

    2016-07-12

    Disclosed are methods for recovering technetium from a highly alkaline solution. The highly alkaline solution can be a liquid waste solution from a nuclear waste processing system. Methods can include combining the solution with a reductant capable of reducing technetium at the high pH of the solution and adding to or forming in the solution an adsorbent capable of adsorbing the precipitated technetium at the high pH of the solution.

  8. Reducing Dropouts.

    ERIC Educational Resources Information Center

    Timpane, Michael; And Others

    A group of three conference papers, all addressing the subject of effective programs to decrease the number of school dropouts, is presented in this document. The first paper, "Systemic Approaches to Reducing Dropouts" (Michael Timpane), asserts that dropping out is a symptom of failures in the social, economic, and educational systems. Dropping…

  9. Electromarking solution

    DOEpatents

    Bullock, Jonathan S.; Harper, William L.; Peck, Charles G.

    1976-06-22

    This invention is directed to an aqueous halogen-free electromarking solution which possesses the capacity for marking a broad spectrum of metals and alloys selected from different classes. The aqueous solution comprises basically the nitrate salt of an amphoteric metal, a chelating agent, and a corrosion-inhibiting agent.

  10. Self-assembly of multiferroic core-shell particulate nanocomposites through DNA-DNA hybridization and magnetic field directed assembly of superstructures

    NASA Astrophysics Data System (ADS)

    Sreenivasulu, Gollapudi; Lochbiler, Thomas A.; Panda, Manashi; Srinivasan, Gopalan; Chavez, Ferman A.

    2016-04-01

    Multiferroic composites of ferromagnetic and ferroelectric phases are of importance for studies on mechanical strain mediated coupling between the magnetic and electric subsystems. This work is on DNA-assisted self-assembly of superstructures of such composites with nanometer periodicity. The synthesis involved oligomeric DNA-functionalized ferroelectric and ferromagnetic nanoparticles, 600 nm BaTiO3 (BTO) and 200 nm NiFe2O4 (NFO), respectively. Mixing BTO and NFO particles, possessing complementary DNA sequences, resulted in the formation of ordered core-shell heteronanocomposites held together by DNA hybridization. The composites were imaged by scanning electron microscopy and scanning microwave microscopy. The presence of heteroassemblies along with core-shell architecture is clearly observed. The reversible nature of the DNA hybridization allows for restructuring the composites into mm-long linear chains and 2D-arrays in the presence of a static magnetic field and ring-like structures in a rotating-magnetic field. Strong magneto-electric (ME) coupling in as-assembled composites is evident from static magnetic field H induced polarization and low-frequency magnetoelectric voltage coefficient measurements. Upon annealing the nanocomposites at high temperatures, evidence for the formation of bulk composites with excellent cross-coupling between the electric and magnetic subsystems is obtained by H-induced polarization and low-frequency ME voltage coefficient. The ME coupling strength in the self-assembled composites is measured to be much stronger than in bulk composites with randomly distributed NFO and BTO prepared by direct mixing and sintering.

  11. Superstructure in RE2-xFe4Si14-y (RE = Y, Gd-Lu) characterized by diffraction, electron microscopy, and Mössbauer spectroscopy.

    PubMed

    Han, Mi-Kyung; Wu, Ya-Qiao; Kramer, Matthew; Vatovez, Benjamin; Grandjean, Fernande; Long, Gary J; Miller, Gordon J

    2006-12-25

    Ternary rare-earth iron silicides RE(2-x)Fe4Si(14-y) (RE = Y, Gd-Lu; x approximately equal to 0.8; y approximately equal to 4.1) crystallize in the hexagonal system with a approximately equal to 3.9 A, c approximately equal to 15.3 A, Pearson symbol hP20-4.9. Their structures involve rare-earth silicide planes with approximate compositions of "RE1.2Si1.9" alternating with beta-FeSi2-derived slabs and are part of a growing class of rare-earth/transition-metal/main-group compounds based on rare-earth/main-group element planes interspersed with (distorted) fluorite-type transition-metal/main-group element layers. The rare-earth silicide planes in the crystallographic unit cells show partial occupancies of both the RE and Si sites because of interatomic distance constraints. Transmission electron microscopy reveals a 4a x 4b x c superstructure for these compounds, whereas further X-ray diffraction experiments suggest ordering within the ab planes but disordered stacking along the c direction. A 4a x 4b structural model for the rare-earth silicide plane is proposed, which provides good agreement with the electron microscopy results and creates two distinct Fe environments in a 15:1 ratio. Fe-57 Mössbauer spectra confirm these two different iron environments in the powder samples. Magnetic susceptibilities suggest weak (essentially no) magnetic coupling between rare-earth elements, and resistivity measurements indicate poor metallic behavior with a large residual resistivity at low temperatures, which is consistent with disorder. First-principles electronic-structure calculations on model structures identify a pseudogap in the densities of states for specific valence-electron counts that provides a basis for a useful electron-counting scheme for this class of rare-earth/transition-metal/main-group compounds. PMID:17173406

  12. Apparatus for reducing solvent luminescence background emissions

    DOEpatents

    Affleck, R.L.; Ambrose, W.P.; Demas, J.N.; Goodwin, P.M.; Johnson, M.E.; Keller, R.A.; Petty, J.T.; Schecker, J.A.; Wu, M.

    1998-11-10

    The detectability of luminescent molecules in solution is enhanced by reducing the background luminescence due to impurity species also present in the solution. A light source that illuminates the solution acts to photolyze the impurities so that the impurities do not luminesce in the fluorescence band of the molecule of interest. Molecules of interest may be carried through the photolysis region in the solution or may be introduced into the solution after the photolysis region. 6 figs.

  13. Apparatus for reducing solvent luminescence background emissions

    DOEpatents

    Affleck, Rhett L.; Ambrose, W. Patrick; Demas, James N.; Goodwin, Peter M.; Johnson, Mitchell E.; Keller, Richard A.; Petty, Jeffrey T.; Schecker, Jay A.; Wu, Ming

    1998-01-01

    The detectability of luminescent molecules in solution is enhanced by reducing the background luminescence due to impurity species also present in the solution. A light source that illuminates the solution acts to photolyze the impurities so that the impurities do not luminesce in the fluorescence band of the molecule of interest. Molecules of interest may be carried through the photolysis region in the solution or may be introduced into the solution after the photolysis region.

  14. Comment on {open_quote}{open_quote}Superconductivity and Madelung potential of YBa{sub 2}Cu{sub 3}O{sub 6+{ital x}} ordered superstructures{close_quote}{close_quote}

    SciTech Connect

    Ukrainskii, I.I.; Shramko, O.V.

    1996-11-01

    We note discrepancies in numerical results in our calculations of the Coulomb potentials in YBa{sub 2}Cu{sub 3}O{sub 6+{ital x}} ({ital x} = 0, 0.5, 1) with those given by Wang {ital et} {ital al}. in {open_quote}{open_quote}Superconductivity and Madelung potential of YBa{sub 2}Cu{sub 3}O{sub 6+{ital x}} ordered superstructures{close_quote}{close_quote} [Phys. Rev. B {bold 45}, 10834 (1992)]. {copyright} {ital 1996 The American Physical Society.}

  15. Reducing the In2O3(111) Surface Results in Ordered Indium Adatoms

    SciTech Connect

    Wagner, Margareta; Seiler, Steffen; Meyer, Bernd; Boatner, Lynn A; Schmid, M.; Diebold, U.

    2014-01-01

    The In2O3(111) surface can be transformed from an oxidized bulk termination to one that is covered by single In adatoms. As each adatom sits at one specific site within the surface unit cell they form a well-ordered (1 1) superstructure. Annealing at 500 C in O2 or in ultrahigh vacuum results in a fully reversible conversion between these two surface terminations; this transformation and intermediate stages were followed with Scanning Tunneling Microscopy (STM). Formation of this novel surface structure under reducing conditions is corroborated by Density Functional Theory (DFT). The reduced adatom-covered and the oxidized In2O3(111) surfaces are expected to exhibit different chemical and electronic properties, which can easily be exploited by the facile and reversible switching between the two terminations.

  16. pH-Responsive poly(itaconic acid-co-N-vinylpyrrolidone) hydrogels with reduced ionic strength loading solutions offer improved oral delivery potential for high isoelectric point-exhibiting therapeutic proteins.

    PubMed

    Koetting, Michael C; Peppas, Nicholas A

    2014-08-25

    pH-Responsive hydrogels comprised of itaconic acid copolymerized with N-vinylpyrrolidone (P(IA-co-NVP)) were synthesized and tested as carriers for the oral delivery of high isoelectric point (pI) exhibiting therapeutic proteins. Swelling studies show that P(IA-co-NVP) hydrogels exhibit significantly greater and faster pH-responsive swelling than previously studied methacrylic acid-based hydrogels, achieving up to 68% greater equilibrium swelling and 10.4 times greater swelling in time-limited experiments. Using salmon calcitonin as a model high pI protein therapeutic, we show that P(IA-co-NVP) hydrogels exhibit significantly greater delivery potential than methacrylic acid-based hydrogels. Additionally, we show that utilizing a lower ionic strength solution during drug loading significantly improves drug delivery potential for high pI therapeutics. By using a 1.5mM PBS buffer rather than the standard 150 mM PBS buffer during loading, up to 83 times as much calcitonin can be delivered in neutral conditions, with up to a 9.6-fold improvement in percent release. Using P(IA-co-NVP) hydrogel microparticles and a low ionic strength loading solution, up to 48 μg calcitonin/mg hydrogel can be delivered in small intestinal conditions. Based on expected absorption in the small intestine, this is sufficient delivery potential for achieving therapeutic dosage via a single, regularly-sized pill taken daily. PMID:24853463

  17. A new anion-deficient fluorite-related superstructure of Bi{sub 28}V{sub 8}O{sub 62}

    SciTech Connect

    Đorđević, T.; Karanović, Lj.

    2014-12-15

    New hydrothermally synthesized Bi{sub 28}V{sub 8}O{sub 62} was structurally characterized using single-crystal X-ray diffraction data. Bi{sub 28}V{sub 8}O{sub 62} crystallizes in the novel type of defect fluorite structure related to the face-centered cubic δ-Bi{sub 2}O{sub 3}. It is monoclinic, s. g. P2{sub 1}/c, and the relation to the fluorite subcell is given as a∼(3/2)a{sub F}+(3/2)c{sub F}; b∼ −b{sub F}; c∼2a{sub F} −4c{sub F} (F in subscript indicate the unit cell parameter of fluorite). Its structure is characterized by slabs of edge sharing OBi{sub 4} tetrahedra surrounded by the OBi{sub 3} triangles. As a part of these OBi{sub 3} triangles, two positionally disordered Bi{sup 3+} cations were observed in the marginal part of the slabs. The slabs are extending along b axis and are linked by inter-slab portion of the structure composed of VO{sub 4} tetrahedra and BiO{sub 6−x} coordination polyhedra, where x is a number of vacant oxygen sites. Raman spectra verified the coordination environment of vanadium atoms in the structure. - Graphical abstract: The [4{sup ¯}01] projection of two slabs and inter-slab part of the structure in one layer parallel to the (3{sup ¯}08)=(002{sup ¯}){sub F} plane (F in subscript indicate a fluorite type structure). The large green circles are Bi atoms. Small blue circles represent partly and fully occupied O sites, respectively. Pink (hatched black) are V1O{sub 4} and blue (hatched white) are V2O{sub 4} coordination tetrahedra. - Highlights: • Single crystals of Bi{sub 28}V{sub 8}O{sub 62} were grown using hydrothermal technique. • The crystal structure of Bi{sub 28}V{sub 8}O{sub 62} was solved using single-crystal XRD method. • Bi{sub 28}V{sub 8}O{sub 62} has an anion-deficient fluorite-related superstructure. • Raman spectrum confirmed the coordination environment of vanadium atoms. • Relation to the structurally related compound was discussed.

  18. Rational design of hierarchical ZnO superstructures for efficient charge transfer: mechanistic and photovoltaic studies of hollow, mesoporous, cage-like nanostructures with compacted 1D building blocks.

    PubMed

    Chetia, Tridip Ranjan; Ansari, Mohammad Shaad; Qureshi, Mohammad

    2016-02-21

    Mesoporous and hollow zinc oxide (ZnO) hierarchical superstructures assembled with compact 1D building blocks that provide an efficient and faster transport pathway for photo-generated charge carriers have been synthesized using a biomass derived polysaccharide "alginic acid". To understand the interactions between the organic bio-template and inorganic growth units of ZnO in aqueous medium, the effects of additives such as the alginate ion (ALGI) and ammonium hydroxide (NH4OH), along with the controlled reaction conditions, are investigated using Field Emission Scanning Electron Microscopy (FESEM) and powder X-ray diffraction. Dynamic and steady-state photoluminescence measurements are carried out to understand the charge transfer processes in the compact 1D superstructures. Experimental analyses reveal that the alginate ions, under hydrothermal reaction conditions, act as a structure directing agent and assemble 1D ZnO nanorods (NRs) hierarchically while NH4OH assists the formation of ZnO growth units. A plausible mechanism for ZnO cage formation is proposed based on the experimental observations. Morphology dependent photovoltaic properties of ZnO heterostructures, i.e., for ZnO cages, ZnO NRs and ZnO PNPs, have been studied along with electrochemical impedance spectroscopy (EIS). Enhancement of ∼ 60% and ∼ 35% in power conversion efficiency (PCE) is observed in ZnO cage based devices as compared to ZnO NR- and ZnO PNP-based devices, respectively. PMID:26818181

  19. Polymer solutions

    SciTech Connect

    Krawczyk, Gerhard Erich; Miller, Kevin Michael

    2011-07-26

    There is provided a method of making a polymer solution comprising polymerizing one or more monomer in a solvent, wherein said monomer comprises one or more ethylenically unsaturated monomer that is a multi-functional Michael donor, and wherein said solvent comprises 40% or more by weight, based on the weight of said solvent, one or more multi-functional Michael donor.

  20. Sound Solutions

    ERIC Educational Resources Information Center

    Starkman, Neal

    2007-01-01

    Poor classroom acoustics are impairing students' hearing and their ability to learn. However, technology has come up with a solution: tools that focus voices in a way that minimizes intrusive ambient noise and gets to the intended receiver--not merely amplifying the sound, but also clarifying and directing it. One provider of classroom audio…

  1. Compatible solutes

    PubMed Central

    Hill, Colin

    2010-01-01

    Recently we reported a role for compatible solute uptake in mediating bile tolerance and increased gastrointestinal persistence in the foodborne pathogen Listeria monocytogenes.1 Herein, we review the evolution in our understanding of how these low molecular weight molecules contribute to growth and survival of the pathogen both inside and outside the body, and how this stress survival mechanism may ultimately be used to target and kill the pathogen. PMID:21326913

  2. Solutions Network Formulation Report. Reducing Light Pollution in U.S. Coastal Regions Using the High Sensitivity Cameras on the SAC-C and Aquarius/SAC-D Satellites

    NASA Technical Reports Server (NTRS)

    Andrews, Jane C.; Knowlton, Kelly

    2007-01-01

    Light pollution has significant adverse biological effects on humans, animals, and plants and has resulted in the loss of our ability to view the stars and planets of the universe. Over half of the U.S. population resides in coastal regions where it is no longer possible to see the stars and planets in the night sky. Forty percent of the entire U.S. population is never exposed to conditions dark enough for their eyes to convert to night vision capabilities. In coastal regions, urban lights shine far out to sea where they are augmented by the output from fishing boat, cruise ship and oil platform floodlights. The proposed candidate solution suggests using HSCs (high sensitivity cameras) onboard the SAC-C and Aquarius/SAC-D satellites to quantitatively evaluate light pollution at high spatial resolution. New products modeled after pre-existing, radiance-calibrated, global nighttime lights products would be integrated into a modified Garstang model where elevation, mountain screening, Rayleigh scattering, Mie scattering by aerosols, and atmospheric extinction along light paths and curvature of the Earth would be taken into account. Because the spatial resolution of the HSCs on SAC-C and the future Aquarius/SAC-D missions is greater than that provided by the DMSP (Defense Meteorological Satellite Program) OLS (Operational Linescan System) or VIIRS (Visible/Infrared Imager/Radiometer Suite), it may be possible to obtain more precise light intensity data for analytical DSSs and the subsequent reduction in coastal light pollution.

  3. The solution structure of the N-terminal domain of E3L shows a tyrosine conformation that may explain its reduced affinity to Z-DNA in vitro

    PubMed Central

    Kahmann, Jan D.; Wecking, Diana A.; Putter, Vera; Lowenhaupt, Ky; Kim, Yang-Gyun; Schmieder, Peter; Oschkinat, Hartmut; Rich, Alexander; Schade, Markus

    2004-01-01

    The N-terminal domain of the vaccinia virus protein E3L (ZαE3L) is essential for full viral pathogenicity in mice. It has sequence similarity to the high-affinity human Z-DNA-binding domains ZαADAR1 and ZαDLM1. Here, we report the solution structure of ZαE3L and the chemical shift map of its interaction surface with Z-DNA. The global structure and the Z-DNA interaction surface of ZαE3L are very similar to the high-affinity Z-DNA-binding domains ZαADAR1 and ZαDLM1. However, the key Z-DNA contacting residue Y48 of ZαE3L adopts a different side chain conformation in unbound ZαE3L, which requires rearrangement for binding to Z-DNA. This difference suggests a molecular basis for the significantly lower in vitro affinity of ZαE3L to Z-DNA compared with its homologues. PMID:14981270

  4. Fourier transform infrared spectroscopy of 2'-deoxycytidine aggregates in CDCl3 solutions.

    PubMed

    Biemann, Lars; Häber, Thomas; Maydt, Daniela; Schaper, Klaus; Kleinermanns, Karl

    2011-03-21

    We investigated the self-aggregation of 2'-deoxy-3',5'-bis(tert-butyldimethylsilyl)-cytidine dC(TBDMS)(2) in CDCl(3) solutions by Fourier transform infrared (FT-IR) spectroscopy and report the formation of larger aggregates than dimers in this solvent for the first time. The hydrogen bonding patterns in these complexes, which occur with increasing concentration may serve as a model for DNA super-structures such as triplexes. From the IR spectra, wavelength dependent absolute extinction coefficients of the monomer, dimer as well as a contribution from larger clusters which are supposedly trimers are deduced on the basis of a simple deconvolution method. Our results are supported by RI-B3LYP/TZVP calculations within the conductorlike screening model framework, to account for solvent effects in the ab initio calculations. PMID:21428667

  5. The phase diagram and tetragonal superstructures of the rare earth cobaltate phases Ln1- xSr xCoO 3- δ ( Ln=La 3+, Pr 3+, Nd 3+, Sm 3+, Gd 3+, Y 3+, Ho 3+, Dy 3+, Er 3+, Tm 3+ and Yb 3+)

    NASA Astrophysics Data System (ADS)

    James, M.; Cassidy, D.; Goossens, D. J.; Withers, R. L.

    2004-06-01

    Single phase perovskite-based rare earth cobaltates ( Ln1- xSr xCoO 3- δ) ( Ln=La 3+, Pr 3+, Nd 3+, Sm 3+, Gd 3+, Dy 3+, Y 3+, Ho 3+, Er 3+, Tm 3+ and Yb 3+; 0.67⩽ x⩽0.9) have been synthesized at 1100°C under 1 atmosphere of oxygen. X-ray diffraction of phases containing the larger rare earth ions La 3+, Pr 3+ and Nd 3+ reveals simple cubic structures; however electron diffraction shows orientational twinning of a local, tetragonal ( I4/ mmm; ap× ap×2 ap) superstructure phase. Orientational twinning is also present for Ln1- xSr xCoO 3- δ compounds containing rare earth ions smaller than Nd 3+. These compounds show a modulated intermediate parent with a tetragonal superstructure ( I4/ mmm; 2 ap×2 ap×4 ap). Thermogravimetric measurements have determined the overall oxygen content, and these phases show mixed valence (3 +/4 +) cobalt oxidation states with up to 50% Co(IV). X-ray diffraction data and Rietveld techniques have been used to refine the structures of each of these tetragonal superstructure phases ( Ln=Sm 3+-Yb 3+). Coupled Ln/Sr and oxygen/vacancy ordering and associated structural relaxation are shown to be responsible for the observed superstructure.

  6. Energy Solutions

    ERIC Educational Resources Information Center

    Sobieski, Jeff

    2010-01-01

    Education facilities managers are faced with a daunting set of challenges: They must find new ways to reduce energy consumption and carry out greener energy policies. HVAC typically accounts for more than 30% of a building's electricity costs, so there is a clear incentive to eliminate unnecessary heating and cooling of unoccupied rooms. With more…

  7. Zr{sub 2}Ir{sub 6}B with an eightfold superstructure of the cubic perovskite-like boride ZrIr{sub 3}B{sub 0.5}: Synthesis, crystal structure and bonding analysis

    SciTech Connect

    Hermus, Martin; Fokwa, Boniface P.T.

    2010-04-15

    Single phase powder samples and single crystals of Zr{sub 2}Ir{sub 6}B were successfully synthesized by arc-melting the elements in a water-cooled copper crucible under an argon atmosphere. Superstructure reflections were observed both on powder and on single crystal diffraction data, leading to an eightfold superstructure of ZrIr{sub 3}B{sub x} phase. The new phase, which has a metallic luster, crystallizes in space group Fm3-barm (no. 225) with the lattice parameters a=7.9903(4) A, V=510.14(4) A{sup 3}. Its crystal structure was refined on the basis of powder as well as single crystal data. The single crystal refinement converged to R{sub 1}=0.0239 and wR{sub 2}=0.0624 for all 88 unique reflections and 6 parameters. Zr{sub 2}Ir{sub 6}B is isotypic to Ti{sub 2}Rh{sub 6}B and its structure can be described as a defect double perovskite, A{sub 2}BB'O{sub 6}, where the A site is occupied by zirconium, the B site by boron, the O site by iridium but the B' site is vacant, leading to the formation of empty and boron-filled octahedral Ir{sub 6} clusters. According to the result of tight-binding electronic structure calculations, Ir-B and Ir-Zr interactions are mainly responsible for the structural stability of the phase. According to COHP bonding analysis, the strongest bonding occurs for the Ir-B contacts, and the Ir-Ir bonding within the empty clusters is two times stronger than that in the BIr{sub 6} octahedra. - Graphical abstract: Zr{sub 2}Ir{sub 6}B crystallizes with an eightfold superstructure of the already reported simple cubic perovskite ZrIr{sub 3}B{sub x}. According to the result of tight-binding electronic structure calculations, Ir-B and Ir-Zr interactions are mainly responsible for its structural stability, and the Ir-Ir bonding within the empty Ir{sub 6} clusters is two times stronger than that in the BIr{sub 6} octahedra.

  8. Reducing carbon dioxide to products

    SciTech Connect

    Cole, Emily Barton; Sivasankar, Narayanappa; Parajuli, Rishi; Keets, Kate A

    2014-09-30

    A method reducing carbon dioxide to one or more products may include steps (A) to (C). Step (A) may bubble said carbon dioxide into a solution of an electrolyte and a catalyst in a divided electrochemical cell. The divided electrochemical cell may include an anode in a first cell compartment and a cathode in a second cell compartment. The cathode may reduce said carbon dioxide into said products. Step (B) may adjust one or more of (a) a cathode material, (b) a surface morphology of said cathode, (c) said electrolyte, (d) a manner in which said carbon dioxide is bubbled, (e), a pH level of said solution, and (f) an electrical potential of said divided electrochemical cell, to vary at least one of (i) which of said products is produced and (ii) a faradaic yield of said products. Step (C) may separate said products from said solution.

  9. Solution Leaching

    NASA Astrophysics Data System (ADS)

    Chun, Tiejun; Zhu, Deqing; Pan, Jian; He, Zhen

    2014-06-01

    Recovery of alumina from magnetic separation tailings of red mud has been investigated by Na2CO3 solution leaching. X-ray diffraction (XRD) results show that most of the alumina is present as 12CaO·7Al2O3 and CaO·Al2O3 in the magnetic separation tailings. The shrinking core model was employed to describe the leaching kinetics. The results show that the calculated activation energy of 8.31 kJ/mol is characteristic for an internal diffusion-controlled process. The kinetic equation can be used to describe the leaching process. The effects of Na2CO3 concentration, liquid-to-solid ratio, and particle size on recovery of Al2O3 were examined.

  10. All-in-one bioprobe devised with hierarchical-ordered magnetic NiCo2O4 superstructure for ultrasensitive dual-readout immunosensor for logic diagnosis of tumor marker.

    PubMed

    Dai, Hong; Gong, Lingshan; Zhang, Shupei; Xu, Guifang; Li, Yilin; Hong, Zhensheng; Lin, Yanyu

    2016-03-15

    A new enzyme-free all-in-one bioprobe, consisted of hematin decorated magnetic NiCo2O4 superstructure (ATS-MNS-Hb), was designed for ultrasensitive photoelectrochemical and electrochemical dual-readout immunosensing of carcinoembryonic antigen (CEA) on carbon nanohorns (CNH) support. Herein, the MNS, possessed hierarchical-ordered structure, good porosity and magnetism, acted as nanocarrier to absorb abundant Hb molecular after functionalization, providing a convenient collection means by magnetic control as well as enhanced dual-readout sensing performances. CNH superstructures were employed as support to immobilize abounding captured antibodies, and then as-designed dual mode bioprobe, covalent binding with secondary antibody of CEA, was introduced for ultrasensitive detection of CEA by sandwich immunosensing. Photoelectrochemical response originated from plentiful hematin molecular, a excellent photosensitizer with good visible light harvesting efficiency, absorbed by functionalized porous MNS. The resultant concentration dependant linear calibration range was from 10 fg/mL to 1 ng/mL with ultralow detection limit of 10 fg/mL. For electrochemical process, catalase-like property of MNS was validated, moreover, MNS-Hb hybrid exhibited much higher mimic enzyme catalytic activity and evidently amplified electrocatalytic signal, performing a wide dynamic linear range from 1 ng/mL to 40 ng/mL with low detection limit of 1 ng/mL. Additionally, due to the improved accuracy of dual signals detection, the exact diagnoses of serum samples were gotten by operating resulting dual signals with AND logic system. This work demonstrated the promising application of MNS in developing ultrasensitive, cost-effective and environment friendly dual-readout immunosensor and accurate diagnoses strategy for tumor markers. PMID:26528807

  11. Life's Solution

    NASA Astrophysics Data System (ADS)

    Morris, Simon Conway

    2003-09-01

    Life's Solution builds a persuasive case for the predictability of evolutionary outcomes. The case rests on a remarkable compilation of examples of convergent evolution, in which two or more lineages have independently evolved similar structures and functions. The examples range from the aerodynamics of hovering moths and hummingbirds to the use of silk by spiders and some insects to capture prey. Going against the grain of Darwinian orthodoxy, this book is a must read for anyone grappling with the meaning of evolution and our place in the Universe. Simon Conway Morris is the Ad Hominen Professor in the Earth Science Department at the University of Cambridge and a Fellow of St. John's College and the Royal Society. His research focuses on the study of constraints on evolution, and the historical processes that lead to the emergence of complexity, especially with respect to the construction of the major animal body parts in the Cambrian explosion. Previous books include The Crucible of Creation (Getty Center for Education in the Arts, 1999) and co-author of Solnhofen (Cambridge, 1990). Hb ISBN (2003) 0-521-82704-3

  12. Life's Solution

    NASA Astrophysics Data System (ADS)

    Morris, Simon Conway

    2004-11-01

    Life's Solution builds a persuasive case for the predictability of evolutionary outcomes. The case rests on a remarkable compilation of examples of convergent evolution, in which two or more lineages have independently evolved similar structures and functions. The examples range from the aerodynamics of hovering moths and hummingbirds to the use of silk by spiders and some insects to capture prey. Going against the grain of Darwinian orthodoxy, this book is a must read for anyone grappling with the meaning of evolution and our place in the Universe. Simon Conway Morris is the Ad Hominen Professor in the Earth Science Department at the University of Cambridge and a Fellow of St. John's College and the Royal Society. His research focuses on the study of constraints on evolution, and the historical processes that lead to the emergence of complexity, especially with respect to the construction of the major animal body parts in the Cambrian explosion. Previous books include The Crucible of Creation (Getty Center for Education in the Arts, 1999) and co-author of Solnhofen (Cambridge, 1990). Hb ISBN (2003) 0-521-82704-3

  13. Alloy solution hardening with solute pairs

    DOEpatents

    Mitchell, John W.

    1976-08-24

    Solution hardened alloys are formed by using at least two solutes which form associated solute pairs in the solvent metal lattice. Copper containing equal atomic percentages of aluminum and palladium is an example.

  14. ELECTROLYTIC REDUCTION OF NITRIC ACID SOLUTIONS

    DOEpatents

    Alter, H.W.; Barney, D.L.

    1958-09-30

    A process is presented for the treatment of radioactivc waste nitric acid solutions. The nitric acid solution is neutralized with an alkali metal hydroxide in an amount sufficient to precipitate insoluble hydroxides, and after separation of the precipitate the solution is electrolyzed to convert the alkali nitrate formed, to alkali hydroxide, gaseous ammonla and oxygen. The solution is then reusable after reducing the volume by evaporating the water and dissolved ammonia.

  15. New Solutions to Reduce Discard of Kidneys Donated for Transplantation.

    PubMed

    Reese, Peter P; Harhay, Meera N; Abt, Peter L; Levine, Matthew H; Halpern, Scott D

    2016-04-01

    Kidney transplantation is a cost-saving treatment that extends the lives of patients with ESRD. Unfortunately, the kidney transplant waiting list has ballooned to over 100,000 Americans. Across large areas of the United States, many kidney transplant candidates spend over 5 years waiting and often die before undergoing transplantation. However, more than 2500 kidneys (>17% of the total recovered from deceased donors) were discarded in 2013, despite evidence that many of these kidneys would provide a survival benefit to wait-listed patients. Transplant leaders have focused attention on transplant center report cards as a likely cause for this discard problem, although that focus is too narrow. In this review, we examine the risks associated with accepting various categories of donated kidneys, including discarded kidneys, compared with the risk of remaining on dialysis. With the goal of improving access to kidney transplant, we describe feasible proposals to increase acceptance of currently discarded organs. PMID:26369343

  16. A pseudo-tetragonal tungsten bronze superstructure: a combined solution of the crystal structure of K6.4(Nb,Ta)(36.3)O94 with advanced transmission electron microscopy and neutron diffraction.

    PubMed

    Paria Sena, Robert; Babaryk, Artem A; Khainakov, Sergiy; Garcia-Granda, Santiago; Slobodyanik, Nikolay S; Van Tendeloo, Gustaaf; Abakumov, Artem M; Hadermann, Joke

    2016-01-21

    The crystal structure of the K6.4Nb28.2Ta8.1O94 pseudo-tetragonal tungsten bronze-type oxide was determined using a combination of X-ray powder diffraction, neutron diffraction and transmission electron microscopy techniques, including electron diffraction, high angle annular dark field scanning transmission electron microscopy (HAADF-STEM), annular bright field STEM (ABF-STEM) and energy-dispersive X-ray compositional mapping (STEM-EDX). The compound crystallizes in the space group Pbam with unit cell parameters a = 37.468(9) Å, b = 12.493(3) Å, c = 3.95333(15) Å. The structure consists of corner sharing (Nb,Ta)O6 octahedra forming trigonal, tetragonal and pentagonal tunnels. All tetragonal tunnels are occupied by K(+) ions, while 1/3 of the pentagonal tunnels are preferentially occupied by Nb(5+)/Ta(5+) and 2/3 are occupied by K(+) in a regular pattern. A fractional substitution of K(+) in the pentagonal tunnels by Nb(5+)/Ta(5+) is suggested by the analysis of the HAADF-STEM images. In contrast to similar structures, such as K2Nb8O21, also parts of the trigonal tunnels are fractionally occupied by K(+) cations. PMID:26646168

  17. Crystal structure and Ce valence variation in the solid solution CeRh3 - xPdxB0.5

    NASA Astrophysics Data System (ADS)

    Zeiringer, I.; Sereni, J. G.; Berisso, M. G.; Yubuta, K.; Rogl, P.; Grytsiv, A.; Bauer, E.

    2014-03-01

    Crystal structure and physical properties have been studied in the solid solution CeRh3 - xPdxB0.5 (x = 0, 0.5, 1.2, 1.5, 1.7, 2.5, 3) in as-cast state by x-ray powder diffraction and scanning and high-resolution electron microscopy, as well as by low-temperature measurements of the magnetic susceptibility and specific heat. X-ray powder patterns of the alloys were indexed on the basis of a cubic primitive AuCu3 lattice throughout the entire solution showing a monotonous increase in three regimes. For 0 ≦̸ x ≦̸ 1.5, the volume increase corresponds merely to the substitution of Rh by Pd atoms, the sizes of which are rather close. In this regime the tetravalent character of cerium is unaffected. For x > 1.5, the lattice expansion becomes enhanced and is thus attributed to a gradual valence change of the Ce atoms (an intermediate valence regime). Finally, for x > 2.4, the system shows a predominant trivalent behavior. In this region, the specific heat coefficient reaches a value of 4.4 J mol-1 K2, two orders of magnitude larger than that in the Rh-rich border. Selected area electron diffraction patterns of the CeRh3 - x Pd x B0.5 compounds revealed the appearance of ½ ½ ½-type superstructures and satellite reflections with respect to the parent AuCu3 structure. Whereas the ½ ½ ½-type superstructure is confined to the Rh-rich part of the solid solution, satellite reflections are observed throughout the solid solution and hint towards the existence of a domain structure enclosed by anti-phase boundaries.

  18. Peritoneal dialysis solution and nutrition.

    PubMed

    Verger, Christian

    2012-01-01

    20-70% of peritoneal dialysis patients have some signs of malnutrition. Anorexia, protein and amino acid losses in dialysate, advanced age of elderly patients, inflammation and cardiac failure are among the main causes. Modern dialysis solutions aim to reduce these causes, but none of them is without side effects: glucose is relatively safe and brings additional energy but induces anorexia and lipid abnormalities, amino acids compensate dialysate losses but may increase uremia and acidosis, icodextrin helps control hyperhydration and chronic heart failure and minimizes glucose side effects, but may sometimes cause inflammation, and poly chamber bags allow the replacement of lactate by bicarbonate and are more biocompatible, decrease GDP, induce less inflammation and have a better effect on nutritional status. However, it appears that the management of nutrition with the different solutions available nowadays necessitates various combinations of solutions adapted to different patient profiles and there is not actually a single universal solution to minimize malnutrition in peritoneal dialysis patients. PMID:22652708

  19. Method for selectively reducing plutonium values by a photochemical process

    DOEpatents

    Friedman, Horace A.; Toth, Louis M.; Bell, Jimmy T.

    1978-01-01

    The rate of reduction of Pu(IV) to Pu(III) in nitric acid solution containing a reducing agent is enhanced by exposing the solution to 200-500 nm electromagnetic radiation. Pu values are recovered from an organic extractant solution containing Pu(IV) values and U(VI) values by the method of contacting the extractant solution with an aqueous nitric acid solution in the presence of a reducing agent and exposing the aqueous solution to electromagnetic radiation having a wavelength of 200-500 nm. Under these conditions, Pu values preferentially distribute to the aqueous phase and U values preferentially distribute to the organic phase.

  20. Microbial methods of reducing technetium

    DOEpatents

    Wildung, Raymond E [Richland, WA; Garland, Thomas R [Greybull, WY; Gorby, Yuri A [Richland, WA; Hess, Nancy J [Benton City, WA; Li, Shu-Mei W [Richland, WA; Plymale, Andrew E [Richland, WA

    2001-01-01

    The present invention is directed toward a method for microbial reduction of a technetium compound to form other compounds of value in medical imaging. The technetium compound is combined in a mixture with non-growing microbial cells which contain a technetium-reducing enzyme system, a stabilizing agent and an electron donor in a saline solution under anaerobic conditions. The mixture is substantially free of an inorganic technetium reducing agent and its reduction products. The resulting product is Tc of lower oxidation states, the form of which can be partially controlled by the stabilizing agent. It has been discovered that the microorganisms Shewanella alga, strain Bry and Shewanelia putrifacians, strain CN-32 contain the necessary enzyme systems for technetium reduction and can form both mono nuclear and polynuclear reduced Tc species depending on the stabilizing agent.

  1. Method and apparatus for reducing solvent luminescence background emissions

    DOEpatents

    Affleck, Rhett L.; Ambrose, W. Patrick; Demas, James N.; Goodwin, Peter M.; Johnson, Mitchell E.; Keller, Richard A.; Petty, Jeffrey T.; Schecker, Jay A.; Wu, Ming

    1998-01-01

    The detectability of luminescent molecules in solution is enhanced by reducing the background luminescence due to impurity species also present in the solution. A light source that illuminates the solution acts to photolyze the impurities so that the impurities do not luminesce in the fluorescence band of the molecule of interest. Molecules of interest may be carried through the photolysis region in the solution or may be introduced into the solution after the photolysis region.

  2. Method and apparatus for reducing solvent luminescence background emissions

    DOEpatents

    Affleck, R.L.; Ambrose, W.P.; Demas, J.N.; Goodwin, P.M.; Johnson, M.E.; Keller, R.A.; Petty, J.T.; Schecker, J.A.; Wu, M.

    1998-10-27

    The detectability of luminescent molecules in solution is enhanced by reducing the background luminescence due to impurity species also present in the solution. A light source that illuminates the solution acts to photolyze the impurities so that the impurities do not luminesce in the fluorescence band of the molecule of interest. Molecules of interest may be carried through the photolysis region in the solution or may be introduced into the solution after the photolysis region. 6 figs.

  3. Thermodynamics of Dilute Solutions.

    ERIC Educational Resources Information Center

    Jancso, Gabor; Fenby, David V.

    1983-01-01

    Discusses principles and definitions related to the thermodynamics of dilute solutions. Topics considered include dilute solution, Gibbs-Duhem equation, reference systems (pure gases and gaseous mixtures, liquid mixtures, dilute solutions), real dilute solutions (focusing on solute and solvent), terminology, standard states, and reference systems.…

  4. PROCESSES OF RECLAIMING URANIUM FROM SOLUTIONS

    DOEpatents

    Zumwalt, L.R.

    1959-02-10

    A process is described for reclaiming residual enriched uranium from calutron wash solutions containing Fe, Cr, Cu, Ni, and Mn as impurities. The solution is adjusted to a pH of between 2 and 4 and is contacted with a metallic reducing agent, such as iron or zinc, in order to reduce the copper to metal and thereby remove it from the solution. At the same time the uranium present is reduced to the uranous state The solution is then contacted with a precipitate of zinc hydroxide or barium carbonate in order to precipitate and carry uranium, iron, and chromium away from the nickel and manganese ions in the solution. The uranium is then recovered fronm this precipitate.

  5. The Paperless Solution

    NASA Technical Reports Server (NTRS)

    2001-01-01

    REI Systems, Inc. developed a software solution that uses the Internet to eliminate the paperwork typically required to document and manage complex business processes. The data management solution, called Electronic Handbooks (EHBs), is presently used for the entire SBIR program processes at NASA. The EHB-based system is ideal for programs and projects whose users are geographically distributed and are involved in complex management processes and procedures. EHBs provide flexible access control and increased communications while maintaining security for systems of all sizes. Through Internet Protocol- based access, user authentication and user-based access restrictions, role-based access control, and encryption/decryption, EHBs provide the level of security required for confidential data transfer. EHBs contain electronic forms and menus, which can be used in real time to execute the described processes. EHBs use standard word processors that generate ASCII HTML code to set up electronic forms that are viewed within a web browser. EHBs require no end-user software distribution, significantly reducing operating costs. Each interactive handbook simulates a hard-copy version containing chapters with descriptions of participants' roles in the online process.

  6. Cosmological string solutions by dimensional reduction

    SciTech Connect

    Behrndt, K.; Foerste, S.

    1993-12-01

    We obtain cosmological four dimensional solutions of the low energy effective string theory by reducing a five dimensional black hole, and black hole-de Sitter solution of the Einstein gravity down to four dimensions. The appearance of a cosmological constant in the five dimensional Einstein-Hilbert produces a special dilaton potential in the four dimensional effective string action. Cosmological scenarios implement by our solutions are discussed.

  7. Robinson-Trautman solution with scalar hair

    NASA Astrophysics Data System (ADS)

    Tahamtan, T.; Svítek, O.

    2015-05-01

    The explicit Robinson-Trautman solution with a minimally coupled free scalar field is derived and analyzed. It is shown that this solution contains curvature singularity, which is initially naked but later enveloped by the horizon. We use the quasilocal horizon definition and prove its existence in later retarded times using sub- and supersolution method combined with growth estimates. We show that the solution is generally of algebraic type II but reduces to type D in spherical symmetry.

  8. Silicon oxidation in fluoride solutions

    NASA Technical Reports Server (NTRS)

    Sancier, K. M.; Kapur, V.

    1980-01-01

    Silicon is produced in a NaF, Na2SiF6, and Na matrix when SiF4 is reduced by metallic sodium. Hydrogen is evolved during acid leaching to separate the silicon from the accompanying reaction products, NaF and Na2SiF6. The hydrogen evolution reaction was studied under conditions simulating leaching conditions by making suspensions of the dry silicon powder in aqueous fluoride solutions. The mechanism for the hydrogen evolution is discussed in terms of spontaneous oxidation of silicon resulting from the cooperative effects of (1) elemental sodium in the silicon that reacts with water to remove a protective silica layer, leaving clean reactive silicon, and (2) fluoride in solution that complexes with the oxidized silicon in solution and retards formation of a protective hydrous oxide gel.

  9. Processing Solutions for Big Data in Astronomy

    NASA Astrophysics Data System (ADS)

    Fillatre, L.; Lepiller, D.

    2016-09-01

    This paper gives a simple introduction to processing solutions applied to massive amounts of data. It proposes a general presentation of the Big Data paradigm. The Hadoop framework, which is considered as the pioneering processing solution for Big Data, is described together with YARN, the integrated Hadoop tool for resource allocation. This paper also presents the main tools for the management of both the storage (NoSQL solutions) and computing capacities (MapReduce parallel processing schema) of a cluster of machines. Finally, more recent processing solutions like Spark are discussed. Big Data frameworks are now able to run complex applications while keeping the programming simple and greatly improving the computing speed.

  10. Ionic solutes impact collagen scaffold bioactivity.

    PubMed

    Pawelec, K M; Husmann, A; Wardale, R J; Best, S M; Cameron, R E

    2015-02-01

    The structure of ice-templated collagen scaffolds is sensitive to many factors. By adding 0.5 wt% of sodium chloride or sucrose to collagen slurries, scaffold structure could be tuned through changes in ice growth kinetics and interactions of the solute and collagen. With ionic solutes (sodium chloride) the entanglements of the collagen molecule decreased, leading to fibrous scaffolds with increased pore size and decreased attachment of chondrocytes. With non-ionic solutes (sucrose) ice growth was slowed, leading to significantly reduced pore size and up-regulated cell attachment. This highlights the large changes in structure and biological function stimulated by solutes in ice-templating systems. PMID:25649518

  11. Reduce HIV Risk

    MedlinePlus

    ... incidence could be reduced if people changed their sexual behaviors. Our research has demonstrated remarkable success in reducing HIV risk-associated sexual behaviors among African American adolescents and adults." Spring 2008 ...

  12. Supergravity solutions without triholomorphic U(1) isometries

    SciTech Connect

    Ghezelbash, A. M.

    2008-12-15

    We investigate the construction of five-dimensional supergravity solutions that do not have any triholomorphic U(1) isometries. We construct a class of solutions that in various limits of parameters reduces to many of previously constructed five-dimensional supergravity solutions based on both hyper-Kaehler base spaces that can be put into a Gibbons-Hawking form and hyper-Kaehler base spaces that cannot be put into a Gibbons-Hawking form. We find a new solution which is over triaxial Bianchi type IX Einstein-hyper-Kaehler base space with no triholomorphic U(1) symmetry. One special case of this solution corresponds to a five-dimensional solution based on Eguchi-Hanson type II geometry.

  13. Contact Lens Solution Toxicity

    MedlinePlus

    ... rash and rashes clinical tools newsletter | contact Share | Contact Lens Solution Toxicity Information for adults A A A This image shows a reaction to contact lens solution. The prominent blood vessels and redness ...

  14. Spectroscopic studies of solutes in aqueous solution.

    PubMed

    Chai, Bing-hua; Zheng, Jian-ming; Zhao, Qing; Pollack, Gerald H

    2008-03-20

    Absorption and fluorescence characteristics of aqueous solutions of salts, sugars, and amino acids were studied using UV-vis spectroscopy and spectrofluorometry. Motivation stemmed from unanticipated absorption spectral and fluorescence features of the "exclusion zone" seen adjacent to various hydrophilic surfaces. Those features implied a structure distinct from that of bulk water (Adv. Colloid Interface Sci. 2006, 127, 19). Absorption peaks at approximately 270 nm similar to those observed in the exclusion zone were seen in solutions of the following substances: salts, Nafion 117 solution/film, l-lysine, d-alanine, d-glucose and sucrose. To determine the fate of the absorbed energy, we studied the fluorescence properties of these solutions. The salts showed fluorescence emission around 480-490 nm under different excitation wavelengths. The fluorescence intensity of LiCl was higher than NaCl, which was in turn higher than KCl-the same ordering as the absorption intensities. Fluorescence of Nafion 117 solution/film, l-lysine, d-alanine, d-glucose and sucrose were observed as well, with multiple excitation wavelengths. Hence, at least some of the absorbed energy is released as fluorescence. The results show features closely similar to those observed in the exclusion zone, implying that the aqueous region around the solutes resembles the aqueous zone adjacent to hydrophilic surfaces. Both may be more extensively ordered than previously thought. PMID:18298105

  15. Static and stationary multiple soliton solutions to the Einstein equations

    SciTech Connect

    Letelier, P.S.

    1985-03-01

    The application of the Belinsky--Zakharov solution-generating technique, i.e., the inverse scattering method, to generate stationary axially symmetric solutions to the vacuum Einstein equations is reduced to a single quadrature when the seed solution is diagonal. The possibility of having real odd-number soliton solutions is investigated. These solutions represent solitonic perturbations of Euclidean metrics. The possibility of using instantons as seed solutions is also investigated. The one- and two-soliton solutions generated from a diagonal seed solution are studied. As an application, a unified derivation of some well-known static solutions, like the Schwarzschild metric and the Chazy--Curzon metric, as well as other new metrics is presented. By using these metrics as seed solutions, some known stationary solutions, like the Kerr-NUT metric, the double Kerr metric, and the rotating Weyl C-metric, as well as other new metrics are also derived in a unified way.

  16. The electromagnetic spike solutions

    NASA Astrophysics Data System (ADS)

    Nungesser, Ernesto; Lim, Woei Chet

    2013-12-01

    The aim of this paper is to use the existing relation between polarized electromagnetic Gowdy spacetimes and vacuum Gowdy spacetimes to find explicit solutions for electromagnetic spikes by a procedure which has been developed by one of the authors for gravitational spikes. We present new inhomogeneous solutions which we call the EME and MEM electromagnetic spike solutions.

  17. Reducing pharmacy costs through improved utilization.

    PubMed

    Bates, Cinda; Richards, Barton S

    2013-06-01

    Strategies Trinity Regional Health System in Rock Island, III., used to reduce pharmacy expenses included: Leveraging benchmarking information to identify opportunities for cost savings. Implementing change management techniques, bolstered by well-presented and coherent data, to promote acceptance of change. Forming a multidisciplinary team of clinical and financial leaders to address quality, outcomes, and cost issues and collaborate on solutions. PMID:23795386

  18. Reducing urinary tract infections in catheterised patients.

    PubMed

    Howe, Pam; Adams, John

    2015-01-20

    Urinary tract infections in catheterised patients continue to present a challenge in reducing healthcare-associated infection. In this article, an infection prevention and control team in one NHS trust reports on using audit results to focus attention on measures to reduce bacterial infections. Educational initiatives have an important role in reducing infection, but there is no single solution to the problem. Practice can be improved using a multi-targeted approach, peer review and clinical audit to allow for shared learning and experiences. These, along with informal education in the clinical area and more formal classroom lectures, can ultimately lead to improved patient outcomes. PMID:25585767

  19. Vanadium Nitrogenase Reduces CO*

    PubMed Central

    Lee, Chi Chung; Hu, Yilin; Ribbe, Markus W.

    2011-01-01

    Vanadium nitrogenase not only reduces dinitrogen to ammonia but also reduces carbon monoxide to ethylene, ethane, and propane. The parallelism between the two reactions suggests a potential link in mechanism and evolution between the carbon and nitrogen cycles on Earth. PMID:20689010

  20. Vanadium nitrogenase reduces CO.

    PubMed

    Lee, Chi Chung; Hu, Yilin; Ribbe, Markus W

    2010-08-01

    Vanadium nitrogenase not only reduces dinitrogen to ammonia but also reduces carbon monoxide to ethylene, ethane, and propane. The parallelism between the two reactions suggests a potential link in mechanism and evolution between the carbon and nitrogen cycles on Earth. PMID:20689010

  1. Reducible oxide based catalysts

    DOEpatents

    Thompson, Levi T.; Kim, Chang Hwan; Bej, Shyamal K.

    2010-04-06

    A catalyst is disclosed herein. The catalyst includes a reducible oxide support and at least one noble metal fixed on the reducible oxide support. The noble metal(s) is loaded on the support at a substantially constant temperature and pH.

  2. Reducing Teacher Incompetence.

    ERIC Educational Resources Information Center

    Rich, John Martin

    1988-01-01

    Suggests how administrators may reduce teacher incompetence. Teacher incompetence can be reduced if administrators fully understand and undertake appropriate preventive and remedial measures. Two sections comprise this article. First, a taxonomy of teacher incompetence reveals the magnitude of the problem. Second, preventive and remedial measures…

  3. Strong shock implosion, approximate solution

    NASA Astrophysics Data System (ADS)

    Fujimoto, Y.; Mishkin, E. A.; Alejaldre, C.

    1983-01-01

    The self-similar, center-bound motion of a strong spherical, or cylindrical, shock wave moving through an ideal gas with a constant, γ= cp/ cv, is considered and a linearized, approximate solution is derived. An X, Y phase plane of the self-similar solution is defined and the representative curved of the system behind the shock front is replaced by a straight line connecting the mappings of the shock front with that of its tail. The reduced pressure P(ξ), density R(ξ) and velocity U1(ξ) are found in closed, quite accurate, form. Comparison with numerically obtained results, for γ= {5}/{3} and γ= {7}/{5}, is shown.

  4. Nitric acid recovery from waste solutions

    DOEpatents

    Wilson, A. S.

    1959-04-14

    The recovery of nitric acid from aqueous nitrate solutions containing fission products as impurities is described. It is desirable to subject such solutions to concentration by evaporation since nitric acid is regenerated thereby. A difficulty, however, is that the highly radioactive fission product ruthenium is volatilized together with the nitric acid. It has been found that by adding nitrous acid, ruthenium volatilization is suppressed and reduced to a negligible degree so that the distillate obtained is practically free of ruthenium.

  5. Solution deposition assembly

    SciTech Connect

    Roussillon, Yann; Scholz, Jeremy H; Shelton, Addison; Green, Geoff T; Utthachoo, Piyaphant

    2014-01-21

    Methods and devices are provided for improved deposition systems. In one embodiment of the present invention, a deposition system is provided for use with a solution and a substrate. The system comprises of a solution deposition apparatus; at least one heating chamber, at least one assembly for holding a solution over the substrate; and a substrate curling apparatus for curling at least one edge of the substrate to define a zone capable of containing a volume of the solution over the substrate. In another embodiment of the present invention, a deposition system for use with a substrate, the system comprising a solution deposition apparatus; at heating chamber; and at least assembly for holding solution over the substrate to allow for a depth of at least about 0.5 microns to 10 mm.

  6. Reducing Childhood Obesity

    MedlinePlus

    ... Bar Home Current Issue Past Issues Reducing Childhood Obesity Past Issues / Summer 2007 Table of Contents For ... Ga. were the first three We Can! cities. Obesity Research: A New Approach The percentage of children ...

  7. Reduced Extended MHD

    NASA Astrophysics Data System (ADS)

    Morrison, P. J.; Abdelhamid, H. M.; Grasso, D.; Hazeltine, R. D.; Lingam, M.; Tassi, E.

    2015-11-01

    Over the years various reduced fluid models have been obtained for modeling plasmas, with the goal of capturing important physics while maintaining computability. Such models have included the physics contained in various generalizations of Ohm's law, including Hall drift and electron inertia. In a recent publication it was shown that full 3D extended MHD is a Hamiltonian system by finding its noncanonical Poisson bracket. Subsequently, this bracket was shown to be derivable from that for Hall MHD by a series of remarkable transformations, which greatly simplifies the proof of the Jacobi identity and allows one to immediately obtain generalizations of the helicity and cross helicity. In this poster we use this structure to obtain exact reduced fluid models with the effects of full two-fluid theory. Results of numerical computations of collisionless reconnection using an exact reduced 4-field model will be presented and analytical comparisons of mode structure of previous reduced models will be made.

  8. Reducing Teacher Stress.

    ERIC Educational Resources Information Center

    Docking, R. A.; Docking, E.

    1984-01-01

    Reports on a case study of inservice training conducted to enhance the teacher/student relationship and reduce teacher anxiety. Found significant improvements in attitudes, classroom management activities, and lower anxiety among teachers. (MD)

  9. Reduced-order preconditioning for bidomain simulations.

    PubMed

    Deo, Makarand; Bauer, Steffen; Plank, Gernot; Vigmond, Edward

    2007-05-01

    Simulations of the bidomain equations involve solving large, sparse, linear systems of the form Ax = b. Being an initial value problems, it is solved at every time step. Therefore, efficient solvers are essential to keep simulations tractable. Iterative solvers, especially the preconditioned conjugate gradient (PCG) method, are attractive since memory demands are minimized compared to direct methods, albeit at the cost of solution speed. However, a proper preconditioner can drastically speed up the solution process by reducing the number of iterations. In this paper, a novel preconditioner for the PCG method based on system order reduction using the Arnoldi method (A-PCG) is proposed. Large order systems, generated during cardiac bidomain simulations employing a finite element method formulation, are solved with the A-PCG method. Its performance is compared with incomplete LU (ILU) preconditioning. Results indicate that the A-PCG estimates an approximate solution considerably faster than the ILU, often within a single iteration. To reduce the computational demands in terms of memory and run time, the use of a cascaded preconditioner was suggested. The A-PCG was applied to quickly obtain an approximate solution, and subsequently a cheap iterative method such as successive overrelaxation (SOR) is applied to further refine the solution to arrive at a desired accuracy. The memory requirements are less than those of direct LU but more than ILU method. The proposed scheme is shown to yield significant speedups when solving time evolving systems. PMID:17518292

  10. Treating Fibrous Insulation to Reduce Thermal Conductivity

    NASA Technical Reports Server (NTRS)

    Zinn, Alfred; Tarkanian, Ryan

    2009-01-01

    A chemical treatment reduces the convective and radiative contributions to the effective thermal conductivity of porous fibrous thermal-insulation tile. The net effect of the treatment is to coat the surfaces of fibers with a mixture of transition-metal oxides (TMOs) without filling the pores. The TMO coats reduce the cross-sectional areas available for convection while absorbing and scattering thermal radiation in the pores, thereby rendering the tile largely opaque to thermal radiation. The treatment involves a sol-gel process: A solution containing a mixture of transition-metal-oxide-precursor salts plus a gelling agent (e.g., tetraethylorthosilicate) is partially cured, then, before it visibly gels, is used to impregnate the tile. The solution in the tile is gelled, then dried, and then the tile is fired to convert the precursor salts to the desired mixed TMO phases. The amounts of the various TMOs ultimately incorporated into the tile can be tailored via the concentrations of salts in the solution, and the impregnation depth can be tailored via the viscosity of the solution and/or the volume of the solution relative to that of the tile. The amounts of the TMOs determine the absorption and scattering spectra.

  11. SEPARATION OF RUTHENIUM FROM AQUEOUS SOLUTIONS

    DOEpatents

    Callis, C.F.; Moore, R.L.

    1959-09-01

    >The separation of ruthenium from aqueous solutions containing uranium plutonium, ruthenium, and fission products is described. The separation is accomplished by providing a nitric acid solution of plutonium, uranium, ruthenium, and fission products, oxidizing plutonium to the hexavalent state with sodium dichromate, contacting the solution with a water-immiscible organic solvent, such as hexone, to extract plutonyl, uranyl, ruthenium, and fission products, reducing with sodium ferrite the plutonyl in the solvent phase to trivalent plutonium, reextracting from the solvent phase the trivalent plutonium, ruthenium, and some fission products with an aqueous solution containing a salting out agent, introducing ozone into the aqueous acid solution to oxidize plutonium to the hexavalent state and ruthenium to ruthenium tetraoxide, and volatizing off the ruthenium tetraoxide.

  12. Exact solution to fractional logistic equation

    NASA Astrophysics Data System (ADS)

    West, Bruce J.

    2015-07-01

    The logistic equation is one of the most familiar nonlinear differential equations in the biological and social sciences. Herein we provide an exact solution to an extension of this equation to incorporate memory through the use of fractional derivatives in time. The solution to the fractional logistic equation (FLE) is obtained using the Carleman embedding technique that allows the nonlinear equation to be replaced by an infinite-order set of linear equations, which we then solve exactly. The formal series expansion for the initial value solution of the FLE is shown to be expressed in terms of a series of weighted Mittag-Leffler functions that reduces to the well known analytic solution in the limit where the fractional index for the derivative approaches unity. The numerical integration to the FLE provides an excellent fit to the analytic solution. We propose this approach as a general technique for solving a class of nonlinear fractional differential equations.

  13. Twisting algebraically special solutions in five dimensions

    NASA Astrophysics Data System (ADS)

    Bernardi de Freitas, Gabriel; Godazgar, Mahdi; Reall, Harvey S.

    2016-05-01

    We determine the general form of the solutions of the five-dimensional vacuum Einstein equations with cosmological constant for which (i) the Weyl tensor is everywhere type II or more special in the null alignment classification of Coley et al, and (ii) the 3 × 3 matrix encoding the expansion, shear and twist of the aligned null direction has rank 2. The dependence of the solution on two coordinates is determined explicitly, so the Einstein equation reduces to PDEs in the three remaining coordinates, just as for four-dimensional (4d) algebraically special solutions. The solutions fall into several families. One of these consists of warped products of 4d algebraically special solutions. The others are new.

  14. REDUCED PROTECTIVE CLOTHING DETERMINATIONS

    SciTech Connect

    BROWN, R.L.

    2003-06-13

    This technical basis document defines conditions where reduced protective clothing can be allowed, defines reduced protective clothing, and documents the regulatory review that determines the process is compliant with the Tank Farm Radiological Control Manual (TFRCM) and Title 10, Part 835, of the Code of Federal Regulations (10CFR835). The criteria, standards, and requirements contained in this document apply only to Tank Farm Contractor (TFC) facilities.

  15. Reduced shear power spectrum

    SciTech Connect

    Dodelson, Scott; Shapiro, Charles; White, Martin J.; /UC, Berkeley, Astron. Dept. /UC, Berkeley

    2005-08-01

    Measurements of ellipticities of background galaxies are sensitive to the reduced shear, the cosmic shear divided by (1-{kappa}) where {kappa} is the projected density field. They compute the difference between shear and reduced shear both analytically and with simulations. The difference becomes more important an smaller scales, and will impact cosmological parameter estimation from upcoming experiments. A simple recipe is presented to carry out the required correction.

  16. Topical diclofenac solution.

    PubMed

    Moen, Marit D

    2009-01-01

    Topical diclofenac solution (Pennsaid) is a liquid formulation containing the NSAID diclofenac sodium (1.5% w/w). The solution base contains 45% w/w dimethyl sulfoxide (DMSO) to enhance the absorption of diclofenac through the skin. Topical diclofenac solution is applied directly to the knee for treatment of symptoms associated with osteoarthritis of the knee. In well designed 4- to 12-week trials in patients with primary osteoarthritis of the knee, topical diclofenac solution (40 drops four times daily) was significantly more effective than placebo or vehicle control (carrier solution without diclofenac) for improving Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index pain and physical function, and improving patient global assessment (PGA) and/or patient overall health assessment scores from baseline to the final assessments. Topical diclofenac solution (50 drops three times daily) was as effective as oral diclofenac 150 mg/day for improving WOMAC pain and physical function and PGA scores in a 12-week double-blind study in patients with osteoarthritis of the knee. Topical diclofenac solution was generally well tolerated. The most common treatment-emergent adverse event experienced by topical diclofenac solution recipients was dry skin at the application site. Gastrointestinal adverse events and abnormal laboratory parameters were less common with topical diclofenac solution than with oral diclofenac. PMID:19943711

  17. Mixed oxide solid solutions

    DOEpatents

    Magno, Scott; Wang, Ruiping; Derouane, Eric

    2003-01-01

    The present invention is a mixed oxide solid solution containing a tetravalent and a pentavalent cation that can be used as a support for a metal combustion catalyst. The invention is furthermore a combustion catalyst containing the mixed oxide solid solution and a method of making the mixed oxide solid solution. The tetravalent cation is zirconium(+4), hafnium(+4) or thorium(+4). In one embodiment, the pentavalent cation is tantalum(+5), niobium(+5) or bismuth(+5). Mixed oxide solid solutions of the present invention exhibit enhanced thermal stability, maintaining relatively high surface areas at high temperatures in the presence of water vapor.

  18. Wormholes in Wyman's solution

    NASA Astrophysics Data System (ADS)

    Formiga, J. B.; Almeida, T. S.

    2014-10-01

    The most general solution of the Einstein field equations coupled with a massless scalar field is known as Wyman's solution. This solution is also present in the Brans-Dicke theory and, due to its importance, it has been studied in detail by many authors. However, this solutions has not been studied from the perspective of a possible wormhole. In this paper, we perform a detailed analysis of this issue. It turns out that there is a wormhole. Although we prove that the so-called throat cannot be traversed by human beings, it can be traversed by particles and bodies that can last long enough.

  19. Solutions of the coupled Higgs field equations.

    PubMed

    Talukdar, Benoy; Ghosh, Swapan K; Saha, Aparna; Pal, Debabrata

    2013-07-01

    By an appropriate choice for the phase of the complex nucleonic field and going over to the traveling coordinate, we reduce the coupled Higgs equations to the Hamiltonian form and treat the resulting equation using the dynamical system theory. We present a phase-space analysis of its stable points. The results of our study demonstrate that the equation can support both traveling- and standing-wave solutions. The traveling-wave solution appears in the form of a soliton and resides in the midst of doubly periodic standing-wave solutions. PMID:23944601

  20. Turbulent drag reduction in nonionic surfactant solutions

    NASA Astrophysics Data System (ADS)

    Tamano, Shinji; Itoh, Motoyuki; Kato, Katsuo; Yokota, Kazuhiko

    2010-05-01

    There are only a few studies on the drag-reducing effect of nonionic surfactant solutions which are nontoxic and biodegradable, while many investigations of cationic surfactant solutions have been performed so far. First, the drag-reducing effects of a nonionic surfactant (AROMOX), which mainly consisted of oleyldimethylamineoxide, was investigated by measuring the pressure drop in the pipe flow at solvent Reynolds numbers Re between 1000 and 60 000. Second, we investigated the drag-reducing effect of a nonionic surfactant on the turbulent boundary layer at momentum-thickness Reynolds numbers Reθ from 443 to 814 using two-component laser-Doppler velocimetry and particle image velocimetry systems. At the temperature of nonionic surfactant solutions, T =25 °C, the maximum drag reduction ratio for AROMOX 500 ppm was about 50%, in the boundary layer flow, although the drag reduction ratio was larger than 60% in pipe flow. Turbulence statistics and structures for AROMOX 500 ppm showed the behavior of typical drag-reducing flow such as suppression of turbulence and modification of near-wall vortices, but they were different from those of drag-reducing cationic surfactant solutions, in which bilayered structures of the fluctuating velocity vectors were observed in high activity.

  1. Cromolyn Sodium Nasal Solution

    MedlinePlus

    Cromolyn comes as a solution to use with a special nasal applicator. It usually is inhaled three to six times a day to prevent allergy ... first time, read the instructions provided with the solution. Ask your doctor, pharmacist, or respiratory therapist to ...

  2. Solvent wash solution

    DOEpatents

    Neace, J.C.

    1984-03-13

    A process is claimed for removing diluent degradation products from a solvent extraction solution, which has been used to recover uranium and plutonium from spent nuclear fuel. A wash solution and the solvent extraction solution are combined. The wash solution contains (a) water and (b) up to about, and including, 50 vol % of at least one-polar water-miscible organic solvent based on the total volume of the water and the highly-polar organic solvent. The wash solution also preferably contains at least one inorganic salt. The diluent degradation products dissolve in the highly-polar organic solvent and the organic solvent extraction solvent do not dissolve in the highly-polar organic solvent. The highly-polar organic solvent and the extraction solvent are separated.

  3. Solvent wash solution

    DOEpatents

    Neace, James C.

    1986-01-01

    Process for removing diluent degradation products from a solvent extraction solution, which has been used to recover uranium and plutonium from spent nuclear fuel. A wash solution and the solvent extraction solution are combined. The wash solution contains (a) water and (b) up to about, and including, 50 volume percent of at least one-polar water-miscible organic solvent based on the total volume of the water and the highly-polar organic solvent. The wash solution also preferably contains at least one inorganic salt. The diluent degradation products dissolve in the highly-polar organic solvent and the organic solvent extraction solvent do not dissolve in the highly-polar organic solvent. The highly-polar organic solvent and the extraction solvent are separated.

  4. Tank closure reducing grout

    SciTech Connect

    Caldwell, T.B.

    1997-04-18

    A reducing grout has been developed for closing high level waste tanks at the Savannah River Site in Aiken, South Carolina. The grout has a low redox potential, which minimizes the mobility of Sr{sup 90}, the radionuclide with the highest dose potential after closure. The grout also has a high pH which reduces the solubility of the plutonium isotopes. The grout has a high compressive strength and low permeability, which enhances its ability to limit the migration of contaminants after closure. The grout was designed and tested by Construction Technology Laboratories, Inc. Placement methods were developed by the Savannah River Site personnel.

  5. Reduced Vector Preisach Model

    NASA Technical Reports Server (NTRS)

    Patel, Umesh D.; Torre, Edward Della; Day, John H. (Technical Monitor)

    2002-01-01

    A new vector Preisach model, called the Reduced Vector Preisach model (RVPM), was developed for fast computations. This model, derived from the Simplified Vector Preisach model (SVPM), has individual components that like the SVPM are calculated independently using coupled selection rules for the state vector computation. However, the RVPM does not require the rotational correction. Therefore, it provides a practical alternative for computing the magnetic susceptibility using a differential approach. A vector version, using the framework of the DOK model, is implemented. Simulation results for the reduced vector Preisach model are also presented.

  6. Neutron scattering study of dilute supercritical solutions

    SciTech Connect

    Cochran, H.D.; Wignall, G.D.; Shah, V.M.; Londono, J.D.; Bienkowski, P.R.

    1994-10-01

    Dilute solutions in supercritical solvents exhibit interesting microstructures that are related to their dramatic macroscopic behavior. In typical attractive solutions, solutes are believed to be surrounded by clusters of solvent molecules, and solute molecules are believed to congregate in the vicinity of one another. Repulsive solutions, on the other hand, exhibit a local region of reduced solvent density around the solute with solute-solute congregation. Such microstructures influence solubility, partial molar volume, reaction kinetics, and many other properties. We have undertaken to observe these interesting microstructures directly by neutron scattering experiments on dilute noble gas systems including Ar. The three partial structure factors for such systems and the corresponding pair correlation functions can be determined by using the isotope substitution technique. The systems studied are uniquely suited for our objectives because of the large coherent neutron scattering length of the isotope {sup 36}Ar and because of the accurate potential energy functions that are available for use in molecular simulations and theoretical calculations to be compared with the scattering results. We will describe our experiment, the unique apparatus we have built for it, and the neutron scattering results from our initial allocations of beam time. We will also describe planned scattering experiments to follow those with noble gases, including study of long-chain molecules in supercritical solvents. Such studies will involve hydrocarbon mixtures with and without deuteration to provide contrast.

  7. Demonstrating Reduced Gravity.

    ERIC Educational Resources Information Center

    Pearlman, Howard; And Others

    1996-01-01

    Describes the construction of the Reduced-Gravity Demonstrator, which can be used to illustrate the effects of gravity on a variety of phenomena, including the way fluids flow, flames burn, and mechanical systems behave. Presents experiments, appropriate for classroom use, to demonstrate how the behavior of common physical systems change when…

  8. Demonstrating Reduced Gravity

    NASA Technical Reports Server (NTRS)

    Pearlman, Howard; Stocker, Dennis; Gotti, Daniel; Urban, David; Ross, Howard; Sours, Thomas

    1996-01-01

    A miniature drop tower, Reduced-Gravity Demonstrator is developed to illustrate the effects of gravity on a variety of phenomena including the way fluids flow, flames burn, and mechanical systems (such as pendulum) behave. A schematic and description of the demonstrator and payloads are given, followed by suggestions for how one can build his (her) own.

  9. Reduced Braginskii equations

    SciTech Connect

    Yagi, M.; Horton, W. )

    1994-07-01

    A set of reduced Braginskii equations is derived without assuming flute ordering and the Boussinesq approximation. These model equations conserve the physical energy. It is crucial at finite [beta] that the perpendicular component of Ohm's law be solved to ensure [del][center dot][bold j]=0 for energy conservation.

  10. Reuse, Reduce, Recycle.

    ERIC Educational Resources Information Center

    Briscoe, Georgia

    1991-01-01

    Discussion of recycling paper in law libraries is also applicable to other types of libraries. Results of surveys of law libraries that investigated recycling practices in 1987 and again in 1990 are reported, and suggestions for reducing the amount of paper used and reusing as much as possible are offered. (LRW)

  11. Conduction heat transfer solutions

    SciTech Connect

    VanSant, J.H.

    1980-03-01

    This text is a collection of solutions to a variety of heat conduction problems found in numerous publications, such as textbooks, handbooks, journals, reports, etc. Its purpose is to assemble these solutions into one source that can facilitate the search for a particular problem solution. Generally, it is intended to be a handbook on the subject of heat conduction. This material is useful for engineers, scientists, technologists, and designers of all disciplines, particularly those who design thermal systems or estimate temperatures and heat transfer rates in structures. More than 500 problem solutions and relevant data are tabulated for easy retrieval. There are twelve sections of solutions which correspond with the class of problems found in each. Geometry, state, boundary conditions, and other categories are used to classify the problems. A case number is assigned to each problem for cross-referencing, and also for future reference. Each problem is concisely described by geometry and condition statements, and many times a descriptive sketch is also included. At least one source reference is given so that the user can review the methods used to derive the solutions. Problem solutions are given in the form of equations, graphs, and tables of data, all of which are also identified by problem case numbers and source references.

  12. Aligning parallel arrays to reduce communication

    NASA Technical Reports Server (NTRS)

    Sheffler, Thomas J.; Schreiber, Robert; Gilbert, John R.; Chatterjee, Siddhartha

    1994-01-01

    Axis and stride alignment is an important optimization in compiling data-parallel programs for distributed-memory machines. We previously developed an optimal algorithm for aligning array expressions. Here, we examine alignment for more general program graphs. We show that optimal alignment is NP-complete in this setting, so we study heuristic methods. This paper makes two contributions. First, we show how local graph transformations can reduce the size of the problem significantly without changing the best solution. This allows more complex and effective heuristics to be used. Second, we give a heuristic that can explore the space of possible solutions in a number of ways. We show that some of these strategies can give better solutions than a simple greedy approach proposed earlier. Our algorithms have been implemented; we present experimental results showing their effect on the performance of some example programs running on the CM-5.

  13. Cleaning optimization for reduced chemical usage

    SciTech Connect

    Resnick, P.J.; Simonson, G.C.; Matlock, C.A.; Kelly, M.J.

    1996-11-01

    The use of dilute SC-1 (NH40H:H202:H20) chemistry cleaning processes for particle removal from silicon surfaces has been investigated. Dilute chemistries can be highly effective, especially when high- frequency acoustic energy (megasonics) is applied. The high particle removal efficacy of the dilute chemistry processes presumably arises due to increased double layer effects caused by reduced ionic strength. Dilute chemistry SC- I solutions exhibit somewhat reduced efficacy for removal of certain light organics; however, when dilute SC-1 is used along with other pre-gate cleaning steps (e.g. HF, SC-2, and piranha), then the overall cleaning sequence is quite effective. In addition to providing robust cleaning processes, dilute chemistries also result in significantly lower chemical and rinse water usage. Waste water treatment requirements are also lessened when dilute chemistry cleaning solutions are employed.

  14. Chemistry of soil solutions

    SciTech Connect

    Elprince, A.M.

    1986-01-01

    Designed for advanced undergraduate and graduate students and researchers, this book serves as an introduction to the field of soil chemistry and associated fields such as aquatic chemistry, geochemistry, environmental chemistry, oceanography, and public health. The volume includes discussions on the structure of adsorbed water, adsorption of inorganics, solubility, redox, solute transport, chemical modeling, and sampling and monitoring the soil solution. Important papers on these topics together with editor's comments place each of the carefully chosen papers in the proper context. Because the chemistry of soil solutions requires the knowledge of many aspects of science, introductory information is provided for each topic to cover its history of development, present knowledge, and future prospects.

  15. Efficacy of multipurpose solutions for rigid gas permeable lenses.

    PubMed

    Boost, Maureen; Cho, Pauline; Lai, Sindy

    2006-09-01

    The use of multipurpose solutions for cleaning and disinfecting rigid gas permeable lenses has replaced single purpose solutions, but there are no reports of the efficacy of these multipurpose solutions, or of the effects of storage conditions on their disinfecting capacities. This study investigated activity against four bacterial and two fungal species, and the effects of storage in a refrigerator, at room temperature, at elevated temperature in both dry and humid conditions and with exposure to sunlight. The disinfecting solutions were challenged with the micro-organisms initially upon opening and then at 2-weekly intervals up to 12 weeks after being stored under the different conditions. Solutions were opened daily to simulate use. One solution failed to meet Food and Drug Administration (FDA) criteria to reduce numbers of bacteria by three log dilutions and of fungi by one log dilution. Storage reduced activity of all solutions over the 12-week period, but not below the requirements of the FDA. Storage in the refrigerator tended to reduce disinfecting capacity more quickly. Multipurpose solutions for rigid gas permeable (RGP) lenses lose activity over the 3 months recommended time of use but remain satisfactory for use over this time in the conditions tested. Practitioners need to remind patients to replace their solutions regularly and should advise against storage in the refrigerator. Multipurpose solutions for RGP lenses have simplified cleaning and disinfecting processes and the current formulations have improved disinfecting capacity compared to former disinfecting solutions, which is particularly important for wearers of orthokeratology lenses. PMID:16918771

  16. Leveraging Technology to Reduce Patient Transaction Costs.

    PubMed

    Edlow, Richard C

    2015-01-01

    Medical practices are under significant pressure to provide superior customer service in an environment of declining or flat reimbursement. The solution for many practices involves the integration of a variety of third-party technologies that conveniently interface with one's electronic practice management and medical records systems. Typically, the applications allow the practice to reduce the cost of each patient interaction. Drilling down to quantify the cost of each individual patient interaction helps to determine the practicality of implementation. PMID:26665478

  17. 'Reduced' magnetohydrodynamics and minimum dissipation rates

    NASA Technical Reports Server (NTRS)

    Montgomery, David

    1992-01-01

    It is demonstrated that all solutions of the equations of 'reduced' magnetohydrodynamics approach a uniform-current, zero-flow state for long times, given a constant wall electric field, uniform scalar viscosity and resistivity, and uniform mass density. This state is the state of minimum energy dissipation rate for these boundary conditions. No steady-state turbulence is possible. The result contrasts sharply with results for full three-dimensional magnetohydrodynamics before the reduction occurs.

  18. Reducing the open porosity of pyroboroncarbon articles

    NASA Astrophysics Data System (ADS)

    Martyushov, G. G.; Zakharevich, A. M.; Pichkhidze, S. Ya.; Koshuro, V. A.

    2016-02-01

    It is established that a decrease in the open porosity of pyroboroncarbon, a pyrolytic glassy composite material of interest for manufacturing prosthetic heart valves (PHVs), can be achieved via impregnation of articles with an alcohol solution of 3-aminopropyltriethoxysilane and subsequent thermal treatment. The maximum roughness height and linear size of open pores on the surface of PHV parts made of pyroboroncarbon can additionally be reduced by final mechanical processing of a silicon oxide film formed on the surface.

  19. Advanced integrated solution for MEMS design

    NASA Astrophysics Data System (ADS)

    Liateni, Karim; Moulinier, David; Affour, Bachar; Boutamine, H.; Karam, Jean Michel; Veychard, D.; Courtois, Bernard; Cao, Ariel D.

    1999-03-01

    This paper presents a fully integrated solution for the development of Micro Electro Mechanical Systems which covers component libraries, design tools and designs methodologies which are used in conjunction with conventional design automation tools. This solutio enables system houses in wireless and optical communications and consumers electronics markets to reduce their internal development costs and significantly accelerate their product development cycles.

  20. Isospinning baby Skyrmion solutions

    NASA Astrophysics Data System (ADS)

    Battye, Richard A.; Haberichter, Mareike

    2013-12-01

    We perform full two-dimensional (2D) numerical relaxations of isospinning soliton solutions in the baby Skyrme model in which the global O(3) symmetry is broken by the 2D analogue of the pion mass term in the Skyrme model. In our calculations we explicitly allow the isospinning solitons to deform and to break the symmetries of the static configurations. We find that stable isospinning baby Skyrme solutions can be constructed numerically for all angular frequencies ω≤min⁡(μ,1), where μ is the mass parameter of the model. Stable, rotationally symmetric baby Skyrmion solutions for higher angular velocities are simply an artefact of the hedgehog approximation. Isospinning multisoliton solutions of topological charge B turn out to be unstable to break up into their B charge-1 constituents at some critical breakup frequency value. Furthermore, we find that for μ sufficiently large the rotational symmetry of charge-2 baby Skyrmions becomes broken at a critical angular frequency ω.

  1. The Conductivity of Solutions.

    ERIC Educational Resources Information Center

    Rayner-Canham, Geoff

    1993-01-01

    Presents historical background and modern explanations for the popular demonstration of showing conductivity of solutions through the insertion of a light-bulb conductivity tester into deionized water and water with salt in it. (PR)

  2. Risk-reducing mastectomy.

    PubMed

    Chiesa, Federica; Sacchini, Virgilio S

    2016-10-01

    Mastectomy rates have significantly increased over the last decades, likely due to the rising trend of risk-reducing mastectomies (RRM) in the treatment and prevention of breast cancer. Growing evidence suggests that aggressive risk-reducing surgical strategies are only justified in high-risk breast cancer situations. Notably, in this selected cohort of women, prophylactic mastectomies offer evident benefit for local and contralateral disease control, and may also provide a survival benefit. Nevertheless, the extent of the increasing frequency of this operation is not explained by the broadening of the medical indications alone. Here we analyze the current evidence regarding RRM, its clinical practice, and possible explanations for the rising phenomenon of aggressive surgical locoregional control strategies. PMID:26785281

  3. Reducing rotor weight

    SciTech Connect

    Cheney, M.C.

    1997-12-31

    The cost of energy for renewables has gained greater significance in recent years due to the drop in price in some competing energy sources, particularly natural gas. In pursuit of lower manufacturing costs for wind turbine systems, work was conducted to explore an innovative rotor designed to reduce weight and cost over conventional rotor systems. Trade-off studies were conducted to measure the influence of number of blades, stiffness, and manufacturing method on COE. The study showed that increasing number of blades at constant solidity significantly reduced rotor weight and that manufacturing the blades using pultrusion technology produced the lowest cost per pound. Under contracts with the National Renewable Energy Laboratory and the California Energy Commission, a 400 kW (33m diameter) turbine was designed employing this technology. The project included tests of an 80 kW (15.5m diameter) dynamically scaled rotor which demonstrated the viability of the design.

  4. Piezoelectric Energy Harvesting Solutions

    PubMed Central

    Caliò, Renato; Rongala, Udaya Bhaskar; Camboni, Domenico; Milazzo, Mario; Stefanini, Cesare; de Petris, Gianluca; Oddo, Calogero Maria

    2014-01-01

    This paper reviews the state of the art in piezoelectric energy harvesting. It presents the basics of piezoelectricity and discusses materials choice. The work places emphasis on material operating modes and device configurations, from resonant to non-resonant devices and also to rotational solutions. The reviewed literature is compared based on power density and bandwidth. Lastly, the question of power conversion is addressed by reviewing various circuit solutions. PMID:24618725

  5. Reflectance of aqueous solutions

    NASA Technical Reports Server (NTRS)

    Querry, M. R.

    1972-01-01

    The optical properties and optical constants of water and aqueous solutions were studied to develop an accurate tabulation of graphical representations of the optical constants through a broad spectrum. Manuscripts of articles are presented concerning extinction coefficients, relative specular reflectance, and temperature effect on the water spectrum. Graphs of absolute reflectance, phase shifts, index of refraction, and extinction coefficients for water, heavy water and aqueous solutions are included.

  6. Reducing volcanic risk

    USGS Publications Warehouse

    Decker, R.; Decker, B.

    1991-01-01

    The last two decades have brought major advances in research on how volcanoes work and how to monitor their changing habits. Geologic mapping as well as studies of earthquake patterns and surface deformation associated with underground movement of magma have given scientists a better view of the inner structure and dynamics of active volcanoes. With the next decade, the time has come to focuses more on applying this knowledge toward reducing the risk from volcanic activity on a worldwide basis. 

  7. Gradual extinction reduces reinstatement

    PubMed Central

    Shiban, Youssef; Wittmann, Jasmin; Weißinger, Mara; Mühlberger, Andreas

    2015-01-01

    The current study investigated whether gradually reducing the frequency of aversive stimuli during extinction can prevent the return of fear. Thirty-one participants of a three-stage procedure (acquisition, extinction and a reinstatement test on day 2) were randomly assigned to a standard extinction (SE) and gradual extinction (GE) procedure. The two groups differed only in the extinction procedure. While the SE group ran through a regular extinction process without any negative events, the frequency of the aversive stimuli during the extinction phase was gradually reduced for the GE group. The unconditioned stimulus (US) was an air blast (5 bar, 10 ms). A spider and a scorpion were used as conditioned stimuli (CS). The outcome variables were contingency ratings and physiological measures (skin conductance response, SCR and startle response). There were no differences found between the two groups for the acquisition and extinction phases concerning contingency ratings, SCR, or startle response. GE compared to SE significantly reduced the return of fear in the reinstatement test for the startle response but not for SCR or contingency ratings. This study was successful in translating the findings in rodent to humans. The results suggest that the GE process is suitable for increasing the efficacy of fear extinction. PMID:26441581

  8. Naval electrochemical corrosion reducer

    DOEpatents

    Clark, Howard L.

    1991-10-01

    A corrosion reducer for use with ships having a hull, a propeller mounted a propeller shaft and extending through the hull, bearings supporting the shaft, at least one thrust bearing and one seal. The improvement includes a current collector and a current reduction assembly for reducing the voltage between the hull and shaft in order to reduce corrosion due to electrolytic action. The current reduction assembly includes an electrical contact, the current collector, and the hull. The current reduction assembly further includes a device for sensing and measuring the voltage between the hull and the shaft and a device for applying a reverse voltage between the hull and the shaft so that the resulting voltage differential is from 0 to 0.05 volts. The current reduction assembly further includes a differential amplifier having a voltage differential between the hull and the shaft. The current reduction assembly further includes an amplifier and a power output circuit receiving signals from the differential amplifier and being supplied by at least one current supply. The current selector includes a brush assembly in contact with a slip ring over the shaft so that its potential may be applied to the differential amplifier.

  9. Reduce energy use

    SciTech Connect

    Welch, J.B.

    1997-07-01

    With the rising costs of utilities, Crystals International, Inc. (Plant City, Fla.), a producer of freeze-dried products for the chemical process industries, was exploring various methods to reduce energy consumption. For years, the firm had been concerned about energy costs, considering that dehydration is energy-intensive, with natural gas a major item in overhead expenses. The gas is used to fire boilers and provide steam to operate jet ejectors supplied by Croll-Reynolds (Westfield, NJ), which in turn supply the vacuum for the dehydration process. In efforts to increase efficiency and save money, Crystals International decided to replace two older boilers with a single, high-capacity unit. Producing 13,800 lb/h of 200-psig steam, the unit`s main purpose was to supply the plant`s two steam ejectors and a variety of other process needs. However, with the new boiler, system pressure would be increased and the ejector nozzles would see steam at 150 psig. This was a problem since the nozzles were designed to operate at 115-psig steam. To solve the problem, a pressure reducer, placed before the steam reached the nozzles was considered. However, Crystals International determined that reducing pressure promoted formation of potentially damaging condensate. The only alternative then, was to redesign the ejectors to accept the new system parameters.

  10. Minocycline reduces ethanol drinking.

    PubMed

    Agrawal, R G; Hewetson, A; George, C M; Syapin, P J; Bergeson, S E

    2011-06-01

    Alcoholism is a disease characterized by continued alcohol consumption despite recurring negative consequences. Thus, medications that reduce the drive to consume alcohol can be beneficial in treating alcoholism. The neurobiological systems that regulate alcohol consumption are complex and not fully understood. Currently, medications are available to treat alcoholism that act either by causing accumulation of a toxic metabolite of ethanol, or by targeting specific transmitter receptors. The purpose of our study was to investigate a new potential therapeutic pathway, neuroimmune interactions, for effects on ethanol consumption. We hypothesized that neuroimmune activity of brain glia may have a role in drinking. We utilized minocycline, a second generation tetracycline antibiotic that has immune modulatory actions, to test our hypothesis because it is known to suppress microglia, and to a lesser extent astroglia, activity following many types of insults to the brain. Treatment with 50mg/kg minocycline significantly reduced ethanol intake in male and female C57Bl/6J mice using a free choice voluntary drinking model. Saline injections did not alter ethanol intake. Minocycline had little effect on water intake or body weight change. The underlying mechanism whereby minocycline reduced ethanol intake requires further study. The results suggest that drugs that alter neuroimmune pathways may represent a new approach to developing additional therapies to treat alcoholism. PMID:21397005

  11. Conduction heat transfer solutions

    SciTech Connect

    VanSant, J.H.

    1983-08-01

    This text is a collection of solutions to a variety of heat conduction problems found in numerous publications, such as textbooks, handbooks, journals, reports, etc. Its purpose is to assemble these solutions into one source that can facilitate the search for a particular problem solution. Generally, it is intended to be a handbook on the subject of heat conduction. There are twelve sections of solutions which correspond with the class of problems found in each. Geometry, state, boundary conditions, and other categories are used to classify the problems. Each problem is concisely described by geometry and condition statements, and many times a descriptive sketch is also included. The introduction presents a synopsis on the theory, differential equations, and boundary conditions for conduction heat transfer. Some discussion is given on the use and interpretation of solutions. Supplementary data such as mathematical functions, convection correlations, and thermal properties are included for aiding the user in computing numerical values from the solutions. 155 figs., 92 refs., 9 tabs.

  12. Lightweight Steel Solutions for Automotive Industry

    SciTech Connect

    Lee, Hong Woo; Kim, Gyosung; Park, Sung Ho

    2010-06-15

    Recently, improvement in fuel efficiency and safety has become the biggest issue in worldwide automotive industry. Although the regulation of environment and safety has been tightened up more and more, the majority of vehicle bodies are still manufactured from stamped steel components. This means that the optimized steel solutions enable to demonstrate its ability to reduce body weight with high crashworthiness performance instead of expensive light weight materials such as Al, Mg and composites. To provide the innovative steel solutions for automotive industry, POSCO has developed AHSS and its application technologies, which is directly connected to EVI activities. EVI is a technical cooperation program with customer covering all stages of new car project from design to mass production. Integrated light weight solutions through new forming technologies such as TWB, hydroforming and HPF are continuously developed and provided for EVI activities. This paper will discuss the detailed status of these technologies especially light weight steel solutions based on innovative technologies.

  13. Lightweight Steel Solutions for Automotive Industry

    NASA Astrophysics Data System (ADS)

    Lee, Hong Woo; Kim, Gyosung; Park, Sung Ho

    2010-06-01

    Recently, improvement in fuel efficiency and safety has become the biggest issue in worldwide automotive industry. Although the regulation of environment and safety has been tightened up more and more, the majority of vehicle bodies are still manufactured from stamped steel components. This means that the optimized steel solutions enable to demonstrate its ability to reduce body weight with high crashworthiness performance instead of expensive light weight materials such as Al, Mg and composites. To provide the innovative steel solutions for automotive industry, POSCO has developed AHSS and its application technologies, which is directly connected to EVI activities. EVI is a technical cooperation program with customer covering all stages of new car project from design to mass production. Integrated light weight solutions through new forming technologies such as TWB, hydroforming and HPF are continuously developed and provided for EVI activities. This paper will discuss the detailed status of these technologies especially light weight steel solutions based on innovative technologies.

  14. Coating Reduces Ice Adhesion

    NASA Technical Reports Server (NTRS)

    Smith, Trent; Prince, Michael; DwWeese, Charles; Curtis, Leslie

    2008-01-01

    The Shuttle Ice Liberation Coating (SILC) has been developed to reduce the adhesion of ice to surfaces on the space shuttle. SILC, when coated on a surface (foam, metal, epoxy primer, polymer surfaces), will reduce the adhesion of ice by as much as 90 percent as compared to the corresponding uncoated surface. This innovation is a durable coating that can withstand several cycles of ice growth and removal without loss of anti-adhesion properties. SILC is made of a binder composed of varying weight percents of siloxane(s), ethyl alcohol, ethyl sulfate, isopropyl alcohol, and of fine-particle polytetrafluoroethylene (PTFE). The combination of these components produces a coating with significantly improved weathering characteristics over the siloxane system alone. In some cases, the coating will delay ice formation and can reduce the amount of ice formed. SILC is not an ice prevention coating, but the very high water contact angle (greater than 140 ) causes water to readily run off the surface. This coating was designed for use at temperatures near -170 F (-112 C). Ice adhesion tests performed at temperatures from -170 to 20 F (-112 to -7 C) show that SILC is a very effective ice release coating. SILC can be left as applied (opaque) or buffed off until the surface appears clear. Energy dispersive spectroscopy (EDS) and x-ray photoelectron spectroscopy (XPS) data show that the coating is still present after buffing to transparency. This means SILC can be used to prevent ice adhesion even when coating windows or other objects, or items that require transmission of optical light. Car windshields are kept cleaner and SILC effectively mitigates rain and snow under driving conditions.

  15. A class of nonideal solutions. 1: Definition and properties

    NASA Technical Reports Server (NTRS)

    Zeleznik, F. J.

    1983-01-01

    A class of nonideal solutions is defined by constructing a function to represent the composition dependence of thermodynamic properties for members of the class, and some properties of these solutions are studied. The constructed function has several useful features: (1) its parameters occur linearly; (2) it contains a logarithmic singularity in the dilute solution region and contains ideal solutions and regular solutions as special cases; and (3) it is applicable to N-ary systems and reduces to M-ary systems (M or = N) in a form-invariant manner.

  16. Laser-induced copper deposition with weak reducing agents

    NASA Astrophysics Data System (ADS)

    Kochemirovsky, V. A.; Fateev, S. A.; Logunov, L. S.; Tumkin, I. I.; Safonov, S. V.; Khairullina, E. M.

    2013-11-01

    The study showed that organic alcohols with 1,2,3,5,6 hydroxyl groups can be used as reducing agents for laser-induced copper deposition from solutions (LCLD).Multiatomic alcohols, sorbitol, xylitol, and glycerol, are shown to be effective reducing agents for performing LCLD at glass-ceramic surfaces. High-conductivity copper tracks with good topology were synthesized.

  17. Construction and characterization of hybrid nanoparticles via block copolymer blends and kinetic control of solution assembly

    NASA Astrophysics Data System (ADS)

    Chen, Yingchao

    vesicles, vesicle-cylinder connected nanoparticles, and disk-cylinder nanoparticles. It is discovered that smaller, kinetically-trapped, blended nanoparticles are observed with faster water addition rates, compared with larger, non-blended distinct nanoparticles with separate, unique geometries formed with slower water addition rate. The revealed rules were then applied in constructing new multicompartment hybrid nanoparticles with designed geometries, including the hybrid disks, hybrid cylinders and star-like nanoparticles. The second objective of this work was to explore a method for making hierarchical nanoparticle superstructures with designed functionality and subsequent multistep assembly and interparticle crosslinking. Advanced imaging of various nanostructures in different solution assembly systems was also generated. Together, the ideas of parameter control, kinetic study, and design of molecules and functionality presented in this dissertation will facilitate future work and nanotechnology development.

  18. Efinaconazole 10% Solution

    PubMed Central

    Reece, Barry; Smith, Kathleen; Miller, Terri

    2013-01-01

    Background: Onychomycosis is a chronic condition that often requires long-term management to eradicate the causative fungus, allow a healthy nail to grow, and prevent relapse. As a successful outcome depends highly on patient adherence with treatment, a low risk of periungual skin irritation with topical medication is clinically relevant. Objectives: To study the potential for efinaconazole 10% solution and its corresponding vehicle to induce delayed contact skin sensitization and evaluate its skin irritation potential. Methods: Efinaconazole 10% solution and its vehicle were studied in 239 healthy volunteers for the potential to induce contact skin sensitization. This included a series of induction, challenge, and re-challenge phases. An additional 21-day cumulative irritation study was undertaken in 35 healthy volunteers to compare three concentrations of efinaconazole (1%, 5%, and 10%), vehicle, and positive/negative controls. Results: There was no evidence of induced contact sensitization under occlusive, semi-occlusive, and open (open rub-in) applications of efinaconazole 10% solution. Efinaconazole 1%, 5%, and 10% solutions have mean cumulative irritancy indices of 1.12, 1.26, and 1.18, respectively, where a range of >0 to ≤1 is classified as “mildly irritating.” Results were comparable to vehicle (1.04). Conclusion: Efinaconazole 10% solution did not cause contact sensitization and induced only minimal skin irritation in the studies completed. PMID:23556032

  19. Magnetic Control of Solutal Buoyancy Driven Convection

    NASA Technical Reports Server (NTRS)

    Ramachandran, N.; Leslie, F. W.

    2003-01-01

    Volumetric forces resulting from local density variations and gravitational acceleration cause buoyancy induced convective motion in melts and solutions. Solutal buoyancy is a result of concentration differences in an otherwise isothermal fluid. If the fluid also exhibits variations in magnetic susceptibility with concentration then convection control by external magnetic fields can be hypothesized. Magnetic control of thermal buoyancy induced convection in ferrofluids (dispersions of ferromagnetic particles in a carrier fluid) and paramagnetic fluids have been demonstrated. Here we show the nature of magnetic control of solutal buoyancy driven convection of a paramagnetic fluid, an aqueous solution of Manganese Chloride hydrate. We predict the critical magnetic field required for balancing gravitational solutal buoyancy driven convection and validate it through a simple experiment. We demonstrate that gravity driven flow can be completely reversed by a magnetic field but the exact cancellation of the flow is not possible. This is because the phenomenon is unstable. The technique can be applied to crystal growth processes in order to reduce convection and to heat exchanger devices for enhancing convection. The method can also be applied to impose a desired g-level in reduced gravity applications.

  20. Solution synthesis of germanium nanocrystals

    DOEpatents

    Gerung, Henry; Boyle, Timothy J.; Bunge, Scott D.

    2009-09-22

    A method for providing a route for the synthesis of a Ge(0) nanometer-sized material from. A Ge(II) precursor is dissolved in a ligand heated to a temperature, generally between approximately 100.degree. C. and 400.degree. C., sufficient to thermally reduce the Ge(II) to Ge(0), where the ligand is a compound that can bond to the surface of the germanium nanomaterials to subsequently prevent agglomeration of the nanomaterials. The ligand encapsulates the surface of the Ge(0) material to prevent agglomeration. The resulting solution is cooled for handling, with the cooling characteristics useful in controlling the size and size distribution of the Ge(0) materials. The characteristics of the Ge(II) precursor determine whether the Ge(0) materials that result will be nanocrystals or nanowires.